ALSA: firewire-motu: reserve/release isochronous resources in pcm.hw_params/hw_free callbacks

Once allocated, isochronous resources are available for packet
streaming, even if the streaming is cancelled. For this reason,
current implementation handles allocation of the resources and
starting packet streaming at the same time. However, this brings
complicated procedure to start packet streaming.

This commit separates the allocation and starting. The allocation is
done in pcm.hw_params callback and available till pcm.hw_free callback.
Even if any XRUN occurs, pcm.prepare callback is done to restart
packet streaming without releasing/allocating the resources.

There are two points to stop packet streaming; in pcm.hw_params and
pcm.prepare callbacks. The former point is a case that packet streaming
is already started for any MIDI substream then packet streaming is
requested with different sampling transfer frequency for any PCM
substream. The latter point is cases of any XRUN or packet queueing
error.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

1 files changed, 56 insertions, 44 deletions

diff --git a/sound/firewire/motu/motu-stream.c b/sound/firewire/motu/motu-stream.c
index 53c43848b137..5630a8f1f2f1 100644
--- a/sound/firewire/motu/motu-stream.c
+++ b/sound/firewire/motu/motu-stream.c
@@ -60,20 +60,12 @@ static int keep_resources(struct snd_motu *motu, unsigned int rate,
 				fw_parent_device(motu->unit)->max_speed);
 }
 
-static int begin_session(struct snd_motu *motu, unsigned int rate)
+static int begin_session(struct snd_motu *motu)
 {
 	__be32 reg;
 	u32 data;
 	int err;
 
-	err = keep_resources(motu, rate, &motu->tx_stream);
-	if (err < 0)
-		return err;
-
-	err = keep_resources(motu, rate, &motu->rx_stream);
-	if (err < 0)
-		return err;
-
 	// Configure the unit to start isochronous communication.
 	err = snd_motu_transaction_read(motu, ISOC_COMM_CONTROL_OFFSET, &reg,
 					sizeof(reg));
@@ -116,9 +108,6 @@ static void finish_session(struct snd_motu *motu)
 	reg = cpu_to_be32(data);
 	snd_motu_transaction_write(motu, ISOC_COMM_CONTROL_OFFSET, &reg,
 				   sizeof(reg));
-
-	fw_iso_resources_free(&motu->tx_resources);
-	fw_iso_resources_free(&motu->rx_resources);
 }
 
 static int start_isoc_ctx(struct snd_motu *motu, struct amdtp_stream *stream)
@@ -136,11 +125,8 @@ static int start_isoc_ctx(struct snd_motu *motu, struct amdtp_stream *stream)
 	if (err < 0)
 		return err;
 
-	if (!amdtp_stream_wait_callback(stream, CALLBACK_TIMEOUT)) {
-		amdtp_stream_stop(stream);
-		fw_iso_resources_free(resources);
+	if (!amdtp_stream_wait_callback(stream, CALLBACK_TIMEOUT))
 		return -ETIMEDOUT;
-	}
 
 	return 0;
 }
@@ -172,6 +158,56 @@ int snd_motu_stream_cache_packet_formats(struct snd_motu *motu)
 	return 0;
 }
 
+int snd_motu_stream_reserve_duplex(struct snd_motu *motu, unsigned int rate)
+{
+	unsigned int curr_rate;
+	int err;
+
+	err = motu->spec->protocol->get_clock_rate(motu, &curr_rate);
+	if (err < 0)
+		return err;
+	if (rate == 0)
+		rate = curr_rate;
+
+	if (motu->substreams_counter == 0 || curr_rate != rate) {
+		finish_session(motu);
+
+		fw_iso_resources_free(&motu->tx_resources);
+		fw_iso_resources_free(&motu->rx_resources);
+
+		err = motu->spec->protocol->set_clock_rate(motu, rate);
+		if (err < 0) {
+			dev_err(&motu->unit->device,
+				"fail to set sampling rate: %d\n", err);
+			return err;
+		}
+
+		err = snd_motu_stream_cache_packet_formats(motu);
+		if (err < 0)
+			return err;
+
+		err = keep_resources(motu, rate, &motu->tx_stream);
+		if (err < 0)
+			return err;
+
+		err = keep_resources(motu, rate, &motu->rx_stream);
+		if (err < 0) {
+			fw_iso_resources_free(&motu->tx_resources);
+			return err;
+		}
+	}
+
+	return 0;
+}
+
+void snd_motu_stream_release_duplex(struct snd_motu *motu)
+{
+	if (motu->substreams_counter == 0) {
+		fw_iso_resources_free(&motu->tx_resources);
+		fw_iso_resources_free(&motu->rx_resources);
+	}
+}
+
 static int ensure_packet_formats(struct snd_motu *motu)
 {
 	__be32 reg;
@@ -198,46 +234,23 @@ static int ensure_packet_formats(struct snd_motu *motu)
 					  sizeof(reg));
 }
 
-int snd_motu_stream_start_duplex(struct snd_motu *motu, unsigned int rate)
+int snd_motu_stream_start_duplex(struct snd_motu *motu)
 {
-	const struct snd_motu_protocol *protocol = motu->spec->protocol;
-	unsigned int curr_rate;
 	int err = 0;
 
 	if (motu->substreams_counter == 0)
 		return 0;
 
-	err = snd_motu_stream_cache_packet_formats(motu);
-	if (err < 0)
-		return err;
-
-	// Stop stream if rate is different.
-	err = protocol->get_clock_rate(motu, &curr_rate);
-	if (err < 0) {
-		dev_err(&motu->unit->device,
-			"fail to get sampling rate: %d\n", err);
-		return err;
-	}
-	if (rate == 0)
-		rate = curr_rate;
-	if (rate != curr_rate ||
-	    amdtp_streaming_error(&motu->rx_stream) ||
+	if (amdtp_streaming_error(&motu->rx_stream) ||
 	    amdtp_streaming_error(&motu->tx_stream))
 		finish_session(motu);
 
 	if (!amdtp_stream_running(&motu->rx_stream)) {
-		err = protocol->set_clock_rate(motu, rate);
-		if (err < 0) {
-			dev_err(&motu->unit->device,
-				"fail to set sampling rate: %d\n", err);
-			return err;
-		}
-
 		err = ensure_packet_formats(motu);
 		if (err < 0)
 			return err;
 
-		err = begin_session(motu, rate);
+		err = begin_session(motu);
 		if (err < 0) {
 			dev_err(&motu->unit->device,
 				"fail to start isochronous comm: %d\n", err);
@@ -251,7 +264,7 @@ int snd_motu_stream_start_duplex(struct snd_motu *motu, unsigned int rate)
 			goto stop_streams;
 		}
 
-		err = protocol->switch_fetching_mode(motu, true);
+		err = motu->spec->protocol->switch_fetching_mode(motu, true);
 		if (err < 0) {
 			dev_err(&motu->unit->device,
 				"fail to enable frame fetching: %d\n", err);
@@ -264,7 +277,6 @@ int snd_motu_stream_start_duplex(struct snd_motu *motu, unsigned int rate)
 		if (err < 0) {
 			dev_err(&motu->unit->device,
 				"fail to start IR context: %d", err);
-			amdtp_stream_stop(&motu->rx_stream);
 			goto stop_streams;
 		}
 	}