exprep.c revision 151600
1
2/******************************************************************************
3 *
4 * Module Name: exprep - ACPI AML (p-code) execution - field prep utilities
5 *              $Revision: 128 $
6 *
7 *****************************************************************************/
8
9/******************************************************************************
10 *
11 * 1. Copyright Notice
12 *
13 * Some or all of this work - Copyright (c) 1999 - 2004, Intel Corp.
14 * All rights reserved.
15 *
16 * 2. License
17 *
18 * 2.1. This is your license from Intel Corp. under its intellectual property
19 * rights.  You may have additional license terms from the party that provided
20 * you this software, covering your right to use that party's intellectual
21 * property rights.
22 *
23 * 2.2. Intel grants, free of charge, to any person ("Licensee") obtaining a
24 * copy of the source code appearing in this file ("Covered Code") an
25 * irrevocable, perpetual, worldwide license under Intel's copyrights in the
26 * base code distributed originally by Intel ("Original Intel Code") to copy,
27 * make derivatives, distribute, use and display any portion of the Covered
28 * Code in any form, with the right to sublicense such rights; and
29 *
30 * 2.3. Intel grants Licensee a non-exclusive and non-transferable patent
31 * license (with the right to sublicense), under only those claims of Intel
32 * patents that are infringed by the Original Intel Code, to make, use, sell,
33 * offer to sell, and import the Covered Code and derivative works thereof
34 * solely to the minimum extent necessary to exercise the above copyright
35 * license, and in no event shall the patent license extend to any additions
36 * to or modifications of the Original Intel Code.  No other license or right
37 * is granted directly or by implication, estoppel or otherwise;
38 *
39 * The above copyright and patent license is granted only if the following
40 * conditions are met:
41 *
42 * 3. Conditions
43 *
44 * 3.1. Redistribution of Source with Rights to Further Distribute Source.
45 * Redistribution of source code of any substantial portion of the Covered
46 * Code or modification with rights to further distribute source must include
47 * the above Copyright Notice, the above License, this list of Conditions,
48 * and the following Disclaimer and Export Compliance provision.  In addition,
49 * Licensee must cause all Covered Code to which Licensee contributes to
50 * contain a file documenting the changes Licensee made to create that Covered
51 * Code and the date of any change.  Licensee must include in that file the
52 * documentation of any changes made by any predecessor Licensee.  Licensee
53 * must include a prominent statement that the modification is derived,
54 * directly or indirectly, from Original Intel Code.
55 *
56 * 3.2. Redistribution of Source with no Rights to Further Distribute Source.
57 * Redistribution of source code of any substantial portion of the Covered
58 * Code or modification without rights to further distribute source must
59 * include the following Disclaimer and Export Compliance provision in the
60 * documentation and/or other materials provided with distribution.  In
61 * addition, Licensee may not authorize further sublicense of source of any
62 * portion of the Covered Code, and must include terms to the effect that the
63 * license from Licensee to its licensee is limited to the intellectual
64 * property embodied in the software Licensee provides to its licensee, and
65 * not to intellectual property embodied in modifications its licensee may
66 * make.
67 *
68 * 3.3. Redistribution of Executable. Redistribution in executable form of any
69 * substantial portion of the Covered Code or modification must reproduce the
70 * above Copyright Notice, and the following Disclaimer and Export Compliance
71 * provision in the documentation and/or other materials provided with the
72 * distribution.
73 *
74 * 3.4. Intel retains all right, title, and interest in and to the Original
75 * Intel Code.
76 *
77 * 3.5. Neither the name Intel nor any other trademark owned or controlled by
78 * Intel shall be used in advertising or otherwise to promote the sale, use or
79 * other dealings in products derived from or relating to the Covered Code
80 * without prior written authorization from Intel.
