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 */
40 enum vb2_memory {
41 VB2_MEMORY_UNKNOWN = 0,
42 VB2_MEMORY_MMAP = 1,
43 VB2_MEMORY_USERPTR = 2,
44 VB2_MEMORY_DMABUF = 4,
45 };
46
47 struct vb2_fileio_data;
48 struct vb2_threadio_data;
49 struct 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 */
118 struct 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 */
178 struct 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 */
201 enum 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 */
223 enum 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
233 struct 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 */
249 struct 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 * planes: per-plane information; do not change
275 * queued_entry: entry on the queued buffers list, which holds
276 * all buffers queued from userspace
277 * done_entry: entry on the list that stores all buffers ready
278 * to be dequeued to userspace
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 * the buffers already allocated. If either \*num_planes
350 * or the requested 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_queued_buffers. 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 */
431 struct 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 */
472 struct 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 * @dev: device to use for the default allocation context if the driver
488 * doesn't fill in the @alloc_devs array.
489 * @dma_attrs: DMA attributes to use for the DMA.
490 * @bidirectional: when this flag is set the DMA direction for the buffers of
491 * this queue will be overridden with %DMA_BIDIRECTIONAL direction.
492 * This is useful in cases where the hardware (firmware) writes to
493 * a buffer which is mapped as read (%DMA_TO_DEVICE), or reads from
494 * buffer which is mapped for write (%DMA_FROM_DEVICE) in order
495 * to satisfy some internal hardware restrictions or adds a padding
496 * needed by the processing algorithm. In case the DMA mapping is
497 * not bidirectional but the hardware (firmware) trying to access
498 * the buffer (in the opposite direction) this could lead to an
499 * IOMMU protection faults.
500 * @fileio_read_once: report EOF after reading the first buffer
501 * @fileio_write_immediately: queue buffer after each write() call
502 * @allow_zero_bytesused: allow bytesused == 0 to be passed to the driver
503 * @quirk_poll_must_check_waiting_for_buffers: Return %EPOLLERR at poll when QBUF
504 * has not been called. This is a vb1 idiom that has been adopted
505 * also by vb2.
506 * @supports_requests: this queue supports the Request API.
507 * @requires_requests: this queue requires the Request API. If this is set to 1,
508 * then supports_requests must be set to 1 as well.
509 * @uses_qbuf: qbuf was used directly for this queue. Set to 1 the first
510 * time this is called. Set to 0 when the queue is canceled.
511 * If this is 1, then you cannot queue buffers from a request.
512 * @uses_requests: requests are used for this queue. Set to 1 the first time
513 * a request is queued. Set to 0 when the queue is canceled.
514 * If this is 1, then you cannot queue buffers directly.
515 * @allow_cache_hints: when set user-space can pass cache management hints in
516 * order to skip cache flush/invalidation on ->prepare() or/and
517 * ->finish().
518 * @non_coherent_mem: when set queue will attempt to allocate buffers using
519 * non-coherent memory.
520 * @lock: pointer to a mutex that protects the &struct vb2_queue. The
521 * driver can set this to a mutex to let the v4l2 core serialize
522 * the queuing ioctls. If the driver wants to handle locking
523 * itself, then this should be set to NULL. This lock is not used
524 * by the videobuf2 core API.
525 * @owner: The filehandle that 'owns' the buffers, i.e. the filehandle
526 * that called reqbufs, create_buffers or started fileio.
527 * This field is not used by the videobuf2 core API, but it allows
528 * drivers to easily associate an owner filehandle with the queue.
529 * @ops: driver-specific callbacks
530 * @mem_ops: memory allocator specific callbacks
531 * @buf_ops: callbacks to deliver buffer information.
532 * between user-space and kernel-space.
533 * @drv_priv: driver private data.
534 * @subsystem_flags: Flags specific to the subsystem (V4L2/DVB/etc.). Not used
535 * by the vb2 core.
536 * @buf_struct_size: size of the driver-specific buffer structure;
537 * "" indicates the driver doesn't want to use a custom buffer
538 * structure type. In that case a subsystem-specific struct
539 * will be used (in the case of V4L2 that is
540 * ``sizeof(struct vb2_v4l2_buffer)``). The first field of the
541 * driver-specific buffer structure must be the subsystem-specific
542 * struct (vb2_v4l2_buffer in the case of V4L2).
543 * @timestamp_flags: Timestamp flags; ``V4L2_BUF_FLAG_TIMESTAMP_*`` and
544 * ``V4L2_BUF_FLAG_TSTAMP_SRC_*``
545 * @gfp_flags: additional gfp flags used when allocating the buffers.
546 * Typically this is 0, but it may be e.g. %GFP_DMA or %__GFP_DMA32
547 * to force the buffer allocation to a specific memory zone.
