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.
58 * @put: inform the allocator that the buffer will no longer be used;
59 * usually will result in the allocator freeing the buffer (if
60 * no other users of this buffer are present); the @buf_priv
61 * argument is the allocator private per-buffer structure
62 * previously returned from the alloc callback.
63 * @get_dmabuf: acquire userspace memory for a hardware operation; used for
64 * DMABUF memory types.
65 * @get_userptr: acquire userspace memory for a hardware operation; used for
66 * USERPTR memory types; vaddr is the address passed to the
67 * videobuf layer when queuing a video buffer of USERPTR type;
68 * should return an allocator private per-buffer structure
69 * associated with the buffer on success, ERR_PTR() on failure;
70 * the returned private structure will then be passed as @buf_priv
71 * argument to other ops in this structure.
72 * @put_userptr: inform the allocator that a USERPTR buffer will no longer
74 * @attach_dmabuf: attach a shared &struct dma_buf for a hardware operation;
75 * used for DMABUF memory types; dev is the alloc device
76 * dbuf is the shared dma_buf; returns ERR_PTR() on failure;
77 * allocator private per-buffer structure on success;
78 * this needs to be used for further accesses to the buffer.
79 * @detach_dmabuf: inform the exporter of the buffer that the current DMABUF
80 * buffer is no longer used; the @buf_priv argument is the
81 * allocator private per-buffer structure previously returned
82 * from the attach_dmabuf callback.
83 * @map_dmabuf: request for access to the dmabuf from allocator; the allocator
84 * of dmabuf is informed that this driver is going to use the
86 * @unmap_dmabuf: releases access control to the dmabuf - allocator is notified
87 * that this driver is done using the dmabuf for now.
88 * @prepare: called every time the buffer is passed from userspace to the
89 * driver, useful for cache synchronisation, optional.
90 * @finish: called every time the buffer is passed back from the driver
91 * to the userspace, also optional.
92 * @vaddr: return a kernel virtual address to a given memory buffer
93 * associated with the passed private structure or NULL if no
94 * such mapping exists.
95 * @cookie: return allocator specific cookie for a given memory buffer
96 * associated with the passed private structure or NULL if not
98 * @num_users: return the current number of users of a memory buffer;
99 * return 1 if the videobuf layer (or actually the driver using
100 * it) is the only user.
101 * @mmap: setup a userspace mapping for a given memory buffer under
102 * the provided virtual memory region.
104 * Those operations are used by the videobuf2 core to implement the memory
105 * handling/memory allocators for each type of supported streaming I/O method.
108 * #) Required ops for USERPTR types: get_userptr, put_userptr.
110 * #) Required ops for MMAP types: alloc, put, num_users, mmap.
112 * #) Required ops for read/write access types: alloc, put, num_users, vaddr.
114 * #) Required ops for DMABUF types: attach_dmabuf, detach_dmabuf,
115 * map_dmabuf, unmap_dmabuf.
118 void *(*alloc
)(struct device
*dev
, unsigned long attrs
,
120 enum dma_data_direction dma_dir
,
122 void (*put
)(void *buf_priv
);
123 struct dma_buf
*(*get_dmabuf
)(void *buf_priv
, unsigned long flags
);
125 void *(*get_userptr
)(struct device
*dev
, unsigned long vaddr
,
127 enum dma_data_direction dma_dir
);
128 void (*put_userptr
)(void *buf_priv
);
130 void (*prepare
)(void *buf_priv
);
131 void (*finish
)(void *buf_priv
);
133 void *(*attach_dmabuf
)(struct device
*dev
,
134 struct dma_buf
*dbuf
,
136 enum dma_data_direction dma_dir
);
137 void (*detach_dmabuf
)(void *buf_priv
);
138 int (*map_dmabuf
)(void *buf_priv
);
139 void (*unmap_dmabuf
)(void *buf_priv
);
141 void *(*vaddr
)(void *buf_priv
);
142 void *(*cookie
)(void *buf_priv
);
144 unsigned int (*num_users
)(void *buf_priv
);
146 int (*mmap
)(void *buf_priv
, struct vm_area_struct
*vma
);
150 * struct vb2_plane - plane information.
151 * @mem_priv: private data with this plane.
152 * @dbuf: dma_buf - shared buffer object.
153 * @dbuf_mapped: flag to show whether dbuf is mapped or not
154 * @bytesused: number of bytes occupied by data in the plane (payload).
155 * @length: size of this plane (NOT the payload) in bytes.
156 * @min_length: minimum required size of this plane (NOT the payload) in bytes.
157 * @length is always greater or equal to @min_length.
158 * @m: Union with memtype-specific data.
159 * @m.offset: when memory in the associated struct vb2_buffer is
160 * %VB2_MEMORY_MMAP, equals the offset from the start of
161 * the device memory for this plane (or is a "cookie" that
162 * should be passed to mmap() called on the video node).
163 * @m.userptr: when memory is %VB2_MEMORY_USERPTR, a userspace pointer
164 * pointing to this plane.
165 * @m.fd: when memory is %VB2_MEMORY_DMABUF, a userspace file
166 * descriptor associated with this plane.
167 * @data_offset: offset in the plane to the start of data; usually 0,
168 * unless there is a header in front of the data.
170 * Should contain enough information to be able to cover all the fields
171 * of &struct v4l2_plane at videodev2.h.
175 struct dma_buf
*dbuf
;
176 unsigned int dbuf_mapped
;
177 unsigned int bytesused
;
179 unsigned int min_length
;
182 unsigned long userptr
;
185 unsigned int data_offset
;
189 * enum vb2_io_modes - queue access methods.
190 * @VB2_MMAP: driver supports MMAP with streaming API.
