/******************************************************************************
 *
 * Module Name: dsopcode - Dispatcher Op Region support and handling of
 *                         "control" opcodes
 *
 *****************************************************************************/

/*
 * 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/acparser.h>
#include <acpi/amlcode.h>
#include <acpi/acdispat.h>
#include <acpi/acinterp.h>
#include <acpi/acnamesp.h>
#include <acpi/acevents.h>

#define _COMPONENT          ACPI_DISPATCHER
         ACPI_MODULE_NAME    ("dsopcode")


/*****************************************************************************
 *
 * FUNCTION:    acpi_ds_execute_arguments
 *
 * PARAMETERS:  Node                - Parent NS node
 *              aml_length          - Length of executable AML
 *              aml_start           - Pointer to the AML
 *
 * RETURN:      Status.
 *
 * DESCRIPTION: Late (deferred) execution of region or field arguments
 *
 ****************************************************************************/

acpi_status
acpi_ds_execute_arguments (
        struct acpi_namespace_node      *node,
        struct acpi_namespace_node      *scope_node,
        u32                             aml_length,
        u8                              *aml_start)
{
        acpi_status                     status;
        union acpi_parse_object         *op;
        struct acpi_walk_state          *walk_state;


        ACPI_FUNCTION_TRACE ("ds_execute_arguments");


        /*
         * Allocate a new parser op to be the root of the parsed tree
         */
        op = acpi_ps_alloc_op (AML_INT_EVAL_SUBTREE_OP);
        if (!op) {
                return_ACPI_STATUS (AE_NO_MEMORY);
        }

        /* Save the Node for use in acpi_ps_parse_aml */

        op->common.node = scope_node;

        /* Create and initialize a new parser state */

        walk_state = acpi_ds_create_walk_state (0, NULL, NULL, NULL);
        if (!walk_state) {
                return_ACPI_STATUS (AE_NO_MEMORY);
        }

        status = acpi_ds_init_aml_walk (walk_state, op, NULL, aml_start,
                          aml_length, NULL, NULL, 1);
        if (ACPI_FAILURE (status)) {
                acpi_ds_delete_walk_state (walk_state);
                return_ACPI_STATUS (status);
        }

        /* Mark this parse as a deferred opcode */

        walk_state->parse_flags = ACPI_PARSE_DEFERRED_OP;
        walk_state->deferred_node = node;

        /* Pass1: Parse the entire declaration */

        status = acpi_ps_parse_aml (walk_state);
        if (ACPI_FAILURE (status)) {
                acpi_ps_delete_parse_tree (op);
                return_ACPI_STATUS (status);
        }

        /* Get and init the Op created above */

        op->common.node = node;
        acpi_ps_delete_parse_tree (op);

        /* Evaluate the deferred arguments */

        op = acpi_ps_alloc_op (AML_INT_EVAL_SUBTREE_OP);
        if (!op) {
                return_ACPI_STATUS (AE_NO_MEMORY);
        }

        op->common.node = scope_node;

        /* Create and initialize a new parser state */

        walk_state = acpi_ds_create_walk_state (0, NULL, NULL, NULL);
        if (!walk_state) {
                return_ACPI_STATUS (AE_NO_MEMORY);
        }

        /* Execute the opcode and arguments */

        status = acpi_ds_init_aml_walk (walk_state, op, NULL, aml_start,
                          aml_length, NULL, NULL, 3);
        if (ACPI_FAILURE (status)) {
                acpi_ds_delete_walk_state (walk_state);
                return_ACPI_STATUS (status);
        }

        /* Mark this execution as a deferred opcode */

        walk_state->deferred_node = node;
        status = acpi_ps_parse_aml (walk_state);
        acpi_ps_delete_parse_tree (op);
        return_ACPI_STATUS (status);
}


/*****************************************************************************
 *
 * FUNCTION:    acpi_ds_get_buffer_field_arguments
 *
 * PARAMETERS:  obj_desc        - A valid buffer_field object
 *
 * RETURN:      Status.
 *
 * DESCRIPTION: Get buffer_field Buffer and Index. This implements the late
 *              evaluation of these field attributes.
 *
 ****************************************************************************/

acpi_status
acpi_ds_get_buffer_field_arguments (
        union acpi_operand_object       *obj_desc)
{
        union acpi_operand_object       *extra_desc;
        struct acpi_namespace_node      *node;
        acpi_status                     status;


