xref: /linux/drivers/acpi/acpica/utresrc.c (revision 827634added7f38b7d724cab1dccdb2b004c13c3)
1 /*******************************************************************************
2  *
3  * Module Name: utresrc - Resource management utilities
4  *
5  ******************************************************************************/
6 
7 /*
8  * Copyright (C) 2000 - 2015, 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 
48 #define _COMPONENT          ACPI_UTILITIES
49 ACPI_MODULE_NAME("utresrc")
50 
51 #if defined(ACPI_DEBUG_OUTPUT) || defined (ACPI_DISASSEMBLER) || defined (ACPI_DEBUGGER)
52 /*
53  * Strings used to decode resource descriptors.
54  * Used by both the disassembler and the debugger resource dump routines
55  */
56 const char *acpi_gbl_bm_decode[] = {
57 	"NotBusMaster",
58 	"BusMaster"
59 };
60 
61 const char *acpi_gbl_config_decode[] = {
62 	"0 - Good Configuration",
63 	"1 - Acceptable Configuration",
64 	"2 - Suboptimal Configuration",
65 	"3 - ***Invalid Configuration***",
66 };
67 
68 const char *acpi_gbl_consume_decode[] = {
69 	"ResourceProducer",
70 	"ResourceConsumer"
71 };
72 
73 const char *acpi_gbl_dec_decode[] = {
74 	"PosDecode",
75 	"SubDecode"
76 };
77 
78 const char *acpi_gbl_he_decode[] = {
79 	"Level",
80 	"Edge"
81 };
82 
83 const char *acpi_gbl_io_decode[] = {
84 	"Decode10",
85 	"Decode16"
86 };
87 
88 const char *acpi_gbl_ll_decode[] = {
89 	"ActiveHigh",
90 	"ActiveLow",
91 	"ActiveBoth",
92 	"Reserved"
93 };
94 
95 const char *acpi_gbl_max_decode[] = {
96 	"MaxNotFixed",
97 	"MaxFixed"
98 };
99 
100 const char *acpi_gbl_mem_decode[] = {
101 	"NonCacheable",
102 	"Cacheable",
103 	"WriteCombining",
104 	"Prefetchable"
105 };
106 
107 const char *acpi_gbl_min_decode[] = {
108 	"MinNotFixed",
109 	"MinFixed"
110 };
111 
112 const char *acpi_gbl_mtp_decode[] = {
113 	"AddressRangeMemory",
114 	"AddressRangeReserved",
115 	"AddressRangeACPI",
116 	"AddressRangeNVS"
117 };
118 
119 const char *acpi_gbl_rng_decode[] = {
120 	"InvalidRanges",
121 	"NonISAOnlyRanges",
122 	"ISAOnlyRanges",
123 	"EntireRange"
124 };
125 
126 const char *acpi_gbl_rw_decode[] = {
127 	"ReadOnly",
128 	"ReadWrite"
129 };
130 
131 const char *acpi_gbl_shr_decode[] = {
132 	"Exclusive",
133 	"Shared",
134 	"ExclusiveAndWake",	/* ACPI 5.0 */
135 	"SharedAndWake"		/* ACPI 5.0 */
136 };
137 
138 const char *acpi_gbl_siz_decode[] = {
139 	"Transfer8",
140 	"Transfer8_16",
141 	"Transfer16",
142 	"InvalidSize"
143 };
144 
145 const char *acpi_gbl_trs_decode[] = {
146 	"DenseTranslation",
147 	"SparseTranslation"
148 };
149 
150 const char *acpi_gbl_ttp_decode[] = {
151 	"TypeStatic",
152 	"TypeTranslation"
153 };
154 
155 const char *acpi_gbl_typ_decode[] = {
156 	"Compatibility",
157 	"TypeA",
158 	"TypeB",
159 	"TypeF"
160 };
161 
162 const char *acpi_gbl_ppc_decode[] = {
163 	"PullDefault",
164 	"PullUp",
