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   SPDX-License-Identifier: BSD-2-Clause-Patent
   6
   7 **/
   8
   9 #include "DebugAgent.h"
  10
  11 /**
  12   Initialize CPU local APIC timer.
  13
  14   @param[out] TimerFrequency  Local APIC timer frequency returned.
  15   @param[in]  DumpFlag        If TRUE, dump Local APIC timer's parameter.
  16
  17   @return   32-bit Local APIC timer init count.
  18 **/
  19 UINT32
  20 InitializeDebugTimer (
  21   OUT UINT32   *TimerFrequency,
  22   IN  BOOLEAN  DumpFlag
  23   )
  24 {
  25   UINTN   ApicTimerDivisor;
  26   UINT32  InitialCount;
  27   UINT32  ApicTimerFrequency;
  28
  29   InitializeLocalApicSoftwareEnable (TRUE);
  30   GetApicTimerState (&ApicTimerDivisor, NULL, NULL);
  31   ApicTimerFrequency = PcdGet32 (PcdFSBClock) / (UINT32)ApicTimerDivisor;
  32   //
  33   // Cpu Local Apic timer interrupt frequency, it is set to 0.1s
  34   //
  35   InitialCount = (UINT32)DivU64x32 (
  36                            MultU64x64 (
  37                              ApicTimerFrequency,
  38                              DEBUG_TIMER_INTERVAL
  39                              ),
  40                            1000000u
  41                            );
  42
  43   InitializeApicTimer (ApicTimerDivisor, InitialCount, TRUE, DEBUG_TIMER_VECTOR);
  44   //
  45   // Disable Debug Timer interrupt to avoid it is delivered before Debug Port
  46   // is initialized
  47   //
  48   DisableApicTimerInterrupt ();
  49
  50   if (DumpFlag) {
  51     DEBUG ((DEBUG_INFO, "Debug Timer: FSB Clock    = %d\n", PcdGet32 (PcdFSBClock)));
  52     DEBUG ((DEBUG_INFO, "Debug Timer: Divisor      = %d\n", ApicTimerDivisor));
  53     DEBUG ((DEBUG_INFO, "Debug Timer: Frequency    = %d\n", ApicTimerFrequency));
  54     DEBUG ((DEBUG_INFO, "Debug Timer: InitialCount = %d\n", InitialCount));
  55   }
  56
  57   if (TimerFrequency != NULL) {
  58     *TimerFrequency = ApicTimerFrequency;
  59   }
  60
  61   return InitialCount;
  62 }
  63
  64 /**
  65   Enable/Disable the interrupt of debug timer and return the interrupt state
  66   prior to the operation.
  67
  68   If EnableStatus is TRUE, enable the interrupt of debug timer.
  69   If EnableStatus is FALSE, disable the interrupt of debug timer.
  70
  71   @param[in] EnableStatus    Enable/Disable.
  72
  73   @retval TRUE  Debug timer interrupt were enabled on entry to this call.
  74   @retval FALSE Debug timer interrupt were disabled on entry to this call.
  75
  76 **/
  77 BOOLEAN
  78 EFIAPI
  79 SaveAndSetDebugTimerInterrupt (
  80   IN BOOLEAN  EnableStatus
  81   )
  82 {
  83   BOOLEAN  OldDebugTimerInterruptState;
  84
  85   OldDebugTimerInterruptState = GetApicTimerInterruptState ();
  86
  87   if (OldDebugTimerInterruptState != EnableStatus) {
  88     if (EnableStatus) {
  89       EnableApicTimerInterrupt ();
  90     } else {
  91       DisableApicTimerInterrupt ();
  92     }
  93
  94     //
  95     // Validate the Debug Timer interrupt state
  96     // This will make additional delay after Local Apic Timer interrupt state is changed.
  97     // Thus, CPU could handle the potential pending interrupt of Local Apic timer.
  98     //
  99     while (GetApicTimerInterruptState () != EnableStatus) {
 100       CpuPause ();
 101     }
 102   }
 103
 104   return OldDebugTimerInterruptState;
 105 }
 106
 107 /**
 108   Check if the timer is time out.
 109
 110   @param[in] TimerCycle             Timer initial count.
 111   @param[in] Timer                  The start timer from the begin.
 112   @param[in] TimeoutTicker          Ticker number need time out.
 113
 114   @return TRUE  Timer time out occurs.
 115   @retval FALSE Timer does not time out.
 116
 117 **/
 118 BOOLEAN
 119 IsDebugTimerTimeout (
 120   IN UINT32  TimerCycle,
 121   IN UINT32  Timer,
 122   IN UINT32  TimeoutTicker
 123   )
 124 {
 125   UINT64  CurrentTimer;
 126   UINT64  Delta;
 127
 128   CurrentTimer = GetApicTimerCurrentCount ();
 129
 130   //
 131   // This timer counter counts down.  Check for roll over condition.
 132   // If CurrentTimer is equal to Timer, it does not mean that roll over
 133   // happened.
 134   //
 135   if (CurrentTimer <= Timer) {
 136     Delta = Timer - CurrentTimer;
 137   } else {
 138     //
 139     // Handle one roll-over.
 140     //
 141     Delta = TimerCycle - (CurrentTimer - Timer) + 1;
 142   }
 143
 144   return (BOOLEAN)(Delta >= TimeoutTicker);
 145 }