summaryrefslogtreecommitdiffstats
path: root/drivers/platform/x86/wmi.c
blob: c669676ea8e8a6448e089161bd631f9e1b753e4c (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *  ACPI-WMI mapping driver
 *
 *  Copyright (C) 2007-2008 Carlos Corbacho <carlos@strangeworlds.co.uk>
 *
 *  GUID parsing code from ldm.c is:
 *   Copyright (C) 2001,2002 Richard Russon <ldm@flatcap.org>
 *   Copyright (c) 2001-2007 Anton Altaparmakov
 *   Copyright (C) 2001,2002 Jakob Kemi <jakob.kemi@telia.com>
 *
 *  WMI bus infrastructure by Andrew Lutomirski and Darren Hart:
 *    Copyright (C) 2015 Andrew Lutomirski
 *    Copyright (C) 2017 VMware, Inc. All Rights Reserved.
 */

#define pr_fmt(fmt)	KBUILD_MODNAME ": " fmt

#include <linux/acpi.h>
#include <linux/device.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/miscdevice.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/uaccess.h>
#include <linux/uuid.h>
#include <linux/wmi.h>
#include <linux/fs.h>
#include <uapi/linux/wmi.h>

ACPI_MODULE_NAME("wmi");
MODULE_AUTHOR("Carlos Corbacho");
MODULE_DESCRIPTION("ACPI-WMI Mapping Driver");
MODULE_LICENSE("GPL");

static LIST_HEAD(wmi_block_list);

struct guid_block {
	char guid[16];
	union {
		char object_id[2];
		struct {
			unsigned char notify_id;
			unsigned char reserved;
		};
	};
	u8 instance_count;
	u8 flags;
};

struct wmi_block {
	struct wmi_device dev;
	struct list_head list;
	struct guid_block gblock;
	struct miscdevice char_dev;
	struct mutex char_mutex;
	struct acpi_device *acpi_device;
	wmi_notify_handler handler;
	void *handler_data;
	u64 req_buf_size;

	bool read_takes_no_args;
};


/*
 * If the GUID data block is marked as expensive, we must enable and
 * explicitily disable data collection.
 */
#define ACPI_WMI_EXPENSIVE   0x1
#define ACPI_WMI_METHOD      0x2	/* GUID is a method */
#define ACPI_WMI_STRING      0x4	/* GUID takes & returns a string */
#define ACPI_WMI_EVENT       0x8	/* GUID is an event */

static bool debug_event;
module_param(debug_event, bool, 0444);
MODULE_PARM_DESC(debug_event,
		 "Log WMI Events [0/1]");

static bool debug_dump_wdg;
module_param(debug_dump_wdg, bool, 0444);
MODULE_PARM_DESC(debug_dump_wdg,
		 "Dump available WMI interfaces [0/1]");

static int acpi_wmi_remove(struct platform_device *device);
static int acpi_wmi_probe(struct platform_device *device);

static const struct acpi_device_id wmi_device_ids[] = {
	{"PNP0C14", 0},
	{"pnp0c14", 0},
	{"", 0},
};
MODULE_DEVICE_TABLE(acpi, wmi_device_ids);

static struct platform_driver acpi_wmi_driver = {
	.driver = {
		.name = "acpi-wmi",
		.acpi_match_table = wmi_device_ids,
	},
	.probe = acpi_wmi_probe,
	.remove = acpi_wmi_remove,
};

/*
 * GUID parsing functions
 */

static bool find_guid(const char *guid_string, struct wmi_block **out)
{
	guid_t guid_input;
	struct wmi_block *wblock;
	struct guid_block *block;

	if (guid_parse(guid_string, &guid_input))
		return false;

	list_for_each_entry(wblock, &wmi_block_list, list) {
		block = &wblock->gblock;

		if (memcmp(block->guid, &guid_input, 16) == 0) {
			if (out)
				*out = wblock;
			return true;
		}
	}
	return false;
}

static const void *find_guid_context(struct wmi_block *wblock,
				      struct wmi_driver *wdriver)
{
	const struct wmi_device_id *id;
	guid_t guid_input;

	if (wblock == NULL || wdriver == NULL)
		return NULL;
	if (wdriver->id_table == NULL)
		return NULL;

	id = wdriver->id_table;
	while (*id->guid_string) {
		if (guid_parse(id->guid_string, &guid_input))
			continue;
		if (!memcmp(wblock->gblock.guid, &guid_input, 16))
			return id->context;
		id++;
	}
	return NULL;
}

static int get_subobj_info(acpi_handle handle, const char *pathname,
			   struct acpi_device_info **info)
{
	struct acpi_device_info *dummy_info, **info_ptr;
	acpi_handle subobj_handle;
	acpi_status status;

	status = acpi_get_handle(handle, (char *)pathname, &subobj_handle);
	if (status == AE_NOT_FOUND)
		return -ENOENT;
	else if (ACPI_FAILURE(status))
		return -EIO;

	info_ptr = info ? info : &dummy_info;
	status = acpi_get_object_info(subobj_handle, info_ptr);
	if (ACPI_FAILURE(status))
		return -EIO;

	if (!info)
		kfree(dummy_info);

	return 0;
}

static acpi_status wmi_method_enable(struct wmi_block *wblock, int enable)
{
	struct guid_block *block = NULL;
	char method[5];
	acpi_status status;
	acpi_handle handle;

	block = &wblock->gblock;
	handle = wblock->acpi_device->handle;

	snprintf(method, 5, "WE%02X", block->notify_id);
	status = acpi_execute_simple_method(handle, method, enable);

	if (status != AE_OK && status != AE_NOT_FOUND)
		return status;
	else
		return AE_OK;
}

