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_VIDEO:     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_VIDEO,
  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_devnode_direction - Identifies if a &struct video_device
  47  *      corresponds 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  * @V4L2_FL_QUIRK_INVERTED_CROP:
  78  *      some old M2M drivers use g/s_crop/cropcap incorrectly: crop and
  79  *      compose are swapped. If this flag is set, then the selection
  80  *      targets are swapped in the g/s_crop/cropcap functions in v4l2-ioctl.c.
  81  *      This allows those drivers to correctly implement the selection API,
  82  *      but the old crop API will still work as expected in order to preserve
  83  *      backwards compatibility.
  84  *      Never set this flag for new drivers.
  85  * @V4L2_FL_SUBDEV_RO_DEVNODE:
  86  *      indicates that the video device node is registered in read-only mode.
  87  *      The flag only applies to device nodes registered for sub-devices, it is
  88  *      set by the core when the sub-devices device nodes are registered with
  89  *      v4l2_device_register_ro_subdev_nodes() and used by the sub-device ioctl
  90  *      handler to restrict access to some ioctl calls.
  91  */
  92 enum v4l2_video_device_flags {
  93         V4L2_FL_REGISTERED              = 0,
  94         V4L2_FL_USES_V4L2_FH            = 1,
  95         V4L2_FL_QUIRK_INVERTED_CROP     = 2,
  96         V4L2_FL_SUBDEV_RO_DEVNODE       = 3,
  97 };
  98
  99 /* Priority helper functions */
 100
 101 /**
 102  * struct v4l2_prio_state - stores the priority states
 103  *
 104  * @prios: array with elements to store the array priorities
 105  *
 106  *
 107  * .. note::
 108  *    The size of @prios array matches the number of priority types defined
 109  *    by enum &v4l2_priority.
 110  */
 111 struct v4l2_prio_state {
 112         atomic_t prios[4];
 113 };
 114
 115 /**
 116  * v4l2_prio_init - initializes a struct v4l2_prio_state
 117  *
 118  * @global: pointer to &struct v4l2_prio_state
 119  */
 120 void v4l2_prio_init(struct v4l2_prio_state *global);
 121
 122 /**
 123  * v4l2_prio_change - changes the v4l2 file handler priority
 124  *
 125  * @global: pointer to the &struct v4l2_prio_state of the device node.
 126  * @local: pointer to the desired priority, as defined by enum &v4l2_priority
 127  * @new: Priority type requested, as defined by enum &v4l2_priority.
 128  *
 129  * .. note::
 130  *      This function should be used only by the V4L2 core.
 131  */
 132 int v4l2_prio_change(struct v4l2_prio_state *global, enum v4l2_priority *local,
 133                      enum v4l2_priority new);
 134
 135 /**
 136  * v4l2_prio_open - Implements the priority logic for a file handler open
 137  *
 138  * @global: pointer to the &struct v4l2_prio_state of the device node.
 139  * @local: pointer to the desired priority, as defined by enum &v4l2_priority
 140  *
 141  * .. note::
 142  *      This function should be used only by the V4L2 core.
 143  */
 144 void v4l2_prio_open(struct v4l2_prio_state *global, enum v4l2_priority *local);
 145
 146 /**
 147  * v4l2_prio_close - Implements the priority logic for a file handler close
 148  *
 149  * @global: pointer to the &struct v4l2_prio_state of the device node.
 150  * @local: priority to be released, as defined by enum &v4l2_priority
 151  *
 152  * .. note::
 153  *      This function should be used only by the V4L2 core.
 154  */
 155 void v4l2_prio_close(struct v4l2_prio_state *global, enum v4l2_priority local);
 156
 157 /**
 158  * v4l2_prio_max - Return the maximum priority, as stored at the @global array.
 159  *
 160  * @global: pointer to the &struct v4l2_prio_state of the device node.
 161  *
 162  * .. note::
 163  *      This function should be used only by the V4L2 core.
 164  */
 165 enum v4l2_priority v4l2_prio_max(struct v4l2_prio_state *global);
 166
 167 /**
 168  * v4l2_prio_check - Implements the priority logic for a file handler close
 169  *
 170  * @global: pointer to the &struct v4l2_prio_state of the device node.
 171  * @local: desired priority, as defined by enum &v4l2_priority local
 172  *
 173  * .. note::
 174  *      This function should be used only by the V4L2 core.
