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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#include <linux/kernel.h>
10#include <linux/module.h>
11#include <linux/slab.h>
12#include <linux/init.h>
13#include <linux/types.h>
14#include <linux/hardirq.h>
15#include <linux/acpi.h>
16#include <linux/dynamic_debug.h>
17
18#include "internal.h"
19#include "sleep.h"
20
21#define _COMPONENT ACPI_BUS_COMPONENT
22ACPI_MODULE_NAME("utils");
23
24/* --------------------------------------------------------------------------
25 Object Evaluation Helpers
26 -------------------------------------------------------------------------- */
27static void
28acpi_util_eval_error(acpi_handle h, acpi_string p, acpi_status s)
29{
30#ifdef ACPI_DEBUG_OUTPUT
31 char prefix[80] = {'\0'};
32 struct acpi_buffer buffer = {sizeof(prefix), prefix};
33 acpi_get_name(h, ACPI_FULL_PATHNAME, &buffer);
34 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Evaluate [%s.%s]: %s\n",
35 (char *) prefix, p, acpi_format_exception(s)));
36#else
37 return;
38#endif
39}
40
41acpi_status
42acpi_extract_package(union acpi_object *package,
43 struct acpi_buffer *format, struct acpi_buffer *buffer)
44{
45 u32 size_required = 0;
46 u32 tail_offset = 0;
47 char *format_string = NULL;
48 u32 format_count = 0;
49 u32 i = 0;
50 u8 *head = NULL;
51 u8 *tail = NULL;
52
53
54 if (!package || (package->type != ACPI_TYPE_PACKAGE)
55 || (package->package.count < 1)) {
56 printk(KERN_WARNING PREFIX "Invalid package argument\n");
57 return AE_BAD_PARAMETER;
58 }
59
60 if (!format || !format->pointer || (format->length < 1)) {
61 printk(KERN_WARNING PREFIX "Invalid format argument\n");
62 return AE_BAD_PARAMETER;
63 }
64
65 if (!buffer) {
66 printk(KERN_WARNING PREFIX "Invalid buffer argument\n");
67 return AE_BAD_PARAMETER;
68 }
69
70 format_count = (format->length / sizeof(char)) - 1;
71 if (format_count > package->package.count) {
72 printk(KERN_WARNING PREFIX "Format specifies more objects [%d]"
73 " than exist in package [%d].\n",
74 format_count, package->package.count);
75 return AE_BAD_DATA;
76 }
77
78 format_string = format->pointer;
79
80 /*
81 * Calculate size_required.
82 */
83 for (i = 0; i < format_count; i++) {
84
85 union acpi_object *element = &(package->package.elements[i]);
86
87 switch (element->type) {
88
89 case ACPI_TYPE_INTEGER:
90 switch (format_string[i]) {
91 case 'N':
92 size_required += sizeof(u64);
93 tail_offset += sizeof(u64);
94 break;
95 case 'S':
96 size_required +=
97 sizeof(char *) + sizeof(u64) +
98 sizeof(char);
99 tail_offset += sizeof(char *);
100 break;
101 default:
102 printk(KERN_WARNING PREFIX "Invalid package element"
103 " [%d]: got number, expecting"
104 " [%c]\n",
105 i, format_string[i]);
106 return AE_BAD_DATA;
107 break;
108 }
109 break;
110
111 case ACPI_TYPE_STRING:
112 case ACPI_TYPE_BUFFER:
113 switch (format_string[i]) {
114 case 'S':
115 size_required +=
116 sizeof(char *) +
117 (element->string.length * sizeof(char)) +
118 sizeof(char);
119 tail_offset += sizeof(char *);
120 break;
121 case 'B':
122 size_required +=
123 sizeof(u8 *) + element->buffer.length;
124 tail_offset += sizeof(u8 *);
125 break;
126 default:
127 printk(KERN_WARNING PREFIX "Invalid package element"
128 " [%d] got string/buffer,"
129 " expecting [%c]\n",
130 i, format_string[i]);
131 return AE_BAD_DATA;
132 break;
133 }
134 break;
135 case ACPI_TYPE_LOCAL_REFERENCE:
136 switch (format_string[i]) {
137 case 'R':
138 size_required += sizeof(void *);
139 tail_offset += sizeof(void *);
140 break;
141 default:
142 printk(KERN_WARNING PREFIX "Invalid package element"
143 " [%d] got reference,"
144 " expecting [%c]\n",
145 i, format_string[i]);
146 return AE_BAD_DATA;
147 break;
148 }
149 break;
150
151 case ACPI_TYPE_PACKAGE:
152 default:
153 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
154 "Found unsupported element at index=%d\n",
155 i));
156 /* TBD: handle nested packages... */
157 return AE_SUPPORT;
158 break;
159 }
160 }
161
162 /*
163 * Validate output buffer.
164 */
165 if (buffer->length == ACPI_ALLOCATE_BUFFER) {
166 buffer->pointer = ACPI_ALLOCATE_ZEROED(size_required);
167 if (!buffer->pointer)
168 return AE_NO_MEMORY;
169 buffer->length = size_required;
170 } else {
171 if (buffer->length < size_required) {
172 buffer->length = size_required;
173 return AE_BUFFER_OVERFLOW;
174 } else if (buffer->length != size_required ||
175 !buffer->pointer) {
176 return AE_BAD_PARAMETER;
177 }
178 }
179
180 head = buffer->pointer;
181 tail = buffer->pointer + tail_offset;
182
183 /*
184 * Extract package data.
