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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 
30 #include <media/v4l2-common.h>
31 #include <media/v4l2-device.h>
32 #include <media/v4l2-ioctl.h>
33 
34 #define VIDEO_NUM_DEVICES	256
35 #define VIDEO_NAME              "video4linux"
36 
37 /*
38  *	sysfs stuff
39  */
40 
index_show(struct device * cd,struct device_attribute * attr,char * buf)41 static ssize_t index_show(struct device *cd,
42 			  struct device_attribute *attr, char *buf)
43 {
44 	struct video_device *vdev = to_video_device(cd);
45 
46 	return sprintf(buf, "%i\n", vdev->index);
47 }
48 static DEVICE_ATTR_RO(index);
49 
dev_debug_show(struct device * cd,struct device_attribute * attr,char * buf)50 static ssize_t dev_debug_show(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, "%i\n", vdev->dev_debug);
56 }
57 
dev_debug_store(struct device * cd,struct device_attribute * attr,const char * buf,size_t len)58 static ssize_t dev_debug_store(struct device *cd, struct device_attribute *attr,
59 			  const char *buf, size_t len)
60 {
61 	struct video_device *vdev = to_video_device(cd);
62 	int res = 0;
63 	u16 value;
64 
65 	res = kstrtou16(buf, 0, &value);
66 	if (res)
67 		return res;
68 
69 	vdev->dev_debug = value;
70 	return len;
71 }
72 static DEVICE_ATTR_RW(dev_debug);
73 
name_show(struct device * cd,struct device_attribute * attr,char * buf)74 static ssize_t name_show(struct device *cd,
75 			 struct device_attribute *attr, char *buf)
76 {
77 	struct video_device *vdev = to_video_device(cd);
78 
79 	return sprintf(buf, "%.*s\n", (int)sizeof(vdev->name), vdev->name);
80 }
81 static DEVICE_ATTR_RO(name);
82 
83 static struct attribute *video_device_attrs[] = {
84 	&dev_attr_name.attr,
85 	&dev_attr_dev_debug.attr,
86 	&dev_attr_index.attr,
87 	NULL,
88 };
89 ATTRIBUTE_GROUPS(video_device);
90 
91 /*
92  *	Active devices
93  */
94 static struct video_device *video_device[VIDEO_NUM_DEVICES];
95 static DEFINE_MUTEX(videodev_lock);
96 static DECLARE_BITMAP(devnode_nums[VFL_TYPE_MAX], VIDEO_NUM_DEVICES);
97 
98 /* Device node utility functions */
99 
100 /* Note: these utility functions all assume that vfl_type is in the range
101    [0, VFL_TYPE_MAX-1]. */
102 
103 #ifdef CONFIG_VIDEO_FIXED_MINOR_RANGES
104 /* Return the bitmap corresponding to vfl_type. */
devnode_bits(int vfl_type)105 static inline unsigned long *devnode_bits(int vfl_type)
106 {
107 	/* Any types not assigned to fixed minor ranges must be mapped to
108 	   one single bitmap for the purposes of finding a free node number
109 	   since all those unassigned types use the same minor range. */
110 	int idx = (vfl_type > VFL_TYPE_RADIO) ? VFL_TYPE_MAX - 1 : vfl_type;
111 
112 	return devnode_nums[idx];
113 }
114 #else
115 /* Return the bitmap corresponding to vfl_type. */
devnode_bits(int vfl_type)116 static inline unsigned long *devnode_bits(int vfl_type)
117 {
118 	return devnode_nums[vfl_type];
119 }
120 #endif
121 
122 /* Mark device node number vdev->num as used */
devnode_set(struct video_device * vdev)123 static inline void devnode_set(struct video_device *vdev)
124 {
125 	set_bit(vdev->num, devnode_bits(vdev->vfl_type));
126 }
127 
128 /* Mark device node number vdev->num as unused */
devnode_clear(struct video_device * vdev)129 static inline void devnode_clear(struct video_device *vdev)
130 {
131 	clear_bit(vdev->num, devnode_bits(vdev->vfl_type));
132 }
133 
134 /* Try to find a free device node number in the range [from, to> */
devnode_find(struct video_device * vdev,int from,int to)135 static inline int devnode_find(struct video_device *vdev, int from, int to)
136 {
137 	return find_next_zero_bit(devnode_bits(vdev->vfl_type), to, from);
138 }
139 
video_device_alloc(void)140 struct video_device *video_device_alloc(void)
141 {
142 	return kzalloc(sizeof(struct video_device), GFP_KERNEL);
143 }
144 EXPORT_SYMBOL(video_device_alloc);
145 
video_device_release(struct video_device * vdev)146 void video_device_release(struct video_device *vdev)
147 {
148 	kfree(vdev);
149 }
150 EXPORT_SYMBOL(video_device_release);
151 
video_device_release_empty(struct video_device * vdev)152 void video_device_release_empty(struct video_device *vdev)
153 {
154 	/* Do nothing */
155 	/* Only valid when the video_device struct is a static. */
156 }
157 EXPORT_SYMBOL(video_device_release_empty);
158 
video_get(struct video_device * vdev)159 static inline void video_get(struct video_device *vdev)
160 {
161 	get_device(&vdev->dev);
162 }
163 
video_put(struct video_device * vdev)164 static inline void video_put(struct video_device *vdev)
165 {
166 	put_device(&vdev->dev);
167 }
168 
169 /* Called when the last user of the video device exits. */
v4l2_device_release(struct device * cd)170 static void v4l2_device_release(struct device *cd)
171 {
172 	struct video_device *vdev = to_video_device(cd);
173 	struct v4l2_device *v4l2_dev = vdev->v4l2_dev;
174 
175 	mutex_lock(&videodev_lock);
176 	if (WARN_ON(video_device[vdev->minor] != vdev)) {
177 		/* should not happen */
178 		mutex_unlock(&videodev_lock);
179 		return;
180 	}
181 
182 	/* Free up this device for reuse */
183 	video_device[vdev->minor] = NULL;
184 
185 	/* Delete the cdev on this minor as well */
186 	cdev_del(vdev->cdev);
187 	/* Just in case some driver tries to access this from
188 	   the release() callback. */
189 	vdev->cdev = NULL;
190 
191 	/* Mark device node number as free */
192 	devnode_clear(vdev);
193 
194 	mutex_unlock(&videodev_lock);
195 
196 #if defined(CONFIG_MEDIA_CONTROLLER)
197 	if (v4l2_dev->mdev) {
198 		/* Remove interfaces and interface links */
199 		media_devnode_remove(vdev->intf_devnode);
200 		if (vdev->entity.function != MEDIA_ENT_F_UNKNOWN)
201 			media_device_unregister_entity(&vdev->entity);
202 	}
203 #endif
204 
205 	/* Do not call v4l2_device_put if there is no release callback set.
