xref: /openbmc/linux/drivers/hid/usbhid/hiddev.c (revision b04b4f78)
1 /*
2  *  Copyright (c) 2001 Paul Stewart
3  *  Copyright (c) 2001 Vojtech Pavlik
4  *
5  *  HID char devices, giving access to raw HID device events.
6  *
7  */
8 
9 /*
10  * This program is free software; you can redistribute it and/or modify
11  * it under the terms of the GNU General Public License as published by
12  * the Free Software Foundation; either version 2 of the License, or
13  * (at your option) any later version.
14  *
15  * This program is distributed in the hope that it will be useful,
16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
18  * GNU General Public License for more details.
19  *
20  * You should have received a copy of the GNU General Public License
21  * along with this program; if not, write to the Free Software
22  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
23  *
24  * Should you need to contact me, the author, you can do so either by
25  * e-mail - mail your message to Paul Stewart <stewart@wetlogic.net>
26  */
27 
28 #include <linux/poll.h>
29 #include <linux/slab.h>
30 #include <linux/module.h>
31 #include <linux/init.h>
32 #include <linux/smp_lock.h>
33 #include <linux/input.h>
34 #include <linux/usb.h>
35 #include <linux/hid.h>
36 #include <linux/hiddev.h>
37 #include <linux/compat.h>
38 #include "usbhid.h"
39 
40 #ifdef CONFIG_USB_DYNAMIC_MINORS
41 #define HIDDEV_MINOR_BASE	0
42 #define HIDDEV_MINORS		256
43 #else
44 #define HIDDEV_MINOR_BASE	96
45 #define HIDDEV_MINORS		16
46 #endif
47 #define HIDDEV_BUFFER_SIZE	64
48 
49 struct hiddev {
50 	int exist;
51 	int open;
52 	struct mutex existancelock;
53 	wait_queue_head_t wait;
54 	struct hid_device *hid;
55 	struct list_head list;
56 	spinlock_t list_lock;
57 };
58 
59 struct hiddev_list {
60 	struct hiddev_usage_ref buffer[HIDDEV_BUFFER_SIZE];
61 	int head;
62 	int tail;
63 	unsigned flags;
64 	struct fasync_struct *fasync;
65 	struct hiddev *hiddev;
66 	struct list_head node;
67 	struct mutex thread_lock;
68 };
69 
70 static struct hiddev *hiddev_table[HIDDEV_MINORS];
71 
72 /*
73  * Find a report, given the report's type and ID.  The ID can be specified
74  * indirectly by REPORT_ID_FIRST (which returns the first report of the given
75  * type) or by (REPORT_ID_NEXT | old_id), which returns the next report of the
76  * given type which follows old_id.
77  */
78 static struct hid_report *
79 hiddev_lookup_report(struct hid_device *hid, struct hiddev_report_info *rinfo)
80 {
81 	unsigned int flags = rinfo->report_id & ~HID_REPORT_ID_MASK;
82 	unsigned int rid = rinfo->report_id & HID_REPORT_ID_MASK;
83 	struct hid_report_enum *report_enum;
84 	struct hid_report *report;
85 	struct list_head *list;
86 
87 	if (rinfo->report_type < HID_REPORT_TYPE_MIN ||
88 	    rinfo->report_type > HID_REPORT_TYPE_MAX)
89 		return NULL;
90 
91 	report_enum = hid->report_enum +
92 		(rinfo->report_type - HID_REPORT_TYPE_MIN);
93 
94 	switch (flags) {
95 	case 0: /* Nothing to do -- report_id is already set correctly */
96 		break;
97 
98 	case HID_REPORT_ID_FIRST:
99 		if (list_empty(&report_enum->report_list))
100 			return NULL;
101 
102 		list = report_enum->report_list.next;
103 		report = list_entry(list, struct hid_report, list);
104 		rinfo->report_id = report->id;
105 		break;
106 
107 	case HID_REPORT_ID_NEXT:
108 		report = report_enum->report_id_hash[rid];
109 		if (!report)
110 			return NULL;
111 
112 		list = report->list.next;
113 		if (list == &report_enum->report_list)
114 			return NULL;
115 
116 		report = list_entry(list, struct hid_report, list);
117 		rinfo->report_id = report->id;
118 		break;
119 
120 	default:
121 		return NULL;
122 	}
123 
124 	return report_enum->report_id_hash[rinfo->report_id];
125 }
126 
127 /*
128  * Perform an exhaustive search of the report table for a usage, given its
129  * type and usage id.
