1/*
2 * videobuf2-core.h - Video Buffer 2 Core 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/dma-buf.h>
19#include <linux/bitops.h>
20#include <media/media-request.h>
21#include <media/frame_vector.h>
22
23#define VB2_MAX_FRAME (32)
24#define VB2_MAX_PLANES (8)
25
26/**
27 * enum vb2_memory - type of memory model used to make the buffers visible
28 * on userspace.
29 *
30 * @VB2_MEMORY_UNKNOWN: Buffer status is unknown or it is not used yet on
31 * userspace.
32 * @VB2_MEMORY_MMAP: The buffers are allocated by the Kernel and it is
33 * memory mapped via mmap() ioctl. This model is
34 * also used when the user is using the buffers via
35 * read() or write() system calls.
36 * @VB2_MEMORY_USERPTR: The buffers was allocated in userspace and it is
37 * memory mapped via mmap() ioctl.
38 * @VB2_MEMORY_DMABUF: The buffers are passed to userspace via DMA buffer.
39 */
40enum vb2_memory {
41 VB2_MEMORY_UNKNOWN = 0,
42 VB2_MEMORY_MMAP = 1,
43 VB2_MEMORY_USERPTR = 2,
44 VB2_MEMORY_DMABUF = 4,
45};
46
47struct vb2_fileio_data;
48struct vb2_threadio_data;
49struct vb2_buffer;
50
51/**
52 * struct vb2_mem_ops - memory handling/memory allocator operations.
53 * @alloc: allocate video memory and, optionally, allocator private data,
54 * return ERR_PTR() on failure or a pointer to allocator private,
55 * per-buffer data on success; the returned private structure
56 * will then be passed as @buf_priv argument to other ops in this
57 * structure. The size argument to this function shall be
58 * *page aligned*.
59 * @put: inform the allocator that the buffer will no longer be used;
60 * usually will result in the allocator freeing the buffer (if
61 * no other users of this buffer are present); the @buf_priv
62 * argument is the allocator private per-buffer structure
63 * previously returned from the alloc callback.
64 * @get_dmabuf: acquire userspace memory for a hardware operation; used for
65 * DMABUF memory types.
66 * @get_userptr: acquire userspace memory for a hardware operation; used for
67 * USERPTR memory types; vaddr is the address passed to the
68 * videobuf2 layer when queuing a video buffer of USERPTR type;
69 * should return an allocator private per-buffer structure
70 * associated with the buffer on success, ERR_PTR() on failure;
71 * the returned private structure will then be passed as @buf_priv
72 * argument to other ops in this structure.
73 * @put_userptr: inform the allocator that a USERPTR buffer will no longer
74 * be used.
75 * @attach_dmabuf: attach a shared &struct dma_buf for a hardware operation;
76 * used for DMABUF memory types; dev is the alloc device
77 * dbuf is the shared dma_buf; returns ERR_PTR() on failure;
78 * allocator private per-buffer structure on success;
79 * this needs to be used for further accesses to the buffer.
80 * @detach_dmabuf: inform the exporter of the buffer that the current DMABUF
81 * buffer is no longer used; the @buf_priv argument is the
82 * allocator private per-buffer structure previously returned
83 * from the attach_dmabuf callback.
84 * @map_dmabuf: request for access to the dmabuf from allocator; the allocator
85 * of dmabuf is informed that this driver is going to use the
86 * dmabuf.
87 * @unmap_dmabuf: releases access control to the dmabuf - allocator is notified
88 * that this driver is done using the dmabuf for now.
89 * @prepare: called every time the buffer is passed from userspace to the
90 * driver, useful for cache synchronisation, optional.
91 * @finish: called every time the buffer is passed back from the driver
92 * to the userspace, also optional.
93 * @vaddr: return a kernel virtual address to a given memory buffer
94 * associated with the passed private structure or NULL if no
95 * such mapping exists.
96 * @cookie: return allocator specific cookie for a given memory buffer
97 * associated with the passed private structure or NULL if not
98 * available.
99 * @num_users: return the current number of users of a memory buffer;
100 * return 1 if the videobuf2 layer (or actually the driver using
101 * it) is the only user.
102 * @mmap: setup a userspace mapping for a given memory buffer under
103 * the provided virtual memory region.
104 *
105 * Those operations are used by the videobuf2 core to implement the memory
106 * handling/memory allocators for each type of supported streaming I/O method.
107 *
108 * .. note::
109 * #) Required ops for USERPTR types: get_userptr, put_userptr.
110 *
111 * #) Required ops for MMAP types: alloc, put, num_users, mmap.
112 *
113 * #) Required ops for read/write access types: alloc, put, num_users, vaddr.
114 *
115 * #) Required ops for DMABUF types: attach_dmabuf, detach_dmabuf,
116 * map_dmabuf, unmap_dmabuf.
117 */
118struct vb2_mem_ops {
119 void *(*alloc)(struct vb2_buffer *vb,
120 struct device *dev,
121 unsigned long size);
122 void (*put)(void *buf_priv);
123 struct dma_buf *(*get_dmabuf)(struct vb2_buffer *vb,
124 void *buf_priv,
125 unsigned long flags);
126
127 void *(*get_userptr)(struct vb2_buffer *vb,
128 struct device *dev,
129 unsigned long vaddr,
130 unsigned long size);
131 void (*put_userptr)(void *buf_priv);
132
133 void (*prepare)(void *buf_priv);
134 void (*finish)(void *buf_priv);
135
136 void *(*attach_dmabuf)(struct vb2_buffer *vb,
137 struct device *dev,
138 struct dma_buf *dbuf,
139 unsigned long size);
140 void (*detach_dmabuf)(void *buf_priv);
141 int (*map_dmabuf)(void *buf_priv);
142 void (*unmap_dmabuf)(void *buf_priv);
143
144 void *(*vaddr)(struct vb2_buffer *vb, void *buf_priv);
145 void *(*cookie)(struct vb2_buffer *vb, void *buf_priv);
146
147 unsigned int (*num_users)(void *buf_priv);
148
149 int (*mmap)(void *buf_priv, struct vm_area_struct *vma);
150};
151
152/**
153 * struct vb2_plane - plane information.
154 * @mem_priv: private data with this plane.
155 * @dbuf: dma_buf - shared buffer object.
156 * @dbuf_mapped: flag to show whether dbuf is mapped or not
157 * @bytesused: number of bytes occupied by data in the plane (payload).
158 * @length: size of this plane (NOT the payload) in bytes. The maximum
159 * valid size is MAX_UINT - PAGE_SIZE.
160 * @min_length: minimum required size of this plane (NOT the payload) in bytes.
161 * @length is always greater or equal to @min_length, and like
162 * @length, it is limited to MAX_UINT - PAGE_SIZE.
163 * @m: Union with memtype-specific data.
164 * @m.offset: when memory in the associated struct vb2_buffer is
165 * %VB2_MEMORY_MMAP, equals the offset from the start of
166 * the device memory for this plane (or is a "cookie" that
167 * should be passed to mmap() called on the video node).
