[mirror_ubuntu-bionic-kernel.git] / drivers / media / video / v4l2-dev.c

/*
 * Video capture interface for Linux version 2
 *
 *	A generic video device interface for the LINUX operating system
 *	using a set of device structures/vectors for low level operations.
 *
 *	This program is free software; you can redistribute it and/or
 *	modify it under the terms of the GNU General Public License
 *	as published by the Free Software Foundation; either version
 *	2 of the License, or (at your option) any later version.
 *
 * Authors:	Alan Cox, <alan@lxorguk.ukuu.org.uk> (version 1)
 *              Mauro Carvalho Chehab <mchehab@infradead.org> (version 2)
 *
 * Fixes:	20000516  Claudio Matsuoka <claudio@conectiva.com>
 *		- Added procfs support
 */

#include <linux/module.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/kmod.h>
#include <linux/slab.h>
#include <linux/smp_lock.h>
#include <asm/uaccess.h>
#include <asm/system.h>

#include <media/v4l2-common.h>
#include <media/v4l2-device.h>
#include <media/v4l2-ioctl.h>

#define VIDEO_NUM_DEVICES	256
#define VIDEO_NAME              "video4linux"

/*
 *	sysfs stuff
 */

static ssize_t show_index(struct device *cd,
			 struct device_attribute *attr, char *buf)
{
	struct video_device *vdev = to_video_device(cd);

	return sprintf(buf, "%i\n", vdev->index);
}

static ssize_t show_name(struct device *cd,
			 struct device_attribute *attr, char *buf)
{
	struct video_device *vdev = to_video_device(cd);

	return sprintf(buf, "%.*s\n", (int)sizeof(vdev->name), vdev->name);
}

static struct device_attribute video_device_attrs[] = {
	__ATTR(name, S_IRUGO, show_name, NULL),
	__ATTR(index, S_IRUGO, show_index, NULL),
	__ATTR_NULL
};

/*
 *	Active devices
 */
static struct video_device *video_device[VIDEO_NUM_DEVICES];
static DEFINE_MUTEX(videodev_lock);
static DECLARE_BITMAP(video_nums[VFL_TYPE_MAX], VIDEO_NUM_DEVICES);

struct video_device *video_device_alloc(void)
{
	return kzalloc(sizeof(struct video_device), GFP_KERNEL);
}
EXPORT_SYMBOL(video_device_alloc);

void video_device_release(struct video_device *vdev)
{
	kfree(vdev);
}
EXPORT_SYMBOL(video_device_release);

void video_device_release_empty(struct video_device *vdev)
{
	/* Do nothing */
	/* Only valid when the video_device struct is a static. */
}
EXPORT_SYMBOL(video_device_release_empty);

static inline void video_get(struct video_device *vdev)
{
	get_device(&vdev->dev);
}

static inline void video_put(struct video_device *vdev)
{
	put_device(&vdev->dev);
}

/* Called when the last user of the video device exits. */
static void v4l2_device_release(struct device *cd)
{
	struct video_device *vdev = to_video_device(cd);

	mutex_lock(&videodev_lock);
	if (video_device[vdev->minor] != vdev) {
		mutex_unlock(&videodev_lock);
		/* should not happen */
		WARN_ON(1);
		return;
	}

	/* Free up this device for reuse */
	video_device[vdev->minor] = NULL;

	/* Delete the cdev on this minor as well */
	cdev_del(vdev->cdev);
	/* Just in case some driver tries to access this from
	   the release() callback. */
	vdev->cdev = NULL;

	/* Mark minor as free */
	clear_bit(vdev->num, video_nums[vdev->vfl_type]);

	mutex_unlock(&videodev_lock);

	/* Release video_device and perform other
	   cleanups as needed. */
	vdev->release(vdev);
}

static struct class video_class = {
	.name = VIDEO_NAME,
	.dev_attrs = video_device_attrs,
};

struct video_device *video_devdata(struct file *file)
{
	return video_device[iminor(file->f_path.dentry->d_inode)];
}
EXPORT_SYMBOL(video_devdata);

static ssize_t v4l2_read(struct file *filp, char __user *buf,
		size_t sz, loff_t *off)
{
	struct video_device *vdev = video_devdata(filp);

	if (!vdev->fops->read)
		return -EINVAL;
	if (video_is_unregistered(vdev))
		return -EIO;
	return vdev->fops->read(filp, buf, sz, off);
}

static ssize_t v4l2_write(struct file *filp, const char __user *buf,
		size_t sz, loff_t *off)
{
	struct video_device *vdev = video_devdata(filp);

	if (!vdev->fops->write)
		return -EINVAL;
	if (video_is_unregistered(vdev))
		return -EIO;
	return vdev->fops->write(filp, buf, sz, off);
}

static unsigned int v4l2_poll(struct file *filp, struct poll_table_struct *poll)
{
	struct video_device *vdev = video_devdata(filp);

	if (!vdev->fops->poll || video_is_unregistered(vdev))
		return DEFAULT_POLLMASK;
	return vdev->fops->poll(filp, poll);
}

static int v4l2_ioctl(struct inode *inode, struct file *filp,
		unsigned int cmd, unsigned long arg)
{
	struct video_device *vdev = video_devdata(filp);

	if (!vdev->fops->ioctl)
		return -ENOTTY;
	/* Allow ioctl to continue even if the device was unregistered.
	   Things like dequeueing buffers might still be useful. */
	return vdev->fops->ioctl(filp, cmd, arg);
}

static long v4l2_unlocked_ioctl(struct file *filp,
		unsigned int cmd, unsigned long arg)
{
	struct video_device *vdev = video_devdata(filp);

	if (!vdev->fops->unlocked_ioctl)
		return -ENOTTY;
	/* Allow ioctl to continue even if the device was unregistered.
	   Things like dequeueing buffers might still be useful. */
	return vdev->fops->unlocked_ioctl(filp, cmd, arg);
}

