2 * videobuf2-core.h - Video Buffer 2 Core Framework
4 * Copyright (C) 2010 Samsung Electronics
6 * Author: Pawel Osciak <pawel@osciak.com>
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.
12 #ifndef _MEDIA_VIDEOBUF2_CORE_H
13 #define _MEDIA_VIDEOBUF2_CORE_H
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>
23 #define VB2_MAX_FRAME (32)
24 #define VB2_MAX_PLANES (8)
27 * enum vb2_memory - type of memory model used to make the buffers visible
30 * @VB2_MEMORY_UNKNOWN: Buffer status is unknown or it is not used yet on
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.
41 VB2_MEMORY_UNKNOWN = 0,
43 VB2_MEMORY_USERPTR = 2,
44 VB2_MEMORY_DMABUF = 4,
47 struct vb2_fileio_data;
48 struct vb2_threadio_data;
51 * struct vb2_mem_ops - memory handling/memory allocator operations.
52 * @alloc: allocate video memory and, optionally, allocator private data,
53 * return ERR_PTR() on failure or a pointer to allocator private,
54 * per-buffer data on success; the returned private structure
55 * will then be passed as @buf_priv argument to other ops in this
56 * structure. Additional gfp_flags to use when allocating the
57 * are also passed to this operation. These flags are from the
58 * gfp_flags field of vb2_queue. The size argument to this function
59 * shall be *page aligned*.
60 * @put: inform the allocator that the buffer will no longer be used;
61 * usually will result in the allocator freeing the buffer (if
62 * no other users of this buffer are present); the @buf_priv
63 * argument is the allocator private per-buffer structure
64 * previously returned from the alloc callback.
65 * @get_dmabuf: acquire userspace memory for a hardware operation; used for
66 * DMABUF memory types.
67 * @get_userptr: acquire userspace memory for a hardware operation; used for
68 * USERPTR memory types; vaddr is the address passed to the
69 * videobuf layer when queuing a video buffer of USERPTR type;
70 * should return an allocator private per-buffer structure
71 * associated with the buffer on success, ERR_PTR() on failure;
72 * the returned private structure will then be passed as @buf_priv
73 * argument to other ops in this structure.
74 * @put_userptr: inform the allocator that a USERPTR buffer will no longer
76 * @attach_dmabuf: attach a shared &struct dma_buf for a hardware operation;
77 * used for DMABUF memory types; dev is the alloc device
78 * dbuf is the shared dma_buf; returns ERR_PTR() on failure;
79 * allocator private per-buffer structure on success;
80 * this needs to be used for further accesses to the buffer.
81 * @detach_dmabuf: inform the exporter of the buffer that the current DMABUF
82 * buffer is no longer used; the @buf_priv argument is the
83 * allocator private per-buffer structure previously returned
84 * from the attach_dmabuf callback.
85 * @map_dmabuf: request for access to the dmabuf from allocator; the allocator
86 * of dmabuf is informed that this driver is going to use the
88 * @unmap_dmabuf: releases access control to the dmabuf - allocator is notified
89 * that this driver is done using the dmabuf for now.
90 * @prepare: called every time the buffer is passed from userspace to the
91 * driver, useful for cache synchronisation, optional.
92 * @finish: called every time the buffer is passed back from the driver
93 * to the userspace, also optional.
94 * @vaddr: return a kernel virtual address to a given memory buffer
95 * associated with the passed private structure or NULL if no
96 * such mapping exists.
97 * @cookie: return allocator specific cookie for a given memory buffer
98 * associated with the passed private structure or NULL if not
100 * @num_users: return the current number of users of a memory buffer;
101 * return 1 if the videobuf layer (or actually the driver using
102 * it) is the only user.
103 * @mmap: setup a userspace mapping for a given memory buffer under
104 * the provided virtual memory region.
106 * Those operations are used by the videobuf2 core to implement the memory
107 * handling/memory allocators for each type of supported streaming I/O method.
110 * #) Required ops for USERPTR types: get_userptr, put_userptr.
112 * #) Required ops for MMAP types: alloc, put, num_users, mmap.
114 * #) Required ops for read/write access types: alloc, put, num_users, vaddr.
116 * #) Required ops for DMABUF types: attach_dmabuf, detach_dmabuf,
117 * map_dmabuf, unmap_dmabuf.
120 void *(*alloc)(struct device *dev, unsigned long attrs,
122 enum dma_data_direction dma_dir,
124 void (*put)(void *buf_priv);
125 struct dma_buf *(*get_dmabuf)(void *buf_priv, unsigned long flags);
127 void *(*get_userptr)(struct device *dev, unsigned long vaddr,
129 enum dma_data_direction dma_dir);
130 void (*put_userptr)(void *buf_priv);
132 void (*prepare)(void *buf_priv);
133 void (*finish)(void *buf_priv);
135 void *(*attach_dmabuf)(struct device *dev,
136 struct dma_buf *dbuf,
138 enum dma_data_direction dma_dir);
139 void (*detach_dmabuf)(void *buf_priv);
140 int (*map_dmabuf)(void *buf_priv);
141 void (*unmap_dmabuf)(void *buf_priv);
143 void *(*vaddr)(void *buf_priv);
144 void *(*cookie)(void *buf_priv);
146 unsigned int (*num_users)(void *buf_priv);
148 int (*mmap)(void *buf_priv, struct vm_area_struct *vma);
152 * struct vb2_plane - plane information.
153 * @mem_priv: private data with this plane.
154 * @dbuf: dma_buf - shared buffer object.
155 * @dbuf_mapped: flag to show whether dbuf is mapped or not
156 * @bytesused: number of bytes occupied by data in the plane (payload).
157 * @length: size of this plane (NOT the payload) in bytes.
158 * @min_length: minimum required size of this plane (NOT the payload) in bytes.
159 * @length is always greater or equal to @min_length.
160 * @m: Union with memtype-specific data.
161 * @m.offset: when memory in the associated struct vb2_buffer is
162 * %VB2_MEMORY_MMAP, equals the offset from the start of
163 * the device memory for this plane (or is a "cookie" that
164 * should be passed to mmap() called on the video node).
