xref: /linux/drivers/acpi/utils.c (revision 42422993cf28d456778ee9168d73758ec037cd51)
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    -------------------------------------------------------------------------- */
26 static 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 
31 acpi_status
32 acpi_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 
244 EXPORT_SYMBOL(acpi_extract_package);
245 
246 acpi_status
247 acpi_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 
278 EXPORT_SYMBOL(acpi_evaluate_integer);
279 
280 int acpi_get_local_address(acpi_handle handle, u32 *addr)
281 {
282 	unsigned long long adr;
283 	acpi_status status;
284 
285 	status = acpi_evaluate_integer(handle, METHOD_NAME__ADR, NULL, &adr);
286 	if (ACPI_FAILURE(status))
287 		return -ENODATA;
288 
289 	*addr = (u32)adr;
290 	return 0;
291 }
292 EXPORT_SYMBOL(acpi_get_local_address);
293 
294 #define ACPI_MAX_SUB_BUF_SIZE	9
295 
296 const char *acpi_get_subsystem_id(acpi_handle handle)
297 {
298 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
299 	union acpi_object *obj;
300 	acpi_status status;
301 	const char *sub;
302 	size_t len;
303 
304 	status = acpi_evaluate_object(handle, METHOD_NAME__SUB, NULL, &buffer);
305 	if (ACPI_FAILURE(status)) {
306 		acpi_handle_debug(handle, "Reading ACPI _SUB failed: %#x\n", status);
307 		return ERR_PTR(-ENODATA);
308 	}
309 
310 	obj = buffer.pointer;
311 	if (obj->type == ACPI_TYPE_STRING) {
312 		len = strlen(obj->string.pointer);
313 		if (len < ACPI_MAX_SUB_BUF_SIZE && len > 0) {
314 			sub = kstrdup(obj->string.pointer, GFP_KERNEL);
315 			if (!sub)
316 				sub = ERR_PTR(-ENOMEM);
317 		} else {
318 			acpi_handle_err(handle, "ACPI _SUB Length %zu is Invalid\n", len);
319 			sub = ERR_PTR(-ENODATA);
320 		}
321 	} else {
322 		acpi_handle_warn(handle, "Warning ACPI _SUB did not return a string\n");
323 		sub = ERR_PTR(-ENODATA);
324 	}
325 
326 	acpi_os_free(buffer.pointer);
327 
328 	return sub;
329 }
330 EXPORT_SYMBOL_GPL(acpi_get_subsystem_id);
331 
332 acpi_status
333 acpi_evaluate_reference(acpi_handle handle,
334 			acpi_string pathname,
335 			struct acpi_object_list *arguments,
336 			struct acpi_handle_list *list)
337 {
338 	acpi_status status = AE_OK;
339 	union acpi_object *package = NULL;
340 	union acpi_object *element = NULL;
341 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
342 	u32 i = 0;
343 
344 
345 	if (!list)
346 		return AE_BAD_PARAMETER;
347 
348 	/* Evaluate object. */
349 
350 	status = acpi_evaluate_object(handle, pathname, arguments, &buffer);
351 	if (ACPI_FAILURE(status))
352 		goto end;
353 
354 	package = buffer.pointer;
355 
356 	if ((buffer.length == 0) || !package) {
357 		status = AE_BAD_DATA;
358 		acpi_util_eval_error(handle, pathname, status);
359 		goto end;
360 	}
361 	if (package->type != ACPI_TYPE_PACKAGE) {
362 		status = AE_BAD_DATA;
363 		acpi_util_eval_error(handle, pathname, status);
364 		goto end;
365 	}
366 	if (!package->package.count) {
367 		status = AE_BAD_DATA;
368 		acpi_util_eval_error(handle, pathname, status);
369 		goto end;
370 	}
371 
372 	list->handles = kcalloc(package->package.count, sizeof(*list->handles), GFP_KERNEL);
373 	if (!list->handles) {
374 		kfree(package);
375 		return AE_NO_MEMORY;
376 	}
377 	list->count = package->package.count;
378 
379 	/* Extract package data. */
380 
381 	for (i = 0; i < list->count; i++) {
382 
383 		element = &(package->package.elements[i]);
384 
385 		if (element->type != ACPI_TYPE_LOCAL_REFERENCE) {
386 			status = AE_BAD_DATA;
387 			acpi_util_eval_error(handle, pathname, status);
388 			break;
389 		}
390 
