SourceLevelDebugPkg/Library/DebugAgent/DebugAgentCommon/DebugTimer.c

   1 /** @file
   2   Code for debug timer to support debug agent library implementation.
   3
   4   Copyright (c) 2010 - 2015, Intel Corporation. All rights reserved.<BR>
   5   This program and the accompanying materials
   6   are licensed and made available under the terms and conditions of the BSD License
   7   which accompanies this distribution.  The full text of the license may be found at
   8   http://opensource.org/licenses/bsd-license.php.
   9
  10   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  11   WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  12
  13 **/
  14
  15 #include "DebugAgent.h"
  16
  17 /**
  18   Initialize CPU local APIC timer.
  19
  20   @param[out] TimerFrequency  Local APIC timer frequency returned.
  21
  22   @return   32-bit Local APIC timer init count.
  23 **/
  24 UINT32
  25 InitializeDebugTimer (
  26   OUT UINT32     *TimerFrequency
  27   )
  28 {
  29   UINTN       ApicTimerDivisor;
  30   UINT32      InitialCount;
  31   UINT32      ApicTimerFrequency;
  32
  33   GetApicTimerState (&ApicTimerDivisor, NULL, NULL);
  34   ApicTimerFrequency = PcdGet32(PcdFSBClock) / (UINT32)ApicTimerDivisor;
  35   //
  36   // Cpu Local Apic timer interrupt frequency, it is set to 0.1s
  37   //
  38   InitialCount = (UINT32)DivU64x32 (
  39                    MultU64x64 (
  40                      ApicTimerFrequency,
  41                      DEBUG_TIMER_INTERVAL
  42                      ),
  43                    1000000u
  44                    );
  45
  46   InitializeApicTimer (ApicTimerDivisor, InitialCount, TRUE, DEBUG_TIMER_VECTOR);
  47
  48   DEBUG ((EFI_D_INFO, "Debug Timer: FSB Clock    = %d\n", PcdGet32(PcdFSBClock)));
  49   DEBUG ((EFI_D_INFO, "Debug Timer: Divisor      = %d\n", ApicTimerDivisor));
  50   DEBUG ((EFI_D_INFO, "Debug Timer: Frequency    = %d\n", ApicTimerFrequency));
  51   DEBUG ((EFI_D_INFO, "Debug Timer: InitialCount = %d\n", InitialCount));
  52
  53   if (TimerFrequency != NULL) {
  54     *TimerFrequency = ApicTimerFrequency;
  55   }
  56   return InitialCount;
  57 }
  58
  59 /**
  60   Enable/Disable the interrupt of debug timer and return the interrupt state
  61   prior to the operation.
  62
  63   If EnableStatus is TRUE, enable the interrupt of debug timer.
  64   If EnableStatus is FALSE, disable the interrupt of debug timer.
  65
  66   @param[in] EnableStatus    Enable/Disable.
  67
  68   @retval TRUE  Debug timer interrupt were enabled on entry to this call.
  69   @retval FALSE Debug timer interrupt were disabled on entry to this call.
  70
  71 **/
  72 BOOLEAN
  73 EFIAPI
  74 SaveAndSetDebugTimerInterrupt (
  75   IN BOOLEAN                EnableStatus
  76   )
  77 {
  78   BOOLEAN     OldDebugTimerInterruptState;
  79
  80   OldDebugTimerInterruptState = GetApicTimerInterruptState ();
  81
  82   if (OldDebugTimerInterruptState != EnableStatus) {
  83     if (EnableStatus) {
  84       EnableApicTimerInterrupt ();
  85     } else {
  86       DisableApicTimerInterrupt ();
  87     }
  88     //
  89     // Validate the Debug Timer interrupt state
  90     // This will make additional delay after Local Apic Timer interrupt state is changed.
  91     // Thus, CPU could handle the potential pending interrupt of Local Apic timer.
  92     //
  93     while (GetApicTimerInterruptState () != EnableStatus) {
  94       CpuPause ();
  95     }
  96   }
  97
  98   return OldDebugTimerInterruptState;
  99 }
 100
 101 /**
 102   Check if the timer is time out.
 103
 104   @param[in] TimerCycle             Timer total count.
 105   @param[in] Timer                  The start timer from the begin.
 106   @param[in] TimeoutTicker          Ticker number need time out.
 107
 108   @return TRUE  Timer time out occurs.
 109   @retval FALSE Timer does not time out.
 110
 111 **/
 112 BOOLEAN
 113 IsDebugTimerTimeout (
 114   IN UINT32                     TimerCycle,
 115   IN UINT32                     Timer,
 116   IN UINT32                     TimeoutTicker
 117   )
 118 {
 119   UINT64  CurrentTimer;
 120   UINT64  Delta;
 121
 122   CurrentTimer = GetApicTimerCurrentCount ();
 123
 124   //
 125   // This timer counter counts down.  Check for roll over condition.
 126   //
 127   if (CurrentTimer < Timer) {
 128     Delta = Timer - CurrentTimer;
 129   } else {
 130     //
 131     // Handle one roll-over.
 132     //
 133     Delta = TimerCycle - (CurrentTimer - Timer);
 134   }
 135
 136   return (BOOLEAN) (Delta >= TimeoutTicker);
 137 }
 138