81 *
82 * 4. Disclaimer and Export Compliance
83 *
84 * 4.1. INTEL MAKES NO WARRANTY OF ANY KIND REGARDING ANY SOFTWARE PROVIDED
85 * HERE.  ANY SOFTWARE ORIGINATING FROM INTEL OR DERIVED FROM INTEL SOFTWARE
86 * IS PROVIDED "AS IS," AND INTEL WILL NOT PROVIDE ANY SUPPORT,  ASSISTANCE,
87 * INSTALLATION, TRAINING OR OTHER SERVICES.  INTEL WILL NOT PROVIDE ANY
88 * UPDATES, ENHANCEMENTS OR EXTENSIONS.  INTEL SPECIFICALLY DISCLAIMS ANY
89 * IMPLIED WARRANTIES OF MERCHANTABILITY, NONINFRINGEMENT AND FITNESS FOR A
90 * PARTICULAR PURPOSE.
91 *
92 * 4.2. IN NO EVENT SHALL INTEL HAVE ANY LIABILITY TO LICENSEE, ITS LICENSEES
93 * OR ANY OTHER THIRD PARTY, FOR ANY LOST PROFITS, LOST DATA, LOSS OF USE OR
94 * COSTS OF PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES, OR FOR ANY INDIRECT,
95 * SPECIAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THIS AGREEMENT, UNDER ANY
96 * CAUSE OF ACTION OR THEORY OF LIABILITY, AND IRRESPECTIVE OF WHETHER INTEL
97 * HAS ADVANCE NOTICE OF THE POSSIBILITY OF SUCH DAMAGES.  THESE LIMITATIONS
98 * SHALL APPLY NOTWITHSTANDING THE FAILURE OF THE ESSENTIAL PURPOSE OF ANY
99 * LIMITED REMEDY.
100 *
101 * 4.3. Licensee shall not export, either directly or indirectly, any of this
102 * software or system incorporating such software without first obtaining any
103 * required license or other approval from the U. S. Department of Commerce or
104 * any other agency or department of the United States Government.  In the
105 * event Licensee exports any such software from the United States or
106 * re-exports any such software from a foreign destination, Licensee shall
107 * ensure that the distribution and export/re-export of the software is in
108 * compliance with all laws, regulations, orders, or other restrictions of the
109 * U.S. Export Administration Regulations. Licensee agrees that neither it nor
110 * any of its subsidiaries will export/re-export any technical data, process,
111 * software, or service, directly or indirectly, to any country for which the
112 * United States government or any agency thereof requires an export license,
113 * other governmental approval, or letter of assurance, without first obtaining
114 * such license, approval or letter.
115 *
116 *****************************************************************************/
117
118#define __EXPREP_C__
119
120#include <contrib/dev/acpica/acpi.h>
121#include <contrib/dev/acpica/acinterp.h>
122#include <contrib/dev/acpica/amlcode.h>
123#include <contrib/dev/acpica/acnamesp.h>
124
125
126#define _COMPONENT          ACPI_EXECUTER
127        ACPI_MODULE_NAME    ("exprep")
128
129
130#ifdef ACPI_UNDER_DEVELOPMENT
131/*******************************************************************************
132 *
133 * FUNCTION:    AcpiExGenerateAccess
134 *
135 * PARAMETERS:  FieldBitOffset      - Start of field within parent region/buffer
136 *              FieldBitLength      - Length of field in bits
137 *              RegionLength        - Length of parent in bytes
138 *
139 * RETURN:      Field granularity (8, 16, 32 or 64) and
140 *              ByteAlignment (1, 2, 3, or 4)
141 *
142 * DESCRIPTION: Generate an optimal access width for fields defined with the
143 *              AnyAcc keyword.
144 *
145 * NOTE: Need to have the RegionLength in order to check for boundary
146 *       conditions (end-of-region).  However, the RegionLength is a deferred
147 *       operation.  Therefore, to complete this implementation, the generation
148 *       of this access width must be deferred until the region length has
149 *       been evaluated.
