1 /******************************************************************************
3 * Module Name: exfldio - Aml Field I/O
5 *****************************************************************************/
8 * Copyright (C) 2000 - 2010, Intel Corp.
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
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.
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.
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.
44 #include <acpi/acpi.h>
51 #define _COMPONENT ACPI_EXECUTER
52 ACPI_MODULE_NAME("exfldio")
54 /* Local prototypes */
56 acpi_ex_field_datum_io(union acpi_operand_object
*obj_desc
,
57 u32 field_datum_byte_offset
,
58 acpi_integer
* value
, u32 read_write
);
61 acpi_ex_register_overflow(union acpi_operand_object
*obj_desc
,
65 acpi_ex_setup_region(union acpi_operand_object
*obj_desc
,
66 u32 field_datum_byte_offset
);
68 /*******************************************************************************
70 * FUNCTION: acpi_ex_setup_region
72 * PARAMETERS: obj_desc - Field to be read or written
73 * field_datum_byte_offset - Byte offset of this datum within the
78 * DESCRIPTION: Common processing for acpi_ex_extract_from_field and
79 * acpi_ex_insert_into_field. Initialize the Region if necessary and
80 * validate the request.
82 ******************************************************************************/
85 acpi_ex_setup_region(union acpi_operand_object
*obj_desc
,
86 u32 field_datum_byte_offset
)
88 acpi_status status
= AE_OK
;
89 union acpi_operand_object
*rgn_desc
;
91 ACPI_FUNCTION_TRACE_U32(ex_setup_region
, field_datum_byte_offset
);
93 rgn_desc
= obj_desc
->common_field
.region_obj
;
95 /* We must have a valid region */
97 if (rgn_desc
->common
.type
!= ACPI_TYPE_REGION
) {
98 ACPI_ERROR((AE_INFO
, "Needed Region, found type %X (%s)",
99 rgn_desc
->common
.type
,
100 acpi_ut_get_object_type_name(rgn_desc
)));
102 return_ACPI_STATUS(AE_AML_OPERAND_TYPE
);
106 * If the Region Address and Length have not been previously evaluated,
107 * evaluate them now and save the results.
109 if (!(rgn_desc
->common
.flags
& AOPOBJ_DATA_VALID
)) {
110 status
= acpi_ds_get_region_arguments(rgn_desc
);
111 if (ACPI_FAILURE(status
)) {
112 return_ACPI_STATUS(status
);
116 /* Exit if Address/Length have been disallowed by the host OS */
118 if (rgn_desc
->common
.flags
& AOPOBJ_INVALID
) {
119 return_ACPI_STATUS(AE_AML_ILLEGAL_ADDRESS
);
123 * Exit now for SMBus or IPMI address space, it has a non-linear address space
124 * and the request cannot be directly validated
126 if (rgn_desc
->region
.space_id
== ACPI_ADR_SPACE_SMBUS
||
127 rgn_desc
->region
.space_id
== ACPI_ADR_SPACE_IPMI
) {
129 /* SMBus or IPMI has a non-linear address space */
131 return_ACPI_STATUS(AE_OK
);
133 #ifdef ACPI_UNDER_DEVELOPMENT
135 * If the Field access is any_acc, we can now compute the optimal
136 * access (because we know know the length of the parent region)
138 if (!(obj_desc
->common
.flags
& AOPOBJ_DATA_VALID
)) {
139 if (ACPI_FAILURE(status
)) {
140 return_ACPI_STATUS(status
);
146 * Validate the request. The entire request from the byte offset for a
147 * length of one field datum (access width) must fit within the region.
148 * (Region length is specified in bytes)
150 if (rgn_desc
->region
.length
<
151 (obj_desc
->common_field
.base_byte_offset
+
152 field_datum_byte_offset
+
153 obj_desc
->common_field
.access_byte_width
)) {
154 if (acpi_gbl_enable_interpreter_slack
) {
156 * Slack mode only: We will go ahead and allow access to this
157 * field if it is within the region length rounded up to the next
158 * access width boundary. acpi_size cast for 64-bit compile.
