2 * videobuf2-core.c - V4L2 driver helper framework
4 * Copyright (C) 2010 Samsung Electronics
6 * Author: Pawel Osciak <pawel@osciak.com>
7 * Marek Szyprowski <m.szyprowski@samsung.com>
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License as published by
11 * the Free Software Foundation.
14 #include <linux/err.h>
15 #include <linux/kernel.h>
16 #include <linux/module.h>
18 #include <linux/poll.h>
19 #include <linux/slab.h>
20 #include <linux/sched.h>
22 #include <media/v4l2-dev.h>
23 #include <media/v4l2-fh.h>
24 #include <media/v4l2-event.h>
25 #include <media/videobuf2-core.h>
28 module_param(debug, int, 0644);
30 #define dprintk(level, fmt, arg...) \
33 printk(KERN_DEBUG "vb2: " fmt, ## arg); \
36 #define call_memop(q, op, args...) \
37 (((q)->mem_ops->op) ? \
38 ((q)->mem_ops->op(args)) : 0)
40 #define call_qop(q, op, args...) \
41 (((q)->ops->op) ? ((q)->ops->op(args)) : 0)
43 #define V4L2_BUFFER_STATE_FLAGS (V4L2_BUF_FLAG_MAPPED | V4L2_BUF_FLAG_QUEUED | \
44 V4L2_BUF_FLAG_DONE | V4L2_BUF_FLAG_ERROR | \
45 V4L2_BUF_FLAG_PREPARED)
48 * __vb2_buf_mem_alloc() - allocate video memory for the given buffer
50 static int __vb2_buf_mem_alloc(struct vb2_buffer *vb)
52 struct vb2_queue *q = vb->vb2_queue;
56 /* Allocate memory for all planes in this buffer */
57 for (plane = 0; plane < vb->num_planes; ++plane) {
58 mem_priv = call_memop(q, alloc, q->alloc_ctx[plane],
59 q->plane_sizes[plane]);
60 if (IS_ERR_OR_NULL(mem_priv))
63 /* Associate allocator private data with this plane */
64 vb->planes[plane].mem_priv = mem_priv;
65 vb->v4l2_planes[plane].length = q->plane_sizes[plane];
70 /* Free already allocated memory if one of the allocations failed */
71 for (; plane > 0; --plane) {
72 call_memop(q, put, vb->planes[plane - 1].mem_priv);
73 vb->planes[plane - 1].mem_priv = NULL;
80 * __vb2_buf_mem_free() - free memory of the given buffer
82 static void __vb2_buf_mem_free(struct vb2_buffer *vb)
84 struct vb2_queue *q = vb->vb2_queue;
87 for (plane = 0; plane < vb->num_planes; ++plane) {
88 call_memop(q, put, vb->planes[plane].mem_priv);
89 vb->planes[plane].mem_priv = NULL;
90 dprintk(3, "Freed plane %d of buffer %d\n", plane,
96 * __vb2_buf_userptr_put() - release userspace memory associated with
99 static void __vb2_buf_userptr_put(struct vb2_buffer *vb)
101 struct vb2_queue *q = vb->vb2_queue;
104 for (plane = 0; plane < vb->num_planes; ++plane) {
105 if (vb->planes[plane].mem_priv)
106 call_memop(q, put_userptr, vb->planes[plane].mem_priv);
107 vb->planes[plane].mem_priv = NULL;
112 * __setup_offsets() - setup unique offsets ("cookies") for every plane in
113 * every buffer on the queue
115 static void __setup_offsets(struct vb2_queue *q, unsigned int n)
117 unsigned int buffer, plane;
118 struct vb2_buffer *vb;
121 if (q->num_buffers) {
122 struct v4l2_plane *p;
123 vb = q->bufs[q->num_buffers - 1];
124 p = &vb->v4l2_planes[vb->num_planes - 1];
125 off = PAGE_ALIGN(p->m.mem_offset + p->length);
130 for (buffer = q->num_buffers; buffer < q->num_buffers + n; ++buffer) {
131 vb = q->bufs[buffer];
135 for (plane = 0; plane < vb->num_planes; ++plane) {
136 vb->v4l2_planes[plane].length = q->plane_sizes[plane];
137 vb->v4l2_planes[plane].m.mem_offset = off;
139 dprintk(3, "Buffer %d, plane %d offset 0x%08lx\n",
142 off += vb->v4l2_planes[plane].length;
143 off = PAGE_ALIGN(off);
149 * __vb2_queue_alloc() - allocate videobuf buffer structures and (for MMAP type)
150 * video buffer memory for all buffers/planes on the queue and initializes the
153 * Returns the number of buffers successfully allocated.
155 static int __vb2_queue_alloc(struct vb2_queue *q, enum v4l2_memory memory,
156 unsigned int num_buffers, unsigned int num_planes)
159 struct vb2_buffer *vb;
162 for (buffer = 0; buffer < num_buffers; ++buffer) {
163 /* Allocate videobuf buffer structures */
164 vb = kzalloc(q->buf_struct_size, GFP_KERNEL);
166 dprintk(1, "Memory alloc for buffer struct failed\n");
170 /* Length stores number of planes for multiplanar buffers */
171 if (V4L2_TYPE_IS_MULTIPLANAR(q->type))
172 vb->v4l2_buf.length = num_planes;
174 vb->state = VB2_BUF_STATE_DEQUEUED;
176 vb->num_planes = num_planes;
177 vb->v4l2_buf.index = q->num_buffers + buffer;
178 vb->v4l2_buf.type = q->type;
179 vb->v4l2_buf.memory = memory;
181 /* Allocate video buffer memory for the MMAP type */
182 if (memory == V4L2_MEMORY_MMAP) {
183 ret = __vb2_buf_mem_alloc(vb);
185 dprintk(1, "Failed allocating memory for "
186 "buffer %d\n", buffer);
191 * Call the driver-provided buffer initialization
192 * callback, if given. An error in initialization
193 * results in queue setup failure.
195 ret = call_qop(q, buf_init, vb);
197 dprintk(1, "Buffer %d %p initialization"
198 " failed\n", buffer, vb);
199 __vb2_buf_mem_free(vb);
205 q->bufs[q->num_buffers + buffer] = vb;
208 __setup_offsets(q, buffer);
210 dprintk(1, "Allocated %d buffers, %d plane(s) each\n",
217 * __vb2_free_mem() - release all video buffer memory for a given queue
219 static void __vb2_free_mem(struct vb2_queue *q, unsigned int buffers)
222 struct vb2_buffer *vb;
224 for (buffer = q->num_buffers - buffers; buffer < q->num_buffers;
226 vb = q->bufs[buffer];
230 /* Free MMAP buffers or release USERPTR buffers */
231 if (q->memory == V4L2_MEMORY_MMAP)
232 __vb2_buf_mem_free(vb);
234 __vb2_buf_userptr_put(vb);
239 * __vb2_queue_free() - free buffers at the end of the queue - video memory and
240 * related information, if no buffers are left return the queue to an
241 * uninitialized state. Might be called even if the queue has already been freed.