191 * @VB2_USERPTR: driver supports USERPTR with streaming API.
192 * @VB2_READ: driver supports read() style access.
193 * @VB2_WRITE: driver supports write() style access.
194 * @VB2_DMABUF: driver supports DMABUF with streaming API.
198 VB2_USERPTR
= BIT(1),
205 * enum vb2_buffer_state - current video buffer state.
206 * @VB2_BUF_STATE_DEQUEUED: buffer under userspace control.
207 * @VB2_BUF_STATE_IN_REQUEST: buffer is queued in media request.
208 * @VB2_BUF_STATE_PREPARING: buffer is being prepared in videobuf.
209 * @VB2_BUF_STATE_QUEUED: buffer queued in videobuf, but not in driver.
210 * @VB2_BUF_STATE_REQUEUEING: re-queue a buffer to the 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_REQUEUEING
,
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 * @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_object req_obj
;
254 /* private: internal use only
256 * state: current buffer state; do not change
257 * synced: this buffer has been synced for DMA, i.e. the
258 * 'prepare' memop was called. It is cleared again
259 * after the 'finish' memop is called.
260 * prepared: this buffer has been prepared, i.e. the
261 * buf_prepare op was called. It is cleared again
262 * after the 'buf_finish' op is called.
263 * queued_entry: entry on the queued buffers list, which holds
264 * all buffers queued from userspace
265 * done_entry: entry on the list that stores all buffers ready
266 * to be dequeued to userspace
267 * vb2_plane: per-plane information; do not change
269 enum vb2_buffer_state state
;
273 struct vb2_plane planes
[VB2_MAX_PLANES
];
274 struct list_head queued_entry
;
275 struct list_head done_entry
;
276 #ifdef CONFIG_VIDEO_ADV_DEBUG
278 * Counters for how often these buffer-related ops are
279 * called. Used to check for unbalanced ops.
283 u32 cnt_mem_get_dmabuf
;
284 u32 cnt_mem_get_userptr
;
285 u32 cnt_mem_put_userptr
;
288 u32 cnt_mem_attach_dmabuf
;
289 u32 cnt_mem_detach_dmabuf
;
290 u32 cnt_mem_map_dmabuf
;
291 u32 cnt_mem_unmap_dmabuf
;
294 u32 cnt_mem_num_users
;
302 u32 cnt_buf_request_complete
;
304 /* This counts the number of calls to vb2_buffer_done() */
310 * struct vb2_ops - driver-specific callbacks.
312 * These operations are not called from interrupt context except where
313 * mentioned specifically.
315 * @queue_setup: called from VIDIOC_REQBUFS() and VIDIOC_CREATE_BUFS()
316 * handlers before memory allocation. It can be called
317 * twice: if the original number of requested buffers
318 * could not be allocated, then it will be called a
319 * second time with the actually allocated number of
320 * buffers to verify if that is OK.
321 * The driver should return the required number of buffers
322 * in \*num_buffers, the required number of planes per
323 * buffer in \*num_planes, the size of each plane should be
324 * set in the sizes\[\] array and optional per-plane
325 * allocator specific device in the alloc_devs\[\] array.
326 * When called from VIDIOC_REQBUFS(), \*num_planes == 0,
327 * the driver has to use the currently configured format to
328 * determine the plane sizes and \*num_buffers is the total
329 * number of buffers that are being allocated. When called
330 * from VIDIOC_CREATE_BUFS(), \*num_planes != 0 and it
331 * describes the requested number of planes and sizes\[\]
332 * contains the requested plane sizes. In this case
333 * \*num_buffers are being allocated additionally to
334 * q->num_buffers. If either \*num_planes or the requested
335 * sizes are invalid callback must return %-EINVAL.
336 * @wait_prepare: release any locks taken while calling vb2 functions;
337 * it is called before an ioctl needs to wait for a new
338 * buffer to arrive; required to avoid a deadlock in
339 * blocking access type.
340 * @wait_finish: reacquire all locks released in the previous callback;
341 * required to continue operation after sleeping while
342 * waiting for a new buffer to arrive.
343 * @buf_init: called once after allocating a buffer (in MMAP case)
344 * or after acquiring a new USERPTR buffer; drivers may
345 * perform additional buffer-related initialization;
346 * initialization failure (return != 0) will prevent
347 * queue setup from completing successfully; optional.
348 * @buf_prepare: called every time the buffer is queued from userspace
349 * and from the VIDIOC_PREPARE_BUF() ioctl; drivers may
350 * perform any initialization required before each
351 * hardware operation in this callback; drivers can
352 * access/modify the buffer here as it is still synced for
353 * the CPU; drivers that support VIDIOC_CREATE_BUFS() must
354 * also validate the buffer size; if an error is returned,
355 * the buffer will not be queued in driver; optional.
356 * @buf_finish: called before every dequeue of the buffer back to
357 * userspace; the buffer is synced for the CPU, so drivers
358 * can access/modify the buffer contents; drivers may
359 * perform any operations required before userspace
360 * accesses the buffer; optional. The buffer state can be
361 * one of the following: %DONE and %ERROR occur while
362 * streaming is in progress, and the %PREPARED state occurs
363 * when the queue has been canceled and all pending
364 * buffers are being returned to their default %DEQUEUED
365 * state. Typically you only have to do something if the
366 * state is %VB2_BUF_STATE_DONE, since in all other cases
367 * the buffer contents will be ignored anyway.
368 * @buf_cleanup: called once before the buffer is freed; drivers may
369 * perform any additional cleanup; optional.
