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1 : : /*
2 : : * videobuf2-core.h - Video Buffer 2 Core Framework
3 : : *
4 : : * Copyright (C) 2010 Samsung Electronics
5 : : *
6 : : * Author: Pawel Osciak <pawel@osciak.com>
7 : : *
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.
11 : : */
12 : : #ifndef _MEDIA_VIDEOBUF2_CORE_H
13 : : #define _MEDIA_VIDEOBUF2_CORE_H
14 : :
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>
21 : :
22 : : #define VB2_MAX_FRAME (32)
23 : : #define VB2_MAX_PLANES (8)
24 : :
25 : : /**
26 : : * enum vb2_memory - type of memory model used to make the buffers visible
27 : : * on userspace.
28 : : *
29 : : * @VB2_MEMORY_UNKNOWN: Buffer status is unknown or it is not used yet on
30 : : * userspace.
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.
38 : : */
39 : : enum vb2_memory {
40 : : VB2_MEMORY_UNKNOWN = 0,
41 : : VB2_MEMORY_MMAP = 1,
42 : : VB2_MEMORY_USERPTR = 2,
43 : : VB2_MEMORY_DMABUF = 4,
44 : : };
45 : :
46 : : struct vb2_fileio_data;
47 : : struct vb2_threadio_data;
48 : :
49 : : /**
50 : : * struct vb2_mem_ops - memory handling/memory allocator operations.
51 : : * @alloc: allocate video memory and, optionally, allocator private data,
52 : : * return ERR_PTR() on failure or a pointer to allocator private,
53 : : * per-buffer data on success; the returned private structure
54 : : * will then be passed as @buf_priv argument to other ops in this
55 : : * structure. Additional gfp_flags to use when allocating the
56 : : * are also passed to this operation. These flags are from the
57 : : * gfp_flags field of vb2_queue. The size argument to this function
58 : : * shall be *page aligned*.
59 : : * @put: inform the allocator that the buffer will no longer be used;
60 : : * usually will result in the allocator freeing the buffer (if
61 : : * no other users of this buffer are present); the @buf_priv
62 : : * argument is the allocator private per-buffer structure
63 : : * previously returned from the alloc callback.
64 : : * @get_dmabuf: acquire userspace memory for a hardware operation; used for
65 : : * DMABUF memory types.
66 : : * @get_userptr: acquire userspace memory for a hardware operation; used for
67 : : * USERPTR memory types; vaddr is the address passed to the
68 : : * videobuf layer when queuing a video buffer of USERPTR type;
69 : : * should return an allocator private per-buffer structure
70 : : * associated with the buffer on success, ERR_PTR() on failure;
71 : : * the returned private structure will then be passed as @buf_priv
72 : : * argument to other ops in this structure.
73 : : * @put_userptr: inform the allocator that a USERPTR buffer will no longer
74 : : * be used.
75 : : * @attach_dmabuf: attach a shared &struct dma_buf for a hardware operation;
76 : : * used for DMABUF memory types; dev is the alloc device
77 : : * dbuf is the shared dma_buf; returns ERR_PTR() on failure;
78 : : * allocator private per-buffer structure on success;
79 : : * this needs to be used for further accesses to the buffer.
80 : : * @detach_dmabuf: inform the exporter of the buffer that the current DMABUF
81 : : * buffer is no longer used; the @buf_priv argument is the
82 : : * allocator private per-buffer structure previously returned
83 : : * from the attach_dmabuf callback.
84 : : * @map_dmabuf: request for access to the dmabuf from allocator; the allocator
85 : : * of dmabuf is informed that this driver is going to use the
86 : : * dmabuf.
87 : : * @unmap_dmabuf: releases access control to the dmabuf - allocator is notified
88 : : * that this driver is done using the dmabuf for now.
89 : : * @prepare: called every time the buffer is passed from userspace to the
90 : : * driver, useful for cache synchronisation, optional.
91 : : * @finish: called every time the buffer is passed back from the driver
92 : : * to the userspace, also optional.
93 : : * @vaddr: return a kernel virtual address to a given memory buffer
94 : : * associated with the passed private structure or NULL if no
95 : : * such mapping exists.
96 : : * @cookie: return allocator specific cookie for a given memory buffer
97 : : * associated with the passed private structure or NULL if not
98 : : * available.
99 : : * @num_users: return the current number of users of a memory buffer;
100 : : * return 1 if the videobuf layer (or actually the driver using
101 : : * it) is the only user.
102 : : * @mmap: setup a userspace mapping for a given memory buffer under
103 : : * the provided virtual memory region.
104 : : *
105 : : * Those operations are used by the videobuf2 core to implement the memory
106 : : * handling/memory allocators for each type of supported streaming I/O method.
107 : : *
108 : : * .. note::
109 : : * #) Required ops for USERPTR types: get_userptr, put_userptr.
110 : : *
111 : : * #) Required ops for MMAP types: alloc, put, num_users, mmap.
112 : : *
113 : : * #) Required ops for read/write access types: alloc, put, num_users, vaddr.
114 : : *
115 : : * #) Required ops for DMABUF types: attach_dmabuf, detach_dmabuf,
116 : : * map_dmabuf, unmap_dmabuf.
117 : : */
118 : : struct vb2_mem_ops {
119 : : void *(*alloc)(struct device *dev, unsigned long attrs,
120 : : unsigned long size,
121 : : enum dma_data_direction dma_dir,
122 : : gfp_t gfp_flags);
123 : : void (*put)(void *buf_priv);
124 : : struct dma_buf *(*get_dmabuf)(void *buf_priv, unsigned long flags);
125 : :
126 : : void *(*get_userptr)(struct device *dev, unsigned long vaddr,
127 : : unsigned long size,
128 : : enum dma_data_direction dma_dir);
129 : : void (*put_userptr)(void *buf_priv);
130 : :
131 : : void (*prepare)(void *buf_priv);
132 : : void (*finish)(void *buf_priv);
133 : :
134 : : void *(*attach_dmabuf)(struct device *dev,
135 : : struct dma_buf *dbuf,
136 : : unsigned long size,
137 : : enum dma_data_direction dma_dir);
138 : : void (*detach_dmabuf)(void *buf_priv);
139 : : int (*map_dmabuf)(void *buf_priv);
140 : : void (*unmap_dmabuf)(void *buf_priv);
141 : :
142 : : void *(*vaddr)(void *buf_priv);
143 : : void *(*cookie)(void *buf_priv);
144 : :
145 : : unsigned int (*num_users)(void *buf_priv);
146 : :
147 : : int (*mmap)(void *buf_priv, struct vm_area_struct *vma);
148 : : };
149 : :
150 : : /**
151 : : * struct vb2_plane - plane information.
152 : : * @mem_priv: private data with this plane.
153 : : * @dbuf: dma_buf - shared buffer object.
154 : : * @dbuf_mapped: flag to show whether dbuf is mapped or not
155 : : * @bytesused: number of bytes occupied by data in the plane (payload).
156 : : * @length: size of this plane (NOT the payload) in bytes.
157 : : * @min_length: minimum required size of this plane (NOT the payload) in bytes.
158 : : * @length is always greater or equal to @min_length.
159 : : * @m: Union with memtype-specific data.
160 : : * @m.offset: when memory in the associated struct vb2_buffer is
161 : : * %VB2_MEMORY_MMAP, equals the offset from the start of
162 : : * the device memory for this plane (or is a "cookie" that
163 : : * should be passed to mmap() called on the video node).
164 : : * @m.userptr: when memory is %VB2_MEMORY_USERPTR, a userspace pointer
165 : : * pointing to this plane.
