summaryrefslogtreecommitdiff
path: root/include/media/videobuf2-core.h
blob: b6546db670cae50d27c66bfda5f0ab0bedd28d40 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
/*
 * videobuf2-core.h - Video Buffer 2 Core Framework
 *
 * Copyright (C) 2010 Samsung Electronics
 *
 * Author: Pawel Osciak <pawel@osciak.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation.
 */
#ifndef _MEDIA_VIDEOBUF2_CORE_H
#define _MEDIA_VIDEOBUF2_CORE_H

#include <linux/mm_types.h>
#include <linux/mutex.h>
#include <linux/poll.h>
#include <linux/dma-buf.h>

#define VB2_MAX_FRAME	(32)
#define VB2_MAX_PLANES	(8)

enum vb2_memory {
	VB2_MEMORY_UNKNOWN	= 0,
	VB2_MEMORY_MMAP		= 1,
	VB2_MEMORY_USERPTR	= 2,
	VB2_MEMORY_DMABUF	= 4,
};

struct vb2_fileio_data;
struct vb2_threadio_data;

/**
 * struct vb2_mem_ops - memory handling/memory allocator operations
 * @alloc:	allocate video memory and, optionally, allocator private data,
 *		return ERR_PTR() on failure or a pointer to allocator private,
 *		per-buffer data on success; the returned private structure
 *		will then be passed as buf_priv argument to other ops in this
 *		structure. Additional gfp_flags to use when allocating the
 *		are also passed to this operation. These flags are from the
 *		gfp_flags field of vb2_queue.
 * @put:	inform the allocator that the buffer will no longer be used;
 *		usually will result in the allocator freeing the buffer (if
 *		no other users of this buffer are present); the buf_priv
 *		argument is the allocator private per-buffer structure
 *		previously returned from the alloc callback.
 * @get_dmabuf: acquire userspace memory for a hardware operation; used for
 *		 DMABUF memory types.
 * @get_userptr: acquire userspace memory for a hardware operation; used for
 *		 USERPTR memory types; vaddr is the address passed to the
 *		 videobuf layer when queuing a video buffer of USERPTR type;
 *		 should return an allocator private per-buffer structure
 *		 associated with the buffer on success, ERR_PTR() on failure;
 *		 the returned private structure will then be passed as buf_priv
 *		 argument to other ops in this structure.
 * @put_userptr: inform the allocator that a USERPTR buffer will no longer
 *		 be used.
 * @attach_dmabuf: attach a shared struct dma_buf for a hardware operation;
 *		   used for DMABUF memory types; dev is the alloc device
 *		   dbuf is the shared dma_buf; returns ERR_PTR() on failure;
 *		   allocator private per-buffer structure on success;
 *		   this needs to be used for further accesses to the buffer.
 * @detach_dmabuf: inform the exporter of the buffer that the current DMABUF
 *		   buffer is no longer used; the buf_priv argument is the
 *		   allocator private per-buffer structure previously returned
 *		   from the attach_dmabuf callback.
 * @map_dmabuf: request for access to the dmabuf from allocator; the allocator
 *		of dmabuf is informed that this driver is going to use the
 *		dmabuf.
 * @unmap_dmabuf: releases access control to the dmabuf - allocator is notified
 *		  that this driver is done using the dmabuf for now.
 * @prepare:	called every time the buffer is passed from userspace to the
 *		driver, useful for cache synchronisation, optional.
 * @finish:	called every time the buffer is passed back from the driver
 *		to the userspace, also optional.
 * @vaddr:	return a kernel virtual address to a given memory buffer
 *		associated with the passed private structure or NULL if no
 *		such mapping exists.
 * @cookie:	return allocator specific cookie for a given memory buffer
 *		associated with the passed private structure or NULL if not
 *		available.
 * @num_users:	return the current number of users of a memory buffer;
 *		return 1 if the videobuf layer (or actually the driver using
 *		it) is the only user.
 * @mmap:	setup a userspace mapping for a given memory buffer under
 *		the provided virtual memory region.
 *
 * Those operations are used by the videobuf2 core to implement the memory
 * handling/memory allocators for each type of supported streaming I/O method.
 *
 * .. note::
 *    #) Required ops for USERPTR types: get_userptr, put_userptr.
 *
 *    #) Required ops for MMAP types: alloc, put, num_users, mmap.
 *
 *    #) Required ops for read/write access types: alloc, put, num_users, vaddr.
 *
 *    #) Required ops for DMABUF types: attach_dmabuf, detach_dmabuf, map_dmabuf, unmap_dmabuf.
 */
struct vb2_mem_ops {
	void		*(*alloc)(struct device *dev, unsigned long attrs,
				  unsigned long size, enum dma_data_direction dma_dir,
				  gfp_t gfp_flags);
	void		(*put)(void *buf_priv);
	struct dma_buf *(*get_dmabuf)(void *buf_priv, unsigned long flags);

