linux/drivers/acpi/acpica/tbfadt.c
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   1/******************************************************************************
   2 *
   3 * Module Name: tbfadt   - FADT table utilities
   4 *
   5 *****************************************************************************/
   6
   7/*
   8 * Copyright (C) 2000 - 2011, Intel Corp.
   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 <acpi/acpi.h>
  45#include "accommon.h"
  46#include "actables.h"
  47
  48#define _COMPONENT          ACPI_TABLES
  49ACPI_MODULE_NAME("tbfadt")
  50
  51/* Local prototypes */
  52static ACPI_INLINE void
  53acpi_tb_init_generic_address(struct acpi_generic_address *generic_address,
  54                             u8 space_id, u8 byte_width, u64 address);
  55
  56static void acpi_tb_convert_fadt(void);
  57
  58static void acpi_tb_validate_fadt(void);
  59
  60static void acpi_tb_setup_fadt_registers(void);
  61
  62/* Table for conversion of FADT to common internal format and FADT validation */
  63
  64typedef struct acpi_fadt_info {
  65        char *name;
  66        u8 address64;
  67        u8 address32;
  68        u8 length;
  69        u8 default_length;
  70        u8 type;
  71
  72} acpi_fadt_info;
  73
  74#define ACPI_FADT_REQUIRED          1
  75#define ACPI_FADT_SEPARATE_LENGTH   2
  76
  77static struct acpi_fadt_info fadt_info_table[] = {
  78        {"Pm1aEventBlock",
  79         ACPI_FADT_OFFSET(xpm1a_event_block),
  80         ACPI_FADT_OFFSET(pm1a_event_block),
  81         ACPI_FADT_OFFSET(pm1_event_length),
  82         ACPI_PM1_REGISTER_WIDTH * 2,   /* Enable + Status register */
  83         ACPI_FADT_REQUIRED},
  84
  85        {"Pm1bEventBlock",
  86         ACPI_FADT_OFFSET(xpm1b_event_block),
  87         ACPI_FADT_OFFSET(pm1b_event_block),
  88         ACPI_FADT_OFFSET(pm1_event_length),
  89         ACPI_PM1_REGISTER_WIDTH * 2,   /* Enable + Status register */
  90         0},
  91
  92        {"Pm1aControlBlock",
  93         ACPI_FADT_OFFSET(xpm1a_control_block),
  94         ACPI_FADT_OFFSET(pm1a_control_block),
  95         ACPI_FADT_OFFSET(pm1_control_length),
  96         ACPI_PM1_REGISTER_WIDTH,
  97         ACPI_FADT_REQUIRED},
  98
  99        {"Pm1bControlBlock",
 100         ACPI_FADT_OFFSET(xpm1b_control_block),
 101         ACPI_FADT_OFFSET(pm1b_control_block),
 102         ACPI_FADT_OFFSET(pm1_control_length),
 103         ACPI_PM1_REGISTER_WIDTH,
 104         0},
 105
 106        {"Pm2ControlBlock",
 107         ACPI_FADT_OFFSET(xpm2_control_block),
 108         ACPI_FADT_OFFSET(pm2_control_block),
 109         ACPI_FADT_OFFSET(pm2_control_length),
 110         ACPI_PM2_REGISTER_WIDTH,
 111         ACPI_FADT_SEPARATE_LENGTH},
 112
 113        {"PmTimerBlock",
 114         ACPI_FADT_OFFSET(xpm_timer_block),
 115         ACPI_FADT_OFFSET(pm_timer_block),
 116         ACPI_FADT_OFFSET(pm_timer_length),
 117         ACPI_PM_TIMER_WIDTH,
 118         ACPI_FADT_REQUIRED},
 119
 120        {"Gpe0Block",
 121         ACPI_FADT_OFFSET(xgpe0_block),
 122         ACPI_FADT_OFFSET(gpe0_block),
 123         ACPI_FADT_OFFSET(gpe0_block_length),
 124         0,
 125         ACPI_FADT_SEPARATE_LENGTH},
 126
 127        {"Gpe1Block",
 128         ACPI_FADT_OFFSET(xgpe1_block),
 129         ACPI_FADT_OFFSET(gpe1_block),
 130         ACPI_FADT_OFFSET(gpe1_block_length),
 131         0,
 132         ACPI_FADT_SEPARATE_LENGTH}
 133};
 134
 135#define ACPI_FADT_INFO_ENTRIES \
 136                        (sizeof (fadt_info_table) / sizeof (struct acpi_fadt_info))
 137
 138/* Table used to split Event Blocks into separate status/enable registers */
