[PATCH edk2-platforms 08/12] Hisilicon: add PciCpuIo2Dxe

[Heyi Guo <heyi.guo@linaro.org>]

This is to prepare for switching to generic PciHostBridge, and
CpuIo2Dxe is needed by generic PciHostBridge driver.

The driver is copied from ArmPkg/Drivers/ArmPciCpuIo2Dxe and changed
for D0x.

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Heyi Guo <heyi.guo@linaro.org>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Leif Lindholm <leif.lindholm@linaro.org>
Cc: Michael D Kinney <michael.d.kinney@intel.com>
---
 Silicon/Hisilicon/Drivers/ArmPciCpuIo2Dxe/ArmPciCpuIo2Dxe.inf |  48 ++
 Silicon/Hisilicon/Drivers/ArmPciCpuIo2Dxe/ArmPciCpuIo2Dxe.c   | 557 ++++++++++++++++++++
 2 files changed, 605 insertions(+)

diff --git a/Silicon/Hisilicon/Drivers/ArmPciCpuIo2Dxe/ArmPciCpuIo2Dxe.inf b/Silicon/Hisilicon/Drivers/ArmPciCpuIo2Dxe/ArmPciCpuIo2Dxe.inf
new file mode 100644
index 000000000000..fbb28319ca87
--- /dev/null
+++ b/Silicon/Hisilicon/Drivers/ArmPciCpuIo2Dxe/ArmPciCpuIo2Dxe.inf
@@ -0,0 +1,48 @@
+## @file
+#  Produces the CPU I/O 2 Protocol by using the services of the I/O Library.
+#
+# Copyright (c) 2009 - 2014, Intel Corporation. All rights reserved.<BR>
+# Copyright (c) 2016 - 2018, Linaro Ltd. All rights reserved.<BR>
+# Copyright (c) 2018, Hisilicon 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.
+#
+##
+
+[Defines]
+  INF_VERSION                    = 0x0001001A
+  BASE_NAME                      = ArmPciCpuIo2Dxe
+  FILE_GUID                      = 94577c7e-0bce-11e8-b4e8-286ed489ee9b
+  MODULE_TYPE                    = DXE_DRIVER
+  VERSION_STRING                 = 1.0
+  ENTRY_POINT                    = ArmPciCpuIo2Initialize
+
+#
+# The following information is for reference only and not required by the build tools.
+#
+#  VALID_ARCHITECTURES           = ARM AARCH64
+#
+
+[Sources]
+  ArmPciCpuIo2Dxe.c
+
+[Packages]
+  MdePkg/MdePkg.dec
+
+[LibraryClasses]
+  UefiDriverEntryPoint
+  BaseLib
+  DebugLib
+  IoLib
+
+[Protocols]
+  gEfiCpuIo2ProtocolGuid                         ## PRODUCES
+
+[Depex]
+  TRUE
diff --git a/Silicon/Hisilicon/Drivers/ArmPciCpuIo2Dxe/ArmPciCpuIo2Dxe.c b/Silicon/Hisilicon/Drivers/ArmPciCpuIo2Dxe/ArmPciCpuIo2Dxe.c
new file mode 100644
index 000000000000..8426c5935c8a
--- /dev/null
+++ b/Silicon/Hisilicon/Drivers/ArmPciCpuIo2Dxe/ArmPciCpuIo2Dxe.c
@@ -0,0 +1,557 @@
+/** @file
+  Produces the CPU I/O 2 Protocol.
+
+Copyright (c) 2009 - 2012, Intel Corporation. All rights reserved.<BR>
+Copyright (c) 2016 - 2018, Linaro Ltd. All rights reserved.<BR>
+Copyright (c) 2018, Hisilicon 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 <PiDxe.h>
+
+#include <Protocol/CpuIo2.h>
+
+#include <Library/BaseLib.h>
+#include <Library/DebugLib.h>
+#include <Library/IoLib.h>
+#include <Library/PcdLib.h>
+#include <Library/UefiBootServicesTableLib.h>
+
+// The translated IO PORT address is already a MMIO address, so we make it the
+// same as memory address for range check.