	void		*(*get_userptr)(struct device *dev, unsigned long vaddr,
					unsigned long size,
					enum dma_data_direction dma_dir);
	void		(*put_userptr)(void *buf_priv);

	void		(*prepare)(void *buf_priv);
	void		(*finish)(void *buf_priv);

	void		*(*attach_dmabuf)(struct device *dev, struct dma_buf *dbuf,
					  unsigned long size,
					  enum dma_data_direction dma_dir);
	void		(*detach_dmabuf)(void *buf_priv);
	int		(*map_dmabuf)(void *buf_priv);
	void		(*unmap_dmabuf)(void *buf_priv);

	void		*(*vaddr)(void *buf_priv);
	void		*(*cookie)(void *buf_priv);

	unsigned int	(*num_users)(void *buf_priv);

	int		(*mmap)(void *buf_priv, struct vm_area_struct *vma);
};

/**
 * struct vb2_plane - plane information
 * @mem_priv:	private data with this plane
 * @dbuf:	dma_buf - shared buffer object
 * @dbuf_mapped:	flag to show whether dbuf is mapped or not
 * @bytesused:	number of bytes occupied by data in the plane (payload)
 * @length:	size of this plane (NOT the payload) in bytes
 * @min_length:	minimum required size of this plane (NOT the payload) in bytes.
 *		@length is always greater or equal to @min_length.
 * @offset:	when memory in the associated struct vb2_buffer is
 *		VB2_MEMORY_MMAP, equals the offset from the start of
 *		the device memory for this plane (or is a "cookie" that
 *		should be passed to mmap() called on the video node)
 * @userptr:	when memory is VB2_MEMORY_USERPTR, a userspace pointer
 *		pointing to this plane
 * @fd:		when memory is VB2_MEMORY_DMABUF, a userspace file
 *		descriptor associated with this plane
 * @m:		Union with memtype-specific data (@offset, @userptr or
 *		@fd).
 * @data_offset:	offset in the plane to the start of data; usually 0,
 *		unless there is a header in front of the data
 * Should contain enough information to be able to cover all the fields
 * of struct v4l2_plane at videodev2.h
 */
struct vb2_plane {
	void			*mem_priv;
	struct dma_buf		*dbuf;
	unsigned int		dbuf_mapped;
	unsigned int		bytesused;
	unsigned int		length;
	unsigned int		min_length;
	union {
		unsigned int	offset;
		unsigned long	userptr;
		int		fd;
	} m;
	unsigned int		data_offset;
};

/**
 * enum vb2_io_modes - queue access methods
 * @VB2_MMAP:		driver supports MMAP with streaming API
 * @VB2_USERPTR:	driver supports USERPTR with streaming API
 * @VB2_READ:		driver supports read() style access
 * @VB2_WRITE:		driver supports write() style access
 * @VB2_DMABUF:		driver supports DMABUF with streaming API
 */
enum vb2_io_modes {
	VB2_MMAP	= (1 << 0),
	VB2_USERPTR	= (1 << 1),
	VB2_READ	= (1 << 2),
	VB2_WRITE	= (1 << 3),
	VB2_DMABUF	= (1 << 4),
};

