/*
* 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>
#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 *vfd = container_of(cd, struct video_device, dev);
return sprintf(buf, "%i\n", vfd->index);
}
static ssize_t show_name(struct device *cd,
struct device_attribute *attr, char *buf)
{
struct video_device *vfd = container_of(cd, struct video_device, dev);
return sprintf(buf, "%.*s\n", (int)sizeof(vfd->name), vfd->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 *vfd)
{
kfree(vfd);
}
EXPORT_SYMBOL(video_device_release);
void video_device_release_empty(struct video_device *vfd)
{
/* Do nothing */
/* Only valid when the video_device struct is a static. */
}
EXPORT_SYMBOL(video_device_release_empty);
/* Called when the last user of the character device is gone. */
static void v4l2_chardev_release(struct kobject *kobj)
{
struct video_device *vfd = container_of(kobj, struct video_device, cdev.kobj);
mutex_lock(&videodev_lock);
if (video_device[vfd->minor] != vfd) {
mutex_unlock(&videodev_lock);
BUG();
return;
}
/* Free up this device for reuse */
video_device[vfd->minor] = NULL;
clear_bit(vfd->num, video_nums[vfd->vfl_type]);
mutex_unlock(&videodev_lock);
/* Release the character device */
vfd->cdev_release(kobj);
/* Release video_device and perform other
cleanups as needed. */
if (vfd->release)
vfd->release(vfd);
}
/* The new kobj_type for the character device */
static struct kobj_type v4l2_ktype_cdev_default = {
.release = v4l2_chardev_release,
};
static void video_release(struct device *cd)
{
struct video_device *vfd = container_of(cd, struct video_device, dev);
/* It's now safe to delete the char device.
This will either trigger the v4l2_chardev_release immediately (if
the refcount goes to 0) or later when the last user of the
character device closes it. */
cdev_del(&vfd->cdev);
}
static struct class video_class = {
.name = VIDEO_NAME,
.dev_attrs = video_device_attrs,
.dev_release = video_release,
};
struct video_device *video_devdata(struct file *file)
{
return video_device[iminor(file->f_path.dentry->d_inode)];
}
EXPORT_SYMBOL(video_devdata);
/**
* get_index - assign stream number based on parent device
* @vdev: video_device to assign index number to, vdev->dev should be assigned
* @num: -1 if auto assign, requested number otherwise
*
*
* returns -ENFILE if num is already in use, a free index number if
* successful.
*/
static int get_index(struct video_device *vdev, int num)
{
u32 used = 0;
const int max_index = sizeof(used) * 8 - 1;
int i;
/* Currently a single v4l driver instance cannot create more than
32 devices.
Increase to u64 or an array of u32 if more are needed. */
if (num > max_index) {
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 0. */
if (vdev->parent == NULL)
return 0;
for (i = 0; i < VIDEO_NUM_DEVICES; i++) {
if (video_device[i] != NULL &&
video_device[i] != vdev &&
video_device[i]->parent == vdev->parent) {
used |= 1 << video_device[i]->index;
}
}
if (num >= 0) {
if (used & (1 << num))
return -ENFILE;
return num;
}
i = ffz(used);
return i > max_index ? -ENFILE : i;
}
static const struct file_operations video_fops;
int video_register_device(struct video_device *vfd, int type, int nr)
{
return video_register_device_index(vfd, type, nr, -1);
}
EXPORT_SYMBOL(video_register_device);
/**
* video_register_device_index - register video4linux devices
* @vfd: 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 *vfd, 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(vfd);
/* the release callback MUST be present */
BUG_ON(!vfd->release);
if (vfd == NULL)
return -EINVAL;
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;
}
vfd->vfl_type = type;
#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
/* Initialize the character device */
cdev_init(&vfd->cdev, vfd->fops);
vfd->cdev.owner = vfd->fops->owner;
/* 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
vfd->minor = i + minor_offset;
vfd->num = nr;
set_bit(nr, video_nums[type]);
BUG_ON(video_device[vfd->minor]);
video_device[vfd->minor] = vfd;
ret = get_index(vfd, index);
vfd->index = ret;
mutex_unlock(&videodev_lock);
if (ret < 0) {
printk(KERN_ERR "%s: get_index failed\n", __func__);
goto fail_minor;
}
ret = cdev_add(&vfd->cdev, MKDEV(VIDEO_MAJOR, vfd->minor), 1);
if (ret < 0) {
printk(KERN_ERR "%s: cdev_add failed\n", __func__);
goto fail_minor;
}
/* sysfs class */
memset(&vfd->dev, 0, sizeof(vfd->dev));
/* The memset above cleared the device's drvdata, so
put back the copy we made earlier. */
video_set_drvdata(vfd, priv);
vfd->dev.class = &video_class;
vfd->dev.devt = MKDEV(VIDEO_MAJOR, vfd->minor);
if (vfd->parent)
vfd->dev.parent = vfd->parent;
dev_set_name(&vfd->dev, "%s%d", name_base, nr);
ret = device_register(&vfd->dev);
if (ret < 0) {
printk(KERN_ERR "%s: device_register failed\n", __func__);
goto del_cdev;
}
/* Remember the cdev's release function */
vfd->cdev_release = vfd->cdev.kobj.ktype->release;
/* Install our own */
vfd->cdev.kobj.ktype = &v4l2_ktype_cdev_default;
return 0;
del_cdev:
cdev_del(&vfd->cdev);
fail_minor:
mutex_lock(&videodev_lock);
video_device[vfd->minor] = NULL;
clear_bit(vfd->num, video_nums[type]);
mutex_unlock(&videodev_lock);
vfd->minor = -1;
return ret;
}
EXPORT_SYMBOL(video_register_device_index);
/**
* video_unregister_device - unregister a video4linux device
* @vfd: the device to unregister
*
* This unregisters the passed device and deassigns the minor
* number. Future open calls will be met with errors.
*/
void video_unregister_device(struct video_device *vfd)
{
device_unregister(&vfd->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");
/*
* Local variables:
* c-basic-offset: 8
* End:
*/
