ACPI: ACPICA 20060608
[sfrench/cifs-2.6.git] / drivers / acpi / executer / exfldio.c
1 /******************************************************************************
2  *
3  * Module Name: exfldio - Aml Field I/O
4  *
5  *****************************************************************************/
6
7 /*
8  * Copyright (C) 2000 - 2006, R. Byron Moore
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 #include <acpi/acpi.h>
45 #include <acpi/acinterp.h>
46 #include <acpi/amlcode.h>
47 #include <acpi/acevents.h>
48 #include <acpi/acdispat.h>
49
50 #define _COMPONENT          ACPI_EXECUTER
51 ACPI_MODULE_NAME("exfldio")
52
53 /* Local prototypes */
54 static acpi_status
55 acpi_ex_field_datum_io(union acpi_operand_object *obj_desc,
56                        u32 field_datum_byte_offset,
57                        acpi_integer * value, u32 read_write);
58
59 static u8
60 acpi_ex_register_overflow(union acpi_operand_object *obj_desc,
61                           acpi_integer value);
62
63 static acpi_status
64 acpi_ex_setup_region(union acpi_operand_object *obj_desc,
65                      u32 field_datum_byte_offset);
66
67 /*******************************************************************************
68  *
69  * FUNCTION:    acpi_ex_setup_region
70  *
71  * PARAMETERS:  obj_desc                - Field to be read or written
72  *              field_datum_byte_offset - Byte offset of this datum within the
73  *                                        parent field
74  *
75  * RETURN:      Status
76  *
77  * DESCRIPTION: Common processing for acpi_ex_extract_from_field and
78  *              acpi_ex_insert_into_field. Initialize the Region if necessary and
79  *              validate the request.
80  *
81  ******************************************************************************/
82
83 static acpi_status
84 acpi_ex_setup_region(union acpi_operand_object *obj_desc,
85                      u32 field_datum_byte_offset)
86 {
87         acpi_status status = AE_OK;
88         union acpi_operand_object *rgn_desc;
89
90         ACPI_FUNCTION_TRACE_U32(ex_setup_region, field_datum_byte_offset);
91
92         rgn_desc = obj_desc->common_field.region_obj;
93
94         /* We must have a valid region */
95
96         if (ACPI_GET_OBJECT_TYPE(rgn_desc) != ACPI_TYPE_REGION) {
97                 ACPI_ERROR((AE_INFO, "Needed Region, found type %X (%s)",
98                             ACPI_GET_OBJECT_TYPE(rgn_desc),
99                             acpi_ut_get_object_type_name(rgn_desc)));
100
101                 return_ACPI_STATUS(AE_AML_OPERAND_TYPE);
102         }
103
104         /*
105          * If the Region Address and Length have not been previously evaluated,
106          * evaluate them now and save the results.
107          */
108         if (!(rgn_desc->common.flags & AOPOBJ_DATA_VALID)) {
109                 status = acpi_ds_get_region_arguments(rgn_desc);
110                 if (ACPI_FAILURE(status)) {
111                         return_ACPI_STATUS(status);
112                 }
113         }
114
115         /* Exit if Address/Length have been disallowed by the host OS */
116
117         if (rgn_desc->common.flags & AOPOBJ_INVALID) {
118                 return_ACPI_STATUS(AE_AML_ILLEGAL_ADDRESS);
119         }
120
121         /*
122          * Exit now for SMBus address space, it has a non-linear address space
123          * and the request cannot be directly validated
124          */
125         if (rgn_desc->region.space_id == ACPI_ADR_SPACE_SMBUS) {
126
127                 /* SMBus has a non-linear address space */
128
129                 return_ACPI_STATUS(AE_OK);
130         }
131 #ifdef ACPI_UNDER_DEVELOPMENT
132         /*
133          * If the Field access is any_acc, we can now compute the optimal
134          * access (because we know know the length of the parent region)
135          */
136         if (!(obj_desc->common.flags & AOPOBJ_DATA_VALID)) {
137                 if (ACPI_FAILURE(status)) {
138                         return_ACPI_STATUS(status);
139                 }
140         }
141 #endif
142
143         /*
144          * Validate the request.  The entire request from the byte offset for a
145          * length of one field datum (access width) must fit within the region.
