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[reactos.git] / drivers / bus / acpi / acpica / namespace / nsaccess.c
1 /*******************************************************************************
2 *
3 * Module Name: nsaccess - Top-level functions for accessing ACPI namespace
4 *
5 ******************************************************************************/
6
7 /******************************************************************************
8 *
9 * 1. Copyright Notice
10 *
11 * Some or all of this work - Copyright (c) 1999 - 2009, Intel Corp.
12 * All rights reserved.
13 *
14 * 2. License
15 *
16 * 2.1. This is your license from Intel Corp. under its intellectual property
17 * rights. You may have additional license terms from the party that provided
18 * you this software, covering your right to use that party's intellectual
19 * property rights.
20 *
21 * 2.2. Intel grants, free of charge, to any person ("Licensee") obtaining a
22 * copy of the source code appearing in this file ("Covered Code") an
23 * irrevocable, perpetual, worldwide license under Intel's copyrights in the
24 * base code distributed originally by Intel ("Original Intel Code") to copy,
25 * make derivatives, distribute, use and display any portion of the Covered
26 * Code in any form, with the right to sublicense such rights; and
27 *
28 * 2.3. Intel grants Licensee a non-exclusive and non-transferable patent
29 * license (with the right to sublicense), under only those claims of Intel
30 * patents that are infringed by the Original Intel Code, to make, use, sell,
31 * offer to sell, and import the Covered Code and derivative works thereof
32 * solely to the minimum extent necessary to exercise the above copyright
33 * license, and in no event shall the patent license extend to any additions
34 * to or modifications of the Original Intel Code. No other license or right
35 * is granted directly or by implication, estoppel or otherwise;
36 *
37 * The above copyright and patent license is granted only if the following
38 * conditions are met:
39 *
40 * 3. Conditions
41 *
42 * 3.1. Redistribution of Source with Rights to Further Distribute Source.
43 * Redistribution of source code of any substantial portion of the Covered
44 * Code or modification with rights to further distribute source must include
45 * the above Copyright Notice, the above License, this list of Conditions,
46 * and the following Disclaimer and Export Compliance provision. In addition,
47 * Licensee must cause all Covered Code to which Licensee contributes to
48 * contain a file documenting the changes Licensee made to create that Covered
49 * Code and the date of any change. Licensee must include in that file the
50 * documentation of any changes made by any predecessor Licensee. Licensee
51 * must include a prominent statement that the modification is derived,
52 * directly or indirectly, from Original Intel Code.
53 *
54 * 3.2. Redistribution of Source with no Rights to Further Distribute Source.
55 * Redistribution of source code of any substantial portion of the Covered
56 * Code or modification without rights to further distribute source must
57 * include the following Disclaimer and Export Compliance provision in the
58 * documentation and/or other materials provided with distribution. In
59 * addition, Licensee may not authorize further sublicense of source of any
60 * portion of the Covered Code, and must include terms to the effect that the
61 * license from Licensee to its licensee is limited to the intellectual
62 * property embodied in the software Licensee provides to its licensee, and
63 * not to intellectual property embodied in modifications its licensee may
64 * make.
65 *
66 * 3.3. Redistribution of Executable. Redistribution in executable form of any
67 * substantial portion of the Covered Code or modification must reproduce the
68 * above Copyright Notice, and the following Disclaimer and Export Compliance
69 * provision in the documentation and/or other materials provided with the
70 * distribution.
71 *
72 * 3.4. Intel retains all right, title, and interest in and to the Original
73 * Intel Code.
74 *
75 * 3.5. Neither the name Intel nor any other trademark owned or controlled by
76 * Intel shall be used in advertising or otherwise to promote the sale, use or
77 * other dealings in products derived from or relating to the Covered Code
78 * without prior written authorization from Intel.
