UefiCpuPkg/Library/SecPeiDxeTimerLibUefiCpu/X86TimerLib.c

   1 /** @file
   2   Timer Library functions built upon local APIC on IA32/x64.
   3
   4   This library uses the local APIC library so that it supports x2APIC mode.
   5
   6   Copyright (c) 2010 - 2013, Intel Corporation. All rights reserved.<BR>
   7   This program and the accompanying materials
   8   are licensed and made available under the terms and conditions of the BSD License
   9   which accompanies this distribution.  The full text of the license may be found at
  10   http://opensource.org/licenses/bsd-license.php.
  11
  12   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  13   WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  14
  15 **/
  16
  17 #include <Base.h>
  18 #include <Library/TimerLib.h>
  19 #include <Library/BaseLib.h>
  20 #include <Library/PcdLib.h>
  21 #include <Library/DebugLib.h>
  22 #include <Library/LocalApicLib.h>
  23
  24 /**
  25   Internal function to return the frequency of the local APIC timer.
  26
  27   @return The frequency of the timer in Hz.
  28
  29 **/
  30 UINT32
  31 EFIAPI
  32 InternalX86GetTimerFrequency (
  33   VOID
  34   )
  35 {
  36   UINTN Divisor;
  37
  38   GetApicTimerState (&Divisor, NULL, NULL);
  39   return PcdGet32(PcdFSBClock) / (UINT32)Divisor;
  40 }
  41
  42 /**
  43   Stalls the CPU for at least the given number of ticks.
  44
  45   Stalls the CPU for at least the given number of ticks. It's invoked by
  46   MicroSecondDelay() and NanoSecondDelay().
  47
  48   @param  Delay     A period of time to delay in ticks.
  49
  50 **/
  51 VOID
  52 EFIAPI
  53 InternalX86Delay (
  54   IN      UINT32                    Delay
  55   )
  56 {
  57   INT32                             Ticks;
  58   UINT32                            Times;
  59   UINT32                            InitCount;
  60   UINT32                            StartTick;
  61
  62   //
  63   // In case Delay is too larger, separate it into several small delay slot.
  64   // Devided Delay by half value of Init Count is to avoid Delay close to
  65   // the Init Count, timeout maybe missing if the time consuming between 2
  66   // GetApicTimerCurrentCount() invoking is larger than the time gap between
  67   // Delay and the Init Count.
  68   //
  69   InitCount = GetApicTimerInitCount ();
  70   Times     = Delay / (InitCount / 2);
  71   Delay     = Delay % (InitCount / 2);
  72
  73   //
  74   // Get Start Tick and do delay
  75   //
  76   StartTick  = GetApicTimerCurrentCount ();
  77   do {
  78     //
  79     // Wait until time out by Delay value
  80     //
  81     do {
  82       CpuPause ();
  83       //
  84       // Get Ticks from Start to Current.
  85       //
  86       Ticks = StartTick - GetApicTimerCurrentCount ();
  87       //
  88       // Ticks < 0 means Timer wrap-arounds happens.
  89       //
  90       if (Ticks < 0) {
  91         Ticks += InitCount;
  92       }
  93     } while ((UINT32)Ticks < Delay);
  94
  95     //
  96     // Update StartTick and Delay for next delay slot
  97     //
  98     StartTick -= (StartTick > Delay) ?  Delay : (Delay - InitCount);
  99     Delay      = InitCount / 2;
 100   } while (Times-- > 0);
 101 }
 102
 103 /**
 104   Stalls the CPU for at least the given number of microseconds.
 105
 106   Stalls the CPU for the number of microseconds specified by MicroSeconds.
 107
 108   @param  MicroSeconds  The minimum number of microseconds to delay.
 109
 110   @return The value of MicroSeconds inputted.
 111
 112 **/
 113 UINTN
 114 EFIAPI
 115 MicroSecondDelay (
 116   IN      UINTN                     MicroSeconds
 117   )
 118 {
 119   InternalX86Delay (
 120     (UINT32)DivU64x32 (
 121               MultU64x64 (
 122                 InternalX86GetTimerFrequency (),
 123                 MicroSeconds
 124                 ),
 125               1000000u
 126               )
 127     );
 128   return MicroSeconds;
 129 }
 130
 131 /**
 132   Stalls the CPU for at least the given number of nanoseconds.
 133
 134   Stalls the CPU for the number of nanoseconds specified by NanoSeconds.
 135
 136   @param  NanoSeconds The minimum number of nanoseconds to delay.
 137
 138   @return The value of NanoSeconds inputted.
