include/media/v4l2-dev.h

   1 /*
   2  *
   3  *      V 4 L 2   D R I V E R   H E L P E R   A P I
   4  *
   5  * Moved from videodev2.h
   6  *
   7  *      Some commonly needed functions for drivers (v4l2-common.o module)
   8  */
   9 #ifndef _V4L2_DEV_H
  10 #define _V4L2_DEV_H
  11
  12 #include <linux/poll.h>
  13 #include <linux/fs.h>
  14 #include <linux/device.h>
  15 #include <linux/cdev.h>
  16 #include <linux/mutex.h>
  17 #include <linux/videodev2.h>
  18
  19 #include <media/media-entity.h>
  20
  21 #define VIDEO_MAJOR     81
  22
  23 #define VFL_TYPE_GRABBER        0
  24 #define VFL_TYPE_VBI            1
  25 #define VFL_TYPE_RADIO          2
  26 #define VFL_TYPE_SUBDEV         3
  27 #define VFL_TYPE_SDR            4
  28 #define VFL_TYPE_TOUCH          5
  29 #define VFL_TYPE_MAX            6
  30
  31 /* Is this a receiver, transmitter or mem-to-mem? */
  32 /* Ignored for VFL_TYPE_SUBDEV. */
  33 #define VFL_DIR_RX              0
  34 #define VFL_DIR_TX              1
  35 #define VFL_DIR_M2M             2
  36
  37 struct v4l2_ioctl_callbacks;
  38 struct video_device;
  39 struct v4l2_device;
  40 struct v4l2_ctrl_handler;
  41
  42 /* Flag to mark the video_device struct as registered.
  43    Drivers can clear this flag if they want to block all future
  44    device access. It is cleared by video_unregister_device. */
  45 #define V4L2_FL_REGISTERED      (0)
  46 /* file->private_data points to struct v4l2_fh */
  47 #define V4L2_FL_USES_V4L2_FH    (1)
  48
  49 /* Priority helper functions */
  50
  51 /**
  52  * struct v4l2_prio_state - stores the priority states
  53  *
  54  * @prios: array with elements to store the array priorities
  55  *
  56  *
  57  * .. note::
  58  *    The size of @prios array matches the number of priority types defined
  59  *    by enum &v4l2_priority.
  60  */
  61 struct v4l2_prio_state {
  62         atomic_t prios[4];
  63 };
  64
  65 /**
  66  * v4l2_prio_init - initializes a struct v4l2_prio_state
  67  *
  68  * @global: pointer to &struct v4l2_prio_state
  69  */
  70 void v4l2_prio_init(struct v4l2_prio_state *global);
  71
  72 /**
  73  * v4l2_prio_change - changes the v4l2 file handler priority
  74  *
  75  * @global: pointer to the &struct v4l2_prio_state of the device node.
  76  * @local: pointer to the desired priority, as defined by enum &v4l2_priority
  77  * @new: Priority type requested, as defined by enum &v4l2_priority.
  78  *
  79  * .. note::
  80  *      This function should be used only by the V4L2 core.
  81  */
  82 int v4l2_prio_change(struct v4l2_prio_state *global, enum v4l2_priority *local,
  83                      enum v4l2_priority new);
  84
  85 /**
  86  * v4l2_prio_open - Implements the priority logic for a file handler open
  87  *
  88  * @global: pointer to the &struct v4l2_prio_state of the device node.
  89  * @local: pointer to the desired priority, as defined by enum &v4l2_priority
  90  *
  91  * .. note::
  92  *      This function should be used only by the V4L2 core.
  93  */
  94 void v4l2_prio_open(struct v4l2_prio_state *global, enum v4l2_priority *local);
  95
  96 /**
  97  * v4l2_prio_close - Implements the priority logic for a file handler close
  98  *
  99  * @global: pointer to the &struct v4l2_prio_state of the device node.
 100  * @local: priority to be released, as defined by enum &v4l2_priority
 101  *
 102  * .. note::
 103  *      This function should be used only by the V4L2 core.
