434 lines
9.5 KiB
C
434 lines
9.5 KiB
C
/*
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* Video capture interface for Linux
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*
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* A generic video device interface for the LINUX operating system
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* using a set of device structures/vectors for low level operations.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*
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* Author: Alan Cox, <alan@redhat.com>
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*
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* Fixes: 20000516 Claudio Matsuoka <claudio@conectiva.com>
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* - Added procfs support
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*/
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#include <linux/module.h>
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#include <linux/types.h>
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#include <linux/kernel.h>
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#include <linux/sched.h>
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#include <linux/smp_lock.h>
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#include <linux/mm.h>
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#include <linux/string.h>
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#include <linux/errno.h>
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#include <linux/init.h>
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#include <linux/kmod.h>
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#include <linux/slab.h>
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#include <linux/devfs_fs_kernel.h>
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#include <asm/uaccess.h>
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#include <asm/system.h>
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#include <linux/videodev.h>
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#define VIDEO_NUM_DEVICES 256
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#define VIDEO_NAME "video4linux"
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/*
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* sysfs stuff
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*/
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static ssize_t show_name(struct class_device *cd, char *buf)
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{
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struct video_device *vfd = container_of(cd, struct video_device, class_dev);
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return sprintf(buf,"%.*s\n",(int)sizeof(vfd->name),vfd->name);
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}
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static CLASS_DEVICE_ATTR(name, S_IRUGO, show_name, NULL);
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struct video_device *video_device_alloc(void)
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{
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struct video_device *vfd;
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vfd = kzalloc(sizeof(*vfd),GFP_KERNEL);
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return vfd;
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}
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void video_device_release(struct video_device *vfd)
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{
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kfree(vfd);
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}
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static void video_release(struct class_device *cd)
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{
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struct video_device *vfd = container_of(cd, struct video_device, class_dev);
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#if 1
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/* needed until all drivers are fixed */
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if (!vfd->release)
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return;
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#endif
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vfd->release(vfd);
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}
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static struct class video_class = {
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.name = VIDEO_NAME,
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.release = video_release,
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};
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/*
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* Active devices
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*/
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static struct video_device *video_device[VIDEO_NUM_DEVICES];
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static DEFINE_MUTEX(videodev_lock);
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struct video_device* video_devdata(struct file *file)
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{
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return video_device[iminor(file->f_dentry->d_inode)];
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}
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/*
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* Open a video device.
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*/
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static int video_open(struct inode *inode, struct file *file)
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{
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unsigned int minor = iminor(inode);
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int err = 0;
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struct video_device *vfl;
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const struct file_operations *old_fops;
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if(minor>=VIDEO_NUM_DEVICES)
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return -ENODEV;
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mutex_lock(&videodev_lock);
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vfl=video_device[minor];
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if(vfl==NULL) {
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mutex_unlock(&videodev_lock);
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request_module("char-major-%d-%d", VIDEO_MAJOR, minor);
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mutex_lock(&videodev_lock);
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vfl=video_device[minor];
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if (vfl==NULL) {
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mutex_unlock(&videodev_lock);
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return -ENODEV;
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}
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}
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old_fops = file->f_op;
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file->f_op = fops_get(vfl->fops);
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if(file->f_op->open)
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err = file->f_op->open(inode,file);
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if (err) {
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fops_put(file->f_op);
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file->f_op = fops_get(old_fops);
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}
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fops_put(old_fops);
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mutex_unlock(&videodev_lock);
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return err;
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}
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/*
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* helper function -- handles userspace copying for ioctl arguments
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*/
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static unsigned int
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video_fix_command(unsigned int cmd)
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{
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switch (cmd) {
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case VIDIOC_OVERLAY_OLD:
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cmd = VIDIOC_OVERLAY;
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break;
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case VIDIOC_S_PARM_OLD:
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cmd = VIDIOC_S_PARM;
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break;
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case VIDIOC_S_CTRL_OLD:
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cmd = VIDIOC_S_CTRL;
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break;
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case VIDIOC_G_AUDIO_OLD:
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cmd = VIDIOC_G_AUDIO;
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break;
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case VIDIOC_G_AUDOUT_OLD:
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cmd = VIDIOC_G_AUDOUT;