+#define MAX_IO_PORT_ADDRESS   MAX_ADDRESS
+
+//
+// Lookup table for increment values based on transfer widths
+//
+STATIC CONST UINT8 mInStride[] = {
+  1, // EfiCpuIoWidthUint8
+  2, // EfiCpuIoWidthUint16
+  4, // EfiCpuIoWidthUint32
+  8, // EfiCpuIoWidthUint64
+  0, // EfiCpuIoWidthFifoUint8
+  0, // EfiCpuIoWidthFifoUint16
+  0, // EfiCpuIoWidthFifoUint32
+  0, // EfiCpuIoWidthFifoUint64
+  1, // EfiCpuIoWidthFillUint8
+  2, // EfiCpuIoWidthFillUint16
+  4, // EfiCpuIoWidthFillUint32
+  8  // EfiCpuIoWidthFillUint64
+};
+
+//
+// Lookup table for increment values based on transfer widths
+//
+STATIC CONST UINT8 mOutStride[] = {
+  1, // EfiCpuIoWidthUint8
+  2, // EfiCpuIoWidthUint16
+  4, // EfiCpuIoWidthUint32
+  8, // EfiCpuIoWidthUint64
+  1, // EfiCpuIoWidthFifoUint8
+  2, // EfiCpuIoWidthFifoUint16
+  4, // EfiCpuIoWidthFifoUint32
+  8, // EfiCpuIoWidthFifoUint64
+  0, // EfiCpuIoWidthFillUint8
+  0, // EfiCpuIoWidthFillUint16
+  0, // EfiCpuIoWidthFillUint32
+  0  // EfiCpuIoWidthFillUint64
+};
+
+/**
+  Check parameters to a CPU I/O 2 Protocol service request.
+
+  The I/O operations are carried out exactly as requested. The caller is responsible
+  for satisfying any alignment and I/O width restrictions that a PI System on a
+  platform might require. For example on some platforms, width requests of
+  EfiCpuIoWidthUint64 do not work. Misaligned buffers, on the other hand, will
+  be handled by the driver.
+
+  @param[in] MmioOperation  TRUE for an MMIO operation, FALSE for I/O Port operation.
+  @param[in] Width          Signifies the width of the I/O or Memory operation.
+  @param[in] Address        The base address of the I/O operation.
+  @param[in] Count          The number of I/O operations to perform. The number of
+                            bytes moved is Width size * Count, starting at Address.
+  @param[in] Buffer         For read operations, the destination buffer to store the results.
+                            For write operations, the source buffer from which to write data.
+
+  @retval EFI_SUCCESS            The parameters for this request pass the checks.
+  @retval EFI_INVALID_PARAMETER  Width is invalid for this PI system.
+  @retval EFI_INVALID_PARAMETER  Buffer is NULL.
+  @retval EFI_UNSUPPORTED        The Buffer is not aligned for the given Width.
+  @retval EFI_UNSUPPORTED        The address range specified by Address, Width,
+                                 and Count is not valid for this PI system.
+
+**/
+STATIC
+EFI_STATUS
+CpuIoCheckParameter (
+  IN BOOLEAN                    MmioOperation,
+  IN EFI_CPU_IO_PROTOCOL_WIDTH  Width,
+  IN UINT64                     Address,
+  IN UINTN                      Count,
+  IN VOID                       *Buffer
+  )
+{
+  UINT64  MaxCount;
+  UINT64  Limit;
+
+  //
+  // Check to see if Buffer is NULL
+  //
+  if (Buffer == NULL) {
+    return EFI_INVALID_PARAMETER;
+  }
+
+  //
+  // Check to see if Width is in the valid range
+  //
+  if ((UINT32)Width >= EfiCpuIoWidthMaximum) {
+    return EFI_INVALID_PARAMETER;
+  }
+
+  //
+  // For FIFO type, the target address won't increase during the access,
+  // so treat Count as 1
+  //
+  if (Width >= EfiCpuIoWidthFifoUint8 && Width <= EfiCpuIoWidthFifoUint64) {
+    Count = 1;
+  }
+
+  //
+  // Check to see if Width is in the valid range for I/O Port operations
+  //
+  Width = (EFI_CPU_IO_PROTOCOL_WIDTH) (Width & 0x03);
+  if (!MmioOperation && (Width == EfiCpuIoWidthUint64)) {
+    return EFI_INVALID_PARAMETER;
+  }
+
+  //
+  // Check to see if Address is aligned
+  //
+  if ((Address & (UINT64)(mInStride[Width] - 1)) != 0) {
+    return EFI_UNSUPPORTED;
+  }
+
+  //
+  // Check to see if any address associated with this transfer exceeds the maximum
+  // allowed address.  The maximum address implied by the parameters passed in is
+  // Address + Size * Count.  If the following condition is met, then the transfer
+  // is not supported.
