xref: /linux/drivers/acpi/utils.c (revision aaa44952bbd1d4db14a4d676bf9595bb5db7e7b0)
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 acpi_status
281 acpi_evaluate_reference(acpi_handle handle,
282 			acpi_string pathname,
283 			struct acpi_object_list *arguments,
284 			struct acpi_handle_list *list)
285 {
286 	acpi_status status = AE_OK;
287 	union acpi_object *package = NULL;
288 	union acpi_object *element = NULL;
289 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
290 	u32 i = 0;
291 
292 
293 	if (!list) {
294 		return AE_BAD_PARAMETER;
295 	}
296 
297 	/* Evaluate object. */
298 
299 	status = acpi_evaluate_object(handle, pathname, arguments, &buffer);
300 	if (ACPI_FAILURE(status))
301 		goto end;
302 
303 	package = buffer.pointer;
304 
305 	if ((buffer.length == 0) || !package) {
306 		status = AE_BAD_DATA;
307 		acpi_util_eval_error(handle, pathname, status);
308 		goto end;
309 	}
310 	if (package->type != ACPI_TYPE_PACKAGE) {
311 		status = AE_BAD_DATA;
312 		acpi_util_eval_error(handle, pathname, status);
313 		goto end;
314 	}
315 	if (!package->package.count) {
316 		status = AE_BAD_DATA;
317 		acpi_util_eval_error(handle, pathname, status);
318 		goto end;
319 	}
320 
321 	if (package->package.count > ACPI_MAX_HANDLES) {
322 		kfree(package);
323 		return AE_NO_MEMORY;
324 	}
325 	list->count = package->package.count;
326 
327 	/* Extract package data. */
328 
329 	for (i = 0; i < list->count; i++) {
330 
331 		element = &(package->package.elements[i]);
332 
333 		if (element->type != ACPI_TYPE_LOCAL_REFERENCE) {
334 			status = AE_BAD_DATA;
335 			acpi_util_eval_error(handle, pathname, status);
336 			break;
337 		}
338 
339 		if (!element->reference.handle) {
340 			status = AE_NULL_ENTRY;
341 			acpi_util_eval_error(handle, pathname, status);
342 			break;
343 		}
344 		/* Get the  acpi_handle. */
345 
346 		list->handles[i] = element->reference.handle;
347 		acpi_handle_debug(list->handles[i], "Found in reference list\n");
348 	}
349 
350       end:
351 	if (ACPI_FAILURE(status)) {
352 		list->count = 0;
353 		//kfree(list->handles);
354 	}
355 
356 	kfree(buffer.pointer);
357 
358 	return status;
359 }
360 
361 EXPORT_SYMBOL(acpi_evaluate_reference);
362 
363 acpi_status
364 acpi_get_physical_device_location(acpi_handle handle, struct acpi_pld_info **pld)
365 {
366 	acpi_status status;
367 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
368 	union acpi_object *output;
369 
370 	status = acpi_evaluate_object(handle, "_PLD", NULL, &buffer);
371 
372 	if (ACPI_FAILURE(status))
373 		return status;
374 
375 	output = buffer.pointer;
376 
377 	if (!output || output->type != ACPI_TYPE_PACKAGE
378 	    || !output->package.count
379 	    || output->package.elements[0].type != ACPI_TYPE_BUFFER
380 	    || output->package.elements[0].buffer.length < ACPI_PLD_REV1_BUFFER_SIZE) {
381 		status = AE_TYPE;
382 		goto out;
383 	}
384 
385 	status = acpi_decode_pld_buffer(
386 			output->package.elements[0].buffer.pointer,
387 			output->package.elements[0].buffer.length,
388 			pld);
389 
390 out:
391 	kfree(buffer.pointer);
392 	return status;
393 }
394 EXPORT_SYMBOL(acpi_get_physical_device_location);
395 
396 /**
397  * acpi_evaluate_ost: Evaluate _OST for hotplug operations
398  * @handle: ACPI device handle
399  * @source_event: source event code
400  * @status_code: status code
401  * @status_buf: optional detailed information (NULL if none)
402  *
403  * Evaluate _OST for hotplug operations. All ACPI hotplug handlers
404  * must call this function when evaluating _OST for hotplug operations.
405  * When the platform does not support _OST, this function has no effect.
