[PATCH 02/11] ASoC: omap-mcbsp: Use sDMA packet mode instead of frame mode

Peter Ujfalusi
2012-09-12T11:46:51Z

When McBSP is configured in threshold mode we can use sDMA packet mode in
all cases.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
---
sound/soc/omap/omap-mcbsp.c | 47 ++++++++++++++++-----------------------------
1 file changed, 17 insertions(+), 30 deletions(-)

diff --git a/sound/soc/omap/omap-mcbsp.c b/sound/soc/omap/omap-mcbsp.c
index 2e91a86..fe3debc 100644
--- a/sound/soc/omap/omap-mcbsp.c
+++ b/sound/soc/omap/omap-mcbsp.c
@@ -81,9 +81,6 @@ static void omap_mcbsp_set_threshold(struct snd_pcm_substream *substream)
*/
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;

@@ -251,6 +248,7 @@ static int omap_mcbsp_dai_hw_params(struct snd_pcm_substream *substream,
dma_data->set_threshold = omap_mcbsp_set_threshold;
if (mcbsp->dma_op_mode == MCBSP_DMA_MODE_THRESHOLD) {
int period_words, max_thrsh;
+ int divider = 0;

period_words = params_period_bytes(params) / (wlen / 8);
if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
@@ -258,34 +256,23 @@ static int omap_mcbsp_dai_hw_params(struct snd_pcm_substream *substream,
else
max_thrsh = mcbsp->max_rx_thres;
/*
- * If the period contains less or equal number of words,
- * we are using the original threshold mode setup:
- * McBSP threshold = sDMA frame size = period_size
- * Otherwise we switch to sDMA packet mode:
- * McBSP threshold = sDMA packet size
- * sDMA frame size = period size
+ * Use sDMA packet mode if McBSP is in threshold mode:
+ * If period words less than the FIFO size the packet
+ * size is set to the number of period words, otherwise
+ * Look for the biggest threshold value which divides
+ * the period size evenly.
*/
- if (period_words > max_thrsh) {
- int divider = 0;
-
- /*
- * Look for the biggest threshold value, which
- * divides the period size evenly.
- */
- divider = period_words / max_thrsh;
- if (period_words % max_thrsh)
- divider++;
- while (period_words % divider &&
- divider < period_words)
- divider++;
- if (divider == period_words)
- return -EINVAL;
-
- pkt_size = period_words / divider;
- sync_mode = OMAP_DMA_SYNC_PACKET;
- } else {
- sync_mode = OMAP_DMA_SYNC_FRAME;
- }
+ divider = period_words / max_thrsh;
+ if (period_words % max_thrsh)
+ divider++;
+ while (period_words % divider &&
+ divider < period_words)
+ divider++;
+ if (divider == period_words)
+ return -EINVAL;
+
+ pkt_size = period_words / divider;
+ sync_mode = OMAP_DMA_SYNC_PACKET;
} else if (channels > 1) {
/* Use packet mode for non mono streams */
pkt_size = channels;
--
1.7.12