130  */
131 static struct hid_field *
132 hiddev_lookup_usage(struct hid_device *hid, struct hiddev_usage_ref *uref)
133 {
134 	int i, j;
135 	struct hid_report *report;
136 	struct hid_report_enum *report_enum;
137 	struct hid_field *field;
138 
139 	if (uref->report_type < HID_REPORT_TYPE_MIN ||
140 	    uref->report_type > HID_REPORT_TYPE_MAX)
141 		return NULL;
142 
143 	report_enum = hid->report_enum +
144 		(uref->report_type - HID_REPORT_TYPE_MIN);
145 
146 	list_for_each_entry(report, &report_enum->report_list, list) {
147 		for (i = 0; i < report->maxfield; i++) {
148 			field = report->field[i];
149 			for (j = 0; j < field->maxusage; j++) {
150 				if (field->usage[j].hid == uref->usage_code) {
151 					uref->report_id = report->id;
152 					uref->field_index = i;
153 					uref->usage_index = j;
154 					return field;
155 				}
156 			}
157 		}
158 	}
159 
160 	return NULL;
161 }
162 
163 static void hiddev_send_event(struct hid_device *hid,
164 			      struct hiddev_usage_ref *uref)
165 {
166 	struct hiddev *hiddev = hid->hiddev;
167 	struct hiddev_list *list;
168 	unsigned long flags;
169 
170 	spin_lock_irqsave(&hiddev->list_lock, flags);
171 	list_for_each_entry(list, &hiddev->list, node) {
172 		if (uref->field_index != HID_FIELD_INDEX_NONE ||
173 		    (list->flags & HIDDEV_FLAG_REPORT) != 0) {
174 			list->buffer[list->head] = *uref;
175 			list->head = (list->head + 1) &
176 				(HIDDEV_BUFFER_SIZE - 1);
177 			kill_fasync(&list->fasync, SIGIO, POLL_IN);
178 		}
179 	}
180 	spin_unlock_irqrestore(&hiddev->list_lock, flags);
181 
182 	wake_up_interruptible(&hiddev->wait);
183 }
184 
185 /*
186  * This is where hid.c calls into hiddev to pass an event that occurred over
187  * the interrupt pipe
188  */
189 void hiddev_hid_event(struct hid_device *hid, struct hid_field *field,
190 		      struct hid_usage *usage, __s32 value)
191 {
192 	unsigned type = field->report_type;
193 	struct hiddev_usage_ref uref;
194 
195 	uref.report_type =
196 	  (type == HID_INPUT_REPORT) ? HID_REPORT_TYPE_INPUT :
197 	  ((type == HID_OUTPUT_REPORT) ? HID_REPORT_TYPE_OUTPUT :
198 	   ((type == HID_FEATURE_REPORT) ? HID_REPORT_TYPE_FEATURE : 0));
199 	uref.report_id = field->report->id;
200 	uref.field_index = field->index;
201 	uref.usage_index = (usage - field->usage);
202 	uref.usage_code = usage->hid;
203 	uref.value = value;
204 
205 	hiddev_send_event(hid, &uref);
206 }
207 EXPORT_SYMBOL_GPL(hiddev_hid_event);
208 
209 void hiddev_report_event(struct hid_device *hid, struct hid_report *report)
210 {
211 	unsigned type = report->type;
212 	struct hiddev_usage_ref uref;
213 
214 	memset(&uref, 0, sizeof(uref));
215 	uref.report_type =
216 	  (type == HID_INPUT_REPORT) ? HID_REPORT_TYPE_INPUT :
217 	  ((type == HID_OUTPUT_REPORT) ? HID_REPORT_TYPE_OUTPUT :
218 	   ((type == HID_FEATURE_REPORT) ? HID_REPORT_TYPE_FEATURE : 0));
219 	uref.report_id = report->id;
220 	uref.field_index = HID_FIELD_INDEX_NONE;
221 
222 	hiddev_send_event(hid, &uref);
223 }
224 
225 /*
226  * fasync file op
227  */
228 static int hiddev_fasync(int fd, struct file *file, int on)
229 {
230 	struct hiddev_list *list = file->private_data;
231 
232 	return fasync_helper(fd, file, on, &list->fasync);
233 }
234 
235 
236 /*
237  * release file op
238  */