/*
 * Exported WMI functions
 */

/**
 * set_required_buffer_size - Sets the buffer size needed for performing IOCTL
 * @wdev: A wmi bus device from a driver
 * @length: Required buffer size
 *
 * Allocates memory needed for buffer, stores the buffer size in that memory
 */
int set_required_buffer_size(struct wmi_device *wdev, u64 length)
{
	struct wmi_block *wblock;

	wblock = container_of(wdev, struct wmi_block, dev);
	wblock->req_buf_size = length;

	return 0;
}
EXPORT_SYMBOL_GPL(set_required_buffer_size);

/**
 * wmi_evaluate_method - Evaluate a WMI method
 * @guid_string: 36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
 * @instance: Instance index
 * @method_id: Method ID to call
 * @in: Buffer containing input for the method call
 * @out: Empty buffer to return the method results
 *
 * Call an ACPI-WMI method
 */
acpi_status wmi_evaluate_method(const char *guid_string, u8 instance,
u32 method_id, const struct acpi_buffer *in, struct acpi_buffer *out)
{
	struct wmi_block *wblock = NULL;

	if (!find_guid(guid_string, &wblock))
		return AE_ERROR;
	return wmidev_evaluate_method(&wblock->dev, instance, method_id,
				      in, out);
}
EXPORT_SYMBOL_GPL(wmi_evaluate_method);

/**
 * wmidev_evaluate_method - Evaluate a WMI method
 * @wdev: A wmi bus device from a driver
 * @instance: Instance index
 * @method_id: Method ID to call
 * @in: Buffer containing input for the method call
 * @out: Empty buffer to return the method results
 *
 * Call an ACPI-WMI method
 */
acpi_status wmidev_evaluate_method(struct wmi_device *wdev, u8 instance,
	u32 method_id, const struct acpi_buffer *in, struct acpi_buffer *out)
{
	struct guid_block *block = NULL;
	struct wmi_block *wblock = NULL;
	acpi_handle handle;
	acpi_status status;
	struct acpi_object_list input;
	union acpi_object params[3];
	char method[5] = "WM";

	wblock = container_of(wdev, struct wmi_block, dev);
	block = &wblock->gblock;
	handle = wblock->acpi_device->handle;

	if (!(block->flags & ACPI_WMI_METHOD))
		return AE_BAD_DATA;

	if (block->instance_count <= instance)
		return AE_BAD_PARAMETER;

	input.count = 2;
	input.pointer = params;
	params[0].type = ACPI_TYPE_INTEGER;
	params[0].integer.value = instance;
	params[1].type = ACPI_TYPE_INTEGER;
	params[1].integer.value = method_id;

	if (in) {
		input.count = 3;

		if (block->flags & ACPI_WMI_STRING) {
			params[2].type = ACPI_TYPE_STRING;
		} else {
			params[2].type = ACPI_TYPE_BUFFER;
		}
		params[2].buffer.length = in->length;
		params[2].buffer.pointer = in->pointer;
	}

	strncat(method, block->object_id, 2);

	status = acpi_evaluate_object(handle, method, &input, out);

	return status;
}
EXPORT_SYMBOL_GPL(wmidev_evaluate_method);

static acpi_status __query_block(struct wmi_block *wblock, u8 instance,
				 struct acpi_buffer *out)
{
	struct guid_block *block = NULL;
	acpi_handle handle;
	acpi_status status, wc_status = AE_ERROR;
	struct acpi_object_list input;
	union acpi_object wq_params[1];
	char method[5];
	char wc_method[5] = "WC";

	if (!out)
		return AE_BAD_PARAMETER;

	block = &wblock->gblock;
	handle = wblock->acpi_device->handle;

	if (block->instance_count <= instance)
		return AE_BAD_PARAMETER;

	/* Check GUID is a data block */
	if (block->flags & (ACPI_WMI_EVENT | ACPI_WMI_METHOD))
		return AE_ERROR;

	input.count = 1;
	input.pointer = wq_params;
	wq_params[0].type = ACPI_TYPE_INTEGER;
	wq_params[0].integer.value = instance;

	if (instance == 0 && wblock->read_takes_no_args)
		input.count = 0;

	/*
	 * If ACPI_WMI_EXPENSIVE, call the relevant WCxx method first to
	 * enable collection.
	 */
	if (block->flags & ACPI_WMI_EXPENSIVE) {
		strncat(wc_method, block->object_id, 2);

		/*
		 * Some GUIDs break the specification by declaring themselves
		 * expensive, but have no corresponding WCxx method. So we
		 * should not fail if this happens.
		 */
		wc_status = acpi_execute_simple_method(handle, wc_method, 1);
	}

	strcpy(method, "WQ");
	strncat(method, block->object_id, 2);

	status = acpi_evaluate_object(handle, method, &input, out);

