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>
20 #define VB2_MAX_FRAME (32)
21 #define VB2_MAX_PLANES (8)
24 VB2_MEMORY_UNKNOWN
= 0,
26 VB2_MEMORY_USERPTR
= 2,
27 VB2_MEMORY_DMABUF
= 4,
31 struct vb2_fileio_data
;
32 struct vb2_threadio_data
;
35 * struct vb2_mem_ops - memory handling/memory allocator operations
36 * @alloc: allocate video memory and, optionally, allocator private data,
37 * return NULL on failure or a pointer to allocator private,
38 * per-buffer data on success; the returned private structure
39 * will then be passed as buf_priv argument to other ops in this
40 * structure. Additional gfp_flags to use when allocating the
41 * are also passed to this operation. These flags are from the
42 * gfp_flags field of vb2_queue.
43 * @put: inform the allocator that the buffer will no longer be used;
44 * usually will result in the allocator freeing the buffer (if
45 * no other users of this buffer are present); the buf_priv
46 * argument is the allocator private per-buffer structure
47 * previously returned from the alloc callback.
48 * @get_dmabuf: acquire userspace memory for a hardware operation; used for
49 * DMABUF memory types.
50 * @get_userptr: acquire userspace memory for a hardware operation; used for
51 * USERPTR memory types; vaddr is the address passed to the
52 * videobuf layer when queuing a video buffer of USERPTR type;
53 * should return an allocator private per-buffer structure
54 * associated with the buffer on success, NULL on failure;
55 * the returned private structure will then be passed as buf_priv
56 * argument to other ops in this structure.
57 * @put_userptr: inform the allocator that a USERPTR buffer will no longer
59 * @attach_dmabuf: attach a shared struct dma_buf for a hardware operation;
60 * used for DMABUF memory types; alloc_ctx is the alloc context
61 * dbuf is the shared dma_buf; returns NULL on failure;
62 * allocator private per-buffer structure on success;
63 * this needs to be used for further accesses to the buffer.
64 * @detach_dmabuf: inform the exporter of the buffer that the current DMABUF
65 * buffer is no longer used; the buf_priv argument is the
66 * allocator private per-buffer structure previously returned
67 * from the attach_dmabuf callback.
68 * @map_dmabuf: request for access to the dmabuf from allocator; the allocator
69 * of dmabuf is informed that this driver is going to use the
71 * @unmap_dmabuf: releases access control to the dmabuf - allocator is notified
72 * that this driver is done using the dmabuf for now.
73 * @prepare: called every time the buffer is passed from userspace to the
74 * driver, useful for cache synchronisation, optional.
75 * @finish: called every time the buffer is passed back from the driver
76 * to the userspace, also optional.
77 * @vaddr: return a kernel virtual address to a given memory buffer
78 * associated with the passed private structure or NULL if no
79 * such mapping exists.
80 * @cookie: return allocator specific cookie for a given memory buffer
81 * associated with the passed private structure or NULL if not
83 * @num_users: return the current number of users of a memory buffer;
84 * return 1 if the videobuf layer (or actually the driver using
85 * it) is the only user.
86 * @mmap: setup a userspace mapping for a given memory buffer under
87 * the provided virtual memory region.
89 * Required ops for USERPTR types: get_userptr, put_userptr.
90 * Required ops for MMAP types: alloc, put, num_users, mmap.
91 * Required ops for read/write access types: alloc, put, num_users, vaddr.