185 */
186 for (i = 0; i < format_count; i++) {
187
188 u8 **pointer = NULL;
189 union acpi_object *element = &(package->package.elements[i]);
190
191 switch (element->type) {
192
193 case ACPI_TYPE_INTEGER:
194 switch (format_string[i]) {
195 case 'N':
196 *((u64 *) head) =
197 element->integer.value;
198 head += sizeof(u64);
199 break;
200 case 'S':
201 pointer = (u8 **) head;
202 *pointer = tail;
203 *((u64 *) tail) =
204 element->integer.value;
205 head += sizeof(u64 *);
206 tail += sizeof(u64);
207 /* NULL terminate string */
208 *tail = (char)0;
209 tail += sizeof(char);
210 break;
211 default:
212 /* Should never get here */
213 break;
214 }
215 break;
216
217 case ACPI_TYPE_STRING:
218 case ACPI_TYPE_BUFFER:
219 switch (format_string[i]) {
220 case 'S':
221 pointer = (u8 **) head;
222 *pointer = tail;
223 memcpy(tail, element->string.pointer,
224 element->string.length);
225 head += sizeof(char *);
226 tail += element->string.length * sizeof(char);
227 /* NULL terminate string */
228 *tail = (char)0;
229 tail += sizeof(char);
230 break;
231 case 'B':
232 pointer = (u8 **) head;
233 *pointer = tail;
234 memcpy(tail, element->buffer.pointer,
235 element->buffer.length);
236 head += sizeof(u8 *);
237 tail += element->buffer.length;
238 break;
239 default:
240 /* Should never get here */
241 break;
242 }
243 break;
244 case ACPI_TYPE_LOCAL_REFERENCE:
245 switch (format_string[i]) {
246 case 'R':
247 *(void **)head =
248 (void *)element->reference.handle;
249 head += sizeof(void *);
250 break;
251 default:
252 /* Should never get here */
253 break;
254 }
255 break;
256 case ACPI_TYPE_PACKAGE:
257 /* TBD: handle nested packages... */
258 default:
259 /* Should never get here */
260 break;
261 }
262 }
263
264 return AE_OK;
265}
266
267EXPORT_SYMBOL(acpi_extract_package);
268
269acpi_status
270acpi_evaluate_integer(acpi_handle handle,
271 acpi_string pathname,
272 struct acpi_object_list *arguments, unsigned long long *data)
273{
274 acpi_status status = AE_OK;
275 union acpi_object element;
276 struct acpi_buffer buffer = { 0, NULL };
277
278 if (!data)
279 return AE_BAD_PARAMETER;
280
281 buffer.length = sizeof(union acpi_object);
282 buffer.pointer = &element;
283 status = acpi_evaluate_object(handle, pathname, arguments, &buffer);
284 if (ACPI_FAILURE(status)) {
285 acpi_util_eval_error(handle, pathname, status);
286 return status;
287 }
288
289 if (element.type != ACPI_TYPE_INTEGER) {
290 acpi_util_eval_error(handle, pathname, AE_BAD_DATA);
291 return AE_BAD_DATA;
292 }
293
294 *data = element.integer.value;
295
296 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Return value [%llu]\n", *data));
297
298 return AE_OK;
299}
300
301EXPORT_SYMBOL(acpi_evaluate_integer);
302
303acpi_status
304acpi_evaluate_reference(acpi_handle handle,
305 acpi_string pathname,
306 struct acpi_object_list *arguments,
307 struct acpi_handle_list *list)
308{
309 acpi_status status = AE_OK;
310 union acpi_object *package = NULL;
311 union acpi_object *element = NULL;
312 struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
313 u32 i = 0;
314
315
316 if (!list) {
317 return AE_BAD_PARAMETER;
318 }
319
320 /* Evaluate object. */
321
322 status = acpi_evaluate_object(handle, pathname, arguments, &buffer);
323 if (ACPI_FAILURE(status))
324 goto end;
325
326 package = buffer.pointer;
327
328 if ((buffer.length == 0) || !package) {
329 status = AE_BAD_DATA;
330 acpi_util_eval_error(handle, pathname, status);
331 goto end;
332 }
333 if (package->type != ACPI_TYPE_PACKAGE) {
334 status = AE_BAD_DATA;
335 acpi_util_eval_error(handle, pathname, status);
336 goto end;
337 }
338 if (!package->package.count) {
339 status = AE_BAD_DATA;
340 acpi_util_eval_error(handle, pathname, status);
341 goto end;
342 }
343
344 if (package->package.count > ACPI_MAX_HANDLES) {
345 kfree(package);
346 return AE_NO_MEMORY;
347 }
348 list->count = package->package.count;
349
350 /* Extract package data. */
351
352 for (i = 0; i < list->count; i++) {
353
354 element = &(package->package.elements[i]);
355
356 if (element->type != ACPI_TYPE_LOCAL_REFERENCE) {
357 status = AE_BAD_DATA;
358 acpi_util_eval_error(handle, pathname, status);
359 break;
360 }
361
362 if (!element->reference.handle) {
363 status = AE_NULL_ENTRY;
364 acpi_util_eval_error(handle, pathname, status);
365 break;
366 }
367 /* Get the acpi_handle. */
368
369 list->handles[i] = element->reference.handle;
370 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found reference [%p]\n",
371 list->handles[i]));
372 }
373
374 end:
375 if (ACPI_FAILURE(status)) {
376 list->count = 0;
377 //kfree(list->handles);
378 }
379
380 kfree(buffer.pointer);
381
382 return status;
383}
384
385EXPORT_SYMBOL(acpi_evaluate_reference);
386
387acpi_status
388acpi_get_physical_device_location(acpi_handle handle, struct acpi_pld_info **pld)
389{
390 acpi_status status;
391 struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
392 union acpi_object *output;
393
394 status = acpi_evaluate_object(handle, "_PLD", NULL, &buffer);
395
396 if (ACPI_FAILURE(status))
397 return status;
398
399 output = buffer.pointer;
400
401 if (!output || output->type != ACPI_TYPE_PACKAGE
402 || !output->package.count
403 || output->package.elements[0].type != ACPI_TYPE_BUFFER
404 || output->package.elements[0].buffer.length < ACPI_PLD_REV1_BUFFER_SIZE) {
405 status = AE_TYPE;
406 goto out;
407 }
408
409 status = acpi_decode_pld_buffer(
410 output->package.elements[0].buffer.pointer,
411 output->package.elements[0].buffer.length,
412 pld);
413
414out:
415 kfree(buffer.pointer);
416 return status;
417}
418EXPORT_SYMBOL(acpi_get_physical_device_location);
419
420/**
421 * acpi_evaluate_ost: Evaluate _OST for hotplug operations
422 * @handle: ACPI device handle
423 * @source_event: source event code
424 * @status_code: status code
425 * @status_buf: optional detailed information (NULL if none)
426 *
427 * Evaluate _OST for hotplug operations. All ACPI hotplug handlers
428 * must call this function when evaluating _OST for hotplug operations.
429 * When the platform does not support _OST, this function has no effect.
