xref: /openbmc/linux/drivers/hid/usbhid/hiddev.c (revision 93dc544c)
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 	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 };
67 
68 static struct hiddev *hiddev_table[HIDDEV_MINORS];
69 
70 /*
71  * Find a report, given the report's type and ID.  The ID can be specified
72  * indirectly by REPORT_ID_FIRST (which returns the first report of the given
73  * type) or by (REPORT_ID_NEXT | old_id), which returns the next report of the
74  * given type which follows old_id.
75  */
76 static struct hid_report *
77 hiddev_lookup_report(struct hid_device *hid, struct hiddev_report_info *rinfo)
78 {
79 	unsigned int flags = rinfo->report_id & ~HID_REPORT_ID_MASK;
80 	unsigned int rid = rinfo->report_id & HID_REPORT_ID_MASK;
81 	struct hid_report_enum *report_enum;
82 	struct hid_report *report;
83 	struct list_head *list;
84 
85 	if (rinfo->report_type < HID_REPORT_TYPE_MIN ||
86 	    rinfo->report_type > HID_REPORT_TYPE_MAX)
87 		return NULL;
88 
89 	report_enum = hid->report_enum +
90 		(rinfo->report_type - HID_REPORT_TYPE_MIN);
91 
92 	switch (flags) {
93 	case 0: /* Nothing to do -- report_id is already set correctly */
94 		break;
95 
96 	case HID_REPORT_ID_FIRST:
97 		if (list_empty(&report_enum->report_list))
98 			return NULL;
99 
100 		list = report_enum->report_list.next;
101 		report = list_entry(list, struct hid_report, list);
102 		rinfo->report_id = report->id;
103 		break;
104 
105 	case HID_REPORT_ID_NEXT:
106 		report = report_enum->report_id_hash[rid];
107 		if (!report)
108 			return NULL;
109 
110 		list = report->list.next;
111 		if (list == &report_enum->report_list)
112 			return NULL;
113 
114 		report = list_entry(list, struct hid_report, list);
115 		rinfo->report_id = report->id;
116 		break;
117 
118 	default:
119 		return NULL;
120 	}
121 
122 	return report_enum->report_id_hash[rinfo->report_id];
123 }
124 
125 /*
126  * Perform an exhaustive search of the report table for a usage, given its
127  * type and usage id.
128  */
129 static struct hid_field *
130 hiddev_lookup_usage(struct hid_device *hid, struct hiddev_usage_ref *uref)
131 {
132 	int i, j;
133 	struct hid_report *report;
134 	struct hid_report_enum *report_enum;
135 	struct hid_field *field;
136 
137 	if (uref->report_type < HID_REPORT_TYPE_MIN ||
138 	    uref->report_type > HID_REPORT_TYPE_MAX)
139 		return NULL;
140 
141 	report_enum = hid->report_enum +
142 		(uref->report_type - HID_REPORT_TYPE_MIN);
143 
144 	list_for_each_entry(report, &report_enum->report_list, list) {
145 		for (i = 0; i < report->maxfield; i++) {
146 			field = report->field[i];
147 			for (j = 0; j < field->maxusage; j++) {
148 				if (field->usage[j].hid == uref->usage_code) {
149 					uref->report_id = report->id;
150 					uref->field_index = i;
151 					uref->usage_index = j;
152 					return field;
153 				}
154 			}
155 		}
156 	}
157 
158 	return NULL;
159 }
160 
161 static void hiddev_send_event(struct hid_device *hid,
162 			      struct hiddev_usage_ref *uref)
163 {
164 	struct hiddev *hiddev = hid->hiddev;
165 	struct hiddev_list *list;
166 	unsigned long flags;
167 
168 	spin_lock_irqsave(&hiddev->list_lock, flags);
169 	list_for_each_entry(list, &hiddev->list, node) {
170 		if (uref->field_index != HID_FIELD_INDEX_NONE ||
171 		    (list->flags & HIDDEV_FLAG_REPORT) != 0) {
172 			list->buffer[list->head] = *uref;