	/*
	 * If ACPI_WMI_EXPENSIVE, call the relevant WCxx method, even if
	 * the WQxx method failed - we should disable collection anyway.
	 */
	if ((block->flags & ACPI_WMI_EXPENSIVE) && ACPI_SUCCESS(wc_status)) {
		status = acpi_execute_simple_method(handle, wc_method, 0);
	}

	return status;
}

/**
 * wmi_query_block - Return contents of a WMI block (deprecated)
 * @guid_string: 36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
 * @instance: Instance index
 * @out: Empty buffer to return the contents of the data block to
 *
 * Return the contents of an ACPI-WMI data block to a buffer
 */
acpi_status wmi_query_block(const char *guid_string, u8 instance,
			    struct acpi_buffer *out)
{
	struct wmi_block *wblock;

	if (!guid_string)
		return AE_BAD_PARAMETER;

	if (!find_guid(guid_string, &wblock))
		return AE_ERROR;

	return __query_block(wblock, instance, out);
}
EXPORT_SYMBOL_GPL(wmi_query_block);

union acpi_object *wmidev_block_query(struct wmi_device *wdev, u8 instance)
{
	struct acpi_buffer out = { ACPI_ALLOCATE_BUFFER, NULL };
	struct wmi_block *wblock = container_of(wdev, struct wmi_block, dev);

	if (ACPI_FAILURE(__query_block(wblock, instance, &out)))
		return NULL;

	return (union acpi_object *)out.pointer;
}
EXPORT_SYMBOL_GPL(wmidev_block_query);

/**
 * wmi_set_block - Write to a WMI block
 * @guid_string: 36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
 * @instance: Instance index
 * @in: Buffer containing new values for the data block
 *
 * Write the contents of the input buffer to an ACPI-WMI data block
 */
acpi_status wmi_set_block(const char *guid_string, u8 instance,
			  const struct acpi_buffer *in)
{
	struct guid_block *block = NULL;
	struct wmi_block *wblock = NULL;
	acpi_handle handle;
	struct acpi_object_list input;
	union acpi_object params[2];
	char method[5] = "WS";

	if (!guid_string || !in)
		return AE_BAD_DATA;

	if (!find_guid(guid_string, &wblock))
		return AE_ERROR;

	block = &wblock->gblock;
	handle = wblock->acpi_device->handle;

	if (block->instance_count <= instance)
		return AE_BAD_PARAMETER;

	/* Check GUID is a data block */
	if (block->flags & (ACPI_WMI_EVENT | ACPI_WMI_METHOD))
		return AE_ERROR;

	input.count = 2;
	input.pointer = params;
	params[0].type = ACPI_TYPE_INTEGER;
	params[0].integer.value = instance;

	if (block->flags & ACPI_WMI_STRING) {
		params[1].type = ACPI_TYPE_STRING;
	} else {
		params[1].type = ACPI_TYPE_BUFFER;
	}
	params[1].buffer.length = in->length;
	params[1].buffer.pointer = in->pointer;

	strncat(method, block->object_id, 2);

	return acpi_evaluate_object(handle, method, &input, NULL);
}
EXPORT_SYMBOL_GPL(wmi_set_block);

static void wmi_dump_wdg(const struct guid_block *g)
{
	pr_info("%pUL:\n", g->guid);
	if (g->flags & ACPI_WMI_EVENT)
		pr_info("\tnotify_id: 0x%02X\n", g->notify_id);
	else
		pr_info("\tobject_id: %2pE\n", g->object_id);
	pr_info("\tinstance_count: %d\n", g->instance_count);
	pr_info("\tflags: %#x", g->flags);
	if (g->flags) {
		if (g->flags & ACPI_WMI_EXPENSIVE)
			pr_cont(" ACPI_WMI_EXPENSIVE");
		if (g->flags & ACPI_WMI_METHOD)
			pr_cont(" ACPI_WMI_METHOD");
		if (g->flags & ACPI_WMI_STRING)
			pr_cont(" ACPI_WMI_STRING");
		if (g->flags & ACPI_WMI_EVENT)
			pr_cont(" ACPI_WMI_EVENT");
	}
	pr_cont("\n");

}

static void wmi_notify_debug(u32 value, void *context)
{
	struct acpi_buffer response = { ACPI_ALLOCATE_BUFFER, NULL };
	union acpi_object *obj;
	acpi_status status;

	status = wmi_get_event_data(value, &response);
	if (status != AE_OK) {
		pr_info("bad event status 0x%x\n", status);
		return;
	}

	obj = (union acpi_object *)response.pointer;

	if (!obj)
		return;

	pr_info("DEBUG Event ");
	switch(obj->type) {
	case ACPI_TYPE_BUFFER:
		pr_cont("BUFFER_TYPE - length %d\n", obj->buffer.length);
		break;
	case ACPI_TYPE_STRING:
		pr_cont("STRING_TYPE - %s\n", obj->string.pointer);
		break;
	case ACPI_TYPE_INTEGER:
		pr_cont("INTEGER_TYPE - %llu\n", obj->integer.value);
		break;
	case ACPI_TYPE_PACKAGE:
		pr_cont("PACKAGE_TYPE - %d elements\n", obj->package.count);
		break;
	default:
		pr_cont("object type 0x%X\n", obj->type);
	}
	kfree(obj);
}

/**
 * wmi_install_notify_handler - Register handler for WMI events
 * @guid: 36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
 * @handler: Function to handle notifications
 * @data: Data to be returned to handler when event is fired
 *
 * Register a handler for events sent to the ACPI-WMI mapper device.
 */
acpi_status wmi_install_notify_handler(const char *guid,
wmi_notify_handler handler, void *data)
{
	struct wmi_block *block;
	acpi_status status = AE_NOT_EXIST;
	guid_t guid_input;

	if (!guid || !handler)
		return AE_BAD_PARAMETER;

	if (guid_parse(guid, &guid_input))
		return AE_BAD_PARAMETER;

	list_for_each_entry(block, &wmi_block_list, list) {
		acpi_status wmi_status;

		if (memcmp(block->gblock.guid, &guid_input, 16) == 0) {
			if (block->handler &&
			    block->handler != wmi_notify_debug)
				return AE_ALREADY_ACQUIRED;

			block->handler = handler;
			block->handler_data = data;

			wmi_status = wmi_method_enable(block, 1);
			if ((wmi_status != AE_OK) ||
			    ((wmi_status == AE_OK) && (status == AE_NOT_EXIST)))
				status = wmi_status;
		}
	}

	return status;
}
EXPORT_SYMBOL_GPL(wmi_install_notify_handler);

