xref: /openbmc/linux/drivers/hid/hid-core.c (revision 64c70b1c)
1 /*
2  *  HID support for Linux
3  *
4  *  Copyright (c) 1999 Andreas Gal
5  *  Copyright (c) 2000-2005 Vojtech Pavlik <vojtech@suse.cz>
6  *  Copyright (c) 2005 Michael Haboustak <mike-@cinci.rr.com> for Concept2, Inc
7  *  Copyright (c) 2006-2007 Jiri Kosina
8  */
9 
10 /*
11  * This program is free software; you can redistribute it and/or modify it
12  * under the terms of the GNU General Public License as published by the Free
13  * Software Foundation; either version 2 of the License, or (at your option)
14  * any later version.
15  */
16 
17 #include <linux/module.h>
18 #include <linux/slab.h>
19 #include <linux/init.h>
20 #include <linux/kernel.h>
21 #include <linux/list.h>
22 #include <linux/mm.h>
23 #include <linux/spinlock.h>
24 #include <asm/unaligned.h>
25 #include <asm/byteorder.h>
26 #include <linux/input.h>
27 #include <linux/wait.h>
28 #include <linux/vmalloc.h>
29 
30 #include <linux/hid.h>
31 #include <linux/hiddev.h>
32 #include <linux/hid-debug.h>
33 
34 /*
35  * Version Information
36  */
37 
38 #define DRIVER_VERSION "v2.6"
39 #define DRIVER_AUTHOR "Andreas Gal, Vojtech Pavlik, Jiri Kosina"
40 #define DRIVER_DESC "HID core driver"
41 #define DRIVER_LICENSE "GPL"
42 
43 #ifdef CONFIG_HID_DEBUG
44 int hid_debug = 0;
45 module_param_named(debug, hid_debug, bool, 0600);
46 MODULE_PARM_DESC(debug, "Turn HID debugging mode on and off");
47 EXPORT_SYMBOL_GPL(hid_debug);
48 #endif
49 
50 /*
51  * Register a new report for a device.
52  */
53 
54 static struct hid_report *hid_register_report(struct hid_device *device, unsigned type, unsigned id)
55 {
56 	struct hid_report_enum *report_enum = device->report_enum + type;
57 	struct hid_report *report;
58 
59 	if (report_enum->report_id_hash[id])
60 		return report_enum->report_id_hash[id];
61 
62 	if (!(report = kzalloc(sizeof(struct hid_report), GFP_KERNEL)))
63 		return NULL;
64 
65 	if (id != 0)
66 		report_enum->numbered = 1;
67 
68 	report->id = id;
69 	report->type = type;
70 	report->size = 0;
71 	report->device = device;
72 	report_enum->report_id_hash[id] = report;
73 
74 	list_add_tail(&report->list, &report_enum->report_list);
75 
76 	return report;
77 }
78 
79 /*
80  * Register a new field for this report.
81  */
82 
83 static struct hid_field *hid_register_field(struct hid_report *report, unsigned usages, unsigned values)
84 {
85 	struct hid_field *field;
86 
87 	if (report->maxfield == HID_MAX_FIELDS) {
88 		dbg_hid("too many fields in report\n");
89 		return NULL;
90 	}
91 
92 	if (!(field = kzalloc(sizeof(struct hid_field) + usages * sizeof(struct hid_usage)
93 		+ values * sizeof(unsigned), GFP_KERNEL))) return NULL;
94 
95 	field->index = report->maxfield++;
96 	report->field[field->index] = field;
97 	field->usage = (struct hid_usage *)(field + 1);
98 	field->value = (unsigned *)(field->usage + usages);
99 	field->report = report;
100 
101 	return field;
102 }
103 
104 /*
105  * Open a collection. The type/usage is pushed on the stack.
