linux/drivers/acpi/utils.c
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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#define pr_fmt(fmt) "ACPI: utils: " fmt
  10
  11#include <linux/kernel.h>
  12#include <linux/module.h>
  13#include <linux/slab.h>
  14#include <linux/init.h>
  15#include <linux/types.h>
  16#include <linux/hardirq.h>
  17#include <linux/acpi.h>
  18#include <linux/dynamic_debug.h>
  19
  20#include "internal.h"
  21#include "sleep.h"
  22
  23/* --------------------------------------------------------------------------
  24                            Object Evaluation Helpers
  25   -------------------------------------------------------------------------- */
  26static void acpi_util_eval_error(acpi_handle h, acpi_string p, acpi_status s)
  27{
  28        acpi_handle_debug(h, "Evaluate [%s]: %s\n", p, acpi_format_exception(s));
  29}
  30
  31acpi_status
  32acpi_extract_package(union acpi_object *package,
  33                     struct acpi_buffer *format, struct acpi_buffer *buffer)
  34{
  35        u32 size_required = 0;
  36        u32 tail_offset = 0;
  37        char *format_string = NULL;
  38        u32 format_count = 0;
  39        u32 i = 0;
  40        u8 *head = NULL;
  41        u8 *tail = NULL;
  42
  43
  44        if (!package || (package->type != ACPI_TYPE_PACKAGE)
  45            || (package->package.count < 1)) {
  46                pr_debug("Invalid package argument\n");
  47                return AE_BAD_PARAMETER;
  48        }
  49
  50        if (!format || !format->pointer || (format->length < 1)) {
  51                pr_debug("Invalid format argument\n");
  52                return AE_BAD_PARAMETER;
  53        }
  54
  55        if (!buffer) {
  56                pr_debug("Invalid buffer argument\n");
  57                return AE_BAD_PARAMETER;
  58        }
  59
  60        format_count = (format->length / sizeof(char)) - 1;
  61        if (format_count > package->package.count) {
  62                pr_debug("Format specifies more objects [%d] than present [%d]\n",
  63                         format_count, package->package.count);
  64                return AE_BAD_DATA;
  65        }
  66
  67        format_string = format->pointer;
  68
  69        /*
  70         * Calculate size_required.
  71         */
  72        for (i = 0; i < format_count; i++) {
  73
  74                union acpi_object *element = &(package->package.elements[i]);
  75
  76                switch (element->type) {
  77
  78                case ACPI_TYPE_INTEGER:
  79                        switch (format_string[i]) {
  80                        case 'N':
  81                                size_required += sizeof(u64);
  82                                tail_offset += sizeof(u64);
  83                                break;
  84                        case 'S':
  85                                size_required +=
  86                                    sizeof(char *) + sizeof(u64) +
  87                                    sizeof(char);
  88                                tail_offset += sizeof(char *);
  89                                break;
  90                        default:
  91                                pr_debug("Invalid package element [%d]: got number, expected [%c]\n",
  92                                         i, format_string[i]);
  93                                return AE_BAD_DATA;
  94                        }
  95                        break;
  96
  97                case ACPI_TYPE_STRING:
  98                case ACPI_TYPE_BUFFER:
  99                        switch (format_string[i]) {
 100                        case 'S':
 101                                size_required +=
 102                                    sizeof(char *) +
 103                                    (element->string.length * sizeof(char)) +
 104                                    sizeof(char);
 105                                tail_offset += sizeof(char *);
 106                                break;
 107                        case 'B':
 108                                size_required +=
 109                                    sizeof(u8 *) + element->buffer.length;
 110                                tail_offset += sizeof(u8 *);
 111                                break;
 112                        default:
 113                                pr_debug("Invalid package element [%d] got string/buffer, expected [%c]\n",
 114                                         i, format_string[i]);
 115                                return AE_BAD_DATA;
 116                        }
 117                        break;
 118                case ACPI_TYPE_LOCAL_REFERENCE:
 119                        switch (format_string[i]) {
 120                        case 'R':
 121                                size_required += sizeof(void *);
 122                                tail_offset += sizeof(void *);
 123                                break;
 124                        default:
 125                                pr_debug("Invalid package element [%d] got reference, expected [%c]\n",
 126                                         i, format_string[i]);
 127                                return AE_BAD_DATA;
 128                        }
 129                        break;
 130
 131                case ACPI_TYPE_PACKAGE:
 132                default:
 133                        pr_debug("Unsupported element at index=%d\n", i);
 134                        /* TBD: handle nested packages... */
 135                        return AE_SUPPORT;
 136                }
 137        }
 138
 139        /*
 140         * Validate output buffer.