 139
 140typedef struct acpi_fadt_pm_info {
 141        struct acpi_generic_address *target;
 142        u8 source;
 143        u8 register_num;
 144
 145} acpi_fadt_pm_info;
 146
 147static struct acpi_fadt_pm_info fadt_pm_info_table[] = {
 148        {&acpi_gbl_xpm1a_status,
 149         ACPI_FADT_OFFSET(xpm1a_event_block),
 150         0},
 151
 152        {&acpi_gbl_xpm1a_enable,
 153         ACPI_FADT_OFFSET(xpm1a_event_block),
 154         1},
 155
 156        {&acpi_gbl_xpm1b_status,
 157         ACPI_FADT_OFFSET(xpm1b_event_block),
 158         0},
 159
 160        {&acpi_gbl_xpm1b_enable,
 161         ACPI_FADT_OFFSET(xpm1b_event_block),
 162         1}
 163};
 164
 165#define ACPI_FADT_PM_INFO_ENTRIES \
 166                        (sizeof (fadt_pm_info_table) / sizeof (struct acpi_fadt_pm_info))
 167
 168/*******************************************************************************
 169 *
 170 * FUNCTION:    acpi_tb_init_generic_address
 171 *
 172 * PARAMETERS:  generic_address     - GAS struct to be initialized
 173 *              byte_width          - Width of this register
 174 *              Address             - Address of the register
 175 *
 176 * RETURN:      None
 177 *
 178 * DESCRIPTION: Initialize a Generic Address Structure (GAS)
 179 *              See the ACPI specification for a full description and
 180 *              definition of this structure.
 181 *
 182 ******************************************************************************/
 183
 184static ACPI_INLINE void
 185acpi_tb_init_generic_address(struct acpi_generic_address *generic_address,
 186                             u8 space_id, u8 byte_width, u64 address)
 187{
 188
 189        /*
 190         * The 64-bit Address field is non-aligned in the byte packed
 191         * GAS struct.
 192         */
 193        ACPI_MOVE_64_TO_64(&generic_address->address, &address);
 194
 195        /* All other fields are byte-wide */
 196
 197        generic_address->space_id = space_id;
 198        generic_address->bit_width = (u8)ACPI_MUL_8(byte_width);
 199        generic_address->bit_offset = 0;
 200        generic_address->access_width = 0;      /* Access width ANY */
 201}
 202
 203/*******************************************************************************
 204 *
 205 * FUNCTION:    acpi_tb_parse_fadt
 206 *
 207 * PARAMETERS:  table_index         - Index for the FADT
 208 *
 209 * RETURN:      None
 210 *
 211 * DESCRIPTION: Initialize the FADT, DSDT and FACS tables
 212 *              (FADT contains the addresses of the DSDT and FACS)
 213 *
 214 ******************************************************************************/
 215
 216void acpi_tb_parse_fadt(u32 table_index)
 217{
 218        u32 length;
 219        struct acpi_table_header *table;
 220
 221        /*
 222         * The FADT has multiple versions with different lengths,
 223         * and it contains pointers to both the DSDT and FACS tables.
 224         *
 225         * Get a local copy of the FADT and convert it to a common format
 226         * Map entire FADT, assumed to be smaller than one page.
 227         */
 228        length = acpi_gbl_root_table_list.tables[table_index].length;
 229
 230        table =
 231            acpi_os_map_memory(acpi_gbl_root_table_list.tables[table_index].
 232                               address, length);
 233        if (!table) {
 234                return;
 235        }
 236
 237        /*
 238         * Validate the FADT checksum before we copy the table. Ignore
 239         * checksum error as we want to try to get the DSDT and FACS.
