xref: /openbmc/linux/drivers/acpi/acpica/tbfadt.c (revision 37be287c)
1 /******************************************************************************
2  *
3  * Module Name: tbfadt   - FADT table utilities
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 "actables.h"
47 
48 #define _COMPONENT          ACPI_TABLES
49 ACPI_MODULE_NAME("tbfadt")
50 
51 /* Local prototypes */
52 static void
53 acpi_tb_init_generic_address(struct acpi_generic_address *generic_address,
54 			     u8 space_id,
55 			     u8 byte_width, u64 address, char *register_name);
56 
57 static void acpi_tb_convert_fadt(void);
58 
59 static void acpi_tb_setup_fadt_registers(void);
60 
61 static u64
62 acpi_tb_select_address(char *register_name, u32 address32, u64 address64);
63 
64 /* Table for conversion of FADT to common internal format and FADT validation */
65 
66 typedef struct acpi_fadt_info {
67 	char *name;
68 	u16 address64;
69 	u16 address32;
70 	u16 length;
71 	u8 default_length;
72 	u8 type;
73 
74 } acpi_fadt_info;
75 
76 #define ACPI_FADT_OPTIONAL          0
77 #define ACPI_FADT_REQUIRED          1
78 #define ACPI_FADT_SEPARATE_LENGTH   2
79 
80 static struct acpi_fadt_info fadt_info_table[] = {
81 	{"Pm1aEventBlock",
82 	 ACPI_FADT_OFFSET(xpm1a_event_block),
83 	 ACPI_FADT_OFFSET(pm1a_event_block),
84 	 ACPI_FADT_OFFSET(pm1_event_length),
85 	 ACPI_PM1_REGISTER_WIDTH * 2,	/* Enable + Status register */
86 	 ACPI_FADT_REQUIRED},
87 
88 	{"Pm1bEventBlock",
89 	 ACPI_FADT_OFFSET(xpm1b_event_block),
90 	 ACPI_FADT_OFFSET(pm1b_event_block),
91 	 ACPI_FADT_OFFSET(pm1_event_length),
92 	 ACPI_PM1_REGISTER_WIDTH * 2,	/* Enable + Status register */
93 	 ACPI_FADT_OPTIONAL},
94 
95 	{"Pm1aControlBlock",
96 	 ACPI_FADT_OFFSET(xpm1a_control_block),
97 	 ACPI_FADT_OFFSET(pm1a_control_block),
98 	 ACPI_FADT_OFFSET(pm1_control_length),
99 	 ACPI_PM1_REGISTER_WIDTH,
100 	 ACPI_FADT_REQUIRED},
101 
102 	{"Pm1bControlBlock",
103 	 ACPI_FADT_OFFSET(xpm1b_control_block),
104 	 ACPI_FADT_OFFSET(pm1b_control_block),
105 	 ACPI_FADT_OFFSET(pm1_control_length),
106 	 ACPI_PM1_REGISTER_WIDTH,
107 	 ACPI_FADT_OPTIONAL},
108 
109 	{"Pm2ControlBlock",
110 	 ACPI_FADT_OFFSET(xpm2_control_block),
111 	 ACPI_FADT_OFFSET(pm2_control_block),
112 	 ACPI_FADT_OFFSET(pm2_control_length),
113 	 ACPI_PM2_REGISTER_WIDTH,
114 	 ACPI_FADT_SEPARATE_LENGTH},
115 
116 	{"PmTimerBlock",
117 	 ACPI_FADT_OFFSET(xpm_timer_block),
118 	 ACPI_FADT_OFFSET(pm_timer_block),
119 	 ACPI_FADT_OFFSET(pm_timer_length),
120 	 ACPI_PM_TIMER_WIDTH,
121 	 ACPI_FADT_SEPARATE_LENGTH},	/* ACPI 5.0A: Timer is optional */
122 
123 	{"Gpe0Block",
124 	 ACPI_FADT_OFFSET(xgpe0_block),
125 	 ACPI_FADT_OFFSET(gpe0_block),
126 	 ACPI_FADT_OFFSET(gpe0_block_length),
127 	 0,
128 	 ACPI_FADT_SEPARATE_LENGTH},
129 
130 	{"Gpe1Block",
131 	 ACPI_FADT_OFFSET(xgpe1_block),
132 	 ACPI_FADT_OFFSET(gpe1_block),
133 	 ACPI_FADT_OFFSET(gpe1_block_length),
134 	 0,
135 	 ACPI_FADT_SEPARATE_LENGTH}
136 };
137 
138 #define ACPI_FADT_INFO_ENTRIES \
139 			(sizeof (fadt_info_table) / sizeof (struct acpi_fadt_info))
140 
141 /* Table used to split Event Blocks into separate status/enable registers */
