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