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[1/8] v4l: add videobuf2 Video for Linux 2 driver framework

Message ID 1291632765-11207-2-git-send-email-m.szyprowski@samsung.com (mailing list archive)
State RFC
Headers show

Commit Message

Marek Szyprowski Dec. 6, 2010, 10:52 a.m. UTC
None
diff mbox

Patch

diff --git a/drivers/media/video/Kconfig b/drivers/media/video/Kconfig
index ac16e81..fef6a14 100644
--- a/drivers/media/video/Kconfig
+++ b/drivers/media/video/Kconfig
@@ -49,6 +49,9 @@  config V4L2_MEM2MEM_DEV
 	tristate
 	depends on VIDEOBUF_GEN
 
+config VIDEOBUF2_CORE
+	tristate
+
 #
 # Multimedia Video device configuration
 #
diff --git a/drivers/media/video/Makefile b/drivers/media/video/Makefile
index af79d47..77c4f85 100644
--- a/drivers/media/video/Makefile
+++ b/drivers/media/video/Makefile
@@ -114,6 +114,8 @@  obj-$(CONFIG_VIDEOBUF_VMALLOC) += videobuf-vmalloc.o
 obj-$(CONFIG_VIDEOBUF_DVB) += videobuf-dvb.o
 obj-$(CONFIG_VIDEO_BTCX)  += btcx-risc.o
 
+obj-$(CONFIG_VIDEOBUF2_CORE)		+= videobuf2-core.o
+
 obj-$(CONFIG_V4L2_MEM2MEM_DEV) += v4l2-mem2mem.o
 
 obj-$(CONFIG_VIDEO_M32R_AR_M64278) += arv.o
diff --git a/drivers/media/video/videobuf2-core.c b/drivers/media/video/videobuf2-core.c
new file mode 100644
index 0000000..e149acd
--- /dev/null
+++ b/drivers/media/video/videobuf2-core.c
@@ -0,0 +1,1400 @@ 
+/*
+ * videobuf2-core.c - V4L2 driver helper framework
+ *
+ * Copyright (C) 2010 Samsung Electronics
+ *
+ * Author: Pawel Osciak <p.osciak@samsung.com>
+ *	   Marek Szyprowski <m.szyprowski@samsung.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation.
+ */
+
+#include <linux/err.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/mm.h>
+#include <linux/poll.h>
+#include <linux/slab.h>
+#include <linux/sched.h>
+
+#include <media/videobuf2-core.h>
+
+static int debug;
+module_param(debug, int, 0644);
+
+#define dprintk(level, fmt, arg...)					\
+	do {								\
+		if (debug >= level)					\
+			printk(KERN_DEBUG "vb2: " fmt, ## arg);		\
+	} while (0)
+
+#define call_memop(q, plane, op, args...)				\
+	(((q)->mem_ops->op) ?						\
+		((q)->mem_ops->op(args)) : 0)
+
+#define call_qop(q, op, args...)					\
+	(((q)->ops->op) ? ((q)->ops->op(args)) : 0)
+
+/**
+ * __vb2_buf_mem_alloc() - allocate video memory for the given buffer
+ */
+static int __vb2_buf_mem_alloc(struct vb2_buffer *vb,
+				unsigned long *plane_sizes)
+{
+	struct vb2_queue *q = vb->vb2_queue;
+	void *mem_priv;
+	int plane;
+
+	/* Allocate memory for all planes in this buffer */
+	for (plane = 0; plane < vb->num_planes; ++plane) {
+		mem_priv = call_memop(q, plane, alloc, q->alloc_ctx[plane],
+					plane_sizes[plane]);
+		if (!mem_priv)
+			goto free;
+
+		/* Associate allocator private data with this plane */
+		vb->planes[plane].mem_priv = mem_priv;
+		vb->v4l2_planes[plane].length = plane_sizes[plane];
+	}
+
+	return 0;
+free:
+	/* Free already allocated memory if one of the allocations failed */
+	for (; plane > 0; --plane)
+		call_memop(q, plane, put, vb->planes[plane - 1].mem_priv);
+
+	return -ENOMEM;
+}
+
+/**
+ * __vb2_buf_mem_free() - free memory of the given buffer
+ */
+static void __vb2_buf_mem_free(struct vb2_buffer *vb)
+{
+	struct vb2_queue *q = vb->vb2_queue;
+	unsigned int plane;
+
+	for (plane = 0; plane < vb->num_planes; ++plane) {
+		call_memop(q, plane, put, vb->planes[plane].mem_priv);
+		vb->planes[plane].mem_priv = NULL;
+		dprintk(3, "Freed plane %d of buffer %d\n",
+				plane, vb->v4l2_buf.index);
+	}
+}
+
+/**
+ * __vb2_buf_userptr_put() - release userspace memory associated associated
+ * with a USERPTR buffer
+ */
+static void __vb2_buf_userptr_put(struct vb2_buffer *vb)
+{
+	struct vb2_queue *q = vb->vb2_queue;
+	unsigned int plane;
+
+	for (plane = 0; plane < vb->num_planes; ++plane) {
+		void *mem_priv = vb->planes[plane].mem_priv;
+		if (mem_priv) {
+			call_memop(q, plane, put_userptr, mem_priv);
+			vb->planes[plane].mem_priv = NULL;
+		}
+	}
+}
+
+/**
+ * __setup_offsets() - setup unique offsets ("cookies") for every plane in
+ * every buffer on the queue
+ */
+static void __setup_offsets(struct vb2_queue *q)
+{
+	unsigned int buffer, plane;
+	struct vb2_buffer *vb;
+	unsigned long off = 0;
+
+	for (buffer = 0; buffer < q->num_buffers; ++buffer) {
+		vb = q->bufs[buffer];
+		if (!vb)
+			continue;
+
+		for (plane = 0; plane < vb->num_planes; ++plane) {
+			vb->v4l2_planes[plane].m.mem_offset = off;
+
+			dprintk(3, "Buffer %d, plane %d offset 0x%08lx\n",
+					buffer, plane, off);
+
+			off += vb->v4l2_planes[plane].length;
+			off = PAGE_ALIGN(off);
+		}
+	}
+}
+
+/**
+ * __vb2_queue_alloc() - allocate videobuf buffer structures and (for MMAP type)
+ * video buffer memory for all buffers/planes on the queue and initializes the
+ * queue
+ *
+ * Returns the number of buffers successfully allocated.
+ */
+static int __vb2_queue_alloc(struct vb2_queue *q, enum v4l2_memory memory,
+			     unsigned int num_buffers, unsigned int num_planes,
+			     unsigned long plane_sizes[])
+{
+	unsigned int buffer;
+	struct vb2_buffer *vb;
+	int ret;
+
+	for (buffer = 0; buffer < num_buffers; ++buffer) {
+		/* Allocate videobuf buffer structures */
+		vb = kzalloc(q->buf_struct_size, GFP_KERNEL);
+		if (!vb) {
+			dprintk(1, "Memory alloc for buffer struct failed\n");
+			break;
+		}
+
+		/* Length stores number of planes for multiplanar buffers */
+		if (V4L2_TYPE_IS_MULTIPLANAR(q->type))
+			vb->v4l2_buf.length = num_planes;
+
+		vb->state = VB2_BUF_STATE_DEQUEUED;
+		vb->vb2_queue = q;
+		vb->num_planes = num_planes;
+		vb->v4l2_buf.index = buffer;
+		vb->v4l2_buf.type = q->type;
+		vb->v4l2_buf.memory = memory;
+
+		/* Allocate video buffer memory for the MMAP type */
+		if (memory == V4L2_MEMORY_MMAP) {
+			ret = __vb2_buf_mem_alloc(vb, plane_sizes);
+			if (ret) {
+				dprintk(1, "Failed allocating memory for "
+						"buffer %d\n", buffer);
+				kfree(vb);
+				break;
+			}
+			/*
+			 * Call the driver-provided buffer initialization
+			 * callback, if given. An error in initialization
+			 * results in queue setup failure.