146          * (Region length is specified in bytes)
147          */
148         if (rgn_desc->region.length <
149             (obj_desc->common_field.base_byte_offset +
150              field_datum_byte_offset +
151              obj_desc->common_field.access_byte_width)) {
152                 if (acpi_gbl_enable_interpreter_slack) {
153                         /*
154                          * Slack mode only:  We will go ahead and allow access to this
155                          * field if it is within the region length rounded up to the next
156                          * access width boundary.
157                          */
158                         if (ACPI_ROUND_UP(rgn_desc->region.length,
159                                           obj_desc->common_field.
160                                           access_byte_width) >=
161                             (obj_desc->common_field.base_byte_offset +
162                              (acpi_native_uint) obj_desc->common_field.
163                              access_byte_width + field_datum_byte_offset)) {
164                                 return_ACPI_STATUS(AE_OK);
165                         }
166                 }
167
168                 if (rgn_desc->region.length <
169                     obj_desc->common_field.access_byte_width) {
170                         /*
171                          * This is the case where the access_type (acc_word, etc.) is wider
172                          * than the region itself.  For example, a region of length one
173                          * byte, and a field with Dword access specified.
174                          */
175                         ACPI_ERROR((AE_INFO,
176                                     "Field [%4.4s] access width (%d bytes) too large for region [%4.4s] (length %X)",
177                                     acpi_ut_get_node_name(obj_desc->
178                                                           common_field.node),
179                                     obj_desc->common_field.access_byte_width,
180                                     acpi_ut_get_node_name(rgn_desc->region.
181                                                           node),
182                                     rgn_desc->region.length));
183                 }
184
185                 /*
186                  * Offset rounded up to next multiple of field width
187                  * exceeds region length, indicate an error
188                  */
189                 ACPI_ERROR((AE_INFO,
190                             "Field [%4.4s] Base+Offset+Width %X+%X+%X is beyond end of region [%4.4s] (length %X)",
191                             acpi_ut_get_node_name(obj_desc->common_field.node),
192                             obj_desc->common_field.base_byte_offset,
193                             field_datum_byte_offset,
194                             obj_desc->common_field.access_byte_width,
195                             acpi_ut_get_node_name(rgn_desc->region.node),
196                             rgn_desc->region.length));
197
198                 return_ACPI_STATUS(AE_AML_REGION_LIMIT);
199         }
200
201         return_ACPI_STATUS(AE_OK);
202 }
203
204 /*******************************************************************************
205  *
206  * FUNCTION:    acpi_ex_access_region
207  *
208  * PARAMETERS:  obj_desc                - Field to be read
209  *              field_datum_byte_offset - Byte offset of this datum within the
210  *                                        parent field
211  *              Value                   - Where to store value (must at least
212  *                                        the size of acpi_integer)
213  *              Function                - Read or Write flag plus other region-
214  *                                        dependent flags
215  *
216  * RETURN:      Status
217  *
218  * DESCRIPTION: Read or Write a single field datum to an Operation Region.
