linux/drivers/acpi/acpica/dswstate.c
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   1/******************************************************************************
   2 *
   3 * Module Name: dswstate - Dispatcher parse tree walk management routines
   4 *
   5 *****************************************************************************/
   6
   7/*
   8 * Copyright (C) 2000 - 2012, Intel Corp.
   9 * All rights reserved.
  10 *
  11 * Redistribution and use in source and binary forms, with or without
  12 * modification, are permitted provided that the following conditions
  13 * are met:
  14 * 1. Redistributions of source code must retain the above copyright
  15 *    notice, this list of conditions, and the following disclaimer,
  16 *    without modification.
  17 * 2. Redistributions in binary form must reproduce at minimum a disclaimer
  18 *    substantially similar to the "NO WARRANTY" disclaimer below
  19 *    ("Disclaimer") and any redistribution must be conditioned upon
  20 *    including a substantially similar Disclaimer requirement for further
  21 *    binary redistribution.
  22 * 3. Neither the names of the above-listed copyright holders nor the names
  23 *    of any contributors may be used to endorse or promote products derived
  24 *    from this software without specific prior written permission.
  25 *
  26 * Alternatively, this software may be distributed under the terms of the
  27 * GNU General Public License ("GPL") version 2 as published by the Free
  28 * Software Foundation.
  29 *
  30 * NO WARRANTY
  31 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  32 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  33 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
  34 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  35 * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  36 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  37 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  38 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  39 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
  40 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  41 * POSSIBILITY OF SUCH DAMAGES.
  42 */
  43
  44#include <acpi/acpi.h>
  45#include "accommon.h"
  46#include "acparser.h"
  47#include "acdispat.h"
  48#include "acnamesp.h"
  49
  50#define _COMPONENT          ACPI_DISPATCHER
  51ACPI_MODULE_NAME("dswstate")
  52
  53  /* Local prototypes */
  54static acpi_status
  55acpi_ds_result_stack_push(struct acpi_walk_state *walk_state);
  56static acpi_status acpi_ds_result_stack_pop(struct acpi_walk_state *walk_state);
  57
  58/*******************************************************************************
  59 *
  60 * FUNCTION:    acpi_ds_result_pop
  61 *
  62 * PARAMETERS:  object              - Where to return the popped object
  63 *              walk_state          - Current Walk state
  64 *
  65 * RETURN:      Status
  66 *
  67 * DESCRIPTION: Pop an object off the top of this walk's result stack
  68 *
  69 ******************************************************************************/
  70
  71acpi_status
  72acpi_ds_result_pop(union acpi_operand_object **object,
  73                   struct acpi_walk_state *walk_state)
  74{
  75        u32 index;
  76        union acpi_generic_state *state;
  77        acpi_status status;
  78
  79        ACPI_FUNCTION_NAME(ds_result_pop);
  80
  81        state = walk_state->results;
  82
  83        /* Incorrect state of result stack */
  84
  85        if (state && !walk_state->result_count) {
  86                ACPI_ERROR((AE_INFO, "No results on result stack"));
  87                return (AE_AML_INTERNAL);
  88        }
  89
  90        if (!state && walk_state->result_count) {
  91                ACPI_ERROR((AE_INFO, "No result state for result stack"));
  92                return (AE_AML_INTERNAL);
  93        }
  94
  95        /* Empty result stack */
  96
  97        if (!state) {
  98                ACPI_ERROR((AE_INFO, "Result stack is empty! State=%p",
  99                            walk_state));
 100                return (AE_AML_NO_RETURN_VALUE);
 101        }
 102
 103        /* Return object of the top element and clean that top element result stack */
 104
 105        walk_state->result_count--;
 106        index = (u32)walk_state->result_count % ACPI_RESULTS_FRAME_OBJ_NUM;
 107
 108        *object = state->results.obj_desc[index];
 109        if (!*object) {
 110                ACPI_ERROR((AE_INFO,
 111                            "No result objects on result stack, State=%p",
