ArmVirtPkg/PlatformHasAcpiDtDxe/PlatformHasAcpiDtDxe.c

   1 /** @file
   2   Decide whether the firmware should expose an ACPI- and/or a Device Tree-based
   3   hardware description to the operating system.
   4
   5   Copyright (c) 2017, Red Hat, Inc.
   6
   7   This program and the accompanying materials are licensed and made available
   8   under the terms and conditions of the BSD License which accompanies this
   9   distribution.  The full text of the license may be found at
  10   http://opensource.org/licenses/bsd-license.php
  11
  12   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, WITHOUT
  13   WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  14 **/
  15
  16 #include <Guid/PlatformHasAcpi.h>
  17 #include <Guid/PlatformHasDeviceTree.h>
  18 #include <Library/BaseLib.h>
  19 #include <Library/DebugLib.h>
  20 #include <Library/QemuFwCfgLib.h>
  21 #include <Library/UefiBootServicesTableLib.h>
  22
  23 EFI_STATUS
  24 EFIAPI
  25 PlatformHasAcpiDt (
  26   IN EFI_HANDLE       ImageHandle,
  27   IN EFI_SYSTEM_TABLE *SystemTable
  28   )
  29 {
  30   EFI_STATUS           Status;
  31   FIRMWARE_CONFIG_ITEM FwCfgItem;
  32   UINTN                FwCfgSize;
  33
  34   //
  35   // If we fail to install any of the necessary protocols below, the OS will be
  36   // unbootable anyway (due to lacking hardware description), so tolerate no
  37   // errors here.
  38   //
  39   if (MAX_UINTN == MAX_UINT64 &&
  40       !EFI_ERROR (
  41          QemuFwCfgFindFile (
  42            "etc/table-loader",
  43            &FwCfgItem,
  44            &FwCfgSize
  45            )
  46          )) {
  47     //
  48     // Only make ACPI available on 64-bit systems, and only if QEMU generates
  49     // (a subset of) the ACPI tables.
  50     //
  51     Status = gBS->InstallProtocolInterface (
  52                     &ImageHandle,
  53                     &gEdkiiPlatformHasAcpiGuid,
  54                     EFI_NATIVE_INTERFACE,
  55                     NULL
  56                     );
  57     if (EFI_ERROR (Status)) {
  58       goto Failed;
  59     }
  60
  61     return Status;
  62   }
  63
  64   //
  65   // Expose the Device Tree otherwise.
  66   //
  67   Status = gBS->InstallProtocolInterface (
  68                   &ImageHandle,
  69                   &gEdkiiPlatformHasDeviceTreeGuid,
  70                   EFI_NATIVE_INTERFACE,
  71                   NULL
  72                   );
  73   if (EFI_ERROR (Status)) {
  74     goto Failed;
  75   }
  76
  77   return Status;
  78
  79 Failed:
  80   ASSERT_EFI_ERROR (Status);
  81   CpuDeadLoop ();
  82   //
  83   // Keep compilers happy.
  84   //
  85   return Status;
  86 }