79 *
80 * 4. Disclaimer and Export Compliance
81 *
82 * 4.1. INTEL MAKES NO WARRANTY OF ANY KIND REGARDING ANY SOFTWARE PROVIDED
83 * HERE. ANY SOFTWARE ORIGINATING FROM INTEL OR DERIVED FROM INTEL SOFTWARE
84 * IS PROVIDED "AS IS," AND INTEL WILL NOT PROVIDE ANY SUPPORT, ASSISTANCE,
85 * INSTALLATION, TRAINING OR OTHER SERVICES. INTEL WILL NOT PROVIDE ANY
86 * UPDATES, ENHANCEMENTS OR EXTENSIONS. INTEL SPECIFICALLY DISCLAIMS ANY
87 * IMPLIED WARRANTIES OF MERCHANTABILITY, NONINFRINGEMENT AND FITNESS FOR A
88 * PARTICULAR PURPOSE.
89 *
90 * 4.2. IN NO EVENT SHALL INTEL HAVE ANY LIABILITY TO LICENSEE, ITS LICENSEES
91 * OR ANY OTHER THIRD PARTY, FOR ANY LOST PROFITS, LOST DATA, LOSS OF USE OR
92 * COSTS OF PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES, OR FOR ANY INDIRECT,
93 * SPECIAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THIS AGREEMENT, UNDER ANY
94 * CAUSE OF ACTION OR THEORY OF LIABILITY, AND IRRESPECTIVE OF WHETHER INTEL
95 * HAS ADVANCE NOTICE OF THE POSSIBILITY OF SUCH DAMAGES. THESE LIMITATIONS
96 * SHALL APPLY NOTWITHSTANDING THE FAILURE OF THE ESSENTIAL PURPOSE OF ANY
97 * LIMITED REMEDY.
98 *
99 * 4.3. Licensee shall not export, either directly or indirectly, any of this
100 * software or system incorporating such software without first obtaining any
101 * required license or other approval from the U. S. Department of Commerce or
102 * any other agency or department of the United States Government. In the
103 * event Licensee exports any such software from the United States or
104 * re-exports any such software from a foreign destination, Licensee shall
105 * ensure that the distribution and export/re-export of the software is in
106 * compliance with all laws, regulations, orders, or other restrictions of the
107 * U.S. Export Administration Regulations. Licensee agrees that neither it nor
108 * any of its subsidiaries will export/re-export any technical data, process,
109 * software, or service, directly or indirectly, to any country for which the
110 * United States government or any agency thereof requires an export license,
111 * other governmental approval, or letter of assurance, without first obtaining
112 * such license, approval or letter.
113 *
114 *****************************************************************************/
115
116 #define __NSACCESS_C__
117
118 #include "acpi.h"
119 #include "accommon.h"
120 #include "amlcode.h"
121 #include "acnamesp.h"
122 #include "acdispat.h"
123
124
125 #define _COMPONENT ACPI_NAMESPACE
126 ACPI_MODULE_NAME ("nsaccess")
127
128
129 /*******************************************************************************
130 *
131 * FUNCTION: AcpiNsRootInitialize
132 *
133 * PARAMETERS: None
134 *
135 * RETURN: Status
136 *
137 * DESCRIPTION: Allocate and initialize the default root named objects
138 *
139 * MUTEX: Locks namespace for entire execution
140 *
141 ******************************************************************************/
142
143 ACPI_STATUS
144 AcpiNsRootInitialize (
145 void)
146 {
147 ACPI_STATUS Status;
148 const ACPI_PREDEFINED_NAMES *InitVal = NULL;
149 ACPI_NAMESPACE_NODE *NewNode;
150 ACPI_OPERAND_OBJECT *ObjDesc;
151 ACPI_STRING Val = NULL;
152
153
154 ACPI_FUNCTION_TRACE (NsRootInitialize);
155
156
157 Status = AcpiUtAcquireMutex (ACPI_MTX_NAMESPACE);
158 if (ACPI_FAILURE (Status))
159 {
160 return_ACPI_STATUS (Status);
161 }
162
163 /*
164 * The global root ptr is initially NULL, so a non-NULL value indicates
165 * that AcpiNsRootInitialize() has already been called; just return.
