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>
28 #include <media/v4l2-mc.h>
30 #include <trace/events/vb2.h>
33 module_param(debug, int, 0644);
35 #define dprintk(level, fmt, arg...) \
38 pr_info("vb2-core: %s: " fmt, __func__, ## arg); \
41 #ifdef CONFIG_VIDEO_ADV_DEBUG
44 * If advanced debugging is on, then count how often each op is called
45 * successfully, which can either be per-buffer or per-queue.
47 * This makes it easy to check that the 'init' and 'cleanup'
48 * (and variations thereof) stay balanced.
51 #define log_memop(vb, op) \
52 dprintk(2, "call_memop(%p, %d, %s)%s\n", \
53 (vb)->vb2_queue, (vb)->index, #op, \
54 (vb)->vb2_queue->mem_ops->op ? "" : " (nop)")
56 #define call_memop(vb, op, args...) \
58 struct vb2_queue *_q = (vb)->vb2_queue; \
62 err = _q->mem_ops->op ? _q->mem_ops->op(args) : 0; \
64 (vb)->cnt_mem_ ## op++; \
68 #define call_ptr_memop(vb, op, args...) \
70 struct vb2_queue *_q = (vb)->vb2_queue; \
74 ptr = _q->mem_ops->op ? _q->mem_ops->op(args) : NULL; \
75 if (!IS_ERR_OR_NULL(ptr)) \
76 (vb)->cnt_mem_ ## op++; \
80 #define call_void_memop(vb, op, args...) \
82 struct vb2_queue *_q = (vb)->vb2_queue; \
85 if (_q->mem_ops->op) \
86 _q->mem_ops->op(args); \
87 (vb)->cnt_mem_ ## op++; \
90 #define log_qop(q, op) \
91 dprintk(2, "call_qop(%p, %s)%s\n", q, #op, \
92 (q)->ops->op ? "" : " (nop)")
94 #define call_qop(q, op, args...) \
99 err = (q)->ops->op ? (q)->ops->op(args) : 0; \
105 #define call_void_qop(q, op, args...) \
109 (q)->ops->op(args); \
113 #define log_vb_qop(vb, op, args...) \
114 dprintk(2, "call_vb_qop(%p, %d, %s)%s\n", \
115 (vb)->vb2_queue, (vb)->index, #op, \
116 (vb)->vb2_queue->ops->op ? "" : " (nop)")
118 #define call_vb_qop(vb, op, args...) \
122 log_vb_qop(vb, op); \
123 err = (vb)->vb2_queue->ops->op ? \
124 (vb)->vb2_queue->ops->op(args) : 0; \
126 (vb)->cnt_ ## op++; \
130 #define call_void_vb_qop(vb, op, args...) \
132 log_vb_qop(vb, op); \
133 if ((vb)->vb2_queue->ops->op) \
134 (vb)->vb2_queue->ops->op(args); \
135 (vb)->cnt_ ## op++; \
140 #define call_memop(vb, op, args...) \
141 ((vb)->vb2_queue->mem_ops->op ? \
142 (vb)->vb2_queue->mem_ops->op(args) : 0)
144 #define call_ptr_memop(vb, op, args...) \
145 ((vb)->vb2_queue->mem_ops->op ? \
146 (vb)->vb2_queue->mem_ops->op(args) : NULL)
148 #define call_void_memop(vb, op, args...) \
150 if ((vb)->vb2_queue->mem_ops->op) \
151 (vb)->vb2_queue->mem_ops->op(args); \
154 #define call_qop(q, op, args...) \
155 ((q)->ops->op ? (q)->ops->op(args) : 0)
157 #define call_void_qop(q, op, args...) \
160 (q)->ops->op(args); \
163 #define call_vb_qop(vb, op, args...) \
164 ((vb)->vb2_queue->ops->op ? (vb)->vb2_queue->ops->op(args) : 0)
166 #define call_void_vb_qop(vb, op, args...) \
168 if ((vb)->vb2_queue->ops->op) \
169 (vb)->vb2_queue->ops->op(args); \
174 #define call_bufop(q, op, args...) \
177 if (q && q->buf_ops && q->buf_ops->op) \
178 ret = q->buf_ops->op(args); \
182 #define call_void_bufop(q, op, args...) \
184 if (q && q->buf_ops && q->buf_ops->op) \
185 q->buf_ops->op(args); \
188 static void __vb2_queue_cancel(struct vb2_queue *q);
189 static void __enqueue_in_driver(struct vb2_buffer *vb);
192 * __vb2_buf_mem_alloc() - allocate video memory for the given buffer
194 static int __vb2_buf_mem_alloc(struct vb2_buffer *vb)
196 struct vb2_queue *q = vb->vb2_queue;
197 enum dma_data_direction dma_dir =
198 q->is_output ? DMA_TO_DEVICE : DMA_FROM_DEVICE;
204 * Allocate memory for all planes in this buffer
205 * NOTE: mmapped areas should be page aligned
207 for (plane = 0; plane < vb->num_planes; ++plane) {
208 unsigned long size = PAGE_ALIGN(vb->planes[plane].length);
210 mem_priv = call_ptr_memop(vb, alloc,
211 q->alloc_devs[plane] ? : q->dev,
212 q->dma_attrs, size, dma_dir, q->gfp_flags);
213 if (IS_ERR(mem_priv)) {
215 ret = PTR_ERR(mem_priv);
219 /* Associate allocator private data with this plane */
220 vb->planes[plane].mem_priv = mem_priv;
225 /* Free already allocated memory if one of the allocations failed */
226 for (; plane > 0; --plane) {
227 call_void_memop(vb, put, vb->planes[plane - 1].mem_priv);
228 vb->planes[plane - 1].mem_priv = NULL;
235 * __vb2_buf_mem_free() - free memory of the given buffer
237 static void __vb2_buf_mem_free(struct vb2_buffer *vb)
241 for (plane = 0; plane < vb->num_planes; ++plane) {
242 call_void_memop(vb, put, vb->planes[plane].mem_priv);
243 vb->planes[plane].mem_priv = NULL;
244 dprintk(3, "freed plane %d of buffer %d\n", plane, vb->index);
249 * __vb2_buf_userptr_put() - release userspace memory associated with
252 static void __vb2_buf_userptr_put(struct vb2_buffer *vb)
256 for (plane = 0; plane < vb->num_planes; ++plane) {
257 if (vb->planes[plane].mem_priv)
258 call_void_memop(vb, put_userptr, vb->planes[plane].mem_priv);
259 vb->planes[plane].mem_priv = NULL;
264 * __vb2_plane_dmabuf_put() - release memory associated with
265 * a DMABUF shared plane
267 static void __vb2_plane_dmabuf_put(struct vb2_buffer *vb, struct vb2_plane *p)
273 call_void_memop(vb, unmap_dmabuf, p->mem_priv);
275 call_void_memop(vb, detach_dmabuf, p->mem_priv);
276 dma_buf_put(p->dbuf);
283 * __vb2_buf_dmabuf_put() - release memory associated with
284 * a DMABUF shared buffer
286 static void __vb2_buf_dmabuf_put(struct vb2_buffer *vb)
290 for (plane = 0; plane < vb->num_planes; ++plane)
291 __vb2_plane_dmabuf_put(vb, &vb->planes[plane]);
295 * __setup_offsets() - setup unique offsets ("cookies") for every plane in
298 static void __setup_offsets(struct vb2_buffer *vb)
300 struct vb2_queue *q = vb->vb2_queue;
302 unsigned long off = 0;
305 struct vb2_buffer *prev = q->bufs[vb->index - 1];
306 struct vb2_plane *p = &prev->planes[prev->num_planes - 1];
308 off = PAGE_ALIGN(p->m.offset + p->length);
311 for (plane = 0; plane < vb->num_planes; ++plane) {
312 vb->planes[plane].m.offset = off;
314 dprintk(3, "buffer %d, plane %d offset 0x%08lx\n",
315 vb->index, plane, off);
317 off += vb->planes[plane].length;
318 off = PAGE_ALIGN(off);
323 * __vb2_queue_alloc() - allocate videobuf buffer structures and (for MMAP type)
324 * video buffer memory for all buffers/planes on the queue and initializes the
327 * Returns the number of buffers successfully allocated.
329 static int __vb2_queue_alloc(struct vb2_queue *q, enum vb2_memory memory,
330 unsigned int num_buffers, unsigned int num_planes,
331 const unsigned plane_sizes[VB2_MAX_PLANES])
333 unsigned int buffer, plane;
334 struct vb2_buffer *vb;
337 for (buffer = 0; buffer < num_buffers; ++buffer) {
338 /* Allocate videobuf buffer structures */
339 vb = kzalloc(q->buf_struct_size, GFP_KERNEL);
341 dprintk(1, "memory alloc for buffer struct failed\n");
345 vb->state = VB2_BUF_STATE_DEQUEUED;
347 vb->num_planes = num_planes;
348 vb->index = q->num_buffers + buffer;
351 for (plane = 0; plane < num_planes; ++plane) {
352 vb->planes[plane].length = plane_sizes[plane];
353 vb->planes[plane].min_length = plane_sizes[plane];
355 q->bufs[vb->index] = vb;
357 /* Allocate video buffer memory for the MMAP type */
358 if (memory == VB2_MEMORY_MMAP) {
359 ret = __vb2_buf_mem_alloc(vb);
361 dprintk(1, "failed allocating memory for "
362 "buffer %d\n", buffer);
363 q->bufs[vb->index] = NULL;
369 * Call the driver-provided buffer initialization
370 * callback, if given. An error in initialization
371 * results in queue setup failure.
373 ret = call_vb_qop(vb, buf_init, vb);
375 dprintk(1, "buffer %d %p initialization"
376 " failed\n", buffer, vb);
377 __vb2_buf_mem_free(vb);
378 q->bufs[vb->index] = NULL;
385 dprintk(1, "allocated %d buffers, %d plane(s) each\n",
392 * __vb2_free_mem() - release all video buffer memory for a given queue
394 static void __vb2_free_mem(struct vb2_queue *q, unsigned int buffers)
397 struct vb2_buffer *vb;
399 for (buffer = q->num_buffers - buffers; buffer < q->num_buffers;
401 vb = q->bufs[buffer];
405 /* Free MMAP buffers or release USERPTR buffers */
406 if (q->memory == VB2_MEMORY_MMAP)
407 __vb2_buf_mem_free(vb);
408 else if (q->memory == VB2_MEMORY_DMABUF)
409 __vb2_buf_dmabuf_put(vb);
411 __vb2_buf_userptr_put(vb);
416 * __vb2_queue_free() - free buffers at the end of the queue - video memory and
417 * related information, if no buffers are left return the queue to an
418 * uninitialized state. Might be called even if the queue has already been freed.
