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/******************************************************************************

 *

 * Module Name: exfldio - Aml Field I/O

 *

 *****************************************************************************/

/*

 * Copyright (C) 2000 - 2004, R. Byron Moore

 * All rights reserved.

 *

 * 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.

 *

 * Alternatively, this software may be distributed under the terms of the

 * GNU General Public License ("GPL") version 2 as published by the Free

 * Software Foundation.

 *

 * NO WARRANTY

 * 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 MERCHANTIBILITY AND FITNESS FOR

 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT

 * HOLDERS OR CONTRIBUTORS BE LIABLE FOR 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 DAMAGES.

 */

#include <acpi/acpi.h>

#include <acpi/acinterp.h>

#include <acpi/amlcode.h>

#include <acpi/acevents.h>

#include <acpi/acdispat.h>

#define _COMPONENT          ACPI_EXECUTER

         ACPI_MODULE_NAME    ("exfldio")

/*******************************************************************************

 *

 * FUNCTION:    acpi_ex_setup_region

 *

 * PARAMETERS:  *obj_desc               - Field to be read or written

 *              field_datum_byte_offset - Byte offset of this datum within the

 *                                        parent field

 *

 * RETURN:      Status

 *

 * DESCRIPTION: Common processing for acpi_ex_extract_from_field and

 *              acpi_ex_insert_into_field. Initialize the Region if necessary and

 *              validate the request.

 *

 ******************************************************************************/

acpi_status

acpi_ex_setup_region (

        union acpi_operand_object       *obj_desc,

        u32                             field_datum_byte_offset)

{

        acpi_status                     status = AE_OK;

        union acpi_operand_object       *rgn_desc;

        ACPI_FUNCTION_TRACE_U32 ("ex_setup_region", field_datum_byte_offset);

        rgn_desc = obj_desc->common_field.region_obj;

        /* We must have a valid region */

        if (ACPI_GET_OBJECT_TYPE (rgn_desc) != ACPI_TYPE_REGION) {

                ACPI_DEBUG_PRINT ((ACPI_DB_ERROR, "Needed Region, found type %X (%s)\n",

                        ACPI_GET_OBJECT_TYPE (rgn_desc),

                        acpi_ut_get_object_type_name (rgn_desc)));

                return_ACPI_STATUS (AE_AML_OPERAND_TYPE);

        }

        /*

         * If the Region Address and Length have not been previously evaluated,

         * evaluate them now and save the results.

         */

        if (!(rgn_desc->common.flags & AOPOBJ_DATA_VALID)) {

                status = acpi_ds_get_region_arguments (rgn_desc);

                if (ACPI_FAILURE (status)) {

                        return_ACPI_STATUS (status);

                }

        }

        if (rgn_desc->region.space_id == ACPI_ADR_SPACE_SMBUS) {

                /* SMBus has a non-linear address space */

                return_ACPI_STATUS (AE_OK);

        }

#ifdef ACPI_UNDER_DEVELOPMENT

        /*

         * If the Field access is any_acc, we can now compute the optimal

         * access (because we know know the length of the parent region)

         */

        if (!(obj_desc->common.flags & AOPOBJ_DATA_VALID)) {

                if (ACPI_FAILURE (status)) {

                        return_ACPI_STATUS (status);

                }

        }

#endif

        /*

         * Validate the request.  The entire request from the byte offset for a

         * length of one field datum (access width) must fit within the region.

         * (Region length is specified in bytes)

         */

        if (rgn_desc->region.length < (obj_desc->common_field.base_byte_offset

                           + field_datum_byte_offset

                           + obj_desc->common_field.access_byte_width)) {

                if (rgn_desc->region.length < obj_desc->common_field.access_byte_width) {

                        /*

                         * This is the case where the access_type (acc_word, etc.) is wider

                         * than the region itself.  For example, a region of length one

                         * byte, and a field with Dword access specified.