 139
 140 **/
 141 UINTN
 142 EFIAPI
 143 NanoSecondDelay (
 144   IN      UINTN                     NanoSeconds
 145   )
 146 {
 147   InternalX86Delay (
 148     (UINT32)DivU64x32 (
 149               MultU64x64 (
 150                 InternalX86GetTimerFrequency (),
 151                 NanoSeconds
 152                 ),
 153               1000000000u
 154               )
 155     );
 156   return NanoSeconds;
 157 }
 158
 159 /**
 160   Retrieves the current value of a 64-bit free running performance counter.
 161
 162   The counter can either count up by 1 or count down by 1. If the physical
 163   performance counter counts by a larger increment, then the counter values
 164   must be translated. The properties of the counter can be retrieved from
 165   GetPerformanceCounterProperties().
 166
 167   @return The current value of the free running performance counter.
 168
 169 **/
 170 UINT64
 171 EFIAPI
 172 GetPerformanceCounter (
 173   VOID
 174   )
 175 {
 176   return (UINT64)GetApicTimerCurrentCount ();
 177 }
 178
 179 /**
 180   Retrieves the 64-bit frequency in Hz and the range of performance counter
 181   values.
 182
 183   If StartValue is not NULL, then the value that the performance counter starts
 184   with immediately after is it rolls over is returned in StartValue. If
 185   EndValue is not NULL, then the value that the performance counter end with
 186   immediately before it rolls over is returned in EndValue. The 64-bit
 187   frequency of the performance counter in Hz is always returned. If StartValue
 188   is less than EndValue, then the performance counter counts up. If StartValue
 189   is greater than EndValue, then the performance counter counts down. For
 190   example, a 64-bit free running counter that counts up would have a StartValue
 191   of 0 and an EndValue of 0xFFFFFFFFFFFFFFFF. A 24-bit free running counter
 192   that counts down would have a StartValue of 0xFFFFFF and an EndValue of 0.
 193
 194   @param  StartValue  The value the performance counter starts with when it
 195                       rolls over.
 196   @param  EndValue    The value that the performance counter ends with before
 197                       it rolls over.
 198
 199   @return The frequency in Hz.
 200
 201 **/
 202 UINT64
 203 EFIAPI
 204 GetPerformanceCounterProperties (
 205   OUT      UINT64                    *StartValue,  OPTIONAL
 206   OUT      UINT64                    *EndValue     OPTIONAL
 207   )
 208 {
 209   if (StartValue != NULL) {
 210     *StartValue = (UINT64)GetApicTimerInitCount ();
 211   }
 212
 213   if (EndValue != NULL) {
 214     *EndValue = 0;
 215   }
 216
 217   return (UINT64) InternalX86GetTimerFrequency ();
 218 }
 219
 220 /**
 221   Converts elapsed ticks of performance counter to time in nanoseconds.
 222
 223   This function converts the elapsed ticks of running performance counter to
 224   time value in unit of nanoseconds.
 225
 226   @param  Ticks     The number of elapsed ticks of running performance counter.
 227
 228   @return The elapsed time in nanoseconds.
 229
 230 **/
 231 UINT64
 232 EFIAPI
 233 GetTimeInNanoSecond (
 234   IN      UINT64                     Ticks
 235   )
 236 {
 237   UINT64  Frequency;
 238   UINT64  NanoSeconds;
 239   UINT64  Remainder;
 240   INTN    Shift;
 241
 242   Frequency = GetPerformanceCounterProperties (NULL, NULL);
 243
 244   //
 245   //          Ticks
 246   // Time = --------- x 1,000,000,000
 247   //        Frequency
 248   //
 249   NanoSeconds = MultU64x32 (DivU64x64Remainder (Ticks, Frequency, &Remainder), 1000000000u);
 250
 251   //
 252   // Ensure (Remainder * 1,000,000,000) will not overflow 64-bit.
 253   // Since 2^29 < 1,000,000,000 = 0x3B9ACA00 < 2^30, Remainder should < 2^(64-30) = 2^34,
 254   // i.e. highest bit set in Remainder should <= 33.
 255   //
 256   Shift = MAX (0, HighBitSet64 (Remainder) - 33);
 257   Remainder = RShiftU64 (Remainder, (UINTN) Shift);
 258   Frequency = RShiftU64 (Frequency, (UINTN) Shift);
 259   NanoSeconds += DivU64x64Remainder (MultU64x32 (Remainder, 1000000000u), Frequency, NULL);
 260
 261   return NanoSeconds;
 262 }