1 files changed, 836 insertions, 90 deletions

diff --git a/drivers/media/v4l2-core/videobuf2-core.c b/drivers/media/v4l2-core/videobuf2-core.c
index 33bdd81065e8..c5d49d7a0d76 100644
--- a/drivers/media/v4l2-core/videobuf2-core.c
+++ b/drivers/media/v4l2-core/videobuf2-core.c
@@ -28,11 +28,161 @@
 
 #include <trace/events/vb2.h>
 
-#include "videobuf2-internal.h"
+static int debug;
+module_param(debug, int, 0644);
 
-int vb2_debug;
-EXPORT_SYMBOL_GPL(vb2_debug);
-module_param_named(debug, vb2_debug, int, 0644);
+#define dprintk(level, fmt, arg...)					      \
+	do {								      \
+		if (debug >= level)					      \
+			pr_info("vb2-core: %s: " fmt, __func__, ## arg); \
+	} while (0)
+
+#ifdef CONFIG_VIDEO_ADV_DEBUG
+
+/*
+ * If advanced debugging is on, then count how often each op is called
+ * successfully, which can either be per-buffer or per-queue.
+ *
+ * This makes it easy to check that the 'init' and 'cleanup'
+ * (and variations thereof) stay balanced.
+ */
+
+#define log_memop(vb, op)						\
+	dprintk(2, "call_memop(%p, %d, %s)%s\n",			\
+		(vb)->vb2_queue, (vb)->index, #op,			\
+		(vb)->vb2_queue->mem_ops->op ? "" : " (nop)")
+
+#define call_memop(vb, op, args...)					\
+({									\
+	struct vb2_queue *_q = (vb)->vb2_queue;				\
+	int err;							\
+									\
+	log_memop(vb, op);						\
+	err = _q->mem_ops->op ? _q->mem_ops->op(args) : 0;		\
+	if (!err)							\
+		(vb)->cnt_mem_ ## op++;					\
+	err;								\
+})
+
+#define call_ptr_memop(vb, op, args...)					\
+({									\
+	struct vb2_queue *_q = (vb)->vb2_queue;				\
+	void *ptr;							\
+									\
+	log_memop(vb, op);						\
+	ptr = _q->mem_ops->op ? _q->mem_ops->op(args) : NULL;		\
+	if (!IS_ERR_OR_NULL(ptr))					\
+		(vb)->cnt_mem_ ## op++;					\
+	ptr;								\
+})
+
+#define call_void_memop(vb, op, args...)				\
+({									\
+	struct vb2_queue *_q = (vb)->vb2_queue;				\
+									\
+	log_memop(vb, op);						\
+	if (_q->mem_ops->op)						\
+		_q->mem_ops->op(args);					\
+	(vb)->cnt_mem_ ## op++;						\
+})
+
+#define log_qop(q, op)							\
+	dprintk(2, "call_qop(%p, %s)%s\n", q, #op,			\
+		(q)->ops->op ? "" : " (nop)")
+
+#define call_qop(q, op, args...)					\
+({									\
+	int err;							\
+									\
+	log_qop(q, op);							\
+	err = (q)->ops->op ? (q)->ops->op(args) : 0;			\
+	if (!err)							\
+		(q)->cnt_ ## op++;					\
+	err;								\
+})
+
+#define call_void_qop(q, op, args...)					\
+({									\
+	log_qop(q, op);							\
+	if ((q)->ops->op)						\
+		(q)->ops->op(args);					\
+	(q)->cnt_ ## op++;						\
+})
+
+#define log_vb_qop(vb, op, args...)					\
+	dprintk(2, "call_vb_qop(%p, %d, %s)%s\n",			\
+		(vb)->vb2_queue, (vb)->index, #op,			\
+		(vb)->vb2_queue->ops->op ? "" : " (nop)")
+
+#define call_vb_qop(vb, op, args...)					\
+({									\
+	int err;							\
+									\
+	log_vb_qop(vb, op);						\
+	err = (vb)->vb2_queue->ops->op ?				\
+		(vb)->vb2_queue->ops->op(args) : 0;			\
+	if (!err)							\
+		(vb)->cnt_ ## op++;					\
+	err;								\
+})
+
+#define call_void_vb_qop(vb, op, args...)				\
+({									\
+	log_vb_qop(vb, op);						\
+	if ((vb)->vb2_queue->ops->op)					\
+		(vb)->vb2_queue->ops->op(args);				\
+	(vb)->cnt_ ## op++;						\
+})
+
+#else
+
+#define call_memop(vb, op, args...)					\
+	((vb)->vb2_queue->mem_ops->op ?					\
+		(vb)->vb2_queue->mem_ops->op(args) : 0)
+
+#define call_ptr_memop(vb, op, args...)					\
+	((vb)->vb2_queue->mem_ops->op ?					\
+		(vb)->vb2_queue->mem_ops->op(args) : NULL)
+
+#define call_void_memop(vb, op, args...)				\
+	do {								\
+		if ((vb)->vb2_queue->mem_ops->op)			\
+			(vb)->vb2_queue->mem_ops->op(args);		\
+	} while (0)
+
+#define call_qop(q, op, args...)					\
+	((q)->ops->op ? (q)->ops->op(args) : 0)
+
+#define call_void_qop(q, op, args...)					\
+	do {								\
+		if ((q)->ops->op)					\
+			(q)->ops->op(args);				\
+	} while (0)
+
+#define call_vb_qop(vb, op, args...)					\
+	((vb)->vb2_queue->ops->op ? (vb)->vb2_queue->ops->op(args) : 0)
+
+#define call_void_vb_qop(vb, op, args...)				\
+	do {								\
+		if ((vb)->vb2_queue->ops->op)				\
+			(vb)->vb2_queue->ops->op(args);			\
+	} while (0)
+
+#endif
+
+#define call_bufop(q, op, args...)					\
+({									\
+	int ret = 0;							\
+	if (q && q->buf_ops && q->buf_ops->op)				\
+		ret = q->buf_ops->op(args);				\
+	ret;								\
+})
+
+#define call_void_bufop(q, op, args...)					\
+({									\
+	if (q && q->buf_ops && q->buf_ops->op)				\
+		q->buf_ops->op(args);					\
+})
 
