sound: usb-audio: add MIDI drain callback

[sfrench/cifs-2.6.git] / sound / usb / usbmidi.c

diff --git a/sound/usb/usbmidi.c b/sound/usb/usbmidi.c
index 32d70cc046e789d32d122051b5364564376f100e..0eff19ceb7e1f9d74653d80c402d3930a6be8bf8 100644 (file)
--- a/sound/usb/usbmidi.c
+++ b/sound/usb/usbmidi.c
@@ -45,6 +45,7 @@
 #include <linux/slab.h>
 #include <linux/timer.h>
 #include <linux/usb.h>
+#include <linux/wait.h>
 #include <sound/core.h>
 #include <sound/rawmidi.h>
 #include <sound/asequencer.h>
@@ -124,9 +125,10 @@ struct snd_usb_midi_out_endpoint {
                struct snd_usb_midi_out_endpoint *ep;
        } urbs[OUTPUT_URBS];
        unsigned int active_urbs;
+       unsigned int drain_urbs;
        int max_transfer;               /* size of urb buffer */
        struct tasklet_struct tasklet;
-
+       unsigned int next_urb;
        spinlock_t buffer_lock;
 
        struct usbmidi_out_port {
@@ -145,6 +147,8 @@ struct snd_usb_midi_out_endpoint {
                uint8_t data[2];
        } ports[0x10];
        int current_port;
+
+       wait_queue_head_t drain_wait;
 };
 
 struct snd_usb_midi_in_endpoint {
@@ -259,9 +263,15 @@ static void snd_usbmidi_out_urb_complete(struct urb* urb)
 {
        struct out_urb_context *context = urb->context;
        struct snd_usb_midi_out_endpoint* ep = context->ep;
+       unsigned int urb_index;
 
        spin_lock(&ep->buffer_lock);
-       ep->active_urbs &= ~(1 << (context - ep->urbs));
+       urb_index = context - ep->urbs;
+       ep->active_urbs &= ~(1 << urb_index);
+       if (unlikely(ep->drain_urbs)) {
+               ep->drain_urbs &= ~(1 << urb_index);
+               wake_up(&ep->drain_wait);
+       }
        spin_unlock(&ep->buffer_lock);
        if (urb->status < 0) {
                int err = snd_usbmidi_urb_error(urb->status);
@@ -291,28 +301,28 @@ static void snd_usbmidi_do_output(struct snd_usb_midi_out_endpoint* ep)
                return;
        }
 
+       urb_index = ep->next_urb;
        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;
+               if (!(ep->active_urbs & (1 << urb_index))) {
+                       urb = ep->urbs[urb_index].urb;
+                       urb->transfer_buffer_length = 0;
+                       ep->umidi->usb_protocol_ops->output(ep, urb);
+                       if (urb->transfer_buffer_length == 0)
                                break;
-                       }
-               if (!urb)
-                       break;
-
-               urb->transfer_buffer_length = 0;
-               ep->umidi->usb_protocol_ops->output(ep, urb);
-               if (urb->transfer_buffer_length == 0)
-                       break;
 
-               dump_urb("sending", urb->transfer_buffer,
-                        urb->transfer_buffer_length);
-               urb->dev = ep->umidi->chip->dev;
-               if (snd_usbmidi_submit_urb(urb, GFP_ATOMIC) < 0)
+                       dump_urb("sending", urb->transfer_buffer,
+                                urb->transfer_buffer_length);
+                       urb->dev = ep->umidi->chip->dev;
+                       if (snd_usbmidi_submit_urb(urb, GFP_ATOMIC) < 0)
+                               break;
+                       ep->active_urbs |= 1 << urb_index;
+               }
+               if (++urb_index >= OUTPUT_URBS)
+                       urb_index = 0;
+               if (urb_index == ep->next_urb)
                        break;
-               ep->active_urbs |= 1 << urb_index;
        }
+       ep->next_urb = urb_index;
        spin_unlock_irqrestore(&ep->buffer_lock, flags);
 }
 
@@ -913,6 +923,35 @@ static void snd_usbmidi_output_trigger(struct snd_rawmidi_substream *substream,
        }
 }
 
+static void snd_usbmidi_output_drain(struct snd_rawmidi_substream *substream)
+{
+       struct usbmidi_out_port* port = substream->runtime->private_data;
+       struct snd_usb_midi_out_endpoint *ep = port->ep;
+       unsigned int drain_urbs;
+       DEFINE_WAIT(wait);
+       long timeout = msecs_to_jiffies(50);
+
+       /*
+        * The substream buffer is empty, but some data might still be in the
+        * currently active URBs, so we have to wait for those to complete.
+        */
+       spin_lock_irq(&ep->buffer_lock);
+       drain_urbs = ep->active_urbs;
+       if (drain_urbs) {
+               ep->drain_urbs |= drain_urbs;
+               do {
+                       prepare_to_wait(&ep->drain_wait, &wait,
+                                       TASK_UNINTERRUPTIBLE);
+                       spin_unlock_irq(&ep->buffer_lock);
+                       timeout = schedule_timeout(timeout);
+                       spin_lock_irq(&ep->buffer_lock);
+                       drain_urbs &= ep->drain_urbs;
+               } while (drain_urbs && timeout);
+               finish_wait(&ep->drain_wait, &wait);
+       }
+       spin_unlock_irq(&ep->buffer_lock);
+}
+
 static int snd_usbmidi_input_open(struct snd_rawmidi_substream *substream)
 {
        return 0;
@@ -937,6 +976,7 @@ static struct snd_rawmidi_ops snd_usbmidi_output_ops = {
        .open = snd_usbmidi_output_open,
        .close = snd_usbmidi_output_close,
        .trigger = snd_usbmidi_output_trigger,
+       .drain = snd_usbmidi_output_drain,
 };
 
 static struct snd_rawmidi_ops snd_usbmidi_input_ops = {
@@ -1103,6 +1143,7 @@ static int snd_usbmidi_out_endpoint_create(struct snd_usb_midi* umidi,
 
        spin_lock_init(&ep->buffer_lock);
        tasklet_init(&ep->tasklet, snd_usbmidi_out_tasklet, (unsigned long)ep);
+       init_waitqueue_head(&ep->drain_wait);
 
        for (i = 0; i < 0x10; ++i)
                if (ep_info->out_cables & (1 << i)) {