xref: /openbmc/linux/drivers/acpi/acpica/utresrc.c (revision 95e9fd10)
1 /*******************************************************************************
2  *
3  * Module Name: utresrc - Resource management utilities
4  *
5  ******************************************************************************/
6 
7 /*
8  * Copyright (C) 2000 - 2012, Intel Corp.
9  * All rights reserved.
10  *
11  * Redistribution and use in source and binary forms, with or without
12  * modification, are permitted provided that the following conditions
13  * are met:
14  * 1. Redistributions of source code must retain the above copyright
15  *    notice, this list of conditions, and the following disclaimer,
16  *    without modification.
17  * 2. Redistributions in binary form must reproduce at minimum a disclaimer
18  *    substantially similar to the "NO WARRANTY" disclaimer below
19  *    ("Disclaimer") and any redistribution must be conditioned upon
20  *    including a substantially similar Disclaimer requirement for further
21  *    binary redistribution.
22  * 3. Neither the names of the above-listed copyright holders nor the names
23  *    of any contributors may be used to endorse or promote products derived
24  *    from this software without specific prior written permission.
25  *
26  * Alternatively, this software may be distributed under the terms of the
27  * GNU General Public License ("GPL") version 2 as published by the Free
28  * Software Foundation.
29  *
30  * NO WARRANTY
31  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
32  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
33  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
34  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
35  * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
36  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
37  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
38  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
39  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
40  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
41  * POSSIBILITY OF SUCH DAMAGES.
42  */
43 
44 #include <acpi/acpi.h>
45 #include "accommon.h"
46 #include "acresrc.h"
47 
48 #define _COMPONENT          ACPI_UTILITIES
49 ACPI_MODULE_NAME("utresrc")
50 #if defined(ACPI_DISASSEMBLER) || defined (ACPI_DEBUGGER)
51 /*
52  * Strings used to decode resource descriptors.
53  * Used by both the disassembler and the debugger resource dump routines
54  */
55 const char *acpi_gbl_bm_decode[] = {
56 	"NotBusMaster",
57 	"BusMaster"
58 };
59 
60 const char *acpi_gbl_config_decode[] = {
61 	"0 - Good Configuration",
62 	"1 - Acceptable Configuration",
63 	"2 - Suboptimal Configuration",
64 	"3 - ***Invalid Configuration***",
65 };
66 
67 const char *acpi_gbl_consume_decode[] = {
68 	"ResourceProducer",
69 	"ResourceConsumer"
70 };
71 
72 const char *acpi_gbl_dec_decode[] = {
73 	"PosDecode",
74 	"SubDecode"
75 };
76 
77 const char *acpi_gbl_he_decode[] = {
78 	"Level",
79 	"Edge"
80 };
81 
82 const char *acpi_gbl_io_decode[] = {
83 	"Decode10",
84 	"Decode16"
85 };
86 
87 const char *acpi_gbl_ll_decode[] = {
88 	"ActiveHigh",
89 	"ActiveLow"
90 };
91 
92 const char *acpi_gbl_max_decode[] = {
93 	"MaxNotFixed",
94 	"MaxFixed"
95 };
96 
97 const char *acpi_gbl_mem_decode[] = {
98 	"NonCacheable",
99 	"Cacheable",
100 	"WriteCombining",
101 	"Prefetchable"
102 };
103 
104 const char *acpi_gbl_min_decode[] = {
105 	"MinNotFixed",
106 	"MinFixed"
107 };
108 
109 const char *acpi_gbl_mtp_decode[] = {
110 	"AddressRangeMemory",
111 	"AddressRangeReserved",
112 	"AddressRangeACPI",
113 	"AddressRangeNVS"
