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/* SPDX-License-Identifier: GPL-2.0-only */
  2/*
  3 * v4l2-fh.h
  4 *
  5 * V4L2 file handle. Store per file handle data for the V4L2
  6 * framework. Using file handles is optional for the drivers.
  7 *
  8 * Copyright (C) 2009--2010 Nokia Corporation.
  9 *
 10 * Contact: Sakari Ailus <sakari.ailus@iki.fi>
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 11 */
 12
 13#ifndef V4L2_FH_H
 14#define V4L2_FH_H
 15
 16#include <linux/fs.h>
 17#include <linux/kconfig.h>
 18#include <linux/list.h>
 19#include <linux/videodev2.h>
 20
 21struct video_device;
 22struct v4l2_ctrl_handler;
 23
 24/**
 25 * struct v4l2_fh - Describes a V4L2 file handler
 26 *
 27 * @list: list of file handlers
 28 * @vdev: pointer to &struct video_device
 29 * @ctrl_handler: pointer to &struct v4l2_ctrl_handler
 30 * @prio: priority of the file handler, as defined by &enum v4l2_priority
 31 *
 32 * @wait: event' s wait queue
 33 * @subscribe_lock: serialise changes to the subscribed list; guarantee that
 34 *		    the add and del event callbacks are orderly called
 35 * @subscribed: list of subscribed events
 36 * @available: list of events waiting to be dequeued
 37 * @navailable: number of available events at @available list
 38 * @sequence: event sequence number
 39 *
 40 * @m2m_ctx: pointer to &struct v4l2_m2m_ctx
 41 */
 42struct v4l2_fh {
 43	struct list_head	list;
 44	struct video_device	*vdev;
 45	struct v4l2_ctrl_handler *ctrl_handler;
 46	enum v4l2_priority	prio;
 47
 48	/* Events */
 49	wait_queue_head_t	wait;
 50	struct mutex		subscribe_lock;
 51	struct list_head	subscribed;
 52	struct list_head	available;
 53	unsigned int		navailable;
 54	u32			sequence;
 55
 56#if IS_ENABLED(CONFIG_V4L2_MEM2MEM_DEV)
 57	struct v4l2_m2m_ctx	*m2m_ctx;
 58#endif
 59};
 60
 61/**
 62 * v4l2_fh_init - Initialise the file handle.
 63 *
 64 * @fh: pointer to &struct v4l2_fh
 65 * @vdev: pointer to &struct video_device
 66 *
 67 * Parts of the V4L2 framework using the
 68 * file handles should be initialised in this function. Must be called
 69 * from driver's v4l2_file_operations->open\(\) handler if the driver
 70 * uses &struct v4l2_fh.
 71 */
 72void v4l2_fh_init(struct v4l2_fh *fh, struct video_device *vdev);
 73
 74/**
 75 * v4l2_fh_add - Add the fh to the list of file handles on a video_device.
 76 *
 77 * @fh: pointer to &struct v4l2_fh
 78 *
 79 * .. note::
 80 *    The @fh file handle must be initialised first.
 81 */
 82void v4l2_fh_add(struct v4l2_fh *fh);
 83
 84/**
 85 * v4l2_fh_open - Ancillary routine that can be used as the open\(\) op
 86 *	of v4l2_file_operations.
 87 *
 88 * @filp: pointer to struct file
 89 *
 90 * It allocates a v4l2_fh and inits and adds it to the &struct video_device
 91 * associated with the file pointer.
 92 */
 93int v4l2_fh_open(struct file *filp);
 94
 95/**
 96 * v4l2_fh_del - Remove file handle from the list of file handles.
 97 *
 98 * @fh: pointer to &struct v4l2_fh
 99 *
100 * On error filp->private_data will be %NULL, otherwise it will point to
101 * the &struct v4l2_fh.
102 *
103 * .. note::
104 *    Must be called in v4l2_file_operations->release\(\) handler if the driver
105 *    uses &struct v4l2_fh.
106 */
107void v4l2_fh_del(struct v4l2_fh *fh);
108
109/**
110 * v4l2_fh_exit - Release resources related to a file handle.
111 *
112 * @fh: pointer to &struct v4l2_fh
113 *
114 * Parts of the V4L2 framework using the v4l2_fh must release their
115 * resources here, too.
116 *
117 * .. note::
118 *    Must be called in v4l2_file_operations->release\(\) handler if the
119 *    driver uses &struct v4l2_fh.
120 */
121void v4l2_fh_exit(struct v4l2_fh *fh);
122
123/**
124 * v4l2_fh_release - Ancillary routine that can be used as the release\(\) op
125 *	of v4l2_file_operations.
126 *
127 * @filp: pointer to struct file
128 *
129 * It deletes and exits the v4l2_fh associated with the file pointer and
130 * frees it. It will do nothing if filp->private_data (the pointer to the
131 * v4l2_fh struct) is %NULL.
132 *
133 * This function always returns 0.
134 */
135int v4l2_fh_release(struct file *filp);
136
137/**
138 * v4l2_fh_is_singular - Returns 1 if this filehandle is the only filehandle
139 *	 opened for the associated video_device.
140 *
141 * @fh: pointer to &struct v4l2_fh
142 *
143 * If @fh is NULL, then it returns 0.
144 */
145int v4l2_fh_is_singular(struct v4l2_fh *fh);
146
147/**
148 * v4l2_fh_is_singular_file - Returns 1 if this filehandle is the only
149 *	filehandle opened for the associated video_device.
150 *
151 * @filp: pointer to struct file
152 *
153 * This is a helper function variant of v4l2_fh_is_singular() with uses
154 * struct file as argument.
155 *
156 * If filp->private_data is %NULL, then it will return 0.
157 */
158static inline int v4l2_fh_is_singular_file(struct file *filp)
159{
160	return v4l2_fh_is_singular(filp->private_data);
161}
162
163#endif /* V4L2_EVENT_H */