 240         */
 241        (void)acpi_tb_verify_checksum(table, length);
 242
 243        /* Create a local copy of the FADT in common ACPI 2.0+ format */
 244
 245        acpi_tb_create_local_fadt(table, length);
 246
 247        /* All done with the real FADT, unmap it */
 248
 249        acpi_os_unmap_memory(table, length);
 250
 251        /* Obtain the DSDT and FACS tables via their addresses within the FADT */
 252
 253        acpi_tb_install_table((acpi_physical_address) acpi_gbl_FADT.Xdsdt,
 254                              ACPI_SIG_DSDT, ACPI_TABLE_INDEX_DSDT);
 255
 256        acpi_tb_install_table((acpi_physical_address) acpi_gbl_FADT.Xfacs,
 257                              ACPI_SIG_FACS, ACPI_TABLE_INDEX_FACS);
 258}
 259
 260/*******************************************************************************
 261 *
 262 * FUNCTION:    acpi_tb_create_local_fadt
 263 *
 264 * PARAMETERS:  Table               - Pointer to BIOS FADT
 265 *              Length              - Length of the table
 266 *
 267 * RETURN:      None
 268 *
 269 * DESCRIPTION: Get a local copy of the FADT and convert it to a common format.
 270 *              Performs validation on some important FADT fields.
 271 *
 272 * NOTE:        We create a local copy of the FADT regardless of the version.
 273 *
 274 ******************************************************************************/
 275
 276void acpi_tb_create_local_fadt(struct acpi_table_header *table, u32 length)
 277{
 278        /*
 279         * Check if the FADT is larger than the largest table that we expect
 280         * (the ACPI 2.0/3.0 version). If so, truncate the table, and issue
 281         * a warning.
 282         */
 283        if (length > sizeof(struct acpi_table_fadt)) {
 284                ACPI_WARNING((AE_INFO,
 285                              "FADT (revision %u) is longer than ACPI 2.0 version, "
 286                              "truncating length %u to %u",
 287                              table->revision, length,
 288                              (u32)sizeof(struct acpi_table_fadt)));
 289        }
 290
 291        /* Clear the entire local FADT */
 292
 293        ACPI_MEMSET(&acpi_gbl_FADT, 0, sizeof(struct acpi_table_fadt));
 294
 295        /* Copy the original FADT, up to sizeof (struct acpi_table_fadt) */
 296
 297        ACPI_MEMCPY(&acpi_gbl_FADT, table,
 298                    ACPI_MIN(length, sizeof(struct acpi_table_fadt)));
 299
 300        /* Convert the local copy of the FADT to the common internal format */
 301
 302        acpi_tb_convert_fadt();
 303
 304        /* Validate FADT values now, before we make any changes */
 305
 306        acpi_tb_validate_fadt();
 307
 308        /* Initialize the global ACPI register structures */
 309
 310        acpi_tb_setup_fadt_registers();
 311}
 312
 313/*******************************************************************************
 314 *
 315 * FUNCTION:    acpi_tb_convert_fadt
 316 *
 317 * PARAMETERS:  None, uses acpi_gbl_FADT
 318 *
 319 * RETURN:      None
 320 *
 321 * DESCRIPTION: Converts all versions of the FADT to a common internal format.
 322 *              Expand 32-bit addresses to 64-bit as necessary.
 323 *
 324 * NOTE:        acpi_gbl_FADT must be of size (struct acpi_table_fadt),
 325 *              and must contain a copy of the actual FADT.
 326 *
 327 * Notes on 64-bit register addresses:
 328 *
 329 * After this FADT conversion, later ACPICA code will only use the 64-bit "X"
 330 * fields of the FADT for all ACPI register addresses.
 331 *
 332 * The 64-bit "X" fields are optional extensions to the original 32-bit FADT
 333 * V1.0 fields. Even if they are present in the FADT, they are optional and
 334 * are unused if the BIOS sets them to zero. Therefore, we must copy/expand
 335 * 32-bit V1.0 fields if the corresponding X field is zero.
 336 *
 337 * For ACPI 1.0 FADTs, all 32-bit address fields are expanded to the
 338 * corresponding "X" fields in the internal FADT.
 339 *
 340 * For ACPI 2.0+ FADTs, all valid (non-zero) 32-bit address fields are expanded
 341 * to the corresponding 64-bit X fields. For compatibility with other ACPI
 342 * implementations, we ignore the 64-bit field if the 32-bit field is valid,
 343 * regardless of whether the host OS is 32-bit or 64-bit.
 344 *
 345 ******************************************************************************/
 346
 347static void acpi_tb_convert_fadt(void)
 348{
 349        struct acpi_generic_address *address64;
 350        u32 address32;
 351        u32 i;
 352
 353        /* Update the local FADT table header length */
 354
 355        acpi_gbl_FADT.header.length = sizeof(struct acpi_table_fadt);
 356
 357        /*
 358         * Expand the 32-bit FACS and DSDT addresses to 64-bit as necessary.
