Training courses

Kernel and Embedded Linux

Bootlin training courses

Embedded Linux, kernel,
Yocto Project, Buildroot, real-time,
graphics, boot time, debugging...

Bootlin logo

Elixir Cross Referencer

   1
   2
   3
   4
   5
   6
   7
   8
   9
  10
  11
  12
  13
  14
  15
  16
  17
  18
  19
  20
  21
  22
  23
  24
  25
  26
  27
  28
  29
  30
  31
  32
  33
  34
  35
  36
  37
  38
  39
  40
  41
  42
  43
  44
  45
  46
  47
  48
  49
  50
  51
  52
  53
  54
  55
  56
  57
  58
  59
  60
  61
  62
  63
  64
  65
  66
  67
  68
  69
  70
  71
  72
  73
  74
  75
  76
  77
  78
  79
  80
  81
  82
  83
  84
  85
  86
  87
  88
  89
  90
  91
  92
  93
  94
  95
  96
  97
  98
  99
 100
 101
 102
 103
 104
 105
 106
 107
 108
 109
 110
 111
 112
 113
 114
 115
 116
 117
 118
 119
 120
 121
 122
 123
 124
 125
 126
 127
 128
 129
 130
 131
 132
 133
 134
 135
 136
 137
 138
 139
 140
 141
 142
 143
 144
 145
 146
 147
 148
 149
 150
 151
 152
 153
 154
 155
 156
 157
 158
 159
 160
 161
 162
 163
 164
 165
 166
 167
 168
 169
 170
 171
 172
 173
 174
 175
 176
 177
 178
 179
 180
 181
 182
 183
 184
 185
 186
 187
 188
 189
 190
 191
 192
 193
 194
 195
 196
 197
 198
 199
 200
 201
 202
 203
 204
 205
 206
 207
 208
 209
 210
 211
 212
 213
 214
 215
 216
 217
 218
 219
 220
 221
 222
 223
 224
 225
 226
 227
 228
 229
 230
 231
 232
 233
 234
 235
 236
 237
 238
 239
 240
 241
 242
 243
 244
 245
 246
 247
 248
 249
 250
 251
 252
 253
 254
 255
 256
 257
 258
 259
 260
 261
 262
 263
 264
 265
 266
 267
 268
 269
 270
 271
 272
 273
 274
 275
 276
 277
 278
 279
 280
 281
 282
 283
 284
 285
 286
 287
 288
 289
 290
 291
 292
 293
 294
 295
 296
 297
 298
 299
 300
 301
 302
 303
 304
 305
 306
 307
 308
 309
 310
 311
 312
 313
 314
 315
 316
 317
 318
 319
 320
 321
 322
 323
 324
 325
 326
 327
 328
 329
 330
 331
 332
 333
 334
 335
 336
 337
 338
 339
 340
 341
 342
 343
 344
 345
 346
 347
 348
 349
 350
 351
 352
 353
 354
 355
 356
 357
 358
 359
 360
 361
 362
 363
 364
 365
 366
 367
 368
 369
 370
 371
 372
 373
 374
 375
 376
 377
 378
 379
 380
 381
 382
 383
 384
 385
 386
 387
 388
 389
 390
 391
 392
 393
 394
 395
 396
 397
 398
 399
 400
 401
 402
 403
 404
 405
 406
 407
 408
 409
 410
 411
 412
 413
 414
 415
 416
 417
 418
 419
 420
 421
 422
 423
 424
 425
 426
 427
 428
 429
 430
 431
 432
 433
 434
 435
 436
 437
 438
 439
 440
 441
 442
 443
 444
 445
 446
 447
 448
 449
 450
 451
 452
 453
 454
 455
 456
 457
 458
 459
 460
 461
 462
 463
 464
 465
 466
 467
 468
 469
 470
 471
 472
 473
 474
 475
 476
 477
 478
 479
 480
 481
 482
 483
 484
 485
 486
 487
 488
 489
 490
 491
 492
 493
 494
 495
 496
 497
 498
 499
 500
 501
 502
 503
 504
 505
 506
 507
 508
 509
 510
 511
 512
 513
 514
