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David Hendricks 032c843817 spi_flash: Move (de-)assertion of /CS to single location
This consolidates all calls to spi_claim_bus() and spi_release_bus()
to a single location where spi_xfer() is called. This avoids confusing
(and potentially redundant) calls that were being done throughout the
generic spi_flash.c functions and chip-specific functions.

I don't think the current approach could even work since many chip
drivers assert /CS once and then issue multiple commands such as page
program followed by reading the status register. I suspect the reason
we didn't notice it on x86 is because the ICH/PCH handled each
individual command correctly (spi_claim_bus() and spi_release_bus()
are noops) in spite of the broken code.

BUG=none
BRANCH=none
TEST=tested on nyan and link
Signed-off-by: David Hendricks <dhendrix@chromium.org>

Original-Change-Id: I3257e2f6a2820834f4c9018069f90fcf2bab05f6
Original-Reviewed-on: https://chromium-review.googlesource.com/194510
Original-Reviewed-by: David Hendricks <dhendrix@chromium.org>
Original-Commit-Queue: David Hendricks <dhendrix@chromium.org>
Original-Tested-by: David Hendricks <dhendrix@chromium.org>
(cherry picked from commit d3394d34fb49e9e252f67371674d5b3aa220bc9e)
Signed-off-by: Marc Jones <marc.jones@se-eng.com>

Change-Id: Ieb62309b18090d8f974f91a6e448af3d65dd3d1d
Reviewed-on: http://review.coreboot.org/7829
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
2014-12-17 04:51:28 +01:00
3rdparty@9f68e20e5e 3rdparty: Update to latest commit in blobs repository 2014-12-01 08:50:32 +01:00
documentation mkelfimage: remove 2014-10-08 14:27:24 +02:00
payloads arm: Fix minor mistake in cache maintenance assembly 2014-12-15 23:27:41 +01:00
src spi_flash: Move (de-)assertion of /CS to single location 2014-12-17 04:51:28 +01:00
util inteltool: Start adding Bay Trail 2014-12-16 00:42:13 +01:00
.gitignore .gitignore: add the doxygen directory. 2014-12-14 23:30:45 +01:00
.gitmodules nvidia/cbootimage: avoid upstream's build system 2014-10-02 10:26:58 +02:00
.gitreview
COPYING
Makefile Makefile: Tone down some clang warnings, some are unproductive 2014-12-12 13:29:47 +01:00
Makefile.inc build system: fix alignment function 2014-12-03 15:50:28 +01:00
README
toolchain.inc Add UCB RISCV support for architecture, soc, and emulation mainboard.. 2014-12-01 19:06:43 +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
------------------

 * 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.