1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 *  acpi_utils.c - ACPI Utility Functions ($Revision: 10 $)
   4 *
   5 *  Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
   6 *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
   7 */
   8
   9#define pr_fmt(fmt) "ACPI: utils: " fmt
  10
  11#include <linux/kernel.h>
  12#include <linux/module.h>
  13#include <linux/slab.h>
  14#include <linux/init.h>
  15#include <linux/types.h>
  16#include <linux/hardirq.h>
  17#include <linux/acpi.h>
  18#include <linux/dynamic_debug.h>
  19
  20#include "internal.h"
  21#include "sleep.h"
  22
  23/* --------------------------------------------------------------------------
  24                            Object Evaluation Helpers
  25   -------------------------------------------------------------------------- */
  26static void acpi_util_eval_error(acpi_handle h, acpi_string p, acpi_status s)
  27{
  28	acpi_handle_debug(h, "Evaluate [%s]: %s\n", p, acpi_format_exception(s));
  29}
  30
  31acpi_status
  32acpi_extract_package(union acpi_object *package,
  33		     struct acpi_buffer *format, struct acpi_buffer *buffer)
  34{
  35	u32 size_required = 0;
  36	u32 tail_offset = 0;
  37	char *format_string = NULL;
  38	u32 format_count = 0;
  39	u32 i = 0;
  40	u8 *head = NULL;
  41	u8 *tail = NULL;
  42
  43
  44	if (!package || (package->type != ACPI_TYPE_PACKAGE)
  45	    || (package->package.count < 1)) {
  46		pr_debug("Invalid package argument\n");
  47		return AE_BAD_PARAMETER;
  48	}
  49
  50	if (!format || !format->pointer || (format->length < 1)) {
  51		pr_debug("Invalid format argument\n");
  52		return AE_BAD_PARAMETER;
  53	}
  54
  55	if (!buffer) {
  56		pr_debug("Invalid buffer argument\n");
  57		return AE_BAD_PARAMETER;
  58	}
  59
  60	format_count = (format->length / sizeof(char)) - 1;
  61	if (format_count > package->package.count) {
  62		pr_debug("Format specifies more objects [%d] than present [%d]\n",
  63			 format_count, package->package.count);
  64		return AE_BAD_DATA;
  65	}
  66
  67	format_string = format->pointer;
  68
  69	/*
  70	 * Calculate size_required.
  71	 */
  72	for (i = 0; i < format_count; i++) {
  73
  74		union acpi_object *element = &(package->package.elements[i]);
  75
  76		switch (element->type) {
  77
  78		case ACPI_TYPE_INTEGER:
  79			switch (format_string[i]) {
  80			case 'N':
  81				size_required += sizeof(u64);
  82				tail_offset += sizeof(u64);
  83				break;
  84			case 'S':
  85				size_required +=
  86				    sizeof(char *) + sizeof(u64) +
  87				    sizeof(char);
  88				tail_offset += sizeof(char *);
  89				break;
  90			default:
  91				pr_debug("Invalid package element [%d]: got number, expected [%c]\n",
  92					 i, format_string[i]);
  93				return AE_BAD_DATA;
  94			}
  95			break;
  96
  97		case ACPI_TYPE_STRING:
  98		case ACPI_TYPE_BUFFER:
  99			switch (format_string[i]) {
 100			case 'S':
 101				size_required +=
 102				    sizeof(char *) +
 103				    (element->string.length * sizeof(char)) +
 104				    sizeof(char);
 105				tail_offset += sizeof(char *);
 106				break;
 107			case 'B':
 108				size_required +=
 109				    sizeof(u8 *) + element->buffer.length;
 110				tail_offset += sizeof(u8 *);
 111				break;
 112			default:
 113				pr_debug("Invalid package element [%d] got string/buffer, expected [%c]\n",
 114					 i, format_string[i]);
 115				return AE_BAD_DATA;
 116			}
 117			break;
 118		case ACPI_TYPE_LOCAL_REFERENCE:
 119			switch (format_string[i]) {
 120			case 'R':
 121				size_required += sizeof(void *);
 122				tail_offset += sizeof(void *);
 123				break;
 124			default:
 125				pr_debug("Invalid package element [%d] got reference, expected [%c]\n",
 126					 i, format_string[i]);
 127				return AE_BAD_DATA;
 128			}
 129			break;
 130
 131		case ACPI_TYPE_PACKAGE:
 132		default:
