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Linux kernel mirror (for testing)
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1/******************************************************************************
2 *
3 * Module Name: nswalk - Functions for walking the ACPI namespace
4 *
5 *****************************************************************************/
6
7/*
8 * Copyright (C) 2000 - 2008, Intel Corp.
9 * All rights reserved.
10 *
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.
25 *
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.
29 *
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.
42 */
43
44#include <acpi/acpi.h>
45#include <acpi/acnamesp.h>
46
47#define _COMPONENT ACPI_NAMESPACE
48ACPI_MODULE_NAME("nswalk")
49
50/*******************************************************************************
51 *
52 * FUNCTION: acpi_ns_get_next_node
53 *
54 * PARAMETERS: Type - Type of node to be searched for
55 * 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
59 *
60 * RETURN: struct acpi_namespace_node - Pointer to the NEXT child or NULL if
61 * none is found.
62 *
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.
66 *
67 ******************************************************************************/
68struct acpi_namespace_node *acpi_ns_get_next_node(acpi_object_type type, struct acpi_namespace_node
69 *parent_node, struct acpi_namespace_node
70 *child_node)
71{
72 struct acpi_namespace_node *next_node = NULL;
73
74 ACPI_FUNCTION_ENTRY();
75
76 if (!child_node) {
77
78 /* It's really the parent's _scope_ that we want */
79
80 next_node = parent_node->child;
81 }
82
83 else {
84 /* Start search at the NEXT node */
85
86 next_node = acpi_ns_get_next_valid_node(child_node);
87 }
88
89 /* If any type is OK, we are done */
90
91 if (type == ACPI_TYPE_ANY) {
92
93 /* next_node is NULL if we are at the end-of-list */
94
95 return (next_node);
96 }
97
98 /* Must search for the node -- but within this scope only */
99
100 while (next_node) {
101
102 /* If type matches, we are done */
103
104 if (next_node->type == type) {
105 return (next_node);
106 }
107
108 /* Otherwise, move on to the next node */
109
110 next_node = acpi_ns_get_next_valid_node(next_node);
111 }
112
113 /* Not found */
114
115 return (NULL);
116}
117
118/*******************************************************************************
119 *
120 * FUNCTION: acpi_ns_walk_namespace
121 *
122 * PARAMETERS: Type - acpi_object_type to search for
123 * start_node - Handle in namespace where search begins
124 * max_depth - Depth to which search is to reach
125 * Flags - Whether to unlock the NS before invoking
126 * the callback routine
127 * user_function - Called when an object of "Type" is found
128 * Context - Passed to user function
129 * return_value - from the user_function if terminated early.
130 * Otherwise, returns NULL.
131 * RETURNS: Status
132 *
133 * DESCRIPTION: Performs a modified depth-first walk of the namespace tree,
134 * starting (and ending) at the node specified by start_handle.
135 * The user_function is called whenever a node that matches
136 * the type parameter is found. If the user function returns
137 * a non-zero value, the search is terminated immediately and this
138 * value is returned to the caller.
139 *
140 * The point of this procedure is to provide a generic namespace
141 * walk routine that can be called from multiple places to
142 * provide multiple services; the User Function can be tailored
143 * to each task, whether it is a print function, a compare
144 * function, etc.
145 *
146 ******************************************************************************/
147
148acpi_status
149acpi_ns_walk_namespace(acpi_object_type type,
150 acpi_handle start_node,
151 u32 max_depth,
152 u32 flags,
153 acpi_walk_callback user_function,
154 void *context, void **return_value)
155{
156 acpi_status status;
157 acpi_status mutex_status;
158 struct acpi_namespace_node *child_node;
159 struct acpi_namespace_node *parent_node;
160 acpi_object_type child_type;
161 u32 level;
162
163 ACPI_FUNCTION_TRACE(ns_walk_namespace);
164
165 /* Special case for the namespace Root Node */
166
167 if (start_node == ACPI_ROOT_OBJECT) {
168 start_node = acpi_gbl_root_node;
169 }
170
171 /* Null child means "get first node" */
172
173 parent_node = start_node;
174 child_node = NULL;
175 child_type = ACPI_TYPE_ANY;
176 level = 1;
177
178 /*
179 * Traverse the tree of nodes until we bubble back up to where we
180 * started. When Level is zero, the loop is done because we have
181 * bubbled up to (and passed) the original parent handle (start_entry)
182 */
183 while (level > 0) {
184
185 /* Get the next node in this scope. Null if not found */
186
187 status = AE_OK;
188 child_node =
189 acpi_ns_get_next_node(ACPI_TYPE_ANY, parent_node,
190 child_node);
191 if (child_node) {
192
193 /* Found next child, get the type if we are not searching for ANY */
194
195 if (type != ACPI_TYPE_ANY) {
196 child_type = child_node->type;
197 }
198
199 /*
200 * Ignore all temporary namespace nodes (created during control
201 * method execution) unless told otherwise. These temporary nodes
202 * can cause a race condition because they can be deleted during the
203 * execution of the user function (if the namespace is unlocked before
204 * invocation of the user function.) Only the debugger namespace dump
205 * will examine the temporary nodes.
206 */
207 if ((child_node->flags & ANOBJ_TEMPORARY) &&
208 !(flags & ACPI_NS_WALK_TEMP_NODES)) {
209 status = AE_CTRL_DEPTH;
210 }
211
212 /* Type must match requested type */
213
214 else if (child_type == type) {
215 /*
216 * Found a matching node, invoke the user callback function.
217 * Unlock the namespace if flag is set.
218 */
219 if (flags & ACPI_NS_WALK_UNLOCK) {
220 mutex_status =
221 acpi_ut_release_mutex
222 (ACPI_MTX_NAMESPACE);
223 if (ACPI_FAILURE(mutex_status)) {
224 return_ACPI_STATUS
225 (mutex_status);
226 }
227 }
228
229 status =
230 user_function(child_node, level, context,
231 return_value);
232
233 if (flags & ACPI_NS_WALK_UNLOCK) {
234 mutex_status =
235 acpi_ut_acquire_mutex
236 (ACPI_MTX_NAMESPACE);
237 if (ACPI_FAILURE(mutex_status)) {
238 return_ACPI_STATUS
239 (mutex_status);
240 }
241 }
242
243 switch (status) {
244 case AE_OK:
245 case AE_CTRL_DEPTH:
246
247 /* Just keep going */
248 break;
249
250 case AE_CTRL_TERMINATE:
251
252 /* Exit now, with OK status */
253
254 return_ACPI_STATUS(AE_OK);
255
256 default:
257
258 /* All others are valid exceptions */
259
260 return_ACPI_STATUS(status);
261 }
262 }
263
264 /*
265 * Depth first search: Attempt to go down another level in the
266 * namespace if we are allowed to. Don't go any further if we have
267 * reached the caller specified maximum depth or if the user
268 * function has specified that the maximum depth has been reached.
269 */
270 if ((level < max_depth) && (status != AE_CTRL_DEPTH)) {
271 if (acpi_ns_get_next_node
272 (ACPI_TYPE_ANY, child_node, NULL)) {
273
274 /* There is at least one child of this node, visit it */
275
276 level++;
277 parent_node = child_node;
278 child_node = NULL;
279 }
280 }
281 } else {
282 /*
283 * No more children of this node (acpi_ns_get_next_node failed), go
284 * back upwards in the namespace tree to the node's parent.
285 */
286 level--;
287 child_node = parent_node;
288 parent_node = acpi_ns_get_parent_node(parent_node);
289 }
290 }
291
292 /* Complete walk, not terminated by user function */
293
294 return_ACPI_STATUS(AE_OK);
295}