391 		if (!element->reference.handle) {
392 			status = AE_NULL_ENTRY;
393 			acpi_util_eval_error(handle, pathname, status);
394 			break;
395 		}
396 		/* Get the  acpi_handle. */
397 
398 		list->handles[i] = element->reference.handle;
399 		acpi_handle_debug(list->handles[i], "Found in reference list\n");
400 	}
401 
402 	if (ACPI_FAILURE(status)) {
403 		list->count = 0;
404 		kfree(list->handles);
405 		list->handles = NULL;
406 	}
407 
408 end:
409 	kfree(buffer.pointer);
410 
411 	return status;
412 }
413 
414 EXPORT_SYMBOL(acpi_evaluate_reference);
415 
416 /**
417  * acpi_handle_list_equal - Check if two ACPI handle lists are the same
418  * @list1: First list to compare.
419  * @list2: Second list to compare.
420  *
421  * Return true if the given ACPI handle lists are of the same size and
422  * contain the same ACPI handles in the same order.  Otherwise, return false.
423  */
424 bool acpi_handle_list_equal(struct acpi_handle_list *list1,
425 			    struct acpi_handle_list *list2)
426 {
427 	return list1->count == list2->count &&
428 		!memcmp(list1->handles, list2->handles,
429 		        list1->count * sizeof(acpi_handle));
430 }
431 EXPORT_SYMBOL_GPL(acpi_handle_list_equal);
432 
433 /**
434  * acpi_handle_list_replace - Replace one ACPI handle list with another
435  * @dst: ACPI handle list to replace.
436  * @src: Source ACPI handle list.
437  *
438  * Free the handles table in @dst, move the handles table from @src to @dst,
439  * copy count from @src to @dst and clear @src.
440  */
441 void acpi_handle_list_replace(struct acpi_handle_list *dst,
442 			      struct acpi_handle_list *src)
443 {
444 	if (dst->count)
445 		kfree(dst->handles);
446 
447 	dst->count = src->count;
448 	dst->handles = src->handles;
449 
450 	src->handles = NULL;
451 	src->count = 0;
452 }
453 EXPORT_SYMBOL_GPL(acpi_handle_list_replace);
454 
455 /**
456  * acpi_handle_list_free - Free the handles table in an ACPI handle list
457  * @list: ACPI handle list to free.
458  *
459  * Free the handles table in @list and clear its count field.
460  */
461 void acpi_handle_list_free(struct acpi_handle_list *list)
462 {
463 	if (!list->count)
464 		return;
465 
466 	kfree(list->handles);
467 	list->count = 0;
468 }
469 EXPORT_SYMBOL_GPL(acpi_handle_list_free);
470 
471 acpi_status
472 acpi_get_physical_device_location(acpi_handle handle, struct acpi_pld_info **pld)
473 {
474 	acpi_status status;
475 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
476 	union acpi_object *output;
477 
478 	status = acpi_evaluate_object(handle, "_PLD", NULL, &buffer);
479 
480 	if (ACPI_FAILURE(status))
481 		return status;
482 
483 	output = buffer.pointer;
484 
485 	if (!output || output->type != ACPI_TYPE_PACKAGE
486 	    || !output->package.count
487 	    || output->package.elements[0].type != ACPI_TYPE_BUFFER
488 	    || output->package.elements[0].buffer.length < ACPI_PLD_REV1_BUFFER_SIZE) {
489 		status = AE_TYPE;
490 		goto out;
491 	}
492 
493 	status = acpi_decode_pld_buffer(
494 			output->package.elements[0].buffer.pointer,
495 			output->package.elements[0].buffer.length,
496 			pld);
497 
498 out:
499 	kfree(buffer.pointer);
500 	return status;
501 }
502 EXPORT_SYMBOL(acpi_get_physical_device_location);
503 
504 /**
505  * acpi_evaluate_ost: Evaluate _OST for hotplug operations
506  * @handle: ACPI device handle
507  * @source_event: source event code
508  * @status_code: status code
509  * @status_buf: optional detailed information (NULL if none)
510  *
511  * Evaluate _OST for hotplug operations. All ACPI hotplug handlers
512  * must call this function when evaluating _OST for hotplug operations.
