Merge tag 'media/v3.18-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab...
[firefly-linux-kernel-4.4.55.git] / drivers / acpi / utils.c
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  *  You should have received a copy of the GNU General Public License along
20  *  with this program; if not, write to the Free Software Foundation, Inc.,
21  *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
22  *
23  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
24  */
25
26 #include <linux/kernel.h>
27 #include <linux/module.h>
28 #include <linux/slab.h>
29 #include <linux/init.h>
30 #include <linux/types.h>
31 #include <linux/hardirq.h>
32 #include <linux/acpi.h>
33 #include <linux/dynamic_debug.h>
34
35 #include "internal.h"
36
37 #define _COMPONENT              ACPI_BUS_COMPONENT
38 ACPI_MODULE_NAME("utils");
39
40 /* --------------------------------------------------------------------------
41                             Object Evaluation Helpers
42    -------------------------------------------------------------------------- */
43 static void
44 acpi_util_eval_error(acpi_handle h, acpi_string p, acpi_status s)
45 {
46 #ifdef ACPI_DEBUG_OUTPUT
47         char prefix[80] = {'\0'};
48         struct acpi_buffer buffer = {sizeof(prefix), prefix};
49         acpi_get_name(h, ACPI_FULL_PATHNAME, &buffer);
50         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Evaluate [%s.%s]: %s\n",
51                 (char *) prefix, p, acpi_format_exception(s)));
52 #else
53         return;
54 #endif
55 }
56
57 acpi_status
58 acpi_extract_package(union acpi_object *package,
59                      struct acpi_buffer *format, struct acpi_buffer *buffer)
60 {
61         u32 size_required = 0;
62         u32 tail_offset = 0;
63         char *format_string = NULL;
64         u32 format_count = 0;
65         u32 i = 0;
66         u8 *head = NULL;
67         u8 *tail = NULL;
68
69
70         if (!package || (package->type != ACPI_TYPE_PACKAGE)
71             || (package->package.count < 1)) {
72                 printk(KERN_WARNING PREFIX "Invalid package argument\n");
73                 return AE_BAD_PARAMETER;
74         }
75
76         if (!format || !format->pointer || (format->length < 1)) {
77                 printk(KERN_WARNING PREFIX "Invalid format argument\n");
78                 return AE_BAD_PARAMETER;
79         }
80
81         if (!buffer) {
82                 printk(KERN_WARNING PREFIX "Invalid buffer argument\n");
83                 return AE_BAD_PARAMETER;
84         }
85
86         format_count = (format->length / sizeof(char)) - 1;
87         if (format_count > package->package.count) {
88                 printk(KERN_WARNING PREFIX "Format specifies more objects [%d]"
89                               " than exist in package [%d].\n",
90                               format_count, package->package.count);
91                 return AE_BAD_DATA;
92         }
93
94         format_string = format->pointer;
95
96         /*
97          * Calculate size_required.
