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dsfield.c revision 1.1.1.2
      1 /******************************************************************************
      2  *
      3  * Module Name: dsfield - Dispatcher field routines
      4  *
      5  *****************************************************************************/
      6 
      7 /*
      8  * Copyright (C) 2000 - 2011, 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 #define __DSFIELD_C__
     45 
     46 #include "acpi.h"
     47 #include "accommon.h"
     48 #include "amlcode.h"
     49 #include "acdispat.h"
     50 #include "acinterp.h"
     51 #include "acnamesp.h"
     52 #include "acparser.h"
     53 
     54 
     55 #define _COMPONENT          ACPI_DISPATCHER
     56         ACPI_MODULE_NAME    ("dsfield")
     57 
     58 /* Local prototypes */
     59 
     60 static ACPI_STATUS
     61 AcpiDsGetFieldNames (
     62     ACPI_CREATE_FIELD_INFO  *Info,
     63     ACPI_WALK_STATE         *WalkState,
     64     ACPI_PARSE_OBJECT       *Arg);
     65 
     66 
     67 /*******************************************************************************
     68  *
     69  * FUNCTION:    AcpiDsCreateBufferField
     70  *
     71  * PARAMETERS:  Op                  - Current parse op (CreateXXField)
     72  *              WalkState           - Current state
     73  *
     74  * RETURN:      Status
     75  *
     76  * DESCRIPTION: Execute the CreateField operators:
     77  *              CreateBitFieldOp,
     78  *              CreateByteFieldOp,
     79  *              CreateWordFieldOp,
     80  *              CreateDWordFieldOp,
     81  *              CreateQWordFieldOp,
     82  *              CreateFieldOp       (all of which define a field in a buffer)
     83  *
     84  ******************************************************************************/
     85 
     86 ACPI_STATUS
     87 AcpiDsCreateBufferField (
     88     ACPI_PARSE_OBJECT       *Op,
     89     ACPI_WALK_STATE         *WalkState)
     90 {
     91     ACPI_PARSE_OBJECT       *Arg;
     92     ACPI_NAMESPACE_NODE     *Node;
     93     ACPI_STATUS             Status;
     94     ACPI_OPERAND_OBJECT     *ObjDesc;
     95     ACPI_OPERAND_OBJECT     *SecondDesc = NULL;
     96     UINT32                  Flags;
     97 
     98 
     99     ACPI_FUNCTION_TRACE (DsCreateBufferField);
    100 
    101 
    102     /*
    103      * Get the NameString argument (name of the new BufferField)
    104      */
    105     if (Op->Common.AmlOpcode == AML_CREATE_FIELD_OP)
    106     {
    107         /* For CreateField, name is the 4th argument */
    108 
    109         Arg = AcpiPsGetArg (Op, 3);
    110     }
    111     else
    112     {
    113         /* For all other CreateXXXField operators, name is the 3rd argument */
    114 
    115         Arg = AcpiPsGetArg (Op, 2);
    116     }
    117 
    118     if (!Arg)
    119     {
    120         return_ACPI_STATUS (AE_AML_NO_OPERAND);
    121     }
    122 
    123     if (WalkState->DeferredNode)
    124     {
    125         Node = WalkState->DeferredNode;
    126         Status = AE_OK;
    127     }
    128     else
    129     {
    130         /* Execute flag should always be set when this function is entered */
    131 
    132         if (!(WalkState->ParseFlags & ACPI_PARSE_EXECUTE))
    133         {
    134             return_ACPI_STATUS (AE_AML_INTERNAL);
    135         }
    136 
    137         /* Creating new namespace node, should not already exist */
    138 
    139         Flags = ACPI_NS_NO_UPSEARCH | ACPI_NS_DONT_OPEN_SCOPE |
    140                 ACPI_NS_ERROR_IF_FOUND;
    141 
    142         /*
    143          * Mark node temporary if we are executing a normal control
    144          * method. (Don't mark if this is a module-level code method)
    145          */
    146         if (WalkState->MethodNode &&
    147             !(WalkState->ParseFlags & ACPI_PARSE_MODULE_LEVEL))
    148         {
    149             Flags |= ACPI_NS_TEMPORARY;
    150         }
    151 
    152         /* Enter the NameString into the namespace */
    153 
    154         Status = AcpiNsLookup (WalkState->ScopeInfo, Arg->Common.Value.String,
    155                     ACPI_TYPE_ANY, ACPI_IMODE_LOAD_PASS1,
    156                     Flags, WalkState, &Node);
    157         if (ACPI_FAILURE (Status))
    158         {
    159             ACPI_ERROR_NAMESPACE (Arg->Common.Value.String, Status);
    160             return_ACPI_STATUS (Status);
    161         }
    162     }
    163 
    164     /*
    165      * We could put the returned object (Node) on the object stack for later,
    166      * but for now, we will put it in the "op" object that the parser uses,
    167      * so we can get it again at the end of this scope.
