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 #define VFL_TYPE_GRABBER        0
  25 #define VFL_TYPE_VBI            1
  26 #define VFL_TYPE_RADIO          2
  27 #define VFL_TYPE_SUBDEV         3
  28 #define VFL_TYPE_SDR            4
  29 #define VFL_TYPE_TOUCH          5
  30 #define VFL_TYPE_MAX            6
  31
  32 /* Is this a receiver, transmitter or mem-to-mem? */
  33 /* Ignored for VFL_TYPE_SUBDEV. */
  34 #define VFL_DIR_RX              0
  35 #define VFL_DIR_TX              1
  36 #define VFL_DIR_M2M             2
  37
  38 struct v4l2_ioctl_callbacks;
  39 struct video_device;
  40 struct v4l2_device;
  41 struct v4l2_ctrl_handler;
  42
  43 /* Flag to mark the video_device struct as registered.
  44    Drivers can clear this flag if they want to block all future
  45    device access. It is cleared by video_unregister_device. */
  46 #define V4L2_FL_REGISTERED      (0)
  47 /* file->private_data points to struct v4l2_fh */
  48 #define V4L2_FL_USES_V4L2_FH    (1)
  49
  50 /* Priority helper functions */
  51
  52 /**
  53  * struct v4l2_prio_state - stores the priority states
  54  *
  55  * @prios: array with elements to store the array priorities
  56  *
  57  *
  58  * .. note::
  59  *    The size of @prios array matches the number of priority types defined
  60  *    by enum &v4l2_priority.
  61  */
  62 struct v4l2_prio_state {
  63         atomic_t prios[4];
  64 };
  65
  66 /**
  67  * v4l2_prio_init - initializes a struct v4l2_prio_state
  68  *
  69  * @global: pointer to &struct v4l2_prio_state
  70  */
  71 void v4l2_prio_init(struct v4l2_prio_state *global);
  72
  73 /**
  74  * v4l2_prio_change - changes the v4l2 file handler priority
  75  *
  76  * @global: pointer to the &struct v4l2_prio_state of the device node.
  77  * @local: pointer to the desired priority, as defined by enum &v4l2_priority
  78  * @new: Priority type requested, as defined by enum &v4l2_priority.
  79  *
  80  * .. note::
  81  *      This function should be used only by the V4L2 core.
  82  */
  83 int v4l2_prio_change(struct v4l2_prio_state *global, enum v4l2_priority *local,
  84                      enum v4l2_priority new);
  85
  86 /**
  87  * v4l2_prio_open - Implements the priority logic for a file handler open
  88  *
  89  * @global: pointer to the &struct v4l2_prio_state of the device node.
  90  * @local: pointer to the desired priority, as defined by enum &v4l2_priority
  91  *
  92  * .. note::
  93  *      This function should be used only by the V4L2 core.
  94  */
  95 void v4l2_prio_open(struct v4l2_prio_state *global, enum v4l2_priority *local);
  96
  97 /**
  98  * v4l2_prio_close - Implements the priority logic for a file handler close
  99  *
 100  * @global: pointer to the &struct v4l2_prio_state of the device node.
 101  * @local: priority to be released, as defined by enum &v4l2_priority
 102  *
 103  * .. note::
 104  *      This function should be used only by the V4L2 core.
 105  */
 106 void v4l2_prio_close(struct v4l2_prio_state *global, enum v4l2_priority local);
 107
 108 /**
 109  * v4l2_prio_max - Return the maximum priority, as stored at the @global array.
 110  *
 111  * @global: pointer to the &struct v4l2_prio_state of the device node.
 112  *
 113  * .. note::
 114  *      This function should be used only by the V4L2 core.
 115  */
 116 enum v4l2_priority v4l2_prio_max(struct v4l2_prio_state *global);
 117
 118 /**
 119  * v4l2_prio_check - Implements the priority logic for a file handler close
 120  *
 121  * @global: pointer to the &struct v4l2_prio_state of the device node.
 122  * @local: desired priority, as defined by enum &v4l2_priority local
 123  *
 124  * .. note::
 125  *      This function should be used only by the V4L2 core.
 126  */
 127 int v4l2_prio_check(struct v4l2_prio_state *global, enum v4l2_priority local);
 128
 129 /**
 130  * struct v4l2_file_operations - fs operations used by a V4L2 device
 131  *
 132  * @owner: pointer to struct module
 133  * @read: operations needed to implement the read() syscall
 134  * @write: operations needed to implement the write() syscall
 135  * @poll: operations needed to implement the poll() syscall
 136  * @unlocked_ioctl: operations needed to implement the ioctl() syscall
 137  * @compat_ioctl32: operations needed to implement the ioctl() syscall for
 138  *      the special case where the Kernel uses 64 bits instructions, but
 139  *      the userspace uses 32 bits.
