1 /******************************************************************************
3 * Module Name: exfldio - Aml Field I/O
5 *****************************************************************************/
8 * Copyright (C) 2000 - 2008, 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
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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);
117 * Exit now for SMBus address space, it has a non-linear address space
118 * and the request cannot be directly validated
120 if (rgn_desc->region.space_id == ACPI_ADR_SPACE_SMBUS) {
122 /* SMBus has a non-linear address space */
124 return_ACPI_STATUS(AE_OK);
126 #ifdef ACPI_UNDER_DEVELOPMENT
128 * If the Field access is any_acc, we can now compute the optimal
129 * access (because we know know the length of the parent region)
131 if (!(obj_desc->common.flags & AOPOBJ_DATA_VALID)) {
132 if (ACPI_FAILURE(status)) {
133 return_ACPI_STATUS(status);
139 * Validate the request. The entire request from the byte offset for a
140 * length of one field datum (access width) must fit within the region.
141 * (Region length is specified in bytes)
143 if (rgn_desc->region.length <
144 (obj_desc->common_field.base_byte_offset +
145 field_datum_byte_offset +
146 obj_desc->common_field.access_byte_width)) {
147 if (acpi_gbl_enable_interpreter_slack) {
149 * Slack mode only: We will go ahead and allow access to this
150 * field if it is within the region length rounded up to the next
151 * access width boundary. acpi_size cast for 64-bit compile.
153 if (ACPI_ROUND_UP(rgn_desc->region.length,
154 obj_desc->common_field.
155 access_byte_width) >=
156 ((acpi_size) obj_desc->common_field.
158 obj_desc->common_field.access_byte_width +
159 field_datum_byte_offset)) {
160 return_ACPI_STATUS(AE_OK);
164 if (rgn_desc->region.length <
165 obj_desc->common_field.access_byte_width) {
167 * This is the case where the access_type (acc_word, etc.) is wider
168 * than the region itself. For example, a region of length one
169 * byte, and a field with Dword access specified.
172 "Field [%4.4s] access width (%d bytes) too large for region [%4.4s] (length %X)",
173 acpi_ut_get_node_name(obj_desc->
175 obj_desc->common_field.access_byte_width,
176 acpi_ut_get_node_name(rgn_desc->region.
178 rgn_desc->region.length));
182 * Offset rounded up to next multiple of field width
183 * exceeds region length, indicate an error
186 "Field [%4.4s] Base+Offset+Width %X+%X+%X is beyond end of region [%4.4s] (length %X)",
187 acpi_ut_get_node_name(obj_desc->common_field.node),
188 obj_desc->common_field.base_byte_offset,
189 field_datum_byte_offset,
190 obj_desc->common_field.access_byte_width,
191 acpi_ut_get_node_name(rgn_desc->region.node),
192 rgn_desc->region.length));
194 return_ACPI_STATUS(AE_AML_REGION_LIMIT);
197 return_ACPI_STATUS(AE_OK);
200 /*******************************************************************************
202 * FUNCTION: acpi_ex_access_region
204 * PARAMETERS: obj_desc - Field to be read
205 * field_datum_byte_offset - Byte offset of this datum within the
207 * Value - Where to store value (must at least
208 * the size of acpi_integer)
209 * Function - Read or Write flag plus other region-
214 * DESCRIPTION: Read or Write a single field datum to an Operation Region.