114 };
115 
116 const char *acpi_gbl_rng_decode[] = {
117 	"InvalidRanges",
118 	"NonISAOnlyRanges",
119 	"ISAOnlyRanges",
120 	"EntireRange"
121 };
122 
123 const char *acpi_gbl_rw_decode[] = {
124 	"ReadOnly",
125 	"ReadWrite"
126 };
127 
128 const char *acpi_gbl_shr_decode[] = {
129 	"Exclusive",
130 	"Shared"
131 };
132 
133 const char *acpi_gbl_siz_decode[] = {
134 	"Transfer8",
135 	"Transfer8_16",
136 	"Transfer16",
137 	"InvalidSize"
138 };
139 
140 const char *acpi_gbl_trs_decode[] = {
141 	"DenseTranslation",
142 	"SparseTranslation"
143 };
144 
145 const char *acpi_gbl_ttp_decode[] = {
146 	"TypeStatic",
147 	"TypeTranslation"
148 };
149 
150 const char *acpi_gbl_typ_decode[] = {
151 	"Compatibility",
152 	"TypeA",
153 	"TypeB",
154 	"TypeF"
155 };
156 
157 const char *acpi_gbl_ppc_decode[] = {
158 	"PullDefault",
159 	"PullUp",
160 	"PullDown",
161 	"PullNone"
162 };
163 
164 const char *acpi_gbl_ior_decode[] = {
165 	"IoRestrictionNone",
166 	"IoRestrictionInputOnly",
167 	"IoRestrictionOutputOnly",
168 	"IoRestrictionNoneAndPreserve"
169 };
170 
171 const char *acpi_gbl_dts_decode[] = {
172 	"Width8bit",
173 	"Width16bit",
174 	"Width32bit",
175 	"Width64bit",
176 	"Width128bit",
177 	"Width256bit",
178 };
179 
180 /* GPIO connection type */
181 
182 const char *acpi_gbl_ct_decode[] = {
183 	"Interrupt",
184 	"I/O"
185 };
186 
187 /* Serial bus type */
188 
189 const char *acpi_gbl_sbt_decode[] = {
190 	"/* UNKNOWN serial bus type */",
191 	"I2C",
192 	"SPI",
193 	"UART"
194 };
195 
196 /* I2C serial bus access mode */
197 
198 const char *acpi_gbl_am_decode[] = {
199 	"AddressingMode7Bit",
200 	"AddressingMode10Bit"
201 };
202 
203 /* I2C serial bus slave mode */
204 
205 const char *acpi_gbl_sm_decode[] = {
206 	"ControllerInitiated",
207 	"DeviceInitiated"
208 };
209 
210 /* SPI serial bus wire mode */
211 
212 const char *acpi_gbl_wm_decode[] = {
213 	"FourWireMode",
214 	"ThreeWireMode"
215 };
216 
217 /* SPI serial clock phase */
218 
219 const char *acpi_gbl_cph_decode[] = {
220 	"ClockPhaseFirst",
221 	"ClockPhaseSecond"
222 };
223 
224 /* SPI serial bus clock polarity */
225 
226 const char *acpi_gbl_cpo_decode[] = {
227 	"ClockPolarityLow",
228 	"ClockPolarityHigh"
229 };
230 
231 /* SPI serial bus device polarity */
232 
233 const char *acpi_gbl_dp_decode[] = {
234 	"PolarityLow",
235 	"PolarityHigh"
236 };
237 
238 /* UART serial bus endian */
239 
240 const char *acpi_gbl_ed_decode[] = {
241 	"LittleEndian",
242 	"BigEndian"
243 };
244 
245 /* UART serial bus bits per byte */
246 
247 const char *acpi_gbl_bpb_decode[] = {
248 	"DataBitsFive",
249 	"DataBitsSix",
250 	"DataBitsSeven",
251 	"DataBitsEight",
252 	"DataBitsNine",
253 	"/* UNKNOWN Bits per byte */",
254 	"/* UNKNOWN Bits per byte */",
255 	"/* UNKNOWN Bits per byte */"
256 };
257 
258 /* UART serial bus stop bits */
259 
260 const char *acpi_gbl_sb_decode[] = {
261 	"StopBitsNone",
262 	"StopBitsOne",
263 	"StopBitsOnePlusHalf",
264 	"StopBitsTwo"
265 };
266 
267 /* UART serial bus flow control */
268 
269 const char *acpi_gbl_fc_decode[] = {
270 	"FlowControlNone",
271 	"FlowControlHardware",
272 	"FlowControlXON",
273 	"/* UNKNOWN flow control keyword */"
274 };
275 
276 /* UART serial bus parity type */
277 
278 const char *acpi_gbl_pt_decode[] = {
279 	"ParityTypeNone",
280 	"ParityTypeEven",
281 	"ParityTypeOdd",
282 	"ParityTypeMark",
283 	"ParityTypeSpace",
284 	"/* UNKNOWN parity keyword */",
285 	"/* UNKNOWN parity keyword */",
286 	"/* UNKNOWN parity keyword */"
287 };
288 
289 #endif
290 
291 /*
292  * Base sizes of the raw AML resource descriptors, indexed by resource type.
