1 /*
2 * Video capture interface for Linux version 2
3 *
4 * A generic video device interface for the LINUX operating system
5 * using a set of device structures/vectors for low level operations.
6 *
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.
11 *
12 * Authors: Alan Cox, <alan@lxorguk.ukuu.org.uk> (version 1)
13 * Mauro Carvalho Chehab <mchehab@infradead.org> (version 2)
14 *
15 * Fixes: 20000516 Claudio Matsuoka <claudio@conectiva.com>
16 * - Added procfs support
17 */
18
19 #include <linux/module.h>
20 #include <linux/types.h>
21 #include <linux/kernel.h>
22 #include <linux/mm.h>
23 #include <linux/string.h>
24 #include <linux/errno.h>
25 #include <linux/init.h>
26 #include <linux/kmod.h>
27 #include <linux/slab.h>
28 #include <asm/uaccess.h>
29 #include <asm/system.h>
30
31 #include <media/v4l2-common.h>
32 #include <media/v4l2-device.h>
33 #include <media/v4l2-ioctl.h>
34
35 #define VIDEO_NUM_DEVICES 256
36 #define VIDEO_NAME "video4linux"
37
38 /*
39 * sysfs stuff
40 */
41
show_index(struct device * cd,struct device_attribute * attr,char * buf)42 static ssize_t show_index(struct device *cd,
43 struct device_attribute *attr, char *buf)
44 {
45 struct video_device *vdev = to_video_device(cd);
46
47 return sprintf(buf, "%i\n", vdev->index);
48 }
49
show_name(struct device * cd,struct device_attribute * attr,char * buf)50 static ssize_t show_name(struct device *cd,
51 struct device_attribute *attr, char *buf)
52 {
53 struct video_device *vdev = to_video_device(cd);
54
55 return sprintf(buf, "%.*s\n", (int)sizeof(vdev->name), vdev->name);
56 }
57
58 static struct device_attribute video_device_attrs[] = {
59 __ATTR(name, S_IRUGO, show_name, NULL),
60 __ATTR(index, S_IRUGO, show_index, NULL),
61 __ATTR_NULL
62 };
63
64 /*
65 * Active devices
66 */
67 static struct video_device *video_device[VIDEO_NUM_DEVICES];
68 static DEFINE_MUTEX(videodev_lock);
69 static DECLARE_BITMAP(devnode_nums[VFL_TYPE_MAX], VIDEO_NUM_DEVICES);
70
71 /* Device node utility functions */
72
73 /* Note: these utility functions all assume that vfl_type is in the range
74 [0, VFL_TYPE_MAX-1]. */
75
76 #ifdef CONFIG_VIDEO_FIXED_MINOR_RANGES
77 /* Return the bitmap corresponding to vfl_type. */
devnode_bits(int vfl_type)78 static inline unsigned long *devnode_bits(int vfl_type)
79 {
80 /* Any types not assigned to fixed minor ranges must be mapped to
81 one single bitmap for the purposes of finding a free node number
82 since all those unassigned types use the same minor range. */
83 int idx = (vfl_type > VFL_TYPE_RADIO) ? VFL_TYPE_MAX - 1 : vfl_type;
84
85 return devnode_nums[idx];
86 }
87 #else
88 /* Return the bitmap corresponding to vfl_type. */
devnode_bits(int vfl_type)89 static inline unsigned long *devnode_bits(int vfl_type)
90 {
91 return devnode_nums[vfl_type];
92 }
93 #endif
94
95 /* Mark device node number vdev->num as used */
devnode_set(struct video_device * vdev)96 static inline void devnode_set(struct video_device *vdev)
97 {
98 set_bit(vdev->num, devnode_bits(vdev->vfl_type));
99 }
100
101 /* Mark device node number vdev->num as unused */
devnode_clear(struct video_device * vdev)102 static inline void devnode_clear(struct video_device *vdev)
103 {
104 clear_bit(vdev->num, devnode_bits(vdev->vfl_type));
105 }
106
107 /* Try to find a free device node number in the range [from, to> */
devnode_find(struct video_device * vdev,int from,int to)108 static inline int devnode_find(struct video_device *vdev, int from, int to)
