xref: /linux/drivers/acpi/acpica/rscalc.c (revision 6e9041c6ddd6cbdc61d87bcaca8ca7bb17c28377)
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  *              size_needed         - Where the required size is returned
178  *
179  * RETURN:      Status
180  *
181  * DESCRIPTION: Takes a linked list of internal resource descriptors and
182  *              calculates the size buffer needed to hold the corresponding
183  *              external resource byte stream.
184  *
185  ******************************************************************************/
186 
187 acpi_status
188 acpi_rs_get_aml_length(struct acpi_resource * resource, acpi_size * size_needed)
189 {
190 	acpi_size aml_size_needed = 0;
191 	acpi_rs_length total_size;
192 
193 	ACPI_FUNCTION_TRACE(rs_get_aml_length);
194 
195 	/* Traverse entire list of internal resource descriptors */
196 
197 	while (resource) {
198 
199 		/* Validate the descriptor type */
200 
201 		if (resource->type > ACPI_RESOURCE_TYPE_MAX) {
202 			return_ACPI_STATUS(AE_AML_INVALID_RESOURCE_TYPE);
203 		}
204 
205 		/* Sanity check the length. It must not be zero, or we loop forever */
206 
207 		if (!resource->length) {
208 			return_ACPI_STATUS(AE_AML_BAD_RESOURCE_LENGTH);
209 		}
210 
211 		/* Get the base size of the (external stream) resource descriptor */
212 
213 		total_size = acpi_gbl_aml_resource_sizes[resource->type];
214 
215 		/*
216 		 * Augment the base size for descriptors with optional and/or
217 		 * variable-length fields
218 		 */
219 		switch (resource->type) {
220 		case ACPI_RESOURCE_TYPE_IRQ:
221 
222 			/* Length can be 3 or 2 */
223 
224 			if (resource->data.irq.descriptor_length == 2) {
225 				total_size--;
226 			}
227 			break;
228 
229 		case ACPI_RESOURCE_TYPE_START_DEPENDENT:
230 
231 			/* Length can be 1 or 0 */
232 
233 			if (resource->data.irq.descriptor_length == 0) {
234 				total_size--;
235 			}
236 			break;
237 
238 		case ACPI_RESOURCE_TYPE_VENDOR:
239 			/*
240 			 * Vendor Defined Resource:
241 			 * For a Vendor Specific resource, if the Length is between 1 and 7
242 			 * it will be created as a Small Resource data type, otherwise it
243 			 * is a Large Resource data type.
244 			 */
245 			if (resource->data.vendor.byte_length > 7) {
246 
247 				/* Base size of a Large resource descriptor */
248 
249 				total_size =
250 				    sizeof(struct aml_resource_large_header);
251 			}
252 
253 			/* Add the size of the vendor-specific data */
254 
255 			total_size = (acpi_rs_length)
256 			    (total_size + resource->data.vendor.byte_length);
257 			break;
258 
259 		case ACPI_RESOURCE_TYPE_END_TAG:
260 			/*
261 			 * End Tag:
262 			 * We are done -- return the accumulated total size.
263 			 */
264 			*size_needed = aml_size_needed + total_size;
265 
266 			/* Normal exit */
267 
268 			return_ACPI_STATUS(AE_OK);
269 
270 		case ACPI_RESOURCE_TYPE_ADDRESS16:
271 			/*
272 			 * 16-Bit Address Resource:
273 			 * Add the size of the optional resource_source info
274 			 */
275 			total_size = (acpi_rs_length)
276 			    (total_size +
277 			     acpi_rs_struct_option_length(&resource->data.
278 							  address16.
279 							  resource_source));
280 			break;
281 
282 		case ACPI_RESOURCE_TYPE_ADDRESS32:
283 			/*
284 			 * 32-Bit Address Resource:
285 			 * Add the size of the optional resource_source info
286 			 */
287 			total_size = (acpi_rs_length)
288 			    (total_size +
289 			     acpi_rs_struct_option_length(&resource->data.
290 							  address32.
291 							  resource_source));
292 			break;
293 
294 		case ACPI_RESOURCE_TYPE_ADDRESS64:
295 			/*
296 			 * 64-Bit Address Resource:
297 			 * Add the size of the optional resource_source info
298 			 */
299 			total_size = (acpi_rs_length)
300 			    (total_size +
301 			     acpi_rs_struct_option_length(&resource->data.
302 							  address64.
303 							  resource_source));
304 			break;
305 
306 		case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
307 			/*
308 			 * Extended IRQ Resource:
309 			 * Add the size of each additional optional interrupt beyond the
310 			 * required 1 (4 bytes for each u32 interrupt number)
311 			 */
312 			total_size = (acpi_rs_length)
313 			    (total_size +
314 			     ((resource->data.extended_irq.interrupt_count -
315 			       1) * 4) +
316 			     /* Add the size of the optional resource_source info */
317 			     acpi_rs_struct_option_length(&resource->data.
