/******************************************************************************
 *
 * Module Name: psloop - Main AML parse loop
 *
 *****************************************************************************/

/*
 * Copyright (C) 2000 - 2008, Intel Corp.
 * 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.
 */

/*
 * Parse the AML and build an operation tree as most interpreters, (such as
 * Perl) do. Parsing is done by hand rather than with a YACC generated parser
 * to tightly constrain stack and dynamic memory usage. Parsing is kept
 * flexible and the code fairly compact by parsing based on a list of AML
 * opcode templates in aml_op_info[].
 */

#include <acpi/acpi.h>
#include "accommon.h"
#include "acparser.h"
#include "acdispat.h"
#include "amlcode.h"

#define _COMPONENT          ACPI_PARSER
ACPI_MODULE_NAME("psloop")

static u32 acpi_gbl_depth = 0;

/* Local prototypes */

static acpi_status acpi_ps_get_aml_opcode(struct acpi_walk_state *walk_state);

static acpi_status
acpi_ps_build_named_op(struct acpi_walk_state *walk_state,
                       u8 * aml_op_start,
                       union acpi_parse_object *unnamed_op,
                       union acpi_parse_object **op);

static acpi_status
acpi_ps_create_op(struct acpi_walk_state *walk_state,
                  u8 * aml_op_start, union acpi_parse_object **new_op);

static acpi_status
acpi_ps_get_arguments(struct acpi_walk_state *walk_state,
                      u8 * aml_op_start, union acpi_parse_object *op);

static acpi_status
acpi_ps_complete_op(struct acpi_walk_state *walk_state,
                    union acpi_parse_object **op, acpi_status status);

static acpi_status
acpi_ps_complete_final_op(struct acpi_walk_state *walk_state,
                          union acpi_parse_object *op, acpi_status status);

static void
acpi_ps_link_module_code(u8 *aml_start, u32 aml_length, acpi_owner_id owner_id);

/*******************************************************************************
 *
 * FUNCTION:    acpi_ps_get_aml_opcode
 *
 * PARAMETERS:  walk_state          - Current state
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Extract the next AML opcode from the input stream.
 *
 ******************************************************************************/

static acpi_status acpi_ps_get_aml_opcode(struct acpi_walk_state *walk_state)
{

        ACPI_FUNCTION_TRACE_PTR(ps_get_aml_opcode, walk_state);

        walk_state->aml_offset =
            (u32) ACPI_PTR_DIFF(walk_state->parser_state.aml,
                                walk_state->parser_state.aml_start);
        walk_state->opcode = acpi_ps_peek_opcode(&(walk_state->parser_state));

        /*
         * First cut to determine what we have found:
         * 1) A valid AML opcode
         * 2) A name string
         * 3) An unknown/invalid opcode
         */
        walk_state->op_info = acpi_ps_get_opcode_info(walk_state->opcode);

        switch (walk_state->op_info->class) {
        case AML_CLASS_ASCII:
        case AML_CLASS_PREFIX:
                /*
                 * Starts with a valid prefix or ASCII char, this is a name
                 * string. Convert the bare name string to a namepath.
                 */
                walk_state->opcode = AML_INT_NAMEPATH_OP;
                walk_state->arg_types = ARGP_NAMESTRING;
                break;

        case AML_CLASS_UNKNOWN:

                /* The opcode is unrecognized. Just skip unknown opcodes */

                ACPI_ERROR((AE_INFO,
                            "Found unknown opcode %X at AML address %p offset %X, ignoring",
                            walk_state->opcode, walk_state->parser_state.aml,
                            walk_state->aml_offset));

                ACPI_DUMP_BUFFER(walk_state->parser_state.aml, 128);

                /* Assume one-byte bad opcode */

                walk_state->parser_state.aml++;
                return_ACPI_STATUS(AE_CTRL_PARSE_CONTINUE);

        default:

                /* Found opcode info, this is a normal opcode */

                walk_state->parser_state.aml +=
                    acpi_ps_get_opcode_size(walk_state->opcode);
                walk_state->arg_types = walk_state->op_info->parse_args;
                break;
        }

        return_ACPI_STATUS(AE_OK);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ps_build_named_op
 *
 * PARAMETERS:  walk_state          - Current state
 *              aml_op_start        - Begin of named Op in AML
 *              unnamed_op          - Early Op (not a named Op)
 *              Op                  - Returned Op
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Parse a named Op
 *
 ******************************************************************************/

static acpi_status
acpi_ps_build_named_op(struct acpi_walk_state *walk_state,
                       u8 * aml_op_start,
                       union acpi_parse_object *unnamed_op,
                       union acpi_parse_object **op)
{
        acpi_status status = AE_OK;
        union acpi_parse_object *arg = NULL;

