i2c: designware: fix RX FIFO overrun
authorJosef Ahmad <josef.ahmad@linux.intel.com>
Fri, 19 Apr 2013 16:28:10 +0000 (17:28 +0100)
committerWolfram Sang <wsa@the-dreams.de>
Fri, 17 May 2013 08:33:11 +0000 (10:33 +0200)
commite6f34cea56f5b95498070eaa9f4aa3ba4a9e4f62
treee3b50a4ea7df97b564811788585759b2ae410dec
parentf722406faae2d073cc1d01063d1123c35425939e
i2c: designware: fix RX FIFO overrun

i2c_dw_xfer_msg() pushes a number of bytes to transmit/receive
to/from the bus into the TX FIFO.
For master-rx transactions, the maximum amount of data that can be
received is calculated depending solely on TX and RX FIFO load.

This is racy - TX FIFO may contain master-rx data yet to be
processed, which will eventually land into the RX FIFO. This
data is not taken into account and the function may request more
data than the controller is actually capable of storing.

This patch ensures the driver takes into account the outstanding
master-rx data in TX FIFO to prevent RX FIFO overrun.

Signed-off-by: Josef Ahmad <josef.ahmad@linux.intel.com>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Cc: stable@kernel.org
drivers/i2c/busses/i2c-designware-core.c
drivers/i2c/busses/i2c-designware-core.h