/******************************************************************************
*
* Module Name: tbxfroot - Find the root ACPI table (RSDT)
*
*****************************************************************************/
/*
* Copyright (C) 2000 - 2018, Intel Corp.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions, and the following disclaimer,
* without modification.
* 2. Redistributions in binary form must reproduce at minimum a disclaimer
* substantially similar to the "NO WARRANTY" disclaimer below
* ("Disclaimer") and any redistribution must be conditioned upon
* including a substantially similar Disclaimer requirement for further
* binary redistribution.
* 3. Neither the names of the above-listed copyright holders nor the names
* of any contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* Alternatively, this software may be distributed under the terms of the
* GNU General Public License ("GPL") version 2 as published by the Free
* Software Foundation.
*
* NO WARRANTY
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGES.
*/
#include "acpi.h"
#include "accommon.h"
#include "actables.h"
#define _COMPONENT ACPI_TABLES
ACPI_MODULE_NAME ("tbxfroot")
/*******************************************************************************
*
* FUNCTION: AcpiTbGetRsdpLength
*
* PARAMETERS: Rsdp - Pointer to RSDP
*
* RETURN: Table length
*
* DESCRIPTION: Get the length of the RSDP
*
******************************************************************************/
UINT32
AcpiTbGetRsdpLength (
ACPI_TABLE_RSDP *Rsdp)
{
if (!ACPI_VALIDATE_RSDP_SIG (Rsdp->Signature))
{
/* BAD Signature */
return (0);
}
/* "Length" field is available if table version >= 2 */
if (Rsdp->Revision >= 2)
{
return (Rsdp->Length);
}
else
{
return (ACPI_RSDP_CHECKSUM_LENGTH);
}
}
/*******************************************************************************
*
* FUNCTION: AcpiTbValidateRsdp
*
* PARAMETERS: Rsdp - Pointer to unvalidated RSDP
*
* RETURN: Status
*
* DESCRIPTION: Validate the RSDP (ptr)
*
******************************************************************************/
ACPI_STATUS
AcpiTbValidateRsdp (
ACPI_TABLE_RSDP *Rsdp)
{
/*
* The signature and checksum must both be correct
*
* Note: Sometimes there exists more than one RSDP in memory; the valid
* RSDP has a valid checksum, all others have an invalid checksum.
*/
if (!ACPI_VALIDATE_RSDP_SIG (Rsdp->Signature))
{
/* Nope, BAD Signature */
return (AE_BAD_SIGNATURE);
}
/* Check the standard checksum */
if (AcpiTbChecksum ((UINT8 *) Rsdp, ACPI_RSDP_CHECKSUM_LENGTH) != 0)
{
return (AE_BAD_CHECKSUM);
}
/* Check extended checksum if table version >= 2 */
if ((Rsdp->Revision >= 2) &&
(AcpiTbChecksum ((UINT8 *) Rsdp, ACPI_RSDP_XCHECKSUM_LENGTH) != 0))
{
return (AE_BAD_CHECKSUM);
}
return (AE_OK);
}
/*******************************************************************************
*
* FUNCTION: AcpiFindRootPointer
*
* PARAMETERS: TableAddress - Where the table pointer is returned
*
* RETURN: Status, RSDP physical address
*
* DESCRIPTION: Search lower 1Mbyte of memory for the root system descriptor
* pointer structure. If it is found, set *RSDP to point to it.
*
* NOTE1: The RSDP must be either in the first 1K of the Extended
* BIOS Data Area or between E0000 and FFFFF (From ACPI Spec.)
* Only a 32-bit physical address is necessary.
*
* NOTE2: This function is always available, regardless of the
* initialization state of the rest of ACPI.