 133			pr_debug("Unsupported element at index=%d\n", i);
 134			/* TBD: handle nested packages... */
 135			return AE_SUPPORT;
 136		}
 137	}
 138
 139	/*
 140	 * Validate output buffer.
 141	 */
 142	if (buffer->length == ACPI_ALLOCATE_BUFFER) {
 143		buffer->pointer = ACPI_ALLOCATE_ZEROED(size_required);
 144		if (!buffer->pointer)
 145			return AE_NO_MEMORY;
 146		buffer->length = size_required;
 147	} else {
 148		if (buffer->length < size_required) {
 149			buffer->length = size_required;
 150			return AE_BUFFER_OVERFLOW;
 151		} else if (buffer->length != size_required ||
 152			   !buffer->pointer) {
 153			return AE_BAD_PARAMETER;
 154		}
 155	}
 156
 157	head = buffer->pointer;
 158	tail = buffer->pointer + tail_offset;
 159
 160	/*
 161	 * Extract package data.
 162	 */
 163	for (i = 0; i < format_count; i++) {
 164
 165		u8 **pointer = NULL;
 166		union acpi_object *element = &(package->package.elements[i]);
 167
 168		switch (element->type) {
 169
 170		case ACPI_TYPE_INTEGER:
 171			switch (format_string[i]) {
 172			case 'N':
 173				*((u64 *) head) =
 174				    element->integer.value;
 175				head += sizeof(u64);
 176				break;
 177			case 'S':
 178				pointer = (u8 **) head;
 179				*pointer = tail;
 180				*((u64 *) tail) =
 181				    element->integer.value;
 182				head += sizeof(u64 *);
 183				tail += sizeof(u64);
 184				/* NULL terminate string */
 185				*tail = (char)0;
 186				tail += sizeof(char);
 187				break;
 188			default:
 189				/* Should never get here */
 190				break;
 191			}
 192			break;
 193
 194		case ACPI_TYPE_STRING:
 195		case ACPI_TYPE_BUFFER:
 196			switch (format_string[i]) {
 197			case 'S':
 198				pointer = (u8 **) head;
 199				*pointer = tail;
 200				memcpy(tail, element->string.pointer,
 201				       element->string.length);
 202				head += sizeof(char *);
 203				tail += element->string.length * sizeof(char);
 204				/* NULL terminate string */
 205				*tail = (char)0;
 206				tail += sizeof(char);
 207				break;
 208			case 'B':
 209				pointer = (u8 **) head;
 210				*pointer = tail;
 211				memcpy(tail, element->buffer.pointer,
 212				       element->buffer.length);
 213				head += sizeof(u8 *);
 214				tail += element->buffer.length;
 215				break;
 216			default:
 217				/* Should never get here */
 218				break;
 219			}
 220			break;
 221		case ACPI_TYPE_LOCAL_REFERENCE:
 222			switch (format_string[i]) {
 223			case 'R':
 224				*(void **)head =
 225				    (void *)element->reference.handle;
 226				head += sizeof(void *);
 227				break;
 228			default:
 229				/* Should never get here */
 230				break;
 231			}
 232			break;
 233		case ACPI_TYPE_PACKAGE:
 234			/* TBD: handle nested packages... */
 235		default:
 236			/* Should never get here */
 237			break;
 238		}
 239	}
 240
 241	return AE_OK;
 242}
 243
 244EXPORT_SYMBOL(acpi_extract_package);
 245
 246acpi_status
 247acpi_evaluate_integer(acpi_handle handle,
 248		      acpi_string pathname,
 249		      struct acpi_object_list *arguments, unsigned long long *data)
 250{
 251	acpi_status status = AE_OK;
 252	union acpi_object element;
 253	struct acpi_buffer buffer = { 0, NULL };
 254
 255	if (!data)
 256		return AE_BAD_PARAMETER;
 257
 258	buffer.length = sizeof(union acpi_object);
 259	buffer.pointer = &element;
 260	status = acpi_evaluate_object(handle, pathname, arguments, &buffer);
 261	if (ACPI_FAILURE(status)) {
 262		acpi_util_eval_error(handle, pathname, status);
 263		return status;
 264	}
 265
 266	if (element.type != ACPI_TYPE_INTEGER) {
 267		acpi_util_eval_error(handle, pathname, AE_BAD_DATA);
 268		return AE_BAD_DATA;
 269	}
 270
 271	*data = element.integer.value;
 272
 273	acpi_handle_debug(handle, "Return value [%llu]\n", *data);
 274
 275	return AE_OK;
 276}
 277
 278EXPORT_SYMBOL(acpi_evaluate_integer);
 279
 280int acpi_get_local_u64_address(acpi_handle handle, u64 *addr)
 281{
 