 359         * Later code will always use the X 64-bit field. Also, check for an
 360         * address mismatch between the 32-bit and 64-bit address fields
 361         * (FIRMWARE_CTRL/X_FIRMWARE_CTRL, DSDT/X_DSDT) which would indicate
 362         * the presence of two FACS or two DSDT tables.
 363         */
 364        if (!acpi_gbl_FADT.Xfacs) {
 365                acpi_gbl_FADT.Xfacs = (u64) acpi_gbl_FADT.facs;
 366        } else if (acpi_gbl_FADT.facs &&
 367                   (acpi_gbl_FADT.Xfacs != (u64) acpi_gbl_FADT.facs)) {
 368                ACPI_WARNING((AE_INFO,
 369                    "32/64 FACS address mismatch in FADT - two FACS tables!"));
 370        }
 371
 372        if (!acpi_gbl_FADT.Xdsdt) {
 373                acpi_gbl_FADT.Xdsdt = (u64) acpi_gbl_FADT.dsdt;
 374        } else if (acpi_gbl_FADT.dsdt &&
 375                   (acpi_gbl_FADT.Xdsdt != (u64) acpi_gbl_FADT.dsdt)) {
 376                ACPI_WARNING((AE_INFO,
 377                    "32/64 DSDT address mismatch in FADT - two DSDT tables!"));
 378        }
 379
 380        /*
 381         * For ACPI 1.0 FADTs (revision 1 or 2), ensure that reserved fields which
 382         * should be zero are indeed zero. This will workaround BIOSs that
 383         * inadvertently place values in these fields.
 384         *
 385         * The ACPI 1.0 reserved fields that will be zeroed are the bytes located at
 386         * offset 45, 55, 95, and the word located at offset 109, 110.
 387         */
 388        if (acpi_gbl_FADT.header.revision < FADT2_REVISION_ID) {
 389                acpi_gbl_FADT.preferred_profile = 0;
 390                acpi_gbl_FADT.pstate_control = 0;
 391                acpi_gbl_FADT.cst_control = 0;
 392                acpi_gbl_FADT.boot_flags = 0;
 393        }
 394
 395        /*
 396         * Expand the ACPI 1.0 32-bit addresses to the ACPI 2.0 64-bit "X"
 397         * generic address structures as necessary. Later code will always use
 398         * the 64-bit address structures.
 399         *
 400         * March 2009:
 401         * We now always use the 32-bit address if it is valid (non-null). This
 402         * is not in accordance with the ACPI specification which states that
 403         * the 64-bit address supersedes the 32-bit version, but we do this for
 404         * compatibility with other ACPI implementations. Most notably, in the
 405         * case where both the 32 and 64 versions are non-null, we use the 32-bit
 406         * version. This is the only address that is guaranteed to have been
 407         * tested by the BIOS manufacturer.
 408         */
 409        for (i = 0; i < ACPI_FADT_INFO_ENTRIES; i++) {
 410                address32 = *ACPI_ADD_PTR(u32,
 411                                          &acpi_gbl_FADT,
 412                                          fadt_info_table[i].address32);
 413
 414                address64 = ACPI_ADD_PTR(struct acpi_generic_address,
 415                                         &acpi_gbl_FADT,
 416                                         fadt_info_table[i].address64);
 417
 418                /*
 419                 * If both 32- and 64-bit addresses are valid (non-zero),
 420                 * they must match.
 421                 */
 422                if (address64->address && address32 &&
 423                    (address64->address != (u64) address32)) {
 424                        ACPI_ERROR((AE_INFO,
 425                                    "32/64X address mismatch in %s: 0x%8.8X/0x%8.8X%8.8X, using 32",
 426                                    fadt_info_table[i].name, address32,
 427                                    ACPI_FORMAT_UINT64(address64->address)));
 428                }
 429
 430                /* Always use 32-bit address if it is valid (non-null) */
 431
 432                if (address32) {
 433                        /*
 434                         * Copy the 32-bit address to the 64-bit GAS structure. The
 435                         * Space ID is always I/O for 32-bit legacy address fields
 436                        */
 437                        acpi_tb_init_generic_address(address64,
 438                                                     ACPI_ADR_SPACE_SYSTEM_IO,
 439                                                     *ACPI_ADD_PTR(u8,
 440                                                                   &acpi_gbl_FADT,
 441                                                                   fadt_info_table
 442                                                                   [i].length),
 443                                                     (u64) address32);
 444                }
 445        }
 446}
 447
 448/*******************************************************************************
 449 *
 450 * FUNCTION:    acpi_tb_validate_fadt
 451 *
 452 * PARAMETERS:  Table           - Pointer to the FADT to be validated
 453 *
 454 * RETURN:      None
 455 *
 456 * DESCRIPTION: Validate various important fields within the FADT. If a problem
 457 *              is found, issue a message, but no status is returned.