/**
 * wmi_uninstall_notify_handler - Unregister handler for WMI events
 * @guid: 36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
 *
 * Unregister handler for events sent to the ACPI-WMI mapper device.
 */
acpi_status wmi_remove_notify_handler(const char *guid)
{
	struct wmi_block *block;
	acpi_status status = AE_NOT_EXIST;
	guid_t guid_input;

	if (!guid)
		return AE_BAD_PARAMETER;

	if (guid_parse(guid, &guid_input))
		return AE_BAD_PARAMETER;

	list_for_each_entry(block, &wmi_block_list, list) {
		acpi_status wmi_status;

		if (memcmp(block->gblock.guid, &guid_input, 16) == 0) {
			if (!block->handler ||
			    block->handler == wmi_notify_debug)
				return AE_NULL_ENTRY;

			if (debug_event) {
				block->handler = wmi_notify_debug;
				status = AE_OK;
			} else {
				wmi_status = wmi_method_enable(block, 0);
				block->handler = NULL;
				block->handler_data = NULL;
				if ((wmi_status != AE_OK) ||
				    ((wmi_status == AE_OK) &&
				     (status == AE_NOT_EXIST)))
					status = wmi_status;
			}
		}
	}

	return status;
}
EXPORT_SYMBOL_GPL(wmi_remove_notify_handler);

/**
 * wmi_get_event_data - Get WMI data associated with an event
 *
 * @event: Event to find
 * @out: Buffer to hold event data. out->pointer should be freed with kfree()
 *
 * Returns extra data associated with an event in WMI.
 */
acpi_status wmi_get_event_data(u32 event, struct acpi_buffer *out)
{
	struct acpi_object_list input;
	union acpi_object params[1];
	struct guid_block *gblock;
	struct wmi_block *wblock;

	input.count = 1;
	input.pointer = params;
	params[0].type = ACPI_TYPE_INTEGER;
	params[0].integer.value = event;

	list_for_each_entry(wblock, &wmi_block_list, list) {
		gblock = &wblock->gblock;

		if ((gblock->flags & ACPI_WMI_EVENT) &&
			(gblock->notify_id == event))
			return acpi_evaluate_object(wblock->acpi_device->handle,
				"_WED", &input, out);
	}

	return AE_NOT_FOUND;
}
EXPORT_SYMBOL_GPL(wmi_get_event_data);

/**
 * wmi_has_guid - Check if a GUID is available
 * @guid_string: 36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
 *
 * Check if a given GUID is defined by _WDG
 */
bool wmi_has_guid(const char *guid_string)
{
	return find_guid(guid_string, NULL);
}
EXPORT_SYMBOL_GPL(wmi_has_guid);

/**
 * wmi_get_acpi_device_uid() - Get _UID name of ACPI device that defines GUID
 * @guid_string: 36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
 *
 * Find the _UID of ACPI device associated with this WMI GUID.
 *
 * Return: The ACPI _UID field value or NULL if the WMI GUID was not found
 */
char *wmi_get_acpi_device_uid(const char *guid_string)
{
	struct wmi_block *wblock = NULL;

	if (!find_guid(guid_string, &wblock))
		return NULL;

	return acpi_device_uid(wblock->acpi_device);
}
EXPORT_SYMBOL_GPL(wmi_get_acpi_device_uid);

static struct wmi_block *dev_to_wblock(struct device *dev)
{
	return container_of(dev, struct wmi_block, dev.dev);
}

static struct wmi_device *dev_to_wdev(struct device *dev)
{
	return container_of(dev, struct wmi_device, dev);
}

/*
 * sysfs interface
 */
static ssize_t modalias_show(struct device *dev, struct device_attribute *attr,
			     char *buf)
{
	struct wmi_block *wblock = dev_to_wblock(dev);

	return sprintf(buf, "wmi:%pUL\n", wblock->gblock.guid);
}
static DEVICE_ATTR_RO(modalias);

static ssize_t guid_show(struct device *dev, struct device_attribute *attr,
			 char *buf)
{
	struct wmi_block *wblock = dev_to_wblock(dev);

	return sprintf(buf, "%pUL\n", wblock->gblock.guid);
}
static DEVICE_ATTR_RO(guid);

static ssize_t instance_count_show(struct device *dev,
				   struct device_attribute *attr, char *buf)
{
	struct wmi_block *wblock = dev_to_wblock(dev);

	return sprintf(buf, "%d\n", (int)wblock->gblock.instance_count);
}
static DEVICE_ATTR_RO(instance_count);

static ssize_t expensive_show(struct device *dev,
			      struct device_attribute *attr, char *buf)
{
	struct wmi_block *wblock = dev_to_wblock(dev);

	return sprintf(buf, "%d\n",
		       (wblock->gblock.flags & ACPI_WMI_EXPENSIVE) != 0);
}
static DEVICE_ATTR_RO(expensive);

static struct attribute *wmi_attrs[] = {
	&dev_attr_modalias.attr,
	&dev_attr_guid.attr,
	&dev_attr_instance_count.attr,
	&dev_attr_expensive.attr,
	NULL,
};
ATTRIBUTE_GROUPS(wmi);

static ssize_t notify_id_show(struct device *dev, struct device_attribute *attr,
			      char *buf)
{
	struct wmi_block *wblock = dev_to_wblock(dev);

