PlatformHasAcpiDtDxe.c

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#include <Guid/PlatformHasAcpi.h>
#include <Guid/PlatformHasDeviceTree.h>
#include <Library/BaseLib.h>
#include <Library/DebugLib.h>
#include <Library/PcdLib.h>
#include <Library/QemuFwCfgLib.h>
#include <Library/UefiBootServicesTableLib.h>
 
EFI_STATUS
EFIAPI
PlatformHasAcpiDt (
  IN EFI_HANDLE        ImageHandle,
  IN EFI_SYSTEM_TABLE  *SystemTable
  )
{
  EFI_STATUS            Status;
  FIRMWARE_CONFIG_ITEM  FwCfgItem;
  UINTN                 FwCfgSize;
 
  //
  // 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.
  //
  if ((MAX_UINTN == MAX_UINT64) &&
      !PcdGetBool (PcdForceNoAcpi) &&
      !EFI_ERROR (
         QemuFwCfgFindFile (
           "etc/table-loader",
           &FwCfgItem,
           &FwCfgSize
           )
         ))
  {
    //
    // Only make ACPI available on 64-bit systems, and only if QEMU generates
    // (a subset of) the ACPI tables.
    //
    Status = gBS->InstallProtocolInterface (
                    &ImageHandle,
                    &gEdkiiPlatformHasAcpiGuid,
                    EFI_NATIVE_INTERFACE,
                    NULL
                    );
    if (EFI_ERROR (Status)) {
      goto Failed;
    }
 
    return Status;
  }
 
  //
  // Expose the Device Tree otherwise.
  //
  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;
}