1 files changed, 171 insertions, 367 deletions

diff --git a/drivers/usb/gadget/uvc_queue.c b/drivers/usb/gadget/uvc_queue.c
index 104ae9c81251..7ce27e35550b 100644
--- a/drivers/usb/gadget/uvc_queue.c
+++ b/drivers/usb/gadget/uvc_queue.c
@@ -10,6 +10,7 @@
  *	(at your option) any later version.
  */
 
+#include <linux/atomic.h>
 #include <linux/kernel.h>
 #include <linux/mm.h>
 #include <linux/list.h>
@@ -18,7 +19,8 @@
 #include <linux/videodev2.h>
 #include <linux/vmalloc.h>
 #include <linux/wait.h>
-#include <linux/atomic.h>
+
+#include <media/videobuf2-vmalloc.h>
 
 #include "uvc.h"
 
@@ -28,330 +30,175 @@
  * Video queues is initialized by uvc_queue_init(). The function performs
  * basic initialization of the uvc_video_queue struct and never fails.
  *
- * Video buffer allocation and freeing are performed by uvc_alloc_buffers and
- * uvc_free_buffers respectively. The former acquires the video queue lock,
- * while the later must be called with the lock held (so that allocation can
- * free previously allocated buffers). Trying to free buffers that are mapped
- * to user space will return -EBUSY.
- *
- * Video buffers are managed using two queues. However, unlike most USB video
- * drivers that use an in queue and an out queue, we use a main queue to hold
- * all queued buffers (both 'empty' and 'done' buffers), and an irq queue to
- * hold empty buffers. This design (copied from video-buf) minimizes locking
- * in interrupt, as only one queue is shared between interrupt and user
- * contexts.
- *
- * Use cases
- * ---------
- *
- * Unless stated otherwise, all operations that modify the irq buffers queue
- * are protected by the irq spinlock.
- *
- * 1. The user queues the buffers, starts streaming and dequeues a buffer.
- *
- *    The buffers are added to the main and irq queues. Both operations are
- *    protected by the queue lock, and the later is protected by the irq
- *    spinlock as well.
- *
- *    The completion handler fetches a buffer from the irq queue and fills it
- *    with video data. If no buffer is available (irq queue empty), the handler
- *    returns immediately.
- *
- *    When the buffer is full, the completion handler removes it from the irq
- *    queue, marks it as ready (UVC_BUF_STATE_DONE) and wakes its wait queue.
- *    At that point, any process waiting on the buffer will be woken up. If a
- *    process tries to dequeue a buffer after it has been marked ready, the
- *    dequeing will succeed immediately.
- *
- * 2. Buffers are queued, user is waiting on a buffer and the device gets
- *    disconnected.
- *
- *    When the device is disconnected, the kernel calls the completion handler
- *    with an appropriate status code. The handler marks all buffers in the
- *    irq queue as being erroneous (UVC_BUF_STATE_ERROR) and wakes them up so
- *    that any process waiting on a buffer gets woken up.
- *
- *    Waking up up the first buffer on the irq list is not enough, as the
- *    process waiting on the buffer might restart the dequeue operation
- *    immediately.
- *
+ * Video buffers are managed by videobuf2. The driver uses a mutex to protect
+ * the videobuf2 queue operations by serializing calls to videobuf2 and a
+ * spinlock to protect the IRQ queue that holds the buffers to be processed by
+ * the driver.
  */
 
