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Commit 9b5d0f1e authored by Sakari Ailus's avatar Sakari Ailus Committed by Mauro Carvalho Chehab
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V4L/DVB (5862): V4L: Add internal ioctl-like interface. 



This patch adds an internal ioctl-like interface which can be used in
situations where a single Video4Linux device is implemented by multiple
device drivers. One master device controls one or more slave devices.
The slaves provide Video4Linux ioctl-like interface for the use of the
master.

Only a handful of ioctls are implemented at the moment. More can (and
should) be added as more functionality is required.

Signed-off-by: default avatarSakari Ailus <sakari.ailus@nokia.com>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@infradead.org>
parent bbf25010

drivers/media/video/Makefile

+2 −1
Original line number Diff line number Diff line
@@ -11,7 +11,8 @@ tuner-$(CONFIG_TUNER_TEA5761) += tea5761.o 


msp3400-objs	:=	msp3400-driver.o msp3400-kthreads.o



obj-$(CONFIG_VIDEO_DEV) += videodev.o v4l2-common.o compat_ioctl32.o

obj-$(CONFIG_VIDEO_DEV) += videodev.o v4l2-common.o compat_ioctl32.o \

			   v4l2-int-device.o



ifeq ($(CONFIG_VIDEO_V4L1_COMPAT),y)

  obj-$(CONFIG_VIDEO_DEV) += v4l1-compat.o

drivers/media/video/v4l2-int-device.c

0 → 100644
+154 −0
Original line number Diff line number Diff line 
/*

 * drivers/media/video/v4l2-int-device.c

 *

 * V4L2 internal ioctl interface.

 *

 * Copyright (C) 2007 Nokia Corporation.

 *

 * Contact: Sakari Ailus <sakari.ailus@nokia.com>

 *

 * 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

 */



#include <linux/kernel.h>

#include <linux/list.h>

#include <linux/sort.h>

#include <linux/string.h>



#include <media/v4l2-int-device.h>



static DEFINE_MUTEX(mutex);

static LIST_HEAD(int_list);



static void v4l2_int_device_try_attach_all(void)

{

	struct list_head *head_master;



	list_for_each(head_master, &int_list) {

		struct list_head *head_slave;

		struct v4l2_int_device *m =

			list_entry(head_master, struct v4l2_int_device, head);



		if (m->type != v4l2_int_type_master)

			continue;



		list_for_each(head_slave, &int_list) {

			struct v4l2_int_device *s =

				list_entry(head_slave,

					   struct v4l2_int_device, head);



			if (s->type != v4l2_int_type_slave)

				continue;



			/* Slave is connected? */

			if (s->u.slave->master)

				continue;



			/* Slave wants to attach to master? */

			if (s->u.slave->attach_to[0] != 0

			    && strncmp(m->name, s->u.slave->attach_to,

				       V4L2NAMESIZE))

				continue;



			if (!try_module_get(m->module))

				continue;



			if (m->u.master->attach(m, s)) {

				module_put(m->module);

				continue;

			}



			s->u.slave->master = m;

		}

	}

}



static int ioctl_sort_cmp(const void *a, const void *b)

{

	const struct v4l2_int_ioctl_desc *d1 = a, *d2 = b;



	if (d1->num > d2->num)

		return 1;



	if (d1->num < d2->num)

		return -1;



	return 0;

}



int v4l2_int_device_register(struct v4l2_int_device *d)

{

	if (d->type == v4l2_int_type_slave)

		sort(d->u.slave->ioctls, d->u.slave->num_ioctls,

		     sizeof(struct v4l2_int_ioctl_desc),

		     &ioctl_sort_cmp, NULL);

	mutex_lock(&mutex);

	list_add(&d->head, &int_list);

	v4l2_int_device_try_attach_all();

	mutex_unlock(&mutex);



	return 0;

}



void v4l2_int_device_unregister(struct v4l2_int_device *d)

{

	mutex_lock(&mutex);

	list_del(&d->head);

	if (d->type == v4l2_int_type_slave

	    && d->u.slave->master != NULL) {

		d->u.slave->master->u.master->detach(d);

		module_put(d->u.slave->master->module);

		d->u.slave->master = NULL;

