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 }; 79 80 /** 81 * enum vb2_io_modes - queue access methods 82 * @VB2_MMAP: driver supports MMAP with streaming API 83 * @VB2_USERPTR: driver supports USERPTR with streaming API 84 * @VB2_READ: driver supports read() style access 85 * @VB2_WRITE: driver supports write() style access 86 */ 87 enum vb2_io_modes { 88 VB2_MMAP = (1 << 0), 89 VB2_USERPTR = (1 << 1), 90 VB2_READ = (1 << 2), 91 VB2_WRITE = (1 << 3), 92 }; 93 94 /** 95 * enum vb2_fileio_flags - flags for selecting a mode of the file io emulator, 96 * by default the 'streaming' style is used by the file io emulator 97 * @VB2_FILEIO_READ_ONCE: report EOF after reading the first buffer 98 * @VB2_FILEIO_WRITE_IMMEDIATELY: queue buffer after each write() call 99 */ 100 enum vb2_fileio_flags { 101 VB2_FILEIO_READ_ONCE = (1 << 0), 102 VB2_FILEIO_WRITE_IMMEDIATELY = (1 << 1), 103 }; 104 105 /** 106 * enum vb2_buffer_state - current video buffer state 107 * @VB2_BUF_STATE_DEQUEUED: buffer under userspace control 108 * @VB2_BUF_STATE_PREPARED: buffer prepared in videobuf and by the driver 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_PREPARED, 121 VB2_BUF_STATE_QUEUED, 122 VB2_BUF_STATE_ACTIVE, 123 VB2_BUF_STATE_DONE, 124 VB2_BUF_STATE_ERROR, 125 }; 126 127 struct vb2_queue; 128 129 /** 130 * struct vb2_buffer - represents a video buffer 131 * @v4l2_buf: struct v4l2_buffer associated with this buffer; can 132 * be read by the driver and relevant entries can be 133 * changed by the driver in case of CAPTURE types 134 * (such as timestamp) 135 * @v4l2_planes: struct v4l2_planes associated with this buffer; can 136 * be read by the driver and relevant entries can be 137 * changed by the driver in case of CAPTURE types 138 * (such as bytesused); NOTE that even for single-planar 139 * types, the v4l2_planes[0] struct should be used 140 * instead of v4l2_buf for filling bytesused - drivers 141 * should use the vb2_set_plane_payload() function for that 142 * @vb2_queue: the queue to which this driver belongs 143 * @num_planes: number of planes in the buffer 144 * on an internal driver queue 145 * @state: current buffer state; do not change 146 * @queued_entry: entry on the queued buffers list, which holds all 147 * buffers queued from userspace 148 * @done_entry: entry on the list that stores all buffers ready to 149 * be dequeued to userspace 150 * @planes: private per-plane information; 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 }; 168 169 /** 170 * struct vb2_ops - driver-specific callbacks 171 * 172 * @queue_setup: called from VIDIOC_REQBUFS and VIDIOC_CREATE_BUFS 173 * handlers before memory allocation, or, if 174 * *num_planes != 0, after the allocation to verify a 175 * smaller number of buffers. Driver should return 176 * the required number of buffers in *num_buffers, the 177 * required number of planes per buffer in *num_planes; the 178 * size of each plane should be set in the sizes[] array 179 * and optional per-plane allocator specific context in the 180 * alloc_ctxs[] array. When called from VIDIOC_REQBUFS, 181 * fmt == NULL, the driver has to use the currently 182 * configured format and *num_buffers is the total number 183 * of buffers, that are being allocated. When called from 184 * VIDIOC_CREATE_BUFS, fmt != NULL and it describes the 185 * target frame format. In this case *num_buffers are being 186 * allocated additionally to q->num_buffers. 