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/*

 * 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 <linuxcomp.h>

#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 sprintf26(buf,"%.*s\n",(int)sizeof(vfd->name),vfd->name);

}

static ssize_t show_dev(struct class_device *cd, char *buf)

{

        struct video_device *vfd = container_of(cd, struct video_device, class_dev);

        dev_t dev = MKDEV(VIDEO_MAJOR, vfd->minor);

        return print_dev_t(buf,dev);

}

static CLASS_DEVICE_ATTR(name, S_IRUGO, show_name, NULL);

static CLASS_DEVICE_ATTR(dev,  S_IRUGO, show_dev, 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

 */

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;

        /*  Copy arguments into temp kernel buffer  */

        switch (_IOC_DIR(cmd)) {

        case _IOC_NONE:

                parg = (void *)arg;

                break;

        case _IOC_READ: /* some v4l ioctls are marked wrong ... */

        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 (copy_from_user(parg, (void *)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 *)arg, parg, _IOC_SIZE(cmd)))

                        err = -EFAULT;

                break;

        }

out:

        if (mbuf)

                kfree(mbuf);

        return err;

}

/*

 * open/release helper functions -- handle exclusive opens

 */

extern 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;

}

extern int video_exclusive_release(struct inode *inode, struct file *file)

{

        struct  video_device *vfl = video_devdata(file);

        vfl->users--;

        return 0;

}

extern 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=240;

                        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 (-1 == nr) {

                /* use first free */

                for(i=base;i<end;i++)

                        if (NULL == video_device[i])

                                break;

                if (i == end) {

                        //up(&videodev_lock);

                        return -ENFILE;

                }

        } else {

                /* use the one the driver asked for */

                i = base+nr;

                if (NULL != video_device[i]) {

                        //up(&videodev_lock);

                        return -ENFILE;

                }

        }

        video_device[i]=vfd;

        vfd->minor=i;

        //up(&videodev_lock);

        sprintf26(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;

        strncpy(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);

        class_device_create_file(&vfd->class_dev,

                                 &class_device_attr_dev);

#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

 */

int __init videodev_init(void)

{

        printk(KERN_INFO "Linux video capture interface: v1.00\n");

        if (register_chrdev(VIDEO_MAJOR,VIDEO_NAME, &video_fops)) {

                printk("video_dev: unable to get major %d\n", VIDEO_MAJOR);

                return -EIO;

        }

        class_register(&video_class);

        return 0;

}

void __exit videodev_exit(void)

{

        class_unregister(&video_class);

        unregister_chrdev(VIDEO_MAJOR, VIDEO_NAME);

}

extern int linuxcomp_setfd(struct inode *i, int i_rdev);

/* Shark Inode emulation */

int videodev_open_inode(int num) {

  struct inode *i;

  i = (struct inode *)kmalloc(sizeof(struct inode),GFP_KERNEL);

  linuxcomp_setfd(i,num);

  if (video_open(i,NULL)) {

    kfree(i);

    return -1;

  }

  kfree(i);

  return 0;

}

extern int bttv_ioctl(struct inode *inode, struct file *file,

                        unsigned int cmd, unsigned long arg);

int videodev_ioctl_inode(int num,unsigned int cmd,unsigned long arg) {

  struct inode *i;

  int res;

  i = (struct inode *)kmalloc(sizeof(struct inode),GFP_KERNEL);

  linuxcomp_setfd(i,num);

  res = bttv_ioctl(i,NULL,cmd,arg);

  kfree(i);

  return res;

}

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:

 */