
/******************************************************************************
 *
 * Module Name: exprep - ACPI AML (p-code) execution - field prep utilities
 *
 *****************************************************************************/

/******************************************************************************
 *
 * 1. Copyright Notice
 *
 * Some or all of this work - Copyright (c) 1999 - 2012, 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.
 *
 *****************************************************************************/

#define __EXPREP_C__

#include "acpi.h"
#include "accommon.h"
#include "acinterp.h"
#include "amlcode.h"
#include "acnamesp.h"
#include "acdispat.h"


#define _COMPONENT          ACPI_EXECUTER
        ACPI_MODULE_NAME    ("exprep")

/* Local prototypes */

static UINT32
AcpiExDecodeFieldAccess (
    ACPI_OPERAND_OBJECT     *ObjDesc,
    UINT8                   FieldFlags,
    UINT32                  *ReturnByteAlignment);


#ifdef ACPI_UNDER_DEVELOPMENT

static UINT32
AcpiExGenerateAccess (
    UINT32                  FieldBitOffset,
    UINT32                  FieldBitLength,
    UINT32                  RegionLength);

/*******************************************************************************
 *
 * FUNCTION:    AcpiExGenerateAccess
 *
 * PARAMETERS:  FieldBitOffset      - Start of field within parent region/buffer
 *              FieldBitLength      - Length of field in bits
 *              RegionLength        - Length of parent in bytes
 *
 * RETURN:      Field granularity (8, 16, 32 or 64) and
 *              ByteAlignment (1, 2, 3, or 4)
 *
 * DESCRIPTION: Generate an optimal access width for fields defined with the
 *              AnyAcc keyword.
 *
 * NOTE: Need to have the RegionLength in order to check for boundary
 *       conditions (end-of-region).  However, the RegionLength is a deferred
 *       operation.  Therefore, to complete this implementation, the generation
 *       of this access width must be deferred until the region length has
 *       been evaluated.
 *
 ******************************************************************************/

static UINT32
AcpiExGenerateAccess (
    UINT32                  FieldBitOffset,
    UINT32                  FieldBitLength,
    UINT32                  RegionLength)
{
    UINT32                  FieldByteLength;
    UINT32                  FieldByteOffset;
    UINT32                  FieldByteEndOffset;
    UINT32                  AccessByteWidth;
    UINT32                  FieldStartOffset;
    UINT32                  FieldEndOffset;
    UINT32                  MinimumAccessWidth = 0xFFFFFFFF;
    UINT32                  MinimumAccesses = 0xFFFFFFFF;
    UINT32                  Accesses;


    ACPI_FUNCTION_TRACE (ExGenerateAccess);


    /* Round Field start offset and length to "minimal" byte boundaries */

    FieldByteOffset    = ACPI_DIV_8 (ACPI_ROUND_DOWN (FieldBitOffset, 8));
    FieldByteEndOffset = ACPI_DIV_8 (ACPI_ROUND_UP   (FieldBitLength +
                                                      FieldBitOffset, 8));
    FieldByteLength    = FieldByteEndOffset - FieldByteOffset;

    ACPI_DEBUG_PRINT ((ACPI_DB_BFIELD,
        "Bit length %u, Bit offset %u\n",
        FieldBitLength, FieldBitOffset));

    ACPI_DEBUG_PRINT ((ACPI_DB_BFIELD,
        "Byte Length %u, Byte Offset %u, End Offset %u\n",
        FieldByteLength, FieldByteOffset, FieldByteEndOffset));

    /*
     * Iterative search for the maximum access width that is both aligned
     * and does not go beyond the end of the region
     *
     * Start at ByteAcc and work upwards to QwordAcc max. (1,2,4,8 bytes)
     */
    for (AccessByteWidth = 1; AccessByteWidth <= 8; AccessByteWidth <<= 1)
    {
        /*
         * 1) Round end offset up to next access boundary and make sure that
         *    this does not go beyond the end of the parent region.
         * 2) When the Access width is greater than the FieldByteLength, we
         *    are done. (This does not optimize for the perfectly aligned
         *    case yet).
         */
        if (ACPI_ROUND_UP (FieldByteEndOffset, AccessByteWidth) <= RegionLength)
        {
            FieldStartOffset =
                ACPI_ROUND_DOWN (FieldByteOffset, AccessByteWidth) /
                AccessByteWidth;

