xref: /openbmc/linux/drivers/acpi/acpica/dsfield.c (revision 63dc02bd)
1 /******************************************************************************
2  *
3  * Module Name: dsfield - Dispatcher field routines
4  *
5  *****************************************************************************/
6 
7 /*
8  * Copyright (C) 2000 - 2012, Intel Corp.
9  * All rights reserved.
10  *
11  * Redistribution and use in source and binary forms, with or without
12  * modification, are permitted provided that the following conditions
13  * are met:
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.
25  *
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.
29  *
30  * NO WARRANTY
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.
42  */
43 
44 #include <acpi/acpi.h>
45 #include "accommon.h"
46 #include "amlcode.h"
47 #include "acdispat.h"
48 #include "acinterp.h"
49 #include "acnamesp.h"
50 #include "acparser.h"
51 
52 #define _COMPONENT          ACPI_DISPATCHER
53 ACPI_MODULE_NAME("dsfield")
54 
55 /* Local prototypes */
56 static acpi_status
57 acpi_ds_get_field_names(struct acpi_create_field_info *info,
58 			struct acpi_walk_state *walk_state,
59 			union acpi_parse_object *arg);
60 
61 /*******************************************************************************
62  *
63  * FUNCTION:    acpi_ds_create_buffer_field
64  *
65  * PARAMETERS:  Op                  - Current parse op (create_xXField)
66  *              walk_state          - Current state
67  *
68  * RETURN:      Status
69  *
70  * DESCRIPTION: Execute the create_field operators:
71  *              create_bit_field_op,
72  *              create_byte_field_op,
73  *              create_word_field_op,
74  *              create_dword_field_op,
75  *              create_qword_field_op,
76  *              create_field_op     (all of which define a field in a buffer)
77  *
78  ******************************************************************************/
79 
80 acpi_status
81 acpi_ds_create_buffer_field(union acpi_parse_object *op,
82 			    struct acpi_walk_state *walk_state)
83 {
84 	union acpi_parse_object *arg;
85 	struct acpi_namespace_node *node;
86 	acpi_status status;
87 	union acpi_operand_object *obj_desc;
88 	union acpi_operand_object *second_desc = NULL;
89 	u32 flags;
90 
91 	ACPI_FUNCTION_TRACE(ds_create_buffer_field);
92 
93 	/*
94 	 * Get the name_string argument (name of the new buffer_field)
95 	 */
96 	if (op->common.aml_opcode == AML_CREATE_FIELD_OP) {
97 
98 		/* For create_field, name is the 4th argument */
99 
100 		arg = acpi_ps_get_arg(op, 3);
101 	} else {
102 		/* For all other create_xXXField operators, name is the 3rd argument */
103 
104 		arg = acpi_ps_get_arg(op, 2);
105 	}
106 
107 	if (!arg) {
108 		return_ACPI_STATUS(AE_AML_NO_OPERAND);
109 	}
110 
111 	if (walk_state->deferred_node) {
112 		node = walk_state->deferred_node;
113 		status = AE_OK;
114 	} else {
115 		/* Execute flag should always be set when this function is entered */
116 
117 		if (!(walk_state->parse_flags & ACPI_PARSE_EXECUTE)) {
118 			return_ACPI_STATUS(AE_AML_INTERNAL);
119 		}
120 
121 		/* Creating new namespace node, should not already exist */
122 
123 		flags = ACPI_NS_NO_UPSEARCH | ACPI_NS_DONT_OPEN_SCOPE |
124 		    ACPI_NS_ERROR_IF_FOUND;
125 
126 		/*
127 		 * Mark node temporary if we are executing a normal control
128 		 * method. (Don't mark if this is a module-level code method)
129 		 */
130 		if (walk_state->method_node &&
131 		    !(walk_state->parse_flags & ACPI_PARSE_MODULE_LEVEL)) {
132 			flags |= ACPI_NS_TEMPORARY;
133 		}
134 
135 		/* Enter the name_string into the namespace */
136 
137 		status =
138 		    acpi_ns_lookup(walk_state->scope_info,
139 				   arg->common.value.string, ACPI_TYPE_ANY,
140 				   ACPI_IMODE_LOAD_PASS1, flags, walk_state,
141 				   &node);
142 		if (ACPI_FAILURE(status)) {
143 			ACPI_ERROR_NAMESPACE(arg->common.value.string, status);
144 			return_ACPI_STATUS(status);
145 		}
146 	}
147 
148 	/*
149 	 * We could put the returned object (Node) on the object stack for later,
150 	 * but for now, we will put it in the "op" object that the parser uses,
151 	 * so we can get it again at the end of this scope.
