[PATCH] dmaengine: sirf: fix kernel panic under one race condition

Barry Song
2015-07-20T14:46:36Z

2015-07-16 21:17 GMT+08:00 Vinod Koul <vinod.koul@intel.com>:
> On Tue, Jul 14, 2015 at 12:28:25AM +0000, Barry Song wrote:
>> From: Yanchang Li <yl22@csr.com>
>
> patch title should alos say what is changed. "panic under one race" is not
> an apt description for this
>
> Can you fix that up, otherwise it looks okay
>

yes. it seems it can be

dmaengine: sirf: clear any pending DMA interrupt when DMA terminates

> --
> ~Vinod
>
>>
>> If DMA interrupt comes and is latched by IRQ controller during the
>> execution of dma_terminate_all(), dma_irq routine will be executed
>> after dma terminated, and it will cause kernel panic.
>> We clear DMA interrupts in dma_terminate_all() to avoid this useless
>> interrupt.
>>
>> Signed-off-by: Yanchang Li <yl22@csr.com>
>> Signed-off-by: Barry Song <Baohua.Song@csr.com>
>> ---
>> drivers/dma/sirf-dma.c | 3 +++
>> 1 file changed, 3 insertions(+)
>>
>> diff --git a/drivers/dma/sirf-dma.c b/drivers/dma/sirf-dma.c
>> index 8c5186c..7d5598d 100644
>> --- a/drivers/dma/sirf-dma.c
>> +++ b/drivers/dma/sirf-dma.c
>> @@ -455,6 +455,7 @@ static int sirfsoc_dma_terminate_all(struct dma_chan *chan)
>> switch (sdma->type) {
>> case SIRFSOC_DMA_VER_A7V1:
>> writel_relaxed(1 << cid, sdma->base + SIRFSOC_DMA_INT_EN_CLR);
>> + writel_relaxed(1 << cid, sdma->base + SIRFSOC_DMA_CH_INT);
>> writel_relaxed((1 << cid) | 1 << (cid + 16),
>> sdma->base +
>> SIRFSOC_DMA_CH_LOOP_CTRL_CLR_ATLAS7);
>> @@ -462,6 +463,8 @@ static int sirfsoc_dma_terminate_all(struct dma_chan *chan)
>> break;
>> case SIRFSOC_DMA_VER_A7V2:
>> writel_relaxed(0, sdma->base + SIRFSOC_DMA_INT_EN_ATLAS7);
>> + writel_relaxed(SIRFSOC_DMA_INT_ALL_ATLAS7,
>> + sdma->base + SIRFSOC_DMA_INT_ATLAS7);
>> writel_relaxed(0, sdma->base + SIRFSOC_DMA_LOOP_CTRL_ATLAS7);
>> writel_relaxed(0, sdma->base + SIRFSOC_DMA_VALID_ATLAS7);
>> break;
>> --
>> 2.3.5
>>
>
-barry