 282	acpi_status status;
 283
 284	status = acpi_evaluate_integer(handle, METHOD_NAME__ADR, NULL, addr);
 285	if (ACPI_FAILURE(status))
 286		return -ENODATA;
 287	return 0;
 288}
 289EXPORT_SYMBOL(acpi_get_local_u64_address);
 290
 291int acpi_get_local_address(acpi_handle handle, u32 *addr)
 292{
 293	u64 adr;
 294	int ret;
 295
 296	ret = acpi_get_local_u64_address(handle, &adr);
 297	if (ret < 0)
 298		return ret;
 299	*addr = (u32)adr;
 300	return 0;
 301}
 302EXPORT_SYMBOL(acpi_get_local_address);
 303
 304#define ACPI_MAX_SUB_BUF_SIZE	9
 305
 306const char *acpi_get_subsystem_id(acpi_handle handle)
 307{
 
 
 
 
 
 308	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
 309	union acpi_object *obj;
 310	acpi_status status;
 311	const char *sub;
 312	size_t len;
 313
 314	status = acpi_evaluate_object(handle, METHOD_NAME__SUB, NULL, &buffer);
 315	if (ACPI_FAILURE(status)) {
 316		acpi_handle_debug(handle, "Reading ACPI _SUB failed: %#x\n", status);
 317		return ERR_PTR(-ENODATA);
 318	}
 319
 320	obj = buffer.pointer;
 321	if (obj->type == ACPI_TYPE_STRING) {
 322		len = strlen(obj->string.pointer);
 323		if (len < ACPI_MAX_SUB_BUF_SIZE && len > 0) {
 324			sub = kstrdup(obj->string.pointer, GFP_KERNEL);
 325			if (!sub)
 326				sub = ERR_PTR(-ENOMEM);
 327		} else {
 328			acpi_handle_err(handle, "ACPI _SUB Length %zu is Invalid\n", len);
 329			sub = ERR_PTR(-ENODATA);
 330		}
 331	} else {
 332		acpi_handle_warn(handle, "Warning ACPI _SUB did not return a string\n");
 333		sub = ERR_PTR(-ENODATA);
 334	}
 335
 336	acpi_os_free(buffer.pointer);
 337
 338	return sub;
 339}
 340EXPORT_SYMBOL_GPL(acpi_get_subsystem_id);
 341
 342bool acpi_evaluate_reference(acpi_handle handle, acpi_string pathname,
 343			     struct acpi_object_list *arguments,
 344			     struct acpi_handle_list *list)
 345{
 346	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
 347	union acpi_object *package;
 348	acpi_status status;
 349	bool ret = false;
 350	u32 i;
 351
 352	if (!list)
 353		return false;
 354
 355	/* Evaluate object. */
 356
 357	status = acpi_evaluate_object(handle, pathname, arguments, &buffer);
 358	if (ACPI_FAILURE(status))
 359		goto end;
 360
 361	package = buffer.pointer;
 362
 363	if (buffer.length == 0 || !package ||
 364	    package->type != ACPI_TYPE_PACKAGE || !package->package.count)
 365		goto err;
 
 
 
 
 
 
 
 
 
 
 
 
 366
 
 
 
 
 367	list->count = package->package.count;
 368	list->handles = kcalloc(list->count, sizeof(*list->handles), GFP_KERNEL);
 369	if (!list->handles)
 370		goto err_clear;
 371
 372	/* Extract package data. */
 373
 374	for (i = 0; i < list->count; i++) {
 375		union acpi_object *element = &(package->package.elements[i]);
 376
 377		if (element->type != ACPI_TYPE_LOCAL_REFERENCE ||
 378		    !element->reference.handle)
 379			goto err_free;
 380
 
 
 
 
 
 
 
 
 
 
 
 381		/* Get the  acpi_handle. */
 382
 383		list->handles[i] = element->reference.handle;
 384		acpi_handle_debug(list->handles[i], "Found in reference list\n");
 385	}
 386
 387	ret = true;
 
 
 
