xref: /titanic_41/usr/src/uts/intel/io/acpica/namespace/nsaccess.c (revision e11c3f44f531fdff80941ce57c065d2ae861cefc)
1 /*******************************************************************************
2  *
3  * Module Name: nsaccess - Top-level functions for accessing ACPI namespace
4  *              $Revision: 1.209 $
5  *
6  ******************************************************************************/
7 
8 /******************************************************************************
9  *
10  * 1. Copyright Notice
11  *
12  * Some or all of this work - Copyright (c) 1999 - 2008, Intel Corp.
13  * All rights reserved.
14  *
15  * 2. License
16  *
17  * 2.1. This is your license from Intel Corp. under its intellectual property
18  * rights.  You may have additional license terms from the party that provided
19  * you this software, covering your right to use that party's intellectual
20  * property rights.
21  *
22  * 2.2. Intel grants, free of charge, to any person ("Licensee") obtaining a
23  * copy of the source code appearing in this file ("Covered Code") an
24  * irrevocable, perpetual, worldwide license under Intel's copyrights in the
25  * base code distributed originally by Intel ("Original Intel Code") to copy,
26  * make derivatives, distribute, use and display any portion of the Covered
27  * Code in any form, with the right to sublicense such rights; and
28  *
29  * 2.3. Intel grants Licensee a non-exclusive and non-transferable patent
30  * license (with the right to sublicense), under only those claims of Intel
31  * patents that are infringed by the Original Intel Code, to make, use, sell,
32  * offer to sell, and import the Covered Code and derivative works thereof
33  * solely to the minimum extent necessary to exercise the above copyright
34  * license, and in no event shall the patent license extend to any additions
35  * to or modifications of the Original Intel Code.  No other license or right
36  * is granted directly or by implication, estoppel or otherwise;
37  *
38  * The above copyright and patent license is granted only if the following
39  * conditions are met:
40  *
41  * 3. Conditions
42  *
43  * 3.1. Redistribution of Source with Rights to Further Distribute Source.
44  * Redistribution of source code of any substantial portion of the Covered
45  * Code or modification with rights to further distribute source must include
46  * the above Copyright Notice, the above License, this list of Conditions,
47  * and the following Disclaimer and Export Compliance provision.  In addition,
48  * Licensee must cause all Covered Code to which Licensee contributes to
49  * contain a file documenting the changes Licensee made to create that Covered
50  * Code and the date of any change.  Licensee must include in that file the
51  * documentation of any changes made by any predecessor Licensee.  Licensee
52  * must include a prominent statement that the modification is derived,
53  * directly or indirectly, from Original Intel Code.
54  *
55  * 3.2. Redistribution of Source with no Rights to Further Distribute Source.
56  * Redistribution of source code of any substantial portion of the Covered
57  * Code or modification without rights to further distribute source must
58  * include the following Disclaimer and Export Compliance provision in the
59  * documentation and/or other materials provided with distribution.  In
60  * addition, Licensee may not authorize further sublicense of source of any
61  * portion of the Covered Code, and must include terms to the effect that the
62  * license from Licensee to its licensee is limited to the intellectual
63  * property embodied in the software Licensee provides to its licensee, and
64  * not to intellectual property embodied in modifications its licensee may
65  * make.
66  *
67  * 3.3. Redistribution of Executable. Redistribution in executable form of any
68  * substantial portion of the Covered Code or modification must reproduce the
69  * above Copyright Notice, and the following Disclaimer and Export Compliance
70  * provision in the documentation and/or other materials provided with the
71  * distribution.
72  *
73  * 3.4. Intel retains all right, title, and interest in and to the Original
74  * Intel Code.
75  *
76  * 3.5. Neither the name Intel nor any other trademark owned or controlled by
77  * Intel shall be used in advertising or otherwise to promote the sale, use or
78  * other dealings in products derived from or relating to the Covered Code
79  * without prior written authorization from Intel.
