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  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  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
  35 ACPI_MODULE_NAME("utils");
  36
  37 /* --------------------------------------------------------------------------
  38                             Object Evaluation Helpers
  39    -------------------------------------------------------------------------- */
  40 static void
  41 acpi_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
  54 acpi_status
  55 acpi_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
 280 EXPORT_SYMBOL(acpi_extract_package);
 281
 282 acpi_status
 283 acpi_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
 314 EXPORT_SYMBOL(acpi_evaluate_integer);
 315
 316 acpi_status
 317 acpi_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                 kfree(package);
 359                 return AE_NO_MEMORY;
 360         }
 361         list->count = package->package.count;
 362
 363         /* Extract package data. */
 364
 365         for (i = 0; i < list->count; i++) {
 366
 367                 element = &(package->package.elements[i]);
 368
 369                 if (element->type != ACPI_TYPE_LOCAL_REFERENCE) {
 370                         status = AE_BAD_DATA;
 371                         acpi_util_eval_error(handle, pathname, status);
 372                         break;
 373                 }
 374
 375                 if (!element->reference.handle) {
 376                         status = AE_NULL_ENTRY;
 377                         acpi_util_eval_error(handle, pathname, status);
 378                         break;
 379                 }
 380                 /* Get the  acpi_handle. */
 381
 382                 list->handles[i] = element->reference.handle;
 383                 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found reference [%p]\n",
 384                                   list->handles[i]));
 385         }
 386
 387       end:
 388         if (ACPI_FAILURE(status)) {
 389                 list->count = 0;
 390                 //kfree(list->handles);
 391         }
 392
 393         kfree(buffer.pointer);
 394
 395         return status;
 396 }
 397
 398 EXPORT_SYMBOL(acpi_evaluate_reference);
 399
 400 acpi_status
 401 acpi_get_physical_device_location(acpi_handle handle, struct acpi_pld_info **pld)
 402 {
 403         acpi_status status;
 404         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
 405         union acpi_object *output;
 406
 407         status = acpi_evaluate_object(handle, "_PLD", NULL, &buffer);
 408
 409         if (ACPI_FAILURE(status))
 410                 return status;
 411
 412         output = buffer.pointer;
 413
 414         if (!output || output->type != ACPI_TYPE_PACKAGE
 415             || !output->package.count
 416             || output->package.elements[0].type != ACPI_TYPE_BUFFER
 417             || output->package.elements[0].buffer.length < ACPI_PLD_REV1_BUFFER_SIZE) {
 418                 status = AE_TYPE;
 419                 goto out;
 420         }
 421
 422         status = acpi_decode_pld_buffer(
 423                         output->package.elements[0].buffer.pointer,
 424                         output->package.elements[0].buffer.length,
 425                         pld);
 426
 427 out:
 428         kfree(buffer.pointer);
 429         return status;
 430 }
 431 EXPORT_SYMBOL(acpi_get_physical_device_location);
 432
 433 /**
 434  * acpi_evaluate_ost: Evaluate _OST for hotplug operations
 435  * @handle: ACPI device handle
 436  * @source_event: source event code
 437  * @status_code: status code
 438  * @status_buf: optional detailed information (NULL if none)
 439  *
 440  * Evaluate _OST for hotplug operations. All ACPI hotplug handlers
 441  * must call this function when evaluating _OST for hotplug operations.
 442  * When the platform does not support _OST, this function has no effect.
