drivers/acpi/tables/tbxfroot.c

   1 /******************************************************************************
   2  *
   3  * Module Name: tbxfroot - Find the root ACPI table (RSDT)
   4  *
   5  *****************************************************************************/
   6
   7 /*
   8  * Copyright (C) 2000 - 2006, R. Byron Moore
   9  * All rights reserved.
  10  *
  11  * Redistribution and use in source and binary forms, with or without
  12  * modification, are permitted provided that the following conditions
  13  * are met:
  14  * 1. Redistributions of source code must retain the above copyright
  15  *    notice, this list of conditions, and the following disclaimer,
  16  *    without modification.
  17  * 2. Redistributions in binary form must reproduce at minimum a disclaimer
  18  *    substantially similar to the "NO WARRANTY" disclaimer below
  19  *    ("Disclaimer") and any redistribution must be conditioned upon
  20  *    including a substantially similar Disclaimer requirement for further
  21  *    binary redistribution.
  22  * 3. Neither the names of the above-listed copyright holders nor the names
  23  *    of any contributors may be used to endorse or promote products derived
  24  *    from this software without specific prior written permission.
  25  *
  26  * Alternatively, this software may be distributed under the terms of the
  27  * GNU General Public License ("GPL") version 2 as published by the Free
  28  * Software Foundation.
  29  *
  30  * NO WARRANTY
  31  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  32  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  33  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
  34  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  35  * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  36  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  37  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  38  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  39  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
  40  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  41  * POSSIBILITY OF SUCH DAMAGES.
  42  */
  43
  44 #include <linux/module.h>
  45
  46 #include <acpi/acpi.h>
  47 #include <acpi/actables.h>
  48
  49 #define _COMPONENT          ACPI_TABLES
  50 ACPI_MODULE_NAME("tbxfroot")
  51
  52 /* Local prototypes */
  53 static acpi_status
  54 acpi_tb_find_rsdp(struct acpi_table_desc *table_info, u32 flags);
  55
  56 static u8 *acpi_tb_scan_memory_for_rsdp(u8 * start_address, u32 length);
  57
  58 /*******************************************************************************
  59  *
  60  * FUNCTION:    acpi_tb_validate_rsdp
  61  *
  62  * PARAMETERS:  Rsdp        - Pointer to unvalidated RSDP
  63  *
  64  * RETURN:      Status
  65  *
  66  * DESCRIPTION: Validate the RSDP (ptr)
  67  *
  68  ******************************************************************************/
  69
  70 acpi_status acpi_tb_validate_rsdp(struct rsdp_descriptor *rsdp)
  71 {
  72         ACPI_FUNCTION_ENTRY();
  73
  74         /*
  75          *  The signature and checksum must both be correct
  76          */
  77         if (ACPI_STRNCMP((char *)rsdp, RSDP_SIG, sizeof(RSDP_SIG) - 1) != 0) {
  78                 /* Nope, BAD Signature */
  79
  80                 return (AE_BAD_SIGNATURE);
  81         }
  82
  83         /* Check the standard checksum */
  84
  85         if (acpi_tb_generate_checksum(rsdp, ACPI_RSDP_CHECKSUM_LENGTH) != 0) {
  86                 return (AE_BAD_CHECKSUM);
  87         }
  88
  89         /* Check extended checksum if table version >= 2 */
  90
  91         if ((rsdp->revision >= 2) &&
  92             (acpi_tb_generate_checksum(rsdp, ACPI_RSDP_XCHECKSUM_LENGTH) !=
  93              0)) {
  94                 return (AE_BAD_CHECKSUM);
  95         }
  96
  97         return (AE_OK);
  98 }
  99
 100 /*******************************************************************************
 101  *
 102  * FUNCTION:    acpi_tb_find_table
 103  *
 104  * PARAMETERS:  Signature           - String with ACPI table signature
 105  *              oem_id              - String with the table OEM ID
 106  *              oem_table_id        - String with the OEM Table ID
 107  *              table_ptr           - Where the table pointer is returned
 108  *
 109  * RETURN:      Status
 110  *
 111  * DESCRIPTION: Find an ACPI table (in the RSDT/XSDT) that matches the
 112  *              Signature, OEM ID and OEM Table ID.