370 * @start_streaming: called once to enter 'streaming' state; the driver may
371 * receive buffers with @buf_queue callback
372 * before @start_streaming is called; the driver gets the
373 * number of already queued buffers in count parameter;
374 * driver can return an error if hardware fails, in that
375 * case all buffers that have been already given by
376 * the @buf_queue callback are to be returned by the driver
377 * by calling vb2_buffer_done() with %VB2_BUF_STATE_QUEUED
378 * or %VB2_BUF_STATE_REQUEUEING. If you need a minimum
379 * number of buffers before you can start streaming, then
380 * set &vb2_queue->min_buffers_needed. If that is non-zero
381 * then @start_streaming won't be called until at least
382 * that many buffers have been queued up by userspace.
383 * @stop_streaming: called when 'streaming' state must be disabled; driver
384 * should stop any DMA transactions or wait until they
385 * finish and give back all buffers it got from &buf_queue
386 * callback by calling vb2_buffer_done() with either
387 * %VB2_BUF_STATE_DONE or %VB2_BUF_STATE_ERROR; may use
388 * vb2_wait_for_all_buffers() function
389 * @buf_queue: passes buffer vb to the driver; driver may start
390 * hardware operation on this buffer; driver should give
391 * the buffer back by calling vb2_buffer_done() function;
392 * it is allways called after calling VIDIOC_STREAMON()
393 * ioctl; might be called before @start_streaming callback
394 * if user pre-queued buffers before calling
396 * @buf_request_complete: a buffer that was never queued to the driver but is
397 * associated with a queued request was canceled.
398 * The driver will have to mark associated objects in the
399 * request as completed; required if requests are
403 int (*queue_setup
)(struct vb2_queue
*q
,
404 unsigned int *num_buffers
, unsigned int *num_planes
,
405 unsigned int sizes
[], struct device
*alloc_devs
[]);
407 void (*wait_prepare
)(struct vb2_queue
*q
);
408 void (*wait_finish
)(struct vb2_queue
*q
);
410 int (*buf_init
)(struct vb2_buffer
*vb
);
411 int (*buf_prepare
)(struct vb2_buffer
*vb
);
412 void (*buf_finish
)(struct vb2_buffer
*vb
);
413 void (*buf_cleanup
)(struct vb2_buffer
*vb
);
415 int (*start_streaming
)(struct vb2_queue
*q
, unsigned int count
);
416 void (*stop_streaming
)(struct vb2_queue
*q
);
418 void (*buf_queue
)(struct vb2_buffer
*vb
);
420 void (*buf_request_complete
)(struct vb2_buffer
*vb
);
424 * struct vb2_buf_ops - driver-specific callbacks.
426 * @verify_planes_array: Verify that a given user space structure contains
427 * enough planes for the buffer. This is called
428 * for each dequeued buffer.
429 * @init_buffer: given a &vb2_buffer initialize the extra data after
431 * For V4L2 this is a &struct vb2_v4l2_buffer.
432 * @fill_user_buffer: given a &vb2_buffer fill in the userspace structure.
433 * For V4L2 this is a &struct v4l2_buffer.
434 * @fill_vb2_buffer: given a userspace structure, fill in the &vb2_buffer.
435 * If the userspace structure is invalid, then this op
436 * will return an error.
437 * @copy_timestamp: copy the timestamp from a userspace structure to
438 * the &struct vb2_buffer.
441 int (*verify_planes_array
)(struct vb2_buffer
*vb
, const void *pb
);
442 void (*init_buffer
)(struct vb2_buffer
*vb
);
443 void (*fill_user_buffer
)(struct vb2_buffer
*vb
, void *pb
);
444 int (*fill_vb2_buffer
)(struct vb2_buffer
*vb
, struct vb2_plane
*planes
);
445 void (*copy_timestamp
)(struct vb2_buffer
*vb
, const void *pb
);
449 * struct vb2_queue - a videobuf queue.
451 * @type: private buffer type whose content is defined by the vb2-core
452 * caller. For example, for V4L2, it should match
453 * the types defined on &enum v4l2_buf_type.
454 * @io_modes: supported io methods (see &enum vb2_io_modes).
455 * @alloc_devs: &struct device memory type/allocator-specific per-plane device
456 * @dev: device to use for the default allocation context if the driver
457 * doesn't fill in the @alloc_devs array.
458 * @dma_attrs: DMA attributes to use for the DMA.
459 * @bidirectional: when this flag is set the DMA direction for the buffers of
460 * this queue will be overridden with %DMA_BIDIRECTIONAL direction.
461 * This is useful in cases where the hardware (firmware) writes to
462 * a buffer which is mapped as read (%DMA_TO_DEVICE), or reads from
463 * buffer which is mapped for write (%DMA_FROM_DEVICE) in order
464 * to satisfy some internal hardware restrictions or adds a padding
465 * needed by the processing algorithm. In case the DMA mapping is
466 * not bidirectional but the hardware (firmware) trying to access
467 * the buffer (in the opposite direction) this could lead to an
468 * IOMMU protection faults.
469 * @fileio_read_once: report EOF after reading the first buffer
470 * @fileio_write_immediately: queue buffer after each write() call
471 * @allow_zero_bytesused: allow bytesused == 0 to be passed to the driver
472 * @quirk_poll_must_check_waiting_for_buffers: Return %EPOLLERR at poll when QBUF
473 * has not been called. This is a vb1 idiom that has been adopted
475 * @supports_requests: this queue supports the Request API.
476 * @uses_qbuf: qbuf was used directly for this queue. Set to 1 the first
477 * time this is called. Set to 0 when the queue is canceled.
478 * If this is 1, then you cannot queue buffers from a request.
479 * @uses_requests: requests are used for this queue. Set to 1 the first time
480 * a request is queued. Set to 0 when the queue is canceled.