+			 */
+			ret = call_qop(q, buf_init, vb);
+			if (ret) {
+				dprintk(1, "Buffer %d %p initialization"
+					" failed\n", buffer, vb);
+				__vb2_buf_mem_free(vb);
+				kfree(vb);
+				break;
+			}
+		}
+
+		q->bufs[buffer] = vb;
+	}
+
+	q->num_buffers = buffer;
+
+	__setup_offsets(q);
+
+	dprintk(1, "Allocated %d buffers, %d plane(s) each\n",
+			q->num_buffers, num_planes);
+
+	return buffer;
+}
+
+/**
+ * __vb2_free_mem() - release all video buffer memory for a given queue
+ */
+static void __vb2_free_mem(struct vb2_queue *q)
+{
+	unsigned int buffer;
+	struct vb2_buffer *vb;
+
+	for (buffer = 0; buffer < q->num_buffers; ++buffer) {
+		vb = q->bufs[buffer];
+		if (!vb)
+			continue;
+
+		/* Free MMAP buffers or release USERPTR buffers */
+		if (q->memory == V4L2_MEMORY_MMAP)
+			__vb2_buf_mem_free(vb);
+		else
+			__vb2_buf_userptr_put(vb);
+	}
+}
+
+/**
+ * __vb2_queue_free() - free the queue - video memory and related information
+ * and return the queue to an uninitialized state
+ */
+static int __vb2_queue_free(struct vb2_queue *q)
+{
+	unsigned int buffer;
+
+	/* Call driver-provided cleanup function for each buffer, if provided */
+	if (q->ops->buf_cleanup) {
+		for (buffer = 0; buffer < q->num_buffers; ++buffer) {
+			if (NULL == q->bufs[buffer])
+				continue;
+			q->ops->buf_cleanup(q->bufs[buffer]);
+		}
+	}
+
+	/* Release video buffer memory */
+	__vb2_free_mem(q);
+
+	/* Free videobuf buffers */
+	for (buffer = 0; buffer < q->num_buffers; ++buffer) {
+		if (NULL == q->bufs[buffer])
+			continue;
+		kfree(q->bufs[buffer]);
+		q->bufs[buffer] = NULL;
+	}
+
+	q->num_buffers = 0;
+	q->memory = 0;
+
+	return 0;
+}
+
+/**
+ * __verify_planes_array() - verify that the planes array passed in struct
+ * v4l2_buffer from userspace can be safely used
+ */
+static int __verify_planes_array(struct vb2_buffer *vb, struct v4l2_buffer *b)
+{
+	/* Is memory for copying plane information present? */
+	if (NULL == b->m.planes) {
+		dprintk(1, "Multi-planar buffer passed but "
+			   "planes array not provided\n");
+		return -EINVAL;
+	}
+
+	if (b->length < vb->num_planes || b->length > VIDEO_MAX_PLANES) {
+		dprintk(1, "Incorrect planes array length, "
+			   "expected %d, got %d\n", vb->num_planes, b->length);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+/**
+ * __fill_v4l2_buffer() - fill in a struct v4l2_buffer with information to be
+ * returned to userspace
+ */
+static int __fill_v4l2_buffer(struct vb2_buffer *vb, struct v4l2_buffer *b)
+{
+	struct vb2_queue *q = vb->vb2_queue;
+	int ret = 0;
+
+	/* Copy back data such as timestamp, input, etc. */
+	memcpy(b, &vb->v4l2_buf, offsetof(struct v4l2_buffer, m));
+	b->input = vb->v4l2_buf.input;
+	b->reserved = vb->v4l2_buf.reserved;
+
+	if (V4L2_TYPE_IS_MULTIPLANAR(q->type)) {
+		ret = __verify_planes_array(vb, b);
+		if (ret)
+			return ret;
+
+		/*
+		 * Fill in plane-related data if userspace provided an array
+		 * for it. The memory and size is verified above.
+		 */
+		memcpy(b->m.planes, vb->v4l2_planes,
+			b->length * sizeof(struct v4l2_plane));
+	} else {
+		/*
+		 * We use length and offset in v4l2_planes array even for
+		 * single-planar buffers, but userspace does not.
+		 */
+		b->length = vb->v4l2_planes[0].length;
+		b->bytesused = vb->v4l2_planes[0].bytesused;
+		if (q->memory == V4L2_MEMORY_MMAP)
+			b->m.offset = vb->v4l2_planes[0].m.mem_offset;
+		else if (q->memory == V4L2_MEMORY_USERPTR)
+			b->m.userptr = vb->v4l2_planes[0].m.userptr;
+	}
+
+	b->flags = 0;
+
+	switch (vb->state) {
+	case VB2_BUF_STATE_QUEUED:
+	case VB2_BUF_STATE_ACTIVE:
+		b->flags |= V4L2_BUF_FLAG_QUEUED;
+		break;
+	case VB2_BUF_STATE_ERROR:
+		b->flags |= V4L2_BUF_FLAG_ERROR;
+		/* fall through */
+	case VB2_BUF_STATE_DONE:
+		b->flags |= V4L2_BUF_FLAG_DONE;
+		break;
+	case VB2_BUF_STATE_DEQUEUED:
+		/* nothing */
+		break;
+	}
+
+	if (vb->num_planes_mapped == vb->num_planes)
+		b->flags |= V4L2_BUF_FLAG_MAPPED;
+
+	return ret;
+}
+
+/**
+ * vb2_querybuf() - query video buffer information
+ * @q:		videobuf queue
+ * @b:		buffer struct passed from userspace to vidioc_querybuf handler
+ *		in driver
+ *
+ * Should be called from vidioc_querybuf ioctl handler in driver.
+ * This function will verify the passed v4l2_buffer structure and fill 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_querybuf(struct vb2_queue *q, struct v4l2_buffer *b)
+{
+	struct vb2_buffer *vb;
+
+	if (b->type != q->type) {
+		dprintk(1, "querybuf: wrong buffer type\n");
+		return -EINVAL;
+	}
+
+	if (b->index >= q->num_buffers) {
+		dprintk(1, "querybuf: buffer index out of range\n");
+		return -EINVAL;
+	}
+	vb = q->bufs[b->index];
+
+	return __fill_v4l2_buffer(vb, b);
+}
+EXPORT_SYMBOL(vb2_querybuf);
+
+/**
+ * __verify_userptr_ops() - verify that all memory operations required for
+ * USERPTR queue type have been provided
+ */
+static int __verify_userptr_ops(struct vb2_queue *q)
+{
+	if (!(q->io_modes & VB2_USERPTR) || !q->mem_ops->get_userptr ||
+	    !q->mem_ops->put_userptr)
+		return -EINVAL;
+
+	return 0;
+}
+
+/**
+ * __verify_mmap_ops() - verify that all memory operations required for
+ * MMAP queue type have been provided
+ */
+static int __verify_mmap_ops(struct vb2_queue *q)
+{
+	if (!(q->io_modes & VB2_MMAP) || !q->mem_ops->alloc ||
+	    !q->mem_ops->put || !q->mem_ops->mmap)
+		return -EINVAL;
+
+	return 0;
+}
+
+/**
+ * __buffers_in_use() - return true if any buffers on the queue are in use and
+ * the queue cannot be freed (by the means of REQBUFS(0)) call
+ */
+static bool __buffers_in_use(struct vb2_queue *q)
+{
+	unsigned int buffer, plane;
+	struct vb2_buffer *vb;
+
+	for (buffer = 0; buffer < q->num_buffers; ++buffer) {
+		vb = q->bufs[buffer];
+		for (plane = 0; plane < vb->num_planes; ++plane) {
+			/*
+			 * If num_users() has not been provided, call_memop will
+			 * return 0, apparently nobody cares of this case anyway.
+			 * If num_users() returns more than 1, we are not the
+			 * only user of the plane's memory.
+			 */
+			if (call_memop(q, plane, num_users,
+					vb->planes[plane].mem_priv) > 1)
+				return true;
+		}
+	}
+
+	return false;
+}
+
+/**
+ * vb2_reqbufs() - Initiate streaming
+ * @q:		videobuf2 queue
+ * @req:	struct passed from userspace to vidioc_reqbufs handler in driver
+ *
+ * Should be called from vidioc_reqbufs ioctl handler of a driver.
