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 * @prepare: called every time the buffer is passed from userspace to the
76 * driver, useful for cache synchronisation, optional.
77 * @finish: called every time the buffer is passed back from the driver
78 * to the userspace, also optional.
79 * @attach_dmabuf: attach a shared &struct dma_buf for a hardware operation;
80 * used for DMABUF memory types; dev is the alloc device
81 * dbuf is the shared dma_buf; returns ERR_PTR() on failure;
82 * allocator private per-buffer structure on success;
83 * this needs to be used for further accesses to the buffer.
84 * @detach_dmabuf: inform the exporter of the buffer that the current DMABUF
85 * buffer is no longer used; the @buf_priv argument is the
86 * allocator private per-buffer structure previously returned
87 * from the attach_dmabuf callback.
88 * @map_dmabuf: request for access to the dmabuf from allocator; the allocator
89 * of dmabuf is informed that this driver is going to use the
90 * dmabuf.
91 * @unmap_dmabuf: releases access control to the dmabuf - allocator is notified
92 * that this driver is done using the dmabuf for now.
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 * @dbuf_duplicated: boolean to show whether dbuf is duplicated with a
158 * previous plane of the buffer.
159 * @bytesused: number of bytes occupied by data in the plane (payload).
160 * @length: size of this plane (NOT the payload) in bytes. The maximum
161 * valid size is MAX_UINT - PAGE_SIZE.
162 * @min_length: minimum required size of this plane (NOT the payload) in bytes.
163 * @length is always greater or equal to @min_length, and like
164 * @length, it is limited to MAX_UINT - PAGE_SIZE.
165 * @m: Union with memtype-specific data.
166 * @m.offset: when memory in the associated struct vb2_buffer is
167 * %VB2_MEMORY_MMAP, equals the offset from the start of
168 * the device memory for this plane (or is a "cookie" that
169 * should be passed to mmap() called on the video node).
170 * @m.userptr: when memory is %VB2_MEMORY_USERPTR, a userspace pointer
171 * pointing to this plane.
172 * @m.fd: when memory is %VB2_MEMORY_DMABUF, a userspace file
173 * descriptor associated with this plane.
174 * @data_offset: offset in the plane to the start of data; usually 0,
175 * unless there is a header in front of the data.
176 *
177 * Should contain enough information to be able to cover all the fields
178 * of &struct v4l2_plane at videodev2.h.
179 */
180struct vb2_plane {
181 void *mem_priv;
182 struct dma_buf *dbuf;
183 unsigned int dbuf_mapped;
184 bool dbuf_duplicated;
185 unsigned int bytesused;
186 unsigned int length;
187 unsigned int min_length;
188 union {
189 unsigned int offset;
190 unsigned long userptr;
191 int fd;
192 } m;
193 unsigned int data_offset;
194};
195
196/**
197 * enum vb2_io_modes - queue access methods.
198 * @VB2_MMAP: driver supports MMAP with streaming API.
199 * @VB2_USERPTR: driver supports USERPTR with streaming API.
200 * @VB2_READ: driver supports read() style access.
201 * @VB2_WRITE: driver supports write() style access.
202 * @VB2_DMABUF: driver supports DMABUF with streaming API.
203 */
204enum vb2_io_modes {
205 VB2_MMAP = BIT(0),
206 VB2_USERPTR = BIT(1),
207 VB2_READ = BIT(2),
208 VB2_WRITE = BIT(3),
209 VB2_DMABUF = BIT(4),
210};
211
212/**
213 * enum vb2_buffer_state - current video buffer state.
214 * @VB2_BUF_STATE_DEQUEUED: buffer under userspace control.
215 * @VB2_BUF_STATE_IN_REQUEST: buffer is queued in media request.
216 * @VB2_BUF_STATE_PREPARING: buffer is being prepared in videobuf2.
217 * @VB2_BUF_STATE_QUEUED: buffer queued in videobuf2, but not in driver.
218 * @VB2_BUF_STATE_ACTIVE: buffer queued in driver and possibly used
219 * in a hardware operation.
220 * @VB2_BUF_STATE_DONE: buffer returned from driver to videobuf2, but
221 * not yet dequeued to userspace.
222 * @VB2_BUF_STATE_ERROR: same as above, but the operation on the buffer
223 * has ended with an error, which will be reported
224 * to the userspace when it is dequeued.
225 */
226enum vb2_buffer_state {
227 VB2_BUF_STATE_DEQUEUED,
228 VB2_BUF_STATE_IN_REQUEST,
229 VB2_BUF_STATE_PREPARING,
230 VB2_BUF_STATE_QUEUED,
231 VB2_BUF_STATE_ACTIVE,
232 VB2_BUF_STATE_DONE,
233 VB2_BUF_STATE_ERROR,
234};
235
236struct vb2_queue;
237
238/**
239 * struct vb2_buffer - represents a video buffer.
240 * @vb2_queue: pointer to &struct vb2_queue with the queue to
241 * which this driver belongs.
242 * @index: id number of the buffer.
243 * @type: buffer type.
244 * @memory: the method, in which the actual data is passed.
245 * @num_planes: number of planes in the buffer
246 * on an internal driver queue.
247 * @timestamp: frame timestamp in ns.
248 * @request: the request this buffer is associated with.
249 * @req_obj: used to bind this buffer to a request. This
250 * request object has a refcount.
251 */
252struct vb2_buffer {
253 struct vb2_queue *vb2_queue;
254 unsigned int index;
255 unsigned int type;
256 unsigned int memory;
257 unsigned int num_planes;
258 u64 timestamp;
259 struct media_request *request;
260 struct media_request_object req_obj;
261
262 /* private: internal use only
263 *
264 * state: current buffer state; do not change
265 * synced: this buffer has been synced for DMA, i.e. the
266 * 'prepare' memop was called. It is cleared again
267 * after the 'finish' memop is called.
268 * prepared: this buffer has been prepared, i.e. the
269 * buf_prepare op was called. It is cleared again
270 * after the 'buf_finish' op is called.
271 * copied_timestamp: the timestamp of this capture buffer was copied
272 * from an output buffer.
273 * skip_cache_sync_on_prepare: when set buffer's ->prepare() function
274 * skips cache sync/invalidation.
275 * skip_cache_sync_on_finish: when set buffer's ->finish() function
276 * skips cache sync/invalidation.
