xref: /openbmc/linux/drivers/hid/usbhid/hiddev.c (revision e8e0929d)
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	2048
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 			i = field->usage[uref->usage_index].collection_index;
531 			unlock_kernel();
532 			kfree(uref_multi);
533 			return i;
534 		case HIDIOCGUSAGES:
535 			for (i = 0; i < uref_multi->num_values; i++)
536 				uref_multi->values[i] =
537 				    field->value[uref->usage_index + i];
538 			if (copy_to_user(user_arg, uref_multi,
539 					 sizeof(*uref_multi)))
540 				goto fault;
541 			goto goodreturn;
542 		case HIDIOCSUSAGES:
543 			for (i = 0; i < uref_multi->num_values; i++)
544 				field->value[uref->usage_index + i] =
545 				    uref_multi->values[i];
546 			goto goodreturn;
547 		}
548 
549 goodreturn:
550 		unlock_kernel();
551 		kfree(uref_multi);
552 		return 0;
553 fault:
554 		unlock_kernel();
555 		kfree(uref_multi);
556 		return -EFAULT;
557 inval:
558 		unlock_kernel();
559 		kfree(uref_multi);
560 		return -EINVAL;
561 	}
562 }
563 
564 static noinline int hiddev_ioctl_string(struct hiddev *hiddev, unsigned int cmd, void __user *user_arg)
565 {
566 	struct hid_device *hid = hiddev->hid;
567 	struct usb_device *dev = hid_to_usb_dev(hid);
568 	int idx, len;
569 	char *buf;
570 
571 	if (get_user(idx, (int __user *)user_arg))
572 		return -EFAULT;
573 
574 	if ((buf = kmalloc(HID_STRING_SIZE, GFP_KERNEL)) == NULL)
575 		return -ENOMEM;
576 
577 	if ((len = usb_string(dev, idx, buf, HID_STRING_SIZE-1)) < 0) {
578 		kfree(buf);
579 		return -EINVAL;
580 	}
581 
582 	if (copy_to_user(user_arg+sizeof(int), buf, len+1)) {
583 		kfree(buf);
584 		return -EFAULT;
585 	}
586 
587 	kfree(buf);
588 
589 	return len;
590 }
591 
592 static long hiddev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
593 {
594 	struct hiddev_list *list = file->private_data;
595 	struct hiddev *hiddev = list->hiddev;
596 	struct hid_device *hid = hiddev->hid;
597 	struct usb_device *dev = hid_to_usb_dev(hid);
598 	struct hiddev_collection_info cinfo;
599 	struct hiddev_report_info rinfo;
600 	struct hiddev_field_info finfo;
601 	struct hiddev_devinfo dinfo;
602 	struct hid_report *report;
603 	struct hid_field *field;
604 	struct usbhid_device *usbhid = hid->driver_data;
605 	void __user *user_arg = (void __user *)arg;
606 	int i, r;
607 
608 	/* Called without BKL by compat methods so no BKL taken */
609 
610 	/* FIXME: Who or what stop this racing with a disconnect ?? */
611 	if (!hiddev->exist)
612 		return -EIO;
613 
614 	switch (cmd) {
615 
616 	case HIDIOCGVERSION:
617 		return put_user(HID_VERSION, (int __user *)arg);
618 
619 	case HIDIOCAPPLICATION:
620 		if (arg < 0 || arg >= hid->maxapplication)
621 			return -EINVAL;
622 
623 		for (i = 0; i < hid->maxcollection; i++)
624 			if (hid->collection[i].type ==
625 			    HID_COLLECTION_APPLICATION && arg-- == 0)
626 				break;
627 
