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/******************************************************************************
*
* Module Name: nswalk - Functions for walking the APCI namespace
* $Revision: 19 $
*
*****************************************************************************/
/*
* Copyright (C) 2000, 2001 R. Byron Moore
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include "acpi.h"
#include "acinterp.h"
#include "acnamesp.h"
#define _COMPONENT NAMESPACE
MODULE_NAME ("nswalk")
/****************************************************************************
*
* FUNCTION: Acpi_get_next_object
*
* PARAMETERS: Type - Type of object to be searched for
* Parent - Parent object whose children we are
* getting
* Last_child - Previous child that was found.
* The NEXT child will be returned
*
* RETURN: ACPI_NAMESPACE_NODE - Pointer to the NEXT child or NULL if
* none is found.
*
* DESCRIPTION: Return the next peer object within the namespace. If Handle
* is valid, Scope is ignored. Otherwise, the first object
* within Scope is returned.
*
****************************************************************************/
ACPI_NAMESPACE_NODE *
acpi_ns_get_next_object (
OBJECT_TYPE_INTERNAL type,
ACPI_NAMESPACE_NODE *parent_node,
ACPI_NAMESPACE_NODE *child_node)
{
ACPI_NAMESPACE_NODE *next_node = NULL;
if (!child_node) {
/* It's really the parent's _scope_ that we want */
if (parent_node->child) {
next_node = parent_node->child;
}
}
else {
/* Start search at the NEXT object */
next_node = acpi_ns_get_next_valid_object (child_node);
}
/* If any type is OK, we are done */
if (type == ACPI_TYPE_ANY) {
/* Next_node is NULL if we are at the end-of-list */
return (next_node);
}
/* Must search for the object -- but within this scope only */
while (next_node) {
/* If type matches, we are done */
if (next_node->type == type) {
return (next_node);
}
/* Otherwise, move on to the next object */
next_node = acpi_ns_get_next_valid_object (next_node);
}
/* Not found */
return (NULL);
}
/******************************************************************************
*
* FUNCTION: Acpi_ns_walk_namespace
*
* PARAMETERS: Type - ACPI_OBJECT_TYPE to search for
* Start_node - Handle in namespace where search begins
* Max_depth - Depth to which search is to reach
* Unlock_before_callback- Whether to unlock the NS before invoking
* the callback routine
* User_function - Called when an object of "Type" is found
* Context - Passed to user function
*
* RETURNS Return value from the User_function if terminated early.
* Otherwise, returns NULL.
*
* DESCRIPTION: Performs a modified depth-first walk of the namespace tree,
* starting (and ending) at the object specified by Start_handle.
* The User_function is called whenever an object that matches
* the type parameter is found. If the user function returns
* a non-zero value, the search is terminated immediately and this
* value is returned to the caller.
*
* The point of this procedure is to provide a generic namespace
* walk routine that can be called from multiple places to
* provide multiple services; the User Function can be tailored
* to each task, whether it is a print function, a compare
* function, etc.
*
******************************************************************************/
ACPI_STATUS
acpi_ns_walk_namespace (
OBJECT_TYPE_INTERNAL type,
ACPI_HANDLE start_node,
u32 max_depth,
u8 unlock_before_callback,
WALK_CALLBACK user_function,
void *context,
void **return_value)
{
ACPI_STATUS status;
ACPI_NAMESPACE_NODE *child_node;
ACPI_NAMESPACE_NODE *parent_node;
OBJECT_TYPE_INTERNAL child_type;
u32 level;
/* Special case for the namespace Root Node */
if (start_node == ACPI_ROOT_OBJECT) {
start_node = acpi_gbl_root_node;
}
/* Null child means "get first object" */
parent_node = start_node;
child_node = 0;
child_type = ACPI_TYPE_ANY;
level = 1;
/*
* Traverse the tree of objects until we bubble back up to where we
* started. When Level is zero, the loop is done because we have
* bubbled up to (and passed) the original parent handle (Start_entry)
*/
while (level > 0) {
/*
* Get the next typed object in this scope. Null returned
* if not found
*/
status = AE_OK;
child_node = acpi_ns_get_next_object (ACPI_TYPE_ANY,
parent_node,
child_node);
if (child_node) {
/*
* Found an object, Get the type if we are not
* searching for ANY
*/
if (type != ACPI_TYPE_ANY) {
child_type = child_node->type;
}
if (child_type == type) {
/*
* Found a matching object, invoke the user
* callback function
*/
if (unlock_before_callback) {
acpi_cm_release_mutex (ACPI_MTX_NAMESPACE);
}
status = user_function (child_node, level,
context, return_value);
if (unlock_before_callback) {
acpi_cm_acquire_mutex (ACPI_MTX_NAMESPACE);
}
switch (status)
{
case AE_OK:
case AE_CTRL_DEPTH:
/* Just keep going */
break;
case AE_CTRL_TERMINATE:
/* Exit now, with OK status */
return (AE_OK);
break;
default:
/* All others are valid exceptions */
return (status);
break;
}
}
/*
* Depth first search:
* Attempt to go down another level in the namespace
* if we are allowed to. Don't go any further if we
* have reached the caller specified maximum depth
* or if the user function has specified that the
* maximum depth has been reached.
*/
if ((level < max_depth) && (status != AE_CTRL_DEPTH)) {
if (acpi_ns_get_next_object (ACPI_TYPE_ANY,
child_node, 0))
{
/*
* There is at least one child of this
* object, visit the object
*/
level++;
parent_node = child_node;
child_node = 0;
}
}
}
else {
/*
* No more children in this object (Acpi_ns_get_next_object
* failed), go back upwards in the namespace tree to
* the object's parent.
*/
level--;
child_node = parent_node;
parent_node = acpi_ns_get_parent_object (parent_node);
}
}
/* Complete walk, not terminated by user function */
return (AE_OK);
}
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