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      1 /*++
      2 
      3 Copyright (c) 2004 - 2006, Intel Corporation. All rights reserved.<BR>
      4 This program and the accompanying materials
      5 are licensed and made available under the terms and conditions of the BSD License
      6 which accompanies this distribution.  The full text of the license may be found at
      7 http://opensource.org/licenses/bsd-license.php
      8 
      9 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
     10 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
     11 
     12 
     13 Module Name:
     14 
     15   IpfTimerLib.c
     16 
     17 Abstract:
     18 
     19   Timer Library functions built upon local APIC on IA32/x64.
     20 
     21   @bug Should use PCD to retrieve all the constants including index of
     22   the IA32_APIC_BASE MSR, the offsets of InitialCount, CorrentCount
     23   and DivideConfiguration.
     24 
     25 --*/
     26 
     27 #include "EdkIIGlueBase.h"
     28 
     29 
     30 /**
     31   Performs a delay measured as number of ticks.
     32 
     33   An internal function to perform a delay measured as number of ticks. It's
     34   invoked by MicroSecondDelay() and NanoSecondDelay().
     35 
     36   @param  Delay Number of ticks to delay.
     37 
     38 **/
     39 STATIC
     40 VOID
     41 InternalIpfDelay (
     42   IN      INT64                     Delay
     43   )
     44 {
     45   INT64                             Ticks;
     46 
     47   //
     48   // The target timer count is calculated here
     49   //
     50   Ticks = (INT64)AsmReadItc () + Delay;
     51 
     52   //
     53   // Wait until time out
     54   // Delay > 2^63 could not be handled by this function
     55   // Timer wrap-arounds are handled correctly by this function
     56   //
     57   while (Ticks - (INT64)AsmReadItc() >= 0);
     58 }
     59 
     60 /**
     61   Stalls the CPU for at least the given number of microseconds.
     62 
     63   Stalls the CPU for the number of microseconds specified by MicroSeconds.
     64 
     65   @param  MicroSeconds  The minimum number of microseconds to delay.
     66 
     67   @return MicroSeconds
     68 
     69 **/
     70 UINTN
     71 EFIAPI
     72 MicroSecondDelay (
     73   IN      UINTN                     MicroSeconds
     74   )
     75 {
     76   InternalIpfDelay (
     77     GetPerformanceCounterProperties (NULL, NULL) *
     78     MicroSeconds /
     79     1000000
     80     );
     81   return MicroSeconds;
     82 }
     83 
     84 /**
     85   Stalls the CPU for at least the given number of nanoseconds.
     86 
     87   Stalls the CPU for the number of nanoseconds specified by NanoSeconds.
     88 
     89   @param  NanoSeconds The minimum number of nanoseconds to delay.
     90 
     91   @return NanoSeconds
     92 
     93 **/
     94 UINTN
     95 EFIAPI
     96 NanoSecondDelay (
     97   IN      UINTN                     NanoSeconds
     98   )
     99 {
    100   InternalIpfDelay (
    101     GetPerformanceCounterProperties (NULL, NULL) *
    102     NanoSeconds /
    103     1000000000
    104     );
    105   return NanoSeconds;
    106 }
    107 
    108 /**
    109   Retrieves the current value of a 64-bit free running performance counter.
    110 
    111   Retrieves the current value of a 64-bit free running performance counter. The
    112   counter can either count up by 1 or count down by 1. If the physical
    113   performance counter counts by a larger increment, then the counter values
    114   must be translated. The properties of the counter can be retrieved from
    115   GetPerformanceCounterProperties().
    116 
    117   @return The current value of the free running performance counter.
    118 
    119 **/
    120 UINT64
    121 EFIAPI
    122 GetPerformanceCounter (
    123   VOID
    124   )
    125 {
    126   return AsmReadItc ();
    127 }
    128 
    129 /**
    130   Retrieves the 64-bit frequency in Hz and the range of performance counter
    131   values.
    132 
    133   If StartValue is not NULL, then the value that the performance counter starts
    134   with immediately after is it rolls over is returned in StartValue. If
    135   EndValue is not NULL, then the value that the performance counter end with
    136   immediately before it rolls over is returned in EndValue. The 64-bit
    137   frequency of the performance counter in Hz is always returned. If StartValue
    138   is less than EndValue, then the performance counter counts up. If StartValue
    139   is greater than EndValue, then the performance counter counts down. For
    140   example, a 64-bit free running counter that counts up would have a StartValue
    141   of 0 and an EndValue of 0xFFFFFFFFFFFFFFFF. A 24-bit free running counter
    142   that counts down would have a StartValue of 0xFFFFFF and an EndValue of 0.
    143 
    144   @param  StartValue  The value the performance counter starts with when it
    145                       rolls over.
    146   @param  EndValue    The value that the performance counter ends with before
    147                       it rolls over.
    148 
    149   @return The frequency in Hz.
    150 
    151 **/
    152 UINT64
    153 EFIAPI
    154 GetPerformanceCounterProperties (
    155   OUT      UINT64                    *StartValue,  OPTIONAL
    156   OUT      UINT64                    *EndValue     OPTIONAL
    157   )
    158 {
    159   PAL_CALL_RETURN                   PalRet;
    160   UINT64                            BaseFrequence;
    161 
    162   PalRet = PalCallStatic (NULL, 13, 0, 0, 0);
    163   ASSERT (PalRet.Status == 0);
    164   BaseFrequence = PalRet.r9;
    165 
    166   PalRet = PalCallStatic (NULL, 14, 0, 0, 0);
    167   ASSERT (PalRet.Status == 0);
    168 
    169   if (StartValue != NULL) {
    170     *StartValue = 0;
    171   }
    172 
    173   if (EndValue != NULL) {
    174     *EndValue = (UINT64)(-1);
    175   }
    176 
    177   return BaseFrequence * (PalRet.r11 >> 32) / (UINT32)PalRet.r11;
    178 }
    179