summaryrefslogtreecommitdiffstats
path: root/include/media/v4l2-dev.h
blob: 53f32022fabe5c5aa11b39790d9119f775fac758 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
/* SPDX-License-Identifier: GPL-2.0 */
/*
 *
 *	V 4 L 2   D R I V E R   H E L P E R   A P I
 *
 * Moved from videodev2.h
 *
 *	Some commonly needed functions for drivers (v4l2-common.o module)
 */
#ifndef _V4L2_DEV_H
#define _V4L2_DEV_H

#include <linux/poll.h>
#include <linux/fs.h>
#include <linux/device.h>
#include <linux/cdev.h>
#include <linux/mutex.h>
#include <linux/videodev2.h>

#include <media/media-entity.h>

#define VIDEO_MAJOR	81

/**
 * enum vfl_devnode_type - type of V4L2 device node
 *
 * @VFL_TYPE_GRABBER:	for video input/output devices
 * @VFL_TYPE_VBI:	for vertical blank data (i.e. closed captions, teletext)
 * @VFL_TYPE_RADIO:	for radio tuners
 * @VFL_TYPE_SUBDEV:	for V4L2 subdevices
 * @VFL_TYPE_SDR:	for Software Defined Radio tuners
 * @VFL_TYPE_TOUCH:	for touch sensors
 */
enum vfl_devnode_type {
	VFL_TYPE_GRABBER	= 0,
	VFL_TYPE_VBI		= 1,
	VFL_TYPE_RADIO		= 2,
	VFL_TYPE_SUBDEV		= 3,
	VFL_TYPE_SDR		= 4,
	VFL_TYPE_TOUCH		= 5,
};
#define VFL_TYPE_MAX VFL_TYPE_TOUCH

/**
 * enum  vfl_direction - Identifies if a &struct video_device corresponds
 *	to a receiver, a transmitter or a mem-to-mem device.
 *
 * @VFL_DIR_RX:		device is a receiver.
 * @VFL_DIR_TX:		device is a transmitter.
 * @VFL_DIR_M2M:	device is a memory to memory device.
 *
 * Note: Ignored if &enum vfl_devnode_type is %VFL_TYPE_SUBDEV.
 */
enum vfl_devnode_direction {
	VFL_DIR_RX,
	VFL_DIR_TX,
	VFL_DIR_M2M,
};

struct v4l2_ioctl_callbacks;
struct video_device;
struct v4l2_device;
struct v4l2_ctrl_handler;

/**
 * enum v4l2_video_device_flags - Flags used by &struct video_device
 *
 * @V4L2_FL_REGISTERED:
 *	indicates that a &struct video_device is registered.
 *	Drivers can clear this flag if they want to block all future
 *	device access. It is cleared by video_unregister_device.
 * @V4L2_FL_USES_V4L2_FH:
 *	indicates that file->private_data points to &struct v4l2_fh.
 *	This flag is set by the core when v4l2_fh_init() is called.
 *	All new drivers should use it.
 */
enum v4l2_video_device_flags {
	V4L2_FL_REGISTERED	= 0,
	V4L2_FL_USES_V4L2_FH	= 1,
};

/* Priority helper functions */

/**
 * struct v4l2_prio_state - stores the priority states
 *
 * @prios: array with elements to store the array priorities
 *
 *
 * .. note::
 *    The size of @prios array matches the number of priority types defined
 *    by enum &v4l2_priority.
 */
struct v4l2_prio_state {
	atomic_t prios[4];
};

/**
 * v4l2_prio_init - initializes a struct v4l2_prio_state
 *
 * @global: pointer to &struct v4l2_prio_state
 */
void v4l2_prio_init(struct v4l2_prio_state *global);

/**
 * v4l2_prio_change - changes the v4l2 file handler priority
 *
 * @global: pointer to the &struct v4l2_prio_state of the device node.
 * @local: pointer to the desired priority, as defined by enum &v4l2_priority
 * @new: Priority type requested, as defined by enum &v4l2_priority.
 *
 * .. note::
 *	This function should be used only by the V4L2 core.
 */
int v4l2_prio_change(struct v4l2_prio_state *global, enum v4l2_priority *local,
		     enum v4l2_priority new);

/**
 * v4l2_prio_open - Implements the priority logic for a file handler open
 *
 * @global: pointer to the &struct v4l2_prio_state of the device node.
 * @local: pointer to the desired priority, as defined by enum &v4l2_priority
 *
 * .. note::
 *	This function should be used only by the V4L2 core.
 */
void v4l2_prio_open(struct v4l2_prio_state *global, enum v4l2_priority *local);