142 
143 typedef struct acpi_fadt_pm_info {
144 	struct acpi_generic_address *target;
145 	u16 source;
146 	u8 register_num;
147 
148 } acpi_fadt_pm_info;
149 
150 static struct acpi_fadt_pm_info fadt_pm_info_table[] = {
151 	{&acpi_gbl_xpm1a_status,
152 	 ACPI_FADT_OFFSET(xpm1a_event_block),
153 	 0},
154 
155 	{&acpi_gbl_xpm1a_enable,
156 	 ACPI_FADT_OFFSET(xpm1a_event_block),
157 	 1},
158 
159 	{&acpi_gbl_xpm1b_status,
160 	 ACPI_FADT_OFFSET(xpm1b_event_block),
161 	 0},
162 
163 	{&acpi_gbl_xpm1b_enable,
164 	 ACPI_FADT_OFFSET(xpm1b_event_block),
165 	 1}
166 };
167 
168 #define ACPI_FADT_PM_INFO_ENTRIES \
169 			(sizeof (fadt_pm_info_table) / sizeof (struct acpi_fadt_pm_info))
170 
171 /*******************************************************************************
172  *
173  * FUNCTION:    acpi_tb_init_generic_address
174  *
175  * PARAMETERS:  generic_address     - GAS struct to be initialized
176  *              space_id            - ACPI Space ID for this register
177  *              byte_width          - Width of this register
178  *              address             - Address of the register
179  *              register_name       - ASCII name of the ACPI register
180  *
181  * RETURN:      None
182  *
183  * DESCRIPTION: Initialize a Generic Address Structure (GAS)
184  *              See the ACPI specification for a full description and
185  *              definition of this structure.
186  *
187  ******************************************************************************/
188 
189 static void
190 acpi_tb_init_generic_address(struct acpi_generic_address *generic_address,
191 			     u8 space_id,
192 			     u8 byte_width, u64 address, char *register_name)
193 {
194 	u8 bit_width;
195 
196 	/* Bit width field in the GAS is only one byte long, 255 max */
197 
198 	bit_width = (u8)(byte_width * 8);
199 
200 	if (byte_width > 31) {	/* (31*8)=248 */
201 		ACPI_ERROR((AE_INFO,
202 			    "%s - 32-bit FADT register is too long (%u bytes, %u bits) "
203 			    "to convert to GAS struct - 255 bits max, truncating",
204 			    register_name, byte_width, (byte_width * 8)));
205 
206 		bit_width = 255;
207 	}
208 
209 	/*
210 	 * The 64-bit Address field is non-aligned in the byte packed
211 	 * GAS struct.
212 	 */
213 	ACPI_MOVE_64_TO_64(&generic_address->address, &address);
214 
215 	/* All other fields are byte-wide */
216 
217 	generic_address->space_id = space_id;
218 	generic_address->bit_width = bit_width;
219 	generic_address->bit_offset = 0;
220 	generic_address->access_width = 0;	/* Access width ANY */
221 }
222 
223 /*******************************************************************************
224  *
225  * FUNCTION:    acpi_tb_select_address
226  *
227  * PARAMETERS:  register_name       - ASCII name of the ACPI register
228  *              address32           - 32-bit address of the register
229  *              address64           - 64-bit address of the register
230  *
231  * RETURN:      The resolved 64-bit address
232  *
233  * DESCRIPTION: Select between 32-bit and 64-bit versions of addresses within
234  *              the FADT. Used for the FACS and DSDT addresses.