	}

	mutex_unlock(&mutex);

}



static int no_such_ioctl(struct v4l2_int_device *d)

{

	return -EINVAL;

}



/* Adapted from search_extable in extable.c. */

static v4l2_int_ioctl_func *find_ioctl(struct v4l2_int_slave *slave, int cmd)

{

	const struct v4l2_int_ioctl_desc *first = slave->ioctls;

	const struct v4l2_int_ioctl_desc *last =

		first + slave->num_ioctls - 1;



	while (first <= last) {

		const struct v4l2_int_ioctl_desc *mid;



		mid = (last - first) / 2 + first;



		if (mid->num < cmd)

			first = mid + 1;

		else if (mid->num > cmd)

			last = mid - 1;

		else

			return mid->func;

	}



	return &no_such_ioctl;

}



int v4l2_int_ioctl_0(struct v4l2_int_device *d, int cmd)

{

	return ((v4l2_int_ioctl_func_0 *)find_ioctl(d->u.slave, cmd))(d);

}



int v4l2_int_ioctl_1(struct v4l2_int_device *d, int cmd, void *arg)

{

	return ((v4l2_int_ioctl_func_1 *)find_ioctl(d->u.slave, cmd))(d, arg);

}

include/media/v4l2-int-device.h

0 → 100644
+210 −0
Original line number Diff line number Diff line 
/*

 * include/media/v4l2-int-device.h

 *

 * V4L2 internal ioctl interface.

 *

 * Copyright (C) 2007 Nokia Corporation.

 *

 * Contact: Sakari Ailus <sakari.ailus@nokia.com>

 *

 * 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_INT_DEVICE_H

#define V4L2_INT_DEVICE_H



#include <linux/module.h>

#include <media/v4l2-common.h>



#define V4L2NAMESIZE 32



enum v4l2_int_type {

	v4l2_int_type_master = 1,

	v4l2_int_type_slave

};



enum v4l2_int_ioctl_num {

	/*

	 *

	 * "Proper" V4L ioctls, as in struct video_device.

	 *

	 */

	vidioc_int_enum_fmt_cap_num = 1,

	vidioc_int_g_fmt_cap_num,

	vidioc_int_s_fmt_cap_num,

	vidioc_int_try_fmt_cap_num,

	vidioc_int_queryctrl_num,

	vidioc_int_g_ctrl_num,

	vidioc_int_s_ctrl_num,

	vidioc_int_g_parm_num,

	vidioc_int_s_parm_num,



	/*

	 *

	 * Strictly internal ioctls.

	 *

	 */

	/* Initialise the device when slave attaches to the master. */

	vidioc_int_dev_init_num = 1000,

	/* Delinitialise the device at slave detach. */

	vidioc_int_dev_exit_num,

	/* Set device power state: 0 is off, non-zero is on. */

	vidioc_int_s_power_num,

	/* Get parallel interface clock speed for current settings. */

	vidioc_int_g_ext_clk_num,

	/*

	 * Tell what the parallel interface clock speed actually is.

	 */

	vidioc_int_s_ext_clk_num,

	/* Does the slave need to be reset after VIDIOC_DQBUF? */

	vidioc_int_g_needs_reset_num,



	/*

	 *

	 * VIDIOC_INT_* ioctls.

	 *

	 */

	/* VIDIOC_INT_RESET */

	vidioc_int_reset_num,

	/* VIDIOC_INT_INIT */

	vidioc_int_init_num,

	/* VIDIOC_INT_G_CHIP_IDENT */

	vidioc_int_g_chip_ident_num,



	/*

	 *

	 * Start of private ioctls.

