xref: /openbmc/linux/drivers/acpi/acpica/rscalc.c (revision 97028ce6fca0fec53ee71e2fd5acfb2dc8430f1f)
1 /*******************************************************************************
2  *
3  * Module Name: rscalc - Calculate stream and list lengths
4  *
5  ******************************************************************************/
6 
7 /*
8  * Copyright (C) 2000 - 2017, 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 "acresrc.h"
47 #include "acnamesp.h"
48 
49 #define _COMPONENT          ACPI_RESOURCES
50 ACPI_MODULE_NAME("rscalc")
51 
52 /* Local prototypes */
53 static u8 acpi_rs_count_set_bits(u16 bit_field);
54 
55 static acpi_rs_length
56 acpi_rs_struct_option_length(struct acpi_resource_source *resource_source);
57 
58 static u32
59 acpi_rs_stream_option_length(u32 resource_length, u32 minimum_total_length);
60 
61 /*******************************************************************************
62  *
63  * FUNCTION:    acpi_rs_count_set_bits
64  *
65  * PARAMETERS:  bit_field       - Field in which to count bits
66  *
67  * RETURN:      Number of bits set within the field
68  *
69  * DESCRIPTION: Count the number of bits set in a resource field. Used for
70  *              (Short descriptor) interrupt and DMA lists.
71  *
72  ******************************************************************************/
73 
74 static u8 acpi_rs_count_set_bits(u16 bit_field)
75 {
76 	u8 bits_set;
77 
78 	ACPI_FUNCTION_ENTRY();
79 
80 	for (bits_set = 0; bit_field; bits_set++) {
81 
82 		/* Zero the least significant bit that is set */
83 
84 		bit_field &= (u16) (bit_field - 1);
85 	}
86 
87 	return (bits_set);
88 }
89 
90 /*******************************************************************************
91  *
92  * FUNCTION:    acpi_rs_struct_option_length
93  *
94  * PARAMETERS:  resource_source     - Pointer to optional descriptor field
95  *
96  * RETURN:      Status
97  *
98  * DESCRIPTION: Common code to handle optional resource_source_index and
99  *              resource_source fields in some Large descriptors. Used during
100  *              list-to-stream conversion
101  *
102  ******************************************************************************/
103 
104 static acpi_rs_length
105 acpi_rs_struct_option_length(struct acpi_resource_source *resource_source)
106 {
107 	ACPI_FUNCTION_ENTRY();
108 
109 	/*
110 	 * If the resource_source string is valid, return the size of the string
111 	 * (string_length includes the NULL terminator) plus the size of the
112 	 * resource_source_index (1).
113 	 */
114 	if (resource_source->string_ptr) {
115 		return ((acpi_rs_length)(resource_source->string_length + 1));
116 	}
117 
118 	return (0);
119 }
120 
121 /*******************************************************************************
122  *
123  * FUNCTION:    acpi_rs_stream_option_length
124  *
125  * PARAMETERS:  resource_length     - Length from the resource header
126  *              minimum_total_length - Minimum length of this resource, before
127  *                                    any optional fields. Includes header size
128  *
129  * RETURN:      Length of optional string (0 if no string present)
130  *
131  * DESCRIPTION: Common code to handle optional resource_source_index and
132  *              resource_source fields in some Large descriptors. Used during
133  *              stream-to-list conversion
134  *
135  ******************************************************************************/
136 
137 static u32
138 acpi_rs_stream_option_length(u32 resource_length,
139 			     u32 minimum_aml_resource_length)
140 {
141 	u32 string_length = 0;
142 
143 	ACPI_FUNCTION_ENTRY();
144 
145 	/*
146 	 * The resource_source_index and resource_source are optional elements of
147 	 * some Large-type resource descriptors.
148 	 */
149 
150 	/*
151 	 * If the length of the actual resource descriptor is greater than the
152 	 * ACPI spec-defined minimum length, it means that a resource_source_index
153 	 * exists and is followed by a (required) null terminated string. The
154 	 * string length (including the null terminator) is the resource length
155 	 * minus the minimum length, minus one byte for the resource_source_index
156 	 * itself.
