drivers/acpi/acpica/hwregs.c

   1 /*******************************************************************************
   2  *
   3  * Module Name: hwregs - Read/write access functions for the various ACPI
   4  *                       control and status registers.
   5  *
   6  ******************************************************************************/
   7
   8 /*
   9  * Copyright (C) 2000 - 2017, Intel Corp.
  10  * All rights reserved.
  11  *
  12  * Redistribution and use in source and binary forms, with or without
  13  * modification, are permitted provided that the following conditions
  14  * are met:
  15  * 1. Redistributions of source code must retain the above copyright
  16  *    notice, this list of conditions, and the following disclaimer,
  17  *    without modification.
  18  * 2. Redistributions in binary form must reproduce at minimum a disclaimer
  19  *    substantially similar to the "NO WARRANTY" disclaimer below
  20  *    ("Disclaimer") and any redistribution must be conditioned upon
  21  *    including a substantially similar Disclaimer requirement for further
  22  *    binary redistribution.
  23  * 3. Neither the names of the above-listed copyright holders nor the names
  24  *    of any contributors may be used to endorse or promote products derived
  25  *    from this software without specific prior written permission.
  26  *
  27  * Alternatively, this software may be distributed under the terms of the
  28  * GNU General Public License ("GPL") version 2 as published by the Free
  29  * Software Foundation.
  30  *
  31  * NO WARRANTY
  32  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  33  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  34  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
  35  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  36  * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  37  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  38  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  39  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  40  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
  41  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  42  * POSSIBILITY OF SUCH DAMAGES.
  43  */
  44
  45 #include <acpi/acpi.h>
  46 #include "accommon.h"
  47 #include "acevents.h"
  48
  49 #define _COMPONENT          ACPI_HARDWARE
  50 ACPI_MODULE_NAME("hwregs")
  51
  52 #if (!ACPI_REDUCED_HARDWARE)
  53 /* Local Prototypes */
  54 static u8
  55 acpi_hw_get_access_bit_width(u64 address,
  56                              struct acpi_generic_address *reg,
  57                              u8 max_bit_width);
  58
  59 static acpi_status
  60 acpi_hw_read_multiple(u32 *value,
  61                       struct acpi_generic_address *register_a,
  62                       struct acpi_generic_address *register_b);
  63
  64 static acpi_status
  65 acpi_hw_write_multiple(u32 value,
  66                        struct acpi_generic_address *register_a,
  67                        struct acpi_generic_address *register_b);
  68
  69 #endif                          /* !ACPI_REDUCED_HARDWARE */
  70
  71 /******************************************************************************
  72  *
  73  * FUNCTION:    acpi_hw_get_access_bit_width
  74  *
  75  * PARAMETERS:  address             - GAS register address
  76  *              reg                 - GAS register structure
  77  *              max_bit_width       - Max bit_width supported (32 or 64)
  78  *
  79  * RETURN:      Status
  80  *
  81  * DESCRIPTION: Obtain optimal access bit width
  82  *
  83  ******************************************************************************/
  84
  85 static u8
  86 acpi_hw_get_access_bit_width(u64 address,
  87                              struct acpi_generic_address *reg, u8 max_bit_width)
  88 {
  89         u8 access_bit_width;
  90
  91         /*
  92          * GAS format "register", used by FADT:
  93          *  1. Detected if bit_offset is 0 and bit_width is 8/16/32/64;
  94          *  2. access_size field is ignored and bit_width field is used for
  95          *     determining the boundary of the IO accesses.
  96          * GAS format "region", used by APEI registers:
  97          *  1. Detected if bit_offset is not 0 or bit_width is not 8/16/32/64;
  98          *  2. access_size field is used for determining the boundary of the
  99          *     IO accesses;
 100          *  3. bit_offset/bit_width fields are used to describe the "region".
 101          *
 102          * Note: This algorithm assumes that the "Address" fields should always
 103          *       contain aligned values.