 113  *
 114  ******************************************************************************/
 115
 116 acpi_status
 117 acpi_tb_find_table(char *signature,
 118                    char *oem_id,
 119                    char *oem_table_id, struct acpi_table_header ** table_ptr)
 120 {
 121         acpi_status status;
 122         struct acpi_table_header *table;
 123
 124         ACPI_FUNCTION_TRACE("tb_find_table");
 125
 126         /* Validate string lengths */
 127
 128         if ((ACPI_STRLEN(signature) > ACPI_NAME_SIZE) ||
 129             (ACPI_STRLEN(oem_id) > sizeof(table->oem_id)) ||
 130             (ACPI_STRLEN(oem_table_id) > sizeof(table->oem_table_id))) {
 131                 return_ACPI_STATUS(AE_AML_STRING_LIMIT);
 132         }
 133
 134         if (!ACPI_STRNCMP(signature, DSDT_SIG, ACPI_NAME_SIZE)) {
 135                 /*
 136                  * The DSDT pointer is contained in the FADT, not the RSDT.
 137                  * This code should suffice, because the only code that would perform
 138                  * a "find" on the DSDT is the data_table_region() AML opcode -- in
 139                  * which case, the DSDT is guaranteed to be already loaded.
 140                  * If this becomes insufficient, the FADT will have to be found first.
 141                  */
 142                 if (!acpi_gbl_DSDT) {
 143                         return_ACPI_STATUS(AE_NO_ACPI_TABLES);
 144                 }
 145                 table = acpi_gbl_DSDT;
 146         } else {
 147                 /* Find the table */
 148
 149                 status = acpi_get_firmware_table(signature, 1,
 150                                                  ACPI_LOGICAL_ADDRESSING,
 151                                                  &table);
 152                 if (ACPI_FAILURE(status)) {
 153                         return_ACPI_STATUS(status);
 154                 }
 155         }
 156
 157         /* Check oem_id and oem_table_id */
 158
 159         if ((oem_id[0] && ACPI_STRNCMP(oem_id, table->oem_id,
 160                                        sizeof(table->oem_id))) ||
 161             (oem_table_id[0] && ACPI_STRNCMP(oem_table_id, table->oem_table_id,
 162                                              sizeof(table->oem_table_id)))) {
 163                 return_ACPI_STATUS(AE_AML_NAME_NOT_FOUND);
 164         }
 165
 166         ACPI_DEBUG_PRINT((ACPI_DB_TABLES, "Found table [%4.4s]\n",
 167                           table->signature));
 168
 169         *table_ptr = table;
 170         return_ACPI_STATUS(AE_OK);
 171 }
 172
 173 /*******************************************************************************
 174  *
 175  * FUNCTION:    acpi_get_firmware_table
 176  *
 177  * PARAMETERS:  Signature       - Any ACPI table signature
 178  *              Instance        - the non zero instance of the table, allows
 179  *                                support for multiple tables of the same type
 180  *              Flags           - Physical/Virtual support
 181  *              table_pointer   - Where a buffer containing the table is
 182  *                                returned
 183  *
 184  * RETURN:      Status
 185  *
 186  * DESCRIPTION: This function is called to get an ACPI table. A buffer is
 187  *              allocated for the table and returned in table_pointer.
 188  *              This table will be a complete table including the header.
 189  *
 190  ******************************************************************************/
 191
 192 acpi_status
 193 acpi_get_firmware_table(acpi_string signature,
 194                         u32 instance,
 195                         u32 flags, struct acpi_table_header **table_pointer)
 196 {
 197         acpi_status status;
 198         struct acpi_pointer address;
 199         struct acpi_table_header *header = NULL;
 200         struct acpi_table_desc *table_info = NULL;
 201         struct acpi_table_desc *rsdt_info;
 202         u32 table_count;
 203         u32 i;
 204         u32 j;
 205
 206         ACPI_FUNCTION_TRACE("acpi_get_firmware_table");
 207
 208         /*
 209          * Ensure that at least the table manager is initialized.  We don't
 210          * require that the entire ACPI subsystem is up for this interface.