293  * Zero indicates a reserved (and therefore invalid) resource type.
294  */
295 const u8 acpi_gbl_resource_aml_sizes[] = {
296 	/* Small descriptors */
297 
298 	0,
299 	0,
300 	0,
301 	0,
302 	ACPI_AML_SIZE_SMALL(struct aml_resource_irq),
303 	ACPI_AML_SIZE_SMALL(struct aml_resource_dma),
304 	ACPI_AML_SIZE_SMALL(struct aml_resource_start_dependent),
305 	ACPI_AML_SIZE_SMALL(struct aml_resource_end_dependent),
306 	ACPI_AML_SIZE_SMALL(struct aml_resource_io),
307 	ACPI_AML_SIZE_SMALL(struct aml_resource_fixed_io),
308 	ACPI_AML_SIZE_SMALL(struct aml_resource_fixed_dma),
309 	0,
310 	0,
311 	0,
312 	ACPI_AML_SIZE_SMALL(struct aml_resource_vendor_small),
313 	ACPI_AML_SIZE_SMALL(struct aml_resource_end_tag),
314 
315 	/* Large descriptors */
316 
317 	0,
318 	ACPI_AML_SIZE_LARGE(struct aml_resource_memory24),
319 	ACPI_AML_SIZE_LARGE(struct aml_resource_generic_register),
320 	0,
321 	ACPI_AML_SIZE_LARGE(struct aml_resource_vendor_large),
322 	ACPI_AML_SIZE_LARGE(struct aml_resource_memory32),
323 	ACPI_AML_SIZE_LARGE(struct aml_resource_fixed_memory32),
324 	ACPI_AML_SIZE_LARGE(struct aml_resource_address32),
325 	ACPI_AML_SIZE_LARGE(struct aml_resource_address16),
326 	ACPI_AML_SIZE_LARGE(struct aml_resource_extended_irq),
327 	ACPI_AML_SIZE_LARGE(struct aml_resource_address64),
328 	ACPI_AML_SIZE_LARGE(struct aml_resource_extended_address64),
329 	ACPI_AML_SIZE_LARGE(struct aml_resource_gpio),
330 	0,
331 	ACPI_AML_SIZE_LARGE(struct aml_resource_common_serialbus),
332 };
333 
334 const u8 acpi_gbl_resource_aml_serial_bus_sizes[] = {
335 	0,
336 	ACPI_AML_SIZE_LARGE(struct aml_resource_i2c_serialbus),
337 	ACPI_AML_SIZE_LARGE(struct aml_resource_spi_serialbus),
338 	ACPI_AML_SIZE_LARGE(struct aml_resource_uart_serialbus),
339 };
340 
341 /*
342  * Resource types, used to validate the resource length field.
343  * The length of fixed-length types must match exactly, variable
344  * lengths must meet the minimum required length, etc.
345  * Zero indicates a reserved (and therefore invalid) resource type.
