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Linux/include/media/v4l2-dev.h

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  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 */
528 

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