173 			list->head = (list->head + 1) &
174 				(HIDDEV_BUFFER_SIZE - 1);
175 			kill_fasync(&list->fasync, SIGIO, POLL_IN);
176 		}
177 	}
178 	spin_unlock_irqrestore(&hiddev->list_lock, flags);
179 
180 	wake_up_interruptible(&hiddev->wait);
181 }
182 
183 /*
184  * This is where hid.c calls into hiddev to pass an event that occurred over
185  * the interrupt pipe
186  */
187 void hiddev_hid_event(struct hid_device *hid, struct hid_field *field,
188 		      struct hid_usage *usage, __s32 value)
189 {
190 	unsigned type = field->report_type;
191 	struct hiddev_usage_ref uref;
192 
193 	uref.report_type =
194 	  (type == HID_INPUT_REPORT) ? HID_REPORT_TYPE_INPUT :
195 	  ((type == HID_OUTPUT_REPORT) ? HID_REPORT_TYPE_OUTPUT :
196 	   ((type == HID_FEATURE_REPORT) ? HID_REPORT_TYPE_FEATURE : 0));
197 	uref.report_id = field->report->id;
198 	uref.field_index = field->index;
199 	uref.usage_index = (usage - field->usage);
200 	uref.usage_code = usage->hid;
201 	uref.value = value;
202 
203 	hiddev_send_event(hid, &uref);
204 }
205 EXPORT_SYMBOL_GPL(hiddev_hid_event);
206 
207 void hiddev_report_event(struct hid_device *hid, struct hid_report *report)
208 {
209 	unsigned type = report->type;
210 	struct hiddev_usage_ref uref;
211 
212 	memset(&uref, 0, sizeof(uref));
213 	uref.report_type =
214 	  (type == HID_INPUT_REPORT) ? HID_REPORT_TYPE_INPUT :
215 	  ((type == HID_OUTPUT_REPORT) ? HID_REPORT_TYPE_OUTPUT :
216 	   ((type == HID_FEATURE_REPORT) ? HID_REPORT_TYPE_FEATURE : 0));
217 	uref.report_id = report->id;
218 	uref.field_index = HID_FIELD_INDEX_NONE;
219 
220 	hiddev_send_event(hid, &uref);
221 }
222 
223 /*
224  * fasync file op
225  */
226 static int hiddev_fasync(int fd, struct file *file, int on)
227 {
228 	int retval;
229 	struct hiddev_list *list = file->private_data;
230 
231 	retval = fasync_helper(fd, file, on, &list->fasync);
232 
233 	return retval < 0 ? retval : 0;
234 }
235 
236 
237 /*
238  * release file op
239  */
240 static int hiddev_release(struct inode * inode, struct file * file)
241 {
242 	struct hiddev_list *list = file->private_data;
243 	unsigned long flags;
244 
245 	hiddev_fasync(-1, file, 0);
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 	unsigned long flags;
270 
271 	int i = iminor(inode) - HIDDEV_MINOR_BASE;
272 
273 	if (i >= HIDDEV_MINORS || !hiddev_table[i])
274 		return -ENODEV;
275 
276 	if (!(list = kzalloc(sizeof(struct hiddev_list), GFP_KERNEL)))
277 		return -ENOMEM;
278 
279 	list->hiddev = hiddev_table[i];
280 
281 	spin_lock_irqsave(&list->hiddev->list_lock, flags);
282 	list_add_tail(&list->node, &hiddev_table[i]->list);
283 	spin_unlock_irqrestore(&list->hiddev->list_lock, flags);
284 
285 	file->private_data = list;
286 
287 	if (!list->hiddev->open++)
288 		if (list->hiddev->exist)
289 			usbhid_open(hiddev_table[i]->hid);
290 
291 	return 0;
292 }
293 
294 /*
295  * "write" file op
296  */
297 static ssize_t hiddev_write(struct file * file, const char __user * buffer, size_t count, loff_t *ppos)
298 {
299 	return -EINVAL;
300 }
301 
302 /*
303  * "read" file op
304  */
305 static ssize_t hiddev_read(struct file * file, char __user * buffer, size_t count, loff_t *ppos)
306 {
307 	DECLARE_WAITQUEUE(wait, current);
308 	struct hiddev_list *list = file->private_data;
309 	int event_size;
310 	int retval = 0;
311 
312 	event_size = ((list->flags & HIDDEV_FLAG_UREF) != 0) ?