628 		if (i == hid->maxcollection)
629 			return -EINVAL;
630 
631 		return hid->collection[i].usage;
632 
633 	case HIDIOCGDEVINFO:
634 		dinfo.bustype = BUS_USB;
635 		dinfo.busnum = dev->bus->busnum;
636 		dinfo.devnum = dev->devnum;
637 		dinfo.ifnum = usbhid->ifnum;
638 		dinfo.vendor = le16_to_cpu(dev->descriptor.idVendor);
639 		dinfo.product = le16_to_cpu(dev->descriptor.idProduct);
640 		dinfo.version = le16_to_cpu(dev->descriptor.bcdDevice);
641 		dinfo.num_applications = hid->maxapplication;
642 		if (copy_to_user(user_arg, &dinfo, sizeof(dinfo)))
643 			return -EFAULT;
644 
645 		return 0;
646 
647 	case HIDIOCGFLAG:
648 		if (put_user(list->flags, (int __user *)arg))
649 			return -EFAULT;
650 
651 		return 0;
652 
653 	case HIDIOCSFLAG:
654 		{
655 			int newflags;
656 			if (get_user(newflags, (int __user *)arg))
657 				return -EFAULT;
658 
659 			if ((newflags & ~HIDDEV_FLAGS) != 0 ||
660 			    ((newflags & HIDDEV_FLAG_REPORT) != 0 &&
661 			     (newflags & HIDDEV_FLAG_UREF) == 0))
662 				return -EINVAL;
663 
664 			list->flags = newflags;
665 
666 			return 0;
667 		}
668 
669 	case HIDIOCGSTRING:
670 		mutex_lock(&hiddev->existancelock);
671 		if (hiddev->exist)
672 			r = hiddev_ioctl_string(hiddev, cmd, user_arg);
673 		else
674 			r = -ENODEV;
675 		mutex_unlock(&hiddev->existancelock);
676 		return r;
677 
678 	case HIDIOCINITREPORT:
679 		mutex_lock(&hiddev->existancelock);
680 		if (!hiddev->exist) {
681 			mutex_unlock(&hiddev->existancelock);
682 			return -ENODEV;
683 		}
684 		usbhid_init_reports(hid);
685 		mutex_unlock(&hiddev->existancelock);
686 
687 		return 0;
688 
689 	case HIDIOCGREPORT:
690 		if (copy_from_user(&rinfo, user_arg, sizeof(rinfo)))
691 			return -EFAULT;
692 
693 		if (rinfo.report_type == HID_REPORT_TYPE_OUTPUT)
694 			return -EINVAL;
695 
696 		if ((report = hiddev_lookup_report(hid, &rinfo)) == NULL)
697 			return -EINVAL;
698 
699 		mutex_lock(&hiddev->existancelock);
700 		if (hiddev->exist) {
701 			usbhid_submit_report(hid, report, USB_DIR_IN);
702 			usbhid_wait_io(hid);
703 		}
704 		mutex_unlock(&hiddev->existancelock);
705 
706 		return 0;
707 
708 	case HIDIOCSREPORT:
709 		if (copy_from_user(&rinfo, user_arg, sizeof(rinfo)))
710 			return -EFAULT;
711 
712 		if (rinfo.report_type == HID_REPORT_TYPE_INPUT)
713 			return -EINVAL;
714 
715 		if ((report = hiddev_lookup_report(hid, &rinfo)) == NULL)
716 			return -EINVAL;
717 
718 		mutex_lock(&hiddev->existancelock);
719 		if (hiddev->exist) {
720 			usbhid_submit_report(hid, report, USB_DIR_OUT);
721 			usbhid_wait_io(hid);
722 		}
723 		mutex_unlock(&hiddev->existancelock);
724 
725 		return 0;
726 
727 	case HIDIOCGREPORTINFO:
728 		if (copy_from_user(&rinfo, user_arg, sizeof(rinfo)))
729 			return -EFAULT;
730 
731 		if ((report = hiddev_lookup_report(hid, &rinfo)) == NULL)
732 			return -EINVAL;
733 
734 		rinfo.num_fields = report->maxfield;