 
 388
 389end:
 390	kfree(buffer.pointer);
 391
 392	return ret;
 393
 394err_free:
 395	kfree(list->handles);
 396	list->handles = NULL;
 397
 398err_clear:
 399	list->count = 0;
 400
 401err:
 402	acpi_util_eval_error(handle, pathname, status);
 403	goto end;
 404}
 405
 406EXPORT_SYMBOL(acpi_evaluate_reference);
 407
 408/**
 409 * acpi_handle_list_equal - Check if two ACPI handle lists are the same
 410 * @list1: First list to compare.
 411 * @list2: Second list to compare.
 412 *
 413 * Return true if the given ACPI handle lists are of the same size and
 414 * contain the same ACPI handles in the same order.  Otherwise, return false.
 415 */
 416bool acpi_handle_list_equal(struct acpi_handle_list *list1,
 417			    struct acpi_handle_list *list2)
 418{
 419	return list1->count == list2->count &&
 420		!memcmp(list1->handles, list2->handles,
 421		        list1->count * sizeof(*list1->handles));
 422}
 423EXPORT_SYMBOL_GPL(acpi_handle_list_equal);
 424
 425/**
 426 * acpi_handle_list_replace - Replace one ACPI handle list with another
 427 * @dst: ACPI handle list to replace.
 428 * @src: Source ACPI handle list.
 429 *
 430 * Free the handles table in @dst, move the handles table from @src to @dst,
 431 * copy count from @src to @dst and clear @src.
 432 */
 433void acpi_handle_list_replace(struct acpi_handle_list *dst,
 434			      struct acpi_handle_list *src)
 435{
 436	if (dst->count)
 437		kfree(dst->handles);
 438
 439	dst->count = src->count;
 440	dst->handles = src->handles;
 441
 442	src->handles = NULL;
 443	src->count = 0;
 444}
 445EXPORT_SYMBOL_GPL(acpi_handle_list_replace);
 446
 447/**
 448 * acpi_handle_list_free - Free the handles table in an ACPI handle list
 449 * @list: ACPI handle list to free.
 450 *
 451 * Free the handles table in @list and clear its count field.
 452 */
 453void acpi_handle_list_free(struct acpi_handle_list *list)
 454{
 455	if (!list->count)
 456		return;
 457
 458	kfree(list->handles);
 459	list->count = 0;
 460}
 461EXPORT_SYMBOL_GPL(acpi_handle_list_free);
 462
 463/**
 464 * acpi_device_dep - Check ACPI device dependency
 465 * @target: ACPI handle of the target ACPI device.
 466 * @match: ACPI handle to look up in the target's _DEP list.
 467 *
 468 * Return true if @match is present in the list returned by _DEP for
 469 * @target or false otherwise.
 470 */
 471bool acpi_device_dep(acpi_handle target, acpi_handle match)
 472{
 473	struct acpi_handle_list dep_devices;
 474	bool ret = false;
 475	int i;
 476
 477	if (!acpi_has_method(target, "_DEP"))
 478		return false;
 479
 480	if (!acpi_evaluate_reference(target, "_DEP", NULL, &dep_devices)) {
 481		acpi_handle_debug(target, "Failed to evaluate _DEP.\n");
 482		return false;
 483	}
 484
 485	for (i = 0; i < dep_devices.count; i++) {
 486		if (dep_devices.handles[i] == match) {
 487			ret = true;
 488			break;
 489		}
 490	}
 491
 492	acpi_handle_list_free(&dep_devices);
 493	return ret;
 494}
 495EXPORT_SYMBOL_GPL(acpi_device_dep);
 496
 497acpi_status
 498acpi_get_physical_device_location(acpi_handle handle, struct acpi_pld_info **pld)
 499{
 500	acpi_status status;
 501	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
 502	union acpi_object *output;
 503
 504	status = acpi_evaluate_object(handle, "_PLD", NULL, &buffer);
 505
 506	if (ACPI_FAILURE(status))
 507		return status;
 508
 509	output = buffer.pointer;
 510
 511	if (!output || output->type != ACPI_TYPE_PACKAGE
 512	    || !output->package.count
 513	    || output->package.elements[0].type != ACPI_TYPE_BUFFER
 514	    || output->package.elements[0].buffer.length < ACPI_PLD_REV1_BUFFER_SIZE) {
 515		status = AE_TYPE;
 516		goto out;
 517	}
 518
 519	status = acpi_decode_pld_buffer(
 520			output->package.elements[0].buffer.pointer,
 521			output->package.elements[0].buffer.length,
 522			pld);
 523
 524out:
 525	kfree(buffer.pointer);
 526	return status;
 527}
 528EXPORT_SYMBOL(acpi_get_physical_device_location);
 529
 530/**
 531 * acpi_evaluate_ost: Evaluate _OST for hotplug operations
 532 * @handle: ACPI device handle
 533 * @source_event: source event code
 534 * @status_code: status code
 535 * @status_buf: optional detailed information (NULL if none)
 536 *
 537 * Evaluate _OST for hotplug operations. All ACPI hotplug handlers
 538 * must call this function when evaluating _OST for hotplug operations.
 539 * When the platform does not support _OST, this function has no effect.
 540 */
 541acpi_status
 542acpi_evaluate_ost(acpi_handle handle, u32 source_event, u32 status_code,
 543		  struct acpi_buffer *status_buf)
 544{
 545	union acpi_object params[3] = {
 546		{.type = ACPI_TYPE_INTEGER,},
 547		{.type = ACPI_TYPE_INTEGER,},
 548		{.type = ACPI_TYPE_BUFFER,}
 549	};
 550	struct acpi_object_list arg_list = {3, params};
 551
 552	params[0].integer.value = source_event;
