Merge branch 'release' of master.kernel.org:/pub/scm/linux/kernel/git/lenb/linux...
[linux-2.6] / drivers / acpi / namespace / nssearch.c
1 /*******************************************************************************
2  *
3  * Module Name: nssearch - Namespace search
4  *
5  ******************************************************************************/
6
7 /*
8  * Copyright (C) 2000 - 2005, R. Byron Moore
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
48 ACPI_MODULE_NAME("nssearch")
49
50 /* Local prototypes */
51 static acpi_status
52 acpi_ns_search_parent_tree(u32 target_name,
53                            struct acpi_namespace_node *node,
54                            acpi_object_type type,
55                            struct acpi_namespace_node **return_node);
56
57 /*******************************************************************************
58  *
59  * FUNCTION:    acpi_ns_search_node
60  *
61  * PARAMETERS:  target_name     - Ascii ACPI name to search for
62  *              Node            - Starting node where search will begin
63  *              Type            - Object type to match
64  *              return_node     - Where the matched Named obj is returned
65  *
66  * RETURN:      Status
67  *
68  * DESCRIPTION: Search a single level of the namespace.  Performs a
69  *              simple search of the specified level, and does not add
70  *              entries or search parents.
71  *
72  *
73  *      Named object lists are built (and subsequently dumped) in the
74  *      order in which the names are encountered during the namespace load;
75  *
76  *      All namespace searching is linear in this implementation, but
77  *      could be easily modified to support any improved search
78  *      algorithm.  However, the linear search was chosen for simplicity
79  *      and because the trees are small and the other interpreter
80  *      execution overhead is relatively high.
81  *
82  ******************************************************************************/
83
84 acpi_status
85 acpi_ns_search_node(u32 target_name,
86                     struct acpi_namespace_node *node,
87                     acpi_object_type type,
88                     struct acpi_namespace_node **return_node)
89 {
90         struct acpi_namespace_node *next_node;
91
92         ACPI_FUNCTION_TRACE("ns_search_node");
93
94 #ifdef ACPI_DEBUG_OUTPUT
95         if (ACPI_LV_NAMES & acpi_dbg_level) {
96                 char *scope_name;
97
98                 scope_name = acpi_ns_get_external_pathname(node);
99                 if (scope_name) {
100                         ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
101                                           "Searching %s (%p) For [%4.4s] (%s)\n",
102                                           scope_name, node,
103                                           (char *)&target_name,
104                                           acpi_ut_get_type_name(type)));
105
106                         ACPI_MEM_FREE(scope_name);
107                 }
108         }
109 #endif
110
111         /*
112          * Search for name at this namespace level, which is to say that we
113          * must search for the name among the children of this object
114          */
115         next_node = node->child;
116         while (next_node) {
117                 /* Check for match against the name */
118
119                 if (next_node->name.integer == target_name) {
120                         /* Resolve a control method alias if any */
121
122                         if (acpi_ns_get_type(next_node) ==
123                             ACPI_TYPE_LOCAL_METHOD_ALIAS) {
124                                 next_node =
125                                     ACPI_CAST_PTR(struct acpi_namespace_node,
126                                                   next_node->object);
127                         }
128
129                         /*
130                          * Found matching entry.
