/****************************************************************************** * * Module Name: tbxfroot - Find the root ACPI table (RSDT) * *****************************************************************************/ /* * Copyright (C) 2000 - 2011, 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. */ #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); }