1 /*
2 * videobuf2-core.h - V4L2 driver helper 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/videodev2.h>
19
20 struct vb2_alloc_ctx;
21 struct vb2_fileio_data;
22
23 /**
24 * struct vb2_mem_ops - memory handling/memory allocator operations
25 * @alloc: allocate video memory and, optionally, allocator private data,
26 * return NULL on failure or a pointer to allocator private,
27 * per-buffer data on success; the returned private structure
28 * will then be passed as buf_priv argument to other ops in this
29 * structure
30 * @put: inform the allocator that the buffer will no longer be used;
31 * usually will result in the allocator freeing the buffer (if
32 * no other users of this buffer are present); the buf_priv
33 * argument is the allocator private per-buffer structure
34 * previously returned from the alloc callback
35 * @get_userptr: acquire userspace memory for a hardware operation; used for
36 * USERPTR memory types; vaddr is the address passed to the
37 * videobuf layer when queuing a video buffer of USERPTR type;
38 * should return an allocator private per-buffer structure
39 * associated with the buffer on success, NULL on failure;
40 * the returned private structure will then be passed as buf_priv
41 * argument to other ops in this structure
42 * @put_userptr: inform the allocator that a USERPTR buffer will no longer
43 * be used
44 * @vaddr: return a kernel virtual address to a given memory buffer
45 * associated with the passed private structure or NULL if no
46 * such mapping exists
47 * @cookie: return allocator specific cookie for a given memory buffer
48 * associated with the passed private structure or NULL if not
49 * available
50 * @num_users: return the current number of users of a memory buffer;
51 * return 1 if the videobuf layer (or actually the driver using
52 * it) is the only user
53 * @mmap: setup a userspace mapping for a given memory buffer under
54 * the provided virtual memory region
55 *
56 * Required ops for USERPTR types: get_userptr, put_userptr.
57 * Required ops for MMAP types: alloc, put, num_users, mmap.
58 * Required ops for read/write access types: alloc, put, num_users, vaddr
59 */
60 struct vb2_mem_ops {
61 void *(*alloc)(void *alloc_ctx, unsigned long size);
62 void (*put)(void *buf_priv);
63
64 void *(*get_userptr)(void *alloc_ctx, unsigned long vaddr,
65 unsigned long size, int write);
66 void (*put_userptr)(void *buf_priv);
67
68 void *(*vaddr)(void *buf_priv);
69 void *(*cookie)(void *buf_priv);
70
71 unsigned int (*num_users)(void *buf_priv);
72
73 int (*mmap)(void *buf_priv, struct vm_area_struct *vma);
74 };
75
76 struct vb2_plane {
77 void *mem_priv;
78 int mapped:1;
79 };
80
81 /**
82 * enum vb2_io_modes - queue access methods
83 * @VB2_MMAP: driver supports MMAP with streaming API
84 * @VB2_USERPTR: driver supports USERPTR with streaming API
85 * @VB2_READ: driver supports read() style access
86 * @VB2_WRITE: driver supports write() style access
87 */
88 enum vb2_io_modes {
89 VB2_MMAP = (1 << 0),
90 VB2_USERPTR = (1 << 1),
91 VB2_READ = (1 << 2),
92 VB2_WRITE = (1 << 3),
93 };
94
95 /**
96 * enum vb2_fileio_flags - flags for selecting a mode of the file io emulator,
97 * by default the 'streaming' style is used by the file io emulator
98 * @VB2_FILEIO_READ_ONCE: report EOF after reading the first buffer
99 * @VB2_FILEIO_WRITE_IMMEDIATELY: queue buffer after each write() call
100 */
101 enum vb2_fileio_flags {
102 VB2_FILEIO_READ_ONCE = (1 << 0),
103 VB2_FILEIO_WRITE_IMMEDIATELY = (1 << 1),
104 };
105
106 /**
107 * enum vb2_buffer_state - current video buffer state