 141         */
 142        if (buffer->length == ACPI_ALLOCATE_BUFFER) {
 143                buffer->pointer = ACPI_ALLOCATE_ZEROED(size_required);
 144                if (!buffer->pointer)
 145                        return AE_NO_MEMORY;
 146                buffer->length = size_required;
 147        } else {
 148                if (buffer->length < size_required) {
 149                        buffer->length = size_required;
 150                        return AE_BUFFER_OVERFLOW;
 151                } else if (buffer->length != size_required ||
 152                           !buffer->pointer) {
 153                        return AE_BAD_PARAMETER;
 154                }
 155        }
 156
 157        head = buffer->pointer;
 158        tail = buffer->pointer + tail_offset;
 159
 160        /*
 161         * Extract package data.
 162         */
 163        for (i = 0; i < format_count; i++) {
 164
 165                u8 **pointer = NULL;
 166                union acpi_object *element = &(package->package.elements[i]);
 167
 168                switch (element->type) {
 169
 170                case ACPI_TYPE_INTEGER:
 171                        switch (format_string[i]) {
 172                        case 'N':
 173                                *((u64 *) head) =
 174                                    element->integer.value;
 175                                head += sizeof(u64);
 176                                break;
 177                        case 'S':
 178                                pointer = (u8 **) head;
 179                                *pointer = tail;
 180                                *((u64 *) tail) =
 181                                    element->integer.value;
 182                                head += sizeof(u64 *);
 183                                tail += sizeof(u64);
 184                                /* NULL terminate string */
 185                                *tail = (char)0;
 186                                tail += sizeof(char);
 187                                break;
 188                        default:
 189                                /* Should never get here */
 190                                break;
 191                        }
 192                        break;
 193
 194                case ACPI_TYPE_STRING:
 195                case ACPI_TYPE_BUFFER:
 196                        switch (format_string[i]) {
 197                        case 'S':
 198                                pointer = (u8 **) head;
 199                                *pointer = tail;
 200                                memcpy(tail, element->string.pointer,
 201                                       element->string.length);
 202                                head += sizeof(char *);
 203                                tail += element->string.length * sizeof(char);
 204                                /* NULL terminate string */
 205                                *tail = (char)0;
 206                                tail += sizeof(char);
 207                                break;
 208                        case 'B':
 209                                pointer = (u8 **) head;
 210                                *pointer = tail;
 211                                memcpy(tail, element->buffer.pointer,
 212                                       element->buffer.length);
 213                                head += sizeof(u8 *);
 214                                tail += element->buffer.length;
 215                                break;
 216                        default:
 217                                /* Should never get here */
 218                                break;
 219                        }
 220                        break;
 221                case ACPI_TYPE_LOCAL_REFERENCE:
 222                        switch (format_string[i]) {
 223                        case 'R':
 224                                *(void **)head =
 225                                    (void *)element->reference.handle;
 226                                head += sizeof(void *);
 227                                break;
 228                        default:
 229                                /* Should never get here */
 230                                break;
 231                        }
 232                        break;
 233                case ACPI_TYPE_PACKAGE:
 234                        /* TBD: handle nested packages... */
 235                default:
 236                        /* Should never get here */
 237                        break;
 238                }
 239        }
 240
 241        return AE_OK;
 242}
 243
 244EXPORT_SYMBOL(acpi_extract_package);
 245
 246acpi_status
 247acpi_evaluate_integer(acpi_handle handle,
 248                      acpi_string pathname,
 249                      struct acpi_object_list *arguments, unsigned long long *data)
 250{
 251        acpi_status status = AE_OK;
 252        union acpi_object element;
 253        struct acpi_buffer buffer = { 0, NULL };
 254
 255        if (!data)
 256                return AE_BAD_PARAMETER;
 257