313 		sizeof(struct hiddev_usage_ref) : sizeof(struct hiddev_event);
314 
315 	if (count < event_size)
316 		return 0;
317 
318 	while (retval == 0) {
319 		if (list->head == list->tail) {
320 			add_wait_queue(&list->hiddev->wait, &wait);
321 			set_current_state(TASK_INTERRUPTIBLE);
322 
323 			while (list->head == list->tail) {
324 				if (file->f_flags & O_NONBLOCK) {
325 					retval = -EAGAIN;
326 					break;
327 				}
328 				if (signal_pending(current)) {
329 					retval = -ERESTARTSYS;
330 					break;
331 				}
332 				if (!list->hiddev->exist) {
333 					retval = -EIO;
334 					break;
335 				}
336 
337 				schedule();
338 				set_current_state(TASK_INTERRUPTIBLE);
339 			}
340 
341 			set_current_state(TASK_RUNNING);
342 			remove_wait_queue(&list->hiddev->wait, &wait);
343 		}
344 
345 		if (retval)
346 			return retval;
347 
348 
349 		while (list->head != list->tail &&
350 		       retval + event_size <= count) {
351 			if ((list->flags & HIDDEV_FLAG_UREF) == 0) {
352 				if (list->buffer[list->tail].field_index !=
353 				    HID_FIELD_INDEX_NONE) {
354 					struct hiddev_event event;
355 					event.hid = list->buffer[list->tail].usage_code;
356 					event.value = list->buffer[list->tail].value;
357 					if (copy_to_user(buffer + retval, &event, sizeof(struct hiddev_event)))
358 						return -EFAULT;
359 					retval += sizeof(struct hiddev_event);
360 				}
361 			} else {
362 				if (list->buffer[list->tail].field_index != HID_FIELD_INDEX_NONE ||
363 				    (list->flags & HIDDEV_FLAG_REPORT) != 0) {
364 					if (copy_to_user(buffer + retval, list->buffer + list->tail, sizeof(struct hiddev_usage_ref)))
365 						return -EFAULT;
366 					retval += sizeof(struct hiddev_usage_ref);
367 				}
368 			}
369 			list->tail = (list->tail + 1) & (HIDDEV_BUFFER_SIZE - 1);
370 		}
371 
372 	}
373 
374 	return retval;
375 }
376 
377 /*
378  * "poll" file op
379  * No kernel lock - fine
380  */
381 static unsigned int hiddev_poll(struct file *file, poll_table *wait)
382 {
383 	struct hiddev_list *list = file->private_data;
384 
385 	poll_wait(file, &list->hiddev->wait, wait);
386 	if (list->head != list->tail)
387 		return POLLIN | POLLRDNORM;
388 	if (!list->hiddev->exist)
389 		return POLLERR | POLLHUP;
390 	return 0;
391 }
392 
393 /*
394  * "ioctl" file op
395  */
396 static noinline int hiddev_ioctl_usage(struct hiddev *hiddev, unsigned int cmd, void __user *user_arg)
397 {
398 	struct hid_device *hid = hiddev->hid;
399 	struct hiddev_report_info rinfo;
400 	struct hiddev_usage_ref_multi *uref_multi = NULL;
401 	struct hiddev_usage_ref *uref;
402 	struct hid_report *report;
403 	struct hid_field *field;
404 	int i;
405 
406 	uref_multi = kmalloc(sizeof(struct hiddev_usage_ref_multi), GFP_KERNEL);
407 	if (!uref_multi)
408 		return -ENOMEM;
409 	lock_kernel();
410 	uref = &uref_multi->uref;
411 	if (cmd == HIDIOCGUSAGES || cmd == HIDIOCSUSAGES) {
412 		if (copy_from_user(uref_multi, user_arg,
413 				   sizeof(*uref_multi)))
414 			goto fault;
415 	} else {
416 		if (copy_from_user(uref, user_arg, sizeof(*uref)))
417 			goto fault;
418 	}
419 
420 	switch (cmd) {
421 	case HIDIOCGUCODE:
422 		rinfo.report_type = uref->report_type;
423 		rinfo.report_id = uref->report_id;