513  * When the platform does not support _OST, this function has no effect.
514  */
515 acpi_status
516 acpi_evaluate_ost(acpi_handle handle, u32 source_event, u32 status_code,
517 		  struct acpi_buffer *status_buf)
518 {
519 	union acpi_object params[3] = {
520 		{.type = ACPI_TYPE_INTEGER,},
521 		{.type = ACPI_TYPE_INTEGER,},
522 		{.type = ACPI_TYPE_BUFFER,}
523 	};
524 	struct acpi_object_list arg_list = {3, params};
525 
526 	params[0].integer.value = source_event;
527 	params[1].integer.value = status_code;
528 	if (status_buf != NULL) {
529 		params[2].buffer.pointer = status_buf->pointer;
530 		params[2].buffer.length = status_buf->length;
531 	} else {
532 		params[2].buffer.pointer = NULL;
533 		params[2].buffer.length = 0;
534 	}
535 
536 	return acpi_evaluate_object(handle, "_OST", &arg_list, NULL);
537 }
538 EXPORT_SYMBOL(acpi_evaluate_ost);
539 
540 /**
541  * acpi_handle_path: Return the object path of handle
542  * @handle: ACPI device handle
543  *
544  * Caller must free the returned buffer
545  */
546 static char *acpi_handle_path(acpi_handle handle)
547 {
548 	struct acpi_buffer buffer = {
549 		.length = ACPI_ALLOCATE_BUFFER,
550 		.pointer = NULL
551 	};
552 
553 	if (in_interrupt() ||
554 	    acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer) != AE_OK)
555 		return NULL;
556 	return buffer.pointer;
557 }
558 
559 /**
560  * acpi_handle_printk: Print message with ACPI prefix and object path
561  * @level: log level
562  * @handle: ACPI device handle
563  * @fmt: format string
564  *
565  * This function is called through acpi_handle_<level> macros and prints
566  * a message with ACPI prefix and object path.  This function acquires
567  * the global namespace mutex to obtain an object path.  In interrupt
568  * context, it shows the object path as <n/a>.
569  */
570 void
571 acpi_handle_printk(const char *level, acpi_handle handle, const char *fmt, ...)
572 {
573 	struct va_format vaf;
574 	va_list args;
575 	const char *path;
576 
577 	va_start(args, fmt);
578 	vaf.fmt = fmt;
579 	vaf.va = &args;
580 
581 	path = acpi_handle_path(handle);
582 	printk("%sACPI: %s: %pV", level, path ? path : "<n/a>", &vaf);
583 
584 	va_end(args);
585 	kfree(path);
586 }
587 EXPORT_SYMBOL(acpi_handle_printk);
588 
589 #if defined(CONFIG_DYNAMIC_DEBUG)
590 /**
591  * __acpi_handle_debug: pr_debug with ACPI prefix and object path
592  * @descriptor: Dynamic Debug descriptor
593  * @handle: ACPI device handle
594  * @fmt: format string
595  *
596  * This function is called through acpi_handle_debug macro and debug
597  * prints a message with ACPI prefix and object path. This function
598  * acquires the global namespace mutex to obtain an object path.  In
599  * interrupt context, it shows the object path as <n/a>.
600  */
601 void
602 __acpi_handle_debug(struct _ddebug *descriptor, acpi_handle handle,
603 		    const char *fmt, ...)
