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[pohmelfs.git] / drivers / acpi / acpica / nswalk.c
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1 /******************************************************************************
3 * Module Name: nswalk - Functions for walking the ACPI namespace
5 *****************************************************************************/
7 /*
8 * Copyright (C) 2000 - 2012, Intel Corp.
9 * All rights reserved.
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 * notice, this list of conditions, and the following disclaimer,
16 * without modification.
17 * 2. Redistributions in binary form must reproduce at minimum a disclaimer
18 * substantially similar to the "NO WARRANTY" disclaimer below
19 * ("Disclaimer") and any redistribution must be conditioned upon
20 * including a substantially similar Disclaimer requirement for further
21 * binary redistribution.
22 * 3. Neither the names of the above-listed copyright holders nor the names
23 * of any contributors may be used to endorse or promote products derived
24 * from this software without specific prior written permission.
26 * Alternatively, this software may be distributed under the terms of the
27 * GNU General Public License ("GPL") version 2 as published by the Free
28 * Software Foundation.
30 * NO WARRANTY
31 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
32 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
33 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
34 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
35 * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
36 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
37 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
38 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
39 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
40 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
41 * POSSIBILITY OF SUCH DAMAGES.
44 #include <acpi/acpi.h>
45 #include "accommon.h"
46 #include "acnamesp.h"
48 #define _COMPONENT ACPI_NAMESPACE
49 ACPI_MODULE_NAME("nswalk")
51 /*******************************************************************************
53 * FUNCTION: acpi_ns_get_next_node
55 * PARAMETERS: parent_node - Parent node whose children we are
56 * getting
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
61 * none is found.
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(struct acpi_namespace_node
69 *parent_node,
70 struct acpi_namespace_node
71 *child_node)
73 ACPI_FUNCTION_ENTRY();
75 if (!child_node) {
77 /* It's really the parent's _scope_ that we want */
79 return parent_node->child;
82 /* Otherwise just return the next peer */
84 return child_node->peer;
87 /*******************************************************************************
89 * FUNCTION: acpi_ns_get_next_node_typed
91 * PARAMETERS: Type - Type of node to be searched for
92 * parent_node - Parent node whose children we are
93 * getting
94 * child_node - Previous child that was found.
95 * The NEXT child will be returned
97 * RETURN: struct acpi_namespace_node - Pointer to the NEXT child or NULL if
98 * none is found.
100 * DESCRIPTION: Return the next peer node within the namespace. If Handle
101 * is valid, Scope is ignored. Otherwise, the first node
102 * within Scope is returned.
104 ******************************************************************************/
106 struct acpi_namespace_node *acpi_ns_get_next_node_typed(acpi_object_type type,
107 struct
108 acpi_namespace_node
109 *parent_node,
110 struct
111 acpi_namespace_node
112 *child_node)
114 struct acpi_namespace_node *next_node = NULL;
116 ACPI_FUNCTION_ENTRY();
118 next_node = acpi_ns_get_next_node(parent_node, child_node);
121 /* If any type is OK, we are done */
123 if (type == ACPI_TYPE_ANY) {
125 /* next_node is NULL if we are at the end-of-list */
127 return (next_node);
130 /* Must search for the node -- but within this scope only */
132 while (next_node) {
134 /* If type matches, we are done */
136 if (next_node->type == type) {
137 return (next_node);
140 /* Otherwise, move on to the next peer node */
142 next_node = next_node->peer;
145 /* Not found */
147 return (NULL);
150 /*******************************************************************************
152 * FUNCTION: acpi_ns_walk_namespace
154 * PARAMETERS: Type - acpi_object_type to search for
155 * start_node - Handle in namespace where search begins
156 * max_depth - Depth to which search is to reach
157 * Flags - Whether to unlock the NS before invoking
158 * the callback routine
159 * pre_order_visit - Called during tree pre-order visit
160 * when an object of "Type" is found
161 * post_order_visit - Called during tree post-order visit
162 * when an object of "Type" is found
163 * Context - Passed to user function(s) above
164 * return_value - from the user_function if terminated
165 * early. Otherwise, returns NULL.
166 * RETURNS: Status
168 * DESCRIPTION: Performs a modified depth-first walk of the namespace tree,
169 * starting (and ending) at the node specified by start_handle.
170 * The callback function is called whenever a node that matches
171 * the type parameter is found. If the callback function returns
172 * a non-zero value, the search is terminated immediately and
173 * this value is returned to the caller.
175 * The point of this procedure is to provide a generic namespace
176 * walk routine that can be called from multiple places to
177 * provide multiple services; the callback function(s) can be
178 * tailored to each task, whether it is a print function,
179 * a compare function, etc.
