xref: /openbmc/linux/drivers/acpi/acpica/dsopcode.c (revision 2f0754f2)
1 // SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0
2 /******************************************************************************
3  *
4  * Module Name: dsopcode - Dispatcher support for regions and fields
5  *
6  * Copyright (C) 2000 - 2021, Intel Corp.
7  *
8  *****************************************************************************/
9 
10 #include <acpi/acpi.h>
11 #include "accommon.h"
12 #include "acparser.h"
13 #include "amlcode.h"
14 #include "acdispat.h"
15 #include "acinterp.h"
16 #include "acnamesp.h"
17 #include "acevents.h"
18 #include "actables.h"
19 
20 #define _COMPONENT          ACPI_DISPATCHER
21 ACPI_MODULE_NAME("dsopcode")
22 
23 /* Local prototypes */
24 static acpi_status
25 acpi_ds_init_buffer_field(u16 aml_opcode,
26 			  union acpi_operand_object *obj_desc,
27 			  union acpi_operand_object *buffer_desc,
28 			  union acpi_operand_object *offset_desc,
29 			  union acpi_operand_object *length_desc,
30 			  union acpi_operand_object *result_desc);
31 
32 /*******************************************************************************
33  *
34  * FUNCTION:    acpi_ds_initialize_region
35  *
36  * PARAMETERS:  obj_handle      - Region namespace node
37  *
38  * RETURN:      Status
39  *
40  * DESCRIPTION: Front end to ev_initialize_region
41  *
42  ******************************************************************************/
43 
44 acpi_status acpi_ds_initialize_region(acpi_handle obj_handle)
45 {
46 	union acpi_operand_object *obj_desc;
47 	acpi_status status;
48 
49 	obj_desc = acpi_ns_get_attached_object(obj_handle);
50 
51 	/* Namespace is NOT locked */
52 
53 	status = acpi_ev_initialize_region(obj_desc);
54 	return (status);
55 }
56 
57 /*******************************************************************************
58  *
59  * FUNCTION:    acpi_ds_init_buffer_field
60  *
61  * PARAMETERS:  aml_opcode      - create_xxx_field
62  *              obj_desc        - buffer_field object
63  *              buffer_desc     - Host Buffer
64  *              offset_desc     - Offset into buffer
65  *              length_desc     - Length of field (CREATE_FIELD_OP only)
66  *              result_desc     - Where to store the result
67  *
68  * RETURN:      Status
69  *
70  * DESCRIPTION: Perform actual initialization of a buffer field
71  *
72  ******************************************************************************/
73 
74 static acpi_status
75 acpi_ds_init_buffer_field(u16 aml_opcode,
76 			  union acpi_operand_object *obj_desc,
77 			  union acpi_operand_object *buffer_desc,
78 			  union acpi_operand_object *offset_desc,
79 			  union acpi_operand_object *length_desc,
80 			  union acpi_operand_object *result_desc)
81 {
82 	u32 offset;
83 	u32 bit_offset;
84 	u32 bit_count;
85 	u8 field_flags;
86 	acpi_status status;
87 
88 	ACPI_FUNCTION_TRACE_PTR(ds_init_buffer_field, obj_desc);
89 
90 	/* Host object must be a Buffer */
91 
92 	if (buffer_desc->common.type != ACPI_TYPE_BUFFER) {
93 		ACPI_ERROR((AE_INFO,
94 			    "Target of Create Field is not a Buffer object - %s",
95 			    acpi_ut_get_object_type_name(buffer_desc)));
96 
97 		status = AE_AML_OPERAND_TYPE;
98 		goto cleanup;
99 	}
100 
101 	/*
102 	 * The last parameter to all of these opcodes (result_desc) started
103 	 * out as a name_string, and should therefore now be a NS node
104 	 * after resolution in acpi_ex_resolve_operands().