318 							  extended_irq.
319 							  resource_source));
320 			break;
321 
322 		case ACPI_RESOURCE_TYPE_GPIO:
323 
324 			total_size =
325 			    (acpi_rs_length) (total_size +
326 					      (resource->data.gpio.
327 					       pin_table_length * 2) +
328 					      resource->data.gpio.
329 					      resource_source.string_length +
330 					      resource->data.gpio.
331 					      vendor_length);
332 
333 			break;
334 
335 		case ACPI_RESOURCE_TYPE_SERIAL_BUS:
336 
337 			total_size =
338 			    acpi_gbl_aml_resource_serial_bus_sizes[resource->
339 								   data.
340 								   common_serial_bus.
341 								   type];
342 
343 			total_size = (acpi_rs_length) (total_size +
344 						       resource->data.
345 						       i2c_serial_bus.
346 						       resource_source.
347 						       string_length +
348 						       resource->data.
349 						       i2c_serial_bus.
350 						       vendor_length);
351 
352 			break;
353 
354 		default:
355 			break;
356 		}
357 
358 		/* Update the total */
359 
360 		aml_size_needed += total_size;
361 
362 		/* Point to the next object */
363 
364 		resource =
365 		    ACPI_ADD_PTR(struct acpi_resource, resource,
366 				 resource->length);
367 	}
368 
369 	/* Did not find an end_tag resource descriptor */
370 
371 	return_ACPI_STATUS(AE_AML_NO_RESOURCE_END_TAG);
372 }
373 
374 /*******************************************************************************
375  *
376  * FUNCTION:    acpi_rs_get_list_length
377  *
378  * PARAMETERS:  aml_buffer          - Pointer to the resource byte stream
379  *              aml_buffer_length   - Size of aml_buffer
380  *              size_needed         - Where the size needed is returned
381  *
382  * RETURN:      Status
383  *
384  * DESCRIPTION: Takes an external resource byte stream and calculates the size
385  *              buffer needed to hold the corresponding internal resource
386  *              descriptor linked list.
387  *
388  ******************************************************************************/
389 
390 acpi_status
391 acpi_rs_get_list_length(u8 * aml_buffer,
392 			u32 aml_buffer_length, acpi_size * size_needed)
393 {
394 	acpi_status status;
395 	u8 *end_aml;
396 	u8 *buffer;
397 	u32 buffer_size;
398 	u16 temp16;
399 	u16 resource_length;
400 	u32 extra_struct_bytes;
401 	u8 resource_index;
402 	u8 minimum_aml_resource_length;
403 	union aml_resource *aml_resource;
404 
405 	ACPI_FUNCTION_TRACE(rs_get_list_length);
406 
407 	*size_needed = ACPI_RS_SIZE_MIN;	/* Minimum size is one end_tag */
408 	end_aml = aml_buffer + aml_buffer_length;
409 
410 	/* Walk the list of AML resource descriptors */
411 
412 	while (aml_buffer < end_aml) {
413 
414 		/* Validate the Resource Type and Resource Length */
415 
416 		status =
417 		    acpi_ut_validate_resource(NULL, aml_buffer,
418 					      &resource_index);
419 		if (ACPI_FAILURE(status)) {
420 			/*
421 			 * Exit on failure. Cannot continue because the descriptor length
422 			 * may be bogus also.
423 			 */
424 			return_ACPI_STATUS(status);
425 		}
426 
427 		aml_resource = (void *)aml_buffer;
428 
429 		/* Get the resource length and base (minimum) AML size */
430 
431 		resource_length = acpi_ut_get_resource_length(aml_buffer);
432 		minimum_aml_resource_length =
433 		    acpi_gbl_resource_aml_sizes[resource_index];
434 
435 		/*
436 		 * Augment the size for descriptors with optional
437 		 * and/or variable length fields
438 		 */
439 		extra_struct_bytes = 0;
440 		buffer =
441 		    aml_buffer + acpi_ut_get_resource_header_length(aml_buffer);
442 
443 		switch (acpi_ut_get_resource_type(aml_buffer)) {
444 		case ACPI_RESOURCE_NAME_IRQ:
445 			/*
446 			 * IRQ Resource:
447 			 * Get the number of bits set in the 16-bit IRQ mask
448 			 */
449 			ACPI_MOVE_16_TO_16(&temp16, buffer);
450 			extra_struct_bytes = acpi_rs_count_set_bits(temp16);
451 			break;
452 
453 		case ACPI_RESOURCE_NAME_DMA:
454 			/*
455 			 * DMA Resource:
456 			 * Get the number of bits set in the 8-bit DMA mask
457 			 */
458 			extra_struct_bytes = acpi_rs_count_set_bits(*buffer);
459 			break;
460 
461 		case ACPI_RESOURCE_NAME_VENDOR_SMALL:
462 		case ACPI_RESOURCE_NAME_VENDOR_LARGE:
463 			/*
464 			 * Vendor Resource:
465 			 * Get the number of vendor data bytes
466 			 */
467 			extra_struct_bytes = resource_length;
468 
469 			/*
470 			 * There is already one byte included in the minimum
471 			 * descriptor size. If there are extra struct bytes,
472 			 * subtract one from the count.