152 	 */
153 	op->common.node = node;
154 
155 	/*
156 	 * If there is no object attached to the node, this node was just created
157 	 * and we need to create the field object. Otherwise, this was a lookup
158 	 * of an existing node and we don't want to create the field object again.
159 	 */
160 	obj_desc = acpi_ns_get_attached_object(node);
161 	if (obj_desc) {
162 		return_ACPI_STATUS(AE_OK);
163 	}
164 
165 	/*
166 	 * The Field definition is not fully parsed at this time.
167 	 * (We must save the address of the AML for the buffer and index operands)
168 	 */
169 
170 	/* Create the buffer field object */
171 
172 	obj_desc = acpi_ut_create_internal_object(ACPI_TYPE_BUFFER_FIELD);
173 	if (!obj_desc) {
174 		status = AE_NO_MEMORY;
175 		goto cleanup;
176 	}
177 
178 	/*
179 	 * Remember location in AML stream of the field unit opcode and operands --
180 	 * since the buffer and index operands must be evaluated.
181 	 */
182 	second_desc = obj_desc->common.next_object;
183 	second_desc->extra.aml_start = op->named.data;
184 	second_desc->extra.aml_length = op->named.length;
185 	obj_desc->buffer_field.node = node;
186 
187 	/* Attach constructed field descriptors to parent node */
188 
189 	status = acpi_ns_attach_object(node, obj_desc, ACPI_TYPE_BUFFER_FIELD);
190 	if (ACPI_FAILURE(status)) {
191 		goto cleanup;
192 	}
193 
194       cleanup:
195 
196 	/* Remove local reference to the object */
197 
198 	acpi_ut_remove_reference(obj_desc);
199 	return_ACPI_STATUS(status);
200 }
201 
202 /*******************************************************************************
203  *
204  * FUNCTION:    acpi_ds_get_field_names
205  *
206  * PARAMETERS:  Info            - create_field info structure
207  *  `           walk_state      - Current method state
208  *              Arg             - First parser arg for the field name list
209  *
210  * RETURN:      Status
211  *
212  * DESCRIPTION: Process all named fields in a field declaration.  Names are
213  *              entered into the namespace.
214  *
215  ******************************************************************************/
216 
217 static acpi_status
218 acpi_ds_get_field_names(struct acpi_create_field_info *info,
219 			struct acpi_walk_state *walk_state,
220 			union acpi_parse_object *arg)
221 {
222 	acpi_status status;
223 	u64 position;
224 	union acpi_parse_object *child;
225 
226 	ACPI_FUNCTION_TRACE_PTR(ds_get_field_names, info);
227 
228 	/* First field starts at bit zero */
229 
230 	info->field_bit_position = 0;
231 
232 	/* Process all elements in the field list (of parse nodes) */
233 
234 	while (arg) {
235 		/*
236 		 * Four types of field elements are handled:
237 		 * 1) Name - Enters a new named field into the namespace
238 		 * 2) Offset - specifies a bit offset
239 		 * 3) access_as - changes the access mode/attributes
240 		 * 4) Connection - Associate a resource template with the field
241 		 */
242 		switch (arg->common.aml_opcode) {
243 		case AML_INT_RESERVEDFIELD_OP:
244 
245 			position = (u64) info->field_bit_position
246 			    + (u64) arg->common.value.size;
247 
248 			if (position > ACPI_UINT32_MAX) {
249 				ACPI_ERROR((AE_INFO,
250 					    "Bit offset within field too large (> 0xFFFFFFFF)"));
251 				return_ACPI_STATUS(AE_SUPPORT);
252 			}
253 
254 			info->field_bit_position = (u32) position;
255 			break;
256 
257 		case AML_INT_ACCESSFIELD_OP:
258 		case AML_INT_EXTACCESSFIELD_OP:
259 			/*
260 			 * Get new access_type, access_attribute, and access_length fields
261 			 * -- to be used for all field units that follow, until the
262 			 * end-of-field or another access_as keyword is encountered.
