xref: /linux/include/media/videobuf2-core.h (revision ca55b2fef3a9373fcfc30f82fd26bc7fccbda732)
1 /*
2  * videobuf2-core.h - V4L2 driver helper framework
3  *
4  * Copyright (C) 2010 Samsung Electronics
5  *
6  * Author: Pawel Osciak <pawel@osciak.com>
7  *
8  * This program is free software; you can redistribute it and/or modify
9  * it under the terms of the GNU General Public License as published by
10  * the Free Software Foundation.
11  */
12 #ifndef _MEDIA_VIDEOBUF2_CORE_H
13 #define _MEDIA_VIDEOBUF2_CORE_H
14 
15 #include <linux/mm_types.h>
16 #include <linux/mutex.h>
17 #include <linux/poll.h>
18 #include <linux/videodev2.h>
19 #include <linux/dma-buf.h>
20 
21 struct vb2_alloc_ctx;
22 struct vb2_fileio_data;
23 struct vb2_threadio_data;
24 
25 /**
26  * struct vb2_mem_ops - memory handling/memory allocator operations
27  * @alloc:	allocate video memory and, optionally, allocator private data,
28  *		return NULL on failure or a pointer to allocator private,
29  *		per-buffer data on success; the returned private structure
30  *		will then be passed as buf_priv argument to other ops in this
31  *		structure. Additional gfp_flags to use when allocating the
32  *		are also passed to this operation. These flags are from the
33  *		gfp_flags field of vb2_queue.
34  * @put:	inform the allocator that the buffer will no longer be used;
35  *		usually will result in the allocator freeing the buffer (if
36  *		no other users of this buffer are present); the buf_priv
37  *		argument is the allocator private per-buffer structure
38  *		previously returned from the alloc callback.
39  * @get_userptr: acquire userspace memory for a hardware operation; used for
40  *		 USERPTR memory types; vaddr is the address passed to the
41  *		 videobuf layer when queuing a video buffer of USERPTR type;
42  *		 should return an allocator private per-buffer structure
43  *		 associated with the buffer on success, NULL on failure;
44  *		 the returned private structure will then be passed as buf_priv
45  *		 argument to other ops in this structure.
46  * @put_userptr: inform the allocator that a USERPTR buffer will no longer
47  *		 be used.
48  * @attach_dmabuf: attach a shared struct dma_buf for a hardware operation;
49  *		   used for DMABUF memory types; alloc_ctx is the alloc context
50  *		   dbuf is the shared dma_buf; returns NULL on failure;
51  *		   allocator private per-buffer structure on success;
52  *		   this needs to be used for further accesses to the buffer.
53  * @detach_dmabuf: inform the exporter of the buffer that the current DMABUF
54  *		   buffer is no longer used; the buf_priv argument is the
55  *		   allocator private per-buffer structure previously returned
56  *		   from the attach_dmabuf callback.
57  * @map_dmabuf: request for access to the dmabuf from allocator; the allocator
58  *		of dmabuf is informed that this driver is going to use the
59  *		dmabuf.
60  * @unmap_dmabuf: releases access control to the dmabuf - allocator is notified
61  *		  that this driver is done using the dmabuf for now.
62  * @prepare:	called every time the buffer is passed from userspace to the
63  *		driver, useful for cache synchronisation, optional.
64  * @finish:	called every time the buffer is passed back from the driver
65  *		to the userspace, also optional.
66  * @vaddr:	return a kernel virtual address to a given memory buffer
67  *		associated with the passed private structure or NULL if no
68  *		such mapping exists.
69  * @cookie:	return allocator specific cookie for a given memory buffer
70  *		associated with the passed private structure or NULL if not
71  *		available.
72  * @num_users:	return the current number of users of a memory buffer;
73  *		return 1 if the videobuf layer (or actually the driver using
74  *		it) is the only user.
75  * @mmap:	setup a userspace mapping for a given memory buffer under
76  *		the provided virtual memory region.
77  *
78  * Required ops for USERPTR types: get_userptr, put_userptr.