-static void
-uvc_queue_init(struct uvc_video_queue *queue, enum v4l2_buf_type type)
-{
-	mutex_init(&queue->mutex);
-	spin_lock_init(&queue->irqlock);
-	INIT_LIST_HEAD(&queue->mainqueue);
-	INIT_LIST_HEAD(&queue->irqqueue);
-	queue->type = type;
-}
-
-/*
- * Free the video buffers.
- *
- * This function must be called with the queue lock held.
+/* -----------------------------------------------------------------------------
+ * videobuf2 queue operations
  */
-static int uvc_free_buffers(struct uvc_video_queue *queue)
+
+static int uvc_queue_setup(struct vb2_queue *vq, const struct v4l2_format *fmt,
+			   unsigned int *nbuffers, unsigned int *nplanes,
+			   unsigned int sizes[], void *alloc_ctxs[])
 {
-	unsigned int i;
+	struct uvc_video_queue *queue = vb2_get_drv_priv(vq);
+	struct uvc_video *video = container_of(queue, struct uvc_video, queue);
 
-	for (i = 0; i < queue->count; ++i) {
-		if (queue->buffer[i].vma_use_count != 0)
-			return -EBUSY;
-	}
+	if (*nbuffers > UVC_MAX_VIDEO_BUFFERS)
+		*nbuffers = UVC_MAX_VIDEO_BUFFERS;
 
-	if (queue->count) {
-		vfree(queue->mem);
-		queue->count = 0;
-	}
+	*nplanes = 1;
+
+	sizes[0] = video->imagesize;
 
 	return 0;
 }
 
-/*
- * Allocate the video buffers.
- *
- * Pages are reserved to make sure they will not be swapped, as they will be
- * filled in the URB completion handler.
- *
- * Buffers will be individually mapped, so they must all be page aligned.
- */
-static int
-uvc_alloc_buffers(struct uvc_video_queue *queue, unsigned int nbuffers,
-		  unsigned int buflength)
+static int uvc_buffer_prepare(struct vb2_buffer *vb)
 {
-	unsigned int bufsize = PAGE_ALIGN(buflength);
-	unsigned int i;
-	void *mem = NULL;
-	int ret;
+	struct uvc_video_queue *queue = vb2_get_drv_priv(vb->vb2_queue);
+	struct uvc_buffer *buf = container_of(vb, struct uvc_buffer, buf);
 
-	if (nbuffers > UVC_MAX_VIDEO_BUFFERS)
-		nbuffers = UVC_MAX_VIDEO_BUFFERS;
+	if (vb->v4l2_buf.type == V4L2_BUF_TYPE_VIDEO_OUTPUT &&
+	    vb2_get_plane_payload(vb, 0) > vb2_plane_size(vb, 0)) {
+		uvc_trace(UVC_TRACE_CAPTURE, "[E] Bytes used out of bounds.\n");
+		return -EINVAL;
+	}
 
-	mutex_lock(&queue->mutex);
+	if (unlikely(queue->flags & UVC_QUEUE_DISCONNECTED))
+		return -ENODEV;
 
-	if ((ret = uvc_free_buffers(queue)) < 0)
-		goto done;
+	buf->state = UVC_BUF_STATE_QUEUED;
+	buf->mem = vb2_plane_vaddr(vb, 0);
+	buf->length = vb2_plane_size(vb, 0);
+	if (vb->v4l2_buf.type == V4L2_BUF_TYPE_VIDEO_CAPTURE)
+		buf->bytesused = 0;
+	else
+		buf->bytesused = vb2_get_plane_payload(vb, 0);
 
-	/* Bail out if no buffers should be allocated. */
-	if (nbuffers == 0)
-		goto done;
+	return 0;
+}
 
-	/* Decrement the number of buffers until allocation succeeds. */
-	for (; nbuffers > 0; --nbuffers) {
-		mem = vmalloc_32(nbuffers * bufsize);
-		if (mem != NULL)
-			break;
-	}
+static void uvc_buffer_queue(struct vb2_buffer *vb)
+{
+	struct uvc_video_queue *queue = vb2_get_drv_priv(vb->vb2_queue);
+	struct uvc_buffer *buf = container_of(vb, struct uvc_buffer, buf);
+	unsigned long flags;
 
-	if (mem == NULL) {
-		ret = -ENOMEM;
-		goto done;
-	}
+	spin_lock_irqsave(&queue->irqlock, flags);
 