157 	 */
158 	if (resource_length > minimum_aml_resource_length) {
159 
160 		/* Compute the length of the optional string */
161 
162 		string_length =
163 		    resource_length - minimum_aml_resource_length - 1;
164 	}
165 
166 	/*
167 	 * Round the length up to a multiple of the native word in order to
168 	 * guarantee that the entire resource descriptor is native word aligned
169 	 */
170 	return ((u32) ACPI_ROUND_UP_TO_NATIVE_WORD(string_length));
171 }
172 
173 /*******************************************************************************
174  *
175  * FUNCTION:    acpi_rs_get_aml_length
176  *
177  * PARAMETERS:  resource            - Pointer to the resource linked list
178  *              resource_list_size  - Size of the resource linked list
179  *              size_needed         - Where the required size is returned
180  *
181  * RETURN:      Status
182  *
183  * DESCRIPTION: Takes a linked list of internal resource descriptors and
184  *              calculates the size buffer needed to hold the corresponding
185  *              external resource byte stream.
186  *
187  ******************************************************************************/
188 
189 acpi_status
190 acpi_rs_get_aml_length(struct acpi_resource *resource,
191 		       acpi_size resource_list_size, acpi_size *size_needed)
192 {
193 	acpi_size aml_size_needed = 0;
194 	struct acpi_resource *resource_end;
195 	acpi_rs_length total_size;
196 
197 	ACPI_FUNCTION_TRACE(rs_get_aml_length);
198 
199 	/* Traverse entire list of internal resource descriptors */
200 
201 	resource_end =
202 	    ACPI_ADD_PTR(struct acpi_resource, resource, resource_list_size);
203 	while (resource < resource_end) {
204 
205 		/* Validate the descriptor type */
206 
207 		if (resource->type > ACPI_RESOURCE_TYPE_MAX) {
208 			return_ACPI_STATUS(AE_AML_INVALID_RESOURCE_TYPE);
209 		}
210 
211 		/* Sanity check the length. It must not be zero, or we loop forever */
212 
213 		if (!resource->length) {
214 			return_ACPI_STATUS(AE_AML_BAD_RESOURCE_LENGTH);
215 		}
216 
217 		/* Get the base size of the (external stream) resource descriptor */
218 
219 		total_size = acpi_gbl_aml_resource_sizes[resource->type];
220 
221 		/*
222 		 * Augment the base size for descriptors with optional and/or
223 		 * variable-length fields
224 		 */
225 		switch (resource->type) {
226 		case ACPI_RESOURCE_TYPE_IRQ:
227 
228 			/* Length can be 3 or 2 */
229 
230 			if (resource->data.irq.descriptor_length == 2) {
231 				total_size--;
232 			}
233 			break;
234 
235 		case ACPI_RESOURCE_TYPE_START_DEPENDENT:
236 
237 			/* Length can be 1 or 0 */
238 
239 			if (resource->data.irq.descriptor_length == 0) {
240 				total_size--;
241 			}
242 			break;
243 
244 		case ACPI_RESOURCE_TYPE_VENDOR:
245 			/*
246 			 * Vendor Defined Resource:
247 			 * For a Vendor Specific resource, if the Length is between 1 and 7
248 			 * it will be created as a Small Resource data type, otherwise it
249 			 * is a Large Resource data type.
250 			 */
251 			if (resource->data.vendor.byte_length > 7) {
252 
253 				/* Base size of a Large resource descriptor */
254 
255 				total_size =
256 				    sizeof(struct aml_resource_large_header);
257 			}
258 
259 			/* Add the size of the vendor-specific data */
260 
261 			total_size = (acpi_rs_length)
262 			    (total_size + resource->data.vendor.byte_length);
263 			break;
264 
265 		case ACPI_RESOURCE_TYPE_END_TAG:
266 			/*
267 			 * End Tag:
268 			 * We are done -- return the accumulated total size.
269 			 */
270 			*size_needed = aml_size_needed + total_size;
271 
272 			/* Normal exit */
273 
274 			return_ACPI_STATUS(AE_OK);
275 
276 		case ACPI_RESOURCE_TYPE_ADDRESS16:
277 			/*
278 			 * 16-Bit Address Resource:
279 			 * Add the size of the optional resource_source info
280 			 */
281 			total_size = (acpi_rs_length)(total_size +
282 						      acpi_rs_struct_option_length
283 						      (&resource->data.
284 						       address16.