165 	"PullDown",
166 	"PullNone"
167 };
168 
169 const char *acpi_gbl_ior_decode[] = {
170 	"IoRestrictionNone",
171 	"IoRestrictionInputOnly",
172 	"IoRestrictionOutputOnly",
173 	"IoRestrictionNoneAndPreserve"
174 };
175 
176 const char *acpi_gbl_dts_decode[] = {
177 	"Width8bit",
178 	"Width16bit",
179 	"Width32bit",
180 	"Width64bit",
181 	"Width128bit",
182 	"Width256bit",
183 };
184 
185 /* GPIO connection type */
186 
187 const char *acpi_gbl_ct_decode[] = {
188 	"Interrupt",
189 	"I/O"
190 };
191 
192 /* Serial bus type */
193 
194 const char *acpi_gbl_sbt_decode[] = {
195 	"/* UNKNOWN serial bus type */",
196 	"I2C",
197 	"SPI",
198 	"UART"
199 };
200 
201 /* I2C serial bus access mode */
202 
203 const char *acpi_gbl_am_decode[] = {
204 	"AddressingMode7Bit",
205 	"AddressingMode10Bit"
206 };
207 
208 /* I2C serial bus slave mode */
209 
210 const char *acpi_gbl_sm_decode[] = {
211 	"ControllerInitiated",
212 	"DeviceInitiated"
213 };
214 
215 /* SPI serial bus wire mode */
216 
217 const char *acpi_gbl_wm_decode[] = {
218 	"FourWireMode",
219 	"ThreeWireMode"
220 };
221 
222 /* SPI serial clock phase */
223 
224 const char *acpi_gbl_cph_decode[] = {
225 	"ClockPhaseFirst",
226 	"ClockPhaseSecond"
227 };
228 
229 /* SPI serial bus clock polarity */
230 
231 const char *acpi_gbl_cpo_decode[] = {
232 	"ClockPolarityLow",
233 	"ClockPolarityHigh"
234 };
235 
236 /* SPI serial bus device polarity */
237 
238 const char *acpi_gbl_dp_decode[] = {
239 	"PolarityLow",
240 	"PolarityHigh"
241 };
242 
243 /* UART serial bus endian */
244 
245 const char *acpi_gbl_ed_decode[] = {
246 	"LittleEndian",
247 	"BigEndian"
248 };
249 
250 /* UART serial bus bits per byte */
251 
252 const char *acpi_gbl_bpb_decode[] = {
253 	"DataBitsFive",
254 	"DataBitsSix",
255 	"DataBitsSeven",
256 	"DataBitsEight",
257 	"DataBitsNine",
258 	"/* UNKNOWN Bits per byte */",
259 	"/* UNKNOWN Bits per byte */",
260 	"/* UNKNOWN Bits per byte */"
261 };
262 
263 /* UART serial bus stop bits */
264 
265 const char *acpi_gbl_sb_decode[] = {
266 	"StopBitsZero",
267 	"StopBitsOne",
268 	"StopBitsOnePlusHalf",
269 	"StopBitsTwo"
270 };
271 
272 /* UART serial bus flow control */
273 
274 const char *acpi_gbl_fc_decode[] = {
275 	"FlowControlNone",
276 	"FlowControlHardware",
277 	"FlowControlXON",
278 	"/* UNKNOWN flow control keyword */"
279 };
280 
281 /* UART serial bus parity type */
282 
283 const char *acpi_gbl_pt_decode[] = {
284 	"ParityTypeNone",
285 	"ParityTypeEven",
286 	"ParityTypeOdd",
287 	"ParityTypeMark",
288 	"ParityTypeSpace",
289 	"/* UNKNOWN parity keyword */",
290 	"/* UNKNOWN parity keyword */",
291 	"/* UNKNOWN parity keyword */"
292 };
293 
294 #endif
295 
296 /*
297  * Base sizes of the raw AML resource descriptors, indexed by resource type.
298  * Zero indicates a reserved (and therefore invalid) resource type.
