ACPICA: hide private headers
[linux-2.6.git] / drivers / acpi / acpica / exfldio.c
1 /******************************************************************************
2  *
3  * Module Name: exfldio - Aml Field I/O
4  *
5  *****************************************************************************/
6
7 /*
8  * Copyright (C) 2000 - 2008, 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 #include <acpi/acpi.h>
45 #include "accommon.h"
46 #include "acinterp.h"
47 #include "amlcode.h"
48 #include "acevents.h"
49 #include "acdispat.h"
50
51 #define _COMPONENT          ACPI_EXECUTER
52 ACPI_MODULE_NAME("exfldio")
53
54 /* Local prototypes */
55 static acpi_status
56 acpi_ex_field_datum_io(union acpi_operand_object *obj_desc,
57                        u32 field_datum_byte_offset,
58                        acpi_integer * value, u32 read_write);
59
60 static u8
61 acpi_ex_register_overflow(union acpi_operand_object *obj_desc,
62                           acpi_integer value);
63
64 static acpi_status
65 acpi_ex_setup_region(union acpi_operand_object *obj_desc,
66                      u32 field_datum_byte_offset);
67
68 /*******************************************************************************
69  *
70  * FUNCTION:    acpi_ex_setup_region
71  *
72  * PARAMETERS:  obj_desc                - Field to be read or written
73  *              field_datum_byte_offset - Byte offset of this datum within the
74  *                                        parent field
75  *
76  * RETURN:      Status
77  *
78  * DESCRIPTION: Common processing for acpi_ex_extract_from_field and
79  *              acpi_ex_insert_into_field. Initialize the Region if necessary and
80  *              validate the request.
81  *
82  ******************************************************************************/
83
84 static acpi_status
85 acpi_ex_setup_region(union acpi_operand_object *obj_desc,
86                      u32 field_datum_byte_offset)
87 {
88         acpi_status status = AE_OK;
89         union acpi_operand_object *rgn_desc;
90
91         ACPI_FUNCTION_TRACE_U32(ex_setup_region, field_datum_byte_offset);
92
93         rgn_desc = obj_desc->common_field.region_obj;
94
95         /* We must have a valid region */
96
97         if (ACPI_GET_OBJECT_TYPE(rgn_desc) != ACPI_TYPE_REGION) {
98                 ACPI_ERROR((AE_INFO, "Needed Region, found type %X (%s)",
99                             ACPI_GET_OBJECT_TYPE(rgn_desc),
100                             acpi_ut_get_object_type_name(rgn_desc)));
101
102                 return_ACPI_STATUS(AE_AML_OPERAND_TYPE);
103         }
104
105         /*
106          * If the Region Address and Length have not been previously evaluated,
107          * evaluate them now and save the results.
108          */
109         if (!(rgn_desc->common.flags & AOPOBJ_DATA_VALID)) {
110                 status = acpi_ds_get_region_arguments(rgn_desc);
111                 if (ACPI_FAILURE(status)) {
112                         return_ACPI_STATUS(status);
113                 }
114         }
115
116         /* Exit if Address/Length have been disallowed by the host OS */
117
118         if (rgn_desc->common.flags & AOPOBJ_INVALID) {
119                 return_ACPI_STATUS(AE_AML_ILLEGAL_ADDRESS);
120         }
121
122         /*
123          * Exit now for SMBus address space, it has a non-linear address space
124          * and the request cannot be directly validated
125          */
126         if (rgn_desc->region.space_id == ACPI_ADR_SPACE_SMBUS) {
127
128                 /* SMBus has a non-linear address space */
129
130                 return_ACPI_STATUS(AE_OK);
131         }
132 #ifdef ACPI_UNDER_DEVELOPMENT
133         /*
134          * If the Field access is any_acc, we can now compute the optimal
135          * access (because we know know the length of the parent region)
136          */
137         if (!(obj_desc->common.flags & AOPOBJ_DATA_VALID)) {
138                 if (ACPI_FAILURE(status)) {
139                         return_ACPI_STATUS(status);
140                 }
141         }
142 #endif
143
144         /*
145          * Validate the request.  The entire request from the byte offset for a
146          * length of one field datum (access width) must fit within the region.
