1// SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0
2/******************************************************************************
3 *
4 * Module Name: exfldio - Aml Field I/O
5 *
6 * Copyright (C) 2000 - 2025, Intel Corp.
7 *
8 *****************************************************************************/
9
10#include <acpi/acpi.h>
11#include "accommon.h"
12#include "acinterp.h"
13#include "amlcode.h"
14#include "acevents.h"
15#include "acdispat.h"
16
17#define _COMPONENT ACPI_EXECUTER
18ACPI_MODULE_NAME("exfldio")
19
20/* Local prototypes */
21static acpi_status
22acpi_ex_field_datum_io(union acpi_operand_object *obj_desc,
23 u32 field_datum_byte_offset, u64 *value, u32 read_write);
24
25static u8
26acpi_ex_register_overflow(union acpi_operand_object *obj_desc, u64 value);
27
28static acpi_status
29acpi_ex_setup_region(union acpi_operand_object *obj_desc,
30 u32 field_datum_byte_offset);
31
32/*******************************************************************************
33 *
34 * FUNCTION: acpi_ex_setup_region
35 *
36 * PARAMETERS: obj_desc - Field to be read or written
37 * field_datum_byte_offset - Byte offset of this datum within the
38 * parent field
39 *
40 * RETURN: Status
41 *
42 * DESCRIPTION: Common processing for acpi_ex_extract_from_field and
43 * acpi_ex_insert_into_field. Initialize the Region if necessary and
44 * validate the request.
45 *
46 ******************************************************************************/
47
48static acpi_status
49acpi_ex_setup_region(union acpi_operand_object *obj_desc,
50 u32 field_datum_byte_offset)
51{
52 acpi_status status = AE_OK;
53 union acpi_operand_object *rgn_desc;
54 u8 space_id;
55
56 ACPI_FUNCTION_TRACE_U32(ex_setup_region, field_datum_byte_offset);
57
58 rgn_desc = obj_desc->common_field.region_obj;
59
60 /* We must have a valid region */
61
62 if (rgn_desc->common.type != ACPI_TYPE_REGION) {
63 ACPI_ERROR((AE_INFO, "Needed Region, found type 0x%X (%s)",
64 rgn_desc->common.type,
65 acpi_ut_get_object_type_name(rgn_desc)));
66
67 return_ACPI_STATUS(AE_AML_OPERAND_TYPE);
68 }
69
70 space_id = rgn_desc->region.space_id;
71
72 /* Validate the Space ID */
73
74 if (!acpi_is_valid_space_id(space_id)) {
75 ACPI_ERROR((AE_INFO,
76 "Invalid/unknown Address Space ID: 0x%2.2X",
77 space_id));
78 return_ACPI_STATUS(AE_AML_INVALID_SPACE_ID);
79 }
80
81 /*
82 * If the Region Address and Length have not been previously evaluated,
83 * evaluate them now and save the results.
84 */
85 if (!(rgn_desc->common.flags & AOPOBJ_DATA_VALID)) {
86 status = acpi_ds_get_region_arguments(rgn_desc);
87 if (ACPI_FAILURE(status)) {
88 return_ACPI_STATUS(status);
89 }
90 }
91
92 /*
93 * Exit now for SMBus, GSBus or IPMI address space, it has a non-linear
94 * address space and the request cannot be directly validated
95 */
96 if (space_id == ACPI_ADR_SPACE_SMBUS ||
97 space_id == ACPI_ADR_SPACE_GSBUS ||
98 space_id == ACPI_ADR_SPACE_IPMI) {
99
100 /* SMBus or IPMI has a non-linear address space */
101
102 return_ACPI_STATUS(AE_OK);
103 }
104#ifdef ACPI_UNDER_DEVELOPMENT
105 /*
106 * If the Field access is any_acc, we can now compute the optimal
107 * access (because we know the length of the parent region)
108 */
109 if (!(obj_desc->common.flags & AOPOBJ_DATA_VALID)) {
110 if (ACPI_FAILURE(status)) {
111 return_ACPI_STATUS(status);
112 }
113 }
114#endif
115
116 /*
117 * Validate the request. The entire request from the byte offset for a
118 * length of one field datum (access width) must fit within the region.
