MdePkg/Library/DxeTimerLibEsal/DxeTimerLibEsal.c

   1 /** @file
   2   This library implements the Timer Library using the Extended SAL Stall Services Class.
   3
   4   Copyright (c) 2007 - 2011, 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 <PiDxe.h>
  16
  17 #include <Protocol/ExtendedSalServiceClasses.h>
  18
  19 #include <Library/TimerLib.h>
  20 #include <Library/BaseLib.h>
  21 #include <Library/ExtendedSalLib.h>
  22 #include <Library/DebugLib.h>
  23 #include <Library/PalLib.h>
  24
  25 /**
  26   Stalls the CPU for at least the given number of microseconds.
  27
  28   This function wraps EsalStall function of Extended SAL Stall Services Class.
  29   It stalls the CPU for the number of microseconds specified by MicroSeconds.
  30
  31   @param  MicroSeconds  The minimum number of microseconds to delay.
  32
  33   @return MicroSeconds
  34
  35 **/
  36 UINTN
  37 EFIAPI
  38 MicroSecondDelay (
  39   IN      UINTN                     MicroSeconds
  40   )
  41 {
  42   EsalCall (
  43     EFI_EXTENDED_SAL_STALL_SERVICES_PROTOCOL_GUID_LO,
  44     EFI_EXTENDED_SAL_STALL_SERVICES_PROTOCOL_GUID_HI,
  45     StallFunctionId,
  46     MicroSeconds,
  47     0,
  48     0,
  49     0,
  50     0,
  51     0,
  52     0
  53     );
  54   return MicroSeconds;
  55 }
  56
  57 /**
  58   Stalls the CPU for at least the given number of nanoseconds.
  59
  60   This function wraps EsalStall function of Extended SAL Stall Services Class.
  61   It stalls the CPU for the number of nanoseconds specified by NanoSeconds.
  62
  63   @param  NanoSeconds The minimum number of nanoseconds to delay.
  64
  65   @return NanoSeconds
  66
  67 **/
  68 UINTN
  69 EFIAPI
  70 NanoSecondDelay (
  71   IN      UINTN                     NanoSeconds
  72   )
  73 {
  74   UINT64          MicroSeconds;
  75
  76   //
  77   // The unit of ESAL Stall service is microsecond, so we turn the time interval
  78   // from nanosecond to microsecond, using the ceiling value to ensure stalling
  79   // at least the given number of nanoseconds.
  80   //
  81   MicroSeconds = DivU64x32 (NanoSeconds + 999, 1000);
  82   EsalCall (
  83     EFI_EXTENDED_SAL_STALL_SERVICES_PROTOCOL_GUID_LO,
  84     EFI_EXTENDED_SAL_STALL_SERVICES_PROTOCOL_GUID_HI,
  85     StallFunctionId,
  86     MicroSeconds,
  87     0,
  88     0,
  89     0,
  90     0,
  91     0,
  92     0
  93     );
  94   return NanoSeconds;
  95 }
  96
  97 /**
  98   Retrieves the current value of a 64-bit free running performance counter.
  99
 100   Retrieves the current value of a 64-bit free running performance counter. The
 101   counter can either count up by 1 or count down by 1. If the physical
 102   performance counter counts by a larger increment, then the counter values
 103   must be translated. The properties of the counter can be retrieved from
 104   GetPerformanceCounterProperties().
 105
 106   @return The current value of the free running performance counter.
 107
 108 **/
 109 UINT64
 110 EFIAPI
 111 GetPerformanceCounter (
 112   VOID
 113   )
 114 {
 115   return AsmReadItc ();
 116 }
 117
 118 /**
 119   Retrieves the 64-bit frequency in Hz and the range of performance counter
 120   values.