147          * (Region length is specified in bytes)
148          */
149         if (rgn_desc->region.length <
150             (obj_desc->common_field.base_byte_offset +
151              field_datum_byte_offset +
152              obj_desc->common_field.access_byte_width)) {
153                 if (acpi_gbl_enable_interpreter_slack) {
154                         /*
155                          * Slack mode only:  We will go ahead and allow access to this
156                          * field if it is within the region length rounded up to the next
157                          * access width boundary. acpi_size cast for 64-bit compile.
158                          */
159                         if (ACPI_ROUND_UP(rgn_desc->region.length,
160                                           obj_desc->common_field.
161                                           access_byte_width) >=
162                             ((acpi_size) obj_desc->common_field.
163                              base_byte_offset +
164                              obj_desc->common_field.access_byte_width +
165                              field_datum_byte_offset)) {
166                                 return_ACPI_STATUS(AE_OK);
167                         }
168                 }
169
170                 if (rgn_desc->region.length <
171                     obj_desc->common_field.access_byte_width) {
172                         /*
173                          * This is the case where the access_type (acc_word, etc.) is wider
174                          * than the region itself.  For example, a region of length one
175                          * byte, and a field with Dword access specified.
176                          */
177                         ACPI_ERROR((AE_INFO,
178                                     "Field [%4.4s] access width (%d bytes) too large for region [%4.4s] (length %X)",
179                                     acpi_ut_get_node_name(obj_desc->
180                                                           common_field.node),
181                                     obj_desc->common_field.access_byte_width,
182                                     acpi_ut_get_node_name(rgn_desc->region.
183                                                           node),
184                                     rgn_desc->region.length));
185                 }
186
187                 /*
188                  * Offset rounded up to next multiple of field width
189                  * exceeds region length, indicate an error
190                  */
191                 ACPI_ERROR((AE_INFO,
192                             "Field [%4.4s] Base+Offset+Width %X+%X+%X is beyond end of region [%4.4s] (length %X)",
193                             acpi_ut_get_node_name(obj_desc->common_field.node),
194                             obj_desc->common_field.base_byte_offset,
195                             field_datum_byte_offset,
196                             obj_desc->common_field.access_byte_width,
197                             acpi_ut_get_node_name(rgn_desc->region.node),
198                             rgn_desc->region.length));
199
200                 return_ACPI_STATUS(AE_AML_REGION_LIMIT);
201         }
202
203         return_ACPI_STATUS(AE_OK);
204 }
205
206 /*******************************************************************************
207  *
208  * FUNCTION:    acpi_ex_access_region
209  *
210  * PARAMETERS:  obj_desc                - Field to be read
211  *              field_datum_byte_offset - Byte offset of this datum within the
212  *                                        parent field
213  *              Value                   - Where to store value (must at least
214  *                                        the size of acpi_integer)
215  *              Function                - Read or Write flag plus other region-
216  *                                        dependent flags
217  *
218  * RETURN:      Status
219  *
220  * DESCRIPTION: Read or Write a single field datum to an Operation Region.
221  *
222  ******************************************************************************/
223
224 acpi_status
225 acpi_ex_access_region(union acpi_operand_object *obj_desc,
226                       u32 field_datum_byte_offset,
227                       acpi_integer * value, u32 function)
228 {
229         acpi_status status;
230         union acpi_operand_object *rgn_desc;
231         acpi_physical_address address;
232
233         ACPI_FUNCTION_TRACE(ex_access_region);
234
235         /*
236          * Ensure that the region operands are fully evaluated and verify
237          * the validity of the request
238          */
239         status = acpi_ex_setup_region(obj_desc, field_datum_byte_offset);
240         if (ACPI_FAILURE(status)) {
241                 return_ACPI_STATUS(status);
242         }
243
244         /*
245          * The physical address of this field datum is:
246          *
247          * 1) The base of the region, plus
248          * 2) The base offset of the field, plus
249          * 3) The current offset into the field
250          */
251         rgn_desc = obj_desc->common_field.region_obj;
252         address = rgn_desc->region.address +
253             obj_desc->common_field.base_byte_offset + field_datum_byte_offset;
254
255         if ((function & ACPI_IO_MASK) == ACPI_READ) {
256                 ACPI_DEBUG_PRINT((ACPI_DB_BFIELD, "[READ]"));
257         } else {
258                 ACPI_DEBUG_PRINT((ACPI_DB_BFIELD, "[WRITE]"));
259         }
260
261         ACPI_DEBUG_PRINT_RAW((ACPI_DB_BFIELD,
262                               " Region [%s:%X], Width %X, ByteBase %X, Offset %X at %p\n",
263                               acpi_ut_get_region_name(rgn_desc->region.
