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/******************************************************************************
*
* Module Name: tbxfroot - Find the root ACPI table (RSDT)
* $Revision: 52 $
*
*****************************************************************************/
/*
* Copyright (C) 2000, 2001 R. Byron Moore
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include "acpi.h"
#include "achware.h"
#include "actables.h"
#define _COMPONENT ACPI_TABLES
MODULE_NAME ("tbxfroot")
#define RSDP_CHECKSUM_LENGTH 20
/*******************************************************************************
*
* FUNCTION: Acpi_find_root_pointer
*
* PARAMETERS: **Rsdp_physical_address - Where to place the RSDP address
* Flags - Logical/Physical addressing
*
* RETURN: Status, Physical address of the RSDP
*
* DESCRIPTION: Find the RSDP
*
******************************************************************************/
acpi_status
acpi_find_root_pointer (
u32 flags,
ACPI_PHYSICAL_ADDRESS *rsdp_physical_address)
{
acpi_table_desc table_info;
acpi_status status;
FUNCTION_TRACE ("Acpi_find_root_pointer");
/* Get the RSDP */
status = acpi_tb_find_rsdp (&table_info, flags);
if (ACPI_FAILURE (status)) {
ACPI_DEBUG_PRINT ((ACPI_DB_ERROR, "RSDP structure not found\n"));
return_ACPI_STATUS (AE_NO_ACPI_TABLES);
}
*rsdp_physical_address = table_info.physical_address;
return_ACPI_STATUS (AE_OK);
}
/*******************************************************************************
*
* FUNCTION: Acpi_tb_scan_memory_for_rsdp
*
* PARAMETERS: Start_address - Starting pointer for search
* Length - Maximum length to search
*
* RETURN: Pointer to the RSDP if found, otherwise NULL.
*
* DESCRIPTION: Search a block of memory for the RSDP signature
*
******************************************************************************/
u8 *
acpi_tb_scan_memory_for_rsdp (
u8 *start_address,
u32 length)
{
u32 offset;
u8 *mem_rover;
FUNCTION_TRACE ("Tb_scan_memory_for_rsdp");
/* Search from given start addr for the requested length */
for (offset = 0, mem_rover = start_address;
offset < length;
offset += RSDP_SCAN_STEP, mem_rover += RSDP_SCAN_STEP) {
/* The signature and checksum must both be correct */
if (STRNCMP ((NATIVE_CHAR *) mem_rover,
RSDP_SIG, sizeof (RSDP_SIG)-1) == 0 &&
acpi_tb_checksum (mem_rover, RSDP_CHECKSUM_LENGTH) == 0) {
/* If so, we have found the RSDP */
ACPI_DEBUG_PRINT ((ACPI_DB_INFO,
"RSDP located at physical address %p\n",mem_rover));
return_PTR (mem_rover);
}
}
/* Searched entire block, no RSDP was found */
ACPI_DEBUG_PRINT ((ACPI_DB_INFO,"Searched entire block, no RSDP was found.\n"));
return_PTR (NULL);
}
/*******************************************************************************
*
* FUNCTION: Acpi_tb_find_rsdp
*
* PARAMETERS: *Table_info - Where the table info is returned
* Flags - Current memory mode (logical vs.
* physical addressing)
*
* RETURN: Status
*
* DESCRIPTION: Search lower 1_mbyte of memory for the root system descriptor
* pointer structure. If it is found, set *RSDP to point to it.
*
* NOTE: The RSDP must be either in the first 1_k of the Extended
* BIOS Data Area or between E0000 and FFFFF (ACPI 1.0 section
* 5.2.2; assertion #421).