166 : : * @m.fd: when memory is %VB2_MEMORY_DMABUF, a userspace file
167 : : * descriptor associated with this plane.
168 : : * @data_offset: offset in the plane to the start of data; usually 0,
169 : : * unless there is a header in front of the data.
170 : : *
171 : : * Should contain enough information to be able to cover all the fields
172 : : * of &struct v4l2_plane at videodev2.h.
173 : : */
174 : : struct vb2_plane {
175 : : void *mem_priv;
176 : : struct dma_buf *dbuf;
177 : : unsigned int dbuf_mapped;
178 : : unsigned int bytesused;
179 : : unsigned int length;
180 : : unsigned int min_length;
181 : : union {
182 : : unsigned int offset;
183 : : unsigned long userptr;
184 : : int fd;
185 : : } m;
186 : : unsigned int data_offset;
187 : : };
188 : :
189 : : /**
190 : : * enum vb2_io_modes - queue access methods.
191 : : * @VB2_MMAP: driver supports MMAP with streaming API.
192 : : * @VB2_USERPTR: driver supports USERPTR with streaming API.
193 : : * @VB2_READ: driver supports read() style access.
194 : : * @VB2_WRITE: driver supports write() style access.
195 : : * @VB2_DMABUF: driver supports DMABUF with streaming API.
196 : : */
197 : : enum vb2_io_modes {
198 : : VB2_MMAP = BIT(0),
199 : : VB2_USERPTR = BIT(1),
200 : : VB2_READ = BIT(2),
201 : : VB2_WRITE = BIT(3),
202 : : VB2_DMABUF = BIT(4),
203 : : };
204 : :
205 : : /**
206 : : * enum vb2_buffer_state - current video buffer state.
207 : : * @VB2_BUF_STATE_DEQUEUED: buffer under userspace control.
208 : : * @VB2_BUF_STATE_IN_REQUEST: buffer is queued in media request.
209 : : * @VB2_BUF_STATE_PREPARING: buffer is being prepared in videobuf.
210 : : * @VB2_BUF_STATE_QUEUED: buffer queued in videobuf, but not in driver.
211 : : * @VB2_BUF_STATE_ACTIVE: buffer queued in driver and possibly used
212 : : * in a hardware operation.
213 : : * @VB2_BUF_STATE_DONE: buffer returned from driver to videobuf, but
214 : : * not yet dequeued to userspace.
215 : : * @VB2_BUF_STATE_ERROR: same as above, but the operation on the buffer
216 : : * has ended with an error, which will be reported
217 : : * to the userspace when it is dequeued.
218 : : */
219 : : enum vb2_buffer_state {
220 : : VB2_BUF_STATE_DEQUEUED,
221 : : VB2_BUF_STATE_IN_REQUEST,
222 : : VB2_BUF_STATE_PREPARING,
223 : : VB2_BUF_STATE_QUEUED,
224 : : VB2_BUF_STATE_ACTIVE,
225 : : VB2_BUF_STATE_DONE,
226 : : VB2_BUF_STATE_ERROR,
227 : : };
228 : :
229 : : struct vb2_queue;
230 : :
231 : : /**
232 : : * struct vb2_buffer - represents a video buffer.
233 : : * @vb2_queue: pointer to &struct vb2_queue with the queue to
234 : : * which this driver belongs.
235 : : * @index: id number of the buffer.
236 : : * @type: buffer type.
237 : : * @memory: the method, in which the actual data is passed.
238 : : * @num_planes: number of planes in the buffer
239 : : * on an internal driver queue.
240 : : * @timestamp: frame timestamp in ns.
241 : : * @request: the request this buffer is associated with.
242 : : * @req_obj: used to bind this buffer to a request. This
243 : : * request object has a refcount.
244 : : */
245 : : struct vb2_buffer {
246 : : struct vb2_queue *vb2_queue;
247 : : unsigned int index;
248 : : unsigned int type;
249 : : unsigned int memory;
250 : : unsigned int num_planes;
251 : : u64 timestamp;
252 : : struct media_request *request;
253 : : struct media_request_object req_obj;
254 : :
255 : : /* private: internal use only
256 : : *
257 : : * state: current buffer state; do not change
258 : : * synced: this buffer has been synced for DMA, i.e. the
259 : : * 'prepare' memop was called. It is cleared again
260 : : * after the 'finish' memop is called.
261 : : * prepared: this buffer has been prepared, i.e. the
262 : : * buf_prepare op was called. It is cleared again
263 : : * after the 'buf_finish' op is called.
264 : : * copied_timestamp: the timestamp of this capture buffer was copied
265 : : * from an output buffer.
266 : : * queued_entry: entry on the queued buffers list, which holds
267 : : * all buffers queued from userspace
268 : : * done_entry: entry on the list that stores all buffers ready
269 : : * to be dequeued to userspace
270 : : * vb2_plane: per-plane information; do not change
271 : : */
272 : : enum vb2_buffer_state state;
273 : : unsigned int synced:1;
274 : : unsigned int prepared:1;
275 : : unsigned int copied_timestamp:1;
276 : :
277 : : struct vb2_plane planes[VB2_MAX_PLANES];
278 : : struct list_head queued_entry;
279 : : struct list_head done_entry;
280 : : #ifdef CONFIG_VIDEO_ADV_DEBUG
281 : : /*
282 : : * Counters for how often these buffer-related ops are
283 : : * called. Used to check for unbalanced ops.
284 : : */
285 : : u32 cnt_mem_alloc;
286 : : u32 cnt_mem_put;
287 : : u32 cnt_mem_get_dmabuf;
288 : : u32 cnt_mem_get_userptr;
289 : : u32 cnt_mem_put_userptr;
290 : : u32 cnt_mem_prepare;
291 : : u32 cnt_mem_finish;
292 : : u32 cnt_mem_attach_dmabuf;
293 : : u32 cnt_mem_detach_dmabuf;
294 : : u32 cnt_mem_map_dmabuf;
295 : : u32 cnt_mem_unmap_dmabuf;
296 : : u32 cnt_mem_vaddr;
297 : : u32 cnt_mem_cookie;
298 : : u32 cnt_mem_num_users;
299 : : u32 cnt_mem_mmap;
300 : :
301 : : u32 cnt_buf_out_validate;
302 : : u32 cnt_buf_init;
303 : : u32 cnt_buf_prepare;
304 : : u32 cnt_buf_finish;
305 : : u32 cnt_buf_cleanup;
306 : : u32 cnt_buf_queue;
307 : : u32 cnt_buf_request_complete;
308 : :
309 : : /* This counts the number of calls to vb2_buffer_done() */
310 : : u32 cnt_buf_done;
311 : : #endif
312 : : };
313 : :
314 : : /**
315 : : * struct vb2_ops - driver-specific callbacks.
316 : : *
317 : : * These operations are not called from interrupt context except where
318 : : * mentioned specifically.
319 : : *
320 : : * @queue_setup: called from VIDIOC_REQBUFS() and VIDIOC_CREATE_BUFS()
321 : : * handlers before memory allocation. It can be called
322 : : * twice: if the original number of requested buffers
323 : : * could not be allocated, then it will be called a
324 : : * second time with the actually allocated number of
325 : : * buffers to verify if that is OK.
326 : : * The driver should return the required number of buffers
327 : : * in \*num_buffers, the required number of planes per
328 : : * buffer in \*num_planes, the size of each plane should be
329 : : * set in the sizes\[\] array and optional per-plane
330 : : * allocator specific device in the alloc_devs\[\] array.
