2 * videobuf2-core.c - video buffer 2 core framework
4 * Copyright (C) 2010 Samsung Electronics
6 * Author: Pawel Osciak <pawel@osciak.com>
7 * Marek Szyprowski <m.szyprowski@samsung.com>
9 * The vb2_thread implementation was based on code from videobuf-dvb.c:
10 * (c) 2004 Gerd Knorr <kraxel@bytesex.org> [SUSE Labs]
12 * This program is free software; you can redistribute it and/or modify
13 * it under the terms of the GNU General Public License as published by
14 * the Free Software Foundation.
17 #include <linux/err.h>
18 #include <linux/kernel.h>
19 #include <linux/module.h>
21 #include <linux/poll.h>
22 #include <linux/slab.h>
23 #include <linux/sched.h>
24 #include <linux/freezer.h>
25 #include <linux/kthread.h>
27 #include <media/videobuf2-core.h>
29 #include <trace/events/vb2.h>
32 module_param(debug, int, 0644);
34 #define dprintk(level, fmt, arg...) \
37 pr_info("vb2-core: %s: " fmt, __func__, ## arg); \
40 #ifdef CONFIG_VIDEO_ADV_DEBUG
43 * If advanced debugging is on, then count how often each op is called
44 * successfully, which can either be per-buffer or per-queue.
46 * This makes it easy to check that the 'init' and 'cleanup'
47 * (and variations thereof) stay balanced.
50 #define log_memop(vb, op) \
51 dprintk(2, "call_memop(%p, %d, %s)%s\n", \
52 (vb)->vb2_queue, (vb)->index, #op, \
53 (vb)->vb2_queue->mem_ops->op ? "" : " (nop)")
55 #define call_memop(vb, op, args...) \
57 struct vb2_queue *_q = (vb)->vb2_queue; \
61 err = _q->mem_ops->op ? _q->mem_ops->op(args) : 0; \
63 (vb)->cnt_mem_ ## op++; \
67 #define call_ptr_memop(vb, op, args...) \
69 struct vb2_queue *_q = (vb)->vb2_queue; \
73 ptr = _q->mem_ops->op ? _q->mem_ops->op(args) : NULL; \
74 if (!IS_ERR_OR_NULL(ptr)) \
75 (vb)->cnt_mem_ ## op++; \
79 #define call_void_memop(vb, op, args...) \
81 struct vb2_queue *_q = (vb)->vb2_queue; \
84 if (_q->mem_ops->op) \
85 _q->mem_ops->op(args); \
86 (vb)->cnt_mem_ ## op++; \
89 #define log_qop(q, op) \
90 dprintk(2, "call_qop(%p, %s)%s\n", q, #op, \
91 (q)->ops->op ? "" : " (nop)")
93 #define call_qop(q, op, args...) \
98 err = (q)->ops->op ? (q)->ops->op(args) : 0; \
104 #define call_void_qop(q, op, args...) \
108 (q)->ops->op(args); \
112 #define log_vb_qop(vb, op, args...) \
113 dprintk(2, "call_vb_qop(%p, %d, %s)%s\n", \
114 (vb)->vb2_queue, (vb)->index, #op, \
115 (vb)->vb2_queue->ops->op ? "" : " (nop)")
117 #define call_vb_qop(vb, op, args...) \
121 log_vb_qop(vb, op); \
122 err = (vb)->vb2_queue->ops->op ? \
123 (vb)->vb2_queue->ops->op(args) : 0; \
125 (vb)->cnt_ ## op++; \
129 #define call_void_vb_qop(vb, op, args...) \
131 log_vb_qop(vb, op); \
132 if ((vb)->vb2_queue->ops->op) \
133 (vb)->vb2_queue->ops->op(args); \
134 (vb)->cnt_ ## op++; \
139 #define call_memop(vb, op, args...) \
140 ((vb)->vb2_queue->mem_ops->op ? \
141 (vb)->vb2_queue->mem_ops->op(args) : 0)
143 #define call_ptr_memop(vb, op, args...) \
144 ((vb)->vb2_queue->mem_ops->op ? \
145 (vb)->vb2_queue->mem_ops->op(args) : NULL)
147 #define call_void_memop(vb, op, args...) \
149 if ((vb)->vb2_queue->mem_ops->op) \
150 (vb)->vb2_queue->mem_ops->op(args); \
153 #define call_qop(q, op, args...) \
154 ((q)->ops->op ? (q)->ops->op(args) : 0)
156 #define call_void_qop(q, op, args...) \
159 (q)->ops->op(args); \
162 #define call_vb_qop(vb, op, args...) \
163 ((vb)->vb2_queue->ops->op ? (vb)->vb2_queue->ops->op(args) : 0)
165 #define call_void_vb_qop(vb, op, args...) \
167 if ((vb)->vb2_queue->ops->op) \
168 (vb)->vb2_queue->ops->op(args); \
173 #define call_bufop(q, op, args...) \
176 if (q && q->buf_ops && q->buf_ops->op) \
177 ret = q->buf_ops->op(args); \
181 #define call_void_bufop(q, op, args...) \
183 if (q && q->buf_ops && q->buf_ops->op) \
184 q->buf_ops->op(args); \
187 static void __vb2_queue_cancel(struct vb2_queue *q);
188 static void __enqueue_in_driver(struct vb2_buffer *vb);
191 * __vb2_buf_mem_alloc() - allocate video memory for the given buffer
193 static int __vb2_buf_mem_alloc(struct vb2_buffer *vb)
195 struct vb2_queue *q = vb->vb2_queue;
196 enum dma_data_direction dma_dir =
197 q->is_output ? DMA_TO_DEVICE : DMA_FROM_DEVICE;
202 * Allocate memory for all planes in this buffer
203 * NOTE: mmapped areas should be page aligned
205 for (plane = 0; plane < vb->num_planes; ++plane) {
206 unsigned long size = PAGE_ALIGN(vb->planes[plane].length);
208 mem_priv = call_ptr_memop(vb, alloc, q->alloc_ctx[plane],
209 size, dma_dir, q->gfp_flags);
210 if (IS_ERR_OR_NULL(mem_priv))
213 /* Associate allocator private data with this plane */
214 vb->planes[plane].mem_priv = mem_priv;
219 /* Free already allocated memory if one of the allocations failed */
220 for (; plane > 0; --plane) {
221 call_void_memop(vb, put, vb->planes[plane - 1].mem_priv);
222 vb->planes[plane - 1].mem_priv = NULL;
229 * __vb2_buf_mem_free() - free memory of the given buffer
231 static void __vb2_buf_mem_free(struct vb2_buffer *vb)
235 for (plane = 0; plane < vb->num_planes; ++plane) {
236 call_void_memop(vb, put, vb->planes[plane].mem_priv);
237 vb->planes[plane].mem_priv = NULL;
238 dprintk(3, "freed plane %d of buffer %d\n", plane, vb->index);
243 * __vb2_buf_userptr_put() - release userspace memory associated with
246 static void __vb2_buf_userptr_put(struct vb2_buffer *vb)
250 for (plane = 0; plane < vb->num_planes; ++plane) {
251 if (vb->planes[plane].mem_priv)
252 call_void_memop(vb, put_userptr, vb->planes[plane].mem_priv);
253 vb->planes[plane].mem_priv = NULL;
258 * __vb2_plane_dmabuf_put() - release memory associated with
259 * a DMABUF shared plane
261 static void __vb2_plane_dmabuf_put(struct vb2_buffer *vb, struct vb2_plane *p)
267 call_void_memop(vb, unmap_dmabuf, p->mem_priv);
269 call_void_memop(vb, detach_dmabuf, p->mem_priv);
270 dma_buf_put(p->dbuf);
277 * __vb2_buf_dmabuf_put() - release memory associated with
278 * a DMABUF shared buffer
280 static void __vb2_buf_dmabuf_put(struct vb2_buffer *vb)
284 for (plane = 0; plane < vb->num_planes; ++plane)
285 __vb2_plane_dmabuf_put(vb, &vb->planes[plane]);
289 * __setup_offsets() - setup unique offsets ("cookies") for every plane in
292 static void __setup_offsets(struct vb2_buffer *vb)
294 struct vb2_queue *q = vb->vb2_queue;
296 unsigned long off = 0;
299 struct vb2_buffer *prev = q->bufs[vb->index - 1];
300 struct vb2_plane *p = &prev->planes[prev->num_planes - 1];
302 off = PAGE_ALIGN(p->m.offset + p->length);
305 for (plane = 0; plane < vb->num_planes; ++plane) {
306 vb->planes[plane].m.offset = off;
308 dprintk(3, "buffer %d, plane %d offset 0x%08lx\n",
309 vb->index, plane, off);
311 off += vb->planes[plane].length;
312 off = PAGE_ALIGN(off);
317 * __vb2_queue_alloc() - allocate videobuf buffer structures and (for MMAP type)
318 * video buffer memory for all buffers/planes on the queue and initializes the
321 * Returns the number of buffers successfully allocated.
323 static int __vb2_queue_alloc(struct vb2_queue *q, enum vb2_memory memory,
324 unsigned int num_buffers, unsigned int num_planes,
325 const unsigned plane_sizes[VB2_MAX_PLANES])
327 unsigned int buffer, plane;
328 struct vb2_buffer *vb;
331 for (buffer = 0; buffer < num_buffers; ++buffer) {
332 /* Allocate videobuf buffer structures */
333 vb = kzalloc(q->buf_struct_size, GFP_KERNEL);
335 dprintk(1, "memory alloc for buffer struct failed\n");
339 vb->state = VB2_BUF_STATE_DEQUEUED;
341 vb->num_planes = num_planes;
342 vb->index = q->num_buffers + buffer;
345 for (plane = 0; plane < num_planes; ++plane) {
346 vb->planes[plane].length = plane_sizes[plane];
347 vb->planes[plane].min_length = plane_sizes[plane];
349 q->bufs[vb->index] = vb;
351 /* Allocate video buffer memory for the MMAP type */
352 if (memory == VB2_MEMORY_MMAP) {
353 ret = __vb2_buf_mem_alloc(vb);
355 dprintk(1, "failed allocating memory for "
356 "buffer %d\n", buffer);
357 q->bufs[vb->index] = NULL;
363 * Call the driver-provided buffer initialization
364 * callback, if given. An error in initialization
365 * results in queue setup failure.