165 * @m.userptr: when memory is %VB2_MEMORY_USERPTR, a userspace pointer
166 * pointing to this plane.
167 * @m.fd: when memory is %VB2_MEMORY_DMABUF, a userspace file
168 * descriptor associated with this plane.
169 * @data_offset: offset in the plane to the start of data; usually 0,
170 * unless there is a header in front of the data.
172 * Should contain enough information to be able to cover all the fields
173 * of &struct v4l2_plane at videodev2.h.
177 struct dma_buf *dbuf;
178 unsigned int dbuf_mapped;
179 unsigned int bytesused;
181 unsigned int min_length;
184 unsigned long userptr;
187 unsigned int data_offset;
191 * enum vb2_io_modes - queue access methods.
192 * @VB2_MMAP: driver supports MMAP with streaming API.
193 * @VB2_USERPTR: driver supports USERPTR with streaming API.
194 * @VB2_READ: driver supports read() style access.
195 * @VB2_WRITE: driver supports write() style access.
196 * @VB2_DMABUF: driver supports DMABUF with streaming API.
200 VB2_USERPTR = BIT(1),
207 * enum vb2_buffer_state - current video buffer state.
208 * @VB2_BUF_STATE_DEQUEUED: buffer under userspace control.
209 * @VB2_BUF_STATE_IN_REQUEST: buffer is queued in media request.
210 * @VB2_BUF_STATE_PREPARING: buffer is being prepared in videobuf.
211 * @VB2_BUF_STATE_QUEUED: buffer queued in videobuf, but not in driver.
212 * @VB2_BUF_STATE_ACTIVE: buffer queued in driver and possibly used
213 * in a hardware operation.
214 * @VB2_BUF_STATE_DONE: buffer returned from driver to videobuf, but
215 * not yet dequeued to userspace.
216 * @VB2_BUF_STATE_ERROR: same as above, but the operation on the buffer
217 * has ended with an error, which will be reported
218 * to the userspace when it is dequeued.
220 enum vb2_buffer_state {
221 VB2_BUF_STATE_DEQUEUED,
222 VB2_BUF_STATE_IN_REQUEST,
223 VB2_BUF_STATE_PREPARING,
224 VB2_BUF_STATE_QUEUED,
225 VB2_BUF_STATE_ACTIVE,
233 * struct vb2_buffer - represents a video buffer.
234 * @vb2_queue: pointer to &struct vb2_queue with the queue to
235 * which this driver belongs.
236 * @index: id number of the buffer.
237 * @type: buffer type.
238 * @memory: the method, in which the actual data is passed.
239 * @num_planes: number of planes in the buffer
240 * on an internal driver queue.
241 * @timestamp: frame timestamp in ns.
242 * @request: the request this buffer is associated with.
243 * @req_obj: used to bind this buffer to a request. This
244 * request object has a refcount.
247 struct vb2_queue *vb2_queue;
251 unsigned int num_planes;
253 struct media_request *request;
254 struct media_request_object req_obj;
256 /* private: internal use only
258 * state: current buffer state; do not change
259 * synced: this buffer has been synced for DMA, i.e. the
260 * 'prepare' memop was called. It is cleared again
261 * after the 'finish' memop is called.
262 * prepared: this buffer has been prepared, i.e. the
263 * buf_prepare op was called. It is cleared again
264 * after the 'buf_finish' op is called.
265 * copied_timestamp: the timestamp of this capture buffer was copied
266 * from an output buffer.
267 * need_cache_sync_on_prepare: when set buffer's ->prepare() function
268 * performs cache sync/invalidation.
269 * need_cache_sync_on_finish: when set buffer's ->finish() function
270 * performs cache sync/invalidation.
271 * queued_entry: entry on the queued buffers list, which holds
272 * all buffers queued from userspace
273 * done_entry: entry on the list that stores all buffers ready
274 * to be dequeued to userspace
275 * vb2_plane: per-plane information; do not change
277 enum vb2_buffer_state state;
278 unsigned int synced:1;
279 unsigned int prepared:1;
280 unsigned int copied_timestamp:1;
281 unsigned int need_cache_sync_on_prepare:1;
282 unsigned int need_cache_sync_on_finish:1;
284 struct vb2_plane planes[VB2_MAX_PLANES];
285 struct list_head queued_entry;
286 struct list_head done_entry;
287 #ifdef CONFIG_VIDEO_ADV_DEBUG
289 * Counters for how often these buffer-related ops are
290 * called. Used to check for unbalanced ops.
294 u32 cnt_mem_get_dmabuf;
295 u32 cnt_mem_get_userptr;
296 u32 cnt_mem_put_userptr;
299 u32 cnt_mem_attach_dmabuf;
300 u32 cnt_mem_detach_dmabuf;
301 u32 cnt_mem_map_dmabuf;
302 u32 cnt_mem_unmap_dmabuf;
305 u32 cnt_mem_num_users;
308 u32 cnt_buf_out_validate;
314 u32 cnt_buf_request_complete;
316 /* This counts the number of calls to vb2_buffer_done() */
322 * struct vb2_ops - driver-specific callbacks.
324 * These operations are not called from interrupt context except where
325 * mentioned specifically.
327 * @queue_setup: called from VIDIOC_REQBUFS() and VIDIOC_CREATE_BUFS()
328 * handlers before memory allocation. It can be called
329 * twice: if the original number of requested buffers
330 * could not be allocated, then it will be called a
331 * second time with the actually allocated number of
332 * buffers to verify if that is OK.
333 * The driver should return the required number of buffers
334 * in \*num_buffers, the required number of planes per
335 * buffer in \*num_planes, the size of each plane should be
336 * set in the sizes\[\] array and optional per-plane
337 * allocator specific device in the alloc_devs\[\] array.
338 * When called from VIDIOC_REQBUFS(), \*num_planes == 0,
339 * the driver has to use the currently configured format to
340 * determine the plane sizes and \*num_buffers is the total
341 * number of buffers that are being allocated. When called
342 * from VIDIOC_CREATE_BUFS(), \*num_planes != 0 and it
343 * describes the requested number of planes and sizes\[\]
344 * contains the requested plane sizes. In this case
345 * \*num_buffers are being allocated additionally to
346 * q->num_buffers. If either \*num_planes or the requested
347 * sizes are invalid callback must return %-EINVAL.