/**
 * enum vb2_buffer_state - current video buffer state
 * @VB2_BUF_STATE_DEQUEUED:	buffer under userspace control
 * @VB2_BUF_STATE_PREPARING:	buffer is being prepared in videobuf
 * @VB2_BUF_STATE_PREPARED:	buffer prepared in videobuf and by the driver
 * @VB2_BUF_STATE_QUEUED:	buffer queued in videobuf, but not in driver
 * @VB2_BUF_STATE_REQUEUEING:	re-queue a buffer to the driver
 * @VB2_BUF_STATE_ACTIVE:	buffer queued in driver and possibly used
 *				in a hardware operation
 * @VB2_BUF_STATE_DONE:		buffer returned from driver to videobuf, but
 *				not yet dequeued to userspace
 * @VB2_BUF_STATE_ERROR:	same as above, but the operation on the buffer
 *				has ended with an error, which will be reported
 *				to the userspace when it is dequeued
 */
enum vb2_buffer_state {
	VB2_BUF_STATE_DEQUEUED,
	VB2_BUF_STATE_PREPARING,
	VB2_BUF_STATE_PREPARED,
	VB2_BUF_STATE_QUEUED,
	VB2_BUF_STATE_REQUEUEING,
	VB2_BUF_STATE_ACTIVE,
	VB2_BUF_STATE_DONE,
	VB2_BUF_STATE_ERROR,
};

struct vb2_queue;

/**
 * struct vb2_buffer - represents a video buffer
 * @vb2_queue:		the queue to which this driver belongs
 * @index:		id number of the buffer
 * @type:		buffer type
 * @memory:		the method, in which the actual data is passed
 * @num_planes:		number of planes in the buffer
 *			on an internal driver queue
 * @planes:		private per-plane information; do not change
 * @timestamp:		frame timestamp in ns
 */
struct vb2_buffer {
	struct vb2_queue	*vb2_queue;
	unsigned int		index;
	unsigned int		type;
	unsigned int		memory;
	unsigned int		num_planes;
	struct vb2_plane	planes[VB2_MAX_PLANES];
	u64			timestamp;

	/* private: internal use only
	 *
	 * state:		current buffer state; do not change
	 * queued_entry:	entry on the queued buffers list, which holds
	 *			all buffers queued from userspace
	 * done_entry:		entry on the list that stores all buffers ready
	 *			to be dequeued to userspace
	 */
	enum vb2_buffer_state	state;

	struct list_head	queued_entry;
	struct list_head	done_entry;
#ifdef CONFIG_VIDEO_ADV_DEBUG
	/*
	 * Counters for how often these buffer-related ops are
	 * called. Used to check for unbalanced ops.
	 */
	u32		cnt_mem_alloc;
	u32		cnt_mem_put;
	u32		cnt_mem_get_dmabuf;
	u32		cnt_mem_get_userptr;
	u32		cnt_mem_put_userptr;
	u32		cnt_mem_prepare;
	u32		cnt_mem_finish;
	u32		cnt_mem_attach_dmabuf;
	u32		cnt_mem_detach_dmabuf;
	u32		cnt_mem_map_dmabuf;
	u32		cnt_mem_unmap_dmabuf;
	u32		cnt_mem_vaddr;
	u32		cnt_mem_cookie;
	u32		cnt_mem_num_users;
	u32		cnt_mem_mmap;

	u32		cnt_buf_init;
	u32		cnt_buf_prepare;
	u32		cnt_buf_finish;
	u32		cnt_buf_cleanup;
	u32		cnt_buf_queue;

	/* This counts the number of calls to vb2_buffer_done() */
	u32		cnt_buf_done;
#endif
};