    168      */
    169     Op->Common.Node = Node;
    170 
    171     /*
    172      * If there is no object attached to the node, this node was just created
    173      * and we need to create the field object. Otherwise, this was a lookup
    174      * of an existing node and we don't want to create the field object again.
    175      */
    176     ObjDesc = AcpiNsGetAttachedObject (Node);
    177     if (ObjDesc)
    178     {
    179         return_ACPI_STATUS (AE_OK);
    180     }
    181 
    182     /*
    183      * The Field definition is not fully parsed at this time.
    184      * (We must save the address of the AML for the buffer and index operands)
    185      */
    186 
    187     /* Create the buffer field object */
    188 
    189     ObjDesc = AcpiUtCreateInternalObject (ACPI_TYPE_BUFFER_FIELD);
    190     if (!ObjDesc)
    191     {
    192         Status = AE_NO_MEMORY;
    193         goto Cleanup;
    194     }
    195 
    196     /*
    197      * Remember location in AML stream of the field unit opcode and operands --
    198      * since the buffer and index operands must be evaluated.
    199      */
    200     SecondDesc                  = ObjDesc->Common.NextObject;
    201     SecondDesc->Extra.AmlStart  = Op->Named.Data;
    202     SecondDesc->Extra.AmlLength = Op->Named.Length;
    203     ObjDesc->BufferField.Node   = Node;
    204 
    205     /* Attach constructed field descriptors to parent node */
    206 
    207     Status = AcpiNsAttachObject (Node, ObjDesc, ACPI_TYPE_BUFFER_FIELD);
    208     if (ACPI_FAILURE (Status))
    209     {
    210         goto Cleanup;
    211     }
    212 
    213 
    214 Cleanup:
    215 
    216     /* Remove local reference to the object */
    217 
    218     AcpiUtRemoveReference (ObjDesc);
    219     return_ACPI_STATUS (Status);
    220 }
    221 
    222 
    223 /*******************************************************************************
    224  *
    225  * FUNCTION:    AcpiDsGetFieldNames
    226  *
    227  * PARAMETERS:  Info            - CreateField info structure
    228  *  `           WalkState       - Current method state
    229  *              Arg             - First parser arg for the field name list
    230  *
    231  * RETURN:      Status
    232  *
    233  * DESCRIPTION: Process all named fields in a field declaration.  Names are
    234  *              entered into the namespace.
    235  *
    236  ******************************************************************************/
    237 
    238 static ACPI_STATUS
    239 AcpiDsGetFieldNames (
    240     ACPI_CREATE_FIELD_INFO  *Info,
    241     ACPI_WALK_STATE         *WalkState,
    242     ACPI_PARSE_OBJECT       *Arg)
    243 {
    244     ACPI_STATUS             Status;
    245     UINT64                  Position;
    246 
    247 
    248     ACPI_FUNCTION_TRACE_PTR (DsGetFieldNames, Info);
    249 
    250 
    251     /* First field starts at bit zero */
    252 
    253     Info->FieldBitPosition = 0;
    254 
    255     /* Process all elements in the field list (of parse nodes) */
    256 
    257     while (Arg)
    258     {
    259         /*
    260          * Three types of field elements are handled:
    261          * 1) Offset - specifies a bit offset
    262          * 2) AccessAs - changes the access mode
    263          * 3) Name - Enters a new named field into the namespace
    264          */
    265         switch (Arg->Common.AmlOpcode)
    266         {
    267         case AML_INT_RESERVEDFIELD_OP:
    268 
    269             Position = (UINT64) Info->FieldBitPosition
    270                         + (UINT64) Arg->Common.Value.Size;
    271 
    272             if (Position > ACPI_UINT32_MAX)
    273             {
    274                 ACPI_ERROR ((AE_INFO,
    275                     "Bit offset within field too large (> 0xFFFFFFFF)"));
    276                 return_ACPI_STATUS (AE_SUPPORT);
    277             }
    278 
    279             Info->FieldBitPosition = (UINT32) Position;
    280             break;
    281 
    282 
    283         case AML_INT_ACCESSFIELD_OP:
    284 
    285             /*
    286              * Get a new AccessType and AccessAttribute -- to be used for all
    287              * field units that follow, until field end or another AccessAs
    288              * keyword.