 104          */
 105         if (!reg->bit_offset && reg->bit_width &&
 106             ACPI_IS_POWER_OF_TWO(reg->bit_width) &&
 107             ACPI_IS_ALIGNED(reg->bit_width, 8)) {
 108                 access_bit_width = reg->bit_width;
 109         } else if (reg->access_width) {
 110                 access_bit_width = ACPI_ACCESS_BIT_WIDTH(reg->access_width);
 111         } else {
 112                 access_bit_width =
 113                     ACPI_ROUND_UP_POWER_OF_TWO_8(reg->bit_offset +
 114                                                  reg->bit_width);
 115                 if (access_bit_width <= 8) {
 116                         access_bit_width = 8;
 117                 } else {
 118                         while (!ACPI_IS_ALIGNED(address, access_bit_width >> 3)) {
 119                                 access_bit_width >>= 1;
 120                         }
 121                 }
 122         }
 123
 124         /* Maximum IO port access bit width is 32 */
 125
 126         if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_IO) {
 127                 max_bit_width = 32;
 128         }
 129
 130         /*
 131          * Return access width according to the requested maximum access bit width,
 132          * as the caller should know the format of the register and may enforce
 133          * a 32-bit accesses.
 134          */
 135         if (access_bit_width < max_bit_width) {
 136                 return (access_bit_width);
 137         }
 138         return (max_bit_width);
 139 }
 140
 141 /******************************************************************************
 142  *
 143  * FUNCTION:    acpi_hw_validate_register
 144  *
 145  * PARAMETERS:  reg                 - GAS register structure
 146  *              max_bit_width       - Max bit_width supported (32 or 64)
 147  *              address             - Pointer to where the gas->address
 148  *                                    is returned
 149  *
 150  * RETURN:      Status
 151  *
 152  * DESCRIPTION: Validate the contents of a GAS register. Checks the GAS
 153  *              pointer, Address, space_id, bit_width, and bit_offset.
 154  *
 155  ******************************************************************************/
 156
 157 acpi_status
 158 acpi_hw_validate_register(struct acpi_generic_address *reg,
 159                           u8 max_bit_width, u64 *address)
 160 {
 161         u8 bit_width;
 162         u8 access_width;
 163
 164         /* Must have a valid pointer to a GAS structure */
 165
 166         if (!reg) {
 167                 return (AE_BAD_PARAMETER);
 168         }
 169
 170         /*
 171          * Copy the target address. This handles possible alignment issues.
 172          * Address must not be null. A null address also indicates an optional
 173          * ACPI register that is not supported, so no error message.
 174          */
 175         ACPI_MOVE_64_TO_64(address, &reg->address);
 176         if (!(*address)) {
 177                 return (AE_BAD_ADDRESS);
 178         }
 179
 180         /* Validate the space_ID */
 181
 182         if ((reg->space_id != ACPI_ADR_SPACE_SYSTEM_MEMORY) &&
 183             (reg->space_id != ACPI_ADR_SPACE_SYSTEM_IO)) {
 184                 ACPI_ERROR((AE_INFO,
 185                             "Unsupported address space: 0x%X", reg->space_id));
 186                 return (AE_SUPPORT);
 187         }
 188
 189         /* Validate the access_width */
 190
 191         if (reg->access_width > 4) {
 192                 ACPI_ERROR((AE_INFO,
 193                             "Unsupported register access width: 0x%X",
 194                             reg->access_width));
 195                 return (AE_SUPPORT);
 196         }
 197
 198         /* Validate the bit_width, convert access_width into number of bits */
 199
 200         access_width =
 201             acpi_hw_get_access_bit_width(*address, reg, max_bit_width);
 202         bit_width =
 203             ACPI_ROUND_UP(reg->bit_offset + reg->bit_width, access_width);
 204         if (max_bit_width < bit_width) {
 205                 ACPI_WARNING((AE_INFO,
 206                               "Requested bit width 0x%X is smaller than register bit width 0x%X",
 207                               max_bit_width, bit_width));
 208                 return (AE_SUPPORT);
 209         }
 210
 211         return (AE_OK);
 212 }
 213
 214 /******************************************************************************
 215  *
 216  * FUNCTION:    acpi_hw_read
 217  *
 218  * PARAMETERS:  value               - Where the value is returned
 219  *              reg                 - GAS register structure
 220  *
 221  * RETURN:      Status
 222  *
 223  * DESCRIPTION: Read from either memory or IO space. This is a 64-bit max
 224  *              version of acpi_read.
