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>
22 #define VB2_MAX_FRAME (32)
23 #define VB2_MAX_PLANES (8)
26 * enum vb2_memory - type of memory model used to make the buffers visible
29 * @VB2_MEMORY_UNKNOWN: Buffer status is unknown or it is not used yet on
31 * @VB2_MEMORY_MMAP: The buffers are allocated by the Kernel and it is
32 * memory mapped via mmap() ioctl. This model is
33 * also used when the user is using the buffers via
34 * read() or write() system calls.
35 * @VB2_MEMORY_USERPTR: The buffers was allocated in userspace and it is
36 * memory mapped via mmap() ioctl.
37 * @VB2_MEMORY_DMABUF: The buffers are passed to userspace via DMA buffer.
40 VB2_MEMORY_UNKNOWN = 0,
42 VB2_MEMORY_USERPTR = 2,
43 VB2_MEMORY_DMABUF = 4,
46 struct vb2_fileio_data;
47 struct vb2_threadio_data;
50 * struct vb2_mem_ops - memory handling/memory allocator operations.
51 * @alloc: allocate video memory and, optionally, allocator private data,
52 * return ERR_PTR() on failure or a pointer to allocator private,
53 * per-buffer data on success; the returned private structure
54 * will then be passed as @buf_priv argument to other ops in this
55 * structure. Additional gfp_flags to use when allocating the
56 * are also passed to this operation. These flags are from the
57 * gfp_flags field of vb2_queue. The size argument to this function
58 * shall be *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 * videobuf 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
75 * @attach_dmabuf: attach a shared &struct dma_buf for a hardware operation;
76 * used for DMABUF memory types; dev is the alloc device
77 * dbuf is the shared dma_buf; returns ERR_PTR() on failure;
78 * allocator private per-buffer structure on success;
79 * this needs to be used for further accesses to the buffer.
80 * @detach_dmabuf: inform the exporter of the buffer that the current DMABUF
81 * buffer is no longer used; the @buf_priv argument is the
82 * allocator private per-buffer structure previously returned
83 * from the attach_dmabuf callback.
84 * @map_dmabuf: request for access to the dmabuf from allocator; the allocator
85 * of dmabuf is informed that this driver is going to use the
87 * @unmap_dmabuf: releases access control to the dmabuf - allocator is notified
88 * that this driver is done using the dmabuf for now.
89 * @prepare: called every time the buffer is passed from userspace to the
90 * driver, useful for cache synchronisation, optional.
91 * @finish: called every time the buffer is passed back from the driver
92 * to the userspace, also optional.
93 * @vaddr: return a kernel virtual address to a given memory buffer
94 * associated with the passed private structure or NULL if no
95 * such mapping exists.
96 * @cookie: return allocator specific cookie for a given memory buffer
97 * associated with the passed private structure or NULL if not
99 * @num_users: return the current number of users of a memory buffer;
100 * return 1 if the videobuf 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.
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.
109 * #) Required ops for USERPTR types: get_userptr, put_userptr.
111 * #) Required ops for MMAP types: alloc, put, num_users, mmap.
113 * #) Required ops for read/write access types: alloc, put, num_users, vaddr.
115 * #) Required ops for DMABUF types: attach_dmabuf, detach_dmabuf,
116 * map_dmabuf, unmap_dmabuf.
119 void *(*alloc)(struct device *dev, unsigned long attrs,
121 enum dma_data_direction dma_dir,
123 void (*put)(void *buf_priv);
124 struct dma_buf *(*get_dmabuf)(void *buf_priv, unsigned long flags);
126 void *(*get_userptr)(struct device *dev, unsigned long vaddr,
128 enum dma_data_direction dma_dir);
129 void (*put_userptr)(void *buf_priv);
131 void (*prepare)(void *buf_priv);
132 void (*finish)(void *buf_priv);
134 void *(*attach_dmabuf)(struct device *dev,
135 struct dma_buf *dbuf,
137 enum dma_data_direction dma_dir);
138 void (*detach_dmabuf)(void *buf_priv);
139 int (*map_dmabuf)(void *buf_priv);
140 void (*unmap_dmabuf)(void *buf_priv);
142 void *(*vaddr)(void *buf_priv);
143 void *(*cookie)(void *buf_priv);
145 unsigned int (*num_users)(void *buf_priv);
147 int (*mmap)(void *buf_priv, struct vm_area_struct *vma);
151 * struct vb2_plane - plane information.
152 * @mem_priv: private data with this plane.
153 * @dbuf: dma_buf - shared buffer object.
154 * @dbuf_mapped: flag to show whether dbuf is mapped or not
155 * @bytesused: number of bytes occupied by data in the plane (payload).
156 * @length: size of this plane (NOT the payload) in bytes.
157 * @min_length: minimum required size of this plane (NOT the payload) in bytes.
158 * @length is always greater or equal to @min_length.
159 * @m: Union with memtype-specific data.
160 * @m.offset: when memory in the associated struct vb2_buffer is
161 * %VB2_MEMORY_MMAP, equals the offset from the start of
162 * the device memory for this plane (or is a "cookie" that
163 * should be passed to mmap() called on the video node).
164 * @m.userptr: when memory is %VB2_MEMORY_USERPTR, a userspace pointer
165 * pointing to this plane.
166 * @m.fd: when memory is %VB2_MEMORY_DMABUF, a userspace file
167 * descriptor associated with this plane.
168 * @data_offset: offset in the plane to the start of data; usually 0,
169 * unless there is a header in front of the data.
171 * Should contain enough information to be able to cover all the fields
172 * of &struct v4l2_plane at videodev2.h.
176 struct dma_buf *dbuf;
177 unsigned int dbuf_mapped;
178 unsigned int bytesused;
180 unsigned int min_length;
183 unsigned long userptr;
186 unsigned int data_offset;
190 * enum vb2_io_modes - queue access methods.
191 * @VB2_MMAP: driver supports MMAP with streaming API.
192 * @VB2_USERPTR: driver supports USERPTR with streaming API.