348 * @wait_prepare: release any locks taken while calling vb2 functions;
349 * it is called before an ioctl needs to wait for a new
350 * buffer to arrive; required to avoid a deadlock in
351 * blocking access type.
352 * @wait_finish: reacquire all locks released in the previous callback;
353 * required to continue operation after sleeping while
354 * waiting for a new buffer to arrive.
355 * @buf_out_validate: called when the output buffer is prepared or queued
356 * to a request; drivers can use this to validate
357 * userspace-provided information; this is required only
359 * @buf_init: called once after allocating a buffer (in MMAP case)
360 * or after acquiring a new USERPTR buffer; drivers may
361 * perform additional buffer-related initialization;
362 * initialization failure (return != 0) will prevent
363 * queue setup from completing successfully; optional.
364 * @buf_prepare: called every time the buffer is queued from userspace
365 * and from the VIDIOC_PREPARE_BUF() ioctl; drivers may
366 * perform any initialization required before each
367 * hardware operation in this callback; drivers can
368 * access/modify the buffer here as it is still synced for
369 * the CPU; drivers that support VIDIOC_CREATE_BUFS() must
370 * also validate the buffer size; if an error is returned,
371 * the buffer will not be queued in driver; optional.
372 * @buf_finish: called before every dequeue of the buffer back to
373 * userspace; the buffer is synced for the CPU, so drivers
374 * can access/modify the buffer contents; drivers may
375 * perform any operations required before userspace
376 * accesses the buffer; optional. The buffer state can be
377 * one of the following: %DONE and %ERROR occur while
378 * streaming is in progress, and the %PREPARED state occurs
379 * when the queue has been canceled and all pending
380 * buffers are being returned to their default %DEQUEUED
381 * state. Typically you only have to do something if the
382 * state is %VB2_BUF_STATE_DONE, since in all other cases
383 * the buffer contents will be ignored anyway.
384 * @buf_cleanup: called once before the buffer is freed; drivers may
385 * perform any additional cleanup; optional.
386 * @start_streaming: called once to enter 'streaming' state; the driver may
387 * receive buffers with @buf_queue callback
388 * before @start_streaming is called; the driver gets the
389 * number of already queued buffers in count parameter;
390 * driver can return an error if hardware fails, in that
391 * case all buffers that have been already given by
392 * the @buf_queue callback are to be returned by the driver
393 * by calling vb2_buffer_done() with %VB2_BUF_STATE_QUEUED.
394 * If you need a minimum number of buffers before you can
395 * start streaming, then set
396 * &vb2_queue->min_buffers_needed. If that is non-zero
397 * then @start_streaming won't be called until at least
398 * that many buffers have been queued up by userspace.
399 * @stop_streaming: called when 'streaming' state must be disabled; driver
400 * should stop any DMA transactions or wait until they
401 * finish and give back all buffers it got from &buf_queue
402 * callback by calling vb2_buffer_done() with either
403 * %VB2_BUF_STATE_DONE or %VB2_BUF_STATE_ERROR; may use
404 * vb2_wait_for_all_buffers() function
405 * @buf_queue: passes buffer vb to the driver; driver may start
406 * hardware operation on this buffer; driver should give
407 * the buffer back by calling vb2_buffer_done() function;
408 * it is always called after calling VIDIOC_STREAMON()
409 * ioctl; might be called before @start_streaming callback
410 * if user pre-queued buffers before calling
412 * @buf_request_complete: a buffer that was never queued to the driver but is
413 * associated with a queued request was canceled.
414 * The driver will have to mark associated objects in the
415 * request as completed; required if requests are
419 int (*queue_setup)(struct vb2_queue *q,
420 unsigned int *num_buffers, unsigned int *num_planes,
421 unsigned int sizes[], struct device *alloc_devs[]);
423 void (*wait_prepare)(struct vb2_queue *q);
424 void (*wait_finish)(struct vb2_queue *q);
426 int (*buf_out_validate)(struct vb2_buffer *vb);
427 int (*buf_init)(struct vb2_buffer *vb);
428 int (*buf_prepare)(struct vb2_buffer *vb);
429 void (*buf_finish)(struct vb2_buffer *vb);
430 void (*buf_cleanup)(struct vb2_buffer *vb);
432 int (*start_streaming)(struct vb2_queue *q, unsigned int count);
433 void (*stop_streaming)(struct vb2_queue *q);
435 void (*buf_queue)(struct vb2_buffer *vb);
437 void (*buf_request_complete)(struct vb2_buffer *vb);
441 * struct vb2_buf_ops - driver-specific callbacks.
443 * @verify_planes_array: Verify that a given user space structure contains
444 * enough planes for the buffer. This is called
445 * for each dequeued buffer.
446 * @init_buffer: given a &vb2_buffer initialize the extra data after
448 * For V4L2 this is a &struct vb2_v4l2_buffer.
449 * @fill_user_buffer: given a &vb2_buffer fill in the userspace structure.
450 * For V4L2 this is a &struct v4l2_buffer.
451 * @fill_vb2_buffer: given a userspace structure, fill in the &vb2_buffer.
452 * If the userspace structure is invalid, then this op
453 * will return an error.
454 * @copy_timestamp: copy the timestamp from a userspace structure to
455 * the &struct vb2_buffer.
458 int (*verify_planes_array)(struct vb2_buffer *vb, const void *pb);
459 void (*init_buffer)(struct vb2_buffer *vb);
460 void (*fill_user_buffer)(struct vb2_buffer *vb, void *pb);
461 int (*fill_vb2_buffer)(struct vb2_buffer *vb, struct vb2_plane *planes);
462 void (*copy_timestamp)(struct vb2_buffer *vb, const void *pb);
466 * struct vb2_queue - a videobuf queue.
468 * @type: private buffer type whose content is defined by the vb2-core
469 * caller. For example, for V4L2, it should match
470 * the types defined on &enum v4l2_buf_type.
