Compare commits

..

2 Commits
4.11 ... 4.8.1

Author SHA1 Message Date
Nico Huber
6794ce02d4 Makefile.inc: Drop spurious -t from cbfstool add-payload
The `-t` argument was never required for `add-payload` and results in
a warning now because the type was renamed.

TEST=Built with BUILD_TIMELESS=1 and compared binaries with and without
     this patch.

Change-Id: I6ccb70acc6e88a602b90c625040d4f05d8e3630a
Signed-off-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.coreboot.org/26332
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
2018-05-16 19:00:17 +00:00
Ronald G. Minnich
5f0b80b880 Revert "cbfs/payload type: Fix build warning and whitespace in name"
This reverts commit 717ba74836.

This breaks seabios and a few other payloads. This is not
ready for use.

Change-Id: I48ebe2e2628c11e935357b900d01953882cd20dd
Signed-off-by: Ronald G. Minnich <rminnich@gmail.com>
Reviewed-on: https://review.coreboot.org/26310
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Julius Werner <jwerner@chromium.org>
Reviewed-by: Werner Zeh <werner.zeh@siemens.com>
Reviewed-by: Patrick Georgi <pgeorgi@google.com>
Reviewed-on: https://review.coreboot.org/26331
2018-05-16 19:00:09 +00:00
11571 changed files with 529562 additions and 544367 deletions

View File

@@ -17,9 +17,6 @@
--ignore CONFIG_DESCRIPTION
--ignore MISSING_SPACE
--ignore CORRUPTED_PATCH
--ignore SPDX_LICENSE_TAG
--ignore UNDOCUMENTED_DT_STRING
--ignore PRINTK_WITHOUT_KERN_LEVEL
# FILE_PATH_CHANGES seems to not be working correctly. It will
# choke on added / deleted files even if the MAINTAINERS file

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@@ -1,21 +1,10 @@
BasedOnStyle: LLVM
Language: Cpp
IndentWidth: 8
UseTab: Always
BreakBeforeBraces: Linux
AllowShortIfStatementsOnASingleLine: false
IndentCaseLabels: false
SortIncludes: false
ContinuationIndentWidth: 8
ColumnLimit: 96
AlwaysBreakBeforeMultilineStrings: true
AllowShortLoopsOnASingleLine: false
AllowShortFunctionsOnASingleLine: false
AlignEscapedNewlinesLeft: false
AlignTrailingComments: true
AllowAllParametersOfDeclarationOnNextLine: false
AlignAfterOpenBracket: true
SpaceAfterCStyleCast: false
MaxEmptyLinesToKeep: 2
BreakBeforeBinaryOperators: NonAssignment
BreakStringLiterals: false
BasedOnStyle: LLVM
Language: Cpp
IndentWidth: 8
UseTab: Always
BreakBeforeBraces: Linux
AllowShortIfStatementsOnASingleLine: false
IndentCaseLabels: false
SortIncludes: false
ContinuationIndentWidth: 8
ColumnLimit: 80

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@@ -1,11 +0,0 @@
# EditorConfig: https://EditorConfig.org
root = true
[*]
indent_style = tab
tab_width = 8
charset = utf-8
insert_final_newline = true
end_of_line = lf
trim_trailing_whitespace = true

20
.gitignore vendored
View File

@@ -16,7 +16,6 @@ payloads/coreinfo/lp.config*
payloads/external/depthcharge/depthcharge/
payloads/external/FILO/filo/
payloads/external/GRUB2/grub2/
payloads/external/LinuxBoot/linuxboot/
payloads/external/SeaBIOS/seabios/
payloads/external/tianocore/tianocore/
payloads/external/tint/tint/
@@ -56,7 +55,6 @@ site-local
*.\#
*.bin
*.debug
!Kconfig.debug
*.elf
*.o
*.out
@@ -88,7 +86,6 @@ util/archive/archive
util/bimgtool/bimgtool
util/bincfg/bincfg
util/board_status/board-status
util/bucts/bucts
util/cbfstool/cbfs-compression-tool
util/cbfstool/cbfstool
util/cbfstool/fmaptool
@@ -102,6 +99,7 @@ util/futility/futility
util/genprof/genprof
util/getpir/getpir
util/ifdtool/ifdtool
util/ifdfake/ifdfake
util/intelmetool/intelmetool
util/inteltool/.dependencies
util/inteltool/inteltool
@@ -124,12 +122,16 @@ util/autoport/autoport
util/kbc1126/kbc1126_ec_dump
util/kbc1126/kbc1126_ec_insert
Documentation/*.aux
Documentation/*.idx
Documentation/*.log
Documentation/*.toc
Documentation/*.out
Documentation/*.pdf
documentation/*.aux
documentation/*.idx
documentation/*.log
documentation/*.toc
documentation/*.out
documentation/*.pdf
documentation/cpukconfig.tex
documentation/mainboardkconfig.tex
documentation/skconfig.tex
documentation/socketfkconfig.tex
Documentation/_build
doxygen/*

21
.gitmodules vendored
View File

@@ -21,24 +21,3 @@
[submodule "libgfxinit"]
path = 3rdparty/libgfxinit
url = ../libgfxinit.git
[submodule "3rdparty/fsp"]
path = 3rdparty/fsp
url = ../fsp.git
update = none
ignore = dirty
[submodule "opensbi"]
path = 3rdparty/opensbi
url = ../opensbi.git
[submodule "intel-microcode"]
path = 3rdparty/intel-microcode
url = ../intel-microcode.git
update = none
ignore = dirty
[submodule "3rdparty/ffs"]
path = 3rdparty/ffs
url = ../ffs.git
[submodule "3rdparty/amd_blobs"]
path = 3rdparty/amd_blobs
url = ../amd_blobs
update = none
ignore = dirty

1
3rdparty/amd_blobs vendored

Submodule 3rdparty/amd_blobs deleted from cf227316b0

2
3rdparty/blobs vendored

1
3rdparty/ffs vendored

Submodule 3rdparty/ffs deleted from 3ec70fbc45

1
3rdparty/fsp vendored

Submodule 3rdparty/fsp deleted from 59964173e1

1
3rdparty/opensbi vendored

Submodule 3rdparty/opensbi deleted from 215421ca61

2
3rdparty/vboot vendored

127
AUTHORS
View File

@@ -1,127 +0,0 @@
# This is the list of coreboot authors for copyright purposes.
#
# This does not necessarily list everyone who has contributed code, since in
# some cases, their employer may be the copyright holder. To see the full list
# of contributors, and their email addresses, see the revision history in source
# control.
# Run the below commands in the coreboot repo for additional information.
# To see a list of contributors: git log --pretty=format:%an | sort | uniq
# For patches adding or removing a name: git log -i -S "NAME" --source --all
9elements Agency GmbH
Advanced Micro Devices, Inc.
Alex Züpke
Alexander Couzens
Alexandru Gagniuc
Analog Devices Inc.
Andy Fleming
ARM Limited and Contributors
Arthur Heymans
ASPEED Technology Inc.
Atheros Corporation
Atmel Corporation
Carl-Daniel Hailfinger
coresystems GmbH
Damien Zammit
David Brownell
David Hendricks
David Mosberger-Tang
Denis Dowling
DENX Software Engineering
DMP Electronics Inc.
Drew Eckhardt
Egbert Eich
Eltan B.V
Eric Biederman
Eswar Nallusamy
Facebook, Inc.
Felix Held
Frederic Potter
Free Software Foundation, Inc.
Freescale Semiconductor, Inc.
Gary Jennejohn
Gerd Hoffmann
Google LLC
Greg Watson
Idwer Vollering
Imagination Technologies
Infineon Technologies
Intel Corporation
Jason Zhao
Jonathan Neuschäfer
Jordan Crouse
Joseph Smith
Keith Hui
Keith Packard
Kshitij
Kyösti Mälkki
Lei Wen
Li-Ta Lo
Libra Li
Linus Torvalds
Linux Networx, Inc.
Luc Verhaegen
Marc Jones
Marek Vasut
Marius Gröger
Martin Mares
Marvell International Ltd.
Marvell Semiconductor Inc.
MediaTek Inc.
MontaVista Software, Inc.
Myles Watson
Network Appliance Inc.
Nicholas Sielicki
Nick Barker
Nico Huber
Ollie Lo
Orion Technologies, LLC
Patrick Georgi
Patrick Rudolph
PC Engines GmbH
Per Odlund
Peter Stuge
Raptor Engineering, LLC
Red Hat Inc
Reinhard Meyer
Richard Woodruff
Ronald G. Minnich
Rudolf Marek
Russell King
Sage Electronic Engineering, LLC
Samsung Electronics
SciTech Software, Inc.
Sebastian Grzywna
secunet Security Networks AG
Siemens AG
Silicon Integrated System Corporation
Stefan Reinauer
Steve Magnani
ST Microelectronics
SUSE LINUX AG
Sven Schnelle
Syed Mohammed Khasim
Texas Instruments
The Linux Foundation
Thomas Winischhofer
Timothy Pearson
Tungsten Graphics, Inc.
Tyan Computer Corp.
ucRobotics Inc.
Uwe Hermann
VIA Technologies, Inc
Vipin Kumar
Ward Vandewege
Wolfgang Denk
Yinghai Lu
# Directories transferred
src/acpi
src/arch
src/commonlib
src/console
src/cpu
src/device
src/drivers

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@@ -0,0 +1,162 @@
<html>
<head>
<title>Galileo Implementation Status</title>
</title>
<body>
<h1>Galileo Implementation Status<br>2016/07/08 06:51:34 PDT</h1>
<table>
<tr><td colspan=2><b>Legend</b></td></tr>
<tr><td bgcolor="#ffc0c0">Red</td><td>Required - To-be-implemented</td></tr>
<tr><td bgcolor="#ffffc0">Yellow</td><td>Optional</td></tr>
<tr><td bgcolor="#c0ffc0">Green</td><td>Implemented</td></tr>
</table>
<table>
<tr valign="top">
<td>
<table border=1>
<tr><th colspan=2>bootblock: 100% Done</th></tr>
<tr><th>Type</th><th>Routine</td></tr>
<tr bgcolor=#ffffc0><td>Optional</td><td>bootblock_c_entry</td></tr>
<tr bgcolor=#c0ffc0><td>Required</td><td>bootblock_main_with_timestamp</td></tr>
<tr bgcolor=#ffffc0><td>Optional</td><td>bootblock_mainboard_early_init</td></tr>
<tr bgcolor=#ffffc0><td>Optional</td><td>bootblock_mainboard_init</td></tr>
<tr bgcolor=#c0ffc0><td>Required</td><td>bootblock_pre_c_entry</td></tr>
<tr bgcolor=#c0ffc0><td>Required</td><td>bootblock_protected_mode_entry</td></tr>
<tr bgcolor=#c0ffc0><td>Required</td><td>bootblock_soc_early_init</td></tr>
<tr bgcolor=#ffffc0><td>Optional</td><td>bootblock_soc_init</td></tr>
<tr bgcolor=#c0ffc0><td>Required</td><td>tsc_freq_mhz</td></tr>
<tr bgcolor=#c0ffc0><td>Required</td><td>uart_init</td></tr>
</table>
</td>
<td width=5>&nbsp;</td>
<td>
<table border=1>
<tr><th colspan=2>romstage: 67% Done</th></tr>
<tr><th>Type</th><th>Routine</td></tr>
<tr bgcolor=#ffffc0><td>Optional</td><td>arch_segment_loaded</td></tr>
<tr bgcolor=#ffffc0><td>Optional</td><td>backup_top_of_ram</td></tr>
<tr bgcolor=#ffffc0><td>Optional</td><td>boot_device_init</td></tr>
<tr bgcolor=#ffffc0><td>Optional</td><td>car_mainboard_post_console_init</td></tr>
<tr bgcolor=#c0ffc0><td>Required</td><td>car_mainboard_pre_console_init</td></tr>
<tr bgcolor=#c0ffc0><td>Required</td><td>car_soc_post_console_init</td></tr>
<tr bgcolor=#c0ffc0><td>Required</td><td>car_soc_pre_console_init</td></tr>
<tr bgcolor=#c0ffc0><td>Required</td><td>car_stage_entry</td></tr>
<tr bgcolor=#c0ffc0><td>Required</td><td>cbfs_master_header_locator</td></tr>
<tr bgcolor=#ffffc0><td>Optional</td><td>cbmem_fail_resume</td></tr>
<tr bgcolor=#ffffc0><td>Optional</td><td>clear_recovery_mode_switch</td></tr>
<tr bgcolor=#ffffc0><td>Optional</td><td>cpu_smi_handler</td></tr>
<tr bgcolor=#c0ffc0><td>Required</td><td>fill_power_state</td></tr>
<tr bgcolor=#ffffc0><td>Optional</td><td>get_sw_write_protect_state</td></tr>
<tr bgcolor=#ffffc0><td>Optional</td><td>get_top_of_ram</td></tr>
<tr bgcolor=#ffffc0><td>Optional</td><td>gpio_acpi_path</td></tr>
<tr bgcolor=#c0ffc0><td>Required</td><td>init_timer</td></tr>
<tr bgcolor=#ffffc0><td>Optional</td><td>mainboard_add_dimm_info</td></tr>
<tr bgcolor=#ffffc0><td>Optional</td><td>mainboard_check_ec_image</td></tr>
<tr bgcolor=#ffc0c0><td>Required</td><td>mainboard_fill_spd_data</td></tr>
<tr bgcolor=#ffffc0><td>Optional</td><td>mainboard_io_trap_handler</td></tr>
<tr bgcolor=#ffc0c0><td>Required</td><td>mainboard_memory_init_params</td></tr>
<tr bgcolor=#ffffc0><td>Optional</td><td>mainboard_post</td></tr>
<tr bgcolor=#c0ffc0><td>Required</td><td>mainboard_romstage_entry</td></tr>
<tr bgcolor=#ffffc0><td>Optional</td><td>mainboard_save_dimm_info</td></tr>
<tr bgcolor=#ffffc0><td>Optional</td><td>mainboard_smi_apmc</td></tr>
<tr bgcolor=#ffffc0><td>Optional</td><td>mainboard_smi_gpi</td></tr>
<tr bgcolor=#ffffc0><td>Optional</td><td>mainboard_smi_sleep</td></tr>
<tr bgcolor=#ffffc0><td>Optional</td><td>map_oprom_vendev</td></tr>
<tr bgcolor=#ffc0c0><td>Required</td><td>migrate_power_state</td></tr>
<tr bgcolor=#ffc0c0><td>Required</td><td>mrc_cache_get_current_with_version</td></tr>
<tr bgcolor=#ffc0c0><td>Required</td><td>mrc_cache_stash_data_with_version</td></tr>
<tr bgcolor=#ffffc0><td>Optional</td><td>platform_prog_run</td></tr>
<tr bgcolor=#ffffc0><td>Optional</td><td>platform_segment_loaded</td></tr>
<tr bgcolor=#c0ffc0><td>Required</td><td>print_fsp_info</td></tr>
<tr bgcolor=#c0ffc0><td>Required</td><td>raminit</td></tr>
<tr bgcolor=#c0ffc0><td>Required</td><td>ramstage_cache_invalid</td></tr>
<tr bgcolor=#ffc0c0><td>Required</td><td>report_memory_config</td></tr>
<tr bgcolor=#c0ffc0><td>Required</td><td>romstage_common</td></tr>
<tr bgcolor=#ffffc0><td>Optional</td><td>save_chromeos_gpios</td></tr>
<tr bgcolor=#ffc0c0><td>Required</td><td>set_max_freq</td></tr>
<tr bgcolor=#c0ffc0><td>Required</td><td>setup_stack_and_mtrrs</td></tr>
<tr bgcolor=#ffc0c0><td>Required</td><td>smm_region</td></tr>
<tr bgcolor=#ffc0c0><td>Required</td><td>smm_region_size</td></tr>
<tr bgcolor=#c0ffc0><td>Required</td><td>soc_after_ram_init</td></tr>
<tr bgcolor=#c0ffc0><td>Required</td><td>soc_display_memory_init_params</td></tr>
<tr bgcolor=#c0ffc0><td>Required</td><td>soc_display_mtrrs</td></tr>
<tr bgcolor=#c0ffc0><td>Required</td><td>soc_get_variable_mtrr_count</td></tr>
<tr bgcolor=#c0ffc0><td>Required</td><td>soc_memory_init_params</td></tr>
<tr bgcolor=#ffffc0><td>Optional</td><td>soc_pre_ram_init</td></tr>
<tr bgcolor=#ffffc0><td>Optional</td><td>southbridge_smi_handler</td></tr>
<tr bgcolor=#ffffc0><td>Optional</td><td>stage_cache_add</td></tr>
<tr bgcolor=#ffffc0><td>Optional</td><td>stage_cache_load_stage</td></tr>
<tr bgcolor=#ffffc0><td>Optional</td><td>timestamp_get</td></tr>
<tr bgcolor=#c0ffc0><td>Required</td><td>tsc_freq_mhz</td></tr>
<tr bgcolor=#ffffc0><td>Optional</td><td>vb2ex_hwcrypto_digest_extend</td></tr>
<tr bgcolor=#ffffc0><td>Optional</td><td>vb2ex_hwcrypto_digest_finalize</td></tr>
<tr bgcolor=#ffffc0><td>Optional</td><td>vb2ex_hwcrypto_digest_init</td></tr>
<tr bgcolor=#ffffc0><td>Optional</td><td>vboot_platform_prepare_reboot</td></tr>
<tr bgcolor=#ffffc0><td>Optional</td><td>verstage_mainboard_init</td></tr>
</table>
</td>
<td width=5>&nbsp;</td>
<td>
<table border=1>
<tr><th colspan=2>ramstage: 60% Done</th></tr>
<tr><th>Type</th><th>Routine</td></tr>
<tr bgcolor=#ffc0c0><td>Required</td><td>acpi_create_serialio_ssdt</td></tr>
<tr bgcolor=#ffffc0><td>Optional</td><td>arch_segment_loaded</td></tr>
<tr bgcolor=#ffffc0><td>Optional</td><td>backup_top_of_ram</td></tr>
<tr bgcolor=#ffffc0><td>Optional</td><td>boot_device_init</td></tr>
<tr bgcolor=#c0ffc0><td>Required</td><td>cbfs_master_header_locator</td></tr>
<tr bgcolor=#ffffc0><td>Optional</td><td>cbmem_fail_resume</td></tr>
<tr bgcolor=#ffffc0><td>Optional</td><td>clear_recovery_mode_switch</td></tr>
<tr bgcolor=#ffffc0><td>Optional</td><td>cpu_smi_handler</td></tr>
<tr bgcolor=#ffffc0><td>Optional</td><td>fw_cfg_acpi_tables</td></tr>
<tr bgcolor=#ffffc0><td>Optional</td><td>get_sw_write_protect_state</td></tr>
<tr bgcolor=#ffffc0><td>Optional</td><td>get_top_of_ram</td></tr>
<tr bgcolor=#ffffc0><td>Optional</td><td>gpio_acpi_path</td></tr>
<tr bgcolor=#c0ffc0><td>Required</td><td>init_timer</td></tr>
<tr bgcolor=#ffffc0><td>Optional</td><td>lb_board</td></tr>
<tr bgcolor=#ffffc0><td>Optional</td><td>lb_framebuffer</td></tr>
<tr bgcolor=#ffffc0><td>Optional</td><td>mainboard_add_dimm_info</td></tr>
<tr bgcolor=#ffffc0><td>Optional</td><td>mainboard_io_trap_handler</td></tr>
<tr bgcolor=#ffffc0><td>Optional</td><td>mainboard_post</td></tr>
<tr bgcolor=#ffffc0><td>Optional</td><td>mainboard_silicon_init_params</td></tr>
<tr bgcolor=#ffffc0><td>Optional</td><td>mainboard_smi_apmc</td></tr>
<tr bgcolor=#ffffc0><td>Optional</td><td>mainboard_smi_gpi</td></tr>
<tr bgcolor=#ffffc0><td>Optional</td><td>mainboard_smi_sleep</td></tr>
<tr bgcolor=#ffffc0><td>Optional</td><td>mainboard_suspend_resume</td></tr>
<tr bgcolor=#ffffc0><td>Optional</td><td>map_oprom_vendev</td></tr>
<tr bgcolor=#ffffc0><td>Optional</td><td>mirror_payload</td></tr>
<tr bgcolor=#ffffc0><td>Optional</td><td>northbridge_smi_handler</td></tr>
<tr bgcolor=#ffffc0><td>Optional</td><td>nvm_mmio_to_flash_offset</td></tr>
<tr bgcolor=#ffffc0><td>Optional</td><td>platform_prog_run</td></tr>
<tr bgcolor=#ffffc0><td>Optional</td><td>platform_segment_loaded</td></tr>
<tr bgcolor=#ffffc0><td>Optional</td><td>save_chromeos_gpios</td></tr>
<tr bgcolor=#ffffc0><td>Optional</td><td>smbios_mainboard_bios_version</td></tr>
<tr bgcolor=#ffffc0><td>Optional</td><td>smbios_mainboard_manufacturer</td></tr>
<tr bgcolor=#ffffc0><td>Optional</td><td>smbios_mainboard_product_name</td></tr>
<tr bgcolor=#ffffc0><td>Optional</td><td>smbios_mainboard_serial_number</td></tr>
<tr bgcolor=#ffffc0><td>Optional</td><td>smbios_mainboard_set_uuid</td></tr>
<tr bgcolor=#c0ffc0><td>Required</td><td>smbios_mainboard_version</td></tr>
<tr bgcolor=#ffffc0><td>Optional</td><td>smm_disable_busmaster</td></tr>
<tr bgcolor=#ffffc0><td>Optional</td><td>soc_after_silicon_init</td></tr>
<tr bgcolor=#c0ffc0><td>Required</td><td>soc_display_silicon_init_params</td></tr>
<tr bgcolor=#ffc0c0><td>Required</td><td>soc_fill_acpi_wake</td></tr>
<tr bgcolor=#c0ffc0><td>Required</td><td>soc_silicon_init_params</td></tr>
<tr bgcolor=#ffffc0><td>Optional</td><td>soc_skip_ucode_update</td></tr>
<tr bgcolor=#ffffc0><td>Optional</td><td>southbridge_smi_handler</td></tr>
<tr bgcolor=#ffffc0><td>Optional</td><td>stage_cache_add</td></tr>
<tr bgcolor=#ffffc0><td>Optional</td><td>stage_cache_load_stage</td></tr>
<tr bgcolor=#ffc0c0><td>Required</td><td>timestamp_get</td></tr>
<tr bgcolor=#ffc0c0><td>Required</td><td>timestamp_tick_freq_mhz</td></tr>
<tr bgcolor=#c0ffc0><td>Required</td><td>tsc_freq_mhz</td></tr>
<tr bgcolor=#ffffc0><td>Optional</td><td>vb2ex_hwcrypto_digest_extend</td></tr>
<tr bgcolor=#ffffc0><td>Optional</td><td>vb2ex_hwcrypto_digest_finalize</td></tr>
<tr bgcolor=#ffffc0><td>Optional</td><td>vb2ex_hwcrypto_digest_init</td></tr>
<tr bgcolor=#ffffc0><td>Optional</td><td>wifi_regulatory_domain</td></tr>
<tr bgcolor=#ffffc0><td>Optional</td><td>write_smp_table</td></tr>
</table>
</td>
<td width=5>&nbsp;</td>
</tr>
</table>
</body>
</html>

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@@ -17,6 +17,7 @@
<li><a target="_blank" href="../SoC/soc.html">SoC</a> support</li>
<li><a target="_blank" href="../fsp1_1.html">FSP 1.1</a> integration</li>
<li><a target="_blank" href="board.html">Board</a> support</li>
<li><a target="_blank" href="Galileo_checklist.html">Implementation Checklist</a></li>
</ul>
</td>
</tr>

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@@ -0,0 +1,74 @@
# Intel Common Code Block Publishing EFI_MP_SERVICES_PPI
## Introduction
This documentation is intended to document the purpose for creating EFI service
Interface inside coreboot space to perform CPU feature programming on Application
Processors for Intel 9th Gen (Cannon Lake) and beyond CPUs.
Today coreboot is capable enough to handle multi-processor initialization on IA platforms.
The multi-processor initialization code has to take care of lots of duties:
1 Bringing all cores out of reset
2 Load latest microcode on all cores
3 Sync latest MTRR snapshot between BSP and APs
4 Perform sets of CPU feature programming
* CPU Power & Thermal Management
* Overclocking
* Intel Trusted Execution Technology
* Intel Software Guard Extensions
* Intel Processor Trace etc.
This above CPU feature programming lists are expected to grow with current and future
CPU complexity and there might be some cases where certain feature programming mightbe
closed source in nature.
Platform code might need to compromise on those closed source nature of CPU programming
if we don't plan to provide an alternate interface which can be used by coreboot to
get-rid of such close source CPU programming.
## Proposal
As coreboot is doing CPU multi-processor initialization for IA platform before FSP-S
initialization and having all possible information about cores in terms of maximum number
of cores, APIC ids, stack size etc. Its also possible for coreboot to extend its own
support model and create a sets of APIs which later can be used by FSP to run CPU feature
programming using coreboot published APIs.
Due to the fact that FSP is using EFI infrastructure and need to relying on install/locate
PPI to perform certain API call, hence coreboot has to created MP services APIs known as
EFI_MP_SERVICES_PPI as per PI specification volume 1, section 8.3.9.
More details here: http://www.uefi.org/sites/default/files/resources/PI_Spec_1_6.pdf
### coreboot to publish EFI_MP_SERVICES_PPI APIs
| API | Description |
|------------------------------|------------------------------------------------------------------|
| PeiGetNumberOfProcessors | Get the number of CPU's. |
| PeiGetProcessorInfo | Get information on a specific CPU. |
| PeiStartupAllAPs | Activate all of the application processors. |
| PeiStartupThisAP | Activate a specific application processor. |
| PeiSwitchBSP | Switch the boot strap processor. |
| PeiEnableDisableAP | Enable or disable an application processor. |
| PeiWhoAmI | Identify the currently executing processor. |
|------------------------------|------------------------------------------------------------------|
## Code Flow
Here is proposed design flow with coreboot has implemented EFI_MP_SERVICES_PPI API and FSP will make
use of the same to perform some CPU feature programming.
** coreboot-FSP MP init flow **
![alt text][coreboot_publish_mp_service_api]
[coreboot_publish_mp_service_api]: coreboot_publish_mp_service_api.png "coreboot-fsp mp init flow"
## Benefits
1. coreboot was using SkipMpInit=1 which will skip entire FSP CPU feature programming.
With proposed model, coreboot will make use of SkipMpInit=0 which will allow to run all
Silicon recommended CPU programming.
2. CPU feature programming inside FSP will be more transparent than before as its using
coreboot interfaces to execute those programming.
3. coreboot will have more control over running those feature programming as API optimization
handled by coreboot.

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# Sandy Bridge Raminit
## Introduction
This documentation is intended to document the closed source memory controller
hardware for Intel 2nd Gen (Sandy Bride) and 3rd Gen (Ivy Bridge) core-i CPUs.
The memory initialization code has to take care of lots of duties:
1. Selection of operating frequency
* Selection of common timings
* Applying frequency specific compensation values
* Read training of all populated channels
* Write training of all populated channels
* Adjusting delay networks of address and command signals
* DQS training of all populated channels
* Programming memory map
* Report DRAM configuration
* Error handling
## Definitions
```eval_rst
+---------+-------------------------------------------------------------------+------------+--------------+
| Symbol | Description | Units | Valid region |
+=========+===================================================================+============+==============+
| SCK | DRAM system clock cycle time | s | |
+---------+-------------------------------------------------------------------+------------+--------------+
| tCK | DRAM system clock cycle time | 1/256th ns | |
+---------+-------------------------------------------------------------------+------------+--------------+
| DCK | Data clock cycle time: The time between two SCK clock edges | s | |
+---------+-------------------------------------------------------------------+------------+--------------+
| timA | IO phase: The phase delay of the IO signals | 1/64th DCK | [0-512) |
+---------+-------------------------------------------------------------------+------------+--------------+
| SPD | Manufacturer set memory timings located on an EEPROM on every DIMM| bytes | |
+---------+-------------------------------------------------------------------+------------+--------------+
| REFCK | Reference clock, either 100 or 133 | Mhz | 100, 133 |
+---------+-------------------------------------------------------------------+------------+--------------+
| MULT | DRAM PLL multiplier | | [3-12] |
+---------+-------------------------------------------------------------------+------------+--------------+
| XMP | Extreme Memory Profiles | | |
+---------+-------------------------------------------------------------------+------------+--------------+
```
## (Inoffical) register documentation
- [Sandy Bride - Register documentation](SandyBridge_registers.md)
## Frequency selection
- [Sandy Bride - Frequency selection](Sandybridge_freq.md)
## Read training
- [Sandy Bride - Read training](Sandybridge_read.md)
### SMBIOS type 17
The SMBIOS specification allows to report the memory configuration in use.
On GNU/Linux you can run `# dmidecode -t 17` to view it.
Example output of dmidecode:
```
Handle 0x0045, DMI type 17, 34 bytes
Memory Device
Array Handle: 0x0042
Error Information Handle: Not Provided
Total Width: 64 bits
Data Width: 64 bits
Size: 8192 MB
Form Factor: DIMM
Set: None
Locator: ChannelB-DIMM0
Bank Locator: BANK 2
Type: DDR3
Type Detail: Synchronous
Speed: 933 MHz
Manufacturer: 0420
Serial Number: 00000000
Asset Tag: 9876543210
Part Number: F3-1866C9-8GSR
Rank: 2
Configured Clock Speed: 933 MHz
```
The memory frequency printed by dmidecode is the active memory frequency. It's
**not** the double datarate and it's **not** the one encoded maximum frequency
in each DIMM's SPD.
> **Note:** This feature is available since coreboot 4.4
### MRC cache
The name *MRC cache* might be missleading as in case of *Native ram init*
there's no MRC, but for historical reasons it's still named *MRC cache*.
The MRC cache is part of flash memory that is writeable by coreboot.
At the end of the boot process coreboot will write the RAM training results to
flash for future use, as RAM training is time intensive. Storing the results
allows to boot faster on normal boot and allows to support S3 resume,
as the RAM training results can't be stored in RAM (you need to configure
the memory controller first to access RAM).
The MRC cache needs to be invalidated in case the memory configuration has
been changed. To detect a changed memory configuration the CRC16 of each DIMM
is stored to MRC cache.
> **Note:** This feature is available since coreboot 4.4
### Error handling
As of writing the only supported error handling is to disable the failing
channel and restart the memory training sequence. It's very likely to succeed,
as memory channels operate independent of each other.
In case no DIMM could be initilized coreboot will halt. The screen will stay
black until you power of your device. On some platforms there's additional
feedback to indicate such an event.
If you find `dmidecode -t 17` to report only half of the memory installed,
it's likely that a fatal memory init failure had happened.
It is assumed, that a working board with less physical memory, is much better,
than a board that doesn't boot at all.
> **Note:** This feature is available since coreboot 4.5
Try to swap memory modules and or try to use a different vendor. If nothing
helps you could have a look at capter [Debuggin] or report a ticket
at [ticket.coreboot.org]. Please provide a full RAM init log,
that has been captured using EHCI debug.
To enable extensive RAM training logging enable the Kconfig option
`DEBUG_RAM_SETUP`
#### Lenovo Thinkpads
Lenovo Thinkpads do have an additional feature to indicate that RAM init has
failed and coreboot has died (it calls die() on fatal error, thus the name).
The Kconfig options
`H8_BEEP_ON_DEATH`
`H8_FLASH_LEDS_ON_DEATH`
enable blinking LEDs and enable a beep to indicate death.
> **Note:** This feature is available since coreboot 4.7
## Debugging
It's recommended to use an external debugger, such as serial or EHCI debug
dongle. In case of failing memory init the board might not boot at all,
preventing you from using CBMEM.