150 *
151 ******************************************************************************/
152
153static UINT32
154AcpiExGenerateAccess (
155    UINT32                  FieldBitOffset,
156    UINT32                  FieldBitLength,
157    UINT32                  RegionLength)
158{
159    UINT32                  FieldByteLength;
160    UINT32                  FieldByteOffset;
161    UINT32                  FieldByteEndOffset;
162    UINT32                  AccessByteWidth;
163    UINT32                  FieldStartOffset;
164    UINT32                  FieldEndOffset;
165    UINT32                  MinimumAccessWidth = 0xFFFFFFFF;
166    UINT32                  MinimumAccesses = 0xFFFFFFFF;
167    UINT32                  Accesses;
168
169
170    ACPI_FUNCTION_TRACE ("ExGenerateAccess");
171
172
173    /* Round Field start offset and length to "minimal" byte boundaries */
174
175    FieldByteOffset    = ACPI_DIV_8 (ACPI_ROUND_DOWN (FieldBitOffset, 8));
176    FieldByteEndOffset = ACPI_DIV_8 (ACPI_ROUND_UP   (FieldBitLength + FieldBitOffset, 8));
177    FieldByteLength    = FieldByteEndOffset - FieldByteOffset;
178
179    ACPI_DEBUG_PRINT ((ACPI_DB_BFIELD,
180            "Bit length %d, Bit offset %d\n",
181            FieldBitLength, FieldBitOffset));
182    ACPI_DEBUG_PRINT ((ACPI_DB_BFIELD,
183            "Byte Length %d, Byte Offset %d, End Offset %d\n",
184            FieldByteLength, FieldByteOffset, FieldByteEndOffset));
185
186    /*
187     * Iterative search for the maximum access width that is both aligned
188     * and does not go beyond the end of the region
189     *
190     * Start at ByteAcc and work upwards to QwordAcc max. (1,2,4,8 bytes)
191     */
192    for (AccessByteWidth = 1; AccessByteWidth <= 8; AccessByteWidth <<= 1)
193    {
194        /*
195         * 1) Round end offset up to next access boundary and make sure that this
196         *    does not go beyond the end of the parent region.
197         * 2) When the Access width is greater than the FieldByteLength, we are done.
198         *    (This does not optimize for the perfectly aligned case yet).
199         */
200        if (ACPI_ROUND_UP (FieldByteEndOffset, AccessByteWidth) <= RegionLength)
201        {
202            FieldStartOffset = ACPI_ROUND_DOWN (FieldByteOffset, AccessByteWidth) /
203                                                    AccessByteWidth;
204            FieldEndOffset   = ACPI_ROUND_UP   ((FieldByteLength + FieldByteOffset),
205                                                    AccessByteWidth) / AccessByteWidth;
206            Accesses         = FieldEndOffset - FieldStartOffset;
207
208            ACPI_DEBUG_PRINT ((ACPI_DB_BFIELD,
209                    "AccessWidth %d end is within region\n", AccessByteWidth));
210            ACPI_DEBUG_PRINT ((ACPI_DB_BFIELD,
211                    "Field Start %d, Field End %d -- requires %d accesses\n",
212                    FieldStartOffset, FieldEndOffset, Accesses));
213
214            /* Single access is optimal */
215
216            if (Accesses <= 1)
217            {
218                ACPI_DEBUG_PRINT ((ACPI_DB_BFIELD,
219                        "Entire field can be accessed with one operation of size %d\n",
220                        AccessByteWidth));
221                return_VALUE (AccessByteWidth);
222            }
223
224            /*
225             * Fits in the region, but requires more than one read/write.