 515
 516
 517
 518
 519
 520
 521
 522
 523
 524
 525
 526
 527
 528
 529
 530
 531
 532
 533
 534
 535
 536
 537
 538
 539
 540
 541
 542
 543
 544
 545
 546
 547
 548
 549
 550
 551
 552
 553
 554
 555
 556
 557
 558
 559
 560
 561
 562
 563
 564
 565
 566
 567
 568
 569
 570
 571
 572
 573
 574
 575
 576
 577
 578
 579
 580
 581
 582
 583
 584
 585
 586
 587
 588
 589
 590
 591
 592
 593
 594
 595
 596
 597
 598
 599
 600
 601
 602
 603
 604
 605
 606
 607
 608
 609
 610
 611
 612
 613
 614
 615
 616
 617
 618
 619
 620
 621
 622
 623
 624
 625
 626
 627
 628
 629
 630
 631
 632
 633
 634
 635
 636
 637
 638
 639
 640
 641
 642
 643
 644
 645
 646
 647
 648
 649
 650
 651
 652
 653
 654
 655
 656
 657
 658
 659
 660
 661
 662
 663
 664
 665
 666
 667
 668
 669
 670
 671
 672
 673
 674
 675
 676
 677
 678
 679
 680
 681
 682
 683
 684
 685
 686
 687
 688
 689
 690
 691
 692
 693
 694
 695
 696
 697
 698
 699
 700
 701
 702
 703
 704
 705
 706
 707
 708
 709
 710
 711
 712
 713
 714
 715
 716
 717
 718
 719
 720
 721
 722
 723
 724
 725
 726
 727
 728
 729
 730
 731
 732
 733
 734
 735
 736
 737
 738
 739
 740
 741
 742
 743
 744
 745
 746
 747
 748
 749
 750
 751
 752
 753
 754
 755
 756
 757
 758
 759
 760
 761
 762
 763
 764
 765
 766
 767
 768
 769
 770
 771
 772
 773
 774
 775
 776
 777
 778
 779
 780
 781
 782
 783
 784
 785
 786
 787
 788
 789
 790
 791
 792
 793
 794
 795
 796
 797
 798
 799
 800
 801
 802
 803
 804
 805
 806
 807
 808
 809
 810
 811
 812
 813
 814
 815
 816
 817
 818
 819
 820
 821
 822
 823
 824
 825
 826
 827
 828
 829
 830
 831
 832
 833
 834
 835
 836
 837
 838
 839
 840
 841
 842
 843
 844
 845
 846
 847
 848
 849
 850
 851
 852
 853
 854
 855
 856
 857
 858
 859
 860
 861
 862
 863
 864
 865
 866
 867
 868
 869
 870
 871
 872
 873
 874
 875
 876
 877
 878
 879
 880
 881
 882
 883
 884
 885
 886
 887
 888
 889
 890
 891
 892
 893
 894
 895
 896
 897
 898
 899
 900
 901
 902
 903
 904
 905
 906
 907
 908
 909
 910
 911
 912
 913
 914
 915
 916
 917
 918
 919
 920
 921
 922
 923
 924
 925
 926
 927
 928
 929
 930
 931
 932
 933
 934
 935
 936
 937
 938
 939
 940
 941
 942
 943
 944
 945
 946
 947
 948
 949
 950
 951
 952
 953
 954
 955
 956
 957
 958
 959
 960
 961
 962
 963
 964
 965
 966
 967
 968
 969
 970
 971
 972
 973
 974
 975
 976
 977
 978
 979
 980
 981
 982
 983
 984
 985
 986
 987
 988
 989
 990
 991
 992
 993
 994
 995
 996
 997
 998
 999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
/*******************************************************************************
 *
 * Module Name: hwregs - Read/write access functions for the various ACPI
 *                       control and status registers.
 *
 ******************************************************************************/

