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Commit 2746e2c3 authored by Thierry Bultel's avatar Thierry Bultel Committed by Vinod Koul
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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: default avatarThierry Bultel <tbultel@pixelsurmer.com>
Signed-off-by: default avatarVinod Koul <vinod.koul@intel.com>
parent 7928b2cb

drivers/dma/imx-sdma.c

+21 −0
Original line number Diff line number Diff line
@@ -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;

}