1 /* SPDX-License-Identifier: GPL-2.0 */ 2 /* 3 * 4 * V 4 L 2 D R I V E R H E L P E R A P I 5 * 6 * Moved from videodev2.h 7 * 8 * Some commonly needed functions for drivers (v4l2-common.o module) 9 */ 10 #ifndef _V4L2_DEV_H 11 #define _V4L2_DEV_H 12 13 #include <linux/poll.h> 14 #include <linux/fs.h> 15 #include <linux/device.h> 16 #include <linux/cdev.h> 17 #include <linux/mutex.h> 18 #include <linux/videodev2.h> 19 20 #include <media/media-entity.h> 21 22 #define VIDEO_MAJOR 81 23 24 /** 25 * enum vfl_devnode_type - type of V4L2 device node 26 * 27 * @VFL_TYPE_GRABBER: for video input/output devices 28 * @VFL_TYPE_VBI: for vertical blank data (i.e. closed captions, teletext) 29 * @VFL_TYPE_RADIO: for radio tuners 30 * @VFL_TYPE_SUBDEV: for V4L2 subdevices 31 * @VFL_TYPE_SDR: for Software Defined Radio tuners 32 * @VFL_TYPE_TOUCH: for touch sensors 33 * @VFL_TYPE_MAX: number of VFL types, must always be last in the enum 34 */ 35 enum vfl_devnode_type { 36 VFL_TYPE_GRABBER = 0, 37 VFL_TYPE_VBI, 38 VFL_TYPE_RADIO, 39 VFL_TYPE_SUBDEV, 40 VFL_TYPE_SDR, 41 VFL_TYPE_TOUCH, 42 VFL_TYPE_MAX /* Shall be the last one */ 43 }; 44 45 /** 46 * enum vfl_direction - Identifies if a &struct video_device corresponds 47 * to a receiver, a transmitter or a mem-to-mem device. 48 * 49 * @VFL_DIR_RX: device is a receiver. 50 * @VFL_DIR_TX: device is a transmitter. 51 * @VFL_DIR_M2M: device is a memory to memory device. 52 * 53 * Note: Ignored if &enum vfl_devnode_type is %VFL_TYPE_SUBDEV. 54 */ 55 enum vfl_devnode_direction { 56 VFL_DIR_RX, 57 VFL_DIR_TX, 58 VFL_DIR_M2M, 59 }; 60 61 struct v4l2_ioctl_callbacks; 62 struct video_device; 63 struct v4l2_device; 64 struct v4l2_ctrl_handler; 65 66 /** 67 * enum v4l2_video_device_flags - Flags used by &struct video_device 68 * 69 * @V4L2_FL_REGISTERED: 70 * indicates that a &struct video_device is registered. 71 * Drivers can clear this flag if they want to block all future 72 * device access. It is cleared by video_unregister_device. 73 * @V4L2_FL_USES_V4L2_FH: 74 * indicates that file->private_data points to &struct v4l2_fh. 75 * This flag is set by the core when v4l2_fh_init() is called. 76 * All new drivers should use it. 77 */ 78 enum v4l2_video_device_flags { 79 V4L2_FL_REGISTERED = 0, 80 V4L2_FL_USES_V4L2_FH = 1, 81 }; 82 83 /* Priority helper functions */ 84 85 /** 86 * struct v4l2_prio_state - stores the priority states 87 * 88 * @prios: array with elements to store the array priorities 89 * 90 * 91 * .. note:: 92 * The size of @prios array matches the number of priority types defined 93 * by enum &v4l2_priority. 94 */ 95 struct v4l2_prio_state { 96 atomic_t prios[4]; 97 }; 98 99 /** 100 * v4l2_prio_init - initializes a struct v4l2_prio_state 101 * 102 * @global: pointer to &struct v4l2_prio_state 103 */ 104 void v4l2_prio_init(struct v4l2_prio_state *global); 105 106 /** 107 * v4l2_prio_change - changes the v4l2 file handler priority 108 * 109 * @global: pointer to the &struct v4l2_prio_state of the device node. 110 * @local: pointer to the desired priority, as defined by enum &v4l2_priority 111 * @new: Priority type requested, as defined by enum &v4l2_priority. 112 * 113 * .. note:: 114 * This function should be used only by the V4L2 core. 115 */ 116 int v4l2_prio_change(struct v4l2_prio_state *global, enum v4l2_priority *local, 117 enum v4l2_priority new); 118 119 /** 120 * v4l2_prio_open - Implements the priority logic for a file handler open 121 * 122 * @global: pointer to the &struct v4l2_prio_state of the device node. 123 * @local: pointer to the desired priority, as defined by enum &v4l2_priority 124 * 125 * .. note:: 126 * This function should be used only by the V4L2 core. 127 */ 128 void v4l2_prio_open(struct v4l2_prio_state *global, enum v4l2_priority *local); 129 130 /** 131 * v4l2_prio_close - Implements the priority logic for a file handler close 132 * 133 * @global: pointer to the &struct v4l2_prio_state of the device node. 134 * @local: priority to be released, as defined by enum &v4l2_priority 135 * 136 * .. note:: 137 * This function should be used only by the V4L2 core. 138 */ 139 void v4l2_prio_close(struct v4l2_prio_state *global, enum v4l2_priority local); 140 141 /** 142 * v4l2_prio_max - Return the maximum priority, as stored at the @global array. 