79  * Required ops for MMAP types: alloc, put, num_users, mmap.
80  * Required ops for read/write access types: alloc, put, num_users, vaddr.
81  * Required ops for DMABUF types: attach_dmabuf, detach_dmabuf, map_dmabuf,
82  *				  unmap_dmabuf.
83  */
84 struct vb2_mem_ops {
85 	void		*(*alloc)(void *alloc_ctx, unsigned long size,
86 				  enum dma_data_direction dma_dir,
87 				  gfp_t gfp_flags);
88 	void		(*put)(void *buf_priv);
89 	struct dma_buf *(*get_dmabuf)(void *buf_priv, unsigned long flags);
90 
91 	void		*(*get_userptr)(void *alloc_ctx, unsigned long vaddr,
92 					unsigned long size,
93 					enum dma_data_direction dma_dir);
94 	void		(*put_userptr)(void *buf_priv);
95 
96 	void		(*prepare)(void *buf_priv);
97 	void		(*finish)(void *buf_priv);
98 
99 	void		*(*attach_dmabuf)(void *alloc_ctx, struct dma_buf *dbuf,
100 					  unsigned long size,
101 					  enum dma_data_direction dma_dir);
102 	void		(*detach_dmabuf)(void *buf_priv);
103 	int		(*map_dmabuf)(void *buf_priv);
104 	void		(*unmap_dmabuf)(void *buf_priv);
105 
106 	void		*(*vaddr)(void *buf_priv);
107 	void		*(*cookie)(void *buf_priv);
108 
109 	unsigned int	(*num_users)(void *buf_priv);
110 
111 	int		(*mmap)(void *buf_priv, struct vm_area_struct *vma);
112 };
113 
114 struct vb2_plane {
115 	void			*mem_priv;
116 	struct dma_buf		*dbuf;
117 	unsigned int		dbuf_mapped;
118 };
119 
120 /**
121  * enum vb2_io_modes - queue access methods
122  * @VB2_MMAP:		driver supports MMAP with streaming API
123  * @VB2_USERPTR:	driver supports USERPTR with streaming API
124  * @VB2_READ:		driver supports read() style access
125  * @VB2_WRITE:		driver supports write() style access
126  * @VB2_DMABUF:		driver supports DMABUF with streaming API
127  */
128 enum vb2_io_modes {
129 	VB2_MMAP	= (1 << 0),
130 	VB2_USERPTR	= (1 << 1),
131 	VB2_READ	= (1 << 2),
132 	VB2_WRITE	= (1 << 3),
133 	VB2_DMABUF	= (1 << 4),
134 };
135 
136 /**
137  * enum vb2_buffer_state - current video buffer state
138  * @VB2_BUF_STATE_DEQUEUED:	buffer under userspace control
139  * @VB2_BUF_STATE_PREPARING:	buffer is being prepared in videobuf
140  * @VB2_BUF_STATE_PREPARED:	buffer prepared in videobuf and by the driver
141  * @VB2_BUF_STATE_QUEUED:	buffer queued in videobuf, but not in driver
142  * @VB2_BUF_STATE_REQUEUEING:	re-queue a buffer to the driver
143  * @VB2_BUF_STATE_ACTIVE:	buffer queued in driver and possibly used
144  *				in a hardware operation
145  * @VB2_BUF_STATE_DONE:		buffer returned from driver to videobuf, but
146  *				not yet dequeued to userspace
147  * @VB2_BUF_STATE_ERROR:	same as above, but the operation on the buffer
148  *				has ended with an error, which will be reported
149  *				to the userspace when it is dequeued
150  */
151 enum vb2_buffer_state {
152 	VB2_BUF_STATE_DEQUEUED,
153 	VB2_BUF_STATE_PREPARING,
154 	VB2_BUF_STATE_PREPARED,
155 	VB2_BUF_STATE_QUEUED,
156 	VB2_BUF_STATE_REQUEUEING,
157 	VB2_BUF_STATE_ACTIVE,
158 	VB2_BUF_STATE_DONE,
159 	VB2_BUF_STATE_ERROR,
160 };
161 
162 struct vb2_queue;
163 
164 /**
165  * struct vb2_buffer - represents a video buffer
166  * @v4l2_buf:		struct v4l2_buffer associated with this buffer; can
167  *			be read by the driver and relevant entries can be
168  *			changed by the driver in case of CAPTURE types