 112                            walk_state));
 113                return (AE_AML_NO_RETURN_VALUE);
 114        }
 115
 116        state->results.obj_desc[index] = NULL;
 117        if (index == 0) {
 118                status = acpi_ds_result_stack_pop(walk_state);
 119                if (ACPI_FAILURE(status)) {
 120                        return (status);
 121                }
 122        }
 123
 124        ACPI_DEBUG_PRINT((ACPI_DB_EXEC,
 125                          "Obj=%p [%s] Index=%X State=%p Num=%X\n", *object,
 126                          acpi_ut_get_object_type_name(*object),
 127                          index, walk_state, walk_state->result_count));
 128
 129        return (AE_OK);
 130}
 131
 132/*******************************************************************************
 133 *
 134 * FUNCTION:    acpi_ds_result_push
 135 *
 136 * PARAMETERS:  object              - Where to return the popped object
 137 *              walk_state          - Current Walk state
 138 *
 139 * RETURN:      Status
 140 *
 141 * DESCRIPTION: Push an object onto the current result stack
 142 *
 143 ******************************************************************************/
 144
 145acpi_status
 146acpi_ds_result_push(union acpi_operand_object * object,
 147                    struct acpi_walk_state * walk_state)
 148{
 149        union acpi_generic_state *state;
 150        acpi_status status;
 151        u32 index;
 152
 153        ACPI_FUNCTION_NAME(ds_result_push);
 154
 155        if (walk_state->result_count > walk_state->result_size) {
 156                ACPI_ERROR((AE_INFO, "Result stack is full"));
 157                return (AE_AML_INTERNAL);
 158        } else if (walk_state->result_count == walk_state->result_size) {
 159
 160                /* Extend the result stack */
 161
 162                status = acpi_ds_result_stack_push(walk_state);
 163                if (ACPI_FAILURE(status)) {
 164                        ACPI_ERROR((AE_INFO,
 165                                    "Failed to extend the result stack"));
 166                        return (status);
 167                }
 168        }
 169
 170        if (!(walk_state->result_count < walk_state->result_size)) {
 171                ACPI_ERROR((AE_INFO, "No free elements in result stack"));
 172                return (AE_AML_INTERNAL);
 173        }
 174
 175        state = walk_state->results;
 176        if (!state) {
 177                ACPI_ERROR((AE_INFO, "No result stack frame during push"));
 178                return (AE_AML_INTERNAL);
 179        }
 180
 181        if (!object) {
 182                ACPI_ERROR((AE_INFO,
 183                            "Null Object! Obj=%p State=%p Num=%u",
 184                            object, walk_state, walk_state->result_count));
 185                return (AE_BAD_PARAMETER);
 186        }
 187
 188        /* Assign the address of object to the top free element of result stack */
 189
 190        index = (u32)walk_state->result_count % ACPI_RESULTS_FRAME_OBJ_NUM;
 191        state->results.obj_desc[index] = object;
 192        walk_state->result_count++;
 193
 194        ACPI_DEBUG_PRINT((ACPI_DB_EXEC, "Obj=%p [%s] State=%p Num=%X Cur=%X\n",
 195                          object,
 196                          acpi_ut_get_object_type_name((union
 197                                                        acpi_operand_object *)
 198                                                       object), walk_state,
 199                          walk_state->result_count,
 200                          walk_state->current_result));
 201
 202        return (AE_OK);
 203}
 204
 205/*******************************************************************************
 206 *
 207 * FUNCTION:    acpi_ds_result_stack_push
 208 *
 209 * PARAMETERS:  walk_state          - Current Walk state
 210 *
 211 * RETURN:      Status
 212 *
 213 * DESCRIPTION: Push an object onto the walk_state result stack
 214 *
 215 ******************************************************************************/
 216
 217static acpi_status acpi_ds_result_stack_push(struct acpi_walk_state *walk_state)
 218{
 219        union acpi_generic_state *state;
 220
 221        ACPI_FUNCTION_NAME(ds_result_stack_push);
 222
 223        /* Check for stack overflow */
 224
 225        if (((u32) walk_state->result_size + ACPI_RESULTS_FRAME_OBJ_NUM) >
 226            ACPI_RESULTS_OBJ_NUM_MAX) {
 227                ACPI_ERROR((AE_INFO, "Result stack overflow: State=%p Num=%u",
 228                            walk_state, walk_state->result_size));
