xref: /openbmc/linux/drivers/acpi/acpica/tbfadt.c (revision 565d76cb)
1 /******************************************************************************
2  *
3  * Module Name: tbfadt   - FADT table utilities
4  *
5  *****************************************************************************/
6 
7 /*
8  * Copyright (C) 2000 - 2011, 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 ACPI_INLINE void
53 acpi_tb_init_generic_address(struct acpi_generic_address *generic_address,
54 			     u8 space_id, u8 byte_width, u64 address);
55 
56 static void acpi_tb_convert_fadt(void);
57 
58 static void acpi_tb_validate_fadt(void);
59 
60 static void acpi_tb_setup_fadt_registers(void);
61 
62 /* Table for conversion of FADT to common internal format and FADT validation */
63 
64 typedef struct acpi_fadt_info {
65 	char *name;
66 	u8 address64;
67 	u8 address32;
68 	u8 length;
69 	u8 default_length;
70 	u8 type;
71 
72 } acpi_fadt_info;
73 
74 #define ACPI_FADT_REQUIRED          1
75 #define ACPI_FADT_SEPARATE_LENGTH   2
76 
77 static struct acpi_fadt_info fadt_info_table[] = {
78 	{"Pm1aEventBlock",
79 	 ACPI_FADT_OFFSET(xpm1a_event_block),
80 	 ACPI_FADT_OFFSET(pm1a_event_block),
81 	 ACPI_FADT_OFFSET(pm1_event_length),
82 	 ACPI_PM1_REGISTER_WIDTH * 2,	/* Enable + Status register */
83 	 ACPI_FADT_REQUIRED},
84 
85 	{"Pm1bEventBlock",
86 	 ACPI_FADT_OFFSET(xpm1b_event_block),
87 	 ACPI_FADT_OFFSET(pm1b_event_block),
88 	 ACPI_FADT_OFFSET(pm1_event_length),
89 	 ACPI_PM1_REGISTER_WIDTH * 2,	/* Enable + Status register */
90 	 0},
91 
92 	{"Pm1aControlBlock",
93 	 ACPI_FADT_OFFSET(xpm1a_control_block),
94 	 ACPI_FADT_OFFSET(pm1a_control_block),
95 	 ACPI_FADT_OFFSET(pm1_control_length),
96 	 ACPI_PM1_REGISTER_WIDTH,
97 	 ACPI_FADT_REQUIRED},
98 
99 	{"Pm1bControlBlock",
100 	 ACPI_FADT_OFFSET(xpm1b_control_block),
101 	 ACPI_FADT_OFFSET(pm1b_control_block),
102 	 ACPI_FADT_OFFSET(pm1_control_length),
103 	 ACPI_PM1_REGISTER_WIDTH,
104 	 0},
105 
106 	{"Pm2ControlBlock",
107 	 ACPI_FADT_OFFSET(xpm2_control_block),
108 	 ACPI_FADT_OFFSET(pm2_control_block),
109 	 ACPI_FADT_OFFSET(pm2_control_length),
110 	 ACPI_PM2_REGISTER_WIDTH,
111 	 ACPI_FADT_SEPARATE_LENGTH},
112 
113 	{"PmTimerBlock",
114 	 ACPI_FADT_OFFSET(xpm_timer_block),
115 	 ACPI_FADT_OFFSET(pm_timer_block),
116 	 ACPI_FADT_OFFSET(pm_timer_length),
117 	 ACPI_PM_TIMER_WIDTH,
118 	 ACPI_FADT_REQUIRED},
119 
120 	{"Gpe0Block",
121 	 ACPI_FADT_OFFSET(xgpe0_block),
122 	 ACPI_FADT_OFFSET(gpe0_block),
123 	 ACPI_FADT_OFFSET(gpe0_block_length),
124 	 0,
125 	 ACPI_FADT_SEPARATE_LENGTH},
126 
127 	{"Gpe1Block",
128 	 ACPI_FADT_OFFSET(xgpe1_block),
129 	 ACPI_FADT_OFFSET(gpe1_block),
130 	 ACPI_FADT_OFFSET(gpe1_block_length),
131 	 0,
132 	 ACPI_FADT_SEPARATE_LENGTH}
133 };
134 
135 #define ACPI_FADT_INFO_ENTRIES \
136 			(sizeof (fadt_info_table) / sizeof (struct acpi_fadt_info))
137 
138 /* Table used to split Event Blocks into separate status/enable registers */
139 
140 typedef struct acpi_fadt_pm_info {
141 	struct acpi_generic_address *target;
142 	u8 source;
143 	u8 register_num;
144 