243 static void __vb2_queue_free(struct vb2_queue *q, unsigned int buffers)
247 /* Call driver-provided cleanup function for each buffer, if provided */
248 if (q->ops->buf_cleanup) {
249 for (buffer = q->num_buffers - buffers; buffer < q->num_buffers;
251 if (NULL == q->bufs[buffer])
253 q->ops->buf_cleanup(q->bufs[buffer]);
257 /* Release video buffer memory */
258 __vb2_free_mem(q, buffers);
260 /* Free videobuf buffers */
261 for (buffer = q->num_buffers - buffers; buffer < q->num_buffers;
263 kfree(q->bufs[buffer]);
264 q->bufs[buffer] = NULL;
267 q->num_buffers -= buffers;
270 INIT_LIST_HEAD(&q->queued_list);
274 * __verify_planes_array() - verify that the planes array passed in struct
275 * v4l2_buffer from userspace can be safely used
277 static int __verify_planes_array(struct vb2_buffer *vb, const struct v4l2_buffer *b)
279 /* Is memory for copying plane information present? */
280 if (NULL == b->m.planes) {
281 dprintk(1, "Multi-planar buffer passed but "
282 "planes array not provided\n");
286 if (b->length < vb->num_planes || b->length > VIDEO_MAX_PLANES) {
287 dprintk(1, "Incorrect planes array length, "
288 "expected %d, got %d\n", vb->num_planes, b->length);
296 * __buffer_in_use() - return true if the buffer is in use and
297 * the queue cannot be freed (by the means of REQBUFS(0)) call
299 static bool __buffer_in_use(struct vb2_queue *q, struct vb2_buffer *vb)
302 for (plane = 0; plane < vb->num_planes; ++plane) {
303 void *mem_priv = vb->planes[plane].mem_priv;
305 * If num_users() has not been provided, call_memop
306 * will return 0, apparently nobody cares about this
307 * case anyway. If num_users() returns more than 1,
308 * we are not the only user of the plane's memory.
310 if (mem_priv && call_memop(q, num_users, mem_priv) > 1)
317 * __buffers_in_use() - return true if any buffers on the queue are in use and
318 * the queue cannot be freed (by the means of REQBUFS(0)) call
320 static bool __buffers_in_use(struct vb2_queue *q)
323 for (buffer = 0; buffer < q->num_buffers; ++buffer) {
324 if (__buffer_in_use(q, q->bufs[buffer]))
331 * __fill_v4l2_buffer() - fill in a struct v4l2_buffer with information to be
332 * returned to userspace
334 static int __fill_v4l2_buffer(struct vb2_buffer *vb, struct v4l2_buffer *b)
336 struct vb2_queue *q = vb->vb2_queue;
339 /* Copy back data such as timestamp, flags, input, etc. */
340 memcpy(b, &vb->v4l2_buf, offsetof(struct v4l2_buffer, m));
341 b->input = vb->v4l2_buf.input;
342 b->reserved = vb->v4l2_buf.reserved;
344 if (V4L2_TYPE_IS_MULTIPLANAR(q->type)) {
345 ret = __verify_planes_array(vb, b);
350 * Fill in plane-related data if userspace provided an array
351 * for it. The memory and size is verified above.
353 memcpy(b->m.planes, vb->v4l2_planes,
354 b->length * sizeof(struct v4l2_plane));
357 * We use length and offset in v4l2_planes array even for
358 * single-planar buffers, but userspace does not.
360 b->length = vb->v4l2_planes[0].length;
361 b->bytesused = vb->v4l2_planes[0].bytesused;
362 if (q->memory == V4L2_MEMORY_MMAP)
363 b->m.offset = vb->v4l2_planes[0].m.mem_offset;
364 else if (q->memory == V4L2_MEMORY_USERPTR)
365 b->m.userptr = vb->v4l2_planes[0].m.userptr;
369 * Clear any buffer state related flags.
371 b->flags &= ~V4L2_BUFFER_STATE_FLAGS;
374 case VB2_BUF_STATE_QUEUED:
375 case VB2_BUF_STATE_ACTIVE:
376 b->flags |= V4L2_BUF_FLAG_QUEUED;
378 case VB2_BUF_STATE_ERROR:
379 b->flags |= V4L2_BUF_FLAG_ERROR;
381 case VB2_BUF_STATE_DONE:
382 b->flags |= V4L2_BUF_FLAG_DONE;
384 case VB2_BUF_STATE_PREPARED:
385 b->flags |= V4L2_BUF_FLAG_PREPARED;
387 case VB2_BUF_STATE_DEQUEUED:
392 if (__buffer_in_use(q, vb))
393 b->flags |= V4L2_BUF_FLAG_MAPPED;
399 * vb2_querybuf() - query video buffer information
401 * @b: buffer struct passed from userspace to vidioc_querybuf handler
404 * Should be called from vidioc_querybuf ioctl handler in driver.
405 * This function will verify the passed v4l2_buffer structure and fill the
406 * relevant information for the userspace.
408 * The return values from this function are intended to be directly returned
409 * from vidioc_querybuf handler in driver.
411 int vb2_querybuf(struct vb2_queue *q, struct v4l2_buffer *b)
413 struct vb2_buffer *vb;
415 if (b->type != q->type) {
416 dprintk(1, "querybuf: wrong buffer type\n");
420 if (b->index >= q->num_buffers) {
421 dprintk(1, "querybuf: buffer index out of range\n");
424 vb = q->bufs[b->index];
426 return __fill_v4l2_buffer(vb, b);
428 EXPORT_SYMBOL(vb2_querybuf);
431 * __verify_userptr_ops() - verify that all memory operations required for
432 * USERPTR queue type have been provided
434 static int __verify_userptr_ops(struct vb2_queue *q)
436 if (!(q->io_modes & VB2_USERPTR) || !q->mem_ops->get_userptr ||
437 !q->mem_ops->put_userptr)
444 * __verify_mmap_ops() - verify that all memory operations required for
445 * MMAP queue type have been provided
447 static int __verify_mmap_ops(struct vb2_queue *q)
449 if (!(q->io_modes & VB2_MMAP) || !q->mem_ops->alloc ||
450 !q->mem_ops->put || !q->mem_ops->mmap)
457 * vb2_reqbufs() - Initiate streaming
458 * @q: videobuf2 queue
459 * @req: struct passed from userspace to vidioc_reqbufs handler in driver
461 * Should be called from vidioc_reqbufs ioctl handler of a driver.
463 * 1) verifies streaming parameters passed from the userspace,
464 * 2) sets up the queue,
465 * 3) negotiates number of buffers and planes per buffer with the driver
466 * to be used during streaming,
467 * 4) allocates internal buffer structures (struct vb2_buffer), according to
468 * the agreed parameters,
469 * 5) for MMAP memory type, allocates actual video memory, using the
470 * memory handling/allocation routines provided during queue initialization
472 * If req->count is 0, all the memory will be freed instead.
473 * If the queue has been allocated previously (by a previous vb2_reqbufs) call
474 * and the queue is not busy, memory will be reallocated.
476 * The return values from this function are intended to be directly returned
477 * from vidioc_reqbufs handler in driver.
479 int vb2_reqbufs(struct vb2_queue *q, struct v4l2_requestbuffers *req)
481 unsigned int num_buffers, allocated_buffers, num_planes = 0;
485 dprintk(1, "reqbufs: file io in progress\n");
489 if (req->memory != V4L2_MEMORY_MMAP
490 && req->memory != V4L2_MEMORY_USERPTR) {
491 dprintk(1, "reqbufs: unsupported memory type\n");
495 if (req->type != q->type) {
496 dprintk(1, "reqbufs: requested type is incorrect\n");
501 dprintk(1, "reqbufs: streaming active\n");
506 * Make sure all the required memory ops for given memory type
509 if (req->memory == V4L2_MEMORY_MMAP && __verify_mmap_ops(q)) {
510 dprintk(1, "reqbufs: MMAP for current setup unsupported\n");
514 if (req->memory == V4L2_MEMORY_USERPTR && __verify_userptr_ops(q)) {
515 dprintk(1, "reqbufs: USERPTR for current setup unsupported\n");
519 if (req->count == 0 || q->num_buffers != 0 || q->memory != req->memory) {
521 * We already have buffers allocated, so first check if they
522 * are not in use and can be freed.