471 * @io_modes: supported io methods (see &enum vb2_io_modes).
472 * @alloc_devs: &struct device memory type/allocator-specific per-plane device
473 * @dev: device to use for the default allocation context if the driver
474 * doesn't fill in the @alloc_devs array.
475 * @dma_attrs: DMA attributes to use for the DMA.
476 * @bidirectional: when this flag is set the DMA direction for the buffers of
477 * this queue will be overridden with %DMA_BIDIRECTIONAL direction.
478 * This is useful in cases where the hardware (firmware) writes to
479 * a buffer which is mapped as read (%DMA_TO_DEVICE), or reads from
480 * buffer which is mapped for write (%DMA_FROM_DEVICE) in order
481 * to satisfy some internal hardware restrictions or adds a padding
482 * needed by the processing algorithm. In case the DMA mapping is
483 * not bidirectional but the hardware (firmware) trying to access
484 * the buffer (in the opposite direction) this could lead to an
485 * IOMMU protection faults.
486 * @fileio_read_once: report EOF after reading the first buffer
487 * @fileio_write_immediately: queue buffer after each write() call
488 * @allow_zero_bytesused: allow bytesused == 0 to be passed to the driver
489 * @quirk_poll_must_check_waiting_for_buffers: Return %EPOLLERR at poll when QBUF
490 * has not been called. This is a vb1 idiom that has been adopted
492 * @supports_requests: this queue supports the Request API.
493 * @requires_requests: this queue requires the Request API. If this is set to 1,
494 * then supports_requests must be set to 1 as well.
495 * @uses_qbuf: qbuf was used directly for this queue. Set to 1 the first
496 * time this is called. Set to 0 when the queue is canceled.
497 * If this is 1, then you cannot queue buffers from a request.
498 * @uses_requests: requests are used for this queue. Set to 1 the first time
499 * a request is queued. Set to 0 when the queue is canceled.
500 * If this is 1, then you cannot queue buffers directly.
501 * @allow_cache_hints: when set user-space can pass cache management hints in
502 * order to skip cache flush/invalidation on ->prepare() or/and
504 * @lock: pointer to a mutex that protects the &struct vb2_queue. The
505 * driver can set this to a mutex to let the v4l2 core serialize
506 * the queuing ioctls. If the driver wants to handle locking
507 * itself, then this should be set to NULL. This lock is not used
508 * by the videobuf2 core API.
509 * @owner: The filehandle that 'owns' the buffers, i.e. the filehandle
510 * that called reqbufs, create_buffers or started fileio.
511 * This field is not used by the videobuf2 core API, but it allows
512 * drivers to easily associate an owner filehandle with the queue.
513 * @ops: driver-specific callbacks
514 * @mem_ops: memory allocator specific callbacks
515 * @buf_ops: callbacks to deliver buffer information.
516 * between user-space and kernel-space.
517 * @drv_priv: driver private data.
518 * @subsystem_flags: Flags specific to the subsystem (V4L2/DVB/etc.). Not used
520 * @buf_struct_size: size of the driver-specific buffer structure;
521 * "0" indicates the driver doesn't want to use a custom buffer
522 * structure type. In that case a subsystem-specific struct
523 * will be used (in the case of V4L2 that is
524 * ``sizeof(struct vb2_v4l2_buffer)``). The first field of the
525 * driver-specific buffer structure must be the subsystem-specific
526 * struct (vb2_v4l2_buffer in the case of V4L2).
527 * @timestamp_flags: Timestamp flags; ``V4L2_BUF_FLAG_TIMESTAMP_*`` and
528 * ``V4L2_BUF_FLAG_TSTAMP_SRC_*``
529 * @gfp_flags: additional gfp flags used when allocating the buffers.
530 * Typically this is 0, but it may be e.g. %GFP_DMA or %__GFP_DMA32
531 * to force the buffer allocation to a specific memory zone.
532 * @min_buffers_needed: the minimum number of buffers needed before
533 * @start_streaming can be called. Used when a DMA engine
534 * cannot be started unless at least this number of buffers
535 * have been queued into the driver.
538 * Private elements (won't appear at the uAPI book):
539 * @mmap_lock: private mutex used when buffers are allocated/freed/mmapped
540 * @memory: current memory type used
541 * @dma_dir: DMA mapping direction.
542 * @bufs: videobuf buffer structures
543 * @num_buffers: number of allocated/used buffers
544 * @queued_list: list of buffers currently queued from userspace
545 * @queued_count: number of buffers queued and ready for streaming.
546 * @owned_by_drv_count: number of buffers owned by the driver
547 * @done_list: list of buffers ready to be dequeued to userspace
548 * @done_lock: lock to protect done_list list
549 * @done_wq: waitqueue for processes waiting for buffers ready to be dequeued
550 * @streaming: current streaming state
551 * @start_streaming_called: @start_streaming was called successfully and we
553 * @error: a fatal error occurred on the queue
554 * @waiting_for_buffers: used in poll() to check if vb2 is still waiting for
555 * buffers. Only set for capture queues if qbuf has not yet been
556 * called since poll() needs to return %EPOLLERR in that situation.
557 * @is_multiplanar: set if buffer type is multiplanar
558 * @is_output: set if buffer type is output
559 * @copy_timestamp: set if vb2-core should set timestamps
560 * @last_buffer_dequeued: used in poll() and DQBUF to immediately return if the
561 * last decoded buffer was already dequeued. Set for capture queues
562 * when a buffer with the %V4L2_BUF_FLAG_LAST is dequeued.
563 * @fileio: file io emulator internal data, used only if emulator is active
564 * @threadio: thread io internal data, used only if thread is active
565 * @name: queue name, used for logging purpose. Initialized automatically
566 * if left empty by drivers.