 211          * If we have a buffer, we must have a length too
 212          */
 213         if ((instance == 0) || (!signature) || (!table_pointer)) {
 214                 return_ACPI_STATUS(AE_BAD_PARAMETER);
 215         }
 216
 217         /* Ensure that we have a RSDP */
 218
 219         if (!acpi_gbl_RSDP) {
 220                 /* Get the RSDP */
 221
 222                 status = acpi_os_get_root_pointer(flags, &address);
 223                 if (ACPI_FAILURE(status)) {
 224                         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "RSDP not found\n"));
 225                         return_ACPI_STATUS(AE_NO_ACPI_TABLES);
 226                 }
 227
 228                 /* Map and validate the RSDP */
 229
 230                 if ((flags & ACPI_MEMORY_MODE) == ACPI_LOGICAL_ADDRESSING) {
 231                         status = acpi_os_map_memory(address.pointer.physical,
 232                                                     sizeof(struct
 233                                                            rsdp_descriptor),
 234                                                     (void *)&acpi_gbl_RSDP);
 235                         if (ACPI_FAILURE(status)) {
 236                                 return_ACPI_STATUS(status);
 237                         }
 238                 } else {
 239                         acpi_gbl_RSDP = address.pointer.logical;
 240                 }
 241
 242                 /* The RDSP signature and checksum must both be correct */
 243
 244                 status = acpi_tb_validate_rsdp(acpi_gbl_RSDP);
 245                 if (ACPI_FAILURE(status)) {
 246                         return_ACPI_STATUS(status);
 247                 }
 248         }
 249
 250         /* Get the RSDT address via the RSDP */
 251
 252         acpi_tb_get_rsdt_address(&address);
 253         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 254                           "RSDP located at %p, RSDT physical=%8.8X%8.8X\n",
 255                           acpi_gbl_RSDP,
 256                           ACPI_FORMAT_UINT64(address.pointer.value)));
 257
 258         /* Insert processor_mode flags */
 259
 260         address.pointer_type |= flags;
 261
 262         /* Get and validate the RSDT */
 263
 264         rsdt_info = ACPI_MEM_CALLOCATE(sizeof(struct acpi_table_desc));
 265         if (!rsdt_info) {
 266                 return_ACPI_STATUS(AE_NO_MEMORY);
 267         }
 268
 269         status = acpi_tb_get_table(&address, rsdt_info);
 270         if (ACPI_FAILURE(status)) {
 271                 goto cleanup;
 272         }
 273
 274         status = acpi_tb_validate_rsdt(rsdt_info->pointer);
 275         if (ACPI_FAILURE(status)) {
 276                 goto cleanup;
 277         }
 278
 279         /* Allocate a scratch table header and table descriptor */
 280
 281         header = ACPI_MEM_ALLOCATE(sizeof(struct acpi_table_header));
 282         if (!header) {
 283                 status = AE_NO_MEMORY;
 284                 goto cleanup;
 285         }
 286
 287         table_info = ACPI_MEM_ALLOCATE(sizeof(struct acpi_table_desc));
 288         if (!table_info) {
 289                 status = AE_NO_MEMORY;
 290                 goto cleanup;
 291         }
 292
 293         /* Get the number of table pointers within the RSDT */
 294
 295         table_count =
 296             acpi_tb_get_table_count(acpi_gbl_RSDP, rsdt_info->pointer);
 297         address.pointer_type = acpi_gbl_table_flags | flags;
 298
 299         /*
 300          * Search the RSDT/XSDT for the correct instance of the
 301          * requested table
 302          */
 303         for (i = 0, j = 0; i < table_count; i++) {
 304                 /*
 305                  * Get the next table pointer, handle RSDT vs. XSDT
 306                  * RSDT pointers are 32 bits, XSDT pointers are 64 bits
 307                  */
 308                 if (acpi_gbl_root_table_type == ACPI_TABLE_TYPE_RSDT) {
 309                         address.pointer.value =
 310                             (ACPI_CAST_PTR