                         */

                        ACPI_DEBUG_PRINT ((ACPI_DB_ERROR,

                                "Field [%4.4s] access width (%d bytes) too large for region [%4.4s] (length %X)\n",

                                acpi_ut_get_node_name (obj_desc->common_field.node),

                                obj_desc->common_field.access_byte_width,

                                acpi_ut_get_node_name (rgn_desc->region.node), rgn_desc->region.length));

                }

                /*

                 * Offset rounded up to next multiple of field width

                 * exceeds region length, indicate an error

                 */

                ACPI_DEBUG_PRINT ((ACPI_DB_ERROR,

                        "Field [%4.4s] Base+Offset+Width %X+%X+%X is beyond end of region [%4.4s] (length %X)\n",

                        acpi_ut_get_node_name (obj_desc->common_field.node),

                        obj_desc->common_field.base_byte_offset,

                        field_datum_byte_offset, obj_desc->common_field.access_byte_width,

                        acpi_ut_get_node_name (rgn_desc->region.node), rgn_desc->region.length));

                if (!acpi_strict) {

                        /*

                         * Allow access to the field if it is within the region size

                         * rounded up to a multiple of the access byte width.  This

                         * overcomes "off-by-one" programming errors in the AML often

                         * found in Toshiba laptops.  These errors were allowed by

                         * the Microsoft ASL compiler.

                         */

                        u32 rounded_length = ACPI_ROUND_UP(rgn_desc->region.length,

                                                                        obj_desc->common_field.access_byte_width);

                        if (rounded_length < (obj_desc->common_field.base_byte_offset

                                                + field_datum_byte_offset

                                                + obj_desc->common_field.access_byte_width)) {

                                return_ACPI_STATUS (AE_AML_REGION_LIMIT);

                        } else {

                                static int      warn_once = 1;

                                if (warn_once) {

                                        // Could also associate a flag with each field, and

                                        // warn once for each field.

                                        ACPI_REPORT_WARNING((

                                                "The ACPI AML in your computer contains errors, "

                                                "please nag the manufacturer to correct it.\n"));

                                        ACPI_REPORT_WARNING((

                                                "Allowing relaxed access to fields; "

                                                "turn on CONFIG_ACPI_DEBUG for details.\n"));

                                        warn_once = 0;

                                }

                                return_ACPI_STATUS (AE_OK);

                        }

                }

                else {

                        return_ACPI_STATUS (AE_AML_REGION_LIMIT);

                }

        }

        return_ACPI_STATUS (AE_OK);

}

/*******************************************************************************

 *

 * FUNCTION:    acpi_ex_access_region

 *

 * PARAMETERS:  *obj_desc               - Field to be read

 *              field_datum_byte_offset - Byte offset of this datum within the

 *                                        parent field

 *              *Value                  - Where to store value (must at least

 *                                        the size of acpi_integer)

 *              Function                - Read or Write flag plus other region-

 *                                        dependent flags

 *

 * RETURN:      Status

 *

 * DESCRIPTION: Read or Write a single field datum to an Operation Region.

 *

 ******************************************************************************/

acpi_status

acpi_ex_access_region (

        union acpi_operand_object       *obj_desc,

        u32                             field_datum_byte_offset,

        acpi_integer                    *value,

        u32                             function)

{

        acpi_status                     status;

        union acpi_operand_object       *rgn_desc;

        acpi_physical_address           address;

        ACPI_FUNCTION_TRACE ("ex_access_region");

        /*

         * Ensure that the region operands are fully evaluated and verify

         * the validity of the request

         */

        status = acpi_ex_setup_region (obj_desc, field_datum_byte_offset);

        if (ACPI_FAILURE (status)) {

                return_ACPI_STATUS (status);

        }

        /*

         * The physical address of this field datum is:

         *

         * 1) The base of the region, plus

         * 2) The base offset of the field, plus

         * 3) The current offset into the field

         */

        rgn_desc = obj_desc->common_field.region_obj;

        address = rgn_desc->region.address

                         + obj_desc->common_field.base_byte_offset

                         + field_datum_byte_offset;

        if ((function & ACPI_IO_MASK) == ACPI_READ) {

                ACPI_DEBUG_PRINT ((ACPI_DB_BFIELD, "[READ]"));

        }

        else {

                ACPI_DEBUG_PRINT ((ACPI_DB_BFIELD, "[WRITE]"));