80  *
81  * 4. Disclaimer and Export Compliance
82  *
83  * 4.1. INTEL MAKES NO WARRANTY OF ANY KIND REGARDING ANY SOFTWARE PROVIDED
84  * HERE.  ANY SOFTWARE ORIGINATING FROM INTEL OR DERIVED FROM INTEL SOFTWARE
85  * IS PROVIDED "AS IS," AND INTEL WILL NOT PROVIDE ANY SUPPORT,  ASSISTANCE,
86  * INSTALLATION, TRAINING OR OTHER SERVICES.  INTEL WILL NOT PROVIDE ANY
87  * UPDATES, ENHANCEMENTS OR EXTENSIONS.  INTEL SPECIFICALLY DISCLAIMS ANY
88  * IMPLIED WARRANTIES OF MERCHANTABILITY, NONINFRINGEMENT AND FITNESS FOR A
89  * PARTICULAR PURPOSE.
90  *
91  * 4.2. IN NO EVENT SHALL INTEL HAVE ANY LIABILITY TO LICENSEE, ITS LICENSEES
92  * OR ANY OTHER THIRD PARTY, FOR ANY LOST PROFITS, LOST DATA, LOSS OF USE OR
93  * COSTS OF PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES, OR FOR ANY INDIRECT,
94  * SPECIAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THIS AGREEMENT, UNDER ANY
95  * CAUSE OF ACTION OR THEORY OF LIABILITY, AND IRRESPECTIVE OF WHETHER INTEL
96  * HAS ADVANCE NOTICE OF THE POSSIBILITY OF SUCH DAMAGES.  THESE LIMITATIONS
97  * SHALL APPLY NOTWITHSTANDING THE FAILURE OF THE ESSENTIAL PURPOSE OF ANY
98  * LIMITED REMEDY.
99  *
100  * 4.3. Licensee shall not export, either directly or indirectly, any of this
101  * software or system incorporating such software without first obtaining any
102  * required license or other approval from the U. S. Department of Commerce or
103  * any other agency or department of the United States Government.  In the
104  * event Licensee exports any such software from the United States or
105  * re-exports any such software from a foreign destination, Licensee shall
106  * ensure that the distribution and export/re-export of the software is in
107  * compliance with all laws, regulations, orders, or other restrictions of the
108  * U.S. Export Administration Regulations. Licensee agrees that neither it nor
109  * any of its subsidiaries will export/re-export any technical data, process,
110  * software, or service, directly or indirectly, to any country for which the
111  * United States government or any agency thereof requires an export license,
112  * other governmental approval, or letter of assurance, without first obtaining
113  * such license, approval or letter.
114  *
115  *****************************************************************************/
116 
117 #define __NSACCESS_C__
118 
119 #include "acpi.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.
206          * If entry in PreDefinedNames[] specifies an
207          * initial value, create the initial value.
208          */
209         if (InitVal->Val)
210         {
211             Status = AcpiOsPredefinedOverride (InitVal, &Val);
212             if (ACPI_FAILURE (Status))
213             {
214                 ACPI_ERROR ((AE_INFO,
215                     "Could not override predefined %s",
216                     InitVal->Name));
217             }
218 
219             if (!Val)
220             {
221                 Val = InitVal->Val;
222             }
223 
224             /*
225              * Entry requests an initial value, allocate a
226              * descriptor for it.
227              */
228             ObjDesc = AcpiUtCreateInternalObject (InitVal->Type);
229             if (!ObjDesc)
230             {
231                 Status = AE_NO_MEMORY;
232                 goto UnlockAndExit;
233             }
234 
235             /*
236              * Convert value string from table entry to
237              * internal representation. Only types actually
238              * used for initial values are implemented here.