/******************************************************************************
 *
 * 1. Copyright Notice
 *
 * Some or all of this work - Copyright (c) 1999 - 2019, Intel Corp.
 * All rights reserved.
 *
 * 2. License
 *
 * 2.1. This is your license from Intel Corp. under its intellectual property
 * rights. You may have additional license terms from the party that provided
 * you this software, covering your right to use that party's intellectual
 * property rights.
 *
 * 2.2. Intel grants, free of charge, to any person ("Licensee") obtaining a
 * copy of the source code appearing in this file ("Covered Code") an
 * irrevocable, perpetual, worldwide license under Intel's copyrights in the
 * base code distributed originally by Intel ("Original Intel Code") to copy,
 * make derivatives, distribute, use and display any portion of the Covered
 * Code in any form, with the right to sublicense such rights; and
 *
 * 2.3. Intel grants Licensee a non-exclusive and non-transferable patent
 * license (with the right to sublicense), under only those claims of Intel
 * patents that are infringed by the Original Intel Code, to make, use, sell,
 * offer to sell, and import the Covered Code and derivative works thereof
 * solely to the minimum extent necessary to exercise the above copyright
 * license, and in no event shall the patent license extend to any additions
 * to or modifications of the Original Intel Code. No other license or right
 * is granted directly or by implication, estoppel or otherwise;
 *
 * The above copyright and patent license is granted only if the following
 * conditions are met:
 *
 * 3. Conditions
 *
 * 3.1. Redistribution of Source with Rights to Further Distribute Source.
 * Redistribution of source code of any substantial portion of the Covered
 * Code or modification with rights to further distribute source must include
 * the above Copyright Notice, the above License, this list of Conditions,
 * and the following Disclaimer and Export Compliance provision. In addition,
 * Licensee must cause all Covered Code to which Licensee contributes to
 * contain a file documenting the changes Licensee made to create that Covered
 * Code and the date of any change. Licensee must include in that file the
 * documentation of any changes made by any predecessor Licensee. Licensee
 * must include a prominent statement that the modification is derived,
 * directly or indirectly, from Original Intel Code.
 *
 * 3.2. Redistribution of Source with no Rights to Further Distribute Source.
 * Redistribution of source code of any substantial portion of the Covered
 * Code or modification without rights to further distribute source must
 * include the following Disclaimer and Export Compliance provision in the
 * documentation and/or other materials provided with distribution. In
 * addition, Licensee may not authorize further sublicense of source of any
 * portion of the Covered Code, and must include terms to the effect that the
 * license from Licensee to its licensee is limited to the intellectual
 * property embodied in the software Licensee provides to its licensee, and
 * not to intellectual property embodied in modifications its licensee may
 * make.
 *
 * 3.3. Redistribution of Executable. Redistribution in executable form of any
 * substantial portion of the Covered Code or modification must reproduce the
 * above Copyright Notice, and the following Disclaimer and Export Compliance
 * provision in the documentation and/or other materials provided with the
 * distribution.
 *
 * 3.4. Intel retains all right, title, and interest in and to the Original
 * Intel Code.
 *
 * 3.5. Neither the name Intel nor any other trademark owned or controlled by
 * Intel shall be used in advertising or otherwise to promote the sale, use or
 * other dealings in products derived from or relating to the Covered Code
 * without prior written authorization from Intel.
 *
 * 4. Disclaimer and Export Compliance
 *
 * 4.1. INTEL MAKES NO WARRANTY OF ANY KIND REGARDING ANY SOFTWARE PROVIDED
 * HERE. ANY SOFTWARE ORIGINATING FROM INTEL OR DERIVED FROM INTEL SOFTWARE
 * IS PROVIDED "AS IS," AND INTEL WILL NOT PROVIDE ANY SUPPORT, ASSISTANCE,
 * INSTALLATION, TRAINING OR OTHER SERVICES. INTEL WILL NOT PROVIDE ANY
 * UPDATES, ENHANCEMENTS OR EXTENSIONS. INTEL SPECIFICALLY DISCLAIMS ANY
 * IMPLIED WARRANTIES OF MERCHANTABILITY, NONINFRINGEMENT AND FITNESS FOR A
 * PARTICULAR PURPOSE.
 *
 * 4.2. IN NO EVENT SHALL INTEL HAVE ANY LIABILITY TO LICENSEE, ITS LICENSEES
 * OR ANY OTHER THIRD PARTY, FOR ANY LOST PROFITS, LOST DATA, LOSS OF USE OR
 * COSTS OF PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES, OR FOR ANY INDIRECT,
 * SPECIAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THIS AGREEMENT, UNDER ANY
 * CAUSE OF ACTION OR THEORY OF LIABILITY, AND IRRESPECTIVE OF WHETHER INTEL
 * HAS ADVANCE NOTICE OF THE POSSIBILITY OF SUCH DAMAGES. THESE LIMITATIONS
 * SHALL APPLY NOTWITHSTANDING THE FAILURE OF THE ESSENTIAL PURPOSE OF ANY
 * LIMITED REMEDY.
 *
 * 4.3. Licensee shall not export, either directly or indirectly, any of this
 * software or system incorporating such software without first obtaining any
 * required license or other approval from the U. S. Department of Commerce or
 * any other agency or department of the United States Government. In the
 * event Licensee exports any such software from the United States or
 * re-exports any such software from a foreign destination, Licensee shall
 * ensure that the distribution and export/re-export of the software is in
 * compliance with all laws, regulations, orders, or other restrictions of the
 * U.S. Export Administration Regulations. Licensee agrees that neither it nor
 * any of its subsidiaries will export/re-export any technical data, process,
 * software, or service, directly or indirectly, to any country for which the
 * United States government or any agency thereof requires an export license,
 * other governmental approval, or letter of assurance, without first obtaining
 * such license, approval or letter.
 *
 *****************************************************************************
 *
 * Alternatively, you may choose to be licensed under the terms of the
 * following license:
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions, and the following disclaimer,
 *    without modification.
 * 2. Redistributions in binary form must reproduce at minimum a disclaimer
 *    substantially similar to the "NO WARRANTY" disclaimer below
 *    ("Disclaimer") and any redistribution must be conditioned upon
 *    including a substantially similar Disclaimer requirement for further
 *    binary redistribution.
 * 3. Neither the names of the above-listed copyright holders nor the names
 *    of any contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * Alternatively, you may choose to be licensed under the terms of the
 * GNU General Public License ("GPL") version 2 as published by the Free
 * Software Foundation.
 *
 *****************************************************************************/