        ACPI_FUNCTION_TRACE_PTR(ps_build_named_op, walk_state);

        unnamed_op->common.value.arg = NULL;
        unnamed_op->common.arg_list_length = 0;
        unnamed_op->common.aml_opcode = walk_state->opcode;

        /*
         * Get and append arguments until we find the node that contains
         * the name (the type ARGP_NAME).
         */
        while (GET_CURRENT_ARG_TYPE(walk_state->arg_types) &&
               (GET_CURRENT_ARG_TYPE(walk_state->arg_types) != ARGP_NAME)) {
                status =
                    acpi_ps_get_next_arg(walk_state,
                                         &(walk_state->parser_state),
                                         GET_CURRENT_ARG_TYPE(walk_state->
                                                              arg_types), &arg);
                if (ACPI_FAILURE(status)) {
                        return_ACPI_STATUS(status);
                }

                acpi_ps_append_arg(unnamed_op, arg);
                INCREMENT_ARG_LIST(walk_state->arg_types);
        }

        /*
         * Make sure that we found a NAME and didn't run out of arguments
         */
        if (!GET_CURRENT_ARG_TYPE(walk_state->arg_types)) {
                return_ACPI_STATUS(AE_AML_NO_OPERAND);
        }

        /* We know that this arg is a name, move to next arg */

        INCREMENT_ARG_LIST(walk_state->arg_types);

        /*
         * Find the object. This will either insert the object into
         * the namespace or simply look it up
         */
        walk_state->op = NULL;

        status = walk_state->descending_callback(walk_state, op);
        if (ACPI_FAILURE(status)) {
                ACPI_EXCEPTION((AE_INFO, status, "During name lookup/catalog"));
                return_ACPI_STATUS(status);
        }

        if (!*op) {
                return_ACPI_STATUS(AE_CTRL_PARSE_CONTINUE);
        }

        status = acpi_ps_next_parse_state(walk_state, *op, status);
        if (ACPI_FAILURE(status)) {
                if (status == AE_CTRL_PENDING) {
                        return_ACPI_STATUS(AE_CTRL_PARSE_PENDING);
                }
                return_ACPI_STATUS(status);
        }

        acpi_ps_append_arg(*op, unnamed_op->common.value.arg);
        acpi_gbl_depth++;

        if ((*op)->common.aml_opcode == AML_REGION_OP ||
            (*op)->common.aml_opcode == AML_DATA_REGION_OP) {
                /*
                 * Defer final parsing of an operation_region body, because we don't
                 * have enough info in the first pass to parse it correctly (i.e.,
                 * there may be method calls within the term_arg elements of the body.)
                 *
                 * However, we must continue parsing because the opregion is not a
                 * standalone package -- we don't know where the end is at this point.
                 *
                 * (Length is unknown until parse of the body complete)
                 */
                (*op)->named.data = aml_op_start;
                (*op)->named.length = 0;
        }

        return_ACPI_STATUS(AE_OK);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ps_create_op
 *
 * PARAMETERS:  walk_state          - Current state
 *              aml_op_start        - Op start in AML
 *              new_op              - Returned Op
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Get Op from AML
 *
 ******************************************************************************/

static acpi_status
acpi_ps_create_op(struct acpi_walk_state *walk_state,
                  u8 * aml_op_start, union acpi_parse_object **new_op)
{
        acpi_status status = AE_OK;
        union acpi_parse_object *op;
        union acpi_parse_object *named_op = NULL;
        union acpi_parse_object *parent_scope;
        u8 argument_count;
        const struct acpi_opcode_info *op_info;

        ACPI_FUNCTION_TRACE_PTR(ps_create_op, walk_state);

        status = acpi_ps_get_aml_opcode(walk_state);
        if (status == AE_CTRL_PARSE_CONTINUE) {
                return_ACPI_STATUS(AE_CTRL_PARSE_CONTINUE);
        }