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# Frequency selection
## Introduction
This chapter explains the frequency selection done on Sandybride and Ivybridge.
## Definitions
```eval_rst
+---------+-------------------------------------------------------------------+------------+--------------+
| Symbol | Description | Units | Valid region |
+=========+===================================================================+============+==============+
| SCK | DRAM system clock cycle time | s | |
+---------+-------------------------------------------------------------------+------------+--------------+
| tCK | DRAM system clock cycle time | 1/256th ns | |
+---------+-------------------------------------------------------------------+------------+--------------+
| DCK | Data clock cycle time: The time between two SCK clock edges | s | |
+---------+-------------------------------------------------------------------+------------+--------------+
| SPD | Manufacturer set memory timings located on an EEPROM on every DIMM| bytes | |
+---------+-------------------------------------------------------------------+------------+--------------+
| REFCK | Reference clock, either 100 or 133 | MHz | 100, 133 |
+---------+-------------------------------------------------------------------+------------+--------------+
| MULT | DRAM PLL multiplier | | [3-12] |
+---------+-------------------------------------------------------------------+------------+--------------+
| XMP | Extreme Memory Profiles | | |
+---------+-------------------------------------------------------------------+------------+--------------+
```
## SPD
The [SPD](https://de.wikipedia.org/wiki/Serial_Presence_Detect "Serial Presence Detect")
located on every DIMM is factory program with various timings. One of them
specifies the maximum clock frequency the DIMM should be used with. The
operating frequency is stores as fixed point value (tCK), rounded to the next
smallest supported operating frequency. Some
[SPD](https://de.wikipedia.org/wiki/Serial_Presence_Detect "Serial Presence Detect")
contains additional and optional
[XMP](https://de.wikipedia.org/wiki/Extreme_Memory_Profile "Extreme Memory Profile")
data, that stores so called "performance" modes, that advertises higher clock
frequencies.
## XMP profiles
At time of writing coreboot's raminit is able to parse XMP profile 1 and 2.
Only **XMP profile 1** is being used in case it advertises:
* 1.5V operating voltage
* The channel's installed DIMM count doesn't exceed the XMP coded limit
In case the XMP profile doesn't fullfill those limits, the regular SPD will be
used.
> **Note:** XMP Profiles are supported since coreboot 4.4.
It is possible to ignore the max DIMM count limit set by XMP profiles.
By activating Kconfig option `NATIVE_RAMINIT_IGNORE_XMP_MAX_DIMMS` it is
possible to install two DIMMs per channel, even if XMP tells you not to do.
> **Note:** Ignoring XMP Profiles limit is supported since coreboot 4.7.
## Soft fuses
Every board manufacturer does program "soft" fuses to indicate the maximum
DRAM frequency supported. However, those fuses don't set a limit in hardware
and thus are called "soft" fuses, as it is possible to ignore them.
> **Note:** Ignoring the fuses might cause system instability !
On Sandy Bride *CAPID0_A* is being read, and on Ivybridge *CAPID0_B* is being
read. coreboot reads those registers and honors the limit in case the Kconfig
option `CONFIG_NATIVE_RAMINIT_IGNORE_MAX_MEM_FUSES` wasn't set.
Power users that want to let their RAM run at DRAM's "stock" frequency need to
enable the Kconfig symbol.
It is possible to override the soft fuses limit by using a board-specific
[devicetree](#devicetree) setting.
> **Note:** Ignoring max mem freq. fuses is supported since coreboot 4.7.
## <a name="hard_fuses"></a> Hard fuses
"Hard" fuses are programmed by Intel and limit the maximum frequency that can
be used on a given CPU/board/chipset. At time of writing there's no register
to read this limit, before trying to set a given DRAM frequency. The memory PLL
won't lock, indicating that the chosen memory multiplier isn't available. In
this case coreboot tries the next smaller memory multiplier until the PLL will
lock.
## <a name="devicetree"></a> Devicetree
The devicetree register ```max_mem_clock_mhz``` overrides the "soft" fuses set
by the board manufacturer.
By using this register it's possible to force a minimum operating frequency.
## Reference clock
While Sandybride supports 133 MHz reference clock (REFCK), Ivy Bridge also
supports 100 MHz reference clock. The reference clock is multiplied by the DRAM
multiplier to select the DRAM frequency (SCK) by the following formula:
REFCK * MULT = 1 / DCK
> **Note:** Since coreboot 4.6 Ivy Bridge supports 100MHz REFCK.
## Sandy Bride's supported frequencies
```eval_rst
+------------+-----------+------------------+-------------------------+---------------+
| SCK [Mhz] | DDR [Mhz] | Mutiplier (MULT) | Reference clock (REFCK) | Comment |
+============+===========+==================+=========================+===============+
| 400 | DDR3-800 | 3 | 133 MHz | |
+------------+-----------+------------------+-------------------------+---------------+
| 533 | DDR3-1066 | 4 | 133 MHz | |
+------------+-----------+------------------+-------------------------+---------------+
| 666 | DDR3-1333 | 5 | 133 MHz | |
+------------+-----------+------------------+-------------------------+---------------+
| 800 | DDR3-1600 | 6 | 133 MHz | |
+------------+-----------+------------------+-------------------------+---------------+
| 933 | DDR3-1866 | 7 | 133 MHz | |
+------------+-----------+------------------+-------------------------+---------------+
| 1066 | DDR3-2166 | 8 | 133 MHz | |
+------------+-----------+------------------+-------------------------+---------------+
```
## Ivybridge's supported frequencies
```eval_rst
+------------+-----------+------------------+-------------------------+---------------+
| SCK [Mhz] | DDR [Mhz] | Mutiplier (MULT) | Reference clock (REFCK) | Comment |
+============+===========+==================+=========================+===============+
| 400 | DDR3-800 | 3 | 133 MHz | |
+------------+-----------+------------------+-------------------------+---------------+
| 533 | DDR3-1066 | 4 | 133 MHz | |
+------------+-----------+------------------+-------------------------+---------------+
| 666 | DDR3-1333 | 5 | 133 MHz | |
+------------+-----------+------------------+-------------------------+---------------+
| 800 | DDR3-1600 | 6 | 133 MHz | |
+------------+-----------+------------------+-------------------------+---------------+
| 933 | DDR3-1866 | 7 | 133 MHz | |
+------------+-----------+------------------+-------------------------+---------------+
| 1066 | DDR3-2166 | 8 | 133 MHz | |
+------------+-----------+------------------+-------------------------+---------------+
| 700 | DDR3-1400 | 7 | 100 MHz | '1 |
+------------+-----------+------------------+-------------------------+---------------+
| 800 | DDR3-1600 | 8 | 100 MHz | '1 |
+------------+-----------+------------------+-------------------------+---------------+
| 900 | DDR3-1800 | 9 | 100 MHz | '1 |
+------------+-----------+------------------+-------------------------+---------------+
| 1000 | DDR3-2000 | 10 | 100 MHz | '1 |
+------------+-----------+------------------+-------------------------+---------------+
| 1100 | DDR3-2200 | 11 | 100 MHz | '1 |
+------------+-----------+------------------+-------------------------+---------------+
| 1200 | DDR3-2400 | 12 | 100 MHz | '1 |
+------------+-----------+------------------+-------------------------+---------------+
```
> '1: since coreboot 4.6
## Multiplier selection
coreboot select the maximum frequency to operate at by the following formula:
```
if devicetree's max_mem_clock_mhz > 0:
freq_max := max_mem_clock_mhz
else:
freq_max := soft_fuse_max_mhz
for i in SPDs:
freq_max := MIN(freq_max, ddr_spd_max_mhz[i])
```
As you can see, by using DIMMs with different maximum DRAM frequencies, the
slowest DIMMs' frequency will be selected, to prevent over-clocking it.
The selected frequency gives the PLL multiplier to operate at. In case the PLL
locks (see Take me to [Hard fuses](#hard_fuses)) the frequency will be used for
all DIMMs. At this point it's not possible to change the multiplier again,
until the system has been powered off. In case the PLL doesn't lock, the next
smaller multiplier will be used until a working multiplier will be found.

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# Read training
## Introduction
This chapter explains the read training sequence done on Sandy Bride and
Ivy Bridge memory initialization.
Read training is done to compensate the skew between DQS and SCK and to find
the smallest supported roundtrip delay.
Every board does have a vendor depended routing topology, and can be equip
with any combination of DDR3 memory modules, that introduces different
skew between the memory lanes. With DDR3 a "Fly-By" routing topology
has been introduced, that makes the biggest part of DQS-SCK skew.
The memory code measures the actual skew and actives delay gates,
that will "compensate" the skew.
When in read training the DRAM and the controller are placed in a special mode.
On every read instruction the DRAM outputs a predefined pattern and the memory
controller samples the DQS after a given delay. As the pattern is known, the
actual delay of every lane can be measured.
The values programmed in read training effect DRAM-to-MC transfers only !
## Definitions
```eval_rst
+---------+-------------------------------------------------------------------+------------+--------------+
| Symbol | Description | Units | Valid region |
+=========+===================================================================+============+==============+
| SCK | DRAM system clock cycle time | s | |
+---------+-------------------------------------------------------------------+------------+--------------+
| tCK | DRAM system clock cycle time | 1/256th ns | |
+---------+-------------------------------------------------------------------+------------+--------------+
| DCK | Data clock cycle time: The time between two SCK clock edges | s | |
+---------+-------------------------------------------------------------------+------------+--------------+
| timA | IO phase: The phase delay of the IO signals | 1/64th DCK | [0-512) |
+---------+-------------------------------------------------------------------+------------+--------------+
| SPD | Manufacturer set memory timings located on an EEPROM on every DIMM| bytes | |
+---------+-------------------------------------------------------------------+------------+--------------+
| REFCK | Reference clock, either 100 or 133 | MHz | 100, 133 |
+---------+-------------------------------------------------------------------+------------+--------------+
| MULT | DRAM PLL multiplier | | [3-12] |
+---------+-------------------------------------------------------------------+------------+--------------+
| XMP | Extreme Memory Profiles | | |
+---------+-------------------------------------------------------------------+------------+--------------+
| DQS | Data Strobe signal used to sample all lane's DQ signals | | |
+---------+-------------------------------------------------------------------+------------+--------------+
```
## Hardware
The hardware does have delay logic blocks that can delay the DQ / DQS of a
lane/rank by one or multiple clock cylces and it does have delay logic blocks
that can delay the signal by a multiple of 1/64th DCK per lane.
All delay values can be controlled via software by writing registers in the
MCHBAR.
## IO phase
The IO phase can be adjusted in [0-512) * 1/64th DCK. Incrementing it by 64 is
the same as Incrementing IO delay by 1.
## IO delay
Delays the DQ / DQS signal by one or multiple clock cycles.
### Roundtrip time
The roundtrip time is the time the memory controller waits for data arraving
after a read has been issued. Due to clock-domain crossings, multiple
delay instances and phase interpolators, the signal runtime to DRAM and back
to memory controller defaults to 55 DCKs. The real roundtrip time has to be
measured.
After a read command has been issued, a counter counts down until zero has been
reached and activates the input buffers.
The following pictures shows the relationship between those three values.
The picture was generated from 16 IO delay values times 64 timA values.
The highest IO delay was set on the right-hand side, while the last block
on the left-hand side has zero IO delay.
#### roundtrip 55 DCKs
![alt text][timA_lane0-3_rt55]
[timA_lane0-3_rt55]: timA_lane0-3_rt55.png "timA for lane0 - lane3, roundtrip 55"
#### roundtrip 54 DCKs
![alt text][timA_lane0-3_rt54]
[timA_lane0-3_rt54]: timA_lane0-3_rt54.png "timA for lane0 - lane3, roundtrip 54"
#### roundtrip 53 DCKs
![alt text][timA_lane0-3_rt53]
[timA_lane0-3_rt53]: timA_lane0-3_rt53.png "timA for lane0 - lane3, roundtrip 53"
As you can see the signal has some jitter as every sample was taken in a
different loop iteration. The result register only contains a single bit per
lane.
## Algorithm
### Steps
The algorithm finds the roundtrip time, IO delay and IO phase. The IO phase
will be adjusted to match the falling edge of the preamble of each lane.
The roundtrip time is adjusted to an minimal value, that still includes the
preamble.
### Synchronize to data phase
The first measurement done in read-leveling samples all DQS values for one
phase [0-64) * 1/64th DCK. It then searches for the middle of the low data
symbol and adjusts timA to the found phase and thus the following measurements
will be aligned to the low data symbol.
The code assumes that the initial roundtrip time causes the measurement to be
in the alternating pattern data phase.
### Finding the preamble
After adjusting the IO phase to the middle of one data symbol the preamble will
be located. Unlike the data phase, which is an alternating pattern (010101...),
the preamble consists of two high data cycles.
The code decrements the IO delay/RTT and samples the DQS signal with timA
untouched. As it has been positioned in the middle of the data symbol, it'll
read as either "low" or "high".
If it's "low" we are still in the data phase.
If it's "high" we have found the preamble.
The roundtrip time and IO delay will be adjusted until all lanes are aligned.
The resulting IO delay is visible in the picture below.
** roundtrip time: 49 DCKs, IO delay (at blue point): 6 DCKs **
![alt text][timA_lane0-3_discover_420x]
[timA_lane0-3_discover_420x]: timA_lane0-3_discover_420x.png "timA for lane0 - lane3, finding minimum roundtrip time"
** Note: The sampled data has been shifted by timA. The preamble is now
in phase. **
## Fine adjustment
As timA still points the middle of the data symbol an offset of 32 is added.
It now points the falling edge of the preamble.
The fine adjustment is to reduce errors introduced by jitter. The phase is
adjusted from `timA - 25` to `timA + 25` and the DQS signal is sampled 100
times. The fine adjustment finds the middle of each rising edge (it's actual
the falling edge of the preamble) to get the final IO phase. You can see the
result in the picture below.
![alt text][timA_lane0-3_adjust_fine]
[timA_lane0-3_adjust_fine]: timA_lane0-3_adjust_fine.png "timA for lane0 - lane3, fine adjustment"
Lanes 0 - 2 will be adjusted by a phase of -10, while lane 3 is already correct.

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@@ -148,6 +148,7 @@ mv build/coreboot.rom.new build/coreboot.rom
<li>Edit the src/soc/&lt;Vendor&gt;/&lt;Chip Family&gt;/memmap.c file
<ol type="A">
<li>Add the fsp/memmap.h include file</li>
<li>Add the mmap_region_granularity routine</li>
</ol>
</li>
<li>Add the necessary .h files to define the necessary values and structures</li>
@@ -233,6 +234,8 @@ Use the following steps to locate the FSP binary:
<a target="_blank" href="https://review.coreboot.org/gitweb?p=coreboot.git;a=blob;f=src/drivers/intel/fsp1_1/cache_as_ram.inc">src/drivers/intel/fsp1_1/cache_as_ram.inc</a>
</li>
<li>Add "select SOC_INTEL_COMMON" to enable the use of the files from src/soc/intel/common
specifically building
<a target="_blank" href="https://review.coreboot.org/gitweb?p=coreboot.git;a=blob;f=src/soc/intel/common/util.c">util.c</a>
</li>
</ol>
</li>
@@ -513,7 +516,7 @@ Use the following steps to debug the call to TempRamInit:
a "struct pci_operations" that specifies a routine to set the subsystem
IDs for the device. The routine might look something like this:
</p>
<pre><code>static void pci_set_subsystem(struct device *dev, unsigned vendor, unsigned device)
<pre><code>static void pci_set_subsystem(device_t dev, unsigned vendor, unsigned device)
{
if (!vendor || !device) {
vendor = pci_read_config32(dev, PCI_VENDOR_ID);
@@ -535,7 +538,7 @@ Use the following steps to debug the call to TempRamInit:
The memory map is built by the various PCI device drivers during the
BS_DEV_RESOURCES state of ramstage. The northcluster driver will typically
specify the DRAM resources while the other drivers will typically specify
the IO resources. These resources are hung off the struct device *data structure by
the IO resources. These resources are hung off the device_t data structure by
src/device/device_util.c/<a target="_blank" href="https://review.coreboot.org/gitweb?p=coreboot.git;a=blob;f=src/device/device_util.c;hb=HEAD#l448">new_resource</a>.
</p>
<p>

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@@ -264,7 +264,7 @@
<ul>
<li>MemoryInit UPD values are correct</li>
<li>MemoryInit returns 0 (success) and</li>
<li>The message "ERROR - coreboot's requirements not met by FSP binary!"
<li>The the message "ERROR - coreboot's requirements not met by FSP binary!"
is not displayed
</li>
</ul>
@@ -324,7 +324,7 @@
<ul>
<li>MemoryInit UPD values are correct</li>
<li>MemoryInit returns 0 (success) and</li>
<li>The message "ERROR - coreboot's requirements not met by FSP binary!"
<li>The the message "ERROR - coreboot's requirements not met by FSP binary!"
is not displayed
</li>
</ul>
@@ -374,4 +374,4 @@
<hr>
<p>Modified: 4 March 2016</p>
</body>
</html>
</html>

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@@ -29,6 +29,7 @@
</li>
<li><a target="_blank" href="SoC/soc.html">SoC</a> support</li>
<li><a target="_blank" href="Board/board.html">Board</a> support</li>
<li><a target="_blank" href="vboot.html">Verified Boot (vboot)</a> support</li>
</ul>