#include <contrib/dev/acpica/include/acpi.h>
#include <contrib/dev/acpica/include/accommon.h>
#include <contrib/dev/acpica/include/acevents.h>

#define _COMPONENT          ACPI_HARDWARE
        ACPI_MODULE_NAME    ("hwregs")


#if (!ACPI_REDUCED_HARDWARE)

/* Local Prototypes */

static UINT8
AcpiHwGetAccessBitWidth (
    UINT64                  Address,
    ACPI_GENERIC_ADDRESS    *Reg,
    UINT8                   MaxBitWidth);

static ACPI_STATUS
AcpiHwReadMultiple (
    UINT32                  *Value,
    ACPI_GENERIC_ADDRESS    *RegisterA,
    ACPI_GENERIC_ADDRESS    *RegisterB);

static ACPI_STATUS
AcpiHwWriteMultiple (
    UINT32                  Value,
    ACPI_GENERIC_ADDRESS    *RegisterA,
    ACPI_GENERIC_ADDRESS    *RegisterB);

#endif /* !ACPI_REDUCED_HARDWARE */


/******************************************************************************
 *
 * FUNCTION:    AcpiHwGetAccessBitWidth
 *
 * PARAMETERS:  Address             - GAS register address
 *              Reg                 - GAS register structure
 *              MaxBitWidth         - Max BitWidth supported (32 or 64)
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Obtain optimal access bit width
 *
 ******************************************************************************/

static UINT8
AcpiHwGetAccessBitWidth (
    UINT64                  Address,
    ACPI_GENERIC_ADDRESS    *Reg,
    UINT8                   MaxBitWidth)
{
    UINT8                   AccessBitWidth;


    /*
     * GAS format "register", used by FADT:
     *  1. Detected if BitOffset is 0 and BitWidth is 8/16/32/64;
     *  2. AccessSize field is ignored and BitWidth field is used for
     *     determining the boundary of the IO accesses.
     * GAS format "region", used by APEI registers:
     *  1. Detected if BitOffset is not 0 or BitWidth is not 8/16/32/64;
     *  2. AccessSize field is used for determining the boundary of the
     *     IO accesses;
     *  3. BitOffset/BitWidth fields are used to describe the "region".
     *
     * Note: This algorithm assumes that the "Address" fields should always
     *       contain aligned values.
     */
    if (!Reg->BitOffset && Reg->BitWidth &&
        ACPI_IS_POWER_OF_TWO (Reg->BitWidth) &&
        ACPI_IS_ALIGNED (Reg->BitWidth, 8))
    {
        AccessBitWidth = Reg->BitWidth;
    }
    else if (Reg->AccessWidth)
    {
        AccessBitWidth = ACPI_ACCESS_BIT_WIDTH (Reg->AccessWidth);
    }
    else
    {
        AccessBitWidth = ACPI_ROUND_UP_POWER_OF_TWO_8 (
            Reg->BitOffset + Reg->BitWidth);
        if (AccessBitWidth <= 8)
        {
            AccessBitWidth = 8;
        }
        else
        {
            while (!ACPI_IS_ALIGNED (Address, AccessBitWidth >> 3))
            {
                AccessBitWidth >>= 1;
            }
        }
    }

    /* Maximum IO port access bit width is 32 */

    if (Reg->SpaceId == ACPI_ADR_SPACE_SYSTEM_IO)
    {
        MaxBitWidth = 32;
    }

    /*
     * Return access width according to the requested maximum access bit width,
     * as the caller should know the format of the register and may enforce
     * a 32-bit accesses.
     */
    if (AccessBitWidth < MaxBitWidth)
    {
        return (AccessBitWidth);
    }
    return (MaxBitWidth);
}


/******************************************************************************
 *
 * FUNCTION:    AcpiHwValidateRegister
 *
 * PARAMETERS:  Reg                 - GAS register structure
 *              MaxBitWidth         - Max BitWidth supported (32 or 64)
 *              Address             - Pointer to where the gas->address
 *                                    is returned
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Validate the contents of a GAS register. Checks the GAS
 *              pointer, Address, SpaceId, BitWidth, and BitOffset.
 *
 ******************************************************************************/

ACPI_STATUS
AcpiHwValidateRegister (
    ACPI_GENERIC_ADDRESS    *Reg,
    UINT8                   MaxBitWidth,
    UINT64                  *Address)
{
    UINT8                   BitWidth;
    UINT8                   AccessWidth;


    /* Must have a valid pointer to a GAS structure */

    if (!Reg)
    {
        return (AE_BAD_PARAMETER);
    }

    /*
     * Copy the target address. This handles possible alignment issues.
     * Address must not be null. A null address also indicates an optional
     * ACPI register that is not supported, so no error message.
     */
    ACPI_MOVE_64_TO_64 (Address, &Reg->Address);
    if (!(*Address))
    {
        return (AE_BAD_ADDRESS);
    }

    /* Validate the SpaceID */

    if ((Reg->SpaceId != ACPI_ADR_SPACE_SYSTEM_MEMORY) &&
        (Reg->SpaceId != ACPI_ADR_SPACE_SYSTEM_IO))
    {
        ACPI_ERROR ((AE_INFO,
            "Unsupported address space: 0x%X", Reg->SpaceId));
        return (AE_SUPPORT);
    }

    /* Validate the AccessWidth */

    if (Reg->AccessWidth > 4)
    {
        ACPI_ERROR ((AE_INFO,
            "Unsupported register access width: 0x%X", Reg->AccessWidth));
        return (AE_SUPPORT);
    }

    /* Validate the BitWidth, convert AccessWidth into number of bits */

    AccessWidth = AcpiHwGetAccessBitWidth (*Address, Reg, MaxBitWidth);
    BitWidth = ACPI_ROUND_UP (Reg->BitOffset + Reg->BitWidth, AccessWidth);
    if (MaxBitWidth < BitWidth)
    {
        ACPI_WARNING ((AE_INFO,
            "Requested bit width 0x%X is smaller than register bit width 0x%X",
            MaxBitWidth, BitWidth));
        return (AE_SUPPORT);
    }

    return (AE_OK);
}


/******************************************************************************
 *
 * FUNCTION:    AcpiHwRead
 *
 * PARAMETERS:  Value               - Where the value is returned
 *              Reg                 - GAS register structure
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Read from either memory or IO space. This is a 64-bit max
 *              version of AcpiRead.
 *
 * LIMITATIONS: <These limitations also apply to AcpiHwWrite>
 *      SpaceID must be SystemMemory or SystemIO.
 *
 ******************************************************************************/

