Commit 81cc6edc authored May 21, 2015 by Krzysztof Kozlowski Committed by Vinod Koul May 22, 2015

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: ae43b328 ("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>

parent 5ebe6afa

drivers/dma/pl330.c

+3 −0

Original line number	Diff line number	Diff line
		@@ -2127,6 +2127,7 @@ static int pl330_terminate_all(struct dma_chan *chan)
		struct pl330_dmac *pl330 = pch->dmac;
		LIST_HEAD(list);

		pm_runtime_get_sync(pl330->ddma.dev);
		spin_lock_irqsave(&pch->lock, flags);
		spin_lock(&pl330->lock);
		_stop(pch->thread);
		@@ -2151,6 +2152,8 @@ static int pl330_terminate_all(struct dma_chan *chan)
		list_splice_tail_init(&pch->work_list, &pl330->desc_pool);
		list_splice_tail_init(&pch->completed_list, &pl330->desc_pool);
		spin_unlock_irqrestore(&pch->lock, flags);
		pm_runtime_mark_last_busy(pl330->ddma.dev);
		pm_runtime_put_autosuspend(pl330->ddma.dev);

		return 0;
		}

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