604 {
605 	struct va_format vaf;
606 	va_list args;
607 	const char *path;
608 
609 	va_start(args, fmt);
610 	vaf.fmt = fmt;
611 	vaf.va = &args;
612 
613 	path = acpi_handle_path(handle);
614 	__dynamic_pr_debug(descriptor, "ACPI: %s: %pV", path ? path : "<n/a>", &vaf);
615 
616 	va_end(args);
617 	kfree(path);
618 }
619 EXPORT_SYMBOL(__acpi_handle_debug);
620 #endif
621 
622 /**
623  * acpi_evaluation_failure_warn - Log evaluation failure warning.
624  * @handle: Parent object handle.
625  * @name: Name of the object whose evaluation has failed.
626  * @status: Status value returned by the failing object evaluation.
627  */
628 void acpi_evaluation_failure_warn(acpi_handle handle, const char *name,
629 				  acpi_status status)
630 {
631 	acpi_handle_warn(handle, "%s evaluation failed: %s\n", name,
632 			 acpi_format_exception(status));
633 }
634 EXPORT_SYMBOL_GPL(acpi_evaluation_failure_warn);
635 
636 /**
637  * acpi_has_method: Check whether @handle has a method named @name
638  * @handle: ACPI device handle
639  * @name: name of object or method
640  *
641  * Check whether @handle has a method named @name.
642  */
643 bool acpi_has_method(acpi_handle handle, char *name)
644 {
645 	acpi_handle tmp;
646 
647 	return ACPI_SUCCESS(acpi_get_handle(handle, name, &tmp));
648 }
649 EXPORT_SYMBOL(acpi_has_method);
650 
651 acpi_status acpi_execute_simple_method(acpi_handle handle, char *method,
652 				       u64 arg)
653 {
654 	union acpi_object obj = { .type = ACPI_TYPE_INTEGER };
655 	struct acpi_object_list arg_list = { .count = 1, .pointer = &obj, };
656 
657 	obj.integer.value = arg;
658 
659 	return acpi_evaluate_object(handle, method, &arg_list, NULL);
660 }
661 EXPORT_SYMBOL(acpi_execute_simple_method);
662 
663 /**
664  * acpi_evaluate_ej0: Evaluate _EJ0 method for hotplug operations
665  * @handle: ACPI device handle
666  *
667  * Evaluate device's _EJ0 method for hotplug operations.
668  */
669 acpi_status acpi_evaluate_ej0(acpi_handle handle)
670 {
671 	acpi_status status;
672 
673 	status = acpi_execute_simple_method(handle, "_EJ0", 1);
674 	if (status == AE_NOT_FOUND)
675 		acpi_handle_warn(handle, "No _EJ0 support for device\n");
676 	else if (ACPI_FAILURE(status))
677 		acpi_handle_warn(handle, "Eject failed (0x%x)\n", status);
678 
679 	return status;
680 }
681 
682 /**
683  * acpi_evaluate_lck: Evaluate _LCK method to lock/unlock device
684  * @handle: ACPI device handle
685  * @lock: lock device if non-zero, otherwise unlock device
686  *
687  * Evaluate device's _LCK method if present to lock/unlock device
688  */
689 acpi_status acpi_evaluate_lck(acpi_handle handle, int lock)
690 {
691 	acpi_status status;
692 
693 	status = acpi_execute_simple_method(handle, "_LCK", !!lock);
694 	if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {
695 		if (lock)
696 			acpi_handle_warn(handle,
697 				"Locking device failed (0x%x)\n", status);
698 		else
699 			acpi_handle_warn(handle,
700 				"Unlocking device failed (0x%x)\n", status);
701 	}
702 
703 	return status;
704 }
705 
706 /**
707  * acpi_evaluate_reg: Evaluate _REG method to register OpRegion presence
708  * @handle: ACPI device handle
709  * @space_id: ACPI address space id to register OpRegion presence for
710  * @function: Parameter to pass to _REG one of ACPI_REG_CONNECT or
711  *            ACPI_REG_DISCONNECT
712  *
713  * Evaluate device's _REG method to register OpRegion presence.
