From 2746e2c389f9d50043d21e2204270403efb9d62f Mon Sep 17 00:00:00 2001 From: Thierry Bultel Date: Mon, 5 Mar 2018 14:27:18 +0100 Subject: 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 Signed-off-by: Vinod Koul --- drivers/dma/imx-sdma.c | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) (limited to 'drivers/dma/imx-sdma.c') diff --git a/drivers/dma/imx-sdma.c b/drivers/dma/imx-sdma.c index e7db24c67030d..ccd03c3cedfed 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; } -- cgit v1.2.3