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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>
This commit is contained in:
Thierry Bultel 2018-03-05 14:27:18 +01:00 committed by Vinod Koul
parent 7928b2cbe5
commit 2746e2c389
1 changed files with 21 additions and 0 deletions
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21
drivers/dma/imx-sdma.c
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@ -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;
}