168 * @m.userptr: when memory is %VB2_MEMORY_USERPTR, a userspace pointer
169 * pointing to this plane.
170 * @m.fd: when memory is %VB2_MEMORY_DMABUF, a userspace file
171 * descriptor associated with this plane.
172 * @data_offset: offset in the plane to the start of data; usually 0,
173 * unless there is a header in front of the data.
174 *
175 * Should contain enough information to be able to cover all the fields
176 * of &struct v4l2_plane at videodev2.h.
177 */
178struct vb2_plane {
179 void *mem_priv;
180 struct dma_buf *dbuf;
181 unsigned int dbuf_mapped;
182 unsigned int bytesused;
183 unsigned int length;
184 unsigned int min_length;
185 union {
186 unsigned int offset;
187 unsigned long userptr;
188 int fd;
189 } m;
190 unsigned int data_offset;
191};
192
193/**
194 * enum vb2_io_modes - queue access methods.
195 * @VB2_MMAP: driver supports MMAP with streaming API.
196 * @VB2_USERPTR: driver supports USERPTR with streaming API.
197 * @VB2_READ: driver supports read() style access.
198 * @VB2_WRITE: driver supports write() style access.
199 * @VB2_DMABUF: driver supports DMABUF with streaming API.
200 */
201enum vb2_io_modes {
202 VB2_MMAP = BIT(0),
203 VB2_USERPTR = BIT(1),
204 VB2_READ = BIT(2),
205 VB2_WRITE = BIT(3),
206 VB2_DMABUF = BIT(4),
207};
208
209/**
210 * enum vb2_buffer_state - current video buffer state.
211 * @VB2_BUF_STATE_DEQUEUED: buffer under userspace control.
212 * @VB2_BUF_STATE_IN_REQUEST: buffer is queued in media request.
213 * @VB2_BUF_STATE_PREPARING: buffer is being prepared in videobuf2.
214 * @VB2_BUF_STATE_QUEUED: buffer queued in videobuf2, but not in driver.
215 * @VB2_BUF_STATE_ACTIVE: buffer queued in driver and possibly used
216 * in a hardware operation.
217 * @VB2_BUF_STATE_DONE: buffer returned from driver to videobuf2, but
218 * not yet dequeued to userspace.
219 * @VB2_BUF_STATE_ERROR: same as above, but the operation on the buffer
220 * has ended with an error, which will be reported
221 * to the userspace when it is dequeued.
222 */
223enum vb2_buffer_state {
224 VB2_BUF_STATE_DEQUEUED,
225 VB2_BUF_STATE_IN_REQUEST,
226 VB2_BUF_STATE_PREPARING,
227 VB2_BUF_STATE_QUEUED,
228 VB2_BUF_STATE_ACTIVE,
229 VB2_BUF_STATE_DONE,
230 VB2_BUF_STATE_ERROR,
231};
232
233struct vb2_queue;
234
235/**
236 * struct vb2_buffer - represents a video buffer.
237 * @vb2_queue: pointer to &struct vb2_queue with the queue to
238 * which this driver belongs.
239 * @index: id number of the buffer.
240 * @type: buffer type.
241 * @memory: the method, in which the actual data is passed.
242 * @num_planes: number of planes in the buffer
243 * on an internal driver queue.
244 * @timestamp: frame timestamp in ns.
245 * @request: the request this buffer is associated with.
246 * @req_obj: used to bind this buffer to a request. This
247 * request object has a refcount.
248 */
249struct vb2_buffer {
250 struct vb2_queue *vb2_queue;
251 unsigned int index;
252 unsigned int type;
253 unsigned int memory;
254 unsigned int num_planes;
255 u64 timestamp;
256 struct media_request *request;
257 struct media_request_object req_obj;
258
259 /* private: internal use only
260 *
261 * state: current buffer state; do not change
262 * synced: this buffer has been synced for DMA, i.e. the
263 * 'prepare' memop was called. It is cleared again
264 * after the 'finish' memop is called.
265 * prepared: this buffer has been prepared, i.e. the
266 * buf_prepare op was called. It is cleared again
267 * after the 'buf_finish' op is called.
268 * copied_timestamp: the timestamp of this capture buffer was copied
269 * from an output buffer.
270 * skip_cache_sync_on_prepare: when set buffer's ->prepare() function
271 * skips cache sync/invalidation.
272 * skip_cache_sync_on_finish: when set buffer's ->finish() function
273 * skips cache sync/invalidation.
274 * queued_entry: entry on the queued buffers list, which holds
275 * all buffers queued from userspace
276 * done_entry: entry on the list that stores all buffers ready
277 * to be dequeued to userspace
278 * vb2_plane: per-plane information; do not change
279 */
280 enum vb2_buffer_state state;
281 unsigned int synced:1;
282 unsigned int prepared:1;
283 unsigned int copied_timestamp:1;
284 unsigned int skip_cache_sync_on_prepare:1;
285 unsigned int skip_cache_sync_on_finish:1;
286
287 struct vb2_plane planes[VB2_MAX_PLANES];
288 struct list_head queued_entry;
289 struct list_head done_entry;
290#ifdef CONFIG_VIDEO_ADV_DEBUG
291 /*
292 * Counters for how often these buffer-related ops are
293 * called. Used to check for unbalanced ops.
294 */
295 u32 cnt_mem_alloc;
296 u32 cnt_mem_put;
297 u32 cnt_mem_get_dmabuf;
298 u32 cnt_mem_get_userptr;
299 u32 cnt_mem_put_userptr;
300 u32 cnt_mem_prepare;
301 u32 cnt_mem_finish;
302 u32 cnt_mem_attach_dmabuf;
303 u32 cnt_mem_detach_dmabuf;
304 u32 cnt_mem_map_dmabuf;
305 u32 cnt_mem_unmap_dmabuf;
306 u32 cnt_mem_vaddr;
307 u32 cnt_mem_cookie;
308 u32 cnt_mem_num_users;
309 u32 cnt_mem_mmap;
310
311 u32 cnt_buf_out_validate;
312 u32 cnt_buf_init;
313 u32 cnt_buf_prepare;
314 u32 cnt_buf_finish;
315 u32 cnt_buf_cleanup;
316 u32 cnt_buf_queue;
317 u32 cnt_buf_request_complete;
318
319 /* This counts the number of calls to vb2_buffer_done() */
320 u32 cnt_buf_done;
321#endif
322};
323
324/**
325 * struct vb2_ops - driver-specific callbacks.
326 *
327 * These operations are not called from interrupt context except where
328 * mentioned specifically.
329 *
330 * @queue_setup: called from VIDIOC_REQBUFS() and VIDIOC_CREATE_BUFS()
331 * handlers before memory allocation. It can be called
332 * twice: if the original number of requested buffers
333 * could not be allocated, then it will be called a
334 * second time with the actually allocated number of
335 * buffers to verify if that is OK.
336 * The driver should return the required number of buffers
337 * in \*num_buffers, the required number of planes per
338 * buffer in \*num_planes, the size of each plane should be
339 * set in the sizes\[\] array and optional per-plane
340 * allocator specific device in the alloc_devs\[\] array.
