xref: /linux/drivers/hid/usbhid/hiddev.c (revision fd7a253311412b3fc7c85586552c90eca61e7d23)
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 	int retval;
231 	struct hiddev_list *list = file->private_data;
232 
233 	retval = fasync_helper(fd, file, on, &list->fasync);
234 
235 	return retval < 0 ? retval : 0;
236 }
237 
238 
239 /*
240  * release file op
241  */
242 static int hiddev_release(struct inode * inode, struct file * file)
243 {
244 	struct hiddev_list *list = file->private_data;
245 	unsigned long flags;
246 
247 	spin_lock_irqsave(&list->hiddev->list_lock, flags);
248 	list_del(&list->node);
249 	spin_unlock_irqrestore(&list->hiddev->list_lock, flags);
250 
251 	if (!--list->hiddev->open) {
252 		if (list->hiddev->exist)
253 			usbhid_close(list->hiddev->hid);
254 		else
255 			kfree(list->hiddev);
256 	}
257 
258 	kfree(list);
259 
260 	return 0;
261 }
262 
263 /*
264  * open file op
265  */
266 static int hiddev_open(struct inode *inode, struct file *file)
267 {
268 	struct hiddev_list *list;
269 	int res;
270 
271 	int i = iminor(inode) - HIDDEV_MINOR_BASE;
272 
273 	if (i >= HIDDEV_MINORS || i < 0 || !hiddev_table[i])
274 		return -ENODEV;
275 
276 	if (!(list = kzalloc(sizeof(struct hiddev_list), GFP_KERNEL)))
277 		return -ENOMEM;
278 	mutex_init(&list->thread_lock);
279 
280 	list->hiddev = hiddev_table[i];
281 
282 
283 	file->private_data = list;
284 
285 	/*
286 	 * no need for locking because the USB major number
287 	 * is shared which usbcore guards against disconnect
288 	 */
289 	if (list->hiddev->exist) {
290 		if (!list->hiddev->open++) {
291 			res = usbhid_open(hiddev_table[i]->hid);
292 			if (res < 0) {
293 				res = -EIO;
294 				goto bail;
295 			}
296 		}
297 	} else {
298 		res = -ENODEV;
299 		goto bail;
300 	}
301 
302 	spin_lock_irq(&list->hiddev->list_lock);
303 	list_add_tail(&list->node, &hiddev_table[i]->list);
304 	spin_unlock_irq(&list->hiddev->list_lock);
305 
306 	return 0;
307 bail:
308 	file->private_data = NULL;
309 	kfree(list->hiddev);
310 	return res;
311 }
312 
313 /*
314  * "write" file op
315  */
316 static ssize_t hiddev_write(struct file * file, const char __user * buffer, size_t count, loff_t *ppos)
317 {
318 	return -EINVAL;
319 }
320 
321 /*
322  * "read" file op
323  */
324 static ssize_t hiddev_read(struct file * file, char __user * buffer, size_t count, loff_t *ppos)
325 {
326 	DECLARE_WAITQUEUE(wait, current);
327 	struct hiddev_list *list = file->private_data;
328 	int event_size;
329 	int retval;
330 
331 	event_size = ((list->flags & HIDDEV_FLAG_UREF) != 0) ?
