1 // SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0
2 /******************************************************************************
4 * Module Name: exprep - ACPI AML field prep utilities
6 * Copyright (C) 2000 - 2023, Intel Corp.
8 *****************************************************************************/
10 #include <acpi/acpi.h>
17 #define _COMPONENT ACPI_EXECUTER
18 ACPI_MODULE_NAME("exprep")
20 /* Local prototypes */
22 acpi_ex_decode_field_access(union acpi_operand_object
*obj_desc
,
23 u8 field_flags
, u32
* return_byte_alignment
);
25 #ifdef ACPI_UNDER_DEVELOPMENT
28 acpi_ex_generate_access(u32 field_bit_offset
,
29 u32 field_bit_length
, u32 region_length
);
31 /*******************************************************************************
33 * FUNCTION: acpi_ex_generate_access
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
39 * RETURN: Field granularity (8, 16, 32 or 64) and
40 * byte_alignment (1, 2, 3, or 4)
42 * DESCRIPTION: Generate an optimal access width for fields defined with the
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
51 ******************************************************************************/
54 acpi_ex_generate_access(u32 field_bit_offset
,
55 u32 field_bit_length
, u32 region_length
)
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
;
63 u32 minimum_access_width
= 0xFFFFFFFF;
64 u32 minimum_accesses
= 0xFFFFFFFF;
67 ACPI_FUNCTION_TRACE(ex_generate_access
);
69 /* Round Field start offset and length to "minimal" byte boundaries */
71 field_byte_offset
= ACPI_DIV_8(ACPI_ROUND_DOWN(field_bit_offset
, 8));
73 field_byte_end_offset
=
74 ACPI_DIV_8(ACPI_ROUND_UP(field_bit_length
+ field_bit_offset
, 8));
76 field_byte_length
= field_byte_end_offset
- field_byte_offset
;
78 ACPI_DEBUG_PRINT((ACPI_DB_BFIELD
,
79 "Bit length %u, Bit offset %u\n",
80 field_bit_length
, field_bit_offset
));
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
));
88 * Iterative search for the maximum access width that is both aligned
89 * and does not go beyond the end of the region
91 * Start at byte_acc and work upwards to qword_acc max. (1,2,4,8 bytes)
93 for (access_byte_width
= 1; access_byte_width
<= 8;
94 access_byte_width
<<= 1) {
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
102 if (ACPI_ROUND_UP(field_byte_end_offset
, access_byte_width
) <=
105 ACPI_ROUND_DOWN(field_byte_offset
,
110 ACPI_ROUND_UP((field_byte_length
+
115 accesses
= field_end_offset
- field_start_offset
;
117 ACPI_DEBUG_PRINT((ACPI_DB_BFIELD
,
118 "AccessWidth %u end is within region\n",
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
,
126 /* Single access is optimal */
129 ACPI_DEBUG_PRINT((ACPI_DB_BFIELD
,
130 "Entire field can be accessed "
131 "with one operation of size %u\n",
133 return_VALUE(access_byte_width
);
137 * Fits in the region, but requires more than one read/write.
138 * try the next wider access on next iteration
140 if (accesses
< minimum_accesses
) {
141 minimum_accesses
= accesses
;
142 minimum_access_width
= access_byte_width
;
145 ACPI_DEBUG_PRINT((ACPI_DB_BFIELD
,
146 "AccessWidth %u end is NOT within region\n",
148 if (access_byte_width
== 1) {
149 ACPI_DEBUG_PRINT((ACPI_DB_BFIELD
,
150 "Field goes beyond end-of-region!\n"));
152 /* Field does not fit in the region at all */
158 * This width goes beyond the end-of-region, back off to
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
);
169 * Could not read/write field with one operation,
170 * just use max access width
172 ACPI_DEBUG_PRINT((ACPI_DB_BFIELD
,
173 "Cannot access field in one operation, using width 8\n"));
177 #endif /* ACPI_UNDER_DEVELOPMENT */
179 /*******************************************************************************
181 * FUNCTION: acpi_ex_decode_field_access
183 * PARAMETERS: obj_desc - Field object
184 * field_flags - Encoded fieldflags (contains access bits)
185 * return_byte_alignment - Where the byte alignment is returned
187 * RETURN: Field granularity (8, 16, 32 or 64) and
188 * byte_alignment (1, 2, 3, or 4)
190 * DESCRIPTION: Decode the access_type bits of a field definition.
