coreboot-kgpe-d16/payloads/libpayload
Vadim Bendebury 6cc5e52ec6 libpayload: read register width from coreboot table
Some SOCs (like pistachio, for instance) provide an 8250 compatible
UART, which has the same register layout, but mapped to a bus of a
different width.

Instead of adding a new driver for these controllers, it is better to
have coreboot report UART register width to libpayload, and have it
adjust the offsets accordingly when accessing the UART.

BRANCH=none
BUG=chrome-os-partner:31438
TEST=with the rest of the patches integrated depthcharge console messages
     show up when running on the FPGA board

Change-Id: I05891a9471a5369d3bfafe90cd0c9b0a7e5a667e
Signed-off-by: Patrick Georgi <pgeorgi@chromium.org>
Original-Commit-Id: 2c30845f269ec6ae1d53ddc5cda0b4320008fa42
Original-Change-Id: Ia0a37cd5f24a1ee4d0334f8a7e3da5df0069cec4
Original-Signed-off-by: Vadim Bendebury <vbendeb@chromium.org>
Original-Reviewed-on: https://chromium-review.googlesource.com/240027
Original-Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/9739
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
2015-04-17 09:53:54 +02:00
..
arch libpayload: sync arch/arm/cache.c with coreboot 2015-04-17 09:27:42 +02:00
bin libpayload: arch/mips: Add basic MIPS architecture support 2015-03-21 11:07:50 +01:00
configs Danger: Initial mainboard import 2015-04-15 16:48:48 +02:00
crypto libpayload: Change CONFIG_* to CONFIG_LP_* in the kconfig. 2014-08-05 18:44:08 +02:00
curses libpayload/PDcurses: avoid NULL deref 2015-01-03 23:58:22 +01:00
drivers libpayload: read register width from coreboot table 2015-04-17 09:53:54 +02:00
gdb libpayload: Let GDB stub read/write memory with aligned MMIO words 2015-01-12 05:56:16 +01:00
include libpayload: read register width from coreboot table 2015-04-17 09:53:54 +02:00
libc libpayload: Take flash parameters from coreboot 2015-04-17 09:21:12 +02:00
libcbfs CBFS: Automate ROM image layout and remove hardcoded offsets 2015-04-14 09:01:27 +02:00
liblzma LZMA: Add a version of ulzma which takes the input and output buffer sizes. 2014-08-10 22:29:51 +02:00
libpci libpayload: minor cleanups 2012-04-04 00:40:31 +02:00
sample libpayload: Fix missed CONFIG_ -> CONFIG_LP_ substitutions 2014-10-17 11:24:15 +02:00
tests libpayload: Change CONFIG_X86_SERIAL_CONSOLE to CONFIG_8250_SERIAL_CONSOLE 2014-08-28 01:40:48 +02:00
util libpayload: arch/mips: Add basic MIPS architecture support 2015-03-21 11:07:50 +01:00
Config.in libpayload: Add dwc2 usb driver 2015-04-14 10:42:54 +02:00
Doxyfile Run doxygen -u on doxygen configuration files 2010-06-28 10:40:38 +00:00
LICENSES libpayload: Introduce new Kconfig to explicitly allow GPL code 2015-01-09 07:06:27 +01:00
LICENSE_GPL libpayload: Introduce new Kconfig to explicitly allow GPL code 2015-01-09 07:06:27 +01:00
Makefile libpayload: arch/mips: Add basic MIPS architecture support 2015-03-21 11:07:50 +01:00
Makefile.inc libpayload: avoid hanging on make junit.xml 2015-04-14 16:39:42 +02:00
README libpayload, superiotool: README: Prepend `coreboot/` to path of change directory line 2013-04-04 17:22:15 +02:00

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.