ALSA: bebob: share PCM buffer size for both direction

This commit allows ALSA bebob 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 <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Takashi Iwai <[e-mail]>

sound/firewire/bebob/bebob.h

···
 int snd_bebob_stream_discover(struct snd_bebob *bebob);
 int snd_bebob_stream_init_duplex(struct snd_bebob *bebob);
 int snd_bebob_stream_reserve_duplex(struct snd_bebob *bebob, unsigned int rate,
-				    unsigned int frames_per_period);
+				    unsigned int frames_per_period,
+				    unsigned int frames_per_buffer);
 int snd_bebob_stream_start_duplex(struct snd_bebob *bebob);
 void snd_bebob_stream_stop_duplex(struct snd_bebob *bebob);
 void snd_bebob_stream_destroy_duplex(struct snd_bebob *bebob);

sound/firewire/bebob/bebob_midi.c

···
 		return err;
 
 	mutex_lock(&bebob->mutex);
-	err = snd_bebob_stream_reserve_duplex(bebob, 0, 0);
+	err = snd_bebob_stream_reserve_duplex(bebob, 0, 0, 0);
 	if (err >= 0) {
 		++bebob->substreams_counter;
 		err = snd_bebob_stream_start_duplex(bebob);

sound/firewire/bebob/bebob_pcm.c

···
 	if (src == SND_BEBOB_CLOCK_TYPE_EXTERNAL ||
 	    (bebob->substreams_counter > 0 && d->events_per_period > 0)) {
 		unsigned int frames_per_period = d->events_per_period;
+		unsigned int frames_per_buffer = d->events_per_buffer;
 		unsigned int sampling_rate;
 
 		err = spec->get(bebob, &sampling_rate);
···
 			err = snd_pcm_hw_constraint_minmax(substream->runtime,
 					SNDRV_PCM_HW_PARAM_PERIOD_SIZE,
 					frames_per_period, frames_per_period);
+			if (err < 0) {
+				mutex_unlock(&bebob->mutex);
+				goto err_locked;
+			}
+
+			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(&bebob->mutex);
 				goto err_locked;
···
 	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(&bebob->mutex);
 		err = snd_bebob_stream_reserve_duplex(bebob, rate,
-						      frames_per_period);
+					frames_per_period, frames_per_buffer);
 		if (err >= 0)
 			++bebob->substreams_counter;
 		mutex_unlock(&bebob->mutex);

sound/firewire/bebob/bebob_stream.c

···
 }
 
 int snd_bebob_stream_reserve_duplex(struct snd_bebob *bebob, unsigned int rate,
-				    unsigned int frames_per_period)
+				    unsigned int frames_per_period,
+				    unsigned int frames_per_buffer)
 {
 	unsigned int curr_rate;
 	int err;
···
 		}
 
 		err = amdtp_domain_set_events_per_period(&bebob->domain,
-							 frames_per_period, 0);
+					frames_per_period, frames_per_buffer);
 		if (err < 0) {
 			cmp_connection_release(&bebob->out_conn);
 			cmp_connection_release(&bebob->in_conn);