coreboot-kgpe-d16/payloads/libpayload
Aaron Durbin 152e5a03a1 libpayload: honor TSC information under CONFIG_LP_TIMER_RDTSC
When CONFIG_LP_TIMER_RDTSC is enabled honor the TSC information
exported in the coreboot tables as the cpu_khz frequency. That
allows get_cpu_speed() not to be called which currently relies
on the 8254 PIT. As certain x86 platforms allow that device
to be optional or turned off for power saving reasons, allow
a path where get_cpu_speed() is no longer called. Additionally,
this approach also allows the libpayload to not duplicate logic
that already exists in coreboot.

BUG=chrome-os-partner:50214
BRANCH=glados
TEST=Confirmed in payload TSC frequency is honored instead of
     using get_cpu_speed().

Change-Id: Ib8993afdfb49065d43de705d6dbbdb9174b6f2c4
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: https://review.coreboot.org/13671
Tested-by: build bot (Jenkins)
Reviewed-by: Martin Roth <martinroth@google.com>
Reviewed-by: Andrey Petrov <andrey.petrov@intel.com>
2016-02-19 19:50:25 +01:00
..
arch libpayload: honor TSC information under CONFIG_LP_TIMER_RDTSC 2016-02-19 19:50:25 +01:00
bin libpayload: Rename PDCurses-3.4 to PDCurses 2015-11-11 21:38:48 +01:00
configs libpayload/configs/config.veyron: Use CONFIG_LP_8250_SERIAL_CONSOLE 2015-12-06 22:24:30 +01:00
crypto libpayload: Make Kconfig bools use IS_ENABLED() 2015-06-30 18:55:15 +02:00
curses libpayload: PDCurses: Remove trailing whitespace 2015-11-20 16:27:36 +01:00
drivers libpayload: use 32bit access when accessing 4byte wide uart registers 2016-02-09 21:53:42 +01:00
gdb tree: drop last paragraph of GPL copyright header 2015-10-31 21:37:39 +01:00
include libpayload: honor TSC information under CONFIG_LP_TIMER_RDTSC 2016-02-19 19:50:25 +01:00
libc libpayload: honor TSC information under CONFIG_LP_TIMER_RDTSC 2016-02-19 19:50:25 +01:00
libcbfs libpayload: get cbfs offset & size for default media from lib_sysinfo 2015-12-03 14:16:34 +01:00
liblz4 libpayload: lz4: Add output overrun check to incompressible case 2015-07-21 21:27:42 +02:00
liblzma lzma: Return correct amount of decompressed bytes 2015-07-06 09:40:37 +02:00
libpci
sample
tests
Doxyfile
Kconfig libpayload: Add timer driver for armada38x 2016-02-04 11:32:22 +01:00
LICENSES libpayload: Add LZ4 decompression algorithm 2015-07-09 00:10:16 +02:00
LICENSE_GPL
Makefile libpayload: Add missing autoconf dependency 2015-09-10 09:18:12 +00:00
Makefile.inc libpayload: Use CONFIG_LP_CCACHE instead of CONFIG_CCACHE 2015-08-09 21:02:37 +02:00
README

README

-------------------------------------------------------------------------------
libpayload README
-------------------------------------------------------------------------------

libpayload is a minimal library to support standalone payloads
that can be booted with firmware like coreboot. It handles the setup
code, and provides common C library symbols such as malloc() and printf().

Note: This is _not_ a standard library for use with an operating system,
rather it's only useful for coreboot payload development!
See http://coreboot.org for details on coreboot.


Installation
------------

 $ git clone http://review.coreboot.org/p/coreboot.git

 $ cd coreboot/payloads/libpayload

 $ make menuconfig

 $ make

 $ sudo make install (optional, will install into /opt per default)

As libpayload is for 32bit x86 systems only, you might have to install the
32bit libgcc version, otherwise your payloads will fail to compile.
On Debian systems you'd do 'apt-get install gcc-multilib' for example.


Usage
-----

Here's an example of a very simple payload (hello.c) and how to build it:

 #include <libpayload.h>

 int main(void)
 {
     printf("Hello, world!\n");
     return 0;
 }

Building the payload using the 'lpgcc' compiler wrapper:

 $ lpgcc -o hello.elf hello.c

Please see the sample/ directory for details.


Website and Mailing List
------------------------

The main website is http://www.coreboot.org/Libpayload.

For additional information, patches, and discussions, please join the
coreboot mailing list at http://coreboot.org/Mailinglist, where most
libpayload developers are subscribed.


Copyright and License
---------------------

See LICENSES.