285 						       resource_source));
286 			break;
287 
288 		case ACPI_RESOURCE_TYPE_ADDRESS32:
289 			/*
290 			 * 32-Bit Address Resource:
291 			 * Add the size of the optional resource_source info
292 			 */
293 			total_size = (acpi_rs_length)(total_size +
294 						      acpi_rs_struct_option_length
295 						      (&resource->data.
296 						       address32.
297 						       resource_source));
298 			break;
299 
300 		case ACPI_RESOURCE_TYPE_ADDRESS64:
301 			/*
302 			 * 64-Bit Address Resource:
303 			 * Add the size of the optional resource_source info
304 			 */
305 			total_size = (acpi_rs_length)(total_size +
306 						      acpi_rs_struct_option_length
307 						      (&resource->data.
308 						       address64.
309 						       resource_source));
310 			break;
311 
312 		case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
313 			/*
314 			 * Extended IRQ Resource:
315 			 * Add the size of each additional optional interrupt beyond the
316 			 * required 1 (4 bytes for each u32 interrupt number)
317 			 */
318 			total_size = (acpi_rs_length)(total_size +
319 						      ((resource->data.
320 							extended_irq.
321 							interrupt_count -
322 							1) * 4) +
323 						      /* Add the size of the optional resource_source info */
324 						      acpi_rs_struct_option_length
325 						      (&resource->data.
326 						       extended_irq.
327 						       resource_source));
328 			break;
329 
330 		case ACPI_RESOURCE_TYPE_GPIO:
331 
332 			total_size = (acpi_rs_length)(total_size +
333 						      (resource->data.gpio.
334 						       pin_table_length * 2) +
335 						      resource->data.gpio.
336 						      resource_source.
337 						      string_length +
338 						      resource->data.gpio.
339 						      vendor_length);
340 
341 			break;
342 
343 		case ACPI_RESOURCE_TYPE_PIN_FUNCTION:
344 
345 			total_size = (acpi_rs_length)(total_size +
346 						      (resource->data.
347 						       pin_function.
348 						       pin_table_length * 2) +
349 						      resource->data.
350 						      pin_function.
351 						      resource_source.
352 						      string_length +
353 						      resource->data.
354 						      pin_function.
355 						      vendor_length);
356 
357 			break;
358 
359 		case ACPI_RESOURCE_TYPE_SERIAL_BUS:
360 
361 			total_size =
362 			    acpi_gbl_aml_resource_serial_bus_sizes[resource->
363 								   data.
364 								   common_serial_bus.
365 								   type];
366 
367 			total_size = (acpi_rs_length)(total_size +
368 						      resource->data.
369 						      i2c_serial_bus.
370 						      resource_source.
371 						      string_length +
372 						      resource->data.
373 						      i2c_serial_bus.
374 						      vendor_length);
375 
376 			break;
377 
378 		case ACPI_RESOURCE_TYPE_PIN_CONFIG:
379 
380 			total_size = (acpi_rs_length)(total_size +
381 						      (resource->data.
382 						       pin_config.
383 						       pin_table_length * 2) +
384 						      resource->data.pin_config.
385 						      resource_source.
386 						      string_length +
387 						      resource->data.pin_config.
388 						      vendor_length);
389 
390 			break;
391 
392 		default:
393 
394 			break;
395 		}
396 
397 		/* Update the total */
398 
399 		aml_size_needed += total_size;
400 
401 		/* Point to the next object */
402 
403 		resource =
404 		    ACPI_ADD_PTR(struct acpi_resource, resource,
405 				 resource->length);
406 	}
407 
408 	/* Did not find an end_tag resource descriptor */
409 
410 	return_ACPI_STATUS(AE_AML_NO_RESOURCE_END_TAG);
411 }
412 
413 /*******************************************************************************
414  *
415  * FUNCTION:    acpi_rs_get_list_length
416  *
417  * PARAMETERS:  aml_buffer          - Pointer to the resource byte stream
418  *              aml_buffer_length   - Size of aml_buffer
419  *              size_needed         - Where the size needed is returned
420  *
421  * RETURN:      Status
422  *
423  * DESCRIPTION: Takes an external resource byte stream and calculates the size
424  *              buffer needed to hold the corresponding internal resource
425  *              descriptor linked list.