108 * @VB2_BUF_STATE_DEQUEUED: buffer under userspace control
109 * @VB2_BUF_STATE_QUEUED: buffer queued in videobuf, but not in driver
110 * @VB2_BUF_STATE_ACTIVE: buffer queued in driver and possibly used
111 * in a hardware operation
112 * @VB2_BUF_STATE_DONE: buffer returned from driver to videobuf, but
113 * not yet dequeued to userspace
114 * @VB2_BUF_STATE_ERROR: same as above, but the operation on the buffer
115 * has ended with an error, which will be reported
116 * to the userspace when it is dequeued
117 */
118 enum vb2_buffer_state {
119 VB2_BUF_STATE_DEQUEUED,
120 VB2_BUF_STATE_QUEUED,
121 VB2_BUF_STATE_ACTIVE,
122 VB2_BUF_STATE_DONE,
123 VB2_BUF_STATE_ERROR,
124 };
125
126 struct vb2_queue;
127
128 /**
129 * struct vb2_buffer - represents a video buffer
130 * @v4l2_buf: struct v4l2_buffer associated with this buffer; can
131 * be read by the driver and relevant entries can be
132 * changed by the driver in case of CAPTURE types
133 * (such as timestamp)
134 * @v4l2_planes: struct v4l2_planes associated with this buffer; can
135 * be read by the driver and relevant entries can be
136 * changed by the driver in case of CAPTURE types
137 * (such as bytesused); NOTE that even for single-planar
138 * types, the v4l2_planes[0] struct should be used
139 * instead of v4l2_buf for filling bytesused - drivers
140 * should use the vb2_set_plane_payload() function for that
141 * @vb2_queue: the queue to which this driver belongs
142 * @num_planes: number of planes in the buffer
143 * on an internal driver queue
144 * @state: current buffer state; do not change
145 * @queued_entry: entry on the queued buffers list, which holds all
146 * buffers queued from userspace
147 * @done_entry: entry on the list that stores all buffers ready to
148 * be dequeued to userspace
149 * @planes: private per-plane information; do not change
150 * @num_planes_mapped: number of mapped planes; do not change
151 */
152 struct vb2_buffer {
153 struct v4l2_buffer v4l2_buf;
154 struct v4l2_plane v4l2_planes[VIDEO_MAX_PLANES];
155
156 struct vb2_queue *vb2_queue;
157
158 unsigned int num_planes;
159
160 /* Private: internal use only */
161 enum vb2_buffer_state state;
162
163 struct list_head queued_entry;
164 struct list_head done_entry;
165
166 struct vb2_plane planes[VIDEO_MAX_PLANES];
167 unsigned int num_planes_mapped;
168 };
169
170 /**
171 * struct vb2_ops - driver-specific callbacks
172 *
173 * @queue_setup: called from a VIDIOC_REQBUFS handler, before
174 * memory allocation; driver should return the required
175 * number of buffers in num_buffers, the required number
176 * of planes per buffer in num_planes; the size of each
177 * plane should be set in the sizes[] array and optional
178 * per-plane allocator specific context in alloc_ctxs[]
179 * array
180 * @wait_prepare: release any locks taken while calling vb2 functions;
181 * it is called before an ioctl needs to wait for a new
182 * buffer to arrive; required to avoid a deadlock in
183 * blocking access type
184 * @wait_finish: reacquire all locks released in the previous callback;
185 * required to continue operation after sleeping while
186 * waiting for a new buffer to arrive
187 * @buf_init: called once after allocating a buffer (in MMAP case)
188 * or after acquiring a new USERPTR buffer; drivers may
189 * perform additional buffer-related initialization;
190 * initialization failure (return != 0) will prevent
191 * queue setup from completing successfully; optional
192 * @buf_prepare: called every time the buffer is queued from userspace;
