/** @file
  Sample ACPI Platform Driver

  Copyright (c) 2008 - 2018, Intel Corporation. All rights reserved.<BR>
  SPDX-License-Identifier: BSD-2-Clause-Patent

**/

#include <PiDxe.h>

#include <Protocol/AcpiTable.h>
#include <Protocol/FirmwareVolume2.h>

#include <Library/BaseLib.h>
#include <Library/UefiBootServicesTableLib.h>
#include <Library/DebugLib.h>
#include <Library/PcdLib.h>

#include <IndustryStandard/Acpi.h>

/**
  Locate the first instance of a protocol.  If the protocol requested is an
  FV protocol, then it will return the first FV that contains the ACPI table
  storage file.

  @param  Instance      Return pointer to the first instance of the protocol

  @return EFI_SUCCESS           The function completed successfully.
  @return EFI_NOT_FOUND         The protocol could not be located.
  @return EFI_OUT_OF_RESOURCES  There are not enough resources to find the protocol.

**/
EFI_STATUS
LocateFvInstanceWithTables (
  OUT EFI_FIRMWARE_VOLUME2_PROTOCOL **Instance
  )
{
  EFI_STATUS                    Status;
  EFI_HANDLE                    *HandleBuffer;
  UINTN                         NumberOfHandles;
  EFI_FV_FILETYPE               FileType;
  UINT32                        FvStatus;
  EFI_FV_FILE_ATTRIBUTES        Attributes;
  UINTN                         Size;
  UINTN                         Index;
  EFI_FIRMWARE_VOLUME2_PROTOCOL *FvInstance;

  FvStatus = 0;

  //
  // Locate protocol.
  //
  Status = gBS->LocateHandleBuffer (
                   ByProtocol,
                   &gEfiFirmwareVolume2ProtocolGuid,
                   NULL,
                   &NumberOfHandles,
                   &HandleBuffer
                   );
  if (EFI_ERROR (Status)) {
    //
    // Defined errors at this time are not found and out of resources.
    //
    return Status;
  }



  //
  // Looking for FV with ACPI storage file
  //

  for (Index = 0; Index < NumberOfHandles; Index++) {
    //
    // Get the protocol on this handle
    // This should not fail because of LocateHandleBuffer
    //
    Status = gBS->HandleProtocol (
                     HandleBuffer[Index],
                     &gEfiFirmwareVolume2ProtocolGuid,
                     (VOID**) &FvInstance
                     );
    ASSERT_EFI_ERROR (Status);

    //
    // See if it has the ACPI storage file
    //
    Status = FvInstance->ReadFile (
                           FvInstance,
                           (EFI_GUID*)PcdGetPtr (PcdAcpiTableStorageFile),
                           NULL,
                           &Size,
                           &FileType,
                           &Attributes,
                           &FvStatus
                           );

    //
    // If we found it, then we are done
    //
    if (Status == EFI_SUCCESS) {
      *Instance = FvInstance;
      break;
    }
  }

  //
  // Our exit status is determined by the success of the previous operations
  // If the protocol was found, Instance already points to it.
  //

  //
  // Free any allocated buffers
  //
  gBS->FreePool (HandleBuffer);

  return Status;
}


/**
  This function calculates and updates an UINT8 checksum.

  @param  Buffer          Pointer to buffer to checksum
  @param  Size            Number of bytes to checksum

**/
VOID
AcpiPlatformChecksum (
  IN UINT8      *Buffer,
  IN UINTN      Size
  )
{
  UINTN ChecksumOffset;

  ChecksumOffset = OFFSET_OF (EFI_ACPI_DESCRIPTION_HEADER, Checksum);

  //
  // Set checksum to 0 first
  //
  Buffer[ChecksumOffset] = 0;

  //
  // Update checksum value
  //
  Buffer[ChecksumOffset] = CalculateCheckSum8(Buffer, Size);
}


/**
  Entrypoint of Acpi Platform driver.

  @param  ImageHandle
  @param  SystemTable

  @return EFI_SUCCESS
  @return EFI_LOAD_ERROR
  @return EFI_OUT_OF_RESOURCES

**/
EFI_STATUS
EFIAPI
AcpiPlatformEntryPoint (
  IN EFI_HANDLE         ImageHandle,
  IN EFI_SYSTEM_TABLE   *SystemTable
  )
{
  EFI_STATUS                     Status;
  EFI_ACPI_TABLE_PROTOCOL        *AcpiTable;
  EFI_FIRMWARE_VOLUME2_PROTOCOL  *FwVol;
  INTN                           Instance;
  EFI_ACPI_COMMON_HEADER         *CurrentTable;
  UINTN                          TableHandle;
  UINT32                         FvStatus;
  UINTN                          TableSize;
  UINTN                          Size;

  Instance     = 0;
  CurrentTable = NULL;
  TableHandle  = 0;

  //
  // Find the AcpiTable protocol
  //
  Status = gBS->LocateProtocol (&gEfiAcpiTableProtocolGuid, NULL, (VOID**)&AcpiTable);
  if (EFI_ERROR (Status)) {
    return EFI_ABORTED;
  }

  //
  // Locate the firmware volume protocol
  //
  Status = LocateFvInstanceWithTables (&FwVol);
  if (EFI_ERROR (Status)) {
    return EFI_ABORTED;
  }
  //
  // Read tables from the storage file.
  //
  while (Status == EFI_SUCCESS) {

    Status = FwVol->ReadSection (
                      FwVol,
                      (EFI_GUID*)PcdGetPtr (PcdAcpiTableStorageFile),
                      EFI_SECTION_RAW,
                      Instance,
                      (VOID**) &CurrentTable,
                      &Size,
                      &FvStatus
                      );
    if (!EFI_ERROR(Status)) {
      //
      // Add the table
      //
      TableHandle = 0;

      TableSize = ((EFI_ACPI_DESCRIPTION_HEADER *) CurrentTable)->Length;
      ASSERT (Size >= TableSize);

      //
      // Checksum ACPI table
      //
      AcpiPlatformChecksum ((UINT8*)CurrentTable, TableSize);

      //
      // Install ACPI table
      //
      Status = AcpiTable->InstallAcpiTable (
                            AcpiTable,
                            CurrentTable,
                            TableSize,
                            &TableHandle
                            );

      //
      // Free memory allocated by ReadSection
      //
      gBS->FreePool (CurrentTable);

      if (EFI_ERROR(Status)) {
        return EFI_ABORTED;
      }

      //
      // Increment the instance
      //
      Instance++;
      CurrentTable = NULL;
    }
  }

  //
  // The driver does not require to be kept loaded.
  //
  return EFI_REQUEST_UNLOAD_IMAGE;
}