        /* Create Op structure and append to parent's argument list */

        walk_state->op_info = acpi_ps_get_opcode_info(walk_state->opcode);
        op = acpi_ps_alloc_op(walk_state->opcode);
        if (!op) {
                return_ACPI_STATUS(AE_NO_MEMORY);
        }

        if (walk_state->op_info->flags & AML_NAMED) {
                status =
                    acpi_ps_build_named_op(walk_state, aml_op_start, op,
                                           &named_op);
                acpi_ps_free_op(op);
                if (ACPI_FAILURE(status)) {
                        return_ACPI_STATUS(status);
                }

                *new_op = named_op;
                return_ACPI_STATUS(AE_OK);
        }

        /* Not a named opcode, just allocate Op and append to parent */

        if (walk_state->op_info->flags & AML_CREATE) {
                /*
                 * Backup to beginning of create_xXXfield declaration
                 * body_length is unknown until we parse the body
                 */
                op->named.data = aml_op_start;
                op->named.length = 0;
        }

        if (walk_state->opcode == AML_BANK_FIELD_OP) {
                /*
                 * Backup to beginning of bank_field declaration
                 * body_length is unknown until we parse the body
                 */
                op->named.data = aml_op_start;
                op->named.length = 0;
        }

        parent_scope = acpi_ps_get_parent_scope(&(walk_state->parser_state));
        acpi_ps_append_arg(parent_scope, op);

        if (parent_scope) {
                op_info =
                    acpi_ps_get_opcode_info(parent_scope->common.aml_opcode);
                if (op_info->flags & AML_HAS_TARGET) {
                        argument_count =
                            acpi_ps_get_argument_count(op_info->type);
                        if (parent_scope->common.arg_list_length >
                            argument_count) {
                                op->common.flags |= ACPI_PARSEOP_TARGET;
                        }
                } else if (parent_scope->common.aml_opcode == AML_INCREMENT_OP) {
                        op->common.flags |= ACPI_PARSEOP_TARGET;
                }
        }

        if (walk_state->descending_callback != NULL) {
                /*
                 * Find the object. This will either insert the object into
                 * the namespace or simply look it up
                 */
                walk_state->op = *new_op = op;

                status = walk_state->descending_callback(walk_state, &op);
                status = acpi_ps_next_parse_state(walk_state, op, status);
                if (status == AE_CTRL_PENDING) {
                        status = AE_CTRL_PARSE_PENDING;
                }
        }

        return_ACPI_STATUS(status);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ps_get_arguments
 *
 * PARAMETERS:  walk_state          - Current state
 *              aml_op_start        - Op start in AML
 *              Op                  - Current Op
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Get arguments for passed Op.
 *
 ******************************************************************************/

static acpi_status
acpi_ps_get_arguments(struct acpi_walk_state *walk_state,
                      u8 * aml_op_start, union acpi_parse_object *op)
{
        acpi_status status = AE_OK;
        union acpi_parse_object *arg = NULL;
        const struct acpi_opcode_info *op_info;

        ACPI_FUNCTION_TRACE_PTR(ps_get_arguments, walk_state);

        switch (op->common.aml_opcode) {
        case AML_BYTE_OP:       /* AML_BYTEDATA_ARG */
        case AML_WORD_OP:       /* AML_WORDDATA_ARG */
        case AML_DWORD_OP:      /* AML_DWORDATA_ARG */
        case AML_QWORD_OP:      /* AML_QWORDATA_ARG */
        case AML_STRING_OP:     /* AML_ASCIICHARLIST_ARG */

                /* Fill in constant or string argument directly */

                acpi_ps_get_next_simple_arg(&(walk_state->parser_state),
                                            GET_CURRENT_ARG_TYPE(walk_state->
                                                                 arg_types),
                                            op);
                break;

        case AML_INT_NAMEPATH_OP:       /* AML_NAMESTRING_ARG */

                status =
                    acpi_ps_get_next_namepath(walk_state,
                                              &(walk_state->parser_state), op,
                                              1);
                if (ACPI_FAILURE(status)) {
                        return_ACPI_STATUS(status);
                }

                walk_state->arg_types = 0;
                break;

        default:
                /*
                 * Op is not a constant or string, append each argument to the Op
                 */
                while (GET_CURRENT_ARG_TYPE(walk_state->arg_types)
                       && !walk_state->arg_count) {
                        walk_state->aml_offset =
                            (u32) ACPI_PTR_DIFF(walk_state->parser_state.aml,
                                                walk_state->parser_state.
                                                aml_start);

