summaryrefslogtreecommitdiffstats
path: root/drivers/acpi/utils.c
blob: e7ddd281afff7f6ed9964c52e042e8d8393cf89a (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
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *  acpi_utils.c - ACPI Utility Functions ($Revision: 10 $)
 *
 *  Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
 *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
 */

#define pr_fmt(fmt) "ACPI: utils: " fmt

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/hardirq.h>
#include <linux/acpi.h>
#include <linux/dynamic_debug.h>

#include "internal.h"
#include "sleep.h"

/* --------------------------------------------------------------------------
                            Object Evaluation Helpers
   -------------------------------------------------------------------------- */
static void acpi_util_eval_error(acpi_handle h, acpi_string p, acpi_status s)
{
	acpi_handle_debug(h, "Evaluate [%s]: %s\n", p, acpi_format_exception(s));
}

acpi_status
acpi_extract_package(union acpi_object *package,
		     struct acpi_buffer *format, struct acpi_buffer *buffer)
{
	u32 size_required = 0;
	u32 tail_offset = 0;
	char *format_string = NULL;
	u32 format_count = 0;
	u32 i = 0;
	u8 *head = NULL;
	u8 *tail = NULL;


	if (!package || (package->type != ACPI_TYPE_PACKAGE)
	    || (package->package.count < 1)) {
		pr_debug("Invalid package argument\n");
		return AE_BAD_PARAMETER;
	}

	if (!format || !format->pointer || (format->length < 1)) {
		pr_debug("Invalid format argument\n");
		return AE_BAD_PARAMETER;
	}

	if (!buffer) {
		pr_debug("Invalid buffer argument\n");
		return AE_BAD_PARAMETER;
	}

	format_count = (format->length / sizeof(char)) - 1;
	if (format_count > package->package.count) {
		pr_debug("Format specifies more objects [%d] than present [%d]\n",
			 format_count, package->package.count);
		return AE_BAD_DATA;
	}

	format_string = format->pointer;

	/*
	 * Calculate size_required.
	 */
	for (i = 0; i < format_count; i++) {

		union acpi_object *element = &(package->package.elements[i]);

		switch (element->type) {

		case ACPI_TYPE_INTEGER:
			switch (format_string[i]) {
			case 'N':
				size_required += sizeof(u64);
				tail_offset += sizeof(u64);
				break;
			case 'S':
				size_required +=
				    sizeof(char *) + sizeof(u64) +
				    sizeof(char);
				tail_offset += sizeof(char *);
				break;
			default:
				pr_debug("Invalid package element [%d]: got number, expected [%c]\n",
					 i, format_string[i]);
				return AE_BAD_DATA;
			}
			break;

		case ACPI_TYPE_STRING:
		case ACPI_TYPE_BUFFER:
			switch (format_string[i]) {
			case 'S':
				size_required +=
				    sizeof(char *) +
				    (element->string.length * sizeof(char)) +
				    sizeof(char);
				tail_offset += sizeof(char *);
				break;
			case 'B':
				size_required +=
				    sizeof(u8 *) + element->buffer.length;
				tail_offset += sizeof(u8 *);
				break;
			default:
				pr_debug("Invalid package element [%d] got string/buffer, expected [%c]\n",
					 i, format_string[i]);
				return AE_BAD_DATA;
			}
			break;
		case ACPI_TYPE_LOCAL_REFERENCE:
			switch (format_string[i]) {
			case 'R':
				size_required += sizeof(void *);
				tail_offset += sizeof(void *);
				break;
			default:
				pr_debug("Invalid package element [%d] got reference, expected [%c]\n",
					 i, format_string[i]);
				return AE_BAD_DATA;
			}
			break;

		case ACPI_TYPE_PACKAGE:
		default:
			pr_debug("Unsupported element at index=%d\n", i);
			/* TBD: handle nested packages... */
			return AE_SUPPORT;
		}
	}

	/*
	 * Validate output buffer.
	 */
	if (buffer->length == ACPI_ALLOCATE_BUFFER) {
		buffer->pointer = ACPI_ALLOCATE_ZEROED(size_required);
		if (!buffer->pointer)
			return AE_NO_MEMORY;
		buffer->length = size_required;
	} else {
		if (buffer->length < size_required) {
			buffer->length = size_required;
			return AE_BUFFER_OVERFLOW;
		} else if (buffer->length != size_required ||
			   !buffer->pointer) {
			return AE_BAD_PARAMETER;
		}
	}

	head = buffer->pointer;
	tail = buffer->pointer + tail_offset;