192 ******************************************************************************/
195 acpi_ex_decode_field_access(union acpi_operand_object
*obj_desc
,
196 u8 field_flags
, u32
* return_byte_alignment
)
202 ACPI_FUNCTION_TRACE(ex_decode_field_access
);
204 access
= (field_flags
& AML_FIELD_ACCESS_TYPE_MASK
);
207 case AML_FIELD_ACCESS_ANY
:
209 #ifdef ACPI_UNDER_DEVELOPMENT
211 acpi_ex_generate_access(obj_desc
->common_field
.
212 start_field_bit_offset
,
213 obj_desc
->common_field
.bit_length
,
215 /* Temp until we pass region_length as parameter */
217 bit_length
= byte_alignment
* 8;
224 case AML_FIELD_ACCESS_BYTE
:
225 case AML_FIELD_ACCESS_BUFFER
: /* ACPI 2.0 (SMBus Buffer) */
231 case AML_FIELD_ACCESS_WORD
:
237 case AML_FIELD_ACCESS_DWORD
:
243 case AML_FIELD_ACCESS_QWORD
: /* ACPI 2.0 */
251 /* Invalid field access type */
253 ACPI_ERROR((AE_INFO
, "Unknown field access type 0x%X", access
));
258 if (obj_desc
->common
.type
== ACPI_TYPE_BUFFER_FIELD
) {
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.
267 *return_byte_alignment
= byte_alignment
;
268 return_UINT32(bit_length
);
271 /*******************************************************************************
273 * FUNCTION: acpi_ex_prep_common_field_object
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
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
290 ******************************************************************************/
293 acpi_ex_prep_common_field_object(union acpi_operand_object
*obj_desc
,
296 u32 field_bit_position
, u32 field_bit_length
)
298 u32 access_bit_width
;
300 u32 nearest_byte_address
;
302 ACPI_FUNCTION_TRACE(ex_prep_common_field_object
);
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.
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
;
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.
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
323 * For all Buffer Fields, the byte_alignment is always one byte.
325 * For all other access types (Byte, Word, Dword, Qword), the Bitwidth is
326 * the same (equivalent) as the byte_alignment.
329 acpi_ex_decode_field_access(obj_desc
, field_flags
, &byte_alignment
);
330 if (!access_bit_width
) {
331 return_ACPI_STATUS(AE_AML_OPERAND_VALUE
);
334 /* Setup width (access granularity) fields (values are: 1, 2, 4, 8) */
336 obj_desc
->common_field
.access_byte_width
= (u8
)
337 ACPI_DIV_8(access_bit_width
);
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.)
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
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
);
355 * start_field_bit_offset is the offset of the first bit of the field within
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
));
362 return_ACPI_STATUS(AE_OK
);
365 /*******************************************************************************
367 * FUNCTION: acpi_ex_prep_field_value
369 * PARAMETERS: info - Contains all field creation info
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.
376 ******************************************************************************/
378 acpi_status
acpi_ex_prep_field_value(struct acpi_create_field_info
*info
)
380 union acpi_operand_object
*obj_desc
;
381 union acpi_operand_object
*second_desc
= NULL
;
383 u32 access_byte_width
;
386 ACPI_FUNCTION_TRACE(ex_prep_field_value
);
388 /* Parameter validation */
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
);
396 type
= acpi_ns_get_type(info
->region_node
);
397 if (type
!= ACPI_TYPE_REGION
) {
399 "Needed Region, found type 0x%X (%s)", type
,
400 acpi_ut_get_type_name(type
)));
402 return_ACPI_STATUS(AE_AML_OPERAND_TYPE
);
406 /* Allocate a new field object */
408 obj_desc
= acpi_ut_create_internal_object(info
->field_type
);
410 return_ACPI_STATUS(AE_NO_MEMORY
);
413 /* Initialize areas of the object that are common to all fields */
415 obj_desc
->common_field
.node
= info
->field_node
;
416 status
= acpi_ex_prep_common_field_object(obj_desc
,
419 info
->field_bit_position
,
420 info
->field_bit_length
);
421 if (ACPI_FAILURE(status
)) {
422 acpi_ut_delete_object_desc(obj_desc
);
423 return_ACPI_STATUS(status
);
426 /* Initialize areas of the object that are specific to the field type */
428 switch (info
->field_type
) {
429 case ACPI_TYPE_LOCAL_REGION_FIELD
:
431 obj_desc
->field
.region_obj
=
432 acpi_ns_get_attached_object(info
->region_node
);
434 /* Fields specific to generic_serial_bus fields */
436 obj_desc
->field
.access_length
= info
->access_length
;
438 if (info
->connection_node
) {
439 second_desc
= info
->connection_node
->object
;
440 if (second_desc
== NULL
) {
443 if (!(second_desc
->common
.flags
& AOPOBJ_DATA_VALID
)) {
445 acpi_ds_get_buffer_arguments(second_desc
);
446 if (ACPI_FAILURE(status
)) {
447 acpi_ut_delete_object_desc(obj_desc
);
448 return_ACPI_STATUS(status
);
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
;
461 obj_desc
->field
.pin_number_index
= info
->pin_number_index
;
463 /* Allow full data read from EC address space */
465 if ((obj_desc
->field
.region_obj
->region
.space_id
==
467 && (obj_desc
->common_field
.bit_length
> 8)) {
469 ACPI_ROUND_BITS_UP_TO_BYTES(obj_desc
->common_field
.
