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Subject[PATCH 05/11] ASoC: omap-pcm: Prepare to configure the DMA data_type based on stream properties
Date
Based on the format of the stream the omap-pcm can decide alone what data
type should be used with by the sDMA.
Keep the possibility for OMAP dai drivers to tell omap-pcm if they want to
use different data type. This is needed for the omap-hdmi for example which
needs 32bit data type even if the stream format is S16_LE.

The check if (dma_data->data_type) is safe at the moment since omap-pcm
does not support 8bit samples (OMAP_DMA_DATA_TYPE_S8 == 0x00).

The next step is to redefine the meaning of dma_data->data_type to unblock
this limitation.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
---
sound/soc/omap/omap-pcm.c | 31 +++++++++++++++++++++++++++++--
1 file changed, 29 insertions(+), 2 deletions(-)

diff --git a/sound/soc/omap/omap-pcm.c b/sound/soc/omap/omap-pcm.c
index 02eeb2e..4c13a5f 100644
--- a/sound/soc/omap/omap-pcm.c
+++ b/sound/soc/omap/omap-pcm.c
@@ -149,6 +149,24 @@ static int omap_pcm_hw_free(struct snd_pcm_substream *substream)
return 0;
}

+static int omap_pcm_get_dma_type(int num_bits)
+{
+ int data_type;
+
+ switch (num_bits) {
+ case 16:
+ data_type = OMAP_DMA_DATA_TYPE_S16;
+ break;
+ case 32:
+ data_type = OMAP_DMA_DATA_TYPE_S32;
+ break;
+ default:
+ data_type = -EINVAL;
+ break;
+ }
+ return data_type;
+}
+
static int omap_pcm_prepare(struct snd_pcm_substream *substream)
{
struct snd_pcm_runtime *runtime = substream->runtime;
@@ -163,7 +181,16 @@ static int omap_pcm_prepare(struct snd_pcm_substream *substream)
return 0;

memset(&dma_params, 0, sizeof(dma_params));
- dma_params.data_type = dma_data->data_type;
+
+ if (dma_data->data_type)
+ dma_params.data_type = dma_data->data_type;
+ else
+ dma_params.data_type = omap_pcm_get_dma_type(
+ snd_pcm_format_physical_width(runtime->format));
+
+ if (dma_params.data_type < 0)
+ return dma_params.data_type;
+
dma_params.trigger = dma_data->dma_req;

if (dma_data->packet_size)
@@ -195,7 +222,7 @@ static int omap_pcm_prepare(struct snd_pcm_substream *substream)
* still can get an interrupt at each period bounary
*/
bytes = snd_pcm_lib_period_bytes(substream);
- dma_params.elem_count = bytes >> dma_data->data_type;
+ dma_params.elem_count = bytes >> dma_params.data_type;
dma_params.frame_count = runtime->periods;
omap_set_dma_params(prtd->dma_ch, &dma_params);

--
1.7.12


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