#ifdef CONFIG_MMU
#define v4l2_get_unmapped_area NULL
#else
static unsigned long v4l2_get_unmapped_area(struct file *filp,
		unsigned long addr, unsigned long len, unsigned long pgoff,
		unsigned long flags)
{
	struct video_device *vdev = video_devdata(filp);

	if (!vdev->fops->get_unmapped_area)
		return -ENOSYS;
	if (video_is_unregistered(vdev))
		return -ENODEV;
	return vdev->fops->get_unmapped_area(filp, addr, len, pgoff, flags);
}
#endif

static int v4l2_mmap(struct file *filp, struct vm_area_struct *vm)
{
	struct video_device *vdev = video_devdata(filp);

	if (!vdev->fops->mmap ||
	    video_is_unregistered(vdev))
		return -ENODEV;
	return vdev->fops->mmap(filp, vm);
}

/* Override for the open function */
static int v4l2_open(struct inode *inode, struct file *filp)
{
	struct video_device *vdev;
	int ret;

	/* Check if the video device is available */
	mutex_lock(&videodev_lock);
	vdev = video_devdata(filp);
	/* return ENODEV if the video device has been removed
	   already or if it is not registered anymore. */
	if (vdev == NULL || video_is_unregistered(vdev)) {
		mutex_unlock(&videodev_lock);
		return -ENODEV;
	}
	/* and increase the device refcount */
	video_get(vdev);
	mutex_unlock(&videodev_lock);
	ret = vdev->fops->open(filp);
	/* decrease the refcount in case of an error */
	if (ret)
		video_put(vdev);
	return ret;
}

/* Override for the release function */
static int v4l2_release(struct inode *inode, struct file *filp)
{
	struct video_device *vdev = video_devdata(filp);
	int ret = vdev->fops->release(filp);

	/* decrease the refcount unconditionally since the release()
	   return value is ignored. */
	video_put(vdev);
	return ret;
}

static const struct file_operations v4l2_unlocked_fops = {
	.owner = THIS_MODULE,
	.read = v4l2_read,
	.write = v4l2_write,
	.open = v4l2_open,
	.get_unmapped_area = v4l2_get_unmapped_area,
	.mmap = v4l2_mmap,
	.unlocked_ioctl = v4l2_unlocked_ioctl,
#ifdef CONFIG_COMPAT
	.compat_ioctl = v4l2_compat_ioctl32,
#endif
	.release = v4l2_release,
	.poll = v4l2_poll,
	.llseek = no_llseek,
};

static const struct file_operations v4l2_fops = {
	.owner = THIS_MODULE,
	.read = v4l2_read,
	.write = v4l2_write,
	.open = v4l2_open,
	.get_unmapped_area = v4l2_get_unmapped_area,
	.mmap = v4l2_mmap,
	.ioctl = v4l2_ioctl,
#ifdef CONFIG_COMPAT
	.compat_ioctl = v4l2_compat_ioctl32,
#endif
	.release = v4l2_release,
	.poll = v4l2_poll,
	.llseek = no_llseek,
};

/**
 * get_index - assign stream number based on parent device
 * @vdev: video_device to assign index number to, vdev->parent should be assigned
 * @num:  -1 if auto assign, requested number otherwise
 *
 * Note that when this is called the new device has not yet been registered
 * in the video_device array.
 *
 * Returns -ENFILE if num is already in use, a free index number if
 * successful.
 */
static int get_index(struct video_device *vdev, int num)
{
	/* This can be static since this function is called with the global
	   videodev_lock held. */
	static DECLARE_BITMAP(used, VIDEO_NUM_DEVICES);
	int i;

	if (num >= VIDEO_NUM_DEVICES) {
		printk(KERN_ERR "videodev: %s num is too large\n", __func__);
		return -EINVAL;
	}

	/* Some drivers do not set the parent. In that case always return
	   num or 0. */
	if (vdev->parent == NULL)
		return num >= 0 ? num : 0;

	bitmap_zero(used, VIDEO_NUM_DEVICES);

	for (i = 0; i < VIDEO_NUM_DEVICES; i++) {
		if (video_device[i] != NULL &&
		    video_device[i]->parent == vdev->parent) {
			set_bit(video_device[i]->index, used);
		}
	}

	if (num >= 0) {
		if (test_bit(num, used))
			return -ENFILE;
		return num;
	}

	i = find_first_zero_bit(used, VIDEO_NUM_DEVICES);
	return i == VIDEO_NUM_DEVICES ? -ENFILE : i;
}

int video_register_device(struct video_device *vdev, int type, int nr)
{
	return video_register_device_index(vdev, type, nr, -1);
}
EXPORT_SYMBOL(video_register_device);

/**
 *	video_register_device_index - register video4linux devices
 *	@vdev: video device structure we want to register
 *	@type: type of device to register
 *	@nr:   which device number (0 == /dev/video0, 1 == /dev/video1, ...
 *             -1 == first free)
 *	@index: stream number based on parent device;
 *		-1 if auto assign, requested number otherwise
 *
 *	The registration code assigns minor numbers based on the type
 *	requested. -ENFILE is returned in all the device slots for this
 *	category are full. If not then the minor field is set and the
 *	driver initialize function is called (if non %NULL).
 *
 *	Zero is returned on success.
 *
 *	Valid types are
 *
 *	%VFL_TYPE_GRABBER - A frame grabber
 *
 *	%VFL_TYPE_VTX - A teletext device
 *
 *	%VFL_TYPE_VBI - Vertical blank data (undecoded)
 *
 *	%VFL_TYPE_RADIO - A radio card
 */
int video_register_device_index(struct video_device *vdev, int type, int nr,
					int index)
{
	int i = 0;
	int ret;
	int minor_offset = 0;
	int minor_cnt = VIDEO_NUM_DEVICES;
	const char *name_base;
	void *priv = video_get_drvdata(vdev);