714  */
715 acpi_status acpi_evaluate_reg(acpi_handle handle, u8 space_id, u32 function)
716 {
717 	struct acpi_object_list arg_list;
718 	union acpi_object params[2];
719 
720 	params[0].type = ACPI_TYPE_INTEGER;
721 	params[0].integer.value = space_id;
722 	params[1].type = ACPI_TYPE_INTEGER;
723 	params[1].integer.value = function;
724 	arg_list.count = 2;
725 	arg_list.pointer = params;
726 
727 	return acpi_evaluate_object(handle, "_REG", &arg_list, NULL);
728 }
729 EXPORT_SYMBOL(acpi_evaluate_reg);
730 
731 /**
732  * acpi_evaluate_dsm - evaluate device's _DSM method
733  * @handle: ACPI device handle
734  * @guid: GUID of requested functions, should be 16 bytes
735  * @rev: revision number of requested function
736  * @func: requested function number
737  * @argv4: the function specific parameter
738  *
739  * Evaluate device's _DSM method with specified GUID, revision id and
740  * function number. Caller needs to free the returned object.
741  *
742  * Though ACPI defines the fourth parameter for _DSM should be a package,
743  * some old BIOSes do expect a buffer or an integer etc.
744  */
745 union acpi_object *
746 acpi_evaluate_dsm(acpi_handle handle, const guid_t *guid, u64 rev, u64 func,
747 		  union acpi_object *argv4)
748 {
749 	acpi_status ret;
750 	struct acpi_buffer buf = {ACPI_ALLOCATE_BUFFER, NULL};
751 	union acpi_object params[4];
752 	struct acpi_object_list input = {
753 		.count = 4,
754 		.pointer = params,
755 	};
756 
757 	params[0].type = ACPI_TYPE_BUFFER;
758 	params[0].buffer.length = 16;
759 	params[0].buffer.pointer = (u8 *)guid;
760 	params[1].type = ACPI_TYPE_INTEGER;
761 	params[1].integer.value = rev;
762 	params[2].type = ACPI_TYPE_INTEGER;
763 	params[2].integer.value = func;
764 	if (argv4) {
765 		params[3] = *argv4;
766 	} else {
767 		params[3].type = ACPI_TYPE_PACKAGE;
768 		params[3].package.count = 0;
769 		params[3].package.elements = NULL;
770 	}
771 
772 	ret = acpi_evaluate_object(handle, "_DSM", &input, &buf);
773 	if (ACPI_SUCCESS(ret))
774 		return (union acpi_object *)buf.pointer;
775 
776 	if (ret != AE_NOT_FOUND)
777 		acpi_handle_warn(handle,
778 				 "failed to evaluate _DSM %pUb (0x%x)\n", guid, ret);
779 
780 	return NULL;
781 }
782 EXPORT_SYMBOL(acpi_evaluate_dsm);
783 
784 /**
785  * acpi_check_dsm - check if _DSM method supports requested functions.
786  * @handle: ACPI device handle
787  * @guid: GUID of requested functions, should be 16 bytes at least
788  * @rev: revision number of requested functions
789  * @funcs: bitmap of requested functions
790  *
791  * Evaluate device's _DSM method to check whether it supports requested
792  * functions. Currently only support 64 functions at maximum, should be
793  * enough for now.
794  */
795 bool acpi_check_dsm(acpi_handle handle, const guid_t *guid, u64 rev, u64 funcs)
796 {
797 	int i;
798 	u64 mask = 0;
799 	union acpi_object *obj;
800 
801 	if (funcs == 0)
802 		return false;
803 
804 	obj = acpi_evaluate_dsm(handle, guid, rev, 0, NULL);
805 	if (!obj)
806 		return false;
807 
808 	/* For compatibility, old BIOSes may return an integer */
809 	if (obj->type == ACPI_TYPE_INTEGER)
810 		mask = obj->integer.value;
811 	else if (obj->type == ACPI_TYPE_BUFFER)
812 		for (i = 0; i < obj->buffer.length && i < 8; i++)
813 			mask |= (((u64)obj->buffer.pointer[i]) << (i * 8));
814 	ACPI_FREE(obj);
815 
816 	/*
817 	 * Bit 0 indicates whether there's support for any functions other than
818 	 * function 0 for the specified GUID and revision.
