videodev.c

it s a source code for how to integrate your tvp5150 decoder with driver and how to capture an image

/*
 * Video capture interface for Linux Character Device Driver.
 *              based on  
 *              Alan Cox, <[e-mail]> video4linux 
 *
 * Author:      SW.LEE <[e-mail]>        
 *              2004 (C) Samsung Electronics 
 *              Modified for S3C2440/S3C24A0 Interface
 *
 * This file is released under the GPLv2
 */


#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 <linux/miscdevice.h>
#include <asm/uaccess.h>
#include <asm/system.h>
#include <asm/semaphore.h>



#include "camif.h"
#include "videodev.h"
#include "miscdevice.h"


static DECLARE_MUTEX(videodev_lock);

const char *fimc_version = "$Id: videodev.c,v 1.1.1.1 2004/04/27 03:52:50 swlee Exp $";

#define VIDEO_NAME              "video4linux"

/* 2.6 俊辑 哪颇老且锭 俊矾啊 惯积秦辑 积帆窃 */
#if 0 //坷府瘤朝 
static inline unsigned iminor(struct inode *inode)
{
    return MINOR(inode->i_rdev);
}

static inline unsigned imajor(struct inode *inode)
{
    return MAJOR(inode->i_rdev);
}
#endif




#define VIDEO_NUM_DEVICES   2 
static struct video_device *video_device[VIDEO_NUM_DEVICES];

static inline struct video_device * get_vd(int nr)
{
    if ( nr == CODEC_MINOR)
        return video_device[0];
    else {
        assert ( nr & PREVIEW_MINOR);
        return video_device[1];
    }
}

static inline void set_vd ( struct video_device * vd, int nr)
{
    if ( nr == CODEC_MINOR)
        video_device[0] = vd;
    else {
        assert ( nr & PREVIEW_MINOR);
        video_device[1] = vd;
    }
}

static inline int video_release(struct inode *inode, struct file *f)
{
    int minor = MINOR(inode->i_rdev);
    struct video_device *vfd;

    vfd = get_vd(minor);
#if 1 /* needed until all drivers are fixed */
    if (!vfd->release)
        return 0;
#endif
    vfd->release(vfd);
    return 0;
}

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)
{
    int minor = MINOR(inode->i_rdev);
    int err = 0;
    struct video_device *vfl;
    struct file_operations *old_fops;
    
    down(&videodev_lock);

    vfl = get_vd(minor);

    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;
}

/*
 * open/release helper functions -- handle exclusive opens
 */
extern int video_exclusive_open(struct inode *inode, struct file *file)
{
    struct  video_device *vfl = get_vd(MINOR(inode->i_rdev));
    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 = get_vd(MINOR(inode->i_rdev));
    vfl->users--;
    return 0;
}

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 = (void *)arg;
        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 *)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;
}


static struct file_operations video_fops=
{
    .owner      = THIS_MODULE,
    .llseek     = no_llseek,
    .open       = video_open,
    .release    = video_release,
};

static struct miscdevice codec_dev = {
    minor: CODEC_MINOR,
    name : "codec",
    fops : &video_fops
};

static struct miscdevice preview_dev = {
    minor: PREVIEW_MINOR,
    name : "preview",
    fops : &video_fops
};


/**
 *  video_register_device - register video4linux devices
 *  @vfd:  video device structure we want to register
 *  @type: type of device to register
 *  @nr:   minor number 
 *  
 *  Zero is returned on success.
 *      type : ignored.
 *      nr : 
 *           0 Codec index
 *           1 Preview index
 */
int video_register_device(struct video_device *vfd, int type, int nr)
{
    int ret=0;

    /* pick a minor number */
    down(&videodev_lock);
    set_vd (vfd, nr);
    vfd->minor=nr;
    up(&videodev_lock);

    switch (vfd->minor) {
        case CODEC_MINOR:
            ret = misc_register(&codec_dev);
            if (ret) {
                printk(KERN_ERR 
                        "can't misc_register : codec on minor=%d\n", CODEC_MINOR);
                panic(" Give me misc codec \n");
            }
            break;
        case PREVIEW_MINOR:
            ret = misc_register(&preview_dev);
            if (ret) {
                printk(KERN_ERR 
                        "can't misc_register (preview) on minor=%d\n", PREVIEW_MINOR);
                panic(" Give me misc preview \n");
            }
            break;
    }

#if 0 /* 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(get_vd(vfd->minor)!=vfd)
        panic("videodev: bad unregister");

    if (vfd->minor== CODEC_MINOR)
        misc_deregister(&codec_dev);
    else
        misc_deregister(&preview_dev);
    set_vd (NULL, vfd->minor);
    up(&videodev_lock);
}


/*
 *  Initialise video for linux
 */
 
static int __init videodev_init(void)
{
//  printk(KERN_INFO "FIMC2.0 Built:"__DATE__" "__TIME__"\n%s\n",fimc_version);
    return 0;
}

static void __exit videodev_exit(void)
{
}

module_init(videodev_init)
module_exit(videodev_exit)

EXPORT_SYMBOL(video_register_device);
EXPORT_SYMBOL(fimc_version);
EXPORT_SYMBOL(video_unregister_device);
EXPORT_SYMBOL(video_usercopy);
EXPORT_SYMBOL(video_exclusive_open);
EXPORT_SYMBOL(video_exclusive_release);


MODULE_AUTHOR("SW.LEE <[e-mail]>");
MODULE_DESCRIPTION("VideoDev For FIMC2.0 MISC Drivers");
MODULE_LICENSE("GPL");


/*
 * Local variables:
 * c-basic-offset: 8
 * End:
 */