	/* A minor value of -1 marks this video device as never
	   having been registered */
	vdev->minor = -1;

	/* the release callback MUST be present */
	WARN_ON(!vdev->release);
	if (!vdev->release)
		return -EINVAL;

	/* Part 1: check device type */
	switch (type) {
	case VFL_TYPE_GRABBER:
		name_base = "video";
		break;
	case VFL_TYPE_VTX:
		name_base = "vtx";
		break;
	case VFL_TYPE_VBI:
		name_base = "vbi";
		break;
	case VFL_TYPE_RADIO:
		name_base = "radio";
		break;
	default:
		printk(KERN_ERR "%s called with unknown type: %d\n",
		       __func__, type);
		return -EINVAL;
	}

	vdev->vfl_type = type;
	vdev->cdev = NULL;
	if (vdev->v4l2_dev && vdev->v4l2_dev->dev)
		vdev->parent = vdev->v4l2_dev->dev;

	/* Part 2: find a free minor, kernel number and device index. */
#ifdef CONFIG_VIDEO_FIXED_MINOR_RANGES
	/* Keep the ranges for the first four types for historical
	 * reasons.
	 * Newer devices (not yet in place) should use the range
	 * of 128-191 and just pick the first free minor there
	 * (new style). */
	switch (type) {
	case VFL_TYPE_GRABBER:
		minor_offset = 0;
		minor_cnt = 64;
		break;
	case VFL_TYPE_RADIO:
		minor_offset = 64;
		minor_cnt = 64;
		break;
	case VFL_TYPE_VTX:
		minor_offset = 192;
		minor_cnt = 32;
		break;
	case VFL_TYPE_VBI:
		minor_offset = 224;
		minor_cnt = 32;
		break;
	default:
		minor_offset = 128;
		minor_cnt = 64;
		break;
	}
#endif

	/* Pick a minor number */
	mutex_lock(&videodev_lock);
	nr = find_next_zero_bit(video_nums[type], minor_cnt, nr == -1 ? 0 : nr);
	if (nr == minor_cnt)
		nr = find_first_zero_bit(video_nums[type], minor_cnt);
	if (nr == minor_cnt) {
		printk(KERN_ERR "could not get a free kernel number\n");
		mutex_unlock(&videodev_lock);
		return -ENFILE;
	}
#ifdef CONFIG_VIDEO_FIXED_MINOR_RANGES
	/* 1-on-1 mapping of kernel number to minor number */
	i = nr;
#else
	/* The kernel number and minor numbers are independent */
	for (i = 0; i < VIDEO_NUM_DEVICES; i++)
		if (video_device[i] == NULL)
			break;
	if (i == VIDEO_NUM_DEVICES) {
		mutex_unlock(&videodev_lock);
		printk(KERN_ERR "could not get a free minor\n");
		return -ENFILE;
	}
#endif
	vdev->minor = i + minor_offset;
	vdev->num = nr;
	set_bit(nr, video_nums[type]);
	/* Should not happen since we thought this minor was free */
	WARN_ON(video_device[vdev->minor] != NULL);
	ret = vdev->index = get_index(vdev, index);
	mutex_unlock(&videodev_lock);

	if (ret < 0) {
		printk(KERN_ERR "%s: get_index failed\n", __func__);
		goto cleanup;
	}

	/* Part 3: Initialize the character device */
	vdev->cdev = cdev_alloc();
	if (vdev->cdev == NULL) {
		ret = -ENOMEM;
		goto cleanup;
	}
	if (vdev->fops->unlocked_ioctl)
		vdev->cdev->ops = &v4l2_unlocked_fops;
	else
		vdev->cdev->ops = &v4l2_fops;
	vdev->cdev->owner = vdev->fops->owner;
	ret = cdev_add(vdev->cdev, MKDEV(VIDEO_MAJOR, vdev->minor), 1);
	if (ret < 0) {
		printk(KERN_ERR "%s: cdev_add failed\n", __func__);
		kfree(vdev->cdev);
		vdev->cdev = NULL;
		goto cleanup;
	}

	/* Part 4: register the device with sysfs */
	memset(&vdev->dev, 0, sizeof(vdev->dev));
	/* The memset above cleared the device's drvdata, so
	   put back the copy we made earlier. */
	video_set_drvdata(vdev, priv);
	vdev->dev.class = &video_class;
	vdev->dev.devt = MKDEV(VIDEO_MAJOR, vdev->minor);
	if (vdev->parent)
		vdev->dev.parent = vdev->parent;
	dev_set_name(&vdev->dev, "%s%d", name_base, nr);
	ret = device_register(&vdev->dev);
	if (ret < 0) {
		printk(KERN_ERR "%s: device_register failed\n", __func__);
		goto cleanup;
	}
	/* Register the release callback that will be called when the last
	   reference to the device goes away. */
	vdev->dev.release = v4l2_device_release;

	/* Part 5: Activate this minor. The char device can now be used. */
	mutex_lock(&videodev_lock);
	video_device[vdev->minor] = vdev;
	mutex_unlock(&videodev_lock);
	return 0;

cleanup:
	mutex_lock(&videodev_lock);
	if (vdev->cdev)
		cdev_del(vdev->cdev);
	clear_bit(vdev->num, video_nums[type]);
	mutex_unlock(&videodev_lock);
	/* Mark this video device as never having been registered. */
	vdev->minor = -1;
	return ret;
}
EXPORT_SYMBOL(video_register_device_index);