119 * (Region length is specified in bytes)
120 */
121 if (rgn_desc->region.length <
122 (obj_desc->common_field.base_byte_offset + field_datum_byte_offset +
123 obj_desc->common_field.access_byte_width)) {
124 if (acpi_gbl_enable_interpreter_slack) {
125 /*
126 * Slack mode only: We will go ahead and allow access to this
127 * field if it is within the region length rounded up to the next
128 * access width boundary. acpi_size cast for 64-bit compile.
129 */
130 if (ACPI_ROUND_UP(rgn_desc->region.length,
131 obj_desc->common_field.
132 access_byte_width) >=
133 ((acpi_size)obj_desc->common_field.
134 base_byte_offset +
135 obj_desc->common_field.access_byte_width +
136 field_datum_byte_offset)) {
137 return_ACPI_STATUS(AE_OK);
138 }
139 }
140
141 if (rgn_desc->region.length <
142 obj_desc->common_field.access_byte_width) {
143 /*
144 * This is the case where the access_type (acc_word, etc.) is wider
145 * than the region itself. For example, a region of length one
146 * byte, and a field with Dword access specified.
147 */
148 ACPI_ERROR((AE_INFO,
149 "Field [%4.4s] access width (%u bytes) "
150 "too large for region [%4.4s] (length %u)",
151 acpi_ut_get_node_name(obj_desc->
152 common_field.node),
153 obj_desc->common_field.access_byte_width,
154 acpi_ut_get_node_name(rgn_desc->region.
155 node),
156 rgn_desc->region.length));
157 }
158
159 /*
160 * Offset rounded up to next multiple of field width
161 * exceeds region length, indicate an error
162 */
163 ACPI_ERROR((AE_INFO,
164 "Field [%4.4s] Base+Offset+Width %u+%u+%u "
165 "is beyond end of region [%4.4s] (length %u)",
166 acpi_ut_get_node_name(obj_desc->common_field.node),
167 obj_desc->common_field.base_byte_offset,
168 field_datum_byte_offset,
169 obj_desc->common_field.access_byte_width,
170 acpi_ut_get_node_name(rgn_desc->region.node),
171 rgn_desc->region.length));
172
173 return_ACPI_STATUS(AE_AML_REGION_LIMIT);
174 }
175
176 return_ACPI_STATUS(AE_OK);
177}
178
179/*******************************************************************************
180 *
181 * FUNCTION: acpi_ex_access_region
182 *
183 * PARAMETERS: obj_desc - Field to be read
184 * field_datum_byte_offset - Byte offset of this datum within the
185 * parent field
186 * value - Where to store value (must at least
187 * 64 bits)
188 * function - Read or Write flag plus other region-
189 * dependent flags
190 *
191 * RETURN: Status
192 *
193 * DESCRIPTION: Read or Write a single field datum to an Operation Region.
194 *
195 ******************************************************************************/
196
197acpi_status
198acpi_ex_access_region(union acpi_operand_object *obj_desc,
199 u32 field_datum_byte_offset, u64 *value, u32 function)
200{
201 acpi_status status;
202 union acpi_operand_object *rgn_desc;
203 u32 region_offset;
204
205 ACPI_FUNCTION_TRACE(ex_access_region);
206
207 /*
208 * Ensure that the region operands are fully evaluated and verify
209 * the validity of the request
210 */
211 status = acpi_ex_setup_region(obj_desc, field_datum_byte_offset);
212 if (ACPI_FAILURE(status)) {
213 return_ACPI_STATUS(status);
214 }
215
216 /*
217 * The physical address of this field datum is:
218 *
219 * 1) The base of the region, plus
220 * 2) The base offset of the field, plus
221 * 3) The current offset into the field
222 */
223 rgn_desc = obj_desc->common_field.region_obj;
224 region_offset =
225 obj_desc->common_field.base_byte_offset + field_datum_byte_offset;
226
227 if ((function & ACPI_IO_MASK) == ACPI_READ) {
228 ACPI_DEBUG_PRINT((ACPI_DB_BFIELD, "[READ]"));
229 } else {
230 ACPI_DEBUG_PRINT((ACPI_DB_BFIELD, "[WRITE]"));
231 }
232
233 ACPI_DEBUG_PRINT_RAW((ACPI_DB_BFIELD,
234 " Region [%s:%X], Width %X, ByteBase %X, Offset %X at %8.8X%8.8X\n",
235 acpi_ut_get_region_name(rgn_desc->region.