	/*
	 * Extract package data.
	 */
	for (i = 0; i < format_count; i++) {

		u8 **pointer = NULL;
		union acpi_object *element = &(package->package.elements[i]);

		switch (element->type) {

		case ACPI_TYPE_INTEGER:
			switch (format_string[i]) {
			case 'N':
				*((u64 *) head) =
				    element->integer.value;
				head += sizeof(u64);
				break;
			case 'S':
				pointer = (u8 **) head;
				*pointer = tail;
				*((u64 *) tail) =
				    element->integer.value;
				head += sizeof(u64 *);
				tail += sizeof(u64);
				/* NULL terminate string */
				*tail = (char)0;
				tail += sizeof(char);
				break;
			default:
				/* Should never get here */
				break;
			}
			break;

		case ACPI_TYPE_STRING:
		case ACPI_TYPE_BUFFER:
			switch (format_string[i]) {
			case 'S':
				pointer = (u8 **) head;
				*pointer = tail;
				memcpy(tail, element->string.pointer,
				       element->string.length);
				head += sizeof(char *);
				tail += element->string.length * sizeof(char);
				/* NULL terminate string */
				*tail = (char)0;
				tail += sizeof(char);
				break;
			case 'B':
				pointer = (u8 **) head;
				*pointer = tail;
				memcpy(tail, element->buffer.pointer,
				       element->buffer.length);
				head += sizeof(u8 *);
				tail += element->buffer.length;
				break;
			default:
				/* Should never get here */
				break;
			}
			break;
		case ACPI_TYPE_LOCAL_REFERENCE:
			switch (format_string[i]) {
			case 'R':
				*(void **)head =
				    (void *)element->reference.handle;
				head += sizeof(void *);
				break;
			default:
				/* Should never get here */
				break;
			}
			break;
		case ACPI_TYPE_PACKAGE:
			/* TBD: handle nested packages... */
		default:
			/* Should never get here */
			break;
		}
	}

	return AE_OK;
}

EXPORT_SYMBOL(acpi_extract_package);

acpi_status
acpi_evaluate_integer(acpi_handle handle,
		      acpi_string pathname,
		      struct acpi_object_list *arguments, unsigned long long *data)
{
	acpi_status status = AE_OK;
	union acpi_object element;
	struct acpi_buffer buffer = { 0, NULL };

	if (!data)
		return AE_BAD_PARAMETER;

	buffer.length = sizeof(union acpi_object);
	buffer.pointer = &element;
	status = acpi_evaluate_object(handle, pathname, arguments, &buffer);
	if (ACPI_FAILURE(status)) {
		acpi_util_eval_error(handle, pathname, status);
		return status;
	}

	if (element.type != ACPI_TYPE_INTEGER) {
		acpi_util_eval_error(handle, pathname, AE_BAD_DATA);
		return AE_BAD_DATA;
	}

	*data = element.integer.value;

	acpi_handle_debug(handle, "Return value [%llu]\n", *data);

	return AE_OK;
}

EXPORT_SYMBOL(acpi_evaluate_integer);

int acpi_get_local_address(acpi_handle handle, u32 *addr)
{
	unsigned long long adr;
	acpi_status status;

	status = acpi_evaluate_integer(handle, METHOD_NAME__ADR, NULL, &adr);
	if (ACPI_FAILURE(status))
		return -ENODATA;

	*addr = (u32)adr;
	return 0;
}
EXPORT_SYMBOL(acpi_get_local_address);

acpi_status
acpi_evaluate_reference(acpi_handle handle,
			acpi_string pathname,
			struct acpi_object_list *arguments,
			struct acpi_handle_list *list)
{
	acpi_status status = AE_OK;
	union acpi_object *package = NULL;
	union acpi_object *element = NULL;
	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
	u32 i = 0;


	if (!list) {
		return AE_BAD_PARAMETER;
	}

	/* Evaluate object. */

	status = acpi_evaluate_object(handle, pathname, arguments, &buffer);
	if (ACPI_FAILURE(status))
		goto end;

	package = buffer.pointer;

	if ((buffer.length == 0) || !package) {
		status = AE_BAD_DATA;
		acpi_util_eval_error(handle, pathname, status);
		goto end;
	}
	if (package->type != ACPI_TYPE_PACKAGE) {
		status = AE_BAD_DATA;
		acpi_util_eval_error(handle, pathname, status);
		goto end;
	}
	if (!package->package.count) {
		status = AE_BAD_DATA;
		acpi_util_eval_error(handle, pathname, status);
		goto end;
	}

	if (package->package.count > ACPI_MAX_HANDLES) {
		kfree(package);
		return AE_NO_MEMORY;
	}
	list->count = package->package.count;