160 if (ACPI_ROUND_UP(rgn_desc
->region
.length
,
161 obj_desc
->common_field
.
162 access_byte_width
) >=
163 ((acpi_size
) obj_desc
->common_field
.
165 obj_desc
->common_field
.access_byte_width
+
166 field_datum_byte_offset
)) {
167 return_ACPI_STATUS(AE_OK
);
171 if (rgn_desc
->region
.length
<
172 obj_desc
->common_field
.access_byte_width
) {
174 * This is the case where the access_type (acc_word, etc.) is wider
175 * than the region itself. For example, a region of length one
176 * byte, and a field with Dword access specified.
179 "Field [%4.4s] access width (%d bytes) too large for region [%4.4s] (length %X)",
180 acpi_ut_get_node_name(obj_desc
->
182 obj_desc
->common_field
.access_byte_width
,
183 acpi_ut_get_node_name(rgn_desc
->region
.
185 rgn_desc
->region
.length
));
189 * Offset rounded up to next multiple of field width
190 * exceeds region length, indicate an error
193 "Field [%4.4s] Base+Offset+Width %X+%X+%X is beyond end of region [%4.4s] (length %X)",
194 acpi_ut_get_node_name(obj_desc
->common_field
.node
),
195 obj_desc
->common_field
.base_byte_offset
,
196 field_datum_byte_offset
,
197 obj_desc
->common_field
.access_byte_width
,
198 acpi_ut_get_node_name(rgn_desc
->region
.node
),
199 rgn_desc
->region
.length
));
201 return_ACPI_STATUS(AE_AML_REGION_LIMIT
);
204 return_ACPI_STATUS(AE_OK
);
207 /*******************************************************************************
209 * FUNCTION: acpi_ex_access_region
211 * PARAMETERS: obj_desc - Field to be read
212 * field_datum_byte_offset - Byte offset of this datum within the
214 * Value - Where to store value (must at least
215 * the size of acpi_integer)
216 * Function - Read or Write flag plus other region-
221 * DESCRIPTION: Read or Write a single field datum to an Operation Region.
223 ******************************************************************************/
226 acpi_ex_access_region(union acpi_operand_object
*obj_desc
,
227 u32 field_datum_byte_offset
,
228 acpi_integer
* value
, u32 function
)
231 union acpi_operand_object
*rgn_desc
;
234 ACPI_FUNCTION_TRACE(ex_access_region
);
237 * Ensure that the region operands are fully evaluated and verify
238 * the validity of the request
240 status
= acpi_ex_setup_region(obj_desc
, field_datum_byte_offset
);
241 if (ACPI_FAILURE(status
)) {
242 return_ACPI_STATUS(status
);
246 * The physical address of this field datum is:
248 * 1) The base of the region, plus
249 * 2) The base offset of the field, plus
250 * 3) The current offset into the field
252 rgn_desc
= obj_desc
->common_field
.region_obj
;
254 obj_desc
->common_field
.base_byte_offset
+ field_datum_byte_offset
;
256 if ((function
& ACPI_IO_MASK
) == ACPI_READ
) {
257 ACPI_DEBUG_PRINT((ACPI_DB_BFIELD
, "[READ]"));
259 ACPI_DEBUG_PRINT((ACPI_DB_BFIELD
, "[WRITE]"));
262 ACPI_DEBUG_PRINT_RAW((ACPI_DB_BFIELD
,
263 " Region [%s:%X], Width %X, ByteBase %X, Offset %X at %p\n",
264 acpi_ut_get_region_name(rgn_desc
->region
.
266 rgn_desc
->region
.space_id
,
267 obj_desc
->common_field
.access_byte_width
,
268 obj_desc
->common_field
.base_byte_offset
,
269 field_datum_byte_offset
, ACPI_CAST_PTR(void,
275 /* Invoke the appropriate address_space/op_region handler */
278 acpi_ev_address_space_dispatch(rgn_desc
, function
, region_offset
,
279 ACPI_MUL_8(obj_desc
->common_field
.