263 			 * NOTE. These three bytes are encoded in the integer value
264 			 * of the parseop for convenience.
265 			 *
266 			 * In field_flags, preserve the flag bits other than the
267 			 * ACCESS_TYPE bits.
268 			 */
269 
270 			/* access_type (byte_acc, word_acc, etc.) */
271 
272 			info->field_flags = (u8)
273 			    ((info->
274 			      field_flags & ~(AML_FIELD_ACCESS_TYPE_MASK)) |
275 			     ((u8)((u32)(arg->common.value.integer & 0x07))));
276 
277 			/* access_attribute (attrib_quick, attrib_byte, etc.) */
278 
279 			info->attribute =
280 			    (u8)((arg->common.value.integer >> 8) & 0xFF);
281 
282 			/* access_length (for serial/buffer protocols) */
283 
284 			info->access_length =
285 			    (u8)((arg->common.value.integer >> 16) & 0xFF);
286 			break;
287 
288 		case AML_INT_CONNECTION_OP:
289 			/*
290 			 * Clear any previous connection. New connection is used for all
291 			 * fields that follow, similar to access_as
292 			 */
293 			info->resource_buffer = NULL;
294 			info->connection_node = NULL;
295 
296 			/*
297 			 * A Connection() is either an actual resource descriptor (buffer)
298 			 * or a named reference to a resource template
299 			 */
300 			child = arg->common.value.arg;
301 			if (child->common.aml_opcode == AML_INT_BYTELIST_OP) {
302 				info->resource_buffer = child->named.data;
303 				info->resource_length =
304 				    (u16)child->named.value.integer;
305 			} else {
306 				/* Lookup the Connection() namepath, it should already exist */
307 
308 				status = acpi_ns_lookup(walk_state->scope_info,
309 							child->common.value.
310 							name, ACPI_TYPE_ANY,
311 							ACPI_IMODE_EXECUTE,
312 							ACPI_NS_DONT_OPEN_SCOPE,
313 							walk_state,
314 							&info->connection_node);
315 				if (ACPI_FAILURE(status)) {
316 					ACPI_ERROR_NAMESPACE(child->common.
317 							     value.name,
318 							     status);
319 					return_ACPI_STATUS(status);
320 				}
321 			}
322 			break;
323 
324 		case AML_INT_NAMEDFIELD_OP:
325 
326 			/* Lookup the name, it should already exist */
327 
328 			status = acpi_ns_lookup(walk_state->scope_info,
329 						(char *)&arg->named.name,
330 						info->field_type,
331 						ACPI_IMODE_EXECUTE,
332 						ACPI_NS_DONT_OPEN_SCOPE,
333 						walk_state, &info->field_node);
334 			if (ACPI_FAILURE(status)) {
335 				ACPI_ERROR_NAMESPACE((char *)&arg->named.name,
336 						     status);
337 				return_ACPI_STATUS(status);
338 			} else {
339 				arg->common.node = info->field_node;
340 				info->field_bit_length = arg->common.value.size;
341 
342 				/*
343 				 * If there is no object attached to the node, this node was
344 				 * just created and we need to create the field object.
345 				 * Otherwise, this was a lookup of an existing node and we
346 				 * don't want to create the field object again.
