/*
* Video capture interface for Linux
*
* 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.
*
* Author: Alan Cox, <alan@redhat.com>
*
* Fixes: 20000516 Claudio Matsuoka <claudio@conectiva.com>
* - Added procfs support
*/
#include <linux/module.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/smp_lock.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/devfs_fs_kernel.h>
#include <asm/uaccess.h>
#include <asm/system.h>
#include <asm/semaphore.h>
#include <linux/videodev.h>
#define VIDEO_NUM_DEVICES 256
#define VIDEO_NAME "video4linux"
/*
* sysfs stuff
*/
static ssize_t show_name(struct class_device *cd, char *buf)
{
struct video_device *vfd = container_of(cd, struct video_device, class_dev);
return sprintf(buf,"%.*s\n",(int)sizeof(vfd->name),vfd->name);
}
static CLASS_DEVICE_ATTR(name, S_IRUGO, show_name, NULL);
struct video_device *video_device_alloc(void)
{
struct video_device *vfd;
vfd = kmalloc(sizeof(*vfd),GFP_KERNEL);
if (NULL == vfd)
return NULL;
memset(vfd,0,sizeof(*vfd));
return vfd;
}
void video_device_release(struct video_device *vfd)
{
kfree(vfd);
}
static void video_release(struct class_device *cd)
{
struct video_device *vfd = container_of(cd, struct video_device, class_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,
.release = video_release,
};
/*
* Active devices
*/
static struct video_device *video_device[VIDEO_NUM_DEVICES];
static DECLARE_MUTEX(videodev_lock);
struct video_device* video_devdata(struct file *file)
{
return video_device[iminor(file->f_dentry->d_inode)];
}
/*
* Open a video device.
*/
static int video_open(struct inode *inode, struct file *file)
{
unsigned int minor = iminor(inode);
int err = 0;
struct video_device *vfl;
struct file_operations *old_fops;
if(minor>=VIDEO_NUM_DEVICES)
return -ENODEV;
down(&videodev_lock);
vfl=video_device[minor];
if(vfl==NULL) {
up(&videodev_lock);
request_module("char-major-%d-%d", VIDEO_MAJOR, minor);
down(&videodev_lock);
vfl=video_device[minor];
if (vfl==NULL) {
up(&videodev_lock);
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);
up(&videodev_lock);
return err;
}
/*
* helper function -- handles userspace copying for ioctl arguments
*/
static unsigned int
video_fix_command(unsigned int cmd)
{
switch (cmd) {
case VIDIOC_OVERLAY_OLD:
cmd = VIDIOC_OVERLAY;
break;
case VIDIOC_S_PARM_OLD:
cmd = VIDIOC_S_PARM;
break;
case VIDIOC_S_CTRL_OLD:
cmd = VIDIOC_S_CTRL;
break;
case VIDIOC_G_AUDIO_OLD:
cmd = VIDIOC_G_AUDIO;
break;
case VIDIOC_G_AUDOUT_OLD:
cmd = VIDIOC_G_AUDOUT;
break;
case VIDIOC_CROPCAP_OLD:
cmd = VIDIOC_CROPCAP;
break;
}
return cmd;
}
int
video_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))
{
char sbuf[128];
void *mbuf = NULL;
void *parg = NULL;
int err = -EINVAL;
cmd = video_fix_command(cmd);
/* Copy arguments into temp kernel buffer */
switch (_IOC_DIR(cmd)) {
case _IOC_NONE:
parg = NULL;
break;
case _IOC_READ:
case _IOC_WRITE:
case (_IOC_WRITE | _IOC_READ):
if (_IOC_SIZE(cmd) <= sizeof(sbuf)) {
parg = sbuf;
} else {
/* too big to allocate from stack */
mbuf = kmalloc(_IOC_SIZE(cmd),GFP_KERNEL);
if (NULL == mbuf)
return -ENOMEM;
parg = mbuf;
}
err = -EFAULT;
if (_IOC_DIR(cmd) & _IOC_WRITE)
if (copy_from_user(parg, (void __user *)arg, _IOC_SIZE(cmd)))
