ALSA: firewire-lib: code refactoring for parameters of packet queue and IRQ timing

Although the parameter for packet queue and IRQ timing is calculated when
AMDTP stream starts, the calculated parameters are the same between
streams in AMDTP domain.

This commit moves the calculation and decide the parameters when AMDTP
domain starts.
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20200508043635.349339-5-o-takashi@sakamocchi.jpSigned-off-by: Takashi Iwai <tiwai@suse.de>

sound/firewire/amdtp-stream.c

@@ -957,13 +957,16 @@ static void amdtp_stream_first_callback(struct fw_iso_context *context,
  * @speed: firewire speed code
  * @start_cycle: the isochronous cycle to start the context. Start immediately
  *		 if negative value is given.
+ * @queue_size: The number of packets in the queue.
+ * @idle_irq_interval: the interval to queue packet during initial state.
  *
  * The stream cannot be started until it has been configured with
  * amdtp_stream_set_parameters() and it must be started before any PCM or MIDI
  * device can be started.
  */
 static int amdtp_stream_start(struct amdtp_stream *s, int channel, int speed,
-			      int start_cycle)
+			      int start_cycle, unsigned int queue_size,
+			      unsigned int idle_irq_interval)
 {
 	static const struct {
 		unsigned int data_block;
@@ -978,9 +981,6 @@ static int amdtp_stream_start(struct amdtp_stream *s, int channel, int speed,
 		[CIP_SFC_176400] = {  0,   67 },
 	};
 	bool is_irq_target = (s == s->domain->irq_target);
-	unsigned int events_per_buffer;
-	unsigned int events_per_period;
-	unsigned int idle_irq_interval;
 	unsigned int ctx_header_size;
 	unsigned int max_ctx_payload_size;
 	enum dma_data_direction dir;
@@ -1032,30 +1032,11 @@ static int amdtp_stream_start(struct amdtp_stream *s, int channel, int speed,
 			max_ctx_payload_size -= IT_PKT_HEADER_SIZE_CIP;
 	}
 
-	// This is a case that AMDTP streams in domain run just for MIDI
-	// substream. Use the number of events equivalent to 10 msec as
-	// interval of hardware IRQ.
-	events_per_buffer = s->domain->events_per_buffer;
-	events_per_period = s->domain->events_per_period;
-	if (events_per_period == 0)
-		events_per_period = amdtp_rate_table[s->sfc] / 100;
-	if (events_per_buffer == 0)
-		events_per_buffer = events_per_period * 3;
-
-	idle_irq_interval = DIV_ROUND_UP(CYCLES_PER_SECOND * events_per_period,
-					 amdtp_rate_table[s->sfc]);
-	s->queue_size = DIV_ROUND_UP(CYCLES_PER_SECOND * events_per_buffer,
-				     amdtp_rate_table[s->sfc]);
-
-	err = iso_packets_buffer_init(&s->buffer, s->unit, s->queue_size,
+	err = iso_packets_buffer_init(&s->buffer, s->unit, queue_size,
 				      max_ctx_payload_size, dir);
 	if (err < 0)
 		goto err_unlock;
-
-	if (is_irq_target) {
-		s->ctx_data.rx.events_per_period = events_per_period;
-		s->ctx_data.rx.event_count = 0;
-	}
+	s->queue_size = queue_size;
 
 	s->context = fw_iso_context_create(fw_parent_device(s->unit)->card,
 					  type, channel, speed, ctx_header_size,
@@ -1341,6 +1322,10 @@ static int get_current_cycle_time(struct fw_card *fw_card, int *cur_cycle)
  */
 int amdtp_domain_start(struct amdtp_domain *d, unsigned int ir_delay_cycle)
 {
+	unsigned int events_per_buffer = d->events_per_buffer;
+	unsigned int events_per_period = d->events_per_period;
+	unsigned int idle_irq_interval;
+	unsigned int queue_size;
 	struct amdtp_stream *s;
 	int cycle;
 	int err;
@@ -1354,6 +1339,17 @@ int amdtp_domain_start(struct amdtp_domain *d, unsigned int ir_delay_cycle)
 		return -ENXIO;
 	d->irq_target = s;
 
+	// This is a case that AMDTP streams in domain run just for MIDI
+	// substream. Use the number of events equivalent to 10 msec as
+	// interval of hardware IRQ.
+	if (events_per_period == 0)
+		events_per_period = amdtp_rate_table[d->irq_target->sfc] / 100;
+	if (events_per_buffer == 0)
+		events_per_buffer = events_per_period * 3;
+
+	queue_size = DIV_ROUND_UP(CYCLES_PER_SECOND * events_per_buffer,
+				  amdtp_rate_table[d->irq_target->sfc]);
+
 	if (ir_delay_cycle > 0) {
 		struct fw_card *fw_card = fw_parent_device(s->unit)->card;
 
@@ -1394,14 +1390,20 @@ int amdtp_domain_start(struct amdtp_domain *d, unsigned int ir_delay_cycle)
 
 		if (s != d->irq_target) {
 			err = amdtp_stream_start(s, s->channel, s->speed,
-						 cycle_match);
+						 cycle_match, queue_size, 0);
 			if (err < 0)
 				goto error;
 		}
 	}
 
 	s = d->irq_target;
-	err = amdtp_stream_start(s, s->channel, s->speed, -1);
+	s->ctx_data.rx.events_per_period = events_per_period;
+	s->ctx_data.rx.event_count = 0;
+
+	idle_irq_interval = DIV_ROUND_UP(CYCLES_PER_SECOND * events_per_period,
+					 amdtp_rate_table[d->irq_target->sfc]);
+	err = amdtp_stream_start(s, s->channel, s->speed, -1, queue_size,
+				 idle_irq_interval);
 	if (err < 0)
 		goto error;