-	for (i = 0; i < nbuffers; ++i) {
-		memset(&queue->buffer[i], 0, sizeof queue->buffer[i]);
-		queue->buffer[i].buf.index = i;
-		queue->buffer[i].buf.m.offset = i * bufsize;
-		queue->buffer[i].buf.length = buflength;
-		queue->buffer[i].buf.type = queue->type;
-		queue->buffer[i].buf.sequence = 0;
-		queue->buffer[i].buf.field = V4L2_FIELD_NONE;
-		queue->buffer[i].buf.memory = V4L2_MEMORY_MMAP;
-		queue->buffer[i].buf.flags = 0;
-		init_waitqueue_head(&queue->buffer[i].wait);
+	if (likely(!(queue->flags & UVC_QUEUE_DISCONNECTED))) {
+		list_add_tail(&buf->queue, &queue->irqqueue);
+	} else {
+		/* If the device is disconnected return the buffer to userspace
+		 * directly. The next QBUF call will fail with -ENODEV.
+		 */
+		buf->state = UVC_BUF_STATE_ERROR;
+		vb2_buffer_done(&buf->buf, VB2_BUF_STATE_ERROR);
 	}
 
-	queue->mem = mem;
-	queue->count = nbuffers;
-	queue->buf_size = bufsize;
-	ret = nbuffers;
-
-done:
-	mutex_unlock(&queue->mutex);
-	return ret;
+	spin_unlock_irqrestore(&queue->irqlock, flags);
 }
 
-static void __uvc_query_buffer(struct uvc_buffer *buf,
-		struct v4l2_buffer *v4l2_buf)
-{
-	memcpy(v4l2_buf, &buf->buf, sizeof *v4l2_buf);
-
-	if (buf->vma_use_count)
-		v4l2_buf->flags |= V4L2_BUF_FLAG_MAPPED;
-
-	switch (buf->state) {
-	case UVC_BUF_STATE_ERROR:
-	case UVC_BUF_STATE_DONE:
-		v4l2_buf->flags |= V4L2_BUF_FLAG_DONE;
-		break;
-	case UVC_BUF_STATE_QUEUED:
-	case UVC_BUF_STATE_ACTIVE:
-		v4l2_buf->flags |= V4L2_BUF_FLAG_QUEUED;
-		break;
-	case UVC_BUF_STATE_IDLE:
-	default:
-		break;
-	}
-}
+static struct vb2_ops uvc_queue_qops = {
+	.queue_setup = uvc_queue_setup,
+	.buf_prepare = uvc_buffer_prepare,
+	.buf_queue = uvc_buffer_queue,
+};
 
-static int
-uvc_query_buffer(struct uvc_video_queue *queue, struct v4l2_buffer *v4l2_buf)
+static int uvc_queue_init(struct uvc_video_queue *queue,
+			  enum v4l2_buf_type type)
 {
-	int ret = 0;
+	int ret;
 
-	mutex_lock(&queue->mutex);
-	if (v4l2_buf->index >= queue->count) {
-		ret = -EINVAL;
-		goto done;
-	}
+	queue->queue.type = type;
+	queue->queue.io_modes = VB2_MMAP | VB2_USERPTR;
+	queue->queue.drv_priv = queue;
+	queue->queue.buf_struct_size = sizeof(struct uvc_buffer);
+	queue->queue.ops = &uvc_queue_qops;
+	queue->queue.mem_ops = &vb2_vmalloc_memops;
+	ret = vb2_queue_init(&queue->queue);
+	if (ret)
+		return ret;
+
+	mutex_init(&queue->mutex);
+	spin_lock_init(&queue->irqlock);
+	INIT_LIST_HEAD(&queue->irqqueue);
+	queue->flags = 0;
 