193 * drivers may perform any initialization required before
194 * each hardware operation in this callback;
195 * if an error is returned, the buffer will not be queued
196 * in driver; optional
197 * @buf_finish: called before every dequeue of the buffer back to
198 * userspace; drivers may perform any operations required
199 * before userspace accesses the buffer; optional
200 * @buf_cleanup: called once before the buffer is freed; drivers may
201 * perform any additional cleanup; optional
202 * @start_streaming: called once before entering 'streaming' state; enables
203 * driver to receive buffers over buf_queue() callback
204 * @stop_streaming: called when 'streaming' state must be disabled; driver
205 * should stop any DMA transactions or wait until they
206 * finish and give back all buffers it got from buf_queue()
207 * callback; may use vb2_wait_for_all_buffers() function
208 * @buf_queue: passes buffer vb to the driver; driver may start
209 * hardware operation on this buffer; driver should give
210 * the buffer back by calling vb2_buffer_done() function
211 */
212 struct vb2_ops {
213 int (*queue_setup)(struct vb2_queue *q, unsigned int *num_buffers,
214 unsigned int *num_planes, unsigned long sizes[],
215 void *alloc_ctxs[]);
216
217 void (*wait_prepare)(struct vb2_queue *q);
218 void (*wait_finish)(struct vb2_queue *q);
219
220 int (*buf_init)(struct vb2_buffer *vb);
221 int (*buf_prepare)(struct vb2_buffer *vb);
222 int (*buf_finish)(struct vb2_buffer *vb);
223 void (*buf_cleanup)(struct vb2_buffer *vb);
224
225 int (*start_streaming)(struct vb2_queue *q);
226 int (*stop_streaming)(struct vb2_queue *q);
227
228 void (*buf_queue)(struct vb2_buffer *vb);
229 };
230
231 /**
232 * struct vb2_queue - a videobuf queue
233 *
234 * @type: queue type (see V4L2_BUF_TYPE_* in linux/videodev2.h
235 * @io_modes: supported io methods (see vb2_io_modes enum)
236 * @io_flags: additional io flags (see vb2_fileio_flags enum)
237 * @ops: driver-specific callbacks
238 * @mem_ops: memory allocator specific callbacks
239 * @drv_priv: driver private data
240 * @buf_struct_size: size of the driver-specific buffer structure;
241 * "0" indicates the driver doesn't want to use a custom buffer
242 * structure type, so sizeof(struct vb2_buffer) will is used
243 *
244 * @memory: current memory type used
245 * @bufs: videobuf buffer structures
246 * @num_buffers: number of allocated/used buffers
247 * @queued_list: list of buffers currently queued from userspace
248 * @queued_count: number of buffers owned by the driver
249 * @done_list: list of buffers ready to be dequeued to userspace
250 * @done_lock: lock to protect done_list list
251 * @done_wq: waitqueue for processes waiting for buffers ready to be dequeued
252 * @alloc_ctx: memory type/allocator-specific contexts for each plane
253 * @streaming: current streaming state
254 * @fileio: file io emulator internal data, used only if emulator is active
255 */
256 struct vb2_queue {
257 enum v4l2_buf_type type;
258 unsigned int io_modes;
259 unsigned int io_flags;
260
261 const struct vb2_ops *ops;
262 const struct vb2_mem_ops *mem_ops;
263 void *drv_priv;
264 unsigned int buf_struct_size;
265
266 /* private: internal use only */
267 enum v4l2_memory memory;
268 struct vb2_buffer *bufs[VIDEO_MAX_FRAME];
269 unsigned int num_buffers;
270
271 struct list_head queued_list;
272
273 atomic_t queued_count;
274 struct list_head done_list;
275 spinlock_t done_lock;
276 wait_queue_head_t done_wq;
277
278 void *alloc_ctx[VIDEO_MAX_PLANES];
279
280 unsigned int streaming:1;
281
