2 * videobuf2-core.h - V4L2 driver helper 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/videodev2.h>
19 #include <linux/dma-buf.h>
22 struct vb2_fileio_data
;
25 * struct vb2_mem_ops - memory handling/memory allocator operations
26 * @alloc: allocate video memory and, optionally, allocator private data,
27 * return NULL on failure or a pointer to allocator private,
28 * per-buffer data on success; the returned private structure
29 * will then be passed as buf_priv argument to other ops in this
30 * structure. Additional gfp_flags to use when allocating the
31 * are also passed to this operation. These flags are from the
32 * gfp_flags field of vb2_queue.
33 * @put: inform the allocator that the buffer will no longer be used;
34 * usually will result in the allocator freeing the buffer (if
35 * no other users of this buffer are present); the buf_priv
36 * argument is the allocator private per-buffer structure
37 * previously returned from the alloc callback.
38 * @get_userptr: acquire userspace memory for a hardware operation; used for
39 * USERPTR memory types; vaddr is the address passed to the
40 * videobuf layer when queuing a video buffer of USERPTR type;
41 * should return an allocator private per-buffer structure
42 * associated with the buffer on success, NULL on failure;
43 * the returned private structure will then be passed as buf_priv
44 * argument to other ops in this structure.
45 * @put_userptr: inform the allocator that a USERPTR buffer will no longer
47 * @attach_dmabuf: attach a shared struct dma_buf for a hardware operation;
48 * used for DMABUF memory types; alloc_ctx is the alloc context
49 * dbuf is the shared dma_buf; returns NULL on failure;
50 * allocator private per-buffer structure on success;
51 * this needs to be used for further accesses to the buffer.
52 * @detach_dmabuf: inform the exporter of the buffer that the current DMABUF
53 * buffer is no longer used; the buf_priv argument is the
54 * allocator private per-buffer structure previously returned
55 * from the attach_dmabuf callback.
56 * @map_dmabuf: request for access to the dmabuf from allocator; the allocator
57 * of dmabuf is informed that this driver is going to use the
59 * @unmap_dmabuf: releases access control to the dmabuf - allocator is notified
60 * that this driver is done using the dmabuf for now.
61 * @prepare: called every time the buffer is passed from userspace to the
62 * driver, useful for cache synchronisation, optional.
63 * @finish: called every time the buffer is passed back from the driver
64 * to the userspace, also optional.
65 * @vaddr: return a kernel virtual address to a given memory buffer
66 * associated with the passed private structure or NULL if no
67 * such mapping exists.
68 * @cookie: return allocator specific cookie for a given memory buffer
69 * associated with the passed private structure or NULL if not
71 * @num_users: return the current number of users of a memory buffer;
72 * return 1 if the videobuf layer (or actually the driver using
73 * it) is the only user.
74 * @mmap: setup a userspace mapping for a given memory buffer under
75 * the provided virtual memory region.
77 * Required ops for USERPTR types: get_userptr, put_userptr.
78 * Required ops for MMAP types: alloc, put, num_users, mmap.
79 * Required ops for read/write access types: alloc, put, num_users, vaddr.
