Merge branch 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux...
[linux-2.6] / drivers / acpi / acpica / nssearch.c
1 /*******************************************************************************
2  *
3  * Module Name: nssearch - Namespace search
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 "accommon.h"
46 #include "acnamesp.h"
47
48 #define _COMPONENT          ACPI_NAMESPACE
49 ACPI_MODULE_NAME("nssearch")
50
51 /* Local prototypes */
52 static acpi_status
53 acpi_ns_search_parent_tree(u32 target_name,
54                            struct acpi_namespace_node *node,
55                            acpi_object_type type,
56                            struct acpi_namespace_node **return_node);
57
58 /*******************************************************************************
59  *
60  * FUNCTION:    acpi_ns_search_one_scope
61  *
62  * PARAMETERS:  target_name     - Ascii ACPI name to search for
63  *              parent_node     - Starting node where search will begin
64  *              Type            - Object type to match
65  *              return_node     - Where the matched Named obj is returned
66  *
67  * RETURN:      Status
68  *
69  * DESCRIPTION: Search a single level of the namespace. Performs a
70  *              simple search of the specified level, and does not add
71  *              entries or search parents.
72  *
73  *
74  *      Named object lists are built (and subsequently dumped) in the
75  *      order in which the names are encountered during the namespace load;
76  *
77  *      All namespace searching is linear in this implementation, but
78  *      could be easily modified to support any improved search
79  *      algorithm. However, the linear search was chosen for simplicity
80  *      and because the trees are small and the other interpreter
81  *      execution overhead is relatively high.
82  *
83  *      Note: CPU execution analysis has shown that the AML interpreter spends
84  *      a very small percentage of its time searching the namespace. Therefore,
85  *      the linear search seems to be sufficient, as there would seem to be
86  *      little value in improving the search.
87  *
88  ******************************************************************************/
89
90 acpi_status
91 acpi_ns_search_one_scope(u32 target_name,
92                          struct acpi_namespace_node *parent_node,
93                          acpi_object_type type,
94                          struct acpi_namespace_node **return_node)
95 {
96         struct acpi_namespace_node *node;
97
98         ACPI_FUNCTION_TRACE(ns_search_one_scope);
99
100 #ifdef ACPI_DEBUG_OUTPUT
101         if (ACPI_LV_NAMES & acpi_dbg_level) {
102                 char *scope_name;
103
104                 scope_name = acpi_ns_get_external_pathname(parent_node);
105                 if (scope_name) {
106                         ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
107                                           "Searching %s (%p) For [%4.4s] (%s)\n",
108                                           scope_name, parent_node,
109                                           ACPI_CAST_PTR(char, &target_name),
110                                           acpi_ut_get_type_name(type)));
111
112                         ACPI_FREE(scope_name);
113                 }
114         }
115 #endif
116
117         /*
118          * Search for name at this namespace level, which is to say that we
119          * must search for the name among the children of this object
120          */
121         node = parent_node->child;
122         while (node) {
123
124                 /* Check for match against the name */
125
126                 if (node->name.integer == target_name) {
127
128                         /* Resolve a control method alias if any */
129
130                         if (acpi_ns_get_type(node) ==
131                             ACPI_TYPE_LOCAL_METHOD_ALIAS) {
132                                 node =
133                                     ACPI_CAST_PTR(struct acpi_namespace_node,
134                                                   node->object);
135                         }
136
137                         /* Found matching entry */
138
139                         ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
140                                           "Name [%4.4s] (%s) %p found in scope [%4.4s] %p\n",
141                                           ACPI_CAST_PTR(char, &target_name),
142                                           acpi_ut_get_type_name(node->type),
143                                           node,
144                                           acpi_ut_get_node_name(parent_node),
145                                           parent_node));
146
147                         *return_node = node;
148                         return_ACPI_STATUS(AE_OK);
149                 }
150
151                 /*
152                  * The last entry in the list points back to the parent,
153                  * so a flag is used to indicate the end-of-list
154                  */
155                 if (node->flags & ANOBJ_END_OF_PEER_LIST) {
156
157                         /* Searched entire list, we are done */
158
159                         break;
160                 }
161
162                 /* Didn't match name, move on to the next peer object */
163
164                 node = node->peer;
165         }
166
167         /* Searched entire namespace level, not found */
168
169         ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
170                           "Name [%4.4s] (%s) not found in search in scope [%4.4s] %p first child %p\n",
171                           ACPI_CAST_PTR(char, &target_name),
172                           acpi_ut_get_type_name(type),
173                           acpi_ut_get_node_name(parent_node), parent_node,
174                           parent_node->child));
175
176         return_ACPI_STATUS(AE_NOT_FOUND);
177 }
178
179 /*******************************************************************************
180  *
181  * FUNCTION:    acpi_ns_search_parent_tree
182  *
183  * PARAMETERS:  target_name     - Ascii ACPI name to search for
184  *              Node            - Starting node where search will begin
185  *              Type            - Object type to match
186  *              return_node     - Where the matched Node is returned
187  *
188  * RETURN:      Status
189  *
190  * DESCRIPTION: Called when a name has not been found in the current namespace
191  *              level. Before adding it or giving up, ACPI scope rules require
192  *              searching enclosing scopes in cases identified by acpi_ns_local().