187 * @wait_prepare: release any locks taken while calling vb2 functions; 188 * it is called before an ioctl needs to wait for a new 189 * buffer to arrive; required to avoid a deadlock in 190 * blocking access type 191 * @wait_finish: reacquire all locks released in the previous callback; 192 * required to continue operation after sleeping while 193 * waiting for a new buffer to arrive 194 * @buf_init: called once after allocating a buffer (in MMAP case) 195 * or after acquiring a new USERPTR buffer; drivers may 196 * perform additional buffer-related initialization; 197 * initialization failure (return != 0) will prevent 198 * queue setup from completing successfully; optional 199 * @buf_prepare: called every time the buffer is queued from userspace 200 * and from the VIDIOC_PREPARE_BUF ioctl; drivers may 201 * perform any initialization required before each hardware 202 * operation in this callback; if an error is returned, the 203 * buffer will not be queued in driver; optional 204 * @buf_finish: called before every dequeue of the buffer back to 205 * userspace; drivers may perform any operations required 206 * before userspace accesses the buffer; optional 207 * @buf_cleanup: called once before the buffer is freed; drivers may 208 * perform any additional cleanup; optional 209 * @start_streaming: called once to enter 'streaming' state; the driver may 210 * receive buffers with @buf_queue callback before 211 * @start_streaming is called; the driver gets the number 212 * of already queued buffers in count parameter; driver 213 * can return an error if hardware fails or not enough 214 * buffers has been queued, in such case all buffers that 215 * have been already given by the @buf_queue callback are 216 * invalidated. 217 * @stop_streaming: called when 'streaming' state must be disabled; driver 218 * should stop any DMA transactions or wait until they 219 * finish and give back all buffers it got from buf_queue() 220 * callback; may use vb2_wait_for_all_buffers() function 221 * @buf_queue: passes buffer vb to the driver; driver may start 222 * hardware operation on this buffer; driver should give 223 * the buffer back by calling vb2_buffer_done() function; 224 * it is allways called after calling STREAMON ioctl; 225 * might be called before start_streaming callback if user 226 * pre-queued buffers before calling STREAMON 227 */ 228 struct vb2_ops { 229 int (*queue_setup)(struct vb2_queue *q, const struct v4l2_format *fmt, 230 unsigned int *num_buffers, unsigned int *num_planes, 231 unsigned int sizes[], void *alloc_ctxs[]); 232 233 void (*wait_prepare)(struct vb2_queue *q); 234 void (*wait_finish)(struct vb2_queue *q); 235 236 int (*buf_init)(struct vb2_buffer *vb); 237 int (*buf_prepare)(struct vb2_buffer *vb); 238 int (*buf_finish)(struct vb2_buffer *vb); 239 void (*buf_cleanup)(struct vb2_buffer *vb); 240 241 int (*start_streaming)(struct vb2_queue *q, unsigned int count); 242 int (*stop_streaming)(struct vb2_queue *q); 243 244 void (*buf_queue)(struct vb2_buffer *vb); 245 }; 246 247 /** 248 * struct vb2_queue - a videobuf queue 249 * 250 * @type: queue type (see V4L2_BUF_TYPE_* in linux/videodev2.h 251 * @io_modes: supported io methods (see vb2_io_modes enum) 252 * @io_flags: additional io flags (see vb2_fileio_flags enum) 253 * @ops: driver-specific callbacks 254 * @mem_ops: memory allocator specific callbacks 255 * @drv_priv: driver private data 256 * @buf_struct_size: size of the driver-specific buffer structure; 257 * "0" indicates the driver doesn't want to use a custom buffer 258 * structure type, so sizeof(struct vb2_buffer) will is used 259 * 260 * @memory: current memory type used 261 * @bufs: videobuf buffer structures 262 * @num_buffers: number of allocated/used buffers 263 * @queued_list: list of buffers currently queued from userspace 264 * @queued_count: number of buffers owned by the driver 265 * @done_list: list of buffers ready to be dequeued to userspace 266 * @done_lock: lock to protect done_list list 267 * @done_wq: waitqueue for processes waiting for buffers ready to be dequeued 268 * @alloc_ctx: memory type/allocator-specific contexts for each plane 269 * @streaming: current streaming state 270 * @fileio: file io emulator internal data, used only if emulator is active 271 */ 272 struct vb2_queue { 273 enum v4l2_buf_type type; 274 unsigned int io_modes; 275 unsigned int io_flags; 276 277 const struct vb2_ops *ops; 278 const struct vb2_mem_ops *mem_ops; 279 void *drv_priv; 280 unsigned int buf_struct_size; 281 282 /* private: internal use only */ 283 enum