236 space_id),
237 rgn_desc->region.space_id,
238 obj_desc->common_field.access_byte_width,
239 obj_desc->common_field.base_byte_offset,
240 field_datum_byte_offset,
241 ACPI_FORMAT_UINT64(rgn_desc->region.address +
242 region_offset)));
243
244 /* Invoke the appropriate address_space/op_region handler */
245
246 status = acpi_ev_address_space_dispatch(region_obj: rgn_desc, field_obj: obj_desc,
247 function, region_offset,
248 ACPI_MUL_8(obj_desc->
249 common_field.
250 access_byte_width),
251 value);
252
253 if (ACPI_FAILURE(status)) {
254 if (status == AE_NOT_IMPLEMENTED) {
255 ACPI_ERROR((AE_INFO,
256 "Region %s (ID=%u) not implemented",
257 acpi_ut_get_region_name(rgn_desc->region.
258 space_id),
259 rgn_desc->region.space_id));
260 } else if (status == AE_NOT_EXIST) {
261 ACPI_ERROR((AE_INFO,
262 "Region %s (ID=%u) has no handler",
263 acpi_ut_get_region_name(rgn_desc->region.
264 space_id),
265 rgn_desc->region.space_id));
266 }
267 }
268
269 return_ACPI_STATUS(status);
270}
271
272/*******************************************************************************
273 *
274 * FUNCTION: acpi_ex_register_overflow
275 *
276 * PARAMETERS: obj_desc - Register(Field) to be written
277 * value - Value to be stored
278 *
279 * RETURN: TRUE if value overflows the field, FALSE otherwise
280 *
281 * DESCRIPTION: Check if a value is out of range of the field being written.
282 * Used to check if the values written to Index and Bank registers
283 * are out of range. Normally, the value is simply truncated
284 * to fit the field, but this case is most likely a serious
285 * coding error in the ASL.
286 *
287 ******************************************************************************/
288
289static u8
290acpi_ex_register_overflow(union acpi_operand_object *obj_desc, u64 value)
291{
292
293 if (obj_desc->common_field.bit_length >= ACPI_INTEGER_BIT_SIZE) {
294 /*
295 * The field is large enough to hold the maximum integer, so we can
296 * never overflow it.
297 */
298 return (FALSE);
299 }
300
301 if (value >= ((u64) 1 << obj_desc->common_field.bit_length)) {
302 /*
303 * The Value is larger than the maximum value that can fit into
304 * the register.
305 */
306 ACPI_ERROR((AE_INFO,
307 "Index value 0x%8.8X%8.8X overflows field width 0x%X",
308 ACPI_FORMAT_UINT64(value),
309 obj_desc->common_field.bit_length));
310
311 return (TRUE);
312 }
313
314 /* The Value will fit into the field with no truncation */
315
316 return (FALSE);
317}
318
319/*******************************************************************************
320 *
321 * FUNCTION: acpi_ex_field_datum_io
322 *
323 * PARAMETERS: obj_desc - Field to be read
324 * field_datum_byte_offset - Byte offset of this datum within the
325 * parent field
326 * value - Where to store value (must be 64 bits)
327 * read_write - Read or Write flag
328 *
329 * RETURN: Status
330 *
331 * DESCRIPTION: Read or Write a single datum of a field. The field_type is
332 * demultiplexed here to handle the different types of fields
333 * (buffer_field, region_field, index_field, bank_field)
334 *
335 ******************************************************************************/
336
337static acpi_status
338acpi_ex_field_datum_io(union acpi_operand_object *obj_desc,
339 u32 field_datum_byte_offset, u64 *value, u32 read_write)
340{
341 acpi_status status;
342 u64 local_value;
343
344 ACPI_FUNCTION_TRACE_U32(ex_field_datum_io, field_datum_byte_offset);
345
346 if (read_write == ACPI_READ) {
347 if (!value) {
348 local_value = 0;
349
350 /* To support reads without saving return value */
351 value = &local_value;
352 }
353
354 /* Clear the entire return buffer first, [Very Important!] */
355
356 *value = 0;
357 }
358
359 /*
360 * The four types of fields are:
361 *
362 * buffer_field - Read/write from/to a Buffer
363 * region_field - Read/write from/to a Operation Region.