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@@ -0,0 +1,402 @@
<!DOCTYPE html>
<html>
<head>
<title>vboot - Verified Boot Support</title>
</head>
<body>
<h1>vboot - Verified Boot Support</h1>
<p>
Google's verified boot support consists of:
</p>
<ul>
<li>A root of trust</li>
<li>Special firmware layout</li>
<li>Firmware verification</li>
<li>Firmware measurements</li>
<li>A firmware update mechanism</li>
<li>Specific build flags</li>
<li>Signing the coreboot image</li>
</ul>
Google's vboot verifies the firmware and places measurements
within the TPM.
<hr>
<h2>Root of Trust</h2>
<p>
When using vboot, the root-of-trust is basically the read-only portion of the
SPI flash. The following items factor into the trust equation:
</p>
<ul>
<li>The GCC compiler must reliably translate the code into machine code
without inserting any additional code (virus, backdoor, etc.)
</li>
<li>The CPU must reliably execute the reset sequence and instructions as
documented by the CPU manufacturer.
</li>
<li>The SPI flash must provide only the code programmed into it to the CPU
without providing any alternative reset vector or code sequence.
</li>
<li>The SPI flash must honor the write-protect input and protect the
specified portion of the SPI flash from all erase and write accesses.
</li>
</ul>
<p>
The firmware is typically protected using the write-protect pin on the SPI
flash part and setting some of the write-protect bits in the status register
during manufacturing. The protected area is platform specific and for x86
platforms is typically 1/4th of the SPI flash
part size. Because this portion of the SPI flash is hardware write protected,
it is not possible to update this portion of the SPI flash in the field,
without altering the system to eliminate the ground connection to the SPI flash
write-protect pin. Without hardware modifications, this portion of the SPI
flash maintains the manufactured state during the system's lifetime.
</p>
<hr>
<h2>Firmware Layout</h2>
<p>
Several sections are added to the firmware layout to support vboot:
</p>
<ul>
<li>Read-only section</li>
<li>Google Binary Blob (GBB) area</li>
<li>Read/write section A</li>
<li>Read/write section B</li>
</ul>
<p>
The following sections describe the various portions of the flash layout.
</p>
<h3>Read-Only Section</h3>
<p>
The read-only section contains a coreboot file system (CBFS) that contains all
of the boot firmware necessary to perform recovery for the system. This
firmware is typically protected using the write-protect pin on the SPI flash
part and setting some of the write-protect bits in the status register during
manufacturing. The protected area is typically 1/4th of the SPI flash part
size and must cover the entire read-only section which consists of:
</p>
<ul>
<li>Vital Product Data (VPD) area</li>
<li>Firmware ID area</li>
<li>Google Binary Blob (GBB) area</li>
<li>coreboot file system containing read-only recovery firmware</li>
</ul>
<h3>Google Binary Blob (GBB) Area</h3>
<p>
The GBB area is part of the read-only section. This area contains a 4096 or
8192 bit public root RSA key that is used to verify the VBLOCK area to obtain
the firmware signing key.
</p>
<h3>Recovery Firmware</h3>
<p>
The recovery firmware is contained within a coreboot file system and consists
of:
</p>
<ul>
<li>reset vector</li>
<li>bootblock</li>
<li>verstage</li>
<li>romstage</li>
<li>postcar</li>
<li>ramstage</li>
<li>payload</li>
<li>flash map file</li>
<li>config file</li>
<li>processor specific files:
<ul>
<li>Microcode</li>
<li>fspm.bin</li>
<li>fsps.bin</li>
</ul>
</li>
</ul>
<p>
The recovery firmware is written during manufacturing and typically contains
code to write the storage device (eMMC device or hard disk). The recovery
image is usually contained on a socketed device such as a USB flash drive or
an SD card. Depending upon the payload firmware doing the recovery, it may
be possible for the user to interact with the system to specify the recovery
image path. Part of the recovery is also to write the A and B areas of the
SPI flash device to boot the system.
</p>
<h3>Read/Write Section</h3>
<p>
The read/write sections contain an area which contains the firmware signing
key and signature and an area containing a coreboot file system with a subset
of the firmware. The firmware files in FW_MAIN_A and FW_MAIN_B are:
</p>
<ul>
<li>romstage</li>
<li>postcar</li>
<li>ramstage</li>
<li>payload</li>
<li>config file</li>
<li>processor specific files:
<ul>
<li>Microcode</li>
<li>fspm.bin</li>
<li>fsps.bin</li>
</ul>
</li>
</ul>
<p>
The firmware subset enables most issues to be fixed in the field with firmware
updates. The firmware files handle memory and most of silicon initialization.
These files also produce the tables which get passed to the operating system.
</p>
<hr>
<h2>Firmware Updates</h2>
<p>
The read/write sections exist in one of three states:
</p>
<ul>
<li>Invalid</li>
<li>Ready to boot</li>
<li>Successfully booted</li>
</ul>
<table border="1">
<tr bgcolor="#ffc0c0">
<td>
Where is this state information written?
<br/>CMOS?
<br/>RW_NVRAM?
<br/>RW_FWID_*
</td>
</tr>
</table>
<p>
Firmware updates are handled by the operating system by writing any read/write
section that is not in the "successfully booted" state. Upon the next reboot,
vboot determines the section to boot. If it finds one in the "ready to boot"
state then it attempts to boot using that section. If the boot fails then
vboot marks the section as invalid and attempts to fall back to a read/write
section in the "successfully booted" state. If vboot is not able to find a
section in the "successfully booted" state then vboot enters recovery mode.
</p>
<p>
Only the operating system is able to transition a section from the "ready to
boot" state to the "successfully booted" state. The transition is typically
done after the operating system has been running for a while indicating
that successful boot was possible and the operating system is stable.
</p>
<p>
Note that as long as the SPI write protection is in place then the system is
always recoverable. If the flash update fails then the system will continue
to boot using the previous read/write area. The same is true if coreboot
passes control to the payload or the operating system and then the boot fails.
In the worst case, the SPI flash gets totally corrupted in which case vboot
fails the signature checks and enters recovery mode. There are no times where
the SPI flash is exposed and the reset vector or part of the recovery firmware
gets corrupted.
</p>
<hr>
<h2>Build Flags</h2>
<p>
The following Kconfig values need to be selected to enable vboot:
</p>
<ul>
<li>COLLECT_TIMESTAMPS</li>
<li>VBOOT</li>
</ul>
<p>
The starting stage needs to be specified by selecting either
VBOOT_STARTS_IN_BOOTBLOCK or VBOOT_STARTS_IN_ROMSTAGE.
</p>
<p>
If vboot starts in bootblock then vboot may be built as a separate stage by
selecting VBOOT_SEPARATE_VERSTAGE. Additionally, if static RAM is too small
to fit both verstage and romstage then selecting VBOOT_RETURN_FROM_VERSTAGE
enables bootblock to reuse the RAM occupied by verstage for romstage.
</p>
<p>
Non-volatile flash is needed for vboot operation. This flash area may be in
CMOS, the EC, or in a read/write area of the SPI flash device. Select one of
the following:
</p>
<ul>
<li>VBOOT_VBNV_CMOS</li>
<li>VBOOT_VBNV_EC</li>
<li>VBOOT_VBNV_FLASH</li>
</ul>
<p>
More non-volatile storage features may be found in src/vboot/Kconfig.
</p>
<p>
A TPM is also required for vboot operation. TPMs are available in
drivers/i2c/tpm and drivers/pc80/tpm.
</p>
<p>
In addition to adding the coreboot files into the read-only region, enabling
vboot causes the build script to add the read/write files into coreboot file
systems in FW_MAIN_A and FW_MAIN_B.
</p>
<hr>
<h2>Signing the coreboot Image</h2>
<p>
The following command script is an example of how to sign the coreboot image file.
This script is used on the Intel Galileo board and creates the GBB area and
inserts it into the coreboot image. It also updates the VBLOCK areas with the
firmware signing key and the signature for the FW_MAIN firmware. More details
are available in 3rdparty/vboot/README.
</p>
<pre><code>#!/bin/sh
#
# The necessary tools were built and installed using the following commands:
#
# pushd 3rdparty/vboot
# make
# sudo make install
# popd
#
# The keys were made using the following command
#
# 3rdparty/vboot/scripts/keygeneration/create_new_keys.sh \
# --4k --4k-root --output $PWD/keys
#
#
# The "magic" numbers below are derived from the GBB section in
# src/mainboard/intel/galileo/vboot.fmd.
#
# GBB Header Size: 0x80
# GBB Offset: 0x611000, 4KiB block number: 1553 (0x611)
# GBB Length: 0x7f000, 4KiB blocks: 127 (0x7f)
# COREBOOT Offset: 0x690000, 4KiB block number: 1680 (0x690)
# COREBOOT Length: 0x170000, 4KiB blocks: 368 (0x170)
#
# 0x7f000 (GBB Length) = 0x80 + 0x100 + 0x1000 + 0x7ce80 + 0x1000
#
# Create the GBB area blob
# Parameters: hwid_size,rootkey_size,bmpfv_size,recoverykey_size
#
gbb_utility -c 0x100,0x1000,0x7ce80,0x1000 gbb.blob
#
# Copy from the start of the flash to the GBB region into the signed flash
# image.
#
# 1553 * 4096 = 0x611 * 0x1000 = 0x611000, size of area before GBB
#
dd conv=fdatasync ibs=4096 obs=4096 count=1553 \
if=build/coreboot.rom of=build/coreboot.signed.rom
#
# Append the empty GBB area to the coreboot.rom image.
#
# 1553 * 4096 = 0x611 * 0x1000 = 0x611000, offset to GBB
#
dd conv=fdatasync obs=4096 obs=4096 seek=1553 if=gbb.blob \
of=build/coreboot.signed.rom
#
# Append the rest of the read-only region into the signed flash image.
#
# 1680 * 4096 = 0x690 * 0x1000 = 0x690000, offset to COREBOOT area
# 368 * 4096 = 0x170 * 0x1000 = 0x170000, length of COREBOOT area
#
dd conv=fdatasync ibs=4096 obs=4096 skip=1680 seek=1680 count=368 \
if=build/coreboot.rom of=build/coreboot.signed.rom
#
# Insert the HWID and public root and recovery RSA keys into the GBB area.
#
gbb_utility \
--set --hwid='Galileo' \
-r $PWD/keys/recovery_key.vbpubk \
-k $PWD/keys/root_key.vbpubk \
build/coreboot.signed.rom
#
# Sign the read/write firmware areas with the private signing key and update
# the VBLOCK_A and VBLOCK_B regions.
#
3rdparty/vboot/scripts/image_signing/sign_firmware.sh \
build/coreboot.signed.rom \
$PWD/keys \
build/coreboot.signed.rom
</code></pre>
<hr>
<h2>Boot Flow</h2>
<p>
The reset vector exist in the read-only area and points to the bootblock entry
point. The only copy of the bootblock exists in the read-only area of the SPI
flash. Verstage may be part of the bootblock or a separate stage. If separate
then the bootblock loads verstage from the read-only area and transfers control
to it.
</p>
<p>
Upon first boot, verstage attempts to verify the read/write section A. It gets
the public root key from the GBB area and uses that to verify the VBLOCK area
in read-write section A. If the VBLOCK area is valid then it extracts the
firmware signing key (1024-8192 bits) and uses that to verify the FW_MAIN_A
area of read/write section A. If the verification is successful then verstage
instructs coreboot to use the coreboot file system in read/write section A for
the contents of the remaining boot firmware (romstage, postcar, ramstage and
the payload).
</p>
<p>
If verification fails for the read/write area and the other read/write area is
not valid vboot falls back to the read-only area to boot into system recovery.
</p>
<hr>
<h2>Chromebook Special Features</h2>
<p>
Google's Chromebooks have some special features:
</p>
<ul>
<li>Developer mode</li>
<li>Write-protect screw</li>
</ul>
<h3>Developer Mode</h3>
<p>
Developer mode allows the user to use coreboot to boot another operating system.
This may be a another (beta) version of Chrome OS, or another flavor of
GNU/Linux. Use of developer mode does not void the system warranty. Upon
entry into developer mode, all locally saved data on the system is lost.
This prevents someone from entering developer mode to subvert the system
security to access files on the local system or cloud.
</p>
<h3>Write Protect Screw</h3>
<p>
Chromebooks have a write-protect screw which provides the ground to the
write-protect pin of the SPI flash. Google specifically did this to allow
the manufacturing line and advanced developers to re-write the entire SPI flash
part. Once the screw is removed, any firmware may be placed on the device.
However, accessing this screw requires opening the case and voids the system
warranty!
</p>
<hr>
<p>Modified: 2 May 2017</p>
</body>
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\documentclass[10pt,letterpaper]{article}
\usepackage[latin1]{inputenc}
\usepackage{amsmath}
\usepackage{amsfonts}
\usepackage{amssymb}
\author{Ron Minnich}
\title{Kconfig usage in coreboot v2}
\begin{document}
\section{Introduction}
This document describes how to use Kconfig in v2. We describe our usage of Kconfig files, Makefile.inc files, when and where to use them, how to use them, and, interestingly, when and where not to use them.
\section{Kconfig variations}
Most Kconfig files set variables, which can be set as part of the Kconfig dialog. Not all Kconfig variables are set by the user, however; some are too dangerous. These are merely enabled by the mainboard.
For variables set by the user, see src/console/Kconfig.
For variables not set by the user, see src/mainboard/amd/serengeti\_cheetah/Kconfig. Users should never set such variables as the cache as RAM base. These are highly mainboard dependent.
Kconfig files use the source command to include subdirectories. In most cases, save for limited cases described below, subdirectories have Kconfig files. They are always sourced unconditionally.
\section{Makefile and Makefile.inc}
There is only one Makefile, at the top level. All other makefiles are included as Makefile.inc. All the next-level Makefile.inc files are selected in the top level Makefile. Directories that are platform-independent are in BUILD-y; platform-dependent (e.g. Makefile.inc's that depend on architecture) are included in PLATFORM-y.
Make is not recursive. There is only one make process.
\subsection{subdirs usage}
Further includes of Makefile.inc, if needed, are done via subdirs-y commands. As in Linux, the subdirs can be conditional or unconditional. Conditional includes are done via subdirs-\$(CONFIG\_VARIABLE) usage; unconditional are done via subdirs-y.
We define the common rules for which variation to use below.
\subsection{object file specification}
There are several different types of objects specified in the tree. They are:
\begin{description}
\item[obj]objects for the RAM part of the code
\item[driver]drivers for the RAM part. Drivers are not represented in the device tree but do have a driver struct attached in the driver section.
\item[initobj]seperately-compiled code for the ROM section of coreboot
\end{description}
These items are specified via the -y syntax as well. Conditional object inclusion is done via the -\$(CONFIG\_VARIABLE) syntax.
\section{Example: AMD serengeti cheetah}
\subsection{mainboard/Kconfig}
Defines Vendor variables. Currently defined variables are:
Sources all Kconfig files in the vendor directories.
\input{ mainboardkconfig.tex}
\subsection{mainboard/Makefile.inc}
There is none at this time.
\subsection{mainboard/$<$vendor$>$/Kconfig}
We use the amd as a model. The only action currently taken is to source all Kconfig's in the
subdirectories.
\subsection{mainboard/$<$vendor$>$/Makefile.inc}
We use amd as a model. There is currently no Makefile.inc at this level.
\subsection{mainboard/$<$vendor$>$/$<$board$>$/Kconfig}
The mainboard Kconfig and Makefile.inc are designed to be the heart of the build. The defines
and rules in here determine everything about how a mainboard target is built.
We will use serengeti\_cheetah as a model. It defines these variables.
\input{ mainboardkconfig.tex}
\subsection{mainboard/$<$vendor$>$/$<$board$>$/Makefile.inc}
This is a fairly complex Makefile.inc. Because this is such a critical component, we are going to excerpt and take it piece by piece.
Note that this is the mainboard as of August, 2009, and it may change over time.
\subsubsection{objects}
We define objects in the first part. The mainbard itself is a driver and included unconditionally. Other objects are conditional:
\begin{verbatim}
driver-y += mainboard.o
#needed by irq_tables and mptable and acpi_tables
obj-y += get_bus_conf.o
obj-$(CONFIG_HAVE_MP_TABLE) += mptable.o
obj-$(CONFIG_HAVE_PIRQ_TABLE) += irq_tables.o
obj-$(CONFIG_HAVE_ACPI_TABLES) += dsdt.o
obj-$(CONFIG_HAVE_ACPI_TABLES) += acpi_tables.o
obj-$(CONFIG_HAVE_ACPI_TABLES) += fadt.o
#./ssdt.o is in northbridge/amd/amdk8/Config.lb
obj-$(CONFIG_ACPI_SSDTX_NUM) += ssdt2.o
obj-$(CONFIG_ACPI_SSDTX_NUM) += ssdt3.o
obj-$(CONFIG_HAVE_ACPI_TABLES) += ssdt4.o
driver-y += ../../../drivers/i2c/i2cmux/i2cmux.o
# This is part of the conversion to init-obj and away from included code.
initobj-y += crt0.o
\end{verbatim}
\subsubsection{romcc legacy support}
We hope to move away from romcc soon, but for now, if one is using romcc, the Makefile.inc must define
crt0 include files (assembly code for startup, usually); and several ldscripts. These are taken directly from the
old Config.lb. Note that these use the -y syntax and can use the ability to be included conditionally.
\begin{verbatim}
crt0-y += ../../../../src/cpu/x86/16bit/entry16.inc
crt0-y += ../../../../src/cpu/x86/32bit/entry32.inc
crt0-y += ../../../../src/cpu/x86/16bit/reset16.inc
crt0-y += ../../../../src/arch/i386/lib/id.inc
crt0-y += ../../../../src/cpu/amd/car/cache_as_ram.inc
crt0-y += auto.inc
ldscript-y += ../../../../src/arch/i386/init/ldscript_fallback_cbfs.lb
ldscript-y += ../../../../src/cpu/x86/16bit/entry16.lds
ldscript-y += ../../../../src/cpu/x86/16bit/reset16.lds
ldscript-y += ../../../../src/arch/i386/lib/id.lds
ldscript-y += ../../../../src/arch/i386/lib/failover.lds
\end{verbatim}
\subsubsection{POST\_EVALUATION}
POST\_EVALUATION rules should be placed after this section:
\begin{verbatim}
ifdef POST_EVALUATION
\end{verbatim}
to ensure that the values of variables are correct.
Here are the post-evaluation rules for this mainboard:
\begin{verbatim}
$(obj)/dsdt.c: $(src)/mainboard/$(MAINBOARDDIR)/dsdt.asl
iasl -p dsdt -tc $(src)/mainboard/$(MAINBOARDDIR)/dsdt.asl
mv dsdt.hex $@
$(obj)/mainboard/$(MAINBOARDDIR)/dsdt.o: $(obj)/dsdt.c
$(CC) $(DISTRO_CFLAGS) $(CFLAGS) $(CPPFLAGS) $(DEBUG_CFLAGS) -I$(src) -I. -c $< -o $@
$(obj)/ssdt2.c: $(src)/mainboard/$(MAINBOARDDIR)/dx/pci2.asl
iasl -p $(CURDIR)/pci2 -tc $(CONFIG_MAINBOARD)/dx/pci2.asl
perl -pi -e 's/AmlCode/AmlCode_ssdt2/g' pci2.hex
mv pci2.hex ssdt2.c
$(obj)/ssdt3.c: $(src)/mainboard/$(MAINBOARDDIR)/dx/pci3.asl"
iasl -p $(CURDIR)/pci3 -tc $(CONFIG_MAINBOARD)/
perl -pi -e 's/AmlCode/AmlCode_ssdt3/g' pci3.hex
mv pci3.hex ssdt3.c
$(obj)/ssdt4.c: $(src)/mainboard/$(MAINBOARDDIR)/dx/pci4.asl"
iasl -p $(CURDIR)/pci4 -tc $(CONFIG_MAINBOARD)/dx/pci4.asl
perl -pi -e 's/AmlCode/AmlCode_ssdt4/g' pci4.hex
mv pci4.hex ssdt4.c
$(obj)/mainboard/$(MAINBOARDDIR)/auto.inc: $(src)/mainboard/$(MAINBOARDDIR)/rom.c $(obj)/option_table.h
$(CC) $(DISTRO_CFLAGS) $(CFLAGS) $(CPPFLAGS) $(DEBUG_CFLAGS) -I$(src) -I. -c -S $(src)/mainboard/$(MAINBOARDDIR)/rom.c -o $@
perl -e 's/\.rodata/.rom.data/g' -pi $@
perl -e 's/\.text/.section .rom.text/g' -pi $@
\end{verbatim}
The last rule is for romcc, and, again, we hope to eliminate romcc usage and this rule soon. The first set of rules concern ACPI tables.
\subsubsection{devicetree.cb}
Most of the old Config.lb is gone, but one piece remains: the device tree specification. This tree is still required to build a mainboard
properly, as it defines topology and chips that can be defined no other way.
Let's go through the tree.
\begin{verbatim}
chip northbridge/amd/amdk8/root_complex
device cpu_cluster 0 on
chip cpu/amd/socket_F
device lapic 0 on end
end
end
\end{verbatim}
This topology is always somewhat confusing to newcomers, and even to coreboot veterans.
We root the tree at the pci-e {\it root complex}. There is always the question of how and where to root the tree. Over the years we
have found that the one part that never goes away is the root complex. CPU sockets may be empty or full; but there is always a northbridge
somewhere, since it runs memory.
What is the APIC? Northbridges always have an Advanced Programmable Interrupt Controller, and that {\it APIC cluster} is a topological connection to the
CPU socket. So the tree is rooted at the northbridge, which has a link to a CPU cluster, and then the CPU. The CPU contains
its own APIC, and will define any parameters needed. In this case, we have a northbridge of type
{\it northbridge/amd/amdk8/root\_complex}, with its own cpu\_cluster device which we turn on,
which connects to a {\it cpu/amd/socket\_F},
which has a local apic, which is on.
Note that we do not enumerate all CPUs, even on this SMP mainboard. The reason is they may not all be there. The CPU we define here
is the so-called Boot Strap Processor, or BSP; the other CPUs will come along later, as the are discovered. We do not require (unlike many
BIOSes) that the BSP be CPU 0; any CPU will do.
\begin{verbatim}
device domain 0 on
chip northbridge/amd/amdk8
device pci 18.0 on # northbridge
# devices on link 0, link 0 == LDT 0
\end{verbatim}
Here begins the pci domain, which usually starts with 0. Then there is the northbridge, which bridges to the PCI bus. On
Opterons, certain CPU control registers are managed in PCI config space in device 18.0 (BSP), 19.0 (AP), and up.
\begin{verbatim}
chip southbridge/amd/amd8132
# the on/off keyword is mandatory
device pci 0.0 on end
device pci 0.1 on end
device pci 1.0 on end
device pci 1.1 on end
end
\end{verbatim}
This is the 8132, a bridge to a secondary PCI bus.
\begin{verbatim}
chip southbridge/amd/amd8111
# this "device pci 0.0" is the parent the next one
# PCI bridge
device pci 0.0 on
device pci 0.0 on end
device pci 0.1 on end
device pci 0.2 off end
device pci 1.0 off end
end
\end{verbatim}
The 8111 is a bridge to other busses and to the legacy ISA devices such as superio.
\begin{verbatim}
device pci 1.0 on
chip superio/winbond/w83627hf
device pnp 2e.0 off # Floppy
io 0x60 = 0x3f0
irq 0x70 = 6
drq 0x74 = 2
end
device pnp 2e.1 off # Parallel Port
io 0x60 = 0x378
irq 0x70 = 7
end
device pnp 2e.2 on # Com1
io 0x60 = 0x3f8
irq 0x70 = 4
end
device pnp 2e.3 off # Com2
io 0x60 = 0x2f8
irq 0x70 = 3
end
device pnp 2e.5 on # Keyboard
io 0x60 = 0x60
io 0x62 = 0x64
irq 0x70 = 1
irq 0x72 = 12
end
device pnp 2e.6 off # CIR
io 0x60 = 0x100
end
device pnp 2e.7 off # GAME_MIDI_GIPO1
io 0x60 = 0x220
io 0x62 = 0x300
irq 0x70 = 9
end
device pnp 2e.8 off end # GPIO2
device pnp 2e.9 off end # GPIO3
device pnp 2e.a off end # ACPI
device pnp 2e.b on # HW Monitor
io 0x60 = 0x290
irq 0x70 = 5
end
end
end
\end{verbatim}
The pnp refers to the many Plug N Play devices on a superio. 2e refers to the base I/O address of the superio, and the number following the
2e (i.e. 2e.1) is the Logical Device Number, or LDN. Each LDN has a common configuration (base, irq, etc.) and these are set by the statements under the LDN.
\begin{verbatim}
device pci 1.1 on end
device pci 1.2 on end
\end{verbatim}
More devices. These statements set up placeholders in the device tree.
\begin{verbatim}
device pci 1.3 on
chip drivers/i2c/i2cmux # pca9556 smbus mux
device i2c 18 on #0 pca9516 1
chip drivers/generic/generic #dimm 0-0-0
device i2c 50 on end
end
chip drivers/generic/generic #dimm 0-0-1
device i2c 51 on end
end
chip drivers/generic/generic #dimm 0-1-0
device i2c 52 on end
end
chip drivers/generic/generic #dimm 0-1-1
device i2c 53 on end
end
end
device i2c 18 on #1 pca9516 2
chip drivers/generic/generic #dimm 1-0-0
device i2c 50 on end
end
chip drivers/generic/generic #dimm 1-0-1
device i2c 51 on end
end
chip drivers/generic/generic #dimm 1-1-0
device i2c 52 on end
end
chip drivers/generic/generic #dimm 1-1-1
device i2c 53 on end
end
chip drivers/generic/generic #dimm 1-2-0
device i2c 54 on end
end
chip drivers/generic/generic #dimm 1-2-1
device i2c 55 on end
end
chip drivers/generic/generic #dimm 1-3-0
device i2c 56 on end
end
chip drivers/generic/generic #dimm 1-3-1
device i2c 57 on end
end
end
end
end # acpi
\end{verbatim}
These are the i2c devices.
\begin{verbatim}
device pci 1.5 off end
device pci 1.6 off end
\end{verbatim}
More placeholders.
\begin{verbatim}
register "ide0_enable" = "1"
register "ide1_enable" = "1"
end
end # device pci 18.0
\end{verbatim}
These "register" commands set controls in the southbridge.
\begin{verbatim}
device pci 18.0 on end
device pci 18.0 on end
\end{verbatim}
These are the other two hypertransport links.
\begin{verbatim}
device pci 18.1 on end
device pci 18.2 on end
device pci 18.3 on end
\end{verbatim}
The 18.1 devices are, again, northbridge control for various k8 functions.
\begin{verbatim}
end
\end{verbatim}
That's it for the BSP I/O and HT busses. Now we begin the AP busses. Not much here.
\begin{verbatim}
chip northbridge/amd/amdk8
device pci 19.0 on # northbridge
chip southbridge/amd/amd8151
# the on/off keyword is mandatory
device pci 0.0 on end
device pci 1.0 on end
end
end # device pci 19.0
device pci 19.0 on end
device pci 19.0 on end
device pci 19.1 on end
device pci 19.2 on end
device pci 19.3 on end
end
\end{verbatim}
\subsection{cpu socket}
The CPU socket is the key link from mainboard to its CPUs. Since many models of CPU can go in a socket, the mainboard mentions only
the socket, and the socket, in turn, references the various model CPUs which can be plugged into it. The socket is thus the focus
of all defines and Makefile controls for building the CPU components of a board.
\subsubsection{ cpu/Kconfig}
Defines variables. Current variables are:
\input{cpukconfig.tex}
Sources all Kconfig files in the vendor directories.
\subsubsection{ cpu/Makefile.inc}
Unconditionally sources all Makefile.inc in the vendor directories.
\subsection{cpu/$<$vendor$>$/Kconfig}
The only action currently taken is to source all Kconfig's in the
subdirectories.
\subsection{cpu/$<$vendor$>$/Makefile.inc}
{\em Conditionally} source the socket directories.
Example:
\begin{verbatim}
subdirs-$(CONFIG_CPU_AMD_SOCKET_F) += socket_F
\end{verbatim}
.
CONFIG\_CPU\_AMD\_SOCKET\_F is set in a mainboard file.
\subsection{cpu/$<$vendor$>$/$<$socket$>$/Kconfig}
Set variables that relate to this {\em socket}, and {\em any models that plug into this socket}. Note that
the socket, as much as possible, should control the models, because the models may plug into many sockets.
Socket\_F currently sets:
\input{socketfkconfig.tex}
It sources only those Kconfigs that relate to this particular socket, i.e. not all possible models are sourced.
\subsection{cpu/$<$vendor$>$/$<$model$>$/Kconfig}
CPU Model Kconfigs only set variables, We do not expect that they will source any other Kconfig. The socket Kconfig should do that
if needed.
\subsection{cpu/$<$vendor$>$/$<$model$>$/Makefile.inc}
The Makefile.inc {\em unconditionally} specifies drivers and objects to be included in the build. There is no conditional
compilation at this point. IF a socket is included, it includes the models. If a model is included, it should include {em all}
objects, because it is not possible to determine at build time what options may be needed for a given model CPU.
This Makefile.inc includes no other Makefile.inc files; any inclusion should be done in the socket Makefile.inc.
\subsection{northbridge}
\subsubsection{northbridge/Kconfig}
No variables. Source all vendor directory Kconfigs.
\subsubsection{northbridge/Makefile.inc}
No variables. unconditionally include all vendor Makefile.inc
\subsubsection{northbridge/$<$vendor$>$/Kconfig}
No variables. Source all chip directory Kconfigs.
\subsubsection{northbridge/$<$vendor$>$/Makefile.inc}
No variables. {\em Conditionally} include all chipset Makefile.inc. The variable
is the name of the part, e.g.
\begin{verbatim}
subdirs-$(CONFIG_NORTHBRIDGE_AMD_AMDK8) += amdk8
\end{verbatim}
.
\subsubsection{northbridge/$<$vendor$>$/$<$chip$>$/Kconfig}
Typically a small number of variables. One defines the part name. Here is an example
of the variables defined for the K8.
\begin{verbatim}
config NORTHBRIDGE_AMD_AMDK8
bool
default n
config AGP_APERTURE_SIZE
hex
default 0x4000000
\end{verbatim}
\subsubsection{northbridge/$<$vendor$>$/$<$chip$>$/Makefile.inc}
Typically very small set of rules, and very simple.
Since this file is already conditionally included,
we don't need to test for the chipset CONFIG variable. We
can therefore test other variables (which is part of the reason
we set up conditional inclusion of this file, instead
of unconditionally including it). Here is an example from AMD K8.
Note that we can make a variable conditional on the ACPI tables.
\begin{verbatim}
driver-y += northbridge.o
driver-y += misc_control.o
obj-y += get_sblk_pci1234.o
obj-$(CONFIG_HAVE_ACPI_TABLES) += amdk8_acpi.o
\end{verbatim}
\subsection{southbridge}
\subsubsection{southbridge/Kconfig}
No variables. Source all vendor directory Kconfigs.
\subsubsection{southbridge/Makefile.inc}
No variables. {\em Unconditionally} include all vendor Makefile.inc
\subsubsection{southbridge/$<$vendor$>$/Kconfig}
No variables. Source all chip directory Kconfigs.
\subsubsection{southbridge/$<$vendor$>$/Makefile.inc}
No variables. {\em Conditionally} include all chipset Makefile.inc. The variable
is the name of the part, e.g.
\begin{verbatim}
subdirs-$(CONFIG_SOUTHBRIDGE_AMD_AMD8111) += amd8111
\end{verbatim}
.
\subsubsection{southbridge/$<$vendor$>$/$<$chip$>$/Kconfig}
Typically a small number of variables. One defines the part name. Here is an example
of the variables defined for the K8.
\begin{verbatim}
config SOUTHBRIDGE_AMD_AMD8111
bool
default n
\end{verbatim}
\subsubsection{southbridge/$<$vendor$>$/$<$chip$>$/Makefile.inc}
Typically very small set of rules, and very simple.
Since this file is already conditionally included,
we don't need to test for the chipset CONFIG variable. We
can therefore test other variables (which is part of the reason
we set up conditional inclusion of this file, instead
of unconditionally including it). Here is an example from AMD 8111.
No conditionals in this one yet.
\begin{verbatim}
driver-y += amd8111.o
driver-y += amd8111_usb.o
driver-y += amd8111_lpc.o
driver-y += amd8111_ide.o
driver-y += amd8111_acpi.o
driver-y += amd8111_usb2.o
driver-y += amd8111_ac97.o
driver-y += amd8111_nic.o
driver-y += amd8111_pci.o
driver-y += amd8111_smbus.o
obj-y += amd8111_reset.o
\end{verbatim}
\subsubsection{vendor and part}
\subsection{southbridge}
\subsubsection{vendor and part}
\subsection{superio}
\subsection{drivers/i2c}
This is a rather special case. There are no Kconfig files or Makefile.inc files here. They are not needed.
To compile in one of these files, name the .o directory. E.g. in serengeti\_cheetah we have:
\begin{verbatim}
\end{verbatim}
\subsubsection{vendor and part}
\end{document}

281
Documentation/Lesson2.md Normal file
View File

@@ -0,0 +1,281 @@
# coreboot Lesson 2: Submitting a patch to coreboot.org
## Part 1: Setting up an account at coreboot.org
If you already have an account, skip to Part 2.
Otherwise, go to <https://review.coreboot.org> in your preferred web browser.
Select **Register** in the upper right corner.
Select the appropriate sign-in. For example, if you have a Google account,
select **Google OAuth2** (gerrit-oauth-provider plugin)".**Note:** Your
username for the account will be the username of the account you used to
sign-in with. (ex. your Google username).
## Part 2a: Set up RSA Private/Public Key
If you prefer to use an HTTP password instead, skip to Part 2b.
For the most up-to-date instructions on how to set up SSH keys with Gerrit go to
<https://gerrit-documentation.storage.googleapis.com/Documentation/2.14.2/user-upload.html#configure_ssh)>
and follow the instructions there. Then, skip to Part 3.
Additionally, that section of the Web site provides explanation on starting
an ssh-agent, which may be particularly helpful for those who anticipate
frequently uploading changes.
If you instead prefer to have review.coreboot.org specific instructions,
follow the steps below. Note that this particular section may have the
most up-to-date instructions.
If you do not have an RSA key set up on your account already (as is the case
with a newly created account), follow the instructions below; otherwise,
doing so could overwrite an existing key.
In the upper right corner, select your name and click on **Settings**.
Select **SSH Public Keys** on the left-hand side.
In a terminal, run "ssh-keygen" and confirm the default path ".ssh/id_rsa".
Make a passphrase -- remember this phrase. It will be needed whenever you use
this RSA Public Key. **Note:** You might want to use a short password, or
forego the password altogether as you will be using it very often.
Open "id_rsa.pub", copy all contents and paste into the textbox under
"Add SSH Public Key" in the https://review.coreboot.org webpage.
## Part 2b: Setting up an HTTP Password
Alternatively, instead of using SSH keys, you can use an HTTP password. To do so,
after you select your name and click on **Settings** on the left-hand side, rather
than selecting **SSH Public Keys**, select **HTTP Password**.
Click **Generate Password**. This should fill the "Password" box with a password. Copy
the password, and add the following to your $HOME/.netrc file:
machine review.coreboot.org login YourUserNameHere password YourPasswordHere
where YourUserNameHere is your username, and YourPasswordHere is the password you
just generated.
## Part 3: Clone coreboot and configure it for submitting patches
Go to the **Projects** tab in the upper left corner and select **List**.
From the dropdown menu that appears, select "coreboot".
If you are using SSH keys, select **ssh** from the tabs under "Project coreboot"
and run the command that appears. This should prompt you for your id_rsa passphrase,
if you previously set one.
If you are using HTTP, instead, select **http** from the tabs under "Project coreboot"
and run the command that appears
After it finishes cloning, "cd coreboot" will take you into the local
git repository. Run "make gitconfig" to set up the hooks and configurations.
For example, you will be asked to run the following commands to set your
username and email.
git config --global user.name "Your Name"
git config --global user.email "Your Email"
## Part 4: Submit a commit
An easy first commit to make is fixing existing checkpatch errors and warnings
in the source files. To see errors that are already present, build the files in
the repository by running 'make lint' in the coreboot directory. Alternatively,
if you want to run 'make lint' on a specific directory, run:
for file in $(git ls-files | grep src/amd/quadcore); do \
util/lint/checkpatch.pl --file $file --terse; done
where <filepath> is the filepath of the directory (ex. src/cpu/amd/car).
Any changes made to files under the src directory are made locally,
and can be submitted for review.
Once you finish making your desired changes, use the command line to stage
and submit your changes. An alternative and potentially easier way to stage
and submit commits is to use git cola, a graphical user interface for git. For
instructions on how to do so, skip to Part 4b.
## Part 4a: Using the command line to stage and submit a commit
To use the command line to stage a commit, run
git add <filename>
where `filename` is the name of your file.
To commit the change, run
git commit -s
**Note:** The -s adds a signed-off-by line by the committer. Your commit should be
signed off with your name and email (i.e. **Your Name** **<Your Email>**, based on
what you set with git config earlier).
Running git commit first checks for any errors and warnings using lint. If
there are any, you must go back and fix them before submitting your commit.
You can do so by making the necessary changes, and then staging your commit again.
When there are no errors or warnings, your default text editor will open.
This is where you will write your commit message.
The first line of your commit message is your commit summary. This is a brief
one-line description of what you changed in the files using the template
below:
<filepath>: Short description
*ex. cpu/amd/pi/00630F01: Fix checkpatch warnings and errors*
**Note:** It is good practice to use present tense in your descriptions
and do not punctuate your summary.
Then hit Enter. The next paragraph should be a more in-depth explanation of the
changes you've made to the files. Again, it is good practice to use present
tense.
*ex. Fix space prohibited between function name and open parenthesis,
line over 80 characters, unnecessary braces for single statement blocks,
space required before open brace errors and warnings.*
When you have finished writing your commit message, save and exit the text
editor. You have finished committing your change. If, after submitting your
commit, you wish to make changes to it, running "git commit --amend" allows
you to take back your commit and amend it.
When you are done with your commit, run 'git push' to push your commit to
coreboot.org. **Note:** To submit as a draft, use
'git push origin HEAD:refs/drafts/master' Submitting as a draft means that
your commit will be on coreboot.org, but is only visible to those you add
as reviewers.
## Part 4b: Using git cola to stage and submit a commit
If git cola is not installed on your machine, see
https://git-cola.github.io/downloads.html for download instructions.
After making some edits to src files, rather than run "git add," run
'git cola' from the command line. You should see all of the files
edited under "Modified".
In the textbox labeled "Commit summary" provide a brief one-line
description of what you changed in the files according to the template
below:
<filepath>: Short description
*ex. cpu/amd/pi/00630F01: Fix checkpatch warnings and errors*
**Note:** It is good practice to use present tense in your descriptions
and do not punctuate your short description.
In the larger text box labeled 'Extended description...' provide a more
in-depth explanation of the changes you've made to the files. Again, it
is good practice to use present tense.
*ex. Fix space prohibited between function name and open parenthesis,
line over 80 characters, unnecessary braces for single statement blocks,
space required before open brace errors and warnings.*
Then press Enter two times to move the cursor to below your description.
To the left of the text boxes, there is an icon with an downward arrow.
Press the arrow and select "Sign Off." Make sure that you are signing off
with your name and email (i.e. **Your Name** **<Your Email>**, based on what
you set with git config earlier).
Now, review each of your changes and mark either individual changes or
an entire file as Ready to Commit by marking it as 'Staged'. To do
this, select one file from the 'Modified' list. If you only want to
submit particular changes from each file, then highlight the red and
green lines for your changes, right click and select 'Stage Selected
Lines'. Alternatively, if an entire file is ready to be committed, just
double click on the file under 'Modified' and it will be marked as
Staged.
Once the descriptions are done and all the edits you would like to
commit have been staged, press 'Commit' on the right of the text
boxes.
If the commit fails due to persisting errors, a text box will appear
showing the errors. You can correct these errors within 'git cola' by
right-clicking on the file in which the error occurred and selecting
'Launch Diff Tool'. Make necessary corrections, close the Diff Tool and
'Stage' the corrected file again. It might be necessary to refresh
'git cola' in order for the file to be shown under 'Modified' again.
Note: Be sure to add any other changes that haven't already been
explained in the extended description.
When ready, select 'Commit' again. Once all errors have been satisfied
and the commit succeeds, move to the command line and run 'git push'.
**Note:** To submit as a draft, use 'git push origin HEAD:refs/drafts/master'
Submitting as a draft means that your commit will be on coreboot.org, but is
only visible to those you add as reviewers.
## Part 5: Getting your commit reviewed
Your commits can now be seen on review.coreboot.org if you select “My”
and click on “Changes” and can be reviewed by others. Your code will
first be reviewed by build bot (Jenkins), which will either give you a warning
or verify a successful build; if so, your commit will receive a +1. Other
users may also give your commit +1. For a commit to be merged, it needs
to receive a +2.**Note:** A +1 and a +1 does not make a +2. Only certain users
can give a +2.
## Part 6 (optional): bash-git-prompt
To help make it easier to understand the state of the git repository
without running 'git status' or 'git log', there is a way to make the
command line show the status of the repository at every point. This
is through bash-git-prompt.
Instructions for installing this are found at:
https://github.com/magicmonty/bash-git-prompt
**Note:** Feel free to search for different versions of git prompt,
as this one is specific to bash.
Alternatively, follow the instructions below:
Run the following two commands in the command line:
cd
git clone https://github.com/magicmonty/bash-git-prompt.git .bash-git-prompt --depth=1
**Note:** cd will change your directory to your home directory, so the
git clone command will be run there.
Finally, open the ~/.bashrc file and append the following two lines:
GIT_PROMPT_ONLY_IN_REPO=1
source ~/.bash-git-prompt/gitprompt.sh
Now, whenever you are in a git repository, it will continuously display
its state.
There also are additional configurations that you can change depending on your
preferences. If you wish to do so, look at the "All configs for .bashrc" section
on https://github.com/magicmonty/bash-git-prompt. Listed in that section are
various lines that you can copy, uncomment and add to your .bashrc file to
change the configurations. Example configurations include avoid fetching remote
status, and supporting versions of Git older than 1.7.10.
## Appendix: Miscellaneous Advice
### Updating a commit after running git push:
Suppose you would like to update a commit that has already been pushed to the
remote repository. If the commit you wish to update is the most recent
commit you have made, after making your desired changes, stage the files
(either using git add or in git cola), and amend the commit. To do so,
if you are using the command line, run "git commit --amend." If you are
using git cola, click on the gear icon located on the upper left side under
**Commit** and select **Amend Last Commit** in the drop down menu. Then, stage
the files you have changed, commit the changes, and run git push to push the
changes to the remote repository. Your change should be reflected in Gerrit as
a new patch set.
If, however, the commit you wish to update is not the most recent commit you
have made, you will first need to checkout that commit. To do so, find the
URL of the commit on <https://review.coreboot.org> and go to that page; if
the commit is one that you previously pushed, it can be found by selecting
**My** and then **Changes** in the upper left corner. To checkout this commit,
in the upper right corner, click on **Download**, and copy the command listed
next to checkout by clicking **Copy to clipboard**. Then, run the copied
command in your coreboot repository. Now, the last commit should be the most
recent commit to that patch; to update it, make your desired changes, stage
the files, then amend and push the commit using the instructions in the above
paragraph.

