]> err.no Git - linux-2.6/blobdiff - drivers/acpi/dispatcher/dswstate.c
Merge branch 'for-2.6.26' of master.kernel.org:/pub/scm/linux/kernel/git/jwboyer...
[linux-2.6] / drivers / acpi / dispatcher / dswstate.c
index 16c8e38b51ef944de7a1c90c6ae96cf30d61cfee..1386ced332ecedcacdd0a7c3d61fdcf89f409b20 100644 (file)
@@ -5,7 +5,7 @@
  *****************************************************************************/
 
 /*
- * Copyright (C) 2000 - 2007, R. Byron Moore
+ * Copyright (C) 2000 - 2008, Intel Corp.
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
 #define _COMPONENT          ACPI_DISPATCHER
 ACPI_MODULE_NAME("dswstate")
 
-/* Local prototypes */
-#ifdef ACPI_OBSOLETE_FUNCTIONS
-acpi_status
-acpi_ds_result_insert(void *object,
-                     u32 index, struct acpi_walk_state *walk_state);
-
-acpi_status acpi_ds_obj_stack_delete_all(struct acpi_walk_state *walk_state);
-
-acpi_status
-acpi_ds_obj_stack_pop_object(union acpi_operand_object **object,
-                            struct acpi_walk_state *walk_state);
-
-void *acpi_ds_obj_stack_get_value(u32 index,
-                                 struct acpi_walk_state *walk_state);
-#endif
-
-#ifdef ACPI_FUTURE_USAGE
-/*******************************************************************************
- *
- * FUNCTION:    acpi_ds_result_remove
- *
- * PARAMETERS:  Object              - Where to return the popped object
- *              Index               - Where to extract the object
- *              walk_state          - Current Walk state
- *
- * RETURN:      Status
- *
- * DESCRIPTION: Pop an object off the bottom of this walk's result stack.  In
- *              other words, this is a FIFO.
- *
- ******************************************************************************/
-
-acpi_status
-acpi_ds_result_remove(union acpi_operand_object **object,
-                     u32 index, struct acpi_walk_state *walk_state)
-{
-       union acpi_generic_state *state;
-
-       ACPI_FUNCTION_NAME(ds_result_remove);
-
-       state = walk_state->results;
-       if (!state) {
-               ACPI_ERROR((AE_INFO, "No result object pushed! State=%p",
-                           walk_state));
-               return (AE_NOT_EXIST);
-       }
-
-       if (index >= ACPI_OBJ_MAX_OPERAND) {
-               ACPI_ERROR((AE_INFO,
-                           "Index out of range: %X State=%p Num=%X",
-                           index, walk_state, state->results.num_results));
-       }
-
-       /* Check for a valid result object */
-
-       if (!state->results.obj_desc[index]) {
-               ACPI_ERROR((AE_INFO,
-                           "Null operand! State=%p #Ops=%X, Index=%X",
-                           walk_state, state->results.num_results, index));
-               return (AE_AML_NO_RETURN_VALUE);
-       }
-
-       /* Remove the object */
-
-       state->results.num_results--;
-
-       *object = state->results.obj_desc[index];
-       state->results.obj_desc[index] = NULL;
-
-       ACPI_DEBUG_PRINT((ACPI_DB_EXEC,
-                         "Obj=%p [%s] Index=%X State=%p Num=%X\n",
-                         *object,
-                         (*object) ? acpi_ut_get_object_type_name(*object) :
-                         "NULL", index, walk_state,
-                         state->results.num_results));
-
-       return (AE_OK);
-}
-#endif                         /*  ACPI_FUTURE_USAGE  */
+  /* Local prototypes */
+static acpi_status acpi_ds_result_stack_push(struct acpi_walk_state *ws);
+static acpi_status acpi_ds_result_stack_pop(struct acpi_walk_state *ws);
 
 /*******************************************************************************
  *
@@ -138,122 +62,67 @@ acpi_ds_result_remove(union acpi_operand_object **object,
  *
  * RETURN:      Status
  *
- * DESCRIPTION: Pop an object off the bottom of this walk's result stack.  In
- *              other words, this is a FIFO.
+ * DESCRIPTION: Pop an object off the top of this walk's result stack
  *
  ******************************************************************************/
 
 acpi_status
-acpi_ds_result_pop(union acpi_operand_object ** object,
-                  struct acpi_walk_state * walk_state)
+acpi_ds_result_pop(union acpi_operand_object **object,
+                  struct acpi_walk_state *walk_state)
 {
        acpi_native_uint index;
        union acpi_generic_state *state;
+       acpi_status status;
 
