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Hung-Te Lin d04b388381 libpayload: cbgfx: Support buffered I/O
For payloads with UI based on CBGFX, they usually start by calling
clear_canvas or clear_screen and then draw the UI elements. However,
that makes the screen flicker.

A typical solution is to identify and minimize the area to redraw.
However for payloads with complicated UI and do not care about latency,
an alternative is to enable buffered I/O.

The new enable_graphics_buffer() will redirect all graphics I/O
into an invisible working buffer. To flush (redraw) the buffer to the
real screen, call flush_graphics_buffer(). To stop buffering, call
disable_graphics_buffer().

BUG=None
TEST=Add the enable, flush and disable calls to payload 'depthcharge',
     built a firmware and boots into Chrome OS recover UI. No more
     flickering. The average rendering time on x86 platform is 1.2ms.

Change-Id: Id60a2824fd9e164feae16b92b68b003beabea8d3
Signed-off-by: Hung-Te Lin <hungte@chromium.org>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/44654
Reviewed-by: Julius Werner <jwerner@chromium.org>
Reviewed-by: Yu-Ping Wu <yupingso@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
2020-08-28 21:40:58 +00:00
3rdparty 3rdparty/vboot: Update to latest master 2020-08-20 21:06:27 +00:00
Documentation Doc/soc/intel: Add info about microcode updates 2020-08-26 07:36:12 +00:00
LICENSES drivers: Use SPDX identifiers 2020-05-25 22:19:21 +00:00
configs configs: Build test experimental x86_64 code 2020-08-19 10:54:45 +00:00
payloads libpayload: cbgfx: Support buffered I/O 2020-08-28 21:40:58 +00:00
src mb/google/zork: Modify USI_RESET_L GPIO 140 to be active to low 2020-08-28 19:04:09 +00:00
tests tests: Improve test_skip_atoi() in /lib/string-test test case 2020-07-12 19:38:39 +00:00
util util: Add memory parts needed by zork boards 2020-08-28 14:29:44 +00:00
.checkpatch.conf .checkpatch.conf: Ignore a few more warnings 2018-08-13 12:23:24 +00:00
.clang-format lint/clang-format: set to 96 chars per line 2019-06-13 20:14:00 +00:00
.editorconfig Add .editorconfig file 2019-09-10 12:52:18 +00:00
.gitignore cbfstool: Build vboot library 2020-03-23 08:34:23 +00:00
.gitmodules Add qc_blobs repository 2020-06-30 08:57:03 +00:00
.gitreview
AUTHORS AUTHORS, util/: Drop individual copyright notices 2020-05-09 21:21:32 +00:00
COPYING
MAINTAINERS MAINTAINERS: Update soc/mediatek maintainership 2020-08-26 07:35:21 +00:00
Makefile build system: Rely on xcompile for HOSTCC and HOSTCXX 2020-07-08 08:53:46 +00:00
Makefile.inc Makefile.inc: Remove redundant warning flag 2020-08-17 07:08:31 +00:00
README.md README.md: Remove link to deprecated wiki 2019-11-16 20:39:55 +00:00
gnat.adc treewide: Remove "this file is part of" lines 2020-05-11 17:11:40 +00:00
toolchain.inc Remove MAYBE_STATIC_BSS and ENV_STAGE_HAS_BSS_SECTION 2020-05-26 15:04:08 +00:00

README.md

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:

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

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.