548 * @min_queued_buffers: the minimum number of queued buffers needed before
549 * @start_streaming can be called. Used when a DMA engine
550 * cannot be started unless at least this number of buffers
551 * have been queued into the driver.
552 * VIDIOC_REQBUFS will ensure at least @min_queued_buffers + 1
553 * buffers will be allocated. Note that VIDIOC_CREATE_BUFS will not
554 * modify the requested buffer count.
555 * @min_reqbufs_allocation: the minimum number of buffers to be allocated when
556 * calling VIDIOC_REQBUFS. Note that VIDIOC_CREATE_BUFS will *not*
557 * modify the requested buffer count and does not use this field.
558 * Drivers can set this if there has to be a certain number of
559 * buffers available for the hardware to work effectively.
560 * This allows calling VIDIOC_REQBUFS with a buffer count of 1 and
561 * it will be automatically adjusted to a workable buffer count.
562 * If set, then @min_reqbufs_allocation must be larger than
563 * @min_queued_buffers + 1.
564 * If this field is > 3, then it is highly recommended that the
565 * driver implements the V4L2_CID_MIN_BUFFERS_FOR_CAPTURE/OUTPUT
566 * control.
567 * @alloc_devs: &struct device memory type/allocator-specific per-plane device
568 */
569 /*
570 * Private elements (won't appear at the uAPI book):
571 * @mmap_lock: private mutex used when buffers are allocated/freed/mmapped
572 * @memory: current memory type used
573 * @dma_dir: DMA mapping direction.
574 * @bufs: videobuf2 buffer structures. If it is non-NULL then
575 * bufs_bitmap is also non-NULL.
576 * @bufs_bitmap: bitmap tracking whether each bufs[] entry is used
577 * @max_num_buffers: upper limit of number of allocated/used buffers.
578 * If set to 0 v4l2 core will change it VB2_MAX_FRAME
579 * for backward compatibility.
580 * @queued_list: list of buffers currently queued from userspace
581 * @queued_count: number of buffers queued and ready for streaming.
582 * @owned_by_drv_count: number of buffers owned by the driver
583 * @done_list: list of buffers ready to be dequeued to userspace
584 * @done_lock: lock to protect done_list list
585 * @done_wq: waitqueue for processes waiting for buffers ready to be dequeued
586 * @streaming: current streaming state
587 * @start_streaming_called: @start_streaming was called successfully and we
588 * started streaming.
589 * @error: a fatal error occurred on the queue
590 * @waiting_for_buffers: used in poll() to check if vb2 is still waiting for
591 * buffers. Only set for capture queues if qbuf has not yet been
592 * called since poll() needs to return %EPOLLERR in that situation.
593 * @waiting_in_dqbuf: set by the core for the duration of a blocking DQBUF, when
594 * it has to wait for a buffer to become available with vb2_queue->lock
595 * released. Used to prevent destroying the queue by other threads.
596 * @is_multiplanar: set if buffer type is multiplanar
597 * @is_output: set if buffer type is output
598 * @is_busy: set if at least one buffer has been allocated at some time.
599 * @copy_timestamp: set if vb2-core should set timestamps
600 * @last_buffer_dequeued: used in poll() and DQBUF to immediately return if the
601 * last decoded buffer was already dequeued. Set for capture queues
602 * when a buffer with the %V4L2_BUF_FLAG_LAST is dequeued.
603 * @fileio: file io emulator internal data, used only if emulator is active
604 * @threadio: thread io internal data, used only if thread is active
605 * @name: queue name, used for logging purpose. Initialized automatically
606 * if left empty by drivers.
607 */
608 struct vb2_queue {
609 unsigned int type;
610 unsigned int io_modes;
611 struct device *dev;
612 unsigned long dma_attrs;
613 unsigned int bidirectional:1;
614 unsigned int fileio_read_once:1;
615 unsigned int fileio_write_immediately:1;
616 unsigned int allow_zero_bytesused:1;
617 unsigned int quirk_poll_must_check_waiting_for_buffers:1;
618 unsigned int supports_requests:1;
619 unsigned int requires_requests:1;
620 unsigned int uses_qbuf:1;
621 unsigned int uses_requests:1;
622 unsigned int allow_cache_hints:1;
623 unsigned int non_coherent_mem:1;
624
625 struct mutex *lock;
626 void *owner;
627
628 const struct vb2_ops *ops;
629 const struct vb2_mem_ops *mem_ops;
630 const struct vb2_buf_ops *buf_ops;
631
632 void *drv_priv;
633 u32 subsystem_flags;
634 unsigned int buf_struct_size;
635 u32 timestamp_flags;
636 gfp_t gfp_flags;
637 u32 min_queued_buffers;
638 u32 min_reqbufs_allocation;
639
640 struct device *alloc_devs[VB2_MAX_PLANES];
641
642 /* private: internal use only */
643 struct mutex mmap_lock;
644 unsigned int memory;
645 enum dma_data_direction dma_dir;
646 struct vb2_buffer **bufs;
647 unsigned long *bufs_bitmap;
648 unsigned int max_num_buffers;
649
650 struct list_head queued_list;
651 unsigned int queued_count;
652
653 atomic_t owned_by_drv_count;
654 struct list_head done_list;
655 spinlock_t done_lock;
656 wait_queue_head_t done_wq;
657
658 unsigned int streaming:1;
659 unsigned int start_streaming_called:1;
660 unsigned int error:1;
661 unsigned int waiting_for_buffers:1;
662 unsigned int waiting_in_dqbuf:1;
663 unsigned int is_multiplanar:1;
664 unsigned int is_output:1;
665 unsigned int is_busy:1;
666 unsigned int copy_timestamp:1;
667 unsigned int last_buffer_dequeued:1;
668
669 struct vb2_fileio_data *fileio;
670 struct vb2_threadio_data *threadio;
671
672 char name[32];
673
674 #ifdef CONFIG_VIDEO_ADV_DEBUG
675 /*
676 * Counters for how often these queue-related ops are
677 * called. Used to check for unbalanced ops.
