mirror_edk2/IntelFrameworkModulePkg/Universal/LegacyRegionDxe/LegacyRegion.c

/** @file
  Produces the Legacy Region Protocol.

  This generic implementation of the Legacy Region Protocol does not actually
  perform any lock/unlock operations.  This module may be used on platforms
  that do not provide HW locking of the legacy memory regions.  It can also
  be used as a template driver for implementing the Legacy Region Protocol on
  a platform that does support HW locking of the legacy memory regions.

Copyright (c) 2009 - 2018, Intel Corporation. All rights reserved.<BR>
SPDX-License-Identifier: BSD-2-Clause-Patent

**/

#include <PiDxe.h>
#include <Protocol/LegacyRegion.h>
#include <Library/DebugLib.h>
#include <Library/UefiBootServicesTableLib.h>

/**
  Sets hardware to decode or not decode a region.

  @param  This                  Indicates the EFI_LEGACY_REGION_PROTOCOL instance
  @param  Start                 Start of region to decode.
  @param  Length                Size in bytes of the region.
  @param  On                    Decode/nondecode flag.

  @retval EFI_SUCCESS           Decode range successfully changed.

**/
EFI_STATUS
EFIAPI
LegacyRegionDecode (
  IN EFI_LEGACY_REGION_PROTOCOL  *This,
  IN UINT32                      Start,
  IN UINT32                      Length,
  IN BOOLEAN                     *On
  )
{
  return EFI_SUCCESS;
}

/**
  Sets a region to read only.

  @param  This                  Indicates the EFI_LEGACY_REGION_PROTOCOL instance
  @param  Start                 Start of region to lock.
  @param  Length                Size in bytes of the region.
  @param  Granularity           Lock attribute affects this granularity in bytes.

  @retval EFI_SUCCESS           The region was made read only.

**/
EFI_STATUS
EFIAPI
LegacyRegionLock (
  IN  EFI_LEGACY_REGION_PROTOCOL  *This,
  IN  UINT32                      Start,
  IN  UINT32                      Length,
  OUT UINT32                      *Granularity OPTIONAL
  )
{
  return EFI_SUCCESS;
}

/**
  Sets a region to read only and ensures that flash is locked from being
  inadvertently modified.

  @param  This                  Indicates the EFI_LEGACY_REGION_PROTOCOL instance
  @param  Start                 Start of region to lock.
  @param  Length                Size in bytes of the region.
  @param  Granularity           Lock attribute affects this granularity in bytes.

  @retval EFI_SUCCESS           The region was made read only and flash is locked.

**/
EFI_STATUS
EFIAPI
LegacyRegionBootLock (
  IN  EFI_LEGACY_REGION_PROTOCOL  *This,
  IN  UINT32                      Start,
  IN  UINT32                      Length,
  OUT UINT32                      *Granularity OPTIONAL
  )
{
  return EFI_SUCCESS;
}

/**
  Sets a region to read-write.

  @param  This                  Indicates the EFI_LEGACY_REGION_PROTOCOL instance
  @param  Start                 Start of region to lock.
  @param  Length                Size in bytes of the region.
  @param  Granularity           Lock attribute affects this granularity in bytes.

  @retval EFI_SUCCESS           The region was successfully made read-write.

**/
EFI_STATUS
EFIAPI
LegacyRegionUnlock (
  IN  EFI_LEGACY_REGION_PROTOCOL  *This,
  IN  UINT32                      Start,
  IN  UINT32                      Length,
  OUT UINT32                      *Granularity OPTIONAL
  )
{
  return EFI_SUCCESS;
}

//
// Module global for the handle the Legacy Region Protocol is installed
//
EFI_HANDLE                  mLegacyRegionHandle = NULL;

//
// Module global for the Legacy Region Protocol instance that is installed onto
// mLegacyRegionHandle
//
EFI_LEGACY_REGION_PROTOCOL  mLegacyRegion = {
  LegacyRegionDecode,
  LegacyRegionLock,
  LegacyRegionBootLock,
  LegacyRegionUnlock
};

/**
  The user Entry Point for module LegacyRegionDxe.  The user code starts with this function.

  @param[in] ImageHandle    The firmware allocated handle for the EFI image.
  @param[in] SystemTable    A pointer to the EFI System Table.

  @retval EFI_SUCCESS       The entry point is executed successfully.
  @retval other             Some error occurs when executing this entry point.

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

  //
  // Make sure the Legacy Region Protocol is not already installed in the system
  //
  ASSERT_PROTOCOL_ALREADY_INSTALLED (NULL, &gEfiLegacyRegionProtocolGuid);

  //
  // Install the protocol on a new handle.
  //
  Status = gBS->InstallMultipleProtocolInterfaces (
                  &mLegacyRegionHandle,
                  &gEfiLegacyRegionProtocolGuid, &mLegacyRegion,
                  NULL
                  );
  ASSERT_EFI_ERROR (Status);

  return Status;
}