[alsa-devel] [PATCH 1/2] ASoC: omap-mcbsp: Use DMA packet mode for non mono streams on OMAP3+

[Peter Ujfalusi]

Take the DMA packet mode into use when the McBSP is configured in element
dma_op_mode if the stream is not mono.
In this way we transfer one sample from/to McBSP FIFO upon DMA request.
This change only affects OMAP3+ versions, where the McBSP ports have FIFO.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi at ti.com>
---
 sound/soc/omap/omap-mcbsp.c |   30 +++++++++++++++++-------------
 1 files changed, 17 insertions(+), 13 deletions(-)

diff --git a/sound/soc/omap/omap-mcbsp.c b/sound/soc/omap/omap-mcbsp.c
index 6912ac7..418dc3c 100644
--- a/sound/soc/omap/omap-mcbsp.c
+++ b/sound/soc/omap/omap-mcbsp.c
@@ -71,18 +71,17 @@ static void omap_mcbsp_set_threshold(struct snd_pcm_substream *substream)
 
 	dma_data = snd_soc_dai_get_dma_data(rtd->cpu_dai, substream);
 
-	/* TODO: Currently, MODE_ELEMENT == MODE_FRAME */
-	if (mcbsp->dma_op_mode == MCBSP_DMA_MODE_THRESHOLD)
-		/*
-		 * Configure McBSP threshold based on either:
-		 * packet_size, when the sDMA is in packet mode, or
-		 * based on the period size.
-		 */
-		if (dma_data->packet_size)
-			words = dma_data->packet_size;
-		else
-			words = snd_pcm_lib_period_bytes(substream) /
-							(mcbsp->wlen / 8);
+	/*
+	 * Configure McBSP threshold based on either:
+	 * packet_size, when the sDMA is in packet mode, or based on the
+	 * period size in THRESHOLD mode, otherwise use McBSP threshold = 1
+	 * for mono streams.
+	 */
+	if (dma_data->packet_size)
+		words = dma_data->packet_size;
+	else if (mcbsp->dma_op_mode == MCBSP_DMA_MODE_THRESHOLD)
+		words = snd_pcm_lib_period_bytes(substream) /
+						(mcbsp->wlen / 8);
 	else
 		words = 1;
 
@@ -230,6 +229,7 @@ static int omap_mcbsp_dai_hw_params(struct snd_pcm_substream *substream,
 	unsigned int format, div, framesize, master;
 
 	dma_data = &mcbsp->dma_data[substream->stream];
+	channels = params_channels(params);
 
 	switch (params_format(params)) {
 	case SNDRV_PCM_FORMAT_S16_LE:
@@ -283,6 +283,10 @@ static int omap_mcbsp_dai_hw_params(struct snd_pcm_substream *substream,
 			} else {
 				sync_mode = OMAP_DMA_SYNC_FRAME;
 			}
+		} else if (channels > 1) {
+			/* Use packet mode for non mono streams */
+			pkt_size = channels;
+			sync_mode = OMAP_DMA_SYNC_PACKET;
 		}
 	}
 
@@ -301,7 +305,7 @@ static int omap_mcbsp_dai_hw_params(struct snd_pcm_substream *substream,
 	regs->rcr1	&= ~(RFRLEN1(0x7f) | RWDLEN1(7));
 	regs->xcr1	&= ~(XFRLEN1(0x7f) | XWDLEN1(7));
 	format = mcbsp->fmt & SND_SOC_DAIFMT_FORMAT_MASK;
-	wpf = channels = params_channels(params);
+	wpf = channels;
 	if (channels == 2 && (format == SND_SOC_DAIFMT_I2S ||
 			      format == SND_SOC_DAIFMT_LEFT_J)) {
 		/* Use dual-phase frames */
-- 
1.7.8.5