341 * When called from VIDIOC_REQBUFS(), \*num_planes == 0,
342 * the driver has to use the currently configured format to
343 * determine the plane sizes and \*num_buffers is the total
344 * number of buffers that are being allocated. When called
345 * from VIDIOC_CREATE_BUFS(), \*num_planes != 0 and it
346 * describes the requested number of planes and sizes\[\]
347 * contains the requested plane sizes. In this case
348 * \*num_buffers are being allocated additionally to
349 * q->num_buffers. If either \*num_planes or the requested
350 * sizes are invalid callback must return %-EINVAL.
351 * @wait_prepare: release any locks taken while calling vb2 functions;
352 * it is called before an ioctl needs to wait for a new
353 * buffer to arrive; required to avoid a deadlock in
354 * blocking access type.
355 * @wait_finish: reacquire all locks released in the previous callback;
356 * required to continue operation after sleeping while
357 * waiting for a new buffer to arrive.
358 * @buf_out_validate: called when the output buffer is prepared or queued
359 * to a request; drivers can use this to validate
360 * userspace-provided information; this is required only
361 * for OUTPUT queues.
362 * @buf_init: called once after allocating a buffer (in MMAP case)
363 * or after acquiring a new USERPTR buffer; drivers may
364 * perform additional buffer-related initialization;
365 * initialization failure (return != 0) will prevent
366 * queue setup from completing successfully; optional.
367 * @buf_prepare: called every time the buffer is queued from userspace
368 * and from the VIDIOC_PREPARE_BUF() ioctl; drivers may
369 * perform any initialization required before each
370 * hardware operation in this callback; drivers can
371 * access/modify the buffer here as it is still synced for
372 * the CPU; drivers that support VIDIOC_CREATE_BUFS() must
373 * also validate the buffer size; if an error is returned,
374 * the buffer will not be queued in driver; optional.
375 * @buf_finish: called before every dequeue of the buffer back to
376 * userspace; the buffer is synced for the CPU, so drivers
377 * can access/modify the buffer contents; drivers may
378 * perform any operations required before userspace
379 * accesses the buffer; optional. The buffer state can be
380 * one of the following: %DONE and %ERROR occur while
381 * streaming is in progress, and the %PREPARED state occurs
382 * when the queue has been canceled and all pending
383 * buffers are being returned to their default %DEQUEUED
384 * state. Typically you only have to do something if the
385 * state is %VB2_BUF_STATE_DONE, since in all other cases
386 * the buffer contents will be ignored anyway.
387 * @buf_cleanup: called once before the buffer is freed; drivers may
388 * perform any additional cleanup; optional.
389 * @prepare_streaming: called once to prepare for 'streaming' state; this is
390 * where validation can be done to verify everything is
391 * okay and streaming resources can be claimed. It is
392 * called when the VIDIOC_STREAMON ioctl is called. The
393 * actual streaming starts when @start_streaming is called.
394 * Optional.
395 * @start_streaming: called once to enter 'streaming' state; the driver may
396 * receive buffers with @buf_queue callback
397 * before @start_streaming is called; the driver gets the
398 * number of already queued buffers in count parameter;
399 * driver can return an error if hardware fails, in that
400 * case all buffers that have been already given by
401 * the @buf_queue callback are to be returned by the driver
402 * by calling vb2_buffer_done() with %VB2_BUF_STATE_QUEUED.
403 * If you need a minimum number of buffers before you can
404 * start streaming, then set
405 * &vb2_queue->min_buffers_needed. If that is non-zero
406 * then @start_streaming won't be called until at least
407 * that many buffers have been queued up by userspace.
408 * @stop_streaming: called when 'streaming' state must be disabled; driver
409 * should stop any DMA transactions or wait until they
410 * finish and give back all buffers it got from &buf_queue
411 * callback by calling vb2_buffer_done() with either
412 * %VB2_BUF_STATE_DONE or %VB2_BUF_STATE_ERROR; may use
413 * vb2_wait_for_all_buffers() function
414 * @unprepare_streaming:called as counterpart to @prepare_streaming; any claimed
415 * streaming resources can be released here. It is
416 * called when the VIDIOC_STREAMOFF ioctls is called or
417 * when the streaming filehandle is closed. Optional.
418 * @buf_queue: passes buffer vb to the driver; driver may start
419 * hardware operation on this buffer; driver should give
420 * the buffer back by calling vb2_buffer_done() function;
421 * it is always called after calling VIDIOC_STREAMON()
422 * ioctl; might be called before @start_streaming callback
423 * if user pre-queued buffers before calling
424 * VIDIOC_STREAMON().
425 * @buf_request_complete: a buffer that was never queued to the driver but is
426 * associated with a queued request was canceled.
427 * The driver will have to mark associated objects in the
428 * request as completed; required if requests are
429 * supported.
430 */
431struct vb2_ops {
432 int (*queue_setup)(struct vb2_queue *q,
433 unsigned int *num_buffers, unsigned int *num_planes,
434 unsigned int sizes[], struct device *alloc_devs[]);
435
436 void (*wait_prepare)(struct vb2_queue *q);
437 void (*wait_finish)(struct vb2_queue *q);
438
439 int (*buf_out_validate)(struct vb2_buffer *vb);
440 int (*buf_init)(struct vb2_buffer *vb);
441 int (*buf_prepare)(struct vb2_buffer *vb);
442 void (*buf_finish)(struct vb2_buffer *vb);
443 void (*buf_cleanup)(struct vb2_buffer *vb);
444
445 int (*prepare_streaming)(struct vb2_queue *q);
446 int (*start_streaming)(struct vb2_queue *q, unsigned int count);
447 void (*stop_streaming)(struct vb2_queue *q);
448 void (*unprepare_streaming)(struct vb2_queue *q);
449
450 void (*buf_queue)(struct vb2_buffer *vb);
451
452 void (*buf_request_complete)(struct vb2_buffer *vb);
453};
454
455/**
456 * struct vb2_buf_ops - driver-specific callbacks.
457 *
458 * @verify_planes_array: Verify that a given user space structure contains
459 * enough planes for the buffer. This is called
460 * for each dequeued buffer.
461 * @init_buffer: given a &vb2_buffer initialize the extra data after
462 * struct vb2_buffer.
463 * For V4L2 this is a &struct vb2_v4l2_buffer.
464 * @fill_user_buffer: given a &vb2_buffer fill in the userspace structure.
465 * For V4L2 this is a &struct v4l2_buffer.
466 * @fill_vb2_buffer: given a userspace structure, fill in the &vb2_buffer.
467 * If the userspace structure is invalid, then this op
468 * will return an error.
469 * @copy_timestamp: copy the timestamp from a userspace structure to
470 * the &struct vb2_buffer.
