1 /******************************************************************************
3 * Module Name: tbxfroot - Find the root ACPI table (RSDT)
5 *****************************************************************************/
8 * Copyright (C) 2000 - 2005, R. Byron Moore
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
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.
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.
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.
44 #include <linux/module.h>
46 #include <acpi/acpi.h>
47 #include <acpi/actables.h>
49 #define _COMPONENT ACPI_TABLES
50 ACPI_MODULE_NAME("tbxfroot")
52 /* Local prototypes */
54 acpi_tb_find_rsdp(struct acpi_table_desc
*table_info
, u32 flags
);
56 static u8
*acpi_tb_scan_memory_for_rsdp(u8
* start_address
, u32 length
);
58 /*******************************************************************************
60 * FUNCTION: acpi_tb_validate_rsdp
62 * PARAMETERS: Rsdp - Pointer to unvalidated RSDP
66 * DESCRIPTION: Validate the RSDP (ptr)
68 ******************************************************************************/
70 acpi_status
acpi_tb_validate_rsdp(struct rsdp_descriptor
*rsdp
)
72 ACPI_FUNCTION_ENTRY();
75 * The signature and checksum must both be correct
77 if (ACPI_STRNCMP((char *)rsdp
, RSDP_SIG
, sizeof(RSDP_SIG
) - 1) != 0) {
78 /* Nope, BAD Signature */
80 return (AE_BAD_SIGNATURE
);
83 /* Check the standard checksum */
85 if (acpi_tb_generate_checksum(rsdp
, ACPI_RSDP_CHECKSUM_LENGTH
) != 0) {
86 return (AE_BAD_CHECKSUM
);
89 /* Check extended checksum if table version >= 2 */
91 if ((rsdp
->revision
>= 2) &&
92 (acpi_tb_generate_checksum(rsdp
, ACPI_RSDP_XCHECKSUM_LENGTH
) !=
94 return (AE_BAD_CHECKSUM
);
100 /*******************************************************************************
102 * FUNCTION: acpi_tb_find_table
104 * PARAMETERS: Signature - String with ACPI table signature
105 * oem_id - String with the table OEM ID
106 * oem_table_id - String with the OEM Table ID
107 * table_ptr - Where the table pointer is returned
111 * DESCRIPTION: Find an ACPI table (in the RSDT/XSDT) that matches the
112 * Signature, OEM ID and OEM Table ID.
114 ******************************************************************************/
117 acpi_tb_find_table(char *signature
,
119 char *oem_table_id
, struct acpi_table_header
** table_ptr
)
122 struct acpi_table_header
*table
;
124 ACPI_FUNCTION_TRACE("tb_find_table");
126 /* Validate string lengths */
128 if ((ACPI_STRLEN(signature
) > ACPI_NAME_SIZE
) ||
129 (ACPI_STRLEN(oem_id
) > sizeof(table
->oem_id
)) ||
130 (ACPI_STRLEN(oem_table_id
) > sizeof(table
->oem_table_id
))) {
131 return_ACPI_STATUS(AE_AML_STRING_LIMIT
);
134 if (!ACPI_STRNCMP(signature
, DSDT_SIG
, ACPI_NAME_SIZE
)) {
136 * The DSDT pointer is contained in the FADT, not the RSDT.
137 * This code should suffice, because the only code that would perform
138 * a "find" on the DSDT is the data_table_region() AML opcode -- in
139 * which case, the DSDT is guaranteed to be already loaded.
140 * If this becomes insufficient, the FADT will have to be found first.
142 if (!acpi_gbl_DSDT
) {
143 return_ACPI_STATUS(AE_NO_ACPI_TABLES
);
145 table
= acpi_gbl_DSDT
;
149 status
= acpi_get_firmware_table(signature
, 1,
150 ACPI_LOGICAL_ADDRESSING
,
152 if (ACPI_FAILURE(status
)) {
153 return_ACPI_STATUS(status
);
157 /* Check oem_id and oem_table_id */
159 if ((oem_id
[0] && ACPI_STRNCMP(oem_id
, table
->oem_id
,
160 sizeof(table
->oem_id
))) ||
161 (oem_table_id
[0] && ACPI_STRNCMP(oem_table_id
, table
->oem_table_id
,
162 sizeof(table
->oem_table_id
)))) {
163 return_ACPI_STATUS(AE_AML_NAME_NOT_FOUND
);
166 ACPI_DEBUG_PRINT((ACPI_DB_TABLES
, "Found table [%4.4s]\n",
170 return_ACPI_STATUS(AE_OK
);
173 /*******************************************************************************
175 * FUNCTION: acpi_get_firmware_table
177 * PARAMETERS: Signature - Any ACPI table signature
178 * Instance - the non zero instance of the table, allows
179 * support for multiple tables of the same type
180 * Flags - Physical/Virtual support
181 * table_pointer - Where a buffer containing the table is
186 * DESCRIPTION: This function is called to get an ACPI table. A buffer is
187 * allocated for the table and returned in table_pointer.