 258        buffer.length = sizeof(union acpi_object);
 259        buffer.pointer = &element;
 260        status = acpi_evaluate_object(handle, pathname, arguments, &buffer);
 261        if (ACPI_FAILURE(status)) {
 262                acpi_util_eval_error(handle, pathname, status);
 263                return status;
 264        }
 265
 266        if (element.type != ACPI_TYPE_INTEGER) {
 267                acpi_util_eval_error(handle, pathname, AE_BAD_DATA);
 268                return AE_BAD_DATA;
 269        }
 270
 271        *data = element.integer.value;
 272
 273        acpi_handle_debug(handle, "Return value [%llu]\n", *data);
 274
 275        return AE_OK;
 276}
 277
 278EXPORT_SYMBOL(acpi_evaluate_integer);
 279
 280acpi_status
 281acpi_evaluate_reference(acpi_handle handle,
 282                        acpi_string pathname,
 283                        struct acpi_object_list *arguments,
 284                        struct acpi_handle_list *list)
 285{
 286        acpi_status status = AE_OK;
 287        union acpi_object *package = NULL;
 288        union acpi_object *element = NULL;
 289        struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
 290        u32 i = 0;
 291
 292
 293        if (!list) {
 294                return AE_BAD_PARAMETER;
 295        }
 296
 297        /* Evaluate object. */
 298
 299        status = acpi_evaluate_object(handle, pathname, arguments, &buffer);
 300        if (ACPI_FAILURE(status))
 301                goto end;
 302
 303        package = buffer.pointer;
 304
 305        if ((buffer.length == 0) || !package) {
 306                status = AE_BAD_DATA;
 307                acpi_util_eval_error(handle, pathname, status);
 308                goto end;
 309        }
 310        if (package->type != ACPI_TYPE_PACKAGE) {
 311                status = AE_BAD_DATA;
 312                acpi_util_eval_error(handle, pathname, status);
 313                goto end;
 314        }
 315        if (!package->package.count) {
 316                status = AE_BAD_DATA;
 317                acpi_util_eval_error(handle, pathname, status);
 318                goto end;
 319        }
 320
 321        if (package->package.count > ACPI_MAX_HANDLES) {
 322                kfree(package);
 323                return AE_NO_MEMORY;
 324        }
 325        list->count = package->package.count;
 326
 327        /* Extract package data. */
 328
 329        for (i = 0; i < list->count; i++) {
 330
 331                element = &(package->package.elements[i]);
 332
 333                if (element->type != ACPI_TYPE_LOCAL_REFERENCE) {
 334                        status = AE_BAD_DATA;
 335                        acpi_util_eval_error(handle, pathname, status);
 336                        break;
 337                }
 338
 339                if (!element->reference.handle) {
 340                        status = AE_NULL_ENTRY;
 341                        acpi_util_eval_error(handle, pathname, status);
 342                        break;
 343                }
 344                /* Get the  acpi_handle. */
 345
 346                list->handles[i] = element->reference.handle;
 347                acpi_handle_debug(list->handles[i], "Found in reference list\n");
 348        }
 349
 350      end:
 351        if (ACPI_FAILURE(status)) {
 352                list->count = 0;
 353                //kfree(list->handles);
 354        }
 355
 356        kfree(buffer.pointer);
 357
 358        return status;
 359}
 360
 361EXPORT_SYMBOL(acpi_evaluate_reference);
 362
 363acpi_status
 364acpi_get_physical_device_location(acpi_handle handle, struct acpi_pld_info **pld)
 365{
 366        acpi_status status;
 367        struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
 368        union acpi_object *output;
 369
 370        status = acpi_evaluate_object(handle, "_PLD", NULL, &buffer);
 371
 372        if (ACPI_FAILURE(status))
 373                return status;
 374
 375        output = buffer.pointer;
 376
 377        if (!output || output->type != ACPI_TYPE_PACKAGE
 378            || !output->package.count
 379            || output->package.elements[0].type != ACPI_TYPE_BUFFER
 380            || output->package.elements[0].buffer.length < ACPI_PLD_REV1_BUFFER_SIZE) {
 381                status = AE_TYPE;
 382                goto out;
 383        }
 384
 385        status = acpi_decode_pld_buffer(
 386                        output->package.elements[0].buffer.pointer,
 387                        output->package.elements[0].buffer.length,
 388                        pld);
 389
 390out:
 391        kfree(buffer.pointer);
 392        return status;
 393}
 394EXPORT_SYMBOL(acpi_get_physical_device_location);
 395
 396/**
 397 * acpi_evaluate_ost: Evaluate _OST for hotplug operations
 398 * @handle: ACPI device handle
 399 * @source_event: source event code
 400 * @status_code: status code
 401 * @status_buf: optional detailed information (NULL if none)
 402 *
 403 * Evaluate _OST for hotplug operations. All ACPI hotplug handlers
 404 * must call this function when evaluating _OST for hotplug operations.