92 * Required ops for DMABUF types: attach_dmabuf, detach_dmabuf, map_dmabuf,
96 void *(*alloc
)(void *alloc_ctx
, unsigned long size
,
97 enum dma_data_direction dma_dir
,
99 void (*put
)(void *buf_priv
);
100 struct dma_buf
*(*get_dmabuf
)(void *buf_priv
, unsigned long flags
);
102 void *(*get_userptr
)(void *alloc_ctx
, unsigned long vaddr
,
104 enum dma_data_direction dma_dir
);
105 void (*put_userptr
)(void *buf_priv
);
107 void (*prepare
)(void *buf_priv
);
108 void (*finish
)(void *buf_priv
);
110 void *(*attach_dmabuf
)(void *alloc_ctx
, struct dma_buf
*dbuf
,
112 enum dma_data_direction dma_dir
);
113 void (*detach_dmabuf
)(void *buf_priv
);
114 int (*map_dmabuf
)(void *buf_priv
);
115 void (*unmap_dmabuf
)(void *buf_priv
);
117 void *(*vaddr
)(void *buf_priv
);
118 void *(*cookie
)(void *buf_priv
);
120 unsigned int (*num_users
)(void *buf_priv
);
122 int (*mmap
)(void *buf_priv
, struct vm_area_struct
*vma
);
126 * struct vb2_plane - plane information
127 * @mem_priv: private data with this plane
128 * @dbuf: dma_buf - shared buffer object
129 * @dbuf_mapped: flag to show whether dbuf is mapped or not
130 * @bytesused: number of bytes occupied by data in the plane (payload)
131 * @length: size of this plane (NOT the payload) in bytes
132 * @offset: when memory in the associated struct vb2_buffer is
133 * VB2_MEMORY_MMAP, equals the offset from the start of
134 * the device memory for this plane (or is a "cookie" that
135 * should be passed to mmap() called on the video node)
136 * @userptr: when memory is VB2_MEMORY_USERPTR, a userspace pointer
137 * pointing to this plane
138 * @fd: when memory is VB2_MEMORY_DMABUF, a userspace file
139 * descriptor associated with this plane
140 * @m: Union with memtype-specific data (@offset, @userptr or
142 * @data_offset: offset in the plane to the start of data; usually 0,
143 * unless there is a header in front of the data
144 * Should contain enough information to be able to cover all the fields
145 * of struct v4l2_plane at videodev2.h
149 struct dma_buf
*dbuf
;
150 unsigned int dbuf_mapped
;
151 unsigned int bytesused
;
155 unsigned long userptr
;
158 unsigned int data_offset
;
162 * enum vb2_io_modes - queue access methods
163 * @VB2_MMAP: driver supports MMAP with streaming API
164 * @VB2_USERPTR: driver supports USERPTR with streaming API
165 * @VB2_READ: driver supports read() style access
166 * @VB2_WRITE: driver supports write() style access
167 * @VB2_DMABUF: driver supports DMABUF with streaming API
171 VB2_USERPTR
= (1 << 1),
173 VB2_WRITE
= (1 << 3),
174 VB2_DMABUF
= (1 << 4),
178 * enum vb2_buffer_state - current video buffer state
179 * @VB2_BUF_STATE_DEQUEUED: buffer under userspace control
180 * @VB2_BUF_STATE_PREPARING: buffer is being prepared in videobuf
181 * @VB2_BUF_STATE_PREPARED: buffer prepared in videobuf and by the driver
182 * @VB2_BUF_STATE_QUEUED: buffer queued in videobuf, but not in driver
183 * @VB2_BUF_STATE_REQUEUEING: re-queue a buffer to the driver
184 * @VB2_BUF_STATE_ACTIVE: buffer queued in driver and possibly used
185 * in a hardware operation
186 * @VB2_BUF_STATE_DONE: buffer returned from driver to videobuf, but
187 * not yet dequeued to userspace
188 * @VB2_BUF_STATE_ERROR: same as above, but the operation on the buffer
189 * has ended with an error, which will be reported
190 * to the userspace when it is dequeued
192 enum vb2_buffer_state
{
193 VB2_BUF_STATE_DEQUEUED
,
194 VB2_BUF_STATE_PREPARING
,
195 VB2_BUF_STATE_PREPARED
,
196 VB2_BUF_STATE_QUEUED
,
197 VB2_BUF_STATE_REQUEUEING
,
198 VB2_BUF_STATE_ACTIVE
,
206 * struct vb2_buffer - represents a video buffer
207 * @vb2_queue: the queue to which this driver belongs
208 * @index: id number of the buffer
210 * @memory: the method, in which the actual data is passed
211 * @num_planes: number of planes in the buffer
212 * on an internal driver queue
213 * @planes: private per-plane information; do not change
216 struct vb2_queue
*vb2_queue
;
220 unsigned int num_planes
;
221 struct vb2_plane planes
[VB2_MAX_PLANES
];
223 /* private: internal use only
225 * state: current buffer state; do not change
226 * queued_entry: entry on the queued buffers list, which holds
227 * all buffers queued from userspace
228 * done_entry: entry on the list that stores all buffers ready
229 * to be dequeued to userspace
231 enum vb2_buffer_state state
;
233 struct list_head queued_entry
;
234 struct list_head done_entry
;
235 #ifdef CONFIG_VIDEO_ADV_DEBUG
237 * Counters for how often these buffer-related ops are
238 * called. Used to check for unbalanced ops.
