diff --git a/MdePkg/Include/Library/BeIoLib.h b/MdePkg/Include/Library/BeIoLib.h
new file mode 100644
index 0000000000..5b2dc1a8e1
--- /dev/null
+++ b/MdePkg/Include/Library/BeIoLib.h
@@ -0,0 +1,376 @@
+/** @file
+  Provide byte-swapping services to access MMIO registers.
+
+Copyright (c) 2006 - 2012, Intel Corporation. All rights reserved.<BR>
+Copyright (c) 2017, AMD Incorporated. All rights reserved.<BR>
+Copyright (c) 2018, Linaro ltd. All rights reserved.<BR>
+
+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.
+
+**/
+
+#ifndef __BE_IO_LIB_H__
+#define __BE_IO_LIB_H__
+
+/**
+  Reads a 16-bit MMIO register of opposite endianness.
+
+  Reads the 16-bit MMIO register specified by Address.
+  The 16-bit read value is returned in reversed byte order.
+  This function must guarantee that all MMIO read and write
+  operations are serialized.
+
+  @param  Address The MMIO register to read.
+
+  @return The value read.
+
+**/
+UINT16
+EFIAPI
+BeMmioRead16 (
+  IN      UINTN                     Address
+  );
+
+/**
+  Writes a 16-bit MMIO register of opposite endianness.
+
+  Writes the 16-bit MMIO register specified by Address with the byte-reversed
+  version of the value specified by Value and returns the original Value.
+  This function must guarantee that all MMIO read and write
+  operations are serialized.
+
+  @param  Address The MMIO register to write.
+  @param  Value   The value to write to the MMIO register.
+
+  @return Value.
+
+**/
+UINT16
+EFIAPI
+BeMmioWrite16 (
+  IN      UINTN                     Address,
+  IN      UINT16                    Value
+  );
+
+/**
+  Reads a 16-bit MMIO register of opposite endianness, performs a bitwise OR,
+  and writes the result back to the 16-bit MMIO register.
+
+  Reads the 16-bit MMIO register specified by Address, byte-reverses the read
+  result, performs a bitwise OR between the read result and the value specified
+  by OrData, byte-reverses the result, and writes the result to the 16-bit MMIO
+  register specified by Address. The pre-reversal value written to the MMIO
+  register is returned.
+  This function must guarantee that all MMIO read and write
+  operations are serialized.
+
+  @param  Address The MMIO register to write.
+  @param  OrData  The value to OR with the read value from the MMIO register.
+
+  @return The value written back to the MMIO register.
+
+**/
+UINT16
+EFIAPI
+BeMmioOr16 (
+  IN      UINTN                     Address,
+  IN      UINT16                    OrData
+  );
+
+/**
+  Reads a 16-bit MMIO register of opposite endianness, performs a bitwise AND,
+  and writes the result back to the 16-bit MMIO register.
+
+  Reads the 16-bit MMIO register specified by Address, byte-reverses the read
+  result, performs a bitwise AND between the read result and the value specified
+  by AndData, byte-reverses the result, and writes the result to the 16-bit MMIO
+  register specified by Address. The pre-reversal value written to the MMIO
+  register is returned.
+  This function must guarantee that all MMIO read and write
+  operations are serialized.
+
+  @param  Address The MMIO register to write.
+  @param  AndData The value to AND with the read value from the MMIO register.
+
+  @return The value written back to the MMIO register.
+
+**/
+UINT16
+EFIAPI
+BeMmioAnd16 (
+  IN      UINTN                     Address,
+  IN      UINT16                    AndData
+  );
+
+/**
+  Reads a 16-bit MMIO register of opposite endianness, performs a bitwise AND
+  followed by a bitwise OR, and writes the result back to the 16-bit MMIO
+  register.
+
+  Reads the 16-bit MMIO register specified by Address, byte reverses the read
+  result, performs a bitwise AND between the read result and the value specified
+  by AndData, performs a bitwise OR between the result of the AND operation and
+  the value specified by OrData, byte-reverses the result, and writes the result
+  to the 16-bit MMIO register specified by Address. The pre-reversal value
+  written to the MMIO register is returned.