	return sprintf(buf, "%02X\n", (unsigned int)wblock->gblock.notify_id);
}
static DEVICE_ATTR_RO(notify_id);

static struct attribute *wmi_event_attrs[] = {
	&dev_attr_notify_id.attr,
	NULL,
};
ATTRIBUTE_GROUPS(wmi_event);

static ssize_t object_id_show(struct device *dev, struct device_attribute *attr,
			      char *buf)
{
	struct wmi_block *wblock = dev_to_wblock(dev);

	return sprintf(buf, "%c%c\n", wblock->gblock.object_id[0],
		       wblock->gblock.object_id[1]);
}
static DEVICE_ATTR_RO(object_id);

static ssize_t setable_show(struct device *dev, struct device_attribute *attr,
			    char *buf)
{
	struct wmi_device *wdev = dev_to_wdev(dev);

	return sprintf(buf, "%d\n", (int)wdev->setable);
}
static DEVICE_ATTR_RO(setable);

static struct attribute *wmi_data_attrs[] = {
	&dev_attr_object_id.attr,
	&dev_attr_setable.attr,
	NULL,
};
ATTRIBUTE_GROUPS(wmi_data);

static struct attribute *wmi_method_attrs[] = {
	&dev_attr_object_id.attr,
	NULL,
};
ATTRIBUTE_GROUPS(wmi_method);

static int wmi_dev_uevent(struct device *dev, struct kobj_uevent_env *env)
{
	struct wmi_block *wblock = dev_to_wblock(dev);

	if (add_uevent_var(env, "MODALIAS=wmi:%pUL", wblock->gblock.guid))
		return -ENOMEM;

	if (add_uevent_var(env, "WMI_GUID=%pUL", wblock->gblock.guid))
		return -ENOMEM;

	return 0;
}

static void wmi_dev_release(struct device *dev)
{
	struct wmi_block *wblock = dev_to_wblock(dev);

	kfree(wblock);
}

static int wmi_dev_match(struct device *dev, struct device_driver *driver)
{
	struct wmi_driver *wmi_driver =
		container_of(driver, struct wmi_driver, driver);
	struct wmi_block *wblock = dev_to_wblock(dev);
	const struct wmi_device_id *id = wmi_driver->id_table;

	if (id == NULL)
		return 0;

	while (*id->guid_string) {
		guid_t driver_guid;

		if (WARN_ON(guid_parse(id->guid_string, &driver_guid)))
			continue;
		if (!memcmp(&driver_guid, wblock->gblock.guid, 16))
			return 1;

		id++;
	}

	return 0;
}
static int wmi_char_open(struct inode *inode, struct file *filp)
{
	const char *driver_name = filp->f_path.dentry->d_iname;
	struct wmi_block *wblock = NULL;
	struct wmi_block *next = NULL;

	list_for_each_entry_safe(wblock, next, &wmi_block_list, list) {
		if (!wblock->dev.dev.driver)
			continue;
		if (strcmp(driver_name, wblock->dev.dev.driver->name) == 0) {
			filp->private_data = wblock;
			break;
		}
	}

	if (!filp->private_data)
		return -ENODEV;

	return nonseekable_open(inode, filp);
}

static ssize_t wmi_char_read(struct file *filp, char __user *buffer,
	size_t length, loff_t *offset)
{
	struct wmi_block *wblock = filp->private_data;

	return simple_read_from_buffer(buffer, length, offset,
				       &wblock->req_buf_size,
				       sizeof(wblock->req_buf_size));
}

static long wmi_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
{
	struct wmi_ioctl_buffer __user *input =
		(struct wmi_ioctl_buffer __user *) arg;
	struct wmi_block *wblock = filp->private_data;
	struct wmi_ioctl_buffer *buf = NULL;
	struct wmi_driver *wdriver = NULL;
	int ret;

	if (_IOC_TYPE(cmd) != WMI_IOC)
		return -ENOTTY;

	/* make sure we're not calling a higher instance than exists*/
	if (_IOC_NR(cmd) >= wblock->gblock.instance_count)
		return -EINVAL;

	mutex_lock(&wblock->char_mutex);
	buf = wblock->handler_data;
	if (get_user(buf->length, &input->length)) {
		dev_dbg(&wblock->dev.dev, "Read length from user failed\n");
		ret = -EFAULT;
		goto out_ioctl;
	}
	/* if it's too small, abort */
	if (buf->length < wblock->req_buf_size) {
		dev_err(&wblock->dev.dev,
			"Buffer %lld too small, need at least %lld\n",
			buf->length, wblock->req_buf_size);
		ret = -EINVAL;
		goto out_ioctl;
	}
	/* if it's too big, warn, driver will only use what is needed */
	if (buf->length > wblock->req_buf_size)
		dev_warn(&wblock->dev.dev,
			"Buffer %lld is bigger than required %lld\n",
			buf->length, wblock->req_buf_size);

	/* copy the structure from userspace */
	if (copy_from_user(buf, input, wblock->req_buf_size)) {
		dev_dbg(&wblock->dev.dev, "Copy %llu from user failed\n",
			wblock->req_buf_size);
		ret = -EFAULT;
		goto out_ioctl;
	}

	/* let the driver do any filtering and do the call */
	wdriver = container_of(wblock->dev.dev.driver,
			       struct wmi_driver, driver);
	if (!try_module_get(wdriver->driver.owner)) {
		ret = -EBUSY;
		goto out_ioctl;
	}
	ret = wdriver->filter_callback(&wblock->dev, cmd, buf);
	module_put(wdriver->driver.owner);
	if (ret)
		goto out_ioctl;