View File

@@ -7,7 +7,7 @@ PDFLATEX=pdflatex -t a4
FIGS=codeflow.pdf hypertransport.pdf
all: corebootPortingGuide.pdf
all: corebootPortingGuide.pdf Kconfig.pdf
SVG2PDF=$(shell which svg2pdf)
INKSCAPE=$(shell which inkscape)
@@ -39,6 +39,30 @@ corebootPortingGuide.toc: $(FIGS) corebootBuildingGuide.tex
corebootPortingGuide.pdf: $(FIGS) corebootBuildingGuide.tex corebootPortingGuide.toc
$(PDFLATEX) corebootBuildingGuide.tex
Kconfig.pdf: Kconfig.tex mainboardkconfig.tex cpukconfig.tex socketfkconfig.tex
$(PDFLATEX) $<
# quick, somebody! make me a macro!
mainboardkconfig.tex: ../src/mainboard/Kconfig
cat beginverbatim.tex > $@
grep '^config' $< | awk '{print $2}' >>$@
cat endverbatim.tex >> $@
skconfig.tex: ../src/mainboard/amd/serengeti_cheetah/Kconfig
cat beginverbatim.tex > $@
grep '^config' $< | awk '{print $2}' >>$@
cat endverbatim.tex >> $@
cpukconfig.tex: ../src/cpu/Kconfig
cat beginverbatim.tex > $@
grep '^config' $< | awk '{print $2}' >>$@
cat endverbatim.tex >> $@
socketfkconfig.tex: ../src/cpu/amd/socket_F/Kconfig
cat beginverbatim.tex > $@
grep '^config' $< | awk '{print $2}' >>$@
cat endverbatim.tex >> $@
sphinx:
$(MAKE) -f Makefile.sphinx html
@@ -46,10 +70,7 @@ clean-sphinx:
$(MAKE) -f Makefile.sphinx clean
clean: clean-sphinx
rm -f *.aux *.idx *.log *.toc *.out $(FIGS)
rm -f *.aux *.idx *.log *.toc *.out $(FIGS) mainboardkconfig.tex skconfig.tex cpukconfig.tex socketfkconfig.tex
distclean: clean
rm -f corebootPortingGuide.pdf
livesphinx:
$(MAKE) -f Makefile.sphinx livehtml SPHINXOPTS="$(SPHINXOPTS)"
rm -f corebootPortingGuide.pdf Kconfig.pdf

View File

@@ -2,11 +2,10 @@
#
# You can set these variables from the command line.
SPHINXOPTS =
SPHINXBUILD = sphinx-build
SPHINXAUTOBUILD = sphinx-autobuild
PAPER =
BUILDDIR = _build
SPHINXOPTS =
SPHINXBUILD = sphinx-build
PAPER =
BUILDDIR = _build
# Internal variables.
PAPEROPT_a4 = -D latex_paper_size=a4
@@ -47,7 +46,7 @@ help:
.PHONY: clean
clean:
rm -rf $(BUILDDIR)
rm -rf $(BUILDDIR)/*
.PHONY: html
html:
@@ -55,13 +54,6 @@ html:
@echo
@echo "Build finished. The HTML pages are in $(BUILDDIR)/html."
.PHONY: livehtml
livehtml:
@echo "Starting sphinx-autobuild. The HTML pages are in $(BUILDDIR)."
@echo "Press Ctrl-C to stop."
@echo
$(SPHINXAUTOBUILD) -b html $(ALLSPHINXOPTS) $(BUILDDIR)
.PHONY: dirhtml
dirhtml:
$(SPHINXBUILD) -b dirhtml $(ALLSPHINXOPTS) $(BUILDDIR)/dirhtml

View File

@@ -16,12 +16,6 @@ This is an (incomplete) list of POST codes emitted by coreboot v4.
0x66 Devices have been enumerated
0x88 Devices have been configured
0x89 Devices have been enabled
0xe0 Boot media (e.g. SPI ROM) is corrupt
0xe1 Resource stored within CBFS is corrupt
0xe2 Vendor binary (e.g. FSP) generated a fatal error
0xe3 RAM could not be initialized
0xe4 Critical hardware component could not initialize
0xe5 Video subsystem failed to initialize
0xf8 Entry into elf boot
0xf3 Jumping to payload

View File

@@ -0,0 +1,290 @@
New config language for LinuxBIOS
\begin{abstract}
We describe the new configuration language for LinuxBIOS.
\end{abstract}
\section{Scope}
This document defines the new configuration language for LinuxBIOS.
\section{Goals}
The goals of the new language are these:
\begin{itemize}
\item Simplified Makefiles so people can see what is set
\item Move from the regular-expression-based language to something
a bit more comprehensible and flexible
\item make the specification easier for people to use and understand
\item allow unique register-set-specifiers for each chip
\item allow generic register-set-specifiers for each chip
\item generate static initialization code, as needed, for the
specifiers.
\end{itemize}
\section{Language}
Here is the new language. It is very similar to the old one, differing
in only a few respects. It borrows heavily from Greg Watson's suggestions.
I am presenting it in a pseudo-BNF in the hopes it will be easier. Things
in '' are keywords; things in ``'' are strings in the actual text.
\begin{verbatim}
#exprs are composed of factor or factor + factor etc.
expr ::= factor ( ``+'' factor | ``-'' factor | )*
#factors are term or term * term or term / term or ...
factor ::= term ( ``*'' term | ``/'' term | ... )*
#
unary-op ::= ``!'' ID
# term is a number, hexnumber, ID, unary-op, or a full-blown expression
term ::= NUM | XNUM | ID | unary-op | ``(`` expr ``)''
# Option command. Can be an expression or quote-string.
# Options are used in the config tool itself (in expressions and 'if')
# and are also passed to the C compiler when building linuxbios.
# It is an error to have two option commands in a file.
# It is an error to have an option command after the ID has been used
# in an expression (i.e. 'set after used' is an error)
option ::= 'option' ID '=' (``value'' | term)
# Default command. The ID is set to this value if no option command
# is scanned.
# Multiple defaults for an ID will produce warning, but not errors.
# It is OK to scan a default command after use of an ID.
# Options always over-ride defaults.
default ::= 'default' ID '=' (``value'' | term)
# the mainboard, southbridge, northbridge commands
# cause sourcing of Config.lb files as in the old config tool
# as parts are sourced, a device tree is built. The structure
# of the tree is determined by the structure of the components
# as they are specified. To attach a superio to a southbridge, for
# example, one would do this:
# southbridge acer/5432
# superio nsc/123
# end
# end
# the tool generates static initializers for this hierarchy.
# add C code to the current component (motherboard, etc. )
# to initialise the component-INDEPENDENT structure members
init ::= 'init' ``CODE''
# add C code to the current component (motherboard, etc. )
# to initialise the component-DEPENDENT structure members
register ::= 'register' ``CODE''
# mainboard command
# statements in this block will set variables controlling the mainboard,
# and will also place components (northbridge etc.) in the device tree
# under this mainboard
mainboard ::= 'mainboard' PATH (statements)* 'end'
# standard linuxbios commands
southbridge ::= 'southbridge' PATH (statemnts)* 'end'
northbridge ::= 'northbridge' PATH (statemnts)* 'end'
superio ::= 'superio PATH (statemnts)* 'end'
cpu ::= 'cpu' PATH (statemnts)* 'end'
arch ::= 'arch' PATH (statemnts)* 'end'
# files for building linuxbios
# include a file in crt0.S
mainboardinit ::= 'mainboardinit' PATH
# object file
object ::= 'object' PATH
# driver objects are just built into the image in a different way
driver ::= 'driver' PATH
# Use the Config.lb file in the PATH
dir ::= 'dir' PATH
# add a file to the set of ldscript files
ldscript ::= 'ldscript' PATH
# dependencies or actions for the makerule command
dep ::= 'dep' ``dependency-string''
act ::= 'act' ``actions''
depsacts ::= (dep | act)*
# set up a makerule
#
makerule ::= 'makerule' PATH depsacts
#defines for use in makefiles only
# note usable in the config tool, not passed to cc
makedefine ::= 'makedefine' ``RAWTEXT''
# add an action to an existing make rule
addaction ::= 'addaction' PATH ``ACTION''
# statements
statement ::=
option
| default
| cpu
| arch
| northbridge
| southbridge
| superio
| object
| driver
| mainboardinit
| makerule
| makedefine
| addaction
| init
| register
| iif
| dir
| ldscript
statements ::= (statement)*
# target directory specification
target ::= 'target' PATH
# and the whole thing
board ::= target (option)* mainboard
\end{verbatim}
\subsubsection{Command definitions}
\subsubsubsection{option}
\subsubsubsection{default}
\subsubsubsection{cpu}
\subsubsubsection{arch}
\subsubsubsection{northbridge}
\subsubsubsection{southbridge}
\subsubsubsection{superio}
\subsubsubsection{object}
\subsubsubsection{driver}
\subsubsubsection{mainboardinit}
\subsubsubsection{makerule}
\subsubsubsection{makedefine}
\subsubsubsection{addaction}
\subsubsubsection{init}
\subsubsubsection{register}
\subsubsubsection{iif}
\subsubsubsection{dir}
\subsubsubsection{ldscript}
A sample file:
\begin{verbatim}
target x
# over-ride the default ROM size in the mainboard file
option CONFIG_ROM_SIZE=1024*1024
mainboard amd/solo
end
\end{verbatim}
Sample mainboard file
\begin{verbatim}
#
###
### Set all of the defaults for an x86 architecture
###
arch i386 end
cpu k8 end
#
option CONFIG_DEBUG=1
default CONFIG_USE_FALLBACK_IMAGE=1
option A=(1+2)
option B=0xa
#
###
### Build our 16 bit and 32 bit linuxBIOS entry code
###
mainboardinit cpu/i386/entry16.inc
mainboardinit cpu/i386/entry32.inc
ldscript cpu/i386/entry16.lds
ldscript cpu/i386/entry32.lds
#
###
### Build our reset vector (This is where linuxBIOS is entered)
###
if CONFIG_USE_FALLBACK_IMAGE
mainboardinit cpu/i386/reset16.inc
ldscript cpu/i386/reset16.lds
else
mainboardinit cpu/i386/reset32.inc
ldscript cpu/i386/reset32.lds
end
.
.
.
if CONFIG_USE_FALLBACK_IMAGE mainboardinit arch/i386/lib/noop_failover.inc end
#
###
### Romcc output
###
#makerule ./failover.E dep "$(CONFIG_MAINBOARD)/failover.c" act "$(CPP) -I$(TOP)/src $(CPPFLAGS) $(CONFIG_MAINBOARD)/failover.c > ./failever.E"
#makerule ./failover.inc dep "./romcc ./failover.E" act "./romcc -O ./failover.E > failover.inc"
#mainboardinit ./failover.inc
makerule ./auto.E dep "$(CONFIG_MAINBOARD)/auto.c" act "$(CPP) -I$(TOP)/src -$(ROMCCPPFLAGS) $(CPPFLAGS) $(CONFIG_MAINBOARD)/auto.c > ./auto.E"
makerule ./auto.inc dep "./romcc ./auto.E" act "./romcc -O ./auto.E > auto.inc"
mainboardinit ./auto.inc
#
###
### Include the secondary Configuration files
###
northbridge amd/amdk8
end
southbridge amd/amd8111
end
#mainboardinit arch/i386/smp/secondary.inc
superio nsc/pc87360
register "com1={1} com2={0} floppy=1 lpt=1 keyboard=1"
end
dir /pc80
##dir /src/superio/winbond/w83627hf
cpu p5 end
cpu p6 end
cpu k7 end
cpu k8 end
#
###
### Build the objects we have code for in this directory.
###
##object mainboard.o
driver mainboard.o
object static_devices.o
if CONFIG_HAVE_MP_TABLE object mptable.o end
if CONFIG_HAVE_PIRQ_TABLE object irq_tables.o end
### Location of the DIMM EEPROMS on the SMBUS
### This is fixed into a narrow range by the DIMM package standard.
###
option SMBUS_MEM_DEVICE_START=(0xa << 3)
option SMBUS_MEM_DEVICE_END=(SMBUS_MEM_DEVICE_START +1)
option SMBUS_MEM_DEVICE_INC=1
#
### The linuxBIOS bootloader.
###
option CONFIG_PAYLOAD_SIZE = (CONFIG_ROM_SECTION_SIZE - CONFIG_ROM_IMAGE_SIZE)
option CONFIG_ROM_PAYLOAD_START = (0xffffffff - CONFIG_ROM_SIZE + CONFIG_ROM_SECTION_OFFSET + 1)
#
\end{verbatim}
I've found the output of the new tool to be easier to
handle. Makefile.settings looks like this, for example:
\begin{verbatim}
TOP:=/home/rminnich/src/yapps2/freebios2
TARGET_DIR:=x
export CONFIG_MAINBOARD:=/home/rminnich/src/yapps2/freebios2/src/mainboard/amd/solo
export CONFIG_ARCH:=i386
export CONFIG_RAMBASE:=0x4000
export CONFIG_ROM_IMAGE_SIZE:=65535
export CONFIG_PAYLOAD_SIZE:=131073
export CONFIG_MAX_CPUS:=1
export CONFIG_HEAP_SIZE:=8192
export CONFIG_STACK_SIZE:=8192
export CONFIG_MEMORY_HOLE:=0
export COREBOOT_VERSION:=1.1.0
export CC:=$(CONFIG_CROSS_COMPILE)gcc
\end{verbatim}
In other words, instead of expressions, we see the values. It's easier to
deal with.

View File

@@ -8,9 +8,8 @@ listed as consumable is subject to change without notice.
## Background and Usage
coreboot passes information to downstream users using coreboot tables. These
table definitions can be found in
`./src/commonlib/include/commonlib/coreboot_tables.h` and
`./payloads/libpayload/include/coreboot_tables.h` respectively within coreboot
table definitions can be found in src/include/boot/coreboot_tables.h and
payloads/libpayload/include/coreboot_tables.h respectively within coreboot
and libpayload. One of the most vital and important pieces of information
found within these tables is the memory map of the system indicating
available and reserved memory.

View File

@@ -1,234 +0,0 @@
# Adding new devices to a device tree
## Introduction
ACPI exposes a platform-independent interface for operating systems to perform
power management and other platform-level functions. Some operating systems
also use ACPI to enumerate devices that are not immediately discoverable, such
as those behind I2C or SPI busses (in contrast to PCI). This document discusses
the way that coreboot uses the concept of a "device tree" to generate ACPI
tables for usage by the operating system.
## Devicetree and overridetree (if applicable)
For mainboards that are organized around a "reference board" or "baseboard"
model (see ``src/mainboard/google/octopus`` or ``hatch`` for examples), there is
typically a devicetree.cb file that all boards share, and any differences for a
specific board ("variant") are captured in the overridetree.cb file. Any
settings changed in the overridetree take precedence over those in the main
devicetree. Note, not all mainboards will have the devicetree/overridetree
distinction, and may only have a devicetree.cb file. Or you can always just
write the ASL (ACPI Source Language) code yourself.
## Device drivers
Let's take a look at an example entry from
``src/mainboard/google/hatch/variant/hatch/overridetree.cb``:
```
device pci 15.0 on
chip drivers/i2c/generic
register "hid" = ""ELAN0000""
register "desc" = ""ELAN Touchpad""
register "irq" = "ACPI_IRQ_WAKE_EDGE_LOW(GPP_A21_IRQ)"
register "wake" = "GPE0_DW0_21"
device i2c 15 on end
end
end # I2C #0
```
When this entry is processed during ramstage, it will create a device in the
ACPI SSDT table (all devices in devicetrees end up in the SSDT table). The ACPI
generation routines in coreboot actually generate the raw bytecode that
represents the device's structure, but looking at ASL code is easier to
understand; see below for what the disassembled bytecode looks like:
```
Scope (\_SB.PCI0.I2C0)
{
Device (D015)
{
Name (_HID, "ELAN0000") // _HID: Hardware ID
Name (_UID, Zero) // _UID: Unique ID
Name (_DDN, "ELAN Touchpad") // _DDN: DOS Device Name
Method (_STA, 0, NotSerialized) // _STA: Status
{
Return (0x0F)
}
Name (_CRS, ResourceTemplate () // _CRS: Current Resource Settings
{
I2cSerialBusV2 (0x0015, ControllerInitiated, 400000,
AddressingMode7Bit, "\\_SB.PCI0.I2C0",
0x00, ResourceConsumer, , Exclusive, )
Interrupt (ResourceConsumer, Edge, ActiveLow, ExclusiveAndWake, ,, )
{
0x0000002D,
}
})
Name (_S0W, 0x04) // _S0W: S0 Device Wake State
Name (_PRW, Package (0x02) // _PRW: Power Resources for Wake
{
0x15, // GPE #21
0x03 // Sleep state S3
})
}
}
```
You can see it generates _HID, _UID, _DDN, _STA, _CRS, _S0W, and _PRW
names/methods in the Device's scope.
## Utilizing a device driver
The device driver must be enabled for your build. There will be a CONFIG option
in the Kconfig file in the directory that the driver is in (e.g.,
``src/drivers/i2c/generic`` contains a Kconfig file; the option here is named
CONFIG_DRIVERS_I2C_GENERIC). The config option will need to be added to your
mainboard's Kconfig file (e.g., ``src/mainboard/google/hatch/Kconfig``) in order
to be compiled into your build.
## Diving into the above example:
Let's take a look at how the devicetree language corresponds to the generated
ASL.
First, note this:
```
chip drivers/i2c/generic
```
This means that the device driver we're using has a corresponding structure,
located at ``src/drivers/i2c/generic/chip.h``, named **struct
drivers_i2c_generic_config** and it contains many properties you can specify to
be included in the ACPI table.
### hid
```
register "hid" = ""ELAN0000""
```
This corresponds to **const char *hid** in the struct. In the ACPI ASL, it
translates to:
```
Name (_HID, "ELAN0000") // _HID: Hardware ID
```
under the device. **This property is used to match the device to its driver
during enumeration in the OS.**
### desc
```
register "desc" = ""ELAN Touchpad""
```
corresponds to **const char *desc** and in ASL:
```
Name (_DDN, "ELAN Touchpad") // _DDN: DOS Device Name
```
### irq
It also adds the interrupt,
```
Interrupt (ResourceConsumer, Edge, ActiveLow, ExclusiveAndWake, ,, )
{
0x0000002D,
}
```
which comes from:
```
register "irq" = "ACPI_IRQ_WAKE_EDGE_LOW(GPP_A21_IRQ)"
```
The GPIO pin IRQ settings control the "Edge", "ActiveLow", and
"ExclusiveAndWake" settings seen above (edge means it is an edge-triggered
interrupt as opposed to level-triggered; active low means the interrupt is
triggered on a falling edge).
Note that the ACPI_IRQ_WAKE_EDGE_LOW macro informs the platform that the GPIO
will be routed through SCI (ACPI's System Control Interrupt) for use as a wake
source. Also note that the IRQ names are SoC-specific, and you will need to
find the names in your SoC's header file. The ACPI_* macros are defined in
``src/arch/x86/include/arch/acpi_device.h``.
Using a GPIO as an IRQ requires that it is configured in coreboot correctly.
This is often done in a mainboard-specific file named ``gpio.c``.
### wake
The last register is:
```
register "wake" = "GPE0_DW0_21"
```
which indicates that the method of waking the system using the touchpad will be
through a GPE, #21 associated with DW0, which is set up in devicetree.cb from
this example. The "21" indicates GPP_X21, where GPP_X is mapped onto DW0
elsewhere in the devicetree.
The last bit of the definition of that device includes:
```
device i2c 15 on end
```
which means it's an I2C device, with 7-bit address 0x15, and the device is "on",
meaning it will be exposed in the ACPI table. The PCI device that the
controller is located in determines which I2C bus the device is expected to be
found on. In this example, this is I2C bus 0. This also determines the ACPI
"Scope" that the device names and methods will live under, in this case
"\_SB.PCI0.I2C0".
## Other auto-generated names
(see [ACPI specification
6.3](https://uefi.org/sites/default/files/resources/ACPI_6_3_final_Jan30.pdf)
for more details on ACPI methods)
### _S0W (S0 Device Wake State)
_S0W indicates the deepest S0 sleep state this device can wake itself from,
which in this case is 4, representing _D3cold_.
### _PRW (Power Resources for Wake)
_PRW indicates the power resources and events required for wake. There are no
dependent power resources, but the GPE (GPE0_DW0_21) is mentioned here (0x15),
as well as the deepest sleep state supporting waking the system (3), which is
S3.
### _STA (Status)
The _STA method is generated automatically, and its values, 0xF, indicates the
following:
Bit [0] Set if the device is present.
Bit [1] Set if the device is enabled and decoding its resources.
Bit [2] Set if the device should be shown in the UI.
Bit [3] Set if the device is functioning properly (cleared if device failed its diagnostics).
### _CRS (Current resource settings)
The _CRS method is generated automatically, as the driver knows it is an I2C
controller, and so specifies how to configure the controller for proper
operation with the touchpad.
```
Name (_CRS, ResourceTemplate () // _CRS: Current Resource Settings
{
I2cSerialBusV2 (0x0015, ControllerInitiated, 400000,
AddressingMode7Bit, "\\_SB.PCI0.I2C0",
0x00, ResourceConsumer, , Exclusive, )
```
## Notes
- **All fields that are left unspecified in the devicetree are initialized to
zero.**
- **All devices in devicetrees end up in the SSDT table, and are generated in
coreboot's ramstage**

View File

@@ -1,11 +0,0 @@
# Architecture-specific documentation
This section contains documentation about coreboot on specific CPU
architectures.
## RISC-V
- [RISC-V documentation](riscv/index.md)
## x86
- [x86 documentation](x86/index.md)

View File

@@ -1,64 +0,0 @@
# RISC-V architecture documentation
This section contains documentation about coreboot on RISC-V architecture.
## Mode usage
All stages run in M mode.
Payloads have a choice of managing M mode activity: they can control
everything or nothing.
Payloads run from the romstage (i.e. rampayloads) are started in M mode.
The payload must, for example, prepare and install its own SBI.
Payloads run from the ramstage are started in S mode, and trap delegation
will have been done. These payloads rely on the SBI and can not replace it.
## Stage handoff protocol
On entry to a stage or payload (including SELF payloads),
* all harts are running.
* A0 is the hart ID.
* A1 is the pointer to the Flattened Device Tree (FDT).
* A2 contains the additional program calling argument:
- cbmem_top for ramstage
- the address of the payload for opensbi
## Additional payload handoff requirements
The location of cbmem should be placed in a node in the FDT.
## OpenSBI
In case the payload doesn't install it's own SBI, like the [RISCV-PK] does,
[OpenSBI] can be used instead.
It's loaded into RAM after coreboot has finished loading the payload.
coreboot then will jump to OpenSBI providing a pointer to the real payload,
which OpenSBI will jump to once the SBI is installed.
Besides providing SBI it also sets protected memory regions and provides
a platform independent console.
The OpenSBI code is always run in M mode.
## Trap delegation
Traps are delegated to the payload.
## SMP within a stage
At the beginning of each stage, all harts save 0 are spinning in a loop on
a semaphore. At the end of the stage harts 1..max are released by changing
the semaphore.
A possible way to do this is to have a pointer to a struct containing
variables, e.g.
```c
struct blocker {
void (*fn)(); // never returns
}
```
The hart blocks until fn is non-null, and then calls it. If fn returns, we
will panic if possible, but behavior is largely undefined.
Only hart 0 runs through most of the code in each stage.
[RISCV-PK]: https://github.com/riscv/riscv-pk
[OpenSBI]: https://github.com/riscv/opensbi

View File

@@ -1,56 +0,0 @@
# x86 architecture documentation
This section contains documentation about coreboot on x86 architecture.
* [x86 PAE support](pae.md)
## State of x86_64 support
At the moment there's no single board that supports x86_64 or to be exact
`ARCH_RAMSTAGE_X86_64` and `ARCH_ROMSTAGE_X86_64`.
In order to add support for x86_64 the following assumptions are made:
* The CPU supports long mode
* All memory returned by malloc must be below 4GiB in physical memory
* All code that is to be run must be below 4GiB in physical memory
* The high dword of pointers is always zero
* The reference implementation is qemu
* The CPU supports 1GiB hugepages
## Assuptions for all stages using the reference implementation
* 0-4GiB are identity mapped using 2MiB-pages as WB
* Memory above 4GiB isn't accessible
* page tables reside in memory mapped ROM
* A stage can install new page tables in RAM
## Page tables
Page tables are generated by a tool in `util/pgtblgen/pgtblgen`. It writes
the page tables to a file which is then included into the CBFS as file called
`pagetables`.
To generate the static page tables it must know the physical address where to
place the file.
The page tables contains the following structure:
* PML4E pointing to PDPE
* PDPE with *$n* entries each pointing to PDE
* *$n* PDEs with 512 entries each
At the moment *$n* is 4, which results in identity mapping the lower 4 GiB.
## Steps to add basic support for x86_64
* Add x86_64 toolchain support - *DONE*
* Fix compilation errors - *DONE*
* Fix linker errors - *TODO*
* Add x86_64 rmodule support - *DONE*
* Add x86_64 exception handlers - *TODO*
* Setup page tables for long mode - *DONE*
* Add assembly code for long mode - *DONE*
* Add assembly code for postcar stage - *TODO*
* Add assembly code to return to protected mode - *TODO*
* Implement reference code for mainboard `emulation/qemu-q35` - *TODO*
## Porting other boards
* Fix compilation errors
* Test how well CAR works with x86_64 and paging
* Improve mode switches
* Test libgfxinit / VGA Option ROMs / FSP

View File

@@ -1,15 +0,0 @@
# x86_32 PAE documentation
Due to missing x86_64 support it's required to use PAE enabled x86_32 code.
The corresponding functions can be found in ``src/cpu/x86/pae/``.
## Memory clearing helper functions
To clear all DRAM on request of the
[Security API](../../security/memory_clearing.md), a helper function can be used
called `memset_pae`.
The function has additional requirements in contrast to `memset`, and has more
overhead as it uses virtual memory to access memory above 4GiB.
Memory is cleared in 2MiB chunks, which might take a while.
Make sure to enable caches through MTRRs, otherwise `memset_pae` will be slow!

View File

@@ -174,7 +174,7 @@ with
regards to the erase block sizes on the ROM - allowing one to replace a
component at runtime without disturbing the others.
'offset' is the offset of the first CBFS component (from the start of
'offset' is the offset of the the first CBFS component (from the start of
the ROM). This is to allow for arbitrary space to be left at the beginning
of the ROM for things like embedded controller firmware.
@@ -384,7 +384,7 @@ PAYLOAD_SEGMENT_BSS 0x20535342 The memory specified by the segment
PAYLOAD_SEGMENT_PARAMS 0x41524150 The segment contains information for
the payload
PAYLOAD_SEGMENT_ENTRY 0x52544E45 The segment contains the entry point
for the payload
for the payload
'compression' is the compression scheme for the segment. Each segment can
be independently compressed. There are three compression types defined by