+ * This function:
+ * 1) verifies streaming parameters passed from the userspace,
+ * 2) sets up the queue,
+ * 3) negotiates number of buffers and planes per buffer with the driver
+ *    to be used during streaming,
+ * 4) allocates internal buffer structures (struct vb2_buffer), according to
+ *    the agreed parameters,
+ * 5) for MMAP memory type, allocates actual video memory, using the
+ *    memory handling/allocation routines provided during queue initialization
+ *
+ * If req->count is 0, all the memory will be freed instead.
+ * If the queue has been allocated previously (by a previous vb2_reqbufs) call
+ * and the queue is not busy, memory will be reallocated.
+ *
+ * The return values from this function are intended to be directly returned
+ * from vidioc_reqbufs handler in driver.
+ */
+int vb2_reqbufs(struct vb2_queue *q, struct v4l2_requestbuffers *req)
+{
+	unsigned int num_buffers, num_planes;
+	unsigned long plane_sizes[VIDEO_MAX_PLANES];
+	int ret = 0;
+
+	if (req->memory != V4L2_MEMORY_MMAP
+			&& req->memory != V4L2_MEMORY_USERPTR) {
+		dprintk(1, "reqbufs: unsupported memory type\n");
+		return -EINVAL;
+	}
+
+	if (req->type != q->type) {
+		dprintk(1, "reqbufs: requested type is incorrect\n");
+		return -EINVAL;
+	}
+
+	if (q->streaming) {
+		dprintk(1, "reqbufs: streaming active\n");
+		return -EBUSY;
+	}
+
+	/*
+	 * Make sure all the required memory ops for given memory type
+	 * are available.
+	 */
+	if (req->memory == V4L2_MEMORY_MMAP && __verify_mmap_ops(q)) {
+		dprintk(1, "reqbufs: MMAP for current setup unsupported\n");
+		return -EINVAL;
+	} else if (req->memory == V4L2_MEMORY_USERPTR &&
+		   __verify_userptr_ops(q)) {
+		dprintk(1, "reqbufs: USERPTR for current setup unsupported\n");
+		return -EINVAL;
+	}
+
+	if (req->count == 0 || q->num_buffers != 0) {
+		/*
+		 * We already have buffers allocated, so first check if they
+		 * are not in use and can be freed.
+		 */
+		if (q->memory == V4L2_MEMORY_MMAP && __buffers_in_use(q)) {
+			dprintk(1, "reqbufs: memory in use, cannot free\n");
+			return -EBUSY;
+		}
+
+		ret = __vb2_queue_free(q);
+		if (ret != 0)
+			return ret;
+	}
+
+	/*
+	 * Make sure the requested values and current defaults are sane.
+	 */
+	num_buffers = min_t(unsigned int, req->count, VIDEO_MAX_FRAME);
+	memset(plane_sizes, 0, sizeof(plane_sizes));
+	memset(q->alloc_ctx, 0, sizeof(q->alloc_ctx));
+
+	/*
+	 * 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, &num_buffers, &num_planes,
+		       plane_sizes, q->alloc_ctx);
+	if (ret)
+		return ret;
+
+	/* Finally, allocate buffers and video memory */
+	ret = __vb2_queue_alloc(q, req->memory, num_buffers, num_planes,
+				plane_sizes);
+	if (ret < 0) {
+		dprintk(1, "Memory allocation failed with error: %d\n", ret);
+		return ret;
+	}
+
+	/*
+	 * Check if driver can handle the allocated number of buffers.
+	 */
+	if (ret < num_buffers) {
+		unsigned int num_buffers2;
+		num_buffers2 = ret;
+		ret = call_qop(q, queue_setup, q, &num_buffers, &num_planes,
+			       plane_sizes, q->alloc_ctx);
+		if (ret)
+			goto free_mem;
+
+		if (num_buffers2 < num_buffers) {
+			ret = -ENOMEM;
+			goto free_mem;
+		}
+
+		/*
+		 * Ok, driver accepted smaller number of buffers.
+		 */
+	}
+
+	q->memory = req->memory;
+
+	/*
+	 * Return the number of successfully allocated buffers
+	 * to the userspace.
+	 */
+	req->count = ret;
+
+	return 0;
+
+free_mem:
+	__vb2_queue_free(q);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(vb2_reqbufs);
+
+/**
+ * vb2_plane_vaddr() - Return a kernel virtual address of a given plane
+ * @vb:		vb2_buffer to which the plane in question belongs to
+ * @plane_no:	plane number for which the address is to be returned
+ *
+ * This function returns a kernel virtual address of a given plane if
+ * such a mapping exist, NULL otherwise.
+ */
+void *vb2_plane_vaddr(struct vb2_buffer *vb, unsigned int plane_no)
+{
+	struct vb2_queue *q = vb->vb2_queue;
+
+	if (plane_no > vb->num_planes)
+		return NULL;
+
+	return call_memop(q, plane_no, vaddr, vb->planes[plane_no].mem_priv);
+
+}
+EXPORT_SYMBOL_GPL(vb2_plane_vaddr);
+
+/**
+ * vb2_plane_cookie() - Return allocator specific cookie for the given plane
+ * @vb:		vb2_buffer to which the plane in question belongs to
+ * @plane_no:	plane number for which the address is to be returned
+ *
+ * This function returns an allocator specific cookie for a given plane if
+ * available, NULL otherwise. The allocator should provide some simple static
+ * inline function which converts this cookie to the allocator specific type
+ * that can be used directly by the driver to access the buffer. This can be
+ * for example physical address, pointer to scatter list or iommu mapping.
+ */
+void *vb2_plane_cookie(struct vb2_buffer *vb, unsigned int plane_no)
+{
+	struct vb2_queue *q = vb->vb2_queue;
+
+	if (plane_no > vb->num_planes)
+		return NULL;
+
+	return call_memop(q, plane_no, cookie, vb->planes[plane_no].mem_priv);
+}
+EXPORT_SYMBOL_GPL(vb2_plane_cookie);
+
+/**
+ * vb2_buffer_done() - inform videobuf that an operation on a buffer is finished
+ * @vb:		vb2_buffer returned from the driver
+ * @state:	either VB2_BUF_STATE_DONE if the operation finished successfully
+ *		or VB2_BUF_STATE_ERROR if the operation finished with an error
+ *
+ * This function should be called by the driver after a hardware operation on
+ * a buffer is finished and the buffer may be returned to userspace. The driver
+ * cannot use this buffer anymore until it is queued back to it by videobuf
+ * by the means of buf_queue callback. Only buffers previously queued to the
+ * driver by buf_queue can be passed to this function.
+ */
+void vb2_buffer_done(struct vb2_buffer *vb, enum vb2_buffer_state state)
+{
+	struct vb2_queue *q = vb->vb2_queue;
+	unsigned long flags;
+
+	if (vb->state != VB2_BUF_STATE_ACTIVE)
+		return;
+
+	if (state != VB2_BUF_STATE_DONE && state != VB2_BUF_STATE_ERROR)
+		return;
+
+	dprintk(4, "Done processing on buffer %d, state: %d\n",
+			vb->v4l2_buf.index, vb->state);
+
+	/* Add the buffer to the done buffers list */
+	spin_lock_irqsave(&q->done_lock, flags);
+	vb->state = state;
+	list_add_tail(&vb->done_entry, &q->done_list);
+	atomic_dec(&q->queued_count);
+	spin_unlock_irqrestore(&q->done_lock, flags);
+
+	/* Inform any processes that may be waiting for buffers */
+	wake_up(&q->done_wq);
+}
+EXPORT_SYMBOL_GPL(vb2_buffer_done);
+
+/**
+ * __fill_vb2_buffer() - fill a vb2_buffer with information provided in
+ * a v4l2_buffer by the userspace
+ */
+static int __fill_vb2_buffer(struct vb2_buffer *vb, struct v4l2_buffer *b,
+				struct v4l2_plane *v4l2_planes)
+{
+	unsigned int plane;
+	int ret;
+
+	if (V4L2_TYPE_IS_MULTIPLANAR(b->type)) {
+		/*
+		 * Verify that the userspace gave us a valid array for
+		 * plane information.