367 ret = call_vb_qop(vb, buf_init, vb);
369 dprintk(1, "buffer %d %p initialization"
370 " failed\n", buffer, vb);
371 __vb2_buf_mem_free(vb);
372 q->bufs[vb->index] = NULL;
379 dprintk(1, "allocated %d buffers, %d plane(s) each\n",
386 * __vb2_free_mem() - release all video buffer memory for a given queue
388 static void __vb2_free_mem(struct vb2_queue *q, unsigned int buffers)
391 struct vb2_buffer *vb;
393 for (buffer = q->num_buffers - buffers; buffer < q->num_buffers;
395 vb = q->bufs[buffer];
399 /* Free MMAP buffers or release USERPTR buffers */
400 if (q->memory == VB2_MEMORY_MMAP)
401 __vb2_buf_mem_free(vb);
402 else if (q->memory == VB2_MEMORY_DMABUF)
403 __vb2_buf_dmabuf_put(vb);
405 __vb2_buf_userptr_put(vb);
410 * __vb2_queue_free() - free buffers at the end of the queue - video memory and
411 * related information, if no buffers are left return the queue to an
412 * uninitialized state. Might be called even if the queue has already been freed.
414 static int __vb2_queue_free(struct vb2_queue *q, unsigned int buffers)
419 * Sanity check: when preparing a buffer the queue lock is released for
420 * a short while (see __buf_prepare for the details), which would allow
421 * a race with a reqbufs which can call this function. Removing the
422 * buffers from underneath __buf_prepare is obviously a bad idea, so we
423 * check if any of the buffers is in the state PREPARING, and if so we
424 * just return -EAGAIN.
426 for (buffer = q->num_buffers - buffers; buffer < q->num_buffers;
428 if (q->bufs[buffer] == NULL)
430 if (q->bufs[buffer]->state == VB2_BUF_STATE_PREPARING) {
431 dprintk(1, "preparing buffers, cannot free\n");
436 /* Call driver-provided cleanup function for each buffer, if provided */
437 for (buffer = q->num_buffers - buffers; buffer < q->num_buffers;
439 struct vb2_buffer *vb = q->bufs[buffer];
441 if (vb && vb->planes[0].mem_priv)
442 call_void_vb_qop(vb, buf_cleanup, vb);
445 /* Release video buffer memory */
446 __vb2_free_mem(q, buffers);
448 #ifdef CONFIG_VIDEO_ADV_DEBUG
450 * Check that all the calls were balances during the life-time of this
451 * queue. If not (or if the debug level is 1 or up), then dump the
452 * counters to the kernel log.
454 if (q->num_buffers) {
455 bool unbalanced = q->cnt_start_streaming != q->cnt_stop_streaming ||
456 q->cnt_wait_prepare != q->cnt_wait_finish;
458 if (unbalanced || debug) {
459 pr_info("vb2: counters for queue %p:%s\n", q,
460 unbalanced ? " UNBALANCED!" : "");
461 pr_info("vb2: setup: %u start_streaming: %u stop_streaming: %u\n",
462 q->cnt_queue_setup, q->cnt_start_streaming,
463 q->cnt_stop_streaming);
464 pr_info("vb2: wait_prepare: %u wait_finish: %u\n",
465 q->cnt_wait_prepare, q->cnt_wait_finish);
467 q->cnt_queue_setup = 0;
468 q->cnt_wait_prepare = 0;
469 q->cnt_wait_finish = 0;
470 q->cnt_start_streaming = 0;
471 q->cnt_stop_streaming = 0;
473 for (buffer = 0; buffer < q->num_buffers; ++buffer) {
474 struct vb2_buffer *vb = q->bufs[buffer];
475 bool unbalanced = vb->cnt_mem_alloc != vb->cnt_mem_put ||
476 vb->cnt_mem_prepare != vb->cnt_mem_finish ||
477 vb->cnt_mem_get_userptr != vb->cnt_mem_put_userptr ||
478 vb->cnt_mem_attach_dmabuf != vb->cnt_mem_detach_dmabuf ||
479 vb->cnt_mem_map_dmabuf != vb->cnt_mem_unmap_dmabuf ||
480 vb->cnt_buf_queue != vb->cnt_buf_done ||
481 vb->cnt_buf_prepare != vb->cnt_buf_finish ||
482 vb->cnt_buf_init != vb->cnt_buf_cleanup;
484 if (unbalanced || debug) {
485 pr_info("vb2: counters for queue %p, buffer %d:%s\n",
486 q, buffer, unbalanced ? " UNBALANCED!" : "");
487 pr_info("vb2: buf_init: %u buf_cleanup: %u buf_prepare: %u buf_finish: %u\n",
488 vb->cnt_buf_init, vb->cnt_buf_cleanup,
489 vb->cnt_buf_prepare, vb->cnt_buf_finish);
490 pr_info("vb2: buf_queue: %u buf_done: %u\n",
491 vb->cnt_buf_queue, vb->cnt_buf_done);
492 pr_info("vb2: alloc: %u put: %u prepare: %u finish: %u mmap: %u\n",
493 vb->cnt_mem_alloc, vb->cnt_mem_put,
494 vb->cnt_mem_prepare, vb->cnt_mem_finish,
496 pr_info("vb2: get_userptr: %u put_userptr: %u\n",
497 vb->cnt_mem_get_userptr, vb->cnt_mem_put_userptr);
498 pr_info("vb2: attach_dmabuf: %u detach_dmabuf: %u map_dmabuf: %u unmap_dmabuf: %u\n",
499 vb->cnt_mem_attach_dmabuf, vb->cnt_mem_detach_dmabuf,
500 vb->cnt_mem_map_dmabuf, vb->cnt_mem_unmap_dmabuf);
501 pr_info("vb2: get_dmabuf: %u num_users: %u vaddr: %u cookie: %u\n",
502 vb->cnt_mem_get_dmabuf,
503 vb->cnt_mem_num_users,
510 /* Free videobuf buffers */
511 for (buffer = q->num_buffers - buffers; buffer < q->num_buffers;
513 kfree(q->bufs[buffer]);
514 q->bufs[buffer] = NULL;
517 q->num_buffers -= buffers;
518 if (!q->num_buffers) {
520 INIT_LIST_HEAD(&q->queued_list);
526 * vb2_buffer_in_use() - return true if the buffer is in use and
527 * the queue cannot be freed (by the means of REQBUFS(0)) call
529 bool vb2_buffer_in_use(struct vb2_queue *q, struct vb2_buffer *vb)
532 for (plane = 0; plane < vb->num_planes; ++plane) {
533 void *mem_priv = vb->planes[plane].mem_priv;
535 * If num_users() has not been provided, call_memop
536 * will return 0, apparently nobody cares about this
537 * case anyway. If num_users() returns more than 1,
538 * we are not the only user of the plane's memory.
540 if (mem_priv && call_memop(vb, num_users, mem_priv) > 1)
545 EXPORT_SYMBOL(vb2_buffer_in_use);
548 * __buffers_in_use() - return true if any buffers on the queue are in use and
549 * the queue cannot be freed (by the means of REQBUFS(0)) call
551 static bool __buffers_in_use(struct vb2_queue *q)
554 for (buffer = 0; buffer < q->num_buffers; ++buffer) {
555 if (vb2_buffer_in_use(q, q->bufs[buffer]))
562 * vb2_core_querybuf() - query video buffer information
564 * @index: id number of the buffer
565 * @pb: buffer struct passed from userspace
567 * Should be called from vidioc_querybuf ioctl handler in driver.
568 * The passed buffer should have been verified.
569 * This function fills the relevant information for the userspace.
571 void vb2_core_querybuf(struct vb2_queue *q, unsigned int index, void *pb)
573 call_void_bufop(q, fill_user_buffer, q->bufs[index], pb);
575 EXPORT_SYMBOL_GPL(vb2_core_querybuf);
578 * __verify_userptr_ops() - verify that all memory operations required for
579 * USERPTR queue type have been provided
581 static int __verify_userptr_ops(struct vb2_queue *q)
583 if (!(q->io_modes & VB2_USERPTR) || !q->mem_ops->get_userptr ||
584 !q->mem_ops->put_userptr)
591 * __verify_mmap_ops() - verify that all memory operations required for
592 * MMAP queue type have been provided
594 static int __verify_mmap_ops(struct vb2_queue *q)
596 if (!(q->io_modes & VB2_MMAP) || !q->mem_ops->alloc ||
597 !q->mem_ops->put || !q->mem_ops->mmap)
604 * __verify_dmabuf_ops() - verify that all memory operations required for
605 * DMABUF queue type have been provided
607 static int __verify_dmabuf_ops(struct vb2_queue *q)
609 if (!(q->io_modes & VB2_DMABUF) || !q->mem_ops->attach_dmabuf ||
610 !q->mem_ops->detach_dmabuf || !q->mem_ops->map_dmabuf ||
611 !q->mem_ops->unmap_dmabuf)
618 * vb2_verify_memory_type() - Check whether the memory type and buffer type
619 * passed to a buffer operation are compatible with the queue.
621 int vb2_verify_memory_type(struct vb2_queue *q,
622 enum vb2_memory memory, unsigned int type)
624 if (memory != VB2_MEMORY_MMAP && memory != VB2_MEMORY_USERPTR &&
625 memory != VB2_MEMORY_DMABUF) {
626 dprintk(1, "unsupported memory type\n");
630 if (type != q->type) {
631 dprintk(1, "requested type is incorrect\n");
636 * Make sure all the required memory ops for given memory type
639 if (memory == VB2_MEMORY_MMAP && __verify_mmap_ops(q)) {
640 dprintk(1, "MMAP for current setup unsupported\n");
644 if (memory == VB2_MEMORY_USERPTR && __verify_userptr_ops(q)) {
645 dprintk(1, "USERPTR for current setup unsupported\n");
649 if (memory == VB2_MEMORY_DMABUF && __verify_dmabuf_ops(q)) {
650 dprintk(1, "DMABUF for current setup unsupported\n");
655 * Place the busy tests at the end: -EBUSY can be ignored when
656 * create_bufs is called with count == 0, but count == 0 should still
657 * do the memory and type validation.
659 if (vb2_fileio_is_active(q)) {
660 dprintk(1, "file io in progress\n");
665 EXPORT_SYMBOL(vb2_verify_memory_type);
668 * vb2_core_reqbufs() - Initiate streaming
669 * @q: videobuf2 queue
670 * @memory: memory type
671 * @count: requested buffer count
673 * Should be called from vidioc_reqbufs ioctl handler of a driver.
675 * 1) verifies streaming parameters passed from the userspace,
676 * 2) sets up the queue,
677 * 3) negotiates number of buffers and planes per buffer with the driver
678 * to be used during streaming,
679 * 4) allocates internal buffer structures (struct vb2_buffer), according to
680 * the agreed parameters,
681 * 5) for MMAP memory type, allocates actual video memory, using the
682 * memory handling/allocation routines provided during queue initialization
684 * If req->count is 0, all the memory will be freed instead.