        ACPI_FUNCTION_NAME(ds_result_pop);
 
        state = walk_state->results;
-       if (!state) {
-               return (AE_OK);
-       }
-
-       if (!state->results.num_results) {
-               ACPI_ERROR((AE_INFO, "Result stack is empty! State=%p",
-                           walk_state));
-               return (AE_AML_NO_RETURN_VALUE);
-       }
 
-       /* Remove top element */
+       /* Incorrect state of result stack */
 
-       state->results.num_results--;
-
-       for (index = ACPI_OBJ_NUM_OPERANDS; index; index--) {
-
-               /* Check for a valid result object */
-
-               if (state->results.obj_desc[index - 1]) {
-                       *object = state->results.obj_desc[index - 1];
-                       state->results.obj_desc[index - 1] = NULL;
-
-                       ACPI_DEBUG_PRINT((ACPI_DB_EXEC,
-                                         "Obj=%p [%s] Index=%X State=%p Num=%X\n",
-                                         *object,
-                                         (*object) ?
-                                         acpi_ut_get_object_type_name(*object)
-                                         : "NULL", (u32) index - 1, walk_state,
-                                         state->results.num_results));
-
-                       return (AE_OK);
-               }
+       if (state && !walk_state->result_count) {
+               ACPI_ERROR((AE_INFO, "No results on result stack"));
+               return (AE_AML_INTERNAL);
        }
 
-       ACPI_ERROR((AE_INFO, "No result objects! State=%p", walk_state));
-       return (AE_AML_NO_RETURN_VALUE);
-}
-
-/*******************************************************************************
- *
- * FUNCTION:    acpi_ds_result_pop_from_bottom
- *
- * PARAMETERS:  Object              - Where to return the popped object
- *              walk_state          - Current Walk state
- *
- * RETURN:      Status
- *
- * DESCRIPTION: Pop an object off the bottom of this walk's result stack.  In
- *              other words, this is a FIFO.
- *
- ******************************************************************************/
-
-acpi_status
-acpi_ds_result_pop_from_bottom(union acpi_operand_object ** object,
-                              struct acpi_walk_state * walk_state)
-{
-       acpi_native_uint index;
-       union acpi_generic_state *state;
+       if (!state && walk_state->result_count) {
+               ACPI_ERROR((AE_INFO, "No result state for result stack"));
+               return (AE_AML_INTERNAL);
+       }
 
-       ACPI_FUNCTION_NAME(ds_result_pop_from_bottom);
+       /* Empty result stack */
 
-       state = walk_state->results;
        if (!state) {
-               ACPI_ERROR((AE_INFO,
-                           "No result object pushed! State=%p", walk_state));
-               return (AE_NOT_EXIST);
-       }
-
-       if (!state->results.num_results) {
-               ACPI_ERROR((AE_INFO, "No result objects! State=%p",
+               ACPI_ERROR((AE_INFO, "Result stack is empty! State=%p",
                            walk_state));
                return (AE_AML_NO_RETURN_VALUE);
        }
 
-       /* Remove Bottom element */
-
-       *object = state->results.obj_desc[0];
-
-       /* Push entire stack down one element */
-
-       for (index = 0; index < state->results.num_results; index++) {
-               state->results.obj_desc[index] =
-                   state->results.obj_desc[index + 1];
-       }
+       /* Return object of the top element and clean that top element result stack */
 
-       state->results.num_results--;
-
-       /* Check for a valid result object */
+       walk_state->result_count--;
+       index = walk_state->result_count % ACPI_RESULTS_FRAME_OBJ_NUM;
 
+       *object = state->results.obj_desc[index];
        if (!*object) {
                ACPI_ERROR((AE_INFO,
-                           "Null operand! State=%p #Ops=%X Index=%X",
-                           walk_state, state->results.num_results,
-                           (u32) index));
+                           "No result objects on result stack, State=%p",
+                           walk_state));
                return (AE_AML_NO_RETURN_VALUE);
        }
 
