libpayload/keyboard: Revise scancode set and translation config

Some background first: The original XT keyboards used what we call
scancode set #1 today. The PC/AT keyboards introduced scancode set #2,
but for compatibility, its controller translated scancodes back to
set #1 by default. Newer keyboards (maybe all we have to deal with)
also support switching the scancode set.

This means the translation option in the controller and the scancode
set selection in the keyboard have to match. In libpayload, we only
support set #1 scancodes. So we either need the controller's trans-
lation on and set #2 selected in the keyboard, or the controller's
translation off and set #1 selected in the keyboard.

Valid configurations:
* SET #1 + XLATE off
* SET #2 + XLATE on

Both with and without the PC_KEYBOARD_AT_TRANSLATED option, we were
only configuring one of the two settings, leaving room for invalid
configurations. With this change, we try to select scancode set #2
first, which seems to be the most supported one, and configure the
controller's translation accordingly. We try to fall back to set #1
on failure.

We also keep translation disabled during configuration steps to
ensure that the controller doesn't accidentally translate confi-
guration data.

On the coreboot side, we leave the controller's translation at its
default setting, unless DRIVERS_PS2_KEYBOARD is enabled. The latter
enables the translation unconditionally. For QEMU this means that
the option effectively toggles the translation, as QEMU's controller
has it disabled by default. This probably made a lot of earlier
testing inconsistent.

Fixes: commit a95a6bf646 (libpayload/drivers/i8402/kbd: Fix qemu)
       The reset introduced there effectively reverted the scancode
       selection made before (because 2 is the default). It's unclear
       if later changes to the code were only necessary to work
       around it.

Change-Id: Iad85af516a7b9f9c0269ff9652ed15ee81700057
Signed-off-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/46724
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
3 files changed
tree: 3d8602009138107a2015de813f29e72a0accde44
  1. 3rdparty/
  2. configs/
  3. Documentation/
  4. LICENSES/
  5. payloads/
  6. src/
  7. tests/
  8. util/
  9. .checkpatch.conf
  10. .clang-format
  11. .editorconfig
  12. .gitignore
  13. .gitmodules
  14. .gitreview
  15. AUTHORS
  16. COPYING
  17. gnat.adc
  18. MAINTAINERS
  19. Makefile
  20. Makefile.inc
  21. README.md
  22. toolchain.inc
README.md

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_TOOLCHAIN Kconfig 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 menuconfig and make 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:

https://www.coreboot.org

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.