dmaengine: pl330: Fix hang on dmaengine_terminate_all on certain boards
authorKrzysztof Kozlowski <k.kozlowski@samsung.com>
Thu, 21 May 2015 00:34:09 +0000 (09:34 +0900)
committerVinod Koul <vinod.koul@intel.com>
Fri, 22 May 2015 12:31:03 +0000 (18:01 +0530)
commit81cc6edc08705ac0146fe6ac14a0982a31ce6f3d
treea2f9eba6363f198527f5553aef5ed72a005c10fc
parent5ebe6afaf0057ac3eaeb98defd5456894b446d22
dmaengine: pl330: Fix hang on dmaengine_terminate_all on certain boards

The pl330 device could hang infinitely on certain boards when DMA
channels are terminated.

It was caused by lack of runtime resume when executing
pl330_terminate_all() which calls the _stop() function. _stop() accesses
device register and can loop infinitely while checking for device state.

The hang was confirmed by Dinh Nguyen on Altera SOCFPGA Cyclone V
board during boot. It can be also triggered with:

$ echo 1 > /sys/module/dmatest/parameters/iterations
$ echo dma1chan0 > /sys/module/dmatest/parameters/channel
$ echo 1 > /sys/module/dmatest/parameters/run
$ sleep 1
$ cat /sys/module/dmatest/parameters/run

Reported-by: Dinh Nguyen <dinguyen@opensource.altera.com>
Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Fixes: ae43b3289186 ("ARM: 8202/1: dmaengine: pl330: Add runtime Power Management support v12")
Cc: <stable@vger.kernel.org>
Tested-by: Dinh Nguyen <dinguyen@opensource.altera.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
drivers/dma/pl330.c