include/media/v4l2-dev.h

   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 */