169  *			(such as timestamp)
170  * @v4l2_planes:	struct v4l2_planes associated with this buffer; can
171  *			be read by the driver and relevant entries can be
172  *			changed by the driver in case of CAPTURE types
173  *			(such as bytesused); NOTE that even for single-planar
174  *			types, the v4l2_planes[0] struct should be used
175  *			instead of v4l2_buf for filling bytesused - drivers
176  *			should use the vb2_set_plane_payload() function for that
177  * @vb2_queue:		the queue to which this driver belongs
178  * @num_planes:		number of planes in the buffer
179  *			on an internal driver queue
180  * @state:		current buffer state; do not change
181  * @queued_entry:	entry on the queued buffers list, which holds all
182  *			buffers queued from userspace
183  * @done_entry:		entry on the list that stores all buffers ready to
184  *			be dequeued to userspace
185  * @planes:		private per-plane information; do not change
186  */
187 struct vb2_buffer {
188 	struct v4l2_buffer	v4l2_buf;
189 	struct v4l2_plane	v4l2_planes[VIDEO_MAX_PLANES];
190 
191 	struct vb2_queue	*vb2_queue;
192 
193 	unsigned int		num_planes;
194 
195 /* Private: internal use only */
196 	enum vb2_buffer_state	state;
197 
198 	struct list_head	queued_entry;
199 	struct list_head	done_entry;
200 
201 	struct vb2_plane	planes[VIDEO_MAX_PLANES];
202 
203 #ifdef CONFIG_VIDEO_ADV_DEBUG
204 	/*
205 	 * Counters for how often these buffer-related ops are
206 	 * called. Used to check for unbalanced ops.
207 	 */
208 	u32		cnt_mem_alloc;
209 	u32		cnt_mem_put;
210 	u32		cnt_mem_get_dmabuf;
211 	u32		cnt_mem_get_userptr;
212 	u32		cnt_mem_put_userptr;
213 	u32		cnt_mem_prepare;
214 	u32		cnt_mem_finish;
215 	u32		cnt_mem_attach_dmabuf;
216 	u32		cnt_mem_detach_dmabuf;
217 	u32		cnt_mem_map_dmabuf;
218 	u32		cnt_mem_unmap_dmabuf;
219 	u32		cnt_mem_vaddr;
220 	u32		cnt_mem_cookie;
221 	u32		cnt_mem_num_users;
222 	u32		cnt_mem_mmap;
223 
224 	u32		cnt_buf_init;
225 	u32		cnt_buf_prepare;
226 	u32		cnt_buf_finish;
227 	u32		cnt_buf_cleanup;
228 	u32		cnt_buf_queue;
229 
230 	/* This counts the number of calls to vb2_buffer_done() */
231 	u32		cnt_buf_done;
232 #endif
233 };
234 
235 /**
236  * struct vb2_ops - driver-specific callbacks
237  *
238  * @queue_setup:	called from VIDIOC_REQBUFS and VIDIOC_CREATE_BUFS
239  *			handlers before memory allocation, or, if
240  *			*num_planes != 0, after the allocation to verify a
241  *			smaller number of buffers. Driver should return
242  *			the required number of buffers in *num_buffers, the
243  *			required number of planes per buffer in *num_planes; the
244  *			size of each plane should be set in the sizes[] array
245  *			and optional per-plane allocator specific context in the
246  *			alloc_ctxs[] array. When called from VIDIOC_REQBUFS,
247  *			fmt == NULL, the driver has to use the currently
248  *			configured format and *num_buffers is the total number
249  *			of buffers, that are being allocated. When called from
250  *			VIDIOC_CREATE_BUFS, fmt != NULL and it describes the
251  *			target frame format (if the format isn't valid the
252  *			callback must return -EINVAL). In this case *num_buffers
253  *			are being allocated additionally to q->num_buffers.