            FieldEndOffset =
                ACPI_ROUND_UP ((FieldByteLength + FieldByteOffset),
                    AccessByteWidth) / AccessByteWidth;

            Accesses = FieldEndOffset - FieldStartOffset;

            ACPI_DEBUG_PRINT ((ACPI_DB_BFIELD,
                "AccessWidth %u end is within region\n", AccessByteWidth));

            ACPI_DEBUG_PRINT ((ACPI_DB_BFIELD,
                "Field Start %u, Field End %u -- requires %u accesses\n",
                FieldStartOffset, FieldEndOffset, Accesses));

            /* Single access is optimal */

            if (Accesses <= 1)
            {
                ACPI_DEBUG_PRINT ((ACPI_DB_BFIELD,
                    "Entire field can be accessed with one operation of size %u\n",
                    AccessByteWidth));
                return_VALUE (AccessByteWidth);
            }

            /*
             * Fits in the region, but requires more than one read/write.
             * try the next wider access on next iteration
             */
            if (Accesses < MinimumAccesses)
            {
                MinimumAccesses    = Accesses;
                MinimumAccessWidth = AccessByteWidth;
            }
        }
        else
        {
            ACPI_DEBUG_PRINT ((ACPI_DB_BFIELD,
                "AccessWidth %u end is NOT within region\n", AccessByteWidth));
            if (AccessByteWidth == 1)
            {
                ACPI_DEBUG_PRINT ((ACPI_DB_BFIELD,
                    "Field goes beyond end-of-region!\n"));

                /* Field does not fit in the region at all */

                return_VALUE (0);
            }

            /*
             * This width goes beyond the end-of-region, back off to
             * previous access
             */
            ACPI_DEBUG_PRINT ((ACPI_DB_BFIELD,
                "Backing off to previous optimal access width of %u\n",
                MinimumAccessWidth));
            return_VALUE (MinimumAccessWidth);
        }
    }

    /*
     * Could not read/write field with one operation,
     * just use max access width
     */
    ACPI_DEBUG_PRINT ((ACPI_DB_BFIELD,
        "Cannot access field in one operation, using width 8\n"));
    return_VALUE (8);
}
#endif /* ACPI_UNDER_DEVELOPMENT */


/*******************************************************************************
 *
 * FUNCTION:    AcpiExDecodeFieldAccess
 *
 * PARAMETERS:  ObjDesc             - Field object
 *              FieldFlags          - Encoded fieldflags (contains access bits)
 *              ReturnByteAlignment - Where the byte alignment is returned
 *
 * RETURN:      Field granularity (8, 16, 32 or 64) and
 *              ByteAlignment (1, 2, 3, or 4)
 *
 * DESCRIPTION: Decode the AccessType bits of a field definition.
 *
 ******************************************************************************/

static UINT32
AcpiExDecodeFieldAccess (
    ACPI_OPERAND_OBJECT     *ObjDesc,
    UINT8                   FieldFlags,
    UINT32                  *ReturnByteAlignment)
{
    UINT32                  Access;
    UINT32                  ByteAlignment;
    UINT32                  BitLength;


    ACPI_FUNCTION_TRACE (ExDecodeFieldAccess);


    Access = (FieldFlags & AML_FIELD_ACCESS_TYPE_MASK);

    switch (Access)
    {
    case AML_FIELD_ACCESS_ANY:

#ifdef ACPI_UNDER_DEVELOPMENT
        ByteAlignment =
            AcpiExGenerateAccess (ObjDesc->CommonField.StartFieldBitOffset,
                ObjDesc->CommonField.BitLength,
                0xFFFFFFFF /* Temp until we pass RegionLength as parameter */);
        BitLength = ByteAlignment * 8;
#endif

        ByteAlignment = 1;
        BitLength = 8;
        break;

    case AML_FIELD_ACCESS_BYTE:
    case AML_FIELD_ACCESS_BUFFER:   /* ACPI 2.0 (SMBus Buffer) */
        ByteAlignment = 1;
        BitLength     = 8;
        break;

    case AML_FIELD_ACCESS_WORD:
        ByteAlignment = 2;
        BitLength     = 16;
        break;

    case AML_FIELD_ACCESS_DWORD:
        ByteAlignment = 4;
        BitLength     = 32;
        break;

    case AML_FIELD_ACCESS_QWORD:    /* ACPI 2.0 */
        ByteAlignment = 8;
        BitLength     = 64;
        break;

    default:
        /* Invalid field access type */

        ACPI_ERROR ((AE_INFO,
            "Unknown field access type 0x%X",
            Access));
        return_UINT32 (0);
    }

    if (ObjDesc->Common.Type == ACPI_TYPE_BUFFER_FIELD)
    {
        /*
         * BufferField access can be on any byte boundary, so the
         * ByteAlignment is always 1 byte -- regardless of any ByteAlignment
         * implied by the field access type.
         */
        ByteAlignment = 1;
    }

