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 ssize_t show_dev(struct class_device *cd, char *buf)
51 struct video_device *vfd = container_of(cd, struct video_device, class_dev);
52 dev_t dev = MKDEV(VIDEO_MAJOR, vfd->minor);
53 return print_dev_t(buf,dev);
56 static CLASS_DEVICE_ATTR(name, S_IRUGO, show_name, NULL);
57 static CLASS_DEVICE_ATTR(dev, S_IRUGO, show_dev, NULL);
59 struct video_device *video_device_alloc(void)
61 struct video_device *vfd;
63 vfd = kmalloc(sizeof(*vfd),GFP_KERNEL);
66 memset(vfd,0,sizeof(*vfd));
70 void video_device_release(struct video_device *vfd)
75 static void video_release(struct class_device *cd)
77 struct video_device *vfd = container_of(cd, struct video_device, class_dev);
79 #if 1 /* needed until all drivers are fixed */
86 static struct class video_class = {
88 .release = video_release,
95 static struct video_device *video_device[VIDEO_NUM_DEVICES];
96 static DECLARE_MUTEX(videodev_lock);
98 struct video_device* video_devdata(struct file *file)
100 return video_device[iminor(file->f_dentry->d_inode)];
104 * Open a video device.
106 static int video_open(struct inode *inode, struct file *file)
108 unsigned int minor = iminor(inode);
110 struct video_device *vfl;
111 struct file_operations *old_fops;
113 if(minor>=VIDEO_NUM_DEVICES)
115 down(&videodev_lock);
116 vfl=video_device[minor];
119 request_module("char-major-%d-%d", VIDEO_MAJOR, minor);
120 down(&videodev_lock);
121 vfl=video_device[minor];
127 old_fops = file->f_op;
128 file->f_op = fops_get(vfl->fops);
130 err = file->f_op->open(inode,file);
132 fops_put(file->f_op);
133 file->f_op = fops_get(old_fops);
141 * helper function -- handles userspace copying for ioctl arguments
145 video_fix_command(unsigned int cmd)
148 case VIDIOC_OVERLAY_OLD:
149 cmd = VIDIOC_OVERLAY;
151 case VIDIOC_S_PARM_OLD:
154 case VIDIOC_S_CTRL_OLD:
157 case VIDIOC_G_AUDIO_OLD:
158 cmd = VIDIOC_G_AUDIO;
160 case VIDIOC_G_AUDOUT_OLD:
161 cmd = VIDIOC_G_AUDOUT;
163 case VIDIOC_CROPCAP_OLD:
164 cmd = VIDIOC_CROPCAP;
171 video_usercopy(struct inode *inode, struct file *file,
172 unsigned int cmd, unsigned long arg,
173 int (*func)(struct inode *inode, struct file *file,
174 unsigned int cmd, void *arg))
181 cmd = video_fix_command(cmd);
183 /* Copy arguments into temp kernel buffer */
184 switch (_IOC_DIR(cmd)) {
190 case (_IOC_WRITE | _IOC_READ):
191 if (_IOC_SIZE(cmd) <= sizeof(sbuf)) {
194 /* too big to allocate from stack */
195 mbuf = kmalloc(_IOC_SIZE(cmd),GFP_KERNEL);
202 if (_IOC_DIR(cmd) & _IOC_WRITE)
203 if (copy_from_user(parg, (void *)arg, _IOC_SIZE(cmd)))
209 err = func(inode, file, cmd, parg);
210 if (err == -ENOIOCTLCMD)
215 /* Copy results into user buffer */
216 switch (_IOC_DIR(cmd))
219 case (_IOC_WRITE | _IOC_READ):
220 if (copy_to_user((void *)arg, parg, _IOC_SIZE(cmd)))
232 * open/release helper functions -- handle exclusive opens
234 extern int video_exclusive_open(struct inode *inode, struct file *file)
236 struct video_device *vfl = video_devdata(file);
249 extern int video_exclusive_release(struct inode *inode, struct file *file)
251 struct video_device *vfl = video_devdata(file);
257 extern struct file_operations video_fops;
260 * video_register_device - register video4linux devices
261 * @vfd: video device structure we want to register
262 * @type: type of device to register
263 * @nr: which device number (0 == /dev/video0, 1 == /dev/video1, ...
