On Mon, 2010-05-31 at 11:16 +0300, Peter Ujfalusi wrote:
OMAP McBSP FIFO is word structured: McBSP2 has 1024 + 256 = 1280 word long buffer, McBSP1,3,4,5 has 128 word long buffer
This means, that the size of the FIFO depends on the McBSP word size configuration. For example on McBSP3: 16bit samples: size is 128 * 2 = 256 bytes 32bit samples: size is 128 * 4 = 512 bytes It is simpler to place constraint for buffer and period based on channels. McBSP3 as example again (16 or 32 bit samples): 1 channel (mono): size is 128 frames (128 words) 2 channels (stereo): size is 128 / 2 = 64 frames (2 * 64 words) 4 channels: size is 128 / 4 = 32 frames (4 * 32 words)
Use the second method to place hw_rule on buffer size, and in threshold mode to period size.
Signed-off-by: Peter Ujfalusi peter.ujfalusi@nokia.com
sound/soc/omap/omap-mcbsp.c | 98 +++++++++++++++++++++++++++++++++--------- 1 files changed, 77 insertions(+), 21 deletions(-)
diff --git a/sound/soc/omap/omap-mcbsp.c b/sound/soc/omap/omap-mcbsp.c index b06d8f1..d6ed761 100644 --- a/sound/soc/omap/omap-mcbsp.c +++ b/sound/soc/omap/omap-mcbsp.c @@ -173,6 +173,52 @@ static void omap_mcbsp_set_threshold(struct snd_pcm_substream *substream) omap_mcbsp_set_rx_threshold(mcbsp_data->bus_id, words); }
+static int hw_rule_bsize_by_channels(struct snd_pcm_hw_params *params,
struct snd_pcm_hw_rule *rule)+{
- struct snd_interval *bs = hw_param_interval(params,
SNDRV_PCM_HW_PARAM_BUFFER_SIZE);- struct snd_interval *c = hw_param_interval(params,
SNDRV_PCM_HW_PARAM_CHANNELS);
Best to make these variable names more meaningful.
- struct omap_mcbsp_data *mcbsp_data = rule->private;
- struct snd_interval frames;
- int size;
- snd_interval_any(&frames);
- size = omap_mcbsp_get_fifo_size(mcbsp_data->bus_id);
- frames.min = size / c->min;
- frames.integer = 1;
- return snd_interval_refine(bs, &frames);
+}
+static int hw_rule_psize_by_channels(struct snd_pcm_hw_params *params,
struct snd_pcm_hw_rule *rule)+{
- struct snd_interval *ps = hw_param_interval(params,
SNDRV_PCM_HW_PARAM_PERIOD_SIZE);- struct snd_interval *c = hw_param_interval(params,
SNDRV_PCM_HW_PARAM_CHANNELS);
ditto
- struct snd_pcm_substream *substream = rule->private;
- struct snd_soc_pcm_runtime *rtd = substream->private_data;
- struct snd_soc_dai *cpu_dai = rtd->dai->cpu_dai;
- struct omap_mcbsp_data *mcbsp_data = to_mcbsp(cpu_dai->private_data);
- struct snd_interval frames;
- int size;
- snd_interval_any(&frames);
- if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
size = omap_mcbsp_get_max_tx_threshold(mcbsp_data->bus_id);- else
size = omap_mcbsp_get_max_rx_threshold(mcbsp_data->bus_id);- frames.min = 8;
- frames.max = size / c->min;
- frames.integer = 1;
- return snd_interval_refine(ps, &frames);
+}
Thanks
Liam