xref: /linux/drivers/acpi/acpica/rscalc.c (revision 9a0a3597)
1 /*******************************************************************************
2  *
3  * Module Name: rscalc - Calculate stream and list lengths
4  *
5  ******************************************************************************/
6 
7 /*
8  * Copyright (C) 2000 - 2013, 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 some
147 	 * Large-type resource descriptors.
148 	 */
149 
150 	/*
151 	 * If the length of the actual resource descriptor is greater than the ACPI
152 	 * spec-defined minimum length, it means that a resource_source_index exists
153 	 * and is followed by a (required) null terminated string. The string length
154 	 * (including the null terminator) is the resource length minus the minimum
155 	 * length, minus one byte for the resource_source_index itself.
156 	 */
157 	if (resource_length > minimum_aml_resource_length) {
158 
159 		/* Compute the length of the optional string */
160 
161 		string_length =
162 		    resource_length - minimum_aml_resource_length - 1;
163 	}
164 
165 	/*
166 	 * Round the length up to a multiple of the native word in order to
167 	 * guarantee that the entire resource descriptor is native word aligned
168 	 */
169 	return ((u32) ACPI_ROUND_UP_TO_NATIVE_WORD(string_length));
170 }
171 
172 /*******************************************************************************
173  *
174  * FUNCTION:    acpi_rs_get_aml_length
175  *
176  * PARAMETERS:  resource            - Pointer to the resource linked list
177  *              resource_list_size  - Size of the resource linked list
178  *              size_needed         - Where the required size is returned
179  *
180  * RETURN:      Status
181  *
182  * DESCRIPTION: Takes a linked list of internal resource descriptors and
183  *              calculates the size buffer needed to hold the corresponding
184  *              external resource byte stream.
185  *
186  ******************************************************************************/
187 
188 acpi_status
189 acpi_rs_get_aml_length(struct acpi_resource *resource,
190 		       acpi_size resource_list_size, acpi_size * size_needed)
191 {
192 	acpi_size aml_size_needed = 0;
193 	struct acpi_resource *resource_end;
194 	acpi_rs_length total_size;
195 
196 	ACPI_FUNCTION_TRACE(rs_get_aml_length);
197 
198 	/* Traverse entire list of internal resource descriptors */
199 
200 	resource_end =
201 	    ACPI_ADD_PTR(struct acpi_resource, resource, resource_list_size);
202 	while (resource < resource_end) {
203 
204 		/* Validate the descriptor type */
205 
206 		if (resource->type > ACPI_RESOURCE_TYPE_MAX) {
207 			return_ACPI_STATUS(AE_AML_INVALID_RESOURCE_TYPE);
208 		}
209 
210 		/* Sanity check the length. It must not be zero, or we loop forever */
211 
212 		if (!resource->length) {
213 			return_ACPI_STATUS(AE_AML_BAD_RESOURCE_LENGTH);
214 		}
215 
216 		/* Get the base size of the (external stream) resource descriptor */
217 
218 		total_size = acpi_gbl_aml_resource_sizes[resource->type];
219 
220 		/*
221 		 * Augment the base size for descriptors with optional and/or
222 		 * variable-length fields
223 		 */
224 		switch (resource->type) {
225 		case ACPI_RESOURCE_TYPE_IRQ:
226 
227 			/* Length can be 3 or 2 */
228 
229 			if (resource->data.irq.descriptor_length == 2) {
230 				total_size--;
231 			}
232 			break;
233 
234 		case ACPI_RESOURCE_TYPE_START_DEPENDENT:
235 
236 			/* Length can be 1 or 0 */
237 
238 			if (resource->data.irq.descriptor_length == 0) {
239 				total_size--;
240 			}
241 			break;
242 
243 		case ACPI_RESOURCE_TYPE_VENDOR:
244 			/*
245 			 * Vendor Defined Resource:
246 			 * For a Vendor Specific resource, if the Length is between 1 and 7
247 			 * it will be created as a Small Resource data type, otherwise it
248 			 * is a Large Resource data type.
