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 <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20191017155424.885-3-o-takashi@sakamocchi.jpSigned-off-by: Takashi Iwai <tiwai@suse.de>

sound/firewire/bebob/bebob.h

@@ -218,7 +218,8 @@ int snd_bebob_stream_get_clock_src(struct snd_bebob *bebob,
 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

@@ -17,7 +17,7 @@ static int midi_open(struct snd_rawmidi_substream *substream)
 		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

@@ -157,6 +157,7 @@ static int pcm_open(struct snd_pcm_substream *substream)
 	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);
@@ -178,6 +179,14 @@ static int pcm_open(struct snd_pcm_substream *substream)
 				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;
+			}
 		}
 	}
 
@@ -213,10 +222,11 @@ 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(&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

@@ -555,7 +555,8 @@ static int keep_resources(struct snd_bebob *bebob, struct amdtp_stream *stream,
 }
 
 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;
@@ -610,7 +611,7 @@ int snd_bebob_stream_reserve_duplex(struct snd_bebob *bebob, unsigned int rate,
 		}
 
 		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);