346  */
347 static const u8 acpi_gbl_resource_types[] = {
348 	/* Small descriptors */
349 
350 	0,
351 	0,
352 	0,
353 	0,
354 	ACPI_SMALL_VARIABLE_LENGTH,	/* 04 IRQ */
355 	ACPI_FIXED_LENGTH,	/* 05 DMA */
356 	ACPI_SMALL_VARIABLE_LENGTH,	/* 06 start_dependent_functions */
357 	ACPI_FIXED_LENGTH,	/* 07 end_dependent_functions */
358 	ACPI_FIXED_LENGTH,	/* 08 IO */
359 	ACPI_FIXED_LENGTH,	/* 09 fixed_IO */
360 	ACPI_FIXED_LENGTH,	/* 0A fixed_DMA */
361 	0,
362 	0,
363 	0,
364 	ACPI_VARIABLE_LENGTH,	/* 0E vendor_short */
365 	ACPI_FIXED_LENGTH,	/* 0F end_tag */
366 
367 	/* Large descriptors */
368 
369 	0,
370 	ACPI_FIXED_LENGTH,	/* 01 Memory24 */
371 	ACPI_FIXED_LENGTH,	/* 02 generic_register */
372 	0,
373 	ACPI_VARIABLE_LENGTH,	/* 04 vendor_long */
374 	ACPI_FIXED_LENGTH,	/* 05 Memory32 */
375 	ACPI_FIXED_LENGTH,	/* 06 memory32_fixed */
376 	ACPI_VARIABLE_LENGTH,	/* 07 Dword* address */
377 	ACPI_VARIABLE_LENGTH,	/* 08 Word* address */
378 	ACPI_VARIABLE_LENGTH,	/* 09 extended_IRQ */
379 	ACPI_VARIABLE_LENGTH,	/* 0A Qword* address */
380 	ACPI_FIXED_LENGTH,	/* 0B Extended* address */
381 	ACPI_VARIABLE_LENGTH,	/* 0C Gpio* */
382 	0,
383 	ACPI_VARIABLE_LENGTH	/* 0E *serial_bus */
384 };
385 
386 /*
387  * For the iASL compiler/disassembler, we don't want any error messages
388  * because the disassembler uses the resource validation code to determine
389  * if Buffer objects are actually Resource Templates.
390  */
391 #ifdef ACPI_ASL_COMPILER
392 #define ACPI_RESOURCE_ERROR(plist)
393 #else
394 #define ACPI_RESOURCE_ERROR(plist)  ACPI_ERROR(plist)
395 #endif
396 
397 /*******************************************************************************
398  *
399  * FUNCTION:    acpi_ut_walk_aml_resources
400  *
401  * PARAMETERS:  aml             - Pointer to the raw AML resource template
402  *              aml_length      - Length of the entire template
403  *              user_function   - Called once for each descriptor found. If
404  *                                NULL, a pointer to the end_tag is returned
405  *              context         - Passed to user_function
406  *
407  * RETURN:      Status
408  *
409  * DESCRIPTION: Walk a raw AML resource list(buffer). User function called
410  *              once for each resource found.
411  *
412  ******************************************************************************/
413 
414 acpi_status
415 acpi_ut_walk_aml_resources(u8 * aml,
416 			   acpi_size aml_length,
417 			   acpi_walk_aml_callback user_function, void **context)
418 {
419 	acpi_status status;
420 	u8 *end_aml;
421 	u8 resource_index;
422 	u32 length;
423 	u32 offset = 0;
424 	u8 end_tag[2] = { 0x79, 0x00 };
425 
426 	ACPI_FUNCTION_TRACE(ut_walk_aml_resources);
427 
428 	/* The absolute minimum resource template is one end_tag descriptor */
429 
430 	if (aml_length < sizeof(struct aml_resource_end_tag)) {
431 		return_ACPI_STATUS(AE_AML_NO_RESOURCE_END_TAG);
432 	}
433 
434 	/* Point to the end of the resource template buffer */
435 
436 	end_aml = aml + aml_length;
437 
438 	/* Walk the byte list, abort on any invalid descriptor type or length */
439 
440 	while (aml < end_aml) {
441 
442 		/* Validate the Resource Type and Resource Length */
443 
444 		status = acpi_ut_validate_resource(aml, &resource_index);
445 		if (ACPI_FAILURE(status)) {
446 			/*
447 			 * Exit on failure. Cannot continue because the descriptor length
448 			 * may be bogus also.