678 */
679 u32 cnt_queue_setup;
680 u32 cnt_wait_prepare;
681 u32 cnt_wait_finish;
682 u32 cnt_prepare_streaming;
683 u32 cnt_start_streaming;
684 u32 cnt_stop_streaming;
685 u32 cnt_unprepare_streaming;
686 #endif
687 };
688
689 /**
690 * vb2_queue_allows_cache_hints() - Return true if the queue allows cache
691 * and memory consistency hints.
692 *
693 * @q: pointer to &struct vb2_queue with videobuf2 queue
694 */
695 static inline bool vb2_queue_allows_cache_hints(struct vb2_queue *q)
696 {
697 return q->allow_cache_hints && q->memory == VB2_MEMORY_MMAP;
698 }
699
700 /**
701 * vb2_plane_vaddr() - Return a kernel virtual address of a given plane.
702 * @vb: pointer to &struct vb2_buffer to which the plane in
703 * question belongs to.
704 * @plane_no: plane number for which the address is to be returned.
705 *
706 * This function returns a kernel virtual address of a given plane if
707 * such a mapping exist, NULL otherwise.
708 */
709 void *vb2_plane_vaddr(struct vb2_buffer *vb, unsigned int plane_no);
710
711 /**
712 * vb2_plane_cookie() - Return allocator specific cookie for the given plane.
713 * @vb: pointer to &struct vb2_buffer to which the plane in
714 * question belongs to.
715 * @plane_no: plane number for which the cookie is to be returned.
716 *
717 * This function returns an allocator specific cookie for a given plane if
718 * available, NULL otherwise. The allocator should provide some simple static
719 * inline function, which would convert this cookie to the allocator specific
720 * type that can be used directly by the driver to access the buffer. This can
721 * be for example physical address, pointer to scatter list or IOMMU mapping.
722 */
723 void *vb2_plane_cookie(struct vb2_buffer *vb, unsigned int plane_no);
724
725 /**
726 * vb2_buffer_done() - inform videobuf2 that an operation on a buffer
727 * is finished.
728 * @vb: pointer to &struct vb2_buffer to be used.
729 * @state: state of the buffer, as defined by &enum vb2_buffer_state.
730 * Either %VB2_BUF_STATE_DONE if the operation finished
731 * successfully, %VB2_BUF_STATE_ERROR if the operation finished
732 * with an error or %VB2_BUF_STATE_QUEUED.
733 *
734 * This function should be called by the driver after a hardware operation on
735 * a buffer is finished and the buffer may be returned to userspace. The driver
736 * cannot use this buffer anymore until it is queued back to it by videobuf
737 * by the means of &vb2_ops->buf_queue callback. Only buffers previously queued
738 * to the driver by &vb2_ops->buf_queue can be passed to this function.
739 *
740 * While streaming a buffer can only be returned in state DONE or ERROR.
741 * The &vb2_ops->start_streaming op can also return them in case the DMA engine
742 * cannot be started for some reason. In that case the buffers should be
743 * returned with state QUEUED to put them back into the queue.
744 */
745 void vb2_buffer_done(struct vb2_buffer *vb, enum vb2_buffer_state state);
746
747 /**
748 * vb2_discard_done() - discard all buffers marked as DONE.
749 * @q: pointer to &struct vb2_queue with videobuf2 queue.
750 *
751 * This function is intended to be used with suspend/resume operations. It
752 * discards all 'done' buffers as they would be too old to be requested after
753 * resume.
754 *
755 * Drivers must stop the hardware and synchronize with interrupt handlers and/or
756 * delayed works before calling this function to make sure no buffer will be
757 * touched by the driver and/or hardware.
