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Werner Zeh cee8532ce3 intel/fsp_broadwell_de: Remove buggy code for SMBus clock gating
The pch_smbus_init() function contains code to enable clock gating for
the SMBus controller. Unfortunately this code is buggy and leads to a
hanging system with the latest microcode version.
The hang occurs as follows:
The clock gate register is mapped into RCBA space. After reading the
RCBA address from the LPC device config space no mask is applied to the
value (only bits 31..14 are valid while bit 0 is the enable bit). For
this reason the final address is off by one. The old microcodes at least
allowed this unaligned access to the RCBA space. With the latest
microcode this access leads to CPU hang.

Once this is fixed the next issue occurs: After setting the clock
gating bit for SMBus (bit 5) the SMBus controller disappears from the
PCI bus completely and hence no usage of it is possible anymore.

To fix this issue the clock gating code is completely removed as it was
intentionally meant to enable clock gating on the SMB_CLK line and not
the clock gating on the PCIe interface of the SMBus controller.

This issue is known already and was discussed on the mailinglist:

[coreboot] BDX-DE PCI init fail
https://mail.coreboot.org/pipermail/coreboot/2018-January/085908.html

TEST=Boot mc_bdx1 with microcode version M1050663_07000012.

Change-Id: Icb86f4516f8a6e72552a44618737e682b0fdef33
Signed-off-by: Werner Zeh <werner.zeh@siemens.com>
Reviewed-on: https://review.coreboot.org/25652
Reviewed-by: David Hendricks <david.hendricks@gmail.com>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
2018-04-16 02:25:06 +00:00
3rdparty 3rdparty/libgfxinit: Update submodule pointer 2018-04-13 16:42:48 +00:00
Documentation Documentation: Fix a bunch of typos 2018-04-10 10:50:06 +00:00
configs configs: Add intel/harcuvar FSP 2.0 sample configuration 2017-10-04 02:56:33 +00:00
payloads arch/arm64/armv8/mmu: Add support for 48bit VA 2018-03-23 04:09:50 +00:00
src intel/fsp_broadwell_de: Remove buggy code for SMBus clock gating 2018-04-16 02:25:06 +00:00
util util/cbfstool: Print all supported architectures 2018-04-11 14:12:00 +00:00
.checkpatch.conf .checkpatch.conf: Ignore CORRUPTED_PATCH lint 2017-10-29 10:11:58 +00:00
.clang-format
.gitignore util/blobtool: rename to bincfg 2018-01-18 13:47:20 +00:00
.gitmodules Set up 3rdparty/libgfxinit 2016-10-29 01:35:03 +02:00
.gitreview
COPYING
MAINTAINERS MAINTAINERS: change second PC Engines maintainer 2018-03-21 18:25:49 +00:00
Makefile Makefile: Add filelist to help 2018-01-29 15:35:11 +00:00
Makefile.inc device: Include devicetree in SMM stage 2018-02-22 09:55:19 +00:00
README README: Update requirements 2017-06-27 17:04:32 +00:00
gnat.adc gnat.adc: Do not generate assertion code for Refined_Post 2016-10-29 01:33:31 +02:00
toolchain.inc toolchain: Always use GCC for Ada sources 2017-09-23 10:57:40 +00:00

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 https://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:

 * https://www.coreboot.org/Supported_Motherboards
 * https://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)
 * pkg-config
 * libssl-dev (openssl)

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 https://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 https://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:

  https://www.coreboot.org

You can contact us directly on the coreboot mailing list:

  https://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.