685 * If the queue has been allocated previously (by a previous vb2_reqbufs) call
686 * and the queue is not busy, memory will be reallocated.
688 * The return values from this function are intended to be directly returned
689 * from vidioc_reqbufs handler in driver.
691 int vb2_core_reqbufs(struct vb2_queue *q, enum vb2_memory memory,
694 unsigned int num_buffers, allocated_buffers, num_planes = 0;
695 unsigned plane_sizes[VB2_MAX_PLANES] = { };
699 dprintk(1, "streaming active\n");
703 if (*count == 0 || q->num_buffers != 0 || q->memory != memory) {
705 * We already have buffers allocated, so first check if they
706 * are not in use and can be freed.
708 mutex_lock(&q->mmap_lock);
709 if (q->memory == VB2_MEMORY_MMAP && __buffers_in_use(q)) {
710 mutex_unlock(&q->mmap_lock);
711 dprintk(1, "memory in use, cannot free\n");
716 * Call queue_cancel to clean up any buffers in the PREPARED or
717 * QUEUED state which is possible if buffers were prepared or
718 * queued without ever calling STREAMON.
720 __vb2_queue_cancel(q);
721 ret = __vb2_queue_free(q, q->num_buffers);
722 mutex_unlock(&q->mmap_lock);
727 * In case of REQBUFS(0) return immediately without calling
728 * driver's queue_setup() callback and allocating resources.
735 * Make sure the requested values and current defaults are sane.
737 num_buffers = min_t(unsigned int, *count, VB2_MAX_FRAME);
738 num_buffers = max_t(unsigned int, num_buffers, q->min_buffers_needed);
739 memset(q->alloc_ctx, 0, sizeof(q->alloc_ctx));
743 * Ask the driver how many buffers and planes per buffer it requires.
744 * Driver also sets the size and allocator context for each plane.
746 ret = call_qop(q, queue_setup, q, &num_buffers, &num_planes,
747 plane_sizes, q->alloc_ctx);
751 /* Finally, allocate buffers and video memory */
753 __vb2_queue_alloc(q, memory, num_buffers, num_planes, plane_sizes);
754 if (allocated_buffers == 0) {
755 dprintk(1, "memory allocation failed\n");
760 * There is no point in continuing if we can't allocate the minimum
761 * number of buffers needed by this vb2_queue.
763 if (allocated_buffers < q->min_buffers_needed)
767 * Check if driver can handle the allocated number of buffers.
769 if (!ret && allocated_buffers < num_buffers) {
770 num_buffers = allocated_buffers;
772 * num_planes is set by the previous queue_setup(), but since it
773 * signals to queue_setup() whether it is called from create_bufs()
774 * vs reqbufs() we zero it here to signal that queue_setup() is
775 * called for the reqbufs() case.
779 ret = call_qop(q, queue_setup, q, &num_buffers,
780 &num_planes, plane_sizes, q->alloc_ctx);
782 if (!ret && allocated_buffers < num_buffers)
786 * Either the driver has accepted a smaller number of buffers,
787 * or .queue_setup() returned an error
791 mutex_lock(&q->mmap_lock);
792 q->num_buffers = allocated_buffers;
796 * Note: __vb2_queue_free() will subtract 'allocated_buffers'
797 * from q->num_buffers.
799 __vb2_queue_free(q, allocated_buffers);
800 mutex_unlock(&q->mmap_lock);
803 mutex_unlock(&q->mmap_lock);
806 * Return the number of successfully allocated buffers
809 *count = allocated_buffers;
810 q->waiting_for_buffers = !q->is_output;
814 EXPORT_SYMBOL_GPL(vb2_core_reqbufs);
817 * vb2_core_create_bufs() - Allocate buffers and any required auxiliary structs
818 * @q: videobuf2 queue
819 * @memory: memory type
820 * @count: requested buffer count
821 * @parg: parameter passed to device driver
823 * Should be called from vidioc_create_bufs ioctl handler of a driver.
825 * 1) verifies parameter sanity
826 * 2) calls the .queue_setup() queue operation
827 * 3) performs any necessary memory allocations
829 * The return values from this function are intended to be directly returned
830 * from vidioc_create_bufs handler in driver.
832 int vb2_core_create_bufs(struct vb2_queue *q, enum vb2_memory memory,
833 unsigned int *count, unsigned requested_planes,
834 const unsigned requested_sizes[])
836 unsigned int num_planes = 0, num_buffers, allocated_buffers;
837 unsigned plane_sizes[VB2_MAX_PLANES] = { };
840 if (q->num_buffers == VB2_MAX_FRAME) {
841 dprintk(1, "maximum number of buffers already allocated\n");
845 if (!q->num_buffers) {
846 memset(q->alloc_ctx, 0, sizeof(q->alloc_ctx));
848 q->waiting_for_buffers = !q->is_output;
851 num_buffers = min(*count, VB2_MAX_FRAME - q->num_buffers);
853 if (requested_planes && requested_sizes) {
854 num_planes = requested_planes;
855 memcpy(plane_sizes, requested_sizes, sizeof(plane_sizes));
859 * Ask the driver, whether the requested number of buffers, planes per
860 * buffer and their sizes are acceptable
862 ret = call_qop(q, queue_setup, q, &num_buffers,
863 &num_planes, plane_sizes, q->alloc_ctx);
867 /* Finally, allocate buffers and video memory */
868 allocated_buffers = __vb2_queue_alloc(q, memory, num_buffers,
869 num_planes, plane_sizes);
870 if (allocated_buffers == 0) {
871 dprintk(1, "memory allocation failed\n");
876 * Check if driver can handle the so far allocated number of buffers.
878 if (allocated_buffers < num_buffers) {
879 num_buffers = allocated_buffers;
882 * q->num_buffers contains the total number of buffers, that the
883 * queue driver has set up
885 ret = call_qop(q, queue_setup, q, &num_buffers,
886 &num_planes, plane_sizes, q->alloc_ctx);
888 if (!ret && allocated_buffers < num_buffers)
892 * Either the driver has accepted a smaller number of buffers,
893 * or .queue_setup() returned an error
897 mutex_lock(&q->mmap_lock);
898 q->num_buffers += allocated_buffers;
902 * Note: __vb2_queue_free() will subtract 'allocated_buffers'
903 * from q->num_buffers.
905 __vb2_queue_free(q, allocated_buffers);
906 mutex_unlock(&q->mmap_lock);
909 mutex_unlock(&q->mmap_lock);
912 * Return the number of successfully allocated buffers
915 *count = allocated_buffers;
919 EXPORT_SYMBOL_GPL(vb2_core_create_bufs);
922 * vb2_plane_vaddr() - Return a kernel virtual address of a given plane
923 * @vb: vb2_buffer to which the plane in question belongs to
924 * @plane_no: plane number for which the address is to be returned
926 * This function returns a kernel virtual address of a given plane if
927 * such a mapping exist, NULL otherwise.
929 void *vb2_plane_vaddr(struct vb2_buffer *vb, unsigned int plane_no)
931 if (plane_no > vb->num_planes || !vb->planes[plane_no].mem_priv)
934 return call_ptr_memop(vb, vaddr, vb->planes[plane_no].mem_priv);
937 EXPORT_SYMBOL_GPL(vb2_plane_vaddr);
940 * vb2_plane_cookie() - Return allocator specific cookie for the given plane
941 * @vb: vb2_buffer to which the plane in question belongs to
942 * @plane_no: plane number for which the cookie is to be returned
944 * This function returns an allocator specific cookie for a given plane if
945 * available, NULL otherwise. The allocator should provide some simple static
946 * inline function, which would convert this cookie to the allocator specific
947 * type that can be used directly by the driver to access the buffer. This can
948 * be for example physical address, pointer to scatter list or IOMMU mapping.
950 void *vb2_plane_cookie(struct vb2_buffer *vb, unsigned int plane_no)
952 if (plane_no >= vb->num_planes || !vb->planes[plane_no].mem_priv)
955 return call_ptr_memop(vb, cookie, vb->planes[plane_no].mem_priv);
957 EXPORT_SYMBOL_GPL(vb2_plane_cookie);
960 * vb2_buffer_done() - inform videobuf that an operation on a buffer is finished
961 * @vb: vb2_buffer returned from the driver
962 * @state: either VB2_BUF_STATE_DONE if the operation finished successfully,
963 * VB2_BUF_STATE_ERROR if the operation finished with an error or
964 * VB2_BUF_STATE_QUEUED if the driver wants to requeue buffers.
965 * If start_streaming fails then it should return buffers with state
966 * VB2_BUF_STATE_QUEUED to put them back into the queue.
968 * This function should be called by the driver after a hardware operation on
969 * a buffer is finished and the buffer may be returned to userspace. The driver
970 * cannot use this buffer anymore until it is queued back to it by videobuf
971 * by the means of buf_queue callback. Only buffers previously queued to the
972 * driver by buf_queue can be passed to this function.
974 * While streaming a buffer can only be returned in state DONE or ERROR.
975 * The start_streaming op can also return them in case the DMA engine cannot
976 * be started for some reason. In that case the buffers should be returned with
979 void vb2_buffer_done(struct vb2_buffer *vb, enum vb2_buffer_state state)
981 struct vb2_queue *q = vb->vb2_queue;
985 if (WARN_ON(vb->state != VB2_BUF_STATE_ACTIVE))
988 if (WARN_ON(state != VB2_BUF_STATE_DONE &&
989 state != VB2_BUF_STATE_ERROR &&
990 state != VB2_BUF_STATE_QUEUED &&
991 state != VB2_BUF_STATE_REQUEUEING))
992 state = VB2_BUF_STATE_ERROR;
994 #ifdef CONFIG_VIDEO_ADV_DEBUG
996 * Although this is not a callback, it still does have to balance
997 * with the buf_queue op. So update this counter manually.
