xref: /linux/drivers/hid/hid-core.c (revision b48543c451c30387b53ee6e202dda8d5303f6268)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *  HID support for Linux
4  *
5  *  Copyright (c) 1999 Andreas Gal
6  *  Copyright (c) 2000-2005 Vojtech Pavlik <vojtech@suse.cz>
7  *  Copyright (c) 2005 Michael Haboustak <mike-@cinci.rr.com> for Concept2, Inc
8  *  Copyright (c) 2006-2012 Jiri Kosina
9  */
10 
11 /*
12  */
13 
14 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
15 
16 #include <linux/module.h>
17 #include <linux/slab.h>
18 #include <linux/init.h>
19 #include <linux/kernel.h>
20 #include <linux/list.h>
21 #include <linux/mm.h>
22 #include <linux/spinlock.h>
23 #include <asm/unaligned.h>
24 #include <asm/byteorder.h>
25 #include <linux/input.h>
26 #include <linux/wait.h>
27 #include <linux/vmalloc.h>
28 #include <linux/sched.h>
29 #include <linux/semaphore.h>
30 
31 #include <linux/hid.h>
32 #include <linux/hiddev.h>
33 #include <linux/hid-debug.h>
34 #include <linux/hidraw.h>
35 
36 #include "hid-ids.h"
37 
38 /*
39  * Version Information
40  */
41 
42 #define DRIVER_DESC "HID core driver"
43 
44 static int hid_ignore_special_drivers = 0;
45 module_param_named(ignore_special_drivers, hid_ignore_special_drivers, int, 0600);
46 MODULE_PARM_DESC(ignore_special_drivers, "Ignore any special drivers and handle all devices by generic driver");
47 
48 /*
49  * Register a new report for a device.
50  */
51 
52 struct hid_report *hid_register_report(struct hid_device *device,
53 				       enum hid_report_type type, unsigned int id,
54 				       unsigned int application)
55 {
56 	struct hid_report_enum *report_enum = device->report_enum + type;
57 	struct hid_report *report;
58 
59 	if (id >= HID_MAX_IDS)
60 		return NULL;
61 	if (report_enum->report_id_hash[id])
62 		return report_enum->report_id_hash[id];
63 
64 	report = kzalloc(sizeof(struct hid_report), GFP_KERNEL);
65 	if (!report)
66 		return NULL;
67 
68 	if (id != 0)
69 		report_enum->numbered = 1;
70 
71 	report->id = id;
72 	report->type = type;
73 	report->size = 0;
74 	report->device = device;
75 	report->application = application;
76 	report_enum->report_id_hash[id] = report;
77 
78 	list_add_tail(&report->list, &report_enum->report_list);
79 	INIT_LIST_HEAD(&report->field_entry_list);
80 
81 	return report;
82 }
83 EXPORT_SYMBOL_GPL(hid_register_report);
84 
85 /*
86  * Register a new field for this report.
87  */
88 
89 static struct hid_field *hid_register_field(struct hid_report *report, unsigned usages)
90 {
91 	struct hid_field *field;
92 
93 	if (report->maxfield == HID_MAX_FIELDS) {
94 		hid_err(report->device, "too many fields in report\n");
95 		return NULL;
96 	}
97 
98 	field = kvzalloc((sizeof(struct hid_field) +
99 			  usages * sizeof(struct hid_usage) +
100 			  3 * usages * sizeof(unsigned int)), GFP_KERNEL);
101 	if (!field)
102 		return NULL;
103 
104 	field->index = report->maxfield++;
105 	report->field[field->index] = field;
106 	field->usage = (struct hid_usage *)(field + 1);
107 	field->value = (s32 *)(field->usage + usages);
108 	field->new_value = (s32 *)(field->value + usages);
109 	field->usages_priorities = (s32 *)(field->new_value + usages);
110 	field->report = report;
111 
112 	return field;
113 }
114 
115 /*
116  * Open a collection. The type/usage is pushed on the stack.
117  */
118 
119 static int open_collection(struct hid_parser *parser, unsigned type)
120 {
121 	struct hid_collection *collection;
122 	unsigned usage;
123 	int collection_index;
124 
125 	usage = parser->local.usage[0];
126 
127 	if (parser->collection_stack_ptr == parser->collection_stack_size) {
128 		unsigned int *collection_stack;
129 		unsigned int new_size = parser->collection_stack_size +
130 					HID_COLLECTION_STACK_SIZE;
131 
132 		collection_stack = krealloc(parser->collection_stack,
133 					    new_size * sizeof(unsigned int),
134 					    GFP_KERNEL);
135 		if (!collection_stack)
136 			return -ENOMEM;
137 
138 		parser->collection_stack = collection_stack;
139 		parser->collection_stack_size = new_size;
140 	}
141 
142 	if (parser->device->maxcollection == parser->device->collection_size) {
143 		collection = kmalloc(
144 				array3_size(sizeof(struct hid_collection),
145 					    parser->device->collection_size,
146 					    2),
147 				GFP_KERNEL);
148 		if (collection == NULL) {
149 			hid_err(parser->device, "failed to reallocate collection array\n");
150 			return -ENOMEM;
151 		}
152 		memcpy(collection, parser->device->collection,
153 			sizeof(struct hid_collection) *
154 			parser->device->collection_size);
155 		memset(collection + parser->device->collection_size, 0,
156 			sizeof(struct hid_collection) *
157 			parser->device->collection_size);
158 		kfree(parser->device->collection);
159 		parser->device->collection = collection;
160 		parser->device->collection_size *= 2;
161 	}
162 
163 	parser->collection_stack[parser->collection_stack_ptr++] =
164 		parser->device->maxcollection;
165 
166 	collection_index = parser->device->maxcollection++;
167 	collection = parser->device->collection + collection_index;
168 	collection->type = type;
169 	collection->usage = usage;
170 	collection->level = parser->collection_stack_ptr - 1;
171 	collection->parent_idx = (collection->level == 0) ? -1 :
172 		parser->collection_stack[collection->level - 1];
173 
174 	if (type == HID_COLLECTION_APPLICATION)
175 		parser->device->maxapplication++;
176 
177 	return 0;
178 }
179 
180 /*
181  * Close a collection.
182  */
183 
184 static int close_collection(struct hid_parser *parser)
185 {
186 	if (!parser->collection_stack_ptr) {
187 		hid_err(parser->device, "collection stack underflow\n");
188 		return -EINVAL;
189 	}
190 	parser->collection_stack_ptr--;
191 	return 0;
192 }
193 
194 /*
195  * Climb up the stack, search for the specified collection type
196  * and return the usage.
197  */
198 
199 static unsigned hid_lookup_collection(struct hid_parser *parser, unsigned type)
200 {
201 	struct hid_collection *collection = parser->device->collection;
202 	int n;
203 
204 	for (n = parser->collection_stack_ptr - 1; n >= 0; n--) {
205 		unsigned index = parser->collection_stack[n];
206 		if (collection[index].type == type)
207 			return collection[index].usage;
208 	}
209 	return 0; /* we know nothing about this usage type */
210 }
211 
212 /*
213  * Concatenate usage which defines 16 bits or less with the
214  * currently defined usage page to form a 32 bit usage
215  */
216 
217 static void complete_usage(struct hid_parser *parser, unsigned int index)
218 {
219 	parser->local.usage[index] &= 0xFFFF;
220 	parser->local.usage[index] |=
221 		(parser->global.usage_page & 0xFFFF) << 16;
222 }
223 
224 /*
225  * Add a usage to the temporary parser table.
226  */
227 
228 static int hid_add_usage(struct hid_parser *parser, unsigned usage, u8 size)
229 {
230 	if (parser->local.usage_index >= HID_MAX_USAGES) {
231 		hid_err(parser->device, "usage index exceeded\n");
232 		return -1;
233 	}
234 	parser->local.usage[parser->local.usage_index] = usage;
235 
236 	/*
237 	 * If Usage item only includes usage id, concatenate it with
238 	 * currently defined usage page
239 	 */
240 	if (size <= 2)
241 		complete_usage(parser, parser->local.usage_index);
242 
243 	parser->local.usage_size[parser->local.usage_index] = size;
244 	parser->local.collection_index[parser->local.usage_index] =
245 		parser->collection_stack_ptr ?
246 		parser->collection_stack[parser->collection_stack_ptr - 1] : 0;
247 	parser->local.usage_index++;
248 	return 0;
249 }
250 
251 /*
252  * Register a new field for this report.
253  */
254 
255 static int hid_add_field(struct hid_parser *parser, unsigned report_type, unsigned flags)
256 {
257 	struct hid_report *report;
258 	struct hid_field *field;
259 	unsigned int max_buffer_size = HID_MAX_BUFFER_SIZE;
260 	unsigned int usages;
261 	unsigned int offset;
262 	unsigned int i;
263 	unsigned int application;
264 
265 	application = hid_lookup_collection(parser, HID_COLLECTION_APPLICATION);
266 
267 	report = hid_register_report(parser->device, report_type,
268 				     parser->global.report_id, application);
269 	if (!report) {
270 		hid_err(parser->device, "hid_register_report failed\n");
271 		return -1;
272 	}
273 
274 	/* Handle both signed and unsigned cases properly */
275 	if ((parser->global.logical_minimum < 0 &&
276 		parser->global.logical_maximum <
277 		parser->global.logical_minimum) ||
278 		(parser->global.logical_minimum >= 0 &&
279 		(__u32)parser->global.logical_maximum <
280 		(__u32)parser->global.logical_minimum)) {
281 		dbg_hid("logical range invalid 0x%x 0x%x\n",
282 			parser->global.logical_minimum,
283 			parser->global.logical_maximum);
284 		return -1;
285 	}
286 
287 	offset = report->size;
288 	report->size += parser->global.report_size * parser->global.report_count;
289 
290 	if (parser->device->ll_driver->max_buffer_size)
291 		max_buffer_size = parser->device->ll_driver->max_buffer_size;
292 
293 	/* Total size check: Allow for possible report index byte */
294 	if (report->size > (max_buffer_size - 1) << 3) {
295 		hid_err(parser->device, "report is too long\n");
296 		return -1;
297 	}
298 
299 	if (!parser->local.usage_index) /* Ignore padding fields */
300 		return 0;
301 
302 	usages = max_t(unsigned, parser->local.usage_index,
303 				 parser->global.report_count);
304 
305 	field = hid_register_field(report, usages);
306 	if (!field)
307 		return 0;
308 
309 	field->physical = hid_lookup_collection(parser, HID_COLLECTION_PHYSICAL);
310 	field->logical = hid_lookup_collection(parser, HID_COLLECTION_LOGICAL);
311 	field->application = application;
312 
313 	for (i = 0; i < usages; i++) {
314 		unsigned j = i;
315 		/* Duplicate the last usage we parsed if we have excess values */
316 		if (i >= parser->local.usage_index)
317 			j = parser->local.usage_index - 1;
318 		field->usage[i].hid = parser->local.usage[j];
319 		field->usage[i].collection_index =
320 			parser->local.collection_index[j];
321 		field->usage[i].usage_index = i;
322 		field->usage[i].resolution_multiplier = 1;
323 	}
324 
325 	field->maxusage = usages;
326 	field->flags = flags;
327 	field->report_offset = offset;
328 	field->report_type = report_type;
329 	field->report_size = parser->global.report_size;
330 	field->report_count = parser->global.report_count;
331 	field->logical_minimum = parser->global.logical_minimum;
332 	field->logical_maximum = parser->global.logical_maximum;
333 	field->physical_minimum = parser->global.physical_minimum;
334 	field->physical_maximum = parser->global.physical_maximum;
335 	field->unit_exponent = parser->global.unit_exponent;
336 	field->unit = parser->global.unit;
337 
338 	return 0;
339 }
340 
341 /*
342  * Read data value from item.
343  */
344 
345 static u32 item_udata(struct hid_item *item)
346 {
347 	switch (item->size) {
348 	case 1: return item->data.u8;
349 	case 2: return item->data.u16;
350 	case 4: return item->data.u32;
351 	}
352 	return 0;
353 }
354 
355 static s32 item_sdata(struct hid_item *item)
356 {
357 	switch (item->size) {
358 	case 1: return item->data.s8;
359 	case 2: return item->data.s16;
360 	case 4: return item->data.s32;
361 	}
362 	return 0;
363 }
364 
365 /*
366  * Process a global item.