 311                              (RSDT_DESCRIPTOR,
 312                               rsdt_info->pointer))->table_offset_entry[i];
 313                 } else {
 314                         address.pointer.value =
 315                             (ACPI_CAST_PTR
 316                              (XSDT_DESCRIPTOR,
 317                               rsdt_info->pointer))->table_offset_entry[i];
 318                 }
 319
 320                 /* Get the table header */
 321
 322                 status = acpi_tb_get_table_header(&address, header);
 323                 if (ACPI_FAILURE(status)) {
 324                         goto cleanup;
 325                 }
 326
 327                 /* Compare table signatures and table instance */
 328
 329                 if (!ACPI_STRNCMP(header->signature, signature, ACPI_NAME_SIZE)) {
 330                         /* An instance of the table was found */
 331
 332                         j++;
 333                         if (j >= instance) {
 334                                 /* Found the correct instance, get the entire table */
 335
 336                                 status =
 337                                     acpi_tb_get_table_body(&address, header,
 338                                                            table_info);
 339                                 if (ACPI_FAILURE(status)) {
 340                                         goto cleanup;
 341                                 }
 342
 343                                 *table_pointer = table_info->pointer;
 344                                 goto cleanup;
 345                         }
 346                 }
 347         }
 348
 349         /* Did not find the table */
 350
 351         status = AE_NOT_EXIST;
 352
 353       cleanup:
 354         if (rsdt_info->pointer) {
 355                 acpi_os_unmap_memory(rsdt_info->pointer,
 356                                      (acpi_size) rsdt_info->pointer->length);
 357         }
 358         ACPI_MEM_FREE(rsdt_info);
 359
 360         if (header) {
 361                 ACPI_MEM_FREE(header);
 362         }
 363         if (table_info) {
 364                 ACPI_MEM_FREE(table_info);
 365         }
 366         return_ACPI_STATUS(status);
 367 }
 368
 369 EXPORT_SYMBOL(acpi_get_firmware_table);
 370
 371 /* TBD: Move to a new file */
 372
 373 #if ACPI_MACHINE_WIDTH != 16
 374
 375 /*******************************************************************************
 376  *
 377  * FUNCTION:    acpi_find_root_pointer
 378  *
 379  * PARAMETERS:  Flags                   - Logical/Physical addressing
 380  *              rsdp_address            - Where to place the RSDP address
 381  *
 382  * RETURN:      Status, Physical address of the RSDP
 383  *
 384  * DESCRIPTION: Find the RSDP
 385  *
 386  ******************************************************************************/
 387
 388 acpi_status acpi_find_root_pointer(u32 flags, struct acpi_pointer *rsdp_address)
 389 {
 390         struct acpi_table_desc table_info;
 391         acpi_status status;
 392
 393         ACPI_FUNCTION_TRACE("acpi_find_root_pointer");
 394
 395         /* Get the RSDP */
 396
 397         status = acpi_tb_find_rsdp(&table_info, flags);
 398         if (ACPI_FAILURE(status)) {
 399                 ACPI_EXCEPTION((AE_INFO, status,
 400                                 "RSDP structure not found - Flags=%X", flags));
 401
 402                 return_ACPI_STATUS(AE_NO_ACPI_TABLES);
 403         }
 404
 405         rsdp_address->pointer_type = ACPI_PHYSICAL_POINTER;
 406         rsdp_address->pointer.physical = table_info.physical_address;
 407         return_ACPI_STATUS(AE_OK);
 408 }
 409
 410 /*******************************************************************************
 411  *
 412  * FUNCTION:    acpi_tb_scan_memory_for_rsdp
 413  *
 414  * PARAMETERS:  start_address       - Starting pointer for search
 415  *              Length              - Maximum length to search
 416  *
 417  * RETURN:      Pointer to the RSDP if found, otherwise NULL.