	/* Extract package data. */

	for (i = 0; i < list->count; i++) {

		element = &(package->package.elements[i]);

		if (element->type != ACPI_TYPE_LOCAL_REFERENCE) {
			status = AE_BAD_DATA;
			acpi_util_eval_error(handle, pathname, status);
			break;
		}

		if (!element->reference.handle) {
			status = AE_NULL_ENTRY;
			acpi_util_eval_error(handle, pathname, status);
			break;
		}
		/* Get the  acpi_handle. */

		list->handles[i] = element->reference.handle;
		acpi_handle_debug(list->handles[i], "Found in reference list\n");
	}

      end:
	if (ACPI_FAILURE(status)) {
		list->count = 0;
		//kfree(list->handles);
	}

	kfree(buffer.pointer);

	return status;
}

EXPORT_SYMBOL(acpi_evaluate_reference);

acpi_status
acpi_get_physical_device_location(acpi_handle handle, struct acpi_pld_info **pld)
{
	acpi_status status;
	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
	union acpi_object *output;

	status = acpi_evaluate_object(handle, "_PLD", NULL, &buffer);

	if (ACPI_FAILURE(status))
		return status;

	output = buffer.pointer;

	if (!output || output->type != ACPI_TYPE_PACKAGE
	    || !output->package.count
	    || output->package.elements[0].type != ACPI_TYPE_BUFFER
	    || output->package.elements[0].buffer.length < ACPI_PLD_REV1_BUFFER_SIZE) {
		status = AE_TYPE;
		goto out;
	}

	status = acpi_decode_pld_buffer(
			output->package.elements[0].buffer.pointer,
			output->package.elements[0].buffer.length,
			pld);

out:
	kfree(buffer.pointer);
	return status;
}
EXPORT_SYMBOL(acpi_get_physical_device_location);

/**
 * acpi_evaluate_ost: Evaluate _OST for hotplug operations
 * @handle: ACPI device handle
 * @source_event: source event code
 * @status_code: status code
 * @status_buf: optional detailed information (NULL if none)
 *
 * Evaluate _OST for hotplug operations. All ACPI hotplug handlers
 * must call this function when evaluating _OST for hotplug operations.
 * When the platform does not support _OST, this function has no effect.
 */
acpi_status
acpi_evaluate_ost(acpi_handle handle, u32 source_event, u32 status_code,
		  struct acpi_buffer *status_buf)
{
	union acpi_object params[3] = {
		{.type = ACPI_TYPE_INTEGER,},
		{.type = ACPI_TYPE_INTEGER,},
		{.type = ACPI_TYPE_BUFFER,}
	};
	struct acpi_object_list arg_list = {3, params};

	params[0].integer.value = source_event;
	params[1].integer.value = status_code;
	if (status_buf != NULL) {
		params[2].buffer.pointer = status_buf->pointer;
		params[2].buffer.length = status_buf->length;
	} else {
		params[2].buffer.pointer = NULL;
		params[2].buffer.length = 0;
	}

	return acpi_evaluate_object(handle, "_OST", &arg_list, NULL);
}
EXPORT_SYMBOL(acpi_evaluate_ost);

/**
 * acpi_handle_path: Return the object path of handle
 * @handle: ACPI device handle
 *
 * Caller must free the returned buffer
 */
static char *acpi_handle_path(acpi_handle handle)
{
	struct acpi_buffer buffer = {
		.length = ACPI_ALLOCATE_BUFFER,
		.pointer = NULL
	};

	if (in_interrupt() ||
	    acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer) != AE_OK)
		return NULL;
	return buffer.pointer;
}

