Julius Werner 4fda9bd0ec libpayload: Replace majority of timer drivers with a generic one
Currently every non-x86 platform supported by libpayload needs to
provide its own timer driver. Most of the ones we have accumulated there
look almost identical: For the frequency, return a preset constant. For
the value, read a 32-bit register, possibly read another 32-bit register
and shift+OR it with the previous one, then return that.

Let's replace this with a single .c file that can easily handle all of
those cases. Menuconfig convenience can still be maintained by providing
several presets that select different defaults for the driver's
configuration options (register address(es) and frequency).

Removes an "enabled" check from Samsung MCT driver since coreboot always
unconditionally enables that timer anyway.

CQ-DEPEND=CL:344809
BRANCH=None
BUG=None
TEST=Booted Oak and Veyron, observed how dev-mode delay was still ~30s

Change-Id: I61cb7d2ffd4902aa841c57f9afa9cd991f770acd
Signed-off-by: Julius Werner <jwerner@chromium.org>
Original-Commit-Id: a036af6
Original-Change-Id: I9784e7c6aa5abd6d92478ea7ec1cf42c9a437546
Original-Signed-off-by: Julius Werner <jwerner@chromium.org>
Original-Reviewed-on: https://chromium-review.googlesource.com/347749
Reviewed-on: https://review.coreboot.org/17023
Tested-by: build bot (Jenkins)
Reviewed-by: Nico Huber <nico.h@gmx.de>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
2016-10-17 22:43:37 +02:00
..
2016-05-09 07:49:57 +02:00
2016-09-08 21:11:34 +02:00
2015-06-08 00:55:07 +02:00
2015-06-08 00:55:07 +02:00
2015-06-08 00:55:07 +02:00
2015-06-08 00:55:07 +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.