ALSA: firewire-lib: transfer rx packets on-the-fly when replaying

Models in below series start transmission of packet after receiving the
sequence of packets:

 * Digidesign Digi00x family
 * RME Fireface series

Additionally, models in Tascam FireWire series start multiplexing PCM
frames into packets enough after receiving packets. It's required to
transfer packets on-the-fly for the above models according to nominal
sampling transfer frequency before starting sequence replay.

This commit allows drivers to decide whether the engine transfers packet
on-the-fly or not.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20210527122611.173711-4-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/firewire/amdtp-stream.c

@@ -577,10 +577,23 @@ static void pool_seq_descs(struct amdtp_stream *s, unsigned int count)
 {
 	struct amdtp_domain *d = s->domain;
 
-	if (!d->replay.enable || !s->ctx_data.rx.replay_target)
+	if (!d->replay.enable || !s->ctx_data.rx.replay_target) {
 		pool_ideal_seq_descs(s, count);
-	else
-		pool_replayed_seq(s, count);
+	} else {
+		if (!d->replay.on_the_fly) {
+			pool_replayed_seq(s, count);
+		} else {
+			struct amdtp_stream *tx = s->ctx_data.rx.replay_target;
+			const unsigned int cache_size = tx->ctx_data.tx.cache.size;
+			const unsigned int cache_head = s->ctx_data.rx.cache_head;
+			unsigned int cached_cycles = calculate_cached_cycle_count(tx, cache_head);
+
+			if (cached_cycles > count && cached_cycles > cache_size / 2)
+				pool_replayed_seq(s, count);
+			else
+				pool_ideal_seq_descs(s, count);
+		}
+	}
 }
 
 static void update_pcm_pointers(struct amdtp_stream *s,
@@ -1444,7 +1457,7 @@ static void irq_target_callback_skip(struct fw_iso_context *context, u32 tstamp,
 	skip_rx_packets(context, tstamp, header_length, header, private_data);
 	process_ctxs_in_domain(d);
 
-	if (d->replay.enable) {
+	if (d->replay.enable && !d->replay.on_the_fly) {
 		unsigned int rx_count = 0;
 		unsigned int rx_ready_count = 0;
 		struct amdtp_stream *rx;
@@ -1929,8 +1942,11 @@ static int make_association(struct amdtp_domain *d)
  *			 contexts.
  * @replay_seq: whether to replay the sequence of packet in IR context for the sequence of packet in
  *		IT context.
+ * @replay_on_the_fly: transfer rx packets according to nominal frequency, then begin to replay
+ *		       according to arrival of events in tx packets.
  */
-int amdtp_domain_start(struct amdtp_domain *d, unsigned int tx_init_skip_cycles, bool replay_seq)
+int amdtp_domain_start(struct amdtp_domain *d, unsigned int tx_init_skip_cycles, bool replay_seq,
+		       bool replay_on_the_fly)
 {
 	unsigned int events_per_buffer = d->events_per_buffer;
 	unsigned int events_per_period = d->events_per_period;
@@ -1944,6 +1960,7 @@ int amdtp_domain_start(struct amdtp_domain *d, unsigned int tx_init_skip_cycles,
 			return err;
 	}
 	d->replay.enable = replay_seq;
+	d->replay.on_the_fly = replay_on_the_fly;
 
 	// Select an IT context as IRQ target.
 	list_for_each_entry(s, &d->streams, list) {

sound/firewire/amdtp-stream.h

@@ -303,7 +303,8 @@ struct amdtp_domain {
 	} processing_cycle;
 
 	struct {
-		bool enable;
+		bool enable:1;
+		bool on_the_fly:1;
 	} replay;
 };
 
@@ -313,7 +314,8 @@ void amdtp_domain_destroy(struct amdtp_domain *d);
 int amdtp_domain_add_stream(struct amdtp_domain *d, struct amdtp_stream *s,
 			    int channel, int speed);
 
