Viewing file:  nswalk.c (7.49 KB) -rw-r--r--
Select action/file-type:
 (+) |  (+) |  (+) | Code (+) | Session (+) |  (+) | SDB (+) |  (+) |  (+) |  (+) |  (+) |  (+) |
/******************************************************************************
*
* Module Name: nswalk - Functions for walking the ACPI namespace
* $Revision: 26 $
*
*****************************************************************************/
/*
* 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 ACPI_NAMESPACE
MODULE_NAME ("nswalk")
/*******************************************************************************
*
* FUNCTION: Acpi_ns_get_next_node
*
* PARAMETERS: Type - Type of node to be searched for
* Parent_node - Parent node whose children we are
* getting
* Child_node - 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 node within the namespace. If Handle
* is valid, Scope is ignored. Otherwise, the first node
* within Scope is returned.
*
******************************************************************************/
acpi_namespace_node *
acpi_ns_get_next_node (
acpi_object_type8 type,
acpi_namespace_node *parent_node,
acpi_namespace_node *child_node)
{
acpi_namespace_node *next_node = NULL;
FUNCTION_ENTRY ();
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 node */
next_node = acpi_ns_get_next_valid_node (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 node -- 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 node */
next_node = acpi_ns_get_next_valid_node (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
* Return_value - from the User_function if terminated early.
* Otherwise, returns NULL.
* RETURNS: Status
*
* DESCRIPTION: Performs a modified depth-first walk of the namespace tree,
* starting (and ending) at the node specified by Start_handle.
* The User_function is called whenever a node 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 (
acpi_object_type8 type,
acpi_handle start_node,
u32 max_depth,
u8 unlock_before_callback,
acpi_walk_callback user_function,
void *context,
void **return_value)
{
acpi_status status;
acpi_namespace_node *child_node;
acpi_namespace_node *parent_node;
acpi_object_type8 child_type;
u32 level;
FUNCTION_TRACE ("Ns_walk_namespace");
/* Special case for the namespace Root Node */
if (start_node == ACPI_ROOT_OBJECT) {
start_node = acpi_gbl_root_node;
}
/* Null child means "get first node" */
parent_node = start_node;
child_node = 0;
child_type = ACPI_TYPE_ANY;
level = 1;
/*
* Traverse the tree of nodes 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 node in this scope. Null if not found */
status = AE_OK;
child_node = acpi_ns_get_next_node (ACPI_TYPE_ANY, parent_node, child_node);
if (child_node) {
/*
* Found node, 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 node, invoke the user
* callback function
*/
if (unlock_before_callback) {
acpi_ut_release_mutex (ACPI_MTX_NAMESPACE);
}
status = user_function (child_node, level,
context, return_value);
if (unlock_before_callback) {
acpi_ut_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_ACPI_STATUS (AE_OK);
break;
default:
/* All others are valid exceptions */
return_ACPI_STATUS (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_node (ACPI_TYPE_ANY, child_node, 0)) {
/*
* There is at least one child of this
* node, visit the onde
*/
level++;
parent_node = child_node;
child_node = 0;
}
}
}
else {
/*
* No more children of this node (Acpi_ns_get_next_node
* failed), go back upwards in the namespace tree to
* the node's parent.
*/
level--;
child_node = parent_node;
parent_node = acpi_ns_get_parent_object (parent_node);
}
}
/* Complete walk, not terminated by user function */
return_ACPI_STATUS (AE_OK);
}
|