277 * planes: per-plane information; do not change
278 * queued_entry: entry on the queued buffers list, which holds
279 * all buffers queued from userspace
280 * done_entry: entry on the list that stores all buffers ready
281 * to be dequeued to userspace
282 */
283 enum vb2_buffer_state state;
284 unsigned int synced:1;
285 unsigned int prepared:1;
286 unsigned int copied_timestamp:1;
287 unsigned int skip_cache_sync_on_prepare:1;
288 unsigned int skip_cache_sync_on_finish:1;
289
290 struct vb2_plane planes[VB2_MAX_PLANES];
291 struct list_head queued_entry;
292 struct list_head done_entry;
293#ifdef CONFIG_VIDEO_ADV_DEBUG
294 /*
295 * Counters for how often these buffer-related ops are
296 * called. Used to check for unbalanced ops.
297 */
298 u32 cnt_mem_alloc;
299 u32 cnt_mem_put;
300 u32 cnt_mem_get_dmabuf;
301 u32 cnt_mem_get_userptr;
302 u32 cnt_mem_put_userptr;
303 u32 cnt_mem_prepare;
304 u32 cnt_mem_finish;
305 u32 cnt_mem_attach_dmabuf;
306 u32 cnt_mem_detach_dmabuf;
307 u32 cnt_mem_map_dmabuf;
308 u32 cnt_mem_unmap_dmabuf;
309 u32 cnt_mem_vaddr;
310 u32 cnt_mem_cookie;
311 u32 cnt_mem_num_users;
312 u32 cnt_mem_mmap;
313
314 u32 cnt_buf_out_validate;
315 u32 cnt_buf_init;
316 u32 cnt_buf_prepare;
317 u32 cnt_buf_finish;
318 u32 cnt_buf_cleanup;
319 u32 cnt_buf_queue;
320 u32 cnt_buf_request_complete;
321
322 /* This counts the number of calls to vb2_buffer_done() */
323 u32 cnt_buf_done;
324#endif
325};
326
327/**
328 * struct vb2_ops - driver-specific callbacks.
329 *
330 * These operations are not called from interrupt context except where
331 * mentioned specifically.
332 *
333 * @queue_setup: called from VIDIOC_REQBUFS() and VIDIOC_CREATE_BUFS()
334 * handlers before memory allocation. It can be called
335 * twice: if the original number of requested buffers
336 * could not be allocated, then it will be called a
337 * second time with the actually allocated number of
338 * buffers to verify if that is OK.
339 * The driver should return the required number of buffers
340 * in \*num_buffers, the required number of planes per
341 * buffer in \*num_planes, the size of each plane should be
342 * set in the sizes\[\] array and optional per-plane
343 * allocator specific device in the alloc_devs\[\] array.
344 * When called from VIDIOC_REQBUFS(), \*num_planes == 0,
345 * the driver has to use the currently configured format to
346 * determine the plane sizes and \*num_buffers is the total
347 * number of buffers that are being allocated. When called
348 * from VIDIOC_CREATE_BUFS(), \*num_planes != 0 and it
349 * describes the requested number of planes and sizes\[\]
350 * contains the requested plane sizes. In this case
351 * \*num_buffers are being allocated additionally to
352 * the buffers already allocated. If either \*num_planes
353 * or the requested sizes are invalid callback must return %-EINVAL.
354 * @wait_prepare: release any locks taken while calling vb2 functions;
355 * it is called before an ioctl needs to wait for a new
356 * buffer to arrive; required to avoid a deadlock in
357 * blocking access type.
358 * @wait_finish: reacquire all locks released in the previous callback;
359 * required to continue operation after sleeping while
360 * waiting for a new buffer to arrive.
361 * @buf_out_validate: called when the output buffer is prepared or queued
362 * to a request; drivers can use this to validate
363 * userspace-provided information; this is required only
364 * for OUTPUT queues.
365 * @buf_init: called once after allocating a buffer (in MMAP case)
366 * or after acquiring a new USERPTR buffer; drivers may
367 * perform additional buffer-related initialization;
368 * initialization failure (return != 0) will prevent
369 * queue setup from completing successfully; optional.
370 * @buf_prepare: called every time the buffer is queued from userspace
371 * and from the VIDIOC_PREPARE_BUF() ioctl; drivers may
372 * perform any initialization required before each
373 * hardware operation in this callback; drivers can
374 * access/modify the buffer here as it is still synced for
375 * the CPU; drivers that support VIDIOC_CREATE_BUFS() must
376 * also validate the buffer size; if an error is returned,
377 * the buffer will not be queued in driver; optional.
378 * @buf_finish: called before every dequeue of the buffer back to
379 * userspace; the buffer is synced for the CPU, so drivers
380 * can access/modify the buffer contents; drivers may
381 * perform any operations required before userspace
382 * accesses the buffer; optional. The buffer state can be
383 * one of the following: %DONE and %ERROR occur while
384 * streaming is in progress, and the %PREPARED state occurs
385 * when the queue has been canceled and all pending
386 * buffers are being returned to their default %DEQUEUED
387 * state. Typically you only have to do something if the
388 * state is %VB2_BUF_STATE_DONE, since in all other cases
389 * the buffer contents will be ignored anyway.
390 * @buf_cleanup: called once before the buffer is freed; drivers may
391 * perform any additional cleanup; optional.
392 * @prepare_streaming: called once to prepare for 'streaming' state; this is
393 * where validation can be done to verify everything is
394 * okay and streaming resources can be claimed. It is
395 * called when the VIDIOC_STREAMON ioctl is called. The
396 * actual streaming starts when @start_streaming is called.
397 * Optional.
398 * @start_streaming: called once to enter 'streaming' state; the driver may
399 * receive buffers with @buf_queue callback
400 * before @start_streaming is called; the driver gets the
401 * number of already queued buffers in count parameter;
402 * driver can return an error if hardware fails, in that
403 * case all buffers that have been already given by
404 * the @buf_queue callback are to be returned by the driver
405 * by calling vb2_buffer_done() with %VB2_BUF_STATE_QUEUED.
406 * If you need a minimum number of buffers before you can
407 * start streaming, then set
408 * &vb2_queue->min_queued_buffers. If that is non-zero
409 * then @start_streaming won't be called until at least
410 * that many buffers have been queued up by userspace.
411 * @stop_streaming: called when 'streaming' state must be disabled; driver
412 * should stop any DMA transactions or wait until they
413 * finish and give back all buffers it got from &buf_queue
414 * callback by calling vb2_buffer_done() with either
415 * %VB2_BUF_STATE_DONE or %VB2_BUF_STATE_ERROR; may use
416 * vb2_wait_for_all_buffers() function
417 * @unprepare_streaming:called as counterpart to @prepare_streaming; any claimed
418 * streaming resources can be released here. It is
419 * called when the VIDIOC_STREAMOFF ioctls is called or
420 * when the streaming filehandle is closed. Optional.
421 * @buf_queue: passes buffer vb to the driver; driver may start
422 * hardware operation on this buffer; driver should give
423 * the buffer back by calling vb2_buffer_done() function;
424 * it is always called after calling VIDIOC_STREAMON()
425 * ioctl; might be called before @start_streaming callback
426 * if user pre-queued buffers before calling
427 * VIDIOC_STREAMON().