264                                                       space_id),
265                               rgn_desc->region.space_id,
266                               obj_desc->common_field.access_byte_width,
267                               obj_desc->common_field.base_byte_offset,
268                               field_datum_byte_offset, ACPI_CAST_PTR(void,
269                                                                      address)));
270
271         /* Invoke the appropriate address_space/op_region handler */
272
273         status = acpi_ev_address_space_dispatch(rgn_desc, function,
274                                                 address,
275                                                 ACPI_MUL_8(obj_desc->
276                                                            common_field.
277                                                            access_byte_width),
278                                                 value);
279
280         if (ACPI_FAILURE(status)) {
281                 if (status == AE_NOT_IMPLEMENTED) {
282                         ACPI_ERROR((AE_INFO,
283                                     "Region %s(%X) not implemented",
284                                     acpi_ut_get_region_name(rgn_desc->region.
285                                                             space_id),
286                                     rgn_desc->region.space_id));
287                 } else if (status == AE_NOT_EXIST) {
288                         ACPI_ERROR((AE_INFO,
289                                     "Region %s(%X) has no handler",
290                                     acpi_ut_get_region_name(rgn_desc->region.
291                                                             space_id),
292                                     rgn_desc->region.space_id));
293                 }
294         }
295
296         return_ACPI_STATUS(status);
297 }
298
299 /*******************************************************************************
300  *
301  * FUNCTION:    acpi_ex_register_overflow
302  *
303  * PARAMETERS:  obj_desc                - Register(Field) to be written
304  *              Value                   - Value to be stored
305  *
306  * RETURN:      TRUE if value overflows the field, FALSE otherwise
307  *
308  * DESCRIPTION: Check if a value is out of range of the field being written.
309  *              Used to check if the values written to Index and Bank registers
310  *              are out of range.  Normally, the value is simply truncated
311  *              to fit the field, but this case is most likely a serious
312  *              coding error in the ASL.
313  *
314  ******************************************************************************/
315
316 static u8
317 acpi_ex_register_overflow(union acpi_operand_object *obj_desc,
318                           acpi_integer value)
319 {
320
321         if (obj_desc->common_field.bit_length >= ACPI_INTEGER_BIT_SIZE) {
322                 /*
323                  * The field is large enough to hold the maximum integer, so we can
324                  * never overflow it.
325                  */
326                 return (FALSE);
327         }
328
329         if (value >= ((acpi_integer) 1 << obj_desc->common_field.bit_length)) {
330                 /*
331                  * The Value is larger than the maximum value that can fit into
332                  * the register.
333                  */
334                 return (TRUE);
335         }
336
337         /* The Value will fit into the field with no truncation */
338
339         return (FALSE);
340 }
341
342 /*******************************************************************************
343  *
344  * FUNCTION:    acpi_ex_field_datum_io
345  *
346  * PARAMETERS:  obj_desc                - Field to be read
347  *              field_datum_byte_offset - Byte offset of this datum within the
348  *                                        parent field
349  *              Value                   - Where to store value (must be 64 bits)
350  *              read_write              - Read or Write flag
351  *
352  * RETURN:      Status
353  *
354  * DESCRIPTION: Read or Write a single datum of a field.  The field_type is
355  *              demultiplexed here to handle the different types of fields
356  *              (buffer_field, region_field, index_field, bank_field)
357  *
358  ******************************************************************************/
359
360 static acpi_status
361 acpi_ex_field_datum_io(union acpi_operand_object *obj_desc,
362                        u32 field_datum_byte_offset,
363                        acpi_integer * value, u32 read_write)
364 {
365         acpi_status status;
366         acpi_integer local_value;
367
368         ACPI_FUNCTION_TRACE_U32(ex_field_datum_io, field_datum_byte_offset);
369
370         if (read_write == ACPI_READ) {
371                 if (!value) {
372                         local_value = 0;
373
374                         /* To support reads without saving return value */
375                         value = &local_value;
376                 }
377
378                 /* Clear the entire return buffer first, [Very Important!] */
379
380                 *value = 0;
381         }
382
383         /*
384          * The four types of fields are:
385          *
386          * buffer_field - Read/write from/to a Buffer
387          * region_field - Read/write from/to a Operation Region.
