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 */ 34 enum vfl_devnode_type { 35 VFL_TYPE_GRABBER = 0, 36 VFL_TYPE_VBI, 37 VFL_TYPE_RADIO, 38 VFL_TYPE_SUBDEV, 39 VFL_TYPE_SDR, 40 VFL_TYPE_TOUCH, 41 VFL_TYPE_MAX /* Shall be the last one */ 42 }; 43 44 /** 45 * enum vfl_direction - Identifies if a &struct video_device corresponds 46 * to a receiver, a transmitter or a mem-to-mem device. 47 * 48 * @VFL_DIR_RX: device is a receiver. 49 * @VFL_DIR_TX: device is a transmitter. 50 * @VFL_DIR_M2M: device is a memory to memory device. 51 * 52 * Note: Ignored if &enum vfl_devnode_type is %VFL_TYPE_SUBDEV. 53 */ 54 enum vfl_devnode_direction { 55 VFL_DIR_RX, 56 VFL_DIR_TX, 57 VFL_DIR_M2M, 58 }; 59 60 struct v4l2_ioctl_callbacks; 61 struct video_device; 62 struct v4l2_device; 63 struct v4l2_ctrl_handler; 64 65 /** 66 * enum v4l2_video_device_flags - Flags used by &struct video_device 67 * 68 * @V4L2_FL_REGISTERED: 69 * indicates that a &struct video_device is registered. 70 * Drivers can clear this flag if they want to block all future 71 * device access. It is cleared by video_unregister_device. 72 * @V4L2_FL_USES_V4L2_FH: 73 * indicates that file->private_data points to &struct v4l2_fh. 74 * This flag is set by the core when v4l2_fh_init() is called. 75 * All new drivers should use it. 76 */ 77 enum v4l2_video_device_flags { 78 V4L2_FL_REGISTERED = 0, 79 V4L2_FL_USES_V4L2_FH = 1, 80 }; 81 82 /* Priority helper functions */ 83 84 /** 85 * struct v4l2_prio_state - stores the priority states 86 * 87 * @prios: array with elements to store the array priorities 88 * 89 * 90 * .. note:: 91 * The size of @prios array matches the number of priority types defined 92 * by enum &v4l2_priority. 93 */ 94 struct v4l2_prio_state { 95 atomic_t prios[4]; 96 }; 97 98 /** 99 * v4l2_prio_init - initializes a struct v4l2_prio_state 100 * 101 * @global: pointer to &struct v4l2_prio_state 102 */ 103 void v4l2_prio_init(struct v4l2_prio_state *global); 104 105 /** 106 * v4l2_prio_change - changes the v4l2 file handler priority 107 * 108 * @global: pointer to the &struct v4l2_prio_state of the device node. 109 * @local: pointer to the desired priority, as defined by enum &v4l2_priority 110 * @new: Priority type requested, as defined by enum &v4l2_priority. 111 * 112 * .. note:: 113 * This function should be used only by the V4L2 core. 114 */ 115 int v4l2_prio_change(struct v4l2_prio_state *global, enum v4l2_priority *local, 116 enum v4l2_priority new); 117 118 /** 119 * v4l2_prio_open - Implements the priority logic for a file handler open 120 * 121 * @global: pointer to the &struct v4l2_prio_state of the device node. 122 * @local: pointer to the desired priority, as defined by enum &v4l2_priority 123 * 124 * .. note:: 125 * This function should be used only by the V4L2 core. 126 */ 127 void v4l2_prio_open(struct v4l2_prio_state *global, enum v4l2_priority *local); 128 129 /** 130 * v4l2_prio_close - Implements the priority logic for a file handler close 131 * 132 * @global: pointer to the &struct v4l2_prio_state of the device node. 133 * @local: priority to be released, as defined by enum &v4l2_priority 134 * 135 * .. note:: 136 * This function should be used only by the V4L2 core. 137 */ 138 void v4l2_prio_close(struct v4l2_prio_state *global, enum v4l2_priority local); 139 140 /** 141 * v4l2_prio_max - Return the maximum priority, as stored at the @global array. 142 * 143 * @global: pointer to the &struct v4l2_prio_state of the device node. 144 * 145 * .. note:: 146 * This function should be used only by the V4L2 core. 147 */ 148 enum v4l2_priority v4l2_prio_max(struct v4l2_prio_state *global); 149 150 /** 151 * v4l2_prio_check - Implements the priority logic for a file handler close 152 * 153 * @global: pointer to the &struct v4l2_prio_state of the device node. 154 * @local: desired priority, as defined by enum &v4l2_priority local 155 * 156 * .. note:: 157 * This function should be used only by the V4L2 core. 158 */ 159 int v4l2_prio_check(struct v4l2_prio_state *global, enum v4l2_priority local); 160 161 /** 