1001 dprintk(4, "done processing on buffer %d, state: %d\n",
1005 for (plane = 0; plane < vb->num_planes; ++plane)
1006 call_void_memop(vb, finish, vb->planes[plane].mem_priv);
1008 spin_lock_irqsave(&q->done_lock, flags);
1009 if (state == VB2_BUF_STATE_QUEUED ||
1010 state == VB2_BUF_STATE_REQUEUEING) {
1011 vb->state = VB2_BUF_STATE_QUEUED;
1013 /* Add the buffer to the done buffers list */
1014 list_add_tail(&vb->done_entry, &q->done_list);
1017 atomic_dec(&q->owned_by_drv_count);
1018 spin_unlock_irqrestore(&q->done_lock, flags);
1020 trace_vb2_buf_done(q, vb);
1023 case VB2_BUF_STATE_QUEUED:
1025 case VB2_BUF_STATE_REQUEUEING:
1026 if (q->start_streaming_called)
1027 __enqueue_in_driver(vb);
1030 /* Inform any processes that may be waiting for buffers */
1031 wake_up(&q->done_wq);
1035 EXPORT_SYMBOL_GPL(vb2_buffer_done);
1038 * vb2_discard_done() - discard all buffers marked as DONE
1039 * @q: videobuf2 queue
1041 * This function is intended to be used with suspend/resume operations. It
1042 * discards all 'done' buffers as they would be too old to be requested after
1045 * Drivers must stop the hardware and synchronize with interrupt handlers and/or
1046 * delayed works before calling this function to make sure no buffer will be
1047 * touched by the driver and/or hardware.
1049 void vb2_discard_done(struct vb2_queue *q)
1051 struct vb2_buffer *vb;
1052 unsigned long flags;
1054 spin_lock_irqsave(&q->done_lock, flags);
1055 list_for_each_entry(vb, &q->done_list, done_entry)
1056 vb->state = VB2_BUF_STATE_ERROR;
1057 spin_unlock_irqrestore(&q->done_lock, flags);
1059 EXPORT_SYMBOL_GPL(vb2_discard_done);
1062 * __qbuf_mmap() - handle qbuf of an MMAP buffer
1064 static int __qbuf_mmap(struct vb2_buffer *vb, const void *pb)
1069 ret = call_bufop(vb->vb2_queue, fill_vb2_buffer,
1070 vb, pb, vb->planes);
1071 return ret ? ret : call_vb_qop(vb, buf_prepare, vb);
1075 * __qbuf_userptr() - handle qbuf of a USERPTR buffer
1077 static int __qbuf_userptr(struct vb2_buffer *vb, const void *pb)
1079 struct vb2_plane planes[VB2_MAX_PLANES];
1080 struct vb2_queue *q = vb->vb2_queue;
1084 enum dma_data_direction dma_dir =
1085 q->is_output ? DMA_TO_DEVICE : DMA_FROM_DEVICE;
1086 bool reacquired = vb->planes[0].mem_priv == NULL;
1088 memset(planes, 0, sizeof(planes[0]) * vb->num_planes);
1089 /* Copy relevant information provided by the userspace */
1091 ret = call_bufop(vb->vb2_queue, fill_vb2_buffer,
1096 for (plane = 0; plane < vb->num_planes; ++plane) {
1097 /* Skip the plane if already verified */
1098 if (vb->planes[plane].m.userptr &&
1099 vb->planes[plane].m.userptr == planes[plane].m.userptr
1100 && vb->planes[plane].length == planes[plane].length)
1103 dprintk(3, "userspace address for plane %d changed, "
1104 "reacquiring memory\n", plane);
1106 /* Check if the provided plane buffer is large enough */
1107 if (planes[plane].length < vb->planes[plane].min_length) {
1108 dprintk(1, "provided buffer size %u is less than "
1109 "setup size %u for plane %d\n",
1110 planes[plane].length,
1111 vb->planes[plane].min_length,
1117 /* Release previously acquired memory if present */
1118 if (vb->planes[plane].mem_priv) {
1121 call_void_vb_qop(vb, buf_cleanup, vb);
1123 call_void_memop(vb, put_userptr, vb->planes[plane].mem_priv);
1126 vb->planes[plane].mem_priv = NULL;
1127 vb->planes[plane].bytesused = 0;
1128 vb->planes[plane].length = 0;
1129 vb->planes[plane].m.userptr = 0;
1130 vb->planes[plane].data_offset = 0;
1132 /* Acquire each plane's memory */
1133 mem_priv = call_ptr_memop(vb, get_userptr, q->alloc_ctx[plane],
1134 planes[plane].m.userptr,
1135 planes[plane].length, dma_dir);
1136 if (IS_ERR_OR_NULL(mem_priv)) {
1137 dprintk(1, "failed acquiring userspace "
1138 "memory for plane %d\n", plane);
1139 ret = mem_priv ? PTR_ERR(mem_priv) : -EINVAL;
1142 vb->planes[plane].mem_priv = mem_priv;
1146 * Now that everything is in order, copy relevant information
1147 * provided by userspace.
1149 for (plane = 0; plane < vb->num_planes; ++plane) {
1150 vb->planes[plane].bytesused = planes[plane].bytesused;
1151 vb->planes[plane].length = planes[plane].length;
1152 vb->planes[plane].m.userptr = planes[plane].m.userptr;
1153 vb->planes[plane].data_offset = planes[plane].data_offset;
1158 * One or more planes changed, so we must call buf_init to do
1159 * the driver-specific initialization on the newly acquired
1160 * buffer, if provided.
1162 ret = call_vb_qop(vb, buf_init, vb);
1164 dprintk(1, "buffer initialization failed\n");
1169 ret = call_vb_qop(vb, buf_prepare, vb);
1171 dprintk(1, "buffer preparation failed\n");
1172 call_void_vb_qop(vb, buf_cleanup, vb);
1178 /* In case of errors, release planes that were already acquired */
1179 for (plane = 0; plane < vb->num_planes; ++plane) {
1180 if (vb->planes[plane].mem_priv)
1181 call_void_memop(vb, put_userptr,
1182 vb->planes[plane].mem_priv);
1183 vb->planes[plane].mem_priv = NULL;
1184 vb->planes[plane].m.userptr = 0;
1185 vb->planes[plane].length = 0;
1192 * __qbuf_dmabuf() - handle qbuf of a DMABUF buffer
1194 static int __qbuf_dmabuf(struct vb2_buffer *vb, const void *pb)
1196 struct vb2_plane planes[VB2_MAX_PLANES];
1197 struct vb2_queue *q = vb->vb2_queue;
1201 enum dma_data_direction dma_dir =
1202 q->is_output ? DMA_TO_DEVICE : DMA_FROM_DEVICE;
1203 bool reacquired = vb->planes[0].mem_priv == NULL;
1205 memset(planes, 0, sizeof(planes[0]) * vb->num_planes);
1206 /* Copy relevant information provided by the userspace */
1208 ret = call_bufop(vb->vb2_queue, fill_vb2_buffer,
1213 for (plane = 0; plane < vb->num_planes; ++plane) {
1214 struct dma_buf *dbuf = dma_buf_get(planes[plane].m.fd);
1216 if (IS_ERR_OR_NULL(dbuf)) {
1217 dprintk(1, "invalid dmabuf fd for plane %d\n",
1223 /* use DMABUF size if length is not provided */
1224 if (planes[plane].length == 0)
1225 planes[plane].length = dbuf->size;
1227 if (planes[plane].length < vb->planes[plane].min_length) {
1228 dprintk(1, "invalid dmabuf length for plane %d\n",
1235 /* Skip the plane if already verified */
1236 if (dbuf == vb->planes[plane].dbuf &&
1237 vb->planes[plane].length == planes[plane].length) {
1242 dprintk(1, "buffer for plane %d changed\n", plane);
1246 call_void_vb_qop(vb, buf_cleanup, vb);
1249 /* Release previously acquired memory if present */
1250 __vb2_plane_dmabuf_put(vb, &vb->planes[plane]);
1251 vb->planes[plane].bytesused = 0;
1252 vb->planes[plane].length = 0;
1253 vb->planes[plane].m.fd = 0;
1254 vb->planes[plane].data_offset = 0;
1256 /* Acquire each plane's memory */
1257 mem_priv = call_ptr_memop(vb, attach_dmabuf,
1258 q->alloc_ctx[plane], dbuf, planes[plane].length,
1260 if (IS_ERR(mem_priv)) {
1261 dprintk(1, "failed to attach dmabuf\n");
1262 ret = PTR_ERR(mem_priv);
1267 vb->planes[plane].dbuf = dbuf;
1268 vb->planes[plane].mem_priv = mem_priv;
1271 /* TODO: This pins the buffer(s) with dma_buf_map_attachment()).. but
1272 * really we want to do this just before the DMA, not while queueing
1275 for (plane = 0; plane < vb->num_planes; ++plane) {
1276 ret = call_memop(vb, map_dmabuf, vb->planes[plane].mem_priv);
1278 dprintk(1, "failed to map dmabuf for plane %d\n",
1282 vb->planes[plane].dbuf_mapped = 1;
1286 * Now that everything is in order, copy relevant information
1287 * provided by userspace.
1289 for (plane = 0; plane < vb->num_planes; ++plane) {
1290 vb->planes[plane].bytesused = planes[plane].bytesused;
1291 vb->planes[plane].length = planes[plane].length;
1292 vb->planes[plane].m.fd = planes[plane].m.fd;
1293 vb->planes[plane].data_offset = planes[plane].data_offset;
1298 * Call driver-specific initialization on the newly acquired buffer,
1301 ret = call_vb_qop(vb, buf_init, vb);
1303 dprintk(1, "buffer initialization failed\n");
1308 ret = call_vb_qop(vb, buf_prepare, vb);
1310 dprintk(1, "buffer preparation failed\n");
1311 call_void_vb_qop(vb, buf_cleanup, vb);
1317 /* In case of errors, release planes that were already acquired */
1318 __vb2_buf_dmabuf_put(vb);
1324 * __enqueue_in_driver() - enqueue a vb2_buffer in driver for processing
1326 static void __enqueue_in_driver(struct vb2_buffer *vb)
1328 struct vb2_queue *q = vb->vb2_queue;
1331 vb->state = VB2_BUF_STATE_ACTIVE;
1332 atomic_inc(&q->owned_by_drv_count);
1334 trace_vb2_buf_queue(q, vb);
1337 for (plane = 0; plane < vb->num_planes; ++plane)
1338 call_void_memop(vb, prepare, vb->planes[plane].mem_priv);
1340 call_void_vb_qop(vb, buf_queue, vb);
1343 static int __buf_prepare(struct vb2_buffer *vb, const void *pb)
1345 struct vb2_queue *q = vb->vb2_queue;
1349 dprintk(1, "fatal error occurred on queue\n");
1353 vb->state = VB2_BUF_STATE_PREPARING;
1355 switch (q->memory) {
1356 case VB2_MEMORY_MMAP:
1357 ret = __qbuf_mmap(vb, pb);
1359 case VB2_MEMORY_USERPTR:
1360 ret = __qbuf_userptr(vb, pb);
1362 case VB2_MEMORY_DMABUF:
1363 ret = __qbuf_dmabuf(vb, pb);
1366 WARN(1, "Invalid queue type\n");
1371 dprintk(1, "buffer preparation failed: %d\n", ret);
1372 vb->state = ret ? VB2_BUF_STATE_DEQUEUED : VB2_BUF_STATE_PREPARED;
1378 * vb2_core_prepare_buf() - Pass ownership of a buffer from userspace
1380 * @q: videobuf2 queue
1381 * @index: id number of the buffer
1382 * @pb: buffer structure passed from userspace to vidioc_prepare_buf
1385 * Should be called from vidioc_prepare_buf ioctl handler of a driver.
