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@maxwell.research.nokia.com>
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 <media/v4l2-dev.h>
28 #include <media/v4l2-fh.h>
29 #include <media/v4l2-event.h>
30 #include <media/v4l2-ioctl.h>
31
v4l2_fh_init(struct v4l2_fh * fh,struct video_device * vdev)32 int v4l2_fh_init(struct v4l2_fh *fh, struct video_device *vdev)
33 {
34 fh->vdev = vdev;
35 INIT_LIST_HEAD(&fh->list);
36 set_bit(V4L2_FL_USES_V4L2_FH, &fh->vdev->flags);
37 fh->prio = V4L2_PRIORITY_UNSET;
38
39 /*
40 * fh->events only needs to be initialized if the driver
41 * supports the VIDIOC_SUBSCRIBE_EVENT ioctl.
42 */
43 if (vdev->ioctl_ops && vdev->ioctl_ops->vidioc_subscribe_event)
44 return v4l2_event_init(fh);
45
46 fh->events = NULL;
47
48 return 0;
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 if (test_bit(V4L2_FL_USE_FH_PRIO, &fh->vdev->flags))
57 v4l2_prio_open(fh->vdev->prio, &fh->prio);
58 spin_lock_irqsave(&fh->vdev->fh_lock, flags);
59 list_add(&fh->list, &fh->vdev->fh_list);
60 spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
61 }
62 EXPORT_SYMBOL_GPL(v4l2_fh_add);
63
v4l2_fh_open(struct file * filp)64 int v4l2_fh_open(struct file *filp)
65 {
66 struct video_device *vdev = video_devdata(filp);
67 struct v4l2_fh *fh = kzalloc(sizeof(*fh), GFP_KERNEL);
68
69 filp->private_data = fh;
70 if (fh == NULL)
71 return -ENOMEM;
72 v4l2_fh_init(fh, vdev);
73 v4l2_fh_add(fh);
74 return 0;
75 }
76 EXPORT_SYMBOL_GPL(v4l2_fh_open);
77
v4l2_fh_del(struct v4l2_fh * fh)78 void v4l2_fh_del(struct v4l2_fh *fh)
79 {
80 unsigned long flags;
81
82 spin_lock_irqsave(&fh->vdev->fh_lock, flags);
83 list_del_init(&fh->list);
84 spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
85 if (test_bit(V4L2_FL_USE_FH_PRIO, &fh->vdev->flags))
86 v4l2_prio_close(fh->vdev->prio, fh->prio);
87 }
88 EXPORT_SYMBOL_GPL(v4l2_fh_del);
89
v4l2_fh_exit(struct v4l2_fh * fh)90 void v4l2_fh_exit(struct v4l2_fh *fh)
91 {
92 if (fh->vdev == NULL)
93 return;
94
95 fh->vdev = NULL;
96
97 v4l2_event_free(fh);
98 }
99 EXPORT_SYMBOL_GPL(v4l2_fh_exit);
100
v4l2_fh_release(struct file * filp)101 int v4l2_fh_release(struct file *filp)
102 {
103 struct v4l2_fh *fh = filp->private_data;
104
105 if (fh) {
106 v4l2_fh_del(fh);
107 v4l2_fh_exit(fh);
108 kfree(fh);
109 }
110 return 0;
111 }
112 EXPORT_SYMBOL_GPL(v4l2_fh_release);
113
v4l2_fh_is_singular(struct v4l2_fh * fh)114 int v4l2_fh_is_singular(struct v4l2_fh *fh)
115 {
116 unsigned long flags;
117 int is_singular;
118
119 if (fh == NULL || fh->vdev == NULL)
120 return 0;
121 spin_lock_irqsave(&fh->vdev->fh_lock, flags);
122 is_singular = list_is_singular(&fh->list);
123 spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
124 return is_singular;
125 }
126 EXPORT_SYMBOL_GPL(v4l2_fh_is_singular);
127