283 if (ACPI_FAILURE(status
)) {
284 if (status
== AE_NOT_IMPLEMENTED
) {
286 "Region %s(%X) not implemented",
287 acpi_ut_get_region_name(rgn_desc
->region
.
289 rgn_desc
->region
.space_id
));
290 } else if (status
== AE_NOT_EXIST
) {
292 "Region %s(%X) has no handler",
293 acpi_ut_get_region_name(rgn_desc
->region
.
295 rgn_desc
->region
.space_id
));
299 return_ACPI_STATUS(status
);
302 /*******************************************************************************
304 * FUNCTION: acpi_ex_register_overflow
306 * PARAMETERS: obj_desc - Register(Field) to be written
307 * Value - Value to be stored
309 * RETURN: TRUE if value overflows the field, FALSE otherwise
311 * DESCRIPTION: Check if a value is out of range of the field being written.
312 * Used to check if the values written to Index and Bank registers
313 * are out of range. Normally, the value is simply truncated
314 * to fit the field, but this case is most likely a serious
315 * coding error in the ASL.
317 ******************************************************************************/
320 acpi_ex_register_overflow(union acpi_operand_object
*obj_desc
,
324 if (obj_desc
->common_field
.bit_length
>= ACPI_INTEGER_BIT_SIZE
) {
326 * The field is large enough to hold the maximum integer, so we can
332 if (value
>= ((acpi_integer
) 1 << obj_desc
->common_field
.bit_length
)) {
334 * The Value is larger than the maximum value that can fit into
340 /* The Value will fit into the field with no truncation */
345 /*******************************************************************************
347 * FUNCTION: acpi_ex_field_datum_io
349 * PARAMETERS: obj_desc - Field to be read
350 * field_datum_byte_offset - Byte offset of this datum within the
352 * Value - Where to store value (must be 64 bits)
353 * read_write - Read or Write flag
357 * DESCRIPTION: Read or Write a single datum of a field. The field_type is
358 * demultiplexed here to handle the different types of fields
359 * (buffer_field, region_field, index_field, bank_field)
361 ******************************************************************************/
364 acpi_ex_field_datum_io(union acpi_operand_object
*obj_desc
,
365 u32 field_datum_byte_offset
,
366 acpi_integer
* value
, u32 read_write
)
369 acpi_integer local_value
;
371 ACPI_FUNCTION_TRACE_U32(ex_field_datum_io
, field_datum_byte_offset
);
373 if (read_write
== ACPI_READ
) {
377 /* To support reads without saving return value */
378 value
= &local_value
;
381 /* Clear the entire return buffer first, [Very Important!] */
387 * The four types of fields are:
389 * buffer_field - Read/write from/to a Buffer
390 * region_field - Read/write from/to a Operation Region.
391 * bank_field - Write to a Bank Register, then read/write from/to an
393 * index_field - Write to an Index Register, then read/write from/to a
396 switch (obj_desc
->common
.type
) {
397 case ACPI_TYPE_BUFFER_FIELD
:
399 * If the buffer_field arguments have not been previously evaluated,
400 * evaluate them now and save the results.
402 if (!(obj_desc
->common
.flags
& AOPOBJ_DATA_VALID
)) {
403 status
= acpi_ds_get_buffer_field_arguments(obj_desc
);
404 if (ACPI_FAILURE(status
)) {
405 return_ACPI_STATUS(status
);
409 if (read_write
== ACPI_READ
) {
411 * Copy the data from the source buffer.
412 * Length is the field width in bytes.
415 (obj_desc
->buffer_field
.buffer_obj
)->buffer
.
417 obj_desc
->buffer_field
.base_byte_offset
+
418 field_datum_byte_offset
,
419 obj_desc
->common_field
.access_byte_width
);
422 * Copy the data to the target buffer.
423 * Length is the field width in bytes.
425 ACPI_MEMCPY((obj_desc
->buffer_field
.buffer_obj
)->buffer
.