299  */
300 const u8 acpi_gbl_resource_aml_sizes[] = {
301 	/* Small descriptors */
302 
303 	0,
304 	0,
305 	0,
306 	0,
307 	ACPI_AML_SIZE_SMALL(struct aml_resource_irq),
308 	ACPI_AML_SIZE_SMALL(struct aml_resource_dma),
309 	ACPI_AML_SIZE_SMALL(struct aml_resource_start_dependent),
310 	ACPI_AML_SIZE_SMALL(struct aml_resource_end_dependent),
311 	ACPI_AML_SIZE_SMALL(struct aml_resource_io),
312 	ACPI_AML_SIZE_SMALL(struct aml_resource_fixed_io),
313 	ACPI_AML_SIZE_SMALL(struct aml_resource_fixed_dma),
314 	0,
315 	0,
316 	0,
317 	ACPI_AML_SIZE_SMALL(struct aml_resource_vendor_small),
318 	ACPI_AML_SIZE_SMALL(struct aml_resource_end_tag),
319 
320 	/* Large descriptors */
321 
322 	0,
323 	ACPI_AML_SIZE_LARGE(struct aml_resource_memory24),
324 	ACPI_AML_SIZE_LARGE(struct aml_resource_generic_register),
325 	0,
326 	ACPI_AML_SIZE_LARGE(struct aml_resource_vendor_large),
327 	ACPI_AML_SIZE_LARGE(struct aml_resource_memory32),
328 	ACPI_AML_SIZE_LARGE(struct aml_resource_fixed_memory32),
329 	ACPI_AML_SIZE_LARGE(struct aml_resource_address32),
330 	ACPI_AML_SIZE_LARGE(struct aml_resource_address16),
331 	ACPI_AML_SIZE_LARGE(struct aml_resource_extended_irq),
332 	ACPI_AML_SIZE_LARGE(struct aml_resource_address64),
333 	ACPI_AML_SIZE_LARGE(struct aml_resource_extended_address64),
334 	ACPI_AML_SIZE_LARGE(struct aml_resource_gpio),
335 	0,
336 	ACPI_AML_SIZE_LARGE(struct aml_resource_common_serialbus),
337 };
338 
339 const u8 acpi_gbl_resource_aml_serial_bus_sizes[] = {
340 	0,
341 	ACPI_AML_SIZE_LARGE(struct aml_resource_i2c_serialbus),
342 	ACPI_AML_SIZE_LARGE(struct aml_resource_spi_serialbus),
343 	ACPI_AML_SIZE_LARGE(struct aml_resource_uart_serialbus),
344 };
345 
346 /*
347  * Resource types, used to validate the resource length field.
348  * The length of fixed-length types must match exactly, variable
349  * lengths must meet the minimum required length, etc.
350  * Zero indicates a reserved (and therefore invalid) resource type.
351  */
352 static const u8 acpi_gbl_resource_types[] = {
353 	/* Small descriptors */
354 
355 	0,
356 	0,
357 	0,
358 	0,
359 	ACPI_SMALL_VARIABLE_LENGTH,	/* 04 IRQ */
360 	ACPI_FIXED_LENGTH,	/* 05 DMA */
361 	ACPI_SMALL_VARIABLE_LENGTH,	/* 06 start_dependent_functions */
362 	ACPI_FIXED_LENGTH,	/* 07 end_dependent_functions */
363 	ACPI_FIXED_LENGTH,	/* 08 IO */
364 	ACPI_FIXED_LENGTH,	/* 09 fixed_IO */
365 	ACPI_FIXED_LENGTH,	/* 0A fixed_DMA */
366 	0,
367 	0,
368 	0,
369 	ACPI_VARIABLE_LENGTH,	/* 0E vendor_short */
370 	ACPI_FIXED_LENGTH,	/* 0F end_tag */
371 
372 	/* Large descriptors */
373 
374 	0,
375 	ACPI_FIXED_LENGTH,	/* 01 Memory24 */
376 	ACPI_FIXED_LENGTH,	/* 02 generic_register */
377 	0,
378 	ACPI_VARIABLE_LENGTH,	/* 04 vendor_long */
379 	ACPI_FIXED_LENGTH,	/* 05 Memory32 */
380 	ACPI_FIXED_LENGTH,	/* 06 memory32_fixed */
381 	ACPI_VARIABLE_LENGTH,	/* 07 Dword* address */
382 	ACPI_VARIABLE_LENGTH,	/* 08 Word* address */
383 	ACPI_VARIABLE_LENGTH,	/* 09 extended_IRQ */
384 	ACPI_VARIABLE_LENGTH,	/* 0A Qword* address */
385 	ACPI_FIXED_LENGTH,	/* 0B Extended* address */
386 	ACPI_VARIABLE_LENGTH,	/* 0C Gpio* */
387 	0,
388 	ACPI_VARIABLE_LENGTH	/* 0E *serial_bus */
389 };
390 
391 /*******************************************************************************
392  *
393  * FUNCTION:    acpi_ut_walk_aml_resources
394  *
395  * PARAMETERS:  walk_state          - Current walk info
396  * PARAMETERS:  aml                 - Pointer to the raw AML resource template
397  *              aml_length          - Length of the entire template
398  *              user_function       - Called once for each descriptor found. If
