35599f9a66
Recommonmark has been deprecated since 2021 [1] and the last release was
over 3 years ago [2]. As per their announcement, Markedly Structured
Text (MyST) Parser [3] is the recommended replacement.
For the most part, the existing documentation is compatible with MyST,
as both parsers are built around the CommonMark flavor of Markdown. The
main difference that affects coreboot is how the Sphinx toctree is
generated. Recommonmark has a feature called auto_toc_tree, which
converts single level lists of references into a toctree:
* [Part 1: Starting from scratch](part1.md)
* [Part 2: Submitting a patch to coreboot.org](part2.md)
* [Part 3: Writing unit tests](part3.md)
* [Managing local additions](managing_local_additions.md)
* [Flashing firmware](flashing_firmware/index.md)
MyST Parser does not provide a replacement for this feature, meaning the
toctree must be defined manually. This is done using MyST's syntax for
Sphinx directives:
```{toctree}
:maxdepth: 1
Part 1: Starting from scratch <part1.md>
Part 2: Submitting a patch to coreboot.org <part2.md>
Part 3: Writing unit tests <part3.md>
Managing local additions <managing_local_additions.md>
Flashing firmware <flashing_firmware/index.md>
```
Internally, auto_toc_tree essentially converts lists of references into
the Sphinx toctree structure that the MyST syntax above more directly
represents.
The toctrees were converted to the MyST syntax using the following
command and Python script:
`find ./ -iname "*.md" | xargs -n 1 python conv_toctree.py`
```
import re
import sys
in_list = False
f = open(sys.argv[1])
lines = f.readlines()
f.close()
with open(sys.argv[1], "w") as f:
for line in lines:
match = re.match(r"^[-*+] \[(.*)\]\((.*)\)$", line)
if match is not None:
if not in_list:
in_list = True
f.write("```{toctree}\n")
f.write(":maxdepth: 1\n\n")
f.write(match.group(1) + " <" + match.group(2) + ">\n")
else:
if in_list:
f.write("```\n")
f.write(line)
in_list = False
if in_list:
f.write("```\n")
```
While this does add a little more work for creating the toctree, this
does give more control over exactly what goes into the toctree. For
instance, lists of links to external resources currently end up in the
toctree, but we may want to limit it to pages within coreboot.
This change does break rendering and navigation of the documentation in
applications that can render Markdown, such as Okular, Gitiles, or the
GitHub mirror. Assuming the docs are mainly intended to be viewed after
being rendered to doc.coreboot.org, this is probably not an issue in
practice.
Another difference is that MyST natively supports Markdown tables,
whereas with Recommonmark, tables had to be written in embedded rST [4].
However, MyST also supports embedded rST, so the existing tables can be
easily converted as the syntax is nearly identical.
These were converted using
`find ./ -iname "*.md" | xargs -n 1 sed -i "s/eval_rst/{eval-rst}/"`
Makefile.sphinx and conf.py were regenerated from scratch by running
`sphinx-quickstart` using the updated version of Sphinx, which removes a
lot of old commented out boilerplate. Any relevant changes coreboot had
made on top of the previous autogenerated versions of these files were
ported over to the newly generated file.
From some initial testing the generated webpages appear and function
identically to the existing documentation built with Recommonmark.
TEST: `make -C util/docker docker-build-docs` builds the documentation
successfully and the generated output renders properly when viewed in
a web browser.
[1] https://github.com/readthedocs/recommonmark/issues/221
[2] https://pypi.org/project/recommonmark/
[3] https://myst-parser.readthedocs.io/en/latest/
[4] https://doc.coreboot.org/getting_started/writing_documentation.html
Change-Id: I0837c1722fa56d25c9441ea218e943d8f3d9b804
Signed-off-by: Nicholas Chin <nic.c3.14@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/73158
Reviewed-by: Matt DeVillier <matt.devillier@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
4.0 KiB
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
:maxdepth: 1
Flashing internally <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
:maxdepth: 1
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:
:maxdepth: 1
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.
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:
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
flashrom --ifd -i bios -w coreboot.rom -p <programmer>
TODO explain FMAP regions, normal/fallback mechanism, flash lock mechanisms