        }

        ACPI_DEBUG_PRINT_RAW ((ACPI_DB_BFIELD,

                " Region [%s:%X], Width %X, byte_base %X, Offset %X at %8.8X%8.8X\n",

                acpi_ut_get_region_name (rgn_desc->region.space_id),

                rgn_desc->region.space_id,

                obj_desc->common_field.access_byte_width,

                obj_desc->common_field.base_byte_offset,

                field_datum_byte_offset,

                ACPI_FORMAT_UINT64 (address)));

        /* Invoke the appropriate address_space/op_region handler */

        status = acpi_ev_address_space_dispatch (rgn_desc, function,

                          address, ACPI_MUL_8 (obj_desc->common_field.access_byte_width), value);

        if (ACPI_FAILURE (status)) {

                if (status == AE_NOT_IMPLEMENTED) {

                        ACPI_DEBUG_PRINT ((ACPI_DB_ERROR,

                                "Region %s(%X) not implemented\n",

                                acpi_ut_get_region_name (rgn_desc->region.space_id),

                                rgn_desc->region.space_id));

                }

                else if (status == AE_NOT_EXIST) {

                        ACPI_DEBUG_PRINT ((ACPI_DB_ERROR,

                                "Region %s(%X) has no handler\n",

                                acpi_ut_get_region_name (rgn_desc->region.space_id),

                                rgn_desc->region.space_id));

                }

        }

        return_ACPI_STATUS (status);

}

/*******************************************************************************

 *

 * FUNCTION:    acpi_ex_register_overflow

 *

 * PARAMETERS:  *obj_desc               - Register(Field) to be written

 *              Value                   - Value to be stored

 *

 * RETURN:      TRUE if value overflows the field, FALSE otherwise

 *

 * DESCRIPTION: Check if a value is out of range of the field being written.

 *              Used to check if the values written to Index and Bank registers

 *              are out of range.  Normally, the value is simply truncated

 *              to fit the field, but this case is most likely a serious

 *              coding error in the ASL.

 *

 ******************************************************************************/

u8

acpi_ex_register_overflow (

        union acpi_operand_object       *obj_desc,

        acpi_integer                    value)

{

        if (obj_desc->common_field.bit_length >= ACPI_INTEGER_BIT_SIZE) {

                /*

                 * The field is large enough to hold the maximum integer, so we can

                 * never overflow it.

                 */

                return (FALSE);

        }

        if (value >= ((acpi_integer) 1 << obj_desc->common_field.bit_length)) {

                /*

                 * The Value is larger than the maximum value that can fit into

                 * the register.

                 */

                return (TRUE);

        }

        /* The Value will fit into the field with no truncation */

        return (FALSE);

}

/*******************************************************************************

 *

 * FUNCTION:    acpi_ex_field_datum_io

 *

 * PARAMETERS:  *obj_desc               - Field to be read

 *              field_datum_byte_offset - Byte offset of this datum within the

 *                                        parent field

 *              *Value                  - Where to store value (must be 64 bits)

 *              read_write              - Read or Write flag

 *

 * RETURN:      Status

 *

 * DESCRIPTION: Read or Write a single datum of a field.  The field_type is

 *              demultiplexed here to handle the different types of fields

 *              (buffer_field, region_field, index_field, bank_field)

 *

 ******************************************************************************/

acpi_status

acpi_ex_field_datum_io (

        union acpi_operand_object       *obj_desc,

        u32                             field_datum_byte_offset,

        acpi_integer                    *value,

        u32                             read_write)

{

        acpi_status                     status;

        acpi_integer                    local_value;

        ACPI_FUNCTION_TRACE_U32 ("ex_field_datum_io", field_datum_byte_offset);

        if (read_write == ACPI_READ) {

                if (!value) {

                        local_value = 0;

                        value = &local_value; /* To support reads without saving return value */

                }

                /* Clear the entire return buffer first, [Very Important!] */

                *value = 0;

        }

        /*

         * The four types of fields are:

         *

         * buffer_field - Read/write from/to a Buffer

         * region_field - Read/write from/to a Operation Region.