        ACPI_FUNCTION_TRACE_PTR ("ds_get_buffer_field_arguments", obj_desc);


        if (obj_desc->common.flags & AOPOBJ_DATA_VALID) {
                return_ACPI_STATUS (AE_OK);
        }

        /* Get the AML pointer (method object) and buffer_field node */

        extra_desc = acpi_ns_get_secondary_object (obj_desc);
        node = obj_desc->buffer_field.node;

        ACPI_DEBUG_EXEC(acpi_ut_display_init_pathname (ACPI_TYPE_BUFFER_FIELD, node, NULL));
        ACPI_DEBUG_PRINT ((ACPI_DB_EXEC, "[%4.4s] buffer_field Arg Init\n",
                acpi_ut_get_node_name (node)));

        /* Execute the AML code for the term_arg arguments */

        status = acpi_ds_execute_arguments (node, acpi_ns_get_parent_node (node),
                         extra_desc->extra.aml_length, extra_desc->extra.aml_start);
        return_ACPI_STATUS (status);
}


/*****************************************************************************
 *
 * FUNCTION:    acpi_ds_get_buffer_arguments
 *
 * PARAMETERS:  obj_desc        - A valid Buffer object
 *
 * RETURN:      Status.
 *
 * DESCRIPTION: Get Buffer length and initializer byte list.  This implements
 *              the late evaluation of these attributes.
 *
 ****************************************************************************/

acpi_status
acpi_ds_get_buffer_arguments (
        union acpi_operand_object       *obj_desc)
{
        struct acpi_namespace_node      *node;
        acpi_status                     status;


        ACPI_FUNCTION_TRACE_PTR ("ds_get_buffer_arguments", obj_desc);


        if (obj_desc->common.flags & AOPOBJ_DATA_VALID) {
                return_ACPI_STATUS (AE_OK);
        }

        /* Get the Buffer node */

        node = obj_desc->buffer.node;
        if (!node) {
                ACPI_REPORT_ERROR ((
                                "No pointer back to NS node in buffer obj %p\n", obj_desc));
                return_ACPI_STATUS (AE_AML_INTERNAL);
        }

        ACPI_DEBUG_PRINT ((ACPI_DB_EXEC, "Buffer Arg Init\n"));

        /* Execute the AML code for the term_arg arguments */

        status = acpi_ds_execute_arguments (node, node,
                         obj_desc->buffer.aml_length, obj_desc->buffer.aml_start);
        return_ACPI_STATUS (status);
}


/*****************************************************************************
 *
 * FUNCTION:    acpi_ds_get_package_arguments
 *
 * PARAMETERS:  obj_desc        - A valid Package object
 *
 * RETURN:      Status.
 *
 * DESCRIPTION: Get Package length and initializer byte list.  This implements
 *              the late evaluation of these attributes.
 *
 ****************************************************************************/

acpi_status
acpi_ds_get_package_arguments (
        union acpi_operand_object       *obj_desc)
{
        struct acpi_namespace_node      *node;
        acpi_status                     status;


        ACPI_FUNCTION_TRACE_PTR ("ds_get_package_arguments", obj_desc);


        if (obj_desc->common.flags & AOPOBJ_DATA_VALID) {
                return_ACPI_STATUS (AE_OK);
        }

        /* Get the Package node */

        node = obj_desc->package.node;
        if (!node) {
                ACPI_REPORT_ERROR ((
                                "No pointer back to NS node in package %p\n", obj_desc));
                return_ACPI_STATUS (AE_AML_INTERNAL);
        }

        ACPI_DEBUG_PRINT ((ACPI_DB_EXEC, "Package Arg Init\n"));

        /* Execute the AML code for the term_arg arguments */

        status = acpi_ds_execute_arguments (node, node,
                         obj_desc->package.aml_length, obj_desc->package.aml_start);
        return_ACPI_STATUS (status);
}