193  *
194  *              "A name is located by finding the matching name in the current
195  *              name space, and then in the parent name space. If the parent
196  *              name space does not contain the name, the search continues
197  *              recursively until either the name is found or the name space
198  *              does not have a parent (the root of the name space). This
199  *              indicates that the name is not found" (From ACPI Specification,
200  *              section 5.3)
201  *
202  ******************************************************************************/
203
204 static acpi_status
205 acpi_ns_search_parent_tree(u32 target_name,
206                            struct acpi_namespace_node *node,
207                            acpi_object_type type,
208                            struct acpi_namespace_node **return_node)
209 {
210         acpi_status status;
211         struct acpi_namespace_node *parent_node;
212
213         ACPI_FUNCTION_TRACE(ns_search_parent_tree);
214
215         parent_node = acpi_ns_get_parent_node(node);
216
217         /*
218          * If there is no parent (i.e., we are at the root) or type is "local",
219          * we won't be searching the parent tree.
220          */
221         if (!parent_node) {
222                 ACPI_DEBUG_PRINT((ACPI_DB_NAMES, "[%4.4s] has no parent\n",
223                                   ACPI_CAST_PTR(char, &target_name)));
224                 return_ACPI_STATUS(AE_NOT_FOUND);
225         }
226
227         if (acpi_ns_local(type)) {
228                 ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
229                                   "[%4.4s] type [%s] must be local to this scope (no parent search)\n",
230                                   ACPI_CAST_PTR(char, &target_name),
231                                   acpi_ut_get_type_name(type)));
232                 return_ACPI_STATUS(AE_NOT_FOUND);
233         }
234
235         /* Search the parent tree */
236
237         ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
238                           "Searching parent [%4.4s] for [%4.4s]\n",
239                           acpi_ut_get_node_name(parent_node),
240                           ACPI_CAST_PTR(char, &target_name)));
241
242         /*
243          * Search parents until target is found or we have backed up to the root
244          */
245         while (parent_node) {
246                 /*
247                  * Search parent scope. Use TYPE_ANY because we don't care about the
248                  * object type at this point, we only care about the existence of
249                  * the actual name we are searching for. Typechecking comes later.
250                  */
251                 status =
252                     acpi_ns_search_one_scope(target_name, parent_node,
253                                              ACPI_TYPE_ANY, return_node);
254                 if (ACPI_SUCCESS(status)) {
255                         return_ACPI_STATUS(status);
256                 }
257
258                 /* Not found here, go up another level (until we reach the root) */
259
260                 parent_node = acpi_ns_get_parent_node(parent_node);
261         }
262
263         /* Not found in parent tree */
264
265         return_ACPI_STATUS(AE_NOT_FOUND);
266 }
267
268 /*******************************************************************************
269  *
270  * FUNCTION:    acpi_ns_search_and_enter
271  *
272  * PARAMETERS:  target_name         - Ascii ACPI name to search for (4 chars)
273  *              walk_state          - Current state of the walk
274  *              Node                - Starting node where search will begin
275  *              interpreter_mode    - Add names only in ACPI_MODE_LOAD_PASS_x.
276  *                                    Otherwise,search only.
277  *              Type                - Object type to match
278  *              Flags               - Flags describing the search restrictions
279  *              return_node         - Where the Node is returned
280  *
281  * RETURN:      Status
282  *
283  * DESCRIPTION: Search for a name segment in a single namespace level,
284  *              optionally adding it if it is not found. If the passed
285  *              Type is not Any and the type previously stored in the
286  *              entry was Any (i.e. unknown), update the stored type.
287  *
288  *              In ACPI_IMODE_EXECUTE, search only.
289  *              In other modes, search and add if not found.