424 		if ((report = hiddev_lookup_report(hid, &rinfo)) == NULL)
425 			goto inval;
426 
427 		if (uref->field_index >= report->maxfield)
428 			goto inval;
429 
430 		field = report->field[uref->field_index];
431 		if (uref->usage_index >= field->maxusage)
432 			goto inval;
433 
434 		uref->usage_code = field->usage[uref->usage_index].hid;
435 
436 		if (copy_to_user(user_arg, uref, sizeof(*uref)))
437 			goto fault;
438 
439 		kfree(uref_multi);
440 		return 0;
441 
442 	default:
443 		if (cmd != HIDIOCGUSAGE &&
444 		    cmd != HIDIOCGUSAGES &&
445 		    uref->report_type == HID_REPORT_TYPE_INPUT)
446 			goto inval;
447 
448 		if (uref->report_id == HID_REPORT_ID_UNKNOWN) {
449 			field = hiddev_lookup_usage(hid, uref);
450 			if (field == NULL)
451 				goto inval;
452 		} else {
453 			rinfo.report_type = uref->report_type;
454 			rinfo.report_id = uref->report_id;
455 			if ((report = hiddev_lookup_report(hid, &rinfo)) == NULL)
456 				goto inval;
457 
458 			if (uref->field_index >= report->maxfield)
459 				goto inval;
460 
461 			field = report->field[uref->field_index];
462 
463 			if (cmd == HIDIOCGCOLLECTIONINDEX) {
464 				if (uref->usage_index >= field->maxusage)
465 					goto inval;
466 			} else if (uref->usage_index >= field->report_count)
467 				goto inval;
468 
469 			else if ((cmd == HIDIOCGUSAGES || cmd == HIDIOCSUSAGES) &&
470 				 (uref_multi->num_values > HID_MAX_MULTI_USAGES ||
471 				  uref->usage_index + uref_multi->num_values > field->report_count))
472 				goto inval;
473 			}
474 
475 		switch (cmd) {
476 		case HIDIOCGUSAGE:
477 			uref->value = field->value[uref->usage_index];
478 			if (copy_to_user(user_arg, uref, sizeof(*uref)))
479 				goto fault;
480 			goto goodreturn;
481 
482 		case HIDIOCSUSAGE:
483 			field->value[uref->usage_index] = uref->value;
484 			goto goodreturn;
485 
486 		case HIDIOCGCOLLECTIONINDEX:
487 			kfree(uref_multi);
488 			return field->usage[uref->usage_index].collection_index;
489 		case HIDIOCGUSAGES:
490 			for (i = 0; i < uref_multi->num_values; i++)
491 				uref_multi->values[i] =
492 				    field->value[uref->usage_index + i];
493 			if (copy_to_user(user_arg, uref_multi,
494 					 sizeof(*uref_multi)))
495 				goto fault;
496 			goto goodreturn;
497 		case HIDIOCSUSAGES:
498 			for (i = 0; i < uref_multi->num_values; i++)
499 				field->value[uref->usage_index + i] =
500 				    uref_multi->values[i];
501 			goto goodreturn;
502 		}
503 
504 goodreturn:
505 		unlock_kernel();
506 		kfree(uref_multi);
507 		return 0;
508 fault:
509 		unlock_kernel();
510 		kfree(uref_multi);
511 		return -EFAULT;
512 inval:
513 		unlock_kernel();
514 		kfree(uref_multi);
515 		return -EINVAL;
516 	}
517 }
518 
519 static noinline int hiddev_ioctl_string(struct hiddev *hiddev, unsigned int cmd, void __user *user_arg)
520 {
521 	struct hid_device *hid = hiddev->hid;
522 	struct usb_device *dev = hid_to_usb_dev(hid);
523 	int idx, len;
524 	char *buf;
525 
526 	if (get_user(idx, (int __user *)user_arg))
527 		return -EFAULT;
528 
529 	if ((buf = kmalloc(HID_STRING_SIZE, GFP_KERNEL)) == NULL)
530 		return -ENOMEM;
531 
532 	if ((len = usb_string(dev, idx, buf, HID_STRING_SIZE-1)) < 0) {
