Julius Werner 4498f6a6e5 libpayload: usbhub: Don't clear PSC unless it was set
The current USB hub code always clears the port status change after
checking it, regardless of whether it was set in the first place. Since
this check runs on every poll, it might create a race condition where
the port status changes right between the GET_PORT_STATUS and the
CLEAR_FEATURE(C_PORT_CONNECT), thus clearing the statrus change flag
before it was ever read. Let's add one extra if() to avoid that possible
headache.

Change-Id: Idd46c2199dc6c240bd9ef068fbe70cccc88bac42
Signed-off-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/168098
(cherry picked from commit f7f6f008f701ab3e4a4f785032d8024d676e11cb)
Signed-off-by: Isaac Christensen <isaac.christensen@se-eng.com>
Reviewed-on: http://review.coreboot.org/6617
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <patrick@georgi-clan.de>
2014-08-12 23:19:42 +02:00
..
2014-08-10 22:25:07 +02:00
2012-04-04 00:40:31 +02:00
2014-08-09 17:30:33 +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.