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  * @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 */