linux/drivers/firmware/dmi_scan.c
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   1#include <linux/types.h>
   2#include <linux/string.h>
   3#include <linux/init.h>
   4#include <linux/module.h>
   5#include <linux/ctype.h>
   6#include <linux/dmi.h>
   7#include <linux/efi.h>
   8#include <linux/bootmem.h>
   9#include <asm/dmi.h>
  10
  11/*
  12 * DMI stands for "Desktop Management Interface".  It is part
  13 * of and an antecedent to, SMBIOS, which stands for System
  14 * Management BIOS.  See further: http://www.dmtf.org/standards
  15 */
  16static char dmi_empty_string[] = "        ";
  17
  18/*
  19 * Catch too early calls to dmi_check_system():
  20 */
  21static int dmi_initialized;
  22
  23static const char * __init dmi_string_nosave(const struct dmi_header *dm, u8 s)
  24{
  25        const u8 *bp = ((u8 *) dm) + dm->length;
  26
  27        if (s) {
  28                s--;
  29                while (s > 0 && *bp) {
  30                        bp += strlen(bp) + 1;
  31                        s--;
  32                }
  33
  34                if (*bp != 0) {
  35                        size_t len = strlen(bp)+1;
  36                        size_t cmp_len = len > 8 ? 8 : len;
  37
  38                        if (!memcmp(bp, dmi_empty_string, cmp_len))
  39                                return dmi_empty_string;
  40                        return bp;
  41                }
  42        }
  43
  44        return "";
  45}
  46
  47static char * __init dmi_string(const struct dmi_header *dm, u8 s)
  48{
  49        const char *bp = dmi_string_nosave(dm, s);
  50        char *str;
  51        size_t len;
  52
  53        if (bp == dmi_empty_string)
  54                return dmi_empty_string;
  55
  56        len = strlen(bp) + 1;
  57        str = dmi_alloc(len);
  58        if (str != NULL)
  59                strcpy(str, bp);
  60        else
  61                printk(KERN_ERR "dmi_string: cannot allocate %Zu bytes.\n", len);
  62
  63        return str;
  64}
  65
  66/*
  67 *      We have to be cautious here. We have seen BIOSes with DMI pointers
  68 *      pointing to completely the wrong place for example
  69 */
  70static void dmi_table(u8 *buf, int len, int num,
  71                      void (*decode)(const struct dmi_header *, void *),
  72                      void *private_data)
  73{
  74        u8 *data = buf;
  75        int i = 0;
  76
  77        /*
  78         *      Stop when we see all the items the table claimed to have
  79         *      OR we run off the end of the table (also happens)
  80         */
  81        while ((i < num) && (data - buf + sizeof(struct dmi_header)) <= len) {
  82                const struct dmi_header *dm = (const struct dmi_header *)data;
  83
  84                /*
  85                 *  We want to know the total length (formatted area and
  86                 *  strings) before decoding to make sure we won't run off the
  87                 *  table in dmi_decode or dmi_string
  88                 */
  89                data += dm->length;
  90                while ((data - buf < len - 1) && (data[0] || data[1]))
  91                        data++;
  92                if (data - buf < len - 1)
  93                        decode(dm, private_data);
  94                data += 2;
  95                i++;
  96        }
  97}
  98
  99static u32 dmi_base;
 100static u16 dmi_len;
 101static u16 dmi_num;
 102
 103static int __init dmi_walk_early(void (*decode)(const struct dmi_header *,
 104                void *))
 105{
 106        u8 *buf;
 107
 108        buf = dmi_ioremap(dmi_base, dmi_len);
 109        if (buf == NULL)
 110                return -1;
 111
 112        dmi_table(buf, dmi_len, dmi_num, decode, NULL);
 113
 114        dmi_iounmap(buf, dmi_len);
 115        return 0;
 116}
 117
 118static int __init dmi_checksum(const u8 *buf)
 119{
 120        u8 sum = 0;
 121        int a;
 122
 123        for (a = 0; a < 15; a++)
 124                sum += buf[a];
 125
 126        return sum == 0;
 127}
 128
 129static char *dmi_ident[DMI_STRING_MAX];
 130static LIST_HEAD(dmi_devices);
 131int dmi_available;
 132
 133/*
 134 *      Save a DMI string
 135 */
 136static void __init dmi_save_ident(const struct dmi_header *dm, int slot, int string)
 137{
 138        const char *d = (const char*) dm;
 139        char *p;
 140
 141        if (dmi_ident[slot])
 142                return;
 143
 144        p = dmi_string(dm, d[string]);
 145        if (p == NULL)
 146                return;
 147