-int amdtp_domain_start(struct amdtp_domain *d, unsigned int tx_init_skip_cycles, bool replay_seq);
+int amdtp_domain_start(struct amdtp_domain *d, unsigned int tx_init_skip_cycles, bool replay_seq,
+		       bool replay_on_the_fly);
 void amdtp_domain_stop(struct amdtp_domain *d);
 
 static inline int amdtp_domain_set_events_per_period(struct amdtp_domain *d,

sound/firewire/bebob/bebob_stream.c

@@ -652,7 +652,7 @@ int snd_bebob_stream_start_duplex(struct snd_bebob *bebob)
 		// MEMO: In the early stage of packet streaming, the device transfers NODATA packets.
 		// After several hundred cycles, it begins to multiplex event into the packet with
 		// syt information.
-		err = amdtp_domain_start(&bebob->domain, tx_init_skip_cycles, false);
+		err = amdtp_domain_start(&bebob->domain, tx_init_skip_cycles, false, false);
 		if (err < 0)
 			goto error;
 

sound/firewire/dice/dice-stream.c

@@ -459,7 +459,7 @@ int snd_dice_stream_start_duplex(struct snd_dice *dice)
 			goto error;
 		}
 
-		err = amdtp_domain_start(&dice->domain, 0, false);
+		err = amdtp_domain_start(&dice->domain, 0, false, false);
 		if (err < 0)
 			goto error;
 

sound/firewire/digi00x/digi00x-stream.c

@@ -375,7 +375,7 @@ int snd_dg00x_stream_start_duplex(struct snd_dg00x *dg00x)
 		if (err < 0)
 			goto error;
 
-		err = amdtp_domain_start(&dg00x->domain, 0, false);
+		err = amdtp_domain_start(&dg00x->domain, 0, false, false);
 		if (err < 0)
 			goto error;
 

sound/firewire/fireface/ff-stream.c

@@ -199,7 +199,7 @@ int snd_ff_stream_start_duplex(struct snd_ff *ff, unsigned int rate)
 		if (err < 0)
 			goto error;
 
-		err = amdtp_domain_start(&ff->domain, 0, false);
+		err = amdtp_domain_start(&ff->domain, 0, false, false);
 		if (err < 0)
 			goto error;
 

sound/firewire/fireworks/fireworks_stream.c

@@ -272,7 +272,7 @@ int snd_efw_stream_start_duplex(struct snd_efw *efw)
 		if (err < 0)
 			goto error;
 
-		err = amdtp_domain_start(&efw->domain, 0, false);
+		err = amdtp_domain_start(&efw->domain, 0, false, false);
 		if (err < 0)
 			goto error;
 

sound/firewire/motu/motu-stream.c

@@ -260,7 +260,7 @@ int snd_motu_stream_start_duplex(struct snd_motu *motu)
 		if (err < 0)
 			goto stop_streams;
 
-		err = amdtp_domain_start(&motu->domain, 0, false);
+		err = amdtp_domain_start(&motu->domain, 0, false, false);
 		if (err < 0)
 			goto stop_streams;
 

sound/firewire/oxfw/oxfw-stream.c

@@ -354,7 +354,7 @@ int snd_oxfw_stream_start_duplex(struct snd_oxfw *oxfw)
 			}
 		}
 
-		err = amdtp_domain_start(&oxfw->domain, 0, false);
+		err = amdtp_domain_start(&oxfw->domain, 0, false, false);
 		if (err < 0)
 			goto error;
 

sound/firewire/tascam/tascam-stream.c

@@ -473,7 +473,7 @@ int snd_tscm_stream_start_duplex(struct snd_tscm *tscm, unsigned int rate)
 		if (err < 0)
 			goto error;
 
-		err = amdtp_domain_start(&tscm->domain, 0, false);
+		err = amdtp_domain_start(&tscm->domain, 0, false, false);
 		if (err < 0)
 			return err;