533 		kfree(buf);
534 		return -EINVAL;
535 	}
536 
537 	if (copy_to_user(user_arg+sizeof(int), buf, len+1)) {
538 		kfree(buf);
539 		return -EFAULT;
540 	}
541 
542 	kfree(buf);
543 
544 	return len;
545 }
546 
547 static long hiddev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
548 {
549 	struct hiddev_list *list = file->private_data;
550 	struct hiddev *hiddev = list->hiddev;
551 	struct hid_device *hid = hiddev->hid;
552 	struct usb_device *dev = hid_to_usb_dev(hid);
553 	struct hiddev_collection_info cinfo;
554 	struct hiddev_report_info rinfo;
555 	struct hiddev_field_info finfo;
556 	struct hiddev_devinfo dinfo;
557 	struct hid_report *report;
558 	struct hid_field *field;
559 	struct usbhid_device *usbhid = hid->driver_data;
560 	void __user *user_arg = (void __user *)arg;
561 	int i;
562 
563 	/* Called without BKL by compat methods so no BKL taken */
564 
565 	/* FIXME: Who or what stop this racing with a disconnect ?? */
566 	if (!hiddev->exist)
567 		return -EIO;
568 
569 	switch (cmd) {
570 
571 	case HIDIOCGVERSION:
572 		return put_user(HID_VERSION, (int __user *)arg);
573 
574 	case HIDIOCAPPLICATION:
575 		if (arg < 0 || arg >= hid->maxapplication)
576 			return -EINVAL;
577 
578 		for (i = 0; i < hid->maxcollection; i++)
579 			if (hid->collection[i].type ==
580 			    HID_COLLECTION_APPLICATION && arg-- == 0)
581 				break;
582 
583 		if (i == hid->maxcollection)
584 			return -EINVAL;
585 
586 		return hid->collection[i].usage;
587 
588 	case HIDIOCGDEVINFO:
589 		dinfo.bustype = BUS_USB;
590 		dinfo.busnum = dev->bus->busnum;
591 		dinfo.devnum = dev->devnum;
592 		dinfo.ifnum = usbhid->ifnum;
593 		dinfo.vendor = le16_to_cpu(dev->descriptor.idVendor);
594 		dinfo.product = le16_to_cpu(dev->descriptor.idProduct);
595 		dinfo.version = le16_to_cpu(dev->descriptor.bcdDevice);
596 		dinfo.num_applications = hid->maxapplication;
597 		if (copy_to_user(user_arg, &dinfo, sizeof(dinfo)))
598 			return -EFAULT;
599 
600 		return 0;
601 
602 	case HIDIOCGFLAG:
603 		if (put_user(list->flags, (int __user *)arg))
604 			return -EFAULT;
605 
606 		return 0;
607 
608 	case HIDIOCSFLAG:
609 		{
610 			int newflags;
611 			if (get_user(newflags, (int __user *)arg))
612 				return -EFAULT;
613 
614 			if ((newflags & ~HIDDEV_FLAGS) != 0 ||
615 			    ((newflags & HIDDEV_FLAG_REPORT) != 0 &&
616 			     (newflags & HIDDEV_FLAG_UREF) == 0))
617 				return -EINVAL;
618 
619 			list->flags = newflags;
620 
621 			return 0;
622 		}
623 
624 	case HIDIOCGSTRING:
625 		return hiddev_ioctl_string(hiddev, cmd, user_arg);
626 
627 	case HIDIOCINITREPORT:
628 		usbhid_init_reports(hid);
629 
630 		return 0;
631 
632 	case HIDIOCGREPORT:
633 		if (copy_from_user(&rinfo, user_arg, sizeof(rinfo)))
634 			return -EFAULT;
635 
636 		if (rinfo.report_type == HID_REPORT_TYPE_OUTPUT)
637 			return -EINVAL;
638 
639 		if ((report = hiddev_lookup_report(hid, &rinfo)) == NULL)
640 			return -EINVAL;
641 
642 		usbhid_submit_report(hid, report, USB_DIR_IN);
643 		usbhid_wait_io(hid);
644 
645 		return 0;
646 
647 	case HIDIOCSREPORT:
648 		if (copy_from_user(&rinfo, user_arg, sizeof(rinfo)))
649 			return -EFAULT;
650 
651 		if (rinfo.report_type == HID_REPORT_TYPE_INPUT)