131                          */
132                         ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
133                                           "Name [%4.4s] (%s) %p found in scope [%4.4s] %p\n",
134                                           (char *)&target_name,
135                                           acpi_ut_get_type_name(next_node->
136                                                                 type),
137                                           next_node,
138                                           acpi_ut_get_node_name(node), node));
139
140                         *return_node = next_node;
141                         return_ACPI_STATUS(AE_OK);
142                 }
143
144                 /*
145                  * The last entry in the list points back to the parent,
146                  * so a flag is used to indicate the end-of-list
147                  */
148                 if (next_node->flags & ANOBJ_END_OF_PEER_LIST) {
149                         /* Searched entire list, we are done */
150
151                         break;
152                 }
153
154                 /* Didn't match name, move on to the next peer object */
155
156                 next_node = next_node->peer;
157         }
158
159         /* Searched entire namespace level, not found */
160
161         ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
162                           "Name [%4.4s] (%s) not found in search in scope [%4.4s] %p first child %p\n",
163                           (char *)&target_name, acpi_ut_get_type_name(type),
164                           acpi_ut_get_node_name(node), node, node->child));
165
166         return_ACPI_STATUS(AE_NOT_FOUND);
167 }
168
169 /*******************************************************************************
170  *
171  * FUNCTION:    acpi_ns_search_parent_tree
172  *
173  * PARAMETERS:  target_name     - Ascii ACPI name to search for
174  *              Node            - Starting node where search will begin
175  *              Type            - Object type to match
176  *              return_node     - Where the matched Node is returned
177  *
178  * RETURN:      Status
179  *
180  * DESCRIPTION: Called when a name has not been found in the current namespace
181  *              level.  Before adding it or giving up, ACPI scope rules require
182  *              searching enclosing scopes in cases identified by acpi_ns_local().
183  *
184  *              "A name is located by finding the matching name in the current
185  *              name space, and then in the parent name space. If the parent
186  *              name space does not contain the name, the search continues
187  *              recursively until either the name is found or the name space
188  *              does not have a parent (the root of the name space).  This
189  *              indicates that the name is not found" (From ACPI Specification,
190  *              section 5.3)
191  *
192  ******************************************************************************/
193
194 static acpi_status
195 acpi_ns_search_parent_tree(u32 target_name,
196                            struct acpi_namespace_node *node,
197                            acpi_object_type type,
198                            struct acpi_namespace_node **return_node)
199 {
200         acpi_status status;
201         struct acpi_namespace_node *parent_node;
202
203         ACPI_FUNCTION_TRACE("ns_search_parent_tree");
204
205         parent_node = acpi_ns_get_parent_node(node);
206
207         /*
208          * If there is no parent (i.e., we are at the root) or type is "local",
209          * we won't be searching the parent tree.
210          */
211         if (!parent_node) {
212                 ACPI_DEBUG_PRINT((ACPI_DB_NAMES, "[%4.4s] has no parent\n",
213                                   (char *)&target_name));
214                 return_ACPI_STATUS(AE_NOT_FOUND);
215         }
216
217         if (acpi_ns_local(type)) {
218                 ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
219                                   "[%4.4s] type [%s] must be local to this scope (no parent search)\n",
220                                   (char *)&target_name,
221                                   acpi_ut_get_type_name(type)));
222                 return_ACPI_STATUS(AE_NOT_FOUND);
223         }
224
225         /* Search the parent tree */
226
227         ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
228                           "Searching parent [%4.4s] for [%4.4s]\n",
229                           acpi_ut_get_node_name(parent_node),
230                           (char *)&target_name));
231
232         /*
233          * Search parents until target is found or we have backed up to the root
234          */
235         while (parent_node) {
236                 /*
237                  * Search parent scope.  Use TYPE_ANY because we don't care about the
238                  * object type at this point, we only care about the existence of
239                  * the actual name we are searching for.  Typechecking comes later.
240                  */
241                 status = acpi_ns_search_node(target_name, parent_node,
242                                              ACPI_TYPE_ANY, return_node);
243                 if (ACPI_SUCCESS(status)) {
244                         return_ACPI_STATUS(status);
245                 }
246
247                 /*
248                  * Not found here, go up another level
249                  * (until we reach the root)
250                  */
251                 parent_node = acpi_ns_get_parent_node(parent_node);
252         }
253
254         /* Not found in parent tree */
255
256         return_ACPI_STATUS(AE_NOT_FOUND);
257 }
258
259 /*******************************************************************************
260  *
261  * FUNCTION:    acpi_ns_search_and_enter
262  *
263  * PARAMETERS:  target_name         - Ascii ACPI name to search for (4 chars)
264  *              walk_state          - Current state of the walk
265  *              Node                - Starting node where search will begin
266  *              interpreter_mode    - Add names only in ACPI_MODE_LOAD_PASS_x.
267  *                                    Otherwise,search only.
