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authorThierry Bultel <tbultel@pixelsurmer.com>2018-03-05 16:27:18 +0300
committerVinod Koul <vinod.koul@intel.com>2018-03-05 17:03:47 +0300
commit2746e2c389f9d50043d21e2204270403efb9d62f (patch)
tree3004e9ec5637564c18bb3a8841ae52ba73949ef3 /drivers/dma/imx-sdma.c
parent7928b2cbe55b2a410a0f5c1f154610059c57b1b2 (diff)
downloadlinux-2746e2c389f9d50043d21e2204270403efb9d62f.tar.xz
dmaengine: imx-sdma: fix pagefault when channel is disabled during interrupt
Add a spinlock and a 'enabled' boolean on channel descriptor, to avoid using buffer descriptors in the interrupt context, when sdma_disable_channel is called meanwhile. Signed-off-by: Thierry Bultel <tbultel@pixelsurmer.com> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Diffstat (limited to 'drivers/dma/imx-sdma.c')
-rw-r--r--drivers/dma/imx-sdma.c21
1 files changed, 21 insertions, 0 deletions
diff --git a/drivers/dma/imx-sdma.c b/drivers/dma/imx-sdma.c
index e7db24c67030..ccd03c3cedfe 100644
--- a/drivers/dma/imx-sdma.c
+++ b/drivers/dma/imx-sdma.c
@@ -338,6 +338,7 @@ struct sdma_channel {
unsigned int chn_real_count;
struct tasklet_struct tasklet;
struct imx_dma_data data;
+ bool enabled;
};
#define IMX_DMA_SG_LOOP BIT(0)
@@ -596,7 +597,14 @@ static int sdma_config_ownership(struct sdma_channel *sdmac,
static void sdma_enable_channel(struct sdma_engine *sdma, int channel)
{
+ unsigned long flags;
+ struct sdma_channel *sdmac = &sdma->channel[channel];
+
writel(BIT(channel), sdma->regs + SDMA_H_START);
+
+ spin_lock_irqsave(&sdmac->lock, flags);
+ sdmac->enabled = true;
+ spin_unlock_irqrestore(&sdmac->lock, flags);
}
/*
@@ -685,6 +693,14 @@ static void sdma_update_channel_loop(struct sdma_channel *sdmac)
struct sdma_buffer_descriptor *bd;
int error = 0;
enum dma_status old_status = sdmac->status;
+ unsigned long flags;
+
+ spin_lock_irqsave(&sdmac->lock, flags);
+ if (!sdmac->enabled) {
+ spin_unlock_irqrestore(&sdmac->lock, flags);
+ return;
+ }
+ spin_unlock_irqrestore(&sdmac->lock, flags);
/*
* loop mode. Iterate over descriptors, re-setup them and
@@ -938,10 +954,15 @@ static int sdma_disable_channel(struct dma_chan *chan)
struct sdma_channel *sdmac = to_sdma_chan(chan);
struct sdma_engine *sdma = sdmac->sdma;
int channel = sdmac->channel;
+ unsigned long flags;
writel_relaxed(BIT(channel), sdma->regs + SDMA_H_STATSTOP);
sdmac->status = DMA_ERROR;
+ spin_lock_irqsave(&sdmac->lock, flags);
+ sdmac->enabled = false;
+ spin_unlock_irqrestore(&sdmac->lock, flags);
+
return 0;
}