-       ACPI_DEBUG_PRINT((ACPI_DB_EXEC, "Obj=%p [%s] Results=%p State=%p\n",
-                         *object,
-                         (*object) ? acpi_ut_get_object_type_name(*object) :
-                         "NULL", state, walk_state));
+       state->results.obj_desc[index] = NULL;
+       if (index == 0) {
+               status = acpi_ds_result_stack_pop(walk_state);
+               if (ACPI_FAILURE(status)) {
+                       return (status);
+               }
+       }
+
+       ACPI_DEBUG_PRINT((ACPI_DB_EXEC,
+                         "Obj=%p [%s] Index=%X State=%p Num=%X\n", *object,
+                         acpi_ut_get_object_type_name(*object),
+                         (u32) index, walk_state, walk_state->result_count));
 
        return (AE_OK);
 }
@@ -276,39 +145,56 @@ acpi_ds_result_push(union acpi_operand_object * object,
                    struct acpi_walk_state * walk_state)
 {
        union acpi_generic_state *state;
+       acpi_status status;
+       acpi_native_uint index;
 
        ACPI_FUNCTION_NAME(ds_result_push);
 
+       if (walk_state->result_count > walk_state->result_size) {
+               ACPI_ERROR((AE_INFO, "Result stack is full"));
+               return (AE_AML_INTERNAL);
+       } else if (walk_state->result_count == walk_state->result_size) {
+
+               /* Extend the result stack */
+
+               status = acpi_ds_result_stack_push(walk_state);
+               if (ACPI_FAILURE(status)) {
+                       ACPI_ERROR((AE_INFO,
+                                   "Failed to extend the result stack"));
+                       return (status);
+               }
+       }
+
+       if (!(walk_state->result_count < walk_state->result_size)) {
+               ACPI_ERROR((AE_INFO, "No free elements in result stack"));
+               return (AE_AML_INTERNAL);
+       }
+
        state = walk_state->results;
        if (!state) {
                ACPI_ERROR((AE_INFO, "No result stack frame during push"));
                return (AE_AML_INTERNAL);
        }
 
-       if (state->results.num_results == ACPI_OBJ_NUM_OPERANDS) {
-               ACPI_ERROR((AE_INFO,
-                           "Result stack overflow: Obj=%p State=%p Num=%X",
-                           object, walk_state, state->results.num_results));
-               return (AE_STACK_OVERFLOW);
-       }
-
        if (!object) {
                ACPI_ERROR((AE_INFO,
                            "Null Object! Obj=%p State=%p Num=%X",
-                           object, walk_state, state->results.num_results));
+                           object, walk_state, walk_state->result_count));
                return (AE_BAD_PARAMETER);
        }
 
-       state->results.obj_desc[state->results.num_results] = object;
-       state->results.num_results++;
+       /* Assign the address of object to the top free element of result stack */
+
+       index = walk_state->result_count % ACPI_RESULTS_FRAME_OBJ_NUM;
+       state->results.obj_desc[index] = object;
+       walk_state->result_count++;
 
        ACPI_DEBUG_PRINT((ACPI_DB_EXEC, "Obj=%p [%s] State=%p Num=%X Cur=%X\n",
                          object,
-                         object ?
                          acpi_ut_get_object_type_name((union
                                                        acpi_operand_object *)
-                                                      object) : "NULL",
-                         walk_state, state->results.num_results,
+                                                      object), walk_state,
+                         walk_state->result_count,
                          walk_state->current_result));
 
        return (AE_OK);
@@ -322,16 +208,25 @@ acpi_ds_result_push(union acpi_operand_object * object,
  *
  * RETURN:      Status
  *
- * DESCRIPTION: Push an object onto the walk_state result stack.
+ * DESCRIPTION: Push an object onto the walk_state result stack
  *
  ******************************************************************************/
 
-acpi_status acpi_ds_result_stack_push(struct acpi_walk_state * walk_state)
+static acpi_status acpi_ds_result_stack_push(struct acpi_walk_state *walk_state)
 {
        union acpi_generic_state *state;
 
        ACPI_FUNCTION_NAME(ds_result_stack_push);
 
+       /* Check for stack overflow */
+
+       if (((u32) walk_state->result_size + ACPI_RESULTS_FRAME_OBJ_NUM) >
+           ACPI_RESULTS_OBJ_NUM_MAX) {
+               ACPI_ERROR((AE_INFO, "Result stack overflow: State=%p Num=%X",
+                           walk_state, walk_state->result_size));
+               return (AE_STACK_OVERFLOW);
+       }
+
        state = acpi_ut_create_generic_state();
        if (!state) {
                return (AE_NO_MEMORY);
@@ -340,6 +235,10 @@ acpi_status acpi_ds_result_stack_push(struct acpi_walk_state * walk_state)
        state->common.descriptor_type = ACPI_DESC_TYPE_STATE_RESULT;
        acpi_ut_push_generic_state(&walk_state->results, state);
 