239 static int hiddev_release(struct inode * inode, struct file * file)
240 {
241 	struct hiddev_list *list = file->private_data;
242 	unsigned long flags;
243 
244 	spin_lock_irqsave(&list->hiddev->list_lock, flags);
245 	list_del(&list->node);
246 	spin_unlock_irqrestore(&list->hiddev->list_lock, flags);
247 
248 	if (!--list->hiddev->open) {
249 		if (list->hiddev->exist) {
250 			usbhid_close(list->hiddev->hid);
251 			usbhid_put_power(list->hiddev->hid);
252 		} else {
253 			kfree(list->hiddev);
254 		}
255 	}
256 
257 	kfree(list);
258 
259 	return 0;
260 }
261 
262 /*
263  * open file op
264  */
265 static int hiddev_open(struct inode *inode, struct file *file)
266 {
267 	struct hiddev_list *list;
268 	int res;
269 
270 	int i = iminor(inode) - HIDDEV_MINOR_BASE;
271 
272 	if (i >= HIDDEV_MINORS || i < 0 || !hiddev_table[i])
273 		return -ENODEV;
274 
275 	if (!(list = kzalloc(sizeof(struct hiddev_list), GFP_KERNEL)))
276 		return -ENOMEM;
277 	mutex_init(&list->thread_lock);
278 
279 	list->hiddev = hiddev_table[i];
280 
281 
282 	file->private_data = list;
283 
284 	/*
285 	 * no need for locking because the USB major number
286 	 * is shared which usbcore guards against disconnect
287 	 */
288 	if (list->hiddev->exist) {
289 		if (!list->hiddev->open++) {
290 			res = usbhid_open(hiddev_table[i]->hid);
291 			if (res < 0) {
292 				res = -EIO;
293 				goto bail;
294 			}
295 		}
296 	} else {
297 		res = -ENODEV;
298 		goto bail;
299 	}
300 
301 	spin_lock_irq(&list->hiddev->list_lock);
302 	list_add_tail(&list->node, &hiddev_table[i]->list);
303 	spin_unlock_irq(&list->hiddev->list_lock);
304 
305 	if (!list->hiddev->open++)
306 		if (list->hiddev->exist) {
307 			struct hid_device *hid = hiddev_table[i]->hid;
308 			res = usbhid_get_power(hid);
309 			if (res < 0) {
310 				res = -EIO;
311 				goto bail;
312 			}
313 			usbhid_open(hid);
314 		}
315 
316 	return 0;
317 bail:
318 	file->private_data = NULL;
319 	kfree(list);
320 	return res;
321 }
322 
323 /*
324  * "write" file op
325  */
326 static ssize_t hiddev_write(struct file * file, const char __user * buffer, size_t count, loff_t *ppos)
327 {
328 	return -EINVAL;
329 }
330 
331 /*
332  * "read" file op
333  */
334 static ssize_t hiddev_read(struct file * file, char __user * buffer, size_t count, loff_t *ppos)
335 {
336 	DEFINE_WAIT(wait);
337 	struct hiddev_list *list = file->private_data;
338 	int event_size;
339 	int retval;
340 
341 	event_size = ((list->flags & HIDDEV_FLAG_UREF) != 0) ?
342 		sizeof(struct hiddev_usage_ref) : sizeof(struct hiddev_event);
343 
344 	if (count < event_size)
345 		return 0;
346 
347 	/* lock against other threads */
348 	retval = mutex_lock_interruptible(&list->thread_lock);
349 	if (retval)
350 		return -ERESTARTSYS;
351 
352 	while (retval == 0) {
353 		if (list->head == list->tail) {
354 			prepare_to_wait(&list->hiddev->wait, &wait, TASK_INTERRUPTIBLE);
355 
356 			while (list->head == list->tail) {
357 				if (file->f_flags & O_NONBLOCK) {
358 					retval = -EAGAIN;
359 					break;
360 				}
361 				if (signal_pending(current)) {
362 					retval = -ERESTARTSYS;
363 					break;
364 				}
365 				if (!list->hiddev->exist) {
366 					retval = -EIO;
367 					break;
368 				}
369 
370 				/* let O_NONBLOCK tasks run */
371 				mutex_unlock(&list->thread_lock);