 553	params[1].integer.value = status_code;
 554	if (status_buf != NULL) {
 555		params[2].buffer.pointer = status_buf->pointer;
 556		params[2].buffer.length = status_buf->length;
 557	} else {
 558		params[2].buffer.pointer = NULL;
 559		params[2].buffer.length = 0;
 560	}
 561
 562	return acpi_evaluate_object(handle, "_OST", &arg_list, NULL);
 563}
 564EXPORT_SYMBOL(acpi_evaluate_ost);
 565
 566/**
 567 * acpi_handle_path: Return the object path of handle
 568 * @handle: ACPI device handle
 569 *
 570 * Caller must free the returned buffer
 571 */
 572char *acpi_handle_path(acpi_handle handle)
 573{
 574	struct acpi_buffer buffer = {
 575		.length = ACPI_ALLOCATE_BUFFER,
 576		.pointer = NULL
 577	};
 578
 579	if (in_interrupt() ||
 580	    acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer) != AE_OK)
 581		return NULL;
 582	return buffer.pointer;
 583}
 584
 585/**
 586 * acpi_handle_printk: Print message with ACPI prefix and object path
 587 * @level: log level
 588 * @handle: ACPI device handle
 589 * @fmt: format string
 590 *
 591 * This function is called through acpi_handle_<level> macros and prints
 592 * a message with ACPI prefix and object path.  This function acquires
 593 * the global namespace mutex to obtain an object path.  In interrupt
 594 * context, it shows the object path as <n/a>.
 595 */
 596void
 597acpi_handle_printk(const char *level, acpi_handle handle, const char *fmt, ...)
 598{
 599	struct va_format vaf;
 600	va_list args;
 601	const char *path;
 602
 603	va_start(args, fmt);
 604	vaf.fmt = fmt;
 605	vaf.va = &args;
 606
 607	path = acpi_handle_path(handle);
 608	printk("%sACPI: %s: %pV", level, path ? path : "<n/a>", &vaf);
 609
 610	va_end(args);
 611	kfree(path);
 612}
 613EXPORT_SYMBOL(acpi_handle_printk);
 614
 615#if defined(CONFIG_DYNAMIC_DEBUG)
 616/**
 617 * __acpi_handle_debug: pr_debug with ACPI prefix and object path
 618 * @descriptor: Dynamic Debug descriptor
 619 * @handle: ACPI device handle
 620 * @fmt: format string
 621 *
 622 * This function is called through acpi_handle_debug macro and debug
 623 * prints a message with ACPI prefix and object path. This function
 624 * acquires the global namespace mutex to obtain an object path.  In
 625 * interrupt context, it shows the object path as <n/a>.
 626 */
 627void
 628__acpi_handle_debug(struct _ddebug *descriptor, acpi_handle handle,
 629		    const char *fmt, ...)
 630{
 631	struct va_format vaf;
 632	va_list args;
 633	const char *path;
 634
 635	va_start(args, fmt);
 636	vaf.fmt = fmt;
 637	vaf.va = &args;
 638
 639	path = acpi_handle_path(handle);
 640	__dynamic_pr_debug(descriptor, "ACPI: %s: %pV", path ? path : "<n/a>", &vaf);
 641
 642	va_end(args);
 643	kfree(path);
 644}
 645EXPORT_SYMBOL(__acpi_handle_debug);
 646#endif
 647
 648/**
 649 * acpi_evaluation_failure_warn - Log evaluation failure warning.
 650 * @handle: Parent object handle.
 651 * @name: Name of the object whose evaluation has failed.
 652 * @status: Status value returned by the failing object evaluation.
 653 */
 654void acpi_evaluation_failure_warn(acpi_handle handle, const char *name,
 655				  acpi_status status)
 656{
 657	acpi_handle_warn(handle, "%s evaluation failed: %s\n", name,
 658			 acpi_format_exception(status));
 659}
 660EXPORT_SYMBOL_GPL(acpi_evaluation_failure_warn);
 661
 662/**
 663 * acpi_has_method: Check whether @handle has a method named @name
 664 * @handle: ACPI device handle
 665 * @name: name of object or method
 666 *
 667 * Check whether @handle has a method named @name.
 668 */
 669bool acpi_has_method(acpi_handle handle, char *name)
 670{
 671	acpi_handle tmp;
 672
 673	return ACPI_SUCCESS(acpi_get_handle(handle, name, &tmp));
 674}
 675EXPORT_SYMBOL(acpi_has_method);
 676
 677acpi_status acpi_execute_simple_method(acpi_handle handle, char *method,
 678				       u64 arg)
 679{
 680	union acpi_object obj = { .type = ACPI_TYPE_INTEGER };
 681	struct acpi_object_list arg_list = { .count = 1, .pointer = &obj, };
 682
 683	obj.integer.value = arg;
 684
 685	return acpi_evaluate_object(handle, method, &arg_list, NULL);
 686}
 687EXPORT_SYMBOL(acpi_execute_simple_method);
 688
 689/**
 690 * acpi_evaluate_ej0: Evaluate _EJ0 method for hotplug operations
 691 * @handle: ACPI device handle
 692 *
 693 * Evaluate device's _EJ0 method for hotplug operations.
 694 */
 695acpi_status acpi_evaluate_ej0(acpi_handle handle)
 696{
 697	acpi_status status;
 698
 699	status = acpi_execute_simple_method(handle, "_EJ0", 1);
 700	if (status == AE_NOT_FOUND)
 701		acpi_handle_warn(handle, "No _EJ0 support for device\n");
 702	else if (ACPI_FAILURE(status))
 703		acpi_handle_warn(handle, "Eject failed (0x%x)\n", status);
 704
 705	return status;
 706}
 707
 708/**
 709 * acpi_evaluate_lck: Evaluate _LCK method to lock/unlock device
 710 * @handle: ACPI device handle