524 if (q->memory == V4L2_MEMORY_MMAP && __buffers_in_use(q)) {
525 dprintk(1, "reqbufs: memory in use, cannot free\n");
529 __vb2_queue_free(q, q->num_buffers);
532 * In case of REQBUFS(0) return immediately without calling
533 * driver's queue_setup() callback and allocating resources.
540 * Make sure the requested values and current defaults are sane.
542 num_buffers = min_t(unsigned int, req->count, VIDEO_MAX_FRAME);
543 memset(q->plane_sizes, 0, sizeof(q->plane_sizes));
544 memset(q->alloc_ctx, 0, sizeof(q->alloc_ctx));
545 q->memory = req->memory;
548 * Ask the driver how many buffers and planes per buffer it requires.
549 * Driver also sets the size and allocator context for each plane.
551 ret = call_qop(q, queue_setup, q, NULL, &num_buffers, &num_planes,
552 q->plane_sizes, q->alloc_ctx);
556 /* Finally, allocate buffers and video memory */
557 ret = __vb2_queue_alloc(q, req->memory, num_buffers, num_planes);
559 dprintk(1, "Memory allocation failed\n");
563 allocated_buffers = ret;
566 * Check if driver can handle the allocated number of buffers.
568 if (allocated_buffers < num_buffers) {
569 num_buffers = allocated_buffers;
571 ret = call_qop(q, queue_setup, q, NULL, &num_buffers,
572 &num_planes, q->plane_sizes, q->alloc_ctx);
574 if (!ret && allocated_buffers < num_buffers)
578 * Either the driver has accepted a smaller number of buffers,
579 * or .queue_setup() returned an error
583 q->num_buffers = allocated_buffers;
586 __vb2_queue_free(q, allocated_buffers);
591 * Return the number of successfully allocated buffers
594 req->count = allocated_buffers;
598 EXPORT_SYMBOL_GPL(vb2_reqbufs);
601 * vb2_create_bufs() - Allocate buffers and any required auxiliary structs
602 * @q: videobuf2 queue
603 * @create: creation parameters, passed from userspace to vidioc_create_bufs
606 * Should be called from vidioc_create_bufs ioctl handler of a driver.
608 * 1) verifies parameter sanity
609 * 2) calls the .queue_setup() queue operation
610 * 3) performs any necessary memory allocations
612 * The return values from this function are intended to be directly returned
613 * from vidioc_create_bufs handler in driver.
615 int vb2_create_bufs(struct vb2_queue *q, struct v4l2_create_buffers *create)
617 unsigned int num_planes = 0, num_buffers, allocated_buffers;
621 dprintk(1, "%s(): file io in progress\n", __func__);
625 if (create->memory != V4L2_MEMORY_MMAP
626 && create->memory != V4L2_MEMORY_USERPTR) {
627 dprintk(1, "%s(): unsupported memory type\n", __func__);
631 if (create->format.type != q->type) {
632 dprintk(1, "%s(): requested type is incorrect\n", __func__);
637 * Make sure all the required memory ops for given memory type
640 if (create->memory == V4L2_MEMORY_MMAP && __verify_mmap_ops(q)) {
641 dprintk(1, "%s(): MMAP for current setup unsupported\n", __func__);
645 if (create->memory == V4L2_MEMORY_USERPTR && __verify_userptr_ops(q)) {
646 dprintk(1, "%s(): USERPTR for current setup unsupported\n", __func__);
650 if (q->num_buffers == VIDEO_MAX_FRAME) {
651 dprintk(1, "%s(): maximum number of buffers already allocated\n",
656 create->index = q->num_buffers;
658 if (!q->num_buffers) {
659 memset(q->plane_sizes, 0, sizeof(q->plane_sizes));
660 memset(q->alloc_ctx, 0, sizeof(q->alloc_ctx));
661 q->memory = create->memory;
664 num_buffers = min(create->count, VIDEO_MAX_FRAME - q->num_buffers);
667 * Ask the driver, whether the requested number of buffers, planes per
668 * buffer and their sizes are acceptable
670 ret = call_qop(q, queue_setup, q, &create->format, &num_buffers,
671 &num_planes, q->plane_sizes, q->alloc_ctx);
675 /* Finally, allocate buffers and video memory */
676 ret = __vb2_queue_alloc(q, create->memory, num_buffers,
679 dprintk(1, "Memory allocation failed with error: %d\n", ret);
683 allocated_buffers = ret;
686 * Check if driver can handle the so far allocated number of buffers.
688 if (ret < num_buffers) {
692 * q->num_buffers contains the total number of buffers, that the
693 * queue driver has set up
695 ret = call_qop(q, queue_setup, q, &create->format, &num_buffers,
696 &num_planes, q->plane_sizes, q->alloc_ctx);
698 if (!ret && allocated_buffers < num_buffers)
702 * Either the driver has accepted a smaller number of buffers,
703 * or .queue_setup() returned an error
707 q->num_buffers += allocated_buffers;
710 __vb2_queue_free(q, allocated_buffers);
715 * Return the number of successfully allocated buffers
718 create->count = allocated_buffers;
722 EXPORT_SYMBOL_GPL(vb2_create_bufs);
725 * vb2_plane_vaddr() - Return a kernel virtual address of a given plane
726 * @vb: vb2_buffer to which the plane in question belongs to
727 * @plane_no: plane number for which the address is to be returned
729 * This function returns a kernel virtual address of a given plane if
730 * such a mapping exist, NULL otherwise.
732 void *vb2_plane_vaddr(struct vb2_buffer *vb, unsigned int plane_no)
734 struct vb2_queue *q = vb->vb2_queue;
736 if (plane_no > vb->num_planes || !vb->planes[plane_no].mem_priv)
739 return call_memop(q, vaddr, vb->planes[plane_no].mem_priv);
742 EXPORT_SYMBOL_GPL(vb2_plane_vaddr);
745 * vb2_plane_cookie() - Return allocator specific cookie for the given plane
746 * @vb: vb2_buffer to which the plane in question belongs to
747 * @plane_no: plane number for which the cookie is to be returned
749 * This function returns an allocator specific cookie for a given plane if
750 * available, NULL otherwise. The allocator should provide some simple static
751 * inline function, which would convert this cookie to the allocator specific
752 * type that can be used directly by the driver to access the buffer. This can
753 * be for example physical address, pointer to scatter list or IOMMU mapping.
755 void *vb2_plane_cookie(struct vb2_buffer *vb, unsigned int plane_no)
757 struct vb2_queue *q = vb->vb2_queue;
759 if (plane_no > vb->num_planes || !vb->planes[plane_no].mem_priv)
762 return call_memop(q, cookie, vb->planes[plane_no].mem_priv);
764 EXPORT_SYMBOL_GPL(vb2_plane_cookie);
767 * vb2_buffer_done() - inform videobuf that an operation on a buffer is finished
768 * @vb: vb2_buffer returned from the driver
769 * @state: either VB2_BUF_STATE_DONE if the operation finished successfully
770 * or VB2_BUF_STATE_ERROR if the operation finished with an error
772 * This function should be called by the driver after a hardware operation on
773 * a buffer is finished and the buffer may be returned to userspace. The driver
774 * cannot use this buffer anymore until it is queued back to it by videobuf
775 * by the means of buf_queue callback. Only buffers previously queued to the
776 * driver by buf_queue can be passed to this function.