109 {
110 return find_next_zero_bit(devnode_bits(vdev->vfl_type), to, from);
111 }
112
video_device_alloc(void)113 struct video_device *video_device_alloc(void)
114 {
115 return kzalloc(sizeof(struct video_device), GFP_KERNEL);
116 }
117 EXPORT_SYMBOL(video_device_alloc);
118
video_device_release(struct video_device * vdev)119 void video_device_release(struct video_device *vdev)
120 {
121 kfree(vdev);
122 }
123 EXPORT_SYMBOL(video_device_release);
124
video_device_release_empty(struct video_device * vdev)125 void video_device_release_empty(struct video_device *vdev)
126 {
127 /* Do nothing */
128 /* Only valid when the video_device struct is a static. */
129 }
130 EXPORT_SYMBOL(video_device_release_empty);
131
video_get(struct video_device * vdev)132 static inline void video_get(struct video_device *vdev)
133 {
134 get_device(&vdev->dev);
135 }
136
video_put(struct video_device * vdev)137 static inline void video_put(struct video_device *vdev)
138 {
139 put_device(&vdev->dev);
140 }
141
142 /* Called when the last user of the video device exits. */
v4l2_device_release(struct device * cd)143 static void v4l2_device_release(struct device *cd)
144 {
145 struct video_device *vdev = to_video_device(cd);
146 struct v4l2_device *v4l2_dev = vdev->v4l2_dev;
147
148 mutex_lock(&videodev_lock);
149 if (video_device[vdev->minor] != vdev) {
150 mutex_unlock(&videodev_lock);
151 /* should not happen */
152 WARN_ON(1);
153 return;
154 }
155
156 /* Free up this device for reuse */
157 video_device[vdev->minor] = NULL;
158
159 /* Delete the cdev on this minor as well */
160 cdev_del(vdev->cdev);
161 /* Just in case some driver tries to access this from
162 the release() callback. */
163 vdev->cdev = NULL;
164
165 /* Mark device node number as free */
166 devnode_clear(vdev);
167
168 mutex_unlock(&videodev_lock);
169
170 /* Release video_device and perform other
171 cleanups as needed. */
172 vdev->release(vdev);
173
174 /* Decrease v4l2_device refcount */
175 if (v4l2_dev)
176 v4l2_device_put(v4l2_dev);
177 }
178
179 static struct class video_class = {
180 .name = VIDEO_NAME,
181 .dev_attrs = video_device_attrs,
182 };
183
video_devdata(struct file * file)184 struct video_device *video_devdata(struct file *file)
185 {
186 return video_device[iminor(file->f_path.dentry->d_inode)];
187 }
188 EXPORT_SYMBOL(video_devdata);
189
190
191 /* Priority handling */
192
prio_is_valid(enum v4l2_priority prio)193 static inline bool prio_is_valid(enum v4l2_priority prio)
194 {
195 return prio == V4L2_PRIORITY_BACKGROUND ||
196 prio == V4L2_PRIORITY_INTERACTIVE ||
197 prio == V4L2_PRIORITY_RECORD;
198 }
199
v4l2_prio_init(struct v4l2_prio_state * global)200 void v4l2_prio_init(struct v4l2_prio_state *global)
201 {
202 memset(global, 0, sizeof(*global));
203 }
204 EXPORT_SYMBOL(v4l2_prio_init);
205
v4l2_prio_change(struct v4l2_prio_state * global,enum v4l2_priority * local,enum v4l2_priority new)206 int v4l2_prio_change(struct v4l2_prio_state *global, enum v4l2_priority *local,
207 enum v4l2_priority new)
208 {
209 if (!prio_is_valid(new))
210 return -EINVAL;
211 if (*local == new)
212 return 0;
213
214 atomic_inc(&global->prios[new]);
215 if (prio_is_valid(*local))
216 atomic_dec(&global->prios[*local]);
217 *local = new;
218 return 0;
219 }
220 EXPORT_SYMBOL(v4l2_prio_change);
221
v4l2_prio_open(struct v4l2_prio_state * global,enum v4l2_priority * local)222 void v4l2_prio_open(struct v4l2_prio_state *global, enum v4l2_priority *local)