145 } acpi_fadt_pm_info;
146 
147 static struct acpi_fadt_pm_info fadt_pm_info_table[] = {
148 	{&acpi_gbl_xpm1a_status,
149 	 ACPI_FADT_OFFSET(xpm1a_event_block),
150 	 0},
151 
152 	{&acpi_gbl_xpm1a_enable,
153 	 ACPI_FADT_OFFSET(xpm1a_event_block),
154 	 1},
155 
156 	{&acpi_gbl_xpm1b_status,
157 	 ACPI_FADT_OFFSET(xpm1b_event_block),
158 	 0},
159 
160 	{&acpi_gbl_xpm1b_enable,
161 	 ACPI_FADT_OFFSET(xpm1b_event_block),
162 	 1}
163 };
164 
165 #define ACPI_FADT_PM_INFO_ENTRIES \
166 			(sizeof (fadt_pm_info_table) / sizeof (struct acpi_fadt_pm_info))
167 
168 /*******************************************************************************
169  *
170  * FUNCTION:    acpi_tb_init_generic_address
171  *
172  * PARAMETERS:  generic_address     - GAS struct to be initialized
173  *              byte_width          - Width of this register
174  *              Address             - Address of the register
175  *
176  * RETURN:      None
177  *
178  * DESCRIPTION: Initialize a Generic Address Structure (GAS)
179  *              See the ACPI specification for a full description and
180  *              definition of this structure.
181  *
182  ******************************************************************************/
183 
184 static ACPI_INLINE void
185 acpi_tb_init_generic_address(struct acpi_generic_address *generic_address,
186 			     u8 space_id, u8 byte_width, u64 address)
187 {
188 
189 	/*
190 	 * The 64-bit Address field is non-aligned in the byte packed
191 	 * GAS struct.
192 	 */
193 	ACPI_MOVE_64_TO_64(&generic_address->address, &address);
194 
195 	/* All other fields are byte-wide */
196 
197 	generic_address->space_id = space_id;
198 	generic_address->bit_width = (u8)ACPI_MUL_8(byte_width);
199 	generic_address->bit_offset = 0;
200 	generic_address->access_width = 0;	/* Access width ANY */
201 }
202 
203 /*******************************************************************************
204  *
205  * FUNCTION:    acpi_tb_parse_fadt
206  *
207  * PARAMETERS:  table_index         - Index for the FADT
208  *
209  * RETURN:      None
210  *
211  * DESCRIPTION: Initialize the FADT, DSDT and FACS tables
212  *              (FADT contains the addresses of the DSDT and FACS)
213  *
214  ******************************************************************************/
215 
216 void acpi_tb_parse_fadt(u32 table_index)
217 {
218 	u32 length;
219 	struct acpi_table_header *table;
220 
221 	/*
222 	 * The FADT has multiple versions with different lengths,
223 	 * and it contains pointers to both the DSDT and FACS tables.
224 	 *
225 	 * Get a local copy of the FADT and convert it to a common format
226 	 * Map entire FADT, assumed to be smaller than one page.
227 	 */
228 	length = acpi_gbl_root_table_list.tables[table_index].length;
229 
230 	table =
231 	    acpi_os_map_memory(acpi_gbl_root_table_list.tables[table_index].
232 			       address, length);
233 	if (!table) {
234 		return;
235 	}
236 
237 	/*
238 	 * Validate the FADT checksum before we copy the table. Ignore
239 	 * checksum error as we want to try to get the DSDT and FACS.