106  */
107 
108 static int open_collection(struct hid_parser *parser, unsigned type)
109 {
110 	struct hid_collection *collection;
111 	unsigned usage;
112 
113 	usage = parser->local.usage[0];
114 
115 	if (parser->collection_stack_ptr == HID_COLLECTION_STACK_SIZE) {
116 		dbg_hid("collection stack overflow\n");
117 		return -1;
118 	}
119 
120 	if (parser->device->maxcollection == parser->device->collection_size) {
121 		collection = kmalloc(sizeof(struct hid_collection) *
122 				parser->device->collection_size * 2, GFP_KERNEL);
123 		if (collection == NULL) {
124 			dbg_hid("failed to reallocate collection array\n");
125 			return -1;
126 		}
127 		memcpy(collection, parser->device->collection,
128 			sizeof(struct hid_collection) *
129 			parser->device->collection_size);
130 		memset(collection + parser->device->collection_size, 0,
131 			sizeof(struct hid_collection) *
132 			parser->device->collection_size);
133 		kfree(parser->device->collection);
134 		parser->device->collection = collection;
135 		parser->device->collection_size *= 2;
136 	}
137 
138 	parser->collection_stack[parser->collection_stack_ptr++] =
139 		parser->device->maxcollection;
140 
141 	collection = parser->device->collection +
142 		parser->device->maxcollection++;
143 	collection->type = type;
144 	collection->usage = usage;
145 	collection->level = parser->collection_stack_ptr - 1;
146 
147 	if (type == HID_COLLECTION_APPLICATION)
148 		parser->device->maxapplication++;
149 
150 	return 0;
151 }
152 
153 /*
154  * Close a collection.
155  */
156 
157 static int close_collection(struct hid_parser *parser)
158 {
159 	if (!parser->collection_stack_ptr) {
160 		dbg_hid("collection stack underflow\n");
161 		return -1;
162 	}
163 	parser->collection_stack_ptr--;
164 	return 0;
165 }
166 
167 /*
168  * Climb up the stack, search for the specified collection type
169  * and return the usage.
170  */
171 
172 static unsigned hid_lookup_collection(struct hid_parser *parser, unsigned type)
173 {
174 	int n;
175 	for (n = parser->collection_stack_ptr - 1; n >= 0; n--)
176 		if (parser->device->collection[parser->collection_stack[n]].type == type)
177 			return parser->device->collection[parser->collection_stack[n]].usage;
178 	return 0; /* we know nothing about this usage type */
179 }
180 
181 /*
182  * Add a usage to the temporary parser table.
183  */
184 
185 static int hid_add_usage(struct hid_parser *parser, unsigned usage)
186 {
187 	if (parser->local.usage_index >= HID_MAX_USAGES) {
188 		dbg_hid("usage index exceeded\n");
189 		return -1;
190 	}
191 	parser->local.usage[parser->local.usage_index] = usage;
192 	parser->local.collection_index[parser->local.usage_index] =
193 		parser->collection_stack_ptr ?
194 		parser->collection_stack[parser->collection_stack_ptr - 1] : 0;
195 	parser->local.usage_index++;
196 	return 0;
197 }
198 
199 /*
200  * Register a new field for this report.
201  */
202 
203 static int hid_add_field(struct hid_parser *parser, unsigned report_type, unsigned flags)
204 {
205 	struct hid_report *report;
206 	struct hid_field *field;
207 	int usages;
208 	unsigned offset;
209 	int i;
210 
211 	if (!(report = hid_register_report(parser->device, report_type, parser->global.report_id))) {
212 		dbg_hid("hid_register_report failed\n");
213 		return -1;
214 	}
215 
216 	if (parser->global.logical_maximum < parser->global.logical_minimum) {
217 		dbg_hid("logical range invalid %d %d\n", parser->global.logical_minimum, parser->global.logical_maximum);
218 		return -1;
219 	}
220 
221 	offset = report->size;
222 	report->size += parser->global.report_size * parser->global.report_count;
223 
224 	if (!parser->local.usage_index) /* Ignore padding fields */
225 		return 0;
226 
227 	usages = max_t(int, parser->local.usage_index, parser->global.report_count);
228 
229 	if ((field = hid_register_field(report, usages, parser->global.report_count)) == NULL)
230 		return 0;
231 
232 	field->physical = hid_lookup_collection(parser, HID_COLLECTION_PHYSICAL);
233 	field->logical = hid_lookup_collection(parser, HID_COLLECTION_LOGICAL);
234 	field->application = hid_lookup_collection(parser, HID_COLLECTION_APPLICATION);
235 
236 	for (i = 0; i < usages; i++) {
237 		int j = i;
238 		/* Duplicate the last usage we parsed if we have excess values */
239 		if (i >= parser->local.usage_index)
240 			j = parser->local.usage_index - 1;
241 		field->usage[i].hid = parser->local.usage[j];
242 		field->usage[i].collection_index =
243 			parser->local.collection_index[j];
244 	}
245 
246 	field->maxusage = usages;
247 	field->flags = flags;
248 	field->report_offset = offset;
249 	field->report_type = report_type;
250 	field->report_size = parser->global.report_size;
251 	field->report_count = parser->global.report_count;
252 	field->logical_minimum = parser->global.logical_minimum;
253 	field->logical_maximum = parser->global.logical_maximum;
254 	field->physical_minimum = parser->global.physical_minimum;
255 	field->physical_maximum = parser->global.physical_maximum;
256 	field->unit_exponent = parser->global.unit_exponent;
257 	field->unit = parser->global.unit;
258 
259 	return 0;
260 }
261 
262 /*
263  * Read data value from item.