	/* return the result (only up to our internal buffer size) */
	if (copy_to_user(input, buf, wblock->req_buf_size)) {
		dev_dbg(&wblock->dev.dev, "Copy %llu to user failed\n",
			wblock->req_buf_size);
		ret = -EFAULT;
	}

out_ioctl:
	mutex_unlock(&wblock->char_mutex);
	return ret;
}

static const struct file_operations wmi_fops = {
	.owner		= THIS_MODULE,
	.read		= wmi_char_read,
	.open		= wmi_char_open,
	.unlocked_ioctl	= wmi_ioctl,
	.compat_ioctl	= compat_ptr_ioctl,
};

static int wmi_dev_probe(struct device *dev)
{
	struct wmi_block *wblock = dev_to_wblock(dev);
	struct wmi_driver *wdriver =
		container_of(dev->driver, struct wmi_driver, driver);
	int ret = 0;
	char *buf;

	if (ACPI_FAILURE(wmi_method_enable(wblock, 1)))
		dev_warn(dev, "failed to enable device -- probing anyway\n");

	if (wdriver->probe) {
		ret = wdriver->probe(dev_to_wdev(dev),
				find_guid_context(wblock, wdriver));
		if (ret != 0)
			goto probe_failure;
	}

	/* driver wants a character device made */
	if (wdriver->filter_callback) {
		/* check that required buffer size declared by driver or MOF */
		if (!wblock->req_buf_size) {
			dev_err(&wblock->dev.dev,
				"Required buffer size not set\n");
			ret = -EINVAL;
			goto probe_failure;
		}

		wblock->handler_data = kmalloc(wblock->req_buf_size,
					       GFP_KERNEL);
		if (!wblock->handler_data) {
			ret = -ENOMEM;
			goto probe_failure;
		}

		buf = kasprintf(GFP_KERNEL, "wmi/%s", wdriver->driver.name);
		if (!buf) {
			ret = -ENOMEM;
			goto probe_string_failure;
		}
		wblock->char_dev.minor = MISC_DYNAMIC_MINOR;
		wblock->char_dev.name = buf;
		wblock->char_dev.fops = &wmi_fops;
		wblock->char_dev.mode = 0444;
		ret = misc_register(&wblock->char_dev);
		if (ret) {
			dev_warn(dev, "failed to register char dev: %d\n", ret);
			ret = -ENOMEM;
			goto probe_misc_failure;
		}
	}

	return 0;

probe_misc_failure:
	kfree(buf);
probe_string_failure:
	kfree(wblock->handler_data);
probe_failure:
	if (ACPI_FAILURE(wmi_method_enable(wblock, 0)))
		dev_warn(dev, "failed to disable device\n");
	return ret;
}

static int wmi_dev_remove(struct device *dev)
{
	struct wmi_block *wblock = dev_to_wblock(dev);
	struct wmi_driver *wdriver =
		container_of(dev->driver, struct wmi_driver, driver);
	int ret = 0;

	if (wdriver->filter_callback) {
		misc_deregister(&wblock->char_dev);
		kfree(wblock->char_dev.name);
		kfree(wblock->handler_data);
	}

	if (wdriver->remove)
		ret = wdriver->remove(dev_to_wdev(dev));

	if (ACPI_FAILURE(wmi_method_enable(wblock, 0)))
		dev_warn(dev, "failed to disable device\n");

	return ret;
}

static struct class wmi_bus_class = {
	.name = "wmi_bus",
};

static struct bus_type wmi_bus_type = {
	.name = "wmi",
	.dev_groups = wmi_groups,
	.match = wmi_dev_match,
	.uevent = wmi_dev_uevent,
	.probe = wmi_dev_probe,
	.remove = wmi_dev_remove,
};

static const struct device_type wmi_type_event = {
	.name = "event",
	.groups = wmi_event_groups,
	.release = wmi_dev_release,
};

static const struct device_type wmi_type_method = {
	.name = "method",
	.groups = wmi_method_groups,
	.release = wmi_dev_release,
};

static const struct device_type wmi_type_data = {
	.name = "data",
	.groups = wmi_data_groups,
	.release = wmi_dev_release,
};

static int wmi_create_device(struct device *wmi_bus_dev,
			     const struct guid_block *gblock,
			     struct wmi_block *wblock,
			     struct acpi_device *device)
{
	struct acpi_device_info *info;
	char method[5];
	int result;

	if (gblock->flags & ACPI_WMI_EVENT) {
		wblock->dev.dev.type = &wmi_type_event;
		goto out_init;
	}

	if (gblock->flags & ACPI_WMI_METHOD) {
		wblock->dev.dev.type = &wmi_type_method;
		mutex_init(&wblock->char_mutex);
		goto out_init;
	}

	/*
	 * Data Block Query Control Method (WQxx by convention) is
	 * required per the WMI documentation. If it is not present,
	 * we ignore this data block.
	 */
	strcpy(method, "WQ");
	strncat(method, wblock->gblock.object_id, 2);
	result = get_subobj_info(device->handle, method, &info);

	if (result) {
		dev_warn(wmi_bus_dev,
			 "%s data block query control method not found\n",
			 method);
		return result;
	}

	wblock->dev.dev.type = &wmi_type_data;

