xref: /openbmc/linux/drivers/hid/usbhid/hiddev.c (revision df2634f43f5106947f3735a0b61a6527a4b278cd)
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/input.h>
33 #include <linux/usb.h>
34 #include <linux/hid.h>
35 #include <linux/hiddev.h>
36 #include <linux/compat.h>
37 #include "usbhid.h"
38 
39 #ifdef CONFIG_USB_DYNAMIC_MINORS
40 #define HIDDEV_MINOR_BASE	0
41 #define HIDDEV_MINORS		256
42 #else
43 #define HIDDEV_MINOR_BASE	96
44 #define HIDDEV_MINORS		16
45 #endif
46 #define HIDDEV_BUFFER_SIZE	2048
47 
48 struct hiddev {
49 	int exist;
50 	int open;
51 	struct mutex existancelock;
52 	wait_queue_head_t wait;
53 	struct hid_device *hid;
54 	struct list_head list;
55 	spinlock_t list_lock;
56 };
57 
58 struct hiddev_list {
59 	struct hiddev_usage_ref buffer[HIDDEV_BUFFER_SIZE];
60 	int head;
61 	int tail;
62 	unsigned flags;
63 	struct fasync_struct *fasync;
64 	struct hiddev *hiddev;
65 	struct list_head node;
66 	struct mutex thread_lock;
67 };
68 
69 /*
70  * Find a report, given the report's type and ID.  The ID can be specified
71  * indirectly by REPORT_ID_FIRST (which returns the first report of the given
72  * type) or by (REPORT_ID_NEXT | old_id), which returns the next report of the
73  * given type which follows old_id.
74  */
75 static struct hid_report *
76 hiddev_lookup_report(struct hid_device *hid, struct hiddev_report_info *rinfo)
77 {
78 	unsigned int flags = rinfo->report_id & ~HID_REPORT_ID_MASK;
79 	unsigned int rid = rinfo->report_id & HID_REPORT_ID_MASK;
80 	struct hid_report_enum *report_enum;
81 	struct hid_report *report;
82 	struct list_head *list;
83 
84 	if (rinfo->report_type < HID_REPORT_TYPE_MIN ||
85 	    rinfo->report_type > HID_REPORT_TYPE_MAX)
86 		return NULL;
87 
88 	report_enum = hid->report_enum +
89 		(rinfo->report_type - HID_REPORT_TYPE_MIN);
90 
91 	switch (flags) {
92 	case 0: /* Nothing to do -- report_id is already set correctly */
93 		break;
94 
95 	case HID_REPORT_ID_FIRST:
96 		if (list_empty(&report_enum->report_list))
97 			return NULL;
98 
99 		list = report_enum->report_list.next;
100 		report = list_entry(list, struct hid_report, list);
101 		rinfo->report_id = report->id;
102 		break;
103 
104 	case HID_REPORT_ID_NEXT:
105 		report = report_enum->report_id_hash[rid];
106 		if (!report)
107 			return NULL;
108 
109 		list = report->list.next;
110 		if (list == &report_enum->report_list)
111 			return NULL;
112 
113 		report = list_entry(list, struct hid_report, list);
114 		rinfo->report_id = report->id;
115 		break;
116 
117 	default:
118 		return NULL;
119 	}
120 
121 	return report_enum->report_id_hash[rinfo->report_id];
122 }
123 
124 /*
125  * Perform an exhaustive search of the report table for a usage, given its
126  * type and usage id.