449 			 */
450 			return_ACPI_STATUS(status);
451 		}
452 
453 		/* Get the length of this descriptor */
454 
455 		length = acpi_ut_get_descriptor_length(aml);
456 
457 		/* Invoke the user function */
458 
459 		if (user_function) {
460 			status =
461 			    user_function(aml, length, offset, resource_index,
462 					  context);
463 			if (ACPI_FAILURE(status)) {
464 				return_ACPI_STATUS(status);
465 			}
466 		}
467 
468 		/* An end_tag descriptor terminates this resource template */
469 
470 		if (acpi_ut_get_resource_type(aml) ==
471 		    ACPI_RESOURCE_NAME_END_TAG) {
472 			/*
473 			 * There must be at least one more byte in the buffer for
474 			 * the 2nd byte of the end_tag
475 			 */
476 			if ((aml + 1) >= end_aml) {
477 				return_ACPI_STATUS(AE_AML_NO_RESOURCE_END_TAG);
478 			}
479 
480 			/* Return the pointer to the end_tag if requested */
481 
482 			if (!user_function) {
483 				*context = aml;
484 			}
485 
486 			/* Normal exit */
487 
488 			return_ACPI_STATUS(AE_OK);
489 		}
490 
491 		aml += length;
492 		offset += length;
493 	}
494 
495 	/* Did not find an end_tag descriptor */
496 
497 	if (user_function) {
498 
499 		/* Insert an end_tag anyway. acpi_rs_get_list_length always leaves room */
500 
501 		(void)acpi_ut_validate_resource(end_tag, &resource_index);
502 		status =
503 		    user_function(end_tag, 2, offset, resource_index, context);
504 		if (ACPI_FAILURE(status)) {
505 			return_ACPI_STATUS(status);
506 		}
507 	}
508 
509 	return_ACPI_STATUS(AE_AML_NO_RESOURCE_END_TAG);
510 }
511 
512 /*******************************************************************************
513  *
514  * FUNCTION:    acpi_ut_validate_resource
515  *
516  * PARAMETERS:  aml             - Pointer to the raw AML resource descriptor
517  *              return_index    - Where the resource index is returned. NULL
518  *                                if the index is not required.
519  *
520  * RETURN:      Status, and optionally the Index into the global resource tables
521  *
522  * DESCRIPTION: Validate an AML resource descriptor by checking the Resource
523  *              Type and Resource Length. Returns an index into the global
524  *              resource information/dispatch tables for later use.
525  *
526  ******************************************************************************/
527 
528 acpi_status acpi_ut_validate_resource(void *aml, u8 * return_index)
529 {
530 	union aml_resource *aml_resource;
531 	u8 resource_type;
532 	u8 resource_index;
533 	acpi_rs_length resource_length;
534 	acpi_rs_length minimum_resource_length;
535 
536 	ACPI_FUNCTION_ENTRY();
537 
538 	/*
539 	 * 1) Validate the resource_type field (Byte 0)
540 	 */
541 	resource_type = ACPI_GET8(aml);
542 
543 	/*
544 	 * Byte 0 contains the descriptor name (Resource Type)
545 	 * Examine the large/small bit in the resource header
546 	 */
547 	if (resource_type & ACPI_RESOURCE_NAME_LARGE) {
548 
549 		/* Verify the large resource type (name) against the max */
550 
551 		if (resource_type > ACPI_RESOURCE_NAME_LARGE_MAX) {
552 			goto invalid_resource;
553 		}
554 
555 		/*
556 		 * Large Resource Type -- bits 6:0 contain the name
557 		 * Translate range 0x80-0x8B to index range 0x10-0x1B
558 		 */
559 		resource_index = (u8) (resource_type - 0x70);
560 	} else {
561 		/*
562 		 * Small Resource Type -- bits 6:3 contain the name
563 		 * Shift range to index range 0x00-0x0F
564 		 */
565 		resource_index = (u8)
566 		    ((resource_type & ACPI_RESOURCE_NAME_SMALL_MASK) >> 3);
567 	}
568 
569 	/*
570 	 * Check validity of the resource type, via acpi_gbl_resource_types. Zero
571 	 * indicates an invalid resource.
572 	 */
573 	if (!acpi_gbl_resource_types[resource_index]) {
574 		goto invalid_resource;
575 	}
576 
577 	/*
578 	 * Validate the resource_length field. This ensures that the length
579 	 * is at least reasonable, and guarantees that it is non-zero.