264  */
265 
266 static u32 item_udata(struct hid_item *item)
267 {
268 	switch (item->size) {
269 		case 1: return item->data.u8;
270 		case 2: return item->data.u16;
271 		case 4: return item->data.u32;
272 	}
273 	return 0;
274 }
275 
276 static s32 item_sdata(struct hid_item *item)
277 {
278 	switch (item->size) {
279 		case 1: return item->data.s8;
280 		case 2: return item->data.s16;
281 		case 4: return item->data.s32;
282 	}
283 	return 0;
284 }
285 
286 /*
287  * Process a global item.
288  */
289 
290 static int hid_parser_global(struct hid_parser *parser, struct hid_item *item)
291 {
292 	switch (item->tag) {
293 
294 		case HID_GLOBAL_ITEM_TAG_PUSH:
295 
296 			if (parser->global_stack_ptr == HID_GLOBAL_STACK_SIZE) {
297 				dbg_hid("global enviroment stack overflow\n");
298 				return -1;
299 			}
300 
301 			memcpy(parser->global_stack + parser->global_stack_ptr++,
302 				&parser->global, sizeof(struct hid_global));
303 			return 0;
304 
305 		case HID_GLOBAL_ITEM_TAG_POP:
306 
307 			if (!parser->global_stack_ptr) {
308 				dbg_hid("global enviroment stack underflow\n");
309 				return -1;
310 			}
311 
312 			memcpy(&parser->global, parser->global_stack + --parser->global_stack_ptr,
313 				sizeof(struct hid_global));
314 			return 0;
315 
316 		case HID_GLOBAL_ITEM_TAG_USAGE_PAGE:
317 			parser->global.usage_page = item_udata(item);
318 			return 0;
319 
320 		case HID_GLOBAL_ITEM_TAG_LOGICAL_MINIMUM:
321 			parser->global.logical_minimum = item_sdata(item);
322 			return 0;
323 
324 		case HID_GLOBAL_ITEM_TAG_LOGICAL_MAXIMUM:
325 			if (parser->global.logical_minimum < 0)
326 				parser->global.logical_maximum = item_sdata(item);
327 			else
328 				parser->global.logical_maximum = item_udata(item);
329 			return 0;
330 
331 		case HID_GLOBAL_ITEM_TAG_PHYSICAL_MINIMUM:
332 			parser->global.physical_minimum = item_sdata(item);
333 			return 0;
334 
335 		case HID_GLOBAL_ITEM_TAG_PHYSICAL_MAXIMUM:
336 			if (parser->global.physical_minimum < 0)
337 				parser->global.physical_maximum = item_sdata(item);
338 			else
339 				parser->global.physical_maximum = item_udata(item);
340 			return 0;
341 
342 		case HID_GLOBAL_ITEM_TAG_UNIT_EXPONENT:
343 			parser->global.unit_exponent = item_sdata(item);
344 			return 0;
345 
346 		case HID_GLOBAL_ITEM_TAG_UNIT:
347 			parser->global.unit = item_udata(item);
348 			return 0;
349 
350 		case HID_GLOBAL_ITEM_TAG_REPORT_SIZE:
351 			if ((parser->global.report_size = item_udata(item)) > 32) {
352 				dbg_hid("invalid report_size %d\n", parser->global.report_size);
353 				return -1;
354 			}
355 			return 0;
356 
357 		case HID_GLOBAL_ITEM_TAG_REPORT_COUNT:
358 			if ((parser->global.report_count = item_udata(item)) > HID_MAX_USAGES) {
359 				dbg_hid("invalid report_count %d\n", parser->global.report_count);
360 				return -1;
361 			}
362 			return 0;
363 
364 		case HID_GLOBAL_ITEM_TAG_REPORT_ID:
365 			if ((parser->global.report_id = item_udata(item)) == 0) {
366 				dbg_hid("report_id 0 is invalid\n");
367 				return -1;
368 			}
369 			return 0;
370 
371 		default:
372 			dbg_hid("unknown global tag 0x%x\n", item->tag);
373 			return -1;
374 	}
375 }
376 
377 /*
378  * Process a local item.
