[PATCH] ASoC: MPC5200: Support for buffer wrap around

[John Bonesio]

The code in psc_dma_bcom_enqueue_tx() didn't account for the fact that
s->runtime->control->appl_ptr can wrap around to the beginning of the
buffer. This change fixes this problem.

Signed-off-by: John Bonesio <bones at secretlab.ca>
---
 sound/soc/fsl/mpc5200_dma.c |   17 +++++++++++++++++
 1 files changed, 17 insertions(+), 0 deletions(-)

diff --git a/sound/soc/fsl/mpc5200_dma.c b/sound/soc/fsl/mpc5200_dma.c
index cfe0ea4..2551c58 100644
--- a/sound/soc/fsl/mpc5200_dma.c
+++ b/sound/soc/fsl/mpc5200_dma.c
@@ -70,6 +70,23 @@ static void psc_dma_bcom_enqueue_next_buffer(struct psc_dma_stream *s)
 
 static void psc_dma_bcom_enqueue_tx(struct psc_dma_stream *s)
 {
+	if (s->appl_ptr > s->runtime->control->appl_ptr) {
+		/*
+		 * In this case s->runtime->control->appl_ptr has wrapped around.
+		 * Play the data to the end of the boundary, then wrap our own
+		 * appl_ptr back around.
+		 */
+		while (s->appl_ptr < s->runtime->boundary) {
+			if (bcom_queue_full(s->bcom_task))
+				return;
+
+			s->appl_ptr += s->period_size;
+
+			psc_dma_bcom_enqueue_next_buffer(s);
+		}
+		s->appl_ptr -= s->runtime->boundary;
+	}
+
 	while (s->appl_ptr < s->runtime->control->appl_ptr) {
 
 		if (bcom_queue_full(s->bcom_task))
-- 
1.6.0.4


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