143 * 144 * @global: pointer to the &struct v4l2_prio_state of the device node. 145 * 146 * .. note:: 147 * This function should be used only by the V4L2 core. 148 */ 149 enum v4l2_priority v4l2_prio_max(struct v4l2_prio_state *global); 150 151 /** 152 * v4l2_prio_check - Implements the priority logic for a file handler close 153 * 154 * @global: pointer to the &struct v4l2_prio_state of the device node. 155 * @local: desired priority, as defined by enum &v4l2_priority local 156 * 157 * .. note:: 158 * This function should be used only by the V4L2 core. 159 */ 160 int v4l2_prio_check(struct v4l2_prio_state *global, enum v4l2_priority local); 161 162 /** 163 * struct v4l2_file_operations - fs operations used by a V4L2 device 164 * 165 * @owner: pointer to struct module 166 * @read: operations needed to implement the read() syscall 167 * @write: operations needed to implement the write() syscall 168 * @poll: operations needed to implement the poll() syscall 169 * @unlocked_ioctl: operations needed to implement the ioctl() syscall 170 * @compat_ioctl32: operations needed to implement the ioctl() syscall for 171 * the special case where the Kernel uses 64 bits instructions, but 172 * the userspace uses 32 bits. 173 * @get_unmapped_area: called by the mmap() syscall, used when %!CONFIG_MMU 174 * @mmap: operations needed to implement the mmap() syscall 175 * @open: operations needed to implement the open() syscall 176 * @release: operations needed to implement the release() syscall 177 * 178 * .. note:: 179 * 180 * Those operations are used to implemente the fs struct file_operations 181 * at the V4L2 drivers. The V4L2 core overrides the fs ops with some 182 * extra logic needed by the subsystem. 183 */ 184 struct v4l2_file_operations { 185 struct module *owner; 186 ssize_t (*read) (struct file *, char __user *, size_t, loff_t *); 187 ssize_t (*write) (struct file *, const char __user *, size_t, loff_t *); 188 __poll_t (*poll) (struct file *, struct poll_table_struct *); 189 long (*unlocked_ioctl) (struct file *, unsigned int, unsigned long); 190 #ifdef CONFIG_COMPAT 191 long (*compat_ioctl32) (struct file *, unsigned int, unsigned long); 192 #endif 193 unsigned long (*get_unmapped_area) (struct file *, unsigned long, 194 unsigned long, unsigned long, unsigned long); 195 int (*mmap) (struct file *, struct vm_area_struct *); 196 int (*open) (struct file *); 197 int (*release) (struct file *); 198 }; 199 200 /* 201 * Newer version of video_device, handled by videodev2.c 202 * This version moves redundant code from video device code to 203 * the common handler 204 */ 205 206 /** 207 * struct video_device - Structure used to create and manage the V4L2 device 208 * nodes. 209 * 210 * @entity: &struct media_entity 211 * @intf_devnode: pointer to &struct media_intf_devnode 212 * @pipe: &struct media_pipeline 213 * @fops: pointer to &struct v4l2_file_operations for the video device 214 * @device_caps: device capabilities as used in v4l2_capabilities 215 * @dev: &struct device for the video device 216 * @cdev: character device 217 * @v4l2_dev: pointer to &struct v4l2_device parent 218 * @dev_parent: pointer to &struct device parent 219 * @ctrl_handler: Control handler associated with this device node. 220 * May be NULL. 221 * @queue: &struct vb2_queue associated with this device node. May be NULL. 222 * @prio: pointer to &struct v4l2_prio_state with device's Priority state. 223 * If NULL, then v4l2_dev->prio will be used. 224 * @name: video device name 225 * @vfl_type: V4L device type, as defined by &enum vfl_devnode_type 226 * @vfl_dir: V4L receiver, transmitter or m2m 227 * @minor: device node 'minor'. It is set to -1 if the registration failed 228 * @num: number of the video device node 229 * @flags: video device flags. Use bitops to set/clear/test flags. 230 * Contains a set of &enum v4l2_video_device_flags. 