	/*
	 * The Microsoft documentation specifically states:
	 *
	 *   Data blocks registered with only a single instance
	 *   can ignore the parameter.
	 *
	 * ACPICA will get mad at us if we call the method with the wrong number
	 * of arguments, so check what our method expects.  (On some Dell
	 * laptops, WQxx may not be a method at all.)
	 */
	if (info->type != ACPI_TYPE_METHOD || info->param_count == 0)
		wblock->read_takes_no_args = true;

	kfree(info);

	strcpy(method, "WS");
	strncat(method, wblock->gblock.object_id, 2);
	result = get_subobj_info(device->handle, method, NULL);

	if (result == 0)
		wblock->dev.setable = true;

 out_init:
	wblock->dev.dev.bus = &wmi_bus_type;
	wblock->dev.dev.parent = wmi_bus_dev;

	dev_set_name(&wblock->dev.dev, "%pUL", gblock->guid);

	device_initialize(&wblock->dev.dev);

	return 0;
}

static void wmi_free_devices(struct acpi_device *device)
{
	struct wmi_block *wblock, *next;

	/* Delete devices for all the GUIDs */
	list_for_each_entry_safe(wblock, next, &wmi_block_list, list) {
		if (wblock->acpi_device == device) {
			list_del(&wblock->list);
			device_unregister(&wblock->dev.dev);
		}
	}
}

static bool guid_already_parsed(struct acpi_device *device, const u8 *guid)
{
	struct wmi_block *wblock;

	list_for_each_entry(wblock, &wmi_block_list, list) {
		if (memcmp(wblock->gblock.guid, guid, 16) == 0) {
			/*
			 * Because we historically didn't track the relationship
			 * between GUIDs and ACPI nodes, we don't know whether
			 * we need to suppress GUIDs that are unique on a
			 * given node but duplicated across nodes.
			 */
			dev_warn(&device->dev, "duplicate WMI GUID %pUL (first instance was on %s)\n",
				 guid, dev_name(&wblock->acpi_device->dev));
			return true;
		}
	}

	return false;
}

/*
 * Parse the _WDG method for the GUID data blocks
 */
static int parse_wdg(struct device *wmi_bus_dev, struct acpi_device *device)
{
	struct acpi_buffer out = {ACPI_ALLOCATE_BUFFER, NULL};
	const struct guid_block *gblock;
	struct wmi_block *wblock, *next;
	union acpi_object *obj;
	acpi_status status;
	int retval = 0;
	u32 i, total;

	status = acpi_evaluate_object(device->handle, "_WDG", NULL, &out);
	if (ACPI_FAILURE(status))
		return -ENXIO;

	obj = (union acpi_object *) out.pointer;
	if (!obj)
		return -ENXIO;

	if (obj->type != ACPI_TYPE_BUFFER) {
		retval = -ENXIO;
		goto out_free_pointer;
	}

	gblock = (const struct guid_block *)obj->buffer.pointer;
	total = obj->buffer.length / sizeof(struct guid_block);

	for (i = 0; i < total; i++) {
		if (debug_dump_wdg)
			wmi_dump_wdg(&gblock[i]);

		/*
		 * Some WMI devices, like those for nVidia hooks, have a
		 * duplicate GUID. It's not clear what we should do in this
		 * case yet, so for now, we'll just ignore the duplicate
		 * for device creation.
		 */
		if (guid_already_parsed(device, gblock[i].guid))
			continue;

		wblock = kzalloc(sizeof(struct wmi_block), GFP_KERNEL);
		if (!wblock) {
			retval = -ENOMEM;
			break;
		}

		wblock->acpi_device = device;
		wblock->gblock = gblock[i];

		retval = wmi_create_device(wmi_bus_dev, &gblock[i], wblock, device);
		if (retval) {
			kfree(wblock);
			continue;
		}

		list_add_tail(&wblock->list, &wmi_block_list);

		if (debug_event) {
			wblock->handler = wmi_notify_debug;
			wmi_method_enable(wblock, 1);
		}
	}

	/*
	 * Now that all of the devices are created, add them to the
	 * device tree and probe subdrivers.
	 */
	list_for_each_entry_safe(wblock, next, &wmi_block_list, list) {
		if (wblock->acpi_device != device)
			continue;

		retval = device_add(&wblock->dev.dev);
		if (retval) {
			dev_err(wmi_bus_dev, "failed to register %pUL\n",
				wblock->gblock.guid);
			if (debug_event)
				wmi_method_enable(wblock, 0);
			list_del(&wblock->list);
			put_device(&wblock->dev.dev);
		}
	}

out_free_pointer:
	kfree(out.pointer);
	return retval;
}

/*
 * WMI can have EmbeddedControl access regions. In which case, we just want to
 * hand these off to the EC driver.
 */
static acpi_status
acpi_wmi_ec_space_handler(u32 function, acpi_physical_address address,
		      u32 bits, u64 *value,
		      void *handler_context, void *region_context)
{
	int result = 0, i = 0;
	u8 temp = 0;

	if ((address > 0xFF) || !value)
		return AE_BAD_PARAMETER;

	if (function != ACPI_READ && function != ACPI_WRITE)
		return AE_BAD_PARAMETER;

	if (bits != 8)
		return AE_BAD_PARAMETER;

	if (function == ACPI_READ) {
		result = ec_read(address, &temp);
		(*value) |= ((u64)temp) << i;
	} else {
		temp = 0xff & ((*value) >> i);
		result = ec_write(address, temp);
	}

	switch (result) {
	case -EINVAL:
		return AE_BAD_PARAMETER;
	case -ENODEV:
		return AE_NOT_FOUND;
	case -ETIME:
		return AE_TIME;
	default:
		return AE_OK;
	}
}

static void acpi_wmi_notify_handler(acpi_handle handle, u32 event,
				    void *context)
{
	struct guid_block *block;
	struct wmi_block *wblock;
	bool found_it = false;

	list_for_each_entry(wblock, &wmi_block_list, list) {
		block = &wblock->gblock;

		if (wblock->acpi_device->handle == handle &&
		    (block->flags & ACPI_WMI_EVENT) &&
		    (block->notify_id == event))
		{
			found_it = true;
			break;
		}
	}

	if (!found_it)
		return;

