vendorcode/google/chromeos: Support MAC address passthru policy

This change adds support for providing a MAC address that can be used
by the OS network drivers to change the MAC address that a NIC uses.

The Realtek r8152 driver in the Linux kernel supports a MAC address
passthru feature which can result in the dock ethernet port using the
same MAC address that is assigned to the internal NIC.  This is done
by calling an ACPI method at \_SB.AMAC() which returns a formatted
string containing the MAC address for the dock to use.

The Linux kernel implementation can be found at

This is implemented specifically for Chrome OS as it relies on VPD
to determine the MAC address to supply.

The policy which controls where the dock MAC address comes from is
written into RW_VPD property "dock_passthru":
  "dock_mac" or empty: Use MAC address from RO_VPD value "dock_mac"
  "ethernet_mac0": Use MAC address from RO_VPD value "ethernet_mac0"
  "builtin": existing dock MAC address (return nothing)

The MAC address in VPD is the standard format AA:BB:CC:DD:EE:FF and
it must be converted into the string format expected by the OS which
involves some string manipulation which ACPI is not great at handling.

TEST=this was tested on a sarien board by setting the VPD keys to
their expected values and observing if the AMAC() method returns the
expected string.

Change-Id: I3335e5d924155431e299844e2aaace62168294e0
Signed-off-by: Duncan Laurie <>
Tested-by: build bot (Jenkins) <>
Reviewed-by: Lijian Zhao <>
1 file changed
tree: 74432f70393905a40d3687bdf1c7b9fc84817339
  1. .checkpatch.conf
  2. .clang-format
  3. .gitignore
  4. .gitmodules
  5. .gitreview
  6. 3rdparty/
  8. Documentation/
  10. Makefile
  13. configs/
  14. gnat.adc
  15. payloads/
  16. src/
  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 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 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 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.