364 * bank_field - Write to a Bank Register, then read/write from/to an
365 * operation_region
366 * index_field - Write to an Index Register, then read/write from/to a
367 * Data Register
368 */
369 switch (obj_desc->common.type) {
370 case ACPI_TYPE_BUFFER_FIELD:
371 /*
372 * If the buffer_field arguments have not been previously evaluated,
373 * evaluate them now and save the results.
374 */
375 if (!(obj_desc->common.flags & AOPOBJ_DATA_VALID)) {
376 status = acpi_ds_get_buffer_field_arguments(obj_desc);
377 if (ACPI_FAILURE(status)) {
378 return_ACPI_STATUS(status);
379 }
380 }
381
382 if (read_write == ACPI_READ) {
383 /*
384 * Copy the data from the source buffer.
385 * Length is the field width in bytes.
386 */
387 memcpy(to: value,
388 from: (obj_desc->buffer_field.buffer_obj)->buffer.
389 pointer +
390 obj_desc->buffer_field.base_byte_offset +
391 field_datum_byte_offset,
392 len: obj_desc->common_field.access_byte_width);
393 } else {
394 /*
395 * Copy the data to the target buffer.
396 * Length is the field width in bytes.
397 */
398 memcpy(to: (obj_desc->buffer_field.buffer_obj)->buffer.
399 pointer +
400 obj_desc->buffer_field.base_byte_offset +
401 field_datum_byte_offset, from: value,
402 len: obj_desc->common_field.access_byte_width);
403 }
404
405 status = AE_OK;
406 break;
407
408 case ACPI_TYPE_LOCAL_BANK_FIELD:
409 /*
410 * Ensure that the bank_value is not beyond the capacity of
411 * the register
412 */
413 if (acpi_ex_register_overflow(obj_desc: obj_desc->bank_field.bank_obj,
414 value: (u64) obj_desc->bank_field.
415 value)) {
416 return_ACPI_STATUS(AE_AML_REGISTER_LIMIT);
417 }
418
419 /*
420 * For bank_fields, we must write the bank_value to the bank_register
421 * (itself a region_field) before we can access the data.
422 */
423 status =
424 acpi_ex_insert_into_field(obj_desc: obj_desc->bank_field.bank_obj,
425 buffer: &obj_desc->bank_field.value,
426 buffer_length: sizeof(obj_desc->bank_field.
427 value));
428 if (ACPI_FAILURE(status)) {
429 return_ACPI_STATUS(status);
430 }
431
432 /*
433 * Now that the Bank has been selected, fall through to the
434 * region_field case and write the datum to the Operation Region
435 */
436
437 ACPI_FALLTHROUGH;
438
439 case ACPI_TYPE_LOCAL_REGION_FIELD:
440 /*
441 * For simple region_fields, we just directly access the owning
442 * Operation Region.
443 */
444 status =
445 acpi_ex_access_region(obj_desc, field_datum_byte_offset,
446 value, function: read_write);
447 break;
448
449 case ACPI_TYPE_LOCAL_INDEX_FIELD:
450 /*
451 * Ensure that the index_value is not beyond the capacity of
452 * the register
453 */
454 if (acpi_ex_register_overflow(obj_desc: obj_desc->index_field.index_obj,
455 value: (u64) obj_desc->index_field.
456 value)) {
457 return_ACPI_STATUS(AE_AML_REGISTER_LIMIT);
458 }
459
460 /* Write the index value to the index_register (itself a region_field) */
461
462 field_datum_byte_offset += obj_desc->index_field.value;
463
464 ACPI_DEBUG_PRINT((ACPI_DB_BFIELD,
465 "Write to Index Register: Value %8.8X\n",
466 field_datum_byte_offset));
467
468 status =
469 acpi_ex_insert_into_field(obj_desc: obj_desc->index_field.index_obj,
470 buffer: &field_datum_byte_offset,
471 buffer_length: sizeof(field_datum_byte_offset));
472 if (ACPI_FAILURE(status)) {
473 return_ACPI_STATUS(status);
474 }
475
476 if (read_write == ACPI_READ) {
477
478 /* Read the datum from the data_register */
479
480 ACPI_DEBUG_PRINT((ACPI_DB_BFIELD,
481 "Read from Data Register\n"));
482
483 status =
484 acpi_ex_extract_from_field(obj_desc: obj_desc->index_field.