778 void vb2_buffer_done(struct vb2_buffer *vb, enum vb2_buffer_state state)
780 struct vb2_queue *q = vb->vb2_queue;
783 if (vb->state != VB2_BUF_STATE_ACTIVE)
786 if (state != VB2_BUF_STATE_DONE && state != VB2_BUF_STATE_ERROR)
789 dprintk(4, "Done processing on buffer %d, state: %d\n",
790 vb->v4l2_buf.index, vb->state);
792 /* Add the buffer to the done buffers list */
793 spin_lock_irqsave(&q->done_lock, flags);
795 list_add_tail(&vb->done_entry, &q->done_list);
796 atomic_dec(&q->queued_count);
797 spin_unlock_irqrestore(&q->done_lock, flags);
799 /* Inform any processes that may be waiting for buffers */
800 wake_up(&q->done_wq);
802 EXPORT_SYMBOL_GPL(vb2_buffer_done);
805 * __fill_vb2_buffer() - fill a vb2_buffer with information provided in
806 * a v4l2_buffer by the userspace
808 static int __fill_vb2_buffer(struct vb2_buffer *vb, const struct v4l2_buffer *b,
809 struct v4l2_plane *v4l2_planes)
814 if (V4L2_TYPE_IS_MULTIPLANAR(b->type)) {
816 * Verify that the userspace gave us a valid array for
819 ret = __verify_planes_array(vb, b);
823 /* Fill in driver-provided information for OUTPUT types */
824 if (V4L2_TYPE_IS_OUTPUT(b->type)) {
826 * Will have to go up to b->length when API starts
827 * accepting variable number of planes.
829 for (plane = 0; plane < vb->num_planes; ++plane) {
830 v4l2_planes[plane].bytesused =
831 b->m.planes[plane].bytesused;
832 v4l2_planes[plane].data_offset =
833 b->m.planes[plane].data_offset;
837 if (b->memory == V4L2_MEMORY_USERPTR) {
838 for (plane = 0; plane < vb->num_planes; ++plane) {
839 v4l2_planes[plane].m.userptr =
840 b->m.planes[plane].m.userptr;
841 v4l2_planes[plane].length =
842 b->m.planes[plane].length;
847 * Single-planar buffers do not use planes array,
848 * so fill in relevant v4l2_buffer struct fields instead.
849 * In videobuf we use our internal V4l2_planes struct for
850 * single-planar buffers as well, for simplicity.
852 if (V4L2_TYPE_IS_OUTPUT(b->type))
853 v4l2_planes[0].bytesused = b->bytesused;
855 if (b->memory == V4L2_MEMORY_USERPTR) {
856 v4l2_planes[0].m.userptr = b->m.userptr;
857 v4l2_planes[0].length = b->length;
861 vb->v4l2_buf.field = b->field;
862 vb->v4l2_buf.timestamp = b->timestamp;
863 vb->v4l2_buf.input = b->input;
864 vb->v4l2_buf.flags = b->flags & ~V4L2_BUFFER_STATE_FLAGS;
870 * __qbuf_userptr() - handle qbuf of a USERPTR buffer
872 static int __qbuf_userptr(struct vb2_buffer *vb, const struct v4l2_buffer *b)
874 struct v4l2_plane planes[VIDEO_MAX_PLANES];
875 struct vb2_queue *q = vb->vb2_queue;
879 int write = !V4L2_TYPE_IS_OUTPUT(q->type);
881 /* Verify and copy relevant information provided by the userspace */
882 ret = __fill_vb2_buffer(vb, b, planes);
886 for (plane = 0; plane < vb->num_planes; ++plane) {
887 /* Skip the plane if already verified */
888 if (vb->v4l2_planes[plane].m.userptr &&
889 vb->v4l2_planes[plane].m.userptr == planes[plane].m.userptr
890 && vb->v4l2_planes[plane].length == planes[plane].length)
893 dprintk(3, "qbuf: userspace address for plane %d changed, "
894 "reacquiring memory\n", plane);
896 /* Check if the provided plane buffer is large enough */
897 if (planes[plane].length < q->plane_sizes[plane]) {
902 /* Release previously acquired memory if present */
903 if (vb->planes[plane].mem_priv)
904 call_memop(q, put_userptr, vb->planes[plane].mem_priv);
906 vb->planes[plane].mem_priv = NULL;
907 vb->v4l2_planes[plane].m.userptr = 0;
908 vb->v4l2_planes[plane].length = 0;
910 /* Acquire each plane's memory */
911 mem_priv = call_memop(q, get_userptr, q->alloc_ctx[plane],
912 planes[plane].m.userptr,
913 planes[plane].length, write);
914 if (IS_ERR_OR_NULL(mem_priv)) {
915 dprintk(1, "qbuf: failed acquiring userspace "
916 "memory for plane %d\n", plane);
917 ret = mem_priv ? PTR_ERR(mem_priv) : -EINVAL;
920 vb->planes[plane].mem_priv = mem_priv;
924 * Call driver-specific initialization on the newly acquired buffer,
927 ret = call_qop(q, buf_init, vb);
929 dprintk(1, "qbuf: buffer initialization failed\n");
934 * Now that everything is in order, copy relevant information
935 * provided by userspace.
937 for (plane = 0; plane < vb->num_planes; ++plane)
938 vb->v4l2_planes[plane] = planes[plane];
942 /* In case of errors, release planes that were already acquired */
943 for (plane = 0; plane < vb->num_planes; ++plane) {
944 if (vb->planes[plane].mem_priv)
945 call_memop(q, put_userptr, vb->planes[plane].mem_priv);
946 vb->planes[plane].mem_priv = NULL;
947 vb->v4l2_planes[plane].m.userptr = 0;
948 vb->v4l2_planes[plane].length = 0;
955 * __qbuf_mmap() - handle qbuf of an MMAP buffer
957 static int __qbuf_mmap(struct vb2_buffer *vb, const struct v4l2_buffer *b)
959 return __fill_vb2_buffer(vb, b, vb->v4l2_planes);
963 * __enqueue_in_driver() - enqueue a vb2_buffer in driver for processing
965 static void __enqueue_in_driver(struct vb2_buffer *vb)
967 struct vb2_queue *q = vb->vb2_queue;
969 vb->state = VB2_BUF_STATE_ACTIVE;
970 atomic_inc(&q->queued_count);
971 q->ops->buf_queue(vb);
974 static int __buf_prepare(struct vb2_buffer *vb, const struct v4l2_buffer *b)
976 struct vb2_queue *q = vb->vb2_queue;
980 case V4L2_MEMORY_MMAP:
981 ret = __qbuf_mmap(vb, b);
983 case V4L2_MEMORY_USERPTR:
984 ret = __qbuf_userptr(vb, b);
987 WARN(1, "Invalid queue type\n");
992 ret = call_qop(q, buf_prepare, vb);
994 dprintk(1, "qbuf: buffer preparation failed: %d\n", ret);
996 vb->state = VB2_BUF_STATE_PREPARED;
1002 * vb2_prepare_buf() - Pass ownership of a buffer from userspace to the kernel
1003 * @q: videobuf2 queue
1004 * @b: buffer structure passed from userspace to vidioc_prepare_buf
1007 * Should be called from vidioc_prepare_buf ioctl handler of a driver.
1009 * 1) verifies the passed buffer,
1010 * 2) calls buf_prepare callback in the driver (if provided), in which
1011 * driver-specific buffer initialization can be performed,
1013 * The return values from this function are intended to be directly returned
1014 * from vidioc_prepare_buf handler in driver.