235  *
236  * NOTES:
237  *
238  * Check for FACS and DSDT address mismatches. An address mismatch between
239  * the 32-bit and 64-bit address fields (FIRMWARE_CTRL/X_FIRMWARE_CTRL and
240  * DSDT/X_DSDT) could be a corrupted address field or it might indicate
241  * the presence of two FACS or two DSDT tables.
242  *
243  * November 2013:
244  * By default, as per the ACPICA specification, a valid 64-bit address is
245  * used regardless of the value of the 32-bit address. However, this
246  * behavior can be overridden via the acpi_gbl_use32_bit_fadt_addresses flag.
247  *
248  ******************************************************************************/
249 
250 static u64
251 acpi_tb_select_address(char *register_name, u32 address32, u64 address64)
252 {
253 
254 	if (!address64) {
255 
256 		/* 64-bit address is zero, use 32-bit address */
257 
258 		return ((u64)address32);
259 	}
260 
261 	if (address32 && (address64 != (u64)address32)) {
262 
263 		/* Address mismatch between 32-bit and 64-bit versions */
264 
265 		ACPI_BIOS_WARNING((AE_INFO,
266 				   "32/64X %s address mismatch in FADT: "
267 				   "0x%8.8X/0x%8.8X%8.8X, using %u-bit address",
268 				   register_name, address32,
269 				   ACPI_FORMAT_UINT64(address64),
270 				   acpi_gbl_use32_bit_fadt_addresses ? 32 :
271 				   64));
272 
273 		/* 32-bit address override */
274 
275 		if (acpi_gbl_use32_bit_fadt_addresses) {
276 			return ((u64)address32);
277 		}
278 	}
279 
280 	/* Default is to use the 64-bit address */
281 
282 	return (address64);
283 }
284 
285 /*******************************************************************************
286  *
287  * FUNCTION:    acpi_tb_parse_fadt
288  *
289  * PARAMETERS:  table_index         - Index for the FADT
290  *
291  * RETURN:      None
292  *
293  * DESCRIPTION: Initialize the FADT, DSDT and FACS tables
294  *              (FADT contains the addresses of the DSDT and FACS)
295  *
296  ******************************************************************************/
297 
298 void acpi_tb_parse_fadt(u32 table_index)
299 {
300 	u32 length;
301 	struct acpi_table_header *table;
302 
303 	/*
304 	 * The FADT has multiple versions with different lengths,
305 	 * and it contains pointers to both the DSDT and FACS tables.
306 	 *
307 	 * Get a local copy of the FADT and convert it to a common format
308 	 * Map entire FADT, assumed to be smaller than one page.
309 	 */
310 	length = acpi_gbl_root_table_list.tables[table_index].length;
311 
312 	table =
313 	    acpi_os_map_memory(acpi_gbl_root_table_list.tables[table_index].
314 			       address, length);
315 	if (!table) {
316 		return;
317 	}
318 
319 	/*
320 	 * Validate the FADT checksum before we copy the table. Ignore
321 	 * checksum error as we want to try to get the DSDT and FACS.
322 	 */
323 	(void)acpi_tb_verify_checksum(table, length);
324 
325 	/* Create a local copy of the FADT in common ACPI 2.0+ format */
326 
327 	acpi_tb_create_local_fadt(table, length);
328 
329 	/* All done with the real FADT, unmap it */
330 
331 	acpi_os_unmap_memory(table, length);
332 
333 	/* Obtain the DSDT and FACS tables via their addresses within the FADT */
334 
335 	acpi_tb_install_table((acpi_physical_address) acpi_gbl_FADT.Xdsdt,
336 			      ACPI_SIG_DSDT, ACPI_TABLE_INDEX_DSDT);
337 
338 	/* If Hardware Reduced flag is set, there is no FACS */
339 
340 	if (!acpi_gbl_reduced_hardware) {
341 		acpi_tb_install_table((acpi_physical_address) acpi_gbl_FADT.