570 unsigned int io_modes;
572 unsigned long dma_attrs;
573 unsigned int bidirectional:1;
574 unsigned int fileio_read_once:1;
575 unsigned int fileio_write_immediately:1;
576 unsigned int allow_zero_bytesused:1;
577 unsigned int quirk_poll_must_check_waiting_for_buffers:1;
578 unsigned int supports_requests:1;
579 unsigned int requires_requests:1;
580 unsigned int uses_qbuf:1;
581 unsigned int uses_requests:1;
582 unsigned int allow_cache_hints:1;
587 const struct vb2_ops *ops;
588 const struct vb2_mem_ops *mem_ops;
589 const struct vb2_buf_ops *buf_ops;
593 unsigned int buf_struct_size;
596 u32 min_buffers_needed;
598 struct device *alloc_devs[VB2_MAX_PLANES];
600 /* private: internal use only */
601 struct mutex mmap_lock;
603 enum dma_data_direction dma_dir;
604 struct vb2_buffer *bufs[VB2_MAX_FRAME];
605 unsigned int num_buffers;
607 struct list_head queued_list;
608 unsigned int queued_count;
610 atomic_t owned_by_drv_count;
611 struct list_head done_list;
612 spinlock_t done_lock;
613 wait_queue_head_t done_wq;
615 unsigned int streaming:1;
616 unsigned int start_streaming_called:1;
617 unsigned int error:1;
618 unsigned int waiting_for_buffers:1;
619 unsigned int waiting_in_dqbuf:1;
620 unsigned int is_multiplanar:1;
621 unsigned int is_output:1;
622 unsigned int copy_timestamp:1;
623 unsigned int last_buffer_dequeued:1;
625 struct vb2_fileio_data *fileio;
626 struct vb2_threadio_data *threadio;
630 #ifdef CONFIG_VIDEO_ADV_DEBUG
632 * Counters for how often these queue-related ops are
633 * called. Used to check for unbalanced ops.
636 u32 cnt_wait_prepare;
638 u32 cnt_start_streaming;
639 u32 cnt_stop_streaming;
644 * vb2_queue_allows_cache_hints() - Return true if the queue allows cache
645 * and memory consistency hints.
647 * @q: pointer to &struct vb2_queue with videobuf2 queue
649 static inline bool vb2_queue_allows_cache_hints(struct vb2_queue *q)
651 return q->allow_cache_hints && q->memory == VB2_MEMORY_MMAP;
655 * vb2_plane_vaddr() - Return a kernel virtual address of a given plane.
656 * @vb: pointer to &struct vb2_buffer to which the plane in
657 * question belongs to.
658 * @plane_no: plane number for which the address is to be returned.
660 * This function returns a kernel virtual address of a given plane if
661 * such a mapping exist, NULL otherwise.
663 void *vb2_plane_vaddr(struct vb2_buffer *vb, unsigned int plane_no);
666 * vb2_plane_cookie() - Return allocator specific cookie for the given plane.
667 * @vb: pointer to &struct vb2_buffer to which the plane in
668 * question belongs to.
669 * @plane_no: plane number for which the cookie is to be returned.
671 * This function returns an allocator specific cookie for a given plane if
672 * available, NULL otherwise. The allocator should provide some simple static
673 * inline function, which would convert this cookie to the allocator specific
674 * type that can be used directly by the driver to access the buffer. This can
675 * be for example physical address, pointer to scatter list or IOMMU mapping.
677 void *vb2_plane_cookie(struct vb2_buffer *vb, unsigned int plane_no);
680 * vb2_buffer_done() - inform videobuf that an operation on a buffer
682 * @vb: pointer to &struct vb2_buffer to be used.
683 * @state: state of the buffer, as defined by &enum vb2_buffer_state.
684 * Either %VB2_BUF_STATE_DONE if the operation finished
685 * successfully, %VB2_BUF_STATE_ERROR if the operation finished
686 * with an error or %VB2_BUF_STATE_QUEUED.
688 * This function should be called by the driver after a hardware operation on
689 * a buffer is finished and the buffer may be returned to userspace. The driver
690 * cannot use this buffer anymore until it is queued back to it by videobuf
691 * by the means of &vb2_ops->buf_queue callback. Only buffers previously queued
692 * to the driver by &vb2_ops->buf_queue can be passed to this function.
694 * While streaming a buffer can only be returned in state DONE or ERROR.
695 * The &vb2_ops->start_streaming op can also return them in case the DMA engine
696 * cannot be started for some reason. In that case the buffers should be
697 * returned with state QUEUED to put them back into the queue.
699 void vb2_buffer_done(struct vb2_buffer *vb, enum vb2_buffer_state state);
702 * vb2_discard_done() - discard all buffers marked as DONE.
703 * @q: pointer to &struct vb2_queue with videobuf2 queue.
705 * This function is intended to be used with suspend/resume operations. It
706 * discards all 'done' buffers as they would be too old to be requested after
709 * Drivers must stop the hardware and synchronize with interrupt handlers and/or
710 * delayed works before calling this function to make sure no buffer will be
711 * touched by the driver and/or hardware.
713 void vb2_discard_done(struct vb2_queue *q);
716 * vb2_wait_for_all_buffers() - wait until all buffers are given back to vb2.
717 * @q: pointer to &struct vb2_queue with videobuf2 queue.
719 * This function will wait until all buffers that have been given to the driver
720 * by &vb2_ops->buf_queue are given back to vb2 with vb2_buffer_done(). It
721 * doesn't call &vb2_ops->wait_prepare/&vb2_ops->wait_finish pair.
722 * It is intended to be called with all locks taken, for example from
723 * &vb2_ops->stop_streaming callback.
725 int vb2_wait_for_all_buffers(struct vb2_queue *q);
728 * vb2_core_querybuf() - query video buffer information.
729 * @q: pointer to &struct vb2_queue with videobuf2 queue.
730 * @index: id number of the buffer.
731 * @pb: buffer struct passed from userspace.
733 * Videobuf2 core helper to implement VIDIOC_QUERYBUF() operation. It is called
734 * internally by VB2 by an API-specific handler, like ``videobuf2-v4l2.h``.
736 * The passed buffer should have been verified.
738 * This function fills the relevant information for the userspace.
740 * Return: returns zero on success; an error code otherwise.
742 void vb2_core_querybuf(struct vb2_queue *q, unsigned int index, void *pb);
745 * vb2_core_reqbufs() - Initiate streaming.