80 * Required ops for DMABUF types: attach_dmabuf, detach_dmabuf, map_dmabuf,
84 void *(*alloc
)(void *alloc_ctx
, unsigned long size
, gfp_t gfp_flags
);
85 void (*put
)(void *buf_priv
);
86 struct dma_buf
*(*get_dmabuf
)(void *buf_priv
, unsigned long flags
);
88 void *(*get_userptr
)(void *alloc_ctx
, unsigned long vaddr
,
89 unsigned long size
, int write
);
90 void (*put_userptr
)(void *buf_priv
);
92 void (*prepare
)(void *buf_priv
);
93 void (*finish
)(void *buf_priv
);
95 void *(*attach_dmabuf
)(void *alloc_ctx
, struct dma_buf
*dbuf
,
96 unsigned long size
, int write
);
97 void (*detach_dmabuf
)(void *buf_priv
);
98 int (*map_dmabuf
)(void *buf_priv
);
99 void (*unmap_dmabuf
)(void *buf_priv
);
101 void *(*vaddr
)(void *buf_priv
);
102 void *(*cookie
)(void *buf_priv
);
104 unsigned int (*num_users
)(void *buf_priv
);
106 int (*mmap
)(void *buf_priv
, struct vm_area_struct
*vma
);
111 struct dma_buf
*dbuf
;
112 unsigned int dbuf_mapped
;
116 * enum vb2_io_modes - queue access methods
117 * @VB2_MMAP: driver supports MMAP with streaming API
118 * @VB2_USERPTR: driver supports USERPTR with streaming API
119 * @VB2_READ: driver supports read() style access
120 * @VB2_WRITE: driver supports write() style access
121 * @VB2_DMABUF: driver supports DMABUF with streaming API
125 VB2_USERPTR
= (1 << 1),
127 VB2_WRITE
= (1 << 3),
128 VB2_DMABUF
= (1 << 4),
132 * enum vb2_fileio_flags - flags for selecting a mode of the file io emulator,
133 * by default the 'streaming' style is used by the file io emulator
134 * @VB2_FILEIO_READ_ONCE: report EOF after reading the first buffer
135 * @VB2_FILEIO_WRITE_IMMEDIATELY: queue buffer after each write() call
137 enum vb2_fileio_flags
{
138 VB2_FILEIO_READ_ONCE
= (1 << 0),
139 VB2_FILEIO_WRITE_IMMEDIATELY
= (1 << 1),
143 * enum vb2_buffer_state - current video buffer state
144 * @VB2_BUF_STATE_DEQUEUED: buffer under userspace control
145 * @VB2_BUF_STATE_PREPARING: buffer is being prepared in videobuf
146 * @VB2_BUF_STATE_PREPARED: buffer prepared in videobuf and by the driver
147 * @VB2_BUF_STATE_QUEUED: buffer queued in videobuf, but not in driver
148 * @VB2_BUF_STATE_ACTIVE: buffer queued in driver and possibly used
149 * in a hardware operation
150 * @VB2_BUF_STATE_DONE: buffer returned from driver to videobuf, but
151 * not yet dequeued to userspace
152 * @VB2_BUF_STATE_ERROR: same as above, but the operation on the buffer
153 * has ended with an error, which will be reported
154 * to the userspace when it is dequeued
156 enum vb2_buffer_state
{
157 VB2_BUF_STATE_DEQUEUED
,
158 VB2_BUF_STATE_PREPARING
,
159 VB2_BUF_STATE_PREPARED
,
160 VB2_BUF_STATE_QUEUED
,
161 VB2_BUF_STATE_ACTIVE
,
169 * struct vb2_buffer - represents a video buffer
170 * @v4l2_buf: struct v4l2_buffer associated with this buffer; can
171 * be read by the driver and relevant entries can be
172 * changed by the driver in case of CAPTURE types
173 * (such as timestamp)
174 * @v4l2_planes: struct v4l2_planes associated with this buffer; can
175 * be read by the driver and relevant entries can be
176 * changed by the driver in case of CAPTURE types
177 * (such as bytesused); NOTE that even for single-planar
178 * types, the v4l2_planes[0] struct should be used
179 * instead of v4l2_buf for filling bytesused - drivers
180 * should use the vb2_set_plane_payload() function for that
181 * @vb2_queue: the queue to which this driver belongs
182 * @num_planes: number of planes in the buffer
183 * on an internal driver queue
184 * @state: current buffer state; do not change
185 * @queued_entry: entry on the queued buffers list, which holds all
186 * buffers queued from userspace
187 * @done_entry: entry on the list that stores all buffers ready to
188 * be dequeued to userspace
189 * @planes: private per-plane information; do not change
192 struct v4l2_buffer v4l2_buf
;
193 struct v4l2_plane v4l2_planes
[VIDEO_MAX_PLANES
];
195 struct vb2_queue
*vb2_queue
;
197 unsigned int num_planes
;
199 /* Private: internal use only */
200 enum vb2_buffer_state state
;
202 struct list_head queued_entry
;
203 struct list_head done_entry
;
205 struct vb2_plane planes
[VIDEO_MAX_PLANES
];
207 #ifdef CONFIG_VIDEO_ADV_DEBUG
209 * Counters for how often these buffer-related ops are
210 * called. Used to check for unbalanced ops.