+  This function must guarantee that all MMIO read and write
+  operations are serialized.
+
+  @param  Address The MMIO register to write.
+  @param  AndData The value to AND with the read value from the MMIO register.
+  @param  OrData  The value to OR with the result of the AND operation.
+
+  @return The value written back to the MMIO register.
+
+**/
+UINT16
+EFIAPI
+BeMmioAndThenOr16 (
+  IN      UINTN                     Address,
+  IN      UINT16                    AndData,
+  IN      UINT16                    OrData
+  );
+
+/**
+  Reads a 32-bit MMIO register of opposite endianness.
+
+  Reads the 32-bit MMIO register specified by Address.
+  The 32-bit read value is returned in reversed byte order.
+  This function must guarantee that all MMIO read and write
+  operations are serialized.
+
+  @param  Address The MMIO register to read.
+
+  @return The value read.
+
+**/
+UINT32
+EFIAPI
+BeMmioRead32 (
+  IN      UINTN                     Address
+  );
+
+/**
+  Writes a 32-bit MMIO register of opposite endianness.
+
+  Writes the 32-bit MMIO register specified by Address with the byte-reversed
+  version of the value specified by Value and returns the original Value.
+  This function must guarantee that all MMIO read and write
+  operations are serialized.
+
+  @param  Address The MMIO register to write.
+  @param  Value   The value to write to the MMIO register.
+
+  @return Value.
+
+**/
+UINT32
+EFIAPI
+BeMmioWrite32 (
+  IN      UINTN                     Address,
+  IN      UINT32                    Value
+  );
+
+/**
+  Reads a 32-bit MMIO register of opposite endianness, performs a bitwise OR,
+  and writes the result back to the 32-bit MMIO register.
+
+  Reads the 32-bit MMIO register specified by Address, byte-reverses the read
+  result, performs a bitwise OR between the read result and the value specified
+  by OrData, byte-reverses the result, and writes the result to the 32-bit MMIO
+  register specified by Address. The pre-reversal value written to the MMIO
+  register is returned.
+  This function must guarantee that all MMIO read and write
+  operations are serialized.
+
+  @param  Address The MMIO register to write.
+  @param  OrData  The value to OR with the read value from the MMIO register.
+
+  @return The value written back to the MMIO register.
+
+**/
+UINT32
+EFIAPI
+BeMmioOr32 (
+  IN      UINTN                     Address,
+  IN      UINT32                    OrData
+  );
+
+/**
+  Reads a 32-bit MMIO register of opposite endianness, performs a bitwise AND,
+  and writes the result back to the 32-bit MMIO register.
+
+  Reads the 32-bit MMIO register specified by Address, byte-reverses the read
+  result, performs a bitwise AND between the read result and the value specified
+  by AndData, byte-reverses the result, and writes the result to the 32-bit MMIO
+  register specified by Address. The pre-reversal value written to the MMIO
+  register is returned.
+  This function must guarantee that all MMIO read and write
+  operations are serialized.
+
+  @param  Address The MMIO register to write.
+  @param  AndData The value to AND with the read value from the MMIO register.
+
+  @return The value written back to the MMIO register.
+
+**/
+UINT32
+EFIAPI
+BeMmioAnd32 (
+  IN      UINTN                     Address,
+  IN      UINT32                    AndData
+  );
+
+/**
+  Reads a 32-bit MMIO register of opposite endianness, performs a bitwise AND
+  followed by a bitwise OR, and writes the result back to the 32-bit MMIO
+  register.
+
+  Reads the 32-bit MMIO register specified by Address, byte reverses the read
+  value, performs a bitwise AND between the read result and the value specified
+  by AndData, performs a bitwise OR between the result of the AND operation and
+  the value specified by OrData, byte-reverses the result, and writes the result
+  to the 32-bit MMIO register specified by Address. The pre-reversal value
+  written to the MMIO register is returned.