240 	 */
241 	(void)acpi_tb_verify_checksum(table, length);
242 
243 	/* Create a local copy of the FADT in common ACPI 2.0+ format */
244 
245 	acpi_tb_create_local_fadt(table, length);
246 
247 	/* All done with the real FADT, unmap it */
248 
249 	acpi_os_unmap_memory(table, length);
250 
251 	/* Obtain the DSDT and FACS tables via their addresses within the FADT */
252 
253 	acpi_tb_install_table((acpi_physical_address) acpi_gbl_FADT.Xdsdt,
254 			      ACPI_SIG_DSDT, ACPI_TABLE_INDEX_DSDT);
255 
256 	acpi_tb_install_table((acpi_physical_address) acpi_gbl_FADT.Xfacs,
257 			      ACPI_SIG_FACS, ACPI_TABLE_INDEX_FACS);
258 }
259 
260 /*******************************************************************************
261  *
262  * FUNCTION:    acpi_tb_create_local_fadt
263  *
264  * PARAMETERS:  Table               - Pointer to BIOS FADT
265  *              Length              - Length of the table
266  *
267  * RETURN:      None
268  *
269  * DESCRIPTION: Get a local copy of the FADT and convert it to a common format.
270  *              Performs validation on some important FADT fields.
271  *
272  * NOTE:        We create a local copy of the FADT regardless of the version.
273  *
274  ******************************************************************************/
275 
276 void acpi_tb_create_local_fadt(struct acpi_table_header *table, u32 length)
277 {
278 	/*
279 	 * Check if the FADT is larger than the largest table that we expect
280 	 * (the ACPI 2.0/3.0 version). If so, truncate the table, and issue
281 	 * a warning.
282 	 */
283 	if (length > sizeof(struct acpi_table_fadt)) {
284 		ACPI_WARNING((AE_INFO,
285 			      "FADT (revision %u) is longer than ACPI 2.0 version, "
286 			      "truncating length %u to %u",
287 			      table->revision, length,
288 			      (u32)sizeof(struct acpi_table_fadt)));
289 	}
290 
291 	/* Clear the entire local FADT */
292 
293 	ACPI_MEMSET(&acpi_gbl_FADT, 0, sizeof(struct acpi_table_fadt));
294 
295 	/* Copy the original FADT, up to sizeof (struct acpi_table_fadt) */
296 
297 	ACPI_MEMCPY(&acpi_gbl_FADT, table,
298 		    ACPI_MIN(length, sizeof(struct acpi_table_fadt)));
299 
300 	/* Convert the local copy of the FADT to the common internal format */
301 
302 	acpi_tb_convert_fadt();
303 
304 	/* Validate FADT values now, before we make any changes */
305 
306 	acpi_tb_validate_fadt();
307 
308 	/* Initialize the global ACPI register structures */
309 
310 	acpi_tb_setup_fadt_registers();
311 }
312 
313 /*******************************************************************************
314  *
315  * FUNCTION:    acpi_tb_convert_fadt
316  *
317  * PARAMETERS:  None, uses acpi_gbl_FADT
318  *
319  * RETURN:      None
320  *
321  * DESCRIPTION: Converts all versions of the FADT to a common internal format.
322  *              Expand 32-bit addresses to 64-bit as necessary.
323  *
324  * NOTE:        acpi_gbl_FADT must be of size (struct acpi_table_fadt),
325  *              and must contain a copy of the actual FADT.
326  *
327  * Notes on 64-bit register addresses:
328  *
329  * After this FADT conversion, later ACPICA code will only use the 64-bit "X"
330  * fields of the FADT for all ACPI register addresses.
331  *
332  * The 64-bit "X" fields are optional extensions to the original 32-bit FADT
333  * V1.0 fields. Even if they are present in the FADT, they are optional and
334  * are unused if the BIOS sets them to zero. Therefore, we must copy/expand
335  * 32-bit V1.0 fields if the corresponding X field is zero.
336  *
337  * For ACPI 1.0 FADTs, all 32-bit address fields are expanded to the
338  * corresponding "X" fields in the internal FADT.
339  *
340  * For ACPI 2.0+ FADTs, all valid (non-zero) 32-bit address fields are expanded
341  * to the corresponding 64-bit X fields. For compatibility with other ACPI
342  * implementations, we ignore the 64-bit field if the 32-bit field is valid,
343  * regardless of whether the host OS is 32-bit or 64-bit.
344  *
345  ******************************************************************************/
346 
347 static void acpi_tb_convert_fadt(void)
348 {
349 	struct acpi_generic_address *address64;
350 	u32 address32;
351 	u32 i;
352 
353 	/* Update the local FADT table header length */
354 
355 	acpi_gbl_FADT.header.length = sizeof(struct acpi_table_fadt);
356 
357 	/*
358 	 * Expand the 32-bit FACS and DSDT addresses to 64-bit as necessary.