 140  * @get_unmapped_area: called by the mmap() syscall, used when %!CONFIG_MMU
 141  * @mmap: operations needed to implement the mmap() syscall
 142  * @open: operations needed to implement the open() syscall
 143  * @release: operations needed to implement the release() syscall
 144  *
 145  * .. note::
 146  *
 147  *      Those operations are used to implemente the fs struct file_operations
 148  *      at the V4L2 drivers. The V4L2 core overrides the fs ops with some
 149  *      extra logic needed by the subsystem.
 150  */
 151 struct v4l2_file_operations {
 152         struct module *owner;
 153         ssize_t (*read) (struct file *, char __user *, size_t, loff_t *);
 154         ssize_t (*write) (struct file *, const char __user *, size_t, loff_t *);
 155         unsigned int (*poll) (struct file *, struct poll_table_struct *);
 156         long (*unlocked_ioctl) (struct file *, unsigned int, unsigned long);
 157 #ifdef CONFIG_COMPAT
 158         long (*compat_ioctl32) (struct file *, unsigned int, unsigned long);
 159 #endif
 160         unsigned long (*get_unmapped_area) (struct file *, unsigned long,
 161                                 unsigned long, unsigned long, unsigned long);
 162         int (*mmap) (struct file *, struct vm_area_struct *);
 163         int (*open) (struct file *);
 164         int (*release) (struct file *);
 165 };
 166
 167 /*
 168  * Newer version of video_device, handled by videodev2.c
 169  *      This version moves redundant code from video device code to
 170  *      the common handler
 171  */
 172
 173 /**
 174  * struct video_device - Structure used to create and manage the V4L2 device
 175  *      nodes.
 176  *
 177  * @entity: &struct media_entity
 178  * @intf_devnode: pointer to &struct media_intf_devnode
 179  * @pipe: &struct media_pipeline
 180  * @fops: pointer to &struct v4l2_file_operations for the video device
 181  * @device_caps: device capabilities as used in v4l2_capabilities
 182  * @dev: &struct device for the video device
 183  * @cdev: character device
 184  * @v4l2_dev: pointer to &struct v4l2_device parent
 185  * @dev_parent: pointer to &struct device parent
 186  * @ctrl_handler: Control handler associated with this device node.
 187  *       May be NULL.
 188  * @queue: &struct vb2_queue associated with this device node. May be NULL.
 189  * @prio: pointer to &struct v4l2_prio_state with device's Priority state.
 190  *       If NULL, then v4l2_dev->prio will be used.
 191  * @name: video device name
 192  * @vfl_type: V4L device type
 193  * @vfl_dir: V4L receiver, transmitter or m2m
 194  * @minor: device node 'minor'. It is set to -1 if the registration failed
 195  * @num: number of the video device node
 196  * @flags: video device flags. Use bitops to set/clear/test flags
 197  * @index: attribute to differentiate multiple indices on one physical device
 198  * @fh_lock: Lock for all v4l2_fhs
 199  * @fh_list: List of &struct v4l2_fh
 200  * @dev_debug: Internal device debug flags, not for use by drivers
 201  * @tvnorms: Supported tv norms
 202  *
 203  * @release: video device release() callback
 204  * @ioctl_ops: pointer to &struct v4l2_ioctl_ops with ioctl callbacks
 205  *
 206  * @valid_ioctls: bitmap with the valid ioctls for this device
 207  * @disable_locking: bitmap with the ioctls that don't require locking
 208  * @lock: pointer to &struct mutex serialization lock
 209  *
 210  * .. note::
 211  *      Only set @dev_parent if that can't be deduced from @v4l2_dev.