428 * @buf_request_complete: a buffer that was never queued to the driver but is
429 * associated with a queued request was canceled.
430 * The driver will have to mark associated objects in the
431 * request as completed; required if requests are
432 * supported.
433 */
434struct vb2_ops {
435 int (*queue_setup)(struct vb2_queue *q,
436 unsigned int *num_buffers, unsigned int *num_planes,
437 unsigned int sizes[], struct device *alloc_devs[]);
438
439 void (*wait_prepare)(struct vb2_queue *q);
440 void (*wait_finish)(struct vb2_queue *q);
441
442 int (*buf_out_validate)(struct vb2_buffer *vb);
443 int (*buf_init)(struct vb2_buffer *vb);
444 int (*buf_prepare)(struct vb2_buffer *vb);
445 void (*buf_finish)(struct vb2_buffer *vb);
446 void (*buf_cleanup)(struct vb2_buffer *vb);
447
448 int (*prepare_streaming)(struct vb2_queue *q);
449 int (*start_streaming)(struct vb2_queue *q, unsigned int count);
450 void (*stop_streaming)(struct vb2_queue *q);
451 void (*unprepare_streaming)(struct vb2_queue *q);
452
453 void (*buf_queue)(struct vb2_buffer *vb);
454
455 void (*buf_request_complete)(struct vb2_buffer *vb);
456};
457
458/**
459 * struct vb2_buf_ops - driver-specific callbacks.
460 *
461 * @verify_planes_array: Verify that a given user space structure contains
462 * enough planes for the buffer. This is called
463 * for each dequeued buffer.
464 * @init_buffer: given a &vb2_buffer initialize the extra data after
465 * struct vb2_buffer.
466 * For V4L2 this is a &struct vb2_v4l2_buffer.
467 * @fill_user_buffer: given a &vb2_buffer fill in the userspace structure.
468 * For V4L2 this is a &struct v4l2_buffer.
469 * @fill_vb2_buffer: given a userspace structure, fill in the &vb2_buffer.
470 * If the userspace structure is invalid, then this op
471 * will return an error.
472 * @copy_timestamp: copy the timestamp from a userspace structure to
473 * the &struct vb2_buffer.
474 */
475struct vb2_buf_ops {
476 int (*verify_planes_array)(struct vb2_buffer *vb, const void *pb);
477 void (*init_buffer)(struct vb2_buffer *vb);
478 void (*fill_user_buffer)(struct vb2_buffer *vb, void *pb);
479 int (*fill_vb2_buffer)(struct vb2_buffer *vb, struct vb2_plane *planes);
480 void (*copy_timestamp)(struct vb2_buffer *vb, const void *pb);
481};
482
483/**
484 * struct vb2_queue - a videobuf2 queue.
485 *
486 * @type: private buffer type whose content is defined by the vb2-core
487 * caller. For example, for V4L2, it should match
488 * the types defined on &enum v4l2_buf_type.
489 * @io_modes: supported io methods (see &enum vb2_io_modes).
490 * @dev: device to use for the default allocation context if the driver
491 * doesn't fill in the @alloc_devs array.
492 * @dma_attrs: DMA attributes to use for the DMA.
493 * @bidirectional: when this flag is set the DMA direction for the buffers of
494 * this queue will be overridden with %DMA_BIDIRECTIONAL direction.
495 * This is useful in cases where the hardware (firmware) writes to
496 * a buffer which is mapped as read (%DMA_TO_DEVICE), or reads from
497 * buffer which is mapped for write (%DMA_FROM_DEVICE) in order
498 * to satisfy some internal hardware restrictions or adds a padding
499 * needed by the processing algorithm. In case the DMA mapping is
500 * not bidirectional but the hardware (firmware) trying to access
501 * the buffer (in the opposite direction) this could lead to an
502 * IOMMU protection faults.
503 * @fileio_read_once: report EOF after reading the first buffer
504 * @fileio_write_immediately: queue buffer after each write() call
505 * @allow_zero_bytesused: allow bytesused == 0 to be passed to the driver
506 * @quirk_poll_must_check_waiting_for_buffers: Return %EPOLLERR at poll when QBUF
507 * has not been called. This is a vb1 idiom that has been adopted
508 * also by vb2.
509 * @supports_requests: this queue supports the Request API.
510 * @requires_requests: this queue requires the Request API. If this is set to 1,
511 * then supports_requests must be set to 1 as well.
512 * @uses_qbuf: qbuf was used directly for this queue. Set to 1 the first
513 * time this is called. Set to 0 when the queue is canceled.
514 * If this is 1, then you cannot queue buffers from a request.
515 * @uses_requests: requests are used for this queue. Set to 1 the first time
516 * a request is queued. Set to 0 when the queue is canceled.
517 * If this is 1, then you cannot queue buffers directly.
518 * @allow_cache_hints: when set user-space can pass cache management hints in
519 * order to skip cache flush/invalidation on ->prepare() or/and
520 * ->finish().
521 * @non_coherent_mem: when set queue will attempt to allocate buffers using
522 * non-coherent memory.
523 * @lock: pointer to a mutex that protects the &struct vb2_queue. The
524 * driver can set this to a mutex to let the v4l2 core serialize
525 * the queuing ioctls. If the driver wants to handle locking
526 * itself, then this should be set to NULL. This lock is not used
527 * by the videobuf2 core API.
528 * @owner: The filehandle that 'owns' the buffers, i.e. the filehandle
529 * that called reqbufs, create_buffers or started fileio.
530 * This field is not used by the videobuf2 core API, but it allows
531 * drivers to easily associate an owner filehandle with the queue.
532 * @ops: driver-specific callbacks
533 * @mem_ops: memory allocator specific callbacks
534 * @buf_ops: callbacks to deliver buffer information.
535 * between user-space and kernel-space.
536 * @drv_priv: driver private data.
537 * @subsystem_flags: Flags specific to the subsystem (V4L2/DVB/etc.). Not used
538 * by the vb2 core.
539 * @buf_struct_size: size of the driver-specific buffer structure;
540 * "0" indicates the driver doesn't want to use a custom buffer
541 * structure type. In that case a subsystem-specific struct
542 * will be used (in the case of V4L2 that is
543 * ``sizeof(struct vb2_v4l2_buffer)``). The first field of the
544 * driver-specific buffer structure must be the subsystem-specific
545 * struct (vb2_v4l2_buffer in the case of V4L2).
546 * @timestamp_flags: Timestamp flags; ``V4L2_BUF_FLAG_TIMESTAMP_*`` and
547 * ``V4L2_BUF_FLAG_TSTAMP_SRC_*``
548 * @gfp_flags: additional gfp flags used when allocating the buffers.