367  */
368 
369 static int hid_parser_global(struct hid_parser *parser, struct hid_item *item)
370 {
371 	__s32 raw_value;
372 	switch (item->tag) {
373 	case HID_GLOBAL_ITEM_TAG_PUSH:
374 
375 		if (parser->global_stack_ptr == HID_GLOBAL_STACK_SIZE) {
376 			hid_err(parser->device, "global environment stack overflow\n");
377 			return -1;
378 		}
379 
380 		memcpy(parser->global_stack + parser->global_stack_ptr++,
381 			&parser->global, sizeof(struct hid_global));
382 		return 0;
383 
384 	case HID_GLOBAL_ITEM_TAG_POP:
385 
386 		if (!parser->global_stack_ptr) {
387 			hid_err(parser->device, "global environment stack underflow\n");
388 			return -1;
389 		}
390 
391 		memcpy(&parser->global, parser->global_stack +
392 			--parser->global_stack_ptr, sizeof(struct hid_global));
393 		return 0;
394 
395 	case HID_GLOBAL_ITEM_TAG_USAGE_PAGE:
396 		parser->global.usage_page = item_udata(item);
397 		return 0;
398 
399 	case HID_GLOBAL_ITEM_TAG_LOGICAL_MINIMUM:
400 		parser->global.logical_minimum = item_sdata(item);
401 		return 0;
402 
403 	case HID_GLOBAL_ITEM_TAG_LOGICAL_MAXIMUM:
404 		if (parser->global.logical_minimum < 0)
405 			parser->global.logical_maximum = item_sdata(item);
406 		else
407 			parser->global.logical_maximum = item_udata(item);
408 		return 0;
409 
410 	case HID_GLOBAL_ITEM_TAG_PHYSICAL_MINIMUM:
411 		parser->global.physical_minimum = item_sdata(item);
412 		return 0;
413 
414 	case HID_GLOBAL_ITEM_TAG_PHYSICAL_MAXIMUM:
415 		if (parser->global.physical_minimum < 0)
416 			parser->global.physical_maximum = item_sdata(item);
417 		else
418 			parser->global.physical_maximum = item_udata(item);
419 		return 0;
420 
421 	case HID_GLOBAL_ITEM_TAG_UNIT_EXPONENT:
422 		/* Many devices provide unit exponent as a two's complement
423 		 * nibble due to the common misunderstanding of HID
424 		 * specification 1.11, 6.2.2.7 Global Items. Attempt to handle
425 		 * both this and the standard encoding. */
426 		raw_value = item_sdata(item);
427 		if (!(raw_value & 0xfffffff0))
428 			parser->global.unit_exponent = hid_snto32(raw_value, 4);
429 		else
430 			parser->global.unit_exponent = raw_value;
431 		return 0;
432 
433 	case HID_GLOBAL_ITEM_TAG_UNIT:
434 		parser->global.unit = item_udata(item);
435 		return 0;
436 
437 	case HID_GLOBAL_ITEM_TAG_REPORT_SIZE:
438 		parser->global.report_size = item_udata(item);
439 		if (parser->global.report_size > 256) {
440 			hid_err(parser->device, "invalid report_size %d\n",
441 					parser->global.report_size);
442 			return -1;
443 		}
444 		return 0;
445 
446 	case HID_GLOBAL_ITEM_TAG_REPORT_COUNT:
447 		parser->global.report_count = item_udata(item);
448 		if (parser->global.report_count > HID_MAX_USAGES) {
449 			hid_err(parser->device, "invalid report_count %d\n",
450 					parser->global.report_count);
451 			return -1;
452 		}
453 		return 0;
454 
455 	case HID_GLOBAL_ITEM_TAG_REPORT_ID:
456 		parser->global.report_id = item_udata(item);
457 		if (parser->global.report_id == 0 ||
458 		    parser->global.report_id >= HID_MAX_IDS) {
459 			hid_err(parser->device, "report_id %u is invalid\n",
460 				parser->global.report_id);
461 			return -1;
462 		}
463 		return 0;
464 
465 	default:
466 		hid_err(parser->device, "unknown global tag 0x%x\n", item->tag);
467 		return -1;
468 	}
469 }
470 
471 /*
472  * Process a local item.
473  */
474 
475 static int hid_parser_local(struct hid_parser *parser, struct hid_item *item)
476 {
477 	__u32 data;
478 	unsigned n;
479 	__u32 count;
480 
481 	data = item_udata(item);
482 
483 	switch (item->tag) {
484 	case HID_LOCAL_ITEM_TAG_DELIMITER:
485 
486 		if (data) {
487 			/*
488 			 * We treat items before the first delimiter
489 			 * as global to all usage sets (branch 0).
490 			 * In the moment we process only these global
491 			 * items and the first delimiter set.
492 			 */
493 			if (parser->local.delimiter_depth != 0) {
494 				hid_err(parser->device, "nested delimiters\n");
495 				return -1;
496 			}
497 			parser->local.delimiter_depth++;
498 			parser->local.delimiter_branch++;
499 		} else {
500 			if (parser->local.delimiter_depth < 1) {
501 				hid_err(parser->device, "bogus close delimiter\n");
502 				return -1;
503 			}
504 			parser->local.delimiter_depth--;
505 		}
506 		return 0;
507 
508 	case HID_LOCAL_ITEM_TAG_USAGE:
509 
510 		if (parser->local.delimiter_branch > 1) {
511 			dbg_hid("alternative usage ignored\n");
512 			return 0;
513 		}
514 
515 		return hid_add_usage(parser, data, item->size);
516 
517 	case HID_LOCAL_ITEM_TAG_USAGE_MINIMUM:
518 
519 		if (parser->local.delimiter_branch > 1) {
520 			dbg_hid("alternative usage ignored\n");
521 			return 0;
522 		}
523 
524 		parser->local.usage_minimum = data;
525 		return 0;
526 
527 	case HID_LOCAL_ITEM_TAG_USAGE_MAXIMUM:
528 
529 		if (parser->local.delimiter_branch > 1) {
530 			dbg_hid("alternative usage ignored\n");
531 			return 0;
532 		}
533 
534 		count = data - parser->local.usage_minimum;
535 		if (count + parser->local.usage_index >= HID_MAX_USAGES) {
536 			/*
537 			 * We do not warn if the name is not set, we are
538 			 * actually pre-scanning the device.
539 			 */
540 			if (dev_name(&parser->device->dev))
541 				hid_warn(parser->device,
542 					 "ignoring exceeding usage max\n");
543 			data = HID_MAX_USAGES - parser->local.usage_index +
544 				parser->local.usage_minimum - 1;
545 			if (data <= 0) {
546 				hid_err(parser->device,
547 					"no more usage index available\n");
548 				return -1;
549 			}
550 		}
551 
552 		for (n = parser->local.usage_minimum; n <= data; n++)
553 			if (hid_add_usage(parser, n, item->size)) {
554 				dbg_hid("hid_add_usage failed\n");
555 				return -1;
556 			}
557 		return 0;
558 
559 	default:
560 
561 		dbg_hid("unknown local item tag 0x%x\n", item->tag);
562 		return 0;
563 	}
564 	return 0;
565 }
566 
567 /*
568  * Concatenate Usage Pages into Usages where relevant:
569  * As per specification, 6.2.2.8: "When the parser encounters a main item it
570  * concatenates the last declared Usage Page with a Usage to form a complete
571  * usage value."
572  */
573 
574 static void hid_concatenate_last_usage_page(struct hid_parser *parser)
575 {
576 	int i;
577 	unsigned int usage_page;
578 	unsigned int current_page;
579 
580 	if (!parser->local.usage_index)
581 		return;
582 
583 	usage_page = parser->global.usage_page;
584 
585 	/*
586 	 * Concatenate usage page again only if last declared Usage Page
587 	 * has not been already used in previous usages concatenation
588 	 */
589 	for (i = parser->local.usage_index - 1; i >= 0; i--) {
590 		if (parser->local.usage_size[i] > 2)
591 			/* Ignore extended usages */
592 			continue;
593 
594 		current_page = parser->local.usage[i] >> 16;
595 		if (current_page == usage_page)
596 			break;
597 
598 		complete_usage(parser, i);
599 	}
600 }
601 
602 /*
603  * Process a main item.
604  */
605 
606 static int hid_parser_main(struct hid_parser *parser, struct hid_item *item)
607 {
608 	__u32 data;
609 	int ret;
610 
611 	hid_concatenate_last_usage_page(parser);
612 
613 	data = item_udata(item);
614 
615 	switch (item->tag) {
616 	case HID_MAIN_ITEM_TAG_BEGIN_COLLECTION:
617 		ret = open_collection(parser, data & 0xff);
618 		break;
619 	case HID_MAIN_ITEM_TAG_END_COLLECTION:
620 		ret = close_collection(parser);
621 		break;
622 	case HID_MAIN_ITEM_TAG_INPUT:
623 		ret = hid_add_field(parser, HID_INPUT_REPORT, data);
624 		break;
625 	case HID_MAIN_ITEM_TAG_OUTPUT:
626 		ret = hid_add_field(parser, HID_OUTPUT_REPORT, data);
627 		break;
628 	case HID_MAIN_ITEM_TAG_FEATURE:
629 		ret = hid_add_field(parser, HID_FEATURE_REPORT, data);
630 		break;
631 	default:
632 		hid_warn(parser->device, "unknown main item tag 0x%x\n", item->tag);
633 		ret = 0;
634 	}
635 
636 	memset(&parser->local, 0, sizeof(parser->local));	/* Reset the local parser environment */
637 
638 	return ret;
639 }
640 
641 /*
642  * Process a reserved item.
643  */
644 
645 static int hid_parser_reserved(struct hid_parser *parser, struct hid_item *item)
646 {
647 	dbg_hid("reserved item type, tag 0x%x\n", item->tag);
648 	return 0;
649 }
650 
651 /*
652  * Free a report and all registered fields. The field->usage and
653  * field->value table's are allocated behind the field, so we need
654  * only to free(field) itself.
655  */
656 
657 static void hid_free_report(struct hid_report *report)
658 {
659 	unsigned n;
660 
661 	kfree(report->field_entries);
662 
663 	for (n = 0; n < report->maxfield; n++)
664 		kvfree(report->field[n]);
665 	kfree(report);
666 }
667 
668 /*
669  * Close report. This function returns the device
670  * state to the point prior to hid_open_report().
671  */
672 static void hid_close_report(struct hid_device *device)
673 {
674 	unsigned i, j;
675 
676 	for (i = 0; i < HID_REPORT_TYPES; i++) {
677 		struct hid_report_enum *report_enum = device->report_enum + i;
678 
679 		for (j = 0; j < HID_MAX_IDS; j++) {
680 			struct hid_report *report = report_enum->report_id_hash[j];
681 			if (report)
682 				hid_free_report(report);
683 		}
684 		memset(report_enum, 0, sizeof(*report_enum));
685 		INIT_LIST_HEAD(&report_enum->report_list);
686 	}
687 
688 	kfree(device->rdesc);
689 	device->rdesc = NULL;
690 	device->rsize = 0;
691 
692 	kfree(device->collection);
693 	device->collection = NULL;
694 	device->collection_size = 0;
695 	device->maxcollection = 0;
696 	device->maxapplication = 0;
697 
698 	device->status &= ~HID_STAT_PARSED;
699 }
700 
701 /*
702  * Free a device structure, all reports, and all fields.
703  */
704 
705 void hiddev_free(struct kref *ref)
706 {
707 	struct hid_device *hid = container_of(ref, struct hid_device, ref);
708 
709 	hid_close_report(hid);
710 	kfree(hid->dev_rdesc);
711 	kfree(hid);
712 }
713 
714 static void hid_device_release(struct device *dev)
715 {
716 	struct hid_device *hid = to_hid_device(dev);
717 
718 	kref_put(&hid->ref, hiddev_free);
719 }
720 
721 /*
722  * Fetch a report description item from the data stream. We support long
723  * items, though they are not used yet.
724  */
725 
726 static u8 *fetch_item(__u8 *start, __u8 *end, struct hid_item *item)
727 {
728 	u8 b;
729 
730 	if ((end - start) <= 0)
731 		return NULL;
732 
733 	b = *start++;
734 
735 	item->type = (b >> 2) & 3;
736 	item->tag  = (b >> 4) & 15;
737 
738 	if (item->tag == HID_ITEM_TAG_LONG) {
739 
740 		item->format = HID_ITEM_FORMAT_LONG;
741 
742 		if ((end - start) < 2)
743 			return NULL;
744 
745 		item->size = *start++;
746 		item->tag  = *start++;
747 
748 		if ((end - start) < item->size)
749 			return NULL;
750 
751 		item->data.longdata = start;
752 		start += item->size;
753 		return start;
754 	}
755 
756 	item->format = HID_ITEM_FORMAT_SHORT;
757 	item->size = b & 3;
758 
759 	switch (item->size) {
760 	case 0:
761 		return start;
762 
763 	case 1:
764 		if ((end - start) < 1)
765 			return NULL;
766 		item->data.u8 = *start++;
767 		return start;
768 
769 	case 2:
770 		if ((end - start) < 2)
771 			return NULL;
772 		item->data.u16 = get_unaligned_le16(start);
773 		start = (__u8 *)((__le16 *)start + 1);
774 		return start;
775 
776 	case 3:
777 		item->size++;
778 		if ((end - start) < 4)
779 			return NULL;
780 		item->data.u32 = get_unaligned_le32(start);
781 		start = (__u8 *)((__le32 *)start + 1);
782 		return start;
783 	}
784 
785 	return NULL;
786 }
787 
788 static void hid_scan_input_usage(struct hid_parser *parser, u32 usage)
789 {
790 	struct hid_device *hid = parser->device;
791 
792 	if (usage == HID_DG_CONTACTID)
793 		hid->group = HID_GROUP_MULTITOUCH;
794 }
795 
796 static void hid_scan_feature_usage(struct hid_parser *parser, u32 usage)
797 {
798 	if (usage == 0xff0000c5 && parser->global.report_count == 256 &&
799 	    parser->global.report_size == 8)
800 		parser->scan_flags |= HID_SCAN_FLAG_MT_WIN_8;
801 
802 	if (usage == 0xff0000c6 && parser->global.report_count == 1 &&
803 	    parser->global.report_size == 8)
804 		parser->scan_flags |= HID_SCAN_FLAG_MT_WIN_8;
805 }
806 
807 static void hid_scan_collection(struct hid_parser *parser, unsigned type)
808 {
809 	struct hid_device *hid = parser->device;
810 	int i;
811 
812 	if (((parser->global.usage_page << 16) == HID_UP_SENSOR) &&
813 	    (type == HID_COLLECTION_PHYSICAL ||
814 	     type == HID_COLLECTION_APPLICATION))
815 		hid->group = HID_GROUP_SENSOR_HUB;
816 
817 	if (hid->vendor == USB_VENDOR_ID_MICROSOFT &&
818 	    hid->product == USB_DEVICE_ID_MS_POWER_COVER &&
819 	    hid->group == HID_GROUP_MULTITOUCH)
820 		hid->group = HID_GROUP_GENERIC;
821 
822 	if ((parser->global.usage_page << 16) == HID_UP_GENDESK)
823 		for (i = 0; i < parser->local.usage_index; i++)
824 			if (parser->local.usage[i] == HID_GD_POINTER)
825 				parser->scan_flags |= HID_SCAN_FLAG_GD_POINTER;
826 
827 	if ((parser->global.usage_page << 16) >= HID_UP_MSVENDOR)
828 		parser->scan_flags |= HID_SCAN_FLAG_VENDOR_SPECIFIC;
829 
830 	if ((parser->global.usage_page << 16) == HID_UP_GOOGLEVENDOR)
831 		for (i = 0; i < parser->local.usage_index; i++)
832 			if (parser->local.usage[i] ==
833 					(HID_UP_GOOGLEVENDOR | 0x0001))
834 				parser->device->group =
835 					HID_GROUP_VIVALDI;
836 }
837 
838 static int hid_scan_main(struct hid_parser *parser, struct hid_item *item)
839 {
840 	__u32 data;
841 	int i;
842 
843 	hid_concatenate_last_usage_page(parser);
844 
845 	data = item_udata(item);
846 
847 	switch (item->tag) {
848 	case HID_MAIN_ITEM_TAG_BEGIN_COLLECTION:
849 		hid_scan_collection(parser, data & 0xff);
850 		break;
851 	case HID_MAIN_ITEM_TAG_END_COLLECTION:
852 		break;
853 	case HID_MAIN_ITEM_TAG_INPUT:
854 		/* ignore constant inputs, they will be ignored by hid-input */
855 		if (data & HID_MAIN_ITEM_CONSTANT)
856 			break;
857 		for (i = 0; i < parser->local.usage_index; i++)
858 			hid_scan_input_usage(parser, parser->local.usage[i]);
859 		break;
860 	case HID_MAIN_ITEM_TAG_OUTPUT:
861 		break;
862 	case HID_MAIN_ITEM_TAG_FEATURE:
863 		for (i = 0; i < parser->local.usage_index; i++)
864 			hid_scan_feature_usage(parser, parser->local.usage[i]);
865 		break;
866 	}
867 
868 	/* Reset the local parser environment */
869 	memset(&parser->local, 0, sizeof(parser->local));
870 
871 	return 0;
872 }
873 
874 /*
875  * Scan a report descriptor before the device is added to the bus.