/**
 * v4l2_prio_close - Implements the priority logic for a file handler close
 *
 * @global: pointer to the &struct v4l2_prio_state of the device node.
 * @local: priority to be released, as defined by enum &v4l2_priority
 *
 * .. note::
 *	This function should be used only by the V4L2 core.
 */
void v4l2_prio_close(struct v4l2_prio_state *global, enum v4l2_priority local);

/**
 * v4l2_prio_max - Return the maximum priority, as stored at the @global array.
 *
 * @global: pointer to the &struct v4l2_prio_state of the device node.
 *
 * .. note::
 *	This function should be used only by the V4L2 core.
 */
enum v4l2_priority v4l2_prio_max(struct v4l2_prio_state *global);

/**
 * v4l2_prio_check - Implements the priority logic for a file handler close
 *
 * @global: pointer to the &struct v4l2_prio_state of the device node.
 * @local: desired priority, as defined by enum &v4l2_priority local
 *
 * .. note::
 *	This function should be used only by the V4L2 core.
 */
int v4l2_prio_check(struct v4l2_prio_state *global, enum v4l2_priority local);

/**
 * struct v4l2_file_operations - fs operations used by a V4L2 device
 *
 * @owner: pointer to struct module
 * @read: operations needed to implement the read() syscall
 * @write: operations needed to implement the write() syscall
 * @poll: operations needed to implement the poll() syscall
 * @unlocked_ioctl: operations needed to implement the ioctl() syscall
 * @compat_ioctl32: operations needed to implement the ioctl() syscall for
 *	the special case where the Kernel uses 64 bits instructions, but
 *	the userspace uses 32 bits.
 * @get_unmapped_area: called by the mmap() syscall, used when %!CONFIG_MMU
 * @mmap: operations needed to implement the mmap() syscall
 * @open: operations needed to implement the open() syscall
 * @release: operations needed to implement the release() syscall
 *
 * .. note::
 *
 *	Those operations are used to implemente the fs struct file_operations
 *	at the V4L2 drivers. The V4L2 core overrides the fs ops with some
 *	extra logic needed by the subsystem.
 */
struct v4l2_file_operations {
	struct module *owner;
	ssize_t (*read) (struct file *, char __user *, size_t, loff_t *);
	ssize_t (*write) (struct file *, const char __user *, size_t, loff_t *);
	__poll_t (*poll) (struct file *, struct poll_table_struct *);
	long (*unlocked_ioctl) (struct file *, unsigned int, unsigned long);
#ifdef CONFIG_COMPAT
	long (*compat_ioctl32) (struct file *, unsigned int, unsigned long);
#endif
	unsigned long (*get_unmapped_area) (struct file *, unsigned long,
				unsigned long, unsigned long, unsigned long);
	int (*mmap) (struct file *, struct vm_area_struct *);
	int (*open) (struct file *);
	int (*release) (struct file *);
};

/*
 * Newer version of video_device, handled by videodev2.c
 *	This version moves redundant code from video device code to
 *	the common handler
 */

/**
 * struct video_device - Structure used to create and manage the V4L2 device
 *	nodes.
 *
 * @entity: &struct media_entity
 * @intf_devnode: pointer to &struct media_intf_devnode
 * @pipe: &struct media_pipeline
 * @fops: pointer to &struct v4l2_file_operations for the video device
 * @device_caps: device capabilities as used in v4l2_capabilities
 * @dev: &struct device for the video device
 * @cdev: character device
 * @v4l2_dev: pointer to &struct v4l2_device parent
 * @dev_parent: pointer to &struct device parent
 * @ctrl_handler: Control handler associated with this device node.
 *	 May be NULL.
 * @queue: &struct vb2_queue associated with this device node. May be NULL.
 * @prio: pointer to &struct v4l2_prio_state with device's Priority state.
 *	 If NULL, then v4l2_dev->prio will be used.
 * @name: video device name
 * @vfl_type: V4L device type, as defined by &enum vfl_devnode_type
 * @vfl_dir: V4L receiver, transmitter or m2m
 * @minor: device node 'minor'. It is set to -1 if the registration failed
 * @num: number of the video device node
 * @flags: video device flags. Use bitops to set/clear/test flags.
 *	   Contains a set of &enum v4l2_video_device_flags.
 * @index: attribute to differentiate multiple indices on one physical device
 * @fh_lock: Lock for all v4l2_fhs
 * @fh_list: List of &struct v4l2_fh
 * @dev_debug: Internal device debug flags, not for use by drivers
 * @tvnorms: Supported tv norms
 *
 * @release: video device release() callback
 * @ioctl_ops: pointer to &struct v4l2_ioctl_ops with ioctl callbacks
 *
 * @valid_ioctls: bitmap with the valid ioctls for this device
 * @disable_locking: bitmap with the ioctls that don't require locking
 * @lock: pointer to &struct mutex serialization lock
 *
 * .. note::
 *	Only set @dev_parent if that can't be deduced from @v4l2_dev.
 */

struct video_device
{
#if defined(CONFIG_MEDIA_CONTROLLER)
	struct media_entity entity;
	struct media_intf_devnode *intf_devnode;
	struct media_pipeline pipe;
#endif
	const struct v4l2_file_operations *fops;

	u32 device_caps;

