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
31 * @put: inform the allocator that the buffer will no longer be used;
32 * usually will result in the allocator freeing the buffer (if
33 * no other users of this buffer are present); the buf_priv
34 * argument is the allocator private per-buffer structure
35 * previously returned from the alloc callback
36 * @get_userptr: acquire userspace memory for a hardware operation; used for
37 * USERPTR memory types; vaddr is the address passed to the
38 * videobuf layer when queuing a video buffer of USERPTR type;
39 * should return an allocator private per-buffer structure
40 * associated with the buffer on success, NULL on failure;
41 * the returned private structure will then be passed as buf_priv
42 * argument to other ops in this structure
43 * @put_userptr: inform the allocator that a USERPTR buffer will no longer
45 * @attach_dmabuf: attach a shared struct dma_buf for a hardware operation;
46 * used for DMABUF memory types; alloc_ctx is the alloc context
47 * dbuf is the shared dma_buf; returns NULL on failure;
48 * allocator private per-buffer structure on success;
49 * this needs to be used for further accesses to the buffer
50 * @detach_dmabuf: inform the exporter of the buffer that the current DMABUF
51 * buffer is no longer used; the buf_priv argument is the
52 * allocator private per-buffer structure previously returned
53 * from the attach_dmabuf callback
54 * @map_dmabuf: request for access to the dmabuf from allocator; the allocator
55 * of dmabuf is informed that this driver is going to use the
57 * @unmap_dmabuf: releases access control to the dmabuf - allocator is notified
58 * that this driver is done using the dmabuf for now
59 * @prepare: called every time the buffer is passed from userspace to the
60 * driver, useful for cache synchronisation, optional
61 * @finish: called every time the buffer is passed back from the driver
62 * to the userspace, also optional
63 * @vaddr: return a kernel virtual address to a given memory buffer
64 * associated with the passed private structure or NULL if no
66 * @cookie: return allocator specific cookie for a given memory buffer
67 * associated with the passed private structure or NULL if not
69 * @num_users: return the current number of users of a memory buffer;
70 * return 1 if the videobuf layer (or actually the driver using
71 * it) is the only user
72 * @mmap: setup a userspace mapping for a given memory buffer under
73 * the provided virtual memory region
75 * Required ops for USERPTR types: get_userptr, put_userptr.
76 * Required ops for MMAP types: alloc, put, num_users, mmap.
77 * Required ops for read/write access types: alloc, put, num_users, vaddr
78 * Required ops for DMABUF types: attach_dmabuf, detach_dmabuf, map_dmabuf,
82 void *(*alloc
)(void *alloc_ctx
, unsigned long size
);
83 void (*put
)(void *buf_priv
);
85 void *(*get_userptr
)(void *alloc_ctx
, unsigned long vaddr
,
86 unsigned long size
, int write
);
87 void (*put_userptr
)(void *buf_priv
);
89 void (*prepare
)(void *buf_priv
);
90 void (*finish
)(void *buf_priv
);
92 void *(*attach_dmabuf
)(void *alloc_ctx
, struct dma_buf
*dbuf
,
93 unsigned long size
, int write
);
94 void (*detach_dmabuf
)(void *buf_priv
);
95 int (*map_dmabuf
)(void *buf_priv
);
96 void (*unmap_dmabuf
)(void *buf_priv
);
98 void *(*vaddr
)(void *buf_priv
);
99 void *(*cookie
)(void *buf_priv
);
101 unsigned int (*num_users
)(void *buf_priv
);
103 int (*mmap
)(void *buf_priv
, struct vm_area_struct
*vma
);
108 struct dma_buf
*dbuf
;
109 unsigned int dbuf_mapped
;
113 * enum vb2_io_modes - queue access methods
114 * @VB2_MMAP: driver supports MMAP with streaming API
115 * @VB2_USERPTR: driver supports USERPTR with streaming API
116 * @VB2_READ: driver supports read() style access