1016 int vb2_prepare_buf(struct vb2_queue *q, struct v4l2_buffer *b)
1018 struct vb2_buffer *vb;
1022 dprintk(1, "%s(): file io in progress\n", __func__);
1026 if (b->type != q->type) {
1027 dprintk(1, "%s(): invalid buffer type\n", __func__);
1031 if (b->index >= q->num_buffers) {
1032 dprintk(1, "%s(): buffer index out of range\n", __func__);
1036 vb = q->bufs[b->index];
1038 /* Should never happen */
1039 dprintk(1, "%s(): buffer is NULL\n", __func__);
1043 if (b->memory != q->memory) {
1044 dprintk(1, "%s(): invalid memory type\n", __func__);
1048 if (vb->state != VB2_BUF_STATE_DEQUEUED) {
1049 dprintk(1, "%s(): invalid buffer state %d\n", __func__, vb->state);
1053 ret = __buf_prepare(vb, b);
1057 __fill_v4l2_buffer(vb, b);
1061 EXPORT_SYMBOL_GPL(vb2_prepare_buf);
1064 * vb2_qbuf() - Queue a buffer from userspace
1065 * @q: videobuf2 queue
1066 * @b: buffer structure passed from userspace to vidioc_qbuf handler
1069 * Should be called from vidioc_qbuf ioctl handler of a driver.
1071 * 1) verifies the passed buffer,
1072 * 2) if necessary, calls buf_prepare callback in the driver (if provided), in
1073 * which driver-specific buffer initialization can be performed,
1074 * 3) if streaming is on, queues the buffer in driver by the means of buf_queue
1075 * callback for processing.
1077 * The return values from this function are intended to be directly returned
1078 * from vidioc_qbuf handler in driver.
1080 int vb2_qbuf(struct vb2_queue *q, struct v4l2_buffer *b)
1082 struct rw_semaphore *mmap_sem = NULL;
1083 struct vb2_buffer *vb;
1087 * In case of user pointer buffers vb2 allocator needs to get direct
1088 * access to userspace pages. This requires getting read access on
1089 * mmap semaphore in the current process structure. The same
1090 * semaphore is taken before calling mmap operation, while both mmap
1091 * and qbuf are called by the driver or v4l2 core with driver's lock
1092 * held. To avoid a AB-BA deadlock (mmap_sem then driver's lock in
1093 * mmap and driver's lock then mmap_sem in qbuf) the videobuf2 core
1094 * release driver's lock, takes mmap_sem and then takes again driver's
1097 * To avoid race with other vb2 calls, which might be called after
1098 * releasing driver's lock, this operation is performed at the
1099 * beggining of qbuf processing. This way the queue status is
1100 * consistent after getting driver's lock back.
1102 if (q->memory == V4L2_MEMORY_USERPTR) {
1103 mmap_sem = ¤t->mm->mmap_sem;
1104 call_qop(q, wait_prepare, q);
1105 down_read(mmap_sem);
1106 call_qop(q, wait_finish, q);
1110 dprintk(1, "qbuf: file io in progress\n");
1115 if (b->type != q->type) {
1116 dprintk(1, "qbuf: invalid buffer type\n");
1121 if (b->index >= q->num_buffers) {
1122 dprintk(1, "qbuf: buffer index out of range\n");
1127 vb = q->bufs[b->index];
1129 /* Should never happen */
1130 dprintk(1, "qbuf: buffer is NULL\n");
1135 if (b->memory != q->memory) {
1136 dprintk(1, "qbuf: invalid memory type\n");
1141 switch (vb->state) {
1142 case VB2_BUF_STATE_DEQUEUED:
1143 ret = __buf_prepare(vb, b);
1146 case VB2_BUF_STATE_PREPARED:
1149 dprintk(1, "qbuf: buffer already in use\n");
1155 * Add to the queued buffers list, a buffer will stay on it until
1156 * dequeued in dqbuf.
1158 list_add_tail(&vb->queued_entry, &q->queued_list);
1159 vb->state = VB2_BUF_STATE_QUEUED;
1162 * If already streaming, give the buffer to driver for processing.
1163 * If not, the buffer will be given to driver on next streamon.
1166 __enqueue_in_driver(vb);
1168 /* Fill buffer information for the userspace */
1169 __fill_v4l2_buffer(vb, b);
1171 dprintk(1, "qbuf of buffer %d succeeded\n", vb->v4l2_buf.index);
1177 EXPORT_SYMBOL_GPL(vb2_qbuf);
1180 * __vb2_wait_for_done_vb() - wait for a buffer to become available
1183 * Will sleep if required for nonblocking == false.
1185 static int __vb2_wait_for_done_vb(struct vb2_queue *q, int nonblocking)
1188 * All operations on vb_done_list are performed under done_lock
1189 * spinlock protection. However, buffers may be removed from
1190 * it and returned to userspace only while holding both driver's
1191 * lock and the done_lock spinlock. Thus we can be sure that as
1192 * long as we hold the driver's lock, the list will remain not
1193 * empty if list_empty() check succeeds.
1199 if (!q->streaming) {
1200 dprintk(1, "Streaming off, will not wait for buffers\n");
1204 if (!list_empty(&q->done_list)) {
1206 * Found a buffer that we were waiting for.
1212 dprintk(1, "Nonblocking and no buffers to dequeue, "
1218 * We are streaming and blocking, wait for another buffer to
1219 * become ready or for streamoff. Driver's lock is released to
1220 * allow streamoff or qbuf to be called while waiting.
1222 call_qop(q, wait_prepare, q);
1225 * All locks have been released, it is safe to sleep now.
1227 dprintk(3, "Will sleep waiting for buffers\n");
1228 ret = wait_event_interruptible(q->done_wq,
1229 !list_empty(&q->done_list) || !q->streaming);
1232 * We need to reevaluate both conditions again after reacquiring
1233 * the locks or return an error if one occurred.
1235 call_qop(q, wait_finish, q);
1243 * __vb2_get_done_vb() - get a buffer ready for dequeuing
1245 * Will sleep if required for nonblocking == false.
1247 static int __vb2_get_done_vb(struct vb2_queue *q, struct vb2_buffer **vb,
1250 unsigned long flags;
1254 * Wait for at least one buffer to become available on the done_list.
1256 ret = __vb2_wait_for_done_vb(q, nonblocking);
1261 * Driver's lock has been held since we last verified that done_list
1262 * is not empty, so no need for another list_empty(done_list) check.
1264 spin_lock_irqsave(&q->done_lock, flags);
1265 *vb = list_first_entry(&q->done_list, struct vb2_buffer, done_entry);
1266 list_del(&(*vb)->done_entry);
1267 spin_unlock_irqrestore(&q->done_lock, flags);
1273 * vb2_wait_for_all_buffers() - wait until all buffers are given back to vb2
1274 * @q: videobuf2 queue
1276 * This function will wait until all buffers that have been given to the driver
1277 * by buf_queue() are given back to vb2 with vb2_buffer_done(). It doesn't call
1278 * wait_prepare, wait_finish pair. It is intended to be called with all locks
1279 * taken, for example from stop_streaming() callback.
1281 int vb2_wait_for_all_buffers(struct vb2_queue *q)
1283 if (!q->streaming) {
1284 dprintk(1, "Streaming off, will not wait for buffers\n");
1288 wait_event(q->done_wq, !atomic_read(&q->queued_count));
1291 EXPORT_SYMBOL_GPL(vb2_wait_for_all_buffers);
1294 * vb2_dqbuf() - Dequeue a buffer to the userspace
1295 * @q: videobuf2 queue
1296 * @b: buffer structure passed from userspace to vidioc_dqbuf handler
1298 * @nonblocking: if true, this call will not sleep waiting for a buffer if no
1299 * buffers ready for dequeuing are present. Normally the driver
1300 * would be passing (file->f_flags & O_NONBLOCK) here
1302 * Should be called from vidioc_dqbuf ioctl handler of a driver.