876  * Sets device groups and other properties that determine what driver
877  * to load.
878  */
879 static int hid_scan_report(struct hid_device *hid)
880 {
881 	struct hid_parser *parser;
882 	struct hid_item item;
883 	__u8 *start = hid->dev_rdesc;
884 	__u8 *end = start + hid->dev_rsize;
885 	static int (*dispatch_type[])(struct hid_parser *parser,
886 				      struct hid_item *item) = {
887 		hid_scan_main,
888 		hid_parser_global,
889 		hid_parser_local,
890 		hid_parser_reserved
891 	};
892 
893 	parser = vzalloc(sizeof(struct hid_parser));
894 	if (!parser)
895 		return -ENOMEM;
896 
897 	parser->device = hid;
898 	hid->group = HID_GROUP_GENERIC;
899 
900 	/*
901 	 * The parsing is simpler than the one in hid_open_report() as we should
902 	 * be robust against hid errors. Those errors will be raised by
903 	 * hid_open_report() anyway.
904 	 */
905 	while ((start = fetch_item(start, end, &item)) != NULL)
906 		dispatch_type[item.type](parser, &item);
907 
908 	/*
909 	 * Handle special flags set during scanning.
910 	 */
911 	if ((parser->scan_flags & HID_SCAN_FLAG_MT_WIN_8) &&
912 	    (hid->group == HID_GROUP_MULTITOUCH))
913 		hid->group = HID_GROUP_MULTITOUCH_WIN_8;
914 
915 	/*
916 	 * Vendor specific handlings
917 	 */
918 	switch (hid->vendor) {
919 	case USB_VENDOR_ID_WACOM:
920 		hid->group = HID_GROUP_WACOM;
921 		break;
922 	case USB_VENDOR_ID_SYNAPTICS:
923 		if (hid->group == HID_GROUP_GENERIC)
924 			if ((parser->scan_flags & HID_SCAN_FLAG_VENDOR_SPECIFIC)
925 			    && (parser->scan_flags & HID_SCAN_FLAG_GD_POINTER))
926 				/*
927 				 * hid-rmi should take care of them,
928 				 * not hid-generic
929 				 */
930 				hid->group = HID_GROUP_RMI;
931 		break;
932 	}
933 
934 	kfree(parser->collection_stack);
935 	vfree(parser);
936 	return 0;
937 }
938 
939 /**
940  * hid_parse_report - parse device report
941  *
942  * @hid: hid device
943  * @start: report start
944  * @size: report size
945  *
946  * Allocate the device report as read by the bus driver. This function should
947  * only be called from parse() in ll drivers.
948  */
949 int hid_parse_report(struct hid_device *hid, __u8 *start, unsigned size)
950 {
951 	hid->dev_rdesc = kmemdup(start, size, GFP_KERNEL);
952 	if (!hid->dev_rdesc)
953 		return -ENOMEM;
954 	hid->dev_rsize = size;
955 	return 0;
956 }
957 EXPORT_SYMBOL_GPL(hid_parse_report);
958 
959 static const char * const hid_report_names[] = {
960 	"HID_INPUT_REPORT",
961 	"HID_OUTPUT_REPORT",
962 	"HID_FEATURE_REPORT",
963 };
964 /**
965  * hid_validate_values - validate existing device report's value indexes
966  *
967  * @hid: hid device
968  * @type: which report type to examine
969  * @id: which report ID to examine (0 for first)
970  * @field_index: which report field to examine
971  * @report_counts: expected number of values
972  *
973  * Validate the number of values in a given field of a given report, after
974  * parsing.
975  */
976 struct hid_report *hid_validate_values(struct hid_device *hid,
977 				       enum hid_report_type type, unsigned int id,
978 				       unsigned int field_index,
979 				       unsigned int report_counts)
980 {
981 	struct hid_report *report;
982 
983 	if (type > HID_FEATURE_REPORT) {
984 		hid_err(hid, "invalid HID report type %u\n", type);
985 		return NULL;
986 	}
987 
988 	if (id >= HID_MAX_IDS) {
989 		hid_err(hid, "invalid HID report id %u\n", id);
990 		return NULL;
991 	}
992 
993 	/*
994 	 * Explicitly not using hid_get_report() here since it depends on
995 	 * ->numbered being checked, which may not always be the case when
996 	 * drivers go to access report values.
997 	 */
998 	if (id == 0) {
999 		/*
1000 		 * Validating on id 0 means we should examine the first
1001 		 * report in the list.
1002 		 */
1003 		report = list_first_entry_or_null(
1004 				&hid->report_enum[type].report_list,
1005 				struct hid_report, list);
1006 	} else {
1007 		report = hid->report_enum[type].report_id_hash[id];
1008 	}
1009 	if (!report) {
1010 		hid_err(hid, "missing %s %u\n", hid_report_names[type], id);
1011 		return NULL;
1012 	}
1013 	if (report->maxfield <= field_index) {
1014 		hid_err(hid, "not enough fields in %s %u\n",
1015 			hid_report_names[type], id);
1016 		return NULL;
1017 	}
1018 	if (report->field[field_index]->report_count < report_counts) {
1019 		hid_err(hid, "not enough values in %s %u field %u\n",
1020 			hid_report_names[type], id, field_index);
1021 		return NULL;
1022 	}
1023 	return report;
1024 }
1025 EXPORT_SYMBOL_GPL(hid_validate_values);
1026 
1027 static int hid_calculate_multiplier(struct hid_device *hid,
1028 				     struct hid_field *multiplier)
1029 {
1030 	int m;
1031 	__s32 v = *multiplier->value;
1032 	__s32 lmin = multiplier->logical_minimum;
1033 	__s32 lmax = multiplier->logical_maximum;
1034 	__s32 pmin = multiplier->physical_minimum;
1035 	__s32 pmax = multiplier->physical_maximum;
1036 
1037 	/*
1038 	 * "Because OS implementations will generally divide the control's
1039 	 * reported count by the Effective Resolution Multiplier, designers
1040 	 * should take care not to establish a potential Effective
1041 	 * Resolution Multiplier of zero."
1042 	 * HID Usage Table, v1.12, Section 4.3.1, p31
1043 	 */
1044 	if (lmax - lmin == 0)
1045 		return 1;
1046 	/*
1047 	 * Handling the unit exponent is left as an exercise to whoever
1048 	 * finds a device where that exponent is not 0.
1049 	 */
1050 	m = ((v - lmin)/(lmax - lmin) * (pmax - pmin) + pmin);
1051 	if (unlikely(multiplier->unit_exponent != 0)) {
1052 		hid_warn(hid,
1053 			 "unsupported Resolution Multiplier unit exponent %d\n",
1054 			 multiplier->unit_exponent);
1055 	}
1056 
1057 	/* There are no devices with an effective multiplier > 255 */
1058 	if (unlikely(m == 0 || m > 255 || m < -255)) {
1059 		hid_warn(hid, "unsupported Resolution Multiplier %d\n", m);
1060 		m = 1;
1061 	}
1062 
1063 	return m;
1064 }
1065 
1066 static void hid_apply_multiplier_to_field(struct hid_device *hid,
1067 					  struct hid_field *field,
1068 					  struct hid_collection *multiplier_collection,
1069 					  int effective_multiplier)
1070 {
1071 	struct hid_collection *collection;
1072 	struct hid_usage *usage;
1073 	int i;
1074 
1075 	/*
1076 	 * If multiplier_collection is NULL, the multiplier applies
1077 	 * to all fields in the report.
1078 	 * Otherwise, it is the Logical Collection the multiplier applies to
1079 	 * but our field may be in a subcollection of that collection.
1080 	 */
1081 	for (i = 0; i < field->maxusage; i++) {
1082 		usage = &field->usage[i];
1083 
1084 		collection = &hid->collection[usage->collection_index];
1085 		while (collection->parent_idx != -1 &&
1086 		       collection != multiplier_collection)
1087 			collection = &hid->collection[collection->parent_idx];
1088 
1089 		if (collection->parent_idx != -1 ||
1090 		    multiplier_collection == NULL)
1091 			usage->resolution_multiplier = effective_multiplier;
1092 
1093 	}
1094 }
1095 
1096 static void hid_apply_multiplier(struct hid_device *hid,
1097 				 struct hid_field *multiplier)
1098 {
1099 	struct hid_report_enum *rep_enum;
1100 	struct hid_report *rep;
1101 	struct hid_field *field;
1102 	struct hid_collection *multiplier_collection;
1103 	int effective_multiplier;
1104 	int i;
1105 
1106 	/*
1107 	 * "The Resolution Multiplier control must be contained in the same
1108 	 * Logical Collection as the control(s) to which it is to be applied.
1109 	 * If no Resolution Multiplier is defined, then the Resolution
1110 	 * Multiplier defaults to 1.  If more than one control exists in a
1111 	 * Logical Collection, the Resolution Multiplier is associated with
1112 	 * all controls in the collection. If no Logical Collection is
1113 	 * defined, the Resolution Multiplier is associated with all
1114 	 * controls in the report."
1115 	 * HID Usage Table, v1.12, Section 4.3.1, p30
1116 	 *
1117 	 * Thus, search from the current collection upwards until we find a
1118 	 * logical collection. Then search all fields for that same parent
1119 	 * collection. Those are the fields the multiplier applies to.
1120 	 *
1121 	 * If we have more than one multiplier, it will overwrite the
1122 	 * applicable fields later.
1123 	 */
1124 	multiplier_collection = &hid->collection[multiplier->usage->collection_index];
1125 	while (multiplier_collection->parent_idx != -1 &&
1126 	       multiplier_collection->type != HID_COLLECTION_LOGICAL)
1127 		multiplier_collection = &hid->collection[multiplier_collection->parent_idx];
1128 
1129 	effective_multiplier = hid_calculate_multiplier(hid, multiplier);
1130 
1131 	rep_enum = &hid->report_enum[HID_INPUT_REPORT];
1132 	list_for_each_entry(rep, &rep_enum->report_list, list) {
1133 		for (i = 0; i < rep->maxfield; i++) {
1134 			field = rep->field[i];
1135 			hid_apply_multiplier_to_field(hid, field,
1136 						      multiplier_collection,
1137 						      effective_multiplier);
1138 		}
1139 	}
1140 }
1141 
1142 /*
1143  * hid_setup_resolution_multiplier - set up all resolution multipliers
1144  *
1145  * @device: hid device
1146  *
1147  * Search for all Resolution Multiplier Feature Reports and apply their
1148  * value to all matching Input items. This only updates the internal struct
1149  * fields.
1150  *
1151  * The Resolution Multiplier is applied by the hardware. If the multiplier
1152  * is anything other than 1, the hardware will send pre-multiplied events
1153  * so that the same physical interaction generates an accumulated
1154  *	accumulated_value = value * * multiplier
1155  * This may be achieved by sending
1156  * - "value * multiplier" for each event, or
1157  * - "value" but "multiplier" times as frequently, or
1158  * - a combination of the above
1159  * The only guarantee is that the same physical interaction always generates
1160  * an accumulated 'value * multiplier'.
1161  *
1162  * This function must be called before any event processing and after
1163  * any SetRequest to the Resolution Multiplier.
1164  */
1165 void hid_setup_resolution_multiplier(struct hid_device *hid)
1166 {
1167 	struct hid_report_enum *rep_enum;
1168 	struct hid_report *rep;
1169 	struct hid_usage *usage;
1170 	int i, j;
1171 
1172 	rep_enum = &hid->report_enum[HID_FEATURE_REPORT];
1173 	list_for_each_entry(rep, &rep_enum->report_list, list) {
1174 		for (i = 0; i < rep->maxfield; i++) {
1175 			/* Ignore if report count is out of bounds. */
1176 			if (rep->field[i]->report_count < 1)
1177 				continue;
1178 
1179 			for (j = 0; j < rep->field[i]->maxusage; j++) {
1180 				usage = &rep->field[i]->usage[j];
1181 				if (usage->hid == HID_GD_RESOLUTION_MULTIPLIER)
1182 					hid_apply_multiplier(hid,
1183 							     rep->field[i]);
1184 			}
1185 		}
1186 	}
1187 }
1188 EXPORT_SYMBOL_GPL(hid_setup_resolution_multiplier);
1189 
1190 /**
1191  * hid_open_report - open a driver-specific device report
1192  *
1193  * @device: hid device
1194  *
1195  * Parse a report description into a hid_device structure. Reports are
1196  * enumerated, fields are attached to these reports.