249 			 */
250 			if (resource->data.vendor.byte_length > 7) {
251 
252 				/* Base size of a Large resource descriptor */
253 
254 				total_size =
255 				    sizeof(struct aml_resource_large_header);
256 			}
257 
258 			/* Add the size of the vendor-specific data */
259 
260 			total_size = (acpi_rs_length)
261 			    (total_size + resource->data.vendor.byte_length);
262 			break;
263 
264 		case ACPI_RESOURCE_TYPE_END_TAG:
265 			/*
266 			 * End Tag:
267 			 * We are done -- return the accumulated total size.
268 			 */
269 			*size_needed = aml_size_needed + total_size;
270 
271 			/* Normal exit */
272 
273 			return_ACPI_STATUS(AE_OK);
274 
275 		case ACPI_RESOURCE_TYPE_ADDRESS16:
276 			/*
277 			 * 16-Bit Address Resource:
278 			 * Add the size of the optional resource_source info
279 			 */
280 			total_size = (acpi_rs_length)
281 			    (total_size +
282 			     acpi_rs_struct_option_length(&resource->data.
283 							  address16.
284 							  resource_source));
285 			break;
286 
287 		case ACPI_RESOURCE_TYPE_ADDRESS32:
288 			/*
289 			 * 32-Bit Address Resource:
290 			 * Add the size of the optional resource_source info
291 			 */
292 			total_size = (acpi_rs_length)
293 			    (total_size +
294 			     acpi_rs_struct_option_length(&resource->data.
295 							  address32.
296 							  resource_source));
297 			break;
298 
299 		case ACPI_RESOURCE_TYPE_ADDRESS64:
300 			/*
301 			 * 64-Bit Address Resource:
302 			 * Add the size of the optional resource_source info
303 			 */
304 			total_size = (acpi_rs_length)
305 			    (total_size +
306 			     acpi_rs_struct_option_length(&resource->data.
307 							  address64.
308 							  resource_source));
309 			break;
310 
311 		case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
312 			/*
313 			 * Extended IRQ Resource:
314 			 * Add the size of each additional optional interrupt beyond the
315 			 * required 1 (4 bytes for each u32 interrupt number)
316 			 */
317 			total_size = (acpi_rs_length)
318 			    (total_size +
319 			     ((resource->data.extended_irq.interrupt_count -
320 			       1) * 4) +
321 			     /* Add the size of the optional resource_source info */
322 			     acpi_rs_struct_option_length(&resource->data.
323 							  extended_irq.
324 							  resource_source));
325 			break;
326 
327 		case ACPI_RESOURCE_TYPE_GPIO:
328 
329 			total_size =
330 			    (acpi_rs_length) (total_size +
331 					      (resource->data.gpio.
332 					       pin_table_length * 2) +
333 					      resource->data.gpio.
334 					      resource_source.string_length +
335 					      resource->data.gpio.
336 					      vendor_length);
337 
338 			break;
339 
340 		case ACPI_RESOURCE_TYPE_SERIAL_BUS:
341 
342 			total_size =
343 			    acpi_gbl_aml_resource_serial_bus_sizes[resource->
344 								   data.
345 								   common_serial_bus.
346 								   type];
347 
348 			total_size = (acpi_rs_length) (total_size +
349 						       resource->data.
350 						       i2c_serial_bus.
351 						       resource_source.
352 						       string_length +
353 						       resource->data.
354 						       i2c_serial_bus.
355 						       vendor_length);
356 
357 			break;
358 
359 		default:
360 
361 			break;
362 		}
363 
364 		/* Update the total */
365 
366 		aml_size_needed += total_size;
367 
368 		/* Point to the next object */
369 
370 		resource =
371 		    ACPI_ADD_PTR(struct acpi_resource, resource,
372 				 resource->length);
373 	}
374 
375 	/* Did not find an end_tag resource descriptor */
376 
377 	return_ACPI_STATUS(AE_AML_NO_RESOURCE_END_TAG);
378 }
379 
380 /*******************************************************************************
381  *
382  * FUNCTION:    acpi_rs_get_list_length
383  *
384  * PARAMETERS:  aml_buffer          - Pointer to the resource byte stream
385  *              aml_buffer_length   - Size of aml_buffer
386  *              size_needed         - Where the size needed is returned
387  *
388  * RETURN:      Status
389  *
390  * DESCRIPTION: Takes an external resource byte stream and calculates the size
391  *              buffer needed to hold the corresponding internal resource
392  *              descriptor linked list.