 175  */
 176 int v4l2_prio_check(struct v4l2_prio_state *global, enum v4l2_priority local);
 177
 178 /**
 179  * struct v4l2_file_operations - fs operations used by a V4L2 device
 180  *
 181  * @owner: pointer to struct module
 182  * @read: operations needed to implement the read() syscall
 183  * @write: operations needed to implement the write() syscall
 184  * @poll: operations needed to implement the poll() syscall
 185  * @unlocked_ioctl: operations needed to implement the ioctl() syscall
 186  * @compat_ioctl32: operations needed to implement the ioctl() syscall for
 187  *      the special case where the Kernel uses 64 bits instructions, but
 188  *      the userspace uses 32 bits.
 189  * @get_unmapped_area: called by the mmap() syscall, used when %!CONFIG_MMU
 190  * @mmap: operations needed to implement the mmap() syscall
 191  * @open: operations needed to implement the open() syscall
 192  * @release: operations needed to implement the release() syscall
 193  *
 194  * .. note::
 195  *
 196  *      Those operations are used to implemente the fs struct file_operations
 197  *      at the V4L2 drivers. The V4L2 core overrides the fs ops with some
 198  *      extra logic needed by the subsystem.
 199  */
 200 struct v4l2_file_operations {
 201         struct module *owner;
 202         ssize_t (*read) (struct file *, char __user *, size_t, loff_t *);
 203         ssize_t (*write) (struct file *, const char __user *, size_t, loff_t *);
 204         __poll_t (*poll) (struct file *, struct poll_table_struct *);
 205         long (*unlocked_ioctl) (struct file *, unsigned int, unsigned long);
 206 #ifdef CONFIG_COMPAT
 207         long (*compat_ioctl32) (struct file *, unsigned int, unsigned long);
 208 #endif
 209         unsigned long (*get_unmapped_area) (struct file *, unsigned long,
 210                                 unsigned long, unsigned long, unsigned long);
 211         int (*mmap) (struct file *, struct vm_area_struct *);
 212         int (*open) (struct file *);
 213         int (*release) (struct file *);
 214 };
 215
 216 /*
 217  * Newer version of video_device, handled by videodev2.c
 218  *      This version moves redundant code from video device code to
 219  *      the common handler
 220  */
 221
 222 /**
 223  * struct video_device - Structure used to create and manage the V4L2 device
 224  *      nodes.
 225  *
 226  * @entity: &struct media_entity
 227  * @intf_devnode: pointer to &struct media_intf_devnode
 228  * @pipe: &struct media_pipeline
 229  * @fops: pointer to &struct v4l2_file_operations for the video device
 230  * @device_caps: device capabilities as used in v4l2_capabilities
 231  * @dev: &struct device for the video device
 232  * @cdev: character device
 233  * @v4l2_dev: pointer to &struct v4l2_device parent
 234  * @dev_parent: pointer to &struct device parent
 235  * @ctrl_handler: Control handler associated with this device node.
 236  *       May be NULL.
 237  * @queue: &struct vb2_queue associated with this device node. May be NULL.
 238  * @prio: pointer to &struct v4l2_prio_state with device's Priority state.
 239  *       If NULL, then v4l2_dev->prio will be used.
 240  * @name: video device name
 241  * @vfl_type: V4L device type, as defined by &enum vfl_devnode_type
 242  * @vfl_dir: V4L receiver, transmitter or m2m
 243  * @minor: device node 'minor'. It is set to -1 if the registration failed
 244  * @num: number of the video device node
 245  * @flags: video device flags. Use bitops to set/clear/test flags.
 246  *         Contains a set of &enum v4l2_video_device_flags.
 247  * @index: attribute to differentiate multiple indices on one physical device
 248  * @fh_lock: Lock for all v4l2_fhs
 249  * @fh_list: List of &struct v4l2_fh
 250  * @dev_debug: Internal device debug flags, not for use by drivers
 251  * @tvnorms: Supported tv norms
 252  *
 253  * @release: video device release() callback
 254  * @ioctl_ops: pointer to &struct v4l2_ioctl_ops with ioctl callbacks
 255  *
 256  * @valid_ioctls: bitmap with the valid ioctls for this device
 257  * @lock: pointer to &struct mutex serialization lock
 258  *
 259  * .. note::
 260  *      Only set @dev_parent if that can't be deduced from @v4l2_dev.