166 */
167 if (AcpiGbl_RootNode)
168 {
169 Status = AE_OK;
170 goto UnlockAndExit;
171 }
172
173 /*
174 * Tell the rest of the subsystem that the root is initialized
175 * (This is OK because the namespace is locked)
176 */
177 AcpiGbl_RootNode = &AcpiGbl_RootNodeStruct;
178
179 /* Enter the pre-defined names in the name table */
180
181 ACPI_DEBUG_PRINT ((ACPI_DB_INFO,
182 "Entering predefined entries into namespace\n"));
183
184 for (InitVal = AcpiGbl_PreDefinedNames; InitVal->Name; InitVal++)
185 {
186 /* _OSI is optional for now, will be permanent later */
187
188 if (!ACPI_STRCMP (InitVal->Name, "_OSI") && !AcpiGbl_CreateOsiMethod)
189 {
190 continue;
191 }
192
193 Status = AcpiNsLookup (NULL, InitVal->Name, InitVal->Type,
194 ACPI_IMODE_LOAD_PASS2, ACPI_NS_NO_UPSEARCH,
195 NULL, &NewNode);
196
197 if (ACPI_FAILURE (Status) || (!NewNode)) /* Must be on same line for code converter */
198 {
199 ACPI_EXCEPTION ((AE_INFO, Status,
200 "Could not create predefined name %s",
201 InitVal->Name));
202 }
203
204 /*
205 * Name entered successfully. If entry in PreDefinedNames[] specifies
206 * an initial value, create the initial value.
207 */
208 if (InitVal->Val)
209 {
210 Status = AcpiOsPredefinedOverride (InitVal, &Val);
211 if (ACPI_FAILURE (Status))
212 {
213 ACPI_ERROR ((AE_INFO,
214 "Could not override predefined %s",
215 InitVal->Name));
216 }
217
218 if (!Val)
219 {
220 Val = InitVal->Val;
221 }
222
223 /*
224 * Entry requests an initial value, allocate a
225 * descriptor for it.
226 */
227 ObjDesc = AcpiUtCreateInternalObject (InitVal->Type);
228 if (!ObjDesc)
229 {
230 Status = AE_NO_MEMORY;
231 goto UnlockAndExit;
232 }
233
234 /*
235 * Convert value string from table entry to
236 * internal representation. Only types actually
237 * used for initial values are implemented here.
238 */
239 switch (InitVal->Type)
240 {
241 case ACPI_TYPE_METHOD:
242 ObjDesc->Method.ParamCount = (UINT8) ACPI_TO_INTEGER (Val);
243 ObjDesc->Common.Flags |= AOPOBJ_DATA_VALID;
244
245 #if defined (ACPI_ASL_COMPILER)
246
247 /* Save the parameter count for the iASL compiler */
248
249 NewNode->Value = ObjDesc->Method.ParamCount;
250 #else
251 /* Mark this as a very SPECIAL method */
252
253 ObjDesc->Method.MethodFlags = AML_METHOD_INTERNAL_ONLY;
254 ObjDesc->Method.Extra.Implementation = AcpiUtOsiImplementation;
255 #endif
256 break;
257
258 case ACPI_TYPE_INTEGER:
259
260 ObjDesc->Integer.Value = ACPI_TO_INTEGER (Val);
261 break;
262
263
264 case ACPI_TYPE_STRING:
265
266 /* Build an object around the static string */
267
268 ObjDesc->String.Length = (UINT32) ACPI_STRLEN (Val);
269 ObjDesc->String.Pointer = Val;
270 ObjDesc->Common.Flags |= AOPOBJ_STATIC_POINTER;
271 break;
272
273
274 case ACPI_TYPE_MUTEX:
275
276 ObjDesc->Mutex.Node = NewNode;
277 ObjDesc->Mutex.SyncLevel = (UINT8) (ACPI_TO_INTEGER (Val) - 1);
278
279 /* Create a mutex */
280
281 Status = AcpiOsCreateMutex (&ObjDesc->Mutex.OsMutex);
282 if (ACPI_FAILURE (Status))
283 {
284 AcpiUtRemoveReference (ObjDesc);
285 goto UnlockAndExit;
286 }
287
288 /* Special case for ACPI Global Lock */
289
290 if (ACPI_STRCMP (InitVal->Name, "_GL_") == 0)
291 {
292 AcpiGbl_GlobalLockMutex = ObjDesc;
293
294 /* Create additional counting semaphore for global lock */