485 data_obj, buffer: value,
486 buffer_length: sizeof(u64));
487 } else {
488 /* Write the datum to the data_register */
489
490 ACPI_DEBUG_PRINT((ACPI_DB_BFIELD,
491 "Write to Data Register: Value %8.8X%8.8X\n",
492 ACPI_FORMAT_UINT64(*value)));
493
494 status =
495 acpi_ex_insert_into_field(obj_desc: obj_desc->index_field.
496 data_obj, buffer: value,
497 buffer_length: sizeof(u64));
498 }
499 break;
500
501 default:
502
503 ACPI_ERROR((AE_INFO, "Wrong object type in field I/O %u",
504 obj_desc->common.type));
505 status = AE_AML_INTERNAL;
506 break;
507 }
508
509 if (ACPI_SUCCESS(status)) {
510 if (read_write == ACPI_READ) {
511 ACPI_DEBUG_PRINT((ACPI_DB_BFIELD,
512 "Value Read %8.8X%8.8X, Width %u\n",
513 ACPI_FORMAT_UINT64(*value),
514 obj_desc->common_field.
515 access_byte_width));
516 } else {
517 ACPI_DEBUG_PRINT((ACPI_DB_BFIELD,
518 "Value Written %8.8X%8.8X, Width %u\n",
519 ACPI_FORMAT_UINT64(*value),
520 obj_desc->common_field.
521 access_byte_width));
522 }
523 }
524
525 return_ACPI_STATUS(status);
526}
527
528/*******************************************************************************
529 *
530 * FUNCTION: acpi_ex_write_with_update_rule
531 *
532 * PARAMETERS: obj_desc - Field to be written
533 * mask - bitmask within field datum
534 * field_value - Value to write
535 * field_datum_byte_offset - Offset of datum within field
536 *
537 * RETURN: Status
538 *
539 * DESCRIPTION: Apply the field update rule to a field write
540 *
541 ******************************************************************************/
542
543acpi_status
544acpi_ex_write_with_update_rule(union acpi_operand_object *obj_desc,
545 u64 mask,
546 u64 field_value, u32 field_datum_byte_offset)
547{
548 acpi_status status = AE_OK;
549 u64 merged_value;
550 u64 current_value;
551
552 ACPI_FUNCTION_TRACE_U32(ex_write_with_update_rule, mask);
553
554 /* Start with the new bits */
555
556 merged_value = field_value;
557
558 /* If the mask is all ones, we don't need to worry about the update rule */
559
560 if (mask != ACPI_UINT64_MAX) {
561
562 /* Decode the update rule */
563
564 switch (obj_desc->common_field.
565 field_flags & AML_FIELD_UPDATE_RULE_MASK) {
566 case AML_FIELD_UPDATE_PRESERVE:
567 /*
568 * Check if update rule needs to be applied (not if mask is all
569 * ones) The left shift drops the bits we want to ignore.
570 */
571 if ((~mask << (ACPI_MUL_8(sizeof(mask)) -
572 ACPI_MUL_8(obj_desc->common_field.
573 access_byte_width))) != 0) {
574 /*
575 * Read the current contents of the byte/word/dword containing
576 * the field, and merge with the new field value.