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@@ -98,10 +98,10 @@
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@@ -1,938 +0,0 @@
# Coding Style
This is a short document describing the preferred coding style for the
coreboot project. It is in many ways exactly the same as the Linux
kernel coding style. In fact, most of this document has been copied from
the [Linux kernel coding style](http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/plain/Documentation/CodingStyle?id=HEAD)
Please at least consider the points made here.
First off, I'd suggest printing out a copy of the GNU coding standards,
and NOT read it. Burn them, it's a great symbolic gesture.
Anyway, here goes:
## Indentation
Tabs are 8 characters, and thus indentations are also 8 characters.
There are heretic movements that try to make indentations 4 (or even 2!)
characters deep, and that is akin to trying to define the value of PI to
be 3.
Rationale: The whole idea behind indentation is to clearly define where
a block of control starts and ends. Especially when you've been looking
at your screen for 20 straight hours, you'll find it a lot easier to
see how the indentation works if you have large indentations.
Now, some people will claim that having 8-character indentations makes
the code move too far to the right, and makes it hard to read on a
80-character terminal screen. The answer to that is that if you need
more than 3 levels of indentation, you're screwed anyway, and should
fix your program.
In short, 8-char indents make things easier to read, and have the added
benefit of warning you when you're nesting your functions too deep.
Heed that warning.
The preferred way to ease multiple indentation levels in a switch
statement is to align the "switch" and its subordinate "case" labels
in the same column instead of "double-indenting" the "case" labels.
E.g.:
```c
switch (suffix) {
case 'G':
case 'g':
mem <<= 30;
break;
case 'M':
case 'm':
mem <<= 20;
break;
case 'K':
case 'k':
mem <<= 10;
/* fall through */
default:
break;
}
```
Don't put multiple statements on a single line unless you have
something to hide:
```c
if (condition) do_this;
do_something_everytime;
```
Don't put multiple assignments on a single line either. Kernel coding
style is super simple. Avoid tricky expressions.
Outside of comments, documentation and except in Kconfig, spaces are
never used for indentation, and the above example is deliberately
broken.
Get a decent editor and don't leave whitespace at the end of lines.
## Breaking long lines and strings
Coding style is all about readability and maintainability using commonly
available tools.
The limit on the length of lines is 96 columns and this is a strongly
preferred limit.
Statements longer than 96 columns will be broken into sensible chunks,
unless exceeding 96 columns significantly increases readability and does
not hide information. Descendants are always substantially shorter than
the parent and are placed substantially to the right. The same applies
to function headers with a long argument list. However, never break
user-visible strings such as printk messages, because that breaks the
ability to grep for them.
## Placing Braces and Spaces
The other issue that always comes up in C styling is the placement of
braces. Unlike the indent size, there are few technical reasons to
choose one placement strategy over the other, but the preferred way, as
shown to us by the prophets Kernighan and Ritchie, is to put the opening
brace last on the line, and put the closing brace first, thusly:
```c
if (x is true) {
we do y
}
```
This applies to all non-function statement blocks (if, switch, for,
while, do). E.g.:
```c
switch (action) {
case KOBJ_ADD:
return "add";
case KOBJ_REMOVE:
return "remove";
case KOBJ_CHANGE:
return "change";
default:
return NULL;
}
```
However, there is one special case, namely functions: they have the
opening brace at the beginning of the next line, thus:
```c
int function(int x)
{
body of function
}
```
Heretic people all over the world have claimed that this inconsistency
is ... well ... inconsistent, but all right-thinking people know that
(a) K&R are _right_ and (b) K&R are right. Besides, functions are
special anyway (you can't nest them in C).
Note that the closing brace is empty on a line of its own, _except_ in
the cases where it is followed by a continuation of the same statement,
ie a "while" in a do-statement or an "else" in an if-statement, like
this:
```c
do {
body of do-loop
} while (condition);
```
and
```c
if (x == y) {
..
} else if (x > y) {
...
} else {
....
}
```
Rationale: K&R.
Also, note that this brace-placement also minimizes the number of empty
(or almost empty) lines, without any loss of readability. Thus, as the
supply of new-lines on your screen is not a renewable resource (think
25-line terminal screens here), you have more empty lines to put
comments on.
Do not unnecessarily use braces where a single statement will do.
```c
if (condition)
action();
```
and
```c
if (condition)
do_this();
else
do_that();
```
This does not apply if only one branch of a conditional statement is a
single statement; in the latter case use braces in both branches:
```c
if (condition) {
do_this();
do_that();
} else {
otherwise();
}
```
### Spaces
Linux kernel style for use of spaces depends (mostly) on
function-versus-keyword usage. Use a space after (most) keywords. The
notable exceptions are sizeof, typeof, alignof, and __attribute__,
which look somewhat like functions (and are usually used with
parentheses in Linux, although they are not required in the language, as
in: "sizeof info" after "struct fileinfo info;" is declared).
So use a space after these keywords:
```
if, switch, case, for, do, while
```
but not with sizeof, typeof, alignof, or __attribute__. E.g.,
```c
s = sizeof(struct file);
```
Do not add spaces around (inside) parenthesized expressions. This
example is
- bad*:
```c
s = sizeof( struct file );
```
When declaring pointer data or a function that returns a pointer type,
the preferred use of '*' is adjacent to the data name or function
name and not adjacent to the type name. Examples:
```c
char *linux_banner;
unsigned long long memparse(char *ptr, char **retptr);
char *match_strdup(substring_t *s);
```
Use one space around (on each side of) most binary and ternary
operators, such as any of these:
```
=  +  -  <  >  *  /  %  |  &  ^  <=  >=  ==  !=  ?  :
```
but no space after unary operators:
```
&  *  +  -  ~  !  sizeof  typeof  alignof  __attribute__  defined
```
no space before the postfix increment & decrement unary operators:
```
++  --
```
no space after the prefix increment & decrement unary operators:
```
++  --
```
and no space around the '.' and "->" structure member operators.
Do not leave trailing whitespace at the ends of lines. Some editors with
"smart" indentation will insert whitespace at the beginning of new
lines as appropriate, so you can start typing the next line of code
right away. However, some such editors do not remove the whitespace if
you end up not putting a line of code there, such as if you leave a
blank line. As a result, you end up with lines containing trailing
whitespace.
Git will warn you about patches that introduce trailing whitespace, and
can optionally strip the trailing whitespace for you; however, if
applying a series of patches, this may make later patches in the series
fail by changing their context lines.
### Naming
C is a Spartan language, and so should your naming be. Unlike Modula-2
and Pascal programmers, C programmers do not use cute names like
ThisVariableIsATemporaryCounter. A C programmer would call that variable
"tmp", which is much easier to write, and not the least more difficult
to understand.
HOWEVER, while mixed-case names are frowned upon, descriptive names for
global variables are a must. To call a global function "foo" is a
shooting offense.
GLOBAL variables (to be used only if you _really_ need them) need to
have descriptive names, as do global functions. If you have a function
that counts the number of active users, you should call that
"count_active_users()" or similar, you should _not_ call it
"cntusr()".
Encoding the type of a function into the name (so-called Hungarian
notation) is brain damaged - the compiler knows the types anyway and can
check those, and it only confuses the programmer. No wonder MicroSoft
makes buggy programs.
LOCAL variable names should be short, and to the point. If you have some
random integer loop counter, it should probably be called "i". Calling
it "loop_counter" is non-productive, if there is no chance of it
being mis-understood. Similarly, "tmp" can be just about any type of
variable that is used to hold a temporary value.
If you are afraid to mix up your local variable names, you have another
problem, which is called the function-growth-hormone-imbalance syndrome.
See chapter 6 (Functions).
## Typedefs
Please don't use things like "vps_t".
It's a _mistake_ to use typedef for structures and pointers. When you
see a
```c
vps_t a;
```
in the source, what does it mean?
In contrast, if it says
```c
struct virtual_container *a;
```
you can actually tell what "a" is.
Lots of people think that typedefs "help readability". Not so. They
are useful only for:
(a) totally opaque objects (where the typedef is actively used to
_hide_ what the object is).
Example: "pte_t" etc. opaque objects that you can only access using
the proper accessor functions.
NOTE! Opaqueness and "accessor functions" are not good in themselves.
The reason we have them for things like pte_t etc. is that there really
is absolutely _zero_ portably accessible information there.
(b) Clear integer types, where the abstraction _helps_ avoid confusion
whether it is "int" or "long".
u8/u16/u32 are perfectly fine typedefs, although they fit into category
(d) better than here.
NOTE! Again - there needs to be a _reason_ for this. If something is
"unsigned long", then there's no reason to do
```c
typedef unsigned long myflags_t;
```
but if there is a clear reason for why it under certain circumstances
might be an "unsigned int" and under other configurations might be
"unsigned long", then by all means go ahead and use a typedef.
(c) when you use sparse to literally create a _new_ type for
type-checking.
(d) New types which are identical to standard C99 types, in certain
exceptional circumstances.
Although it would only take a short amount of time for the eyes and
brain to become accustomed to the standard types like 'uint32_t',
some people object to their use anyway.
Therefore, the Linux-specific 'u8/u16/u32/u64' types and their signed
equivalents which are identical to standard types are permitted --
although they are not mandatory in new code of your own.
When editing existing code which already uses one or the other set of
types, you should conform to the existing choices in that code.
(e) Types safe for use in userspace.
In certain structures which are visible to userspace, we cannot require
C99 types and cannot use the 'u32' form above. Thus, we use __u32
and similar types in all structures which are shared with userspace.
Maybe there are other cases too, but the rule should basically be to
NEVER EVER use a typedef unless you can clearly match one of those
rules.
In general, a pointer, or a struct that has elements that can reasonably
be directly accessed should _never_ be a typedef.
## Functions
Functions should be short and sweet, and do just one thing. They should
fit on one or two screenfuls of text (the ISO/ANSI screen size is 80x24,
as we all know), and do one thing and do that well.
The maximum length of a function is inversely proportional to the
complexity and indentation level of that function. So, if you have a
conceptually simple function that is just one long (but simple)
case-statement, where you have to do lots of small things for a lot of
different cases, it's OK to have a longer function.
However, if you have a complex function, and you suspect that a
less-than-gifted first-year high-school student might not even
understand what the function is all about, you should adhere to the
maximum limits all the more closely. Use helper functions with
descriptive names (you can ask the compiler to in-line them if you think
it's performance-critical, and it will probably do a better job of it
than you would have done).
Another measure of the function is the number of local variables. They
shouldn't exceed 5-10, or you're doing something wrong. Re-think the
function, and split it into smaller pieces. A human brain can generally
easily keep track of about 7 different things, anything more and it gets
confused. You know you're brilliant, but maybe you'd like to
understand what you did 2 weeks from now.
In source files, separate functions with one blank line. If the function
is exported, the EXPORT* macro for it should follow immediately after
the closing function brace line. E.g.:
```c
int system_is_up(void)
{
return system_state == SYSTEM_RUNNING;
}
EXPORT_SYMBOL(system_is_up);
```
In function prototypes, include parameter names with their data types.
Although this is not required by the C language, it is preferred in
Linux because it is a simple way to add valuable information for the
reader.
## Centralized exiting of functions
Albeit deprecated by some people, the equivalent of the goto statement
is used frequently by compilers in form of the unconditional jump
instruction.
The goto statement comes in handy when a function exits from multiple
locations and some common work such as cleanup has to be done. If there
is no cleanup needed then just return directly.
The rationale is:
- unconditional statements are easier to understand and follow
- nesting is reduced
- errors by not updating individual exit points when making
modifications are prevented
- saves the compiler work to optimize redundant code away ;)
```c
int fun(int a)
{
int result = 0;
char *buffer = kmalloc(SIZE);
if (buffer == NULL)
return -ENOMEM;
if (condition1) {
while (loop1) {
...
}
result = 1;
goto out;
}
...
out:
kfree(buffer);
return result;
}
```
## Commenting
Comments are good, but there is also a danger of over-commenting. NEVER
try to explain HOW your code works in a comment: it's much better to
write the code so that the _working_ is obvious, and it's a waste of
time to explain badly written code.
Generally, you want your comments to tell WHAT your code does, not HOW.
Also, try to avoid putting comments inside a function body: if the
function is so complex that you need to separately comment parts of it,
you should probably go back to chapter 6 for a while. You can make small
comments to note or warn about something particularly clever (or ugly),
but try to avoid excess. Instead, put the comments at the head of the
function, telling people what it does, and possibly WHY it does it.
When commenting the kernel API functions, please use the kernel-doc
format. See the files Documentation/kernel-doc-nano-HOWTO.txt and
scripts/kernel-doc for details.
coreboot style for comments is the C89 "/* ... */" style. You may
use C99-style "// ..." comments.
The preferred style for *short* (multi-line) comments is:
```c
/* This is the preferred style for short multi-line
   comments in the Linux kernel source code.
   Please use it consistently. */
```
The preferred style for *long* (multi-line) comments is:
```c
/*
 * This is the preferred style for multi-line
 * comments in the Linux kernel source code.
 * Please use it consistently.
 *
 * Description:  A column of asterisks on the left side,
 * with beginning and ending almost-blank lines.
 */
```
It's also important to comment data, whether they are basic types or
derived types. To this end, use just one data declaration per line (no
commas for multiple data declarations). This leaves you room for a small
comment on each item, explaining its use.
## You've made a mess of it
That's OK, we all do. You've probably been told by your long-time Unix user
helper that "GNU emacs" automatically formats the C sources for you, and
you've noticed that yes, it does do that, but the defaults it uses are less
than desirable (in fact, they are worse than random typing - an infinite
number of monkeys typing into GNU emacs would never make a good program).
So, you can either get rid of GNU emacs, or change it to use saner values.
To do the latter, you can stick the following in your .emacs file:
```lisp
(defun c-lineup-arglist-tabs-only (ignored)
"Line up argument lists by tabs, not spaces"
(let* ((anchor (c-langelem-pos c-syntactic-element))
(column (c-langelem-2nd-pos c-syntactic-element))
(offset (- (1+ column) anchor))
(steps (floor offset c-basic-offset)))
(* (max steps 1)
c-basic-offset)))
(add-hook 'c-mode-common-hook
(lambda ()
;; Add kernel style
(c-add-style
"linux-tabs-only"
'("linux" (c-offsets-alist
(arglist-cont-nonempty
c-lineup-gcc-asm-reg
c-lineup-arglist-tabs-only))))))
(add-hook 'c-mode-hook
(lambda ()
(let ((filename (buffer-file-name)))
;; Enable kernel mode for the appropriate files
(when (and filename
(string-match (expand-file-name "~/src/linux-trees")
filename))
(setq indent-tabs-mode t)
(c-set-style "linux-tabs-only")))))
```
This will make emacs go better with the kernel coding style for C files
below ~/src/linux-trees.
But even if you fail in getting emacs to do sane formatting, not
everything is lost: use "indent".
Now, again, GNU indent has the same brain-dead settings that GNU emacs
has, which is why you need to give it a few command line options.
However, that's not too bad, because even the makers of GNU indent
recognize the authority of K&R (the GNU people aren't evil, they are
just severely misguided in this matter), so you just give indent the
options "-kr -i8" (stands for "K&R, 8 character indents"), or use
"scripts/Lindent", which indents in the latest style.
"indent" has a lot of options, and especially when it comes to comment
re-formatting you may want to take a look at the man page. But remember:
"indent" is not a fix for bad programming.
## Kconfig configuration files
For all of the Kconfig* configuration files throughout the source tree,
the indentation is somewhat different. Lines under a "config"
definition are indented with one tab, while help text is indented an
additional two spaces. Example:
```kconfig
config AUDIT
bool "Auditing support"
depends on NET
help
  Enable auditing infrastructure that can be used with another
  kernel subsystem, such as SELinux (which requires this for
  logging of avc messages output).  Does not do system-call
  auditing without CONFIG_AUDITSYSCALL.
```
Seriously dangerous features (such as write support for certain
filesystems) should advertise this prominently in their prompt string:
```kconfig
config ADFS_FS_RW
bool "ADFS write support (DANGEROUS)"
depends on ADFS_FS
...
```
For full documentation on the configuration files, see the file
Documentation/kbuild/kconfig-language.txt.
Data structures
---------------
Data structures that have visibility outside the single-threaded
environment they are created and destroyed in should always have
reference counts. In the kernel, garbage collection doesn't exist (and
outside the kernel garbage collection is slow and inefficient), which
means that you absolutely _have_ to reference count all your uses.
Reference counting means that you can avoid locking, and allows multiple
users to have access to the data structure in parallel - and not having
to worry about the structure suddenly going away from under them just
because they slept or did something else for a while.
Note that locking is _not_ a replacement for reference counting.
Locking is used to keep data structures coherent, while reference
counting is a memory management technique. Usually both are needed, and
they are not to be confused with each other.
Many data structures can indeed have two levels of reference counting,
when there are users of different "classes". The subclass count counts
the number of subclass users, and decrements the global count just once
when the subclass count goes to zero.
Examples of this kind of "multi-level-reference-counting" can be found
in memory management ("struct mm_struct": mm_users and mm_count),
and in filesystem code ("struct super_block": s_count and
s_active).
Remember: if another thread can find your data structure, and you don't
have a reference count on it, you almost certainly have a bug.
Macros, Enums and RTL
---------------------
Names of macros defining constants and labels in enums are capitalized.
```c
#define CONSTANT 0x12345
```
Enums are preferred when defining several related constants.
CAPITALIZED macro names are appreciated but macros resembling functions
may be named in lower case.
Generally, inline functions are preferable to macros resembling
functions.
Macros with multiple statements should be enclosed in a do - while
block:
```c
#define macrofun(a, b, c) \
do { \
if (a == 5) \
do_this(b, c); \
} while (0)
```
Things to avoid when using macros:
1) macros that affect control flow:
```c
#define FOO(x) \
do { \
if (blah(x) < 0) \
return -EBUGGERED; \
} while(0)
```
is a *very* bad idea. It looks like a function call but exits the
"calling" function; don't break the internal parsers of those who
will read the code.
2) macros that depend on having a local variable with a magic name:
```c
#define FOO(val) bar(index, val)
```
might look like a good thing, but it's confusing as hell when one reads
the code and it's prone to breakage from seemingly innocent changes.
3) macros with arguments that are used as l-values: FOO(x) = y; will
bite you if somebody e.g. turns FOO into an inline function.
4) forgetting about precedence: macros defining constants using
expressions must enclose the expression in parentheses. Beware of
similar issues with macros using parameters.
```c
#define CONSTANT 0x4000
#define CONSTEXP (CONSTANT | 3)
```
The cpp manual deals with macros exhaustively. The gcc internals manual
also covers RTL which is used frequently with assembly language in the
kernel.
Printing kernel messages
------------------------
Kernel developers like to be seen as literate. Do mind the spelling of
kernel messages to make a good impression. Do not use crippled words
like "dont"; use "do not" or "don't" instead. Make the messages
concise, clear, and unambiguous.
Kernel messages do not have to be terminated with a period.
Printing numbers in parentheses (%d) adds no value and should be
avoided.
There are a number of driver model diagnostic macros in
<linux/device.h> which you should use to make sure messages are
matched to the right device and driver, and are tagged with the right
level: dev_err(), dev_warn(), dev_info(), and so forth. For messages
that aren't associated with a particular device, <linux/printk.h>
defines pr_debug() and pr_info().
Coming up with good debugging messages can be quite a challenge; and
once you have them, they can be a huge help for remote troubleshooting.
Such messages should be compiled out when the DEBUG symbol is not
defined (that is, by default they are not included). When you use
dev_dbg() or pr_debug(), that's automatic. Many subsystems have
Kconfig options to turn on -DDEBUG. A related convention uses
VERBOSE_DEBUG to add dev_vdbg() messages to the ones already enabled
by DEBUG.
Allocating memory
-----------------
coreboot provides a single general purpose memory allocator: malloc()
The preferred form for passing a size of a struct is the following:
```c
p = malloc(sizeof(*p));
```
The alternative form where struct name is spelled out hurts readability
and introduces an opportunity for a bug when the pointer variable type
is changed but the corresponding sizeof that is passed to a memory
allocator is not.
Casting the return value which is a void pointer is redundant. The
conversion from void pointer to any other pointer type is guaranteed by
the C programming language.
You should contain your memory usage to stack variables whenever
possible. Only use malloc() as a last resort. In ramstage, you may also
be able to get away with using static variables. Never use malloc()
outside of ramstage.
Since coreboot only runs for a very short time, there is no memory
deallocator, although a corresponding free() is offered. It is a no-op.
Use of free() is not required though it is accepted. It is useful when
sharing code with other codebases that make use of free().
The inline disease
------------------
There appears to be a common misperception that gcc has a magic "make
me faster" speedup option called "inline". While the use of inlines
can be appropriate (for example as a means of replacing macros, see
Chapter 12), it very often is not. Abundant use of the inline keyword
leads to a much bigger kernel, which in turn slows the system as a whole
down, due to a bigger icache footprint for the CPU and simply because
there is less memory available for the pagecache. Just think about it; a
pagecache miss causes a disk seek, which easily takes 5 milliseconds.
There are a LOT of cpu cycles that can go into these 5 milliseconds.
A reasonable rule of thumb is to not put inline at functions that have
more than 3 lines of code in them. An exception to this rule are the
cases where a parameter is known to be a compiletime constant, and as a
result of this constantness you *know* the compiler will be able to
optimize most of your function away at compile time. For a good example
of this later case, see the kmalloc() inline function.
Often people argue that adding inline to functions that are static and
used only once is always a win since there is no space tradeoff. While
this is technically correct, gcc is capable of inlining these
automatically without help, and the maintenance issue of removing the
inline when a second user appears outweighs the potential value of the
hint that tells gcc to do something it would have done anyway.
Function return values and names
--------------------------------
Functions can return values of many different kinds, and one of the most
common is a value indicating whether the function succeeded or failed.
Such a value can be represented as an error-code integer (-Exxx =
failure, 0 = success) or a "succeeded" boolean (0 = failure, non-zero
= success).
Mixing up these two sorts of representations is a fertile source of
difficult-to-find bugs. If the C language included a strong distinction
between integers and booleans then the compiler would find these
mistakes for us... but it doesn't. To help prevent such bugs, always
follow this convention:
If the name of a function is an action or an imperative command,
the function should return an error-code integer.  If the name
is a predicate, the function should return a "succeeded" boolean.
For example, "add work" is a command, and the add_work() function
returns 0 for success or -EBUSY for failure. In the same way, "PCI
device present" is a predicate, and the pci_dev_present() function
returns 1 if it succeeds in finding a matching device or 0 if it
doesn't.
All EXPORTed functions must respect this convention, and so should all
public functions. Private (static) functions need not, but it is
recommended that they do.
Functions whose return value is the actual result of a computation,
rather than an indication of whether the computation succeeded, are not
subject to this rule. Generally they indicate failure by returning some
out-of-range result. Typical examples would be functions that return
pointers; they use NULL or the ERR_PTR mechanism to report failure.
Don't re-invent the kernel macros
----------------------------------
The header file include/linux/kernel.h contains a number of macros that
you should use, rather than explicitly coding some variant of them
yourself. For example, if you need to calculate the length of an array,
take advantage of the macro
```c
#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
```
There are also min() and max() macros that do strict type checking if
you need them. Feel free to peruse that header file to see what else is
already defined that you shouldn't reproduce in your code.
Editor modelines and other cruft
--------------------------------
Some editors can interpret configuration information embedded in source
files, indicated with special markers. For example, emacs interprets
lines marked like this:
```
-*- mode: c -*-
```
Or like this:
```
/*
Local Variables:
compile-command: "gcc -DMAGIC_DEBUG_FLAG foo.c"
End:
*/
```
Vim interprets markers that look like this:
```
/* vim:set sw=8 noet */
```
Do not include any of these in source files. People have their own
personal editor configurations, and your source files should not
override them. This includes markers for indentation and mode
configuration. People may use their own custom mode, or may have some
other magic method for making indentation work correctly.
Inline assembly
---------------
In architecture-specific code, you may need to use inline assembly to
interface with CPU or platform functionality. Don't hesitate to do so
when necessary. However, don't use inline assembly gratuitously when C
can do the job. You can and should poke hardware from C when possible.
Consider writing simple helper functions that wrap common bits of inline
assembly, rather than repeatedly writing them with slight variations.
Remember that inline assembly can use C parameters.
Large, non-trivial assembly functions should go in .S files, with
corresponding C prototypes defined in C header files. The C prototypes
for assembly functions should use "asmlinkage".
You may need to mark your asm statement as volatile, to prevent GCC from
removing it if GCC doesn't notice any side effects. You don't always
need to do so, though, and doing so unnecessarily can limit
optimization.
When writing a single inline assembly statement containing multiple
instructions, put each instruction on a separate line in a separate
quoted string, and end each string except the last with nt to
properly indent the next instruction in the assembly output:
```c
asm ("magic %reg1, #42nt"
"more_magic %reg2, %reg3"
: /* outputs */ : /* inputs */ : /* clobbers */);
```
References
----------
The C Programming Language, Second Edition by Brian W. Kernighan and
Dennis M. Ritchie. Prentice Hall, Inc., 1988. ISBN 0-13-110362-8
(paperback), 0-13-110370-9 (hardback). URL:
<http://cm.bell-labs.com/cm/cs/cbook/>
The Practice of Programming by Brian W. Kernighan and Rob Pike.
Addison-Wesley, Inc., 1999. ISBN 0-201-61586-X. URL:
<http://cm.bell-labs.com/cm/cs/tpop/>
GNU manuals - where in compliance with K&R and this text - for cpp, gcc,
gcc internals and indent, all available from
<http://www.gnu.org/manual/>
WG14 is the international standardization working group for the
programming language C, URL: <http://www.open-std.org/JTC1/SC22/WG14/>
Kernel CodingStyle, by greg@kroah.com at OLS 2002:
<http://www.kroah.com/linux/talks/ols_2002_kernel_codingstyle_talk/html/>

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@@ -1,118 +0,0 @@
# Code of Conduct
This code of conduct outlines our rules and expectations for everybody
participating in the coreboot community.
## coreboot community etiquette
We have a friendly and productive atmosphere on our mailing lists,
development / code review tools, IRC chat rooms and when we meet in
person. Our principles evolve around the following:
* It's not the user's fault if something goes wrong.
* Attempt collaboration before conflict.
* People who intentionally insult others (users, developers, corporations,
other projects, or the coreboot project itself) will be dealt with. See
policy below.
* We are dealing with hardware with lots of undocumented pitfalls. It is quite
possible that you did everything right, but coreboot or its tools still
won't work for you.
Refrain from insulting anyone or the group they belong to. Remember that
people might be sensitive to other things than you are.
Most of our community members are not native English speakers, thus
misunderstandings can (and do) happen. Assume that others are friendly
and may have picked less-than-stellar wording by accident as long as
you possibly can.
## Reporting Issues
If you have a grievance due to conduct in this community, we're sorry
that you have had a bad experience, and we want to hear about it so
we can resolve the situation.
Please contact members of our arbitration team (listed below) promptly
and directly, in person (if available) or by email: They will listen
to you and react in a timely fashion.
If you feel uncomfortable, please don't wait it out, ask for help,
so we can work on setting things right.
For transparency there is no alias or private mailing list address for
you to reach out to, since we want to make sure that you know who will
and who won't read your message.
However since people might be on travel or otherwise be unavailable
at times, please reach out to multiple persons at once, especially
when using email.
The team will treat your messages confidential as far as the law permits.
For the purpose of knowing what law applies, the list provides the usual
country of residence of each team member.
## Unacceptable Behavior
Unacceptable behaviors include: intimidating, harassing, abusive,
discriminatory, derogatory or demeaning speech or actions by any
participant in our community online, at all related events and in
one-on-one communications carried out in the context of community
business. Community event venues may be shared with members of the public;
please be respectful to all patrons of these locations.
Examples of behaviors we do not accept in our community:
* harmful or prejudicial verbal or written comments related to gender,
sexual orientation, race, religion, disability;
* inappropriate physical contact, and unwelcome sexual advances;
* deliberate intimidation, stalking or following;
* harassing photography or recording;
* sustained disruption of talks or other events.
Using this code of conduct aggressively against other people in the
community might also be harassment. Be considerate when enforcing the code
of conduct and always try to listen to both sides before passing judgment.
## Consequences of Unacceptable Behavior
Unacceptable behavior from any community member, including sponsors and
those with decision-making authority, will not be tolerated.
Anyone asked to stop unacceptable behavior is expected to comply
immediately.
If a community member engages in unacceptable behavior, the community
organizers may take any action they deem appropriate, up to and including
a temporary ban or permanent expulsion from the community without warning
(and without refund in the case of a paid event).
Community organizers can be members of the arbitration team, or organizers
of events and online communities.
## Addressing Grievances
If you feel you have been falsely or unfairly accused of violating this
Code of Conduct, you should notify the arbitration team with a concise
description of your grievance.
## Scope
We expect all community participants (contributors, paid or otherwise;
sponsors; and other guests) to abide by this Code of Conduct in all
community venues, online and in-person, as well as in all one-on-one
communications pertaining to community business.
## Contact info
Our arbitration team consists of the following people
* Stefan Reinauer <stefan.reinauer@coreboot.org> (USA)
* Patrick Georgi <patrick@coreboot.org> (Germany)
* Ronald Minnich <rminnich@coreboot.org> (USA)
* Martin Roth <martin@coreboot.org> (USA)
## License and attribution
This Code of Conduct is distributed under
a [Creative Commons Attribution-ShareAlike
license](http://creativecommons.org/licenses/by-sa/3.0/). It is based
on the [Citizen Code of Conduct](http://citizencodeofconduct.org/)

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@@ -1,70 +0,0 @@
# Conferences
The coreboot community is present at a number of conferences over the year,
usually at [FOSDEM](https://fosdem.org), [OSFC](https://osfc.io), and the
[Chaos Communication Congress](https://events.ccc.de/congress/).
The kind of presence differs, but there's usually a booth or other kind of
gathering where everybody is welcome to say hello and to learn more about
coreboot.
Depending on the nature of the conference, coreboot developers might bring
their development kit with them and conduct development sessions.
## Talks
[Open Source Firmware at Facebook](https://fosdem.org/2019/schedule/event/open_source_firmware_at_facebook/) by [David Hendricks](https://github.com/dhendrix) and [Andrea Barberio](https://github.com/insomniacslk) at [FOSDEM 2019](https://fosdem.org/2019/) ([video](https://video.fosdem.org/2019/K.4.401/open_source_firmware_at_facebook.mp4)) ([slides](https://insomniac.slackware.it/static/2019_fosdem_linuxboot_at_facebook.pdf)) (2019-02-03)
[Open Source Firmware - A love story](https://www.youtube.com/watch?v=xfqKm190dbU) by [Philipp Deppenwiese](https://cybersecurity.9elements.com) at [35c3](https://events.ccc.de/congress/2018)
([slides](https://cdn.media.ccc.de/congress/2018/slides-h264-hd/35c3-9778-deu-eng-Open_Source_Firmware_hd-slides.mp4)) (2018-12-27)
[coreboot mainboard porting with Intel FSP 2.0](https://www.youtube.com/watch?v=qUgo-AVsSCI) by Subrata Banik at OSFC 2018
[A tale of reusability in coreboot](https://www.youtube.com/watch?v=p2bnEYKBDpI) by Furquan Shaikh at OSFC 2018
[How to enable AMD IOMMU in coreboot](https://www.youtube.com/watch?v=5JoEuh9qXx0) by Piotr Król at OSFC 2018
[ARM Trusted Firmware for coreboot developers](https://www.youtube.com/watch?v=UC35q4OJg3k) by Julius Werner at OSFC 2018
[Google Secure Microcontroller and Case Closed Debugging](https://www.youtube.com/watch?v=gC-lbMNmIsg) by Vadim Bendebury at OSFC 2018
[coreboot rompayload](https://www.youtube.com/watch?v=ukSh1n7wjSA) by Ron Minnich at OSFC 2018
[Run upstream coreboot on an ARM Chromebook](https://www.youtube.com/watch?v=N7_9okzPeHo) by Paul Menzel at ECC 2017
[DDR3 memory initialization basics on Intel Sandybrige platforms](https://www.youtube.com/watch?v=h-Lkkg03Erk) by Patrick Rudolph at ECC 2017
[Let's move SMM out of firmware and into the kernel](https://www.youtube.com/watch?v=6GEaw4msq6g) by Ron Minnich at ECC 2017
[SINUMERIK step ahead with coreboot](https://www.youtube.com/watch?v=tq4xSipCWEU) by Werner Zeh at ECC 2017
[Booting UEFI-aware OS on coreboot enabled platform](https://www.youtube.com/watch?v=nt0BkqVUu3w) by Piotr Król and Kamil Wcisło at ECC 2017
[Reverse engineering MT8173 PCM firmwares and ISA for a fully free bootchain](https://www.youtube.com/watch?v=9rKxfo7Gkqo) by Paul Kocialkowski at ECC 2017
[A Tale of six motherboards, two BSDs and coreboot](https://www.youtube.com/watch?v=jlCGzML6zF8) by Piotr Kubaj at ECC 2017
[Enabling TPM 2.0 on coreboot based devices](https://www.youtube.com/watch?v=Yjb9n5p3giI) by Piotr Król and Kamil Wcisło at ECC 2017
[Porting coreboot to the HP ProLiant MicroServer Gen8](https://www.youtube.com/watch?v=BcmUSW2J53k) by Alexander Couzens and Felix Held at ECC 2017
[Implementing coreboot in a ground breaking secure system: ORWL](https://www.youtube.com/watch?v=D4oQjcP6AVI) by Wim Vervoorn and Gerard Duynisveld at ECC 2017
[Buying trustworthy hardware for federal agencies: How open source firmware saves the day](https://www.youtube.com/watch?v=DG_wfaw4zl0) by Carl-Daniel Hailfinger at ECC 2017
[Verified Boot: Surviving in the Internet of Insecure Things: Randall Spangler](https://www.youtube.com/watch?v=4EvTcfcYfMY) by Randall Spangler at coreboot conference 2016
[coreboot on RISC-V](https://www.youtube.com/watch?v=CDNIWuf1jAk) by Ron Minnich at coreboot conference 2016
[An Open Source Embedded Controller](https://www.youtube.com/watch?v=hQb8waUBVSQ) by Bill Richardson at coreboot conference 2016
[KB9012 EC Firmware Reverse Engineering](https://www.youtube.com/watch?v=B708jdCiW7o) by Paul Kocialkowski at coreboot conference 2016
[coreboot on ARM](https://www.youtube.com/watch?v=z-KpAA4_afs) by Julius Werner at coreboot conference 2016
[Intel FSP 2.0 overview](https://www.youtube.com/watch?v=uzfiTiP9dEM) by Giri Mudusuru and Vincent Zimmer at coreboot conference 2016
[coreboot Internals](https://www.youtube.com/watch?v=7YUXr1MH9d4) by Aaron Durbin at coreboot conference 2016
[Skylake FSP to coreboot integration overview](https://www.youtube.com/watch?v=SpL8LbquSVs) by Robbie Zhang at coreboot conference 2016
[S3 implementation on Braswell](https://www.youtube.com/watch?v=GfwTijFnFl0) by Hannah Williams at coreboot conference 2016

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@@ -1,18 +0,0 @@
# Our forums
The coreboot community has various venues to help each other and discuss the
direction of our project.
## Mailing list
The first address for coreboot related discussion is our mailing list.
You can subscribe on its
[information page](https://mail.coreboot.org/postorius/lists/coreboot.coreboot.org/) and
read its
[archives](https://mail.coreboot.org/hyperkitty/list/coreboot@coreboot.org/).
## IRC
We also have a
[real time chat](https://webchat.freenode.net?channels=%23coreboot)
on the Freenode IRC network's #coreboot channel.