 711 * @lock: lock device if non-zero, otherwise unlock device
 712 *
 713 * Evaluate device's _LCK method if present to lock/unlock device
 714 */
 715acpi_status acpi_evaluate_lck(acpi_handle handle, int lock)
 716{
 717	acpi_status status;
 718
 719	status = acpi_execute_simple_method(handle, "_LCK", !!lock);
 720	if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {
 721		if (lock)
 722			acpi_handle_warn(handle,
 723				"Locking device failed (0x%x)\n", status);
 724		else
 725			acpi_handle_warn(handle,
 726				"Unlocking device failed (0x%x)\n", status);
 727	}
 728
 729	return status;
 730}
 731
 732/**
 733 * acpi_evaluate_reg: Evaluate _REG method to register OpRegion presence
 734 * @handle: ACPI device handle
 735 * @space_id: ACPI address space id to register OpRegion presence for
 736 * @function: Parameter to pass to _REG one of ACPI_REG_CONNECT or
 737 *            ACPI_REG_DISCONNECT
 738 *
 739 * Evaluate device's _REG method to register OpRegion presence.
 740 */
 741acpi_status acpi_evaluate_reg(acpi_handle handle, u8 space_id, u32 function)
 742{
 743	struct acpi_object_list arg_list;
 744	union acpi_object params[2];
 745
 746	params[0].type = ACPI_TYPE_INTEGER;
 747	params[0].integer.value = space_id;
 748	params[1].type = ACPI_TYPE_INTEGER;
 749	params[1].integer.value = function;
 750	arg_list.count = 2;
 751	arg_list.pointer = params;
 752
 753	return acpi_evaluate_object(handle, "_REG", &arg_list, NULL);
 754}
 755EXPORT_SYMBOL(acpi_evaluate_reg);
 756
 757/**
 758 * acpi_evaluate_dsm - evaluate device's _DSM method
 759 * @handle: ACPI device handle
 760 * @guid: GUID of requested functions, should be 16 bytes
 761 * @rev: revision number of requested function
 762 * @func: requested function number
 763 * @argv4: the function specific parameter
 764 *
 765 * Evaluate device's _DSM method with specified GUID, revision id and
 766 * function number. Caller needs to free the returned object.
 767 *
 768 * Though ACPI defines the fourth parameter for _DSM should be a package,
 769 * some old BIOSes do expect a buffer or an integer etc.
 770 */
 771union acpi_object *
 772acpi_evaluate_dsm(acpi_handle handle, const guid_t *guid, u64 rev, u64 func,
 773		  union acpi_object *argv4)
 774{
 775	acpi_status ret;
 776	struct acpi_buffer buf = {ACPI_ALLOCATE_BUFFER, NULL};
 777	union acpi_object params[4];
 778	struct acpi_object_list input = {
 779		.count = 4,
 780		.pointer = params,
 781	};
 782
 783	params[0].type = ACPI_TYPE_BUFFER;
 784	params[0].buffer.length = 16;
 785	params[0].buffer.pointer = (u8 *)guid;
 786	params[1].type = ACPI_TYPE_INTEGER;
 787	params[1].integer.value = rev;
 788	params[2].type = ACPI_TYPE_INTEGER;
 789	params[2].integer.value = func;
 790	if (argv4) {
 791		params[3] = *argv4;
 792	} else {
 793		params[3].type = ACPI_TYPE_PACKAGE;
 794		params[3].package.count = 0;
 795		params[3].package.elements = NULL;
 796	}
 797
 798	ret = acpi_evaluate_object(handle, "_DSM", &input, &buf);
 799	if (ACPI_SUCCESS(ret))
 800		return (union acpi_object *)buf.pointer;
 801
 802	if (ret != AE_NOT_FOUND)
 803		acpi_handle_warn(handle,
 804				 "failed to evaluate _DSM %pUb rev:%lld func:%lld (0x%x)\n",
 805				 guid, rev, func, ret);
 806
 807	return NULL;
 808}
 809EXPORT_SYMBOL(acpi_evaluate_dsm);
 810
 811/**
 812 * acpi_check_dsm - check if _DSM method supports requested functions.
 813 * @handle: ACPI device handle
 814 * @guid: GUID of requested functions, should be 16 bytes at least
 815 * @rev: revision number of requested functions
 816 * @funcs: bitmap of requested functions
 817 *
 818 * Evaluate device's _DSM method to check whether it supports requested
 819 * functions. Currently only support 64 functions at maximum, should be
 820 * enough for now.
 821 */
 822bool acpi_check_dsm(acpi_handle handle, const guid_t *guid, u64 rev, u64 funcs)
 823{
 824	int i;
 825	u64 mask = 0;
 826	union acpi_object *obj;
 827
 828	if (funcs == 0)
 829		return false;
 830
 831	obj = acpi_evaluate_dsm(handle, guid, rev, 0, NULL);
 832	if (!obj)
 833		return false;
 834
 835	/* For compatibility, old BIOSes may return an integer */
 836	if (obj->type == ACPI_TYPE_INTEGER)
 837		mask = obj->integer.value;
 838	else if (obj->type == ACPI_TYPE_BUFFER)
 839		for (i = 0; i < obj->buffer.length && i < 8; i++)
 840			mask |= (((u64)obj->buffer.pointer[i]) << (i * 8));
 841	ACPI_FREE(obj);
 842
 843	/*
 844	 * Bit 0 indicates whether there's support for any functions other than
 845	 * function 0 for the specified GUID and revision.
 846	 */
 847	if ((mask & 0x1) && (mask & funcs) == funcs)
 848		return true;
 849
 850	return false;
 851}
 852EXPORT_SYMBOL(acpi_check_dsm);
 853
 854/**
 855 * acpi_dev_uid_to_integer - treat ACPI device _UID as integer
 856 * @adev: ACPI device to get _UID from
 857 * @integer: output buffer for integer
 