 212  */
 213
 214 struct video_device
 215 {
 216 #if defined(CONFIG_MEDIA_CONTROLLER)
 217         struct media_entity entity;
 218         struct media_intf_devnode *intf_devnode;
 219         struct media_pipeline pipe;
 220 #endif
 221         const struct v4l2_file_operations *fops;
 222
 223         u32 device_caps;
 224
 225         /* sysfs */
 226         struct device dev;
 227         struct cdev *cdev;
 228
 229         struct v4l2_device *v4l2_dev;
 230         struct device *dev_parent;
 231
 232         struct v4l2_ctrl_handler *ctrl_handler;
 233
 234         struct vb2_queue *queue;
 235
 236         struct v4l2_prio_state *prio;
 237
 238         /* device info */
 239         char name[32];
 240         int vfl_type;
 241         int vfl_dir;
 242         int minor;
 243         u16 num;
 244         unsigned long flags;
 245         int index;
 246
 247         /* V4L2 file handles */
 248         spinlock_t              fh_lock;
 249         struct list_head        fh_list;
 250
 251         int dev_debug;
 252
 253         v4l2_std_id tvnorms;
 254
 255         /* callbacks */
 256         void (*release)(struct video_device *vdev);
 257         const struct v4l2_ioctl_ops *ioctl_ops;
 258         DECLARE_BITMAP(valid_ioctls, BASE_VIDIOC_PRIVATE);
 259
 260         DECLARE_BITMAP(disable_locking, BASE_VIDIOC_PRIVATE);
 261         struct mutex *lock;
 262 };
 263
 264 #define media_entity_to_video_device(__e) \
 265         container_of(__e, struct video_device, entity)
 266 /* dev to video-device */
 267 #define to_video_device(cd) container_of(cd, struct video_device, dev)
 268
 269 /**
 270  * __video_register_device - register video4linux devices
 271  *
 272  * @vdev: struct video_device to register
 273  * @type: type of device to register
 274  * @nr:   which device node number is desired:
 275  *      (0 == /dev/video0, 1 == /dev/video1, ..., -1 == first free)
 276  * @warn_if_nr_in_use: warn if the desired device node number
 277  *        was already in use and another number was chosen instead.
 278  * @owner: module that owns the video device node
 279  *
 280  * The registration code assigns minor numbers and device node numbers
 281  * based on the requested type and registers the new device node with
 282  * the kernel.
 283  *
 284  * This function assumes that struct video_device was zeroed when it
 285  * was allocated and does not contain any stale date.
 286  *
 287  * An error is returned if no free minor or device node number could be
 288  * found, or if the registration of the device node failed.
 289  *
 290  * Returns 0 on success.
 291  *
 292  * Valid values for @type are:
 293  *
 294  *      - %VFL_TYPE_GRABBER - A frame grabber
 295  *      - %VFL_TYPE_VBI - Vertical blank data (undecoded)
 296  *      - %VFL_TYPE_RADIO - A radio card
 297  *      - %VFL_TYPE_SUBDEV - A subdevice
 298  *      - %VFL_TYPE_SDR - Software Defined Radio
 299  *      - %VFL_TYPE_TOUCH - A touch sensor
 300  *
 301  * .. note::
 302  *
 303  *      This function is meant to be used only inside the V4L2 core.
 304  *      Drivers should use video_register_device() or
 305  *      video_register_device_no_warn().
 306  */
 307 int __must_check __video_register_device(struct video_device *vdev, int type,
 308                 int nr, int warn_if_nr_in_use, struct module *owner);
 309
 310 /**
 311  *  video_register_device - register video4linux devices
 312  *
 313  * @vdev: struct video_device to register
 314  * @type: type of device to register
 315  * @nr:   which device node number is desired:
 316  *      (0 == /dev/video0, 1 == /dev/video1, ..., -1 == first free)
 317  *
 318  * Internally, it calls __video_register_device(). Please see its
 319  * documentation for more details.
 320  *
 321  * .. note::
 322  *      if video_register_device fails, the release() callback of
 323  *      &struct video_device structure is *not* called, so the caller
 324  *      is responsible for freeing any data. Usually that means that
 325  *      you video_device_release() should be called on failure.
 326  */
 327 static inline int __must_check video_register_device(struct video_device *vdev,
 328                 int type, int nr)
 329 {
 330         return __video_register_device(vdev, type, nr, 1, vdev->fops->owner);
 331 }
 332
 333 /**
 334  *  video_register_device_no_warn - register video4linux devices
 335  *
 336  * @vdev: struct video_device to register
 337  * @type: type of device to register
 338  * @nr:   which device node number is desired:
 339  *      (0 == /dev/video0, 1 == /dev/video1, ..., -1 == first free)
 340  *
 341  * This function is identical to video_register_device() except that no
 342  * warning is issued if the desired device node number was already in use.
 343  *
 344  * Internally, it calls __video_register_device(). Please see its
 345  * documentation for more details.
 346  *
 347  * .. note::
 348  *      if video_register_device fails, the release() callback of
 349  *      &struct video_device structure is *not* called, so the caller
 350  *      is responsible for freeing any data. Usually that means that
 351  *      you video_device_release() should be called on failure.
 352  */
 353 static inline int __must_check video_register_device_no_warn(
 354                 struct video_device *vdev, int type, int nr)
 355 {
 356         return __video_register_device(vdev, type, nr, 0, vdev->fops->owner);
 357 }
 358
 359 /**
 360  * video_unregister_device - Unregister video devices.
 361  *
 362  * @vdev: &struct video_device to register
 363  *
 364  * Does nothing if vdev == NULL or if video_is_registered() returns false.
 365  */
 366 void video_unregister_device(struct video_device *vdev);
 367
 368 /**
 369  * video_device_alloc - helper function to alloc &struct video_device
 370  *
 371  * Returns NULL if %-ENOMEM or a &struct video_device on success.