    289              *
    290              * In FieldFlags, preserve the flag bits other than the
    291              * ACCESS_TYPE bits
    292              */
    293             Info->FieldFlags = (UINT8)
    294                 ((Info->FieldFlags & ~(AML_FIELD_ACCESS_TYPE_MASK)) |
    295                 ((UINT8) ((UINT32) Arg->Common.Value.Integer >> 8)));
    296 
    297             Info->Attribute = (UINT8) (Arg->Common.Value.Integer);
    298             break;
    299 
    300 
    301         case AML_INT_NAMEDFIELD_OP:
    302 
    303             /* Lookup the name, it should already exist */
    304 
    305             Status = AcpiNsLookup (WalkState->ScopeInfo,
    306                         (char *) &Arg->Named.Name, Info->FieldType,
    307                         ACPI_IMODE_EXECUTE, ACPI_NS_DONT_OPEN_SCOPE,
    308                         WalkState, &Info->FieldNode);
    309             if (ACPI_FAILURE (Status))
    310             {
    311                 ACPI_ERROR_NAMESPACE ((char *) &Arg->Named.Name, Status);
    312                 return_ACPI_STATUS (Status);
    313             }
    314             else
    315             {
    316                 Arg->Common.Node = Info->FieldNode;
    317                 Info->FieldBitLength = Arg->Common.Value.Size;
    318 
    319                 /*
    320                  * If there is no object attached to the node, this node was
    321                  * just created and we need to create the field object.
    322                  * Otherwise, this was a lookup of an existing node and we
    323                  * don't want to create the field object again.
    324                  */
    325                 if (!AcpiNsGetAttachedObject (Info->FieldNode))
    326                 {
    327                     Status = AcpiExPrepFieldValue (Info);
    328                     if (ACPI_FAILURE (Status))
    329                     {
    330                         return_ACPI_STATUS (Status);
    331                     }
    332                 }
    333             }
    334 
    335             /* Keep track of bit position for the next field */
    336 
    337             Position = (UINT64) Info->FieldBitPosition
    338                         + (UINT64) Arg->Common.Value.Size;
    339 
    340             if (Position > ACPI_UINT32_MAX)
    341             {
    342                 ACPI_ERROR ((AE_INFO,
    343                     "Field [%4.4s] bit offset too large (> 0xFFFFFFFF)",
    344                     ACPI_CAST_PTR (char, &Info->FieldNode->Name)));
    345                 return_ACPI_STATUS (AE_SUPPORT);
    346             }
    347 
    348             Info->FieldBitPosition += Info->FieldBitLength;
    349             break;
    350 
    351 
    352         default:
    353 
    354             ACPI_ERROR ((AE_INFO,
    355                 "Invalid opcode in field list: 0x%X", Arg->Common.AmlOpcode));
    356             return_ACPI_STATUS (AE_AML_BAD_OPCODE);
    357         }
    358 
    359         Arg = Arg->Common.Next;
    360     }
    361 
    362     return_ACPI_STATUS (AE_OK);
    363 }
    364 
    365 
    366 /*******************************************************************************
    367  *
    368  * FUNCTION:    AcpiDsCreateField
    369  *
    370  * PARAMETERS:  Op              - Op containing the Field definition and args
    371  *              RegionNode      - Object for the containing Operation Region
    372  *  `           WalkState       - Current method state
    373  *
    374  * RETURN:      Status
    375  *
    376  * DESCRIPTION: Create a new field in the specified operation region
    377  *
    378  ******************************************************************************/
    379 
    380 ACPI_STATUS
    381 AcpiDsCreateField (
    382     ACPI_PARSE_OBJECT       *Op,
    383     ACPI_NAMESPACE_NODE     *RegionNode,
    384     ACPI_WALK_STATE         *WalkState)
    385 {
    386     ACPI_STATUS             Status;
    387     ACPI_PARSE_OBJECT       *Arg;
    388     ACPI_CREATE_FIELD_INFO  Info;
    389 
    390 
    391     ACPI_FUNCTION_TRACE_PTR (DsCreateField, Op);
    392 
    393 
    394     /* First arg is the name of the parent OpRegion (must already exist) */
