MdePkg/Library/SecPeiDxeTimerLibCpu/x86TimerLib.c

   1 /** @file
   2   Timer Library functions built upon local APIC on IA32/x64.
   3
   4   Copyright (c) 2006 - 2007, Intel Corporation<BR>
   5   All rights reserved. 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   Module Name:  x86TimerLib.c
  14
  15 **/
  16
  17 //
  18 // The following array is used in calculating the frequency of local APIC
  19 // timer. Refer to IA-32 developers' manual for more details.
  20 //
  21 GLOBAL_REMOVE_IF_UNREFERENCED
  22 CONST UINT8                           mTimerLibLocalApicDivisor[] = {
  23   0x02, 0x04, 0x08, 0x10,
  24   0x02, 0x04, 0x08, 0x10,
  25   0x20, 0x40, 0x80, 0x01,
  26   0x20, 0x40, 0x80, 0x01
  27 };
  28
  29 /**
  30   Internal function to retrieve the base address of local APIC.
  31
  32   Internal function to retrieve the base address of local APIC.
  33
  34   @return The base address of local APIC
  35
  36 **/
  37 STATIC
  38 UINTN
  39 InternalX86GetApicBase (
  40   VOID
  41   )
  42 {
  43   return (UINTN)AsmMsrBitFieldRead64 (27, 12, 35) << 12;
  44 }
  45
  46 /**
  47   Internal function to return the frequency of the local APIC timer.
  48
  49   Internal function to return the frequency of the local APIC timer.
  50
  51   @param  ApicBase  The base address of memory mapped registers of local APIC.
  52
  53   @return The frequency of the timer in Hz.
  54
  55 **/
  56 STATIC
  57 UINT32
  58 InternalX86GetTimerFrequency (
  59   IN      UINTN                     ApicBase
  60   )
  61 {
  62   return
  63     PcdGet32(PcdFSBClock) /
  64     mTimerLibLocalApicDivisor[MmioBitFieldRead32 (ApicBase + 0x3e0, 0, 3)];
  65 }
  66
  67 /**
  68   Internal function to read the current tick counter of local APIC.
  69
  70   Internal function to read the current tick counter of local APIC.
  71
  72   @param  ApicBase  The base address of memory mapped registers of local APIC.
  73
  74   @return The tick counter read.
  75
  76 **/
  77 STATIC
  78 INT32
  79 InternalX86GetTimerTick (
  80   IN      UINTN                     ApicBase
  81   )
  82 {
  83   return MmioRead32 (ApicBase + 0x390);
  84 }
  85
  86 /**
  87   Stalls the CPU for at least the given number of ticks.
  88
  89   Stalls the CPU for at least the given number of ticks. It's invoked by
  90   MicroSecondDelay() and NanoSecondDelay().
  91
  92   @param  ApicBase  The base address of memory mapped registers of local APIC.
  93   @param  Delay     A period of time to delay in ticks.
  94
  95 **/
  96 STATIC
  97 VOID
  98 InternalX86Delay (
  99   IN      UINTN                     ApicBase,
 100   IN      UINT32                    Delay
 101   )
 102 {
 103   INT32                             Ticks;
 104
 105   //
 106   // The target timer count is calculated here
 107   //
 108   Ticks = InternalX86GetTimerTick (ApicBase) - Delay;
 109
 110   //
 111   // Wait until time out
 112   // Delay > 2^31 could not be handled by this function
 113   // Timer wrap-arounds are handled correctly by this function
 114   //
 115   while (InternalX86GetTimerTick (ApicBase) - Ticks >= 0);
 116 }
 117
 118 /**
 119   Stalls the CPU for at least the given number of microseconds.
 120
 121   Stalls the CPU for the number of microseconds specified by MicroSeconds.
 122
 123   @param  MicroSeconds  The minimum number of microseconds to delay.
