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

Barry Song
2015-07-14T00:28:25Z

From: Yanchang Li <yl22@csr.com>

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