98          */
99         for (i = 0; i < format_count; i++) {
100
101                 union acpi_object *element = &(package->package.elements[i]);
102
103                 switch (element->type) {
104
105                 case ACPI_TYPE_INTEGER:
106                         switch (format_string[i]) {
107                         case 'N':
108                                 size_required += sizeof(u64);
109                                 tail_offset += sizeof(u64);
110                                 break;
111                         case 'S':
112                                 size_required +=
113                                     sizeof(char *) + sizeof(u64) +
114                                     sizeof(char);
115                                 tail_offset += sizeof(char *);
116                                 break;
117                         default:
118                                 printk(KERN_WARNING PREFIX "Invalid package element"
119                                               " [%d]: got number, expecting"
120                                               " [%c]\n",
121                                               i, format_string[i]);
122                                 return AE_BAD_DATA;
123                                 break;
124                         }
125                         break;
126
127                 case ACPI_TYPE_STRING:
128                 case ACPI_TYPE_BUFFER:
129                         switch (format_string[i]) {
130                         case 'S':
131                                 size_required +=
132                                     sizeof(char *) +
133                                     (element->string.length * sizeof(char)) +
134                                     sizeof(char);
135                                 tail_offset += sizeof(char *);
136                                 break;
137                         case 'B':
138                                 size_required +=
139                                     sizeof(u8 *) +
140                                     (element->buffer.length * sizeof(u8));
141                                 tail_offset += sizeof(u8 *);
142                                 break;
143                         default:
144                                 printk(KERN_WARNING PREFIX "Invalid package element"
145                                               " [%d] got string/buffer,"
146                                               " expecting [%c]\n",
147                                               i, format_string[i]);
148                                 return AE_BAD_DATA;
149                                 break;
150                         }
151                         break;
152                 case ACPI_TYPE_LOCAL_REFERENCE:
153                         switch (format_string[i]) {
154                         case 'R':
155                                 size_required += sizeof(void *);
156                                 tail_offset += sizeof(void *);
157                                 break;
158                         default:
159                                 printk(KERN_WARNING PREFIX "Invalid package element"
160                                               " [%d] got reference,"
161                                               " expecting [%c]\n",
162                                               i, format_string[i]);
163                                 return AE_BAD_DATA;
164                                 break;
165                         }
166                         break;
167
168                 case ACPI_TYPE_PACKAGE:
169                 default:
170                         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
171                                           "Found unsupported element at index=%d\n",
172                                           i));
173                         /* TBD: handle nested packages... */
174                         return AE_SUPPORT;
175                         break;
176                 }
177         }
178
179         /*
180          * Validate output buffer.
181          */
182         if (buffer->length == ACPI_ALLOCATE_BUFFER) {
183                 buffer->pointer = ACPI_ALLOCATE_ZEROED(size_required);
184                 if (!buffer->pointer)
185                         return AE_NO_MEMORY;
186                 buffer->length = size_required;
187         } else {
188                 if (buffer->length < size_required) {
189                         buffer->length = size_required;
190                         return AE_BUFFER_OVERFLOW;
191                 } else if (buffer->length != size_required ||
192                            !buffer->pointer) {
193                         return AE_BAD_PARAMETER;
194                 }
195         }
196
197         head = buffer->pointer;
198         tail = buffer->pointer + tail_offset;
199
200         /*
201          * Extract package data.
202          */
203         for (i = 0; i < format_count; i++) {
204
205                 u8 **pointer = NULL;
206                 union acpi_object *element = &(package->package.elements[i]);
207
208                 if (!element) {
209                         return AE_BAD_DATA;
210                 }
211
212                 switch (element->type) {
213
214                 case ACPI_TYPE_INTEGER:
215                         switch (format_string[i]) {
216                         case 'N':
217                                 *((u64 *) head) =
218                                     element->integer.value;
219                                 head += sizeof(u64);
220                                 break;
221                         case 'S':
