[Sound-open-firmware] [PATCH v3 23/27] dai: add R/W pointer check for dai copy

[Keyon Jie]

We should only copy when there is data, after copied the last bytes
or period, we will stop the dai and ssp, and trigger the pipeline
finish, which will notify host side the last read pointer and let
host side send trigger stop ipc.

Signed-off-by: Keyon Jie <yang.jie at linux.intel.com>
---
 src/audio/dai.c | 47 ++++++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 42 insertions(+), 5 deletions(-)

diff --git a/src/audio/dai.c b/src/audio/dai.c
index 3b2ea30..186532f 100644
--- a/src/audio/dai.c
+++ b/src/audio/dai.c
@@ -69,6 +69,7 @@ struct dai_data {
 	volatile uint64_t *dai_pos; /* host can read back this value without IPC */
 };
 
+static int dai_cmd(struct comp_dev *dev, int cmd, void *data);
 /* this is called by DMA driver every time descriptor has completed */
 static void dai_dma_cb(void *data, uint32_t type, struct dma_sg_elem *next)
 {
@@ -76,17 +77,22 @@ static void dai_dma_cb(void *data, uint32_t type, struct dma_sg_elem *next)
 	struct dai_data *dd = comp_get_drvdata(dev);
 	struct period_desc *dma_period_desc;
 	struct comp_buffer *dma_buffer;
+	uint32_t copied_size;
 
 	if (dd->direction == STREAM_DIRECTION_PLAYBACK) {
 		dma_buffer = list_first_item(&dev->bsource_list,
 			struct comp_buffer, sink_list);
 
 		dma_period_desc = &dma_buffer->desc.sink_period;
-		dma_buffer->r_ptr += dma_period_desc->size;
+		copied_size = dd->last_bytes ? dd->last_bytes : dma_period_desc->size;
+		dma_buffer->r_ptr += copied_size;
 
 		/* check for end of buffer */
-		if (dma_buffer->r_ptr >= dma_buffer->end_addr)
+		if (dma_buffer->r_ptr >= dma_buffer->end_addr) {
 			dma_buffer->r_ptr = dma_buffer->addr;
+			/* update host position(in bytes offset) for drivers */
+			dd->dai_pos_blks += dma_buffer->desc.size;
+		}
 
 #if 0
 		// TODO: move this to new trace mechanism
@@ -109,16 +115,17 @@ static void dai_dma_cb(void *data, uint32_t type, struct dma_sg_elem *next)
 		dma_buffer->w_ptr += dma_period_desc->size;
 
 		/* check for end of buffer */
-		if (dma_buffer->w_ptr >= dma_buffer->end_addr)
+		if (dma_buffer->w_ptr >= dma_buffer->end_addr) {
 			dma_buffer->w_ptr = dma_buffer->addr;
+			/* update host position(in bytes offset) for drivers */
+			dd->dai_pos_blks += dma_buffer->desc.size;
+		}
 
 #if 0
 		// TODO: move this to new trace mechanism
 		trace_value((uint32_t)(dma_buffer->w_ptr - dma_buffer->addr));
 #endif
 
-		/* update host position(in bytes offset) for drivers */
-		dd->dai_pos_blks += dma_period_desc->size;
 		if (dd->dai_pos)
 			*dd->dai_pos = dd->dai_pos_blks +
 				dma_buffer->w_ptr - dma_buffer->addr;
@@ -127,9 +134,39 @@ static void dai_dma_cb(void *data, uint32_t type, struct dma_sg_elem *next)
 		comp_update_buffer_produce(dma_buffer);
 	}
 
+	if (dd->direction == STREAM_DIRECTION_PLAYBACK &&
+				dma_buffer->avail < dma_period_desc->size) {
+		/* end of stream, finish */
+		if (dma_buffer->avail == 0) {
+			dai_cmd(dev, COMP_CMD_STOP, NULL);
+
+			/* stop dma immediatly */
+			next->size = 0;
+
+			/* let any waiters know we have completed */
+			wait_completed(&dev->pipeline->complete);
+
+			return;
+		} else {
+			/* drain the last bytes */
+			next->src = (uint32_t)dma_buffer->r_ptr;
+			next->dest = dai_fifo(dd->ssp, dd->direction);
+			next->size = dma_buffer->avail;
+
+			dd->last_bytes = next->size;
+
+			goto next_copy;
+
+		}
+
+	}
 	/* notify pipeline that DAI needs it's buffer filled */
 //	if (dev->state == COMP_STATE_RUNNING)
 		pipeline_schedule_copy(dev->pipeline, dev);
+
+next_copy:
+
+	return;
 }
 
 static struct comp_dev *dai_new_ssp(uint32_t type, uint32_t index,
-- 
2.7.4