ACPI_STATUS
AcpiHwRead (
    UINT64                  *Value,
    ACPI_GENERIC_ADDRESS    *Reg)
{
    UINT64                  Address;
    UINT8                   AccessWidth;
    UINT32                  BitWidth;
    UINT8                   BitOffset;
    UINT64                  Value64;
    UINT32                  Value32;
    UINT8                   Index;
    ACPI_STATUS             Status;


    ACPI_FUNCTION_NAME (HwRead);


    /* Validate contents of the GAS register */

    Status = AcpiHwValidateRegister (Reg, 64, &Address);
    if (ACPI_FAILURE (Status))
    {
        return (Status);
    }

    /*
     * Initialize entire 64-bit return value to zero, convert AccessWidth
     * into number of bits based
     */
    *Value = 0;
    AccessWidth = AcpiHwGetAccessBitWidth (Address, Reg, 64);
    BitWidth = Reg->BitOffset + Reg->BitWidth;
    BitOffset = Reg->BitOffset;

    /*
     * Two address spaces supported: Memory or IO. PCI_Config is
     * not supported here because the GAS structure is insufficient
     */
    Index = 0;
    while (BitWidth)
    {
        if (BitOffset >= AccessWidth)
        {
            Value64 = 0;
            BitOffset -= AccessWidth;
        }
        else
        {
            if (Reg->SpaceId == ACPI_ADR_SPACE_SYSTEM_MEMORY)
            {
                Status = AcpiOsReadMemory ((ACPI_PHYSICAL_ADDRESS)
                    Address + Index * ACPI_DIV_8 (AccessWidth),
                    &Value64, AccessWidth);
            }
            else /* ACPI_ADR_SPACE_SYSTEM_IO, validated earlier */
            {
                Status = AcpiHwReadPort ((ACPI_IO_ADDRESS)
                    Address + Index * ACPI_DIV_8 (AccessWidth),
                    &Value32, AccessWidth);
                Value64 = (UINT64) Value32;
            }
        }

        /*
         * Use offset style bit writes because "Index * AccessWidth" is
         * ensured to be less than 64-bits by AcpiHwValidateRegister().
         */
        ACPI_SET_BITS (Value, Index * AccessWidth,
            ACPI_MASK_BITS_ABOVE_64 (AccessWidth), Value64);

        BitWidth -= BitWidth > AccessWidth ? AccessWidth : BitWidth;
        Index++;
    }

    ACPI_DEBUG_PRINT ((ACPI_DB_IO,
        "Read:  %8.8X%8.8X width %2d from %8.8X%8.8X (%s)\n",
        ACPI_FORMAT_UINT64 (*Value), AccessWidth,
        ACPI_FORMAT_UINT64 (Address), AcpiUtGetRegionName (Reg->SpaceId)));

    return (Status);
}


/******************************************************************************
 *
 * FUNCTION:    AcpiHwWrite
 *
 * PARAMETERS:  Value               - Value to be written
 *              Reg                 - GAS register structure
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Write to either memory or IO space. This is a 64-bit max
 *              version of AcpiWrite.
 *
 ******************************************************************************/

ACPI_STATUS
AcpiHwWrite (
    UINT64                  Value,
    ACPI_GENERIC_ADDRESS    *Reg)
{
    UINT64                  Address;
    UINT8                   AccessWidth;
    UINT32                  BitWidth;
    UINT8                   BitOffset;
    UINT64                  Value64;
    UINT8                   Index;
    ACPI_STATUS             Status;


    ACPI_FUNCTION_NAME (HwWrite);


    /* Validate contents of the GAS register */

    Status = AcpiHwValidateRegister (Reg, 64, &Address);
    if (ACPI_FAILURE (Status))
    {
        return (Status);
    }

    /* Convert AccessWidth into number of bits based */

    AccessWidth = AcpiHwGetAccessBitWidth (Address, Reg, 64);
    BitWidth = Reg->BitOffset + Reg->BitWidth;
    BitOffset = Reg->BitOffset;

    /*
     * Two address spaces supported: Memory or IO. PCI_Config is
     * not supported here because the GAS structure is insufficient
     */
    Index = 0;
    while (BitWidth)
    {
        /*
         * Use offset style bit reads because "Index * AccessWidth" is
         * ensured to be less than 64-bits by AcpiHwValidateRegister().
         */
        Value64 = ACPI_GET_BITS (&Value, Index * AccessWidth,
            ACPI_MASK_BITS_ABOVE_64 (AccessWidth));

        if (BitOffset >= AccessWidth)
        {
            BitOffset -= AccessWidth;
        }
        else
        {
            if (Reg->SpaceId == ACPI_ADR_SPACE_SYSTEM_MEMORY)
            {
                Status = AcpiOsWriteMemory ((ACPI_PHYSICAL_ADDRESS)
                    Address + Index * ACPI_DIV_8 (AccessWidth),
                    Value64, AccessWidth);
            }
            else /* ACPI_ADR_SPACE_SYSTEM_IO, validated earlier */
            {
                Status = AcpiHwWritePort ((ACPI_IO_ADDRESS)
                    Address + Index * ACPI_DIV_8 (AccessWidth),
                    (UINT32) Value64, AccessWidth);
            }
        }