-	__uvc_query_buffer(&queue->buffer[v4l2_buf->index], v4l2_buf);
+	return 0;
+}
 
-done:
+/*
+ * Free the video buffers.
+ */
+static void uvc_free_buffers(struct uvc_video_queue *queue)
+{
+	mutex_lock(&queue->mutex);
+	vb2_queue_release(&queue->queue);
 	mutex_unlock(&queue->mutex);
-	return ret;
 }
 
 /*
- * Queue a video buffer. Attempting to queue a buffer that has already been
- * queued will return -EINVAL.
+ * Allocate the video buffers.
  */
-static int
-uvc_queue_buffer(struct uvc_video_queue *queue, struct v4l2_buffer *v4l2_buf)
+static int uvc_alloc_buffers(struct uvc_video_queue *queue,
+			     struct v4l2_requestbuffers *rb)
 {
-	struct uvc_buffer *buf;
-	unsigned long flags;
-	int ret = 0;
+	int ret;
 
-	uvc_trace(UVC_TRACE_CAPTURE, "Queuing buffer %u.\n", v4l2_buf->index);
+	mutex_lock(&queue->mutex);
+	ret = vb2_reqbufs(&queue->queue, rb);
+	mutex_unlock(&queue->mutex);
 
-	if (v4l2_buf->type != queue->type ||
-	    v4l2_buf->memory != V4L2_MEMORY_MMAP) {
-		uvc_trace(UVC_TRACE_CAPTURE, "[E] Invalid buffer type (%u) "
-			"and/or memory (%u).\n", v4l2_buf->type,
-			v4l2_buf->memory);
-		return -EINVAL;
-	}
+	return ret ? ret : rb->count;
+}
 
-	mutex_lock(&queue->mutex);
-	if (v4l2_buf->index >= queue->count) {
-		uvc_trace(UVC_TRACE_CAPTURE, "[E] Out of range index.\n");
-		ret = -EINVAL;
-		goto done;
-	}
+static int uvc_query_buffer(struct uvc_video_queue *queue,
+			    struct v4l2_buffer *buf)
+{
+	int ret;
 
-	buf = &queue->buffer[v4l2_buf->index];
-	if (buf->state != UVC_BUF_STATE_IDLE) {
-		uvc_trace(UVC_TRACE_CAPTURE, "[E] Invalid buffer state "
-			"(%u).\n", buf->state);
-		ret = -EINVAL;
-		goto done;
-	}
+	mutex_lock(&queue->mutex);
+	ret = vb2_querybuf(&queue->queue, buf);
+	mutex_unlock(&queue->mutex);
 
-	if (v4l2_buf->type == V4L2_BUF_TYPE_VIDEO_OUTPUT &&
-	    v4l2_buf->bytesused > buf->buf.length) {
-		uvc_trace(UVC_TRACE_CAPTURE, "[E] Bytes used out of bounds.\n");
-		ret = -EINVAL;
-		goto done;
-	}
+	return ret;
+}
 
-	if (v4l2_buf->type == V4L2_BUF_TYPE_VIDEO_CAPTURE)
-		buf->buf.bytesused = 0;
-	else
-		buf->buf.bytesused = v4l2_buf->bytesused;
+static int uvc_queue_buffer(struct uvc_video_queue *queue,
+			    struct v4l2_buffer *buf)
+{
+	unsigned long flags;
+	int ret;
 
+	mutex_lock(&queue->mutex);
+	ret = vb2_qbuf(&queue->queue, buf);
 	spin_lock_irqsave(&queue->irqlock, flags);
-	if (queue->flags & UVC_QUEUE_DISCONNECTED) {
-		spin_unlock_irqrestore(&queue->irqlock, flags);
-		ret = -ENODEV;
-		goto done;
-	}
-	buf->state = UVC_BUF_STATE_QUEUED;
-
 	ret = (queue->flags & UVC_QUEUE_PAUSED) != 0;
 	queue->flags &= ~UVC_QUEUE_PAUSED;
-
-	list_add_tail(&buf->stream, &queue->mainqueue);
-	list_add_tail(&buf->queue, &queue->irqqueue);
 	spin_unlock_irqrestore(&queue->irqlock, flags);
-
-done:
 	mutex_unlock(&queue->mutex);
-	return ret;
-}
 