379  */
380 
381 static int hid_parser_local(struct hid_parser *parser, struct hid_item *item)
382 {
383 	__u32 data;
384 	unsigned n;
385 
386 	if (item->size == 0) {
387 		dbg_hid("item data expected for local item\n");
388 		return -1;
389 	}
390 
391 	data = item_udata(item);
392 
393 	switch (item->tag) {
394 
395 		case HID_LOCAL_ITEM_TAG_DELIMITER:
396 
397 			if (data) {
398 				/*
399 				 * We treat items before the first delimiter
400 				 * as global to all usage sets (branch 0).
401 				 * In the moment we process only these global
402 				 * items and the first delimiter set.
403 				 */
404 				if (parser->local.delimiter_depth != 0) {
405 					dbg_hid("nested delimiters\n");
406 					return -1;
407 				}
408 				parser->local.delimiter_depth++;
409 				parser->local.delimiter_branch++;
410 			} else {
411 				if (parser->local.delimiter_depth < 1) {
412 					dbg_hid("bogus close delimiter\n");
413 					return -1;
414 				}
415 				parser->local.delimiter_depth--;
416 			}
417 			return 1;
418 
419 		case HID_LOCAL_ITEM_TAG_USAGE:
420 
421 			if (parser->local.delimiter_branch > 1) {
422 				dbg_hid("alternative usage ignored\n");
423 				return 0;
424 			}
425 
426 			if (item->size <= 2)
427 				data = (parser->global.usage_page << 16) + data;
428 
429 			return hid_add_usage(parser, data);
430 
431 		case HID_LOCAL_ITEM_TAG_USAGE_MINIMUM:
432 
433 			if (parser->local.delimiter_branch > 1) {
434 				dbg_hid("alternative usage ignored\n");
435 				return 0;
436 			}
437 
438 			if (item->size <= 2)
439 				data = (parser->global.usage_page << 16) + data;
440 
441 			parser->local.usage_minimum = data;
442 			return 0;
443 
444 		case HID_LOCAL_ITEM_TAG_USAGE_MAXIMUM:
445 
446 			if (parser->local.delimiter_branch > 1) {
447 				dbg_hid("alternative usage ignored\n");
448 				return 0;
449 			}
450 
451 			if (item->size <= 2)
452 				data = (parser->global.usage_page << 16) + data;
453 
454 			for (n = parser->local.usage_minimum; n <= data; n++)
455 				if (hid_add_usage(parser, n)) {
456 					dbg_hid("hid_add_usage failed\n");
457 					return -1;
458 				}
459 			return 0;
460 
461 		default:
462 
463 			dbg_hid("unknown local item tag 0x%x\n", item->tag);
464 			return 0;
465 	}
466 	return 0;
467 }
468 
469 /*
470  * Process a main item.
471  */
472 
473 static int hid_parser_main(struct hid_parser *parser, struct hid_item *item)
474 {
475 	__u32 data;
476 	int ret;
477 
478 	data = item_udata(item);
479 
480 	switch (item->tag) {
481 		case HID_MAIN_ITEM_TAG_BEGIN_COLLECTION:
482 			ret = open_collection(parser, data & 0xff);
483 			break;
484 		case HID_MAIN_ITEM_TAG_END_COLLECTION:
485 			ret = close_collection(parser);
486 			break;
487 		case HID_MAIN_ITEM_TAG_INPUT:
488 			ret = hid_add_field(parser, HID_INPUT_REPORT, data);
489 			break;
490 		case HID_MAIN_ITEM_TAG_OUTPUT:
491 			ret = hid_add_field(parser, HID_OUTPUT_REPORT, data);
492 			break;
493 		case HID_MAIN_ITEM_TAG_FEATURE:
494 			ret = hid_add_field(parser, HID_FEATURE_REPORT, data);
495 			break;
496 		default:
497 			dbg_hid("unknown main item tag 0x%x\n", item->tag);
498 			ret = 0;
499 	}
500 
501 	memset(&parser->local, 0, sizeof(parser->local));	/* Reset the local parser environment */
502 
503 	return ret;
504 }
505 
506 /*
507  * Process a reserved item.