 148        dmi_ident[slot] = p;
 149}
 150
 151static void __init dmi_save_uuid(const struct dmi_header *dm, int slot, int index)
 152{
 153        const u8 *d = (u8*) dm + index;
 154        char *s;
 155        int is_ff = 1, is_00 = 1, i;
 156
 157        if (dmi_ident[slot])
 158                return;
 159
 160        for (i = 0; i < 16 && (is_ff || is_00); i++) {
 161                if(d[i] != 0x00) is_ff = 0;
 162                if(d[i] != 0xFF) is_00 = 0;
 163        }
 164
 165        if (is_ff || is_00)
 166                return;
 167
 168        s = dmi_alloc(16*2+4+1);
 169        if (!s)
 170                return;
 171
 172        sprintf(s, "%pUB", d);
 173
 174        dmi_ident[slot] = s;
 175}
 176
 177static void __init dmi_save_type(const struct dmi_header *dm, int slot, int index)
 178{
 179        const u8 *d = (u8*) dm + index;
 180        char *s;
 181
 182        if (dmi_ident[slot])
 183                return;
 184
 185        s = dmi_alloc(4);
 186        if (!s)
 187                return;
 188
 189        sprintf(s, "%u", *d & 0x7F);
 190        dmi_ident[slot] = s;
 191}
 192
 193static void __init dmi_save_one_device(int type, const char *name)
 194{
 195        struct dmi_device *dev;
 196
 197        /* No duplicate device */
 198        if (dmi_find_device(type, name, NULL))
 199                return;
 200
 201        dev = dmi_alloc(sizeof(*dev) + strlen(name) + 1);
 202        if (!dev) {
 203                printk(KERN_ERR "dmi_save_one_device: out of memory.\n");
 204                return;
 205        }
 206
 207        dev->type = type;
 208        strcpy((char *)(dev + 1), name);
 209        dev->name = (char *)(dev + 1);
 210        dev->device_data = NULL;
 211        list_add(&dev->list, &dmi_devices);
 212}
 213
 214static void __init dmi_save_devices(const struct dmi_header *dm)
 215{
 216        int i, count = (dm->length - sizeof(struct dmi_header)) / 2;
 217
 218        for (i = 0; i < count; i++) {
 219                const char *d = (char *)(dm + 1) + (i * 2);
 220
 221                /* Skip disabled device */
 222                if ((*d & 0x80) == 0)
 223                        continue;
 224
 225                dmi_save_one_device(*d & 0x7f, dmi_string_nosave(dm, *(d + 1)));
 226        }
 227}
 228
 229static void __init dmi_save_oem_strings_devices(const struct dmi_header *dm)
 230{
 231        int i, count = *(u8 *)(dm + 1);
 232        struct dmi_device *dev;
 233
 234        for (i = 1; i <= count; i++) {
 235                char *devname = dmi_string(dm, i);
 236
 237                if (devname == dmi_empty_string)
 238                        continue;
 239
 240                dev = dmi_alloc(sizeof(*dev));
 241                if (!dev) {
 242                        printk(KERN_ERR
 243                           "dmi_save_oem_strings_devices: out of memory.\n");
 244                        break;
 245                }
 246
 247                dev->type = DMI_DEV_TYPE_OEM_STRING;
 248                dev->name = devname;
 249                dev->device_data = NULL;
 250
 251                list_add(&dev->list, &dmi_devices);
 252        }
 253}
 254
 255static void __init dmi_save_ipmi_device(const struct dmi_header *dm)
 256{
 257        struct dmi_device *dev;
 258        void * data;
 259
 260        data = dmi_alloc(dm->length);
 261        if (data == NULL) {
 262                printk(KERN_ERR "dmi_save_ipmi_device: out of memory.\n");
 263                return;
 264        }
 265
 266        memcpy(data, dm, dm->length);
 267
 268        dev = dmi_alloc(sizeof(*dev));
 269        if (!dev) {
 270                printk(KERN_ERR "dmi_save_ipmi_device: out of memory.\n");
 271                return;
 272        }
 273
 274        dev->type = DMI_DEV_TYPE_IPMI;
 275        dev->name = "IPMI controller";
 276        dev->device_data = data;
 277
 278        list_add_tail(&dev->list, &dmi_devices);
 279}
 280
 281static void __init dmi_save_dev_onboard(int instance, int segment, int bus,
 282                                        int devfn, const char *name)
 283{
 284        struct dmi_dev_onboard *onboard_dev;
 285
 286        onboard_dev = dmi_alloc(sizeof(*onboard_dev) + strlen(name) + 1);
 287        if (!onboard_dev) {
 288                printk(KERN_ERR "dmi_save_dev_onboard: out of memory.\n");
 289                return;
 290        }
 291        onboard_dev->instance = instance;
 292        onboard_dev->segment = segment;
 293        onboard_dev->bus = bus;
 294        onboard_dev->devfn = devfn;
 295