162 * struct v4l2_file_operations - fs operations used by a V4L2 device 163 * 164 * @owner: pointer to struct module 165 * @read: operations needed to implement the read() syscall 166 * @write: operations needed to implement the write() syscall 167 * @poll: operations needed to implement the poll() syscall 168 * @unlocked_ioctl: operations needed to implement the ioctl() syscall 169 * @compat_ioctl32: operations needed to implement the ioctl() syscall for 170 * the special case where the Kernel uses 64 bits instructions, but 171 * the userspace uses 32 bits. 172 * @get_unmapped_area: called by the mmap() syscall, used when %!CONFIG_MMU 173 * @mmap: operations needed to implement the mmap() syscall 174 * @open: operations needed to implement the open() syscall 175 * @release: operations needed to implement the release() syscall 176 * 177 * .. note:: 178 * 179 * Those operations are used to implemente the fs struct file_operations 180 * at the V4L2 drivers. The V4L2 core overrides the fs ops with some 181 * extra logic needed by the subsystem. 182 */ 183 struct v4l2_file_operations { 184 struct module *owner; 185 ssize_t (*read) (struct file *, char __user *, size_t, loff_t *); 186 ssize_t (*write) (struct file *, const char __user *, size_t, loff_t *); 187 __poll_t (*poll) (struct file *, struct poll_table_struct *); 188 long (*unlocked_ioctl) (struct file *, unsigned int, unsigned long); 189 #ifdef CONFIG_COMPAT 190 long (*compat_ioctl32) (struct file *, unsigned int, unsigned long); 191 #endif 192 unsigned long (*get_unmapped_area) (struct file *, unsigned long, 193 unsigned long, unsigned long, unsigned long); 194 int (*mmap) (struct file *, struct vm_area_struct *); 195 int (*open) (struct file *); 196 int (*release) (struct file *); 197 }; 198 199 /* 200 * Newer version of video_device, handled by videodev2.c 201 * This version moves redundant code from video device code to 202 * the common handler 203 */ 204 205 /** 206 * struct video_device - Structure used to create and manage the V4L2 device 207 * nodes. 208 * 209 * @entity: &struct media_entity 210 * @intf_devnode: pointer to &struct media_intf_devnode 211 * @pipe: &struct media_pipeline 212 * @fops: pointer to &struct v4l2_file_operations for the video device 213 * @device_caps: device capabilities as used in v4l2_capabilities 214 * @dev: &struct device for the video device 215 * @cdev: character device 216 * @v4l2_dev: pointer to &struct v4l2_device parent 217 * @dev_parent: pointer to &struct device parent 218 * @ctrl_handler: Control handler associated with this device node. 219 * May be NULL. 220 * @queue: &struct vb2_queue associated with this device node. May be NULL. 221 * @prio: pointer to &struct v4l2_prio_state with device's Priority state. 222 * If NULL, then v4l2_dev->prio will be used. 223 * @name: video device name 224 * @vfl_type: V4L device type, as defined by &enum vfl_devnode_type 225 * @vfl_dir: V4L receiver, transmitter or m2m 226 * @minor: device node 'minor'. It is set to -1 if the registration failed 227 * @num: number of the video device node 228 * @flags: video device flags. Use bitops to set/clear/test flags. 229 * Contains a set of &enum v4l2_video_device_flags. 230 * @index: attribute to differentiate multiple indices on one physical device 231 * @fh_lock: Lock for all v4l2_fhs 232 * @fh_list: List of &struct v4l2_fh 233 * @dev_debug: Internal device debug flags, not for use by drivers 234 * @tvnorms: Supported tv norms 235 * 236 * @release: video device release() callback 237 * @ioctl_ops: pointer to &struct v4l2_ioctl_ops with ioctl callbacks 238 * 239 * @valid_ioctls: bitmap with the valid ioctls for this device 240 * @disable_locking: bitmap with the ioctls that don't require locking 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 DECLARE_BITMAP(disable_locking, BASE_VIDIOC_PRIVATE); 294 struct mutex *lock; 295 }; 296 297 /** 298 * media_entity_to_video_device - Returns a &struct video_device from 299 * the &struct media_entity embedded on it. 300 * 301 * @__entity: pointer to &struct