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  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 - 2011, 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.InfoFlags = ACPI_METHOD_INTERNAL_ONLY;
  254.                 ObjDesc->Method.Dispatch.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 0x%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 = PrefixNode->Parent;
  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 = ThisNode->Parent;
  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 %u 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 (%u 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.  
  773.