 229                return (AE_STACK_OVERFLOW);
 230        }
 231
 232        state = acpi_ut_create_generic_state();
 233        if (!state) {
 234                return (AE_NO_MEMORY);
 235        }
 236
 237        state->common.descriptor_type = ACPI_DESC_TYPE_STATE_RESULT;
 238        acpi_ut_push_generic_state(&walk_state->results, state);
 239
 240        /* Increase the length of the result stack by the length of frame */
 241
 242        walk_state->result_size += ACPI_RESULTS_FRAME_OBJ_NUM;
 243
 244        ACPI_DEBUG_PRINT((ACPI_DB_EXEC, "Results=%p State=%p\n",
 245                          state, walk_state));
 246
 247        return (AE_OK);
 248}
 249
 250/*******************************************************************************
 251 *
 252 * FUNCTION:    acpi_ds_result_stack_pop
 253 *
 254 * PARAMETERS:  walk_state          - Current Walk state
 255 *
 256 * RETURN:      Status
 257 *
 258 * DESCRIPTION: Pop an object off of the walk_state result stack
 259 *
 260 ******************************************************************************/
 261
 262static acpi_status acpi_ds_result_stack_pop(struct acpi_walk_state *walk_state)
 263{
 264        union acpi_generic_state *state;
 265
 266        ACPI_FUNCTION_NAME(ds_result_stack_pop);
 267
 268        /* Check for stack underflow */
 269
 270        if (walk_state->results == NULL) {
 271                ACPI_DEBUG_PRINT((ACPI_DB_EXEC,
 272                                  "Result stack underflow - State=%p\n",
 273                                  walk_state));
 274                return (AE_AML_NO_OPERAND);
 275        }
 276
 277        if (walk_state->result_size < ACPI_RESULTS_FRAME_OBJ_NUM) {
 278                ACPI_ERROR((AE_INFO, "Insufficient result stack size"));
 279                return (AE_AML_INTERNAL);
 280        }
 281
 282        state = acpi_ut_pop_generic_state(&walk_state->results);
 283        acpi_ut_delete_generic_state(state);
 284
 285        /* Decrease the length of result stack by the length of frame */
 286
 287        walk_state->result_size -= ACPI_RESULTS_FRAME_OBJ_NUM;
 288
 289        ACPI_DEBUG_PRINT((ACPI_DB_EXEC,
 290                          "Result=%p RemainingResults=%X State=%p\n",
 291                          state, walk_state->result_count, walk_state));
 292
 293        return (AE_OK);
 294}
 295
 296/*******************************************************************************
 297 *
 298 * FUNCTION:    acpi_ds_obj_stack_push
 299 *
 300 * PARAMETERS:  object              - Object to push
 301 *              walk_state          - Current Walk state
 302 *
 303 * RETURN:      Status
 304 *
 305 * DESCRIPTION: Push an object onto this walk's object/operand stack
 306 *
 307 ******************************************************************************/
 308
 309acpi_status
 310acpi_ds_obj_stack_push(void *object, struct acpi_walk_state * walk_state)
 311{
 312        ACPI_FUNCTION_NAME(ds_obj_stack_push);
 313
 314        /* Check for stack overflow */
 315
 316        if (walk_state->num_operands >= ACPI_OBJ_NUM_OPERANDS) {
 317                ACPI_ERROR((AE_INFO,
 318                            "Object stack overflow! Obj=%p State=%p #Ops=%u",
 319                            object, walk_state, walk_state->num_operands));
 320                return (AE_STACK_OVERFLOW);
 321        }
 322
 323        /* Put the object onto the stack */
 324
 325        walk_state->operands[walk_state->operand_index] = object;
 326        walk_state->num_operands++;
 327
 328        /* For the usual order of filling the operand stack */
 329
 330        walk_state->operand_index++;
 331
 332        ACPI_DEBUG_PRINT((ACPI_DB_EXEC, "Obj=%p [%s] State=%p #Ops=%X\n",
 333                          object,
 334                          acpi_ut_get_object_type_name((union
 335                                                        acpi_operand_object *)
 336                                                       object), walk_state,
 337                          walk_state->num_operands));
 338
 339        return (AE_OK);
 340}
 341
 342/*******************************************************************************
 343 *
 344 * FUNCTION:    acpi_ds_obj_stack_pop
 345 *
 346 * PARAMETERS:  pop_count           - Number of objects/entries to pop
 347 *              walk_state          - Current Walk state
 348 *
 349 * RETURN:      Status
 350 *
 351 * DESCRIPTION: Pop this walk's object stack. Objects on the stack are NOT
 352 *              deleted by this routine.