420 static int __vb2_queue_free(struct vb2_queue *q, unsigned int buffers)
425 * Sanity check: when preparing a buffer the queue lock is released for
426 * a short while (see __buf_prepare for the details), which would allow
427 * a race with a reqbufs which can call this function. Removing the
428 * buffers from underneath __buf_prepare is obviously a bad idea, so we
429 * check if any of the buffers is in the state PREPARING, and if so we
430 * just return -EAGAIN.
432 for (buffer = q->num_buffers - buffers; buffer < q->num_buffers;
434 if (q->bufs[buffer] == NULL)
436 if (q->bufs[buffer]->state == VB2_BUF_STATE_PREPARING) {
437 dprintk(1, "preparing buffers, cannot free\n");
442 /* Call driver-provided cleanup function for each buffer, if provided */
443 for (buffer = q->num_buffers - buffers; buffer < q->num_buffers;
445 struct vb2_buffer *vb = q->bufs[buffer];
447 if (vb && vb->planes[0].mem_priv)
448 call_void_vb_qop(vb, buf_cleanup, vb);
451 /* Release video buffer memory */
452 __vb2_free_mem(q, buffers);
454 #ifdef CONFIG_VIDEO_ADV_DEBUG
456 * Check that all the calls were balances during the life-time of this
457 * queue. If not (or if the debug level is 1 or up), then dump the
458 * counters to the kernel log.
460 if (q->num_buffers) {
461 bool unbalanced = q->cnt_start_streaming != q->cnt_stop_streaming ||
462 q->cnt_wait_prepare != q->cnt_wait_finish;
464 if (unbalanced || debug) {
465 pr_info("vb2: counters for queue %p:%s\n", q,
466 unbalanced ? " UNBALANCED!" : "");
467 pr_info("vb2: setup: %u start_streaming: %u stop_streaming: %u\n",
468 q->cnt_queue_setup, q->cnt_start_streaming,
469 q->cnt_stop_streaming);
470 pr_info("vb2: wait_prepare: %u wait_finish: %u\n",
471 q->cnt_wait_prepare, q->cnt_wait_finish);
473 q->cnt_queue_setup = 0;
474 q->cnt_wait_prepare = 0;
475 q->cnt_wait_finish = 0;
476 q->cnt_start_streaming = 0;
477 q->cnt_stop_streaming = 0;
479 for (buffer = 0; buffer < q->num_buffers; ++buffer) {
480 struct vb2_buffer *vb = q->bufs[buffer];
481 bool unbalanced = vb->cnt_mem_alloc != vb->cnt_mem_put ||
482 vb->cnt_mem_prepare != vb->cnt_mem_finish ||
483 vb->cnt_mem_get_userptr != vb->cnt_mem_put_userptr ||
484 vb->cnt_mem_attach_dmabuf != vb->cnt_mem_detach_dmabuf ||
485 vb->cnt_mem_map_dmabuf != vb->cnt_mem_unmap_dmabuf ||
486 vb->cnt_buf_queue != vb->cnt_buf_done ||
487 vb->cnt_buf_prepare != vb->cnt_buf_finish ||
488 vb->cnt_buf_init != vb->cnt_buf_cleanup;
490 if (unbalanced || debug) {
491 pr_info("vb2: counters for queue %p, buffer %d:%s\n",
492 q, buffer, unbalanced ? " UNBALANCED!" : "");
493 pr_info("vb2: buf_init: %u buf_cleanup: %u buf_prepare: %u buf_finish: %u\n",
494 vb->cnt_buf_init, vb->cnt_buf_cleanup,
495 vb->cnt_buf_prepare, vb->cnt_buf_finish);
496 pr_info("vb2: buf_queue: %u buf_done: %u\n",
497 vb->cnt_buf_queue, vb->cnt_buf_done);
498 pr_info("vb2: alloc: %u put: %u prepare: %u finish: %u mmap: %u\n",
499 vb->cnt_mem_alloc, vb->cnt_mem_put,
500 vb->cnt_mem_prepare, vb->cnt_mem_finish,
502 pr_info("vb2: get_userptr: %u put_userptr: %u\n",
503 vb->cnt_mem_get_userptr, vb->cnt_mem_put_userptr);
504 pr_info("vb2: attach_dmabuf: %u detach_dmabuf: %u map_dmabuf: %u unmap_dmabuf: %u\n",
505 vb->cnt_mem_attach_dmabuf, vb->cnt_mem_detach_dmabuf,
506 vb->cnt_mem_map_dmabuf, vb->cnt_mem_unmap_dmabuf);
507 pr_info("vb2: get_dmabuf: %u num_users: %u vaddr: %u cookie: %u\n",
508 vb->cnt_mem_get_dmabuf,
509 vb->cnt_mem_num_users,
516 /* Free videobuf buffers */
517 for (buffer = q->num_buffers - buffers; buffer < q->num_buffers;
519 kfree(q->bufs[buffer]);
520 q->bufs[buffer] = NULL;
523 q->num_buffers -= buffers;
524 if (!q->num_buffers) {
526 INIT_LIST_HEAD(&q->queued_list);
532 * vb2_buffer_in_use() - return true if the buffer is in use and
533 * the queue cannot be freed (by the means of REQBUFS(0)) call
535 bool vb2_buffer_in_use(struct vb2_queue *q, struct vb2_buffer *vb)
538 for (plane = 0; plane < vb->num_planes; ++plane) {
539 void *mem_priv = vb->planes[plane].mem_priv;
541 * If num_users() has not been provided, call_memop
542 * will return 0, apparently nobody cares about this
543 * case anyway. If num_users() returns more than 1,
544 * we are not the only user of the plane's memory.
546 if (mem_priv && call_memop(vb, num_users, mem_priv) > 1)
551 EXPORT_SYMBOL(vb2_buffer_in_use);
554 * __buffers_in_use() - return true if any buffers on the queue are in use and
555 * the queue cannot be freed (by the means of REQBUFS(0)) call
557 static bool __buffers_in_use(struct vb2_queue *q)
560 for (buffer = 0; buffer < q->num_buffers; ++buffer) {
561 if (vb2_buffer_in_use(q, q->bufs[buffer]))
568 * vb2_core_querybuf() - query video buffer information
570 * @index: id number of the buffer
571 * @pb: buffer struct passed from userspace
573 * Should be called from vidioc_querybuf ioctl handler in driver.
574 * The passed buffer should have been verified.
575 * This function fills the relevant information for the userspace.
577 void vb2_core_querybuf(struct vb2_queue *q, unsigned int index, void *pb)
579 call_void_bufop(q, fill_user_buffer, q->bufs[index], pb);
581 EXPORT_SYMBOL_GPL(vb2_core_querybuf);
584 * __verify_userptr_ops() - verify that all memory operations required for
585 * USERPTR queue type have been provided
587 static int __verify_userptr_ops(struct vb2_queue *q)
589 if (!(q->io_modes & VB2_USERPTR) || !q->mem_ops->get_userptr ||
590 !q->mem_ops->put_userptr)
597 * __verify_mmap_ops() - verify that all memory operations required for
598 * MMAP queue type have been provided
600 static int __verify_mmap_ops(struct vb2_queue *q)
602 if (!(q->io_modes & VB2_MMAP) || !q->mem_ops->alloc ||
603 !q->mem_ops->put || !q->mem_ops->mmap)
610 * __verify_dmabuf_ops() - verify that all memory operations required for
611 * DMABUF queue type have been provided
613 static int __verify_dmabuf_ops(struct vb2_queue *q)
615 if (!(q->io_modes & VB2_DMABUF) || !q->mem_ops->attach_dmabuf ||
616 !q->mem_ops->detach_dmabuf || !q->mem_ops->map_dmabuf ||
617 !q->mem_ops->unmap_dmabuf)
624 * vb2_verify_memory_type() - Check whether the memory type and buffer type
625 * passed to a buffer operation are compatible with the queue.
627 int vb2_verify_memory_type(struct vb2_queue *q,
628 enum vb2_memory memory, unsigned int type)
630 if (memory != VB2_MEMORY_MMAP && memory != VB2_MEMORY_USERPTR &&
631 memory != VB2_MEMORY_DMABUF) {
632 dprintk(1, "unsupported memory type\n");
636 if (type != q->type) {
637 dprintk(1, "requested type is incorrect\n");
642 * Make sure all the required memory ops for given memory type
645 if (memory == VB2_MEMORY_MMAP && __verify_mmap_ops(q)) {
646 dprintk(1, "MMAP for current setup unsupported\n");
650 if (memory == VB2_MEMORY_USERPTR && __verify_userptr_ops(q)) {
651 dprintk(1, "USERPTR for current setup unsupported\n");
655 if (memory == VB2_MEMORY_DMABUF && __verify_dmabuf_ops(q)) {
656 dprintk(1, "DMABUF for current setup unsupported\n");
661 * Place the busy tests at the end: -EBUSY can be ignored when
662 * create_bufs is called with count == 0, but count == 0 should still
663 * do the memory and type validation.
665 if (vb2_fileio_is_active(q)) {
666 dprintk(1, "file io in progress\n");
671 EXPORT_SYMBOL(vb2_verify_memory_type);
674 * vb2_core_reqbufs() - Initiate streaming
675 * @q: videobuf2 queue
676 * @memory: memory type
677 * @count: requested buffer count
679 * Should be called from vidioc_reqbufs ioctl handler of a driver.
681 * 1) verifies streaming parameters passed from the userspace,
682 * 2) sets up the queue,
683 * 3) negotiates number of buffers and planes per buffer with the driver
684 * to be used during streaming,
685 * 4) allocates internal buffer structures (struct vb2_buffer), according to
686 * the agreed parameters,
687 * 5) for MMAP memory type, allocates actual video memory, using the
688 * memory handling/allocation routines provided during queue initialization
690 * If req->count is 0, all the memory will be freed instead.
691 * If the queue has been allocated previously (by a previous vb2_reqbufs) call
692 * and the queue is not busy, memory will be reallocated.
694 * The return values from this function are intended to be directly returned
695 * from vidioc_reqbufs handler in driver.
697 int vb2_core_reqbufs(struct vb2_queue *q, enum vb2_memory memory,
700 unsigned int num_buffers, allocated_buffers, num_planes = 0;
701 unsigned plane_sizes[VB2_MAX_PLANES] = { };
705 dprintk(1, "streaming active\n");
709 if (*count == 0 || q->num_buffers != 0 || q->memory != memory) {
711 * We already have buffers allocated, so first check if they
712 * are not in use and can be freed.