219  *
220  ******************************************************************************/
221
222 acpi_status
223 acpi_ex_access_region(union acpi_operand_object *obj_desc,
224                       u32 field_datum_byte_offset,
225                       acpi_integer * value, u32 function)
226 {
227         acpi_status status;
228         union acpi_operand_object *rgn_desc;
229         acpi_physical_address address;
230
231         ACPI_FUNCTION_TRACE(ex_access_region);
232
233         /*
234          * Ensure that the region operands are fully evaluated and verify
235          * the validity of the request
236          */
237         status = acpi_ex_setup_region(obj_desc, field_datum_byte_offset);
238         if (ACPI_FAILURE(status)) {
239                 return_ACPI_STATUS(status);
240         }
241
242         /*
243          * The physical address of this field datum is:
244          *
245          * 1) The base of the region, plus
246          * 2) The base offset of the field, plus
247          * 3) The current offset into the field
248          */
249         rgn_desc = obj_desc->common_field.region_obj;
250         address = rgn_desc->region.address +
251             obj_desc->common_field.base_byte_offset + field_datum_byte_offset;
252
253         if ((function & ACPI_IO_MASK) == ACPI_READ) {
254                 ACPI_DEBUG_PRINT((ACPI_DB_BFIELD, "[READ]"));
255         } else {
256                 ACPI_DEBUG_PRINT((ACPI_DB_BFIELD, "[WRITE]"));
257         }
258
259         ACPI_DEBUG_PRINT_RAW((ACPI_DB_BFIELD,
260                               " Region [%s:%X], Width %X, ByteBase %X, Offset %X at %8.8X%8.8X\n",
261                               acpi_ut_get_region_name(rgn_desc->region.
262                                                       space_id),
263                               rgn_desc->region.space_id,
264                               obj_desc->common_field.access_byte_width,
265                               obj_desc->common_field.base_byte_offset,
266                               field_datum_byte_offset,
267                               ACPI_FORMAT_UINT64(address)));
268
269         /* Invoke the appropriate address_space/op_region handler */
270
271         status = acpi_ev_address_space_dispatch(rgn_desc, function,
272                                                 address,
273                                                 ACPI_MUL_8(obj_desc->
274                                                            common_field.
275                                                            access_byte_width),
276                                                 value);
277
278         if (ACPI_FAILURE(status)) {
279                 if (status == AE_NOT_IMPLEMENTED) {
280                         ACPI_ERROR((AE_INFO,
281                                     "Region %s(%X) not implemented",
282                                     acpi_ut_get_region_name(rgn_desc->region.
283                                                             space_id),
284                                     rgn_desc->region.space_id));
285                 } else if (status == AE_NOT_EXIST) {
286                         ACPI_ERROR((AE_INFO,
287                                     "Region %s(%X) has no handler",
288                                     acpi_ut_get_region_name(rgn_desc->region.
289                                                             space_id),
290                                     rgn_desc->region.space_id));
291                 }
292         }
293
294         return_ACPI_STATUS(status);
295 }
296
297 /*******************************************************************************
298  *
299  * FUNCTION:    acpi_ex_register_overflow
300  *
301  * PARAMETERS:  obj_desc                - Register(Field) to be written
302  *              Value                   - Value to be stored
303  *
304  * RETURN:      TRUE if value overflows the field, FALSE otherwise
305  *
306  * DESCRIPTION: Check if a value is out of range of the field being written.
307  *              Used to check if the values written to Index and Bank registers
308  *              are out of range.  Normally, the value is simply truncated
309  *              to fit the field, but this case is most likely a serious
310  *              coding error in the ASL.
311  *
312  ******************************************************************************/
313
314 static u8
315 acpi_ex_register_overflow(union acpi_operand_object *obj_desc,
316                           acpi_integer value)
317 {
318
319         if (obj_desc->common_field.bit_length >= ACPI_INTEGER_BIT_SIZE) {
320                 /*
321                  * The field is large enough to hold the maximum integer, so we can
322                  * never overflow it.
323                  */
324                 return (FALSE);
325         }
326
327         if (value >= ((acpi_integer) 1 << obj_desc->common_field.bit_length)) {
328                 /*
329                  * The Value is larger than the maximum value that can fit into
330                  * the register.