393  *
394  ******************************************************************************/
395 
396 acpi_status
397 acpi_rs_get_list_length(u8 * aml_buffer,
398 			u32 aml_buffer_length, acpi_size * size_needed)
399 {
400 	acpi_status status;
401 	u8 *end_aml;
402 	u8 *buffer;
403 	u32 buffer_size;
404 	u16 temp16;
405 	u16 resource_length;
406 	u32 extra_struct_bytes;
407 	u8 resource_index;
408 	u8 minimum_aml_resource_length;
409 	union aml_resource *aml_resource;
410 
411 	ACPI_FUNCTION_TRACE(rs_get_list_length);
412 
413 	*size_needed = ACPI_RS_SIZE_MIN;	/* Minimum size is one end_tag */
414 	end_aml = aml_buffer + aml_buffer_length;
415 
416 	/* Walk the list of AML resource descriptors */
417 
418 	while (aml_buffer < end_aml) {
419 
420 		/* Validate the Resource Type and Resource Length */
421 
422 		status =
423 		    acpi_ut_validate_resource(NULL, aml_buffer,
424 					      &resource_index);
425 		if (ACPI_FAILURE(status)) {
426 			/*
427 			 * Exit on failure. Cannot continue because the descriptor length
428 			 * may be bogus also.
429 			 */
430 			return_ACPI_STATUS(status);
431 		}
432 
433 		aml_resource = (void *)aml_buffer;
434 
435 		/* Get the resource length and base (minimum) AML size */
436 
437 		resource_length = acpi_ut_get_resource_length(aml_buffer);
438 		minimum_aml_resource_length =
439 		    acpi_gbl_resource_aml_sizes[resource_index];
440 
441 		/*
442 		 * Augment the size for descriptors with optional
443 		 * and/or variable length fields
444 		 */
445 		extra_struct_bytes = 0;
446 		buffer =
447 		    aml_buffer + acpi_ut_get_resource_header_length(aml_buffer);
448 
449 		switch (acpi_ut_get_resource_type(aml_buffer)) {
450 		case ACPI_RESOURCE_NAME_IRQ:
451 			/*
452 			 * IRQ Resource:
453 			 * Get the number of bits set in the 16-bit IRQ mask
454 			 */
455 			ACPI_MOVE_16_TO_16(&temp16, buffer);
456 			extra_struct_bytes = acpi_rs_count_set_bits(temp16);
457 			break;
458 
459 		case ACPI_RESOURCE_NAME_DMA:
460 			/*
461 			 * DMA Resource:
462 			 * Get the number of bits set in the 8-bit DMA mask
463 			 */
464 			extra_struct_bytes = acpi_rs_count_set_bits(*buffer);
465 			break;
466 
467 		case ACPI_RESOURCE_NAME_VENDOR_SMALL:
468 		case ACPI_RESOURCE_NAME_VENDOR_LARGE:
469 			/*
470 			 * Vendor Resource:
471 			 * Get the number of vendor data bytes
472 			 */
473 			extra_struct_bytes = resource_length;
474 
475 			/*
476 			 * There is already one byte included in the minimum
477 			 * descriptor size. If there are extra struct bytes,
478 			 * subtract one from the count.
