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/**
 25 * enum vfl_devnode_type - type of V4L2 device node
 26 *
 27 * @VFL_TYPE_VIDEO:	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 */
 35enum vfl_devnode_type {
 36	VFL_TYPE_VIDEO,
 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_devnode_direction - Identifies if a &struct video_device
 47 * 	corresponds 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 */
 55enum vfl_devnode_direction {
 56	VFL_DIR_RX,
 57	VFL_DIR_TX,
 58	VFL_DIR_M2M,
 59};
 60
 61struct v4l2_ioctl_callbacks;
 62struct video_device;
 63struct v4l2_device;
 64struct v4l2_ctrl_handler;
 65struct dentry;
 66
 67/**
 68 * enum v4l2_video_device_flags - Flags used by &struct video_device
 69 *
 70 * @V4L2_FL_REGISTERED:
 71 *	indicates that a &struct video_device is registered.
 72 *	Drivers can clear this flag if they want to block all future
 73 *	device access. It is cleared by video_unregister_device.
 74 * @V4L2_FL_USES_V4L2_FH:
 75 *	indicates that file->private_data points to &struct v4l2_fh.
 76 *	This flag is set by the core when v4l2_fh_init() is called.
 77 *	All drivers must use it.
 78 * @V4L2_FL_QUIRK_INVERTED_CROP:
 79 *	some old M2M drivers use g/s_crop/cropcap incorrectly: crop and
 80 *	compose are swapped. If this flag is set, then the selection
 81 *	targets are swapped in the g/s_crop/cropcap functions in v4l2-ioctl.c.
 82 *	This allows those drivers to correctly implement the selection API,
 83 *	but the old crop API will still work as expected in order to preserve
 84 *	backwards compatibility.
 85 *	Never set this flag for new drivers.
 86 * @V4L2_FL_SUBDEV_RO_DEVNODE:
 87 *	indicates that the video device node is registered in read-only mode.
 88 *	The flag only applies to device nodes registered for sub-devices, it is
 89 *	set by the core when the sub-devices device nodes are registered with
 90 *	v4l2_device_register_ro_subdev_nodes() and used by the sub-device ioctl
 91 *	handler to restrict access to some ioctl calls.
 92 */
 93enum v4l2_video_device_flags {
 94	V4L2_FL_REGISTERED		= 0,
 95	V4L2_FL_USES_V4L2_FH		= 1,
 96	V4L2_FL_QUIRK_INVERTED_CROP	= 2,
 97	V4L2_FL_SUBDEV_RO_DEVNODE	= 3,
 98};
 99
100/* Priority helper functions */
101
102/**
103 * struct v4l2_prio_state - stores the priority states
104 *
105 * @prios: array with elements to store the array priorities
106 *
107 *
108 * .. note::
109 *    The size of @prios array matches the number of priority types defined
110 *    by enum &v4l2_priority.
111 */
112struct v4l2_prio_state {
113	atomic_t prios[4];
114};
115
116/**
117 * v4l2_prio_init - initializes a struct v4l2_prio_state
118 *
119 * @global: pointer to &struct v4l2_prio_state
120 */
121void v4l2_prio_init(struct v4l2_prio_state *global);
122
123/**
124 * v4l2_prio_change - changes the v4l2 file handler priority
125 *
126 * @global: pointer to the &struct v4l2_prio_state of the device node.
127 * @local: pointer to the desired priority, as defined by enum &v4l2_priority
128 * @new: Priority type requested, as defined by enum &v4l2_priority.
129 *
130 * .. note::
131 *	This function should be used only by the V4L2 core.
132 */
133int v4l2_prio_change(struct v4l2_prio_state *global, enum v4l2_priority *local,
134		     enum v4l2_priority new);
135
136/**
137 * v4l2_prio_open - Implements the priority logic for a file handler open
138 *
139 * @global: pointer to the &struct v4l2_prio_state of the device node.
140 * @local: pointer to the desired priority, as defined by enum &v4l2_priority
141 *
142 * .. note::
143 *	This function should be used only by the V4L2 core.
144 */
145void v4l2_prio_open(struct v4l2_prio_state *global, enum v4l2_priority *local);
146
147/**
148 * v4l2_prio_close - Implements the priority logic for a file handler close
149 *
150 * @global: pointer to the &struct v4l2_prio_state of the device node.
151 * @local: priority to be released, as defined by enum &v4l2_priority
152 *
153 * .. note::
154 *	This function should be used only by the V4L2 core.