223 {
224 v4l2_prio_change(global, local, V4L2_PRIORITY_DEFAULT);
225 }
226 EXPORT_SYMBOL(v4l2_prio_open);
227
v4l2_prio_close(struct v4l2_prio_state * global,enum v4l2_priority local)228 void v4l2_prio_close(struct v4l2_prio_state *global, enum v4l2_priority local)
229 {
230 if (prio_is_valid(local))
231 atomic_dec(&global->prios[local]);
232 }
233 EXPORT_SYMBOL(v4l2_prio_close);
234
v4l2_prio_max(struct v4l2_prio_state * global)235 enum v4l2_priority v4l2_prio_max(struct v4l2_prio_state *global)
236 {
237 if (atomic_read(&global->prios[V4L2_PRIORITY_RECORD]) > 0)
238 return V4L2_PRIORITY_RECORD;
239 if (atomic_read(&global->prios[V4L2_PRIORITY_INTERACTIVE]) > 0)
240 return V4L2_PRIORITY_INTERACTIVE;
241 if (atomic_read(&global->prios[V4L2_PRIORITY_BACKGROUND]) > 0)
242 return V4L2_PRIORITY_BACKGROUND;
243 return V4L2_PRIORITY_UNSET;
244 }
245 EXPORT_SYMBOL(v4l2_prio_max);
246
v4l2_prio_check(struct v4l2_prio_state * global,enum v4l2_priority local)247 int v4l2_prio_check(struct v4l2_prio_state *global, enum v4l2_priority local)
248 {
249 return (local < v4l2_prio_max(global)) ? -EBUSY : 0;
250 }
251 EXPORT_SYMBOL(v4l2_prio_check);
252
253
v4l2_read(struct file * filp,char __user * buf,size_t sz,loff_t * off)254 static ssize_t v4l2_read(struct file *filp, char __user *buf,
255 size_t sz, loff_t *off)
256 {
257 struct video_device *vdev = video_devdata(filp);
258 int ret = -ENODEV;
259
260 if (!vdev->fops->read)
261 return -EINVAL;
262 if (vdev->lock && mutex_lock_interruptible(vdev->lock))
263 return -ERESTARTSYS;
264 if (video_is_registered(vdev))
265 ret = vdev->fops->read(filp, buf, sz, off);
266 if (vdev->lock)
267 mutex_unlock(vdev->lock);
268 return ret;
269 }
270
v4l2_write(struct file * filp,const char __user * buf,size_t sz,loff_t * off)271 static ssize_t v4l2_write(struct file *filp, const char __user *buf,
272 size_t sz, loff_t *off)
273 {
274 struct video_device *vdev = video_devdata(filp);
275 int ret = -ENODEV;
276
277 if (!vdev->fops->write)
278 return -EINVAL;
279 if (vdev->lock && mutex_lock_interruptible(vdev->lock))
280 return -ERESTARTSYS;
281 if (video_is_registered(vdev))
282 ret = vdev->fops->write(filp, buf, sz, off);
283 if (vdev->lock)
284 mutex_unlock(vdev->lock);
285 return ret;
286 }
287
v4l2_poll(struct file * filp,struct poll_table_struct * poll)288 static unsigned int v4l2_poll(struct file *filp, struct poll_table_struct *poll)
289 {
290 struct video_device *vdev = video_devdata(filp);
291 int ret = POLLERR | POLLHUP;
292
293 if (!vdev->fops->poll)
294 return DEFAULT_POLLMASK;
295 if (vdev->lock)
296 mutex_lock(vdev->lock);
297 if (video_is_registered(vdev))
298 ret = vdev->fops->poll(filp, poll);
299 if (vdev->lock)
300 mutex_unlock(vdev->lock);
301 return ret;
302 }
303
v4l2_ioctl(struct file * filp,unsigned int cmd,unsigned long arg)304 static long v4l2_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
305 {
306 struct video_device *vdev = video_devdata(filp);
307 int ret = -ENODEV;
308
309 if (vdev->fops->unlocked_ioctl) {
310 if (vdev->lock && mutex_lock_interruptible(vdev->lock))
311 return -ERESTARTSYS;
312 if (video_is_registered(vdev))
313 ret = vdev->fops->unlocked_ioctl(filp, cmd, arg);
314 if (vdev->lock)
315 mutex_unlock(vdev->lock);
316 } else if (vdev->fops->ioctl) {
317 /* This code path is a replacement for the BKL. It is a major
318 * hack but it will have to do for those drivers that are not
319 * yet converted to use unlocked_ioctl.