406  */
407 acpi_status
408 acpi_evaluate_ost(acpi_handle handle, u32 source_event, u32 status_code,
409 		  struct acpi_buffer *status_buf)
410 {
411 	union acpi_object params[3] = {
412 		{.type = ACPI_TYPE_INTEGER,},
413 		{.type = ACPI_TYPE_INTEGER,},
414 		{.type = ACPI_TYPE_BUFFER,}
415 	};
416 	struct acpi_object_list arg_list = {3, params};
417 
418 	params[0].integer.value = source_event;
419 	params[1].integer.value = status_code;
420 	if (status_buf != NULL) {
421 		params[2].buffer.pointer = status_buf->pointer;
422 		params[2].buffer.length = status_buf->length;
423 	} else {
424 		params[2].buffer.pointer = NULL;
425 		params[2].buffer.length = 0;
426 	}
427 
428 	return acpi_evaluate_object(handle, "_OST", &arg_list, NULL);
429 }
430 EXPORT_SYMBOL(acpi_evaluate_ost);
431 
432 /**
433  * acpi_handle_path: Return the object path of handle
434  * @handle: ACPI device handle
435  *
436  * Caller must free the returned buffer
437  */
438 static char *acpi_handle_path(acpi_handle handle)
439 {
440 	struct acpi_buffer buffer = {
441 		.length = ACPI_ALLOCATE_BUFFER,
442 		.pointer = NULL
443 	};
444 
445 	if (in_interrupt() ||
446 	    acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer) != AE_OK)
447 		return NULL;
448 	return buffer.pointer;
449 }
450 
451 /**
452  * acpi_handle_printk: Print message with ACPI prefix and object path
453  * @level: log level
454  * @handle: ACPI device handle
455  * @fmt: format string
456  *
457  * This function is called through acpi_handle_<level> macros and prints
458  * a message with ACPI prefix and object path.  This function acquires
459  * the global namespace mutex to obtain an object path.  In interrupt
460  * context, it shows the object path as <n/a>.
461  */
462 void
463 acpi_handle_printk(const char *level, acpi_handle handle, const char *fmt, ...)
464 {
465 	struct va_format vaf;
466 	va_list args;
467 	const char *path;
468 
469 	va_start(args, fmt);
470 	vaf.fmt = fmt;
471 	vaf.va = &args;
472 
473 	path = acpi_handle_path(handle);
474 	printk("%sACPI: %s: %pV", level, path ? path : "<n/a>" , &vaf);
475 
476 	va_end(args);
477 	kfree(path);
478 }
479 EXPORT_SYMBOL(acpi_handle_printk);
480 
481 #if defined(CONFIG_DYNAMIC_DEBUG)
482 /**
483  * __acpi_handle_debug: pr_debug with ACPI prefix and object path
484  * @descriptor: Dynamic Debug descriptor
485  * @handle: ACPI device handle
486  * @fmt: format string
487  *
488  * This function is called through acpi_handle_debug macro and debug
489  * prints a message with ACPI prefix and object path. This function
490  * acquires the global namespace mutex to obtain an object path.  In
491  * interrupt context, it shows the object path as <n/a>.
492  */
493 void
494 __acpi_handle_debug(struct _ddebug *descriptor, acpi_handle handle,
495 		    const char *fmt, ...)
496 {
497 	struct va_format vaf;
498 	va_list args;
499 	const char *path;
500 
501 	va_start(args, fmt);
502 	vaf.fmt = fmt;
503 	vaf.va = &args;
504 
505 	path = acpi_handle_path(handle);
506 	__dynamic_pr_debug(descriptor, "ACPI: %s: %pV", path ? path : "<n/a>", &vaf);
507 
508 	va_end(args);
509 	kfree(path);
510 }
511 EXPORT_SYMBOL(__acpi_handle_debug);
512 #endif
513 
514 /**
515  * acpi_evaluation_failure_warn - Log evaluation failure warning.
516  * @handle: Parent object handle.
517  * @name: Name of the object whose evaluation has failed.
518  * @status: Status value returned by the failing object evaluation.