242 u32 cnt_mem_get_dmabuf
;
243 u32 cnt_mem_get_userptr
;
244 u32 cnt_mem_put_userptr
;
247 u32 cnt_mem_attach_dmabuf
;
248 u32 cnt_mem_detach_dmabuf
;
249 u32 cnt_mem_map_dmabuf
;
250 u32 cnt_mem_unmap_dmabuf
;
253 u32 cnt_mem_num_users
;
262 /* This counts the number of calls to vb2_buffer_done() */
268 * struct vb2_ops - driver-specific callbacks
270 * @queue_setup: called from VIDIOC_REQBUFS and VIDIOC_CREATE_BUFS
271 * handlers before memory allocation, or, if
272 * *num_planes != 0, after the allocation to verify a
273 * smaller number of buffers. Driver should return
274 * the required number of buffers in *num_buffers, the
275 * required number of planes per buffer in *num_planes; the
276 * size of each plane should be set in the sizes[] array
277 * and optional per-plane allocator specific context in the
278 * alloc_ctxs[] array. When called from VIDIOC_REQBUFS,
279 * fmt == NULL, the driver has to use the currently
280 * configured format and *num_buffers is the total number
281 * of buffers, that are being allocated. When called from
282 * VIDIOC_CREATE_BUFS, fmt != NULL and it describes the
283 * target frame format (if the format isn't valid the
284 * callback must return -EINVAL). In this case *num_buffers
285 * are being allocated additionally to q->num_buffers.
286 * @wait_prepare: release any locks taken while calling vb2 functions;
287 * it is called before an ioctl needs to wait for a new
288 * buffer to arrive; required to avoid a deadlock in
289 * blocking access type.
290 * @wait_finish: reacquire all locks released in the previous callback;
291 * required to continue operation after sleeping while
292 * waiting for a new buffer to arrive.
293 * @buf_init: called once after allocating a buffer (in MMAP case)
294 * or after acquiring a new USERPTR buffer; drivers may
295 * perform additional buffer-related initialization;
296 * initialization failure (return != 0) will prevent
297 * queue setup from completing successfully; optional.
298 * @buf_prepare: called every time the buffer is queued from userspace
299 * and from the VIDIOC_PREPARE_BUF ioctl; drivers may
300 * perform any initialization required before each
301 * hardware operation in this callback; drivers can
302 * access/modify the buffer here as it is still synced for
303 * the CPU; drivers that support VIDIOC_CREATE_BUFS must
304 * also validate the buffer size; if an error is returned,
305 * the buffer will not be queued in driver; optional.
306 * @buf_finish: called before every dequeue of the buffer back to
307 * userspace; the buffer is synced for the CPU, so drivers
308 * can access/modify the buffer contents; drivers may
309 * perform any operations required before userspace
310 * accesses the buffer; optional. The buffer state can be
311 * one of the following: DONE and ERROR occur while
312 * streaming is in progress, and the PREPARED state occurs
313 * when the queue has been canceled and all pending
314 * buffers are being returned to their default DEQUEUED
315 * state. Typically you only have to do something if the
316 * state is VB2_BUF_STATE_DONE, since in all other cases
317 * the buffer contents will be ignored anyway.
318 * @buf_cleanup: called once before the buffer is freed; drivers may
319 * perform any additional cleanup; optional.
320 * @start_streaming: called once to enter 'streaming' state; the driver may
321 * receive buffers with @buf_queue callback before
322 * @start_streaming is called; the driver gets the number
323 * of already queued buffers in count parameter; driver
324 * can return an error if hardware fails, in that case all
325 * buffers that have been already given by the @buf_queue
326 * callback are to be returned by the driver by calling
327 * @vb2_buffer_done(VB2_BUF_STATE_QUEUED).