332 		sizeof(struct hiddev_usage_ref) : sizeof(struct hiddev_event);
333 
334 	if (count < event_size)
335 		return 0;
336 
337 	/* lock against other threads */
338 	retval = mutex_lock_interruptible(&list->thread_lock);
339 	if (retval)
340 		return -ERESTARTSYS;
341 
342 	while (retval == 0) {
343 		if (list->head == list->tail) {
344 			prepare_to_wait(&list->hiddev->wait, &wait, TASK_INTERRUPTIBLE);
345 
346 			while (list->head == list->tail) {
347 				if (file->f_flags & O_NONBLOCK) {
348 					retval = -EAGAIN;
349 					break;
350 				}
351 				if (signal_pending(current)) {
352 					retval = -ERESTARTSYS;
353 					break;
354 				}
355 				if (!list->hiddev->exist) {
356 					retval = -EIO;
357 					break;
358 				}
359 
360 				/* let O_NONBLOCK tasks run */
361 				mutex_unlock(&list->thread_lock);
362 				schedule();
363 				if (mutex_lock_interruptible(&list->thread_lock))
364 					return -EINTR;
365 				set_current_state(TASK_INTERRUPTIBLE);
366 			}
367 			finish_wait(&list->hiddev->wait, &wait);
368 
369 		}
370 
371 		if (retval) {
372 			mutex_unlock(&list->thread_lock);
373 			return retval;
374 		}
375 
376 
377 		while (list->head != list->tail &&
378 		       retval + event_size <= count) {
379 			if ((list->flags & HIDDEV_FLAG_UREF) == 0) {
380 				if (list->buffer[list->tail].field_index != HID_FIELD_INDEX_NONE) {
381 					struct hiddev_event event;
382 
383 					event.hid = list->buffer[list->tail].usage_code;
384 					event.value = list->buffer[list->tail].value;
385 					if (copy_to_user(buffer + retval, &event, sizeof(struct hiddev_event))) {
386 						mutex_unlock(&list->thread_lock);
387 						return -EFAULT;
388 					}
389 					retval += sizeof(struct hiddev_event);
390 				}
391 			} else {
392 				if (list->buffer[list->tail].field_index != HID_FIELD_INDEX_NONE ||
393 				    (list->flags & HIDDEV_FLAG_REPORT) != 0) {
394 
395 					if (copy_to_user(buffer + retval, list->buffer + list->tail, sizeof(struct hiddev_usage_ref))) {
396 						mutex_unlock(&list->thread_lock);
397 						return -EFAULT;
398 					}
399 					retval += sizeof(struct hiddev_usage_ref);
400 				}
401 			}
402 			list->tail = (list->tail + 1) & (HIDDEV_BUFFER_SIZE - 1);
403 		}
404 
405 	}
406 	mutex_unlock(&list->thread_lock);
407 
408 	return retval;
409 }
410 
411 /*
412  * "poll" file op
413  * No kernel lock - fine
414  */
415 static unsigned int hiddev_poll(struct file *file, poll_table *wait)
416 {
417 	struct hiddev_list *list = file->private_data;
418 
419 	poll_wait(file, &list->hiddev->wait, wait);
420 	if (list->head != list->tail)
421 		return POLLIN | POLLRDNORM;
422 	if (!list->hiddev->exist)
423 		return POLLERR | POLLHUP;
424 	return 0;
425 }
426 
427 /*
428  * "ioctl" file op
429  */
430 static noinline int hiddev_ioctl_usage(struct hiddev *hiddev, unsigned int cmd, void __user *user_arg)
431 {
432 	struct hid_device *hid = hiddev->hid;
433 	struct hiddev_report_info rinfo;
434 	struct hiddev_usage_ref_multi *uref_multi = NULL;
435 	struct hiddev_usage_ref *uref;
436 	struct hid_report *report;
437 	struct hid_field *field;
438 	int i;
439 
440 	uref_multi = kmalloc(sizeof(struct hiddev_usage_ref_multi), GFP_KERNEL);
441 	if (!uref_multi)
442 		return -ENOMEM;
443 	lock_kernel();
444 	uref = &uref_multi->uref;
445 	if (cmd == HIDIOCGUSAGES || cmd == HIDIOCSUSAGES) {
446 		if (copy_from_user(uref_multi, user_arg,
447 				   sizeof(*uref_multi)))
448 			goto fault;
449 	} else {
450 		if (copy_from_user(uref, user_arg, sizeof(*uref)))