    *ReturnByteAlignment = ByteAlignment;
    return_UINT32 (BitLength);
}


/*******************************************************************************
 *
 * FUNCTION:    AcpiExPrepCommonFieldObject
 *
 * PARAMETERS:  ObjDesc             - The field object
 *              FieldFlags          - Access, LockRule, and UpdateRule.
 *                                    The format of a FieldFlag is described
 *                                    in the ACPI specification
 *              FieldAttribute      - Special attributes (not used)
 *              FieldBitPosition    - Field start position
 *              FieldBitLength      - Field length in number of bits
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Initialize the areas of the field object that are common
 *              to the various types of fields.  Note: This is very "sensitive"
 *              code because we are solving the general case for field
 *              alignment.
 *
 ******************************************************************************/

ACPI_STATUS
AcpiExPrepCommonFieldObject (
    ACPI_OPERAND_OBJECT     *ObjDesc,
    UINT8                   FieldFlags,
    UINT8                   FieldAttribute,
    UINT32                  FieldBitPosition,
    UINT32                  FieldBitLength)
{
    UINT32                  AccessBitWidth;
    UINT32                  ByteAlignment;
    UINT32                  NearestByteAddress;


    ACPI_FUNCTION_TRACE (ExPrepCommonFieldObject);


    /*
     * Note: the structure being initialized is the
     * ACPI_COMMON_FIELD_INFO;  No structure fields outside of the common
     * area are initialized by this procedure.
     */
    ObjDesc->CommonField.FieldFlags = FieldFlags;
    ObjDesc->CommonField.Attribute  = FieldAttribute;
    ObjDesc->CommonField.BitLength  = FieldBitLength;

    /*
     * Decode the access type so we can compute offsets.  The access type gives
     * two pieces of information - the width of each field access and the
     * necessary ByteAlignment (address granularity) of the access.
     *
     * For AnyAcc, the AccessBitWidth is the largest width that is both
     * necessary and possible in an attempt to access the whole field in one
     * I/O operation.  However, for AnyAcc, the ByteAlignment is always one
     * byte.
     *
     * For all Buffer Fields, the ByteAlignment is always one byte.
     *
     * For all other access types (Byte, Word, Dword, Qword), the Bitwidth is
     * the same (equivalent) as the ByteAlignment.
     */
    AccessBitWidth = AcpiExDecodeFieldAccess (ObjDesc, FieldFlags,
                        &ByteAlignment);
    if (!AccessBitWidth)
    {
        return_ACPI_STATUS (AE_AML_OPERAND_VALUE);
    }

    /* Setup width (access granularity) fields (values are: 1, 2, 4, 8) */

    ObjDesc->CommonField.AccessByteWidth = (UINT8)
        ACPI_DIV_8 (AccessBitWidth);

    /*
     * BaseByteOffset is the address of the start of the field within the
     * region.  It is the byte address of the first *datum* (field-width data
     * unit) of the field. (i.e., the first datum that contains at least the
     * first *bit* of the field.)
     *
     * Note: ByteAlignment is always either equal to the AccessBitWidth or 8
     * (Byte access), and it defines the addressing granularity of the parent
     * region or buffer.
     */
    NearestByteAddress =
        ACPI_ROUND_BITS_DOWN_TO_BYTES (FieldBitPosition);
    ObjDesc->CommonField.BaseByteOffset = (UINT32)
        ACPI_ROUND_DOWN (NearestByteAddress, ByteAlignment);

    /*
     * StartFieldBitOffset is the offset of the first bit of the field within
     * a field datum.
     */
    ObjDesc->CommonField.StartFieldBitOffset = (UINT8)
        (FieldBitPosition - ACPI_MUL_8 (ObjDesc->CommonField.BaseByteOffset));

    return_ACPI_STATUS (AE_OK);
}


/*******************************************************************************
 *
 * FUNCTION:    AcpiExPrepFieldValue
 *
 * PARAMETERS:  Info    - Contains all field creation info
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Construct an ACPI_OPERAND_OBJECT of type DefField and
 *              connect it to the parent Node.
 *
 ******************************************************************************/