        /*
         * Index * AccessWidth is ensured to be less than 32-bits by
         * AcpiHwValidateRegister().
         */
        BitWidth -= BitWidth > AccessWidth ? AccessWidth : BitWidth;
        Index++;
    }

    ACPI_DEBUG_PRINT ((ACPI_DB_IO,
        "Wrote: %8.8X%8.8X width %2d   to %8.8X%8.8X (%s)\n",
        ACPI_FORMAT_UINT64 (Value), AccessWidth,
        ACPI_FORMAT_UINT64 (Address), AcpiUtGetRegionName (Reg->SpaceId)));

    return (Status);
}


#if (!ACPI_REDUCED_HARDWARE)
/*******************************************************************************
 *
 * FUNCTION:    AcpiHwClearAcpiStatus
 *
 * PARAMETERS:  None
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Clears all fixed and general purpose status bits
 *
 ******************************************************************************/

ACPI_STATUS
AcpiHwClearAcpiStatus (
    void)
{
    ACPI_STATUS             Status;
    ACPI_CPU_FLAGS          LockFlags = 0;


    ACPI_FUNCTION_TRACE (HwClearAcpiStatus);


    ACPI_DEBUG_PRINT ((ACPI_DB_IO, "About to write %04X to %8.8X%8.8X\n",
        ACPI_BITMASK_ALL_FIXED_STATUS,
        ACPI_FORMAT_UINT64 (AcpiGbl_XPm1aStatus.Address)));

    LockFlags = AcpiOsAcquireLock (AcpiGbl_HardwareLock);

    /* Clear the fixed events in PM1 A/B */

    Status = AcpiHwRegisterWrite (ACPI_REGISTER_PM1_STATUS,
        ACPI_BITMASK_ALL_FIXED_STATUS);

    AcpiOsReleaseLock (AcpiGbl_HardwareLock, LockFlags);

    if (ACPI_FAILURE (Status))
    {
        goto Exit;
    }

    /* Clear the GPE Bits in all GPE registers in all GPE blocks */

    Status = AcpiEvWalkGpeList (AcpiHwClearGpeBlock, NULL);

Exit:
    return_ACPI_STATUS (Status);
}


/*******************************************************************************
 *
 * FUNCTION:    AcpiHwGetBitRegisterInfo
 *
 * PARAMETERS:  RegisterId          - Index of ACPI Register to access
 *
 * RETURN:      The bitmask to be used when accessing the register
 *
 * DESCRIPTION: Map RegisterId into a register bitmask.
 *
 ******************************************************************************/

ACPI_BIT_REGISTER_INFO *
AcpiHwGetBitRegisterInfo (
    UINT32                  RegisterId)
{
    ACPI_FUNCTION_ENTRY ();


    if (RegisterId > ACPI_BITREG_MAX)
    {
        ACPI_ERROR ((AE_INFO, "Invalid BitRegister ID: 0x%X", RegisterId));
        return (NULL);
    }

    return (&AcpiGbl_BitRegisterInfo[RegisterId]);
}


/******************************************************************************
 *
 * FUNCTION:    AcpiHwWritePm1Control
 *
 * PARAMETERS:  Pm1aControl         - Value to be written to PM1A control
 *              Pm1bControl         - Value to be written to PM1B control
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Write the PM1 A/B control registers. These registers are
 *              different than than the PM1 A/B status and enable registers
 *              in that different values can be written to the A/B registers.
 *              Most notably, the SLP_TYP bits can be different, as per the
 *              values returned from the _Sx predefined methods.
 *
 ******************************************************************************/

ACPI_STATUS
AcpiHwWritePm1Control (
    UINT32                  Pm1aControl,
    UINT32                  Pm1bControl)
{
    ACPI_STATUS             Status;


    ACPI_FUNCTION_TRACE (HwWritePm1Control);


    Status = AcpiHwWrite (Pm1aControl, &AcpiGbl_FADT.XPm1aControlBlock);
    if (ACPI_FAILURE (Status))
    {
        return_ACPI_STATUS (Status);
    }

    if (AcpiGbl_FADT.XPm1bControlBlock.Address)
    {
        Status = AcpiHwWrite (Pm1bControl, &AcpiGbl_FADT.XPm1bControlBlock);
    }
    return_ACPI_STATUS (Status);
}


/******************************************************************************
 *
 * FUNCTION:    AcpiHwRegisterRead
 *
 * PARAMETERS:  RegisterId          - ACPI Register ID
 *              ReturnValue         - Where the register value is returned
 *
 * RETURN:      Status and the value read.
 *
 * DESCRIPTION: Read from the specified ACPI register
 *
 ******************************************************************************/

