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 <[email protected]>
Signed-off-by: Krzysztof Kozlowski <[email protected]>
Fixes: ae43b3289186 ("ARM: 8202/1: dmaengine: pl330: Add runtime Power Management support v12")
Cc: <[email protected]>
Cc: Dinh Nguyen <[email protected]>
---
drivers/dma/pl330.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/dma/pl330.c b/drivers/dma/pl330.c
index a7d9d3029b14..340f9e607cd8 100644
--- 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;
}
--
1.9.1
Hi Krzysztof,
On 05/20/2015 07:34 PM, Krzysztof Kozlowski wrote:
> 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 <[email protected]>
> Signed-off-by: Krzysztof Kozlowski <[email protected]>
> Fixes: ae43b3289186 ("ARM: 8202/1: dmaengine: pl330: Add runtime Power Management support v12")
> Cc: <[email protected]>
> Cc: Dinh Nguyen <[email protected]>
> ---
> drivers/dma/pl330.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/drivers/dma/pl330.c b/drivers/dma/pl330.c
> index a7d9d3029b14..340f9e607cd8 100644
> --- 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;
> }
>
This patch indeeds fixes the pl330 DMA issue for the SoCFPGA platform.
The multi_v7_defconfig now completely boots on the platform with this patch.
Feel free to add:
Tested-by: Dinh Nguyen <[email protected]>
Thanks,
Dinh