 405 * When the platform does not support _OST, this function has no effect.
 406 */
 407acpi_status
 408acpi_evaluate_ost(acpi_handle handle, u32 source_event, u32 status_code,
 409                  struct acpi_buffer *status_buf)
 410{
 411        union acpi_object params[3] = {
 412                {.type = ACPI_TYPE_INTEGER,},
 413                {.type = ACPI_TYPE_INTEGER,},
 414                {.type = ACPI_TYPE_BUFFER,}
 415        };
 416        struct acpi_object_list arg_list = {3, params};
 417
 418        params[0].integer.value = source_event;
 419        params[1].integer.value = status_code;
 420        if (status_buf != NULL) {
 421                params[2].buffer.pointer = status_buf->pointer;
 422                params[2].buffer.length = status_buf->length;
 423        } else {
 424                params[2].buffer.pointer = NULL;
 425                params[2].buffer.length = 0;
 426        }
 427
 428        return acpi_evaluate_object(handle, "_OST", &arg_list, NULL);
 429}
 430EXPORT_SYMBOL(acpi_evaluate_ost);
 431
 432/**
 433 * acpi_handle_path: Return the object path of handle
 434 * @handle: ACPI device handle
 435 *
 436 * Caller must free the returned buffer
 437 */
 438static char *acpi_handle_path(acpi_handle handle)
 439{
 440        struct acpi_buffer buffer = {
 441                .length = ACPI_ALLOCATE_BUFFER,
 442                .pointer = NULL
 443        };
 444
 445        if (in_interrupt() ||
 446            acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer) != AE_OK)
 447                return NULL;
 448        return buffer.pointer;
 449}
 450
 451/**
 452 * acpi_handle_printk: Print message with ACPI prefix and object path
 453 * @level: log level
 454 * @handle: ACPI device handle
 455 * @fmt: format string
 456 *
 457 * This function is called through acpi_handle_<level> macros and prints
 458 * a message with ACPI prefix and object path.  This function acquires
 459 * the global namespace mutex to obtain an object path.  In interrupt
 460 * context, it shows the object path as <n/a>.
 461 */
 462void
 463acpi_handle_printk(const char *level, acpi_handle handle, const char *fmt, ...)
 464{
 465        struct va_format vaf;
 466        va_list args;
 467        const char *path;
 468
 469        va_start(args, fmt);
 470        vaf.fmt = fmt;
 471        vaf.va = &args;
 472
 473        path = acpi_handle_path(handle);
 474        printk("%sACPI: %s: %pV", level, path ? path : "<n/a>" , &vaf);
 475
 476        va_end(args);
 477        kfree(path);
 478}
 479EXPORT_SYMBOL(acpi_handle_printk);
 480
 481#if defined(CONFIG_DYNAMIC_DEBUG)
 482/**
 483 * __acpi_handle_debug: pr_debug with ACPI prefix and object path
 484 * @descriptor: Dynamic Debug descriptor
 485 * @handle: ACPI device handle
 486 * @fmt: format string
 487 *
 488 * This function is called through acpi_handle_debug macro and debug
 489 * prints a message with ACPI prefix and object path. This function
 490 * acquires the global namespace mutex to obtain an object path.  In
 491 * interrupt context, it shows the object path as <n/a>.
 492 */
 493void
 494__acpi_handle_debug(struct _ddebug *descriptor, acpi_handle handle,
 495                    const char *fmt, ...)
 496{
 497        struct va_format vaf;
 498        va_list args;
 499        const char *path;
 500
 501        va_start(args, fmt);
 502        vaf.fmt = fmt;
 503        vaf.va = &args;
 504
 505        path = acpi_handle_path(handle);
 506        __dynamic_pr_debug(descriptor, "ACPI: %s: %pV", path ? path : "<n/a>", &vaf);
 507
 508        va_end(args);
 509        kfree(path);
 510}
 511EXPORT_SYMBOL(__acpi_handle_debug);
 512#endif
 513
 514/**
 515 * acpi_evaluation_failure_warn - Log evaluation failure warning.
 516 * @handle: Parent object handle.
 517 * @name: Name of the object whose evaluation has failed.
 518 * @status: Status value returned by the failing object evaluation.