254  * @wait_prepare:	release any locks taken while calling vb2 functions;
255  *			it is called before an ioctl needs to wait for a new
256  *			buffer to arrive; required to avoid a deadlock in
257  *			blocking access type.
258  * @wait_finish:	reacquire all locks released in the previous callback;
259  *			required to continue operation after sleeping while
260  *			waiting for a new buffer to arrive.
261  * @buf_init:		called once after allocating a buffer (in MMAP case)
262  *			or after acquiring a new USERPTR buffer; drivers may
263  *			perform additional buffer-related initialization;
264  *			initialization failure (return != 0) will prevent
265  *			queue setup from completing successfully; optional.
266  * @buf_prepare:	called every time the buffer is queued from userspace
267  *			and from the VIDIOC_PREPARE_BUF ioctl; drivers may
268  *			perform any initialization required before each
269  *			hardware operation in this callback; drivers can
270  *			access/modify the buffer here as it is still synced for
271  *			the CPU; drivers that support VIDIOC_CREATE_BUFS must
272  *			also validate the buffer size; if an error is returned,
273  *			the buffer will not be queued in driver; optional.
274  * @buf_finish:		called before every dequeue of the buffer back to
275  *			userspace; the buffer is synced for the CPU, so drivers
276  *			can access/modify the buffer contents; drivers may
277  *			perform any operations required before userspace
278  *			accesses the buffer; optional. The buffer state can be
279  *			one of the following: DONE and ERROR occur while
280  *			streaming is in progress, and the PREPARED state occurs
281  *			when the queue has been canceled and all pending
282  *			buffers are being returned to their default DEQUEUED
283  *			state. Typically you only have to do something if the
284  *			state is VB2_BUF_STATE_DONE, since in all other cases
285  *			the buffer contents will be ignored anyway.
286  * @buf_cleanup:	called once before the buffer is freed; drivers may
287  *			perform any additional cleanup; optional.
288  * @start_streaming:	called once to enter 'streaming' state; the driver may
289  *			receive buffers with @buf_queue callback before
290  *			@start_streaming is called; the driver gets the number
291  *			of already queued buffers in count parameter; driver
292  *			can return an error if hardware fails, in that case all
293  *			buffers that have been already given by the @buf_queue
294  *			callback are to be returned by the driver by calling
295  *			@vb2_buffer_done(VB2_BUF_STATE_QUEUED).
296  *			If you need a minimum number of buffers before you can
297  *			start streaming, then set @min_buffers_needed in the
298  *			vb2_queue structure. If that is non-zero then
299  *			start_streaming won't be called until at least that
300  *			many buffers have been queued up by userspace.
301  * @stop_streaming:	called when 'streaming' state must be disabled; driver
302  *			should stop any DMA transactions or wait until they
303  *			finish and give back all buffers it got from buf_queue()
304  *			callback by calling @vb2_buffer_done() with either
305  *			VB2_BUF_STATE_DONE or VB2_BUF_STATE_ERROR; may use
306  *			vb2_wait_for_all_buffers() function
307  * @buf_queue:		passes buffer vb to the driver; driver may start
308  *			hardware operation on this buffer; driver should give
309  *			the buffer back by calling vb2_buffer_done() function;
310  *			it is allways called after calling STREAMON ioctl;
311  *			might be called before start_streaming callback if user
312  *			pre-queued buffers before calling STREAMON.