714 mutex_lock(&q->mmap_lock);
715 if (q->memory == VB2_MEMORY_MMAP && __buffers_in_use(q)) {
716 mutex_unlock(&q->mmap_lock);
717 dprintk(1, "memory in use, cannot free\n");
722 * Call queue_cancel to clean up any buffers in the PREPARED or
723 * QUEUED state which is possible if buffers were prepared or
724 * queued without ever calling STREAMON.
726 __vb2_queue_cancel(q);
727 ret = __vb2_queue_free(q, q->num_buffers);
728 mutex_unlock(&q->mmap_lock);
733 * In case of REQBUFS(0) return immediately without calling
734 * driver's queue_setup() callback and allocating resources.
741 * Make sure the requested values and current defaults are sane.
743 num_buffers = min_t(unsigned int, *count, VB2_MAX_FRAME);
744 num_buffers = max_t(unsigned int, num_buffers, q->min_buffers_needed);
745 memset(q->alloc_devs, 0, sizeof(q->alloc_devs));
749 * Ask the driver how many buffers and planes per buffer it requires.
750 * Driver also sets the size and allocator context for each plane.
752 ret = call_qop(q, queue_setup, q, &num_buffers, &num_planes,
753 plane_sizes, q->alloc_devs);
757 /* Finally, allocate buffers and video memory */
759 __vb2_queue_alloc(q, memory, num_buffers, num_planes, plane_sizes);
760 if (allocated_buffers == 0) {
761 dprintk(1, "memory allocation failed\n");
766 * There is no point in continuing if we can't allocate the minimum
767 * number of buffers needed by this vb2_queue.
769 if (allocated_buffers < q->min_buffers_needed)
773 * Check if driver can handle the allocated number of buffers.
775 if (!ret && allocated_buffers < num_buffers) {
776 num_buffers = allocated_buffers;
778 * num_planes is set by the previous queue_setup(), but since it
779 * signals to queue_setup() whether it is called from create_bufs()
780 * vs reqbufs() we zero it here to signal that queue_setup() is
781 * called for the reqbufs() case.
785 ret = call_qop(q, queue_setup, q, &num_buffers,
786 &num_planes, plane_sizes, q->alloc_devs);
788 if (!ret && allocated_buffers < num_buffers)
792 * Either the driver has accepted a smaller number of buffers,
793 * or .queue_setup() returned an error
797 mutex_lock(&q->mmap_lock);
798 q->num_buffers = allocated_buffers;
802 * Note: __vb2_queue_free() will subtract 'allocated_buffers'
803 * from q->num_buffers.
805 __vb2_queue_free(q, allocated_buffers);
806 mutex_unlock(&q->mmap_lock);
809 mutex_unlock(&q->mmap_lock);
812 * Return the number of successfully allocated buffers
815 *count = allocated_buffers;
816 q->waiting_for_buffers = !q->is_output;
820 EXPORT_SYMBOL_GPL(vb2_core_reqbufs);
823 * vb2_core_create_bufs() - Allocate buffers and any required auxiliary structs
824 * @q: videobuf2 queue
825 * @memory: memory type
826 * @count: requested buffer count
827 * @parg: parameter passed to device driver
829 * Should be called from vidioc_create_bufs ioctl handler of a driver.
831 * 1) verifies parameter sanity
832 * 2) calls the .queue_setup() queue operation
833 * 3) performs any necessary memory allocations
835 * The return values from this function are intended to be directly returned
836 * from vidioc_create_bufs handler in driver.
838 int vb2_core_create_bufs(struct vb2_queue *q, enum vb2_memory memory,
839 unsigned int *count, unsigned requested_planes,
840 const unsigned requested_sizes[])
842 unsigned int num_planes = 0, num_buffers, allocated_buffers;
843 unsigned plane_sizes[VB2_MAX_PLANES] = { };
846 if (q->num_buffers == VB2_MAX_FRAME) {
847 dprintk(1, "maximum number of buffers already allocated\n");
851 if (!q->num_buffers) {
852 memset(q->alloc_devs, 0, sizeof(q->alloc_devs));
854 q->waiting_for_buffers = !q->is_output;
857 num_buffers = min(*count, VB2_MAX_FRAME - q->num_buffers);
859 if (requested_planes && requested_sizes) {
860 num_planes = requested_planes;
861 memcpy(plane_sizes, requested_sizes, sizeof(plane_sizes));
865 * Ask the driver, whether the requested number of buffers, planes per
866 * buffer and their sizes are acceptable
868 ret = call_qop(q, queue_setup, q, &num_buffers,
869 &num_planes, plane_sizes, q->alloc_devs);
873 /* Finally, allocate buffers and video memory */
874 allocated_buffers = __vb2_queue_alloc(q, memory, num_buffers,
875 num_planes, plane_sizes);
876 if (allocated_buffers == 0) {
877 dprintk(1, "memory allocation failed\n");
882 * Check if driver can handle the so far allocated number of buffers.
884 if (allocated_buffers < num_buffers) {
885 num_buffers = allocated_buffers;
888 * q->num_buffers contains the total number of buffers, that the
889 * queue driver has set up
891 ret = call_qop(q, queue_setup, q, &num_buffers,
892 &num_planes, plane_sizes, q->alloc_devs);
894 if (!ret && allocated_buffers < num_buffers)
898 * Either the driver has accepted a smaller number of buffers,
899 * or .queue_setup() returned an error
903 mutex_lock(&q->mmap_lock);
904 q->num_buffers += allocated_buffers;
908 * Note: __vb2_queue_free() will subtract 'allocated_buffers'
909 * from q->num_buffers.
911 __vb2_queue_free(q, allocated_buffers);
912 mutex_unlock(&q->mmap_lock);
915 mutex_unlock(&q->mmap_lock);
918 * Return the number of successfully allocated buffers
921 *count = allocated_buffers;
925 EXPORT_SYMBOL_GPL(vb2_core_create_bufs);
928 * vb2_plane_vaddr() - Return a kernel virtual address of a given plane
929 * @vb: vb2_buffer to which the plane in question belongs to
930 * @plane_no: plane number for which the address is to be returned
932 * This function returns a kernel virtual address of a given plane if
933 * such a mapping exist, NULL otherwise.
935 void *vb2_plane_vaddr(struct vb2_buffer *vb, unsigned int plane_no)
937 if (plane_no > vb->num_planes || !vb->planes[plane_no].mem_priv)
940 return call_ptr_memop(vb, vaddr, vb->planes[plane_no].mem_priv);
943 EXPORT_SYMBOL_GPL(vb2_plane_vaddr);
946 * vb2_plane_cookie() - Return allocator specific cookie for the given plane
947 * @vb: vb2_buffer to which the plane in question belongs to
948 * @plane_no: plane number for which the cookie is to be returned
950 * This function returns an allocator specific cookie for a given plane if
951 * available, NULL otherwise. The allocator should provide some simple static
952 * inline function, which would convert this cookie to the allocator specific
953 * type that can be used directly by the driver to access the buffer. This can
954 * be for example physical address, pointer to scatter list or IOMMU mapping.
956 void *vb2_plane_cookie(struct vb2_buffer *vb, unsigned int plane_no)
958 if (plane_no >= vb->num_planes || !vb->planes[plane_no].mem_priv)
961 return call_ptr_memop(vb, cookie, vb->planes[plane_no].mem_priv);
963 EXPORT_SYMBOL_GPL(vb2_plane_cookie);
966 * vb2_buffer_done() - inform videobuf that an operation on a buffer is finished
967 * @vb: vb2_buffer returned from the driver
968 * @state: either VB2_BUF_STATE_DONE if the operation finished successfully,
969 * VB2_BUF_STATE_ERROR if the operation finished with an error or
970 * VB2_BUF_STATE_QUEUED if the driver wants to requeue buffers.
971 * If start_streaming fails then it should return buffers with state
972 * VB2_BUF_STATE_QUEUED to put them back into the queue.
974 * This function should be called by the driver after a hardware operation on
975 * a buffer is finished and the buffer may be returned to userspace. The driver
976 * cannot use this buffer anymore until it is queued back to it by videobuf
977 * by the means of buf_queue callback. Only buffers previously queued to the
978 * driver by buf_queue can be passed to this function.
980 * While streaming a buffer can only be returned in state DONE or ERROR.
981 * The start_streaming op can also return them in case the DMA engine cannot
982 * be started for some reason. In that case the buffers should be returned with
985 void vb2_buffer_done(struct vb2_buffer *vb, enum vb2_buffer_state state)
987 struct vb2_queue *q = vb->vb2_queue;
991 if (WARN_ON(vb->state != VB2_BUF_STATE_ACTIVE))
994 if (WARN_ON(state != VB2_BUF_STATE_DONE &&
995 state != VB2_BUF_STATE_ERROR &&
996 state != VB2_BUF_STATE_QUEUED &&
997 state != VB2_BUF_STATE_REQUEUEING))
998 state = VB2_BUF_STATE_ERROR;
1000 #ifdef CONFIG_VIDEO_ADV_DEBUG
1002 * Although this is not a callback, it still does have to balance
1003 * with the buf_queue op. So update this counter manually.
1007 dprintk(4, "done processing on buffer %d, state: %d\n",
1011 for (plane = 0; plane < vb->num_planes; ++plane)
1012 call_void_memop(vb, finish, vb->planes[plane].mem_priv);
1014 spin_lock_irqsave(&q->done_lock, flags);
1015 if (state == VB2_BUF_STATE_QUEUED ||
1016 state == VB2_BUF_STATE_REQUEUEING) {
1017 vb->state = VB2_BUF_STATE_QUEUED;
1019 /* Add the buffer to the done buffers list */
1020 list_add_tail(&vb->done_entry, &q->done_list);
1023 atomic_dec(&q->owned_by_drv_count);
1024 spin_unlock_irqrestore(&q->done_lock, flags);
1026 trace_vb2_buf_done(q, vb);
1029 case VB2_BUF_STATE_QUEUED:
1031 case VB2_BUF_STATE_REQUEUEING:
1032 if (q->start_streaming_called)
1033 __enqueue_in_driver(vb);
1036 /* Inform any processes that may be waiting for buffers */
1037 wake_up(&q->done_wq);
1041 EXPORT_SYMBOL_GPL(vb2_buffer_done);
1044 * vb2_discard_done() - discard all buffers marked as DONE
1045 * @q: videobuf2 queue
1047 * This function is intended to be used with suspend/resume operations. It
1048 * discards all 'done' buffers as they would be too old to be requested after
1051 * Drivers must stop the hardware and synchronize with interrupt handlers and/or
1052 * delayed works before calling this function to make sure no buffer will be
1053 * touched by the driver and/or hardware.