+       /* Increase the length of the result stack by the length of frame */
+
+       walk_state->result_size += ACPI_RESULTS_FRAME_OBJ_NUM;
+
        ACPI_DEBUG_PRINT((ACPI_DB_EXEC, "Results=%p State=%p\n",
                          state, walk_state));
 
@@ -354,11 +253,11 @@ acpi_status acpi_ds_result_stack_push(struct acpi_walk_state * walk_state)
  *
  * RETURN:      Status
  *
- * DESCRIPTION: Pop an object off of the walk_state result stack.
+ * DESCRIPTION: Pop an object off of the walk_state result stack
  *
  ******************************************************************************/
 
-acpi_status acpi_ds_result_stack_pop(struct acpi_walk_state * walk_state)
+static acpi_status acpi_ds_result_stack_pop(struct acpi_walk_state *walk_state)
 {
        union acpi_generic_state *state;
 
@@ -367,18 +266,27 @@ acpi_status acpi_ds_result_stack_pop(struct acpi_walk_state * walk_state)
        /* Check for stack underflow */
 
        if (walk_state->results == NULL) {
-               ACPI_DEBUG_PRINT((ACPI_DB_EXEC, "Underflow - State=%p\n",
+               ACPI_DEBUG_PRINT((ACPI_DB_EXEC,
+                                 "Result stack underflow - State=%p\n",
                                  walk_state));
                return (AE_AML_NO_OPERAND);
        }
 
+       if (walk_state->result_size < ACPI_RESULTS_FRAME_OBJ_NUM) {
+               ACPI_ERROR((AE_INFO, "Insufficient result stack size"));
+               return (AE_AML_INTERNAL);
+       }
+
        state = acpi_ut_pop_generic_state(&walk_state->results);
+       acpi_ut_delete_generic_state(state);
+
+       /* Decrease the length of result stack by the length of frame */
+
+       walk_state->result_size -= ACPI_RESULTS_FRAME_OBJ_NUM;
 
        ACPI_DEBUG_PRINT((ACPI_DB_EXEC,
                          "Result=%p RemainingResults=%X State=%p\n",
-                         state, state->results.num_results, walk_state));
-
-       acpi_ut_delete_generic_state(state);
+                         state, walk_state->result_count, walk_state));
 
        return (AE_OK);
 }
@@ -412,9 +320,13 @@ acpi_ds_obj_stack_push(void *object, struct acpi_walk_state * walk_state)
 
        /* Put the object onto the stack */
 
-       walk_state->operands[walk_state->num_operands] = object;
+       walk_state->operands[walk_state->operand_index] = object;
        walk_state->num_operands++;
 
+       /* For the usual order of filling the operand stack */
+
+       walk_state->operand_index++;
+
        ACPI_DEBUG_PRINT((ACPI_DB_EXEC, "Obj=%p [%s] State=%p #Ops=%X\n",
                          object,
                          acpi_ut_get_object_type_name((union
@@ -484,43 +396,36 @@ acpi_ds_obj_stack_pop(u32 pop_count, struct acpi_walk_state * walk_state)
  *
  ******************************************************************************/
 
-acpi_status
+void
 acpi_ds_obj_stack_pop_and_delete(u32 pop_count,
-                                struct acpi_walk_state * walk_state)
+                                struct acpi_walk_state *walk_state)
 {
-       u32 i;
+       acpi_native_int i;
        union acpi_operand_object *obj_desc;
 
        ACPI_FUNCTION_NAME(ds_obj_stack_pop_and_delete);
 
-       for (i = 0; i < pop_count; i++) {
-
-               /* Check for stack underflow */
+       if (pop_count == 0) {
+               return;
+       }
 
+       for (i = (acpi_native_int) (pop_count - 1); i >= 0; i--) {
                if (walk_state->num_operands == 0) {
-                       ACPI_ERROR((AE_INFO,
-                                   "Object stack underflow! Count=%X State=%p #Ops=%X",
-                                   pop_count, walk_state,
-                                   walk_state->num_operands));
-                       return (AE_STACK_UNDERFLOW);
+                       return;
                }
 