 353 *
 354 ******************************************************************************/
 355
 356acpi_status
 357acpi_ds_obj_stack_pop(u32 pop_count, struct acpi_walk_state * walk_state)
 358{
 359        u32 i;
 360
 361        ACPI_FUNCTION_NAME(ds_obj_stack_pop);
 362
 363        for (i = 0; i < pop_count; i++) {
 364
 365                /* Check for stack underflow */
 366
 367                if (walk_state->num_operands == 0) {
 368                        ACPI_ERROR((AE_INFO,
 369                                    "Object stack underflow! Count=%X State=%p #Ops=%u",
 370                                    pop_count, walk_state,
 371                                    walk_state->num_operands));
 372                        return (AE_STACK_UNDERFLOW);
 373                }
 374
 375                /* Just set the stack entry to null */
 376
 377                walk_state->num_operands--;
 378                walk_state->operands[walk_state->num_operands] = NULL;
 379        }
 380
 381        ACPI_DEBUG_PRINT((ACPI_DB_EXEC, "Count=%X State=%p #Ops=%u\n",
 382                          pop_count, walk_state, walk_state->num_operands));
 383
 384        return (AE_OK);
 385}
 386
 387/*******************************************************************************
 388 *
 389 * FUNCTION:    acpi_ds_obj_stack_pop_and_delete
 390 *
 391 * PARAMETERS:  pop_count           - Number of objects/entries to pop
 392 *              walk_state          - Current Walk state
 393 *
 394 * RETURN:      Status
 395 *
 396 * DESCRIPTION: Pop this walk's object stack and delete each object that is
 397 *              popped off.
 398 *
 399 ******************************************************************************/
 400
 401void
 402acpi_ds_obj_stack_pop_and_delete(u32 pop_count,
 403                                 struct acpi_walk_state *walk_state)
 404{
 405        s32 i;
 406        union acpi_operand_object *obj_desc;
 407
 408        ACPI_FUNCTION_NAME(ds_obj_stack_pop_and_delete);
 409
 410        if (pop_count == 0) {
 411                return;
 412        }
 413
 414        for (i = (s32) pop_count - 1; i >= 0; i--) {
 415                if (walk_state->num_operands == 0) {
 416                        return;
 417                }
 418
 419                /* Pop the stack and delete an object if present in this stack entry */
 420
 421                walk_state->num_operands--;
 422                obj_desc = walk_state->operands[i];
 423                if (obj_desc) {
 424                        acpi_ut_remove_reference(walk_state->operands[i]);
 425                        walk_state->operands[i] = NULL;
 426                }
 427        }
 428
 429        ACPI_DEBUG_PRINT((ACPI_DB_EXEC, "Count=%X State=%p #Ops=%X\n",
 430                          pop_count, walk_state, walk_state->num_operands));
 431}
 432
 433/*******************************************************************************
 434 *
 435 * FUNCTION:    acpi_ds_get_current_walk_state
 436 *
 437 * PARAMETERS:  thread          - Get current active state for this Thread
 438 *
 439 * RETURN:      Pointer to the current walk state
 440 *
 441 * DESCRIPTION: Get the walk state that is at the head of the list (the "current"
 442 *              walk state.)
 443 *
 444 ******************************************************************************/
 445
 446struct acpi_walk_state *acpi_ds_get_current_walk_state(struct acpi_thread_state
 447                                                       *thread)
 448{
 449        ACPI_FUNCTION_NAME(ds_get_current_walk_state);
 450
 451        if (!thread) {
 452                return (NULL);
 453        }
 454
 455        ACPI_DEBUG_PRINT((ACPI_DB_PARSE, "Current WalkState %p\n",
 456                          thread->walk_state_list));
 457
 458        return (thread->walk_state_list);
 459}
 460
 461/*******************************************************************************
 462 *
 463 * FUNCTION:    acpi_ds_push_walk_state
 464 *
 465 * PARAMETERS:  walk_state      - State to push
 466 *              thread          - Thread state object
 467 *
 468 * RETURN:      None
 469 *
 470 * DESCRIPTION: Place the Thread state at the head of the state list
 471 *
 472 ******************************************************************************/
 473
 474void
 475acpi_ds_push_walk_state(struct acpi_walk_state *walk_state,
 476                        struct acpi_thread_state *thread)
 477{
 478        ACPI_FUNCTION_TRACE(ds_push_walk_state);
 479
 480        walk_state->next = thread->walk_state_list;
 481        thread->walk_state_list = walk_state;
 482
 483        return_VOID;
 484}
 485
 486/*******************************************************************************
 487 *
 488 * FUNCTION:    acpi_ds_pop_walk_state
 489 *
 490 * PARAMETERS:  thread      - Current thread state
 491 *
 492 * RETURN:      A walk_state object popped from the thread's stack
 493 *
 494 * DESCRIPTION: Remove and return the walkstate object that is at the head of
 495 *              the walk stack for the given walk list. NULL indicates that
 496 *              the list is empty.
