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
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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);