206 	 * Drivers that have no v4l2_device release callback might free the
207 	 * v4l2_dev instance in the video_device release callback below, so we
208 	 * must perform this check here.
209 	 *
210 	 * TODO: In the long run all drivers that use v4l2_device should use the
211 	 * v4l2_device release callback. This check will then be unnecessary.
212 	 */
213 	if (v4l2_dev->release == NULL)
214 		v4l2_dev = NULL;
215 
216 	/* Release video_device and perform other
217 	   cleanups as needed. */
218 	vdev->release(vdev);
219 
220 	/* Decrease v4l2_device refcount */
221 	if (v4l2_dev)
222 		v4l2_device_put(v4l2_dev);
223 }
224 
225 static struct class video_class = {
226 	.name = VIDEO_NAME,
227 	.dev_groups = video_device_groups,
228 };
229 
video_devdata(struct file * file)230 struct video_device *video_devdata(struct file *file)
231 {
232 	return video_device[iminor(file_inode(file))];
233 }
234 EXPORT_SYMBOL(video_devdata);
235 
236 
237 /* Priority handling */
238 
prio_is_valid(enum v4l2_priority prio)239 static inline bool prio_is_valid(enum v4l2_priority prio)
240 {
241 	return prio == V4L2_PRIORITY_BACKGROUND ||
242 	       prio == V4L2_PRIORITY_INTERACTIVE ||
243 	       prio == V4L2_PRIORITY_RECORD;
244 }
245 
v4l2_prio_init(struct v4l2_prio_state * global)246 void v4l2_prio_init(struct v4l2_prio_state *global)
247 {
248 	memset(global, 0, sizeof(*global));
249 }
250 EXPORT_SYMBOL(v4l2_prio_init);
251 
v4l2_prio_change(struct v4l2_prio_state * global,enum v4l2_priority * local,enum v4l2_priority new)252 int v4l2_prio_change(struct v4l2_prio_state *global, enum v4l2_priority *local,
253 		     enum v4l2_priority new)
254 {
255 	if (!prio_is_valid(new))
256 		return -EINVAL;
257 	if (*local == new)
258 		return 0;
259 
260 	atomic_inc(&global->prios[new]);
261 	if (prio_is_valid(*local))
262 		atomic_dec(&global->prios[*local]);
263 	*local = new;
264 	return 0;
265 }
266 EXPORT_SYMBOL(v4l2_prio_change);
267 
v4l2_prio_open(struct v4l2_prio_state * global,enum v4l2_priority * local)268 void v4l2_prio_open(struct v4l2_prio_state *global, enum v4l2_priority *local)
269 {
270 	v4l2_prio_change(global, local, V4L2_PRIORITY_DEFAULT);
271 }
272 EXPORT_SYMBOL(v4l2_prio_open);
273 
v4l2_prio_close(struct v4l2_prio_state * global,enum v4l2_priority local)274 void v4l2_prio_close(struct v4l2_prio_state *global, enum v4l2_priority local)
275 {
276 	if (prio_is_valid(local))
277 		atomic_dec(&global->prios[local]);
278 }
279 EXPORT_SYMBOL(v4l2_prio_close);
280 
v4l2_prio_max(struct v4l2_prio_state * global)281 enum v4l2_priority v4l2_prio_max(struct v4l2_prio_state *global)
282 {
283 	if (atomic_read(&global->prios[V4L2_PRIORITY_RECORD]) > 0)
284 		return V4L2_PRIORITY_RECORD;
285 	if (atomic_read(&global->prios[V4L2_PRIORITY_INTERACTIVE]) > 0)
286 		return V4L2_PRIORITY_INTERACTIVE;
287 	if (atomic_read(&global->prios[V4L2_PRIORITY_BACKGROUND]) > 0)
288 		return V4L2_PRIORITY_BACKGROUND;
289 	return V4L2_PRIORITY_UNSET;
290 }
291 EXPORT_SYMBOL(v4l2_prio_max);
292 
v4l2_prio_check(struct v4l2_prio_state * global,enum v4l2_priority local)293 int v4l2_prio_check(struct v4l2_prio_state *global, enum v4l2_priority local)
294 {
295 	return (local < v4l2_prio_max(global)) ? -EBUSY : 0;
296 }
297 EXPORT_SYMBOL(v4l2_prio_check);
298 
299 
v4l2_read(struct file * filp,char __user * buf,size_t sz,loff_t * off)300 static ssize_t v4l2_read(struct file *filp, char __user *buf,
301 		size_t sz, loff_t *off)
302 {
303 	struct video_device *vdev = video_devdata(filp);
304 	int ret = -ENODEV;
305 
306 	if (!vdev->fops->read)
307 		return -EINVAL;
308 	if (video_is_registered(vdev))
309 		ret = vdev->fops->read(filp, buf, sz, off);
310 	if ((vdev->dev_debug & V4L2_DEV_DEBUG_FOP) &&
311 	    (vdev->dev_debug & V4L2_DEV_DEBUG_STREAMING))
312 		printk(KERN_DEBUG "%s: read: %zd (%d)\n",
313 			video_device_node_name(vdev), sz, ret);
314 	return ret;
315 }
316 
v4l2_write(struct file * filp,const char __user * buf,size_t sz,loff_t * off)317 static ssize_t v4l2_write(struct file *filp, const char __user *buf,
318 		size_t sz, loff_t *off)
319 {
320 	struct video_device *vdev = video_devdata(filp);
321 	int ret = -ENODEV;
322 
323 	if (!vdev->fops->write)
324 		return -EINVAL;
325 	if (video_is_registered(vdev))
326 		ret = vdev->fops->write(filp, buf, sz, off);
327 	if ((vdev->dev_debug & V4L2_DEV_DEBUG_FOP) &&
328 	    (vdev->dev_debug & V4L2_DEV_DEBUG_STREAMING))
329 		printk(KERN_DEBUG "%s: write: %zd (%d)\n",
330 			video_device_node_name(vdev), sz, ret);
331 	return ret;
332 }
333 
v4l2_poll(struct file * filp,struct poll_table_struct * poll)334 static unsigned int v4l2_poll(struct file *filp, struct poll_table_struct *poll)
335 {
336 	struct video_device *vdev = video_devdata(filp);
337 	unsigned int res = POLLERR | POLLHUP;
338 
339 	if (!vdev->fops->poll)