471 */
472struct vb2_buf_ops {
473 int (*verify_planes_array)(struct vb2_buffer *vb, const void *pb);
474 void (*init_buffer)(struct vb2_buffer *vb);
475 void (*fill_user_buffer)(struct vb2_buffer *vb, void *pb);
476 int (*fill_vb2_buffer)(struct vb2_buffer *vb, struct vb2_plane *planes);
477 void (*copy_timestamp)(struct vb2_buffer *vb, const void *pb);
478};
479
480/**
481 * struct vb2_queue - a videobuf2 queue.
482 *
483 * @type: private buffer type whose content is defined by the vb2-core
484 * caller. For example, for V4L2, it should match
485 * the types defined on &enum v4l2_buf_type.
486 * @io_modes: supported io methods (see &enum vb2_io_modes).
487 * @alloc_devs: &struct device memory type/allocator-specific per-plane device
488 * @dev: device to use for the default allocation context if the driver
489 * doesn't fill in the @alloc_devs array.
490 * @dma_attrs: DMA attributes to use for the DMA.
491 * @bidirectional: when this flag is set the DMA direction for the buffers of
492 * this queue will be overridden with %DMA_BIDIRECTIONAL direction.
493 * This is useful in cases where the hardware (firmware) writes to
494 * a buffer which is mapped as read (%DMA_TO_DEVICE), or reads from
495 * buffer which is mapped for write (%DMA_FROM_DEVICE) in order
496 * to satisfy some internal hardware restrictions or adds a padding
497 * needed by the processing algorithm. In case the DMA mapping is
498 * not bidirectional but the hardware (firmware) trying to access
499 * the buffer (in the opposite direction) this could lead to an
500 * IOMMU protection faults.
501 * @fileio_read_once: report EOF after reading the first buffer
502 * @fileio_write_immediately: queue buffer after each write() call
503 * @allow_zero_bytesused: allow bytesused == 0 to be passed to the driver
504 * @quirk_poll_must_check_waiting_for_buffers: Return %EPOLLERR at poll when QBUF
505 * has not been called. This is a vb1 idiom that has been adopted
506 * also by vb2.
507 * @supports_requests: this queue supports the Request API.
508 * @requires_requests: this queue requires the Request API. If this is set to 1,
509 * then supports_requests must be set to 1 as well.
510 * @uses_qbuf: qbuf was used directly for this queue. Set to 1 the first
511 * time this is called. Set to 0 when the queue is canceled.
512 * If this is 1, then you cannot queue buffers from a request.
513 * @uses_requests: requests are used for this queue. Set to 1 the first time
514 * a request is queued. Set to 0 when the queue is canceled.
515 * If this is 1, then you cannot queue buffers directly.
516 * @allow_cache_hints: when set user-space can pass cache management hints in
517 * order to skip cache flush/invalidation on ->prepare() or/and
518 * ->finish().
519 * @non_coherent_mem: when set queue will attempt to allocate buffers using
520 * non-coherent memory.
521 * @lock: pointer to a mutex that protects the &struct vb2_queue. The
522 * driver can set this to a mutex to let the v4l2 core serialize
523 * the queuing ioctls. If the driver wants to handle locking
524 * itself, then this should be set to NULL. This lock is not used
525 * by the videobuf2 core API.
526 * @owner: The filehandle that 'owns' the buffers, i.e. the filehandle
527 * that called reqbufs, create_buffers or started fileio.
528 * This field is not used by the videobuf2 core API, but it allows
529 * drivers to easily associate an owner filehandle with the queue.
530 * @ops: driver-specific callbacks
531 * @mem_ops: memory allocator specific callbacks
532 * @buf_ops: callbacks to deliver buffer information.
533 * between user-space and kernel-space.
534 * @drv_priv: driver private data.
535 * @subsystem_flags: Flags specific to the subsystem (V4L2/DVB/etc.). Not used
536 * by the vb2 core.
537 * @buf_struct_size: size of the driver-specific buffer structure;
538 * "0" indicates the driver doesn't want to use a custom buffer
539 * structure type. In that case a subsystem-specific struct
540 * will be used (in the case of V4L2 that is
541 * ``sizeof(struct vb2_v4l2_buffer)``). The first field of the
542 * driver-specific buffer structure must be the subsystem-specific
543 * struct (vb2_v4l2_buffer in the case of V4L2).
544 * @timestamp_flags: Timestamp flags; ``V4L2_BUF_FLAG_TIMESTAMP_*`` and
545 * ``V4L2_BUF_FLAG_TSTAMP_SRC_*``
546 * @gfp_flags: additional gfp flags used when allocating the buffers.
547 * Typically this is 0, but it may be e.g. %GFP_DMA or %__GFP_DMA32
548 * to force the buffer allocation to a specific memory zone.
549 * @min_buffers_needed: the minimum number of buffers needed before
550 * @start_streaming can be called. Used when a DMA engine
551 * cannot be started unless at least this number of buffers
552 * have been queued into the driver.
553 */
554/*
555 * Private elements (won't appear at the uAPI book):
556 * @mmap_lock: private mutex used when buffers are allocated/freed/mmapped
557 * @memory: current memory type used
558 * @dma_dir: DMA mapping direction.
559 * @bufs: videobuf2 buffer structures
560 * @num_buffers: number of allocated/used buffers
561 * @queued_list: list of buffers currently queued from userspace
562 * @queued_count: number of buffers queued and ready for streaming.
563 * @owned_by_drv_count: number of buffers owned by the driver
564 * @done_list: list of buffers ready to be dequeued to userspace
565 * @done_lock: lock to protect done_list list
566 * @done_wq: waitqueue for processes waiting for buffers ready to be dequeued
567 * @streaming: current streaming state
568 * @start_streaming_called: @start_streaming was called successfully and we
569 * started streaming.
570 * @error: a fatal error occurred on the queue
571 * @waiting_for_buffers: used in poll() to check if vb2 is still waiting for
572 * buffers. Only set for capture queues if qbuf has not yet been
573 * called since poll() needs to return %EPOLLERR in that situation.
574 * @is_multiplanar: set if buffer type is multiplanar
575 * @is_output: set if buffer type is output
576 * @copy_timestamp: set if vb2-core should set timestamps
577 * @last_buffer_dequeued: used in poll() and DQBUF to immediately return if the
578 * last decoded buffer was already dequeued. Set for capture queues
579 * when a buffer with the %V4L2_BUF_FLAG_LAST is dequeued.
580 * @fileio: file io emulator internal data, used only if emulator is active
581 * @threadio: thread io internal data, used only if thread is active
582 * @name: queue name, used for logging purpose. Initialized automatically
583 * if left empty by drivers.