226             * try the next wider access on next iteration
227             */
228            if (Accesses < MinimumAccesses)
229            {
230                MinimumAccesses    = Accesses;
231                MinimumAccessWidth = AccessByteWidth;
232            }
233        }
234        else
235        {
236            ACPI_DEBUG_PRINT ((ACPI_DB_BFIELD,
237                    "AccessWidth %d end is NOT within region\n", AccessByteWidth));
238            if (AccessByteWidth == 1)
239            {
240                ACPI_DEBUG_PRINT ((ACPI_DB_BFIELD,
241                        "Field goes beyond end-of-region!\n"));
242                return_VALUE (0);     /* Field does not fit in the region at all */
243            }
244
245            /* This width goes beyond the end-of-region, back off to previous access */
246
247            ACPI_DEBUG_PRINT ((ACPI_DB_BFIELD,
248                    "Backing off to previous optimal access width of %d\n",
249                    MinimumAccessWidth));
250            return_VALUE (MinimumAccessWidth);
251        }
252    }
253
254    /* Could not read/write field with one operation, just use max access width */
255
256    ACPI_DEBUG_PRINT ((ACPI_DB_BFIELD,
257            "Cannot access field in one operation, using width 8\n"));
258    return_VALUE (8);
259}
260#endif /* ACPI_UNDER_DEVELOPMENT */
261
262
263/*******************************************************************************
264 *
265 * FUNCTION:    AcpiExDecodeFieldAccess
266 *
267 * PARAMETERS:  Access          - Encoded field access bits
268 *              Length          - Field length.
269 *
270 * RETURN:      Field granularity (8, 16, 32 or 64) and
271 *              ByteAlignment (1, 2, 3, or 4)
272 *
273 * DESCRIPTION: Decode the AccessType bits of a field definition.
274 *
275 ******************************************************************************/
276
277static UINT32
278AcpiExDecodeFieldAccess (
279    ACPI_OPERAND_OBJECT     *ObjDesc,
280    UINT8                   FieldFlags,
281    UINT32                  *ReturnByteAlignment)
282{
283    UINT32                  Access;
284    UINT32                  ByteAlignment;
285    UINT32                  BitLength;
286
287
288    ACPI_FUNCTION_TRACE ("ExDecodeFieldAccess");
289
290
291    Access = (FieldFlags & AML_FIELD_ACCESS_TYPE_MASK);
292
293    switch (Access)
294    {
295    case AML_FIELD_ACCESS_ANY:
296
297#ifdef ACPI_UNDER_DEVELOPMENT
298        ByteAlignment = AcpiExGenerateAccess (ObjDesc->CommonField.StartFieldBitOffset,
299                                ObjDesc->CommonField.BitLength,
300                                0xFFFFFFFF /* Temp until we pass RegionLength as param */);
301        BitLength = ByteAlignment * 8;
302#endif
303
304        ByteAlignment = 1;
305        BitLength = 8;
306        break;
307
308    case AML_FIELD_ACCESS_BYTE:
309    case AML_FIELD_ACCESS_BUFFER:   /* ACPI 2.0 (SMBus Buffer) */
310        ByteAlignment = 1;
311        BitLength     = 8;
312        break;
313
314    case AML_FIELD_ACCESS_WORD:
315        ByteAlignment = 2;
316        BitLength     = 16;
317        break;
318
319    case AML_FIELD_ACCESS_DWORD:
320        ByteAlignment = 4;
321        BitLength     = 32;
322        break;
323
324    case AML_FIELD_ACCESS_QWORD:    /* ACPI 2.0 */
325        ByteAlignment = 8;
326        BitLength     = 64;
327        break;
328
329    default:
330        /* Invalid field access type */
331
332        ACPI_DEBUG_PRINT ((ACPI_DB_ERROR,
333            "Unknown field access type %X\n",
334            Access));
335        return_VALUE (0);
336    }
337
338    if (ACPI_GET_OBJECT_TYPE (ObjDesc) == ACPI_TYPE_BUFFER_FIELD)
339    {
340        /*
341         * BufferField access can be on any byte boundary, so the
342         * ByteAlignment is always 1 byte -- regardless of any ByteAlignment
343         * implied by the field access type.
344         */
345        ByteAlignment = 1;
346    }
347
348    *ReturnByteAlignment = ByteAlignment;
349    return_VALUE (BitLength);
350}
351
352
353/*******************************************************************************
354 *
355 * FUNCTION:    AcpiExPrepCommonFieldObject
356 *
357 * PARAMETERS:  ObjDesc             - The field object
358 *              FieldFlags          - Access, LockRule, and UpdateRule.