239              */
240             switch (InitVal->Type)
241             {
242             case ACPI_TYPE_METHOD:
243                 ObjDesc->Method.ParamCount = (UINT8) ACPI_TO_INTEGER (Val);
244                 ObjDesc->Common.Flags |= AOPOBJ_DATA_VALID;
245 
246 #if defined (ACPI_ASL_COMPILER)
247 
248                 /* Save the parameter count for the iASL compiler */
249 
250                 NewNode->Value = ObjDesc->Method.ParamCount;
251 #else
252                 /* Mark this as a very SPECIAL method */
253 
254                 ObjDesc->Method.MethodFlags = AML_METHOD_INTERNAL_ONLY;
255 
256 #ifndef ACPI_DUMP_APP
257                 ObjDesc->Method.Implementation = AcpiUtOsiImplementation;
258 #endif
259 #endif
260                 break;
261 
262             case ACPI_TYPE_INTEGER:
263 
264                 ObjDesc->Integer.Value = ACPI_TO_INTEGER (Val);
265                 break;
266 
267 
268             case ACPI_TYPE_STRING:
269 
270                 /*
271                  * Build an object around the static string
272                  */
273                 ObjDesc->String.Length = (UINT32) ACPI_STRLEN (Val);
274                 ObjDesc->String.Pointer = Val;
275                 ObjDesc->Common.Flags |= AOPOBJ_STATIC_POINTER;
276                 break;
277 
278 
279             case ACPI_TYPE_MUTEX:
280 
281                 ObjDesc->Mutex.Node = NewNode;
282                 ObjDesc->Mutex.SyncLevel = (UINT8) (ACPI_TO_INTEGER (Val) - 1);
283 
284                 /* Create a mutex */
285 
286                 Status = AcpiOsCreateMutex (&ObjDesc->Mutex.OsMutex);
287                 if (ACPI_FAILURE (Status))
288                 {
289                     AcpiUtRemoveReference (ObjDesc);
290                     goto UnlockAndExit;
291                 }
292 
293                 /* Special case for ACPI Global Lock */
294 
295                 if (ACPI_STRCMP (InitVal->Name, "_GL_") == 0)
296                 {
297                     AcpiGbl_GlobalLockMutex = ObjDesc;
298 
299                     /* Create additional counting semaphore for global lock */
300 
301                     Status = AcpiOsCreateSemaphore (
302                                 1, 0, &AcpiGbl_GlobalLockSemaphore);
303                     if (ACPI_FAILURE (Status))
304                     {
305                         AcpiUtRemoveReference (ObjDesc);
306                         goto UnlockAndExit;
307                     }
308                 }
309                 break;
310 
311 
312             default:
313 
314                 ACPI_ERROR ((AE_INFO, "Unsupported initial type value %X",
315                     InitVal->Type));
316                 AcpiUtRemoveReference (ObjDesc);
317                 ObjDesc = NULL;
318                 continue;
319             }
320 
321             /* Store pointer to value descriptor in the Node */
322 
323             Status = AcpiNsAttachObject (NewNode, ObjDesc,
324                         ACPI_GET_OBJECT_TYPE (ObjDesc));
325 
326             /* Remove local reference to the object */
327 
328             AcpiUtRemoveReference (ObjDesc);
329         }
330     }
331 
332 
333 UnlockAndExit:
334     (void) AcpiUtReleaseMutex (ACPI_MTX_NAMESPACE);
335 
336     /* Save a handle to "_GPE", it is always present */
337 
338     if (ACPI_SUCCESS (Status))
339     {
340         Status = AcpiNsGetNode (NULL, "\\_GPE", ACPI_NS_NO_UPSEARCH,
341                     &AcpiGbl_FadtGpeDevice);
342     }
343 
344     return_ACPI_STATUS (Status);
345 }
346 
347 
348 /*******************************************************************************
349  *
350  * FUNCTION:    AcpiNsLookup
351  *
352  * PARAMETERS:  ScopeInfo       - Current scope info block
353  *              Pathname        - Search pathname, in internal format
354  *                                (as represented in the AML stream)
355  *              Type            - Type associated with name
356  *              InterpreterMode - IMODE_LOAD_PASS2 => add name if not found
357  *              Flags           - Flags describing the search restrictions
358  *              WalkState       - Current state of the walk
359  *              ReturnNode      - Where the Node is placed (if found
360  *                                or created successfully)
361  *
362  * RETURN:      Status
363  *
364  * DESCRIPTION: Find or enter the passed name in the name space.