 443  */
 444 acpi_status
 445 acpi_evaluate_ost(acpi_handle handle, u32 source_event, u32 status_code,
 446                   struct acpi_buffer *status_buf)
 447 {
 448         union acpi_object params[3] = {
 449                 {.type = ACPI_TYPE_INTEGER,},
 450                 {.type = ACPI_TYPE_INTEGER,},
 451                 {.type = ACPI_TYPE_BUFFER,}
 452         };
 453         struct acpi_object_list arg_list = {3, params};
 454
 455         params[0].integer.value = source_event;
 456         params[1].integer.value = status_code;
 457         if (status_buf != NULL) {
 458                 params[2].buffer.pointer = status_buf->pointer;
 459                 params[2].buffer.length = status_buf->length;
 460         } else {
 461                 params[2].buffer.pointer = NULL;
 462                 params[2].buffer.length = 0;
 463         }
 464
 465         return acpi_evaluate_object(handle, "_OST", &arg_list, NULL);
 466 }
 467 EXPORT_SYMBOL(acpi_evaluate_ost);
 468
 469 /**
 470  * acpi_handle_path: Return the object path of handle
 471  *
 472  * Caller must free the returned buffer
 473  */
 474 static char *acpi_handle_path(acpi_handle handle)
 475 {
 476         struct acpi_buffer buffer = {
 477                 .length = ACPI_ALLOCATE_BUFFER,
 478                 .pointer = NULL
 479         };
 480
 481         if (in_interrupt() ||
 482             acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer) != AE_OK)
 483                 return NULL;
 484         return buffer.pointer;
 485 }
 486
 487 /**
 488  * acpi_handle_printk: Print message with ACPI prefix and object path
 489  *
 490  * This function is called through acpi_handle_<level> macros and prints
 491  * a message with ACPI prefix and object path.  This function acquires
 492  * the global namespace mutex to obtain an object path.  In interrupt
 493  * context, it shows the object path as <n/a>.
 494  */
 495 void
 496 acpi_handle_printk(const char *level, acpi_handle handle, const char *fmt, ...)
 497 {
 498         struct va_format vaf;
 499         va_list args;
 500         const char *path;
 501
 502         va_start(args, fmt);
 503         vaf.fmt = fmt;
 504         vaf.va = &args;
 505
 506         path = acpi_handle_path(handle);
 507         printk("%sACPI: %s: %pV", level, path ? path : "<n/a>" , &vaf);
 508
 509         va_end(args);
 510         kfree(path);
 511 }
 512 EXPORT_SYMBOL(acpi_handle_printk);
 513
 514 #if defined(CONFIG_DYNAMIC_DEBUG)
 515 /**
 516  * __acpi_handle_debug: pr_debug with ACPI prefix and object path
 517  *
 518  * This function is called through acpi_handle_debug macro and debug
 519  * prints a message with ACPI prefix and object path. This function
 520  * acquires the global namespace mutex to obtain an object path.  In
 521  * interrupt context, it shows the object path as <n/a>.
 522  */
 523 void
 524 __acpi_handle_debug(struct _ddebug *descriptor, acpi_handle handle,
 525                     const char *fmt, ...)
 526 {
 527         struct va_format vaf;
 528         va_list args;
 529         const char *path;
 530
 531         va_start(args, fmt);
 532         vaf.fmt = fmt;
 533         vaf.va = &args;
 534
 535         path = acpi_handle_path(handle);
 536         __dynamic_pr_debug(descriptor, "ACPI: %s: %pV", path ? path : "<n/a>", &vaf);
 537
 538         va_end(args);
 539         kfree(path);
 540 }
 541 EXPORT_SYMBOL(__acpi_handle_debug);
 542 #endif
 543
 544 /**
 545  * acpi_has_method: Check whether @handle has a method named @name
 546  * @handle: ACPI device handle
 547  * @name: name of object or method
 548  *
 549  * Check whether @handle has a method named @name.