549 * Typically this is 0, but it may be e.g. %GFP_DMA or %__GFP_DMA32
550 * to force the buffer allocation to a specific memory zone.
551 * @min_queued_buffers: the minimum number of queued buffers needed before
552 * @start_streaming can be called. Used when a DMA engine
553 * cannot be started unless at least this number of buffers
554 * have been queued into the driver.
555 * VIDIOC_REQBUFS will ensure at least @min_queued_buffers + 1
556 * buffers will be allocated. Note that VIDIOC_CREATE_BUFS will not
557 * modify the requested buffer count.
558 * @min_reqbufs_allocation: the minimum number of buffers to be allocated when
559 * calling VIDIOC_REQBUFS. Note that VIDIOC_CREATE_BUFS will *not*
560 * modify the requested buffer count and does not use this field.
561 * Drivers can set this if there has to be a certain number of
562 * buffers available for the hardware to work effectively.
563 * This allows calling VIDIOC_REQBUFS with a buffer count of 1 and
564 * it will be automatically adjusted to a workable buffer count.
565 * If set, then @min_reqbufs_allocation must be larger than
566 * @min_queued_buffers + 1.
567 * If this field is > 3, then it is highly recommended that the
568 * driver implements the V4L2_CID_MIN_BUFFERS_FOR_CAPTURE/OUTPUT
569 * control.
570 * @alloc_devs: &struct device memory type/allocator-specific per-plane device
571 */
572/*
573 * Private elements (won't appear at the uAPI book):
574 * @mmap_lock: private mutex used when buffers are allocated/freed/mmapped
575 * @memory: current memory type used
576 * @dma_dir: DMA mapping direction.
577 * @bufs: videobuf2 buffer structures. If it is non-NULL then
578 * bufs_bitmap is also non-NULL.
579 * @bufs_bitmap: bitmap tracking whether each bufs[] entry is used
580 * @max_num_buffers: upper limit of number of allocated/used buffers.
581 * If set to 0 v4l2 core will change it VB2_MAX_FRAME
582 * for backward compatibility.
583 * @queued_list: list of buffers currently queued from userspace
584 * @queued_count: number of buffers queued and ready for streaming.
585 * @owned_by_drv_count: number of buffers owned by the driver
586 * @done_list: list of buffers ready to be dequeued to userspace
587 * @done_lock: lock to protect done_list list
588 * @done_wq: waitqueue for processes waiting for buffers ready to be dequeued
589 * @streaming: current streaming state
590 * @start_streaming_called: @start_streaming was called successfully and we
591 * started streaming.
592 * @error: a fatal error occurred on the queue
593 * @waiting_for_buffers: used in poll() to check if vb2 is still waiting for
594 * buffers. Only set for capture queues if qbuf has not yet been
595 * called since poll() needs to return %EPOLLERR in that situation.
596 * @waiting_in_dqbuf: set by the core for the duration of a blocking DQBUF, when
597 * it has to wait for a buffer to become available with vb2_queue->lock
598 * released. Used to prevent destroying the queue by other threads.
599 * @is_multiplanar: set if buffer type is multiplanar
600 * @is_output: set if buffer type is output
601 * @is_busy: set if at least one buffer has been allocated at some time.
602 * @copy_timestamp: set if vb2-core should set timestamps
603 * @last_buffer_dequeued: used in poll() and DQBUF to immediately return if the
604 * last decoded buffer was already dequeued. Set for capture queues
605 * when a buffer with the %V4L2_BUF_FLAG_LAST is dequeued.
606 * @fileio: file io emulator internal data, used only if emulator is active
607 * @threadio: thread io internal data, used only if thread is active
608 * @name: queue name, used for logging purpose. Initialized automatically
609 * if left empty by drivers.
610 */
611struct vb2_queue {
612 unsigned int type;
613 unsigned int io_modes;
614 struct device *dev;
615 unsigned long dma_attrs;
616 unsigned int bidirectional:1;
617 unsigned int fileio_read_once:1;
618 unsigned int fileio_write_immediately:1;
619 unsigned int allow_zero_bytesused:1;
620 unsigned int quirk_poll_must_check_waiting_for_buffers:1;
621 unsigned int supports_requests:1;
622 unsigned int requires_requests:1;
623 unsigned int uses_qbuf:1;
624 unsigned int uses_requests:1;
625 unsigned int allow_cache_hints:1;
626 unsigned int non_coherent_mem:1;
627
628 struct mutex *lock;
629 void *owner;
630
631 const struct vb2_ops *ops;
632 const struct vb2_mem_ops *mem_ops;
633 const struct vb2_buf_ops *buf_ops;
634
635 void *drv_priv;
636 u32 subsystem_flags;
637 unsigned int buf_struct_size;
638 u32 timestamp_flags;
639 gfp_t gfp_flags;
640 u32 min_queued_buffers;
641 u32 min_reqbufs_allocation;
642
643 struct device *alloc_devs[VB2_MAX_PLANES];
644
645 /* private: internal use only */
646 struct mutex mmap_lock;
647 unsigned int memory;
648 enum dma_data_direction dma_dir;
649 struct vb2_buffer **bufs;
650 unsigned long *bufs_bitmap;
651 unsigned int max_num_buffers;
652
653 struct list_head queued_list;
654 unsigned int queued_count;
655
656 atomic_t owned_by_drv_count;
657 struct list_head done_list;
658 spinlock_t done_lock;
659 wait_queue_head_t done_wq;
660
661 unsigned int streaming:1;
662 unsigned int start_streaming_called:1;
663 unsigned int error:1;
664 unsigned int waiting_for_buffers:1;
665 unsigned int waiting_in_dqbuf:1;
666 unsigned int is_multiplanar:1;
667 unsigned int is_output:1;
668 unsigned int is_busy:1;
669 unsigned int copy_timestamp:1;
670 unsigned int last_buffer_dequeued:1;
671
672 struct vb2_fileio_data *fileio;
673 struct vb2_threadio_data *threadio;
674
675 char name[32];
676
677#ifdef CONFIG_VIDEO_ADV_DEBUG
678 /*
679 * Counters for how often these queue-related ops are
680 * called. Used to check for unbalanced ops.
681 */
682 u32 cnt_queue_setup;
683 u32 cnt_wait_prepare;
684 u32 cnt_wait_finish;
685 u32 cnt_prepare_streaming;
686 u32 cnt_start_streaming;
687 u32 cnt_stop_streaming;
688 u32 cnt_unprepare_streaming;
689#endif
690};
691
692/**
693 * vb2_queue_allows_cache_hints() - Return true if the queue allows cache
694 * and memory consistency hints.