-static int uvc_queue_waiton(struct uvc_buffer *buf, int nonblocking)
-{
-	if (nonblocking) {
-		return (buf->state != UVC_BUF_STATE_QUEUED &&
-			buf->state != UVC_BUF_STATE_ACTIVE)
-			? 0 : -EAGAIN;
-	}
-
-	return wait_event_interruptible(buf->wait,
-		buf->state != UVC_BUF_STATE_QUEUED &&
-		buf->state != UVC_BUF_STATE_ACTIVE);
+	return ret;
 }
 
 /*
  * Dequeue a video buffer. If nonblocking is false, block until a buffer is
  * available.
  */
-static int
-uvc_dequeue_buffer(struct uvc_video_queue *queue, struct v4l2_buffer *v4l2_buf,
-		   int nonblocking)
+static int uvc_dequeue_buffer(struct uvc_video_queue *queue,
+			      struct v4l2_buffer *buf, int nonblocking)
 {
-	struct uvc_buffer *buf;
-	int ret = 0;
-
-	if (v4l2_buf->type != queue->type ||
-	    v4l2_buf->memory != V4L2_MEMORY_MMAP) {
-		uvc_trace(UVC_TRACE_CAPTURE, "[E] Invalid buffer type (%u) "
-			"and/or memory (%u).\n", v4l2_buf->type,
-			v4l2_buf->memory);
-		return -EINVAL;
-	}
+	int ret;
 
 	mutex_lock(&queue->mutex);
-	if (list_empty(&queue->mainqueue)) {
-		uvc_trace(UVC_TRACE_CAPTURE, "[E] Empty buffer queue.\n");
-		ret = -EINVAL;
-		goto done;
-	}
-
-	buf = list_first_entry(&queue->mainqueue, struct uvc_buffer, stream);
-	if ((ret = uvc_queue_waiton(buf, nonblocking)) < 0)
-		goto done;
-
-	uvc_trace(UVC_TRACE_CAPTURE, "Dequeuing buffer %u (%u, %u bytes).\n",
-		buf->buf.index, buf->state, buf->buf.bytesused);
-
-	switch (buf->state) {
-	case UVC_BUF_STATE_ERROR:
-		uvc_trace(UVC_TRACE_CAPTURE, "[W] Corrupted data "
-			"(transmission error).\n");
-		ret = -EIO;
-	case UVC_BUF_STATE_DONE:
-		buf->state = UVC_BUF_STATE_IDLE;
-		break;
-
-	case UVC_BUF_STATE_IDLE:
-	case UVC_BUF_STATE_QUEUED:
-	case UVC_BUF_STATE_ACTIVE:
-	default:
-		uvc_trace(UVC_TRACE_CAPTURE, "[E] Invalid buffer state %u "
-			"(driver bug?).\n", buf->state);
-		ret = -EINVAL;
-		goto done;
-	}
-
-	list_del(&buf->stream);
-	__uvc_query_buffer(buf, v4l2_buf);
-
-done:
+	ret = vb2_dqbuf(&queue->queue, buf, nonblocking);
 	mutex_unlock(&queue->mutex);
+
 	return ret;
 }
 