/**
 * acpi_handle_printk: Print message with ACPI prefix and object path
 * @level: log level
 * @handle: ACPI device handle
 * @fmt: format string
 *
 * This function is called through acpi_handle_<level> macros and prints
 * a message with ACPI prefix and object path.  This function acquires
 * the global namespace mutex to obtain an object path.  In interrupt
 * context, it shows the object path as <n/a>.
 */
void
acpi_handle_printk(const char *level, acpi_handle handle, const char *fmt, ...)
{
	struct va_format vaf;
	va_list args;
	const char *path;

	va_start(args, fmt);
	vaf.fmt = fmt;
	vaf.va = &args;

	path = acpi_handle_path(handle);
	printk("%sACPI: %s: %pV", level, path ? path : "<n/a>" , &vaf);

	va_end(args);
	kfree(path);
}
EXPORT_SYMBOL(acpi_handle_printk);

#if defined(CONFIG_DYNAMIC_DEBUG)
/**
 * __acpi_handle_debug: pr_debug with ACPI prefix and object path
 * @descriptor: Dynamic Debug descriptor
 * @handle: ACPI device handle
 * @fmt: format string
 *
 * This function is called through acpi_handle_debug macro and debug
 * prints a message with ACPI prefix and object path. This function
 * acquires the global namespace mutex to obtain an object path.  In
 * interrupt context, it shows the object path as <n/a>.
 */
void
__acpi_handle_debug(struct _ddebug *descriptor, acpi_handle handle,
		    const char *fmt, ...)
{
	struct va_format vaf;
	va_list args;
	const char *path;

	va_start(args, fmt);
	vaf.fmt = fmt;
	vaf.va = &args;

	path = acpi_handle_path(handle);
	__dynamic_pr_debug(descriptor, "ACPI: %s: %pV", path ? path : "<n/a>", &vaf);

	va_end(args);
	kfree(path);
}
EXPORT_SYMBOL(__acpi_handle_debug);
#endif

/**
 * acpi_evaluation_failure_warn - Log evaluation failure warning.
 * @handle: Parent object handle.
 * @name: Name of the object whose evaluation has failed.
 * @status: Status value returned by the failing object evaluation.
 */
void acpi_evaluation_failure_warn(acpi_handle handle, const char *name,
				  acpi_status status)
{
	acpi_handle_warn(handle, "%s evaluation failed: %s\n", name,
			 acpi_format_exception(status));
}
EXPORT_SYMBOL_GPL(acpi_evaluation_failure_warn);

/**
 * acpi_has_method: Check whether @handle has a method named @name
 * @handle: ACPI device handle
 * @name: name of object or method
 *
 * Check whether @handle has a method named @name.
 */
bool acpi_has_method(acpi_handle handle, char *name)
{
	acpi_handle tmp;

	return ACPI_SUCCESS(acpi_get_handle(handle, name, &tmp));
}
EXPORT_SYMBOL(acpi_has_method);

acpi_status acpi_execute_simple_method(acpi_handle handle, char *method,
				       u64 arg)
{
	union acpi_object obj = { .type = ACPI_TYPE_INTEGER };
	struct acpi_object_list arg_list = { .count = 1, .pointer = &obj, };

	obj.integer.value = arg;

	return acpi_evaluate_object(handle, method, &arg_list, NULL);
}
EXPORT_SYMBOL(acpi_execute_simple_method);

/**
 * acpi_evaluate_ej0: Evaluate _EJ0 method for hotplug operations
 * @handle: ACPI device handle
 *
 * Evaluate device's _EJ0 method for hotplug operations.
 */
acpi_status acpi_evaluate_ej0(acpi_handle handle)
{
	acpi_status status;

	status = acpi_execute_simple_method(handle, "_EJ0", 1);
	if (status == AE_NOT_FOUND)
		acpi_handle_warn(handle, "No _EJ0 support for device\n");
	else if (ACPI_FAILURE(status))
		acpi_handle_warn(handle, "Eject failed (0x%x)\n", status);

	return status;
}

/**
 * acpi_evaluate_lck: Evaluate _LCK method to lock/unlock device
 * @handle: ACPI device handle
 * @lock: lock device if non-zero, otherwise unlock device
 *
 * Evaluate device's _LCK method if present to lock/unlock device
 */
acpi_status acpi_evaluate_lck(acpi_handle handle, int lock)
{
	acpi_status status;