193 * @VB2_READ: driver supports read() style access.
194 * @VB2_WRITE: driver supports write() style access.
195 * @VB2_DMABUF: driver supports DMABUF with streaming API.
199 VB2_USERPTR = BIT(1),
206 * enum vb2_buffer_state - current video buffer state.
207 * @VB2_BUF_STATE_DEQUEUED: buffer under userspace control.
208 * @VB2_BUF_STATE_IN_REQUEST: buffer is queued in media request.
209 * @VB2_BUF_STATE_PREPARING: buffer is being prepared in videobuf.
210 * @VB2_BUF_STATE_QUEUED: buffer queued in videobuf, but not in driver.
211 * @VB2_BUF_STATE_ACTIVE: buffer queued in driver and possibly used
212 * in a hardware operation.
213 * @VB2_BUF_STATE_DONE: buffer returned from driver to videobuf, but
214 * not yet dequeued to userspace.
215 * @VB2_BUF_STATE_ERROR: same as above, but the operation on the buffer
216 * has ended with an error, which will be reported
217 * to the userspace when it is dequeued.
219 enum vb2_buffer_state {
220 VB2_BUF_STATE_DEQUEUED,
221 VB2_BUF_STATE_IN_REQUEST,
222 VB2_BUF_STATE_PREPARING,
223 VB2_BUF_STATE_QUEUED,
224 VB2_BUF_STATE_ACTIVE,
232 * struct vb2_buffer - represents a video buffer.
233 * @vb2_queue: pointer to &struct vb2_queue with the queue to
234 * which this driver belongs.
235 * @index: id number of the buffer.
236 * @type: buffer type.
237 * @memory: the method, in which the actual data is passed.
238 * @num_planes: number of planes in the buffer
239 * on an internal driver queue.
240 * @timestamp: frame timestamp in ns.
241 * @request: the request this buffer is associated with.
242 * @req_obj: used to bind this buffer to a request. This
243 * request object has a refcount.
246 struct vb2_queue *vb2_queue;
250 unsigned int num_planes;
252 struct media_request *request;
253 struct media_request_object req_obj;
255 /* private: internal use only
257 * state: current buffer state; do not change
258 * synced: this buffer has been synced for DMA, i.e. the
259 * 'prepare' memop was called. It is cleared again
260 * after the 'finish' memop is called.
261 * prepared: this buffer has been prepared, i.e. the
262 * buf_prepare op was called. It is cleared again
263 * after the 'buf_finish' op is called.
264 * copied_timestamp: the timestamp of this capture buffer was copied
265 * from an output buffer.
266 * need_cache_sync_on_prepare: when set buffer's ->prepare() function
267 * performs cache sync/invalidation.
268 * need_cache_sync_on_finish: when set buffer's ->finish() function
269 * performs cache sync/invalidation.
270 * queued_entry: entry on the queued buffers list, which holds
271 * all buffers queued from userspace
272 * done_entry: entry on the list that stores all buffers ready
273 * to be dequeued to userspace
274 * vb2_plane: per-plane information; do not change
276 enum vb2_buffer_state state;
277 unsigned int synced:1;
278 unsigned int prepared:1;
279 unsigned int copied_timestamp:1;
280 unsigned int need_cache_sync_on_prepare:1;
281 unsigned int need_cache_sync_on_finish:1;
283 struct vb2_plane planes[VB2_MAX_PLANES];
284 struct list_head queued_entry;
285 struct list_head done_entry;
286 #ifdef CONFIG_VIDEO_ADV_DEBUG
288 * Counters for how often these buffer-related ops are
289 * called. Used to check for unbalanced ops.
293 u32 cnt_mem_get_dmabuf;
294 u32 cnt_mem_get_userptr;
295 u32 cnt_mem_put_userptr;
298 u32 cnt_mem_attach_dmabuf;
299 u32 cnt_mem_detach_dmabuf;
300 u32 cnt_mem_map_dmabuf;
301 u32 cnt_mem_unmap_dmabuf;
304 u32 cnt_mem_num_users;
307 u32 cnt_buf_out_validate;
313 u32 cnt_buf_request_complete;
315 /* This counts the number of calls to vb2_buffer_done() */
321 * struct vb2_ops - driver-specific callbacks.
323 * These operations are not called from interrupt context except where
324 * mentioned specifically.
326 * @queue_setup: called from VIDIOC_REQBUFS() and VIDIOC_CREATE_BUFS()
327 * handlers before memory allocation. It can be called
328 * twice: if the original number of requested buffers
329 * could not be allocated, then it will be called a
330 * second time with the actually allocated number of
331 * buffers to verify if that is OK.
332 * The driver should return the required number of buffers
333 * in \*num_buffers, the required number of planes per
334 * buffer in \*num_planes, the size of each plane should be
335 * set in the sizes\[\] array and optional per-plane
336 * allocator specific device in the alloc_devs\[\] array.
337 * When called from VIDIOC_REQBUFS(), \*num_planes == 0,
338 * the driver has to use the currently configured format to
339 * determine the plane sizes and \*num_buffers is the total
340 * number of buffers that are being allocated. When called
341 * from VIDIOC_CREATE_BUFS(), \*num_planes != 0 and it
342 * describes the requested number of planes and sizes\[\]
343 * contains the requested plane sizes. In this case
344 * \*num_buffers are being allocated additionally to
345 * q->num_buffers. If either \*num_planes or the requested
346 * sizes are invalid callback must return %-EINVAL.
347 * @wait_prepare: release any locks taken while calling vb2 functions;
348 * it is called before an ioctl needs to wait for a new
349 * buffer to arrive; required to avoid a deadlock in
350 * blocking access type.
351 * @wait_finish: reacquire all locks released in the previous callback;
352 * required to continue operation after sleeping while
353 * waiting for a new buffer to arrive.