214 u32 cnt_mem_get_dmabuf
;
215 u32 cnt_mem_get_userptr
;
216 u32 cnt_mem_put_userptr
;
219 u32 cnt_mem_attach_dmabuf
;
220 u32 cnt_mem_detach_dmabuf
;
221 u32 cnt_mem_map_dmabuf
;
222 u32 cnt_mem_unmap_dmabuf
;
225 u32 cnt_mem_num_users
;
234 /* This counts the number of calls to vb2_buffer_done() */
240 * struct vb2_ops - driver-specific callbacks
242 * @queue_setup: called from VIDIOC_REQBUFS and VIDIOC_CREATE_BUFS
243 * handlers before memory allocation, or, if
244 * *num_planes != 0, after the allocation to verify a
245 * smaller number of buffers. Driver should return
246 * the required number of buffers in *num_buffers, the
247 * required number of planes per buffer in *num_planes; the
248 * size of each plane should be set in the sizes[] array
249 * and optional per-plane allocator specific context in the
250 * alloc_ctxs[] array. When called from VIDIOC_REQBUFS,
251 * fmt == NULL, the driver has to use the currently
252 * configured format and *num_buffers is the total number
253 * of buffers, that are being allocated. When called from
254 * VIDIOC_CREATE_BUFS, fmt != NULL and it describes the
255 * target frame format (if the format isn't valid the
256 * callback must return -EINVAL). In this case *num_buffers
257 * are being allocated additionally to q->num_buffers.
258 * @wait_prepare: release any locks taken while calling vb2 functions;
259 * it is called before an ioctl needs to wait for a new
260 * buffer to arrive; required to avoid a deadlock in
261 * blocking access type.
262 * @wait_finish: reacquire all locks released in the previous callback;
263 * required to continue operation after sleeping while
264 * waiting for a new buffer to arrive.
265 * @buf_init: called once after allocating a buffer (in MMAP case)
266 * or after acquiring a new USERPTR buffer; drivers may
267 * perform additional buffer-related initialization;
268 * initialization failure (return != 0) will prevent
269 * queue setup from completing successfully; optional.
270 * @buf_prepare: called every time the buffer is queued from userspace
271 * and from the VIDIOC_PREPARE_BUF ioctl; drivers may
272 * perform any initialization required before each hardware
273 * operation in this callback; drivers that support
274 * VIDIOC_CREATE_BUFS must also validate the buffer size;
275 * if an error is returned, the buffer will not be queued
276 * in driver; optional.
277 * @buf_finish: called before every dequeue of the buffer back to
278 * userspace; drivers may perform any operations required
279 * before userspace accesses the buffer; optional. The
280 * buffer state can be one of the following: DONE and
281 * ERROR occur while streaming is in progress, and the
282 * PREPARED state occurs when the queue has been canceled
283 * and all pending buffers are being returned to their
284 * default DEQUEUED state. Typically you only have to do
285 * something if the state is VB2_BUF_STATE_DONE, since in
286 * all other cases the buffer contents will be ignored
288 * @buf_cleanup: called once before the buffer is freed; drivers may
289 * perform any additional cleanup; optional.
290 * @start_streaming: called once to enter 'streaming' state; the driver may
291 * receive buffers with @buf_queue callback before
292 * @start_streaming is called; the driver gets the number
293 * of already queued buffers in count parameter; driver
294 * can return an error if hardware fails, in that case all
295 * buffers that have been already given by the @buf_queue
296 * callback are invalidated.
