hda-dma: refactor xrun handling

Changes behaviour of HDA Link overruns and underruns handling.
Let's no longer stop the stream, but just report an error.
It might happen that just after the release buffer is still
full/not yet empty after the previous run, but it shouldn't
affect the data, since stream has been paused anyway.
Also adds additional bit to better reflect hardware registers.

Signed-off-by: Tomasz Lauda <tomasz.lauda@linux.intel.com>

Author: tlauda

src/drivers/intel/cavs/hda-dma.c

@@ -50,7 +50,9 @@
 #define DGCS_GEN	BIT(26)
 #define DGCS_FWCB	BIT(23)
 #define DGCS_BSC	BIT(11)
-#define DGCS_BOR	BIT(10) /* buffer overrun */
+/* NOTE: both XRUN bits are the same, just direction is different */
+#define DGCS_BOR	BIT(10) /* buffer overrun (input streams) */
+#define DGCS_BUR	BIT(10) /* buffer underrun (output streams) */
 #define DGCS_BF		BIT(9)  /* buffer full */
 #define DGCS_BNE	BIT(8)  /* buffer not empty */
 #define DGCS_FIFORDY	BIT(5)  /* enable FIFO */
@@ -778,19 +780,14 @@ static int hda_dma_remove(struct dma *dma)
 
 static int hda_dma_link_check_xrun(struct dma_chan_data *chan)
 {
-	uint32_t dgcs;
+	uint32_t dgcs = dma_chan_reg_read(chan, DGCS);
 
-	if (chan->direction == DMA_DIR_MEM_TO_DEV ||
-	    chan->direction == DMA_DIR_DEV_TO_MEM) {
-		/* check for link xruns */
-		dgcs = dma_chan_reg_read(chan, DGCS);
-		if (dgcs & DGCS_BOR) {
-			trace_hddma_error("hda_dma_link_check_xrun() error: "
-					  "xrun detected");
-			dma_chan_reg_update_bits(chan, DGCS, DGCS_BOR,
-						 DGCS_BOR);
-			return -ENODATA;
-		}
+	if (chan->direction == DMA_DIR_MEM_TO_DEV && dgcs & DGCS_BUR) {
+		trace_hddma_error("hda_dma_link_check_xrun() error: underrun detected");
+		dma_chan_reg_update_bits(chan, DGCS, DGCS_BUR, DGCS_BUR);
+	} else if (chan->direction == DMA_DIR_DEV_TO_MEM && dgcs & DGCS_BOR) {
+		trace_hddma_error("hda_dma_link_check_xrun() error: overrun detected");
+		dma_chan_reg_update_bits(chan, DGCS, DGCS_BOR, DGCS_BOR);
 	}
 
 	return 0;