1 /*
2 * v4l2-fh.c
3 *
4 * V4L2 file handles.
5 *
6 * Copyright (C) 2009--2010 Nokia Corporation.
7 *
8 * Contact: Sakari Ailus <sakari.ailus@iki.fi>
9 *
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License
12 * version 2 as published by the Free Software Foundation.
13 *
14 * This program is distributed in the hope that it will be useful, but
15 * WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17 * General Public License for more details.
18 */
19
20 #include <linux/bitops.h>
21 #include <linux/slab.h>
22 #include <linux/export.h>
23 #include <media/v4l2-dev.h>
24 #include <media/v4l2-fh.h>
25 #include <media/v4l2-event.h>
26 #include <media/v4l2-ioctl.h>
27 #include <media/v4l2-mc.h>
28
v4l2_fh_init(struct v4l2_fh * fh,struct video_device * vdev)29 void v4l2_fh_init(struct v4l2_fh *fh, struct video_device *vdev)
30 {
31 fh->vdev = vdev;
32 /* Inherit from video_device. May be overridden by the driver. */
33 fh->ctrl_handler = vdev->ctrl_handler;
34 INIT_LIST_HEAD(&fh->list);
35 set_bit(V4L2_FL_USES_V4L2_FH, &fh->vdev->flags);
36 /*
37 * determine_valid_ioctls() does not know if struct v4l2_fh
38 * is used by this driver, but here we do. So enable the
39 * prio ioctls here.
40 */
41 set_bit(_IOC_NR(VIDIOC_G_PRIORITY), vdev->valid_ioctls);
42 set_bit(_IOC_NR(VIDIOC_S_PRIORITY), vdev->valid_ioctls);
43 fh->prio = V4L2_PRIORITY_UNSET;
44 init_waitqueue_head(&fh->wait);
45 INIT_LIST_HEAD(&fh->available);
46 INIT_LIST_HEAD(&fh->subscribed);
47 fh->sequence = -1;
48 mutex_init(&fh->subscribe_lock);
49 }
50 EXPORT_SYMBOL_GPL(v4l2_fh_init);
51
v4l2_fh_add(struct v4l2_fh * fh)52 void v4l2_fh_add(struct v4l2_fh *fh)
53 {
54 unsigned long flags;
55
56 v4l2_prio_open(fh->vdev->prio, &fh->prio);
57 spin_lock_irqsave(&fh->vdev->fh_lock, flags);
58 list_add(&fh->list, &fh->vdev->fh_list);
59 spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
60 }
61 EXPORT_SYMBOL_GPL(v4l2_fh_add);
62
v4l2_fh_open(struct file * filp)63 int v4l2_fh_open(struct file *filp)
64 {
65 struct video_device *vdev = video_devdata(filp);
66 struct v4l2_fh *fh = kzalloc(sizeof(*fh), GFP_KERNEL);
67
68 filp->private_data = fh;
69 if (fh == NULL)
70 return -ENOMEM;
71 v4l2_fh_init(fh, vdev);
72 v4l2_fh_add(fh);
73 return 0;
74 }
75 EXPORT_SYMBOL_GPL(v4l2_fh_open);
76
v4l2_fh_del(struct v4l2_fh * fh)77 void v4l2_fh_del(struct v4l2_fh *fh)
78 {
79 unsigned long flags;
80
81 spin_lock_irqsave(&fh->vdev->fh_lock, flags);
82 list_del_init(&fh->list);
83 spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
84 v4l2_prio_close(fh->vdev->prio, fh->prio);
85 }
86 EXPORT_SYMBOL_GPL(v4l2_fh_del);
87
v4l2_fh_exit(struct v4l2_fh * fh)88 void v4l2_fh_exit(struct v4l2_fh *fh)
89 {
90 if (fh->vdev == NULL)
91 return;
92 v4l_disable_media_source(fh->vdev);
93 v4l2_event_unsubscribe_all(fh);
94 mutex_destroy(&fh->subscribe_lock);
95 fh->vdev = NULL;
96 }
97 EXPORT_SYMBOL_GPL(v4l2_fh_exit);
98
v4l2_fh_release(struct file * filp)99 int v4l2_fh_release(struct file *filp)
100 {
101 struct v4l2_fh *fh = filp->private_data;
102
103 if (fh) {
104 v4l2_fh_del(fh);
105 v4l2_fh_exit(fh);
106 kfree(fh);
107 filp->private_data = NULL;
108 }
109 return 0;
110 }
111 EXPORT_SYMBOL_GPL(v4l2_fh_release);
112
v4l2_fh_is_singular(struct v4l2_fh * fh)113 int v4l2_fh_is_singular(struct v4l2_fh *fh)
114 {
115 unsigned long flags;
116 int is_singular;
117
118 if (fh == NULL || fh->vdev == NULL)
119 return 0;
120 spin_lock_irqsave(&fh->vdev->fh_lock, flags);
121 is_singular = list_is_singular(&fh->list);
122 spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
123 return is_singular;
124 }
125 EXPORT_SYMBOL_GPL(v4l2_fh_is_singular);
126