ACPI_STATUS
AcpiHwRegisterRead (
    UINT32                  RegisterId,
    UINT32                  *ReturnValue)
{
    UINT32                  Value = 0;
    UINT64                  Value64;
    ACPI_STATUS             Status;


    ACPI_FUNCTION_TRACE (HwRegisterRead);


    switch (RegisterId)
    {
    case ACPI_REGISTER_PM1_STATUS:           /* PM1 A/B: 16-bit access each */

        Status = AcpiHwReadMultiple (&Value,
            &AcpiGbl_XPm1aStatus,
            &AcpiGbl_XPm1bStatus);
        break;

    case ACPI_REGISTER_PM1_ENABLE:           /* PM1 A/B: 16-bit access each */

        Status = AcpiHwReadMultiple (&Value,
            &AcpiGbl_XPm1aEnable,
            &AcpiGbl_XPm1bEnable);
        break;

    case ACPI_REGISTER_PM1_CONTROL:          /* PM1 A/B: 16-bit access each */

        Status = AcpiHwReadMultiple (&Value,
            &AcpiGbl_FADT.XPm1aControlBlock,
            &AcpiGbl_FADT.XPm1bControlBlock);

        /*
         * Zero the write-only bits. From the ACPI specification, "Hardware
         * Write-Only Bits": "Upon reads to registers with write-only bits,
         * software masks out all write-only bits."
         */
        Value &= ~ACPI_PM1_CONTROL_WRITEONLY_BITS;
        break;

    case ACPI_REGISTER_PM2_CONTROL:          /* 8-bit access */

        Status = AcpiHwRead (&Value64, &AcpiGbl_FADT.XPm2ControlBlock);
        if (ACPI_SUCCESS (Status))
        {
            Value = (UINT32) Value64;
        }
        break;

    case ACPI_REGISTER_PM_TIMER:             /* 32-bit access */

        Status = AcpiHwRead (&Value64, &AcpiGbl_FADT.XPmTimerBlock);
        if (ACPI_SUCCESS (Status))
        {
            Value = (UINT32) Value64;
        }

        break;

    case ACPI_REGISTER_SMI_COMMAND_BLOCK:    /* 8-bit access */

        Status = AcpiHwReadPort (AcpiGbl_FADT.SmiCommand, &Value, 8);
        break;

    default:

        ACPI_ERROR ((AE_INFO, "Unknown Register ID: 0x%X",
            RegisterId));
        Status = AE_BAD_PARAMETER;
        break;
    }

    if (ACPI_SUCCESS (Status))
    {
        *ReturnValue = (UINT32) Value;
    }

    return_ACPI_STATUS (Status);
}


/******************************************************************************
 *
 * FUNCTION:    AcpiHwRegisterWrite
 *
 * PARAMETERS:  RegisterId          - ACPI Register ID
 *              Value               - The value to write
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Write to the specified ACPI register
 *
 * NOTE: In accordance with the ACPI specification, this function automatically
 * preserves the value of the following bits, meaning that these bits cannot be
 * changed via this interface:
 *
 * PM1_CONTROL[0] = SCI_EN
 * PM1_CONTROL[9]
 * PM1_STATUS[11]
 *
 * ACPI References:
 * 1) Hardware Ignored Bits: When software writes to a register with ignored
 *      bit fields, it preserves the ignored bit fields
 * 2) SCI_EN: OSPM always preserves this bit position
 *
 ******************************************************************************/

ACPI_STATUS
AcpiHwRegisterWrite (
    UINT32                  RegisterId,
    UINT32                  Value)
{
    ACPI_STATUS             Status;
    UINT32                  ReadValue;
    UINT64                  ReadValue64;


    ACPI_FUNCTION_TRACE (HwRegisterWrite);


    switch (RegisterId)
    {
    case ACPI_REGISTER_PM1_STATUS:           /* PM1 A/B: 16-bit access each */
        /*
         * Handle the "ignored" bit in PM1 Status. According to the ACPI
         * specification, ignored bits are to be preserved when writing.
         * Normally, this would mean a read/modify/write sequence. However,
         * preserving a bit in the status register is different. Writing a
         * one clears the status, and writing a zero preserves the status.
         * Therefore, we must always write zero to the ignored bit.
         *
         * This behavior is clarified in the ACPI 4.0 specification.
         */
        Value &= ~ACPI_PM1_STATUS_PRESERVED_BITS;

        Status = AcpiHwWriteMultiple (Value,
            &AcpiGbl_XPm1aStatus,
            &AcpiGbl_XPm1bStatus);
        break;

    case ACPI_REGISTER_PM1_ENABLE:           /* PM1 A/B: 16-bit access each */

        Status = AcpiHwWriteMultiple (Value,
            &AcpiGbl_XPm1aEnable,
            &AcpiGbl_XPm1bEnable);
        break;

    case ACPI_REGISTER_PM1_CONTROL:          /* PM1 A/B: 16-bit access each */
        /*
         * Perform a read first to preserve certain bits (per ACPI spec)
         * Note: This includes SCI_EN, we never want to change this bit
         */
        Status = AcpiHwReadMultiple (&ReadValue,
            &AcpiGbl_FADT.XPm1aControlBlock,
            &AcpiGbl_FADT.XPm1bControlBlock);
        if (ACPI_FAILURE (Status))
        {
            goto Exit;
        }