 550  */
 551 bool acpi_has_method(acpi_handle handle, char *name)
 552 {
 553         acpi_handle tmp;
 554
 555         return ACPI_SUCCESS(acpi_get_handle(handle, name, &tmp));
 556 }
 557 EXPORT_SYMBOL(acpi_has_method);
 558
 559 acpi_status acpi_execute_simple_method(acpi_handle handle, char *method,
 560                                        u64 arg)
 561 {
 562         union acpi_object obj = { .type = ACPI_TYPE_INTEGER };
 563         struct acpi_object_list arg_list = { .count = 1, .pointer = &obj, };
 564
 565         obj.integer.value = arg;
 566
 567         return acpi_evaluate_object(handle, method, &arg_list, NULL);
 568 }
 569 EXPORT_SYMBOL(acpi_execute_simple_method);
 570
 571 /**
 572  * acpi_evaluate_ej0: Evaluate _EJ0 method for hotplug operations
 573  * @handle: ACPI device handle
 574  *
 575  * Evaluate device's _EJ0 method for hotplug operations.
 576  */
 577 acpi_status acpi_evaluate_ej0(acpi_handle handle)
 578 {
 579         acpi_status status;
 580
 581         status = acpi_execute_simple_method(handle, "_EJ0", 1);
 582         if (status == AE_NOT_FOUND)
 583                 acpi_handle_warn(handle, "No _EJ0 support for device\n");
 584         else if (ACPI_FAILURE(status))
 585                 acpi_handle_warn(handle, "Eject failed (0x%x)\n", status);
 586
 587         return status;
 588 }
 589
 590 /**
 591  * acpi_evaluate_lck: Evaluate _LCK method to lock/unlock device
 592  * @handle: ACPI device handle
 593  * @lock: lock device if non-zero, otherwise unlock device
 594  *
 595  * Evaluate device's _LCK method if present to lock/unlock device
 596  */
 597 acpi_status acpi_evaluate_lck(acpi_handle handle, int lock)
 598 {
 599         acpi_status status;
 600
 601         status = acpi_execute_simple_method(handle, "_LCK", !!lock);
 602         if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {
 603                 if (lock)
 604                         acpi_handle_warn(handle,
 605                                 "Locking device failed (0x%x)\n", status);
 606                 else
 607                         acpi_handle_warn(handle,
 608                                 "Unlocking device failed (0x%x)\n", status);
 609         }
 610
 611         return status;
 612 }
 613
 614 /**
 615  * acpi_evaluate_dsm - evaluate device's _DSM method
 616  * @handle: ACPI device handle
 617  * @guid: GUID of requested functions, should be 16 bytes
 618  * @rev: revision number of requested function
 619  * @func: requested function number
 620  * @argv4: the function specific parameter
 621  *
 622  * Evaluate device's _DSM method with specified GUID, revision id and
 623  * function number. Caller needs to free the returned object.
 624  *
 625  * Though ACPI defines the fourth parameter for _DSM should be a package,
 626  * some old BIOSes do expect a buffer or an integer etc.
 627  */
 628 union acpi_object *
 629 acpi_evaluate_dsm(acpi_handle handle, const guid_t *guid, u64 rev, u64 func,
 630                   union acpi_object *argv4)
 631 {
 632         acpi_status ret;
 633         struct acpi_buffer buf = {ACPI_ALLOCATE_BUFFER, NULL};
 634         union acpi_object params[4];
 635         struct acpi_object_list input = {
 636                 .count = 4,
 637                 .pointer = params,
 638         };
 639
 640         params[0].type = ACPI_TYPE_BUFFER;
 641         params[0].buffer.length = 16;
 642         params[0].buffer.pointer = (u8 *)guid;
 643         params[1].type = ACPI_TYPE_INTEGER;
 644         params[1].integer.value = rev;
 645         params[2].type = ACPI_TYPE_INTEGER;
 646         params[2].integer.value = func;
 647         if (argv4) {
 648                 params[3] = *argv4;
 649         } else {
 650                 params[3].type = ACPI_TYPE_PACKAGE;
 651                 params[3].package.count = 0;
 652                 params[3].package.elements = NULL;
 653         }
 654
 655         ret = acpi_evaluate_object(handle, "_DSM", &input, &buf);
 656         if (ACPI_SUCCESS(ret))
 657                 return (union acpi_object *)buf.pointer;
 658
 659         if (ret != AE_NOT_FOUND)
 660                 acpi_handle_warn(handle,
 661                                 "failed to evaluate _DSM (0x%x)\n", ret);
 662
 663         return NULL;
 664 }
 665 EXPORT_SYMBOL(acpi_evaluate_dsm);
 666
 667 /**
 668  * acpi_check_dsm - check if _DSM method supports requested functions.