+  This function must guarantee that all MMIO read and write
+  operations are serialized.
+
+  @param  Address The MMIO register to write.
+  @param  AndData The value to AND with the read value from the MMIO register.
+  @param  OrData  The value to OR with the result of the AND operation.
+
+  @return The value written back to the MMIO register.
+
+**/
+UINT32
+EFIAPI
+BeMmioAndThenOr32 (
+  IN      UINTN                     Address,
+  IN      UINT32                    AndData,
+  IN      UINT32                    OrData
+  );
+
+/**
+  Reads a 64-bit MMIO register of opposite endianness.
+
+  Reads the 64-bit MMIO register specified by Address.
+  The 64-bit read value is returned in reversed byte order.
+  This function must guarantee that all MMIO read and write
+  operations are serialized.
+
+  @param  Address The MMIO register to read.
+
+  @return The value read.
+
+**/
+UINT64
+EFIAPI
+BeMmioRead64 (
+  IN      UINTN                     Address
+  );
+
+/**
+  Writes a 64-bit MMIO register of opposite endianness.
+
+  Writes the 64-bit MMIO register specified by Address with the byte-reversed
+  version of the value specified by Value and returns Value.
+  This function must guarantee that all MMIO read and write
+  operations are serialized.
+
+  @param  Address The MMIO register to write.
+  @param  Value   The value to write to the MMIO register.
+
+**/
+UINT64
+EFIAPI
+BeMmioWrite64 (
+  IN      UINTN                     Address,
+  IN      UINT64                    Value
+  );
+
+/**
+  Reads a 64-bit MMIO register of opposite endianness, performs a bitwise OR,
+  and writes the result back to the 64-bit MMIO register.
+
+  Reads the 64-bit MMIO register specified by Address, byte reverses the read
+  result, performs a bitwise OR between the read result and the value specified
+  by OrData, byte-reverses the result, and writes the result to the 64-bit MMIO
+  register specified by Address. The pre-reversal value written to the
+  MMIO register is returned.
+  This function must guarantee that all MMIO read and write
+  operations are serialized.
+
+  @param  Address The MMIO register to write.
+  @param  OrData  The value to OR with the read value from the MMIO register.
+
+  @return The value written back to the MMIO register.
+
+**/
+UINT64
+EFIAPI
+BeMmioOr64 (
+  IN      UINTN                     Address,
+  IN      UINT64                    OrData
+  );
+
+/**
+  Reads a 64-bit MMIO register of opposite endianness, performs a bitwise AND,
+  and writes the result back to the 64-bit MMIO register.
+
+  Reads the 64-bit MMIO register specified by Address, byte-reverses the read
+  value, performs a bitwise AND between the read result and the value specified
+  by AndData, byte-reverses the result, and writes the result to the 64-bit MMIO
+  register specified by Address. The pre-reversal value written to the MMIO
+  register is returned.
+  This function must guarantee that all MMIO read and write
+  operations are serialized.
+
+  @param  Address The MMIO register to write.
+  @param  AndData The value to AND with the read value from the MMIO register.
+
+  @return The value written back to the MMIO register.
+
+**/
+UINT64
+EFIAPI
+BeMmioAnd64 (
+  IN      UINTN                     Address,
+  IN      UINT64                    AndData
+  );
+
+/**
+  Reads a 64-bit MMIO register of opposite endianness, performs a bitwise AND
+  followed by a bitwise OR, and writes the result back to the 64-bit MMIO
+  register.
+
+  Reads the 64-bit MMIO register specified by Address, byte-reverses the read
+  result, performs a bitwise AND between the read result and the value specified
+  by AndData, performs a bitwise OR between the result of the AND operation and
+  the value specified by OrData, byte-reverses the result, and writes the result
+  to the 64-bit MMIO register specified by Address. The pre-reversal value
+  written to the MMIO register is returned.
+  This function must guarantee that all MMIO read and write
+  operations are serialized.
+
+  @param  Address The MMIO register to write.