*
******************************************************************************/
ACPI_STATUS ACPI_INIT_FUNCTION
AcpiFindRootPointer (
ACPI_PHYSICAL_ADDRESS *TableAddress)
{
UINT8 *TablePtr;
UINT8 *MemRover;
UINT32 PhysicalAddress;
ACPI_FUNCTION_TRACE (AcpiFindRootPointer);
/* 1a) Get the location of the Extended BIOS Data Area (EBDA) */
TablePtr = AcpiOsMapMemory (
(ACPI_PHYSICAL_ADDRESS) ACPI_EBDA_PTR_LOCATION,
ACPI_EBDA_PTR_LENGTH);
if (!TablePtr)
{
ACPI_ERROR ((AE_INFO,
"Could not map memory at 0x%8.8X for length %u",
ACPI_EBDA_PTR_LOCATION, ACPI_EBDA_PTR_LENGTH));
return_ACPI_STATUS (AE_NO_MEMORY);
}
ACPI_MOVE_16_TO_32 (&PhysicalAddress, TablePtr);
/* Convert segment part to physical address */
PhysicalAddress <<= 4;
AcpiOsUnmapMemory (TablePtr, ACPI_EBDA_PTR_LENGTH);
/* EBDA present? */
if (PhysicalAddress > 0x400)
{
/*
* 1b) Search EBDA paragraphs (EBDA is required to be a
* minimum of 1K length)
*/
TablePtr = AcpiOsMapMemory (
(ACPI_PHYSICAL_ADDRESS) PhysicalAddress,
ACPI_EBDA_WINDOW_SIZE);
if (!TablePtr)
{
ACPI_ERROR ((AE_INFO,
"Could not map memory at 0x%8.8X for length %u",
PhysicalAddress, ACPI_EBDA_WINDOW_SIZE));
return_ACPI_STATUS (AE_NO_MEMORY);
}
MemRover = AcpiTbScanMemoryForRsdp (
TablePtr, ACPI_EBDA_WINDOW_SIZE);
AcpiOsUnmapMemory (TablePtr, ACPI_EBDA_WINDOW_SIZE);
if (MemRover)
{
/* Return the physical address */
PhysicalAddress +=
(UINT32) ACPI_PTR_DIFF (MemRover, TablePtr);
*TableAddress = (ACPI_PHYSICAL_ADDRESS) PhysicalAddress;
return_ACPI_STATUS (AE_OK);
}
}
/*
* 2) Search upper memory: 16-byte boundaries in E0000h-FFFFFh
*/
TablePtr = AcpiOsMapMemory (
(ACPI_PHYSICAL_ADDRESS) ACPI_HI_RSDP_WINDOW_BASE,
ACPI_HI_RSDP_WINDOW_SIZE);
if (!TablePtr)
{
ACPI_ERROR ((AE_INFO,
"Could not map memory at 0x%8.8X for length %u",
ACPI_HI_RSDP_WINDOW_BASE, ACPI_HI_RSDP_WINDOW_SIZE));
return_ACPI_STATUS (AE_NO_MEMORY);
}
MemRover = AcpiTbScanMemoryForRsdp (
TablePtr, ACPI_HI_RSDP_WINDOW_SIZE);
AcpiOsUnmapMemory (TablePtr, ACPI_HI_RSDP_WINDOW_SIZE);
if (MemRover)
{
/* Return the physical address */
PhysicalAddress = (UINT32)
(ACPI_HI_RSDP_WINDOW_BASE + ACPI_PTR_DIFF (MemRover, TablePtr));
*TableAddress = (ACPI_PHYSICAL_ADDRESS) PhysicalAddress;
return_ACPI_STATUS (AE_OK);
}
/* A valid RSDP was not found */
ACPI_BIOS_ERROR ((AE_INFO, "A valid RSDP was not found"));
return_ACPI_STATUS (AE_NOT_FOUND);
}
ACPI_EXPORT_SYMBOL_INIT (AcpiFindRootPointer)
/*******************************************************************************
*
* FUNCTION: AcpiTbScanMemoryForRsdp
*
* PARAMETERS: StartAddress - 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
*
******************************************************************************/
UINT8 *
AcpiTbScanMemoryForRsdp (
UINT8 *StartAddress,
UINT32 Length)
{
ACPI_STATUS Status;
UINT8 *MemRover;
UINT8 *EndAddress;
ACPI_FUNCTION_TRACE (TbScanMemoryForRsdp);
EndAddress = StartAddress + Length;
/* Search from given start address for the requested length */
for (MemRover = StartAddress; MemRover < EndAddress;
MemRover += ACPI_RSDP_SCAN_STEP)
{
/* The RSDP signature and checksum must both be correct */
Status = AcpiTbValidateRsdp (
ACPI_CAST_PTR (ACPI_TABLE_RSDP, MemRover));
if (ACPI_SUCCESS (Status))
{
/* Sig and checksum valid, we have found a real RSDP */
ACPI_DEBUG_PRINT ((ACPI_DB_INFO,
"RSDP located at physical address %p\n", MemRover));
return_PTR (MemRover);
}
/* No sig match or bad checksum, keep searching */
}
/* Searched entire block, no RSDP was found */
ACPI_DEBUG_PRINT ((ACPI_DB_INFO,
"Searched entire block from %p, valid RSDP was not found\n",
StartAddress));
return_PTR (NULL);
}