 static void __vb2_queue_cancel(struct vb2_queue *q);
 static void __enqueue_in_driver(struct vb2_buffer *vb);
@@ -53,7 +203,7 @@ static int __vb2_buf_mem_alloc(struct vb2_buffer *vb)
 	 * NOTE: mmapped areas should be page aligned
 	 */
 	for (plane = 0; plane < vb->num_planes; ++plane) {
-		unsigned long size = PAGE_ALIGN(q->plane_sizes[plane]);
+		unsigned long size = PAGE_ALIGN(vb->planes[plane].length);
 
 		mem_priv = call_ptr_memop(vb, alloc, q->alloc_ctx[plane],
 				      size, dma_dir, q->gfp_flags);
@@ -62,7 +212,6 @@ static int __vb2_buf_mem_alloc(struct vb2_buffer *vb)
 
 		/* Associate allocator private data with this plane */
 		vb->planes[plane].mem_priv = mem_priv;
-		vb->planes[plane].length = q->plane_sizes[plane];
 	}
 
 	return 0;
@@ -137,57 +286,30 @@ static void __vb2_buf_dmabuf_put(struct vb2_buffer *vb)
 }
 
 /**
- * __setup_lengths() - setup initial lengths for every plane in
- * every buffer on the queue
- */
-static void __setup_lengths(struct vb2_queue *q, unsigned int n)
-{
-	unsigned int buffer, plane;
-	struct vb2_buffer *vb;
-
-	for (buffer = q->num_buffers; buffer < q->num_buffers + n; ++buffer) {
-		vb = q->bufs[buffer];
-		if (!vb)
-			continue;
-
-		for (plane = 0; plane < vb->num_planes; ++plane)
-			vb->planes[plane].length = q->plane_sizes[plane];
-	}
-}
-
-/**
  * __setup_offsets() - setup unique offsets ("cookies") for every plane in
- * every buffer on the queue
+ * the buffer.
  */
-static void __setup_offsets(struct vb2_queue *q, unsigned int n)
+static void __setup_offsets(struct vb2_buffer *vb)
 {
-	unsigned int buffer, plane;
-	struct vb2_buffer *vb;
-	unsigned long off;
+	struct vb2_queue *q = vb->vb2_queue;
+	unsigned int plane;
+	unsigned long off = 0;
+
+	if (vb->index) {
+		struct vb2_buffer *prev = q->bufs[vb->index - 1];
+		struct vb2_plane *p = &prev->planes[prev->num_planes - 1];
 
-	if (q->num_buffers) {
-		struct vb2_plane *p;
-		vb = q->bufs[q->num_buffers - 1];
-		p = &vb->planes[vb->num_planes - 1];
 		off = PAGE_ALIGN(p->m.offset + p->length);
-	} else {
-		off = 0;
 	}
 
-	for (buffer = q->num_buffers; buffer < q->num_buffers + n; ++buffer) {
-		vb = q->bufs[buffer];
-		if (!vb)
-			continue;
-
-		for (plane = 0; plane < vb->num_planes; ++plane) {
-			vb->planes[plane].m.offset = off;
+	for (plane = 0; plane < vb->num_planes; ++plane) {
+		vb->planes[plane].m.offset = off;
 
-			dprintk(3, "buffer %d, plane %d offset 0x%08lx\n",
-					buffer, plane, off);
+		dprintk(3, "buffer %d, plane %d offset 0x%08lx\n",
+				vb->index, plane, off);
 
-			off += vb->planes[plane].length;
-			off = PAGE_ALIGN(off);
-		}
+		off += vb->planes[plane].length;
+		off = PAGE_ALIGN(off);
 	}
 }
 
@@ -199,9 +321,10 @@ static void __setup_offsets(struct vb2_queue *q, unsigned int n)
  * Returns the number of buffers successfully allocated.
  */
 static int __vb2_queue_alloc(struct vb2_queue *q, enum vb2_memory memory,
-			     unsigned int num_buffers, unsigned int num_planes)
+			     unsigned int num_buffers, unsigned int num_planes,
+			     const unsigned plane_sizes[VB2_MAX_PLANES])
 {
-	unsigned int buffer;
+	unsigned int buffer, plane;
 	struct vb2_buffer *vb;
 	int ret;
 
@@ -219,6 +342,11 @@ static int __vb2_queue_alloc(struct vb2_queue *q, enum vb2_memory memory,
 		vb->index = q->num_buffers + buffer;
 		vb->type = q->type;
 		vb->memory = memory;
+		for (plane = 0; plane < num_planes; ++plane) {
+			vb->planes[plane].length = plane_sizes[plane];
+			vb->planes[plane].min_length = plane_sizes[plane];
+		}
+		q->bufs[vb->index] = vb;
 