1386 * The passed buffer should have been verified.
1387 * This function calls buf_prepare callback in the driver (if provided),
1388 * in which driver-specific buffer initialization can be performed,
1390 * The return values from this function are intended to be directly returned
1391 * from vidioc_prepare_buf handler in driver.
1393 int vb2_core_prepare_buf(struct vb2_queue *q, unsigned int index, void *pb)
1395 struct vb2_buffer *vb;
1398 vb = q->bufs[index];
1399 if (vb->state != VB2_BUF_STATE_DEQUEUED) {
1400 dprintk(1, "invalid buffer state %d\n",
1405 ret = __buf_prepare(vb, pb);
1409 /* Fill buffer information for the userspace */
1410 call_void_bufop(q, fill_user_buffer, vb, pb);
1412 dprintk(1, "prepare of buffer %d succeeded\n", vb->index);
1416 EXPORT_SYMBOL_GPL(vb2_core_prepare_buf);
1419 * vb2_start_streaming() - Attempt to start streaming.
1420 * @q: videobuf2 queue
1422 * Attempt to start streaming. When this function is called there must be
1423 * at least q->min_buffers_needed buffers queued up (i.e. the minimum
1424 * number of buffers required for the DMA engine to function). If the
1425 * @start_streaming op fails it is supposed to return all the driver-owned
1426 * buffers back to vb2 in state QUEUED. Check if that happened and if
1427 * not warn and reclaim them forcefully.
1429 static int vb2_start_streaming(struct vb2_queue *q)
1431 struct vb2_buffer *vb;
1435 * If any buffers were queued before streamon,
1436 * we can now pass them to driver for processing.
1438 list_for_each_entry(vb, &q->queued_list, queued_entry)
1439 __enqueue_in_driver(vb);
1441 /* Tell the driver to start streaming */
1442 q->start_streaming_called = 1;
1443 ret = call_qop(q, start_streaming, q,
1444 atomic_read(&q->owned_by_drv_count));
1448 q->start_streaming_called = 0;
1450 dprintk(1, "driver refused to start streaming\n");
1452 * If you see this warning, then the driver isn't cleaning up properly
1453 * after a failed start_streaming(). See the start_streaming()
1454 * documentation in videobuf2-core.h for more information how buffers
1455 * should be returned to vb2 in start_streaming().
1457 if (WARN_ON(atomic_read(&q->owned_by_drv_count))) {
1461 * Forcefully reclaim buffers if the driver did not
1462 * correctly return them to vb2.
1464 for (i = 0; i < q->num_buffers; ++i) {
1466 if (vb->state == VB2_BUF_STATE_ACTIVE)
1467 vb2_buffer_done(vb, VB2_BUF_STATE_QUEUED);
1469 /* Must be zero now */
1470 WARN_ON(atomic_read(&q->owned_by_drv_count));
1473 * If done_list is not empty, then start_streaming() didn't call
1474 * vb2_buffer_done(vb, VB2_BUF_STATE_QUEUED) but STATE_ERROR or
1477 WARN_ON(!list_empty(&q->done_list));
1482 * vb2_core_qbuf() - Queue a buffer from userspace
1483 * @q: videobuf2 queue
1484 * @index: id number of the buffer
1485 * @pb: buffer structure passed from userspace to vidioc_qbuf handler
1488 * Should be called from vidioc_qbuf ioctl handler of a driver.
1489 * The passed buffer should have been verified.
1491 * 1) if necessary, calls buf_prepare callback in the driver (if provided), in
1492 * which driver-specific buffer initialization can be performed,
1493 * 2) if streaming is on, queues the buffer in driver by the means of buf_queue
1494 * callback for processing.
1496 * The return values from this function are intended to be directly returned
1497 * from vidioc_qbuf handler in driver.
1499 int vb2_core_qbuf(struct vb2_queue *q, unsigned int index, void *pb)
1501 struct vb2_buffer *vb;
1504 vb = q->bufs[index];
1506 switch (vb->state) {
1507 case VB2_BUF_STATE_DEQUEUED:
1508 ret = __buf_prepare(vb, pb);
1512 case VB2_BUF_STATE_PREPARED:
1514 case VB2_BUF_STATE_PREPARING:
1515 dprintk(1, "buffer still being prepared\n");
1518 dprintk(1, "invalid buffer state %d\n", vb->state);
1523 * Add to the queued buffers list, a buffer will stay on it until
1524 * dequeued in dqbuf.
1526 list_add_tail(&vb->queued_entry, &q->queued_list);
1528 q->waiting_for_buffers = false;
1529 vb->state = VB2_BUF_STATE_QUEUED;
1532 call_void_bufop(q, copy_timestamp, vb, pb);
1534 trace_vb2_qbuf(q, vb);
1537 * If already streaming, give the buffer to driver for processing.
1538 * If not, the buffer will be given to driver on next streamon.
1540 if (q->start_streaming_called)
1541 __enqueue_in_driver(vb);
1543 /* Fill buffer information for the userspace */
1545 call_void_bufop(q, fill_user_buffer, vb, pb);
1548 * If streamon has been called, and we haven't yet called
1549 * start_streaming() since not enough buffers were queued, and
1550 * we now have reached the minimum number of queued buffers,
1551 * then we can finally call start_streaming().
1553 if (q->streaming && !q->start_streaming_called &&
1554 q->queued_count >= q->min_buffers_needed) {
1555 ret = vb2_start_streaming(q);
1560 dprintk(1, "qbuf of buffer %d succeeded\n", vb->index);
1563 EXPORT_SYMBOL_GPL(vb2_core_qbuf);
1566 * __vb2_wait_for_done_vb() - wait for a buffer to become available
1569 * Will sleep if required for nonblocking == false.
1571 static int __vb2_wait_for_done_vb(struct vb2_queue *q, int nonblocking)
1574 * All operations on vb_done_list are performed under done_lock
1575 * spinlock protection. However, buffers may be removed from
1576 * it and returned to userspace only while holding both driver's
1577 * lock and the done_lock spinlock. Thus we can be sure that as
1578 * long as we hold the driver's lock, the list will remain not
1579 * empty if list_empty() check succeeds.
1585 if (!q->streaming) {
1586 dprintk(1, "streaming off, will not wait for buffers\n");
1591 dprintk(1, "Queue in error state, will not wait for buffers\n");
1595 if (q->last_buffer_dequeued) {
1596 dprintk(3, "last buffer dequeued already, will not wait for buffers\n");
1600 if (!list_empty(&q->done_list)) {
1602 * Found a buffer that we were waiting for.
1608 dprintk(1, "nonblocking and no buffers to dequeue, "
1614 * We are streaming and blocking, wait for another buffer to
1615 * become ready or for streamoff. Driver's lock is released to
1616 * allow streamoff or qbuf to be called while waiting.
1618 call_void_qop(q, wait_prepare, q);
1621 * All locks have been released, it is safe to sleep now.
1623 dprintk(3, "will sleep waiting for buffers\n");
1624 ret = wait_event_interruptible(q->done_wq,
1625 !list_empty(&q->done_list) || !q->streaming ||
1629 * We need to reevaluate both conditions again after reacquiring
1630 * the locks or return an error if one occurred.
1632 call_void_qop(q, wait_finish, q);
1634 dprintk(1, "sleep was interrupted\n");
1642 * __vb2_get_done_vb() - get a buffer ready for dequeuing
1644 * Will sleep if required for nonblocking == false.
1646 static int __vb2_get_done_vb(struct vb2_queue *q, struct vb2_buffer **vb,
1649 unsigned long flags;
1653 * Wait for at least one buffer to become available on the done_list.
1655 ret = __vb2_wait_for_done_vb(q, nonblocking);
1660 * Driver's lock has been held since we last verified that done_list
1661 * is not empty, so no need for another list_empty(done_list) check.
1663 spin_lock_irqsave(&q->done_lock, flags);
1664 *vb = list_first_entry(&q->done_list, struct vb2_buffer, done_entry);
1666 * Only remove the buffer from done_list if v4l2_buffer can handle all
1668 * Verifying planes is NOT necessary since it already has been checked
1669 * before the buffer is queued/prepared. So it can never fail.
1671 list_del(&(*vb)->done_entry);
1672 spin_unlock_irqrestore(&q->done_lock, flags);
1678 * vb2_wait_for_all_buffers() - wait until all buffers are given back to vb2
1679 * @q: videobuf2 queue
1681 * This function will wait until all buffers that have been given to the driver
1682 * by buf_queue() are given back to vb2 with vb2_buffer_done(). It doesn't call
1683 * wait_prepare, wait_finish pair. It is intended to be called with all locks
1684 * taken, for example from stop_streaming() callback.
1686 int vb2_wait_for_all_buffers(struct vb2_queue *q)
1688 if (!q->streaming) {
1689 dprintk(1, "streaming off, will not wait for buffers\n");
1693 if (q->start_streaming_called)
1694 wait_event(q->done_wq, !atomic_read(&q->owned_by_drv_count));
1697 EXPORT_SYMBOL_GPL(vb2_wait_for_all_buffers);
1700 * __vb2_dqbuf() - bring back the buffer to the DEQUEUED state
1702 static void __vb2_dqbuf(struct vb2_buffer *vb)
1704 struct vb2_queue *q = vb->vb2_queue;
1707 /* nothing to do if the buffer is already dequeued */
1708 if (vb->state == VB2_BUF_STATE_DEQUEUED)
1711 vb->state = VB2_BUF_STATE_DEQUEUED;
1713 /* unmap DMABUF buffer */
1714 if (q->memory == VB2_MEMORY_DMABUF)
1715 for (i = 0; i < vb->num_planes; ++i) {
1716 if (!vb->planes[i].dbuf_mapped)
1718 call_void_memop(vb, unmap_dmabuf, vb->planes[i].mem_priv);
1719 vb->planes[i].dbuf_mapped = 0;
1724 * vb2_dqbuf() - Dequeue a buffer to the userspace
1725 * @q: videobuf2 queue
1726 * @pb: buffer structure passed from userspace to vidioc_dqbuf handler
1728 * @nonblocking: if true, this call will not sleep waiting for a buffer if no
1729 * buffers ready for dequeuing are present. Normally the driver
1730 * would be passing (file->f_flags & O_NONBLOCK) here
1732 * Should be called from vidioc_dqbuf ioctl handler of a driver.