222                                 pointer = (u8 **) head;
223                                 *pointer = tail;
224                                 *((u64 *) tail) =
225                                     element->integer.value;
226                                 head += sizeof(u64 *);
227                                 tail += sizeof(u64);
228                                 /* NULL terminate string */
229                                 *tail = (char)0;
230                                 tail += sizeof(char);
231                                 break;
232                         default:
233                                 /* Should never get here */
234                                 break;
235                         }
236                         break;
237
238                 case ACPI_TYPE_STRING:
239                 case ACPI_TYPE_BUFFER:
240                         switch (format_string[i]) {
241                         case 'S':
242                                 pointer = (u8 **) head;
243                                 *pointer = tail;
244                                 memcpy(tail, element->string.pointer,
245                                        element->string.length);
246                                 head += sizeof(char *);
247                                 tail += element->string.length * sizeof(char);
248                                 /* NULL terminate string */
249                                 *tail = (char)0;
250                                 tail += sizeof(char);
251                                 break;
252                         case 'B':
253                                 pointer = (u8 **) head;
254                                 *pointer = tail;
255                                 memcpy(tail, element->buffer.pointer,
256                                        element->buffer.length);
257                                 head += sizeof(u8 *);
258                                 tail += element->buffer.length * sizeof(u8);
259                                 break;
260                         default:
261                                 /* Should never get here */
262                                 break;
263                         }
264                         break;
265                 case ACPI_TYPE_LOCAL_REFERENCE:
266                         switch (format_string[i]) {
267                         case 'R':
268                                 *(void **)head =
269                                     (void *)element->reference.handle;
270                                 head += sizeof(void *);
271                                 break;
272                         default:
273                                 /* Should never get here */
274                                 break;
275                         }
276                         break;
277                 case ACPI_TYPE_PACKAGE:
278                         /* TBD: handle nested packages... */
279                 default:
280                         /* Should never get here */
281                         break;
282                 }
283         }
284
285         return AE_OK;
286 }
287
288 EXPORT_SYMBOL(acpi_extract_package);
289
290 acpi_status
291 acpi_evaluate_integer(acpi_handle handle,
292                       acpi_string pathname,
293                       struct acpi_object_list *arguments, unsigned long long *data)
294 {
295         acpi_status status = AE_OK;
296         union acpi_object element;
297         struct acpi_buffer buffer = { 0, NULL };
298
299         if (!data)
300                 return AE_BAD_PARAMETER;
301
302         buffer.length = sizeof(union acpi_object);
303         buffer.pointer = &element;
304         status = acpi_evaluate_object(handle, pathname, arguments, &buffer);
305         if (ACPI_FAILURE(status)) {
306                 acpi_util_eval_error(handle, pathname, status);
307                 return status;
308         }
309
310         if (element.type != ACPI_TYPE_INTEGER) {
311                 acpi_util_eval_error(handle, pathname, AE_BAD_DATA);
312                 return AE_BAD_DATA;
313         }
314
315         *data = element.integer.value;
316
317         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Return value [%llu]\n", *data));
318
319         return AE_OK;
320 }
321
322 EXPORT_SYMBOL(acpi_evaluate_integer);
323
324 acpi_status
325 acpi_evaluate_reference(acpi_handle handle,
326                         acpi_string pathname,
327                         struct acpi_object_list *arguments,
328                         struct acpi_handle_list *list)
329 {
330         acpi_status status = AE_OK;
331         union acpi_object *package = NULL;
332         union acpi_object *element = NULL;
333         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
334         u32 i = 0;
335
336
337         if (!list) {
338                 return AE_BAD_PARAMETER;
339         }
340
341         /* Evaluate object. */
342
343         status = acpi_evaluate_object(handle, pathname, arguments, &buffer);
344         if (ACPI_FAILURE(status))
345                 goto end;
346
347         package = buffer.pointer;
348
349         if ((buffer.length == 0) || !package) {
350                 printk(KERN_ERR PREFIX "No return object (len %X ptr %p)\n",
351                             (unsigned)buffer.length, package);
352                 status = AE_BAD_DATA;
353                 acpi_util_eval_error(handle, pathname, status);
354                 goto end;
355         }
356         if (package->type != ACPI_TYPE_PACKAGE) {
357                 printk(KERN_ERR PREFIX "Expecting a [Package], found type %X\n",