                /* Pop the stack and delete an object if present in this stack entry */
 
                walk_state->num_operands--;
-               obj_desc = walk_state->operands[walk_state->num_operands];
+               obj_desc = walk_state->operands[i];
                if (obj_desc) {
-                       acpi_ut_remove_reference(walk_state->
-                                                operands[walk_state->
-                                                         num_operands]);
-                       walk_state->operands[walk_state->num_operands] = NULL;
+                       acpi_ut_remove_reference(walk_state->operands[i]);
+                       walk_state->operands[i] = NULL;
                }
        }
 
        ACPI_DEBUG_PRINT((ACPI_DB_EXEC, "Count=%X State=%p #Ops=%X\n",
                          pop_count, walk_state, walk_state->num_operands));
-
-       return (AE_OK);
 }
 
 /*******************************************************************************
@@ -560,7 +465,7 @@ struct acpi_walk_state *acpi_ds_get_current_walk_state(struct acpi_thread_state
  *
  * RETURN:      None
  *
- * DESCRIPTION: Place the Thread state at the head of the state list.
+ * DESCRIPTION: Place the Thread state at the head of the state list
  *
  ******************************************************************************/
 
@@ -630,16 +535,12 @@ struct acpi_walk_state *acpi_ds_pop_walk_state(struct acpi_thread_state *thread)
  *
  ******************************************************************************/
 
-struct acpi_walk_state *acpi_ds_create_walk_state(acpi_owner_id owner_id,
-                                                 union acpi_parse_object
-                                                 *origin,
-                                                 union acpi_operand_object
-                                                 *method_desc,
-                                                 struct acpi_thread_state
+struct acpi_walk_state *acpi_ds_create_walk_state(acpi_owner_id owner_id, union acpi_parse_object
+                                                 *origin, union acpi_operand_object
+                                                 *method_desc, struct acpi_thread_state
                                                  *thread)
 {
        struct acpi_walk_state *walk_state;
-       acpi_status status;
 
        ACPI_FUNCTION_TRACE(ds_create_walk_state);
 
@@ -662,14 +563,6 @@ struct acpi_walk_state *acpi_ds_create_walk_state(acpi_owner_id owner_id,
        acpi_ds_method_data_init(walk_state);
 #endif
 
-       /* Create an initial result stack entry */
-
-       status = acpi_ds_result_stack_push(walk_state);
-       if (ACPI_FAILURE(status)) {
-               ACPI_FREE(walk_state);
-               return_PTR(NULL);
-       }
-
        /* Put the new state at the head of the walk list */
 