1304 * 1) verifies the passed buffer,
1305 * 2) calls buf_finish callback in the driver (if provided), in which
1306 * driver can perform any additional operations that may be required before
1307 * returning the buffer to userspace, such as cache sync,
1308 * 3) the buffer struct members are filled with relevant information for
1311 * The return values from this function are intended to be directly returned
1312 * from vidioc_dqbuf handler in driver.
1314 int vb2_dqbuf(struct vb2_queue *q, struct v4l2_buffer *b, bool nonblocking)
1316 struct vb2_buffer *vb = NULL;
1320 dprintk(1, "dqbuf: file io in progress\n");
1324 if (b->type != q->type) {
1325 dprintk(1, "dqbuf: invalid buffer type\n");
1329 ret = __vb2_get_done_vb(q, &vb, nonblocking);
1331 dprintk(1, "dqbuf: error getting next done buffer\n");
1335 ret = call_qop(q, buf_finish, vb);
1337 dprintk(1, "dqbuf: buffer finish failed\n");
1341 switch (vb->state) {
1342 case VB2_BUF_STATE_DONE:
1343 dprintk(3, "dqbuf: Returning done buffer\n");
1345 case VB2_BUF_STATE_ERROR:
1346 dprintk(3, "dqbuf: Returning done buffer with errors\n");
1349 dprintk(1, "dqbuf: Invalid buffer state\n");
1353 /* Fill buffer information for the userspace */
1354 __fill_v4l2_buffer(vb, b);
1355 /* Remove from videobuf queue */
1356 list_del(&vb->queued_entry);
1358 dprintk(1, "dqbuf of buffer %d, with state %d\n",
1359 vb->v4l2_buf.index, vb->state);
1361 vb->state = VB2_BUF_STATE_DEQUEUED;
1364 EXPORT_SYMBOL_GPL(vb2_dqbuf);
1367 * __vb2_queue_cancel() - cancel and stop (pause) streaming
1369 * Removes all queued buffers from driver's queue and all buffers queued by
1370 * userspace from videobuf's queue. Returns to state after reqbufs.
1372 static void __vb2_queue_cancel(struct vb2_queue *q)
1377 * Tell driver to stop all transactions and release all queued
1381 call_qop(q, stop_streaming, q);
1385 * Remove all buffers from videobuf's list...
1387 INIT_LIST_HEAD(&q->queued_list);
1389 * ...and done list; userspace will not receive any buffers it
1390 * has not already dequeued before initiating cancel.
1392 INIT_LIST_HEAD(&q->done_list);
1393 atomic_set(&q->queued_count, 0);
1394 wake_up_all(&q->done_wq);
1397 * Reinitialize all buffers for next use.
1399 for (i = 0; i < q->num_buffers; ++i)
1400 q->bufs[i]->state = VB2_BUF_STATE_DEQUEUED;
1404 * vb2_streamon - start streaming
1405 * @q: videobuf2 queue
1406 * @type: type argument passed from userspace to vidioc_streamon handler
1408 * Should be called from vidioc_streamon handler of a driver.
1410 * 1) verifies current state
1411 * 2) passes any previously queued buffers to the driver and starts streaming
1413 * The return values from this function are intended to be directly returned
1414 * from vidioc_streamon handler in the driver.
1416 int vb2_streamon(struct vb2_queue *q, enum v4l2_buf_type type)
1418 struct vb2_buffer *vb;
1422 dprintk(1, "streamon: file io in progress\n");
1426 if (type != q->type) {
1427 dprintk(1, "streamon: invalid stream type\n");
1432 dprintk(1, "streamon: already streaming\n");
1437 * If any buffers were queued before streamon,
1438 * we can now pass them to driver for processing.
1440 list_for_each_entry(vb, &q->queued_list, queued_entry)
1441 __enqueue_in_driver(vb);
1444 * Let driver notice that streaming state has been enabled.
1446 ret = call_qop(q, start_streaming, q, atomic_read(&q->queued_count));
1448 dprintk(1, "streamon: driver refused to start streaming\n");
1449 __vb2_queue_cancel(q);
1455 dprintk(3, "Streamon successful\n");
1458 EXPORT_SYMBOL_GPL(vb2_streamon);
1462 * vb2_streamoff - stop streaming
1463 * @q: videobuf2 queue
1464 * @type: type argument passed from userspace to vidioc_streamoff handler
1466 * Should be called from vidioc_streamoff handler of a driver.
1468 * 1) verifies current state,
1469 * 2) stop streaming and dequeues any queued buffers, including those previously
1470 * passed to the driver (after waiting for the driver to finish).
1472 * This call can be used for pausing playback.
1473 * The return values from this function are intended to be directly returned
1474 * from vidioc_streamoff handler in the driver
1476 int vb2_streamoff(struct vb2_queue *q, enum v4l2_buf_type type)
1479 dprintk(1, "streamoff: file io in progress\n");
1483 if (type != q->type) {
1484 dprintk(1, "streamoff: invalid stream type\n");
1488 if (!q->streaming) {
1489 dprintk(1, "streamoff: not streaming\n");
1494 * Cancel will pause streaming and remove all buffers from the driver
1495 * and videobuf, effectively returning control over them to userspace.
1497 __vb2_queue_cancel(q);
1499 dprintk(3, "Streamoff successful\n");
1502 EXPORT_SYMBOL_GPL(vb2_streamoff);
1505 * __find_plane_by_offset() - find plane associated with the given offset off
1507 static int __find_plane_by_offset(struct vb2_queue *q, unsigned long off,
1508 unsigned int *_buffer, unsigned int *_plane)
1510 struct vb2_buffer *vb;
1511 unsigned int buffer, plane;
1514 * Go over all buffers and their planes, comparing the given offset
1515 * with an offset assigned to each plane. If a match is found,
1516 * return its buffer and plane numbers.
1518 for (buffer = 0; buffer < q->num_buffers; ++buffer) {
1519 vb = q->bufs[buffer];
1521 for (plane = 0; plane < vb->num_planes; ++plane) {
1522 if (vb->v4l2_planes[plane].m.mem_offset == off) {
1534 * vb2_mmap() - map video buffers into application address space
1535 * @q: videobuf2 queue
1536 * @vma: vma passed to the mmap file operation handler in the driver
1538 * Should be called from mmap file operation handler of a driver.
1539 * This function maps one plane of one of the available video buffers to
1540 * userspace. To map whole video memory allocated on reqbufs, this function
1541 * has to be called once per each plane per each buffer previously allocated.
1543 * When the userspace application calls mmap, it passes to it an offset returned
1544 * to it earlier by the means of vidioc_querybuf handler. That offset acts as
1545 * a "cookie", which is then used to identify the plane to be mapped.
1546 * This function finds a plane with a matching offset and a mapping is performed
1547 * by the means of a provided memory operation.
1549 * The return values from this function are intended to be directly returned
1550 * from the mmap handler in driver.
1552 int vb2_mmap(struct vb2_queue *q, struct vm_area_struct *vma)
1554 unsigned long off = vma->vm_pgoff << PAGE_SHIFT;
1555 struct vb2_buffer *vb;
1556 unsigned int buffer, plane;
1559 if (q->memory != V4L2_MEMORY_MMAP) {
1560 dprintk(1, "Queue is not currently set up for mmap\n");
1565 * Check memory area access mode.