695 *
696 * @q: pointer to &struct vb2_queue with videobuf2 queue
697 */
698static inline bool vb2_queue_allows_cache_hints(struct vb2_queue *q)
699{
700 return q->allow_cache_hints && q->memory == VB2_MEMORY_MMAP;
701}
702
703/**
704 * vb2_plane_vaddr() - Return a kernel virtual address of a given plane.
705 * @vb: pointer to &struct vb2_buffer to which the plane in
706 * question belongs to.
707 * @plane_no: plane number for which the address is to be returned.
708 *
709 * This function returns a kernel virtual address of a given plane if
710 * such a mapping exist, NULL otherwise.
711 */
712void *vb2_plane_vaddr(struct vb2_buffer *vb, unsigned int plane_no);
713
714/**
715 * vb2_plane_cookie() - Return allocator specific cookie for the given plane.
716 * @vb: pointer to &struct vb2_buffer to which the plane in
717 * question belongs to.
718 * @plane_no: plane number for which the cookie is to be returned.
719 *
720 * This function returns an allocator specific cookie for a given plane if
721 * available, NULL otherwise. The allocator should provide some simple static
722 * inline function, which would convert this cookie to the allocator specific
723 * type that can be used directly by the driver to access the buffer. This can
724 * be for example physical address, pointer to scatter list or IOMMU mapping.
725 */
726void *vb2_plane_cookie(struct vb2_buffer *vb, unsigned int plane_no);
727
728/**
729 * vb2_buffer_done() - inform videobuf2 that an operation on a buffer
730 * is finished.
731 * @vb: pointer to &struct vb2_buffer to be used.
732 * @state: state of the buffer, as defined by &enum vb2_buffer_state.
733 * Either %VB2_BUF_STATE_DONE if the operation finished
734 * successfully, %VB2_BUF_STATE_ERROR if the operation finished
735 * with an error or %VB2_BUF_STATE_QUEUED.
736 *
737 * This function should be called by the driver after a hardware operation on
738 * a buffer is finished and the buffer may be returned to userspace. The driver
739 * cannot use this buffer anymore until it is queued back to it by videobuf
740 * by the means of &vb2_ops->buf_queue callback. Only buffers previously queued
741 * to the driver by &vb2_ops->buf_queue can be passed to this function.
742 *
743 * While streaming a buffer can only be returned in state DONE or ERROR.
744 * The &vb2_ops->start_streaming op can also return them in case the DMA engine
745 * cannot be started for some reason. In that case the buffers should be
746 * returned with state QUEUED to put them back into the queue.
747 */
748void vb2_buffer_done(struct vb2_buffer *vb, enum vb2_buffer_state state);
749
750/**
751 * vb2_discard_done() - discard all buffers marked as DONE.
752 * @q: pointer to &struct vb2_queue with videobuf2 queue.
753 *
754 * This function is intended to be used with suspend/resume operations. It
755 * discards all 'done' buffers as they would be too old to be requested after
756 * resume.
757 *
758 * Drivers must stop the hardware and synchronize with interrupt handlers and/or
759 * delayed works before calling this function to make sure no buffer will be
760 * touched by the driver and/or hardware.
761 */
762void vb2_discard_done(struct vb2_queue *q);
763
764/**
765 * vb2_wait_for_all_buffers() - wait until all buffers are given back to vb2.
766 * @q: pointer to &struct vb2_queue with videobuf2 queue.
767 *
768 * This function will wait until all buffers that have been given to the driver
769 * by &vb2_ops->buf_queue are given back to vb2 with vb2_buffer_done(). It
770 * doesn't call &vb2_ops->wait_prepare/&vb2_ops->wait_finish pair.
771 * It is intended to be called with all locks taken, for example from
772 * &vb2_ops->stop_streaming callback.
773 */
774int vb2_wait_for_all_buffers(struct vb2_queue *q);
775
776/**
777 * vb2_core_querybuf() - query video buffer information.
778 * @q: pointer to &struct vb2_queue with videobuf2 queue.
779 * @vb: pointer to struct &vb2_buffer.
780 * @pb: buffer struct passed from userspace.
781 *
782 * Videobuf2 core helper to implement VIDIOC_QUERYBUF() operation. It is called
783 * internally by VB2 by an API-specific handler, like ``videobuf2-v4l2.h``.
784 *
785 * The passed buffer should have been verified.
786 *
787 * This function fills the relevant information for the userspace.
788 *
789 * Return: returns zero on success; an error code otherwise.
790 */
791void vb2_core_querybuf(struct vb2_queue *q, struct vb2_buffer *vb, void *pb);
792
793/**
794 * vb2_core_reqbufs() - Initiate streaming.
795 * @q: pointer to &struct vb2_queue with videobuf2 queue.
796 * @memory: memory type, as defined by &enum vb2_memory.
797 * @flags: auxiliary queue/buffer management flags. Currently, the only
798 * used flag is %V4L2_MEMORY_FLAG_NON_COHERENT.
799 * @count: requested buffer count.
800 *
801 * Videobuf2 core helper to implement VIDIOC_REQBUF() operation. It is called
802 * internally by VB2 by an API-specific handler, like ``videobuf2-v4l2.h``.
803 *
804 * This function:
805 *
806 * #) verifies streaming parameters passed from the userspace;
807 * #) sets up the queue;
808 * #) negotiates number of buffers and planes per buffer with the driver
809 * to be used during streaming;
810 * #) allocates internal buffer structures (&struct vb2_buffer), according to
811 * the agreed parameters;
812 * #) for MMAP memory type, allocates actual video memory, using the
813 * memory handling/allocation routines provided during queue initialization.
814 *
815 * If req->count is 0, all the memory will be freed instead.
816 *
817 * If the queue has been allocated previously by a previous vb2_core_reqbufs()
818 * call and the queue is not busy, memory will be reallocated.
819 *
820 * Return: returns zero on success; an error code otherwise.
821 */
822int vb2_core_reqbufs(struct vb2_queue *q, enum vb2_memory memory,
823 unsigned int flags, unsigned int *count);
824
825/**
826 * vb2_core_create_bufs() - Allocate buffers and any required auxiliary structs
827 * @q: pointer to &struct vb2_queue with videobuf2 queue.
828 * @memory: memory type, as defined by &enum vb2_memory.
829 * @flags: auxiliary queue/buffer management flags.
830 * @count: requested buffer count.
831 * @requested_planes: number of planes requested.
832 * @requested_sizes: array with the size of the planes.
833 * @first_index: index of the first created buffer, all allocated buffers have
834 * indices in the range [first_index..first_index+count-1]
835 *
836 * Videobuf2 core helper to implement VIDIOC_CREATE_BUFS() operation. It is
837 * called internally by VB2 by an API-specific handler, like
838 * ``videobuf2-v4l2.h``.