342 				      Xfacs, ACPI_SIG_FACS,
343 				      ACPI_TABLE_INDEX_FACS);
344 	}
345 }
346 
347 /*******************************************************************************
348  *
349  * FUNCTION:    acpi_tb_create_local_fadt
350  *
351  * PARAMETERS:  table               - Pointer to BIOS FADT
352  *              length              - Length of the table
353  *
354  * RETURN:      None
355  *
356  * DESCRIPTION: Get a local copy of the FADT and convert it to a common format.
357  *              Performs validation on some important FADT fields.
358  *
359  * NOTE:        We create a local copy of the FADT regardless of the version.
360  *
361  ******************************************************************************/
362 
363 void acpi_tb_create_local_fadt(struct acpi_table_header *table, u32 length)
364 {
365 	/*
366 	 * Check if the FADT is larger than the largest table that we expect
367 	 * (the ACPI 5.0 version). If so, truncate the table, and issue
368 	 * a warning.
369 	 */
370 	if (length > sizeof(struct acpi_table_fadt)) {
371 		ACPI_BIOS_WARNING((AE_INFO,
372 				   "FADT (revision %u) is longer than ACPI 5.0 version, "
373 				   "truncating length %u to %u",
374 				   table->revision, length,
375 				   (u32)sizeof(struct acpi_table_fadt)));
376 	}
377 
378 	/* Clear the entire local FADT */
379 
380 	ACPI_MEMSET(&acpi_gbl_FADT, 0, sizeof(struct acpi_table_fadt));
381 
382 	/* Copy the original FADT, up to sizeof (struct acpi_table_fadt) */
383 
384 	ACPI_MEMCPY(&acpi_gbl_FADT, table,
385 		    ACPI_MIN(length, sizeof(struct acpi_table_fadt)));
386 
387 	/* Take a copy of the Hardware Reduced flag */
388 
389 	acpi_gbl_reduced_hardware = FALSE;
390 	if (acpi_gbl_FADT.flags & ACPI_FADT_HW_REDUCED) {
391 		acpi_gbl_reduced_hardware = TRUE;
392 	}
393 
394 	/* Convert the local copy of the FADT to the common internal format */
395 
396 	acpi_tb_convert_fadt();
397 
398 	/* Initialize the global ACPI register structures */
399 
400 	acpi_tb_setup_fadt_registers();
401 }
402 
403 /*******************************************************************************
404  *
405  * FUNCTION:    acpi_tb_convert_fadt
406  *
407  * PARAMETERS:  none - acpi_gbl_FADT is used.
408  *
409  * RETURN:      None
410  *
411  * DESCRIPTION: Converts all versions of the FADT to a common internal format.
412  *              Expand 32-bit addresses to 64-bit as necessary. Also validate
413  *              important fields within the FADT.
414  *
415  * NOTE:        acpi_gbl_FADT must be of size (struct acpi_table_fadt), and must
416  *              contain a copy of the actual BIOS-provided FADT.
417  *
418  * Notes on 64-bit register addresses:
419  *
420  * After this FADT conversion, later ACPICA code will only use the 64-bit "X"
421  * fields of the FADT for all ACPI register addresses.
422  *
423  * The 64-bit X fields are optional extensions to the original 32-bit FADT
424  * V1.0 fields. Even if they are present in the FADT, they are optional and
425  * are unused if the BIOS sets them to zero. Therefore, we must copy/expand
426  * 32-bit V1.0 fields to the 64-bit X fields if the the 64-bit X field is
427  * originally zero.
428  *
429  * For ACPI 1.0 FADTs (that contain no 64-bit addresses), all 32-bit address
430  * fields are expanded to the corresponding 64-bit X fields in the internal
431  * common FADT.
432  *
433  * For ACPI 2.0+ FADTs, all valid (non-zero) 32-bit address fields are expanded
434  * to the corresponding 64-bit X fields, if the 64-bit field is originally
435  * zero. Adhering to the ACPI specification, we completely ignore the 32-bit
436  * field if the 64-bit field is valid, regardless of whether the host OS is
437  * 32-bit or 64-bit.