430 */
431acpi_status
432acpi_evaluate_ost(acpi_handle handle, u32 source_event, u32 status_code,
433 struct acpi_buffer *status_buf)
434{
435 union acpi_object params[3] = {
436 {.type = ACPI_TYPE_INTEGER,},
437 {.type = ACPI_TYPE_INTEGER,},
438 {.type = ACPI_TYPE_BUFFER,}
439 };
440 struct acpi_object_list arg_list = {3, params};
441
442 params[0].integer.value = source_event;
443 params[1].integer.value = status_code;
444 if (status_buf != NULL) {
445 params[2].buffer.pointer = status_buf->pointer;
446 params[2].buffer.length = status_buf->length;
447 } else {
448 params[2].buffer.pointer = NULL;
449 params[2].buffer.length = 0;
450 }
451
452 return acpi_evaluate_object(handle, "_OST", &arg_list, NULL);
453}
454EXPORT_SYMBOL(acpi_evaluate_ost);
455
456/**
457 * acpi_handle_path: Return the object path of handle
458 *
459 * Caller must free the returned buffer
460 */
461static char *acpi_handle_path(acpi_handle handle)
462{
463 struct acpi_buffer buffer = {
464 .length = ACPI_ALLOCATE_BUFFER,
465 .pointer = NULL
466 };
467
468 if (in_interrupt() ||
469 acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer) != AE_OK)
470 return NULL;
471 return buffer.pointer;
472}
473
474/**
475 * acpi_handle_printk: Print message with ACPI prefix and object path
476 *
477 * This function is called through acpi_handle_<level> macros and prints
478 * a message with ACPI prefix and object path. This function acquires
479 * the global namespace mutex to obtain an object path. In interrupt
480 * context, it shows the object path as <n/a>.
481 */
482void
483acpi_handle_printk(const char *level, acpi_handle handle, const char *fmt, ...)
484{
485 struct va_format vaf;
486 va_list args;
487 const char *path;
488
489 va_start(args, fmt);
490 vaf.fmt = fmt;
491 vaf.va = &args;
492
493 path = acpi_handle_path(handle);
494 printk("%sACPI: %s: %pV", level, path ? path : "<n/a>" , &vaf);
495
496 va_end(args);
497 kfree(path);
498}
499EXPORT_SYMBOL(acpi_handle_printk);
500
501#if defined(CONFIG_DYNAMIC_DEBUG)
502/**
503 * __acpi_handle_debug: pr_debug with ACPI prefix and object path
504 *
505 * This function is called through acpi_handle_debug macro and debug
506 * prints a message with ACPI prefix and object path. This function
507 * acquires the global namespace mutex to obtain an object path. In
508 * interrupt context, it shows the object path as <n/a>.
509 */
510void
511__acpi_handle_debug(struct _ddebug *descriptor, acpi_handle handle,
512 const char *fmt, ...)
513{
514 struct va_format vaf;
515 va_list args;
516 const char *path;
517
518 va_start(args, fmt);
519 vaf.fmt = fmt;
520 vaf.va = &args;
521
522 path = acpi_handle_path(handle);
523 __dynamic_pr_debug(descriptor, "ACPI: %s: %pV", path ? path : "<n/a>", &vaf);
524
525 va_end(args);
526 kfree(path);
527}
528EXPORT_SYMBOL(__acpi_handle_debug);
529#endif
530
531/**
532 * acpi_has_method: Check whether @handle has a method named @name
533 * @handle: ACPI device handle
534 * @name: name of object or method
535 *
536 * Check whether @handle has a method named @name.
537 */
538bool acpi_has_method(acpi_handle handle, char *name)
539{
540 acpi_handle tmp;
541
542 return ACPI_SUCCESS(acpi_get_handle(handle, name, &tmp));
543}
544EXPORT_SYMBOL(acpi_has_method);
545
546acpi_status acpi_execute_simple_method(acpi_handle handle, char *method,
547 u64 arg)
548{
549 union acpi_object obj = { .type = ACPI_TYPE_INTEGER };
550 struct acpi_object_list arg_list = { .count = 1, .pointer = &obj, };
551
552 obj.integer.value = arg;
553
554 return acpi_evaluate_object(handle, method, &arg_list, NULL);
555}
556EXPORT_SYMBOL(acpi_execute_simple_method);
557
558/**
559 * acpi_evaluate_ej0: Evaluate _EJ0 method for hotplug operations
560 * @handle: ACPI device handle
561 *
562 * Evaluate device's _EJ0 method for hotplug operations.
563 */
564acpi_status acpi_evaluate_ej0(acpi_handle handle)
565{
566 acpi_status status;
567
568 status = acpi_execute_simple_method(handle, "_EJ0", 1);
569 if (status == AE_NOT_FOUND)
570 acpi_handle_warn(handle, "No _EJ0 support for device\n");
571 else if (ACPI_FAILURE(status))
572 acpi_handle_warn(handle, "Eject failed (0x%x)\n", status);
573
574 return status;
575}
576
577/**
578 * acpi_evaluate_lck: Evaluate _LCK method to lock/unlock device
579 * @handle: ACPI device handle
580 * @lock: lock device if non-zero, otherwise unlock device
581 *
582 * Evaluate device's _LCK method if present to lock/unlock device
583 */
584acpi_status acpi_evaluate_lck(acpi_handle handle, int lock)
585{
586 acpi_status status;
587
588 status = acpi_execute_simple_method(handle, "_LCK", !!lock);
589 if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {
590 if (lock)
591 acpi_handle_warn(handle,
592 "Locking device failed (0x%x)\n", status);
593 else
594 acpi_handle_warn(handle,
595 "Unlocking device failed (0x%x)\n", status);
596 }
597
598 return status;
599}
600
601/**
602 * acpi_evaluate_dsm - evaluate device's _DSM method
603 * @handle: ACPI device handle
604 * @guid: GUID of requested functions, should be 16 bytes
605 * @rev: revision number of requested function
606 * @func: requested function number
607 * @argv4: the function specific parameter
608 *
609 * Evaluate device's _DSM method with specified GUID, revision id and
610 * function number. Caller needs to free the returned object.
611 *
612 * Though ACPI defines the fourth parameter for _DSM should be a package,
613 * some old BIOSes do expect a buffer or an integer etc.
