git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@10418 6f19259b-4bc3-4df7-8a09-765794883524
		
			
				
	
	
		
			348 lines
		
	
	
		
			9.2 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			348 lines
		
	
	
		
			9.2 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
| /** @file
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| 
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| Copyright (c) 2007 - 2008, Intel Corporation. All rights reserved.<BR>
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| This program and the accompanying materials
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| are licensed and made available under the terms and conditions of the BSD License
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| which accompanies this distribution.  The full text of the license may be found at
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| http://opensource.org/licenses/bsd-license.php
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| 
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| THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
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| WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
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| 
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| Module Name:
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| 
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|   Dpc.c
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| 
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| Abstract:
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| 
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| 
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| **/
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| 
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| #include "Dpc.h"
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| 
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| //
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| // Handle for the EFI_DPC_PROTOCOL instance
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| //
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| EFI_HANDLE  mDpcHandle = NULL;
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| 
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| //
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| // The EFI_DPC_PROTOCOL instances that is installed onto mDpcHandle
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| //
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| EFI_DPC_PROTOCOL mDpc = {
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|   DpcQueueDpc,
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|   DpcDispatchDpc
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| };
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| 
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| //
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| // Global variables used to meaasure the DPC Queue Depths
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| //
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| UINTN  mDpcQueueDepth = 0;
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| UINTN  mMaxDpcQueueDepth = 0;
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| 
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| //
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| // Free list of DPC entries.  As DPCs are queued, entries are removed from this
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| // free list.  As DPC entries are dispatched, DPC entries are added to the free list.
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| // If the free list is empty and a DPC is queued, the free list is grown by allocating
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| // an additional set of DPC entries.
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| //
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| LIST_ENTRY      mDpcEntryFreeList = INITIALIZE_LIST_HEAD_VARIABLE(mDpcEntryFreeList);
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| 
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| //
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| // An array of DPC queues.  A DPC queue is allocated for every leval EFI_TPL value.
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| // As DPCs are queued, they are added to the end of the linked list.
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| // As DPCs are dispatched, they are removed from the beginning of the linked list.
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| //
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| LIST_ENTRY      mDpcQueue[TPL_HIGH_LEVEL + 1];
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| 
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| /**
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|   Add a Deferred Procedure Call to the end of the DPC queue.
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| 
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|   @param  This          Protocol instance pointer.
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|   @param  DpcTpl        The EFI_TPL that the DPC should be invoked.
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|   @param  DpcProcedure  Pointer to the DPC's function.
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|   @param  DpcContext    Pointer to the DPC's context.  Passed to DpcProcedure
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|                         when DpcProcedure is invoked.
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| 
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|   @retval EFI_SUCCESS            The DPC was queued.
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|   @retval EFI_INVALID_PARAMETER  DpcTpl is not a valid EFI_TPL.
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|   @retval EFI_INVALID_PARAMETER  DpcProcedure is NULL.
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|   @retval EFI_OUT_OF_RESOURCES   There are not enough resources available to
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|                                  add the DPC to the queue.
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| 
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| **/
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| EFI_STATUS
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| EFIAPI
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| DpcQueueDpc (
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|   IN EFI_DPC_PROTOCOL   *This,
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|   IN EFI_TPL            DpcTpl,
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|   IN EFI_DPC_PROCEDURE  DpcProcedure,
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|   IN VOID               *DpcContext    OPTIONAL
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|   )
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| {
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|   EFI_STATUS  ReturnStatus;
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|   EFI_TPL     OriginalTpl;
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|   DPC_ENTRY   *DpcEntry;
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|   UINTN       Index;
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| 
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|   //
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|   // Make sure DpcTpl is valid
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|   //
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|   if (DpcTpl < TPL_APPLICATION || DpcTpl > TPL_HIGH_LEVEL) {
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|     return EFI_INVALID_PARAMETER;
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|   }
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| 
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|   //
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|   // Make sure DpcProcedure is valid
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|   //
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|   if (DpcProcedure == NULL) {
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|     return EFI_INVALID_PARAMETER;
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|   }
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| 
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|   //
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|   // Assume this function will succeed
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|   //
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|   ReturnStatus = EFI_SUCCESS;
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| 
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|   //
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|   // Raise the TPL level to TPL_HIGH_LEVEL for DPC list operation and save the
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|   // current TPL value so it can be restored when this function returns.
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|   //
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|   OriginalTpl = gBS->RaiseTPL (TPL_HIGH_LEVEL);
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| 
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|   //