216 ******************************************************************************/
219 acpi_ex_access_region(union acpi_operand_object *obj_desc,
220 u32 field_datum_byte_offset,
221 acpi_integer * value, u32 function)
224 union acpi_operand_object *rgn_desc;
225 acpi_physical_address address;
227 ACPI_FUNCTION_TRACE(ex_access_region);
230 * Ensure that the region operands are fully evaluated and verify
231 * the validity of the request
233 status = acpi_ex_setup_region(obj_desc, field_datum_byte_offset);
234 if (ACPI_FAILURE(status)) {
235 return_ACPI_STATUS(status);
239 * The physical address of this field datum is:
241 * 1) The base of the region, plus
242 * 2) The base offset of the field, plus
243 * 3) The current offset into the field
245 rgn_desc = obj_desc->common_field.region_obj;
246 address = rgn_desc->region.address +
247 obj_desc->common_field.base_byte_offset + field_datum_byte_offset;
249 if ((function & ACPI_IO_MASK) == ACPI_READ) {
250 ACPI_DEBUG_PRINT((ACPI_DB_BFIELD, "[READ]"));
252 ACPI_DEBUG_PRINT((ACPI_DB_BFIELD, "[WRITE]"));
255 ACPI_DEBUG_PRINT_RAW((ACPI_DB_BFIELD,
256 " Region [%s:%X], Width %X, ByteBase %X, Offset %X at %p\n",
257 acpi_ut_get_region_name(rgn_desc->region.
259 rgn_desc->region.space_id,
260 obj_desc->common_field.access_byte_width,
261 obj_desc->common_field.base_byte_offset,
262 field_datum_byte_offset, ACPI_CAST_PTR(void,
265 /* Invoke the appropriate address_space/op_region handler */
267 status = acpi_ev_address_space_dispatch(rgn_desc, function,
269 ACPI_MUL_8(obj_desc->
274 if (ACPI_FAILURE(status)) {
275 if (status == AE_NOT_IMPLEMENTED) {
277 "Region %s(%X) not implemented",
278 acpi_ut_get_region_name(rgn_desc->region.
280 rgn_desc->region.space_id));
281 } else if (status == AE_NOT_EXIST) {
283 "Region %s(%X) has no handler",
284 acpi_ut_get_region_name(rgn_desc->region.
286 rgn_desc->region.space_id));
290 return_ACPI_STATUS(status);
293 /*******************************************************************************
295 * FUNCTION: acpi_ex_register_overflow
297 * PARAMETERS: obj_desc - Register(Field) to be written
298 * Value - Value to be stored
300 * RETURN: TRUE if value overflows the field, FALSE otherwise
302 * DESCRIPTION: Check if a value is out of range of the field being written.
303 * Used to check if the values written to Index and Bank registers
304 * are out of range. Normally, the value is simply truncated
305 * to fit the field, but this case is most likely a serious
306 * coding error in the ASL.
308 ******************************************************************************/
311 acpi_ex_register_overflow(union acpi_operand_object *obj_desc,
315 if (obj_desc->common_field.bit_length >= ACPI_INTEGER_BIT_SIZE) {
317 * The field is large enough to hold the maximum integer, so we can
323 if (value >= ((acpi_integer) 1 << obj_desc->common_field.bit_length)) {
325 * The Value is larger than the maximum value that can fit into
331 /* The Value will fit into the field with no truncation */
336 /*******************************************************************************
338 * FUNCTION: acpi_ex_field_datum_io
340 * PARAMETERS: obj_desc - Field to be read
341 * field_datum_byte_offset - Byte offset of this datum within the
343 * Value - Where to store value (must be 64 bits)
344 * read_write - Read or Write flag
348 * DESCRIPTION: Read or Write a single datum of a field. The field_type is
349 * demultiplexed here to handle the different types of fields
350 * (buffer_field, region_field, index_field, bank_field)
352 ******************************************************************************/
355 acpi_ex_field_datum_io(union acpi_operand_object *obj_desc,
356 u32 field_datum_byte_offset,
357 acpi_integer * value, u32 read_write)
360 acpi_integer local_value;
362 ACPI_FUNCTION_TRACE_U32(ex_field_datum_io, field_datum_byte_offset);
364 if (read_write == ACPI_READ) {
368 /* To support reads without saving return value */
369 value = &local_value;
372 /* Clear the entire return buffer first, [Very Important!] */
378 * The four types of fields are:
380 * buffer_field - Read/write from/to a Buffer
381 * region_field - Read/write from/to a Operation Region.
382 * bank_field - Write to a Bank Register, then read/write from/to an
384 * index_field - Write to an Index Register, then read/write from/to a
387 switch (obj_desc->common.type) {
388 case ACPI_TYPE_BUFFER_FIELD:
390 * If the buffer_field arguments have not been previously evaluated,
391 * evaluate them now and save the results.