652 			return -EINVAL;
653 
654 		if ((report = hiddev_lookup_report(hid, &rinfo)) == NULL)
655 			return -EINVAL;
656 
657 		usbhid_submit_report(hid, report, USB_DIR_OUT);
658 		usbhid_wait_io(hid);
659 
660 		return 0;
661 
662 	case HIDIOCGREPORTINFO:
663 		if (copy_from_user(&rinfo, user_arg, sizeof(rinfo)))
664 			return -EFAULT;
665 
666 		if ((report = hiddev_lookup_report(hid, &rinfo)) == NULL)
667 			return -EINVAL;
668 
669 		rinfo.num_fields = report->maxfield;
670 
671 		if (copy_to_user(user_arg, &rinfo, sizeof(rinfo)))
672 			return -EFAULT;
673 
674 		return 0;
675 
676 	case HIDIOCGFIELDINFO:
677 		if (copy_from_user(&finfo, user_arg, sizeof(finfo)))
678 			return -EFAULT;
679 		rinfo.report_type = finfo.report_type;
680 		rinfo.report_id = finfo.report_id;
681 		if ((report = hiddev_lookup_report(hid, &rinfo)) == NULL)
682 			return -EINVAL;
683 
684 		if (finfo.field_index >= report->maxfield)
685 			return -EINVAL;
686 
687 		field = report->field[finfo.field_index];
688 		memset(&finfo, 0, sizeof(finfo));
689 		finfo.report_type = rinfo.report_type;
690 		finfo.report_id = rinfo.report_id;
691 		finfo.field_index = field->report_count - 1;
692 		finfo.maxusage = field->maxusage;
693 		finfo.flags = field->flags;
694 		finfo.physical = field->physical;
695 		finfo.logical = field->logical;
696 		finfo.application = field->application;
697 		finfo.logical_minimum = field->logical_minimum;
698 		finfo.logical_maximum = field->logical_maximum;
699 		finfo.physical_minimum = field->physical_minimum;
700 		finfo.physical_maximum = field->physical_maximum;
701 		finfo.unit_exponent = field->unit_exponent;
702 		finfo.unit = field->unit;
703 
704 		if (copy_to_user(user_arg, &finfo, sizeof(finfo)))
705 			return -EFAULT;
706 
707 		return 0;
708 
709 	case HIDIOCGUCODE:
710 		/* fall through */
711 	case HIDIOCGUSAGE:
712 	case HIDIOCSUSAGE:
713 	case HIDIOCGUSAGES:
714 	case HIDIOCSUSAGES:
715 	case HIDIOCGCOLLECTIONINDEX:
716 		return hiddev_ioctl_usage(hiddev, cmd, user_arg);
717 
718 	case HIDIOCGCOLLECTIONINFO:
719 		if (copy_from_user(&cinfo, user_arg, sizeof(cinfo)))
720 			return -EFAULT;
721 
722 		if (cinfo.index >= hid->maxcollection)
723 			return -EINVAL;
724 
725 		cinfo.type = hid->collection[cinfo.index].type;
726 		cinfo.usage = hid->collection[cinfo.index].usage;
727 		cinfo.level = hid->collection[cinfo.index].level;
728 
729 		if (copy_to_user(user_arg, &cinfo, sizeof(cinfo)))
730 			return -EFAULT;
731 		return 0;
732 
733 	default:
734 
735 		if (_IOC_TYPE(cmd) != 'H' || _IOC_DIR(cmd) != _IOC_READ)
736 			return -EINVAL;
737 
738 		if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGNAME(0))) {
739 			int len;
740 			if (!hid->name)
741 				return 0;
742 			len = strlen(hid->name) + 1;
743 			if (len > _IOC_SIZE(cmd))
744 				 len = _IOC_SIZE(cmd);
745 			return copy_to_user(user_arg, hid->name, len) ?
746 				-EFAULT : len;
747 		}
748 
749 		if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGPHYS(0))) {
750 			int len;
751 			if (!hid->phys)
752 				return 0;
753 			len = strlen(hid->phys) + 1;
754 			if (len > _IOC_SIZE(cmd))
755 				len = _IOC_SIZE(cmd);
756 			return copy_to_user(user_arg, hid->phys, len) ?