ACPI_STATUS
AcpiExPrepFieldValue (
    ACPI_CREATE_FIELD_INFO  *Info)
{
    ACPI_OPERAND_OBJECT     *ObjDesc;
    ACPI_OPERAND_OBJECT     *SecondDesc = NULL;
    ACPI_STATUS             Status;
    UINT32                  AccessByteWidth;
    UINT32                  Type;


    ACPI_FUNCTION_TRACE (ExPrepFieldValue);


    /* Parameter validation */

    if (Info->FieldType != ACPI_TYPE_LOCAL_INDEX_FIELD)
    {
        if (!Info->RegionNode)
        {
            ACPI_ERROR ((AE_INFO, "Null RegionNode"));
            return_ACPI_STATUS (AE_AML_NO_OPERAND);
        }

        Type = AcpiNsGetType (Info->RegionNode);
        if (Type != ACPI_TYPE_REGION)
        {
            ACPI_ERROR ((AE_INFO, "Needed Region, found type 0x%X (%s)",
                Type, AcpiUtGetTypeName (Type)));

            return_ACPI_STATUS (AE_AML_OPERAND_TYPE);
        }
    }

    /* Allocate a new field object */

    ObjDesc = AcpiUtCreateInternalObject (Info->FieldType);
    if (!ObjDesc)
    {
        return_ACPI_STATUS (AE_NO_MEMORY);
    }

    /* Initialize areas of the object that are common to all fields */

    ObjDesc->CommonField.Node = Info->FieldNode;
    Status = AcpiExPrepCommonFieldObject (ObjDesc,
                Info->FieldFlags, Info->Attribute,
                Info->FieldBitPosition, Info->FieldBitLength);
    if (ACPI_FAILURE (Status))
    {
        AcpiUtDeleteObjectDesc (ObjDesc);
        return_ACPI_STATUS (Status);
    }

    /* Initialize areas of the object that are specific to the field type */

    switch (Info->FieldType)
    {
    case ACPI_TYPE_LOCAL_REGION_FIELD:

        ObjDesc->Field.RegionObj = AcpiNsGetAttachedObject (Info->RegionNode);

        /* Fields specific to GenericSerialBus fields */

        ObjDesc->Field.AccessLength = Info->AccessLength;

        if (Info->ConnectionNode)
        {
            SecondDesc = Info->ConnectionNode->Object;
            if (!(SecondDesc->Common.Flags & AOPOBJ_DATA_VALID))
            {
                Status = AcpiDsGetBufferArguments (SecondDesc);
                if (ACPI_FAILURE (Status))
                {
                    AcpiUtDeleteObjectDesc (ObjDesc);
                    return_ACPI_STATUS (Status);
                }
            }

            ObjDesc->Field.ResourceBuffer = SecondDesc->Buffer.Pointer;
            ObjDesc->Field.ResourceLength = (UINT16) SecondDesc->Buffer.Length;
        }
        else if (Info->ResourceBuffer)
        {
            ObjDesc->Field.ResourceBuffer = Info->ResourceBuffer;
            ObjDesc->Field.ResourceLength = Info->ResourceLength;
        }

        /* Allow full data read from EC address space */

        if ((ObjDesc->Field.RegionObj->Region.SpaceId == ACPI_ADR_SPACE_EC) &&
            (ObjDesc->CommonField.BitLength > 8))
        {
            AccessByteWidth = ACPI_ROUND_BITS_UP_TO_BYTES (
                ObjDesc->CommonField.BitLength);

            /* Maximum byte width supported is 255 */

            if (AccessByteWidth < 256)
            {
                ObjDesc->CommonField.AccessByteWidth = (UINT8) AccessByteWidth;
            }
        }

        /* An additional reference for the container */

        AcpiUtAddReference (ObjDesc->Field.RegionObj);

        ACPI_DEBUG_PRINT ((ACPI_DB_BFIELD,
            "RegionField: BitOff %X, Off %X, Gran %X, Region %p\n",
            ObjDesc->Field.StartFieldBitOffset, ObjDesc->Field.BaseByteOffset,
            ObjDesc->Field.AccessByteWidth, ObjDesc->Field.RegionObj));
        break;


    case ACPI_TYPE_LOCAL_BANK_FIELD:

