sound: usb-audio: use multiple output URBs

Some newer USB MIDI interfaces use rather small packet sizes, so to get
enough bandwidth, we have to be able to send multiple packets in one USB
frame, so we have to use multiple URBs.
Signed-off-by: NClemens Ladisch <clemens@ladisch.de>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

sound/usb/usbmidi.c

@@ -62,6 +62,7 @@
  */
 #define ERROR_DELAY_JIFFIES (HZ / 10)
 
+#define OUTPUT_URBS 7
 #define INPUT_URBS 7
 
 
@@ -92,7 +93,7 @@ struct snd_usb_midi_endpoint;
 
 struct usb_protocol_ops {
 	void (*input)(struct snd_usb_midi_in_endpoint*, uint8_t*, int);
-	void (*output)(struct snd_usb_midi_out_endpoint*);
+	void (*output)(struct snd_usb_midi_out_endpoint *ep, struct urb *urb);
 	void (*output_packet)(struct urb*, uint8_t, uint8_t, uint8_t, uint8_t);
 	void (*init_out_endpoint)(struct snd_usb_midi_out_endpoint*);
 	void (*finish_out_endpoint)(struct snd_usb_midi_out_endpoint*);
@@ -118,8 +119,11 @@ struct snd_usb_midi {
 
 struct snd_usb_midi_out_endpoint {
 	struct snd_usb_midi* umidi;
-	struct urb* urb;
-	int urb_active;
+	struct out_urb_context {
+		struct urb *urb;
+		struct snd_usb_midi_out_endpoint *ep;
+	} urbs[OUTPUT_URBS];
+	unsigned int active_urbs;
 	int max_transfer;		/* size of urb buffer */
 	struct tasklet_struct tasklet;
 
@@ -253,10 +257,11 @@ static void snd_usbmidi_in_urb_complete(struct urb* urb)
 
 static void snd_usbmidi_out_urb_complete(struct urb* urb)
 {
-	struct snd_usb_midi_out_endpoint* ep = urb->context;
+	struct out_urb_context *context = urb->context;
+	struct snd_usb_midi_out_endpoint* ep = context->ep;
 
 	spin_lock(&ep->buffer_lock);
-	ep->urb_active = 0;
+	ep->active_urbs &= ~(1 << (context - ep->urbs));
 	spin_unlock(&ep->buffer_lock);
 	if (urb->status < 0) {
 		int err = snd_usbmidi_urb_error(urb->status);
@@ -276,23 +281,37 @@ static void snd_usbmidi_out_urb_complete(struct urb* urb)
  */
 static void snd_usbmidi_do_output(struct snd_usb_midi_out_endpoint* ep)
 {
-	struct urb* urb = ep->urb;
+	unsigned int urb_index;
+	struct urb* urb;
 	unsigned long flags;
 
 	spin_lock_irqsave(&ep->buffer_lock, flags);
-	if (ep->urb_active || ep->umidi->chip->shutdown) {
+	if (ep->umidi->chip->shutdown) {
 		spin_unlock_irqrestore(&ep->buffer_lock, flags);
 		return;
 	}
 
-	urb->transfer_buffer_length = 0;
-	ep->umidi->usb_protocol_ops->output(ep);
+	for (;;) {
+		urb = NULL;
+		for (urb_index = 0; urb_index < OUTPUT_URBS; ++urb_index)
+			if (!(ep->active_urbs & (1 << urb_index))) {
+				urb = ep->urbs[urb_index].urb;
+				break;
+			}
+		if (!urb)
+			break;
+
+		urb->transfer_buffer_length = 0;
+		ep->umidi->usb_protocol_ops->output(ep, urb);
+		if (urb->transfer_buffer_length == 0)
+			break;
 
