Add ArmPlatformPkg from ARM Ltd. patch.

git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@11291 6f19259b-4bc3-4df7-8a09-765794883524

ArmPlatformPkg/ArmRealViewEbPkg/Library/DebugAgentTimerLib/DebugAgentTimerLib.c

@@ -0,0 +1,80 @@
+/** @file
+  Template for ArmEb DebugAgentLib. 
+
+  For ARM we reserve FIQ for the Debug Agent Timer. We don't care about 
+  laytency as we only really need the timer to run a few times a second 
+  (how fast can some one type a ctrl-c?), but it works much better if
+  the interrupt we are using to break into the debugger is not being
+  used, and masked, by the system. 
+
+  Copyright (c) 2008 - 2010, Apple Inc. All rights reserved.<BR>
+  
+  This program and the accompanying materials
+  are licensed and made available under the terms and conditions of the BSD License
+  which accompanies this distribution.  The full text of the license may be found at
+  http://opensource.org/licenses/bsd-license.php
+
+  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
+  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+
+**/
+
+#include <Base.h>
+
+#include <Library/DebugAgentTimerLib.h>
+
+#include <ArmEb/ArmEb.h>
+
+
+/**
+  Setup all the hardware needed for the debug agents timer.
+
+  This function is used to set up debug enviroment. 
+
+**/
+VOID
+EFIAPI
+DebugAgentTimerIntialize (
+  VOID
+  )
+{
+  // Map Timer to FIQ
+}
+  
+  
+/**
+  Set the period for the debug agent timer. Zero means disable the timer.
+
+  @param[in] TimerPeriodMilliseconds    Frequency of the debug agent timer.
+
+**/  
+VOID
+EFIAPI
+DebugAgentTimerSetPeriod (
+  IN  UINT32  TimerPeriodMilliseconds
+  )
+{
+  if (TimerPeriodMilliseconds == 0) {
+    // Disable timer and Disable FIQ
+    return;
+  } 
+
+  // Set timer period and unmask FIQ
+}
+  
+
+/**
+  Perform End Of Interrupt for the debug agent timer. This is called in the 
+  interrupt handler after the interrupt has been processed. 
+
+**/  
+VOID
+EFIAPI
+DebugAgentTimerEndOfInterrupt (
+  VOID
+  )
+{
+  // EOI Timer interrupt for FIQ
+}
+  
+