320 *
321 * There are two options: if the driver implements struct
322 * v4l2_device, then the lock defined there is used to
323 * serialize the ioctls. Otherwise the v4l2 core lock defined
324 * below is used. This lock is really bad since it serializes
325 * completely independent devices.
326 *
327 * Both variants suffer from the same problem: if the driver
328 * sleeps, then it blocks all ioctls since the lock is still
329 * held. This is very common for VIDIOC_DQBUF since that
330 * normally waits for a frame to arrive. As a result any other
331 * ioctl calls will proceed very, very slowly since each call
332 * will have to wait for the VIDIOC_QBUF to finish. Things that
333 * should take 0.01s may now take 10-20 seconds.
334 *
335 * The workaround is to *not* take the lock for VIDIOC_DQBUF.
336 * This actually works OK for videobuf-based drivers, since
337 * videobuf will take its own internal lock.
338 */
339 static DEFINE_MUTEX(v4l2_ioctl_mutex);
340 struct mutex *m = vdev->v4l2_dev ?
341 &vdev->v4l2_dev->ioctl_lock : &v4l2_ioctl_mutex;
342
343 if (cmd != VIDIOC_DQBUF && mutex_lock_interruptible(m))
344 return -ERESTARTSYS;
345 if (video_is_registered(vdev))
346 ret = vdev->fops->ioctl(filp, cmd, arg);
347 if (cmd != VIDIOC_DQBUF)
348 mutex_unlock(m);
349 } else
350 ret = -ENOTTY;
351
352 return ret;
353 }
354
v4l2_mmap(struct file * filp,struct vm_area_struct * vm)355 static int v4l2_mmap(struct file *filp, struct vm_area_struct *vm)
356 {
357 struct video_device *vdev = video_devdata(filp);
358 int ret = -ENODEV;
359
360 if (!vdev->fops->mmap)
361 return ret;
362 if (vdev->lock && mutex_lock_interruptible(vdev->lock))
363 return -ERESTARTSYS;
364 if (video_is_registered(vdev))
365 ret = vdev->fops->mmap(filp, vm);
366 if (vdev->lock)
367 mutex_unlock(vdev->lock);
368 return ret;
369 }
370
371 /* Override for the open function */
v4l2_open(struct inode * inode,struct file * filp)372 static int v4l2_open(struct inode *inode, struct file *filp)
373 {
374 struct video_device *vdev;
375 #if defined(CONFIG_MEDIA_CONTROLLER)
376 struct media_entity *entity = NULL;
377 #endif
378 int ret = 0;
379
380 /* Check if the video device is available */
381 mutex_lock(&videodev_lock);
382 vdev = video_devdata(filp);
383 /* return ENODEV if the video device has already been removed. */
384 if (vdev == NULL || !video_is_registered(vdev)) {
385 mutex_unlock(&videodev_lock);
386 return -ENODEV;
387 }
388 /* and increase the device refcount */
389 video_get(vdev);
390 mutex_unlock(&videodev_lock);
391 #if defined(CONFIG_MEDIA_CONTROLLER)
392 if (vdev->v4l2_dev && vdev->v4l2_dev->mdev &&
393 vdev->vfl_type != VFL_TYPE_SUBDEV) {
394 entity = media_entity_get(&vdev->entity);
395 if (!entity) {
396 ret = -EBUSY;
397 video_put(vdev);
398 return ret;
399 }
400 }
401 #endif
402 if (vdev->fops->open) {
403 if (vdev->lock && mutex_lock_interruptible(vdev->lock)) {
404 ret = -ERESTARTSYS;
405 goto err;
406 }
407 if (video_is_registered(vdev))
408 ret = vdev->fops->open(filp);
