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   SPDX-License-Identifier: BSD-2-Clause-Patent
   8 **/
   9
  10 #include <Guid/PlatformHasAcpi.h>
  11 #include <Guid/PlatformHasDeviceTree.h>
  12 #include <Library/BaseLib.h>
  13 #include <Library/DebugLib.h>
  14 #include <Library/PcdLib.h>
  15 #include <Library/QemuFwCfgLib.h>
  16 #include <Library/UefiBootServicesTableLib.h>
  17
  18 EFI_STATUS
  19 EFIAPI
  20 PlatformHasAcpiDt (
  21   IN EFI_HANDLE       ImageHandle,
  22   IN EFI_SYSTEM_TABLE *SystemTable
  23   )
  24 {
  25   EFI_STATUS           Status;
  26   FIRMWARE_CONFIG_ITEM FwCfgItem;
  27   UINTN                FwCfgSize;
  28
  29   //
  30   // If we fail to install any of the necessary protocols below, the OS will be
  31   // unbootable anyway (due to lacking hardware description), so tolerate no
  32   // errors here.
  33   //
  34   if (MAX_UINTN == MAX_UINT64 &&
  35       !PcdGetBool (PcdForceNoAcpi) &&
  36       !EFI_ERROR (
  37          QemuFwCfgFindFile (
  38            "etc/table-loader",
  39            &FwCfgItem,
  40            &FwCfgSize
  41            )
  42          )) {
  43     //
  44     // Only make ACPI available on 64-bit systems, and only if QEMU generates
  45     // (a subset of) the ACPI tables.
  46     //
  47     Status = gBS->InstallProtocolInterface (
  48                     &ImageHandle,
  49                     &gEdkiiPlatformHasAcpiGuid,
  50                     EFI_NATIVE_INTERFACE,
  51                     NULL
  52                     );
  53     if (EFI_ERROR (Status)) {
  54       goto Failed;
  55     }
  56
  57     return Status;
  58   }
  59
  60   //
  61   // Expose the Device Tree otherwise.
  62   //
  63   Status = gBS->InstallProtocolInterface (
  64                   &ImageHandle,
  65                   &gEdkiiPlatformHasDeviceTreeGuid,
  66                   EFI_NATIVE_INTERFACE,
  67                   NULL
  68                   );
  69   if (EFI_ERROR (Status)) {
  70     goto Failed;
  71   }
  72
  73   return Status;
  74
  75 Failed:
  76   ASSERT_EFI_ERROR (Status);
  77   CpuDeadLoop ();
  78   //
  79   // Keep compilers happy.
  80   //
  81   return Status;
  82 }