508  */
509 
510 static int hid_parser_reserved(struct hid_parser *parser, struct hid_item *item)
511 {
512 	dbg_hid("reserved item type, tag 0x%x\n", item->tag);
513 	return 0;
514 }
515 
516 /*
517  * Free a report and all registered fields. The field->usage and
518  * field->value table's are allocated behind the field, so we need
519  * only to free(field) itself.
520  */
521 
522 static void hid_free_report(struct hid_report *report)
523 {
524 	unsigned n;
525 
526 	for (n = 0; n < report->maxfield; n++)
527 		kfree(report->field[n]);
528 	kfree(report);
529 }
530 
531 /*
532  * Free a device structure, all reports, and all fields.
533  */
534 
535 void hid_free_device(struct hid_device *device)
536 {
537 	unsigned i,j;
538 
539 	for (i = 0; i < HID_REPORT_TYPES; i++) {
540 		struct hid_report_enum *report_enum = device->report_enum + i;
541 
542 		for (j = 0; j < 256; j++) {
543 			struct hid_report *report = report_enum->report_id_hash[j];
544 			if (report)
545 				hid_free_report(report);
546 		}
547 	}
548 
549 	kfree(device->rdesc);
550 	kfree(device->collection);
551 	kfree(device);
552 }
553 EXPORT_SYMBOL_GPL(hid_free_device);
554 
555 /*
556  * Fetch a report description item from the data stream. We support long
557  * items, though they are not used yet.
558  */
559 
560 static u8 *fetch_item(__u8 *start, __u8 *end, struct hid_item *item)
561 {
562 	u8 b;
563 
564 	if ((end - start) <= 0)
565 		return NULL;
566 
567 	b = *start++;
568 
569 	item->type = (b >> 2) & 3;
570 	item->tag  = (b >> 4) & 15;
571 
572 	if (item->tag == HID_ITEM_TAG_LONG) {
573 
574 		item->format = HID_ITEM_FORMAT_LONG;
575 
576 		if ((end - start) < 2)
577 			return NULL;
578 
579 		item->size = *start++;
580 		item->tag  = *start++;
581 
582 		if ((end - start) < item->size)
583 			return NULL;
584 
585 		item->data.longdata = start;
586 		start += item->size;
587 		return start;
588 	}
589 
590 	item->format = HID_ITEM_FORMAT_SHORT;
591 	item->size = b & 3;
592 
593 	switch (item->size) {
594 
595 		case 0:
596 			return start;
597 
598 		case 1:
599 			if ((end - start) < 1)
600 				return NULL;
601 			item->data.u8 = *start++;
602 			return start;
603 
604 		case 2:
605 			if ((end - start) < 2)
606 				return NULL;
607 			item->data.u16 = le16_to_cpu(get_unaligned((__le16*)start));
608 			start = (__u8 *)((__le16 *)start + 1);
609 			return start;
610 
611 		case 3:
612 			item->size++;
613 			if ((end - start) < 4)
614 				return NULL;
615 			item->data.u32 = le32_to_cpu(get_unaligned((__le32*)start));
616 			start = (__u8 *)((__le32 *)start + 1);
617 			return start;
618 	}
619 
620 	return NULL;
621 }
622 
623 /*
624  * Parse a report description into a hid_device structure. Reports are
625  * enumerated, fields are attached to these reports.