297 * If there were not enough queued buffers to start
298 * streaming, then this callback returns -ENOBUFS, and the
299 * vb2 core will retry calling @start_streaming when a new
301 * @stop_streaming: called when 'streaming' state must be disabled; driver
302 * should stop any DMA transactions or wait until they
303 * finish and give back all buffers it got from buf_queue()
304 * callback; may use vb2_wait_for_all_buffers() function
305 * @buf_queue: passes buffer vb to the driver; driver may start
306 * hardware operation on this buffer; driver should give
307 * the buffer back by calling vb2_buffer_done() function;
308 * it is allways called after calling STREAMON ioctl;
309 * might be called before start_streaming callback if user
310 * pre-queued buffers before calling STREAMON.
313 int (*queue_setup
)(struct vb2_queue
*q
, const struct v4l2_format
*fmt
,
314 unsigned int *num_buffers
, unsigned int *num_planes
,
315 unsigned int sizes
[], void *alloc_ctxs
[]);
317 void (*wait_prepare
)(struct vb2_queue
*q
);
318 void (*wait_finish
)(struct vb2_queue
*q
);
320 int (*buf_init
)(struct vb2_buffer
*vb
);
321 int (*buf_prepare
)(struct vb2_buffer
*vb
);
322 void (*buf_finish
)(struct vb2_buffer
*vb
);
323 void (*buf_cleanup
)(struct vb2_buffer
*vb
);
325 int (*start_streaming
)(struct vb2_queue
*q
, unsigned int count
);
326 int (*stop_streaming
)(struct vb2_queue
*q
);
328 void (*buf_queue
)(struct vb2_buffer
*vb
);
334 * struct vb2_queue - a videobuf queue
336 * @type: queue type (see V4L2_BUF_TYPE_* in linux/videodev2.h
337 * @io_modes: supported io methods (see vb2_io_modes enum)
338 * @io_flags: additional io flags (see vb2_fileio_flags enum)
339 * @lock: pointer to a mutex that protects the vb2_queue struct. The
340 * driver can set this to a mutex to let the v4l2 core serialize
341 * the queuing ioctls. If the driver wants to handle locking
342 * itself, then this should be set to NULL. This lock is not used
343 * by the videobuf2 core API.
344 * @owner: The filehandle that 'owns' the buffers, i.e. the filehandle
345 * that called reqbufs, create_buffers or started fileio.
346 * This field is not used by the videobuf2 core API, but it allows
347 * drivers to easily associate an owner filehandle with the queue.
348 * @ops: driver-specific callbacks
349 * @mem_ops: memory allocator specific callbacks
350 * @drv_priv: driver private data
351 * @buf_struct_size: size of the driver-specific buffer structure;
352 * "0" indicates the driver doesn't want to use a custom buffer
353 * structure type, so sizeof(struct vb2_buffer) will is used
354 * @timestamp_flags: Timestamp flags; V4L2_BUF_FLAGS_TIMESTAMP_* and
355 * V4L2_BUF_FLAGS_TSTAMP_SRC_*
356 * @gfp_flags: additional gfp flags used when allocating the buffers.
357 * Typically this is 0, but it may be e.g. GFP_DMA or __GFP_DMA32
358 * to force the buffer allocation to a specific memory zone.
359 * @min_buffers_needed: the minimum number of buffers needed before
360 * start_streaming() can be called. Used when a DMA engine
361 * cannot be started unless at least this number of buffers
362 * have been queued into the driver.
364 * @memory: current memory type used
365 * @bufs: videobuf buffer structures
366 * @num_buffers: number of allocated/used buffers
367 * @queued_list: list of buffers currently queued from userspace
368 * @queued_count: number of buffers queued and ready for streaming.
