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David Hendricks 0d4f97e270 exynos/snow: Move core/memory clock-related and board ID code
This patch moves ARM core and DRAM timing functions around to simplify
the dependencies for system_clock_init().

The original code was architected such that the system_clock_init()
function called other functions to obtain core and memory timings.
Due to the way memory timing information must be obtained on Snow,
which entails decoding platform-specific board straps, the bottom-
up approach resulted in having the low-level clock init code
implicitly depend on board and vendor-specific info:

main()
  ->system_clock_init()
    -> get_arm_ratios()
       -> CPU-specific code
    -> clock_get_mem_timings()
       -> board_get_revision()
          -> read GPIOs (3-state logic)
          -> Decode GPIOs in a vendor-specific manner
       -> Choose memory timings from module-specific look-up table
  ...then proceed to init clocks
...come back to main()

The new approach gathers all board and vendor-specific info in a
more appropriate location and passes it into system_clock_init():
main()
  -> get_arm_ratios()
     -> CPU-specific code
  -> get_mem_timings()
     -> board_get_config()
        -> read GPIOs (3-state logic)
        -> Decode GPIOs in a vendor-specific manner
     -> Choose memory timings from module-specific look-up table
  -> system_clock_init()
...back to main()

Change-Id: Ie237ebff76fc2d8a4d2f4577a226ac3909e4d4e8
Signed-off-by: David Hendricks <dhendrix@chromium.org>
Reviewed-on: http://review.coreboot.org/2271
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
2013-02-06 02:11:14 +01:00
3rdparty@4c0dcf96ae Update 3rdparty mark to latest repository 2013-01-05 01:31:12 +01:00
documentation Update gcov patch in documentation 2013-01-19 01:00:50 +01:00
payloads Fix libpayload xcompile xgcc path 2013-02-01 20:15:47 +01:00
src exynos/snow: Move core/memory clock-related and board ID code 2013-02-06 02:11:14 +01:00
util cbfstool: Add support for 64bit UEFI 2013-02-06 00:37:26 +01:00
.gitignore add a few entries to .gitignore 2013-01-10 22:51:20 +01:00
.gitmodules Add 3rdparty as submodule 2012-05-01 00:08:37 +02:00
.gitreview add .gitreview 2012-11-01 23:13:39 +01:00
COPYING update license template. 2006-08-12 22:03:36 +00:00
Makefile Fix broken scan-build 2012-12-14 22:21:10 +01:00
Makefile.inc armv7: Add 'bootblock' build class. 2013-02-03 05:45:48 +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.