 		/* Allocate video buffer memory for the MMAP type */
 		if (memory == VB2_MEMORY_MMAP) {
@@ -226,9 +354,11 @@ static int __vb2_queue_alloc(struct vb2_queue *q, enum vb2_memory memory,
 			if (ret) {
 				dprintk(1, "failed allocating memory for "
 						"buffer %d\n", buffer);
+				q->bufs[vb->index] = NULL;
 				kfree(vb);
 				break;
 			}
+			__setup_offsets(vb);
 			/*
 			 * Call the driver-provided buffer initialization
 			 * callback, if given. An error in initialization
@@ -239,18 +369,13 @@ static int __vb2_queue_alloc(struct vb2_queue *q, enum vb2_memory memory,
 				dprintk(1, "buffer %d %p initialization"
 					" failed\n", buffer, vb);
 				__vb2_buf_mem_free(vb);
+				q->bufs[vb->index] = NULL;
 				kfree(vb);
 				break;
 			}
 		}
-
-		q->bufs[q->num_buffers + buffer] = vb;
 	}
 
-	__setup_lengths(q, buffer);
-	if (memory == VB2_MEMORY_MMAP)
-		__setup_offsets(q, buffer);
-
 	dprintk(1, "allocated %d buffers, %d plane(s) each\n",
 			buffer, num_planes);
 
@@ -330,7 +455,7 @@ static int __vb2_queue_free(struct vb2_queue *q, unsigned int buffers)
 		bool unbalanced = q->cnt_start_streaming != q->cnt_stop_streaming ||
 				  q->cnt_wait_prepare != q->cnt_wait_finish;
 
-		if (unbalanced || vb2_debug) {
+		if (unbalanced || debug) {
 			pr_info("vb2: counters for queue %p:%s\n", q,
 				unbalanced ? " UNBALANCED!" : "");
 			pr_info("vb2:     setup: %u start_streaming: %u stop_streaming: %u\n",
@@ -356,7 +481,7 @@ static int __vb2_queue_free(struct vb2_queue *q, unsigned int buffers)
 				  vb->cnt_buf_prepare != vb->cnt_buf_finish ||
 				  vb->cnt_buf_init != vb->cnt_buf_cleanup;
 
-		if (unbalanced || vb2_debug) {
+		if (unbalanced || debug) {
 			pr_info("vb2:   counters for queue %p, buffer %d:%s\n",
 				q, buffer, unbalanced ? " UNBALANCED!" : "");
 			pr_info("vb2:     buf_init: %u buf_cleanup: %u buf_prepare: %u buf_finish: %u\n",
@@ -442,13 +567,10 @@ static bool __buffers_in_use(struct vb2_queue *q)
  * Should be called from vidioc_querybuf ioctl handler in driver.
  * The passed buffer should have been verified.
  * This function fills the relevant information for the userspace.
- *
- * The return values from this function are intended to be directly returned
- * from vidioc_querybuf handler in driver.
  */
-int vb2_core_querybuf(struct vb2_queue *q, unsigned int index, void *pb)
+void vb2_core_querybuf(struct vb2_queue *q, unsigned int index, void *pb)
 {
-	return call_bufop(q, fill_user_buffer, q->bufs[index], pb);
+	call_void_bufop(q, fill_user_buffer, q->bufs[index], pb);
 }
 EXPORT_SYMBOL_GPL(vb2_core_querybuf);
 
@@ -570,6 +692,7 @@ int vb2_core_reqbufs(struct vb2_queue *q, enum vb2_memory memory,
 		unsigned int *count)
 {
 	unsigned int num_buffers, allocated_buffers, num_planes = 0;
+	unsigned plane_sizes[VB2_MAX_PLANES] = { };
 	int ret;
 
 	if (q->streaming) {
@@ -613,7 +736,6 @@ int vb2_core_reqbufs(struct vb2_queue *q, enum vb2_memory memory,
 	 */
 	num_buffers = min_t(unsigned int, *count, VB2_MAX_FRAME);
 	num_buffers = max_t(unsigned int, num_buffers, q->min_buffers_needed);
-	memset(q->plane_sizes, 0, sizeof(q->plane_sizes));
 	memset(q->alloc_ctx, 0, sizeof(q->alloc_ctx));
 	q->memory = memory;
 
@@ -621,14 +743,14 @@ int vb2_core_reqbufs(struct vb2_queue *q, enum vb2_memory memory,
 	 * Ask the driver how many buffers and planes per buffer it requires.
 	 * Driver also sets the size and allocator context for each plane.
 	 */
-	ret = call_qop(q, queue_setup, q, NULL, &num_buffers, &num_planes,
-		       q->plane_sizes, q->alloc_ctx);
+	ret = call_qop(q, queue_setup, q, &num_buffers, &num_planes,
+		       plane_sizes, q->alloc_ctx);
 	if (ret)
 		return ret;
 
 	/* Finally, allocate buffers and video memory */
 	allocated_buffers =
-		__vb2_queue_alloc(q, memory, num_buffers, num_planes);
+		__vb2_queue_alloc(q, memory, num_buffers, num_planes, plane_sizes);
 	if (allocated_buffers == 0) {
 		dprintk(1, "memory allocation failed\n");
 		return -ENOMEM;
@@ -646,9 +768,16 @@ int vb2_core_reqbufs(struct vb2_queue *q, enum vb2_memory memory,
 	 */
 	if (!ret && allocated_buffers < num_buffers) {
 		num_buffers = allocated_buffers;
+		/*
+		 * num_planes is set by the previous queue_setup(), but since it
+		 * signals to queue_setup() whether it is called from create_bufs()
+		 * vs reqbufs() we zero it here to signal that queue_setup() is
+		 * called for the reqbufs() case.
+		 */
+		num_planes = 0;
 