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@@ -1,45 +0,0 @@
# Accounts on coreboot.org
There are a number of places where you can benefit from creaating an account
in our community. Since there is no single sign-on system in place (at this
time), they come with their own setup routines.
## Gerrit code review
We exchange and review patches to the code using our [Gerrit code review
system](https://review.coreboot.org).
It allows logging in with a Google or GitHub account using OAuth2 as well
as with any OpenID provider that you may already use.
On the [settings screen](https://review.coreboot.org/settings) you can register
all your email addresses you intend to use in the context of coreboot
development so that commits with your email address in them are associated with
you properly.
### https push access
When using the https URLs to git repositories, you can push with the "HTTP
Credentials" you can have Gerrit generate for you on that page. By default,
git uses `$HOME/.netrc` for http authentication data, so add a line there
stating:
machine review.coreboot.org login $your-user-name password $your-password
### Gerrit user avatar
To setup an avatar to show in Gerrit, clone the avatars repository at
https://review.coreboot.org/gerrit-avatars.git and add a file named
$your-user-ID.jpg (the user ID is a number shown on the [settings screen](https://review.coreboot.org/settings)).
The image must be provided in JPEG format, must be square and have at most 50000
bytes.
After you push for review, the system will automatically verify your change
and, if adhering to these constraints, approve it. You can then immediately
submit it.
## Issue tracker
We have an [issue tracker](https://ticket.coreboot.org) that is used for
coreboot and related code, such as libpayload, as well as for the project's
infrastructure.
It can be helpful to refer to issues we track there in commit messages:
Fixes: https://ticket.coreboot.org/issues/$id

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@@ -1,6 +1,4 @@
# -*- coding: utf-8 -*-
import subprocess
from recommonmark.parser import CommonMarkParser
# Add any paths that contain templates here, relative to this directory.
templates_path = ['_templates']
@@ -13,17 +11,17 @@ master_doc = 'index'
# General information about the project.
project = u'coreboot'
copyright = u'CC-by 4.0 the coreboot project'
copyright = u'the coreboot project'
author = u'the coreboot project'
# The version info for the project you're documenting, acts as replacement for
# |version| and |release|, also used in various other places throughout the
# built documents.
#
# The full version, including alpha/beta/rc tags.
release = subprocess.check_output(('git', 'describe')).decode("utf-8")
# The short X.Y version.
version = release.split("-")[0]
version = u'4.7'
# The full version, including alpha/beta/rc tags.
release = u'4.7' # TODO: use 'git describe'
# The language for content autogenerated by Sphinx. Refer to documentation
# for a list of supported languages.
@@ -121,7 +119,7 @@ latex_documents = [
#
# latex_appendices = []
# If false, will not define \strong, \code, itleref, \crossref ... but only
# It false, will not define \strong, \code, itleref, \crossref ... but only
# \sphinxstrong, ..., \sphinxtitleref, ... To help avoid clash with user added
# packages.
#
@@ -157,14 +155,9 @@ texinfo_documents = [
'Miscellaneous'),
]
enable_auto_toc_tree = True
class MyCommonMarkParser(CommonMarkParser):
# remove this hack once upsteam RecommonMark supports inline code
def visit_code(self, mdnode):
from docutils import nodes
n = nodes.literal(mdnode.literal, mdnode.literal)
self.current_node.append(n)
source_parsers = {
'.md': 'recommonmark.parser.CommonMarkParser',
}
# Documents to append as an appendix to all manuals.
#
@@ -182,14 +175,14 @@ class MyCommonMarkParser(CommonMarkParser):
#
# texinfo_no_detailmenu = False
enable_auto_toc_tree = True
def setup(app):
from recommonmark.transform import AutoStructify
app.add_source_parser('.md', MyCommonMarkParser)
app.add_config_value('recommonmark_config', {
'enable_auto_toc_tree': True,
'enable_auto_doc_ref': False, # broken in Sphinx 1.6+
'enable_auto_doc_ref': True,
'enable_eval_rst': True,
'url_resolver': lambda url: '/' + url
}, True)

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@@ -1,203 +0,0 @@
# Project Ideas
This section collects ideas to improve coreboot and related projects and
should serve as a pool of ideas for people who want to enter the field
of firmware development but need some guidance what to work on.
These tasks can be adopted as part of programs like Google Summer of
Code or by motivated individuals outside such programs.
Each entry should outline what would be done, the benefit it brings
to the project, the pre-requisites, both in knowledge and parts. They
should also list people interested in supporting people who want to work
on them - since we started building this list for Google Summer of Code,
we'll adopt its term for those people and call them mentors.
The requirements for each project aim for productive work on the project,
but it's always possible to learn them "on the job". If you have any
doubt if you can bring yourself up to speed in a required time frame
(e.g. for GSoC), feel free to ask in the community or the mentors listed
with the projects. We can then try together to figure out if you're a
good match for a project, even when requirements might not all be met.
## Provide toolchain binaries
Our crossgcc subproject provides a uniform compiler environment for
working on coreboot and related projects. Sadly, building it takes hours,
which is a bad experience when trying to build coreboot the first time.
Provide packages/installers of our compiler toolchain for Linux distros,
Windows, Mac OS. For Windows, this should also include the environment
(shell, make, ...).
The scripts to generate these packages should be usable on a Linux
host, as that's what we're using for our automated build testing system
that we could extend to provide current packages going forward. This
might include automating some virtualization system (eg. QEMU or CrosVM) for
non-Linux builds or Docker for different Linux distributions.
### Requirements
* coreboot knowledge: Should know how to build coreboot images and where
the compiler comes into play in our build system.
* other knowledge: Should know how packages or installers for their
target OS work. Knowledge of the GCC build system is a big plus
* hardware requirements: Nothing special
### Mentors
* Patrick Georgi <patrick@georgi.software>
## Support Power9/Power8 in coreboot
There are some basic PPC64 stubs in coreboot, and there's open hardware
in TALOS2 and its family. While they already have fully open source
firmware, coreboot support adds a unified story for minimal firmware
across architectures.
### Requirements
* coreboot knowledge: Should be familiar with making chipset level
changes to the code.
* other knowledge: A general idea of the Power architecture, the more,
the better
* hardware requirements: QEMU Power bring-up exists, and even if it
probably needs to be fixed up, that shouldn't be an exceedingly large
task. For everything else, access to real Power8/9 hardware and recovery
tools (e.g. for external flashing) is required.
### Mentors
* Timothy Pearson <tpearson@raptorengineering.com>
## Support QEMU AArch64 or MIPS
Having QEMU support for the architectures coreboot can boot helps with
some (limited) compatibility testing: While QEMU generally doesn't need
much hardware init, any CPU state changes in the boot flow will likely
be quite close to reality.
That could be used as a baseline to ensure that changes to architecture
code doesn't entirely break these architectures
### Requirements
* coreboot knowledge: Should know the general boot flow in coreboot.
* other knowledge: This will require knowing how the architecture
typically boots, to adapt the coreboot payload interface to be
appropriate and, for example, provide a device tree in the platform's
typical format.
* hardware requirements: since QEMU runs practically everywhere and
needs no recovery mechanism, these are suitable projects when no special
hardware is available.
### Mentors
* Patrick Georgi <patrick@georgi.software>
## Add Kernel Address Sanitizer functionality to coreboot
The Kernel Address Sanitizer (KASAN) is a runtime dynamic memory error detector.
The idea is to check every memory access (variables) for its validity
during runtime and find bugs like stack overflow or out-of-bounds accesses.
Implementing this stub into coreboot like "Undefined behavior sanitizer support"
would help to ensure code quality and make the runtime code more robust.
### Requirements
* knowledge in the coreboot build system and the concept of stages
* the KASAN feature can be improved in a way so that the memory space needed
during runtime is not on a fixed address provided during compile time but
determined during runtime. For this to achieve a small patch to the GCC will
be helpful. Therefore minor GCC knowledge would be beneficial.
* Implementation can be initially done in QEMU and improved on different
mainboards and platforms
### Mentors
* Werner Zeh <werner.zeh@gmx.net>
## Port payloads to ARM, AArch64, MIPS or RISC-V
While we have a rather big set of payloads for x86 based platforms, all other
architectures are rather limited. Improve the situation by porting a payload
to one of the platforms, for example GRUB2, U-Boot (the UI part), Tianocore,
yabits, FILO, or Linux-as-Payload.
Since this is a bit of a catch-all idea, an application to GSoC should pick a
combination of payload and architecture to support.
### Requirements
* coreboot knowledge: Should know the general boot flow in coreboot
* other knowledge: It helps to be familiar with the architecture you want to
work on.
* hardware requirements: Much of this can be done in QEMU or other emulators,
but the ability to test on real hardware is a plus.
### Mentors
* Simon Glass <sjg@chromium.org> for U-Boot payload projects
## Fully support building coreboot with the Clang compiler
Most coreboot code is written in C, and it would be useful to support
a second compiler suite in addition to gcc. Clang is another popular
compiler suite and the build system generally supports building coreboot
with it, but firmware is a rather special situation and we need to
adjust coreboot and Clang some more to get usable binaries out of that
combination.
The goal would be to get the emulation targets to boot reliably first,
but also to support real hardware. If you don't have hardware around,
you likely will find willing testers for devices they own and work from
their bug reports.
### Requirements
* coreboot knowledge: Have a general concept of the build system
* Clang knowledge: It may be necessary to apply minor modifications to Clang
itself, but at least there will be Clang-specific compiler options etc to
adapt, so some idea how compilers work and how to modify their behavior is
helpful.
* hardware requirements: If you have your own hardware that is already
supported by coreboot that can be a good test target, but you will debug
other people's hardware, too.
* debugging experience: It helps if you know how to get the most out of a bug
report, generate theories, build patches to test them and figure out what's
going on from the resulting logs.
### Mentors
* Patrick Georgi <patrick@georgi.software>
## Make coreboot coverity clean
coreboot and several other of our projects are automatically tested
using Synopsys' free "Coverity Scan" service. While some fare pretty
good, like [em100](https://scan.coverity.com/projects/em100) at 0 known
defects, there are still many open issues in other projects, most notably
[coreboot](https://scan.coverity.com/projects/coreboot) itself (which
is also the largest codebase).
Not all of the reports are actual issues, but the project benefits a
lot if the list of unhandled reports is down to 0 because that provides
a baseline when future changes reintroduce new issues: it's easier to
triage and handle a list of 5 issues rather than more than 350.
This project would be going through all reports and handling them
appropriately: Figure out if reports are valid or not and mark them
as such. For valid reports, provide patches to fix the underlying issue.
### Mentors
* Patrick Georgi <patrick@georgi.software>
## Extend Ghidra to support analysis of firmware images
[Ghidra](https://ghidra-sre.org) is a recently released cross-platform
disassembler and decompiler that is extensible through plugins. Make it
useful for firmware related work: Automatically parse formats (eg. by
integrating UEFITool, cbfstool, decompressors), automatically identify
16/32/64bit code on x86/amd64, etc.
## Learn hardware behavior from I/O and memory access logs
[SerialICE](https://www.serialice.com) is a tool to trace the behavior of
executable code like firmware images. One result of that is a long log file
containing the accesses to hardware resources.
It would be useful to have a tool that assists a developer-analyst in deriving
knowledge about hardware from such logs. This likely can't be entirely
automatic, but a tool that finds patterns and can propagate them across the
log (incrementially raising the log from plain I/O accesses to a high-level
description of driver behavior) would be of great use.
This is a research-heavy project.
### Requirements
* Driver knowledge: Somebody working on this should be familiar with
how hardware works (eg. MMIO based register access, index/data port
accesses) and how to read data sheets.
* Machine Learning: ML techniques may be useful to find structure in traces.
### Mentors
* Ron Minnich <rminnich@google.com>

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# Distributions
coreboot doesn't provide binaries but provides a toolbox that others can use
to build boot firmware for all kinds of purposes. These third-parties can be
broadly separated in two groups: Those shipping coreboot on their hardware,
and those providing after-market firmware to extend the usefulness of devices.
## Hardware shipping with coreboot
### Purism
[Purism](https://www.puri.sm) sells laptops with a focus on user privacy and
security; part of that effort is to minimize the amount of proprietary and/or
binary code. Their laptops ship with a blob-free OS and coreboot firmware
with a neutralized Intel Management Engine (ME) and SeaBIOS as the payload.
### ChromeOS Devices
All ChromeOS devices ([Chromebooks](https://chromebookdb.com/), Chromeboxes,
Chromebit, etc) released from 2012 onward use coreboot for their main system
firmware. Additionally, starting with the 2013 Chromebook Pixel, the firmware
running on the Embedded Controller (EC - a small microcontroller which provides
functions like battery management, keyboard support, and sensor interfacing)
is open source as well.
### Libretrend
[Libretrend](https://libretrend.com) sells the Librebox, a NUC-like PC which
ships with coreboot firmware.
### PC Engines APUs
[PC Engines](https://pcengines.ch) designs and sells embedded PC hardware that
ships with coreboot and support upstream maintenance for the devices through a
third party, [3mdeb](https://3mdeb.com). They provide current and tested
firmware binaries on [GitHub](https://pcengines.github.io).
## After-market firmware
### Libreboot
[Libreboot](https://libreboot.org) is a downstream coreboot distribution that
provides ready-made firmware images for supported devices: those which can be
built entirely from source code. Their copy of the coreboot repository is
therefore stripped of all devices that require binary components to boot.
### MrChromebox
[MrChromebox](https://mrchromebox.tech/) provides upstream coreboot firmware
images for the vast majority of x86-based Chromebooks and Chromeboxes, using
Tianocore as the payload to provide a modern UEFI bootloader. Why replace
coreboot with coreboot? Mr Chromebox's images are built using upstream
coreboot (vs Google's older, static tree/branch), include many features and
fixes not found in the stock firmware, and offer much broader OS compatibility
(i.e., they run Windows as well as Linux). They also offer updated CPU
microcode, as well as firmware updates for the device's embedded controller
(EC). This firmware "takes the training wheels off" your ChromeOS device :)
### Heads
[Heads](http://osresearch.net) is an open source custom firmware and OS
configuration for laptops and servers that aims to provide slightly better
physical security and protection for data on the system. Unlike
[Tails](https://tails.boum.org/), which aims to be a stateless OS that leaves
no trace on the computer of its presence, Heads is intended for the case where
you need to store data and state on the computer.
Heads is not just another Linux distribution it combines physical hardening
of specific hardware platforms and flash security features with custom coreboot
firmware and a Linux boot loader in ROM.
### Skulls
[Skulls](https://github.com/merge/skulls) provides firmware images for
laptops like the Lenovo Thinkpad X230. It uses upstream coreboot, an easy
to use payload like SeaBIOS and Intel's latest microcode update.
It simplifies installation and includes compact documentation. Skulls also
enables easy switching to [Heads](#heads) and back.

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@@ -1,7 +0,0 @@
# Platform independent drivers documentation
The drivers can be found in `src/drivers`. They are intended for onboard
and plugin devices, significantly reducing integration complexity and
they allow to easily reuse existing code accross platforms.
* [IPMI KCS](ipmi_kcs.md)

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@@ -1,47 +0,0 @@
# IPMI KCS driver
The driver can be found in `src/drivers/ipmi/`. It works with BMC that provide
a KCS I/O interface as specified in the [IPMI] standard.
The driver detects the IPMI version, reserves the I/O space in coreboot's
resource allocator and writes the required ACPI and SMBIOS tables.
## For developers
To use the driver, select the `IPMI_KCS` Kconfig and add the following PNP
device under the LPC bridge device (in example for the KCS at 0xca2):
```
chip drivers/ipmi
device pnp ca2.0 on end # IPMI KCS
end
```
**Note:** The I/O base address needs to be aligned to 2.
The following registers can be set:
* `have_nv_storage`
* Boolean
* If true `nv_storage_device_address` will be added to SMBIOS type 38.
* `nv_storage_device_address`
* Integer
* The NV storage address as defined in SMBIOS spec for type 38.
* `bmc_i2c_address`
* Integer
* The i2c address of the BMC. zero if not applicable.
* `have_apic`
* Boolean
* If true the `apic_interrupt` will be added to SPMI table.
* `apic_interrupt`
* Integer
* The APIC interrupt used to notify about a change on the KCS.
* `have_gpe`
* Boolean
* If true the `gpe_interrupt` will be added to SPMI table.
* `gpe_interrupt`
* Integer
* The bit in GPE (SCI) used to notify about a change on the KCS.
[IPMI]: https://www.intel.com/content/dam/www/public/us/en/documents/product-briefs/ipmi-second-gen-interface-spec-v2-rev1-1.pdf

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@@ -1,28 +0,0 @@
# Flashing firmware externally supplying direct power
**WARNING:** Never use a high current rated power supply, like PC ATX power
supply. It'll literally melt your PCB traces on short circuit.
On some mainboards the flash IC Vcc pin is connected to a diode, which prevents
powering the rest of the board.
![][flash_ic_diode]
Please have a look at the mainboard specific documentation for details.
On those boards it's safe to use a programmer and supply power externally.
**WARNING:** Verify that you apply the correct voltage!
## USB programmer
USB programmers are usually current limited by the host USB hub. On USB 2.0
ports the limit is 500mA, which is sufficient to power the flash. Those are
the best choice as they are stateless and have a fast power on reset cycle.
## Single board computers (like BeagleBone Black / RPi)
Be careful when connecting a flash chip, especially when using a Pomona
test-clip. A short circuit or overcurrent (250mA) causes a brown-out reset,
resulting in a reboot of the running operating system (and possible loss of
remote shell).
[flash_ic_diode]: flash_ic_diode.svg

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@@ -1,23 +0,0 @@
# Flashing firmware standalone
If none of the other methods work, there are three possibilities:
## Desolder
You must remove or desolder the flash IC before you can flash it.
It's recommended to solder a socket in place of the flash IC.
When flashing the IC, always connect all input pins.
If in doubt, pull /WP, /HOLD, /RESET and alike up towards Vcc.
## SPI flash emulator
If you are a developer, you might want to use an [EM100Pro] instead, which sets
the onboard flash on hold, and allows to run custom firmware.
It provides a very fast development cycle without actually writing to flash.
## SPI flash overwrite
It is possible to set the onboard flash on hold and use another flash chip.
Connect all lines one-to-one, except /HOLD. Pull /HOLD of the soldered flash IC
low, and /HOLD of your replacement flash IC high.
[EM100Pro]: https://www.dediprog.com/product/EM100Pro

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# Flashing firmware tutorial
Updating the firmware is possible using the **internal method**, where the updates
happen from a running system, or using the **external method**, where the system
is in a shut down state and an external programmer is attached to write into the
flash IC.
## Contents
* [Flashing internaly](int_flashrom.md)
* [Flashing firmware standalone](ext_standalone.md)
* [Flashing firmware externally supplying direct power](ext_power.md)
* [Flashing firmware externally without supplying direct power](no_ext_power.md)
## General advice
* It's recommended to only flash the BIOS region.
* Always verify the firmware image.
* If you flash externally and have transmission errors:
* Use short wires
* Reduce clock frequency
* Check power supply
* Make sure that there are no other bus masters (EC, ME, SoC, ...)
## Internal method
This method using [flashrom] is available on many platforms, as long as they
aren't locked down.
There are various protection schemes that make it impossible to modify or
replace a firmware from a running system. coreboot allows to disable these
mechanisms, making it possible to overwrite (or update) the firmware from a
running system.
Usually you must use the **external method** once to install a retrofitted
coreboot and then you can use the **internal method** for future updates.
There are multiple ways to update the firmware:
* Using flashrom's *internal* programmer to directly write into the firmware
flash IC, running on the target machine itself
* A proprietary software to update the firmware, running on the target machine
itself
* A UEFI firmware update capsule
More details on flashrom's
* [internal programmer](int_flashrom.md)
## External method
External flashing is possible on many platforms, but requires disassembling
the target hardware. You need to buy a flash programmer, that
exposes the same interface as your flash IC (likely SPI).
Please also have a look at the mainboard-specific documentation for details.
After exposing the firmware flash IC, read the schematics and use one of the
possible methods:
* [Flashing firmware standalone](ext_standalone.md)
* [Flashing firmware externally supplying direct power](ext_power.md)
* [Flashing firmware externally without supplying direct power](no_ext_power.md)
**WARNING:** Using the wrong method or accidentally using the wrong pinout might
permanently damage your hardware!
**WARNING:** Do not rely on dots *painted* on flash ICs to orient the pins!
Any dots painted on flash ICs may only indicate if they've been tested. Dots
that appear in datasheets to indicate pin 1 correspond to some kind of physical
marker, such as a drilled hole, or one side being more flat than the other.
## Using a layout file
On platforms where the flash IC is shared with other components you might want
to write only a part of the flash IC. On Intel for example there are IFD, ME and
GBE which don't need to be updated to install coreboot.
To make [flashrom] only write the *bios* region, leaving Intel ME and Intel IFD
untouched, you can use a layout file, which can be created with ifdtool and a backup
of the original firmware.
```bash
ifdtool -f rom.layout backup.rom
```
and looks similar to:
```
00000000:00000fff fd
00500000:00bfffff bios
00003000:004fffff me
00001000:00002fff gbe
```
By specifying *-l* and *-i* [flashrom] writes a single region:
```bash
flashrom -l rom.layout -i bios -w coreboot.rom -p <programmer>
```
## Using an IFD to determine the layout
flashrom version 1.0 supports reading the layout from the IFD (first 4KiB of
the ROM). You don't need to manually specify a layout it, but it only works
under the following conditions:
* Only available on Intel ICH7+
* There's only one flash IC when flashing externally
```bash
flashrom --ifd -i bios -w coreboot.rom -p <programmer>
```
**TODO** explain FMAP regions, normal/fallback mechanism, flash lock mechanisms
[flashrom]: https://www.flashrom.org/Flashrom

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@@ -1,19 +0,0 @@
# Flashing firmware internally
**WARNING:** If you flash a broken firmware and have no recovery mechanism, you
must use the **external method** to flash a working firmware again.
## Using flashrom
This method does only work on Linux, if it isn't locked down.
You may also need to boot with 'iomem=relaxed' in the kernel command
line if CONFIG_IO_STRICT_DEVMEM is set.
For more details please also check [flashrom's wiki].
Use the programmer *internal* to flash *coreboot.rom* internally:
```bash
flashrom -p internal -w coreboot.rom
```
[flashrom's wiki]: https://www.flashrom.org/Flashrom

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@@ -1,22 +0,0 @@
# Flashing firmware externally supplying no power
On some mainboards the flash IC's Vcc pin is connected to the internal
power-rail, powering the entire board if the flash IC is powered externally.
Likely it powers other chips which access the flash IC, preventing the external
programmer from reading/writing the chip. It also violates the components'
power sequence, bringing the ICs into an undefined state.
![][flash_ic_no_diode]
Please have a look at the mainboard specific documentation for details.
On those boards it's recommended to use a programmer without supplying power
externally.
The key to read and write the flash IC is to put the machine into *S3* sleep-
state or *S5* sleep-state *maybe* with Wake-On-LAN enabled.
Another option that sometimes works is to keep the device in reset. This method requires
knowledge of the board schematics and might require hardware modifications.
Use a multimeter to make sure the flash IC is powered in those sleep states.
[flash_ic_no_diode]: flash_ic_no_diode.svg

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@@ -13,8 +13,8 @@ here, please discuss it in the mailing list to get this document updated.
Don't just assume that it's okay, even if someone on IRC says it is.
Summary
-------
Summary:
--------
These are the expectations for committing, reviewing, and submitting code
into coreboot git and gerrit. While breaking individual rules may not have
immediate consequences, the coreboot leadership may act on repeated or
@@ -33,8 +33,8 @@ addresses.
* Dont submit patches that you know will break other platforms.
More detail
-----------
More detail:
------------
* Don't violate the licenses. If you're submitting code that you didn't
write yourself, make sure the license is compatible with the license of the
project you're submitting the changes to. If youre submitting code that
@@ -46,11 +46,11 @@ clarification, see the Developer's Certificate of Origin in the coreboot
* Let non-trivial patches sit in a review state for at least 24 hours
before submission. Remember that there are coreboot developers in timezones
all over the world, and everyone should have a chance to contribute.
Trivial patches would be things like whitespace changes or spelling fixes,
in general those that dont impact the final binary output. The
Trivial patches would be things like whitespace changes or spelling fixes.
In general, small changes that dont impact the final binary output. The
24-hour period would start at submission, and would be restarted at any
update which significantly changes any part of the patch. Patches can be
'Fast-tracked' and submitted in under 24 hours with the agreement of at
'Fast-tracked' and submitted in under this 24 hour with the agreement of at
least 3 +2 votes.
* Do not +2 patches that you authored or own, even for something as trivial
@@ -98,8 +98,8 @@ must at least provide a path that will allow other platforms to continue
working.
Recommendations for gerrit activity
-----------------------------------
Recommendations for gerrit activity:
------------------------------------
These guidelines are less strict than the ones listed above. These are more
of the “good idea” variety. You are requested to follow the below
guidelines, but there will probably be no actual consequences if theyre
@@ -150,8 +150,8 @@ together so people can easily see the connection at the top level of
gerrit. Topics can be set for individual patches in gerrit by going into
the patch and clicking on the icon next to the topic line. Topics can also
be set when you push the patches into gerrit. For example, to push a set of
commits with the i915-kernel-x60 set, use the command:
git push origin HEAD:refs/for/master%topic=i915-kernel-x60
commits with the the i915-kernel-x60 set, use the command:
git push origin HEAD:refs/for/master/i915-kernel-x60
* If one of your patches isn't ready to be merged, make sure it's obvious
that you don't feel it's ready for merge yet. The preferred way to show
@@ -159,19 +159,15 @@ this is by marking in the commit message that its not ready until X. The
commit message can be updated easily when its ready to be pushed.
Examples of this are "WIP: title" or "[NEEDS_TEST]: title". Another way to
mark the patch as not ready would be to give it a -1 or -2 review, but
isn't as obvious as the commit message. These patches can also be pushed with
the wip flag:
git push origin HEAD:refs/for/master%wip
isn't as obvious as the commit message. These patches can also be pushed as
drafts as shown in the next guideline.
* When pushing patches that are not for submission, these should be marked
as such. This can be done in the title [DONOTSUBMIT], or can be pushed as
private changes, so that only explicitly added reviewers will see them. These
draft commits, so that only explicitly added reviewers will see them. These
sorts of patches are frequently posted as ideas or RFCs for the community
to look at. To push a private change, use the command:
git push origin HEAD:refs/for/master%private
* Multiple push options can be combined:
git push origin HEAD:refs/for/master%private,wip,topic=experiment
to look at. To push a draft, use the command:
git push origin HEAD:refs/drafts/master
* Respond to anyone who has taken the time to review your patches, even if
it's just to say that you disagree. While it may seem annoying to address a
@@ -255,8 +251,8 @@ The script 'util/gitconfig/rebase.sh' can be used to help automate this.
Other tags such as 'Commit-Queue' can simply be removed.
Expectations contributors should have
-------------------------------------
Expectations contributors should have:
--------------------------------------
* Don't expect that people will review your patch unless you ask them to.
Adding other people as reviewers is the easiest way. Asking for reviews for
individual patches in the IRC channel, or by sending a direct request to an

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@@ -1,105 +0,0 @@
# coreboot architecture
## Overview
![][architecture]
[architecture]: comparision_coreboot_uefi.svg
## Stages
coreboot consists of multiple stages that are compiled as separate binaries and
are inserted into the CBFS with custom compression. The bootblock usually doesn't
have compression while the ramstage and payload are compressed with LZMA.
Each stage loads the next stage a given address (possibly decompressing it).
Some stages are relocatable and can be placed anywhere in DRAM. Those stages are
usually cached in CBMEM for faster loading times on ACPI S3 resume.
Supported stage compressions:
* none
* LZ4
* LZMA
## bootblock
The bootblock is the first stage executed after CPU reset. It is written in
assembly language and its main task is to set up everything for a C-environment:
Common tasks:
* Cache-As-RAM for heap and stack
* Set stack pointer
* Clear memory for BSS
* Decompress and load the next stage
On x86 platforms that includes:
* Microcode updates
* Timer init
* Switching from 16-bit real-mode to 32-bit protected mode
The bootblock loads the romstage or the verstage if verified boot is enabled.
### Cache-As-Ram
The *Cache-As-Ram*, also called Non-Eviction mode, or *CAR* allows to use the
CPU cache like regular SRAM. This is particullary usefull for high level
languages like `C`, which need RAM for heap and stack.
The CAR needs to be activated using vendor specific CPU instructions.
The following stages run when Cache-As-Ram is active:
* bootblock
* romstage
* verstage
* postcar
## verstage
The verstage is where the root-of-trust starts. It's assumed that
it cannot be overwritten in-field (together with the public key) and
it starts at the very beginning of the boot process.
The verstage installs a hook to verify a file before it's loaded from
CBFS or a partition before it's accessed.
The verified boot mechanism allows trusted in-field firmware updates
combined with a fail-safe recovery mode.
## romstage
The romstage initializes the DRAM and prepares everything for device init.
Common tasks:
* Early device init
* DRAM init
## postcar
To leave the CAR setup and run code from regular DRAM the postcar-stage tears
down CAR and loads the ramstage. Compared to other stages it's minimal in size.
## ramstage
The ramstage does the main device init:
* PCI device init
* On-chip device init
* TPM init (if not done by verstage)
* Graphics init (optional)
* CPU init (like set up SMM)
After initialization tables are written to inform the payload or operating system
about the current hardware existance and state. That includes:
* ACPI tables (x86 specific)
* SMBIOS tables (x86 specific)
* coreboot tables
* devicetree updates (ARM specific)
It also does hardware and firmware lockdown:
* Write-protection of boot media
* Lock security related registers
* Lock SMM mode (x86 specific)
## payload
The payload is the software that is run after coreboot is done. It resides in
the CBFS and there's no possibility to choose it at runtime.
For more details have a look at [payloads](../payloads.md).