/**
 * struct vb2_ops - driver-specific callbacks
 *
 * @queue_setup:	called from %VIDIOC_REQBUFS and %VIDIOC_CREATE_BUFS
 *			handlers before memory allocation. It can be called
 *			twice: if the original number of requested buffers
 *			could not be allocated, then it will be called a
 *			second time with the actually allocated number of
 *			buffers to verify if that is OK.
 *			The driver should return the required number of buffers
 *			in \*num_buffers, the required number of planes per
 *			buffer in \*num_planes, the size of each plane should be
 *			set in the sizes\[\] array and optional per-plane
 *			allocator specific device in the alloc_devs\[\] array.
 *			When called from %VIDIOC_REQBUFS, \*num_planes == 0, the
 *			driver has to use the currently configured format to
 *			determine the plane sizes and \*num_buffers is the total
 *			number of buffers that are being allocated. When called
 *			from %VIDIOC_CREATE_BUFS, \*num_planes != 0 and it
 *			describes the requested number of planes and sizes\[\]
 *			contains the requested plane sizes. If either
 *			\*num_planes or the requested sizes are invalid callback
 *			must return %-EINVAL. In this case \*num_buffers are
 *			being allocated additionally to q->num_buffers.
 * @wait_prepare:	release any locks taken while calling vb2 functions;
 *			it is called before an ioctl needs to wait for a new
 *			buffer to arrive; required to avoid a deadlock in
 *			blocking access type.
 * @wait_finish:	reacquire all locks released in the previous callback;
 *			required to continue operation after sleeping while
 *			waiting for a new buffer to arrive.
 * @buf_init:		called once after allocating a buffer (in MMAP case)
 *			or after acquiring a new USERPTR buffer; drivers may
 *			perform additional buffer-related initialization;
 *			initialization failure (return != 0) will prevent
 *			queue setup from completing successfully; optional.
 * @buf_prepare:	called every time the buffer is queued from userspace
 *			and from the %VIDIOC_PREPARE_BUF ioctl; drivers may
 *			perform any initialization required before each
 *			hardware operation in this callback; drivers can
 *			access/modify the buffer here as it is still synced for
 *			the CPU; drivers that support %VIDIOC_CREATE_BUFS must
 *			also validate the buffer size; if an error is returned,
 *			the buffer will not be queued in driver; optional.
 * @buf_finish:		called before every dequeue of the buffer back to
 *			userspace; the buffer is synced for the CPU, so drivers
 *			can access/modify the buffer contents; drivers may
 *			perform any operations required before userspace
 *			accesses the buffer; optional. The buffer state can be
 *			one of the following: %DONE and %ERROR occur while
 *			streaming is in progress, and the %PREPARED state occurs
 *			when the queue has been canceled and all pending
 *			buffers are being returned to their default %DEQUEUED
 *			state. Typically you only have to do something if the
 *			state is %VB2_BUF_STATE_DONE, since in all other cases
 *			the buffer contents will be ignored anyway.
 * @buf_cleanup:	called once before the buffer is freed; drivers may
 *			perform any additional cleanup; optional.
 * @start_streaming:	called once to enter 'streaming' state; the driver may
 *			receive buffers with @buf_queue callback
 *			before @start_streaming is called; the driver gets the
 *			number of already queued buffers in count parameter;
 *			driver can return an error if hardware fails, in that
 *			case all buffers that have been already given by
 *			the @buf_queue callback are to be returned by the driver
 *			by calling @vb2_buffer_done\(%VB2_BUF_STATE_QUEUED\).
 *			If you need a minimum number of buffers before you can
 *			start streaming, then set @min_buffers_needed in the
 *			vb2_queue structure. If that is non-zero then
 *			start_streaming won't be called until at least that
 *			many buffers have been queued up by userspace.
 * @stop_streaming:	called when 'streaming' state must be disabled; driver
 *			should stop any DMA transactions or wait until they
 *			finish and give back all buffers it got from &buf_queue
 *			callback by calling @vb2_buffer_done\(\) with either
 *			%VB2_BUF_STATE_DONE or %VB2_BUF_STATE_ERROR; may use
 *			vb2_wait_for_all_buffers() function
 * @buf_queue:		passes buffer vb to the driver; driver may start
 *			hardware operation on this buffer; driver should give
 *			the buffer back by calling vb2_buffer_done() function;
 *			it is allways called after calling %VIDIOC_STREAMON ioctl;
 *			might be called before start_streaming callback if user
 *			pre-queued buffers before calling %VIDIOC_STREAMON.
 */
struct vb2_ops {
	int (*queue_setup)(struct vb2_queue *q,
			   unsigned int *num_buffers, unsigned int *num_planes,
			   unsigned int sizes[], struct device *alloc_devs[]);