        /* Insert the bits to be preserved */

        ACPI_INSERT_BITS (Value, ACPI_PM1_CONTROL_PRESERVED_BITS, ReadValue);

        /* Now we can write the data */

        Status = AcpiHwWriteMultiple (Value,
            &AcpiGbl_FADT.XPm1aControlBlock,
            &AcpiGbl_FADT.XPm1bControlBlock);
        break;

    case ACPI_REGISTER_PM2_CONTROL:          /* 8-bit access */
        /*
         * For control registers, all reserved bits must be preserved,
         * as per the ACPI spec.
         */
        Status = AcpiHwRead (&ReadValue64, &AcpiGbl_FADT.XPm2ControlBlock);
        if (ACPI_FAILURE (Status))
        {
            goto Exit;
        }
        ReadValue = (UINT32) ReadValue64;

        /* Insert the bits to be preserved */

        ACPI_INSERT_BITS (Value, ACPI_PM2_CONTROL_PRESERVED_BITS, ReadValue);

        Status = AcpiHwWrite (Value, &AcpiGbl_FADT.XPm2ControlBlock);
        break;

    case ACPI_REGISTER_PM_TIMER:             /* 32-bit access */

        Status = AcpiHwWrite (Value, &AcpiGbl_FADT.XPmTimerBlock);
        break;

    case ACPI_REGISTER_SMI_COMMAND_BLOCK:    /* 8-bit access */

        /* SMI_CMD is currently always in IO space */

        Status = AcpiHwWritePort (AcpiGbl_FADT.SmiCommand, Value, 8);
        break;

    default:

        ACPI_ERROR ((AE_INFO, "Unknown Register ID: 0x%X",
            RegisterId));
        Status = AE_BAD_PARAMETER;
        break;
    }

Exit:
    return_ACPI_STATUS (Status);
}


/******************************************************************************
 *
 * FUNCTION:    AcpiHwReadMultiple
 *
 * PARAMETERS:  Value               - Where the register value is returned
 *              RegisterA           - First ACPI register (required)
 *              RegisterB           - Second ACPI register (optional)
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Read from the specified two-part ACPI register (such as PM1 A/B)
 *
 ******************************************************************************/

static ACPI_STATUS
AcpiHwReadMultiple (
    UINT32                  *Value,
    ACPI_GENERIC_ADDRESS    *RegisterA,
    ACPI_GENERIC_ADDRESS    *RegisterB)
{
    UINT32                  ValueA = 0;
    UINT32                  ValueB = 0;
    UINT64                  Value64;
    ACPI_STATUS             Status;


    /* The first register is always required */

    Status = AcpiHwRead (&Value64, RegisterA);
    if (ACPI_FAILURE (Status))
    {
        return (Status);
    }
    ValueA = (UINT32) Value64;

    /* Second register is optional */

    if (RegisterB->Address)
    {
        Status = AcpiHwRead (&Value64, RegisterB);
        if (ACPI_FAILURE (Status))
        {
            return (Status);
        }
        ValueB = (UINT32) Value64;
    }

    /*
     * OR the two return values together. No shifting or masking is necessary,
     * because of how the PM1 registers are defined in the ACPI specification:
     *
     * "Although the bits can be split between the two register blocks (each
     * register block has a unique pointer within the FADT), the bit positions
     * are maintained. The register block with unimplemented bits (that is,
     * those implemented in the other register block) always returns zeros,
     * and writes have no side effects"
     */
    *Value = (ValueA | ValueB);
    return (AE_OK);
}


/******************************************************************************
 *
 * FUNCTION:    AcpiHwWriteMultiple
 *
 * PARAMETERS:  Value               - The value to write
 *              RegisterA           - First ACPI register (required)
 *              RegisterB           - Second ACPI register (optional)
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Write to the specified two-part ACPI register (such as PM1 A/B)
 *
 ******************************************************************************/

static ACPI_STATUS
AcpiHwWriteMultiple (
    UINT32                  Value,
    ACPI_GENERIC_ADDRESS    *RegisterA,
    ACPI_GENERIC_ADDRESS    *RegisterB)
{
    ACPI_STATUS             Status;


    /* The first register is always required */

    Status = AcpiHwWrite (Value, RegisterA);
    if (ACPI_FAILURE (Status))
    {
        return (Status);
    }

    /*
     * Second register is optional
     *
     * No bit shifting or clearing is necessary, because of how the PM1
     * registers are defined in the ACPI specification:
     *
     * "Although the bits can be split between the two register blocks (each
     * register block has a unique pointer within the FADT), the bit positions
     * are maintained. The register block with unimplemented bits (that is,
     * those implemented in the other register block) always returns zeros,
     * and writes have no side effects"
     */
    if (RegisterB->Address)
    {
        Status = AcpiHwWrite (Value, RegisterB);
    }

    return (Status);
}

#endif /* !ACPI_REDUCED_HARDWARE */