117 * @VB2_WRITE: driver supports write() style access
118 * @VB2_DMABUF: driver supports DMABUF with streaming API
122 VB2_USERPTR
= (1 << 1),
124 VB2_WRITE
= (1 << 3),
125 VB2_DMABUF
= (1 << 4),
129 * enum vb2_fileio_flags - flags for selecting a mode of the file io emulator,
130 * by default the 'streaming' style is used by the file io emulator
131 * @VB2_FILEIO_READ_ONCE: report EOF after reading the first buffer
132 * @VB2_FILEIO_WRITE_IMMEDIATELY: queue buffer after each write() call
134 enum vb2_fileio_flags
{
135 VB2_FILEIO_READ_ONCE
= (1 << 0),
136 VB2_FILEIO_WRITE_IMMEDIATELY
= (1 << 1),
140 * enum vb2_buffer_state - current video buffer state
141 * @VB2_BUF_STATE_DEQUEUED: buffer under userspace control
142 * @VB2_BUF_STATE_PREPARED: buffer prepared in videobuf and by the driver
143 * @VB2_BUF_STATE_QUEUED: buffer queued in videobuf, but not in driver
144 * @VB2_BUF_STATE_ACTIVE: buffer queued in driver and possibly used
145 * in a hardware operation
146 * @VB2_BUF_STATE_DONE: buffer returned from driver to videobuf, but
147 * not yet dequeued to userspace
148 * @VB2_BUF_STATE_ERROR: same as above, but the operation on the buffer
149 * has ended with an error, which will be reported
150 * to the userspace when it is dequeued
152 enum vb2_buffer_state
{
153 VB2_BUF_STATE_DEQUEUED
,
154 VB2_BUF_STATE_PREPARED
,
155 VB2_BUF_STATE_QUEUED
,
156 VB2_BUF_STATE_ACTIVE
,
164 * struct vb2_buffer - represents a video buffer
165 * @v4l2_buf: struct v4l2_buffer associated with this buffer; can
166 * be read by the driver and relevant entries can be
167 * changed by the driver in case of CAPTURE types
168 * (such as timestamp)
169 * @v4l2_planes: struct v4l2_planes associated with this buffer; can
170 * be read by the driver and relevant entries can be
171 * changed by the driver in case of CAPTURE types
172 * (such as bytesused); NOTE that even for single-planar
173 * types, the v4l2_planes[0] struct should be used
174 * instead of v4l2_buf for filling bytesused - drivers
175 * should use the vb2_set_plane_payload() function for that
176 * @vb2_queue: the queue to which this driver belongs
177 * @num_planes: number of planes in the buffer
178 * on an internal driver queue
179 * @state: current buffer state; do not change
180 * @queued_entry: entry on the queued buffers list, which holds all
181 * buffers queued from userspace
182 * @done_entry: entry on the list that stores all buffers ready to
183 * be dequeued to userspace
184 * @planes: private per-plane information; do not change
187 struct v4l2_buffer v4l2_buf
;
188 struct v4l2_plane v4l2_planes
[VIDEO_MAX_PLANES
];
190 struct vb2_queue
*vb2_queue
;
192 unsigned int num_planes
;
194 /* Private: internal use only */
195 enum vb2_buffer_state state
;
197 struct list_head queued_entry
;
198 struct list_head done_entry
;
200 struct vb2_plane planes
[VIDEO_MAX_PLANES
];
204 * struct vb2_ops - driver-specific callbacks
206 * @queue_setup: called from VIDIOC_REQBUFS and VIDIOC_CREATE_BUFS
207 * handlers before memory allocation, or, if
208 * *num_planes != 0, after the allocation to verify a
209 * smaller number of buffers. Driver should return
210 * the required number of buffers in *num_buffers, the
211 * required number of planes per buffer in *num_planes; the
212 * size of each plane should be set in the sizes[] array
213 * and optional per-plane allocator specific context in the
214 * alloc_ctxs[] array. When called from VIDIOC_REQBUFS,
215 * fmt == NULL, the driver has to use the currently
216 * configured format and *num_buffers is the total number
217 * of buffers, that are being allocated. When called from
218 * VIDIOC_CREATE_BUFS, fmt != NULL and it describes the
219 * target frame format. In this case *num_buffers are being
220 * allocated additionally to q->num_buffers.
