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