    395 
    396     Arg = Op->Common.Value.Arg;
    397     if (!RegionNode)
    398     {
    399         Status = AcpiNsLookup (WalkState->ScopeInfo, Arg->Common.Value.Name,
    400                         ACPI_TYPE_REGION, ACPI_IMODE_EXECUTE,
    401                         ACPI_NS_SEARCH_PARENT, WalkState, &RegionNode);
    402         if (ACPI_FAILURE (Status))
    403         {
    404             ACPI_ERROR_NAMESPACE (Arg->Common.Value.Name, Status);
    405             return_ACPI_STATUS (Status);
    406         }
    407     }
    408 
    409     /* Second arg is the field flags */
    410 
    411     Arg = Arg->Common.Next;
    412     Info.FieldFlags = (UINT8) Arg->Common.Value.Integer;
    413     Info.Attribute = 0;
    414 
    415     /* Each remaining arg is a Named Field */
    416 
    417     Info.FieldType = ACPI_TYPE_LOCAL_REGION_FIELD;
    418     Info.RegionNode = RegionNode;
    419 
    420     Status = AcpiDsGetFieldNames (&Info, WalkState, Arg->Common.Next);
    421 
    422     return_ACPI_STATUS (Status);
    423 }
    424 
    425 
    426 /*******************************************************************************
    427  *
    428  * FUNCTION:    AcpiDsInitFieldObjects
    429  *
    430  * PARAMETERS:  Op              - Op containing the Field definition and args
    431  *  `           WalkState       - Current method state
    432  *
    433  * RETURN:      Status
    434  *
    435  * DESCRIPTION: For each "Field Unit" name in the argument list that is
    436  *              part of the field declaration, enter the name into the
    437  *              namespace.
    438  *
    439  ******************************************************************************/
    440 
    441 ACPI_STATUS
    442 AcpiDsInitFieldObjects (
    443     ACPI_PARSE_OBJECT       *Op,
    444     ACPI_WALK_STATE         *WalkState)
    445 {
    446     ACPI_STATUS             Status;
    447     ACPI_PARSE_OBJECT       *Arg = NULL;
    448     ACPI_NAMESPACE_NODE     *Node;
    449     UINT8                   Type = 0;
    450     UINT32                  Flags;
    451 
    452 
    453     ACPI_FUNCTION_TRACE_PTR (DsInitFieldObjects, Op);
    454 
    455 
    456     /* Execute flag should always be set when this function is entered */
    457 
    458     if (!(WalkState->ParseFlags & ACPI_PARSE_EXECUTE))
    459     {
    460         if (WalkState->ParseFlags & ACPI_PARSE_DEFERRED_OP)
    461         {
    462             /* BankField Op is deferred, just return OK */
    463 
    464             return_ACPI_STATUS (AE_OK);
    465         }
    466 
    467         return_ACPI_STATUS (AE_AML_INTERNAL);
    468     }
    469 
    470     /*
    471      * Get the FieldList argument for this opcode. This is the start of the
    472      * list of field elements.
    473      */
    474     switch (WalkState->Opcode)
    475     {
    476     case AML_FIELD_OP:
    477         Arg = AcpiPsGetArg (Op, 2);
    478         Type = ACPI_TYPE_LOCAL_REGION_FIELD;
    479         break;
    480 
    481     case AML_BANK_FIELD_OP:
    482         Arg = AcpiPsGetArg (Op, 4);
    483         Type = ACPI_TYPE_LOCAL_BANK_FIELD;
    484         break;
    485 
    486     case AML_INDEX_FIELD_OP:
    487         Arg = AcpiPsGetArg (Op, 3);
    488         Type = ACPI_TYPE_LOCAL_INDEX_FIELD;
    489         break;
    490 
    491     default:
    492         return_ACPI_STATUS (AE_BAD_PARAMETER);
    493     }
    494 
    495     /* Creating new namespace node(s), should not already exist */
    496 
    497     Flags = ACPI_NS_NO_UPSEARCH | ACPI_NS_DONT_OPEN_SCOPE |
    498             ACPI_NS_ERROR_IF_FOUND;
    499 
    500     /*
    501      * Mark node(s) temporary if we are executing a normal control
    502      * method. (Don't mark if this is a module-level code method)
    503      */
    504     if (WalkState->MethodNode &&
    505         !(WalkState->ParseFlags & ACPI_PARSE_MODULE_LEVEL))
    506     {
    507         Flags |= ACPI_NS_TEMPORARY;
    508     }
    509 
    510     /*
    511      * Walk the list of entries in the FieldList
    512      * Note: FieldList can be of zero length. In this case, Arg will be NULL.
