coreboot-kgpe-d16/payloads/libpayload
Steven A. Falco 4c514aedd8 port_enable and port_reset must change atomically.
I have observed two separate EHCI host bridges that do not tolerate
using C bit-fields to directly manipulate the portsc_t register.  The
reason for this is that the EHCI spec says that port_enable must go
to 0 at the time that port_reset goes to 1.  Naturally this cannot be
done using direct bit-field manipulation.  Instead, we use a temporary
variable, change the bit-fields there, then atomically write the new
value back to the hardware.

Signed-off-by: Steven A. Falco <sfalco@coincident.com>
Change-Id: If138faee43e0293efa203b86f7893fdf1e811269
Reviewed-on: http://review.coreboot.org/101
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <patrick@georgi-clan.de>
2011-07-17 10:22:23 +02:00
..
arch Fixes to the libpayload build system 2011-07-03 14:47:48 +02:00
bin Add lib/ to the default library path of lpgcc, so -l works 2011-03-01 07:12:08 +00:00
configs Add an EHCI driver to libpayload's USB stack. 2010-09-25 17:01:13 +00:00
crypto Use coreboot build system for libpayload, too. 2011-06-30 20:40:10 +02:00
curses libpayload: Don't declare mouse support in tinycurses 2011-07-07 22:30:05 +02:00
drivers port_enable and port_reset must change atomically. 2011-07-17 10:22:23 +02:00
include libpayload: Improve compatibility 2011-07-16 11:09:28 +02:00
lib
libc libpayload: Add qsort() 2011-07-11 20:23:56 +02:00
libpci Reduce warnings/errors in libpayload when using picky compiler options 2011-06-30 20:41:23 +02:00
sample
util
Config.in Reduce warnings/errors in libpayload when using picky compiler options 2011-06-30 20:41:23 +02:00
Doxyfile
LICENSES
Makefile Fixes to the libpayload build system 2011-07-03 14:47:48 +02:00
Makefile.inc Use coreboot build system for libpayload, too. 2011-06-30 20:40:10 +02:00
README Update repo path in libpayload readme. 2011-03-29 19:29:01 +00:00

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
------------

 $ svn co svn://coreboot.org/coreboot/trunk/payloads/libpayload

 $ cd 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.