 497 *
 498 ******************************************************************************/
 499
 500struct acpi_walk_state *acpi_ds_pop_walk_state(struct acpi_thread_state *thread)
 501{
 502        struct acpi_walk_state *walk_state;
 503
 504        ACPI_FUNCTION_TRACE(ds_pop_walk_state);
 505
 506        walk_state = thread->walk_state_list;
 507
 508        if (walk_state) {
 509
 510                /* Next walk state becomes the current walk state */
 511
 512                thread->walk_state_list = walk_state->next;
 513
 514                /*
 515                 * Don't clear the NEXT field, this serves as an indicator
 516                 * that there is a parent WALK STATE
 517                 * Do Not: walk_state->Next = NULL;
 518                 */
 519        }
 520
 521        return_PTR(walk_state);
 522}
 523
 524/*******************************************************************************
 525 *
 526 * FUNCTION:    acpi_ds_create_walk_state
 527 *
 528 * PARAMETERS:  owner_id        - ID for object creation
 529 *              origin          - Starting point for this walk
 530 *              method_desc     - Method object
 531 *              thread          - Current thread state
 532 *
 533 * RETURN:      Pointer to the new walk state.
 534 *
 535 * DESCRIPTION: Allocate and initialize a new walk state. The current walk
 536 *              state is set to this new state.
 537 *
 538 ******************************************************************************/
 539
 540struct acpi_walk_state *acpi_ds_create_walk_state(acpi_owner_id owner_id,
 541                                                  union acpi_parse_object
 542                                                  *origin,
 543                                                  union acpi_operand_object
 544                                                  *method_desc,
 545                                                  struct acpi_thread_state
 546                                                  *thread)
 547{
 548        struct acpi_walk_state *walk_state;
 549
 550        ACPI_FUNCTION_TRACE(ds_create_walk_state);
 551
 552        walk_state = ACPI_ALLOCATE_ZEROED(sizeof(struct acpi_walk_state));
 553        if (!walk_state) {
 554                return_PTR(NULL);
 555        }
 556
 557        walk_state->descriptor_type = ACPI_DESC_TYPE_WALK;
 558        walk_state->method_desc = method_desc;
 559        walk_state->owner_id = owner_id;
 560        walk_state->origin = origin;
 561        walk_state->thread = thread;
 562
 563        walk_state->parser_state.start_op = origin;
 564
 565        /* Init the method args/local */
 566
 567#if (!defined (ACPI_NO_METHOD_EXECUTION) && !defined (ACPI_CONSTANT_EVAL_ONLY))
 568        acpi_ds_method_data_init(walk_state);
 569#endif
 570
 571        /* Put the new state at the head of the walk list */
 572
 573        if (thread) {
 574                acpi_ds_push_walk_state(walk_state, thread);
 575        }
 576
 577        return_PTR(walk_state);
 578}
 579
 580/*******************************************************************************
 581 *
 582 * FUNCTION:    acpi_ds_init_aml_walk
 583 *
 584 * PARAMETERS:  walk_state      - New state to be initialized
 585 *              op              - Current parse op
 586 *              method_node     - Control method NS node, if any
 587 *              aml_start       - Start of AML
 588 *              aml_length      - Length of AML
 589 *              info            - Method info block (params, etc.)