839 *
840 * This function:
841 *
842 * #) verifies parameter sanity;
843 * #) calls the &vb2_ops->queue_setup queue operation;
844 * #) performs any necessary memory allocations.
845 *
846 * Return: returns zero on success; an error code otherwise.
847 */
848int vb2_core_create_bufs(struct vb2_queue *q, enum vb2_memory memory,
849 unsigned int flags, unsigned int *count,
850 unsigned int requested_planes,
851 const unsigned int requested_sizes[],
852 unsigned int *first_index);
853
854/**
855 * vb2_core_prepare_buf() - Pass ownership of a buffer from userspace
856 * to the kernel.
857 * @q: pointer to &struct vb2_queue with videobuf2 queue.
858 * @vb: pointer to struct &vb2_buffer.
859 * @pb: buffer structure passed from userspace to
860 * &v4l2_ioctl_ops->vidioc_prepare_buf handler in driver.
861 *
862 * Videobuf2 core helper to implement VIDIOC_PREPARE_BUF() operation. It is
863 * called internally by VB2 by an API-specific handler, like
864 * ``videobuf2-v4l2.h``.
865 *
866 * The passed buffer should have been verified.
867 *
868 * This function calls vb2_ops->buf_prepare callback in the driver
869 * (if provided), in which driver-specific buffer initialization can
870 * be performed.
871 *
872 * Return: returns zero on success; an error code otherwise.
873 */
874int vb2_core_prepare_buf(struct vb2_queue *q, struct vb2_buffer *vb, void *pb);
875
876/**
877 * vb2_core_remove_bufs() -
878 * @q: pointer to &struct vb2_queue with videobuf2 queue.
879 * @start: first index of the range of buffers to remove.
880 * @count: number of buffers to remove.
881 *
882 * Return: returns zero on success; an error code otherwise.
883 */
884int vb2_core_remove_bufs(struct vb2_queue *q, unsigned int start, unsigned int count);
885
886/**
887 * vb2_core_qbuf() - Queue a buffer from userspace
888 *
889 * @q: pointer to &struct vb2_queue with videobuf2 queue.
890 * @vb: pointer to struct &vb2_buffer.
891 * @pb: buffer structure passed from userspace to
892 * v4l2_ioctl_ops->vidioc_qbuf handler in driver
893 * @req: pointer to &struct media_request, may be NULL.
894 *
895 * Videobuf2 core helper to implement VIDIOC_QBUF() operation. It is called
896 * internally by VB2 by an API-specific handler, like ``videobuf2-v4l2.h``.
897 *
898 * This function:
899 *
900 * #) If @req is non-NULL, then the buffer will be bound to this
901 * media request and it returns. The buffer will be prepared and
902 * queued to the driver (i.e. the next two steps) when the request
903 * itself is queued.
904 * #) if necessary, calls &vb2_ops->buf_prepare callback in the driver
905 * (if provided), in which driver-specific buffer initialization can
906 * be performed;
907 * #) if streaming is on, queues the buffer in driver by the means of
908 * &vb2_ops->buf_queue callback for processing.
909 *
910 * Return: returns zero on success; an error code otherwise.
911 */
912int vb2_core_qbuf(struct vb2_queue *q, struct vb2_buffer *vb, void *pb,
913 struct media_request *req);
914
915/**
916 * vb2_core_dqbuf() - Dequeue a buffer to the userspace
917 * @q: pointer to &struct vb2_queue with videobuf2 queue
918 * @pindex: pointer to the buffer index. May be NULL
919 * @pb: buffer structure passed from userspace to
920 * v4l2_ioctl_ops->vidioc_dqbuf handler in driver.
921 * @nonblocking: if true, this call will not sleep waiting for a buffer if no
922 * buffers ready for dequeuing are present. Normally the driver
923 * would be passing (file->f_flags & O_NONBLOCK) here.
924 *
925 * Videobuf2 core helper to implement VIDIOC_DQBUF() operation. It is called
926 * internally by VB2 by an API-specific handler, like ``videobuf2-v4l2.h``.
927 *
928 * This function:
929 *
930 * #) calls buf_finish callback in the driver (if provided), in which
931 * driver can perform any additional operations that may be required before
932 * returning the buffer to userspace, such as cache sync,
933 * #) the buffer struct members are filled with relevant information for
934 * the userspace.
935 *
936 * Return: returns zero on success; an error code otherwise.
937 */
938int vb2_core_dqbuf(struct vb2_queue *q, unsigned int *pindex, void *pb,
939 bool nonblocking);
940
941/**
942 * vb2_core_streamon() - Implements VB2 stream ON logic
943 *
944 * @q: pointer to &struct vb2_queue with videobuf2 queue
945 * @type: type of the queue to be started.
946 * For V4L2, this is defined by &enum v4l2_buf_type type.
947 *
948 * Videobuf2 core helper to implement VIDIOC_STREAMON() operation. It is called
949 * internally by VB2 by an API-specific handler, like ``videobuf2-v4l2.h``.
950 *
951 * Return: returns zero on success; an error code otherwise.
952 */
953int vb2_core_streamon(struct vb2_queue *q, unsigned int type);
954
955/**
956 * vb2_core_streamoff() - Implements VB2 stream OFF logic
957 *
958 * @q: pointer to &struct vb2_queue with videobuf2 queue
959 * @type: type of the queue to be started.
960 * For V4L2, this is defined by &enum v4l2_buf_type type.
961 *
962 * Videobuf2 core helper to implement VIDIOC_STREAMOFF() operation. It is
963 * called internally by VB2 by an API-specific handler, like
964 * ``videobuf2-v4l2.h``.
965 *
966 * Return: returns zero on success; an error code otherwise.
967 */
968int vb2_core_streamoff(struct vb2_queue *q, unsigned int type);
969
970/**
971 * vb2_core_expbuf() - Export a buffer as a file descriptor.
972 * @q: pointer to &struct vb2_queue with videobuf2 queue.
973 * @fd: pointer to the file descriptor associated with DMABUF
974 * (set by driver).
975 * @type: buffer type.
976 * @vb: pointer to struct &vb2_buffer.
977 * @plane: index of the plane to be exported, 0 for single plane queues
978 * @flags: file flags for newly created file, as defined at
979 * include/uapi/asm-generic/fcntl.h.
980 * Currently, the only used flag is %O_CLOEXEC.
981 * is supported, refer to manual of open syscall for more details.
982 *
983 *
984 * Videobuf2 core helper to implement VIDIOC_EXPBUF() operation. It is called
985 * internally by VB2 by an API-specific handler, like ``videobuf2-v4l2.h``.
986 *
987 * Return: returns zero on success; an error code otherwise.