1733 * The passed buffer should have been verified.
1735 * 1) calls buf_finish callback in the driver (if provided), in which
1736 * driver can perform any additional operations that may be required before
1737 * returning the buffer to userspace, such as cache sync,
1738 * 2) the buffer struct members are filled with relevant information for
1741 * The return values from this function are intended to be directly returned
1742 * from vidioc_dqbuf handler in driver.
1744 int vb2_core_dqbuf(struct vb2_queue *q, unsigned int *pindex, void *pb,
1747 struct vb2_buffer *vb = NULL;
1750 ret = __vb2_get_done_vb(q, &vb, nonblocking);
1754 switch (vb->state) {
1755 case VB2_BUF_STATE_DONE:
1756 dprintk(3, "returning done buffer\n");
1758 case VB2_BUF_STATE_ERROR:
1759 dprintk(3, "returning done buffer with errors\n");
1762 dprintk(1, "invalid buffer state\n");
1766 call_void_vb_qop(vb, buf_finish, vb);
1769 *pindex = vb->index;
1771 /* Fill buffer information for the userspace */
1773 call_void_bufop(q, fill_user_buffer, vb, pb);
1775 /* Remove from videobuf queue */
1776 list_del(&vb->queued_entry);
1779 trace_vb2_dqbuf(q, vb);
1781 /* go back to dequeued state */
1784 dprintk(1, "dqbuf of buffer %d, with state %d\n",
1785 vb->index, vb->state);
1790 EXPORT_SYMBOL_GPL(vb2_core_dqbuf);
1793 * __vb2_queue_cancel() - cancel and stop (pause) streaming
1795 * Removes all queued buffers from driver's queue and all buffers queued by
1796 * userspace from videobuf's queue. Returns to state after reqbufs.
1798 static void __vb2_queue_cancel(struct vb2_queue *q)
1803 * Tell driver to stop all transactions and release all queued
1806 if (q->start_streaming_called)
1807 call_void_qop(q, stop_streaming, q);
1810 * If you see this warning, then the driver isn't cleaning up properly
1811 * in stop_streaming(). See the stop_streaming() documentation in
1812 * videobuf2-core.h for more information how buffers should be returned
1813 * to vb2 in stop_streaming().
1815 if (WARN_ON(atomic_read(&q->owned_by_drv_count))) {
1816 for (i = 0; i < q->num_buffers; ++i)
1817 if (q->bufs[i]->state == VB2_BUF_STATE_ACTIVE)
1818 vb2_buffer_done(q->bufs[i], VB2_BUF_STATE_ERROR);
1819 /* Must be zero now */
1820 WARN_ON(atomic_read(&q->owned_by_drv_count));
1824 q->start_streaming_called = 0;
1825 q->queued_count = 0;
1829 * Remove all buffers from videobuf's list...
1831 INIT_LIST_HEAD(&q->queued_list);
1833 * ...and done list; userspace will not receive any buffers it
1834 * has not already dequeued before initiating cancel.
1836 INIT_LIST_HEAD(&q->done_list);
1837 atomic_set(&q->owned_by_drv_count, 0);
1838 wake_up_all(&q->done_wq);
1841 * Reinitialize all buffers for next use.
1842 * Make sure to call buf_finish for any queued buffers. Normally
1843 * that's done in dqbuf, but that's not going to happen when we
1844 * cancel the whole queue. Note: this code belongs here, not in
1845 * __vb2_dqbuf() since in vb2_internal_dqbuf() there is a critical
1846 * call to __fill_user_buffer() after buf_finish(). That order can't
1847 * be changed, so we can't move the buf_finish() to __vb2_dqbuf().
1849 for (i = 0; i < q->num_buffers; ++i) {
1850 struct vb2_buffer *vb = q->bufs[i];
1852 if (vb->state != VB2_BUF_STATE_DEQUEUED) {
1853 vb->state = VB2_BUF_STATE_PREPARED;
1854 call_void_vb_qop(vb, buf_finish, vb);
1860 int vb2_core_streamon(struct vb2_queue *q, unsigned int type)
1864 if (type != q->type) {
1865 dprintk(1, "invalid stream type\n");
1870 dprintk(3, "already streaming\n");
1874 if (!q->num_buffers) {
1875 dprintk(1, "no buffers have been allocated\n");
1879 if (q->num_buffers < q->min_buffers_needed) {
1880 dprintk(1, "need at least %u allocated buffers\n",
1881 q->min_buffers_needed);
1886 * Tell driver to start streaming provided sufficient buffers
1889 if (q->queued_count >= q->min_buffers_needed) {
1890 ret = vb2_start_streaming(q);
1892 __vb2_queue_cancel(q);
1899 dprintk(3, "successful\n");
1902 EXPORT_SYMBOL_GPL(vb2_core_streamon);
1905 * vb2_queue_error() - signal a fatal error on the queue
1906 * @q: videobuf2 queue
1908 * Flag that a fatal unrecoverable error has occurred and wake up all processes
1909 * waiting on the queue. Polling will now set POLLERR and queuing and dequeuing
1910 * buffers will return -EIO.
1912 * The error flag will be cleared when cancelling the queue, either from
1913 * vb2_streamoff or vb2_queue_release. Drivers should thus not call this
1914 * function before starting the stream, otherwise the error flag will remain set
1915 * until the queue is released when closing the device node.
1917 void vb2_queue_error(struct vb2_queue *q)
1921 wake_up_all(&q->done_wq);
1923 EXPORT_SYMBOL_GPL(vb2_queue_error);
1925 int vb2_core_streamoff(struct vb2_queue *q, unsigned int type)
1927 if (type != q->type) {
1928 dprintk(1, "invalid stream type\n");
1933 * Cancel will pause streaming and remove all buffers from the driver
1934 * and videobuf, effectively returning control over them to userspace.
1936 * Note that we do this even if q->streaming == 0: if you prepare or
1937 * queue buffers, and then call streamoff without ever having called
1938 * streamon, you would still expect those buffers to be returned to
1939 * their normal dequeued state.
1941 __vb2_queue_cancel(q);
1942 q->waiting_for_buffers = !q->is_output;
1943 q->last_buffer_dequeued = false;
1945 dprintk(3, "successful\n");
1948 EXPORT_SYMBOL_GPL(vb2_core_streamoff);
1951 * __find_plane_by_offset() - find plane associated with the given offset off
1953 static int __find_plane_by_offset(struct vb2_queue *q, unsigned long off,
1954 unsigned int *_buffer, unsigned int *_plane)
1956 struct vb2_buffer *vb;
1957 unsigned int buffer, plane;
1960 * Go over all buffers and their planes, comparing the given offset
1961 * with an offset assigned to each plane. If a match is found,
1962 * return its buffer and plane numbers.
1964 for (buffer = 0; buffer < q->num_buffers; ++buffer) {
1965 vb = q->bufs[buffer];
1967 for (plane = 0; plane < vb->num_planes; ++plane) {
1968 if (vb->planes[plane].m.offset == off) {
1980 * vb2_core_expbuf() - Export a buffer as a file descriptor
1981 * @q: videobuf2 queue
1982 * @fd: file descriptor associated with DMABUF (set by driver) *
1983 * @type: buffer type
1984 * @index: id number of the buffer
1985 * @plane: index of the plane to be exported, 0 for single plane queues
1986 * @flags: flags for newly created file, currently only O_CLOEXEC is
1987 * supported, refer to manual of open syscall for more details
1989 * The return values from this function are intended to be directly returned
1990 * from vidioc_expbuf handler in driver.
1992 int vb2_core_expbuf(struct vb2_queue *q, int *fd, unsigned int type,
1993 unsigned int index, unsigned int plane, unsigned int flags)
1995 struct vb2_buffer *vb = NULL;
1996 struct vb2_plane *vb_plane;
1998 struct dma_buf *dbuf;
2000 if (q->memory != VB2_MEMORY_MMAP) {
2001 dprintk(1, "queue is not currently set up for mmap\n");
2005 if (!q->mem_ops->get_dmabuf) {
2006 dprintk(1, "queue does not support DMA buffer exporting\n");
2010 if (flags & ~(O_CLOEXEC | O_ACCMODE)) {
2011 dprintk(1, "queue does support only O_CLOEXEC and access mode flags\n");
2015 if (type != q->type) {
2016 dprintk(1, "invalid buffer type\n");
2020 if (index >= q->num_buffers) {
2021 dprintk(1, "buffer index out of range\n");
2025 vb = q->bufs[index];
2027 if (plane >= vb->num_planes) {
2028 dprintk(1, "buffer plane out of range\n");
2032 if (vb2_fileio_is_active(q)) {
2033 dprintk(1, "expbuf: file io in progress\n");
2037 vb_plane = &vb->planes[plane];
2039 dbuf = call_ptr_memop(vb, get_dmabuf, vb_plane->mem_priv,
2041 if (IS_ERR_OR_NULL(dbuf)) {
2042 dprintk(1, "failed to export buffer %d, plane %d\n",
2047 ret = dma_buf_fd(dbuf, flags & ~O_ACCMODE);
2049 dprintk(3, "buffer %d, plane %d failed to export (%d)\n",
2055 dprintk(3, "buffer %d, plane %d exported as %d descriptor\n",
2061 EXPORT_SYMBOL_GPL(vb2_core_expbuf);
2064 * vb2_mmap() - map video buffers into application address space
2065 * @q: videobuf2 queue
2066 * @vma: vma passed to the mmap file operation handler in the driver
2068 * Should be called from mmap file operation handler of a driver.
2069 * This function maps one plane of one of the available video buffers to
2070 * userspace. To map whole video memory allocated on reqbufs, this function
2071 * has to be called once per each plane per each buffer previously allocated.
2073 * When the userspace application calls mmap, it passes to it an offset returned
2074 * to it earlier by the means of vidioc_querybuf handler. That offset acts as
2075 * a "cookie", which is then used to identify the plane to be mapped.
2076 * This function finds a plane with a matching offset and a mapping is performed
2077 * by the means of a provided memory operation.
2079 * The return values from this function are intended to be directly returned
2080 * from the mmap handler in driver.