388          * bank_field  - Write to a Bank Register, then read/write from/to an
389          *               operation_region
390          * index_field - Write to an Index Register, then read/write from/to a
391          *               Data Register
392          */
393         switch (ACPI_GET_OBJECT_TYPE(obj_desc)) {
394         case ACPI_TYPE_BUFFER_FIELD:
395                 /*
396                  * If the buffer_field arguments have not been previously evaluated,
397                  * evaluate them now and save the results.
398                  */
399                 if (!(obj_desc->common.flags & AOPOBJ_DATA_VALID)) {
400                         status = acpi_ds_get_buffer_field_arguments(obj_desc);
401                         if (ACPI_FAILURE(status)) {
402                                 return_ACPI_STATUS(status);
403                         }
404                 }
405
406                 if (read_write == ACPI_READ) {
407                         /*
408                          * Copy the data from the source buffer.
409                          * Length is the field width in bytes.
410                          */
411                         ACPI_MEMCPY(value,
412                                     (obj_desc->buffer_field.buffer_obj)->buffer.
413                                     pointer +
414                                     obj_desc->buffer_field.base_byte_offset +
415                                     field_datum_byte_offset,
416                                     obj_desc->common_field.access_byte_width);
417                 } else {
418                         /*
419                          * Copy the data to the target buffer.
420                          * Length is the field width in bytes.
421                          */
422                         ACPI_MEMCPY((obj_desc->buffer_field.buffer_obj)->buffer.
423                                     pointer +
424                                     obj_desc->buffer_field.base_byte_offset +
425                                     field_datum_byte_offset, value,
426                                     obj_desc->common_field.access_byte_width);
427                 }
428
429                 status = AE_OK;
430                 break;
431
432         case ACPI_TYPE_LOCAL_BANK_FIELD:
433
434                 /*
435                  * Ensure that the bank_value is not beyond the capacity of
436                  * the register
437                  */
438                 if (acpi_ex_register_overflow(obj_desc->bank_field.bank_obj,
439                                               (acpi_integer) obj_desc->
440                                               bank_field.value)) {
441                         return_ACPI_STATUS(AE_AML_REGISTER_LIMIT);
442                 }
443
444                 /*
445                  * For bank_fields, we must write the bank_value to the bank_register
446                  * (itself a region_field) before we can access the data.
447                  */
448                 status =
449                     acpi_ex_insert_into_field(obj_desc->bank_field.bank_obj,
450                                               &obj_desc->bank_field.value,
451                                               sizeof(obj_desc->bank_field.
452                                                      value));
453                 if (ACPI_FAILURE(status)) {
454                         return_ACPI_STATUS(status);
455                 }
456
457                 /*
458                  * Now that the Bank has been selected, fall through to the
459                  * region_field case and write the datum to the Operation Region
460                  */
461
462                 /*lint -fallthrough */
463
464         case ACPI_TYPE_LOCAL_REGION_FIELD:
465                 /*
466                  * For simple region_fields, we just directly access the owning
467                  * Operation Region.
468                  */
469                 status =
470                     acpi_ex_access_region(obj_desc, field_datum_byte_offset,
471                                           value, read_write);
472                 break;
473
474         case ACPI_TYPE_LOCAL_INDEX_FIELD:
475
476                 /*
477                  * Ensure that the index_value is not beyond the capacity of
478                  * the register
479                  */
480                 if (acpi_ex_register_overflow(obj_desc->index_field.index_obj,
481                                               (acpi_integer) obj_desc->
482                                               index_field.value)) {
483                         return_ACPI_STATUS(AE_AML_REGISTER_LIMIT);
484                 }
485
486                 /* Write the index value to the index_register (itself a region_field) */
487
488                 field_datum_byte_offset += obj_desc->index_field.value;
489
490                 ACPI_DEBUG_PRINT((ACPI_DB_BFIELD,
491                                   "Write to Index Register: Value %8.8X\n",
492                                   field_datum_byte_offset));
493
494                 status =
495                     acpi_ex_insert_into_field(obj_desc->index_field.index_obj,
496                                               &field_datum_byte_offset,
497                                               sizeof(field_datum_byte_offset));
498                 if (ACPI_FAILURE(status)) {
499                         return_ACPI_STATUS(status);
500                 }
501
502                 if (read_write == ACPI_READ) {
503
504                         /* Read the datum from the data_register */
505
506                         ACPI_DEBUG_PRINT((ACPI_DB_BFIELD,
507                                           "Read from Data Register\n"));
508
509                         status =
510                             acpi_ex_extract_from_field(obj_desc->index_field.
