ALSA: firewire-lib: replace pointer callback to flush isoc contexts in AMDTP domain

An isoc context for AMDTP stream is flushed to queue packet
by a call of pcm.pointer. This commit extends this for AMDTP
domain.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20191018061911.24909-3-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/firewire/amdtp-stream.c

@@ -1099,35 +1099,44 @@ err_unlock:
 }
 
 /**
- * amdtp_stream_pcm_pointer - get the PCM buffer position
+ * amdtp_domain_stream_pcm_pointer - get the PCM buffer position
+ * @d: the AMDTP domain.
  * @s: the AMDTP stream that transports the PCM data
  *
  * Returns the current buffer position, in frames.
  */
-unsigned long amdtp_stream_pcm_pointer(struct amdtp_stream *s)
+unsigned long amdtp_domain_stream_pcm_pointer(struct amdtp_domain *d,
+					      struct amdtp_stream *s)
 {
-	/*
-	 * This function is called in software IRQ context of period_tasklet or
-	 * process context.
-	 *
-	 * When the software IRQ context was scheduled by software IRQ context
-	 * of IR/IT contexts, queued packets were already handled. Therefore,
-	 * no need to flush the queue in buffer anymore.
-	 *
-	 * When the process context reach here, some packets will be already
-	 * queued in the buffer. These packets should be handled immediately
-	 * to keep better granularity of PCM pointer.
-	 *
-	 * Later, the process context will sometimes schedules software IRQ
-	 * context of the period_tasklet. Then, no need to flush the queue by
-	 * the same reason as described for IR/IT contexts.
-	 */
-	if (!in_interrupt() && amdtp_stream_running(s))
-		fw_iso_context_flush_completions(s->context);
+	struct amdtp_stream *irq_target = d->irq_target;
+
+	if (irq_target && amdtp_stream_running(irq_target)) {
+		// This function is called in software IRQ context of
+		// period_tasklet or process context.
+		//
+		// When the software IRQ context was scheduled by software IRQ
+		// context of IT contexts, queued packets were already handled.
+		// Therefore, no need to flush the queue in buffer furthermore.
+		//
+		// When the process context reach here, some packets will be
+		// already queued in the buffer. These packets should be handled
+		// immediately to keep better granularity of PCM pointer.
+		//
+		// Later, the process context will sometimes schedules software
+		// IRQ context of the period_tasklet. Then, no need to flush the
+		// queue by the same reason as described in the above
+		if (!in_interrupt()) {
+			// Queued packet should be processed without any kernel
+			// preemption to keep latency against bus cycle.
+			preempt_disable();
+			fw_iso_context_flush_completions(irq_target->context);
+			preempt_enable();
+		}
+	}
 
 	return READ_ONCE(s->pcm_buffer_pointer);
 }
-EXPORT_SYMBOL(amdtp_stream_pcm_pointer);
+EXPORT_SYMBOL_GPL(amdtp_domain_stream_pcm_pointer);
 
 /**
  * amdtp_stream_pcm_ack - acknowledge queued PCM frames

sound/firewire/amdtp-stream.h

@@ -198,7 +198,6 @@ int amdtp_stream_add_pcm_hw_constraints(struct amdtp_stream *s,
 					struct snd_pcm_runtime *runtime);
 
 void amdtp_stream_pcm_prepare(struct amdtp_stream *s);
-unsigned long amdtp_stream_pcm_pointer(struct amdtp_stream *s);
 int amdtp_stream_pcm_ack(struct amdtp_stream *s);
 void amdtp_stream_pcm_abort(struct amdtp_stream *s);
 
@@ -302,4 +301,6 @@ static inline int amdtp_domain_set_events_per_period(struct amdtp_domain *d,
 	return 0;
 }
 
