linux/include/media/v4l2-fh.h
Sylwester Nawrocki 8e6e8f93f7 [media] V4L: Add mem2mem ioctl and file operation helpers
This patch adds ioctl helpers to the V4L2 mem-to-mem API, so we can avoid
several ioctl handlers in the mem-to-mem video node drivers that are simply
a pass-through to the v4l2_m2m_* calls. These helpers will only be useful
for drivers that use same mutex for both OUTPUT and CAPTURE queue, which
is the case for all currently in tree v4l2 m2m drivers. In order to use
the helpers the drivers are required to use struct v4l2_fh.

Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2013-12-04 15:34:24 -02:00

108 lines
3.4 KiB
C

/*
* v4l2-fh.h
*
* V4L2 file handle. Store per file handle data for the V4L2
* framework. Using file handles is optional for the drivers.
*
* Copyright (C) 2009--2010 Nokia Corporation.
*
* Contact: Sakari Ailus <sakari.ailus@iki.fi>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* version 2 as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA
*/
#ifndef V4L2_FH_H
#define V4L2_FH_H
#include <linux/fs.h>
#include <linux/list.h>
#include <linux/videodev2.h>
struct video_device;
struct v4l2_ctrl_handler;
struct v4l2_fh {
struct list_head list;
struct video_device *vdev;
struct v4l2_ctrl_handler *ctrl_handler;
enum v4l2_priority prio;
/* Events */
wait_queue_head_t wait;
struct list_head subscribed; /* Subscribed events */
struct list_head available; /* Dequeueable event */
unsigned int navailable;
u32 sequence;
#if IS_ENABLED(CONFIG_V4L2_MEM2MEM_DEV)
struct v4l2_m2m_ctx *m2m_ctx;
#endif
};
/*
* Initialise the file handle. Parts of the V4L2 framework using the
* file handles should be initialised in this function. Must be called
* from driver's v4l2_file_operations->open() handler if the driver
* uses v4l2_fh.
*/
void v4l2_fh_init(struct v4l2_fh *fh, struct video_device *vdev);
/*
* Add the fh to the list of file handles on a video_device. The file
* handle must be initialised first.
*/
void v4l2_fh_add(struct v4l2_fh *fh);
/*
* Can be used as the open() op of v4l2_file_operations.
* It allocates a v4l2_fh and inits and adds it to the video_device associated
* with the file pointer.
*/
int v4l2_fh_open(struct file *filp);
/*
* Remove file handle from the list of file handles. Must be called in
* v4l2_file_operations->release() handler if the driver uses v4l2_fh.
* On error filp->private_data will be NULL, otherwise it will point to
* the v4l2_fh struct.
*/
void v4l2_fh_del(struct v4l2_fh *fh);
/*
* Release resources related to a file handle. Parts of the V4L2
* framework using the v4l2_fh must release their resources here, too.
* Must be called in v4l2_file_operations->release() handler if the
* driver uses v4l2_fh.
*/
void v4l2_fh_exit(struct v4l2_fh *fh);
/*
* Can be used as the release() op of v4l2_file_operations.
* It deletes and exits the v4l2_fh associated with the file pointer and
* frees it. It will do nothing if filp->private_data (the pointer to the
* v4l2_fh struct) is NULL. This function always returns 0.
*/
int v4l2_fh_release(struct file *filp);
/*
* Returns 1 if this filehandle is the only filehandle opened for the
* associated video_device. If fh is NULL, then it returns 0.
*/
int v4l2_fh_is_singular(struct v4l2_fh *fh);
/*
* Helper function with struct file as argument. If filp->private_data is
* NULL, then it will return 0.
*/
static inline int v4l2_fh_is_singular_file(struct file *filp)
{
return v4l2_fh_is_singular(filp->private_data);
}
#endif /* V4L2_EVENT_H */