511                                                        data_obj, value,
512                                                        sizeof(acpi_integer));
513                 } else {
514                         /* Write the datum to the data_register */
515
516                         ACPI_DEBUG_PRINT((ACPI_DB_BFIELD,
517                                           "Write to Data Register: Value %8.8X%8.8X\n",
518                                           ACPI_FORMAT_UINT64(*value)));
519
520                         status =
521                             acpi_ex_insert_into_field(obj_desc->index_field.
522                                                       data_obj, value,
523                                                       sizeof(acpi_integer));
524                 }
525                 break;
526
527         default:
528
529                 ACPI_ERROR((AE_INFO, "Wrong object type in field I/O %X",
530                             ACPI_GET_OBJECT_TYPE(obj_desc)));
531                 status = AE_AML_INTERNAL;
532                 break;
533         }
534
535         if (ACPI_SUCCESS(status)) {
536                 if (read_write == ACPI_READ) {
537                         ACPI_DEBUG_PRINT((ACPI_DB_BFIELD,
538                                           "Value Read %8.8X%8.8X, Width %d\n",
539                                           ACPI_FORMAT_UINT64(*value),
540                                           obj_desc->common_field.
541                                           access_byte_width));
542                 } else {
543                         ACPI_DEBUG_PRINT((ACPI_DB_BFIELD,
544                                           "Value Written %8.8X%8.8X, Width %d\n",
545                                           ACPI_FORMAT_UINT64(*value),
546                                           obj_desc->common_field.
547                                           access_byte_width));
548                 }
549         }
550
551         return_ACPI_STATUS(status);
552 }
553
554 /*******************************************************************************
555  *
556  * FUNCTION:    acpi_ex_write_with_update_rule
557  *
558  * PARAMETERS:  obj_desc                - Field to be written
559  *              Mask                    - bitmask within field datum
560  *              field_value             - Value to write
561  *              field_datum_byte_offset - Offset of datum within field
562  *
563  * RETURN:      Status
564  *
565  * DESCRIPTION: Apply the field update rule to a field write
566  *
567  ******************************************************************************/
568
569 acpi_status
570 acpi_ex_write_with_update_rule(union acpi_operand_object *obj_desc,
571                                acpi_integer mask,
572                                acpi_integer field_value,
573                                u32 field_datum_byte_offset)
574 {
575         acpi_status status = AE_OK;
576         acpi_integer merged_value;
577         acpi_integer current_value;
578
579         ACPI_FUNCTION_TRACE_U32(ex_write_with_update_rule, mask);
580
581         /* Start with the new bits  */
582
583         merged_value = field_value;
584
585         /* If the mask is all ones, we don't need to worry about the update rule */
586
587         if (mask != ACPI_INTEGER_MAX) {
588
589                 /* Decode the update rule */
590
591                 switch (obj_desc->common_field.
592                         field_flags & AML_FIELD_UPDATE_RULE_MASK) {
593                 case AML_FIELD_UPDATE_PRESERVE:
594                         /*
595                          * Check if update rule needs to be applied (not if mask is all
596                          * ones)  The left shift drops the bits we want to ignore.
597                          */
598                         if ((~mask << (ACPI_MUL_8(sizeof(mask)) -
599                                        ACPI_MUL_8(obj_desc->common_field.
600                                                   access_byte_width))) != 0) {
601                                 /*
602                                  * Read the current contents of the byte/word/dword containing
603                                  * the field, and merge with the new field value.