	status = acpi_execute_simple_method(handle, "_LCK", !!lock);
	if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {
		if (lock)
			acpi_handle_warn(handle,
				"Locking device failed (0x%x)\n", status);
		else
			acpi_handle_warn(handle,
				"Unlocking device failed (0x%x)\n", status);
	}

	return status;
}

/**
 * acpi_evaluate_reg: Evaluate _REG method to register OpRegion presence
 * @handle: ACPI device handle
 * @space_id: ACPI address space id to register OpRegion presence for
 * @function: Parameter to pass to _REG one of ACPI_REG_CONNECT or
 *            ACPI_REG_DISCONNECT
 *
 * Evaluate device's _REG method to register OpRegion presence.
 */
acpi_status acpi_evaluate_reg(acpi_handle handle, u8 space_id, u32 function)
{
	struct acpi_object_list arg_list;
	union acpi_object params[2];

	params[0].type = ACPI_TYPE_INTEGER;
	params[0].integer.value = space_id;
	params[1].type = ACPI_TYPE_INTEGER;
	params[1].integer.value = function;
	arg_list.count = 2;
	arg_list.pointer = params;

	return acpi_evaluate_object(handle, "_REG", &arg_list, NULL);
}
EXPORT_SYMBOL(acpi_evaluate_reg);

/**
 * acpi_evaluate_dsm - evaluate device's _DSM method
 * @handle: ACPI device handle
 * @guid: GUID of requested functions, should be 16 bytes
 * @rev: revision number of requested function
 * @func: requested function number
 * @argv4: the function specific parameter
 *
 * Evaluate device's _DSM method with specified GUID, revision id and
 * function number. Caller needs to free the returned object.
 *
 * Though ACPI defines the fourth parameter for _DSM should be a package,
 * some old BIOSes do expect a buffer or an integer etc.
 */
union acpi_object *
acpi_evaluate_dsm(acpi_handle handle, const guid_t *guid, u64 rev, u64 func,
		  union acpi_object *argv4)
{
	acpi_status ret;
	struct acpi_buffer buf = {ACPI_ALLOCATE_BUFFER, NULL};
	union acpi_object params[4];
	struct acpi_object_list input = {
		.count = 4,
		.pointer = params,
	};

	params[0].type = ACPI_TYPE_BUFFER;
	params[0].buffer.length = 16;
	params[0].buffer.pointer = (u8 *)guid;
	params[1].type = ACPI_TYPE_INTEGER;
	params[1].integer.value = rev;
	params[2].type = ACPI_TYPE_INTEGER;
	params[2].integer.value = func;
	if (argv4) {
		params[3] = *argv4;
	} else {
		params[3].type = ACPI_TYPE_PACKAGE;
		params[3].package.count = 0;
		params[3].package.elements = NULL;
	}

	ret = acpi_evaluate_object(handle, "_DSM", &input, &buf);
	if (ACPI_SUCCESS(ret))
		return (union acpi_object *)buf.pointer;

	if (ret != AE_NOT_FOUND)
		acpi_handle_warn(handle,
				"failed to evaluate _DSM (0x%x)\n", ret);

	return NULL;
}
EXPORT_SYMBOL(acpi_evaluate_dsm);

/**
 * acpi_check_dsm - check if _DSM method supports requested functions.
 * @handle: ACPI device handle
 * @guid: GUID of requested functions, should be 16 bytes at least
 * @rev: revision number of requested functions
 * @funcs: bitmap of requested functions
 *
 * Evaluate device's _DSM method to check whether it supports requested
 * functions. Currently only support 64 functions at maximum, should be
 * enough for now.
 */
bool acpi_check_dsm(acpi_handle handle, const guid_t *guid, u64 rev, u64 funcs)
{
	int i;
	u64 mask = 0;
	union acpi_object *obj;

	if (funcs == 0)
		return false;

	obj = acpi_evaluate_dsm(handle, guid, rev, 0, NULL);
	if (!obj)
		return false;

	/* For compatibility, old BIOSes may return an integer */
	if (obj->type == ACPI_TYPE_INTEGER)
		mask = obj->integer.value;
	else if (obj->type == ACPI_TYPE_BUFFER)
		for (i = 0; i < obj->buffer.length && i < 8; i++)
			mask |= (((u64)obj->buffer.pointer[i]) << (i * 8));
	ACPI_FREE(obj);

