1// SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0
2/******************************************************************************
3 *
4 * Module Name: exprep - ACPI AML field prep utilities
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 "acnamesp.h"
15#include "acdispat.h"
16
17#define _COMPONENT ACPI_EXECUTER
18ACPI_MODULE_NAME("exprep")
19
20/* Local prototypes */
21static u32
22acpi_ex_decode_field_access(union acpi_operand_object *obj_desc,
23 u8 field_flags, u32 * return_byte_alignment);
24
25#ifdef ACPI_UNDER_DEVELOPMENT
26
27static u32
28acpi_ex_generate_access(u32 field_bit_offset,
29 u32 field_bit_length, u32 region_length);
30
31/*******************************************************************************
32 *
33 * FUNCTION: acpi_ex_generate_access
34 *
35 * PARAMETERS: field_bit_offset - Start of field within parent region/buffer
36 * field_bit_length - Length of field in bits
37 * region_length - Length of parent in bytes
38 *
39 * RETURN: Field granularity (8, 16, 32 or 64) and
40 * byte_alignment (1, 2, 3, or 4)
41 *
42 * DESCRIPTION: Generate an optimal access width for fields defined with the
43 * any_acc keyword.
44 *
45 * NOTE: Need to have the region_length in order to check for boundary
46 * conditions (end-of-region). However, the region_length is a deferred
47 * operation. Therefore, to complete this implementation, the generation
48 * of this access width must be deferred until the region length has
49 * been evaluated.
50 *
51 ******************************************************************************/
52
53static u32
54acpi_ex_generate_access(u32 field_bit_offset,
55 u32 field_bit_length, u32 region_length)
56{
57 u32 field_byte_length;
58 u32 field_byte_offset;
59 u32 field_byte_end_offset;
60 u32 access_byte_width;
61 u32 field_start_offset;
62 u32 field_end_offset;
63 u32 minimum_access_width = 0xFFFFFFFF;
64 u32 minimum_accesses = 0xFFFFFFFF;
65 u32 accesses;
66
67 ACPI_FUNCTION_TRACE(ex_generate_access);
68
69 /* Round Field start offset and length to "minimal" byte boundaries */
70
71 field_byte_offset = ACPI_DIV_8(ACPI_ROUND_DOWN(field_bit_offset, 8));
72
73 field_byte_end_offset =
74 ACPI_DIV_8(ACPI_ROUND_UP(field_bit_length + field_bit_offset, 8));
75
76 field_byte_length = field_byte_end_offset - field_byte_offset;
77
78 ACPI_DEBUG_PRINT((ACPI_DB_BFIELD,
79 "Bit length %u, Bit offset %u\n",
80 field_bit_length, field_bit_offset));
81
82 ACPI_DEBUG_PRINT((ACPI_DB_BFIELD,
83 "Byte Length %u, Byte Offset %u, End Offset %u\n",
84 field_byte_length, field_byte_offset,
85 field_byte_end_offset));
86
87 /*
88 * Iterative search for the maximum access width that is both aligned
89 * and does not go beyond the end of the region
90 *
91 * Start at byte_acc and work upwards to qword_acc max. (1,2,4,8 bytes)
92 */
93 for (access_byte_width = 1; access_byte_width <= 8;
94 access_byte_width <<= 1) {
95 /*
96 * 1) Round end offset up to next access boundary and make sure that
97 * this does not go beyond the end of the parent region.
98 * 2) When the Access width is greater than the field_byte_length, we
99 * are done. (This does not optimize for the perfectly aligned
100 * case yet).
101 */
102 if (ACPI_ROUND_UP(field_byte_end_offset, access_byte_width) <=
103 region_length) {
104 field_start_offset =
105 ACPI_ROUND_DOWN(field_byte_offset,
106 access_byte_width) /
107 access_byte_width;
108
109 field_end_offset =
110 ACPI_ROUND_UP((field_byte_length +
111 field_byte_offset),
112 access_byte_width) /
113 access_byte_width;
114
115 accesses = field_end_offset - field_start_offset;
116
117 ACPI_DEBUG_PRINT((ACPI_DB_BFIELD,
118 "AccessWidth %u end is within region\n",
119 access_byte_width));
120
121 ACPI_DEBUG_PRINT((ACPI_DB_BFIELD,
122 "Field Start %u, Field End %u -- requires %u accesses\n",
123 field_start_offset, field_end_offset,
124 accesses));
125
126 /* Single access is optimal */
127
128 if (accesses <= 1) {
129 ACPI_DEBUG_PRINT((ACPI_DB_BFIELD,
130 "Entire field can be accessed "
131 "with one operation of size %u\n",
132 access_byte_width));
133 return_VALUE(access_byte_width);
134 }
135
136 /*
137 * Fits in the region, but requires more than one read/write.
