DuetPkg/Library/DuetTimerLib/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 **/
  14
  15 #include <Base.h>
  16 #include <Library/TimerLib.h>
  17 #include <Library/BaseLib.h>
  18 #include <Library/IoLib.h>
  19 #include <Library/DebugLib.h>
  20 #include <Library/PcdLib.h>
  21
  22
  23 //
  24 // The following array is used in calculating the frequency of local APIC
  25 // timer. Refer to IA-32 developers' manual for more details.
  26 //
  27 GLOBAL_REMOVE_IF_UNREFERENCED
  28 CONST UINT8                           mTimerLibLocalApicDivisor[] = {
  29   0x02, 0x04, 0x08, 0x10,
  30   0x02, 0x04, 0x08, 0x10,
  31   0x20, 0x40, 0x80, 0x01,
  32   0x20, 0x40, 0x80, 0x01
  33 };
  34
  35 /**
  36   Internal function to retrieve the base address of local APIC.
  37
  38   Internal function to retrieve the base address of local APIC.
  39
  40   @return The base address of local APIC
  41
  42 **/
  43 STATIC
  44 UINTN
  45 InternalX86GetApicBase (
  46   VOID
  47   )
  48 {
  49   return (UINTN)AsmMsrBitFieldRead64 (27, 12, 35) << 12;
  50 }
  51
  52 /**
  53   Internal function to return the frequency of the local APIC timer.
  54
  55   Internal function to return the frequency of the local APIC timer.
  56
  57   @param  ApicBase  The base address of memory mapped registers of local APIC.
  58
  59   @return The frequency of the timer in Hz.
  60
  61 **/
  62 STATIC
  63 UINT32
  64 InternalX86GetTimerFrequency (
  65   IN      UINTN                     ApicBase
  66   )
  67 {
  68   return
  69     PcdGet32(PcdFSBClock) /
  70     mTimerLibLocalApicDivisor[MmioBitFieldRead32 (ApicBase + 0x3e0, 0, 3)];
  71 }
  72
  73 /**
  74   Internal function to read the current tick counter of local APIC.
  75
  76   Internal function to read the current tick counter of local APIC.
  77
  78   @param  ApicBase  The base address of memory mapped registers of local APIC.
  79
  80   @return The tick counter read.
  81
  82 **/
  83 STATIC
  84 INT32
  85 InternalX86GetTimerTick (
  86   IN      UINTN                     ApicBase
  87   )
  88 {
  89   return MmioRead32 (ApicBase + 0x390);
  90 }
  91
  92 /**
  93   Stalls the CPU for at least the given number of ticks.
  94
  95   Stalls the CPU for at least the given number of ticks. It's invoked by
  96   MicroSecondDelay() and NanoSecondDelay().
  97
  98   @param  ApicBase  The base address of memory mapped registers of local APIC.
  99   @param  Delay     A period of time to delay in ticks.
 100
 101 **/
 102 STATIC
 103 VOID
 104 InternalX86Delay (
 105   IN      UINTN                     ApicBase,
 106   IN      UINT32                    Delay
 107   )
 108 {
 109   INT32                             Ticks;
 110
 111   //
 112   // The target timer count is calculated here
 113   //
 114   Ticks = InternalX86GetTimerTick (ApicBase) - Delay;
 115
 116   //
 117   // Wait until time out
 118   // Delay > 2^31 could not be handled by this function
 119   // Timer wrap-arounds are handled correctly by this function
 120   //
 121   while (InternalX86GetTimerTick (ApicBase) - Ticks >= 0);
 122 }
 123
 124 /**
 125   Stalls the CPU for at least the given number of microseconds.
 126
 127   Stalls the CPU for the number of microseconds specified by MicroSeconds.
 128
 129   @param  MicroSeconds  The minimum number of microseconds to delay.