/*****************************************************************************
 *
 * FUNCTION:    acpi_ds_get_region_arguments
 *
 * PARAMETERS:  obj_desc        - A valid region object
 *
 * RETURN:      Status.
 *
 * DESCRIPTION: Get region address and length.  This implements the late
 *              evaluation of these region attributes.
 *
 ****************************************************************************/

acpi_status
acpi_ds_get_region_arguments (
        union acpi_operand_object       *obj_desc)
{
        struct acpi_namespace_node      *node;
        acpi_status                     status;
        union acpi_operand_object       *extra_desc;


        ACPI_FUNCTION_TRACE_PTR ("ds_get_region_arguments", obj_desc);


        if (obj_desc->region.flags & AOPOBJ_DATA_VALID) {
                return_ACPI_STATUS (AE_OK);
        }

        extra_desc = acpi_ns_get_secondary_object (obj_desc);
        if (!extra_desc) {
                return_ACPI_STATUS (AE_NOT_EXIST);
        }

        /* Get the Region node */

        node = obj_desc->region.node;

        ACPI_DEBUG_EXEC (acpi_ut_display_init_pathname (ACPI_TYPE_REGION, node, NULL));

        ACPI_DEBUG_PRINT ((ACPI_DB_EXEC, "[%4.4s] op_region Arg Init at AML %p\n",
                acpi_ut_get_node_name (node), extra_desc->extra.aml_start));

        /* Execute the argument AML */

        status = acpi_ds_execute_arguments (node, acpi_ns_get_parent_node (node),
                         extra_desc->extra.aml_length, extra_desc->extra.aml_start);
        return_ACPI_STATUS (status);
}


/*****************************************************************************
 *
 * FUNCTION:    acpi_ds_initialize_region
 *
 * PARAMETERS:  Op              - A valid region Op object
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Front end to ev_initialize_region
 *
 ****************************************************************************/

acpi_status
acpi_ds_initialize_region (
        acpi_handle                     obj_handle)
{
        union acpi_operand_object       *obj_desc;
        acpi_status                     status;


        obj_desc = acpi_ns_get_attached_object (obj_handle);

        /* Namespace is NOT locked */

        status = acpi_ev_initialize_region (obj_desc, FALSE);
        return (status);
}


/*****************************************************************************
 *
 * FUNCTION:    acpi_ds_init_buffer_field
 *
 * PARAMETERS:  aml_opcode      - create_xxx_field
 *              obj_desc        - buffer_field object
 *              buffer_desc     - Host Buffer
 *              offset_desc     - Offset into buffer
 *              Length          - Length of field (CREATE_FIELD_OP only)
 *              Result          - Where to store the result
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Perform actual initialization of a buffer field
 *
 ****************************************************************************/

acpi_status
acpi_ds_init_buffer_field (
        u16                             aml_opcode,
        union acpi_operand_object       *obj_desc,
        union acpi_operand_object       *buffer_desc,
        union acpi_operand_object       *offset_desc,
        union acpi_operand_object       *length_desc,
        union acpi_operand_object       *result_desc)
{
        u32                             offset;
        u32                             bit_offset;
        u32                             bit_count;
        u8                              field_flags;
        acpi_status                     status;


        ACPI_FUNCTION_TRACE_PTR ("ds_init_buffer_field", obj_desc);


        /* Host object must be a Buffer */

        if (ACPI_GET_OBJECT_TYPE (buffer_desc) != ACPI_TYPE_BUFFER) {
                ACPI_DEBUG_PRINT ((ACPI_DB_ERROR,
                        "Target of Create Field is not a Buffer object - %s\n",
                        acpi_ut_get_object_type_name (buffer_desc)));

                status = AE_AML_OPERAND_TYPE;
                goto cleanup;
        }

        /*
         * The last parameter to all of these opcodes (result_desc) started
         * out as a name_string, and should therefore now be a NS node
         * after resolution in acpi_ex_resolve_operands().
         */
        if (ACPI_GET_DESCRIPTOR_TYPE (result_desc) != ACPI_DESC_TYPE_NAMED) {
                ACPI_DEBUG_PRINT ((ACPI_DB_ERROR, "(%s) destination not a NS Node [%s]\n",
                                acpi_ps_get_opcode_name (aml_opcode), acpi_ut_get_descriptor_name (result_desc)));

                status = AE_AML_OPERAND_TYPE;
                goto cleanup;
        }

        offset = (u32) offset_desc->integer.value;