	void (*wait_prepare)(struct vb2_queue *q);
	void (*wait_finish)(struct vb2_queue *q);

	int (*buf_init)(struct vb2_buffer *vb);
	int (*buf_prepare)(struct vb2_buffer *vb);
	void (*buf_finish)(struct vb2_buffer *vb);
	void (*buf_cleanup)(struct vb2_buffer *vb);

	int (*start_streaming)(struct vb2_queue *q, unsigned int count);
	void (*stop_streaming)(struct vb2_queue *q);

	void (*buf_queue)(struct vb2_buffer *vb);
};

/**
 * struct vb2_ops - driver-specific callbacks
 *
 * @verify_planes_array: Verify that a given user space structure contains
 *			enough planes for the buffer. This is called
 *			for each dequeued buffer.
 * @fill_user_buffer:	given a vb2_buffer fill in the userspace structure.
 *			For V4L2 this is a struct v4l2_buffer.
 * @fill_vb2_buffer:	given a userspace structure, fill in the vb2_buffer.
 *			If the userspace structure is invalid, then this op
 *			will return an error.
 * @copy_timestamp:	copy the timestamp from a userspace structure to
 *			the vb2_buffer struct.
 */
struct vb2_buf_ops {
	int (*verify_planes_array)(struct vb2_buffer *vb, const void *pb);
	void (*fill_user_buffer)(struct vb2_buffer *vb, void *pb);
	int (*fill_vb2_buffer)(struct vb2_buffer *vb, const void *pb,
				struct vb2_plane *planes);
	void (*copy_timestamp)(struct vb2_buffer *vb, const void *pb);
};