+  //
+  //    Address + Size * Count > (MmioOperation ? MAX_ADDRESS : MAX_IO_PORT_ADDRESS) + 1
+  //
+  // Since MAX_ADDRESS can be the maximum integer value supported by the CPU and Count
+  // can also be the maximum integer value supported by the CPU, this range
+  // check must be adjusted to avoid all oveflow conditions.
+  //
+  // The following form of the range check is equivalent but assumes that
+  // MAX_ADDRESS and MAX_IO_PORT_ADDRESS are of the form (2^n - 1).
+  //
+  Limit = (MmioOperation ? MAX_ADDRESS : MAX_IO_PORT_ADDRESS);
+  if (Count == 0) {
+    if (Address > Limit) {
+      return EFI_UNSUPPORTED;
+    }
+  } else {
+    MaxCount = RShiftU64 (Limit, Width);
+    if (MaxCount < (Count - 1)) {
+      return EFI_UNSUPPORTED;
+    }
+    if (Address > LShiftU64 (MaxCount - Count + 1, Width)) {
+      return EFI_UNSUPPORTED;
+    }
+  }
+
+  //
+  // Check to see if Buffer is aligned
+  //
+  if (((UINTN)Buffer & ((MIN (sizeof (UINTN), mInStride[Width])  - 1))) != 0) {
+    return EFI_UNSUPPORTED;
+  }
+
+  return EFI_SUCCESS;
+}
+
+/**
+  Reads memory-mapped registers.
+
+  The I/O operations are carried out exactly as requested. The caller is responsible
+  for satisfying any alignment and I/O width restrictions that a PI System on a
+  platform might require. For example on some platforms, width requests of
+  EfiCpuIoWidthUint64 do not work. Misaligned buffers, on the other hand, will
+  be handled by the driver.
+
+  If Width is EfiCpuIoWidthUint8, EfiCpuIoWidthUint16, EfiCpuIoWidthUint32,
+  or EfiCpuIoWidthUint64, then both Address and Buffer are incremented for
+  each of the Count operations that is performed.
+
+  If Width is EfiCpuIoWidthFifoUint8, EfiCpuIoWidthFifoUint16,
+  EfiCpuIoWidthFifoUint32, or EfiCpuIoWidthFifoUint64, then only Buffer is
+  incremented for each of the Count operations that is performed. The read or
+  write operation is performed Count times on the same Address.
+
+  If Width is EfiCpuIoWidthFillUint8, EfiCpuIoWidthFillUint16,
+  EfiCpuIoWidthFillUint32, or EfiCpuIoWidthFillUint64, then only Address is
+  incremented for each of the Count operations that is performed. The read or
+  write operation is performed Count times from the first element of Buffer.
+
+  @param[in]  This     A pointer to the EFI_CPU_IO2_PROTOCOL instance.
+  @param[in]  Width    Signifies the width of the I/O or Memory operation.
+  @param[in]  Address  The base address of the I/O operation.
+  @param[in]  Count    The number of I/O operations to perform. The number of
+                       bytes moved is Width size * Count, starting at Address.
+  @param[out] Buffer   For read operations, the destination buffer to store the results.