+  @param  AndData The value to AND with the read value from the MMIO register.
+  @param  OrData  The value to OR with the result of the AND operation.
+
+  @return The value written back to the MMIO register.
+
+**/
+UINT64
+EFIAPI
+BeMmioAndThenOr64 (
+  IN      UINTN                     Address,
+  IN      UINT64                    AndData,
+  IN      UINT64                    OrData
+  );
+
+#endif
diff --git a/MdePkg/Library/BaseIoLibSwap/BaseBeIoLib.inf b/MdePkg/Library/BaseIoLibSwap/BaseBeIoLib.inf
new file mode 100644
index 0000000000..fbd68b9929
--- /dev/null
+++ b/MdePkg/Library/BaseIoLibSwap/BaseBeIoLib.inf
@@ -0,0 +1,48 @@
+## @file
+#  Byte swapping I/O Library.
+#
+#  Byte swapping I/O Library for all architectures. Only MMIO supported. I/O
+#  accesses take place through the normal IoLib, but values read and written
+#  are byte-reversed to interact with peripherals of non-native endianness.
+#
+#  Copyright (c) 2007 - 2015, Intel Corporation. All rights reserved.<BR>
+#  Portions copyright (c) 2008 - 2009, Apple Inc. All rights reserved.<BR>
+#  Copyright (c) 2017, AMD Incorporated. All rights reserved.<BR>
+#
+#  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.
+#
+##
+
+[Defines]
+  INF_VERSION                    = 0x0001001a
+  BASE_NAME                      = BaseBeIoLib
+  MODULE_UNI_FILE                = BaseIoLibSwap.uni
+  FILE_GUID                      = 073c3fbd-ff0d-41b6-a209-1e42fd2a3bab
+  MODULE_TYPE                    = BASE
+  VERSION_STRING                 = 1.0
+  LIBRARY_CLASS                  = BeIoLib
+
+
+#
+#  VALID_ARCHITECTURES           = IA32 X64 EBC IPF ARM AARCH64
+#
+
+[Sources]
+  IoLibSwap.c
+
+[Packages]
+  MdePkg/MdePkg.dec
+
+[LibraryClasses]
+  BaseLib
+  IoLib
+
+[BuildOptions]
+  GCC:*_*_*_CC_FLAGS             = -D FUNCTION_PREFIX=Be
+  INTEL:*_*_*_CC_FLAGS           = /D FUNCTION_PREFIX=Be
+  MSFT:*_*_*_CC_FLAGS            = /D FUNCTION_PREFIX=Be
diff --git a/MdePkg/Library/BaseIoLibSwap/BaseIoLibSwap.uni b/MdePkg/Library/BaseIoLibSwap/BaseIoLibSwap.uni
new file mode 100644
index 0000000000..e35b4abef7
--- /dev/null
+++ b/MdePkg/Library/BaseIoLibSwap/BaseIoLibSwap.uni
@@ -0,0 +1,23 @@
+// /** @file
+// Byte swapping I/O Library.
+//
+// Byte swapping I/O Library for all architectures. Only MMIO supported. I/O
+// accesses take place through the normal IoLib, but values read and written
+// are byte-reversed to interact with peripherals of non-native endianness.
+//
+// Copyright (c) 2018, Linaro ltd. All rights reserved.<BR>
+//
+// 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.
+//
+// **/
+
+
+#string STR_MODULE_ABSTRACT             #language en-US "Byte swapping I/O Library"
+
+#string STR_MODULE_DESCRIPTION          #language en-US "Byte swapping I/O Library for all architectures. Only MMIO supported. I/O accesses take place through the normal IoLib, but values read and written are byte-reversed to interact with peripherals of non-native endianness."
+
diff --git a/MdePkg/Library/BaseIoLibSwap/IoLibSwap.c b/MdePkg/Library/BaseIoLibSwap/IoLibSwap.c
new file mode 100644
index 0000000000..f4f49f72d2
--- /dev/null
+++ b/MdePkg/Library/BaseIoLibSwap/IoLibSwap.c
@@ -0,0 +1,477 @@
+/** @file
+  Provide byte-swapping services to access MMIO registers.