295
296 Status = AcpiOsCreateSemaphore (
297 1, 0, &AcpiGbl_GlobalLockSemaphore);
298 if (ACPI_FAILURE (Status))
299 {
300 AcpiUtRemoveReference (ObjDesc);
301 goto UnlockAndExit;
302 }
303 }
304 break;
305
306
307 default:
308
309 ACPI_ERROR ((AE_INFO, "Unsupported initial type value %X",
310 InitVal->Type));
311 AcpiUtRemoveReference (ObjDesc);
312 ObjDesc = NULL;
313 continue;
314 }
315
316 /* Store pointer to value descriptor in the Node */
317
318 Status = AcpiNsAttachObject (NewNode, ObjDesc,
319 ObjDesc->Common.Type);
320
321 /* Remove local reference to the object */
322
323 AcpiUtRemoveReference (ObjDesc);
324 }
325 }
326
327
328 UnlockAndExit:
329 (void) AcpiUtReleaseMutex (ACPI_MTX_NAMESPACE);
330
331 /* Save a handle to "_GPE", it is always present */
332
333 if (ACPI_SUCCESS (Status))
334 {
335 Status = AcpiNsGetNode (NULL, "\\_GPE", ACPI_NS_NO_UPSEARCH,
336 &AcpiGbl_FadtGpeDevice);
337 }
338
339 return_ACPI_STATUS (Status);
340 }
341
342
343 /*******************************************************************************
344 *
345 * FUNCTION: AcpiNsLookup
346 *
347 * PARAMETERS: ScopeInfo - Current scope info block
348 * Pathname - Search pathname, in internal format
349 * (as represented in the AML stream)
350 * Type - Type associated with name
351 * InterpreterMode - IMODE_LOAD_PASS2 => add name if not found
352 * Flags - Flags describing the search restrictions
353 * WalkState - Current state of the walk
354 * ReturnNode - Where the Node is placed (if found
355 * or created successfully)
356 *
357 * RETURN: Status
358 *
359 * DESCRIPTION: Find or enter the passed name in the name space.
360 * Log an error if name not found in Exec mode.
361 *
362 * MUTEX: Assumes namespace is locked.
363 *
364 ******************************************************************************/
365
366 ACPI_STATUS
367 AcpiNsLookup (
368 ACPI_GENERIC_STATE *ScopeInfo,
369 char *Pathname,
370 ACPI_OBJECT_TYPE Type,
371 ACPI_INTERPRETER_MODE InterpreterMode,
372 UINT32 Flags,
373 ACPI_WALK_STATE *WalkState,
374 ACPI_NAMESPACE_NODE **ReturnNode)
375 {
376 ACPI_STATUS Status;
377 char *Path = Pathname;
378 ACPI_NAMESPACE_NODE *PrefixNode;
379 ACPI_NAMESPACE_NODE *CurrentNode = NULL;
380 ACPI_NAMESPACE_NODE *ThisNode = NULL;
381 UINT32 NumSegments;
382 UINT32 NumCarats;
383 ACPI_NAME SimpleName;
384 ACPI_OBJECT_TYPE TypeToCheckFor;
385 ACPI_OBJECT_TYPE ThisSearchType;
386 UINT32 SearchParentFlag = ACPI_NS_SEARCH_PARENT;
387 UINT32 LocalFlags;
388
389
390 ACPI_FUNCTION_TRACE (NsLookup);
391
392
393 if (!ReturnNode)
394 {
395 return_ACPI_STATUS (AE_BAD_PARAMETER);
396 }
397
398 LocalFlags = Flags & ~(ACPI_NS_ERROR_IF_FOUND | ACPI_NS_SEARCH_PARENT);
399 *ReturnNode = ACPI_ENTRY_NOT_FOUND;
400 AcpiGbl_NsLookupCount++;
401
402 if (!AcpiGbl_RootNode)
403 {
404 return_ACPI_STATUS (AE_NO_NAMESPACE);
405 }
406
407 /* Get the prefix scope. A null scope means use the root scope */
408
409 if ((!ScopeInfo) ||
410 (!ScopeInfo->Scope.Node))
411 {
412 ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
413 "Null scope prefix, using root node (%p)\n",
414 AcpiGbl_RootNode));
415
416 PrefixNode = AcpiGbl_RootNode;
417 }
418 else
419 {
420 PrefixNode = ScopeInfo->Scope.Node;
421 if (ACPI_GET_DESCRIPTOR_TYPE (PrefixNode) != ACPI_DESC_TYPE_NAMED)