268  *              Type                - Object type to match
269  *              Flags               - Flags describing the search restrictions
270  *              return_node         - Where the Node is returned
271  *
272  * RETURN:      Status
273  *
274  * DESCRIPTION: Search for a name segment in a single namespace level,
275  *              optionally adding it if it is not found.  If the passed
276  *              Type is not Any and the type previously stored in the
277  *              entry was Any (i.e. unknown), update the stored type.
278  *
279  *              In ACPI_IMODE_EXECUTE, search only.
280  *              In other modes, search and add if not found.
281  *
282  ******************************************************************************/
283
284 acpi_status
285 acpi_ns_search_and_enter(u32 target_name,
286                          struct acpi_walk_state *walk_state,
287                          struct acpi_namespace_node *node,
288                          acpi_interpreter_mode interpreter_mode,
289                          acpi_object_type type,
290                          u32 flags, struct acpi_namespace_node **return_node)
291 {
292         acpi_status status;
293         struct acpi_namespace_node *new_node;
294
295         ACPI_FUNCTION_TRACE("ns_search_and_enter");
296
297         /* Parameter validation */
298
299         if (!node || !target_name || !return_node) {
300                 ACPI_DEBUG_PRINT((ACPI_DB_ERROR,
301                                   "Null param: Node %p Name %X return_node %p\n",
302                                   node, target_name, return_node));
303
304                 ACPI_REPORT_ERROR(("ns_search_and_enter: Null parameter\n"));
305                 return_ACPI_STATUS(AE_BAD_PARAMETER);
306         }
307
308         /* Name must consist of printable characters */
309
310         if (!acpi_ut_valid_acpi_name(target_name)) {
311                 ACPI_REPORT_ERROR(("ns_search_and_enter: Bad character in ACPI Name: %X\n", target_name));
312                 return_ACPI_STATUS(AE_BAD_CHARACTER);
313         }
314
315         /* Try to find the name in the namespace level specified by the caller */
316
317         *return_node = ACPI_ENTRY_NOT_FOUND;
318         status = acpi_ns_search_node(target_name, node, type, return_node);
319         if (status != AE_NOT_FOUND) {
320                 /*
321                  * If we found it AND the request specifies that a find is an error,
322                  * return the error
323                  */
324                 if ((status == AE_OK) && (flags & ACPI_NS_ERROR_IF_FOUND)) {
325                         status = AE_ALREADY_EXISTS;
326                 }
327
328                 /*
329                  * Either found it or there was an error
330                  * -- finished either way
331                  */
332                 return_ACPI_STATUS(status);
333         }
334
335         /*
336          * The name was not found.  If we are NOT performing the first pass
337          * (name entry) of loading the namespace, search the parent tree (all the
338          * way to the root if necessary.) We don't want to perform the parent
339          * search when the namespace is actually being loaded.  We want to perform
340          * the search when namespace references are being resolved (load pass 2)
341          * and during the execution phase.
342          */
343         if ((interpreter_mode != ACPI_IMODE_LOAD_PASS1) &&
344             (flags & ACPI_NS_SEARCH_PARENT)) {
345                 /*
346                  * Not found at this level - search parent tree according to the
347                  * ACPI specification
348                  */
349                 status =
350                     acpi_ns_search_parent_tree(target_name, node, type,
351                                                return_node);
352                 if (ACPI_SUCCESS(status)) {
353                         return_ACPI_STATUS(status);
354                 }
355         }
356
357         /*
358          * In execute mode, just search, never add names.  Exit now.
359          */
360         if (interpreter_mode == ACPI_IMODE_EXECUTE) {
361                 ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
362                                   "%4.4s Not found in %p [Not adding]\n",
363                                   (char *)&target_name, node));
364
365                 return_ACPI_STATUS(AE_NOT_FOUND);
366         }
367
368         /* Create the new named object */
369
370         new_node = acpi_ns_create_node(target_name);
371         if (!new_node) {
372                 return_ACPI_STATUS(AE_NO_MEMORY);
373         }
374
375         /* Install the new object into the parent's list of children */
376
377         acpi_ns_install_node(walk_state, node, new_node, type);
378         *return_node = new_node;
379
380         return_ACPI_STATUS(AE_OK);
381 }