481 * If this is 1, then you cannot queue buffers directly.
482 * @lock: pointer to a mutex that protects the &struct vb2_queue. The
483 * driver can set this to a mutex to let the v4l2 core serialize
484 * the queuing ioctls. If the driver wants to handle locking
485 * itself, then this should be set to NULL. This lock is not used
486 * by the videobuf2 core API.
487 * @owner: The filehandle that 'owns' the buffers, i.e. the filehandle
488 * that called reqbufs, create_buffers or started fileio.
489 * This field is not used by the videobuf2 core API, but it allows
490 * drivers to easily associate an owner filehandle with the queue.
491 * @ops: driver-specific callbacks
492 * @mem_ops: memory allocator specific callbacks
493 * @buf_ops: callbacks to deliver buffer information.
494 * between user-space and kernel-space.
495 * @drv_priv: driver private data.
496 * @buf_struct_size: size of the driver-specific buffer structure;
497 * "0" indicates the driver doesn't want to use a custom buffer
498 * structure type. for example, ``sizeof(struct vb2_v4l2_buffer)``
499 * will be used for v4l2.
500 * @timestamp_flags: Timestamp flags; ``V4L2_BUF_FLAG_TIMESTAMP_*`` and
501 * ``V4L2_BUF_FLAG_TSTAMP_SRC_*``
502 * @gfp_flags: additional gfp flags used when allocating the buffers.
503 * Typically this is 0, but it may be e.g. %GFP_DMA or %__GFP_DMA32
504 * to force the buffer allocation to a specific memory zone.
505 * @min_buffers_needed: the minimum number of buffers needed before
506 * @start_streaming can be called. Used when a DMA engine
507 * cannot be started unless at least this number of buffers
508 * have been queued into the driver.
511 * Private elements (won't appear at the uAPI book):
512 * @mmap_lock: private mutex used when buffers are allocated/freed/mmapped
513 * @memory: current memory type used
514 * @dma_dir: DMA mapping direction.
515 * @bufs: videobuf buffer structures
516 * @num_buffers: number of allocated/used buffers
517 * @queued_list: list of buffers currently queued from userspace
518 * @queued_count: number of buffers queued and ready for streaming.
519 * @owned_by_drv_count: number of buffers owned by the driver
520 * @done_list: list of buffers ready to be dequeued to userspace
521 * @done_lock: lock to protect done_list list
522 * @done_wq: waitqueue for processes waiting for buffers ready to be dequeued
523 * @streaming: current streaming state
524 * @start_streaming_called: @start_streaming was called successfully and we
526 * @error: a fatal error occurred on the queue
527 * @waiting_for_buffers: used in poll() to check if vb2 is still waiting for
528 * buffers. Only set for capture queues if qbuf has not yet been
529 * called since poll() needs to return %EPOLLERR in that situation.
530 * @is_multiplanar: set if buffer type is multiplanar
531 * @is_output: set if buffer type is output
532 * @copy_timestamp: set if vb2-core should set timestamps
533 * @last_buffer_dequeued: used in poll() and DQBUF to immediately return if the
534 * last decoded buffer was already dequeued. Set for capture queues
535 * when a buffer with the %V4L2_BUF_FLAG_LAST is dequeued.
536 * @fileio: file io emulator internal data, used only if emulator is active
537 * @threadio: thread io internal data, used only if thread is active
541 unsigned int io_modes
;
543 unsigned long dma_attrs
;
544 unsigned bidirectional
:1;
545 unsigned fileio_read_once
:1;
546 unsigned fileio_write_immediately
:1;
547 unsigned allow_zero_bytesused
:1;
548 unsigned quirk_poll_must_check_waiting_for_buffers
:1;
549 unsigned supports_requests
:1;
550 unsigned uses_qbuf
:1;
551 unsigned uses_requests
:1;
556 const struct vb2_ops
*ops
;
557 const struct vb2_mem_ops
*mem_ops
;
558 const struct vb2_buf_ops
*buf_ops
;
561 unsigned int buf_struct_size
;
564 u32 min_buffers_needed
;
566 struct device
*alloc_devs
[VB2_MAX_PLANES
];
568 /* private: internal use only */
569 struct mutex mmap_lock
;
571 enum dma_data_direction dma_dir
;
572 struct vb2_buffer
*bufs
[VB2_MAX_FRAME
];
573 unsigned int num_buffers
;
575 struct list_head queued_list
;
576 unsigned int queued_count
;
578 atomic_t owned_by_drv_count
;
579 struct list_head done_list
;
580 spinlock_t done_lock
;
581 wait_queue_head_t done_wq
;
583 unsigned int streaming
:1;
584 unsigned int start_streaming_called
:1;
585 unsigned int error
:1;
586 unsigned int waiting_for_buffers
:1;
587 unsigned int is_multiplanar
:1;
588 unsigned int is_output
:1;
589 unsigned int copy_timestamp
:1;
590 unsigned int last_buffer_dequeued
:1;
592 struct vb2_fileio_data
*fileio
;
593 struct vb2_threadio_data
*threadio
;
595 #ifdef CONFIG_VIDEO_ADV_DEBUG
597 * Counters for how often these queue-related ops are
598 * called. Used to check for unbalanced ops.
601 u32 cnt_wait_prepare
;
603 u32 cnt_start_streaming
;
604 u32 cnt_stop_streaming
;
609 * vb2_plane_vaddr() - Return a kernel virtual address of a given plane.
610 * @vb: pointer to &struct vb2_buffer to which the plane in
611 * question belongs to.
612 * @plane_no: plane number for which the address is to be returned.
614 * This function returns a kernel virtual address of a given plane if
615 * such a mapping exist, NULL otherwise.