 225  *
 226  * LIMITATIONS: <These limitations also apply to acpi_hw_write>
 227  *      space_ID must be system_memory or system_IO.
 228  *
 229  ******************************************************************************/
 230
 231 acpi_status acpi_hw_read(u64 *value, struct acpi_generic_address *reg)
 232 {
 233         u64 address;
 234         u8 access_width;
 235         u32 bit_width;
 236         u8 bit_offset;
 237         u64 value64;
 238         u32 value32;
 239         u8 index;
 240         acpi_status status;
 241
 242         ACPI_FUNCTION_NAME(hw_read);
 243
 244         /* Validate contents of the GAS register */
 245
 246         status = acpi_hw_validate_register(reg, 64, &address);
 247         if (ACPI_FAILURE(status)) {
 248                 return (status);
 249         }
 250
 251         /*
 252          * Initialize entire 64-bit return value to zero, convert access_width
 253          * into number of bits based
 254          */
 255         *value = 0;
 256         access_width = acpi_hw_get_access_bit_width(address, reg, 64);
 257         bit_width = reg->bit_offset + reg->bit_width;
 258         bit_offset = reg->bit_offset;
 259
 260         /*
 261          * Two address spaces supported: Memory or IO. PCI_Config is
 262          * not supported here because the GAS structure is insufficient
 263          */
 264         index = 0;
 265         while (bit_width) {
 266                 if (bit_offset >= access_width) {
 267                         value64 = 0;
 268                         bit_offset -= access_width;
 269                 } else {
 270                         if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) {
 271                                 status =
 272                                     acpi_os_read_memory((acpi_physical_address)
 273                                                         address +
 274                                                         index *
 275                                                         ACPI_DIV_8
 276                                                         (access_width),
 277                                                         &value64, access_width);
 278                         } else {        /* ACPI_ADR_SPACE_SYSTEM_IO, validated earlier */
 279
 280                                 status = acpi_hw_read_port((acpi_io_address)
 281                                                            address +
 282                                                            index *
 283                                                            ACPI_DIV_8
 284                                                            (access_width),
 285                                                            &value32,
 286                                                            access_width);
 287                                 value64 = (u64)value32;
 288                         }
 289                 }
 290
 291                 /*
 292                  * Use offset style bit writes because "Index * AccessWidth" is
 293                  * ensured to be less than 64-bits by acpi_hw_validate_register().
 294                  */
 295                 ACPI_SET_BITS(value, index * access_width,
 296                               ACPI_MASK_BITS_ABOVE_64(access_width), value64);
 297
 298                 bit_width -=
 299                     bit_width > access_width ? access_width : bit_width;
 300                 index++;
 301         }
 302
 303         ACPI_DEBUG_PRINT((ACPI_DB_IO,
 304                           "Read:  %8.8X%8.8X width %2d from %8.8X%8.8X (%s)\n",
 305                           ACPI_FORMAT_UINT64(*value), access_width,
 306                           ACPI_FORMAT_UINT64(address),
 307                           acpi_ut_get_region_name(reg->space_id)));
 308
 309         return (status);
 310 }
 311
 312 /******************************************************************************
 313  *
 314  * FUNCTION:    acpi_hw_write
 315  *
 316  * PARAMETERS:  value               - Value to be written
 317  *              reg                 - GAS register structure
 318  *
 319  * RETURN:      Status
 320  *
 321  * DESCRIPTION: Write to either memory or IO space. This is a 64-bit max
 322  *              version of acpi_write.