231 * @index: attribute to differentiate multiple indices on one physical device 232 * @fh_lock: Lock for all v4l2_fhs 233 * @fh_list: List of &struct v4l2_fh 234 * @dev_debug: Internal device debug flags, not for use by drivers 235 * @tvnorms: Supported tv norms 236 * 237 * @release: video device release() callback 238 * @ioctl_ops: pointer to &struct v4l2_ioctl_ops with ioctl callbacks 239 * 240 * @valid_ioctls: bitmap with the valid ioctls for this device 241 * @lock: pointer to &struct mutex serialization lock 242 * 243 * .. note:: 244 * Only set @dev_parent if that can't be deduced from @v4l2_dev. 245 */ 246 247 struct video_device 248 { 249 #if defined(CONFIG_MEDIA_CONTROLLER) 250 struct media_entity entity; 251 struct media_intf_devnode *intf_devnode; 252 struct media_pipeline pipe; 253 #endif 254 const struct v4l2_file_operations *fops; 255 256 u32 device_caps; 257 258 /* sysfs */ 259 struct device dev; 260 struct cdev *cdev; 261 262 struct v4l2_device *v4l2_dev; 263 struct device *dev_parent; 264 265 struct v4l2_ctrl_handler *ctrl_handler; 266 267 struct vb2_queue *queue; 268 269 struct v4l2_prio_state *prio; 270 271 /* device info */ 272 char name[32]; 273 enum vfl_devnode_type vfl_type; 274 enum vfl_devnode_direction vfl_dir; 275 int minor; 276 u16 num; 277 unsigned long flags; 278 int index; 279 280 /* V4L2 file handles */ 281 spinlock_t fh_lock; 282 struct list_head fh_list; 283 284 int dev_debug; 285 286 v4l2_std_id tvnorms; 287 288 /* callbacks */ 289 void (*release)(struct video_device *vdev); 290 const struct v4l2_ioctl_ops *ioctl_ops; 291 DECLARE_BITMAP(valid_ioctls, BASE_VIDIOC_PRIVATE); 292 293 struct mutex *lock; 294 }; 295 296 /** 297 * media_entity_to_video_device - Returns a &struct video_device from 298 * the &struct media_entity embedded on it. 299 * 300 * @__entity: pointer to &struct media_entity 301 */ 302 #define media_entity_to_video_device(__entity) \ 303 container_of(__entity, struct video_device, entity) 304 305 /** 306 * to_video_device - Returns a &struct video_device from the 307 * &struct device embedded on it. 308 * 309 * @cd: pointer to &struct device 310 */ 311 #define to_video_device(cd) container_of(cd, struct video_device, dev) 312 313 /** 314 * __video_register_device - register video4linux devices 315 * 316 * @vdev: struct video_device to register 317 * @type: type of device to register, as defined by &enum vfl_devnode_type 318 * @nr: which device node number is desired: 319 * (0 == /dev/video0, 1 == /dev/video1, ..., -1 == first free) 320 * @warn_if_nr_in_use: warn if the desired device node number 321 * was already in use and another number was chosen instead. 322 * @owner: module that owns the video device node 323 * 324 * The registration code assigns minor numbers and device node numbers 325 * based on the requested type and registers the new device node with 326 * the kernel. 327 * 328 * This function assumes that struct video_device was zeroed when it 329 * was allocated and does not contain any stale date. 330 * 331 * An error is returned if no free minor or device node number could be 332 * found, or if the registration of the device node failed. 333 * 334 * Returns 0 on success. 335 * 336 * .. note:: 337 * 338 * This function is meant to be used only inside the V4L2 core. 339 * Drivers should use video_register_device() or 340 * video_register_device_no_warn(). 341 */ 342 int __must_check __video_register_device(struct video_device *vdev, 343 enum vfl_devnode_type type, 344 int nr, int warn_if_nr_in_use, 345 struct module *owner); 346 347 /** 348 * video_register_device - register video4linux devices 349 * 350 * @vdev: struct video_device to register 351 * @type: type of device to register, as defined by &enum vfl_devnode_type 352 * @nr: which device node number is desired: 353 * (0 == /dev/video0, 1 == /dev/video1, ..., -1 == first free) 354 * 355 * Internally, it calls __video_register_device(). Please see its 356 * documentation for more details. 357 * 358 * .. note:: 359 * if video_register_device fails, the release() callback of 360 * &struct video_device structure is *not* called, so the caller 361 * is responsible for freeing any data. Usually that means that 362 * you video_device_release() should be called on failure. 363 */ 364 static inline int __must_check video_register_device(struct video_device *vdev, 365 enum vfl_devnode_type type, 366 int nr) 367 { 368 return __video_register_device(vdev, type, nr, 1, vdev->fops->owner); 369 } 370 371 /** 372 * video_register_device_no_warn - register video4linux devices 373 * 374 * @vdev: struct video_device to register 375 * @type: type of device to register, as defined by &enum vfl_devnode_type 376 * @nr: which device node number is desired: 377 * (0 == /dev/video0, 1 == /dev/video1, ..., -1 == first free) 378 * 379 * This function is identical to video_register_device() except that no 380 * warning is issued if the desired device node number was already in use. 381 * 382 * Internally, it calls __video_register_device(). Please see its 383 * documentation for more details. 