2 * Video capture interface for Linux
4 * A generic video device interface for the LINUX operating system
5 * using a set of device structures/vectors for low level operations.
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License
9 * as published by the Free Software Foundation; either version
10 * 2 of the License, or (at your option) any later version.
12 * Author: Alan Cox, <alan@redhat.com>
14 * Fixes: 20000516 Claudio Matsuoka <claudio@conectiva.com>
15 * - Added procfs support
18 #include <linux/module.h>
19 #include <linux/types.h>
20 #include <linux/kernel.h>
21 #include <linux/sched.h>
22 #include <linux/smp_lock.h>
24 #include <linux/string.h>
25 #include <linux/errno.h>
26 #include <linux/init.h>
27 #include <linux/kmod.h>
28 #include <linux/slab.h>
29 #include <linux/devfs_fs_kernel.h>
30 #include <asm/uaccess.h>
31 #include <asm/system.h>
32 #include <asm/semaphore.h>
34 #include <linux/videodev.h>
36 #define VIDEO_NUM_DEVICES 256
37 #define VIDEO_NAME "video4linux"
43 static ssize_t show_name(struct class_device *cd, char *buf)
45 struct video_device *vfd = container_of(cd, struct video_device, class_dev);
46 return sprintf(buf,"%.*s\n",(int)sizeof(vfd->name),vfd->name);
49 static CLASS_DEVICE_ATTR(name, S_IRUGO, show_name, NULL);
51 struct video_device *video_device_alloc(void)
53 struct video_device *vfd;
55 vfd = kmalloc(sizeof(*vfd),GFP_KERNEL);
58 memset(vfd,0,sizeof(*vfd));
62 void video_device_release(struct video_device *vfd)
67 static void video_release(struct class_device *cd)
69 struct video_device *vfd = container_of(cd, struct video_device, class_dev);
72 /* needed until all drivers are fixed */
79 static struct class video_class = {
81 .release = video_release,
88 static struct video_device *video_device[VIDEO_NUM_DEVICES];
89 static DECLARE_MUTEX(videodev_lock);
91 struct video_device* video_devdata(struct file *file)
93 return video_device[iminor(file->f_dentry->d_inode)];
97 * Open a video device.
99 static int video_open(struct inode *inode, struct file *file)
101 unsigned int minor = iminor(inode);
103 struct video_device *vfl;
104 struct file_operations *old_fops;
106 if(minor>=VIDEO_NUM_DEVICES)
108 down(&videodev_lock);
109 vfl=video_device[minor];
112 request_module("char-major-%d-%d", VIDEO_MAJOR, minor);
113 down(&videodev_lock);
114 vfl=video_device[minor];
120 old_fops = file->f_op;
121 file->f_op = fops_get(vfl->fops);
123 err = file->f_op->open(inode,file);
125 fops_put(file->f_op);
126 file->f_op = fops_get(old_fops);
134 * helper function -- handles userspace copying for ioctl arguments
138 video_fix_command(unsigned int cmd)
141 case VIDIOC_OVERLAY_OLD:
142 cmd = VIDIOC_OVERLAY;
144 case VIDIOC_S_PARM_OLD:
147 case VIDIOC_S_CTRL_OLD:
150 case VIDIOC_G_AUDIO_OLD:
151 cmd = VIDIOC_G_AUDIO;
153 case VIDIOC_G_AUDOUT_OLD:
154 cmd = VIDIOC_G_AUDOUT;
156 case VIDIOC_CROPCAP_OLD:
157 cmd = VIDIOC_CROPCAP;
164 video_usercopy(struct inode *inode, struct file *file,
165 unsigned int cmd, unsigned long arg,
166 int (*func)(struct inode *inode, struct file *file,
167 unsigned int cmd, void *arg))
174 cmd = video_fix_command(cmd);
176 /* Copy arguments into temp kernel buffer */
177 switch (_IOC_DIR(cmd)) {
183 case (_IOC_WRITE | _IOC_READ):
184 if (_IOC_SIZE(cmd) <= sizeof(sbuf)) {
187 /* too big to allocate from stack */
188 mbuf = kmalloc(_IOC_SIZE(cmd),GFP_KERNEL);
195 if (_IOC_DIR(cmd) & _IOC_WRITE)
196 if (copy_from_user(parg, (void __user *)arg, _IOC_SIZE(cmd)))
202 err = func(inode, file, cmd, parg);
203 if (err == -ENOIOCTLCMD)
208 /* Copy results into user buffer */
209 switch (_IOC_DIR(cmd))
212 case (_IOC_WRITE | _IOC_READ):
213 if (copy_to_user((void __user *)arg, parg, _IOC_SIZE(cmd)))
224 * open/release helper functions -- handle exclusive opens
226 int video_exclusive_open(struct inode *inode, struct file *file)
228 struct video_device *vfl = video_devdata(file);
241 int video_exclusive_release(struct inode *inode, struct file *file)
243 struct video_device *vfl = video_devdata(file);
249 static struct file_operations video_fops;
252 * video_register_device - register video4linux devices
253 * @vfd: video device structure we want to register
254 * @type: type of device to register
255 * @nr: which device number (0 == /dev/video0, 1 == /dev/video1, ...