+
+Copyright (c) 2006 - 2012, Intel Corporation. All rights reserved.<BR>
+Copyright (c) 2017, AMD Incorporated. All rights reserved.<BR>
+Copyright (c) 2018, Linaro ltd. All rights reserved.<BR>
+
+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.
+
+**/
+
+#include <Library/BaseLib.h>
+#include <Library/IoLib.h>
+
+#define __CONCATENATE(a, b) a ## b
+#define _CONCATENATE(a, b) __CONCATENATE(a, b)
+#define ADD_PREFIX(name) _CONCATENATE (FUNCTION_PREFIX, name)
+
+/**
+  Reads a 16-bit MMIO register of opposite endianness.
+
+  Reads the 16-bit MMIO register specified by Address.
+  The 16-bit read value is returned in reversed byte order.
+  This function must guarantee that all MMIO read and write
+  operations are serialized.
+
+  @param  Address The MMIO register to read.
+
+  @return The value read.
+
+**/
+UINT16
+EFIAPI
+ADD_PREFIX (MmioRead16) (
+  IN      UINTN                     Address
+  )
+{
+  return SwapBytes16 (MmioRead16 (Address));
+}
+
+/**
+  Writes a 16-bit MMIO register of opposite endianness.
+
+  Writes the 16-bit MMIO register specified by Address with the byte-reversed
+  version of the value specified by Value and returns the original Value.
+  This function must guarantee that all MMIO read and write
+  operations are serialized.
+
+  @param  Address The MMIO register to write.
+  @param  Value   The value to write to the MMIO register.
+
+  @return Value.
+
+**/
+UINT16
+EFIAPI
+ADD_PREFIX (MmioWrite16) (
+  IN      UINTN                     Address,
+  IN      UINT16                    Value
+  )
+{
+  (VOID) MmioWrite16 (Address, SwapBytes16 (Value));
+
+  return Value;
+}
+
+/**
+  Reads a 16-bit MMIO register of opposite endianness, performs a bitwise OR,
+  and writes the result back to the 16-bit MMIO register.
+
+  Reads the 16-bit MMIO register specified by Address, byte-reverses the read
+  result, performs a bitwise OR between the read result and the value specified
+  by OrData, byte-reverses the result, and writes the result to the 16-bit MMIO
+  register specified by Address. The pre-reversal value written to the MMIO
+  register is returned.
+  This function must guarantee that all MMIO read and write
+  operations are serialized.
+
+  @param  Address The MMIO register to write.
+  @param  OrData  The value to OR with the read value from the MMIO register.
+
+  @return The value written back to the MMIO register.
+
+**/
+UINT16
+EFIAPI
+ADD_PREFIX (MmioOr16) (
+  IN      UINTN                     Address,
+  IN      UINT16                    OrData
+  )
+{
+  UINT16 Value;
+
+  Value = ADD_PREFIX (MmioRead16) (Address);
+  Value |= OrData;
+
+  return ADD_PREFIX (MmioWrite16) (Address, Value);
+}
+
+/**
+  Reads a 16-bit MMIO register of opposite endianness, performs a bitwise AND,
+  and writes the result back to the 16-bit MMIO register.
+
+  Reads the 16-bit MMIO register specified by Address, byte-reverses the read
+  result, performs a bitwise AND between the read result and the value specified
+  by AndData, byte-reverses the result, and writes the result to the 16-bit MMIO
+  register specified by Address. The pre-reversal value written to the MMIO
+  register is returned.
+  This function must guarantee that all MMIO read and write
+  operations are serialized.
+
+  @param  Address The MMIO register to write.
+  @param  AndData The value to AND with the read value from the MMIO register.
+
+  @return The value written back to the MMIO register.