617 void *vb2_plane_vaddr(struct vb2_buffer
*vb
, unsigned int plane_no
);
620 * vb2_plane_cookie() - Return allocator specific cookie for the given plane.
621 * @vb: pointer to &struct vb2_buffer to which the plane in
622 * question belongs to.
623 * @plane_no: plane number for which the cookie is to be returned.
625 * This function returns an allocator specific cookie for a given plane if
626 * available, NULL otherwise. The allocator should provide some simple static
627 * inline function, which would convert this cookie to the allocator specific
628 * type that can be used directly by the driver to access the buffer. This can
629 * be for example physical address, pointer to scatter list or IOMMU mapping.
631 void *vb2_plane_cookie(struct vb2_buffer
*vb
, unsigned int plane_no
);
634 * vb2_buffer_done() - inform videobuf that an operation on a buffer
636 * @vb: pointer to &struct vb2_buffer to be used.
637 * @state: state of the buffer, as defined by &enum vb2_buffer_state.
638 * Either %VB2_BUF_STATE_DONE if the operation finished
639 * successfully, %VB2_BUF_STATE_ERROR if the operation finished
640 * with an error or any of %VB2_BUF_STATE_QUEUED or
641 * %VB2_BUF_STATE_REQUEUEING if the driver wants to
642 * requeue buffers (see below).
644 * This function should be called by the driver after a hardware operation on
645 * a buffer is finished and the buffer may be returned to userspace. The driver
646 * cannot use this buffer anymore until it is queued back to it by videobuf
647 * by the means of &vb2_ops->buf_queue callback. Only buffers previously queued
648 * to the driver by &vb2_ops->buf_queue can be passed to this function.
650 * While streaming a buffer can only be returned in state DONE or ERROR.
651 * The &vb2_ops->start_streaming op can also return them in case the DMA engine
652 * cannot be started for some reason. In that case the buffers should be
653 * returned with state QUEUED or REQUEUEING to put them back into the queue.
655 * %VB2_BUF_STATE_REQUEUEING is like %VB2_BUF_STATE_QUEUED, but it also calls
656 * &vb2_ops->buf_queue to queue buffers back to the driver. Note that calling
657 * vb2_buffer_done(..., VB2_BUF_STATE_REQUEUEING) from interrupt context will
658 * result in &vb2_ops->buf_queue being called in interrupt context as well.
660 void vb2_buffer_done(struct vb2_buffer
*vb
, enum vb2_buffer_state state
);
663 * vb2_discard_done() - discard all buffers marked as DONE.
664 * @q: pointer to &struct vb2_queue with videobuf2 queue.
666 * This function is intended to be used with suspend/resume operations. It
667 * discards all 'done' buffers as they would be too old to be requested after
670 * Drivers must stop the hardware and synchronize with interrupt handlers and/or
671 * delayed works before calling this function to make sure no buffer will be
672 * touched by the driver and/or hardware.
674 void vb2_discard_done(struct vb2_queue
*q
);
677 * vb2_wait_for_all_buffers() - wait until all buffers are given back to vb2.
678 * @q: pointer to &struct vb2_queue with videobuf2 queue.
680 * This function will wait until all buffers that have been given to the driver
681 * by &vb2_ops->buf_queue are given back to vb2 with vb2_buffer_done(). It
682 * doesn't call &vb2_ops->wait_prepare/&vb2_ops->wait_finish pair.
683 * It is intended to be called with all locks taken, for example from
684 * &vb2_ops->stop_streaming callback.
686 int vb2_wait_for_all_buffers(struct vb2_queue
*q
);
689 * vb2_core_querybuf() - query video buffer information.
690 * @q: pointer to &struct vb2_queue with videobuf2 queue.
691 * @index: id number of the buffer.
692 * @pb: buffer struct passed from userspace.
694 * Videobuf2 core helper to implement VIDIOC_QUERYBUF() operation. It is called
695 * internally by VB2 by an API-specific handler, like ``videobuf2-v4l2.h``.
697 * The passed buffer should have been verified.
699 * This function fills the relevant information for the userspace.
701 * Return: returns zero on success; an error code otherwise.
703 void vb2_core_querybuf(struct vb2_queue
*q
, unsigned int index
, void *pb
);
706 * vb2_core_reqbufs() - Initiate streaming.
707 * @q: pointer to &struct vb2_queue with videobuf2 queue.
708 * @memory: memory type, as defined by &enum vb2_memory.
709 * @count: requested buffer count.
711 * Videobuf2 core helper to implement VIDIOC_REQBUF() operation. It is called
712 * internally by VB2 by an API-specific handler, like ``videobuf2-v4l2.h``.
716 * #) verifies streaming parameters passed from the userspace;
717 * #) sets up the queue;
718 * #) negotiates number of buffers and planes per buffer with the driver
719 * to be used during streaming;
720 * #) allocates internal buffer structures (&struct vb2_buffer), according to
721 * the agreed parameters;
722 * #) for MMAP memory type, allocates actual video memory, using the
723 * memory handling/allocation routines provided during queue initialization.
725 * If req->count is 0, all the memory will be freed instead.
727 * If the queue has been allocated previously by a previous vb2_core_reqbufs()
728 * call and the queue is not busy, memory will be reallocated.
730 * Return: returns zero on success; an error code otherwise.
732 int vb2_core_reqbufs(struct vb2_queue
*q
, enum vb2_memory memory
,
733 unsigned int *count
);
736 * vb2_core_create_bufs() - Allocate buffers and any required auxiliary structs
737 * @q: pointer to &struct vb2_queue with videobuf2 queue.
738 * @memory: memory type, as defined by &enum vb2_memory.