221 * @wait_prepare: release any locks taken while calling vb2 functions;
222 * it is called before an ioctl needs to wait for a new
223 * buffer to arrive; required to avoid a deadlock in
224 * blocking access type
225 * @wait_finish: reacquire all locks released in the previous callback;
226 * required to continue operation after sleeping while
227 * waiting for a new buffer to arrive
228 * @buf_init: called once after allocating a buffer (in MMAP case)
229 * or after acquiring a new USERPTR buffer; drivers may
230 * perform additional buffer-related initialization;
231 * initialization failure (return != 0) will prevent
232 * queue setup from completing successfully; optional
233 * @buf_prepare: called every time the buffer is queued from userspace
234 * and from the VIDIOC_PREPARE_BUF ioctl; drivers may
235 * perform any initialization required before each hardware
236 * operation in this callback; if an error is returned, the
237 * buffer will not be queued in driver; optional
238 * @buf_finish: called before every dequeue of the buffer back to
239 * userspace; drivers may perform any operations required
240 * before userspace accesses the buffer; optional
241 * @buf_cleanup: called once before the buffer is freed; drivers may
242 * perform any additional cleanup; optional
243 * @start_streaming: called once to enter 'streaming' state; the driver may
244 * receive buffers with @buf_queue callback before
245 * @start_streaming is called; the driver gets the number
246 * of already queued buffers in count parameter; driver
247 * can return an error if hardware fails or not enough
248 * buffers has been queued, in such case all buffers that
249 * have been already given by the @buf_queue callback are
251 * @stop_streaming: called when 'streaming' state must be disabled; driver
252 * should stop any DMA transactions or wait until they
253 * finish and give back all buffers it got from buf_queue()
254 * callback; may use vb2_wait_for_all_buffers() function
255 * @buf_queue: passes buffer vb to the driver; driver may start
256 * hardware operation on this buffer; driver should give
257 * the buffer back by calling vb2_buffer_done() function;
258 * it is allways called after calling STREAMON ioctl;
259 * might be called before start_streaming callback if user
260 * pre-queued buffers before calling STREAMON
263 int (*queue_setup
)(struct vb2_queue
*q
, const struct v4l2_format
*fmt
,
264 unsigned int *num_buffers
, unsigned int *num_planes
,
265 unsigned int sizes
[], void *alloc_ctxs
[]);
267 void (*wait_prepare
)(struct vb2_queue
*q
);
268 void (*wait_finish
)(struct vb2_queue
*q
);
270 int (*buf_init
)(struct vb2_buffer
*vb
);
271 int (*buf_prepare
)(struct vb2_buffer
*vb
);
272 int (*buf_finish
)(struct vb2_buffer
*vb
);
273 void (*buf_cleanup
)(struct vb2_buffer
*vb
);
275 int (*start_streaming
)(struct vb2_queue
*q
, unsigned int count
);
276 int (*stop_streaming
)(struct vb2_queue
*q
);
278 void (*buf_queue
)(struct vb2_buffer
*vb
);
284 * struct vb2_queue - a videobuf queue
286 * @type: queue type (see V4L2_BUF_TYPE_* in linux/videodev2.h
287 * @io_modes: supported io methods (see vb2_io_modes enum)
288 * @io_flags: additional io flags (see vb2_fileio_flags enum)
289 * @lock: pointer to a mutex that protects the vb2_queue struct. The
290 * driver can set this to a mutex to let the v4l2 core serialize
291 * the queuing ioctls. If the driver wants to handle locking
292 * itself, then this should be set to NULL. This lock is not used
293 * by the videobuf2 core API.
294 * @owner: The filehandle that 'owns' the buffers, i.e. the filehandle
295 * that called reqbufs, create_buffers or started fileio.
296 * This field is not used by the videobuf2 core API, but it allows
297 * drivers to easily associate an owner filehandle with the queue.