359 *                                    The format of a FieldFlag is described
360 *                                    in the ACPI specification
361 *              FieldBitPosition    - Field start position
362 *              FieldBitLength      - Field length in number of bits
363 *
364 * RETURN:      Status
365 *
366 * DESCRIPTION: Initialize the areas of the field object that are common
367 *              to the various types of fields.  Note: This is very "sensitive"
368 *              code because we are solving the general case for field
369 *              alignment.
370 *
371 ******************************************************************************/
372
373ACPI_STATUS
374AcpiExPrepCommonFieldObject (
375    ACPI_OPERAND_OBJECT     *ObjDesc,
376    UINT8                   FieldFlags,
377    UINT8                   FieldAttribute,
378    UINT32                  FieldBitPosition,
379    UINT32                  FieldBitLength)
380{
381    UINT32                  AccessBitWidth;
382    UINT32                  ByteAlignment;
383    UINT32                  NearestByteAddress;
384
385
386    ACPI_FUNCTION_TRACE ("ExPrepCommonFieldObject");
387
388
389    /*
390     * Note: the structure being initialized is the
391     * ACPI_COMMON_FIELD_INFO;  No structure fields outside of the common
392     * area are initialized by this procedure.
393     */
394    ObjDesc->CommonField.FieldFlags = FieldFlags;
395    ObjDesc->CommonField.Attribute  = FieldAttribute;
396    ObjDesc->CommonField.BitLength  = FieldBitLength;
397
398    /*
399     * Decode the access type so we can compute offsets.  The access type gives
400     * two pieces of information - the width of each field access and the
401     * necessary ByteAlignment (address granularity) of the access.
402     *
403     * For AnyAcc, the AccessBitWidth is the largest width that is both
404     * necessary and possible in an attempt to access the whole field in one
405     * I/O operation.  However, for AnyAcc, the ByteAlignment is always one
406     * byte.
407     *
408     * For all Buffer Fields, the ByteAlignment is always one byte.
409     *
410     * For all other access types (Byte, Word, Dword, Qword), the Bitwidth is
411     * the same (equivalent) as the ByteAlignment.
412     */
413    AccessBitWidth = AcpiExDecodeFieldAccess (ObjDesc, FieldFlags,
414                                &ByteAlignment);
415    if (!AccessBitWidth)
416    {
417        return_ACPI_STATUS (AE_AML_OPERAND_VALUE);
418    }
419
420    /* Setup width (access granularity) fields */
421
422    ObjDesc->CommonField.AccessByteWidth = (UINT8)
423            ACPI_DIV_8 (AccessBitWidth); /* 1,  2,  4,  8 */
424
425    /*
426     * BaseByteOffset is the address of the start of the field within the
427     * region.  It is the byte address of the first *datum* (field-width data
428     * unit) of the field. (i.e., the first datum that contains at least the
429     * first *bit* of the field.)
430     *
431     * Note: ByteAlignment is always either equal to the AccessBitWidth or 8
432     * (Byte access), and it defines the addressing granularity of the parent
433     * region or buffer.
434     */
435    NearestByteAddress =
436            ACPI_ROUND_BITS_DOWN_TO_BYTES (FieldBitPosition);
437    ObjDesc->CommonField.BaseByteOffset = (UINT32)
438            ACPI_ROUND_DOWN (NearestByteAddress, ByteAlignment);
439
440    /*
441     * StartFieldBitOffset is the offset of the first bit of the field within
442     * a field datum.
443     */
444    ObjDesc->CommonField.StartFieldBitOffset = (UINT8)
445        (FieldBitPosition - ACPI_MUL_8 (ObjDesc->CommonField.BaseByteOffset));
446
447    /*
448     * Valid bits -- the number of bits that compose a partial datum,
449     * 1) At the end of the field within the region (arbitrary starting bit
450     *    offset)
451     * 2) At the end of a buffer used to contain the field (starting offset
452     *    always zero)
453     */
454    ObjDesc->CommonField.EndFieldValidBits   = (UINT8)
455        ((ObjDesc->CommonField.StartFieldBitOffset + FieldBitLength) %
456                                                            AccessBitWidth);
457    /* StartBufferBitOffset always = 0 */
458
459    ObjDesc->CommonField.EndBufferValidBits  = (UINT8)
460        (FieldBitLength % AccessBitWidth);
461
462    /*
463     * DatumValidBits is the number of valid field bits in the first
464     * field datum.