473 			 */
474 			if (extra_struct_bytes) {
475 				extra_struct_bytes--;
476 			}
477 			break;
478 
479 		case ACPI_RESOURCE_NAME_END_TAG:
480 			/*
481 			 * End Tag: This is the normal exit
482 			 */
483 			return_ACPI_STATUS(AE_OK);
484 
485 		case ACPI_RESOURCE_NAME_ADDRESS32:
486 		case ACPI_RESOURCE_NAME_ADDRESS16:
487 		case ACPI_RESOURCE_NAME_ADDRESS64:
488 			/*
489 			 * Address Resource:
490 			 * Add the size of the optional resource_source
491 			 */
492 			extra_struct_bytes =
493 			    acpi_rs_stream_option_length(resource_length,
494 							 minimum_aml_resource_length);
495 			break;
496 
497 		case ACPI_RESOURCE_NAME_EXTENDED_IRQ:
498 			/*
499 			 * Extended IRQ Resource:
500 			 * Using the interrupt_table_length, add 4 bytes for each additional
501 			 * interrupt. Note: at least one interrupt is required and is
502 			 * included in the minimum descriptor size (reason for the -1)
503 			 */
504 			extra_struct_bytes = (buffer[1] - 1) * sizeof(u32);
505 
506 			/* Add the size of the optional resource_source */
507 
508 			extra_struct_bytes +=
509 			    acpi_rs_stream_option_length(resource_length -
510 							 extra_struct_bytes,
511 							 minimum_aml_resource_length);
512 			break;
513 
514 		case ACPI_RESOURCE_NAME_GPIO:
515 
516 			/* Vendor data is optional */
517 
518 			if (aml_resource->gpio.vendor_length) {
519 				extra_struct_bytes +=
520 				    aml_resource->gpio.vendor_offset -
521 				    aml_resource->gpio.pin_table_offset +
522 				    aml_resource->gpio.vendor_length;
523 			} else {
524 				extra_struct_bytes +=
525 				    aml_resource->large_header.resource_length +
526 				    sizeof(struct aml_resource_large_header) -
527 				    aml_resource->gpio.pin_table_offset;
528 			}
529 			break;
530 
531 		case ACPI_RESOURCE_NAME_SERIAL_BUS:
532 
533 			minimum_aml_resource_length =
534 			    acpi_gbl_resource_aml_serial_bus_sizes
535 			    [aml_resource->common_serial_bus.type];
536 			extra_struct_bytes +=
537 			    aml_resource->common_serial_bus.resource_length -
538 			    minimum_aml_resource_length;
539 			break;
540 
541 		default:
542 			break;
543 		}
544 
545 		/*
546 		 * Update the required buffer size for the internal descriptor structs
547 		 *
548 		 * Important: Round the size up for the appropriate alignment. This
549 		 * is a requirement on IA64.
550 		 */
551 		if (acpi_ut_get_resource_type(aml_buffer) ==
552 		    ACPI_RESOURCE_NAME_SERIAL_BUS) {
553 			buffer_size =
554 			    acpi_gbl_resource_struct_serial_bus_sizes
555 			    [aml_resource->common_serial_bus.type] +
556 			    extra_struct_bytes;
557 		} else {
558 			buffer_size =
559 			    acpi_gbl_resource_struct_sizes[resource_index] +
560 			    extra_struct_bytes;
561 		}
562 		buffer_size = (u32)ACPI_ROUND_UP_TO_NATIVE_WORD(buffer_size);
563 
564 		*size_needed += buffer_size;
565 
566 		ACPI_DEBUG_PRINT((ACPI_DB_RESOURCES,
567 				  "Type %.2X, AmlLength %.2X InternalLength %.2X\n",
568 				  acpi_ut_get_resource_type(aml_buffer),
569 				  acpi_ut_get_descriptor_length(aml_buffer),
570 				  buffer_size));
571 
572 		/*
573 		 * Point to the next resource within the AML stream using the length
574 		 * contained in the resource descriptor header
575 		 */
576 		aml_buffer += acpi_ut_get_descriptor_length(aml_buffer);
577 	}
578 
579 	/* Did not find an end_tag resource descriptor */
580 
581 	return_ACPI_STATUS(AE_AML_NO_RESOURCE_END_TAG);
582 }
583 
584 /*******************************************************************************
585  *
586  * FUNCTION:    acpi_rs_get_pci_routing_table_length
587  *
588  * PARAMETERS:  package_object          - Pointer to the package object
589  *              buffer_size_needed      - u32 pointer of the size buffer
590  *                                        needed to properly return the
591  *                                        parsed data
592  *
593  * RETURN:      Status
594  *
595  * DESCRIPTION: Given a package representing a PCI routing table, this
596  *              calculates the size of the corresponding linked list of
597  *              descriptions.
