coreboot-kgpe-d16/payloads/libpayload
Julius Werner 69eea7c01a libpayload: Split EHCI bulk transfers on packet boundaries over qTDs
EHCI controllers see transfers as a queue of transfer descriptors
(qTDs), each of which can represent an aligned area of up to 20KB. Each
qTD is processed separately, which means that a single USB packet cannot
span multiple qTDs.

While this should not be a problem according to the specification, some
USB storage devices seem to get confused when a packet in the middle of
a transfer is smaller than the maximum packet size (512 bytes) due to
falling on a qTD boundary. This patch aligns the total transfer length
per qTD to 512 bytes to avoid that problem (any excess bytes will simply
roll over to the next qTD).

Change-Id: I0b5db07507699a3861b30c1a5ee774c45dda7fdd
Signed-off-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: http://review.coreboot.org/2651
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <patrick@georgi-clan.de>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>
2013-03-13 23:08:11 +01:00
..
arch libpayload: Make whether or not there's an IO address space configurable 2013-03-13 23:02:05 +01:00
bin libpayload: fix compiler flags 2013-02-15 06:51:52 +01:00
configs libpayload: Update configs/defconfig file 2012-12-18 15:05:36 +01:00
crypto Change TARGET_I386 to ARCH_X86 2012-11-30 23:20:54 +01:00
curses PDcurses: Delete automatically created (and unused) files 2012-12-20 14:46:29 +01:00
drivers libpayload: Split EHCI bulk transfers on packet boundaries over qTDs 2013-03-13 23:08:11 +01:00
include libpayload: Start using only internal and compiler headers. 2013-03-13 22:04:44 +01:00
libc libpayload: Stub out time keeping functions for ARM as well 2013-03-13 23:06:27 +01:00
libcbfs libpayload: Fix reading x86 CBFS images from RAM 2013-03-12 10:23:12 +01:00
liblzma libpayload: Make the source for lzma decompression const 2013-03-13 18:16:35 +01:00
libpci libpayload: minor cleanups 2012-04-04 00:40:31 +02:00
sample fix compilation of hello.elf example payload. 2010-08-28 23:23:47 +00:00
util libpayload: Start using only internal and compiler headers. 2013-03-13 22:04:44 +01:00
Config.in libpayload: Make whether or not there's an IO address space configurable 2013-03-13 23:02:05 +01:00
Doxyfile Run doxygen -u on doxygen configuration files 2010-06-28 10:40:38 +00:00
LICENSES Since some people disapprove of white space cleanups mixed in regular commits 2010-04-27 06:56:47 +00:00
Makefile libpayload: Initial ARMv7 port 2012-12-14 22:29:48 +01:00
Makefile.inc libpayload: Start using only internal and compiler headers. 2013-03-13 22:04:44 +01:00
README libpayload: Update README with Git repository URL and directory location 2013-01-30 17:36:22 +01:00

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 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.