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