328 * If you need a minimum number of buffers before you can
329 * start streaming, then set @min_buffers_needed in the
330 * vb2_queue structure. If that is non-zero then
331 * start_streaming won't be called until at least that
332 * many buffers have been queued up by userspace.
333 * @stop_streaming: called when 'streaming' state must be disabled; driver
334 * should stop any DMA transactions or wait until they
335 * finish and give back all buffers it got from buf_queue()
336 * callback by calling @vb2_buffer_done() with either
337 * VB2_BUF_STATE_DONE or VB2_BUF_STATE_ERROR; may use
338 * vb2_wait_for_all_buffers() function
339 * @buf_queue: passes buffer vb to the driver; driver may start
340 * hardware operation on this buffer; driver should give
341 * the buffer back by calling vb2_buffer_done() function;
342 * it is allways called after calling STREAMON ioctl;
343 * might be called before start_streaming callback if user
344 * pre-queued buffers before calling STREAMON.
347 int (*queue_setup
)(struct vb2_queue
*q
, const void *parg
,
348 unsigned int *num_buffers
, unsigned int *num_planes
,
349 unsigned int sizes
[], void *alloc_ctxs
[]);
351 void (*wait_prepare
)(struct vb2_queue
*q
);
352 void (*wait_finish
)(struct vb2_queue
*q
);
354 int (*buf_init
)(struct vb2_buffer
*vb
);
355 int (*buf_prepare
)(struct vb2_buffer
*vb
);
356 void (*buf_finish
)(struct vb2_buffer
*vb
);
357 void (*buf_cleanup
)(struct vb2_buffer
*vb
);
359 int (*start_streaming
)(struct vb2_queue
*q
, unsigned int count
);
360 void (*stop_streaming
)(struct vb2_queue
*q
);
362 void (*buf_queue
)(struct vb2_buffer
*vb
);
366 int (*fill_user_buffer
)(struct vb2_buffer
*vb
, void *pb
);
367 int (*fill_vb2_buffer
)(struct vb2_buffer
*vb
, const void *pb
,
368 struct vb2_plane
*planes
);
369 int (*set_timestamp
)(struct vb2_buffer
*vb
, const void *pb
);
373 * struct vb2_queue - a videobuf queue
375 * @type: private buffer type whose content is defined by the vb2-core
376 * caller. For example, for V4L2, it should match
377 * the V4L2_BUF_TYPE_* in include/uapi/linux/videodev2.h
378 * @io_modes: supported io methods (see vb2_io_modes enum)
379 * @fileio_read_once: report EOF after reading the first buffer
380 * @fileio_write_immediately: queue buffer after each write() call
381 * @allow_zero_bytesused: allow bytesused == 0 to be passed to the driver
382 * @lock: pointer to a mutex that protects the vb2_queue struct. The
383 * driver can set this to a mutex to let the v4l2 core serialize
384 * the queuing ioctls. If the driver wants to handle locking
385 * itself, then this should be set to NULL. This lock is not used
386 * by the videobuf2 core API.
387 * @owner: The filehandle that 'owns' the buffers, i.e. the filehandle
388 * that called reqbufs, create_buffers or started fileio.
389 * This field is not used by the videobuf2 core API, but it allows
390 * drivers to easily associate an owner filehandle with the queue.
391 * @ops: driver-specific callbacks
392 * @mem_ops: memory allocator specific callbacks
393 * @buf_ops: callbacks to deliver buffer information
394 * between user-space and kernel-space
395 * @drv_priv: driver private data
396 * @buf_struct_size: size of the driver-specific buffer structure;
397 * "0" indicates the driver doesn't want to use a custom buffer
398 * structure type. for example, sizeof(struct vb2_v4l2_buffer)
399 * will be used for v4l2.
400 * @timestamp_flags: Timestamp flags; V4L2_BUF_FLAG_TIMESTAMP_* and
401 * V4L2_BUF_FLAG_TSTAMP_SRC_*
402 * @gfp_flags: additional gfp flags used when allocating the buffers.
403 * Typically this is 0, but it may be e.g. GFP_DMA or __GFP_DMA32
404 * to force the buffer allocation to a specific memory zone.