 418  *
 419  * DESCRIPTION: Search a block of memory for the RSDP signature
 420  *
 421  ******************************************************************************/
 422
 423 static u8 *acpi_tb_scan_memory_for_rsdp(u8 * start_address, u32 length)
 424 {
 425         acpi_status status;
 426         u8 *mem_rover;
 427         u8 *end_address;
 428
 429         ACPI_FUNCTION_TRACE("tb_scan_memory_for_rsdp");
 430
 431         end_address = start_address + length;
 432
 433         /* Search from given start address for the requested length */
 434
 435         for (mem_rover = start_address; mem_rover < end_address;
 436              mem_rover += ACPI_RSDP_SCAN_STEP) {
 437                 /* The RSDP signature and checksum must both be correct */
 438
 439                 status =
 440                     acpi_tb_validate_rsdp(ACPI_CAST_PTR
 441                                           (struct rsdp_descriptor, mem_rover));
 442                 if (ACPI_SUCCESS(status)) {
 443                         /* Sig and checksum valid, we have found a real RSDP */
 444
 445                         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 446                                           "RSDP located at physical address %p\n",
 447                                           mem_rover));
 448                         return_PTR(mem_rover);
 449                 }
 450
 451                 /* No sig match or bad checksum, keep searching */
 452         }
 453
 454         /* Searched entire block, no RSDP was found */
 455
 456         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 457                           "Searched entire block from %p, valid RSDP was not found\n",
 458                           start_address));
 459         return_PTR(NULL);
 460 }
 461
 462 /*******************************************************************************
 463  *
 464  * FUNCTION:    acpi_tb_find_rsdp
 465  *
 466  * PARAMETERS:  table_info              - Where the table info is returned
 467  *              Flags                   - Current memory mode (logical vs.
 468  *                                        physical addressing)
 469  *
 470  * RETURN:      Status, RSDP physical address
 471  *
 472  * DESCRIPTION: search lower 1_mbyte of memory for the root system descriptor
 473  *              pointer structure.  If it is found, set *RSDP to point to it.
 474  *
 475  *              NOTE1: The RSDp must be either in the first 1_k of the Extended
 476  *              BIOS Data Area or between E0000 and FFFFF (From ACPI Spec.)
 477  *              Only a 32-bit physical address is necessary.
 478  *
 479  *              NOTE2: This function is always available, regardless of the
 480  *              initialization state of the rest of ACPI.
 481  *
 482  ******************************************************************************/
 483
 484 static acpi_status
 485 acpi_tb_find_rsdp(struct acpi_table_desc *table_info, u32 flags)
 486 {
 487         u8 *table_ptr;
 488         u8 *mem_rover;
 489         u32 physical_address;
 490         acpi_status status;
 491
 492         ACPI_FUNCTION_TRACE("tb_find_rsdp");
 493
 494         /*
 495          * Scan supports either logical addressing or physical addressing
 496          */
 497         if ((flags & ACPI_MEMORY_MODE) == ACPI_LOGICAL_ADDRESSING) {
 498                 /* 1a) Get the location of the Extended BIOS Data Area (EBDA) */
 499
 500                 status = acpi_os_map_memory((acpi_physical_address)
 501                                             ACPI_EBDA_PTR_LOCATION,
 502                                             ACPI_EBDA_PTR_LENGTH,
 503                                             (void *)&table_ptr);
 504                 if (ACPI_FAILURE(status)) {
 505                         ACPI_ERROR((AE_INFO,
 506                                     "Could not map memory at %8.8X for length %X",
 507                                     ACPI_EBDA_PTR_LOCATION,
 508                                     ACPI_EBDA_PTR_LENGTH));
 509
 510                         return_ACPI_STATUS(status);
 511                 }
 512
 513                 ACPI_MOVE_16_TO_32(&physical_address, table_ptr);
 514
 515                 /* Convert segment part to physical address */
 516
 517                 physical_address <<= 4;
 518                 acpi_os_unmap_memory(table_ptr, ACPI_EBDA_PTR_LENGTH);
 519
 520                 /* EBDA present? */
 521
 522                 if (physical_address > 0x400) {
 523                         /*
 524                          * 1b) Search EBDA paragraphs (EBDa is required to be a
 525                          *     minimum of 1_k length)
 526                          */
 527                         status = acpi_os_map_memory((acpi_physical_address)
 528                                                     physical_address,
 529                                                     ACPI_EBDA_WINDOW_SIZE,
 530                                                     (void *)&table_ptr);
 531                         if (ACPI_FAILURE(status)) {