298 * @ops: driver-specific callbacks
299 * @mem_ops: memory allocator specific callbacks
300 * @drv_priv: driver private data
301 * @buf_struct_size: size of the driver-specific buffer structure;
302 * "0" indicates the driver doesn't want to use a custom buffer
303 * structure type, so sizeof(struct vb2_buffer) will is used
305 * @memory: current memory type used
306 * @bufs: videobuf buffer structures
307 * @num_buffers: number of allocated/used buffers
308 * @queued_list: list of buffers currently queued from userspace
309 * @queued_count: number of buffers owned by the driver
310 * @done_list: list of buffers ready to be dequeued to userspace
311 * @done_lock: lock to protect done_list list
312 * @done_wq: waitqueue for processes waiting for buffers ready to be dequeued
313 * @alloc_ctx: memory type/allocator-specific contexts for each plane
314 * @streaming: current streaming state
315 * @fileio: file io emulator internal data, used only if emulator is active
318 enum v4l2_buf_type type
;
319 unsigned int io_modes
;
320 unsigned int io_flags
;
322 struct v4l2_fh
*owner
;
324 const struct vb2_ops
*ops
;
325 const struct vb2_mem_ops
*mem_ops
;
327 unsigned int buf_struct_size
;
329 /* private: internal use only */
330 enum v4l2_memory memory
;
331 struct vb2_buffer
*bufs
[VIDEO_MAX_FRAME
];
332 unsigned int num_buffers
;
334 struct list_head queued_list
;
336 atomic_t queued_count
;
337 struct list_head done_list
;
338 spinlock_t done_lock
;
339 wait_queue_head_t done_wq
;
341 void *alloc_ctx
[VIDEO_MAX_PLANES
];
342 unsigned int plane_sizes
[VIDEO_MAX_PLANES
];
344 unsigned int streaming
:1;
346 struct vb2_fileio_data
*fileio
;
349 void *vb2_plane_vaddr(struct vb2_buffer
*vb
, unsigned int plane_no
);
350 void *vb2_plane_cookie(struct vb2_buffer
*vb
, unsigned int plane_no
);
352 void vb2_buffer_done(struct vb2_buffer
*vb
, enum vb2_buffer_state state
);
353 int vb2_wait_for_all_buffers(struct vb2_queue
*q
);
355 int vb2_querybuf(struct vb2_queue
*q
, struct v4l2_buffer
*b
);
356 int vb2_reqbufs(struct vb2_queue
*q
, struct v4l2_requestbuffers
*req
);
358 int vb2_create_bufs(struct vb2_queue
*q
, struct v4l2_create_buffers
*create
);
359 int vb2_prepare_buf(struct vb2_queue
*q
, struct v4l2_buffer
*b
);
361 int __must_check
vb2_queue_init(struct vb2_queue
*q
);
363 void vb2_queue_release(struct vb2_queue
*q
);
365 int vb2_qbuf(struct vb2_queue
*q
, struct v4l2_buffer
*b
);
366 int vb2_dqbuf(struct vb2_queue
*q
, struct v4l2_buffer
*b
, bool nonblocking
);
368 int vb2_streamon(struct vb2_queue
*q
, enum v4l2_buf_type type
);
369 int vb2_streamoff(struct vb2_queue
*q
, enum v4l2_buf_type type
);
371 int vb2_mmap(struct vb2_queue
*q
, struct vm_area_struct
*vma
);
373 unsigned long vb2_get_unmapped_area(struct vb2_queue
*q
,
377 unsigned long flags
);
379 unsigned int vb2_poll(struct vb2_queue
*q
, struct file
*file
, poll_table
*wait
);
380 size_t vb2_read(struct vb2_queue
*q
, char __user
*data
, size_t count
,
381 loff_t
*ppos
, int nonblock
);
382 size_t vb2_write(struct vb2_queue
*q
, char __user
*data
, size_t count
,
383 loff_t
*ppos
, int nonblock
);
386 * vb2_is_streaming() - return streaming status of the queue
389 static inline bool vb2_is_streaming(struct vb2_queue
*q
)
395 * vb2_is_busy() - return busy status of the queue
398 * This function checks if queue has any buffers allocated.
