Julius Werner 49ba283390 libpayload: xhci: Ensure to reset dequeue pointer on stopped endpoints
This patch fixes a bug in the XHCI stack that occurs when a multi-TRB TD
times out before the last TRB is processed. The driver will correctly
issue a Stop Endpoint command in that case, but the xHC will still
preserve the transfer state and just pick up right after that on the
next doorbell ring. It will then process the leftover TRBs from the old
TD the next time a transfer is issued. (cf. XHCI 4.6.9)

We fix this by changing the existing xhci_reset_endpoint() calls in
transfer functions to not only trigger on Halted (2) and Error (4), but
also on Stopped (3). That function will not actually issue a Reset
Endpoint command in this case, but it will nuke the whole transfer ring
and issue a Set TR Dequeue Pointer command, which is sufficient (though
slightly overkill) to solve our problem.

Change-Id: I3abbe30ff9d4911a8af1f792324e018d427019e8
Signed-off-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/170833
Reviewed-by: Ronald Minnich <rminnich@chromium.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
(cherry picked from commit f12424af0e29ac12963e8e5a7970fadcc0bb6cee)
Signed-off-by: Isaac Christensen <isaac.christensen@se-eng.com>
Reviewed-on: http://review.coreboot.org/6787
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
Tested-by: build bot (Jenkins)
2014-08-31 23:49:54 +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.