427 obj_desc
->buffer_field
.base_byte_offset
+
428 field_datum_byte_offset
, value
,
429 obj_desc
->common_field
.access_byte_width
);
435 case ACPI_TYPE_LOCAL_BANK_FIELD
:
438 * Ensure that the bank_value is not beyond the capacity of
441 if (acpi_ex_register_overflow(obj_desc
->bank_field
.bank_obj
,
442 (acpi_integer
) obj_desc
->
444 return_ACPI_STATUS(AE_AML_REGISTER_LIMIT
);
448 * For bank_fields, we must write the bank_value to the bank_register
449 * (itself a region_field) before we can access the data.
452 acpi_ex_insert_into_field(obj_desc
->bank_field
.bank_obj
,
453 &obj_desc
->bank_field
.value
,
454 sizeof(obj_desc
->bank_field
.
456 if (ACPI_FAILURE(status
)) {
457 return_ACPI_STATUS(status
);
461 * Now that the Bank has been selected, fall through to the
462 * region_field case and write the datum to the Operation Region
465 /*lint -fallthrough */
467 case ACPI_TYPE_LOCAL_REGION_FIELD
:
469 * For simple region_fields, we just directly access the owning
473 acpi_ex_access_region(obj_desc
, field_datum_byte_offset
,
477 case ACPI_TYPE_LOCAL_INDEX_FIELD
:
480 * Ensure that the index_value is not beyond the capacity of
483 if (acpi_ex_register_overflow(obj_desc
->index_field
.index_obj
,
484 (acpi_integer
) obj_desc
->
485 index_field
.value
)) {
486 return_ACPI_STATUS(AE_AML_REGISTER_LIMIT
);
489 /* Write the index value to the index_register (itself a region_field) */
491 field_datum_byte_offset
+= obj_desc
->index_field
.value
;
493 ACPI_DEBUG_PRINT((ACPI_DB_BFIELD
,
494 "Write to Index Register: Value %8.8X\n",
495 field_datum_byte_offset
));
498 acpi_ex_insert_into_field(obj_desc
->index_field
.index_obj
,
499 &field_datum_byte_offset
,
500 sizeof(field_datum_byte_offset
));
501 if (ACPI_FAILURE(status
)) {
502 return_ACPI_STATUS(status
);
505 if (read_write
== ACPI_READ
) {
507 /* Read the datum from the data_register */
509 ACPI_DEBUG_PRINT((ACPI_DB_BFIELD
,
510 "Read from Data Register\n"));
513 acpi_ex_extract_from_field(obj_desc
->index_field
.
515 sizeof(acpi_integer
));
517 /* Write the datum to the data_register */
519 ACPI_DEBUG_PRINT((ACPI_DB_BFIELD
,
520 "Write to Data Register: Value %8.8X%8.8X\n",
521 ACPI_FORMAT_UINT64(*value
)));
524 acpi_ex_insert_into_field(obj_desc
->index_field
.
526 sizeof(acpi_integer
));
532 ACPI_ERROR((AE_INFO
, "Wrong object type in field I/O %X",
533 obj_desc
->common
.type
));
534 status
= AE_AML_INTERNAL
;
538 if (ACPI_SUCCESS(status
)) {
539 if (read_write
== ACPI_READ
) {
540 ACPI_DEBUG_PRINT((ACPI_DB_BFIELD
,
541 "Value Read %8.8X%8.8X, Width %d\n",
542 ACPI_FORMAT_UINT64(*value
),
543 obj_desc
->common_field
.
546 ACPI_DEBUG_PRINT((ACPI_DB_BFIELD
,
547 "Value Written %8.8X%8.8X, Width %d\n",
548 ACPI_FORMAT_UINT64(*value
),
549 obj_desc
->common_field
.