819 	 */
820 	if ((mask & 0x1) && (mask & funcs) == funcs)
821 		return true;
822 
823 	return false;
824 }
825 EXPORT_SYMBOL(acpi_check_dsm);
826 
827 /**
828  * acpi_dev_uid_match - Match device by supplied UID
829  * @adev: ACPI device to match.
830  * @uid2: Unique ID of the device.
831  *
832  * Matches UID in @adev with given @uid2.
833  *
834  * Returns:
835  *  - %true if matches.
836  *  - %false otherwise.
837  */
838 bool acpi_dev_uid_match(struct acpi_device *adev, const char *uid2)
839 {
840 	const char *uid1 = acpi_device_uid(adev);
841 
842 	return uid1 && uid2 && !strcmp(uid1, uid2);
843 }
844 EXPORT_SYMBOL_GPL(acpi_dev_uid_match);
845 
846 /**
847  * acpi_dev_hid_uid_match - Match device by supplied HID and UID
848  * @adev: ACPI device to match.
849  * @hid2: Hardware ID of the device.
850  * @uid2: Unique ID of the device, pass NULL to not check _UID.
851  *
852  * Matches HID and UID in @adev with given @hid2 and @uid2. Absence of @uid2
853  * will be treated as a match. If user wants to validate @uid2, it should be
854  * done before calling this function.
855  *
856  * Returns:
857  *  - %true if matches or @uid2 is NULL.
858  *  - %false otherwise.
859  */
860 bool acpi_dev_hid_uid_match(struct acpi_device *adev,
861 			    const char *hid2, const char *uid2)
862 {
863 	const char *hid1 = acpi_device_hid(adev);
864 
865 	if (strcmp(hid1, hid2))
866 		return false;
867 
868 	if (!uid2)
869 		return true;
870 
871 	return acpi_dev_uid_match(adev, uid2);
872 }
873 EXPORT_SYMBOL(acpi_dev_hid_uid_match);
874 
875 /**
876  * acpi_dev_uid_to_integer - treat ACPI device _UID as integer
877  * @adev: ACPI device to get _UID from
878  * @integer: output buffer for integer
879  *
880  * Considers _UID as integer and converts it to @integer.
881  *
882  * Returns 0 on success, or negative error code otherwise.
883  */
884 int acpi_dev_uid_to_integer(struct acpi_device *adev, u64 *integer)
885 {
886 	const char *uid;
887 
888 	if (!adev)
889 		return -ENODEV;
890 
891 	uid = acpi_device_uid(adev);
892 	if (!uid)
893 		return -ENODATA;
894 
895 	return kstrtou64(uid, 0, integer);
896 }
897 EXPORT_SYMBOL(acpi_dev_uid_to_integer);
898 
899 /**
900  * acpi_dev_found - Detect presence of a given ACPI device in the namespace.
901  * @hid: Hardware ID of the device.
902  *
903  * Return %true if the device was present at the moment of invocation.
904  * Note that if the device is pluggable, it may since have disappeared.
905  *
906  * For this function to work, acpi_bus_scan() must have been executed
907  * which happens in the subsys_initcall() subsection. Hence, do not
908  * call from a subsys_initcall() or earlier (use acpi_get_devices()
909  * instead). Calling from module_init() is fine (which is synonymous
910  * with device_initcall()).