313  */
314 struct vb2_ops {
315 	int (*queue_setup)(struct vb2_queue *q, const struct v4l2_format *fmt,
316 			   unsigned int *num_buffers, unsigned int *num_planes,
317 			   unsigned int sizes[], void *alloc_ctxs[]);
318 
319 	void (*wait_prepare)(struct vb2_queue *q);
320 	void (*wait_finish)(struct vb2_queue *q);
321 
322 	int (*buf_init)(struct vb2_buffer *vb);
323 	int (*buf_prepare)(struct vb2_buffer *vb);
324 	void (*buf_finish)(struct vb2_buffer *vb);
325 	void (*buf_cleanup)(struct vb2_buffer *vb);
326 
327 	int (*start_streaming)(struct vb2_queue *q, unsigned int count);
328 	void (*stop_streaming)(struct vb2_queue *q);
329 
330 	void (*buf_queue)(struct vb2_buffer *vb);
331 };
332 
333 struct v4l2_fh;
334 
335 /**
336  * struct vb2_queue - a videobuf queue
337  *
338  * @type:	queue type (see V4L2_BUF_TYPE_* in linux/videodev2.h
339  * @io_modes:	supported io methods (see vb2_io_modes enum)
340  * @fileio_read_once:		report EOF after reading the first buffer
341  * @fileio_write_immediately:	queue buffer after each write() call
342  * @allow_zero_bytesused:	allow bytesused == 0 to be passed to the driver
343  * @lock:	pointer to a mutex that protects the vb2_queue struct. The
344  *		driver can set this to a mutex to let the v4l2 core serialize
345  *		the queuing ioctls. If the driver wants to handle locking
346  *		itself, then this should be set to NULL. This lock is not used
347  *		by the videobuf2 core API.
348  * @owner:	The filehandle that 'owns' the buffers, i.e. the filehandle
349  *		that called reqbufs, create_buffers or started fileio.
350  *		This field is not used by the videobuf2 core API, but it allows
351  *		drivers to easily associate an owner filehandle with the queue.
352  * @ops:	driver-specific callbacks
353  * @mem_ops:	memory allocator specific callbacks
354  * @drv_priv:	driver private data
355  * @buf_struct_size: size of the driver-specific buffer structure;
356  *		"0" indicates the driver doesn't want to use a custom buffer
357  *		structure type, so sizeof(struct vb2_buffer) will is used
358  * @timestamp_flags: Timestamp flags; V4L2_BUF_FLAG_TIMESTAMP_* and
359  *		V4L2_BUF_FLAG_TSTAMP_SRC_*
360  * @gfp_flags:	additional gfp flags used when allocating the buffers.
361  *		Typically this is 0, but it may be e.g. GFP_DMA or __GFP_DMA32
362  *		to force the buffer allocation to a specific memory zone.
363  * @min_buffers_needed: the minimum number of buffers needed before
364  *		start_streaming() can be called. Used when a DMA engine
365  *		cannot be started unless at least this number of buffers
366  *		have been queued into the driver.
367  */
368 /*
369  * Private elements (won't appear at the DocBook):
370  * @mmap_lock:	private mutex used when buffers are allocated/freed/mmapped
371  * @memory:	current memory type used
372  * @bufs:	videobuf buffer structures
373  * @num_buffers: number of allocated/used buffers
374  * @queued_list: list of buffers currently queued from userspace
375  * @queued_count: number of buffers queued and ready for streaming.
376  * @owned_by_drv_count: number of buffers owned by the driver
377  * @done_list:	list of buffers ready to be dequeued to userspace
378  * @done_lock:	lock to protect done_list list
379  * @done_wq:	waitqueue for processes waiting for buffers ready to be dequeued
380  * @alloc_ctx:	memory type/allocator-specific contexts for each plane
381  * @streaming:	current streaming state
382  * @start_streaming_called: start_streaming() was called successfully and we
383  *		started streaming.
384  * @error:	a fatal error occurred on the queue
385  * @waiting_for_buffers: used in poll() to check if vb2 is still waiting for
386  *		buffers. Only set for capture queues if qbuf has not yet been
387  *		called since poll() needs to return POLLERR in that situation.
388  * @last_buffer_dequeued: used in poll() and DQBUF to immediately return if the
389  *		last decoded buffer was already dequeued. Set for capture queues
390  *		when a buffer with the V4L2_BUF_FLAG_LAST is dequeued.
