audk/Vlv2TbltDevicePkg/Metronome/LegacyMetronome.c

/** @file

  Copyright (c) 2004  - 2014, Intel Corporation. All rights reserved.<BR>
                                                                                   
  SPDX-License-Identifier: BSD-2-Clause-Patent

                                                                                   

Module Name:


  LegacyMetronome.c

Abstract:

  This contains the installation function for the driver.

--*/

#include "LegacyMetronome.h"

//
// Handle for the Metronome Architectural Protocol instance produced by this driver
//
EFI_HANDLE                  mMetronomeHandle = NULL;

//
// The Metronome Architectural Protocol instance produced by this driver
//
EFI_METRONOME_ARCH_PROTOCOL mMetronome = {
  WaitForTick,
  TICK_PERIOD
};

//
// The CPU I/O Protocol used to access system hardware
//
EFI_CPU_IO_PROTOCOL         *mCpuIo = NULL;

//
// Worker Functions
//

/**
  Write an 8 bit value to an I/O port and save it to the S3 script

  @param Port  IO Port
  @param Data  Data in IO Port

  @retval None.

**/
VOID
ScriptWriteIo8 (
  UINT16  Port,
  UINT8   Data
  )
{
  mCpuIo->Io.Write (
               mCpuIo,
               EfiCpuIoWidthUint8,
               Port,
               1,
               &Data
               );

}

/**

  Read the refresh bit from the REFRESH_PORT

  @param None.

  @retval Refresh bit.

**/
UINT8
ReadRefresh (
  VOID
  )
{
  UINT8 Data;

  mCpuIo->Io.Read (
               mCpuIo,
               EfiCpuIoWidthUint8,
               REFRESH_PORT,
               1,
               &Data
               );
  return (UINT8) (Data & REFRESH_ON);
}

/**

  Waits for the TickNumber of ticks from a known platform time source.

  @param This                Pointer to the protocol instance.
  @param TickNumber          Tick Number to be waited


  @retval EFI_SUCCESS         If number of ticks occurred.
  @retval EFI_NOT_FOUND       Could not locate CPU IO protocol

**/
EFI_STATUS
EFIAPI
WaitForTick (
  IN EFI_METRONOME_ARCH_PROTOCOL  *This,
  IN UINT32                       TickNumber
  )
{
  //
  // Wait for TickNumber toggles of the Refresh bit
  //
  for (; TickNumber != 0x00; TickNumber--) {
    while (ReadRefresh () == REFRESH_ON)
      ;
    while (ReadRefresh () == REFRESH_OFF)
      ;
  }

  return EFI_SUCCESS;
}

//
// Driver Entry Point
//
/**
  Install the LegacyMetronome driver.  Loads a Metronome Arch Protocol based
  on the Port 61 timer.

  @param ImageHandle      Handle for the image of this driver
  @param SystemTable      Pointer to the EFI System Table

  @retval EFI_SUCCESS     Metronome Architectural Protocol Installed

**/
EFI_STATUS
EFIAPI
InstallLegacyMetronome (
  IN EFI_HANDLE        ImageHandle,
  IN EFI_SYSTEM_TABLE  *SystemTable
  )
{
  EFI_STATUS  Status;

  //
  // Make sure the Metronome Architectural Protocol is not already installed in the system
  //
  ASSERT_PROTOCOL_ALREADY_INSTALLED (NULL, &gEfiMetronomeArchProtocolGuid);

  //
  // Get the CPU I/O Protocol that this driver requires
  // If the CPU I/O Protocol is not found, then ASSERT because the dependency expression
  // should guarantee that it is present in the handle database.
  //
  Status = gBS->LocateProtocol (
                  &gEfiCpuIoProtocolGuid,
                  NULL,
                  (void **)&mCpuIo
                  );
  ASSERT_EFI_ERROR (Status);

  //
  // Program port 61 timer 1 as refresh timer. We could use ACPI timer in the
  // future.
  //
  ScriptWriteIo8 (TIMER1_CONTROL_PORT, LOAD_COUNTER1_LSB);
  ScriptWriteIo8 (TIMER1_COUNT_PORT, COUNTER1_COUNT);

  //
  // Install on a new handle
  //
  Status = gBS->InstallMultipleProtocolInterfaces (
                  &mMetronomeHandle,
                  &gEfiMetronomeArchProtocolGuid,
                  &mMetronome,
                  NULL
                  );
  ASSERT_EFI_ERROR (Status);

  return Status;
}