1 files changed, 60 insertions, 36 deletions

diff --git a/drivers/dma/mxs-dma.c b/drivers/dma/mxs-dma.c
index 7ab7cecc48a4..1d1b6e99993d 100644
--- a/drivers/dma/mxs-dma.c
+++ b/drivers/dma/mxs-dma.c
@@ -27,6 +27,7 @@
 #include <linux/of.h>
 #include <linux/of_device.h>
 #include <linux/of_dma.h>
+#include <linux/list.h>
 
 #include <asm/irq.h>
 
@@ -272,58 +273,81 @@ static void mxs_dma_tasklet(unsigned long data)
 		mxs_chan->desc.callback(mxs_chan->desc.callback_param);
 }
 
+static int mxs_dma_irq_to_chan(struct mxs_dma_engine *mxs_dma, int irq)
+{
+	int i;
+
+	for (i = 0; i != mxs_dma->nr_channels; ++i)
+		if (mxs_dma->mxs_chans[i].chan_irq == irq)
+			return i;
+
+	return -EINVAL;
+}
+
 static irqreturn_t mxs_dma_int_handler(int irq, void *dev_id)
 {
 	struct mxs_dma_engine *mxs_dma = dev_id;
-	u32 stat1, stat2;
+	struct mxs_dma_chan *mxs_chan;
+	u32 completed;
+	u32 err;
+	int chan = mxs_dma_irq_to_chan(mxs_dma, irq);
+
+	if (chan < 0)
+		return IRQ_NONE;
 
 	/* completion status */
-	stat1 = readl(mxs_dma->base + HW_APBHX_CTRL1);
-	stat1 &= MXS_DMA_CHANNELS_MASK;
-	writel(stat1, mxs_dma->base + HW_APBHX_CTRL1 + STMP_OFFSET_REG_CLR);
+	completed = readl(mxs_dma->base + HW_APBHX_CTRL1);
+	completed = (completed >> chan) & 0x1;
+
+	/* Clear interrupt */
+	writel((1 << chan),
+			mxs_dma->base + HW_APBHX_CTRL1 + STMP_OFFSET_REG_CLR);
 
 	/* error status */
-	stat2 = readl(mxs_dma->base + HW_APBHX_CTRL2);
-	writel(stat2, mxs_dma->base + HW_APBHX_CTRL2 + STMP_OFFSET_REG_CLR);
+	err = readl(mxs_dma->base + HW_APBHX_CTRL2);
+	err &= (1 << (MXS_DMA_CHANNELS + chan)) | (1 << chan);
+
+	/*
+	 * error status bit is in the upper 16 bits, error irq bit in the lower
+	 * 16 bits. We transform it into a simpler error code:
+	 * err: 0x00 = no error, 0x01 = TERMINATION, 0x02 = BUS_ERROR
+	 */
+	err = (err >> (MXS_DMA_CHANNELS + chan)) + (err >> chan);
+
+	/* Clear error irq */
+	writel((1 << chan),
+			mxs_dma->base + HW_APBHX_CTRL2 + STMP_OFFSET_REG_CLR);
 
 	/*
 	 * When both completion and error of termination bits set at the
 	 * same time, we do not take it as an error.  IOW, it only becomes
-	 * an error we need to handle here in case of either it's (1) a bus
-	 * error or (2) a termination error with no completion.
+	 * an error we need to handle here in case of either it's a bus
+	 * error or a termination error with no completion. 0x01 is termination
+	 * error, so we can subtract err & completed to get the real error case.
 	 */
-	stat2 = ((stat2 >> MXS_DMA_CHANNELS) & stat2) | /* (1) */
-		(~(stat2 >> MXS_DMA_CHANNELS) & stat2 & ~stat1); /* (2) */
-
-	/* combine error and completion status for checking */
-	stat1 = (stat2 << MXS_DMA_CHANNELS) | stat1;
-	while (stat1) {
-		int channel = fls(stat1) - 1;
-		struct mxs_dma_chan *mxs_chan =
-			&mxs_dma->mxs_chans[channel % MXS_DMA_CHANNELS];
-
-		if (channel >= MXS_DMA_CHANNELS) {
-			dev_dbg(mxs_dma->dma_device.dev,
-				"%s: error in channel %d\n", __func__,
-				channel - MXS_DMA_CHANNELS);
-			mxs_chan->status = DMA_ERROR;
-			mxs_dma_reset_chan(mxs_chan);
-		} else {
-			if (mxs_chan->flags & MXS_DMA_SG_LOOP)
-				mxs_chan->status = DMA_IN_PROGRESS;
-			else
-				mxs_chan->status = DMA_COMPLETE;
-		}
+	err -= err & completed;
 
-		stat1 &= ~(1 << channel);
+	mxs_chan = &mxs_dma->mxs_chans[chan];
 
-		if (mxs_chan->status == DMA_COMPLETE)
-			dma_cookie_complete(&mxs_chan->desc);
-
-		/* schedule tasklet on this channel */
-		tasklet_schedule(&mxs_chan->tasklet);
+	if (err) {
+		dev_dbg(mxs_dma->dma_device.dev,
+			"%s: error in channel %d\n", __func__,
+			chan);
+		mxs_chan->status = DMA_ERROR;
+		mxs_dma_reset_chan(mxs_chan);
+	} else {
+		if (mxs_chan->flags & MXS_DMA_SG_LOOP)
+			mxs_chan->status = DMA_IN_PROGRESS;
+		else
+			mxs_chan->status = DMA_COMPLETE;
 	}
 
+	if (mxs_chan->status == DMA_COMPLETE)
+		dma_cookie_complete(&mxs_chan->desc);
+
+	/* schedule tasklet on this channel */
+	tasklet_schedule(&mxs_chan->tasklet);
+
 	return IRQ_HANDLED;
 }