+		 */
+		ret = __verify_planes_array(vb, b);
+		if (ret)
+			return ret;
+
+		/* Fill in driver-provided information for OUTPUT types */
+		if (V4L2_TYPE_IS_OUTPUT(b->type)) {
+			/*
+			 * Will have to go up to b->length when API starts
+			 * accepting variable number of planes.
+			 */
+			for (plane = 0; plane < vb->num_planes; ++plane) {
+				v4l2_planes[plane].bytesused =
+					b->m.planes[plane].bytesused;
+				v4l2_planes[plane].data_offset =
+					b->m.planes[plane].data_offset;
+			}
+		}
+
+		if (b->memory == V4L2_MEMORY_USERPTR) {
+			for (plane = 0; plane < vb->num_planes; ++plane) {
+				v4l2_planes[plane].m.userptr =
+					b->m.planes[plane].m.userptr;
+				v4l2_planes[plane].length =
+					b->m.planes[plane].length;
+			}
+		}
+	} else {
+		/*
+		 * Single-planar buffers do not use planes array,
+		 * so fill in relevant v4l2_buffer struct fields instead.
+		 * In videobuf we use our internal V4l2_planes struct for
+		 * single-planar buffers as well, for simplicity.
+		 */
+		if (V4L2_TYPE_IS_OUTPUT(b->type))
+			v4l2_planes[0].bytesused = b->bytesused;
+
+		if (b->memory == V4L2_MEMORY_USERPTR) {
+			v4l2_planes[0].m.userptr = b->m.userptr;
+			v4l2_planes[0].length = b->length;
+		}
+	}
+
+	vb->v4l2_buf.field = b->field;
+	vb->v4l2_buf.timestamp = b->timestamp;
+
+	return 0;
+}
+
+/**
+ * __qbuf_userptr() - handle qbuf of a USERPTR buffer
+ */
+static int __qbuf_userptr(struct vb2_buffer *vb, struct v4l2_buffer *b)
+{
+	struct v4l2_plane planes[VIDEO_MAX_PLANES];
+	struct vb2_queue *q = vb->vb2_queue;
+	void *mem_priv;
+	unsigned int plane;
+	int ret;
+	int write = !V4L2_TYPE_IS_OUTPUT(q->type);
+
+	/* Verify and copy relevant information provided by the userspace */
+	ret = __fill_vb2_buffer(vb, b, planes);
+	if (ret)
+		return ret;
+
+	for (plane = 0; plane < vb->num_planes; ++plane) {
+		/* Skip the plane if already verified */
+		if (vb->v4l2_planes[plane].m.userptr == planes[plane].m.userptr
+		    && vb->v4l2_planes[plane].length == planes[plane].length)
+			continue;
+
+		dprintk(3, "qbuf: userspace address for plane %d changed, "
+				"reacquiring memory\n", plane);
+
+		/* Release previously acquired memory if present */
+		if (vb->planes[plane].mem_priv)
+			call_memop(q, plane, put_userptr,
+					vb->planes[plane].mem_priv);
+
+		vb->planes[plane].mem_priv = NULL;
+
+		/* Acquire each plane's memory */
+		if (q->mem_ops->get_userptr) {
+			mem_priv = q->mem_ops->get_userptr(q->alloc_ctx[plane],
+							planes[plane].m.userptr,
+							planes[plane].length,
+							write);
+			if (IS_ERR(mem_priv)) {
+				dprintk(1, "qbuf: failed acquiring userspace "
+						"memory for plane %d\n", plane);
+				goto err;
+			}
+			vb->planes[plane].mem_priv = mem_priv;
+		}
+	}
+
+	/*
+	 * Call driver-specific initialization on the newly acquired buffer,
+	 * if provided.
+	 */
+	ret = call_qop(q, buf_init, vb);
+	if (ret) {
+		dprintk(1, "qbuf: buffer initialization failed\n");
+		goto err;
+	}
+
+	/*
+	 * Now that everything is in order, copy relevant information
+	 * provided by userspace.
+	 */
+	for (plane = 0; plane < vb->num_planes; ++plane)
+		vb->v4l2_planes[plane] = planes[plane];
+
+	return 0;
+err:
+	/* In case of errors, release planes that were already acquired */
+	for (; plane > 0; --plane) {
+		call_memop(q, plane, put_userptr,
+				vb->planes[plane - 1].mem_priv);
+		vb->planes[plane - 1].mem_priv = NULL;
+	}
+
+	return ret;
+}
+
+/**
+ * __qbuf_mmap() - handle qbuf of an MMAP buffer
+ */
+static int __qbuf_mmap(struct vb2_buffer *vb, struct v4l2_buffer *b)
+{
+	return __fill_vb2_buffer(vb, b, vb->v4l2_planes);
+}
+
+/**
+ * __enqueue_in_driver() - enqueue a vb2_buffer in driver for processing
+ */
+static void __enqueue_in_driver(struct vb2_buffer *vb)
+{
+	struct vb2_queue *q = vb->vb2_queue;
+	vb->state = VB2_BUF_STATE_ACTIVE;
+	atomic_inc(&q->queued_count);
+	q->ops->buf_queue(vb);
+}
+
+/**
+ * vb2_qbuf() - Queue a buffer from userspace
+ * @q:		videobuf2 queue
+ * @b:		buffer structure passed from userspace to vidioc_qbuf handler
+ *		in driver
+ *
+ * Should be called from vidioc_qbuf ioctl handler of a driver.
+ * This function:
+ * 1) verifies the passed buffer,
+ * 2) calls buf_prepare callback in the driver (if provided), in which
+ *    driver-specific buffer initialization can be performed,
+ * 3) if streaming is on, queues the buffer in driver by the means of buf_queue
+ *    callback for processing.
+ *
+ * The return values from this function are intended to be directly returned
+ * from vidioc_qbuf handler in driver.
+ */
+int vb2_qbuf(struct vb2_queue *q, struct v4l2_buffer *b)
+{
+	struct vb2_buffer *vb;
+	int ret = 0;
+
+	if (b->type != q->type) {
+		dprintk(1, "qbuf: invalid buffer type\n");
+		return -EINVAL;
+	}
+
+	if (b->index >= q->num_buffers) {
+		dprintk(1, "qbuf: buffer index out of range\n");
+		return -EINVAL;
+	}
+
+	vb = q->bufs[b->index];
+	if (NULL == vb) {
+		/* Should never happen */
+		dprintk(1, "qbuf: buffer is NULL\n");
+		return -EINVAL;
+	}
+
+	if (b->memory != q->memory) {
+		dprintk(1, "qbuf: invalid memory type\n");
+		return -EINVAL;
+	}
+
+	if (vb->state != VB2_BUF_STATE_DEQUEUED) {
+		dprintk(1, "qbuf: buffer already in use\n");
+		return -EINVAL;
+	}
+
+	if (q->memory == V4L2_MEMORY_MMAP)
+		ret = __qbuf_mmap(vb, b);
+	else if (q->memory == V4L2_MEMORY_USERPTR)
+		ret = __qbuf_userptr(vb, b);
+	else
+		BUG();
+
+	if (ret)
+		return ret;
+
+	ret = call_qop(q, buf_prepare, vb);
+	if (ret) {
+		dprintk(1, "qbuf: buffer preparation failed\n");
+		return ret;
+	}
+
+	/*
+	 * Add to the queued buffers list, a buffer will stay on it until
+	 * dequeued in dqbuf.
+	 */
+	list_add_tail(&vb->queued_entry, &q->queued_list);
+	vb->state = VB2_BUF_STATE_QUEUED;
+
+	/*
+	 * If already streaming, give the buffer to driver for processing.
+	 * If not, the buffer will be given to driver on next streamon.
+	 */
+	if (q->streaming)
+		__enqueue_in_driver(vb);
+
+	dprintk(1, "qbuf of buffer %d succeeded\n", vb->v4l2_buf.index);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(vb2_qbuf);
+
+/**
+ * __vb2_wait_for_done_vb() - wait for a buffer to become available
+ * for dequeuing
+ *
+ * Will sleep if required for nonblocking == false.