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# Getting Started
* [coreboot architecture](architecture.md)
* [Build System](build_system.md)
* [Submodules](submodules.md)
* [Kconfig](kconfig.md)
* [Gerrit Guidelines](gerrit_guidelines.md)
* [Documentation License](license.md)
* [Writing Documentation](writing_documentation.md)

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# coreboot documentation license
Files under Documentation/ are licensed under CC-BY 4.0 terms, printed below.
As an exception, files under Documentation/ with a history older than 2017-05-24
might be under different licenses (but should be cleared up ASAP).
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b. __To the extent possible, in no event will the Licensor be liable to You on any legal theory (including, without limitation, negligence) or otherwise for any direct, special, indirect, incidental, consequential, punitive, exemplary, or other losses, costs, expenses, or damages arising out of this Public License or use of the Licensed Material, even if the Licensor has been advised of the possibility of such losses, costs, expenses, or damages. Where a limitation of liability is not allowed in full or in part, this limitation may not apply to You.__
c. The disclaimer of warranties and limitation of liability provided above shall be interpreted in a manner that, to the extent possible, most closely approximates an absolute disclaimer and waiver of all liability.
### Section 6 Term and Termination.
a. This Public License applies for the term of the Copyright and Similar Rights licensed here. However, if You fail to comply with this Public License, then Your rights under this Public License terminate automatically.
b. Where Your right to use the Licensed Material has terminated under Section 6(a), it reinstates:
1. automatically as of the date the violation is cured, provided it is cured within 30 days of Your discovery of the violation; or
2. upon express reinstatement by the Licensor.
For the avoidance of doubt, this Section 6(b) does not affect any right the Licensor may have to seek remedies for Your violations of this Public License.
c. For the avoidance of doubt, the Licensor may also offer the Licensed Material under separate terms or conditions or stop distributing the Licensed Material at any time; however, doing so will not terminate this Public License.
d. Sections 1, 5, 6, 7, and 8 survive termination of this Public License.
### Section 7 Other Terms and Conditions.
a. The Licensor shall not be bound by any additional or different terms or conditions communicated by You unless expressly agreed.
b. Any arrangements, understandings, or agreements regarding the Licensed Material not stated herein are separate from and independent of the terms and conditions of this Public License.
### Section 8 Interpretation.
a. For the avoidance of doubt, this Public License does not, and shall not be interpreted to, reduce, limit, restrict, or impose conditions on any use of the Licensed Material that could lawfully be made without permission under this Public License.
b. To the extent possible, if any provision of this Public License is deemed unenforceable, it shall be automatically reformed to the minimum extent necessary to make it enforceable. If the provision cannot be reformed, it shall be severed from this Public License without affecting the enforceability of the remaining terms and conditions.
c. No term or condition of this Public License will be waived and no failure to comply consented to unless expressly agreed to by the Licensor.
d. Nothing in this Public License constitutes or may be interpreted as a limitation upon, or waiver of, any privileges and immunities that apply to the Licensor or You, including from the legal processes of any jurisdiction or authority.
> Creative Commons is not a party to its public licenses. Notwithstanding, Creative Commons may elect to apply one of its public licenses to material it publishes and in those instances will be considered the “Licensor.” Except for the limited purpose of indicating that material is shared under a Creative Commons public license or as otherwise permitted by the Creative Commons policies published at [creativecommons.org/policies](http://creativecommons.org/policies), Creative Commons does not authorize the use of the trademark “Creative Commons” or any other trademark or logo of Creative Commons without its prior written consent including, without limitation, in connection with any unauthorized modifications to any of its public licenses or any other arrangements, understandings, or agreements concerning use of licensed material. For the avoidance of doubt, this paragraph does not form part of the public licenses.
>
> Creative Commons may be contacted at creativecommons.org

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@@ -1,146 +0,0 @@
# coreboot documentation guidelines
> Documentation is like sex: when it is good, it is very, very good;
> and when it is bad, it is better than nothing.
That said please always try to write documentation! One problem in the
firmware development is the missing documentation. In this document
you will get a brief introduction how to write, submit and publish
documenation to coreboot.
## Preparations
coreboot uses [Sphinx] documentation tool. We prefer the markdown format
over reStructuredText so only embedded ReST is supported. Checkout the
[Markdown Guide] for more information.
### option 1: Use the docker image
The easiest way to build the documentation is using a docker image.
To build the image run the following in the base directory:
make -C util/docker/ doc.coreboot.org
Before building the documentation make sure the output directory is given
the correct permissions before running docker.
mkdir -p Documentation/_build
To build the documentation:
make -C util/docker docker-build-docs
To have the documentation build and served over a web server live run:
make -C util/docker docker-livehtml-docs
On the host machine, open a browser to the address <http://0.0.0.0:8000>.
### option 2: Install Sphinx
Please follow this official [guide] to install sphinx.
You will also need python-recommonmark for sphinx to be able to handle
markdown documentation.
The recommended version is sphinx 1.7.7, sphinx_rtd_theme 0.4.1 and
recommonmark 0.4.0.
### Optional
Install [sphinx-autobuild] for rebuilding markdown/rst sources on the fly!
## Basic and simple rules
The following rules should be followed in order to get it at least reviewed
on [review.coreboot.org].
Documentation:
1. Must be written in **markdown** with **embedded reStructuredText**
format.
2. Must be written in **English**.
3. Must be placed into **Documentation/** directory subfolder.
4. Should follow the same directory structure as **src/** when practical.
5. Must be referenced from within other markdown files
6. The commit must follow the [Gerrit Guidelines].
7. Must have all **lowercase filenames**.
8. Running text should have a visible width of about **72 chars**.
9. Should not **duplicate** documentation, but reference it instead.
10. Must not include the same picture in multiple markdown files.
11. Images should be kept small. They should be under 700px in width, as
the current theme doesn't allow bigger images.
12. Shouldn't cover implementation details; for details, the code is the
reference.
## Referencing markdown documents
Starting with Sphinx 1.6 recommonmark's *auto_doc_ref* feature is broken.
To reference documents use the TOC tree or inline RST code.
## Markdown and Tables
Under Sphinx markdown tables are not supported. Therefore you can use following
code block to write tables in reStructuredText and embed them into the markdown:
```eval_rst
+------------+------------+-----------+
| Header 1 | Header 2 | Header 3 |
+============+============+===========+
| body row 1 | column 2 | column 3 |
+------------+------------+-----------+
| body row 2 | Cells may span columns.|
+------------+------------+-----------+
| body row 3 | Cells may | - Cells |
+------------+ span rows. | - contain |
| body row 4 | | - blocks. |
+------------+------------+-----------+
``` #just a code block is enough
## TocTree
To make sure that all documents are included into the final documentation, you
must reference each document from at least one *toctree*. The *toctree* must
only reference files in the same folder or in subfolders !
To create a toctree, simply use a bullet list or numbered list with a single
reference. References in regular text aren't considered as *toctree* .
This feature is enabled by recommonmark's *enable_auto_toc_tree* .
**Example toctree:**
```
* [Chapter 1](chapter1.md)
* [Chapter 2](chapter2.md)
* [Subchapter](sub/index.md)
```
```
1. [Chapter 1](chapter1.md)
2. [Chapter 2](chapter2.md)
```
If you do only reference the document, but do not include it in any toctree,
you'll see the following warning:
**WARNING: document isn't included in any toctree**
## CSV
You can import CSV files and let sphinx automatically convert them to human
readable tables, using the following reStructuredText snipped:
```eval_rst
.. csv-table::
:header: "Key", "Value"
:file: keyvalues.csv
```
Of course this can only be done from a markdown file that is included in the
TOC tree.
[coreboot]: https://coreboot.org
[Documentation]: https://review.coreboot.org/cgit/coreboot.git/tree/Documentation
[sphinx-autobuild]: https://github.com/GaretJax/sphinx-autobuild
[guide]: http://www.sphinx-doc.org/en/stable/install.html
[Sphinx]: http://www.sphinx-doc.org/en/master/
[Markdown Guide]: https://www.markdownguide.org/
[Gerrit Guidelines]: gerrit_guidelines.md
[review.coreboot.org]: https://review.coreboot.org

View File

@@ -1,64 +0,0 @@
Display Panel Specifics
=======================
Timing Parameters
-----------------
From the binary file `edid` in the sys filesystem on Linux, the panel can be
identified. The exact path may differ slightly. Here is an example:
```sh
$ strings /sys/devices/pci0000:00/0000:00:02.0/drm/card0/card0-eDP-1/edid
@0 5
LG Display
LP140WF3-SPD1
```
To figure out the timing parameters, refer to the [Intel Programmer's Reference
Manuals](https://01.org/linuxgraphics/documentation/hardware-specification-prms)
and try to find the datasheet of the panel using the information from `edid`.
In the example above, you would search for `LP140WF3-SPD1`. Find a table listing
the power sequence timing parameters, which are usually named T[N] and also
referenced in Intel's respective registers listing. You need the values for
`PP_ON_DELAYS`, `PP_OFF_DELAYS` and `PP_DIVISOR` for your `devicetree.cb`:
```eval_rst
+-----------------------------+---------------------------------------+-----+
| Intel docs | devicetree.cb | eDP |
+-----------------------------+---------------------------------------+-----+
| Power up delay | `gpu_panel_power_up_delay` | T3 |
+-----------------------------+---------------------------------------+-----+
| Power on to backlight on | `gpu_panel_power_backlight_on_delay` | T7 |
+-----------------------------+---------------------------------------+-----+
| Power Down delay | `gpu_panel_power_down_delay` | T10 |
+-----------------------------+---------------------------------------+-----+
| Backlight off to power down | `gpu_panel_power_backlight_off_delay` | T9 |
+-----------------------------+---------------------------------------+-----+
| Power Cycle Delay | `gpu_panel_power_cycle_delay` | T12 |
+-----------------------------+---------------------------------------+-----+
```
Intel GPU Tools and VBT
-----------------------
The Intel GPU tools are in a package called either `intel-gpu-tools` or
`igt-gpu-tools` in most distributions of Linux-based operating systems.
In the coreboot `util/` directory, you can find `intelvbttool`.
From a running system, you can dump the register values directly:
```sh
$ intel_reg dump --all | grep PCH_PP
PCH_PP_STATUS (0x000c7200): 0x80000008
PCH_PP_CONTROL (0x000c7204): 0x00000007
PCH_PP_ON_DELAYS (0x000c7208): 0x07d00001
PCH_PP_OFF_DELAYS (0x000c720c): 0x01f40001
PCH_PP_DIVISOR (0x000c7210): 0x0004af06
```
You can obtain the timing values from a VBT (Video BIOS Table), which you can
dump from a vendor UEFI image:
```sh
$ intel_vbt_decode data.vbt | grep T3
Power Sequence: T3 2000 T7 10 T9 2000 T10 500 T12 5000
T3 optimization: no
```

View File

@@ -7,14 +7,13 @@ Introduction and Current State in coreboot
*libgfxinit* is a library of full-featured graphics initialization
(aka. modesetting) drivers. It's implemented in SPARK (a subset of
Ada with formal verification features). While not restricted to in
any way, it currently only supports Intel's integrated graphics
controllers (GMA).
any way, it currently only supports Intel's integrated gfx control-
lers (GMA).
Currently, it supports the Intel Core i3/i5/i7 processor line, HDMI
and DP on the Apollo Lake processors and everything but SDVO on G45
and GM45 chipsets. At the time of writing, G45, GM45, everything
from Arrandale to Coffee Lake, and Apollo Lake are verified to work
within *coreboot*.
Currently, it supports the Intel Core i3/i5/i7 processor line and
will support HDMI and DP on the Atom successor Apollo Lake. At the
time of writing, Sandy Bridge, Ivy Bridge, and Haswell are veri-
fied to work within *coreboot*.
GMA: Framebuffer Configuration
------------------------------
@@ -49,16 +48,13 @@ follows:
* `lightup_ok`: returns whether the initialization succeeded `1` or
failed `0`. Currently, only the case that no display
could be found counts as failure. A failure at a
later stage (e.g. failure to train a DP) is not
propagated.
could be found counts as failure. A failure at a la-
ter stage (e.g. failure to train a DP) is not propa-
gated.
GMA: Per Board Configuration
----------------------------
In order to set up the display panel, see the
[display panel-specific documentation](/gfx/display-panel.md).
There are a few Kconfig symbols to consider. To indicate that a
board can initialize graphics through *libgfxinit*:
@@ -80,11 +76,8 @@ know through which interface the EDID can be queried:
select GFX_GMA_ANALOG_I2C_HDMI_D
Beside Kconfig options, *libgfxinit* needs to know which ports are
implemented on a board and should be probed for displays. The mapping
between the physical ports and these entries depends on the hardware
implementation and can be recovered by testing or studying the output
of `intelvbttool` or `intel_vbt_decode`.
Each board has to implement the package `GMA.Mainboard` with a list:
implemented on a board and should be probed for displays. Each
board has to implement the package `GMA.Mainboard` with a list:
ports : HW.GFX.GMA.Display_Probing.Port_List;

View File

@@ -1,6 +0,0 @@
# ifdtool
Contents:
* [Intel IFD Binary Extraction](binary_extraction.md)
* [IFD Layout](layout.md)

View File

@@ -1,66 +0,0 @@
# IFD Layout
A coreboot image for an Intel SoC contains two separate definitions of the
layout of the flash. The Intel Flash Descriptor (IFD) which defines offsets and
sizes of various regions of flash and the [coreboot FMAP](../lib/flashmap.md).
The FMAP should define all of the of the regions defined by the IFD to ensure
that those regions are accounted for by coreboot and will not be accidentally
modified.
## IFD mapping
The names of the IFD regions in the FMAP should follow the convention of
starting with the prefix `SI_` which stands for `silicon initialization` as a
way to categorize anything required by the SoC but not provided by coreboot.
|IFD Region index|IFD Region name|FMAP Name|Notes|
|---|---|---|---|
|0|Flash Descriptor|SI_DESC|Always the top 4KB of flash|
|1|BIOS|SI_BIOS|This is the region that contains coreboot|
|2|Intel ME|SI_ME||
|3|Gigabit Ethernet|SI_GBE||
|4|Platform Data|SI_PDR||
|8|EC Firmware|SI_EC|Most Chrome OS devices do not use this region; EC firmware is stored BIOS region of flash|
## Validation
The ifdtool can be used to manipulate a firmware image with a IFD. This tool
will not take into account the FMAP while modifying the image which can lead to
unexpected and hard to debug issues with the firmware image. For example if the
ME region is defined at 6 MB in the IFD but the FMAP only allocates 4 MB for the
ME, then when the ME is added by the ifdtool 6 MB will be written which could
overwrite 2 MB of the BIOS.
In order to validate that the FMAP and the IFD are compatible the ifdtool
provides --validate (-t) option. `ifdtool -t` will read both the IFD and the
FMAP in the image and for every non empty region in the IFD if that region is
defined in the FMAP but the offset or size is different then the tool will
return an error.
Example:
```console
foo@bar:~$ ifdtool -t bad_image.bin
Region mismatch between bios and SI_BIOS
Descriptor region bios:
offset: 0x00400000
length: 0x01c00000
FMAP area SI_BIOS:
offset: 0x00800000
length: 0x01800000
Region mismatch between me and SI_ME
Descriptor region me:
offset: 0x00103000
length: 0x002f9000
FMAP area SI_ME:
offset: 0x00103000
length: 0x006f9000
Region mismatch between pd and SI_PDR
Descriptor region pd:
offset: 0x003fc000
length: 0x00004000
FMAP area SI_PDR:
offset: 0x007fc000
length: 0x00004000
```

View File

@@ -1,190 +1,21 @@
# Welcome to the coreboot documentation
Welcome to coreboot's documentation!
====================================
This is the developer documentation for [coreboot](https://coreboot.org).
It is built from Markdown files in the
[Documentation](https://review.coreboot.org/cgit/coreboot.git/tree/Documentation)
directory in the source code.
## Purpose of coreboot
coreboot is a project to develop open source boot firmware for various
architectures. Its design philosophy is to do the bare minimum necessary to
ensure that hardware is usable and then pass control to a different program
called the _payload_.
### Separation of concerns
The payload can then provide user interfaces, file system drivers,
various policies etc. to load the OS. Through this separation of concerns
coreboot maximizes reusability of the complicated and fundamental hardware
initialization routines across many different use cases, no matter if
they provide standard interfaces or entirely custom boot flows.
Popular [payloads](payloads.md) in use with coreboot are SeaBIOS,
which provides PCBIOS services, Tianocore, which provides UEFI services,
GRUB2, the bootloader used by many Linux distributions, or depthcharge,
a custom boot loader used on Chromebooks.
### No resident services (if possible)
Ideally coreboot completely hands over control to the payload with no
piece of coreboot remaining resident in the system, or even available
for callback. Given the reality of contemporary computer design,
there's often a small piece that survives for the whole runtime of
the computer. It runs in a highly privileged CPU mode (e.g. SMM on x86)
and provides some limited amount of services to the OS. But here, too,
coreboot aims to keep everything at the minimum possible, both in scope
(e.g. services provided) and code size.
### No specification of its own
coreboot uses a very minimal interface to the payload, and otherwise
doesn't impose any standards on the ecosystem. This is made possible by
separating out concerns (interfaces and resident services are delegated
to the payload), but it's also a value that is deeply ingrained in the
project. We fearlessly rip out parts of the architecture and remodel it
when a better way of doing the same was identified.
### One tree for everything
Another difference to various other firmware projects is that we try
to avoid fragmentation: the traditional development model of firmware
is one of "set and forget" in which some code base is copied, adapted
for the purpose at hands, shipped and only touched again if there's an
important fix to do.
All newer development happens on another copy of some code base without
flowing back to any older copy, and so normally there's a huge amount
of fragmentation.
In coreboot, we try to keep everything in a single source tree, and
lift up older devices when we change something fundamentally. That way,
new and old devices benefit alike from new development in the common parts.
There's a downside to that: Some devices might have no maintainer anymore
who could ensure that coreboot is still functional for them after a big
rework, or maybe a rework even requires knowledge that doesn't exist
anymore within the project (for example because the developer moved on
to do something else).
In this case, we announce the deprecation of the device and defer the big
rework until the deprecation period passed, typically 6-12 months. This
gives interested developers a chance to step in and bring devices up to
latest standards.
While without this deprecation mechanism we could inflate the number
of supported devices (probably 300+), only a tiny fraction of them
would even work, which helps nobody.
## Scope of the coreboot project
coreboot as a project is closer to the Linux kernel than to most
user level programs. One place where this becomes apparent is the
distribution mechanism: The project itself only provides source code
and does not ship ready-to-install coreboot-based firmware binaries.
What the project distributes, even if - strictly speaking - it's not
part of the project, is a collection of vendor binaries (that we call
"blobs") that are redistributable. They cover the parts of hardware init
that we haven't managed to open up, and while some hardware requires them,
there's still hardware that can boot without any such binary components.
The build system can integrate them into the build automatically if
required, but that requires explicit opt-in and downloads a separate
repository to ensure that the distinction remains clear.
There are various [distributions](distributions.md), some shipping
coreboot with their hardware (e.g. Purism or Chromebooks), others
providing after-market images for various devices (e.g. Libreboot,
MrChromebox).
If you want to use coreboot on your system, that's great!
Please note that the infrastructure around coreboot.org is built for
development purposes. We gladly help out users through our communication
channels, but we also expect a "firmware developer mindset": If compiling
your own firmware and, at some point, recovering from a bad flash by
hooking wires onto chips in your computer sounds scary to you, you're
right, as it is.
If that's _way_ beyond your comfort zone, consider looking into the
various distributions, as they typically provide pre-tested binaries
which massively reduces the risk that the binary you write to flash is
one that won't boot the system (with the consequence that to get it to work
again, you'll need to attach various tools to various chips)
## The coreboot community
If you're interested in getting your hands dirty (incl. potentially wiring
up an external flasher to your computer), you've come to the right place!
We have various [forums](community/forums.md) where we discuss and coordinate
our activities, review patches, and help out each other. To
help promote a positive atmosphere, we established a [Code of
Conduct](community/code_of_conduct.md). We invested a lot of time
to balance it out, so please keep it in mind when engaging with the
coreboot community.
Every now and then, coreboot is present in one way or another at
[conferences](community/conferences.md). If you're around, come and
say hello!
## Getting the source code
coreboot is primarily developed in the
[git](https://review.coreboot.org/cgit/coreboot.git) version control
system, using [Gerrit](https://review.coreboot.org) to manage
contributions and code review.
In general we try to keep the `master` branch in the repository functional
for all hardware we support. So far, the only guarantee we can make is
that the master branch will (nearly) always build for all boards in a
standard configuration.
However, we're continually working on improvements to our infrastructure to
get better in that respect, e.g. by setting up boot testing facilities. This
is obviously more complex than regular integration testing, so progress
is slow.
### What our releases mean
We also schedule two source code releases every year, around April and
October. These releases see some very limited testing and mostly serve
as synchronization points for deprecation notices and for other projects
such as external distributions.
This approach and terminology differs somewhat from how other projects handle
releases where releases are well-tested artifacts and the development
repository tends to be unstable. The "rolling release" model of some projects,
for example OpenBSD, is probably the closest cousin of our approach.
Contents:
* [Getting Started](getting_started/index.md)
* [Tutorial](tutorial/index.md)
* [Coding Style](coding_style.md)
* [Project Ideas](contributing/project_ideas.md)
* [Code of Conduct](community/code_of_conduct.md)
* [Community forums](community/forums.md)
* [Project services](community/services.md)
* [coreboot at conferences](community/conferences.md)
* [Payloads](payloads.md)
* [Distributions](distributions.md)
* [Technotes](technotes/index.md)
* [Lesson 2: Submitting a patch to coreboot.org](Lesson2.md)
* [Gerrit Etiquette and Guidelines](gerrit_guidelines.md)
* [coreboot's build system](build_system.md)
* [Kconfig in coreboot](core/Kconfig.md)
* [Use of git submodules in coreboot](submodules.md)
* [Timestamps](timestamp.md)
* [Dealing with Untrusted Input in SMM](technotes/2017-02-dealing-with-untrusted-input-in-smm.md)
* [ABI data consumption](abi-data-consumption.md)
* [GPIO toggling in ACPI AML](acpi/gpio.md)
* [Adding devices to a device tree](acpi/devicetree.md)
* [Native Graphics Initialization with libgfxinit](gfx/libgfxinit.md)
* [Display panel-specific documentation](gfx/display-panel.md)
* [Architecture-specific documentation](arch/index.md)
* [Platform independend drivers documentation](drivers/index.md)
* [Northbridge-specific documentation](northbridge/index.md)
* [System on Chip-specific documentation](soc/index.md)
* [Mainboard-specific documentation](mainboard/index.md)
* [Payload-specific documentation](lib/payloads/index.md)
* [Library-specific documentation](lib/index.md)
* [Security](security/index.md)
* [SuperIO-specific documentation](superio/index.md)
* [Vendorcode-specific documentation](vendorcode/index.md)
* [Utilities](util.md)
* [Release notes for past releases](releases/index.md)
* [Flashing firmware tutorial](flash_tutorial/index.md)
* [Sandy Bridge Raminit](Intel/NativeRaminit/Sandybridge.md)

View File

@@ -1,153 +0,0 @@
# Flashmap and Flashmap Descriptor in coreboot
## Flashmap
[Flashmap](https://code.google.com/p/flashmap) (FMAP) is a binary format to
describe partitions in a flash chip. It was added to coreboot to support the
requirements of Chromium OS firmware but then was also used in other scenarios
where precise placement of data in flash was necessary, or for data that is
written to at runtime, as CBFS is considered too fragile for such situations.
The Flashmap implementation inside coreboot is the de facto standard today.
Flashmap partitions the image into clearly delimited sections and some of those
sections may be CBFSes that can hold arbitrary-length files (at least one, the
default CBFS, called `COREBOOT`). General guidance is that everything with
strict layout requirements (e.g. must be aligned to erase blocks or
something else) should have its own Flashmap section, and everything else should
normally go into CBFS.
The Flashmap itself starts with a header `struct fmap` and followed by a list of
section descriptions in `struct fmap_area`.
### Header
The header `struct fmap` has following fields:
* `signature`: 8 characters as `"__FMAP__"`.
* `ver_major`: one byte for major version (currently only 1).
* `ver_minor`: one byte for minor version (current value is 1).
* `base`: 64 bit integer for the address of the firmware binary.
* `size`: 32 bit integer for the size of firmware binary in bytes.
* `name`: 32 characters for the name of the firmware binary.
* `nareas`: 16 bit integer for the number of area definitions (i.e., how many
sections are in this firmware image) following the header.
### Area Definition
The section is defined by `struct fmap_area` with following fields:
* `offset`: 32 bit integer for where the area starts (relative to `base` in
header).
* `size`: 32 bit integer for the size of area in bytes.
* `name`: 32 characters for a descriptive name of this area. Should be unique to
all sections inside same Flashmap.
* `flags`: 16 bit integer for attributes of this area (see below).
### Area Flags
Currently the defined values for `flags` in `struct fmap_area` are:
* `FMAP_AREA_PRESERVE`: suggesting the section should be preserved when
updating firmware, usually for product data like serial number, MAC address,
or calibration and cache data.
* `FMAP_AREA_STATIC`: Not really used today.
* `FMAP_AREA_COMPRESSED`: Not really used today.
* `FMAP_AREA_RO`: Not really used today.
### FMAP section
The whole Flashmap (`struct fmap` and list of `struct fmap_area`) should be
stored in a standalone section named as `FMAP` (which should be also described
by the Flashmap itself in `struct fmap_area`). There's no restriction for where
it should be located (or how large), but usually we need to do a linear or
binary search on whole firmware binary image to find Flashmap so a properly
aligned address would be better.
### COREBOOT section
coreboot firmware images (`coreboot.rom`) should have at least one Flashmap
section that is reserved for CBFS. Usually it is named as `COREBOOT`.
## Flashmap Descriptor
Since coreboot is starting to use a "partition" of Flashmap to describe the
flash chip layout (both at runtime and when flashing a new image onto a
chip), the project needs a reasonably expressive plain text format for
representing such sections in the source tree.
Flashmap Descriptor (FMD) is a [language and
compiler](https://chromium-review.googlesource.com/#/c/255031) inside coreboot
utility folder that can be used to generate final firmware images (i.e.
`coreboot.rom`) formatted by Flashmap.
The FMD implementation is in coreboot `utils/cbfstool` folder. Here's an
informal language description:
```
# <line comment>
<image name>[@<memory-mapped address>] <image size> {
<section name>[(flags)][@<offset from start of image>] [<section size>] [{
<subsection name>[@<offset from start of parent section>] [<subsection size>] [{
# Sections can be nested as deeply as desired
<subsubsection name>[(flags)][@...] [...] [{...}]
}]
[<subsection name>[(flags)][@...] [...] [{...}]]
# There can be many subsections at each level of nesting: they will be inserted
# sequentially, and although gaps are allowed, any provided offsets are always
# relative to the closest parent node's and must be strictly increasing with neither
# overlapping nor degenerate-size sections.
}]
}
```
Note that the above example contains a few symbols that are actually meta
syntax, and therefore have neither meaning nor place in a real file. The `<.*>`s
indicate placeholders for parameters:
* The names are strings, which are provided as single-word (no white space)
groups of syntactically unimportant symbols (i.e. every thing except `@`, `{`,
and `}`): they are not surrounded by quotes or any other form of delimiter.
* The other fields are non-negative integers, which may be given as decimal or
hexadecimal; in either case, a `K`, `M`, or `G` may be appended (without
intermediate white space) as a multiplier.
* Comments consist of anything one manages to enter, provided it doesn't start a
new line.
The `[.*]`s indicate that a portion of the file could be omitted altogether:
* Just because something is noted as optional doesn't mean it is in every case:
the answer might actually depend on which other information is---or
isn't---provided.
* The "flag" specifies the attribute or type for given section. The most
important supported flag is "CBFS", which indicates the section will contain
a CBFS structure.
* In particular, it is only legal to place a (CBFS) flag on a leaf section; that
is, choosing to add child sections excludes the possibility of putting a CBFS
in their parent. Such flags are only used to decide where CBFS empty file
headers should be created, and do not result in the storage of any additional
metadata in the resulting FMAP section.
Additionally, it's important to note these properties of the overall file and
its values:
* Other than within would-be strings and numbers, white space is ignored. It
goes without saying that such power comes with responsibility, which is why
this sentence is here.
* Although the `section name` must be globally unique, one of them may (but is
not required to) match the image name.
* It is a syntax error to supply a number (besides 0) that begins with the
character `0`, as there is no intention of adding octals to the mix.
* The image's memory address should be present on (and only on) layouts for
memory-mapped chips.
* Although it may be evident from above, all `section` offsets are relative only
to the immediate parent. There is no way to include an absolute offset (i.e.
from the beginning of flash), which means that it is "safe" to reorder the
sections within a particular level of nesting, as long as the change doesn't
cause their positions and sizes to necessitate overlap or zero sizes.
* A `section` with omitted offset is assumed to start at as low a position as
possible (with no consideration of alignment) and one with omitted size is
assumed to fill the remaining space until the next sibling or before the end
of its parent.
* It's fine to omit any `section`'s offset, size, or both, provided its position
and size are still unambiguous in the context of its *sibling* sections and
its parent's *size*. In particular, knowledge of one .*section 's children or
the `section`s' common parent's siblings will not be used for this purpose.
* Although `section`s are not required to have children, the flash chip as a
whole must have at least one.
* Though the braces after `section`s may be omitted for those that have no
children, if they are present, they must contain at least one child.
To see the formal description of the language, please refer to the Lex and Yacc
files: `fmd_scanner.l` and `fmd_scanner.y`.

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# Library-specific documentation
This section contains documentation about coreboot internal technical
information and libraries.
## Structure and layout
- [Flashmap and Flashmap Descriptor](flashmap.md)
- [ABI data consumption](abi-data-consumption.md)
- [Timestamps](timestamp.md)

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# Flattened uImage Tree documentation
[uImage.FIT] is the new format used for uImage payloads developed by
[U-boot].
## Supported architectures
* aarch64
* riscv
## Supported FIT sections
The FIT can contain multiple sections, each holding a unique
kernel, initrd or config. Out of the sections one kernel and
one initrd is chosen, depending on the matching config.
The config is selected depending on the compat string.
The section must be named in order to be found by the FIT parser:
* kernel
* fdt
* ramdisk
## Architecture specifics
The FIT parser needs architecure support.
### aarch64
The source code can be found in `src/arch/arm64/fit_payload.c`.
On aarch64 the kernel (a section named 'kernel') must be in **Image**
format and it needs a devicetree (a section named 'fdt') to boot.
The kernel will be placed close to "*DRAMSTART*".
### RISC-V
The source code can be found in `src/arch/riscv/fit_payload.c`.
On RISC-V the kernel (a section named 'kernel') must be in **Image**
format and it needs a devicetree (a section named 'fdt') to boot.
The kernel will be placed close to "*DRAMSTART*".
### Other
Other architectures aren't supported.
## Supported compression
The FIT image has to be included uncompressed into the CBFS. The sections
inside the FIT image can use different compression schemes.
Supported compression algorithms:
* LZMA
* LZ4
* none
## Compat string
The config entries contain a compatible string, that is used to find a
matching config.
The following mainboard specific funtions provide the BOARDID and SKUID:
```c
uint32_t board_id(void);
```
```c
uint32_t sku_id(void);
```
By default the following compat strings are added:
* *CONFIG_MAINBOARD_VENDOR*,*CONFIG_MAINBOARD_PART_NUMBER*
* *CONFIG_MAINBOARD_VENDOR*,*CONFIG_MAINBOARD_PART_NUMBER*-rev*BOARDID*
* *CONFIG_MAINBOARD_VENDOR*,*CONFIG_MAINBOARD_PART_NUMBER*-rev*BOARDID*-sku*SKUID*
Example:
```
cavium,cn8100_sff_evb
```
If *board_id()* or *sku_id()* return invalid, the single comapt string isn't added.
You can add custom compat strings by calling:
```c
fit_add_compat_string(const char *str);
```
If no matching compat string is found, the default config is chosen.
## Building FIT image
The FIT image has to be built by calling `mkimage`. You can use
the following example configuration:
```
/*
* Simple U-Boot uImage source file containing a single kernel and FDT blob
*/
/dts-v1/;
/ {
description = "Simple image with single Linux kernel and FDT blob";
#address-cells = <1>;
images {
kernel {
description = "Vanilla Linux kernel";
data = /incbin/("Image.lzma");
type = "kernel";
arch = "arm64";
os = "linux";
compression = "lzma";
load = <0x80000>;
entry = <0x80000>;
hash-1 {
algo = "crc32";
};
};
fdt-1 {
description = "Flattened Device Tree blob";
data = /incbin/("target.dtb");
type = "flat_dt";
arch = "arm64";
compression = "none";
hash-1 {
algo = "crc32";
};
};
ramdisk-1 {
description = "Compressed Initramfs";
data = /incbin/("initramfs.cpio.xz");
type = "ramdisk";
arch = "arm64";
os = "linux";
compression = "none";
load = <00000000>;
entry = <00000000>;
hash-1 {
algo = "sha1";
};
};
};
configurations {
default = "conf-1";
conf-1 {
description = "Boot Linux kernel with FDT blob";
kernel = "kernel";
fdt = "fdt-1";
ramdisk = "ramdisk-1";
};
};
};
```
Save it as ITS file `config.its` along with the other files defined here:
* target.dtb
* initramfs.cpio.xz
* Image.lzma
Generate the `uImage` that will be included into the CBFS by calling
```bash
mkimage -f config.its uImage
```
The generated file includes a compressed initrd **initramfs.cpio.xz**, which
will be decompressed by the Linux kernel, a compressed kernel **Image.lzma**,
which will be decompressed by the FIT loader and an uncompressed devicetree blob.
[uImage.FIT]: https://raw.githubusercontent.com/u-boot/u-boot/master/doc/uImage.FIT/howto.txt
[U-Boot]: https://www.denx.de/wiki/U-Boot

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# Payload-specific documentation
This section contains documentation about coreboot on specific payloads.
Payloads are run after coreboot has initialized the hardware.
coreboot supports multiple payloads, depending on the architecture of the
selected mainboard.
## FIT
- [uImage.FIT support](fit.md)