 104  */
 105 void v4l2_prio_close(struct v4l2_prio_state *global, enum v4l2_priority local);
 106
 107 /**
 108  * v4l2_prio_max - Return the maximum priority, as stored at the @global array.
 109  *
 110  * @global: pointer to the &struct v4l2_prio_state of the device node.
 111  *
 112  * .. note::
 113  *      This function should be used only by the V4L2 core.
 114  */
 115 enum v4l2_priority v4l2_prio_max(struct v4l2_prio_state *global);
 116
 117 /**
 118  * v4l2_prio_check - Implements the priority logic for a file handler close
 119  *
 120  * @global: pointer to the &struct v4l2_prio_state of the device node.
 121  * @local: desired priority, as defined by enum &v4l2_priority local
 122  *
 123  * .. note::
 124  *      This function should be used only by the V4L2 core.
 125  */
 126 int v4l2_prio_check(struct v4l2_prio_state *global, enum v4l2_priority local);
 127
 128 /**
 129  * struct v4l2_file_operations - fs operations used by a V4L2 device
 130  *
 131  * @owner: pointer to struct module
 132  * @read: operations needed to implement the read() syscall
 133  * @write: operations needed to implement the write() syscall
 134  * @poll: operations needed to implement the poll() syscall
 135  * @unlocked_ioctl: operations needed to implement the ioctl() syscall
 136  * @compat_ioctl32: operations needed to implement the ioctl() syscall for
 137  *      the special case where the Kernel uses 64 bits instructions, but
 138  *      the userspace uses 32 bits.
 139  * @get_unmapped_area: called by the mmap() syscall, used when %!CONFIG_MMU
 140  * @mmap: operations needed to implement the mmap() syscall
 141  * @open: operations needed to implement the open() syscall
 142  * @release: operations needed to implement the release() syscall
 143  *
 144  * .. note::
 145  *
 146  *      Those operations are used to implemente the fs struct file_operations
 147  *      at the V4L2 drivers. The V4L2 core overrides the fs ops with some
 148  *      extra logic needed by the subsystem.
 149  */
 150 struct v4l2_file_operations {
 151         struct module *owner;
 152         ssize_t (*read) (struct file *, char __user *, size_t, loff_t *);
 153         ssize_t (*write) (struct file *, const char __user *, size_t, loff_t *);
 154         unsigned int (*poll) (struct file *, struct poll_table_struct *);
 155         long (*unlocked_ioctl) (struct file *, unsigned int, unsigned long);
 156 #ifdef CONFIG_COMPAT
 157         long (*compat_ioctl32) (struct file *, unsigned int, unsigned long);
 158 #endif
 159         unsigned long (*get_unmapped_area) (struct file *, unsigned long,
 160                                 unsigned long, unsigned long, unsigned long);
 161         int (*mmap) (struct file *, struct vm_area_struct *);
 162         int (*open) (struct file *);
 163         int (*release) (struct file *);
 164 };
 165
 166 /*
 167  * Newer version of video_device, handled by videodev2.c
 168  *      This version moves redundant code from video device code to
 169  *      the common handler
 170  */
 171
 172 /**
 173  * struct video_device - Structure used to create and manage the V4L2 device
 174  *      nodes.
 175  *
 176  * @entity: &struct media_entity
 177  * @intf_devnode: pointer to &struct media_intf_devnode
 178  * @pipe: &struct media_pipeline
 179  * @fops: pointer to &struct v4l2_file_operations for the video device
 180  * @device_caps: device capabilities as used in v4l2_capabilities
 181  * @dev: &struct device for the video device
 182  * @cdev: character device
 183  * @v4l2_dev: pointer to &struct v4l2_device parent
 184  * @dev_parent: pointer to &struct device parent
 185  * @ctrl_handler: Control handler associated with this device node.
 186  *       May be NULL.
 187  * @queue: &struct vb2_queue associated with this device node. May be NULL.