 121
 122   If StartValue is not NULL, then the value that the performance counter starts
 123   with immediately after is it rolls over is returned in StartValue. If
 124   EndValue is not NULL, then the value that the performance counter end with
 125   immediately before it rolls over is returned in EndValue. The 64-bit
 126   frequency of the performance counter in Hz is always returned. If StartValue
 127   is less than EndValue, then the performance counter counts up. If StartValue
 128   is greater than EndValue, then the performance counter counts down. For
 129   example, a 64-bit free running counter that counts up would have a StartValue
 130   of 0 and an EndValue of 0xFFFFFFFFFFFFFFFF. A 24-bit free running counter
 131   that counts down would have a StartValue of 0xFFFFFF and an EndValue of 0.
 132
 133   @param  StartValue  The value the performance counter starts with when it
 134                       rolls over.
 135   @param  EndValue    The value that the performance counter ends with before
 136                       it rolls over.
 137
 138   @return The frequency in Hz.
 139
 140 **/
 141 UINT64
 142 EFIAPI
 143 GetPerformanceCounterProperties (
 144   OUT      UINT64                    *StartValue,  OPTIONAL
 145   OUT      UINT64                    *EndValue     OPTIONAL
 146   )
 147 {
 148   PAL_CALL_RETURN                   PalRet;
 149   UINT64                            BaseFrequence;
 150
 151   //
 152   // Get processor base frequency
 153   //
 154   PalRet = PalCall (PAL_FREQ_BASE, 0, 0, 0);
 155   ASSERT (PalRet.Status == 0);
 156   BaseFrequence = PalRet.r9;
 157
 158   //
 159   // Get processor frequency ratio
 160   //
 161   PalRet = PalCall (PAL_FREQ_RATIOS, 0, 0, 0);
 162   ASSERT (PalRet.Status == 0);
 163
 164   //
 165   // Start value of counter is 0
 166   //
 167   if (StartValue != NULL) {
 168     *StartValue = 0;
 169   }
 170
 171   //
 172   // End value of counter is 0xFFFFFFFFFFFFFFFF
 173   //
 174   if (EndValue != NULL) {
 175     *EndValue = (UINT64)(-1);
 176   }
 177
 178   return BaseFrequence * (PalRet.r11 >> 32) / (UINT32)PalRet.r11;
 179 }
 180
 181 /**
 182   Converts elapsed ticks of performance counter to time in nanoseconds.
 183
 184   This function converts the elapsed ticks of running performance counter to
 185   time value in unit of nanoseconds.
 186
 187   @param  Ticks     The number of elapsed ticks of running performance counter.
 188
 189   @return The elapsed time in nanoseconds.
 190
 191 **/
 192 UINT64
 193 EFIAPI
 194 GetTimeInNanoSecond (
 195   IN      UINT64                     Ticks
 196   )
 197 {
 198   UINT64  Frequency;
 199   UINT64  NanoSeconds;
 200   UINT64  Remainder;
 201   INTN    Shift;
 202
 203   Frequency = GetPerformanceCounterProperties (NULL, NULL);
 204
 205   //
 206   //          Ticks
 207   // Time = --------- x 1,000,000,000
 208   //        Frequency
 209   //
 210   NanoSeconds = MultU64x32 (DivU64x64Remainder (Ticks, Frequency, &Remainder), 1000000000u);
 211
 212   //
 213   // Ensure (Remainder * 1,000,000,000) will not overflow 64-bit.
 214   // Since 2^29 < 1,000,000,000 = 0x3B9ACA00 < 2^30, Remainder should < 2^(64-30) = 2^34,
 215   // i.e. highest bit set in Remainder should <= 33.
 216   //
 217   Shift = MAX (0, HighBitSet64 (Remainder) - 33);
 218   Remainder = RShiftU64 (Remainder, (UINTN) Shift);
 219   Frequency = RShiftU64 (Frequency, (UINTN) Shift);
 220   NanoSeconds += DivU64x64Remainder (MultU64x32 (Remainder, 1000000000u), Frequency, NULL);
 221
 222   return NanoSeconds;
 223 }