-		ret = call_qop(q, queue_setup, q, NULL, &num_buffers,
-			       &num_planes, q->plane_sizes, q->alloc_ctx);
+		ret = call_qop(q, queue_setup, q, &num_buffers,
+			       &num_planes, plane_sizes, q->alloc_ctx);
 
 		if (!ret && allocated_buffers < num_buffers)
 			ret = -ENOMEM;
@@ -701,9 +830,11 @@ EXPORT_SYMBOL_GPL(vb2_core_reqbufs);
  * from vidioc_create_bufs handler in driver.
  */
 int vb2_core_create_bufs(struct vb2_queue *q, enum vb2_memory memory,
-		unsigned int *count, const void *parg)
+		unsigned int *count, unsigned requested_planes,
+		const unsigned requested_sizes[])
 {
 	unsigned int num_planes = 0, num_buffers, allocated_buffers;
+	unsigned plane_sizes[VB2_MAX_PLANES] = { };
 	int ret;
 
 	if (q->num_buffers == VB2_MAX_FRAME) {
@@ -712,7 +843,6 @@ int vb2_core_create_bufs(struct vb2_queue *q, enum vb2_memory memory,
 	}
 
 	if (!q->num_buffers) {
-		memset(q->plane_sizes, 0, sizeof(q->plane_sizes));
 		memset(q->alloc_ctx, 0, sizeof(q->alloc_ctx));
 		q->memory = memory;
 		q->waiting_for_buffers = !q->is_output;
@@ -720,18 +850,23 @@ int vb2_core_create_bufs(struct vb2_queue *q, enum vb2_memory memory,
 
 	num_buffers = min(*count, VB2_MAX_FRAME - q->num_buffers);
 
+	if (requested_planes && requested_sizes) {
+		num_planes = requested_planes;
+		memcpy(plane_sizes, requested_sizes, sizeof(plane_sizes));
+	}
+
 	/*
 	 * Ask the driver, whether the requested number of buffers, planes per
 	 * buffer and their sizes are acceptable
 	 */
-	ret = call_qop(q, queue_setup, q, parg, &num_buffers,
-		       &num_planes, q->plane_sizes, q->alloc_ctx);
+	ret = call_qop(q, queue_setup, q, &num_buffers,
+		       &num_planes, plane_sizes, q->alloc_ctx);
 	if (ret)
 		return ret;
 
 	/* Finally, allocate buffers and video memory */
 	allocated_buffers = __vb2_queue_alloc(q, memory, num_buffers,
-				num_planes);
+				num_planes, plane_sizes);
 	if (allocated_buffers == 0) {
 		dprintk(1, "memory allocation failed\n");
 		return -ENOMEM;
@@ -747,8 +882,8 @@ int vb2_core_create_bufs(struct vb2_queue *q, enum vb2_memory memory,
 		 * q->num_buffers contains the total number of buffers, that the
 		 * queue driver has set up
 		 */
-		ret = call_qop(q, queue_setup, q, parg, &num_buffers,
-			       &num_planes, q->plane_sizes, q->alloc_ctx);
+		ret = call_qop(q, queue_setup, q, &num_buffers,
+			       &num_planes, plane_sizes, q->alloc_ctx);
 
 		if (!ret && allocated_buffers < num_buffers)
 			ret = -ENOMEM;
@@ -964,11 +1099,12 @@ static int __qbuf_userptr(struct vb2_buffer *vb, const void *pb)
 				"reacquiring memory\n", plane);
 
 		/* Check if the provided plane buffer is large enough */
-		if (planes[plane].length < q->plane_sizes[plane]) {
+		if (planes[plane].length < vb->planes[plane].min_length) {
 			dprintk(1, "provided buffer size %u is less than "
 						"setup size %u for plane %d\n",
 						planes[plane].length,
-						q->plane_sizes[plane], plane);
+						vb->planes[plane].min_length,
+						plane);
 			ret = -EINVAL;
 			goto err;
 		}
@@ -1081,7 +1217,7 @@ static int __qbuf_dmabuf(struct vb2_buffer *vb, const void *pb)
 		if (planes[plane].length == 0)
 			planes[plane].length = dbuf->size;
 
-		if (planes[plane].length < q->plane_sizes[plane]) {
+		if (planes[plane].length < vb->planes[plane].min_length) {
 			dprintk(1, "invalid dmabuf length for plane %d\n",
 				plane);
 			ret = -EINVAL;
@@ -1263,9 +1399,7 @@ int vb2_core_prepare_buf(struct vb2_queue *q, unsigned int index, void *pb)
 		return ret;
 
 	/* Fill buffer information for the userspace */
-	ret = call_bufop(q, fill_user_buffer, vb, pb);
-	if (ret)
-		return ret;
+	call_void_bufop(q, fill_user_buffer, vb, pb);
 
 	dprintk(1, "prepare of buffer %d succeeded\n", vb->index);
 
@@ -1386,7 +1520,7 @@ int vb2_core_qbuf(struct vb2_queue *q, unsigned int index, void *pb)
 	q->waiting_for_buffers = false;
 	vb->state = VB2_BUF_STATE_QUEUED;
 
-	call_bufop(q, set_timestamp, vb, pb);
+	call_void_bufop(q, copy_timestamp, vb, pb);
 
 	trace_vb2_qbuf(q, vb);
 
@@ -1398,9 +1532,7 @@ int vb2_core_qbuf(struct vb2_queue *q, unsigned int index, void *pb)
 		__enqueue_in_driver(vb);
 
 	/* Fill buffer information for the userspace */
-	ret = call_bufop(q, fill_user_buffer, vb, pb);
-	if (ret)
-		return ret;
+	call_void_bufop(q, fill_user_buffer, vb, pb);
 
 	/*
 	 * If streamon has been called, and we haven't yet called
@@ -1623,9 +1755,7 @@ int vb2_core_dqbuf(struct vb2_queue *q, void *pb, bool nonblocking)
 	call_void_vb_qop(vb, buf_finish, vb);
 