438  *
439  * Possible additional checks:
440  *  (acpi_gbl_FADT.pm1_event_length >= 4)
441  *  (acpi_gbl_FADT.pm1_control_length >= 2)
442  *  (acpi_gbl_FADT.pm_timer_length >= 4)
443  *  Gpe block lengths must be multiple of 2
444  *
445  ******************************************************************************/
446 
447 static void acpi_tb_convert_fadt(void)
448 {
449 	char *name;
450 	struct acpi_generic_address *address64;
451 	u32 address32;
452 	u8 length;
453 	u32 i;
454 
455 	/*
456 	 * For ACPI 1.0 FADTs (revision 1 or 2), ensure that reserved fields which
457 	 * should be zero are indeed zero. This will workaround BIOSs that
458 	 * inadvertently place values in these fields.
459 	 *
460 	 * The ACPI 1.0 reserved fields that will be zeroed are the bytes located
461 	 * at offset 45, 55, 95, and the word located at offset 109, 110.
462 	 *
463 	 * Note: The FADT revision value is unreliable. Only the length can be
464 	 * trusted.
465 	 */
466 	if (acpi_gbl_FADT.header.length <= ACPI_FADT_V2_SIZE) {
467 		acpi_gbl_FADT.preferred_profile = 0;
468 		acpi_gbl_FADT.pstate_control = 0;
469 		acpi_gbl_FADT.cst_control = 0;
470 		acpi_gbl_FADT.boot_flags = 0;
471 	}
472 
473 	/*
474 	 * Now we can update the local FADT length to the length of the
475 	 * current FADT version as defined by the ACPI specification.
476 	 * Thus, we will have a common FADT internally.
477 	 */
478 	acpi_gbl_FADT.header.length = sizeof(struct acpi_table_fadt);
479 
480 	/*
481 	 * Expand the 32-bit FACS and DSDT addresses to 64-bit as necessary.
482 	 * Later ACPICA code will always use the X 64-bit field.
483 	 */
484 	acpi_gbl_FADT.Xfacs = acpi_tb_select_address("FACS",
485 						     acpi_gbl_FADT.facs,
486 						     acpi_gbl_FADT.Xfacs);
487 
488 	acpi_gbl_FADT.Xdsdt = acpi_tb_select_address("DSDT",
489 						     acpi_gbl_FADT.dsdt,
490 						     acpi_gbl_FADT.Xdsdt);
491 
492 	/* If Hardware Reduced flag is set, we are all done */
493 
494 	if (acpi_gbl_reduced_hardware) {
495 		return;
496 	}
497 
498 	/* Examine all of the 64-bit extended address fields (X fields) */
499 
500 	for (i = 0; i < ACPI_FADT_INFO_ENTRIES; i++) {
501 		/*
502 		 * Get the 32-bit and 64-bit addresses, as well as the register
503 		 * length and register name.
504 		 */
505 		address32 = *ACPI_ADD_PTR(u32,
506 					  &acpi_gbl_FADT,
507 					  fadt_info_table[i].address32);
508 
509 		address64 = ACPI_ADD_PTR(struct acpi_generic_address,
510 					 &acpi_gbl_FADT,
511 					 fadt_info_table[i].address64);
512 
513 		length = *ACPI_ADD_PTR(u8,
514 				       &acpi_gbl_FADT,
515 				       fadt_info_table[i].length);
516 
517 		name = fadt_info_table[i].name;
518 
519 		/*
520 		 * Expand the ACPI 1.0 32-bit addresses to the ACPI 2.0 64-bit "X"
521 		 * generic address structures as necessary. Later code will always use
522 		 * the 64-bit address structures.
523 		 *
524 		 * November 2013:
525 		 * Now always use the 64-bit address if it is valid (non-zero), in
526 		 * accordance with the ACPI specification which states that a 64-bit
527 		 * address supersedes the 32-bit version. This behavior can be
528 		 * overridden by the acpi_gbl_use32_bit_fadt_addresses flag.
