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ASoC: omap-mcbsp: Place correct constraints for streams 

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>
Acked-by: Jarkko Nikula <jhnikula@gmail.com>
Acked-by: Mark Brown <broonie@opensource.wolsfonmicro.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>
This commit is contained in:
Peter Ujfalusi 2010-06-03 07:39:36 +03:00 committed by Liam Girdwood
parent 3f024039e0
commit ddc29b0104
1 changed files with 77 additions and 21 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

98
sound/soc/omap/omap-mcbsp.c
View File

@ -173,6 +173,50 @@ static void omap_mcbsp_set_threshold(struct snd_pcm_substream *substream)
omap_mcbsp_set_rx_threshold(mcbsp_data->bus_id, words);
}
static int omap_mcbsp_hwrule_min_buffersize(struct snd_pcm_hw_params *params,
struct snd_pcm_hw_rule *rule)
{
struct snd_interval *buffer_size = hw_param_interval(params,
SNDRV_PCM_HW_PARAM_BUFFER_SIZE);
struct snd_interval *channels = 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 / channels->min;
frames.integer = 1;
return snd_interval_refine(buffer_size, &frames);
}
static int omap_mcbsp_hwrule_max_periodsize(struct snd_pcm_hw_params *params,
struct snd_pcm_hw_rule *rule)
{
struct snd_interval *period_size = hw_param_interval(params,
SNDRV_PCM_HW_PARAM_PERIOD_SIZE);
struct snd_interval *channels = 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.max = size / channels->min;
frames.integer = 1;
return snd_interval_refine(period_size, &frames);
}
static int omap_mcbsp_dai_startup(struct snd_pcm_substream *substream,
struct snd_soc_dai *dai)
{
@ -185,33 +229,45 @@ static int omap_mcbsp_dai_startup(struct snd_pcm_substream *substream,
if (!cpu_dai->active)
err = omap_mcbsp_request(bus_id);
/*
* OMAP3 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)
*/
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.
* 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,
omap_mcbsp_hwrule_min_buffersize,
mcbsp_data,
SNDRV_PCM_HW_PARAM_BUFFER_SIZE, -1);
/*
* In case of 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);
else
max_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,
omap_mcbsp_hwrule_max_periodsize,
substream,
SNDRV_PCM_HW_PARAM_PERIOD_SIZE, -1);
}
return err;