399  *                                    NULL, a pointer to the end_tag is returned
400  *              context             - Passed to user_function
401  *
402  * RETURN:      Status
403  *
404  * DESCRIPTION: Walk a raw AML resource list(buffer). User function called
405  *              once for each resource found.
406  *
407  ******************************************************************************/
408 
409 acpi_status
410 acpi_ut_walk_aml_resources(struct acpi_walk_state *walk_state,
411 			   u8 *aml,
412 			   acpi_size aml_length,
413 			   acpi_walk_aml_callback user_function, void **context)
414 {
415 	acpi_status status;
416 	u8 *end_aml;
417 	u8 resource_index;
418 	u32 length;
419 	u32 offset = 0;
420 	u8 end_tag[2] = { 0x79, 0x00 };
421 
422 	ACPI_FUNCTION_TRACE(ut_walk_aml_resources);
423 
424 	/* The absolute minimum resource template is one end_tag descriptor */
425 
426 	if (aml_length < sizeof(struct aml_resource_end_tag)) {
427 		return_ACPI_STATUS(AE_AML_NO_RESOURCE_END_TAG);
428 	}
429 
430 	/* Point to the end of the resource template buffer */
431 
432 	end_aml = aml + aml_length;
433 
434 	/* Walk the byte list, abort on any invalid descriptor type or length */
435 
436 	while (aml < end_aml) {
437 
438 		/* Validate the Resource Type and Resource Length */
439 
440 		status =
441 		    acpi_ut_validate_resource(walk_state, aml, &resource_index);
442 		if (ACPI_FAILURE(status)) {
443 			/*
444 			 * Exit on failure. Cannot continue because the descriptor length
445 			 * may be bogus also.
446 			 */
447 			return_ACPI_STATUS(status);
448 		}
449 
450 		/* Get the length of this descriptor */
451 
452 		length = acpi_ut_get_descriptor_length(aml);
453 
454 		/* Invoke the user function */
455 
456 		if (user_function) {
457 			status =
458 			    user_function(aml, length, offset, resource_index,
459 					  context);
460 			if (ACPI_FAILURE(status)) {
461 				return_ACPI_STATUS(status);
462 			}
463 		}
464 
465 		/* An end_tag descriptor terminates this resource template */
466 
467 		if (acpi_ut_get_resource_type(aml) ==
468 		    ACPI_RESOURCE_NAME_END_TAG) {
469 			/*
470 			 * There must be at least one more byte in the buffer for
471 			 * the 2nd byte of the end_tag
472 			 */
473 			if ((aml + 1) >= end_aml) {
474 				return_ACPI_STATUS(AE_AML_NO_RESOURCE_END_TAG);
475 			}
476 
477 			/* Return the pointer to the end_tag if requested */
478 
479 			if (!user_function) {
480 				*context = aml;
481 			}
482 
483 			/* Normal exit */
484 
485 			return_ACPI_STATUS(AE_OK);
486 		}
487 
488 		aml += length;
489 		offset += length;
490 	}
491 
492 	/* Did not find an end_tag descriptor */
493 
494 	if (user_function) {
495 
496 		/* Insert an end_tag anyway. acpi_rs_get_list_length always leaves room */
497 
498 		(void)acpi_ut_validate_resource(walk_state, end_tag,
499 						&resource_index);
500 		status =
501 		    user_function(end_tag, 2, offset, resource_index, context);
502 		if (ACPI_FAILURE(status)) {
503 			return_ACPI_STATUS(status);
504 		}
505 	}
506 
507 	return_ACPI_STATUS(AE_AML_NO_RESOURCE_END_TAG);
508 }
509 
510 /*******************************************************************************
511  *
512  * FUNCTION:    acpi_ut_validate_resource
513  *
514  * PARAMETERS:  walk_state          - Current walk info
515  *              aml                 - Pointer to the raw AML resource descriptor
516  *              return_index        - Where the resource index is returned. NULL
517  *                                    if the index is not required.