577 */
578 status =
579 acpi_ex_field_datum_io(obj_desc,
580 field_datum_byte_offset,
581 value: &current_value,
582 ACPI_READ);
583 if (ACPI_FAILURE(status)) {
584 return_ACPI_STATUS(status);
585 }
586
587 merged_value |= (current_value & ~mask);
588 }
589 break;
590
591 case AML_FIELD_UPDATE_WRITE_AS_ONES:
592
593 /* Set positions outside the field to all ones */
594
595 merged_value |= ~mask;
596 break;
597
598 case AML_FIELD_UPDATE_WRITE_AS_ZEROS:
599
600 /* Set positions outside the field to all zeros */
601
602 merged_value &= mask;
603 break;
604
605 default:
606
607 ACPI_ERROR((AE_INFO,
608 "Unknown UpdateRule value: 0x%X",
609 (obj_desc->common_field.field_flags &
610 AML_FIELD_UPDATE_RULE_MASK)));
611 return_ACPI_STATUS(AE_AML_OPERAND_VALUE);
612 }
613 }
614
615 ACPI_DEBUG_PRINT((ACPI_DB_BFIELD,
616 "Mask %8.8X%8.8X, DatumOffset %X, Width %X, "
617 "Value %8.8X%8.8X, MergedValue %8.8X%8.8X\n",
618 ACPI_FORMAT_UINT64(mask),
619 field_datum_byte_offset,
620 obj_desc->common_field.access_byte_width,
621 ACPI_FORMAT_UINT64(field_value),
622 ACPI_FORMAT_UINT64(merged_value)));
623
624 /* Write the merged value */
625
626 status =
627 acpi_ex_field_datum_io(obj_desc, field_datum_byte_offset,
628 value: &merged_value, ACPI_WRITE);
629
630 return_ACPI_STATUS(status);
631}
632
633/*******************************************************************************
634 *
635 * FUNCTION: acpi_ex_extract_from_field
636 *
637 * PARAMETERS: obj_desc - Field to be read
638 * buffer - Where to store the field data
639 * buffer_length - Length of Buffer
640 *
641 * RETURN: Status
642 *
643 * DESCRIPTION: Retrieve the current value of the given field
644 *
645 ******************************************************************************/
646
647acpi_status
648acpi_ex_extract_from_field(union acpi_operand_object *obj_desc,
649 void *buffer, u32 buffer_length)
650{
651 acpi_status status;
652 u64 raw_datum;
653 u64 merged_datum;
654 u32 field_offset = 0;
655 u32 buffer_offset = 0;
656 u32 buffer_tail_bits;
657 u32 datum_count;
658 u32 field_datum_count;
659 u32 access_bit_width;
660 u32 i;
661
662 ACPI_FUNCTION_TRACE(ex_extract_from_field);
663
664 /* Validate target buffer and clear it */
665
666 if (buffer_length <
667 ACPI_ROUND_BITS_UP_TO_BYTES(obj_desc->common_field.bit_length)) {
668 ACPI_ERROR((AE_INFO,
669 "Field size %u (bits) is too large for buffer (%u)",
670 obj_desc->common_field.bit_length, buffer_length));
671
672 return_ACPI_STATUS(AE_BUFFER_OVERFLOW);
673 }
674
675 memset(s: buffer, c: 0, n: buffer_length);
676 access_bit_width = ACPI_MUL_8(obj_desc->common_field.access_byte_width);
677
678 /* Handle the simple case here */
679
680 if ((obj_desc->common_field.start_field_bit_offset == 0) &&
681 (obj_desc->common_field.bit_length == access_bit_width)) {
682 if (buffer_length >= sizeof(u64)) {
683 status =
684 acpi_ex_field_datum_io(obj_desc, field_datum_byte_offset: 0, value: buffer,
685 ACPI_READ);
686 } else {
687 /* Use raw_datum (u64) to handle buffers < 64 bits */
688
689 status =
690 acpi_ex_field_datum_io(obj_desc, field_datum_byte_offset: 0, value: &raw_datum,
691 ACPI_READ);
692 memcpy(to: buffer, from: &raw_datum, len: buffer_length);
693 }
694
695 return_ACPI_STATUS(status);
696 }
697
698/* TBD: Move to common setup code */
699
700 /* Field algorithm is limited to sizeof(u64), truncate if needed */
701
702 if (obj_desc->common_field.access_byte_width > sizeof(u64)) {
703 obj_desc->common_field.access_byte_width = sizeof(u64);
704 access_bit_width = sizeof(u64) * 8;
705 }
706
707 /* Compute the number of datums (access width data items) */
708
709 datum_count =
710 ACPI_ROUND_UP_TO(obj_desc->common_field.bit_length,
711 access_bit_width);
712
713 field_datum_count = ACPI_ROUND_UP_TO(obj_desc->common_field.bit_length +
714 obj_desc->common_field.