372 				schedule();
373 				if (mutex_lock_interruptible(&list->thread_lock))
374 					return -EINTR;
375 				set_current_state(TASK_INTERRUPTIBLE);
376 			}
377 			finish_wait(&list->hiddev->wait, &wait);
378 
379 		}
380 
381 		if (retval) {
382 			mutex_unlock(&list->thread_lock);
383 			return retval;
384 		}
385 
386 
387 		while (list->head != list->tail &&
388 		       retval + event_size <= count) {
389 			if ((list->flags & HIDDEV_FLAG_UREF) == 0) {
390 				if (list->buffer[list->tail].field_index != HID_FIELD_INDEX_NONE) {
391 					struct hiddev_event event;
392 
393 					event.hid = list->buffer[list->tail].usage_code;
394 					event.value = list->buffer[list->tail].value;
395 					if (copy_to_user(buffer + retval, &event, sizeof(struct hiddev_event))) {
396 						mutex_unlock(&list->thread_lock);
397 						return -EFAULT;
398 					}
399 					retval += sizeof(struct hiddev_event);
400 				}
401 			} else {
402 				if (list->buffer[list->tail].field_index != HID_FIELD_INDEX_NONE ||
403 				    (list->flags & HIDDEV_FLAG_REPORT) != 0) {
404 
405 					if (copy_to_user(buffer + retval, list->buffer + list->tail, sizeof(struct hiddev_usage_ref))) {
406 						mutex_unlock(&list->thread_lock);
407 						return -EFAULT;
408 					}
409 					retval += sizeof(struct hiddev_usage_ref);
410 				}
411 			}
412 			list->tail = (list->tail + 1) & (HIDDEV_BUFFER_SIZE - 1);
413 		}
414 
415 	}
416 	mutex_unlock(&list->thread_lock);
417 
418 	return retval;
419 }
420 
421 /*
422  * "poll" file op
423  * No kernel lock - fine
424  */
425 static unsigned int hiddev_poll(struct file *file, poll_table *wait)
426 {
427 	struct hiddev_list *list = file->private_data;
428 
429 	poll_wait(file, &list->hiddev->wait, wait);
430 	if (list->head != list->tail)
431 		return POLLIN | POLLRDNORM;
432 	if (!list->hiddev->exist)
433 		return POLLERR | POLLHUP;
434 	return 0;
435 }
436 
437 /*
438  * "ioctl" file op
439  */
440 static noinline int hiddev_ioctl_usage(struct hiddev *hiddev, unsigned int cmd, void __user *user_arg)
441 {
442 	struct hid_device *hid = hiddev->hid;
443 	struct hiddev_report_info rinfo;
444 	struct hiddev_usage_ref_multi *uref_multi = NULL;
445 	struct hiddev_usage_ref *uref;
446 	struct hid_report *report;
447 	struct hid_field *field;
448 	int i;
449 
450 	uref_multi = kmalloc(sizeof(struct hiddev_usage_ref_multi), GFP_KERNEL);
451 	if (!uref_multi)
452 		return -ENOMEM;
453 	lock_kernel();
454 	uref = &uref_multi->uref;
455 	if (cmd == HIDIOCGUSAGES || cmd == HIDIOCSUSAGES) {
456 		if (copy_from_user(uref_multi, user_arg,
457 				   sizeof(*uref_multi)))
458 			goto fault;
459 	} else {
460 		if (copy_from_user(uref, user_arg, sizeof(*uref)))
461 			goto fault;
462 	}
463 
464 	switch (cmd) {
465 	case HIDIOCGUCODE:
466 		rinfo.report_type = uref->report_type;
467 		rinfo.report_id = uref->report_id;
468 		if ((report = hiddev_lookup_report(hid, &rinfo)) == NULL)
469 			goto inval;
470 
471 		if (uref->field_index >= report->maxfield)
472 			goto inval;
473 
474 		field = report->field[uref->field_index];
475 		if (uref->usage_index >= field->maxusage)
476 			goto inval;
477 
478 		uref->usage_code = field->usage[uref->usage_index].hid;
479 
480 		if (copy_to_user(user_arg, uref, sizeof(*uref)))
481 			goto fault;
482 
483 		goto goodreturn;