188 * This table will be a complete table including the header.
190 ******************************************************************************/
193 acpi_get_firmware_table(acpi_string signature
,
195 u32 flags
, struct acpi_table_header
**table_pointer
)
198 struct acpi_pointer address
;
199 struct acpi_table_header
*header
= NULL
;
200 struct acpi_table_desc
*table_info
= NULL
;
201 struct acpi_table_desc
*rsdt_info
;
206 ACPI_FUNCTION_TRACE("acpi_get_firmware_table");
209 * Ensure that at least the table manager is initialized. We don't
210 * require that the entire ACPI subsystem is up for this interface.
211 * If we have a buffer, we must have a length too
213 if ((instance
== 0) || (!signature
) || (!table_pointer
)) {
214 return_ACPI_STATUS(AE_BAD_PARAMETER
);
217 /* Ensure that we have a RSDP */
219 if (!acpi_gbl_RSDP
) {
222 status
= acpi_os_get_root_pointer(flags
, &address
);
223 if (ACPI_FAILURE(status
)) {
224 ACPI_DEBUG_PRINT((ACPI_DB_INFO
, "RSDP not found\n"));
225 return_ACPI_STATUS(AE_NO_ACPI_TABLES
);
228 /* Map and validate the RSDP */
230 if ((flags
& ACPI_MEMORY_MODE
) == ACPI_LOGICAL_ADDRESSING
) {
231 status
= acpi_os_map_memory(address
.pointer
.physical
,
234 (void *)&acpi_gbl_RSDP
);
235 if (ACPI_FAILURE(status
)) {
236 return_ACPI_STATUS(status
);
239 acpi_gbl_RSDP
= address
.pointer
.logical
;
242 /* The RDSP signature and checksum must both be correct */
244 status
= acpi_tb_validate_rsdp(acpi_gbl_RSDP
);
245 if (ACPI_FAILURE(status
)) {
246 return_ACPI_STATUS(status
);
250 /* Get the RSDT address via the RSDP */
252 acpi_tb_get_rsdt_address(&address
);
253 ACPI_DEBUG_PRINT((ACPI_DB_INFO
,
254 "RSDP located at %p, RSDT physical=%8.8X%8.8X \n",
256 ACPI_FORMAT_UINT64(address
.pointer
.value
)));
258 /* Insert processor_mode flags */
260 address
.pointer_type
|= flags
;
262 /* Get and validate the RSDT */
264 rsdt_info
= ACPI_MEM_CALLOCATE(sizeof(struct acpi_table_desc
));
266 return_ACPI_STATUS(AE_NO_MEMORY
);
269 status
= acpi_tb_get_table(&address
, rsdt_info
);
270 if (ACPI_FAILURE(status
)) {
274 status
= acpi_tb_validate_rsdt(rsdt_info
->pointer
);
275 if (ACPI_FAILURE(status
)) {
279 /* Allocate a scratch table header and table descriptor */
281 header
= ACPI_MEM_ALLOCATE(sizeof(struct acpi_table_header
));
283 status
= AE_NO_MEMORY
;
287 table_info
= ACPI_MEM_ALLOCATE(sizeof(struct acpi_table_desc
));
289 status
= AE_NO_MEMORY
;
293 /* Get the number of table pointers within the RSDT */
296 acpi_tb_get_table_count(acpi_gbl_RSDP
, rsdt_info
->pointer
);
297 address
.pointer_type
= acpi_gbl_table_flags
| flags
;
300 * Search the RSDT/XSDT for the correct instance of the
303 for (i
= 0, j
= 0; i
< table_count
; i
++) {
305 * Get the next table pointer, handle RSDT vs. XSDT
306 * RSDT pointers are 32 bits, XSDT pointers are 64 bits
308 if (acpi_gbl_root_table_type
== ACPI_TABLE_TYPE_RSDT
) {
309 address
.pointer
.value
=
312 rsdt_info
->pointer
))->table_offset_entry
[i
];
314 address
.pointer
.value
=
317 rsdt_info
->pointer
))->table_offset_entry
[i
];
320 /* Get the table header */
322 status
= acpi_tb_get_table_header(&address
, header
);
323 if (ACPI_FAILURE(status
)) {
327 /* Compare table signatures and table instance */
329 if (!ACPI_STRNCMP(header
->signature
, signature
, ACPI_NAME_SIZE
)) {
330 /* An instance of the table was found */
334 /* Found the correct instance, get the entire table */
337 acpi_tb_get_table_body(&address
, header
,
339 if (ACPI_FAILURE(status
)) {
343 *table_pointer
= table_info
->pointer