 261  */
 262
 263 struct video_device
 264 {
 265 #if defined(CONFIG_MEDIA_CONTROLLER)
 266         struct media_entity entity;
 267         struct media_intf_devnode *intf_devnode;
 268         struct media_pipeline pipe;
 269 #endif
 270         const struct v4l2_file_operations *fops;
 271
 272         u32 device_caps;
 273
 274         /* sysfs */
 275         struct device dev;
 276         struct cdev *cdev;
 277
 278         struct v4l2_device *v4l2_dev;
 279         struct device *dev_parent;
 280
 281         struct v4l2_ctrl_handler *ctrl_handler;
 282
 283         struct vb2_queue *queue;
 284
 285         struct v4l2_prio_state *prio;
 286
 287         /* device info */
 288         char name[32];
 289         enum vfl_devnode_type vfl_type;
 290         enum vfl_devnode_direction vfl_dir;
 291         int minor;
 292         u16 num;
 293         unsigned long flags;
 294         int index;
 295
 296         /* V4L2 file handles */
 297         spinlock_t              fh_lock;
 298         struct list_head        fh_list;
 299
 300         int dev_debug;
 301
 302         v4l2_std_id tvnorms;
 303
 304         /* callbacks */
 305         void (*release)(struct video_device *vdev);
 306         const struct v4l2_ioctl_ops *ioctl_ops;
 307         DECLARE_BITMAP(valid_ioctls, BASE_VIDIOC_PRIVATE);
 308
 309         struct mutex *lock;
 310 };
 311
 312 /**
 313  * media_entity_to_video_device - Returns a &struct video_device from
 314  *      the &struct media_entity embedded on it.
 315  *
 316  * @__entity: pointer to &struct media_entity
 317  */
 318 #define media_entity_to_video_device(__entity) \
 319         container_of(__entity, struct video_device, entity)
 320
 321 /**
 322  * to_video_device - Returns a &struct video_device from the
 323  *      &struct device embedded on it.
 324  *
 325  * @cd: pointer to &struct device
 326  */
 327 #define to_video_device(cd) container_of(cd, struct video_device, dev)
 328
 329 /**
 330  * __video_register_device - register video4linux devices
 331  *
 332  * @vdev: struct video_device to register
 333  * @type: type of device to register, as defined by &enum vfl_devnode_type
 334  * @nr:   which device node number is desired:
 335  *      (0 == /dev/video0, 1 == /dev/video1, ..., -1 == first free)
 336  * @warn_if_nr_in_use: warn if the desired device node number
 337  *        was already in use and another number was chosen instead.
 338  * @owner: module that owns the video device node
 339  *
 340  * The registration code assigns minor numbers and device node numbers
 341  * based on the requested type and registers the new device node with
 342  * the kernel.
 343  *
 344  * This function assumes that struct video_device was zeroed when it
 345  * was allocated and does not contain any stale date.
 346  *
 347  * An error is returned if no free minor or device node number could be
 348  * found, or if the registration of the device node failed.
 349  *
 350  * Returns 0 on success.
 351  *
 352  * .. note::
 353  *
 354  *      This function is meant to be used only inside the V4L2 core.
 355  *      Drivers should use video_register_device() or
 356  *      video_register_device_no_warn().
 357  */
 358 int __must_check __video_register_device(struct video_device *vdev,
 359                                          enum vfl_devnode_type type,
 360                                          int nr, int warn_if_nr_in_use,
 361                                          struct module *owner);
 362
 363 /**
 364  *  video_register_device - register video4linux devices
 365  *
 366  * @vdev: struct video_device to register
 367  * @type: type of device to register, as defined by &enum vfl_devnode_type
 368  * @nr:   which device node number is desired:
 369  *      (0 == /dev/video0, 1 == /dev/video1, ..., -1 == first free)
 370  *
 371  * Internally, it calls __video_register_device(). Please see its
 372  * documentation for more details.
 373  *
 374  * .. note::
 375  *      if video_register_device fails, the release() callback of
 376  *      &struct video_device structure is *not* called, so the caller
 377  *      is responsible for freeing any data. Usually that means that
 378  *      you video_device_release() should be called on failure.
 379  */
 380 static inline int __must_check video_register_device(struct video_device *vdev,
 381                                                      enum vfl_devnode_type type,
 382                                                      int nr)
 383 {
 384         return __video_register_device(vdev, type, nr, 1, vdev->fops->owner);
 385 }
 386
 387 /**
 388  *  video_register_device_no_warn - register video4linux devices
 389  *
 390  * @vdev: struct video_device to register
 391  * @type: type of device to register, as defined by &enum vfl_devnode_type
 392  * @nr:   which device node number is desired:
 393  *      (0 == /dev/video0, 1 == /dev/video1, ..., -1 == first free)
 394  *
 395  * This function is identical to video_register_device() except that no
 396  * warning is issued if the desired device node number was already in use.
 397  *
 398  * Internally, it calls __video_register_device(). Please see its
 399  * documentation for more details.
 400  *
 401  * .. note::
 402  *      if video_register_device fails, the release() callback of
 403  *      &struct video_device structure is *not* called, so the caller
 404  *      is responsible for freeing any data. Usually that means that
 405  *      you video_device_release() should be called on failure.