+ */
+static int __vb2_wait_for_done_vb(struct vb2_queue *q, int nonblocking)
+{
+	/*
+	 * All operation on vb_done_list is performed under vb_done_lock
+	 * spinlock protection. However buffers may must be removed from
+	 * it and returned to userspace only while holding both driver's
+	 * lock and the vb_done_lock spinlock. Thus we can be sure that as
+	 * long as we hold lock, the list will remain not empty if this
+	 * check succeeds.
+	 */
+
+	for (;;) {
+		int ret;
+
+		if (!q->streaming) {
+			dprintk(1, "Streaming off, will not wait for buffers\n");
+			return -EINVAL;
+		}
+
+		if (!list_empty(&q->done_list)) {
+			/*
+			 * Found a buffer that we were waiting for.
+			 */
+			break;
+		} else if (nonblocking) {
+			dprintk(1, "Nonblocking and no buffers to dequeue, "
+								"will not wait\n");
+			return -EAGAIN;
+		}
+
+		/*
+		 * We are streaming and blocking, wait for another buffer to
+		 * become ready or for streamoff. Driver's lock is released to
+		 * allow streamoff or qbuf to be called while waiting.
+		 */
+		call_qop(q, wait_prepare, q);
+
+		/*
+		 * All locks has been released, it is safe to sleep now.
+		 */
+		dprintk(3, "Will sleep waiting for buffers\n");
+		ret = wait_event_interruptible(q->done_wq,
+				!list_empty(&q->done_list) || !q->streaming);
+
+		/*
+		 * We need to reevaluate both conditions again after reacquiring
+		 * the locks or return an error if it occured. In case of error
+		 * we return -EINTR, because -ERESTARTSYS should not be returned
+		 * to userspace.
+		 */
+		call_qop(q, wait_finish, q);
+		if (ret)
+			return -EINTR;
+	}
+	return 0;
+}
+
+/**
+ * __vb2_get_done_vb() - get a buffer ready for dequeuing
+ *
+ * Will sleep if required for nonblocking == false.
+ */
+static int __vb2_get_done_vb(struct vb2_queue *q, struct vb2_buffer **vb,
+				int nonblocking)
+{
+	unsigned long flags;
+	int ret;
+
+	/*
+	 * Wait for at least one buffer to become available on the done_list.
+	 */
+	ret = __vb2_wait_for_done_vb(q, nonblocking);
+	if (ret)
+		return ret;
+
+	/*
+	 * Drivers lock has been held since we last verified that done_list is
+	 * not empty, so no need for another list_empty(done_list) check.
+	 */
+	spin_lock_irqsave(&q->done_lock, flags);
+	*vb = list_first_entry(&q->done_list, struct vb2_buffer, done_entry);
+	list_del(&(*vb)->done_entry);
+	spin_unlock_irqrestore(&q->done_lock, flags);
+
+	return 0;
+}
+
+/**
+ * vb2_wait_for_all_buffers() - wait until all buffers will be given back to vb2
+ * @q:		videobuf2 queue
+ *
+ * This function will wait until all buffers that have been given to the driver
+ * by buf_queue() are given back to vb2 with vb2_buffer_done(). It doesn't call
+ * wait_prepare, wait_finish pair. It is intended to call it with all locks
+ * taken, from stop_steaming() callback.
+ */
+int vb2_wait_for_all_buffers(struct vb2_queue *q)
+{
+	if (!q->streaming) {
+		dprintk(1, "Streaming off, will not wait for buffers\n");
+		return -EINVAL;
+	}
+
+	wait_event(q->done_wq, !atomic_read(&q->queued_count));
+	return 0;
+}
+EXPORT_SYMBOL_GPL(vb2_wait_for_all_buffers);
+
+/**
+ * vb2_dqbuf() - Dequeue a buffer to the userspace
+ * @q:		videobuf2 queue
+ * @b:		buffer structure passed from userspace to vidioc_dqbuf handler
+ *		in driver
+ * @nonblocking: if true, this call will not sleep waiting for a buffer if no
+ *		 buffers ready for dequeuing are present. Normally the driver
+ *		 would be passing (file->f_flags & O_NONBLOCK) here
+ *
+ * Should be called from vidioc_dqbuf ioctl handler of a driver.
+ * This function:
+ * 1) verifies the passed buffer,
+ * 2) calls buf_finish callback in the driver (if provided), in which
+ *    driver can perform any additional operations that may be required before
+ *    returning the buffer to userspace, such as cache sync,
+ * 3) the buffer struct members are filled with relevant information for
+ *    the userspace.
+ *
+ * The return values from this function are intended to be directly returned
+ * from vidioc_dqbuf handler in driver.
+ */
+int vb2_dqbuf(struct vb2_queue *q, struct v4l2_buffer *b, bool nonblocking)
+{
+	struct vb2_buffer *vb = NULL;
+	int ret;
+
+	if (b->type != q->type) {
+		dprintk(1, "dqbuf: invalid buffer type\n");
+		return -EINVAL;
+	}
+
+	ret = __vb2_get_done_vb(q, &vb, nonblocking);
+	if (ret < 0) {
+		dprintk(1, "dqbuf: error getting next done buffer\n");
+		return ret;
+	}
+
+	ret = call_qop(q, buf_finish, vb);
+	if (ret) {
+		dprintk(1, "dqbuf: buffer finish failed\n");
+		return ret;
+	}
+
+	switch (vb->state) {
+	case VB2_BUF_STATE_DONE:
+		dprintk(3, "dqbuf: Returning done buffer\n");
+		break;
+	case VB2_BUF_STATE_ERROR:
+		dprintk(3, "dqbuf: Returning done buffer with errors\n");
+		break;
+	default:
+		dprintk(1, "dqbuf: Invalid buffer state\n");
+		return -EINVAL;
+	}
+
+	/* Fill buffer information for the userspace */
+	__fill_v4l2_buffer(vb, b);
+	/* Remove from videobuf queue */
+	list_del(&vb->queued_entry);
+
+	dprintk(1, "dqbuf of buffer %d, with state %d\n",
+			vb->v4l2_buf.index, vb->state);
+
+	vb->state = VB2_BUF_STATE_DEQUEUED;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(vb2_dqbuf);
+
+/**
+ * vb2_streamon - start streaming
+ * @q:		videobuf2 queue
+ * @type:	type argument passed from userspace to vidioc_streamon handler
+ *
+ * Should be called from vidioc_streamon handler of a driver.
+ * This function:
+ * 1) verifies current state
+ * 2) starts streaming and passes any previously queued buffers to the driver
+ *
+ * The return values from this function are intended to be directly returned
+ * from vidioc_streamon handler in the driver.
+ */
+int vb2_streamon(struct vb2_queue *q, enum v4l2_buf_type type)
+{
+	struct vb2_buffer *vb;
+
+	if (type != q->type) {
+		dprintk(1, "streamon: invalid stream type\n");
+		return -EINVAL;
+	}
+
+	if (q->streaming) {
+		dprintk(1, "streamon: already streaming\n");
+		return -EBUSY;
+	}
+
+	/*
+	 * Cannot start streaming on an OUTPUT device if no buffers have
+	 * been queued yet.
+	 */
+	if (V4L2_TYPE_IS_OUTPUT(q->type)) {
+		if (list_empty(&q->queued_list)) {
+			dprintk(1, "streamon: no output buffers queued\n");
+			return -EINVAL;
+		}
+	}
+
+	q->streaming = 1;
+
+	/*
+	 * Let driver notice that streaming state has been enabled.
+	 */
+	call_qop(q, start_streaming, q);
+
+	/*
+	 * If any buffers were queued before streamon,
+	 * we can now pass them to driver for processing.
+	 */
+	list_for_each_entry(vb, &q->queued_list, queued_entry)
+		__enqueue_in_driver(vb);
+
+	dprintk(3, "Streamon successful\n");
+	return 0;
+}
+EXPORT_SYMBOL_GPL(vb2_streamon);
+
+/**
+ * __vb2_queue_cancel() - cancel and stop (pause) streaming
+ *
+ * Removes all queued buffers from driver's queue and all buffers queued by
+ * userspace from videobuf's queue. Returns to state after reqbufs.
