Commit ddc29b01 authored by Peter Ujfalusi's avatar Peter Ujfalusi Committed by Liam Girdwood
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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: default avatarPeter Ujfalusi <peter.ujfalusi@nokia.com>
Acked-by: default avatarJarkko Nikula <jhnikula@gmail.com>
Acked-by: default avatarMark Brown <broonie@opensource.wolsfonmicro.com>
Acked-by: default avatarTony Lindgren <tony@atomide.com>
Signed-off-by: default avatarLiam Girdwood <lrg@slimlogic.co.uk>
parent 3f024039

sound/soc/omap/omap-mcbsp.c

+77 −21
Original line number Diff line number Diff line
@@ -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

		*/

		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;

		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 (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;

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