451 			goto fault;
452 	}
453 
454 	switch (cmd) {
455 	case HIDIOCGUCODE:
456 		rinfo.report_type = uref->report_type;
457 		rinfo.report_id = uref->report_id;
458 		if ((report = hiddev_lookup_report(hid, &rinfo)) == NULL)
459 			goto inval;
460 
461 		if (uref->field_index >= report->maxfield)
462 			goto inval;
463 
464 		field = report->field[uref->field_index];
465 		if (uref->usage_index >= field->maxusage)
466 			goto inval;
467 
468 		uref->usage_code = field->usage[uref->usage_index].hid;
469 
470 		if (copy_to_user(user_arg, uref, sizeof(*uref)))
471 			goto fault;
472 
473 		goto goodreturn;
474 
475 	default:
476 		if (cmd != HIDIOCGUSAGE &&
477 		    cmd != HIDIOCGUSAGES &&
478 		    uref->report_type == HID_REPORT_TYPE_INPUT)
479 			goto inval;
480 
481 		if (uref->report_id == HID_REPORT_ID_UNKNOWN) {
482 			field = hiddev_lookup_usage(hid, uref);
483 			if (field == NULL)
484 				goto inval;
485 		} else {
486 			rinfo.report_type = uref->report_type;
487 			rinfo.report_id = uref->report_id;
488 			if ((report = hiddev_lookup_report(hid, &rinfo)) == NULL)
489 				goto inval;
490 
491 			if (uref->field_index >= report->maxfield)
492 				goto inval;
493 
494 			field = report->field[uref->field_index];
495 
496 			if (cmd == HIDIOCGCOLLECTIONINDEX) {
497 				if (uref->usage_index >= field->maxusage)
498 					goto inval;
499 			} else if (uref->usage_index >= field->report_count)
500 				goto inval;
501 
502 			else if ((cmd == HIDIOCGUSAGES || cmd == HIDIOCSUSAGES) &&
503 				 (uref_multi->num_values > HID_MAX_MULTI_USAGES ||
504 				  uref->usage_index + uref_multi->num_values > field->report_count))
505 				goto inval;
506 			}
507 
508 		switch (cmd) {
509 		case HIDIOCGUSAGE:
510 			uref->value = field->value[uref->usage_index];
511 			if (copy_to_user(user_arg, uref, sizeof(*uref)))
512 				goto fault;
513 			goto goodreturn;
514 
515 		case HIDIOCSUSAGE:
516 			field->value[uref->usage_index] = uref->value;
517 			goto goodreturn;
518 
519 		case HIDIOCGCOLLECTIONINDEX:
520 			kfree(uref_multi);
521 			return field->usage[uref->usage_index].collection_index;
522 		case HIDIOCGUSAGES:
523 			for (i = 0; i < uref_multi->num_values; i++)
524 				uref_multi->values[i] =
525 				    field->value[uref->usage_index + i];
526 			if (copy_to_user(user_arg, uref_multi,
527 					 sizeof(*uref_multi)))
528 				goto fault;
529 			goto goodreturn;
530 		case HIDIOCSUSAGES:
531 			for (i = 0; i < uref_multi->num_values; i++)
532 				field->value[uref->usage_index + i] =
533 				    uref_multi->values[i];
534 			goto goodreturn;
535 		}
536 
537 goodreturn:
538 		unlock_kernel();
539 		kfree(uref_multi);
540 		return 0;
541 fault:
542 		unlock_kernel();
543 		kfree(uref_multi);
544 		return -EFAULT;
545 inval:
546 		unlock_kernel();
547 		kfree(uref_multi);
548 		return -EINVAL;
549 	}
550 }
551 
552 static noinline int hiddev_ioctl_string(struct hiddev *hiddev, unsigned int cmd, void __user *user_arg)
553 {
554 	struct hid_device *hid = hiddev->hid;
555 	struct usb_device *dev = hid_to_usb_dev(hid);
556 	int idx, len;
557 	char *buf;
558 
559 	if (get_user(idx, (int __user *)user_arg))
560 		return -EFAULT;
561 
562 	if ((buf = kmalloc(HID_STRING_SIZE, GFP_KERNEL)) == NULL)
563 		return -ENOMEM;
564 
565 	if ((len = usb_string(dev, idx, buf, HID_STRING_SIZE-1)) < 0) {
566 		kfree(buf);
567 		return -EINVAL;
568 	}
569 
570 	if (copy_to_user(user_arg+sizeof(int), buf, len+1)) {
571 		kfree(buf);
572 		return -EFAULT;
573 	}
574 