    513      */
    514     while (Arg)
    515     {
    516         /*
    517          * Ignore OFFSET and ACCESSAS terms here; we are only interested in the
    518          * field names in order to enter them into the namespace.
    519          */
    520         if (Arg->Common.AmlOpcode == AML_INT_NAMEDFIELD_OP)
    521         {
    522             Status = AcpiNsLookup (WalkState->ScopeInfo,
    523                         (char *) &Arg->Named.Name, Type, ACPI_IMODE_LOAD_PASS1,
    524                         Flags, WalkState, &Node);
    525             if (ACPI_FAILURE (Status))
    526             {
    527                 ACPI_ERROR_NAMESPACE ((char *) &Arg->Named.Name, Status);
    528                 if (Status != AE_ALREADY_EXISTS)
    529                 {
    530                     return_ACPI_STATUS (Status);
    531                 }
    532 
    533                 /* Name already exists, just ignore this error */
    534 
    535                 Status = AE_OK;
    536             }
    537 
    538             Arg->Common.Node = Node;
    539         }
    540 
    541         /* Get the next field element in the list */
    542 
    543         Arg = Arg->Common.Next;
    544     }
    545 
    546     return_ACPI_STATUS (AE_OK);
    547 }
    548 
    549 
    550 /*******************************************************************************
    551  *
    552  * FUNCTION:    AcpiDsCreateBankField
    553  *
    554  * PARAMETERS:  Op              - Op containing the Field definition and args
    555  *              RegionNode      - Object for the containing Operation Region
    556  *              WalkState       - Current method state
    557  *
    558  * RETURN:      Status
    559  *
    560  * DESCRIPTION: Create a new bank field in the specified operation region
    561  *
    562  ******************************************************************************/
    563 
    564 ACPI_STATUS
    565 AcpiDsCreateBankField (
    566     ACPI_PARSE_OBJECT       *Op,
    567     ACPI_NAMESPACE_NODE     *RegionNode,
    568     ACPI_WALK_STATE         *WalkState)
    569 {
    570     ACPI_STATUS             Status;
    571     ACPI_PARSE_OBJECT       *Arg;
    572     ACPI_CREATE_FIELD_INFO  Info;
    573 
    574 
    575     ACPI_FUNCTION_TRACE_PTR (DsCreateBankField, Op);
    576 
    577 
    578     /* First arg is the name of the parent OpRegion (must already exist) */
    579 
    580     Arg = Op->Common.Value.Arg;
    581     if (!RegionNode)
    582     {
    583         Status = AcpiNsLookup (WalkState->ScopeInfo, Arg->Common.Value.Name,
    584                         ACPI_TYPE_REGION, ACPI_IMODE_EXECUTE,
    585                         ACPI_NS_SEARCH_PARENT, WalkState, &RegionNode);
    586         if (ACPI_FAILURE (Status))
    587         {
    588             ACPI_ERROR_NAMESPACE (Arg->Common.Value.Name, Status);
    589             return_ACPI_STATUS (Status);
    590         }
    591     }
    592 
    593     /* Second arg is the Bank Register (Field) (must already exist) */
    594 
    595     Arg = Arg->Common.Next;
    596     Status = AcpiNsLookup (WalkState->ScopeInfo, Arg->Common.Value.String,
    597                     ACPI_TYPE_ANY, ACPI_IMODE_EXECUTE,
    598                     ACPI_NS_SEARCH_PARENT, WalkState, &Info.RegisterNode);
    599     if (ACPI_FAILURE (Status))
    600     {
    601         ACPI_ERROR_NAMESPACE (Arg->Common.Value.String, Status);
    602         return_ACPI_STATUS (Status);
    603     }
    604 
    605     /*
    606      * Third arg is the BankValue
    607      * This arg is a TermArg, not a constant
    608      * It will be evaluated later, by AcpiDsEvalBankFieldOperands
    609      */
    610     Arg = Arg->Common.Next;
    611 
    612     /* Fourth arg is the field flags */
    613 
    614     Arg = Arg->Common.Next;
    615     Info.FieldFlags = (UINT8) Arg->Common.Value.Integer;
    616 
    617     /* Each remaining arg is a Named Field */
    618 
    619     Info.FieldType = ACPI_TYPE_LOCAL_BANK_FIELD;
    620     Info.RegionNode = RegionNode;
    621 
    622     /*
    623      * Use Info.DataRegisterNode to store BankField Op
    624      * It's safe because DataRegisterNode will never be used when create bank field
    625      * We store AmlStart and AmlLength in the BankField Op for late evaluation
    626      * Used in AcpiExPrepFieldValue(Info)
    627      *
    628      * TBD: Or, should we add a field in ACPI_CREATE_FIELD_INFO, like "void *ParentOp"?
