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 * You should have received a copy of the GNU General Public License
20 * along with this program; if not, write to the Free Software
21 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
22 * 02110-1301 USA
23 */
24
25 #include <linux/bitops.h>
26 #include <linux/slab.h>
27 #include <linux/export.h>
28 #include <media/v4l2-dev.h>
29 #include <media/v4l2-fh.h>
30 #include <media/v4l2-event.h>
31 #include <media/v4l2-ioctl.h>
32
v4l2_fh_init(struct v4l2_fh * fh,struct video_device * vdev)33 void v4l2_fh_init(struct v4l2_fh *fh, struct video_device *vdev)
34 {
35 fh->vdev = vdev;
36 /* Inherit from video_device. May be overridden by the driver. */
37 fh->ctrl_handler = vdev->ctrl_handler;
38 INIT_LIST_HEAD(&fh->list);
39 set_bit(V4L2_FL_USES_V4L2_FH, &fh->vdev->flags);
40 /*
41 * determine_valid_ioctls() does not know if struct v4l2_fh
42 * is used by this driver, but here we do. So enable the
43 * prio ioctls here.
44 */
45 set_bit(_IOC_NR(VIDIOC_G_PRIORITY), vdev->valid_ioctls);
46 set_bit(_IOC_NR(VIDIOC_S_PRIORITY), vdev->valid_ioctls);
47 fh->prio = V4L2_PRIORITY_UNSET;
48 init_waitqueue_head(&fh->wait);
49 INIT_LIST_HEAD(&fh->available);
50 INIT_LIST_HEAD(&fh->subscribed);
51 fh->sequence = -1;
52 mutex_init(&fh->subscribe_lock);
53 }
54 EXPORT_SYMBOL_GPL(v4l2_fh_init);
55
v4l2_fh_add(struct v4l2_fh * fh)56 void v4l2_fh_add(struct v4l2_fh *fh)
57 {
58 unsigned long flags;
59
60 v4l2_prio_open(fh->vdev->prio, &fh->prio);
61 spin_lock_irqsave(&fh->vdev->fh_lock, flags);
62 list_add(&fh->list, &fh->vdev->fh_list);
63 spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
64 }
65 EXPORT_SYMBOL_GPL(v4l2_fh_add);
66
v4l2_fh_open(struct file * filp)67 int v4l2_fh_open(struct file *filp)
68 {
69 struct video_device *vdev = video_devdata(filp);
70 struct v4l2_fh *fh = kzalloc(sizeof(*fh), GFP_KERNEL);
71
72 filp->private_data = fh;
73 if (fh == NULL)
74 return -ENOMEM;
75 v4l2_fh_init(fh, vdev);
76 v4l2_fh_add(fh);
77 return 0;
78 }
79 EXPORT_SYMBOL_GPL(v4l2_fh_open);
80
v4l2_fh_del(struct v4l2_fh * fh)81 void v4l2_fh_del(struct v4l2_fh *fh)
82 {
83 unsigned long flags;
84
85 spin_lock_irqsave(&fh->vdev->fh_lock, flags);
86 list_del_init(&fh->list);
87 spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
88 v4l2_prio_close(fh->vdev->prio, fh->prio);
89 }
90 EXPORT_SYMBOL_GPL(v4l2_fh_del);
91
v4l2_fh_exit(struct v4l2_fh * fh)92 void v4l2_fh_exit(struct v4l2_fh *fh)
93 {
94 if (fh->vdev == NULL)
95 return;
96 v4l2_event_unsubscribe_all(fh);
97 mutex_destroy(&fh->subscribe_lock);
98 fh->vdev = NULL;
99 }
100 EXPORT_SYMBOL_GPL(v4l2_fh_exit);
101
v4l2_fh_release(struct file * filp)102 int v4l2_fh_release(struct file *filp)
103 {
104 struct v4l2_fh *fh = filp->private_data;
105
106 if (fh) {
107 v4l2_fh_del(fh);
108 v4l2_fh_exit(fh);
109 kfree(fh);
110 filp->private_data = NULL;
111 }
112 return 0;
113 }
114 EXPORT_SYMBOL_GPL(v4l2_fh_release);
115
v4l2_fh_is_singular(struct v4l2_fh * fh)116 int v4l2_fh_is_singular(struct v4l2_fh *fh)
117 {
118 unsigned long flags;
119 int is_singular;
120
121 if (fh == NULL || fh->vdev == NULL)
122 return 0;
123 spin_lock_irqsave(&fh->vdev->fh_lock, flags);
124 is_singular = list_is_singular(&fh->list);
125 spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
126 return is_singular;
127 }
128 EXPORT_SYMBOL_GPL(v4l2_fh_is_singular);
129