340 		return DEFAULT_POLLMASK;
341 	if (video_is_registered(vdev))
342 		res = vdev->fops->poll(filp, poll);
343 	if (vdev->dev_debug & V4L2_DEV_DEBUG_POLL)
344 		printk(KERN_DEBUG "%s: poll: %08x\n",
345 			video_device_node_name(vdev), res);
346 	return res;
347 }
348 
v4l2_ioctl(struct file * filp,unsigned int cmd,unsigned long arg)349 static long v4l2_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
350 {
351 	struct video_device *vdev = video_devdata(filp);
352 	int ret = -ENODEV;
353 
354 	if (vdev->fops->unlocked_ioctl) {
355 		struct mutex *lock = v4l2_ioctl_get_lock(vdev, cmd);
356 
357 		if (lock && mutex_lock_interruptible(lock))
358 			return -ERESTARTSYS;
359 		if (video_is_registered(vdev))
360 			ret = vdev->fops->unlocked_ioctl(filp, cmd, arg);
361 		if (lock)
362 			mutex_unlock(lock);
363 	} else
364 		ret = -ENOTTY;
365 
366 	return ret;
367 }
368 
369 #ifdef CONFIG_MMU
370 #define v4l2_get_unmapped_area NULL
371 #else
v4l2_get_unmapped_area(struct file * filp,unsigned long addr,unsigned long len,unsigned long pgoff,unsigned long flags)372 static unsigned long v4l2_get_unmapped_area(struct file *filp,
373 		unsigned long addr, unsigned long len, unsigned long pgoff,
374 		unsigned long flags)
375 {
376 	struct video_device *vdev = video_devdata(filp);
377 	int ret;
378 
379 	if (!vdev->fops->get_unmapped_area)
380 		return -ENOSYS;
381 	if (!video_is_registered(vdev))
382 		return -ENODEV;
383 	ret = vdev->fops->get_unmapped_area(filp, addr, len, pgoff, flags);
384 	if (vdev->dev_debug & V4L2_DEV_DEBUG_FOP)
385 		printk(KERN_DEBUG "%s: get_unmapped_area (%d)\n",
386 			video_device_node_name(vdev), ret);
387 	return ret;
388 }
389 #endif
390 
v4l2_mmap(struct file * filp,struct vm_area_struct * vm)391 static int v4l2_mmap(struct file *filp, struct vm_area_struct *vm)
392 {
393 	struct video_device *vdev = video_devdata(filp);
394 	int ret = -ENODEV;
395 
396 	if (!vdev->fops->mmap)
397 		return -ENODEV;
398 	if (video_is_registered(vdev))
399 		ret = vdev->fops->mmap(filp, vm);
400 	if (vdev->dev_debug & V4L2_DEV_DEBUG_FOP)
401 		printk(KERN_DEBUG "%s: mmap (%d)\n",
402 			video_device_node_name(vdev), ret);
403 	return ret;
404 }
405 
406 /* Override for the open function */
v4l2_open(struct inode * inode,struct file * filp)407 static int v4l2_open(struct inode *inode, struct file *filp)
408 {
409 	struct video_device *vdev;
410 	int ret = 0;
411 
412 	/* Check if the video device is available */
413 	mutex_lock(&videodev_lock);
414 	vdev = video_devdata(filp);
415 	/* return ENODEV if the video device has already been removed. */
416 	if (vdev == NULL || !video_is_registered(vdev)) {
417 		mutex_unlock(&videodev_lock);
418 		return -ENODEV;
419 	}
420 	/* and increase the device refcount */
421 	video_get(vdev);
422 	mutex_unlock(&videodev_lock);
423 	if (vdev->fops->open) {
424 		if (video_is_registered(vdev))
425 			ret = vdev->fops->open(filp);
426 		else
427 			ret = -ENODEV;
428 	}
429 
430 	if (vdev->dev_debug & V4L2_DEV_DEBUG_FOP)
431 		printk(KERN_DEBUG "%s: open (%d)\n",
432 			video_device_node_name(vdev), ret);
433 	/* decrease the refcount in case of an error */
434 	if (ret)
435 		video_put(vdev);
436 	return ret;
437 }
438 
439 /* Override for the release function */
v4l2_release(struct inode * inode,struct file * filp)440 static int v4l2_release(struct inode *inode, struct file *filp)
441 {
442 	struct video_device *vdev = video_devdata(filp);
443 	int ret = 0;
444 
445 	if (vdev->fops->release)
446 		ret = vdev->fops->release(filp);
447 	if (vdev->dev_debug & V4L2_DEV_DEBUG_FOP)
448 		printk(KERN_DEBUG "%s: release\n",
449 			video_device_node_name(vdev));
450 
451 	/* decrease the refcount unconditionally since the release()
452 	   return value is ignored. */
453 	video_put(vdev);
454 	return ret;
455 }
456 
457 static const struct file_operations v4l2_fops = {
458 	.owner = THIS_MODULE,
459 	.read = v4l2_read,
460 	.write = v4l2_write,
461 	.open = v4l2_open,
462 	.get_unmapped_area = v4l2_get_unmapped_area,
463 	.mmap = v4l2_mmap,
464 	.unlocked_ioctl = v4l2_ioctl,
465 #ifdef CONFIG_COMPAT
466 	.compat_ioctl = v4l2_compat_ioctl32,
467 #endif
468 	.release = v4l2_release,
469 	.poll = v4l2_poll,
470 	.llseek = no_llseek,
471 };
472 
473 /**
474  * get_index - assign stream index number based on v4l2_dev
475  * @vdev: video_device to assign index number to, vdev->v4l2_dev should be assigned
476  *
477  * Note that when this is called the new device has not yet been registered
478  * in the video_device array, but it was able to obtain a minor number.
479  *
480  * This means that we can always obtain a free stream index number since
481  * the worst case scenario is that there are VIDEO_NUM_DEVICES - 1 slots in
482  * use of the video_device array.
483  *
484  * Returns a free index number.