 	/* Fill buffer information for the userspace */
-	ret = call_bufop(q, fill_user_buffer, vb, pb);
-	if (ret)
-		return ret;
+	call_void_bufop(q, fill_user_buffer, vb, pb);
 
 	/* Remove from videobuf queue */
 	list_del(&vb->queued_entry);
@@ -2073,6 +2203,8 @@ int vb2_core_queue_init(struct vb2_queue *q)
 }
 EXPORT_SYMBOL_GPL(vb2_core_queue_init);
 
+static int __vb2_init_fileio(struct vb2_queue *q, int read);
+static int __vb2_cleanup_fileio(struct vb2_queue *q);
 /**
  * vb2_core_queue_release() - stop streaming, release the queue and free memory
  * @q:		videobuf2 queue
@@ -2083,6 +2215,7 @@ EXPORT_SYMBOL_GPL(vb2_core_queue_init);
  */
 void vb2_core_queue_release(struct vb2_queue *q)
 {
+	__vb2_cleanup_fileio(q);
 	__vb2_queue_cancel(q);
 	mutex_lock(&q->mmap_lock);
 	__vb2_queue_free(q, q->num_buffers);
@@ -2090,6 +2223,619 @@ void vb2_core_queue_release(struct vb2_queue *q)
 }
 EXPORT_SYMBOL_GPL(vb2_core_queue_release);
 