 458 *              Used by both the table manager and the disassembler.
 459 *
 460 * Possible additional checks:
 461 * (acpi_gbl_FADT.pm1_event_length >= 4)
 462 * (acpi_gbl_FADT.pm1_control_length >= 2)
 463 * (acpi_gbl_FADT.pm_timer_length >= 4)
 464 * Gpe block lengths must be multiple of 2
 465 *
 466 ******************************************************************************/
 467
 468static void acpi_tb_validate_fadt(void)
 469{
 470        char *name;
 471        struct acpi_generic_address *address64;
 472        u8 length;
 473        u32 i;
 474
 475        /*
 476         * Check for FACS and DSDT address mismatches. An address mismatch between
 477         * the 32-bit and 64-bit address fields (FIRMWARE_CTRL/X_FIRMWARE_CTRL and
 478         * DSDT/X_DSDT) would indicate the presence of two FACS or two DSDT tables.
 479         */
 480        if (acpi_gbl_FADT.facs &&
 481            (acpi_gbl_FADT.Xfacs != (u64) acpi_gbl_FADT.facs)) {
 482                ACPI_WARNING((AE_INFO,
 483                              "32/64X FACS address mismatch in FADT - "
 484                              "0x%8.8X/0x%8.8X%8.8X, using 32",
 485                              acpi_gbl_FADT.facs,
 486                              ACPI_FORMAT_UINT64(acpi_gbl_FADT.Xfacs)));
 487
 488                acpi_gbl_FADT.Xfacs = (u64) acpi_gbl_FADT.facs;
 489        }
 490
 491        if (acpi_gbl_FADT.dsdt &&
 492            (acpi_gbl_FADT.Xdsdt != (u64) acpi_gbl_FADT.dsdt)) {
 493                ACPI_WARNING((AE_INFO,
 494                              "32/64X DSDT address mismatch in FADT - "
 495                              "0x%8.8X/0x%8.8X%8.8X, using 32",
 496                              acpi_gbl_FADT.dsdt,
 497                              ACPI_FORMAT_UINT64(acpi_gbl_FADT.Xdsdt)));
 498
 499                acpi_gbl_FADT.Xdsdt = (u64) acpi_gbl_FADT.dsdt;
 500        }
 501
 502        /* Examine all of the 64-bit extended address fields (X fields) */
 503
 504        for (i = 0; i < ACPI_FADT_INFO_ENTRIES; i++) {
 505                /*
 506                 * Generate pointer to the 64-bit address, get the register
 507                 * length (width) and the register name
 508                 */
 509                address64 = ACPI_ADD_PTR(struct acpi_generic_address,
 510                                         &acpi_gbl_FADT,
 511                                         fadt_info_table[i].address64);
 512                length =
 513                    *ACPI_ADD_PTR(u8, &acpi_gbl_FADT,
 514                                  fadt_info_table[i].length);
 515                name = fadt_info_table[i].name;
 516
 517                /*
 518                 * For each extended field, check for length mismatch between the
 519                 * legacy length field and the corresponding 64-bit X length field.
 520                 */
 521                if (address64->address &&
 522                    (address64->bit_width != ACPI_MUL_8(length))) {
 523                        ACPI_WARNING((AE_INFO,
 524                                      "32/64X length mismatch in %s: %u/%u",
 525                                      name, ACPI_MUL_8(length),
 526                                      address64->bit_width));
 527                }
 528
 529                if (fadt_info_table[i].type & ACPI_FADT_REQUIRED) {
 530                        /*
 531                         * Field is required (Pm1a_event, Pm1a_control, pm_timer).
 532                         * Both the address and length must be non-zero.
 533                         */
 534                        if (!address64->address || !length) {
 535                                ACPI_ERROR((AE_INFO,
 536                                            "Required field %s has zero address and/or length:"
 537                                            " 0x%8.8X%8.8X/0x%X",
 538                                            name,
 539                                            ACPI_FORMAT_UINT64(address64->
 540                                                               address),
 541                                            length));
 542                        }
 543                } else if (fadt_info_table[i].type & ACPI_FADT_SEPARATE_LENGTH) {
 544                        /*
 545                         * Field is optional (PM2Control, GPE0, GPE1) AND has its own
 546                         * length field. If present, both the address and length must
 547                         * be valid.