/**
 *	video_unregister_device - unregister a video4linux device
 *	@vdev: the device to unregister
 *
 *	This unregisters the passed device. Future open calls will
 *	be met with errors.
 */
void video_unregister_device(struct video_device *vdev)
{
	/* Check if vdev was ever registered at all */
	if (!vdev || vdev->minor < 0)
		return;

	mutex_lock(&videodev_lock);
	set_bit(V4L2_FL_UNREGISTERED, &vdev->flags);
	mutex_unlock(&videodev_lock);
	device_unregister(&vdev->dev);
}
EXPORT_SYMBOL(video_unregister_device);

/*
 *	Initialise video for linux
 */
static int __init videodev_init(void)
{
	dev_t dev = MKDEV(VIDEO_MAJOR, 0);
	int ret;

	printk(KERN_INFO "Linux video capture interface: v2.00\n");
	ret = register_chrdev_region(dev, VIDEO_NUM_DEVICES, VIDEO_NAME);
	if (ret < 0) {
		printk(KERN_WARNING "videodev: unable to get major %d\n",
				VIDEO_MAJOR);
		return ret;
	}

	ret = class_register(&video_class);
	if (ret < 0) {
		unregister_chrdev_region(dev, VIDEO_NUM_DEVICES);
		printk(KERN_WARNING "video_dev: class_register failed\n");
		return -EIO;
	}

	return 0;
}

static void __exit videodev_exit(void)
{
	dev_t dev = MKDEV(VIDEO_MAJOR, 0);

	class_unregister(&video_class);
	unregister_chrdev_region(dev, VIDEO_NUM_DEVICES);
}

module_init(videodev_init)
module_exit(videodev_exit)

MODULE_AUTHOR("Alan Cox, Mauro Carvalho Chehab <mchehab@infradead.org>");
MODULE_DESCRIPTION("Device registrar for Video4Linux drivers v2");
MODULE_LICENSE("GPL");
MODULE_ALIAS_CHARDEV_MAJOR(VIDEO_MAJOR);