 323  *
 324  ******************************************************************************/
 325
 326 acpi_status acpi_hw_write(u64 value, struct acpi_generic_address *reg)
 327 {
 328         u64 address;
 329         u8 access_width;
 330         u32 bit_width;
 331         u8 bit_offset;
 332         u64 value64;
 333         u8 index;
 334         acpi_status status;
 335
 336         ACPI_FUNCTION_NAME(hw_write);
 337
 338         /* Validate contents of the GAS register */
 339
 340         status = acpi_hw_validate_register(reg, 64, &address);
 341         if (ACPI_FAILURE(status)) {
 342                 return (status);
 343         }
 344
 345         /* Convert access_width into number of bits based */
 346
 347         access_width = acpi_hw_get_access_bit_width(address, reg, 64);
 348         bit_width = reg->bit_offset + reg->bit_width;
 349         bit_offset = reg->bit_offset;
 350
 351         /*
 352          * Two address spaces supported: Memory or IO. PCI_Config is
 353          * not supported here because the GAS structure is insufficient
 354          */
 355         index = 0;
 356         while (bit_width) {
 357                 /*
 358                  * Use offset style bit reads because "Index * AccessWidth" is
 359                  * ensured to be less than 64-bits by acpi_hw_validate_register().
 360                  */
 361                 value64 = ACPI_GET_BITS(&value, index * access_width,
 362                                         ACPI_MASK_BITS_ABOVE_64(access_width));
 363
 364                 if (bit_offset >= access_width) {
 365                         bit_offset -= access_width;
 366                 } else {
 367                         if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) {
 368                                 status =
 369                                     acpi_os_write_memory((acpi_physical_address)
 370                                                          address +
 371                                                          index *
 372                                                          ACPI_DIV_8
 373                                                          (access_width),
 374                                                          value64, access_width);
 375                         } else {        /* ACPI_ADR_SPACE_SYSTEM_IO, validated earlier */
 376
 377                                 status = acpi_hw_write_port((acpi_io_address)
 378                                                             address +
 379                                                             index *
 380                                                             ACPI_DIV_8
 381                                                             (access_width),
 382                                                             (u32)value64,
 383                                                             access_width);
 384                         }
 385                 }
 386
 387                 /*
 388                  * Index * access_width is ensured to be less than 32-bits by
 389                  * acpi_hw_validate_register().
 390                  */
 391                 bit_width -=
 392                     bit_width > access_width ? access_width : bit_width;
 393                 index++;
 394         }
 395
 396         ACPI_DEBUG_PRINT((ACPI_DB_IO,
 397                           "Wrote: %8.8X%8.8X width %2d   to %8.8X%8.8X (%s)\n",
 398                           ACPI_FORMAT_UINT64(value), access_width,
 399                           ACPI_FORMAT_UINT64(address),
 400                           acpi_ut_get_region_name(reg->space_id)));
 401
 402         return (status);
 403 }
 404
 405 #if (!ACPI_REDUCED_HARDWARE)
 406 /*******************************************************************************
 407  *
 408  * FUNCTION:    acpi_hw_clear_acpi_status
 409  *
 410  * PARAMETERS:  None
 411  *
 412  * RETURN:      Status
 413  *
 414  * DESCRIPTION: Clears all fixed and general purpose status bits