614 */
615union acpi_object *
616acpi_evaluate_dsm(acpi_handle handle, const guid_t *guid, u64 rev, u64 func,
617 union acpi_object *argv4)
618{
619 acpi_status ret;
620 struct acpi_buffer buf = {ACPI_ALLOCATE_BUFFER, NULL};
621 union acpi_object params[4];
622 struct acpi_object_list input = {
623 .count = 4,
624 .pointer = params,
625 };
626
627 params[0].type = ACPI_TYPE_BUFFER;
628 params[0].buffer.length = 16;
629 params[0].buffer.pointer = (u8 *)guid;
630 params[1].type = ACPI_TYPE_INTEGER;
631 params[1].integer.value = rev;
632 params[2].type = ACPI_TYPE_INTEGER;
633 params[2].integer.value = func;
634 if (argv4) {
635 params[3] = *argv4;
636 } else {
637 params[3].type = ACPI_TYPE_PACKAGE;
638 params[3].package.count = 0;
639 params[3].package.elements = NULL;
640 }
641
642 ret = acpi_evaluate_object(handle, "_DSM", &input, &buf);
643 if (ACPI_SUCCESS(ret))
644 return (union acpi_object *)buf.pointer;
645
646 if (ret != AE_NOT_FOUND)
647 acpi_handle_warn(handle,
648 "failed to evaluate _DSM (0x%x)\n", ret);
649
650 return NULL;
651}
652EXPORT_SYMBOL(acpi_evaluate_dsm);
653
654/**
655 * acpi_check_dsm - check if _DSM method supports requested functions.
656 * @handle: ACPI device handle
657 * @guid: GUID of requested functions, should be 16 bytes at least
658 * @rev: revision number of requested functions
659 * @funcs: bitmap of requested functions
660 *
661 * Evaluate device's _DSM method to check whether it supports requested
662 * functions. Currently only support 64 functions at maximum, should be
663 * enough for now.
664 */
665bool acpi_check_dsm(acpi_handle handle, const guid_t *guid, u64 rev, u64 funcs)
666{
667 int i;
668 u64 mask = 0;
669 union acpi_object *obj;
670
671 if (funcs == 0)
672 return false;
673
674 obj = acpi_evaluate_dsm(handle, guid, rev, 0, NULL);
675 if (!obj)
676 return false;
677
678 /* For compatibility, old BIOSes may return an integer */
679 if (obj->type == ACPI_TYPE_INTEGER)
680 mask = obj->integer.value;
681 else if (obj->type == ACPI_TYPE_BUFFER)
682 for (i = 0; i < obj->buffer.length && i < 8; i++)
683 mask |= (((u64)obj->buffer.pointer[i]) << (i * 8));
684 ACPI_FREE(obj);
685
686 /*
687 * Bit 0 indicates whether there's support for any functions other than
688 * function 0 for the specified GUID and revision.
689 */
690 if ((mask & 0x1) && (mask & funcs) == funcs)
691 return true;
692
693 return false;
694}
695EXPORT_SYMBOL(acpi_check_dsm);
696
697/**
698 * acpi_dev_found - Detect presence of a given ACPI device in the namespace.
699 * @hid: Hardware ID of the device.
700 *
701 * Return %true if the device was present at the moment of invocation.
702 * Note that if the device is pluggable, it may since have disappeared.
703 *
704 * For this function to work, acpi_bus_scan() must have been executed
705 * which happens in the subsys_initcall() subsection. Hence, do not
706 * call from a subsys_initcall() or earlier (use acpi_get_devices()
707 * instead). Calling from module_init() is fine (which is synonymous
708 * with device_initcall()).
709 */
710bool acpi_dev_found(const char *hid)
711{
712 struct acpi_device_bus_id *acpi_device_bus_id;
713 bool found = false;
714
715 mutex_lock(&acpi_device_lock);
716 list_for_each_entry(acpi_device_bus_id, &acpi_bus_id_list, node)
717 if (!strcmp(acpi_device_bus_id->bus_id, hid)) {
718 found = true;
719 break;
720 }
721 mutex_unlock(&acpi_device_lock);
722
723 return found;
724}
725EXPORT_SYMBOL(acpi_dev_found);
726
727struct acpi_dev_match_info {
728 struct acpi_device_id hid[2];
729 const char *uid;
730 s64 hrv;
731};
732
733static int acpi_dev_match_cb(struct device *dev, const void *data)
734{
735 struct acpi_device *adev = to_acpi_device(dev);
736 const struct acpi_dev_match_info *match = data;
737 unsigned long long hrv;
738 acpi_status status;
739
740 if (acpi_match_device_ids(adev, match->hid))
741 return 0;
742
743 if (match->uid && (!adev->pnp.unique_id ||
744 strcmp(adev->pnp.unique_id, match->uid)))
745 return 0;
746
747 if (match->hrv == -1)
748 return 1;
749
750 status = acpi_evaluate_integer(adev->handle, "_HRV", NULL, &hrv);
751 if (ACPI_FAILURE(status))
752 return 0;
753
754 return hrv == match->hrv;
755}
756
757/**
758 * acpi_dev_present - Detect that a given ACPI device is present
759 * @hid: Hardware ID of the device.
760 * @uid: Unique ID of the device, pass NULL to not check _UID
761 * @hrv: Hardware Revision of the device, pass -1 to not check _HRV
762 *
763 * Return %true if a matching device was present at the moment of invocation.
764 * Note that if the device is pluggable, it may since have disappeared.
765 *
766 * Note that unlike acpi_dev_found() this function checks the status
767 * of the device. So for devices which are present in the dsdt, but
768 * which are disabled (their _STA callback returns 0) this function
769 * will return false.
770 *
771 * For this function to work, acpi_bus_scan() must have been executed
772 * which happens in the subsys_initcall() subsection. Hence, do not
773 * call from a subsys_initcall() or earlier (use acpi_get_devices()
774 * instead). Calling from module_init() is fine (which is synonymous
775 * with device_initcall()).
776 */
777bool acpi_dev_present(const char *hid, const char *uid, s64 hrv)
778{
779 struct acpi_dev_match_info match = {};
780 struct device *dev;
781
782 strlcpy(match.hid[0].id, hid, sizeof(match.hid[0].id));
783 match.uid = uid;
784 match.hrv = hrv;
785
786 dev = bus_find_device(&acpi_bus_type, NULL, &match, acpi_dev_match_cb);
787 put_device(dev);
788 return !!dev;
789}
790EXPORT_SYMBOL(acpi_dev_present);
791
792/**
793 * acpi_dev_get_first_match_dev - Return the first match of ACPI device
794 * @hid: Hardware ID of the device.
795 * @uid: Unique ID of the device, pass NULL to not check _UID
796 * @hrv: Hardware Revision of the device, pass -1 to not check _HRV
797 *
798 * Return the first match of ACPI device if a matching device was present
799 * at the moment of invocation, or NULL otherwise.
800 *
801 * The caller is responsible to call put_device() on the returned device.
802 *
803 * See additional information in acpi_dev_present() as well.
