1 /******************************************************************************
3 * Module Name: nswalk - Functions for walking the ACPI namespace
5 *****************************************************************************/
8 * Copyright (C) 2000 - 2006, R. Byron Moore
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23 * of any contributors may be used to endorse or promote products derived
24 * from this software without specific prior written permission.
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44 #include <acpi/acpi.h>
45 #include <acpi/acnamesp.h>
47 #define _COMPONENT ACPI_NAMESPACE
48 ACPI_MODULE_NAME("nswalk")
50 /*******************************************************************************
52 * FUNCTION: acpi_ns_get_next_node
54 * PARAMETERS: Type - Type of node to be searched for
55 * parent_node - Parent node whose children we are
57 * child_node - Previous child that was found.
58 * The NEXT child will be returned
60 * RETURN: struct acpi_namespace_node - Pointer to the NEXT child or NULL if
63 * DESCRIPTION: Return the next peer node within the namespace. If Handle
64 * is valid, Scope is ignored. Otherwise, the first node
65 * within Scope is returned.
67 ******************************************************************************/
68 struct acpi_namespace_node *acpi_ns_get_next_node(acpi_object_type type,
69 struct acpi_namespace_node
71 struct acpi_namespace_node
74 struct acpi_namespace_node *next_node = NULL;
76 ACPI_FUNCTION_ENTRY();
80 /* It's really the parent's _scope_ that we want */
82 if (parent_node->child) {
83 next_node = parent_node->child;
88 /* Start search at the NEXT node */
90 next_node = acpi_ns_get_next_valid_node(child_node);
93 /* If any type is OK, we are done */
95 if (type == ACPI_TYPE_ANY) {
97 /* next_node is NULL if we are at the end-of-list */
102 /* Must search for the node -- but within this scope only */
106 /* If type matches, we are done */
108 if (next_node->type == type) {
112 /* Otherwise, move on to the next node */
114 next_node = acpi_ns_get_next_valid_node(next_node);
122 /*******************************************************************************
124 * FUNCTION: acpi_ns_walk_namespace
126 * PARAMETERS: Type - acpi_object_type to search for
127 * start_node - Handle in namespace where search begins
128 * max_depth - Depth to which search is to reach
129 * Flags - Whether to unlock the NS before invoking
130 * the callback routine
131 * user_function - Called when an object of "Type" is found
132 * Context - Passed to user function
133 * return_value - from the user_function if terminated early.
134 * Otherwise, returns NULL.
137 * DESCRIPTION: Performs a modified depth-first walk of the namespace tree,
138 * starting (and ending) at the node specified by start_handle.
139 * The user_function is called whenever a node that matches
140 * the type parameter is found. If the user function returns
141 * a non-zero value, the search is terminated immediately and this
142 * value is returned to the caller.
144 * The point of this procedure is to provide a generic namespace
145 * walk routine that can be called from multiple places to
146 * provide multiple services; the User Function can be tailored
147 * to each task, whether it is a print function, a compare
150 ******************************************************************************/
153 acpi_ns_walk_namespace(acpi_object_type type,
154 acpi_handle start_node,
157 acpi_walk_callback user_function,
158 void *context, void **return_value)
161 acpi_status mutex_status;
162 struct acpi_namespace_node *child_node;
163 struct acpi_namespace_node *parent_node;
164 acpi_object_type child_type;
167 ACPI_FUNCTION_TRACE(ns_walk_namespace);
169 /* Special case for the namespace Root Node */
171 if (start_node == ACPI_ROOT_OBJECT) {
172 start_node = acpi_gbl_root_node;
175 /* Null child means "get first node" */
177 parent_node = start_node;
179 child_type = ACPI_TYPE_ANY;
183 * Traverse the tree of nodes until we bubble back up to where we
184 * started. When Level is zero, the loop is done because we have
185 * bubbled up to (and passed) the original parent handle (start_entry)
189 /* Get the next node in this scope. Null if not found */
193 acpi_ns_get_next_node(ACPI_TYPE_ANY, parent_node,
197 /* Found next child, get the type if we are not searching for ANY */
199 if (type != ACPI_TYPE_ANY) {
200 child_type = child_node->type;
204 * Ignore all temporary namespace nodes (created during control
205 * method execution) unless told otherwise. These temporary nodes
206 * can cause a race condition because they can be deleted during the
207 * execution of the user function (if the namespace is unlocked before
208 * invocation of the user function.) Only the debugger namespace dump
209 * will examine the temporary nodes.
211 if ((child_node->flags & ANOBJ_TEMPORARY) &&
212 !(flags & ACPI_NS_WALK_TEMP_NODES)) {
213 status = AE_CTRL_DEPTH;
216 /* Type must match requested type */
218 else if (child_type == type) {
220 * Found a matching node, invoke the user callback function.
221 * Unlock the namespace if flag is set.
223 if (flags & ACPI_NS_WALK_UNLOCK) {
225 acpi_ut_release_mutex
226 (ACPI_MTX_NAMESPACE);
227 if (ACPI_FAILURE(mutex_status)) {
234 user_function(child_node, level, context,
237 if (flags & ACPI_NS_WALK_UNLOCK) {
239 acpi_ut_acquire_mutex
240 (ACPI_MTX_NAMESPACE);
241 if (ACPI_FAILURE(mutex_status)) {
251 /* Just keep going */
254 case AE_CTRL_TERMINATE:
256 /* Exit now, with OK status */
258 return_ACPI_STATUS(AE_OK);
262 /* All others are valid exceptions */
264 return_ACPI_STATUS(status);
269 * Depth first search: Attempt to go down another level in the
270 * namespace if we are allowed to. Don't go any further if we have
271 * reached the caller specified maximum depth or if the user
272 * function has specified that the maximum depth has been reached.
274 if ((level < max_depth) && (status != AE_CTRL_DEPTH)) {
275 if (acpi_ns_get_next_node
276 (ACPI_TYPE_ANY, child_node, NULL)) {
278 /* There is at least one child of this node, visit it */
281 parent_node = child_node;
287 * No more children of this node (acpi_ns_get_next_node failed), go
288 * back upwards in the namespace tree to the node's parent.
291 child_node = parent_node;
292 parent_node = acpi_ns_get_parent_node(parent_node);
296 /* Complete walk, not terminated by user function */
298 return_ACPI_STATUS(AE_OK);