                        status =
                            acpi_ps_get_next_arg(walk_state,
                                                 &(walk_state->parser_state),
                                                 GET_CURRENT_ARG_TYPE
                                                 (walk_state->arg_types), &arg);
                        if (ACPI_FAILURE(status)) {
                                return_ACPI_STATUS(status);
                        }

                        if (arg) {
                                arg->common.aml_offset = walk_state->aml_offset;
                                acpi_ps_append_arg(op, arg);
                        }

                        INCREMENT_ARG_LIST(walk_state->arg_types);
                }

                /*
                 * Handle executable code at "module-level". This refers to
                 * executable opcodes that appear outside of any control method.
                 */
                if ((walk_state->pass_number <= ACPI_IMODE_LOAD_PASS2) &&
                    ((walk_state->parse_flags & ACPI_PARSE_DISASSEMBLE) == 0)) {
                        /*
                         * We want to skip If/Else/While constructs during Pass1 because we
                         * want to actually conditionally execute the code during Pass2.
                         *
                         * Except for disassembly, where we always want to walk the
                         * If/Else/While packages
                         */
                        switch (op->common.aml_opcode) {
                        case AML_IF_OP:
                        case AML_ELSE_OP:
                        case AML_WHILE_OP:

                                /*
                                 * Currently supported module-level opcodes are:
                                 * IF/ELSE/WHILE. These appear to be the most common,
                                 * and easiest to support since they open an AML
                                 * package.
                                 */
                                if (walk_state->pass_number ==
                                    ACPI_IMODE_LOAD_PASS1) {
                                        acpi_ps_link_module_code(aml_op_start,
                                                                 walk_state->
                                                                 parser_state.
                                                                 pkg_end -
                                                                 aml_op_start,
                                                                 walk_state->
                                                                 owner_id);
                                }

                                ACPI_DEBUG_PRINT((ACPI_DB_PARSE,
                                                  "Pass1: Skipping an If/Else/While body\n"));

                                /* Skip body of if/else/while in pass 1 */

                                walk_state->parser_state.aml =
                                    walk_state->parser_state.pkg_end;
                                walk_state->arg_count = 0;
                                break;

                        default:
                                /*
                                 * Check for an unsupported executable opcode at module
                                 * level. We must be in PASS1, the parent must be a SCOPE,
                                 * The opcode class must be EXECUTE, and the opcode must
                                 * not be an argument to another opcode.
                                 */
                                if ((walk_state->pass_number ==
                                     ACPI_IMODE_LOAD_PASS1)
                                    && (op->common.parent->common.aml_opcode ==
                                        AML_SCOPE_OP)) {
                                        op_info =
                                            acpi_ps_get_opcode_info(op->common.
                                                                    aml_opcode);
                                        if ((op_info->class ==
                                             AML_CLASS_EXECUTE) && (!arg)) {
                                                ACPI_WARNING((AE_INFO,
                                                              "Detected an unsupported executable opcode "
                                                              "at module-level: [0x%.4X] at table offset 0x%.4X",
                                                              op->common.aml_opcode,
                                                              (u32)((aml_op_start - walk_state->parser_state.aml_start)
                                                                + sizeof(struct acpi_table_header))));
                                        }
                                }
                                break;
                        }
                }

                /* Special processing for certain opcodes */

                switch (op->common.aml_opcode) {
                case AML_METHOD_OP:
                        /*
                         * Skip parsing of control method because we don't have enough
                         * info in the first pass to parse it correctly.
                         *
                         * Save the length and address of the body
                         */
                        op->named.data = walk_state->parser_state.aml;
                        op->named.length = (u32)
                            (walk_state->parser_state.pkg_end -
                             walk_state->parser_state.aml);

                        /* Skip body of method */

                        walk_state->parser_state.aml =
                            walk_state->parser_state.pkg_end;
                        walk_state->arg_count = 0;
                        break;

                case AML_BUFFER_OP:
                case AML_PACKAGE_OP:
                case AML_VAR_PACKAGE_OP:

                        if ((op->common.parent) &&
                            (op->common.parent->common.aml_opcode ==
                             AML_NAME_OP)
                            && (walk_state->pass_number <=
                                ACPI_IMODE_LOAD_PASS2)) {
                                /*
                                 * Skip parsing of Buffers and Packages because we don't have
                                 * enough info in the first pass to parse them correctly.
                                 */
                                op->named.data = aml_op_start;
                                op->named.length = (u32)
                                    (walk_state->parser_state.pkg_end -
                                     aml_op_start);