 296        strcpy((char *)&onboard_dev[1], name);
 297        onboard_dev->dev.type = DMI_DEV_TYPE_DEV_ONBOARD;
 298        onboard_dev->dev.name = (char *)&onboard_dev[1];
 299        onboard_dev->dev.device_data = onboard_dev;
 300
 301        list_add(&onboard_dev->dev.list, &dmi_devices);
 302}
 303
 304static void __init dmi_save_extended_devices(const struct dmi_header *dm)
 305{
 306        const u8 *d = (u8*) dm + 5;
 307
 308        /* Skip disabled device */
 309        if ((*d & 0x80) == 0)
 310                return;
 311
 312        dmi_save_dev_onboard(*(d+1), *(u16 *)(d+2), *(d+4), *(d+5),
 313                             dmi_string_nosave(dm, *(d-1)));
 314        dmi_save_one_device(*d & 0x7f, dmi_string_nosave(dm, *(d - 1)));
 315}
 316
 317/*
 318 *      Process a DMI table entry. Right now all we care about are the BIOS
 319 *      and machine entries. For 2.5 we should pull the smbus controller info
 320 *      out of here.
 321 */
 322static void __init dmi_decode(const struct dmi_header *dm, void *dummy)
 323{
 324        switch(dm->type) {
 325        case 0:         /* BIOS Information */
 326                dmi_save_ident(dm, DMI_BIOS_VENDOR, 4);
 327                dmi_save_ident(dm, DMI_BIOS_VERSION, 5);
 328                dmi_save_ident(dm, DMI_BIOS_DATE, 8);
 329                break;
 330        case 1:         /* System Information */
 331                dmi_save_ident(dm, DMI_SYS_VENDOR, 4);
 332                dmi_save_ident(dm, DMI_PRODUCT_NAME, 5);
 333                dmi_save_ident(dm, DMI_PRODUCT_VERSION, 6);
 334                dmi_save_ident(dm, DMI_PRODUCT_SERIAL, 7);
 335                dmi_save_uuid(dm, DMI_PRODUCT_UUID, 8);
 336                break;
 337        case 2:         /* Base Board Information */
 338                dmi_save_ident(dm, DMI_BOARD_VENDOR, 4);
 339                dmi_save_ident(dm, DMI_BOARD_NAME, 5);
 340                dmi_save_ident(dm, DMI_BOARD_VERSION, 6);
 341                dmi_save_ident(dm, DMI_BOARD_SERIAL, 7);
 342                dmi_save_ident(dm, DMI_BOARD_ASSET_TAG, 8);
 343                break;
 344        case 3:         /* Chassis Information */
 345                dmi_save_ident(dm, DMI_CHASSIS_VENDOR, 4);
 346                dmi_save_type(dm, DMI_CHASSIS_TYPE, 5);
 347                dmi_save_ident(dm, DMI_CHASSIS_VERSION, 6);
 348                dmi_save_ident(dm, DMI_CHASSIS_SERIAL, 7);
 349                dmi_save_ident(dm, DMI_CHASSIS_ASSET_TAG, 8);
 350                break;
 351        case 10:        /* Onboard Devices Information */
 352                dmi_save_devices(dm);
 353                break;
 354        case 11:        /* OEM Strings */
 355                dmi_save_oem_strings_devices(dm);
 356                break;
 357        case 38:        /* IPMI Device Information */
 358                dmi_save_ipmi_device(dm);
 359                break;
 360        case 41:        /* Onboard Devices Extended Information */
 361                dmi_save_extended_devices(dm);
 362        }
 363}
 364
 365static void __init print_filtered(const char *info)
 366{
 367        const char *p;
 368
 369        if (!info)
 370                return;
 371
 372        for (p = info; *p; p++)
 373                if (isprint(*p))
 374                        printk(KERN_CONT "%c", *p);
 375                else
 376                        printk(KERN_CONT "\\x%02x", *p & 0xff);
 377}
 378
 379static void __init dmi_dump_ids(void)
 380{
 381        printk(KERN_DEBUG "DMI: ");
 382        print_filtered(dmi_get_system_info(DMI_BOARD_NAME));
 383        printk(KERN_CONT "/");
 384        print_filtered(dmi_get_system_info(DMI_PRODUCT_NAME));
 385        printk(KERN_CONT ", BIOS ");
 386        print_filtered(dmi_get_system_info(DMI_BIOS_VERSION));
 387        printk(KERN_CONT " ");
 388        print_filtered(dmi_get_system_info(DMI_BIOS_DATE));
 389        printk(KERN_CONT "\n");
 390}
 391
 392static int __init dmi_present(const char __iomem *p)
 393{
 394        u8 buf[15];
 395
 396        memcpy_fromio(buf, p, 15);
 397        if ((memcmp(buf, "_DMI_", 5) == 0) && dmi_checksum(buf)) {
 398                dmi_num = (buf[13] << 8) | buf[12];
 399                dmi_len = (buf[7] << 8) | buf[6];
 400                dmi_base = (buf[11] << 24) | (buf[10] << 16) |
 401                        (buf[9] << 8) | buf[8];
 402
 403                /*
 404                 * DMI version 0.0 means that the real version is taken from
 405                 * the SMBIOS version, which we don't know at this point.