1197  * 0 returned on success, otherwise nonzero error value.
1198  *
1199  * This function (or the equivalent hid_parse() macro) should only be
1200  * called from probe() in drivers, before starting the device.
1201  */
1202 int hid_open_report(struct hid_device *device)
1203 {
1204 	struct hid_parser *parser;
1205 	struct hid_item item;
1206 	unsigned int size;
1207 	__u8 *start;
1208 	__u8 *buf;
1209 	__u8 *end;
1210 	__u8 *next;
1211 	int ret;
1212 	int i;
1213 	static int (*dispatch_type[])(struct hid_parser *parser,
1214 				      struct hid_item *item) = {
1215 		hid_parser_main,
1216 		hid_parser_global,
1217 		hid_parser_local,
1218 		hid_parser_reserved
1219 	};
1220 
1221 	if (WARN_ON(device->status & HID_STAT_PARSED))
1222 		return -EBUSY;
1223 
1224 	start = device->dev_rdesc;
1225 	if (WARN_ON(!start))
1226 		return -ENODEV;
1227 	size = device->dev_rsize;
1228 
1229 	/* call_hid_bpf_rdesc_fixup() ensures we work on a copy of rdesc */
1230 	buf = call_hid_bpf_rdesc_fixup(device, start, &size);
1231 	if (buf == NULL)
1232 		return -ENOMEM;
1233 
1234 	if (device->driver->report_fixup)
1235 		start = device->driver->report_fixup(device, buf, &size);
1236 	else
1237 		start = buf;
1238 
1239 	start = kmemdup(start, size, GFP_KERNEL);
1240 	kfree(buf);
1241 	if (start == NULL)
1242 		return -ENOMEM;
1243 
1244 	device->rdesc = start;
1245 	device->rsize = size;
1246 
1247 	parser = vzalloc(sizeof(struct hid_parser));
1248 	if (!parser) {
1249 		ret = -ENOMEM;
1250 		goto alloc_err;
1251 	}
1252 
1253 	parser->device = device;
1254 
1255 	end = start + size;
1256 
1257 	device->collection = kcalloc(HID_DEFAULT_NUM_COLLECTIONS,
1258 				     sizeof(struct hid_collection), GFP_KERNEL);
1259 	if (!device->collection) {
1260 		ret = -ENOMEM;
1261 		goto err;
1262 	}
1263 	device->collection_size = HID_DEFAULT_NUM_COLLECTIONS;
1264 	for (i = 0; i < HID_DEFAULT_NUM_COLLECTIONS; i++)
1265 		device->collection[i].parent_idx = -1;
1266 
1267 	ret = -EINVAL;
1268 	while ((next = fetch_item(start, end, &item)) != NULL) {
1269 		start = next;
1270 
1271 		if (item.format != HID_ITEM_FORMAT_SHORT) {
1272 			hid_err(device, "unexpected long global item\n");
1273 			goto err;
1274 		}
1275 
1276 		if (dispatch_type[item.type](parser, &item)) {
1277 			hid_err(device, "item %u %u %u %u parsing failed\n",
1278 				item.format, (unsigned)item.size,
1279 				(unsigned)item.type, (unsigned)item.tag);
1280 			goto err;
1281 		}
1282 
1283 		if (start == end) {
1284 			if (parser->collection_stack_ptr) {
1285 				hid_err(device, "unbalanced collection at end of report description\n");
1286 				goto err;
1287 			}
1288 			if (parser->local.delimiter_depth) {
1289 				hid_err(device, "unbalanced delimiter at end of report description\n");
1290 				goto err;
1291 			}
1292 
1293 			/*
1294 			 * fetch initial values in case the device's
1295 			 * default multiplier isn't the recommended 1
1296 			 */
1297 			hid_setup_resolution_multiplier(device);
1298 
1299 			kfree(parser->collection_stack);
1300 			vfree(parser);
1301 			device->status |= HID_STAT_PARSED;
1302 
1303 			return 0;
1304 		}
1305 	}
1306 
1307 	hid_err(device, "item fetching failed at offset %u/%u\n",
1308 		size - (unsigned int)(end - start), size);
1309 err:
1310 	kfree(parser->collection_stack);
1311 alloc_err:
1312 	vfree(parser);
1313 	hid_close_report(device);
1314 	return ret;
1315 }
1316 EXPORT_SYMBOL_GPL(hid_open_report);
1317 
1318 /*
1319  * Convert a signed n-bit integer to signed 32-bit integer. Common
1320  * cases are done through the compiler, the screwed things has to be
1321  * done by hand.
1322  */
1323 
1324 static s32 snto32(__u32 value, unsigned n)
1325 {
1326 	if (!value || !n)
1327 		return 0;
1328 
1329 	if (n > 32)
1330 		n = 32;
1331 
1332 	switch (n) {
1333 	case 8:  return ((__s8)value);
1334 	case 16: return ((__s16)value);
1335 	case 32: return ((__s32)value);
1336 	}
1337 	return value & (1 << (n - 1)) ? value | (~0U << n) : value;
1338 }
1339 
1340 s32 hid_snto32(__u32 value, unsigned n)
1341 {
1342 	return snto32(value, n);
1343 }
1344 EXPORT_SYMBOL_GPL(hid_snto32);
1345 
1346 /*
1347  * Convert a signed 32-bit integer to a signed n-bit integer.
1348  */
1349 
1350 static u32 s32ton(__s32 value, unsigned n)
1351 {
1352 	s32 a = value >> (n - 1);
1353 	if (a && a != -1)
1354 		return value < 0 ? 1 << (n - 1) : (1 << (n - 1)) - 1;
1355 	return value & ((1 << n) - 1);
1356 }
1357 
1358 /*
1359  * Extract/implement a data field from/to a little endian report (bit array).
1360  *
1361  * Code sort-of follows HID spec:
1362  *     http://www.usb.org/developers/hidpage/HID1_11.pdf
1363  *
1364  * While the USB HID spec allows unlimited length bit fields in "report
1365  * descriptors", most devices never use more than 16 bits.
1366  * One model of UPS is claimed to report "LINEV" as a 32-bit field.
1367  * Search linux-kernel and linux-usb-devel archives for "hid-core extract".
1368  */
1369 
1370 static u32 __extract(u8 *report, unsigned offset, int n)
1371 {
1372 	unsigned int idx = offset / 8;
1373 	unsigned int bit_nr = 0;
1374 	unsigned int bit_shift = offset % 8;
1375 	int bits_to_copy = 8 - bit_shift;
1376 	u32 value = 0;
1377 	u32 mask = n < 32 ? (1U << n) - 1 : ~0U;
1378 
1379 	while (n > 0) {
1380 		value |= ((u32)report[idx] >> bit_shift) << bit_nr;
1381 		n -= bits_to_copy;
1382 		bit_nr += bits_to_copy;
1383 		bits_to_copy = 8;
1384 		bit_shift = 0;
1385 		idx++;
1386 	}
1387 
1388 	return value & mask;
1389 }
1390 
1391 u32 hid_field_extract(const struct hid_device *hid, u8 *report,
1392 			unsigned offset, unsigned n)
1393 {
1394 	if (n > 32) {
1395 		hid_warn_once(hid, "%s() called with n (%d) > 32! (%s)\n",
1396 			      __func__, n, current->comm);
1397 		n = 32;
1398 	}
1399 
1400 	return __extract(report, offset, n);
1401 }
1402 EXPORT_SYMBOL_GPL(hid_field_extract);
1403 
1404 /*
1405  * "implement" : set bits in a little endian bit stream.
1406  * Same concepts as "extract" (see comments above).
1407  * The data mangled in the bit stream remains in little endian
1408  * order the whole time. It make more sense to talk about
1409  * endianness of register values by considering a register
1410  * a "cached" copy of the little endian bit stream.
1411  */
1412 
1413 static void __implement(u8 *report, unsigned offset, int n, u32 value)
1414 {
1415 	unsigned int idx = offset / 8;
1416 	unsigned int bit_shift = offset % 8;
1417 	int bits_to_set = 8 - bit_shift;
1418 
1419 	while (n - bits_to_set >= 0) {
1420 		report[idx] &= ~(0xff << bit_shift);
1421 		report[idx] |= value << bit_shift;
1422 		value >>= bits_to_set;
1423 		n -= bits_to_set;
1424 		bits_to_set = 8;
1425 		bit_shift = 0;
1426 		idx++;
1427 	}
1428 
1429 	/* last nibble */
1430 	if (n) {
1431 		u8 bit_mask = ((1U << n) - 1);
1432 		report[idx] &= ~(bit_mask << bit_shift);
1433 		report[idx] |= value << bit_shift;
1434 	}
1435 }
1436 
1437 static void implement(const struct hid_device *hid, u8 *report,
1438 		      unsigned offset, unsigned n, u32 value)
1439 {
1440 	if (unlikely(n > 32)) {
1441 		hid_warn(hid, "%s() called with n (%d) > 32! (%s)\n",
1442 			 __func__, n, current->comm);
1443 		n = 32;
1444 	} else if (n < 32) {
1445 		u32 m = (1U << n) - 1;
1446 
1447 		if (unlikely(value > m)) {
1448 			hid_warn(hid,
1449 				 "%s() called with too large value %d (n: %d)! (%s)\n",
1450 				 __func__, value, n, current->comm);
1451 			value &= m;
1452 		}
1453 	}
1454 
1455 	__implement(report, offset, n, value);
1456 }
1457 
1458 /*
1459  * Search an array for a value.
1460  */
1461 
1462 static int search(__s32 *array, __s32 value, unsigned n)
1463 {
1464 	while (n--) {
1465 		if (*array++ == value)
1466 			return 0;
1467 	}
1468 	return -1;
1469 }
1470 
1471 /**
1472  * hid_match_report - check if driver's raw_event should be called
1473  *
1474  * @hid: hid device
1475  * @report: hid report to match against
1476  *
1477  * compare hid->driver->report_table->report_type to report->type
1478  */
1479 static int hid_match_report(struct hid_device *hid, struct hid_report *report)
1480 {
1481 	const struct hid_report_id *id = hid->driver->report_table;
1482 
1483 	if (!id) /* NULL means all */
1484 		return 1;
1485 
1486 	for (; id->report_type != HID_TERMINATOR; id++)
1487 		if (id->report_type == HID_ANY_ID ||
1488 				id->report_type == report->type)
1489 			return 1;
1490 	return 0;
1491 }
1492 
1493 /**
1494  * hid_match_usage - check if driver's event should be called
1495  *
1496  * @hid: hid device
1497  * @usage: usage to match against
1498  *
1499  * compare hid->driver->usage_table->usage_{type,code} to
1500  * usage->usage_{type,code}
1501  */
1502 static int hid_match_usage(struct hid_device *hid, struct hid_usage *usage)
1503 {
1504 	const struct hid_usage_id *id = hid->driver->usage_table;
1505 
1506 	if (!id) /* NULL means all */
1507 		return 1;
1508 
1509 	for (; id->usage_type != HID_ANY_ID - 1; id++)
1510 		if ((id->usage_hid == HID_ANY_ID ||
1511 				id->usage_hid == usage->hid) &&
1512 				(id->usage_type == HID_ANY_ID ||
1513 				id->usage_type == usage->type) &&
1514 				(id->usage_code == HID_ANY_ID ||
1515 				 id->usage_code == usage->code))
1516 			return 1;
1517 	return 0;
1518 }
1519 
1520 static void hid_process_event(struct hid_device *hid, struct hid_field *field,
1521 		struct hid_usage *usage, __s32 value, int interrupt)
1522 {
1523 	struct hid_driver *hdrv = hid->driver;
1524 	int ret;
1525 
1526 	if (!list_empty(&hid->debug_list))
1527 		hid_dump_input(hid, usage, value);
1528 
1529 	if (hdrv && hdrv->event && hid_match_usage(hid, usage)) {
1530 		ret = hdrv->event(hid, field, usage, value);
1531 		if (ret != 0) {
1532 			if (ret < 0)
1533 				hid_err(hid, "%s's event failed with %d\n",
1534 						hdrv->name, ret);
1535 			return;
1536 		}
1537 	}
1538 
1539 	if (hid->claimed & HID_CLAIMED_INPUT)
1540 		hidinput_hid_event(hid, field, usage, value);
1541 	if (hid->claimed & HID_CLAIMED_HIDDEV && interrupt && hid->hiddev_hid_event)
1542 		hid->hiddev_hid_event(hid, field, usage, value);
1543 }
1544 
1545 /*
1546  * Checks if the given value is valid within this field
1547  */
1548 static inline int hid_array_value_is_valid(struct hid_field *field,
1549 					   __s32 value)
1550 {
1551 	__s32 min = field->logical_minimum;
1552 
1553 	/*
1554 	 * Value needs to be between logical min and max, and
1555 	 * (value - min) is used as an index in the usage array.
1556 	 * This array is of size field->maxusage
1557 	 */
1558 	return value >= min &&
1559 	       value <= field->logical_maximum &&
1560 	       value - min < field->maxusage;
1561 }
1562 
1563 /*
1564  * Fetch the field from the data. The field content is stored for next
1565  * report processing (we do differential reporting to the layer).
1566  */
1567 static void hid_input_fetch_field(struct hid_device *hid,
1568 				  struct hid_field *field,
1569 				  __u8 *data)
1570 {
1571 	unsigned n;
1572 	unsigned count = field->report_count;
1573 	unsigned offset = field->report_offset;
1574 	unsigned size = field->report_size;
1575 	__s32 min = field->logical_minimum;
1576 	__s32 *value;
1577 
1578 	value = field->new_value;
1579 	memset(value, 0, count * sizeof(__s32));
1580 	field->ignored = false;
1581 
1582 	for (n = 0; n < count; n++) {
1583 
1584 		value[n] = min < 0 ?