1055 void vb2_discard_done(struct vb2_queue *q)
1057 struct vb2_buffer *vb;
1058 unsigned long flags;
1060 spin_lock_irqsave(&q->done_lock, flags);
1061 list_for_each_entry(vb, &q->done_list, done_entry)
1062 vb->state = VB2_BUF_STATE_ERROR;
1063 spin_unlock_irqrestore(&q->done_lock, flags);
1065 EXPORT_SYMBOL_GPL(vb2_discard_done);
1068 * __qbuf_mmap() - handle qbuf of an MMAP buffer
1070 static int __qbuf_mmap(struct vb2_buffer *vb, const void *pb)
1075 ret = call_bufop(vb->vb2_queue, fill_vb2_buffer,
1076 vb, pb, vb->planes);
1077 return ret ? ret : call_vb_qop(vb, buf_prepare, vb);
1081 * __qbuf_userptr() - handle qbuf of a USERPTR buffer
1083 static int __qbuf_userptr(struct vb2_buffer *vb, const void *pb)
1085 struct vb2_plane planes[VB2_MAX_PLANES];
1086 struct vb2_queue *q = vb->vb2_queue;
1090 enum dma_data_direction dma_dir =
1091 q->is_output ? DMA_TO_DEVICE : DMA_FROM_DEVICE;
1092 bool reacquired = vb->planes[0].mem_priv == NULL;
1094 memset(planes, 0, sizeof(planes[0]) * vb->num_planes);
1095 /* Copy relevant information provided by the userspace */
1097 ret = call_bufop(vb->vb2_queue, fill_vb2_buffer,
1102 for (plane = 0; plane < vb->num_planes; ++plane) {
1103 /* Skip the plane if already verified */
1104 if (vb->planes[plane].m.userptr &&
1105 vb->planes[plane].m.userptr == planes[plane].m.userptr
1106 && vb->planes[plane].length == planes[plane].length)
1109 dprintk(3, "userspace address for plane %d changed, "
1110 "reacquiring memory\n", plane);
1112 /* Check if the provided plane buffer is large enough */
1113 if (planes[plane].length < vb->planes[plane].min_length) {
1114 dprintk(1, "provided buffer size %u is less than "
1115 "setup size %u for plane %d\n",
1116 planes[plane].length,
1117 vb->planes[plane].min_length,
1123 /* Release previously acquired memory if present */
1124 if (vb->planes[plane].mem_priv) {
1127 call_void_vb_qop(vb, buf_cleanup, vb);
1129 call_void_memop(vb, put_userptr, vb->planes[plane].mem_priv);
1132 vb->planes[plane].mem_priv = NULL;
1133 vb->planes[plane].bytesused = 0;
1134 vb->planes[plane].length = 0;
1135 vb->planes[plane].m.userptr = 0;
1136 vb->planes[plane].data_offset = 0;
1138 /* Acquire each plane's memory */
1139 mem_priv = call_ptr_memop(vb, get_userptr,
1140 q->alloc_devs[plane] ? : q->dev,
1141 planes[plane].m.userptr,
1142 planes[plane].length, dma_dir);
1143 if (IS_ERR(mem_priv)) {
1144 dprintk(1, "failed acquiring userspace "
1145 "memory for plane %d\n", plane);
1146 ret = PTR_ERR(mem_priv);
1149 vb->planes[plane].mem_priv = mem_priv;
1153 * Now that everything is in order, copy relevant information
1154 * provided by userspace.
1156 for (plane = 0; plane < vb->num_planes; ++plane) {
1157 vb->planes[plane].bytesused = planes[plane].bytesused;
1158 vb->planes[plane].length = planes[plane].length;
1159 vb->planes[plane].m.userptr = planes[plane].m.userptr;
1160 vb->planes[plane].data_offset = planes[plane].data_offset;
1165 * One or more planes changed, so we must call buf_init to do
1166 * the driver-specific initialization on the newly acquired
1167 * buffer, if provided.
1169 ret = call_vb_qop(vb, buf_init, vb);
1171 dprintk(1, "buffer initialization failed\n");
1176 ret = call_vb_qop(vb, buf_prepare, vb);
1178 dprintk(1, "buffer preparation failed\n");
1179 call_void_vb_qop(vb, buf_cleanup, vb);
1185 /* In case of errors, release planes that were already acquired */
1186 for (plane = 0; plane < vb->num_planes; ++plane) {
1187 if (vb->planes[plane].mem_priv)
1188 call_void_memop(vb, put_userptr,
1189 vb->planes[plane].mem_priv);
1190 vb->planes[plane].mem_priv = NULL;
1191 vb->planes[plane].m.userptr = 0;
1192 vb->planes[plane].length = 0;
1199 * __qbuf_dmabuf() - handle qbuf of a DMABUF buffer
1201 static int __qbuf_dmabuf(struct vb2_buffer *vb, const void *pb)
1203 struct vb2_plane planes[VB2_MAX_PLANES];
1204 struct vb2_queue *q = vb->vb2_queue;
1208 enum dma_data_direction dma_dir =
1209 q->is_output ? DMA_TO_DEVICE : DMA_FROM_DEVICE;
1210 bool reacquired = vb->planes[0].mem_priv == NULL;
1212 memset(planes, 0, sizeof(planes[0]) * vb->num_planes);
1213 /* Copy relevant information provided by the userspace */
1215 ret = call_bufop(vb->vb2_queue, fill_vb2_buffer,
1220 for (plane = 0; plane < vb->num_planes; ++plane) {
1221 struct dma_buf *dbuf = dma_buf_get(planes[plane].m.fd);
1223 if (IS_ERR_OR_NULL(dbuf)) {
1224 dprintk(1, "invalid dmabuf fd for plane %d\n",
1230 /* use DMABUF size if length is not provided */
1231 if (planes[plane].length == 0)
1232 planes[plane].length = dbuf->size;
1234 if (planes[plane].length < vb->planes[plane].min_length) {
1235 dprintk(1, "invalid dmabuf length %u for plane %d, "
1236 "minimum length %u\n",
1237 planes[plane].length, plane,
1238 vb->planes[plane].min_length);
1244 /* Skip the plane if already verified */
1245 if (dbuf == vb->planes[plane].dbuf &&
1246 vb->planes[plane].length == planes[plane].length) {
1251 dprintk(1, "buffer for plane %d changed\n", plane);
1255 call_void_vb_qop(vb, buf_cleanup, vb);
1258 /* Release previously acquired memory if present */
1259 __vb2_plane_dmabuf_put(vb, &vb->planes[plane]);
1260 vb->planes[plane].bytesused = 0;
1261 vb->planes[plane].length = 0;
1262 vb->planes[plane].m.fd = 0;
1263 vb->planes[plane].data_offset = 0;
1265 /* Acquire each plane's memory */
1266 mem_priv = call_ptr_memop(vb, attach_dmabuf,
1267 q->alloc_devs[plane] ? : q->dev,
1268 dbuf, planes[plane].length, dma_dir);
1269 if (IS_ERR(mem_priv)) {
1270 dprintk(1, "failed to attach dmabuf\n");
1271 ret = PTR_ERR(mem_priv);
1276 vb->planes[plane].dbuf = dbuf;
1277 vb->planes[plane].mem_priv = mem_priv;
1281 * This pins the buffer(s) with dma_buf_map_attachment()). It's done
1282 * here instead just before the DMA, while queueing the buffer(s) so
1283 * userspace knows sooner rather than later if the dma-buf map fails.
1285 for (plane = 0; plane < vb->num_planes; ++plane) {
1286 ret = call_memop(vb, map_dmabuf, vb->planes[plane].mem_priv);
1288 dprintk(1, "failed to map dmabuf for plane %d\n",
1292 vb->planes[plane].dbuf_mapped = 1;
1296 * Now that everything is in order, copy relevant information
1297 * provided by userspace.
1299 for (plane = 0; plane < vb->num_planes; ++plane) {
1300 vb->planes[plane].bytesused = planes[plane].bytesused;
1301 vb->planes[plane].length = planes[plane].length;
1302 vb->planes[plane].m.fd = planes[plane].m.fd;
1303 vb->planes[plane].data_offset = planes[plane].data_offset;
1308 * Call driver-specific initialization on the newly acquired buffer,
1311 ret = call_vb_qop(vb, buf_init, vb);
1313 dprintk(1, "buffer initialization failed\n");
1318 ret = call_vb_qop(vb, buf_prepare, vb);
1320 dprintk(1, "buffer preparation failed\n");
1321 call_void_vb_qop(vb, buf_cleanup, vb);
1327 /* In case of errors, release planes that were already acquired */
1328 __vb2_buf_dmabuf_put(vb);
1334 * __enqueue_in_driver() - enqueue a vb2_buffer in driver for processing
1336 static void __enqueue_in_driver(struct vb2_buffer *vb)
1338 struct vb2_queue *q = vb->vb2_queue;
1341 vb->state = VB2_BUF_STATE_ACTIVE;
1342 atomic_inc(&q->owned_by_drv_count);
1344 trace_vb2_buf_queue(q, vb);
1347 for (plane = 0; plane < vb->num_planes; ++plane)
1348 call_void_memop(vb, prepare, vb->planes[plane].mem_priv);
1350 call_void_vb_qop(vb, buf_queue, vb);
1353 static int __buf_prepare(struct vb2_buffer *vb, const void *pb)
1355 struct vb2_queue *q = vb->vb2_queue;
1359 dprintk(1, "fatal error occurred on queue\n");
1363 vb->state = VB2_BUF_STATE_PREPARING;
1365 switch (q->memory) {
1366 case VB2_MEMORY_MMAP:
1367 ret = __qbuf_mmap(vb, pb);
1369 case VB2_MEMORY_USERPTR:
1370 ret = __qbuf_userptr(vb, pb);
1372 case VB2_MEMORY_DMABUF:
1373 ret = __qbuf_dmabuf(vb, pb);
1376 WARN(1, "Invalid queue type\n");
1381 dprintk(1, "buffer preparation failed: %d\n", ret);
1382 vb->state = ret ? VB2_BUF_STATE_DEQUEUED : VB2_BUF_STATE_PREPARED;
1388 * vb2_core_prepare_buf() - Pass ownership of a buffer from userspace
1390 * @q: videobuf2 queue
1391 * @index: id number of the buffer
1392 * @pb: buffer structure passed from userspace to vidioc_prepare_buf
1395 * Should be called from vidioc_prepare_buf ioctl handler of a driver.