 406                 */
 407                if (buf[14] != 0)
 408                        printk(KERN_INFO "DMI %d.%d present.\n",
 409                               buf[14] >> 4, buf[14] & 0xF);
 410                else
 411                        printk(KERN_INFO "DMI present.\n");
 412                if (dmi_walk_early(dmi_decode) == 0) {
 413                        dmi_dump_ids();
 414                        return 0;
 415                }
 416        }
 417        return 1;
 418}
 419
 420void __init dmi_scan_machine(void)
 421{
 422        char __iomem *p, *q;
 423        int rc;
 424
 425        if (efi_enabled) {
 426                if (efi.smbios == EFI_INVALID_TABLE_ADDR)
 427                        goto error;
 428
 429                /* This is called as a core_initcall() because it isn't
 430                 * needed during early boot.  This also means we can
 431                 * iounmap the space when we're done with it.
 432                 */
 433                p = dmi_ioremap(efi.smbios, 32);
 434                if (p == NULL)
 435                        goto error;
 436
 437                rc = dmi_present(p + 0x10); /* offset of _DMI_ string */
 438                dmi_iounmap(p, 32);
 439                if (!rc) {
 440                        dmi_available = 1;
 441                        goto out;
 442                }
 443        }
 444        else {
 445                /*
 446                 * no iounmap() for that ioremap(); it would be a no-op, but
 447                 * it's so early in setup that sucker gets confused into doing
 448                 * what it shouldn't if we actually call it.
 449                 */
 450                p = dmi_ioremap(0xF0000, 0x10000);
 451                if (p == NULL)
 452                        goto error;
 453
 454                for (q = p; q < p + 0x10000; q += 16) {
 455                        rc = dmi_present(q);
 456                        if (!rc) {
 457                                dmi_available = 1;
 458                                dmi_iounmap(p, 0x10000);
 459                                goto out;
 460                        }
 461                }
 462                dmi_iounmap(p, 0x10000);
 463        }
 464 error:
 465        printk(KERN_INFO "DMI not present or invalid.\n");
 466 out:
 467        dmi_initialized = 1;
 468}
 469
 470/**
 471 *      dmi_matches - check if dmi_system_id structure matches system DMI data
 472 *      @dmi: pointer to the dmi_system_id structure to check
 473 */
 474static bool dmi_matches(const struct dmi_system_id *dmi)
 475{
 476        int i;
 477
 478        WARN(!dmi_initialized, KERN_ERR "dmi check: not initialized yet.\n");
 479
 480        for (i = 0; i < ARRAY_SIZE(dmi->matches); i++) {
 481                int s = dmi->matches[i].slot;
 482                if (s == DMI_NONE)
 483                        break;
 484                if (dmi_ident[s]
 485                    && strstr(dmi_ident[s], dmi->matches[i].substr))
 486                        continue;
 487                /* No match */
 488                return false;
 489        }
 490        return true;
 491}
 492
 493/**
 494 *      dmi_is_end_of_table - check for end-of-table marker
 495 *      @dmi: pointer to the dmi_system_id structure to check
 496 */
 497static bool dmi_is_end_of_table(const struct dmi_system_id *dmi)
 498{
 499        return dmi->matches[0].slot == DMI_NONE;
 500}
 501
 502/**
 503 *      dmi_check_system - check system DMI data
 504 *      @list: array of dmi_system_id structures to match against
 505 *              All non-null elements of the list must match
 506 *              their slot's (field index's) data (i.e., each
 507 *              list string must be a substring of the specified
 508 *              DMI slot's string data) to be considered a
 509 *              successful match.