580 	 */
581 	resource_length = acpi_ut_get_resource_length(aml);
582 	minimum_resource_length = acpi_gbl_resource_aml_sizes[resource_index];
583 
584 	/* Validate based upon the type of resource - fixed length or variable */
585 
586 	switch (acpi_gbl_resource_types[resource_index]) {
587 	case ACPI_FIXED_LENGTH:
588 
589 		/* Fixed length resource, length must match exactly */
590 
591 		if (resource_length != minimum_resource_length) {
592 			goto bad_resource_length;
593 		}
594 		break;
595 
596 	case ACPI_VARIABLE_LENGTH:
597 
598 		/* Variable length resource, length must be at least the minimum */
599 
600 		if (resource_length < minimum_resource_length) {
601 			goto bad_resource_length;
602 		}
603 		break;
604 
605 	case ACPI_SMALL_VARIABLE_LENGTH:
606 
607 		/* Small variable length resource, length can be (Min) or (Min-1) */
608 
609 		if ((resource_length > minimum_resource_length) ||
610 		    (resource_length < (minimum_resource_length - 1))) {
611 			goto bad_resource_length;
612 		}
613 		break;
614 
615 	default:
616 
617 		/* Shouldn't happen (because of validation earlier), but be sure */
618 
619 		goto invalid_resource;
620 	}
621 
622 	aml_resource = ACPI_CAST_PTR(union aml_resource, aml);
623 	if (resource_type == ACPI_RESOURCE_NAME_SERIAL_BUS) {
624 
625 		/* Validate the bus_type field */
626 
627 		if ((aml_resource->common_serial_bus.type == 0) ||
628 		    (aml_resource->common_serial_bus.type >
629 		     AML_RESOURCE_MAX_SERIALBUSTYPE)) {
630 			ACPI_RESOURCE_ERROR((AE_INFO,
631 					     "Invalid/unsupported SerialBus resource descriptor: BusType 0x%2.2X",
632 					     aml_resource->common_serial_bus.
633 					     type));
634 			return (AE_AML_INVALID_RESOURCE_TYPE);
635 		}
636 	}
637 
638 	/* Optionally return the resource table index */
639 
640 	if (return_index) {
641 		*return_index = resource_index;
642 	}
643 
644 	return (AE_OK);
645 
646       invalid_resource:
647 
648 	ACPI_RESOURCE_ERROR((AE_INFO,
649 			     "Invalid/unsupported resource descriptor: Type 0x%2.2X",
650 			     resource_type));
651 	return (AE_AML_INVALID_RESOURCE_TYPE);
652 
653       bad_resource_length:
654 
655 	ACPI_RESOURCE_ERROR((AE_INFO,
656 			     "Invalid resource descriptor length: Type "
657 			     "0x%2.2X, Length 0x%4.4X, MinLength 0x%4.4X",
658 			     resource_type, resource_length,
659 			     minimum_resource_length));
660 	return (AE_AML_BAD_RESOURCE_LENGTH);
661 }
662 
663 /*******************************************************************************
664  *
665  * FUNCTION:    acpi_ut_get_resource_type
666  *
667  * PARAMETERS:  aml             - Pointer to the raw AML resource descriptor
668  *
669  * RETURN:      The Resource Type with no extraneous bits (except the
670  *              Large/Small descriptor bit -- this is left alone)
671  *
672  * DESCRIPTION: Extract the Resource Type/Name from the first byte of
673  *              a resource descriptor.
674  *
675  ******************************************************************************/
676 
677 u8 acpi_ut_get_resource_type(void *aml)
678 {
679 	ACPI_FUNCTION_ENTRY();
680 
681 	/*
682 	 * Byte 0 contains the descriptor name (Resource Type)
683 	 * Examine the large/small bit in the resource header
684 	 */
685 	if (ACPI_GET8(aml) & ACPI_RESOURCE_NAME_LARGE) {
686 
687 		/* Large Resource Type -- bits 6:0 contain the name */
688 
689 		return (ACPI_GET8(aml));
690 	} else {
691 		/* Small Resource Type -- bits 6:3 contain the name */
692 
693 		return ((u8) (ACPI_GET8(aml) & ACPI_RESOURCE_NAME_SMALL_MASK));
694 	}
695 }
696 
697 /*******************************************************************************
698  *
699  * FUNCTION:    acpi_ut_get_resource_length
700  *
701  * PARAMETERS:  aml             - Pointer to the raw AML resource descriptor
702  *
703  * RETURN:      Byte Length
704  *
705  * DESCRIPTION: Get the "Resource Length" of a raw AML descriptor. By
706  *              definition, this does not include the size of the descriptor
707  *              header or the length field itself.