/**
 * struct vb2_queue - a videobuf queue
 *
 * @type:	private buffer type whose content is defined by the vb2-core
 *		caller. For example, for V4L2, it should match
 *		the V4L2_BUF_TYPE_* in include/uapi/linux/videodev2.h
 * @io_modes:	supported io methods (see vb2_io_modes enum)
 * @dev:	device to use for the default allocation context if the driver
 *		doesn't fill in the @alloc_devs array.
 * @dma_attrs:	DMA attributes to use for the DMA.
 * @fileio_read_once:		report EOF after reading the first buffer
 * @fileio_write_immediately:	queue buffer after each write() call
 * @allow_zero_bytesused:	allow bytesused == 0 to be passed to the driver
 * @quirk_poll_must_check_waiting_for_buffers: Return POLLERR at poll when QBUF
 *              has not been called. This is a vb1 idiom that has been adopted
 *              also by vb2.
 * @lock:	pointer to a mutex that protects the vb2_queue struct. The
 *		driver can set this to a mutex to let the v4l2 core serialize
 *		the queuing ioctls. If the driver wants to handle locking
 *		itself, then this should be set to NULL. This lock is not used
 *		by the videobuf2 core API.
 * @owner:	The filehandle that 'owns' the buffers, i.e. the filehandle
 *		that called reqbufs, create_buffers or started fileio.
 *		This field is not used by the videobuf2 core API, but it allows
 *		drivers to easily associate an owner filehandle with the queue.
 * @ops:	driver-specific callbacks
 * @mem_ops:	memory allocator specific callbacks
 * @buf_ops:	callbacks to deliver buffer information
 *		between user-space and kernel-space
 * @drv_priv:	driver private data
 * @buf_struct_size: size of the driver-specific buffer structure;
 *		"0" indicates the driver doesn't want to use a custom buffer
 *		structure type. for example, sizeof(struct vb2_v4l2_buffer)
 *		will be used for v4l2.
 * @timestamp_flags: Timestamp flags; V4L2_BUF_FLAG_TIMESTAMP_* and
 *		V4L2_BUF_FLAG_TSTAMP_SRC_*
 * @gfp_flags:	additional gfp flags used when allocating the buffers.
 *		Typically this is 0, but it may be e.g. GFP_DMA or __GFP_DMA32
 *		to force the buffer allocation to a specific memory zone.
 * @min_buffers_needed: the minimum number of buffers needed before
 *		start_streaming() can be called. Used when a DMA engine
 *		cannot be started unless at least this number of buffers
 *		have been queued into the driver.
 */
/*
 * Private elements (won't appear at the DocBook):
 * @mmap_lock:	private mutex used when buffers are allocated/freed/mmapped
 * @memory:	current memory type used
 * @bufs:	videobuf buffer structures
 * @num_buffers: number of allocated/used buffers
 * @queued_list: list of buffers currently queued from userspace
 * @queued_count: number of buffers queued and ready for streaming.
 * @owned_by_drv_count: number of buffers owned by the driver
 * @done_list:	list of buffers ready to be dequeued to userspace
 * @done_lock:	lock to protect done_list list
 * @done_wq:	waitqueue for processes waiting for buffers ready to be dequeued
 * @alloc_devs:	memory type/allocator-specific per-plane device
 * @streaming:	current streaming state
 * @start_streaming_called: start_streaming() was called successfully and we
 *		started streaming.
 * @error:	a fatal error occurred on the queue
 * @waiting_for_buffers: used in poll() to check if vb2 is still waiting for
 *		buffers. Only set for capture queues if qbuf has not yet been
 *		called since poll() needs to return POLLERR in that situation.
 * @is_multiplanar: set if buffer type is multiplanar
 * @is_output:	set if buffer type is output
 * @copy_timestamp: set if vb2-core should set timestamps
 * @last_buffer_dequeued: used in poll() and DQBUF to immediately return if the
 *		last decoded buffer was already dequeued. Set for capture queues
 *		when a buffer with the V4L2_BUF_FLAG_LAST is dequeued.
 * @fileio:	file io emulator internal data, used only if emulator is active
 * @threadio:	thread io internal data, used only if thread is active
 */
struct vb2_queue {
	unsigned int			type;
	unsigned int			io_modes;
	struct device			*dev;
	unsigned long			dma_attrs;
	unsigned			fileio_read_once:1;
	unsigned			fileio_write_immediately:1;
	unsigned			allow_zero_bytesused:1;
	unsigned		   quirk_poll_must_check_waiting_for_buffers:1;

	struct mutex			*lock;
	void				*owner;

	const struct vb2_ops		*ops;
	const struct vb2_mem_ops	*mem_ops;
	const struct vb2_buf_ops	*buf_ops;

	void				*drv_priv;
	unsigned int			buf_struct_size;
	u32				timestamp_flags;
	gfp_t				gfp_flags;
	u32				min_buffers_needed;