127  */
128 static struct hid_field *
129 hiddev_lookup_usage(struct hid_device *hid, struct hiddev_usage_ref *uref)
130 {
131 	int i, j;
132 	struct hid_report *report;
133 	struct hid_report_enum *report_enum;
134 	struct hid_field *field;
135 
136 	if (uref->report_type < HID_REPORT_TYPE_MIN ||
137 	    uref->report_type > HID_REPORT_TYPE_MAX)
138 		return NULL;
139 
140 	report_enum = hid->report_enum +
141 		(uref->report_type - HID_REPORT_TYPE_MIN);
142 
143 	list_for_each_entry(report, &report_enum->report_list, list) {
144 		for (i = 0; i < report->maxfield; i++) {
145 			field = report->field[i];
146 			for (j = 0; j < field->maxusage; j++) {
147 				if (field->usage[j].hid == uref->usage_code) {
148 					uref->report_id = report->id;
149 					uref->field_index = i;
150 					uref->usage_index = j;
151 					return field;
152 				}
153 			}
154 		}
155 	}
156 
157 	return NULL;
158 }
159 
160 static void hiddev_send_event(struct hid_device *hid,
161 			      struct hiddev_usage_ref *uref)
162 {
163 	struct hiddev *hiddev = hid->hiddev;
164 	struct hiddev_list *list;
165 	unsigned long flags;
166 
167 	spin_lock_irqsave(&hiddev->list_lock, flags);
168 	list_for_each_entry(list, &hiddev->list, node) {
169 		if (uref->field_index != HID_FIELD_INDEX_NONE ||
170 		    (list->flags & HIDDEV_FLAG_REPORT) != 0) {
171 			list->buffer[list->head] = *uref;
172 			list->head = (list->head + 1) &
173 				(HIDDEV_BUFFER_SIZE - 1);
174 			kill_fasync(&list->fasync, SIGIO, POLL_IN);
175 		}
176 	}
177 	spin_unlock_irqrestore(&hiddev->list_lock, flags);
178 
179 	wake_up_interruptible(&hiddev->wait);
180 }
181 
182 /*
183  * This is where hid.c calls into hiddev to pass an event that occurred over
184  * the interrupt pipe
185  */
186 void hiddev_hid_event(struct hid_device *hid, struct hid_field *field,
187 		      struct hid_usage *usage, __s32 value)
188 {
189 	unsigned type = field->report_type;
190 	struct hiddev_usage_ref uref;
191 
192 	uref.report_type =
193 	  (type == HID_INPUT_REPORT) ? HID_REPORT_TYPE_INPUT :
194 	  ((type == HID_OUTPUT_REPORT) ? HID_REPORT_TYPE_OUTPUT :
195 	   ((type == HID_FEATURE_REPORT) ? HID_REPORT_TYPE_FEATURE : 0));
196 	uref.report_id = field->report->id;
197 	uref.field_index = field->index;
198 	uref.usage_index = (usage - field->usage);
199 	uref.usage_code = usage->hid;
200 	uref.value = value;
201 
202 	hiddev_send_event(hid, &uref);
203 }
204 EXPORT_SYMBOL_GPL(hiddev_hid_event);
205 
206 void hiddev_report_event(struct hid_device *hid, struct hid_report *report)
207 {
208 	unsigned type = report->type;
209 	struct hiddev_usage_ref uref;
210 
211 	memset(&uref, 0, sizeof(uref));
212 	uref.report_type =
213 	  (type == HID_INPUT_REPORT) ? HID_REPORT_TYPE_INPUT :
214 	  ((type == HID_OUTPUT_REPORT) ? HID_REPORT_TYPE_OUTPUT :
215 	   ((type == HID_FEATURE_REPORT) ? HID_REPORT_TYPE_FEATURE : 0));
216 	uref.report_id = report->id;
217 	uref.field_index = HID_FIELD_INDEX_NONE;
218 
219 	hiddev_send_event(hid, &uref);
220 }
221 
222 /*
223  * fasync file op
224  */
225 static int hiddev_fasync(int fd, struct file *file, int on)
226 {
227 	struct hiddev_list *list = file->private_data;
228 
229 	return fasync_helper(fd, file, on, &list->fasync);
230 }
231 
232 
233 /*
234  * release file op
235  */
236 static int hiddev_release(struct inode * inode, struct file * file)
237 {
238 	struct hiddev_list *list = file->private_data;