 548                         */
 549                        if ((address64->address && !length) ||
 550                            (!address64->address && length)) {
 551                                ACPI_WARNING((AE_INFO,
 552                                              "Optional field %s has zero address or length: "
 553                                              "0x%8.8X%8.8X/0x%X",
 554                                              name,
 555                                              ACPI_FORMAT_UINT64(address64->
 556                                                                 address),
 557                                              length));
 558                        }
 559                }
 560        }
 561}
 562
 563/*******************************************************************************
 564 *
 565 * FUNCTION:    acpi_tb_setup_fadt_registers
 566 *
 567 * PARAMETERS:  None, uses acpi_gbl_FADT.
 568 *
 569 * RETURN:      None
 570 *
 571 * DESCRIPTION: Initialize global ACPI PM1 register definitions. Optionally,
 572 *              force FADT register definitions to their default lengths.
 573 *
 574 ******************************************************************************/
 575
 576static void acpi_tb_setup_fadt_registers(void)
 577{
 578        struct acpi_generic_address *target64;
 579        struct acpi_generic_address *source64;
 580        u8 pm1_register_byte_width;
 581        u32 i;
 582
 583        /*
 584         * Optionally check all register lengths against the default values and
 585         * update them if they are incorrect.
 586         */
 587        if (acpi_gbl_use_default_register_widths) {
 588                for (i = 0; i < ACPI_FADT_INFO_ENTRIES; i++) {
 589                        target64 =
 590                            ACPI_ADD_PTR(struct acpi_generic_address,
 591                                         &acpi_gbl_FADT,
 592                                         fadt_info_table[i].address64);
 593
 594                        /*
 595                         * If a valid register (Address != 0) and the (default_length > 0)
 596                         * (Not a GPE register), then check the width against the default.
 597                         */
 598                        if ((target64->address) &&
 599                            (fadt_info_table[i].default_length > 0) &&
 600                            (fadt_info_table[i].default_length !=
 601                             target64->bit_width)) {
 602                                ACPI_WARNING((AE_INFO,
 603                                              "Invalid length for %s: %u, using default %u",
 604                                              fadt_info_table[i].name,
 605                                              target64->bit_width,
 606                                              fadt_info_table[i].
 607                                              default_length));
 608
 609                                /* Incorrect size, set width to the default */
 610
 611                                target64->bit_width =
 612                                    fadt_info_table[i].default_length;
 613                        }
 614                }
 615        }
 616
 617        /*
 618         * Get the length of the individual PM1 registers (enable and status).
 619         * Each register is defined to be (event block length / 2). Extra divide
 620         * by 8 converts bits to bytes.
 621         */
 622        pm1_register_byte_width = (u8)
 623            ACPI_DIV_16(acpi_gbl_FADT.xpm1a_event_block.bit_width);
 624
 625        /*
 626         * Calculate separate GAS structs for the PM1x (A/B) Status and Enable
 627         * registers. These addresses do not appear (directly) in the FADT, so it
 628         * is useful to pre-calculate them from the PM1 Event Block definitions.
 629         *
 630         * The PM event blocks are split into two register blocks, first is the
 631         * PM Status Register block, followed immediately by the PM Enable
 632         * Register block. Each is of length (pm1_event_length/2)
 633         *
 634         * Note: The PM1A event block is required by the ACPI specification.
 635         * However, the PM1B event block is optional and is rarely, if ever,
 636         * used.
 637         */
 638
 639        for (i = 0; i < ACPI_FADT_PM_INFO_ENTRIES; i++) {
 640                source64 =
 641                    ACPI_ADD_PTR(struct acpi_generic_address, &acpi_gbl_FADT,
 642                                 fadt_pm_info_table[i].source);
 643
 644                if (source64->address) {
 645                        acpi_tb_init_generic_address(fadt_pm_info_table[i].
 646                                                     target, source64->space_id,
 647                                                     pm1_register_byte_width,
 648                                                     source64->address +
 649                                                     (fadt_pm_info_table[i].
 650                                                      register_num *
 651                                                      pm1_register_byte_width));
 652                }
 653        }
 654}
 655