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# Padmelon board
## Specs (with Merlin Falcon SOC)
* Two 260-pin DDR4 SO-DIMM slots, 1.2V DDR4-1333/1600/1866/2133 SO-DIMMs
Supports 4GB, 8GB and 16GB DDR4 unbuffered ECC (Merlin Falcon)SO-DIMMs
* Can use Prairie Falcon, Brown Falcon, Merlin Falcon, though coreboot
code is specific for Merlin Falcon SOC. Some specs will change if not
using Merlin Falcon.
* One half mini PCI-Express slot on back side of mainboard
* One PCI Express® 3.0 x8 slot
* Two SATA3 ports with 6Gb/s data transfer rate
* Two USB 2.0 ports at rear panel
* Two USB 3.0 ports at rear panel
* Dual Gigabit Ethernet from Realtek RTL8111F Gigabit controller
* 6-channel High-Definition audio from Realtek ALC662 codec
* One soldered down SPI flash with dediprog header
## Mainboard
![mainboard][padmelon]
Three items are marked in this picture
1. dediprog header
2. memory dimms, address 0xA0 and 0xA4
3. SATA cables connected to motherboard
## Back panel
![back panel][padmelon_io]
* The lower serial port is UART A (debug serial)
## Flashing coreboot
```eval_rst
+---------------------+--------------------+
| Type | Value |
+=====================+====================+
| Socketed flash | no |
+---------------------+--------------------+
| Model | Macronix MX256435E |
+---------------------+--------------------+
| Size | 8 MiB |
+---------------------+--------------------+
| Flash programing | dediprog header |
+---------------------+--------------------+
| Package | SOIC-8 |
+---------------------+--------------------+
| Write protection | No |
+---------------------+--------------------+
```
## Technology
```eval_rst
+---------------+------------------------------+
| Fan control | Using fintek F81803A |
+---------------+------------------------------+
| CPU | Merlin Falcon (see reference)|
+---------------+------------------------------+
```
## Description of pictures within this document
```eval_rst
+----------------------------+----------------------------------------+
|padmelon.jpg | Motherboard with components identified |
+----------------------------+----------------------------------------+
|padmelon_io.jpg | Back panel picture |
+----------------------------+----------------------------------------+
```
## Reference
[Merlin Falcon BKDG][merlinfalcon]
[merlinfalcon]: ../../../soc/amd/family15h.md
[padmelon]: padmelon.jpg
[padmelon_io]: padmelon_io.jpg

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# ASRock H110M-DVS
This page describes how to run coreboot on the [ASRock H110M-DVS].
## Required proprietary blobs
Mainboard is based on Intel Skylake/Kaby Lake processor and H110 Chipset.
Intel company provides [Firmware Support Package (2.0)](../../soc/intel/fsp/index.md)
(intel FSP 2.0) to initialize this generation silicon. Please see this
[document](../../soc/intel/code_development_model/code_development_model.md).
FSP Information:
```eval_rst
+-----------------------------+-------------------+-------------------+
| FSP Project Name | Directory | Specification |
+-----------------------------+-------------------+-------------------+
| 7th Generation Intel® Core™ | KabylakeFspBinPkg | 2.0 |
| processors and chipsets | | |
| (formerly Kaby Lake) | | |
+-----------------------------+-------------------+-------------------+
```
## Building coreboot
The following steps set the default parameters for this board to build a
fully working image:
```bash
make distclean
touch .config
./util/scripts/config --enable VENDOR_ASROCK
./util/scripts/config --enable BOARD_ASROCK_H110M_DVS
./util/scripts/config --enable CONFIG_ADD_FSP_BINARIES
./util/scripts/config --enable CONFIG_FSP_USE_REPO
./util/scripts/config --set-str REALTEK_8168_MACADDRESS "xx:xx:xx:xx:xx:xx"
make olddefconfig
```
However, it is strongly advised to use `make menuconfig` afterwards
(or instead), so that you can see all of the settings.
Use the following command to disable the serial console if debugging
output is not required:
```bash
./util/scripts/config --disable CONSOLE_SERIAL
```
However, a more flexible method is to change the console log level from
within an OS using `util/nvramtool`, or with the `nvramcui` payload.
Now, run `make` to build the coreboot image.
## Flashing coreboot
### Internal programming
The main SPI flash can be accessed using [flashrom]. By default, only
the BIOS region of the flash is writable. If you wish to change any
other region, such as the Management Engine or firmware descriptor, then
an external programmer is required (unless you find a clever way around
the flash protection). More information about this [here](../../flash_tutorial/index.md).
### External programming
The flash chip is a 8 MiB socketed DIP-8 chip. Specifically, it's a
Macronix MX25L6473E, whose datasheet can be found [here][MX25L6473E].
The chip is located to the bottom right-hand side of the board. For
a precise location, refer to section 1.3 (Motherboard Layout) of the
[H110M-DVS manual], where the chip is labelled "64Mb BIOS". Take note of
the chip's orientation, remove it from its socket, and flash it with
an external programmer. For reference, the notch in the chip should be
facing towards the bottom of the board.
## Known issues
- The VGA port doesn't work. Discrete graphic card is used as primary
device for display output (if CONFIG_ONBOARD_VGA_IS_PRIMARY is not
set). Dynamic switching between iGPU and PEG is not yet supported.
- SuperIO GPIO pin is used to reset Realtek chip. However, since the
Logical Device 7 (GPIO6, GPIO7, GPIO8) is not initialized, the network
chip is in a reset state all the time.
## Untested
- parallel port
- PS/2 keyboard
- PS/2 mouse
- EHCI debug
- TPM
- infrared module
- chassis intrusion header
- chassis speaker header
## Working
- integrated graphics init with libgfxinit (see [Known issues](#known-issues))
- PCIe x1
- PEG x16 Gen3
- SATA
- USB
- serial port
- onboard audio
- using `me_cleaner`
- using `flashrom`
## TODO
- NCT6791D GPIOs
- onboard network (see [Known issues](#known-issues))
- S3 suspend/resume
- Wake-on-LAN
- hardware monitor
## Technology
```eval_rst
+------------------+--------------------------------------------------+
| CPU | Intel Skylake/Kaby Lake (LGA1151) |
+------------------+--------------------------------------------------+
| PCH | Intel Sunrise Point H110 |
+------------------+--------------------------------------------------+
| Super I/O | Nuvoton NCT6791D |
+------------------+--------------------------------------------------+
| EC | None |
+------------------+--------------------------------------------------+
| Coprocessor | Intel Management Engine |
+------------------+--------------------------------------------------+
```
[ASRock H110M-DVS]: https://www.asrock.com/mb/Intel/H110M-DVS%20R2.0/
[MX25L6473E]: http://www.macronix.com/Lists/Datasheet/Attachments/7380/MX25L6473E,%203V,%2064Mb,%20v1.4.pdf
[flashrom]: https://flashrom.org/Flashrom
[H110M-DVS manual]: http://asrock.pc.cdn.bitgravity.com/Manual/H110M-DVS%20R2.0.pdf

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# ASRock H81M-HDS
This page describes how to run coreboot on the [ASRock H81M-HDS].
## Required proprietary blobs
```eval_rst
Please see :doc:`../../northbridge/intel/haswell/mrc.bin`.
```
## Building coreboot
A fully working image should be possible just by setting your MAC
address and obtaining the Haswell mrc. You can set the basic config
with the following commands. However, it is strongly advised to use
`make menuconfig` afterwards (or instead), so that you can see all of
the settings.
```bash
make distclean # Note: this will remove your current config, if it exists.
touch .config
./util/scripts/config --enable VENDOR_ASROCK
./util/scripts/config --enable BOARD_ASROCK_H81M_HDS
./util/scripts/config --enable HAVE_MRC
./util/scripts/config --set-str REALTEK_8168_MACADDRESS "xx:xx:xx:xx:xx:xx" # Fill this in!
make olddefconfig
```
If you don't plan on using coreboot's serial console to collect logs,
you might want to disable it at this point (`./util/scripts/config
--disable CONSOLE_SERIAL`). It should reduce the boot time by several
seconds. However, a more flexible method is to change the console log
level from within an OS using `util/nvramtool`, or with the `nvramcui`
payload.
Now, run `make` to build the coreboot image.
## Flashing coreboot
### Internal programming
The main SPI flash can be accessed using [flashrom]. By default, only
the BIOS region of the flash is writable. If you wish to change any
other region, such as the Management Engine or firmware descriptor, then
an external programmer is required (unless you find a clever way around
the flash protection).
The following command may be used to flash coreboot:
```bash
sudo flashrom -p internal --ifd -i bios --noverify-all -w coreboot.rom
```
The use of `--noverify-all` is required since the Management Engine
region is not readable even by the host.
### External programming
The flash chip is a 4 MiB socketed DIP-8 chip. Specifically, it's a
Winbond W25Q32FV, whose datasheet can be found [here][W25Q32FV].
The chip is located to the bottom right-hand side of the board. For
a precise location, refer to section 1.4 (Motherboard Layout) of the
[board manual], where the chip is labelled "32Mb BIOS". Take note of
the chip's orientation, remove it from its socket, and flash it with
an external programmer. For reference, the notch in the chip should be
facing towards the bottom of the board.
## Known issues
- The VGA port doesn't work until the OS reinitialises the display.
- There is no automatic, OS-independent fan control. This is because
the Super I/O hardware monitor can only obtain valid CPU temperature
readings from the PECI agent, but the required driver doesn't exist
in coreboot. The `coretemp` driver can still be used for accurate CPU
temperature readings from an OS.
```eval_rst
Please also see :doc:`../../northbridge/intel/haswell/known-issues`.
```
## Untested
- parallel port
- PS/2 keyboard
- EHCI debug
- TPM
- infrared module
- chassis intrusion header
- chassis speaker header
## Working
- USB
- S3 suspend/resume
- Gigabit Ethernet
- integrated graphics
- PCIe
- SATA
- PS/2 mouse
- serial port
- hardware monitor (see [Known issues](#known-issues))
- onboard audio
- front panel audio
- initialisation with Haswell mrc version 1.6.1 build 2
- graphics init with libgfxinit (see [Known issues](#known-issues))
- flashrom under the vendor firmware
- flashrom under coreboot
- Wake-on-LAN
- Using `me_cleaner`
## Technology
```eval_rst
+------------------+--------------------------------------------------+
| Northbridge | :doc:`../../northbridge/intel/haswell/index` |
+------------------+--------------------------------------------------+
| Southbridge | Intel Lynx Point (H81) |
+------------------+--------------------------------------------------+
| CPU | Intel Haswell (LGA1150) |
+------------------+--------------------------------------------------+
| Super I/O | Nuvoton NCT6776 |
+------------------+--------------------------------------------------+
| EC | None |
+------------------+--------------------------------------------------+
| Coprocessor | Intel Management Engine |
+------------------+--------------------------------------------------+
```
[ASRock H81M-HDS]: https://www.asrock.com/mb/Intel/H81M-HDS/
[W25Q32FV]: https://www.winbond.com/resource-files/w25q32fv%20revi%2010202015.pdf
[flashrom]: https://flashrom.org/Flashrom
[Board manual]: http://asrock.pc.cdn.bitgravity.com/Manual/H81M-HDS.pdf

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# ASUS F2A85-M
This page describes how to run coreboot on the [ASUS F2A85-M].
## Variants
- ASUS F2A85-M - Working
- ASUS F2A85-M LE - Working
- ASUS F2A85-M PRO - Working
- ASUS F2A85-M2 - Working
- ASUS F2A85-M/CSM - Unsure if WIP.
## Technology
Both "Trinity" and "Richland" desktop processing units are working,
the CPU architecture in these CPUs/APUs is [Piledriver],
and their GPU is [TeraScale 3] (VLIW4-based).
```eval_rst
+------------------+--------------------------------------------------+
| F2A85-M | |
+------------------+--------------------------------------------------+
| DDR voltage IC | Nuvoton NCT3933U (AUX SMBUS 0x15) |
+------------------+--------------------------------------------------+
| Network | Realtek RTL8111F |
+------------------+--------------------------------------------------+
| Northbridge | Integrated into CPU with IMC and GPU (APUs only) |
+------------------+--------------------------------------------------+
| Southbridge | Hudson-D4 |
+------------------+--------------------------------------------------+
| Sound IC | Realtek ALC887 |
+------------------+--------------------------------------------------+
| Super I/O | ITE 8603E |
+------------------+--------------------------------------------------+
| VRM controller | DIGI VRM ASP1106 (Rebranded RT8894A - SMBUS 0x20)|
+------------------+--------------------------------------------------+
```
```eval_rst
+------------------+--------------------------------------------------+
| F2A85-M LE | |
+------------------+--------------------------------------------------+
| DDR voltage IC | Nuvoton NCT3933U (AUX SMBUS 0x15 - unconfirmed) |
+------------------+--------------------------------------------------+
| Network | Realtek RTL8111F |
+------------------+--------------------------------------------------+
| Northbridge | Integrated into CPU with IMC and GPU(APUs only) |
+------------------+--------------------------------------------------+
| Southbridge | Hudson-D4 |
+------------------+--------------------------------------------------+
| Sound IC | Realtek ALC887 |
+------------------+--------------------------------------------------+
| Super I/O | ITE 8623E |
+------------------+--------------------------------------------------+
| VRM controller | DIGI VRM ASP1106 (Rebranded RT8894A - SMBUS 0x20)|
+------------------+--------------------------------------------------+
```
```eval_rst
+------------------+--------------------------------------------------+
| F2A85-M PRO | |
+------------------+--------------------------------------------------+
| DDR voltage IC | Nuvoton NCT3933U (?) |
+------------------+--------------------------------------------------+
| Network | Realtek RTL8111F - Not working |
+------------------+--------------------------------------------------+
| Northbridge | Integrated into CPU with IMC and GPU(APUs only) |
+------------------+--------------------------------------------------+
| Southbridge | Hudson-D4 |
+------------------+--------------------------------------------------+
| Sound IC | Realtek ALC887 |
+------------------+--------------------------------------------------+
| Super I/O | Nuvoton NCT6779D |
+------------------+--------------------------------------------------+
| VRM controller | DIGI VRM ASP1107 |
+------------------+--------------------------------------------------+
```
## Flashing coreboot
```eval_rst
+---------------------+------------+
| Type | Value |
+=====================+============+
| Socketed flash | yes |
+---------------------+------------+
| Model | W25Q64F |
+---------------------+------------+
| Size | 8 MiB |
+---------------------+------------+
| Package | DIP-8 |
+---------------------+------------+
| Write protection | no |
+---------------------+------------+
| Dual BIOS feature | no |
+---------------------+------------+
| Internal flashing | yes |
+---------------------+------------+
```
### Internal programming
The main SPI flash can be accessed using [flashrom].
UEFI builds that allow flash chip access:
> v5016 is untested, but expected to work as well
> v5018
> v5103
> v5104
> v5107
> v5202
> v6002
> v6004
> v6102
> v6402
> v6404 (requires downgrading to v6402 to flash coreboot)
> v6501 (requires downgrading to v6402 to flash coreboot)
> v6502 (requires downgrading to v6402 to flash coreboot)
Build v6502, v6501 and v6404 do not allow access to the flash chip.
Fortunately it is possible to downgrade build v6502, v6501, v6404 to v6402, with EZFlash.
Downgrading is done by downloading build v6402 from ASUS' F2A85-M download page
and copying it to (the root directory of) a FAT32 formatted USB flash drive.
Enter the EFI setup, switch to advanced mode if necessary,
open the 'Tool' tab and select "ASUS EZ Flash 2 Utility".
## Integrated graphics
### Option 1: Retrieve the VGA optionrom from the vendor EFI binary by running:
# dd if=/dev/mem of=vgabios.bin bs=1k count=64 skip=768
### Option 2: Extract from the vendor binary
Download the BIOS from the Support section at [ASUS F2A85-M].
Using MMTool Aptio (versions 4.5.0 and 5.0.0):
- Load image, click on 'Extract tab'
- Select the 'export path' and 'link present' options
- Choose option ROM '1002,9900' and click on 'Extract'
This version is usable for all the GPUs.
> 1002,9901 Trinity (Radeon HD 7660D)
> 1002,9904 Trinity (Radeon HD 7560D)
> 1002,990c Richland (Radeon HD 8670D)
> 1002,990e Richland (Radeon HD 8570D)
> 1002,9991 Trinity (Radeon HD 7540D)
> 1002,9993 Trinity (Radeon HD 7480D)
> 1002,9996 Richland (Radeon HD 8470D)
> 1002,9998 Richland (Radeon HD 8370D)
> 1002,999d Richland (Radeon HD 8550D)
## Known issues
- buggy USB 3.0 controller (works fine as 2.0 port)
- reboot, poweroff, S3 suspend/resume (broken since 4.8.1)
## Known issues (untested because of non-working ACPI sleep)
- blink in suspend mode (GP43, program LDN7 F8=23 and blink with F9=2 for 1s blinks)
- fix immediate resume after suspend (perhaps PCIe STS needs to be cleared)
- fix resume with USB3.0 used (perhaps there is a bug in resume.c)
## Untested
- audio over HDMI
- IOMMU
- PS/2 mouse
## TODOs
- manage to use one ATOMBIOS for all the integrated GPUs
## Working
- ACPI
- CPU frequency scaling
- flashrom under coreboot
- Gigabit Ethernet
- Hardware monitor
- Integrated graphics
- KVM
- Onboard audio
- PCIe
- PS/2 keyboard
- SATA
- Serial port
- SuperIO based fan control
- USB (XHCI is buggy)
## Extra resources
- [Board manual]
- Flash chip datasheet [W25Q64FV]
[ASUS F2A85-M]: https://www.asus.com/Motherboards/F2A85M/
[Board manual]: https://dlcdnets.asus.com/pub/ASUS/mb/SocketFM2/F2A85-M/E8005_F2A85-M.pdf
[flashrom]: https://flashrom.org/Flashrom
[Piledriver]: https://en.wikipedia.org/wiki/Piledriver_%28microarchitecture%29#APU_lines
[TeraScale 3]: https://en.wikipedia.org/wiki/TeraScale_%28microarchitecture%29#TeraScale_3
[W25Q64FV]: https://www.winbond.com/resource-files/w25q64fv%20revs%2007182017.pdf

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# ASUS P8H61-M LX
This page describes how to run coreboot on the [ASUS P8H61-M LX].
## Flashing coreboot
```eval_rst
+---------------------+------------+
| Type | Value |
+=====================+============+
| Socketed flash | yes |
+---------------------+------------+
| Model | W25Q32BV |
+---------------------+------------+
| Size | 4 MiB |
+---------------------+------------+
| Package | DIP-8 |
+---------------------+------------+
| Write protection | no |
+---------------------+------------+
| Dual BIOS feature | no |
+---------------------+------------+
| Internal flashing | yes |
+---------------------+------------+
```
### Internal programming
The main SPI flash can be accessed using [flashrom]. By default, only
the BIOS region of the flash is writable. If you wish to change any
other region (Management Engine or flash descriptor), then an external
programmer is required.
The following command may be used to flash coreboot:
```
$ sudo flashrom --noverify-all --ifd -i bios -p internal -w coreboot.rom
```
The use of `--noverify-all` is required since the Management Engine
region is not readable even by the host.
## Known issues
- S3 suspend/resume does not work. This is the case for both coreboot
and the vendor firmware, tested with Linux 4.9, Linux 4.17, and
OpenBSD 6.3. Interestingly, it is possible to resume from S3 with
Linux, but _only_ if the resume is started immediately after the
suspend.
- There is no automatic, OS-independent fan control. This is because
the Super I/O hardware monitor can only obtain valid CPU temperature
readings from the PECI agent, whose complete initialisation is not
publicly documented. The `coretemp` driver can still be used for
accurate CPU temperature readings.
## Untested
- PCIe graphics
- parallel port
- PS/2 keyboard
- EHCI debug
- S/PDIF audio
## Working
- USB
- Gigabit Ethernet
- integrated graphics
- PCIe
- SATA
- PS/2 mouse
- serial port
- hardware monitor (see [Known issues](#known-issues) for caveats)
- onboard audio
- front panel audio
- native raminit (2 x 2GB, DDR3-1333)
- native graphics init (libgfxinit)
- flashrom under the vendor firmware
- flashrom under coreboot
- Wake-on-LAN
- Using `me_cleaner` (add `-S --whitelist EFFS,FCRS` if not using
`me_cleaner` as part of the coreboot build process).
## Technology
```eval_rst
+------------------+--------------------------------------------------+
| Northbridge | :doc:`../../northbridge/intel/sandybridge/index` |
+------------------+--------------------------------------------------+
| Southbridge | bd82x6x |
+------------------+--------------------------------------------------+
| CPU | model_206ax |
+------------------+--------------------------------------------------+
| Super I/O | Nuvoton NCT6776 |
+------------------+--------------------------------------------------+
| EC | None |
+------------------+--------------------------------------------------+
| Coprocessor | Intel Management Engine |
+------------------+--------------------------------------------------+
```
## Extra resources
- [Board manual]
- [Flash chip datasheet][W25Q32BV]
[ASUS P8H61-M LX]: https://www.asus.com/Motherboards/P8H61M_LX/
[W25Q32BV]: https://www.winbond.com/resource-files/w25q32bv_revi_100413_wo_automotive.pdf
[flashrom]: https://flashrom.org/Flashrom
[Board manual]: http://dlcdnet.asus.com/pub/ASUS/mb/LGA1155/P8H61_M_LX/E6803_P8H61-M_LX.zip

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# ASUS P8H61-M Pro
This page describes how to run coreboot on the [ASUS P8H61-M Pro].
## Flashing coreboot
```eval_rst
+---------------------+------------+
| Type | Value |
+=====================+============+
| Socketed flash | yes |
+---------------------+------------+
| Model | W25Q32BV |
+---------------------+------------+
| Size | 4 MiB |
+---------------------+------------+
| Package | DIP-8 |
+---------------------+------------+
| Write protection | no |
+---------------------+------------+
| Dual BIOS feature | no |
+---------------------+------------+
| Internal flashing | yes |
+---------------------+------------+
```
The flash IC is located right next to one of the SATA ports:
![](p8h61-m_pro.jpg)
### Internal programming
The main SPI flash can be accessed using [flashrom]. By default, only
the BIOS region of the flash is writable. If you wish to change any
other region (Management Engine or flash descriptor), then an external
programmer is required.
The following command may be used to flash coreboot:
```
$ sudo flashrom --noverify-all --ifd -i bios -p internal -w coreboot.rom
```
The use of `--noverify-all` is required since the Management Engine
region is not readable even by the host.
## Known issues
- There is no automatic, OS-independent fan control. This is because
the Super I/O hardware monitor can only obtain valid CPU temperature
readings from the PECI agent, whose complete initialisation is not
publicly documented. The `coretemp` driver can still be used for
accurate CPU temperature readings.
- me_cleaner breaks LPC bus and attached components!
- PS/2 mouse doesn't work
## Untested
- parallel port
- EHCI debug
- S/PDIF audio
## Working
- PS/2 keyboard
- PCIe graphics
- USB
- Gigabit Ethernet
- Integrated graphics
- SATA
- Serial port
- hardware monitor (see [Known issues](#known-issues) for caveats)
- front panel audio
- Native raminit (2 x 2GB, DDR3-1333)
- Native graphics init (libgfxinit)
- Wake-on-LAN
- TPM on TPM-header
## Technology
```eval_rst
+------------------+--------------------------------------------------+
| Northbridge | :doc:`../../northbridge/intel/sandybridge/index` |
+------------------+--------------------------------------------------+
| Southbridge | bd82x6x |
+------------------+--------------------------------------------------+
| CPU | model_206ax |
+------------------+--------------------------------------------------+
| Super I/O | Nuvoton NCT6776 |
+------------------+--------------------------------------------------+
| EC | None |
+------------------+--------------------------------------------------+
| Coprocessor | Intel Management Engine |
+------------------+--------------------------------------------------+
```
## Extra resources
- [Flash chip datasheet][W25Q32BV]
[ASUS P8H61-M Pro]: https://www.asus.com/Motherboards/P8H61M_Pro/
[W25Q32BV]: https://www.winbond.com/resource-files/w25q32bv_revi_100413_wo_automotive.pdf
[flashrom]: https://flashrom.org/Flashrom

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# ASUS P8Z77-M Pro
This page describes how to run coreboot on the [ASUS P8Z77-M Pro]
## Flashing coreboot
```eval_rst
+---------------------+----------------+
| Type | Value |
+=====================+================+
| Socketed flash | yes |
+---------------------+----------------+
| Model | W25Q64FVA1Q |
+---------------------+----------------+
| Size | 8 MiB |
+---------------------+----------------+
| Package | DIP-8 |
+---------------------+----------------+
| Write protection | yes |
+---------------------+----------------+
| Dual BIOS feature | no |
+---------------------+----------------+
| Internal flashing | yes |
+---------------------+----------------+
```
The flash IC is located right next to one of the SATA ports:
![](p8z77-m_pro.jpg)
### Internal programming
The main SPI flash cannot be written because Asus disables BIOSWE and
enables BLE/SMM_BWP flags in BIOS_CNTL for their latest bioses.
An external programmer is required. You must flash standalone,
flashing in-circuit doesn't work. The flash chip is socketed, so it's
easy to remove and reflash.
## Working
- PS/2 keyboard with SeaBIOS & Tianocore (in Mint 18.3/19.1)
- Rear/front headphones connector audio & mic
- S3 Suspend to RAM (tested with OS installed in a HDD/SSD and also with a
Mint 18.3/19.1 LiveUSB pendrive connected to USB3/USB2), but please
see [Known issues]
- USB2 on rear (tested mouse/keyboard plugged there. Also, booting with
a Mint 18./19.1 LiveUSB works ok)
- USB3 (Z77's and Asmedia's works, but please see [Known issues])
- Gigabit Ethernet (RTL8111F)
- SATA3, SATA2 and eSATA (tested on all ports, hot-swap and TCG OPAL working)
(Blue SATA2) (Blue SATA2) (White SATA3) (Red eSATA SATA3 rear)
port 3 port 5 port 1 port 8
port 4 port 6 port 2 port 7
- NVME SSD boot on PCIe-x16/x8/4x slot using Tianocore
(tested with M.2-to-PCIe adapter and a M.2 Samsung EVO 970 SSD)
- CPU Temp sensors (tested PSensor on linux + HWINFO64 on Win10)
- TPM on TPM-header (tested tpm-tools with Asus TPM 1.2 Infineon SLB9635TT12)
- Native raminit and also MRC.bin(systemagent-r6.bin) memory initialization
(please see [Native raminit compatibility] and [MRC memory compatibility])
- Integrated graphics with both libgfxinit and the Intel Video BIOS OpROM
(VGA/DVI-D/HDMI tested and working)
- 1x PCIe GPU in PCIe-16x/8x/4x slots (tested using Zotac GeForce GTX
750Ti and FirePro W5100 under Mint 18.3/19.1)
## Known issues
- The rear's USB3s on bottom (closest to the PCB) have problems booting or
being used before the OS loads. For better compatibility, please use
the Z77's ones above the Ethernet connector or the Asmedia's top one
- After S3 suspend, some USB3 connectors on rear seem not to work
- At the moment, the power led does not blink when entering S3 state
- Currently, we have not setup the SuperIO's Hardware Monitor (HWM),
so only the CPU sensors are reported
- If you use the MRC.bin, the NVRAM variable gfx_uma_size may be ignored
as IGP's UMA could be reconfigured by the blob
- Using TianoCore + a PCIe GPU under Windows crashes with an
ACPI_BIOS_ERROR fatal code, not sure why. Using just the IGP
works perfectly
- Under Windows 10, if you experiment problems with PS/2 devices, change
HKLM\SYSTEM\CurrentControlSet\Services\i8042prt->Start from '3' to '1'
## Untested
- EHCI debugging
- S/PDIF audio
- Wake-on-LAN
- Serial port
## Not working
- PS/2 keyboard in Win10 using Tianocore (please see [Known issues])
- PS/2 mouse using Tianocore
- PCIe graphics card on Windows and Tianocore (throws critical ACPI_BIOS_ERROR)
## Native raminit compatibility
- GSkill F3-2133C10D-16GAB(XMP,1.60v) 2x8GB kit works at 1333Mhz instead
of XMP 2133Mhz
- Team Xtreem TXD38G2133HC9NDC01(XMP,1.50v) 2x4GB kit works at 1600Mhz
instead of XMP 2133Mhz
- Kingston KVR1066D3N7K2/4G(JEDEC,1.50v) 2x4GB kit works at 1066Mhz
but the board only detects half its RAM, because those DIMMs have
Double Sided(DS) chips and seems only Single Sided(SS) ones are
fully detected
- GSkill F3-10666CL9T2-24GBRL(JEDEC,1.50v) 6x4GB kit (4 DIMMs used)
works perfectly at full speed (1333Mhz)
## MRC memory compatibility
- GSkill F3-2133C10D-16GAB(XMP,1.60v) 2x8GB kit works at 1333Mhz
instead of XMP 2133Mhz
- Team Xtreem TXD38G2133HC9NDC01(XMP,1.50v) 2x4GB kit works at
1600Mhz instead of XMP 2133Mhz
- Kingston KVR1066D3N7K2/4G(JEDEC,1.50v) 2x4GB kit works at 1066Mhz
but the board only detects half its RAM, as those DIMMs have
Double Sided(DS) chips and seems only Single Sided(SS) ones are
fully detected
- GSkill F3-10666CL9T2-24GBRL(JEDEC,1.50v) 6x4GB kit (4 DIMMs used)
works perfectly at full speed (1333Mhz)
## Technology
```eval_rst
+------------------+--------------------------------------------------+
| Northbridge | :doc:`../../northbridge/intel/sandybridge/index` |
+------------------+--------------------------------------------------+
| Southbridge | bd82x6x |
+------------------+--------------------------------------------------+
| CPU | model_206ax |
+------------------+--------------------------------------------------+
| Super I/O | Nuvoton NCT6779D |
+------------------+--------------------------------------------------+
| EC | None |
+------------------+--------------------------------------------------+
| Coprocessor | Intel Management Engine |
+------------------+--------------------------------------------------+
```
## Extra resources
- [Flash chip datasheet][W25Q64FVA1Q]
[ASUS P8Z88-M Pro]: https://www.asus.com/Motherboards/P8Z77M_PRO/
[W25Q64FVA1Q]: https://www.winbond.com/resource-files/w25q64fv%20revs%2007182017.pdf
[flashrom]: https://flashrom.org/Flashrom

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# CN81xx Evaluation-board SFF
## Specs
* 3 mini PCIe slots
* 4 SATA ports
* one USB3.0 A connector
* 20Pin JTAG
* 4 Gigabit Ethernet
* 2 SFP+ connectors
* PCIe x4 slot
* UART over USB
* eMMC Flash or MicroSD card slot for on-board storage
* 1 Slot with DDR-4 memory with ECC support
* SPI flash
* MMC and uSD-card
## Flashing coreboot
```eval_rst
+---------------------+----------------+
| Type | Value |
+=====================+================+
| Socketed flash | no |
+---------------------+----------------+
| Model | Micron 25Q128A |
+---------------------+----------------+
| Size | 8 MiB |
+---------------------+----------------+
| In circuit flashing | no |
+---------------------+----------------+
| Package | SOIC-8 |
+---------------------+----------------+
| Write protection | No |
+---------------------+----------------+
| Dual BIOS feature | No |
+---------------------+----------------+
| Internal flashing | ? |
+---------------------+----------------+
```
## Notes about the hardware
1. Cavium connected *GPIO10* to a global reset line.
It's unclear which chips are connected, but at least the PHY and SATA chips
are connected.
2. The 4 QLMs can be configured using DIP switches (SW1). That means only a
subset of of the available connectors is working at time.
3. The boot source can be configure using DIP switches (SW1).
4. The core and system clock frequency can be configured using DIP switches
(SW3 / SW2).
5. The JTAG follows Cavium's own protocol. Support for it is missing in
OpenOCD. You have to use ARMs official hardware and software.
## Technology
```eval_rst
+---------------+----------------------------------------+
| SoC | :doc:`../../soc/cavium/cn81xx/index` |
+---------------+----------------------------------------+
| CPU | Cavium ARMv8-Quadcore `CN81XX`_ |
+---------------+----------------------------------------+
.. _CN81XX: https://www.cavium.com/product-octeon-tx-cn80xx-81xx.html
```
## Picture
![][cn81xx_board]
[cn81xx_board]: cavium_cn81xx_sff_evb.jpg

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