v4l2_memory memory; 284 struct vb2_buffer *bufs[VIDEO_MAX_FRAME]; 285 unsigned int num_buffers; 286 287 struct list_head queued_list; 288 289 atomic_t queued_count; 290 struct list_head done_list; 291 spinlock_t done_lock; 292 wait_queue_head_t done_wq; 293 294 void *alloc_ctx[VIDEO_MAX_PLANES]; 295 unsigned int plane_sizes[VIDEO_MAX_PLANES]; 296 297 unsigned int streaming:1; 298 299 struct vb2_fileio_data *fileio; 300 }; 301 302 void *vb2_plane_vaddr(struct vb2_buffer *vb, unsigned int plane_no); 303 void *vb2_plane_cookie(struct vb2_buffer *vb, unsigned int plane_no); 304 305 void vb2_buffer_done(struct vb2_buffer *vb, enum vb2_buffer_state state); 306 int vb2_wait_for_all_buffers(struct vb2_queue *q); 307 308 int vb2_querybuf(struct vb2_queue *q, struct v4l2_buffer *b); 309 int vb2_reqbufs(struct vb2_queue *q, struct v4l2_requestbuffers *req); 310 311 int vb2_create_bufs(struct vb2_queue *q, struct v4l2_create_buffers *create); 312 int vb2_prepare_buf(struct vb2_queue *q, struct v4l2_buffer *b); 313 314 int vb2_queue_init(struct vb2_queue *q); 315 316 void vb2_queue_release(struct vb2_queue *q); 317 318 int vb2_qbuf(struct vb2_queue *q, struct v4l2_buffer *b); 319 int vb2_dqbuf(struct vb2_queue *q, struct v4l2_buffer *b, bool nonblocking); 320 321 int vb2_streamon(struct vb2_queue *q, enum v4l2_buf_type type); 322 int vb2_streamoff(struct vb2_queue *q, enum v4l2_buf_type type); 323 324 int vb2_mmap(struct vb2_queue *q, struct vm_area_struct *vma); 325 #ifndef CONFIG_MMU 326 unsigned long vb2_get_unmapped_area(struct vb2_queue *q, 327 unsigned long addr, 328 unsigned long len, 329 unsigned long pgoff, 330 unsigned long flags); 331 #endif 332 unsigned int vb2_poll(struct vb2_queue *q, struct file *file, poll_table *wait); 333 size_t vb2_read(struct vb2_queue *q, char __user *data, size_t count, 334 loff_t *ppos, int nonblock); 335 size_t vb2_write(struct vb2_queue *q, char __user *data, size_t count, 336 loff_t *ppos, int nonblock); 337 338 /** 339 * vb2_is_streaming() - return streaming status of the queue 340 * @q: videobuf queue 341 */ 342 static inline bool vb2_is_streaming(struct vb2_queue *q) 343 { 344 return q->streaming; 345 } 346 347 /** 348 * vb2_is_busy() - return busy status of the queue 349 * @q: videobuf queue 350 * 351 * This function checks if queue has any buffers allocated. 352 */ 353 static inline bool vb2_is_busy(struct vb2_queue *q) 354 { 355 return (q->num_buffers > 0); 356 } 357 358 /** 359 * vb2_get_drv_priv() - return driver private data associated with the queue 360 * @q: videobuf queue 361 */ 362 static inline void *vb2_get_drv_priv(struct vb2_queue *q) 363 { 364 return q->drv_priv; 365 } 366 367 /** 368 * vb2_set_plane_payload() - set bytesused for the plane plane_no 369 * @vb: buffer for which plane payload should be set 370 * @plane_no: plane number for which payload should be set 371 * @size: payload in bytes 372 */ 373 static inline void vb2_set_plane_payload(struct vb2_buffer *vb, 374 unsigned int plane_no, unsigned long size) 375 { 376 if (plane_no < vb->num_planes) 377 vb->v4l2_planes[plane_no].bytesused = size; 378 } 379 380 /** 381 * vb2_get_plane_payload() - get bytesused for the plane plane_no 382 * @vb: buffer for which plane payload should be set 383 * @plane_no: plane number for which payload should be set 384 * @size: payload in bytes 385 */ 386 static inline unsigned long vb2_get_plane_payload(struct vb2_buffer *vb, 387 unsigned int plane_no) 388 { 389 if (plane_no < vb->num_planes) 390 return vb->v4l2_planes[plane_no].bytesused; 391 return 0; 392 } 393 394 /** 395 * vb2_plane_size() - return plane size in bytes 396 * @vb: buffer for which plane size should be returned 397 * @plane_no: plane number for which size should be returned 398 */ 399 static inline unsigned long 400 vb2_plane_size(struct vb2_buffer *vb, unsigned int plane_no) 401 { 402 if (plane_no < vb->num_planes) 403 return vb->v4l2_planes[plane_no].length; 404 return 0; 405 } 406 407 #endif /* _MEDIA_VIDEOBUF2_CORE_H */ 408