@@ -361,105 +208,47 @@ done:
  * This function implements video queue polling and is intended to be used by
  * the device poll handler.
  */
-static unsigned int
-uvc_queue_poll(struct uvc_video_queue *queue, struct file *file,
-	       poll_table *wait)
+static unsigned int uvc_queue_poll(struct uvc_video_queue *queue,
+				   struct file *file, poll_table *wait)
 {
-	struct uvc_buffer *buf;
-	unsigned int mask = 0;
+	unsigned int ret;
 
 	mutex_lock(&queue->mutex);
-	if (list_empty(&queue->mainqueue))
-		goto done;
-
-	buf = list_first_entry(&queue->mainqueue, struct uvc_buffer, stream);
-
-	poll_wait(file, &buf->wait, wait);
-	if (buf->state == UVC_BUF_STATE_DONE ||
-	    buf->state == UVC_BUF_STATE_ERROR)
-		mask |= POLLOUT | POLLWRNORM;
-
-done:
+	ret = vb2_poll(&queue->queue, file, wait);
 	mutex_unlock(&queue->mutex);
-	return mask;
-}
 
-/*
- * VMA operations.
- */
-static void uvc_vm_open(struct vm_area_struct *vma)
-{
-	struct uvc_buffer *buffer = vma->vm_private_data;
-	buffer->vma_use_count++;
+	return ret;
 }
 
-static void uvc_vm_close(struct vm_area_struct *vma)
+static int uvc_queue_mmap(struct uvc_video_queue *queue,
+			  struct vm_area_struct *vma)
 {
-	struct uvc_buffer *buffer = vma->vm_private_data;
-	buffer->vma_use_count--;
-}
+	int ret;
 
-static struct vm_operations_struct uvc_vm_ops = {
-	.open		= uvc_vm_open,
-	.close		= uvc_vm_close,
-};
+	mutex_lock(&queue->mutex);
+	ret = vb2_mmap(&queue->queue, vma);
+	mutex_unlock(&queue->mutex);
+
+	return ret;
+}
 
+#ifndef CONFIG_MMU
 /*
- * Memory-map a buffer.
+ * Get unmapped area.
  *
- * This function implements video buffer memory mapping and is intended to be
- * used by the device mmap handler.
+ * NO-MMU arch need this function to make mmap() work correctly.
  */
-static int
-uvc_queue_mmap(struct uvc_video_queue *queue, struct vm_area_struct *vma)
+static unsigned long uvc_queue_get_unmapped_area(struct uvc_video_queue *queue,
+		unsigned long pgoff)
 {
-	struct uvc_buffer *uninitialized_var(buffer);
-	struct page *page;
-	unsigned long addr, start, size;
-	unsigned int i;
-	int ret = 0;
-
-	start = vma->vm_start;
-	size = vma->vm_end - vma->vm_start;
+	unsigned long ret;
 
 	mutex_lock(&queue->mutex);
-
-	for (i = 0; i < queue->count; ++i) {
-		buffer = &queue->buffer[i];
-		if ((buffer->buf.m.offset >> PAGE_SHIFT) == vma->vm_pgoff)
-			break;
-	}
-
-	if (i == queue->count || size != queue->buf_size) {
-		ret = -EINVAL;
-		goto done;
-	}
-
-	/*
-	 * VM_IO marks the area as being an mmaped region for I/O to a
-	 * device. It also prevents the region from being core dumped.
-	 */
-	vma->vm_flags |= VM_IO;
-
-	addr = (unsigned long)queue->mem + buffer->buf.m.offset;
-	while (size > 0) {
-		page = vmalloc_to_page((void *)addr);
-		if ((ret = vm_insert_page(vma, start, page)) < 0)
-			goto done;
-
-		start += PAGE_SIZE;
-		addr += PAGE_SIZE;
-		size -= PAGE_SIZE;
-	}
-
-	vma->vm_ops = &uvc_vm_ops;
-	vma->vm_private_data = buffer;
-	uvc_vm_open(vma);
-
-done:
+	ret = vb2_get_unmapped_area(&queue->queue, 0, 0, pgoff, 0);
 	mutex_unlock(&queue->mutex);
 	return ret;
 }
+#endif
 