331 : : * When called from VIDIOC_REQBUFS(), \*num_planes == 0,
332 : : * the driver has to use the currently configured format to
333 : : * determine the plane sizes and \*num_buffers is the total
334 : : * number of buffers that are being allocated. When called
335 : : * from VIDIOC_CREATE_BUFS(), \*num_planes != 0 and it
336 : : * describes the requested number of planes and sizes\[\]
337 : : * contains the requested plane sizes. In this case
338 : : * \*num_buffers are being allocated additionally to
339 : : * q->num_buffers. If either \*num_planes or the requested
340 : : * sizes are invalid callback must return %-EINVAL.
341 : : * @wait_prepare: release any locks taken while calling vb2 functions;
342 : : * it is called before an ioctl needs to wait for a new
343 : : * buffer to arrive; required to avoid a deadlock in
344 : : * blocking access type.
345 : : * @wait_finish: reacquire all locks released in the previous callback;
346 : : * required to continue operation after sleeping while
347 : : * waiting for a new buffer to arrive.
348 : : * @buf_out_validate: called when the output buffer is prepared or queued
349 : : * to a request; drivers can use this to validate
350 : : * userspace-provided information; this is required only
351 : : * for OUTPUT queues.
352 : : * @buf_init: called once after allocating a buffer (in MMAP case)
353 : : * or after acquiring a new USERPTR buffer; drivers may
354 : : * perform additional buffer-related initialization;
355 : : * initialization failure (return != 0) will prevent
356 : : * queue setup from completing successfully; optional.
357 : : * @buf_prepare: called every time the buffer is queued from userspace
358 : : * and from the VIDIOC_PREPARE_BUF() ioctl; drivers may
359 : : * perform any initialization required before each
360 : : * hardware operation in this callback; drivers can
361 : : * access/modify the buffer here as it is still synced for
362 : : * the CPU; drivers that support VIDIOC_CREATE_BUFS() must
363 : : * also validate the buffer size; if an error is returned,
364 : : * the buffer will not be queued in driver; optional.
365 : : * @buf_finish: called before every dequeue of the buffer back to
366 : : * userspace; the buffer is synced for the CPU, so drivers
367 : : * can access/modify the buffer contents; drivers may
368 : : * perform any operations required before userspace
369 : : * accesses the buffer; optional. The buffer state can be
370 : : * one of the following: %DONE and %ERROR occur while
371 : : * streaming is in progress, and the %PREPARED state occurs
372 : : * when the queue has been canceled and all pending
373 : : * buffers are being returned to their default %DEQUEUED
374 : : * state. Typically you only have to do something if the
375 : : * state is %VB2_BUF_STATE_DONE, since in all other cases
376 : : * the buffer contents will be ignored anyway.
377 : : * @buf_cleanup: called once before the buffer is freed; drivers may
378 : : * perform any additional cleanup; optional.
379 : : * @start_streaming: called once to enter 'streaming' state; the driver may
380 : : * receive buffers with @buf_queue callback
381 : : * before @start_streaming is called; the driver gets the
382 : : * number of already queued buffers in count parameter;
383 : : * driver can return an error if hardware fails, in that
384 : : * case all buffers that have been already given by
385 : : * the @buf_queue callback are to be returned by the driver
386 : : * by calling vb2_buffer_done() with %VB2_BUF_STATE_QUEUED.
387 : : * If you need a minimum number of buffers before you can
388 : : * start streaming, then set
389 : : * &vb2_queue->min_buffers_needed. If that is non-zero
390 : : * then @start_streaming won't be called until at least
391 : : * that many buffers have been queued up by userspace.
392 : : * @stop_streaming: called when 'streaming' state must be disabled; driver
393 : : * should stop any DMA transactions or wait until they
394 : : * finish and give back all buffers it got from &buf_queue
395 : : * callback by calling vb2_buffer_done() with either
396 : : * %VB2_BUF_STATE_DONE or %VB2_BUF_STATE_ERROR; may use
397 : : * vb2_wait_for_all_buffers() function
398 : : * @buf_queue: passes buffer vb to the driver; driver may start
399 : : * hardware operation on this buffer; driver should give
400 : : * the buffer back by calling vb2_buffer_done() function;
401 : : * it is always called after calling VIDIOC_STREAMON()
402 : : * ioctl; might be called before @start_streaming callback
403 : : * if user pre-queued buffers before calling
404 : : * VIDIOC_STREAMON().
405 : : * @buf_request_complete: a buffer that was never queued to the driver but is
406 : : * associated with a queued request was canceled.
407 : : * The driver will have to mark associated objects in the
408 : : * request as completed; required if requests are
409 : : * supported.
410 : : */
411 : : struct vb2_ops {
412 : : int (*queue_setup)(struct vb2_queue *q,
413 : : unsigned int *num_buffers, unsigned int *num_planes,
414 : : unsigned int sizes[], struct device *alloc_devs[]);
415 : :
416 : : void (*wait_prepare)(struct vb2_queue *q);
417 : : void (*wait_finish)(struct vb2_queue *q);
418 : :
419 : : int (*buf_out_validate)(struct vb2_buffer *vb);
420 : : int (*buf_init)(struct vb2_buffer *vb);
421 : : int (*buf_prepare)(struct vb2_buffer *vb);
422 : : void (*buf_finish)(struct vb2_buffer *vb);
423 : : void (*buf_cleanup)(struct vb2_buffer *vb);
424 : :
425 : : int (*start_streaming)(struct vb2_queue *q, unsigned int count);
426 : : void (*stop_streaming)(struct vb2_queue *q);
427 : :
428 : : void (*buf_queue)(struct vb2_buffer *vb);
429 : :
430 : : void (*buf_request_complete)(struct vb2_buffer *vb);
431 : : };
432 : :
433 : : /**
434 : : * struct vb2_buf_ops - driver-specific callbacks.
435 : : *
436 : : * @verify_planes_array: Verify that a given user space structure contains
437 : : * enough planes for the buffer. This is called
438 : : * for each dequeued buffer.
439 : : * @init_buffer: given a &vb2_buffer initialize the extra data after
440 : : * struct vb2_buffer.
441 : : * For V4L2 this is a &struct vb2_v4l2_buffer.
442 : : * @fill_user_buffer: given a &vb2_buffer fill in the userspace structure.
443 : : * For V4L2 this is a &struct v4l2_buffer.
444 : : * @fill_vb2_buffer: given a userspace structure, fill in the &vb2_buffer.
445 : : * If the userspace structure is invalid, then this op
446 : : * will return an error.
447 : : * @copy_timestamp: copy the timestamp from a userspace structure to
448 : : * the &struct vb2_buffer.
449 : : */
450 : : struct vb2_buf_ops {
451 : : int (*verify_planes_array)(struct vb2_buffer *vb, const void *pb);
452 : : void (*init_buffer)(struct vb2_buffer *vb);
453 : : void (*fill_user_buffer)(struct vb2_buffer *vb, void *pb);
454 : : int (*fill_vb2_buffer)(struct vb2_buffer *vb, struct vb2_plane *planes);
455 : : void (*copy_timestamp)(struct vb2_buffer *vb, const void *pb);
456 : : };
457 : :
458 : : /**
459 : : * struct vb2_queue - a videobuf queue.
460 : : *
461 : : * @type: private buffer type whose content is defined by the vb2-core
462 : : * caller. For example, for V4L2, it should match
463 : : * the types defined on &enum v4l2_buf_type.
464 : : * @io_modes: supported io methods (see &enum vb2_io_modes).
465 : : * @alloc_devs: &struct device memory type/allocator-specific per-plane device
466 : : * @dev: device to use for the default allocation context if the driver
467 : : * doesn't fill in the @alloc_devs array.
468 : : * @dma_attrs: DMA attributes to use for the DMA.