484 
485 	default:
486 		if (cmd != HIDIOCGUSAGE &&
487 		    cmd != HIDIOCGUSAGES &&
488 		    uref->report_type == HID_REPORT_TYPE_INPUT)
489 			goto inval;
490 
491 		if (uref->report_id == HID_REPORT_ID_UNKNOWN) {
492 			field = hiddev_lookup_usage(hid, uref);
493 			if (field == NULL)
494 				goto inval;
495 		} else {
496 			rinfo.report_type = uref->report_type;
497 			rinfo.report_id = uref->report_id;
498 			if ((report = hiddev_lookup_report(hid, &rinfo)) == NULL)
499 				goto inval;
500 
501 			if (uref->field_index >= report->maxfield)
502 				goto inval;
503 
504 			field = report->field[uref->field_index];
505 
506 			if (cmd == HIDIOCGCOLLECTIONINDEX) {
507 				if (uref->usage_index >= field->maxusage)
508 					goto inval;
509 			} else if (uref->usage_index >= field->report_count)
510 				goto inval;
511 
512 			else if ((cmd == HIDIOCGUSAGES || cmd == HIDIOCSUSAGES) &&
513 				 (uref_multi->num_values > HID_MAX_MULTI_USAGES ||
514 				  uref->usage_index + uref_multi->num_values > field->report_count))
515 				goto inval;
516 			}
517 
518 		switch (cmd) {
519 		case HIDIOCGUSAGE:
520 			uref->value = field->value[uref->usage_index];
521 			if (copy_to_user(user_arg, uref, sizeof(*uref)))
522 				goto fault;
523 			goto goodreturn;
524 
525 		case HIDIOCSUSAGE:
526 			field->value[uref->usage_index] = uref->value;
527 			goto goodreturn;
528 
529 		case HIDIOCGCOLLECTIONINDEX:
530 			kfree(uref_multi);
531 			return field->usage[uref->usage_index].collection_index;
532 		case HIDIOCGUSAGES:
533 			for (i = 0; i < uref_multi->num_values; i++)
534 				uref_multi->values[i] =
535 				    field->value[uref->usage_index + i];
536 			if (copy_to_user(user_arg, uref_multi,
537 					 sizeof(*uref_multi)))
538 				goto fault;
539 			goto goodreturn;
540 		case HIDIOCSUSAGES:
541 			for (i = 0; i < uref_multi->num_values; i++)
542 				field->value[uref->usage_index + i] =
543 				    uref_multi->values[i];
544 			goto goodreturn;
545 		}
546 
547 goodreturn:
548 		unlock_kernel();
549 		kfree(uref_multi);
550 		return 0;
551 fault:
552 		unlock_kernel();
553 		kfree(uref_multi);
554 		return -EFAULT;
555 inval:
556 		unlock_kernel();
557 		kfree(uref_multi);
558 		return -EINVAL;
559 	}
560 }
561 
562 static noinline int hiddev_ioctl_string(struct hiddev *hiddev, unsigned int cmd, void __user *user_arg)
563 {
564 	struct hid_device *hid = hiddev->hid;
565 	struct usb_device *dev = hid_to_usb_dev(hid);
566 	int idx, len;
567 	char *buf;
568 
569 	if (get_user(idx, (int __user *)user_arg))
570 		return -EFAULT;
571 
572 	if ((buf = kmalloc(HID_STRING_SIZE, GFP_KERNEL)) == NULL)
573 		return -ENOMEM;
574 
575 	if ((len = usb_string(dev, idx, buf, HID_STRING_SIZE-1)) < 0) {
576 		kfree(buf);
577 		return -EINVAL;
578 	}
579 
580 	if (copy_to_user(user_arg+sizeof(int), buf, len+1)) {
581 		kfree(buf);
582 		return -EFAULT;
583 	}
584 
585 	kfree(buf);
586 
587 	return len;
588 }
589 
590 static long hiddev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
591 {
592 	struct hiddev_list *list = file->private_data;
593 	struct hiddev *hiddev = list->hiddev;
594 	struct hid_device *hid = hiddev->hid;
595 	struct usb_device *dev = hid_to_usb_dev(hid);
596 	struct hiddev_collection_info cinfo;
597 	struct hiddev_report_info rinfo;