708  *
709  ******************************************************************************/
710 
711 u16 acpi_ut_get_resource_length(void *aml)
712 {
713 	acpi_rs_length resource_length;
714 
715 	ACPI_FUNCTION_ENTRY();
716 
717 	/*
718 	 * Byte 0 contains the descriptor name (Resource Type)
719 	 * Examine the large/small bit in the resource header
720 	 */
721 	if (ACPI_GET8(aml) & ACPI_RESOURCE_NAME_LARGE) {
722 
723 		/* Large Resource type -- bytes 1-2 contain the 16-bit length */
724 
725 		ACPI_MOVE_16_TO_16(&resource_length, ACPI_ADD_PTR(u8, aml, 1));
726 
727 	} else {
728 		/* Small Resource type -- bits 2:0 of byte 0 contain the length */
729 
730 		resource_length = (u16) (ACPI_GET8(aml) &
731 					 ACPI_RESOURCE_NAME_SMALL_LENGTH_MASK);
732 	}
733 
734 	return (resource_length);
735 }
736 
737 /*******************************************************************************
738  *
739  * FUNCTION:    acpi_ut_get_resource_header_length
740  *
741  * PARAMETERS:  aml             - Pointer to the raw AML resource descriptor
742  *
743  * RETURN:      Length of the AML header (depends on large/small descriptor)
744  *
745  * DESCRIPTION: Get the length of the header for this resource.
746  *
747  ******************************************************************************/
748 
749 u8 acpi_ut_get_resource_header_length(void *aml)
750 {
751 	ACPI_FUNCTION_ENTRY();
752 
753 	/* Examine the large/small bit in the resource header */
754 
755 	if (ACPI_GET8(aml) & ACPI_RESOURCE_NAME_LARGE) {
756 		return (sizeof(struct aml_resource_large_header));
757 	} else {
758 		return (sizeof(struct aml_resource_small_header));
759 	}
760 }
761 
762 /*******************************************************************************
763  *
764  * FUNCTION:    acpi_ut_get_descriptor_length
765  *
766  * PARAMETERS:  aml             - Pointer to the raw AML resource descriptor
767  *
768  * RETURN:      Byte length
769  *
770  * DESCRIPTION: Get the total byte length of a raw AML descriptor, including the
771  *              length of the descriptor header and the length field itself.
772  *              Used to walk descriptor lists.
773  *
774  ******************************************************************************/
775 
776 u32 acpi_ut_get_descriptor_length(void *aml)
777 {
778 	ACPI_FUNCTION_ENTRY();
779 
780 	/*
781 	 * Get the Resource Length (does not include header length) and add
782 	 * the header length (depends on if this is a small or large resource)
783 	 */
784 	return (acpi_ut_get_resource_length(aml) +
785 		acpi_ut_get_resource_header_length(aml));
786 }
787 
788 /*******************************************************************************
789  *
790  * FUNCTION:    acpi_ut_get_resource_end_tag
791  *
792  * PARAMETERS:  obj_desc        - The resource template buffer object
793  *              end_tag         - Where the pointer to the end_tag is returned
794  *
795  * RETURN:      Status, pointer to the end tag
796  *
797  * DESCRIPTION: Find the end_tag resource descriptor in an AML resource template
798  *              Note: allows a buffer length of zero.
799  *
800  ******************************************************************************/
801 
802 acpi_status
803 acpi_ut_get_resource_end_tag(union acpi_operand_object * obj_desc,
804 			     u8 ** end_tag)
805 {
806 	acpi_status status;
807 
808 	ACPI_FUNCTION_TRACE(ut_get_resource_end_tag);
809 
810 	/* Allow a buffer length of zero */
811 
812 	if (!obj_desc->buffer.length) {
813 		*end_tag = obj_desc->buffer.pointer;
814 		return_ACPI_STATUS(AE_OK);
815 	}
816 
817 	/* Validate the template and get a pointer to the end_tag */
818 
819 	status = acpi_ut_walk_aml_resources(obj_desc->buffer.pointer,
820 					    obj_desc->buffer.length, NULL,
821 					    (void **)end_tag);
822 
823 	return_ACPI_STATUS(status);
824 }
825