347 				 */
348 				if (!acpi_ns_get_attached_object
349 				    (info->field_node)) {
350 					status = acpi_ex_prep_field_value(info);
351 					if (ACPI_FAILURE(status)) {
352 						return_ACPI_STATUS(status);
353 					}
354 				}
355 			}
356 
357 			/* Keep track of bit position for the next field */
358 
359 			position = (u64) info->field_bit_position
360 			    + (u64) arg->common.value.size;
361 
362 			if (position > ACPI_UINT32_MAX) {
363 				ACPI_ERROR((AE_INFO,
364 					    "Field [%4.4s] bit offset too large (> 0xFFFFFFFF)",
365 					    ACPI_CAST_PTR(char,
366 							  &info->field_node->
367 							  name)));
368 				return_ACPI_STATUS(AE_SUPPORT);
369 			}
370 
371 			info->field_bit_position += info->field_bit_length;
372 			break;
373 
374 		default:
375 
376 			ACPI_ERROR((AE_INFO,
377 				    "Invalid opcode in field list: 0x%X",
378 				    arg->common.aml_opcode));
379 			return_ACPI_STATUS(AE_AML_BAD_OPCODE);
380 		}
381 
382 		arg = arg->common.next;
383 	}
384 
385 	return_ACPI_STATUS(AE_OK);
386 }
387 
388 /*******************************************************************************
389  *
390  * FUNCTION:    acpi_ds_create_field
391  *
392  * PARAMETERS:  Op              - Op containing the Field definition and args
393  *              region_node     - Object for the containing Operation Region
394  *  `           walk_state      - Current method state
395  *
396  * RETURN:      Status
397  *
398  * DESCRIPTION: Create a new field in the specified operation region
399  *
400  ******************************************************************************/
401 
402 acpi_status
403 acpi_ds_create_field(union acpi_parse_object *op,
404 		     struct acpi_namespace_node *region_node,
405 		     struct acpi_walk_state *walk_state)
406 {
407 	acpi_status status;
408 	union acpi_parse_object *arg;
409 	struct acpi_create_field_info info;
410 
411 	ACPI_FUNCTION_TRACE_PTR(ds_create_field, op);
412 
413 	/* First arg is the name of the parent op_region (must already exist) */
414 
415 	arg = op->common.value.arg;
416 	if (!region_node) {
417 		status =
418 		    acpi_ns_lookup(walk_state->scope_info,
419 				   arg->common.value.name, ACPI_TYPE_REGION,
420 				   ACPI_IMODE_EXECUTE, ACPI_NS_SEARCH_PARENT,
421 				   walk_state, &region_node);
422 		if (ACPI_FAILURE(status)) {
423 			ACPI_ERROR_NAMESPACE(arg->common.value.name, status);
424 			return_ACPI_STATUS(status);
425 		}
426 	}
427 
428 	ACPI_MEMSET(&info, 0, sizeof(struct acpi_create_field_info));
429 
430 	/* Second arg is the field flags */
431 
432 	arg = arg->common.next;
433 	info.field_flags = (u8) arg->common.value.integer;
434 	info.attribute = 0;
435 
436 	/* Each remaining arg is a Named Field */
437 
438 	info.field_type = ACPI_TYPE_LOCAL_REGION_FIELD;
439 	info.region_node = region_node;
440 
441 	status = acpi_ds_get_field_names(&info, walk_state, arg->common.next);
442 	return_ACPI_STATUS(status);
443 }
444 
445 /*******************************************************************************
446  *
447  * FUNCTION:    acpi_ds_init_field_objects
448  *
449  * PARAMETERS:  Op              - Op containing the Field definition and args
450  *  `           walk_state      - Current method state
451  *
452  * RETURN:      Status
453  *
454  * DESCRIPTION: For each "Field Unit" name in the argument list that is
455  *              part of the field declaration, enter the name into the
456  *              namespace.
457  *
458  ******************************************************************************/
459 
460 acpi_status
461 acpi_ds_init_field_objects(union acpi_parse_object *op,
462 			   struct acpi_walk_state *walk_state)
463 {
464 	acpi_status status;
465 	union acpi_parse_object *arg = NULL;
466 	struct acpi_namespace_node *node;
467 	u8 type = 0;
468 	u32 flags;
469 
470 	ACPI_FUNCTION_TRACE_PTR(ds_init_field_objects, op);
471 
472 	/* Execute flag should always be set when this function is entered */
473 
474 	if (!(walk_state->parse_flags & ACPI_PARSE_EXECUTE)) {
475 		if (walk_state->parse_flags & ACPI_PARSE_DEFERRED_OP) {
476 
477 			/* bank_field Op is deferred, just return OK */
478 
479 			return_ACPI_STATUS(AE_OK);
480 		}
481 
482 		return_ACPI_STATUS(AE_AML_INTERNAL);
483 	}
484 
485 	/*
486 	 * Get the field_list argument for this opcode. This is the start of the
487 	 * list of field elements.