354 * @buf_out_validate: called when the output buffer is prepared or queued
355 * to a request; drivers can use this to validate
356 * userspace-provided information; this is required only
358 * @buf_init: called once after allocating a buffer (in MMAP case)
359 * or after acquiring a new USERPTR buffer; drivers may
360 * perform additional buffer-related initialization;
361 * initialization failure (return != 0) will prevent
362 * queue setup from completing successfully; optional.
363 * @buf_prepare: called every time the buffer is queued from userspace
364 * and from the VIDIOC_PREPARE_BUF() ioctl; drivers may
365 * perform any initialization required before each
366 * hardware operation in this callback; drivers can
367 * access/modify the buffer here as it is still synced for
368 * the CPU; drivers that support VIDIOC_CREATE_BUFS() must
369 * also validate the buffer size; if an error is returned,
370 * the buffer will not be queued in driver; optional.
371 * @buf_finish: called before every dequeue of the buffer back to
372 * userspace; the buffer is synced for the CPU, so drivers
373 * can access/modify the buffer contents; drivers may
374 * perform any operations required before userspace
375 * accesses the buffer; optional. The buffer state can be
376 * one of the following: %DONE and %ERROR occur while
377 * streaming is in progress, and the %PREPARED state occurs
378 * when the queue has been canceled and all pending
379 * buffers are being returned to their default %DEQUEUED
380 * state. Typically you only have to do something if the
381 * state is %VB2_BUF_STATE_DONE, since in all other cases
382 * the buffer contents will be ignored anyway.
383 * @buf_cleanup: called once before the buffer is freed; drivers may
384 * perform any additional cleanup; optional.
385 * @start_streaming: called once to enter 'streaming' state; the driver may
386 * receive buffers with @buf_queue callback
387 * before @start_streaming is called; the driver gets the
388 * number of already queued buffers in count parameter;
389 * driver can return an error if hardware fails, in that
390 * case all buffers that have been already given by
391 * the @buf_queue callback are to be returned by the driver
392 * by calling vb2_buffer_done() with %VB2_BUF_STATE_QUEUED.
393 * If you need a minimum number of buffers before you can
394 * start streaming, then set
395 * &vb2_queue->min_buffers_needed. If that is non-zero
396 * then @start_streaming won't be called until at least
397 * that many buffers have been queued up by userspace.
398 * @stop_streaming: called when 'streaming' state must be disabled; driver
399 * should stop any DMA transactions or wait until they
400 * finish and give back all buffers it got from &buf_queue
401 * callback by calling vb2_buffer_done() with either
402 * %VB2_BUF_STATE_DONE or %VB2_BUF_STATE_ERROR; may use
403 * vb2_wait_for_all_buffers() function
404 * @buf_queue: passes buffer vb to the driver; driver may start
405 * hardware operation on this buffer; driver should give
406 * the buffer back by calling vb2_buffer_done() function;
407 * it is always called after calling VIDIOC_STREAMON()
408 * ioctl; might be called before @start_streaming callback
409 * if user pre-queued buffers before calling
411 * @buf_request_complete: a buffer that was never queued to the driver but is
412 * associated with a queued request was canceled.
413 * The driver will have to mark associated objects in the
414 * request as completed; required if requests are
418 int (*queue_setup)(struct vb2_queue *q,
419 unsigned int *num_buffers, unsigned int *num_planes,
420 unsigned int sizes[], struct device *alloc_devs[]);
422 void (*wait_prepare)(struct vb2_queue *q);
423 void (*wait_finish)(struct vb2_queue *q);
425 int (*buf_out_validate)(struct vb2_buffer *vb);
426 int (*buf_init)(struct vb2_buffer *vb);
427 int (*buf_prepare)(struct vb2_buffer *vb);
428 void (*buf_finish)(struct vb2_buffer *vb);
429 void (*buf_cleanup)(struct vb2_buffer *vb);
431 int (*start_streaming)(struct vb2_queue *q, unsigned int count);
432 void (*stop_streaming)(struct vb2_queue *q);
434 void (*buf_queue)(struct vb2_buffer *vb);
436 void (*buf_request_complete)(struct vb2_buffer *vb);
440 * struct vb2_buf_ops - driver-specific callbacks.
442 * @verify_planes_array: Verify that a given user space structure contains
443 * enough planes for the buffer. This is called
444 * for each dequeued buffer.
445 * @init_buffer: given a &vb2_buffer initialize the extra data after
447 * For V4L2 this is a &struct vb2_v4l2_buffer.
448 * @fill_user_buffer: given a &vb2_buffer fill in the userspace structure.
449 * For V4L2 this is a &struct v4l2_buffer.
450 * @fill_vb2_buffer: given a userspace structure, fill in the &vb2_buffer.
451 * If the userspace structure is invalid, then this op
452 * will return an error.
453 * @copy_timestamp: copy the timestamp from a userspace structure to
454 * the &struct vb2_buffer.
457 int (*verify_planes_array)(struct vb2_buffer *vb, const void *pb);
458 void (*init_buffer)(struct vb2_buffer *vb);
459 void (*fill_user_buffer)(struct vb2_buffer *vb, void *pb);
460 int (*fill_vb2_buffer)(struct vb2_buffer *vb, struct vb2_plane *planes);
461 void (*copy_timestamp)(struct vb2_buffer *vb, const void *pb);
465 * struct vb2_queue - a videobuf queue.
467 * @type: private buffer type whose content is defined by the vb2-core
468 * caller. For example, for V4L2, it should match
469 * the types defined on &enum v4l2_buf_type.
470 * @io_modes: supported io methods (see &enum vb2_io_modes).
471 * @alloc_devs: &struct device memory type/allocator-specific per-plane device
472 * @dev: device to use for the default allocation context if the driver
473 * doesn't fill in the @alloc_devs array.
474 * @dma_attrs: DMA attributes to use for the DMA.
475 * @bidirectional: when this flag is set the DMA direction for the buffers of
476 * this queue will be overridden with %DMA_BIDIRECTIONAL direction.