-MODULE_DESCRIPTION("Driver helper framework for Video for Linux 2");
+/**
+ * vb2_core_poll() - implements poll userspace operation
+ * @q:		videobuf2 queue
+ * @file:	file argument passed to the poll file operation handler
+ * @wait:	wait argument passed to the poll file operation handler
+ *
+ * This function implements poll file operation handler for a driver.
+ * For CAPTURE queues, if a buffer is ready to be dequeued, the userspace will
+ * be informed that the file descriptor of a video device is available for
+ * reading.
+ * For OUTPUT queues, if a buffer is ready to be dequeued, the file descriptor
+ * will be reported as available for writing.
+ *
+ * The return values from this function are intended to be directly returned
+ * from poll handler in driver.
+ */
+unsigned int vb2_core_poll(struct vb2_queue *q, struct file *file,
+		poll_table *wait)
+{
+	unsigned long req_events = poll_requested_events(wait);
+	struct vb2_buffer *vb = NULL;
+	unsigned long flags;
+
+	if (!q->is_output && !(req_events & (POLLIN | POLLRDNORM)))
+		return 0;
+	if (q->is_output && !(req_events & (POLLOUT | POLLWRNORM)))
+		return 0;
+
+	/*
+	 * Start file I/O emulator only if streaming API has not been used yet.
+	 */
+	if (q->num_buffers == 0 && !vb2_fileio_is_active(q)) {
+		if (!q->is_output && (q->io_modes & VB2_READ) &&
+				(req_events & (POLLIN | POLLRDNORM))) {
+			if (__vb2_init_fileio(q, 1))
+				return POLLERR;
+		}
+		if (q->is_output && (q->io_modes & VB2_WRITE) &&
+				(req_events & (POLLOUT | POLLWRNORM))) {
+			if (__vb2_init_fileio(q, 0))
+				return POLLERR;
+			/*
+			 * Write to OUTPUT queue can be done immediately.
+			 */
+			return POLLOUT | POLLWRNORM;
+		}
+	}
+
+	/*
+	 * There is nothing to wait for if the queue isn't streaming, or if the
+	 * error flag is set.
+	 */
+	if (!vb2_is_streaming(q) || q->error)
+		return POLLERR;
+
+	/*
+	 * For output streams you can call write() as long as there are fewer
+	 * buffers queued than there are buffers available.
+	 */
+	if (q->is_output && q->fileio && q->queued_count < q->num_buffers)
+		return POLLOUT | POLLWRNORM;
+
+	if (list_empty(&q->done_list)) {
+		/*
+		 * If the last buffer was dequeued from a capture queue,
+		 * return immediately. DQBUF will return -EPIPE.
+		 */
+		if (q->last_buffer_dequeued)
+			return POLLIN | POLLRDNORM;
+
+		poll_wait(file, &q->done_wq, wait);
+	}
+
+	/*
+	 * Take first buffer available for dequeuing.
+	 */
+	spin_lock_irqsave(&q->done_lock, flags);
+	if (!list_empty(&q->done_list))
+		vb = list_first_entry(&q->done_list, struct vb2_buffer,
+					done_entry);
+	spin_unlock_irqrestore(&q->done_lock, flags);
+
+	if (vb && (vb->state == VB2_BUF_STATE_DONE
+			|| vb->state == VB2_BUF_STATE_ERROR)) {
+		return (q->is_output) ?
+				POLLOUT | POLLWRNORM :
+				POLLIN | POLLRDNORM;
+	}
+	return 0;
+}
+EXPORT_SYMBOL_GPL(vb2_core_poll);
+
+/**
+ * struct vb2_fileio_buf - buffer context used by file io emulator
+ *
+ * vb2 provides a compatibility layer and emulator of file io (read and
+ * write) calls on top of streaming API. This structure is used for
+ * tracking context related to the buffers.
+ */
+struct vb2_fileio_buf {
+	void *vaddr;
+	unsigned int size;
+	unsigned int pos;
+	unsigned int queued:1;
+};
+
+/**
+ * struct vb2_fileio_data - queue context used by file io emulator
+ *
+ * @cur_index:	the index of the buffer currently being read from or
+ *		written to. If equal to q->num_buffers then a new buffer
+ *		must be dequeued.
+ * @initial_index: in the read() case all buffers are queued up immediately
+ *		in __vb2_init_fileio() and __vb2_perform_fileio() just cycles
+ *		buffers. However, in the write() case no buffers are initially
+ *		queued, instead whenever a buffer is full it is queued up by
+ *		__vb2_perform_fileio(). Only once all available buffers have
+ *		been queued up will __vb2_perform_fileio() start to dequeue
+ *		buffers. This means that initially __vb2_perform_fileio()
+ *		needs to know what buffer index to use when it is queuing up
+ *		the buffers for the first time. That initial index is stored
+ *		in this field. Once it is equal to q->num_buffers all
+ *		available buffers have been queued and __vb2_perform_fileio()
+ *		should start the normal dequeue/queue cycle.
+ *
+ * vb2 provides a compatibility layer and emulator of file io (read and
+ * write) calls on top of streaming API. For proper operation it required
+ * this structure to save the driver state between each call of the read
+ * or write function.
+ */
+struct vb2_fileio_data {
+	unsigned int count;
+	unsigned int type;
+	unsigned int memory;
+	struct vb2_buffer *b;
+	struct vb2_fileio_buf bufs[VB2_MAX_FRAME];
+	unsigned int cur_index;
+	unsigned int initial_index;
+	unsigned int q_count;
+	unsigned int dq_count;
+	unsigned read_once:1;
+	unsigned write_immediately:1;
+};
+
+/**
+ * __vb2_init_fileio() - initialize file io emulator
+ * @q:		videobuf2 queue
+ * @read:	mode selector (1 means read, 0 means write)
+ */
+static int __vb2_init_fileio(struct vb2_queue *q, int read)
+{
+	struct vb2_fileio_data *fileio;
+	int i, ret;
+	unsigned int count = 0;
+
+	/*
+	 * Sanity check
+	 */
+	if (WARN_ON((read && !(q->io_modes & VB2_READ)) ||
+		    (!read && !(q->io_modes & VB2_WRITE))))
+		return -EINVAL;
+
+	/*
+	 * Check if device supports mapping buffers to kernel virtual space.
+	 */
+	if (!q->mem_ops->vaddr)
+		return -EBUSY;
+
+	/*
+	 * Check if streaming api has not been already activated.
+	 */
+	if (q->streaming || q->num_buffers > 0)