 858 *
 859 * Considers _UID as integer and converts it to @integer.
 860 *
 861 * Returns 0 on success, or negative error code otherwise.
 862 */
 863int acpi_dev_uid_to_integer(struct acpi_device *adev, u64 *integer)
 
 864{
 865	const char *uid;
 
 866
 867	if (!adev)
 868		return -ENODEV;
 869
 870	uid = acpi_device_uid(adev);
 871	if (!uid)
 872		return -ENODATA;
 873
 874	return kstrtou64(uid, 0, integer);
 875}
 876EXPORT_SYMBOL(acpi_dev_uid_to_integer);
 877
 878/**
 879 * acpi_dev_found - Detect presence of a given ACPI device in the namespace.
 880 * @hid: Hardware ID of the device.
 881 *
 882 * Return %true if the device was present at the moment of invocation.
 883 * Note that if the device is pluggable, it may since have disappeared.
 884 *
 885 * For this function to work, acpi_bus_scan() must have been executed
 886 * which happens in the subsys_initcall() subsection. Hence, do not
 887 * call from a subsys_initcall() or earlier (use acpi_get_devices()
 888 * instead). Calling from module_init() is fine (which is synonymous
 889 * with device_initcall()).
 890 */
 891bool acpi_dev_found(const char *hid)
 892{
 893	struct acpi_device_bus_id *acpi_device_bus_id;
 894	bool found = false;
 895
 896	mutex_lock(&acpi_device_lock);
 897	list_for_each_entry(acpi_device_bus_id, &acpi_bus_id_list, node)
 898		if (!strcmp(acpi_device_bus_id->bus_id, hid)) {
 899			found = true;
 900			break;
 901		}
 902	mutex_unlock(&acpi_device_lock);
 903
 904	return found;
 905}
 906EXPORT_SYMBOL(acpi_dev_found);
 907
 908struct acpi_dev_match_info {
 909	struct acpi_device_id hid[2];
 910	const char *uid;
 911	s64 hrv;
 912};
 913
 914static int acpi_dev_match_cb(struct device *dev, const void *data)
 915{
 916	struct acpi_device *adev = to_acpi_device(dev);
 917	const struct acpi_dev_match_info *match = data;
 918	unsigned long long hrv;
 919	acpi_status status;
 920
 921	if (acpi_match_device_ids(adev, match->hid))
 922		return 0;
 923
 924	if (match->uid && !acpi_dev_uid_match(adev, match->uid))
 