739 * @count: requested buffer count.
740 * @requested_planes: number of planes requested.
741 * @requested_sizes: array with the size of the planes.
743 * Videobuf2 core helper to implement VIDIOC_CREATE_BUFS() operation. It is
744 * called internally by VB2 by an API-specific handler, like
745 * ``videobuf2-v4l2.h``.
749 * #) verifies parameter sanity;
750 * #) calls the &vb2_ops->queue_setup queue operation;
751 * #) performs any necessary memory allocations.
753 * Return: returns zero on success; an error code otherwise.
755 int vb2_core_create_bufs(struct vb2_queue
*q
, enum vb2_memory memory
,
756 unsigned int *count
, unsigned int requested_planes
,
757 const unsigned int requested_sizes
[]);
760 * vb2_core_prepare_buf() - Pass ownership of a buffer from userspace
762 * @q: pointer to &struct vb2_queue with videobuf2 queue.
763 * @index: id number of the buffer.
764 * @pb: buffer structure passed from userspace to
765 * &v4l2_ioctl_ops->vidioc_prepare_buf handler in driver.
767 * Videobuf2 core helper to implement VIDIOC_PREPARE_BUF() operation. It is
768 * called internally by VB2 by an API-specific handler, like
769 * ``videobuf2-v4l2.h``.
771 * The passed buffer should have been verified.
773 * This function calls vb2_ops->buf_prepare callback in the driver
774 * (if provided), in which driver-specific buffer initialization can
777 * Return: returns zero on success; an error code otherwise.
779 int vb2_core_prepare_buf(struct vb2_queue
*q
, unsigned int index
, void *pb
);
782 * vb2_core_qbuf() - Queue a buffer from userspace
784 * @q: pointer to &struct vb2_queue with videobuf2 queue.
785 * @index: id number of the buffer
786 * @pb: buffer structure passed from userspace to
787 * v4l2_ioctl_ops->vidioc_qbuf handler in driver
788 * @req: pointer to &struct media_request, may be NULL.
790 * Videobuf2 core helper to implement VIDIOC_QBUF() operation. It is called
791 * internally by VB2 by an API-specific handler, like ``videobuf2-v4l2.h``.
795 * #) If @req is non-NULL, then the buffer will be bound to this
796 * media request and it returns. The buffer will be prepared and
797 * queued to the driver (i.e. the next two steps) when the request
799 * #) if necessary, calls &vb2_ops->buf_prepare callback in the driver
800 * (if provided), in which driver-specific buffer initialization can
802 * #) if streaming is on, queues the buffer in driver by the means of
803 * &vb2_ops->buf_queue callback for processing.
805 * Return: returns zero on success; an error code otherwise.
807 int vb2_core_qbuf(struct vb2_queue
*q
, unsigned int index
, void *pb
,
808 struct media_request
*req
);
811 * vb2_core_dqbuf() - Dequeue a buffer to the userspace
812 * @q: pointer to &struct vb2_queue with videobuf2 queue
813 * @pindex: pointer to the buffer index. May be NULL
814 * @pb: buffer structure passed from userspace to
815 * v4l2_ioctl_ops->vidioc_dqbuf handler in driver.
816 * @nonblocking: if true, this call will not sleep waiting for a buffer if no
817 * buffers ready for dequeuing are present. Normally the driver
818 * would be passing (file->f_flags & O_NONBLOCK) here.
820 * Videobuf2 core helper to implement VIDIOC_DQBUF() operation. It is called
821 * internally by VB2 by an API-specific handler, like ``videobuf2-v4l2.h``.
825 * #) calls buf_finish callback in the driver (if provided), in which
826 * driver can perform any additional operations that may be required before
827 * returning the buffer to userspace, such as cache sync,
828 * #) the buffer struct members are filled with relevant information for
831 * Return: returns zero on success; an error code otherwise.
833 int vb2_core_dqbuf(struct vb2_queue
*q
, unsigned int *pindex
, void *pb
,
837 * vb2_core_streamon() - Implements VB2 stream ON logic
839 * @q: pointer to &struct vb2_queue with videobuf2 queue
840 * @type: type of the queue to be started.
841 * For V4L2, this is defined by &enum v4l2_buf_type type.
843 * Videobuf2 core helper to implement VIDIOC_STREAMON() operation. It is called
844 * internally by VB2 by an API-specific handler, like ``videobuf2-v4l2.h``.
846 * Return: returns zero on success; an error code otherwise.
848 int vb2_core_streamon(struct vb2_queue
*q
, unsigned int type
);
851 * vb2_core_streamoff() - Implements VB2 stream OFF logic
853 * @q: pointer to &struct vb2_queue with videobuf2 queue
854 * @type: type of the queue to be started.
855 * For V4L2, this is defined by &enum v4l2_buf_type type.
857 * Videobuf2 core helper to implement VIDIOC_STREAMOFF() operation. It is
858 * called internally by VB2 by an API-specific handler, like
859 * ``videobuf2-v4l2.h``.
861 * Return: returns zero on success; an error code otherwise.
863 int vb2_core_streamoff(struct vb2_queue
*q
, unsigned int type
);
866 * vb2_core_expbuf() - Export a buffer as a file descriptor.
867 * @q: pointer to &struct vb2_queue with videobuf2 queue.
868 * @fd: pointer to the file descriptor associated with DMABUF
870 * @type: buffer type.
871 * @index: id number of the buffer.
872 * @plane: index of the plane to be exported, 0 for single plane queues
873 * @flags: file flags for newly created file, as defined at
874 * include/uapi/asm-generic/fcntl.h.
875 * Currently, the only used flag is %O_CLOEXEC.