746 * @q: pointer to &struct vb2_queue with videobuf2 queue.
747 * @memory: memory type, as defined by &enum vb2_memory.
748 * @count: requested buffer count.
750 * Videobuf2 core helper to implement VIDIOC_REQBUF() operation. It is called
751 * internally by VB2 by an API-specific handler, like ``videobuf2-v4l2.h``.
755 * #) verifies streaming parameters passed from the userspace;
756 * #) sets up the queue;
757 * #) negotiates number of buffers and planes per buffer with the driver
758 * to be used during streaming;
759 * #) allocates internal buffer structures (&struct vb2_buffer), according to
760 * the agreed parameters;
761 * #) for MMAP memory type, allocates actual video memory, using the
762 * memory handling/allocation routines provided during queue initialization.
764 * If req->count is 0, all the memory will be freed instead.
766 * If the queue has been allocated previously by a previous vb2_core_reqbufs()
767 * call and the queue is not busy, memory will be reallocated.
769 * Return: returns zero on success; an error code otherwise.
771 int vb2_core_reqbufs(struct vb2_queue *q, enum vb2_memory memory,
772 unsigned int *count);
775 * vb2_core_create_bufs() - Allocate buffers and any required auxiliary structs
776 * @q: pointer to &struct vb2_queue with videobuf2 queue.
777 * @memory: memory type, as defined by &enum vb2_memory.
778 * @count: requested buffer count.
779 * @requested_planes: number of planes requested.
780 * @requested_sizes: array with the size of the planes.
782 * Videobuf2 core helper to implement VIDIOC_CREATE_BUFS() operation. It is
783 * called internally by VB2 by an API-specific handler, like
784 * ``videobuf2-v4l2.h``.
788 * #) verifies parameter sanity;
789 * #) calls the &vb2_ops->queue_setup queue operation;
790 * #) performs any necessary memory allocations.
792 * Return: returns zero on success; an error code otherwise.
794 int vb2_core_create_bufs(struct vb2_queue *q, enum vb2_memory memory,
796 unsigned int requested_planes,
797 const unsigned int requested_sizes[]);
800 * vb2_core_prepare_buf() - Pass ownership of a buffer from userspace
802 * @q: pointer to &struct vb2_queue with videobuf2 queue.
803 * @index: id number of the buffer.
804 * @pb: buffer structure passed from userspace to
805 * &v4l2_ioctl_ops->vidioc_prepare_buf handler in driver.
807 * Videobuf2 core helper to implement VIDIOC_PREPARE_BUF() operation. It is
808 * called internally by VB2 by an API-specific handler, like
809 * ``videobuf2-v4l2.h``.
811 * The passed buffer should have been verified.
813 * This function calls vb2_ops->buf_prepare callback in the driver
814 * (if provided), in which driver-specific buffer initialization can
817 * Return: returns zero on success; an error code otherwise.
819 int vb2_core_prepare_buf(struct vb2_queue *q, unsigned int index, void *pb);
822 * vb2_core_qbuf() - Queue a buffer from userspace
824 * @q: pointer to &struct vb2_queue with videobuf2 queue.
825 * @index: id number of the buffer
826 * @pb: buffer structure passed from userspace to
827 * v4l2_ioctl_ops->vidioc_qbuf handler in driver
828 * @req: pointer to &struct media_request, may be NULL.
830 * Videobuf2 core helper to implement VIDIOC_QBUF() operation. It is called
831 * internally by VB2 by an API-specific handler, like ``videobuf2-v4l2.h``.
835 * #) If @req is non-NULL, then the buffer will be bound to this
836 * media request and it returns. The buffer will be prepared and
837 * queued to the driver (i.e. the next two steps) when the request
839 * #) if necessary, calls &vb2_ops->buf_prepare callback in the driver
840 * (if provided), in which driver-specific buffer initialization can
842 * #) if streaming is on, queues the buffer in driver by the means of
843 * &vb2_ops->buf_queue callback for processing.
845 * Return: returns zero on success; an error code otherwise.
847 int vb2_core_qbuf(struct vb2_queue *q, unsigned int index, void *pb,
848 struct media_request *req);
851 * vb2_core_dqbuf() - Dequeue a buffer to the userspace
852 * @q: pointer to &struct vb2_queue with videobuf2 queue
853 * @pindex: pointer to the buffer index. May be NULL
854 * @pb: buffer structure passed from userspace to
855 * v4l2_ioctl_ops->vidioc_dqbuf handler in driver.
856 * @nonblocking: if true, this call will not sleep waiting for a buffer if no
857 * buffers ready for dequeuing are present. Normally the driver
858 * would be passing (file->f_flags & O_NONBLOCK) here.
860 * Videobuf2 core helper to implement VIDIOC_DQBUF() operation. It is called
861 * internally by VB2 by an API-specific handler, like ``videobuf2-v4l2.h``.
865 * #) calls buf_finish callback in the driver (if provided), in which
866 * driver can perform any additional operations that may be required before
867 * returning the buffer to userspace, such as cache sync,
868 * #) the buffer struct members are filled with relevant information for
871 * Return: returns zero on success; an error code otherwise.
873 int vb2_core_dqbuf(struct vb2_queue *q, unsigned int *pindex, void *pb,
877 * vb2_core_streamon() - Implements VB2 stream ON logic
879 * @q: pointer to &struct vb2_queue with videobuf2 queue
880 * @type: type of the queue to be started.
881 * For V4L2, this is defined by &enum v4l2_buf_type type.
883 * Videobuf2 core helper to implement VIDIOC_STREAMON() operation. It is called
884 * internally by VB2 by an API-specific handler, like ``videobuf2-v4l2.h``.
886 * Return: returns zero on success; an error code otherwise.
888 int vb2_core_streamon(struct vb2_queue *q, unsigned int type);
891 * vb2_core_streamoff() - Implements VB2 stream OFF logic
893 * @q: pointer to &struct vb2_queue with videobuf2 queue
894 * @type: type of the queue to be started.
895 * For V4L2, this is defined by &enum v4l2_buf_type type.