757 				-EFAULT : len;
758 		}
759 	}
760 	return -EINVAL;
761 }
762 
763 #ifdef CONFIG_COMPAT
764 static long hiddev_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
765 {
766 	return hiddev_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
767 }
768 #endif
769 
770 static const struct file_operations hiddev_fops = {
771 	.owner =	THIS_MODULE,
772 	.read =		hiddev_read,
773 	.write =	hiddev_write,
774 	.poll =		hiddev_poll,
775 	.open =		hiddev_open,
776 	.release =	hiddev_release,
777 	.unlocked_ioctl =	hiddev_ioctl,
778 	.fasync =	hiddev_fasync,
779 #ifdef CONFIG_COMPAT
780 	.compat_ioctl	= hiddev_compat_ioctl,
781 #endif
782 };
783 
784 static struct usb_class_driver hiddev_class = {
785 	.name =		"hiddev%d",
786 	.fops =		&hiddev_fops,
787 	.minor_base =	HIDDEV_MINOR_BASE,
788 };
789 
790 /*
791  * This is where hid.c calls us to connect a hid device to the hiddev driver
792  */
793 int hiddev_connect(struct hid_device *hid)
794 {
795 	struct hiddev *hiddev;
796 	struct usbhid_device *usbhid = hid->driver_data;
797 	int i;
798 	int retval;
799 
800 	for (i = 0; i < hid->maxcollection; i++)
801 		if (hid->collection[i].type ==
802 		    HID_COLLECTION_APPLICATION &&
803 		    !IS_INPUT_APPLICATION(hid->collection[i].usage))
804 			break;
805 
806 	if (i == hid->maxcollection && (hid->quirks & HID_QUIRK_HIDDEV) == 0)
807 		return -1;
808 
809 	if (!(hiddev = kzalloc(sizeof(struct hiddev), GFP_KERNEL)))
810 		return -1;
811 
812 	retval = usb_register_dev(usbhid->intf, &hiddev_class);
813 	if (retval) {
814 		err_hid("Not able to get a minor for this device.");
815 		kfree(hiddev);
816 		return -1;
817 	}
818 
819 	init_waitqueue_head(&hiddev->wait);
820 	INIT_LIST_HEAD(&hiddev->list);
821 	spin_lock_init(&hiddev->list_lock);
822 	hiddev->hid = hid;
823 	hiddev->exist = 1;
824 
825 	hid->minor = usbhid->intf->minor;
826 	hid->hiddev = hiddev;
827 
828 	hiddev_table[usbhid->intf->minor - HIDDEV_MINOR_BASE] = hiddev;
829 
830 	return 0;
831 }
832 
833 /*
834  * This is where hid.c calls us to disconnect a hiddev device from the
835  * corresponding hid device (usually because the usb device has disconnected)
836  */
837 static struct usb_class_driver hiddev_class;
838 void hiddev_disconnect(struct hid_device *hid)
839 {
840 	struct hiddev *hiddev = hid->hiddev;
841 	struct usbhid_device *usbhid = hid->driver_data;
842 
843 	hiddev->exist = 0;
844 
845 	hiddev_table[hiddev->hid->minor - HIDDEV_MINOR_BASE] = NULL;
846 	usb_deregister_dev(usbhid->intf, &hiddev_class);
847 
848 	if (hiddev->open) {
849 		usbhid_close(hiddev->hid);
850 		wake_up_interruptible(&hiddev->wait);
851 	} else {
852 		kfree(hiddev);
853 	}
854 }
855 
856 /* Currently this driver is a USB driver.  It's not a conventional one in
857  * the sense that it doesn't probe at the USB level.  Instead it waits to
858  * be connected by HID through the hiddev_connect / hiddev_disconnect
859  * routines.  The reason to register as a USB device is to gain part of the
860  * minor number space from the USB major.
861  *
862  * In theory, should the HID code be generalized to more than one physical
863  * medium (say, IEEE 1384), this driver will probably need to register its
864  * own major number, and in doing so, no longer need to register with USB.
865  * At that point the probe routine and hiddev_driver struct below will no
866  * longer be useful.
867  */
868 
869 
870 /* We never attach in this manner, and rely on HID to connect us.  This
871  * is why there is no disconnect routine defined in the usb_driver either.
872  */
873 static int hiddev_usbd_probe(struct usb_interface *intf,
874 			     const struct usb_device_id *hiddev_info)
875 {
876 	return -ENODEV;
877 }
878 
879 
880 static /* const */ struct usb_driver hiddev_driver = {
881 	.name =		"hiddev",
882 	.probe =	hiddev_usbd_probe,
883 };
884 
885 int __init hiddev_init(void)
886 {
887 	return usb_register(&hiddev_driver);
888 }
889 
890 void hiddev_exit(void)
891 {
892 	usb_deregister(&hiddev_driver);
893 }
894