 590 *              pass_number     - 1, 2, or 3
 591 *
 592 * RETURN:      Status
 593 *
 594 * DESCRIPTION: Initialize a walk state for a pass 1 or 2 parse tree walk
 595 *
 596 ******************************************************************************/
 597
 598acpi_status
 599acpi_ds_init_aml_walk(struct acpi_walk_state *walk_state,
 600                      union acpi_parse_object *op,
 601                      struct acpi_namespace_node *method_node,
 602                      u8 * aml_start,
 603                      u32 aml_length,
 604                      struct acpi_evaluate_info *info, u8 pass_number)
 605{
 606        acpi_status status;
 607        struct acpi_parse_state *parser_state = &walk_state->parser_state;
 608        union acpi_parse_object *extra_op;
 609
 610        ACPI_FUNCTION_TRACE(ds_init_aml_walk);
 611
 612        walk_state->parser_state.aml =
 613            walk_state->parser_state.aml_start = aml_start;
 614        walk_state->parser_state.aml_end =
 615            walk_state->parser_state.pkg_end = aml_start + aml_length;
 616
 617        /* The next_op of the next_walk will be the beginning of the method */
 618
 619        walk_state->next_op = NULL;
 620        walk_state->pass_number = pass_number;
 621
 622        if (info) {
 623                walk_state->params = info->parameters;
 624                walk_state->caller_return_desc = &info->return_object;
 625        }
 626
 627        status = acpi_ps_init_scope(&walk_state->parser_state, op);
 628        if (ACPI_FAILURE(status)) {
 629                return_ACPI_STATUS(status);
 630        }
 631
 632        if (method_node) {
 633                walk_state->parser_state.start_node = method_node;
 634                walk_state->walk_type = ACPI_WALK_METHOD;
 635                walk_state->method_node = method_node;
 636                walk_state->method_desc =
 637                    acpi_ns_get_attached_object(method_node);
 638
 639                /* Push start scope on scope stack and make it current  */
 640
 641                status =
 642                    acpi_ds_scope_stack_push(method_node, ACPI_TYPE_METHOD,
 643                                             walk_state);
 644                if (ACPI_FAILURE(status)) {
 645                        return_ACPI_STATUS(status);
 646                }
 647
 648                /* Init the method arguments */
 649
 650                status = acpi_ds_method_data_init_args(walk_state->params,
 651                                                       ACPI_METHOD_NUM_ARGS,
 652                                                       walk_state);
 653                if (ACPI_FAILURE(status)) {
 654                        return_ACPI_STATUS(status);
 655                }
 656        } else {
 657                /*
 658                 * Setup the current scope.
 659                 * Find a Named Op that has a namespace node associated with it.
 660                 * search upwards from this Op. Current scope is the first
 661                 * Op with a namespace node.
 662                 */
 663                extra_op = parser_state->start_op;
 664                while (extra_op && !extra_op->common.node) {
 665                        extra_op = extra_op->common.parent;
 666                }
 667
 668                if (!extra_op) {
 669                        parser_state->start_node = NULL;
 670                } else {
 671                        parser_state->start_node = extra_op->common.node;
 672                }
 673
 674                if (parser_state->start_node) {
 675
 676                        /* Push start scope on scope stack and make it current  */
 677
 678                        status =
 679                            acpi_ds_scope_stack_push(parser_state->start_node,
 680                                                     parser_state->start_node->
 681                                                     type, walk_state);
 682                        if (ACPI_FAILURE(status)) {
 683                                return_ACPI_STATUS(status);
 684                        }
 685                }
 686        }
 687
 688        status = acpi_ds_init_callbacks(walk_state, pass_number);
 689        return_ACPI_STATUS(status);
 690}
 691
 692/*******************************************************************************
 693 *
 694 * FUNCTION:    acpi_ds_delete_walk_state
 695 *
 696 * PARAMETERS:  walk_state      - State to delete
 697 *
 698 * RETURN:      Status
 699 *
 700 * DESCRIPTION: Delete a walk state including all internal data structures
 701 *
 702 ******************************************************************************/
 703
 704void acpi_ds_delete_walk_state(struct acpi_walk_state *walk_state)
 705{
 706        union acpi_generic_state *state;
 707
 708        ACPI_FUNCTION_TRACE_PTR(ds_delete_walk_state, walk_state);
 709
 710        if (!walk_state) {
 711                return_VOID;
 712        }
 713
 714        if (walk_state->descriptor_type != ACPI_DESC_TYPE_WALK) {
 715                ACPI_ERROR((AE_INFO, "%p is not a valid walk state",
 716                            walk_state));
 717                return_VOID;
 718        }
 719
 720        /* There should not be any open scopes */
 721
 722        if (walk_state->parser_state.scope) {
 723                ACPI_ERROR((AE_INFO, "%p walk still has a scope list",
 724                            walk_state));
 725                acpi_ps_cleanup_scope(&walk_state->parser_state);
 726        }
 727
 728        /* Always must free any linked control states */
 729
 730        while (walk_state->control_state) {
 731                state = walk_state->control_state;
 732                walk_state->control_state = state->common.next;
 733
 734                acpi_ut_delete_generic_state(state);
 735        }
 736
 737        /* Always must free any linked parse states */
 738
 739        while (walk_state->scope_info) {
 740                state = walk_state->scope_info;
 741                walk_state->scope_info = state->common.next;
 742
 743                acpi_ut_delete_generic_state(state);
 744        }
 745
 746        /* Always must free any stacked result states */
 747
 748        while (walk_state->results) {
 749                state = walk_state->results;
 750                walk_state->results = state->common.next;
 751
 752                acpi_ut_delete_generic_state(state);
 753        }
 754
 755        ACPI_FREE(walk_state);
 756        return_VOID;
 757}
 758