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 node, Get the type if we are not
200 if (type != ACPI_TYPE_ANY) {
201 child_type = child_node->type;
204 if ((child_type == type) &&
205 (!(child_node->flags & ANOBJ_TEMPORARY) ||
206 (child_node->flags & ANOBJ_TEMPORARY)
207 && (flags & ACPI_NS_WALK_TEMP_NODES))) {
209 * Found a matching node, invoke the user
212 if (flags & ACPI_NS_WALK_UNLOCK) {
214 acpi_ut_release_mutex
215 (ACPI_MTX_NAMESPACE);
216 if (ACPI_FAILURE(mutex_status)) {
222 status = user_function(child_node, level,
223 context, return_value);
225 if (flags & ACPI_NS_WALK_UNLOCK) {
227 acpi_ut_acquire_mutex
228 (ACPI_MTX_NAMESPACE);
229 if (ACPI_FAILURE(mutex_status)) {
239 /* Just keep going */
242 case AE_CTRL_TERMINATE:
244 /* Exit now, with OK status */
246 return_ACPI_STATUS(AE_OK);
250 /* All others are valid exceptions */
252 return_ACPI_STATUS(status);
257 * Depth first search:
258 * Attempt to go down another level in the namespace
259 * if we are allowed to. Don't go any further if we
260 * have reached the caller specified maximum depth
261 * or if the user function has specified that the
262 * maximum depth has been reached.
264 if ((level < max_depth) && (status != AE_CTRL_DEPTH)) {
265 if (acpi_ns_get_next_node
266 (ACPI_TYPE_ANY, child_node, NULL)) {
268 * There is at least one child of this
269 * node, visit the onde
272 parent_node = child_node;
278 * No more children of this node (acpi_ns_get_next_node
279 * failed), go back upwards in the namespace tree to
283 child_node = parent_node;
284 parent_node = acpi_ns_get_parent_node(parent_node);
288 /* Complete walk, not terminated by user function */
290 return_ACPI_STATUS(AE_OK);