384 * 385 * .. note:: 386 * if video_register_device fails, the release() callback of 387 * &struct video_device structure is *not* called, so the caller 388 * is responsible for freeing any data. Usually that means that 389 * you video_device_release() should be called on failure. 390 */ 391 static inline int __must_check 392 video_register_device_no_warn(struct video_device *vdev, 393 enum vfl_devnode_type type, int nr) 394 { 395 return __video_register_device(vdev, type, nr, 0, vdev->fops->owner); 396 } 397 398 /** 399 * video_unregister_device - Unregister video devices. 400 * 401 * @vdev: &struct video_device to register 402 * 403 * Does nothing if vdev == NULL or if video_is_registered() returns false. 404 */ 405 void video_unregister_device(struct video_device *vdev); 406 407 /** 408 * video_device_alloc - helper function to alloc &struct video_device 409 * 410 * Returns NULL if %-ENOMEM or a &struct video_device on success. 411 */ 412 struct video_device * __must_check video_device_alloc(void); 413 414 /** 415 * video_device_release - helper function to release &struct video_device 416 * 417 * @vdev: pointer to &struct video_device 418 * 419 * Can also be used for video_device->release\(\). 420 */ 421 void video_device_release(struct video_device *vdev); 422 423 /** 424 * video_device_release_empty - helper function to implement the 425 * video_device->release\(\) callback. 426 * 427 * @vdev: pointer to &struct video_device 428 * 429 * This release function does nothing. 430 * 431 * It should be used when the video_device is a static global struct. 432 * 433 * .. note:: 434 * Having a static video_device is a dubious construction at best. 435 */ 436 void video_device_release_empty(struct video_device *vdev); 437 438 /** 439 * v4l2_disable_ioctl- mark that a given command isn't implemented. 440 * shouldn't use core locking 441 * 442 * @vdev: pointer to &struct video_device 443 * @cmd: ioctl command 444 * 445 * This function allows drivers to provide just one v4l2_ioctl_ops struct, but 446 * disable ioctls based on the specific card that is actually found. 447 * 448 * .. note:: 449 * 450 * This must be called before video_register_device. 451 * See also the comments for determine_valid_ioctls(). 452 */ 453 static inline void v4l2_disable_ioctl(struct video_device *vdev, 454 unsigned int cmd) 455 { 456 if (_IOC_NR(cmd) < BASE_VIDIOC_PRIVATE) 457 set_bit(_IOC_NR(cmd), vdev->valid_ioctls); 458 } 459 460 /** 461 * video_get_drvdata - gets private data from &struct video_device. 462 * 463 * @vdev: pointer to &struct video_device 464 * 465 * returns a pointer to the private data 466 */ 467 static inline void *video_get_drvdata(struct video_device *vdev) 468 { 469 return dev_get_drvdata(&vdev->dev); 470 } 471 472 /** 473 * video_set_drvdata - sets private data from &struct video_device. 474 * 475 * @vdev: pointer to &struct video_device 476 * @data: private data pointer 477 */ 478 static inline void video_set_drvdata(struct video_device *vdev, void *data) 479 { 480 dev_set_drvdata(&vdev->dev, data); 481 } 482 483 /** 484 * video_devdata - gets &struct video_device from struct file. 485 * 486 * @file: pointer to struct file 487 */ 488 struct video_device *video_devdata(struct file *file); 489 490 /** 491 * video_drvdata - gets private data from &struct video_device using the 492 * struct file. 493 * 494 * @file: pointer to struct file 495 * 496 * This is function combines both video_get_drvdata() and video_devdata() 497 * as this is used very often. 498 */ 499 static inline void *video_drvdata(struct file *file) 500 { 501 return video_get_drvdata(video_devdata(file)); 502 } 503 504 /** 505 * video_device_node_name - returns the video device name 506 * 507 * @vdev: pointer to &struct video_device 508 * 509 * Returns the device name string 510 */ 511 static inline const char *video_device_node_name(struct video_device *vdev) 512 { 513 return dev_name(&vdev->dev); 514 } 515 516 /** 517 * video_is_registered - returns true if the &struct video_device is registered. 518 * 519 * 520 * @vdev: pointer to &struct video_device 521 */ 522 static inline int video_is_registered(struct video_device *vdev) 523 { 524 return test_bit(V4L2_FL_REGISTERED, &vdev->flags); 525 } 526 527 #endif /* _V4L2_DEV_H */ 528