;
349 /* Did not find the table */
351 status
= AE_NOT_EXIST
;
354 if (rsdt_info
->pointer
) {
355 acpi_os_unmap_memory(rsdt_info
->pointer
,
356 (acpi_size
) rsdt_info
->pointer
->length
);
358 ACPI_MEM_FREE(rsdt_info
);
361 ACPI_MEM_FREE(header
);
364 ACPI_MEM_FREE(table_info
);
366 return_ACPI_STATUS(status
);
369 EXPORT_SYMBOL(acpi_get_firmware_table
);
371 /* TBD: Move to a new file */
373 #if ACPI_MACHINE_WIDTH != 16
375 /*******************************************************************************
377 * FUNCTION: acpi_find_root_pointer
379 * PARAMETERS: Flags - Logical/Physical addressing
380 * rsdp_address - Where to place the RSDP address
382 * RETURN: Status, Physical address of the RSDP
384 * DESCRIPTION: Find the RSDP
386 ******************************************************************************/
388 acpi_status
acpi_find_root_pointer(u32 flags
, struct acpi_pointer
*rsdp_address
)
390 struct acpi_table_desc table_info
;
393 ACPI_FUNCTION_TRACE("acpi_find_root_pointer");
397 status
= acpi_tb_find_rsdp(&table_info
, flags
);
398 if (ACPI_FAILURE(status
)) {
399 ACPI_DEBUG_PRINT((ACPI_DB_ERROR
,
400 "RSDP structure not found, %s Flags=%X\n",
401 acpi_format_exception(status
), flags
));
403 return_ACPI_STATUS(AE_NO_ACPI_TABLES
);
406 rsdp_address
->pointer_type
= ACPI_PHYSICAL_POINTER
;
407 rsdp_address
->pointer
.physical
= table_info
.physical_address
;
408 return_ACPI_STATUS(AE_OK
);
411 /*******************************************************************************
413 * FUNCTION: acpi_tb_scan_memory_for_rsdp
415 * PARAMETERS: start_address - Starting pointer for search
416 * Length - Maximum length to search
418 * RETURN: Pointer to the RSDP if found, otherwise NULL.
420 * DESCRIPTION: Search a block of memory for the RSDP signature
422 ******************************************************************************/
424 static u8
*acpi_tb_scan_memory_for_rsdp(u8
* start_address
, u32 length
)
430 ACPI_FUNCTION_TRACE("tb_scan_memory_for_rsdp");
432 end_address
= start_address
+ length
;
434 /* Search from given start address for the requested length */
436 for (mem_rover
= start_address
; mem_rover
< end_address
;
437 mem_rover
+= ACPI_RSDP_SCAN_STEP
) {
438 /* The RSDP signature and checksum must both be correct */
441 acpi_tb_validate_rsdp(ACPI_CAST_PTR
442 (struct rsdp_descriptor
, mem_rover
));
443 if (ACPI_SUCCESS(status
)) {
444 /* Sig and checksum valid, we have found a real RSDP */
446 ACPI_DEBUG_PRINT((ACPI_DB_INFO
,
447 "RSDP located at physical address %p\n",
449 return_PTR(mem_rover
);
452 /* No sig match or bad checksum, keep searching */
455 /* Searched entire block, no RSDP was found */
457 ACPI_DEBUG_PRINT((ACPI_DB_INFO
,
458 "Searched entire block from %p, valid RSDP was not found\n",
463 /*******************************************************************************
465 * FUNCTION: acpi_tb_find_rsdp
467 * PARAMETERS: table_info - Where the table info is returned
468 * Flags - Current memory mode (logical vs.
469 * physical addressing)
471 * RETURN: Status, RSDP physical address
473 * DESCRIPTION: search lower 1_mbyte of memory for the root system descriptor
474 * pointer structure. If it is found, set *RSDP to point to it.
476 * NOTE1: The RSDp must be either in the first 1_k of the Extended
477 * BIOS Data Area or between E0000 and FFFFF (From ACPI Spec.)
478 * Only a 32-bit physical address is necessary.
480 * NOTE2: This function is always available, regardless of the
481 * initialization state of the rest of ACPI.