485  */
get_index(struct video_device * vdev)486 static int get_index(struct video_device *vdev)
487 {
488 	/* This can be static since this function is called with the global
489 	   videodev_lock held. */
490 	static DECLARE_BITMAP(used, VIDEO_NUM_DEVICES);
491 	int i;
492 
493 	bitmap_zero(used, VIDEO_NUM_DEVICES);
494 
495 	for (i = 0; i < VIDEO_NUM_DEVICES; i++) {
496 		if (video_device[i] != NULL &&
497 		    video_device[i]->v4l2_dev == vdev->v4l2_dev) {
498 			set_bit(video_device[i]->index, used);
499 		}
500 	}
501 
502 	return find_first_zero_bit(used, VIDEO_NUM_DEVICES);
503 }
504 
505 #define SET_VALID_IOCTL(ops, cmd, op)			\
506 	if (ops->op)					\
507 		set_bit(_IOC_NR(cmd), valid_ioctls)
508 
509 /* This determines which ioctls are actually implemented in the driver.
510    It's a one-time thing which simplifies video_ioctl2 as it can just do
511    a bit test.
512 
513    Note that drivers can override this by setting bits to 1 in
514    vdev->valid_ioctls. If an ioctl is marked as 1 when this function is
515    called, then that ioctl will actually be marked as unimplemented.
516 
517    It does that by first setting up the local valid_ioctls bitmap, and
518    at the end do a:
519 
520    vdev->valid_ioctls = valid_ioctls & ~(vdev->valid_ioctls)
521  */
determine_valid_ioctls(struct video_device * vdev)522 static void determine_valid_ioctls(struct video_device *vdev)
523 {
524 	DECLARE_BITMAP(valid_ioctls, BASE_VIDIOC_PRIVATE);
525 	const struct v4l2_ioctl_ops *ops = vdev->ioctl_ops;
526 	bool is_vid = vdev->vfl_type == VFL_TYPE_GRABBER;
527 	bool is_vbi = vdev->vfl_type == VFL_TYPE_VBI;
528 	bool is_radio = vdev->vfl_type == VFL_TYPE_RADIO;
529 	bool is_sdr = vdev->vfl_type == VFL_TYPE_SDR;
530 	bool is_tch = vdev->vfl_type == VFL_TYPE_TOUCH;
531 	bool is_rx = vdev->vfl_dir != VFL_DIR_TX;
532 	bool is_tx = vdev->vfl_dir != VFL_DIR_RX;
533 
534 	bitmap_zero(valid_ioctls, BASE_VIDIOC_PRIVATE);
535 
536 	/* vfl_type and vfl_dir independent ioctls */
537 
538 	SET_VALID_IOCTL(ops, VIDIOC_QUERYCAP, vidioc_querycap);
539 	set_bit(_IOC_NR(VIDIOC_G_PRIORITY), valid_ioctls);
540 	set_bit(_IOC_NR(VIDIOC_S_PRIORITY), valid_ioctls);
541 
542 	/* Note: the control handler can also be passed through the filehandle,
543 	   and that can't be tested here. If the bit for these control ioctls
544 	   is set, then the ioctl is valid. But if it is 0, then it can still
545 	   be valid if the filehandle passed the control handler. */
546 	if (vdev->ctrl_handler || ops->vidioc_queryctrl)
547 		set_bit(_IOC_NR(VIDIOC_QUERYCTRL), valid_ioctls);
548 	if (vdev->ctrl_handler || ops->vidioc_query_ext_ctrl)
549 		set_bit(_IOC_NR(VIDIOC_QUERY_EXT_CTRL), valid_ioctls);
550 	if (vdev->ctrl_handler || ops->vidioc_g_ctrl || ops->vidioc_g_ext_ctrls)
551 		set_bit(_IOC_NR(VIDIOC_G_CTRL), valid_ioctls);
552 	if (vdev->ctrl_handler || ops->vidioc_s_ctrl || ops->vidioc_s_ext_ctrls)
553 		set_bit(_IOC_NR(VIDIOC_S_CTRL), valid_ioctls);
554 	if (vdev->ctrl_handler || ops->vidioc_g_ext_ctrls)
555 		set_bit(_IOC_NR(VIDIOC_G_EXT_CTRLS), valid_ioctls);
556 	if (vdev->ctrl_handler || ops->vidioc_s_ext_ctrls)
557 		set_bit(_IOC_NR(VIDIOC_S_EXT_CTRLS), valid_ioctls);
558 	if (vdev->ctrl_handler || ops->vidioc_try_ext_ctrls)
559 		set_bit(_IOC_NR(VIDIOC_TRY_EXT_CTRLS), valid_ioctls);
560 	if (vdev->ctrl_handler || ops->vidioc_querymenu)
561 		set_bit(_IOC_NR(VIDIOC_QUERYMENU), valid_ioctls);
562 	SET_VALID_IOCTL(ops, VIDIOC_G_FREQUENCY, vidioc_g_frequency);
563 	SET_VALID_IOCTL(ops, VIDIOC_S_FREQUENCY, vidioc_s_frequency);
564 	SET_VALID_IOCTL(ops, VIDIOC_LOG_STATUS, vidioc_log_status);
565 #ifdef CONFIG_VIDEO_ADV_DEBUG
566 	set_bit(_IOC_NR(VIDIOC_DBG_G_CHIP_INFO), valid_ioctls);
567 	set_bit(_IOC_NR(VIDIOC_DBG_G_REGISTER), valid_ioctls);
568 	set_bit(_IOC_NR(VIDIOC_DBG_S_REGISTER), valid_ioctls);
569 #endif
570 	/* yes, really vidioc_subscribe_event */
571 	SET_VALID_IOCTL(ops, VIDIOC_DQEVENT, vidioc_subscribe_event);
572 	SET_VALID_IOCTL(ops, VIDIOC_SUBSCRIBE_EVENT, vidioc_subscribe_event);
573 	SET_VALID_IOCTL(ops, VIDIOC_UNSUBSCRIBE_EVENT, vidioc_unsubscribe_event);
574 	if (ops->vidioc_enum_freq_bands || ops->vidioc_g_tuner || ops->vidioc_g_modulator)
575 		set_bit(_IOC_NR(VIDIOC_ENUM_FREQ_BANDS), valid_ioctls);
576 
577 	if (is_vid || is_tch) {
578 		/* video specific ioctls */
579 		if ((is_rx && (ops->vidioc_enum_fmt_vid_cap ||