584 */
585struct vb2_queue {
586 unsigned int type;
587 unsigned int io_modes;
588 struct device *dev;
589 unsigned long dma_attrs;
590 unsigned int bidirectional:1;
591 unsigned int fileio_read_once:1;
592 unsigned int fileio_write_immediately:1;
593 unsigned int allow_zero_bytesused:1;
594 unsigned int quirk_poll_must_check_waiting_for_buffers:1;
595 unsigned int supports_requests:1;
596 unsigned int requires_requests:1;
597 unsigned int uses_qbuf:1;
598 unsigned int uses_requests:1;
599 unsigned int allow_cache_hints:1;
600 unsigned int non_coherent_mem:1;
601
602 struct mutex *lock;
603 void *owner;
604
605 const struct vb2_ops *ops;
606 const struct vb2_mem_ops *mem_ops;
607 const struct vb2_buf_ops *buf_ops;
608
609 void *drv_priv;
610 u32 subsystem_flags;
611 unsigned int buf_struct_size;
612 u32 timestamp_flags;
613 gfp_t gfp_flags;
614 u32 min_buffers_needed;
615
616 struct device *alloc_devs[VB2_MAX_PLANES];
617
618 /* private: internal use only */
619 struct mutex mmap_lock;
620 unsigned int memory;
621 enum dma_data_direction dma_dir;
622 struct vb2_buffer *bufs[VB2_MAX_FRAME];
623 unsigned int num_buffers;
624
625 struct list_head queued_list;
626 unsigned int queued_count;
627
628 atomic_t owned_by_drv_count;
629 struct list_head done_list;
630 spinlock_t done_lock;
631 wait_queue_head_t done_wq;
632
633 unsigned int streaming:1;
634 unsigned int start_streaming_called:1;
635 unsigned int error:1;
636 unsigned int waiting_for_buffers:1;
637 unsigned int waiting_in_dqbuf:1;
638 unsigned int is_multiplanar:1;
639 unsigned int is_output:1;
640 unsigned int copy_timestamp:1;
641 unsigned int last_buffer_dequeued:1;
642
643 struct vb2_fileio_data *fileio;
644 struct vb2_threadio_data *threadio;
645
646 char name[32];
647
648#ifdef CONFIG_VIDEO_ADV_DEBUG
649 /*
650 * Counters for how often these queue-related ops are
651 * called. Used to check for unbalanced ops.
652 */
653 u32 cnt_queue_setup;
654 u32 cnt_wait_prepare;
655 u32 cnt_wait_finish;
656 u32 cnt_prepare_streaming;
657 u32 cnt_start_streaming;
658 u32 cnt_stop_streaming;
659 u32 cnt_unprepare_streaming;
660#endif
661};
662
663/**
664 * vb2_queue_allows_cache_hints() - Return true if the queue allows cache
665 * and memory consistency hints.
666 *
667 * @q: pointer to &struct vb2_queue with videobuf2 queue
668 */
669static inline bool vb2_queue_allows_cache_hints(struct vb2_queue *q)
670{
671 return q->allow_cache_hints && q->memory == VB2_MEMORY_MMAP;
672}
673
674/**
675 * vb2_plane_vaddr() - Return a kernel virtual address of a given plane.
676 * @vb: pointer to &struct vb2_buffer to which the plane in
677 * question belongs to.
678 * @plane_no: plane number for which the address is to be returned.
679 *
680 * This function returns a kernel virtual address of a given plane if
681 * such a mapping exist, NULL otherwise.
682 */
683void *vb2_plane_vaddr(struct vb2_buffer *vb, unsigned int plane_no);
684
685/**
686 * vb2_plane_cookie() - Return allocator specific cookie for the given plane.
687 * @vb: pointer to &struct vb2_buffer to which the plane in
688 * question belongs to.
689 * @plane_no: plane number for which the cookie is to be returned.
690 *
691 * This function returns an allocator specific cookie for a given plane if
692 * available, NULL otherwise. The allocator should provide some simple static
693 * inline function, which would convert this cookie to the allocator specific
694 * type that can be used directly by the driver to access the buffer. This can
695 * be for example physical address, pointer to scatter list or IOMMU mapping.
696 */
697void *vb2_plane_cookie(struct vb2_buffer *vb, unsigned int plane_no);
698
699/**
700 * vb2_buffer_done() - inform videobuf2 that an operation on a buffer
701 * is finished.
702 * @vb: pointer to &struct vb2_buffer to be used.
703 * @state: state of the buffer, as defined by &enum vb2_buffer_state.
704 * Either %VB2_BUF_STATE_DONE if the operation finished
705 * successfully, %VB2_BUF_STATE_ERROR if the operation finished
706 * with an error or %VB2_BUF_STATE_QUEUED.
707 *
708 * This function should be called by the driver after a hardware operation on
709 * a buffer is finished and the buffer may be returned to userspace. The driver
710 * cannot use this buffer anymore until it is queued back to it by videobuf
711 * by the means of &vb2_ops->buf_queue callback. Only buffers previously queued
712 * to the driver by &vb2_ops->buf_queue can be passed to this function.
713 *
714 * While streaming a buffer can only be returned in state DONE or ERROR.
715 * The &vb2_ops->start_streaming op can also return them in case the DMA engine
716 * cannot be started for some reason. In that case the buffers should be
717 * returned with state QUEUED to put them back into the queue.
718 */
719void vb2_buffer_done(struct vb2_buffer *vb, enum vb2_buffer_state state);
720
721/**
722 * vb2_discard_done() - discard all buffers marked as DONE.
723 * @q: pointer to &struct vb2_queue with videobuf2 queue.
724 *
725 * This function is intended to be used with suspend/resume operations. It
726 * discards all 'done' buffers as they would be too old to be requested after
727 * resume.
728 *
729 * Drivers must stop the hardware and synchronize with interrupt handlers and/or
730 * delayed works before calling this function to make sure no buffer will be
731 * touched by the driver and/or hardware.
732 */
733void vb2_discard_done(struct vb2_queue *q);
734
735/**
736 * vb2_wait_for_all_buffers() - wait until all buffers are given back to vb2.
737 * @q: pointer to &struct vb2_queue with videobuf2 queue.
738 *
739 * This function will wait until all buffers that have been given to the driver
740 * by &vb2_ops->buf_queue are given back to vb2 with vb2_buffer_done(). It
741 * doesn't call &vb2_ops->wait_prepare/&vb2_ops->wait_finish pair.
742 * It is intended to be called with all locks taken, for example from
743 * &vb2_ops->stop_streaming callback.
744 */
745int vb2_wait_for_all_buffers(struct vb2_queue *q);
746
747/**
748 * vb2_core_querybuf() - query video buffer information.
749 * @q: pointer to &struct vb2_queue with videobuf2 queue.
750 * @index: id number of the buffer.
751 * @pb: buffer struct passed from userspace.
752 *
753 * Videobuf2 core helper to implement VIDIOC_QUERYBUF() operation. It is called
754 * internally by VB2 by an API-specific handler, like ``videobuf2-v4l2.h``.
755 *
756 * The passed buffer should have been verified.
757 *
758 * This function fills the relevant information for the userspace.
759 *
760 * Return: returns zero on success; an error code otherwise.
761 */
762void vb2_core_querybuf(struct vb2_queue *q, unsigned int index, void *pb);
763
764/**
765 * vb2_core_reqbufs() - Initiate streaming.
766 * @q: pointer to &struct vb2_queue with videobuf2 queue.
767 * @memory: memory type, as defined by &enum vb2_memory.