 372  */
 373 struct video_device * __must_check video_device_alloc(void);
 374
 375 /**
 376  * video_device_release - helper function to release &struct video_device
 377  *
 378  * @vdev: pointer to &struct video_device
 379  *
 380  * Can also be used for video_device->release\(\).
 381  */
 382 void video_device_release(struct video_device *vdev);
 383
 384 /**
 385  * video_device_release_empty - helper function to implement the
 386  *      video_device->release\(\) callback.
 387  *
 388  * @vdev: pointer to &struct video_device
 389  *
 390  * This release function does nothing.
 391  *
 392  * It should be used when the video_device is a static global struct.
 393  *
 394  * .. note::
 395  *      Having a static video_device is a dubious construction at best.
 396  */
 397 void video_device_release_empty(struct video_device *vdev);
 398
 399 /**
 400  * v4l2_is_known_ioctl - Checks if a given cmd is a known V4L ioctl
 401  *
 402  * @cmd: ioctl command
 403  *
 404  * returns true if cmd is a known V4L2 ioctl
 405  */
 406 bool v4l2_is_known_ioctl(unsigned int cmd);
 407
 408 /** v4l2_disable_ioctl_locking - mark that a given command
 409  *      shouldn't use core locking
 410  *
 411  * @vdev: pointer to &struct video_device
 412  * @cmd: ioctl command
 413  */
 414 static inline void v4l2_disable_ioctl_locking(struct video_device *vdev,
 415                                               unsigned int cmd)
 416 {
 417         if (_IOC_NR(cmd) < BASE_VIDIOC_PRIVATE)
 418                 set_bit(_IOC_NR(cmd), vdev->disable_locking);
 419 }
 420
 421 /**
 422  * v4l2_disable_ioctl- mark that a given command isn't implemented.
 423  *      shouldn't use core locking
 424  *
 425  * @vdev: pointer to &struct video_device
 426  * @cmd: ioctl command
 427  *
 428  * This function allows drivers to provide just one v4l2_ioctl_ops struct, but
 429  * disable ioctls based on the specific card that is actually found.
 430  *
 431  * .. note::
 432  *
 433  *    This must be called before video_register_device.
 434  *    See also the comments for determine_valid_ioctls().
 435  */
 436 static inline void v4l2_disable_ioctl(struct video_device *vdev,
 437                                       unsigned int cmd)
 438 {
 439         if (_IOC_NR(cmd) < BASE_VIDIOC_PRIVATE)
 440                 set_bit(_IOC_NR(cmd), vdev->valid_ioctls);
 441 }
 442
 443 /**
 444  * video_get_drvdata - gets private data from &struct video_device.
 445  *
 446  * @vdev: pointer to &struct video_device
 447  *
 448  * returns a pointer to the private data
 449  */
 450 static inline void *video_get_drvdata(struct video_device *vdev)
 451 {
 452         return dev_get_drvdata(&vdev->dev);
 453 }
 454
 455 /**
 456  * video_set_drvdata - sets private data from &struct video_device.
 457  *
 458  * @vdev: pointer to &struct video_device
 459  * @data: private data pointer
 460  */
 461 static inline void video_set_drvdata(struct video_device *vdev, void *data)
 462 {
 463         dev_set_drvdata(&vdev->dev, data);
 464 }
 465
 466 /**
 467  * video_devdata - gets &struct video_device from struct file.
 468  *
 469  * @file: pointer to struct file
 470  */
 471 struct video_device *video_devdata(struct file *file);
 472
 473 /**
 474  * video_drvdata - gets private data from &struct video_device using the
 475  *      struct file.
 476  *
 477  * @file: pointer to struct file
 478  *
 479  * This is function combines both video_get_drvdata() and video_devdata()
 480  * as this is used very often.
 481  */
 482 static inline void *video_drvdata(struct file *file)
 483 {
 484         return video_get_drvdata(video_devdata(file));
 485 }
 486
 487 /**
 488  * video_device_node_name - returns the video device name
 489  *
 490  * @vdev: pointer to &struct video_device
 491  *
 492  * Returns the device name string
 493  */
 494 static inline const char *video_device_node_name(struct video_device *vdev)
 495 {
 496         return dev_name(&vdev->dev);
 497 }
 498
 499 /**
 500  * video_is_registered - returns true if the &struct video_device is registered.
 501  *
 502  *
 503  * @vdev: pointer to &struct video_device
 504  */
 505 static inline int video_is_registered(struct video_device *vdev)
 506 {
 507         return test_bit(V4L2_FL_REGISTERED, &vdev->flags);
 508 }
 509
 510 #endif /* _V4L2_DEV_H */