580 			       ops->vidioc_enum_fmt_vid_cap_mplane ||
581 			       ops->vidioc_enum_fmt_vid_overlay)) ||
582 		    (is_tx && (ops->vidioc_enum_fmt_vid_out ||
583 			       ops->vidioc_enum_fmt_vid_out_mplane)))
584 			set_bit(_IOC_NR(VIDIOC_ENUM_FMT), valid_ioctls);
585 		if ((is_rx && (ops->vidioc_g_fmt_vid_cap ||
586 			       ops->vidioc_g_fmt_vid_cap_mplane ||
587 			       ops->vidioc_g_fmt_vid_overlay)) ||
588 		    (is_tx && (ops->vidioc_g_fmt_vid_out ||
589 			       ops->vidioc_g_fmt_vid_out_mplane ||
590 			       ops->vidioc_g_fmt_vid_out_overlay)))
591 			 set_bit(_IOC_NR(VIDIOC_G_FMT), valid_ioctls);
592 		if ((is_rx && (ops->vidioc_s_fmt_vid_cap ||
593 			       ops->vidioc_s_fmt_vid_cap_mplane ||
594 			       ops->vidioc_s_fmt_vid_overlay)) ||
595 		    (is_tx && (ops->vidioc_s_fmt_vid_out ||
596 			       ops->vidioc_s_fmt_vid_out_mplane ||
597 			       ops->vidioc_s_fmt_vid_out_overlay)))
598 			 set_bit(_IOC_NR(VIDIOC_S_FMT), valid_ioctls);
599 		if ((is_rx && (ops->vidioc_try_fmt_vid_cap ||
600 			       ops->vidioc_try_fmt_vid_cap_mplane ||
601 			       ops->vidioc_try_fmt_vid_overlay)) ||
602 		    (is_tx && (ops->vidioc_try_fmt_vid_out ||
603 			       ops->vidioc_try_fmt_vid_out_mplane ||
604 			       ops->vidioc_try_fmt_vid_out_overlay)))
605 			 set_bit(_IOC_NR(VIDIOC_TRY_FMT), valid_ioctls);
606 		SET_VALID_IOCTL(ops, VIDIOC_OVERLAY, vidioc_overlay);
607 		SET_VALID_IOCTL(ops, VIDIOC_G_FBUF, vidioc_g_fbuf);
608 		SET_VALID_IOCTL(ops, VIDIOC_S_FBUF, vidioc_s_fbuf);
609 		SET_VALID_IOCTL(ops, VIDIOC_G_JPEGCOMP, vidioc_g_jpegcomp);
610 		SET_VALID_IOCTL(ops, VIDIOC_S_JPEGCOMP, vidioc_s_jpegcomp);
611 		SET_VALID_IOCTL(ops, VIDIOC_G_ENC_INDEX, vidioc_g_enc_index);
612 		SET_VALID_IOCTL(ops, VIDIOC_ENCODER_CMD, vidioc_encoder_cmd);
613 		SET_VALID_IOCTL(ops, VIDIOC_TRY_ENCODER_CMD, vidioc_try_encoder_cmd);
614 		SET_VALID_IOCTL(ops, VIDIOC_DECODER_CMD, vidioc_decoder_cmd);
615 		SET_VALID_IOCTL(ops, VIDIOC_TRY_DECODER_CMD, vidioc_try_decoder_cmd);
616 		SET_VALID_IOCTL(ops, VIDIOC_ENUM_FRAMESIZES, vidioc_enum_framesizes);
617 		SET_VALID_IOCTL(ops, VIDIOC_ENUM_FRAMEINTERVALS, vidioc_enum_frameintervals);
618 		if (ops->vidioc_g_crop || ops->vidioc_g_selection)
619 			set_bit(_IOC_NR(VIDIOC_G_CROP), valid_ioctls);
620 		if (ops->vidioc_s_crop || ops->vidioc_s_selection)
621 			set_bit(_IOC_NR(VIDIOC_S_CROP), valid_ioctls);
622 		SET_VALID_IOCTL(ops, VIDIOC_G_SELECTION, vidioc_g_selection);
623 		SET_VALID_IOCTL(ops, VIDIOC_S_SELECTION, vidioc_s_selection);
624 		if (ops->vidioc_cropcap || ops->vidioc_g_selection)
625 			set_bit(_IOC_NR(VIDIOC_CROPCAP), valid_ioctls);
626 	} else if (is_vbi) {
627 		/* vbi specific ioctls */
628 		if ((is_rx && (ops->vidioc_g_fmt_vbi_cap ||
629 			       ops->vidioc_g_fmt_sliced_vbi_cap)) ||
630 		    (is_tx && (ops->vidioc_g_fmt_vbi_out ||
631 			       ops->vidioc_g_fmt_sliced_vbi_out)))
632 			set_bit(_IOC_NR(VIDIOC_G_FMT), valid_ioctls);
633 		if ((is_rx && (ops->vidioc_s_fmt_vbi_cap ||
634 			       ops->vidioc_s_fmt_sliced_vbi_cap)) ||
635 		    (is_tx && (ops->vidioc_s_fmt_vbi_out ||
636 			       ops->vidioc_s_fmt_sliced_vbi_out)))
637 			set_bit(_IOC_NR(VIDIOC_S_FMT), valid_ioctls);
638 		if ((is_rx && (ops->vidioc_try_fmt_vbi_cap ||
639 			       ops->vidioc_try_fmt_sliced_vbi_cap)) ||
640 		    (is_tx && (ops->vidioc_try_fmt_vbi_out ||
641 			       ops->vidioc_try_fmt_sliced_vbi_out)))
642 			set_bit(_IOC_NR(VIDIOC_TRY_FMT), valid_ioctls);
643 		SET_VALID_IOCTL(ops, VIDIOC_G_SLICED_VBI_CAP, vidioc_g_sliced_vbi_cap);
644 	} else if (is_sdr && is_rx) {
645 		/* SDR receiver specific ioctls */
646 		if (ops->vidioc_enum_fmt_sdr_cap)
647 			set_bit(_IOC_NR(VIDIOC_ENUM_FMT), valid_ioctls);
648 		if (ops->vidioc_g_fmt_sdr_cap)
649 			set_bit(_IOC_NR(VIDIOC_G_FMT), valid_ioctls);
650 		if (ops->vidioc_s_fmt_sdr_cap)
651 			set_bit(_IOC_NR(VIDIOC_S_FMT), valid_ioctls);
652 		if (ops->vidioc_try_fmt_sdr_cap)
653 			set_bit(_IOC_NR(VIDIOC_TRY_FMT), valid_ioctls);
654 	} else if (is_sdr && is_tx) {
655 		/* SDR transmitter specific ioctls */
656 		if (ops->vidioc_enum_fmt_sdr_out)
657 			set_bit(_IOC_NR(VIDIOC_ENUM_FMT), valid_ioctls);
658 		if (ops->vidioc_g_fmt_sdr_out)
659 			set_bit(_IOC_NR(VIDIOC_G_FMT), valid_ioctls);
660 		if (ops->vidioc_s_fmt_sdr_out)
661 			set_bit(_IOC_NR(VIDIOC_S_FMT), valid_ioctls);
662 		if (ops->vidioc_try_fmt_sdr_out)