1396 * The passed buffer should have been verified.
1397 * This function calls buf_prepare callback in the driver (if provided),
1398 * in which driver-specific buffer initialization can be performed,
1400 * The return values from this function are intended to be directly returned
1401 * from vidioc_prepare_buf handler in driver.
1403 int vb2_core_prepare_buf(struct vb2_queue *q, unsigned int index, void *pb)
1405 struct vb2_buffer *vb;
1408 vb = q->bufs[index];
1409 if (vb->state != VB2_BUF_STATE_DEQUEUED) {
1410 dprintk(1, "invalid buffer state %d\n",
1415 ret = __buf_prepare(vb, pb);
1419 /* Fill buffer information for the userspace */
1420 call_void_bufop(q, fill_user_buffer, vb, pb);
1422 dprintk(1, "prepare of buffer %d succeeded\n", vb->index);
1426 EXPORT_SYMBOL_GPL(vb2_core_prepare_buf);
1429 * vb2_start_streaming() - Attempt to start streaming.
1430 * @q: videobuf2 queue
1432 * Attempt to start streaming. When this function is called there must be
1433 * at least q->min_buffers_needed buffers queued up (i.e. the minimum
1434 * number of buffers required for the DMA engine to function). If the
1435 * @start_streaming op fails it is supposed to return all the driver-owned
1436 * buffers back to vb2 in state QUEUED. Check if that happened and if
1437 * not warn and reclaim them forcefully.
1439 static int vb2_start_streaming(struct vb2_queue *q)
1441 struct vb2_buffer *vb;
1445 * If any buffers were queued before streamon,
1446 * we can now pass them to driver for processing.
1448 list_for_each_entry(vb, &q->queued_list, queued_entry)
1449 __enqueue_in_driver(vb);
1451 /* Tell the driver to start streaming */
1452 q->start_streaming_called = 1;
1453 ret = call_qop(q, start_streaming, q,
1454 atomic_read(&q->owned_by_drv_count));
1458 q->start_streaming_called = 0;
1460 dprintk(1, "driver refused to start streaming\n");
1462 * If you see this warning, then the driver isn't cleaning up properly
1463 * after a failed start_streaming(). See the start_streaming()
1464 * documentation in videobuf2-core.h for more information how buffers
1465 * should be returned to vb2 in start_streaming().
1467 if (WARN_ON(atomic_read(&q->owned_by_drv_count))) {
1471 * Forcefully reclaim buffers if the driver did not
1472 * correctly return them to vb2.
1474 for (i = 0; i < q->num_buffers; ++i) {
1476 if (vb->state == VB2_BUF_STATE_ACTIVE)
1477 vb2_buffer_done(vb, VB2_BUF_STATE_QUEUED);
1479 /* Must be zero now */
1480 WARN_ON(atomic_read(&q->owned_by_drv_count));
1483 * If done_list is not empty, then start_streaming() didn't call
1484 * vb2_buffer_done(vb, VB2_BUF_STATE_QUEUED) but STATE_ERROR or
1487 WARN_ON(!list_empty(&q->done_list));
1492 * vb2_core_qbuf() - Queue a buffer from userspace
1493 * @q: videobuf2 queue
1494 * @index: id number of the buffer
1495 * @pb: buffer structure passed from userspace to vidioc_qbuf handler
1498 * Should be called from vidioc_qbuf ioctl handler of a driver.
1499 * The passed buffer should have been verified.
1501 * 1) if necessary, calls buf_prepare callback in the driver (if provided), in
1502 * which driver-specific buffer initialization can be performed,
1503 * 2) if streaming is on, queues the buffer in driver by the means of buf_queue
1504 * callback for processing.
1506 * The return values from this function are intended to be directly returned
1507 * from vidioc_qbuf handler in driver.
1509 int vb2_core_qbuf(struct vb2_queue *q, unsigned int index, void *pb)
1511 struct vb2_buffer *vb;
1514 vb = q->bufs[index];
1516 switch (vb->state) {
1517 case VB2_BUF_STATE_DEQUEUED:
1518 ret = __buf_prepare(vb, pb);
1522 case VB2_BUF_STATE_PREPARED:
1524 case VB2_BUF_STATE_PREPARING:
1525 dprintk(1, "buffer still being prepared\n");
1528 dprintk(1, "invalid buffer state %d\n", vb->state);
1533 * Add to the queued buffers list, a buffer will stay on it until
1534 * dequeued in dqbuf.
1536 list_add_tail(&vb->queued_entry, &q->queued_list);
1538 q->waiting_for_buffers = false;
1539 vb->state = VB2_BUF_STATE_QUEUED;
1542 call_void_bufop(q, copy_timestamp, vb, pb);
1544 trace_vb2_qbuf(q, vb);
1547 * If already streaming, give the buffer to driver for processing.
1548 * If not, the buffer will be given to driver on next streamon.
1550 if (q->start_streaming_called)
1551 __enqueue_in_driver(vb);
1553 /* Fill buffer information for the userspace */
1555 call_void_bufop(q, fill_user_buffer, vb, pb);
1558 * If streamon has been called, and we haven't yet called
1559 * start_streaming() since not enough buffers were queued, and
1560 * we now have reached the minimum number of queued buffers,
1561 * then we can finally call start_streaming().
1563 if (q->streaming && !q->start_streaming_called &&
1564 q->queued_count >= q->min_buffers_needed) {
1565 ret = vb2_start_streaming(q);
1570 dprintk(1, "qbuf of buffer %d succeeded\n", vb->index);
1573 EXPORT_SYMBOL_GPL(vb2_core_qbuf);
1576 * __vb2_wait_for_done_vb() - wait for a buffer to become available
1579 * Will sleep if required for nonblocking == false.
1581 static int __vb2_wait_for_done_vb(struct vb2_queue *q, int nonblocking)
1584 * All operations on vb_done_list are performed under done_lock
1585 * spinlock protection. However, buffers may be removed from
1586 * it and returned to userspace only while holding both driver's
1587 * lock and the done_lock spinlock. Thus we can be sure that as
1588 * long as we hold the driver's lock, the list will remain not
1589 * empty if list_empty() check succeeds.
1595 if (!q->streaming) {
1596 dprintk(1, "streaming off, will not wait for buffers\n");
1601 dprintk(1, "Queue in error state, will not wait for buffers\n");
1605 if (q->last_buffer_dequeued) {
1606 dprintk(3, "last buffer dequeued already, will not wait for buffers\n");
1610 if (!list_empty(&q->done_list)) {
1612 * Found a buffer that we were waiting for.
1618 dprintk(1, "nonblocking and no buffers to dequeue, "
1624 * We are streaming and blocking, wait for another buffer to
1625 * become ready or for streamoff. Driver's lock is released to
1626 * allow streamoff or qbuf to be called while waiting.
1628 call_void_qop(q, wait_prepare, q);
1631 * All locks have been released, it is safe to sleep now.
1633 dprintk(3, "will sleep waiting for buffers\n");
1634 ret = wait_event_interruptible(q->done_wq,
1635 !list_empty(&q->done_list) || !q->streaming ||
1639 * We need to reevaluate both conditions again after reacquiring
1640 * the locks or return an error if one occurred.
1642 call_void_qop(q, wait_finish, q);
1644 dprintk(1, "sleep was interrupted\n");
1652 * __vb2_get_done_vb() - get a buffer ready for dequeuing
1654 * Will sleep if required for nonblocking == false.
1656 static int __vb2_get_done_vb(struct vb2_queue *q, struct vb2_buffer **vb,
1657 void *pb, int nonblocking)
1659 unsigned long flags;
1663 * Wait for at least one buffer to become available on the done_list.
1665 ret = __vb2_wait_for_done_vb(q, nonblocking);
1670 * Driver's lock has been held since we last verified that done_list
1671 * is not empty, so no need for another list_empty(done_list) check.
1673 spin_lock_irqsave(&q->done_lock, flags);
1674 *vb = list_first_entry(&q->done_list, struct vb2_buffer, done_entry);
1676 * Only remove the buffer from done_list if all planes can be
1677 * handled. Some cases such as V4L2 file I/O and DVB have pb
1678 * == NULL; skip the check then as there's nothing to verify.
1681 ret = call_bufop(q, verify_planes_array, *vb, pb);
1683 list_del(&(*vb)->done_entry);
1684 spin_unlock_irqrestore(&q->done_lock, flags);
1690 * vb2_wait_for_all_buffers() - wait until all buffers are given back to vb2
1691 * @q: videobuf2 queue
1693 * This function will wait until all buffers that have been given to the driver
1694 * by buf_queue() are given back to vb2 with vb2_buffer_done(). It doesn't call
1695 * wait_prepare, wait_finish pair. It is intended to be called with all locks
1696 * taken, for example from stop_streaming() callback.
1698 int vb2_wait_for_all_buffers(struct vb2_queue *q)
1700 if (!q->streaming) {
1701 dprintk(1, "streaming off, will not wait for buffers\n");
1705 if (q->start_streaming_called)
1706 wait_event(q->done_wq, !atomic_read(&q->owned_by_drv_count));
1709 EXPORT_SYMBOL_GPL(vb2_wait_for_all_buffers);
1712 * __vb2_dqbuf() - bring back the buffer to the DEQUEUED state
1714 static void __vb2_dqbuf(struct vb2_buffer *vb)
1716 struct vb2_queue *q = vb->vb2_queue;
1719 /* nothing to do if the buffer is already dequeued */
1720 if (vb->state == VB2_BUF_STATE_DEQUEUED)
1723 vb->state = VB2_BUF_STATE_DEQUEUED;
1725 /* unmap DMABUF buffer */
1726 if (q->memory == VB2_MEMORY_DMABUF)
1727 for (i = 0; i < vb->num_planes; ++i) {
1728 if (!vb->planes[i].dbuf_mapped)
1730 call_void_memop(vb, unmap_dmabuf, vb->planes[i].mem_priv);
1731 vb->planes[i].dbuf_mapped = 0;
1736 * vb2_dqbuf() - Dequeue a buffer to the userspace
1737 * @q: videobuf2 queue
1738 * @pb: buffer structure passed from userspace to vidioc_dqbuf handler
1740 * @nonblocking: if true, this call will not sleep waiting for a buffer if no
1741 * buffers ready for dequeuing are present. Normally the driver
1742 * would be passing (file->f_flags & O_NONBLOCK) here
1744 * Should be called from vidioc_dqbuf ioctl handler of a driver.