+                       For write operations, the source buffer from which to write data.
+
+  @retval EFI_SUCCESS            The data was read from or written to the PI system.
+  @retval EFI_INVALID_PARAMETER  Width is invalid for this PI system.
+  @retval EFI_INVALID_PARAMETER  Buffer is NULL.
+  @retval EFI_UNSUPPORTED        The Buffer is not aligned for the given Width.
+  @retval EFI_UNSUPPORTED        The address range specified by Address, Width,
+                                 and Count is not valid for this PI system.
+
+**/
+STATIC
+EFI_STATUS
+EFIAPI
+CpuMemoryServiceRead (
+  IN  EFI_CPU_IO2_PROTOCOL       *This,
+  IN  EFI_CPU_IO_PROTOCOL_WIDTH  Width,
+  IN  UINT64                     Address,
+  IN  UINTN                      Count,
+  OUT VOID                       *Buffer
+  )
+{
+  EFI_STATUS                 Status;
+  UINT8                      InStride;
+  UINT8                      OutStride;
+  EFI_CPU_IO_PROTOCOL_WIDTH  OperationWidth;
+  UINT8                      *Uint8Buffer;
+
+  Status = CpuIoCheckParameter (TRUE, Width, Address, Count, Buffer);
+  if (EFI_ERROR (Status)) {
+    return Status;
+  }
+
+  //
+  // Select loop based on the width of the transfer
+  //
+  InStride = mInStride[Width];
+  OutStride = mOutStride[Width];
+  OperationWidth = (EFI_CPU_IO_PROTOCOL_WIDTH) (Width & 0x03);
+  for (Uint8Buffer = Buffer; Count > 0; Address += InStride, Uint8Buffer += OutStride, Count--) {
+    if (OperationWidth == EfiCpuIoWidthUint8) {
+      *Uint8Buffer = MmioRead8 ((UINTN)Address);
+    } else if (OperationWidth == EfiCpuIoWidthUint16) {
+      *((UINT16 *)Uint8Buffer) = MmioRead16 ((UINTN)Address);
+    } else if (OperationWidth == EfiCpuIoWidthUint32) {
+      *((UINT32 *)Uint8Buffer) = MmioRead32 ((UINTN)Address);
+    } else if (OperationWidth == EfiCpuIoWidthUint64) {
+      *((UINT64 *)Uint8Buffer) = MmioRead64 ((UINTN)Address);
+    }
+  }
+  return EFI_SUCCESS;
+}
+
+/**
+  Writes memory-mapped registers.
+
+  The I/O operations are carried out exactly as requested. The caller is responsible
+  for satisfying any alignment and I/O width restrictions that a PI System on a
+  platform might require. For example on some platforms, width requests of
+  EfiCpuIoWidthUint64 do not work. Misaligned buffers, on the other hand, will
+  be handled by the driver.
+
+  If Width is EfiCpuIoWidthUint8, EfiCpuIoWidthUint16, EfiCpuIoWidthUint32,
+  or EfiCpuIoWidthUint64, then both Address and Buffer are incremented for
+  each of the Count operations that is performed.
+
+  If Width is EfiCpuIoWidthFifoUint8, EfiCpuIoWidthFifoUint16,
+  EfiCpuIoWidthFifoUint32, or EfiCpuIoWidthFifoUint64, then only Buffer is
+  incremented for each of the Count operations that is performed. The read or
+  write operation is performed Count times on the same Address.
+
+  If Width is EfiCpuIoWidthFillUint8, EfiCpuIoWidthFillUint16,
+  EfiCpuIoWidthFillUint32, or EfiCpuIoWidthFillUint64, then only Address is
+  incremented for each of the Count operations that is performed. The read or
+  write operation is performed Count times from the first element of Buffer.
+
+  @param[in]  This     A pointer to the EFI_CPU_IO2_PROTOCOL instance.
+  @param[in]  Width    Signifies the width of the I/O or Memory operation.
+  @param[in]  Address  The base address of the I/O operation.