-	if (urb->transfer_buffer_length > 0) {
 		dump_urb("sending", urb->transfer_buffer,
 			 urb->transfer_buffer_length);
 		urb->dev = ep->umidi->chip->dev;
-		ep->urb_active = snd_usbmidi_submit_urb(urb, GFP_ATOMIC) >= 0;
+		if (snd_usbmidi_submit_urb(urb, GFP_ATOMIC) < 0)
+			break;
+		ep->active_urbs |= 1 << urb_index;
 	}
 	spin_unlock_irqrestore(&ep->buffer_lock, flags);
 }
@@ -334,13 +353,14 @@ static void snd_usbmidi_error_timer(unsigned long data)
 static int send_bulk_static_data(struct snd_usb_midi_out_endpoint* ep,
 				 const void *data, int len)
 {
-	int err;
+	int err = 0;
 	void *buf = kmemdup(data, len, GFP_KERNEL);
 	if (!buf)
 		return -ENOMEM;
 	dump_urb("sending", buf, len);
-	err = usb_bulk_msg(ep->umidi->chip->dev, ep->urb->pipe, buf, len,
-			   NULL, 250);
+	if (ep->urbs[0].urb)
+		err = usb_bulk_msg(ep->umidi->chip->dev, ep->urbs[0].urb->pipe,
+				   buf, len, NULL, 250);
 	kfree(buf);
 	return err;
 }
@@ -558,9 +578,9 @@ static void snd_usbmidi_transmit_byte(struct usbmidi_out_port* port,
 	}
 }
 
-static void snd_usbmidi_standard_output(struct snd_usb_midi_out_endpoint* ep)
+static void snd_usbmidi_standard_output(struct snd_usb_midi_out_endpoint* ep,
+					struct urb *urb)
 {
-	struct urb* urb = ep->urb;
 	int p;
 
 	/* FIXME: lower-numbered ports can starve higher-numbered ports */
@@ -617,14 +637,15 @@ static void snd_usbmidi_novation_input(struct snd_usb_midi_in_endpoint* ep,
 	snd_usbmidi_input_data(ep, 0, &buffer[2], buffer[0] - 1);
 }
 
-static void snd_usbmidi_novation_output(struct snd_usb_midi_out_endpoint* ep)
+static void snd_usbmidi_novation_output(struct snd_usb_midi_out_endpoint* ep,
+					struct urb *urb)
 {
 	uint8_t* transfer_buffer;
 	int count;
 
 	if (!ep->ports[0].active)
 		return;
-	transfer_buffer = ep->urb->transfer_buffer;
+	transfer_buffer = urb->transfer_buffer;
 	count = snd_rawmidi_transmit(ep->ports[0].substream,
 				     &transfer_buffer[2],
 				     ep->max_transfer - 2);
@@ -634,7 +655,7 @@ static void snd_usbmidi_novation_output(struct snd_usb_midi_out_endpoint* ep)
 	}
 	transfer_buffer[0] = 0;
 	transfer_buffer[1] = count;
-	ep->urb->transfer_buffer_length = 2 + count;
+	urb->transfer_buffer_length = 2 + count;
 }
 
 static struct usb_protocol_ops snd_usbmidi_novation_ops = {
@@ -652,20 +673,21 @@ static void snd_usbmidi_raw_input(struct snd_usb_midi_in_endpoint* ep,
 	snd_usbmidi_input_data(ep, 0, buffer, buffer_length);
 }
 
-static void snd_usbmidi_raw_output(struct snd_usb_midi_out_endpoint* ep)
+static void snd_usbmidi_raw_output(struct snd_usb_midi_out_endpoint* ep,
+				   struct urb *urb)
 {
 	int count;
 
 	if (!ep->ports[0].active)
 		return;
 	count = snd_rawmidi_transmit(ep->ports[0].substream,
-				     ep->urb->transfer_buffer,
+				     urb->transfer_buffer,
 				     ep->max_transfer);
 	if (count < 1) {
 		ep->ports[0].active = 0;
 		return;
 	}
-	ep->urb->transfer_buffer_length = count;
+	urb->transfer_buffer_length = count;
 }
 
 static struct usb_protocol_ops snd_usbmidi_raw_ops = {
@@ -685,23 +707,25 @@ static void snd_usbmidi_us122l_input(struct snd_usb_midi_in_endpoint *ep,
 		snd_usbmidi_input_data(ep, 0, buffer, buffer_length);
 }
 
