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   ApicBase = InternalX86GetApicBase ();
 119
 120   //
 121   // The target timer count is calculated here
 122   //
 123   Ticks = InternalX86GetTimerTick (ApicBase) - Delay;
 124
 125   //
 126   // Wait until time out
 127   // Delay > 2^31 could not be handled by this function
 128   // Timer wrap-arounds are handled correctly by this function
 129   //
 130   while (InternalX86GetTimerTick (ApicBase) - Ticks >= 0);
 131 }
 132
 133 /**
 134   Stalls the CPU for at least the given number of microseconds.
 135
 136   Stalls the CPU for the number of microseconds specified by MicroSeconds.
 137
 138   @param  MicroSeconds  The minimum number of microseconds to delay.
 139
 140   @return MicroSeconds
 141
 142 **/
 143 UINTN
 144 EFIAPI
 145 MicroSecondDelay (
 146   IN      UINTN                     MicroSeconds
 147   )
 148 {
 149   UINTN                             ApicBase;
 150
 151   ApicBase = InternalX86GetApicBase ();
 152   InternalX86Delay (
 153     ApicBase,
 154     (UINT32)DivU64x32 (
 155               MultU64x64 (
 156                 InternalX86GetTimerFrequency (ApicBase),
 157                 MicroSeconds
 158                 ),
 159               1000000u
 160               )
 161     );
 162   return MicroSeconds;
 163 }
 164
 165 /**
 166   Stalls the CPU for at least the given number of nanoseconds.
 167
 168   Stalls the CPU for the number of nanoseconds specified by NanoSeconds.
 169
 170   @param  NanoSeconds The minimum number of nanoseconds to delay.
 171
 172   @return NanoSeconds
 173
 174 **/
 175 UINTN
 176 EFIAPI
 177 NanoSecondDelay (
 178   IN      UINTN                     NanoSeconds
 179   )
 180 {
 181   UINTN                             ApicBase;
 182
 183   ApicBase = InternalX86GetApicBase ();
 184   InternalX86Delay (
 185     ApicBase,
 186     (UINT32)DivU64x32 (
 187               MultU64x64 (
 188                 InternalX86GetTimerFrequency (ApicBase),
 189                 NanoSeconds
 190                 ),
 191               1000000000u
 192               )
 193     );
 194   return NanoSeconds;
 195 }
 196
 197 /**
 198   Retrieves the current value of a 64-bit free running performance counter.
 199
 200   Retrieves the current value of a 64-bit free running performance counter. The
 201   counter can either count up by 1 or count down by 1. If the physical
 202   performance counter counts by a larger increment, then the counter values
 203   must be translated. The properties of the counter can be retrieved from
 204   GetPerformanceCounterProperties().
 205
 206   @return The current value of the free running performance counter.
 207
 208 **/
 209 UINT64
 210 EFIAPI
 211 GetPerformanceCounter (
 212   VOID
 213   )
 214 {
 215   return InternalX86GetTimerTick (InternalX86GetApicBase ());
 216 }
 217
 218 /**
 219   Retrieves the 64-bit frequency in Hz and the range of performance counter
 220   values.
 221
 222   If StartValue is not NULL, then the value that the performance counter starts
 223   with immediately after is it rolls over is returned in StartValue. If
 224   EndValue is not NULL, then the value that the performance counter end with
 225   immediately before it rolls over is returned in EndValue. The 64-bit
 226   frequency of the performance counter in Hz is always returned. If StartValue
 227   is less than EndValue, then the performance counter counts up. If StartValue
 228   is greater than EndValue, then the performance counter counts down. For
 229   example, a 64-bit free running counter that counts up would have a StartValue
 230   of 0 and an EndValue of 0xFFFFFFFFFFFFFFFF. A 24-bit free running counter
 231   that counts down would have a StartValue of 0xFFFFFF and an EndValue of 0.
 232
 233   @param  StartValue  The value the performance counter starts with when it
 234                       rolls over.
 235   @param  EndValue    The value that the performance counter ends with before
 236                       it rolls over.
 237
 238   @return The frequency in Hz.
 239
 240 **/
 241 UINT64
 242 EFIAPI
 243 GetPerformanceCounterProperties (
 244   IN      UINT64                    *StartValue,
 245   IN      UINT64                    *EndValue
 246   )
 247 {
 248   UINTN                             ApicBase;
 249
 250   ApicBase = InternalX86GetApicBase ();
 251
 252   if (StartValue != NULL) {
 253     *StartValue = MmioRead32 (ApicBase + 0x380);
 254   }
 255
 256   if (EndValue != NULL) {
 257     *EndValue = 0;
 258   }
 259
 260   return InternalX86GetTimerFrequency (ApicBase);
 261 }