518  *
519  * RETURN:      Status, and optionally the Index into the global resource tables
520  *
521  * DESCRIPTION: Validate an AML resource descriptor by checking the Resource
522  *              Type and Resource Length. Returns an index into the global
523  *              resource information/dispatch tables for later use.
524  *
525  ******************************************************************************/
526 
527 acpi_status
528 acpi_ut_validate_resource(struct acpi_walk_state *walk_state,
529 			  void *aml, u8 *return_index)
530 {
531 	union aml_resource *aml_resource;
532 	u8 resource_type;
533 	u8 resource_index;
534 	acpi_rs_length resource_length;
535 	acpi_rs_length minimum_resource_length;
536 
537 	ACPI_FUNCTION_ENTRY();
538 
539 	/*
540 	 * 1) Validate the resource_type field (Byte 0)
541 	 */
542 	resource_type = ACPI_GET8(aml);
543 
544 	/*
545 	 * Byte 0 contains the descriptor name (Resource Type)
546 	 * Examine the large/small bit in the resource header
547 	 */
548 	if (resource_type & ACPI_RESOURCE_NAME_LARGE) {
549 
550 		/* Verify the large resource type (name) against the max */
551 
552 		if (resource_type > ACPI_RESOURCE_NAME_LARGE_MAX) {
553 			goto invalid_resource;
554 		}
555 
556 		/*
557 		 * Large Resource Type -- bits 6:0 contain the name
558 		 * Translate range 0x80-0x8B to index range 0x10-0x1B
559 		 */
560 		resource_index = (u8) (resource_type - 0x70);
561 	} else {
562 		/*
563 		 * Small Resource Type -- bits 6:3 contain the name
564 		 * Shift range to index range 0x00-0x0F
565 		 */
566 		resource_index = (u8)
567 		    ((resource_type & ACPI_RESOURCE_NAME_SMALL_MASK) >> 3);
568 	}
569 
570 	/*
571 	 * Check validity of the resource type, via acpi_gbl_resource_types. Zero
572 	 * indicates an invalid resource.
573 	 */
574 	if (!acpi_gbl_resource_types[resource_index]) {
575 		goto invalid_resource;
576 	}
577 
578 	/*
579 	 * Validate the resource_length field. This ensures that the length
580 	 * is at least reasonable, and guarantees that it is non-zero.