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|   // Check to see if there are any entries in the DPC free list
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|   //
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|   if (IsListEmpty (&mDpcEntryFreeList)) {
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|     //
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|     // If the current TPL is greater than TPL_NOTIFY, then memory allocations
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|     // can not be performed, so the free list can not be expanded.  In this case
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|     // return EFI_OUT_OF_RESOURCES.
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|     //
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|     if (OriginalTpl > TPL_NOTIFY) {
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|       ReturnStatus = EFI_OUT_OF_RESOURCES;
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|       goto Done;
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|     }
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| 
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|     //
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|     // Add 64 DPC entries to the free list
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|     //
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|     for (Index = 0; Index < 64; Index++) {
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|       //
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|       // Lower the TPL level to perform a memory allocation
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|       //
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|       gBS->RestoreTPL (OriginalTpl);
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| 
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|       //
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|       // Allocate a new DPC entry
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|       //
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|       DpcEntry = AllocatePool (sizeof (DPC_ENTRY));
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| 
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|       //
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|       // Raise the TPL level back to TPL_HIGH_LEVEL for DPC list operations
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|       //
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|       gBS->RaiseTPL (TPL_HIGH_LEVEL);
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| 
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|       //
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|       // If the allocation of a DPC entry fails, and the free list is empty,
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|       // then return EFI_OUT_OF_RESOURCES.
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|       //
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|       if (DpcEntry == NULL) {
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|         if (IsListEmpty (&mDpcEntryFreeList)) {
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|           ReturnStatus = EFI_OUT_OF_RESOURCES;
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|           goto Done;
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|         }
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|       }
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| 
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|       //
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|       // Add the newly allocated DPC entry to the DPC free list
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|       //
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|       InsertTailList (&mDpcEntryFreeList, &DpcEntry->ListEntry);
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|     }
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|   }
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| 
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|   //
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|   // Retrieve the first node from the free list of DPCs
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|   //
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|   DpcEntry = (DPC_ENTRY *)(GetFirstNode (&mDpcEntryFreeList));
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| 
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|   //
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|   // Remove the first node from the free list of DPCs
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|   //
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|   RemoveEntryList (&DpcEntry->ListEntry);
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| 
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|   //
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|   // Fill in the DPC entry with the DpcProcedure and DpcContext
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|   //
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|   DpcEntry->DpcProcedure = DpcProcedure;
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|   DpcEntry->DpcContext   = DpcContext;
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| 
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|   //
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|   // Add the DPC entry to the end of the list for the specified DplTpl.
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|   //
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|   InsertTailList (&mDpcQueue[DpcTpl], &DpcEntry->ListEntry);
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| 
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|   //
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|   // Increment the measured DPC queue depth across all TPLs
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|   //
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|   mDpcQueueDepth++;
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| 
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|   //
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|   // Measure the maximum DPC queue depth across all TPLs
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|   //
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|   if (mDpcQueueDepth > mMaxDpcQueueDepth) {
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|     mMaxDpcQueueDepth = mDpcQueueDepth;
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|   }
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| 
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| Done:
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|   //
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|   // Restore the original TPL level when this function was called
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|   //
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|   gBS->RestoreTPL (OriginalTpl);
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| 
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|   return ReturnStatus;
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| }
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| 
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| /**
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|   Dispatch the queue of DPCs.  ALL DPCs that have been queued with a DpcTpl
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|   value greater than or equal to the current TPL are invoked in the order that
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|   they were queued.  DPCs with higher DpcTpl values are invoked before DPCs with
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|   lower DpcTpl values.
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| 
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|   @param  This  Protocol instance pointer.
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| 
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|   @retval EFI_SUCCESS    One or more DPCs were invoked.
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|   @retval EFI_NOT_FOUND  No DPCs were invoked.
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| 
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| **/
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| EFI_STATUS
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| EFIAPI
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| DpcDispatchDpc (
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|   IN EFI_DPC_PROTOCOL  *This
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|   )
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| {
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|   EFI_STATUS  ReturnStatus;
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|   EFI_TPL     OriginalTpl;
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|   EFI_TPL     Tpl;
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|   DPC_ENTRY   *DpcEntry;
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| 
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|   //
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|   // Assume that no DPCs will be invoked
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|   //
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|   ReturnStatus = EFI_NOT_FOUND;