598 	struct hiddev_field_info finfo;
599 	struct hiddev_devinfo dinfo;
600 	struct hid_report *report;
601 	struct hid_field *field;
602 	struct usbhid_device *usbhid = hid->driver_data;
603 	void __user *user_arg = (void __user *)arg;
604 	int i, r;
605 
606 	/* Called without BKL by compat methods so no BKL taken */
607 
608 	/* FIXME: Who or what stop this racing with a disconnect ?? */
609 	if (!hiddev->exist)
610 		return -EIO;
611 
612 	switch (cmd) {
613 
614 	case HIDIOCGVERSION:
615 		return put_user(HID_VERSION, (int __user *)arg);
616 
617 	case HIDIOCAPPLICATION:
618 		if (arg < 0 || arg >= hid->maxapplication)
619 			return -EINVAL;
620 
621 		for (i = 0; i < hid->maxcollection; i++)
622 			if (hid->collection[i].type ==
623 			    HID_COLLECTION_APPLICATION && arg-- == 0)
624 				break;
625 
626 		if (i == hid->maxcollection)
627 			return -EINVAL;
628 
629 		return hid->collection[i].usage;
630 
631 	case HIDIOCGDEVINFO:
632 		dinfo.bustype = BUS_USB;
633 		dinfo.busnum = dev->bus->busnum;
634 		dinfo.devnum = dev->devnum;
635 		dinfo.ifnum = usbhid->ifnum;
636 		dinfo.vendor = le16_to_cpu(dev->descriptor.idVendor);
637 		dinfo.product = le16_to_cpu(dev->descriptor.idProduct);
638 		dinfo.version = le16_to_cpu(dev->descriptor.bcdDevice);
639 		dinfo.num_applications = hid->maxapplication;
640 		if (copy_to_user(user_arg, &dinfo, sizeof(dinfo)))
641 			return -EFAULT;
642 
643 		return 0;
644 
645 	case HIDIOCGFLAG:
646 		if (put_user(list->flags, (int __user *)arg))
647 			return -EFAULT;
648 
649 		return 0;
650 
651 	case HIDIOCSFLAG:
652 		{
653 			int newflags;
654 			if (get_user(newflags, (int __user *)arg))
655 				return -EFAULT;
656 
657 			if ((newflags & ~HIDDEV_FLAGS) != 0 ||
658 			    ((newflags & HIDDEV_FLAG_REPORT) != 0 &&
659 			     (newflags & HIDDEV_FLAG_UREF) == 0))
660 				return -EINVAL;
661 
662 			list->flags = newflags;
663 
664 			return 0;
665 		}
666 
667 	case HIDIOCGSTRING:
668 		mutex_lock(&hiddev->existancelock);
669 		if (hiddev->exist)
670 			r = hiddev_ioctl_string(hiddev, cmd, user_arg);
671 		else
672 			r = -ENODEV;
673 		mutex_unlock(&hiddev->existancelock);
674 		return r;
675 
676 	case HIDIOCINITREPORT:
677 		mutex_lock(&hiddev->existancelock);
678 		if (!hiddev->exist) {
679 			mutex_unlock(&hiddev->existancelock);
680 			return -ENODEV;
681 		}
682 		usbhid_init_reports(hid);
683 		mutex_unlock(&hiddev->existancelock);
684 
685 		return 0;
686 
687 	case HIDIOCGREPORT:
688 		if (copy_from_user(&rinfo, user_arg, sizeof(rinfo)))
689 			return -EFAULT;
690 
691 		if (rinfo.report_type == HID_REPORT_TYPE_OUTPUT)
692 			return -EINVAL;
693 
694 		if ((report = hiddev_lookup_report(hid, &rinfo)) == NULL)
695 			return -EINVAL;
696 
697 		mutex_lock(&hiddev->existancelock);
698 		if (hiddev->exist) {
699 			usbhid_submit_report(hid, report, USB_DIR_IN);
700 			usbhid_wait_io(hid);
701 		}
702 		mutex_unlock(&hiddev->existancelock);
703 
704 		return 0;
705 
706 	case HIDIOCSREPORT:
707 		if (copy_from_user(&rinfo, user_arg, sizeof(rinfo)))
708 			return -EFAULT;
709 
710 		if (rinfo.report_type == HID_REPORT_TYPE_INPUT)
711 			return -EINVAL;
712 
713 		if ((report = hiddev_lookup_report(hid, &rinfo)) == NULL)
714 			return -EINVAL;
715 
716 		mutex_lock(&hiddev->existancelock);
717 		if (hiddev->exist) {