663 			set_bit(_IOC_NR(VIDIOC_TRY_FMT), valid_ioctls);
664 	}
665 
666 	if (is_vid || is_vbi || is_sdr || is_tch) {
667 		/* ioctls valid for video, vbi or sdr */
668 		SET_VALID_IOCTL(ops, VIDIOC_REQBUFS, vidioc_reqbufs);
669 		SET_VALID_IOCTL(ops, VIDIOC_QUERYBUF, vidioc_querybuf);
670 		SET_VALID_IOCTL(ops, VIDIOC_QBUF, vidioc_qbuf);
671 		SET_VALID_IOCTL(ops, VIDIOC_EXPBUF, vidioc_expbuf);
672 		SET_VALID_IOCTL(ops, VIDIOC_DQBUF, vidioc_dqbuf);
673 		SET_VALID_IOCTL(ops, VIDIOC_CREATE_BUFS, vidioc_create_bufs);
674 		SET_VALID_IOCTL(ops, VIDIOC_PREPARE_BUF, vidioc_prepare_buf);
675 		SET_VALID_IOCTL(ops, VIDIOC_STREAMON, vidioc_streamon);
676 		SET_VALID_IOCTL(ops, VIDIOC_STREAMOFF, vidioc_streamoff);
677 	}
678 
679 	if (is_vid || is_vbi || is_tch) {
680 		/* ioctls valid for video or vbi */
681 		if (ops->vidioc_s_std)
682 			set_bit(_IOC_NR(VIDIOC_ENUMSTD), valid_ioctls);
683 		SET_VALID_IOCTL(ops, VIDIOC_S_STD, vidioc_s_std);
684 		SET_VALID_IOCTL(ops, VIDIOC_G_STD, vidioc_g_std);
685 		if (is_rx) {
686 			SET_VALID_IOCTL(ops, VIDIOC_QUERYSTD, vidioc_querystd);
687 			SET_VALID_IOCTL(ops, VIDIOC_ENUMINPUT, vidioc_enum_input);
688 			SET_VALID_IOCTL(ops, VIDIOC_G_INPUT, vidioc_g_input);
689 			SET_VALID_IOCTL(ops, VIDIOC_S_INPUT, vidioc_s_input);
690 			SET_VALID_IOCTL(ops, VIDIOC_ENUMAUDIO, vidioc_enumaudio);
691 			SET_VALID_IOCTL(ops, VIDIOC_G_AUDIO, vidioc_g_audio);
692 			SET_VALID_IOCTL(ops, VIDIOC_S_AUDIO, vidioc_s_audio);
693 			SET_VALID_IOCTL(ops, VIDIOC_QUERY_DV_TIMINGS, vidioc_query_dv_timings);
694 			SET_VALID_IOCTL(ops, VIDIOC_S_EDID, vidioc_s_edid);
695 		}
696 		if (is_tx) {
697 			SET_VALID_IOCTL(ops, VIDIOC_ENUMOUTPUT, vidioc_enum_output);
698 			SET_VALID_IOCTL(ops, VIDIOC_G_OUTPUT, vidioc_g_output);
699 			SET_VALID_IOCTL(ops, VIDIOC_S_OUTPUT, vidioc_s_output);
700 			SET_VALID_IOCTL(ops, VIDIOC_ENUMAUDOUT, vidioc_enumaudout);
701 			SET_VALID_IOCTL(ops, VIDIOC_G_AUDOUT, vidioc_g_audout);
702 			SET_VALID_IOCTL(ops, VIDIOC_S_AUDOUT, vidioc_s_audout);
703 		}
704 		if (ops->vidioc_g_parm || (vdev->vfl_type == VFL_TYPE_GRABBER &&
705 					ops->vidioc_g_std))
706 			set_bit(_IOC_NR(VIDIOC_G_PARM), valid_ioctls);
707 		SET_VALID_IOCTL(ops, VIDIOC_S_PARM, vidioc_s_parm);
708 		SET_VALID_IOCTL(ops, VIDIOC_S_DV_TIMINGS, vidioc_s_dv_timings);
709 		SET_VALID_IOCTL(ops, VIDIOC_G_DV_TIMINGS, vidioc_g_dv_timings);
710 		SET_VALID_IOCTL(ops, VIDIOC_ENUM_DV_TIMINGS, vidioc_enum_dv_timings);
711 		SET_VALID_IOCTL(ops, VIDIOC_DV_TIMINGS_CAP, vidioc_dv_timings_cap);
712 		SET_VALID_IOCTL(ops, VIDIOC_G_EDID, vidioc_g_edid);
713 	}
714 	if (is_tx && (is_radio || is_sdr)) {
715 		/* radio transmitter only ioctls */
716 		SET_VALID_IOCTL(ops, VIDIOC_G_MODULATOR, vidioc_g_modulator);
717 		SET_VALID_IOCTL(ops, VIDIOC_S_MODULATOR, vidioc_s_modulator);
718 	}
719 	if (is_rx) {
720 		/* receiver only ioctls */
721 		SET_VALID_IOCTL(ops, VIDIOC_G_TUNER, vidioc_g_tuner);
722 		SET_VALID_IOCTL(ops, VIDIOC_S_TUNER, vidioc_s_tuner);
723 		SET_VALID_IOCTL(ops, VIDIOC_S_HW_FREQ_SEEK, vidioc_s_hw_freq_seek);
724 	}
725 
726 	bitmap_andnot(vdev->valid_ioctls, valid_ioctls, vdev->valid_ioctls,
727 			BASE_VIDIOC_PRIVATE);
728 }
729 
video_register_media_controller(struct video_device * vdev,int type)730 static int video_register_media_controller(struct video_device *vdev, int type)
731 {
732 #if defined(CONFIG_MEDIA_CONTROLLER)
733 	u32 intf_type;
734 	int ret;
735 
736 	if (!vdev->v4l2_dev->mdev)
737 		return 0;
738 
739 	vdev->entity.obj_type = MEDIA_ENTITY_TYPE_VIDEO_DEVICE;
740 	vdev->entity.function = MEDIA_ENT_F_UNKNOWN;
741 
742 	switch (type) {
743 	case VFL_TYPE_GRABBER:
744 		intf_type = MEDIA_INTF_T_V4L_VIDEO;
745 		vdev->entity.function = MEDIA_ENT_F_IO_V4L;
746 		break;
747 	case VFL_TYPE_VBI:
748 		intf_type = MEDIA_INTF_T_V4L_VBI;
749 		vdev->entity.function = MEDIA_ENT_F_IO_VBI;
750 		break;
751 	case VFL_TYPE_SDR:
752 		intf_type = MEDIA_INTF_T_V4L_SWRADIO;
753 		vdev->entity.function = MEDIA_ENT_F_IO_SWRADIO;
754 		break;
755 	case VFL_TYPE_TOUCH:
756 		intf_type = MEDIA_INTF_T_V4L_TOUCH;
757 		vdev->entity.function = MEDIA_ENT_F_IO_V4L;
758 		break;
759 	case VFL_TYPE_RADIO:
760 		intf_type = MEDIA_INTF_T_V4L_RADIO;
761 		/*
762 		 * Radio doesn't have an entity at the V4L2 side to represent
763 		 * radio input or output. Instead, the audio input/output goes
764 		 * via either physical wires or ALSA.