        if (thread) {
@@ -863,190 +756,3 @@ void acpi_ds_delete_walk_state(struct acpi_walk_state *walk_state)
        ACPI_FREE(walk_state);
        return_VOID;
 }
-
-#ifdef ACPI_OBSOLETE_FUNCTIONS
-/*******************************************************************************
- *
- * FUNCTION:    acpi_ds_result_insert
- *
- * PARAMETERS:  Object              - Object to push
- *              Index               - Where to insert the object
- *              walk_state          - Current Walk state
- *
- * RETURN:      Status
- *
- * DESCRIPTION: Insert an object onto this walk's result stack
- *
- ******************************************************************************/
-
-acpi_status
-acpi_ds_result_insert(void *object,
-                     u32 index, struct acpi_walk_state *walk_state)
-{
-       union acpi_generic_state *state;
-
-       ACPI_FUNCTION_NAME(ds_result_insert);
-
-       state = walk_state->results;
-       if (!state) {
-               ACPI_ERROR((AE_INFO, "No result object pushed! State=%p",
-                           walk_state));
-               return (AE_NOT_EXIST);
-       }
-
-       if (index >= ACPI_OBJ_NUM_OPERANDS) {
-               ACPI_ERROR((AE_INFO,
-                           "Index out of range: %X Obj=%p State=%p Num=%X",
-                           index, object, walk_state,
-                           state->results.num_results));
-               return (AE_BAD_PARAMETER);
-       }
-
-       if (!object) {
-               ACPI_ERROR((AE_INFO,
-                           "Null Object! Index=%X Obj=%p State=%p Num=%X",
-                           index, object, walk_state,
-                           state->results.num_results));
-               return (AE_BAD_PARAMETER);
-       }
-
-       state->results.obj_desc[index] = object;
-       state->results.num_results++;
-
-       ACPI_DEBUG_PRINT((ACPI_DB_EXEC,
-                         "Obj=%p [%s] State=%p Num=%X Cur=%X\n",
-                         object,
-                         object ?
-                         acpi_ut_get_object_type_name((union
-                                                       acpi_operand_object *)
-                                                      object) : "NULL",
-                         walk_state, state->results.num_results,
-                         walk_state->current_result));
-
-       return (AE_OK);
-}
-
-/*******************************************************************************
- *
- * FUNCTION:    acpi_ds_obj_stack_delete_all
- *
- * PARAMETERS:  walk_state          - Current Walk state
- *
- * RETURN:      Status
- *
- * DESCRIPTION: Clear the object stack by deleting all objects that are on it.
- *              Should be used with great care, if at all!
- *
- ******************************************************************************/
-
-acpi_status acpi_ds_obj_stack_delete_all(struct acpi_walk_state * walk_state)
-{
-       u32 i;
-
-       ACPI_FUNCTION_TRACE_PTR(ds_obj_stack_delete_all, walk_state);
-
-       /* The stack size is configurable, but fixed */
-
-       for (i = 0; i < ACPI_OBJ_NUM_OPERANDS; i++) {
-               if (walk_state->operands[i]) {
-                       acpi_ut_remove_reference(walk_state->operands[i]);
-                       walk_state->operands[i] = NULL;
-               }
-       }
-
-       return_ACPI_STATUS(AE_OK);
-}
-
-/*******************************************************************************
- *
- * FUNCTION:    acpi_ds_obj_stack_pop_object
- *
- * PARAMETERS:  Object              - Where to return the popped object
- *              walk_state          - Current Walk state
- *
- * RETURN:      Status
- *
- * DESCRIPTION: Pop this walk's object stack.  Objects on the stack are NOT
- *              deleted by this routine.
- *
- ******************************************************************************/
-
-acpi_status
-acpi_ds_obj_stack_pop_object(union acpi_operand_object **object,
-                            struct acpi_walk_state *walk_state)
-{
-       ACPI_FUNCTION_NAME(ds_obj_stack_pop_object);
-
-       /* Check for stack underflow */
-
-       if (walk_state->num_operands == 0) {
-               ACPI_ERROR((AE_INFO,
-                           "Missing operand/stack empty! State=%p #Ops=%X",
-                           walk_state, walk_state->num_operands));
-               *object = NULL;
-               return (AE_AML_NO_OPERAND);
-       }
-
-       /* Pop the stack */
-
-       walk_state->num_operands--;
-
-       /* Check for a valid operand */
-
-       if (!walk_state->operands[walk_state->num_operands]) {
-               ACPI_ERROR((AE_INFO,
-                           "Null operand! State=%p #Ops=%X",
-                           walk_state, walk_state->num_operands));
-               *object = NULL;
-               return (AE_AML_NO_OPERAND);
-       }
-
-       /* Get operand and set stack entry to null */
-
-       *object = walk_state->operands[walk_state->num_operands];
-       walk_state->operands[walk_state->num_operands] = NULL;
-
-       ACPI_DEBUG_PRINT((ACPI_DB_EXEC, "Obj=%p [%s] State=%p #Ops=%X\n",
-                         *object, acpi_ut_get_object_type_name(*object),
-                         walk_state, walk_state->num_operands));
-
-       return (AE_OK);
-}
-
-/*******************************************************************************
- *
- * FUNCTION:    acpi_ds_obj_stack_get_value
- *
- * PARAMETERS:  Index               - Stack index whose value is desired.  Based
- *                                    on the top of the stack (index=0 == top)
- *              walk_state          - Current Walk state
- *
- * RETURN:      Pointer to the requested operand
- *
- * DESCRIPTION: Retrieve an object from this walk's operand stack.  Index must
- *              be within the range of the current stack pointer.
- *
- ******************************************************************************/
-
-void *acpi_ds_obj_stack_get_value(u32 index, struct acpi_walk_state *walk_state)
-{
-
-       ACPI_FUNCTION_TRACE_PTR(ds_obj_stack_get_value, walk_state);
-
-       /* Can't do it if the stack is empty */
-
-       if (walk_state->num_operands == 0) {
-               return_PTR(NULL);
-       }
-
-       /* or if the index is past the top of the stack */
-
-       if (index > (walk_state->num_operands - (u32) 1)) {
-               return_PTR(NULL);
-       }
-
-       return_PTR(walk_state->
-                  operands[(acpi_native_uint) (walk_state->num_operands - 1) -
-                           index]);
-}
-#endif