MdePkg/Library/BaseTimerLibLocalApic/x86TimerLib.c

   1 /** @file
   2   Timer Library functions built upon local APIC on IA32/x64.
   3
   4   @bug Should use PCD to retrieve all the constants including index of
   5   the IA32_APIC_BASE MSR, the offsets of InitialCount, CorrentCount
   6   and DivideConfiguration.
   7
   8   Copyright (c) 2006, Intel Corporation<BR>
   9   All rights reserved. This program and the accompanying materials
  10   are licensed and made available under the terms and conditions of the BSD License
  11   which accompanies this distribution.  The full text of the license may be found at
  12   http://opensource.org/licenses/bsd-license.php
  13
  14   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  15   WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  16
  17   Module Name:  x86TimerLib.c
  18
  19 **/
  20
  21 //
  22 // The following 2 arrays are used in calculating the frequency of local APIC
  23 // timer. Refer to IA-32 developers' manual for more details.
  24 //
  25
  26 GLOBAL_REMOVE_IF_UNREFERENCED
  27 CONST UINT32                          mTimerLibLocalApicFrequencies[] = {
  28   100000000,
  29   133000000,
  30   200000000,
  31   166000000
  32 };
  33
  34 GLOBAL_REMOVE_IF_UNREFERENCED
  35 CONST UINT8                           mTimerLibLocalApicDivisor[] = {
  36   0x02, 0x04, 0x08, 0x10,
  37   0x02, 0x04, 0x08, 0x10,
  38   0x20, 0x40, 0x80, 0x01,
  39   0x20, 0x40, 0x80, 0x01
  40 };
  41
  42 /**
  43   Internal function to retrieve the base address of local APIC.
  44
  45   Internal function to retrieve the base address of local APIC.
  46
  47   @return The base address of local APIC
  48
  49 **/
  50 STATIC
  51 UINTN
  52 InternalX86GetApicBase (
  53   VOID
  54   )
  55 {
  56   return (UINTN)AsmMsrBitFieldRead64 (27, 12, 35) << 12;
  57 }
  58
  59 /**
  60   Internal function to return the frequency of the local APIC timer.
  61
  62   Internal function to return the frequency of the local APIC timer.
  63
  64   @param  ApicBase  The base address of memory mapped registers of local APIC.
  65
  66   @return The frequency of the timer in Hz.
  67
  68 **/
  69 STATIC
  70 UINT32
  71 InternalX86GetTimerFrequency (
  72   IN      UINTN                     ApicBase
  73   )
  74 {
  75   return
  76     mTimerLibLocalApicFrequencies[AsmMsrBitFieldRead32 (44, 16, 18)] /
  77     mTimerLibLocalApicDivisor[MmioBitFieldRead32 (ApicBase + 0x3e0, 0, 3)];
  78 }
  79
  80 /**
  81   Internal function to read the current tick counter of local APIC.
  82
  83   Internal function to read the current tick counter of local APIC.
  84
  85   @param  ApicBase  The base address of memory mapped registers of local APIC.
  86
  87   @return The tick counter read.
  88
  89 **/
  90 STATIC
  91 INT32
  92 InternalX86GetTimerTick (
  93   IN      UINTN                     ApicBase
  94   )
  95 {
  96   return MmioRead32 (ApicBase + 0x390);
  97 }
  98
  99 /**
 100   Stalls the CPU for at least the given number of ticks.
 101
 102   Stalls the CPU for at least the given number of ticks. It's invoked by
 103   MicroSecondDelay() and NanoSecondDelay().
 104
 105   @param  ApicBase  The base address of memory mapped registers of local APIC.
 106   @param  Delay     A period of time to delay in ticks.
 107
 108 **/
 109 STATIC
 110 VOID
 111 InternalX86Delay (
 112   IN      UINTN                     ApicBase,
 113   IN      UINT32                    Delay
 114   )
 115 {
 116   INT32                             Ticks;
 117
 118   //
 119   // The target timer count is calculated here
 120   //
 121   Ticks = InternalX86GetTimerTick (ApicBase) - Delay;
 122
 123   //
 124   // Wait until time out
 125   // Delay > 2^31 could not be handled by this function
 126   // Timer wrap-arounds are handled correctly by this function
 127   //
 128   while (InternalX86GetTimerTick (ApicBase) - Ticks >= 0);
 129 }
 130
 131 /**
 132   Stalls the CPU for at least the given number of microseconds.
 133
 134   Stalls the CPU for the number of microseconds specified by MicroSeconds.
 135
 136   @param  MicroSeconds  The minimum number of microseconds to delay.
