ArmRealViewEbPkg/Library/TimerLib/TimerLib.c

   1 /** @file
   2   TimerLib for ARM EB. Hardcoded to 100ns period
   3
   4   This library assume the following initialization, usually done in SEC.
   5
   6   // configure SP810 to use 1MHz clock and disable
   7   MmioAndThenOr32 (EB_SP810_CTRL_BASE + SP810_SYS_CTRL_REG, ~SP810_SYS_CTRL_TIMER2_EN, SP810_SYS_CTRL_TIMER2_TIMCLK);
   8   // Enable
   9   MmioOr32 (EB_SP810_CTRL_BASE + SP810_SYS_CTRL_REG, SP810_SYS_CTRL_TIMER2_EN);
  10
  11   // configure timer 2 for one shot operation, 32 bits, no prescaler, and interrupt disabled
  12   MmioOr32 (EB_SP804_TIMER2_BASE + SP804_TIMER_CONTROL_REG, SP804_TIMER_CTRL_ONESHOT | SP804_TIMER_CTRL_32BIT | SP804_PRESCALE_DIV_1);
  13
  14   // preload the timer count register
  15   MmioWrite32 (EB_SP804_TIMER2_BASE + SP804_TIMER_LOAD_REG, 1);
  16
  17   // enable the timer
  18   MmioOr32 (EB_SP804_TIMER2_BASE + SP804_TIMER_CONTROL_REG, SP804_TIMER_CTRL_ENABLE);
  19
  20
  21   Copyright (c) 2008 - 2010, Apple Inc. All rights reserved.<BR>
  22
  23   This program and the accompanying materials
  24   are licensed and made available under the terms and conditions of the BSD License
  25   which accompanies this distribution.  The full text of the license may be found at
  26   http://opensource.org/licenses/bsd-license.php
  27
  28   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  29   WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  30
  31 **/
  32
  33 #include <Base.h>
  34
  35 #include <Library/BaseLib.h>
  36 #include <Library/TimerLib.h>
  37 #include <Library/DebugLib.h>
  38 #include <Library/PcdLib.h>
  39 #include <Library/IoLib.h>
  40
  41 #include <ArmEb/ArmEb.h>
  42
  43
  44 /**
  45   Stalls the CPU for at least the given number of microseconds.
  46
  47   Stalls the CPU for the number of microseconds specified by MicroSeconds.
  48
  49   @param  MicroSeconds  The minimum number of microseconds to delay.
  50
  51   @return The value of MicroSeconds inputted.
  52
  53 **/
  54 UINTN
  55 EFIAPI
  56 MicroSecondDelay (
  57   IN  UINTN MicroSeconds
  58   )
  59 {
  60   UINT64  NanoSeconds;
  61
  62   NanoSeconds = MultU64x32 (MicroSeconds, 1000);
  63
  64   while (NanoSeconds > (UINTN)-1) {
  65     NanoSecondDelay((UINTN)-1);
  66     NanoSeconds -= (UINTN)-1;
  67   }
  68
  69   NanoSecondDelay (NanoSeconds);
  70
  71   return MicroSeconds;
  72 }
  73
  74 /**
  75   Stalls the CPU for at least the given number of nanoseconds.
  76
  77   Stalls the CPU for the number of nanoseconds specified by NanoSeconds.
  78
  79   @param  NanoSeconds The minimum number of nanoseconds to delay.
  80
  81   @return The value of NanoSeconds inputted.
  82
  83 **/
  84 UINTN
  85 EFIAPI
  86 NanoSecondDelay (
  87   IN  UINTN NanoSeconds
  88   )
  89 {
  90   UINT32  TickNumber;
  91
  92   if (NanoSeconds == 0) {
  93     return NanoSeconds;
  94   }
  95
  96   // Round up to 100ns Tick Number
  97   TickNumber =   (UINT32)NanoSeconds / 100;
  98   TickNumber += ((UINT32)NanoSeconds % 100) == 0 ? 0 : 1;
  99
 100   // load the timer count register
 101   MmioWrite32 (EB_SP804_TIMER2_BASE + SP804_TIMER_LOAD_REG, TickNumber);
 102
 103   while (MmioRead32 (EB_SP804_TIMER2_BASE + SP804_TIMER_CURRENT_REG) > 0) {
 104     ;
 105   }
 106
 107   return NanoSeconds;
 108 }
 109
 110 /**
 111   Retrieves the current value of a 64-bit free running performance counter.
 112
 113   The counter can either count up by 1 or count down by 1. If the physical
 114   performance counter counts by a larger increment, then the counter values
 115   must be translated. The properties of the counter can be retrieved from
 116   GetPerformanceCounterProperties().
 117
 118   @return The current value of the free running performance counter.
 119
 120 **/
 121 UINT64
 122 EFIAPI
 123 GetPerformanceCounter (
 124   VOID
 125   )
 126 {
 127   // Free running 64-bit/32-bit counter is needed here.
 128   // Don't think we need this to boot, just to do performance profile
 129   ASSERT (FALSE);
 130   return (UINT64)0ULL;
 131 }
 132
 133
 134 /**
 135   Retrieves the 64-bit frequency in Hz and the range of performance counter
 136   values.
 137
 138   If StartValue is not NULL, then the value that the performance counter starts
 139   with immediately after is it rolls over is returned in StartValue. If
 140   EndValue is not NULL, then the value that the performance counter end with
 141   immediately before it rolls over is returned in EndValue. The 64-bit
 142   frequency of the performance counter in Hz is always returned. If StartValue
 143   is less than EndValue, then the performance counter counts up. If StartValue
 144   is greater than EndValue, then the performance counter counts down. For
 145   example, a 64-bit free running counter that counts up would have a StartValue
 146   of 0 and an EndValue of 0xFFFFFFFFFFFFFFFF. A 24-bit free running counter
 147   that counts down would have a StartValue of 0xFFFFFF and an EndValue of 0.
 148
 149   @param  StartValue  The value the performance counter starts with when it
 150                       rolls over.
 151   @param  EndValue    The value that the performance counter ends with before
 152                       it rolls over.
 153
 154   @return The frequency in Hz.
 155
 156 **/
 157 UINT64
 158 EFIAPI
 159 GetPerformanceCounterProperties (
 160   OUT UINT64  *StartValue,  OPTIONAL
 161   OUT UINT64  *EndValue     OPTIONAL
 162   )
 163 {
 164   if (StartValue != NULL) {
 165     // Timer starts with the reload value
 166     *StartValue = (UINT64)0ULL;
 167   }
 168
 169   if (EndValue != NULL) {
 170     // Timer counts up to 0xFFFFFFFF
 171     *EndValue = 0xFFFFFFFF;
 172   }
 173
 174   return 100;
 175 }
 176
 177