331                  */
332                 return (TRUE);
333         }
334
335         /* The Value will fit into the field with no truncation */
336
337         return (FALSE);
338 }
339
340 /*******************************************************************************
341  *
342  * FUNCTION:    acpi_ex_field_datum_io
343  *
344  * PARAMETERS:  obj_desc                - Field to be read
345  *              field_datum_byte_offset - Byte offset of this datum within the
346  *                                        parent field
347  *              Value                   - Where to store value (must be 64 bits)
348  *              read_write              - Read or Write flag
349  *
350  * RETURN:      Status
351  *
352  * DESCRIPTION: Read or Write a single datum of a field.  The field_type is
353  *              demultiplexed here to handle the different types of fields
354  *              (buffer_field, region_field, index_field, bank_field)
355  *
356  ******************************************************************************/
357
358 static acpi_status
359 acpi_ex_field_datum_io(union acpi_operand_object *obj_desc,
360                        u32 field_datum_byte_offset,
361                        acpi_integer * value, u32 read_write)
362 {
363         acpi_status status;
364         acpi_integer local_value;
365
366         ACPI_FUNCTION_TRACE_U32(ex_field_datum_io, field_datum_byte_offset);
367
368         if (read_write == ACPI_READ) {
369                 if (!value) {
370                         local_value = 0;
371
372                         /* To support reads without saving return value */
373                         value = &local_value;
374                 }
375
376                 /* Clear the entire return buffer first, [Very Important!] */
377
378                 *value = 0;
379         }
380
381         /*
382          * The four types of fields are:
383          *
384          * buffer_field - Read/write from/to a Buffer
385          * region_field - Read/write from/to a Operation Region.
386          * bank_field  - Write to a Bank Register, then read/write from/to an
387          *               operation_region
388          * index_field - Write to an Index Register, then read/write from/to a
389          *               Data Register
390          */
391         switch (ACPI_GET_OBJECT_TYPE(obj_desc)) {
392         case ACPI_TYPE_BUFFER_FIELD:
393                 /*
394                  * If the buffer_field arguments have not been previously evaluated,
395                  * evaluate them now and save the results.
396                  */
397                 if (!(obj_desc->common.flags & AOPOBJ_DATA_VALID)) {
398                         status = acpi_ds_get_buffer_field_arguments(obj_desc);
399                         if (ACPI_FAILURE(status)) {
400                                 return_ACPI_STATUS(status);
401                         }
402                 }
403
404                 if (read_write == ACPI_READ) {
405                         /*
406                          * Copy the data from the source buffer.
407                          * Length is the field width in bytes.
408                          */
409                         ACPI_MEMCPY(value,
410                                     (obj_desc->buffer_field.buffer_obj)->buffer.
411                                     pointer +
412                                     obj_desc->buffer_field.base_byte_offset +
413                                     field_datum_byte_offset,
414                                     obj_desc->common_field.access_byte_width);
415                 } else {
416                         /*
417                          * Copy the data to the target buffer.
418                          * Length is the field width in bytes.
419                          */
420                         ACPI_MEMCPY((obj_desc->buffer_field.buffer_obj)->buffer.
421                                     pointer +
422                                     obj_desc->buffer_field.base_byte_offset +
423                                     field_datum_byte_offset, value,
424                                     obj_desc->common_field.access_byte_width);
425                 }
426
427                 status = AE_OK;
428                 break;
429
430         case ACPI_TYPE_LOCAL_BANK_FIELD:
431
432                 /*
433                  * Ensure that the bank_value is not beyond the capacity of
434                  * the register
435                  */
436                 if (acpi_ex_register_overflow(obj_desc->bank_field.bank_obj,
437                                               (acpi_integer) obj_desc->
438                                               bank_field.value)) {
439                         return_ACPI_STATUS(AE_AML_REGISTER_LIMIT);
440                 }
441
442                 /*
443                  * For bank_fields, we must write the bank_value to the bank_register
444                  * (itself a region_field) before we can access the data.
445                  */
446                 status =
447                     acpi_ex_insert_into_field(obj_desc->bank_field.bank_obj,
448                                               &obj_desc->bank_field.value,
449                                               sizeof(obj_desc->bank_field.