 669  * @handle: ACPI device handle
 670  * @guid: GUID of requested functions, should be 16 bytes at least
 671  * @rev: revision number of requested functions
 672  * @funcs: bitmap of requested functions
 673  *
 674  * Evaluate device's _DSM method to check whether it supports requested
 675  * functions. Currently only support 64 functions at maximum, should be
 676  * enough for now.
 677  */
 678 bool acpi_check_dsm(acpi_handle handle, const guid_t *guid, u64 rev, u64 funcs)
 679 {
 680         int i;
 681         u64 mask = 0;
 682         union acpi_object *obj;
 683
 684         if (funcs == 0)
 685                 return false;
 686
 687         obj = acpi_evaluate_dsm(handle, guid, rev, 0, NULL);
 688         if (!obj)
 689                 return false;
 690
 691         /* For compatibility, old BIOSes may return an integer */
 692         if (obj->type == ACPI_TYPE_INTEGER)
 693                 mask = obj->integer.value;
 694         else if (obj->type == ACPI_TYPE_BUFFER)
 695                 for (i = 0; i < obj->buffer.length && i < 8; i++)
 696                         mask |= (((u64)obj->buffer.pointer[i]) << (i * 8));
 697         ACPI_FREE(obj);
 698
 699         /*
 700          * Bit 0 indicates whether there's support for any functions other than
 701          * function 0 for the specified GUID and revision.
 702          */
 703         if ((mask & 0x1) && (mask & funcs) == funcs)
 704                 return true;
 705
 706         return false;
 707 }
 708 EXPORT_SYMBOL(acpi_check_dsm);
 709
 710 /**
 711  * acpi_dev_found - Detect presence of a given ACPI device in the namespace.
 712  * @hid: Hardware ID of the device.
 713  *
 714  * Return %true if the device was present at the moment of invocation.
 715  * Note that if the device is pluggable, it may since have disappeared.
 716  *
 717  * For this function to work, acpi_bus_scan() must have been executed
 718  * which happens in the subsys_initcall() subsection. Hence, do not
 719  * call from a subsys_initcall() or earlier (use acpi_get_devices()
 720  * instead). Calling from module_init() is fine (which is synonymous
 721  * with device_initcall()).
 722  */
 723 bool acpi_dev_found(const char *hid)
 724 {
 725         struct acpi_device_bus_id *acpi_device_bus_id;
 726         bool found = false;
 727
 728         mutex_lock(&acpi_device_lock);
 729         list_for_each_entry(acpi_device_bus_id, &acpi_bus_id_list, node)
 730                 if (!strcmp(acpi_device_bus_id->bus_id, hid)) {
 731                         found = true;
 732                         break;
 733                 }
 734         mutex_unlock(&acpi_device_lock);
 735
 736         return found;
 737 }
 738 EXPORT_SYMBOL(acpi_dev_found);
 739
 740 struct acpi_dev_present_info {
 741         struct acpi_device_id hid[2];
 742         const char *uid;
 743         s64 hrv;
 744 };
 745
 746 static int acpi_dev_present_cb(struct device *dev, void *data)
 747 {
 748         struct acpi_device *adev = to_acpi_device(dev);
 749         struct acpi_dev_present_info *match = data;
 750         unsigned long long hrv;
 751         acpi_status status;
 752
 753         if (acpi_match_device_ids(adev, match->hid))
 754                 return 0;
 755
 756         if (match->uid && (!adev->pnp.unique_id ||
 757             strcmp(adev->pnp.unique_id, match->uid)))
 758                 return 0;
 759
 760         if (match->hrv == -1)
 761                 return 1;
 762
 763         status = acpi_evaluate_integer(adev->handle, "_HRV", NULL, &hrv);
 764         if (ACPI_FAILURE(status))
 765                 return 0;
 766
 767         return hrv == match->hrv;
 768 }
 769
 770 /**
 771  * acpi_dev_present - Detect that a given ACPI device is present
 772  * @hid: Hardware ID of the device.