483 ******************************************************************************/
486 acpi_tb_find_rsdp(struct acpi_table_desc
*table_info
, u32 flags
)
490 u32 physical_address
;
493 ACPI_FUNCTION_TRACE("tb_find_rsdp");
496 * Scan supports either logical addressing or physical addressing
498 if ((flags
& ACPI_MEMORY_MODE
) == ACPI_LOGICAL_ADDRESSING
) {
499 /* 1a) Get the location of the Extended BIOS Data Area (EBDA) */
501 status
= acpi_os_map_memory((acpi_physical_address
)
502 ACPI_EBDA_PTR_LOCATION
,
503 ACPI_EBDA_PTR_LENGTH
,
505 if (ACPI_FAILURE(status
)) {
506 ACPI_DEBUG_PRINT((ACPI_DB_ERROR
,
507 "Could not map memory at %8.8X for length %X\n",
508 ACPI_EBDA_PTR_LOCATION
,
509 ACPI_EBDA_PTR_LENGTH
));
511 return_ACPI_STATUS(status
);
514 ACPI_MOVE_16_TO_32(&physical_address
, table_ptr
);
516 /* Convert segment part to physical address */
518 physical_address
<<= 4;
519 acpi_os_unmap_memory(table_ptr
, ACPI_EBDA_PTR_LENGTH
);
523 if (physical_address
> 0x400) {
525 * 1b) Search EBDA paragraphs (EBDa is required to be a
526 * minimum of 1_k length)
528 status
= acpi_os_map_memory((acpi_physical_address
)
530 ACPI_EBDA_WINDOW_SIZE
,
532 if (ACPI_FAILURE(status
)) {
533 ACPI_DEBUG_PRINT((ACPI_DB_ERROR
,
534 "Could not map memory at %8.8X for length %X\n",
536 ACPI_EBDA_WINDOW_SIZE
));
538 return_ACPI_STATUS(status
);
541 mem_rover
= acpi_tb_scan_memory_for_rsdp(table_ptr
,
542 ACPI_EBDA_WINDOW_SIZE
);
543 acpi_os_unmap_memory(table_ptr
, ACPI_EBDA_WINDOW_SIZE
);
546 /* Return the physical address */
549 ACPI_PTR_DIFF(mem_rover
, table_ptr
);
551 table_info
->physical_address
=
552 (acpi_physical_address
) physical_address
;
553 return_ACPI_STATUS(AE_OK
);
558 * 2) Search upper memory: 16-byte boundaries in E0000h-FFFFFh
560 status
= acpi_os_map_memory((acpi_physical_address
)
561 ACPI_HI_RSDP_WINDOW_BASE
,
562 ACPI_HI_RSDP_WINDOW_SIZE
,
565 if (ACPI_FAILURE(status
)) {
566 ACPI_DEBUG_PRINT((ACPI_DB_ERROR
,
567 "Could not map memory at %8.8X for length %X\n",
568 ACPI_HI_RSDP_WINDOW_BASE
,
569 ACPI_HI_RSDP_WINDOW_SIZE
));
571 return_ACPI_STATUS(status
);
575 acpi_tb_scan_memory_for_rsdp(table_ptr
,
576 ACPI_HI_RSDP_WINDOW_SIZE
);
577 acpi_os_unmap_memory(table_ptr
, ACPI_HI_RSDP_WINDOW_SIZE
);
580 /* Return the physical address */
583 ACPI_HI_RSDP_WINDOW_BASE
+ ACPI_PTR_DIFF(mem_rover
,
586 table_info
->physical_address
=
587 (acpi_physical_address
) physical_address
;
588 return_ACPI_STATUS(AE_OK
);
593 * Physical addressing
596 /* 1a) Get the location of the EBDA */
598 ACPI_MOVE_16_TO_32(&physical_address
, ACPI_EBDA_PTR_LOCATION
);
599 physical_address
<<= 4; /* Convert segment to physical address */
603 if (physical_address
> 0x400) {
605 * 1b) Search EBDA paragraphs (EBDa is required to be a minimum of
609 acpi_tb_scan_memory_for_rsdp(ACPI_PHYSADDR_TO_PTR
611 ACPI_EBDA_WINDOW_SIZE
);
613 /* Return the physical address */
615 table_info
->physical_address
=
616 ACPI_TO_INTEGER(mem_rover
);
617 return_ACPI_STATUS(AE_OK
);
621 /* 2) Search upper memory: 16-byte boundaries in E0000h-FFFFFh */
624 acpi_tb_scan_memory_for_rsdp(ACPI_PHYSADDR_TO_PTR
625 (ACPI_HI_RSDP_WINDOW_BASE
),
626 ACPI_HI_RSDP_WINDOW_SIZE
);
628 /* Found it, return the physical address */
630 table_info
->physical_address
=
631 ACPI_TO_INTEGER(mem_rover
);
632 return_ACPI_STATUS(AE_OK
);
636 /* A valid RSDP was not found */
638 ACPI_REPORT_ERROR(("No valid RSDP was found\n"));
639 return_ACPI_STATUS(AE_NOT_FOUND
);