+
+**/
+UINT16
+EFIAPI
+ADD_PREFIX (MmioAnd16) (
+  IN      UINTN                     Address,
+  IN      UINT16                    AndData
+  )
+{
+  UINT16 Value;
+
+  Value = ADD_PREFIX (MmioRead16) (Address);
+  Value &= AndData;
+
+  return ADD_PREFIX (MmioWrite16) (Address, Value);
+}
+
+/**
+  Reads a 16-bit MMIO register of opposite endianness, performs a bitwise AND
+  followed by a bitwise OR, and writes the result back to the 16-bit MMIO
+  register.
+
+  Reads the 16-bit MMIO register specified by Address, byte reverses the read
+  result, performs a bitwise AND between the read result and the value specified
+  by AndData, performs a bitwise OR between the result of the AND operation and
+  the value specified by OrData, byte-reverses the result, and writes the result
+  to the 16-bit MMIO register specified by Address. The pre-reversal value
+  written to the MMIO register is returned.
+  This function must guarantee that all MMIO read and write
+  operations are serialized.
+
+  @param  Address The MMIO register to write.
+  @param  AndData The value to AND with the read value from the MMIO register.
+  @param  OrData  The value to OR with the result of the AND operation.
+
+  @return The value written back to the MMIO register.
+
+**/
+UINT16
+EFIAPI
+ADD_PREFIX (MmioAndThenOr16) (
+  IN      UINTN                     Address,
+  IN      UINT16                    AndData,
+  IN      UINT16                    OrData
+  )
+{
+  UINT16 Value;
+
+  Value = ADD_PREFIX (MmioRead16) (Address);
+  Value &= AndData;
+  Value |= OrData;
+
+  return ADD_PREFIX (MmioWrite16) (Address, Value);
+}
+
+/**
+  Reads a 32-bit MMIO register of opposite endianness.
+
+  Reads the 32-bit MMIO register specified by Address.
+  The 32-bit read value is returned in reversed byte order.
+  This function must guarantee that all MMIO read and write
+  operations are serialized.
+
+  @param  Address The MMIO register to read.
+
+  @return The value read.
+
+**/
+UINT32
+EFIAPI
+ADD_PREFIX (MmioRead32) (
+  IN      UINTN                     Address
+  )
+{
+  return SwapBytes32 (MmioRead32 (Address));
+}
+
+/**
+  Writes a 32-bit MMIO register of opposite endianness.
+
+  Writes the 32-bit MMIO register specified by Address with the byte-reversed
+  version of the value specified by Value and returns the original Value.
+  This function must guarantee that all MMIO read and write
+  operations are serialized.
+
+  @param  Address The MMIO register to write.
+  @param  Value   The value to write to the MMIO register.
+
+  @return Value.
+
+**/
+UINT32
+EFIAPI
+ADD_PREFIX (MmioWrite32) (
+  IN      UINTN                     Address,
+  IN      UINT32                    Value
+  )
+{
+  (VOID) MmioWrite32 (Address, SwapBytes32 (Value));
+
+  return Value;
+}
+
+/**
+  Reads a 32-bit MMIO register of opposite endianness, performs a bitwise OR,
+  and writes the result back to the 32-bit MMIO register.
+
+  Reads the 32-bit MMIO register specified by Address, byte-reverses the read
+  result, performs a bitwise OR between the read result and the value specified
+  by OrData, byte-reverses the result, and writes the result to the 32-bit MMIO
+  register specified by Address. The pre-reversal value written to the MMIO
+  register is returned.
+  This function must guarantee that all MMIO read and write
+  operations are serialized.
+
+  @param  Address The MMIO register to write.
+  @param  OrData  The value to OR with the read value from the MMIO register.
+
+  @return The value written back to the MMIO register.
+
+**/
+UINT32
+EFIAPI
+ADD_PREFIX (MmioOr32) (
+  IN      UINTN                     Address,
+  IN      UINT32                    OrData
+  )
+{
+  UINT32 Value;
+
+  Value = ADD_PREFIX (MmioRead32) (Address);
+  Value |= OrData;
+
+  return ADD_PREFIX (MmioWrite32) (Address, Value);
+}
+
+/**
+  Reads a 32-bit MMIO register of opposite endianness, performs a bitwise AND,
+  and writes the result back to the 32-bit MMIO register.
