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