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David Hendricks aee444f453 exynos5250: ungate the product ID register
This makes sure that the product ID (PRO_ID) register can be read
when the OS kernel is figuring out what kind of CPU it's running on.

For historical reference, the original U-Boot code seems to have
worked basically by accident here. The hardware has a quirk where by
reading the value before gating the IP block keeps the value
persistent. U-Boot reads the chip ID early on to distinguish between
chip family, but we do not mix code the same way so we do not read
the chip ID. Since the value has been read before the clock gating
happens, the value remains available for the kernel to use during the
decompression stage. We don't want to rely on that behavior when using
coreboot. Instead the kernel should gate unused IPs.

(credit to Gabe for finding symptom in the kernel)

Change-Id: Iaa21e6e718b9000b5558f568020f393779fd208e
Signed-off-by: Gabe Black <gabeblack@chromium.org>
Signed-off-by: David Hendricks <dhendrix@chromium.org>
Reviewed-on: http://review.coreboot.org/3121
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
Tested-by: build bot (Jenkins)
2013-04-23 03:20:44 +02:00
3rdparty@ba8caa30bd Update 3rdparty mark to latest repository 2013-03-15 19:09:08 +01:00
documentation documentation: Complete the AMD-S3.txt 2013-04-16 02:31:08 +02:00
payloads Eliminate use of pointers in coreboot table 2013-04-20 05:18:15 +02:00
src exynos5250: ungate the product ID register 2013-04-23 03:20:44 +02:00
util superiotool: add CR dump for W83627UHG = NCT6627UD 2013-04-22 17:07:13 +02:00
.gitignore add a few entries to .gitignore 2013-01-10 22:51:20 +01:00
.gitmodules gitmodules: Ignore 3rdparty in "diff family" 2013-03-16 04:07:14 +01:00
.gitreview add .gitreview 2012-11-01 23:13:39 +01:00
COPYING update license template. 2006-08-12 22:03:36 +00:00
Makefile build system: Retire REQUIRES_BLOB 2013-02-19 11:00:41 +01:00
Makefile.inc rmodule: add rmodules class and new type 2013-03-18 20:46:40 +01:00
README Update README with newer version of the text from the web page 2011-06-15 10:16:33 +02:00

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
------------------

 * gcc / g++
 * make

Optional:

 * doxygen (for generating/viewing documentation)
 * iasl (for targets with ACPI support)
 * gdb (for better debugging facilities on some targets)
 * ncurses (for 'make menuconfig')
 * 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.