1745 * The passed buffer should have been verified.
1747 * 1) calls buf_finish callback in the driver (if provided), in which
1748 * driver can perform any additional operations that may be required before
1749 * returning the buffer to userspace, such as cache sync,
1750 * 2) the buffer struct members are filled with relevant information for
1753 * The return values from this function are intended to be directly returned
1754 * from vidioc_dqbuf handler in driver.
1756 int vb2_core_dqbuf(struct vb2_queue *q, unsigned int *pindex, void *pb,
1759 struct vb2_buffer *vb = NULL;
1762 ret = __vb2_get_done_vb(q, &vb, pb, nonblocking);
1766 switch (vb->state) {
1767 case VB2_BUF_STATE_DONE:
1768 dprintk(3, "returning done buffer\n");
1770 case VB2_BUF_STATE_ERROR:
1771 dprintk(3, "returning done buffer with errors\n");
1774 dprintk(1, "invalid buffer state\n");
1778 call_void_vb_qop(vb, buf_finish, vb);
1781 *pindex = vb->index;
1783 /* Fill buffer information for the userspace */
1785 call_void_bufop(q, fill_user_buffer, vb, pb);
1787 /* Remove from videobuf queue */
1788 list_del(&vb->queued_entry);
1791 trace_vb2_dqbuf(q, vb);
1793 /* go back to dequeued state */
1796 dprintk(1, "dqbuf of buffer %d, with state %d\n",
1797 vb->index, vb->state);
1802 EXPORT_SYMBOL_GPL(vb2_core_dqbuf);
1805 * __vb2_queue_cancel() - cancel and stop (pause) streaming
1807 * Removes all queued buffers from driver's queue and all buffers queued by
1808 * userspace from videobuf's queue. Returns to state after reqbufs.
1810 static void __vb2_queue_cancel(struct vb2_queue *q)
1815 * Tell driver to stop all transactions and release all queued
1818 if (q->start_streaming_called)
1819 call_void_qop(q, stop_streaming, q);
1822 * If you see this warning, then the driver isn't cleaning up properly
1823 * in stop_streaming(). See the stop_streaming() documentation in
1824 * videobuf2-core.h for more information how buffers should be returned
1825 * to vb2 in stop_streaming().
1827 if (WARN_ON(atomic_read(&q->owned_by_drv_count))) {
1828 for (i = 0; i < q->num_buffers; ++i)
1829 if (q->bufs[i]->state == VB2_BUF_STATE_ACTIVE)
1830 vb2_buffer_done(q->bufs[i], VB2_BUF_STATE_ERROR);
1831 /* Must be zero now */
1832 WARN_ON(atomic_read(&q->owned_by_drv_count));
1836 q->start_streaming_called = 0;
1837 q->queued_count = 0;
1841 * Remove all buffers from videobuf's list...
1843 INIT_LIST_HEAD(&q->queued_list);
1845 * ...and done list; userspace will not receive any buffers it
1846 * has not already dequeued before initiating cancel.
1848 INIT_LIST_HEAD(&q->done_list);
1849 atomic_set(&q->owned_by_drv_count, 0);
1850 wake_up_all(&q->done_wq);
1853 * Reinitialize all buffers for next use.
1854 * Make sure to call buf_finish for any queued buffers. Normally
1855 * that's done in dqbuf, but that's not going to happen when we
1856 * cancel the whole queue. Note: this code belongs here, not in
1857 * __vb2_dqbuf() since in vb2_core_dqbuf() there is a critical
1858 * call to __fill_user_buffer() after buf_finish(). That order can't
1859 * be changed, so we can't move the buf_finish() to __vb2_dqbuf().
1861 for (i = 0; i < q->num_buffers; ++i) {
1862 struct vb2_buffer *vb = q->bufs[i];
1864 if (vb->state != VB2_BUF_STATE_DEQUEUED) {
1865 vb->state = VB2_BUF_STATE_PREPARED;
1866 call_void_vb_qop(vb, buf_finish, vb);
1872 int vb2_core_streamon(struct vb2_queue *q, unsigned int type)
1876 if (type != q->type) {
1877 dprintk(1, "invalid stream type\n");
1882 dprintk(3, "already streaming\n");
1886 if (!q->num_buffers) {
1887 dprintk(1, "no buffers have been allocated\n");
1891 if (q->num_buffers < q->min_buffers_needed) {
1892 dprintk(1, "need at least %u allocated buffers\n",
1893 q->min_buffers_needed);
1898 * Tell driver to start streaming provided sufficient buffers
1901 if (q->queued_count >= q->min_buffers_needed) {
1902 ret = v4l_vb2q_enable_media_source(q);
1905 ret = vb2_start_streaming(q);
1907 __vb2_queue_cancel(q);
1914 dprintk(3, "successful\n");
1917 EXPORT_SYMBOL_GPL(vb2_core_streamon);
1920 * vb2_queue_error() - signal a fatal error on the queue
1921 * @q: videobuf2 queue
1923 * Flag that a fatal unrecoverable error has occurred and wake up all processes
1924 * waiting on the queue. Polling will now set POLLERR and queuing and dequeuing
1925 * buffers will return -EIO.
1927 * The error flag will be cleared when cancelling the queue, either from
1928 * vb2_streamoff or vb2_queue_release. Drivers should thus not call this
1929 * function before starting the stream, otherwise the error flag will remain set
1930 * until the queue is released when closing the device node.
1932 void vb2_queue_error(struct vb2_queue *q)
1936 wake_up_all(&q->done_wq);
1938 EXPORT_SYMBOL_GPL(vb2_queue_error);
1940 int vb2_core_streamoff(struct vb2_queue *q, unsigned int type)
1942 if (type != q->type) {
1943 dprintk(1, "invalid stream type\n");
1948 * Cancel will pause streaming and remove all buffers from the driver
1949 * and videobuf, effectively returning control over them to userspace.
1951 * Note that we do this even if q->streaming == 0: if you prepare or
1952 * queue buffers, and then call streamoff without ever having called
1953 * streamon, you would still expect those buffers to be returned to
1954 * their normal dequeued state.
1956 __vb2_queue_cancel(q);
1957 q->waiting_for_buffers = !q->is_output;
1958 q->last_buffer_dequeued = false;
1960 dprintk(3, "successful\n");
1963 EXPORT_SYMBOL_GPL(vb2_core_streamoff);
1966 * __find_plane_by_offset() - find plane associated with the given offset off
1968 static int __find_plane_by_offset(struct vb2_queue *q, unsigned long off,
1969 unsigned int *_buffer, unsigned int *_plane)
1971 struct vb2_buffer *vb;
1972 unsigned int buffer, plane;
1975 * Go over all buffers and their planes, comparing the given offset
1976 * with an offset assigned to each plane. If a match is found,
1977 * return its buffer and plane numbers.
1979 for (buffer = 0; buffer < q->num_buffers; ++buffer) {
1980 vb = q->bufs[buffer];
1982 for (plane = 0; plane < vb->num_planes; ++plane) {
1983 if (vb->planes[plane].m.offset == off) {
1995 * vb2_core_expbuf() - Export a buffer as a file descriptor
1996 * @q: videobuf2 queue
1997 * @fd: file descriptor associated with DMABUF (set by driver) *
1998 * @type: buffer type
1999 * @index: id number of the buffer
2000 * @plane: index of the plane to be exported, 0 for single plane queues
2001 * @flags: flags for newly created file, currently only O_CLOEXEC is
2002 * supported, refer to manual of open syscall for more details
2004 * The return values from this function are intended to be directly returned
2005 * from vidioc_expbuf handler in driver.
2007 int vb2_core_expbuf(struct vb2_queue *q, int *fd, unsigned int type,
2008 unsigned int index, unsigned int plane, unsigned int flags)
2010 struct vb2_buffer *vb = NULL;
2011 struct vb2_plane *vb_plane;
2013 struct dma_buf *dbuf;
2015 if (q->memory != VB2_MEMORY_MMAP) {
2016 dprintk(1, "queue is not currently set up for mmap\n");
2020 if (!q->mem_ops->get_dmabuf) {
2021 dprintk(1, "queue does not support DMA buffer exporting\n");
2025 if (flags & ~(O_CLOEXEC | O_ACCMODE)) {
2026 dprintk(1, "queue does support only O_CLOEXEC and access mode flags\n");
2030 if (type != q->type) {
2031 dprintk(1, "invalid buffer type\n");
2035 if (index >= q->num_buffers) {
2036 dprintk(1, "buffer index out of range\n");
2040 vb = q->bufs[index];
2042 if (plane >= vb->num_planes) {
2043 dprintk(1, "buffer plane out of range\n");
2047 if (vb2_fileio_is_active(q)) {
2048 dprintk(1, "expbuf: file io in progress\n");
2052 vb_plane = &vb->planes[plane];
2054 dbuf = call_ptr_memop(vb, get_dmabuf, vb_plane->mem_priv,
2056 if (IS_ERR_OR_NULL(dbuf)) {
2057 dprintk(1, "failed to export buffer %d, plane %d\n",
2062 ret = dma_buf_fd(dbuf, flags & ~O_ACCMODE);
2064 dprintk(3, "buffer %d, plane %d failed to export (%d)\n",
2070 dprintk(3, "buffer %d, plane %d exported as %d descriptor\n",
2076 EXPORT_SYMBOL_GPL(vb2_core_expbuf);
2079 * vb2_mmap() - map video buffers into application address space
2080 * @q: videobuf2 queue
2081 * @vma: vma passed to the mmap file operation handler in the driver
2083 * Should be called from mmap file operation handler of a driver.
2084 * This function maps one plane of one of the available video buffers to
2085 * userspace. To map whole video memory allocated on reqbufs, this function
2086 * has to be called once per each plane per each buffer previously allocated.
2088 * When the userspace application calls mmap, it passes to it an offset returned
2089 * to it earlier by the means of vidioc_querybuf handler. That offset acts as
2090 * a "cookie", which is then used to identify the plane to be mapped.
2091 * This function finds a plane with a matching offset and a mapping is performed
2092 * by the means of a provided memory operation.
2094 * The return values from this function are intended to be directly returned
2095 * from the mmap handler in driver.
2097 int vb2_mmap(struct vb2_queue *q, struct vm_area_struct *vma)
2099 unsigned long off = vma->vm_pgoff << PAGE_SHIFT;
2100 struct vb2_buffer *vb;
2101 unsigned int buffer = 0, plane = 0;
2103 unsigned long length;
2105 if (q->memory != VB2_MEMORY_MMAP) {
2106 dprintk(1, "queue is not currently set up for mmap\n");
2111 * Check memory area access mode.