 519 */
 520void acpi_evaluation_failure_warn(acpi_handle handle, const char *name,
 521                                  acpi_status status)
 522{
 523        acpi_handle_warn(handle, "%s evaluation failed: %s\n", name,
 524                         acpi_format_exception(status));
 525}
 526EXPORT_SYMBOL_GPL(acpi_evaluation_failure_warn);
 527
 528/**
 529 * acpi_has_method: Check whether @handle has a method named @name
 530 * @handle: ACPI device handle
 531 * @name: name of object or method
 532 *
 533 * Check whether @handle has a method named @name.
 534 */
 535bool acpi_has_method(acpi_handle handle, char *name)
 536{
 537        acpi_handle tmp;
 538
 539        return ACPI_SUCCESS(acpi_get_handle(handle, name, &tmp));
 540}
 541EXPORT_SYMBOL(acpi_has_method);
 542
 543acpi_status acpi_execute_simple_method(acpi_handle handle, char *method,
 544                                       u64 arg)
 545{
 546        union acpi_object obj = { .type = ACPI_TYPE_INTEGER };
 547        struct acpi_object_list arg_list = { .count = 1, .pointer = &obj, };
 548
 549        obj.integer.value = arg;
 550
 551        return acpi_evaluate_object(handle, method, &arg_list, NULL);
 552}
 553EXPORT_SYMBOL(acpi_execute_simple_method);
 554
 555/**
 556 * acpi_evaluate_ej0: Evaluate _EJ0 method for hotplug operations
 557 * @handle: ACPI device handle
 558 *
 559 * Evaluate device's _EJ0 method for hotplug operations.
 560 */
 561acpi_status acpi_evaluate_ej0(acpi_handle handle)
 562{
 563        acpi_status status;
 564
 565        status = acpi_execute_simple_method(handle, "_EJ0", 1);
 566        if (status == AE_NOT_FOUND)
 567                acpi_handle_warn(handle, "No _EJ0 support for device\n");
 568        else if (ACPI_FAILURE(status))
 569                acpi_handle_warn(handle, "Eject failed (0x%x)\n", status);
 570
 571        return status;
 572}
 573
 574/**
 575 * acpi_evaluate_lck: Evaluate _LCK method to lock/unlock device
 576 * @handle: ACPI device handle
 577 * @lock: lock device if non-zero, otherwise unlock device
 578 *
 579 * Evaluate device's _LCK method if present to lock/unlock device
 580 */
 581acpi_status acpi_evaluate_lck(acpi_handle handle, int lock)
 582{
 583        acpi_status status;
 584
 585        status = acpi_execute_simple_method(handle, "_LCK", !!lock);
 586        if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {
 587                if (lock)
 588                        acpi_handle_warn(handle,
 589                                "Locking device failed (0x%x)\n", status);
 590                else
 591                        acpi_handle_warn(handle,
 592                                "Unlocking device failed (0x%x)\n", status);
 593        }
 594
 595        return status;
 596}
 597
 598/**
 599 * acpi_evaluate_reg: Evaluate _REG method to register OpRegion presence
 600 * @handle: ACPI device handle
 601 * @space_id: ACPI address space id to register OpRegion presence for
 602 * @function: Parameter to pass to _REG one of ACPI_REG_CONNECT or
 603 *            ACPI_REG_DISCONNECT
 604 *
 605 * Evaluate device's _REG method to register OpRegion presence.
 606 */
 607acpi_status acpi_evaluate_reg(acpi_handle handle, u8 space_id, u32 function)
 608{
 609        struct acpi_object_list arg_list;
 610        union acpi_object params[2];
 611
 612        params[0].type = ACPI_TYPE_INTEGER;
 613        params[0].integer.value = space_id;
 614        params[1].type = ACPI_TYPE_INTEGER;
 615        params[1].integer.value = function;
 616        arg_list.count = 2;
 617        arg_list.pointer = params;
 618
 619        return acpi_evaluate_object(handle, "_REG", &arg_list, NULL);
 620}
 621EXPORT_SYMBOL(acpi_evaluate_reg);
 622
 623/**
 624 * acpi_evaluate_dsm - evaluate device's _DSM method
 625 * @handle: ACPI device handle
 626 * @guid: GUID of requested functions, should be 16 bytes
 627 * @rev: revision number of requested function
 628 * @func: requested function number
 629 * @argv4: the function specific parameter
 630 *
 631 * Evaluate device's _DSM method with specified GUID, revision id and
 632 * function number. Caller needs to free the returned object.