+ */
+static void __vb2_queue_cancel(struct vb2_queue *q)
+{
+	unsigned int i;
+
+	/*
+	 * Tell driver to stop all transactions and release all queued
+	 * buffers.
+	 */
+	if (q->streaming)
+		call_qop(q, stop_streaming, q);
+	q->streaming = 0;
+
+	/*
+	 * Remove all buffers from videobuf's list...
+	 */
+	INIT_LIST_HEAD(&q->queued_list);
+	/*
+	 * ...and done list; userspace will not receive any buffers it
+	 * has not already dequeued before initiating cancel.
+	 */
+	INIT_LIST_HEAD(&q->done_list);
+	wake_up_all(&q->done_wq);
+
+	/*
+	 * Reinitialize all buffers for next use.
+	 */
+	for (i = 0; i < q->num_buffers; ++i)
+		q->bufs[i]->state = VB2_BUF_STATE_DEQUEUED;
+}
+
+/**
+ * vb2_streamoff - stop streaming
+ * @q:		videobuf2 queue
+ * @type:	type argument passed from userspace to vidioc_streamoff handler
+ *
+ * Should be called from vidioc_streamoff handler of a driver.
+ * This function:
+ * 1) verifies current state,
+ * 2) stop streaming and dequeues any queued buffers, including those previously
+ *    passed to the driver (after waiting for the driver to finish).
+ *
+ * This call can be used for pausing playback.
+ * The return values from this function are intended to be directly returned
+ * from vidioc_streamoff handler in the driver
+ */
+int vb2_streamoff(struct vb2_queue *q, enum v4l2_buf_type type)
+{
+	if (type != q->type) {
+		dprintk(1, "streamoff: invalid stream type\n");
+		return -EINVAL;
+	}
+
+	if (!q->streaming) {
+		dprintk(1, "streamoff: not streaming\n");
+		return -EINVAL;
+	}
+
+	/*
+	 * Cancel will pause streaming and remove all buffers from the driver
+	 * and videobuf, effectively returning control over them to userspace.
+	 */
+	__vb2_queue_cancel(q);
+
+	dprintk(3, "Streamoff successful\n");
+	return 0;
+}
+EXPORT_SYMBOL_GPL(vb2_streamoff);
+
+/**
+ * __find_plane_by_offset() - find plane associated with the given offset off
+ */
+static int __find_plane_by_offset(struct vb2_queue *q, unsigned long off,
+			unsigned int *_buffer, unsigned int *_plane)
+{
+	struct vb2_buffer *vb;
+	unsigned int buffer, plane;
+
+	/*
+	 * Go over all buffers and their planes, comparing the given offset
+	 * with an offset assigned to each plane. If a match is found,
+	 * return its buffer and plane numbers.
+	 */
+	for (buffer = 0; buffer < q->num_buffers; ++buffer) {
+		vb = q->bufs[buffer];
+
+		for (plane = 0; plane < vb->num_planes; ++plane) {
+			if (vb->v4l2_planes[plane].m.mem_offset == off) {
+				*_buffer = buffer;
+				*_plane = plane;
+				return 0;
+			}
+		}
+	}
+
+	return -EINVAL;
+}
+
+/**
+ * vb2_mmap() - map video buffers into application address space
+ * @q:		videobuf2 queue
+ * @vma:	vma passed to the mmap file operation handler in the driver
+ *
+ * Should be called from mmap file operation handler of a driver.
+ * This function maps one plane of one of the available video buffers to
+ * userspace. To map whole video memory allocated on reqbufs, this function
+ * has to be called once per each plane per each buffer previously allocated.
+ *
+ * When the userspace application calls mmap, it passes to it an offset returned
+ * to it earlier by the means of vidioc_querybuf handler. That offset acts as
+ * a "cookie", which is then used to identify the plane to be mapped.
+ * This function finds a plane with a matching offset and a mapping is performed
+ * by the means of a provided memory operation.
+ *
+ * The return values from this function are intended to be directly returned
+ * from the mmap handler in driver.
+ */
+int vb2_mmap(struct vb2_queue *q, struct vm_area_struct *vma)
+{
+	unsigned long off = vma->vm_pgoff << PAGE_SHIFT;
+	struct vb2_plane *vb_plane;
+	struct vb2_buffer *vb;
+	unsigned int buffer, plane;
+	int ret = -EINVAL;
+
+	if (q->memory != V4L2_MEMORY_MMAP) {
+		dprintk(1, "Queue is not currently set up for mmap\n");
+		return -EINVAL;
+	}
+
+	/*
+	 * Check memory area access mode.
+	 */
+	if (!(vma->vm_flags & VM_SHARED)) {
+		dprintk(1, "Invalid vma flags, VM_SHARED needed\n");
+		return -EINVAL;
+	}
+	if (V4L2_TYPE_IS_OUTPUT(q->type)) {
+		if (!(vma->vm_flags & (VM_WRITE))) {
+			dprintk(1, "Invalid vma flags, VM_WRITE needed\n");
+			return -EINVAL;
+		}
+	} else {
+		if (!(vma->vm_flags & VM_READ)) {
+			dprintk(1, "Invalid vma flags, VM_READ needed\n");
+			return -EINVAL;
+		}
+	}
+
+	/*
+	 * Find the plane corresponding to the offset passed by userspace.
+	 */
+	ret = __find_plane_by_offset(q, off, &buffer, &plane);
+	if (ret)
+		return ret;
+
+	vb = q->bufs[buffer];
+	vb_plane = &vb->planes[plane];
+
+	ret = q->mem_ops->mmap(vb_plane->mem_priv, vma);
+	if (ret)
+		return ret;
+
+	vb_plane->mapped = 1;
+	vb->num_planes_mapped++;
+
+	dprintk(3, "Buffer %d, plane %d successfully mapped\n", buffer, plane);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(vb2_mmap);
+
+
+/**
+ * vb2_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_poll(struct vb2_queue *q, struct file *file, poll_table *wait)
+{
+	unsigned long flags;
+	struct vb2_buffer *vb = NULL;
+
+	/*
+	 * There is nothing to wait for if no buffers have already been queued.
+	 */
+	if (list_empty(&q->queued_list))
+		return POLLERR;
+
+	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)) {
+		if (V4L2_TYPE_IS_OUTPUT(q->type))
+			return POLLOUT | POLLWRNORM;
+		else
+			return POLLIN | POLLRDNORM;
+	}
+	return 0;
+}
+EXPORT_SYMBOL_GPL(vb2_poll);
+
+/**
+ * vb2_queue_init() - initialize a videobuf2 queue
+ * @q:		videobuf2 queue; this structure should be allocated in driver
+ * @ops:	driver-specific callbacks
+ * @alloc_ctx:	memory handler/allocator-specific context to be used;
+ *		the given context will be used for memory allocation on all
+ *		planes and buffers; it is possible to assign different contexts
+ *		per plane, use vb2_set_alloc_ctx() for that
+ * @type:	queue type
+ * @drv_priv:	driver private data, may be NULL; it can be used by driver in
+ *		driver-specific callbacks when issued
+ */
+int vb2_queue_init(struct vb2_queue *q)
+{
+	BUG_ON(!q);
+	BUG_ON(!q->ops);
+	BUG_ON(!q->mem_ops);
+	BUG_ON(!q->io_modes);
+
+	BUG_ON(!q->ops->queue_setup);
+	BUG_ON(!q->ops->buf_queue);
+
+	INIT_LIST_HEAD(&q->queued_list);
+	INIT_LIST_HEAD(&q->done_list);
+	spin_lock_init(&q->done_lock);
+	init_waitqueue_head(&q->done_wq);
+
+	if (q->buf_struct_size == 0)
+		q->buf_struct_size = sizeof(struct vb2_buffer);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(vb2_queue_init);
+
+/**
+ * vb2_queue_release() - stop streaming, release the queue and free memory
+ * @q:		videobuf2 queue
+ *
+ * This function stops streaming and performs necessary clean ups, including
+ * freeing video buffer memory. The driver is responsible for freeing
+ * the vb2_queue structure itself.