758 */
759 void vb2_discard_done(struct vb2_queue *q);
760
761 /**
762 * vb2_wait_for_all_buffers() - wait until all buffers are given back to vb2.
763 * @q: pointer to &struct vb2_queue with videobuf2 queue.
764 *
765 * This function will wait until all buffers that have been given to the driver
766 * by &vb2_ops->buf_queue are given back to vb2 with vb2_buffer_done(). It
767 * doesn't call &vb2_ops->wait_prepare/&vb2_ops->wait_finish pair.
768 * It is intended to be called with all locks taken, for example from
769 * &vb2_ops->stop_streaming callback.
770 */
771 int vb2_wait_for_all_buffers(struct vb2_queue *q);
772
773 /**
774 * vb2_core_querybuf() - query video buffer information.
775 * @q: pointer to &struct vb2_queue with videobuf2 queue.
776 * @vb: pointer to struct &vb2_buffer.
777 * @pb: buffer struct passed from userspace.
778 *
779 * Videobuf2 core helper to implement VIDIOC_QUERYBUF() operation. It is called
780 * internally by VB2 by an API-specific handler, like ``videobuf2-v4l2.h``.
781 *
782 * The passed buffer should have been verified.
783 *
784 * This function fills the relevant information for the userspace.
785 *
786 * Return: returns zero on success; an error code otherwise.
787 */
788 void vb2_core_querybuf(struct vb2_queue *q, struct vb2_buffer *vb, void *pb);
789
790 /**
791 * vb2_core_reqbufs() - Initiate streaming.
792 * @q: pointer to &struct vb2_queue with videobuf2 queue.
793 * @memory: memory type, as defined by &enum vb2_memory.
794 * @flags: auxiliary queue/buffer management flags. Currently, the only
795 * used flag is %V4L2_MEMORY_FLAG_NON_COHERENT.
796 * @count: requested buffer count.
797 *
798 * Videobuf2 core helper to implement VIDIOC_REQBUF() operation. It is called
799 * internally by VB2 by an API-specific handler, like ``videobuf2-v4l2.h``.
800 *
801 * This function:
802 *
803 * #) verifies streaming parameters passed from the userspace;
804 * #) sets up the queue;
805 * #) negotiates number of buffers and planes per buffer with the driver
806 * to be used during streaming;
807 * #) allocates internal buffer structures (&struct vb2_buffer), according to
808 * the agreed parameters;
809 * #) for MMAP memory type, allocates actual video memory, using the
810 * memory handling/allocation routines provided during queue initialization.
811 *
812 * If req->count is 0, all the memory will be freed instead.
813 *
814 * If the queue has been allocated previously by a previous vb2_core_reqbufs()
815 * call and the queue is not busy, memory will be reallocated.
816 *
817 * Return: returns zero on success; an error code otherwise.
818 */
819 int vb2_core_reqbufs(struct vb2_queue *q, enum vb2_memory memory,
820 unsigned int flags, unsigned int *count);
821
822 /**
823 * vb2_core_create_bufs() - Allocate buffers and any required auxiliary structs
824 * @q: pointer to &struct vb2_queue with videobuf2 queue.
825 * @memory: memory type, as defined by &enum vb2_memory.
826 * @flags: auxiliary queue/buffer management flags.
827 * @count: requested buffer count.
828 * @requested_planes: number of planes requested.
829 * @requested_sizes: array with the size of the planes.
830 * @first_index: index of the first created buffer, all allocated buffers have
831 * indices in the range [first_index..first_index+count-1]
832 *
833 * Videobuf2 core helper to implement VIDIOC_CREATE_BUFS() operation. It is
834 * called internally by VB2 by an API-specific handler, like
835 * ``videobuf2-v4l2.h``.
836 *
837 * This function:
838 *
839 * #) verifies parameter sanity;
840 * #) calls the &vb2_ops->queue_setup queue operation;
841 * #) performs any necessary memory allocations.
842 *
843 * Return: returns zero on success; an error code otherwise.
844 */
845 int vb2_core_create_bufs(struct vb2_queue *q, enum vb2_memory memory,
846 unsigned int flags, unsigned int *count,
847 unsigned int requested_planes,
848 const unsigned int requested_sizes[],
849 unsigned int *first_index);
850
851 /**
852 * vb2_core_prepare_buf() - Pass ownership of a buffer from userspace
853 * to the kernel.
854 * @q: pointer to &struct vb2_queue with videobuf2 queue.
855 * @vb: pointer to struct &vb2_buffer.
856 * @pb: buffer structure passed from userspace to
857 * &v4l2_ioctl_ops->vidioc_prepare_buf handler in driver.
858 *
859 * Videobuf2 core helper to implement VIDIOC_PREPARE_BUF() operation. It is
860 * called internally by VB2 by an API-specific handler, like
861 * ``videobuf2-v4l2.h``.