804 */
805struct acpi_device *
806acpi_dev_get_first_match_dev(const char *hid, const char *uid, s64 hrv)
807{
808 struct acpi_dev_match_info match = {};
809 struct device *dev;
810
811 strlcpy(match.hid[0].id, hid, sizeof(match.hid[0].id));
812 match.uid = uid;
813 match.hrv = hrv;
814
815 dev = bus_find_device(&acpi_bus_type, NULL, &match, acpi_dev_match_cb);
816 return dev ? to_acpi_device(dev) : NULL;
817}
818EXPORT_SYMBOL(acpi_dev_get_first_match_dev);
819
820/*
821 * acpi_backlight= handling, this is done here rather then in video_detect.c
822 * because __setup cannot be used in modules.
823 */
824char acpi_video_backlight_string[16];
825EXPORT_SYMBOL(acpi_video_backlight_string);
826
827static int __init acpi_backlight(char *str)
828{
829 strlcpy(acpi_video_backlight_string, str,
830 sizeof(acpi_video_backlight_string));
831 return 1;
832}
833__setup("acpi_backlight=", acpi_backlight);
834
835/**
836 * acpi_match_platform_list - Check if the system matches with a given list
837 * @plat: pointer to acpi_platform_list table terminated by a NULL entry
838 *
839 * Return the matched index if the system is found in the platform list.
840 * Otherwise, return a negative error code.
841 */
842int acpi_match_platform_list(const struct acpi_platform_list *plat)
843{
844 struct acpi_table_header hdr;
845 int idx = 0;
846
847 if (acpi_disabled)
848 return -ENODEV;
849
850 for (; plat->oem_id[0]; plat++, idx++) {
851 if (ACPI_FAILURE(acpi_get_table_header(plat->table, 0, &hdr)))
852 continue;
853
854 if (strncmp(plat->oem_id, hdr.oem_id, ACPI_OEM_ID_SIZE))
855 continue;
856
857 if (strncmp(plat->oem_table_id, hdr.oem_table_id, ACPI_OEM_TABLE_ID_SIZE))
858 continue;
859
860 if ((plat->pred == all_versions) ||
861 (plat->pred == less_than_or_equal && hdr.oem_revision <= plat->oem_revision) ||
862 (plat->pred == greater_than_or_equal && hdr.oem_revision >= plat->oem_revision) ||
863 (plat->pred == equal && hdr.oem_revision == plat->oem_revision))
864 return idx;
865 }
866
867 return -ENODEV;
868}
869EXPORT_SYMBOL(acpi_match_platform_list);
1/*
2 * acpi_utils.c - ACPI Utility Functions ($Revision: 10 $)
3 *
4 * Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
5 * Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
6 *
7 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
8 *
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License as published by
11 * the Free Software Foundation; either version 2 of the License, or (at
12 * your option) any later version.
13 *
14 * This program is distributed in the hope that it will be useful, but
15 * WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17 * General Public License for more details.
18 *
19 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
20 */
21
22#include <linux/kernel.h>
23#include <linux/module.h>
24#include <linux/slab.h>
25#include <linux/init.h>
26#include <linux/types.h>
27#include <linux/hardirq.h>
28#include <linux/acpi.h>
29#include <linux/dynamic_debug.h>
30
31#include "internal.h"
32#include "sleep.h"
33
34#define _COMPONENT ACPI_BUS_COMPONENT
35ACPI_MODULE_NAME("utils");
36
37/* --------------------------------------------------------------------------
38 Object Evaluation Helpers
39 -------------------------------------------------------------------------- */
40static void
41acpi_util_eval_error(acpi_handle h, acpi_string p, acpi_status s)
42{
43#ifdef ACPI_DEBUG_OUTPUT
44 char prefix[80] = {'\0'};
45 struct acpi_buffer buffer = {sizeof(prefix), prefix};
46 acpi_get_name(h, ACPI_FULL_PATHNAME, &buffer);
47 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Evaluate [%s.%s]: %s\n",
48 (char *) prefix, p, acpi_format_exception(s)));
49#else
50 return;
51#endif
52}
53
54acpi_status
55acpi_extract_package(union acpi_object *package,
56 struct acpi_buffer *format, struct acpi_buffer *buffer)
57{
58 u32 size_required = 0;
59 u32 tail_offset = 0;
60 char *format_string = NULL;
61 u32 format_count = 0;
62 u32 i = 0;
63 u8 *head = NULL;
64 u8 *tail = NULL;
65
66
67 if (!package || (package->type != ACPI_TYPE_PACKAGE)
68 || (package->package.count < 1)) {
69 printk(KERN_WARNING PREFIX "Invalid package argument\n");
70 return AE_BAD_PARAMETER;
71 }
72
73 if (!format || !format->pointer || (format->length < 1)) {
74 printk(KERN_WARNING PREFIX "Invalid format argument\n");
75 return AE_BAD_PARAMETER;
76 }
77
78 if (!buffer) {
79 printk(KERN_WARNING PREFIX "Invalid buffer argument\n");
80 return AE_BAD_PARAMETER;
81 }
82
83 format_count = (format->length / sizeof(char)) - 1;
84 if (format_count > package->package.count) {
85 printk(KERN_WARNING PREFIX "Format specifies more objects [%d]"
86 " than exist in package [%d].\n",
87 format_count, package->package.count);
88 return AE_BAD_DATA;
89 }
90
91 format_string = format->pointer;
92
93 /*
94 * Calculate size_required.
95 */
96 for (i = 0; i < format_count; i++) {
97
98 union acpi_object *element = &(package->package.elements[i]);
99
100 switch (element->type) {
101
102 case ACPI_TYPE_INTEGER:
103 switch (format_string[i]) {
104 case 'N':
105 size_required += sizeof(u64);
106 tail_offset += sizeof(u64);
107 break;
108 case 'S':
109 size_required +=
110 sizeof(char *) + sizeof(u64) +
111 sizeof(char);
112 tail_offset += sizeof(char *);
113 break;
114 default:
115 printk(KERN_WARNING PREFIX "Invalid package element"
116 " [%d]: got number, expecting"
117 " [%c]\n",
118 i, format_string[i]);
119 return AE_BAD_DATA;
120 break;
121 }
122 break;
123
124 case ACPI_TYPE_STRING:
125 case ACPI_TYPE_BUFFER:
126 switch (format_string[i]) {
127 case 'S':
128 size_required +=
129 sizeof(char *) +
130 (element->string.length * sizeof(char)) +
131 sizeof(char);
132 tail_offset += sizeof(char *);
133 break;
134 case 'B':
135 size_required +=
136 sizeof(u8 *) + element->buffer.length;
137 tail_offset += sizeof(u8 *);
138 break;
139 default:
140 printk(KERN_WARNING PREFIX "Invalid package element"
141 " [%d] got string/buffer,"
142 " expecting [%c]\n",
143 i, format_string[i]);
144 return AE_BAD_DATA;
145 break;
146 }
147 break;
148 case ACPI_TYPE_LOCAL_REFERENCE:
149 switch (format_string[i]) {
150 case 'R':
151 size_required += sizeof(void *);
152 tail_offset += sizeof(void *);
153 break;
154 default:
155 printk(KERN_WARNING PREFIX "Invalid package element"
156 " [%d] got reference,"
157 " expecting [%c]\n",
158 i, format_string[i]);
159 return AE_BAD_DATA;
160 break;
161 }
162 break;
163
164 case ACPI_TYPE_PACKAGE:
165 default:
166 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
167 "Found unsupported element at index=%d\n",
168 i));
169 /* TBD: handle nested packages... */
170 return AE_SUPPORT;
171 break;
172 }
173 }
174
175 /*
176 * Validate output buffer.