768 * @flags: auxiliary queue/buffer management flags. Currently, the only
769 * used flag is %V4L2_MEMORY_FLAG_NON_COHERENT.
770 * @count: requested buffer count.
771 *
772 * Videobuf2 core helper to implement VIDIOC_REQBUF() operation. It is called
773 * internally by VB2 by an API-specific handler, like ``videobuf2-v4l2.h``.
774 *
775 * This function:
776 *
777 * #) verifies streaming parameters passed from the userspace;
778 * #) sets up the queue;
779 * #) negotiates number of buffers and planes per buffer with the driver
780 * to be used during streaming;
781 * #) allocates internal buffer structures (&struct vb2_buffer), according to
782 * the agreed parameters;
783 * #) for MMAP memory type, allocates actual video memory, using the
784 * memory handling/allocation routines provided during queue initialization.
785 *
786 * If req->count is 0, all the memory will be freed instead.
787 *
788 * If the queue has been allocated previously by a previous vb2_core_reqbufs()
789 * call and the queue is not busy, memory will be reallocated.
790 *
791 * Return: returns zero on success; an error code otherwise.
792 */
793int vb2_core_reqbufs(struct vb2_queue *q, enum vb2_memory memory,
794 unsigned int flags, unsigned int *count);
795
796/**
797 * vb2_core_create_bufs() - Allocate buffers and any required auxiliary structs
798 * @q: pointer to &struct vb2_queue with videobuf2 queue.
799 * @memory: memory type, as defined by &enum vb2_memory.
800 * @flags: auxiliary queue/buffer management flags.
801 * @count: requested buffer count.
802 * @requested_planes: number of planes requested.
803 * @requested_sizes: array with the size of the planes.
804 *
805 * Videobuf2 core helper to implement VIDIOC_CREATE_BUFS() operation. It is
806 * called internally by VB2 by an API-specific handler, like
807 * ``videobuf2-v4l2.h``.
808 *
809 * This function:
810 *
811 * #) verifies parameter sanity;
812 * #) calls the &vb2_ops->queue_setup queue operation;
813 * #) performs any necessary memory allocations.
814 *
815 * Return: returns zero on success; an error code otherwise.
816 */
817int vb2_core_create_bufs(struct vb2_queue *q, enum vb2_memory memory,
818 unsigned int flags, unsigned int *count,
819 unsigned int requested_planes,
820 const unsigned int requested_sizes[]);
821
822/**
823 * vb2_core_prepare_buf() - Pass ownership of a buffer from userspace
824 * to the kernel.
825 * @q: pointer to &struct vb2_queue with videobuf2 queue.
826 * @index: id number of the buffer.
827 * @pb: buffer structure passed from userspace to
828 * &v4l2_ioctl_ops->vidioc_prepare_buf handler in driver.
829 *
830 * Videobuf2 core helper to implement VIDIOC_PREPARE_BUF() operation. It is
831 * called internally by VB2 by an API-specific handler, like
832 * ``videobuf2-v4l2.h``.
833 *
834 * The passed buffer should have been verified.
835 *
836 * This function calls vb2_ops->buf_prepare callback in the driver
837 * (if provided), in which driver-specific buffer initialization can
838 * be performed.
839 *
840 * Return: returns zero on success; an error code otherwise.
841 */
842int vb2_core_prepare_buf(struct vb2_queue *q, unsigned int index, void *pb);
843
844/**
845 * vb2_core_qbuf() - Queue a buffer from userspace
846 *
847 * @q: pointer to &struct vb2_queue with videobuf2 queue.
848 * @index: id number of the buffer
849 * @pb: buffer structure passed from userspace to
850 * v4l2_ioctl_ops->vidioc_qbuf handler in driver
851 * @req: pointer to &struct media_request, may be NULL.
852 *
853 * Videobuf2 core helper to implement VIDIOC_QBUF() operation. It is called
854 * internally by VB2 by an API-specific handler, like ``videobuf2-v4l2.h``.
855 *
856 * This function:
857 *
858 * #) If @req is non-NULL, then the buffer will be bound to this
859 * media request and it returns. The buffer will be prepared and
860 * queued to the driver (i.e. the next two steps) when the request
861 * itself is queued.
862 * #) if necessary, calls &vb2_ops->buf_prepare callback in the driver
863 * (if provided), in which driver-specific buffer initialization can
864 * be performed;
865 * #) if streaming is on, queues the buffer in driver by the means of
866 * &vb2_ops->buf_queue callback for processing.
867 *
868 * Return: returns zero on success; an error code otherwise.
869 */
870int vb2_core_qbuf(struct vb2_queue *q, unsigned int index, void *pb,
871 struct media_request *req);
872
873/**
874 * vb2_core_dqbuf() - Dequeue a buffer to the userspace
875 * @q: pointer to &struct vb2_queue with videobuf2 queue
876 * @pindex: pointer to the buffer index. May be NULL
877 * @pb: buffer structure passed from userspace to
878 * v4l2_ioctl_ops->vidioc_dqbuf handler in driver.
879 * @nonblocking: if true, this call will not sleep waiting for a buffer if no
880 * buffers ready for dequeuing are present. Normally the driver
881 * would be passing (file->f_flags & O_NONBLOCK) here.
882 *
883 * Videobuf2 core helper to implement VIDIOC_DQBUF() operation. It is called
884 * internally by VB2 by an API-specific handler, like ``videobuf2-v4l2.h``.
885 *
886 * This function:
887 *
888 * #) calls buf_finish callback in the driver (if provided), in which
889 * driver can perform any additional operations that may be required before
890 * returning the buffer to userspace, such as cache sync,
891 * #) the buffer struct members are filled with relevant information for
892 * the userspace.
893 *
894 * Return: returns zero on success; an error code otherwise.
895 */
896int vb2_core_dqbuf(struct vb2_queue *q, unsigned int *pindex, void *pb,
897 bool nonblocking);
898
899/**
900 * vb2_core_streamon() - Implements VB2 stream ON logic
901 *
902 * @q: pointer to &struct vb2_queue with videobuf2 queue
903 * @type: type of the queue to be started.
904 * For V4L2, this is defined by &enum v4l2_buf_type type.
905 *
906 * Videobuf2 core helper to implement VIDIOC_STREAMON() operation. It is called
907 * internally by VB2 by an API-specific handler, like ``videobuf2-v4l2.h``.
908 *
909 * Return: returns zero on success; an error code otherwise.
910 */
911int vb2_core_streamon(struct vb2_queue *q, unsigned int type);
912
913/**
914 * vb2_core_streamoff() - Implements VB2 stream OFF logic
915 *
916 * @q: pointer to &struct vb2_queue with videobuf2 queue
917 * @type: type of the queue to be started.
918 * For V4L2, this is defined by &enum v4l2_buf_type type.
919 *
920 * Videobuf2 core helper to implement VIDIOC_STREAMOFF() operation. It is
921 * called internally by VB2 by an API-specific handler, like
922 * ``videobuf2-v4l2.h``.
923 *
924 * Return: returns zero on success; an error code otherwise.