media_entity 302 */ 303 #define media_entity_to_video_device(__entity) \ 304 container_of(__entity, struct video_device, entity) 305 306 /** 307 * to_video_device - Returns a &struct video_device from the 308 * &struct device embedded on it. 309 * 310 * @cd: pointer to &struct device 311 */ 312 #define to_video_device(cd) container_of(cd, struct video_device, dev) 313 314 /** 315 * __video_register_device - register video4linux devices 316 * 317 * @vdev: struct video_device to register 318 * @type: type of device to register, as defined by &enum vfl_devnode_type 319 * @nr: which device node number is desired: 320 * (0 == /dev/video0, 1 == /dev/video1, ..., -1 == first free) 321 * @warn_if_nr_in_use: warn if the desired device node number 322 * was already in use and another number was chosen instead. 323 * @owner: module that owns the video device node 324 * 325 * The registration code assigns minor numbers and device node numbers 326 * based on the requested type and registers the new device node with 327 * the kernel. 328 * 329 * This function assumes that struct video_device was zeroed when it 330 * was allocated and does not contain any stale date. 331 * 332 * An error is returned if no free minor or device node number could be 333 * found, or if the registration of the device node failed. 334 * 335 * Returns 0 on success. 336 * 337 * .. note:: 338 * 339 * This function is meant to be used only inside the V4L2 core. 340 * Drivers should use video_register_device() or 341 * video_register_device_no_warn(). 342 */ 343 int __must_check __video_register_device(struct video_device *vdev, 344 enum vfl_devnode_type type, 345 int nr, int warn_if_nr_in_use, 346 struct module *owner); 347 348 /** 349 * video_register_device - register video4linux devices 350 * 351 * @vdev: struct video_device to register 352 * @type: type of device to register, as defined by &enum vfl_devnode_type 353 * @nr: which device node number is desired: 354 * (0 == /dev/video0, 1 == /dev/video1, ..., -1 == first free) 355 * 356 * Internally, it calls __video_register_device(). Please see its 357 * documentation for more details. 358 * 359 * .. note:: 360 * if video_register_device fails, the release() callback of 361 * &struct video_device structure is *not* called, so the caller 362 * is responsible for freeing any data. Usually that means that 363 * you video_device_release() should be called on failure. 364 */ 365 static inline int __must_check video_register_device(struct video_device *vdev, 366 enum vfl_devnode_type type, 367 int nr) 368 { 369 return __video_register_device(vdev, type, nr, 1, vdev->fops->owner); 370 } 371 372 /** 373 * video_register_device_no_warn - register video4linux devices 374 * 375 * @vdev: struct video_device to register 376 * @type: type of device to register, as defined by &enum vfl_devnode_type 377 * @nr: which device node number is desired: 378 * (0 == /dev/video0, 1 == /dev/video1, ..., -1 == first free) 379 * 380 * This function is identical to video_register_device() except that no 381 * warning is issued if the desired device node number was already in use. 382 * 383 * Internally, it calls __video_register_device(). Please see its 384 * documentation for more details. 385 * 386 * .. note:: 387 * if video_register_device fails, the release() callback of 388 * &struct video_device structure is *not* called, so the caller 389 * is responsible for freeing any data. Usually that means that 390 * you video_device_release() should be called on failure. 391 */ 392 static inline int __must_check 393 video_register_device_no_warn(struct video_device *vdev, 394 enum vfl_devnode_type type, int nr) 395 { 396 return __video_register_device(vdev, type, nr, 0, vdev->fops->owner); 397 } 398 399 /** 400 * video_unregister_device - Unregister video devices. 401 * 402 * @vdev: &struct video_device to register 403 * 404 * Does nothing if vdev == NULL or if video_is_registered() returns false. 