400 static inline bool vb2_is_busy(struct vb2_queue
*q
)
402 return (q
->num_buffers
> 0);
406 * vb2_get_drv_priv() - return driver private data associated with the queue
409 static inline void *vb2_get_drv_priv(struct vb2_queue
*q
)
415 * vb2_set_plane_payload() - set bytesused for the plane plane_no
416 * @vb: buffer for which plane payload should be set
417 * @plane_no: plane number for which payload should be set
418 * @size: payload in bytes
420 static inline void vb2_set_plane_payload(struct vb2_buffer
*vb
,
421 unsigned int plane_no
, unsigned long size
)
423 if (plane_no
< vb
->num_planes
)
424 vb
->v4l2_planes
[plane_no
].bytesused
= size
;
428 * vb2_get_plane_payload() - get bytesused for the plane plane_no
429 * @vb: buffer for which plane payload should be set
430 * @plane_no: plane number for which payload should be set
431 * @size: payload in bytes
433 static inline unsigned long vb2_get_plane_payload(struct vb2_buffer
*vb
,
434 unsigned int plane_no
)
436 if (plane_no
< vb
->num_planes
)
437 return vb
->v4l2_planes
[plane_no
].bytesused
;
442 * vb2_plane_size() - return plane size in bytes
443 * @vb: buffer for which plane size should be returned
444 * @plane_no: plane number for which size should be returned
446 static inline unsigned long
447 vb2_plane_size(struct vb2_buffer
*vb
, unsigned int plane_no
)
449 if (plane_no
< vb
->num_planes
)
450 return vb
->v4l2_planes
[plane_no
].length
;
455 * The following functions are not part of the vb2 core API, but are simple
456 * helper functions that you can use in your struct v4l2_file_operations,
457 * struct v4l2_ioctl_ops and struct vb2_ops. They will serialize if vb2_queue->lock
458 * or video_device->lock is set, and they will set and test vb2_queue->owner
459 * to check if the calling filehandle is permitted to do the queuing operation.
462 /* struct v4l2_ioctl_ops helpers */
464 int vb2_ioctl_reqbufs(struct file
*file
, void *priv
,
465 struct v4l2_requestbuffers
*p
);
466 int vb2_ioctl_create_bufs(struct file
*file
, void *priv
,
467 struct v4l2_create_buffers
*p
);
468 int vb2_ioctl_prepare_buf(struct file
*file
, void *priv
,
469 struct v4l2_buffer
*p
);
470 int vb2_ioctl_querybuf(struct file
*file
, void *priv
, struct v4l2_buffer
*p
);
471 int vb2_ioctl_qbuf(struct file
*file
, void *priv
, struct v4l2_buffer
*p
);
472 int vb2_ioctl_dqbuf(struct file
*file
, void *priv
, struct v4l2_buffer
*p
);
473 int vb2_ioctl_streamon(struct file
*file
, void *priv
, enum v4l2_buf_type i
);
474 int vb2_ioctl_streamoff(struct file
*file
, void *priv
, enum v4l2_buf_type i
);
476 /* struct v4l2_file_operations helpers */
478 int vb2_fop_mmap(struct file
*file
, struct vm_area_struct
*vma
);
479 int vb2_fop_release(struct file
*file
);
480 ssize_t
vb2_fop_write(struct file
*file
, char __user
*buf
,
481 size_t count
, loff_t
*ppos
);
482 ssize_t
vb2_fop_read(struct file
*file
, char __user
*buf
,
483 size_t count
, loff_t
*ppos
);
484 unsigned int vb2_fop_poll(struct file
*file
, poll_table
*wait
);
486 unsigned long vb2_fop_get_unmapped_area(struct file
*file
, unsigned long addr
,
487 unsigned long len
, unsigned long pgoff
, unsigned long flags
);
490 /* struct vb2_ops helpers, only use if vq->lock is non-NULL. */
492 void vb2_ops_wait_prepare(struct vb2_queue
*vq
);
493 void vb2_ops_wait_finish(struct vb2_queue
*vq
);
495 #endif /* _MEDIA_VIDEOBUF2_CORE_H */