519  */
520 void acpi_evaluation_failure_warn(acpi_handle handle, const char *name,
521 				  acpi_status status)
522 {
523 	acpi_handle_warn(handle, "%s evaluation failed: %s\n", name,
524 			 acpi_format_exception(status));
525 }
526 EXPORT_SYMBOL_GPL(acpi_evaluation_failure_warn);
527 
528 /**
529  * acpi_has_method: Check whether @handle has a method named @name
530  * @handle: ACPI device handle
531  * @name: name of object or method
532  *
533  * Check whether @handle has a method named @name.
534  */
535 bool acpi_has_method(acpi_handle handle, char *name)
536 {
537 	acpi_handle tmp;
538 
539 	return ACPI_SUCCESS(acpi_get_handle(handle, name, &tmp));
540 }
541 EXPORT_SYMBOL(acpi_has_method);
542 
543 acpi_status acpi_execute_simple_method(acpi_handle handle, char *method,
544 				       u64 arg)
545 {
546 	union acpi_object obj = { .type = ACPI_TYPE_INTEGER };
547 	struct acpi_object_list arg_list = { .count = 1, .pointer = &obj, };
548 
549 	obj.integer.value = arg;
550 
551 	return acpi_evaluate_object(handle, method, &arg_list, NULL);
552 }
553 EXPORT_SYMBOL(acpi_execute_simple_method);
554 
555 /**
556  * acpi_evaluate_ej0: Evaluate _EJ0 method for hotplug operations
557  * @handle: ACPI device handle
558  *
559  * Evaluate device's _EJ0 method for hotplug operations.
560  */
561 acpi_status acpi_evaluate_ej0(acpi_handle handle)
562 {
563 	acpi_status status;
564 
565 	status = acpi_execute_simple_method(handle, "_EJ0", 1);
566 	if (status == AE_NOT_FOUND)
567 		acpi_handle_warn(handle, "No _EJ0 support for device\n");
568 	else if (ACPI_FAILURE(status))
569 		acpi_handle_warn(handle, "Eject failed (0x%x)\n", status);
570 
571 	return status;
572 }
573 
574 /**
575  * acpi_evaluate_lck: Evaluate _LCK method to lock/unlock device
576  * @handle: ACPI device handle
577  * @lock: lock device if non-zero, otherwise unlock device
578  *
579  * Evaluate device's _LCK method if present to lock/unlock device
580  */
581 acpi_status acpi_evaluate_lck(acpi_handle handle, int lock)
582 {
583 	acpi_status status;
584 
585 	status = acpi_execute_simple_method(handle, "_LCK", !!lock);
586 	if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {
587 		if (lock)
588 			acpi_handle_warn(handle,
589 				"Locking device failed (0x%x)\n", status);
590 		else
591 			acpi_handle_warn(handle,
592 				"Unlocking device failed (0x%x)\n", status);
593 	}
594 
595 	return status;
596 }
597 
598 /**
599  * acpi_evaluate_reg: Evaluate _REG method to register OpRegion presence
600  * @handle: ACPI device handle
601  * @space_id: ACPI address space id to register OpRegion presence for
602  * @function: Parameter to pass to _REG one of ACPI_REG_CONNECT or
603  *            ACPI_REG_DISCONNECT
604  *
605  * Evaluate device's _REG method to register OpRegion presence.
606  */
607 acpi_status acpi_evaluate_reg(acpi_handle handle, u8 space_id, u32 function)
608 {
609 	struct acpi_object_list arg_list;
610 	union acpi_object params[2];
611 
612 	params[0].type = ACPI_TYPE_INTEGER;
613 	params[0].integer.value = space_id;
614 	params[1].type = ACPI_TYPE_INTEGER;
615 	params[1].integer.value = function;
616 	arg_list.count = 2;
617 	arg_list.pointer = params;
618 
619 	return acpi_evaluate_object(handle, "_REG", &arg_list, NULL);
620 }
621 EXPORT_SYMBOL(acpi_evaluate_reg);
622 
623 /**
624  * acpi_evaluate_dsm - evaluate device's _DSM method
625  * @handle: ACPI device handle
626  * @guid: GUID of requested functions, should be 16 bytes
627  * @rev: revision number of requested function
628  * @func: requested function number
629  * @argv4: the function specific parameter
630  *
631  * Evaluate device's _DSM method with specified GUID, revision id and
632  * function number. Caller needs to free the returned object.
633  *
634  * Though ACPI defines the fourth parameter for _DSM should be a package,
635  * some old BIOSes do expect a buffer or an integer etc.