/*
 * Local variables:
 * c-basic-offset: 8
 * End:
 */
Commit	Line	Data
27a5e6d3 HV	1	/*
	2	* Video capture interface for Linux version 2
	3	*
	4	* A generic video device interface for the LINUX operating system
	5	* using a set of device structures/vectors for low level operations.
	6	*
	7	* This program is free software; you can redistribute it and/or
	8	* modify it under the terms of the GNU General Public License
	9	* as published by the Free Software Foundation; either version
	10	* 2 of the License, or (at your option) any later version.
	11	*
d9b01449	12	* Authors: Alan Cox, <alan@lxorguk.ukuu.org.uk> (version 1)
27a5e6d3 HV	13	* Mauro Carvalho Chehab <mchehab@infradead.org> (version 2)
	14	*
	15	* Fixes: 20000516 Claudio Matsuoka <claudio@conectiva.com>
	16	* - Added procfs support
	17	*/
	18
	19	#include <linux/module.h>
	20	#include <linux/types.h>
	21	#include <linux/kernel.h>
	22	#include <linux/mm.h>
	23	#include <linux/string.h>
	24	#include <linux/errno.h>
	25	#include <linux/init.h>
	26	#include <linux/kmod.h>
	27	#include <linux/slab.h>
	28	#include <linux/smp_lock.h>
	29	#include <asm/uaccess.h>
	30	#include <asm/system.h>
	31
	32	#include <media/v4l2-common.h>
9bea3514	33	#include <media/v4l2-device.h>
bec43661	34	#include <media/v4l2-ioctl.h>
27a5e6d3 HV	35
	36	#define VIDEO_NUM_DEVICES 256
	37	#define VIDEO_NAME "video4linux"
	38
	39	/*
	40	* sysfs stuff
	41	*/
	42
	43	static ssize_t show_index(struct device *cd,
	44	struct device_attribute attr, char buf)
	45	{
dc93a70c	46	struct video_device *vdev = to_video_device(cd);
bfa8a273	47
dc93a70c	48	return sprintf(buf, "%i\n", vdev->index);
27a5e6d3 HV	49	}
	50
	51	static ssize_t show_name(struct device *cd,
	52	struct device_attribute attr, char buf)
	53	{
dc93a70c	54	struct video_device *vdev = to_video_device(cd);
bfa8a273	55
dc93a70c	56	return sprintf(buf, "%.*s\n", (int)sizeof(vdev->name), vdev->name);
27a5e6d3 HV	57	}
	58
	59	static struct device_attribute video_device_attrs[] = {
	60	__ATTR(name, S_IRUGO, show_name, NULL),
	61	__ATTR(index, S_IRUGO, show_index, NULL),
	62	__ATTR_NULL
	63	};
	64
7f8ecfab HV	65	/*
	66	* Active devices
	67	*/
	68	static struct video_device *video_device[VIDEO_NUM_DEVICES];
	69	static DEFINE_MUTEX(videodev_lock);
dd89601d	70	static DECLARE_BITMAP(video_nums[VFL_TYPE_MAX], VIDEO_NUM_DEVICES);
7f8ecfab	71
27a5e6d3 HV	72	struct video_device *video_device_alloc(void)
27a5e6d3 HV	73	{
bfa8a273	74	return kzalloc(sizeof(struct video_device), GFP_KERNEL);
27a5e6d3 HV	75	}
	76	EXPORT_SYMBOL(video_device_alloc);
	77
dc93a70c	78	void video_device_release(struct video_device *vdev)
27a5e6d3	79	{
dc93a70c	80	kfree(vdev);
27a5e6d3 HV	81	}
	82	EXPORT_SYMBOL(video_device_release);
	83
dc93a70c	84	void video_device_release_empty(struct video_device *vdev)
f9e86b5e HV	85	{
	86	/* Do nothing */
	87	/* Only valid when the video_device struct is a static. */
	88	}
	89	EXPORT_SYMBOL(video_device_release_empty);
	90
dc93a70c	91	static inline void video_get(struct video_device *vdev)
7f8ecfab	92	{
dc93a70c HV	93	get_device(&vdev->dev);
	94	}
	95
	96	static inline void video_put(struct video_device *vdev)
	97	{
	98	put_device(&vdev->dev);
	99	}
	100
	101	/* Called when the last user of the video device exits. */
	102	static void v4l2_device_release(struct device *cd)
	103	{
	104	struct video_device *vdev = to_video_device(cd);
7f8ecfab HV	105
7f8ecfab HV	106	mutex_lock(&videodev_lock);
dc93a70c	107	if (video_device[vdev->minor] != vdev) {
6ea9a182	108	mutex_unlock(&videodev_lock);
dc93a70c HV	109	/* should not happen */
dc93a70c HV	110	WARN_ON(1);
6ea9a182 HV	111	return;
6ea9a182 HV	112	}
7f8ecfab HV	113
7f8ecfab HV	114	/* Free up this device for reuse */
dc93a70c	115	video_device[vdev->minor] = NULL;
7f8ecfab	116
dc93a70c HV	117	/* Delete the cdev on this minor as well */
	118	cdev_del(vdev->cdev);
	119	/* Just in case some driver tries to access this from
	120	the release() callback. */
	121	vdev->cdev = NULL;
7f8ecfab	122
dc93a70c HV	123	/* Mark minor as free */
dc93a70c HV	124	clear_bit(vdev->num, video_nums[vdev->vfl_type]);
7f8ecfab	125
dc93a70c	126	mutex_unlock(&videodev_lock);
27a5e6d3	127
dc93a70c HV	128	/* Release video_device and perform other
	129	cleanups as needed. */
	130	vdev->release(vdev);
27a5e6d3 HV	131	}
	132
	133	static struct class video_class = {
	134	.name = VIDEO_NAME,
	135	.dev_attrs = video_device_attrs,
27a5e6d3 HV	136	};
27a5e6d3 HV	137
27a5e6d3 HV	138	struct video_device video_devdata(struct file file)
	139	{
	140	return video_device[iminor(file->f_path.dentry->d_inode)];
	141	}
	142	EXPORT_SYMBOL(video_devdata);
	143
dc93a70c HV	144	static ssize_t v4l2_read(struct file filp, char __user buf,
	145	size_t sz, loff_t *off)
	146	{
	147	struct video_device *vdev = video_devdata(filp);
	148
	149	if (!vdev->fops->read)
	150	return -EINVAL;
	151	if (video_is_unregistered(vdev))
	152	return -EIO;
	153	return vdev->fops->read(filp, buf, sz, off);
	154	}
	155
	156	static ssize_t v4l2_write(struct file filp, const char __user buf,