626  */
627 
628 struct hid_device *hid_parse_report(__u8 *start, unsigned size)
629 {
630 	struct hid_device *device;
631 	struct hid_parser *parser;
632 	struct hid_item item;
633 	__u8 *end;
634 	unsigned i;
635 	static int (*dispatch_type[])(struct hid_parser *parser,
636 				      struct hid_item *item) = {
637 		hid_parser_main,
638 		hid_parser_global,
639 		hid_parser_local,
640 		hid_parser_reserved
641 	};
642 
643 	if (!(device = kzalloc(sizeof(struct hid_device), GFP_KERNEL)))
644 		return NULL;
645 
646 	if (!(device->collection = kzalloc(sizeof(struct hid_collection) *
647 				   HID_DEFAULT_NUM_COLLECTIONS, GFP_KERNEL))) {
648 		kfree(device);
649 		return NULL;
650 	}
651 	device->collection_size = HID_DEFAULT_NUM_COLLECTIONS;
652 
653 	for (i = 0; i < HID_REPORT_TYPES; i++)
654 		INIT_LIST_HEAD(&device->report_enum[i].report_list);
655 
656 	if (!(device->rdesc = kmalloc(size, GFP_KERNEL))) {
657 		kfree(device->collection);
658 		kfree(device);
659 		return NULL;
660 	}
661 	memcpy(device->rdesc, start, size);
662 	device->rsize = size;
663 
664 	if (!(parser = vmalloc(sizeof(struct hid_parser)))) {
665 		kfree(device->rdesc);
666 		kfree(device->collection);
667 		kfree(device);
668 		return NULL;
669 	}
670 	memset(parser, 0, sizeof(struct hid_parser));
671 	parser->device = device;
672 
673 	end = start + size;
674 	while ((start = fetch_item(start, end, &item)) != NULL) {
675 
676 		if (item.format != HID_ITEM_FORMAT_SHORT) {
677 			dbg_hid("unexpected long global item\n");
678 			hid_free_device(device);
679 			vfree(parser);
680 			return NULL;
681 		}
682 
683 		if (dispatch_type[item.type](parser, &item)) {
684 			dbg_hid("item %u %u %u %u parsing failed\n",
685 				item.format, (unsigned)item.size, (unsigned)item.type, (unsigned)item.tag);
686 			hid_free_device(device);
687 			vfree(parser);
688 			return NULL;
689 		}
690 
691 		if (start == end) {
692 			if (parser->collection_stack_ptr) {
693 				dbg_hid("unbalanced collection at end of report description\n");
694 				hid_free_device(device);
695 				vfree(parser);
696 				return NULL;
697 			}
698 			if (parser->local.delimiter_depth) {
699 				dbg_hid("unbalanced delimiter at end of report description\n");
700 				hid_free_device(device);
701 				vfree(parser);
702 				return NULL;
703 			}
704 			vfree(parser);
705 			return device;
706 		}
707 	}
708 
709 	dbg_hid("item fetching failed at offset %d\n", (int)(end - start));
710 	hid_free_device(device);
711 	vfree(parser);
712 	return NULL;
713 }
714 EXPORT_SYMBOL_GPL(hid_parse_report);
715 
716 /*
717  * Convert a signed n-bit integer to signed 32-bit integer. Common
718  * cases are done through the compiler, the screwed things has to be
719  * done by hand.
720  */
721 
722 static s32 snto32(__u32 value, unsigned n)
723 {
724 	switch (n) {
725 		case 8:  return ((__s8)value);
726 		case 16: return ((__s16)value);
727 		case 32: return ((__s32)value);
728 	}
729 	return value & (1 << (n - 1)) ? value | (-1 << n) : value;
730 }
731 
732 /*
733  * Convert a signed 32-bit integer to a signed n-bit integer.
734  */
735 
736 static u32 s32ton(__s32 value, unsigned n)
737 {
738 	s32 a = value >> (n - 1);
739 	if (a && a != -1)
740 		return value < 0 ? 1 << (n - 1) : (1 << (n - 1)) - 1;
741 	return value & ((1 << n) - 1);
742 }
743 
744 /*
745  * Extract/implement a data field from/to a little endian report (bit array).
746  *
747  * Code sort-of follows HID spec:
748  *     http://www.usb.org/developers/devclass_docs/HID1_11.pdf
749  *
750  * While the USB HID spec allows unlimited length bit fields in "report
751  * descriptors", most devices never use more than 16 bits.
752  * One model of UPS is claimed to report "LINEV" as a 32-bit field.
753  * Search linux-kernel and linux-usb-devel archives for "hid-core extract".
