mb/google/sarien: Setup GPIOs again after FSP-S

Currently CoffeeLake FSP is incorrectly modifying GPIO pad configuration
if specific UPD variables are not set as it expects.

This affects the display-related SOC pads with the following UPD variables:

UINT8 DdiPortBHpd; // GPP_E13
UINT8 DdiPortCHpd; // GPP_E14
UINT8 DdiPortDHpd; // GPP_E15
UINT8 DdiPortFHpd; // GPP_E16
UINT8 DdiPortBDdc; // GPP_E18/GPP_E19
UINT8 DdiPortCDdc; // GPP_E20/GPP_E21
UINT8 DdiPortDDdc; // GPP_E22/GPP_E23
UINT8 DdiPortFDdc; // GPP_H16/GPP_H17

Until FSP is fixed to not touch the pad configuration this workaround
will reprogram the GPIO settings after FSP-S step so they are correct
when the OS attempts to use them.

This was found in CoffeLake FSP Gold release:

As well as the current top-of-tree for the FSP sources.

TEST=verify correct GPIO configuration for GPP_E group in the kernel

Change-Id: I19550c4347cf65d409de6a8638619270372c4d0a
Signed-off-by: Duncan Laurie <dlaurie@google.com>
Reviewed-on: https://review.coreboot.org/c/30113
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Lijian Zhao <lijian.zhao@intel.com>
Reviewed-by: Furquan Shaikh <furquan@google.com>
1 file changed
tree: 4e2a9d8a59a43c360bfb4aa731de7c033fde195c
  1. .checkpatch.conf
  2. .clang-format
  3. .gitignore
  4. .gitmodules
  5. .gitreview
  6. 3rdparty/
  8. Documentation/
  10. Makefile
  11. Makefile.inc
  12. README.md
  13. configs/
  14. gnat.adc
  15. payloads/
  16. src/
  17. toolchain.inc
  18. util/

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.


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)


  • 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:


You can contact us directly on the coreboot mailing list:


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.