105 	 */
106 	if (ACPI_GET_DESCRIPTOR_TYPE(result_desc) != ACPI_DESC_TYPE_NAMED) {
107 		ACPI_ERROR((AE_INFO,
108 			    "(%s) destination not a NS Node [%s]",
109 			    acpi_ps_get_opcode_name(aml_opcode),
110 			    acpi_ut_get_descriptor_name(result_desc)));
111 
112 		status = AE_AML_OPERAND_TYPE;
113 		goto cleanup;
114 	}
115 
116 	offset = (u32) offset_desc->integer.value;
117 
118 	/*
119 	 * Setup the Bit offsets and counts, according to the opcode
120 	 */
121 	switch (aml_opcode) {
122 	case AML_CREATE_FIELD_OP:
123 
124 		/* Offset is in bits, count is in bits */
125 
126 		field_flags = AML_FIELD_ACCESS_BYTE;
127 		bit_offset = offset;
128 		bit_count = (u32) length_desc->integer.value;
129 
130 		/* Must have a valid (>0) bit count */
131 
132 		if (bit_count == 0) {
133 			ACPI_BIOS_ERROR((AE_INFO,
134 					 "Attempt to CreateField of length zero"));
135 			status = AE_AML_OPERAND_VALUE;
136 			goto cleanup;
137 		}
138 		break;
139 
140 	case AML_CREATE_BIT_FIELD_OP:
141 
142 		/* Offset is in bits, Field is one bit */
143 
144 		bit_offset = offset;
145 		bit_count = 1;
146 		field_flags = AML_FIELD_ACCESS_BYTE;
147 		break;
148 
149 	case AML_CREATE_BYTE_FIELD_OP:
150 
151 		/* Offset is in bytes, field is one byte */
152 
153 		bit_offset = 8 * offset;
154 		bit_count = 8;
155 		field_flags = AML_FIELD_ACCESS_BYTE;
156 		break;
157 
158 	case AML_CREATE_WORD_FIELD_OP:
159 
160 		/* Offset is in bytes, field is one word */
161 
162 		bit_offset = 8 * offset;
163 		bit_count = 16;
164 		field_flags = AML_FIELD_ACCESS_WORD;
165 		break;
166 
167 	case AML_CREATE_DWORD_FIELD_OP:
168 
169 		/* Offset is in bytes, field is one dword */
170 
171 		bit_offset = 8 * offset;
172 		bit_count = 32;
173 		field_flags = AML_FIELD_ACCESS_DWORD;
174 		break;
175 
176 	case AML_CREATE_QWORD_FIELD_OP:
177 
178 		/* Offset is in bytes, field is one qword */
179 
180 		bit_offset = 8 * offset;
181 		bit_count = 64;
182 		field_flags = AML_FIELD_ACCESS_QWORD;
183 		break;
184 
185 	default:
186 
187 		ACPI_ERROR((AE_INFO,
188 			    "Unknown field creation opcode 0x%02X",
189 			    aml_opcode));
190 		status = AE_AML_BAD_OPCODE;
191 		goto cleanup;
192 	}
193 
194 	/* Entire field must fit within the current length of the buffer */
195 
196 	if ((bit_offset + bit_count) > (8 * (u32)buffer_desc->buffer.length)) {
197 		status = AE_AML_BUFFER_LIMIT;
198 		ACPI_BIOS_EXCEPTION((AE_INFO, status,
199 				     "Field [%4.4s] at bit offset/length %u/%u "
200 				     "exceeds size of target Buffer (%u bits)",
201 				     acpi_ut_get_node_name(result_desc),
202 				     bit_offset, bit_count,
203 				     8 * (u32)buffer_desc->buffer.length));
204 		goto cleanup;
205 	}
206 
207 	/*
208 	 * Initialize areas of the field object that are common to all fields
209 	 * For field_flags, use LOCK_RULE = 0 (NO_LOCK),
210 	 * UPDATE_RULE = 0 (UPDATE_PRESERVE)
211 	 */
212 	status =
213 	    acpi_ex_prep_common_field_object(obj_desc, field_flags, 0,
214 					     bit_offset, bit_count);
215 	if (ACPI_FAILURE(status)) {
216 		goto cleanup;
217 	}
218 
219 	obj_desc->buffer_field.buffer_obj = buffer_desc;
220 	obj_desc->buffer_field.is_create_field =
221 	    aml_opcode == AML_CREATE_FIELD_OP;
222 
223 	/* Reference count for buffer_desc inherits obj_desc count */
224 
225 	buffer_desc->common.reference_count = (u16)
226 	    (buffer_desc->common.reference_count +
227 	     obj_desc->common.reference_count);
228 
229 cleanup:
230 
