ALSA: USB-audio: Add offset parameter to copy_to_urb()

Preparation for adding Zoom R16/24 quirk.
No functional change.

Signed-off-by: Ricard Wanderlof <ricardw@axis.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/usb/pcm.c

@@ -1387,8 +1387,8 @@ static inline void fill_playback_urb_dsd_dop(struct snd_usb_substream *subs,
 		subs->hwptr_done -= runtime->buffer_size * stride;
 }
 
-static void copy_to_urb(struct snd_usb_substream *subs,
-		       struct urb *urb, int stride, unsigned int bytes)
+static void copy_to_urb(struct snd_usb_substream *subs, struct urb *urb,
+			int offset, int stride, unsigned int bytes)
 {
 	struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
 
@@ -1396,12 +1396,12 @@ static void copy_to_urb(struct snd_usb_substream *subs,
 		/* err, the transferred area goes over buffer boundary. */
 		unsigned int bytes1 =
 			runtime->buffer_size * stride - subs->hwptr_done;
-		memcpy(urb->transfer_buffer,
+		memcpy(urb->transfer_buffer + offset,
 		       runtime->dma_area + subs->hwptr_done, bytes1);
-		memcpy(urb->transfer_buffer + bytes1,
+		memcpy(urb->transfer_buffer + offset + bytes1,
 		       runtime->dma_area, bytes - bytes1);
 	} else {
-		memcpy(urb->transfer_buffer,
+		memcpy(urb->transfer_buffer + offset,
 		       runtime->dma_area + subs->hwptr_done, bytes);
 	}
 	subs->hwptr_done += bytes;
@@ -1488,7 +1488,7 @@ static void prepare_playback_urb(struct snd_usb_substream *subs,
 			subs->hwptr_done -= runtime->buffer_size * stride;
 	} else {
 		/* usual PCM */
-		copy_to_urb(subs, urb, stride, bytes);
+		copy_to_urb(subs, urb, 0, stride, bytes);
 	}
 
 	/* update delay with exact number of samples queued */