897 * Videobuf2 core helper to implement VIDIOC_STREAMOFF() operation. It is
898 * called internally by VB2 by an API-specific handler, like
899 * ``videobuf2-v4l2.h``.
901 * Return: returns zero on success; an error code otherwise.
903 int vb2_core_streamoff(struct vb2_queue *q, unsigned int type);
906 * vb2_core_expbuf() - Export a buffer as a file descriptor.
907 * @q: pointer to &struct vb2_queue with videobuf2 queue.
908 * @fd: pointer to the file descriptor associated with DMABUF
910 * @type: buffer type.
911 * @index: id number of the buffer.
912 * @plane: index of the plane to be exported, 0 for single plane queues
913 * @flags: file flags for newly created file, as defined at
914 * include/uapi/asm-generic/fcntl.h.
915 * Currently, the only used flag is %O_CLOEXEC.
916 * is supported, refer to manual of open syscall for more details.
919 * Videobuf2 core helper to implement VIDIOC_EXPBUF() operation. It is called
920 * internally by VB2 by an API-specific handler, like ``videobuf2-v4l2.h``.
922 * Return: returns zero on success; an error code otherwise.
924 int vb2_core_expbuf(struct vb2_queue *q, int *fd, unsigned int type,
925 unsigned int index, unsigned int plane, unsigned int flags);
928 * vb2_core_queue_init() - initialize a videobuf2 queue
929 * @q: pointer to &struct vb2_queue with videobuf2 queue.
930 * This structure should be allocated in driver
932 * The &vb2_queue structure should be allocated by the driver. The driver is
933 * responsible of clearing it's content and setting initial values for some
934 * required entries before calling this function.
938 * The following fields at @q should be set before calling this function:
939 * &vb2_queue->ops, &vb2_queue->mem_ops, &vb2_queue->type.
941 int vb2_core_queue_init(struct vb2_queue *q);
944 * vb2_core_queue_release() - stop streaming, release the queue and free memory
945 * @q: pointer to &struct vb2_queue with videobuf2 queue.
947 * This function stops streaming and performs necessary clean ups, including
948 * freeing video buffer memory. The driver is responsible for freeing
949 * the &struct vb2_queue itself.
951 void vb2_core_queue_release(struct vb2_queue *q);
954 * vb2_queue_error() - signal a fatal error on the queue
955 * @q: pointer to &struct vb2_queue with videobuf2 queue.
957 * Flag that a fatal unrecoverable error has occurred and wake up all processes
958 * waiting on the queue. Polling will now set %EPOLLERR and queuing and dequeuing
959 * buffers will return %-EIO.
961 * The error flag will be cleared when canceling the queue, either from
962 * vb2_streamoff() or vb2_queue_release(). Drivers should thus not call this
963 * function before starting the stream, otherwise the error flag will remain set
964 * until the queue is released when closing the device node.
966 void vb2_queue_error(struct vb2_queue *q);
969 * vb2_mmap() - map video buffers into application address space.
970 * @q: pointer to &struct vb2_queue with videobuf2 queue.
971 * @vma: pointer to &struct vm_area_struct with the vma passed
972 * to the mmap file operation handler in the driver.
974 * Should be called from mmap file operation handler of a driver.
975 * This function maps one plane of one of the available video buffers to
976 * userspace. To map whole video memory allocated on reqbufs, this function
977 * has to be called once per each plane per each buffer previously allocated.
979 * When the userspace application calls mmap, it passes to it an offset returned
980 * to it earlier by the means of &v4l2_ioctl_ops->vidioc_querybuf handler.
981 * That offset acts as a "cookie", which is then used to identify the plane
984 * This function finds a plane with a matching offset and a mapping is performed
985 * by the means of a provided memory operation.
987 * The return values from this function are intended to be directly returned
988 * from the mmap handler in driver.
990 int vb2_mmap(struct vb2_queue *q, struct vm_area_struct *vma);
994 * vb2_get_unmapped_area - map video buffers into application address space.
995 * @q: pointer to &struct vb2_queue with videobuf2 queue.
996 * @addr: memory address.
998 * @pgoff: page offset.
999 * @flags: memory flags.
1001 * This function is used in noMMU platforms to propose address mapping
1002 * for a given buffer. It's intended to be used as a handler for the
1003 * &file_operations->get_unmapped_area operation.
1005 * This is called by the mmap() syscall routines will call this
1006 * to get a proposed address for the mapping, when ``!CONFIG_MMU``.
1008 unsigned long vb2_get_unmapped_area(struct vb2_queue *q,
1011 unsigned long pgoff,
1012 unsigned long flags);
1016 * vb2_core_poll() - implements poll syscall() logic.
1017 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1018 * @file: &struct file argument passed to the poll
1019 * file operation handler.
1020 * @wait: &poll_table wait argument passed to the poll
1021 * file operation handler.
1023 * This function implements poll file operation handler for a driver.
1024 * For CAPTURE queues, if a buffer is ready to be dequeued, the userspace will
1025 * be informed that the file descriptor of a video device is available for
1027 * For OUTPUT queues, if a buffer is ready to be dequeued, the file descriptor
1028 * will be reported as available for writing.
1030 * The return values from this function are intended to be directly returned
1031 * from poll handler in driver.
1033 __poll_t vb2_core_poll(struct vb2_queue *q, struct file *file,
1037 * vb2_read() - implements read() syscall logic.
1038 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1039 * @data: pointed to target userspace buffer
1040 * @count: number of bytes to read
1041 * @ppos: file handle position tracking pointer
1042 * @nonblock: mode selector (1 means blocking calls, 0 means nonblocking)
1044 size_t vb2_read(struct vb2_queue *q, char __user *data, size_t count,
1045 loff_t *ppos, int nonblock);
1047 * vb2_write() - implements write() syscall logic.
1048 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1049 * @data: pointed to target userspace buffer
1050 * @count: number of bytes to write
1051 * @ppos: file handle position tracking pointer
1052 * @nonblock: mode selector (1 means blocking calls, 0 means nonblocking)
1054 size_t vb2_write(struct vb2_queue *q, const char __user *data, size_t count,
1055 loff_t *ppos, int nonblock);
1058 * typedef vb2_thread_fnc - callback function for use with vb2_thread.