393 if (!(obj_desc->common.flags & AOPOBJ_DATA_VALID)) {
394 status = acpi_ds_get_buffer_field_arguments(obj_desc);
395 if (ACPI_FAILURE(status)) {
396 return_ACPI_STATUS(status);
400 if (read_write == ACPI_READ) {
402 * Copy the data from the source buffer.
403 * Length is the field width in bytes.
406 (obj_desc->buffer_field.buffer_obj)->buffer.
408 obj_desc->buffer_field.base_byte_offset +
409 field_datum_byte_offset,
410 obj_desc->common_field.access_byte_width);
413 * Copy the data to the target buffer.
414 * Length is the field width in bytes.
416 ACPI_MEMCPY((obj_desc->buffer_field.buffer_obj)->buffer.
418 obj_desc->buffer_field.base_byte_offset +
419 field_datum_byte_offset, value,
420 obj_desc->common_field.access_byte_width);
426 case ACPI_TYPE_LOCAL_BANK_FIELD:
429 * Ensure that the bank_value is not beyond the capacity of
432 if (acpi_ex_register_overflow(obj_desc->bank_field.bank_obj,
433 (acpi_integer) obj_desc->
435 return_ACPI_STATUS(AE_AML_REGISTER_LIMIT);
439 * For bank_fields, we must write the bank_value to the bank_register
440 * (itself a region_field) before we can access the data.
443 acpi_ex_insert_into_field(obj_desc->bank_field.bank_obj,
444 &obj_desc->bank_field.value,
445 sizeof(obj_desc->bank_field.
447 if (ACPI_FAILURE(status)) {
448 return_ACPI_STATUS(status);
452 * Now that the Bank has been selected, fall through to the
453 * region_field case and write the datum to the Operation Region
456 /*lint -fallthrough */
458 case ACPI_TYPE_LOCAL_REGION_FIELD:
460 * For simple region_fields, we just directly access the owning
464 acpi_ex_access_region(obj_desc, field_datum_byte_offset,
468 case ACPI_TYPE_LOCAL_INDEX_FIELD:
471 * Ensure that the index_value is not beyond the capacity of
474 if (acpi_ex_register_overflow(obj_desc->index_field.index_obj,
475 (acpi_integer) obj_desc->
476 index_field.value)) {
477 return_ACPI_STATUS(AE_AML_REGISTER_LIMIT);
480 /* Write the index value to the index_register (itself a region_field) */
482 field_datum_byte_offset += obj_desc->index_field.value;
484 ACPI_DEBUG_PRINT((ACPI_DB_BFIELD,
485 "Write to Index Register: Value %8.8X\n",
486 field_datum_byte_offset));
489 acpi_ex_insert_into_field(obj_desc->index_field.index_obj,
490 &field_datum_byte_offset,
491 sizeof(field_datum_byte_offset));
492 if (ACPI_FAILURE(status)) {
493 return_ACPI_STATUS(status);
496 if (read_write == ACPI_READ) {
498 /* Read the datum from the data_register */
500 ACPI_DEBUG_PRINT((ACPI_DB_BFIELD,
501 "Read from Data Register\n"));
504 acpi_ex_extract_from_field(obj_desc->index_field.
506 sizeof(acpi_integer));
508 /* Write the datum to the data_register */
510 ACPI_DEBUG_PRINT((ACPI_DB_BFIELD,
511 "Write to Data Register: Value %8.8X%8.8X\n",
512 ACPI_FORMAT_UINT64(*value)));
515 acpi_ex_insert_into_field(obj_desc->index_field.
517 sizeof(acpi_integer));
523 ACPI_ERROR((AE_INFO, "Wrong object type in field I/O %X",
524 obj_desc->common.type));
525 status = AE_AML_INTERNAL;
529 if (ACPI_SUCCESS(status)) {
530 if (read_write == ACPI_READ) {
531 ACPI_DEBUG_PRINT((ACPI_DB_BFIELD,
532 "Value Read %8.8X%8.8X, Width %d\n",
533 ACPI_FORMAT_UINT64(*value),
534 obj_desc->common_field.