581 	 */
582 	resource_length = acpi_ut_get_resource_length(aml);
583 	minimum_resource_length = acpi_gbl_resource_aml_sizes[resource_index];
584 
585 	/* Validate based upon the type of resource - fixed length or variable */
586 
587 	switch (acpi_gbl_resource_types[resource_index]) {
588 	case ACPI_FIXED_LENGTH:
589 
590 		/* Fixed length resource, length must match exactly */
591 
592 		if (resource_length != minimum_resource_length) {
593 			goto bad_resource_length;
594 		}
595 		break;
596 
597 	case ACPI_VARIABLE_LENGTH:
598 
599 		/* Variable length resource, length must be at least the minimum */
600 
601 		if (resource_length < minimum_resource_length) {
602 			goto bad_resource_length;
603 		}
604 		break;
605 
606 	case ACPI_SMALL_VARIABLE_LENGTH:
607 
608 		/* Small variable length resource, length can be (Min) or (Min-1) */
609 
610 		if ((resource_length > minimum_resource_length) ||
611 		    (resource_length < (minimum_resource_length - 1))) {
612 			goto bad_resource_length;
613 		}
614 		break;
615 
616 	default:
617 
618 		/* Shouldn't happen (because of validation earlier), but be sure */
619 
620 		goto invalid_resource;
621 	}
622 
623 	aml_resource = ACPI_CAST_PTR(union aml_resource, aml);
624 	if (resource_type == ACPI_RESOURCE_NAME_SERIAL_BUS) {
625 
626 		/* Validate the bus_type field */
627 
628 		if ((aml_resource->common_serial_bus.type == 0) ||
629 		    (aml_resource->common_serial_bus.type >
630 		     AML_RESOURCE_MAX_SERIALBUSTYPE)) {
631 			if (walk_state) {
632 				ACPI_ERROR((AE_INFO,
633 					    "Invalid/unsupported SerialBus resource descriptor: BusType 0x%2.2X",
634 					    aml_resource->common_serial_bus.
635 					    type));
636 			}
637 			return (AE_AML_INVALID_RESOURCE_TYPE);
638 		}
639 	}
640 
641 	/* Optionally return the resource table index */
642 
643 	if (return_index) {
644 		*return_index = resource_index;
645 	}
646 
647 	return (AE_OK);
648 
649 invalid_resource:
650 
651 	if (walk_state) {
652 		ACPI_ERROR((AE_INFO,
653 			    "Invalid/unsupported resource descriptor: Type 0x%2.2X",
654 			    resource_type));
655 	}
656 	return (AE_AML_INVALID_RESOURCE_TYPE);
657 
658 bad_resource_length:
659 
660 	if (walk_state) {
661 		ACPI_ERROR((AE_INFO,
662 			    "Invalid resource descriptor length: Type "
663 			    "0x%2.2X, Length 0x%4.4X, MinLength 0x%4.4X",
664 			    resource_type, resource_length,
665 			    minimum_resource_length));
666 	}
667 	return (AE_AML_BAD_RESOURCE_LENGTH);
668 }
669 
670 /*******************************************************************************
671  *
672  * FUNCTION:    acpi_ut_get_resource_type
673  *
674  * PARAMETERS:  aml             - Pointer to the raw AML resource descriptor
675  *
676  * RETURN:      The Resource Type with no extraneous bits (except the
677  *              Large/Small descriptor bit -- this is left alone)
678  *
679  * DESCRIPTION: Extract the Resource Type/Name from the first byte of
680  *              a resource descriptor.
681  *
682  ******************************************************************************/
683 
684 u8 acpi_ut_get_resource_type(void *aml)
685 {
686 	ACPI_FUNCTION_ENTRY();
687 
688 	/*
689 	 * Byte 0 contains the descriptor name (Resource Type)
690 	 * Examine the large/small bit in the resource header
691 	 */
692 	if (ACPI_GET8(aml) & ACPI_RESOURCE_NAME_LARGE) {
693 
694 		/* Large Resource Type -- bits 6:0 contain the name */
695 
696 		return (ACPI_GET8(aml));
697 	} else {
698 		/* Small Resource Type -- bits 6:3 contain the name */
699 
700 		return ((u8) (ACPI_GET8(aml) & ACPI_RESOURCE_NAME_SMALL_MASK));
701 	}
702 }
703 
704 /*******************************************************************************
705  *
706  * FUNCTION:    acpi_ut_get_resource_length
707  *
708  * PARAMETERS:  aml             - Pointer to the raw AML resource descriptor
709  *
710  * RETURN:      Byte Length
711  *
712  * DESCRIPTION: Get the "Resource Length" of a raw AML descriptor. By
713  *              definition, this does not include the size of the descriptor
714  *              header or the length field itself.