575 	kfree(buf);
576 
577 	return len;
578 }
579 
580 static long hiddev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
581 {
582 	struct hiddev_list *list = file->private_data;
583 	struct hiddev *hiddev = list->hiddev;
584 	struct hid_device *hid = hiddev->hid;
585 	struct usb_device *dev = hid_to_usb_dev(hid);
586 	struct hiddev_collection_info cinfo;
587 	struct hiddev_report_info rinfo;
588 	struct hiddev_field_info finfo;
589 	struct hiddev_devinfo dinfo;
590 	struct hid_report *report;
591 	struct hid_field *field;
592 	struct usbhid_device *usbhid = hid->driver_data;
593 	void __user *user_arg = (void __user *)arg;
594 	int i, r;
595 
596 	/* Called without BKL by compat methods so no BKL taken */
597 
598 	/* FIXME: Who or what stop this racing with a disconnect ?? */
599 	if (!hiddev->exist)
600 		return -EIO;
601 
602 	switch (cmd) {
603 
604 	case HIDIOCGVERSION:
605 		return put_user(HID_VERSION, (int __user *)arg);
606 
607 	case HIDIOCAPPLICATION:
608 		if (arg < 0 || arg >= hid->maxapplication)
609 			return -EINVAL;
610 
611 		for (i = 0; i < hid->maxcollection; i++)
612 			if (hid->collection[i].type ==
613 			    HID_COLLECTION_APPLICATION && arg-- == 0)
614 				break;
615 
616 		if (i == hid->maxcollection)
617 			return -EINVAL;
618 
619 		return hid->collection[i].usage;
620 
621 	case HIDIOCGDEVINFO:
622 		dinfo.bustype = BUS_USB;
623 		dinfo.busnum = dev->bus->busnum;
624 		dinfo.devnum = dev->devnum;
625 		dinfo.ifnum = usbhid->ifnum;
626 		dinfo.vendor = le16_to_cpu(dev->descriptor.idVendor);
627 		dinfo.product = le16_to_cpu(dev->descriptor.idProduct);
628 		dinfo.version = le16_to_cpu(dev->descriptor.bcdDevice);
629 		dinfo.num_applications = hid->maxapplication;
630 		if (copy_to_user(user_arg, &dinfo, sizeof(dinfo)))
631 			return -EFAULT;
632 
633 		return 0;
634 
635 	case HIDIOCGFLAG:
636 		if (put_user(list->flags, (int __user *)arg))
637 			return -EFAULT;
638 
639 		return 0;
640 
641 	case HIDIOCSFLAG:
642 		{
643 			int newflags;
644 			if (get_user(newflags, (int __user *)arg))
645 				return -EFAULT;
646 
647 			if ((newflags & ~HIDDEV_FLAGS) != 0 ||
648 			    ((newflags & HIDDEV_FLAG_REPORT) != 0 &&
649 			     (newflags & HIDDEV_FLAG_UREF) == 0))
650 				return -EINVAL;
651 
652 			list->flags = newflags;
653 
654 			return 0;
655 		}
656 
657 	case HIDIOCGSTRING:
658 		mutex_lock(&hiddev->existancelock);
659 		if (!hiddev->exist)
660 			r = hiddev_ioctl_string(hiddev, cmd, user_arg);
661 		else
662 			r = -ENODEV;
663 		mutex_unlock(&hiddev->existancelock);
664 		return r;
665 
666 	case HIDIOCINITREPORT:
667 		mutex_lock(&hiddev->existancelock);
668 		if (!hiddev->exist) {
669 			mutex_unlock(&hiddev->existancelock);
670 			return -ENODEV;
671 		}
672 		usbhid_init_reports(hid);
673 		mutex_unlock(&hiddev->existancelock);
674 
675 		return 0;
676 
677 	case HIDIOCGREPORT:
678 		if (copy_from_user(&rinfo, user_arg, sizeof(rinfo)))
679 			return -EFAULT;
680 
681 		if (rinfo.report_type == HID_REPORT_TYPE_OUTPUT)
682 			return -EINVAL;
683 
684 		if ((report = hiddev_lookup_report(hid, &rinfo)) == NULL)
685 			return -EINVAL;
686 
687 		mutex_lock(&hiddev->existancelock);
688 		if (hiddev->exist) {
689 			usbhid_submit_report(hid, report, USB_DIR_IN);
690 			usbhid_wait_io(hid);
691 		}
692 		mutex_unlock(&hiddev->existancelock);
693 
694 		return 0;
695 
696 	case HIDIOCSREPORT:
697 		if (copy_from_user(&rinfo, user_arg, sizeof(rinfo)))
698 			return -EFAULT;
699 
700 		if (rinfo.report_type == HID_REPORT_TYPE_INPUT)