 415  *
 416  ******************************************************************************/
 417
 418 acpi_status acpi_hw_clear_acpi_status(void)
 419 {
 420         acpi_status status;
 421         acpi_cpu_flags lock_flags = 0;
 422
 423         ACPI_FUNCTION_TRACE(hw_clear_acpi_status);
 424
 425         ACPI_DEBUG_PRINT((ACPI_DB_IO, "About to write %04X to %8.8X%8.8X\n",
 426                           ACPI_BITMASK_ALL_FIXED_STATUS,
 427                           ACPI_FORMAT_UINT64(acpi_gbl_xpm1a_status.address)));
 428
 429         lock_flags = acpi_os_acquire_lock(acpi_gbl_hardware_lock);
 430
 431         /* Clear the fixed events in PM1 A/B */
 432
 433         status = acpi_hw_register_write(ACPI_REGISTER_PM1_STATUS,
 434                                         ACPI_BITMASK_ALL_FIXED_STATUS);
 435
 436         acpi_os_release_lock(acpi_gbl_hardware_lock, lock_flags);
 437
 438         if (ACPI_FAILURE(status)) {
 439                 goto exit;
 440         }
 441
 442         /* Clear the GPE Bits in all GPE registers in all GPE blocks */
 443
 444         status = acpi_ev_walk_gpe_list(acpi_hw_clear_gpe_block, NULL);
 445
 446 exit:
 447         return_ACPI_STATUS(status);
 448 }
 449
 450 /*******************************************************************************
 451  *
 452  * FUNCTION:    acpi_hw_get_bit_register_info
 453  *
 454  * PARAMETERS:  register_id         - Index of ACPI Register to access
 455  *
 456  * RETURN:      The bitmask to be used when accessing the register
 457  *
 458  * DESCRIPTION: Map register_id into a register bitmask.
 459  *
 460  ******************************************************************************/
 461
 462 struct acpi_bit_register_info *acpi_hw_get_bit_register_info(u32 register_id)
 463 {
 464         ACPI_FUNCTION_ENTRY();
 465
 466         if (register_id > ACPI_BITREG_MAX) {
 467                 ACPI_ERROR((AE_INFO, "Invalid BitRegister ID: 0x%X",
 468                             register_id));
 469                 return (NULL);
 470         }
 471
 472         return (&acpi_gbl_bit_register_info[register_id]);
 473 }
 474
 475 /******************************************************************************
 476  *
 477  * FUNCTION:    acpi_hw_write_pm1_control
 478  *
 479  * PARAMETERS:  pm1a_control        - Value to be written to PM1A control
 480  *              pm1b_control        - Value to be written to PM1B control
 481  *
 482  * RETURN:      Status
 483  *
 484  * DESCRIPTION: Write the PM1 A/B control registers. These registers are
 485  *              different than than the PM1 A/B status and enable registers
 486  *              in that different values can be written to the A/B registers.
 487  *              Most notably, the SLP_TYP bits can be different, as per the
 488  *              values returned from the _Sx predefined methods.
 489  *
 490  ******************************************************************************/
 491
 492 acpi_status acpi_hw_write_pm1_control(u32 pm1a_control, u32 pm1b_control)
 493 {
 494         acpi_status status;
 495
 496         ACPI_FUNCTION_TRACE(hw_write_pm1_control);
 497
 498         status =
 499             acpi_hw_write(pm1a_control, &acpi_gbl_FADT.xpm1a_control_block);
 500         if (ACPI_FAILURE(status)) {
 501                 return_ACPI_STATUS(status);
 502         }
 503
 504         if (acpi_gbl_FADT.xpm1b_control_block.address) {
 505                 status =
 506                     acpi_hw_write(pm1b_control,
 507                                   &acpi_gbl_FADT.xpm1b_control_block);
 508         }
 509         return_ACPI_STATUS(status);
 510 }
 511
 512 /******************************************************************************
 513  *
 514  * FUNCTION:    acpi_hw_register_read
 515  *
 516  * PARAMETERS:  register_id         - ACPI Register ID
 517  *              return_value        - Where the register value is returned
 518  *
 519  * RETURN:      Status and the value read.