554 return_ACPI_STATUS(status
);
557 /*******************************************************************************
559 * FUNCTION: acpi_ex_write_with_update_rule
561 * PARAMETERS: obj_desc - Field to be written
562 * Mask - bitmask within field datum
563 * field_value - Value to write
564 * field_datum_byte_offset - Offset of datum within field
568 * DESCRIPTION: Apply the field update rule to a field write
570 ******************************************************************************/
573 acpi_ex_write_with_update_rule(union acpi_operand_object
*obj_desc
,
575 acpi_integer field_value
,
576 u32 field_datum_byte_offset
)
578 acpi_status status
= AE_OK
;
579 acpi_integer merged_value
;
580 acpi_integer current_value
;
582 ACPI_FUNCTION_TRACE_U32(ex_write_with_update_rule
, mask
);
584 /* Start with the new bits */
586 merged_value
= field_value
;
588 /* If the mask is all ones, we don't need to worry about the update rule */
590 if (mask
!= ACPI_INTEGER_MAX
) {
592 /* Decode the update rule */
594 switch (obj_desc
->common_field
.
595 field_flags
& AML_FIELD_UPDATE_RULE_MASK
) {
596 case AML_FIELD_UPDATE_PRESERVE
:
598 * Check if update rule needs to be applied (not if mask is all
599 * ones) The left shift drops the bits we want to ignore.
601 if ((~mask
<< (ACPI_MUL_8(sizeof(mask
)) -
602 ACPI_MUL_8(obj_desc
->common_field
.
603 access_byte_width
))) != 0) {
605 * Read the current contents of the byte/word/dword containing
606 * the field, and merge with the new field value.
609 acpi_ex_field_datum_io(obj_desc
,
610 field_datum_byte_offset
,
613 if (ACPI_FAILURE(status
)) {
614 return_ACPI_STATUS(status
);
617 merged_value
|= (current_value
& ~mask
);
621 case AML_FIELD_UPDATE_WRITE_AS_ONES
:
623 /* Set positions outside the field to all ones */
625 merged_value
|= ~mask
;
628 case AML_FIELD_UPDATE_WRITE_AS_ZEROS
:
630 /* Set positions outside the field to all zeros */
632 merged_value
&= mask
;
638 "Unknown UpdateRule value: %X",
639 (obj_desc
->common_field
.
641 AML_FIELD_UPDATE_RULE_MASK
)));
642 return_ACPI_STATUS(AE_AML_OPERAND_VALUE
);
646 ACPI_DEBUG_PRINT((ACPI_DB_BFIELD
,
647 "Mask %8.8X%8.8X, DatumOffset %X, Width %X, Value %8.8X%8.8X, MergedValue %8.8X%8.8X\n",
648 ACPI_FORMAT_UINT64(mask
),
649 field_datum_byte_offset
,
650 obj_desc
->common_field
.access_byte_width
,
651 ACPI_FORMAT_UINT64(field_value
),
652 ACPI_FORMAT_UINT64(merged_value
)));
654 /* Write the merged value */
656 status
= acpi_ex_field_datum_io(obj_desc
, field_datum_byte_offset
,
657 &merged_value
, ACPI_WRITE
);
659 return_ACPI_STATUS(status
);
662 /*******************************************************************************
664 * FUNCTION: acpi_ex_extract_from_field
666 * PARAMETERS: obj_desc - Field to be read
667 * Buffer - Where to store the field data
668 * buffer_length - Length of Buffer
672 * DESCRIPTION: Retrieve the current value of the given field
674 ******************************************************************************/
677 acpi_ex_extract_from_field(union acpi_operand_object
*obj_desc
,
678 void *buffer
, u32 buffer_length
)
681 acpi_integer raw_datum
;
682 acpi_integer merged_datum
;
683 u32 field_offset
= 0;
684 u32 buffer_offset
= 0;
685 u32 buffer_tail_bits
;
687 u32 field_datum_count
;
690 ACPI_FUNCTION_TRACE(ex_extract_from_field
);
692 /* Validate target buffer and clear it */
695 ACPI_ROUND_BITS_UP_TO_BYTES(obj_desc
->common_field
.bit_length
)) {
697 "Field size %X (bits) is too large for buffer (%X)",
698 obj_desc
->common_field
.bit_length
, buffer_length
));
700 return_ACPI_STATUS(AE_BUFFER_OVERFLOW
);
702 ACPI_MEMSET(buffer
, 0, buffer_length
);
704 /* Compute the number of datums (access width data items) */
706 datum_count
= ACPI_ROUND_UP_TO(obj_desc
->common_field
.bit_length
,
707 obj_desc
->common_field
.access_bit_width
);
708 field_datum_count
= ACPI_ROUND_UP_TO(obj_desc
->common_field
.bit_length
+
709 obj_desc
->common_field
.