405 * @min_buffers_needed: the minimum number of buffers needed before
406 * start_streaming() can be called. Used when a DMA engine
407 * cannot be started unless at least this number of buffers
408 * have been queued into the driver.
411 * Private elements (won't appear at the DocBook):
412 * @mmap_lock: private mutex used when buffers are allocated/freed/mmapped
413 * @memory: current memory type used
414 * @bufs: videobuf buffer structures
415 * @num_buffers: number of allocated/used buffers
416 * @queued_list: list of buffers currently queued from userspace
417 * @queued_count: number of buffers queued and ready for streaming.
418 * @owned_by_drv_count: number of buffers owned by the driver
419 * @done_list: list of buffers ready to be dequeued to userspace
420 * @done_lock: lock to protect done_list list
421 * @done_wq: waitqueue for processes waiting for buffers ready to be dequeued
422 * @alloc_ctx: memory type/allocator-specific contexts for each plane
423 * @streaming: current streaming state
424 * @start_streaming_called: start_streaming() was called successfully and we
426 * @error: a fatal error occurred on the queue
427 * @waiting_for_buffers: used in poll() to check if vb2 is still waiting for
428 * buffers. Only set for capture queues if qbuf has not yet been
429 * called since poll() needs to return POLLERR in that situation.
430 * @is_multiplanar: set if buffer type is multiplanar
431 * @is_output: set if buffer type is output
432 * @last_buffer_dequeued: used in poll() and DQBUF to immediately return if the
433 * last decoded buffer was already dequeued. Set for capture queues
434 * when a buffer with the V4L2_BUF_FLAG_LAST is dequeued.
435 * @fileio: file io emulator internal data, used only if emulator is active
436 * @threadio: thread io internal data, used only if thread is active
440 unsigned int io_modes
;
441 unsigned fileio_read_once
:1;
442 unsigned fileio_write_immediately
:1;
443 unsigned allow_zero_bytesused
:1;
448 const struct vb2_ops
*ops
;
449 const struct vb2_mem_ops
*mem_ops
;
450 const struct vb2_buf_ops
*buf_ops
;
453 unsigned int buf_struct_size
;
456 u32 min_buffers_needed
;
458 /* private: internal use only */
459 struct mutex mmap_lock
;
461 struct vb2_buffer
*bufs
[VB2_MAX_FRAME
];
462 unsigned int num_buffers
;
464 struct list_head queued_list
;
465 unsigned int queued_count
;
467 atomic_t owned_by_drv_count
;
468 struct list_head done_list
;
469 spinlock_t done_lock
;
470 wait_queue_head_t done_wq
;
472 void *alloc_ctx
[VB2_MAX_PLANES
];
473 unsigned int plane_sizes
[VB2_MAX_PLANES
];
475 unsigned int streaming
:1;
476 unsigned int start_streaming_called
:1;
477 unsigned int error
:1;
478 unsigned int waiting_for_buffers
:1;
479 unsigned int is_multiplanar
:1;
480 unsigned int is_output
:1;
481 unsigned int last_buffer_dequeued
:1;
483 struct vb2_fileio_data
*fileio
;
484 struct vb2_threadio_data
*threadio
;
486 #ifdef CONFIG_VIDEO_ADV_DEBUG
488 * Counters for how often these queue-related ops are
489 * called. Used to check for unbalanced ops.