529 		 *
530 		 * During 64-bit address construction and verification,
531 		 * these cases are handled:
532 		 *
533 		 * Address32 zero, Address64 [don't care]   - Use Address64
534 		 *
535 		 * Address32 non-zero, Address64 zero       - Copy/use Address32
536 		 * Address32 non-zero == Address64 non-zero - Use Address64
537 		 * Address32 non-zero != Address64 non-zero - Warning, use Address64
538 		 *
539 		 * Override: if acpi_gbl_use32_bit_fadt_addresses is TRUE, and:
540 		 * Address32 non-zero != Address64 non-zero - Warning, copy/use Address32
541 		 *
542 		 * Note: space_id is always I/O for 32-bit legacy address fields
543 		 */
544 		if (address32) {
545 			if (!address64->address) {
546 
547 				/* 64-bit address is zero, use 32-bit address */
548 
549 				acpi_tb_init_generic_address(address64,
550 							     ACPI_ADR_SPACE_SYSTEM_IO,
551 							     *ACPI_ADD_PTR(u8,
552 									   &acpi_gbl_FADT,
553 									   fadt_info_table
554 									   [i].
555 									   length),
556 							     (u64)address32,
557 							     name);
558 			} else if (address64->address != (u64)address32) {
559 
560 				/* Address mismatch */
561 
562 				ACPI_BIOS_WARNING((AE_INFO,
563 						   "32/64X address mismatch in FADT/%s: "
564 						   "0x%8.8X/0x%8.8X%8.8X, using %u-bit address",
565 						   name, address32,
566 						   ACPI_FORMAT_UINT64
567 						   (address64->address),
568 						   acpi_gbl_use32_bit_fadt_addresses
569 						   ? 32 : 64));
570 
571 				if (acpi_gbl_use32_bit_fadt_addresses) {
572 
573 					/* 32-bit address override */
574 
575 					acpi_tb_init_generic_address(address64,
576 								     ACPI_ADR_SPACE_SYSTEM_IO,
577 								     *ACPI_ADD_PTR
578 								     (u8,
579 								      &acpi_gbl_FADT,
580 								      fadt_info_table
581 								      [i].
582 								      length),
583 								     (u64)
584 								     address32,
585 								     name);
586 				}
587 			}
588 		}
589 
590 		/*
591 		 * For each extended field, check for length mismatch between the
592 		 * legacy length field and the corresponding 64-bit X length field.
593 		 * Note: If the legacy length field is > 0xFF bits, ignore this
594 		 * check. (GPE registers can be larger than the 64-bit GAS structure
595 		 * can accomodate, 0xFF bits).
596 		 */
597 		if (address64->address &&
598 		    (ACPI_MUL_8(length) <= ACPI_UINT8_MAX) &&
599 		    (address64->bit_width != ACPI_MUL_8(length))) {
600 			ACPI_BIOS_WARNING((AE_INFO,
601 					   "32/64X length mismatch in FADT/%s: %u/%u",
602 					   name, ACPI_MUL_8(length),
603 					   address64->bit_width));
604 		}
605 
606 		if (fadt_info_table[i].type & ACPI_FADT_REQUIRED) {
607 			/*
608 			 * Field is required (Pm1a_event, Pm1a_control).
609 			 * Both the address and length must be non-zero.
610 			 */
611 			if (!address64->address || !length) {
612 				ACPI_BIOS_ERROR((AE_INFO,
613 						 "Required FADT field %s has zero address and/or length: "
614 						 "0x%8.8X%8.8X/0x%X",
615 						 name,
616 						 ACPI_FORMAT_UINT64(address64->
617 								    address),
618 						 length));
619 			}
620 		} else if (fadt_info_table[i].type & ACPI_FADT_SEPARATE_LENGTH) {
621 			/*
622 			 * Field is optional (Pm2_control, GPE0, GPE1) AND has its own
623 			 * length field. If present, both the address and length must
624 			 * be valid.