         * bank_field  - Write to a Bank Register, then read/write from/to an op_region

         * index_field - Write to an Index Register, then read/write from/to a Data Register

         */

        switch (ACPI_GET_OBJECT_TYPE (obj_desc)) {

        case ACPI_TYPE_BUFFER_FIELD:

                /*

                 * If the buffer_field arguments have not been previously evaluated,

                 * evaluate them now and save the results.

                 */

                if (!(obj_desc->common.flags & AOPOBJ_DATA_VALID)) {

                        status = acpi_ds_get_buffer_field_arguments (obj_desc);

                        if (ACPI_FAILURE (status)) {

                                return_ACPI_STATUS (status);

                        }

                }

                if (read_write == ACPI_READ) {

                        /*

                         * Copy the data from the source buffer.

                         * Length is the field width in bytes.

                         */

                        ACPI_MEMCPY (value, (obj_desc->buffer_field.buffer_obj)->buffer.pointer

                                          + obj_desc->buffer_field.base_byte_offset

                                          + field_datum_byte_offset,

                                          obj_desc->common_field.access_byte_width);

                }

                else {

                        /*

                         * Copy the data to the target buffer.

                         * Length is the field width in bytes.

                         */

                        ACPI_MEMCPY ((obj_desc->buffer_field.buffer_obj)->buffer.pointer

                                        + obj_desc->buffer_field.base_byte_offset

                                        + field_datum_byte_offset,

                                        value, obj_desc->common_field.access_byte_width);

                }

                status = AE_OK;

                break;

        case ACPI_TYPE_LOCAL_BANK_FIELD:

                /* Ensure that the bank_value is not beyond the capacity of the register */

                if (acpi_ex_register_overflow (obj_desc->bank_field.bank_obj,

                                  (acpi_integer) obj_desc->bank_field.value)) {

                        return_ACPI_STATUS (AE_AML_REGISTER_LIMIT);

                }

                /*

                 * For bank_fields, we must write the bank_value to the bank_register

                 * (itself a region_field) before we can access the data.

                 */

                status = acpi_ex_insert_into_field (obj_desc->bank_field.bank_obj,

                                 &obj_desc->bank_field.value,

                                 sizeof (obj_desc->bank_field.value));

                if (ACPI_FAILURE (status)) {

                        return_ACPI_STATUS (status);

                }

                /*

                 * Now that the Bank has been selected, fall through to the

                 * region_field case and write the datum to the Operation Region

                 */

                /*lint -fallthrough */

        case ACPI_TYPE_LOCAL_REGION_FIELD:

                /*

                 * For simple region_fields, we just directly access the owning

                 * Operation Region.

                 */

                status = acpi_ex_access_region (obj_desc, field_datum_byte_offset, value,

                                  read_write);

                break;

        case ACPI_TYPE_LOCAL_INDEX_FIELD:

                /* Ensure that the index_value is not beyond the capacity of the register */

                if (acpi_ex_register_overflow (obj_desc->index_field.index_obj,

                                  (acpi_integer) obj_desc->index_field.value)) {

                        return_ACPI_STATUS (AE_AML_REGISTER_LIMIT);

                }

                /* Write the index value to the index_register (itself a region_field) */

                field_datum_byte_offset += obj_desc->index_field.value;

                ACPI_DEBUG_PRINT ((ACPI_DB_BFIELD,

                                "Write to Index Register: Value %8.8X\n",

                                field_datum_byte_offset));

                status = acpi_ex_insert_into_field (obj_desc->index_field.index_obj,

                                 &field_datum_byte_offset,

                                 sizeof (field_datum_byte_offset));

                if (ACPI_FAILURE (status)) {

                        return_ACPI_STATUS (status);

                }

                ACPI_DEBUG_PRINT ((ACPI_DB_BFIELD,

                                "I/O to Data Register: value_ptr %p\n",

                                value));

                if (read_write == ACPI_READ) {

                        /* Read the datum from the data_register */

                        status = acpi_ex_extract_from_field (obj_desc->index_field.data_obj,

                                          value, sizeof (acpi_integer));