 124
 125   @return MicroSeconds
 126
 127 **/
 128 UINTN
 129 EFIAPI
 130 MicroSecondDelay (
 131   IN      UINTN                     MicroSeconds
 132   )
 133 {
 134   UINTN                             ApicBase;
 135
 136   ApicBase = InternalX86GetApicBase ();
 137   InternalX86Delay (
 138     ApicBase,
 139     (UINT32)DivU64x32 (
 140               MultU64x64 (
 141                 InternalX86GetTimerFrequency (ApicBase),
 142                 MicroSeconds
 143                 ),
 144               1000000u
 145               )
 146     );
 147   return MicroSeconds;
 148 }
 149
 150 /**
 151   Stalls the CPU for at least the given number of nanoseconds.
 152
 153   Stalls the CPU for the number of nanoseconds specified by NanoSeconds.
 154
 155   @param  NanoSeconds The minimum number of nanoseconds to delay.
 156
 157   @return NanoSeconds
 158
 159 **/
 160 UINTN
 161 EFIAPI
 162 NanoSecondDelay (
 163   IN      UINTN                     NanoSeconds
 164   )
 165 {
 166   UINTN                             ApicBase;
 167
 168   ApicBase = InternalX86GetApicBase ();
 169   InternalX86Delay (
 170     ApicBase,
 171     (UINT32)DivU64x32 (
 172               MultU64x64 (
 173                 InternalX86GetTimerFrequency (ApicBase),
 174                 NanoSeconds
 175                 ),
 176               1000000000u
 177               )
 178     );
 179   return NanoSeconds;
 180 }
 181
 182 /**
 183   Retrieves the current value of a 64-bit free running performance counter.
 184
 185   Retrieves the current value of a 64-bit free running performance counter. The
 186   counter can either count up by 1 or count down by 1. If the physical
 187   performance counter counts by a larger increment, then the counter values
 188   must be translated. The properties of the counter can be retrieved from
 189   GetPerformanceCounterProperties().
 190
 191   @return The current value of the free running performance counter.
 192
 193 **/
 194 UINT64
 195 EFIAPI
 196 GetPerformanceCounter (
 197   VOID
 198   )
 199 {
 200   return (UINT64)(UINT32)InternalX86GetTimerTick (InternalX86GetApicBase ());
 201 }
 202
 203 /**
 204   Retrieves the 64-bit frequency in Hz and the range of performance counter
 205   values.
 206
 207   If StartValue is not NULL, then the value that the performance counter starts
 208   with immediately after is it rolls over is returned in StartValue. If
 209   EndValue is not NULL, then the value that the performance counter end with
 210   immediately before it rolls over is returned in EndValue. The 64-bit
 211   frequency of the performance counter in Hz is always returned. If StartValue
 212   is less than EndValue, then the performance counter counts up. If StartValue
 213   is greater than EndValue, then the performance counter counts down. For
 214   example, a 64-bit free running counter that counts up would have a StartValue
 215   of 0 and an EndValue of 0xFFFFFFFFFFFFFFFF. A 24-bit free running counter
 216   that counts down would have a StartValue of 0xFFFFFF and an EndValue of 0.
 217
 218   @param  StartValue  The value the performance counter starts with when it
 219                       rolls over.
 220   @param  EndValue    The value that the performance counter ends with before
 221                       it rolls over.
 222
 223   @return The frequency in Hz.
 224
 225 **/
 226 UINT64
 227 EFIAPI
 228 GetPerformanceCounterProperties (
 229   OUT      UINT64                    *StartValue,  OPTIONAL
 230   OUT      UINT64                    *EndValue     OPTIONAL
 231   )
 232 {
 233   UINTN                             ApicBase;
 234
 235   ApicBase = InternalX86GetApicBase ();
 236
 237   if (StartValue != NULL) {
 238     *StartValue = MmioRead32 (ApicBase + 0x380);
 239   }
 240
 241   if (EndValue != NULL) {
 242     *EndValue = 0;
 243   }
 244
 245   return (UINT64) InternalX86GetTimerFrequency (ApicBase);;
 246 }