ALSA: fireface: share PCM buffer size for both direction

This commit allows ALSA fireface driver to share PCM buffer size for
both capture and playback PCM substream. When AMDTP domain starts for
one of the PCM substream, buffer size of the PCM substream is stores to
AMDTP domain structure. Some AMDTP streams have already run with the
buffer size when another PCM substream starts, therefore the PCM
substream has a constraint to its buffer size.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20191017155424.885-10-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/firewire/fireface/ff-pcm.c

@@ -180,6 +180,7 @@ static int pcm_open(struct snd_pcm_substream *substream)
 	} else {
 		if (ff->substreams_counter > 0) {
 			unsigned int frames_per_period = d->events_per_period;
+			unsigned int frames_per_buffer = d->events_per_buffer;
 
 			rate = amdtp_rate_table[ff->rx_stream.sfc];
 			substream->runtime->hw.rate_min = rate;
@@ -192,6 +193,14 @@ static int pcm_open(struct snd_pcm_substream *substream)
 				mutex_unlock(&ff->mutex);
 				goto release_lock;
 			}
+
+			err = snd_pcm_hw_constraint_minmax(substream->runtime,
+					SNDRV_PCM_HW_PARAM_BUFFER_SIZE,
+					frames_per_buffer, frames_per_buffer);
+			if (err < 0) {
+				mutex_unlock(&ff->mutex);
+				goto release_lock;
+			}
 		}
 	}
 
@@ -229,9 +238,11 @@ static int pcm_hw_params(struct snd_pcm_substream *substream,
 	if (substream->runtime->status->state == SNDRV_PCM_STATE_OPEN) {
 		unsigned int rate = params_rate(hw_params);
 		unsigned int frames_per_period = params_period_size(hw_params);
+		unsigned int frames_per_buffer = params_buffer_size(hw_params);
 
 		mutex_lock(&ff->mutex);
-		err = snd_ff_stream_reserve_duplex(ff, rate, frames_per_period);
+		err = snd_ff_stream_reserve_duplex(ff, rate, frames_per_period,
+						   frames_per_buffer);
 		if (err >= 0)
 			++ff->substreams_counter;
 		mutex_unlock(&ff->mutex);

sound/firewire/fireface/ff-stream.c

@@ -107,7 +107,8 @@ void snd_ff_stream_destroy_duplex(struct snd_ff *ff)
 }
 
 int snd_ff_stream_reserve_duplex(struct snd_ff *ff, unsigned int rate,
-				 unsigned int frames_per_period)
+				 unsigned int frames_per_period,
+				 unsigned int frames_per_buffer)
 {
 	unsigned int curr_rate;
 	enum snd_ff_clock_src src;
@@ -153,7 +154,7 @@ int snd_ff_stream_reserve_duplex(struct snd_ff *ff, unsigned int rate,
 			return err;
 
 		err = amdtp_domain_set_events_per_period(&ff->domain,
-							 frames_per_period, 0);
+					frames_per_period, frames_per_buffer);
 		if (err < 0) {
 			fw_iso_resources_free(&ff->tx_resources);
 			fw_iso_resources_free(&ff->rx_resources);

sound/firewire/fireface/ff.h

@@ -140,7 +140,8 @@ int snd_ff_stream_get_multiplier_mode(enum cip_sfc sfc,
 int snd_ff_stream_init_duplex(struct snd_ff *ff);
 void snd_ff_stream_destroy_duplex(struct snd_ff *ff);
 int snd_ff_stream_reserve_duplex(struct snd_ff *ff, unsigned int rate,
-				 unsigned int frames_per_period);
+				 unsigned int frames_per_period,
+				 unsigned int frames_per_buffer);
 int snd_ff_stream_start_duplex(struct snd_ff *ff, unsigned int rate);
 void snd_ff_stream_stop_duplex(struct snd_ff *ff);
 void snd_ff_stream_update_duplex(struct snd_ff *ff);