-static void snd_usbmidi_us122l_output(struct snd_usb_midi_out_endpoint *ep)
+static void snd_usbmidi_us122l_output(struct snd_usb_midi_out_endpoint *ep,
+				      struct urb *urb)
 {
 	int count;
 
 	if (!ep->ports[0].active)
 		return;
-	count = ep->urb->dev->speed == USB_SPEED_HIGH ? 1 : 2;
+	count = snd_usb_get_speed(ep->umidi->chip->dev) == USB_SPEED_HIGH
+		? 1 : 2;
 	count = snd_rawmidi_transmit(ep->ports[0].substream,
-				     ep->urb->transfer_buffer,
+				     urb->transfer_buffer,
 				     count);
 	if (count < 1) {
 		ep->ports[0].active = 0;
 		return;
 	}
 
-	memset(ep->urb->transfer_buffer + count, 0xFD, 9 - count);
-	ep->urb->transfer_buffer_length = count;
+	memset(urb->transfer_buffer + count, 0xFD, 9 - count);
+	urb->transfer_buffer_length = count;
 }
 
 static struct usb_protocol_ops snd_usbmidi_122l_ops = {
@@ -790,10 +814,11 @@ static void snd_usbmidi_emagic_input(struct snd_usb_midi_in_endpoint* ep,
 	}
 }
 
-static void snd_usbmidi_emagic_output(struct snd_usb_midi_out_endpoint* ep)
+static void snd_usbmidi_emagic_output(struct snd_usb_midi_out_endpoint* ep,
+				      struct urb *urb)
 {
 	int port0 = ep->current_port;
-	uint8_t* buf = ep->urb->transfer_buffer;
+	uint8_t* buf = urb->transfer_buffer;
 	int buf_free = ep->max_transfer;
 	int length, i;
 
@@ -833,7 +858,7 @@ static void snd_usbmidi_emagic_output(struct snd_usb_midi_out_endpoint* ep)
 		*buf = 0xff;
 		--buf_free;
 	}
-	ep->urb->transfer_buffer_length = ep->max_transfer - buf_free;
+	urb->transfer_buffer_length = ep->max_transfer - buf_free;
 }
 
 static struct usb_protocol_ops snd_usbmidi_emagic_ops = {
@@ -920,6 +945,14 @@ static struct snd_rawmidi_ops snd_usbmidi_input_ops = {
 	.trigger = snd_usbmidi_input_trigger
 };
 
+static void free_urb_and_buffer(struct snd_usb_midi *umidi, struct urb *urb,
+				unsigned int buffer_length)
+{
+	usb_buffer_free(umidi->chip->dev, buffer_length,
+			urb->transfer_buffer, urb->transfer_dma);
+	usb_free_urb(urb);
+}
+
 /*
  * Frees an input endpoint.
  * May be called when ep hasn't been initialized completely.
@@ -928,15 +961,10 @@ static void snd_usbmidi_in_endpoint_delete(struct snd_usb_midi_in_endpoint* ep)
 {
 	unsigned int i;
 
-	for (i = 0; i < INPUT_URBS; ++i) {
-		if (ep->urbs[i]) {
-			usb_buffer_free(ep->umidi->chip->dev,
-					ep->urbs[i]->transfer_buffer_length,
-					ep->urbs[i]->transfer_buffer,
-					ep->urbs[i]->transfer_dma);
-			usb_free_urb(ep->urbs[i]);
-		}
-	}
+	for (i = 0; i < INPUT_URBS; ++i)
+		if (ep->urbs[i])
+			free_urb_and_buffer(ep->umidi, ep->urbs[i],
+					    ep->urbs[i]->transfer_buffer_length);
 	kfree(ep);
 }
 
@@ -1009,12 +1037,12 @@ static unsigned int snd_usbmidi_count_bits(unsigned int x)
  */
 static void snd_usbmidi_out_endpoint_delete(struct snd_usb_midi_out_endpoint* ep)
 {
-	if (ep->urb) {
-		usb_buffer_free(ep->umidi->chip->dev, ep->max_transfer,
-				ep->urb->transfer_buffer,
-				ep->urb->transfer_dma);
-		usb_free_urb(ep->urb);
-	}
+	unsigned int i;
+
+	for (i = 0; i < OUTPUT_URBS; ++i)
+		if (ep->urbs[i].urb)
+			free_urb_and_buffer(ep->umidi, ep->urbs[i].urb,
+					    ep->max_transfer);
 	kfree(ep);
 }
 
@@ -1026,7 +1054,7 @@ static int snd_usbmidi_out_endpoint_create(struct snd_usb_midi* umidi,
 			 		   struct snd_usb_midi_endpoint* rep)
 {
 	struct snd_usb_midi_out_endpoint* ep;
-	int i;
+	unsigned int i;
 	unsigned int pipe;
 	void* buffer;
 