2082 int vb2_mmap(struct vb2_queue *q, struct vm_area_struct *vma)
2084 unsigned long off = vma->vm_pgoff << PAGE_SHIFT;
2085 struct vb2_buffer *vb;
2086 unsigned int buffer = 0, plane = 0;
2088 unsigned long length;
2090 if (q->memory != VB2_MEMORY_MMAP) {
2091 dprintk(1, "queue is not currently set up for mmap\n");
2096 * Check memory area access mode.
2098 if (!(vma->vm_flags & VM_SHARED)) {
2099 dprintk(1, "invalid vma flags, VM_SHARED needed\n");
2103 if (!(vma->vm_flags & VM_WRITE)) {
2104 dprintk(1, "invalid vma flags, VM_WRITE needed\n");
2108 if (!(vma->vm_flags & VM_READ)) {
2109 dprintk(1, "invalid vma flags, VM_READ needed\n");
2113 if (vb2_fileio_is_active(q)) {
2114 dprintk(1, "mmap: file io in progress\n");
2119 * Find the plane corresponding to the offset passed by userspace.
2121 ret = __find_plane_by_offset(q, off, &buffer, &plane);
2125 vb = q->bufs[buffer];
2128 * MMAP requires page_aligned buffers.
2129 * The buffer length was page_aligned at __vb2_buf_mem_alloc(),
2130 * so, we need to do the same here.
2132 length = PAGE_ALIGN(vb->planes[plane].length);
2133 if (length < (vma->vm_end - vma->vm_start)) {
2135 "MMAP invalid, as it would overflow buffer length\n");
2139 mutex_lock(&q->mmap_lock);
2140 ret = call_memop(vb, mmap, vb->planes[plane].mem_priv, vma);
2141 mutex_unlock(&q->mmap_lock);
2145 dprintk(3, "buffer %d, plane %d successfully mapped\n", buffer, plane);
2148 EXPORT_SYMBOL_GPL(vb2_mmap);
2151 unsigned long vb2_get_unmapped_area(struct vb2_queue *q,
2154 unsigned long pgoff,
2155 unsigned long flags)
2157 unsigned long off = pgoff << PAGE_SHIFT;
2158 struct vb2_buffer *vb;
2159 unsigned int buffer, plane;
2163 if (q->memory != VB2_MEMORY_MMAP) {
2164 dprintk(1, "queue is not currently set up for mmap\n");
2169 * Find the plane corresponding to the offset passed by userspace.
2171 ret = __find_plane_by_offset(q, off, &buffer, &plane);
2175 vb = q->bufs[buffer];
2177 vaddr = vb2_plane_vaddr(vb, plane);
2178 return vaddr ? (unsigned long)vaddr : -EINVAL;
2180 EXPORT_SYMBOL_GPL(vb2_get_unmapped_area);
2184 * vb2_core_queue_init() - initialize a videobuf2 queue
2185 * @q: videobuf2 queue; this structure should be allocated in driver
2187 * The vb2_queue structure should be allocated by the driver. The driver is
2188 * responsible of clearing it's content and setting initial values for some
2189 * required entries before calling this function.
2190 * q->ops, q->mem_ops, q->type and q->io_modes are mandatory. Please refer
2191 * to the struct vb2_queue description in include/media/videobuf2-core.h
2192 * for more information.
2194 int vb2_core_queue_init(struct vb2_queue *q)
2201 WARN_ON(!q->mem_ops) ||
2202 WARN_ON(!q->type) ||
2203 WARN_ON(!q->io_modes) ||
2204 WARN_ON(!q->ops->queue_setup) ||
2205 WARN_ON(!q->ops->buf_queue))
2208 INIT_LIST_HEAD(&q->queued_list);
2209 INIT_LIST_HEAD(&q->done_list);
2210 spin_lock_init(&q->done_lock);
2211 mutex_init(&q->mmap_lock);
2212 init_waitqueue_head(&q->done_wq);
2214 if (q->buf_struct_size == 0)
2215 q->buf_struct_size = sizeof(struct vb2_buffer);
2219 EXPORT_SYMBOL_GPL(vb2_core_queue_init);
2221 static int __vb2_init_fileio(struct vb2_queue *q, int read);
2222 static int __vb2_cleanup_fileio(struct vb2_queue *q);
2224 * vb2_core_queue_release() - stop streaming, release the queue and free memory
2225 * @q: videobuf2 queue
2227 * This function stops streaming and performs necessary clean ups, including
2228 * freeing video buffer memory. The driver is responsible for freeing
2229 * the vb2_queue structure itself.
2231 void vb2_core_queue_release(struct vb2_queue *q)
2233 __vb2_cleanup_fileio(q);
2234 __vb2_queue_cancel(q);
2235 mutex_lock(&q->mmap_lock);
2236 __vb2_queue_free(q, q->num_buffers);
2237 mutex_unlock(&q->mmap_lock);
2239 EXPORT_SYMBOL_GPL(vb2_core_queue_release);
2242 * vb2_core_poll() - implements poll userspace operation
2243 * @q: videobuf2 queue
2244 * @file: file argument passed to the poll file operation handler
2245 * @wait: wait argument passed to the poll file operation handler
2247 * This function implements poll file operation handler for a driver.
2248 * For CAPTURE queues, if a buffer is ready to be dequeued, the userspace will
2249 * be informed that the file descriptor of a video device is available for
2251 * For OUTPUT queues, if a buffer is ready to be dequeued, the file descriptor
2252 * will be reported as available for writing.
2254 * The return values from this function are intended to be directly returned
2255 * from poll handler in driver.
2257 unsigned int vb2_core_poll(struct vb2_queue *q, struct file *file,
2260 unsigned long req_events = poll_requested_events(wait);
2261 struct vb2_buffer *vb = NULL;
2262 unsigned long flags;
2264 if (!q->is_output && !(req_events & (POLLIN | POLLRDNORM)))
2266 if (q->is_output && !(req_events & (POLLOUT | POLLWRNORM)))
2270 * Start file I/O emulator only if streaming API has not been used yet.
2272 if (q->num_buffers == 0 && !vb2_fileio_is_active(q)) {
2273 if (!q->is_output && (q->io_modes & VB2_READ) &&
2274 (req_events & (POLLIN | POLLRDNORM))) {
2275 if (__vb2_init_fileio(q, 1))
2278 if (q->is_output && (q->io_modes & VB2_WRITE) &&
2279 (req_events & (POLLOUT | POLLWRNORM))) {
2280 if (__vb2_init_fileio(q, 0))
2283 * Write to OUTPUT queue can be done immediately.
2285 return POLLOUT | POLLWRNORM;
2290 * There is nothing to wait for if the queue isn't streaming, or if the
2291 * error flag is set.
2293 if (!vb2_is_streaming(q) || q->error)
2297 * For output streams you can call write() as long as there are fewer
2298 * buffers queued than there are buffers available.
2300 if (q->is_output && q->fileio && q->queued_count < q->num_buffers)
2301 return POLLOUT | POLLWRNORM;
2303 if (list_empty(&q->done_list)) {
2305 * If the last buffer was dequeued from a capture queue,
2306 * return immediately. DQBUF will return -EPIPE.
2308 if (q->last_buffer_dequeued)
2309 return POLLIN | POLLRDNORM;
2311 poll_wait(file, &q->done_wq, wait);
2315 * Take first buffer available for dequeuing.
2317 spin_lock_irqsave(&q->done_lock, flags);
2318 if (!list_empty(&q->done_list))
2319 vb = list_first_entry(&q->done_list, struct vb2_buffer,
2321 spin_unlock_irqrestore(&q->done_lock, flags);
2323 if (vb && (vb->state == VB2_BUF_STATE_DONE
2324 || vb->state == VB2_BUF_STATE_ERROR)) {
2325 return (q->is_output) ?
2326 POLLOUT | POLLWRNORM :
2327 POLLIN | POLLRDNORM;
2331 EXPORT_SYMBOL_GPL(vb2_core_poll);
2334 * struct vb2_fileio_buf - buffer context used by file io emulator
2336 * vb2 provides a compatibility layer and emulator of file io (read and
2337 * write) calls on top of streaming API. This structure is used for
2338 * tracking context related to the buffers.
2340 struct vb2_fileio_buf {
2344 unsigned int queued:1;
2348 * struct vb2_fileio_data - queue context used by file io emulator
2350 * @cur_index: the index of the buffer currently being read from or
2351 * written to. If equal to q->num_buffers then a new buffer
2353 * @initial_index: in the read() case all buffers are queued up immediately
2354 * in __vb2_init_fileio() and __vb2_perform_fileio() just cycles
2355 * buffers. However, in the write() case no buffers are initially
2356 * queued, instead whenever a buffer is full it is queued up by
2357 * __vb2_perform_fileio(). Only once all available buffers have
2358 * been queued up will __vb2_perform_fileio() start to dequeue
2359 * buffers. This means that initially __vb2_perform_fileio()
2360 * needs to know what buffer index to use when it is queuing up
2361 * the buffers for the first time. That initial index is stored
2362 * in this field. Once it is equal to q->num_buffers all
2363 * available buffers have been queued and __vb2_perform_fileio()
2364 * should start the normal dequeue/queue cycle.
2366 * vb2 provides a compatibility layer and emulator of file io (read and
2367 * write) calls on top of streaming API. For proper operation it required
2368 * this structure to save the driver state between each call of the read
2369 * or write function.
2371 struct vb2_fileio_data {
2374 unsigned int memory;
2375 struct vb2_fileio_buf bufs[VB2_MAX_FRAME];
2376 unsigned int cur_index;
2377 unsigned int initial_index;
2378 unsigned int q_count;
2379 unsigned int dq_count;
2380 unsigned read_once:1;
2381 unsigned write_immediately:1;
2385 * __vb2_init_fileio() - initialize file io emulator
2386 * @q: videobuf2 queue
2387 * @read: mode selector (1 means read, 0 means write)
2389 static int __vb2_init_fileio(struct vb2_queue *q, int read)
2391 struct vb2_fileio_data *fileio;
2393 unsigned int count = 0;
2398 if (WARN_ON((read && !(q->io_modes & VB2_READ)) ||
2399 (!read && !(q->io_modes & VB2_WRITE))))
2403 * Check if device supports mapping buffers to kernel virtual space.
2405 if (!q->mem_ops->vaddr)
2409 * Check if streaming api has not been already activated.