537 ACPI_DEBUG_PRINT((ACPI_DB_BFIELD,
538 "Value Written %8.8X%8.8X, Width %d\n",
539 ACPI_FORMAT_UINT64(*value),
540 obj_desc->common_field.
545 return_ACPI_STATUS(status);
548 /*******************************************************************************
550 * FUNCTION: acpi_ex_write_with_update_rule
552 * PARAMETERS: obj_desc - Field to be written
553 * Mask - bitmask within field datum
554 * field_value - Value to write
555 * field_datum_byte_offset - Offset of datum within field
559 * DESCRIPTION: Apply the field update rule to a field write
561 ******************************************************************************/
564 acpi_ex_write_with_update_rule(union acpi_operand_object *obj_desc,
566 acpi_integer field_value,
567 u32 field_datum_byte_offset)
569 acpi_status status = AE_OK;
570 acpi_integer merged_value;
571 acpi_integer current_value;
573 ACPI_FUNCTION_TRACE_U32(ex_write_with_update_rule, mask);
575 /* Start with the new bits */
577 merged_value = field_value;
579 /* If the mask is all ones, we don't need to worry about the update rule */
581 if (mask != ACPI_INTEGER_MAX) {
583 /* Decode the update rule */
585 switch (obj_desc->common_field.
586 field_flags & AML_FIELD_UPDATE_RULE_MASK) {
587 case AML_FIELD_UPDATE_PRESERVE:
589 * Check if update rule needs to be applied (not if mask is all
590 * ones) The left shift drops the bits we want to ignore.
592 if ((~mask << (ACPI_MUL_8(sizeof(mask)) -
593 ACPI_MUL_8(obj_desc->common_field.
594 access_byte_width))) != 0) {
596 * Read the current contents of the byte/word/dword containing
597 * the field, and merge with the new field value.
600 acpi_ex_field_datum_io(obj_desc,
601 field_datum_byte_offset,
604 if (ACPI_FAILURE(status)) {
605 return_ACPI_STATUS(status);
608 merged_value |= (current_value & ~mask);
612 case AML_FIELD_UPDATE_WRITE_AS_ONES:
614 /* Set positions outside the field to all ones */
616 merged_value |= ~mask;
619 case AML_FIELD_UPDATE_WRITE_AS_ZEROS:
621 /* Set positions outside the field to all zeros */
623 merged_value &= mask;
629 "Unknown UpdateRule value: %X",
630 (obj_desc->common_field.
632 AML_FIELD_UPDATE_RULE_MASK)));
633 return_ACPI_STATUS(AE_AML_OPERAND_VALUE);
637 ACPI_DEBUG_PRINT((ACPI_DB_BFIELD,
638 "Mask %8.8X%8.8X, DatumOffset %X, Width %X, Value %8.8X%8.8X, MergedValue %8.8X%8.8X\n",
639 ACPI_FORMAT_UINT64(mask),
640 field_datum_byte_offset,
641 obj_desc->common_field.access_byte_width,
642 ACPI_FORMAT_UINT64(field_value),
643 ACPI_FORMAT_UINT64(merged_value)));
645 /* Write the merged value */
647 status = acpi_ex_field_datum_io(obj_desc, field_datum_byte_offset,
648 &merged_value, ACPI_WRITE);
650 return_ACPI_STATUS(status);
653 /*******************************************************************************
655 * FUNCTION: acpi_ex_extract_from_field
657 * PARAMETERS: obj_desc - Field to be read
658 * Buffer - Where to store the field data
659 * buffer_length - Length of Buffer
663 * DESCRIPTION: Retrieve the current value of the given field
665 ******************************************************************************/
668 acpi_ex_extract_from_field(union acpi_operand_object *obj_desc,
669 void *buffer, u32 buffer_length)
672 acpi_integer raw_datum;
673 acpi_integer merged_datum;
674 u32 field_offset = 0;
675 u32 buffer_offset = 0;
676 u32 buffer_tail_bits;
678 u32 field_datum_count;
681 ACPI_FUNCTION_TRACE(ex_extract_from_field);
683 /* Validate target buffer and clear it */
686 ACPI_ROUND_BITS_UP_TO_BYTES(obj_desc->common_field.bit_length)) {
688 "Field size %X (bits) is too large for buffer (%X)",
689 obj_desc->common_field.bit_length, buffer_length));
691 return_ACPI_STATUS(AE_BUFFER_OVERFLOW);
693 ACPI_MEMSET(buffer, 0, buffer_length);
695 /* Compute the number of datums (access width data items) */
697 datum_count = ACPI_ROUND_UP_TO(obj_desc->common_field.bit_length,
698 obj_desc->common_field.access_bit_width);
699 field_datum_count = ACPI_ROUND_UP_TO(obj_desc->common_field.bit_length +
700 obj_desc->common_field.