@@ -1036,35 +1064,42 @@ static int snd_usbmidi_out_endpoint_create(struct snd_usb_midi* umidi,
 		return -ENOMEM;
 	ep->umidi = umidi;
 
-	ep->urb = usb_alloc_urb(0, GFP_KERNEL);
-	if (!ep->urb) {
-		snd_usbmidi_out_endpoint_delete(ep);
-		return -ENOMEM;
+	for (i = 0; i < OUTPUT_URBS; ++i) {
+		ep->urbs[i].urb = usb_alloc_urb(0, GFP_KERNEL);
+		if (!ep->urbs[i].urb) {
+			snd_usbmidi_out_endpoint_delete(ep);
+			return -ENOMEM;
+		}
+		ep->urbs[i].ep = ep;
 	}
 	if (ep_info->out_interval)
 		pipe = usb_sndintpipe(umidi->chip->dev, ep_info->out_ep);
 	else
 		pipe = usb_sndbulkpipe(umidi->chip->dev, ep_info->out_ep);
 	if (umidi->chip->usb_id == USB_ID(0x0a92, 0x1020)) /* ESI M4U */
-		/* FIXME: we need more URBs to get reasonable bandwidth here: */
 		ep->max_transfer = 4;
 	else
 		ep->max_transfer = usb_maxpacket(umidi->chip->dev, pipe, 1);
-	buffer = usb_buffer_alloc(umidi->chip->dev, ep->max_transfer,
-				  GFP_KERNEL, &ep->urb->transfer_dma);
-	if (!buffer) {
-		snd_usbmidi_out_endpoint_delete(ep);
-		return -ENOMEM;
+	for (i = 0; i < OUTPUT_URBS; ++i) {
+		buffer = usb_buffer_alloc(umidi->chip->dev,
+					  ep->max_transfer, GFP_KERNEL,
+					  &ep->urbs[i].urb->transfer_dma);
+		if (!buffer) {
+			snd_usbmidi_out_endpoint_delete(ep);
+			return -ENOMEM;
+		}
+		if (ep_info->out_interval)
+			usb_fill_int_urb(ep->urbs[i].urb, umidi->chip->dev,
+					 pipe, buffer, ep->max_transfer,
+					 snd_usbmidi_out_urb_complete,
+					 &ep->urbs[i], ep_info->out_interval);
+		else
+			usb_fill_bulk_urb(ep->urbs[i].urb, umidi->chip->dev,
+					  pipe, buffer, ep->max_transfer,
+					  snd_usbmidi_out_urb_complete,
+					  &ep->urbs[i]);
+		ep->urbs[i].urb->transfer_flags = URB_NO_TRANSFER_DMA_MAP;
 	}
-	if (ep_info->out_interval)
-		usb_fill_int_urb(ep->urb, umidi->chip->dev, pipe, buffer,
-				 ep->max_transfer, snd_usbmidi_out_urb_complete,
-				 ep, ep_info->out_interval);
-	else
-		usb_fill_bulk_urb(ep->urb, umidi->chip->dev,
-				  pipe, buffer, ep->max_transfer,
-				  snd_usbmidi_out_urb_complete, ep);
-	ep->urb->transfer_flags = URB_NO_TRANSFER_DMA_MAP;
 
 	spin_lock_init(&ep->buffer_lock);
 	tasklet_init(&ep->tasklet, snd_usbmidi_out_tasklet, (unsigned long)ep);
@@ -1120,8 +1155,9 @@ void snd_usbmidi_disconnect(struct list_head* p)
 		struct snd_usb_midi_endpoint* ep = &umidi->endpoints[i];
 		if (ep->out)
 			tasklet_kill(&ep->out->tasklet);
-		if (ep->out && ep->out->urb) {
-			usb_kill_urb(ep->out->urb);
+		if (ep->out) {
+			for (j = 0; j < OUTPUT_URBS; ++j)
+				usb_kill_urb(ep->out->urbs[j].urb);
 			if (umidi->usb_protocol_ops->finish_out_endpoint)
 				umidi->usb_protocol_ops->finish_out_endpoint(ep->out);
 		}