linux/drivers/media/dvb/dvb-core/dvbdev.h
Darron Broad 59b1842da1 V4L/DVB (9227): MFE: Add multi-frontend mutual exclusion
This add frontend R/W mutual exclusion.
Prior to this point in time it was possible to open both
frontends simultaneously which an MFE card cannot support.

In order to stop this, a delayed open is performed which
has the following function:

-  Return EBUSY after a configurable amount of time
   if a frontend is unavailable due to the other being
   in use.

-  Only allow opening of a frontend if the kernel thread
   of the other has stopped.

This solution was chosen to allow switching between
frontends to work as seamlessly as possible. When both
frontends are actually opened simultaneously then one
will only open, but if quick switching is performed
between one of many then the new open will succeed in
a clean fashion rather than interrupting a kernel
thread.

Signed-off-by: Darron Broad <darron@kewl.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2008-10-17 17:24:15 -03:00

144 lines
4 KiB
C

/*
* dvbdev.h
*
* Copyright (C) 2000 Ralph Metzler & Marcus Metzler
* for convergence integrated media GmbH
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Lesser Public License
* as published by the Free Software Foundation; either version 2.1
* of the License, or (at your option) any later version.
*
* 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 Lesser General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
*/
#ifndef _DVBDEV_H_
#define _DVBDEV_H_
#include <linux/types.h>
#include <linux/poll.h>
#include <linux/fs.h>
#include <linux/list.h>
#include <linux/smp_lock.h>
#define DVB_MAJOR 212
#define DVB_MAX_ADAPTERS 8
#define DVB_UNSET (-1)
#define DVB_DEVICE_VIDEO 0
#define DVB_DEVICE_AUDIO 1
#define DVB_DEVICE_SEC 2
#define DVB_DEVICE_FRONTEND 3
#define DVB_DEVICE_DEMUX 4
#define DVB_DEVICE_DVR 5
#define DVB_DEVICE_CA 6
#define DVB_DEVICE_NET 7
#define DVB_DEVICE_OSD 8
#define DVB_DEFINE_MOD_OPT_ADAPTER_NR(adapter_nr) \
static short adapter_nr[] = \
{[0 ... (DVB_MAX_ADAPTERS - 1)] = DVB_UNSET }; \
module_param_array(adapter_nr, short, NULL, 0444); \
MODULE_PARM_DESC(adapter_nr, "DVB adapter numbers")
struct dvb_adapter {
int num;
struct list_head list_head;
struct list_head device_list;
const char *name;
u8 proposed_mac [6];
void* priv;
struct device *device;
struct module *module;
int mfe_shared; /* indicates mutually exclusive frontends */
struct dvb_device *mfe_dvbdev; /* frontend device in use */
struct mutex mfe_lock; /* access lock for thread creation */
};
struct dvb_device {
struct list_head list_head;
struct file_operations *fops;
struct dvb_adapter *adapter;
int type;
u32 id;
/* in theory, 'users' can vanish now,
but I don't want to change too much now... */
int readers;
int writers;
int users;
wait_queue_head_t wait_queue;
/* don't really need those !? -- FIXME: use video_usercopy */
int (*kernel_ioctl)(struct inode *inode, struct file *file,
unsigned int cmd, void *arg);
void *priv;
};
extern int dvb_register_adapter(struct dvb_adapter *adap, const char *name,
struct module *module, struct device *device,
short *adapter_nums);
extern int dvb_unregister_adapter (struct dvb_adapter *adap);
extern int dvb_register_device (struct dvb_adapter *adap,
struct dvb_device **pdvbdev,
const struct dvb_device *template,
void *priv,
int type);
extern void dvb_unregister_device (struct dvb_device *dvbdev);
extern int dvb_generic_open (struct inode *inode, struct file *file);
extern int dvb_generic_release (struct inode *inode, struct file *file);
extern int dvb_generic_ioctl (struct inode *inode, struct file *file,
unsigned int cmd, unsigned long arg);
/* we don't mess with video_usercopy() any more,
we simply define out own dvb_usercopy(), which will hopefully become
generic_usercopy() someday... */
extern int dvb_usercopy(struct inode *inode, struct file *file,
unsigned int cmd, unsigned long arg,
int (*func)(struct inode *inode, struct file *file,
unsigned int cmd, void *arg));
/** generic DVB attach function. */
#ifdef CONFIG_MEDIA_ATTACH
#define dvb_attach(FUNCTION, ARGS...) ({ \
void *__r = NULL; \
typeof(&FUNCTION) __a = symbol_request(FUNCTION); \
if (__a) { \
__r = (void *) __a(ARGS); \
if (__r == NULL) \
symbol_put(FUNCTION); \
} else { \
printk(KERN_ERR "DVB: Unable to find symbol "#FUNCTION"()\n"); \
} \
__r; \
})
#else
#define dvb_attach(FUNCTION, ARGS...) ({ \
FUNCTION(ARGS); \
})
#endif
#endif /* #ifndef _DVBDEV_H_ */