604                                  */
605                                 status =
606                                     acpi_ex_field_datum_io(obj_desc,
607                                                            field_datum_byte_offset,
608                                                            &current_value,
609                                                            ACPI_READ);
610                                 if (ACPI_FAILURE(status)) {
611                                         return_ACPI_STATUS(status);
612                                 }
613
614                                 merged_value |= (current_value & ~mask);
615                         }
616                         break;
617
618                 case AML_FIELD_UPDATE_WRITE_AS_ONES:
619
620                         /* Set positions outside the field to all ones */
621
622                         merged_value |= ~mask;
623                         break;
624
625                 case AML_FIELD_UPDATE_WRITE_AS_ZEROS:
626
627                         /* Set positions outside the field to all zeros */
628
629                         merged_value &= mask;
630                         break;
631
632                 default:
633
634                         ACPI_ERROR((AE_INFO,
635                                     "Unknown UpdateRule value: %X",
636                                     (obj_desc->common_field.
637                                      field_flags &
638                                      AML_FIELD_UPDATE_RULE_MASK)));
639                         return_ACPI_STATUS(AE_AML_OPERAND_VALUE);
640                 }
641         }
642
643         ACPI_DEBUG_PRINT((ACPI_DB_BFIELD,
644                           "Mask %8.8X%8.8X, DatumOffset %X, Width %X, Value %8.8X%8.8X, MergedValue %8.8X%8.8X\n",
645                           ACPI_FORMAT_UINT64(mask),
646                           field_datum_byte_offset,
647                           obj_desc->common_field.access_byte_width,
648                           ACPI_FORMAT_UINT64(field_value),
649                           ACPI_FORMAT_UINT64(merged_value)));
650
651         /* Write the merged value */
652
653         status = acpi_ex_field_datum_io(obj_desc, field_datum_byte_offset,
654                                         &merged_value, ACPI_WRITE);
655
656         return_ACPI_STATUS(status);
657 }
658
659 /*******************************************************************************
660  *
661  * FUNCTION:    acpi_ex_extract_from_field
662  *
663  * PARAMETERS:  obj_desc            - Field to be read
664  *              Buffer              - Where to store the field data
665  *              buffer_length       - Length of Buffer
666  *
667  * RETURN:      Status
668  *
669  * DESCRIPTION: Retrieve the current value of the given field
670  *
671  ******************************************************************************/
672
673 acpi_status
674 acpi_ex_extract_from_field(union acpi_operand_object *obj_desc,
675                            void *buffer, u32 buffer_length)
676 {
677         acpi_status status;
678         acpi_integer raw_datum;
679         acpi_integer merged_datum;
680         u32 field_offset = 0;
681         u32 buffer_offset = 0;
682         u32 buffer_tail_bits;
683         u32 datum_count;
684         u32 field_datum_count;
685         u32 i;
686
687         ACPI_FUNCTION_TRACE(ex_extract_from_field);
688
689         /* Validate target buffer and clear it */
690
691         if (buffer_length <
692             ACPI_ROUND_BITS_UP_TO_BYTES(obj_desc->common_field.bit_length)) {
693                 ACPI_ERROR((AE_INFO,
694                             "Field size %X (bits) is too large for buffer (%X)",
695                             obj_desc->common_field.bit_length, buffer_length));
696
697                 return_ACPI_STATUS(AE_BUFFER_OVERFLOW);
698         }
699         ACPI_MEMSET(buffer, 0, buffer_length);
700
701         /* Compute the number of datums (access width data items) */
702
703         datum_count = ACPI_ROUND_UP_TO(obj_desc->common_field.bit_length,
704                                        obj_desc->common_field.access_bit_width);
705         field_datum_count = ACPI_ROUND_UP_TO(obj_desc->common_field.bit_length +
706                                              obj_desc->common_field.
707                                              start_field_bit_offset,
708                                              obj_desc->common_field.
709                                              access_bit_width);
710
711         /* Priming read from the field */
712
713         status =
714             acpi_ex_field_datum_io(obj_desc, field_offset, &raw_datum,
715                                    ACPI_READ);
716         if (ACPI_FAILURE(status)) {
717                 return_ACPI_STATUS(status);
718         }
719         merged_datum =
720             raw_datum >> obj_desc->common_field.start_field_bit_offset;
721
722         /* Read the rest of the field */
723
724         for (i = 1; i < field_datum_count; i++) {
725
726                 /* Get next input datum from the field */
727
728                 field_offset += obj_desc->common_field.access_byte_width;
729                 status = acpi_ex_field_datum_io(obj_desc, field_offset,
730                                                 &raw_datum, ACPI_READ);
731                 if (ACPI_FAILURE(status)) {
732                         return_ACPI_STATUS(status);
733                 }
734
735                 /*
736                  * Merge with previous datum if necessary.