+unsigned long amdtp_domain_stream_pcm_pointer(struct amdtp_domain *d,
+					      struct amdtp_stream *s);
 #endif

sound/firewire/bebob/bebob_pcm.c

@@ -313,17 +313,19 @@ pcm_playback_trigger(struct snd_pcm_substream *substream, int cmd)
 	return 0;
 }
 
-static snd_pcm_uframes_t
-pcm_capture_pointer(struct snd_pcm_substream *sbstrm)
+static snd_pcm_uframes_t pcm_capture_pointer(struct snd_pcm_substream *sbstrm)
 {
 	struct snd_bebob *bebob = sbstrm->private_data;
-	return amdtp_stream_pcm_pointer(&bebob->tx_stream);
+
+	return amdtp_domain_stream_pcm_pointer(&bebob->domain,
+					       &bebob->tx_stream);
 }
-static snd_pcm_uframes_t
-pcm_playback_pointer(struct snd_pcm_substream *sbstrm)
+static snd_pcm_uframes_t pcm_playback_pointer(struct snd_pcm_substream *sbstrm)
 {
 	struct snd_bebob *bebob = sbstrm->private_data;
-	return amdtp_stream_pcm_pointer(&bebob->rx_stream);
+
+	return amdtp_domain_stream_pcm_pointer(&bebob->domain,
+					       &bebob->rx_stream);
 }
 
 static int pcm_capture_ack(struct snd_pcm_substream *substream)

sound/firewire/dice/dice-pcm.c

@@ -379,14 +379,14 @@ static snd_pcm_uframes_t capture_pointer(struct snd_pcm_substream *substream)
 	struct snd_dice *dice = substream->private_data;
 	struct amdtp_stream *stream = &dice->tx_stream[substream->pcm->device];
 
-	return amdtp_stream_pcm_pointer(stream);
+	return amdtp_domain_stream_pcm_pointer(&dice->domain, stream);
 }
 static snd_pcm_uframes_t playback_pointer(struct snd_pcm_substream *substream)
 {
 	struct snd_dice *dice = substream->private_data;
 	struct amdtp_stream *stream = &dice->rx_stream[substream->pcm->device];
 
-	return amdtp_stream_pcm_pointer(stream);
+	return amdtp_domain_stream_pcm_pointer(&dice->domain, stream);
 }
 
 static int capture_ack(struct snd_pcm_substream *substream)

sound/firewire/digi00x/digi00x-pcm.c

@@ -301,14 +301,14 @@ static snd_pcm_uframes_t pcm_capture_pointer(struct snd_pcm_substream *sbstrm)
 {
 	struct snd_dg00x *dg00x = sbstrm->private_data;
 
-	return amdtp_stream_pcm_pointer(&dg00x->tx_stream);
+	return amdtp_domain_stream_pcm_pointer(&dg00x->domain, &dg00x->tx_stream);
 }
 
 static snd_pcm_uframes_t pcm_playback_pointer(struct snd_pcm_substream *sbstrm)
 {
 	struct snd_dg00x *dg00x = sbstrm->private_data;
 
-	return amdtp_stream_pcm_pointer(&dg00x->rx_stream);
+	return amdtp_domain_stream_pcm_pointer(&dg00x->domain, &dg00x->rx_stream);
 }
 
 static int pcm_capture_ack(struct snd_pcm_substream *substream)

sound/firewire/fireface/ff-pcm.c

@@ -341,14 +341,14 @@ static snd_pcm_uframes_t pcm_capture_pointer(struct snd_pcm_substream *sbstrm)
 {
 	struct snd_ff *ff = sbstrm->private_data;
 
-	return amdtp_stream_pcm_pointer(&ff->tx_stream);
+	return amdtp_domain_stream_pcm_pointer(&ff->domain, &ff->tx_stream);
 }
 
 static snd_pcm_uframes_t pcm_playback_pointer(struct snd_pcm_substream *sbstrm)
 {
 	struct snd_ff *ff = sbstrm->private_data;
 
