hiddev.c revision 8fe294caf8c868edd9046251824a0af91991bf43
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
49struct 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
59struct 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
70static struct usb_driver hiddev_driver;
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 */
78static struct hid_report *
79hiddev_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 */
131static struct hid_field *
132hiddev_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
163static 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 */
189void 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}
207EXPORT_SYMBOL_GPL(hiddev_hid_event);
208
209void 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 */
228static 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 */
239static 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 */
265static int hiddev_open(struct inode *inode, struct file *file)
266{
267	struct hiddev_list *list;
268	struct usb_interface *intf;
269	struct hid_device *hid;
270	struct hiddev *hiddev;
271	int res;
272
273	intf = usbhid_find_interface(iminor(inode));
274	if (!intf)
275		return -ENODEV;
276	hid = usb_get_intfdata(intf);
277	hiddev = hid->hiddev;
278
279	if (!(list = kzalloc(sizeof(struct hiddev_list), GFP_KERNEL)))
280		return -ENOMEM;
281	mutex_init(&list->thread_lock);
282	list->hiddev = hiddev;
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->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->list);
304	spin_unlock_irq(&list->hiddev->list_lock);
305
306	if (!list->hiddev->open++)
307		if (list->hiddev->exist) {
308			struct hid_device *hid = hiddev->hid;
309			res = usbhid_get_power(hid);
310			if (res < 0) {
311				res = -EIO;
312				goto bail;
313			}
314			usbhid_open(hid);
315		}
316	return 0;
317bail:
318	file->private_data = NULL;
319	kfree(list);
320	return res;
321}
322
323/*
324 * "write" file op
325 */
326static 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 */
334static 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 */
425static 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 */
440static 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	uref = &uref_multi->uref;
454	if (cmd == HIDIOCGUSAGES || cmd == HIDIOCSUSAGES) {
455		if (copy_from_user(uref_multi, user_arg,
456				   sizeof(*uref_multi)))
457			goto fault;
458	} else {
459		if (copy_from_user(uref, user_arg, sizeof(*uref)))
460			goto fault;
461	}
462
463	switch (cmd) {
464	case HIDIOCGUCODE:
465		rinfo.report_type = uref->report_type;
466		rinfo.report_id = uref->report_id;
467		if ((report = hiddev_lookup_report(hid, &rinfo)) == NULL)
468			goto inval;
469
470		if (uref->field_index >= report->maxfield)
471			goto inval;
472
473		field = report->field[uref->field_index];
474		if (uref->usage_index >= field->maxusage)
475			goto inval;
476
477		uref->usage_code = field->usage[uref->usage_index].hid;
478
479		if (copy_to_user(user_arg, uref, sizeof(*uref)))
480			goto fault;
481
482		goto goodreturn;
483
484	default:
485		if (cmd != HIDIOCGUSAGE &&
486		    cmd != HIDIOCGUSAGES &&