405 */ 406 void video_unregister_device(struct video_device *vdev); 407 408 /** 409 * video_device_alloc - helper function to alloc &struct video_device 410 * 411 * Returns NULL if %-ENOMEM or a &struct video_device on success. 412 */ 413 struct video_device * __must_check video_device_alloc(void); 414 415 /** 416 * video_device_release - helper function to release &struct video_device 417 * 418 * @vdev: pointer to &struct video_device 419 * 420 * Can also be used for video_device->release\(\). 421 */ 422 void video_device_release(struct video_device *vdev); 423 424 /** 425 * video_device_release_empty - helper function to implement the 426 * video_device->release\(\) callback. 427 * 428 * @vdev: pointer to &struct video_device 429 * 430 * This release function does nothing. 431 * 432 * It should be used when the video_device is a static global struct. 433 * 434 * .. note:: 435 * Having a static video_device is a dubious construction at best. 436 */ 437 void video_device_release_empty(struct video_device *vdev); 438 439 /** 440 * v4l2_is_known_ioctl - Checks if a given cmd is a known V4L ioctl 441 * 442 * @cmd: ioctl command 443 * 444 * returns true if cmd is a known V4L2 ioctl 445 */ 446 bool v4l2_is_known_ioctl(unsigned int cmd); 447 448 /** v4l2_disable_ioctl_locking - mark that a given command 449 * shouldn't use core locking 450 * 451 * @vdev: pointer to &struct video_device 452 * @cmd: ioctl command 453 */ 454 static inline void v4l2_disable_ioctl_locking(struct video_device *vdev, 455 unsigned int cmd) 456 { 457 if (_IOC_NR(cmd) < BASE_VIDIOC_PRIVATE) 458 set_bit(_IOC_NR(cmd), vdev->disable_locking); 459 } 460 461 /** 462 * v4l2_disable_ioctl- mark that a given command isn't implemented. 463 * shouldn't use core locking 464 * 465 * @vdev: pointer to &struct video_device 466 * @cmd: ioctl command 467 * 468 * This function allows drivers to provide just one v4l2_ioctl_ops struct, but 469 * disable ioctls based on the specific card that is actually found. 470 * 471 * .. note:: 472 * 473 * This must be called before video_register_device. 474 * See also the comments for determine_valid_ioctls(). 475 */ 476 static inline void v4l2_disable_ioctl(struct video_device *vdev, 477 unsigned int cmd) 478 { 479 if (_IOC_NR(cmd) < BASE_VIDIOC_PRIVATE) 480 set_bit(_IOC_NR(cmd), vdev->valid_ioctls); 481 } 482 483 /** 484 * video_get_drvdata - gets private data from &struct video_device. 485 * 486 * @vdev: pointer to &struct video_device 487 * 488 * returns a pointer to the private data 489 */ 490 static inline void *video_get_drvdata(struct video_device *vdev) 491 { 492 return dev_get_drvdata(&vdev->dev); 493 } 494 495 /** 496 * video_set_drvdata - sets private data from &struct video_device. 497 * 498 * @vdev: pointer to &struct video_device 499 * @data: private data pointer 500 */ 501 static inline void video_set_drvdata(struct video_device *vdev, void *data) 502 { 503 dev_set_drvdata(&vdev->dev, data); 504 } 505 506 /** 507 * video_devdata - gets &struct video_device from struct file. 508 * 509 * @file: pointer to struct file 510 */ 511 struct video_device *video_devdata(struct file *file); 512 513 /** 514 * video_drvdata - gets private data from &struct video_device using the 515 * struct file. 516 * 517 * @file: pointer to struct file 518 * 519 * This is function combines both video_get_drvdata() and video_devdata() 520 * as this is used very often. 521 */ 522 static inline void *video_drvdata(struct file *file) 523 { 524 return video_get_drvdata(video_devdata(file)); 525 } 526 527 /** 528 * video_device_node_name - returns the video device name 529 * 530 * @vdev: pointer to &struct video_device 531 * 532 * Returns the device name string 533 */ 534 static inline const char *video_device_node_name(struct video_device *vdev) 535 { 536 return dev_name(&vdev->dev); 537 } 538 539 /** 540 * video_is_registered - returns true if the &struct video_device is registered. 541 * 542 * 543 * @vdev: pointer to &struct video_device 544 */ 545 static inline int video_is_registered(struct video_device *vdev) 546 { 547 return test_bit(V4L2_FL_REGISTERED, &vdev->flags); 548 } 549 550 #endif /* _V4L2_DEV_H */ 551