358                             package->type);
359                 status = AE_BAD_DATA;
360                 acpi_util_eval_error(handle, pathname, status);
361                 goto end;
362         }
363         if (!package->package.count) {
364                 printk(KERN_ERR PREFIX "[Package] has zero elements (%p)\n",
365                             package);
366                 status = AE_BAD_DATA;
367                 acpi_util_eval_error(handle, pathname, status);
368                 goto end;
369         }
370
371         if (package->package.count > ACPI_MAX_HANDLES) {
372                 return AE_NO_MEMORY;
373         }
374         list->count = package->package.count;
375
376         /* Extract package data. */
377
378         for (i = 0; i < list->count; i++) {
379
380                 element = &(package->package.elements[i]);
381
382                 if (element->type != ACPI_TYPE_LOCAL_REFERENCE) {
383                         status = AE_BAD_DATA;
384                         printk(KERN_ERR PREFIX
385                                     "Expecting a [Reference] package element, found type %X\n",
386                                     element->type);
387                         acpi_util_eval_error(handle, pathname, status);
388                         break;
389                 }
390
391                 if (!element->reference.handle) {
392                         printk(KERN_WARNING PREFIX "Invalid reference in"
393                                " package %s\n", pathname);
394                         status = AE_NULL_ENTRY;
395                         break;
396                 }
397                 /* Get the  acpi_handle. */
398
399                 list->handles[i] = element->reference.handle;
400                 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found reference [%p]\n",
401                                   list->handles[i]));
402         }
403
404       end:
405         if (ACPI_FAILURE(status)) {
406                 list->count = 0;
407                 //kfree(list->handles);
408         }
409
410         kfree(buffer.pointer);
411
412         return status;
413 }
414
415 EXPORT_SYMBOL(acpi_evaluate_reference);
416
417 acpi_status
418 acpi_get_physical_device_location(acpi_handle handle, struct acpi_pld_info **pld)
419 {
420         acpi_status status;
421         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
422         union acpi_object *output;
423
424         status = acpi_evaluate_object(handle, "_PLD", NULL, &buffer);
425
426         if (ACPI_FAILURE(status))
427                 return status;
428
429         output = buffer.pointer;
430
431         if (!output || output->type != ACPI_TYPE_PACKAGE
432             || !output->package.count
433             || output->package.elements[0].type != ACPI_TYPE_BUFFER
434             || output->package.elements[0].buffer.length < ACPI_PLD_REV1_BUFFER_SIZE) {
435                 status = AE_TYPE;
436                 goto out;
437         }
438
439         status = acpi_decode_pld_buffer(
440                         output->package.elements[0].buffer.pointer,
441                         output->package.elements[0].buffer.length,
442                         pld);
443
444 out:
445         kfree(buffer.pointer);
446         return status;
447 }
448 EXPORT_SYMBOL(acpi_get_physical_device_location);
449
450 /**
451  * acpi_evaluate_ost: Evaluate _OST for hotplug operations
452  * @handle: ACPI device handle
453  * @source_event: source event code
454  * @status_code: status code
455  * @status_buf: optional detailed information (NULL if none)
456  *
457  * Evaluate _OST for hotplug operations. All ACPI hotplug handlers
458  * must call this function when evaluating _OST for hotplug operations.
459  * When the platform does not support _OST, this function has no effect.
460  */
461 acpi_status
462 acpi_evaluate_ost(acpi_handle handle, u32 source_event, u32 status_code,
463                   struct acpi_buffer *status_buf)
464 {
465         union acpi_object params[3] = {
466                 {.type = ACPI_TYPE_INTEGER,},
467                 {.type = ACPI_TYPE_INTEGER,},
468                 {.type = ACPI_TYPE_BUFFER,}
469         };
470         struct acpi_object_list arg_list = {3, params};
471
472         params[0].integer.value = source_event;
473         params[1].integer.value = status_code;
474         if (status_buf != NULL) {
475                 params[2].buffer.pointer = status_buf->pointer;
476                 params[2].buffer.length = status_buf->length;
477         } else {
478                 params[2].buffer.pointer = NULL;
479                 params[2].buffer.length = 0;
480         }
481
482         return acpi_evaluate_object(handle, "_OST", &arg_list, NULL);
483 }
484 EXPORT_SYMBOL(acpi_evaluate_ost);
485
486 /**
487  * acpi_handle_path: Return the object path of handle
488  *
489  * Caller must free the returned buffer
490  */
491 static char *acpi_handle_path(acpi_handle handle)
492 {
493         struct acpi_buffer buffer = {
494                 .length = ACPI_ALLOCATE_BUFFER,
495                 .pointer = NULL
496         };
497
498         if (in_interrupt() ||
499             acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer) != AE_OK)
500                 return NULL;
501         return buffer.pointer;
502 }
503
504 /**
505  * acpi_handle_printk: Print message with ACPI prefix and object path
506  *
507  * This function is called through acpi_handle_<level> macros and prints
508  * a message with ACPI prefix and object path.  This function acquires
509  * the global namespace mutex to obtain an object path.  In interrupt
510  * context, it shows the object path as <n/a>.