718 			usbhid_submit_report(hid, report, USB_DIR_OUT);
719 			usbhid_wait_io(hid);
720 		}
721 		mutex_unlock(&hiddev->existancelock);
722 
723 		return 0;
724 
725 	case HIDIOCGREPORTINFO:
726 		if (copy_from_user(&rinfo, user_arg, sizeof(rinfo)))
727 			return -EFAULT;
728 
729 		if ((report = hiddev_lookup_report(hid, &rinfo)) == NULL)
730 			return -EINVAL;
731 
732 		rinfo.num_fields = report->maxfield;
733 
734 		if (copy_to_user(user_arg, &rinfo, sizeof(rinfo)))
735 			return -EFAULT;
736 
737 		return 0;
738 
739 	case HIDIOCGFIELDINFO:
740 		if (copy_from_user(&finfo, user_arg, sizeof(finfo)))
741 			return -EFAULT;
742 		rinfo.report_type = finfo.report_type;
743 		rinfo.report_id = finfo.report_id;
744 		if ((report = hiddev_lookup_report(hid, &rinfo)) == NULL)
745 			return -EINVAL;
746 
747 		if (finfo.field_index >= report->maxfield)
748 			return -EINVAL;
749 
750 		field = report->field[finfo.field_index];
751 		memset(&finfo, 0, sizeof(finfo));
752 		finfo.report_type = rinfo.report_type;
753 		finfo.report_id = rinfo.report_id;
754 		finfo.field_index = field->report_count - 1;
755 		finfo.maxusage = field->maxusage;
756 		finfo.flags = field->flags;
757 		finfo.physical = field->physical;
758 		finfo.logical = field->logical;
759 		finfo.application = field->application;
760 		finfo.logical_minimum = field->logical_minimum;
761 		finfo.logical_maximum = field->logical_maximum;
762 		finfo.physical_minimum = field->physical_minimum;
763 		finfo.physical_maximum = field->physical_maximum;
764 		finfo.unit_exponent = field->unit_exponent;
765 		finfo.unit = field->unit;
766 
767 		if (copy_to_user(user_arg, &finfo, sizeof(finfo)))
768 			return -EFAULT;
769 
770 		return 0;
771 
772 	case HIDIOCGUCODE:
773 		/* fall through */
774 	case HIDIOCGUSAGE:
775 	case HIDIOCSUSAGE:
776 	case HIDIOCGUSAGES:
777 	case HIDIOCSUSAGES:
778 	case HIDIOCGCOLLECTIONINDEX:
779 		mutex_lock(&hiddev->existancelock);
780 		if (hiddev->exist)
781 			r = hiddev_ioctl_usage(hiddev, cmd, user_arg);
782 		else
783 			r = -ENODEV;
784 		mutex_unlock(&hiddev->existancelock);
785 		return r;
786 
787 	case HIDIOCGCOLLECTIONINFO:
788 		if (copy_from_user(&cinfo, user_arg, sizeof(cinfo)))
789 			return -EFAULT;
790 
791 		if (cinfo.index >= hid->maxcollection)
792 			return -EINVAL;
793 
794 		cinfo.type = hid->collection[cinfo.index].type;
795 		cinfo.usage = hid->collection[cinfo.index].usage;
796 		cinfo.level = hid->collection[cinfo.index].level;
797 
798 		if (copy_to_user(user_arg, &cinfo, sizeof(cinfo)))
799 			return -EFAULT;
800 		return 0;
801 
802 	default:
803 
804 		if (_IOC_TYPE(cmd) != 'H' || _IOC_DIR(cmd) != _IOC_READ)
805 			return -EINVAL;
806 
807 		if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGNAME(0))) {
808 			int len;
809 			if (!hid->name)
810 				return 0;
811 			len = strlen(hid->name) + 1;
812 			if (len > _IOC_SIZE(cmd))
813 				 len = _IOC_SIZE(cmd);
814 			return copy_to_user(user_arg, hid->name, len) ?
815 				-EFAULT : len;
816 		}
817 
818 		if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGPHYS(0))) {
819 			int len;
820 			if (!hid->phys)
821 				return 0;
822 			len = strlen(hid->phys) + 1;
823 			if (len > _IOC_SIZE(cmd))
824 				len = _IOC_SIZE(cmd);
825 			return copy_to_user(user_arg, hid->phys, len) ?
