ArmPkg: implement CpuIo2 protocol driver specific for PCI

The CpuIo2 protocol is required by the generic PciHostBridgeDxe driver,
which relies on it to back its own I/O and MMIO operations.

Since ARM has no native I/O port equivalent, such accesses can only
originate from PCI drivers, and the PCI I/O space is translated to MMIO
in this case.

So we can implement this protocol using MMIO operations only, and take
the PCI I/O translation offset into account when performing I/O port
accesses.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Leif Lindholm <leif.lindholm@linaro.org>

ArmPkg/Drivers/ArmPciCpuIo2Dxe/ArmPciCpuIo2Dxe.inf

@@ -0,0 +1,53 @@
+## @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, 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.
+#
+##
+
+[Defines]
+  INF_VERSION                    = 0x00010005
+  BASE_NAME                      = ArmPciCpuIo2Dxe
+  FILE_GUID                      = 168D1A6E-F4A5-448A-9E95-795661BB3067
+  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]
+  ArmPkg/ArmPkg.dec
+  MdePkg/MdePkg.dec
+
+[LibraryClasses]
+  UefiDriverEntryPoint
+  BaseLib
+  DebugLib
+  IoLib
+  PcdLib
+  UefiBootServicesTableLib
+
+[Pcd]
+  gArmTokenSpaceGuid.PcdPciIoTranslation
+
+[Protocols]
+  gEfiCpuIo2ProtocolGuid                         ## PRODUCES
+
+[Depex]
+  TRUE