422 {
423 ACPI_ERROR ((AE_INFO, "%p is not a namespace node [%s]",
424 PrefixNode, AcpiUtGetDescriptorName (PrefixNode)));
425 return_ACPI_STATUS (AE_AML_INTERNAL);
426 }
427
428 if (!(Flags & ACPI_NS_PREFIX_IS_SCOPE))
429 {
430 /*
431 * This node might not be a actual "scope" node (such as a
432 * Device/Method, etc.) It could be a Package or other object
433 * node. Backup up the tree to find the containing scope node.
434 */
435 while (!AcpiNsOpensScope (PrefixNode->Type) &&
436 PrefixNode->Type != ACPI_TYPE_ANY)
437 {
438 PrefixNode = AcpiNsGetParentNode (PrefixNode);
439 }
440 }
441 }
442
443 /* Save type. TBD: may be no longer necessary */
444
445 TypeToCheckFor = Type;
446
447 /*
448 * Begin examination of the actual pathname
449 */
450 if (!Pathname)
451 {
452 /* A Null NamePath is allowed and refers to the root */
453
454 NumSegments = 0;
455 ThisNode = AcpiGbl_RootNode;
456 Path = "";
457
458 ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
459 "Null Pathname (Zero segments), Flags=%X\n", Flags));
460 }
461 else
462 {
463 /*
464 * Name pointer is valid (and must be in internal name format)
465 *
466 * Check for scope prefixes:
467 *
468 * As represented in the AML stream, a namepath consists of an
469 * optional scope prefix followed by a name segment part.
470 *
471 * If present, the scope prefix is either a Root Prefix (in
472 * which case the name is fully qualified), or one or more
473 * Parent Prefixes (in which case the name's scope is relative
474 * to the current scope).
475 */
476 if (*Path == (UINT8) AML_ROOT_PREFIX)
477 {
478 /* Pathname is fully qualified, start from the root */
479
480 ThisNode = AcpiGbl_RootNode;
481 SearchParentFlag = ACPI_NS_NO_UPSEARCH;
482
483 /* Point to name segment part */
484
485 Path++;
486
487 ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
488 "Path is absolute from root [%p]\n", ThisNode));
489 }
490 else
491 {
492 /* Pathname is relative to current scope, start there */
493
494 ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
495 "Searching relative to prefix scope [%4.4s] (%p)\n",
496 AcpiUtGetNodeName (PrefixNode), PrefixNode));
497
498 /*
499 * Handle multiple Parent Prefixes (carat) by just getting
500 * the parent node for each prefix instance.
501 */
502 ThisNode = PrefixNode;
503 NumCarats = 0;
504 while (*Path == (UINT8) AML_PARENT_PREFIX)
505 {
506 /* Name is fully qualified, no search rules apply */
507
508 SearchParentFlag = ACPI_NS_NO_UPSEARCH;
509
510 /*
511 * Point past this prefix to the name segment
512 * part or the next Parent Prefix
513 */
514 Path++;
515
516 /* Backup to the parent node */
517
518 NumCarats++;
519 ThisNode = AcpiNsGetParentNode (ThisNode);
520 if (!ThisNode)
521 {
522 /* Current scope has no parent scope */
523
524 ACPI_ERROR ((AE_INFO,
525 "ACPI path has too many parent prefixes (^) "
526 "- reached beyond root node"));
527 return_ACPI_STATUS (AE_NOT_FOUND);
528 }
529 }
530
531 if (SearchParentFlag == ACPI_NS_NO_UPSEARCH)
532 {
533 ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
534 "Search scope is [%4.4s], path has %d carat(s)\n",
535 AcpiUtGetNodeName (ThisNode), NumCarats));
536 }
537 }
538
539 /*
540 * Determine the number of ACPI name segments in this pathname.