365  *              Log an error if name not found in Exec mode.
366  *
367  * MUTEX:       Assumes namespace is locked.
368  *
369  ******************************************************************************/
370 
371 ACPI_STATUS
372 AcpiNsLookup (
373     ACPI_GENERIC_STATE      *ScopeInfo,
374     char                    *Pathname,
375     ACPI_OBJECT_TYPE        Type,
376     ACPI_INTERPRETER_MODE   InterpreterMode,
377     UINT32                  Flags,
378     ACPI_WALK_STATE         *WalkState,
379     ACPI_NAMESPACE_NODE     **ReturnNode)
380 {
381     ACPI_STATUS             Status;
382     char                    *Path = Pathname;
383     ACPI_NAMESPACE_NODE     *PrefixNode;
384     ACPI_NAMESPACE_NODE     *CurrentNode = NULL;
385     ACPI_NAMESPACE_NODE     *ThisNode = NULL;
386     UINT32                  NumSegments;
387     UINT32                  NumCarats;
388     ACPI_NAME               SimpleName;
389     ACPI_OBJECT_TYPE        TypeToCheckFor;
390     ACPI_OBJECT_TYPE        ThisSearchType;
391     UINT32                  SearchParentFlag = ACPI_NS_SEARCH_PARENT;
392     UINT32                  LocalFlags;
393 
394 
395     ACPI_FUNCTION_TRACE (NsLookup);
396 
397 
398     if (!ReturnNode)
399     {
400         return_ACPI_STATUS (AE_BAD_PARAMETER);
401     }
402 
403     LocalFlags = Flags & ~(ACPI_NS_ERROR_IF_FOUND | ACPI_NS_SEARCH_PARENT);
404     *ReturnNode = ACPI_ENTRY_NOT_FOUND;
405     AcpiGbl_NsLookupCount++;
406 
407     if (!AcpiGbl_RootNode)
408     {
409         return_ACPI_STATUS (AE_NO_NAMESPACE);
410     }
411 
412     /*
413      * Get the prefix scope.
414      * A null scope means use the root scope
415      */
416     if ((!ScopeInfo) ||
417         (!ScopeInfo->Scope.Node))
418     {
419         ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
420             "Null scope prefix, using root node (%p)\n",
421             AcpiGbl_RootNode));
422 
423         PrefixNode = AcpiGbl_RootNode;
424     }
425     else
426     {
427         PrefixNode = ScopeInfo->Scope.Node;
428         if (ACPI_GET_DESCRIPTOR_TYPE (PrefixNode) != ACPI_DESC_TYPE_NAMED)
429         {
430             ACPI_ERROR ((AE_INFO, "%p is not a namespace node [%s]",
431                 PrefixNode, AcpiUtGetDescriptorName (PrefixNode)));
432             return_ACPI_STATUS (AE_AML_INTERNAL);
433         }
434 
435         if (!(Flags & ACPI_NS_PREFIX_IS_SCOPE))
436         {
437             /*
438              * This node might not be a actual "scope" node (such as a
439              * Device/Method, etc.)  It could be a Package or other object node.
440              * Backup up the tree to find the containing scope node.
441              */
442             while (!AcpiNsOpensScope (PrefixNode->Type) &&
443                     PrefixNode->Type != ACPI_TYPE_ANY)
444             {
445                 PrefixNode = AcpiNsGetParentNode (PrefixNode);
446             }
447         }
448     }
449 
450     /* Save type   TBD: may be no longer necessary */
451 
452     TypeToCheckFor = Type;
453 
454     /*
455      * Begin examination of the actual pathname
456      */
457     if (!Pathname)
458     {
459         /* A Null NamePath is allowed and refers to the root */
460 
461         NumSegments = 0;
462         ThisNode = AcpiGbl_RootNode;
463         Path = "";
464 
465         ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
466             "Null Pathname (Zero segments), Flags=%X\n", Flags));
467     }
468     else
469     {
470         /*
471          * Name pointer is valid (and must be in internal name format)
472          *
473          * Check for scope prefixes:
474          *
475          * As represented in the AML stream, a namepath consists of an
476          * optional scope prefix followed by a name segment part.