177 */
178 if (buffer->length == ACPI_ALLOCATE_BUFFER) {
179 buffer->pointer = ACPI_ALLOCATE_ZEROED(size_required);
180 if (!buffer->pointer)
181 return AE_NO_MEMORY;
182 buffer->length = size_required;
183 } else {
184 if (buffer->length < size_required) {
185 buffer->length = size_required;
186 return AE_BUFFER_OVERFLOW;
187 } else if (buffer->length != size_required ||
188 !buffer->pointer) {
189 return AE_BAD_PARAMETER;
190 }
191 }
192
193 head = buffer->pointer;
194 tail = buffer->pointer + tail_offset;
195
196 /*
197 * Extract package data.
198 */
199 for (i = 0; i < format_count; i++) {
200
201 u8 **pointer = NULL;
202 union acpi_object *element = &(package->package.elements[i]);
203
204 switch (element->type) {
205
206 case ACPI_TYPE_INTEGER:
207 switch (format_string[i]) {
208 case 'N':
209 *((u64 *) head) =
210 element->integer.value;
211 head += sizeof(u64);
212 break;
213 case 'S':
214 pointer = (u8 **) head;
215 *pointer = tail;
216 *((u64 *) tail) =
217 element->integer.value;
218 head += sizeof(u64 *);
219 tail += sizeof(u64);
220 /* NULL terminate string */
221 *tail = (char)0;
222 tail += sizeof(char);
223 break;
224 default:
225 /* Should never get here */
226 break;
227 }
228 break;
229
230 case ACPI_TYPE_STRING:
231 case ACPI_TYPE_BUFFER:
232 switch (format_string[i]) {
233 case 'S':
234 pointer = (u8 **) head;
235 *pointer = tail;
236 memcpy(tail, element->string.pointer,
237 element->string.length);
238 head += sizeof(char *);
239 tail += element->string.length * sizeof(char);
240 /* NULL terminate string */
241 *tail = (char)0;
242 tail += sizeof(char);
243 break;
244 case 'B':
245 pointer = (u8 **) head;
246 *pointer = tail;
247 memcpy(tail, element->buffer.pointer,
248 element->buffer.length);
249 head += sizeof(u8 *);
250 tail += element->buffer.length;
251 break;
252 default:
253 /* Should never get here */
254 break;
255 }
256 break;
257 case ACPI_TYPE_LOCAL_REFERENCE:
258 switch (format_string[i]) {
259 case 'R':
260 *(void **)head =
261 (void *)element->reference.handle;
262 head += sizeof(void *);
263 break;
264 default:
265 /* Should never get here */
266 break;
267 }
268 break;
269 case ACPI_TYPE_PACKAGE:
270 /* TBD: handle nested packages... */
271 default:
272 /* Should never get here */
273 break;
274 }
275 }
276
277 return AE_OK;
278}
279
280EXPORT_SYMBOL(acpi_extract_package);
281
282acpi_status
283acpi_evaluate_integer(acpi_handle handle,
284 acpi_string pathname,
285 struct acpi_object_list *arguments, unsigned long long *data)
286{
287 acpi_status status = AE_OK;
288 union acpi_object element;
289 struct acpi_buffer buffer = { 0, NULL };
290
291 if (!data)
292 return AE_BAD_PARAMETER;
293
294 buffer.length = sizeof(union acpi_object);
295 buffer.pointer = &element;
296 status = acpi_evaluate_object(handle, pathname, arguments, &buffer);
297 if (ACPI_FAILURE(status)) {
298 acpi_util_eval_error(handle, pathname, status);
299 return status;
300 }
301
302 if (element.type != ACPI_TYPE_INTEGER) {
303 acpi_util_eval_error(handle, pathname, AE_BAD_DATA);
304 return AE_BAD_DATA;
305 }
306
307 *data = element.integer.value;
308
309 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Return value [%llu]\n", *data));
310
311 return AE_OK;
312}
313
314EXPORT_SYMBOL(acpi_evaluate_integer);
315
316acpi_status
317acpi_evaluate_reference(acpi_handle handle,
318 acpi_string pathname,
319 struct acpi_object_list *arguments,
320 struct acpi_handle_list *list)
321{
322 acpi_status status = AE_OK;
323 union acpi_object *package = NULL;
324 union acpi_object *element = NULL;
325 struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
326 u32 i = 0;
327
328
329 if (!list) {
330 return AE_BAD_PARAMETER;
331 }
332
333 /* Evaluate object. */
334
335 status = acpi_evaluate_object(handle, pathname, arguments, &buffer);
336 if (ACPI_FAILURE(status))
337 goto end;
338
339 package = buffer.pointer;
340
341 if ((buffer.length == 0) || !package) {
342 status = AE_BAD_DATA;
343 acpi_util_eval_error(handle, pathname, status);
344 goto end;
345 }
346 if (package->type != ACPI_TYPE_PACKAGE) {
347 status = AE_BAD_DATA;
348 acpi_util_eval_error(handle, pathname, status);
349 goto end;
350 }
351 if (!package->package.count) {
352 status = AE_BAD_DATA;
353 acpi_util_eval_error(handle, pathname, status);
354 goto end;
355 }
356
357 if (package->package.count > ACPI_MAX_HANDLES) {
358 return AE_NO_MEMORY;
359 }
360 list->count = package->package.count;
361
362 /* Extract package data. */
363
364 for (i = 0; i < list->count; i++) {
365
366 element = &(package->package.elements[i]);
367
368 if (element->type != ACPI_TYPE_LOCAL_REFERENCE) {
369 status = AE_BAD_DATA;
370 acpi_util_eval_error(handle, pathname, status);
371 break;
372 }
373
374 if (!element->reference.handle) {
375 status = AE_NULL_ENTRY;
376 acpi_util_eval_error(handle, pathname, status);
377 break;
378 }
379 /* Get the acpi_handle. */
380
381 list->handles[i] = element->reference.handle;
382 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found reference [%p]\n",
383 list->handles[i]));
384 }
385
386 end:
387 if (ACPI_FAILURE(status)) {
388 list->count = 0;
389 //kfree(list->handles);