 520  *
 521  * DESCRIPTION: Read from the specified ACPI register
 522  *
 523  ******************************************************************************/
 524 acpi_status acpi_hw_register_read(u32 register_id, u32 *return_value)
 525 {
 526         u32 value = 0;
 527         u64 value64;
 528         acpi_status status;
 529
 530         ACPI_FUNCTION_TRACE(hw_register_read);
 531
 532         switch (register_id) {
 533         case ACPI_REGISTER_PM1_STATUS:  /* PM1 A/B: 16-bit access each */
 534
 535                 status = acpi_hw_read_multiple(&value,
 536                                                &acpi_gbl_xpm1a_status,
 537                                                &acpi_gbl_xpm1b_status);
 538                 break;
 539
 540         case ACPI_REGISTER_PM1_ENABLE:  /* PM1 A/B: 16-bit access each */
 541
 542                 status = acpi_hw_read_multiple(&value,
 543                                                &acpi_gbl_xpm1a_enable,
 544                                                &acpi_gbl_xpm1b_enable);
 545                 break;
 546
 547         case ACPI_REGISTER_PM1_CONTROL: /* PM1 A/B: 16-bit access each */
 548
 549                 status = acpi_hw_read_multiple(&value,
 550                                                &acpi_gbl_FADT.
 551                                                xpm1a_control_block,
 552                                                &acpi_gbl_FADT.
 553                                                xpm1b_control_block);
 554
 555                 /*
 556                  * Zero the write-only bits. From the ACPI specification, "Hardware
 557                  * Write-Only Bits": "Upon reads to registers with write-only bits,
 558                  * software masks out all write-only bits."
 559                  */
 560                 value &= ~ACPI_PM1_CONTROL_WRITEONLY_BITS;
 561                 break;
 562
 563         case ACPI_REGISTER_PM2_CONTROL: /* 8-bit access */
 564
 565                 status =
 566                     acpi_hw_read(&value64, &acpi_gbl_FADT.xpm2_control_block);
 567                 value = (u32)value64;
 568                 break;
 569
 570         case ACPI_REGISTER_PM_TIMER:    /* 32-bit access */
 571
 572                 status = acpi_hw_read(&value64, &acpi_gbl_FADT.xpm_timer_block);
 573                 value = (u32)value64;
 574                 break;
 575
 576         case ACPI_REGISTER_SMI_COMMAND_BLOCK:   /* 8-bit access */
 577
 578                 status =
 579                     acpi_hw_read_port(acpi_gbl_FADT.smi_command, &value, 8);
 580                 break;
 581
 582         default:
 583
 584                 ACPI_ERROR((AE_INFO, "Unknown Register ID: 0x%X", register_id));
 585                 status = AE_BAD_PARAMETER;
 586                 break;
 587         }
 588
 589         if (ACPI_SUCCESS(status)) {
 590                 *return_value = (u32)value;
 591         }
 592
 593         return_ACPI_STATUS(status);
 594 }
 595
 596 /******************************************************************************
 597  *
 598  * FUNCTION:    acpi_hw_register_write
 599  *
 600  * PARAMETERS:  register_id         - ACPI Register ID
 601  *              value               - The value to write
 602  *
 603  * RETURN:      Status
 604  *
 605  * DESCRIPTION: Write to the specified ACPI register
 606  *
 607  * NOTE: In accordance with the ACPI specification, this function automatically
 608  * preserves the value of the following bits, meaning that these bits cannot be
 609  * changed via this interface:
 610  *
 611  * PM1_CONTROL[0] = SCI_EN
 612  * PM1_CONTROL[9]
 613  * PM1_STATUS[11]
 614  *
 615  * ACPI References:
 616  * 1) Hardware Ignored Bits: When software writes to a register with ignored
 617  *      bit fields, it preserves the ignored bit fields
 618  * 2) SCI_EN: OSPM always preserves this bit position
 619  *
 620  ******************************************************************************/
 621
 622 acpi_status acpi_hw_register_write(u32 register_id, u32 value)
 623 {
 624         acpi_status status;
 625         u32 read_value;
 626         u64 read_value64;
 627
 628         ACPI_FUNCTION_TRACE(hw_register_write);
 629
 630         switch (register_id) {
 631         case ACPI_REGISTER_PM1_STATUS:  /* PM1 A/B: 16-bit access each */
 632                 /*
 633                  * Handle the "ignored" bit in PM1 Status. According to the ACPI
 634                  * specification, ignored bits are to be preserved when writing.