862 *
863 * The passed buffer should have been verified.
864 *
865 * This function calls vb2_ops->buf_prepare callback in the driver
866 * (if provided), in which driver-specific buffer initialization can
867 * be performed.
868 *
869 * Return: returns zero on success; an error code otherwise.
870 */
871 int vb2_core_prepare_buf(struct vb2_queue *q, struct vb2_buffer *vb, void *pb);
872
873 /**
874 * vb2_core_remove_bufs() -
875 * @q: pointer to &struct vb2_queue with videobuf2 queue.
876 * @start: first index of the range of buffers to remove.
877 * @count: number of buffers to remove.
878 *
879 * Return: returns zero on success; an error code otherwise.
880 */
881 int vb2_core_remove_bufs(struct vb2_queue *q, unsigned int start, unsigned int count);
882
883 /**
884 * vb2_core_qbuf() - Queue a buffer from userspace
885 *
886 * @q: pointer to &struct vb2_queue with videobuf2 queue.
887 * @vb: pointer to struct &vb2_buffer.
888 * @pb: buffer structure passed from userspace to
889 * v4l2_ioctl_ops->vidioc_qbuf handler in driver
890 * @req: pointer to &struct media_request, may be NULL.
891 *
892 * Videobuf2 core helper to implement VIDIOC_QBUF() operation. It is called
893 * internally by VB2 by an API-specific handler, like ``videobuf2-v4l2.h``.
894 *
895 * This function:
896 *
897 * #) If @req is non-NULL, then the buffer will be bound to this
898 * media request and it returns. The buffer will be prepared and
899 * queued to the driver (i.e. the next two steps) when the request
900 * itself is queued.
901 * #) if necessary, calls &vb2_ops->buf_prepare callback in the driver
902 * (if provided), in which driver-specific buffer initialization can
903 * be performed;
904 * #) if streaming is on, queues the buffer in driver by the means of
905 * &vb2_ops->buf_queue callback for processing.
906 *
907 * Return: returns zero on success; an error code otherwise.
908 */
909 int vb2_core_qbuf(struct vb2_queue *q, struct vb2_buffer *vb, void *pb,
910 struct media_request *req);
911
912 /**
913 * vb2_core_dqbuf() - Dequeue a buffer to the userspace
914 * @q: pointer to &struct vb2_queue with videobuf2 queue
915 * @pindex: pointer to the buffer index. May be NULL
916 * @pb: buffer structure passed from userspace to
917 * v4l2_ioctl_ops->vidioc_dqbuf handler in driver.
918 * @nonblocking: if true, this call will not sleep waiting for a buffer if no
919 * buffers ready for dequeuing are present. Normally the driver
920 * would be passing (file->f_flags & O_NONBLOCK) here.
921 *
922 * Videobuf2 core helper to implement VIDIOC_DQBUF() operation. It is called
923 * internally by VB2 by an API-specific handler, like ``videobuf2-v4l2.h``.
924 *
925 * This function:
926 *
927 * #) calls buf_finish callback in the driver (if provided), in which
928 * driver can perform any additional operations that may be required before
929 * returning the buffer to userspace, such as cache sync,
930 * #) the buffer struct members are filled with relevant information for
931 * the userspace.
932 *
933 * Return: returns zero on success; an error code otherwise.
934 */
935 int vb2_core_dqbuf(struct vb2_queue *q, unsigned int *pindex, void *pb,
936 bool nonblocking);
937
938 /**
939 * vb2_core_streamon() - Implements VB2 stream ON logic
940 *
941 * @q: pointer to &struct vb2_queue with videobuf2 queue
942 * @type: type of the queue to be started.
943 * For V4L2, this is defined by &enum v4l2_buf_type type.
944 *
945 * Videobuf2 core helper to implement VIDIOC_STREAMON() operation. It is called
946 * internally by VB2 by an API-specific handler, like ``videobuf2-v4l2.h``.
947 *
948 * Return: returns zero on success; an error code otherwise.
949 */
950 int vb2_core_streamon(struct vb2_queue *q, unsigned int type);
951
952 /**
953 * vb2_core_streamoff() - Implements VB2 stream OFF logic
954 *
955 * @q: pointer to &struct vb2_queue with videobuf2 queue
956 * @type: type of the queue to be started.
957 * For V4L2, this is defined by &enum v4l2_buf_type type.
958 *
959 * Videobuf2 core helper to implement VIDIOC_STREAMOFF() operation. It is
960 * called internally by VB2 by an API-specific handler, like
961 * ``videobuf2-v4l2.h``.
962 *
963 * Return: returns zero on success; an error code otherwise.
964 */
965 int vb2_core_streamoff(struct vb2_queue *q, unsigned int type);
966
967 /**
968 * vb2_core_expbuf() - Export a buffer as a file descriptor.
969 * @q: pointer to &struct vb2_queue with videobuf2 queue.
