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Julius Werner 83d1ba7e3d tegra: i2c: Add a timeout to I2C bit clear recovery mechanism
Our tests with the I2C bit clear mechanism (recovering from "lost
arbitration" errors) show that the bit clear hardware does not work
correctly in some situations. When a wedged slave device tries to send
more than one 0-to-1-to-0 transition to the host (e.g. leftover bits
from an aborted read), the controller never transitions the BC_ENABLE
bit back to zero.

This patch adds a long timeout to the bit clear code that waits for
register transitions as a safeguard. This way, We will still eventually
exit the function (probably followed by a reboot). Our tests show that
this will recover from all conditions after at most a few reboots.

BRANCH=nyan
BUG=chrome-os-partner:28323
TEST=Ran wedge_ack and wedge_read tests with software_i2c patch, system
recovered as expected in all cases.

Original-Change-Id: I6c37119130e1240e1ef3a5944582abbcd2e39ff0
Original-Signed-off-by: Julius Werner <jwerner@chromium.org>
Original-Reviewed-on: https://chromium-review.googlesource.com/200265
Original-Reviewed-by: Tom Warren <twarren@nvidia.com>
Original-Reviewed-by: Gabe Black <gabeblack@chromium.org>
(cherry picked from commit 4c8d0af25cf107a38c856b38067b8f2f74384f22)
Signed-off-by: Marc Jones <marc.jones@se-eng.com>

Change-Id: I600d5c9a8e68719cf8795c083c5fac63f626f5bf
Reviewed-on: http://review.coreboot.org/7948
Tested-by: build bot (Jenkins)
Reviewed-by: David Hendricks <dhendrix@chromium.org>
2014-12-30 22:07:57 +01:00
3rdparty@a8b0c52850 3rdparty: Update to latest commit in blobs repository 2014-12-28 16:04:03 +01:00
documentation mkelfimage: remove 2014-10-08 14:27:24 +02:00
payloads libpayload: fix printf handling of unsigned long long 2014-12-30 20:54:23 +01:00
src tegra: i2c: Add a timeout to I2C bit clear recovery mechanism 2014-12-30 22:07:57 +01:00
util cbmem: use a single id to name mapping table 2014-12-30 19:17:47 +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 add .gitreview 2012-11-01 23:13:39 +01:00
COPYING update license template. 2006-08-12 22:03:36 +00:00
Makefile Makefile: Tone down some clang warnings, some are unproductive 2014-12-12 13:29:47 +01:00
Makefile.inc intel: Fix UPDATE-FIT step in build 2014-12-28 19:58:59 +01:00
README Update README with newer version of the text from the web page 2011-06-15 10:16:33 +02:00
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.