469 : : * @bidirectional: when this flag is set the DMA direction for the buffers of
470 : : * this queue will be overridden with %DMA_BIDIRECTIONAL direction.
471 : : * This is useful in cases where the hardware (firmware) writes to
472 : : * a buffer which is mapped as read (%DMA_TO_DEVICE), or reads from
473 : : * buffer which is mapped for write (%DMA_FROM_DEVICE) in order
474 : : * to satisfy some internal hardware restrictions or adds a padding
475 : : * needed by the processing algorithm. In case the DMA mapping is
476 : : * not bidirectional but the hardware (firmware) trying to access
477 : : * the buffer (in the opposite direction) this could lead to an
478 : : * IOMMU protection faults.
479 : : * @fileio_read_once: report EOF after reading the first buffer
480 : : * @fileio_write_immediately: queue buffer after each write() call
481 : : * @allow_zero_bytesused: allow bytesused == 0 to be passed to the driver
482 : : * @quirk_poll_must_check_waiting_for_buffers: Return %EPOLLERR at poll when QBUF
483 : : * has not been called. This is a vb1 idiom that has been adopted
484 : : * also by vb2.
485 : : * @supports_requests: this queue supports the Request API.
486 : : * @requires_requests: this queue requires the Request API. If this is set to 1,
487 : : * then supports_requests must be set to 1 as well.
488 : : * @uses_qbuf: qbuf was used directly for this queue. Set to 1 the first
489 : : * time this is called. Set to 0 when the queue is canceled.
490 : : * If this is 1, then you cannot queue buffers from a request.
491 : : * @uses_requests: requests are used for this queue. Set to 1 the first time
492 : : * a request is queued. Set to 0 when the queue is canceled.
493 : : * If this is 1, then you cannot queue buffers directly.
494 : : * @lock: pointer to a mutex that protects the &struct vb2_queue. The
495 : : * driver can set this to a mutex to let the v4l2 core serialize
496 : : * the queuing ioctls. If the driver wants to handle locking
497 : : * itself, then this should be set to NULL. This lock is not used
498 : : * by the videobuf2 core API.
499 : : * @owner: The filehandle that 'owns' the buffers, i.e. the filehandle
500 : : * that called reqbufs, create_buffers or started fileio.
501 : : * This field is not used by the videobuf2 core API, but it allows
502 : : * drivers to easily associate an owner filehandle with the queue.
503 : : * @ops: driver-specific callbacks
504 : : * @mem_ops: memory allocator specific callbacks
505 : : * @buf_ops: callbacks to deliver buffer information.
506 : : * between user-space and kernel-space.
507 : : * @drv_priv: driver private data.
508 : : * @subsystem_flags: Flags specific to the subsystem (V4L2/DVB/etc.). Not used
509 : : * by the vb2 core.
510 : : * @buf_struct_size: size of the driver-specific buffer structure;
511 : : * "0" indicates the driver doesn't want to use a custom buffer
512 : : * structure type. for example, ``sizeof(struct vb2_v4l2_buffer)``
513 : : * will be used for v4l2.
514 : : * @timestamp_flags: Timestamp flags; ``V4L2_BUF_FLAG_TIMESTAMP_*`` and
515 : : * ``V4L2_BUF_FLAG_TSTAMP_SRC_*``
516 : : * @gfp_flags: additional gfp flags used when allocating the buffers.
517 : : * Typically this is 0, but it may be e.g. %GFP_DMA or %__GFP_DMA32
518 : : * to force the buffer allocation to a specific memory zone.
519 : : * @min_buffers_needed: the minimum number of buffers needed before
520 : : * @start_streaming can be called. Used when a DMA engine
521 : : * cannot be started unless at least this number of buffers
522 : : * have been queued into the driver.
523 : : */
524 : : /*
525 : : * Private elements (won't appear at the uAPI book):
526 : : * @mmap_lock: private mutex used when buffers are allocated/freed/mmapped
527 : : * @memory: current memory type used
528 : : * @dma_dir: DMA mapping direction.
529 : : * @bufs: videobuf buffer structures
530 : : * @num_buffers: number of allocated/used buffers
531 : : * @queued_list: list of buffers currently queued from userspace
532 : : * @queued_count: number of buffers queued and ready for streaming.
533 : : * @owned_by_drv_count: number of buffers owned by the driver
534 : : * @done_list: list of buffers ready to be dequeued to userspace
535 : : * @done_lock: lock to protect done_list list
536 : : * @done_wq: waitqueue for processes waiting for buffers ready to be dequeued
537 : : * @streaming: current streaming state
538 : : * @start_streaming_called: @start_streaming was called successfully and we
539 : : * started streaming.
540 : : * @error: a fatal error occurred on the queue
541 : : * @waiting_for_buffers: used in poll() to check if vb2 is still waiting for
542 : : * buffers. Only set for capture queues if qbuf has not yet been
543 : : * called since poll() needs to return %EPOLLERR in that situation.
544 : : * @is_multiplanar: set if buffer type is multiplanar
545 : : * @is_output: set if buffer type is output
546 : : * @copy_timestamp: set if vb2-core should set timestamps
547 : : * @last_buffer_dequeued: used in poll() and DQBUF to immediately return if the
548 : : * last decoded buffer was already dequeued. Set for capture queues
549 : : * when a buffer with the %V4L2_BUF_FLAG_LAST is dequeued.
550 : : * @fileio: file io emulator internal data, used only if emulator is active
551 : : * @threadio: thread io internal data, used only if thread is active
552 : : */
553 : : struct vb2_queue {
554 : : unsigned int type;
555 : : unsigned int io_modes;
556 : : struct device *dev;
557 : : unsigned long dma_attrs;
558 : : unsigned bidirectional:1;
559 : : unsigned fileio_read_once:1;
560 : : unsigned fileio_write_immediately:1;
561 : : unsigned allow_zero_bytesused:1;
562 : : unsigned quirk_poll_must_check_waiting_for_buffers:1;
563 : : unsigned supports_requests:1;
564 : : unsigned requires_requests:1;
565 : : unsigned uses_qbuf:1;
566 : : unsigned uses_requests:1;
567 : :
568 : : struct mutex *lock;
569 : : void *owner;
570 : :
571 : : const struct vb2_ops *ops;
572 : : const struct vb2_mem_ops *mem_ops;
573 : : const struct vb2_buf_ops *buf_ops;
574 : :
575 : : void *drv_priv;
576 : : u32 subsystem_flags;
577 : : unsigned int buf_struct_size;
578 : : u32 timestamp_flags;
579 : : gfp_t gfp_flags;
580 : : u32 min_buffers_needed;
581 : :
582 : : struct device *alloc_devs[VB2_MAX_PLANES];
583 : :
584 : : /* private: internal use only */
585 : : struct mutex mmap_lock;
586 : : unsigned int memory;
587 : : enum dma_data_direction dma_dir;
588 : : struct vb2_buffer *bufs[VB2_MAX_FRAME];
589 : : unsigned int num_buffers;
590 : :
591 : : struct list_head queued_list;
592 : : unsigned int queued_count;
593 : :
594 : : atomic_t owned_by_drv_count;
595 : : struct list_head done_list;
596 : : spinlock_t done_lock;
597 : : wait_queue_head_t done_wq;
598 : :
599 : : unsigned int streaming:1;
600 : : unsigned int start_streaming_called:1;
601 : : unsigned int error:1;
602 : : unsigned int waiting_for_buffers:1;
603 : : unsigned int waiting_in_dqbuf:1;
604 : : unsigned int is_multiplanar:1;
605 : : unsigned int is_output:1;
606 : : unsigned int copy_timestamp:1;
607 : : unsigned int last_buffer_dequeued:1;
608 : :
609 : : struct vb2_fileio_data *fileio;
610 : : struct vb2_threadio_data *threadio;
611 : :
612 : : #ifdef CONFIG_VIDEO_ADV_DEBUG
613 : : /*
614 : : * Counters for how often these queue-related ops are
615 : : * called. Used to check for unbalanced ops.
