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1/*
2 * v4l2-fh.h
3 *
4 * V4L2 file handle. Store per file handle data for the V4L2
5 * framework. Using file handles is optional for the drivers.
6 *
7 * Copyright (C) 2009--2010 Nokia Corporation.
8 *
9 * Contact: Sakari Ailus <sakari.ailus@iki.fi>
10 *
11 * This program is free software; you can redistribute it and/or
12 * modify it under the terms of the GNU General Public License
13 * version 2 as published by the Free Software Foundation.
14 *
15 * This program is distributed in the hope that it will be useful, but
16 * WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
18 * General Public License for more details.
19 *
20 * You should have received a copy of the GNU General Public License
21 * along with this program; if not, write to the Free Software
22 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
23 * 02110-1301 USA
24 */
25
26#ifndef V4L2_FH_H
27#define V4L2_FH_H
28
29#include <linux/fs.h>
30#include <linux/list.h>
31#include <linux/videodev2.h>
32
33struct video_device;
34struct v4l2_ctrl_handler;
35
36struct v4l2_fh {
37 struct list_head list;
38 struct video_device *vdev;
39 struct v4l2_ctrl_handler *ctrl_handler;
40 enum v4l2_priority prio;
41
42 /* Events */
43 wait_queue_head_t wait;
44 struct list_head subscribed; /* Subscribed events */
45 struct list_head available; /* Dequeueable event */
46 unsigned int navailable;
47 u32 sequence;
48
49#if IS_ENABLED(CONFIG_V4L2_MEM2MEM_DEV)
50 struct v4l2_m2m_ctx *m2m_ctx;
51#endif
52};
53
54/*
55 * Initialise the file handle. Parts of the V4L2 framework using the
56 * file handles should be initialised in this function. Must be called
57 * from driver's v4l2_file_operations->open() handler if the driver
58 * uses v4l2_fh.
59 */
60void v4l2_fh_init(struct v4l2_fh *fh, struct video_device *vdev);
61/*
62 * Add the fh to the list of file handles on a video_device. The file
63 * handle must be initialised first.
64 */
65void v4l2_fh_add(struct v4l2_fh *fh);
66/*
67 * Can be used as the open() op of v4l2_file_operations.
68 * It allocates a v4l2_fh and inits and adds it to the video_device associated
69 * with the file pointer.
70 */
71int v4l2_fh_open(struct file *filp);
72/*
73 * Remove file handle from the list of file handles. Must be called in
74 * v4l2_file_operations->release() handler if the driver uses v4l2_fh.
75 * On error filp->private_data will be NULL, otherwise it will point to
76 * the v4l2_fh struct.
77 */
78void v4l2_fh_del(struct v4l2_fh *fh);
79/*
80 * Release resources related to a file handle. Parts of the V4L2
81 * framework using the v4l2_fh must release their resources here, too.
82 * Must be called in v4l2_file_operations->release() handler if the
83 * driver uses v4l2_fh.
84 */
85void v4l2_fh_exit(struct v4l2_fh *fh);
86/*
87 * Can be used as the release() op of v4l2_file_operations.
88 * It deletes and exits the v4l2_fh associated with the file pointer and
89 * frees it. It will do nothing if filp->private_data (the pointer to the
90 * v4l2_fh struct) is NULL. This function always returns 0.
91 */
92int v4l2_fh_release(struct file *filp);
93/*
94 * Returns 1 if this filehandle is the only filehandle opened for the
95 * associated video_device. If fh is NULL, then it returns 0.
96 */
97int v4l2_fh_is_singular(struct v4l2_fh *fh);
98/*
99 * Helper function with struct file as argument. If filp->private_data is
100 * NULL, then it will return 0.
101 */
102static inline int v4l2_fh_is_singular_file(struct file *filp)
103{
104 return v4l2_fh_is_singular(filp->private_data);
105}
106
107#endif /* V4L2_EVENT_H */
1/*
2 * v4l2-fh.h
3 *
4 * V4L2 file handle. Store per file handle data for the V4L2
5 * framework. Using file handles is optional for the drivers.
6 *
7 * Copyright (C) 2009--2010 Nokia Corporation.
8 *
9 * Contact: Sakari Ailus <sakari.ailus@iki.fi>
10 *
11 * This program is free software; you can redistribute it and/or
12 * modify it under the terms of the GNU General Public License
13 * version 2 as published by the Free Software Foundation.
14 *
15 * This program is distributed in the hope that it will be useful, but
16 * WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
18 * General Public License for more details.
