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/** @file
OVMF ACPI support
Copyright (C) 2021, Red Hat, Inc.
Copyright (c) 2008 - 2012, Intel Corporation. All rights reserved.<BR>
Copyright (c) 2012, Bei Guan <gbtju85@gmail.com>
SPDX-License-Identifier: BSD-2-Clause-Patent
**/
#include <Library/AcpiPlatformLib.h>
#include <Library/BaseLib.h>
#include <Library/DebugLib.h>
EFI_STATUS
EFIAPI
GetAcpiRsdpFromMemory (
IN UINTN StartAddress,
IN UINTN EndAddress,
OUT EFI_ACPI_2_0_ROOT_SYSTEM_DESCRIPTION_POINTER **RsdpPtr
)
{
EFI_ACPI_2_0_ROOT_SYSTEM_DESCRIPTION_POINTER *RsdpStructurePtr;
UINT8 *AcpiPtr;
UINT8 Sum;
for (AcpiPtr = (UINT8 *)StartAddress;
AcpiPtr < (UINT8 *)EndAddress;
AcpiPtr += 0x10)
{
RsdpStructurePtr = (EFI_ACPI_2_0_ROOT_SYSTEM_DESCRIPTION_POINTER *)
(UINTN)AcpiPtr;
if (!AsciiStrnCmp ((CHAR8 *)&RsdpStructurePtr->Signature, "RSD PTR ", 8)) {
//
// RSDP ACPI 1.0 checksum for 1.0/2.0/3.0 table.
// This is only the first 20 bytes of the structure
//
Sum = CalculateSum8 (
(CONST UINT8 *)RsdpStructurePtr,
sizeof (EFI_ACPI_1_0_ROOT_SYSTEM_DESCRIPTION_POINTER)
);
if (Sum != 0) {
return EFI_ABORTED;
}
if (RsdpStructurePtr->Revision >= 2) {
//
// RSDP ACPI 2.0/3.0 checksum, this is the entire table
//
Sum = CalculateSum8 (
(CONST UINT8 *)RsdpStructurePtr,
sizeof (EFI_ACPI_2_0_ROOT_SYSTEM_DESCRIPTION_POINTER)
);
if (Sum != 0) {
return EFI_ABORTED;
}
}
*RsdpPtr = RsdpStructurePtr;
return EFI_SUCCESS;
}
}
return EFI_NOT_FOUND;
}
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