*
******************************************************************************/
acpi_status
acpi_tb_find_rsdp (
acpi_table_desc *table_info,
u32 flags)
{
u8 *table_ptr;
u8 *mem_rover;
u64 phys_addr;
acpi_status status = AE_OK;
FUNCTION_TRACE ("Tb_find_rsdp");
/*
* Scan supports either 1) Logical addressing or 2) Physical addressing
*/
if ((flags & ACPI_MEMORY_MODE) == ACPI_LOGICAL_ADDRESSING) {
/*
* 1) Search EBDA (low memory) paragraphs
*/
status = acpi_os_map_memory (LO_RSDP_WINDOW_BASE, LO_RSDP_WINDOW_SIZE,
(void **) &table_ptr);
if (ACPI_FAILURE (status)) {
return_ACPI_STATUS (status);
}
mem_rover = acpi_tb_scan_memory_for_rsdp (table_ptr, LO_RSDP_WINDOW_SIZE);
acpi_os_unmap_memory (table_ptr, LO_RSDP_WINDOW_SIZE);
if (mem_rover) {
/* Found it, return the physical address */
phys_addr = LO_RSDP_WINDOW_BASE;
phys_addr += (mem_rover - table_ptr);
table_info->physical_address = phys_addr;
return_ACPI_STATUS (AE_OK);
}
/*
* 2) Search upper memory: 16-byte boundaries in E0000h-F0000h
*/
status = acpi_os_map_memory (HI_RSDP_WINDOW_BASE, HI_RSDP_WINDOW_SIZE,
(void **) &table_ptr);
if (ACPI_FAILURE (status)) {
return_ACPI_STATUS (status);
}
mem_rover = acpi_tb_scan_memory_for_rsdp (table_ptr, HI_RSDP_WINDOW_SIZE);
acpi_os_unmap_memory (table_ptr, HI_RSDP_WINDOW_SIZE);
if (mem_rover) {
/* Found it, return the physical address */
phys_addr = HI_RSDP_WINDOW_BASE;
phys_addr += (mem_rover - table_ptr);
table_info->physical_address = phys_addr;
return_ACPI_STATUS (AE_OK);
}
}
/*
* Physical addressing
*/
else {
/*
* 1) Search EBDA (low memory) paragraphs
*/
mem_rover = acpi_tb_scan_memory_for_rsdp ((u8 *) LO_RSDP_WINDOW_BASE,
LO_RSDP_WINDOW_SIZE);
if (mem_rover) {
/* Found it, return the physical address */
table_info->physical_address = (ACPI_TBLPTR) mem_rover;
return_ACPI_STATUS (AE_OK);
}
/*
* 2) Search upper memory: 16-byte boundaries in E0000h-F0000h
*/
mem_rover = acpi_tb_scan_memory_for_rsdp ((u8 *) HI_RSDP_WINDOW_BASE,
HI_RSDP_WINDOW_SIZE);
if (mem_rover) {
/* Found it, return the physical address */
table_info->physical_address = (ACPI_TBLPTR) mem_rover;
return_ACPI_STATUS (AE_OK);
}
}
/* RSDP signature was not found */
return_ACPI_STATUS (AE_NOT_FOUND);
}
/*******************************************************************************
*
* FUNCTION: Acpi_get_firmware_table
*
* PARAMETERS: Signature - Any ACPI table signature
* Instance - the non zero instance of the table, allows
* support for multiple tables of the same type
* Flags - 0: Physical/Virtual support
* Ret_buffer - pointer to a structure containing a buffer to
* receive the table
*
* RETURN: Status
*
* DESCRIPTION: This function is called to get an ACPI table. The caller
* supplies an Out_buffer large enough to contain the entire ACPI
* table. Upon completion
* the Out_buffer->Length field will indicate the number of bytes
* copied into the Out_buffer->Buf_ptr buffer. This table will be
* a complete table including the header.