 633 *
 634 * Though ACPI defines the fourth parameter for _DSM should be a package,
 635 * some old BIOSes do expect a buffer or an integer etc.
 636 */
 637union acpi_object *
 638acpi_evaluate_dsm(acpi_handle handle, const guid_t *guid, u64 rev, u64 func,
 639                  union acpi_object *argv4)
 640{
 641        acpi_status ret;
 642        struct acpi_buffer buf = {ACPI_ALLOCATE_BUFFER, NULL};
 643        union acpi_object params[4];
 644        struct acpi_object_list input = {
 645                .count = 4,
 646                .pointer = params,
 647        };
 648
 649        params[0].type = ACPI_TYPE_BUFFER;
 650        params[0].buffer.length = 16;
 651        params[0].buffer.pointer = (u8 *)guid;
 652        params[1].type = ACPI_TYPE_INTEGER;
 653        params[1].integer.value = rev;
 654        params[2].type = ACPI_TYPE_INTEGER;
 655        params[2].integer.value = func;
 656        if (argv4) {
 657                params[3] = *argv4;
 658        } else {
 659                params[3].type = ACPI_TYPE_PACKAGE;
 660                params[3].package.count = 0;
 661                params[3].package.elements = NULL;
 662        }
 663
 664        ret = acpi_evaluate_object(handle, "_DSM", &input, &buf);
 665        if (ACPI_SUCCESS(ret))
 666                return (union acpi_object *)buf.pointer;
 667
 668        if (ret != AE_NOT_FOUND)
 669                acpi_handle_warn(handle,
 670                                "failed to evaluate _DSM (0x%x)\n", ret);
 671
 672        return NULL;
 673}
 674EXPORT_SYMBOL(acpi_evaluate_dsm);
 675
 676/**
 677 * acpi_check_dsm - check if _DSM method supports requested functions.
 678 * @handle: ACPI device handle
 679 * @guid: GUID of requested functions, should be 16 bytes at least
 680 * @rev: revision number of requested functions
 681 * @funcs: bitmap of requested functions
 682 *
 683 * Evaluate device's _DSM method to check whether it supports requested
 684 * functions. Currently only support 64 functions at maximum, should be
 685 * enough for now.
 686 */
 687bool acpi_check_dsm(acpi_handle handle, const guid_t *guid, u64 rev, u64 funcs)
 688{
 689        int i;
 690        u64 mask = 0;
 691        union acpi_object *obj;
 692
 693        if (funcs == 0)
 694                return false;
 695
 696        obj = acpi_evaluate_dsm(handle, guid, rev, 0, NULL);
 697        if (!obj)
 698                return false;
 699
 700        /* For compatibility, old BIOSes may return an integer */
 701        if (obj->type == ACPI_TYPE_INTEGER)
 702                mask = obj->integer.value;
 703        else if (obj->type == ACPI_TYPE_BUFFER)
 704                for (i = 0; i < obj->buffer.length && i < 8; i++)
 705                        mask |= (((u64)obj->buffer.pointer[i]) << (i * 8));
 706        ACPI_FREE(obj);
 707
 708        /*
 709         * Bit 0 indicates whether there's support for any functions other than
 710         * function 0 for the specified GUID and revision.
 711         */
 712        if ((mask & 0x1) && (mask & funcs) == funcs)
 713                return true;
 714
 715        return false;
 716}
 717EXPORT_SYMBOL(acpi_check_dsm);
 718
 719/**
 720 * acpi_dev_hid_uid_match - Match device by supplied HID and UID
 721 * @adev: ACPI device to match.
 722 * @hid2: Hardware ID of the device.
 723 * @uid2: Unique ID of the device, pass NULL to not check _UID.
 724 *
 725 * Matches HID and UID in @adev with given @hid2 and @uid2.
 726 * Returns true if matches.
 727 */
 728bool acpi_dev_hid_uid_match(struct acpi_device *adev,
 729                            const char *hid2, const char *uid2)
 730{
 731        const char *hid1 = acpi_device_hid(adev);
 732        const char *uid1 = acpi_device_uid(adev);
 733
 734        if (strcmp(hid1, hid2))
 735                return false;
 736
 737        if (!uid2)
 738                return true;
 739
 740        return uid1 && !strcmp(uid1, uid2);
 741}
 742EXPORT_SYMBOL(acpi_dev_hid_uid_match);
 743
 744/**
 745 * acpi_dev_found - Detect presence of a given ACPI device in the namespace.