359 	 * Later code will always use the X 64-bit field. Also, check for an
360 	 * address mismatch between the 32-bit and 64-bit address fields
361 	 * (FIRMWARE_CTRL/X_FIRMWARE_CTRL, DSDT/X_DSDT) which would indicate
362 	 * the presence of two FACS or two DSDT tables.
363 	 */
364 	if (!acpi_gbl_FADT.Xfacs) {
365 		acpi_gbl_FADT.Xfacs = (u64) acpi_gbl_FADT.facs;
366 	} else if (acpi_gbl_FADT.facs &&
367 		   (acpi_gbl_FADT.Xfacs != (u64) acpi_gbl_FADT.facs)) {
368 		ACPI_WARNING((AE_INFO,
369 		    "32/64 FACS address mismatch in FADT - two FACS tables!"));
370 	}
371 
372 	if (!acpi_gbl_FADT.Xdsdt) {
373 		acpi_gbl_FADT.Xdsdt = (u64) acpi_gbl_FADT.dsdt;
374 	} else if (acpi_gbl_FADT.dsdt &&
375 		   (acpi_gbl_FADT.Xdsdt != (u64) acpi_gbl_FADT.dsdt)) {
376 		ACPI_WARNING((AE_INFO,
377 		    "32/64 DSDT address mismatch in FADT - two DSDT tables!"));
378 	}
379 
380 	/*
381 	 * For ACPI 1.0 FADTs (revision 1 or 2), ensure that reserved fields which
382 	 * should be zero are indeed zero. This will workaround BIOSs that
383 	 * inadvertently place values in these fields.
384 	 *
385 	 * The ACPI 1.0 reserved fields that will be zeroed are the bytes located at
386 	 * offset 45, 55, 95, and the word located at offset 109, 110.
387 	 */
388 	if (acpi_gbl_FADT.header.revision < FADT2_REVISION_ID) {
389 		acpi_gbl_FADT.preferred_profile = 0;
390 		acpi_gbl_FADT.pstate_control = 0;
391 		acpi_gbl_FADT.cst_control = 0;
392 		acpi_gbl_FADT.boot_flags = 0;
393 	}
394 
395 	/*
396 	 * Expand the ACPI 1.0 32-bit addresses to the ACPI 2.0 64-bit "X"
397 	 * generic address structures as necessary. Later code will always use
398 	 * the 64-bit address structures.
399 	 *
400 	 * March 2009:
401 	 * We now always use the 32-bit address if it is valid (non-null). This
402 	 * is not in accordance with the ACPI specification which states that
403 	 * the 64-bit address supersedes the 32-bit version, but we do this for
404 	 * compatibility with other ACPI implementations. Most notably, in the
405 	 * case where both the 32 and 64 versions are non-null, we use the 32-bit
406 	 * version. This is the only address that is guaranteed to have been
407 	 * tested by the BIOS manufacturer.
408 	 */
409 	for (i = 0; i < ACPI_FADT_INFO_ENTRIES; i++) {
410 		address32 = *ACPI_ADD_PTR(u32,
411 					  &acpi_gbl_FADT,
412 					  fadt_info_table[i].address32);
413 
414 		address64 = ACPI_ADD_PTR(struct acpi_generic_address,
415 					 &acpi_gbl_FADT,
416 					 fadt_info_table[i].address64);
417 
418 		/*
419 		 * If both 32- and 64-bit addresses are valid (non-zero),
420 		 * they must match.
421 		 */
422 		if (address64->address && address32 &&
423 		    (address64->address != (u64) address32)) {
424 			ACPI_ERROR((AE_INFO,
425 				    "32/64X address mismatch in %s: 0x%8.8X/0x%8.8X%8.8X, using 32",
426 				    fadt_info_table[i].name, address32,
427 				    ACPI_FORMAT_UINT64(address64->address)));
428 		}
429 
430 		/* Always use 32-bit address if it is valid (non-null) */
431 
432 		if (address32) {
433 			/*
434 			 * Copy the 32-bit address to the 64-bit GAS structure. The
435 			 * Space ID is always I/O for 32-bit legacy address fields
436 			*/
437 			acpi_tb_init_generic_address(address64,
438 						     ACPI_ADR_SPACE_SYSTEM_IO,
439 						     *ACPI_ADD_PTR(u8,
440 								   &acpi_gbl_FADT,
441 								   fadt_info_table
442 								   [i].length),
443 						     (u64) address32);
444 		}
445 	}
446 }
447 
448 /*******************************************************************************
449  *
450  * FUNCTION:    acpi_tb_validate_fadt
451  *
452  * PARAMETERS:  Table           - Pointer to the FADT to be validated
453  *
454  * RETURN:      None
455  *
456  * DESCRIPTION: Validate various important fields within the FADT. If a problem
457  *              is found, issue a message, but no status is returned.