138 * try the next wider access on next iteration
139 */
140 if (accesses < minimum_accesses) {
141 minimum_accesses = accesses;
142 minimum_access_width = access_byte_width;
143 }
144 } else {
145 ACPI_DEBUG_PRINT((ACPI_DB_BFIELD,
146 "AccessWidth %u end is NOT within region\n",
147 access_byte_width));
148 if (access_byte_width == 1) {
149 ACPI_DEBUG_PRINT((ACPI_DB_BFIELD,
150 "Field goes beyond end-of-region!\n"));
151
152 /* Field does not fit in the region at all */
153
154 return_VALUE(0);
155 }
156
157 /*
158 * This width goes beyond the end-of-region, back off to
159 * previous access
160 */
161 ACPI_DEBUG_PRINT((ACPI_DB_BFIELD,
162 "Backing off to previous optimal access width of %u\n",
163 minimum_access_width));
164 return_VALUE(minimum_access_width);
165 }
166 }
167
168 /*
169 * Could not read/write field with one operation,
170 * just use max access width
171 */
172 ACPI_DEBUG_PRINT((ACPI_DB_BFIELD,
173 "Cannot access field in one operation, using width 8\n"));
174
175 return_VALUE(8);
176}
177#endif /* ACPI_UNDER_DEVELOPMENT */
178
179/*******************************************************************************
180 *
181 * FUNCTION: acpi_ex_decode_field_access
182 *
183 * PARAMETERS: obj_desc - Field object
184 * field_flags - Encoded fieldflags (contains access bits)
185 * return_byte_alignment - Where the byte alignment is returned
186 *
187 * RETURN: Field granularity (8, 16, 32 or 64) and
188 * byte_alignment (1, 2, 3, or 4)
189 *
190 * DESCRIPTION: Decode the access_type bits of a field definition.
191 *
192 ******************************************************************************/
193
194static u32
195acpi_ex_decode_field_access(union acpi_operand_object *obj_desc,
196 u8 field_flags, u32 * return_byte_alignment)
197{
198 u32 access;
199 u32 byte_alignment;
200 u32 bit_length;
201
202 ACPI_FUNCTION_TRACE(ex_decode_field_access);
203
204 access = (field_flags & AML_FIELD_ACCESS_TYPE_MASK);
205
206 switch (access) {
207 case AML_FIELD_ACCESS_ANY:
208
209#ifdef ACPI_UNDER_DEVELOPMENT
210 byte_alignment =
211 acpi_ex_generate_access(obj_desc->common_field.
212 start_field_bit_offset,
213 obj_desc->common_field.bit_length,
214 0xFFFFFFFF
215 /* Temp until we pass region_length as parameter */
216 );
217 bit_length = byte_alignment * 8;
218#endif
219
220 byte_alignment = 1;
221 bit_length = 8;
222 break;
223
224 case AML_FIELD_ACCESS_BYTE:
225 case AML_FIELD_ACCESS_BUFFER: /* ACPI 2.0 (SMBus Buffer) */
226
227 byte_alignment = 1;
228 bit_length = 8;
229 break;
230
231 case AML_FIELD_ACCESS_WORD:
232
233 byte_alignment = 2;
234 bit_length = 16;
235 break;
236
237 case AML_FIELD_ACCESS_DWORD:
238
239 byte_alignment = 4;
240 bit_length = 32;
241 break;
242
243 case AML_FIELD_ACCESS_QWORD: /* ACPI 2.0 */
244
245 byte_alignment = 8;
246 bit_length = 64;
247 break;
248
249 default:
250
251 /* Invalid field access type */
252
253 ACPI_ERROR((AE_INFO, "Unknown field access type 0x%X", access));
254
255 return_UINT32(0);
256 }
257
258 if (obj_desc->common.type == ACPI_TYPE_BUFFER_FIELD) {
259 /*
260 * buffer_field access can be on any byte boundary, so the
261 * byte_alignment is always 1 byte -- regardless of any byte_alignment
262 * implied by the field access type.