409 else
410 ret = -ENODEV;
411 if (vdev->lock)
412 mutex_unlock(vdev->lock);
413 }
414
415 err:
416 /* decrease the refcount in case of an error */
417 if (ret) {
418 #if defined(CONFIG_MEDIA_CONTROLLER)
419 if (vdev->v4l2_dev && vdev->v4l2_dev->mdev &&
420 vdev->vfl_type != VFL_TYPE_SUBDEV)
421 media_entity_put(entity);
422 #endif
423 video_put(vdev);
424 }
425 return ret;
426 }
427
428 /* Override for the release function */
v4l2_release(struct inode * inode,struct file * filp)429 static int v4l2_release(struct inode *inode, struct file *filp)
430 {
431 struct video_device *vdev = video_devdata(filp);
432 int ret = 0;
433
434 if (vdev->fops->release) {
435 if (vdev->lock)
436 mutex_lock(vdev->lock);
437 vdev->fops->release(filp);
438 if (vdev->lock)
439 mutex_unlock(vdev->lock);
440 }
441 #if defined(CONFIG_MEDIA_CONTROLLER)
442 if (vdev->v4l2_dev && vdev->v4l2_dev->mdev &&
443 vdev->vfl_type != VFL_TYPE_SUBDEV)
444 media_entity_put(&vdev->entity);
445 #endif
446 /* decrease the refcount unconditionally since the release()
447 return value is ignored. */
448 video_put(vdev);
449 return ret;
450 }
451
452 static const struct file_operations v4l2_fops = {
453 .owner = THIS_MODULE,
454 .read = v4l2_read,
455 .write = v4l2_write,
456 .open = v4l2_open,
457 .mmap = v4l2_mmap,
458 .unlocked_ioctl = v4l2_ioctl,
459 #ifdef CONFIG_COMPAT
460 .compat_ioctl = v4l2_compat_ioctl32,
461 #endif
462 .release = v4l2_release,
463 .poll = v4l2_poll,
464 .llseek = no_llseek,
465 };
466
467 /**
468 * get_index - assign stream index number based on parent device
469 * @vdev: video_device to assign index number to, vdev->parent should be assigned
470 *
471 * Note that when this is called the new device has not yet been registered
472 * in the video_device array, but it was able to obtain a minor number.
473 *
474 * This means that we can always obtain a free stream index number since
475 * the worst case scenario is that there are VIDEO_NUM_DEVICES - 1 slots in
476 * use of the video_device array.
477 *
478 * Returns a free index number.
479 */
get_index(struct video_device * vdev)480 static int get_index(struct video_device *vdev)
481 {
482 /* This can be static since this function is called with the global
483 videodev_lock held. */
484 static DECLARE_BITMAP(used, VIDEO_NUM_DEVICES);
485 int i;
486
487 /* Some drivers do not set the parent. In that case always return 0. */
488 if (vdev->parent == NULL)
489 return 0;
490
491 bitmap_zero(used, VIDEO_NUM_DEVICES);
492
493 for (i = 0; i < VIDEO_NUM_DEVICES; i++) {
494 if (video_device[i] != NULL &&
495 video_device[i]->parent == vdev->parent) {
496 set_bit(video_device[i]->index, used);
497 }
498 }
499
500 return find_first_zero_bit(used, VIDEO_NUM_DEVICES);
501 }
502
503 /**
504 * __video_register_device - register video4linux devices
505 * @vdev: video device structure we want to register
506 * @type: type of device to register
507 * @nr: which device node number (0 == /dev/video0, 1 == /dev/video1, ...