231 	/* Always delete the operands */
232 
233 	acpi_ut_remove_reference(offset_desc);
234 	acpi_ut_remove_reference(buffer_desc);
235 
236 	if (aml_opcode == AML_CREATE_FIELD_OP) {
237 		acpi_ut_remove_reference(length_desc);
238 	}
239 
240 	/* On failure, delete the result descriptor */
241 
242 	if (ACPI_FAILURE(status)) {
243 		acpi_ut_remove_reference(result_desc);	/* Result descriptor */
244 	} else {
245 		/* Now the address and length are valid for this buffer_field */
246 
247 		obj_desc->buffer_field.flags |= AOPOBJ_DATA_VALID;
248 	}
249 
250 	return_ACPI_STATUS(status);
251 }
252 
253 /*******************************************************************************
254  *
255  * FUNCTION:    acpi_ds_eval_buffer_field_operands
256  *
257  * PARAMETERS:  walk_state      - Current walk
258  *              op              - A valid buffer_field Op object
259  *
260  * RETURN:      Status
261  *
262  * DESCRIPTION: Get buffer_field Buffer and Index
263  *              Called from acpi_ds_exec_end_op during buffer_field parse tree walk
264  *
265  ******************************************************************************/
266 
267 acpi_status
268 acpi_ds_eval_buffer_field_operands(struct acpi_walk_state *walk_state,
269 				   union acpi_parse_object *op)
270 {
271 	acpi_status status;
272 	union acpi_operand_object *obj_desc;
273 	struct acpi_namespace_node *node;
274 	union acpi_parse_object *next_op;
275 
276 	ACPI_FUNCTION_TRACE_PTR(ds_eval_buffer_field_operands, op);
277 
278 	/*
279 	 * This is where we evaluate the address and length fields of the
280 	 * create_xxx_field declaration
281 	 */
282 	node = op->common.node;
283 
284 	/* next_op points to the op that holds the Buffer */
285 
286 	next_op = op->common.value.arg;
287 
288 	/* Evaluate/create the address and length operands */
289 
290 	status = acpi_ds_create_operands(walk_state, next_op);
291 	if (ACPI_FAILURE(status)) {
292 		return_ACPI_STATUS(status);
293 	}
294 
295 	obj_desc = acpi_ns_get_attached_object(node);
296 	if (!obj_desc) {
297 		return_ACPI_STATUS(AE_NOT_EXIST);
298 	}
299 
300 	/* Resolve the operands */
301 
302 	status =
303 	    acpi_ex_resolve_operands(op->common.aml_opcode, ACPI_WALK_OPERANDS,
304 				     walk_state);
305 	if (ACPI_FAILURE(status)) {
306 		ACPI_ERROR((AE_INFO, "(%s) bad operand(s), status 0x%X",
307 			    acpi_ps_get_opcode_name(op->common.aml_opcode),
308 			    status));
309 
310 		return_ACPI_STATUS(status);
311 	}
312 
313 	/* Initialize the Buffer Field */
314 
315 	if (op->common.aml_opcode == AML_CREATE_FIELD_OP) {
316 
317 		/* NOTE: Slightly different operands for this opcode */
318 
319 		status =
320 		    acpi_ds_init_buffer_field(op->common.aml_opcode, obj_desc,
321 					      walk_state->operands[0],
322 					      walk_state->operands[1],
323 					      walk_state->operands[2],
324 					      walk_state->operands[3]);
325 	} else {
326 		/* All other, create_xxx_field opcodes */
327 
328 		status =
329 		    acpi_ds_init_buffer_field(op->common.aml_opcode, obj_desc,
330 					      walk_state->operands[0],
331 					      walk_state->operands[1], NULL,
332 					      walk_state->operands[2]);
333 	}
334 
335 	return_ACPI_STATUS(status);
336 }
337 
338 /*******************************************************************************
339  *
340  * FUNCTION:    acpi_ds_eval_region_operands
341  *
342  * PARAMETERS:  walk_state      - Current walk
343  *              op              - A valid region Op object
