/*
* 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@redhat.com> (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
};
struct video_device *video_device_alloc(void)
{
struct video_device *vfd;
vfd = kzalloc(sizeof(*vfd), GFP_KERNEL);
return vfd;
}
EXPORT_SYMBOL(video_device_alloc);
void video_device_release(struct video_device *vfd)
{
kfree(vfd);
}
EXPORT_SYMBOL(video_device_release);
static void video_release(struct device *cd)
{
struct video_device *vfd = container_of(cd, struct video_device, dev);
#if 1
/* needed until all drivers are fixed */
if (!vfd->release)
return;
#endif
vfd->release(vfd);
}
static struct class video_class = {
.name = VIDEO_NAME,
.dev_attrs = video_device_attrs,
.dev_release = video_release,
};
/*
* Active devices
*/
static struct video_device *video_device[VIDEO_NUM_DEVICES];
static DEFINE_MUTEX(videodev_lock);
struct video_device *video_devdata(struct file *file)
{
return video_device[iminor(file->f_path.dentry->d_inode)];
}
EXPORT_SYMBOL(video_devdata);
/*
* Open a video device - FIXME: Obsoleted
*/
static int video_open(struct inode *inode, struct file *file)
{
unsigned int minor = iminor(inode);
int err = 0;
struct video_device *vfl;
const struct file_operations *old_fops;
if (minor >= VIDEO_NUM_DEVICES)
return -ENODEV;
lock_kernel();
mutex_lock(&videodev_lock);
vfl = video_device[minor];
if (vfl == NULL) {
mutex_unlock(&videodev_lock);
request_module("char-major-%d-%d", VIDEO_MAJOR, minor);
mutex_lock(&videodev_lock);
vfl = video_device[minor];
if (vfl == NULL) {
mutex_unlock(&videodev_lock);
unlock_kernel();
return -ENODEV;
}
}
old_fops = file->f_op;
file->f_op = fops_get(vfl->fops);
if (file->f_op->open)
err = file->f_op->open(inode, file);
if (err) {
fops_put(file->f_op);
file->f_op = fops_get(old_fops);
}
fops_put(old_fops);
mutex_unlock(&videodev_lock);
unlock_kernel();
return err;
}
/*
* open/release helper functions -- handle exclusive opens
* Should be removed soon
*/
int video_exclusive_open(struct inode *inode, struct file *file)
{
struct video_device *vfl = video_devdata(file);
int retval = 0;
mutex_lock(&vfl->lock);
if (vfl->users)
retval = -EBUSY;
else
vfl->users++;
mutex_unlock(&vfl->lock);
return retval;
}
EXPORT_SYMBOL(video_exclusive_open);
int video_exclusive_release(struct inode *inode, struct file *file)
{
struct video_device *vfl = video_devdata(file);
vfl->users--;
return 0;
}
EXPORT_SYMBOL(video_exclusive_release);
/**
* 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;
}
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 - 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)
*
* 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 base;
int end;
int ret;
char *name_base;
switch (type) {
case VFL_TYPE_GRABBER:
base = MINOR_VFL_TYPE_GRABBER_MIN;
end = MINOR_VFL_TYPE_GRABBER_MAX+1;
name_base = "video";
break;
case VFL_TYPE_VTX:
base = MINOR_VFL_TYPE_VTX_MIN;
end = MINOR_VFL_TYPE_VTX_MAX+1;
name_base = "vtx";
break;
case VFL_TYPE_VBI:
base = MINOR_VFL_TYPE_VBI_MIN;
end = MINOR_VFL_TYPE_VBI_MAX+1;
name_base = "vbi";
break;
case VFL_TYPE_RADIO:
base = MINOR_VFL_TYPE_RADIO_MIN;
end = MINOR_VFL_TYPE_RADIO_MAX+1;
name_base = "radio";
break;
default:
printk(KERN_ERR "%s called with unknown type: %d\n",
__func__, type);
return -1;
}
/* pick a minor number */
mutex_lock(&videodev_lock);
if (nr >= 0 && nr < end-base) {
/* use the one the driver asked for */
i = base + nr;
if (NULL != video_device[i]) {
mutex_unlock(&videodev_lock);
return -ENFILE;
}
} else {
/* use first free */
for (i = base; i < end; i++)
if (NULL == video_device[i])
break;
if (i == end) {
mutex_unlock(&videodev_lock);
return -ENFILE;
}
}
video_device[i] = vfd;
vfd->minor = i;
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;
}
mutex_init(&vfd->lock);
/* sysfs class */
memset(&vfd->dev, 0x00, sizeof(vfd->dev));
vfd->dev.class = &video_class;
vfd->dev.devt = MKDEV(VIDEO_MAJOR, vfd->minor);
if (vfd->parent)
vfd->dev.parent = vfd->parent;
sprintf(vfd->dev.bus_id, "%s%d", name_base, i - base);
ret = device_register(&vfd->dev);
if (ret < 0) {
printk(KERN_ERR "%s: device_register failed\n", __func__);
goto fail_minor;
}
#if 1
/* needed until all drivers are fixed */
if (!vfd->release)
printk(KERN_WARNING "videodev: \"%s\" has no release callback. "
"Please fix your driver for proper sysfs support, see "
"http://lwn.net/Articles/36850/\n", vfd->name);
#endif
return 0;
fail_minor:
mutex_lock(&videodev_lock);
video_device[vfd->minor] = NULL;
vfd->minor = -1;
mutex_unlock(&videodev_lock);
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)
{
mutex_lock(&videodev_lock);
if (video_device[vfd->minor] != vfd)
panic("videodev: bad unregister");
video_device[vfd->minor] = NULL;
device_unregister(&vfd->dev);
mutex_unlock(&videodev_lock);
}
EXPORT_SYMBOL(video_unregister_device);
/*
* Video fs operations
*/
static const struct file_operations video_fops = {
.owner = THIS_MODULE,
.llseek = no_llseek,
.open = video_open,
};
/*
* Initialise video for linux
*/
static int __init videodev_init(void)
{
int ret;
printk(KERN_INFO "Linux video capture interface: v2.00\n");
if (register_chrdev(VIDEO_MAJOR, VIDEO_NAME, &video_fops)) {
printk(KERN_WARNING "video_dev: unable to get major %d\n", VIDEO_MAJOR);
return -EIO;
}
ret = class_register(&video_class);
if (ret < 0) {
unregister_chrdev(VIDEO_MAJOR, VIDEO_NAME);
printk(KERN_WARNING "video_dev: class_register failed\n");
return -EIO;
}
return 0;
}
static void __exit videodev_exit(void)
{
class_unregister(&video_class);
unregister_chrdev(VIDEO_MAJOR, VIDEO_NAME);
}
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:
*/