+ */
+void vb2_queue_release(struct vb2_queue *q)
+{
+	__vb2_queue_cancel(q);
+	__vb2_queue_free(q);
+}
+EXPORT_SYMBOL_GPL(vb2_queue_release);
+
+MODULE_DESCRIPTION("Driver helper framework for Video for Linux 2");
+MODULE_AUTHOR("Pawel Osciak, Marek Szyprowski");
+MODULE_LICENSE("GPL");
diff --git a/include/media/videobuf2-core.h b/include/media/videobuf2-core.h
new file mode 100644
index 0000000..61814fc
--- /dev/null
+++ b/include/media/videobuf2-core.h
@@ -0,0 +1,368 @@ 
+/*
+ * videobuf2-core.h - V4L2 driver helper framework
+ *
+ * Copyright (C) 2010 Samsung Electronics
+ *
+ * Author: Pawel Osciak <p.osciak@samsung.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation.
+ */
+#ifndef _MEDIA_VIDEOBUF2_CORE_H
+#define _MEDIA_VIDEOBUF2_CORE_H
+
+#include <linux/mm_types.h>
+#include <linux/mutex.h>
+#include <linux/poll.h>
+#include <linux/videodev2.h>
+
+struct vb2_alloc_ctx;
+
+/**
+ * struct vb2_mem_ops - memory handling/memory allocator operations
+ * @alloc:	allocate video memory and, optionally, allocator private data,
+ *		return NULL on failure or a pointer to allocator private,
+ *		per-buffer data on success; the returned private structure
+ *		will then be passed as buf_priv argument to other ops in this
+ *		structure
+ * @put:	inform the allocator that the buffer will no longer be used;
+ *		usually will result in the allocator freeing the buffer (if
+ *		no other users of this buffer are present); the buf_priv
+ *		argument is the allocator private per-buffer structure
+ *		previously returned from the alloc callback
+ * @get_userptr: acquire userspace memory for a hardware operation; used for
+ *		 USERPTR memory types; vaddr is the address passed to the
+ *		 videobuf layer when queuing a video buffer of USERPTR type;
+ *		 should return an allocator private per-buffer structure
+ *		 associated with the buffer on success, NULL on failure;
+ *		 the returned private structure will then be passed as buf_priv
+ *		 argument to other ops in this structure
+ * @put_userptr: inform the allocator that a USERPTR buffer will no longer
+ *		 be used
+ * @vaddr:	return a kernel virtual address to a given memory buffer
+ *		associated with the passed private structure or NULL if no
+ *		such mapping exists
+ * @cookie:	return allocator specific cookie for a given memory buffer
+ *		associated with the passed private structure or NULL if not
+ *		available
+ * @num_users:	return the current number of users of a memory buffer;
+ *		return 1 if the videobuf layer (or actually the driver using
+ *		it) is the only user
+ * @mmap:	setup a userspace mapping for a given memory buffer under
+ *		the provided virtual memory region
+ *
+ * Required ops for USERPTR types: get_userptr, put_userptr.
+ * Required ops for MMAP types: alloc, put, num_users, mmap.
+ */
+struct vb2_mem_ops {
+	void		*(*alloc)(void *alloc_ctx, unsigned long size);
+	void		(*put)(void *buf_priv);
+
+	void		*(*get_userptr)(void *alloc_ctx, unsigned long vaddr,
+					unsigned long size, int write);
+	void		(*put_userptr)(void *buf_priv);
+
+	void		*(*vaddr)(void *buf_priv);
+	void		*(*cookie)(void *buf_priv);
+
+	unsigned int	(*num_users)(void *buf_priv);
+
+	int		(*mmap)(void *buf_priv, struct vm_area_struct *vma);
+};
+
+struct vb2_plane {
+	void			*mem_priv;
+	int			mapped:1;
+};
+
+/**
+ * enum vb2_io_modes - queue access methods
+ * @VB2_MMAP:		driver supports MMAP with streaming api
+ * @VB2_USERPTR:	driver supports USERPTR with streaming api
+ * @VB2_READ:		driver supports read() style access
+ * @VB2_WRITE:		driver supports write() style access
+ */
+enum vb2_io_modes {
+	VB2_MMAP	= (1 << 0),
+	VB2_USERPTR	= (1 << 1),
+	VB2_READ	= (1 << 2),
+	VB2_WRITE	= (1 << 3),
+};
+
+/**
+ * enum vb2_fileio_flags - flags for selecting a mode of the file io emulator,
+ * by default the 'streaming' style is used by the file io emulator
+ * @VB2_FILEIO_READ_ONCE:	report EOF after reading the first buffer
+ * @VB2_FILEIO_WRITE_IMMEDIATE:	queue buffer after each write() call
+ */
+enum vb2_fileio_flags {
+	VB2_FILEIO_READ_ONCE		= (1 << 0),
+	VB2_FILEIO_WRITE_IMMEDIATE	= (1 << 1),
+};
+
+/**
+ * enum vb2_buffer_state - current video buffer state
+ * @VB2_BUF_STATE_DEQUEUED:	buffer under userspace control
+ * @VB2_BUF_STATE_QUEUED:	buffer queued in videobuf, but not in driver
+ * @VB2_BUF_STATE_ACTIVE:	buffer queued in driver and possibly used
+ *				in a hardware operation
+ * @VB2_BUF_STATE_DONE:		buffer returned from driver to videobuf, but
+ *				not yet dequeued to userspace
+ * @VB2_BUF_STATE_ERROR:	same as above, but the operation on the buffer
+ *				has ended with an error, which will be reported
+ *				to the userspace when it is dequeued
+ */
+enum vb2_buffer_state {
+	VB2_BUF_STATE_DEQUEUED,
+	VB2_BUF_STATE_QUEUED,
+	VB2_BUF_STATE_ACTIVE,
+	VB2_BUF_STATE_DONE,
+	VB2_BUF_STATE_ERROR,
+};
+
+struct vb2_queue;
+
+/**
+ * struct vb2_buffer - represents a video buffer
+ * @v4l2_buf:		struct v4l2_buffer associated with this buffer; can
+ *			be read by the driver and relevant entries can be
+ *			changed by the driver in case of CAPTURE types
+ *			(such as timestamp)
+ * @v4l2_planes:	struct v4l2_planes associated with this buffer; can
+ *			be read by the driver and relevant entries can be
+ *			changed by the driver in case of CAPTURE types
+ *			(such as bytesused); NOTE that even for single-planar
+ *			types, the v4l2_planes[0] struct should be used
+ *			instead of v4l2_buf for filling bytesused - drivers
+ *			should use the vb2_set_plane_payload() function for that
+ * @vb2_queue:		the queue to which this driver belongs
+ * @drv_entry:		list entry to be used by driver for storing the buffer
+ * @num_planes:		number of planes in the buffer
+ *			on an internal driver queue
+ * @state:		current buffer state; do not change
+ * @queued_entry:	entry on the queued buffers list, which holds all
+ *			buffers queued from userspace
+ * @done_entry:		entry on the list that stores all buffers ready to
+ *			be dequeued to userspace
+ * @planes:		private per-plane information; do not change
+ * @num_planes_mapped:	number of mapped planes; do not change
+ */
+struct vb2_buffer {
+	struct v4l2_buffer	v4l2_buf;
+	struct v4l2_plane	v4l2_planes[VIDEO_MAX_PLANES];
+
+	struct vb2_queue	*vb2_queue;
+
+	unsigned int		num_planes;
+
+/* Private: internal use only */
+	enum vb2_buffer_state	state;
+
+	struct list_head	queued_entry;
+	struct list_head	done_entry;
+
+	struct vb2_plane	planes[VIDEO_MAX_PLANES];
+	unsigned int		num_planes_mapped;
+};
+
+/**
+ * struct vb2_ops - driver-specific callbacks
+ *
+ * @queue_setup:	called from a VIDIOC_REQBUFS handler, before
+ *			memory allocation; driver should return the required
+ *			number of buffers in num_buffers, the required number
+ *			of planes per buffer in num_planes and the required