765 		 */
766 		break;
767 	case VFL_TYPE_SUBDEV:
768 		intf_type = MEDIA_INTF_T_V4L_SUBDEV;
769 		/* Entity will be created via v4l2_device_register_subdev() */
770 		break;
771 	default:
772 		return 0;
773 	}
774 
775 	if (vdev->entity.function != MEDIA_ENT_F_UNKNOWN) {
776 		vdev->entity.name = vdev->name;
777 
778 		/* Needed just for backward compatibility with legacy MC API */
779 		vdev->entity.info.dev.major = VIDEO_MAJOR;
780 		vdev->entity.info.dev.minor = vdev->minor;
781 
782 		ret = media_device_register_entity(vdev->v4l2_dev->mdev,
783 						   &vdev->entity);
784 		if (ret < 0) {
785 			printk(KERN_WARNING
786 				"%s: media_device_register_entity failed\n",
787 				__func__);
788 			return ret;
789 		}
790 	}
791 
792 	vdev->intf_devnode = media_devnode_create(vdev->v4l2_dev->mdev,
793 						  intf_type,
794 						  0, VIDEO_MAJOR,
795 						  vdev->minor);
796 	if (!vdev->intf_devnode) {
797 		media_device_unregister_entity(&vdev->entity);
798 		return -ENOMEM;
799 	}
800 
801 	if (vdev->entity.function != MEDIA_ENT_F_UNKNOWN) {
802 		struct media_link *link;
803 
804 		link = media_create_intf_link(&vdev->entity,
805 					      &vdev->intf_devnode->intf,
806 					      MEDIA_LNK_FL_ENABLED);
807 		if (!link) {
808 			media_devnode_remove(vdev->intf_devnode);
809 			media_device_unregister_entity(&vdev->entity);
810 			return -ENOMEM;
811 		}
812 	}
813 
814 	/* FIXME: how to create the other interface links? */
815 
816 #endif
817 	return 0;
818 }
819 
__video_register_device(struct video_device * vdev,int type,int nr,int warn_if_nr_in_use,struct module * owner)820 int __video_register_device(struct video_device *vdev, int type, int nr,
821 		int warn_if_nr_in_use, struct module *owner)
822 {
823 	int i = 0;
824 	int ret;
825 	int minor_offset = 0;
826 	int minor_cnt = VIDEO_NUM_DEVICES;
827 	const char *name_base;
828 
829 	/* A minor value of -1 marks this video device as never
830 	   having been registered */
831 	vdev->minor = -1;
832 
833 	/* the release callback MUST be present */
834 	if (WARN_ON(!vdev->release))
835 		return -EINVAL;
836 	/* the v4l2_dev pointer MUST be present */
837 	if (WARN_ON(!vdev->v4l2_dev))
838 		return -EINVAL;
839 
840 	/* v4l2_fh support */
841 	spin_lock_init(&vdev->fh_lock);
842 	INIT_LIST_HEAD(&vdev->fh_list);
843 
844 	/* Part 1: check device type */
845 	switch (type) {
846 	case VFL_TYPE_GRABBER:
847 		name_base = "video";
848 		break;
849 	case VFL_TYPE_VBI:
850 		name_base = "vbi";
851 		break;
852 	case VFL_TYPE_RADIO:
853 		name_base = "radio";
854 		break;
855 	case VFL_TYPE_SUBDEV:
856 		name_base = "v4l-subdev";
857 		break;
858 	case VFL_TYPE_SDR:
859 		/* Use device name 'swradio' because 'sdr' was already taken. */
860 		name_base = "swradio";
861 		break;
862 	case VFL_TYPE_TOUCH:
863 		name_base = "v4l-touch";
864 		break;
865 	default:
866 		printk(KERN_ERR "%s called with unknown type: %d\n",
867 		       __func__, type);
868 		return -EINVAL;
869 	}
870 
871 	vdev->vfl_type = type;
872 	vdev->cdev = NULL;
873 	if (vdev->dev_parent == NULL)
874 		vdev->dev_parent = vdev->v4l2_dev->dev;
875 	if (vdev->ctrl_handler == NULL)
876 		vdev->ctrl_handler = vdev->v4l2_dev->ctrl_handler;
877 	/* If the prio state pointer is NULL, then use the v4l2_device
878 	   prio state. */
879 	if (vdev->prio == NULL)
880 		vdev->prio = &vdev->v4l2_dev->prio;
881 
882 	/* Part 2: find a free minor, device node number and device index. */
883 #ifdef CONFIG_VIDEO_FIXED_MINOR_RANGES
884 	/* Keep the ranges for the first four types for historical
885 	 * reasons.
