audk/OvmfPkg/AcpiPlatformDxe/EntryPoint.c

/** @file
  Entry point of OVMF ACPI Platform Driver

  Copyright (C) 2015, Red Hat, Inc.
  Copyright (c) 2008 - 2015, Intel Corporation. All rights reserved.<BR>

  SPDX-License-Identifier: BSD-2-Clause-Patent
**/

#include <Guid/RootBridgesConnectedEventGroup.h> // gRootBridgesConnectedEve...
#include <Library/DebugLib.h>                    // DEBUG()
#include <Library/PcdLib.h>                      // PcdGetBool()
#include <Library/UefiBootServicesTableLib.h>    // gBS
#include <Protocol/AcpiTable.h>                  // EFI_ACPI_TABLE_PROTOCOL

#include "AcpiPlatform.h"

STATIC
EFI_ACPI_TABLE_PROTOCOL *
FindAcpiTableProtocol (
  VOID
  )
{
  EFI_STATUS               Status;
  EFI_ACPI_TABLE_PROTOCOL  *AcpiTable;

  Status = gBS->LocateProtocol (
                  &gEfiAcpiTableProtocolGuid,
                  NULL,
                  (VOID **)&AcpiTable
                  );
  ASSERT_EFI_ERROR (Status);
  return AcpiTable;
}

STATIC
VOID
EFIAPI
OnRootBridgesConnected (
  IN EFI_EVENT  Event,
  IN VOID       *Context
  )
{
  EFI_STATUS  Status;

  DEBUG ((
    DEBUG_INFO,
    "%a: root bridges have been connected, installing ACPI tables\n",
    __func__
    ));
  Status = InstallAcpiTables (FindAcpiTableProtocol ());
  if (EFI_ERROR (Status)) {
    DEBUG ((DEBUG_ERROR, "%a: InstallAcpiTables: %r\n", __func__, Status));
  }

  gBS->CloseEvent (Event);
}

EFI_STATUS
EFIAPI
AcpiPlatformEntryPoint (
  IN EFI_HANDLE        ImageHandle,
  IN EFI_SYSTEM_TABLE  *SystemTable
  )
{
  EFI_STATUS  Status;
  EFI_EVENT   RootBridgesConnected;

  //
  // If the platform doesn't support PCI, or PCI enumeration has been disabled,
  // install the tables at once, and let the entry point's return code reflect
  // the full functionality.
  //
  if (PcdGetBool (PcdPciDisableBusEnumeration)) {
    DEBUG ((
      DEBUG_INFO,
      "%a: PCI or its enumeration disabled, installing "
      "ACPI tables\n",
      __func__
      ));
    return InstallAcpiTables (FindAcpiTableProtocol ());
  }

  //
  // Otherwise, delay installing the ACPI tables until root bridges are
  // connected. The entry point's return status will only reflect the callback
  // setup. (Note that we're a DXE_DRIVER; our entry point function is invoked
  // strictly before BDS is entered and can connect the root bridges.)
  //
  Status = gBS->CreateEventEx (
                  EVT_NOTIFY_SIGNAL,
                  TPL_CALLBACK,
                  OnRootBridgesConnected,
                  NULL /* Context */,
                  &gRootBridgesConnectedEventGroupGuid,
                  &RootBridgesConnected
                  );
  if (!EFI_ERROR (Status)) {
    DEBUG ((
      DEBUG_INFO,
      "%a: waiting for root bridges to be connected, registered callback\n",
      __func__
      ));
  }

  return Status;
}