541 *
542 * The segment part consists of either:
543 * - A Null name segment (0)
544 * - A DualNamePrefix followed by two 4-byte name segments
545 * - A MultiNamePrefix followed by a byte indicating the
546 * number of segments and the segments themselves.
547 * - A single 4-byte name segment
548 *
549 * Examine the name prefix opcode, if any, to determine the number of
550 * segments.
551 */
552 switch (*Path)
553 {
554 case 0:
555 /*
556 * Null name after a root or parent prefixes. We already
557 * have the correct target node and there are no name segments.
558 */
559 NumSegments = 0;
560 Type = ThisNode->Type;
561
562 ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
563 "Prefix-only Pathname (Zero name segments), Flags=%X\n",
564 Flags));
565 break;
566
567 case AML_DUAL_NAME_PREFIX:
568
569 /* More than one NameSeg, search rules do not apply */
570
571 SearchParentFlag = ACPI_NS_NO_UPSEARCH;
572
573 /* Two segments, point to first name segment */
574
575 NumSegments = 2;
576 Path++;
577
578 ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
579 "Dual Pathname (2 segments, Flags=%X)\n", Flags));
580 break;
581
582 case AML_MULTI_NAME_PREFIX_OP:
583
584 /* More than one NameSeg, search rules do not apply */
585
586 SearchParentFlag = ACPI_NS_NO_UPSEARCH;
587
588 /* Extract segment count, point to first name segment */
589
590 Path++;
591 NumSegments = (UINT32) (UINT8) *Path;
592 Path++;
593
594 ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
595 "Multi Pathname (%d Segments, Flags=%X)\n",
596 NumSegments, Flags));
597 break;
598
599 default:
600 /*
601 * Not a Null name, no Dual or Multi prefix, hence there is
602 * only one name segment and Pathname is already pointing to it.
603 */
604 NumSegments = 1;
605
606 ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
607 "Simple Pathname (1 segment, Flags=%X)\n", Flags));
608 break;
609 }
610
611 ACPI_DEBUG_EXEC (AcpiNsPrintPathname (NumSegments, Path));
612 }
613
614
615 /*
616 * Search namespace for each segment of the name. Loop through and
617 * verify (or add to the namespace) each name segment.
618 *
619 * The object type is significant only at the last name
620 * segment. (We don't care about the types along the path, only
621 * the type of the final target object.)
622 */
623 ThisSearchType = ACPI_TYPE_ANY;
624 CurrentNode = ThisNode;
625 while (NumSegments && CurrentNode)
626 {
627 NumSegments--;
628 if (!NumSegments)
629 {
630 /* This is the last segment, enable typechecking */
631
632 ThisSearchType = Type;
633
634 /*
635 * Only allow automatic parent search (search rules) if the caller
636 * requested it AND we have a single, non-fully-qualified NameSeg
637 */
638 if ((SearchParentFlag != ACPI_NS_NO_UPSEARCH) &&
639 (Flags & ACPI_NS_SEARCH_PARENT))
640 {
641 LocalFlags |= ACPI_NS_SEARCH_PARENT;
642 }
643
644 /* Set error flag according to caller */
645
646 if (Flags & ACPI_NS_ERROR_IF_FOUND)
647 {
648 LocalFlags |= ACPI_NS_ERROR_IF_FOUND;
649 }
650 }
651
652 /* Extract one ACPI name from the front of the pathname */
653
654 ACPI_MOVE_32_TO_32 (&SimpleName, Path);
655
656 /* Try to find the single (4 character) ACPI name */
657
658 Status = AcpiNsSearchAndEnter (SimpleName, WalkState, CurrentNode,
659 InterpreterMode, ThisSearchType, LocalFlags, &ThisNode);
660 if (ACPI_FAILURE (Status))
661 {
662 if (Status == AE_NOT_FOUND)
663 {
664 /* Name not found in ACPI namespace */
665
666 ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
667 "Name [%4.4s] not found in scope [%4.4s] %p\n",
668 (char *) &SimpleName, (char *) &CurrentNode->Name,
669 CurrentNode));
670 }
671
672 *ReturnNode = ThisNode;
673 return_ACPI_STATUS (Status);
674 }
675
676 /* More segments to follow? */
677
678 if (NumSegments > 0)
679 {
680 /*
681 * If we have an alias to an object that opens a scope (such as a
682 * device or processor), we need to dereference the alias here so
683 * that we can access any children of the original node (via the
684 * remaining segments).