258 * The registration code assigns minor numbers based on the type
259 * requested. -ENFILE is returned in all the device slots for this
260 * category are full. If not then the minor field is set and the
261 * driver initialize function is called (if non %NULL).
263 * Zero is returned on success.
267 * %VFL_TYPE_GRABBER - A frame grabber
269 * %VFL_TYPE_VTX - A teletext device
271 * %VFL_TYPE_VBI - Vertical blank data (undecoded)
273 * %VFL_TYPE_RADIO - A radio card
276 int video_register_device(struct video_device *vfd, int type, int nr)
285 case VFL_TYPE_GRABBER:
309 /* pick a minor number */
310 down(&videodev_lock);
311 if (nr >= 0 && nr < end-base) {
312 /* use the one the driver asked for */
314 if (NULL != video_device[i]) {
320 for(i=base;i<end;i++)
321 if (NULL == video_device[i])
332 sprintf(vfd->devfs_name, "v4l/%s%d", name_base, i - base);
333 devfs_mk_cdev(MKDEV(VIDEO_MAJOR, vfd->minor),
334 S_IFCHR | S_IRUSR | S_IWUSR, vfd->devfs_name);
335 init_MUTEX(&vfd->lock);
338 memset(&vfd->class_dev, 0x00, sizeof(vfd->class_dev));
340 vfd->class_dev.dev = vfd->dev;
341 vfd->class_dev.class = &video_class;
342 vfd->class_dev.devt = MKDEV(VIDEO_MAJOR, vfd->minor);
343 strlcpy(vfd->class_dev.class_id, vfd->devfs_name + 4, BUS_ID_SIZE);
344 class_device_register(&vfd->class_dev);
345 class_device_create_file(&vfd->class_dev,
346 &class_device_attr_name);
349 /* needed until all drivers are fixed */
351 printk(KERN_WARNING "videodev: \"%s\" has no release callback. "
352 "Please fix your driver for proper sysfs support, see "
353 "http://lwn.net/Articles/36850/\n", vfd->name);
359 * video_unregister_device - unregister a video4linux device
360 * @vfd: the device to unregister
362 * This unregisters the passed device and deassigns the minor
363 * number. Future open calls will be met with errors.
366 void video_unregister_device(struct video_device *vfd)
368 down(&videodev_lock);
369 if(video_device[vfd->minor]!=vfd)
370 panic("videodev: bad unregister");
372 devfs_remove(vfd->devfs_name);
373 video_device[vfd->minor]=NULL;
374 class_device_unregister(&vfd->class_dev);
379 static struct file_operations video_fops=
381 .owner = THIS_MODULE,
387 * Initialise video for linux
390 static int __init videodev_init(void)
394 printk(KERN_INFO "Linux video capture interface: v1.00\n");
395 if (register_chrdev(VIDEO_MAJOR, VIDEO_NAME, &video_fops)) {
396 printk(KERN_WARNING "video_dev: unable to get major %d\n", VIDEO_MAJOR);
400 ret = class_register(&video_class);
402 unregister_chrdev(VIDEO_MAJOR, VIDEO_NAME);
403 printk(KERN_WARNING "video_dev: class_register failed\n");
410 static void __exit videodev_exit(void)
412 class_unregister(&video_class);
413 unregister_chrdev(VIDEO_MAJOR, VIDEO_NAME);
416 module_init(videodev_init)
417 module_exit(videodev_exit)
419 EXPORT_SYMBOL(video_register_device);
420 EXPORT_SYMBOL(video_unregister_device);
421 EXPORT_SYMBOL(video_devdata);
422 EXPORT_SYMBOL(video_usercopy);
423 EXPORT_SYMBOL(video_exclusive_open);
424 EXPORT_SYMBOL(video_exclusive_release);
425 EXPORT_SYMBOL(video_device_alloc);
426 EXPORT_SYMBOL(video_device_release);
428 MODULE_AUTHOR("Alan Cox");
429 MODULE_DESCRIPTION("Device registrar for Video4Linux drivers");
430 MODULE_LICENSE("GPL");