616 : : */
617 : : u32 cnt_queue_setup;
618 : : u32 cnt_wait_prepare;
619 : : u32 cnt_wait_finish;
620 : : u32 cnt_start_streaming;
621 : : u32 cnt_stop_streaming;
622 : : #endif
623 : : };
624 : :
625 : : /**
626 : : * vb2_plane_vaddr() - Return a kernel virtual address of a given plane.
627 : : * @vb: pointer to &struct vb2_buffer to which the plane in
628 : : * question belongs to.
629 : : * @plane_no: plane number for which the address is to be returned.
630 : : *
631 : : * This function returns a kernel virtual address of a given plane if
632 : : * such a mapping exist, NULL otherwise.
633 : : */
634 : : void *vb2_plane_vaddr(struct vb2_buffer *vb, unsigned int plane_no);
635 : :
636 : : /**
637 : : * vb2_plane_cookie() - Return allocator specific cookie for the given plane.
638 : : * @vb: pointer to &struct vb2_buffer to which the plane in
639 : : * question belongs to.
640 : : * @plane_no: plane number for which the cookie is to be returned.
641 : : *
642 : : * This function returns an allocator specific cookie for a given plane if
643 : : * available, NULL otherwise. The allocator should provide some simple static
644 : : * inline function, which would convert this cookie to the allocator specific
645 : : * type that can be used directly by the driver to access the buffer. This can
646 : : * be for example physical address, pointer to scatter list or IOMMU mapping.
647 : : */
648 : : void *vb2_plane_cookie(struct vb2_buffer *vb, unsigned int plane_no);
649 : :
650 : : /**
651 : : * vb2_buffer_done() - inform videobuf that an operation on a buffer
652 : : * is finished.
653 : : * @vb: pointer to &struct vb2_buffer to be used.
654 : : * @state: state of the buffer, as defined by &enum vb2_buffer_state.
655 : : * Either %VB2_BUF_STATE_DONE if the operation finished
656 : : * successfully, %VB2_BUF_STATE_ERROR if the operation finished
657 : : * with an error or %VB2_BUF_STATE_QUEUED.
658 : : *
659 : : * This function should be called by the driver after a hardware operation on
660 : : * a buffer is finished and the buffer may be returned to userspace. The driver
661 : : * cannot use this buffer anymore until it is queued back to it by videobuf
662 : : * by the means of &vb2_ops->buf_queue callback. Only buffers previously queued
663 : : * to the driver by &vb2_ops->buf_queue can be passed to this function.
664 : : *
665 : : * While streaming a buffer can only be returned in state DONE or ERROR.
666 : : * The &vb2_ops->start_streaming op can also return them in case the DMA engine
667 : : * cannot be started for some reason. In that case the buffers should be
668 : : * returned with state QUEUED to put them back into the queue.
669 : : */
670 : : void vb2_buffer_done(struct vb2_buffer *vb, enum vb2_buffer_state state);
671 : :
672 : : /**
673 : : * vb2_discard_done() - discard all buffers marked as DONE.
674 : : * @q: pointer to &struct vb2_queue with videobuf2 queue.
675 : : *
676 : : * This function is intended to be used with suspend/resume operations. It
677 : : * discards all 'done' buffers as they would be too old to be requested after
678 : : * resume.
679 : : *
680 : : * Drivers must stop the hardware and synchronize with interrupt handlers and/or
681 : : * delayed works before calling this function to make sure no buffer will be
682 : : * touched by the driver and/or hardware.
683 : : */
684 : : void vb2_discard_done(struct vb2_queue *q);
685 : :
686 : : /**
687 : : * vb2_wait_for_all_buffers() - wait until all buffers are given back to vb2.
688 : : * @q: pointer to &struct vb2_queue with videobuf2 queue.
689 : : *
690 : : * This function will wait until all buffers that have been given to the driver
691 : : * by &vb2_ops->buf_queue are given back to vb2 with vb2_buffer_done(). It
692 : : * doesn't call &vb2_ops->wait_prepare/&vb2_ops->wait_finish pair.
693 : : * It is intended to be called with all locks taken, for example from
694 : : * &vb2_ops->stop_streaming callback.
695 : : */
696 : : int vb2_wait_for_all_buffers(struct vb2_queue *q);
697 : :
698 : : /**
699 : : * vb2_core_querybuf() - query video buffer information.
700 : : * @q: pointer to &struct vb2_queue with videobuf2 queue.
701 : : * @index: id number of the buffer.
702 : : * @pb: buffer struct passed from userspace.
703 : : *
704 : : * Videobuf2 core helper to implement VIDIOC_QUERYBUF() operation. It is called
705 : : * internally by VB2 by an API-specific handler, like ``videobuf2-v4l2.h``.
706 : : *
707 : : * The passed buffer should have been verified.
708 : : *
709 : : * This function fills the relevant information for the userspace.
710 : : *
711 : : * Return: returns zero on success; an error code otherwise.
712 : : */
713 : : void vb2_core_querybuf(struct vb2_queue *q, unsigned int index, void *pb);
714 : :
715 : : /**
716 : : * vb2_core_reqbufs() - Initiate streaming.
717 : : * @q: pointer to &struct vb2_queue with videobuf2 queue.
718 : : * @memory: memory type, as defined by &enum vb2_memory.
719 : : * @count: requested buffer count.
720 : : *
721 : : * Videobuf2 core helper to implement VIDIOC_REQBUF() operation. It is called
722 : : * internally by VB2 by an API-specific handler, like ``videobuf2-v4l2.h``.
723 : : *
724 : : * This function:
725 : : *
726 : : * #) verifies streaming parameters passed from the userspace;
727 : : * #) sets up the queue;
728 : : * #) negotiates number of buffers and planes per buffer with the driver
729 : : * to be used during streaming;
730 : : * #) allocates internal buffer structures (&struct vb2_buffer), according to
731 : : * the agreed parameters;
732 : : * #) for MMAP memory type, allocates actual video memory, using the
733 : : * memory handling/allocation routines provided during queue initialization.
734 : : *
735 : : * If req->count is 0, all the memory will be freed instead.
736 : : *
737 : : * If the queue has been allocated previously by a previous vb2_core_reqbufs()
738 : : * call and the queue is not busy, memory will be reallocated.
739 : : *
740 : : * Return: returns zero on success; an error code otherwise.
741 : : */
742 : : int vb2_core_reqbufs(struct vb2_queue *q, enum vb2_memory memory,
743 : : unsigned int *count);
744 : :
745 : : /**
746 : : * vb2_core_create_bufs() - Allocate buffers and any required auxiliary structs
747 : : * @q: pointer to &struct vb2_queue with videobuf2 queue.
748 : : * @memory: memory type, as defined by &enum vb2_memory.
749 : : * @count: requested buffer count.
750 : : * @requested_planes: number of planes requested.
751 : : * @requested_sizes: array with the size of the planes.
752 : : *
753 : : * Videobuf2 core helper to implement VIDIOC_CREATE_BUFS() operation. It is
754 : : * called internally by VB2 by an API-specific handler, like
755 : : * ``videobuf2-v4l2.h``.
756 : : *
757 : : * This function:
758 : : *
759 : : * #) verifies parameter sanity;
760 : : * #) calls the &vb2_ops->queue_setup queue operation;
761 : : * #) performs any necessary memory allocations.
762 : : *
763 : : * Return: returns zero on success; an error code otherwise.