-	return amdtp_stream_pcm_pointer(&ff->rx_stream);
+	return amdtp_domain_stream_pcm_pointer(&ff->domain, &ff->rx_stream);
 }
 
 static int pcm_capture_ack(struct snd_pcm_substream *substream)

sound/firewire/fireworks/fireworks_pcm.c

@@ -348,12 +348,14 @@ static int pcm_playback_trigger(struct snd_pcm_substream *substream, int cmd)
 static snd_pcm_uframes_t pcm_capture_pointer(struct snd_pcm_substream *sbstrm)
 {
 	struct snd_efw *efw = sbstrm->private_data;
-	return amdtp_stream_pcm_pointer(&efw->tx_stream);
+
+	return amdtp_domain_stream_pcm_pointer(&efw->domain, &efw->tx_stream);
 }
 static snd_pcm_uframes_t pcm_playback_pointer(struct snd_pcm_substream *sbstrm)
 {
 	struct snd_efw *efw = sbstrm->private_data;
-	return amdtp_stream_pcm_pointer(&efw->rx_stream);
+
+	return amdtp_domain_stream_pcm_pointer(&efw->domain, &efw->rx_stream);
 }
 
 static int pcm_capture_ack(struct snd_pcm_substream *substream)

sound/firewire/motu/motu-pcm.c

@@ -320,13 +320,13 @@ static snd_pcm_uframes_t capture_pointer(struct snd_pcm_substream *substream)
 {
 	struct snd_motu *motu = substream->private_data;
 
-	return amdtp_stream_pcm_pointer(&motu->tx_stream);
+	return amdtp_domain_stream_pcm_pointer(&motu->domain, &motu->tx_stream);
 }
 static snd_pcm_uframes_t playback_pointer(struct snd_pcm_substream *substream)
 {
 	struct snd_motu *motu = substream->private_data;
 
-	return amdtp_stream_pcm_pointer(&motu->rx_stream);
+	return amdtp_domain_stream_pcm_pointer(&motu->domain, &motu->rx_stream);
 }
 
 static int capture_ack(struct snd_pcm_substream *substream)

sound/firewire/oxfw/oxfw-pcm.c

@@ -393,13 +393,13 @@ static snd_pcm_uframes_t pcm_capture_pointer(struct snd_pcm_substream *sbstm)
 {
 	struct snd_oxfw *oxfw = sbstm->private_data;
 
-	return amdtp_stream_pcm_pointer(&oxfw->tx_stream);
+	return amdtp_domain_stream_pcm_pointer(&oxfw->domain, &oxfw->tx_stream);
 }
 static snd_pcm_uframes_t pcm_playback_pointer(struct snd_pcm_substream *sbstm)
 {
 	struct snd_oxfw *oxfw = sbstm->private_data;
 
-	return amdtp_stream_pcm_pointer(&oxfw->rx_stream);
+	return amdtp_domain_stream_pcm_pointer(&oxfw->domain, &oxfw->rx_stream);
 }
 
 static int pcm_capture_ack(struct snd_pcm_substream *substream)

sound/firewire/tascam/tascam-pcm.c

@@ -230,14 +230,14 @@ static snd_pcm_uframes_t pcm_capture_pointer(struct snd_pcm_substream *sbstrm)
 {
 	struct snd_tscm *tscm = sbstrm->private_data;
 
-	return amdtp_stream_pcm_pointer(&tscm->tx_stream);
+	return amdtp_domain_stream_pcm_pointer(&tscm->domain, &tscm->tx_stream);
 }
 
 static snd_pcm_uframes_t pcm_playback_pointer(struct snd_pcm_substream *sbstrm)
 {
 	struct snd_tscm *tscm = sbstrm->private_data;
 
-	return amdtp_stream_pcm_pointer(&tscm->rx_stream);
+	return amdtp_domain_stream_pcm_pointer(&tscm->domain, &tscm->rx_stream);
 }
 
 static int pcm_capture_ack(struct snd_pcm_substream *substream)