391  * @fileio:	file io emulator internal data, used only if emulator is active
392  * @threadio:	thread io internal data, used only if thread is active
393  */
394 struct vb2_queue {
395 	enum v4l2_buf_type		type;
396 	unsigned int			io_modes;
397 	unsigned			fileio_read_once:1;
398 	unsigned			fileio_write_immediately:1;
399 	unsigned			allow_zero_bytesused:1;
400 
401 	struct mutex			*lock;
402 	struct v4l2_fh			*owner;
403 
404 	const struct vb2_ops		*ops;
405 	const struct vb2_mem_ops	*mem_ops;
406 	void				*drv_priv;
407 	unsigned int			buf_struct_size;
408 	u32				timestamp_flags;
409 	gfp_t				gfp_flags;
410 	u32				min_buffers_needed;
411 
412 	/* private: internal use only */
413 	struct mutex			mmap_lock;
414 	enum v4l2_memory		memory;
415 	struct vb2_buffer		*bufs[VIDEO_MAX_FRAME];
416 	unsigned int			num_buffers;
417 
418 	struct list_head		queued_list;
419 	unsigned int			queued_count;
420 
421 	atomic_t			owned_by_drv_count;
422 	struct list_head		done_list;
423 	spinlock_t			done_lock;
424 	wait_queue_head_t		done_wq;
425 
426 	void				*alloc_ctx[VIDEO_MAX_PLANES];
427 	unsigned int			plane_sizes[VIDEO_MAX_PLANES];
428 
429 	unsigned int			streaming:1;
430 	unsigned int			start_streaming_called:1;
431 	unsigned int			error:1;
432 	unsigned int			waiting_for_buffers:1;
433 	unsigned int			last_buffer_dequeued:1;
434 
435 	struct vb2_fileio_data		*fileio;
436 	struct vb2_threadio_data	*threadio;
437 
438 #ifdef CONFIG_VIDEO_ADV_DEBUG
439 	/*
440 	 * Counters for how often these queue-related ops are
441 	 * called. Used to check for unbalanced ops.
442 	 */
443 	u32				cnt_queue_setup;
444 	u32				cnt_wait_prepare;
445 	u32				cnt_wait_finish;
446 	u32				cnt_start_streaming;
447 	u32				cnt_stop_streaming;
448 #endif
449 };
450 
451 void *vb2_plane_vaddr(struct vb2_buffer *vb, unsigned int plane_no);
452 void *vb2_plane_cookie(struct vb2_buffer *vb, unsigned int plane_no);
453 
454 void vb2_buffer_done(struct vb2_buffer *vb, enum vb2_buffer_state state);
455 void vb2_discard_done(struct vb2_queue *q);
456 int vb2_wait_for_all_buffers(struct vb2_queue *q);
457 
458 int vb2_querybuf(struct vb2_queue *q, struct v4l2_buffer *b);
459 int vb2_reqbufs(struct vb2_queue *q, struct v4l2_requestbuffers *req);
460 
461 int vb2_create_bufs(struct vb2_queue *q, struct v4l2_create_buffers *create);
462 int vb2_prepare_buf(struct vb2_queue *q, struct v4l2_buffer *b);
463 
464 int __must_check vb2_queue_init(struct vb2_queue *q);
465 
466 void vb2_queue_release(struct vb2_queue *q);
467 void vb2_queue_error(struct vb2_queue *q);
468 
469 int vb2_qbuf(struct vb2_queue *q, struct v4l2_buffer *b);
470 int vb2_expbuf(struct vb2_queue *q, struct v4l2_exportbuffer *eb);
471 int vb2_dqbuf(struct vb2_queue *q, struct v4l2_buffer *b, bool nonblocking);
472 
473 int vb2_streamon(struct vb2_queue *q, enum v4l2_buf_type type);
474 int vb2_streamoff(struct vb2_queue *q, enum v4l2_buf_type type);
475 
476 int vb2_mmap(struct vb2_queue *q, struct vm_area_struct *vma);
477 #ifndef CONFIG_MMU
478 unsigned long vb2_get_unmapped_area(struct vb2_queue *q,
479 				    unsigned long addr,
480 				    unsigned long len,
481 				    unsigned long pgoff,
482 				    unsigned long flags);
483 #endif
484 unsigned int vb2_poll(struct vb2_queue *q, struct file *file, poll_table *wait);
485 size_t vb2_read(struct vb2_queue *q, char __user *data, size_t count,
486 		loff_t *ppos, int nonblock);
487 size_t vb2_write(struct vb2_queue *q, const char __user *data, size_t count,
488 		loff_t *ppos, int nonblock);
489 
490 /*
491  * vb2_thread_fnc - callback function for use with vb2_thread
492  *
493  * This is called whenever a buffer is dequeued in the thread.