488 	 */
489 	switch (walk_state->opcode) {
490 	case AML_FIELD_OP:
491 		arg = acpi_ps_get_arg(op, 2);
492 		type = ACPI_TYPE_LOCAL_REGION_FIELD;
493 		break;
494 
495 	case AML_BANK_FIELD_OP:
496 		arg = acpi_ps_get_arg(op, 4);
497 		type = ACPI_TYPE_LOCAL_BANK_FIELD;
498 		break;
499 
500 	case AML_INDEX_FIELD_OP:
501 		arg = acpi_ps_get_arg(op, 3);
502 		type = ACPI_TYPE_LOCAL_INDEX_FIELD;
503 		break;
504 
505 	default:
506 		return_ACPI_STATUS(AE_BAD_PARAMETER);
507 	}
508 
509 	/* Creating new namespace node(s), should not already exist */
510 
511 	flags = ACPI_NS_NO_UPSEARCH | ACPI_NS_DONT_OPEN_SCOPE |
512 	    ACPI_NS_ERROR_IF_FOUND;
513 
514 	/*
515 	 * Mark node(s) temporary if we are executing a normal control
516 	 * method. (Don't mark if this is a module-level code method)
517 	 */
518 	if (walk_state->method_node &&
519 	    !(walk_state->parse_flags & ACPI_PARSE_MODULE_LEVEL)) {
520 		flags |= ACPI_NS_TEMPORARY;
521 	}
522 
523 	/*
524 	 * Walk the list of entries in the field_list
525 	 * Note: field_list can be of zero length. In this case, Arg will be NULL.
526 	 */
527 	while (arg) {
528 		/*
529 		 * Ignore OFFSET/ACCESSAS/CONNECTION terms here; we are only interested
530 		 * in the field names in order to enter them into the namespace.
531 		 */
532 		if (arg->common.aml_opcode == AML_INT_NAMEDFIELD_OP) {
533 			status = acpi_ns_lookup(walk_state->scope_info,
534 						(char *)&arg->named.name, type,
535 						ACPI_IMODE_LOAD_PASS1, flags,
536 						walk_state, &node);
537 			if (ACPI_FAILURE(status)) {
538 				ACPI_ERROR_NAMESPACE((char *)&arg->named.name,
539 						     status);
540 				if (status != AE_ALREADY_EXISTS) {
541 					return_ACPI_STATUS(status);
542 				}
543 
544 				/* Name already exists, just ignore this error */
545 
546 				status = AE_OK;
547 			}
548 
549 			arg->common.node = node;
550 		}
551 
552 		/* Get the next field element in the list */
553 
554 		arg = arg->common.next;
555 	}
556 
557 	return_ACPI_STATUS(AE_OK);
558 }
559 
560 /*******************************************************************************
561  *
562  * FUNCTION:    acpi_ds_create_bank_field
563  *
564  * PARAMETERS:  Op              - Op containing the Field definition and args
565  *              region_node     - Object for the containing Operation Region
566  *              walk_state      - Current method state
567  *
568  * RETURN:      Status
569  *
570  * DESCRIPTION: Create a new bank field in the specified operation region
571  *
572  ******************************************************************************/
573 
574 acpi_status
575 acpi_ds_create_bank_field(union acpi_parse_object *op,
576 			  struct acpi_namespace_node *region_node,
577 			  struct acpi_walk_state *walk_state)
578 {
579 	acpi_status status;
580 	union acpi_parse_object *arg;
581 	struct acpi_create_field_info info;
582 
583 	ACPI_FUNCTION_TRACE_PTR(ds_create_bank_field, op);
584 
585 	/* First arg is the name of the parent op_region (must already exist) */
586 
587 	arg = op->common.value.arg;
588 	if (!region_node) {
589 		status =
590 		    acpi_ns_lookup(walk_state->scope_info,
591 				   arg->common.value.name, ACPI_TYPE_REGION,
592 				   ACPI_IMODE_EXECUTE, ACPI_NS_SEARCH_PARENT,
593 				   walk_state, &region_node);
594 		if (ACPI_FAILURE(status)) {
595 			ACPI_ERROR_NAMESPACE(arg->common.value.name, status);
596 			return_ACPI_STATUS(status);
597 		}
598 	}
599 
600 	/* Second arg is the Bank Register (Field) (must already exist) */
601 
602 	arg = arg->common.next;
603 	status =
604 	    acpi_ns_lookup(walk_state->scope_info, arg->common.value.string,