181 ******************************************************************************/
183 acpi_status
184 acpi_ns_walk_namespace(acpi_object_type type,
185 acpi_handle start_node,
186 u32 max_depth,
187 u32 flags,
188 acpi_walk_callback pre_order_visit,
189 acpi_walk_callback post_order_visit,
190 void *context, void **return_value)
192 acpi_status status;
193 acpi_status mutex_status;
194 struct acpi_namespace_node *child_node;
195 struct acpi_namespace_node *parent_node;
196 acpi_object_type child_type;
197 u32 level;
198 u8 node_previously_visited = FALSE;
200 ACPI_FUNCTION_TRACE(ns_walk_namespace);
202 /* Special case for the namespace Root Node */
204 if (start_node == ACPI_ROOT_OBJECT) {
205 start_node = acpi_gbl_root_node;
208 /* Null child means "get first node" */
210 parent_node = start_node;
211 child_node = acpi_ns_get_next_node(parent_node, NULL);
212 child_type = ACPI_TYPE_ANY;
213 level = 1;
216 * Traverse the tree of nodes until we bubble back up to where we
217 * started. When Level is zero, the loop is done because we have
218 * bubbled up to (and passed) the original parent handle (start_entry)
220 while (level > 0 && child_node) {
221 status = AE_OK;
223 /* Found next child, get the type if we are not searching for ANY */
225 if (type != ACPI_TYPE_ANY) {
226 child_type = child_node->type;
230 * Ignore all temporary namespace nodes (created during control
231 * method execution) unless told otherwise. These temporary nodes
232 * can cause a race condition because they can be deleted during
233 * the execution of the user function (if the namespace is
234 * unlocked before invocation of the user function.) Only the
235 * debugger namespace dump will examine the temporary nodes.
237 if ((child_node->flags & ANOBJ_TEMPORARY) &&
238 !(flags & ACPI_NS_WALK_TEMP_NODES)) {
239 status = AE_CTRL_DEPTH;
242 /* Type must match requested type */
244 else if (child_type == type) {
246 * Found a matching node, invoke the user callback function.
247 * Unlock the namespace if flag is set.
249 if (flags & ACPI_NS_WALK_UNLOCK) {
250 mutex_status =
251 acpi_ut_release_mutex(ACPI_MTX_NAMESPACE);
252 if (ACPI_FAILURE(mutex_status)) {
253 return_ACPI_STATUS(mutex_status);
258 * Invoke the user function, either pre-order or post-order
259 * or both.
261 if (!node_previously_visited) {
262 if (pre_order_visit) {
263 status =
264 pre_order_visit(child_node, level,
265 context,
266 return_value);
268 } else {
269 if (post_order_visit) {
270 status =
271 post_order_visit(child_node, level,
272 context,
273 return_value);
277 if (flags & ACPI_NS_WALK_UNLOCK) {
278 mutex_status =
279 acpi_ut_acquire_mutex(ACPI_MTX_NAMESPACE);
280 if (ACPI_FAILURE(mutex_status)) {
281 return_ACPI_STATUS(mutex_status);
285 switch (status) {
286 case AE_OK:
287 case AE_CTRL_DEPTH:
289 /* Just keep going */
290 break;
292 case AE_CTRL_TERMINATE:
294 /* Exit now, with OK status */
296 return_ACPI_STATUS(AE_OK);
298 default:
300 /* All others are valid exceptions */
302 return_ACPI_STATUS(status);
307 * Depth first search: Attempt to go down another level in the
308 * namespace if we are allowed to. Don't go any further if we have
309 * reached the caller specified maximum depth or if the user
310 * function has specified that the maximum depth has been reached.
312 if (!node_previously_visited &&
313 (level < max_depth) && (status != AE_CTRL_DEPTH)) {
314 if (child_node->child) {
316 /* There is at least one child of this node, visit it */
318 level++;
319 parent_node = child_node;
320 child_node =
321 acpi_ns_get_next_node(parent_node, NULL);
322 continue;
326 /* No more children, re-visit this node */
328 if (!node_previously_visited) {
329 node_previously_visited = TRUE;
330 continue;
333 /* No more children, visit peers */
335 child_node = acpi_ns_get_next_node(parent_node, child_node);
336 if (child_node) {
337 node_previously_visited = FALSE;
340 /* No peers, re-visit parent */
342 else {
344 * No more children of this node (acpi_ns_get_next_node failed), go
345 * back upwards in the namespace tree to the node's parent.
347 level--;
348 child_node = parent_node;
349 parent_node = parent_node->parent;
351 node_previously_visited = TRUE;
355 /* Complete walk, not terminated by user function */
357 return_ACPI_STATUS(AE_OK);