701 			return -EINVAL;
702 
703 		if ((report = hiddev_lookup_report(hid, &rinfo)) == NULL)
704 			return -EINVAL;
705 
706 		mutex_lock(&hiddev->existancelock);
707 		if (hiddev->exist) {
708 			usbhid_submit_report(hid, report, USB_DIR_OUT);
709 			usbhid_wait_io(hid);
710 		}
711 		mutex_unlock(&hiddev->existancelock);
712 
713 		return 0;
714 
715 	case HIDIOCGREPORTINFO:
716 		if (copy_from_user(&rinfo, user_arg, sizeof(rinfo)))
717 			return -EFAULT;
718 
719 		if ((report = hiddev_lookup_report(hid, &rinfo)) == NULL)
720 			return -EINVAL;
721 
722 		rinfo.num_fields = report->maxfield;
723 
724 		if (copy_to_user(user_arg, &rinfo, sizeof(rinfo)))
725 			return -EFAULT;
726 
727 		return 0;
728 
729 	case HIDIOCGFIELDINFO:
730 		if (copy_from_user(&finfo, user_arg, sizeof(finfo)))
731 			return -EFAULT;
732 		rinfo.report_type = finfo.report_type;
733 		rinfo.report_id = finfo.report_id;
734 		if ((report = hiddev_lookup_report(hid, &rinfo)) == NULL)
735 			return -EINVAL;
736 
737 		if (finfo.field_index >= report->maxfield)
738 			return -EINVAL;
739 
740 		field = report->field[finfo.field_index];
741 		memset(&finfo, 0, sizeof(finfo));
742 		finfo.report_type = rinfo.report_type;
743 		finfo.report_id = rinfo.report_id;
744 		finfo.field_index = field->report_count - 1;
745 		finfo.maxusage = field->maxusage;
746 		finfo.flags = field->flags;
747 		finfo.physical = field->physical;
748 		finfo.logical = field->logical;
749 		finfo.application = field->application;
750 		finfo.logical_minimum = field->logical_minimum;
751 		finfo.logical_maximum = field->logical_maximum;
752 		finfo.physical_minimum = field->physical_minimum;
753 		finfo.physical_maximum = field->physical_maximum;
754 		finfo.unit_exponent = field->unit_exponent;
755 		finfo.unit = field->unit;
756 
757 		if (copy_to_user(user_arg, &finfo, sizeof(finfo)))
758 			return -EFAULT;
759 
760 		return 0;
761 
762 	case HIDIOCGUCODE:
763 		/* fall through */
764 	case HIDIOCGUSAGE:
765 	case HIDIOCSUSAGE:
766 	case HIDIOCGUSAGES:
767 	case HIDIOCSUSAGES:
768 	case HIDIOCGCOLLECTIONINDEX:
769 		mutex_lock(&hiddev->existancelock);
770 		if (hiddev->exist)
771 			r = hiddev_ioctl_usage(hiddev, cmd, user_arg);
772 		else
773 			r = -ENODEV;
774 		mutex_unlock(&hiddev->existancelock);
775 		return r;
776 
777 	case HIDIOCGCOLLECTIONINFO:
778 		if (copy_from_user(&cinfo, user_arg, sizeof(cinfo)))
779 			return -EFAULT;
780 
781 		if (cinfo.index >= hid->maxcollection)
782 			return -EINVAL;
783 
784 		cinfo.type = hid->collection[cinfo.index].type;
785 		cinfo.usage = hid->collection[cinfo.index].usage;
786 		cinfo.level = hid->collection[cinfo.index].level;
787 
788 		if (copy_to_user(user_arg, &cinfo, sizeof(cinfo)))
789 			return -EFAULT;
790 		return 0;
791 
792 	default:
793 
794 		if (_IOC_TYPE(cmd) != 'H' || _IOC_DIR(cmd) != _IOC_READ)
795 			return -EINVAL;
796 
797 		if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGNAME(0))) {
798 			int len;
799 			if (!hid->name)
800 				return 0;
801 			len = strlen(hid->name) + 1;
802 			if (len > _IOC_SIZE(cmd))
803 				 len = _IOC_SIZE(cmd);
804 			return copy_to_user(user_arg, hid->name, len) ?
805 				-EFAULT : len;
806 		}
807 
808 		if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGPHYS(0))) {
809 			int len;
810 			if (!hid->phys)
811 				return 0;
812 			len = strlen(hid->phys) + 1;
813 			if (len > _IOC_SIZE(cmd))
814 				len = _IOC_SIZE(cmd);
815 			return copy_to_user(user_arg, hid->phys, len) ?