737                  *
738                  * Note: Before the shift, check if the shift value will be larger than
739                  * the integer size. If so, there is no need to perform the operation.
740                  * This avoids the differences in behavior between different compilers
741                  * concerning shift values larger than the target data width.
742                  */
743                 if ((obj_desc->common_field.access_bit_width -
744                      obj_desc->common_field.start_field_bit_offset) <
745                     ACPI_INTEGER_BIT_SIZE) {
746                         merged_datum |=
747                             raw_datum << (obj_desc->common_field.
748                                           access_bit_width -
749                                           obj_desc->common_field.
750                                           start_field_bit_offset);
751                 }
752
753                 if (i == datum_count) {
754                         break;
755                 }
756
757                 /* Write merged datum to target buffer */
758
759                 ACPI_MEMCPY(((char *)buffer) + buffer_offset, &merged_datum,
760                             ACPI_MIN(obj_desc->common_field.access_byte_width,
761                                      buffer_length - buffer_offset));
762
763                 buffer_offset += obj_desc->common_field.access_byte_width;
764                 merged_datum =
765                     raw_datum >> obj_desc->common_field.start_field_bit_offset;
766         }
767
768         /* Mask off any extra bits in the last datum */
769
770         buffer_tail_bits = obj_desc->common_field.bit_length %
771             obj_desc->common_field.access_bit_width;
772         if (buffer_tail_bits) {
773                 merged_datum &= ACPI_MASK_BITS_ABOVE(buffer_tail_bits);
774         }
775
776         /* Write the last datum to the buffer */
777
778         ACPI_MEMCPY(((char *)buffer) + buffer_offset, &merged_datum,
779                     ACPI_MIN(obj_desc->common_field.access_byte_width,
780                              buffer_length - buffer_offset));
781
782         return_ACPI_STATUS(AE_OK);
783 }
784
785 /*******************************************************************************
786  *
787  * FUNCTION:    acpi_ex_insert_into_field
788  *
789  * PARAMETERS:  obj_desc            - Field to be written
790  *              Buffer              - Data to be written
791  *              buffer_length       - Length of Buffer
792  *
793  * RETURN:      Status
794  *
795  * DESCRIPTION: Store the Buffer contents into the given field
796  *
797  ******************************************************************************/
798
799 acpi_status
800 acpi_ex_insert_into_field(union acpi_operand_object *obj_desc,
801                           void *buffer, u32 buffer_length)
802 {
803         acpi_status status;
804         acpi_integer mask;
805         acpi_integer width_mask;
806         acpi_integer merged_datum;
807         acpi_integer raw_datum = 0;
808         u32 field_offset = 0;
809         u32 buffer_offset = 0;
810         u32 buffer_tail_bits;
811         u32 datum_count;
812         u32 field_datum_count;
813         u32 i;
814         u32 required_length;
815         void *new_buffer;
816
817         ACPI_FUNCTION_TRACE(ex_insert_into_field);
818
819         /* Validate input buffer */
820
821         new_buffer = NULL;
822         required_length =
823             ACPI_ROUND_BITS_UP_TO_BYTES(obj_desc->common_field.bit_length);
824         /*
825          * We must have a buffer that is at least as long as the field
826          * we are writing to.  This is because individual fields are
827          * indivisible and partial writes are not supported -- as per
828          * the ACPI specification.
829          */
830         if (buffer_length < required_length) {
831
832                 /* We need to create a new buffer */
833
834                 new_buffer = ACPI_ALLOCATE_ZEROED(required_length);
835                 if (!new_buffer) {
836                         return_ACPI_STATUS(AE_NO_MEMORY);
837                 }
838
839                 /*
840                  * Copy the original data to the new buffer, starting
841                  * at Byte zero.  All unused (upper) bytes of the
842                  * buffer will be 0.
