drivers/acpi/acpica/tbfadt.c

   1 /******************************************************************************
   2  *
   3  * Module Name: tbfadt   - FADT table utilities
   4  *
   5  *****************************************************************************/
   6
   7 /*
   8  * Copyright (C) 2000 - 2008, 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
  49 ACPI_MODULE_NAME("tbfadt")
  50
  51 /* Local prototypes */
  52 static inline void
  53 acpi_tb_init_generic_address(struct acpi_generic_address *generic_address,
  54                              u8 space_id, u8 byte_width, u64 address);
  55
  56 static void acpi_tb_convert_fadt(void);
  57
  58 static void acpi_tb_validate_fadt(void);
  59
  60 static void acpi_tb_setup_fadt_registers(void);
  61
  62 /* Table for conversion of FADT to common internal format and FADT validation */
  63
  64 typedef 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
  77 static 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
 140 typedef 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
 147 static 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
 184 static inline void
 185 acpi_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
 216 void 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
 276 void 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 0x%X to 0x%X",
 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
 347 static 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: %8.8X/%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
 468 static 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                               "%8.8X/%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                               "%8.8X/%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: %d/%d",
 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                                             " %8.8X%8.8X/%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                                               "%8.8X%8.8X/%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
 576 static 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: %d, using default %d",
 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 }