 635                  * Normally, this would mean a read/modify/write sequence. However,
 636                  * preserving a bit in the status register is different. Writing a
 637                  * one clears the status, and writing a zero preserves the status.
 638                  * Therefore, we must always write zero to the ignored bit.
 639                  *
 640                  * This behavior is clarified in the ACPI 4.0 specification.
 641                  */
 642                 value &= ~ACPI_PM1_STATUS_PRESERVED_BITS;
 643
 644                 status = acpi_hw_write_multiple(value,
 645                                                 &acpi_gbl_xpm1a_status,
 646                                                 &acpi_gbl_xpm1b_status);
 647                 break;
 648
 649         case ACPI_REGISTER_PM1_ENABLE:  /* PM1 A/B: 16-bit access each */
 650
 651                 status = acpi_hw_write_multiple(value,
 652                                                 &acpi_gbl_xpm1a_enable,
 653                                                 &acpi_gbl_xpm1b_enable);
 654                 break;
 655
 656         case ACPI_REGISTER_PM1_CONTROL: /* PM1 A/B: 16-bit access each */
 657                 /*
 658                  * Perform a read first to preserve certain bits (per ACPI spec)
 659                  * Note: This includes SCI_EN, we never want to change this bit
 660                  */
 661                 status = acpi_hw_read_multiple(&read_value,
 662                                                &acpi_gbl_FADT.
 663                                                xpm1a_control_block,
 664                                                &acpi_gbl_FADT.
 665                                                xpm1b_control_block);
 666                 if (ACPI_FAILURE(status)) {
 667                         goto exit;
 668                 }
 669
 670                 /* Insert the bits to be preserved */
 671
 672                 ACPI_INSERT_BITS(value, ACPI_PM1_CONTROL_PRESERVED_BITS,
 673                                  read_value);
 674
 675                 /* Now we can write the data */
 676
 677                 status = acpi_hw_write_multiple(value,
 678                                                 &acpi_gbl_FADT.
 679                                                 xpm1a_control_block,
 680                                                 &acpi_gbl_FADT.
 681                                                 xpm1b_control_block);
 682                 break;
 683
 684         case ACPI_REGISTER_PM2_CONTROL: /* 8-bit access */
 685                 /*
 686                  * For control registers, all reserved bits must be preserved,
 687                  * as per the ACPI spec.