263 */
264 byte_alignment = 1;
265 }
266
267 *return_byte_alignment = byte_alignment;
268 return_UINT32(bit_length);
269}
270
271/*******************************************************************************
272 *
273 * FUNCTION: acpi_ex_prep_common_field_object
274 *
275 * PARAMETERS: obj_desc - The field object
276 * field_flags - Access, lock_rule, and update_rule.
277 * The format of a field_flag is described
278 * in the ACPI specification
279 * field_attribute - Special attributes (not used)
280 * field_bit_position - Field start position
281 * field_bit_length - Field length in number of bits
282 *
283 * RETURN: Status
284 *
285 * DESCRIPTION: Initialize the areas of the field object that are common
286 * to the various types of fields. Note: This is very "sensitive"
287 * code because we are solving the general case for field
288 * alignment.
289 *
290 ******************************************************************************/
291
292acpi_status
293acpi_ex_prep_common_field_object(union acpi_operand_object *obj_desc,
294 u8 field_flags,
295 u8 field_attribute,
296 u32 field_bit_position, u32 field_bit_length)
297{
298 u32 access_bit_width;
299 u32 byte_alignment;
300 u32 nearest_byte_address;
301
302 ACPI_FUNCTION_TRACE(ex_prep_common_field_object);
303
304 /*
305 * Note: the structure being initialized is the
306 * ACPI_COMMON_FIELD_INFO; No structure fields outside of the common
307 * area are initialized by this procedure.
308 */
309 obj_desc->common_field.field_flags = field_flags;
310 obj_desc->common_field.attribute = field_attribute;
311 obj_desc->common_field.bit_length = field_bit_length;
312
313 /*
314 * Decode the access type so we can compute offsets. The access type gives
315 * two pieces of information - the width of each field access and the
316 * necessary byte_alignment (address granularity) of the access.
317 *
318 * For any_acc, the access_bit_width is the largest width that is both
319 * necessary and possible in an attempt to access the whole field in one
320 * I/O operation. However, for any_acc, the byte_alignment is always one
321 * byte.
322 *
323 * For all Buffer Fields, the byte_alignment is always one byte.
324 *
325 * For all other access types (Byte, Word, Dword, Qword), the Bitwidth is
326 * the same (equivalent) as the byte_alignment.
327 */
328 access_bit_width =
329 acpi_ex_decode_field_access(obj_desc, field_flags, return_byte_alignment: &byte_alignment);
330 if (!access_bit_width) {
331 return_ACPI_STATUS(AE_AML_OPERAND_VALUE);
332 }
333
334 /* Setup width (access granularity) fields (values are: 1, 2, 4, 8) */
335
336 obj_desc->common_field.access_byte_width = (u8)
337 ACPI_DIV_8(access_bit_width);
338
339 /*
340 * base_byte_offset is the address of the start of the field within the
341 * region. It is the byte address of the first *datum* (field-width data
342 * unit) of the field. (i.e., the first datum that contains at least the
343 * first *bit* of the field.)
344 *
345 * Note: byte_alignment is always either equal to the access_bit_width or 8
346 * (Byte access), and it defines the addressing granularity of the parent
347 * region or buffer.
348 */
349 nearest_byte_address =
350 ACPI_ROUND_BITS_DOWN_TO_BYTES(field_bit_position);
351 obj_desc->common_field.base_byte_offset = (u32)
352 ACPI_ROUND_DOWN(nearest_byte_address, byte_alignment);
353
354 /*
355 * start_field_bit_offset is the offset of the first bit of the field within
356 * a field datum.
357 */
358 obj_desc->common_field.start_field_bit_offset = (u8)
359 (field_bit_position -
360 ACPI_MUL_8(obj_desc->common_field.base_byte_offset));
361
362 return_ACPI_STATUS(AE_OK);
363}
364
365/*******************************************************************************
366 *
367 * FUNCTION: acpi_ex_prep_field_value
368 *
369 * PARAMETERS: info - Contains all field creation info
370 *
371 * RETURN: Status
372 *
373 * DESCRIPTION: Construct an object of type union acpi_operand_object with a
374 * subtype of def_field and connect it to the parent Node.
