| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.0 046/105] dmaengine: pl330: Fix hang on dmaengine_terminate_all on certain boards | Date | Fri, 19 Jun 2015 13:35:36 -0700 |
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4.0-stable review patch. If anyone has any objections, please let me know.
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From: Krzysztof Kozlowski <k.kozlowski@samsung.com>
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>
--- drivers/dma/pl330.c | 3 +++ 1 file changed, 3 insertions(+)
--- a/drivers/dma/pl330.c +++ b/drivers/dma/pl330.c @@ -2127,6 +2127,7 @@ static int pl330_terminate_all(struct dm 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 dm 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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