511  */
512 void
513 acpi_handle_printk(const char *level, acpi_handle handle, const char *fmt, ...)
514 {
515         struct va_format vaf;
516         va_list args;
517         const char *path;
518
519         va_start(args, fmt);
520         vaf.fmt = fmt;
521         vaf.va = &args;
522
523         path = acpi_handle_path(handle);
524         printk("%sACPI: %s: %pV", level, path ? path : "<n/a>" , &vaf);
525
526         va_end(args);
527         kfree(path);
528 }
529 EXPORT_SYMBOL(acpi_handle_printk);
530
531 #if defined(CONFIG_DYNAMIC_DEBUG)
532 /**
533  * __acpi_handle_debug: pr_debug with ACPI prefix and object path
534  *
535  * This function is called through acpi_handle_debug macro and debug
536  * prints a message with ACPI prefix and object path. This function
537  * acquires the global namespace mutex to obtain an object path.  In
538  * interrupt context, it shows the object path as <n/a>.
539  */
540 void
541 __acpi_handle_debug(struct _ddebug *descriptor, acpi_handle handle,
542                     const char *fmt, ...)
543 {
544         struct va_format vaf;
545         va_list args;
546         const char *path;
547
548         va_start(args, fmt);
549         vaf.fmt = fmt;
550         vaf.va = &args;
551
552         path = acpi_handle_path(handle);
553         __dynamic_pr_debug(descriptor, "ACPI: %s: %pV", path ? path : "<n/a>", &vaf);
554
555         va_end(args);
556         kfree(path);
557 }
558 EXPORT_SYMBOL(__acpi_handle_debug);
559 #endif
560
561 /**
562  * acpi_has_method: Check whether @handle has a method named @name
563  * @handle: ACPI device handle
564  * @name: name of object or method
565  *
566  * Check whether @handle has a method named @name.
567  */
568 bool acpi_has_method(acpi_handle handle, char *name)
569 {
570         acpi_handle tmp;
571
572         return ACPI_SUCCESS(acpi_get_handle(handle, name, &tmp));
573 }
574 EXPORT_SYMBOL(acpi_has_method);
575
576 acpi_status acpi_execute_simple_method(acpi_handle handle, char *method,
577                                        u64 arg)
578 {
579         union acpi_object obj = { .type = ACPI_TYPE_INTEGER };
580         struct acpi_object_list arg_list = { .count = 1, .pointer = &obj, };
581
582         obj.integer.value = arg;
583
584         return acpi_evaluate_object(handle, method, &arg_list, NULL);
585 }
586 EXPORT_SYMBOL(acpi_execute_simple_method);
587
588 /**
589  * acpi_evaluate_ej0: Evaluate _EJ0 method for hotplug operations
590  * @handle: ACPI device handle
591  *
592  * Evaluate device's _EJ0 method for hotplug operations.
593  */
594 acpi_status acpi_evaluate_ej0(acpi_handle handle)
595 {
596         acpi_status status;
597
598         status = acpi_execute_simple_method(handle, "_EJ0", 1);
599         if (status == AE_NOT_FOUND)
600                 acpi_handle_warn(handle, "No _EJ0 support for device\n");
601         else if (ACPI_FAILURE(status))
602                 acpi_handle_warn(handle, "Eject failed (0x%x)\n", status);
603
604         return status;
605 }
606
607 /**
608  * acpi_evaluate_lck: Evaluate _LCK method to lock/unlock device
609  * @handle: ACPI device handle
610  * @lock: lock device if non-zero, otherwise unlock device
611  *
612  * Evaluate device's _LCK method if present to lock/unlock device
613  */
614 acpi_status acpi_evaluate_lck(acpi_handle handle, int lock)
615 {
616         acpi_status status;
617
618         status = acpi_execute_simple_method(handle, "_LCK", !!lock);
619         if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {
620                 if (lock)
621                         acpi_handle_warn(handle,
622                                 "Locking device failed (0x%x)\n", status);
623                 else
624                         acpi_handle_warn(handle,
625                                 "Unlocking device failed (0x%x)\n", status);
626         }
627
628         return status;
629 }
630
631 /**
632  * acpi_evaluate_dsm - evaluate device's _DSM method
633  * @handle: ACPI device handle
634  * @uuid: UUID of requested functions, should be 16 bytes
635  * @rev: revision number of requested function
636  * @func: requested function number
637  * @argv4: the function specific parameter
638  *
639  * Evaluate device's _DSM method with specified UUID, revision id and
640  * function number. Caller needs to free the returned object.