494  */
495 typedef int (*vb2_thread_fnc)(struct vb2_buffer *vb, void *priv);
496 
497 /**
498  * vb2_thread_start() - start a thread for the given queue.
499  * @q:		videobuf queue
500  * @fnc:	callback function
501  * @priv:	priv pointer passed to the callback function
502  * @thread_name:the name of the thread. This will be prefixed with "vb2-".
503  *
504  * This starts a thread that will queue and dequeue until an error occurs
505  * or @vb2_thread_stop is called.
506  *
507  * This function should not be used for anything else but the videobuf2-dvb
508  * support. If you think you have another good use-case for this, then please
509  * contact the linux-media mailinglist first.
510  */
511 int vb2_thread_start(struct vb2_queue *q, vb2_thread_fnc fnc, void *priv,
512 		     const char *thread_name);
513 
514 /**
515  * vb2_thread_stop() - stop the thread for the given queue.
516  * @q:		videobuf queue
517  */
518 int vb2_thread_stop(struct vb2_queue *q);
519 
520 /**
521  * vb2_is_streaming() - return streaming status of the queue
522  * @q:		videobuf queue
523  */
524 static inline bool vb2_is_streaming(struct vb2_queue *q)
525 {
526 	return q->streaming;
527 }
528 
529 /**
530  * vb2_fileio_is_active() - return true if fileio is active.
531  * @q:		videobuf queue
532  *
533  * This returns true if read() or write() is used to stream the data
534  * as opposed to stream I/O. This is almost never an important distinction,
535  * except in rare cases. One such case is that using read() or write() to
536  * stream a format using V4L2_FIELD_ALTERNATE is not allowed since there
537  * is no way you can pass the field information of each buffer to/from
538  * userspace. A driver that supports this field format should check for
539  * this in the queue_setup op and reject it if this function returns true.
540  */
541 static inline bool vb2_fileio_is_active(struct vb2_queue *q)
542 {
543 	return q->fileio;
544 }
545 
546 /**
547  * vb2_is_busy() - return busy status of the queue
548  * @q:		videobuf queue
549  *
550  * This function checks if queue has any buffers allocated.