        /*
         * Setup the Bit offsets and counts, according to the opcode
         */
        switch (aml_opcode) {
        case AML_CREATE_FIELD_OP:

                /* Offset is in bits, count is in bits */

                bit_offset = offset;
                bit_count  = (u32) length_desc->integer.value;
                field_flags = AML_FIELD_ACCESS_BYTE;
                break;

        case AML_CREATE_BIT_FIELD_OP:

                /* Offset is in bits, Field is one bit */

                bit_offset = offset;
                bit_count  = 1;
                field_flags = AML_FIELD_ACCESS_BYTE;
                break;

        case AML_CREATE_BYTE_FIELD_OP:

                /* Offset is in bytes, field is one byte */

                bit_offset = 8 * offset;
                bit_count  = 8;
                field_flags = AML_FIELD_ACCESS_BYTE;
                break;

        case AML_CREATE_WORD_FIELD_OP:

                /* Offset is in bytes, field is one word */

                bit_offset = 8 * offset;
                bit_count  = 16;
                field_flags = AML_FIELD_ACCESS_WORD;
                break;

        case AML_CREATE_DWORD_FIELD_OP:

                /* Offset is in bytes, field is one dword */

                bit_offset = 8 * offset;
                bit_count  = 32;
                field_flags = AML_FIELD_ACCESS_DWORD;
                break;

        case AML_CREATE_QWORD_FIELD_OP:

                /* Offset is in bytes, field is one qword */

                bit_offset = 8 * offset;
                bit_count  = 64;
                field_flags = AML_FIELD_ACCESS_QWORD;
                break;

        default:

                ACPI_DEBUG_PRINT ((ACPI_DB_ERROR,
                        "Unknown field creation opcode %02x\n",
                        aml_opcode));
                status = AE_AML_BAD_OPCODE;
                goto cleanup;
        }

        /* Entire field must fit within the current length of the buffer */

        if ((bit_offset + bit_count) >
                (8 * (u32) buffer_desc->buffer.length)) {
                ACPI_DEBUG_PRINT ((ACPI_DB_ERROR,
                        "Field [%4.4s] size %d exceeds Buffer [%4.4s] size %d (bits)\n",
                         acpi_ut_get_node_name (result_desc),
                         bit_offset + bit_count,
                         acpi_ut_get_node_name (buffer_desc->buffer.node),
                         8 * (u32) buffer_desc->buffer.length));
                status = AE_AML_BUFFER_LIMIT;
                goto cleanup;
        }

        /*
         * Initialize areas of the field object that are common to all fields
         * For field_flags, use LOCK_RULE = 0 (NO_LOCK), UPDATE_RULE = 0 (UPDATE_PRESERVE)
         */
        status = acpi_ex_prep_common_field_object (obj_desc, field_flags, 0,
                          bit_offset, bit_count);
        if (ACPI_FAILURE (status)) {
                goto cleanup;
        }

        obj_desc->buffer_field.buffer_obj = buffer_desc;

        /* Reference count for buffer_desc inherits obj_desc count */

        buffer_desc->common.reference_count = (u16) (buffer_desc->common.reference_count +
                          obj_desc->common.reference_count);


cleanup:

        /* Always delete the operands */

        acpi_ut_remove_reference (offset_desc);
        acpi_ut_remove_reference (buffer_desc);

        if (aml_opcode == AML_CREATE_FIELD_OP) {
                acpi_ut_remove_reference (length_desc);
        }