	/* private: internal use only */
	struct mutex			mmap_lock;
	unsigned int			memory;
	struct vb2_buffer		*bufs[VB2_MAX_FRAME];
	unsigned int			num_buffers;

	struct list_head		queued_list;
	unsigned int			queued_count;

	atomic_t			owned_by_drv_count;
	struct list_head		done_list;
	spinlock_t			done_lock;
	wait_queue_head_t		done_wq;

	struct device			*alloc_devs[VB2_MAX_PLANES];

	unsigned int			streaming:1;
	unsigned int			start_streaming_called:1;
	unsigned int			error:1;
	unsigned int			waiting_for_buffers:1;
	unsigned int			is_multiplanar:1;
	unsigned int			is_output:1;
	unsigned int			copy_timestamp:1;
	unsigned int			last_buffer_dequeued:1;

	struct vb2_fileio_data		*fileio;
	struct vb2_threadio_data	*threadio;

#ifdef CONFIG_VIDEO_ADV_DEBUG
	/*
	 * Counters for how often these queue-related ops are
	 * called. Used to check for unbalanced ops.
	 */
	u32				cnt_queue_setup;
	u32				cnt_wait_prepare;
	u32				cnt_wait_finish;
	u32				cnt_start_streaming;
	u32				cnt_stop_streaming;
#endif
};

void *vb2_plane_vaddr(struct vb2_buffer *vb, unsigned int plane_no);
void *vb2_plane_cookie(struct vb2_buffer *vb, unsigned int plane_no);

void vb2_buffer_done(struct vb2_buffer *vb, enum vb2_buffer_state state);
void vb2_discard_done(struct vb2_queue *q);
int vb2_wait_for_all_buffers(struct vb2_queue *q);

void vb2_core_querybuf(struct vb2_queue *q, unsigned int index, void *pb);
int vb2_core_reqbufs(struct vb2_queue *q, enum vb2_memory memory,
		unsigned int *count);
int vb2_core_create_bufs(struct vb2_queue *q, enum vb2_memory memory,
		unsigned int *count, unsigned requested_planes,
		const unsigned int requested_sizes[]);
int vb2_core_prepare_buf(struct vb2_queue *q, unsigned int index, void *pb);
int vb2_core_qbuf(struct vb2_queue *q, unsigned int index, void *pb);
int vb2_core_dqbuf(struct vb2_queue *q, unsigned int *pindex, void *pb,
		   bool nonblocking);

int vb2_core_streamon(struct vb2_queue *q, unsigned int type);
int vb2_core_streamoff(struct vb2_queue *q, unsigned int type);

int vb2_core_expbuf(struct vb2_queue *q, int *fd, unsigned int type,
		unsigned int index, unsigned int plane, unsigned int flags);

int vb2_core_queue_init(struct vb2_queue *q);
void vb2_core_queue_release(struct vb2_queue *q);

void vb2_queue_error(struct vb2_queue *q);

int vb2_mmap(struct vb2_queue *q, struct vm_area_struct *vma);
#ifndef CONFIG_MMU
unsigned long vb2_get_unmapped_area(struct vb2_queue *q,
				    unsigned long addr,
				    unsigned long len,
				    unsigned long pgoff,
				    unsigned long flags);
#endif
unsigned int vb2_core_poll(struct vb2_queue *q, struct file *file,
		poll_table *wait);
size_t vb2_read(struct vb2_queue *q, char __user *data, size_t count,
		loff_t *ppos, int nonblock);
size_t vb2_write(struct vb2_queue *q, const char __user *data, size_t count,
		loff_t *ppos, int nonblock);

/*
 * vb2_thread_fnc - callback function for use with vb2_thread
 *
 * This is called whenever a buffer is dequeued in the thread.
 */
typedef int (*vb2_thread_fnc)(struct vb2_buffer *vb, void *priv);

/**
 * vb2_thread_start() - start a thread for the given queue.
 * @q:		videobuf queue
 * @fnc:	callback function
 * @priv:	priv pointer passed to the callback function
 * @thread_name:the name of the thread. This will be prefixed with "vb2-".
 *
 * This starts a thread that will queue and dequeue until an error occurs
 * or @vb2_thread_stop is called.
 *
 * This function should not be used for anything else but the videobuf2-dvb
 * support. If you think you have another good use-case for this, then please
 * contact the linux-media mailinglist first.
 */
int vb2_thread_start(struct vb2_queue *q, vb2_thread_fnc fnc, void *priv,
		     const char *thread_name);