 773  * @uid: Unique ID of the device, pass NULL to not check _UID
 774  * @hrv: Hardware Revision of the device, pass -1 to not check _HRV
 775  *
 776  * Return %true if a matching device was present at the moment of invocation.
 777  * Note that if the device is pluggable, it may since have disappeared.
 778  *
 779  * Note that unlike acpi_dev_found() this function checks the status
 780  * of the device. So for devices which are present in the dsdt, but
 781  * which are disabled (their _STA callback returns 0) this function
 782  * will return false.
 783  *
 784  * For this function to work, acpi_bus_scan() must have been executed
 785  * which happens in the subsys_initcall() subsection. Hence, do not
 786  * call from a subsys_initcall() or earlier (use acpi_get_devices()
 787  * instead). Calling from module_init() is fine (which is synonymous
 788  * with device_initcall()).
 789  */
 790 bool acpi_dev_present(const char *hid, const char *uid, s64 hrv)
 791 {
 792         struct acpi_dev_present_info match = {};
 793         struct device *dev;
 794
 795         strlcpy(match.hid[0].id, hid, sizeof(match.hid[0].id));
 796         match.uid = uid;
 797         match.hrv = hrv;
 798
 799         dev = bus_find_device(&acpi_bus_type, NULL, &match,
 800                               acpi_dev_present_cb);
 801
 802         return !!dev;
 803 }
 804 EXPORT_SYMBOL(acpi_dev_present);
 805
 806 /*
 807  * acpi_backlight= handling, this is done here rather then in video_detect.c
 808  * because __setup cannot be used in modules.
 809  */
 810 char acpi_video_backlight_string[16];
 811 EXPORT_SYMBOL(acpi_video_backlight_string);
 812
 813 static int __init acpi_backlight(char *str)
 814 {
 815         strlcpy(acpi_video_backlight_string, str,
 816                 sizeof(acpi_video_backlight_string));
 817         return 1;
 818 }
 819 __setup("acpi_backlight=", acpi_backlight);
 820
 821 /**
 822  * acpi_match_platform_list - Check if the system matches with a given list
 823  * @plat: pointer to acpi_platform_list table terminated by a NULL entry
 824  *
 825  * Return the matched index if the system is found in the platform list.
 826  * Otherwise, return a negative error code.
 827  */
 828 int acpi_match_platform_list(const struct acpi_platform_list *plat)
 829 {
 830         struct acpi_table_header hdr;
 831         int idx = 0;
 832
 833         if (acpi_disabled)
 834                 return -ENODEV;
 835
 836         for (; plat->oem_id[0]; plat++, idx++) {
 837                 if (ACPI_FAILURE(acpi_get_table_header(plat->table, 0, &hdr)))
 838                         continue;
 839
 840                 if (strncmp(plat->oem_id, hdr.oem_id, ACPI_OEM_ID_SIZE))
 841                         continue;
 842
 843                 if (strncmp(plat->oem_table_id, hdr.oem_table_id, ACPI_OEM_TABLE_ID_SIZE))
 844                         continue;
 845
 846                 if ((plat->pred == all_versions) ||
 847                     (plat->pred == less_than_or_equal && hdr.oem_revision <= plat->oem_revision) ||
 848                     (plat->pred == greater_than_or_equal && hdr.oem_revision >= plat->oem_revision) ||
 849                     (plat->pred == equal && hdr.oem_revision == plat->oem_revision))
 850                         return idx;
 851         }
 852
 853         return -ENODEV;
 854 }
 855 EXPORT_SYMBOL(acpi_match_platform_list);