1585 			snto32(hid_field_extract(hid, data, offset + n * size,
1586 			       size), size) :
1587 			hid_field_extract(hid, data, offset + n * size, size);
1588 
1589 		/* Ignore report if ErrorRollOver */
1590 		if (!(field->flags & HID_MAIN_ITEM_VARIABLE) &&
1591 		    hid_array_value_is_valid(field, value[n]) &&
1592 		    field->usage[value[n] - min].hid == HID_UP_KEYBOARD + 1) {
1593 			field->ignored = true;
1594 			return;
1595 		}
1596 	}
1597 }
1598 
1599 /*
1600  * Process a received variable field.
1601  */
1602 
1603 static void hid_input_var_field(struct hid_device *hid,
1604 				struct hid_field *field,
1605 				int interrupt)
1606 {
1607 	unsigned int count = field->report_count;
1608 	__s32 *value = field->new_value;
1609 	unsigned int n;
1610 
1611 	for (n = 0; n < count; n++)
1612 		hid_process_event(hid,
1613 				  field,
1614 				  &field->usage[n],
1615 				  value[n],
1616 				  interrupt);
1617 
1618 	memcpy(field->value, value, count * sizeof(__s32));
1619 }
1620 
1621 /*
1622  * Process a received array field. The field content is stored for
1623  * next report processing (we do differential reporting to the layer).
1624  */
1625 
1626 static void hid_input_array_field(struct hid_device *hid,
1627 				  struct hid_field *field,
1628 				  int interrupt)
1629 {
1630 	unsigned int n;
1631 	unsigned int count = field->report_count;
1632 	__s32 min = field->logical_minimum;
1633 	__s32 *value;
1634 
1635 	value = field->new_value;
1636 
1637 	/* ErrorRollOver */
1638 	if (field->ignored)
1639 		return;
1640 
1641 	for (n = 0; n < count; n++) {
1642 		if (hid_array_value_is_valid(field, field->value[n]) &&
1643 		    search(value, field->value[n], count))
1644 			hid_process_event(hid,
1645 					  field,
1646 					  &field->usage[field->value[n] - min],
1647 					  0,
1648 					  interrupt);
1649 
1650 		if (hid_array_value_is_valid(field, value[n]) &&
1651 		    search(field->value, value[n], count))
1652 			hid_process_event(hid,
1653 					  field,
1654 					  &field->usage[value[n] - min],
1655 					  1,
1656 					  interrupt);
1657 	}
1658 
1659 	memcpy(field->value, value, count * sizeof(__s32));
1660 }
1661 
1662 /*
1663  * Analyse a received report, and fetch the data from it. The field
1664  * content is stored for next report processing (we do differential
1665  * reporting to the layer).
1666  */
1667 static void hid_process_report(struct hid_device *hid,
1668 			       struct hid_report *report,
1669 			       __u8 *data,
1670 			       int interrupt)
1671 {
1672 	unsigned int a;
1673 	struct hid_field_entry *entry;
1674 	struct hid_field *field;
1675 
1676 	/* first retrieve all incoming values in data */
1677 	for (a = 0; a < report->maxfield; a++)
1678 		hid_input_fetch_field(hid, report->field[a], data);
1679 
1680 	if (!list_empty(&report->field_entry_list)) {
1681 		/* INPUT_REPORT, we have a priority list of fields */
1682 		list_for_each_entry(entry,
1683 				    &report->field_entry_list,
1684 				    list) {
1685 			field = entry->field;
1686 
1687 			if (field->flags & HID_MAIN_ITEM_VARIABLE)
1688 				hid_process_event(hid,
1689 						  field,
1690 						  &field->usage[entry->index],
1691 						  field->new_value[entry->index],
1692 						  interrupt);
1693 			else
1694 				hid_input_array_field(hid, field, interrupt);
1695 		}
1696 
1697 		/* we need to do the memcpy at the end for var items */
1698 		for (a = 0; a < report->maxfield; a++) {
1699 			field = report->field[a];
1700 
1701 			if (field->flags & HID_MAIN_ITEM_VARIABLE)
1702 				memcpy(field->value, field->new_value,
1703 				       field->report_count * sizeof(__s32));
1704 		}
1705 	} else {
1706 		/* FEATURE_REPORT, regular processing */
1707 		for (a = 0; a < report->maxfield; a++) {
1708 			field = report->field[a];
1709 
1710 			if (field->flags & HID_MAIN_ITEM_VARIABLE)
1711 				hid_input_var_field(hid, field, interrupt);
1712 			else
1713 				hid_input_array_field(hid, field, interrupt);
1714 		}
1715 	}
1716 }
1717 
1718 /*
1719  * Insert a given usage_index in a field in the list
1720  * of processed usages in the report.
1721  *
1722  * The elements of lower priority score are processed
1723  * first.
1724  */
1725 static void __hid_insert_field_entry(struct hid_device *hid,
1726 				     struct hid_report *report,
1727 				     struct hid_field_entry *entry,
1728 				     struct hid_field *field,
1729 				     unsigned int usage_index)
1730 {
1731 	struct hid_field_entry *next;
1732 
1733 	entry->field = field;
1734 	entry->index = usage_index;
1735 	entry->priority = field->usages_priorities[usage_index];
1736 
1737 	/* insert the element at the correct position */
1738 	list_for_each_entry(next,
1739 			    &report->field_entry_list,
1740 			    list) {
1741 		/*
1742 		 * the priority of our element is strictly higher
1743 		 * than the next one, insert it before
1744 		 */
1745 		if (entry->priority > next->priority) {
1746 			list_add_tail(&entry->list, &next->list);
1747 			return;
1748 		}
1749 	}
1750 
1751 	/* lowest priority score: insert at the end */
1752 	list_add_tail(&entry->list, &report->field_entry_list);
1753 }
1754 
1755 static void hid_report_process_ordering(struct hid_device *hid,
1756 					struct hid_report *report)
1757 {
1758 	struct hid_field *field;
1759 	struct hid_field_entry *entries;
1760 	unsigned int a, u, usages;
1761 	unsigned int count = 0;
1762 
1763 	/* count the number of individual fields in the report */
1764 	for (a = 0; a < report->maxfield; a++) {
1765 		field = report->field[a];
1766 
1767 		if (field->flags & HID_MAIN_ITEM_VARIABLE)
1768 			count += field->report_count;
1769 		else
1770 			count++;
1771 	}
1772 
1773 	/* allocate the memory to process the fields */
1774 	entries = kcalloc(count, sizeof(*entries), GFP_KERNEL);
1775 	if (!entries)
1776 		return;
1777 
1778 	report->field_entries = entries;
1779 
1780 	/*
1781 	 * walk through all fields in the report and
1782 	 * store them by priority order in report->field_entry_list
1783 	 *
1784 	 * - Var elements are individualized (field + usage_index)
1785 	 * - Arrays are taken as one, we can not chose an order for them
1786 	 */
1787 	usages = 0;
1788 	for (a = 0; a < report->maxfield; a++) {
1789 		field = report->field[a];
1790 
1791 		if (field->flags & HID_MAIN_ITEM_VARIABLE) {
1792 			for (u = 0; u < field->report_count; u++) {
1793 				__hid_insert_field_entry(hid, report,
1794 							 &entries[usages],
1795 							 field, u);
1796 				usages++;
1797 			}
1798 		} else {
1799 			__hid_insert_field_entry(hid, report, &entries[usages],
1800 						 field, 0);
1801 			usages++;
1802 		}
1803 	}
1804 }
1805 
1806 static void hid_process_ordering(struct hid_device *hid)
1807 {
1808 	struct hid_report *report;
1809 	struct hid_report_enum *report_enum = &hid->report_enum[HID_INPUT_REPORT];
1810 
1811 	list_for_each_entry(report, &report_enum->report_list, list)
1812 		hid_report_process_ordering(hid, report);
1813 }
1814 
1815 /*
1816  * Output the field into the report.
1817  */
1818 
1819 static void hid_output_field(const struct hid_device *hid,
1820 			     struct hid_field *field, __u8 *data)
1821 {
1822 	unsigned count = field->report_count;
1823 	unsigned offset = field->report_offset;
1824 	unsigned size = field->report_size;
1825 	unsigned n;
1826 
1827 	for (n = 0; n < count; n++) {
1828 		if (field->logical_minimum < 0)	/* signed values */
1829 			implement(hid, data, offset + n * size, size,
1830 				  s32ton(field->value[n], size));
1831 		else				/* unsigned values */
1832 			implement(hid, data, offset + n * size, size,
1833 				  field->value[n]);
1834 	}
1835 }
1836 
1837 /*
1838  * Compute the size of a report.
1839  */
1840 static size_t hid_compute_report_size(struct hid_report *report)
1841 {
1842 	if (report->size)
1843 		return ((report->size - 1) >> 3) + 1;
1844 
1845 	return 0;
1846 }
1847 
1848 /*
1849  * Create a report. 'data' has to be allocated using
1850  * hid_alloc_report_buf() so that it has proper size.
1851  */
1852 
1853 void hid_output_report(struct hid_report *report, __u8 *data)
1854 {
1855 	unsigned n;
1856 
1857 	if (report->id > 0)
1858 		*data++ = report->id;
1859 
1860 	memset(data, 0, hid_compute_report_size(report));
1861 	for (n = 0; n < report->maxfield; n++)
1862 		hid_output_field(report->device, report->field[n], data);
1863 }
1864 EXPORT_SYMBOL_GPL(hid_output_report);
1865 
1866 /*
1867  * Allocator for buffer that is going to be passed to hid_output_report()
1868  */
1869 u8 *hid_alloc_report_buf(struct hid_report *report, gfp_t flags)
1870 {
1871 	/*
1872 	 * 7 extra bytes are necessary to achieve proper functionality
1873 	 * of implement() working on 8 byte chunks
1874 	 */
1875 
1876 	u32 len = hid_report_len(report) + 7;
1877 
1878 	return kmalloc(len, flags);
1879 }
1880 EXPORT_SYMBOL_GPL(hid_alloc_report_buf);
1881 
1882 /*
1883  * Set a field value. The report this field belongs to has to be
1884  * created and transferred to the device, to set this value in the
1885  * device.
1886  */
1887 
1888 int hid_set_field(struct hid_field *field, unsigned offset, __s32 value)
1889 {
1890 	unsigned size;
1891 
1892 	if (!field)
1893 		return -1;
1894 
1895 	size = field->report_size;
1896 
1897 	hid_dump_input(field->report->device, field->usage + offset, value);
1898 
1899 	if (offset >= field->report_count) {
1900 		hid_err(field->report->device, "offset (%d) exceeds report_count (%d)\n",
1901 				offset, field->report_count);
1902 		return -1;
1903 	}
1904 	if (field->logical_minimum < 0) {
1905 		if (value != snto32(s32ton(value, size), size)) {
1906 			hid_err(field->report->device, "value %d is out of range\n", value);
1907 			return -1;
1908 		}
1909 	}
1910 	field->value[offset] = value;
1911 	return 0;
1912 }
1913 EXPORT_SYMBOL_GPL(hid_set_field);
1914 
1915 static struct hid_report *hid_get_report(struct hid_report_enum *report_enum,
1916 		const u8 *data)
1917 {
1918 	struct hid_report *report;
1919 	unsigned int n = 0;	/* Normally report number is 0 */
1920 
1921 	/* Device uses numbered reports, data[0] is report number */
1922 	if (report_enum->numbered)
1923 		n = *data;
1924 
1925 	report = report_enum->report_id_hash[n];
1926 	if (report == NULL)
1927 		dbg_hid("undefined report_id %u received\n", n);
1928 
1929 	return report;
1930 }
1931 
1932 /*
1933  * Implement a generic .request() callback, using .raw_request()
1934  * DO NOT USE in hid drivers directly, but through hid_hw_request instead.