710 start_field_bit_offset
,
711 obj_desc
->common_field
.
714 /* Priming read from the field */
717 acpi_ex_field_datum_io(obj_desc
, field_offset
, &raw_datum
,
719 if (ACPI_FAILURE(status
)) {
720 return_ACPI_STATUS(status
);
723 raw_datum
>> obj_desc
->common_field
.start_field_bit_offset
;
725 /* Read the rest of the field */
727 for (i
= 1; i
< field_datum_count
; i
++) {
729 /* Get next input datum from the field */
731 field_offset
+= obj_desc
->common_field
.access_byte_width
;
732 status
= acpi_ex_field_datum_io(obj_desc
, field_offset
,
733 &raw_datum
, ACPI_READ
);
734 if (ACPI_FAILURE(status
)) {
735 return_ACPI_STATUS(status
);
739 * Merge with previous datum if necessary.
741 * Note: Before the shift, check if the shift value will be larger than
742 * the integer size. If so, there is no need to perform the operation.
743 * This avoids the differences in behavior between different compilers
744 * concerning shift values larger than the target data width.
746 if ((obj_desc
->common_field
.access_bit_width
-
747 obj_desc
->common_field
.start_field_bit_offset
) <
748 ACPI_INTEGER_BIT_SIZE
) {
750 raw_datum
<< (obj_desc
->common_field
.
752 obj_desc
->common_field
.
753 start_field_bit_offset
);
756 if (i
== datum_count
) {
760 /* Write merged datum to target buffer */
762 ACPI_MEMCPY(((char *)buffer
) + buffer_offset
, &merged_datum
,
763 ACPI_MIN(obj_desc
->common_field
.access_byte_width
,
764 buffer_length
- buffer_offset
));
766 buffer_offset
+= obj_desc
->common_field
.access_byte_width
;
768 raw_datum
>> obj_desc
->common_field
.start_field_bit_offset
;
771 /* Mask off any extra bits in the last datum */
773 buffer_tail_bits
= obj_desc
->common_field
.bit_length
%
774 obj_desc
->common_field
.access_bit_width
;
775 if (buffer_tail_bits
) {
776 merged_datum
&= ACPI_MASK_BITS_ABOVE(buffer_tail_bits
);
779 /* Write the last datum to the buffer */
781 ACPI_MEMCPY(((char *)buffer
) + buffer_offset
, &merged_datum
,
782 ACPI_MIN(obj_desc
->common_field
.access_byte_width
,
783 buffer_length
- buffer_offset
));
785 return_ACPI_STATUS(AE_OK
);
788 /*******************************************************************************
790 * FUNCTION: acpi_ex_insert_into_field
792 * PARAMETERS: obj_desc - Field to be written
793 * Buffer - Data to be written
794 * buffer_length - Length of Buffer
798 * DESCRIPTION: Store the Buffer contents into the given field
800 ******************************************************************************/
803 acpi_ex_insert_into_field(union acpi_operand_object
*obj_desc
,
804 void *buffer
, u32 buffer_length
)
808 acpi_integer width_mask
;
809 acpi_integer merged_datum
;
810 acpi_integer raw_datum
= 0;
811 u32 field_offset
= 0;
812 u32 buffer_offset
= 0;
813 u32 buffer_tail_bits
;
815 u32 field_datum_count
;
820 ACPI_FUNCTION_TRACE(ex_insert_into_field
);
822 /* Validate input buffer */
826 ACPI_ROUND_BITS_UP_TO_BYTES(obj_desc
->common_field
.bit_length
);
828 * We must have a buffer that is at least as long as the field
829 * we are writing to. This is because individual fields are
830 * indivisible and partial writes are not supported -- as per
831 * the ACPI specification.
