OvmfPkg/Library/AcpiTimerLib/AcpiTimerLib.c

   1 /** @file
   2   ACPI Timer implements one instance of Timer Library.
   3
   4   Copyright (c) 2008, Intel Corporation<BR> All rights
   5   reserved. This program and the accompanying materials are
   6   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/PciLib.h>
  20
  21 #define ACPI_TIMER_FREQUENCY   3579545
  22 #define ACPI_TIMER_COUNT_SIZE  0x01000000
  23
  24 /**
  25   The constructor function enables ACPI IO space.
  26
  27   If ACPI I/O space not enabled, this function will enable it.
  28   It will always return RETURN_SUCCESS.
  29
  30   @retval EFI_SUCCESS   The constructor always returns RETURN_SUCCESS.
  31
  32 **/
  33 RETURN_STATUS
  34 EFIAPI
  35 AcpiTimerLibConstructor (
  36   VOID
  37   )
  38 {
  39   UINT8 Device;
  40
  41   Device = 1;
  42   // Device = 7;
  43
  44   //
  45   // ACPI Timer enable is in Bus 0, Device ?, Function 3
  46   //
  47   PciOr8         (PCI_LIB_ADDRESS (0,Device,3,0x04), 0x01);
  48   PciAndThenOr32 (PCI_LIB_ADDRESS (0,Device,3,0x40), (UINT32) ~0xfc0, 0x400);
  49   PciOr8         (PCI_LIB_ADDRESS (0,Device,3,0x80), 0x01);  return RETURN_SUCCESS;
  50 }
  51
  52 /**
  53   Internal function to read the current tick counter of ACPI.
  54
  55   Internal function to read the current tick counter of ACPI.
  56
  57   @return The tick counter read.
  58
  59 **/
  60 STATIC
  61 UINT32
  62 InternalAcpiGetTimerTick (
  63   VOID
  64   )
  65 {
  66   return IoRead32 (0x408);
  67 }
  68
  69 /**
  70   Stalls the CPU for at least the given number of ticks.
  71
  72   Stalls the CPU for at least the given number of ticks. It's invoked by
  73   MicroSecondDelay() and NanoSecondDelay().
  74
  75   @param  Delay     A period of time to delay in ticks.
  76
  77 **/
  78 STATIC
  79 VOID
  80 InternalAcpiDelay (
  81   IN      UINT32                    Delay
  82   )
  83 {
  84   UINT32                            Ticks;
  85   UINT32                            Times;
  86
  87   Times    = Delay >> 22;
  88   Delay   &= BIT22 - 1;
  89   do {
  90     //
  91     // The target timer count is calculated here
  92     //
  93     Ticks    = InternalAcpiGetTimerTick () + Delay;
  94     Delay    = BIT22;
  95     //
  96     // Wait until time out
  97     // Delay >= 2^23 could not be handled by this function
  98     // Timer wrap-arounds are handled correctly by this function
  99     //
 100     while (((Ticks - InternalAcpiGetTimerTick ()) & BIT23) == 0) {
 101       CpuPause ();
 102     }
 103   } while (Times-- > 0);
 104 }
 105
 106 /**
 107   Stalls the CPU for at least the given number of microseconds.
 108
 109   Stalls the CPU for the number of microseconds specified by MicroSeconds.
 110
 111   @param  MicroSeconds  The minimum number of microseconds to delay.
 112
 113   @return MicroSeconds
 114
 115 **/
 116 UINTN
 117 EFIAPI
 118 MicroSecondDelay (
 119   IN      UINTN                     MicroSeconds
 120   )
 121 {
 122   InternalAcpiDelay (
 123     (UINT32)DivU64x32 (
 124               MultU64x32 (
 125                 MicroSeconds,
 126                 ACPI_TIMER_FREQUENCY
 127                 ),
 128               1000000u
 129               )
 130     );
 131   return MicroSeconds;
 132 }
 133
 134 /**
 135   Stalls the CPU for at least the given number of nanoseconds.
 136
 137   Stalls the CPU for the number of nanoseconds specified by NanoSeconds.
 138
 139   @param  NanoSeconds The minimum number of nanoseconds to delay.
 140
 141   @return NanoSeconds
 142
 143 **/
 144 UINTN
 145 EFIAPI
 146 NanoSecondDelay (
 147   IN      UINTN                     NanoSeconds
 148   )
 149 {
 150   InternalAcpiDelay (
 151     (UINT32)DivU64x32 (
 152               MultU64x32 (
 153                 NanoSeconds,
 154                 ACPI_TIMER_FREQUENCY
 155                 ),
 156               1000000000u
 157               )
 158     );
 159   return NanoSeconds;
 160 }
 161
 162 /**
 163   Retrieves the current value of a 64-bit free running performance counter.
 164
 165   Retrieves the current value of a 64-bit free running performance counter. The
 166   counter can either count up by 1 or count down by 1. If the physical
 167   performance counter counts by a larger increment, then the counter values
 168   must be translated. The properties of the counter can be retrieved from
 169   GetPerformanceCounterProperties().
 170
 171   @return The current value of the free running performance counter.
 172
 173 **/
 174 UINT64
 175 EFIAPI
 176 GetPerformanceCounter (
 177   VOID
 178   )
 179 {
 180   return (UINT64)InternalAcpiGetTimerTick ();
 181 }
 182
 183 /**
 184   Retrieves the 64-bit frequency in Hz and the range of performance counter
 185   values.
 186
 187   If StartValue is not NULL, then the value that the performance counter starts
 188   with immediately after is it rolls over is returned in StartValue. If
 189   EndValue is not NULL, then the value that the performance counter end with
 190   immediately before it rolls over is returned in EndValue. The 64-bit
 191   frequency of the performance counter in Hz is always returned. If StartValue
 192   is less than EndValue, then the performance counter counts up. If StartValue
 193   is greater than EndValue, then the performance counter counts down. For
 194   example, a 64-bit free running counter that counts up would have a StartValue
 195   of 0 and an EndValue of 0xFFFFFFFFFFFFFFFF. A 24-bit free running counter
 196   that counts down would have a StartValue of 0xFFFFFF and an EndValue of 0.
 197
 198   @param  StartValue  The value the performance counter starts with when it
 199                       rolls over.
 200   @param  EndValue    The value that the performance counter ends with before
 201                       it rolls over.
 202
 203   @return The frequency in Hz.
 204
 205 **/
 206 UINT64
 207 EFIAPI
 208 GetPerformanceCounterProperties (
 209   OUT      UINT64                    *StartValue,  OPTIONAL
 210   OUT      UINT64                    *EndValue     OPTIONAL
 211   )
 212 {
 213   if (StartValue != NULL) {
 214     *StartValue = 0;
 215   }
 216
 217   if (EndValue != NULL) {
 218     *EndValue = ACPI_TIMER_COUNT_SIZE - 1;
 219   }
 220
 221   return ACPI_TIMER_FREQUENCY;
 222 }