715 start_field_bit_offset,
716 access_bit_width);
717
718 /* Priming read from the field */
719
720 status =
721 acpi_ex_field_datum_io(obj_desc, field_datum_byte_offset: field_offset, value: &raw_datum,
722 ACPI_READ);
723 if (ACPI_FAILURE(status)) {
724 return_ACPI_STATUS(status);
725 }
726 merged_datum =
727 raw_datum >> obj_desc->common_field.start_field_bit_offset;
728
729 /* Read the rest of the field */
730
731 for (i = 1; i < field_datum_count; i++) {
732
733 /* Get next input datum from the field */
734
735 field_offset += obj_desc->common_field.access_byte_width;
736 status =
737 acpi_ex_field_datum_io(obj_desc, field_datum_byte_offset: field_offset, value: &raw_datum,
738 ACPI_READ);
739 if (ACPI_FAILURE(status)) {
740 return_ACPI_STATUS(status);
741 }
742
743 /*
744 * Merge with previous datum if necessary.
745 *
746 * Note: Before the shift, check if the shift value will be larger than
747 * the integer size. If so, there is no need to perform the operation.
748 * This avoids the differences in behavior between different compilers
749 * concerning shift values larger than the target data width.
750 */
751 if (access_bit_width -
752 obj_desc->common_field.start_field_bit_offset <
753 ACPI_INTEGER_BIT_SIZE) {
754 merged_datum |=
755 raw_datum << (access_bit_width -
756 obj_desc->common_field.
757 start_field_bit_offset);
758 }
759
760 if (i == datum_count) {
761 break;
762 }
763
764 /* Write merged datum to target buffer */
765
766 memcpy(to: ((char *)buffer) + buffer_offset, from: &merged_datum,
767 ACPI_MIN(obj_desc->common_field.access_byte_width,
768 buffer_length - buffer_offset));
769
770 buffer_offset += obj_desc->common_field.access_byte_width;
771 merged_datum =
772 raw_datum >> obj_desc->common_field.start_field_bit_offset;
773 }
774
775 /* Mask off any extra bits in the last datum */
776
777 buffer_tail_bits = obj_desc->common_field.bit_length % access_bit_width;
778 if (buffer_tail_bits) {
779 merged_datum &= ACPI_MASK_BITS_ABOVE(buffer_tail_bits);
780 }
781
782 /* Write the last datum to the buffer */
783
784 memcpy(to: ((char *)buffer) + buffer_offset, from: &merged_datum,
785 ACPI_MIN(obj_desc->common_field.access_byte_width,
786 buffer_length - buffer_offset));
787
788 return_ACPI_STATUS(AE_OK);
789}
790
791/*******************************************************************************
792 *
793 * FUNCTION: acpi_ex_insert_into_field
794 *
795 * PARAMETERS: obj_desc - Field to be written
796 * buffer - Data to be written
797 * buffer_length - Length of Buffer
798 *
799 * RETURN: Status
800 *
801 * DESCRIPTION: Store the Buffer contents into the given field
802 *
803 ******************************************************************************/
804
805acpi_status
806acpi_ex_insert_into_field(union acpi_operand_object *obj_desc,
807 void *buffer, u32 buffer_length)
808{
809 void *new_buffer;
810 acpi_status status;
811 u64 mask;
812 u64 width_mask;
813 u64 merged_datum;
814 u64 raw_datum = 0;
815 u32 field_offset = 0;
816 u32 buffer_offset = 0;
817 u32 buffer_tail_bits;
818 u32 datum_count;
819 u32 field_datum_count;
820 u32 access_bit_width;
821 u32 required_length;
822 u32 i;
823
824 ACPI_FUNCTION_TRACE(ex_insert_into_field);
825
826 /* Validate input buffer */
827
828 new_buffer = NULL;
829 required_length =
830 ACPI_ROUND_BITS_UP_TO_BYTES(obj_desc->common_field.bit_length);
831
832 /*
833 * We must have a buffer that is at least as long as the field
834 * we are writing to. This is because individual fields are
835 * indivisible and partial writes are not supported -- as per
836 * the ACPI specification.
837 */
838 if (buffer_length < required_length) {
839
840 /* We need to create a new buffer */
841
842 new_buffer = ACPI_ALLOCATE_ZEROED(required_length);
843 if (!new_buffer) {
844 return_ACPI_STATUS(AE_NO_MEMORY);
845 }
846
847 /*
848 * Copy the original data to the new buffer, starting
849 * at Byte zero. All unused (upper) bytes of the
850 * buffer will be 0.