636  */
637 union acpi_object *
638 acpi_evaluate_dsm(acpi_handle handle, const guid_t *guid, u64 rev, u64 func,
639 		  union acpi_object *argv4)
640 {
641 	acpi_status ret;
642 	struct acpi_buffer buf = {ACPI_ALLOCATE_BUFFER, NULL};
643 	union acpi_object params[4];
644 	struct acpi_object_list input = {
645 		.count = 4,
646 		.pointer = params,
647 	};
648 
649 	params[0].type = ACPI_TYPE_BUFFER;
650 	params[0].buffer.length = 16;
651 	params[0].buffer.pointer = (u8 *)guid;
652 	params[1].type = ACPI_TYPE_INTEGER;
653 	params[1].integer.value = rev;
654 	params[2].type = ACPI_TYPE_INTEGER;
655 	params[2].integer.value = func;
656 	if (argv4) {
657 		params[3] = *argv4;
658 	} else {
659 		params[3].type = ACPI_TYPE_PACKAGE;
660 		params[3].package.count = 0;
661 		params[3].package.elements = NULL;
662 	}
663 
664 	ret = acpi_evaluate_object(handle, "_DSM", &input, &buf);
665 	if (ACPI_SUCCESS(ret))
666 		return (union acpi_object *)buf.pointer;
667 
668 	if (ret != AE_NOT_FOUND)
669 		acpi_handle_warn(handle,
670 				"failed to evaluate _DSM (0x%x)\n", ret);
671 
672 	return NULL;
673 }
674 EXPORT_SYMBOL(acpi_evaluate_dsm);
675 
676 /**
677  * acpi_check_dsm - check if _DSM method supports requested functions.
678  * @handle: ACPI device handle
679  * @guid: GUID of requested functions, should be 16 bytes at least
680  * @rev: revision number of requested functions
681  * @funcs: bitmap of requested functions
682  *
683  * Evaluate device's _DSM method to check whether it supports requested
684  * functions. Currently only support 64 functions at maximum, should be
685  * enough for now.
686  */
687 bool acpi_check_dsm(acpi_handle handle, const guid_t *guid, u64 rev, u64 funcs)
688 {
689 	int i;
690 	u64 mask = 0;
691 	union acpi_object *obj;
692 
693 	if (funcs == 0)
694 		return false;
695 
696 	obj = acpi_evaluate_dsm(handle, guid, rev, 0, NULL);
697 	if (!obj)
698 		return false;
699 
700 	/* For compatibility, old BIOSes may return an integer */
701 	if (obj->type == ACPI_TYPE_INTEGER)
702 		mask = obj->integer.value;
703 	else if (obj->type == ACPI_TYPE_BUFFER)
704 		for (i = 0; i < obj->buffer.length && i < 8; i++)
705 			mask |= (((u64)obj->buffer.pointer[i]) << (i * 8));
706 	ACPI_FREE(obj);
707 
708 	/*
709 	 * Bit 0 indicates whether there's support for any functions other than
710 	 * function 0 for the specified GUID and revision.
711 	 */
712 	if ((mask & 0x1) && (mask & funcs) == funcs)
713 		return true;
714 
715 	return false;
716 }
717 EXPORT_SYMBOL(acpi_check_dsm);
718 
719 /**
720  * acpi_dev_hid_uid_match - Match device by supplied HID and UID
721  * @adev: ACPI device to match.
722  * @hid2: Hardware ID of the device.
723  * @uid2: Unique ID of the device, pass NULL to not check _UID.
724  *
725  * Matches HID and UID in @adev with given @hid2 and @uid2.
726  * Returns true if matches.
727  */
728 bool acpi_dev_hid_uid_match(struct acpi_device *adev,
729 			    const char *hid2, const char *uid2)
730 {
731 	const char *hid1 = acpi_device_hid(adev);
732 	const char *uid1 = acpi_device_uid(adev);
733 
734 	if (strcmp(hid1, hid2))
735 		return false;
736 
737 	if (!uid2)
738 		return true;
739 
740 	return uid1 && !strcmp(uid1, uid2);
741 }
742 EXPORT_SYMBOL(acpi_dev_hid_uid_match);
743 
744 /**
745  * acpi_dev_found - Detect presence of a given ACPI device in the namespace.