508 * -1 == first free)
509 * @warn_if_nr_in_use: warn if the desired device node number
510 * was already in use and another number was chosen instead.
511 * @owner: module that owns the video device node
512 *
513 * The registration code assigns minor numbers and device node numbers
514 * based on the requested type and registers the new device node with
515 * the kernel.
516 *
517 * This function assumes that struct video_device was zeroed when it
518 * was allocated and does not contain any stale date.
519 *
520 * An error is returned if no free minor or device node number could be
521 * found, or if the registration of the device node failed.
522 *
523 * Zero is returned on success.
524 *
525 * Valid types are
526 *
527 * %VFL_TYPE_GRABBER - A frame grabber
528 *
529 * %VFL_TYPE_VBI - Vertical blank data (undecoded)
530 *
531 * %VFL_TYPE_RADIO - A radio card
532 *
533 * %VFL_TYPE_SUBDEV - A subdevice
534 */
__video_register_device(struct video_device * vdev,int type,int nr,int warn_if_nr_in_use,struct module * owner)535 int __video_register_device(struct video_device *vdev, int type, int nr,
536 int warn_if_nr_in_use, struct module *owner)
537 {
538 int i = 0;
539 int ret;
540 int minor_offset = 0;
541 int minor_cnt = VIDEO_NUM_DEVICES;
542 const char *name_base;
543
544 /* A minor value of -1 marks this video device as never
545 having been registered */
546 vdev->minor = -1;
547
548 /* the release callback MUST be present */
549 WARN_ON(!vdev->release);
550 if (!vdev->release)
551 return -EINVAL;
552
553 /* v4l2_fh support */
554 spin_lock_init(&vdev->fh_lock);
555 INIT_LIST_HEAD(&vdev->fh_list);
556
557 /* Part 1: check device type */
558 switch (type) {
559 case VFL_TYPE_GRABBER:
560 name_base = "video";
561 break;
562 case VFL_TYPE_VBI:
563 name_base = "vbi";
564 break;
565 case VFL_TYPE_RADIO:
566 name_base = "radio";
567 break;
568 case VFL_TYPE_SUBDEV:
569 name_base = "v4l-subdev";
570 break;
571 default:
572 printk(KERN_ERR "%s called with unknown type: %d\n",
573 __func__, type);
574 return -EINVAL;
575 }
576
577 vdev->vfl_type = type;
578 vdev->cdev = NULL;
579 if (vdev->v4l2_dev) {
580 if (vdev->v4l2_dev->dev)
581 vdev->parent = vdev->v4l2_dev->dev;
582 if (vdev->ctrl_handler == NULL)
583 vdev->ctrl_handler = vdev->v4l2_dev->ctrl_handler;
584 /* If the prio state pointer is NULL, then use the v4l2_device
585 prio state. */
586 if (vdev->prio == NULL)
587 vdev->prio = &vdev->v4l2_dev->prio;
588 }
589
590 /* Part 2: find a free minor, device node number and device index. */
591 #ifdef CONFIG_VIDEO_FIXED_MINOR_RANGES
592 /* Keep the ranges for the first four types for historical
593 * reasons.
