ALSA: firewire-motu: share PCM buffer size for both direction

This commit allows ALSA firewire-motu 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/20191017155424.885-9-o-takashi@sakamocchi.jpSigned-off-by: Takashi Iwai <tiwai@suse.de>

sound/firewire/motu/motu-midi.c

@@ -17,7 +17,7 @@ static int midi_open(struct snd_rawmidi_substream *substream)
 
 	mutex_lock(&motu->mutex);
 
-	err = snd_motu_stream_reserve_duplex(motu, 0, 0);
+	err = snd_motu_stream_reserve_duplex(motu, 0, 0, 0);
 	if (err >= 0) {
 		++motu->substreams_counter;
 		err = snd_motu_stream_start_duplex(motu);

sound/firewire/motu/motu-pcm.c

@@ -162,6 +162,7 @@ static int pcm_open(struct snd_pcm_substream *substream)
 	if (src != SND_MOTU_CLOCK_SOURCE_INTERNAL ||
 	    (motu->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 rate;
 
 		err = protocol->get_clock_rate(motu, &rate);
@@ -179,6 +180,14 @@ static int pcm_open(struct snd_pcm_substream *substream)
 				mutex_unlock(&motu->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(&motu->mutex);
+				goto err_locked;
+			}
 		}
 	}
 
@@ -216,10 +225,11 @@ 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(&motu->mutex);
 		err = snd_motu_stream_reserve_duplex(motu, rate,
-						     frames_per_period);
+					frames_per_period, frames_per_buffer);
 		if (err >= 0)
 			++motu->substreams_counter;
 		mutex_unlock(&motu->mutex);

sound/firewire/motu/motu-stream.c

@@ -134,7 +134,8 @@ int snd_motu_stream_cache_packet_formats(struct snd_motu *motu)
 }
 
 int snd_motu_stream_reserve_duplex(struct snd_motu *motu, unsigned int rate,
-				   unsigned int frames_per_period)
+				   unsigned int frames_per_period,
+				   unsigned int frames_per_buffer)
 {
 	unsigned int curr_rate;
 	int err;
@@ -174,7 +175,7 @@ int snd_motu_stream_reserve_duplex(struct snd_motu *motu, unsigned int rate,
 		}
 
 		err = amdtp_domain_set_events_per_period(&motu->domain,
-							 frames_per_period, 0);
+					frames_per_period, frames_per_buffer);
 		if (err < 0) {
 			fw_iso_resources_free(&motu->tx_resources);
 			fw_iso_resources_free(&motu->rx_resources);

sound/firewire/motu/motu.h

@@ -155,7 +155,8 @@ int snd_motu_stream_init_duplex(struct snd_motu *motu);
 void snd_motu_stream_destroy_duplex(struct snd_motu *motu);
 int snd_motu_stream_cache_packet_formats(struct snd_motu *motu);
 int snd_motu_stream_reserve_duplex(struct snd_motu *motu, unsigned int rate,
-				   unsigned int frames_per_period);
+				   unsigned int frames_per_period,
+				   unsigned int frames_per_buffer);
 int snd_motu_stream_start_duplex(struct snd_motu *motu);
 void snd_motu_stream_stop_duplex(struct snd_motu *motu);
 int snd_motu_stream_lock_try(struct snd_motu *motu);