	157	size_t sz, loff_t *off)
	158	{
	159	struct video_device *vdev = video_devdata(filp);
	160
	161	if (!vdev->fops->write)
	162	return -EINVAL;
	163	if (video_is_unregistered(vdev))
	164	return -EIO;
	165	return vdev->fops->write(filp, buf, sz, off);
	166	}
	167
	168	static unsigned int v4l2_poll(struct file filp, struct poll_table_struct poll)
	169	{
	170	struct video_device *vdev = video_devdata(filp);
	171
	172	if (!vdev->fops->poll \|\| video_is_unregistered(vdev))
	173	return DEFAULT_POLLMASK;
	174	return vdev->fops->poll(filp, poll);
	175	}
	176
	177	static int v4l2_ioctl(struct inode inode, struct file filp,
	178	unsigned int cmd, unsigned long arg)
	179	{
	180	struct video_device *vdev = video_devdata(filp);
	181
	182	if (!vdev->fops->ioctl)
	183	return -ENOTTY;
	184	/* Allow ioctl to continue even if the device was unregistered.
	185	Things like dequeueing buffers might still be useful. */
bec43661	186	return vdev->fops->ioctl(filp, cmd, arg);
dc93a70c HV	187	}
	188
	189	static long v4l2_unlocked_ioctl(struct file *filp,
	190	unsigned int cmd, unsigned long arg)
	191	{
	192	struct video_device *vdev = video_devdata(filp);
	193
	194	if (!vdev->fops->unlocked_ioctl)
	195	return -ENOTTY;
	196	/* Allow ioctl to continue even if the device was unregistered.
	197	Things like dequeueing buffers might still be useful. */
	198	return vdev->fops->unlocked_ioctl(filp, cmd, arg);
	199	}
	200
c01f1a5a DG	201	#ifdef CONFIG_MMU
	202	#define v4l2_get_unmapped_area NULL
	203	#else
	204	static unsigned long v4l2_get_unmapped_area(struct file *filp,
	205	unsigned long addr, unsigned long len, unsigned long pgoff,
	206	unsigned long flags)
	207	{
	208	struct video_device *vdev = video_devdata(filp);
	209
	210	if (!vdev->fops->get_unmapped_area)
	211	return -ENOSYS;
	212	if (video_is_unregistered(vdev))
	213	return -ENODEV;
	214	return vdev->fops->get_unmapped_area(filp, addr, len, pgoff, flags);
	215	}
	216	#endif
	217
dc93a70c HV	218	static int v4l2_mmap(struct file filp, struct vm_area_struct vm)
	219	{
	220	struct video_device *vdev = video_devdata(filp);
	221
	222	if (!vdev->fops->mmap \|\|
	223	video_is_unregistered(vdev))
	224	return -ENODEV;
	225	return vdev->fops->mmap(filp, vm);
	226	}
	227
	228	/* Override for the open function */
	229	static int v4l2_open(struct inode inode, struct file filp)
	230	{
	231	struct video_device *vdev;
	232	int ret;
	233
	234	/* Check if the video device is available */
	235	mutex_lock(&videodev_lock);
	236	vdev = video_devdata(filp);
	237	/* return ENODEV if the video device has been removed
	238	already or if it is not registered anymore. */
	239	if (vdev == NULL \|\| video_is_unregistered(vdev)) {
	240	mutex_unlock(&videodev_lock);
	241	return -ENODEV;
	242	}
	243	/* and increase the device refcount */
	244	video_get(vdev);
	245	mutex_unlock(&videodev_lock);
bec43661	246	ret = vdev->fops->open(filp);
dc93a70c HV	247	/* decrease the refcount in case of an error */
	248	if (ret)
	249	video_put(vdev);
	250	return ret;
	251	}
	252
	253	/* Override for the release function */
	254	static int v4l2_release(struct inode inode, struct file filp)
	255	{
	256	struct video_device *vdev = video_devdata(filp);
bec43661	257	int ret = vdev->fops->release(filp);
dc93a70c HV	258
	259	/* decrease the refcount unconditionally since the release()
	260	return value is ignored. */
	261	video_put(vdev);
	262	return ret;
	263	}
	264
	265	static const struct file_operations v4l2_unlocked_fops = {
	266	.owner = THIS_MODULE,
	267	.read = v4l2_read,
	268	.write = v4l2_write,
	269	.open = v4l2_open,
c01f1a5a	270	.get_unmapped_area = v4l2_get_unmapped_area,
dc93a70c HV	271	.mmap = v4l2_mmap,
	272	.unlocked_ioctl = v4l2_unlocked_ioctl,
	273	#ifdef CONFIG_COMPAT
9bb7cde7	274	.compat_ioctl = v4l2_compat_ioctl32,
dc93a70c HV	275	#endif
	276	.release = v4l2_release,
	277	.poll = v4l2_poll,
	278	.llseek = no_llseek,
	279	};
	280
	281	static const struct file_operations v4l2_fops = {
	282	.owner = THIS_MODULE,
	283	.read = v4l2_read,
	284	.write = v4l2_write,
	285	.open = v4l2_open,
c01f1a5a	286	.get_unmapped_area = v4l2_get_unmapped_area,
dc93a70c HV	287	.mmap = v4l2_mmap,
	288	.ioctl = v4l2_ioctl,
	289	#ifdef CONFIG_COMPAT
9bb7cde7	290	.compat_ioctl = v4l2_compat_ioctl32,
dc93a70c HV	291	#endif
	292	.release = v4l2_release,
	293	.poll = v4l2_poll,
	294	.llseek = no_llseek,
	295	};
	296
27a5e6d3 HV	297	/**
27a5e6d3 HV	298	* get_index - assign stream number based on parent device
dc93a70c HV	299	* @vdev: video_device to assign index number to, vdev->parent should be assigned
dc93a70c HV	300	* @num: -1 if auto assign, requested number otherwise
27a5e6d3	301	*
dc93a70c HV	302	* Note that when this is called the new device has not yet been registered
dc93a70c HV	303	* in the video_device array.
27a5e6d3	304	*
dc93a70c	305	* Returns -ENFILE if num is already in use, a free index number if
27a5e6d3 HV	306	* successful.
	307	*/
	308	static int get_index(struct video_device *vdev, int num)
	309	{
775a05dd HV	310	/* This can be static since this function is called with the global
