MdeModulePkg/Library/DxeDpcLib/DpcLib.c

   1 /** @file
   2   Help functions to access UDP service.
   3
   4 Copyright (c) 2005 - 2018, Intel Corporation. All rights reserved.<BR>
   5 SPDX-License-Identifier: BSD-2-Clause-Patent
   6 **/
   7
   8 #include <Uefi.h>
   9 #include <Library/DebugLib.h>
  10 #include <Library/UefiBootServicesTableLib.h>
  11 #include <Protocol/Dpc.h>
  12
  13 //
  14 // Pointer to the DPC Protocol
  15 //
  16 EFI_DPC_PROTOCOL  *mDpc;
  17
  18 /**
  19   This constructor function caches the EFI_DPC_PROTOCOL pointer.
  20
  21   @param[in] ImageHandle The firmware allocated handle for the EFI image.
  22   @param[in] SystemTable A pointer to the EFI System Table.
  23
  24   @retval EFI_SUCCESS The constructor always return EFI_SUCCESS.
  25
  26 **/
  27 EFI_STATUS
  28 EFIAPI
  29 DpcLibConstructor (
  30   IN EFI_HANDLE        ImageHandle,
  31   IN EFI_SYSTEM_TABLE  *SystemTable
  32   )
  33 {
  34   EFI_STATUS  Status;
  35
  36   //
  37   // Locate the EFI_DPC_PROTOCOL in the handle database
  38   //
  39   Status = gBS->LocateProtocol (&gEfiDpcProtocolGuid, NULL, (VOID **)&mDpc);
  40   ASSERT_EFI_ERROR (Status);
  41
  42   return Status;
  43 }
  44
  45 /**
  46   Add a Deferred Procedure Call to the end of the DPC queue.
  47
  48   @param[in]  DpcTpl        The EFI_TPL that the DPC should be invoked.
  49   @param[in]  DpcProcedure  Pointer to the DPC's function.
  50   @param[in]  DpcContext    Pointer to the DPC's context.  Passed to DpcProcedure
  51                             when DpcProcedure is invoked.
  52
  53   @retval EFI_SUCCESS            The DPC was queued.
  54   @retval EFI_INVALID_PARAMETER  DpcTpl is not a valid EFI_TPL.
  55   @retval EFI_INVALID_PARAMETER  DpcProcedure is NULL.
  56   @retval EFI_OUT_OF_RESOURCES   There are not enough resources available to
  57                                  add the DPC to the queue.
  58
  59 **/
  60 EFI_STATUS
  61 EFIAPI
  62 QueueDpc (
  63   IN EFI_TPL            DpcTpl,
  64   IN EFI_DPC_PROCEDURE  DpcProcedure,
  65   IN VOID               *DpcContext    OPTIONAL
  66   )
  67 {
  68   //
  69   // Call the EFI_DPC_PROTOCOL to queue the DPC
  70   //
  71   return mDpc->QueueDpc (mDpc, DpcTpl, DpcProcedure, DpcContext);
  72 }
  73
  74 /**
  75   Dispatch the queue of DPCs.  ALL DPCs that have been queued with a DpcTpl
  76   value greater than or equal to the current TPL are invoked in the order that
  77   they were queued.  DPCs with higher DpcTpl values are invoked before DPCs with
  78   lower DpcTpl values.
  79
  80   @retval EFI_SUCCESS    One or more DPCs were invoked.
  81   @retval EFI_NOT_FOUND  No DPCs were invoked.
  82
  83 **/
  84 EFI_STATUS
  85 EFIAPI
  86 DispatchDpc (
  87   VOID
  88   )
  89 {
  90   //
  91   // Call the EFI_DPC_PROTOCOL to dispatch previously queued DPCs
  92   //
  93   return mDpc->DispatchDpc (mDpc);
  94 }