 130
 131   @return MicroSeconds
 132
 133 **/
 134 UINTN
 135 EFIAPI
 136 MicroSecondDelay (
 137   IN      UINTN                     MicroSeconds
 138   )
 139 {
 140   UINTN                             ApicBase;
 141
 142   ApicBase = InternalX86GetApicBase ();
 143   InternalX86Delay (
 144     ApicBase,
 145     (UINT32)DivU64x32 (
 146               MultU64x64 (
 147                 InternalX86GetTimerFrequency (ApicBase),
 148                 MicroSeconds
 149                 ),
 150               1000000u
 151               )
 152     );
 153   return MicroSeconds;
 154 }
 155
 156 /**
 157   Stalls the CPU for at least the given number of nanoseconds.
 158
 159   Stalls the CPU for the number of nanoseconds specified by NanoSeconds.
 160
 161   @param  NanoSeconds The minimum number of nanoseconds to delay.
 162
 163   @return NanoSeconds
 164
 165 **/
 166 UINTN
 167 EFIAPI
 168 NanoSecondDelay (
 169   IN      UINTN                     NanoSeconds
 170   )
 171 {
 172   UINTN                             ApicBase;
 173
 174   ApicBase = InternalX86GetApicBase ();
 175   InternalX86Delay (
 176     ApicBase,
 177     (UINT32)DivU64x32 (
 178               MultU64x64 (
 179                 InternalX86GetTimerFrequency (ApicBase),
 180                 NanoSeconds
 181                 ),
 182               1000000000u
 183               )
 184     );
 185   return NanoSeconds;
 186 }
 187
 188 /**
 189   Retrieves the current value of a 64-bit free running performance counter.
 190
 191   Retrieves the current value of a 64-bit free running performance counter. The
 192   counter can either count up by 1 or count down by 1. If the physical
 193   performance counter counts by a larger increment, then the counter values
 194   must be translated. The properties of the counter can be retrieved from
 195   GetPerformanceCounterProperties().
 196
 197   @return The current value of the free running performance counter.
 198
 199 **/
 200 UINT64
 201 EFIAPI
 202 GetPerformanceCounter (
 203   VOID
 204   )
 205 {
 206   return (UINT64)(UINT32)InternalX86GetTimerTick (InternalX86GetApicBase ());
 207 }
 208
 209 /**
 210   Retrieves the 64-bit frequency in Hz and the range of performance counter
 211   values.
 212
 213   If StartValue is not NULL, then the value that the performance counter starts
 214   with immediately after is it rolls over is returned in StartValue. If
 215   EndValue is not NULL, then the value that the performance counter end with
 216   immediately before it rolls over is returned in EndValue. The 64-bit
 217   frequency of the performance counter in Hz is always returned. If StartValue
 218   is less than EndValue, then the performance counter counts up. If StartValue
 219   is greater than EndValue, then the performance counter counts down. For
 220   example, a 64-bit free running counter that counts up would have a StartValue
 221   of 0 and an EndValue of 0xFFFFFFFFFFFFFFFF. A 24-bit free running counter
 222   that counts down would have a StartValue of 0xFFFFFF and an EndValue of 0.
 223
 224   @param  StartValue  The value the performance counter starts with when it
 225                       rolls over.
 226   @param  EndValue    The value that the performance counter ends with before
 227                       it rolls over.
 228
 229   @return The frequency in Hz.
 230
 231 **/
 232 UINT64
 233 EFIAPI
 234 GetPerformanceCounterProperties (
 235   OUT      UINT64                    *StartValue,  OPTIONAL
 236   OUT      UINT64                    *EndValue     OPTIONAL
 237   )
 238 {
 239   UINTN                             ApicBase;
 240
 241   ApicBase = InternalX86GetApicBase ();
 242
 243   if (StartValue != NULL) {
 244     *StartValue = MmioRead32 (ApicBase + 0x380);
 245   }
 246
 247   if (EndValue != NULL) {
 248     *EndValue = 0;
 249   }
 250
 251   return (UINT64) InternalX86GetTimerFrequency (ApicBase);;
 252 }