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