390 }
391
392 kfree(buffer.pointer);
393
394 return status;
395}
396
397EXPORT_SYMBOL(acpi_evaluate_reference);
398
399acpi_status
400acpi_get_physical_device_location(acpi_handle handle, struct acpi_pld_info **pld)
401{
402 acpi_status status;
403 struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
404 union acpi_object *output;
405
406 status = acpi_evaluate_object(handle, "_PLD", NULL, &buffer);
407
408 if (ACPI_FAILURE(status))
409 return status;
410
411 output = buffer.pointer;
412
413 if (!output || output->type != ACPI_TYPE_PACKAGE
414 || !output->package.count
415 || output->package.elements[0].type != ACPI_TYPE_BUFFER
416 || output->package.elements[0].buffer.length < ACPI_PLD_REV1_BUFFER_SIZE) {
417 status = AE_TYPE;
418 goto out;
419 }
420
421 status = acpi_decode_pld_buffer(
422 output->package.elements[0].buffer.pointer,
423 output->package.elements[0].buffer.length,
424 pld);
425
426out:
427 kfree(buffer.pointer);
428 return status;
429}
430EXPORT_SYMBOL(acpi_get_physical_device_location);
431
432/**
433 * acpi_evaluate_ost: Evaluate _OST for hotplug operations
434 * @handle: ACPI device handle
435 * @source_event: source event code
436 * @status_code: status code
437 * @status_buf: optional detailed information (NULL if none)
438 *
439 * Evaluate _OST for hotplug operations. All ACPI hotplug handlers
440 * must call this function when evaluating _OST for hotplug operations.
441 * When the platform does not support _OST, this function has no effect.
442 */
443acpi_status
444acpi_evaluate_ost(acpi_handle handle, u32 source_event, u32 status_code,
445 struct acpi_buffer *status_buf)
446{
447 union acpi_object params[3] = {
448 {.type = ACPI_TYPE_INTEGER,},
449 {.type = ACPI_TYPE_INTEGER,},
450 {.type = ACPI_TYPE_BUFFER,}
451 };
452 struct acpi_object_list arg_list = {3, params};
453
454 params[0].integer.value = source_event;
455 params[1].integer.value = status_code;
456 if (status_buf != NULL) {
457 params[2].buffer.pointer = status_buf->pointer;
458 params[2].buffer.length = status_buf->length;
459 } else {
460 params[2].buffer.pointer = NULL;
461 params[2].buffer.length = 0;
462 }
463
464 return acpi_evaluate_object(handle, "_OST", &arg_list, NULL);
465}
466EXPORT_SYMBOL(acpi_evaluate_ost);
467
468/**
469 * acpi_handle_path: Return the object path of handle
470 *
471 * Caller must free the returned buffer
472 */
473static char *acpi_handle_path(acpi_handle handle)
474{
475 struct acpi_buffer buffer = {
476 .length = ACPI_ALLOCATE_BUFFER,
477 .pointer = NULL
478 };
479
480 if (in_interrupt() ||
481 acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer) != AE_OK)
482 return NULL;
483 return buffer.pointer;
484}
485
486/**
487 * acpi_handle_printk: Print message with ACPI prefix and object path
488 *
489 * This function is called through acpi_handle_<level> macros and prints
490 * a message with ACPI prefix and object path. This function acquires
491 * the global namespace mutex to obtain an object path. In interrupt
492 * context, it shows the object path as <n/a>.
493 */
494void
495acpi_handle_printk(const char *level, acpi_handle handle, 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 printk("%sACPI: %s: %pV", level, path ? path : "<n/a>" , &vaf);
507
508 va_end(args);
509 kfree(path);
510}
511EXPORT_SYMBOL(acpi_handle_printk);
512
513#if defined(CONFIG_DYNAMIC_DEBUG)
514/**
515 * __acpi_handle_debug: pr_debug with ACPI prefix and object path
516 *
517 * This function is called through acpi_handle_debug macro and debug
518 * prints a message with ACPI prefix and object path. This function
519 * acquires the global namespace mutex to obtain an object path. In
520 * interrupt context, it shows the object path as <n/a>.
521 */
522void
523__acpi_handle_debug(struct _ddebug *descriptor, acpi_handle handle,
524 const char *fmt, ...)
525{
526 struct va_format vaf;
527 va_list args;
528 const char *path;
529
530 va_start(args, fmt);
531 vaf.fmt = fmt;
532 vaf.va = &args;
533
534 path = acpi_handle_path(handle);
535 __dynamic_pr_debug(descriptor, "ACPI: %s: %pV", path ? path : "<n/a>", &vaf);
536
537 va_end(args);
538 kfree(path);
539}
540EXPORT_SYMBOL(__acpi_handle_debug);
541#endif
542
543/**
544 * acpi_has_method: Check whether @handle has a method named @name
545 * @handle: ACPI device handle
546 * @name: name of object or method
547 *
548 * Check whether @handle has a method named @name.
549 */
550bool acpi_has_method(acpi_handle handle, char *name)
551{
552 acpi_handle tmp;
553
554 return ACPI_SUCCESS(acpi_get_handle(handle, name, &tmp));
555}
556EXPORT_SYMBOL(acpi_has_method);
557
558acpi_status acpi_execute_simple_method(acpi_handle handle, char *method,
559 u64 arg)
560{
561 union acpi_object obj = { .type = ACPI_TYPE_INTEGER };
562 struct acpi_object_list arg_list = { .count = 1, .pointer = &obj, };
563
564 obj.integer.value = arg;
565
566 return acpi_evaluate_object(handle, method, &arg_list, NULL);
567}
568EXPORT_SYMBOL(acpi_execute_simple_method);
569
570/**
571 * acpi_evaluate_ej0: Evaluate _EJ0 method for hotplug operations
572 * @handle: ACPI device handle
573 *
574 * Evaluate device's _EJ0 method for hotplug operations.
