f0a44ae0eb
Add support for the Intel LPIT table to support reading Low Power Idle
Residency counters by the OS. On platforms supporting S0ix sleep states
there can be two types of residencies:
* CPU package PC10 residency counter (read from MSR via FFH interface)
* PCH SLP_S0 assertion residency counter (read via memory mapped
interface)
With presence of one or both of these counters in the LPIT table, Linux
dynamically adds the corresponding attributes to the cpuidle sysfs
interface, that can be used to read the residency timers:
* /sys/devices/system/cpu/cpuidle/low_power_idle_cpu_residency_us
* /sys/devices/system/cpu/cpuidle/low_power_idle_system_residency_us
The code in src/acpi implements generic LPIT support. Each SoC or
platform has to implement `acpi_fill_lpit` to fill the table with
platform-specific LPI state entries. This is done in this change for
soc/intel/common, while being added as its own compilation unit, so SoCs
not yet using common acpi code (like Skylake) can use it, too.
Reference:
https://uefi.org/sites/default/files/resources/Intel_ACPI_Low_Power_S0_Idle.pdf
Test: Linux adds the cpuidle sysfs interface; Windows with s0ix_enable=1
boots without crashing with an INTERNAL_POWER_ERROR.
- Windows and Linux tested on google/akemi together with CB:49046
- Linux tested on clevo/cml-u, supermicro/x11ssmf together with CB:49046
Change-Id: I816888e8788e2f04c89f20d6ea1654d2f35cf18e
Tested-by: Matt DeVillier <matt.devillier@gmail.com>
Tested-by: Michael Niewöhner <foss@mniewoehner.de>
Signed-off-by: Shaunak Saha <shaunak.saha@intel.com>
Signed-off-by: Michael Niewöhner <foss@mniewoehner.de>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/49045
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Tim Wawrzynczak <twawrzynczak@chromium.org>
coreboot README
coreboot is a Free Software project aimed at replacing the proprietary BIOS (firmware) found in most computers. coreboot performs a little bit of hardware initialization and then executes additional boot logic, called a payload.
With the separation of hardware initialization and later boot logic, coreboot can scale from specialized applications that run directly firmware, run operating systems in flash, load custom bootloaders, or implement firmware standards, like PC BIOS services or UEFI. This allows for systems to only include the features necessary in the target application, reducing the amount of code and flash space required.
coreboot was formerly known as LinuxBIOS.
Payloads
After the basic initialization of the hardware has been performed, any desired "payload" can be started by coreboot.
See https://www.coreboot.org/Payloads for a list of supported payloads.
Supported Hardware
coreboot supports a wide range of chipsets, devices, and mainboards.
For details please consult:
Build Requirements
- make
- gcc / g++
Because Linux distribution compilers tend to use lots of patches. coreboot
does lots of "unusual" things in its build system, some of which break due
to those patches, sometimes by gcc aborting, sometimes - and that's worse -
by generating broken object code.
Two options: use our toolchain (eg. make crosstools-i386) or enable the
ANY_TOOLCHAINKconfig option if you're feeling lucky (no support in this case). - iasl (for targets with ACPI support)
- pkg-config
- libssl-dev (openssl)
Optional:
- doxygen (for generating/viewing documentation)
- gdb (for better debugging facilities on some targets)
- ncurses (for
make menuconfigandmake nconfig) - flex and bison (for regenerating parsers)
Building coreboot
Please consult https://www.coreboot.org/Build_HOWTO for details.
Testing coreboot Without Modifying Your Hardware
If you want to test coreboot without any risks before you really decide to use it on your hardware, you can use the QEMU system emulator to run coreboot virtually in QEMU.
Please see https://www.coreboot.org/QEMU for details.
Website and Mailing List
Further details on the project, a FAQ, many HOWTOs, news, development guidelines and more can be found on the coreboot website:
You can contact us directly on the coreboot mailing list:
https://www.coreboot.org/Mailinglist
Copyright and License
The copyright on coreboot is owned by quite a large number of individual developers and companies. Please check the individual source files for details.
coreboot is licensed under the terms of the GNU General Public License (GPL). Some files are licensed under the "GPL (version 2, or any later version)", and some files are licensed under the "GPL, version 2". For some parts, which were derived from other projects, other (GPL-compatible) licenses may apply. Please check the individual source files for details.
This makes the resulting coreboot images licensed under the GPL, version 2.