+
+  Reads the 32-bit MMIO register specified by Address, byte-reverses the read
+  result, performs a bitwise AND between the read result and the value specified
+  by AndData, byte-reverses the result, and writes the result to the 32-bit MMIO
+  register specified by Address. The pre-reversal value written to the MMIO
+  register is returned.
+  This function must guarantee that all MMIO read and write
+  operations are serialized.
+
+  @param  Address The MMIO register to write.
+  @param  AndData The value to AND with the read value from the MMIO register.
+
+  @return The value written back to the MMIO register.
+
+**/
+UINT32
+EFIAPI
+ADD_PREFIX (MmioAnd32) (
+  IN      UINTN                     Address,
+  IN      UINT32                    AndData
+  )
+{
+  UINT32 Value;
+
+  Value = ADD_PREFIX (MmioRead32) (Address);
+  Value &= AndData;
+
+  return ADD_PREFIX (MmioWrite32) (Address, Value);
+}
+
+/**
+  Reads a 32-bit MMIO register of opposite endianness, performs a bitwise AND
+  followed by a bitwise OR, and writes the result back to the 32-bit MMIO
+  register.
+
+  Reads the 32-bit MMIO register specified by Address, byte reverses the read
+  value, performs a bitwise AND between the read result and the value specified
+  by AndData, performs a bitwise OR between the result of the AND operation and
+  the value specified by OrData, byte-reverses the result, and writes the result
+  to the 32-bit MMIO register specified by Address. The pre-reversal value
+  written to the MMIO register is returned.
+  This function must guarantee that all MMIO read and write
+  operations are serialized.
+
+  @param  Address The MMIO register to write.
+  @param  AndData The value to AND with the read value from the MMIO register.
+  @param  OrData  The value to OR with the result of the AND operation.
+
+  @return The value written back to the MMIO register.
+
+**/
+UINT32
+EFIAPI
+ADD_PREFIX (MmioAndThenOr32) (
+  IN      UINTN                     Address,
+  IN      UINT32                    AndData,
+  IN      UINT32                    OrData
+  )
+{
+  UINT32 Value;
+
+  Value = ADD_PREFIX (MmioRead32) (Address);
+  Value &= AndData;
+  Value |= OrData;
+
+  return ADD_PREFIX (MmioWrite32) (Address, Value);
+}
+
+/**
+  Reads a 64-bit MMIO register of opposite endianness.
+
+  Reads the 64-bit MMIO register specified by Address.
+  The 64-bit read value is returned in reversed byte order.
+  This function must guarantee that all MMIO read and write
+  operations are serialized.
+
+  @param  Address The MMIO register to read.
+
+  @return The value read.
+
+**/
+UINT64
+EFIAPI
+ADD_PREFIX (MmioRead64) (
+  IN      UINTN                     Address
+  )
+{
+  return SwapBytes64 (MmioRead64 (Address));
+}
+
+/**
+  Writes a 64-bit MMIO register of opposite endianness.
+
+  Writes the 64-bit MMIO register specified by Address with the byte-reversed
+  version of the value specified by Value and returns Value.
+  This function must guarantee that all MMIO read and write
+  operations are serialized.
+
+  @param  Address The MMIO register to write.
+  @param  Value   The value to write to the MMIO register.
+
+**/
+UINT64
+EFIAPI
+ADD_PREFIX (MmioWrite64) (
+  IN      UINTN                     Address,
+  IN      UINT64                    Value
+  )
+{
+  (VOID) MmioWrite64 (Address, SwapBytes64 (Value));
+
+  return Value;
+}
+
+/**
+  Reads a 64-bit MMIO register of opposite endianness, performs a bitwise OR,
+  and writes the result back to the 64-bit MMIO register.
+
+  Reads the 64-bit MMIO register specified by Address, byte reverses the read
+  result, performs a bitwise OR between the read result and the value specified
+  by OrData, byte-reverses the result, and writes the result to the 64-bit MMIO
+  register specified by Address. The pre-reversal value written to the
+  MMIO register is returned.