                                /* Skip body */

                                walk_state->parser_state.aml =
                                    walk_state->parser_state.pkg_end;
                                walk_state->arg_count = 0;
                        }
                        break;

                case AML_WHILE_OP:

                        if (walk_state->control_state) {
                                walk_state->control_state->control.package_end =
                                    walk_state->parser_state.pkg_end;
                        }
                        break;

                default:

                        /* No action for all other opcodes */
                        break;
                }

                break;
        }

        return_ACPI_STATUS(AE_OK);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ps_link_module_code
 *
 * PARAMETERS:  aml_start           - Pointer to the AML
 *              aml_length          - Length of executable AML
 *              owner_id            - owner_id of module level code
 *
 * RETURN:      None.
 *
 * DESCRIPTION: Wrap the module-level code with a method object and link the
 *              object to the global list. Note, the mutex field of the method
 *              object is used to link multiple module-level code objects.
 *
 ******************************************************************************/

static void
acpi_ps_link_module_code(u8 *aml_start, u32 aml_length, acpi_owner_id owner_id)
{
        union acpi_operand_object *prev;
        union acpi_operand_object *next;
        union acpi_operand_object *method_obj;

        /* Get the tail of the list */

        prev = next = acpi_gbl_module_code_list;
        while (next) {
                prev = next;
                next = next->method.mutex;
        }

        /*
         * Insert the module level code into the list. Merge it if it is
         * adjacent to the previous element.
         */
        if (!prev ||
            ((prev->method.aml_start + prev->method.aml_length) != aml_start)) {

                /* Create, initialize, and link a new temporary method object */

                method_obj = acpi_ut_create_internal_object(ACPI_TYPE_METHOD);
                if (!method_obj) {
                        return;
                }

                method_obj->method.aml_start = aml_start;
                method_obj->method.aml_length = aml_length;
                method_obj->method.owner_id = owner_id;
                method_obj->method.flags |= AOPOBJ_MODULE_LEVEL;

                if (!prev) {
                        acpi_gbl_module_code_list = method_obj;
                } else {
                        prev->method.mutex = method_obj;
                }
        } else {
                prev->method.aml_length += aml_length;
        }
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ps_complete_op
 *
 * PARAMETERS:  walk_state          - Current state
 *              Op                  - Returned Op
 *              Status              - Parse status before complete Op
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Complete Op
 *
 ******************************************************************************/

static acpi_status
acpi_ps_complete_op(struct acpi_walk_state *walk_state,
                    union acpi_parse_object **op, acpi_status status)
{
        acpi_status status2;

        ACPI_FUNCTION_TRACE_PTR(ps_complete_op, walk_state);

        /*
         * Finished one argument of the containing scope
         */
        walk_state->parser_state.scope->parse_scope.arg_count--;

        /* Close this Op (will result in parse subtree deletion) */

        status2 = acpi_ps_complete_this_op(walk_state, *op);
        if (ACPI_FAILURE(status2)) {
                return_ACPI_STATUS(status2);
        }

        *op = NULL;

        switch (status) {
        case AE_OK:
                break;

        case AE_CTRL_TRANSFER:

                /* We are about to transfer to a called method */

                walk_state->prev_op = NULL;
                walk_state->prev_arg_types = walk_state->arg_types;
                return_ACPI_STATUS(status);

        case AE_CTRL_END:

                acpi_ps_pop_scope(&(walk_state->parser_state), op,
                                  &walk_state->arg_types,
                                  &walk_state->arg_count);

                if (*op) {
                        walk_state->op = *op;
                        walk_state->op_info =
                            acpi_ps_get_opcode_info((*op)->common.aml_opcode);
                        walk_state->opcode = (*op)->common.aml_opcode;

                        status = walk_state->ascending_callback(walk_state);
                        status =
                            acpi_ps_next_parse_state(walk_state, *op, status);

                        status2 = acpi_ps_complete_this_op(walk_state, *op);
                        if (ACPI_FAILURE(status2)) {
                                return_ACPI_STATUS(status2);
                        }
                }

                status = AE_OK;
                break;

        case AE_CTRL_BREAK:
        case AE_CTRL_CONTINUE:

                /* Pop off scopes until we find the While */

                while (!(*op) || ((*op)->common.aml_opcode != AML_WHILE_OP)) {
                        acpi_ps_pop_scope(&(walk_state->parser_state), op,
                                          &walk_state->arg_types,
                                          &walk_state->arg_count);
                }