        /* On failure, delete the result descriptor */

        if (ACPI_FAILURE (status)) {
                acpi_ut_remove_reference (result_desc); /* Result descriptor */
        }
        else {
                /* Now the address and length are valid for this buffer_field */

                obj_desc->buffer_field.flags |= AOPOBJ_DATA_VALID;
        }

        return_ACPI_STATUS (status);
}


/*****************************************************************************
 *
 * FUNCTION:    acpi_ds_eval_buffer_field_operands
 *
 * PARAMETERS:  walk_state      - Current walk
 *              Op              - A valid buffer_field Op object
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Get buffer_field Buffer and Index
 *              Called from acpi_ds_exec_end_op during buffer_field parse tree walk
 *
 ****************************************************************************/

acpi_status
acpi_ds_eval_buffer_field_operands (
        struct acpi_walk_state          *walk_state,
        union acpi_parse_object         *op)
{
        acpi_status                     status;
        union acpi_operand_object       *obj_desc;
        struct acpi_namespace_node      *node;
        union acpi_parse_object         *next_op;


        ACPI_FUNCTION_TRACE_PTR ("ds_eval_buffer_field_operands", op);


        /*
         * This is where we evaluate the address and length fields of the
         * create_xxx_field declaration
         */
        node =  op->common.node;

        /* next_op points to the op that holds the Buffer */

        next_op = op->common.value.arg;

        /* Evaluate/create the address and length operands */

        status = acpi_ds_create_operands (walk_state, next_op);
        if (ACPI_FAILURE (status)) {
                return_ACPI_STATUS (status);
        }

        obj_desc = acpi_ns_get_attached_object (node);
        if (!obj_desc) {
                return_ACPI_STATUS (AE_NOT_EXIST);
        }

        /* Resolve the operands */

        status = acpi_ex_resolve_operands (op->common.aml_opcode,
                          ACPI_WALK_OPERANDS, walk_state);

        ACPI_DUMP_OPERANDS (ACPI_WALK_OPERANDS, ACPI_IMODE_EXECUTE,
                          acpi_ps_get_opcode_name (op->common.aml_opcode),
                          walk_state->num_operands, "after acpi_ex_resolve_operands");

        if (ACPI_FAILURE (status)) {
                ACPI_DEBUG_PRINT ((ACPI_DB_ERROR, "(%s) bad operand(s) (%X)\n",
                        acpi_ps_get_opcode_name (op->common.aml_opcode), status));

                return_ACPI_STATUS (status);
        }

        /* Initialize the Buffer Field */

        if (op->common.aml_opcode == AML_CREATE_FIELD_OP) {
                /* NOTE: Slightly different operands for this opcode */

                status = acpi_ds_init_buffer_field (op->common.aml_opcode, obj_desc,
                                 walk_state->operands[0], walk_state->operands[1],
                                 walk_state->operands[2], walk_state->operands[3]);
        }
        else {
                /* All other, create_xxx_field opcodes */

                status = acpi_ds_init_buffer_field (op->common.aml_opcode, obj_desc,
                                 walk_state->operands[0], walk_state->operands[1],
                                                  NULL, walk_state->operands[2]);
        }

        return_ACPI_STATUS (status);
}


/*****************************************************************************
 *
 * FUNCTION:    acpi_ds_eval_region_operands
 *
 * PARAMETERS:  walk_state      - Current walk
 *              Op              - A valid region Op object
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Get region address and length
 *              Called from acpi_ds_exec_end_op during op_region parse tree walk
 *
 ****************************************************************************/

acpi_status
acpi_ds_eval_region_operands (
        struct acpi_walk_state          *walk_state,
        union acpi_parse_object         *op)
{
        acpi_status                     status;
        union acpi_operand_object       *obj_desc;
        union acpi_operand_object       *operand_desc;
        struct acpi_namespace_node      *node;
        union acpi_parse_object         *next_op;


        ACPI_FUNCTION_TRACE_PTR ("ds_eval_region_operands", op);


        /*
         * This is where we evaluate the address and length fields of the op_region declaration
         */
        node =  op->common.node;

        /* next_op points to the op that holds the space_iD */

        next_op = op->common.value.arg;

        /* next_op points to address op */

        next_op = next_op->common.next;

        /* Evaluate/create the address and length operands */

        status = acpi_ds_create_operands (walk_state, next_op);
        if (ACPI_FAILURE (status)) {
                return_ACPI_STATUS (status);
        }