+  This function must guarantee that all MMIO read and write
+  operations are serialized.
+
+  @param  Address The MMIO register to write.
+  @param  OrData  The value to OR with the read value from the MMIO register.
+
+  @return The value written back to the MMIO register.
+
+**/
+UINT64
+EFIAPI
+ADD_PREFIX (MmioOr64) (
+  IN      UINTN                     Address,
+  IN      UINT64                    OrData
+  )
+{
+  UINT64 Value;
+
+  Value = ADD_PREFIX (MmioRead64) (Address);
+  Value |= OrData;
+
+  return ADD_PREFIX (MmioWrite64) (Address, Value);
+}
+
+/**
+  Reads a 64-bit MMIO register of opposite endianness, performs a bitwise AND,
+  and writes the result back to the 64-bit MMIO register.
+
+  Reads the 64-bit MMIO register specified by Address, byte-reverses the read
+  value, performs a bitwise AND between the read result and the value specified
+  by AndData, byte-reverses the result, and writes the result to the 64-bit MMIO
+  register specified by Address. The pre-reversal value written to the MMIO
+  register is returned.
+  This function must guarantee that all MMIO read and write
+  operations are serialized.
+
+  @param  Address The MMIO register to write.
+  @param  AndData The value to AND with the read value from the MMIO register.
+
+  @return The value written back to the MMIO register.
+
+**/
+UINT64
+EFIAPI
+ADD_PREFIX (MmioAnd64) (
+  IN      UINTN                     Address,
+  IN      UINT64                    AndData
+  )
+{
+  UINT64 Value;
+
+  Value = ADD_PREFIX (MmioRead64) (Address);
+  Value &= AndData;
+
+  return ADD_PREFIX (MmioWrite64) (Address, Value);
+}
+
+/**
+  Reads a 64-bit MMIO register of opposite endianness, performs a bitwise AND
+  followed by a bitwise OR, and writes the result back to the 64-bit MMIO
+  register.
+
+  Reads the 64-bit MMIO register specified by Address, byte-reverses the read
+  result, performs a bitwise AND between the read result and the value specified
+  by AndData, performs a bitwise OR between the result of the AND operation and
+  the value specified by OrData, byte-reverses the result, and writes the result
+  to the 64-bit MMIO register specified by Address. The pre-reversal value
+  written to the MMIO register is returned.
+  This function must guarantee that all MMIO read and write
+  operations are serialized.
+
+  @param  Address The MMIO register to write.
+  @param  AndData The value to AND with the read value from the MMIO register.
+  @param  OrData  The value to OR with the result of the AND operation.
+
+  @return The value written back to the MMIO register.
+
+**/
+UINT64
+EFIAPI
+ADD_PREFIX (MmioAndThenOr64) (
+  IN      UINTN                     Address,
+  IN      UINT64                    AndData,
+  IN      UINT64                    OrData
+  )
+{
+  UINT64 Value;
+
+  Value = ADD_PREFIX (MmioRead64) (Address);
+  Value &= AndData;
+  Value |= OrData;
+
+  return ADD_PREFIX (MmioWrite64) (Address, Value);
+}
diff --git a/MdePkg/MdePkg.dec b/MdePkg/MdePkg.dec
index 0e64f22f4a..ae7c8dfa11 100644
--- a/MdePkg/MdePkg.dec
+++ b/MdePkg/MdePkg.dec
@@ -160,6 +160,9 @@ [LibraryClasses]
   ##  @libraryclass  Provide services to access I/O Ports and MMIO registers.
   IoLib|Include/Library/IoLib.h
 
+  ##  @libraryclass  Provide big-endian services to access MMIO registers.
+  BeIoLib|Include/Library/BeIoLib.h
+
   ##  @libraryclass  Provide services to create, get and update HSTI table in AIP protocol.
   HstiLib|Include/Library/HstiLib.h
 
