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Timothy Pearson 45ded7df03 amd/amdmct/mct_ddr3: Improve SPD DIMM detect reliability
Upon bootup the hardware reads at minimum 256 * 16 bytes (4Kb, or 32KB) over
I2C on a system with all DIMM slots populated.  If even one of those reads
has a single flipped bit in it (due to EMI, cross coupling with another trace,
 or just poor margins on some cheap DIMM) the system will hang and require a
hard reset.  In practice I've seen failure rates as high as 1 failed boot in
50 due to this issue, granted with cheap DIMMs, but even so retrying the read
resolves the corruption issue.

I2C is not designed for continuous data transmission with high reliability, and
there is no hardware error checking, therefore a single retry when transferring
this amount of data makes sense.

Change-Id: Ifab63eca2233c63a6a42ab8b7e742f8e47fb2a09
Signed-off-by: Timothy Pearson <tpearson@raptorengineeringinc.com>
Reviewed-on: http://review.coreboot.org/11975
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <pgeorgi@google.com>
2015-11-11 01:20:03 +01:00
3rdparty 3rdparty/vboot: update to current master 2015-10-28 22:28:16 +01:00
Documentation tree: drop last paragraph of GPL copyright header 2015-10-31 21:37:39 +01:00
payloads libpayload/udc: dwc2: Add handler for add_strings 2015-11-10 14:10:39 +01:00
src amd/amdmct/mct_ddr3: Improve SPD DIMM detect reliability 2015-11-11 01:20:03 +01:00
util utils/scripts: Add microcode conversion tool 2015-11-10 18:46:04 +01:00
.clang-format Provide coreboot coding style formalisation file for clang-format 2015-11-10 00:49:03 +01:00
.gitignore .gitignore: adapt to new buildgcc version 2015-09-28 20:05:14 +00:00
.gitmodules submodules: add arm-trusted-firmware third-party repository 2015-06-23 08:20:24 +02:00
.gitreview add .gitreview 2012-11-01 23:13:39 +01:00
COPYING
MAINTAINERS MAINTAINERS: Fix format for file entries (F:) 2015-10-22 20:20:48 +02:00
Makefile Add cscope/ctags generation for the current project 2015-07-30 05:21:28 +02:00
Makefile.inc arm64: remove secmon 2015-11-07 03:28:06 +01:00
README README: improve description of compiler requirements 2015-07-30 05:11:33 +02:00
toolchain.inc tree: drop last paragraph of GPL copyright header 2015-10-31 21:37:39 +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
------------------

 * make
 * gcc / g++
   Because Linux distribution compilers tend to use lots of patches. coreboot
   does lots of "unusual" things in its build system, some of which break due
   to those patches, sometimes by gcc aborting, sometimes - and that's worse -
   by generating broken object code.
   Two options: use our toolchain (eg. make crosstools-i386) or enable the
   ANY_TOOLCHAIN Kconfig option if you're feeling lucky (no support in this
   case).
 * iasl (for targets with ACPI support)

Optional:

 * doxygen (for generating/viewing documentation)
 * gdb (for better debugging facilities on some targets)
 * ncurses (for 'make menuconfig' and 'make nconfig')
 * 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.