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break;
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case VIDIOC_CROPCAP_OLD:
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cmd = VIDIOC_CROPCAP;
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break;
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}
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return cmd;
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}
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int
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video_usercopy(struct inode *inode, struct file *file,
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unsigned int cmd, unsigned long arg,
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int (*func)(struct inode *inode, struct file *file,
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unsigned int cmd, void *arg))
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{
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char sbuf[128];
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void *mbuf = NULL;
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void *parg = NULL;
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int err = -EINVAL;
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cmd = video_fix_command(cmd);
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/* Copy arguments into temp kernel buffer */
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switch (_IOC_DIR(cmd)) {
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case _IOC_NONE:
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parg = NULL;
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break;
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case _IOC_READ:
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case _IOC_WRITE:
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case (_IOC_WRITE | _IOC_READ):
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if (_IOC_SIZE(cmd) <= sizeof(sbuf)) {
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parg = sbuf;
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} else {
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/* too big to allocate from stack */
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mbuf = kmalloc(_IOC_SIZE(cmd),GFP_KERNEL);
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if (NULL == mbuf)
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return -ENOMEM;
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parg = mbuf;
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}
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err = -EFAULT;
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if (_IOC_DIR(cmd) & _IOC_WRITE)
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if (copy_from_user(parg, (void __user *)arg, _IOC_SIZE(cmd)))
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goto out;
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break;
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}
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/* call driver */
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err = func(inode, file, cmd, parg);
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if (err == -ENOIOCTLCMD)
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err = -EINVAL;
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if (err < 0)
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goto out;
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/* Copy results into user buffer */
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switch (_IOC_DIR(cmd))
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{
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case _IOC_READ:
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case (_IOC_WRITE | _IOC_READ):
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if (copy_to_user((void __user *)arg, parg, _IOC_SIZE(cmd)))
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err = -EFAULT;
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break;
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}
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out:
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kfree(mbuf);
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return err;
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}
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/*
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* open/release helper functions -- handle exclusive opens
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*/
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int video_exclusive_open(struct inode *inode, struct file *file)
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{
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struct video_device *vfl = video_devdata(file);
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int retval = 0;
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mutex_lock(&vfl->lock);
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if (vfl->users) {
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retval = -EBUSY;
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} else {
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vfl->users++;
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}
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mutex_unlock(&vfl->lock);
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return retval;
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}
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int video_exclusive_release(struct inode *inode, struct file *file)
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{
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struct video_device *vfl = video_devdata(file);
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vfl->users--;
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return 0;
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}
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static struct file_operations video_fops;
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/**
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* video_register_device - register video4linux devices
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* @vfd: video device structure we want to register
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* @type: type of device to register
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* @nr: which device number (0 == /dev/video0, 1 == /dev/video1, ...
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* -1 == first free)
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*
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* The registration code assigns minor numbers based on the type
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* requested. -ENFILE is returned in all the device slots for this
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* category are full. If not then the minor field is set and the
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* driver initialize function is called (if non %NULL).
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*
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* Zero is returned on success.
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*
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* Valid types are
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*
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* %VFL_TYPE_GRABBER - A frame grabber
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*
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* %VFL_TYPE_VTX - A teletext device
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*
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* %VFL_TYPE_VBI - Vertical blank data (undecoded)
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*
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* %VFL_TYPE_RADIO - A radio card
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*/
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int video_register_device(struct video_device *vfd, int type, int nr)
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{
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int i=0;
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int base;
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int end;
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char *name_base;
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switch(type)
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{
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case VFL_TYPE_GRABBER:
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base=MINOR_VFL_TYPE_GRABBER_MIN;
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end=MINOR_VFL_TYPE_GRABBER_MAX+1;
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name_base = "video";
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break;
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case VFL_TYPE_VTX:
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base=MINOR_VFL_TYPE_VTX_MIN;
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end=MINOR_VFL_TYPE_VTX_MAX+1;
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name_base = "vtx";
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break;
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case VFL_TYPE_VBI:
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base=MINOR_VFL_TYPE_VBI_MIN;