344  *
345  * RETURN:      Status
346  *
347  * DESCRIPTION: Get region address and length
348  *              Called from acpi_ds_exec_end_op during op_region parse tree walk
349  *
350  ******************************************************************************/
351 
352 acpi_status
353 acpi_ds_eval_region_operands(struct acpi_walk_state *walk_state,
354 			     union acpi_parse_object *op)
355 {
356 	acpi_status status;
357 	union acpi_operand_object *obj_desc;
358 	union acpi_operand_object *operand_desc;
359 	struct acpi_namespace_node *node;
360 	union acpi_parse_object *next_op;
361 	acpi_adr_space_type space_id;
362 
363 	ACPI_FUNCTION_TRACE_PTR(ds_eval_region_operands, op);
364 
365 	/*
366 	 * This is where we evaluate the address and length fields of the
367 	 * op_region declaration
368 	 */
369 	node = op->common.node;
370 
371 	/* next_op points to the op that holds the space_ID */
372 
373 	next_op = op->common.value.arg;
374 	space_id = (acpi_adr_space_type)next_op->common.value.integer;
375 
376 	/* next_op points to address op */
377 
378 	next_op = next_op->common.next;
379 
380 	/* Evaluate/create the address and length operands */
381 
382 	status = acpi_ds_create_operands(walk_state, next_op);
383 	if (ACPI_FAILURE(status)) {
384 		return_ACPI_STATUS(status);
385 	}
386 
387 	/* Resolve the length and address operands to numbers */
388 
389 	status =
390 	    acpi_ex_resolve_operands(op->common.aml_opcode, ACPI_WALK_OPERANDS,
391 				     walk_state);
392 	if (ACPI_FAILURE(status)) {
393 		return_ACPI_STATUS(status);
394 	}
395 
396 	obj_desc = acpi_ns_get_attached_object(node);
397 	if (!obj_desc) {
398 		return_ACPI_STATUS(AE_NOT_EXIST);
399 	}
400 
401 	/*
402 	 * Get the length operand and save it
403 	 * (at Top of stack)
404 	 */
405 	operand_desc = walk_state->operands[walk_state->num_operands - 1];
406 
407 	obj_desc->region.length = (u32) operand_desc->integer.value;
408 	acpi_ut_remove_reference(operand_desc);
409 
410 	/* A zero-length operation region is unusable. Just warn */
411 
412 	if (!obj_desc->region.length
413 	    && (space_id < ACPI_NUM_PREDEFINED_REGIONS)) {
414 		ACPI_WARNING((AE_INFO,
415 			      "Operation Region [%4.4s] has zero length (SpaceId %X)",
416 			      node->name.ascii, space_id));
417 	}
418 
419 	/*
420 	 * Get the address and save it
421 	 * (at top of stack - 1)
422 	 */
423 	operand_desc = walk_state->operands[walk_state->num_operands - 2];
424 
425 	obj_desc->region.address = (acpi_physical_address)
426 	    operand_desc->integer.value;
427 	acpi_ut_remove_reference(operand_desc);
428 
429 	ACPI_DEBUG_PRINT((ACPI_DB_EXEC, "RgnObj %p Addr %8.8X%8.8X Len %X\n",
430 			  obj_desc,
431 			  ACPI_FORMAT_UINT64(obj_desc->region.address),
432 			  obj_desc->region.length));
433 
434 	status = acpi_ut_add_address_range(obj_desc->region.space_id,
435 					   obj_desc->region.address,
436 					   obj_desc->region.length, node);
437 
438 	/* Now the address and length are valid for this opregion */
439 
440 	obj_desc->region.flags |= AOPOBJ_DATA_VALID;
441 	return_ACPI_STATUS(status);
442 }
443 
444 /*******************************************************************************
445  *
446  * FUNCTION:    acpi_ds_eval_table_region_operands
447  *
448  * PARAMETERS:  walk_state      - Current walk
449  *              op              - A valid region Op object
450  *
451  * RETURN:      Status
452  *
453  * DESCRIPTION: Get region address and length.