2113 if (!(vma->vm_flags & VM_SHARED)) {
2114 dprintk(1, "invalid vma flags, VM_SHARED needed\n");
2118 if (!(vma->vm_flags & VM_WRITE)) {
2119 dprintk(1, "invalid vma flags, VM_WRITE needed\n");
2123 if (!(vma->vm_flags & VM_READ)) {
2124 dprintk(1, "invalid vma flags, VM_READ needed\n");
2128 if (vb2_fileio_is_active(q)) {
2129 dprintk(1, "mmap: file io in progress\n");
2134 * Find the plane corresponding to the offset passed by userspace.
2136 ret = __find_plane_by_offset(q, off, &buffer, &plane);
2140 vb = q->bufs[buffer];
2143 * MMAP requires page_aligned buffers.
2144 * The buffer length was page_aligned at __vb2_buf_mem_alloc(),
2145 * so, we need to do the same here.
2147 length = PAGE_ALIGN(vb->planes[plane].length);
2148 if (length < (vma->vm_end - vma->vm_start)) {
2150 "MMAP invalid, as it would overflow buffer length\n");
2154 mutex_lock(&q->mmap_lock);
2155 ret = call_memop(vb, mmap, vb->planes[plane].mem_priv, vma);
2156 mutex_unlock(&q->mmap_lock);
2160 dprintk(3, "buffer %d, plane %d successfully mapped\n", buffer, plane);
2163 EXPORT_SYMBOL_GPL(vb2_mmap);
2166 unsigned long vb2_get_unmapped_area(struct vb2_queue *q,
2169 unsigned long pgoff,
2170 unsigned long flags)
2172 unsigned long off = pgoff << PAGE_SHIFT;
2173 struct vb2_buffer *vb;
2174 unsigned int buffer, plane;
2178 if (q->memory != VB2_MEMORY_MMAP) {
2179 dprintk(1, "queue is not currently set up for mmap\n");
2184 * Find the plane corresponding to the offset passed by userspace.
2186 ret = __find_plane_by_offset(q, off, &buffer, &plane);
2190 vb = q->bufs[buffer];
2192 vaddr = vb2_plane_vaddr(vb, plane);
2193 return vaddr ? (unsigned long)vaddr : -EINVAL;
2195 EXPORT_SYMBOL_GPL(vb2_get_unmapped_area);
2199 * vb2_core_queue_init() - initialize a videobuf2 queue
2200 * @q: videobuf2 queue; this structure should be allocated in driver
2202 * The vb2_queue structure should be allocated by the driver. The driver is
2203 * responsible of clearing it's content and setting initial values for some
2204 * required entries before calling this function.
2205 * q->ops, q->mem_ops, q->type and q->io_modes are mandatory. Please refer
2206 * to the struct vb2_queue description in include/media/videobuf2-core.h
2207 * for more information.
2209 int vb2_core_queue_init(struct vb2_queue *q)
2216 WARN_ON(!q->mem_ops) ||
2217 WARN_ON(!q->type) ||
2218 WARN_ON(!q->io_modes) ||
2219 WARN_ON(!q->ops->queue_setup) ||
2220 WARN_ON(!q->ops->buf_queue))
2223 INIT_LIST_HEAD(&q->queued_list);
2224 INIT_LIST_HEAD(&q->done_list);
2225 spin_lock_init(&q->done_lock);
2226 mutex_init(&q->mmap_lock);
2227 init_waitqueue_head(&q->done_wq);
2229 if (q->buf_struct_size == 0)
2230 q->buf_struct_size = sizeof(struct vb2_buffer);
2234 EXPORT_SYMBOL_GPL(vb2_core_queue_init);
2236 static int __vb2_init_fileio(struct vb2_queue *q, int read);
2237 static int __vb2_cleanup_fileio(struct vb2_queue *q);
2239 * vb2_core_queue_release() - stop streaming, release the queue and free memory
2240 * @q: videobuf2 queue
2242 * This function stops streaming and performs necessary clean ups, including
2243 * freeing video buffer memory. The driver is responsible for freeing
2244 * the vb2_queue structure itself.
2246 void vb2_core_queue_release(struct vb2_queue *q)
2248 __vb2_cleanup_fileio(q);
2249 __vb2_queue_cancel(q);
2250 mutex_lock(&q->mmap_lock);
2251 __vb2_queue_free(q, q->num_buffers);
2252 mutex_unlock(&q->mmap_lock);
2254 EXPORT_SYMBOL_GPL(vb2_core_queue_release);
2257 * vb2_core_poll() - implements poll userspace operation
2258 * @q: videobuf2 queue
2259 * @file: file argument passed to the poll file operation handler
2260 * @wait: wait argument passed to the poll file operation handler
2262 * This function implements poll file operation handler for a driver.
2263 * For CAPTURE queues, if a buffer is ready to be dequeued, the userspace will
2264 * be informed that the file descriptor of a video device is available for
2266 * For OUTPUT queues, if a buffer is ready to be dequeued, the file descriptor
2267 * will be reported as available for writing.
2269 * The return values from this function are intended to be directly returned
2270 * from poll handler in driver.
2272 unsigned int vb2_core_poll(struct vb2_queue *q, struct file *file,
2275 unsigned long req_events = poll_requested_events(wait);
2276 struct vb2_buffer *vb = NULL;
2277 unsigned long flags;
2279 if (!q->is_output && !(req_events & (POLLIN | POLLRDNORM)))
2281 if (q->is_output && !(req_events & (POLLOUT | POLLWRNORM)))
2285 * Start file I/O emulator only if streaming API has not been used yet.
2287 if (q->num_buffers == 0 && !vb2_fileio_is_active(q)) {
2288 if (!q->is_output && (q->io_modes & VB2_READ) &&
2289 (req_events & (POLLIN | POLLRDNORM))) {
2290 if (__vb2_init_fileio(q, 1))
2293 if (q->is_output && (q->io_modes & VB2_WRITE) &&
2294 (req_events & (POLLOUT | POLLWRNORM))) {
2295 if (__vb2_init_fileio(q, 0))
2298 * Write to OUTPUT queue can be done immediately.
2300 return POLLOUT | POLLWRNORM;
2305 * There is nothing to wait for if the queue isn't streaming, or if the
2306 * error flag is set.
2308 if (!vb2_is_streaming(q) || q->error)
2312 * If this quirk is set and QBUF hasn't been called yet then
2313 * return POLLERR as well. This only affects capture queues, output
2314 * queues will always initialize waiting_for_buffers to false.
2315 * This quirk is set by V4L2 for backwards compatibility reasons.
2317 if (q->quirk_poll_must_check_waiting_for_buffers &&
2318 q->waiting_for_buffers && (req_events & (POLLIN | POLLRDNORM)))
2322 * For output streams you can call write() as long as there are fewer
2323 * buffers queued than there are buffers available.
2325 if (q->is_output && q->fileio && q->queued_count < q->num_buffers)
2326 return POLLOUT | POLLWRNORM;
2328 if (list_empty(&q->done_list)) {
2330 * If the last buffer was dequeued from a capture queue,
2331 * return immediately. DQBUF will return -EPIPE.
2333 if (q->last_buffer_dequeued)
2334 return POLLIN | POLLRDNORM;
2336 poll_wait(file, &q->done_wq, wait);
2340 * Take first buffer available for dequeuing.
2342 spin_lock_irqsave(&q->done_lock, flags);
2343 if (!list_empty(&q->done_list))
2344 vb = list_first_entry(&q->done_list, struct vb2_buffer,
2346 spin_unlock_irqrestore(&q->done_lock, flags);
2348 if (vb && (vb->state == VB2_BUF_STATE_DONE
2349 || vb->state == VB2_BUF_STATE_ERROR)) {
2350 return (q->is_output) ?
2351 POLLOUT | POLLWRNORM :
2352 POLLIN | POLLRDNORM;
2356 EXPORT_SYMBOL_GPL(vb2_core_poll);
2359 * struct vb2_fileio_buf - buffer context used by file io emulator
2361 * vb2 provides a compatibility layer and emulator of file io (read and
2362 * write) calls on top of streaming API. This structure is used for
2363 * tracking context related to the buffers.
2365 struct vb2_fileio_buf {
2369 unsigned int queued:1;
2373 * struct vb2_fileio_data - queue context used by file io emulator
2375 * @cur_index: the index of the buffer currently being read from or
2376 * written to. If equal to q->num_buffers then a new buffer
2378 * @initial_index: in the read() case all buffers are queued up immediately
2379 * in __vb2_init_fileio() and __vb2_perform_fileio() just cycles
2380 * buffers. However, in the write() case no buffers are initially
2381 * queued, instead whenever a buffer is full it is queued up by
2382 * __vb2_perform_fileio(). Only once all available buffers have
2383 * been queued up will __vb2_perform_fileio() start to dequeue
2384 * buffers. This means that initially __vb2_perform_fileio()
2385 * needs to know what buffer index to use when it is queuing up
2386 * the buffers for the first time. That initial index is stored
2387 * in this field. Once it is equal to q->num_buffers all
2388 * available buffers have been queued and __vb2_perform_fileio()
2389 * should start the normal dequeue/queue cycle.
2391 * vb2 provides a compatibility layer and emulator of file io (read and
2392 * write) calls on top of streaming API. For proper operation it required
2393 * this structure to save the driver state between each call of the read
2394 * or write function.
2396 struct vb2_fileio_data {
2399 unsigned int memory;
2400 struct vb2_fileio_buf bufs[VB2_MAX_FRAME];
2401 unsigned int cur_index;
2402 unsigned int initial_index;
2403 unsigned int q_count;
2404 unsigned int dq_count;
2405 unsigned read_once:1;
2406 unsigned write_immediately:1;
2410 * __vb2_init_fileio() - initialize file io emulator
2411 * @q: videobuf2 queue
2412 * @read: mode selector (1 means read, 0 means write)
2414 static int __vb2_init_fileio(struct vb2_queue *q, int read)
2416 struct vb2_fileio_data *fileio;
2418 unsigned int count = 0;
2423 if (WARN_ON((read && !(q->io_modes & VB2_READ)) ||
2424 (!read && !(q->io_modes & VB2_WRITE))))
2428 * Check if device supports mapping buffers to kernel virtual space.
2430 if (!q->mem_ops->vaddr)
2434 * Check if streaming api has not been already activated.