925 */
926int vb2_core_streamoff(struct vb2_queue *q, unsigned int type);
927
928/**
929 * vb2_core_expbuf() - Export a buffer as a file descriptor.
930 * @q: pointer to &struct vb2_queue with videobuf2 queue.
931 * @fd: pointer to the file descriptor associated with DMABUF
932 * (set by driver).
933 * @type: buffer type.
934 * @index: id number of the buffer.
935 * @plane: index of the plane to be exported, 0 for single plane queues
936 * @flags: file flags for newly created file, as defined at
937 * include/uapi/asm-generic/fcntl.h.
938 * Currently, the only used flag is %O_CLOEXEC.
939 * is supported, refer to manual of open syscall for more details.
940 *
941 *
942 * Videobuf2 core helper to implement VIDIOC_EXPBUF() operation. It is called
943 * internally by VB2 by an API-specific handler, like ``videobuf2-v4l2.h``.
944 *
945 * Return: returns zero on success; an error code otherwise.
946 */
947int vb2_core_expbuf(struct vb2_queue *q, int *fd, unsigned int type,
948 unsigned int index, unsigned int plane, unsigned int flags);
949
950/**
951 * vb2_core_queue_init() - initialize a videobuf2 queue
952 * @q: pointer to &struct vb2_queue with videobuf2 queue.
953 * This structure should be allocated in driver
954 *
955 * The &vb2_queue structure should be allocated by the driver. The driver is
956 * responsible of clearing it's content and setting initial values for some
957 * required entries before calling this function.
958 *
959 * .. note::
960 *
961 * The following fields at @q should be set before calling this function:
962 * &vb2_queue->ops, &vb2_queue->mem_ops, &vb2_queue->type.
963 */
964int vb2_core_queue_init(struct vb2_queue *q);
965
966/**
967 * vb2_core_queue_release() - stop streaming, release the queue and free memory
968 * @q: pointer to &struct vb2_queue with videobuf2 queue.
969 *
970 * This function stops streaming and performs necessary clean ups, including
971 * freeing video buffer memory. The driver is responsible for freeing
972 * the &struct vb2_queue itself.
973 */
974void vb2_core_queue_release(struct vb2_queue *q);
975
976/**
977 * vb2_queue_error() - signal a fatal error on the queue
978 * @q: pointer to &struct vb2_queue with videobuf2 queue.
979 *
980 * Flag that a fatal unrecoverable error has occurred and wake up all processes
981 * waiting on the queue. Polling will now set %EPOLLERR and queuing and dequeuing
982 * buffers will return %-EIO.
983 *
984 * The error flag will be cleared when canceling the queue, either from
985 * vb2_streamoff() or vb2_queue_release(). Drivers should thus not call this
986 * function before starting the stream, otherwise the error flag will remain set
987 * until the queue is released when closing the device node.
988 */
989void vb2_queue_error(struct vb2_queue *q);
990
991/**
992 * vb2_mmap() - map video buffers into application address space.
993 * @q: pointer to &struct vb2_queue with videobuf2 queue.
994 * @vma: pointer to &struct vm_area_struct with the vma passed
995 * to the mmap file operation handler in the driver.
996 *
997 * Should be called from mmap file operation handler of a driver.
998 * This function maps one plane of one of the available video buffers to
999 * userspace. To map whole video memory allocated on reqbufs, this function
1000 * has to be called once per each plane per each buffer previously allocated.
1001 *
1002 * When the userspace application calls mmap, it passes to it an offset returned
1003 * to it earlier by the means of &v4l2_ioctl_ops->vidioc_querybuf handler.
1004 * That offset acts as a "cookie", which is then used to identify the plane
1005 * to be mapped.
1006 *
1007 * This function finds a plane with a matching offset and a mapping is performed
1008 * by the means of a provided memory operation.
1009 *
1010 * The return values from this function are intended to be directly returned
1011 * from the mmap handler in driver.
1012 */
1013int vb2_mmap(struct vb2_queue *q, struct vm_area_struct *vma);
1014
1015#ifndef CONFIG_MMU
1016/**
1017 * vb2_get_unmapped_area - map video buffers into application address space.
1018 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1019 * @addr: memory address.
1020 * @len: buffer size.
1021 * @pgoff: page offset.
1022 * @flags: memory flags.
1023 *
1024 * This function is used in noMMU platforms to propose address mapping
1025 * for a given buffer. It's intended to be used as a handler for the
1026 * &file_operations->get_unmapped_area operation.
1027 *
1028 * This is called by the mmap() syscall routines will call this
1029 * to get a proposed address for the mapping, when ``!CONFIG_MMU``.
1030 */
1031unsigned long vb2_get_unmapped_area(struct vb2_queue *q,
1032 unsigned long addr,
1033 unsigned long len,
1034 unsigned long pgoff,
1035 unsigned long flags);
1036#endif
1037
1038/**
1039 * vb2_core_poll() - implements poll syscall() logic.
1040 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1041 * @file: &struct file argument passed to the poll
1042 * file operation handler.
1043 * @wait: &poll_table wait argument passed to the poll
1044 * file operation handler.
1045 *
1046 * This function implements poll file operation handler for a driver.
1047 * For CAPTURE queues, if a buffer is ready to be dequeued, the userspace will
1048 * be informed that the file descriptor of a video device is available for
1049 * reading.
1050 * For OUTPUT queues, if a buffer is ready to be dequeued, the file descriptor
1051 * will be reported as available for writing.
1052 *
1053 * The return values from this function are intended to be directly returned
1054 * from poll handler in driver.
1055 */
1056__poll_t vb2_core_poll(struct vb2_queue *q, struct file *file,
1057 poll_table *wait);
1058
1059/**
1060 * vb2_read() - implements read() syscall logic.
1061 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1062 * @data: pointed to target userspace buffer
1063 * @count: number of bytes to read
1064 * @ppos: file handle position tracking pointer
1065 * @nonblock: mode selector (1 means blocking calls, 0 means nonblocking)
1066 */
1067size_t vb2_read(struct vb2_queue *q, char __user *data, size_t count,
1068 loff_t *ppos, int nonblock);
1069/**
1070 * vb2_write() - implements write() syscall logic.
1071 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1072 * @data: pointed to target userspace buffer
1073 * @count: number of bytes to write
1074 * @ppos: file handle position tracking pointer
1075 * @nonblock: mode selector (1 means blocking calls, 0 means nonblocking)
1076 */
1077size_t vb2_write(struct vb2_queue *q, const char __user *data, size_t count,
1078 loff_t *ppos, int nonblock);
1079
1080/**
1081 * typedef vb2_thread_fnc - callback function for use with vb2_thread.
1082 *
1083 * @vb: pointer to struct &vb2_buffer.
1084 * @priv: pointer to a private data.
1085 *
1086 * This is called whenever a buffer is dequeued in the thread.
1087 */
1088typedef int (*vb2_thread_fnc)(struct vb2_buffer *vb, void *priv);
1089
1090/**
1091 * vb2_thread_start() - start a thread for the given queue.