+ *			sizes of planes in size_planes array
+ * @wait_prepare:	release any locks taken while calling vb2 functions;
+ *			it is called before poll_wait function in vb2_poll
+ *			implementation; required to avoid deadlock when vb2_poll
+ *			function waits for a buffer
+ * @wait_finish:	reacquire all locks released in the previous callback;
+ *			required to continue operation after sleeping in
+ *			poll_wait function
+ * @buf_init:		called once after allocating a buffer (in MMAP case)
+ *			or after acquiring a new USERPTR buffer; drivers may
+ *			perform additional buffer-related initialization;
+ *			initialization failure (return != 0) will prevent
+ *			queue setup from completing successfully; optional
+ * @buf_prepare:	called every time the buffer is queued from userspace;
+ *			drivers may perform any initialization required before
+ *			each hardware operation in this callback;
+ *			if an error is returned, the buffer will not be queued
+ *			in driver; optional
+ * @buf_finish:		called before every dequeue of the buffer back to
+ *			userspace; drivers may perform any operations required
+ *			before userspace accesses the buffer; optional
+ * @buf_cleanup:	called once before the buffer is freed; drivers may
+ *			perform any additional cleanup; optional
+ * @start_streaming:	called once before entering 'streaming' state; enables
+ *			driver to recieve buffers over buf_queue() callback
+ * @stop_streaming:	called when 'streaming' state must be disabled; driver
+ *			should stop any dma transactions or wait until they
+ *			finish and give back all buffers it got from buf_queue()
+ *			callback
+ * @buf_queue:		passes buffer vb to the driver; driver may start
+ *			hardware operation on this buffer; driver should give
+ *			the buffer back by calling vb2_buffer_done() function
+ */
+struct vb2_ops {
+	int (*queue_setup)(struct vb2_queue *q, unsigned int *num_buffers,
+			   unsigned int *num_planes, unsigned long sizes[],
+			   void *alloc_ctxs[]);
+
+	void (*wait_prepare)(struct vb2_queue *q);
+	void (*wait_finish)(struct vb2_queue *q);
+
+	int (*buf_init)(struct vb2_buffer *vb);
+	int (*buf_prepare)(struct vb2_buffer *vb);
+	int (*buf_finish)(struct vb2_buffer *vb);
+	void (*buf_cleanup)(struct vb2_buffer *vb);
+
+	int (*start_streaming)(struct vb2_queue *q);
+	int (*stop_streaming)(struct vb2_queue *q);
+
+	void (*buf_queue)(struct vb2_buffer *vb);
+};
+
+/**
+ * struct vb2_queue - a videobuf queue
+ *
+ * @type:	queue type (see V4L2_BUF_TYPE_* in linux/videodev2.h
+ * @io_modes:	supported io methods (see vb2_io_modes enum)
+ * @io_flags:	additional io flags
+ * @ops:	driver-specific callbacks
+ * @mem_ops:	memory allocator specific callbacks
+ * @drv_priv:	driver private data
+ * @buf_struct_size: size of the driver specific buffer structure
+ *
+ * @memory:	current memory type used
+ * @bufs:	videobuf buffer structures
+ * @num_buffers: number of allocated/used buffers
+ * @queued_list: list of buffers currently queued from userspace
+ * @queued_count: number of buffers owned by the driver
+ * @done_list:	list of buffers ready to be dequeued to userspace
+ * @done_lock:	lock to protect done_list list
+ * @done_wq:	waitqueue for processes waiting for buffers ready to be dequeued
+ * @alloc_ctx:	memory type/allocator-specific contexts for each plane
+ * @streaming:	current streaming state
+ */
+struct vb2_queue {
+	enum v4l2_buf_type		type;
+	unsigned int			io_modes;
+	unsigned int			io_flags;
+
+	const struct vb2_ops		*ops;
+	const struct vb2_mem_ops	*mem_ops;
+	void				*drv_priv;
+	unsigned int			buf_struct_size;
+
+/* private: internal use only */
+	enum v4l2_memory		memory;
+	struct vb2_buffer		*bufs[VIDEO_MAX_FRAME];
+	unsigned int			num_buffers;
+
+	struct list_head		queued_list;
+
+	atomic_t			queued_count;
+	struct list_head		done_list;
+	spinlock_t			done_lock;
+	wait_queue_head_t		done_wq;
+
+	void				*alloc_ctx[VIDEO_MAX_PLANES];
+
+	unsigned int			streaming:1;
+};
+
+void *vb2_plane_vaddr(struct vb2_buffer *vb, unsigned int plane_no);
+void *vb2_plane_cookie(struct vb2_buffer *vb, unsigned int plane_no);
+
+void vb2_buffer_done(struct vb2_buffer *vb, enum vb2_buffer_state state);
+int vb2_wait_for_all_buffers(struct vb2_queue *q);
+
+int vb2_querybuf(struct vb2_queue *q, struct v4l2_buffer *b);
+int vb2_reqbufs(struct vb2_queue *q, struct v4l2_requestbuffers *req);
+
+int vb2_queue_init(struct vb2_queue *q);
+
+void vb2_queue_release(struct vb2_queue *q);
+
+int vb2_qbuf(struct vb2_queue *q, struct v4l2_buffer *b);
+int vb2_dqbuf(struct vb2_queue *q, struct v4l2_buffer *b, bool nonblocking);
+
+int vb2_streamon(struct vb2_queue *q, enum v4l2_buf_type type);
+int vb2_streamoff(struct vb2_queue *q, enum v4l2_buf_type type);
+
+int vb2_mmap(struct vb2_queue *q, struct vm_area_struct *vma);
+unsigned int vb2_poll(struct vb2_queue *q, struct file *file, poll_table *wait);
+
+/**
+ * vb2_is_streaming() - return streaming status of the queue
+ * @q:		videobuf queue
+ */
+static inline bool vb2_is_streaming(struct vb2_queue *q)
+{
+	return q->streaming;
+}
+
+/**
+ * vb2_is_busy() - return busy status of the queue
+ * @q:		videobuf queue
+ *
+ * This function checks if queue has any buffers allocated.
+ */
+static inline bool vb2_is_busy(struct vb2_queue *q)
+{
+	return (q->num_buffers > 0);
+}
+
+/**
+ * vb2_get_drv_priv() - return driver private data associated with the queue
+ * @q:		videobuf queue
+ */
+static inline void *vb2_get_drv_priv(struct vb2_queue *q)
+{
+	return q->drv_priv;
+}
+
+/**
+ * vb2_set_plane_payload() - set bytesused for the plane plane_no
+ * @vb:		buffer for which plane payload should be set
+ * @plane_no:	plane number for which payload should be set
+ * @size:	payload in bytes
+ */
+static inline void vb2_set_plane_payload(struct vb2_buffer *vb,
+				 unsigned int plane_no, unsigned long size)
+{
+	if (plane_no < vb->num_planes)
+		vb->v4l2_planes[plane_no].bytesused = size;
+}
+
+/**
+ * vb2_get_plane_payload() - set bytesused for the plane plane_no
+ * @vb:		buffer for which plane payload should be set
+ * @plane_no:	plane number for which payload should be set
+ * @size:	payload in bytes
+ */
+static inline unsigned long vb2_get_plane_payload(struct vb2_buffer *vb,
+				 unsigned int plane_no)
+{
+	if (plane_no < vb->num_planes)
+		return vb->v4l2_planes[plane_no].bytesused;
+	return 0;
+}
+
+/**
+ * vb2_plane_size() - return plane size in bytes
+ * @vb:		buffer for which plane size should be returned
+ * @plane_no:	plane number for which size should be returned
+ */
+static inline unsigned long
+vb2_plane_size(struct vb2_buffer *vb, unsigned int plane_no)
+{
+	if (plane_no < vb->num_planes)
+		return vb->v4l2_planes[plane_no].length;
+	return 0;
+}
+
+#endif /* _MEDIA_VIDEOBUF2_CORE_H */