2411 if (q->streaming || q->num_buffers > 0)
2415 * Start with count 1, driver can increase it in queue_setup()
2419 dprintk(3, "setting up file io: mode %s, count %d, read_once %d, write_immediately %d\n",
2420 (read) ? "read" : "write", count, q->fileio_read_once,
2421 q->fileio_write_immediately);
2423 fileio = kzalloc(sizeof(*fileio), GFP_KERNEL);
2427 fileio->read_once = q->fileio_read_once;
2428 fileio->write_immediately = q->fileio_write_immediately;
2431 * Request buffers and use MMAP type to force driver
2432 * to allocate buffers by itself.
2434 fileio->count = count;
2435 fileio->memory = VB2_MEMORY_MMAP;
2436 fileio->type = q->type;
2438 ret = vb2_core_reqbufs(q, fileio->memory, &fileio->count);
2443 * Check if plane_count is correct
2444 * (multiplane buffers are not supported).
2446 if (q->bufs[0]->num_planes != 1) {
2452 * Get kernel address of each buffer.
2454 for (i = 0; i < q->num_buffers; i++) {
2455 fileio->bufs[i].vaddr = vb2_plane_vaddr(q->bufs[i], 0);
2456 if (fileio->bufs[i].vaddr == NULL) {
2460 fileio->bufs[i].size = vb2_plane_size(q->bufs[i], 0);
2464 * Read mode requires pre queuing of all buffers.
2468 * Queue all buffers.
2470 for (i = 0; i < q->num_buffers; i++) {
2471 ret = vb2_core_qbuf(q, i, NULL);
2474 fileio->bufs[i].queued = 1;
2477 * All buffers have been queued, so mark that by setting
2478 * initial_index to q->num_buffers
2480 fileio->initial_index = q->num_buffers;
2481 fileio->cur_index = q->num_buffers;
2487 ret = vb2_core_streamon(q, q->type);
2495 vb2_core_reqbufs(q, fileio->memory, &fileio->count);
2504 * __vb2_cleanup_fileio() - free resourced used by file io emulator
2505 * @q: videobuf2 queue
2507 static int __vb2_cleanup_fileio(struct vb2_queue *q)
2509 struct vb2_fileio_data *fileio = q->fileio;
2512 vb2_core_streamoff(q, q->type);
2515 vb2_core_reqbufs(q, fileio->memory, &fileio->count);
2517 dprintk(3, "file io emulator closed\n");
2523 * __vb2_perform_fileio() - perform a single file io (read or write) operation
2524 * @q: videobuf2 queue
2525 * @data: pointed to target userspace buffer
2526 * @count: number of bytes to read or write
2527 * @ppos: file handle position tracking pointer
2528 * @nonblock: mode selector (1 means blocking calls, 0 means nonblocking)
2529 * @read: access mode selector (1 means read, 0 means write)
2531 static size_t __vb2_perform_fileio(struct vb2_queue *q, char __user *data, size_t count,
2532 loff_t *ppos, int nonblock, int read)
2534 struct vb2_fileio_data *fileio;
2535 struct vb2_fileio_buf *buf;
2536 bool is_multiplanar = q->is_multiplanar;
2538 * When using write() to write data to an output video node the vb2 core
2539 * should copy timestamps if V4L2_BUF_FLAG_TIMESTAMP_COPY is set. Nobody
2540 * else is able to provide this information with the write() operation.
2542 bool copy_timestamp = !read && q->copy_timestamp;
2546 dprintk(3, "mode %s, offset %ld, count %zd, %sblocking\n",
2547 read ? "read" : "write", (long)*ppos, count,
2548 nonblock ? "non" : "");
2554 * Initialize emulator on first call.
2556 if (!vb2_fileio_is_active(q)) {
2557 ret = __vb2_init_fileio(q, read);
2558 dprintk(3, "vb2_init_fileio result: %d\n", ret);
2565 * Check if we need to dequeue the buffer.
2567 index = fileio->cur_index;
2568 if (index >= q->num_buffers) {
2569 struct vb2_buffer *b;
2572 * Call vb2_dqbuf to get buffer back.
2574 ret = vb2_core_dqbuf(q, &index, NULL, nonblock);
2575 dprintk(5, "vb2_dqbuf result: %d\n", ret);
2578 fileio->dq_count += 1;
2580 fileio->cur_index = index;
2581 buf = &fileio->bufs[index];
2585 * Get number of bytes filled by the driver
2589 buf->size = read ? vb2_get_plane_payload(q->bufs[index], 0)
2590 : vb2_plane_size(q->bufs[index], 0);
2591 /* Compensate for data_offset on read in the multiplanar case. */
2592 if (is_multiplanar && read &&
2593 b->planes[0].data_offset < buf->size) {
2594 buf->pos = b->planes[0].data_offset;
2595 buf->size -= buf->pos;
2598 buf = &fileio->bufs[index];
2602 * Limit count on last few bytes of the buffer.
2604 if (buf->pos + count > buf->size) {
2605 count = buf->size - buf->pos;
2606 dprintk(5, "reducing read count: %zd\n", count);
2610 * Transfer data to userspace.
2612 dprintk(3, "copying %zd bytes - buffer %d, offset %u\n",
2613 count, index, buf->pos);
2615 ret = copy_to_user(data, buf->vaddr + buf->pos, count);
2617 ret = copy_from_user(buf->vaddr + buf->pos, data, count);
2619 dprintk(3, "error copying data\n");
2630 * Queue next buffer if required.
2632 if (buf->pos == buf->size || (!read && fileio->write_immediately)) {
2633 struct vb2_buffer *b = q->bufs[index];
2636 * Check if this is the last buffer to read.
2638 if (read && fileio->read_once && fileio->dq_count == 1) {
2639 dprintk(3, "read limit reached\n");
2640 return __vb2_cleanup_fileio(q);
2644 * Call vb2_qbuf and give buffer to the driver.
2646 b->planes[0].bytesused = buf->pos;
2649 b->timestamp = ktime_get_ns();
2650 ret = vb2_core_qbuf(q, index, NULL);
2651 dprintk(5, "vb2_dbuf result: %d\n", ret);
2656 * Buffer has been queued, update the status
2660 buf->size = vb2_plane_size(q->bufs[index], 0);
2661 fileio->q_count += 1;
2663 * If we are queuing up buffers for the first time, then
2664 * increase initial_index by one.
2666 if (fileio->initial_index < q->num_buffers)
2667 fileio->initial_index++;
2669 * The next buffer to use is either a buffer that's going to be
2670 * queued for the first time (initial_index < q->num_buffers)
2671 * or it is equal to q->num_buffers, meaning that the next
2672 * time we need to dequeue a buffer since we've now queued up
2673 * all the 'first time' buffers.
2675 fileio->cur_index = fileio->initial_index;
2679 * Return proper number of bytes processed.
2686 size_t vb2_read(struct vb2_queue *q, char __user *data, size_t count,
2687 loff_t *ppos, int nonblocking)
2689 return __vb2_perform_fileio(q, data, count, ppos, nonblocking, 1);
2691 EXPORT_SYMBOL_GPL(vb2_read);
2693 size_t vb2_write(struct vb2_queue *q, const char __user *data, size_t count,
2694 loff_t *ppos, int nonblocking)
2696 return __vb2_perform_fileio(q, (char __user *) data, count,
2697 ppos, nonblocking, 0);
2699 EXPORT_SYMBOL_GPL(vb2_write);
2701 struct vb2_threadio_data {
2702 struct task_struct *thread;
2708 static int vb2_thread(void *data)
2710 struct vb2_queue *q = data;
2711 struct vb2_threadio_data *threadio = q->threadio;
2712 bool copy_timestamp = false;
2713 unsigned prequeue = 0;
2718 prequeue = q->num_buffers;
2719 copy_timestamp = q->copy_timestamp;
2725 struct vb2_buffer *vb;
2728 * Call vb2_dqbuf to get buffer back.
2731 vb = q->bufs[index++];
2734 call_void_qop(q, wait_finish, q);
2735 if (!threadio->stop)
2736 ret = vb2_core_dqbuf(q, &index, NULL, 0);
2737 call_void_qop(q, wait_prepare, q);
2738 dprintk(5, "file io: vb2_dqbuf result: %d\n", ret);
2740 vb = q->bufs[index];
2742 if (ret || threadio->stop)
2746 if (vb->state != VB2_BUF_STATE_ERROR)
2747 if (threadio->fnc(vb, threadio->priv))
2749 call_void_qop(q, wait_finish, q);
2751 vb->timestamp = ktime_get_ns();;
2752 if (!threadio->stop)
2753 ret = vb2_core_qbuf(q, vb->index, NULL);
2754 call_void_qop(q, wait_prepare, q);
2755 if (ret || threadio->stop)
2759 /* Hmm, linux becomes *very* unhappy without this ... */
2760 while (!kthread_should_stop()) {
2761 set_current_state(TASK_INTERRUPTIBLE);
2768 * This function should not be used for anything else but the videobuf2-dvb
2769 * support. If you think you have another good use-case for this, then please
2770 * contact the linux-media mailinglist first.
2772 int vb2_thread_start(struct vb2_queue *q, vb2_thread_fnc fnc, void *priv,
2773 const char *thread_name)
2775 struct vb2_threadio_data *threadio;
2782 if (WARN_ON(q->fileio))
2785 threadio = kzalloc(sizeof(*threadio), GFP_KERNEL);
2786 if (threadio == NULL)
2788 threadio->fnc = fnc;
2789 threadio->priv = priv;
2791 ret = __vb2_init_fileio(q, !q->is_output);
2792 dprintk(3, "file io: vb2_init_fileio result: %d\n", ret);
2795 q->threadio = threadio;
2796 threadio->thread = kthread_run(vb2_thread, q, "vb2-%s", thread_name);
2797 if (IS_ERR(threadio->thread)) {
2798 ret = PTR_ERR(threadio->thread);
2799 threadio->thread = NULL;
2805 __vb2_cleanup_fileio(q);
2810 EXPORT_SYMBOL_GPL(vb2_thread_start);
2812 int vb2_thread_stop(struct vb2_queue *q)
2814 struct vb2_threadio_data *threadio = q->threadio;
2817 if (threadio == NULL)
2819 threadio->stop = true;
2820 /* Wake up all pending sleeps in the thread */
2822 err = kthread_stop(threadio->thread);
2823 __vb2_cleanup_fileio(q);
2824 threadio->thread = NULL;
2829 EXPORT_SYMBOL_GPL(vb2_thread_stop);
2831 MODULE_DESCRIPTION("Media buffer core framework");
2832 MODULE_AUTHOR("Pawel Osciak <pawel@osciak.com>, Marek Szyprowski");
2833 MODULE_LICENSE("GPL");