641  *
642  * Though ACPI defines the fourth parameter for _DSM should be a package,
643  * some old BIOSes do expect a buffer or an integer etc.
644  */
645 union acpi_object *
646 acpi_evaluate_dsm(acpi_handle handle, const u8 *uuid, int rev, int func,
647                   union acpi_object *argv4)
648 {
649         acpi_status ret;
650         struct acpi_buffer buf = {ACPI_ALLOCATE_BUFFER, NULL};
651         union acpi_object params[4];
652         struct acpi_object_list input = {
653                 .count = 4,
654                 .pointer = params,
655         };
656
657         params[0].type = ACPI_TYPE_BUFFER;
658         params[0].buffer.length = 16;
659         params[0].buffer.pointer = (char *)uuid;
660         params[1].type = ACPI_TYPE_INTEGER;
661         params[1].integer.value = rev;
662         params[2].type = ACPI_TYPE_INTEGER;
663         params[2].integer.value = func;
664         if (argv4) {
665                 params[3] = *argv4;
666         } else {
667                 params[3].type = ACPI_TYPE_PACKAGE;
668                 params[3].package.count = 0;
669                 params[3].package.elements = NULL;
670         }
671
672         ret = acpi_evaluate_object(handle, "_DSM", &input, &buf);
673         if (ACPI_SUCCESS(ret))
674                 return (union acpi_object *)buf.pointer;
675
676         if (ret != AE_NOT_FOUND)
677                 acpi_handle_warn(handle,
678                                 "failed to evaluate _DSM (0x%x)\n", ret);
679
680         return NULL;
681 }
682 EXPORT_SYMBOL(acpi_evaluate_dsm);
683
684 /**
685  * acpi_check_dsm - check if _DSM method supports requested functions.
686  * @handle: ACPI device handle
687  * @uuid: UUID of requested functions, should be 16 bytes at least
688  * @rev: revision number of requested functions
689  * @funcs: bitmap of requested functions
690  *
691  * Evaluate device's _DSM method to check whether it supports requested
692  * functions. Currently only support 64 functions at maximum, should be
693  * enough for now.
694  */
695 bool acpi_check_dsm(acpi_handle handle, const u8 *uuid, int rev, u64 funcs)
696 {
697         int i;
698         u64 mask = 0;
699         union acpi_object *obj;
700
701         if (funcs == 0)
702                 return false;
703
704         obj = acpi_evaluate_dsm(handle, uuid, rev, 0, NULL);
705         if (!obj)
706                 return false;
707
708         /* For compatibility, old BIOSes may return an integer */
709         if (obj->type == ACPI_TYPE_INTEGER)
710                 mask = obj->integer.value;
711         else if (obj->type == ACPI_TYPE_BUFFER)
712                 for (i = 0; i < obj->buffer.length && i < 8; i++)
713                         mask |= (((u8)obj->buffer.pointer[i]) << (i * 8));
714         ACPI_FREE(obj);
715
716         /*
717          * Bit 0 indicates whether there's support for any functions other than
718          * function 0 for the specified UUID and revision.
719          */
720         if ((mask & 0x1) && (mask & funcs) == funcs)
721                 return true;
722
723         return false;
724 }
725 EXPORT_SYMBOL(acpi_check_dsm);