239 	unsigned long flags;
240 
241 	spin_lock_irqsave(&list->hiddev->list_lock, flags);
242 	list_del(&list->node);
243 	spin_unlock_irqrestore(&list->hiddev->list_lock, flags);
244 
245 	if (!--list->hiddev->open) {
246 		if (list->hiddev->exist) {
247 			usbhid_close(list->hiddev->hid);
248 			usbhid_put_power(list->hiddev->hid);
249 		} else {
250 			kfree(list->hiddev);
251 		}
252 	}
253 
254 	kfree(list);
255 
256 	return 0;
257 }
258 
259 /*
260  * open file op
261  */
262 static int hiddev_open(struct inode *inode, struct file *file)
263 {
264 	struct hiddev_list *list;
265 	struct usb_interface *intf;
266 	struct hid_device *hid;
267 	struct hiddev *hiddev;
268 	int res;
269 
270 	intf = usbhid_find_interface(iminor(inode));
271 	if (!intf)
272 		return -ENODEV;
273 	hid = usb_get_intfdata(intf);
274 	hiddev = hid->hiddev;
275 
276 	if (!(list = kzalloc(sizeof(struct hiddev_list), GFP_KERNEL)))
277 		return -ENOMEM;
278 	mutex_init(&list->thread_lock);
279 	list->hiddev = hiddev;
280 	file->private_data = list;
281 
282 	/*
283 	 * no need for locking because the USB major number
284 	 * is shared which usbcore guards against disconnect
285 	 */
286 	if (list->hiddev->exist) {
287 		if (!list->hiddev->open++) {
288 			res = usbhid_open(hiddev->hid);
289 			if (res < 0) {
290 				res = -EIO;
291 				goto bail;
292 			}
293 		}
294 	} else {
295 		res = -ENODEV;
296 		goto bail;
297 	}
298 
299 	spin_lock_irq(&list->hiddev->list_lock);
300 	list_add_tail(&list->node, &hiddev->list);
301 	spin_unlock_irq(&list->hiddev->list_lock);
302 
303 	if (!list->hiddev->open++)
304 		if (list->hiddev->exist) {
305 			struct hid_device *hid = hiddev->hid;
306 			res = usbhid_get_power(hid);
307 			if (res < 0) {
308 				res = -EIO;
309 				goto bail;
310 			}
311 			usbhid_open(hid);
312 		}
313 	return 0;
314 bail:
315 	file->private_data = NULL;
316 	kfree(list);
317 	return res;
318 }
319 
320 /*
321  * "write" file op
322  */
323 static ssize_t hiddev_write(struct file * file, const char __user * buffer, size_t count, loff_t *ppos)
324 {
325 	return -EINVAL;
326 }
327 
328 /*
329  * "read" file op
330  */
331 static ssize_t hiddev_read(struct file * file, char __user * buffer, size_t count, loff_t *ppos)
332 {
333 	DEFINE_WAIT(wait);
334 	struct hiddev_list *list = file->private_data;
335 	int event_size;
336 	int retval;
337 
338 	event_size = ((list->flags & HIDDEV_FLAG_UREF) != 0) ?
339 		sizeof(struct hiddev_usage_ref) : sizeof(struct hiddev_event);
340 
341 	if (count < event_size)
342 		return 0;
343 
344 	/* lock against other threads */
345 	retval = mutex_lock_interruptible(&list->thread_lock);
346 	if (retval)
347 		return -ERESTARTSYS;
348 
349 	while (retval == 0) {
350 		if (list->head == list->tail) {
351 			prepare_to_wait(&list->hiddev->wait, &wait, TASK_INTERRUPTIBLE);
352 
353 			while (list->head == list->tail) {
354 				if (file->f_flags & O_NONBLOCK) {
355 					retval = -EAGAIN;
356 					break;
357 				}
358 				if (signal_pending(current)) {
359 					retval = -ERESTARTSYS;
360 					break;
361 				}
362 				if (!list->hiddev->exist) {
363 					retval = -EIO;
364 					break;
365 				}
366 
367 				/* let O_NONBLOCK tasks run */
368 				mutex_unlock(&list->thread_lock);
369 				schedule();
370 				if (mutex_lock_interruptible(&list->thread_lock))
371 					return -EINTR;
372 				set_current_state(TASK_INTERRUPTIBLE);
373 			}