970 * @fd: pointer to the file descriptor associated with DMABUF
971 * (set by driver).
972 * @type: buffer type.
973 * @vb: pointer to struct &vb2_buffer.
974 * @plane: index of the plane to be exported, 0 for single plane queues
975 * @flags: file flags for newly created file, as defined at
976 * include/uapi/asm-generic/fcntl.h.
977 * Currently, the only used flag is %O_CLOEXEC.
978 * is supported, refer to manual of open syscall for more details.
979 *
980 *
981 * Videobuf2 core helper to implement VIDIOC_EXPBUF() operation. It is called
982 * internally by VB2 by an API-specific handler, like ``videobuf2-v4l2.h``.
983 *
984 * Return: returns zero on success; an error code otherwise.
985 */
986 int vb2_core_expbuf(struct vb2_queue *q, int *fd, unsigned int type,
987 struct vb2_buffer *vb, unsigned int plane, unsigned int flags);
988
989 /**
990 * vb2_core_queue_init() - initialize a videobuf2 queue
991 * @q: pointer to &struct vb2_queue with videobuf2 queue.
992 * This structure should be allocated in driver
993 *
994 * The &vb2_queue structure should be allocated by the driver. The driver is
995 * responsible of clearing it's content and setting initial values for some
996 * required entries before calling this function.
997 *
998 * .. note::
999 *
1000 * The following fields at @q should be set before calling this function:
1001 * &vb2_queue->ops, &vb2_queue->mem_ops, &vb2_queue->type.
1002 */
1003 int vb2_core_queue_init(struct vb2_queue *q);
1004
1005 /**
1006 * vb2_core_queue_release() - stop streaming, release the queue and free memory
1007 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1008 *
1009 * This function stops streaming and performs necessary clean ups, including
1010 * freeing video buffer memory. The driver is responsible for freeing
1011 * the &struct vb2_queue itself.
1012 */
1013 void vb2_core_queue_release(struct vb2_queue *q);
1014
1015 /**
1016 * vb2_queue_error() - signal a fatal error on the queue
1017 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1018 *
1019 * Flag that a fatal unrecoverable error has occurred and wake up all processes
1020 * waiting on the queue. Polling will now set %EPOLLERR and queuing and dequeuing
1021 * buffers will return %-EIO.
1022 *
1023 * The error flag will be cleared when canceling the queue, either from
1024 * vb2_streamoff() or vb2_queue_release(). Drivers should thus not call this
1025 * function before starting the stream, otherwise the error flag will remain set
1026 * until the queue is released when closing the device node.
1027 */
1028 void vb2_queue_error(struct vb2_queue *q);
1029
1030 /**
1031 * vb2_mmap() - map video buffers into application address space.
1032 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1033 * @vma: pointer to &struct vm_area_struct with the vma passed
1034 * to the mmap file operation handler in the driver.
1035 *
1036 * Should be called from mmap file operation handler of a driver.
1037 * This function maps one plane of one of the available video buffers to
1038 * userspace. To map whole video memory allocated on reqbufs, this function
1039 * has to be called once per each plane per each buffer previously allocated.
1040 *
1041 * When the userspace application calls mmap, it passes to it an offset returned
1042 * to it earlier by the means of &v4l2_ioctl_ops->vidioc_querybuf handler.
1043 * That offset acts as a "cookie", which is then used to identify the plane
1044 * to be mapped.
1045 *
1046 * This function finds a plane with a matching offset and a mapping is performed
1047 * by the means of a provided memory operation.
1048 *
1049 * The return values from this function are intended to be directly returned
1050 * from the mmap handler in driver.
1051 */
1052 int vb2_mmap(struct vb2_queue *q, struct vm_area_struct *vma);
1053
1054 #ifndef CONFIG_MMU
1055 /**
1056 * vb2_get_unmapped_area - map video buffers into application address space.
1057 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1058 * @addr: memory address.
1059 * @len: buffer size.
1060 * @pgoff: page offset.
1061 * @flags: memory flags.
1062 *
1063 * This function is used in noMMU platforms to propose address mapping
1064 * for a given buffer. It's intended to be used as a handler for the
1065 * &file_operations->get_unmapped_area operation.
1066 *
1067 * This is called by the mmap() syscall routines will call this
1068 * to get a proposed address for the mapping, when ``!CONFIG_MMU``.
1069 */
1070 unsigned long vb2_get_unmapped_area(struct vb2_queue *q,
1071 unsigned long addr,
1072 unsigned long len,
1073 unsigned long pgoff,
1074 unsigned long flags);
1075 #endif
1076
1077 /**
1078 * vb2_core_poll() - implements poll syscall() logic.
1079 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1080 * @file: &struct file argument passed to the poll
1081 * file operation handler.
1082 * @wait: &poll_table wait argument passed to the poll
1083 * file operation handler.