551  */
552 static inline bool vb2_is_busy(struct vb2_queue *q)
553 {
554 	return (q->num_buffers > 0);
555 }
556 
557 /**
558  * vb2_get_drv_priv() - return driver private data associated with the queue
559  * @q:		videobuf queue
560  */
561 static inline void *vb2_get_drv_priv(struct vb2_queue *q)
562 {
563 	return q->drv_priv;
564 }
565 
566 /**
567  * vb2_set_plane_payload() - set bytesused for the plane plane_no
568  * @vb:		buffer for which plane payload should be set
569  * @plane_no:	plane number for which payload should be set
570  * @size:	payload in bytes
571  */
572 static inline void vb2_set_plane_payload(struct vb2_buffer *vb,
573 				 unsigned int plane_no, unsigned long size)
574 {
575 	if (plane_no < vb->num_planes)
576 		vb->v4l2_planes[plane_no].bytesused = size;
577 }
578 
579 /**
580  * vb2_get_plane_payload() - get bytesused for the plane plane_no
581  * @vb:		buffer for which plane payload should be set
582  * @plane_no:	plane number for which payload should be set
583  */
584 static inline unsigned long vb2_get_plane_payload(struct vb2_buffer *vb,
585 				 unsigned int plane_no)
586 {
587 	if (plane_no < vb->num_planes)
588 		return vb->v4l2_planes[plane_no].bytesused;
589 	return 0;
590 }
591 
592 /**
593  * vb2_plane_size() - return plane size in bytes
594  * @vb:		buffer for which plane size should be returned
595  * @plane_no:	plane number for which size should be returned
596  */
597 static inline unsigned long
598 vb2_plane_size(struct vb2_buffer *vb, unsigned int plane_no)
599 {
600 	if (plane_no < vb->num_planes)
601 		return vb->v4l2_planes[plane_no].length;
602 	return 0;
603 }
604 
605 /**
606  * vb2_start_streaming_called() - return streaming status of driver
607  * @q:		videobuf queue
608  */
609 static inline bool vb2_start_streaming_called(struct vb2_queue *q)
610 {
611 	return q->start_streaming_called;
612 }
613 
614 /**
615  * vb2_clear_last_buffer_dequeued() - clear last buffer dequeued flag of queue
616  * @q:		videobuf queue
617  */
618 static inline void vb2_clear_last_buffer_dequeued(struct vb2_queue *q)
619 {
620 	q->last_buffer_dequeued = false;
621 }
622 
623 /*
624  * The following functions are not part of the vb2 core API, but are simple
625  * helper functions that you can use in your struct v4l2_file_operations,
626  * struct v4l2_ioctl_ops and struct vb2_ops. They will serialize if vb2_queue->lock
627  * or video_device->lock is set, and they will set and test vb2_queue->owner
628  * to check if the calling filehandle is permitted to do the queuing operation.
629  */
630 
631 /* struct v4l2_ioctl_ops helpers */
632 
633 int vb2_ioctl_reqbufs(struct file *file, void *priv,
634 			  struct v4l2_requestbuffers *p);
635 int vb2_ioctl_create_bufs(struct file *file, void *priv,
636 			  struct v4l2_create_buffers *p);
637 int vb2_ioctl_prepare_buf(struct file *file, void *priv,
638 			  struct v4l2_buffer *p);
639 int vb2_ioctl_querybuf(struct file *file, void *priv, struct v4l2_buffer *p);
640 int vb2_ioctl_qbuf(struct file *file, void *priv, struct v4l2_buffer *p);
641 int vb2_ioctl_dqbuf(struct file *file, void *priv, struct v4l2_buffer *p);
642 int vb2_ioctl_streamon(struct file *file, void *priv, enum v4l2_buf_type i);
643 int vb2_ioctl_streamoff(struct file *file, void *priv, enum v4l2_buf_type i);
644 int vb2_ioctl_expbuf(struct file *file, void *priv,
645 	struct v4l2_exportbuffer *p);
646 
647 /* struct v4l2_file_operations helpers */
648 
649 int vb2_fop_mmap(struct file *file, struct vm_area_struct *vma);
650 int vb2_fop_release(struct file *file);
651 int _vb2_fop_release(struct file *file, struct mutex *lock);
652 ssize_t vb2_fop_write(struct file *file, const char __user *buf,
653 		size_t count, loff_t *ppos);
654 ssize_t vb2_fop_read(struct file *file, char __user *buf,
655 		size_t count, loff_t *ppos);
656 unsigned int vb2_fop_poll(struct file *file, poll_table *wait);
657 #ifndef CONFIG_MMU
658 unsigned long vb2_fop_get_unmapped_area(struct file *file, unsigned long addr,
659 		unsigned long len, unsigned long pgoff, unsigned long flags);
660 #endif
661 
662 /* struct vb2_ops helpers, only use if vq->lock is non-NULL. */
663 
664 void vb2_ops_wait_prepare(struct vb2_queue *vq);
665 void vb2_ops_wait_finish(struct vb2_queue *vq);
666 
667 #endif /* _MEDIA_VIDEOBUF2_CORE_H */
668