374 			finish_wait(&list->hiddev->wait, &wait);
375 
376 		}
377 
378 		if (retval) {
379 			mutex_unlock(&list->thread_lock);
380 			return retval;
381 		}
382 
383 
384 		while (list->head != list->tail &&
385 		       retval + event_size <= count) {
386 			if ((list->flags & HIDDEV_FLAG_UREF) == 0) {
387 				if (list->buffer[list->tail].field_index != HID_FIELD_INDEX_NONE) {
388 					struct hiddev_event event;
389 
390 					event.hid = list->buffer[list->tail].usage_code;
391 					event.value = list->buffer[list->tail].value;
392 					if (copy_to_user(buffer + retval, &event, sizeof(struct hiddev_event))) {
393 						mutex_unlock(&list->thread_lock);
394 						return -EFAULT;
395 					}
396 					retval += sizeof(struct hiddev_event);
397 				}
398 			} else {
399 				if (list->buffer[list->tail].field_index != HID_FIELD_INDEX_NONE ||
400 				    (list->flags & HIDDEV_FLAG_REPORT) != 0) {
401 
402 					if (copy_to_user(buffer + retval, list->buffer + list->tail, sizeof(struct hiddev_usage_ref))) {
403 						mutex_unlock(&list->thread_lock);
404 						return -EFAULT;
405 					}
406 					retval += sizeof(struct hiddev_usage_ref);
407 				}
408 			}
409 			list->tail = (list->tail + 1) & (HIDDEV_BUFFER_SIZE - 1);
410 		}
411 
412 	}
413 	mutex_unlock(&list->thread_lock);
414 
415 	return retval;
416 }
417 
418 /*
419  * "poll" file op
420  * No kernel lock - fine
421  */
422 static unsigned int hiddev_poll(struct file *file, poll_table *wait)
423 {
424 	struct hiddev_list *list = file->private_data;
425 
426 	poll_wait(file, &list->hiddev->wait, wait);
427 	if (list->head != list->tail)
428 		return POLLIN | POLLRDNORM;
429 	if (!list->hiddev->exist)
430 		return POLLERR | POLLHUP;
431 	return 0;
432 }
433 
434 /*
435  * "ioctl" file op
436  */
437 static noinline int hiddev_ioctl_usage(struct hiddev *hiddev, unsigned int cmd, void __user *user_arg)
438 {
439 	struct hid_device *hid = hiddev->hid;
440 	struct hiddev_report_info rinfo;
441 	struct hiddev_usage_ref_multi *uref_multi = NULL;
442 	struct hiddev_usage_ref *uref;
443 	struct hid_report *report;
444 	struct hid_field *field;
445 	int i;
446 
447 	uref_multi = kmalloc(sizeof(struct hiddev_usage_ref_multi), GFP_KERNEL);
448 	if (!uref_multi)
449 		return -ENOMEM;
450 	uref = &uref_multi->uref;
451 	if (cmd == HIDIOCGUSAGES || cmd == HIDIOCSUSAGES) {
452 		if (copy_from_user(uref_multi, user_arg,
453 				   sizeof(*uref_multi)))
454 			goto fault;
455 	} else {
456 		if (copy_from_user(uref, user_arg, sizeof(*uref)))
457 			goto fault;
458 	}
459 
460 	switch (cmd) {
461 	case HIDIOCGUCODE:
462 		rinfo.report_type = uref->report_type;
463 		rinfo.report_id = uref->report_id;
464 		if ((report = hiddev_lookup_report(hid, &rinfo)) == NULL)
465 			goto inval;
466 
467 		if (uref->field_index >= report->maxfield)
468 			goto inval;
469 
470 		field = report->field[uref->field_index];
471 		if (uref->usage_index >= field->maxusage)
472 			goto inval;
473 
474 		uref->usage_code = field->usage[uref->usage_index].hid;
475 
476 		if (copy_to_user(user_arg, uref, sizeof(*uref)))
477 			goto fault;
478 
479 		goto goodreturn;
480 
481 	default:
482 		if (cmd != HIDIOCGUSAGE &&
483 		    cmd != HIDIOCGUSAGES &&
484 		    uref->report_type == HID_REPORT_TYPE_INPUT)
485 			goto inval;
486 
487 		if (uref->report_id == HID_REPORT_ID_UNKNOWN) {
488 			field = hiddev_lookup_usage(hid, uref);
489 			if (field == NULL)