                /* Close this iteration of the While loop */

                walk_state->op = *op;
                walk_state->op_info =
                    acpi_ps_get_opcode_info((*op)->common.aml_opcode);
                walk_state->opcode = (*op)->common.aml_opcode;

                status = walk_state->ascending_callback(walk_state);
                status = acpi_ps_next_parse_state(walk_state, *op, status);

                status2 = acpi_ps_complete_this_op(walk_state, *op);
                if (ACPI_FAILURE(status2)) {
                        return_ACPI_STATUS(status2);
                }

                status = AE_OK;
                break;

        case AE_CTRL_TERMINATE:

                /* Clean up */
                do {
                        if (*op) {
                                status2 =
                                    acpi_ps_complete_this_op(walk_state, *op);
                                if (ACPI_FAILURE(status2)) {
                                        return_ACPI_STATUS(status2);
                                }

                                acpi_ut_delete_generic_state
                                    (acpi_ut_pop_generic_state
                                     (&walk_state->control_state));
                        }

                        acpi_ps_pop_scope(&(walk_state->parser_state), op,
                                          &walk_state->arg_types,
                                          &walk_state->arg_count);

                } while (*op);

                return_ACPI_STATUS(AE_OK);

        default:                /* All other non-AE_OK status */

                do {
                        if (*op) {
                                status2 =
                                    acpi_ps_complete_this_op(walk_state, *op);
                                if (ACPI_FAILURE(status2)) {
                                        return_ACPI_STATUS(status2);
                                }
                        }

                        acpi_ps_pop_scope(&(walk_state->parser_state), op,
                                          &walk_state->arg_types,
                                          &walk_state->arg_count);

                } while (*op);

#if 0
                /*
                 * TBD: Cleanup parse ops on error
                 */
                if (*op == NULL) {
                        acpi_ps_pop_scope(parser_state, op,
                                          &walk_state->arg_types,
                                          &walk_state->arg_count);
                }
#endif
                walk_state->prev_op = NULL;
                walk_state->prev_arg_types = walk_state->arg_types;
                return_ACPI_STATUS(status);
        }

        /* This scope complete? */

        if (acpi_ps_has_completed_scope(&(walk_state->parser_state))) {
                acpi_ps_pop_scope(&(walk_state->parser_state), op,
                                  &walk_state->arg_types,
                                  &walk_state->arg_count);
                ACPI_DEBUG_PRINT((ACPI_DB_PARSE, "Popped scope, Op=%p\n", *op));
        } else {
                *op = NULL;
        }

        ACPI_PREEMPTION_POINT();

        return_ACPI_STATUS(AE_OK);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ps_complete_final_op
 *
 * PARAMETERS:  walk_state          - Current state
 *              Op                  - Current Op
 *              Status              - Current parse status before complete last
 *                                    Op
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Complete last Op.
 *
 ******************************************************************************/

static acpi_status
acpi_ps_complete_final_op(struct acpi_walk_state *walk_state,
                          union acpi_parse_object *op, acpi_status status)
{
        acpi_status status2;

        ACPI_FUNCTION_TRACE_PTR(ps_complete_final_op, walk_state);

        /*
         * Complete the last Op (if not completed), and clear the scope stack.
         * It is easily possible to end an AML "package" with an unbounded number
         * of open scopes (such as when several ASL blocks are closed with
         * sequential closing braces). We want to terminate each one cleanly.
         */
        ACPI_DEBUG_PRINT((ACPI_DB_PARSE, "AML package complete at Op %p\n",
                          op));
        do {
                if (op) {
                        if (walk_state->ascending_callback != NULL) {
                                walk_state->op = op;
                                walk_state->op_info =
                                    acpi_ps_get_opcode_info(op->common.
                                                            aml_opcode);
                                walk_state->opcode = op->common.aml_opcode;

                                status =
                                    walk_state->ascending_callback(walk_state);
                                status =
                                    acpi_ps_next_parse_state(walk_state, op,
                                                             status);
                                if (status == AE_CTRL_PENDING) {
                                        status =
                                            acpi_ps_complete_op(walk_state, &op,
                                                                AE_OK);
                                        if (ACPI_FAILURE(status)) {
                                                return_ACPI_STATUS(status);
                                        }
                                }

                                if (status == AE_CTRL_TERMINATE) {
                                        status = AE_OK;