487		    uref->report_type == HID_REPORT_TYPE_INPUT)
488			goto inval;
489
490		if (uref->report_id == HID_REPORT_ID_UNKNOWN) {
491			field = hiddev_lookup_usage(hid, uref);
492			if (field == NULL)
493				goto inval;
494		} else {
495			rinfo.report_type = uref->report_type;
496			rinfo.report_id = uref->report_id;
497			if ((report = hiddev_lookup_report(hid, &rinfo)) == NULL)
498				goto inval;
499
500			if (uref->field_index >= report->maxfield)
501				goto inval;
502
503			field = report->field[uref->field_index];
504
505			if (cmd == HIDIOCGCOLLECTIONINDEX) {
506				if (uref->usage_index >= field->maxusage)
507					goto inval;
508			} else if (uref->usage_index >= field->report_count)
509				goto inval;
510
511			else if ((cmd == HIDIOCGUSAGES || cmd == HIDIOCSUSAGES) &&
512				 (uref_multi->num_values > HID_MAX_MULTI_USAGES ||
513				  uref->usage_index + uref_multi->num_values > field->report_count))
514				goto inval;
515			}
516
517		switch (cmd) {
518		case HIDIOCGUSAGE:
519			uref->value = field->value[uref->usage_index];
520			if (copy_to_user(user_arg, uref, sizeof(*uref)))
521				goto fault;
522			goto goodreturn;
523
524		case HIDIOCSUSAGE:
525			field->value[uref->usage_index] = uref->value;
526			goto goodreturn;
527
528		case HIDIOCGCOLLECTIONINDEX:
529			i = field->usage[uref->usage_index].collection_index;
530			kfree(uref_multi);
531			return i;
532		case HIDIOCGUSAGES:
533			for (i = 0; i < uref_multi->num_values; i++)
534				uref_multi->values[i] =
535				    field->value[uref->usage_index + i];
536			if (copy_to_user(user_arg, uref_multi,
537					 sizeof(*uref_multi)))
538				goto fault;
539			goto goodreturn;
540		case HIDIOCSUSAGES:
541			for (i = 0; i < uref_multi->num_values; i++)
542				field->value[uref->usage_index + i] =
543				    uref_multi->values[i];
544			goto goodreturn;
545		}
546
547goodreturn:
548		kfree(uref_multi);
549		return 0;
550fault:
551		kfree(uref_multi);
552		return -EFAULT;
553inval:
554		kfree(uref_multi);
555		return -EINVAL;
556	}
557}
558
559static noinline int hiddev_ioctl_string(struct hiddev *hiddev, unsigned int cmd, void __user *user_arg)
560{
561	struct hid_device *hid = hiddev->hid;
562	struct usb_device *dev = hid_to_usb_dev(hid);
563	int idx, len;
564	char *buf;
565
566	if (get_user(idx, (int __user *)user_arg))
567		return -EFAULT;
568
569	if ((buf = kmalloc(HID_STRING_SIZE, GFP_KERNEL)) == NULL)
570		return -ENOMEM;
571
572	if ((len = usb_string(dev, idx, buf, HID_STRING_SIZE-1)) < 0) {
573		kfree(buf);
574		return -EINVAL;
575	}
576
577	if (copy_to_user(user_arg+sizeof(int), buf, len+1)) {
578		kfree(buf);
579		return -EFAULT;
580	}
581
582	kfree(buf);
583
584	return len;
585}
586
587static long hiddev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
588{
589	struct hiddev_list *list = file->private_data;
590	struct hiddev *hiddev = list->hiddev;
591	struct hid_device *hid = hiddev->hid;
592	struct usb_device *dev;
593	struct hiddev_collection_info cinfo;
594	struct hiddev_report_info rinfo;
595	struct hiddev_field_info finfo;
596	struct hiddev_devinfo dinfo;
597	struct hid_report *report;
598	struct hid_field *field;
