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 * @disable_locking: bitmap with the ioctls that don't require locking 242 * @lock: pointer to &struct mutex serialization lock 243 * 244 * .. note:: 245 * Only set @dev_parent if that can't be deduced from @v4l2_dev. 246 */ 247 248 struct video_device 249 { 250 #if defined(CONFIG_MEDIA_CONTROLLER) 251 struct media_entity entity; 252 struct media_intf_devnode *intf_devnode; 253 struct media_pipeline pipe; 254 #endif 255 const struct v4l2_file_operations *fops; 256 257 u32 device_caps; 258 259 /* sysfs */ 260 struct device dev; 261 struct cdev *cdev; 262 263 struct v4l2_device *v4l2_dev; 264 struct device *dev_parent; 265 266 struct v4l2_ctrl_handler *ctrl_handler; 267 268 struct vb2_queue *queue; 269 270 struct v4l2_prio_state *prio; 271 272 /* device info */ 273 char name[32]; 274 enum vfl_devnode_type vfl_type; 275 enum vfl_devnode_direction vfl_dir; 276 int minor; 277 u16 num; 278 unsigned long flags; 279 int index; 280 281 /* V4L2 file handles */ 282 spinlock_t fh_lock; 283 struct list_head fh_list; 284 285 int dev_debug; 286 287 v4l2_std_id tvnorms; 288 289 /* callbacks */ 290 void (*release)(struct video_device *vdev); 291 const struct v4l2_ioctl_ops *ioctl_ops; 292 DECLARE_BITMAP(valid_ioctls, BASE_VIDIOC_PRIVATE); 293 294 DECLARE_BITMAP(disable_locking, BASE_VIDIOC_PRIVATE); 295 struct mutex *lock; 296 }; 297 298 /** 299 * media_entity_to_video_device - Returns a &struct video_device from 300 * the &struct media_entity embedded on it. 301 * 302 * @__entity: pointer to &struct media_entity 303 */ 304 #define media_entity_to_video_device(__entity) \ 305 container_of(__entity, struct video_device, entity) 306 307 /** 308 * to_video_device - Returns a &struct video_device from the 309 * &struct device embedded on it. 310 * 311 * @cd: pointer to &struct device 312 */ 313 #define to_video_device(cd) container_of(cd, struct video_device, dev) 314 315 /** 316 * __video_register_device - register video4linux devices 317 * 318 * @vdev: struct video_device to register 319 * @type: type of device to register, as defined by &enum vfl_devnode_type 320 * @nr: which device node number is desired: 321 * (0 == /dev/video0, 1 == /dev/video1, ..., -1 == first free) 322 * @warn_if_nr_in_use: warn if the desired device node number 323 * was already in use and another number was chosen instead. 324 * @owner: module that owns the video device node 325 * 326 * The registration code assigns minor numbers and device node numbers 327 * based on the requested type and registers the new device node with 328 * the kernel. 329 * 330 * This function assumes that struct video_device was zeroed when it 331 * was allocated and does not contain any stale date. 332 * 333 * An error is returned if no free minor or device node number could be 334 * found, or if the registration of the device node failed. 335 * 336 * Returns 0 on success. 337 * 338 * .. note:: 339 * 340 * This function is meant to be used only inside the V4L2 core. 341 * Drivers should use video_register_device() or 342 * video_register_device_no_warn(). 343 */ 344 int __must_check __video_register_device(struct video_device *vdev, 345 enum vfl_devnode_type type, 346 int nr, int warn_if_nr_in_use, 347 struct module *owner); 348 349 /** 350 * video_register_device - register video4linux devices 351 * 352 * @vdev: struct video_device to register 353 * @type: type of device to register, as defined by &enum vfl_devnode_type 354 * @nr: which device node number is desired: 355 * (0 == /dev/video0, 1 == /dev/video1, ..., -1 == first free) 356 * 357 * Internally, it calls __video_register_device(). Please see its 358 * documentation for more details. 359 * 360 * .. note:: 361 * if video_register_device fails, the release() callback of 362 * &struct video_device structure is *not* called, so the caller 363 * is responsible for freeing any data. Usually that means that 364 * you video_device_release() should be called on failure. 365 */ 366 static inline int __must_check video_register_device(struct video_device *vdev, 367 enum vfl_devnode_type type, 368 int nr) 369 { 370 return __video_register_device(vdev, type, nr, 1, vdev->fops->owner); 371 } 372 373 /** 374 * video_register_device_no_warn - register video4linux devices 375 * 376 * @vdev: struct video_device to register 377 * @type: type of device to register, as defined by &enum vfl_devnode_type 378 * @nr: which device node number is desired: 379 * (0 == /dev/video0, 1 == /dev/video1, ..., -1 == first free) 380 * 381 * This function is identical to video_register_device() except that no 382 * warning is issued if the desired device node number was already in use. 383 * 384 * Internally, it calls __video_register_device(). Please see its 385 * documentation for more details. 