715  *
716  ******************************************************************************/
717 
718 u16 acpi_ut_get_resource_length(void *aml)
719 {
720 	acpi_rs_length resource_length;
721 
722 	ACPI_FUNCTION_ENTRY();
723 
724 	/*
725 	 * Byte 0 contains the descriptor name (Resource Type)
726 	 * Examine the large/small bit in the resource header
727 	 */
728 	if (ACPI_GET8(aml) & ACPI_RESOURCE_NAME_LARGE) {
729 
730 		/* Large Resource type -- bytes 1-2 contain the 16-bit length */
731 
732 		ACPI_MOVE_16_TO_16(&resource_length, ACPI_ADD_PTR(u8, aml, 1));
733 
734 	} else {
735 		/* Small Resource type -- bits 2:0 of byte 0 contain the length */
736 
737 		resource_length = (u16) (ACPI_GET8(aml) &
738 					 ACPI_RESOURCE_NAME_SMALL_LENGTH_MASK);
739 	}
740 
741 	return (resource_length);
742 }
743 
744 /*******************************************************************************
745  *
746  * FUNCTION:    acpi_ut_get_resource_header_length
747  *
748  * PARAMETERS:  aml             - Pointer to the raw AML resource descriptor
749  *
750  * RETURN:      Length of the AML header (depends on large/small descriptor)
751  *
752  * DESCRIPTION: Get the length of the header for this resource.
753  *
754  ******************************************************************************/
755 
756 u8 acpi_ut_get_resource_header_length(void *aml)
757 {
758 	ACPI_FUNCTION_ENTRY();
759 
760 	/* Examine the large/small bit in the resource header */
761 
762 	if (ACPI_GET8(aml) & ACPI_RESOURCE_NAME_LARGE) {
763 		return (sizeof(struct aml_resource_large_header));
764 	} else {
765 		return (sizeof(struct aml_resource_small_header));
766 	}
767 }
768 
769 /*******************************************************************************
770  *
771  * FUNCTION:    acpi_ut_get_descriptor_length
772  *
773  * PARAMETERS:  aml             - Pointer to the raw AML resource descriptor
774  *
775  * RETURN:      Byte length
776  *
777  * DESCRIPTION: Get the total byte length of a raw AML descriptor, including the
778  *              length of the descriptor header and the length field itself.
779  *              Used to walk descriptor lists.
780  *
781  ******************************************************************************/
782 
783 u32 acpi_ut_get_descriptor_length(void *aml)
784 {
785 	ACPI_FUNCTION_ENTRY();
786 
787 	/*
788 	 * Get the Resource Length (does not include header length) and add
789 	 * the header length (depends on if this is a small or large resource)
790 	 */
791 	return (acpi_ut_get_resource_length(aml) +
792 		acpi_ut_get_resource_header_length(aml));
793 }
794 
795 /*******************************************************************************
796  *
797  * FUNCTION:    acpi_ut_get_resource_end_tag
798  *
799  * PARAMETERS:  obj_desc        - The resource template buffer object
800  *              end_tag         - Where the pointer to the end_tag is returned
801  *
802  * RETURN:      Status, pointer to the end tag
803  *
804  * DESCRIPTION: Find the end_tag resource descriptor in an AML resource template
805  *              Note: allows a buffer length of zero.
806  *
807  ******************************************************************************/
808 
809 acpi_status
810 acpi_ut_get_resource_end_tag(union acpi_operand_object *obj_desc, u8 **end_tag)
811 {
812 	acpi_status status;
813 
814 	ACPI_FUNCTION_TRACE(ut_get_resource_end_tag);
815 
816 	/* Allow a buffer length of zero */
817 
818 	if (!obj_desc->buffer.length) {
819 		*end_tag = obj_desc->buffer.pointer;
820 		return_ACPI_STATUS(AE_OK);
821 	}
822 
823 	/* Validate the template and get a pointer to the end_tag */
824 
825 	status = acpi_ut_walk_aml_resources(NULL, obj_desc->buffer.pointer,
826 					    obj_desc->buffer.length, NULL,
827 					    (void **)end_tag);
828 
829 	return_ACPI_STATUS(status);
830 }
831