876 * is supported, refer to manual of open syscall for more details.
879 * Videobuf2 core helper to implement VIDIOC_EXPBUF() operation. It is called
880 * internally by VB2 by an API-specific handler, like ``videobuf2-v4l2.h``.
882 * Return: returns zero on success; an error code otherwise.
884 int vb2_core_expbuf(struct vb2_queue
*q
, int *fd
, unsigned int type
,
885 unsigned int index
, unsigned int plane
, unsigned int flags
);
888 * vb2_core_queue_init() - initialize a videobuf2 queue
889 * @q: pointer to &struct vb2_queue with videobuf2 queue.
890 * This structure should be allocated in driver
892 * The &vb2_queue structure should be allocated by the driver. The driver is
893 * responsible of clearing it's content and setting initial values for some
894 * required entries before calling this function.
898 * The following fields at @q should be set before calling this function:
899 * &vb2_queue->ops, &vb2_queue->mem_ops, &vb2_queue->type.
901 int vb2_core_queue_init(struct vb2_queue
*q
);
904 * vb2_core_queue_release() - stop streaming, release the queue and free memory
905 * @q: pointer to &struct vb2_queue with videobuf2 queue.
907 * This function stops streaming and performs necessary clean ups, including
908 * freeing video buffer memory. The driver is responsible for freeing
909 * the &struct vb2_queue itself.
911 void vb2_core_queue_release(struct vb2_queue
*q
);
914 * vb2_queue_error() - signal a fatal error on the queue
915 * @q: pointer to &struct vb2_queue with videobuf2 queue.
917 * Flag that a fatal unrecoverable error has occurred and wake up all processes
918 * waiting on the queue. Polling will now set %EPOLLERR and queuing and dequeuing
919 * buffers will return %-EIO.
921 * The error flag will be cleared when canceling the queue, either from
922 * vb2_streamoff() or vb2_queue_release(). Drivers should thus not call this
923 * function before starting the stream, otherwise the error flag will remain set
924 * until the queue is released when closing the device node.
926 void vb2_queue_error(struct vb2_queue
*q
);
929 * vb2_mmap() - map video buffers into application address space.
930 * @q: pointer to &struct vb2_queue with videobuf2 queue.
931 * @vma: pointer to &struct vm_area_struct with the vma passed
932 * to the mmap file operation handler in the driver.
934 * Should be called from mmap file operation handler of a driver.
935 * This function maps one plane of one of the available video buffers to
936 * userspace. To map whole video memory allocated on reqbufs, this function
937 * has to be called once per each plane per each buffer previously allocated.
939 * When the userspace application calls mmap, it passes to it an offset returned
940 * to it earlier by the means of &v4l2_ioctl_ops->vidioc_querybuf handler.
941 * That offset acts as a "cookie", which is then used to identify the plane
944 * This function finds a plane with a matching offset and a mapping is performed
945 * by the means of a provided memory operation.
947 * The return values from this function are intended to be directly returned
948 * from the mmap handler in driver.
950 int vb2_mmap(struct vb2_queue
*q
, struct vm_area_struct
*vma
);
954 * vb2_get_unmapped_area - map video buffers into application address space.
955 * @q: pointer to &struct vb2_queue with videobuf2 queue.
956 * @addr: memory address.
958 * @pgoff: page offset.
959 * @flags: memory flags.
961 * This function is used in noMMU platforms to propose address mapping
962 * for a given buffer. It's intended to be used as a handler for the
963 * &file_operations->get_unmapped_area operation.
965 * This is called by the mmap() syscall routines will call this
966 * to get a proposed address for the mapping, when ``!CONFIG_MMU``.
968 unsigned long vb2_get_unmapped_area(struct vb2_queue
*q
,
972 unsigned long flags
);
976 * vb2_core_poll() - implements poll syscall() logic.
977 * @q: pointer to &struct vb2_queue with videobuf2 queue.
978 * @file: &struct file argument passed to the poll
979 * file operation handler.
980 * @wait: &poll_table wait argument passed to the poll
981 * file operation handler.
983 * This function implements poll file operation handler for a driver.
984 * For CAPTURE queues, if a buffer is ready to be dequeued, the userspace will
985 * be informed that the file descriptor of a video device is available for
987 * For OUTPUT queues, if a buffer is ready to be dequeued, the file descriptor
988 * will be reported as available for writing.
990 * The return values from this function are intended to be directly returned
991 * from poll handler in driver.
993 __poll_t
vb2_core_poll(struct vb2_queue
*q
, struct file
*file
,
997 * vb2_read() - implements read() syscall logic.
998 * @q: pointer to &struct vb2_queue with videobuf2 queue.
999 * @data: pointed to target userspace buffer
1000 * @count: number of bytes to read
1001 * @ppos: file handle position tracking pointer
1002 * @nonblock: mode selector (1 means blocking calls, 0 means nonblocking)
1004 size_t vb2_read(struct vb2_queue
*q
, char __user
*data
, size_t count
,
1005 loff_t
*ppos
, int nonblock
);
1007 * vb2_read() - implements write() syscall logic.
1008 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1009 * @data: pointed to target userspace buffer
1010 * @count: number of bytes to write
1011 * @ppos: file handle position tracking pointer
1012 * @nonblock: mode selector (1 means blocking calls, 0 means nonblocking)
1014 size_t vb2_write(struct vb2_queue
*q
, const char __user
*data
, size_t count
,
1015 loff_t
*ppos
, int nonblock
);
1018 * typedef vb2_thread_fnc - callback function for use with vb2_thread.
1020 * @vb: pointer to struct &vb2_buffer.
1021 * @priv: pointer to a private data.