                                        /* Clean up */
                                        do {
                                                if (op) {
                                                        status2 =
                                                            acpi_ps_complete_this_op
                                                            (walk_state, op);
                                                        if (ACPI_FAILURE
                                                            (status2)) {
                                                                return_ACPI_STATUS
                                                                    (status2);
                                                        }
                                                }

                                                acpi_ps_pop_scope(&
                                                                  (walk_state->
                                                                   parser_state),
                                                                  &op,
                                                                  &walk_state->
                                                                  arg_types,
                                                                  &walk_state->
                                                                  arg_count);

                                        } while (op);

                                        return_ACPI_STATUS(status);
                                }

                                else if (ACPI_FAILURE(status)) {

                                        /* First error is most important */

                                        (void)
                                            acpi_ps_complete_this_op(walk_state,
                                                                     op);
                                        return_ACPI_STATUS(status);
                                }
                        }

                        status2 = acpi_ps_complete_this_op(walk_state, op);
                        if (ACPI_FAILURE(status2)) {
                                return_ACPI_STATUS(status2);
                        }
                }

                acpi_ps_pop_scope(&(walk_state->parser_state), &op,
                                  &walk_state->arg_types,
                                  &walk_state->arg_count);

        } while (op);

        return_ACPI_STATUS(status);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ps_parse_loop
 *
 * PARAMETERS:  walk_state          - Current state
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Parse AML (pointed to by the current parser state) and return
 *              a tree of ops.
 *
 ******************************************************************************/

acpi_status acpi_ps_parse_loop(struct acpi_walk_state *walk_state)
{
        acpi_status status = AE_OK;
        union acpi_parse_object *op = NULL;     /* current op */
        struct acpi_parse_state *parser_state;
        u8 *aml_op_start = NULL;

        ACPI_FUNCTION_TRACE_PTR(ps_parse_loop, walk_state);

        if (walk_state->descending_callback == NULL) {
                return_ACPI_STATUS(AE_BAD_PARAMETER);
        }

        parser_state = &walk_state->parser_state;
        walk_state->arg_types = 0;

#if (!defined (ACPI_NO_METHOD_EXECUTION) && !defined (ACPI_CONSTANT_EVAL_ONLY))

        if (walk_state->walk_type & ACPI_WALK_METHOD_RESTART) {

                /* We are restarting a preempted control method */

                if (acpi_ps_has_completed_scope(parser_state)) {
                        /*
                         * We must check if a predicate to an IF or WHILE statement
                         * was just completed
                         */
                        if ((parser_state->scope->parse_scope.op) &&
                            ((parser_state->scope->parse_scope.op->common.
                              aml_opcode == AML_IF_OP)
                             || (parser_state->scope->parse_scope.op->common.
                                 aml_opcode == AML_WHILE_OP))
                            && (walk_state->control_state)
                            && (walk_state->control_state->common.state ==
                                ACPI_CONTROL_PREDICATE_EXECUTING)) {
                                /*
                                 * A predicate was just completed, get the value of the
                                 * predicate and branch based on that value
                                 */
                                walk_state->op = NULL;
                                status =
                                    acpi_ds_get_predicate_value(walk_state,
                                                                ACPI_TO_POINTER
                                                                (TRUE));
                                if (ACPI_FAILURE(status)
                                    && ((status & AE_CODE_MASK) !=
                                        AE_CODE_CONTROL)) {

                                        if (status == AE_AML_NO_RETURN_VALUE) {
                                                ACPI_EXCEPTION((AE_INFO, status,
                                                                "Invoked method did not return a value"));

                                        }

                                        ACPI_EXCEPTION((AE_INFO, status,
                                                        "GetPredicate Failed"));
                                        return_ACPI_STATUS(status);
                                }

                                status =
                                    acpi_ps_next_parse_state(walk_state, op,
                                                             status);
                        }

                        acpi_ps_pop_scope(parser_state, &op,
                                          &walk_state->arg_types,
                                          &walk_state->arg_count);
                        ACPI_DEBUG_PRINT((ACPI_DB_PARSE,
                                          "Popped scope, Op=%p\n", op));
                } else if (walk_state->prev_op) {

                        /* We were in the middle of an op */

                        op = walk_state->prev_op;
                        walk_state->arg_types = walk_state->prev_arg_types;
                }
        }
#endif