426  *
427  ******************************************************************************/
428 
429 acpi_status
430 acpi_rs_get_list_length(u8 *aml_buffer,
431 			u32 aml_buffer_length, acpi_size *size_needed)
432 {
433 	acpi_status status;
434 	u8 *end_aml;
435 	u8 *buffer;
436 	u32 buffer_size;
437 	u16 temp16;
438 	u16 resource_length;
439 	u32 extra_struct_bytes;
440 	u8 resource_index;
441 	u8 minimum_aml_resource_length;
442 	union aml_resource *aml_resource;
443 
444 	ACPI_FUNCTION_TRACE(rs_get_list_length);
445 
446 	*size_needed = ACPI_RS_SIZE_MIN;	/* Minimum size is one end_tag */
447 	end_aml = aml_buffer + aml_buffer_length;
448 
449 	/* Walk the list of AML resource descriptors */
450 
451 	while (aml_buffer < end_aml) {
452 
453 		/* Validate the Resource Type and Resource Length */
454 
455 		status =
456 		    acpi_ut_validate_resource(NULL, aml_buffer,
457 					      &resource_index);
458 		if (ACPI_FAILURE(status)) {
459 			/*
460 			 * Exit on failure. Cannot continue because the descriptor length
461 			 * may be bogus also.
462 			 */
463 			return_ACPI_STATUS(status);
464 		}
465 
466 		aml_resource = (void *)aml_buffer;
467 
468 		/* Get the resource length and base (minimum) AML size */
469 
470 		resource_length = acpi_ut_get_resource_length(aml_buffer);
471 		minimum_aml_resource_length =
472 		    acpi_gbl_resource_aml_sizes[resource_index];
473 
474 		/*
475 		 * Augment the size for descriptors with optional
476 		 * and/or variable length fields
477 		 */
478 		extra_struct_bytes = 0;
479 		buffer =
480 		    aml_buffer + acpi_ut_get_resource_header_length(aml_buffer);
481 
482 		switch (acpi_ut_get_resource_type(aml_buffer)) {
483 		case ACPI_RESOURCE_NAME_IRQ:
484 			/*
485 			 * IRQ Resource:
486 			 * Get the number of bits set in the 16-bit IRQ mask
487 			 */
488 			ACPI_MOVE_16_TO_16(&temp16, buffer);
489 			extra_struct_bytes = acpi_rs_count_set_bits(temp16);
490 			break;
491 
492 		case ACPI_RESOURCE_NAME_DMA:
493 			/*
494 			 * DMA Resource:
495 			 * Get the number of bits set in the 8-bit DMA mask
496 			 */
497 			extra_struct_bytes = acpi_rs_count_set_bits(*buffer);
498 			break;
499 
500 		case ACPI_RESOURCE_NAME_VENDOR_SMALL:
501 		case ACPI_RESOURCE_NAME_VENDOR_LARGE:
502 			/*
503 			 * Vendor Resource:
504 			 * Get the number of vendor data bytes
505 			 */
506 			extra_struct_bytes = resource_length;
507 
508 			/*
509 			 * There is already one byte included in the minimum
510 			 * descriptor size. If there are extra struct bytes,
511 			 * subtract one from the count.
512 			 */
513 			if (extra_struct_bytes) {
514 				extra_struct_bytes--;
515 			}
516 			break;
517 
518 		case ACPI_RESOURCE_NAME_END_TAG:
519 			/*
520 			 * End Tag: This is the normal exit
521 			 */
522 			return_ACPI_STATUS(AE_OK);
523 
524 		case ACPI_RESOURCE_NAME_ADDRESS32:
525 		case ACPI_RESOURCE_NAME_ADDRESS16:
526 		case ACPI_RESOURCE_NAME_ADDRESS64:
527 			/*
528 			 * Address Resource:
529 			 * Add the size of the optional resource_source
530 			 */
531 			extra_struct_bytes =
532 			    acpi_rs_stream_option_length(resource_length,
533 							 minimum_aml_resource_length);
534 			break;
535 
536 		case ACPI_RESOURCE_NAME_EXTENDED_IRQ:
537 			/*
538 			 * Extended IRQ Resource:
539 			 * Using the interrupt_table_length, add 4 bytes for each additional
540 			 * interrupt. Note: at least one interrupt is required and is
541 			 * included in the minimum descriptor size (reason for the -1)
542 			 */
543 			extra_struct_bytes = (buffer[1] - 1) * sizeof(u32);
544 
545 			/* Add the size of the optional resource_source */
546 
547 			extra_struct_bytes +=
548 			    acpi_rs_stream_option_length(resource_length -
549 							 extra_struct_bytes,
550 							 minimum_aml_resource_length);
551 			break;
552 
553 		case ACPI_RESOURCE_NAME_GPIO:
554 
555 			/* Vendor data is optional */
556 
557 			if (aml_resource->gpio.vendor_length) {
558 				extra_struct_bytes +=
559 				    aml_resource->gpio.vendor_offset -
560 				    aml_resource->gpio.pin_table_offset +
561 				    aml_resource->gpio.vendor_length;
562 			} else {
563 				extra_struct_bytes +=
564 				    aml_resource->large_header.resource_length +
565 				    sizeof(struct aml_resource_large_header) -
566 				    aml_resource->gpio.pin_table_offset;
567 			}
568 			break;
569 
570 		case ACPI_RESOURCE_NAME_PIN_FUNCTION:
571 
572 			/* Vendor data is optional */
573 
574 			if (aml_resource->pin_function.vendor_length) {
575 				extra_struct_bytes +=
576 				    aml_resource->pin_function.vendor_offset -
577 				    aml_resource->pin_function.