1023 * This is called whenever a buffer is dequeued in the thread.
1025 typedef int (*vb2_thread_fnc
)(struct vb2_buffer
*vb
, void *priv
);
1028 * vb2_thread_start() - start a thread for the given queue.
1029 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1030 * @fnc: &vb2_thread_fnc callback function.
1031 * @priv: priv pointer passed to the callback function.
1032 * @thread_name:the name of the thread. This will be prefixed with "vb2-".
1034 * This starts a thread that will queue and dequeue until an error occurs
1035 * or vb2_thread_stop() is called.
1039 * This function should not be used for anything else but the videobuf2-dvb
1040 * support. If you think you have another good use-case for this, then please
1041 * contact the linux-media mailing list first.
1043 int vb2_thread_start(struct vb2_queue
*q
, vb2_thread_fnc fnc
, void *priv
,
1044 const char *thread_name
);
1047 * vb2_thread_stop() - stop the thread for the given queue.
1048 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1050 int vb2_thread_stop(struct vb2_queue
*q
);
1053 * vb2_is_streaming() - return streaming status of the queue.
1054 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1056 static inline bool vb2_is_streaming(struct vb2_queue
*q
)
1058 return q
->streaming
;
1062 * vb2_fileio_is_active() - return true if fileio is active.
1063 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1065 * This returns true if read() or write() is used to stream the data
1066 * as opposed to stream I/O. This is almost never an important distinction,
1067 * except in rare cases. One such case is that using read() or write() to
1068 * stream a format using %V4L2_FIELD_ALTERNATE is not allowed since there
1069 * is no way you can pass the field information of each buffer to/from
1070 * userspace. A driver that supports this field format should check for
1071 * this in the &vb2_ops->queue_setup op and reject it if this function returns
1074 static inline bool vb2_fileio_is_active(struct vb2_queue
*q
)
1080 * vb2_is_busy() - return busy status of the queue.
1081 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1083 * This function checks if queue has any buffers allocated.
1085 static inline bool vb2_is_busy(struct vb2_queue
*q
)
1087 return (q
->num_buffers
> 0);
1091 * vb2_get_drv_priv() - return driver private data associated with the queue.
1092 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1094 static inline void *vb2_get_drv_priv(struct vb2_queue
*q
)
1100 * vb2_set_plane_payload() - set bytesused for the plane @plane_no.
1101 * @vb: pointer to &struct vb2_buffer to which the plane in
1102 * question belongs to.
1103 * @plane_no: plane number for which payload should be set.
1104 * @size: payload in bytes.
1106 static inline void vb2_set_plane_payload(struct vb2_buffer
*vb
,
1107 unsigned int plane_no
, unsigned long size
)
1109 if (plane_no
< vb
->num_planes
)
1110 vb
->planes
[plane_no
].bytesused
= size
;
1114 * vb2_get_plane_payload() - get bytesused for the plane plane_no
1115 * @vb: pointer to &struct vb2_buffer to which the plane in
1116 * question belongs to.
1117 * @plane_no: plane number for which payload should be set.
1119 static inline unsigned long vb2_get_plane_payload(struct vb2_buffer
*vb
,
1120 unsigned int plane_no
)
1122 if (plane_no
< vb
->num_planes
)
1123 return vb
->planes
[plane_no
].bytesused
;
1128 * vb2_plane_size() - return plane size in bytes.
1129 * @vb: pointer to &struct vb2_buffer to which the plane in
1130 * question belongs to.
1131 * @plane_no: plane number for which size should be returned.
1133 static inline unsigned long
1134 vb2_plane_size(struct vb2_buffer
*vb
, unsigned int plane_no
)
1136 if (plane_no
< vb
->num_planes
)
1137 return vb
->planes
[plane_no
].length
;
1142 * vb2_start_streaming_called() - return streaming status of driver.
1143 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1145 static inline bool vb2_start_streaming_called(struct vb2_queue
*q
)
1147 return q
->start_streaming_called
;
1151 * vb2_clear_last_buffer_dequeued() - clear last buffer dequeued flag of queue.
1152 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1154 static inline void vb2_clear_last_buffer_dequeued(struct vb2_queue
*q
)
1156 q
->last_buffer_dequeued
= false;
1160 * The following functions are not part of the vb2 core API, but are useful
1161 * functions for videobuf2-*.
1165 * vb2_buffer_in_use() - return true if the buffer is in use and
1166 * the queue cannot be freed (by the means of VIDIOC_REQBUFS(0)) call.
1168 * @vb: buffer for which plane size should be returned.
1169 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1171 bool vb2_buffer_in_use(struct vb2_queue
*q
, struct vb2_buffer
*vb
);
1174 * vb2_verify_memory_type() - Check whether the memory type and buffer type
1175 * passed to a buffer operation are compatible with the queue.
1177 * @q: pointer to &struct vb2_queue with videobuf2 queue.
1178 * @memory: memory model, as defined by enum &vb2_memory.
1179 * @type: private buffer type whose content is defined by the vb2-core
1180 * caller. For example, for V4L2, it should match
1181 * the types defined on enum &v4l2_buf_type.
1183 int vb2_verify_memory_type(struct vb2_queue
*q
,
1184 enum vb2_memory memory
, unsigned int type
);
1187 * vb2_request_object_is_buffer() - return true if the object is a buffer
1189 * @obj: the request object.
1191 bool vb2_request_object_is_buffer(struct media_request_object
*obj
);
1194 * vb2_request_buffer_cnt() - return the number of buffers in the request
1196 * @req: the request.
1198 unsigned int vb2_request_buffer_cnt(struct media_request
*req
);
1200 #endif /* _MEDIA_VIDEOBUF2_CORE_H */