+  @param[in]  Count    The number of I/O operations to perform. The number of
+                       bytes moved is Width size * Count, starting at Address.
+  @param[in]  Buffer   For read operations, the destination buffer to store the results.
+                       For write operations, the source buffer from which to write data.
+
+  @retval EFI_SUCCESS            The data was read from or written to the PI system.
+  @retval EFI_INVALID_PARAMETER  Width is invalid for this PI system.
+  @retval EFI_INVALID_PARAMETER  Buffer is NULL.
+  @retval EFI_UNSUPPORTED        The Buffer is not aligned for the given Width.
+  @retval EFI_UNSUPPORTED        The address range specified by Address, Width,
+                                 and Count is not valid for this PI system.
+
+**/
+STATIC
+EFI_STATUS
+EFIAPI
+CpuMemoryServiceWrite (
+  IN EFI_CPU_IO2_PROTOCOL       *This,
+  IN EFI_CPU_IO_PROTOCOL_WIDTH  Width,
+  IN UINT64                     Address,
+  IN UINTN                      Count,
+  IN VOID                       *Buffer
+  )
+{
+  EFI_STATUS                 Status;
+  UINT8                      InStride;
+  UINT8                      OutStride;
+  EFI_CPU_IO_PROTOCOL_WIDTH  OperationWidth;
+  UINT8                      *Uint8Buffer;
+
+  Status = CpuIoCheckParameter (TRUE, Width, Address, Count, Buffer);
+  if (EFI_ERROR (Status)) {
+    return Status;
+  }
+
+  //
+  // Select loop based on the width of the transfer
+  //
+  InStride = mInStride[Width];
+  OutStride = mOutStride[Width];
+  OperationWidth = (EFI_CPU_IO_PROTOCOL_WIDTH) (Width & 0x03);
+  for (Uint8Buffer = Buffer; Count > 0; Address += InStride, Uint8Buffer += OutStride, Count--) {
+    if (OperationWidth == EfiCpuIoWidthUint8) {
+      MmioWrite8 ((UINTN)Address, *Uint8Buffer);
+    } else if (OperationWidth == EfiCpuIoWidthUint16) {
+      MmioWrite16 ((UINTN)Address, *((UINT16 *)Uint8Buffer));
+    } else if (OperationWidth == EfiCpuIoWidthUint32) {
+      MmioWrite32 ((UINTN)Address, *((UINT32 *)Uint8Buffer));
+    } else if (OperationWidth == EfiCpuIoWidthUint64) {
+      MmioWrite64 ((UINTN)Address, *((UINT64 *)Uint8Buffer));
+    }
+  }
+  return EFI_SUCCESS;
+}
+
+/**
+  Reads I/O registers.
+
+  The I/O operations are carried out exactly as requested. The caller is responsible
+  for satisfying any alignment and I/O width restrictions that a PI System on a
+  platform might require. For example on some platforms, width requests of
+  EfiCpuIoWidthUint64 do not work. Misaligned buffers, on the other hand, will
+  be handled by the driver.
+
+  If Width is EfiCpuIoWidthUint8, EfiCpuIoWidthUint16, EfiCpuIoWidthUint32,
+  or EfiCpuIoWidthUint64, then both Address and Buffer are incremented for
+  each of the Count operations that is performed.
+
+  If Width is EfiCpuIoWidthFifoUint8, EfiCpuIoWidthFifoUint16,
+  EfiCpuIoWidthFifoUint32, or EfiCpuIoWidthFifoUint64, then only Buffer is
+  incremented for each of the Count operations that is performed. The read or
+  write operation is performed Count times on the same Address.
+
+  If Width is EfiCpuIoWidthFillUint8, EfiCpuIoWidthFillUint16,
+  EfiCpuIoWidthFillUint32, or EfiCpuIoWidthFillUint64, then only Address is
+  incremented for each of the Count operations that is performed. The read or
+  write operation is performed Count times from the first element of Buffer.
+
+  @param[in]  This     A pointer to the EFI_CPU_IO2_PROTOCOL instance.
