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Patrick Rudolph d912f1d4f9 nb/intel/sandybridge/raminit: Adjust timB to prevent overflow
Improved version of
I1a115a45d5febf351d89721ece79eaf43f7ee8a0

The first version wasn't well tested due to the lack of hardware
and it was to aggressive.

With timC being direct function of timB's 6 LSBs it's critical to match
timC and timB.
Some tests increments the value of timB by a small value,
which might cause the 6bit value to overflow, if it's close
to 0x3F.
Increment the value by a small offset if it's likely
to overflow, to make sure it won't overflow while running
tests and bricks the system due to a non matching timC.

In comparission to the first attempt, only 4 out of 128 timB values
are considered bad.

Needs test on real hardware !

Fixes a "edge write discovery failed" on my test system.

Test system:
 * Intel IvyBridge
 * Gigabyte GA-B75M-D3H

Change-Id: If9abfc5f92e20a8f39c6f50cc709ca1cedf6827d
Signed-off-by: Patrick Rudolph <siro@das-labor.org>
Reviewed-on: https://review.coreboot.org/13714
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
2016-02-26 20:04:30 +01:00
3rdparty arch/arm64: Compile arm-trusted-firmware with coreboot timestamp 2016-02-18 11:08:01 +01:00
Documentation Documentation/Intel: Add minimal APCI and TempRamExit documentation 2016-02-24 15:55:42 +01:00
payloads u-boot: Make sure targets aren't duplicated 2016-02-24 19:22:52 +01:00
src nb/intel/sandybridge/raminit: Adjust timB to prevent overflow 2016-02-26 20:04:30 +01:00
util nvramtool: Print computed and stored checksum in case of mismatch. 2016-02-26 07:02:01 +01:00
.clang-format Provide coreboot coding style formalisation file for clang-format 2015-11-10 00:49:03 +01:00
.gitignore Payloads: Add U-Boot as a coreboot-payload 2016-02-18 20:53:42 +01:00
.gitmodules git modules: rename git submodules to avoid hierarchies 2016-02-11 20:55:55 +01:00
.gitreview
COPYING
MAINTAINERS MAINTAINERS: Designate Intel maintainers for FSP 1.0 Baytrail 2015-12-30 20:06:52 +01:00
Makefile build system: avoid setting HOSTCC to " gcc" 2016-02-02 14:35:11 +01:00
Makefile.inc cbfs: Add LZ4 in-place decompression support for pre-RAM stages 2016-02-22 21:38:37 +01:00
README README: improve description of compiler requirements 2015-07-30 05:11:33 +02:00
toolchain.inc power8: try to fix toolchain.inc for power8. 2016-02-17 23:43:38 +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.