*
******************************************************************************/
acpi_status
acpi_get_firmware_table (
acpi_string signature,
u32 instance,
u32 flags,
acpi_table_header **table_pointer)
{
ACPI_PHYSICAL_ADDRESS physical_address;
acpi_table_header *rsdt_ptr = NULL;
acpi_table_header *table_ptr;
acpi_status status;
u32 rsdt_size = 0;
u32 table_size;
u32 table_count;
u32 i;
u32 j;
FUNCTION_TRACE ("Acpi_get_firmware_table");
/*
* Ensure that at least the table manager is initialized. We don't
* require that the entire ACPI subsystem is up for this interface
*/
/*
* If we have a buffer, we must have a length too
*/
if ((instance == 0) ||
(!signature) ||
(!table_pointer)) {
return_ACPI_STATUS (AE_BAD_PARAMETER);
}
if (!acpi_gbl_RSDP) {
/* Get the RSDP */
status = acpi_os_get_root_pointer (flags, &physical_address);
if (ACPI_FAILURE (status)) {
ACPI_DEBUG_PRINT ((ACPI_DB_INFO, "RSDP not found\n"));
return_ACPI_STATUS (AE_NO_ACPI_TABLES);
}
/* Map and validate the RSDP */
if ((flags & ACPI_MEMORY_MODE) == ACPI_LOGICAL_ADDRESSING) {
status = acpi_os_map_memory (physical_address, sizeof (RSDP_DESCRIPTOR),
(void **) &acpi_gbl_RSDP);
if (ACPI_FAILURE (status)) {
return_ACPI_STATUS (status);
}
}
else {
acpi_gbl_RSDP = (void *) (NATIVE_UINT) physical_address;
}
/*
* The signature and checksum must both be correct
*/
if (STRNCMP ((NATIVE_CHAR *) acpi_gbl_RSDP, RSDP_SIG, sizeof (RSDP_SIG)-1) != 0) {
/* Nope, BAD Signature */
status = AE_BAD_SIGNATURE;
goto cleanup;
}
if (acpi_tb_checksum (acpi_gbl_RSDP, RSDP_CHECKSUM_LENGTH) != 0) {
/* Nope, BAD Checksum */
status = AE_BAD_CHECKSUM;
goto cleanup;
}
}
ACPI_DEBUG_PRINT ((ACPI_DB_INFO,
"RSDP located at %p, RSDT physical=%8.8X%8.8X \n",
acpi_gbl_RSDP, HIDWORD(acpi_gbl_RSDP->rsdt_physical_address),
LODWORD(acpi_gbl_RSDP->rsdt_physical_address)));
/* Get the RSDT and validate it */
physical_address = acpi_tb_get_rsdt_address ();
status = acpi_tb_get_table_pointer (physical_address, flags, &rsdt_size, &rsdt_ptr);
if (ACPI_FAILURE (status)) {
return_ACPI_STATUS (status);
}
status = acpi_tb_validate_rsdt (rsdt_ptr);
if (ACPI_FAILURE (status)) {
goto cleanup;
}
/* Get the number of table pointers within the RSDT */
table_count = acpi_tb_get_table_count (acpi_gbl_RSDP, rsdt_ptr);
/*
* Search the RSDT/XSDT for the correct instance of the
* requested table
*/
for (i = 0, j = 0; i < table_count; i++) {
/* Get the next table pointer */
if (acpi_gbl_RSDP->revision < 2) {
physical_address = ((RSDT_DESCRIPTOR *) rsdt_ptr)->table_offset_entry[i];
}
else {
physical_address = (ACPI_PHYSICAL_ADDRESS)
ACPI_GET_ADDRESS (((xsdt_descriptor *) rsdt_ptr)->table_offset_entry[i]);
}
/* Get addressibility if necessary */
status = acpi_tb_get_table_pointer (physical_address, flags, &table_size, &table_ptr);
if (ACPI_FAILURE (status)) {
goto cleanup;
}
/* Compare table signatures and table instance */
if (!STRNCMP ((char *) table_ptr, signature, STRLEN (signature))) {
/* An instance of the table was found */
j++;
if (j >= instance) {
/* Found the correct instance */
*table_pointer = table_ptr;
goto cleanup;
}
}
/* Delete table mapping if using virtual addressing */
if ((table_size) &&
((flags & ACPI_MEMORY_MODE) == ACPI_LOGICAL_ADDRESSING)) {
acpi_os_unmap_memory (table_ptr, table_size);
}
}
/* Did not find the table */
status = AE_NOT_EXIST;
cleanup:
if (rsdt_size) {
acpi_os_unmap_memory (rsdt_ptr, rsdt_size);
}
return_ACPI_STATUS (status);
}
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