2436 if (q->streaming || q->num_buffers > 0)
2440 * Start with count 1, driver can increase it in queue_setup()
2444 dprintk(3, "setting up file io: mode %s, count %d, read_once %d, write_immediately %d\n",
2445 (read) ? "read" : "write", count, q->fileio_read_once,
2446 q->fileio_write_immediately);
2448 fileio = kzalloc(sizeof(*fileio), GFP_KERNEL);
2452 fileio->read_once = q->fileio_read_once;
2453 fileio->write_immediately = q->fileio_write_immediately;
2456 * Request buffers and use MMAP type to force driver
2457 * to allocate buffers by itself.
2459 fileio->count = count;
2460 fileio->memory = VB2_MEMORY_MMAP;
2461 fileio->type = q->type;
2463 ret = vb2_core_reqbufs(q, fileio->memory, &fileio->count);
2468 * Check if plane_count is correct
2469 * (multiplane buffers are not supported).
2471 if (q->bufs[0]->num_planes != 1) {
2477 * Get kernel address of each buffer.
2479 for (i = 0; i < q->num_buffers; i++) {
2480 fileio->bufs[i].vaddr = vb2_plane_vaddr(q->bufs[i], 0);
2481 if (fileio->bufs[i].vaddr == NULL) {
2485 fileio->bufs[i].size = vb2_plane_size(q->bufs[i], 0);
2489 * Read mode requires pre queuing of all buffers.
2493 * Queue all buffers.
2495 for (i = 0; i < q->num_buffers; i++) {
2496 ret = vb2_core_qbuf(q, i, NULL);
2499 fileio->bufs[i].queued = 1;
2502 * All buffers have been queued, so mark that by setting
2503 * initial_index to q->num_buffers
2505 fileio->initial_index = q->num_buffers;
2506 fileio->cur_index = q->num_buffers;
2512 ret = vb2_core_streamon(q, q->type);
2520 vb2_core_reqbufs(q, fileio->memory, &fileio->count);
2529 * __vb2_cleanup_fileio() - free resourced used by file io emulator
2530 * @q: videobuf2 queue
2532 static int __vb2_cleanup_fileio(struct vb2_queue *q)
2534 struct vb2_fileio_data *fileio = q->fileio;
2537 vb2_core_streamoff(q, q->type);
2540 vb2_core_reqbufs(q, fileio->memory, &fileio->count);
2542 dprintk(3, "file io emulator closed\n");
2548 * __vb2_perform_fileio() - perform a single file io (read or write) operation
2549 * @q: videobuf2 queue
2550 * @data: pointed to target userspace buffer
2551 * @count: number of bytes to read or write
2552 * @ppos: file handle position tracking pointer
2553 * @nonblock: mode selector (1 means blocking calls, 0 means nonblocking)
2554 * @read: access mode selector (1 means read, 0 means write)
2556 static size_t __vb2_perform_fileio(struct vb2_queue *q, char __user *data, size_t count,
2557 loff_t *ppos, int nonblock, int read)
2559 struct vb2_fileio_data *fileio;
2560 struct vb2_fileio_buf *buf;
2561 bool is_multiplanar = q->is_multiplanar;
2563 * When using write() to write data to an output video node the vb2 core
2564 * should copy timestamps if V4L2_BUF_FLAG_TIMESTAMP_COPY is set. Nobody
2565 * else is able to provide this information with the write() operation.
2567 bool copy_timestamp = !read && q->copy_timestamp;
2571 dprintk(3, "mode %s, offset %ld, count %zd, %sblocking\n",
2572 read ? "read" : "write", (long)*ppos, count,
2573 nonblock ? "non" : "");
2579 * Initialize emulator on first call.
2581 if (!vb2_fileio_is_active(q)) {
2582 ret = __vb2_init_fileio(q, read);
2583 dprintk(3, "vb2_init_fileio result: %d\n", ret);
2590 * Check if we need to dequeue the buffer.
2592 index = fileio->cur_index;
2593 if (index >= q->num_buffers) {
2594 struct vb2_buffer *b;
2597 * Call vb2_dqbuf to get buffer back.
2599 ret = vb2_core_dqbuf(q, &index, NULL, nonblock);
2600 dprintk(5, "vb2_dqbuf result: %d\n", ret);
2603 fileio->dq_count += 1;
2605 fileio->cur_index = index;
2606 buf = &fileio->bufs[index];
2610 * Get number of bytes filled by the driver
2614 buf->size = read ? vb2_get_plane_payload(q->bufs[index], 0)
2615 : vb2_plane_size(q->bufs[index], 0);
2616 /* Compensate for data_offset on read in the multiplanar case. */
2617 if (is_multiplanar && read &&
2618 b->planes[0].data_offset < buf->size) {
2619 buf->pos = b->planes[0].data_offset;
2620 buf->size -= buf->pos;
2623 buf = &fileio->bufs[index];
2627 * Limit count on last few bytes of the buffer.
2629 if (buf->pos + count > buf->size) {
2630 count = buf->size - buf->pos;
2631 dprintk(5, "reducing read count: %zd\n", count);
2635 * Transfer data to userspace.
2637 dprintk(3, "copying %zd bytes - buffer %d, offset %u\n",
2638 count, index, buf->pos);
2640 ret = copy_to_user(data, buf->vaddr + buf->pos, count);
2642 ret = copy_from_user(buf->vaddr + buf->pos, data, count);
2644 dprintk(3, "error copying data\n");
2655 * Queue next buffer if required.
2657 if (buf->pos == buf->size || (!read && fileio->write_immediately)) {
2658 struct vb2_buffer *b = q->bufs[index];
2661 * Check if this is the last buffer to read.
2663 if (read && fileio->read_once && fileio->dq_count == 1) {
2664 dprintk(3, "read limit reached\n");
2665 return __vb2_cleanup_fileio(q);
2669 * Call vb2_qbuf and give buffer to the driver.
2671 b->planes[0].bytesused = buf->pos;
2674 b->timestamp = ktime_get_ns();
2675 ret = vb2_core_qbuf(q, index, NULL);
2676 dprintk(5, "vb2_dbuf result: %d\n", ret);
2681 * Buffer has been queued, update the status
2685 buf->size = vb2_plane_size(q->bufs[index], 0);
2686 fileio->q_count += 1;
2688 * If we are queuing up buffers for the first time, then
2689 * increase initial_index by one.
2691 if (fileio->initial_index < q->num_buffers)
2692 fileio->initial_index++;
2694 * The next buffer to use is either a buffer that's going to be
2695 * queued for the first time (initial_index < q->num_buffers)
2696 * or it is equal to q->num_buffers, meaning that the next
2697 * time we need to dequeue a buffer since we've now queued up
2698 * all the 'first time' buffers.
2700 fileio->cur_index = fileio->initial_index;
2704 * Return proper number of bytes processed.
2711 size_t vb2_read(struct vb2_queue *q, char __user *data, size_t count,
2712 loff_t *ppos, int nonblocking)
2714 return __vb2_perform_fileio(q, data, count, ppos, nonblocking, 1);
2716 EXPORT_SYMBOL_GPL(vb2_read);
2718 size_t vb2_write(struct vb2_queue *q, const char __user *data, size_t count,
2719 loff_t *ppos, int nonblocking)
2721 return __vb2_perform_fileio(q, (char __user *) data, count,
2722 ppos, nonblocking, 0);
2724 EXPORT_SYMBOL_GPL(vb2_write);
2726 struct vb2_threadio_data {
2727 struct task_struct *thread;
2733 static int vb2_thread(void *data)
2735 struct vb2_queue *q = data;
2736 struct vb2_threadio_data *threadio = q->threadio;
2737 bool copy_timestamp = false;
2738 unsigned prequeue = 0;
2743 prequeue = q->num_buffers;
2744 copy_timestamp = q->copy_timestamp;
2750 struct vb2_buffer *vb;
2753 * Call vb2_dqbuf to get buffer back.
2756 vb = q->bufs[index++];
2759 call_void_qop(q, wait_finish, q);
2760 if (!threadio->stop)
2761 ret = vb2_core_dqbuf(q, &index, NULL, 0);
2762 call_void_qop(q, wait_prepare, q);
2763 dprintk(5, "file io: vb2_dqbuf result: %d\n", ret);
2765 vb = q->bufs[index];
2767 if (ret || threadio->stop)
2771 if (vb->state != VB2_BUF_STATE_ERROR)
2772 if (threadio->fnc(vb, threadio->priv))
2774 call_void_qop(q, wait_finish, q);
2776 vb->timestamp = ktime_get_ns();;
2777 if (!threadio->stop)
2778 ret = vb2_core_qbuf(q, vb->index, NULL);
2779 call_void_qop(q, wait_prepare, q);
2780 if (ret || threadio->stop)
2784 /* Hmm, linux becomes *very* unhappy without this ... */
2785 while (!kthread_should_stop()) {
2786 set_current_state(TASK_INTERRUPTIBLE);
2793 * This function should not be used for anything else but the videobuf2-dvb
2794 * support. If you think you have another good use-case for this, then please
2795 * contact the linux-media mailinglist first.
2797 int vb2_thread_start(struct vb2_queue *q, vb2_thread_fnc fnc, void *priv,
2798 const char *thread_name)
2800 struct vb2_threadio_data *threadio;
2807 if (WARN_ON(q->fileio))
2810 threadio = kzalloc(sizeof(*threadio), GFP_KERNEL);
2811 if (threadio == NULL)
2813 threadio->fnc = fnc;
2814 threadio->priv = priv;
2816 ret = __vb2_init_fileio(q, !q->is_output);
2817 dprintk(3, "file io: vb2_init_fileio result: %d\n", ret);
2820 q->threadio = threadio;
2821 threadio->thread = kthread_run(vb2_thread, q, "vb2-%s", thread_name);
2822 if (IS_ERR(threadio->thread)) {
2823 ret = PTR_ERR(threadio->thread);
2824 threadio->thread = NULL;
2830 __vb2_cleanup_fileio(q);
2835 EXPORT_SYMBOL_GPL(vb2_thread_start);
2837 int vb2_thread_stop(struct vb2_queue *q)
2839 struct vb2_threadio_data *threadio = q->threadio;
2842 if (threadio == NULL)
2844 threadio->stop = true;
2845 /* Wake up all pending sleeps in the thread */
2847 err = kthread_stop(threadio->thread);
2848 __vb2_cleanup_fileio(q);
2849 threadio->thread = NULL;
2854 EXPORT_SYMBOL_GPL(vb2_thread_stop);
2856 MODULE_DESCRIPTION("Media buffer core framework");
2857 MODULE_AUTHOR("Pawel Osciak <pawel@osciak.com>, Marek Szyprowski");
2858 MODULE_LICENSE("GPL");