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end=MINOR_VFL_TYPE_VBI_MAX+1;
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name_base = "vbi";
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break;
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case VFL_TYPE_RADIO:
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base=MINOR_VFL_TYPE_RADIO_MIN;
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end=MINOR_VFL_TYPE_RADIO_MAX+1;
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name_base = "radio";
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break;
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default:
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return -1;
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}
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/* pick a minor number */
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mutex_lock(&videodev_lock);
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if (nr >= 0 && nr < end-base) {
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/* use the one the driver asked for */
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i = base+nr;
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if (NULL != video_device[i]) {
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mutex_unlock(&videodev_lock);
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return -ENFILE;
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}
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} else {
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/* use first free */
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for(i=base;i<end;i++)
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if (NULL == video_device[i])
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break;
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if (i == end) {
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mutex_unlock(&videodev_lock);
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return -ENFILE;
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}
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}
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video_device[i]=vfd;
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vfd->minor=i;
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mutex_unlock(&videodev_lock);
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sprintf(vfd->devfs_name, "v4l/%s%d", name_base, i - base);
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devfs_mk_cdev(MKDEV(VIDEO_MAJOR, vfd->minor),
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S_IFCHR | S_IRUSR | S_IWUSR, vfd->devfs_name);
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mutex_init(&vfd->lock);
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/* sysfs class */
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memset(&vfd->class_dev, 0x00, sizeof(vfd->class_dev));
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if (vfd->dev)
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vfd->class_dev.dev = vfd->dev;
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vfd->class_dev.class = &video_class;
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vfd->class_dev.devt = MKDEV(VIDEO_MAJOR, vfd->minor);
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strlcpy(vfd->class_dev.class_id, vfd->devfs_name + 4, BUS_ID_SIZE);
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class_device_register(&vfd->class_dev);
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class_device_create_file(&vfd->class_dev,
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&class_device_attr_name);
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#if 1
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/* needed until all drivers are fixed */
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if (!vfd->release)
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printk(KERN_WARNING "videodev: \"%s\" has no release callback. "
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"Please fix your driver for proper sysfs support, see "
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"http://lwn.net/Articles/36850/\n", vfd->name);
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#endif
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return 0;
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}
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/**
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* video_unregister_device - unregister a video4linux device
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* @vfd: the device to unregister
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*
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* This unregisters the passed device and deassigns the minor
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* number. Future open calls will be met with errors.
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*/
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void video_unregister_device(struct video_device *vfd)
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{
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mutex_lock(&videodev_lock);
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if(video_device[vfd->minor]!=vfd)
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panic("videodev: bad unregister");
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devfs_remove(vfd->devfs_name);
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video_device[vfd->minor]=NULL;
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class_device_unregister(&vfd->class_dev);
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mutex_unlock(&videodev_lock);
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}
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static struct file_operations video_fops=
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{
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.owner = THIS_MODULE,
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.llseek = no_llseek,
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.open = video_open,
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};
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/*
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* Initialise video for linux
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*/
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static int __init videodev_init(void)
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{
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int ret;
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printk(KERN_INFO "Linux video capture interface: v1.00\n");
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if (register_chrdev(VIDEO_MAJOR, VIDEO_NAME, &video_fops)) {
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printk(KERN_WARNING "video_dev: unable to get major %d\n", VIDEO_MAJOR);
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return -EIO;
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}
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ret = class_register(&video_class);
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if (ret < 0) {
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unregister_chrdev(VIDEO_MAJOR, VIDEO_NAME);
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printk(KERN_WARNING "video_dev: class_register failed\n");
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return -EIO;
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}
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return 0;
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}
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static void __exit videodev_exit(void)
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{
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class_unregister(&video_class);
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unregister_chrdev(VIDEO_MAJOR, VIDEO_NAME);
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}
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module_init(videodev_init)
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module_exit(videodev_exit)
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EXPORT_SYMBOL(video_register_device);
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EXPORT_SYMBOL(video_unregister_device);
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EXPORT_SYMBOL(video_devdata);
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EXPORT_SYMBOL(video_usercopy);
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EXPORT_SYMBOL(video_exclusive_open);
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EXPORT_SYMBOL(video_exclusive_release);
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EXPORT_SYMBOL(video_device_alloc);
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EXPORT_SYMBOL(video_device_release);
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MODULE_AUTHOR("Alan Cox");
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MODULE_DESCRIPTION("Device registrar for Video4Linux drivers");
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MODULE_LICENSE("GPL");
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/*
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* Local variables:
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* c-basic-offset: 8
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* End:
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*/
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