490 				goto inval;
491 		} else {
492 			rinfo.report_type = uref->report_type;
493 			rinfo.report_id = uref->report_id;
494 			if ((report = hiddev_lookup_report(hid, &rinfo)) == NULL)
495 				goto inval;
496 
497 			if (uref->field_index >= report->maxfield)
498 				goto inval;
499 
500 			field = report->field[uref->field_index];
501 
502 			if (cmd == HIDIOCGCOLLECTIONINDEX) {
503 				if (uref->usage_index >= field->maxusage)
504 					goto inval;
505 			} else if (uref->usage_index >= field->report_count)
506 				goto inval;
507 
508 			else if ((cmd == HIDIOCGUSAGES || cmd == HIDIOCSUSAGES) &&
509 				 (uref_multi->num_values > HID_MAX_MULTI_USAGES ||
510 				  uref->usage_index + uref_multi->num_values > field->report_count))
511 				goto inval;
512 			}
513 
514 		switch (cmd) {
515 		case HIDIOCGUSAGE:
516 			uref->value = field->value[uref->usage_index];
517 			if (copy_to_user(user_arg, uref, sizeof(*uref)))
518 				goto fault;
519 			goto goodreturn;
520 
521 		case HIDIOCSUSAGE:
522 			field->value[uref->usage_index] = uref->value;
523 			goto goodreturn;
524 
525 		case HIDIOCGCOLLECTIONINDEX:
526 			i = field->usage[uref->usage_index].collection_index;
527 			kfree(uref_multi);
528 			return i;
529 		case HIDIOCGUSAGES:
530 			for (i = 0; i < uref_multi->num_values; i++)
531 				uref_multi->values[i] =
532 				    field->value[uref->usage_index + i];
533 			if (copy_to_user(user_arg, uref_multi,
534 					 sizeof(*uref_multi)))
535 				goto fault;
536 			goto goodreturn;
537 		case HIDIOCSUSAGES:
538 			for (i = 0; i < uref_multi->num_values; i++)
539 				field->value[uref->usage_index + i] =
540 				    uref_multi->values[i];
541 			goto goodreturn;
542 		}
543 
544 goodreturn:
545 		kfree(uref_multi);
546 		return 0;
547 fault:
548 		kfree(uref_multi);
549 		return -EFAULT;
550 inval:
551 		kfree(uref_multi);
552 		return -EINVAL;
553 	}
554 }
555 
556 static noinline int hiddev_ioctl_string(struct hiddev *hiddev, unsigned int cmd, void __user *user_arg)
557 {
558 	struct hid_device *hid = hiddev->hid;
559 	struct usb_device *dev = hid_to_usb_dev(hid);
560 	int idx, len;
561 	char *buf;
562 
563 	if (get_user(idx, (int __user *)user_arg))
564 		return -EFAULT;
565 
566 	if ((buf = kmalloc(HID_STRING_SIZE, GFP_KERNEL)) == NULL)
567 		return -ENOMEM;
568 
569 	if ((len = usb_string(dev, idx, buf, HID_STRING_SIZE-1)) < 0) {
570 		kfree(buf);
571 		return -EINVAL;
572 	}
573 
574 	if (copy_to_user(user_arg+sizeof(int), buf, len+1)) {
575 		kfree(buf);
576 		return -EFAULT;
577 	}
578 
579 	kfree(buf);
580 
581 	return len;
582 }
583 
584 static long hiddev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
585 {
586 	struct hiddev_list *list = file->private_data;
587 	struct hiddev *hiddev = list->hiddev;
588 	struct hid_device *hid;
589 	struct hiddev_collection_info cinfo;
590 	struct hiddev_report_info rinfo;
591 	struct hiddev_field_info finfo;
592 	struct hiddev_devinfo dinfo;
593 	struct hid_report *report;
594 	struct hid_field *field;
595 	void __user *user_arg = (void __user *)arg;
596 	int i, r = -EINVAL;
597 
598 	/* Called without BKL by compat methods so no BKL taken */
599 
600 	mutex_lock(&hiddev->existancelock);
601 	if (!hiddev->exist) {
602 		r = -ENODEV;
603 		goto ret_unlock;
604 	}
605 
606 	hid = hiddev->hid;
607 
608 	switch (cmd) {
609 
610 	case HIDIOCGVERSION:
611 		r = put_user(HID_VERSION, (int __user *)arg) ?
