/** @file
  RSDP table parser

  Copyright (c) 2016 - 2018, ARM Limited. All rights reserved.
  This program and the accompanying materials
  are licensed and made available under the terms and conditions of the BSD License
  which accompanies this distribution.  The full text of the license may be found at
  http://opensource.org/licenses/bsd-license.php

  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.

  @par Reference(s):
    - ACPI 6.2 Specification - Errata A, September 2017
**/

#include <Library/UefiLib.h>
#include "AcpiParser.h"
#include "AcpiTableParser.h"

// Local Variables
STATIC CONST UINT64* XsdtAddress;

/**
  This function validates the RSDT Address.

  @param [in] Ptr     Pointer to the start of the field data.
  @param [in] Context Pointer to context specific information e.g. this
                      could be a pointer to the ACPI table header.
**/
STATIC
VOID
EFIAPI
ValidateRsdtAddress (
  IN UINT8* Ptr,
  IN VOID*  Context
  );

/**
  This function validates the XSDT Address.

  @param [in] Ptr     Pointer to the start of the field data.
  @param [in] Context Pointer to context specific information e.g. this
                      could be a pointer to the ACPI table header.
**/
STATIC
VOID
EFIAPI
ValidateXsdtAddress (
  IN UINT8* Ptr,
  IN VOID*  Context
  );

/**
  An array describing the ACPI RSDP Table.
**/
STATIC CONST ACPI_PARSER RsdpParser[] = {
  {L"Signature", 8, 0, NULL, Dump8Chars, NULL, NULL, NULL},
  {L"Checksum", 1, 8, L"0x%x", NULL, NULL, NULL, NULL},
  {L"Oem ID", 6, 9, NULL, Dump6Chars, NULL, NULL, NULL},
  {L"Revision", 1, 15, L"%d", NULL, NULL, NULL, NULL},
  {L"RSDT Address", 4, 16, L"0x%x", NULL, NULL, ValidateRsdtAddress, NULL},
  {L"Length", 4, 20, L"%d", NULL, NULL, NULL, NULL},
  {L"XSDT Address", 8, 24, L"0x%lx", NULL, (VOID**)&XsdtAddress,
   ValidateXsdtAddress, NULL},
  {L"Extended Checksum", 1, 32, L"0x%x", NULL, NULL, NULL, NULL},
  {L"Reserved", 3, 33, L"%x %x %x", Dump3Chars, NULL, NULL, NULL}
};

/**
  This function validates the RSDT Address.

  @param [in] Ptr     Pointer to the start of the field data.
  @param [in] Context Pointer to context specific information e.g. this
                      could be a pointer to the ACPI table header.
**/
STATIC
VOID
EFIAPI
ValidateRsdtAddress (
  IN UINT8* Ptr,
  IN VOID*  Context
  )
{
#if defined(MDE_CPU_ARM) || defined (MDE_CPU_AARCH64)
  // Reference: Server Base Boot Requirements System Software on ARM Platforms
  // Section: 4.2.1.1 RSDP
  // Root System Description Pointer (RSDP), ACPI ? 5.2.5.
  //   - Within the RSDP, the RsdtAddress field must be null (zero) and the
  //     XsdtAddresss MUST be a valid, non-null, 64-bit value.
  UINT32 RsdtAddr;

  RsdtAddr = *(UINT32*)Ptr;

  if (RsdtAddr != 0) {
    IncrementErrorCount ();
    Print (
      L"\nERROR: Rsdt Address = 0x%p. This must be NULL on ARM Platforms.",
      RsdtAddr
      );
  }
#endif
}

/**
  This function validates the XSDT Address.

  @param [in] Ptr     Pointer to the start of the field data.
  @param [in] Context Pointer to context specific information e.g. this
                      could be a pointer to the ACPI table header.
**/
STATIC
VOID
EFIAPI
ValidateXsdtAddress (
  IN UINT8* Ptr,
  IN VOID*  Context
  )
{
#if defined(MDE_CPU_ARM) || defined (MDE_CPU_AARCH64)
  // Reference: Server Base Boot Requirements System Software on ARM Platforms
  // Section: 4.2.1.1 RSDP
  // Root System Description Pointer (RSDP), ACPI ? 5.2.5.
  //   - Within the RSDP, the RsdtAddress field must be null (zero) and the
  //     XsdtAddresss MUST be a valid, non-null, 64-bit value.
  UINT64 XsdtAddr;

  XsdtAddr = *(UINT64*)Ptr;

  if (XsdtAddr == 0) {
    IncrementErrorCount ();
    Print (
      L"\nERROR: Xsdt Address = 0x%p. This must not be NULL on ARM Platforms.",
      XsdtAddr
      );
  }
#endif
}

/**
  This function parses the ACPI RSDP table.

  This function invokes the parser for the XSDT table.
  * Note - This function does not support parsing of RSDT table.

  This function also performs a RAW dump of the ACPI table and
  validates the checksum.

  @param [in] Trace              If TRUE, trace the ACPI fields.
  @param [in] Ptr                Pointer to the start of the buffer.
  @param [in] AcpiTableLength    Length of the ACPI table.
  @param [in] AcpiTableRevision  Revision of the ACPI table.
**/
VOID
EFIAPI
ParseAcpiRsdp (
  IN BOOLEAN Trace,
  IN UINT8*  Ptr,
  IN UINT32  AcpiTableLength,
  IN UINT8   AcpiTableRevision
  )
{
  if (Trace) {
    DumpRaw (Ptr, AcpiTableLength);
    VerifyChecksum (TRUE, Ptr, AcpiTableLength);
  }

  ParseAcpi (Trace, 0, "RSDP", Ptr, AcpiTableLength, PARSER_PARAMS (RsdpParser));

  // This code currently supports parsing of XSDT table only
  // and does not parse the RSDT table. Platforms provide the
  // RSDT to enable compatibility with ACPI 1.0 operating systems.
  // Therefore the RSDT should not be used on ARM platforms.
  if ((*XsdtAddress) == 0) {
    IncrementErrorCount ();
    Print (L"ERROR: XSDT Pointer is not set.\n");
    return;
  }

  ProcessAcpiTable ((UINT8*)(UINTN)(*XsdtAddress));
}