454  *              Called from acpi_ds_exec_end_op during data_table_region parse
455  *              tree walk.
456  *
457  ******************************************************************************/
458 
459 acpi_status
460 acpi_ds_eval_table_region_operands(struct acpi_walk_state *walk_state,
461 				   union acpi_parse_object *op)
462 {
463 	acpi_status status;
464 	union acpi_operand_object *obj_desc;
465 	union acpi_operand_object **operand;
466 	struct acpi_namespace_node *node;
467 	union acpi_parse_object *next_op;
468 	struct acpi_table_header *table;
469 	u32 table_index;
470 
471 	ACPI_FUNCTION_TRACE_PTR(ds_eval_table_region_operands, op);
472 
473 	/*
474 	 * This is where we evaluate the Signature string, oem_id string,
475 	 * and oem_table_id string of the Data Table Region declaration
476 	 */
477 	node = op->common.node;
478 
479 	/* next_op points to Signature string op */
480 
481 	next_op = op->common.value.arg;
482 
483 	/*
484 	 * Evaluate/create the Signature string, oem_id string,
485 	 * and oem_table_id string operands
486 	 */
487 	status = acpi_ds_create_operands(walk_state, next_op);
488 	if (ACPI_FAILURE(status)) {
489 		return_ACPI_STATUS(status);
490 	}
491 
492 	operand = &walk_state->operands[0];
493 
494 	/*
495 	 * Resolve the Signature string, oem_id string,
496 	 * and oem_table_id string operands
497 	 */
498 	status =
499 	    acpi_ex_resolve_operands(op->common.aml_opcode, ACPI_WALK_OPERANDS,
500 				     walk_state);
501 	if (ACPI_FAILURE(status)) {
502 		goto cleanup;
503 	}
504 
505 	/* Find the ACPI table */
506 
507 	status = acpi_tb_find_table(operand[0]->string.pointer,
508 				    operand[1]->string.pointer,
509 				    operand[2]->string.pointer, &table_index);
510 	if (ACPI_FAILURE(status)) {
511 		if (status == AE_NOT_FOUND) {
512 			ACPI_ERROR((AE_INFO,
513 				    "ACPI Table [%4.4s] OEM:(%s, %s) not found in RSDT/XSDT",
514 				    operand[0]->string.pointer,
515 				    operand[1]->string.pointer,
516 				    operand[2]->string.pointer));
517 		}
518 		goto cleanup;
519 	}
520 
521 	status = acpi_get_table_by_index(table_index, &table);
522 	if (ACPI_FAILURE(status)) {
523 		goto cleanup;
524 	}
525 
526 	obj_desc = acpi_ns_get_attached_object(node);
527 	if (!obj_desc) {
528 		status = AE_NOT_EXIST;
529 		goto cleanup;
530 	}
531 
532 	obj_desc->region.address = ACPI_PTR_TO_PHYSADDR(table);
533 	obj_desc->region.length = table->length;
534 	obj_desc->region.pointer = table;
535 
536 	ACPI_DEBUG_PRINT((ACPI_DB_EXEC, "RgnObj %p Addr %8.8X%8.8X Len %X\n",
537 			  obj_desc,
538 			  ACPI_FORMAT_UINT64(obj_desc->region.address),
539 			  obj_desc->region.length));
540 
541 	/* Now the address and length are valid for this opregion */
542 
543 	obj_desc->region.flags |= AOPOBJ_DATA_VALID;
544 
545 cleanup:
546 	acpi_ut_remove_reference(operand[0]);
547 	acpi_ut_remove_reference(operand[1]);
548 	acpi_ut_remove_reference(operand[2]);
549 
550 	return_ACPI_STATUS(status);
551 }
552 
553 /*******************************************************************************
554  *
555  * FUNCTION:    acpi_ds_eval_data_object_operands
556  *
557  * PARAMETERS:  walk_state      - Current walk
558  *              op              - A valid data_object Op object
559  *              obj_desc        - data_object
560  *
561  * RETURN:      Status
562  *
563  * DESCRIPTION: Get the operands and complete the following data object types:
564  *              Buffer, Package.