282 struct vb2_fileio_data *fileio;
283 };
284
285 void *vb2_plane_vaddr(struct vb2_buffer *vb, unsigned int plane_no);
286 void *vb2_plane_cookie(struct vb2_buffer *vb, unsigned int plane_no);
287
288 void vb2_buffer_done(struct vb2_buffer *vb, enum vb2_buffer_state state);
289 int vb2_wait_for_all_buffers(struct vb2_queue *q);
290
291 int vb2_querybuf(struct vb2_queue *q, struct v4l2_buffer *b);
292 int vb2_reqbufs(struct vb2_queue *q, struct v4l2_requestbuffers *req);
293
294 int vb2_queue_init(struct vb2_queue *q);
295
296 void vb2_queue_release(struct vb2_queue *q);
297
298 int vb2_qbuf(struct vb2_queue *q, struct v4l2_buffer *b);
299 int vb2_dqbuf(struct vb2_queue *q, struct v4l2_buffer *b, bool nonblocking);
300
301 int vb2_streamon(struct vb2_queue *q, enum v4l2_buf_type type);
302 int vb2_streamoff(struct vb2_queue *q, enum v4l2_buf_type type);
303
304 int vb2_mmap(struct vb2_queue *q, struct vm_area_struct *vma);
305 unsigned int vb2_poll(struct vb2_queue *q, struct file *file, poll_table *wait);
306 size_t vb2_read(struct vb2_queue *q, char __user *data, size_t count,
307 loff_t *ppos, int nonblock);
308 size_t vb2_write(struct vb2_queue *q, char __user *data, size_t count,
309 loff_t *ppos, int nonblock);
310
311 /**
312 * vb2_is_streaming() - return streaming status of the queue
313 * @q: videobuf queue
314 */
vb2_is_streaming(struct vb2_queue * q)315 static inline bool vb2_is_streaming(struct vb2_queue *q)
316 {
317 return q->streaming;
318 }
319
320 /**
321 * vb2_is_busy() - return busy status of the queue
322 * @q: videobuf queue
323 *
324 * This function checks if queue has any buffers allocated.
325 */
vb2_is_busy(struct vb2_queue * q)326 static inline bool vb2_is_busy(struct vb2_queue *q)
327 {
328 return (q->num_buffers > 0);
329 }
330
331 /**
332 * vb2_get_drv_priv() - return driver private data associated with the queue
333 * @q: videobuf queue
334 */
vb2_get_drv_priv(struct vb2_queue * q)335 static inline void *vb2_get_drv_priv(struct vb2_queue *q)
336 {
337 return q->drv_priv;
338 }
339
340 /**
341 * vb2_set_plane_payload() - set bytesused for the plane plane_no
342 * @vb: buffer for which plane payload should be set
343 * @plane_no: plane number for which payload should be set
344 * @size: payload in bytes
345 */
vb2_set_plane_payload(struct vb2_buffer * vb,unsigned int plane_no,unsigned long size)346 static inline void vb2_set_plane_payload(struct vb2_buffer *vb,
347 unsigned int plane_no, unsigned long size)
348 {
349 if (plane_no < vb->num_planes)
350 vb->v4l2_planes[plane_no].bytesused = size;
351 }
352
353 /**
354 * vb2_get_plane_payload() - get bytesused for the plane plane_no
355 * @vb: buffer for which plane payload should be set
356 * @plane_no: plane number for which payload should be set
357 * @size: payload in bytes
358 */
vb2_get_plane_payload(struct vb2_buffer * vb,unsigned int plane_no)359 static inline unsigned long vb2_get_plane_payload(struct vb2_buffer *vb,
360 unsigned int plane_no)
361 {
362 if (plane_no < vb->num_planes)
363 return vb->v4l2_planes[plane_no].bytesused;
364 return 0;
365 }
366
367 /**
368 * vb2_plane_size() - return plane size in bytes
369 * @vb: buffer for which plane size should be returned
370 * @plane_no: plane number for which size should be returned
371 */
372 static inline unsigned long
vb2_plane_size(struct vb2_buffer * vb,unsigned int plane_no)373 vb2_plane_size(struct vb2_buffer *vb, unsigned int plane_no)
374 {
375 if (plane_no < vb->num_planes)
376 return vb->v4l2_planes[plane_no].length;
377 return 0;
378 }
379
380 #endif /* _MEDIA_VIDEOBUF2_CORE_H */
381