	/* sysfs */
	struct device dev;
	struct cdev *cdev;

	struct v4l2_device *v4l2_dev;
	struct device *dev_parent;

	struct v4l2_ctrl_handler *ctrl_handler;

	struct vb2_queue *queue;

	struct v4l2_prio_state *prio;

	/* device info */
	char name[32];
	enum vfl_devnode_type vfl_type;
	enum vfl_devnode_direction vfl_dir;
	int minor;
	u16 num;
	unsigned long flags;
	int index;

	/* V4L2 file handles */
	spinlock_t		fh_lock;
	struct list_head	fh_list;

	int dev_debug;

	v4l2_std_id tvnorms;

	/* callbacks */
	void (*release)(struct video_device *vdev);
	const struct v4l2_ioctl_ops *ioctl_ops;
	DECLARE_BITMAP(valid_ioctls, BASE_VIDIOC_PRIVATE);

	DECLARE_BITMAP(disable_locking, BASE_VIDIOC_PRIVATE);
	struct mutex *lock;
};

/**
 * media_entity_to_video_device - Returns a &struct video_device from
 *	the &struct media_entity embedded on it.
 *
 * @entity: pointer to &struct media_entity
 */
#define media_entity_to_video_device(entity) \
	container_of(entity, struct video_device, entity)

/**
 * to_video_device - Returns a &struct video_device from the
 *	&struct device embedded on it.
 *
 * @cd: pointer to &struct device
 */
#define to_video_device(cd) container_of(cd, struct video_device, dev)

/**
 * __video_register_device - register video4linux devices
 *
 * @vdev: struct video_device to register
 * @type: type of device to register, as defined by &enum vfl_devnode_type
 * @nr:   which device node number is desired:
 *	(0 == /dev/video0, 1 == /dev/video1, ..., -1 == first free)
 * @warn_if_nr_in_use: warn if the desired device node number
 *        was already in use and another number was chosen instead.
 * @owner: module that owns the video device node
 *
 * The registration code assigns minor numbers and device node numbers
 * based on the requested type and registers the new device node with
 * the kernel.
 *
 * This function assumes that struct video_device was zeroed when it
 * was allocated and does not contain any stale date.
 *
 * An error is returned if no free minor or device node number could be
 * found, or if the registration of the device node failed.
 *
 * Returns 0 on success.
 *
 * .. note::
 *
 *	This function is meant to be used only inside the V4L2 core.
 *	Drivers should use video_register_device() or
 *	video_register_device_no_warn().
 */
int __must_check __video_register_device(struct video_device *vdev,
					 enum vfl_devnode_type type,
					 int nr, int warn_if_nr_in_use,
					 struct module *owner);

/**
 *  video_register_device - register video4linux devices
 *
 * @vdev: struct video_device to register
 * @type: type of device to register, as defined by &enum vfl_devnode_type
 * @nr:   which device node number is desired:
 *	(0 == /dev/video0, 1 == /dev/video1, ..., -1 == first free)
 *
 * Internally, it calls __video_register_device(). Please see its
 * documentation for more details.
 *
 * .. note::
 *	if video_register_device fails, the release() callback of
 *	&struct video_device structure is *not* called, so the caller
 *	is responsible for freeing any data. Usually that means that
 *	you video_device_release() should be called on failure.
 */
static inline int __must_check video_register_device(struct video_device *vdev,
						     enum vfl_devnode_type type,
						     int nr)
{
	return __video_register_device(vdev, type, nr, 1, vdev->fops->owner);
}

/**
 *  video_register_device_no_warn - register video4linux devices
 *
 * @vdev: struct video_device to register
 * @type: type of device to register, as defined by &enum vfl_devnode_type
 * @nr:   which device node number is desired:
 *	(0 == /dev/video0, 1 == /dev/video1, ..., -1 == first free)
 *
 * This function is identical to video_register_device() except that no
 * warning is issued if the desired device node number was already in use.
 *
 * Internally, it calls __video_register_device(). Please see its
 * documentation for more details.
 *
 * .. note::
 *	if video_register_device fails, the release() callback of
 *	&struct video_device structure is *not* called, so the caller
 *	is responsible for freeing any data. Usually that means that
 *	you video_device_release() should be called on failure.
 */
static inline int __must_check
video_register_device_no_warn(struct video_device *vdev,
			      enum vfl_devnode_type type, int nr)
{
	return __video_register_device(vdev, type, nr, 0, vdev->fops->owner);
}