479 			 */
480 			if (extra_struct_bytes) {
481 				extra_struct_bytes--;
482 			}
483 			break;
484 
485 		case ACPI_RESOURCE_NAME_END_TAG:
486 			/*
487 			 * End Tag: This is the normal exit
488 			 */
489 			return_ACPI_STATUS(AE_OK);
490 
491 		case ACPI_RESOURCE_NAME_ADDRESS32:
492 		case ACPI_RESOURCE_NAME_ADDRESS16:
493 		case ACPI_RESOURCE_NAME_ADDRESS64:
494 			/*
495 			 * Address Resource:
496 			 * Add the size of the optional resource_source
497 			 */
498 			extra_struct_bytes =
499 			    acpi_rs_stream_option_length(resource_length,
500 							 minimum_aml_resource_length);
501 			break;
502 
503 		case ACPI_RESOURCE_NAME_EXTENDED_IRQ:
504 			/*
505 			 * Extended IRQ Resource:
506 			 * Using the interrupt_table_length, add 4 bytes for each additional
507 			 * interrupt. Note: at least one interrupt is required and is
508 			 * included in the minimum descriptor size (reason for the -1)
509 			 */
510 			extra_struct_bytes = (buffer[1] - 1) * sizeof(u32);
511 
512 			/* Add the size of the optional resource_source */
513 
514 			extra_struct_bytes +=
515 			    acpi_rs_stream_option_length(resource_length -
516 							 extra_struct_bytes,
517 							 minimum_aml_resource_length);
518 			break;
519 
520 		case ACPI_RESOURCE_NAME_GPIO:
521 
522 			/* Vendor data is optional */
523 
524 			if (aml_resource->gpio.vendor_length) {
525 				extra_struct_bytes +=
526 				    aml_resource->gpio.vendor_offset -
527 				    aml_resource->gpio.pin_table_offset +
528 				    aml_resource->gpio.vendor_length;
529 			} else {
530 				extra_struct_bytes +=
531 				    aml_resource->large_header.resource_length +
532 				    sizeof(struct aml_resource_large_header) -
533 				    aml_resource->gpio.pin_table_offset;
534 			}
535 			break;
536 
537 		case ACPI_RESOURCE_NAME_SERIAL_BUS:
538 
539 			minimum_aml_resource_length =
540 			    acpi_gbl_resource_aml_serial_bus_sizes
541 			    [aml_resource->common_serial_bus.type];
542 			extra_struct_bytes +=
543 			    aml_resource->common_serial_bus.resource_length -
544 			    minimum_aml_resource_length;
545 			break;
546 
547 		default:
548 
549 			break;
550 		}
551 
552 		/*
553 		 * Update the required buffer size for the internal descriptor structs
554 		 *
555 		 * Important: Round the size up for the appropriate alignment. This
556 		 * is a requirement on IA64.
557 		 */
558 		if (acpi_ut_get_resource_type(aml_buffer) ==
559 		    ACPI_RESOURCE_NAME_SERIAL_BUS) {
560 			buffer_size =
561 			    acpi_gbl_resource_struct_serial_bus_sizes
562 			    [aml_resource->common_serial_bus.type] +
563 			    extra_struct_bytes;
564 		} else {
565 			buffer_size =
566 			    acpi_gbl_resource_struct_sizes[resource_index] +
567 			    extra_struct_bytes;
568 		}
569 		buffer_size = (u32)ACPI_ROUND_UP_TO_NATIVE_WORD(buffer_size);
570 
571 		*size_needed += buffer_size;
572 
573 		ACPI_DEBUG_PRINT((ACPI_DB_RESOURCES,
574 				  "Type %.2X, AmlLength %.2X InternalLength %.2X\n",
575 				  acpi_ut_get_resource_type(aml_buffer),
576 				  acpi_ut_get_descriptor_length(aml_buffer),
577 				  buffer_size));
578 
579 		/*
580 		 * Point to the next resource within the AML stream using the length
581 		 * contained in the resource descriptor header
582 		 */
583 		aml_buffer += acpi_ut_get_descriptor_length(aml_buffer);
584 	}
585 
586 	/* Did not find an end_tag resource descriptor */
587 
588 	return_ACPI_STATUS(AE_AML_NO_RESOURCE_END_TAG);
589 }
590 
591 /*******************************************************************************
592  *
593  * FUNCTION:    acpi_rs_get_pci_routing_table_length
594  *
595  * PARAMETERS:  package_object          - Pointer to the package object
596  *              buffer_size_needed      - u32 pointer of the size buffer
597  *                                        needed to properly return the
598  *                                        parsed data
599  *
600  * RETURN:      Status
601  *
602  * DESCRIPTION: Given a package representing a PCI routing table, this
603  *              calculates the size of the corresponding linked list of
604  *              descriptions.