594 * Newer devices (not yet in place) should use the range
595 * of 128-191 and just pick the first free minor there
596 * (new style). */
597 switch (type) {
598 case VFL_TYPE_GRABBER:
599 minor_offset = 0;
600 minor_cnt = 64;
601 break;
602 case VFL_TYPE_RADIO:
603 minor_offset = 64;
604 minor_cnt = 64;
605 break;
606 case VFL_TYPE_VBI:
607 minor_offset = 224;
608 minor_cnt = 32;
609 break;
610 default:
611 minor_offset = 128;
612 minor_cnt = 64;
613 break;
614 }
615 #endif
616
617 /* Pick a device node number */
618 mutex_lock(&videodev_lock);
619 nr = devnode_find(vdev, nr == -1 ? 0 : nr, minor_cnt);
620 if (nr == minor_cnt)
621 nr = devnode_find(vdev, 0, minor_cnt);
622 if (nr == minor_cnt) {
623 printk(KERN_ERR "could not get a free device node number\n");
624 mutex_unlock(&videodev_lock);
625 return -ENFILE;
626 }
627 #ifdef CONFIG_VIDEO_FIXED_MINOR_RANGES
628 /* 1-on-1 mapping of device node number to minor number */
629 i = nr;
630 #else
631 /* The device node number and minor numbers are independent, so
632 we just find the first free minor number. */
633 for (i = 0; i < VIDEO_NUM_DEVICES; i++)
634 if (video_device[i] == NULL)
635 break;
636 if (i == VIDEO_NUM_DEVICES) {
637 mutex_unlock(&videodev_lock);
638 printk(KERN_ERR "could not get a free minor\n");
639 return -ENFILE;
640 }
641 #endif
642 vdev->minor = i + minor_offset;
643 vdev->num = nr;
644 devnode_set(vdev);
645
646 /* Should not happen since we thought this minor was free */
647 WARN_ON(video_device[vdev->minor] != NULL);
648 vdev->index = get_index(vdev);
649 mutex_unlock(&videodev_lock);
650
651 /* Part 3: Initialize the character device */
652 vdev->cdev = cdev_alloc();
653 if (vdev->cdev == NULL) {
654 ret = -ENOMEM;
655 goto cleanup;
656 }
657 vdev->cdev->ops = &v4l2_fops;
658 vdev->cdev->owner = owner;
659 ret = cdev_add(vdev->cdev, MKDEV(VIDEO_MAJOR, vdev->minor), 1);
660 if (ret < 0) {
661 printk(KERN_ERR "%s: cdev_add failed\n", __func__);
662 kfree(vdev->cdev);
663 vdev->cdev = NULL;
664 goto cleanup;
665 }
666
667 /* Part 4: register the device with sysfs */
668 vdev->dev.class = &video_class;
669 vdev->dev.devt = MKDEV(VIDEO_MAJOR, vdev->minor);
670 if (vdev->parent)
671 vdev->dev.parent = vdev->parent;
672 dev_set_name(&vdev->dev, "%s%d", name_base, vdev->num);
673 ret = device_register(&vdev->dev);
674 if (ret < 0) {
675 printk(KERN_ERR "%s: device_register failed\n", __func__);
676 goto cleanup;
677 }
678 /* Register the release callback that will be called when the last
679 reference to the device goes away. */
680 vdev->dev.release = v4l2_device_release;
681
682 if (nr != -1 && nr != vdev->num && warn_if_nr_in_use)
683 printk(KERN_WARNING "%s: requested %s%d, got %s\n", __func__,
684 name_base, nr, video_device_node_name(vdev));
685
686 /* Increase v4l2_device refcount */
687 if (vdev->v4l2_dev)
688 v4l2_device_get(vdev->v4l2_dev);
689
690 #if defined(CONFIG_MEDIA_CONTROLLER)
691 /* Part 5: Register the entity. */
692 if (vdev->v4l2_dev && vdev->v4l2_dev->mdev &&
693 vdev->vfl_type != VFL_TYPE_SUBDEV) {
694 vdev->entity.type = MEDIA_ENT_T_DEVNODE_V4L;