1935  */
1936 int __hid_request(struct hid_device *hid, struct hid_report *report,
1937 		enum hid_class_request reqtype)
1938 {
1939 	char *buf;
1940 	int ret;
1941 	u32 len;
1942 
1943 	buf = hid_alloc_report_buf(report, GFP_KERNEL);
1944 	if (!buf)
1945 		return -ENOMEM;
1946 
1947 	len = hid_report_len(report);
1948 
1949 	if (reqtype == HID_REQ_SET_REPORT)
1950 		hid_output_report(report, buf);
1951 
1952 	ret = hid->ll_driver->raw_request(hid, report->id, buf, len,
1953 					  report->type, reqtype);
1954 	if (ret < 0) {
1955 		dbg_hid("unable to complete request: %d\n", ret);
1956 		goto out;
1957 	}
1958 
1959 	if (reqtype == HID_REQ_GET_REPORT)
1960 		hid_input_report(hid, report->type, buf, ret, 0);
1961 
1962 	ret = 0;
1963 
1964 out:
1965 	kfree(buf);
1966 	return ret;
1967 }
1968 EXPORT_SYMBOL_GPL(__hid_request);
1969 
1970 int hid_report_raw_event(struct hid_device *hid, enum hid_report_type type, u8 *data, u32 size,
1971 			 int interrupt)
1972 {
1973 	struct hid_report_enum *report_enum = hid->report_enum + type;
1974 	struct hid_report *report;
1975 	struct hid_driver *hdrv;
1976 	int max_buffer_size = HID_MAX_BUFFER_SIZE;
1977 	u32 rsize, csize = size;
1978 	u8 *cdata = data;
1979 	int ret = 0;
1980 
1981 	report = hid_get_report(report_enum, data);
1982 	if (!report)
1983 		goto out;
1984 
1985 	if (report_enum->numbered) {
1986 		cdata++;
1987 		csize--;
1988 	}
1989 
1990 	rsize = hid_compute_report_size(report);
1991 
1992 	if (hid->ll_driver->max_buffer_size)
1993 		max_buffer_size = hid->ll_driver->max_buffer_size;
1994 
1995 	if (report_enum->numbered && rsize >= max_buffer_size)
1996 		rsize = max_buffer_size - 1;
1997 	else if (rsize > max_buffer_size)
1998 		rsize = max_buffer_size;
1999 
2000 	if (csize < rsize) {
2001 		dbg_hid("report %d is too short, (%d < %d)\n", report->id,
2002 				csize, rsize);
2003 		memset(cdata + csize, 0, rsize - csize);
2004 	}
2005 
2006 	if ((hid->claimed & HID_CLAIMED_HIDDEV) && hid->hiddev_report_event)
2007 		hid->hiddev_report_event(hid, report);
2008 	if (hid->claimed & HID_CLAIMED_HIDRAW) {
2009 		ret = hidraw_report_event(hid, data, size);
2010 		if (ret)
2011 			goto out;
2012 	}
2013 
2014 	if (hid->claimed != HID_CLAIMED_HIDRAW && report->maxfield) {
2015 		hid_process_report(hid, report, cdata, interrupt);
2016 		hdrv = hid->driver;
2017 		if (hdrv && hdrv->report)
2018 			hdrv->report(hid, report);
2019 	}
2020 
2021 	if (hid->claimed & HID_CLAIMED_INPUT)
2022 		hidinput_report_event(hid, report);
2023 out:
2024 	return ret;
2025 }
2026 EXPORT_SYMBOL_GPL(hid_report_raw_event);
2027 
2028 
2029 static int __hid_input_report(struct hid_device *hid, enum hid_report_type type,
2030 			      u8 *data, u32 size, int interrupt, u64 source, bool from_bpf,
2031 			      bool lock_already_taken)
2032 {
2033 	struct hid_report_enum *report_enum;
2034 	struct hid_driver *hdrv;
2035 	struct hid_report *report;
2036 	int ret = 0;
2037 
2038 	if (!hid)
2039 		return -ENODEV;
2040 
2041 	ret = down_trylock(&hid->driver_input_lock);
2042 	if (lock_already_taken && !ret) {
2043 		up(&hid->driver_input_lock);
2044 		return -EINVAL;
2045 	} else if (!lock_already_taken && ret) {
2046 		return -EBUSY;
2047 	}
2048 
2049 	if (!hid->driver) {
2050 		ret = -ENODEV;
2051 		goto unlock;
2052 	}
2053 	report_enum = hid->report_enum + type;
2054 	hdrv = hid->driver;
2055 
2056 	data = dispatch_hid_bpf_device_event(hid, type, data, &size, interrupt, source, from_bpf);
2057 	if (IS_ERR(data)) {
2058 		ret = PTR_ERR(data);
2059 		goto unlock;
2060 	}
2061 
2062 	if (!size) {
2063 		dbg_hid("empty report\n");
2064 		ret = -1;
2065 		goto unlock;
2066 	}
2067 
2068 	/* Avoid unnecessary overhead if debugfs is disabled */
2069 	if (!list_empty(&hid->debug_list))
2070 		hid_dump_report(hid, type, data, size);
2071 
2072 	report = hid_get_report(report_enum, data);
2073 
2074 	if (!report) {
2075 		ret = -1;
2076 		goto unlock;
2077 	}
2078 
2079 	if (hdrv && hdrv->raw_event && hid_match_report(hid, report)) {
2080 		ret = hdrv->raw_event(hid, report, data, size);
2081 		if (ret < 0)
2082 			goto unlock;
2083 	}
2084 
2085 	ret = hid_report_raw_event(hid, type, data, size, interrupt);
2086 
2087 unlock:
2088 	if (!lock_already_taken)
2089 		up(&hid->driver_input_lock);
2090 	return ret;
2091 }
2092 
2093 /**
2094  * hid_input_report - report data from lower layer (usb, bt...)
2095  *
2096  * @hid: hid device
2097  * @type: HID report type (HID_*_REPORT)
2098  * @data: report contents
2099  * @size: size of data parameter
2100  * @interrupt: distinguish between interrupt and control transfers
2101  *
2102  * This is data entry for lower layers.
2103  */
2104 int hid_input_report(struct hid_device *hid, enum hid_report_type type, u8 *data, u32 size,
2105 		     int interrupt)
2106 {
2107 	return __hid_input_report(hid, type, data, size, interrupt, 0,
2108 				  false, /* from_bpf */
2109 				  false /* lock_already_taken */);
2110 }
2111 EXPORT_SYMBOL_GPL(hid_input_report);
2112 
2113 bool hid_match_one_id(const struct hid_device *hdev,
2114 		      const struct hid_device_id *id)
2115 {
2116 	return (id->bus == HID_BUS_ANY || id->bus == hdev->bus) &&
2117 		(id->group == HID_GROUP_ANY || id->group == hdev->group) &&
2118 		(id->vendor == HID_ANY_ID || id->vendor == hdev->vendor) &&
2119 		(id->product == HID_ANY_ID || id->product == hdev->product);
2120 }
2121 
2122 const struct hid_device_id *hid_match_id(const struct hid_device *hdev,
2123 		const struct hid_device_id *id)
2124 {
2125 	for (; id->bus; id++)
2126 		if (hid_match_one_id(hdev, id))
2127 			return id;
2128 
2129 	return NULL;
2130 }
2131 EXPORT_SYMBOL_GPL(hid_match_id);
2132 
2133 static const struct hid_device_id hid_hiddev_list[] = {
2134 	{ HID_USB_DEVICE(USB_VENDOR_ID_MGE, USB_DEVICE_ID_MGE_UPS) },
2135 	{ HID_USB_DEVICE(USB_VENDOR_ID_MGE, USB_DEVICE_ID_MGE_UPS1) },
2136 	{ }
2137 };
2138 
2139 static bool hid_hiddev(struct hid_device *hdev)
2140 {
2141 	return !!hid_match_id(hdev, hid_hiddev_list);
2142 }
2143 
2144 
2145 static ssize_t
2146 read_report_descriptor(struct file *filp, struct kobject *kobj,
2147 		struct bin_attribute *attr,
2148 		char *buf, loff_t off, size_t count)
2149 {
2150 	struct device *dev = kobj_to_dev(kobj);
2151 	struct hid_device *hdev = to_hid_device(dev);
2152 
2153 	if (off >= hdev->rsize)
2154 		return 0;
2155 
2156 	if (off + count > hdev->rsize)
2157 		count = hdev->rsize - off;
2158 
2159 	memcpy(buf, hdev->rdesc + off, count);
2160 
2161 	return count;
2162 }
2163 
2164 static ssize_t
2165 show_country(struct device *dev, struct device_attribute *attr,
2166 		char *buf)
2167 {
2168 	struct hid_device *hdev = to_hid_device(dev);
2169 
2170 	return sprintf(buf, "%02x\n", hdev->country & 0xff);
2171 }
2172 
2173 static struct bin_attribute dev_bin_attr_report_desc = {
2174 	.attr = { .name = "report_descriptor", .mode = 0444 },
2175 	.read = read_report_descriptor,
2176 	.size = HID_MAX_DESCRIPTOR_SIZE,
2177 };
2178 
2179 static const struct device_attribute dev_attr_country = {
2180 	.attr = { .name = "country", .mode = 0444 },
2181 	.show = show_country,
2182 };
2183 
2184 int hid_connect(struct hid_device *hdev, unsigned int connect_mask)
2185 {
2186 	static const char *types[] = { "Device", "Pointer", "Mouse", "Device",
2187 		"Joystick", "Gamepad", "Keyboard", "Keypad",
2188 		"Multi-Axis Controller"
2189 	};
2190 	const char *type, *bus;
2191 	char buf[64] = "";
2192 	unsigned int i;
2193 	int len;
2194 	int ret;
2195 
2196 	ret = hid_bpf_connect_device(hdev);
2197 	if (ret)
2198 		return ret;
2199 
2200 	if (hdev->quirks & HID_QUIRK_HIDDEV_FORCE)
2201 		connect_mask |= (HID_CONNECT_HIDDEV_FORCE | HID_CONNECT_HIDDEV);
2202 	if (hdev->quirks & HID_QUIRK_HIDINPUT_FORCE)
2203 		connect_mask |= HID_CONNECT_HIDINPUT_FORCE;
2204 	if (hdev->bus != BUS_USB)
2205 		connect_mask &= ~HID_CONNECT_HIDDEV;
2206 	if (hid_hiddev(hdev))
2207 		connect_mask |= HID_CONNECT_HIDDEV_FORCE;
2208 
2209 	if ((connect_mask & HID_CONNECT_HIDINPUT) && !hidinput_connect(hdev,
2210 				connect_mask & HID_CONNECT_HIDINPUT_FORCE))
2211 		hdev->claimed |= HID_CLAIMED_INPUT;
2212 
2213 	if ((connect_mask & HID_CONNECT_HIDDEV) && hdev->hiddev_connect &&
2214 			!hdev->hiddev_connect(hdev,
2215 				connect_mask & HID_CONNECT_HIDDEV_FORCE))
2216 		hdev->claimed |= HID_CLAIMED_HIDDEV;
2217 	if ((connect_mask & HID_CONNECT_HIDRAW) && !hidraw_connect(hdev))
2218 		hdev->claimed |= HID_CLAIMED_HIDRAW;
2219 
2220 	if (connect_mask & HID_CONNECT_DRIVER)
2221 		hdev->claimed |= HID_CLAIMED_DRIVER;
2222 
2223 	/* Drivers with the ->raw_event callback set are not required to connect
2224 	 * to any other listener. */
2225 	if (!hdev->claimed && !hdev->driver->raw_event) {
2226 		hid_err(hdev, "device has no listeners, quitting\n");
2227 		return -ENODEV;
2228 	}
2229 
2230 	hid_process_ordering(hdev);
2231 
2232 	if ((hdev->claimed & HID_CLAIMED_INPUT) &&
2233 			(connect_mask & HID_CONNECT_FF) && hdev->ff_init)
2234 		hdev->ff_init(hdev);
2235 
2236 	len = 0;
2237 	if (hdev->claimed & HID_CLAIMED_INPUT)
2238 		len += sprintf(buf + len, "input");
2239 	if (hdev->claimed & HID_CLAIMED_HIDDEV)
2240 		len += sprintf(buf + len, "%shiddev%d", len ? "," : "",
2241 				((struct hiddev *)hdev->hiddev)->minor);
2242 	if (hdev->claimed & HID_CLAIMED_HIDRAW)
2243 		len += sprintf(buf + len, "%shidraw%d", len ? "," : "",
2244 				((struct hidraw *)hdev->hidraw)->minor);
2245 
2246 	type = "Device";
2247 	for (i = 0; i < hdev->maxcollection; i++) {
2248 		struct hid_collection *col = &hdev->collection[i];
2249 		if (col->type == HID_COLLECTION_APPLICATION &&
2250 		   (col->usage & HID_USAGE_PAGE) == HID_UP_GENDESK &&
2251 		   (col->usage & 0xffff) < ARRAY_SIZE(types)) {
2252 			type = types[col->usage & 0xffff];
2253 			break;
2254 		}
2255 	}
2256 
2257 	switch (hdev->bus) {
2258 	case BUS_USB:
2259 		bus = "USB";
2260 		break;
2261 	case BUS_BLUETOOTH:
2262 		bus = "BLUETOOTH";
2263 		break;
2264 	case BUS_I2C:
2265 		bus = "I2C";
2266 		break;
2267 	case BUS_VIRTUAL:
2268 		bus = "VIRTUAL";
2269 		break;
2270 	case BUS_INTEL_ISHTP:
2271 	case BUS_AMD_SFH:
2272 		bus = "SENSOR HUB";
2273 		break;
2274 	default:
2275 		bus = "<UNKNOWN>";
2276 	}
2277 
2278 	ret = device_create_file(&hdev->dev, &dev_attr_country);
2279 	if (ret)
2280 		hid_warn(hdev,
2281 			 "can't create sysfs country code attribute err: %d\n", ret);
2282 
2283 	hid_info(hdev, "%s: %s HID v%x.%02x %s [%s] on %s\n",
2284 		 buf, bus, hdev->version >> 8, hdev->version & 0xff,
2285 		 type, hdev->name, hdev->phys);
2286 
2287 	return 0;
2288 }
2289 EXPORT_SYMBOL_GPL(hid_connect);
2290 
2291 void hid_disconnect(struct hid_device *hdev)
2292 {
2293 	device_remove_file(&hdev->dev, &dev_attr_country);
2294 	if (hdev->claimed & HID_CLAIMED_INPUT)
2295 		hidinput_disconnect(hdev);
2296 	if (hdev->claimed & HID_CLAIMED_HIDDEV)
2297 		hdev->hiddev_disconnect(hdev);
2298 	if (hdev->claimed & HID_CLAIMED_HIDRAW)
2299 		hidraw_disconnect(hdev);
2300 	hdev->claimed = 0;
2301 
2302 	hid_bpf_disconnect_device(hdev);
2303 }
2304 EXPORT_SYMBOL_GPL(hid_disconnect);
2305 
2306 /**
2307  * hid_hw_start - start underlying HW
2308  * @hdev: hid device
2309  * @connect_mask: which outputs to connect, see HID_CONNECT_*
2310  *
2311  * Call this in probe function *after* hid_parse. This will setup HW
2312  * buffers and start the device (if not defeirred to device open).
2313  * hid_hw_stop must be called if this was successful.
2314  */
2315 int hid_hw_start(struct hid_device *hdev, unsigned int connect_mask)
2316 {
2317 	int error;
2318 
2319 	error = hdev->ll_driver->start(hdev);
2320 	if (error)
2321 		return error;
2322 
2323 	if (connect_mask) {
2324 		error = hid_connect(hdev, connect_mask);
2325 		if (error) {
2326 			hdev->ll_driver->stop(hdev);
2327 			return error;
2328 		}
2329 	}
2330 
2331 	return 0;
2332 }
2333 EXPORT_SYMBOL_GPL(hid_hw_start);
2334 
2335 /**
2336  * hid_hw_stop - stop underlying HW
2337  * @hdev: hid device
2338  *
2339  * This is usually called from remove function or from probe when something
2340  * failed and hid_hw_start was called already.