833 if (buffer_length
< required_length
) {
835 /* We need to create a new buffer */
837 new_buffer
= ACPI_ALLOCATE_ZEROED(required_length
);
839 return_ACPI_STATUS(AE_NO_MEMORY
);
843 * Copy the original data to the new buffer, starting
844 * at Byte zero. All unused (upper) bytes of the
847 ACPI_MEMCPY((char *)new_buffer
, (char *)buffer
, buffer_length
);
849 buffer_length
= required_length
;
853 * Create the bitmasks used for bit insertion.
854 * Note: This if/else is used to bypass compiler differences with the
857 if (obj_desc
->common_field
.access_bit_width
== ACPI_INTEGER_BIT_SIZE
) {
858 width_mask
= ACPI_INTEGER_MAX
;
861 ACPI_MASK_BITS_ABOVE(obj_desc
->common_field
.
866 ACPI_MASK_BITS_BELOW(obj_desc
->common_field
.start_field_bit_offset
);
868 /* Compute the number of datums (access width data items) */
870 datum_count
= ACPI_ROUND_UP_TO(obj_desc
->common_field
.bit_length
,
871 obj_desc
->common_field
.access_bit_width
);
873 field_datum_count
= ACPI_ROUND_UP_TO(obj_desc
->common_field
.bit_length
+
874 obj_desc
->common_field
.
875 start_field_bit_offset
,
876 obj_desc
->common_field
.
879 /* Get initial Datum from the input buffer */
881 ACPI_MEMCPY(&raw_datum
, buffer
,
882 ACPI_MIN(obj_desc
->common_field
.access_byte_width
,
883 buffer_length
- buffer_offset
));
886 raw_datum
<< obj_desc
->common_field
.start_field_bit_offset
;
888 /* Write the entire field */
890 for (i
= 1; i
< field_datum_count
; i
++) {
892 /* Write merged datum to the target field */
894 merged_datum
&= mask
;
895 status
= acpi_ex_write_with_update_rule(obj_desc
, mask
,
898 if (ACPI_FAILURE(status
)) {
902 field_offset
+= obj_desc
->common_field
.access_byte_width
;
905 * Start new output datum by merging with previous input datum
908 * Note: Before the shift, check if the shift value will be larger than
909 * the integer size. If so, there is no need to perform the operation.
910 * This avoids the differences in behavior between different compilers
911 * concerning shift values larger than the target data width.
913 if ((obj_desc
->common_field
.access_bit_width
-
914 obj_desc
->common_field
.start_field_bit_offset
) <
915 ACPI_INTEGER_BIT_SIZE
) {
917 raw_datum
>> (obj_desc
->common_field
.
919 obj_desc
->common_field
.
920 start_field_bit_offset
);
927 if (i
== datum_count
) {
931 /* Get the next input datum from the buffer */
933 buffer_offset
+= obj_desc
->common_field
.access_byte_width
;
934 ACPI_MEMCPY(&raw_datum
, ((char *)buffer
) + buffer_offset
,
935 ACPI_MIN(obj_desc
->common_field
.access_byte_width
,
936 buffer_length
- buffer_offset
));
938 raw_datum
<< obj_desc
->common_field
.start_field_bit_offset
;
941 /* Mask off any extra bits in the last datum */
943 buffer_tail_bits
= (obj_desc
->common_field
.bit_length
+
944 obj_desc
->common_field
.start_field_bit_offset
) %
945 obj_desc
->common_field
.access_bit_width
;
946 if (buffer_tail_bits
) {
947 mask
&= ACPI_MASK_BITS_ABOVE(buffer_tail_bits
);
950 /* Write the last datum to the field */
952 merged_datum
&= mask
;
953 status
= acpi_ex_write_with_update_rule(obj_desc
,
958 /* Free temporary buffer if we used one */
961 ACPI_FREE(new_buffer
);
963 return_ACPI_STATUS(status
);