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 */ 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 */ 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 */ 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 */ 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 */ 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 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