851 */
852 memcpy(to: (char *)new_buffer, from: (char *)buffer, len: buffer_length);
853 buffer = new_buffer;
854 buffer_length = required_length;
855 }
856
857/* TBD: Move to common setup code */
858
859 /* Algo is limited to sizeof(u64), so cut the access_byte_width */
860 if (obj_desc->common_field.access_byte_width > sizeof(u64)) {
861 obj_desc->common_field.access_byte_width = sizeof(u64);
862 }
863
864 access_bit_width = ACPI_MUL_8(obj_desc->common_field.access_byte_width);
865
866 /* Create the bitmasks used for bit insertion */
867
868 width_mask = ACPI_MASK_BITS_ABOVE_64(access_bit_width);
869 mask = width_mask &
870 ACPI_MASK_BITS_BELOW(obj_desc->common_field.start_field_bit_offset);
871
872 /* Compute the number of datums (access width data items) */
873
874 datum_count = ACPI_ROUND_UP_TO(obj_desc->common_field.bit_length,
875 access_bit_width);
876
877 field_datum_count = ACPI_ROUND_UP_TO(obj_desc->common_field.bit_length +
878 obj_desc->common_field.
879 start_field_bit_offset,
880 access_bit_width);
881
882 /* Get initial Datum from the input buffer */
883
884 memcpy(to: &raw_datum, from: buffer,
885 ACPI_MIN(obj_desc->common_field.access_byte_width,
886 buffer_length - buffer_offset));
887
888 merged_datum =
889 raw_datum << obj_desc->common_field.start_field_bit_offset;
890
891 /* Write the entire field */
892
893 for (i = 1; i < field_datum_count; i++) {
894
895 /* Write merged datum to the target field */
896
897 merged_datum &= mask;
898 status =
899 acpi_ex_write_with_update_rule(obj_desc, mask, field_value: merged_datum,
900 field_datum_byte_offset: field_offset);
901 if (ACPI_FAILURE(status)) {
902 goto exit;
903 }
904
905 field_offset += obj_desc->common_field.access_byte_width;
906
907 /*
908 * Start new output datum by merging with previous input datum
909 * if necessary.
910 *
911 * Note: Before the shift, check if the shift value will be larger than
912 * the integer size. If so, there is no need to perform the operation.
913 * This avoids the differences in behavior between different compilers
914 * concerning shift values larger than the target data width.
915 */
916 if ((access_bit_width -
917 obj_desc->common_field.start_field_bit_offset) <
918 ACPI_INTEGER_BIT_SIZE) {
919 merged_datum =
920 raw_datum >> (access_bit_width -
921 obj_desc->common_field.
922 start_field_bit_offset);
923 } else {
924 merged_datum = 0;
925 }
926
927 mask = width_mask;
928
929 if (i == datum_count) {
930 break;
931 }
932
933 /* Get the next input datum from the buffer */
934
935 buffer_offset += obj_desc->common_field.access_byte_width;
936 memcpy(to: &raw_datum, from: ((char *)buffer) + buffer_offset,
937 ACPI_MIN(obj_desc->common_field.access_byte_width,
938 buffer_length - buffer_offset));
939
940 merged_datum |=
941 raw_datum << obj_desc->common_field.start_field_bit_offset;
942 }
943
944 /* Mask off any extra bits in the last datum */
945
946 buffer_tail_bits = (obj_desc->common_field.bit_length +
947 obj_desc->common_field.start_field_bit_offset) %
948 access_bit_width;
949 if (buffer_tail_bits) {
950 mask &= ACPI_MASK_BITS_ABOVE(buffer_tail_bits);
951 }
952
953 /* Write the last datum to the field */
954
955 merged_datum &= mask;
956 status =
957 acpi_ex_write_with_update_rule(obj_desc, mask, field_value: merged_datum,
958 field_datum_byte_offset: field_offset);
959
960exit:
961 /* Free temporary buffer if we used one */
962
963 if (new_buffer) {
964 ACPI_FREE(new_buffer);
965 }
966 return_ACPI_STATUS(status);
967}
968