754  */
755 
756 static __inline__ __u32 extract(__u8 *report, unsigned offset, unsigned n)
757 {
758 	u64 x;
759 
760 	WARN_ON(n > 32);
761 
762 	report += offset >> 3;  /* adjust byte index */
763 	offset &= 7;            /* now only need bit offset into one byte */
764 	x = le64_to_cpu(get_unaligned((__le64 *) report));
765 	x = (x >> offset) & ((1ULL << n) - 1);  /* extract bit field */
766 	return (u32) x;
767 }
768 
769 /*
770  * "implement" : set bits in a little endian bit stream.
771  * Same concepts as "extract" (see comments above).
772  * The data mangled in the bit stream remains in little endian
773  * order the whole time. It make more sense to talk about
774  * endianness of register values by considering a register
775  * a "cached" copy of the little endiad bit stream.
776  */
777 static __inline__ void implement(__u8 *report, unsigned offset, unsigned n, __u32 value)
778 {
779 	__le64 x;
780 	u64 m = (1ULL << n) - 1;
781 
782 	WARN_ON(n > 32);
783 
784 	WARN_ON(value > m);
785 	value &= m;
786 
787 	report += offset >> 3;
788 	offset &= 7;
789 
790 	x = get_unaligned((__le64 *)report);
791 	x &= cpu_to_le64(~(m << offset));
792 	x |= cpu_to_le64(((u64) value) << offset);
793 	put_unaligned(x, (__le64 *) report);
794 }
795 
796 /*
797  * Search an array for a value.
798  */
799 
800 static __inline__ int search(__s32 *array, __s32 value, unsigned n)
801 {
802 	while (n--) {
803 		if (*array++ == value)
804 			return 0;
805 	}
806 	return -1;
807 }
808 
809 static void hid_process_event(struct hid_device *hid, struct hid_field *field, struct hid_usage *usage, __s32 value, int interrupt)
810 {
811 	hid_dump_input(usage, value);
812 	if (hid->claimed & HID_CLAIMED_INPUT)
813 		hidinput_hid_event(hid, field, usage, value);
814 	if (hid->claimed & HID_CLAIMED_HIDDEV && interrupt && hid->hiddev_hid_event)
815 		hid->hiddev_hid_event(hid, field, usage, value);
816 }
817 
818 /*
819  * Analyse a received field, and fetch the data from it. The field
820  * content is stored for next report processing (we do differential
821  * reporting to the layer).
822  */
823 
824 void hid_input_field(struct hid_device *hid, struct hid_field *field, __u8 *data, int interrupt)
825 {
826 	unsigned n;
827 	unsigned count = field->report_count;
828 	unsigned offset = field->report_offset;
829 	unsigned size = field->report_size;
830 	__s32 min = field->logical_minimum;
831 	__s32 max = field->logical_maximum;
832 	__s32 *value;
833 
834 	if (!(value = kmalloc(sizeof(__s32) * count, GFP_ATOMIC)))
835 		return;
836 
837 	for (n = 0; n < count; n++) {
838 
839 			value[n] = min < 0 ? snto32(extract(data, offset + n * size, size), size) :
840 						    extract(data, offset + n * size, size);
841 
842 			if (!(field->flags & HID_MAIN_ITEM_VARIABLE) /* Ignore report if ErrorRollOver */
843 			    && value[n] >= min && value[n] <= max
844 			    && field->usage[value[n] - min].hid == HID_UP_KEYBOARD + 1)
845 				goto exit;
846 	}
847 
848 	for (n = 0; n < count; n++) {
849 
850 		if (HID_MAIN_ITEM_VARIABLE & field->flags) {
851 			hid_process_event(hid, field, &field->usage[n], value[n], interrupt);
852 			continue;
853 		}
854 
855 		if (field->value[n] >= min && field->value[n] <= max
856 			&& field->usage[field->value[n] - min].hid
857 			&& search(value, field->value[n], count))
858 				hid_process_event(hid, field, &field->usage[field->value[n] - min], 0, interrupt);
859 
860 		if (value[n] >= min && value[n] <= max
861 			&& field->usage[value[n] - min].hid
862 			&& search(field->value, value[n], count))
863 				hid_process_event(hid, field, &field->usage[value[n] - min], 1, interrupt);
864 	}
865 
866 	memcpy(field->value, value, count * sizeof(__s32));
867 exit:
868 	kfree(value);
869 }
870 EXPORT_SYMBOL_GPL(hid_input_field);
871 
872 /*
873  * Output the field into the report.