843                  */
844                 ACPI_MEMCPY((char *)new_buffer, (char *)buffer, buffer_length);
845                 buffer = new_buffer;
846                 buffer_length = required_length;
847         }
848
849         /*
850          * Create the bitmasks used for bit insertion.
851          * Note: This if/else is used to bypass compiler differences with the
852          * shift operator
853          */
854         if (obj_desc->common_field.access_bit_width == ACPI_INTEGER_BIT_SIZE) {
855                 width_mask = ACPI_INTEGER_MAX;
856         } else {
857                 width_mask =
858                     ACPI_MASK_BITS_ABOVE(obj_desc->common_field.
859                                          access_bit_width);
860         }
861
862         mask = width_mask &
863             ACPI_MASK_BITS_BELOW(obj_desc->common_field.start_field_bit_offset);
864
865         /* Compute the number of datums (access width data items) */
866
867         datum_count = ACPI_ROUND_UP_TO(obj_desc->common_field.bit_length,
868                                        obj_desc->common_field.access_bit_width);
869
870         field_datum_count = ACPI_ROUND_UP_TO(obj_desc->common_field.bit_length +
871                                              obj_desc->common_field.
872                                              start_field_bit_offset,
873                                              obj_desc->common_field.
874                                              access_bit_width);
875
876         /* Get initial Datum from the input buffer */
877
878         ACPI_MEMCPY(&raw_datum, buffer,
879                     ACPI_MIN(obj_desc->common_field.access_byte_width,
880                              buffer_length - buffer_offset));
881
882         merged_datum =
883             raw_datum << obj_desc->common_field.start_field_bit_offset;
884
885         /* Write the entire field */
886
887         for (i = 1; i < field_datum_count; i++) {
888
889                 /* Write merged datum to the target field */
890
891                 merged_datum &= mask;
892                 status = acpi_ex_write_with_update_rule(obj_desc, mask,
893                                                         merged_datum,
894                                                         field_offset);
895                 if (ACPI_FAILURE(status)) {
896                         goto exit;
897                 }
898
899                 field_offset += obj_desc->common_field.access_byte_width;
900
901                 /*
902                  * Start new output datum by merging with previous input datum
903                  * if necessary.
904                  *
905                  * Note: Before the shift, check if the shift value will be larger than
906                  * the integer size. If so, there is no need to perform the operation.
907                  * This avoids the differences in behavior between different compilers
908                  * concerning shift values larger than the target data width.
909                  */
910                 if ((obj_desc->common_field.access_bit_width -
911                      obj_desc->common_field.start_field_bit_offset) <
912                     ACPI_INTEGER_BIT_SIZE) {
913                         merged_datum =
914                             raw_datum >> (obj_desc->common_field.
915                                           access_bit_width -
916                                           obj_desc->common_field.
917                                           start_field_bit_offset);
918                 } else {
919                         merged_datum = 0;
920                 }
921
922                 mask = width_mask;
923
924                 if (i == datum_count) {
925                         break;
926                 }
927
928                 /* Get the next input datum from the buffer */
929
930                 buffer_offset += obj_desc->common_field.access_byte_width;
931                 ACPI_MEMCPY(&raw_datum, ((char *)buffer) + buffer_offset,
932                             ACPI_MIN(obj_desc->common_field.access_byte_width,
933                                      buffer_length - buffer_offset));
934                 merged_datum |=
935                     raw_datum << obj_desc->common_field.start_field_bit_offset;
936         }
937
938         /* Mask off any extra bits in the last datum */
939
940         buffer_tail_bits = (obj_desc->common_field.bit_length +
941                             obj_desc->common_field.start_field_bit_offset) %
942             obj_desc->common_field.access_bit_width;
943         if (buffer_tail_bits) {
944                 mask &= ACPI_MASK_BITS_ABOVE(buffer_tail_bits);
945         }
946
947         /* Write the last datum to the field */
948
949         merged_datum &= mask;
950         status = acpi_ex_write_with_update_rule(obj_desc,
951                                                 mask, merged_datum,
952                                                 field_offset);
953
954       exit:
955         /* Free temporary buffer if we used one */
956
957         if (new_buffer) {
958                 ACPI_FREE(new_buffer);
959         }
960         return_ACPI_STATUS(status);
961 }