458  *              Used by both the table manager and the disassembler.
459  *
460  * Possible additional checks:
461  * (acpi_gbl_FADT.pm1_event_length >= 4)
462  * (acpi_gbl_FADT.pm1_control_length >= 2)
463  * (acpi_gbl_FADT.pm_timer_length >= 4)
464  * Gpe block lengths must be multiple of 2
465  *
466  ******************************************************************************/
467 
468 static void acpi_tb_validate_fadt(void)
469 {
470 	char *name;
471 	struct acpi_generic_address *address64;
472 	u8 length;
473 	u32 i;
474 
475 	/*
476 	 * Check for FACS and DSDT address mismatches. An address mismatch between
477 	 * the 32-bit and 64-bit address fields (FIRMWARE_CTRL/X_FIRMWARE_CTRL and
478 	 * DSDT/X_DSDT) would indicate the presence of two FACS or two DSDT tables.
479 	 */
480 	if (acpi_gbl_FADT.facs &&
481 	    (acpi_gbl_FADT.Xfacs != (u64) acpi_gbl_FADT.facs)) {
482 		ACPI_WARNING((AE_INFO,
483 			      "32/64X FACS address mismatch in FADT - "
484 			      "0x%8.8X/0x%8.8X%8.8X, using 32",
485 			      acpi_gbl_FADT.facs,
486 			      ACPI_FORMAT_UINT64(acpi_gbl_FADT.Xfacs)));
487 
488 		acpi_gbl_FADT.Xfacs = (u64) acpi_gbl_FADT.facs;
489 	}
490 
491 	if (acpi_gbl_FADT.dsdt &&
492 	    (acpi_gbl_FADT.Xdsdt != (u64) acpi_gbl_FADT.dsdt)) {
493 		ACPI_WARNING((AE_INFO,
494 			      "32/64X DSDT address mismatch in FADT - "
495 			      "0x%8.8X/0x%8.8X%8.8X, using 32",
496 			      acpi_gbl_FADT.dsdt,
497 			      ACPI_FORMAT_UINT64(acpi_gbl_FADT.Xdsdt)));
498 
499 		acpi_gbl_FADT.Xdsdt = (u64) acpi_gbl_FADT.dsdt;
500 	}
501 
502 	/* Examine all of the 64-bit extended address fields (X fields) */
503 
504 	for (i = 0; i < ACPI_FADT_INFO_ENTRIES; i++) {
505 		/*
506 		 * Generate pointer to the 64-bit address, get the register
507 		 * length (width) and the register name
508 		 */
509 		address64 = ACPI_ADD_PTR(struct acpi_generic_address,
510 					 &acpi_gbl_FADT,
511 					 fadt_info_table[i].address64);
512 		length =
513 		    *ACPI_ADD_PTR(u8, &acpi_gbl_FADT,
514 				  fadt_info_table[i].length);
515 		name = fadt_info_table[i].name;
516 
517 		/*
518 		 * For each extended field, check for length mismatch between the
519 		 * legacy length field and the corresponding 64-bit X length field.
520 		 */
521 		if (address64->address &&
522 		    (address64->bit_width != ACPI_MUL_8(length))) {
523 			ACPI_WARNING((AE_INFO,
524 				      "32/64X length mismatch in %s: %u/%u",
525 				      name, ACPI_MUL_8(length),
526 				      address64->bit_width));
527 		}
528 
529 		if (fadt_info_table[i].type & ACPI_FADT_REQUIRED) {
530 			/*
531 			 * Field is required (Pm1a_event, Pm1a_control, pm_timer).
532 			 * Both the address and length must be non-zero.