625 			 */
626 			if ((address64->address && !length) ||
627 			    (!address64->address && length)) {
628 				ACPI_BIOS_WARNING((AE_INFO,
629 						   "Optional FADT field %s has zero address or length: "
630 						   "0x%8.8X%8.8X/0x%X",
631 						   name,
632 						   ACPI_FORMAT_UINT64
633 						   (address64->address),
634 						   length));
635 			}
636 		}
637 	}
638 }
639 
640 /*******************************************************************************
641  *
642  * FUNCTION:    acpi_tb_setup_fadt_registers
643  *
644  * PARAMETERS:  None, uses acpi_gbl_FADT.
645  *
646  * RETURN:      None
647  *
648  * DESCRIPTION: Initialize global ACPI PM1 register definitions. Optionally,
649  *              force FADT register definitions to their default lengths.
650  *
651  ******************************************************************************/
652 
653 static void acpi_tb_setup_fadt_registers(void)
654 {
655 	struct acpi_generic_address *target64;
656 	struct acpi_generic_address *source64;
657 	u8 pm1_register_byte_width;
658 	u32 i;
659 
660 	/*
661 	 * Optionally check all register lengths against the default values and
662 	 * update them if they are incorrect.
663 	 */
664 	if (acpi_gbl_use_default_register_widths) {
665 		for (i = 0; i < ACPI_FADT_INFO_ENTRIES; i++) {
666 			target64 =
667 			    ACPI_ADD_PTR(struct acpi_generic_address,
668 					 &acpi_gbl_FADT,
669 					 fadt_info_table[i].address64);
670 
671 			/*
672 			 * If a valid register (Address != 0) and the (default_length > 0)
673 			 * (Not a GPE register), then check the width against the default.
674 			 */
675 			if ((target64->address) &&
676 			    (fadt_info_table[i].default_length > 0) &&
677 			    (fadt_info_table[i].default_length !=
678 			     target64->bit_width)) {
679 				ACPI_BIOS_WARNING((AE_INFO,
680 						   "Invalid length for FADT/%s: %u, using default %u",
681 						   fadt_info_table[i].name,
682 						   target64->bit_width,
683 						   fadt_info_table[i].
684 						   default_length));
685 
686 				/* Incorrect size, set width to the default */
687 
688 				target64->bit_width =
689 				    fadt_info_table[i].default_length;
690 			}
691 		}
692 	}
693 
694 	/*
695 	 * Get the length of the individual PM1 registers (enable and status).
696 	 * Each register is defined to be (event block length / 2). Extra divide
697 	 * by 8 converts bits to bytes.
698 	 */
699 	pm1_register_byte_width = (u8)
700 	    ACPI_DIV_16(acpi_gbl_FADT.xpm1a_event_block.bit_width);
701 
702 	/*
703 	 * Calculate separate GAS structs for the PM1x (A/B) Status and Enable
704 	 * registers. These addresses do not appear (directly) in the FADT, so it
705 	 * is useful to pre-calculate them from the PM1 Event Block definitions.
706 	 *
707 	 * The PM event blocks are split into two register blocks, first is the
708 	 * PM Status Register block, followed immediately by the PM Enable
709 	 * Register block. Each is of length (pm1_event_length/2)
710 	 *
711 	 * Note: The PM1A event block is required by the ACPI specification.
712 	 * However, the PM1B event block is optional and is rarely, if ever,
713 	 * used.
714 	 */
715 
716 	for (i = 0; i < ACPI_FADT_PM_INFO_ENTRIES; i++) {
717 		source64 =
718 		    ACPI_ADD_PTR(struct acpi_generic_address, &acpi_gbl_FADT,
719 				 fadt_pm_info_table[i].source);
720 
721 		if (source64->address) {
722 			acpi_tb_init_generic_address(fadt_pm_info_table[i].
723 						     target, source64->space_id,
724 						     pm1_register_byte_width,
725 						     source64->address +
726 						     (fadt_pm_info_table[i].
727 						      register_num *
728 						      pm1_register_byte_width),
729 						     "PmRegisters");
730 		}
731 	}
732 }
733