        /* Resolve the length and address operands to numbers */

        status = acpi_ex_resolve_operands (op->common.aml_opcode, ACPI_WALK_OPERANDS, walk_state);
        if (ACPI_FAILURE (status)) {
                return_ACPI_STATUS (status);
        }

        ACPI_DUMP_OPERANDS (ACPI_WALK_OPERANDS, ACPI_IMODE_EXECUTE,
                          acpi_ps_get_opcode_name (op->common.aml_opcode),
                          1, "after acpi_ex_resolve_operands");

        obj_desc = acpi_ns_get_attached_object (node);
        if (!obj_desc) {
                return_ACPI_STATUS (AE_NOT_EXIST);
        }

        /*
         * Get the length operand and save it
         * (at Top of stack)
         */
        operand_desc = walk_state->operands[walk_state->num_operands - 1];

        obj_desc->region.length = (u32) operand_desc->integer.value;
        acpi_ut_remove_reference (operand_desc);

        /*
         * Get the address and save it
         * (at top of stack - 1)
         */
        operand_desc = walk_state->operands[walk_state->num_operands - 2];

        obj_desc->region.address = (acpi_physical_address) operand_desc->integer.value;
        acpi_ut_remove_reference (operand_desc);

        ACPI_DEBUG_PRINT ((ACPI_DB_EXEC, "rgn_obj %p Addr %8.8X%8.8X Len %X\n",
                obj_desc,
                ACPI_FORMAT_UINT64 (obj_desc->region.address),
                obj_desc->region.length));

        /* Now the address and length are valid for this opregion */

        obj_desc->region.flags |= AOPOBJ_DATA_VALID;

        return_ACPI_STATUS (status);
}


/*****************************************************************************
 *
 * FUNCTION:    acpi_ds_eval_data_object_operands
 *
 * PARAMETERS:  walk_state      - Current walk
 *              Op              - A valid data_object Op object
 *              obj_desc        - data_object
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Get the operands and complete the following data objec types:
 *              Buffer
 *              Package
 *
 ****************************************************************************/

acpi_status
acpi_ds_eval_data_object_operands (
        struct acpi_walk_state          *walk_state,
        union acpi_parse_object         *op,
        union acpi_operand_object       *obj_desc)
{
        acpi_status                     status;
        union acpi_operand_object       *arg_desc;
        u32                             length;


        ACPI_FUNCTION_TRACE ("ds_eval_data_object_operands");


        /* The first operand (for all of these data objects) is the length */

        status = acpi_ds_create_operand (walk_state, op->common.value.arg, 1);
        if (ACPI_FAILURE (status)) {
                return_ACPI_STATUS (status);
        }

        status = acpi_ex_resolve_operands (walk_state->opcode,
                          &(walk_state->operands [walk_state->num_operands -1]),
                          walk_state);
        if (ACPI_FAILURE (status)) {
                return_ACPI_STATUS (status);
        }

        /* Extract length operand */

        arg_desc = walk_state->operands [walk_state->num_operands - 1];
        length = (u32) arg_desc->integer.value;

        /* Cleanup for length operand */

        status = acpi_ds_obj_stack_pop (1, walk_state);
        if (ACPI_FAILURE (status)) {
                return_ACPI_STATUS (status);
        }

        acpi_ut_remove_reference (arg_desc);

        /*
         * Create the actual data object
         */
        switch (op->common.aml_opcode) {
        case AML_BUFFER_OP:

                status = acpi_ds_build_internal_buffer_obj (walk_state, op, length, &obj_desc);
                break;

        case AML_PACKAGE_OP:
        case AML_VAR_PACKAGE_OP:

                status = acpi_ds_build_internal_package_obj (walk_state, op, length, &obj_desc);
                break;

        default:
                return_ACPI_STATUS (AE_AML_BAD_OPCODE);
        }

        if (ACPI_SUCCESS (status)) {
                /*
                 * Return the object in the walk_state, unless the parent is a package --
                 * in this case, the return object will be stored in the parse tree
                 * for the package.
                 */
                if ((!op->common.parent) ||
                        ((op->common.parent->common.aml_opcode != AML_PACKAGE_OP) &&
                         (op->common.parent->common.aml_opcode != AML_VAR_PACKAGE_OP) &&
                         (op->common.parent->common.aml_opcode != AML_NAME_OP))) {
                        walk_state->result_obj = obj_desc;
                }
        }