/**
 * video_unregister_device - Unregister video devices.
 *
 * @vdev: &struct video_device to register
 *
 * Does nothing if vdev == NULL or if video_is_registered() returns false.
 */
void video_unregister_device(struct video_device *vdev);

/**
 * video_device_alloc - helper function to alloc &struct video_device
 *
 * Returns NULL if %-ENOMEM or a &struct video_device on success.
 */
struct video_device * __must_check video_device_alloc(void);

/**
 * video_device_release - helper function to release &struct video_device
 *
 * @vdev: pointer to &struct video_device
 *
 * Can also be used for video_device->release\(\).
 */
void video_device_release(struct video_device *vdev);

/**
 * video_device_release_empty - helper function to implement the
 *	video_device->release\(\) callback.
 *
 * @vdev: pointer to &struct video_device
 *
 * This release function does nothing.
 *
 * It should be used when the video_device is a static global struct.
 *
 * .. note::
 *	Having a static video_device is a dubious construction at best.
 */
void video_device_release_empty(struct video_device *vdev);

/**
 * v4l2_is_known_ioctl - Checks if a given cmd is a known V4L ioctl
 *
 * @cmd: ioctl command
 *
 * returns true if cmd is a known V4L2 ioctl
 */
bool v4l2_is_known_ioctl(unsigned int cmd);

/** v4l2_disable_ioctl_locking - mark that a given command
 *	shouldn't use core locking
 *
 * @vdev: pointer to &struct video_device
 * @cmd: ioctl command
 */
static inline void v4l2_disable_ioctl_locking(struct video_device *vdev,
					      unsigned int cmd)
{
	if (_IOC_NR(cmd) < BASE_VIDIOC_PRIVATE)
		set_bit(_IOC_NR(cmd), vdev->disable_locking);
}

/**
 * v4l2_disable_ioctl- mark that a given command isn't implemented.
 *	shouldn't use core locking
 *
 * @vdev: pointer to &struct video_device
 * @cmd: ioctl command
 *
 * This function allows drivers to provide just one v4l2_ioctl_ops struct, but
 * disable ioctls based on the specific card that is actually found.
 *
 * .. note::
 *
 *    This must be called before video_register_device.
 *    See also the comments for determine_valid_ioctls().
 */
static inline void v4l2_disable_ioctl(struct video_device *vdev,
				      unsigned int cmd)
{
	if (_IOC_NR(cmd) < BASE_VIDIOC_PRIVATE)
		set_bit(_IOC_NR(cmd), vdev->valid_ioctls);
}

/**
 * video_get_drvdata - gets private data from &struct video_device.
 *
 * @vdev: pointer to &struct video_device
 *
 * returns a pointer to the private data
 */
static inline void *video_get_drvdata(struct video_device *vdev)
{
	return dev_get_drvdata(&vdev->dev);
}

/**
 * video_set_drvdata - sets private data from &struct video_device.
 *
 * @vdev: pointer to &struct video_device
 * @data: private data pointer
 */
static inline void video_set_drvdata(struct video_device *vdev, void *data)
{
	dev_set_drvdata(&vdev->dev, data);
}

/**
 * video_devdata - gets &struct video_device from struct file.
 *
 * @file: pointer to struct file
 */
struct video_device *video_devdata(struct file *file);

/**
 * video_drvdata - gets private data from &struct video_device using the
 *	struct file.
 *
 * @file: pointer to struct file
 *
 * This is function combines both video_get_drvdata() and video_devdata()
 * as this is used very often.
 */
static inline void *video_drvdata(struct file *file)
{
	return video_get_drvdata(video_devdata(file));
}

/**
 * video_device_node_name - returns the video device name
 *
 * @vdev: pointer to &struct video_device
 *
 * Returns the device name string
 */
static inline const char *video_device_node_name(struct video_device *vdev)
{
	return dev_name(&vdev->dev);
}

/**
 * video_is_registered - returns true if the &struct video_device is registered.
 *
 *
 * @vdev: pointer to &struct video_device
 */
static inline int video_is_registered(struct video_device *vdev)
{
	return test_bit(V4L2_FL_REGISTERED, &vdev->flags);
}

#endif /* _V4L2_DEV_H */
OpenPOWER on IntegriCloud