155 */
156void v4l2_prio_close(struct v4l2_prio_state *global, enum v4l2_priority local);
157
158/**
159 * v4l2_prio_max - Return the maximum priority, as stored at the @global array.
160 *
161 * @global: pointer to the &struct v4l2_prio_state of the device node.
162 *
163 * .. note::
164 *	This function should be used only by the V4L2 core.
165 */
166enum v4l2_priority v4l2_prio_max(struct v4l2_prio_state *global);
167
168/**
169 * v4l2_prio_check - Implements the priority logic for a file handler close
170 *
171 * @global: pointer to the &struct v4l2_prio_state of the device node.
172 * @local: desired priority, as defined by enum &v4l2_priority local
173 *
174 * .. note::
175 *	This function should be used only by the V4L2 core.
176 */
177int v4l2_prio_check(struct v4l2_prio_state *global, enum v4l2_priority local);
178
179/**
180 * struct v4l2_file_operations - fs operations used by a V4L2 device
181 *
182 * @owner: pointer to struct module
183 * @read: operations needed to implement the read() syscall
184 * @write: operations needed to implement the write() syscall
185 * @poll: operations needed to implement the poll() syscall
186 * @unlocked_ioctl: operations needed to implement the ioctl() syscall
187 * @compat_ioctl32: operations needed to implement the ioctl() syscall for
188 *	the special case where the Kernel uses 64 bits instructions, but
189 *	the userspace uses 32 bits.
190 * @get_unmapped_area: called by the mmap() syscall, used when %!CONFIG_MMU
191 * @mmap: operations needed to implement the mmap() syscall
192 * @open: operations needed to implement the open() syscall
193 * @release: operations needed to implement the release() syscall
194 *
195 * .. note::
196 *
197 *	Those operations are used to implemente the fs struct file_operations
198 *	at the V4L2 drivers. The V4L2 core overrides the fs ops with some
199 *	extra logic needed by the subsystem.
200 */
201struct v4l2_file_operations {
202	struct module *owner;
203	ssize_t (*read) (struct file *, char __user *, size_t, loff_t *);
204	ssize_t (*write) (struct file *, const char __user *, size_t, loff_t *);
205	__poll_t (*poll) (struct file *, struct poll_table_struct *);
206	long (*unlocked_ioctl) (struct file *, unsigned int, unsigned long);
207#ifdef CONFIG_COMPAT
208	long (*compat_ioctl32) (struct file *, unsigned int, unsigned long);
209#endif
210	unsigned long (*get_unmapped_area) (struct file *, unsigned long,
211				unsigned long, unsigned long, unsigned long);
212	int (*mmap) (struct file *, struct vm_area_struct *);
213	int (*open) (struct file *);
214	int (*release) (struct file *);
215};
216
217/*
218 * Newer version of video_device, handled by videodev2.c
219 *	This version moves redundant code from video device code to
220 *	the common handler
221 */
222
223/**
224 * struct video_device - Structure used to create and manage the V4L2 device
225 *	nodes.
226 *
227 * @entity: &struct media_entity
228 * @intf_devnode: pointer to &struct media_intf_devnode
229 * @pipe: &struct media_pipeline
230 * @fops: pointer to &struct v4l2_file_operations for the video device
231 * @device_caps: device capabilities as used in v4l2_capabilities
232 * @dev: &struct device for the video device
233 * @cdev: character device
234 * @v4l2_dev: pointer to &struct v4l2_device parent
235 * @dev_parent: pointer to &struct device parent
236 * @ctrl_handler: Control handler associated with this device node.
237 *	 May be NULL.
238 * @queue: &struct vb2_queue associated with this device node. May be NULL.
239 * @prio: pointer to &struct v4l2_prio_state with device's Priority state.
240 *	 If NULL, then v4l2_dev->prio will be used.
241 * @name: video device name
242 * @vfl_type: V4L device type, as defined by &enum vfl_devnode_type
243 * @vfl_dir: V4L receiver, transmitter or m2m
244 * @minor: device node 'minor'. It is set to -1 if the registration failed
245 * @num: number of the video device node
246 * @flags: video device flags. Use bitops to set/clear/test flags.
247 *	   Contains a set of &enum v4l2_video_device_flags.
248 * @index: attribute to differentiate multiple indices on one physical device
249 * @fh_lock: Lock for all v4l2_fhs
250 * @fh_list: List of &struct v4l2_fh
251 * @dev_debug: Internal device debug flags, not for use by drivers
252 * @tvnorms: Supported tv norms
253 *
254 * @release: video device release() callback
255 * @ioctl_ops: pointer to &struct v4l2_ioctl_ops with ioctl callbacks
256 *
257 * @valid_ioctls: bitmap with the valid ioctls for this device
258 * @lock: pointer to &struct mutex serialization lock
259 *
260 * .. note::
261 *	Only set @dev_parent if that can't be deduced from @v4l2_dev.