                }

                else {

                        /* Write the datum to the data_register */

                        status = acpi_ex_insert_into_field (obj_desc->index_field.data_obj,

                                          value, sizeof (acpi_integer));

                }

                break;

        default:

                ACPI_REPORT_ERROR (("Wrong object type in field I/O %X\n",

                        ACPI_GET_OBJECT_TYPE (obj_desc)));

                status = AE_AML_INTERNAL;

                break;

        }

        if (ACPI_SUCCESS (status)) {

                if (read_write == ACPI_READ) {

                        ACPI_DEBUG_PRINT ((ACPI_DB_BFIELD, "Value Read %8.8X%8.8X, Width %d\n",

                                           ACPI_FORMAT_UINT64 (*value),

                                           obj_desc->common_field.access_byte_width));

                }

                else {

                        ACPI_DEBUG_PRINT ((ACPI_DB_BFIELD, "Value Written %8.8X%8.8X, Width %d\n",

                                           ACPI_FORMAT_UINT64 (*value),

                                           obj_desc->common_field.access_byte_width));

                }

        }

        return_ACPI_STATUS (status);

}

/*******************************************************************************

 *

 * FUNCTION:    acpi_ex_write_with_update_rule

 *

 * PARAMETERS:  *obj_desc           - Field to be set

 *              Value               - Value to store

 *

 * RETURN:      Status

 *

 * DESCRIPTION: Apply the field update rule to a field write

 *

 ******************************************************************************/

acpi_status

acpi_ex_write_with_update_rule (

        union acpi_operand_object       *obj_desc,

        acpi_integer                    mask,

        acpi_integer                    field_value,

        u32                             field_datum_byte_offset)

{

        acpi_status                     status = AE_OK;

        acpi_integer                    merged_value;

        acpi_integer                    current_value;

        ACPI_FUNCTION_TRACE_U32 ("ex_write_with_update_rule", mask);

        /* Start with the new bits  */

        merged_value = field_value;

        /* If the mask is all ones, we don't need to worry about the update rule */

        if (mask != ACPI_INTEGER_MAX) {

                /* Decode the update rule */

                switch (obj_desc->common_field.field_flags & AML_FIELD_UPDATE_RULE_MASK) {

                case AML_FIELD_UPDATE_PRESERVE:

                        /*

                         * Check if update rule needs to be applied (not if mask is all

                         * ones)  The left shift drops the bits we want to ignore.

                         */

                        if ((~mask << (ACPI_MUL_8 (sizeof (mask)) -

                                         ACPI_MUL_8 (obj_desc->common_field.access_byte_width))) != 0) {

                                /*

                                 * Read the current contents of the byte/word/dword containing

                                 * the field, and merge with the new field value.

                                 */

                                status = acpi_ex_field_datum_io (obj_desc, field_datum_byte_offset,

                                                  &current_value, ACPI_READ);

                                if (ACPI_FAILURE (status)) {

                                        return_ACPI_STATUS (status);

                                }

                                merged_value |= (current_value & ~mask);

                        }

                        break;

                case AML_FIELD_UPDATE_WRITE_AS_ONES:

                        /* Set positions outside the field to all ones */

                        merged_value |= ~mask;

                        break;

                case AML_FIELD_UPDATE_WRITE_AS_ZEROS:

                        /* Set positions outside the field to all zeros */

                        merged_value &= mask;

                        break;

                default:

                        ACPI_DEBUG_PRINT ((ACPI_DB_ERROR,

                                "write_with_update_rule: Unknown update_rule setting: %X\n",

                                (obj_desc->common_field.field_flags & AML_FIELD_UPDATE_RULE_MASK)));

                        return_ACPI_STATUS (AE_AML_OPERAND_VALUE);

                }

        }

        ACPI_DEBUG_PRINT ((ACPI_DB_BFIELD,

                "Mask %8.8X%8.8X, datum_offset %X, Width %X, Value %8.8X%8.8X, merged_value %8.8X%8.8X\n",

                ACPI_FORMAT_UINT64 (mask),

                field_datum_byte_offset,

                obj_desc->common_field.access_byte_width,

                ACPI_FORMAT_UINT64 (field_value),

                ACPI_FORMAT_UINT64 (merged_value)));