472 /* Maximum byte width supported is 255 */
474 if (access_byte_width
< 256) {
475 obj_desc
->common_field
.access_byte_width
=
476 (u8
)access_byte_width
;
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
));
487 case ACPI_TYPE_LOCAL_BANK_FIELD
:
489 obj_desc
->bank_field
.value
= info
->bank_value
;
490 obj_desc
->bank_field
.region_obj
=
491 acpi_ns_get_attached_object(info
->region_node
);
492 obj_desc
->bank_field
.bank_obj
=
493 acpi_ns_get_attached_object(info
->register_node
);
495 /* An additional reference for the attached objects */
497 acpi_ut_add_reference(obj_desc
->bank_field
.region_obj
);
498 acpi_ut_add_reference(obj_desc
->bank_field
.bank_obj
);
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
));
509 * Remember location in AML stream of the field unit
510 * opcode and operands -- since the bank_value
511 * operands must be evaluated.
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
;
523 case ACPI_TYPE_LOCAL_INDEX_FIELD
:
525 /* Get the Index and Data registers */
527 obj_desc
->index_field
.index_obj
=
528 acpi_ns_get_attached_object(info
->register_node
);
529 obj_desc
->index_field
.data_obj
=
530 acpi_ns_get_attached_object(info
->data_register_node
);
532 if (!obj_desc
->index_field
.data_obj
533 || !obj_desc
->index_field
.index_obj
) {
535 "Null Index Object during field prep"));
536 acpi_ut_delete_object_desc(obj_desc
);
537 return_ACPI_STATUS(AE_AML_INTERNAL
);
540 /* An additional reference for the attached objects */
542 acpi_ut_add_reference(obj_desc
->index_field
.data_obj
);
543 acpi_ut_add_reference(obj_desc
->index_field
.index_obj
);
546 * April 2006: Changed to match MS behavior
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
551 * Previously, the value was calculated as an index in terms of the
552 * width of the Data register, as below:
554 * obj_desc->index_field.Value = (u32)
555 * (Info->field_bit_position / ACPI_MUL_8 (
556 * obj_desc->Field.access_byte_width));
558 * February 2006: Tried value as a byte offset:
559 * obj_desc->index_field.Value = (u32)
560 * ACPI_DIV_8 (Info->field_bit_position);
562 obj_desc
->index_field
.value
=
563 (u32
) ACPI_ROUND_DOWN(ACPI_DIV_8(info
->field_bit_position
),
564 obj_desc
->index_field
.
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
));
580 /* No other types should get here */
586 * Store the constructed descriptor (obj_desc) into the parent Node,
587 * preserving the current type of that named_obj.
590 acpi_ns_attach_object(info
->field_node
, obj_desc
,
591 acpi_ns_get_type(info
->field_node
));
593 ACPI_DEBUG_PRINT((ACPI_DB_BFIELD
,
594 "Set NamedObj %p [%4.4s], ObjDesc %p\n",
596 acpi_ut_get_node_name(info
->field_node
), obj_desc
));
598 /* Remove local reference to the object */
600 acpi_ut_remove_reference(obj_desc
);
601 return_ACPI_STATUS(status
);