565  *
566  ******************************************************************************/
567 
568 acpi_status
569 acpi_ds_eval_data_object_operands(struct acpi_walk_state *walk_state,
570 				  union acpi_parse_object *op,
571 				  union acpi_operand_object *obj_desc)
572 {
573 	acpi_status status;
574 	union acpi_operand_object *arg_desc;
575 	u32 length;
576 
577 	ACPI_FUNCTION_TRACE(ds_eval_data_object_operands);
578 
579 	/* The first operand (for all of these data objects) is the length */
580 
581 	/*
582 	 * Set proper index into operand stack for acpi_ds_obj_stack_push
583 	 * invoked inside acpi_ds_create_operand.
584 	 */
585 	walk_state->operand_index = walk_state->num_operands;
586 
587 	/* Ignore if child is not valid */
588 
589 	if (!op->common.value.arg) {
590 		ACPI_ERROR((AE_INFO,
591 			    "Missing child while evaluating opcode %4.4X, Op %p",
592 			    op->common.aml_opcode, op));
593 		return_ACPI_STATUS(AE_OK);
594 	}
595 
596 	status = acpi_ds_create_operand(walk_state, op->common.value.arg, 1);
597 	if (ACPI_FAILURE(status)) {
598 		return_ACPI_STATUS(status);
599 	}
600 
601 	status = acpi_ex_resolve_operands(walk_state->opcode,
602 					  &(walk_state->
603 					    operands[walk_state->num_operands -
604 						     1]), walk_state);
605 	if (ACPI_FAILURE(status)) {
606 		return_ACPI_STATUS(status);
607 	}
608 
609 	/* Extract length operand */
610 
611 	arg_desc = walk_state->operands[walk_state->num_operands - 1];
612 	length = (u32) arg_desc->integer.value;
613 
614 	/* Cleanup for length operand */
615 
616 	status = acpi_ds_obj_stack_pop(1, walk_state);
617 	if (ACPI_FAILURE(status)) {
618 		return_ACPI_STATUS(status);
619 	}
620 
621 	acpi_ut_remove_reference(arg_desc);
622 
623 	/*
624 	 * Create the actual data object
625 	 */
626 	switch (op->common.aml_opcode) {
627 	case AML_BUFFER_OP:
628 
629 		status =
630 		    acpi_ds_build_internal_buffer_obj(walk_state, op, length,
631 						      &obj_desc);
632 		break;
633 
634 	case AML_PACKAGE_OP:
635 	case AML_VARIABLE_PACKAGE_OP:
636 
637 		status =
638 		    acpi_ds_build_internal_package_obj(walk_state, op, length,
639 						       &obj_desc);
640 		break;
641 
642 	default:
643 
644 		return_ACPI_STATUS(AE_AML_BAD_OPCODE);
645 	}
646 
647 	if (ACPI_SUCCESS(status)) {
648 		/*
649 		 * Return the object in the walk_state, unless the parent is a package -
650 		 * in this case, the return object will be stored in the parse tree
651 		 * for the package.