369 * @owned_by_drv_count: number of buffers owned by the driver
370 * @done_list: list of buffers ready to be dequeued to userspace
371 * @done_lock: lock to protect done_list list
372 * @done_wq: waitqueue for processes waiting for buffers ready to be dequeued
373 * @alloc_ctx: memory type/allocator-specific contexts for each plane
374 * @streaming: current streaming state
375 * @start_streaming_called: start_streaming() was called successfully and we
377 * @fileio: file io emulator internal data, used only if emulator is active
380 enum v4l2_buf_type type
;
381 unsigned int io_modes
;
382 unsigned int io_flags
;
384 struct v4l2_fh
*owner
;
386 const struct vb2_ops
*ops
;
387 const struct vb2_mem_ops
*mem_ops
;
389 unsigned int buf_struct_size
;
392 u32 min_buffers_needed
;
394 /* private: internal use only */
395 enum v4l2_memory memory
;
396 struct vb2_buffer
*bufs
[VIDEO_MAX_FRAME
];
397 unsigned int num_buffers
;
399 struct list_head queued_list
;
400 unsigned int queued_count
;
402 atomic_t owned_by_drv_count
;
403 struct list_head done_list
;
404 spinlock_t done_lock
;
405 wait_queue_head_t done_wq
;
407 void *alloc_ctx
[VIDEO_MAX_PLANES
];
408 unsigned int plane_sizes
[VIDEO_MAX_PLANES
];
410 unsigned int streaming
:1;
411 unsigned int start_streaming_called
:1;
413 struct vb2_fileio_data
*fileio
;
415 #ifdef CONFIG_VIDEO_ADV_DEBUG
417 * Counters for how often these queue-related ops are
418 * called. Used to check for unbalanced ops.
421 u32 cnt_wait_prepare
;
423 u32 cnt_start_streaming
;
424 u32 cnt_stop_streaming
;
428 void *vb2_plane_vaddr(struct vb2_buffer
*vb
, unsigned int plane_no
);
429 void *vb2_plane_cookie(struct vb2_buffer
*vb
, unsigned int plane_no
);
431 void vb2_buffer_done(struct vb2_buffer
*vb
, enum vb2_buffer_state state
);
432 int vb2_wait_for_all_buffers(struct vb2_queue
*q
);
434 int vb2_querybuf(struct vb2_queue
*q
, struct v4l2_buffer
*b
);
435 int vb2_reqbufs(struct vb2_queue
*q
, struct v4l2_requestbuffers
*req
);
437 int vb2_create_bufs(struct vb2_queue
*q
, struct v4l2_create_buffers
*create
);
438 int vb2_prepare_buf(struct vb2_queue
*q
, struct v4l2_buffer
*b
);
440 int __must_check
vb2_queue_init(struct vb2_queue
*q
);
442 void vb2_queue_release(struct vb2_queue
*q
);
444 int vb2_qbuf(struct vb2_queue
*q
, struct v4l2_buffer
*b
);
445 int vb2_expbuf(struct vb2_queue
*q
, struct v4l2_exportbuffer
*eb
);
446 int vb2_dqbuf(struct vb2_queue
*q
, struct v4l2_buffer
*b
, bool nonblocking
);
448 int vb2_streamon(struct vb2_queue
*q
, enum v4l2_buf_type type
);
449 int vb2_streamoff(struct vb2_queue
*q
, enum v4l2_buf_type type
);
451 int vb2_mmap(struct vb2_queue
*q
, struct vm_area_struct
*vma
);
453 unsigned long vb2_get_unmapped_area(struct vb2_queue
*q
,
457 unsigned long flags
);
459 unsigned int vb2_poll(struct vb2_queue
*q
, struct file
*file
, poll_table
*wait
);
460 size_t vb2_read(struct vb2_queue
*q
, char __user
*data
, size_t count
,
461 loff_t
*ppos
, int nonblock
);
462 size_t vb2_write(struct vb2_queue
*q
, const char __user
*data
, size_t count
,
463 loff_t
*ppos
, int nonblock
);
466 * vb2_is_streaming() - return streaming status of the queue
469 static inline bool vb2_is_streaming(struct vb2_queue
*q
)
475 * vb2_is_busy() - return busy status of the queue
478 * This function checks if queue has any buffers allocated.