746  * @hid: Hardware ID of the device.
747  *
748  * Return %true if the device was present at the moment of invocation.
749  * Note that if the device is pluggable, it may since have disappeared.
750  *
751  * For this function to work, acpi_bus_scan() must have been executed
752  * which happens in the subsys_initcall() subsection. Hence, do not
753  * call from a subsys_initcall() or earlier (use acpi_get_devices()
754  * instead). Calling from module_init() is fine (which is synonymous
755  * with device_initcall()).
756  */
757 bool acpi_dev_found(const char *hid)
758 {
759 	struct acpi_device_bus_id *acpi_device_bus_id;
760 	bool found = false;
761 
762 	mutex_lock(&acpi_device_lock);
763 	list_for_each_entry(acpi_device_bus_id, &acpi_bus_id_list, node)
764 		if (!strcmp(acpi_device_bus_id->bus_id, hid)) {
765 			found = true;
766 			break;
767 		}
768 	mutex_unlock(&acpi_device_lock);
769 
770 	return found;
771 }
772 EXPORT_SYMBOL(acpi_dev_found);
773 
774 struct acpi_dev_match_info {
775 	struct acpi_device_id hid[2];
776 	const char *uid;
777 	s64 hrv;
778 };
779 
780 static int acpi_dev_match_cb(struct device *dev, const void *data)
781 {
782 	struct acpi_device *adev = to_acpi_device(dev);
783 	const struct acpi_dev_match_info *match = data;
784 	unsigned long long hrv;
785 	acpi_status status;
786 
787 	if (acpi_match_device_ids(adev, match->hid))
788 		return 0;
789 
790 	if (match->uid && (!adev->pnp.unique_id ||
791 	    strcmp(adev->pnp.unique_id, match->uid)))
792 		return 0;
793 
794 	if (match->hrv == -1)
795 		return 1;
796 
797 	status = acpi_evaluate_integer(adev->handle, "_HRV", NULL, &hrv);
798 	if (ACPI_FAILURE(status))
799 		return 0;
800 
801 	return hrv == match->hrv;
802 }
803 
804 /**
805  * acpi_dev_present - Detect that a given ACPI device is present
806  * @hid: Hardware ID of the device.
807  * @uid: Unique ID of the device, pass NULL to not check _UID
808  * @hrv: Hardware Revision of the device, pass -1 to not check _HRV
809  *
810  * Return %true if a matching device was present at the moment of invocation.
811  * Note that if the device is pluggable, it may since have disappeared.
812  *
813  * Note that unlike acpi_dev_found() this function checks the status
814  * of the device. So for devices which are present in the DSDT, but
815  * which are disabled (their _STA callback returns 0) this function
816  * will return false.
817  *
818  * For this function to work, acpi_bus_scan() must have been executed
819  * which happens in the subsys_initcall() subsection. Hence, do not
820  * call from a subsys_initcall() or earlier (use acpi_get_devices()
821  * instead). Calling from module_init() is fine (which is synonymous
822  * with device_initcall()).
823  */
824 bool acpi_dev_present(const char *hid, const char *uid, s64 hrv)
825 {
826 	struct acpi_dev_match_info match = {};
827 	struct device *dev;
828 
829 	strlcpy(match.hid[0].id, hid, sizeof(match.hid[0].id));
830 	match.uid = uid;
831 	match.hrv = hrv;
832 
833 	dev = bus_find_device(&acpi_bus_type, NULL, &match, acpi_dev_match_cb);
834 	put_device(dev);
835 	return !!dev;
836 }
837 EXPORT_SYMBOL(acpi_dev_present);
838 
839 /**
840  * acpi_dev_get_next_match_dev - Return the next match of ACPI device
841  * @adev: Pointer to the previous ACPI device matching this @hid, @uid and @hrv
842  * @hid: Hardware ID of the device.
843  * @uid: Unique ID of the device, pass NULL to not check _UID
844  * @hrv: Hardware Revision of the device, pass -1 to not check _HRV
845  *
846  * Return the next match of ACPI device if another matching device was present
847  * at the moment of invocation, or NULL otherwise.
848  *
849  * FIXME: The function does not tolerate the sudden disappearance of @adev, e.g.