290  *
291  ******************************************************************************/
292
293 acpi_status
294 acpi_ns_search_and_enter(u32 target_name,
295                          struct acpi_walk_state *walk_state,
296                          struct acpi_namespace_node *node,
297                          acpi_interpreter_mode interpreter_mode,
298                          acpi_object_type type,
299                          u32 flags, struct acpi_namespace_node **return_node)
300 {
301         acpi_status status;
302         struct acpi_namespace_node *new_node;
303
304         ACPI_FUNCTION_TRACE(ns_search_and_enter);
305
306         /* Parameter validation */
307
308         if (!node || !target_name || !return_node) {
309                 ACPI_ERROR((AE_INFO,
310                             "Null parameter: Node %p Name %X ReturnNode %p",
311                             node, target_name, return_node));
312                 return_ACPI_STATUS(AE_BAD_PARAMETER);
313         }
314
315         /*
316          * Name must consist of valid ACPI characters. We will repair the name if
317          * necessary because we don't want to abort because of this, but we want
318          * all namespace names to be printable. A warning message is appropriate.
319          *
320          * This issue came up because there are in fact machines that exhibit
321          * this problem, and we want to be able to enable ACPI support for them,
322          * even though there are a few bad names.
323          */
324         if (!acpi_ut_valid_acpi_name(target_name)) {
325                 target_name =
326                     acpi_ut_repair_name(ACPI_CAST_PTR(char, &target_name));
327
328                 /* Report warning only if in strict mode or debug mode */
329
330                 if (!acpi_gbl_enable_interpreter_slack) {
331                         ACPI_WARNING((AE_INFO,
332                                       "Found bad character(s) in name, repaired: [%4.4s]\n",
333                                       ACPI_CAST_PTR(char, &target_name)));
334                 } else {
335                         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
336                                           "Found bad character(s) in name, repaired: [%4.4s]\n",
337                                           ACPI_CAST_PTR(char, &target_name)));
338                 }
339         }
340
341         /* Try to find the name in the namespace level specified by the caller */
342
343         *return_node = ACPI_ENTRY_NOT_FOUND;
344         status = acpi_ns_search_one_scope(target_name, node, type, return_node);
345         if (status != AE_NOT_FOUND) {
346                 /*
347                  * If we found it AND the request specifies that a find is an error,
348                  * return the error
349                  */
350                 if ((status == AE_OK) && (flags & ACPI_NS_ERROR_IF_FOUND)) {
351                         status = AE_ALREADY_EXISTS;
352                 }
353
354                 /* Either found it or there was an error: finished either way */
355
356                 return_ACPI_STATUS(status);
357         }
358
359         /*
360          * The name was not found. If we are NOT performing the first pass
361          * (name entry) of loading the namespace, search the parent tree (all the
362          * way to the root if necessary.) We don't want to perform the parent
363          * search when the namespace is actually being loaded. We want to perform
364          * the search when namespace references are being resolved (load pass 2)
365          * and during the execution phase.
366          */
367         if ((interpreter_mode != ACPI_IMODE_LOAD_PASS1) &&
368             (flags & ACPI_NS_SEARCH_PARENT)) {
369                 /*
370                  * Not found at this level - search parent tree according to the
371                  * ACPI specification
372                  */
373                 status =
374                     acpi_ns_search_parent_tree(target_name, node, type,
375                                                return_node);
376                 if (ACPI_SUCCESS(status)) {
377                         return_ACPI_STATUS(status);
378                 }
379         }
380
381         /* In execute mode, just search, never add names. Exit now */
382
383         if (interpreter_mode == ACPI_IMODE_EXECUTE) {
384                 ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
385                                   "%4.4s Not found in %p [Not adding]\n",
386                                   ACPI_CAST_PTR(char, &target_name), node));
387
388                 return_ACPI_STATUS(AE_NOT_FOUND);
389         }
390
391         /* Create the new named object */
392
393         new_node = acpi_ns_create_node(target_name);
394         if (!new_node) {
395                 return_ACPI_STATUS(AE_NO_MEMORY);
396         }
397 #ifdef ACPI_ASL_COMPILER
398         /*
399          * Node is an object defined by an External() statement
400          */
401         if (flags & ACPI_NS_EXTERNAL) {
402                 new_node->flags |= ANOBJ_IS_EXTERNAL;
403         }
404 #endif
405
406         if (flags & ACPI_NS_TEMPORARY) {
407                 new_node->flags |= ANOBJ_TEMPORARY;
408         }
409
410         /* Install the new object into the parent's list of children */
411
412         acpi_ns_install_node(walk_state, node, new_node, type);
413         *return_node = new_node;
414         return_ACPI_STATUS(AE_OK);
415 }