450                                                      value));
451                 if (ACPI_FAILURE(status)) {
452                         return_ACPI_STATUS(status);
453                 }
454
455                 /*
456                  * Now that the Bank has been selected, fall through to the
457                  * region_field case and write the datum to the Operation Region
458                  */
459
460                 /*lint -fallthrough */
461
462         case ACPI_TYPE_LOCAL_REGION_FIELD:
463                 /*
464                  * For simple region_fields, we just directly access the owning
465                  * Operation Region.
466                  */
467                 status =
468                     acpi_ex_access_region(obj_desc, field_datum_byte_offset,
469                                           value, read_write);
470                 break;
471
472         case ACPI_TYPE_LOCAL_INDEX_FIELD:
473
474                 /*
475                  * Ensure that the index_value is not beyond the capacity of
476                  * the register
477                  */
478                 if (acpi_ex_register_overflow(obj_desc->index_field.index_obj,
479                                               (acpi_integer) obj_desc->
480                                               index_field.value)) {
481                         return_ACPI_STATUS(AE_AML_REGISTER_LIMIT);
482                 }
483
484                 /* Write the index value to the index_register (itself a region_field) */
485
486                 field_datum_byte_offset += obj_desc->index_field.value;
487
488                 ACPI_DEBUG_PRINT((ACPI_DB_BFIELD,
489                                   "Write to Index Register: Value %8.8X\n",
490                                   field_datum_byte_offset));
491
492                 status =
493                     acpi_ex_insert_into_field(obj_desc->index_field.index_obj,
494                                               &field_datum_byte_offset,
495                                               sizeof(field_datum_byte_offset));
496                 if (ACPI_FAILURE(status)) {
497                         return_ACPI_STATUS(status);
498                 }
499
500                 ACPI_DEBUG_PRINT((ACPI_DB_BFIELD,
501                                   "I/O to Data Register: ValuePtr %p\n",
502                                   value));
503
504                 if (read_write == ACPI_READ) {
505
506                         /* Read the datum from the data_register */
507
508                         status =
509                             acpi_ex_extract_from_field(obj_desc->index_field.
510                                                        data_obj, value,
511                                                        sizeof(acpi_integer));
512                 } else {
513                         /* Write the datum to the data_register */
514
515                         status =
516                             acpi_ex_insert_into_field(obj_desc->index_field.
517                                                       data_obj, value,
518                                                       sizeof(acpi_integer));
519                 }
520                 break;
521
522         default:
523
524                 ACPI_ERROR((AE_INFO, "Wrong object type in field I/O %X",
525                             ACPI_GET_OBJECT_TYPE(obj_desc)));
526                 status = AE_AML_INTERNAL;
527                 break;
528         }
529
530         if (ACPI_SUCCESS(status)) {
531                 if (read_write == ACPI_READ) {
532                         ACPI_DEBUG_PRINT((ACPI_DB_BFIELD,
533                                           "Value Read %8.8X%8.8X, Width %d\n",
534                                           ACPI_FORMAT_UINT64(*value),
535                                           obj_desc->common_field.
536                                           access_byte_width));
537                 } else {
538                         ACPI_DEBUG_PRINT((ACPI_DB_BFIELD,
539                                           "Value Written %8.8X%8.8X, Width %d\n",
540                                           ACPI_FORMAT_UINT64(*value),
541                                           obj_desc->common_field.
542                                           access_byte_width));
543                 }
544         }
545
546         return_ACPI_STATUS(status);
547 }
548
549 /*******************************************************************************
550  *
551  * FUNCTION:    acpi_ex_write_with_update_rule
552  *
553  * PARAMETERS:  obj_desc                - Field to be written
554  *              Mask                    - bitmask within field datum
555  *              field_value             - Value to write
556  *              field_datum_byte_offset - Offset of datum within field
557  *
558  * RETURN:      Status
559  *
560  * DESCRIPTION: Apply the field update rule to a field write
561  *
562  ******************************************************************************/
563
564 acpi_status
565 acpi_ex_write_with_update_rule(union acpi_operand_object *obj_desc,
566                                acpi_integer mask,
567                                acpi_integer field_value,
568                                u32 field_datum_byte_offset)
569 {
570         acpi_status status = AE_OK;
571         acpi_integer merged_value;
572         acpi_integer current_value;
573
574         ACPI_FUNCTION_TRACE_U32(ex_write_with_update_rule, mask);
575
576         /* Start with the new bits  */
577
578         merged_value = field_value;
579
580         /* If the mask is all ones, we don't need to worry about the update rule */
581
582         if (mask != ACPI_INTEGER_MAX) {
583
584                 /* Decode the update rule */
585
586                 switch (obj_desc->common_field.