575 */
576acpi_status acpi_evaluate_ej0(acpi_handle handle)
577{
578 acpi_status status;
579
580 status = acpi_execute_simple_method(handle, "_EJ0", 1);
581 if (status == AE_NOT_FOUND)
582 acpi_handle_warn(handle, "No _EJ0 support for device\n");
583 else if (ACPI_FAILURE(status))
584 acpi_handle_warn(handle, "Eject failed (0x%x)\n", status);
585
586 return status;
587}
588
589/**
590 * acpi_evaluate_lck: Evaluate _LCK method to lock/unlock device
591 * @handle: ACPI device handle
592 * @lock: lock device if non-zero, otherwise unlock device
593 *
594 * Evaluate device's _LCK method if present to lock/unlock device
595 */
596acpi_status acpi_evaluate_lck(acpi_handle handle, int lock)
597{
598 acpi_status status;
599
600 status = acpi_execute_simple_method(handle, "_LCK", !!lock);
601 if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {
602 if (lock)
603 acpi_handle_warn(handle,
604 "Locking device failed (0x%x)\n", status);
605 else
606 acpi_handle_warn(handle,
607 "Unlocking device failed (0x%x)\n", status);
608 }
609
610 return status;
611}
612
613/**
614 * acpi_evaluate_dsm - evaluate device's _DSM method
615 * @handle: ACPI device handle
616 * @uuid: UUID of requested functions, should be 16 bytes
617 * @rev: revision number of requested function
618 * @func: requested function number
619 * @argv4: the function specific parameter
620 *
621 * Evaluate device's _DSM method with specified UUID, revision id and
622 * function number. Caller needs to free the returned object.
623 *
624 * Though ACPI defines the fourth parameter for _DSM should be a package,
625 * some old BIOSes do expect a buffer or an integer etc.
626 */
627union acpi_object *
628acpi_evaluate_dsm(acpi_handle handle, const u8 *uuid, int rev, int func,
629 union acpi_object *argv4)
630{
631 acpi_status ret;
632 struct acpi_buffer buf = {ACPI_ALLOCATE_BUFFER, NULL};
633 union acpi_object params[4];
634 struct acpi_object_list input = {
635 .count = 4,
636 .pointer = params,
637 };
638
639 params[0].type = ACPI_TYPE_BUFFER;
640 params[0].buffer.length = 16;
641 params[0].buffer.pointer = (char *)uuid;
642 params[1].type = ACPI_TYPE_INTEGER;
643 params[1].integer.value = rev;
644 params[2].type = ACPI_TYPE_INTEGER;
645 params[2].integer.value = func;
646 if (argv4) {
647 params[3] = *argv4;
648 } else {
649 params[3].type = ACPI_TYPE_PACKAGE;
650 params[3].package.count = 0;
651 params[3].package.elements = NULL;
652 }
653
654 ret = acpi_evaluate_object(handle, "_DSM", &input, &buf);
655 if (ACPI_SUCCESS(ret))
656 return (union acpi_object *)buf.pointer;
657
658 if (ret != AE_NOT_FOUND)
659 acpi_handle_warn(handle,
660 "failed to evaluate _DSM (0x%x)\n", ret);
661
662 return NULL;
663}
664EXPORT_SYMBOL(acpi_evaluate_dsm);
665
666/**
667 * acpi_check_dsm - check if _DSM method supports requested functions.
668 * @handle: ACPI device handle
669 * @uuid: UUID of requested functions, should be 16 bytes at least
670 * @rev: revision number of requested functions
671 * @funcs: bitmap of requested functions
672 *
673 * Evaluate device's _DSM method to check whether it supports requested
674 * functions. Currently only support 64 functions at maximum, should be
675 * enough for now.
676 */
677bool acpi_check_dsm(acpi_handle handle, const u8 *uuid, int rev, u64 funcs)
678{
679 int i;
680 u64 mask = 0;
681 union acpi_object *obj;
682
683 if (funcs == 0)
684 return false;
685
686 obj = acpi_evaluate_dsm(handle, uuid, rev, 0, NULL);
687 if (!obj)
688 return false;
689
690 /* For compatibility, old BIOSes may return an integer */
691 if (obj->type == ACPI_TYPE_INTEGER)
692 mask = obj->integer.value;
693 else if (obj->type == ACPI_TYPE_BUFFER)
694 for (i = 0; i < obj->buffer.length && i < 8; i++)
695 mask |= (((u64)obj->buffer.pointer[i]) << (i * 8));
696 ACPI_FREE(obj);
697
698 /*
699 * Bit 0 indicates whether there's support for any functions other than
700 * function 0 for the specified UUID and revision.
701 */
702 if ((mask & 0x1) && (mask & funcs) == funcs)
703 return true;
704
705 return false;
706}
707EXPORT_SYMBOL(acpi_check_dsm);
708
709/**
710 * acpi_dev_present - Detect presence of a given ACPI device in the system.
711 * @hid: Hardware ID of the device.
712 *
713 * Return %true if the device was present at the moment of invocation.
714 * Note that if the device is pluggable, it may since have disappeared.
715 *
716 * For this function to work, acpi_bus_scan() must have been executed
717 * which happens in the subsys_initcall() subsection. Hence, do not
718 * call from a subsys_initcall() or earlier (use acpi_get_devices()
719 * instead). Calling from module_init() is fine (which is synonymous
720 * with device_initcall()).
721 */
722bool acpi_dev_present(const char *hid)
723{
724 struct acpi_device_bus_id *acpi_device_bus_id;
725 bool found = false;
726
727 mutex_lock(&acpi_device_lock);
728 list_for_each_entry(acpi_device_bus_id, &acpi_bus_id_list, node)
729 if (!strcmp(acpi_device_bus_id->bus_id, hid)) {
730 found = true;
731 break;
732 }
733 mutex_unlock(&acpi_device_lock);
734
735 return found;
736}
737EXPORT_SYMBOL(acpi_dev_present);
738
739/*
740 * acpi_backlight= handling, this is done here rather then in video_detect.c
741 * because __setup cannot be used in modules.
742 */
743char acpi_video_backlight_string[16];
744EXPORT_SYMBOL(acpi_video_backlight_string);
745
746static int __init acpi_backlight(char *str)
747{
748 strlcpy(acpi_video_backlight_string, str,
749 sizeof(acpi_video_backlight_string));
750 return 1;
751}
752__setup("acpi_backlight=", acpi_backlight);