	311	videodev_lock held. */
	312	static DECLARE_BITMAP(used, VIDEO_NUM_DEVICES);
27a5e6d3 HV	313	int i;
27a5e6d3 HV	314
775a05dd	315	if (num >= VIDEO_NUM_DEVICES) {
27a5e6d3 HV	316	printk(KERN_ERR "videodev: %s num is too large\n", __func__);
	317	return -EINVAL;
	318	}
	319
775a05dd HV	320	/* Some drivers do not set the parent. In that case always return
775a05dd HV	321	num or 0. */
806e5b7c	322	if (vdev->parent == NULL)
775a05dd HV	323	return num >= 0 ? num : 0;
	324
	325	bitmap_zero(used, VIDEO_NUM_DEVICES);
806e5b7c	326
27a5e6d3 HV	327	for (i = 0; i < VIDEO_NUM_DEVICES; i++) {
27a5e6d3 HV	328	if (video_device[i] != NULL &&
5e85e732	329	video_device[i]->parent == vdev->parent) {
775a05dd	330	set_bit(video_device[i]->index, used);
27a5e6d3 HV	331	}
	332	}
	333
	334	if (num >= 0) {
775a05dd	335	if (test_bit(num, used))
27a5e6d3 HV	336	return -ENFILE;
	337	return num;
	338	}
	339
775a05dd HV	340	i = find_first_zero_bit(used, VIDEO_NUM_DEVICES);
775a05dd HV	341	return i == VIDEO_NUM_DEVICES ? -ENFILE : i;
27a5e6d3 HV	342	}
27a5e6d3 HV	343
dc93a70c	344	int video_register_device(struct video_device *vdev, int type, int nr)
27a5e6d3	345	{
dc93a70c	346	return video_register_device_index(vdev, type, nr, -1);
27a5e6d3 HV	347	}
	348	EXPORT_SYMBOL(video_register_device);
	349
	350	/**
edc9189c	351	* video_register_device_index - register video4linux devices
dc93a70c	352	* @vdev: video device structure we want to register
27a5e6d3 HV	353	* @type: type of device to register
	354	* @nr: which device number (0 == /dev/video0, 1 == /dev/video1, ...
	355	* -1 == first free)
edc9189c RD	356	* @index: stream number based on parent device;
edc9189c RD	357	* -1 if auto assign, requested number otherwise
27a5e6d3 HV	358	*
	359	* The registration code assigns minor numbers based on the type
	360	* requested. -ENFILE is returned in all the device slots for this
	361	* category are full. If not then the minor field is set and the
	362	* driver initialize function is called (if non %NULL).
	363	*
	364	* Zero is returned on success.
	365	*
	366	* Valid types are
	367	*
	368	* %VFL_TYPE_GRABBER - A frame grabber
	369	*
	370	* %VFL_TYPE_VTX - A teletext device
	371	*
	372	* %VFL_TYPE_VBI - Vertical blank data (undecoded)
	373	*
	374	* %VFL_TYPE_RADIO - A radio card
	375	*/
dc93a70c	376	int video_register_device_index(struct video_device *vdev, int type, int nr,
27a5e6d3 HV	377	int index)
	378	{
	379	int i = 0;
27a5e6d3	380	int ret;
dd89601d HV	381	int minor_offset = 0;
	382	int minor_cnt = VIDEO_NUM_DEVICES;
	383	const char *name_base;
dc93a70c	384	void *priv = video_get_drvdata(vdev);
27a5e6d3	385
dc93a70c HV	386	/* A minor value of -1 marks this video device as never
dc93a70c HV	387	having been registered */
428c8d19	388	vdev->minor = -1;
ee7aa9f8	389
dc93a70c	390	/* the release callback MUST be present */
428c8d19 TP	391	WARN_ON(!vdev->release);
428c8d19 TP	392	if (!vdev->release)
f3b9f50e HK	393	return -EINVAL;
f3b9f50e HK	394
dc93a70c	395	/* Part 1: check device type */
27a5e6d3 HV	396	switch (type) {
27a5e6d3 HV	397	case VFL_TYPE_GRABBER:
27a5e6d3 HV	398	name_base = "video";
	399	break;
	400	case VFL_TYPE_VTX:
27a5e6d3 HV	401	name_base = "vtx";
	402	break;
	403	case VFL_TYPE_VBI:
27a5e6d3 HV	404	name_base = "vbi";
	405	break;
	406	case VFL_TYPE_RADIO:
27a5e6d3 HV	407	name_base = "radio";
	408	break;
	409	default:
	410	printk(KERN_ERR "%s called with unknown type: %d\n",
	411	__func__, type);
46f2c21c	412	return -EINVAL;
27a5e6d3 HV	413	}
27a5e6d3 HV	414
dc93a70c HV	415	vdev->vfl_type = type;
dc93a70c HV	416	vdev->cdev = NULL;
00575961	417	if (vdev->v4l2_dev && vdev->v4l2_dev->dev)
9bea3514	418	vdev->parent = vdev->v4l2_dev->dev;
dd89601d	419
dc93a70c	420	/* Part 2: find a free minor, kernel number and device index. */
dd89601d HV	421	#ifdef CONFIG_VIDEO_FIXED_MINOR_RANGES
	422	/* Keep the ranges for the first four types for historical
	423	* reasons.
	424	* Newer devices (not yet in place) should use the range
	425	* of 128-191 and just pick the first free minor there
	426	* (new style). */
	427	switch (type) {
	428	case VFL_TYPE_GRABBER:
	429	minor_offset = 0;
	430	minor_cnt = 64;
	431	break;
	432	case VFL_TYPE_RADIO:
	433	minor_offset = 64;
	434	minor_cnt = 64;
	435	break;
	436	case VFL_TYPE_VTX:
	437	minor_offset = 192;
	438	minor_cnt = 32;
	439	break;
	440	case VFL_TYPE_VBI:
	441	minor_offset = 224;
	442	minor_cnt = 32;
	443	break;
	444	default:
	445	minor_offset = 128;
	446	minor_cnt = 64;
	447	break;
	448	}
	449	#endif
	450
dc93a70c	451	/* Pick a minor number */
27a5e6d3	452	mutex_lock(&videodev_lock);
dd89601d HV	453	nr = find_next_zero_bit(video_nums[type], minor_cnt, nr == -1 ? 0 : nr);
	454	if (nr == minor_cnt)
	455	nr = find_first_zero_bit(video_nums[type], minor_cnt);
	456	if (nr == minor_cnt) {
	457	printk(KERN_ERR "could not get a free kernel number\n");
	458	mutex_unlock(&videodev_lock);
	459	return -ENFILE;
27a5e6d3	460	}
dd89601d HV	461	#ifdef CONFIG_VIDEO_FIXED_MINOR_RANGES
	462	/* 1-on-1 mapping of kernel number to minor number */