262 */
263
264struct video_device {
265#if defined(CONFIG_MEDIA_CONTROLLER)
266	struct media_entity entity;
267	struct media_intf_devnode *intf_devnode;
268	struct media_pipeline pipe;
269#endif
270	const struct v4l2_file_operations *fops;
271
272	u32 device_caps;
273
274	/* sysfs */
275	struct device dev;
276	struct cdev *cdev;
277
278	struct v4l2_device *v4l2_dev;
279	struct device *dev_parent;
280
281	struct v4l2_ctrl_handler *ctrl_handler;
282
283	struct vb2_queue *queue;
284
285	struct v4l2_prio_state *prio;
286
287	/* device info */
288	char name[64];
289	enum vfl_devnode_type vfl_type;
290	enum vfl_devnode_direction vfl_dir;
291	int minor;
292	u16 num;
293	unsigned long flags;
294	int index;
295
296	/* V4L2 file handles */
297	spinlock_t		fh_lock;
298	struct list_head	fh_list;
299
300	int dev_debug;
301
302	v4l2_std_id tvnorms;
303
304	/* callbacks */
305	void (*release)(struct video_device *vdev);
306	const struct v4l2_ioctl_ops *ioctl_ops;
307	DECLARE_BITMAP(valid_ioctls, BASE_VIDIOC_PRIVATE);
308
309	struct mutex *lock;
310};
311
312/**
313 * media_entity_to_video_device - Returns a &struct video_device from
314 *	the &struct media_entity embedded on it.
315 *
316 * @__entity: pointer to &struct media_entity, may be NULL
317 */
318#define media_entity_to_video_device(__entity)				\
319({									\
320	typeof(__entity) __me_vdev_ent = __entity;			\
321									\
322	__me_vdev_ent ?							\
323		container_of_const(__me_vdev_ent,  struct video_device, \
324				   entity) : NULL;			\
325})
326
327/**
328 * to_video_device - Returns a &struct video_device from the
329 *	&struct device embedded on it.
330 *
331 * @cd: pointer to &struct device
332 */
333#define to_video_device(cd) container_of_const(cd, struct video_device, dev)
334
335/**
336 * __video_register_device - register video4linux devices
337 *
338 * @vdev: struct video_device to register
339 * @type: type of device to register, as defined by &enum vfl_devnode_type
340 * @nr:   which device node number is desired:
341 *	(0 == /dev/video0, 1 == /dev/video1, ..., -1 == first free)
342 * @warn_if_nr_in_use: warn if the desired device node number
343 *        was already in use and another number was chosen instead.
344 * @owner: module that owns the video device node
345 *
346 * The registration code assigns minor numbers and device node numbers
347 * based on the requested type and registers the new device node with
348 * the kernel.
349 *
350 * This function assumes that struct video_device was zeroed when it
351 * was allocated and does not contain any stale date.
352 *
353 * An error is returned if no free minor or device node number could be
354 * found, or if the registration of the device node failed.
355 *
356 * Returns 0 on success.
357 *
358 * .. note::
359 *
360 *	This function is meant to be used only inside the V4L2 core.
361 *	Drivers should use video_register_device() or
362 *	video_register_device_no_warn().
363 */
364int __must_check __video_register_device(struct video_device *vdev,
365					 enum vfl_devnode_type type,
366					 int nr, int warn_if_nr_in_use,
367					 struct module *owner);
368
369/**
370 *  video_register_device - register video4linux devices
371 *
372 * @vdev: struct video_device to register
373 * @type: type of device to register, as defined by &enum vfl_devnode_type
374 * @nr:   which device node number is desired:
375 *	(0 == /dev/video0, 1 == /dev/video1, ..., -1 == first free)
376 *
377 * Internally, it calls __video_register_device(). Please see its
378 * documentation for more details.
379 *
380 * .. note::
381 *	if video_register_device fails, the release() callback of
382 *	&struct video_device structure is *not* called, so the caller
383 *	is responsible for freeing any data. Usually that means that
384 *	you video_device_release() should be called on failure.