850  * in the case of a hotplug event. That said, the caller should ensure that
851  * this will never happen.
852  *
853  * The caller is responsible for invoking acpi_dev_put() on the returned device.
854  *
855  * See additional information in acpi_dev_present() as well.
856  */
857 struct acpi_device *
858 acpi_dev_get_next_match_dev(struct acpi_device *adev, const char *hid, const char *uid, s64 hrv)
859 {
860 	struct device *start = adev ? &adev->dev : NULL;
861 	struct acpi_dev_match_info match = {};
862 	struct device *dev;
863 
864 	strlcpy(match.hid[0].id, hid, sizeof(match.hid[0].id));
865 	match.uid = uid;
866 	match.hrv = hrv;
867 
868 	dev = bus_find_device(&acpi_bus_type, start, &match, acpi_dev_match_cb);
869 	return dev ? to_acpi_device(dev) : NULL;
870 }
871 EXPORT_SYMBOL(acpi_dev_get_next_match_dev);
872 
873 /**
874  * acpi_dev_get_first_match_dev - Return the first match of ACPI device
875  * @hid: Hardware ID of the device.
876  * @uid: Unique ID of the device, pass NULL to not check _UID
877  * @hrv: Hardware Revision of the device, pass -1 to not check _HRV
878  *
879  * Return the first match of ACPI device if a matching device was present
880  * at the moment of invocation, or NULL otherwise.
881  *
882  * The caller is responsible for invoking acpi_dev_put() on the returned device.
883  *
884  * See additional information in acpi_dev_present() as well.
885  */
886 struct acpi_device *
887 acpi_dev_get_first_match_dev(const char *hid, const char *uid, s64 hrv)
888 {
889 	return acpi_dev_get_next_match_dev(NULL, hid, uid, hrv);
890 }
891 EXPORT_SYMBOL(acpi_dev_get_first_match_dev);
892 
893 /**
894  * acpi_reduced_hardware - Return if this is an ACPI-reduced-hw machine
895  *
896  * Return true when running on an ACPI-reduced-hw machine, false otherwise.
897  */
898 bool acpi_reduced_hardware(void)
899 {
900 	return acpi_gbl_reduced_hardware;
901 }
902 EXPORT_SYMBOL_GPL(acpi_reduced_hardware);
903 
904 /*
905  * acpi_backlight= handling, this is done here rather then in video_detect.c
906  * because __setup cannot be used in modules.
907  */
908 char acpi_video_backlight_string[16];
909 EXPORT_SYMBOL(acpi_video_backlight_string);
910 
911 static int __init acpi_backlight(char *str)
912 {
913 	strlcpy(acpi_video_backlight_string, str,
914 		sizeof(acpi_video_backlight_string));
915 	return 1;
916 }
917 __setup("acpi_backlight=", acpi_backlight);
918 
919 /**
920  * acpi_match_platform_list - Check if the system matches with a given list
921  * @plat: pointer to acpi_platform_list table terminated by a NULL entry
922  *
923  * Return the matched index if the system is found in the platform list.
924  * Otherwise, return a negative error code.
925  */
926 int acpi_match_platform_list(const struct acpi_platform_list *plat)
927 {
928 	struct acpi_table_header hdr;
929 	int idx = 0;
930 
931 	if (acpi_disabled)
932 		return -ENODEV;
933 
934 	for (; plat->oem_id[0]; plat++, idx++) {
935 		if (ACPI_FAILURE(acpi_get_table_header(plat->table, 0, &hdr)))
936 			continue;
937 
938 		if (strncmp(plat->oem_id, hdr.oem_id, ACPI_OEM_ID_SIZE))
939 			continue;
940 
941 		if (strncmp(plat->oem_table_id, hdr.oem_table_id, ACPI_OEM_TABLE_ID_SIZE))
942 			continue;
943 
944 		if ((plat->pred == all_versions) ||
945 		    (plat->pred == less_than_or_equal && hdr.oem_revision <= plat->oem_revision) ||
946 		    (plat->pred == greater_than_or_equal && hdr.oem_revision >= plat->oem_revision) ||
947 		    (plat->pred == equal && hdr.oem_revision == plat->oem_revision))
948 			return idx;
949 	}
950 
951 	return -ENODEV;
952 }
953 EXPORT_SYMBOL(acpi_match_platform_list);
954