	463	i = nr;
	464	#else
	465	/* The kernel number and minor numbers are independent */
	466	for (i = 0; i < VIDEO_NUM_DEVICES; i++)
	467	if (video_device[i] == NULL)
	468	break;
	469	if (i == VIDEO_NUM_DEVICES) {
	470	mutex_unlock(&videodev_lock);
	471	printk(KERN_ERR "could not get a free minor\n");
	472	return -ENFILE;
	473	}
	474	#endif
dc93a70c HV	475	vdev->minor = i + minor_offset;
dc93a70c HV	476	vdev->num = nr;
dd89601d	477	set_bit(nr, video_nums[type]);
dc93a70c HV	478	/* Should not happen since we thought this minor was free */
	479	WARN_ON(video_device[vdev->minor] != NULL);
	480	ret = vdev->index = get_index(vdev, index);
27a5e6d3 HV	481	mutex_unlock(&videodev_lock);
	482
	483	if (ret < 0) {
	484	printk(KERN_ERR "%s: get_index failed\n", __func__);
dc93a70c	485	goto cleanup;
27a5e6d3 HV	486	}
27a5e6d3 HV	487
dc93a70c HV	488	/* Part 3: Initialize the character device */
	489	vdev->cdev = cdev_alloc();
	490	if (vdev->cdev == NULL) {
	491	ret = -ENOMEM;
	492	goto cleanup;
	493	}
	494	if (vdev->fops->unlocked_ioctl)
	495	vdev->cdev->ops = &v4l2_unlocked_fops;
	496	else
	497	vdev->cdev->ops = &v4l2_fops;
	498	vdev->cdev->owner = vdev->fops->owner;
	499	ret = cdev_add(vdev->cdev, MKDEV(VIDEO_MAJOR, vdev->minor), 1);
7f8ecfab HV	500	if (ret < 0) {
7f8ecfab HV	501	printk(KERN_ERR "%s: cdev_add failed\n", __func__);
dc93a70c HV	502	kfree(vdev->cdev);
	503	vdev->cdev = NULL;
	504	goto cleanup;
7f8ecfab	505	}
dc93a70c HV	506
	507	/* Part 4: register the device with sysfs */
	508	memset(&vdev->dev, 0, sizeof(vdev->dev));
9d95af9d HV	509	/* The memset above cleared the device's drvdata, so
9d95af9d HV	510	put back the copy we made earlier. */
dc93a70c HV	511	video_set_drvdata(vdev, priv);
	512	vdev->dev.class = &video_class;
	513	vdev->dev.devt = MKDEV(VIDEO_MAJOR, vdev->minor);
	514	if (vdev->parent)
	515	vdev->dev.parent = vdev->parent;
	516	dev_set_name(&vdev->dev, "%s%d", name_base, nr);
	517	ret = device_register(&vdev->dev);
27a5e6d3 HV	518	if (ret < 0) {
27a5e6d3 HV	519	printk(KERN_ERR "%s: device_register failed\n", __func__);
dc93a70c	520	goto cleanup;
27a5e6d3	521	}
dc93a70c HV	522	/* Register the release callback that will be called when the last
	523	reference to the device goes away. */
	524	vdev->dev.release = v4l2_device_release;
27a5e6d3	525
dc93a70c HV	526	/* Part 5: Activate this minor. The char device can now be used. */
	527	mutex_lock(&videodev_lock);
	528	video_device[vdev->minor] = vdev;
	529	mutex_unlock(&videodev_lock);
	530	return 0;
7f8ecfab	531
dc93a70c	532	cleanup:
27a5e6d3	533	mutex_lock(&videodev_lock);
dc93a70c HV	534	if (vdev->cdev)
	535	cdev_del(vdev->cdev);
	536	clear_bit(vdev->num, video_nums[type]);
27a5e6d3	537	mutex_unlock(&videodev_lock);
dc93a70c HV	538	/* Mark this video device as never having been registered. */
dc93a70c HV	539	vdev->minor = -1;
27a5e6d3 HV	540	return ret;
	541	}
	542	EXPORT_SYMBOL(video_register_device_index);
	543
	544	/**
	545	* video_unregister_device - unregister a video4linux device
dc93a70c	546	* @vdev: the device to unregister
27a5e6d3	547	*
dc93a70c HV	548	* This unregisters the passed device. Future open calls will
dc93a70c HV	549	* be met with errors.
27a5e6d3	550	*/
dc93a70c	551	void video_unregister_device(struct video_device *vdev)
27a5e6d3	552	{
dc93a70c HV	553	/* Check if vdev was ever registered at all */
	554	if (!vdev \|\| vdev->minor < 0)
	555	return;
	556
	557	mutex_lock(&videodev_lock);
	558	set_bit(V4L2_FL_UNREGISTERED, &vdev->flags);
	559	mutex_unlock(&videodev_lock);
	560	device_unregister(&vdev->dev);
27a5e6d3 HV	561	}
	562	EXPORT_SYMBOL(video_unregister_device);
	563
27a5e6d3 HV	564	/*
	565	* Initialise video for linux
	566	*/
27a5e6d3 HV	567	static int __init videodev_init(void)
27a5e6d3 HV	568	{
7f8ecfab	569	dev_t dev = MKDEV(VIDEO_MAJOR, 0);
27a5e6d3 HV	570	int ret;
	571
	572	printk(KERN_INFO "Linux video capture interface: v2.00\n");
7f8ecfab HV	573	ret = register_chrdev_region(dev, VIDEO_NUM_DEVICES, VIDEO_NAME);
	574	if (ret < 0) {
	575	printk(KERN_WARNING "videodev: unable to get major %d\n",
	576	VIDEO_MAJOR);
	577	return ret;
27a5e6d3 HV	578	}
	579
	580	ret = class_register(&video_class);
	581	if (ret < 0) {
7f8ecfab	582	unregister_chrdev_region(dev, VIDEO_NUM_DEVICES);
27a5e6d3 HV	583	printk(KERN_WARNING "video_dev: class_register failed\n");
	584	return -EIO;
	585	}
	586
	587	return 0;
	588	}
	589
	590	static void __exit videodev_exit(void)
	591	{
7f8ecfab HV	592	dev_t dev = MKDEV(VIDEO_MAJOR, 0);
7f8ecfab HV	593
27a5e6d3	594	class_unregister(&video_class);
7f8ecfab	595	unregister_chrdev_region(dev, VIDEO_NUM_DEVICES);
27a5e6d3 HV	596	}
	597
	598	module_init(videodev_init)
	599	module_exit(videodev_exit)
	600
	601	MODULE_AUTHOR("Alan Cox, Mauro Carvalho Chehab <mchehab@infradead.org>");
	602	MODULE_DESCRIPTION("Device registrar for Video4Linux drivers v2");
	603	MODULE_LICENSE("GPL");
cbb72b0f	604	MODULE_ALIAS_CHARDEV_MAJOR(VIDEO_MAJOR);
27a5e6d3 HV	605
	606
	607	/*
	608	* Local variables:
	609	* c-basic-offset: 8
	610	* End:
	611	*/