826 				-EFAULT : len;
827 		}
828 	}
829 	return -EINVAL;
830 }
831 
832 #ifdef CONFIG_COMPAT
833 static long hiddev_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
834 {
835 	return hiddev_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
836 }
837 #endif
838 
839 static const struct file_operations hiddev_fops = {
840 	.owner =	THIS_MODULE,
841 	.read =		hiddev_read,
842 	.write =	hiddev_write,
843 	.poll =		hiddev_poll,
844 	.open =		hiddev_open,
845 	.release =	hiddev_release,
846 	.unlocked_ioctl =	hiddev_ioctl,
847 	.fasync =	hiddev_fasync,
848 #ifdef CONFIG_COMPAT
849 	.compat_ioctl	= hiddev_compat_ioctl,
850 #endif
851 };
852 
853 static struct usb_class_driver hiddev_class = {
854 	.name =		"hiddev%d",
855 	.fops =		&hiddev_fops,
856 	.minor_base =	HIDDEV_MINOR_BASE,
857 };
858 
859 /*
860  * This is where hid.c calls us to connect a hid device to the hiddev driver
861  */
862 int hiddev_connect(struct hid_device *hid, unsigned int force)
863 {
864 	struct hiddev *hiddev;
865 	struct usbhid_device *usbhid = hid->driver_data;
866 	int retval;
867 
868 	if (!force) {
869 		unsigned int i;
870 		for (i = 0; i < hid->maxcollection; i++)
871 			if (hid->collection[i].type ==
872 			    HID_COLLECTION_APPLICATION &&
873 			    !IS_INPUT_APPLICATION(hid->collection[i].usage))
874 				break;
875 
876 		if (i == hid->maxcollection)
877 			return -1;
878 	}
879 
880 	if (!(hiddev = kzalloc(sizeof(struct hiddev), GFP_KERNEL)))
881 		return -1;
882 
883 	init_waitqueue_head(&hiddev->wait);
884 	INIT_LIST_HEAD(&hiddev->list);
885 	spin_lock_init(&hiddev->list_lock);
886 	mutex_init(&hiddev->existancelock);
887 	hid->hiddev = hiddev;
888 	hiddev->hid = hid;
889 	hiddev->exist = 1;
890 
891 	/* when lock_kernel() usage is fixed in usb_open(),
892 	 * we could also fix it here */
893 	lock_kernel();
894 	retval = usb_register_dev(usbhid->intf, &hiddev_class);
895 	if (retval) {
896 		err_hid("Not able to get a minor for this device.");
897 		hid->hiddev = NULL;
898 		unlock_kernel();
899 		kfree(hiddev);
900 		return -1;
901 	} else {
902 		hid->minor = usbhid->intf->minor;
903 		hiddev_table[usbhid->intf->minor - HIDDEV_MINOR_BASE] = hiddev;
904 	}
905 	unlock_kernel();
906 
907 	return 0;
908 }
909 
910 /*
911  * This is where hid.c calls us to disconnect a hiddev device from the
912  * corresponding hid device (usually because the usb device has disconnected)
913  */
914 static struct usb_class_driver hiddev_class;
915 void hiddev_disconnect(struct hid_device *hid)
916 {
917 	struct hiddev *hiddev = hid->hiddev;
918 	struct usbhid_device *usbhid = hid->driver_data;
919 
920 	mutex_lock(&hiddev->existancelock);
921 	hiddev->exist = 0;
922 	mutex_unlock(&hiddev->existancelock);
923 
924 	hiddev_table[hiddev->hid->minor - HIDDEV_MINOR_BASE] = NULL;
925 	usb_deregister_dev(usbhid->intf, &hiddev_class);
926 
927 	if (hiddev->open) {
928 		usbhid_close(hiddev->hid);
929 		wake_up_interruptible(&hiddev->wait);
930 	} else {
931 		kfree(hiddev);
932 	}
933 }
934 
935 /* Currently this driver is a USB driver.  It's not a conventional one in
936  * the sense that it doesn't probe at the USB level.  Instead it waits to
937  * be connected by HID through the hiddev_connect / hiddev_disconnect
938  * routines.  The reason to register as a USB device is to gain part of the
939  * minor number space from the USB major.
940  *
941  * In theory, should the HID code be generalized to more than one physical
942  * medium (say, IEEE 1384), this driver will probably need to register its
943  * own major number, and in doing so, no longer need to register with USB.
944  * At that point the probe routine and hiddev_driver struct below will no
945  * longer be useful.
946  */
947 
948 
949 /* We never attach in this manner, and rely on HID to connect us.  This
950  * is why there is no disconnect routine defined in the usb_driver either.
951  */
952 static int hiddev_usbd_probe(struct usb_interface *intf,
953 			     const struct usb_device_id *hiddev_info)
954 {
955 	return -ENODEV;
956 }
957 
958 
959 static /* const */ struct usb_driver hiddev_driver = {
960 	.name =		"hiddev",
961 	.probe =	hiddev_usbd_probe,
962 };
963 
964 int __init hiddev_init(void)
965 {
966 	return usb_register(&hiddev_driver);
967 }
968 
969 void hiddev_exit(void)
970 {
971 	usb_deregister(&hiddev_driver);
972 }
973