533 			 */
534 			if (!address64->address || !length) {
535 				ACPI_ERROR((AE_INFO,
536 					    "Required field %s has zero address and/or length:"
537 					    " 0x%8.8X%8.8X/0x%X",
538 					    name,
539 					    ACPI_FORMAT_UINT64(address64->
540 							       address),
541 					    length));
542 			}
543 		} else if (fadt_info_table[i].type & ACPI_FADT_SEPARATE_LENGTH) {
544 			/*
545 			 * Field is optional (PM2Control, GPE0, GPE1) AND has its own
546 			 * length field. If present, both the address and length must
547 			 * be valid.
548 			 */
549 			if ((address64->address && !length) ||
550 			    (!address64->address && length)) {
551 				ACPI_WARNING((AE_INFO,
552 					      "Optional field %s has zero address or length: "
553 					      "0x%8.8X%8.8X/0x%X",
554 					      name,
555 					      ACPI_FORMAT_UINT64(address64->
556 								 address),
557 					      length));
558 			}
559 		}
560 	}
561 }
562 
563 /*******************************************************************************
564  *
565  * FUNCTION:    acpi_tb_setup_fadt_registers
566  *
567  * PARAMETERS:  None, uses acpi_gbl_FADT.
568  *
569  * RETURN:      None
570  *
571  * DESCRIPTION: Initialize global ACPI PM1 register definitions. Optionally,
572  *              force FADT register definitions to their default lengths.
573  *
574  ******************************************************************************/
575 
576 static void acpi_tb_setup_fadt_registers(void)
577 {
578 	struct acpi_generic_address *target64;
579 	struct acpi_generic_address *source64;
580 	u8 pm1_register_byte_width;
581 	u32 i;
582 
583 	/*
584 	 * Optionally check all register lengths against the default values and
585 	 * update them if they are incorrect.
586 	 */
587 	if (acpi_gbl_use_default_register_widths) {
588 		for (i = 0; i < ACPI_FADT_INFO_ENTRIES; i++) {
589 			target64 =
590 			    ACPI_ADD_PTR(struct acpi_generic_address,
591 					 &acpi_gbl_FADT,
592 					 fadt_info_table[i].address64);
593 
594 			/*
595 			 * If a valid register (Address != 0) and the (default_length > 0)
596 			 * (Not a GPE register), then check the width against the default.
597 			 */
598 			if ((target64->address) &&
599 			    (fadt_info_table[i].default_length > 0) &&
600 			    (fadt_info_table[i].default_length !=
601 			     target64->bit_width)) {
602 				ACPI_WARNING((AE_INFO,
603 					      "Invalid length for %s: %u, using default %u",
604 					      fadt_info_table[i].name,
605 					      target64->bit_width,
606 					      fadt_info_table[i].
607 					      default_length));
608 
609 				/* Incorrect size, set width to the default */
610 
611 				target64->bit_width =
612 				    fadt_info_table[i].default_length;
613 			}
614 		}
615 	}
616 
617 	/*
618 	 * Get the length of the individual PM1 registers (enable and status).
619 	 * Each register is defined to be (event block length / 2). Extra divide
620 	 * by 8 converts bits to bytes.
621 	 */
622 	pm1_register_byte_width = (u8)
623 	    ACPI_DIV_16(acpi_gbl_FADT.xpm1a_event_block.bit_width);
624 
625 	/*
626 	 * Calculate separate GAS structs for the PM1x (A/B) Status and Enable
627 	 * registers. These addresses do not appear (directly) in the FADT, so it
628 	 * is useful to pre-calculate them from the PM1 Event Block definitions.
629 	 *
630 	 * The PM event blocks are split into two register blocks, first is the
631 	 * PM Status Register block, followed immediately by the PM Enable
632 	 * Register block. Each is of length (pm1_event_length/2)
633 	 *
634 	 * Note: The PM1A event block is required by the ACPI specification.
635 	 * However, the PM1B event block is optional and is rarely, if ever,
636 	 * used.
637 	 */
638 
639 	for (i = 0; i < ACPI_FADT_PM_INFO_ENTRIES; i++) {
640 		source64 =
641 		    ACPI_ADD_PTR(struct acpi_generic_address, &acpi_gbl_FADT,
642 				 fadt_pm_info_table[i].source);
643 
644 		if (source64->address) {
645 			acpi_tb_init_generic_address(fadt_pm_info_table[i].
646 						     target, source64->space_id,
647 						     pm1_register_byte_width,
648 						     source64->address +
649 						     (fadt_pm_info_table[i].
650 						      register_num *
651 						      pm1_register_byte_width));
652 		}
653 	}
654 }
655