480 static inline bool vb2_is_busy(struct vb2_queue
*q
)
482 return (q
->num_buffers
> 0);
486 * vb2_get_drv_priv() - return driver private data associated with the queue
489 static inline void *vb2_get_drv_priv(struct vb2_queue
*q
)
495 * vb2_set_plane_payload() - set bytesused for the plane plane_no
496 * @vb: buffer for which plane payload should be set
497 * @plane_no: plane number for which payload should be set
498 * @size: payload in bytes
500 static inline void vb2_set_plane_payload(struct vb2_buffer
*vb
,
501 unsigned int plane_no
, unsigned long size
)
503 if (plane_no
< vb
->num_planes
)
504 vb
->v4l2_planes
[plane_no
].bytesused
= size
;
508 * vb2_get_plane_payload() - get bytesused for the plane plane_no
509 * @vb: buffer for which plane payload should be set
510 * @plane_no: plane number for which payload should be set
511 * @size: payload in bytes
513 static inline unsigned long vb2_get_plane_payload(struct vb2_buffer
*vb
,
514 unsigned int plane_no
)
516 if (plane_no
< vb
->num_planes
)
517 return vb
->v4l2_planes
[plane_no
].bytesused
;
522 * vb2_plane_size() - return plane size in bytes
523 * @vb: buffer for which plane size should be returned
524 * @plane_no: plane number for which size should be returned
526 static inline unsigned long
527 vb2_plane_size(struct vb2_buffer
*vb
, unsigned int plane_no
)
529 if (plane_no
< vb
->num_planes
)
530 return vb
->v4l2_planes
[plane_no
].length
;
535 * The following functions are not part of the vb2 core API, but are simple
536 * helper functions that you can use in your struct v4l2_file_operations,
537 * struct v4l2_ioctl_ops and struct vb2_ops. They will serialize if vb2_queue->lock
538 * or video_device->lock is set, and they will set and test vb2_queue->owner
539 * to check if the calling filehandle is permitted to do the queuing operation.
542 /* struct v4l2_ioctl_ops helpers */
544 int vb2_ioctl_reqbufs(struct file
*file
, void *priv
,
545 struct v4l2_requestbuffers
*p
);
546 int vb2_ioctl_create_bufs(struct file
*file
, void *priv
,
547 struct v4l2_create_buffers
*p
);
548 int vb2_ioctl_prepare_buf(struct file
*file
, void *priv
,
549 struct v4l2_buffer
*p
);
550 int vb2_ioctl_querybuf(struct file
*file
, void *priv
, struct v4l2_buffer
*p
);
551 int vb2_ioctl_qbuf(struct file
*file
, void *priv
, struct v4l2_buffer
*p
);
552 int vb2_ioctl_dqbuf(struct file
*file
, void *priv
, struct v4l2_buffer
*p
);
553 int vb2_ioctl_streamon(struct file
*file
, void *priv
, enum v4l2_buf_type i
);
554 int vb2_ioctl_streamoff(struct file
*file
, void *priv
, enum v4l2_buf_type i
);
555 int vb2_ioctl_expbuf(struct file
*file
, void *priv
,
556 struct v4l2_exportbuffer
*p
);
558 /* struct v4l2_file_operations helpers */
560 int vb2_fop_mmap(struct file
*file
, struct vm_area_struct
*vma
);
561 int vb2_fop_release(struct file
*file
);
562 int _vb2_fop_release(struct file
*file
, struct mutex
*lock
);
563 ssize_t
vb2_fop_write(struct file
*file
, const char __user
*buf
,
564 size_t count
, loff_t
*ppos
);
565 ssize_t
vb2_fop_read(struct file
*file
, char __user
*buf
,
566 size_t count
, loff_t
*ppos
);
567 unsigned int vb2_fop_poll(struct file
*file
, poll_table
*wait
);
569 unsigned long vb2_fop_get_unmapped_area(struct file
*file
, unsigned long addr
,
570 unsigned long len
, unsigned long pgoff
, unsigned long flags
);
573 /* struct vb2_ops helpers, only use if vq->lock is non-NULL. */
575 void vb2_ops_wait_prepare(struct vb2_queue
*vq
);
576 void vb2_ops_wait_finish(struct vb2_queue
*vq
);
578 #endif /* _MEDIA_VIDEOBUF2_CORE_H */