612 			-EFAULT : 0;
613 		break;
614 
615 	case HIDIOCAPPLICATION:
616 		if (arg < 0 || arg >= hid->maxapplication)
617 			break;
618 
619 		for (i = 0; i < hid->maxcollection; i++)
620 			if (hid->collection[i].type ==
621 			    HID_COLLECTION_APPLICATION && arg-- == 0)
622 				break;
623 
624 		if (i < hid->maxcollection)
625 			r = hid->collection[i].usage;
626 		break;
627 
628 	case HIDIOCGDEVINFO:
629 		{
630 			struct usb_device *dev = hid_to_usb_dev(hid);
631 			struct usbhid_device *usbhid = hid->driver_data;
632 
633 			dinfo.bustype = BUS_USB;
634 			dinfo.busnum = dev->bus->busnum;
635 			dinfo.devnum = dev->devnum;
636 			dinfo.ifnum = usbhid->ifnum;
637 			dinfo.vendor = le16_to_cpu(dev->descriptor.idVendor);
638 			dinfo.product = le16_to_cpu(dev->descriptor.idProduct);
639 			dinfo.version = le16_to_cpu(dev->descriptor.bcdDevice);
640 			dinfo.num_applications = hid->maxapplication;
641 
642 			r = copy_to_user(user_arg, &dinfo, sizeof(dinfo)) ?
643 				-EFAULT : 0;
644 			break;
645 		}
646 
647 	case HIDIOCGFLAG:
648 		r = put_user(list->flags, (int __user *)arg) ?
649 			-EFAULT : 0;
650 		break;
651 
652 	case HIDIOCSFLAG:
653 		{
654 			int newflags;
655 
656 			if (get_user(newflags, (int __user *)arg)) {
657 				r = -EFAULT;
658 				break;
659 			}
660 
661 			if ((newflags & ~HIDDEV_FLAGS) != 0 ||
662 			    ((newflags & HIDDEV_FLAG_REPORT) != 0 &&
663 			     (newflags & HIDDEV_FLAG_UREF) == 0))
664 				break;
665 
666 			list->flags = newflags;
667 
668 			r = 0;
669 			break;
670 		}
671 
672 	case HIDIOCGSTRING:
673 		r = hiddev_ioctl_string(hiddev, cmd, user_arg);
674 		break;
675 
676 	case HIDIOCINITREPORT:
677 		usbhid_init_reports(hid);
678 		r = 0;
679 		break;
680 
681 	case HIDIOCGREPORT:
682 		if (copy_from_user(&rinfo, user_arg, sizeof(rinfo))) {
683 			r = -EFAULT;
684 			break;
685 		}
686 
687 		if (rinfo.report_type == HID_REPORT_TYPE_OUTPUT)
688 			break;
689 
690 		report = hiddev_lookup_report(hid, &rinfo);
691 		if (report == NULL)
692 			break;
693 
694 		usbhid_submit_report(hid, report, USB_DIR_IN);
695 		usbhid_wait_io(hid);
696 
697 		r = 0;
698 		break;
699 
700 	case HIDIOCSREPORT:
701 		if (copy_from_user(&rinfo, user_arg, sizeof(rinfo))) {
702 			r = -EFAULT;
703 			break;
704 		}
705 
706 		if (rinfo.report_type == HID_REPORT_TYPE_INPUT)
707 			break;
708 
709 		report = hiddev_lookup_report(hid, &rinfo);
710 		if (report == NULL)
711 			break;
712 
713 		usbhid_submit_report(hid, report, USB_DIR_OUT);
714 		usbhid_wait_io(hid);
715 
716 		r = 0;
717 		break;
718 
719 	case HIDIOCGREPORTINFO:
720 		if (copy_from_user(&rinfo, user_arg, sizeof(rinfo))) {
721 			r = -EFAULT;
722 			break;
723 		}
724 
725 		report = hiddev_lookup_report(hid, &rinfo);
726 		if (report == NULL)
727 			break;
728 
729 		rinfo.num_fields = report->maxfield;
730 
731 		r = copy_to_user(user_arg, &rinfo, sizeof(rinfo)) ?