	/*
	 * Bit 0 indicates whether there's support for any functions other than
	 * function 0 for the specified GUID and revision.
	 */
	if ((mask & 0x1) && (mask & funcs) == funcs)
		return true;

	return false;
}
EXPORT_SYMBOL(acpi_check_dsm);

/**
 * acpi_dev_hid_uid_match - Match device by supplied HID and UID
 * @adev: ACPI device to match.
 * @hid2: Hardware ID of the device.
 * @uid2: Unique ID of the device, pass NULL to not check _UID.
 *
 * Matches HID and UID in @adev with given @hid2 and @uid2.
 * Returns true if matches.
 */
bool acpi_dev_hid_uid_match(struct acpi_device *adev,
			    const char *hid2, const char *uid2)
{
	const char *hid1 = acpi_device_hid(adev);
	const char *uid1 = acpi_device_uid(adev);

	if (strcmp(hid1, hid2))
		return false;

	if (!uid2)
		return true;

	return uid1 && !strcmp(uid1, uid2);
}
EXPORT_SYMBOL(acpi_dev_hid_uid_match);

/**
 * acpi_dev_found - Detect presence of a given ACPI device in the namespace.
 * @hid: Hardware ID of the device.
 *
 * Return %true if the device was present at the moment of invocation.
 * Note that if the device is pluggable, it may since have disappeared.
 *
 * For this function to work, acpi_bus_scan() must have been executed
 * which happens in the subsys_initcall() subsection. Hence, do not
 * call from a subsys_initcall() or earlier (use acpi_get_devices()
 * instead). Calling from module_init() is fine (which is synonymous
 * with device_initcall()).
 */
bool acpi_dev_found(const char *hid)
{
	struct acpi_device_bus_id *acpi_device_bus_id;
	bool found = false;

	mutex_lock(&acpi_device_lock);
	list_for_each_entry(acpi_device_bus_id, &acpi_bus_id_list, node)
		if (!strcmp(acpi_device_bus_id->bus_id, hid)) {
			found = true;
			break;
		}
	mutex_unlock(&acpi_device_lock);

	return found;
}
EXPORT_SYMBOL(acpi_dev_found);

struct acpi_dev_match_info {
	struct acpi_device_id hid[2];
	const char *uid;
	s64 hrv;
};

static int acpi_dev_match_cb(struct device *dev, const void *data)
{
	struct acpi_device *adev = to_acpi_device(dev);
	const struct acpi_dev_match_info *match = data;
	unsigned long long hrv;
	acpi_status status;

	if (acpi_match_device_ids(adev, match->hid))
		return 0;

	if (match->uid && (!adev->pnp.unique_id ||
	    strcmp(adev->pnp.unique_id, match->uid)))
		return 0;

	if (match->hrv == -1)
		return 1;

	status = acpi_evaluate_integer(adev->handle, "_HRV", NULL, &hrv);
	if (ACPI_FAILURE(status))
		return 0;

	return hrv == match->hrv;
}

/**
 * acpi_dev_present - Detect that a given ACPI device is present
 * @hid: Hardware ID of the device.
 * @uid: Unique ID of the device, pass NULL to not check _UID
 * @hrv: Hardware Revision of the device, pass -1 to not check _HRV
 *
 * Return %true if a matching device was present at the moment of invocation.
 * Note that if the device is pluggable, it may since have disappeared.
 *
 * Note that unlike acpi_dev_found() this function checks the status
 * of the device. So for devices which are present in the DSDT, but
 * which are disabled (their _STA callback returns 0) this function
 * will return false.
 *
 * For this function to work, acpi_bus_scan() must have been executed
 * which happens in the subsys_initcall() subsection. Hence, do not
 * call from a subsys_initcall() or earlier (use acpi_get_devices()
 * instead). Calling from module_init() is fine (which is synonymous
 * with device_initcall()).
 */
bool acpi_dev_present(const char *hid, const char *uid, s64 hrv)
{
	struct acpi_dev_match_info match = {};
	struct device *dev;

	strlcpy(match.hid[0].id, hid, sizeof(match.hid[0].id));
	match.uid = uid;
	match.hrv = hrv;

	dev = bus_find_device(&acpi_bus_type, NULL, &match, acpi_dev_match_cb);
	put_device(dev);
	return !!dev;
}
EXPORT_SYMBOL(acpi_dev_present);