1092 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1093 * @fnc: &vb2_thread_fnc callback function.
1094 * @priv: priv pointer passed to the callback function.
1095 * @thread_name:the name of the thread. This will be prefixed with "vb2-".
1096 *
1097 * This starts a thread that will queue and dequeue until an error occurs
1098 * or vb2_thread_stop() is called.
1099 *
1100 * .. attention::
1101 *
1102 * This function should not be used for anything else but the videobuf2-dvb
1103 * support. If you think you have another good use-case for this, then please
1104 * contact the linux-media mailing list first.
1105 */
1106int vb2_thread_start(struct vb2_queue *q, vb2_thread_fnc fnc, void *priv,
1107 const char *thread_name);
1108
1109/**
1110 * vb2_thread_stop() - stop the thread for the given queue.
1111 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1112 */
1113int vb2_thread_stop(struct vb2_queue *q);
1114
1115/**
1116 * vb2_is_streaming() - return streaming status of the queue.
1117 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1118 */
1119static inline bool vb2_is_streaming(struct vb2_queue *q)
1120{
1121 return q->streaming;
1122}
1123
1124/**
1125 * vb2_fileio_is_active() - return true if fileio is active.
1126 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1127 *
1128 * This returns true if read() or write() is used to stream the data
1129 * as opposed to stream I/O. This is almost never an important distinction,
1130 * except in rare cases. One such case is that using read() or write() to
1131 * stream a format using %V4L2_FIELD_ALTERNATE is not allowed since there
1132 * is no way you can pass the field information of each buffer to/from
1133 * userspace. A driver that supports this field format should check for
1134 * this in the &vb2_ops->queue_setup op and reject it if this function returns
1135 * true.
1136 */
1137static inline bool vb2_fileio_is_active(struct vb2_queue *q)
1138{
1139 return q->fileio;
1140}
1141
1142/**
1143 * vb2_is_busy() - return busy status of the queue.
1144 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1145 *
1146 * This function checks if queue has any buffers allocated.
1147 */
1148static inline bool vb2_is_busy(struct vb2_queue *q)
1149{
1150 return (q->num_buffers > 0);
1151}
1152
1153/**
1154 * vb2_get_drv_priv() - return driver private data associated with the queue.
1155 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1156 */
1157static inline void *vb2_get_drv_priv(struct vb2_queue *q)
1158{
1159 return q->drv_priv;
1160}
1161
1162/**
1163 * vb2_set_plane_payload() - set bytesused for the plane @plane_no.
1164 * @vb: pointer to &struct vb2_buffer to which the plane in
1165 * question belongs to.
1166 * @plane_no: plane number for which payload should be set.
1167 * @size: payload in bytes.
1168 */
1169static inline void vb2_set_plane_payload(struct vb2_buffer *vb,
1170 unsigned int plane_no, unsigned long size)
1171{
1172 /*
1173 * size must never be larger than the buffer length, so
1174 * warn and clamp to the buffer length if that's the case.
1175 */
1176 if (plane_no < vb->num_planes) {
1177 if (WARN_ON_ONCE(size > vb->planes[plane_no].length))
1178 size = vb->planes[plane_no].length;
1179 vb->planes[plane_no].bytesused = size;
1180 }
1181}
1182
1183/**
1184 * vb2_get_plane_payload() - get bytesused for the plane plane_no
1185 * @vb: pointer to &struct vb2_buffer to which the plane in
1186 * question belongs to.
1187 * @plane_no: plane number for which payload should be set.
1188 */
1189static inline unsigned long vb2_get_plane_payload(struct vb2_buffer *vb,
1190 unsigned int plane_no)
1191{
1192 if (plane_no < vb->num_planes)
1193 return vb->planes[plane_no].bytesused;
1194 return 0;
1195}
1196
1197/**
1198 * vb2_plane_size() - return plane size in bytes.
1199 * @vb: pointer to &struct vb2_buffer to which the plane in
1200 * question belongs to.
1201 * @plane_no: plane number for which size should be returned.
1202 */
1203static inline unsigned long
1204vb2_plane_size(struct vb2_buffer *vb, unsigned int plane_no)
1205{
1206 if (plane_no < vb->num_planes)
1207 return vb->planes[plane_no].length;
1208 return 0;
1209}
1210
1211/**
1212 * vb2_start_streaming_called() - return streaming status of driver.
1213 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1214 */
1215static inline bool vb2_start_streaming_called(struct vb2_queue *q)
1216{
1217 return q->start_streaming_called;
1218}
1219
1220/**
1221 * vb2_clear_last_buffer_dequeued() - clear last buffer dequeued flag of queue.
1222 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1223 */
1224static inline void vb2_clear_last_buffer_dequeued(struct vb2_queue *q)
1225{
1226 q->last_buffer_dequeued = false;
1227}
1228
1229/**
1230 * vb2_get_buffer() - get a buffer from a queue
1231 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1232 * @index: buffer index
1233 *
1234 * This function obtains a buffer from a queue, by its index.
1235 * Keep in mind that there is no refcounting involved in this
1236 * operation, so the buffer lifetime should be taken into
1237 * consideration.
1238 */
1239static inline struct vb2_buffer *vb2_get_buffer(struct vb2_queue *q,
1240 unsigned int index)
1241{
1242 if (index < q->num_buffers)
1243 return q->bufs[index];
1244 return NULL;
1245}
1246
1247/*
1248 * The following functions are not part of the vb2 core API, but are useful
1249 * functions for videobuf2-*.
1250 */
1251
1252/**
1253 * vb2_buffer_in_use() - return true if the buffer is in use and
1254 * the queue cannot be freed (by the means of VIDIOC_REQBUFS(0)) call.
1255 *
1256 * @vb: buffer for which plane size should be returned.
1257 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1258 */
1259bool vb2_buffer_in_use(struct vb2_queue *q, struct vb2_buffer *vb);
1260
1261/**
1262 * vb2_verify_memory_type() - Check whether the memory type and buffer type
1263 * passed to a buffer operation are compatible with the queue.
1264 *
1265 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1266 * @memory: memory model, as defined by enum &vb2_memory.
1267 * @type: private buffer type whose content is defined by the vb2-core
1268 * caller. For example, for V4L2, it should match
1269 * the types defined on enum &v4l2_buf_type.
1270 */
1271int vb2_verify_memory_type(struct vb2_queue *q,
1272 enum vb2_memory memory, unsigned int type);
1273
1274/**
1275 * vb2_request_object_is_buffer() - return true if the object is a buffer
1276 *
1277 * @obj: the request object.
1278 */
1279bool vb2_request_object_is_buffer(struct media_request_object *obj);
1280
1281/**
1282 * vb2_request_buffer_cnt() - return the number of buffers in the request
1283 *
1284 * @req: the request.
1285 */
1286unsigned int vb2_request_buffer_cnt(struct media_request *req);
1287
1288#endif /* _MEDIA_VIDEOBUF2_CORE_H */
1289

source code of linux/include/media/videobuf2-core.h