+		return -EBUSY;
+
+	/*
+	 * Start with count 1, driver can increase it in queue_setup()
+	 */
+	count = 1;
+
+	dprintk(3, "setting up file io: mode %s, count %d, read_once %d, write_immediately %d\n",
+		(read) ? "read" : "write", count, q->fileio_read_once,
+		q->fileio_write_immediately);
+
+	fileio = kzalloc(sizeof(*fileio), GFP_KERNEL);
+	if (fileio == NULL)
+		return -ENOMEM;
+
+	fileio->b = kzalloc(q->buf_struct_size, GFP_KERNEL);
+	if (fileio->b == NULL) {
+		kfree(fileio);
+		return -ENOMEM;
+	}
+
+	fileio->read_once = q->fileio_read_once;
+	fileio->write_immediately = q->fileio_write_immediately;
+
+	/*
+	 * Request buffers and use MMAP type to force driver
+	 * to allocate buffers by itself.
+	 */
+	fileio->count = count;
+	fileio->memory = VB2_MEMORY_MMAP;
+	fileio->type = q->type;
+	q->fileio = fileio;
+	ret = vb2_core_reqbufs(q, fileio->memory, &fileio->count);
+	if (ret)
+		goto err_kfree;
+
+	/*
+	 * Check if plane_count is correct
+	 * (multiplane buffers are not supported).
+	 */
+	if (q->bufs[0]->num_planes != 1) {
+		ret = -EBUSY;
+		goto err_reqbufs;
+	}
+
+	/*
+	 * Get kernel address of each buffer.
+	 */
+	for (i = 0; i < q->num_buffers; i++) {
+		fileio->bufs[i].vaddr = vb2_plane_vaddr(q->bufs[i], 0);
+		if (fileio->bufs[i].vaddr == NULL) {
+			ret = -EINVAL;
+			goto err_reqbufs;
+		}
+		fileio->bufs[i].size = vb2_plane_size(q->bufs[i], 0);
+	}
+
+	/*
+	 * Read mode requires pre queuing of all buffers.
+	 */
+	if (read) {
+		/*
+		 * Queue all buffers.
+		 */
+		for (i = 0; i < q->num_buffers; i++) {
+			struct vb2_buffer *b = fileio->b;
+
+			memset(b, 0, q->buf_struct_size);
+			b->type = q->type;
+			b->memory = q->memory;
+			b->index = i;
+			ret = vb2_core_qbuf(q, i, b);
+			if (ret)
+				goto err_reqbufs;
+			fileio->bufs[i].queued = 1;
+		}
+		/*
+		 * All buffers have been queued, so mark that by setting
+		 * initial_index to q->num_buffers
+		 */
+		fileio->initial_index = q->num_buffers;
+		fileio->cur_index = q->num_buffers;
+	}
+
+	/*
+	 * Start streaming.
+	 */
+	ret = vb2_core_streamon(q, q->type);
+	if (ret)
+		goto err_reqbufs;
+
+	return ret;
+
+err_reqbufs:
+	fileio->count = 0;
+	vb2_core_reqbufs(q, fileio->memory, &fileio->count);
+
+err_kfree:
+	q->fileio = NULL;
+	kfree(fileio);
+	return ret;
+}
+
+/**
+ * __vb2_cleanup_fileio() - free resourced used by file io emulator
+ * @q:		videobuf2 queue
+ */
+static int __vb2_cleanup_fileio(struct vb2_queue *q)
+{
+	struct vb2_fileio_data *fileio = q->fileio;
+
+	if (fileio) {
+		vb2_core_streamoff(q, q->type);
+		q->fileio = NULL;
+		fileio->count = 0;
+		vb2_core_reqbufs(q, fileio->memory, &fileio->count);
+		kfree(fileio->b);
+		kfree(fileio);
+		dprintk(3, "file io emulator closed\n");
+	}
+	return 0;
+}
+
+/**
+ * __vb2_perform_fileio() - perform a single file io (read or write) operation
+ * @q:		videobuf2 queue
+ * @data:	pointed to target userspace buffer
+ * @count:	number of bytes to read or write
+ * @ppos:	file handle position tracking pointer
+ * @nonblock:	mode selector (1 means blocking calls, 0 means nonblocking)
+ * @read:	access mode selector (1 means read, 0 means write)
+ */
+static size_t __vb2_perform_fileio(struct vb2_queue *q, char __user *data, size_t count,
+		loff_t *ppos, int nonblock, int read)
+{
+	struct vb2_fileio_data *fileio;
+	struct vb2_fileio_buf *buf;
+	bool is_multiplanar = q->is_multiplanar;
+	/*
+	 * When using write() to write data to an output video node the vb2 core
+	 * should copy timestamps if V4L2_BUF_FLAG_TIMESTAMP_COPY is set. Nobody
+	 * else is able to provide this information with the write() operation.
+	 */
+	bool copy_timestamp = !read && q->copy_timestamp;
+	int ret, index;
+
+	dprintk(3, "mode %s, offset %ld, count %zd, %sblocking\n",
+		read ? "read" : "write", (long)*ppos, count,
+		nonblock ? "non" : "");
+
+	if (!data)
+		return -EINVAL;
+
+	/*
+	 * Initialize emulator on first call.
+	 */
+	if (!vb2_fileio_is_active(q)) {
+		ret = __vb2_init_fileio(q, read);
+		dprintk(3, "vb2_init_fileio result: %d\n", ret);
+		if (ret)
+			return ret;
+	}
+	fileio = q->fileio;
+
+	/*
+	 * Check if we need to dequeue the buffer.
+	 */
+	index = fileio->cur_index;
+	if (index >= q->num_buffers) {
+		struct vb2_buffer *b = fileio->b;
+
+		/*
+		 * Call vb2_dqbuf to get buffer back.
+		 */
+		memset(b, 0, q->buf_struct_size);
+		b->type = q->type;
+		b->memory = q->memory;
+		ret = vb2_core_dqbuf(q, b, nonblock);
+		dprintk(5, "vb2_dqbuf result: %d\n", ret);
+		if (ret)
+			return ret;
+		fileio->dq_count += 1;
+
+		fileio->cur_index = index = b->index;
+		buf = &fileio->bufs[index];
+
+		/*
+		 * Get number of bytes filled by the driver
+		 */
+		buf->pos = 0;
+		buf->queued = 0;
+		buf->size = read ? vb2_get_plane_payload(q->bufs[index], 0)
+				 : vb2_plane_size(q->bufs[index], 0);
+		/* Compensate for data_offset on read in the multiplanar case. */
+		if (is_multiplanar && read &&
+				b->planes[0].data_offset < buf->size) {
+			buf->pos = b->planes[0].data_offset;
+			buf->size -= buf->pos;
+		}
+	} else {
+		buf = &fileio->bufs[index];
+	}
+
+	/*
+	 * Limit count on last few bytes of the buffer.
+	 */
+	if (buf->pos + count > buf->size) {
+		count = buf->size - buf->pos;
+		dprintk(5, "reducing read count: %zd\n", count);
+	}
+
+	/*
+	 * Transfer data to userspace.
+	 */
+	dprintk(3, "copying %zd bytes - buffer %d, offset %u\n",
+		count, index, buf->pos);
+	if (read)
+		ret = copy_to_user(data, buf->vaddr + buf->pos, count);
+	else