685 */
686 if (ThisNode->Type == ACPI_TYPE_LOCAL_ALIAS)
687 {
688 if (!ThisNode->Object)
689 {
690 return_ACPI_STATUS (AE_NOT_EXIST);
691 }
692
693 if (AcpiNsOpensScope (((ACPI_NAMESPACE_NODE *)
694 ThisNode->Object)->Type))
695 {
696 ThisNode = (ACPI_NAMESPACE_NODE *) ThisNode->Object;
697 }
698 }
699 }
700
701 /* Special handling for the last segment (NumSegments == 0) */
702
703 else
704 {
705 /*
706 * Sanity typecheck of the target object:
707 *
708 * If 1) This is the last segment (NumSegments == 0)
709 * 2) And we are looking for a specific type
710 * (Not checking for TYPE_ANY)
711 * 3) Which is not an alias
712 * 4) Which is not a local type (TYPE_SCOPE)
713 * 5) And the type of target object is known (not TYPE_ANY)
714 * 6) And target object does not match what we are looking for
715 *
716 * Then we have a type mismatch. Just warn and ignore it.
717 */
718 if ((TypeToCheckFor != ACPI_TYPE_ANY) &&
719 (TypeToCheckFor != ACPI_TYPE_LOCAL_ALIAS) &&
720 (TypeToCheckFor != ACPI_TYPE_LOCAL_METHOD_ALIAS) &&
721 (TypeToCheckFor != ACPI_TYPE_LOCAL_SCOPE) &&
722 (ThisNode->Type != ACPI_TYPE_ANY) &&
723 (ThisNode->Type != TypeToCheckFor))
724 {
725 /* Complain about a type mismatch */
726
727 ACPI_WARNING ((AE_INFO,
728 "NsLookup: Type mismatch on %4.4s (%s), searching for (%s)",
729 ACPI_CAST_PTR (char, &SimpleName),
730 AcpiUtGetTypeName (ThisNode->Type),
731 AcpiUtGetTypeName (TypeToCheckFor)));
732 }
733
734 /*
735 * If this is the last name segment and we are not looking for a
736 * specific type, but the type of found object is known, use that
737 * type to (later) see if it opens a scope.
738 */
739 if (Type == ACPI_TYPE_ANY)
740 {
741 Type = ThisNode->Type;
742 }
743 }
744
745 /* Point to next name segment and make this node current */
746
747 Path += ACPI_NAME_SIZE;
748 CurrentNode = ThisNode;
749 }
750
751 /* Always check if we need to open a new scope */
752
753 if (!(Flags & ACPI_NS_DONT_OPEN_SCOPE) && (WalkState))
754 {
755 /*
756 * If entry is a type which opens a scope, push the new scope on the
757 * scope stack.
758 */
759 if (AcpiNsOpensScope (Type))
760 {
761 Status = AcpiDsScopeStackPush (ThisNode, Type, WalkState);
762 if (ACPI_FAILURE (Status))
763 {
764 return_ACPI_STATUS (Status);
765 }
766 }
767 }
768
769 *ReturnNode = ThisNode;
770 return_ACPI_STATUS (AE_OK);
771 }
772