dmaengine: pl330: Fix hang on dmaengine_terminate_all on certain boards

commit 81cc6edc08705ac0146fe6ac14a0982a31ce6f3d upstream.

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")
Tested-by: Dinh Nguyen <dinguyen@opensource.altera.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/dma/pl330.c b/drivers/dma/pl330.c
index 0e1f56772855d8fc7f1194099a4c113a6b1c8ddf..a2771a8d43774ccfef418f8a6dc0a68d4fb462aa 100644 (file)
--- a/drivers/dma/pl330.c
+++ b/drivers/dma/pl330.c
@@ -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;
 }