1084 *
1085 * This function implements poll file operation handler for a driver.
1086 * For CAPTURE queues, if a buffer is ready to be dequeued, the userspace will
1087 * be informed that the file descriptor of a video device is available for
1088 * reading.
1089 * For OUTPUT queues, if a buffer is ready to be dequeued, the file descriptor
1090 * will be reported as available for writing.
1091 *
1092 * The return values from this function are intended to be directly returned
1093 * from poll handler in driver.
1094 */
1095 __poll_t vb2_core_poll(struct vb2_queue *q, struct file *file,
1096 poll_table *wait);
1097
1098 /**
1099 * vb2_read() - implements read() syscall logic.
1100 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1101 * @data: pointed to target userspace buffer
1102 * @count: number of bytes to read
1103 * @ppos: file handle position tracking pointer
1104 * @nonblock: mode selector (1 means blocking calls, 0 means nonblocking)
1105 */
1106 size_t vb2_read(struct vb2_queue *q, char __user *data, size_t count,
1107 loff_t *ppos, int nonblock);
1108 /**
1109 * vb2_write() - implements write() syscall logic.
1110 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1111 * @data: pointed to target userspace buffer
1112 * @count: number of bytes to write
1113 * @ppos: file handle position tracking pointer
1114 * @nonblock: mode selector (1 means blocking calls, 0 means nonblocking)
1115 */
1116 size_t vb2_write(struct vb2_queue *q, const char __user *data, size_t count,
1117 loff_t *ppos, int nonblock);
1118
1119 /**
1120 * typedef vb2_thread_fnc - callback function for use with vb2_thread.
1121 *
1122 * @vb: pointer to struct &vb2_buffer.
1123 * @priv: pointer to a private data.
1124 *
1125 * This is called whenever a buffer is dequeued in the thread.
1126 */
1127 typedef int (*vb2_thread_fnc)(struct vb2_buffer *vb, void *priv);
1128
1129 /**
1130 * vb2_thread_start() - start a thread for the given queue.
1131 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1132 * @fnc: &vb2_thread_fnc callback function.
1133 * @priv: priv pointer passed to the callback function.
1134 * @thread_name:the name of the thread. This will be prefixed with "vb2-".
1135 *
1136 * This starts a thread that will queue and dequeue until an error occurs
1137 * or vb2_thread_stop() is called.
1138 *
1139 * .. attention::
1140 *
1141 * This function should not be used for anything else but the videobuf2-dvb
1142 * support. If you think you have another good use-case for this, then please
1143 * contact the linux-media mailing list first.
1144 */
1145 int vb2_thread_start(struct vb2_queue *q, vb2_thread_fnc fnc, void *priv,
1146 const char *thread_name);
1147
1148 /**
1149 * vb2_thread_stop() - stop the thread for the given queue.
1150 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1151 */
1152 int vb2_thread_stop(struct vb2_queue *q);
1153
1154 /**
1155 * vb2_is_streaming() - return streaming status of the queue.
1156 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1157 */
1158 static inline bool vb2_is_streaming(struct vb2_queue *q)
1159 {
1160 return q->streaming;
1161 }
1162
1163 /**
1164 * vb2_fileio_is_active() - return true if fileio is active.
1165 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1166 *
1167 * This returns true if read() or write() is used to stream the data
1168 * as opposed to stream I/O. This is almost never an important distinction,
1169 * except in rare cases. One such case is that using read() or write() to
1170 * stream a format using %V4L2_FIELD_ALTERNATE is not allowed since there
1171 * is no way you can pass the field information of each buffer to/from
1172 * userspace. A driver that supports this field format should check for
1173 * this in the &vb2_ops->queue_setup op and reject it if this function returns
1174 * true.
1175 */
1176 static inline bool vb2_fileio_is_active(struct vb2_queue *q)
1177 {
1178 return q->fileio;
1179 }
1180
1181 /**
1182 * vb2_get_num_buffers() - get the number of buffer in a queue
1183 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1184 */
1185 static inline unsigned int vb2_get_num_buffers(struct vb2_queue *q)
1186 {
1187 if (q->bufs_bitmap)
1188 return bitmap_weight(q->bufs_bitmap, q->max_num_buffers);
1189
1190 return 0;
1191 }
1192
1193 /**
1194 * vb2_is_busy() - return busy status of the queue.
1195 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1196 *
1197 * This function checks if queue has any buffers allocated.
1198 */
1199 static inline bool vb2_is_busy(struct vb2_queue *q)
1200 {
1201 return !!q->is_busy;
1202 }
1203
1204 /**
1205 * vb2_get_drv_priv() - return driver private data associated with the queue.
1206 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1207 */
1208 static inline void *vb2_get_drv_priv(struct vb2_queue *q)
1209 {
1210 return q->drv_priv;
1211 }
1212
1213 /**
1214 * vb2_set_plane_payload() - set bytesused for the plane @plane_no.