764 : : */
765 : : int vb2_core_create_bufs(struct vb2_queue *q, enum vb2_memory memory,
766 : : unsigned int *count, unsigned int requested_planes,
767 : : const unsigned int requested_sizes[]);
768 : :
769 : : /**
770 : : * vb2_core_prepare_buf() - Pass ownership of a buffer from userspace
771 : : * to the kernel.
772 : : * @q: pointer to &struct vb2_queue with videobuf2 queue.
773 : : * @index: id number of the buffer.
774 : : * @pb: buffer structure passed from userspace to
775 : : * &v4l2_ioctl_ops->vidioc_prepare_buf handler in driver.
776 : : *
777 : : * Videobuf2 core helper to implement VIDIOC_PREPARE_BUF() operation. It is
778 : : * called internally by VB2 by an API-specific handler, like
779 : : * ``videobuf2-v4l2.h``.
780 : : *
781 : : * The passed buffer should have been verified.
782 : : *
783 : : * This function calls vb2_ops->buf_prepare callback in the driver
784 : : * (if provided), in which driver-specific buffer initialization can
785 : : * be performed.
786 : : *
787 : : * Return: returns zero on success; an error code otherwise.
788 : : */
789 : : int vb2_core_prepare_buf(struct vb2_queue *q, unsigned int index, void *pb);
790 : :
791 : : /**
792 : : * vb2_core_qbuf() - Queue a buffer from userspace
793 : : *
794 : : * @q: pointer to &struct vb2_queue with videobuf2 queue.
795 : : * @index: id number of the buffer
796 : : * @pb: buffer structure passed from userspace to
797 : : * v4l2_ioctl_ops->vidioc_qbuf handler in driver
798 : : * @req: pointer to &struct media_request, may be NULL.
799 : : *
800 : : * Videobuf2 core helper to implement VIDIOC_QBUF() operation. It is called
801 : : * internally by VB2 by an API-specific handler, like ``videobuf2-v4l2.h``.
802 : : *
803 : : * This function:
804 : : *
805 : : * #) If @req is non-NULL, then the buffer will be bound to this
806 : : * media request and it returns. The buffer will be prepared and
807 : : * queued to the driver (i.e. the next two steps) when the request
808 : : * itself is queued.
809 : : * #) if necessary, calls &vb2_ops->buf_prepare callback in the driver
810 : : * (if provided), in which driver-specific buffer initialization can
811 : : * be performed;
812 : : * #) if streaming is on, queues the buffer in driver by the means of
813 : : * &vb2_ops->buf_queue callback for processing.
814 : : *
815 : : * Return: returns zero on success; an error code otherwise.
816 : : */
817 : : int vb2_core_qbuf(struct vb2_queue *q, unsigned int index, void *pb,
818 : : struct media_request *req);
819 : :
820 : : /**
821 : : * vb2_core_dqbuf() - Dequeue a buffer to the userspace
822 : : * @q: pointer to &struct vb2_queue with videobuf2 queue
823 : : * @pindex: pointer to the buffer index. May be NULL
824 : : * @pb: buffer structure passed from userspace to
825 : : * v4l2_ioctl_ops->vidioc_dqbuf handler in driver.
826 : : * @nonblocking: if true, this call will not sleep waiting for a buffer if no
827 : : * buffers ready for dequeuing are present. Normally the driver
828 : : * would be passing (file->f_flags & O_NONBLOCK) here.
829 : : *
830 : : * Videobuf2 core helper to implement VIDIOC_DQBUF() operation. It is called
831 : : * internally by VB2 by an API-specific handler, like ``videobuf2-v4l2.h``.
832 : : *
833 : : * This function:
834 : : *
835 : : * #) calls buf_finish callback in the driver (if provided), in which
836 : : * driver can perform any additional operations that may be required before
837 : : * returning the buffer to userspace, such as cache sync,
838 : : * #) the buffer struct members are filled with relevant information for
839 : : * the userspace.
840 : : *
841 : : * Return: returns zero on success; an error code otherwise.
842 : : */
843 : : int vb2_core_dqbuf(struct vb2_queue *q, unsigned int *pindex, void *pb,
844 : : bool nonblocking);
845 : :
846 : : /**
847 : : * vb2_core_streamon() - Implements VB2 stream ON logic
848 : : *
849 : : * @q: pointer to &struct vb2_queue with videobuf2 queue
850 : : * @type: type of the queue to be started.
851 : : * For V4L2, this is defined by &enum v4l2_buf_type type.
852 : : *
853 : : * Videobuf2 core helper to implement VIDIOC_STREAMON() operation. It is called
854 : : * internally by VB2 by an API-specific handler, like ``videobuf2-v4l2.h``.
855 : : *
856 : : * Return: returns zero on success; an error code otherwise.
857 : : */
858 : : int vb2_core_streamon(struct vb2_queue *q, unsigned int type);
859 : :
860 : : /**
861 : : * vb2_core_streamoff() - Implements VB2 stream OFF logic
862 : : *
863 : : * @q: pointer to &struct vb2_queue with videobuf2 queue
864 : : * @type: type of the queue to be started.
865 : : * For V4L2, this is defined by &enum v4l2_buf_type type.
866 : : *
867 : : * Videobuf2 core helper to implement VIDIOC_STREAMOFF() operation. It is
868 : : * called internally by VB2 by an API-specific handler, like
869 : : * ``videobuf2-v4l2.h``.
870 : : *
871 : : * Return: returns zero on success; an error code otherwise.
872 : : */
873 : : int vb2_core_streamoff(struct vb2_queue *q, unsigned int type);
874 : :
875 : : /**
876 : : * vb2_core_expbuf_dmabuf() - Export a buffer as a dma_buf structure
877 : : * @q: videobuf2 queue
878 : : * @type: buffer type
879 : : * @index: id number of the buffer
880 : : * @plane: index of the plane to be exported, 0 for single plane queues
881 : : * @flags: flags for newly created file, currently only O_CLOEXEC is
882 : : * supported, refer to manual of open syscall for more details
883 : : * @dmabuf: Returns the dmabuf pointer
884 : : *
885 : : */
886 : : int vb2_core_expbuf_dmabuf(struct vb2_queue *q, unsigned int type,
887 : : unsigned int index, unsigned int plane,
888 : : unsigned int flags, struct dma_buf **dmabuf);
889 : :
890 : : /**
891 : : * vb2_core_expbuf() - Export a buffer as a file descriptor.
892 : : * @q: pointer to &struct vb2_queue with videobuf2 queue.
893 : : * @fd: pointer to the file descriptor associated with DMABUF
894 : : * (set by driver).
895 : : * @type: buffer type.
896 : : * @index: id number of the buffer.
897 : : * @plane: index of the plane to be exported, 0 for single plane queues
898 : : * @flags: file flags for newly created file, as defined at
899 : : * include/uapi/asm-generic/fcntl.h.
900 : : * Currently, the only used flag is %O_CLOEXEC.
901 : : * is supported, refer to manual of open syscall for more details.
902 : : *
903 : : *
904 : : * Videobuf2 core helper to implement VIDIOC_EXPBUF() operation. It is called
905 : : * internally by VB2 by an API-specific handler, like ``videobuf2-v4l2.h``.
906 : : *
907 : : * Return: returns zero on success; an error code otherwise.
908 : : */
909 : : int vb2_core_expbuf(struct vb2_queue *q, int *fd, unsigned int type,
910 : : unsigned int index, unsigned int plane, unsigned int flags);
911 : :
912 : : /**
913 : : * vb2_core_queue_init() - initialize a videobuf2 queue
914 : : * @q: pointer to &struct vb2_queue with videobuf2 queue.