465     */
466    ObjDesc->CommonField.DatumValidBits      = (UINT8)
467        (AccessBitWidth - ObjDesc->CommonField.StartFieldBitOffset);
468
469    /*
470     * Does the entire field fit within a single field access element? (datum)
471     * (i.e., without crossing a datum boundary)
472     */
473    if ((ObjDesc->CommonField.StartFieldBitOffset + FieldBitLength) <=
474            (UINT16) AccessBitWidth)
475    {
476        ObjDesc->Common.Flags |= AOPOBJ_SINGLE_DATUM;
477    }
478
479    return_ACPI_STATUS (AE_OK);
480}
481
482
483/*******************************************************************************
484 *
485 * FUNCTION:    AcpiExPrepFieldValue
486 *
487 * PARAMETERS:  Node                - Owning Node
488 *              RegionNode          - Region in which field is being defined
489 *              FieldFlags          - Access, LockRule, and UpdateRule.
490 *              FieldBitPosition    - Field start position
491 *              FieldBitLength      - Field length in number of bits
492 *
493 * RETURN:      Status
494 *
495 * DESCRIPTION: Construct an ACPI_OPERAND_OBJECT of type DefField and
496 *              connect it to the parent Node.
497 *
498 ******************************************************************************/
499
500ACPI_STATUS
501AcpiExPrepFieldValue (
502    ACPI_CREATE_FIELD_INFO  *Info)
503{
504    ACPI_OPERAND_OBJECT     *ObjDesc;
505    UINT32                  Type;
506    ACPI_STATUS             Status;
507
508
509    ACPI_FUNCTION_TRACE ("ExPrepFieldValue");
510
511
512    /* Parameter validation */
513
514    if (Info->FieldType != ACPI_TYPE_LOCAL_INDEX_FIELD)
515    {
516        if (!Info->RegionNode)
517        {
518            ACPI_DEBUG_PRINT ((ACPI_DB_ERROR, "Null RegionNode\n"));
519            return_ACPI_STATUS (AE_AML_NO_OPERAND);
520        }
521
522        Type = AcpiNsGetType (Info->RegionNode);
523        if (Type != ACPI_TYPE_REGION)
524        {
525            ACPI_DEBUG_PRINT ((ACPI_DB_ERROR,
526                "Needed Region, found type %X (%s)\n",
527                Type, AcpiUtGetTypeName (Type)));
528
529            return_ACPI_STATUS (AE_AML_OPERAND_TYPE);
530        }
531    }
532
533    /* Allocate a new field object */
534
535    ObjDesc = AcpiUtCreateInternalObject (Info->FieldType);
536    if (!ObjDesc)
537    {
538        return_ACPI_STATUS (AE_NO_MEMORY);
539    }
540
541    /* Initialize areas of the object that are common to all fields */
542
543    ObjDesc->CommonField.Node = Info->FieldNode;
544    Status = AcpiExPrepCommonFieldObject (ObjDesc, Info->FieldFlags,
545                Info->Attribute, Info->FieldBitPosition, Info->FieldBitLength);
546    if (ACPI_FAILURE (Status))
547    {
548        AcpiUtDeleteObjectDesc (ObjDesc);
549        return_ACPI_STATUS (Status);
550    }
551
552    /* Initialize areas of the object that are specific to the field type */
553
554    switch (Info->FieldType)
555    {
556    case ACPI_TYPE_LOCAL_REGION_FIELD:
557
558        ObjDesc->Field.RegionObj     = AcpiNsGetAttachedObject (Info->RegionNode);
559
560        /* An additional reference for the container */
561
562        AcpiUtAddReference (ObjDesc->Field.RegionObj);