587                         field_flags & AML_FIELD_UPDATE_RULE_MASK) {
588                 case AML_FIELD_UPDATE_PRESERVE:
589                         /*
590                          * Check if update rule needs to be applied (not if mask is all
591                          * ones)  The left shift drops the bits we want to ignore.
592                          */
593                         if ((~mask << (ACPI_MUL_8(sizeof(mask)) -
594                                        ACPI_MUL_8(obj_desc->common_field.
595                                                   access_byte_width))) != 0) {
596                                 /*
597                                  * Read the current contents of the byte/word/dword containing
598                                  * the field, and merge with the new field value.
599                                  */
600                                 status =
601                                     acpi_ex_field_datum_io(obj_desc,
602                                                            field_datum_byte_offset,
603                                                            &current_value,
604                                                            ACPI_READ);
605                                 if (ACPI_FAILURE(status)) {
606                                         return_ACPI_STATUS(status);
607                                 }
608
609                                 merged_value |= (current_value & ~mask);
610                         }
611                         break;
612
613                 case AML_FIELD_UPDATE_WRITE_AS_ONES:
614
615                         /* Set positions outside the field to all ones */
616
617                         merged_value |= ~mask;
618                         break;
619
620                 case AML_FIELD_UPDATE_WRITE_AS_ZEROS:
621
622                         /* Set positions outside the field to all zeros */
623
624                         merged_value &= mask;
625                         break;
626
627                 default:
628
629                         ACPI_ERROR((AE_INFO,
630                                     "Unknown UpdateRule value: %X",
631                                     (obj_desc->common_field.
632                                      field_flags &
633                                      AML_FIELD_UPDATE_RULE_MASK)));
634                         return_ACPI_STATUS(AE_AML_OPERAND_VALUE);
635                 }
636         }
637
638         ACPI_DEBUG_PRINT((ACPI_DB_BFIELD,
639                           "Mask %8.8X%8.8X, DatumOffset %X, Width %X, Value %8.8X%8.8X, MergedValue %8.8X%8.8X\n",
640                           ACPI_FORMAT_UINT64(mask),
641                           field_datum_byte_offset,
642                           obj_desc->common_field.access_byte_width,
643                           ACPI_FORMAT_UINT64(field_value),
644                           ACPI_FORMAT_UINT64(merged_value)));
645
646         /* Write the merged value */
647
648         status = acpi_ex_field_datum_io(obj_desc, field_datum_byte_offset,
649                                         &merged_value, ACPI_WRITE);
650
651         return_ACPI_STATUS(status);
652 }
653
654 /*******************************************************************************
655  *
656  * FUNCTION:    acpi_ex_extract_from_field
657  *
658  * PARAMETERS:  obj_desc            - Field to be read
659  *              Buffer              - Where to store the field data
660  *              buffer_length       - Length of Buffer
661  *
662  * RETURN:      Status
663  *
664  * DESCRIPTION: Retrieve the current value of the given field
665  *
666  ******************************************************************************/
667
668 acpi_status
669 acpi_ex_extract_from_field(union acpi_operand_object *obj_desc,
670                            void *buffer, u32 buffer_length)
671 {
672         acpi_status status;
673         acpi_integer raw_datum;
674         acpi_integer merged_datum;
675         u32 field_offset = 0;
676         u32 buffer_offset = 0;
677         u32 buffer_tail_bits;
678         u32 datum_count;
679         u32 field_datum_count;
680         u32 i;
681
682         ACPI_FUNCTION_TRACE(ex_extract_from_field);
683
684         /* Validate target buffer and clear it */
685
686         if (buffer_length <
687             ACPI_ROUND_BITS_UP_TO_BYTES(obj_desc->common_field.bit_length)) {
688                 ACPI_ERROR((AE_INFO,
689                             "Field size %X (bits) is too large for buffer (%X)",
690                             obj_desc->common_field.bit_length, buffer_length));
691
692                 return_ACPI_STATUS(AE_BUFFER_OVERFLOW);
693         }
694         ACPI_MEMSET(buffer, 0, buffer_length);
695
696         /* Compute the number of datums (access width data items) */
697
698         datum_count = ACPI_ROUND_UP_TO(obj_desc->common_field.bit_length,
699                                        obj_desc->common_field.access_bit_width);
700         field_datum_count = ACPI_ROUND_UP_TO(obj_desc->common_field.bit_length +
701                                              obj_desc->common_field.