915 : : * This structure should be allocated in driver
916 : : *
917 : : * The &vb2_queue structure should be allocated by the driver. The driver is
918 : : * responsible of clearing it's content and setting initial values for some
919 : : * required entries before calling this function.
920 : : *
921 : : * .. note::
922 : : *
923 : : * The following fields at @q should be set before calling this function:
924 : : * &vb2_queue->ops, &vb2_queue->mem_ops, &vb2_queue->type.
925 : : */
926 : : int vb2_core_queue_init(struct vb2_queue *q);
927 : :
928 : : /**
929 : : * vb2_core_queue_release() - stop streaming, release the queue and free memory
930 : : * @q: pointer to &struct vb2_queue with videobuf2 queue.
931 : : *
932 : : * This function stops streaming and performs necessary clean ups, including
933 : : * freeing video buffer memory. The driver is responsible for freeing
934 : : * the &struct vb2_queue itself.
935 : : */
936 : : void vb2_core_queue_release(struct vb2_queue *q);
937 : :
938 : : /**
939 : : * vb2_queue_error() - signal a fatal error on the queue
940 : : * @q: pointer to &struct vb2_queue with videobuf2 queue.
941 : : *
942 : : * Flag that a fatal unrecoverable error has occurred and wake up all processes
943 : : * waiting on the queue. Polling will now set %EPOLLERR and queuing and dequeuing
944 : : * buffers will return %-EIO.
945 : : *
946 : : * The error flag will be cleared when canceling the queue, either from
947 : : * vb2_streamoff() or vb2_queue_release(). Drivers should thus not call this
948 : : * function before starting the stream, otherwise the error flag will remain set
949 : : * until the queue is released when closing the device node.
950 : : */
951 : : void vb2_queue_error(struct vb2_queue *q);
952 : :
953 : : /**
954 : : * vb2_mmap() - map video buffers into application address space.
955 : : * @q: pointer to &struct vb2_queue with videobuf2 queue.
956 : : * @vma: pointer to &struct vm_area_struct with the vma passed
957 : : * to the mmap file operation handler in the driver.
958 : : *
959 : : * Should be called from mmap file operation handler of a driver.
960 : : * This function maps one plane of one of the available video buffers to
961 : : * userspace. To map whole video memory allocated on reqbufs, this function
962 : : * has to be called once per each plane per each buffer previously allocated.
963 : : *
964 : : * When the userspace application calls mmap, it passes to it an offset returned
965 : : * to it earlier by the means of &v4l2_ioctl_ops->vidioc_querybuf handler.
966 : : * That offset acts as a "cookie", which is then used to identify the plane
967 : : * to be mapped.
968 : : *
969 : : * This function finds a plane with a matching offset and a mapping is performed
970 : : * by the means of a provided memory operation.
971 : : *
972 : : * The return values from this function are intended to be directly returned
973 : : * from the mmap handler in driver.
974 : : */
975 : : int vb2_mmap(struct vb2_queue *q, struct vm_area_struct *vma);
976 : :
977 : : #ifndef CONFIG_MMU
978 : : /**
979 : : * vb2_get_unmapped_area - map video buffers into application address space.
980 : : * @q: pointer to &struct vb2_queue with videobuf2 queue.
981 : : * @addr: memory address.
982 : : * @len: buffer size.
983 : : * @pgoff: page offset.
984 : : * @flags: memory flags.
985 : : *
986 : : * This function is used in noMMU platforms to propose address mapping
987 : : * for a given buffer. It's intended to be used as a handler for the
988 : : * &file_operations->get_unmapped_area operation.
989 : : *
990 : : * This is called by the mmap() syscall routines will call this
991 : : * to get a proposed address for the mapping, when ``!CONFIG_MMU``.
992 : : */
993 : : unsigned long vb2_get_unmapped_area(struct vb2_queue *q,
994 : : unsigned long addr,
995 : : unsigned long len,
996 : : unsigned long pgoff,
997 : : unsigned long flags);
998 : : #endif
999 : :
1000 : : /**
1001 : : * vb2_core_poll() - implements poll syscall() logic.
1002 : : * @q: pointer to &struct vb2_queue with videobuf2 queue.
1003 : : * @file: &struct file argument passed to the poll
1004 : : * file operation handler.
1005 : : * @wait: &poll_table wait argument passed to the poll
1006 : : * file operation handler.
1007 : : *
1008 : : * This function implements poll file operation handler for a driver.
1009 : : * For CAPTURE queues, if a buffer is ready to be dequeued, the userspace will
1010 : : * be informed that the file descriptor of a video device is available for
1011 : : * reading.
1012 : : * For OUTPUT queues, if a buffer is ready to be dequeued, the file descriptor
1013 : : * will be reported as available for writing.
1014 : : *
1015 : : * The return values from this function are intended to be directly returned
1016 : : * from poll handler in driver.
1017 : : */
1018 : : __poll_t vb2_core_poll(struct vb2_queue *q, struct file *file,
1019 : : poll_table *wait);
1020 : :
1021 : : /**
1022 : : * vb2_read() - implements read() syscall logic.
1023 : : * @q: pointer to &struct vb2_queue with videobuf2 queue.
1024 : : * @data: pointed to target userspace buffer
1025 : : * @count: number of bytes to read
1026 : : * @ppos: file handle position tracking pointer
1027 : : * @nonblock: mode selector (1 means blocking calls, 0 means nonblocking)
1028 : : */
1029 : : size_t vb2_read(struct vb2_queue *q, char __user *data, size_t count,
1030 : : loff_t *ppos, int nonblock);
1031 : : /**
1032 : : * vb2_read() - implements write() syscall logic.
1033 : : * @q: pointer to &struct vb2_queue with videobuf2 queue.
1034 : : * @data: pointed to target userspace buffer
1035 : : * @count: number of bytes to write
1036 : : * @ppos: file handle position tracking pointer
1037 : : * @nonblock: mode selector (1 means blocking calls, 0 means nonblocking)
1038 : : */
1039 : : size_t vb2_write(struct vb2_queue *q, const char __user *data, size_t count,
1040 : : loff_t *ppos, int nonblock);
1041 : :
1042 : : /**
1043 : : * typedef vb2_thread_fnc - callback function for use with vb2_thread.
1044 : : *
1045 : : * @vb: pointer to struct &vb2_buffer.
1046 : : * @priv: pointer to a private data.
1047 : : *
1048 : : * This is called whenever a buffer is dequeued in the thread.
1049 : : */
1050 : : typedef int (*vb2_thread_fnc)(struct vb2_buffer *vb, void *priv);
1051 : :
1052 : : /**
1053 : : * vb2_thread_start() - start a thread for the given queue.
1054 : : * @q: pointer to &struct vb2_queue with videobuf2 queue.
1055 : : * @fnc: &vb2_thread_fnc callback function.
1056 : : * @priv: priv pointer passed to the callback function.
1057 : : * @thread_name:the name of the thread. This will be prefixed with "vb2-".
1058 : : *
1059 : : * This starts a thread that will queue and dequeue until an error occurs
1060 : : * or vb2_thread_stop() is called.
1061 : : *
1062 : : * .. attention::
1063 : : *
1064 : : * This function should not be used for anything else but the videobuf2-dvb
1065 : : * support. If you think you have another good use-case for this, then please
1066 : : * contact the linux-media mailing list first.
1067 : : */
1068 : : int vb2_thread_start(struct vb2_queue *q, vb2_thread_fnc fnc, void *priv,
1069 : : const char *thread_name);
1070 : :
1071 : : /**
1072 : : * vb2_thread_stop() - stop the thread for the given queue.