477 * This is useful in cases where the hardware (firmware) writes to
478 * a buffer which is mapped as read (%DMA_TO_DEVICE), or reads from
479 * buffer which is mapped for write (%DMA_FROM_DEVICE) in order
480 * to satisfy some internal hardware restrictions or adds a padding
481 * needed by the processing algorithm. In case the DMA mapping is
482 * not bidirectional but the hardware (firmware) trying to access
483 * the buffer (in the opposite direction) this could lead to an
484 * IOMMU protection faults.
485 * @fileio_read_once: report EOF after reading the first buffer
486 * @fileio_write_immediately: queue buffer after each write() call
487 * @allow_zero_bytesused: allow bytesused == 0 to be passed to the driver
488 * @quirk_poll_must_check_waiting_for_buffers: Return %EPOLLERR at poll when QBUF
489 * has not been called. This is a vb1 idiom that has been adopted
491 * @supports_requests: this queue supports the Request API.
492 * @requires_requests: this queue requires the Request API. If this is set to 1,
493 * then supports_requests must be set to 1 as well.
494 * @uses_qbuf: qbuf was used directly for this queue. Set to 1 the first
495 * time this is called. Set to 0 when the queue is canceled.
496 * If this is 1, then you cannot queue buffers from a request.
497 * @uses_requests: requests are used for this queue. Set to 1 the first time
498 * a request is queued. Set to 0 when the queue is canceled.
499 * If this is 1, then you cannot queue buffers directly.
500 * @allow_cache_hints: when set user-space can pass cache management hints in
501 * order to skip cache flush/invalidation on ->prepare() or/and
503 * @lock: pointer to a mutex that protects the &struct vb2_queue. The
504 * driver can set this to a mutex to let the v4l2 core serialize
505 * the queuing ioctls. If the driver wants to handle locking
506 * itself, then this should be set to NULL. This lock is not used
507 * by the videobuf2 core API.
508 * @owner: The filehandle that 'owns' the buffers, i.e. the filehandle
509 * that called reqbufs, create_buffers or started fileio.
510 * This field is not used by the videobuf2 core API, but it allows
511 * drivers to easily associate an owner filehandle with the queue.
512 * @ops: driver-specific callbacks
513 * @mem_ops: memory allocator specific callbacks
514 * @buf_ops: callbacks to deliver buffer information.
515 * between user-space and kernel-space.
516 * @drv_priv: driver private data.
517 * @subsystem_flags: Flags specific to the subsystem (V4L2/DVB/etc.). Not used
519 * @buf_struct_size: size of the driver-specific buffer structure;
520 * "0" indicates the driver doesn't want to use a custom buffer
521 * structure type. In that case a subsystem-specific struct
522 * will be used (in the case of V4L2 that is
523 * ``sizeof(struct vb2_v4l2_buffer)``). The first field of the
524 * driver-specific buffer structure must be the subsystem-specific
525 * struct (vb2_v4l2_buffer in the case of V4L2).
526 * @timestamp_flags: Timestamp flags; ``V4L2_BUF_FLAG_TIMESTAMP_*`` and
527 * ``V4L2_BUF_FLAG_TSTAMP_SRC_*``
528 * @gfp_flags: additional gfp flags used when allocating the buffers.
529 * Typically this is 0, but it may be e.g. %GFP_DMA or %__GFP_DMA32
530 * to force the buffer allocation to a specific memory zone.
531 * @min_buffers_needed: the minimum number of buffers needed before
532 * @start_streaming can be called. Used when a DMA engine
533 * cannot be started unless at least this number of buffers
534 * have been queued into the driver.
537 * Private elements (won't appear at the uAPI book):
538 * @mmap_lock: private mutex used when buffers are allocated/freed/mmapped
539 * @memory: current memory type used
540 * @dma_dir: DMA mapping direction.
541 * @bufs: videobuf buffer structures
542 * @num_buffers: number of allocated/used buffers
543 * @queued_list: list of buffers currently queued from userspace
544 * @queued_count: number of buffers queued and ready for streaming.
545 * @owned_by_drv_count: number of buffers owned by the driver
546 * @done_list: list of buffers ready to be dequeued to userspace
547 * @done_lock: lock to protect done_list list
548 * @done_wq: waitqueue for processes waiting for buffers ready to be dequeued
549 * @streaming: current streaming state
550 * @start_streaming_called: @start_streaming was called successfully and we
552 * @error: a fatal error occurred on the queue
553 * @waiting_for_buffers: used in poll() to check if vb2 is still waiting for
554 * buffers. Only set for capture queues if qbuf has not yet been
555 * called since poll() needs to return %EPOLLERR in that situation.
556 * @is_multiplanar: set if buffer type is multiplanar
557 * @is_output: set if buffer type is output
558 * @copy_timestamp: set if vb2-core should set timestamps
559 * @last_buffer_dequeued: used in poll() and DQBUF to immediately return if the
560 * last decoded buffer was already dequeued. Set for capture queues
561 * when a buffer with the %V4L2_BUF_FLAG_LAST is dequeued.
562 * @fileio: file io emulator internal data, used only if emulator is active
563 * @threadio: thread io internal data, used only if thread is active
564 * @name: queue name, used for logging purpose. Initialized automatically
565 * if left empty by drivers.