 /*
  * Cancel the video buffers queue.
@@ -484,7 +273,7 @@ static void uvc_queue_cancel(struct uvc_video_queue *queue, int disconnect)
 				       queue);
 		list_del(&buf->queue);
 		buf->state = UVC_BUF_STATE_ERROR;
-		wake_up(&buf->wait);
+		vb2_buffer_done(&buf->buf, VB2_BUF_STATE_ERROR);
 	}
 	/* This must be protected by the irqlock spinlock to avoid race
 	 * conditions between uvc_queue_buffer and the disconnection event that
@@ -516,26 +305,33 @@ static void uvc_queue_cancel(struct uvc_video_queue *queue, int disconnect)
  */
 static int uvc_queue_enable(struct uvc_video_queue *queue, int enable)
 {
-	unsigned int i;
+	unsigned long flags;
 	int ret = 0;
 
 	mutex_lock(&queue->mutex);
 	if (enable) {
-		if (uvc_queue_streaming(queue)) {
-			ret = -EBUSY;
+		ret = vb2_streamon(&queue->queue, queue->queue.type);
+		if (ret < 0)
 			goto done;
-		}
+
 		queue->sequence = 0;
-		queue->flags |= UVC_QUEUE_STREAMING;
 		queue->buf_used = 0;
 	} else {
-		uvc_queue_cancel(queue, 0);
-		INIT_LIST_HEAD(&queue->mainqueue);
+		ret = vb2_streamoff(&queue->queue, queue->queue.type);
+		if (ret < 0)
+			goto done;
 
-		for (i = 0; i < queue->count; ++i)
-			queue->buffer[i].state = UVC_BUF_STATE_IDLE;
+		spin_lock_irqsave(&queue->irqlock, flags);
+		INIT_LIST_HEAD(&queue->irqqueue);
 
-		queue->flags &= ~UVC_QUEUE_STREAMING;
+		/*
+		 * FIXME: We need to clear the DISCONNECTED flag to ensure that
+		 * applications will be able to queue buffers for the next
+		 * streaming run. However, clearing it here doesn't guarantee
+		 * that the device will be reconnected in the meantime.
+		 */
+		queue->flags &= ~UVC_QUEUE_DISCONNECTED;
+		spin_unlock_irqrestore(&queue->irqlock, flags);
 	}
 
 done:
@@ -544,15 +340,15 @@ done:
 }
 
 /* called with &queue_irqlock held.. */
-static struct uvc_buffer *
-uvc_queue_next_buffer(struct uvc_video_queue *queue, struct uvc_buffer *buf)
+static struct uvc_buffer *uvc_queue_next_buffer(struct uvc_video_queue *queue,
+						struct uvc_buffer *buf)
 {
 	struct uvc_buffer *nextbuf;
 
 	if ((queue->flags & UVC_QUEUE_DROP_INCOMPLETE) &&
-	    buf->buf.length != buf->buf.bytesused) {
+	     buf->length != buf->bytesused) {
 		buf->state = UVC_BUF_STATE_QUEUED;
-		buf->buf.bytesused = 0;
+		vb2_set_plane_payload(&buf->buf, 0, 0);
 		return buf;
 	}
 
@@ -563,10 +359,18 @@ uvc_queue_next_buffer(struct uvc_video_queue *queue, struct uvc_buffer *buf)
 	else
 		nextbuf = NULL;
 
-	buf->buf.sequence = queue->sequence++;
-	do_gettimeofday(&buf->buf.timestamp);
+	/*
+	 * FIXME: with videobuf2, the sequence number or timestamp fields
+	 * are valid only for video capture devices and the UVC gadget usually
+	 * is a video output device. Keeping these until the specs are clear on
+	 * this aspect.
+	 */
+	buf->buf.v4l2_buf.sequence = queue->sequence++;
+	do_gettimeofday(&buf->buf.v4l2_buf.timestamp);
+
+	vb2_set_plane_payload(&buf->buf, 0, buf->bytesused);
+	vb2_buffer_done(&buf->buf, VB2_BUF_STATE_DONE);
 
-	wake_up(&buf->wait);
 	return nextbuf;
 }