605 			   ACPI_TYPE_ANY, ACPI_IMODE_EXECUTE,
606 			   ACPI_NS_SEARCH_PARENT, walk_state,
607 			   &info.register_node);
608 	if (ACPI_FAILURE(status)) {
609 		ACPI_ERROR_NAMESPACE(arg->common.value.string, status);
610 		return_ACPI_STATUS(status);
611 	}
612 
613 	/*
614 	 * Third arg is the bank_value
615 	 * This arg is a term_arg, not a constant
616 	 * It will be evaluated later, by acpi_ds_eval_bank_field_operands
617 	 */
618 	arg = arg->common.next;
619 
620 	/* Fourth arg is the field flags */
621 
622 	arg = arg->common.next;
623 	info.field_flags = (u8) arg->common.value.integer;
624 
625 	/* Each remaining arg is a Named Field */
626 
627 	info.field_type = ACPI_TYPE_LOCAL_BANK_FIELD;
628 	info.region_node = region_node;
629 
630 	/*
631 	 * Use Info.data_register_node to store bank_field Op
632 	 * It's safe because data_register_node will never be used when create bank field
633 	 * We store aml_start and aml_length in the bank_field Op for late evaluation
634 	 * Used in acpi_ex_prep_field_value(Info)
635 	 *
636 	 * TBD: Or, should we add a field in struct acpi_create_field_info, like "void *ParentOp"?
637 	 */
638 	info.data_register_node = (struct acpi_namespace_node *)op;
639 
640 	status = acpi_ds_get_field_names(&info, walk_state, arg->common.next);
641 	return_ACPI_STATUS(status);
642 }
643 
644 /*******************************************************************************
645  *
646  * FUNCTION:    acpi_ds_create_index_field
647  *
648  * PARAMETERS:  Op              - Op containing the Field definition and args
649  *              region_node     - Object for the containing Operation Region
650  *  `           walk_state      - Current method state
651  *
652  * RETURN:      Status
653  *
654  * DESCRIPTION: Create a new index field in the specified operation region
655  *
656  ******************************************************************************/
657 
658 acpi_status
659 acpi_ds_create_index_field(union acpi_parse_object *op,
660 			   struct acpi_namespace_node *region_node,
661 			   struct acpi_walk_state *walk_state)
662 {
663 	acpi_status status;
664 	union acpi_parse_object *arg;
665 	struct acpi_create_field_info info;
666 
667 	ACPI_FUNCTION_TRACE_PTR(ds_create_index_field, op);
668 
669 	/* First arg is the name of the Index register (must already exist) */
670 
671 	arg = op->common.value.arg;
672 	status =
673 	    acpi_ns_lookup(walk_state->scope_info, arg->common.value.string,
674 			   ACPI_TYPE_ANY, ACPI_IMODE_EXECUTE,
675 			   ACPI_NS_SEARCH_PARENT, walk_state,
676 			   &info.register_node);
677 	if (ACPI_FAILURE(status)) {
678 		ACPI_ERROR_NAMESPACE(arg->common.value.string, status);
679 		return_ACPI_STATUS(status);
680 	}
681 
682 	/* Second arg is the data register (must already exist) */
683 
684 	arg = arg->common.next;
685 	status =
686 	    acpi_ns_lookup(walk_state->scope_info, arg->common.value.string,
687 			   ACPI_TYPE_ANY, ACPI_IMODE_EXECUTE,
688 			   ACPI_NS_SEARCH_PARENT, walk_state,
689 			   &info.data_register_node);
690 	if (ACPI_FAILURE(status)) {
691 		ACPI_ERROR_NAMESPACE(arg->common.value.string, status);
692 		return_ACPI_STATUS(status);
693 	}
694 
695 	/* Next arg is the field flags */
696 
697 	arg = arg->common.next;
698 	info.field_flags = (u8) arg->common.value.integer;
699 
700 	/* Each remaining arg is a Named Field */
701 
702 	info.field_type = ACPI_TYPE_LOCAL_INDEX_FIELD;
703 	info.region_node = region_node;
704 
705 	status = acpi_ds_get_field_names(&info, walk_state, arg->common.next);
706 	return_ACPI_STATUS(status);
707 }
708