1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * v4l2-fh.c
4 *
5 * V4L2 file handles.
6 *
7 * Copyright (C) 2009--2010 Nokia Corporation.
8 *
9 * Contact: Sakari Ailus <sakari.ailus@iki.fi>
10 */
11
12#include <linux/bitops.h>
13#include <linux/slab.h>
14#include <linux/export.h>
15#include <media/v4l2-dev.h>
16#include <media/v4l2-fh.h>
17#include <media/v4l2-event.h>
18#include <media/v4l2-ioctl.h>
19#include <media/v4l2-mc.h>
20
21void v4l2_fh_init(struct v4l2_fh *fh, struct video_device *vdev)
22{
23	fh->vdev = vdev;
24	/* Inherit from video_device. May be overridden by the driver. */
25	fh->ctrl_handler = vdev->ctrl_handler;
26	INIT_LIST_HEAD(&fh->list);
27	set_bit(V4L2_FL_USES_V4L2_FH, &fh->vdev->flags);
28	/*
29	 * determine_valid_ioctls() does not know if struct v4l2_fh
30	 * is used by this driver, but here we do. So enable the
31	 * prio ioctls here.
32	 */
33	set_bit(_IOC_NR(VIDIOC_G_PRIORITY), vdev->valid_ioctls);
34	set_bit(_IOC_NR(VIDIOC_S_PRIORITY), vdev->valid_ioctls);
35	fh->prio = V4L2_PRIORITY_UNSET;
36	init_waitqueue_head(&fh->wait);
37	INIT_LIST_HEAD(&fh->available);
38	INIT_LIST_HEAD(&fh->subscribed);
39	fh->sequence = -1;
40	mutex_init(&fh->subscribe_lock);
41}
42EXPORT_SYMBOL_GPL(v4l2_fh_init);
43
44void v4l2_fh_add(struct v4l2_fh *fh)
45{
46	unsigned long flags;
47
48	v4l2_prio_open(fh->vdev->prio, &fh->prio);
49	spin_lock_irqsave(&fh->vdev->fh_lock, flags);
50	list_add(&fh->list, &fh->vdev->fh_list);
51	spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
52}
53EXPORT_SYMBOL_GPL(v4l2_fh_add);
54
55int v4l2_fh_open(struct file *filp)
56{
57	struct video_device *vdev = video_devdata(filp);
58	struct v4l2_fh *fh = kzalloc(sizeof(*fh), GFP_KERNEL);
59
60	filp->private_data = fh;
61	if (fh == NULL)
62		return -ENOMEM;
63	v4l2_fh_init(fh, vdev);
64	v4l2_fh_add(fh);
65	return 0;
66}
67EXPORT_SYMBOL_GPL(v4l2_fh_open);
68
69void v4l2_fh_del(struct v4l2_fh *fh)
70{
71	unsigned long flags;
72
73	spin_lock_irqsave(&fh->vdev->fh_lock, flags);
74	list_del_init(&fh->list);
75	spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
76	v4l2_prio_close(fh->vdev->prio, fh->prio);
77}
78EXPORT_SYMBOL_GPL(v4l2_fh_del);
79
80void v4l2_fh_exit(struct v4l2_fh *fh)
81{
82	if (fh->vdev == NULL)
83		return;
84	v4l_disable_media_source(fh->vdev);
85	v4l2_event_unsubscribe_all(fh);
86	mutex_destroy(&fh->subscribe_lock);
87	fh->vdev = NULL;
88}
89EXPORT_SYMBOL_GPL(v4l2_fh_exit);
90
91int v4l2_fh_release(struct file *filp)
92{
93	struct v4l2_fh *fh = filp->private_data;
94
95	if (fh) {
96		v4l2_fh_del(fh);
97		v4l2_fh_exit(fh);
98		kfree(fh);
99		filp->private_data = NULL;
100	}
101	return 0;
102}
103EXPORT_SYMBOL_GPL(v4l2_fh_release);
104
105int v4l2_fh_is_singular(struct v4l2_fh *fh)
106{
107	unsigned long flags;
108	int is_singular;
109
110	if (fh == NULL || fh->vdev == NULL)
111		return 0;
112	spin_lock_irqsave(&fh->vdev->fh_lock, flags);
113	is_singular = list_is_singular(&fh->list);
114	spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
115	return is_singular;
116}
117EXPORT_SYMBOL_GPL(v4l2_fh_is_singular);
118