578 				    pin_table_offset +
579 				    aml_resource->pin_function.vendor_length;
580 			} else {
581 				extra_struct_bytes +=
582 				    aml_resource->large_header.resource_length +
583 				    sizeof(struct aml_resource_large_header) -
584 				    aml_resource->pin_function.pin_table_offset;
585 			}
586 			break;
587 
588 		case ACPI_RESOURCE_NAME_SERIAL_BUS:
589 
590 			minimum_aml_resource_length =
591 			    acpi_gbl_resource_aml_serial_bus_sizes
592 			    [aml_resource->common_serial_bus.type];
593 			extra_struct_bytes +=
594 			    aml_resource->common_serial_bus.resource_length -
595 			    minimum_aml_resource_length;
596 			break;
597 
598 		case ACPI_RESOURCE_NAME_PIN_CONFIG:
599 
600 			/* Vendor data is optional */
601 
602 			if (aml_resource->pin_config.vendor_length) {
603 				extra_struct_bytes +=
604 				    aml_resource->pin_config.vendor_offset -
605 				    aml_resource->pin_config.pin_table_offset +
606 				    aml_resource->pin_config.vendor_length;
607 			} else {
608 				extra_struct_bytes +=
609 				    aml_resource->large_header.resource_length +
610 				    sizeof(struct aml_resource_large_header) -
611 				    aml_resource->pin_config.pin_table_offset;
612 			}
613 			break;
614 
615 		default:
616 
617 			break;
618 		}
619 
620 		/*
621 		 * Update the required buffer size for the internal descriptor structs
622 		 *
623 		 * Important: Round the size up for the appropriate alignment. This
624 		 * is a requirement on IA64.
625 		 */
626 		if (acpi_ut_get_resource_type(aml_buffer) ==
627 		    ACPI_RESOURCE_NAME_SERIAL_BUS) {
628 			buffer_size =
629 			    acpi_gbl_resource_struct_serial_bus_sizes
630 			    [aml_resource->common_serial_bus.type] +
631 			    extra_struct_bytes;
632 		} else {
633 			buffer_size =
634 			    acpi_gbl_resource_struct_sizes[resource_index] +
635 			    extra_struct_bytes;
636 		}
637 
638 		buffer_size = (u32)ACPI_ROUND_UP_TO_NATIVE_WORD(buffer_size);
639 		*size_needed += buffer_size;
640 
641 		ACPI_DEBUG_PRINT((ACPI_DB_RESOURCES,
642 				  "Type %.2X, AmlLength %.2X InternalLength %.2X\n",
643 				  acpi_ut_get_resource_type(aml_buffer),
644 				  acpi_ut_get_descriptor_length(aml_buffer),
645 				  buffer_size));
646 
647 		/*
648 		 * Point to the next resource within the AML stream using the length
649 		 * contained in the resource descriptor header
650 		 */
651 		aml_buffer += acpi_ut_get_descriptor_length(aml_buffer);
652 	}
653 
654 	/* Did not find an end_tag resource descriptor */
655 
656 	return_ACPI_STATUS(AE_AML_NO_RESOURCE_END_TAG);
657 }
658 
659 /*******************************************************************************
660  *
661  * FUNCTION:    acpi_rs_get_pci_routing_table_length
662  *
663  * PARAMETERS:  package_object          - Pointer to the package object
664  *              buffer_size_needed      - u32 pointer of the size buffer
665  *                                        needed to properly return the
666  *                                        parsed data
667  *
668  * RETURN:      Status
669  *
670  * DESCRIPTION: Given a package representing a PCI routing table, this
671  *              calculates the size of the corresponding linked list of
672  *              descriptions.
