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 fh->prio = V4L2_PRIORITY_UNSET;
41 init_waitqueue_head(&fh->wait);
42 INIT_LIST_HEAD(&fh->available);
43 INIT_LIST_HEAD(&fh->subscribed);
44 fh->sequence = -1;
45 }
46 EXPORT_SYMBOL_GPL(v4l2_fh_init);
47
v4l2_fh_add(struct v4l2_fh * fh)48 void v4l2_fh_add(struct v4l2_fh *fh)
49 {
50 unsigned long flags;
51
52 if (test_bit(V4L2_FL_USE_FH_PRIO, &fh->vdev->flags))
53 v4l2_prio_open(fh->vdev->prio, &fh->prio);
54 spin_lock_irqsave(&fh->vdev->fh_lock, flags);
55 list_add(&fh->list, &fh->vdev->fh_list);
56 spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
57 }
58 EXPORT_SYMBOL_GPL(v4l2_fh_add);
59
v4l2_fh_open(struct file * filp)60 int v4l2_fh_open(struct file *filp)
61 {
62 struct video_device *vdev = video_devdata(filp);
63 struct v4l2_fh *fh = kzalloc(sizeof(*fh), GFP_KERNEL);
64
65 filp->private_data = fh;
66 if (fh == NULL)
67 return -ENOMEM;
68 v4l2_fh_init(fh, vdev);
69 v4l2_fh_add(fh);
70 return 0;
71 }
72 EXPORT_SYMBOL_GPL(v4l2_fh_open);
73
v4l2_fh_del(struct v4l2_fh * fh)74 void v4l2_fh_del(struct v4l2_fh *fh)
75 {
76 unsigned long flags;
77
78 spin_lock_irqsave(&fh->vdev->fh_lock, flags);
79 list_del_init(&fh->list);
80 spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
81 if (test_bit(V4L2_FL_USE_FH_PRIO, &fh->vdev->flags))
82 v4l2_prio_close(fh->vdev->prio, fh->prio);
83 }
84 EXPORT_SYMBOL_GPL(v4l2_fh_del);
85
v4l2_fh_exit(struct v4l2_fh * fh)86 void v4l2_fh_exit(struct v4l2_fh *fh)
87 {
88 if (fh->vdev == NULL)
89 return;
90 v4l2_event_unsubscribe_all(fh);
91 fh->vdev = NULL;
92 }
93 EXPORT_SYMBOL_GPL(v4l2_fh_exit);
94
v4l2_fh_release(struct file * filp)95 int v4l2_fh_release(struct file *filp)
96 {
97 struct v4l2_fh *fh = filp->private_data;
98
99 if (fh) {
100 v4l2_fh_del(fh);
101 v4l2_fh_exit(fh);
102 kfree(fh);
103 }
104 return 0;
105 }
106 EXPORT_SYMBOL_GPL(v4l2_fh_release);
107
v4l2_fh_is_singular(struct v4l2_fh * fh)108 int v4l2_fh_is_singular(struct v4l2_fh *fh)
109 {
110 unsigned long flags;
111 int is_singular;
112
113 if (fh == NULL || fh->vdev == NULL)
114 return 0;
115 spin_lock_irqsave(&fh->vdev->fh_lock, flags);
116 is_singular = list_is_singular(&fh->list);
117 spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
118 return is_singular;
119 }
120 EXPORT_SYMBOL_GPL(v4l2_fh_is_singular);
121