 188  * @prio: pointer to &struct v4l2_prio_state with device's Priority state.
 189  *       If NULL, then v4l2_dev->prio will be used.
 190  * @name: video device name
 191  * @vfl_type: V4L device type
 192  * @vfl_dir: V4L receiver, transmitter or m2m
 193  * @minor: device node 'minor'. It is set to -1 if the registration failed
 194  * @num: number of the video device node
 195  * @flags: video device flags. Use bitops to set/clear/test flags
 196  * @index: attribute to differentiate multiple indices on one physical device
 197  * @fh_lock: Lock for all v4l2_fhs
 198  * @fh_list: List of &struct v4l2_fh
 199  * @dev_debug: Internal device debug flags, not for use by drivers
 200  * @tvnorms: Supported tv norms
 201  *
 202  * @release: video device release() callback
 203  * @ioctl_ops: pointer to &struct v4l2_ioctl_ops with ioctl callbacks
 204  *
 205  * @valid_ioctls: bitmap with the valid ioctls for this device
 206  * @disable_locking: bitmap with the ioctls that don't require locking
 207  * @lock: pointer to &struct mutex serialization lock
 208  *
 209  * .. note::
 210  *      Only set @dev_parent if that can't be deduced from @v4l2_dev.
 211  */
 212
 213 struct video_device
 214 {
 215 #if defined(CONFIG_MEDIA_CONTROLLER)
 216         struct media_entity entity;
 217         struct media_intf_devnode *intf_devnode;
 218         struct media_pipeline pipe;
 219 #endif
 220         const struct v4l2_file_operations *fops;
 221
 222         u32 device_caps;
 223
 224         /* sysfs */
 225         struct device dev;
 226         struct cdev *cdev;
 227
 228         struct v4l2_device *v4l2_dev;
 229         struct device *dev_parent;
 230
 231         struct v4l2_ctrl_handler *ctrl_handler;
 232
 233         struct vb2_queue *queue;
 234
 235         struct v4l2_prio_state *prio;
 236
 237         /* device info */
 238         char name[32];
 239         int vfl_type;
 240         int vfl_dir;
 241         int minor;
 242         u16 num;
 243         unsigned long flags;
 244         int index;
 245
 246         /* V4L2 file handles */
 247         spinlock_t              fh_lock;
 248         struct list_head        fh_list;
 249
 250         int dev_debug;
 251
 252         v4l2_std_id tvnorms;
 253
 254         /* callbacks */
 255         void (*release)(struct video_device *vdev);
 256         const struct v4l2_ioctl_ops *ioctl_ops;
 257         DECLARE_BITMAP(valid_ioctls, BASE_VIDIOC_PRIVATE);
 258
 259         DECLARE_BITMAP(disable_locking, BASE_VIDIOC_PRIVATE);
 260         struct mutex *lock;
 261 };
 262
 263 #define media_entity_to_video_device(__e) \
 264         container_of(__e, struct video_device, entity)
 265 /* dev to video-device */
 266 #define to_video_device(cd) container_of(cd, struct video_device, dev)
 267
 268 /**
 269  * __video_register_device - register video4linux devices
 270  *
 271  * @vdev: struct video_device to register
 272  * @type: type of device to register
 273  * @nr:   which device node number is desired:
 274  *      (0 == /dev/video0, 1 == /dev/video1, ..., -1 == first free)
 275  * @warn_if_nr_in_use: warn if the desired device node number
 276  *        was already in use and another number was chosen instead.
 277  * @owner: module that owns the video device node
 278  *
 279  * The registration code assigns minor numbers and device node numbers
 280  * based on the requested type and registers the new device node with
 281  * the kernel.
 282  *
 283  * This function assumes that struct video_device was zeroed when it
 284  * was allocated and does not contain any stale date.
 285  *
 286  * An error is returned if no free minor or device node number could be
 287  * found, or if the registration of the device node failed.
 288  *
 289  * Returns 0 on success.