    629      */
    630     Info.DataRegisterNode = (ACPI_NAMESPACE_NODE*) Op;
    631 
    632     Status = AcpiDsGetFieldNames (&Info, WalkState, Arg->Common.Next);
    633     return_ACPI_STATUS (Status);
    634 }
    635 
    636 
    637 /*******************************************************************************
    638  *
    639  * FUNCTION:    AcpiDsCreateIndexField
    640  *
    641  * PARAMETERS:  Op              - Op containing the Field definition and args
    642  *              RegionNode      - Object for the containing Operation Region
    643  *  `           WalkState       - Current method state
    644  *
    645  * RETURN:      Status
    646  *
    647  * DESCRIPTION: Create a new index field in the specified operation region
    648  *
    649  ******************************************************************************/
    650 
    651 ACPI_STATUS
    652 AcpiDsCreateIndexField (
    653     ACPI_PARSE_OBJECT       *Op,
    654     ACPI_NAMESPACE_NODE     *RegionNode,
    655     ACPI_WALK_STATE         *WalkState)
    656 {
    657     ACPI_STATUS             Status;
    658     ACPI_PARSE_OBJECT       *Arg;
    659     ACPI_CREATE_FIELD_INFO  Info;
    660 
    661 
    662     ACPI_FUNCTION_TRACE_PTR (DsCreateIndexField, Op);
    663 
    664 
    665     /* First arg is the name of the Index register (must already exist) */
    666 
    667     Arg = Op->Common.Value.Arg;
    668     Status = AcpiNsLookup (WalkState->ScopeInfo, Arg->Common.Value.String,
    669                     ACPI_TYPE_ANY, ACPI_IMODE_EXECUTE,
    670                     ACPI_NS_SEARCH_PARENT, WalkState, &Info.RegisterNode);
    671     if (ACPI_FAILURE (Status))
    672     {
    673         ACPI_ERROR_NAMESPACE (Arg->Common.Value.String, Status);
    674         return_ACPI_STATUS (Status);
    675     }
    676 
    677     /* Second arg is the data register (must already exist) */
    678 
    679     Arg = Arg->Common.Next;
    680     Status = AcpiNsLookup (WalkState->ScopeInfo, Arg->Common.Value.String,
    681                     ACPI_TYPE_ANY, ACPI_IMODE_EXECUTE,
    682                     ACPI_NS_SEARCH_PARENT, WalkState, &Info.DataRegisterNode);
    683     if (ACPI_FAILURE (Status))
    684     {
    685         ACPI_ERROR_NAMESPACE (Arg->Common.Value.String, Status);
    686         return_ACPI_STATUS (Status);
    687     }
    688 
    689     /* Next arg is the field flags */
    690 
    691     Arg = Arg->Common.Next;
    692     Info.FieldFlags = (UINT8) Arg->Common.Value.Integer;
    693 
    694     /* Each remaining arg is a Named Field */
    695 
    696     Info.FieldType = ACPI_TYPE_LOCAL_INDEX_FIELD;
    697     Info.RegionNode = RegionNode;
    698 
    699     Status = AcpiDsGetFieldNames (&Info, WalkState, Arg->Common.Next);
    700 
    701     return_ACPI_STATUS (Status);
    702 }
    703 
    704 
    705