        /* Iterative parsing loop, while there is more AML to process: */

        while ((parser_state->aml < parser_state->aml_end) || (op)) {
                aml_op_start = parser_state->aml;
                if (!op) {
                        status =
                            acpi_ps_create_op(walk_state, aml_op_start, &op);
                        if (ACPI_FAILURE(status)) {
                                if (status == AE_CTRL_PARSE_CONTINUE) {
                                        continue;
                                }

                                if (status == AE_CTRL_PARSE_PENDING) {
                                        status = AE_OK;
                                }

                                status =
                                    acpi_ps_complete_op(walk_state, &op,
                                                        status);
                                if (ACPI_FAILURE(status)) {
                                        return_ACPI_STATUS(status);
                                }

                                continue;
                        }

                        op->common.aml_offset = walk_state->aml_offset;

                        if (walk_state->op_info) {
                                ACPI_DEBUG_PRINT((ACPI_DB_PARSE,
                                                  "Opcode %4.4X [%s] Op %p Aml %p AmlOffset %5.5X\n",
                                                  (u32) op->common.aml_opcode,
                                                  walk_state->op_info->name, op,
                                                  parser_state->aml,
                                                  op->common.aml_offset));
                        }
                }

                /*
                 * Start arg_count at zero because we don't know if there are
                 * any args yet
                 */
                walk_state->arg_count = 0;

                /* Are there any arguments that must be processed? */

                if (walk_state->arg_types) {

                        /* Get arguments */

                        status =
                            acpi_ps_get_arguments(walk_state, aml_op_start, op);
                        if (ACPI_FAILURE(status)) {
                                status =
                                    acpi_ps_complete_op(walk_state, &op,
                                                        status);
                                if (ACPI_FAILURE(status)) {
                                        return_ACPI_STATUS(status);
                                }

                                continue;
                        }
                }

                /* Check for arguments that need to be processed */

                if (walk_state->arg_count) {
                        /*
                         * There are arguments (complex ones), push Op and
                         * prepare for argument
                         */
                        status = acpi_ps_push_scope(parser_state, op,
                                                    walk_state->arg_types,
                                                    walk_state->arg_count);
                        if (ACPI_FAILURE(status)) {
                                status =
                                    acpi_ps_complete_op(walk_state, &op,
                                                        status);
                                if (ACPI_FAILURE(status)) {
                                        return_ACPI_STATUS(status);
                                }

                                continue;
                        }

                        op = NULL;
                        continue;
                }

                /*
                 * All arguments have been processed -- Op is complete,
                 * prepare for next
                 */
                walk_state->op_info =
                    acpi_ps_get_opcode_info(op->common.aml_opcode);
                if (walk_state->op_info->flags & AML_NAMED) {
                        if (acpi_gbl_depth) {
                                acpi_gbl_depth--;
                        }

                        if (op->common.aml_opcode == AML_REGION_OP ||
                            op->common.aml_opcode == AML_DATA_REGION_OP) {
                                /*
                                 * Skip parsing of control method or opregion body,
                                 * because we don't have enough info in the first pass
                                 * to parse them correctly.
                                 *
                                 * Completed parsing an op_region declaration, we now
                                 * know the length.
                                 */
                                op->named.length =
                                    (u32) (parser_state->aml - op->named.data);
                        }
                }

                if (walk_state->op_info->flags & AML_CREATE) {
                        /*
                         * Backup to beginning of create_xXXfield declaration (1 for
                         * Opcode)
                         *
                         * body_length is unknown until we parse the body
                         */
                        op->named.length =
                            (u32) (parser_state->aml - op->named.data);
                }

                if (op->common.aml_opcode == AML_BANK_FIELD_OP) {
                        /*
                         * Backup to beginning of bank_field declaration
                         *
                         * body_length is unknown until we parse the body
                         */
                        op->named.length =
                            (u32) (parser_state->aml - op->named.data);
                }

                /* This op complete, notify the dispatcher */

                if (walk_state->ascending_callback != NULL) {
                        walk_state->op = op;
                        walk_state->opcode = op->common.aml_opcode;

                        status = walk_state->ascending_callback(walk_state);
                        status =
                            acpi_ps_next_parse_state(walk_state, op, status);
                        if (status == AE_CTRL_PENDING) {
                                status = AE_OK;
                        }
                }

                status = acpi_ps_complete_op(walk_state, &op, status);
                if (ACPI_FAILURE(status)) {
                        return_ACPI_STATUS(status);
                }

        }                       /* while parser_state->Aml */

        status = acpi_ps_complete_final_op(walk_state, op, status);
        return_ACPI_STATUS(status);
}