702                                              start_field_bit_offset,
703                                              obj_desc->common_field.
704                                              access_bit_width);
705
706         /* Priming read from the field */
707
708         status =
709             acpi_ex_field_datum_io(obj_desc, field_offset, &raw_datum,
710                                    ACPI_READ);
711         if (ACPI_FAILURE(status)) {
712                 return_ACPI_STATUS(status);
713         }
714         merged_datum =
715             raw_datum >> obj_desc->common_field.start_field_bit_offset;
716
717         /* Read the rest of the field */
718
719         for (i = 1; i < field_datum_count; i++) {
720
721                 /* Get next input datum from the field */
722
723                 field_offset += obj_desc->common_field.access_byte_width;
724                 status = acpi_ex_field_datum_io(obj_desc, field_offset,
725                                                 &raw_datum, ACPI_READ);
726                 if (ACPI_FAILURE(status)) {
727                         return_ACPI_STATUS(status);
728                 }
729
730                 /* Merge with previous datum if necessary */
731
732                 merged_datum |= raw_datum <<
733                     (obj_desc->common_field.access_bit_width -
734                      obj_desc->common_field.start_field_bit_offset);
735
736                 if (i == datum_count) {
737                         break;
738                 }
739
740                 /* Write merged datum to target buffer */
741
742                 ACPI_MEMCPY(((char *)buffer) + buffer_offset, &merged_datum,
743                             ACPI_MIN(obj_desc->common_field.access_byte_width,
744                                      buffer_length - buffer_offset));
745
746                 buffer_offset += obj_desc->common_field.access_byte_width;
747                 merged_datum =
748                     raw_datum >> obj_desc->common_field.start_field_bit_offset;
749         }
750
751         /* Mask off any extra bits in the last datum */
752
753         buffer_tail_bits = obj_desc->common_field.bit_length %
754             obj_desc->common_field.access_bit_width;
755         if (buffer_tail_bits) {
756                 merged_datum &= ACPI_MASK_BITS_ABOVE(buffer_tail_bits);
757         }
758
759         /* Write the last datum to the buffer */
760
761         ACPI_MEMCPY(((char *)buffer) + buffer_offset, &merged_datum,
762                     ACPI_MIN(obj_desc->common_field.access_byte_width,
763                              buffer_length - buffer_offset));
764
765         return_ACPI_STATUS(AE_OK);
766 }
767
768 /*******************************************************************************
769  *
770  * FUNCTION:    acpi_ex_insert_into_field
771  *
772  * PARAMETERS:  obj_desc            - Field to be written
773  *              Buffer              - Data to be written
774  *              buffer_length       - Length of Buffer
775  *
776  * RETURN:      Status
777  *
778  * DESCRIPTION: Store the Buffer contents into the given field
779  *
780  ******************************************************************************/
781
782 acpi_status
783 acpi_ex_insert_into_field(union acpi_operand_object *obj_desc,
784                           void *buffer, u32 buffer_length)
785 {
786         acpi_status status;
787         acpi_integer mask;
788         acpi_integer width_mask;
789         acpi_integer merged_datum;
790         acpi_integer raw_datum = 0;
791         u32 field_offset = 0;
792         u32 buffer_offset = 0;
793         u32 buffer_tail_bits;
794         u32 datum_count;
795         u32 field_datum_count;
796         u32 i;
797
798         ACPI_FUNCTION_TRACE(ex_insert_into_field);
799
800         /* Validate input buffer */
801
802         if (buffer_length <