652 		 */
653 		if ((!op->common.parent) ||
654 		    ((op->common.parent->common.aml_opcode != AML_PACKAGE_OP) &&
655 		     (op->common.parent->common.aml_opcode !=
656 		      AML_VARIABLE_PACKAGE_OP)
657 		     && (op->common.parent->common.aml_opcode !=
658 			 AML_NAME_OP))) {
659 			walk_state->result_obj = obj_desc;
660 		}
661 	}
662 
663 	return_ACPI_STATUS(status);
664 }
665 
666 /*******************************************************************************
667  *
668  * FUNCTION:    acpi_ds_eval_bank_field_operands
669  *
670  * PARAMETERS:  walk_state      - Current walk
671  *              op              - A valid bank_field Op object
672  *
673  * RETURN:      Status
674  *
675  * DESCRIPTION: Get bank_field bank_value
676  *              Called from acpi_ds_exec_end_op during bank_field parse tree walk
677  *
678  ******************************************************************************/
679 
680 acpi_status
681 acpi_ds_eval_bank_field_operands(struct acpi_walk_state *walk_state,
682 				 union acpi_parse_object *op)
683 {
684 	acpi_status status;
685 	union acpi_operand_object *obj_desc;
686 	union acpi_operand_object *operand_desc;
687 	struct acpi_namespace_node *node;
688 	union acpi_parse_object *next_op;
689 	union acpi_parse_object *arg;
690 
691 	ACPI_FUNCTION_TRACE_PTR(ds_eval_bank_field_operands, op);
692 
693 	/*
694 	 * This is where we evaluate the bank_value field of the
695 	 * bank_field declaration
696 	 */
697 
698 	/* next_op points to the op that holds the Region */
699 
700 	next_op = op->common.value.arg;
701 
702 	/* next_op points to the op that holds the Bank Register */
703 
704 	next_op = next_op->common.next;
705 
706 	/* next_op points to the op that holds the Bank Value */
707 
708 	next_op = next_op->common.next;
709 
710 	/*
711 	 * Set proper index into operand stack for acpi_ds_obj_stack_push
712 	 * invoked inside acpi_ds_create_operand.
713 	 *
714 	 * We use walk_state->Operands[0] to store the evaluated bank_value
715 	 */
716 	walk_state->operand_index = 0;
717 
718 	status = acpi_ds_create_operand(walk_state, next_op, 0);
719 	if (ACPI_FAILURE(status)) {
720 		return_ACPI_STATUS(status);
721 	}
722 
723 	status = acpi_ex_resolve_to_value(&walk_state->operands[0], walk_state);
724 	if (ACPI_FAILURE(status)) {
725 		return_ACPI_STATUS(status);
726 	}
727 
728 	ACPI_DUMP_OPERANDS(ACPI_WALK_OPERANDS,
729 			   acpi_ps_get_opcode_name(op->common.aml_opcode), 1);
730 	/*
731 	 * Get the bank_value operand and save it
732 	 * (at Top of stack)
733 	 */
734 	operand_desc = walk_state->operands[0];
735 
736 	/* Arg points to the start Bank Field */
737 
738 	arg = acpi_ps_get_arg(op, 4);
739 	while (arg) {
740 
741 		/* Ignore OFFSET and ACCESSAS terms here */
742 
743 		if (arg->common.aml_opcode == AML_INT_NAMEDFIELD_OP) {
744 			node = arg->common.node;
745 
746 			obj_desc = acpi_ns_get_attached_object(node);
747 			if (!obj_desc) {
748 				return_ACPI_STATUS(AE_NOT_EXIST);
749 			}
750 
751 			obj_desc->bank_field.value =
752 			    (u32) operand_desc->integer.value;
753 		}
754 
755 		/* Move to next field in the list */
756 
757 		arg = arg->common.next;
758 	}
759 
760 	acpi_ut_remove_reference(operand_desc);
761 	return_ACPI_STATUS(status);
762 }
763