+		ret = copy_from_user(buf->vaddr + buf->pos, data, count);
+	if (ret) {
+		dprintk(3, "error copying data\n");
+		return -EFAULT;
+	}
+
+	/*
+	 * Update counters.
+	 */
+	buf->pos += count;
+	*ppos += count;
+
+	/*
+	 * Queue next buffer if required.
+	 */
+	if (buf->pos == buf->size || (!read && fileio->write_immediately)) {
+		struct vb2_buffer *b = fileio->b;
+
+		/*
+		 * Check if this is the last buffer to read.
+		 */
+		if (read && fileio->read_once && fileio->dq_count == 1) {
+			dprintk(3, "read limit reached\n");
+			return __vb2_cleanup_fileio(q);
+		}
+
+		/*
+		 * Call vb2_qbuf and give buffer to the driver.
+		 */
+		memset(b, 0, q->buf_struct_size);
+		b->type = q->type;
+		b->memory = q->memory;
+		b->index = index;
+		b->planes[0].bytesused = buf->pos;
+
+		if (copy_timestamp)
+			b->timestamp = ktime_get_ns();
+		ret = vb2_core_qbuf(q, index, b);
+		dprintk(5, "vb2_dbuf result: %d\n", ret);
+		if (ret)
+			return ret;
+
+		/*
+		 * Buffer has been queued, update the status
+		 */
+		buf->pos = 0;
+		buf->queued = 1;
+		buf->size = vb2_plane_size(q->bufs[index], 0);
+		fileio->q_count += 1;
+		/*
+		 * If we are queuing up buffers for the first time, then
+		 * increase initial_index by one.
+		 */
+		if (fileio->initial_index < q->num_buffers)
+			fileio->initial_index++;
+		/*
+		 * The next buffer to use is either a buffer that's going to be
+		 * queued for the first time (initial_index < q->num_buffers)
+		 * or it is equal to q->num_buffers, meaning that the next
+		 * time we need to dequeue a buffer since we've now queued up
+		 * all the 'first time' buffers.
+		 */
+		fileio->cur_index = fileio->initial_index;
+	}
+
+	/*
+	 * Return proper number of bytes processed.
+	 */
+	if (ret == 0)
+		ret = count;
+	return ret;
+}
+
+size_t vb2_read(struct vb2_queue *q, char __user *data, size_t count,
+		loff_t *ppos, int nonblocking)
+{
+	return __vb2_perform_fileio(q, data, count, ppos, nonblocking, 1);
+}
+EXPORT_SYMBOL_GPL(vb2_read);
+
+size_t vb2_write(struct vb2_queue *q, const char __user *data, size_t count,
+		loff_t *ppos, int nonblocking)
+{
+	return __vb2_perform_fileio(q, (char __user *) data, count,
+							ppos, nonblocking, 0);
+}
+EXPORT_SYMBOL_GPL(vb2_write);
+
+struct vb2_threadio_data {
+	struct task_struct *thread;
+	vb2_thread_fnc fnc;
+	void *priv;
+	bool stop;
+};
+
+static int vb2_thread(void *data)
+{
+	struct vb2_queue *q = data;
+	struct vb2_threadio_data *threadio = q->threadio;
+	struct vb2_fileio_data *fileio = q->fileio;
+	bool copy_timestamp = false;
+	int prequeue = 0;
+	int index = 0;
+	int ret = 0;
+
+	if (q->is_output) {
+		prequeue = q->num_buffers;
+		copy_timestamp = q->copy_timestamp;
+	}
+
+	set_freezable();
+
+	for (;;) {
+		struct vb2_buffer *vb;
+		struct vb2_buffer *b = fileio->b;
+
+		/*
+		 * Call vb2_dqbuf to get buffer back.
+		 */
+		memset(b, 0, q->buf_struct_size);
+		b->type = q->type;
+		b->memory = q->memory;
+		if (prequeue) {
+			b->index = index++;
+			prequeue--;
+		} else {
+			call_void_qop(q, wait_finish, q);
+			if (!threadio->stop)
+				ret = vb2_core_dqbuf(q, b, 0);
+			call_void_qop(q, wait_prepare, q);
+			dprintk(5, "file io: vb2_dqbuf result: %d\n", ret);
+		}
+		if (ret || threadio->stop)
+			break;
+		try_to_freeze();
+
+		vb = q->bufs[b->index];
+		if (b->state == VB2_BUF_STATE_DONE)
+			if (threadio->fnc(vb, threadio->priv))
+				break;
+		call_void_qop(q, wait_finish, q);
+		if (copy_timestamp)
+			b->timestamp = ktime_get_ns();;
+		if (!threadio->stop)
+			ret = vb2_core_qbuf(q, b->index, b);
+		call_void_qop(q, wait_prepare, q);
+		if (ret || threadio->stop)
+			break;
+	}
+
+	/* Hmm, linux becomes *very* unhappy without this ... */
+	while (!kthread_should_stop()) {
+		set_current_state(TASK_INTERRUPTIBLE);
+		schedule();
+	}
+	return 0;
+}
+
+/*
+ * This function should not be used for anything else but the videobuf2-dvb
+ * support. If you think you have another good use-case for this, then please
+ * contact the linux-media mailinglist first.
+ */
+int vb2_thread_start(struct vb2_queue *q, vb2_thread_fnc fnc, void *priv,
+		     const char *thread_name)
+{
+	struct vb2_threadio_data *threadio;
+	int ret = 0;
+
+	if (q->threadio)
+		return -EBUSY;
+	if (vb2_is_busy(q))
+		return -EBUSY;
+	if (WARN_ON(q->fileio))
+		return -EBUSY;
+
+	threadio = kzalloc(sizeof(*threadio), GFP_KERNEL);
+	if (threadio == NULL)
+		return -ENOMEM;
+	threadio->fnc = fnc;
+	threadio->priv = priv;
+
+	ret = __vb2_init_fileio(q, !q->is_output);
+	dprintk(3, "file io: vb2_init_fileio result: %d\n", ret);
+	if (ret)
+		goto nomem;
+	q->threadio = threadio;
+	threadio->thread = kthread_run(vb2_thread, q, "vb2-%s", thread_name);
+	if (IS_ERR(threadio->thread)) {
+		ret = PTR_ERR(threadio->thread);
+		threadio->thread = NULL;
+		goto nothread;
+	}
+	return 0;
+
+nothread:
+	__vb2_cleanup_fileio(q);
+nomem:
+	kfree(threadio);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(vb2_thread_start);
+
+int vb2_thread_stop(struct vb2_queue *q)
+{
+	struct vb2_threadio_data *threadio = q->threadio;
+	int err;
+
+	if (threadio == NULL)
+		return 0;
+	threadio->stop = true;
+	/* Wake up all pending sleeps in the thread */
+	vb2_queue_error(q);
+	err = kthread_stop(threadio->thread);
+	__vb2_cleanup_fileio(q);
+	threadio->thread = NULL;
+	kfree(threadio);
+	q->threadio = NULL;
+	return err;
+}
+EXPORT_SYMBOL_GPL(vb2_thread_stop);
+
+MODULE_DESCRIPTION("Media buffer core framework");
 MODULE_AUTHOR("Pawel Osciak <pawel@osciak.com>, Marek Szyprowski");
 MODULE_LICENSE("GPL");