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Julius Werner 2296479dfd libpayload: cbfs: Add cbfs_handle API for more fine-grained accesses
The libpayload CBFS APIs are pretty old and clunky, primarily because of
the way the cbfs_media struct may or may not be passed in and may be
initialized inside the API calls in a way that cannot be passed back out
again. Due to this, the only real CBFS access function we have always
reads a whole file with all metadata, and everything else has to build
on top of that. This makes certain tasks like reading just a file
attribute very inefficient on non-memory-mapped platforms (because you
always have to map the whole file).

This patch isn't going to fix the world, but will allow a bit more
flexibility by bolting a new API on top which uses a struct cbfs_handle
to represent a found but not yet read file. A cbfs_handle contains a
copy of the cbfs_media needed to read the file, so it can be kept and
passed around to read individual parts of it after the initial lookup.
The existing (non-media) legacy API is retained for backwards
compatibility, as is cbfs_file_get_contents() (which is most likely what
more recent payloads would have used, and also a good convenience
wrapper for the most simple use case), but they are now implemented on
top of the new API.

TEST=Booted Oak, made sure that firmware screens and software sync
worked okay.

Change-Id: I269f3979e77ae691ee9d4e1ab564eff6d45b7cbe
Signed-off-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: https://review.coreboot.org/14810
Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
2016-05-17 22:48:28 +02:00
3rdparty 3rdparty/blobs: add more Qualcomm stubs 2016-05-10 21:22:28 +02:00
Documentation lib: remove FLASHMAP_OFFSET config variable 2016-05-11 21:32:44 +02:00
payloads libpayload: cbfs: Add cbfs_handle API for more fine-grained accesses 2016-05-17 22:48:28 +02:00
src intel/sch: Merge northbridge and southbridge in src/soc 2016-05-17 21:38:17 +02:00
util sconfig: Add a new generic device type 2016-05-16 19:49:59 +02:00
.clang-format Provide coreboot coding style formalisation file for clang-format 2015-11-10 00:49:03 +01:00
.gitignore .gitignore: add build and libpayload dirs for nvramcui payload 2016-05-03 04:16:45 +02:00
.gitmodules git modules: rename git submodules to avoid hierarchies 2016-02-11 20:55:55 +01:00
.gitreview
COPYING
MAINTAINERS MAINTAINERS: Add maintainer for Pineview & x4x chipsets & boards 2016-04-19 19:25:59 +02:00
Makefile Makefile: Update payload clean targets 2016-03-09 17:01:56 +01:00
Makefile.inc xip: Do not pass --xip for early stages if CAR supports code execution 2016-05-09 05:01:58 +02:00
README README: improve description of compiler requirements 2015-07-30 05:11:33 +02:00
toolchain.inc toolchain.inc: test IASL by version string instead of number 2016-03-04 16:36:25 +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.