988 */
989int vb2_core_expbuf(struct vb2_queue *q, int *fd, unsigned int type,
990 struct vb2_buffer *vb, unsigned int plane, unsigned int flags);
991
992/**
993 * vb2_core_queue_init() - initialize a videobuf2 queue
994 * @q: pointer to &struct vb2_queue with videobuf2 queue.
995 * This structure should be allocated in driver
996 *
997 * The &vb2_queue structure should be allocated by the driver. The driver is
998 * responsible of clearing it's content and setting initial values for some
999 * required entries before calling this function.
1000 *
1001 * .. note::
1002 *
1003 * The following fields at @q should be set before calling this function:
1004 * &vb2_queue->ops, &vb2_queue->mem_ops, &vb2_queue->type.
1005 */
1006int vb2_core_queue_init(struct vb2_queue *q);
1007
1008/**
1009 * vb2_core_queue_release() - stop streaming, release the queue and free memory
1010 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1011 *
1012 * This function stops streaming and performs necessary clean ups, including
1013 * freeing video buffer memory. The driver is responsible for freeing
1014 * the &struct vb2_queue itself.
1015 */
1016void vb2_core_queue_release(struct vb2_queue *q);
1017
1018/**
1019 * vb2_queue_error() - signal a fatal error on the queue
1020 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1021 *
1022 * Flag that a fatal unrecoverable error has occurred and wake up all processes
1023 * waiting on the queue. Polling will now set %EPOLLERR and queuing and dequeuing
1024 * buffers will return %-EIO.
1025 *
1026 * The error flag will be cleared when canceling the queue, either from
1027 * vb2_streamoff() or vb2_queue_release(). Drivers should thus not call this
1028 * function before starting the stream, otherwise the error flag will remain set
1029 * until the queue is released when closing the device node.
1030 */
1031void vb2_queue_error(struct vb2_queue *q);
1032
1033/**
1034 * vb2_mmap() - map video buffers into application address space.
1035 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1036 * @vma: pointer to &struct vm_area_struct with the vma passed
1037 * to the mmap file operation handler in the driver.
1038 *
1039 * Should be called from mmap file operation handler of a driver.
1040 * This function maps one plane of one of the available video buffers to
1041 * userspace. To map whole video memory allocated on reqbufs, this function
1042 * has to be called once per each plane per each buffer previously allocated.
1043 *
1044 * When the userspace application calls mmap, it passes to it an offset returned
1045 * to it earlier by the means of &v4l2_ioctl_ops->vidioc_querybuf handler.
1046 * That offset acts as a "cookie", which is then used to identify the plane
1047 * to be mapped.
1048 *
1049 * This function finds a plane with a matching offset and a mapping is performed
1050 * by the means of a provided memory operation.
1051 *
1052 * The return values from this function are intended to be directly returned
1053 * from the mmap handler in driver.
1054 */
1055int vb2_mmap(struct vb2_queue *q, struct vm_area_struct *vma);
1056
1057#ifndef CONFIG_MMU
1058/**
1059 * vb2_get_unmapped_area - map video buffers into application address space.
1060 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1061 * @addr: memory address.
1062 * @len: buffer size.
1063 * @pgoff: page offset.
1064 * @flags: memory flags.
1065 *
1066 * This function is used in noMMU platforms to propose address mapping
1067 * for a given buffer. It's intended to be used as a handler for the
1068 * &file_operations->get_unmapped_area operation.
1069 *
1070 * This is called by the mmap() syscall routines will call this
1071 * to get a proposed address for the mapping, when ``!CONFIG_MMU``.
1072 */
1073unsigned long vb2_get_unmapped_area(struct vb2_queue *q,
1074 unsigned long addr,
1075 unsigned long len,
1076 unsigned long pgoff,
1077 unsigned long flags);
1078#endif
1079
1080/**
1081 * vb2_core_poll() - implements poll syscall() logic.
1082 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1083 * @file: &struct file argument passed to the poll
1084 * file operation handler.
1085 * @wait: &poll_table wait argument passed to the poll
1086 * file operation handler.
1087 *
1088 * This function implements poll file operation handler for a driver.
1089 * For CAPTURE queues, if a buffer is ready to be dequeued, the userspace will
1090 * be informed that the file descriptor of a video device is available for
1091 * reading.
1092 * For OUTPUT queues, if a buffer is ready to be dequeued, the file descriptor
1093 * will be reported as available for writing.
1094 *
1095 * The return values from this function are intended to be directly returned
1096 * from poll handler in driver.
1097 */
1098__poll_t vb2_core_poll(struct vb2_queue *q, struct file *file,
1099 poll_table *wait);
1100
1101/**
1102 * vb2_read() - implements read() syscall logic.
1103 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1104 * @data: pointed to target userspace buffer
1105 * @count: number of bytes to read
1106 * @ppos: file handle position tracking pointer
1107 * @nonblock: mode selector (1 means blocking calls, 0 means nonblocking)
1108 */
1109size_t vb2_read(struct vb2_queue *q, char __user *data, size_t count,
1110 loff_t *ppos, int nonblock);
1111/**
1112 * vb2_write() - implements write() syscall logic.
1113 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1114 * @data: pointed to target userspace buffer
1115 * @count: number of bytes to write
1116 * @ppos: file handle position tracking pointer
1117 * @nonblock: mode selector (1 means blocking calls, 0 means nonblocking)
1118 */
1119size_t vb2_write(struct vb2_queue *q, const char __user *data, size_t count,
1120 loff_t *ppos, int nonblock);
1121
1122/**
1123 * typedef vb2_thread_fnc - callback function for use with vb2_thread.
1124 *
1125 * @vb: pointer to struct &vb2_buffer.
1126 * @priv: pointer to a private data.
1127 *
1128 * This is called whenever a buffer is dequeued in the thread.
1129 */
1130typedef int (*vb2_thread_fnc)(struct vb2_buffer *vb, void *priv);
1131
1132/**
1133 * vb2_thread_start() - start a thread for the given queue.
1134 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1135 * @fnc: &vb2_thread_fnc callback function.
1136 * @priv: priv pointer passed to the callback function.
1137 * @thread_name:the name of the thread. This will be prefixed with "vb2-".
1138 *
1139 * This starts a thread that will queue and dequeue until an error occurs
1140 * or vb2_thread_stop() is called.
1141 *
1142 * .. attention::
1143 *
1144 * This function should not be used for anything else but the videobuf2-dvb
1145 * support. If you think you have another good use-case for this, then please
1146 * contact the linux-media mailing list first.
1147 */
1148int vb2_thread_start(struct vb2_queue *q, vb2_thread_fnc fnc, void *priv,
1149 const char *thread_name);
1150
1151/**
1152 * vb2_thread_stop() - stop the thread for the given queue.