563
564        ACPI_DEBUG_PRINT ((ACPI_DB_BFIELD,
565            "RegionField: BitOff %X, Off %X, Gran %X, Region %p\n",
566            ObjDesc->Field.StartFieldBitOffset, ObjDesc->Field.BaseByteOffset,
567            ObjDesc->Field.AccessByteWidth, ObjDesc->Field.RegionObj));
568        break;
569
570
571    case ACPI_TYPE_LOCAL_BANK_FIELD:
572
573        ObjDesc->BankField.Value     = Info->BankValue;
574        ObjDesc->BankField.RegionObj = AcpiNsGetAttachedObject (Info->RegionNode);
575        ObjDesc->BankField.BankObj   = AcpiNsGetAttachedObject (Info->RegisterNode);
576
577        /* An additional reference for the attached objects */
578
579        AcpiUtAddReference (ObjDesc->BankField.RegionObj);
580        AcpiUtAddReference (ObjDesc->BankField.BankObj);
581
582        ACPI_DEBUG_PRINT ((ACPI_DB_BFIELD,
583            "Bank Field: BitOff %X, Off %X, Gran %X, Region %p, BankReg %p\n",
584            ObjDesc->BankField.StartFieldBitOffset,
585            ObjDesc->BankField.BaseByteOffset,
586            ObjDesc->Field.AccessByteWidth,
587            ObjDesc->BankField.RegionObj,
588            ObjDesc->BankField.BankObj));
589        break;
590
591
592    case ACPI_TYPE_LOCAL_INDEX_FIELD:
593
594        ObjDesc->IndexField.IndexObj = AcpiNsGetAttachedObject (Info->RegisterNode);
595        ObjDesc->IndexField.DataObj  = AcpiNsGetAttachedObject (Info->DataRegisterNode);
596        ObjDesc->IndexField.Value    = (UINT32)
597            (Info->FieldBitPosition / ACPI_MUL_8 (ObjDesc->Field.AccessByteWidth));
598
599        if (!ObjDesc->IndexField.DataObj || !ObjDesc->IndexField.IndexObj)
600        {
601            ACPI_REPORT_ERROR (("Null Index Object during field prep\n"));
602            AcpiUtDeleteObjectDesc (ObjDesc);
603            return_ACPI_STATUS (AE_AML_INTERNAL);
604        }
605
606        /* An additional reference for the attached objects */
607
608        AcpiUtAddReference (ObjDesc->IndexField.DataObj);
609        AcpiUtAddReference (ObjDesc->IndexField.IndexObj);
610
611        ACPI_DEBUG_PRINT ((ACPI_DB_BFIELD,
612            "IndexField: BitOff %X, Off %X, Value %X, Gran %X, Index %p, Data %p\n",
613            ObjDesc->IndexField.StartFieldBitOffset,
614            ObjDesc->IndexField.BaseByteOffset,
615            ObjDesc->IndexField.Value,
616            ObjDesc->Field.AccessByteWidth,
617            ObjDesc->IndexField.IndexObj,
618            ObjDesc->IndexField.DataObj));
619        break;
620
621    default:
622        /* No other types should get here */
623        break;
624    }
625
626    /*
627     * Store the constructed descriptor (ObjDesc) into the parent Node,
628     * preserving the current type of that NamedObj.
629     */
630    Status = AcpiNsAttachObject (Info->FieldNode, ObjDesc,
631                    AcpiNsGetType (Info->FieldNode));
632
633    ACPI_DEBUG_PRINT ((ACPI_DB_BFIELD, "Set NamedObj %p [%4.4s], ObjDesc %p\n",
634            Info->FieldNode, AcpiUtGetNodeName (Info->FieldNode), ObjDesc));
635
636    /* Remove local reference to the object */
637
638    AcpiUtRemoveReference (ObjDesc);
639    return_ACPI_STATUS (Status);
640}
641
642