569 unsigned int io_modes;
571 unsigned long dma_attrs;
572 unsigned int bidirectional:1;
573 unsigned int fileio_read_once:1;
574 unsigned int fileio_write_immediately:1;
575 unsigned int allow_zero_bytesused:1;
576 unsigned int quirk_poll_must_check_waiting_for_buffers:1;
577 unsigned int supports_requests:1;
578 unsigned int requires_requests:1;
579 unsigned int uses_qbuf:1;
580 unsigned int uses_requests:1;
581 unsigned int allow_cache_hints:1;
586 const struct vb2_ops *ops;
587 const struct vb2_mem_ops *mem_ops;
588 const struct vb2_buf_ops *buf_ops;
592 unsigned int buf_struct_size;
595 u32 min_buffers_needed;
597 struct device *alloc_devs[VB2_MAX_PLANES];
599 /* private: internal use only */
600 struct mutex mmap_lock;
602 enum dma_data_direction dma_dir;
603 struct vb2_buffer *bufs[VB2_MAX_FRAME];
604 unsigned int num_buffers;
606 struct list_head queued_list;
607 unsigned int queued_count;
609 atomic_t owned_by_drv_count;
610 struct list_head done_list;
611 spinlock_t done_lock;
612 wait_queue_head_t done_wq;
614 unsigned int streaming:1;
615 unsigned int start_streaming_called:1;
616 unsigned int error:1;
617 unsigned int waiting_for_buffers:1;
618 unsigned int waiting_in_dqbuf:1;
619 unsigned int is_multiplanar:1;
620 unsigned int is_output:1;
621 unsigned int copy_timestamp:1;
622 unsigned int last_buffer_dequeued:1;
624 struct vb2_fileio_data *fileio;
625 struct vb2_threadio_data *threadio;
629 #ifdef CONFIG_VIDEO_ADV_DEBUG
631 * Counters for how often these queue-related ops are
632 * called. Used to check for unbalanced ops.
635 u32 cnt_wait_prepare;
637 u32 cnt_start_streaming;
638 u32 cnt_stop_streaming;
643 * vb2_queue_allows_cache_hints() - Return true if the queue allows cache
644 * and memory consistency hints.
646 * @q: pointer to &struct vb2_queue with videobuf2 queue
648 static inline bool vb2_queue_allows_cache_hints(struct vb2_queue *q)
650 return q->allow_cache_hints && q->memory == VB2_MEMORY_MMAP;
654 * vb2_plane_vaddr() - Return a kernel virtual address of a given plane.
655 * @vb: pointer to &struct vb2_buffer to which the plane in
656 * question belongs to.
657 * @plane_no: plane number for which the address is to be returned.
659 * This function returns a kernel virtual address of a given plane if
660 * such a mapping exist, NULL otherwise.
662 void *vb2_plane_vaddr(struct vb2_buffer *vb, unsigned int plane_no);
665 * vb2_plane_cookie() - Return allocator specific cookie for the given plane.
666 * @vb: pointer to &struct vb2_buffer to which the plane in
667 * question belongs to.
668 * @plane_no: plane number for which the cookie is to be returned.
670 * This function returns an allocator specific cookie for a given plane if
671 * available, NULL otherwise. The allocator should provide some simple static
672 * inline function, which would convert this cookie to the allocator specific
673 * type that can be used directly by the driver to access the buffer. This can
674 * be for example physical address, pointer to scatter list or IOMMU mapping.
676 void *vb2_plane_cookie(struct vb2_buffer *vb, unsigned int plane_no);
679 * vb2_buffer_done() - inform videobuf that an operation on a buffer
681 * @vb: pointer to &struct vb2_buffer to be used.
682 * @state: state of the buffer, as defined by &enum vb2_buffer_state.
683 * Either %VB2_BUF_STATE_DONE if the operation finished
684 * successfully, %VB2_BUF_STATE_ERROR if the operation finished
685 * with an error or %VB2_BUF_STATE_QUEUED.
687 * This function should be called by the driver after a hardware operation on
688 * a buffer is finished and the buffer may be returned to userspace. The driver
689 * cannot use this buffer anymore until it is queued back to it by videobuf
690 * by the means of &vb2_ops->buf_queue callback. Only buffers previously queued
691 * to the driver by &vb2_ops->buf_queue can be passed to this function.
693 * While streaming a buffer can only be returned in state DONE or ERROR.
694 * The &vb2_ops->start_streaming op can also return them in case the DMA engine
695 * cannot be started for some reason. In that case the buffers should be
696 * returned with state QUEUED to put them back into the queue.
698 void vb2_buffer_done(struct vb2_buffer *vb, enum vb2_buffer_state state);
701 * vb2_discard_done() - discard all buffers marked as DONE.
702 * @q: pointer to &struct vb2_queue with videobuf2 queue.
704 * This function is intended to be used with suspend/resume operations. It
705 * discards all 'done' buffers as they would be too old to be requested after
708 * Drivers must stop the hardware and synchronize with interrupt handlers and/or
709 * delayed works before calling this function to make sure no buffer will be
710 * touched by the driver and/or hardware.
712 void vb2_discard_done(struct vb2_queue *q);
715 * vb2_wait_for_all_buffers() - wait until all buffers are given back to vb2.
716 * @q: pointer to &struct vb2_queue with videobuf2 queue.
718 * This function will wait until all buffers that have been given to the driver
719 * by &vb2_ops->buf_queue are given back to vb2 with vb2_buffer_done(). It
720 * doesn't call &vb2_ops->wait_prepare/&vb2_ops->wait_finish pair.
721 * It is intended to be called with all locks taken, for example from
722 * &vb2_ops->stop_streaming callback.
724 int vb2_wait_for_all_buffers(struct vb2_queue *q);
727 * vb2_core_querybuf() - query video buffer information.
728 * @q: pointer to &struct vb2_queue with videobuf2 queue.
729 * @index: id number of the buffer.
730 * @pb: buffer struct passed from userspace.
732 * Videobuf2 core helper to implement VIDIOC_QUERYBUF() operation. It is called
733 * internally by VB2 by an API-specific handler, like ``videobuf2-v4l2.h``.
735 * The passed buffer should have been verified.
737 * This function fills the relevant information for the userspace.
739 * Return: returns zero on success; an error code otherwise.
741 void vb2_core_querybuf(struct vb2_queue *q, unsigned int index, void *pb);
744 * vb2_core_reqbufs() - Initiate streaming.
745 * @q: pointer to &struct vb2_queue with videobuf2 queue.
746 * @memory: memory type, as defined by &enum vb2_memory.
747 * @count: requested buffer count.
749 * Videobuf2 core helper to implement VIDIOC_REQBUF() operation. It is called
750 * internally by VB2 by an API-specific handler, like ``videobuf2-v4l2.h``.