598  *
599  ******************************************************************************/
600 
601 acpi_status
602 acpi_rs_get_pci_routing_table_length(union acpi_operand_object *package_object,
603 				     acpi_size * buffer_size_needed)
604 {
605 	u32 number_of_elements;
606 	acpi_size temp_size_needed = 0;
607 	union acpi_operand_object **top_object_list;
608 	u32 index;
609 	union acpi_operand_object *package_element;
610 	union acpi_operand_object **sub_object_list;
611 	u8 name_found;
612 	u32 table_index;
613 
614 	ACPI_FUNCTION_TRACE(rs_get_pci_routing_table_length);
615 
616 	number_of_elements = package_object->package.count;
617 
618 	/*
619 	 * Calculate the size of the return buffer.
620 	 * The base size is the number of elements * the sizes of the
621 	 * structures. Additional space for the strings is added below.
622 	 * The minus one is to subtract the size of the u8 Source[1]
623 	 * member because it is added below.
624 	 *
625 	 * But each PRT_ENTRY structure has a pointer to a string and
626 	 * the size of that string must be found.
627 	 */
628 	top_object_list = package_object->package.elements;
629 
630 	for (index = 0; index < number_of_elements; index++) {
631 
632 		/* Dereference the sub-package */
633 
634 		package_element = *top_object_list;
635 
636 		/* We must have a valid Package object */
637 
638 		if (!package_element ||
639 		    (package_element->common.type != ACPI_TYPE_PACKAGE)) {
640 			return_ACPI_STATUS(AE_AML_OPERAND_TYPE);
641 		}
642 
643 		/*
644 		 * The sub_object_list will now point to an array of the
645 		 * four IRQ elements: Address, Pin, Source and source_index
646 		 */
647 		sub_object_list = package_element->package.elements;
648 
649 		/* Scan the irq_table_elements for the Source Name String */
650 
651 		name_found = FALSE;
652 
653 		for (table_index = 0; table_index < 4 && !name_found;
654 		     table_index++) {
655 			if (*sub_object_list &&	/* Null object allowed */
656 			    ((ACPI_TYPE_STRING ==
657 			      (*sub_object_list)->common.type) ||
658 			     ((ACPI_TYPE_LOCAL_REFERENCE ==
659 			       (*sub_object_list)->common.type) &&
660 			      ((*sub_object_list)->reference.class ==
661 			       ACPI_REFCLASS_NAME)))) {
662 				name_found = TRUE;
663 			} else {
664 				/* Look at the next element */
665 
666 				sub_object_list++;
667 			}
668 		}
669 
670 		temp_size_needed += (sizeof(struct acpi_pci_routing_table) - 4);
671 
672 		/* Was a String type found? */
673 
674 		if (name_found) {
675 			if ((*sub_object_list)->common.type == ACPI_TYPE_STRING) {
676 				/*
677 				 * The length String.Length field does not include the
678 				 * terminating NULL, add 1
679 				 */
680 				temp_size_needed += ((acpi_size)
681 						     (*sub_object_list)->string.
682 						     length + 1);
683 			} else {
684 				temp_size_needed += acpi_ns_get_pathname_length((*sub_object_list)->reference.node);
685 			}
686 		} else {
687 			/*
688 			 * If no name was found, then this is a NULL, which is
689 			 * translated as a u32 zero.
690 			 */
691 			temp_size_needed += sizeof(u32);
692 		}
693 
694 		/* Round up the size since each element must be aligned */
695 
696 		temp_size_needed = ACPI_ROUND_UP_TO_64BIT(temp_size_needed);
697 
698 		/* Point to the next union acpi_operand_object */
699 
700 		top_object_list++;
701 	}
702 
703 	/*
704 	 * Add an extra element to the end of the list, essentially a
705 	 * NULL terminator
706 	 */
707 	*buffer_size_needed =
708 	    temp_size_needed + sizeof(struct acpi_pci_routing_table);
709 	return_ACPI_STATUS(AE_OK);
710 }
711