        ObjDesc->BankField.Value = Info->BankValue;
        ObjDesc->BankField.RegionObj =
            AcpiNsGetAttachedObject (Info->RegionNode);
        ObjDesc->BankField.BankObj =
            AcpiNsGetAttachedObject (Info->RegisterNode);

        /* An additional reference for the attached objects */

        AcpiUtAddReference (ObjDesc->BankField.RegionObj);
        AcpiUtAddReference (ObjDesc->BankField.BankObj);

        ACPI_DEBUG_PRINT ((ACPI_DB_BFIELD,
            "Bank Field: BitOff %X, Off %X, Gran %X, Region %p, BankReg %p\n",
            ObjDesc->BankField.StartFieldBitOffset,
            ObjDesc->BankField.BaseByteOffset,
            ObjDesc->Field.AccessByteWidth,
            ObjDesc->BankField.RegionObj,
            ObjDesc->BankField.BankObj));

        /*
         * Remember location in AML stream of the field unit
         * opcode and operands -- since the BankValue
         * operands must be evaluated.
         */
        SecondDesc = ObjDesc->Common.NextObject;
        SecondDesc->Extra.AmlStart = ACPI_CAST_PTR (ACPI_PARSE_OBJECT,
            Info->DataRegisterNode)->Named.Data;
        SecondDesc->Extra.AmlLength = ACPI_CAST_PTR (ACPI_PARSE_OBJECT,
            Info->DataRegisterNode)->Named.Length;

        break;


    case ACPI_TYPE_LOCAL_INDEX_FIELD:

        /* Get the Index and Data registers */

        ObjDesc->IndexField.IndexObj =
            AcpiNsGetAttachedObject (Info->RegisterNode);
        ObjDesc->IndexField.DataObj =
            AcpiNsGetAttachedObject (Info->DataRegisterNode);

        if (!ObjDesc->IndexField.DataObj || !ObjDesc->IndexField.IndexObj)
        {
            ACPI_ERROR ((AE_INFO, "Null Index Object during field prep"));
            AcpiUtDeleteObjectDesc (ObjDesc);
            return_ACPI_STATUS (AE_AML_INTERNAL);
        }

        /* An additional reference for the attached objects */

        AcpiUtAddReference (ObjDesc->IndexField.DataObj);
        AcpiUtAddReference (ObjDesc->IndexField.IndexObj);

        /*
         * April 2006: Changed to match MS behavior
         *
         * The value written to the Index register is the byte offset of the
         * target field in units of the granularity of the IndexField
         *
         * Previously, the value was calculated as an index in terms of the
         * width of the Data register, as below:
         *
         *      ObjDesc->IndexField.Value = (UINT32)
         *          (Info->FieldBitPosition / ACPI_MUL_8 (
         *              ObjDesc->Field.AccessByteWidth));
         *
         * February 2006: Tried value as a byte offset:
         *      ObjDesc->IndexField.Value = (UINT32)
         *          ACPI_DIV_8 (Info->FieldBitPosition);
         */
        ObjDesc->IndexField.Value = (UINT32) ACPI_ROUND_DOWN (
            ACPI_DIV_8 (Info->FieldBitPosition),
            ObjDesc->IndexField.AccessByteWidth);

        ACPI_DEBUG_PRINT ((ACPI_DB_BFIELD,
            "IndexField: BitOff %X, Off %X, Value %X, Gran %X, Index %p, Data %p\n",
            ObjDesc->IndexField.StartFieldBitOffset,
            ObjDesc->IndexField.BaseByteOffset,
            ObjDesc->IndexField.Value,
            ObjDesc->Field.AccessByteWidth,
            ObjDesc->IndexField.IndexObj,
            ObjDesc->IndexField.DataObj));
        break;

    default:
        /* No other types should get here */
        break;
    }

    /*
     * Store the constructed descriptor (ObjDesc) into the parent Node,
     * preserving the current type of that NamedObj.
     */
    Status = AcpiNsAttachObject (Info->FieldNode, ObjDesc,
                AcpiNsGetType (Info->FieldNode));

    ACPI_DEBUG_PRINT ((ACPI_DB_BFIELD, "Set NamedObj %p [%4.4s], ObjDesc %p\n",
        Info->FieldNode, AcpiUtGetNodeName (Info->FieldNode), ObjDesc));

    /* Remove local reference to the object */

    AcpiUtRemoveReference (ObjDesc);
    return_ACPI_STATUS (Status);
}