+  @param[in]  Width    Signifies the width of the I/O or Memory operation.
+  @param[in]  Address  The base address of the I/O operation.
+  @param[in]  Count    The number of I/O operations to perform. The number of
+                       bytes moved is Width size * Count, starting at Address.
+  @param[out] Buffer   For read operations, the destination buffer to store the results.
+                       For write operations, the source buffer from which to write data.
+
+  @retval EFI_SUCCESS            The data was read from or written to the PI system.
+  @retval EFI_INVALID_PARAMETER  Width is invalid for this PI system.
+  @retval EFI_INVALID_PARAMETER  Buffer is NULL.
+  @retval EFI_UNSUPPORTED        The Buffer is not aligned for the given Width.
+  @retval EFI_UNSUPPORTED        The address range specified by Address, Width,
+                                 and Count is not valid for this PI system.
+
+**/
+STATIC
+EFI_STATUS
+EFIAPI
+CpuIoServiceRead (
+  IN  EFI_CPU_IO2_PROTOCOL       *This,
+  IN  EFI_CPU_IO_PROTOCOL_WIDTH  Width,
+  IN  UINT64                     Address,
+  IN  UINTN                      Count,
+  OUT VOID                       *Buffer
+  )
+{
+  EFI_STATUS                 Status;
+  UINT8                      InStride;
+  UINT8                      OutStride;
+  EFI_CPU_IO_PROTOCOL_WIDTH  OperationWidth;
+  UINT8                      *Uint8Buffer;
+
+  Status = CpuIoCheckParameter (FALSE, Width, Address, Count, Buffer);
+  if (EFI_ERROR (Status)) {
+    return Status;
+  }
+
+  //
+  // Select loop based on the width of the transfer
+  //
+  InStride = mInStride[Width];
+  OutStride = mOutStride[Width];
+  OperationWidth = (EFI_CPU_IO_PROTOCOL_WIDTH) (Width & 0x03);
+
+  // Assuming address has already been translated into MMIO address by PCI host
+  // bridge driver, so we call MmioRead/Write directly.
+  for (Uint8Buffer = Buffer; Count > 0; Address += InStride, Uint8Buffer += OutStride, Count--) {
+    if (OperationWidth == EfiCpuIoWidthUint8) {
+      *Uint8Buffer = MmioRead8 ((UINTN)Address);
+    } else if (OperationWidth == EfiCpuIoWidthUint16) {
+      *((UINT16 *)Uint8Buffer) = MmioRead16 ((UINTN)Address);
+    } else if (OperationWidth == EfiCpuIoWidthUint32) {
+      *((UINT32 *)Uint8Buffer) = MmioRead32 ((UINTN)Address);
+    }
+  }
+
+  return EFI_SUCCESS;
+}
+
+/**
+  Write I/O registers.
+
+  The I/O operations are carried out exactly as requested. The caller is responsible
+  for satisfying any alignment and I/O width restrictions that a PI System on a
+  platform might require. For example on some platforms, width requests of
+  EfiCpuIoWidthUint64 do not work. Misaligned buffers, on the other hand, will
+  be handled by the driver.
+
+  If Width is EfiCpuIoWidthUint8, EfiCpuIoWidthUint16, EfiCpuIoWidthUint32,
+  or EfiCpuIoWidthUint64, then both Address and Buffer are incremented for
+  each of the Count operations that is performed.
+
+  If Width is EfiCpuIoWidthFifoUint8, EfiCpuIoWidthFifoUint16,
+  EfiCpuIoWidthFifoUint32, or EfiCpuIoWidthFifoUint64, then only Buffer is
+  incremented for each of the Count operations that is performed. The read or
+  write operation is performed Count times on the same Address.
+
+  If Width is EfiCpuIoWidthFillUint8, EfiCpuIoWidthFillUint16,
+  EfiCpuIoWidthFillUint32, or EfiCpuIoWidthFillUint64, then only Address is
+  incremented for each of the Count operations that is performed. The read or
+  write operation is performed Count times from the first element of Buffer.