599	struct usbhid_device *usbhid = hid->driver_data;
600	void __user *user_arg = (void __user *)arg;
601	int i, r;
602
603	/* Called without BKL by compat methods so no BKL taken */
604
605	/* FIXME: Who or what stop this racing with a disconnect ?? */
606	if (!hiddev->exist || !hid)
607		return -EIO;
608
609	dev = hid_to_usb_dev(hid);
610
611	switch (cmd) {
612
613	case HIDIOCGVERSION:
614		return put_user(HID_VERSION, (int __user *)arg);
615
616	case HIDIOCAPPLICATION:
617		if (arg < 0 || arg >= hid->maxapplication)
618			return -EINVAL;
619
620		for (i = 0; i < hid->maxcollection; i++)
621			if (hid->collection[i].type ==
622			    HID_COLLECTION_APPLICATION && arg-- == 0)
623				break;
624
625		if (i == hid->maxcollection)
626			return -EINVAL;
627
628		return hid->collection[i].usage;
629
630	case HIDIOCGDEVINFO:
631		dinfo.bustype = BUS_USB;
632		dinfo.busnum = dev->bus->busnum;
633		dinfo.devnum = dev->devnum;
634		dinfo.ifnum = usbhid->ifnum;
635		dinfo.vendor = le16_to_cpu(dev->descriptor.idVendor);
636		dinfo.product = le16_to_cpu(dev->descriptor.idProduct);
637		dinfo.version = le16_to_cpu(dev->descriptor.bcdDevice);
638		dinfo.num_applications = hid->maxapplication;
639		if (copy_to_user(user_arg, &dinfo, sizeof(dinfo)))
640			return -EFAULT;
641
642		return 0;
643
644	case HIDIOCGFLAG:
645		if (put_user(list->flags, (int __user *)arg))
646			return -EFAULT;
647
648		return 0;
649
650	case HIDIOCSFLAG:
651		{
652			int newflags;
653			if (get_user(newflags, (int __user *)arg))
654				return -EFAULT;
655
656			if ((newflags & ~HIDDEV_FLAGS) != 0 ||
657			    ((newflags & HIDDEV_FLAG_REPORT) != 0 &&
658			     (newflags & HIDDEV_FLAG_UREF) == 0))
659				return -EINVAL;
660
661			list->flags = newflags;
662
663			return 0;
664		}
665
666	case HIDIOCGSTRING:
667		mutex_lock(&hiddev->existancelock);
668		if (hiddev->exist)
669			r = hiddev_ioctl_string(hiddev, cmd, user_arg);
670		else
671			r = -ENODEV;
672		mutex_unlock(&hiddev->existancelock);
673		return r;
674
675	case HIDIOCINITREPORT:
676		mutex_lock(&hiddev->existancelock);
677		if (!hiddev->exist) {
678			mutex_unlock(&hiddev->existancelock);
679			return -ENODEV;
680		}
681		usbhid_init_reports(hid);
682		mutex_unlock(&hiddev->existancelock);
683
684		return 0;
685
686	case HIDIOCGREPORT:
687		if (copy_from_user(&rinfo, user_arg, sizeof(rinfo)))
688			return -EFAULT;
689
690		if (rinfo.report_type == HID_REPORT_TYPE_OUTPUT)
691			return -EINVAL;
692
693		if ((report = hiddev_lookup_report(hid, &rinfo)) == NULL)
694			return -EINVAL;
695
696		mutex_lock(&hiddev->existancelock);
697		if (hiddev->exist) {
698			usbhid_submit_report(hid, report, USB_DIR_IN);
699			usbhid_wait_io(hid);
700		}
701		mutex_unlock(&hiddev->existancelock);
702
703		return 0;
704
705	case HIDIOCSREPORT:
706		if (copy_from_user(&rinfo, user_arg, sizeof(rinfo)))
707			return -EFAULT;
708
709		if (rinfo.report_type == HID_REPORT_TYPE_INPUT)
710			return -EINVAL;
711
712		if ((report = hiddev_lookup_report(hid, &rinfo)) == NULL)
713			return -EINVAL;
714
715		mutex_lock(&hiddev->existancelock);
716		if (hiddev->exist) {
717			usbhid_submit_report(hid, report, USB_DIR_OUT);