375 *
376 ******************************************************************************/
377
378acpi_status acpi_ex_prep_field_value(struct acpi_create_field_info *info)
379{
380 union acpi_operand_object *obj_desc;
381 union acpi_operand_object *second_desc = NULL;
382 acpi_status status;
383 u32 access_byte_width;
384 u32 type;
385
386 ACPI_FUNCTION_TRACE(ex_prep_field_value);
387
388 /* Parameter validation */
389
390 if (info->field_type != ACPI_TYPE_LOCAL_INDEX_FIELD) {
391 if (!info->region_node) {
392 ACPI_ERROR((AE_INFO, "Null RegionNode"));
393 return_ACPI_STATUS(AE_AML_NO_OPERAND);
394 }
395
396 type = acpi_ns_get_type(node: info->region_node);
397 if (type != ACPI_TYPE_REGION) {
398 ACPI_ERROR((AE_INFO,
399 "Needed Region, found type 0x%X (%s)", type,
400 acpi_ut_get_type_name(type)));
401
402 return_ACPI_STATUS(AE_AML_OPERAND_TYPE);
403 }
404 }
405
406 /* Allocate a new field object */
407
408 obj_desc = acpi_ut_create_internal_object(info->field_type);
409 if (!obj_desc) {
410 return_ACPI_STATUS(AE_NO_MEMORY);
411 }
412
413 /* Initialize areas of the object that are common to all fields */
414
415 obj_desc->common_field.node = info->field_node;
416 status = acpi_ex_prep_common_field_object(obj_desc,
417 field_flags: info->field_flags,
418 field_attribute: info->attribute,
419 field_bit_position: info->field_bit_position,
420 field_bit_length: info->field_bit_length);
421 if (ACPI_FAILURE(status)) {
422 acpi_ut_delete_object_desc(object: obj_desc);
423 return_ACPI_STATUS(status);
424 }
425
426 /* Initialize areas of the object that are specific to the field type */
427
428 switch (info->field_type) {
429 case ACPI_TYPE_LOCAL_REGION_FIELD:
430
431 obj_desc->field.region_obj =
432 acpi_ns_get_attached_object(node: info->region_node);
433
434 /* Fields specific to generic_serial_bus fields */
435
436 obj_desc->field.access_length = info->access_length;
437
438 if (info->connection_node) {
439 second_desc = info->connection_node->object;
440 if (second_desc == NULL) {
441 break;
442 }
443 if (!(second_desc->common.flags & AOPOBJ_DATA_VALID)) {
444 status =
445 acpi_ds_get_buffer_arguments(obj_desc: second_desc);
446 if (ACPI_FAILURE(status)) {
447 acpi_ut_delete_object_desc(object: obj_desc);
448 return_ACPI_STATUS(status);
449 }
450 }
451
452 obj_desc->field.resource_buffer =
453 second_desc->buffer.pointer;
454 obj_desc->field.resource_length =
455 (u16)second_desc->buffer.length;
456 } else if (info->resource_buffer) {
457 obj_desc->field.resource_buffer = info->resource_buffer;
458 obj_desc->field.resource_length = info->resource_length;
459 }
460
461 obj_desc->field.pin_number_index = info->pin_number_index;