385 */
386static inline int __must_check video_register_device(struct video_device *vdev,
387						     enum vfl_devnode_type type,
388						     int nr)
389{
390	return __video_register_device(vdev, type, nr, 1, vdev->fops->owner);
391}
392
393/**
394 *  video_register_device_no_warn - register video4linux devices
395 *
396 * @vdev: struct video_device to register
397 * @type: type of device to register, as defined by &enum vfl_devnode_type
398 * @nr:   which device node number is desired:
399 *	(0 == /dev/video0, 1 == /dev/video1, ..., -1 == first free)
400 *
401 * This function is identical to video_register_device() except that no
402 * warning is issued if the desired device node number was already in use.
403 *
404 * Internally, it calls __video_register_device(). Please see its
405 * documentation for more details.
406 *
407 * .. note::
408 *	if video_register_device fails, the release() callback of
409 *	&struct video_device structure is *not* called, so the caller
410 *	is responsible for freeing any data. Usually that means that
411 *	you video_device_release() should be called on failure.
412 */
413static inline int __must_check
414video_register_device_no_warn(struct video_device *vdev,
415			      enum vfl_devnode_type type, int nr)
416{
417	return __video_register_device(vdev, type, nr, 0, vdev->fops->owner);
418}
419
420/**
421 * video_unregister_device - Unregister video devices.
422 *
423 * @vdev: &struct video_device to register
424 *
425 * Does nothing if vdev == NULL or if video_is_registered() returns false.
426 */
427void video_unregister_device(struct video_device *vdev);
428
429/**
430 * video_device_alloc - helper function to alloc &struct video_device
431 *
432 * Returns NULL if %-ENOMEM or a &struct video_device on success.
433 */
434struct video_device * __must_check video_device_alloc(void);
435
436/**
437 * video_device_release - helper function to release &struct video_device
438 *
439 * @vdev: pointer to &struct video_device
440 *
441 * Can also be used for video_device->release\(\).
442 */
443void video_device_release(struct video_device *vdev);
444
445/**
446 * video_device_release_empty - helper function to implement the
447 *	video_device->release\(\) callback.
448 *
449 * @vdev: pointer to &struct video_device
450 *
451 * This release function does nothing.
452 *
453 * It should be used when the video_device is a static global struct.
454 *
455 * .. note::
456 *	Having a static video_device is a dubious construction at best.
457 */
458void video_device_release_empty(struct video_device *vdev);
459
460/**
461 * v4l2_disable_ioctl- mark that a given command isn't implemented.
462 *	shouldn't use core locking
463 *
464 * @vdev: pointer to &struct video_device
465 * @cmd: ioctl command
466 *
467 * This function allows drivers to provide just one v4l2_ioctl_ops struct, but
468 * disable ioctls based on the specific card that is actually found.
469 *
470 * .. note::
471 *
472 *    This must be called before video_register_device.
473 *    See also the comments for determine_valid_ioctls().
474 */
475static inline void v4l2_disable_ioctl(struct video_device *vdev,
476				      unsigned int cmd)
477{
478	if (_IOC_NR(cmd) < BASE_VIDIOC_PRIVATE)
479		set_bit(_IOC_NR(cmd), vdev->valid_ioctls);
480}
481
482/**
483 * video_get_drvdata - gets private data from &struct video_device.
484 *
485 * @vdev: pointer to &struct video_device
486 *
487 * returns a pointer to the private data
488 */
489static inline void *video_get_drvdata(struct video_device *vdev)
490{
491	return dev_get_drvdata(&vdev->dev);
492}
493
494/**
495 * video_set_drvdata - sets private data from &struct video_device.
496 *
497 * @vdev: pointer to &struct video_device
498 * @data: private data pointer
499 */
500static inline void video_set_drvdata(struct video_device *vdev, void *data)
501{
502	dev_set_drvdata(&vdev->dev, data);
503}
504
505/**
506 * video_devdata - gets &struct video_device from struct file.
507 *
508 * @file: pointer to struct file
509 */
510struct video_device *video_devdata(struct file *file);
511
512/**
513 * video_drvdata - gets private data from &struct video_device using the
514 *	struct file.
515 *
516 * @file: pointer to struct file
517 *
518 * This is function combines both video_get_drvdata() and video_devdata()
519 * as this is used very often.
520 */
521static inline void *video_drvdata(struct file *file)
522{
523	return video_get_drvdata(video_devdata(file));
524}
525
526/**
527 * video_device_node_name - returns the video device name
528 *
529 * @vdev: pointer to &struct video_device
530 *
531 * Returns the device name string
532 */
533static inline const char *video_device_node_name(struct video_device *vdev)
534{
535	return dev_name(&vdev->dev);
536}
537
538/**
539 * video_is_registered - returns true if the &struct video_device is registered.