1215 * @vb: pointer to &struct vb2_buffer to which the plane in
1216 * question belongs to.
1217 * @plane_no: plane number for which payload should be set.
1218 * @size: payload in bytes.
1219 */
1220 static inline void vb2_set_plane_payload(struct vb2_buffer *vb,
1221 unsigned int plane_no, unsigned long size)
1222 {
1223 /*
1224 * size must never be larger than the buffer length, so
1225 * warn and clamp to the buffer length if that's the case.
1226 */
1227 if (plane_no < vb->num_planes) {
1228 if (WARN_ON_ONCE(size > vb->planes[plane_no].length))
1229 size = vb->planes[plane_no].length;
1230 vb->planes[plane_no].bytesused = size;
1231 }
1232 }
1233
1234 /**
1235 * vb2_get_plane_payload() - get bytesused for the plane plane_no
1236 * @vb: pointer to &struct vb2_buffer to which the plane in
1237 * question belongs to.
1238 * @plane_no: plane number for which payload should be set.
1239 */
1240 static inline unsigned long vb2_get_plane_payload(struct vb2_buffer *vb,
1241 unsigned int plane_no)
1242 {
1243 if (plane_no < vb->num_planes)
1244 return vb->planes[plane_no].bytesused;
1245 return 0;
1246 }
1247
1248 /**
1249 * vb2_plane_size() - return plane size in bytes.
1250 * @vb: pointer to &struct vb2_buffer to which the plane in
1251 * question belongs to.
1252 * @plane_no: plane number for which size should be returned.
1253 */
1254 static inline unsigned long
1255 vb2_plane_size(struct vb2_buffer *vb, unsigned int plane_no)
1256 {
1257 if (plane_no < vb->num_planes)
1258 return vb->planes[plane_no].length;
1259 return 0;
1260 }
1261
1262 /**
1263 * vb2_start_streaming_called() - return streaming status of driver.
1264 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1265 */
1266 static inline bool vb2_start_streaming_called(struct vb2_queue *q)
1267 {
1268 return q->start_streaming_called;
1269 }
1270
1271 /**
1272 * vb2_clear_last_buffer_dequeued() - clear last buffer dequeued flag of queue.
1273 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1274 */
1275 static inline void vb2_clear_last_buffer_dequeued(struct vb2_queue *q)
1276 {
1277 q->last_buffer_dequeued = false;
1278 }
1279
1280 /**
1281 * vb2_get_buffer() - get a buffer from a queue
1282 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1283 * @index: buffer index
1284 *
1285 * This function obtains a buffer from a queue, by its index.
1286 * Keep in mind that there is no refcounting involved in this
1287 * operation, so the buffer lifetime should be taken into
1288 * consideration.
1289 */
1290 static inline struct vb2_buffer *vb2_get_buffer(struct vb2_queue *q,
1291 unsigned int index)
1292 {
1293 if (!q->bufs)
1294 return NULL;
1295
1296 if (index >= q->max_num_buffers)
1297 return NULL;
1298
1299 if (test_bit(index, q->bufs_bitmap))
1300 return q->bufs[index];
1301 return NULL;
1302 }
1303
1304 /*
1305 * The following functions are not part of the vb2 core API, but are useful
1306 * functions for videobuf2-*.
1307 */
1308
1309 /**
1310 * vb2_buffer_in_use() - return true if the buffer is in use and
1311 * the queue cannot be freed (by the means of VIDIOC_REQBUFS(0)) call.
1312 *
1313 * @vb: buffer for which plane size should be returned.
1314 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1315 */
1316 bool vb2_buffer_in_use(struct vb2_queue *q, struct vb2_buffer *vb);
1317
1318 /**
1319 * vb2_verify_memory_type() - Check whether the memory type and buffer type
1320 * passed to a buffer operation are compatible with the queue.
1321 *
1322 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1323 * @memory: memory model, as defined by enum &vb2_memory.
1324 * @type: private buffer type whose content is defined by the vb2-core
1325 * caller. For example, for V4L2, it should match
1326 * the types defined on enum &v4l2_buf_type.
1327 */
1328 int vb2_verify_memory_type(struct vb2_queue *q,
1329 enum vb2_memory memory, unsigned int type);
1330
1331 /**
1332 * vb2_request_object_is_buffer() - return true if the object is a buffer
1333 *
1334 * @obj: the request object.
1335 */
1336 bool vb2_request_object_is_buffer(struct media_request_object *obj);
1337
1338 /**
1339 * vb2_request_buffer_cnt() - return the number of buffers in the request
1340 *
1341 * @req: the request.
1342 */
1343 unsigned int vb2_request_buffer_cnt(struct media_request *req);
1344
1345 #endif /* _MEDIA_VIDEOBUF2_CORE_H */
1346
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