 406  */
 407 static inline int __must_check
 408 video_register_device_no_warn(struct video_device *vdev,
 409                               enum vfl_devnode_type type, int nr)
 410 {
 411         return __video_register_device(vdev, type, nr, 0, vdev->fops->owner);
 412 }
 413
 414 /**
 415  * video_unregister_device - Unregister video devices.
 416  *
 417  * @vdev: &struct video_device to register
 418  *
 419  * Does nothing if vdev == NULL or if video_is_registered() returns false.
 420  */
 421 void video_unregister_device(struct video_device *vdev);
 422
 423 /**
 424  * video_device_alloc - helper function to alloc &struct video_device
 425  *
 426  * Returns NULL if %-ENOMEM or a &struct video_device on success.
 427  */
 428 struct video_device * __must_check video_device_alloc(void);
 429
 430 /**
 431  * video_device_release - helper function to release &struct video_device
 432  *
 433  * @vdev: pointer to &struct video_device
 434  *
 435  * Can also be used for video_device->release\(\).
 436  */
 437 void video_device_release(struct video_device *vdev);
 438
 439 /**
 440  * video_device_release_empty - helper function to implement the
 441  *      video_device->release\(\) callback.
 442  *
 443  * @vdev: pointer to &struct video_device
 444  *
 445  * This release function does nothing.
 446  *
 447  * It should be used when the video_device is a static global struct.
 448  *
 449  * .. note::
 450  *      Having a static video_device is a dubious construction at best.
 451  */
 452 void video_device_release_empty(struct video_device *vdev);
 453
 454 /**
 455  * v4l2_disable_ioctl- mark that a given command isn't implemented.
 456  *      shouldn't use core locking
 457  *
 458  * @vdev: pointer to &struct video_device
 459  * @cmd: ioctl command
 460  *
 461  * This function allows drivers to provide just one v4l2_ioctl_ops struct, but
 462  * disable ioctls based on the specific card that is actually found.
 463  *
 464  * .. note::
 465  *
 466  *    This must be called before video_register_device.
 467  *    See also the comments for determine_valid_ioctls().
 468  */
 469 static inline void v4l2_disable_ioctl(struct video_device *vdev,
 470                                       unsigned int cmd)
 471 {
 472         if (_IOC_NR(cmd) < BASE_VIDIOC_PRIVATE)
 473                 set_bit(_IOC_NR(cmd), vdev->valid_ioctls);
 474 }
 475
 476 /**
 477  * video_get_drvdata - gets private data from &struct video_device.
 478  *
 479  * @vdev: pointer to &struct video_device
 480  *
 481  * returns a pointer to the private data
 482  */
 483 static inline void *video_get_drvdata(struct video_device *vdev)
 484 {
 485         return dev_get_drvdata(&vdev->dev);
 486 }
 487
 488 /**
 489  * video_set_drvdata - sets private data from &struct video_device.
 490  *
 491  * @vdev: pointer to &struct video_device
 492  * @data: private data pointer
 493  */
 494 static inline void video_set_drvdata(struct video_device *vdev, void *data)
 495 {
 496         dev_set_drvdata(&vdev->dev, data);
 497 }
 498
 499 /**
 500  * video_devdata - gets &struct video_device from struct file.
 501  *
 502  * @file: pointer to struct file
 503  */
 504 struct video_device *video_devdata(struct file *file);
 505
 506 /**
 507  * video_drvdata - gets private data from &struct video_device using the
 508  *      struct file.
 509  *
 510  * @file: pointer to struct file
 511  *
 512  * This is function combines both video_get_drvdata() and video_devdata()
 513  * as this is used very often.
 514  */
 515 static inline void *video_drvdata(struct file *file)
 516 {
 517         return video_get_drvdata(video_devdata(file));
 518 }
 519
 520 /**
 521  * video_device_node_name - returns the video device name
 522  *
 523  * @vdev: pointer to &struct video_device
 524  *
 525  * Returns the device name string
 526  */
 527 static inline const char *video_device_node_name(struct video_device *vdev)
 528 {
 529         return dev_name(&vdev->dev);
 530 }
 531
 532 /**
 533  * video_is_registered - returns true if the &struct video_device is registered.
 534  *
 535  *
 536  * @vdev: pointer to &struct video_device
 537  */
 538 static inline int video_is_registered(struct video_device *vdev)
 539 {
 540         return test_bit(V4L2_FL_REGISTERED, &vdev->flags);
 541 }
 542
 543 #endif /* _V4L2_DEV_H */