On Monday 31 May 2010 11:03:26 Ujfalusi Peter (Nokia-D/Tampere) 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 former method to place hw_rule on buffer size, and in threshold mode to period size.
I meant later (second) method ;)
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);- 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);- 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);
+}
static int omap_mcbsp_dai_startup(struct snd_pcm_substream *substream, struct snd_soc_dai *dai) { @@ -185,33 +231,43 @@ static int omap_mcbsp_dai_startup(struct snd_pcm_substream *substream, if (!cpu_dai->active) err = omap_mcbsp_request(bus_id);
- /*
* 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 sample format.* 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)*/- /*
* The first rule is for the buffer size, we should not allow smaller* buffer than the FIFO size to avoid underruns*/- snd_pcm_hw_rule_add(substream->runtime, 0, SNDRV_PCM_HW_PARAM_CHANNELS,
hw_rule_bsize_by_channels, mcbsp_data,SNDRV_PCM_HW_PARAM_BUFFER_SIZE, -1);- if (cpu_is_omap343x()) { int dma_op_mode = omap_mcbsp_get_dma_op_mode(bus_id);
int max_period;/*
* McBSP2 in OMAP3 has 1024 * 32-bit internal audio buffer.* Set constraint for minimum buffer size to the same than FIFO* size in order to avoid underruns in playback startup because* HW is keeping the DMA request active until FIFO is filled.
* In case os threshold mode, the rule will ensure, that the* period size is not bigger than the maximum allowed threshold* value.
if (bus_id == 1)snd_pcm_hw_constraint_minmax(substream->runtime,SNDRV_PCM_HW_PARAM_BUFFER_BYTES,4096, UINT_MAX);if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)max_period = omap_mcbsp_get_max_tx_threshold(bus_id);elsemax_period = omap_mcbsp_get_max_rx_threshold(bus_id);max_period++;max_period <<= 1;- if (dma_op_mode == MCBSP_DMA_MODE_THRESHOLD)
snd_pcm_hw_constraint_minmax(substream->runtime,SNDRV_PCM_HW_PARAM_PERIOD_BYTES,32, max_period);
snd_pcm_hw_rule_add(substream->runtime, 0,SNDRV_PCM_HW_PARAM_CHANNELS,hw_rule_psize_by_channels, substream,SNDRV_PCM_HW_PARAM_PERIOD_SIZE, -1);}
return err;