1153 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1154 */
1155int vb2_thread_stop(struct vb2_queue *q);
1156
1157/**
1158 * vb2_is_streaming() - return streaming status of the queue.
1159 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1160 */
1161static inline bool vb2_is_streaming(struct vb2_queue *q)
1162{
1163 return q->streaming;
1164}
1165
1166/**
1167 * vb2_fileio_is_active() - return true if fileio is active.
1168 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1169 *
1170 * This returns true if read() or write() is used to stream the data
1171 * as opposed to stream I/O. This is almost never an important distinction,
1172 * except in rare cases. One such case is that using read() or write() to
1173 * stream a format using %V4L2_FIELD_ALTERNATE is not allowed since there
1174 * is no way you can pass the field information of each buffer to/from
1175 * userspace. A driver that supports this field format should check for
1176 * this in the &vb2_ops->queue_setup op and reject it if this function returns
1177 * true.
1178 */
1179static inline bool vb2_fileio_is_active(struct vb2_queue *q)
1180{
1181 return q->fileio;
1182}
1183
1184/**
1185 * vb2_get_num_buffers() - get the number of buffer in a queue
1186 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1187 */
1188static inline unsigned int vb2_get_num_buffers(struct vb2_queue *q)
1189{
1190 if (q->bufs_bitmap)
1191 return bitmap_weight(src: q->bufs_bitmap, nbits: q->max_num_buffers);
1192
1193 return 0;
1194}
1195
1196/**
1197 * vb2_is_busy() - return busy status of the queue.
1198 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1199 *
1200 * This function checks if queue has any buffers allocated.
1201 */
1202static inline bool vb2_is_busy(struct vb2_queue *q)
1203{
1204 return !!q->is_busy;
1205}
1206
1207/**
1208 * vb2_get_drv_priv() - return driver private data associated with the queue.
1209 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1210 */
1211static inline void *vb2_get_drv_priv(struct vb2_queue *q)
1212{
1213 return q->drv_priv;
1214}
1215
1216/**
1217 * vb2_set_plane_payload() - set bytesused for the plane @plane_no.
1218 * @vb: pointer to &struct vb2_buffer to which the plane in
1219 * question belongs to.
1220 * @plane_no: plane number for which payload should be set.
1221 * @size: payload in bytes.
1222 */
1223static inline void vb2_set_plane_payload(struct vb2_buffer *vb,
1224 unsigned int plane_no, unsigned long size)
1225{
1226 /*
1227 * size must never be larger than the buffer length, so
1228 * warn and clamp to the buffer length if that's the case.
1229 */
1230 if (plane_no < vb->num_planes) {
1231 if (WARN_ON_ONCE(size > vb->planes[plane_no].length))
1232 size = vb->planes[plane_no].length;
1233 vb->planes[plane_no].bytesused = size;
1234 }
1235}
1236
1237/**
1238 * vb2_get_plane_payload() - get bytesused for the plane plane_no
1239 * @vb: pointer to &struct vb2_buffer to which the plane in
1240 * question belongs to.
1241 * @plane_no: plane number for which payload should be set.
1242 */
1243static inline unsigned long vb2_get_plane_payload(struct vb2_buffer *vb,
1244 unsigned int plane_no)
1245{
1246 if (plane_no < vb->num_planes)
1247 return vb->planes[plane_no].bytesused;
1248 return 0;
1249}
1250
1251/**
1252 * vb2_plane_size() - return plane size in bytes.
1253 * @vb: pointer to &struct vb2_buffer to which the plane in
1254 * question belongs to.
1255 * @plane_no: plane number for which size should be returned.
1256 */
1257static inline unsigned long
1258vb2_plane_size(struct vb2_buffer *vb, unsigned int plane_no)
1259{
1260 if (plane_no < vb->num_planes)
1261 return vb->planes[plane_no].length;
1262 return 0;
1263}
1264
1265/**
1266 * vb2_start_streaming_called() - return streaming status of driver.
1267 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1268 */
1269static inline bool vb2_start_streaming_called(struct vb2_queue *q)
1270{
1271 return q->start_streaming_called;
1272}
1273
1274/**
1275 * vb2_clear_last_buffer_dequeued() - clear last buffer dequeued flag of queue.
1276 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1277 */
1278static inline void vb2_clear_last_buffer_dequeued(struct vb2_queue *q)
1279{
1280 q->last_buffer_dequeued = false;
1281}
1282
1283/**
1284 * vb2_get_buffer() - get a buffer from a queue
1285 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1286 * @index: buffer index
1287 *
1288 * This function obtains a buffer from a queue, by its index.
1289 * Keep in mind that there is no refcounting involved in this
1290 * operation, so the buffer lifetime should be taken into
1291 * consideration.
1292 */
1293static inline struct vb2_buffer *vb2_get_buffer(struct vb2_queue *q,
1294 unsigned int index)
1295{
1296 if (!q->bufs)
1297 return NULL;
1298
1299 if (index >= q->max_num_buffers)
1300 return NULL;
1301
1302 if (test_bit(index, q->bufs_bitmap))
1303 return q->bufs[index];
1304 return NULL;
1305}
1306
1307/*
1308 * The following functions are not part of the vb2 core API, but are useful
1309 * functions for videobuf2-*.
1310 */
1311
1312/**
1313 * vb2_buffer_in_use() - return true if the buffer is in use and
1314 * the queue cannot be freed (by the means of VIDIOC_REQBUFS(0)) call.
1315 *
1316 * @vb: buffer for which plane size should be returned.
1317 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1318 */
1319bool vb2_buffer_in_use(struct vb2_queue *q, struct vb2_buffer *vb);
1320
1321/**
1322 * vb2_verify_memory_type() - Check whether the memory type and buffer type
1323 * passed to a buffer operation are compatible with the queue.
1324 *
1325 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1326 * @memory: memory model, as defined by enum &vb2_memory.
1327 * @type: private buffer type whose content is defined by the vb2-core
1328 * caller. For example, for V4L2, it should match
1329 * the types defined on enum &v4l2_buf_type.
1330 */
1331int vb2_verify_memory_type(struct vb2_queue *q,
1332 enum vb2_memory memory, unsigned int type);
1333
1334/**
1335 * vb2_request_object_is_buffer() - return true if the object is a buffer
1336 *
1337 * @obj: the request object.
1338 */
1339bool vb2_request_object_is_buffer(struct media_request_object *obj);
1340
1341/**
1342 * vb2_request_buffer_cnt() - return the number of buffers in the request
1343 *
1344 * @req: the request.
1345 */
1346unsigned int vb2_request_buffer_cnt(struct media_request *req);
1347
1348#endif /* _MEDIA_VIDEOBUF2_CORE_H */
1349

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