754 * #) verifies streaming parameters passed from the userspace;
755 * #) sets up the queue;
756 * #) negotiates number of buffers and planes per buffer with the driver
757 * to be used during streaming;
758 * #) allocates internal buffer structures (&struct vb2_buffer), according to
759 * the agreed parameters;
760 * #) for MMAP memory type, allocates actual video memory, using the
761 * memory handling/allocation routines provided during queue initialization.
763 * If req->count is 0, all the memory will be freed instead.
765 * If the queue has been allocated previously by a previous vb2_core_reqbufs()
766 * call and the queue is not busy, memory will be reallocated.
768 * Return: returns zero on success; an error code otherwise.
770 int vb2_core_reqbufs(struct vb2_queue *q, enum vb2_memory memory,
771 unsigned int *count);
774 * vb2_core_create_bufs() - Allocate buffers and any required auxiliary structs
775 * @q: pointer to &struct vb2_queue with videobuf2 queue.
776 * @memory: memory type, as defined by &enum vb2_memory.
777 * @count: requested buffer count.
778 * @requested_planes: number of planes requested.
779 * @requested_sizes: array with the size of the planes.
781 * Videobuf2 core helper to implement VIDIOC_CREATE_BUFS() operation. It is
782 * called internally by VB2 by an API-specific handler, like
783 * ``videobuf2-v4l2.h``.
787 * #) verifies parameter sanity;
788 * #) calls the &vb2_ops->queue_setup queue operation;
789 * #) performs any necessary memory allocations.
791 * Return: returns zero on success; an error code otherwise.
793 int vb2_core_create_bufs(struct vb2_queue *q, enum vb2_memory memory,
795 unsigned int requested_planes,
796 const unsigned int requested_sizes[]);
799 * vb2_core_prepare_buf() - Pass ownership of a buffer from userspace
801 * @q: pointer to &struct vb2_queue with videobuf2 queue.
802 * @index: id number of the buffer.
803 * @pb: buffer structure passed from userspace to
804 * &v4l2_ioctl_ops->vidioc_prepare_buf handler in driver.
806 * Videobuf2 core helper to implement VIDIOC_PREPARE_BUF() operation. It is
807 * called internally by VB2 by an API-specific handler, like
808 * ``videobuf2-v4l2.h``.
810 * The passed buffer should have been verified.
812 * This function calls vb2_ops->buf_prepare callback in the driver
813 * (if provided), in which driver-specific buffer initialization can
816 * Return: returns zero on success; an error code otherwise.
818 int vb2_core_prepare_buf(struct vb2_queue *q, unsigned int index, void *pb);
821 * vb2_core_qbuf() - Queue a buffer from userspace
823 * @q: pointer to &struct vb2_queue with videobuf2 queue.
824 * @index: id number of the buffer
825 * @pb: buffer structure passed from userspace to
826 * v4l2_ioctl_ops->vidioc_qbuf handler in driver
827 * @req: pointer to &struct media_request, may be NULL.
829 * Videobuf2 core helper to implement VIDIOC_QBUF() operation. It is called
830 * internally by VB2 by an API-specific handler, like ``videobuf2-v4l2.h``.
834 * #) If @req is non-NULL, then the buffer will be bound to this
835 * media request and it returns. The buffer will be prepared and
836 * queued to the driver (i.e. the next two steps) when the request
838 * #) if necessary, calls &vb2_ops->buf_prepare callback in the driver
839 * (if provided), in which driver-specific buffer initialization can
841 * #) if streaming is on, queues the buffer in driver by the means of
842 * &vb2_ops->buf_queue callback for processing.
844 * Return: returns zero on success; an error code otherwise.
846 int vb2_core_qbuf(struct vb2_queue *q, unsigned int index, void *pb,
847 struct media_request *req);
850 * vb2_core_dqbuf() - Dequeue a buffer to the userspace
851 * @q: pointer to &struct vb2_queue with videobuf2 queue
852 * @pindex: pointer to the buffer index. May be NULL
853 * @pb: buffer structure passed from userspace to
854 * v4l2_ioctl_ops->vidioc_dqbuf handler in driver.
855 * @nonblocking: if true, this call will not sleep waiting for a buffer if no
856 * buffers ready for dequeuing are present. Normally the driver
857 * would be passing (file->f_flags & O_NONBLOCK) here.
859 * Videobuf2 core helper to implement VIDIOC_DQBUF() operation. It is called
860 * internally by VB2 by an API-specific handler, like ``videobuf2-v4l2.h``.
864 * #) calls buf_finish callback in the driver (if provided), in which
865 * driver can perform any additional operations that may be required before
866 * returning the buffer to userspace, such as cache sync,
867 * #) the buffer struct members are filled with relevant information for
870 * Return: returns zero on success; an error code otherwise.
872 int vb2_core_dqbuf(struct vb2_queue *q, unsigned int *pindex, void *pb,
876 * vb2_core_streamon() - Implements VB2 stream ON logic
878 * @q: pointer to &struct vb2_queue with videobuf2 queue
879 * @type: type of the queue to be started.
880 * For V4L2, this is defined by &enum v4l2_buf_type type.
882 * Videobuf2 core helper to implement VIDIOC_STREAMON() operation. It is called
883 * internally by VB2 by an API-specific handler, like ``videobuf2-v4l2.h``.
885 * Return: returns zero on success; an error code otherwise.
887 int vb2_core_streamon(struct vb2_queue *q, unsigned int type);
890 * vb2_core_streamoff() - Implements VB2 stream OFF logic
892 * @q: pointer to &struct vb2_queue with videobuf2 queue
893 * @type: type of the queue to be started.
894 * For V4L2, this is defined by &enum v4l2_buf_type type.
896 * Videobuf2 core helper to implement VIDIOC_STREAMOFF() operation. It is
897 * called internally by VB2 by an API-specific handler, like
898 * ``videobuf2-v4l2.h``.
900 * Return: returns zero on success; an error code otherwise.
