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Merge branch 'akpm'
[linux-2.6/next.git] / drivers / acpi / acpica / nssearch.c
blob28b0d7a62b9976c5cf04e1043f5293f81f8189f0
1 /*******************************************************************************
2 *
3 * Module Name: nssearch - Namespace search
4 *
5 ******************************************************************************/
6
7 /*
8 * Copyright (C) 2000 - 2011, 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 "accommon.h"
46 #include "acnamesp.h"
47
48 #ifdef ACPI_ASL_COMPILER
49 #include "amlcode.h"
50 #endif
51
52 #define _COMPONENT ACPI_NAMESPACE
53 ACPI_MODULE_NAME("nssearch")
54
55 /* Local prototypes */
56 static acpi_status
57 acpi_ns_search_parent_tree(u32 target_name,
58 struct acpi_namespace_node *node,
59 acpi_object_type type,
60 struct acpi_namespace_node **return_node);
61
62 /*******************************************************************************
63 *
64 * FUNCTION: acpi_ns_search_one_scope
65 *
66 * PARAMETERS: target_name - Ascii ACPI name to search for
67 * parent_node - Starting node where search will begin
68 * Type - Object type to match
69 * return_node - Where the matched Named obj is returned
70 *
71 * RETURN: Status
72 *
73 * DESCRIPTION: Search a single level of the namespace. Performs a
74 * simple search of the specified level, and does not add
75 * entries or search parents.
76 *
77 *
78 * Named object lists are built (and subsequently dumped) in the
79 * order in which the names are encountered during the namespace load;
80 *
81 * All namespace searching is linear in this implementation, but
82 * could be easily modified to support any improved search
83 * algorithm. However, the linear search was chosen for simplicity
84 * and because the trees are small and the other interpreter
85 * execution overhead is relatively high.
86 *
87 * Note: CPU execution analysis has shown that the AML interpreter spends
88 * a very small percentage of its time searching the namespace. Therefore,
89 * the linear search seems to be sufficient, as there would seem to be
90 * little value in improving the search.
91 *
92 ******************************************************************************/
93
94 acpi_status
95 acpi_ns_search_one_scope(u32 target_name,
96 struct acpi_namespace_node *parent_node,
97 acpi_object_type type,
98 struct acpi_namespace_node **return_node)
99 {
100 struct acpi_namespace_node *node;
101
102 ACPI_FUNCTION_TRACE(ns_search_one_scope);
103
104 #ifdef ACPI_DEBUG_OUTPUT
105 if (ACPI_LV_NAMES & acpi_dbg_level) {
106 char *scope_name;
107
108 scope_name = acpi_ns_get_external_pathname(parent_node);
109 if (scope_name) {
110 ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
111 "Searching %s (%p) For [%4.4s] (%s)\n",
112 scope_name, parent_node,
113 ACPI_CAST_PTR(char, &target_name),
114 acpi_ut_get_type_name(type)));
115
116 ACPI_FREE(scope_name);
117 }
118 }
119 #endif
120
121 /*
122 * Search for name at this namespace level, which is to say that we
123 * must search for the name among the children of this object
124 */
125 node = parent_node->child;
126 while (node) {
127
128 /* Check for match against the name */
129
130 if (node->name.integer == target_name) {
131
132 /* Resolve a control method alias if any */
133
134 if (acpi_ns_get_type(node) ==
135 ACPI_TYPE_LOCAL_METHOD_ALIAS) {
136 node =
137 ACPI_CAST_PTR(struct acpi_namespace_node,
138 node->object);
139 }
140
141 /* Found matching entry */
142
143 ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
144 "Name [%4.4s] (%s) %p found in scope [%4.4s] %p\n",
145 ACPI_CAST_PTR(char, &target_name),
146 acpi_ut_get_type_name(node->type),
147 node,
148 acpi_ut_get_node_name(parent_node),
149 parent_node));
150
151 *return_node = node;
152 return_ACPI_STATUS(AE_OK);
153 }
154
155 /* Didn't match name, move on to the next peer object */
156
157 node = node->peer;
158 }
159
160 /* Searched entire namespace level, not found */
161
162 ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
163 "Name [%4.4s] (%s) not found in search in scope [%4.4s] "
164 "%p first child %p\n",
165 ACPI_CAST_PTR(char, &target_name),
166 acpi_ut_get_type_name(type),
167 acpi_ut_get_node_name(parent_node), parent_node,
168 parent_node->child));
169
170 return_ACPI_STATUS(AE_NOT_FOUND);
171 }
172
173 /*******************************************************************************
174 *
175 * FUNCTION: acpi_ns_search_parent_tree
176 *
177 * PARAMETERS: target_name - Ascii ACPI name to search for
178 * Node - Starting node where search will begin
179 * Type - Object type to match
180 * return_node - Where the matched Node is returned
181 *
182 * RETURN: Status
183 *
184 * DESCRIPTION: Called when a name has not been found in the current namespace
185 * level. Before adding it or giving up, ACPI scope rules require
186 * searching enclosing scopes in cases identified by acpi_ns_local().