874  */
875 
876 static void hid_output_field(struct hid_field *field, __u8 *data)
877 {
878 	unsigned count = field->report_count;
879 	unsigned offset = field->report_offset;
880 	unsigned size = field->report_size;
881 	unsigned bitsused = offset + count * size;
882 	unsigned n;
883 
884 	/* make sure the unused bits in the last byte are zeros */
885 	if (count > 0 && size > 0 && (bitsused % 8) != 0)
886 		data[(bitsused-1)/8] &= (1 << (bitsused % 8)) - 1;
887 
888 	for (n = 0; n < count; n++) {
889 		if (field->logical_minimum < 0)	/* signed values */
890 			implement(data, offset + n * size, size, s32ton(field->value[n], size));
891 		else				/* unsigned values */
892 			implement(data, offset + n * size, size, field->value[n]);
893 	}
894 }
895 
896 /*
897  * Create a report.
898  */
899 
900 void hid_output_report(struct hid_report *report, __u8 *data)
901 {
902 	unsigned n;
903 
904 	if (report->id > 0)
905 		*data++ = report->id;
906 
907 	for (n = 0; n < report->maxfield; n++)
908 		hid_output_field(report->field[n], data);
909 }
910 EXPORT_SYMBOL_GPL(hid_output_report);
911 
912 /*
913  * Set a field value. The report this field belongs to has to be
914  * created and transferred to the device, to set this value in the
915  * device.
916  */
917 
918 int hid_set_field(struct hid_field *field, unsigned offset, __s32 value)
919 {
920 	unsigned size = field->report_size;
921 
922 	hid_dump_input(field->usage + offset, value);
923 
924 	if (offset >= field->report_count) {
925 		dbg_hid("offset (%d) exceeds report_count (%d)\n", offset, field->report_count);
926 		hid_dump_field(field, 8);
927 		return -1;
928 	}
929 	if (field->logical_minimum < 0) {
930 		if (value != snto32(s32ton(value, size), size)) {
931 			dbg_hid("value %d is out of range\n", value);
932 			return -1;
933 		}
934 	}
935 	field->value[offset] = value;
936 	return 0;
937 }
938 EXPORT_SYMBOL_GPL(hid_set_field);
939 
940 int hid_input_report(struct hid_device *hid, int type, u8 *data, int size, int interrupt)
941 {
942 	struct hid_report_enum *report_enum = hid->report_enum + type;
943 	struct hid_report *report;
944 	int n, rsize, i;
945 
946 	if (!hid)
947 		return -ENODEV;
948 
949 	if (!size) {
950 		dbg_hid("empty report\n");
951 		return -1;
952 	}
953 
954 	dbg_hid("report (size %u) (%snumbered)\n", size, report_enum->numbered ? "" : "un");
955 
956 	n = 0;                          /* Normally report number is 0 */
957 	if (report_enum->numbered) {    /* Device uses numbered reports, data[0] is report number */
958 		n = *data++;
959 		size--;
960 	}
961 
962 	/* dump the report descriptor */
963 	dbg_hid("report %d (size %u) = ", n, size);
964 	for (i = 0; i < size; i++)
965 		dbg_hid_line(" %02x", data[i]);
966 	dbg_hid_line("\n");
967 
968 	if (!(report = report_enum->report_id_hash[n])) {
969 		dbg_hid("undefined report_id %d received\n", n);
970 		return -1;
971 	}
972 
973 	rsize = ((report->size - 1) >> 3) + 1;
974 
975 	if (size < rsize) {
976 		dbg_hid("report %d is too short, (%d < %d)\n", report->id, size, rsize);
977 		memset(data + size, 0, rsize - size);
978 	}
979 
980 	if ((hid->claimed & HID_CLAIMED_HIDDEV) && hid->hiddev_report_event)
981 		hid->hiddev_report_event(hid, report);
982 
983 	for (n = 0; n < report->maxfield; n++)
984 		hid_input_field(hid, report->field[n], data, interrupt);
985 
986 	if (hid->claimed & HID_CLAIMED_INPUT)
987 		hidinput_report_event(hid, report);
988 
989 	return 0;
990 }
991 EXPORT_SYMBOL_GPL(hid_input_report);
992 
993 MODULE_LICENSE(DRIVER_LICENSE);
994 
995