        return_ACPI_STATUS (status);
}


/*******************************************************************************
 *
 * FUNCTION:    acpi_ds_exec_begin_control_op
 *
 * PARAMETERS:  walk_list       - The list that owns the walk stack
 *              Op              - The control Op
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Handles all control ops encountered during control method
 *              execution.
 *
 ******************************************************************************/

acpi_status
acpi_ds_exec_begin_control_op (
        struct acpi_walk_state          *walk_state,
        union acpi_parse_object         *op)
{
        acpi_status                     status = AE_OK;
        union acpi_generic_state        *control_state;


        ACPI_FUNCTION_NAME ("ds_exec_begin_control_op");


        ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH, "Op=%p Opcode=%2.2X State=%p\n", op,
                op->common.aml_opcode, walk_state));

        switch (op->common.aml_opcode) {
        case AML_IF_OP:
        case AML_WHILE_OP:

                /*
                 * IF/WHILE: Create a new control state to manage these
                 * constructs. We need to manage these as a stack, in order
                 * to handle nesting.
                 */
                control_state = acpi_ut_create_control_state ();
                if (!control_state) {
                        status = AE_NO_MEMORY;
                        break;
                }
                /*
                 * Save a pointer to the predicate for multiple executions
                 * of a loop
                 */
                control_state->control.aml_predicate_start = walk_state->parser_state.aml - 1;
                control_state->control.package_end = walk_state->parser_state.pkg_end;
                control_state->control.opcode = op->common.aml_opcode;


                /* Push the control state on this walk's control stack */

                acpi_ut_push_generic_state (&walk_state->control_state, control_state);
                break;

        case AML_ELSE_OP:

                /* Predicate is in the state object */
                /* If predicate is true, the IF was executed, ignore ELSE part */

                if (walk_state->last_predicate) {
                        status = AE_CTRL_TRUE;
                }

                break;

        case AML_RETURN_OP:

                break;

        default:
                break;
        }

        return (status);
}


/*******************************************************************************
 *
 * FUNCTION:    acpi_ds_exec_end_control_op
 *
 * PARAMETERS:  walk_list       - The list that owns the walk stack
 *              Op              - The control Op
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Handles all control ops encountered during control method
 *              execution.
 *
 ******************************************************************************/

acpi_status
acpi_ds_exec_end_control_op (
        struct acpi_walk_state          *walk_state,
        union acpi_parse_object         *op)
{
        acpi_status                     status = AE_OK;
        union acpi_generic_state        *control_state;


        ACPI_FUNCTION_NAME ("ds_exec_end_control_op");


        switch (op->common.aml_opcode) {
        case AML_IF_OP:

                ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH, "[IF_OP] Op=%p\n", op));

                /*
                 * Save the result of the predicate in case there is an
                 * ELSE to come
                 */
                walk_state->last_predicate =
                        (u8) walk_state->control_state->common.value;

                /*
                 * Pop the control state that was created at the start
                 * of the IF and free it
                 */
                control_state = acpi_ut_pop_generic_state (&walk_state->control_state);
                acpi_ut_delete_generic_state (control_state);
                break;


        case AML_ELSE_OP:

                break;


        case AML_WHILE_OP:

                ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH, "[WHILE_OP] Op=%p\n", op));

                if (walk_state->control_state->common.value) {
                        /* Predicate was true, go back and evaluate it again! */

                        status = AE_CTRL_PENDING;
                }

                ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH, "[WHILE_OP] termination! Op=%p\n", op));

                /* Pop this control state and free it */

                control_state = acpi_ut_pop_generic_state (&walk_state->control_state);

                walk_state->aml_last_while = control_state->control.aml_predicate_start;
                acpi_ut_delete_generic_state (control_state);
                break;

        case AML_RETURN_OP:

                ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH,
                        "[RETURN_OP] Op=%p Arg=%p\n",op, op->common.value.arg));