902 int vb2_core_streamoff(struct vb2_queue *q, unsigned int type);
905 * vb2_core_expbuf() - Export a buffer as a file descriptor.
906 * @q: pointer to &struct vb2_queue with videobuf2 queue.
907 * @fd: pointer to the file descriptor associated with DMABUF
909 * @type: buffer type.
910 * @index: id number of the buffer.
911 * @plane: index of the plane to be exported, 0 for single plane queues
912 * @flags: file flags for newly created file, as defined at
913 * include/uapi/asm-generic/fcntl.h.
914 * Currently, the only used flag is %O_CLOEXEC.
915 * is supported, refer to manual of open syscall for more details.
918 * Videobuf2 core helper to implement VIDIOC_EXPBUF() operation. It is called
919 * internally by VB2 by an API-specific handler, like ``videobuf2-v4l2.h``.
921 * Return: returns zero on success; an error code otherwise.
923 int vb2_core_expbuf(struct vb2_queue *q, int *fd, unsigned int type,
924 unsigned int index, unsigned int plane, unsigned int flags);
927 * vb2_core_queue_init() - initialize a videobuf2 queue
928 * @q: pointer to &struct vb2_queue with videobuf2 queue.
929 * This structure should be allocated in driver
931 * The &vb2_queue structure should be allocated by the driver. The driver is
932 * responsible of clearing it's content and setting initial values for some
933 * required entries before calling this function.
937 * The following fields at @q should be set before calling this function:
938 * &vb2_queue->ops, &vb2_queue->mem_ops, &vb2_queue->type.
940 int vb2_core_queue_init(struct vb2_queue *q);
943 * vb2_core_queue_release() - stop streaming, release the queue and free memory
944 * @q: pointer to &struct vb2_queue with videobuf2 queue.
946 * This function stops streaming and performs necessary clean ups, including
947 * freeing video buffer memory. The driver is responsible for freeing
948 * the &struct vb2_queue itself.
950 void vb2_core_queue_release(struct vb2_queue *q);
953 * vb2_queue_error() - signal a fatal error on the queue
954 * @q: pointer to &struct vb2_queue with videobuf2 queue.
956 * Flag that a fatal unrecoverable error has occurred and wake up all processes
957 * waiting on the queue. Polling will now set %EPOLLERR and queuing and dequeuing
958 * buffers will return %-EIO.
960 * The error flag will be cleared when canceling the queue, either from
961 * vb2_streamoff() or vb2_queue_release(). Drivers should thus not call this
962 * function before starting the stream, otherwise the error flag will remain set
963 * until the queue is released when closing the device node.
965 void vb2_queue_error(struct vb2_queue *q);
968 * vb2_mmap() - map video buffers into application address space.
969 * @q: pointer to &struct vb2_queue with videobuf2 queue.
970 * @vma: pointer to &struct vm_area_struct with the vma passed
971 * to the mmap file operation handler in the driver.
973 * Should be called from mmap file operation handler of a driver.
974 * This function maps one plane of one of the available video buffers to
975 * userspace. To map whole video memory allocated on reqbufs, this function
976 * has to be called once per each plane per each buffer previously allocated.
978 * When the userspace application calls mmap, it passes to it an offset returned
979 * to it earlier by the means of &v4l2_ioctl_ops->vidioc_querybuf handler.
980 * That offset acts as a "cookie", which is then used to identify the plane
983 * This function finds a plane with a matching offset and a mapping is performed
984 * by the means of a provided memory operation.
986 * The return values from this function are intended to be directly returned
987 * from the mmap handler in driver.
989 int vb2_mmap(struct vb2_queue *q, struct vm_area_struct *vma);
993 * vb2_get_unmapped_area - map video buffers into application address space.
994 * @q: pointer to &struct vb2_queue with videobuf2 queue.
995 * @addr: memory address.
997 * @pgoff: page offset.
998 * @flags: memory flags.
1000 * This function is used in noMMU platforms to propose address mapping
1001 * for a given buffer. It's intended to be used as a handler for the
1002 * &file_operations->get_unmapped_area operation.
1004 * This is called by the mmap() syscall routines will call this
1005 * to get a proposed address for the mapping, when ``!CONFIG_MMU``.
1007 unsigned long vb2_get_unmapped_area(struct vb2_queue *q,
1010 unsigned long pgoff,
1011 unsigned long flags);
1015 * vb2_core_poll() - implements poll syscall() logic.
1016 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1017 * @file: &struct file argument passed to the poll
1018 * file operation handler.
1019 * @wait: &poll_table wait argument passed to the poll
1020 * file operation handler.
1022 * This function implements poll file operation handler for a driver.
1023 * For CAPTURE queues, if a buffer is ready to be dequeued, the userspace will
1024 * be informed that the file descriptor of a video device is available for
1026 * For OUTPUT queues, if a buffer is ready to be dequeued, the file descriptor
1027 * will be reported as available for writing.
1029 * The return values from this function are intended to be directly returned
1030 * from poll handler in driver.
1032 __poll_t vb2_core_poll(struct vb2_queue *q, struct file *file,
1036 * vb2_read() - implements read() syscall logic.
1037 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1038 * @data: pointed to target userspace buffer
1039 * @count: number of bytes to read
1040 * @ppos: file handle position tracking pointer
1041 * @nonblock: mode selector (1 means blocking calls, 0 means nonblocking)
1043 size_t vb2_read(struct vb2_queue *q, char __user *data, size_t count,
1044 loff_t *ppos, int nonblock);
1046 * vb2_read() - implements write() syscall logic.
1047 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1048 * @data: pointed to target userspace buffer
1049 * @count: number of bytes to write
1050 * @ppos: file handle position tracking pointer
1051 * @nonblock: mode selector (1 means blocking calls, 0 means nonblocking)
1053 size_t vb2_write(struct vb2_queue *q, const char __user *data, size_t count,
1054 loff_t *ppos, int nonblock);
1057 * typedef vb2_thread_fnc - callback function for use with vb2_thread.