 510 *
 511 *      Walk the blacklist table running matching functions until someone
 512 *      returns non zero or we hit the end. Callback function is called for
 513 *      each successful match. Returns the number of matches.
 514 */
 515int dmi_check_system(const struct dmi_system_id *list)
 516{
 517        int count = 0;
 518        const struct dmi_system_id *d;
 519
 520        for (d = list; !dmi_is_end_of_table(d); d++)
 521                if (dmi_matches(d)) {
 522                        count++;
 523                        if (d->callback && d->callback(d))
 524                                break;
 525                }
 526
 527        return count;
 528}
 529EXPORT_SYMBOL(dmi_check_system);
 530
 531/**
 532 *      dmi_first_match - find dmi_system_id structure matching system DMI data
 533 *      @list: array of dmi_system_id structures to match against
 534 *              All non-null elements of the list must match
 535 *              their slot's (field index's) data (i.e., each
 536 *              list string must be a substring of the specified
 537 *              DMI slot's string data) to be considered a
 538 *              successful match.
 539 *
 540 *      Walk the blacklist table until the first match is found.  Return the
 541 *      pointer to the matching entry or NULL if there's no match.
 542 */
 543const struct dmi_system_id *dmi_first_match(const struct dmi_system_id *list)
 544{
 545        const struct dmi_system_id *d;
 546
 547        for (d = list; !dmi_is_end_of_table(d); d++)
 548                if (dmi_matches(d))
 549                        return d;
 550
 551        return NULL;
 552}
 553EXPORT_SYMBOL(dmi_first_match);
 554
 555/**
 556 *      dmi_get_system_info - return DMI data value
 557 *      @field: data index (see enum dmi_field)
 558 *
 559 *      Returns one DMI data value, can be used to perform
 560 *      complex DMI data checks.
 561 */
 562const char *dmi_get_system_info(int field)
 563{
 564        return dmi_ident[field];
 565}
 566EXPORT_SYMBOL(dmi_get_system_info);
 567
 568/**
 569 * dmi_name_in_serial - Check if string is in the DMI product serial information
 570 * @str: string to check for
 571 */
 572int dmi_name_in_serial(const char *str)
 573{
 574        int f = DMI_PRODUCT_SERIAL;
 575        if (dmi_ident[f] && strstr(dmi_ident[f], str))
 576                return 1;
 577        return 0;
 578}
 579
 580/**
 581 *      dmi_name_in_vendors - Check if string is anywhere in the DMI vendor information.
 582 *      @str:   Case sensitive Name
 583 */
 584int dmi_name_in_vendors(const char *str)
 585{
 586        static int fields[] = { DMI_BIOS_VENDOR, DMI_BIOS_VERSION, DMI_SYS_VENDOR,
 587                                DMI_PRODUCT_NAME, DMI_PRODUCT_VERSION, DMI_BOARD_VENDOR,
 588                                DMI_BOARD_NAME, DMI_BOARD_VERSION, DMI_NONE };
 589        int i;
 590        for (i = 0; fields[i] != DMI_NONE; i++) {
 591                int f = fields[i];
 592                if (dmi_ident[f] && strstr(dmi_ident[f], str))
 593                        return 1;
 594        }
 595        return 0;
 596}
 597EXPORT_SYMBOL(dmi_name_in_vendors);
 598
 599/**
 600 *      dmi_find_device - find onboard device by type/name
 601 *      @type: device type or %DMI_DEV_TYPE_ANY to match all device types
 602 *      @name: device name string or %NULL to match all
 603 *      @from: previous device found in search, or %NULL for new search.
 604 *
 605 *      Iterates through the list of known onboard devices. If a device is
 606 *      found with a matching @vendor and @device, a pointer to its device
 607 *      structure is returned.  Otherwise, %NULL is returned.
 608 *      A new search is initiated by passing %NULL as the @from argument.
 609 *      If @from is not %NULL, searches continue from next device.