	 *

	 */

	vidioc_int_priv_start_num = 2000,

};



struct v4l2_int_device;



struct v4l2_int_master {

	int (*attach)(struct v4l2_int_device *master,

		      struct v4l2_int_device *slave);

	void (*detach)(struct v4l2_int_device *master);

};



typedef int (v4l2_int_ioctl_func)(struct v4l2_int_device *);

typedef int (v4l2_int_ioctl_func_0)(struct v4l2_int_device *);

typedef int (v4l2_int_ioctl_func_1)(struct v4l2_int_device *, void *);



struct v4l2_int_ioctl_desc {

	int num;

	v4l2_int_ioctl_func *func;

};



struct v4l2_int_slave {

	/* Don't touch master. */

	struct v4l2_int_device *master;



	char attach_to[V4L2NAMESIZE];



	int num_ioctls;

	struct v4l2_int_ioctl_desc *ioctls;

};



struct v4l2_int_device {

	/* Don't touch head. */

	struct list_head head;



	struct module *module;



	char name[V4L2NAMESIZE];



	enum v4l2_int_type type;

	union {

		struct v4l2_int_master *master;

		struct v4l2_int_slave *slave;

	} u;



	void *priv;

};



int v4l2_int_device_register(struct v4l2_int_device *d);

void v4l2_int_device_unregister(struct v4l2_int_device *d);



int v4l2_int_ioctl_0(struct v4l2_int_device *d, int cmd);

int v4l2_int_ioctl_1(struct v4l2_int_device *d, int cmd, void *arg);



/*

 *

 * IOCTL wrapper functions for better type checking.

 *

 */



#define V4L2_INT_WRAPPER_0(name)					\

	static inline int vidioc_int_##name(struct v4l2_int_device *d)	\

	{								\

		return v4l2_int_ioctl_0(d, vidioc_int_##name##_num);	\

	}								\

									\

	static inline struct v4l2_int_ioctl_desc			\

	vidioc_int_##name##_cb(int (*func)				\

			       (struct v4l2_int_device *))		\

	{								\

		struct v4l2_int_ioctl_desc desc;			\

									\

		desc.num = vidioc_int_##name##_num;			\

		desc.func = (v4l2_int_ioctl_func *)func;		\

									\

		return desc;						\

	}



#define V4L2_INT_WRAPPER_1(name, arg_type, asterisk)			\

	static inline int vidioc_int_##name(struct v4l2_int_device *d,	\

					    arg_type asterisk arg)	\

	{								\

		return v4l2_int_ioctl_1(d, vidioc_int_##name##_num,	\

					(void *)arg);			\

	}								\

									\

	static inline struct v4l2_int_ioctl_desc			\

	vidioc_int_##name##_cb(int (*func)				\

			       (struct v4l2_int_device *,		\

				arg_type asterisk))			\

	{								\

		struct v4l2_int_ioctl_desc desc;			\

									\

		desc.num = vidioc_int_##name##_num;			\

		desc.func = (v4l2_int_ioctl_func *)func;		\

									\

		return desc;						\

	}



V4L2_INT_WRAPPER_1(enum_fmt_cap, struct v4l2_fmtdesc, *);

V4L2_INT_WRAPPER_1(g_fmt_cap, struct v4l2_format, *);

V4L2_INT_WRAPPER_1(s_fmt_cap, struct v4l2_format, *);

V4L2_INT_WRAPPER_1(try_fmt_cap, struct v4l2_format, *);

V4L2_INT_WRAPPER_1(queryctrl, struct v4l2_queryctrl, *);

V4L2_INT_WRAPPER_1(g_ctrl, struct v4l2_control, *);

V4L2_INT_WRAPPER_1(s_ctrl, struct v4l2_control, *);

V4L2_INT_WRAPPER_1(g_parm, struct v4l2_streamparm, *);

V4L2_INT_WRAPPER_1(s_parm, struct v4l2_streamparm, *);



V4L2_INT_WRAPPER_0(dev_init);

V4L2_INT_WRAPPER_0(dev_exit);

V4L2_INT_WRAPPER_1(s_power, int, );

V4L2_INT_WRAPPER_1(s_ext_clk, u32, );

V4L2_INT_WRAPPER_1(g_ext_clk, u32, *);

V4L2_INT_WRAPPER_1(g_needs_reset, void, *);



V4L2_INT_WRAPPER_0(reset);

V4L2_INT_WRAPPER_0(init);

V4L2_INT_WRAPPER_1(g_chip_ident, int, *);



#endif