911  */
912 bool acpi_dev_found(const char *hid)
913 {
914 	struct acpi_device_bus_id *acpi_device_bus_id;
915 	bool found = false;
916 
917 	mutex_lock(&acpi_device_lock);
918 	list_for_each_entry(acpi_device_bus_id, &acpi_bus_id_list, node)
919 		if (!strcmp(acpi_device_bus_id->bus_id, hid)) {
920 			found = true;
921 			break;
922 		}
923 	mutex_unlock(&acpi_device_lock);
924 
925 	return found;
926 }
927 EXPORT_SYMBOL(acpi_dev_found);
928 
929 struct acpi_dev_match_info {
930 	struct acpi_device_id hid[2];
931 	const char *uid;
932 	s64 hrv;
933 };
934 
935 static int acpi_dev_match_cb(struct device *dev, const void *data)
936 {
937 	struct acpi_device *adev = to_acpi_device(dev);
938 	const struct acpi_dev_match_info *match = data;
939 	unsigned long long hrv;
940 	acpi_status status;
941 
942 	if (acpi_match_device_ids(adev, match->hid))
943 		return 0;
944 
945 	if (match->uid && !acpi_dev_uid_match(adev, match->uid))
946 		return 0;
947 
948 	if (match->hrv == -1)
949 		return 1;
950 
951 	status = acpi_evaluate_integer(adev->handle, "_HRV", NULL, &hrv);
952 	if (ACPI_FAILURE(status))
953 		return 0;
954 
955 	return hrv == match->hrv;
956 }
957 
958 /**
959  * acpi_dev_present - Detect that a given ACPI device is present
960  * @hid: Hardware ID of the device.
961  * @uid: Unique ID of the device, pass NULL to not check _UID
962  * @hrv: Hardware Revision of the device, pass -1 to not check _HRV
963  *
964  * Return %true if a matching device was present at the moment of invocation.
965  * Note that if the device is pluggable, it may since have disappeared.
966  *
967  * Note that unlike acpi_dev_found() this function checks the status
968  * of the device. So for devices which are present in the DSDT, but
969  * which are disabled (their _STA callback returns 0) this function
970  * will return false.
971  *
972  * For this function to work, acpi_bus_scan() must have been executed
973  * which happens in the subsys_initcall() subsection. Hence, do not
974  * call from a subsys_initcall() or earlier (use acpi_get_devices()
975  * instead). Calling from module_init() is fine (which is synonymous
976  * with device_initcall()).
977  */
978 bool acpi_dev_present(const char *hid, const char *uid, s64 hrv)
979 {
980 	struct acpi_dev_match_info match = {};
981 	struct device *dev;
982 
983 	strscpy(match.hid[0].id, hid, sizeof(match.hid[0].id));
984 	match.uid = uid;
985 	match.hrv = hrv;
986 
987 	dev = bus_find_device(&acpi_bus_type, NULL, &match, acpi_dev_match_cb);
988 	put_device(dev);
989 	return !!dev;
990 }
991 EXPORT_SYMBOL(acpi_dev_present);
992 
993 /**
994  * acpi_dev_get_next_match_dev - Return the next match of ACPI device
995  * @adev: Pointer to the previous ACPI device matching this @hid, @uid and @hrv
996  * @hid: Hardware ID of the device.
997  * @uid: Unique ID of the device, pass NULL to not check _UID
998  * @hrv: Hardware Revision of the device, pass -1 to not check _HRV
999  *
1000  * Return the next match of ACPI device if another matching device was present
1001  * at the moment of invocation, or NULL otherwise.
1002  *
1003  * The caller is responsible for invoking acpi_dev_put() on the returned device.
1004  * On the other hand the function invokes  acpi_dev_put() on the given @adev
1005  * assuming that its reference counter had been increased beforehand.
1006  *
1007  * See additional information in acpi_dev_present() as well.