701 start_field_bit_offset,
702 obj_desc->common_field.
705 /* Priming read from the field */
708 acpi_ex_field_datum_io(obj_desc, field_offset, &raw_datum,
710 if (ACPI_FAILURE(status)) {
711 return_ACPI_STATUS(status);
714 raw_datum >> obj_desc->common_field.start_field_bit_offset;
716 /* Read the rest of the field */
718 for (i = 1; i < field_datum_count; i++) {
720 /* Get next input datum from the field */
722 field_offset += obj_desc->common_field.access_byte_width;
723 status = acpi_ex_field_datum_io(obj_desc, field_offset,
724 &raw_datum, ACPI_READ);
725 if (ACPI_FAILURE(status)) {
726 return_ACPI_STATUS(status);
730 * Merge with previous datum if necessary.
732 * Note: Before the shift, check if the shift value will be larger than
733 * the integer size. If so, there is no need to perform the operation.
734 * This avoids the differences in behavior between different compilers
735 * concerning shift values larger than the target data width.
737 if ((obj_desc->common_field.access_bit_width -
738 obj_desc->common_field.start_field_bit_offset) <
739 ACPI_INTEGER_BIT_SIZE) {
741 raw_datum << (obj_desc->common_field.
743 obj_desc->common_field.
744 start_field_bit_offset);
747 if (i == datum_count) {
751 /* Write merged datum to target buffer */
753 ACPI_MEMCPY(((char *)buffer) + buffer_offset, &merged_datum,
754 ACPI_MIN(obj_desc->common_field.access_byte_width,
755 buffer_length - buffer_offset));
757 buffer_offset += obj_desc->common_field.access_byte_width;
759 raw_datum >> obj_desc->common_field.start_field_bit_offset;
762 /* Mask off any extra bits in the last datum */
764 buffer_tail_bits = obj_desc->common_field.bit_length %
765 obj_desc->common_field.access_bit_width;
766 if (buffer_tail_bits) {
767 merged_datum &= ACPI_MASK_BITS_ABOVE(buffer_tail_bits);
770 /* Write the last datum to the buffer */
772 ACPI_MEMCPY(((char *)buffer) + buffer_offset, &merged_datum,
773 ACPI_MIN(obj_desc->common_field.access_byte_width,
774 buffer_length - buffer_offset));
776 return_ACPI_STATUS(AE_OK);
779 /*******************************************************************************
781 * FUNCTION: acpi_ex_insert_into_field
783 * PARAMETERS: obj_desc - Field to be written
784 * Buffer - Data to be written
785 * buffer_length - Length of Buffer
789 * DESCRIPTION: Store the Buffer contents into the given field
791 ******************************************************************************/
794 acpi_ex_insert_into_field(union acpi_operand_object *obj_desc,
795 void *buffer, u32 buffer_length)
799 acpi_integer width_mask;
800 acpi_integer merged_datum;
801 acpi_integer raw_datum = 0;
802 u32 field_offset = 0;
803 u32 buffer_offset = 0;
804 u32 buffer_tail_bits;
806 u32 field_datum_count;
811 ACPI_FUNCTION_TRACE(ex_insert_into_field);
813 /* Validate input buffer */
817 ACPI_ROUND_BITS_UP_TO_BYTES(obj_desc->common_field.bit_length);
819 * We must have a buffer that is at least as long as the field
820 * we are writing to. This is because individual fields are
821 * indivisible and partial writes are not supported -- as per
822 * the ACPI specification.