816 				-EFAULT : len;
817 		}
818 	}
819 	return -EINVAL;
820 }
821 
822 #ifdef CONFIG_COMPAT
823 static long hiddev_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
824 {
825 	return hiddev_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
826 }
827 #endif
828 
829 static const struct file_operations hiddev_fops = {
830 	.owner =	THIS_MODULE,
831 	.read =		hiddev_read,
832 	.write =	hiddev_write,
833 	.poll =		hiddev_poll,
834 	.open =		hiddev_open,
835 	.release =	hiddev_release,
836 	.unlocked_ioctl =	hiddev_ioctl,
837 	.fasync =	hiddev_fasync,
838 #ifdef CONFIG_COMPAT
839 	.compat_ioctl	= hiddev_compat_ioctl,
840 #endif
841 };
842 
843 static struct usb_class_driver hiddev_class = {
844 	.name =		"hiddev%d",
845 	.fops =		&hiddev_fops,
846 	.minor_base =	HIDDEV_MINOR_BASE,
847 };
848 
849 /*
850  * This is where hid.c calls us to connect a hid device to the hiddev driver
851  */
852 int hiddev_connect(struct hid_device *hid, unsigned int force)
853 {
854 	struct hiddev *hiddev;
855 	struct usbhid_device *usbhid = hid->driver_data;
856 	int retval;
857 
858 	if (!force) {
859 		unsigned int i;
860 		for (i = 0; i < hid->maxcollection; i++)
861 			if (hid->collection[i].type ==
862 			    HID_COLLECTION_APPLICATION &&
863 			    !IS_INPUT_APPLICATION(hid->collection[i].usage))
864 				break;
865 
866 		if (i == hid->maxcollection)
867 			return -1;
868 	}
869 
870 	if (!(hiddev = kzalloc(sizeof(struct hiddev), GFP_KERNEL)))
871 		return -1;
872 
873 	init_waitqueue_head(&hiddev->wait);
874 	INIT_LIST_HEAD(&hiddev->list);
875 	spin_lock_init(&hiddev->list_lock);
876 	mutex_init(&hiddev->existancelock);
877 	hid->hiddev = hiddev;
878 	hiddev->hid = hid;
879 	hiddev->exist = 1;
880 
881 	retval = usb_register_dev(usbhid->intf, &hiddev_class);
882 	if (retval) {
883 		err_hid("Not able to get a minor for this device.");
884 		hid->hiddev = NULL;
885 		kfree(hiddev);
886 		return -1;
887 	} else {
888 		hid->minor = usbhid->intf->minor;
889 		hiddev_table[usbhid->intf->minor - HIDDEV_MINOR_BASE] = hiddev;
890 	}
891 
892 	return 0;
893 }
894 
895 /*
896  * This is where hid.c calls us to disconnect a hiddev device from the
897  * corresponding hid device (usually because the usb device has disconnected)
898  */
899 static struct usb_class_driver hiddev_class;
900 void hiddev_disconnect(struct hid_device *hid)
901 {
902 	struct hiddev *hiddev = hid->hiddev;
903 	struct usbhid_device *usbhid = hid->driver_data;
904 
905 	mutex_lock(&hiddev->existancelock);
906 	hiddev->exist = 0;
907 	mutex_unlock(&hiddev->existancelock);
908 
909 	hiddev_table[hiddev->hid->minor - HIDDEV_MINOR_BASE] = NULL;
910 	usb_deregister_dev(usbhid->intf, &hiddev_class);
911 
912 	if (hiddev->open) {
913 		usbhid_close(hiddev->hid);
914 		wake_up_interruptible(&hiddev->wait);
915 	} else {
916 		kfree(hiddev);
917 	}
918 }
919 
920 /* Currently this driver is a USB driver.  It's not a conventional one in
921  * the sense that it doesn't probe at the USB level.  Instead it waits to
922  * be connected by HID through the hiddev_connect / hiddev_disconnect
923  * routines.  The reason to register as a USB device is to gain part of the
924  * minor number space from the USB major.
925  *
926  * In theory, should the HID code be generalized to more than one physical
927  * medium (say, IEEE 1384), this driver will probably need to register its
928  * own major number, and in doing so, no longer need to register with USB.
929  * At that point the probe routine and hiddev_driver struct below will no
930  * longer be useful.
931  */
932 
933 
934 /* We never attach in this manner, and rely on HID to connect us.  This
935  * is why there is no disconnect routine defined in the usb_driver either.
936  */
937 static int hiddev_usbd_probe(struct usb_interface *intf,
938 			     const struct usb_device_id *hiddev_info)
939 {
940 	return -ENODEV;
941 }
942 
943 
944 static /* const */ struct usb_driver hiddev_driver = {
945 	.name =		"hiddev",
946 	.probe =	hiddev_usbd_probe,
947 };
948 
949 int __init hiddev_init(void)
950 {
951 	return usb_register(&hiddev_driver);
952 }
953 
954 void hiddev_exit(void)
955 {
956 	usb_deregister(&hiddev_driver);
957 }
958