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)44 void 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 }
53 EXPORT_SYMBOL_GPL(v4l2_fh_add);
54
v4l2_fh_open(struct file * filp)55 int 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 }
67 EXPORT_SYMBOL_GPL(v4l2_fh_open);
68
v4l2_fh_del(struct v4l2_fh * fh)69 void 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 }
78 EXPORT_SYMBOL_GPL(v4l2_fh_del);
79
v4l2_fh_exit(struct v4l2_fh * fh)80 void 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 }
89 EXPORT_SYMBOL_GPL(v4l2_fh_exit);
90
v4l2_fh_release(struct file * filp)91 int 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 }
103 EXPORT_SYMBOL_GPL(v4l2_fh_release);
104
v4l2_fh_is_singular(struct v4l2_fh * fh)105 int 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 }
117 EXPORT_SYMBOL_GPL(v4l2_fh_is_singular);
118