 746 * @hid: Hardware ID of the device.
 747 *
 748 * Return %true if the device was present at the moment of invocation.
 749 * Note that if the device is pluggable, it may since have disappeared.
 750 *
 751 * For this function to work, acpi_bus_scan() must have been executed
 752 * which happens in the subsys_initcall() subsection. Hence, do not
 753 * call from a subsys_initcall() or earlier (use acpi_get_devices()
 754 * instead). Calling from module_init() is fine (which is synonymous
 755 * with device_initcall()).
 756 */
 757bool acpi_dev_found(const char *hid)
 758{
 759        struct acpi_device_bus_id *acpi_device_bus_id;
 760        bool found = false;
 761
 762        mutex_lock(&acpi_device_lock);
 763        list_for_each_entry(acpi_device_bus_id, &acpi_bus_id_list, node)
 764                if (!strcmp(acpi_device_bus_id->bus_id, hid)) {
 765                        found = true;
 766                        break;
 767                }
 768        mutex_unlock(&acpi_device_lock);
 769
 770        return found;
 771}
 772EXPORT_SYMBOL(acpi_dev_found);
 773
 774struct acpi_dev_match_info {
 775        struct acpi_device_id hid[2];
 776        const char *uid;
 777        s64 hrv;
 778};
 779
 780static int acpi_dev_match_cb(struct device *dev, const void *data)
 781{
 782        struct acpi_device *adev = to_acpi_device(dev);
 783        const struct acpi_dev_match_info *match = data;
 784        unsigned long long hrv;
 785        acpi_status status;
 786
 787        if (acpi_match_device_ids(adev, match->hid))
 788                return 0;
 789
 790        if (match->uid && (!adev->pnp.unique_id ||
 791            strcmp(adev->pnp.unique_id, match->uid)))
 792                return 0;
 793
 794        if (match->hrv == -1)
 795                return 1;
 796
 797        status = acpi_evaluate_integer(adev->handle, "_HRV", NULL, &hrv);
 798        if (ACPI_FAILURE(status))
 799                return 0;
 800
 801        return hrv == match->hrv;
 802}
 803
 804/**
 805 * acpi_dev_present - Detect that a given ACPI device is present
 806 * @hid: Hardware ID of the device.
 807 * @uid: Unique ID of the device, pass NULL to not check _UID
 808 * @hrv: Hardware Revision of the device, pass -1 to not check _HRV
 809 *
 810 * Return %true if a matching device was present at the moment of invocation.
 811 * Note that if the device is pluggable, it may since have disappeared.
 812 *
 813 * Note that unlike acpi_dev_found() this function checks the status
 814 * of the device. So for devices which are present in the DSDT, but
 815 * which are disabled (their _STA callback returns 0) this function
 816 * will return false.
 817 *
 818 * For this function to work, acpi_bus_scan() must have been executed
 819 * which happens in the subsys_initcall() subsection. Hence, do not
 820 * call from a subsys_initcall() or earlier (use acpi_get_devices()
 821 * instead). Calling from module_init() is fine (which is synonymous
 822 * with device_initcall()).
 823 */
 824bool acpi_dev_present(const char *hid, const char *uid, s64 hrv)
 825{
 826        struct acpi_dev_match_info match = {};
 827        struct device *dev;
 828
 829        strlcpy(match.hid[0].id, hid, sizeof(match.hid[0].id));
 830        match.uid = uid;
 831        match.hrv = hrv;
 832
 833        dev = bus_find_device(&acpi_bus_type, NULL, &match, acpi_dev_match_cb);
 834        put_device(dev);
 835        return !!dev;
 836}
 837EXPORT_SYMBOL(acpi_dev_present);
 838
 839/**
 840 * acpi_dev_get_next_match_dev - Return the next match of ACPI device
 841 * @adev: Pointer to the previous ACPI device matching this @hid, @uid and @hrv
 842 * @hid: Hardware ID of the device.
 843 * @uid: Unique ID of the device, pass NULL to not check _UID
 844 * @hrv: Hardware Revision of the device, pass -1 to not check _HRV
 845 *
 846 * Return the next match of ACPI device if another matching device was present
 847 * at the moment of invocation, or NULL otherwise.
 848 *
 849 * The caller is responsible for invoking acpi_dev_put() on the returned device.