 610 */
 611const struct dmi_device * dmi_find_device(int type, const char *name,
 612                                    const struct dmi_device *from)
 613{
 614        const struct list_head *head = from ? &from->list : &dmi_devices;
 615        struct list_head *d;
 616
 617        for(d = head->next; d != &dmi_devices; d = d->next) {
 618                const struct dmi_device *dev =
 619                        list_entry(d, struct dmi_device, list);
 620
 621                if (((type == DMI_DEV_TYPE_ANY) || (dev->type == type)) &&
 622                    ((name == NULL) || (strcmp(dev->name, name) == 0)))
 623                        return dev;
 624        }
 625
 626        return NULL;
 627}
 628EXPORT_SYMBOL(dmi_find_device);
 629
 630/**
 631 *      dmi_get_date - parse a DMI date
 632 *      @field: data index (see enum dmi_field)
 633 *      @yearp: optional out parameter for the year
 634 *      @monthp: optional out parameter for the month
 635 *      @dayp: optional out parameter for the day
 636 *
 637 *      The date field is assumed to be in the form resembling
 638 *      [mm[/dd]]/yy[yy] and the result is stored in the out
 639 *      parameters any or all of which can be omitted.
 640 *
 641 *      If the field doesn't exist, all out parameters are set to zero
 642 *      and false is returned.  Otherwise, true is returned with any
 643 *      invalid part of date set to zero.
 644 *
 645 *      On return, year, month and day are guaranteed to be in the
 646 *      range of [0,9999], [0,12] and [0,31] respectively.
 647 */
 648bool dmi_get_date(int field, int *yearp, int *monthp, int *dayp)
 649{
 650        int year = 0, month = 0, day = 0;
 651        bool exists;
 652        const char *s, *y;
 653        char *e;
 654
 655        s = dmi_get_system_info(field);
 656        exists = s;
 657        if (!exists)
 658                goto out;
 659
 660        /*
 661         * Determine year first.  We assume the date string resembles
 662         * mm/dd/yy[yy] but the original code extracted only the year
 663         * from the end.  Keep the behavior in the spirit of no
 664         * surprises.
 665         */
 666        y = strrchr(s, '/');
 667        if (!y)
 668                goto out;
 669
 670        y++;
 671        year = simple_strtoul(y, &e, 10);
 672        if (y != e && year < 100) {     /* 2-digit year */
 673                year += 1900;
 674                if (year < 1996)        /* no dates < spec 1.0 */
 675                        year += 100;
 676        }
 677        if (year > 9999)                /* year should fit in %04d */
 678                year = 0;
 679
 680        /* parse the mm and dd */
 681        month = simple_strtoul(s, &e, 10);
 682        if (s == e || *e != '/' || !month || month > 12) {
 683                month = 0;
 684                goto out;
 685        }
 686
 687        s = e + 1;
 688        day = simple_strtoul(s, &e, 10);
 689        if (s == y || s == e || *e != '/' || day > 31)
 690                day = 0;
 691out:
 692        if (yearp)
 693                *yearp = year;
 694        if (monthp)
 695                *monthp = month;
 696        if (dayp)
 697                *dayp = day;
 698        return exists;
 699}
 700EXPORT_SYMBOL(dmi_get_date);
 701
 702/**
 703 *      dmi_walk - Walk the DMI table and get called back for every record
 704 *      @decode: Callback function
 705 *      @private_data: Private data to be passed to the callback function
 706 *
 707 *      Returns -1 when the DMI table can't be reached, 0 on success.
 708 */
 709int dmi_walk(void (*decode)(const struct dmi_header *, void *),
 710             void *private_data)
 711{
 712        u8 *buf;
 713
 714        if (!dmi_available)
 715                return -1;
 716
 717        buf = ioremap(dmi_base, dmi_len);
 718        if (buf == NULL)
 719                return -1;
 720
 721        dmi_table(buf, dmi_len, dmi_num, decode, private_data);
 722
 723        iounmap(buf);
 724        return 0;
 725}
 726EXPORT_SYMBOL_GPL(dmi_walk);
 727
 728/**
 729 * dmi_match - compare a string to the dmi field (if exists)
 730 * @f: DMI field identifier
 731 * @str: string to compare the DMI field to
 732 *
 733 * Returns true if the requested field equals to the str (including NULL).
 734 */
 735bool dmi_match(enum dmi_field f, const char *str)
 736{
 737        const char *info = dmi_get_system_info(f);
 738
 739        if (info == NULL || str == NULL)
 740                return info == str;
 741
 742        return !strcmp(info, str);
 743}
 744EXPORT_SYMBOL_GPL(dmi_match);
 745