1567 if (!(vma->vm_flags & VM_SHARED)) {
1568 dprintk(1, "Invalid vma flags, VM_SHARED needed\n");
1571 if (V4L2_TYPE_IS_OUTPUT(q->type)) {
1572 if (!(vma->vm_flags & VM_WRITE)) {
1573 dprintk(1, "Invalid vma flags, VM_WRITE needed\n");
1577 if (!(vma->vm_flags & VM_READ)) {
1578 dprintk(1, "Invalid vma flags, VM_READ needed\n");
1584 * Find the plane corresponding to the offset passed by userspace.
1586 ret = __find_plane_by_offset(q, off, &buffer, &plane);
1590 vb = q->bufs[buffer];
1592 ret = call_memop(q, mmap, vb->planes[plane].mem_priv, vma);
1596 dprintk(3, "Buffer %d, plane %d successfully mapped\n", buffer, plane);
1599 EXPORT_SYMBOL_GPL(vb2_mmap);
1602 unsigned long vb2_get_unmapped_area(struct vb2_queue *q,
1605 unsigned long pgoff,
1606 unsigned long flags)
1608 unsigned long off = pgoff << PAGE_SHIFT;
1609 struct vb2_buffer *vb;
1610 unsigned int buffer, plane;
1613 if (q->memory != V4L2_MEMORY_MMAP) {
1614 dprintk(1, "Queue is not currently set up for mmap\n");
1619 * Find the plane corresponding to the offset passed by userspace.
1621 ret = __find_plane_by_offset(q, off, &buffer, &plane);
1625 vb = q->bufs[buffer];
1627 return (unsigned long)vb2_plane_vaddr(vb, plane);
1629 EXPORT_SYMBOL_GPL(vb2_get_unmapped_area);
1632 static int __vb2_init_fileio(struct vb2_queue *q, int read);
1633 static int __vb2_cleanup_fileio(struct vb2_queue *q);
1636 * vb2_poll() - implements poll userspace operation
1637 * @q: videobuf2 queue
1638 * @file: file argument passed to the poll file operation handler
1639 * @wait: wait argument passed to the poll file operation handler
1641 * This function implements poll file operation handler for a driver.
1642 * For CAPTURE queues, if a buffer is ready to be dequeued, the userspace will
1643 * be informed that the file descriptor of a video device is available for
1645 * For OUTPUT queues, if a buffer is ready to be dequeued, the file descriptor
1646 * will be reported as available for writing.
1648 * If the driver uses struct v4l2_fh, then vb2_poll() will also check for any
1651 * The return values from this function are intended to be directly returned
1652 * from poll handler in driver.
1654 unsigned int vb2_poll(struct vb2_queue *q, struct file *file, poll_table *wait)
1656 struct video_device *vfd = video_devdata(file);
1657 unsigned long req_events = poll_requested_events(wait);
1658 struct vb2_buffer *vb = NULL;
1659 unsigned int res = 0;
1660 unsigned long flags;
1662 if (test_bit(V4L2_FL_USES_V4L2_FH, &vfd->flags)) {
1663 struct v4l2_fh *fh = file->private_data;
1665 if (v4l2_event_pending(fh))
1667 else if (req_events & POLLPRI)
1668 poll_wait(file, &fh->wait, wait);
1672 * Start file I/O emulator only if streaming API has not been used yet.
1674 if (q->num_buffers == 0 && q->fileio == NULL) {
1675 if (!V4L2_TYPE_IS_OUTPUT(q->type) && (q->io_modes & VB2_READ) &&
1676 (req_events & (POLLIN | POLLRDNORM))) {
1677 if (__vb2_init_fileio(q, 1))
1678 return res | POLLERR;
1680 if (V4L2_TYPE_IS_OUTPUT(q->type) && (q->io_modes & VB2_WRITE) &&
1681 (req_events & (POLLOUT | POLLWRNORM))) {
1682 if (__vb2_init_fileio(q, 0))
1683 return res | POLLERR;
1685 * Write to OUTPUT queue can be done immediately.
1687 return res | POLLOUT | POLLWRNORM;
1692 * There is nothing to wait for if no buffers have already been queued.
1694 if (list_empty(&q->queued_list))
1695 return res | POLLERR;
1697 poll_wait(file, &q->done_wq, wait);
1700 * Take first buffer available for dequeuing.
1702 spin_lock_irqsave(&q->done_lock, flags);
1703 if (!list_empty(&q->done_list))
1704 vb = list_first_entry(&q->done_list, struct vb2_buffer,
1706 spin_unlock_irqrestore(&q->done_lock, flags);
1708 if (vb && (vb->state == VB2_BUF_STATE_DONE
1709 || vb->state == VB2_BUF_STATE_ERROR)) {
1710 return (V4L2_TYPE_IS_OUTPUT(q->type)) ?
1711 res | POLLOUT | POLLWRNORM :
1712 res | POLLIN | POLLRDNORM;
1716 EXPORT_SYMBOL_GPL(vb2_poll);
1719 * vb2_queue_init() - initialize a videobuf2 queue
1720 * @q: videobuf2 queue; this structure should be allocated in driver
1722 * The vb2_queue structure should be allocated by the driver. The driver is
1723 * responsible of clearing it's content and setting initial values for some
1724 * required entries before calling this function.
1725 * q->ops, q->mem_ops, q->type and q->io_modes are mandatory. Please refer
1726 * to the struct vb2_queue description in include/media/videobuf2-core.h
1727 * for more information.
1729 int vb2_queue_init(struct vb2_queue *q)
1733 BUG_ON(!q->mem_ops);
1735 BUG_ON(!q->io_modes);
1737 BUG_ON(!q->ops->queue_setup);
1738 BUG_ON(!q->ops->buf_queue);
1740 INIT_LIST_HEAD(&q->queued_list);
1741 INIT_LIST_HEAD(&q->done_list);
1742 spin_lock_init(&q->done_lock);
1743 init_waitqueue_head(&q->done_wq);
1745 if (q->buf_struct_size == 0)
1746 q->buf_struct_size = sizeof(struct vb2_buffer);
1750 EXPORT_SYMBOL_GPL(vb2_queue_init);
1753 * vb2_queue_release() - stop streaming, release the queue and free memory
1754 * @q: videobuf2 queue
1756 * This function stops streaming and performs necessary clean ups, including
1757 * freeing video buffer memory. The driver is responsible for freeing
1758 * the vb2_queue structure itself.
1760 void vb2_queue_release(struct vb2_queue *q)
1762 __vb2_cleanup_fileio(q);
1763 __vb2_queue_cancel(q);
1764 __vb2_queue_free(q, q->num_buffers);
1766 EXPORT_SYMBOL_GPL(vb2_queue_release);
1769 * struct vb2_fileio_buf - buffer context used by file io emulator
1771 * vb2 provides a compatibility layer and emulator of file io (read and
1772 * write) calls on top of streaming API. This structure is used for
1773 * tracking context related to the buffers.
1775 struct vb2_fileio_buf {
1779 unsigned int queued:1;
1783 * struct vb2_fileio_data - queue context used by file io emulator
1785 * vb2 provides a compatibility layer and emulator of file io (read and
1786 * write) calls on top of streaming API. For proper operation it required
1787 * this structure to save the driver state between each call of the read
1788 * or write function.