+
+  @param[in]  This     A pointer to the EFI_CPU_IO2_PROTOCOL instance.
+  @param[in]  Width    Signifies the width of the I/O or Memory operation.
+  @param[in]  Address  The base address of the I/O operation.
+  @param[in]  Count    The number of I/O operations to perform. The number of
+                       bytes moved is Width size * Count, starting at Address.
+  @param[in]  Buffer   For read operations, the destination buffer to store the results.
+                       For write operations, the source buffer from which to write data.
+
+  @retval EFI_SUCCESS            The data was read from or written to the PI system.
+  @retval EFI_INVALID_PARAMETER  Width is invalid for this PI system.
+  @retval EFI_INVALID_PARAMETER  Buffer is NULL.
+  @retval EFI_UNSUPPORTED        The Buffer is not aligned for the given Width.
+  @retval EFI_UNSUPPORTED        The address range specified by Address, Width,
+                                 and Count is not valid for this PI system.
+
+**/
+STATIC
+EFI_STATUS
+EFIAPI
+CpuIoServiceWrite (
+  IN EFI_CPU_IO2_PROTOCOL       *This,
+  IN EFI_CPU_IO_PROTOCOL_WIDTH  Width,
+  IN UINT64                     Address,
+  IN UINTN                      Count,
+  IN VOID                       *Buffer
+  )
+{
+  EFI_STATUS                 Status;
+  UINT8                      InStride;
+  UINT8                      OutStride;
+  EFI_CPU_IO_PROTOCOL_WIDTH  OperationWidth;
+  UINT8                      *Uint8Buffer;
+
+  //
+  // Make sure the parameters are valid
+  //
+  Status = CpuIoCheckParameter (FALSE, Width, Address, Count, Buffer);
+  if (EFI_ERROR (Status)) {
+    return Status;
+  }
+
+  //
+  // Select loop based on the width of the transfer
+  //
+  InStride = mInStride[Width];
+  OutStride = mOutStride[Width];
+  OperationWidth = (EFI_CPU_IO_PROTOCOL_WIDTH) (Width & 0x03);
+
+  // Assuming address has already been translated into MMIO address by PCI host
+  // bridge driver, so we call MmioRead/Write directly.
+  for (Uint8Buffer = (UINT8 *)Buffer; Count > 0; Address += InStride, Uint8Buffer += OutStride, Count--) {
+    if (OperationWidth == EfiCpuIoWidthUint8) {
+      MmioWrite8 ((UINTN)Address, *Uint8Buffer);
+    } else if (OperationWidth == EfiCpuIoWidthUint16) {
+      MmioWrite16 ((UINTN)Address, *((UINT16 *)Uint8Buffer));
+    } else if (OperationWidth == EfiCpuIoWidthUint32) {
+      MmioWrite32 ((UINTN)Address, *((UINT32 *)Uint8Buffer));
+    }
+  }
+
+  return EFI_SUCCESS;
+}
+
+//
+// CPU I/O 2 Protocol instance
+//
+STATIC EFI_CPU_IO2_PROTOCOL mCpuIo2 = {
+  {
+    CpuMemoryServiceRead,
+    CpuMemoryServiceWrite
+  },
+  {
+    CpuIoServiceRead,
+    CpuIoServiceWrite
+  }
+};
+
+
+/**
+  The user Entry Point for module CpuIo2Dxe. 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
+ArmPciCpuIo2Initialize (
+  IN EFI_HANDLE        ImageHandle,
+  IN EFI_SYSTEM_TABLE  *SystemTable
+  )
+{
+  EFI_STATUS Status;
+
+  ASSERT_PROTOCOL_ALREADY_INSTALLED (NULL, &gEfiCpuIo2ProtocolGuid);
+  Status = gBS->InstallMultipleProtocolInterfaces (
+                  &ImageHandle,
+                  &gEfiCpuIo2ProtocolGuid, &mCpuIo2,
+                  NULL
+                  );
+  ASSERT_EFI_ERROR (Status);
+
+  return Status;
+}
-- 
2.7.4