492 u32 cnt_wait_prepare
;
494 u32 cnt_start_streaming
;
495 u32 cnt_stop_streaming
;
499 void *vb2_plane_vaddr(struct vb2_buffer
*vb
, unsigned int plane_no
);
500 void *vb2_plane_cookie(struct vb2_buffer
*vb
, unsigned int plane_no
);
502 void vb2_buffer_done(struct vb2_buffer
*vb
, enum vb2_buffer_state state
);
503 void vb2_discard_done(struct vb2_queue
*q
);
504 int vb2_wait_for_all_buffers(struct vb2_queue
*q
);
506 int vb2_core_querybuf(struct vb2_queue
*q
, unsigned int index
, void *pb
);
507 int vb2_core_reqbufs(struct vb2_queue
*q
, enum vb2_memory memory
,
508 unsigned int *count
);
509 int vb2_core_create_bufs(struct vb2_queue
*q
, enum vb2_memory memory
,
510 unsigned int *count
, const void *parg
);
511 int vb2_core_prepare_buf(struct vb2_queue
*q
, unsigned int index
, void *pb
);
512 int vb2_core_qbuf(struct vb2_queue
*q
, unsigned int index
, void *pb
);
513 int vb2_core_dqbuf(struct vb2_queue
*q
, void *pb
, bool nonblocking
);
515 int vb2_core_streamon(struct vb2_queue
*q
, unsigned int type
);
516 int vb2_core_streamoff(struct vb2_queue
*q
, unsigned int type
);
518 int vb2_core_expbuf(struct vb2_queue
*q
, int *fd
, unsigned int type
,
519 unsigned int index
, unsigned int plane
, unsigned int flags
);
521 int vb2_core_queue_init(struct vb2_queue
*q
);
522 void vb2_core_queue_release(struct vb2_queue
*q
);
524 void vb2_queue_error(struct vb2_queue
*q
);
526 int vb2_mmap(struct vb2_queue
*q
, struct vm_area_struct
*vma
);
528 unsigned long vb2_get_unmapped_area(struct vb2_queue
*q
,
532 unsigned long flags
);
536 * vb2_is_streaming() - return streaming status of the queue
539 static inline bool vb2_is_streaming(struct vb2_queue
*q
)
545 * vb2_fileio_is_active() - return true if fileio is active.
548 * This returns true if read() or write() is used to stream the data
549 * as opposed to stream I/O. This is almost never an important distinction,
550 * except in rare cases. One such case is that using read() or write() to
551 * stream a format using V4L2_FIELD_ALTERNATE is not allowed since there
552 * is no way you can pass the field information of each buffer to/from
553 * userspace. A driver that supports this field format should check for
554 * this in the queue_setup op and reject it if this function returns true.
556 static inline bool vb2_fileio_is_active(struct vb2_queue
*q
)
562 * vb2_is_busy() - return busy status of the queue
565 * This function checks if queue has any buffers allocated.
567 static inline bool vb2_is_busy(struct vb2_queue
*q
)
569 return (q
->num_buffers
> 0);
573 * vb2_get_drv_priv() - return driver private data associated with the queue
576 static inline void *vb2_get_drv_priv(struct vb2_queue
*q
)
582 * vb2_set_plane_payload() - set bytesused for the plane plane_no
583 * @vb: buffer for which plane payload should be set
584 * @plane_no: plane number for which payload should be set
585 * @size: payload in bytes
587 static inline void vb2_set_plane_payload(struct vb2_buffer
*vb
,
588 unsigned int plane_no
, unsigned long size
)
590 if (plane_no
< vb
->num_planes
)
591 vb
->planes
[plane_no
].bytesused
= size
;
595 * vb2_get_plane_payload() - get bytesused for the plane plane_no
596 * @vb: buffer for which plane payload should be set
597 * @plane_no: plane number for which payload should be set
599 static inline unsigned long vb2_get_plane_payload(struct vb2_buffer
*vb
,
600 unsigned int plane_no
)
602 if (plane_no
< vb
->num_planes
)
603 return vb
->planes
[plane_no
].bytesused
;
608 * vb2_plane_size() - return plane size in bytes
609 * @vb: buffer for which plane size should be returned
610 * @plane_no: plane number for which size should be returned
612 static inline unsigned long
613 vb2_plane_size(struct vb2_buffer
*vb
, unsigned int plane_no
)
615 if (plane_no
< vb
->num_planes
)
616 return vb
->planes
[plane_no
].length
;
621 * vb2_start_streaming_called() - return streaming status of driver
624 static inline bool vb2_start_streaming_called(struct vb2_queue
*q
)
626 return q
->start_streaming_called
;
630 * vb2_clear_last_buffer_dequeued() - clear last buffer dequeued flag of queue
633 static inline void vb2_clear_last_buffer_dequeued(struct vb2_queue
*q
)
635 q
->last_buffer_dequeued
= false;
638 #endif /* _MEDIA_VIDEOBUF2_CORE_H */