	/* If a driver is bound, then notify the driver. */
	if (wblock->dev.dev.driver) {
		struct wmi_driver *driver;
		struct acpi_object_list input;
		union acpi_object params[1];
		struct acpi_buffer evdata = { ACPI_ALLOCATE_BUFFER, NULL };
		acpi_status status;

		driver = container_of(wblock->dev.dev.driver,
				      struct wmi_driver, driver);

		input.count = 1;
		input.pointer = params;
		params[0].type = ACPI_TYPE_INTEGER;
		params[0].integer.value = event;

		status = acpi_evaluate_object(wblock->acpi_device->handle,
					      "_WED", &input, &evdata);
		if (ACPI_FAILURE(status)) {
			dev_warn(&wblock->dev.dev,
				 "failed to get event data\n");
			return;
		}

		if (driver->notify)
			driver->notify(&wblock->dev,
				       (union acpi_object *)evdata.pointer);

		kfree(evdata.pointer);
	} else if (wblock->handler) {
		/* Legacy handler */
		wblock->handler(event, wblock->handler_data);
	}

	if (debug_event)
		pr_info("DEBUG Event GUID: %pUL\n", wblock->gblock.guid);

	acpi_bus_generate_netlink_event(
		wblock->acpi_device->pnp.device_class,
		dev_name(&wblock->dev.dev),
		event, 0);

}

static int acpi_wmi_remove(struct platform_device *device)
{
	struct acpi_device *acpi_device = ACPI_COMPANION(&device->dev);

	acpi_remove_notify_handler(acpi_device->handle, ACPI_DEVICE_NOTIFY,
				   acpi_wmi_notify_handler);
	acpi_remove_address_space_handler(acpi_device->handle,
				ACPI_ADR_SPACE_EC, &acpi_wmi_ec_space_handler);
	wmi_free_devices(acpi_device);
	device_unregister((struct device *)dev_get_drvdata(&device->dev));

	return 0;
}

static int acpi_wmi_probe(struct platform_device *device)
{
	struct acpi_device *acpi_device;
	struct device *wmi_bus_dev;
	acpi_status status;
	int error;

	acpi_device = ACPI_COMPANION(&device->dev);
	if (!acpi_device) {
		dev_err(&device->dev, "ACPI companion is missing\n");
		return -ENODEV;
	}

	status = acpi_install_address_space_handler(acpi_device->handle,
						    ACPI_ADR_SPACE_EC,
						    &acpi_wmi_ec_space_handler,
						    NULL, NULL);
	if (ACPI_FAILURE(status)) {
		dev_err(&device->dev, "Error installing EC region handler\n");
		return -ENODEV;
	}

	status = acpi_install_notify_handler(acpi_device->handle,
					     ACPI_DEVICE_NOTIFY,
					     acpi_wmi_notify_handler,
					     NULL);
	if (ACPI_FAILURE(status)) {
		dev_err(&device->dev, "Error installing notify handler\n");
		error = -ENODEV;
		goto err_remove_ec_handler;
	}

	wmi_bus_dev = device_create(&wmi_bus_class, &device->dev, MKDEV(0, 0),
				    NULL, "wmi_bus-%s", dev_name(&device->dev));
	if (IS_ERR(wmi_bus_dev)) {
		error = PTR_ERR(wmi_bus_dev);
		goto err_remove_notify_handler;
	}
	dev_set_drvdata(&device->dev, wmi_bus_dev);

	error = parse_wdg(wmi_bus_dev, acpi_device);
	if (error) {
		pr_err("Failed to parse WDG method\n");
		goto err_remove_busdev;
	}

	return 0;

err_remove_busdev:
	device_unregister(wmi_bus_dev);

err_remove_notify_handler:
	acpi_remove_notify_handler(acpi_device->handle, ACPI_DEVICE_NOTIFY,
				   acpi_wmi_notify_handler);

err_remove_ec_handler:
	acpi_remove_address_space_handler(acpi_device->handle,
					  ACPI_ADR_SPACE_EC,
					  &acpi_wmi_ec_space_handler);

	return error;
}

int __must_check __wmi_driver_register(struct wmi_driver *driver,
				       struct module *owner)
{
	driver->driver.owner = owner;
	driver->driver.bus = &wmi_bus_type;

	return driver_register(&driver->driver);
}
EXPORT_SYMBOL(__wmi_driver_register);

void wmi_driver_unregister(struct wmi_driver *driver)
{
	driver_unregister(&driver->driver);
}
EXPORT_SYMBOL(wmi_driver_unregister);

static int __init acpi_wmi_init(void)
{
	int error;

	if (acpi_disabled)
		return -ENODEV;

	error = class_register(&wmi_bus_class);
	if (error)
		return error;

	error = bus_register(&wmi_bus_type);
	if (error)
		goto err_unreg_class;

	error = platform_driver_register(&acpi_wmi_driver);
	if (error) {
		pr_err("Error loading mapper\n");
		goto err_unreg_bus;
	}

	return 0;

err_unreg_bus:
	bus_unregister(&wmi_bus_type);

err_unreg_class:
	class_unregister(&wmi_bus_class);

	return error;
}

static void __exit acpi_wmi_exit(void)
{
	platform_driver_unregister(&acpi_wmi_driver);
	bus_unregister(&wmi_bus_type);
	class_unregister(&wmi_bus_class);
}

subsys_initcall_sync(acpi_wmi_init);
module_exit(acpi_wmi_exit);