803             ACPI_ROUND_BITS_UP_TO_BYTES(obj_desc->common_field.bit_length)) {
804                 ACPI_ERROR((AE_INFO,
805                             "Field size %X (bits) is too large for buffer (%X)",
806                             obj_desc->common_field.bit_length, buffer_length));
807
808                 return_ACPI_STATUS(AE_BUFFER_OVERFLOW);
809         }
810
811         /* Compute the number of datums (access width data items) */
812
813         width_mask =
814             ACPI_MASK_BITS_ABOVE(obj_desc->common_field.access_bit_width);
815         mask =
816             width_mask & ACPI_MASK_BITS_BELOW(obj_desc->common_field.
817                                               start_field_bit_offset);
818
819         datum_count = ACPI_ROUND_UP_TO(obj_desc->common_field.bit_length,
820                                        obj_desc->common_field.access_bit_width);
821
822         field_datum_count = ACPI_ROUND_UP_TO(obj_desc->common_field.bit_length +
823                                              obj_desc->common_field.
824                                              start_field_bit_offset,
825                                              obj_desc->common_field.
826                                              access_bit_width);
827
828         /* Get initial Datum from the input buffer */
829
830         ACPI_MEMCPY(&raw_datum, buffer,
831                     ACPI_MIN(obj_desc->common_field.access_byte_width,
832                              buffer_length - buffer_offset));
833
834         merged_datum =
835             raw_datum << obj_desc->common_field.start_field_bit_offset;
836
837         /* Write the entire field */
838
839         for (i = 1; i < field_datum_count; i++) {
840
841                 /* Write merged datum to the target field */
842
843                 merged_datum &= mask;
844                 status = acpi_ex_write_with_update_rule(obj_desc, mask,
845                                                         merged_datum,
846                                                         field_offset);
847                 if (ACPI_FAILURE(status)) {
848                         return_ACPI_STATUS(status);
849                 }
850
851                 /* Start new output datum by merging with previous input datum */
852
853                 field_offset += obj_desc->common_field.access_byte_width;
854                 merged_datum = raw_datum >>
855                     (obj_desc->common_field.access_bit_width -
856                      obj_desc->common_field.start_field_bit_offset);
857                 mask = width_mask;
858
859                 if (i == datum_count) {
860                         break;
861                 }
862
863                 /* Get the next input datum from the buffer */
864
865                 buffer_offset += obj_desc->common_field.access_byte_width;
866                 ACPI_MEMCPY(&raw_datum, ((char *)buffer) + buffer_offset,
867                             ACPI_MIN(obj_desc->common_field.access_byte_width,
868                                      buffer_length - buffer_offset));
869                 merged_datum |=
870                     raw_datum << obj_desc->common_field.start_field_bit_offset;
871         }
872
873         /* Mask off any extra bits in the last datum */
874
875         buffer_tail_bits = (obj_desc->common_field.bit_length +
876                             obj_desc->common_field.start_field_bit_offset) %
877             obj_desc->common_field.access_bit_width;
878         if (buffer_tail_bits) {
879                 mask &= ACPI_MASK_BITS_ABOVE(buffer_tail_bits);
880         }
881
882         /* Write the last datum to the field */
883
884         merged_datum &= mask;
885         status = acpi_ex_write_with_update_rule(obj_desc,
886                                                 mask, merged_datum,
887                                                 field_offset);
888
889         return_ACPI_STATUS(status);
890 }