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| 
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|   //
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|   // Raise the TPL level to TPL_HIGH_LEVEL for DPC list operation and save the
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|   // current TPL value so it can be restored when this function returns.
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|   //
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|   OriginalTpl = gBS->RaiseTPL (TPL_HIGH_LEVEL);
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| 
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|   //
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|   // Check to see if there are 1 or more DPCs currently queued
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|   //
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|   if (mDpcQueueDepth > 0) {
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|     //
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|     // Loop from TPL_HIGH_LEVEL down to the current TPL value
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|     //
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|     for (Tpl = TPL_HIGH_LEVEL; Tpl >= OriginalTpl; Tpl--) {
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|       //
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|       // Check to see if the DPC queue is empty
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|       //
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|       while (!IsListEmpty (&mDpcQueue[Tpl])) {
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|         //
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|         // Retrieve the first DPC entry from the DPC queue specified by Tpl
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|         //
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|         DpcEntry = (DPC_ENTRY *)(GetFirstNode (&mDpcQueue[Tpl]));
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| 
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|         //
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|         // Remove the first DPC entry from the DPC queue specified by Tpl
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|         //
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|         RemoveEntryList (&DpcEntry->ListEntry);
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| 
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|         //
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|         // Decrement the measured DPC Queue Depth across all TPLs
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|         //
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|         mDpcQueueDepth--;
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| 
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|         //
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|         // Lower the TPL to TPL value of the current DPC queue
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|         //
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|         gBS->RestoreTPL (Tpl);
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| 
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|         //
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|         // Invoke the DPC passing in its context
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|         //
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|         (DpcEntry->DpcProcedure) (DpcEntry->DpcContext);
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| 
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|         //
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|         // At least one DPC has been invoked, so set the return status to EFI_SUCCESS
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|         //
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|         ReturnStatus = EFI_SUCCESS;
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| 
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|         //
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|         // Raise the TPL level back to TPL_HIGH_LEVEL for DPC list operations
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|         //
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|         gBS->RaiseTPL (TPL_HIGH_LEVEL);
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| 
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|         //
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|         // Add the invoked DPC entry to the DPC free list
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|         //
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|         InsertTailList (&mDpcEntryFreeList, &DpcEntry->ListEntry);
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|       }
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|     }
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|   }
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| 
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|   //
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|   // Restore the original TPL level when this function was called
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|   //
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|   gBS->RestoreTPL (OriginalTpl);
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| 
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|   return ReturnStatus;
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| }
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| 
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| /**
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|   The entry point for DPC driver which installs the EFI_DPC_PROTOCOL onto a new handle.
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| 
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|   @param  ImageHandle            The image handle of the driver.
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|   @param  SystemTable            The system table.
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| 
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|   @retval EFI_SUCCES             The DPC queues were initialized and the EFI_DPC_PROTOCOL was
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|                                  installed onto a new handle.
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|   @retval Others                 Failed to install EFI_DPC_PROTOCOL.
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| 
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| **/
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| EFI_STATUS
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| EFIAPI
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| DpcDriverEntryPoint (
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|   IN EFI_HANDLE        ImageHandle,
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|   IN EFI_SYSTEM_TABLE  *SystemTable
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|   )
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| {
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|   EFI_STATUS  Status;
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|   UINTN       Index;
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| 
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|   //
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|   // ASSERT() if the EFI_DPC_PROTOCOL is already present in the handle database
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|   //
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|   ASSERT_PROTOCOL_ALREADY_INSTALLED (NULL, &gEfiDpcProtocolGuid);
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| 
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|   //
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|   // Initialize the DPC queue for all possible TPL values
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|   //
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|   for (Index = 0; Index <= TPL_HIGH_LEVEL; Index++) {
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|     InitializeListHead (&mDpcQueue[Index]);
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|   }
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| 
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|   //
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|   // Install the EFI_DPC_PROTOCOL instance onto a new handle
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|   //
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|   Status = gBS->InstallMultipleProtocolInterfaces (
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|                   &mDpcHandle,
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|                   &gEfiDpcProtocolGuid, 
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|                   &mDpc,
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|                   NULL
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|                   );
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|   ASSERT_EFI_ERROR (Status);
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| 
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|   return Status;
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| }
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