1073 : : * @q: pointer to &struct vb2_queue with videobuf2 queue.
1074 : : */
1075 : : int vb2_thread_stop(struct vb2_queue *q);
1076 : :
1077 : : /**
1078 : : * vb2_is_streaming() - return streaming status of the queue.
1079 : : * @q: pointer to &struct vb2_queue with videobuf2 queue.
1080 : : */
1081 : : static inline bool vb2_is_streaming(struct vb2_queue *q)
1082 : : {
1083 : 0 : return q->streaming;
1084 : : }
1085 : :
1086 : : /**
1087 : : * vb2_fileio_is_active() - return true if fileio is active.
1088 : : * @q: pointer to &struct vb2_queue with videobuf2 queue.
1089 : : *
1090 : : * This returns true if read() or write() is used to stream the data
1091 : : * as opposed to stream I/O. This is almost never an important distinction,
1092 : : * except in rare cases. One such case is that using read() or write() to
1093 : : * stream a format using %V4L2_FIELD_ALTERNATE is not allowed since there
1094 : : * is no way you can pass the field information of each buffer to/from
1095 : : * userspace. A driver that supports this field format should check for
1096 : : * this in the &vb2_ops->queue_setup op and reject it if this function returns
1097 : : * true.
1098 : : */
1099 : : static inline bool vb2_fileio_is_active(struct vb2_queue *q)
1100 : : {
1101 : 0 : return q->fileio;
1102 : : }
1103 : :
1104 : : /**
1105 : : * vb2_is_busy() - return busy status of the queue.
1106 : : * @q: pointer to &struct vb2_queue with videobuf2 queue.
1107 : : *
1108 : : * This function checks if queue has any buffers allocated.
1109 : : */
1110 : : static inline bool vb2_is_busy(struct vb2_queue *q)
1111 : : {
1112 : 0 : return (q->num_buffers > 0);
1113 : : }
1114 : :
1115 : : /**
1116 : : * vb2_get_drv_priv() - return driver private data associated with the queue.
1117 : : * @q: pointer to &struct vb2_queue with videobuf2 queue.
1118 : : */
1119 : : static inline void *vb2_get_drv_priv(struct vb2_queue *q)
1120 : : {
1121 : 0 : return q->drv_priv;
1122 : : }
1123 : :
1124 : : /**
1125 : : * vb2_set_plane_payload() - set bytesused for the plane @plane_no.
1126 : : * @vb: pointer to &struct vb2_buffer to which the plane in
1127 : : * question belongs to.
1128 : : * @plane_no: plane number for which payload should be set.
1129 : : * @size: payload in bytes.
1130 : : */
1131 : : static inline void vb2_set_plane_payload(struct vb2_buffer *vb,
1132 : : unsigned int plane_no, unsigned long size)
1133 : : {
1134 [ # # # # ]: 0 : if (plane_no < vb->num_planes)
1135 : 0 : vb->planes[plane_no].bytesused = size;
1136 : : }
1137 : :
1138 : : /**
1139 : : * vb2_get_plane_payload() - get bytesused for the plane plane_no
1140 : : * @vb: pointer to &struct vb2_buffer to which the plane in
1141 : : * question belongs to.
1142 : : * @plane_no: plane number for which payload should be set.
1143 : : */
1144 : : static inline unsigned long vb2_get_plane_payload(struct vb2_buffer *vb,
1145 : : unsigned int plane_no)
1146 : : {
1147 [ # # ]: 0 : if (plane_no < vb->num_planes)
1148 : 0 : return vb->planes[plane_no].bytesused;
1149 : : return 0;
1150 : : }
1151 : :
1152 : : /**
1153 : : * vb2_plane_size() - return plane size in bytes.
1154 : : * @vb: pointer to &struct vb2_buffer to which the plane in
1155 : : * question belongs to.
1156 : : * @plane_no: plane number for which size should be returned.
1157 : : */
1158 : : static inline unsigned long
1159 : : vb2_plane_size(struct vb2_buffer *vb, unsigned int plane_no)
1160 : : {
1161 [ # # # # : 0 : if (plane_no < vb->num_planes)
# # ]
1162 : 0 : return vb->planes[plane_no].length;
1163 : : return 0;
1164 : : }
1165 : :
1166 : : /**
1167 : : * vb2_start_streaming_called() - return streaming status of driver.
1168 : : * @q: pointer to &struct vb2_queue with videobuf2 queue.
1169 : : */
1170 : : static inline bool vb2_start_streaming_called(struct vb2_queue *q)
1171 : : {
1172 : : return q->start_streaming_called;
1173 : : }
1174 : :
1175 : : /**
1176 : : * vb2_clear_last_buffer_dequeued() - clear last buffer dequeued flag of queue.
1177 : : * @q: pointer to &struct vb2_queue with videobuf2 queue.
1178 : : */
1179 : : static inline void vb2_clear_last_buffer_dequeued(struct vb2_queue *q)
1180 : : {
1181 : : q->last_buffer_dequeued = false;
1182 : : }
1183 : :
1184 : : /**
1185 : : * vb2_get_buffer() - get a buffer from a queue
1186 : : * @q: pointer to &struct vb2_queue with videobuf2 queue.
1187 : : * @index: buffer index
1188 : : *
1189 : : * This function obtains a buffer from a queue, by its index.
1190 : : * Keep in mind that there is no refcounting involved in this
1191 : : * operation, so the buffer lifetime should be taken into
1192 : : * consideration.
1193 : : */
1194 : : static inline struct vb2_buffer *vb2_get_buffer(struct vb2_queue *q,
1195 : : unsigned int index)
1196 : : {
1197 : : if (index < q->num_buffers)
1198 : : return q->bufs[index];
1199 : : return NULL;
1200 : : }
1201 : :
1202 : : /*
1203 : : * The following functions are not part of the vb2 core API, but are useful
1204 : : * functions for videobuf2-*.
1205 : : */
1206 : :
1207 : : /**
1208 : : * vb2_buffer_in_use() - return true if the buffer is in use and
1209 : : * the queue cannot be freed (by the means of VIDIOC_REQBUFS(0)) call.
1210 : : *
1211 : : * @vb: buffer for which plane size should be returned.
1212 : : * @q: pointer to &struct vb2_queue with videobuf2 queue.
1213 : : */
1214 : : bool vb2_buffer_in_use(struct vb2_queue *q, struct vb2_buffer *vb);
1215 : :
1216 : : /**
1217 : : * vb2_verify_memory_type() - Check whether the memory type and buffer type
1218 : : * passed to a buffer operation are compatible with the queue.
1219 : : *
1220 : : * @q: pointer to &struct vb2_queue with videobuf2 queue.
1221 : : * @memory: memory model, as defined by enum &vb2_memory.
1222 : : * @type: private buffer type whose content is defined by the vb2-core
1223 : : * caller. For example, for V4L2, it should match
1224 : : * the types defined on enum &v4l2_buf_type.
1225 : : */
1226 : : int vb2_verify_memory_type(struct vb2_queue *q,
1227 : : enum vb2_memory memory, unsigned int type);
1228 : :
1229 : : /**
1230 : : * vb2_request_object_is_buffer() - return true if the object is a buffer
1231 : : *
1232 : : * @obj: the request object.
1233 : : */
1234 : : bool vb2_request_object_is_buffer(struct media_request_object *obj);
1235 : :
1236 : : /**
1237 : : * vb2_request_buffer_cnt() - return the number of buffers in the request
1238 : : *
1239 : : * @req: the request.
1240 : : */
1241 : : unsigned int vb2_request_buffer_cnt(struct media_request *req);
1242 : :
1243 : : #endif /* _MEDIA_VIDEOBUF2_CORE_H */
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