732 			-EFAULT : 0;
733 		break;
734 
735 	case HIDIOCGFIELDINFO:
736 		if (copy_from_user(&finfo, user_arg, sizeof(finfo))) {
737 			r = -EFAULT;
738 			break;
739 		}
740 
741 		rinfo.report_type = finfo.report_type;
742 		rinfo.report_id = finfo.report_id;
743 
744 		report = hiddev_lookup_report(hid, &rinfo);
745 		if (report == NULL)
746 			break;
747 
748 		if (finfo.field_index >= report->maxfield)
749 			break;
750 
751 		field = report->field[finfo.field_index];
752 		memset(&finfo, 0, sizeof(finfo));
753 		finfo.report_type = rinfo.report_type;
754 		finfo.report_id = rinfo.report_id;
755 		finfo.field_index = field->report_count - 1;
756 		finfo.maxusage = field->maxusage;
757 		finfo.flags = field->flags;
758 		finfo.physical = field->physical;
759 		finfo.logical = field->logical;
760 		finfo.application = field->application;
761 		finfo.logical_minimum = field->logical_minimum;
762 		finfo.logical_maximum = field->logical_maximum;
763 		finfo.physical_minimum = field->physical_minimum;
764 		finfo.physical_maximum = field->physical_maximum;
765 		finfo.unit_exponent = field->unit_exponent;
766 		finfo.unit = field->unit;
767 
768 		r = copy_to_user(user_arg, &finfo, sizeof(finfo)) ?
769 			-EFAULT : 0;
770 		break;
771 
772 	case HIDIOCGUCODE:
773 		/* fall through */
774 	case HIDIOCGUSAGE:
775 	case HIDIOCSUSAGE:
776 	case HIDIOCGUSAGES:
777 	case HIDIOCSUSAGES:
778 	case HIDIOCGCOLLECTIONINDEX:
779 		r = hiddev_ioctl_usage(hiddev, cmd, user_arg);
780 		break;
781 
782 	case HIDIOCGCOLLECTIONINFO:
783 		if (copy_from_user(&cinfo, user_arg, sizeof(cinfo))) {
784 			r = -EFAULT;
785 			break;
786 		}
787 
788 		if (cinfo.index >= hid->maxcollection)
789 			break;
790 
791 		cinfo.type = hid->collection[cinfo.index].type;
792 		cinfo.usage = hid->collection[cinfo.index].usage;
793 		cinfo.level = hid->collection[cinfo.index].level;
794 
795 		r = copy_to_user(user_arg, &cinfo, sizeof(cinfo)) ?
796 			-EFAULT : 0;
797 		break;
798 
799 	default:
800 		if (_IOC_TYPE(cmd) != 'H' || _IOC_DIR(cmd) != _IOC_READ)
801 			break;
802 
803 		if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGNAME(0))) {
804 			int len;
805 
806 			if (!hid->name) {
807 				r = 0;
808 				break;
809 			}
810 
811 			len = strlen(hid->name) + 1;
812 			if (len > _IOC_SIZE(cmd))
813 				 len = _IOC_SIZE(cmd);
814 			r = copy_to_user(user_arg, hid->name, len) ?
