/******************************************************************************
*
* Module Name: tbxfroot - Find the root ACPI table (RSDT)
*
*****************************************************************************/
/******************************************************************************
*
* 1. Copyright Notice
*
* Some or all of this work - Copyright (c) 1999 - 2011, Intel Corp.
* All rights reserved.
*
* 2. License
*
* 2.1. This is your license from Intel Corp. under its intellectual property
* rights. You may have additional license terms from the party that provided
* you this software, covering your right to use that party's intellectual
* property rights.
*
* 2.2. Intel grants, free of charge, to any person ("Licensee") obtaining a
* copy of the source code appearing in this file ("Covered Code") an
* irrevocable, perpetual, worldwide license under Intel's copyrights in the
* base code distributed originally by Intel ("Original Intel Code") to copy,
* make derivatives, distribute, use and display any portion of the Covered
* Code in any form, with the right to sublicense such rights; and
*
* 2.3. Intel grants Licensee a non-exclusive and non-transferable patent
* license (with the right to sublicense), under only those claims of Intel
* patents that are infringed by the Original Intel Code, to make, use, sell,
* offer to sell, and import the Covered Code and derivative works thereof
* solely to the minimum extent necessary to exercise the above copyright
* license, and in no event shall the patent license extend to any additions
* to or modifications of the Original Intel Code. No other license or right
* is granted directly or by implication, estoppel or otherwise;
*
* The above copyright and patent license is granted only if the following
* conditions are met:
*
* 3. Conditions
*
* 3.1. Redistribution of Source with Rights to Further Distribute Source.
* Redistribution of source code of any substantial portion of the Covered
* Code or modification with rights to further distribute source must include
* the above Copyright Notice, the above License, this list of Conditions,
* and the following Disclaimer and Export Compliance provision. In addition,
* Licensee must cause all Covered Code to which Licensee contributes to
* contain a file documenting the changes Licensee made to create that Covered
* Code and the date of any change. Licensee must include in that file the
* documentation of any changes made by any predecessor Licensee. Licensee
* must include a prominent statement that the modification is derived,
* directly or indirectly, from Original Intel Code.
*
* 3.2. Redistribution of Source with no Rights to Further Distribute Source.
* Redistribution of source code of any substantial portion of the Covered
* Code or modification without rights to further distribute source must
* include the following Disclaimer and Export Compliance provision in the
* documentation and/or other materials provided with distribution. In
* addition, Licensee may not authorize further sublicense of source of any
* portion of the Covered Code, and must include terms to the effect that the
* license from Licensee to its licensee is limited to the intellectual
* property embodied in the software Licensee provides to its licensee, and
* not to intellectual property embodied in modifications its licensee may
* make.
*
* 3.3. Redistribution of Executable. Redistribution in executable form of any
* substantial portion of the Covered Code or modification must reproduce the
* above Copyright Notice, and the following Disclaimer and Export Compliance
* provision in the documentation and/or other materials provided with the
* distribution.
*
* 3.4. Intel retains all right, title, and interest in and to the Original
* Intel Code.
*
* 3.5. Neither the name Intel nor any other trademark owned or controlled by
* Intel shall be used in advertising or otherwise to promote the sale, use or
* other dealings in products derived from or relating to the Covered Code
* without prior written authorization from Intel.
*
* 4. Disclaimer and Export Compliance
*
* 4.1. INTEL MAKES NO WARRANTY OF ANY KIND REGARDING ANY SOFTWARE PROVIDED
* HERE. ANY SOFTWARE ORIGINATING FROM INTEL OR DERIVED FROM INTEL SOFTWARE
* IS PROVIDED "AS IS," AND INTEL WILL NOT PROVIDE ANY SUPPORT, ASSISTANCE,
* INSTALLATION, TRAINING OR OTHER SERVICES. INTEL WILL NOT PROVIDE ANY
* UPDATES, ENHANCEMENTS OR EXTENSIONS. INTEL SPECIFICALLY DISCLAIMS ANY
* IMPLIED WARRANTIES OF MERCHANTABILITY, NONINFRINGEMENT AND FITNESS FOR A
* PARTICULAR PURPOSE.
*
* 4.2. IN NO EVENT SHALL INTEL HAVE ANY LIABILITY TO LICENSEE, ITS LICENSEES
* OR ANY OTHER THIRD PARTY, FOR ANY LOST PROFITS, LOST DATA, LOSS OF USE OR
* COSTS OF PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES, OR FOR ANY INDIRECT,
* SPECIAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THIS AGREEMENT, UNDER ANY
* CAUSE OF ACTION OR THEORY OF LIABILITY, AND IRRESPECTIVE OF WHETHER INTEL
* HAS ADVANCE NOTICE OF THE POSSIBILITY OF SUCH DAMAGES. THESE LIMITATIONS
* SHALL APPLY NOTWITHSTANDING THE FAILURE OF THE ESSENTIAL PURPOSE OF ANY
* LIMITED REMEDY.
*
* 4.3. Licensee shall not export, either directly or indirectly, any of this
* software or system incorporating such software without first obtaining any
* required license or other approval from the U. S. Department of Commerce or
* any other agency or department of the United States Government. In the
* event Licensee exports any such software from the United States or
* re-exports any such software from a foreign destination, Licensee shall
* ensure that the distribution and export/re-export of the software is in
* compliance with all laws, regulations, orders, or other restrictions of the
* U.S. Export Administration Regulations. Licensee agrees that neither it nor
* any of its subsidiaries will export/re-export any technical data, process,
* software, or service, directly or indirectly, to any country for which the
* United States government or any agency thereof requires an export license,
* other governmental approval, or letter of assurance, without first obtaining
* such license, approval or letter.
*
*****************************************************************************/
#define __TBXFROOT_C__
#include "acpi.h"
#include "accommon.h"
#include "actables.h"
#define _COMPONENT ACPI_TABLES
ACPI_MODULE_NAME ("tbxfroot")
/* Local prototypes */
static UINT8 *
AcpiTbScanMemoryForRsdp (
UINT8 *StartAddress,
UINT32 Length);
static ACPI_STATUS
AcpiTbValidateRsdp (
ACPI_TABLE_RSDP *Rsdp);
/*******************************************************************************
*
* FUNCTION: AcpiTbValidateRsdp
*
* PARAMETERS: Rsdp - Pointer to unvalidated RSDP
*
* RETURN: Status
*
* DESCRIPTION: Validate the RSDP (ptr)
*
******************************************************************************/
static ACPI_STATUS
AcpiTbValidateRsdp (
ACPI_TABLE_RSDP *Rsdp)
{
ACPI_FUNCTION_ENTRY ();
/*
* 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_STRNCMP ((char *) Rsdp, ACPI_SIG_RSDP,
sizeof (ACPI_SIG_RSDP)-1) != 0)
{
/* 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
AcpiFindRootPointer (
ACPI_SIZE *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 = 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 = PhysicalAddress;
return_ACPI_STATUS (AE_OK);
}
/* A valid RSDP was not found */
ACPI_ERROR ((AE_INFO, "A valid RSDP was not found"));
return_ACPI_STATUS (AE_NOT_FOUND);
}
ACPI_EXPORT_SYMBOL (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
*
******************************************************************************/
static 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);
}