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
v4l2_fh_init(struct v4l2_fh * fh,struct video_device * vdev)21 void 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 }
42 EXPORT_SYMBOL_GPL(v4l2_fh_init);
43
v4l2_fh_add(struct v4l2_fh * fh,struct file * filp)44 void v4l2_fh_add(struct v4l2_fh *fh, struct file *filp)
45 {
46 unsigned long flags;
47
48 filp->private_data = fh;
49
50 v4l2_prio_open(fh->vdev->prio, &fh->prio);
51 spin_lock_irqsave(&fh->vdev->fh_lock, flags);
52 list_add(&fh->list, &fh->vdev->fh_list);
53 spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
54 }
55 EXPORT_SYMBOL_GPL(v4l2_fh_add);
56
v4l2_fh_open(struct file * filp)57 int v4l2_fh_open(struct file *filp)
58 {
59 struct video_device *vdev = video_devdata(filp);
60 struct v4l2_fh *fh = kzalloc_obj(*fh);
61
62 if (fh == NULL)
63 return -ENOMEM;
64 v4l2_fh_init(fh, vdev);
65 v4l2_fh_add(fh, filp);
66 return 0;
67 }
68 EXPORT_SYMBOL_GPL(v4l2_fh_open);
69
v4l2_fh_del(struct v4l2_fh * fh,struct file * filp)70 void v4l2_fh_del(struct v4l2_fh *fh, struct file *filp)
71 {
72 unsigned long flags;
73
74 spin_lock_irqsave(&fh->vdev->fh_lock, flags);
75 list_del_init(&fh->list);
76 spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
77 v4l2_prio_close(fh->vdev->prio, fh->prio);
78
79 filp->private_data = NULL;
80 }
81 EXPORT_SYMBOL_GPL(v4l2_fh_del);
82
v4l2_fh_exit(struct v4l2_fh * fh)83 void v4l2_fh_exit(struct v4l2_fh *fh)
84 {
85 if (fh->vdev == NULL)
86 return;
87 v4l_disable_media_source(fh->vdev);
88 v4l2_event_unsubscribe_all(fh);
89 mutex_destroy(&fh->subscribe_lock);
90 fh->vdev = NULL;
91 }
92 EXPORT_SYMBOL_GPL(v4l2_fh_exit);
93
v4l2_fh_release(struct file * filp)94 int v4l2_fh_release(struct file *filp)
95 {
96 struct v4l2_fh *fh = file_to_v4l2_fh(filp);
97
98 if (fh) {
99 v4l2_fh_del(fh, filp);
100 v4l2_fh_exit(fh);
101 kfree(fh);
102 }
103 return 0;
104 }
105 EXPORT_SYMBOL_GPL(v4l2_fh_release);
106
v4l2_fh_is_singular(struct v4l2_fh * fh)107 int v4l2_fh_is_singular(struct v4l2_fh *fh)
108 {
109 unsigned long flags;
110 int is_singular;
111
112 if (fh == NULL || fh->vdev == NULL)
113 return 0;
114 spin_lock_irqsave(&fh->vdev->fh_lock, flags);
115 is_singular = list_is_singular(&fh->list);
116 spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
117 return is_singular;
118 }
119 EXPORT_SYMBOL_GPL(v4l2_fh_is_singular);
120