        /* Write the merged value */

        status = acpi_ex_field_datum_io (obj_desc, field_datum_byte_offset,

                          &merged_value, ACPI_WRITE);

        return_ACPI_STATUS (status);

}

/*******************************************************************************

 *

 * FUNCTION:    acpi_ex_get_buffer_datum

 *

 * PARAMETERS:  Datum               - Where the Datum is returned

 *              Buffer              - Raw field buffer

 *              buffer_length       - Entire length (used for big-endian only)

 *              byte_granularity    - 1/2/4/8 Granularity of the field

 *                                    (aka Datum Size)

 *              buffer_offset       - Datum offset into the buffer

 *

 * RETURN:      none

 *

 * DESCRIPTION: Get a datum from the buffer according to the buffer field

 *              byte granularity

 *

 ******************************************************************************/

void

acpi_ex_get_buffer_datum (

        acpi_integer                    *datum,

        void                            *buffer,

        u32                             buffer_length,

        u32                             byte_granularity,

        u32                             buffer_offset)

{

        u32                             index;

        ACPI_FUNCTION_TRACE_U32 ("ex_get_buffer_datum", byte_granularity);

        /* Get proper index into buffer (handles big/little endian) */

        index = ACPI_BUFFER_INDEX (buffer_length, buffer_offset, byte_granularity);

        /* Move the requested number of bytes */

        switch (byte_granularity) {

        case ACPI_FIELD_BYTE_GRANULARITY:

                *datum = ((u8 *) buffer) [index];

                break;

        case ACPI_FIELD_WORD_GRANULARITY:

                ACPI_MOVE_16_TO_64 (datum, &(((u16 *) buffer) [index]));

                break;

        case ACPI_FIELD_DWORD_GRANULARITY:

                ACPI_MOVE_32_TO_64 (datum, &(((u32 *) buffer) [index]));

                break;

        case ACPI_FIELD_QWORD_GRANULARITY:

                ACPI_MOVE_64_TO_64 (datum, &(((u64 *) buffer) [index]));

                break;

        default:

                /* Should not get here */

                break;

        }

        return_VOID;

}

/*******************************************************************************

 *

 * FUNCTION:    acpi_ex_set_buffer_datum

 *

 * PARAMETERS:  merged_datum        - Value to store

 *              Buffer              - Receiving buffer

 *              buffer_length       - Entire length (used for big-endian only)

 *              byte_granularity    - 1/2/4/8 Granularity of the field

 *                                    (aka Datum Size)

 *              buffer_offset       - Datum offset into the buffer

 *

 * RETURN:      none

 *

 * DESCRIPTION: Store the merged datum to the buffer according to the

 *              byte granularity

 *

 ******************************************************************************/

void

acpi_ex_set_buffer_datum (

        acpi_integer                    merged_datum,

        void                            *buffer,

        u32                             buffer_length,

        u32                             byte_granularity,

        u32                             buffer_offset)

{

        u32                             index;

        ACPI_FUNCTION_TRACE_U32 ("ex_set_buffer_datum", byte_granularity);

        /* Get proper index into buffer (handles big/little endian) */

        index = ACPI_BUFFER_INDEX (buffer_length, buffer_offset, byte_granularity);

        /* Move the requested number of bytes */

        switch (byte_granularity) {

        case ACPI_FIELD_BYTE_GRANULARITY:

                ((u8 *) buffer) [index] = (u8) merged_datum;

                break;

        case ACPI_FIELD_WORD_GRANULARITY:

                ACPI_MOVE_64_TO_16 (&(((u16 *) buffer)[index]), &merged_datum);

                break;

        case ACPI_FIELD_DWORD_GRANULARITY:

                ACPI_MOVE_64_TO_32 (&(((u32 *) buffer)[index]), &merged_datum);

                break;

        case ACPI_FIELD_QWORD_GRANULARITY:

                ACPI_MOVE_64_TO_64 (&(((u64 *) buffer)[index]), &merged_datum);

                break;

        default:

                /* Should not get here */

                break;

        }

        return_VOID;

}