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Duncan Laurie 7f3156dad6 skylake: gpio: Add support for setting 1.8V tolerant
Add the voltage tolerance GPIO attribute for configuring I2C/I2S buses
that are at 1.8V.  This is currently done by passing in a value to FSP
but it is needed earlier than FSP if the I2C bus is used in verstage.

This does not remove the need for the FSP input parameter, that is
still required so FSP doesn't disable what has been set in coreboot.
The mainboards that are affected are updated in this commit.

This was tested by exercising I2C transactions to the 1.8V codec while
in verstage on the google/chell mainboard.

Signed-off-by: Duncan Laurie <dlaurie@chromium.org>
Change-Id: I93d22c2e3bc0617c87f03c37a8746e22a112cc9c
Reviewed-on: https://review.coreboot.org/15103
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Tested-by: build bot (Jenkins)
2016-06-09 17:07:26 +02:00
3rdparty 3rdparty/blobs: add more Qualcomm stubs 2016-05-10 21:22:28 +02:00
Documentation Documentation/Intel/Board: Add Galileo checklist 2016-06-02 02:47:29 +02:00
payloads SeaBIOS: Add option to include a bootorder file in cbfs 2016-06-08 19:17:04 +02:00
src skylake: gpio: Add support for setting 1.8V tolerant 2016-06-09 17:07:26 +02:00
util inteltool: handle unsafe dumping of graphics registers 2016-06-08 22:35:57 +02:00
.clang-format
.gitignore .gitignore: add build and libpayload dirs for nvramcui payload 2016-05-03 04:16:45 +02:00
.gitmodules git modules: rename git submodules to avoid hierarchies 2016-02-11 20:55:55 +01:00
.gitreview
COPYING
MAINTAINERS MAINTAINERS: Add myself for Apollolake SoC, FSP2.0, and Amenia mb 2016-05-26 23:52:57 +02:00
Makefile Makefile: Make printall target more readable 2016-06-07 23:31:17 +02:00
Makefile.inc Add Board Checklist Support 2016-06-03 17:29:13 +02:00
README
toolchain.inc toolchain.inc: test IASL by version string instead of number 2016-03-04 16:36:25 +01:00

README

-------------------------------------------------------------------------------
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 http://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:

 * http://www.coreboot.org/Supported_Motherboards
 * http://www.coreboot.org/Supported_Chipsets_and_Devices


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)

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 http://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 http://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:

  http://www.coreboot.org

You can contact us directly on the coreboot mailing list:

  http://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.