ArmVirtPkg: add XenPlatformHasAcpiDtDxe

This driver produces the EDKII Platform Has ACPI and Platform Has Device
Tree protocols, exactly matching the current ACPI / DT exposure on Xen,
according to ARM vs. AARCH64. At this point it differs from the QEMU
driver PlatformHasAcpiDtDxe in that this one always installs the DT.

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

ArmVirtPkg/XenPlatformHasAcpiDtDxe/XenPlatformHasAcpiDtDxe.c

@@ -0,0 +1,72 @@
+/** @file
+  Decide whether the firmware should expose an ACPI- and/or a Device Tree-based
+  hardware description to the operating system.
+
+  Copyright (c) 2017, Red Hat, Inc.
+
+  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 <Guid/PlatformHasAcpi.h>
+#include <Guid/PlatformHasDeviceTree.h>
+#include <Library/BaseLib.h>
+#include <Library/DebugLib.h>
+#include <Library/UefiBootServicesTableLib.h>
+
+EFI_STATUS
+EFIAPI
+XenPlatformHasAcpiDt (
+  IN EFI_HANDLE       ImageHandle,
+  IN EFI_SYSTEM_TABLE *SystemTable
+  )
+{
+  EFI_STATUS Status;
+
+  //
+  // If we fail to install any of the necessary protocols below, the OS will be
+  // unbootable anyway (due to lacking hardware description), so tolerate no
+  // errors here.
+  //
+  // Always make ACPI available on 64-bit systems.
+  //
+  if (MAX_UINTN == MAX_UINT64) {
+    Status = gBS->InstallProtocolInterface (
+                    &ImageHandle,
+                    &gEdkiiPlatformHasAcpiGuid,
+                    EFI_NATIVE_INTERFACE,
+                    NULL
+                    );
+    if (EFI_ERROR (Status)) {
+      goto Failed;
+    }
+  }
+
+  //
+  // Expose the Device Tree unconditionally.
+  //
+  Status = gBS->InstallProtocolInterface (
+                  &ImageHandle,
+                  &gEdkiiPlatformHasDeviceTreeGuid,
+                  EFI_NATIVE_INTERFACE,
+                  NULL
+                  );
+  if (EFI_ERROR (Status)) {
+    goto Failed;
+  }
+
+  return Status;
+
+Failed:
+  ASSERT_EFI_ERROR (Status);
+  CpuDeadLoop ();
+  //
+  // Keep compilers happy.
+  //
+  return Status;
+}

ArmVirtPkg/XenPlatformHasAcpiDtDxe/XenPlatformHasAcpiDtDxe.inf

@@ -0,0 +1,42 @@
+## @file
+# Decide whether the firmware should expose an ACPI- and/or a Device Tree-based
+# hardware description to the operating system.
+#
+# Copyright (c) 2017, Red Hat, Inc.
+#
+# 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                    = 1.25
+  BASE_NAME                      = XenPlatformHasAcpiDtDxe
+  FILE_GUID                      = 6914c46f-d46e-48dc-9998-8a5f64f02553
+  MODULE_TYPE                    = DXE_DRIVER
+  VERSION_STRING                 = 1.0
+  ENTRY_POINT                    = XenPlatformHasAcpiDt
+
+[Sources]
+  XenPlatformHasAcpiDtDxe.c
+
+[Packages]
+  EmbeddedPkg/EmbeddedPkg.dec
+  MdePkg/MdePkg.dec
+
+[LibraryClasses]
+  BaseLib
+  DebugLib
+  UefiBootServicesTableLib
+  UefiDriverEntryPoint
+
+[Guids]
+  gEdkiiPlatformHasAcpiGuid       ## SOMETIMES_PRODUCES ## PROTOCOL
+  gEdkiiPlatformHasDeviceTreeGuid ## PRODUCES           ## PROTOCOL
+
+[Depex]
+  TRUE