 290  *
 291  * Valid values for @type are:
 292  *
 293  *      - %VFL_TYPE_GRABBER - A frame grabber
 294  *      - %VFL_TYPE_VBI - Vertical blank data (undecoded)
 295  *      - %VFL_TYPE_RADIO - A radio card
 296  *      - %VFL_TYPE_SUBDEV - A subdevice
 297  *      - %VFL_TYPE_SDR - Software Defined Radio
 298  *      - %VFL_TYPE_TOUCH - A touch sensor
 299  *
 300  * .. note::
 301  *
 302  *      This function is meant to be used only inside the V4L2 core.
 303  *      Drivers should use video_register_device() or
 304  *      video_register_device_no_warn().
 305  */
 306 int __must_check __video_register_device(struct video_device *vdev, int type,
 307                 int nr, int warn_if_nr_in_use, struct module *owner);
 308
 309 /**
 310  *  video_register_device - register video4linux devices
 311  *
 312  * @vdev: struct video_device to register
 313  * @type: type of device to register
 314  * @nr:   which device node number is desired:
 315  *      (0 == /dev/video0, 1 == /dev/video1, ..., -1 == first free)
 316  *
 317  * Internally, it calls __video_register_device(). Please see its
 318  * documentation for more details.
 319  *
 320  * .. note::
 321  *      if video_register_device fails, the release() callback of
 322  *      &struct video_device structure is *not* called, so the caller
 323  *      is responsible for freeing any data. Usually that means that
 324  *      you video_device_release() should be called on failure.
 325  */
 326 static inline int __must_check video_register_device(struct video_device *vdev,
 327                 int type, int nr)
 328 {
 329         return __video_register_device(vdev, type, nr, 1, vdev->fops->owner);
 330 }
 331
 332 /**
 333  *  video_register_device_no_warn - register video4linux devices
 334  *
 335  * @vdev: struct video_device to register
 336  * @type: type of device to register
 337  * @nr:   which device node number is desired:
 338  *      (0 == /dev/video0, 1 == /dev/video1, ..., -1 == first free)
 339  *
 340  * This function is identical to video_register_device() except that no
 341  * warning is issued if the desired device node number was already in use.
 342  *
 343  * Internally, it calls __video_register_device(). Please see its
 344  * documentation for more details.
 345  *
 346  * .. note::
 347  *      if video_register_device fails, the release() callback of
 348  *      &struct video_device structure is *not* called, so the caller
 349  *      is responsible for freeing any data. Usually that means that
 350  *      you video_device_release() should be called on failure.
 351  */
 352 static inline int __must_check video_register_device_no_warn(
 353                 struct video_device *vdev, int type, int nr)
 354 {
 355         return __video_register_device(vdev, type, nr, 0, vdev->fops->owner);
 356 }
 357
 358 /**
 359  * video_unregister_device - Unregister video devices.
 360  *
 361  * @vdev: &struct video_device to register
 362  *
 363  * Does nothing if vdev == NULL or if video_is_registered() returns false.
 364  */
 365 void video_unregister_device(struct video_device *vdev);
 366
 367 /**
 368  * video_device_alloc - helper function to alloc &struct video_device
 369  *
 370  * Returns NULL if %-ENOMEM or a &struct video_device on success.
 371  */
 372 struct video_device * __must_check video_device_alloc(void);
 373
 374 /**
 375  * video_device_release - helper function to release &struct video_device
 376  *
 377  * @vdev: pointer to &struct video_device
 378  *
 379  * Can also be used for video_device->release\(\).
 380  */
 381 void video_device_release(struct video_device *vdev);
 382
 383 /**
 384  * video_device_release_empty - helper function to implement the
 385  *      video_device->release\(\) callback.
 386  *
 387  * @vdev: pointer to &struct video_device
 388  *
 389  * This release function does nothing.
 390  *
 391  * It should be used when the video_device is a static global struct.
 392  *
 393  * .. note::
 394  *      Having a static video_device is a dubious construction at best.