605  *
606  ******************************************************************************/
607 
608 acpi_status
609 acpi_rs_get_pci_routing_table_length(union acpi_operand_object *package_object,
610 				     acpi_size * buffer_size_needed)
611 {
612 	u32 number_of_elements;
613 	acpi_size temp_size_needed = 0;
614 	union acpi_operand_object **top_object_list;
615 	u32 index;
616 	union acpi_operand_object *package_element;
617 	union acpi_operand_object **sub_object_list;
618 	u8 name_found;
619 	u32 table_index;
620 
621 	ACPI_FUNCTION_TRACE(rs_get_pci_routing_table_length);
622 
623 	number_of_elements = package_object->package.count;
624 
625 	/*
626 	 * Calculate the size of the return buffer.
627 	 * The base size is the number of elements * the sizes of the
628 	 * structures. Additional space for the strings is added below.
629 	 * The minus one is to subtract the size of the u8 Source[1]
630 	 * member because it is added below.
631 	 *
632 	 * But each PRT_ENTRY structure has a pointer to a string and
633 	 * the size of that string must be found.
634 	 */
635 	top_object_list = package_object->package.elements;
636 
637 	for (index = 0; index < number_of_elements; index++) {
638 
639 		/* Dereference the sub-package */
640 
641 		package_element = *top_object_list;
642 
643 		/* We must have a valid Package object */
644 
645 		if (!package_element ||
646 		    (package_element->common.type != ACPI_TYPE_PACKAGE)) {
647 			return_ACPI_STATUS(AE_AML_OPERAND_TYPE);
648 		}
649 
650 		/*
651 		 * The sub_object_list will now point to an array of the
652 		 * four IRQ elements: Address, Pin, Source and source_index
653 		 */
654 		sub_object_list = package_element->package.elements;
655 
656 		/* Scan the irq_table_elements for the Source Name String */
657 
658 		name_found = FALSE;
659 
660 		for (table_index = 0;
661 		     table_index < package_element->package.count
662 		     && !name_found; table_index++) {
663 			if (*sub_object_list &&	/* Null object allowed */
664 			    ((ACPI_TYPE_STRING ==
665 			      (*sub_object_list)->common.type) ||
666 			     ((ACPI_TYPE_LOCAL_REFERENCE ==
667 			       (*sub_object_list)->common.type) &&
668 			      ((*sub_object_list)->reference.class ==
669 			       ACPI_REFCLASS_NAME)))) {
670 				name_found = TRUE;
671 			} else {
672 				/* Look at the next element */
673 
674 				sub_object_list++;
675 			}
676 		}
677 
678 		temp_size_needed += (sizeof(struct acpi_pci_routing_table) - 4);
679 
680 		/* Was a String type found? */
681 
682 		if (name_found) {
683 			if ((*sub_object_list)->common.type == ACPI_TYPE_STRING) {
684 				/*
685 				 * The length String.Length field does not include the
686 				 * terminating NULL, add 1
687 				 */
688 				temp_size_needed += ((acpi_size)
689 						     (*sub_object_list)->string.
690 						     length + 1);
691 			} else {
692 				temp_size_needed += acpi_ns_get_pathname_length((*sub_object_list)->reference.node);
693 			}
694 		} else {
695 			/*
696 			 * If no name was found, then this is a NULL, which is
697 			 * translated as a u32 zero.
698 			 */
699 			temp_size_needed += sizeof(u32);
700 		}
701 
702 		/* Round up the size since each element must be aligned */
703 
704 		temp_size_needed = ACPI_ROUND_UP_TO_64BIT(temp_size_needed);
705 
706 		/* Point to the next union acpi_operand_object */
707 
708 		top_object_list++;
709 	}
710 
711 	/*
712 	 * Add an extra element to the end of the list, essentially a
713 	 * NULL terminator
714 	 */
715 	*buffer_size_needed =
716 	    temp_size_needed + sizeof(struct acpi_pci_routing_table);
717 	return_ACPI_STATUS(AE_OK);
718 }
719