718			usbhid_wait_io(hid);
719		}
720		mutex_unlock(&hiddev->existancelock);
721
722		return 0;
723
724	case HIDIOCGREPORTINFO:
725		if (copy_from_user(&rinfo, user_arg, sizeof(rinfo)))
726			return -EFAULT;
727
728		if ((report = hiddev_lookup_report(hid, &rinfo)) == NULL)
729			return -EINVAL;
730
731		rinfo.num_fields = report->maxfield;
732
733		if (copy_to_user(user_arg, &rinfo, sizeof(rinfo)))
734			return -EFAULT;
735
736		return 0;
737
738	case HIDIOCGFIELDINFO:
739		if (copy_from_user(&finfo, user_arg, sizeof(finfo)))
740			return -EFAULT;
741		rinfo.report_type = finfo.report_type;
742		rinfo.report_id = finfo.report_id;
743		if ((report = hiddev_lookup_report(hid, &rinfo)) == NULL)
744			return -EINVAL;
745
746		if (finfo.field_index >= report->maxfield)
747			return -EINVAL;
748
749		field = report->field[finfo.field_index];
750		memset(&finfo, 0, sizeof(finfo));
751		finfo.report_type = rinfo.report_type;
752		finfo.report_id = rinfo.report_id;
753		finfo.field_index = field->report_count - 1;
754		finfo.maxusage = field->maxusage;
755		finfo.flags = field->flags;
756		finfo.physical = field->physical;
757		finfo.logical = field->logical;
758		finfo.application = field->application;
759		finfo.logical_minimum = field->logical_minimum;
760		finfo.logical_maximum = field->logical_maximum;
761		finfo.physical_minimum = field->physical_minimum;
762		finfo.physical_maximum = field->physical_maximum;
763		finfo.unit_exponent = field->unit_exponent;
764		finfo.unit = field->unit;
765
766		if (copy_to_user(user_arg, &finfo, sizeof(finfo)))
767			return -EFAULT;
768
769		return 0;
770
771	case HIDIOCGUCODE:
772		/* fall through */
773	case HIDIOCGUSAGE:
774	case HIDIOCSUSAGE:
775	case HIDIOCGUSAGES:
776	case HIDIOCSUSAGES:
777	case HIDIOCGCOLLECTIONINDEX:
778		mutex_lock(&hiddev->existancelock);
779		if (hiddev->exist)
780			r = hiddev_ioctl_usage(hiddev, cmd, user_arg);
781		else
782			r = -ENODEV;
783		mutex_unlock(&hiddev->existancelock);
784		return r;
785
786	case HIDIOCGCOLLECTIONINFO:
787		if (copy_from_user(&cinfo, user_arg, sizeof(cinfo)))
788			return -EFAULT;
789
790		if (cinfo.index >= hid->maxcollection)
791			return -EINVAL;
792
793		cinfo.type = hid->collection[cinfo.index].type;
794		cinfo.usage = hid->collection[cinfo.index].usage;
795		cinfo.level = hid->collection[cinfo.index].level;
796
797		if (copy_to_user(user_arg, &cinfo, sizeof(cinfo)))
798			return -EFAULT;
799		return 0;
800
801	default:
802
803		if (_IOC_TYPE(cmd) != 'H' || _IOC_DIR(cmd) != _IOC_READ)
804			return -EINVAL;
805
806		if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGNAME(0))) {
807			int len;
808			if (!hid->name)
809				return 0;
810			len = strlen(hid->name) + 1;
811			if (len > _IOC_SIZE(cmd))
812				 len = _IOC_SIZE(cmd);
813			return copy_to_user(user_arg, hid->name, len) ?
814				-EFAULT : len;
815		}
816
817		if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGPHYS(0))) {
818			int len;
819			if (!hid->phys)
820				return 0;
821			len = strlen(hid->phys) + 1;
822			if (len > _IOC_SIZE(cmd))
823				len = _IOC_SIZE(cmd);
824			return copy_to_user(user_arg, hid->phys, len) ?