540 *
541 *
542 * @vdev: pointer to &struct video_device
543 */
544static inline int video_is_registered(struct video_device *vdev)
545{
546	return test_bit(V4L2_FL_REGISTERED, &vdev->flags);
547}
548
549/**
550 * v4l2_debugfs_root - returns the dentry of the top-level "v4l2" debugfs dir
551 *
552 * If this directory does not yet exist, then it will be created.
553 */
554#ifdef CONFIG_DEBUG_FS
555struct dentry *v4l2_debugfs_root(void);
556#else
557static inline struct dentry *v4l2_debugfs_root(void)
558{
559	return NULL;
560}
561#endif
562
563#if defined(CONFIG_MEDIA_CONTROLLER)
564
565/**
566 * video_device_pipeline_start - Mark a pipeline as streaming
567 * @vdev: Starting video device
568 * @pipe: Media pipeline to be assigned to all entities in the pipeline.
569 *
570 * Mark all entities connected to a given video device through enabled links,
571 * either directly or indirectly, as streaming. The given pipeline object is
572 * assigned to every pad in the pipeline and stored in the media_pad pipe
573 * field.
574 *
575 * Calls to this function can be nested, in which case the same number of
576 * video_device_pipeline_stop() calls will be required to stop streaming. The
577 * pipeline pointer must be identical for all nested calls to
578 * video_device_pipeline_start().
579 *
580 * The video device must contain a single pad.
581 *
582 * This is a convenience wrapper around media_pipeline_start().
583 */
584__must_check int video_device_pipeline_start(struct video_device *vdev,
585					     struct media_pipeline *pipe);
586
587/**
588 * __video_device_pipeline_start - Mark a pipeline as streaming
589 * @vdev: Starting video device
590 * @pipe: Media pipeline to be assigned to all entities in the pipeline.
591 *
592 * ..note:: This is the non-locking version of video_device_pipeline_start()
593 *
594 * The video device must contain a single pad.
595 *
596 * This is a convenience wrapper around __media_pipeline_start().
597 */
598__must_check int __video_device_pipeline_start(struct video_device *vdev,
599					       struct media_pipeline *pipe);
600
601/**
602 * video_device_pipeline_stop - Mark a pipeline as not streaming
603 * @vdev: Starting video device
604 *
605 * Mark all entities connected to a given video device through enabled links,
606 * either directly or indirectly, as not streaming. The media_pad pipe field
607 * is reset to %NULL.
608 *
609 * If multiple calls to media_pipeline_start() have been made, the same
610 * number of calls to this function are required to mark the pipeline as not
611 * streaming.
612 *
613 * The video device must contain a single pad.
614 *
615 * This is a convenience wrapper around media_pipeline_stop().
616 */
617void video_device_pipeline_stop(struct video_device *vdev);
618
619/**
620 * __video_device_pipeline_stop - Mark a pipeline as not streaming
621 * @vdev: Starting video device
622 *
623 * .. note:: This is the non-locking version of media_pipeline_stop()
624 *
625 * The video device must contain a single pad.
626 *
627 * This is a convenience wrapper around __media_pipeline_stop().
628 */
629void __video_device_pipeline_stop(struct video_device *vdev);
630
631/**
632 * video_device_pipeline_alloc_start - Mark a pipeline as streaming
633 * @vdev: Starting video device
634 *
635 * video_device_pipeline_alloc_start() is similar to video_device_pipeline_start()
636 * but instead of working on a given pipeline the function will use an
637 * existing pipeline if the video device is already part of a pipeline, or
638 * allocate a new pipeline.
639 *
640 * Calls to video_device_pipeline_alloc_start() must be matched with
641 * video_device_pipeline_stop().
642 */
643__must_check int video_device_pipeline_alloc_start(struct video_device *vdev);
644
645/**
646 * video_device_pipeline - Get the media pipeline a video device is part of
647 * @vdev: The video device
648 *
649 * This function returns the media pipeline that a video device has been
650 * associated with when constructing the pipeline with
651 * video_device_pipeline_start(). The pointer remains valid until
652 * video_device_pipeline_stop() is called.
653 *
654 * Return: The media_pipeline the video device is part of, or NULL if the video
655 * device is not part of any pipeline.
656 *
657 * The video device must contain a single pad.
658 *
659 * This is a convenience wrapper around media_entity_pipeline().
660 */
661struct media_pipeline *video_device_pipeline(struct video_device *vdev);
662
663#endif /* CONFIG_MEDIA_CONTROLLER */
664
665#endif /* _V4L2_DEV_H */