Files
system76-coreboot/payloads/libpayload
Dan Ehrenberg 6addd40268 libpayload: Take flash parameters from coreboot
A payload may want to run erase operations on SPI NOR flash without
re-probing the device to get its properties. This patch passes up
three properties of flash to achieve that:
- The size of the flash device
- The sector size, i.e., the granularity of erase
- The command used for erase
The patch sends the parameters through coreboot and then libpayload.
The patch also includes a minor refactoring of the flash erase code.
Parameters are sent up for just one flash device. If multiple SPI
flash devices are probed, the second one will "win" and its
parameters will be sent up to the payload.

TEST=Observed parameters to be passed up to depthcharge through
libpayload and be used to correctly initialize flash and do an erase.
TEST=Winbond and Gigadevices spi flash drivers compile with the changes;
others don't, for seemingly unrelated reasons.
BRANCH=none
BUG=chromium:446377

Change-Id: I92b7ff0ce66af8d096ec09a4c900829ef6c867e0
Signed-off-by: Patrick Georgi <pgeorgi@chromium.org>
Original-Commit-Id: 988c8c68bbfcdfa69d497ea5f806567bc80f8126
Original-Change-Id: Ie2b3a7f5b6e016d212f4f9bac3fabd80daf2ce72
Original-Signed-off-by: Dan Ehrenberg <dehrenberg@chromium.org>
Original-Reviewed-on: https://chromium-review.googlesource.com/239570
Original-Reviewed-by: Vadim Bendebury <vbendeb@chromium.org>
Reviewed-on: http://review.coreboot.org/9727
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
2015-04-17 09:21:12 +02:00
..
2015-04-15 16:48:48 +02:00
2012-04-04 00:40:31 +02:00
2015-04-14 10:42:54 +02:00

-------------------------------------------------------------------------------
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.