673  *
674  ******************************************************************************/
675 
676 acpi_status
677 acpi_rs_get_pci_routing_table_length(union acpi_operand_object *package_object,
678 				     acpi_size *buffer_size_needed)
679 {
680 	u32 number_of_elements;
681 	acpi_size temp_size_needed = 0;
682 	union acpi_operand_object **top_object_list;
683 	u32 index;
684 	union acpi_operand_object *package_element;
685 	union acpi_operand_object **sub_object_list;
686 	u8 name_found;
687 	u32 table_index;
688 
689 	ACPI_FUNCTION_TRACE(rs_get_pci_routing_table_length);
690 
691 	number_of_elements = package_object->package.count;
692 
693 	/*
694 	 * Calculate the size of the return buffer.
695 	 * The base size is the number of elements * the sizes of the
696 	 * structures. Additional space for the strings is added below.
697 	 * The minus one is to subtract the size of the u8 Source[1]
698 	 * member because it is added below.
699 	 *
700 	 * But each PRT_ENTRY structure has a pointer to a string and
701 	 * the size of that string must be found.
702 	 */
703 	top_object_list = package_object->package.elements;
704 
705 	for (index = 0; index < number_of_elements; index++) {
706 
707 		/* Dereference the subpackage */
708 
709 		package_element = *top_object_list;
710 
711 		/* We must have a valid Package object */
712 
713 		if (!package_element ||
714 		    (package_element->common.type != ACPI_TYPE_PACKAGE)) {
715 			return_ACPI_STATUS(AE_AML_OPERAND_TYPE);
716 		}
717 
718 		/*
719 		 * The sub_object_list will now point to an array of the
720 		 * four IRQ elements: Address, Pin, Source and source_index
721 		 */
722 		sub_object_list = package_element->package.elements;
723 
724 		/* Scan the irq_table_elements for the Source Name String */
725 
726 		name_found = FALSE;
727 
728 		for (table_index = 0;
729 		     table_index < package_element->package.count
730 		     && !name_found; table_index++) {
731 			if (*sub_object_list &&	/* Null object allowed */
732 			    ((ACPI_TYPE_STRING ==
733 			      (*sub_object_list)->common.type) ||
734 			     ((ACPI_TYPE_LOCAL_REFERENCE ==
735 			       (*sub_object_list)->common.type) &&
736 			      ((*sub_object_list)->reference.class ==
737 			       ACPI_REFCLASS_NAME)))) {
738 				name_found = TRUE;
739 			} else {
740 				/* Look at the next element */
741 
742 				sub_object_list++;
743 			}
744 		}
745 
746 		temp_size_needed += (sizeof(struct acpi_pci_routing_table) - 4);
747 
748 		/* Was a String type found? */
749 
750 		if (name_found) {
751 			if ((*sub_object_list)->common.type == ACPI_TYPE_STRING) {
752 				/*
753 				 * The length String.Length field does not include the
754 				 * terminating NULL, add 1
755 				 */
756 				temp_size_needed += ((acpi_size)
757 						     (*sub_object_list)->string.
758 						     length + 1);
759 			} else {
760 				temp_size_needed += acpi_ns_get_pathname_length((*sub_object_list)->reference.node);
761 			}
762 		} else {
763 			/*
764 			 * If no name was found, then this is a NULL, which is
765 			 * translated as a u32 zero.
766 			 */
767 			temp_size_needed += sizeof(u32);
768 		}
769 
770 		/* Round up the size since each element must be aligned */
771 
772 		temp_size_needed = ACPI_ROUND_UP_TO_64BIT(temp_size_needed);
773 
774 		/* Point to the next union acpi_operand_object */
775 
776 		top_object_list++;
777 	}
778 
779 	/*
780 	 * Add an extra element to the end of the list, essentially a
781 	 * NULL terminator
782 	 */
783 	*buffer_size_needed =
784 	    temp_size_needed + sizeof(struct acpi_pci_routing_table);
785 	return_ACPI_STATUS(AE_OK);
786 }
787