187 *
188 * "A name is located by finding the matching name in the current
189 * name space, and then in the parent name space. If the parent
190 * name space does not contain the name, the search continues
191 * recursively until either the name is found or the name space
192 * does not have a parent (the root of the name space). This
193 * indicates that the name is not found" (From ACPI Specification,
194 * section 5.3)
195 *
196 ******************************************************************************/
197
198 static acpi_status
199 acpi_ns_search_parent_tree(u32 target_name,
200 struct acpi_namespace_node *node,
201 acpi_object_type type,
202 struct acpi_namespace_node **return_node)
203 {
204 acpi_status status;
205 struct acpi_namespace_node *parent_node;
206
207 ACPI_FUNCTION_TRACE(ns_search_parent_tree);
208
209 parent_node = node->parent;
210
211 /*
212 * If there is no parent (i.e., we are at the root) or type is "local",
213 * we won't be searching the parent tree.
214 */
215 if (!parent_node) {
216 ACPI_DEBUG_PRINT((ACPI_DB_NAMES, "[%4.4s] has no parent\n",
217 ACPI_CAST_PTR(char, &target_name)));
218 return_ACPI_STATUS(AE_NOT_FOUND);
219 }
220
221 if (acpi_ns_local(type)) {
222 ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
223 "[%4.4s] type [%s] must be local to this scope (no parent search)\n",
224 ACPI_CAST_PTR(char, &target_name),
225 acpi_ut_get_type_name(type)));
226 return_ACPI_STATUS(AE_NOT_FOUND);
227 }
228
229 /* Search the parent tree */
230
231 ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
232 "Searching parent [%4.4s] for [%4.4s]\n",
233 acpi_ut_get_node_name(parent_node),
234 ACPI_CAST_PTR(char, &target_name)));
235
236 /* Search parents until target is found or we have backed up to the root */
237
238 while (parent_node) {
239 /*
240 * Search parent scope. Use TYPE_ANY because we don't care about the
241 * object type at this point, we only care about the existence of
242 * the actual name we are searching for. Typechecking comes later.
243 */
244 status =
245 acpi_ns_search_one_scope(target_name, parent_node,
246 ACPI_TYPE_ANY, return_node);
247 if (ACPI_SUCCESS(status)) {
248 return_ACPI_STATUS(status);
249 }
250
251 /* Not found here, go up another level (until we reach the root) */
252
253 parent_node = parent_node->parent;
254 }
255
256 /* Not found in parent tree */
257
258 return_ACPI_STATUS(AE_NOT_FOUND);
259 }
260
261 /*******************************************************************************
262 *
263 * FUNCTION: acpi_ns_search_and_enter
264 *
265 * PARAMETERS: target_name - Ascii ACPI name to search for (4 chars)
266 * walk_state - Current state of the walk
267 * Node - Starting node where search will begin
268 * interpreter_mode - Add names only in ACPI_MODE_LOAD_PASS_x.
269 * Otherwise,search only.
270 * Type - Object type to match
271 * Flags - Flags describing the search restrictions
272 * return_node - Where the Node is returned
273 *
274 * RETURN: Status
275 *
276 * DESCRIPTION: Search for a name segment in a single namespace level,
277 * optionally adding it if it is not found. If the passed
278 * Type is not Any and the type previously stored in the
279 * entry was Any (i.e. unknown), update the stored type.
280 *
281 * In ACPI_IMODE_EXECUTE, search only.
282 * In other modes, search and add if not found.