 850 * On the other hand the function invokes  acpi_dev_put() on the given @adev
 851 * assuming that its reference counter had been increased beforehand.
 852 *
 853 * See additional information in acpi_dev_present() as well.
 854 */
 855struct acpi_device *
 856acpi_dev_get_next_match_dev(struct acpi_device *adev, const char *hid, const char *uid, s64 hrv)
 857{
 858        struct device *start = adev ? &adev->dev : NULL;
 859        struct acpi_dev_match_info match = {};
 860        struct device *dev;
 861
 862        strlcpy(match.hid[0].id, hid, sizeof(match.hid[0].id));
 863        match.uid = uid;
 864        match.hrv = hrv;
 865
 866        dev = bus_find_device(&acpi_bus_type, start, &match, acpi_dev_match_cb);
 867        acpi_dev_put(adev);
 868        return dev ? to_acpi_device(dev) : NULL;
 869}
 870EXPORT_SYMBOL(acpi_dev_get_next_match_dev);
 871
 872/**
 873 * acpi_dev_get_first_match_dev - Return the first match of ACPI device
 874 * @hid: Hardware ID of the device.
 875 * @uid: Unique ID of the device, pass NULL to not check _UID
 876 * @hrv: Hardware Revision of the device, pass -1 to not check _HRV
 877 *
 878 * Return the first match of ACPI device if a matching device was present
 879 * at the moment of invocation, or NULL otherwise.
 880 *
 881 * The caller is responsible for invoking acpi_dev_put() on the returned device.
 882 *
 883 * See additional information in acpi_dev_present() as well.
 884 */
 885struct acpi_device *
 886acpi_dev_get_first_match_dev(const char *hid, const char *uid, s64 hrv)
 887{
 888        return acpi_dev_get_next_match_dev(NULL, hid, uid, hrv);
 889}
 890EXPORT_SYMBOL(acpi_dev_get_first_match_dev);
 891
 892/**
 893 * acpi_reduced_hardware - Return if this is an ACPI-reduced-hw machine
 894 *
 895 * Return true when running on an ACPI-reduced-hw machine, false otherwise.
 896 */
 897bool acpi_reduced_hardware(void)
 898{
 899        return acpi_gbl_reduced_hardware;
 900}
 901EXPORT_SYMBOL_GPL(acpi_reduced_hardware);
 902
 903/*
 904 * acpi_backlight= handling, this is done here rather then in video_detect.c
 905 * because __setup cannot be used in modules.
 906 */
 907char acpi_video_backlight_string[16];
 908EXPORT_SYMBOL(acpi_video_backlight_string);
 909
 910static int __init acpi_backlight(char *str)
 911{
 912        strlcpy(acpi_video_backlight_string, str,
 913                sizeof(acpi_video_backlight_string));
 914        return 1;
 915}
 916__setup("acpi_backlight=", acpi_backlight);
 917
 918/**
 919 * acpi_match_platform_list - Check if the system matches with a given list
 920 * @plat: pointer to acpi_platform_list table terminated by a NULL entry
 921 *
 922 * Return the matched index if the system is found in the platform list.
 923 * Otherwise, return a negative error code.
 924 */
 925int acpi_match_platform_list(const struct acpi_platform_list *plat)
 926{
 927        struct acpi_table_header hdr;
 928        int idx = 0;
 929
 930        if (acpi_disabled)
 931                return -ENODEV;
 932
 933        for (; plat->oem_id[0]; plat++, idx++) {
 934                if (ACPI_FAILURE(acpi_get_table_header(plat->table, 0, &hdr)))
 935                        continue;
 936
 937                if (strncmp(plat->oem_id, hdr.oem_id, ACPI_OEM_ID_SIZE))
 938                        continue;
 939
 940                if (strncmp(plat->oem_table_id, hdr.oem_table_id, ACPI_OEM_TABLE_ID_SIZE))
 941                        continue;
 942
 943                if ((plat->pred == all_versions) ||
 944                    (plat->pred == less_than_or_equal && hdr.oem_revision <= plat->oem_revision) ||
 945                    (plat->pred == greater_than_or_equal && hdr.oem_revision >= plat->oem_revision) ||
 946                    (plat->pred == equal && hdr.oem_revision == plat->oem_revision))
 947                        return idx;
 948        }
 949
 950        return -ENODEV;
 951}
 952EXPORT_SYMBOL(acpi_match_platform_list);
 953