 532                                 ACPI_ERROR((AE_INFO,
 533                                             "Could not map memory at %8.8X for length %X",
 534                                             physical_address,
 535                                             ACPI_EBDA_WINDOW_SIZE));
 536
 537                                 return_ACPI_STATUS(status);
 538                         }
 539
 540                         mem_rover = acpi_tb_scan_memory_for_rsdp(table_ptr,
 541                                                                  ACPI_EBDA_WINDOW_SIZE);
 542                         acpi_os_unmap_memory(table_ptr, ACPI_EBDA_WINDOW_SIZE);
 543
 544                         if (mem_rover) {
 545                                 /* Return the physical address */
 546
 547                                 physical_address +=
 548                                     ACPI_PTR_DIFF(mem_rover, table_ptr);
 549
 550                                 table_info->physical_address =
 551                                     (acpi_physical_address) physical_address;
 552                                 return_ACPI_STATUS(AE_OK);
 553                         }
 554                 }
 555
 556                 /*
 557                  * 2) Search upper memory: 16-byte boundaries in E0000h-FFFFFh
 558                  */
 559                 status = acpi_os_map_memory((acpi_physical_address)
 560                                             ACPI_HI_RSDP_WINDOW_BASE,
 561                                             ACPI_HI_RSDP_WINDOW_SIZE,
 562                                             (void *)&table_ptr);
 563
 564                 if (ACPI_FAILURE(status)) {
 565                         ACPI_ERROR((AE_INFO,
 566                                     "Could not map memory at %8.8X for length %X",
 567                                     ACPI_HI_RSDP_WINDOW_BASE,
 568                                     ACPI_HI_RSDP_WINDOW_SIZE));
 569
 570                         return_ACPI_STATUS(status);
 571                 }
 572
 573                 mem_rover =
 574                     acpi_tb_scan_memory_for_rsdp(table_ptr,
 575                                                  ACPI_HI_RSDP_WINDOW_SIZE);
 576                 acpi_os_unmap_memory(table_ptr, ACPI_HI_RSDP_WINDOW_SIZE);
 577
 578                 if (mem_rover) {
 579                         /* Return the physical address */
 580
 581                         physical_address =
 582                             ACPI_HI_RSDP_WINDOW_BASE + ACPI_PTR_DIFF(mem_rover,
 583                                                                      table_ptr);
 584
 585                         table_info->physical_address =
 586                             (acpi_physical_address) physical_address;
 587                         return_ACPI_STATUS(AE_OK);
 588                 }
 589         }
 590
 591         /*
 592          * Physical addressing
 593          */
 594         else {
 595                 /* 1a) Get the location of the EBDA */
 596
 597                 ACPI_MOVE_16_TO_32(&physical_address, ACPI_EBDA_PTR_LOCATION);
 598                 physical_address <<= 4; /* Convert segment to physical address */
 599
 600                 /* EBDA present? */
 601
 602                 if (physical_address > 0x400) {
 603                         /*
 604                          * 1b) Search EBDA paragraphs (EBDa is required to be a minimum of
 605                          *     1_k length)
 606                          */
 607                         mem_rover =
 608                             acpi_tb_scan_memory_for_rsdp(ACPI_PHYSADDR_TO_PTR
 609                                                          (physical_address),
 610                                                          ACPI_EBDA_WINDOW_SIZE);
 611                         if (mem_rover) {
 612                                 /* Return the physical address */
 613
 614                                 table_info->physical_address =
 615                                     ACPI_TO_INTEGER(mem_rover);
 616                                 return_ACPI_STATUS(AE_OK);
 617                         }
 618                 }
 619
 620                 /* 2) Search upper memory: 16-byte boundaries in E0000h-FFFFFh */
 621
 622                 mem_rover =
 623                     acpi_tb_scan_memory_for_rsdp(ACPI_PHYSADDR_TO_PTR
 624                                                  (ACPI_HI_RSDP_WINDOW_BASE),
 625                                                  ACPI_HI_RSDP_WINDOW_SIZE);
 626                 if (mem_rover) {
 627                         /* Found it, return the physical address */
 628
 629                         table_info->physical_address =
 630                             ACPI_TO_INTEGER(mem_rover);
 631                         return_ACPI_STATUS(AE_OK);
 632                 }
 633         }
 634
 635         /* A valid RSDP was not found */
 636
 637         ACPI_ERROR((AE_INFO, "No valid RSDP was found"));
 638         return_ACPI_STATUS(AE_NOT_FOUND);
 639 }
 640
 641 #endif