477          *
478          * If present, the scope prefix is either a Root Prefix (in
479          * which case the name is fully qualified), or one or more
480          * Parent Prefixes (in which case the name's scope is relative
481          * to the current scope).
482          */
483         if (*Path == (UINT8) AML_ROOT_PREFIX)
484         {
485             /* Pathname is fully qualified, start from the root */
486 
487             ThisNode = AcpiGbl_RootNode;
488             SearchParentFlag = ACPI_NS_NO_UPSEARCH;
489 
490             /* Point to name segment part */
491 
492             Path++;
493 
494             ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
495                 "Path is absolute from root [%p]\n", ThisNode));
496         }
497         else
498         {
499             /* Pathname is relative to current scope, start there */
500 
501             ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
502                 "Searching relative to prefix scope [%4.4s] (%p)\n",
503                 AcpiUtGetNodeName (PrefixNode), PrefixNode));
504 
505             /*
506              * Handle multiple Parent Prefixes (carat) by just getting
507              * the parent node for each prefix instance.
508              */
509             ThisNode = PrefixNode;
510             NumCarats = 0;
511             while (*Path == (UINT8) AML_PARENT_PREFIX)
512             {
513                 /* Name is fully qualified, no search rules apply */
514 
515                 SearchParentFlag = ACPI_NS_NO_UPSEARCH;
516                 /*
517                  * Point past this prefix to the name segment
518                  * part or the next Parent Prefix
519                  */
520                 Path++;
521 
522                 /* Backup to the parent node */
523 
524                 NumCarats++;
525                 ThisNode = AcpiNsGetParentNode (ThisNode);
526                 if (!ThisNode)
527                 {
528                     /* Current scope has no parent scope */
529 
530                     ACPI_ERROR ((AE_INFO,
531                         "ACPI path has too many parent prefixes (^) - reached beyond root node"));
532                     return_ACPI_STATUS (AE_NOT_FOUND);
533                 }
534             }
535 
536             if (SearchParentFlag == ACPI_NS_NO_UPSEARCH)
537             {
538                 ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
539                     "Search scope is [%4.4s], path has %d carat(s)\n",
540                     AcpiUtGetNodeName (ThisNode), NumCarats));
541             }
542         }
543 
544         /*
545          * Determine the number of ACPI name segments in this pathname.
546          *
547          * The segment part consists of either:
548          *  - A Null name segment (0)
549          *  - A DualNamePrefix followed by two 4-byte name segments
550          *  - A MultiNamePrefix followed by a byte indicating the
551          *      number of segments and the segments themselves.
552          *  - A single 4-byte name segment
553          *
554          * Examine the name prefix opcode, if any, to determine the number of
555          * segments.
556          */
557         switch (*Path)
558         {
559         case 0:
560             /*
561              * Null name after a root or parent prefixes. We already
562              * have the correct target node and there are no name segments.
563              */
564             NumSegments  = 0;
565             Type = ThisNode->Type;
566 
567             ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
568                 "Prefix-only Pathname (Zero name segments), Flags=%X\n",
569                 Flags));
570             break;
571 
572         case AML_DUAL_NAME_PREFIX:
573 
574             /* More than one NameSeg, search rules do not apply */
575 
576             SearchParentFlag = ACPI_NS_NO_UPSEARCH;
577 
578             /* Two segments, point to first name segment */
579 
580             NumSegments = 2;
581             Path++;
582 
583             ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
584                 "Dual Pathname (2 segments, Flags=%X)\n", Flags));
585             break;
586 
587         case AML_MULTI_NAME_PREFIX_OP:
588 
589             /* More than one NameSeg, search rules do not apply */
590 
591             SearchParentFlag = ACPI_NS_NO_UPSEARCH;
592 
593             /* Extract segment count, point to first name segment */
594 
595             Path++;
596             NumSegments = (UINT32) (UINT8) *Path;
597             Path++;
598 
599             ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
600                 "Multi Pathname (%d Segments, Flags=%X)\n",
601                 NumSegments, Flags));
602             break;
603 
604         default:
605             /*
606              * Not a Null name, no Dual or Multi prefix, hence there is
607              * only one name segment and Pathname is already pointing to it.