1790 struct vb2_fileio_data {
1791 struct v4l2_requestbuffers req;
1792 struct v4l2_buffer b;
1793 struct vb2_fileio_buf bufs[VIDEO_MAX_FRAME];
1795 unsigned int q_count;
1796 unsigned int dq_count;
1801 * __vb2_init_fileio() - initialize file io emulator
1802 * @q: videobuf2 queue
1803 * @read: mode selector (1 means read, 0 means write)
1805 static int __vb2_init_fileio(struct vb2_queue *q, int read)
1807 struct vb2_fileio_data *fileio;
1809 unsigned int count = 0;
1814 if ((read && !(q->io_modes & VB2_READ)) ||
1815 (!read && !(q->io_modes & VB2_WRITE)))
1819 * Check if device supports mapping buffers to kernel virtual space.
1821 if (!q->mem_ops->vaddr)
1825 * Check if streaming api has not been already activated.
1827 if (q->streaming || q->num_buffers > 0)
1831 * Start with count 1, driver can increase it in queue_setup()
1835 dprintk(3, "setting up file io: mode %s, count %d, flags %08x\n",
1836 (read) ? "read" : "write", count, q->io_flags);
1838 fileio = kzalloc(sizeof(struct vb2_fileio_data), GFP_KERNEL);
1842 fileio->flags = q->io_flags;
1845 * Request buffers and use MMAP type to force driver
1846 * to allocate buffers by itself.
1848 fileio->req.count = count;
1849 fileio->req.memory = V4L2_MEMORY_MMAP;
1850 fileio->req.type = q->type;
1851 ret = vb2_reqbufs(q, &fileio->req);
1856 * Check if plane_count is correct
1857 * (multiplane buffers are not supported).
1859 if (q->bufs[0]->num_planes != 1) {
1865 * Get kernel address of each buffer.
1867 for (i = 0; i < q->num_buffers; i++) {
1868 fileio->bufs[i].vaddr = vb2_plane_vaddr(q->bufs[i], 0);
1869 if (fileio->bufs[i].vaddr == NULL)
1871 fileio->bufs[i].size = vb2_plane_size(q->bufs[i], 0);
1875 * Read mode requires pre queuing of all buffers.
1879 * Queue all buffers.
1881 for (i = 0; i < q->num_buffers; i++) {
1882 struct v4l2_buffer *b = &fileio->b;
1883 memset(b, 0, sizeof(*b));
1885 b->memory = q->memory;
1887 ret = vb2_qbuf(q, b);
1890 fileio->bufs[i].queued = 1;
1896 ret = vb2_streamon(q, q->type);
1906 fileio->req.count = 0;
1907 vb2_reqbufs(q, &fileio->req);
1915 * __vb2_cleanup_fileio() - free resourced used by file io emulator
1916 * @q: videobuf2 queue
1918 static int __vb2_cleanup_fileio(struct vb2_queue *q)
1920 struct vb2_fileio_data *fileio = q->fileio;
1924 * Hack fileio context to enable direct calls to vb2 ioctl
1929 vb2_streamoff(q, q->type);
1930 fileio->req.count = 0;
1931 vb2_reqbufs(q, &fileio->req);
1933 dprintk(3, "file io emulator closed\n");
1939 * __vb2_perform_fileio() - perform a single file io (read or write) operation
1940 * @q: videobuf2 queue
1941 * @data: pointed to target userspace buffer
1942 * @count: number of bytes to read or write
1943 * @ppos: file handle position tracking pointer
1944 * @nonblock: mode selector (1 means blocking calls, 0 means nonblocking)
1945 * @read: access mode selector (1 means read, 0 means write)
1947 static size_t __vb2_perform_fileio(struct vb2_queue *q, char __user *data, size_t count,
1948 loff_t *ppos, int nonblock, int read)
1950 struct vb2_fileio_data *fileio;
1951 struct vb2_fileio_buf *buf;
1954 dprintk(3, "file io: mode %s, offset %ld, count %zd, %sblocking\n",
1955 read ? "read" : "write", (long)*ppos, count,
1956 nonblock ? "non" : "");
1962 * Initialize emulator on first call.
1965 ret = __vb2_init_fileio(q, read);
1966 dprintk(3, "file io: vb2_init_fileio result: %d\n", ret);
1973 * Hack fileio context to enable direct calls to vb2 ioctl interface.
1974 * The pointer will be restored before returning from this function.
1978 index = fileio->index;
1979 buf = &fileio->bufs[index];
1982 * Check if we need to dequeue the buffer.
1985 struct vb2_buffer *vb;
1988 * Call vb2_dqbuf to get buffer back.
1990 memset(&fileio->b, 0, sizeof(fileio->b));
1991 fileio->b.type = q->type;
1992 fileio->b.memory = q->memory;
1993 fileio->b.index = index;
1994 ret = vb2_dqbuf(q, &fileio->b, nonblock);
1995 dprintk(5, "file io: vb2_dqbuf result: %d\n", ret);
1998 fileio->dq_count += 1;
2001 * Get number of bytes filled by the driver
2003 vb = q->bufs[index];
2004 buf->size = vb2_get_plane_payload(vb, 0);
2009 * Limit count on last few bytes of the buffer.
2011 if (buf->pos + count > buf->size) {
2012 count = buf->size - buf->pos;
2013 dprintk(5, "reducing read count: %zd\n", count);
2017 * Transfer data to userspace.
2019 dprintk(3, "file io: copying %zd bytes - buffer %d, offset %u\n",
2020 count, index, buf->pos);
2022 ret = copy_to_user(data, buf->vaddr + buf->pos, count);
2024 ret = copy_from_user(buf->vaddr + buf->pos, data, count);
2026 dprintk(3, "file io: error copying data\n");
2038 * Queue next buffer if required.
2040 if (buf->pos == buf->size ||
2041 (!read && (fileio->flags & VB2_FILEIO_WRITE_IMMEDIATELY))) {
2043 * Check if this is the last buffer to read.
2045 if (read && (fileio->flags & VB2_FILEIO_READ_ONCE) &&
2046 fileio->dq_count == 1) {
2047 dprintk(3, "file io: read limit reached\n");
2049 * Restore fileio pointer and release the context.
2052 return __vb2_cleanup_fileio(q);
2056 * Call vb2_qbuf and give buffer to the driver.
2058 memset(&fileio->b, 0, sizeof(fileio->b));
2059 fileio->b.type = q->type;
2060 fileio->b.memory = q->memory;
2061 fileio->b.index = index;
2062 fileio->b.bytesused = buf->pos;
2063 ret = vb2_qbuf(q, &fileio->b);
2064 dprintk(5, "file io: vb2_dbuf result: %d\n", ret);
2069 * Buffer has been queued, update the status
2073 buf->size = q->bufs[0]->v4l2_planes[0].length;
2074 fileio->q_count += 1;
2077 * Switch to the next buffer
2079 fileio->index = (index + 1) % q->num_buffers;
2082 * Start streaming if required.
2084 if (!read && !q->streaming) {
2085 ret = vb2_streamon(q, q->type);
2092 * Return proper number of bytes processed.
2098 * Restore the fileio context and block vb2 ioctl interface.
2104 size_t vb2_read(struct vb2_queue *q, char __user *data, size_t count,
2105 loff_t *ppos, int nonblocking)
2107 return __vb2_perform_fileio(q, data, count, ppos, nonblocking, 1);
2109 EXPORT_SYMBOL_GPL(vb2_read);
2111 size_t vb2_write(struct vb2_queue *q, char __user *data, size_t count,
2112 loff_t *ppos, int nonblocking)
2114 return __vb2_perform_fileio(q, data, count, ppos, nonblocking, 0);
2116 EXPORT_SYMBOL_GPL(vb2_write);
2118 MODULE_DESCRIPTION("Driver helper framework for Video for Linux 2");
2119 MODULE_AUTHOR("Pawel Osciak <pawel@osciak.com>, Marek Szyprowski");
2120 MODULE_LICENSE("GPL");