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Julius Werner f8f7fd56e9 google/gru: Ensure correct pull resistors for special-function pins
Several of the special function pins we're using in firmware have a
pre-assigned pull-up or pull-down on power-on reset. We don't want those
to interfere with any of the signaling we're trying to do on those pins,
so this patch disables them.

Also do some house-cleaning to group the bootblock code better, and
change the setup code for all SPI and I2C buses to first initialize the
controller and then mux the pins... I assume this might be a little
safer (in case the controller peripheral has some pins in a weird state
before it gets fully initialized, we don't want to mux it through too
early).

BRANCH=None
BUG=chrome-os-partner:52526
TEST=Booted Kevin.

Change-Id: I6bcf2b9a5dc686f2b6f82bd80fc9a1a245661c47
Signed-off-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/382532
2016-09-09 00:04:25 -07:00
Documentation UPSTREAM: Documentation: add start of documentation of the build system 2016-08-15 07:36:05 -07:00
payloads UPSTREAM: iPXE: Update stable version to the last commit of July 2016 2016-09-07 11:31:44 -07:00
src google/gru: Ensure correct pull resistors for special-function pins 2016-09-09 00:04:25 -07:00
util UPSTREAM: util/lint: Update to latest checkpatch.pl 2016-09-07 00:16:42 -07:00
.checkpatch.conf UPSTREAM: Update .checkpatch.conf 2016-09-06 13:26:39 -07:00
.clang-format Provide coreboot coding style formalisation file for clang-format 2015-11-10 00:49:03 +01:00
.gitignore UPSTREAM: .gitignore: Add coreinfo build residue, defconfig 2016-09-06 13:26:36 -07:00
.gitmodules Make upstream tree CrOS SDK friendly 2016-05-12 15:42:17 -06:00
.gitreview add .gitreview 2012-11-01 23:13:39 +01:00
COMMIT-QUEUE.ini Make upstream tree CrOS SDK friendly 2016-05-12 15:42:17 -06:00
COPYING update license template. 2006-08-12 22:03:36 +00:00
MAINTAINERS UPSTREAM: MAINTAINERS: Add myself as tpm support maintainer. 2016-07-07 19:29:05 -07:00
Makefile UPSTREAM: crossgcc: Add gnumake target so that make can be built directly 2016-08-15 18:35:59 -07:00
Makefile.inc UPSTREAM: Makefile.inc: Use $(MAINBOARDDIR) 2016-09-07 00:16:17 -07:00
PRESUBMIT.cfg Make upstream tree CrOS SDK friendly 2016-05-12 15:42:17 -06:00
README UPSTREAM: Remove extra newlines from the end of all coreboot files. 2016-08-04 23:36:56 -07:00
toolchain.inc UPSTREAM: toolchain.inc: Update 'required toolchain' error text 2016-08-11 20:40:01 -07:00

-------------------------------------------------------------------------------
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.