608              */
609             NumSegments = 1;
610 
611             ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
612                 "Simple Pathname (1 segment, Flags=%X)\n", Flags));
613             break;
614         }
615 
616         ACPI_DEBUG_EXEC (AcpiNsPrintPathname (NumSegments, Path));
617     }
618 
619 
620     /*
621      * Search namespace for each segment of the name.  Loop through and
622      * verify (or add to the namespace) each name segment.
623      *
624      * The object type is significant only at the last name
625      * segment.  (We don't care about the types along the path, only
626      * the type of the final target object.)
627      */
628     ThisSearchType = ACPI_TYPE_ANY;
629     CurrentNode = ThisNode;
630     while (NumSegments && CurrentNode)
631     {
632         NumSegments--;
633         if (!NumSegments)
634         {
635             /*
636              * This is the last segment, enable typechecking
637              */
638             ThisSearchType = Type;
639 
640             /*
641              * Only allow automatic parent search (search rules) if the caller
642              * requested it AND we have a single, non-fully-qualified NameSeg
643              */
644             if ((SearchParentFlag != ACPI_NS_NO_UPSEARCH) &&
645                 (Flags & ACPI_NS_SEARCH_PARENT))
646             {
647                 LocalFlags |= ACPI_NS_SEARCH_PARENT;
648             }
649 
650             /* Set error flag according to caller */
651 
652             if (Flags & ACPI_NS_ERROR_IF_FOUND)
653             {
654                 LocalFlags |= ACPI_NS_ERROR_IF_FOUND;
655             }
656         }
657 
658         /* Extract one ACPI name from the front of the pathname */
659 
660         ACPI_MOVE_32_TO_32 (&SimpleName, Path);
661 
662         /* Try to find the single (4 character) ACPI name */
663 
664         Status = AcpiNsSearchAndEnter (SimpleName, WalkState, CurrentNode,
665                     InterpreterMode, ThisSearchType, LocalFlags, &ThisNode);
666         if (ACPI_FAILURE (Status))
667         {
668             if (Status == AE_NOT_FOUND)
669             {
670                 /* Name not found in ACPI namespace */
671 
672                 ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
673                     "Name [%4.4s] not found in scope [%4.4s] %p\n",
674                     (char *) &SimpleName, (char *) &CurrentNode->Name,
675                     CurrentNode));
676             }
677 
678             *ReturnNode = ThisNode;
679             return_ACPI_STATUS (Status);
680         }
681 
682         /* More segments to follow? */
683 
684         if (NumSegments > 0)
685         {
686             /*
687              * If we have an alias to an object that opens a scope (such as a
688              * device or processor), we need to dereference the alias here so that
689              * we can access any children of the original node (via the remaining
690              * segments).
691              */
692             if (ThisNode->Type == ACPI_TYPE_LOCAL_ALIAS)
693             {
694                 if (AcpiNsOpensScope (((ACPI_NAMESPACE_NODE *) 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 type
737              * 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     /*
752      * Always check if we need to open a new scope
753      */
754     if (!(Flags & ACPI_NS_DONT_OPEN_SCOPE) && (WalkState))
755     {
756         /*
757          * If entry is a type which opens a scope, push the new scope on the
758          * scope stack.
759          */
760         if (AcpiNsOpensScope (Type))
761         {
762             Status = AcpiDsScopeStackPush (ThisNode, Type, WalkState);
763             if (ACPI_FAILURE (Status))
764             {
765                 return_ACPI_STATUS (Status);
766             }
767         }
768     }
769 
770     *ReturnNode = ThisNode;
771     return_ACPI_STATUS (AE_OK);
772 }
773 
774