1008  */
1009 struct acpi_device *
1010 acpi_dev_get_next_match_dev(struct acpi_device *adev, const char *hid, const char *uid, s64 hrv)
1011 {
1012 	struct device *start = adev ? &adev->dev : NULL;
1013 	struct acpi_dev_match_info match = {};
1014 	struct device *dev;
1015 
1016 	strscpy(match.hid[0].id, hid, sizeof(match.hid[0].id));
1017 	match.uid = uid;
1018 	match.hrv = hrv;
1019 
1020 	dev = bus_find_device(&acpi_bus_type, start, &match, acpi_dev_match_cb);
1021 	acpi_dev_put(adev);
1022 	return dev ? to_acpi_device(dev) : NULL;
1023 }
1024 EXPORT_SYMBOL(acpi_dev_get_next_match_dev);
1025 
1026 /**
1027  * acpi_dev_get_first_match_dev - Return the first match of ACPI device
1028  * @hid: Hardware ID of the device.
1029  * @uid: Unique ID of the device, pass NULL to not check _UID
1030  * @hrv: Hardware Revision of the device, pass -1 to not check _HRV
1031  *
1032  * Return the first match of ACPI device if a matching device was present
1033  * at the moment of invocation, or NULL otherwise.
1034  *
1035  * The caller is responsible for invoking acpi_dev_put() on the returned device.
1036  *
1037  * See additional information in acpi_dev_present() as well.
1038  */
1039 struct acpi_device *
1040 acpi_dev_get_first_match_dev(const char *hid, const char *uid, s64 hrv)
1041 {
1042 	return acpi_dev_get_next_match_dev(NULL, hid, uid, hrv);
1043 }
1044 EXPORT_SYMBOL(acpi_dev_get_first_match_dev);
1045 
1046 /**
1047  * acpi_reduced_hardware - Return if this is an ACPI-reduced-hw machine
1048  *
1049  * Return true when running on an ACPI-reduced-hw machine, false otherwise.
1050  */
1051 bool acpi_reduced_hardware(void)
1052 {
1053 	return acpi_gbl_reduced_hardware;
1054 }
1055 EXPORT_SYMBOL_GPL(acpi_reduced_hardware);
1056 
1057 /*
1058  * acpi_backlight= handling, this is done here rather then in video_detect.c
1059  * because __setup cannot be used in modules.
1060  */
1061 char acpi_video_backlight_string[16];
1062 EXPORT_SYMBOL(acpi_video_backlight_string);
1063 
1064 static int __init acpi_backlight(char *str)
1065 {
1066 	strscpy(acpi_video_backlight_string, str,
1067 		sizeof(acpi_video_backlight_string));
1068 	return 1;
1069 }
1070 __setup("acpi_backlight=", acpi_backlight);
1071 
1072 /**
1073  * acpi_match_platform_list - Check if the system matches with a given list
1074  * @plat: pointer to acpi_platform_list table terminated by a NULL entry
1075  *
1076  * Return the matched index if the system is found in the platform list.
1077  * Otherwise, return a negative error code.
1078  */
1079 int acpi_match_platform_list(const struct acpi_platform_list *plat)
1080 {
1081 	struct acpi_table_header hdr;
1082 	int idx = 0;
1083 
1084 	if (acpi_disabled)
1085 		return -ENODEV;
1086 
1087 	for (; plat->oem_id[0]; plat++, idx++) {
1088 		if (ACPI_FAILURE(acpi_get_table_header(plat->table, 0, &hdr)))
1089 			continue;
1090 
1091 		if (strncmp(plat->oem_id, hdr.oem_id, ACPI_OEM_ID_SIZE))
1092 			continue;
1093 
1094 		if (strncmp(plat->oem_table_id, hdr.oem_table_id, ACPI_OEM_TABLE_ID_SIZE))
1095 			continue;
1096 
1097 		if ((plat->pred == all_versions) ||
1098 		    (plat->pred == less_than_or_equal && hdr.oem_revision <= plat->oem_revision) ||
1099 		    (plat->pred == greater_than_or_equal && hdr.oem_revision >= plat->oem_revision) ||
1100 		    (plat->pred == equal && hdr.oem_revision == plat->oem_revision))
1101 			return idx;
1102 	}
1103 
1104 	return -ENODEV;
1105 }
1106 EXPORT_SYMBOL(acpi_match_platform_list);
1107