824 if (buffer_length < required_length) {
826 /* We need to create a new buffer */
828 new_buffer = ACPI_ALLOCATE_ZEROED(required_length);
830 return_ACPI_STATUS(AE_NO_MEMORY);
834 * Copy the original data to the new buffer, starting
835 * at Byte zero. All unused (upper) bytes of the
838 ACPI_MEMCPY((char *)new_buffer, (char *)buffer, buffer_length);
840 buffer_length = required_length;
844 * Create the bitmasks used for bit insertion.
845 * Note: This if/else is used to bypass compiler differences with the
848 if (obj_desc->common_field.access_bit_width == ACPI_INTEGER_BIT_SIZE) {
849 width_mask = ACPI_INTEGER_MAX;
852 ACPI_MASK_BITS_ABOVE(obj_desc->common_field.
857 ACPI_MASK_BITS_BELOW(obj_desc->common_field.start_field_bit_offset);
859 /* Compute the number of datums (access width data items) */
861 datum_count = ACPI_ROUND_UP_TO(obj_desc->common_field.bit_length,
862 obj_desc->common_field.access_bit_width);
864 field_datum_count = ACPI_ROUND_UP_TO(obj_desc->common_field.bit_length +
865 obj_desc->common_field.
866 start_field_bit_offset,
867 obj_desc->common_field.
870 /* Get initial Datum from the input buffer */
872 ACPI_MEMCPY(&raw_datum, buffer,
873 ACPI_MIN(obj_desc->common_field.access_byte_width,
874 buffer_length - buffer_offset));
877 raw_datum << obj_desc->common_field.start_field_bit_offset;
879 /* Write the entire field */
881 for (i = 1; i < field_datum_count; i++) {
883 /* Write merged datum to the target field */
885 merged_datum &= mask;
886 status = acpi_ex_write_with_update_rule(obj_desc, mask,
889 if (ACPI_FAILURE(status)) {
893 field_offset += obj_desc->common_field.access_byte_width;
896 * Start new output datum by merging with previous input datum
899 * Note: Before the shift, check if the shift value will be larger than
900 * the integer size. If so, there is no need to perform the operation.
901 * This avoids the differences in behavior between different compilers
902 * concerning shift values larger than the target data width.
904 if ((obj_desc->common_field.access_bit_width -
905 obj_desc->common_field.start_field_bit_offset) <
906 ACPI_INTEGER_BIT_SIZE) {
908 raw_datum >> (obj_desc->common_field.
910 obj_desc->common_field.
911 start_field_bit_offset);
918 if (i == datum_count) {
922 /* Get the next input datum from the buffer */
924 buffer_offset += obj_desc->common_field.access_byte_width;
925 ACPI_MEMCPY(&raw_datum, ((char *)buffer) + buffer_offset,
926 ACPI_MIN(obj_desc->common_field.access_byte_width,
927 buffer_length - buffer_offset));
929 raw_datum << obj_desc->common_field.start_field_bit_offset;
932 /* Mask off any extra bits in the last datum */
934 buffer_tail_bits = (obj_desc->common_field.bit_length +
935 obj_desc->common_field.start_field_bit_offset) %
936 obj_desc->common_field.access_bit_width;
937 if (buffer_tail_bits) {
938 mask &= ACPI_MASK_BITS_ABOVE(buffer_tail_bits);
941 /* Write the last datum to the field */
943 merged_datum &= mask;
944 status = acpi_ex_write_with_update_rule(obj_desc,
949 /* Free temporary buffer if we used one */
952 ACPI_FREE(new_buffer);
954 return_ACPI_STATUS(status);