 688                  */
 689                 status =
 690                     acpi_hw_read(&read_value64,
 691                                  &acpi_gbl_FADT.xpm2_control_block);
 692                 if (ACPI_FAILURE(status)) {
 693                         goto exit;
 694                 }
 695                 read_value = (u32)read_value64;
 696
 697                 /* Insert the bits to be preserved */
 698
 699                 ACPI_INSERT_BITS(value, ACPI_PM2_CONTROL_PRESERVED_BITS,
 700                                  read_value);
 701
 702                 status =
 703                     acpi_hw_write(value, &acpi_gbl_FADT.xpm2_control_block);
 704                 break;
 705
 706         case ACPI_REGISTER_PM_TIMER:    /* 32-bit access */
 707
 708                 status = acpi_hw_write(value, &acpi_gbl_FADT.xpm_timer_block);
 709                 break;
 710
 711         case ACPI_REGISTER_SMI_COMMAND_BLOCK:   /* 8-bit access */
 712
 713                 /* SMI_CMD is currently always in IO space */
 714
 715                 status =
 716                     acpi_hw_write_port(acpi_gbl_FADT.smi_command, value, 8);
 717                 break;
 718
 719         default:
 720
 721                 ACPI_ERROR((AE_INFO, "Unknown Register ID: 0x%X", register_id));
 722                 status = AE_BAD_PARAMETER;
 723                 break;
 724         }
 725
 726 exit:
 727         return_ACPI_STATUS(status);
 728 }
 729
 730 /******************************************************************************
 731  *
 732  * FUNCTION:    acpi_hw_read_multiple
 733  *
 734  * PARAMETERS:  value               - Where the register value is returned
 735  *              register_a           - First ACPI register (required)
 736  *              register_b           - Second ACPI register (optional)
 737  *
 738  * RETURN:      Status
 739  *
 740  * DESCRIPTION: Read from the specified two-part ACPI register (such as PM1 A/B)
 741  *
 742  ******************************************************************************/
 743
 744 static acpi_status
 745 acpi_hw_read_multiple(u32 *value,
 746                       struct acpi_generic_address *register_a,
 747                       struct acpi_generic_address *register_b)
 748 {
 749         u32 value_a = 0;
 750         u32 value_b = 0;
 751         u64 value64;
 752         acpi_status status;
 753
 754         /* The first register is always required */
 755
 756         status = acpi_hw_read(&value64, register_a);
 757         if (ACPI_FAILURE(status)) {
 758                 return (status);
 759         }
 760         value_a = (u32)value64;
 761
 762         /* Second register is optional */
 763
 764         if (register_b->address) {
 765                 status = acpi_hw_read(&value64, register_b);
 766                 if (ACPI_FAILURE(status)) {
 767                         return (status);
 768                 }
 769                 value_b = (u32)value64;
 770         }
 771
 772         /*
 773          * OR the two return values together. No shifting or masking is necessary,
 774          * because of how the PM1 registers are defined in the ACPI specification:
 775          *
 776          * "Although the bits can be split between the two register blocks (each
 777          * register block has a unique pointer within the FADT), the bit positions
 778          * are maintained. The register block with unimplemented bits (that is,
 779          * those implemented in the other register block) always returns zeros,
 780          * and writes have no side effects"
 781          */
 782         *value = (value_a | value_b);
 783         return (AE_OK);
 784 }
 785
 786 /******************************************************************************
 787  *
 788  * FUNCTION:    acpi_hw_write_multiple
 789  *
 790  * PARAMETERS:  value               - The value to write
 791  *              register_a           - First ACPI register (required)
 792  *              register_b           - Second ACPI register (optional)
 793  *
 794  * RETURN:      Status
 795  *
 796  * DESCRIPTION: Write to the specified two-part ACPI register (such as PM1 A/B)
 797  *
 798  ******************************************************************************/
 799
 800 static acpi_status
 801 acpi_hw_write_multiple(u32 value,
 802                        struct acpi_generic_address *register_a,
 803                        struct acpi_generic_address *register_b)
 804 {
 805         acpi_status status;
 806
 807         /* The first register is always required */
 808
 809         status = acpi_hw_write(value, register_a);
 810         if (ACPI_FAILURE(status)) {
 811                 return (status);
 812         }
 813
 814         /*
 815          * Second register is optional
 816          *
 817          * No bit shifting or clearing is necessary, because of how the PM1
 818          * registers are defined in the ACPI specification:
 819          *
 820          * "Although the bits can be split between the two register blocks (each
 821          * register block has a unique pointer within the FADT), the bit positions
 822          * are maintained. The register block with unimplemented bits (that is,
 823          * those implemented in the other register block) always returns zeros,
 824          * and writes have no side effects"
 825          */
 826         if (register_b->address) {
 827                 status = acpi_hw_write(value, register_b);
 828         }
 829
 830         return (status);
 831 }
 832
 833 #endif                          /* !ACPI_REDUCED_HARDWARE */