 137
 138   @return MicroSeconds
 139
 140 **/
 141 UINTN
 142 EFIAPI
 143 MicroSecondDelay (
 144   IN      UINTN                     MicroSeconds
 145   )
 146 {
 147   UINTN                             ApicBase;
 148
 149   ApicBase = InternalX86GetApicBase ();
 150   InternalX86Delay (
 151     ApicBase,
 152     (UINT32)DivU64x32 (
 153               MultU64x64 (
 154                 InternalX86GetTimerFrequency (ApicBase),
 155                 MicroSeconds
 156                 ),
 157               1000000u
 158               )
 159     );
 160   return MicroSeconds;
 161 }
 162
 163 /**
 164   Stalls the CPU for at least the given number of nanoseconds.
 165
 166   Stalls the CPU for the number of nanoseconds specified by NanoSeconds.
 167
 168   @param  NanoSeconds The minimum number of nanoseconds to delay.
 169
 170   @return NanoSeconds
 171
 172 **/
 173 UINTN
 174 EFIAPI
 175 NanoSecondDelay (
 176   IN      UINTN                     NanoSeconds
 177   )
 178 {
 179   UINTN                             ApicBase;
 180
 181   ApicBase = InternalX86GetApicBase ();
 182   InternalX86Delay (
 183     ApicBase,
 184     (UINT32)DivU64x32 (
 185               MultU64x64 (
 186                 InternalX86GetTimerFrequency (ApicBase),
 187                 NanoSeconds
 188                 ),
 189               1000000000u
 190               )
 191     );
 192   return NanoSeconds;
 193 }
 194
 195 /**
 196   Retrieves the current value of a 64-bit free running performance counter.
 197
 198   Retrieves the current value of a 64-bit free running performance counter. The
 199   counter can either count up by 1 or count down by 1. If the physical
 200   performance counter counts by a larger increment, then the counter values
 201   must be translated. The properties of the counter can be retrieved from
 202   GetPerformanceCounterProperties().
 203
 204   @return The current value of the free running performance counter.
 205
 206 **/
 207 UINT64
 208 EFIAPI
 209 GetPerformanceCounter (
 210   VOID
 211   )
 212 {
 213   return (UINT64)(UINT32)InternalX86GetTimerTick (InternalX86GetApicBase ());
 214 }
 215
 216 /**
 217   Retrieves the 64-bit frequency in Hz and the range of performance counter
 218   values.
 219
 220   If StartValue is not NULL, then the value that the performance counter starts
 221   with immediately after is it rolls over is returned in StartValue. If
 222   EndValue is not NULL, then the value that the performance counter end with
 223   immediately before it rolls over is returned in EndValue. The 64-bit
 224   frequency of the performance counter in Hz is always returned. If StartValue
 225   is less than EndValue, then the performance counter counts up. If StartValue
 226   is greater than EndValue, then the performance counter counts down. For
 227   example, a 64-bit free running counter that counts up would have a StartValue
 228   of 0 and an EndValue of 0xFFFFFFFFFFFFFFFF. A 24-bit free running counter
 229   that counts down would have a StartValue of 0xFFFFFF and an EndValue of 0.
 230
 231   @param  StartValue  The value the performance counter starts with when it
 232                       rolls over.
 233   @param  EndValue    The value that the performance counter ends with before
 234                       it rolls over.
 235
 236   @return The frequency in Hz.
 237
 238 **/
 239 UINT64
 240 EFIAPI
 241 GetPerformanceCounterProperties (
 242   OUT      UINT64                    *StartValue,  OPTIONAL
 243   OUT      UINT64                    *EndValue     OPTIONAL
 244   )
 245 {
 246   UINTN                             ApicBase;
 247
 248   ApicBase = InternalX86GetApicBase ();
 249
 250   if (StartValue != NULL) {
 251     *StartValue = MmioRead32 (ApicBase + 0x380);
 252   }
 253
 254   if (EndValue != NULL) {
 255     *EndValue = 0;
 256   }
 257
 258   return (UINT64)InternalX86GetTimerFrequency (ApicBase);
 259 }