886 	 * Newer devices (not yet in place) should use the range
887 	 * of 128-191 and just pick the first free minor there
888 	 * (new style). */
889 	switch (type) {
890 	case VFL_TYPE_GRABBER:
891 		minor_offset = 0;
892 		minor_cnt = 64;
893 		break;
894 	case VFL_TYPE_RADIO:
895 		minor_offset = 64;
896 		minor_cnt = 64;
897 		break;
898 	case VFL_TYPE_VBI:
899 		minor_offset = 224;
900 		minor_cnt = 32;
901 		break;
902 	default:
903 		minor_offset = 128;
904 		minor_cnt = 64;
905 		break;
906 	}
907 #endif
908 
909 	/* Pick a device node number */
910 	mutex_lock(&videodev_lock);
911 	nr = devnode_find(vdev, nr == -1 ? 0 : nr, minor_cnt);
912 	if (nr == minor_cnt)
913 		nr = devnode_find(vdev, 0, minor_cnt);
914 	if (nr == minor_cnt) {
915 		printk(KERN_ERR "could not get a free device node number\n");
916 		mutex_unlock(&videodev_lock);
917 		return -ENFILE;
918 	}
919 #ifdef CONFIG_VIDEO_FIXED_MINOR_RANGES
920 	/* 1-on-1 mapping of device node number to minor number */
921 	i = nr;
922 #else
923 	/* The device node number and minor numbers are independent, so
924 	   we just find the first free minor number. */
925 	for (i = 0; i < VIDEO_NUM_DEVICES; i++)
926 		if (video_device[i] == NULL)
927 			break;
928 	if (i == VIDEO_NUM_DEVICES) {
929 		mutex_unlock(&videodev_lock);
930 		printk(KERN_ERR "could not get a free minor\n");
931 		return -ENFILE;
932 	}
933 #endif
934 	vdev->minor = i + minor_offset;
935 	vdev->num = nr;
936 	devnode_set(vdev);
937 
938 	/* Should not happen since we thought this minor was free */
939 	WARN_ON(video_device[vdev->minor] != NULL);
940 	vdev->index = get_index(vdev);
941 	video_device[vdev->minor] = vdev;
942 	mutex_unlock(&videodev_lock);
943 
944 	if (vdev->ioctl_ops)
945 		determine_valid_ioctls(vdev);
946 
947 	/* Part 3: Initialize the character device */
948 	vdev->cdev = cdev_alloc();
949 	if (vdev->cdev == NULL) {
950 		ret = -ENOMEM;
951 		goto cleanup;
952 	}
953 	vdev->cdev->ops = &v4l2_fops;
954 	vdev->cdev->owner = owner;
955 	ret = cdev_add(vdev->cdev, MKDEV(VIDEO_MAJOR, vdev->minor), 1);
956 	if (ret < 0) {
957 		printk(KERN_ERR "%s: cdev_add failed\n", __func__);
958 		kfree(vdev->cdev);
959 		vdev->cdev = NULL;
960 		goto cleanup;
961 	}
962 
963 	/* Part 4: register the device with sysfs */
964 	vdev->dev.class = &video_class;
965 	vdev->dev.devt = MKDEV(VIDEO_MAJOR, vdev->minor);
966 	vdev->dev.parent = vdev->dev_parent;
967 	dev_set_name(&vdev->dev, "%s%d", name_base, vdev->num);
968 	ret = device_register(&vdev->dev);
969 	if (ret < 0) {
970 		printk(KERN_ERR "%s: device_register failed\n", __func__);
971 		goto cleanup;
972 	}
973 	/* Register the release callback that will be called when the last
974 	   reference to the device goes away. */
975 	vdev->dev.release = v4l2_device_release;
976 
977 	if (nr != -1 && nr != vdev->num && warn_if_nr_in_use)
978 		printk(KERN_WARNING "%s: requested %s%d, got %s\n", __func__,
979 			name_base, nr, video_device_node_name(vdev));
980 
981 	/* Increase v4l2_device refcount */
982 	v4l2_device_get(vdev->v4l2_dev);
983 
984 	/* Part 5: Register the entity. */
985 	ret = video_register_media_controller(vdev, type);
986 
987 	/* Part 6: Activate this minor. The char device can now be used. */
988 	set_bit(V4L2_FL_REGISTERED, &vdev->flags);
989 
990 	return 0;
991 
992 cleanup:
993 	mutex_lock(&videodev_lock);
994 	if (vdev->cdev)
995 		cdev_del(vdev->cdev);
996 	video_device[vdev->minor] = NULL;
997 	devnode_clear(vdev);
998 	mutex_unlock(&videodev_lock);
999 	/* Mark this video device as never having been registered. */
1000 	vdev->minor = -1;
1001 	return ret;
1002 }
1003 EXPORT_SYMBOL(__video_register_device);
1004 
1005 /**
1006  *	video_unregister_device - unregister a video4linux device
1007  *	@vdev: the device to unregister
1008  *
1009  *	This unregisters the passed device. Future open calls will
1010  *	be met with errors.
1011  */
video_unregister_device(struct video_device * vdev)1012 void video_unregister_device(struct video_device *vdev)
1013 {
1014 	/* Check if vdev was ever registered at all */
1015 	if (!vdev || !video_is_registered(vdev))
1016 		return;
1017 
1018 	mutex_lock(&videodev_lock);
1019 	/* This must be in a critical section to prevent a race with v4l2_open.
1020 	 * Once this bit has been cleared video_get may never be called again.
1021 	 */
1022 	clear_bit(V4L2_FL_REGISTERED, &vdev->flags);
1023 	mutex_unlock(&videodev_lock);
1024 	device_unregister(&vdev->dev);
1025 }
1026 EXPORT_SYMBOL(video_unregister_device);
1027 
1028 /*
1029  *	Initialise video for linux
1030  */
videodev_init(void)1031 static int __init videodev_init(void)
1032 {
1033 	dev_t dev = MKDEV(VIDEO_MAJOR, 0);
1034 	int ret;
1035 
1036 	printk(KERN_INFO "Linux video capture interface: v2.00\n");
1037 	ret = register_chrdev_region(dev, VIDEO_NUM_DEVICES, VIDEO_NAME);
1038 	if (ret < 0) {
1039 		printk(KERN_WARNING "videodev: unable to get major %d\n",
1040 				VIDEO_MAJOR);
1041 		return ret;
1042 	}
1043 
1044 	ret = class_register(&video_class);
1045 	if (ret < 0) {
1046 		unregister_chrdev_region(dev, VIDEO_NUM_DEVICES);
1047 		printk(KERN_WARNING "video_dev: class_register failed\n");
1048 		return -EIO;
1049 	}
1050 
1051 	return 0;
1052 }
1053 
videodev_exit(void)1054 static void __exit videodev_exit(void)
1055 {
1056 	dev_t dev = MKDEV(VIDEO_MAJOR, 0);
1057 
1058 	class_unregister(&video_class);
1059 	unregister_chrdev_region(dev, VIDEO_NUM_DEVICES);
1060 }
1061 
1062 subsys_initcall(videodev_init);
1063 module_exit(videodev_exit)
1064 
1065 MODULE_AUTHOR("Alan Cox, Mauro Carvalho Chehab <mchehab@infradead.org>");
1066 MODULE_DESCRIPTION("Device registrar for Video4Linux drivers v2");
1067 MODULE_LICENSE("GPL");
1068 MODULE_ALIAS_CHARDEV_MAJOR(VIDEO_MAJOR);
1069