1059 * @vb: pointer to struct &vb2_buffer.
1060 * @priv: pointer to a private data.
1062 * This is called whenever a buffer is dequeued in the thread.
1064 typedef int (*vb2_thread_fnc)(struct vb2_buffer *vb, void *priv);
1067 * vb2_thread_start() - start a thread for the given queue.
1068 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1069 * @fnc: &vb2_thread_fnc callback function.
1070 * @priv: priv pointer passed to the callback function.
1071 * @thread_name:the name of the thread. This will be prefixed with "vb2-".
1073 * This starts a thread that will queue and dequeue until an error occurs
1074 * or vb2_thread_stop() is called.
1078 * This function should not be used for anything else but the videobuf2-dvb
1079 * support. If you think you have another good use-case for this, then please
1080 * contact the linux-media mailing list first.
1082 int vb2_thread_start(struct vb2_queue *q, vb2_thread_fnc fnc, void *priv,
1083 const char *thread_name);
1086 * vb2_thread_stop() - stop the thread for the given queue.
1087 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1089 int vb2_thread_stop(struct vb2_queue *q);
1092 * vb2_is_streaming() - return streaming status of the queue.
1093 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1095 static inline bool vb2_is_streaming(struct vb2_queue *q)
1097 return q->streaming;
1101 * vb2_fileio_is_active() - return true if fileio is active.
1102 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1104 * This returns true if read() or write() is used to stream the data
1105 * as opposed to stream I/O. This is almost never an important distinction,
1106 * except in rare cases. One such case is that using read() or write() to
1107 * stream a format using %V4L2_FIELD_ALTERNATE is not allowed since there
1108 * is no way you can pass the field information of each buffer to/from
1109 * userspace. A driver that supports this field format should check for
1110 * this in the &vb2_ops->queue_setup op and reject it if this function returns
1113 static inline bool vb2_fileio_is_active(struct vb2_queue *q)
1119 * vb2_is_busy() - return busy status of the queue.
1120 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1122 * This function checks if queue has any buffers allocated.
1124 static inline bool vb2_is_busy(struct vb2_queue *q)
1126 return (q->num_buffers > 0);
1130 * vb2_get_drv_priv() - return driver private data associated with the queue.
1131 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1133 static inline void *vb2_get_drv_priv(struct vb2_queue *q)
1139 * vb2_set_plane_payload() - set bytesused for the plane @plane_no.
1140 * @vb: pointer to &struct vb2_buffer to which the plane in
1141 * question belongs to.
1142 * @plane_no: plane number for which payload should be set.
1143 * @size: payload in bytes.
1145 static inline void vb2_set_plane_payload(struct vb2_buffer *vb,
1146 unsigned int plane_no, unsigned long size)
1148 if (plane_no < vb->num_planes)
1149 vb->planes[plane_no].bytesused = size;
1153 * vb2_get_plane_payload() - get bytesused for the plane plane_no
1154 * @vb: pointer to &struct vb2_buffer to which the plane in
1155 * question belongs to.
1156 * @plane_no: plane number for which payload should be set.
1158 static inline unsigned long vb2_get_plane_payload(struct vb2_buffer *vb,
1159 unsigned int plane_no)
1161 if (plane_no < vb->num_planes)
1162 return vb->planes[plane_no].bytesused;
1167 * vb2_plane_size() - return plane size in bytes.
1168 * @vb: pointer to &struct vb2_buffer to which the plane in
1169 * question belongs to.
1170 * @plane_no: plane number for which size should be returned.
1172 static inline unsigned long
1173 vb2_plane_size(struct vb2_buffer *vb, unsigned int plane_no)
1175 if (plane_no < vb->num_planes)
1176 return vb->planes[plane_no].length;
1181 * vb2_start_streaming_called() - return streaming status of driver.
1182 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1184 static inline bool vb2_start_streaming_called(struct vb2_queue *q)
1186 return q->start_streaming_called;
1190 * vb2_clear_last_buffer_dequeued() - clear last buffer dequeued flag of queue.
1191 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1193 static inline void vb2_clear_last_buffer_dequeued(struct vb2_queue *q)
1195 q->last_buffer_dequeued = false;
1199 * vb2_get_buffer() - get a buffer from a queue
1200 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1201 * @index: buffer index
1203 * This function obtains a buffer from a queue, by its index.
1204 * Keep in mind that there is no refcounting involved in this
1205 * operation, so the buffer lifetime should be taken into
1208 static inline struct vb2_buffer *vb2_get_buffer(struct vb2_queue *q,
1211 if (index < q->num_buffers)
1212 return q->bufs[index];
1217 * The following functions are not part of the vb2 core API, but are useful
1218 * functions for videobuf2-*.
1222 * vb2_buffer_in_use() - return true if the buffer is in use and
1223 * the queue cannot be freed (by the means of VIDIOC_REQBUFS(0)) call.
1225 * @vb: buffer for which plane size should be returned.
1226 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1228 bool vb2_buffer_in_use(struct vb2_queue *q, struct vb2_buffer *vb);
1231 * vb2_verify_memory_type() - Check whether the memory type and buffer type
1232 * passed to a buffer operation are compatible with the queue.
1234 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1235 * @memory: memory model, as defined by enum &vb2_memory.
1236 * @type: private buffer type whose content is defined by the vb2-core
1237 * caller. For example, for V4L2, it should match
1238 * the types defined on enum &v4l2_buf_type.
1240 int vb2_verify_memory_type(struct vb2_queue *q,
1241 enum vb2_memory memory, unsigned int type);
1244 * vb2_request_object_is_buffer() - return true if the object is a buffer
1246 * @obj: the request object.
1248 bool vb2_request_object_is_buffer(struct media_request_object *obj);
1251 * vb2_request_buffer_cnt() - return the number of buffers in the request
1253 * @req: the request.
1255 unsigned int vb2_request_buffer_cnt(struct media_request *req);
1257 #endif /* _MEDIA_VIDEOBUF2_CORE_H */