                /*
                 * One optional operand -- the return value
                 * It can be either an immediate operand or a result that
                 * has been bubbled up the tree
                 */
                if (op->common.value.arg) {
                        /* Return statement has an immediate operand */

                        status = acpi_ds_create_operands (walk_state, op->common.value.arg);
                        if (ACPI_FAILURE (status)) {
                                return (status);
                        }

                        /*
                         * If value being returned is a Reference (such as
                         * an arg or local), resolve it now because it may
                         * cease to exist at the end of the method.
                         */
                        status = acpi_ex_resolve_to_value (&walk_state->operands [0], walk_state);
                        if (ACPI_FAILURE (status)) {
                                return (status);
                        }

                        /*
                         * Get the return value and save as the last result
                         * value.  This is the only place where walk_state->return_desc
                         * is set to anything other than zero!
                         */
                        walk_state->return_desc = walk_state->operands[0];
                }
                else if ((walk_state->results) &&
                                 (walk_state->results->results.num_results > 0)) {
                        /*
                         * The return value has come from a previous calculation.
                         *
                         * If value being returned is a Reference (such as
                         * an arg or local), resolve it now because it may
                         * cease to exist at the end of the method.
                         *
                         * Allow references created by the Index operator to return unchanged.
                         */
                        if ((ACPI_GET_DESCRIPTOR_TYPE (walk_state->results->results.obj_desc[0]) == ACPI_DESC_TYPE_OPERAND) &&
                                (ACPI_GET_OBJECT_TYPE (walk_state->results->results.obj_desc [0]) == ACPI_TYPE_LOCAL_REFERENCE) &&
                                ((walk_state->results->results.obj_desc [0])->reference.opcode != AML_INDEX_OP)) {
                                status = acpi_ex_resolve_to_value (&walk_state->results->results.obj_desc [0], walk_state);
                                if (ACPI_FAILURE (status)) {
                                        return (status);
                                }
                        }

                        walk_state->return_desc = walk_state->results->results.obj_desc [0];
                }
                else {
                        /* No return operand */

                        if (walk_state->num_operands) {
                                acpi_ut_remove_reference (walk_state->operands [0]);
                        }

                        walk_state->operands [0]    = NULL;
                        walk_state->num_operands    = 0;
                        walk_state->return_desc     = NULL;
                }


                ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH,
                        "Completed RETURN_OP State=%p, ret_val=%p\n",
                        walk_state, walk_state->return_desc));

                /* End the control method execution right now */

                status = AE_CTRL_TERMINATE;
                break;


        case AML_NOOP_OP:

                /* Just do nothing! */
                break;


        case AML_BREAK_POINT_OP:

                /* Call up to the OS service layer to handle this */

                status = acpi_os_signal (ACPI_SIGNAL_BREAKPOINT, "Executed AML Breakpoint opcode");

                /* If and when it returns, all done. */

                break;


        case AML_BREAK_OP:
        case AML_CONTINUE_OP: /* ACPI 2.0 */


                /* Pop and delete control states until we find a while */

                while (walk_state->control_state &&
                                (walk_state->control_state->control.opcode != AML_WHILE_OP)) {
                        control_state = acpi_ut_pop_generic_state (&walk_state->control_state);
                        acpi_ut_delete_generic_state (control_state);
                }

                /* No while found? */

                if (!walk_state->control_state) {
                        return (AE_AML_NO_WHILE);
                }

                /* Was: walk_state->aml_last_while = walk_state->control_state->Control.aml_predicate_start; */

                walk_state->aml_last_while = walk_state->control_state->control.package_end;

                /* Return status depending on opcode */

                if (op->common.aml_opcode == AML_BREAK_OP) {
                        status = AE_CTRL_BREAK;
                }
                else {
                        status = AE_CTRL_CONTINUE;
                }
                break;


        default:

                ACPI_DEBUG_PRINT ((ACPI_DB_ERROR, "Unknown control opcode=%X Op=%p\n",
                        op->common.aml_opcode, op));

                status = AE_AML_BAD_OPCODE;
                break;
        }

        return (status);
}