/**
 * vb2_thread_stop() - stop the thread for the given queue.
 * @q:		videobuf queue
 */
int vb2_thread_stop(struct vb2_queue *q);

/**
 * vb2_is_streaming() - return streaming status of the queue
 * @q:		videobuf queue
 */
static inline bool vb2_is_streaming(struct vb2_queue *q)
{
	return q->streaming;
}

/**
 * vb2_fileio_is_active() - return true if fileio is active.
 * @q:		videobuf queue
 *
 * This returns true if read() or write() is used to stream the data
 * as opposed to stream I/O. This is almost never an important distinction,
 * except in rare cases. One such case is that using read() or write() to
 * stream a format using V4L2_FIELD_ALTERNATE is not allowed since there
 * is no way you can pass the field information of each buffer to/from
 * userspace. A driver that supports this field format should check for
 * this in the queue_setup op and reject it if this function returns true.
 */
static inline bool vb2_fileio_is_active(struct vb2_queue *q)
{
	return q->fileio;
}

/**
 * vb2_is_busy() - return busy status of the queue
 * @q:		videobuf queue
 *
 * This function checks if queue has any buffers allocated.
 */
static inline bool vb2_is_busy(struct vb2_queue *q)
{
	return (q->num_buffers > 0);
}

/**
 * vb2_get_drv_priv() - return driver private data associated with the queue
 * @q:		videobuf queue
 */
static inline void *vb2_get_drv_priv(struct vb2_queue *q)
{
	return q->drv_priv;
}

/**
 * vb2_set_plane_payload() - set bytesused for the plane plane_no
 * @vb:		buffer for which plane payload should be set
 * @plane_no:	plane number for which payload should be set
 * @size:	payload in bytes
 */
static inline void vb2_set_plane_payload(struct vb2_buffer *vb,
				 unsigned int plane_no, unsigned long size)
{
	if (plane_no < vb->num_planes)
		vb->planes[plane_no].bytesused = size;
}

/**
 * vb2_get_plane_payload() - get bytesused for the plane plane_no
 * @vb:		buffer for which plane payload should be set
 * @plane_no:	plane number for which payload should be set
 */
static inline unsigned long vb2_get_plane_payload(struct vb2_buffer *vb,
				 unsigned int plane_no)
{
	if (plane_no < vb->num_planes)
		return vb->planes[plane_no].bytesused;
	return 0;
}

/**
 * vb2_plane_size() - return plane size in bytes
 * @vb:		buffer for which plane size should be returned
 * @plane_no:	plane number for which size should be returned
 */
static inline unsigned long
vb2_plane_size(struct vb2_buffer *vb, unsigned int plane_no)
{
	if (plane_no < vb->num_planes)
		return vb->planes[plane_no].length;
	return 0;
}

/**
 * vb2_start_streaming_called() - return streaming status of driver
 * @q:		videobuf queue
 */
static inline bool vb2_start_streaming_called(struct vb2_queue *q)
{
	return q->start_streaming_called;
}

/**
 * vb2_clear_last_buffer_dequeued() - clear last buffer dequeued flag of queue
 * @q:		videobuf queue
 */
static inline void vb2_clear_last_buffer_dequeued(struct vb2_queue *q)
{
	q->last_buffer_dequeued = false;
}

/*
 * The following functions are not part of the vb2 core API, but are useful
 * functions for videobuf2-*.
 */
bool vb2_buffer_in_use(struct vb2_queue *q, struct vb2_buffer *vb);
int vb2_verify_memory_type(struct vb2_queue *q,
		enum vb2_memory memory, unsigned int type);
#endif /* _MEDIA_VIDEOBUF2_CORE_H */