386 * 387 * .. note:: 388 * if video_register_device fails, the release() callback of 389 * &struct video_device structure is *not* called, so the caller 390 * is responsible for freeing any data. Usually that means that 391 * you video_device_release() should be called on failure. 392 */ 393 static inline int __must_check 394 video_register_device_no_warn(struct video_device *vdev, 395 enum vfl_devnode_type type, int nr) 396 { 397 return __video_register_device(vdev, type, nr, 0, vdev->fops->owner); 398 } 399 400 /** 401 * video_unregister_device - Unregister video devices. 402 * 403 * @vdev: &struct video_device to register 404 * 405 * Does nothing if vdev == NULL or if video_is_registered() returns false. 406 */ 407 void video_unregister_device(struct video_device *vdev); 408 409 /** 410 * video_device_alloc - helper function to alloc &struct video_device 411 * 412 * Returns NULL if %-ENOMEM or a &struct video_device on success. 413 */ 414 struct video_device * __must_check video_device_alloc(void); 415 416 /** 417 * video_device_release - helper function to release &struct video_device 418 * 419 * @vdev: pointer to &struct video_device 420 * 421 * Can also be used for video_device->release\(\). 422 */ 423 void video_device_release(struct video_device *vdev); 424 425 /** 426 * video_device_release_empty - helper function to implement the 427 * video_device->release\(\) callback. 428 * 429 * @vdev: pointer to &struct video_device 430 * 431 * This release function does nothing. 432 * 433 * It should be used when the video_device is a static global struct. 434 * 435 * .. note:: 436 * Having a static video_device is a dubious construction at best. 437 */ 438 void video_device_release_empty(struct video_device *vdev); 439 440 /** 441 * v4l2_is_known_ioctl - Checks if a given cmd is a known V4L ioctl 442 * 443 * @cmd: ioctl command 444 * 445 * returns true if cmd is a known V4L2 ioctl 446 */ 447 bool v4l2_is_known_ioctl(unsigned int cmd); 448 449 /** v4l2_disable_ioctl_locking - mark that a given command 450 * shouldn't use core locking 451 * 452 * @vdev: pointer to &struct video_device 453 * @cmd: ioctl command 454 */ 455 static inline void v4l2_disable_ioctl_locking(struct video_device *vdev, 456 unsigned int cmd) 457 { 458 if (_IOC_NR(cmd) < BASE_VIDIOC_PRIVATE) 459 set_bit(_IOC_NR(cmd), vdev->disable_locking); 460 } 461 462 /** 463 * v4l2_disable_ioctl- mark that a given command isn't implemented. 464 * shouldn't use core locking 465 * 466 * @vdev: pointer to &struct video_device 467 * @cmd: ioctl command 468 * 469 * This function allows drivers to provide just one v4l2_ioctl_ops struct, but 470 * disable ioctls based on the specific card that is actually found. 471 * 472 * .. note:: 473 * 474 * This must be called before video_register_device. 475 * See also the comments for determine_valid_ioctls(). 476 */ 477 static inline void v4l2_disable_ioctl(struct video_device *vdev, 478 unsigned int cmd) 479 { 480 if (_IOC_NR(cmd) < BASE_VIDIOC_PRIVATE) 481 set_bit(_IOC_NR(cmd), vdev->valid_ioctls); 482 } 483 484 /** 485 * video_get_drvdata - gets private data from &struct video_device. 486 * 487 * @vdev: pointer to &struct video_device 488 * 489 * returns a pointer to the private data 490 */ 491 static inline void *video_get_drvdata(struct video_device *vdev) 492 { 493 return dev_get_drvdata(&vdev->dev); 494 } 495 496 /** 497 * video_set_drvdata - sets private data from &struct video_device. 498 * 499 * @vdev: pointer to &struct video_device 500 * @data: private data pointer 501 */ 502 static inline void video_set_drvdata(struct video_device *vdev, void *data) 503 { 504 dev_set_drvdata(&vdev->dev, data); 505 } 506 507 /** 508 * video_devdata - gets &struct video_device from struct file. 509 * 510 * @file: pointer to struct file 511 */ 512 struct video_device *video_devdata(struct file *file); 513 514 /** 515 * video_drvdata - gets private data from &struct video_device using the 516 * struct file. 517 * 518 * @file: pointer to struct file 519 * 520 * This is function combines both video_get_drvdata() and video_devdata() 521 * as this is used very often. 522 */ 523 static inline void *video_drvdata(struct file *file) 524 { 525 return video_get_drvdata(video_devdata(file)); 526 } 527 528 /** 529 * video_device_node_name - returns the video device name 530 * 531 * @vdev: pointer to &struct video_device 532 * 533 * Returns the device name string 534 */ 535 static inline const char *video_device_node_name(struct video_device *vdev) 536 { 537 return dev_name(&vdev->dev); 538 } 539 540 /** 541 * video_is_registered - returns true if the &struct video_device is registered. 542 * 543 * 544 * @vdev: pointer to &struct video_device 545 */ 546 static inline int video_is_registered(struct video_device *vdev) 547 { 548 return test_bit(V4L2_FL_REGISTERED, &vdev->flags); 549 } 550 551 #endif /* _V4L2_DEV_H */ 552