 925		return 0;
 926
 927	if (match->hrv == -1)
 928		return 1;
 929
 930	status = acpi_evaluate_integer(adev->handle, "_HRV", NULL, &hrv);
 931	if (ACPI_FAILURE(status))
 932		return 0;
 933
 934	return hrv == match->hrv;
 935}
 936
 937/**
 938 * acpi_dev_present - Detect that a given ACPI device is present
 939 * @hid: Hardware ID of the device.
 940 * @uid: Unique ID of the device, pass NULL to not check _UID
 941 * @hrv: Hardware Revision of the device, pass -1 to not check _HRV
 942 *
 943 * Return %true if a matching device was present at the moment of invocation.
 944 * Note that if the device is pluggable, it may since have disappeared.
 945 *
 946 * Note that unlike acpi_dev_found() this function checks the status
 947 * of the device. So for devices which are present in the DSDT, but
 948 * which are disabled (their _STA callback returns 0) this function
 949 * will return false.
 950 *
 951 * For this function to work, acpi_bus_scan() must have been executed
 952 * which happens in the subsys_initcall() subsection. Hence, do not
 953 * call from a subsys_initcall() or earlier (use acpi_get_devices()
 954 * instead). Calling from module_init() is fine (which is synonymous
 955 * with device_initcall()).
 956 */
 957bool acpi_dev_present(const char *hid, const char *uid, s64 hrv)
 958{
 959	struct acpi_dev_match_info match = {};
 960	struct device *dev;
 961
 962	strscpy(match.hid[0].id, hid, sizeof(match.hid[0].id));
 963	match.uid = uid;
 964	match.hrv = hrv;
 965
 966	dev = bus_find_device(&acpi_bus_type, NULL, &match, acpi_dev_match_cb);
 967	put_device(dev);
 968	return !!dev;
 969}
 970EXPORT_SYMBOL(acpi_dev_present);
 971
 972/**
 973 * acpi_dev_get_next_match_dev - Return the next match of ACPI device
 974 * @adev: Pointer to the previous ACPI device matching this @hid, @uid and @hrv
 975 * @hid: Hardware ID of the device.
 976 * @uid: Unique ID of the device, pass NULL to not check _UID
 977 * @hrv: Hardware Revision of the device, pass -1 to not check _HRV
 978 *
 979 * Return the next match of ACPI device if another matching device was present
 980 * at the moment of invocation, or NULL otherwise.
 981 *
 982 * The caller is responsible for invoking acpi_dev_put() on the returned device.
 983 * On the other hand the function invokes  acpi_dev_put() on the given @adev
 984 * assuming that its reference counter had been increased beforehand.
 985 *
 986 * See additional information in acpi_dev_present() as well.
 987 */
 988struct acpi_device *
 989acpi_dev_get_next_match_dev(struct acpi_device *adev, const char *hid, const char *uid, s64 hrv)
 990{
 991	struct device *start = adev ? &adev->dev : NULL;
 992	struct acpi_dev_match_info match = {};
 993	struct device *dev;
 994
 995	strscpy(match.hid[0].id, hid, sizeof(match.hid[0].id));
 996	match.uid = uid;
 997	match.hrv = hrv;
 998
 999	dev = bus_find_device(&acpi_bus_type, start, &match, acpi_dev_match_cb);
1000	acpi_dev_put(adev);
1001	return dev ? to_acpi_device(dev) : NULL;
1002}
1003EXPORT_SYMBOL(acpi_dev_get_next_match_dev);
1004
1005/**
1006 * acpi_dev_get_first_match_dev - Return the first match of ACPI device
1007 * @hid: Hardware ID of the device.
1008 * @uid: Unique ID of the device, pass NULL to not check _UID
1009 * @hrv: Hardware Revision of the device, pass -1 to not check _HRV
1010 *
1011 * Return the first match of ACPI device if a matching device was present
1012 * at the moment of invocation, or NULL otherwise.
1013 *
1014 * The caller is responsible for invoking acpi_dev_put() on the returned device.
1015 *
1016 * See additional information in acpi_dev_present() as well.
1017 */
1018struct acpi_device *
1019acpi_dev_get_first_match_dev(const char *hid, const char *uid, s64 hrv)
1020{
1021	return acpi_dev_get_next_match_dev(NULL, hid, uid, hrv);
1022}
1023EXPORT_SYMBOL(acpi_dev_get_first_match_dev);
1024
1025/**
1026 * acpi_reduced_hardware - Return if this is an ACPI-reduced-hw machine
1027 *
1028 * Return true when running on an ACPI-reduced-hw machine, false otherwise.
1029 */
1030bool acpi_reduced_hardware(void)
1031{
1032	return acpi_gbl_reduced_hardware;
1033}
1034EXPORT_SYMBOL_GPL(acpi_reduced_hardware);
1035
1036/*
1037 * acpi_backlight= handling, this is done here rather then in video_detect.c
1038 * because __setup cannot be used in modules.
1039 */
1040char acpi_video_backlight_string[16];
1041EXPORT_SYMBOL(acpi_video_backlight_string);
1042
1043static int __init acpi_backlight(char *str)
1044{
1045	strscpy(acpi_video_backlight_string, str,
1046		sizeof(acpi_video_backlight_string));
1047	return 1;
1048}
1049__setup("acpi_backlight=", acpi_backlight);
1050
1051/**
1052 * acpi_match_platform_list - Check if the system matches with a given list
1053 * @plat: pointer to acpi_platform_list table terminated by a NULL entry
1054 *
1055 * Return the matched index if the system is found in the platform list.
1056 * Otherwise, return a negative error code.
1057 */
1058int acpi_match_platform_list(const struct acpi_platform_list *plat)
1059{
1060	struct acpi_table_header hdr;
1061	int idx = 0;
1062
1063	if (acpi_disabled)
1064		return -ENODEV;
1065
1066	for (; plat->oem_id[0]; plat++, idx++) {
1067		if (ACPI_FAILURE(acpi_get_table_header(plat->table, 0, &hdr)))
1068			continue;
1069
1070		if (strncmp(plat->oem_id, hdr.oem_id, ACPI_OEM_ID_SIZE))
1071			continue;
1072
1073		if (strncmp(plat->oem_table_id, hdr.oem_table_id, ACPI_OEM_TABLE_ID_SIZE))
1074			continue;
1075
1076		if ((plat->pred == all_versions) ||
1077		    (plat->pred == less_than_or_equal && hdr.oem_revision <= plat->oem_revision) ||
1078		    (plat->pred == greater_than_or_equal && hdr.oem_revision >= plat->oem_revision) ||
1079		    (plat->pred == equal && hdr.oem_revision == plat->oem_revision))
1080			return idx;
1081	}
1082
1083	return -ENODEV;
1084}
1085EXPORT_SYMBOL(acpi_match_platform_list);