2341  */
2342 void hid_hw_stop(struct hid_device *hdev)
2343 {
2344 	hid_disconnect(hdev);
2345 	hdev->ll_driver->stop(hdev);
2346 }
2347 EXPORT_SYMBOL_GPL(hid_hw_stop);
2348 
2349 /**
2350  * hid_hw_open - signal underlying HW to start delivering events
2351  * @hdev: hid device
2352  *
2353  * Tell underlying HW to start delivering events from the device.
2354  * This function should be called sometime after successful call
2355  * to hid_hw_start().
2356  */
2357 int hid_hw_open(struct hid_device *hdev)
2358 {
2359 	int ret;
2360 
2361 	ret = mutex_lock_killable(&hdev->ll_open_lock);
2362 	if (ret)
2363 		return ret;
2364 
2365 	if (!hdev->ll_open_count++) {
2366 		ret = hdev->ll_driver->open(hdev);
2367 		if (ret)
2368 			hdev->ll_open_count--;
2369 	}
2370 
2371 	mutex_unlock(&hdev->ll_open_lock);
2372 	return ret;
2373 }
2374 EXPORT_SYMBOL_GPL(hid_hw_open);
2375 
2376 /**
2377  * hid_hw_close - signal underlaying HW to stop delivering events
2378  *
2379  * @hdev: hid device
2380  *
2381  * This function indicates that we are not interested in the events
2382  * from this device anymore. Delivery of events may or may not stop,
2383  * depending on the number of users still outstanding.
2384  */
2385 void hid_hw_close(struct hid_device *hdev)
2386 {
2387 	mutex_lock(&hdev->ll_open_lock);
2388 	if (!--hdev->ll_open_count)
2389 		hdev->ll_driver->close(hdev);
2390 	mutex_unlock(&hdev->ll_open_lock);
2391 }
2392 EXPORT_SYMBOL_GPL(hid_hw_close);
2393 
2394 /**
2395  * hid_hw_request - send report request to device
2396  *
2397  * @hdev: hid device
2398  * @report: report to send
2399  * @reqtype: hid request type
2400  */
2401 void hid_hw_request(struct hid_device *hdev,
2402 		    struct hid_report *report, enum hid_class_request reqtype)
2403 {
2404 	if (hdev->ll_driver->request)
2405 		return hdev->ll_driver->request(hdev, report, reqtype);
2406 
2407 	__hid_request(hdev, report, reqtype);
2408 }
2409 EXPORT_SYMBOL_GPL(hid_hw_request);
2410 
2411 int __hid_hw_raw_request(struct hid_device *hdev,
2412 			 unsigned char reportnum, __u8 *buf,
2413 			 size_t len, enum hid_report_type rtype,
2414 			 enum hid_class_request reqtype,
2415 			 u64 source, bool from_bpf)
2416 {
2417 	unsigned int max_buffer_size = HID_MAX_BUFFER_SIZE;
2418 	int ret;
2419 
2420 	if (hdev->ll_driver->max_buffer_size)
2421 		max_buffer_size = hdev->ll_driver->max_buffer_size;
2422 
2423 	if (len < 1 || len > max_buffer_size || !buf)
2424 		return -EINVAL;
2425 
2426 	ret = dispatch_hid_bpf_raw_requests(hdev, reportnum, buf, len, rtype,
2427 					    reqtype, source, from_bpf);
2428 	if (ret)
2429 		return ret;
2430 
2431 	return hdev->ll_driver->raw_request(hdev, reportnum, buf, len,
2432 					    rtype, reqtype);
2433 }
2434 
2435 /**
2436  * hid_hw_raw_request - send report request to device
2437  *
2438  * @hdev: hid device
2439  * @reportnum: report ID
2440  * @buf: in/out data to transfer
2441  * @len: length of buf
2442  * @rtype: HID report type
2443  * @reqtype: HID_REQ_GET_REPORT or HID_REQ_SET_REPORT
2444  *
2445  * Return: count of data transferred, negative if error
2446  *
2447  * Same behavior as hid_hw_request, but with raw buffers instead.
2448  */
2449 int hid_hw_raw_request(struct hid_device *hdev,
2450 		       unsigned char reportnum, __u8 *buf,
2451 		       size_t len, enum hid_report_type rtype, enum hid_class_request reqtype)
2452 {
2453 	return __hid_hw_raw_request(hdev, reportnum, buf, len, rtype, reqtype, 0, false);
2454 }
2455 EXPORT_SYMBOL_GPL(hid_hw_raw_request);
2456 
2457 int __hid_hw_output_report(struct hid_device *hdev, __u8 *buf, size_t len, u64 source,
2458 			   bool from_bpf)
2459 {
2460 	unsigned int max_buffer_size = HID_MAX_BUFFER_SIZE;
2461 	int ret;
2462 
2463 	if (hdev->ll_driver->max_buffer_size)
2464 		max_buffer_size = hdev->ll_driver->max_buffer_size;
2465 
2466 	if (len < 1 || len > max_buffer_size || !buf)
2467 		return -EINVAL;
2468 
2469 	ret = dispatch_hid_bpf_output_report(hdev, buf, len, source, from_bpf);
2470 	if (ret)
2471 		return ret;
2472 
2473 	if (hdev->ll_driver->output_report)
2474 		return hdev->ll_driver->output_report(hdev, buf, len);
2475 
2476 	return -ENOSYS;
2477 }
2478 
2479 /**
2480  * hid_hw_output_report - send output report to device
2481  *
2482  * @hdev: hid device
2483  * @buf: raw data to transfer
2484  * @len: length of buf
2485  *
2486  * Return: count of data transferred, negative if error
2487  */
2488 int hid_hw_output_report(struct hid_device *hdev, __u8 *buf, size_t len)
2489 {
2490 	return __hid_hw_output_report(hdev, buf, len, 0, false);
2491 }
2492 EXPORT_SYMBOL_GPL(hid_hw_output_report);
2493 
2494 #ifdef CONFIG_PM
2495 int hid_driver_suspend(struct hid_device *hdev, pm_message_t state)
2496 {
2497 	if (hdev->driver && hdev->driver->suspend)
2498 		return hdev->driver->suspend(hdev, state);
2499 
2500 	return 0;
2501 }
2502 EXPORT_SYMBOL_GPL(hid_driver_suspend);
2503 
2504 int hid_driver_reset_resume(struct hid_device *hdev)
2505 {
2506 	if (hdev->driver && hdev->driver->reset_resume)
2507 		return hdev->driver->reset_resume(hdev);
2508 
2509 	return 0;
2510 }
2511 EXPORT_SYMBOL_GPL(hid_driver_reset_resume);
2512 
2513 int hid_driver_resume(struct hid_device *hdev)
2514 {
2515 	if (hdev->driver && hdev->driver->resume)
2516 		return hdev->driver->resume(hdev);
2517 
2518 	return 0;
2519 }
2520 EXPORT_SYMBOL_GPL(hid_driver_resume);
2521 #endif /* CONFIG_PM */
2522 
2523 struct hid_dynid {
2524 	struct list_head list;
2525 	struct hid_device_id id;
2526 };
2527 
2528 /**
2529  * new_id_store - add a new HID device ID to this driver and re-probe devices
2530  * @drv: target device driver
2531  * @buf: buffer for scanning device ID data
2532  * @count: input size
2533  *
2534  * Adds a new dynamic hid device ID to this driver,
2535  * and causes the driver to probe for all devices again.
2536  */
2537 static ssize_t new_id_store(struct device_driver *drv, const char *buf,
2538 		size_t count)
2539 {
2540 	struct hid_driver *hdrv = to_hid_driver(drv);
2541 	struct hid_dynid *dynid;
2542 	__u32 bus, vendor, product;
2543 	unsigned long driver_data = 0;
2544 	int ret;
2545 
2546 	ret = sscanf(buf, "%x %x %x %lx",
2547 			&bus, &vendor, &product, &driver_data);
2548 	if (ret < 3)
2549 		return -EINVAL;
2550 
2551 	dynid = kzalloc(sizeof(*dynid), GFP_KERNEL);
2552 	if (!dynid)
2553 		return -ENOMEM;
2554 
2555 	dynid->id.bus = bus;
2556 	dynid->id.group = HID_GROUP_ANY;
2557 	dynid->id.vendor = vendor;
2558 	dynid->id.product = product;
2559 	dynid->id.driver_data = driver_data;
2560 
2561 	spin_lock(&hdrv->dyn_lock);
2562 	list_add_tail(&dynid->list, &hdrv->dyn_list);
2563 	spin_unlock(&hdrv->dyn_lock);
2564 
2565 	ret = driver_attach(&hdrv->driver);
2566 
2567 	return ret ? : count;
2568 }
2569 static DRIVER_ATTR_WO(new_id);
2570 
2571 static struct attribute *hid_drv_attrs[] = {
2572 	&driver_attr_new_id.attr,
2573 	NULL,
2574 };
2575 ATTRIBUTE_GROUPS(hid_drv);
2576 
2577 static void hid_free_dynids(struct hid_driver *hdrv)
2578 {
2579 	struct hid_dynid *dynid, *n;
2580 
2581 	spin_lock(&hdrv->dyn_lock);
2582 	list_for_each_entry_safe(dynid, n, &hdrv->dyn_list, list) {
2583 		list_del(&dynid->list);
2584 		kfree(dynid);
2585 	}
2586 	spin_unlock(&hdrv->dyn_lock);
2587 }
2588 
2589 const struct hid_device_id *hid_match_device(struct hid_device *hdev,
2590 					     struct hid_driver *hdrv)
2591 {
2592 	struct hid_dynid *dynid;
2593 
2594 	spin_lock(&hdrv->dyn_lock);
2595 	list_for_each_entry(dynid, &hdrv->dyn_list, list) {
2596 		if (hid_match_one_id(hdev, &dynid->id)) {
2597 			spin_unlock(&hdrv->dyn_lock);
2598 			return &dynid->id;
2599 		}
2600 	}
2601 	spin_unlock(&hdrv->dyn_lock);
2602 
2603 	return hid_match_id(hdev, hdrv->id_table);
2604 }
2605 EXPORT_SYMBOL_GPL(hid_match_device);
2606 
2607 static int hid_bus_match(struct device *dev, const struct device_driver *drv)
2608 {
2609 	struct hid_driver *hdrv = to_hid_driver(drv);
2610 	struct hid_device *hdev = to_hid_device(dev);
2611 
2612 	return hid_match_device(hdev, hdrv) != NULL;
2613 }
2614 
2615 /**
2616  * hid_compare_device_paths - check if both devices share the same path
2617  * @hdev_a: hid device
2618  * @hdev_b: hid device
2619  * @separator: char to use as separator
2620  *
2621  * Check if two devices share the same path up to the last occurrence of
2622  * the separator char. Both paths must exist (i.e., zero-length paths
2623  * don't match).
2624  */
2625 bool hid_compare_device_paths(struct hid_device *hdev_a,
2626 			      struct hid_device *hdev_b, char separator)
2627 {
2628 	int n1 = strrchr(hdev_a->phys, separator) - hdev_a->phys;
2629 	int n2 = strrchr(hdev_b->phys, separator) - hdev_b->phys;
2630 
2631 	if (n1 != n2 || n1 <= 0 || n2 <= 0)
2632 		return false;
2633 
2634 	return !strncmp(hdev_a->phys, hdev_b->phys, n1);
2635 }
2636 EXPORT_SYMBOL_GPL(hid_compare_device_paths);
2637 
2638 static bool hid_check_device_match(struct hid_device *hdev,
2639 				   struct hid_driver *hdrv,
2640 				   const struct hid_device_id **id)
2641 {
2642 	*id = hid_match_device(hdev, hdrv);
2643 	if (!*id)
2644 		return false;
2645 
2646 	if (hdrv->match)
2647 		return hdrv->match(hdev, hid_ignore_special_drivers);
2648 
2649 	/*
2650 	 * hid-generic implements .match(), so we must be dealing with a
2651 	 * different HID driver here, and can simply check if
2652 	 * hid_ignore_special_drivers is set or not.
2653 	 */
2654 	return !hid_ignore_special_drivers;
2655 }
2656 
2657 static int __hid_device_probe(struct hid_device *hdev, struct hid_driver *hdrv)
2658 {
2659 	const struct hid_device_id *id;
2660 	int ret;
2661 
2662 	if (!hid_check_device_match(hdev, hdrv, &id))
2663 		return -ENODEV;
2664 
2665 	hdev->devres_group_id = devres_open_group(&hdev->dev, NULL, GFP_KERNEL);
2666 	if (!hdev->devres_group_id)
2667 		return -ENOMEM;
2668 
2669 	/* reset the quirks that has been previously set */
2670 	hdev->quirks = hid_lookup_quirk(hdev);
2671 	hdev->driver = hdrv;
2672 
2673 	if (hdrv->probe) {
2674 		ret = hdrv->probe(hdev, id);
2675 	} else { /* default probe */
2676 		ret = hid_open_report(hdev);
2677 		if (!ret)
2678 			ret = hid_hw_start(hdev, HID_CONNECT_DEFAULT);
2679 	}
2680 
2681 	/*
2682 	 * Note that we are not closing the devres group opened above so
2683 	 * even resources that were attached to the device after probe is
2684 	 * run are released when hid_device_remove() is executed. This is
2685 	 * needed as some drivers would allocate additional resources,
2686 	 * for example when updating firmware.