1060 * @vb: pointer to struct &vb2_buffer.
1061 * @priv: pointer to a private data.
1063 * This is called whenever a buffer is dequeued in the thread.
1065 typedef int (*vb2_thread_fnc)(struct vb2_buffer *vb, void *priv);
1068 * vb2_thread_start() - start a thread for the given queue.
1069 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1070 * @fnc: &vb2_thread_fnc callback function.
1071 * @priv: priv pointer passed to the callback function.
1072 * @thread_name:the name of the thread. This will be prefixed with "vb2-".
1074 * This starts a thread that will queue and dequeue until an error occurs
1075 * or vb2_thread_stop() is called.
1079 * This function should not be used for anything else but the videobuf2-dvb
1080 * support. If you think you have another good use-case for this, then please
1081 * contact the linux-media mailing list first.
1083 int vb2_thread_start(struct vb2_queue *q, vb2_thread_fnc fnc, void *priv,
1084 const char *thread_name);
1087 * vb2_thread_stop() - stop the thread for the given queue.
1088 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1090 int vb2_thread_stop(struct vb2_queue *q);
1093 * vb2_is_streaming() - return streaming status of the queue.
1094 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1096 static inline bool vb2_is_streaming(struct vb2_queue *q)
1098 return q->streaming;
1102 * vb2_fileio_is_active() - return true if fileio is active.
1103 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1105 * This returns true if read() or write() is used to stream the data
1106 * as opposed to stream I/O. This is almost never an important distinction,
1107 * except in rare cases. One such case is that using read() or write() to
1108 * stream a format using %V4L2_FIELD_ALTERNATE is not allowed since there
1109 * is no way you can pass the field information of each buffer to/from
1110 * userspace. A driver that supports this field format should check for
1111 * this in the &vb2_ops->queue_setup op and reject it if this function returns
1114 static inline bool vb2_fileio_is_active(struct vb2_queue *q)
1120 * vb2_is_busy() - return busy status of the queue.
1121 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1123 * This function checks if queue has any buffers allocated.
1125 static inline bool vb2_is_busy(struct vb2_queue *q)
1127 return (q->num_buffers > 0);
1131 * vb2_get_drv_priv() - return driver private data associated with the queue.
1132 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1134 static inline void *vb2_get_drv_priv(struct vb2_queue *q)
1140 * vb2_set_plane_payload() - set bytesused for the plane @plane_no.
1141 * @vb: pointer to &struct vb2_buffer to which the plane in
1142 * question belongs to.
1143 * @plane_no: plane number for which payload should be set.
1144 * @size: payload in bytes.
1146 static inline void vb2_set_plane_payload(struct vb2_buffer *vb,
1147 unsigned int plane_no, unsigned long size)
1149 if (plane_no < vb->num_planes)
1150 vb->planes[plane_no].bytesused = size;
1154 * vb2_get_plane_payload() - get bytesused for the plane plane_no
1155 * @vb: pointer to &struct vb2_buffer to which the plane in
1156 * question belongs to.
1157 * @plane_no: plane number for which payload should be set.
1159 static inline unsigned long vb2_get_plane_payload(struct vb2_buffer *vb,
1160 unsigned int plane_no)
1162 if (plane_no < vb->num_planes)
1163 return vb->planes[plane_no].bytesused;
1168 * vb2_plane_size() - return plane size in bytes.
1169 * @vb: pointer to &struct vb2_buffer to which the plane in
1170 * question belongs to.
1171 * @plane_no: plane number for which size should be returned.
1173 static inline unsigned long
1174 vb2_plane_size(struct vb2_buffer *vb, unsigned int plane_no)
1176 if (plane_no < vb->num_planes)
1177 return vb->planes[plane_no].length;
1182 * vb2_start_streaming_called() - return streaming status of driver.
1183 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1185 static inline bool vb2_start_streaming_called(struct vb2_queue *q)
1187 return q->start_streaming_called;
1191 * vb2_clear_last_buffer_dequeued() - clear last buffer dequeued flag of queue.
1192 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1194 static inline void vb2_clear_last_buffer_dequeued(struct vb2_queue *q)
1196 q->last_buffer_dequeued = false;
1200 * vb2_get_buffer() - get a buffer from a queue
1201 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1202 * @index: buffer index
1204 * This function obtains a buffer from a queue, by its index.
1205 * Keep in mind that there is no refcounting involved in this
1206 * operation, so the buffer lifetime should be taken into
1209 static inline struct vb2_buffer *vb2_get_buffer(struct vb2_queue *q,
1212 if (index < q->num_buffers)
1213 return q->bufs[index];
1218 * The following functions are not part of the vb2 core API, but are useful
1219 * functions for videobuf2-*.
1223 * vb2_buffer_in_use() - return true if the buffer is in use and
1224 * the queue cannot be freed (by the means of VIDIOC_REQBUFS(0)) call.
1226 * @vb: buffer for which plane size should be returned.
1227 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1229 bool vb2_buffer_in_use(struct vb2_queue *q, struct vb2_buffer *vb);
1232 * vb2_verify_memory_type() - Check whether the memory type and buffer type
1233 * passed to a buffer operation are compatible with the queue.
1235 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1236 * @memory: memory model, as defined by enum &vb2_memory.
1237 * @type: private buffer type whose content is defined by the vb2-core
1238 * caller. For example, for V4L2, it should match
1239 * the types defined on enum &v4l2_buf_type.
1241 int vb2_verify_memory_type(struct vb2_queue *q,
1242 enum vb2_memory memory, unsigned int type);
1245 * vb2_request_object_is_buffer() - return true if the object is a buffer
1247 * @obj: the request object.
1249 bool vb2_request_object_is_buffer(struct media_request_object *obj);
1252 * vb2_request_buffer_cnt() - return the number of buffers in the request
1254 * @req: the request.
1256 unsigned int vb2_request_buffer_cnt(struct media_request *req);
1258 #endif /* _MEDIA_VIDEOBUF2_CORE_H */