/**
 * acpi_dev_get_next_match_dev - Return the next match of ACPI device
 * @adev: Pointer to the previous ACPI device matching this @hid, @uid and @hrv
 * @hid: Hardware ID of the device.
 * @uid: Unique ID of the device, pass NULL to not check _UID
 * @hrv: Hardware Revision of the device, pass -1 to not check _HRV
 *
 * Return the next match of ACPI device if another matching device was present
 * at the moment of invocation, or NULL otherwise.
 *
 * FIXME: The function does not tolerate the sudden disappearance of @adev, e.g.
 * in the case of a hotplug event. That said, the caller should ensure that
 * this will never happen.
 *
 * The caller is responsible for invoking acpi_dev_put() on the returned device.
 *
 * See additional information in acpi_dev_present() as well.
 */
struct acpi_device *
acpi_dev_get_next_match_dev(struct acpi_device *adev, const char *hid, const char *uid, s64 hrv)
{
	struct device *start = adev ? &adev->dev : NULL;
	struct acpi_dev_match_info match = {};
	struct device *dev;

	strlcpy(match.hid[0].id, hid, sizeof(match.hid[0].id));
	match.uid = uid;
	match.hrv = hrv;

	dev = bus_find_device(&acpi_bus_type, start, &match, acpi_dev_match_cb);
	return dev ? to_acpi_device(dev) : NULL;
}
EXPORT_SYMBOL(acpi_dev_get_next_match_dev);

/**
 * acpi_dev_get_first_match_dev - Return the first match of ACPI device
 * @hid: Hardware ID of the device.
 * @uid: Unique ID of the device, pass NULL to not check _UID
 * @hrv: Hardware Revision of the device, pass -1 to not check _HRV
 *
 * Return the first match of ACPI device if a matching device was present
 * at the moment of invocation, or NULL otherwise.
 *
 * The caller is responsible for invoking acpi_dev_put() on the returned device.
 *
 * See additional information in acpi_dev_present() as well.
 */
struct acpi_device *
acpi_dev_get_first_match_dev(const char *hid, const char *uid, s64 hrv)
{
	return acpi_dev_get_next_match_dev(NULL, hid, uid, hrv);
}
EXPORT_SYMBOL(acpi_dev_get_first_match_dev);

/**
 * acpi_reduced_hardware - Return if this is an ACPI-reduced-hw machine
 *
 * Return true when running on an ACPI-reduced-hw machine, false otherwise.
 */
bool acpi_reduced_hardware(void)
{
	return acpi_gbl_reduced_hardware;
}
EXPORT_SYMBOL_GPL(acpi_reduced_hardware);

/*
 * acpi_backlight= handling, this is done here rather then in video_detect.c
 * because __setup cannot be used in modules.
 */
char acpi_video_backlight_string[16];
EXPORT_SYMBOL(acpi_video_backlight_string);

static int __init acpi_backlight(char *str)
{
	strlcpy(acpi_video_backlight_string, str,
		sizeof(acpi_video_backlight_string));
	return 1;
}
__setup("acpi_backlight=", acpi_backlight);

/**
 * acpi_match_platform_list - Check if the system matches with a given list
 * @plat: pointer to acpi_platform_list table terminated by a NULL entry
 *
 * Return the matched index if the system is found in the platform list.
 * Otherwise, return a negative error code.
 */
int acpi_match_platform_list(const struct acpi_platform_list *plat)
{
	struct acpi_table_header hdr;
	int idx = 0;

	if (acpi_disabled)
		return -ENODEV;

	for (; plat->oem_id[0]; plat++, idx++) {
		if (ACPI_FAILURE(acpi_get_table_header(plat->table, 0, &hdr)))
			continue;

		if (strncmp(plat->oem_id, hdr.oem_id, ACPI_OEM_ID_SIZE))
			continue;

		if (strncmp(plat->oem_table_id, hdr.oem_table_id, ACPI_OEM_TABLE_ID_SIZE))
			continue;

		if ((plat->pred == all_versions) ||
		    (plat->pred == less_than_or_equal && hdr.oem_revision <= plat->oem_revision) ||
		    (plat->pred == greater_than_or_equal && hdr.oem_revision >= plat->oem_revision) ||
		    (plat->pred == equal && hdr.oem_revision == plat->oem_revision))
			return idx;
	}

	return -ENODEV;
}
EXPORT_SYMBOL(acpi_match_platform_list);