735 
736 		if (copy_to_user(user_arg, &rinfo, sizeof(rinfo)))
737 			return -EFAULT;
738 
739 		return 0;
740 
741 	case HIDIOCGFIELDINFO:
742 		if (copy_from_user(&finfo, user_arg, sizeof(finfo)))
743 			return -EFAULT;
744 		rinfo.report_type = finfo.report_type;
745 		rinfo.report_id = finfo.report_id;
746 		if ((report = hiddev_lookup_report(hid, &rinfo)) == NULL)
747 			return -EINVAL;
748 
749 		if (finfo.field_index >= report->maxfield)
750 			return -EINVAL;
751 
752 		field = report->field[finfo.field_index];
753 		memset(&finfo, 0, sizeof(finfo));
754 		finfo.report_type = rinfo.report_type;
755 		finfo.report_id = rinfo.report_id;
756 		finfo.field_index = field->report_count - 1;
757 		finfo.maxusage = field->maxusage;
758 		finfo.flags = field->flags;
759 		finfo.physical = field->physical;
760 		finfo.logical = field->logical;
761 		finfo.application = field->application;
762 		finfo.logical_minimum = field->logical_minimum;
763 		finfo.logical_maximum = field->logical_maximum;
764 		finfo.physical_minimum = field->physical_minimum;
765 		finfo.physical_maximum = field->physical_maximum;
766 		finfo.unit_exponent = field->unit_exponent;
767 		finfo.unit = field->unit;
768 
769 		if (copy_to_user(user_arg, &finfo, sizeof(finfo)))
770 			return -EFAULT;
771 
772 		return 0;
773 
774 	case HIDIOCGUCODE:
775 		/* fall through */
776 	case HIDIOCGUSAGE:
777 	case HIDIOCSUSAGE:
778 	case HIDIOCGUSAGES:
779 	case HIDIOCSUSAGES:
780 	case HIDIOCGCOLLECTIONINDEX:
781 		mutex_lock(&hiddev->existancelock);
782 		if (hiddev->exist)
783 			r = hiddev_ioctl_usage(hiddev, cmd, user_arg);
784 		else
785 			r = -ENODEV;
786 		mutex_unlock(&hiddev->existancelock);
787 		return r;
788 
789 	case HIDIOCGCOLLECTIONINFO:
790 		if (copy_from_user(&cinfo, user_arg, sizeof(cinfo)))
791 			return -EFAULT;
792 
793 		if (cinfo.index >= hid->maxcollection)
794 			return -EINVAL;
795 
796 		cinfo.type = hid->collection[cinfo.index].type;
797 		cinfo.usage = hid->collection[cinfo.index].usage;
798 		cinfo.level = hid->collection[cinfo.index].level;
799 
800 		if (copy_to_user(user_arg, &cinfo, sizeof(cinfo)))
801 			return -EFAULT;
802 		return 0;
803 
804 	default:
805 
806 		if (_IOC_TYPE(cmd) != 'H' || _IOC_DIR(cmd) != _IOC_READ)
807 			return -EINVAL;
808 
809 		if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGNAME(0))) {
810 			int len;
811 			if (!hid->name)
812 				return 0;
813 			len = strlen(hid->name) + 1;
814 			if (len > _IOC_SIZE(cmd))
815 				 len = _IOC_SIZE(cmd);
816 			return copy_to_user(user_arg, hid->name, len) ?
817 				-EFAULT : len;
818 		}
819 
820 		if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGPHYS(0))) {
821 			int len;
822 			if (!hid->phys)
823 				return 0;
824 			len = strlen(hid->phys) + 1;
825 			if (len > _IOC_SIZE(cmd))
826 				len = _IOC_SIZE(cmd);
827 			return copy_to_user(user_arg, hid->phys, len) ?