815 				-EFAULT : len;
816 			break;
817 		}
818 
819 		if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGPHYS(0))) {
820 			int len;
821 
822 			if (!hid->phys) {
823 				r = 0;
824 				break;
825 			}
826 
827 			len = strlen(hid->phys) + 1;
828 			if (len > _IOC_SIZE(cmd))
829 				len = _IOC_SIZE(cmd);
830 			r = copy_to_user(user_arg, hid->phys, len) ?
831 				-EFAULT : len;
832 			break;
833 		}
834 	}
835 
836 ret_unlock:
837 	mutex_unlock(&hiddev->existancelock);
838 	return r;
839 }
840 
841 #ifdef CONFIG_COMPAT
842 static long hiddev_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
843 {
844 	return hiddev_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
845 }
846 #endif
847 
848 static const struct file_operations hiddev_fops = {
849 	.owner =	THIS_MODULE,
850 	.read =		hiddev_read,
851 	.write =	hiddev_write,
852 	.poll =		hiddev_poll,
853 	.open =		hiddev_open,
854 	.release =	hiddev_release,
855 	.unlocked_ioctl =	hiddev_ioctl,
856 	.fasync =	hiddev_fasync,
857 #ifdef CONFIG_COMPAT
858 	.compat_ioctl	= hiddev_compat_ioctl,
859 #endif
860 	.llseek		= noop_llseek,
861 };
862 
863 static char *hiddev_devnode(struct device *dev, mode_t *mode)
864 {
865 	return kasprintf(GFP_KERNEL, "usb/%s", dev_name(dev));
866 }
867 
868 static struct usb_class_driver hiddev_class = {
869 	.name =		"hiddev%d",
870 	.devnode =	hiddev_devnode,
871 	.fops =		&hiddev_fops,
872 	.minor_base =	HIDDEV_MINOR_BASE,
873 };
874 
875 /*
876  * This is where hid.c calls us to connect a hid device to the hiddev driver
877  */
878 int hiddev_connect(struct hid_device *hid, unsigned int force)
879 {
880 	struct hiddev *hiddev;
881 	struct usbhid_device *usbhid = hid->driver_data;
882 	int retval;
883 
884 	if (!force) {
885 		unsigned int i;
886 		for (i = 0; i < hid->maxcollection; i++)
887 			if (hid->collection[i].type ==
888 			    HID_COLLECTION_APPLICATION &&
889 			    !IS_INPUT_APPLICATION(hid->collection[i].usage))
890 				break;
891 
892 		if (i == hid->maxcollection)
893 			return -1;
894 	}
895 
896 	if (!(hiddev = kzalloc(sizeof(struct hiddev), GFP_KERNEL)))
897 		return -1;
898 
899 	init_waitqueue_head(&hiddev->wait);
900 	INIT_LIST_HEAD(&hiddev->list);
901 	spin_lock_init(&hiddev->list_lock);
902 	mutex_init(&hiddev->existancelock);
903 	hid->hiddev = hiddev;
904 	hiddev->hid = hid;
905 	hiddev->exist = 1;
906 	retval = usb_register_dev(usbhid->intf, &hiddev_class);
907 	if (retval) {
908 		hid_err(hid, "Not able to get a minor for this device\n");
909 		hid->hiddev = NULL;
910 		kfree(hiddev);
911 		return -1;
912 	}
913 	return 0;
914 }
915 
916 /*
917  * This is where hid.c calls us to disconnect a hiddev device from the
918  * corresponding hid device (usually because the usb device has disconnected)
919  */
920 static struct usb_class_driver hiddev_class;
921 void hiddev_disconnect(struct hid_device *hid)
922 {
923 	struct hiddev *hiddev = hid->hiddev;
924 	struct usbhid_device *usbhid = hid->driver_data;
925 
926 	mutex_lock(&hiddev->existancelock);
927 	hiddev->exist = 0;
928 	mutex_unlock(&hiddev->existancelock);
929 
930 	usb_deregister_dev(usbhid->intf, &hiddev_class);
931 
932 	if (hiddev->open) {
933 		usbhid_close(hiddev->hid);
934 		wake_up_interruptible(&hiddev->wait);
935 	} else {
936 		kfree(hiddev);
937 	}
938 }
939