2687 	 */
2688 
2689 	if (ret) {
2690 		devres_release_group(&hdev->dev, hdev->devres_group_id);
2691 		hid_close_report(hdev);
2692 		hdev->driver = NULL;
2693 	}
2694 
2695 	return ret;
2696 }
2697 
2698 static int hid_device_probe(struct device *dev)
2699 {
2700 	struct hid_device *hdev = to_hid_device(dev);
2701 	struct hid_driver *hdrv = to_hid_driver(dev->driver);
2702 	int ret = 0;
2703 
2704 	if (down_interruptible(&hdev->driver_input_lock))
2705 		return -EINTR;
2706 
2707 	hdev->io_started = false;
2708 	clear_bit(ffs(HID_STAT_REPROBED), &hdev->status);
2709 
2710 	if (!hdev->driver)
2711 		ret = __hid_device_probe(hdev, hdrv);
2712 
2713 	if (!hdev->io_started)
2714 		up(&hdev->driver_input_lock);
2715 
2716 	return ret;
2717 }
2718 
2719 static void hid_device_remove(struct device *dev)
2720 {
2721 	struct hid_device *hdev = to_hid_device(dev);
2722 	struct hid_driver *hdrv;
2723 
2724 	down(&hdev->driver_input_lock);
2725 	hdev->io_started = false;
2726 
2727 	hdrv = hdev->driver;
2728 	if (hdrv) {
2729 		if (hdrv->remove)
2730 			hdrv->remove(hdev);
2731 		else /* default remove */
2732 			hid_hw_stop(hdev);
2733 
2734 		/* Release all devres resources allocated by the driver */
2735 		devres_release_group(&hdev->dev, hdev->devres_group_id);
2736 
2737 		hid_close_report(hdev);
2738 		hdev->driver = NULL;
2739 	}
2740 
2741 	if (!hdev->io_started)
2742 		up(&hdev->driver_input_lock);
2743 }
2744 
2745 static ssize_t modalias_show(struct device *dev, struct device_attribute *a,
2746 			     char *buf)
2747 {
2748 	struct hid_device *hdev = container_of(dev, struct hid_device, dev);
2749 
2750 	return scnprintf(buf, PAGE_SIZE, "hid:b%04Xg%04Xv%08Xp%08X\n",
2751 			 hdev->bus, hdev->group, hdev->vendor, hdev->product);
2752 }
2753 static DEVICE_ATTR_RO(modalias);
2754 
2755 static struct attribute *hid_dev_attrs[] = {
2756 	&dev_attr_modalias.attr,
2757 	NULL,
2758 };
2759 static struct bin_attribute *hid_dev_bin_attrs[] = {
2760 	&dev_bin_attr_report_desc,
2761 	NULL
2762 };
2763 static const struct attribute_group hid_dev_group = {
2764 	.attrs = hid_dev_attrs,
2765 	.bin_attrs = hid_dev_bin_attrs,
2766 };
2767 __ATTRIBUTE_GROUPS(hid_dev);
2768 
2769 static int hid_uevent(const struct device *dev, struct kobj_uevent_env *env)
2770 {
2771 	const struct hid_device *hdev = to_hid_device(dev);
2772 
2773 	if (add_uevent_var(env, "HID_ID=%04X:%08X:%08X",
2774 			hdev->bus, hdev->vendor, hdev->product))
2775 		return -ENOMEM;
2776 
2777 	if (add_uevent_var(env, "HID_NAME=%s", hdev->name))
2778 		return -ENOMEM;
2779 
2780 	if (add_uevent_var(env, "HID_PHYS=%s", hdev->phys))
2781 		return -ENOMEM;
2782 
2783 	if (add_uevent_var(env, "HID_UNIQ=%s", hdev->uniq))
2784 		return -ENOMEM;
2785 
2786 	if (add_uevent_var(env, "MODALIAS=hid:b%04Xg%04Xv%08Xp%08X",
2787 			   hdev->bus, hdev->group, hdev->vendor, hdev->product))
2788 		return -ENOMEM;
2789 
2790 	return 0;
2791 }
2792 
2793 const struct bus_type hid_bus_type = {
2794 	.name		= "hid",
2795 	.dev_groups	= hid_dev_groups,
2796 	.drv_groups	= hid_drv_groups,
2797 	.match		= hid_bus_match,
2798 	.probe		= hid_device_probe,
2799 	.remove		= hid_device_remove,
2800 	.uevent		= hid_uevent,
2801 };
2802 EXPORT_SYMBOL(hid_bus_type);
2803 
2804 int hid_add_device(struct hid_device *hdev)
2805 {
2806 	static atomic_t id = ATOMIC_INIT(0);
2807 	int ret;
2808 
2809 	if (WARN_ON(hdev->status & HID_STAT_ADDED))
2810 		return -EBUSY;
2811 
2812 	hdev->quirks = hid_lookup_quirk(hdev);
2813 
2814 	/* we need to kill them here, otherwise they will stay allocated to
2815 	 * wait for coming driver */
2816 	if (hid_ignore(hdev))
2817 		return -ENODEV;
2818 
2819 	/*
2820 	 * Check for the mandatory transport channel.
2821 	 */
2822 	 if (!hdev->ll_driver->raw_request) {
2823 		hid_err(hdev, "transport driver missing .raw_request()\n");
2824 		return -EINVAL;
2825 	 }
2826 
2827 	/*
2828 	 * Read the device report descriptor once and use as template
2829 	 * for the driver-specific modifications.
2830 	 */
2831 	ret = hdev->ll_driver->parse(hdev);
2832 	if (ret)
2833 		return ret;
2834 	if (!hdev->dev_rdesc)
2835 		return -ENODEV;
2836 
2837 	/*
2838 	 * Scan generic devices for group information
2839 	 */
2840 	if (hid_ignore_special_drivers) {
2841 		hdev->group = HID_GROUP_GENERIC;
2842 	} else if (!hdev->group &&
2843 		   !(hdev->quirks & HID_QUIRK_HAVE_SPECIAL_DRIVER)) {
2844 		ret = hid_scan_report(hdev);
2845 		if (ret)
2846 			hid_warn(hdev, "bad device descriptor (%d)\n", ret);
2847 	}
2848 
2849 	hdev->id = atomic_inc_return(&id);
2850 
2851 	/* XXX hack, any other cleaner solution after the driver core
2852 	 * is converted to allow more than 20 bytes as the device name? */
2853 	dev_set_name(&hdev->dev, "%04X:%04X:%04X.%04X", hdev->bus,
2854 		     hdev->vendor, hdev->product, hdev->id);
2855 
2856 	hid_debug_register(hdev, dev_name(&hdev->dev));
2857 	ret = device_add(&hdev->dev);
2858 	if (!ret)
2859 		hdev->status |= HID_STAT_ADDED;
2860 	else
2861 		hid_debug_unregister(hdev);
2862 
2863 	return ret;
2864 }
2865 EXPORT_SYMBOL_GPL(hid_add_device);
2866 
2867 /**
2868  * hid_allocate_device - allocate new hid device descriptor
2869  *
2870  * Allocate and initialize hid device, so that hid_destroy_device might be
2871  * used to free it.
2872  *
2873  * New hid_device pointer is returned on success, otherwise ERR_PTR encoded
2874  * error value.
2875  */
2876 struct hid_device *hid_allocate_device(void)
2877 {
2878 	struct hid_device *hdev;
2879 	int ret = -ENOMEM;
2880 
2881 	hdev = kzalloc(sizeof(*hdev), GFP_KERNEL);
2882 	if (hdev == NULL)
2883 		return ERR_PTR(ret);
2884 
2885 	device_initialize(&hdev->dev);
2886 	hdev->dev.release = hid_device_release;
2887 	hdev->dev.bus = &hid_bus_type;
2888 	device_enable_async_suspend(&hdev->dev);
2889 
2890 	hid_close_report(hdev);
2891 
2892 	init_waitqueue_head(&hdev->debug_wait);
2893 	INIT_LIST_HEAD(&hdev->debug_list);
2894 	spin_lock_init(&hdev->debug_list_lock);
2895 	sema_init(&hdev->driver_input_lock, 1);
2896 	mutex_init(&hdev->ll_open_lock);
2897 	kref_init(&hdev->ref);
2898 
2899 	ret = hid_bpf_device_init(hdev);
2900 	if (ret)
2901 		goto out_err;
2902 
2903 	return hdev;
2904 
2905 out_err:
2906 	hid_destroy_device(hdev);
2907 	return ERR_PTR(ret);
2908 }
2909 EXPORT_SYMBOL_GPL(hid_allocate_device);
2910 
2911 static void hid_remove_device(struct hid_device *hdev)
2912 {
2913 	if (hdev->status & HID_STAT_ADDED) {
2914 		device_del(&hdev->dev);
2915 		hid_debug_unregister(hdev);
2916 		hdev->status &= ~HID_STAT_ADDED;
2917 	}
2918 	kfree(hdev->dev_rdesc);
2919 	hdev->dev_rdesc = NULL;
2920 	hdev->dev_rsize = 0;
2921 }
2922 
2923 /**
2924  * hid_destroy_device - free previously allocated device
2925  *
2926  * @hdev: hid device
2927  *
2928  * If you allocate hid_device through hid_allocate_device, you should ever
2929  * free by this function.
2930  */
2931 void hid_destroy_device(struct hid_device *hdev)
2932 {
2933 	hid_bpf_destroy_device(hdev);
2934 	hid_remove_device(hdev);
2935 	put_device(&hdev->dev);
2936 }
2937 EXPORT_SYMBOL_GPL(hid_destroy_device);
2938 
2939 
2940 static int __hid_bus_reprobe_drivers(struct device *dev, void *data)
2941 {
2942 	struct hid_driver *hdrv = data;
2943 	struct hid_device *hdev = to_hid_device(dev);
2944 
2945 	if (hdev->driver == hdrv &&
2946 	    !hdrv->match(hdev, hid_ignore_special_drivers) &&
2947 	    !test_and_set_bit(ffs(HID_STAT_REPROBED), &hdev->status))
2948 		return device_reprobe(dev);
2949 
2950 	return 0;
2951 }
2952 
2953 static int __hid_bus_driver_added(struct device_driver *drv, void *data)
2954 {
2955 	struct hid_driver *hdrv = to_hid_driver(drv);
2956 
2957 	if (hdrv->match) {
2958 		bus_for_each_dev(&hid_bus_type, NULL, hdrv,
2959 				 __hid_bus_reprobe_drivers);
2960 	}
2961 
2962 	return 0;
2963 }
2964 
2965 static int __bus_removed_driver(struct device_driver *drv, void *data)
2966 {
2967 	return bus_rescan_devices(&hid_bus_type);
2968 }
2969 
2970 int __hid_register_driver(struct hid_driver *hdrv, struct module *owner,
2971 		const char *mod_name)
2972 {
2973 	int ret;
2974 
2975 	hdrv->driver.name = hdrv->name;
2976 	hdrv->driver.bus = &hid_bus_type;
2977 	hdrv->driver.owner = owner;
2978 	hdrv->driver.mod_name = mod_name;
2979 
2980 	INIT_LIST_HEAD(&hdrv->dyn_list);
2981 	spin_lock_init(&hdrv->dyn_lock);
2982 
2983 	ret = driver_register(&hdrv->driver);
2984 
2985 	if (ret == 0)
2986 		bus_for_each_drv(&hid_bus_type, NULL, NULL,
2987 				 __hid_bus_driver_added);
2988 
2989 	return ret;
2990 }
2991 EXPORT_SYMBOL_GPL(__hid_register_driver);
2992 
2993 void hid_unregister_driver(struct hid_driver *hdrv)
2994 {
2995 	driver_unregister(&hdrv->driver);
2996 	hid_free_dynids(hdrv);
2997 
2998 	bus_for_each_drv(&hid_bus_type, NULL, hdrv, __bus_removed_driver);
2999 }
3000 EXPORT_SYMBOL_GPL(hid_unregister_driver);
3001 
3002 int hid_check_keys_pressed(struct hid_device *hid)
3003 {
3004 	struct hid_input *hidinput;
3005 	int i;
3006 
3007 	if (!(hid->claimed & HID_CLAIMED_INPUT))
3008 		return 0;
3009 
3010 	list_for_each_entry(hidinput, &hid->inputs, list) {
3011 		for (i = 0; i < BITS_TO_LONGS(KEY_MAX); i++)
3012 			if (hidinput->input->key[i])
3013 				return 1;
3014 	}
3015 
3016 	return 0;
3017 }
3018 EXPORT_SYMBOL_GPL(hid_check_keys_pressed);
3019 
3020 #ifdef CONFIG_HID_BPF
3021 static struct hid_ops __hid_ops = {
3022 	.hid_get_report = hid_get_report,
3023 	.hid_hw_raw_request = __hid_hw_raw_request,
3024 	.hid_hw_output_report = __hid_hw_output_report,
3025 	.hid_input_report = __hid_input_report,
3026 	.owner = THIS_MODULE,
3027 	.bus_type = &hid_bus_type,
3028 };
3029 #endif
3030 
3031 static int __init hid_init(void)
3032 {
3033 	int ret;
3034 
3035 	ret = bus_register(&hid_bus_type);
3036 	if (ret) {
3037 		pr_err("can't register hid bus\n");
3038 		goto err;
3039 	}
3040 
3041 #ifdef CONFIG_HID_BPF
3042 	hid_ops = &__hid_ops;
3043 #endif
3044 
3045 	ret = hidraw_init();
3046 	if (ret)
3047 		goto err_bus;
3048 
3049 	hid_debug_init();
3050 
3051 	return 0;
3052 err_bus:
3053 	bus_unregister(&hid_bus_type);
3054 err:
3055 	return ret;
3056 }
3057 
3058 static void __exit hid_exit(void)
3059 {
3060 #ifdef CONFIG_HID_BPF
3061 	hid_ops = NULL;
3062 #endif
3063 	hid_debug_exit();
3064 	hidraw_exit();
3065 	bus_unregister(&hid_bus_type);
3066 	hid_quirks_exit(HID_BUS_ANY);
3067 }
3068 
3069 module_init(hid_init);
3070 module_exit(hid_exit);
3071 
3072 MODULE_AUTHOR("Andreas Gal");
3073 MODULE_AUTHOR("Vojtech Pavlik");
3074 MODULE_AUTHOR("Jiri Kosina");
3075 MODULE_DESCRIPTION("HID support for Linux");
3076 MODULE_LICENSE("GPL");
3077