825				-EFAULT : len;
826		}
827	}
828	return -EINVAL;
829}
830
831#ifdef CONFIG_COMPAT
832static long hiddev_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
833{
834	return hiddev_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
835}
836#endif
837
838static const struct file_operations hiddev_fops = {
839	.owner =	THIS_MODULE,
840	.read =		hiddev_read,
841	.write =	hiddev_write,
842	.poll =		hiddev_poll,
843	.open =		hiddev_open,
844	.release =	hiddev_release,
845	.unlocked_ioctl =	hiddev_ioctl,
846	.fasync =	hiddev_fasync,
847#ifdef CONFIG_COMPAT
848	.compat_ioctl	= hiddev_compat_ioctl,
849#endif
850};
851
852static char *hiddev_devnode(struct device *dev, mode_t *mode)
853{
854	return kasprintf(GFP_KERNEL, "usb/%s", dev_name(dev));
855}
856
857static struct usb_class_driver hiddev_class = {
858	.name =		"hiddev%d",
859	.devnode =	hiddev_devnode,
860	.fops =		&hiddev_fops,
861	.minor_base =	HIDDEV_MINOR_BASE,
862};
863
864/*
865 * This is where hid.c calls us to connect a hid device to the hiddev driver
866 */
867int hiddev_connect(struct hid_device *hid, unsigned int force)
868{
869	struct hiddev *hiddev;
870	struct usbhid_device *usbhid = hid->driver_data;
871	int retval;
872
873	if (!force) {
874		unsigned int i;
875		for (i = 0; i < hid->maxcollection; i++)
876			if (hid->collection[i].type ==
877			    HID_COLLECTION_APPLICATION &&
878			    !IS_INPUT_APPLICATION(hid->collection[i].usage))
879				break;
880
881		if (i == hid->maxcollection)
882			return -1;
883	}
884
885	if (!(hiddev = kzalloc(sizeof(struct hiddev), GFP_KERNEL)))
886		return -1;
887
888	init_waitqueue_head(&hiddev->wait);
889	INIT_LIST_HEAD(&hiddev->list);
890	spin_lock_init(&hiddev->list_lock);
891	mutex_init(&hiddev->existancelock);
892	hid->hiddev = hiddev;
893	hiddev->hid = hid;
894	hiddev->exist = 1;
895	retval = usb_register_dev(usbhid->intf, &hiddev_class);
896	if (retval) {
897		err_hid("Not able to get a minor for this device.");
898		hid->hiddev = NULL;
899		kfree(hiddev);
900		return -1;
901	}
902	return 0;
903}
904
905/*
906 * This is where hid.c calls us to disconnect a hiddev device from the
907 * corresponding hid device (usually because the usb device has disconnected)
908 */
909static struct usb_class_driver hiddev_class;
910void hiddev_disconnect(struct hid_device *hid)
911{
912	struct hiddev *hiddev = hid->hiddev;
913	struct usbhid_device *usbhid = hid->driver_data;
914
915	mutex_lock(&hiddev->existancelock);
916	hiddev->exist = 0;
917	mutex_unlock(&hiddev->existancelock);
918
919	usb_deregister_dev(usbhid->intf, &hiddev_class);
920
921	if (hiddev->open) {
922		usbhid_close(hiddev->hid);
923		wake_up_interruptible(&hiddev->wait);
924	} else {
925		kfree(hiddev);
926	}
927}
928
929/* Currently this driver is a USB driver.  It's not a conventional one in
930 * the sense that it doesn't probe at the USB level.  Instead it waits to
931 * be connected by HID through the hiddev_connect / hiddev_disconnect
932 * routines.  The reason to register as a USB device is to gain part of the
933 * minor number space from the USB major.
934 *
935 * In theory, should the HID code be generalized to more than one physical
936 * medium (say, IEEE 1384), this driver will probably need to register its
937 * own major number, and in doing so, no longer need to register with USB.
938 * At that point the probe routine and hiddev_driver struct below will no
939 * longer be useful.
940 */
941
942
943/* We never attach in this manner, and rely on HID to connect us.  This
944 * is why there is no disconnect routine defined in the usb_driver either.
945 */
946static int hiddev_usbd_probe(struct usb_interface *intf,
947			     const struct usb_device_id *hiddev_info)
948{
949	return -ENODEV;
950}
951
952static /* const */ struct usb_driver hiddev_driver = {
953	.name =		"hiddev",
954	.probe =	hiddev_usbd_probe,
955};
956
957int __init hiddev_init(void)
958{
959	return usb_register(&hiddev_driver);
960}
961
962void hiddev_exit(void)
963{
964	usb_deregister(&hiddev_driver);
965}
966