 395  */
 396 void video_device_release_empty(struct video_device *vdev);
 397
 398 /**
 399  * v4l2_is_known_ioctl - Checks if a given cmd is a known V4L ioctl
 400  *
 401  * @cmd: ioctl command
 402  *
 403  * returns true if cmd is a known V4L2 ioctl
 404  */
 405 bool v4l2_is_known_ioctl(unsigned int cmd);
 406
 407 /** v4l2_disable_ioctl_locking - mark that a given command
 408  *      shouldn't use core locking
 409  *
 410  * @vdev: pointer to &struct video_device
 411  * @cmd: ioctl command
 412  */
 413 static inline void v4l2_disable_ioctl_locking(struct video_device *vdev,
 414                                               unsigned int cmd)
 415 {
 416         if (_IOC_NR(cmd) < BASE_VIDIOC_PRIVATE)
 417                 set_bit(_IOC_NR(cmd), vdev->disable_locking);
 418 }
 419
 420 /**
 421  * v4l2_disable_ioctl- mark that a given command isn't implemented.
 422  *      shouldn't use core locking
 423  *
 424  * @vdev: pointer to &struct video_device
 425  * @cmd: ioctl command
 426  *
 427  * This function allows drivers to provide just one v4l2_ioctl_ops struct, but
 428  * disable ioctls based on the specific card that is actually found.
 429  *
 430  * .. note::
 431  *
 432  *    This must be called before video_register_device.
 433  *    See also the comments for determine_valid_ioctls().
 434  */
 435 static inline void v4l2_disable_ioctl(struct video_device *vdev,
 436                                       unsigned int cmd)
 437 {
 438         if (_IOC_NR(cmd) < BASE_VIDIOC_PRIVATE)
 439                 set_bit(_IOC_NR(cmd), vdev->valid_ioctls);
 440 }
 441
 442 /**
 443  * video_get_drvdata - gets private data from &struct video_device.
 444  *
 445  * @vdev: pointer to &struct video_device
 446  *
 447  * returns a pointer to the private data
 448  */
 449 static inline void *video_get_drvdata(struct video_device *vdev)
 450 {
 451         return dev_get_drvdata(&vdev->dev);
 452 }
 453
 454 /**
 455  * video_set_drvdata - sets private data from &struct video_device.
 456  *
 457  * @vdev: pointer to &struct video_device
 458  * @data: private data pointer
 459  */
 460 static inline void video_set_drvdata(struct video_device *vdev, void *data)
 461 {
 462         dev_set_drvdata(&vdev->dev, data);
 463 }
 464
 465 /**
 466  * video_devdata - gets &struct video_device from struct file.
 467  *
 468  * @file: pointer to struct file
 469  */
 470 struct video_device *video_devdata(struct file *file);
 471
 472 /**
 473  * video_drvdata - gets private data from &struct video_device using the
 474  *      struct file.
 475  *
 476  * @file: pointer to struct file
 477  *
 478  * This is function combines both video_get_drvdata() and video_devdata()
 479  * as this is used very often.
 480  */
 481 static inline void *video_drvdata(struct file *file)
 482 {
 483         return video_get_drvdata(video_devdata(file));
 484 }
 485
 486 /**
 487  * video_device_node_name - returns the video device name
 488  *
 489  * @vdev: pointer to &struct video_device
 490  *
 491  * Returns the device name string
 492  */
 493 static inline const char *video_device_node_name(struct video_device *vdev)
 494 {
 495         return dev_name(&vdev->dev);
 496 }
 497
 498 /**
 499  * video_is_registered - returns true if the &struct video_device is registered.
 500  *
 501  *
 502  * @vdev: pointer to &struct video_device
 503  */
 504 static inline int video_is_registered(struct video_device *vdev)
 505 {
 506         return test_bit(V4L2_FL_REGISTERED, &vdev->flags);
 507 }
 508
 509 #endif /* _V4L2_DEV_H */