266 * The registration code assigns minor numbers based on the type
267 * requested. -ENFILE is returned in all the device slots for this
268 * category are full. If not then the minor field is set and the
269 * driver initialize function is called (if non %NULL).
271 * Zero is returned on success.
275 * %VFL_TYPE_GRABBER - A frame grabber
277 * %VFL_TYPE_VTX - A teletext device
279 * %VFL_TYPE_VBI - Vertical blank data (undecoded)
281 * %VFL_TYPE_RADIO - A radio card
284 int video_register_device(struct video_device *vfd, int type, int nr)
293 case VFL_TYPE_GRABBER:
317 /* pick a minor number */
318 down(&videodev_lock);
319 if (nr >= 0 && nr < end-base) {
320 /* use the one the driver asked for */
322 if (NULL != video_device[i]) {
328 for(i=base;i<end;i++)
329 if (NULL == video_device[i])
340 sprintf(vfd->devfs_name, "v4l/%s%d", name_base, i - base);
341 devfs_mk_cdev(MKDEV(VIDEO_MAJOR, vfd->minor),
342 S_IFCHR | S_IRUSR | S_IWUSR, vfd->devfs_name);
343 init_MUTEX(&vfd->lock);
346 memset(&vfd->class_dev, 0x00, sizeof(vfd->class_dev));
348 vfd->class_dev.dev = vfd->dev;
349 vfd->class_dev.class = &video_class;
350 strlcpy(vfd->class_dev.class_id, vfd->devfs_name + 4, BUS_ID_SIZE);
351 class_device_register(&vfd->class_dev);
352 class_device_create_file(&vfd->class_dev,
353 &class_device_attr_name);
354 class_device_create_file(&vfd->class_dev,
355 &class_device_attr_dev);
357 #if 1 /* needed until all drivers are fixed */
359 printk(KERN_WARNING "videodev: \"%s\" has no release callback. "
360 "Please fix your driver for proper sysfs support, see "
361 "http://lwn.net/Articles/36850/\n", vfd->name);
367 * video_unregister_device - unregister a video4linux device
368 * @vfd: the device to unregister
370 * This unregisters the passed device and deassigns the minor
371 * number. Future open calls will be met with errors.
374 void video_unregister_device(struct video_device *vfd)
376 down(&videodev_lock);
377 if(video_device[vfd->minor]!=vfd)
378 panic("videodev: bad unregister");
380 devfs_remove(vfd->devfs_name);
381 video_device[vfd->minor]=NULL;
382 class_device_unregister(&vfd->class_dev);
387 static struct file_operations video_fops=
389 .owner = THIS_MODULE,
395 * Initialise video for linux
398 static int __init videodev_init(void)
400 printk(KERN_INFO "Linux video capture interface: v1.00\n");
401 if (register_chrdev(VIDEO_MAJOR,VIDEO_NAME, &video_fops)) {
402 printk("video_dev: unable to get major %d\n", VIDEO_MAJOR);
405 class_register(&video_class);
409 static void __exit videodev_exit(void)
411 class_unregister(&video_class);
412 unregister_chrdev(VIDEO_MAJOR, VIDEO_NAME);
415 module_init(videodev_init)
416 module_exit(videodev_exit)
418 EXPORT_SYMBOL(video_register_device);
419 EXPORT_SYMBOL(video_unregister_device);
420 EXPORT_SYMBOL(video_devdata);
421 EXPORT_SYMBOL(video_usercopy);
422 EXPORT_SYMBOL(video_exclusive_open);
423 EXPORT_SYMBOL(video_exclusive_release);
424 EXPORT_SYMBOL(video_device_alloc);
425 EXPORT_SYMBOL(video_device_release);
427 MODULE_AUTHOR("Alan Cox");
428 MODULE_DESCRIPTION("Device registrar for Video4Linux drivers");
429 MODULE_LICENSE("GPL");