283 *
284 ******************************************************************************/
285
286 acpi_status
287 acpi_ns_search_and_enter(u32 target_name,
288 struct acpi_walk_state *walk_state,
289 struct acpi_namespace_node *node,
290 acpi_interpreter_mode interpreter_mode,
291 acpi_object_type type,
292 u32 flags, struct acpi_namespace_node **return_node)
293 {
294 acpi_status status;
295 struct acpi_namespace_node *new_node;
296
297 ACPI_FUNCTION_TRACE(ns_search_and_enter);
298
299 /* Parameter validation */
300
301 if (!node || !target_name || !return_node) {
302 ACPI_ERROR((AE_INFO,
303 "Null parameter: Node %p Name 0x%X ReturnNode %p",
304 node, target_name, return_node));
305 return_ACPI_STATUS(AE_BAD_PARAMETER);
306 }
307
308 /*
309 * Name must consist of valid ACPI characters. We will repair the name if
310 * necessary because we don't want to abort because of this, but we want
311 * all namespace names to be printable. A warning message is appropriate.
312 *
313 * This issue came up because there are in fact machines that exhibit
314 * this problem, and we want to be able to enable ACPI support for them,
315 * even though there are a few bad names.
316 */
317 if (!acpi_ut_valid_acpi_name(target_name)) {
318 target_name =
319 acpi_ut_repair_name(ACPI_CAST_PTR(char, &target_name));
320
321 /* Report warning only if in strict mode or debug mode */
322
323 if (!acpi_gbl_enable_interpreter_slack) {
324 ACPI_WARNING((AE_INFO,
325 "Found bad character(s) in name, repaired: [%4.4s]\n",
326 ACPI_CAST_PTR(char, &target_name)));
327 } else {
328 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
329 "Found bad character(s) in name, repaired: [%4.4s]\n",
330 ACPI_CAST_PTR(char, &target_name)));
331 }
332 }
333
334 /* Try to find the name in the namespace level specified by the caller */
335
336 *return_node = ACPI_ENTRY_NOT_FOUND;
337 status = acpi_ns_search_one_scope(target_name, node, type, return_node);
338 if (status != AE_NOT_FOUND) {
339 /*
340 * If we found it AND the request specifies that a find is an error,
341 * return the error
342 */
343 if ((status == AE_OK) && (flags & ACPI_NS_ERROR_IF_FOUND)) {
344 status = AE_ALREADY_EXISTS;
345 }
346
347 /* Either found it or there was an error: finished either way */
348
349 return_ACPI_STATUS(status);
350 }
351
352 /*
353 * The name was not found. If we are NOT performing the first pass
354 * (name entry) of loading the namespace, search the parent tree (all the
355 * way to the root if necessary.) We don't want to perform the parent
356 * search when the namespace is actually being loaded. We want to perform
357 * the search when namespace references are being resolved (load pass 2)
358 * and during the execution phase.
359 */
360 if ((interpreter_mode != ACPI_IMODE_LOAD_PASS1) &&
361 (flags & ACPI_NS_SEARCH_PARENT)) {
362 /*
363 * Not found at this level - search parent tree according to the
364 * ACPI specification
365 */
366 status =
367 acpi_ns_search_parent_tree(target_name, node, type,
368 return_node);
369 if (ACPI_SUCCESS(status)) {
370 return_ACPI_STATUS(status);
371 }
372 }
373
374 /* In execute mode, just search, never add names. Exit now */
375
376 if (interpreter_mode == ACPI_IMODE_EXECUTE) {
377 ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
378 "%4.4s Not found in %p [Not adding]\n",
379 ACPI_CAST_PTR(char, &target_name), node));
380
381 return_ACPI_STATUS(AE_NOT_FOUND);
382 }
383
384 /* Create the new named object */
385
386 new_node = acpi_ns_create_node(target_name);
387 if (!new_node) {
388 return_ACPI_STATUS(AE_NO_MEMORY);
389 }
390 #ifdef ACPI_ASL_COMPILER
391
392 /* Node is an object defined by an External() statement */
393
394 if (flags & ACPI_NS_EXTERNAL) {
395 new_node->flags |= ANOBJ_IS_EXTERNAL;
396 }
397 #endif
398
399 if (flags & ACPI_NS_TEMPORARY) {
400 new_node->flags |= ANOBJ_TEMPORARY;
401 }
402
403 /* Install the new object into the parent's list of children */
404
405 acpi_ns_install_node(walk_state, node, new_node, type);
406 *return_node = new_node;
407 return_ACPI_STATUS(AE_OK);
408 }
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