No description
f296c94522
To ensure that the command1 write which sets the "go" bit completes before other reads to the device. Otherwise, there's a race condition where those register values might still have their values from the last transfer. With different SPI clock frequencies, that could lead to spi_delay being told there were negative bytes still to send. Its expected delay would wrap to a negative value, that was passed to udelay, and the system would sit there for 4 seconds not doing anything. BUG=None TEST=Built and booted on nyan. Set the SPI bus frequency to a value which was causing the 4+ second delay and verified that it no longer happened. BRANCH=None Original-Change-Id: I8b4090efc69f34d0413e3f63c59c1825dd151cec Original-Signed-off-by: Gabe Black <gabeblack@google.com> Original-Reviewed-on: https://chromium-review.googlesource.com/193347 Original-Reviewed-by: Gabe Black <gabeblack@chromium.org> Original-Commit-Queue: Gabe Black <gabeblack@chromium.org> Original-Tested-by: Gabe Black <gabeblack@chromium.org> (cherry picked from commit d7ea9febdf2c5942f81607ee6ded786c9a8954bb) Signed-off-by: Marc Jones <marc.jones@se-eng.com> Change-Id: I095bfc745eda37b8e666475ceb41684152f3709a Reviewed-on: http://review.coreboot.org/7737 Tested-by: build bot (Jenkins) Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org> |
||
---|---|---|
3rdparty@9f68e20e5e | ||
documentation | ||
payloads | ||
src | ||
util | ||
.gitignore | ||
.gitmodules | ||
.gitreview | ||
COPYING | ||
Makefile | ||
Makefile.inc | ||
README | ||
toolchain.inc |
------------------------------------------------------------------------------- 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.