462
463 /* Allow full data read from EC address space */
464
465 if ((obj_desc->field.region_obj->region.space_id ==
466 ACPI_ADR_SPACE_EC)
467 && (obj_desc->common_field.bit_length > 8)) {
468 access_byte_width =
469 ACPI_ROUND_BITS_UP_TO_BYTES(obj_desc->common_field.
470 bit_length);
471
472 /* Maximum byte width supported is 255 */
473
474 if (access_byte_width < 256) {
475 obj_desc->common_field.access_byte_width =
476 (u8)access_byte_width;
477 }
478 }
479 ACPI_DEBUG_PRINT((ACPI_DB_BFIELD,
480 "RegionField: BitOff %X, Off %X, Gran %X, Region %p\n",
481 obj_desc->field.start_field_bit_offset,
482 obj_desc->field.base_byte_offset,
483 obj_desc->field.access_byte_width,
484 obj_desc->field.region_obj));
485 break;
486
487 case ACPI_TYPE_LOCAL_BANK_FIELD:
488
489 obj_desc->bank_field.value = info->bank_value;
490 obj_desc->bank_field.region_obj =
491 acpi_ns_get_attached_object(node: info->region_node);
492 obj_desc->bank_field.bank_obj =
493 acpi_ns_get_attached_object(node: info->register_node);
494
495 /* An additional reference for the attached objects */
496
497 acpi_ut_add_reference(object: obj_desc->bank_field.region_obj);
498 acpi_ut_add_reference(object: obj_desc->bank_field.bank_obj);
499
500 ACPI_DEBUG_PRINT((ACPI_DB_BFIELD,
501 "Bank Field: BitOff %X, Off %X, Gran %X, Region %p, BankReg %p\n",
502 obj_desc->bank_field.start_field_bit_offset,
503 obj_desc->bank_field.base_byte_offset,
504 obj_desc->field.access_byte_width,
505 obj_desc->bank_field.region_obj,
506 obj_desc->bank_field.bank_obj));
507
508 /*
509 * Remember location in AML stream of the field unit
510 * opcode and operands -- since the bank_value
511 * operands must be evaluated.
512 */
513 second_desc = obj_desc->common.next_object;
514 second_desc->extra.aml_start =
515 ACPI_CAST_PTR(union acpi_parse_object,
516 info->data_register_node)->named.data;
517 second_desc->extra.aml_length =
518 ACPI_CAST_PTR(union acpi_parse_object,
519 info->data_register_node)->named.length;
520
521 break;
522
523 case ACPI_TYPE_LOCAL_INDEX_FIELD:
524
525 /* Get the Index and Data registers */
526
527 obj_desc->index_field.index_obj =
528 acpi_ns_get_attached_object(node: info->register_node);
529 obj_desc->index_field.data_obj =
530 acpi_ns_get_attached_object(node: info->data_register_node);
531
532 if (!obj_desc->index_field.data_obj
533 || !obj_desc->index_field.index_obj) {
534 ACPI_ERROR((AE_INFO,
535 "Null Index Object during field prep"));
536 acpi_ut_delete_object_desc(object: obj_desc);
537 return_ACPI_STATUS(AE_AML_INTERNAL);
538 }
539
540 /* An additional reference for the attached objects */
541
542 acpi_ut_add_reference(object: obj_desc->index_field.data_obj);
543 acpi_ut_add_reference(object: obj_desc->index_field.index_obj);
544
545 /*
546 * April 2006: Changed to match MS behavior
547 *
548 * The value written to the Index register is the byte offset of the
549 * target field in units of the granularity of the index_field
550 *
551 * Previously, the value was calculated as an index in terms of the
552 * width of the Data register, as below:
553 *
554 * obj_desc->index_field.Value = (u32)
555 * (Info->field_bit_position / ACPI_MUL_8 (
556 * obj_desc->Field.access_byte_width));
557 *
558 * February 2006: Tried value as a byte offset:
559 * obj_desc->index_field.Value = (u32)
560 * ACPI_DIV_8 (Info->field_bit_position);
561 */
562 obj_desc->index_field.value =
563 (u32) ACPI_ROUND_DOWN(ACPI_DIV_8(info->field_bit_position),
564 obj_desc->index_field.
565 access_byte_width);
566
567 ACPI_DEBUG_PRINT((ACPI_DB_BFIELD,
568 "IndexField: BitOff %X, Off %X, Value %X, "
569 "Gran %X, Index %p, Data %p\n",
570 obj_desc->index_field.start_field_bit_offset,
571 obj_desc->index_field.base_byte_offset,
572 obj_desc->index_field.value,
573 obj_desc->field.access_byte_width,
574 obj_desc->index_field.index_obj,
575 obj_desc->index_field.data_obj));
576 break;
577
578 default:
579
580 /* No other types should get here */
581
582 break;
583 }
584
585 /*
586 * Store the constructed descriptor (obj_desc) into the parent Node,
587 * preserving the current type of that named_obj.
588 */
589 status =
590 acpi_ns_attach_object(node: info->field_node, object: obj_desc,
591 type: acpi_ns_get_type(node: info->field_node));
592
593 ACPI_DEBUG_PRINT((ACPI_DB_BFIELD,
594 "Set NamedObj %p [%4.4s], ObjDesc %p\n",
595 info->field_node,
596 acpi_ut_get_node_name(info->field_node), obj_desc));
597
598 /* Remove local reference to the object */
599
600 acpi_ut_remove_reference(object: obj_desc);
601 return_ACPI_STATUS(status);
602}
603