695 vdev->entity.name = vdev->name;
696 vdev->entity.v4l.major = VIDEO_MAJOR;
697 vdev->entity.v4l.minor = vdev->minor;
698 ret = media_device_register_entity(vdev->v4l2_dev->mdev,
699 &vdev->entity);
700 if (ret < 0)
701 printk(KERN_WARNING
702 "%s: media_device_register_entity failed\n",
703 __func__);
704 }
705 #endif
706 /* Part 6: Activate this minor. The char device can now be used. */
707 set_bit(V4L2_FL_REGISTERED, &vdev->flags);
708 mutex_lock(&videodev_lock);
709 video_device[vdev->minor] = vdev;
710 mutex_unlock(&videodev_lock);
711
712 return 0;
713
714 cleanup:
715 mutex_lock(&videodev_lock);
716 if (vdev->cdev)
717 cdev_del(vdev->cdev);
718 devnode_clear(vdev);
719 mutex_unlock(&videodev_lock);
720 /* Mark this video device as never having been registered. */
721 vdev->minor = -1;
722 return ret;
723 }
724 EXPORT_SYMBOL(__video_register_device);
725
726 /**
727 * video_unregister_device - unregister a video4linux device
728 * @vdev: the device to unregister
729 *
730 * This unregisters the passed device. Future open calls will
731 * be met with errors.
732 */
video_unregister_device(struct video_device * vdev)733 void video_unregister_device(struct video_device *vdev)
734 {
735 /* Check if vdev was ever registered at all */
736 if (!vdev || !video_is_registered(vdev))
737 return;
738
739 #if defined(CONFIG_MEDIA_CONTROLLER)
740 if (vdev->v4l2_dev && vdev->v4l2_dev->mdev &&
741 vdev->vfl_type != VFL_TYPE_SUBDEV)
742 media_device_unregister_entity(&vdev->entity);
743 #endif
744
745 mutex_lock(&videodev_lock);
746 /* This must be in a critical section to prevent a race with v4l2_open.
747 * Once this bit has been cleared video_get may never be called again.
748 */
749 clear_bit(V4L2_FL_REGISTERED, &vdev->flags);
750 mutex_unlock(&videodev_lock);
751 device_unregister(&vdev->dev);
752 }
753 EXPORT_SYMBOL(video_unregister_device);
754
755 /*
756 * Initialise video for linux
757 */
videodev_init(void)758 static int __init videodev_init(void)
759 {
760 dev_t dev = MKDEV(VIDEO_MAJOR, 0);
761 int ret;
762
763 printk(KERN_INFO "Linux video capture interface: v2.00\n");
764 ret = register_chrdev_region(dev, VIDEO_NUM_DEVICES, VIDEO_NAME);
765 if (ret < 0) {
766 printk(KERN_WARNING "videodev: unable to get major %d\n",
767 VIDEO_MAJOR);
768 return ret;
769 }
770
771 ret = class_register(&video_class);
772 if (ret < 0) {
773 unregister_chrdev_region(dev, VIDEO_NUM_DEVICES);
774 printk(KERN_WARNING "video_dev: class_register failed\n");
775 return -EIO;
776 }
777
778 return 0;
779 }
780
videodev_exit(void)781 static void __exit videodev_exit(void)
782 {
783 dev_t dev = MKDEV(VIDEO_MAJOR, 0);
784
785 class_unregister(&video_class);
786 unregister_chrdev_region(dev, VIDEO_NUM_DEVICES);
787 }
788
789 module_init(videodev_init)
790 module_exit(videodev_exit)
791
792 MODULE_AUTHOR("Alan Cox, Mauro Carvalho Chehab <mchehab@infradead.org>");
793 MODULE_DESCRIPTION("Device registrar for Video4Linux drivers v2");
794 MODULE_LICENSE("GPL");
795 MODULE_ALIAS_CHARDEV_MAJOR(VIDEO_MAJOR);
796
797
798 /*
799 * Local variables:
800 * c-basic-offset: 8
801 * End:
802 */
803