goto out;
break;
}
/* call driver */
err = func(inode, file, cmd, parg);
if (err == -ENOIOCTLCMD)
err = -EINVAL;
if (err < 0)
goto out;
/* Copy results into user buffer */
switch (_IOC_DIR(cmd))
{
case _IOC_READ:
case (_IOC_WRITE | _IOC_READ):
if (copy_to_user((void __user *)arg, parg, _IOC_SIZE(cmd)))
err = -EFAULT;
break;
}
out:
kfree(mbuf);
return err;
}
/*
* open/release helper functions -- handle exclusive opens
*/
int video_exclusive_open(struct inode *inode, struct file *file)
{
struct video_device *vfl = video_devdata(file);
int retval = 0;
down(&vfl->lock);
if (vfl->users) {
retval = -EBUSY;
} else {
vfl->users++;
}
up(&vfl->lock);
return retval;
}
int video_exclusive_release(struct inode *inode, struct file *file)
{
struct video_device *vfl = video_devdata(file);
vfl->users--;
return 0;
}
static struct file_operations video_fops;
/**
* 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(struct video_device *vfd, int type, int nr)
{
int i=0;
int base;
int end;
char *name_base;
switch(type)
{
case VFL_TYPE_GRABBER:
base=0;
end=64;
name_base = "video";
break;
case VFL_TYPE_VTX:
base=192;
end=224;
name_base = "vtx";
break;
case VFL_TYPE_VBI:
base=224;
end=256;
name_base = "vbi";
break;
case VFL_TYPE_RADIO:
base=64;
end=128;
name_base = "radio";
break;
default:
return -1;
}
/* pick a minor number */
down(&videodev_lock);
if (nr >= 0 && nr < end-base) {
/* use the one the driver asked for */
i = base+nr;
if (NULL != video_device[i]) {
up(&videodev_lock);
return -ENFILE;
}
} else {
/* use first free */
for(i=base;i<end;i++)
if (NULL == video_device[i])
break;
if (i == end) {
up(&videodev_lock);
return -ENFILE;
}
}
video_device[i]=vfd;
vfd->minor=i;
up(&videodev_lock);
sprintf(vfd->devfs_name, "v4l/%s%d", name_base, i - base);
devfs_mk_cdev(MKDEV(VIDEO_MAJOR, vfd->minor),
S_IFCHR | S_IRUSR | S_IWUSR, vfd->devfs_name);
init_MUTEX(&vfd->lock);
/* sysfs class */
memset(&vfd->class_dev, 0x00, sizeof(vfd->class_dev));
if (vfd->dev)
vfd->class_dev.dev = vfd->dev;
vfd->class_dev.class = &video_class;
vfd->class_dev.devt = MKDEV(VIDEO_MAJOR, vfd->minor);
strlcpy(vfd->class_dev.class_id, vfd->devfs_name + 4, BUS_ID_SIZE);
class_device_register(&vfd->class_dev);
class_device_create_file(&vfd->class_dev,
&class_device_attr_name);
#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;
}
/**
* 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)
{
down(&videodev_lock);
if(video_device[vfd->minor]!=vfd)
panic("videodev: bad unregister");
devfs_remove(vfd->devfs_name);
video_device[vfd->minor]=NULL;
class_device_unregister(&vfd->class_dev);
up(&videodev_lock);
}
static 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: v1.00\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)
EXPORT_SYMBOL(video_register_device);
EXPORT_SYMBOL(video_unregister_device);
EXPORT_SYMBOL(video_devdata);
EXPORT_SYMBOL(video_usercopy);
EXPORT_SYMBOL(video_exclusive_open);
EXPORT_SYMBOL(video_exclusive_release);
EXPORT_SYMBOL(video_device_alloc);
EXPORT_SYMBOL(video_device_release);
MODULE_AUTHOR("Alan Cox");
MODULE_DESCRIPTION("Device registrar for Video4Linux drivers");
MODULE_LICENSE("GPL");
/*
* Local variables:
* c-basic-offset: 8
* End:
*/