828 				-EFAULT : len;
829 		}
830 	}
831 	return -EINVAL;
832 }
833 
834 #ifdef CONFIG_COMPAT
835 static long hiddev_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
836 {
837 	return hiddev_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
838 }
839 #endif
840 
841 static const struct file_operations hiddev_fops = {
842 	.owner =	THIS_MODULE,
843 	.read =		hiddev_read,
844 	.write =	hiddev_write,
845 	.poll =		hiddev_poll,
846 	.open =		hiddev_open,
847 	.release =	hiddev_release,
848 	.unlocked_ioctl =	hiddev_ioctl,
849 	.fasync =	hiddev_fasync,
850 #ifdef CONFIG_COMPAT
851 	.compat_ioctl	= hiddev_compat_ioctl,
852 #endif
853 };
854 
855 static char *hiddev_devnode(struct device *dev, mode_t *mode)
856 {
857 	return kasprintf(GFP_KERNEL, "usb/%s", dev_name(dev));
858 }
859 
860 static struct usb_class_driver hiddev_class = {
861 	.name =		"hiddev%d",
862 	.devnode =	hiddev_devnode,
863 	.fops =		&hiddev_fops,
864 	.minor_base =	HIDDEV_MINOR_BASE,
865 };
866 
867 /*
868  * This is where hid.c calls us to connect a hid device to the hiddev driver
869  */
870 int hiddev_connect(struct hid_device *hid, unsigned int force)
871 {
872 	struct hiddev *hiddev;
873 	struct usbhid_device *usbhid = hid->driver_data;
874 	int retval;
875 
876 	if (!force) {
877 		unsigned int i;
878 		for (i = 0; i < hid->maxcollection; i++)
879 			if (hid->collection[i].type ==
880 			    HID_COLLECTION_APPLICATION &&
881 			    !IS_INPUT_APPLICATION(hid->collection[i].usage))
882 				break;
883 
884 		if (i == hid->maxcollection)
885 			return -1;
886 	}
887 
888 	if (!(hiddev = kzalloc(sizeof(struct hiddev), GFP_KERNEL)))
889 		return -1;
890 
891 	init_waitqueue_head(&hiddev->wait);
892 	INIT_LIST_HEAD(&hiddev->list);
893 	spin_lock_init(&hiddev->list_lock);
894 	mutex_init(&hiddev->existancelock);
895 	hid->hiddev = hiddev;
896 	hiddev->hid = hid;
897 	hiddev->exist = 1;
898 
899 	/* when lock_kernel() usage is fixed in usb_open(),
900 	 * we could also fix it here */
901 	lock_kernel();
902 	retval = usb_register_dev(usbhid->intf, &hiddev_class);
903 	if (retval) {
904 		err_hid("Not able to get a minor for this device.");
905 		hid->hiddev = NULL;
906 		unlock_kernel();
907 		kfree(hiddev);
908 		return -1;
909 	} else {
910 		hid->minor = usbhid->intf->minor;
911 		hiddev_table[usbhid->intf->minor - HIDDEV_MINOR_BASE] = hiddev;
912 	}
913 	unlock_kernel();
914 
915 	return 0;
916 }
917 
918 /*
919  * This is where hid.c calls us to disconnect a hiddev device from the
920  * corresponding hid device (usually because the usb device has disconnected)
921  */
922 static struct usb_class_driver hiddev_class;
923 void hiddev_disconnect(struct hid_device *hid)
924 {
925 	struct hiddev *hiddev = hid->hiddev;
926 	struct usbhid_device *usbhid = hid->driver_data;
927 
928 	mutex_lock(&hiddev->existancelock);
929 	hiddev->exist = 0;
930 	mutex_unlock(&hiddev->existancelock);
931 
932 	hiddev_table[hiddev->hid->minor - HIDDEV_MINOR_BASE] = NULL;
933 	usb_deregister_dev(usbhid->intf, &hiddev_class);
934 
935 	if (hiddev->open) {
936 		usbhid_close(hiddev->hid);
937 		wake_up_interruptible(&hiddev->wait);
938 	} else {
939 		kfree(hiddev);
940 	}
941 }
942 
943 /* Currently this driver is a USB driver.  It's not a conventional one in
944  * the sense that it doesn't probe at the USB level.  Instead it waits to
945  * be connected by HID through the hiddev_connect / hiddev_disconnect
946  * routines.  The reason to register as a USB device is to gain part of the
947  * minor number space from the USB major.
948  *
949  * In theory, should the HID code be generalized to more than one physical
950  * medium (say, IEEE 1384), this driver will probably need to register its
951  * own major number, and in doing so, no longer need to register with USB.
952  * At that point the probe routine and hiddev_driver struct below will no
953  * longer be useful.
954  */
955 
956 
957 /* We never attach in this manner, and rely on HID to connect us.  This
958  * is why there is no disconnect routine defined in the usb_driver either.
959  */
960 static int hiddev_usbd_probe(struct usb_interface *intf,
961 			     const struct usb_device_id *hiddev_info)
962 {
963 	return -ENODEV;
964 }
965 
966 static /* const */ struct usb_driver hiddev_driver = {
967 	.name =		"hiddev",
968 	.probe =	hiddev_usbd_probe,
969 };
970 
971 int __init hiddev_init(void)
972 {
973 	return usb_register(&hiddev_driver);
974 }
975 
976 void hiddev_exit(void)
977 {
978 	usb_deregister(&hiddev_driver);
979 }
980