19 */
20
21#ifndef V4L2_FH_H
22#define V4L2_FH_H
23
24#include <linux/fs.h>
25#include <linux/kconfig.h>
26#include <linux/list.h>
27#include <linux/videodev2.h>
28
29struct video_device;
30struct v4l2_ctrl_handler;
31
32/**
33 * struct v4l2_fh - Describes a V4L2 file handler
34 *
35 * @list: list of file handlers
36 * @vdev: pointer to &struct video_device
37 * @ctrl_handler: pointer to &struct v4l2_ctrl_handler
38 * @prio: priority of the file handler, as defined by &enum v4l2_priority
39 *
40 * @wait: event' s wait queue
41 * @subscribed: list of subscribed events
42 * @available: list of events waiting to be dequeued
43 * @navailable: number of available events at @available list
44 * @sequence: event sequence number
45 * @m2m_ctx: pointer to &struct v4l2_m2m_ctx
46 */
47struct v4l2_fh {
48 struct list_head list;
49 struct video_device *vdev;
50 struct v4l2_ctrl_handler *ctrl_handler;
51 enum v4l2_priority prio;
52
53 /* Events */
54 wait_queue_head_t wait;
55 struct list_head subscribed;
56 struct list_head available;
57 unsigned int navailable;
58 u32 sequence;
59
60#if IS_ENABLED(CONFIG_V4L2_MEM2MEM_DEV)
61 struct v4l2_m2m_ctx *m2m_ctx;
62#endif
63};
64
65/**
66 * v4l2_fh_init - Initialise the file handle.
67 *
68 * @fh: pointer to &struct v4l2_fh
69 * @vdev: pointer to &struct video_device
70 *
71 * Parts of the V4L2 framework using the
72 * file handles should be initialised in this function. Must be called
73 * from driver's v4l2_file_operations->open\(\) handler if the driver
74 * uses &struct v4l2_fh.
75 */
76void v4l2_fh_init(struct v4l2_fh *fh, struct video_device *vdev);
77
78/**
79 * v4l2_fh_add - Add the fh to the list of file handles on a video_device.
80 *
81 * @fh: pointer to &struct v4l2_fh
82 *
83 * .. note::
84 * The @fh file handle must be initialised first.
85 */
86void v4l2_fh_add(struct v4l2_fh *fh);
87
88/**
89 * v4l2_fh_open - Ancillary routine that can be used as the open\(\) op
90 * of v4l2_file_operations.
91 *
92 * @filp: pointer to struct file
93 *
94 * It allocates a v4l2_fh and inits and adds it to the &struct video_device
95 * associated with the file pointer.
96 */
97int v4l2_fh_open(struct file *filp);
98
99/**
100 * v4l2_fh_del - Remove file handle from the list of file handles.
101 *
102 * @fh: pointer to &struct v4l2_fh
103 *
104 * On error filp->private_data will be %NULL, otherwise it will point to
105 * the &struct v4l2_fh.
106 *
107 * .. note::
108 * Must be called in v4l2_file_operations->release\(\) handler if the driver
109 * uses &struct v4l2_fh.
110 */
111void v4l2_fh_del(struct v4l2_fh *fh);
112
113/**
114 * v4l2_fh_exit - Release resources related to a file handle.
115 *
116 * @fh: pointer to &struct v4l2_fh
117 *
118 * Parts of the V4L2 framework using the v4l2_fh must release their
119 * resources here, too.
120 *
121 * .. note::
122 * Must be called in v4l2_file_operations->release\(\) handler if the
123 * driver uses &struct v4l2_fh.
124 */
125void v4l2_fh_exit(struct v4l2_fh *fh);
126
127/**
128 * v4l2_fh_release - Ancillary routine that can be used as the release\(\) op
129 * of v4l2_file_operations.
130 *
131 * @filp: pointer to struct file
132 *
133 * It deletes and exits the v4l2_fh associated with the file pointer and
134 * frees it. It will do nothing if filp->private_data (the pointer to the
135 * v4l2_fh struct) is %NULL.
136 *
137 * This function always returns 0.
138 */
139int v4l2_fh_release(struct file *filp);
140
141/**
142 * v4l2_fh_is_singular - Returns 1 if this filehandle is the only filehandle
143 * opened for the associated video_device.
144 *
145 * @fh: pointer to &struct v4l2_fh
146 *
147 * If @fh is NULL, then it returns 0.
148 */
149int v4l2_fh_is_singular(struct v4l2_fh *fh);
150
151/**
152 * v4l2_fh_is_singular_file - Returns 1 if this filehandle is the only
153 * filehandle opened for the associated video_device.
154 *
155 * @filp: pointer to struct file
156 *
157 * This is a helper function variant of v4l2_fh_is_singular() with uses
158 * struct file as argument.
159 *
160 * If filp->private_data is %NULL, then it will return 0.
161 */
162static inline int v4l2_fh_is_singular_file(struct file *filp)
163{
164 return v4l2_fh_is_singular(filp->private_data);
165}
166
167#endif /* V4L2_EVENT_H */