MdePkg/Library/SecPeiDxeTimerLibCpu/X86TimerLib.c

   1 /** @file
   2   Timer Library functions built upon local APIC on IA32/x64.
   3
   4   Copyright (c) 2006 - 2013, Intel Corporation. All rights reserved.<BR>
   5   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/PcdLib.h>
  20 #include <Library/DebugLib.h>
  21
  22 #define APIC_LVTERR     0x370
  23 #define APIC_TMICT      0x380
  24 #define APIC_TMCCT      0x390
  25 #define APIC_TDCR       0x3e0
  26
  27 //
  28 // The following array is used in calculating the frequency of local APIC
  29 // timer. Refer to IA-32 developers' manual for more details.
  30 //
  31 GLOBAL_REMOVE_IF_UNREFERENCED
  32 CONST UINT8                           mTimerLibLocalApicDivisor[] = {
  33   0x02, 0x04, 0x08, 0x10,
  34   0x02, 0x04, 0x08, 0x10,
  35   0x20, 0x40, 0x80, 0x01,
  36   0x20, 0x40, 0x80, 0x01
  37 };
  38
  39 /**
  40   Internal function to retrieve the base address of local APIC.
  41
  42   @return The base address of local APIC
  43
  44 **/
  45 UINTN
  46 EFIAPI
  47 InternalX86GetApicBase (
  48   VOID
  49   )
  50 {
  51   return (UINTN)AsmMsrBitFieldRead64 (27, 12, 35) << 12;
  52 }
  53
  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 UINT32
  63 EFIAPI
  64 InternalX86GetTimerFrequency (
  65   IN      UINTN                     ApicBase
  66   )
  67 {
  68   return
  69     PcdGet32(PcdFSBClock) /
  70     mTimerLibLocalApicDivisor[MmioBitFieldRead32 (ApicBase + APIC_TDCR, 0, 3)];
  71 }
  72
  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 EFIAPI
  83 InternalX86GetTimerTick (
  84   IN      UINTN                     ApicBase
  85   )
  86 {
  87   return MmioRead32 (ApicBase + APIC_TMCCT);
  88 }
  89
  90 /**
  91   Internal function to read the initial timer count of local APIC.
  92
  93   @param  ApicBase  The base address of memory mapped registers of local APIC.
  94
  95   @return The initial timer count read.
  96
  97 **/
  98 UINT32
  99 InternalX86GetInitTimerCount (
 100   IN      UINTN                     ApicBase
 101   )
 102 {
 103   return MmioRead32 (ApicBase + APIC_TMICT);
 104 }
 105
 106 /**
 107   Stalls the CPU for at least the given number of ticks.
 108
 109   Stalls the CPU for at least the given number of ticks. It's invoked by
 110   MicroSecondDelay() and NanoSecondDelay().
 111
 112   @param  ApicBase  The base address of memory mapped registers of local APIC.
 113   @param  Delay     A period of time to delay in ticks.
 114
 115 **/
 116 VOID
 117 EFIAPI
 118 InternalX86Delay (
 119   IN      UINTN                     ApicBase,
 120   IN      UINT32                    Delay
 121   )
 122 {
 123   INT32                             Ticks;
 124   UINT32                            Times;
 125   UINT32                            InitCount;
 126   UINT32                            StartTick;
 127
 128   //
 129   // In case Delay is too larger, separate it into several small delay slot.
 130   // Devided Delay by half value of Init Count is to avoid Delay close to
 131   // the Init Count, timeout maybe missing if the time consuming between 2
 132   // GetApicTimerCurrentCount() invoking is larger than the time gap between
 133   // Delay and the Init Count.
 134   //
 135   InitCount = InternalX86GetInitTimerCount (ApicBase);
 136   Times     = Delay / (InitCount / 2);
 137   Delay     = Delay % (InitCount / 2);
 138
 139   //
 140   // Get Start Tick and do delay
 141   //
 142   StartTick  = InternalX86GetTimerTick (ApicBase);
 143   do {
 144     //
 145     // Wait until time out by Delay value
 146     //
 147     do {
 148       CpuPause ();
 149       //
 150       // Get Ticks from Start to Current.
 151       //
 152       Ticks = StartTick - InternalX86GetTimerTick (ApicBase);
 153       //
 154       // Ticks < 0 means Timer wrap-arounds happens.
 155       //
 156       if (Ticks < 0) {
 157         Ticks += InitCount;
 158       }
 159     } while ((UINT32)Ticks < Delay);
 160
 161     //
 162     // Update StartTick and Delay for next delay slot
 163     //
 164     StartTick -= (StartTick > Delay) ?  Delay : (Delay - InitCount);
 165     Delay      = InitCount / 2;
 166   } while (Times-- > 0);
 167 }
 168
 169 /**
 170   Stalls the CPU for at least the given number of microseconds.
 171
 172   Stalls the CPU for the number of microseconds specified by MicroSeconds.
 173
 174   @param  MicroSeconds  The minimum number of microseconds to delay.
 175
 176   @return The value of MicroSeconds inputted.
 177
 178 **/
 179 UINTN
 180 EFIAPI
 181 MicroSecondDelay (
 182   IN      UINTN                     MicroSeconds
 183   )
 184 {
 185   UINTN                             ApicBase;
 186
 187   ApicBase = InternalX86GetApicBase ();
 188   InternalX86Delay (
 189     ApicBase,
 190     (UINT32)DivU64x32 (
 191               MultU64x64 (
 192                 InternalX86GetTimerFrequency (ApicBase),
 193                 MicroSeconds
 194                 ),
 195               1000000u
 196               )
 197     );
 198   return MicroSeconds;
 199 }
 200
 201 /**
 202   Stalls the CPU for at least the given number of nanoseconds.
 203
 204   Stalls the CPU for the number of nanoseconds specified by NanoSeconds.
 205
 206   @param  NanoSeconds The minimum number of nanoseconds to delay.
 207
 208   @return The value of NanoSeconds inputted.
 209
 210 **/
 211 UINTN
 212 EFIAPI
 213 NanoSecondDelay (
 214   IN      UINTN                     NanoSeconds
 215   )
 216 {
 217   UINTN                             ApicBase;
 218
 219   ApicBase = InternalX86GetApicBase ();
 220   InternalX86Delay (
 221     ApicBase,
 222     (UINT32)DivU64x32 (
 223               MultU64x64 (
 224                 InternalX86GetTimerFrequency (ApicBase),
 225                 NanoSeconds
 226                 ),
 227               1000000000u
 228               )
 229     );
 230   return NanoSeconds;
 231 }
 232
 233 /**
 234   Retrieves the current value of a 64-bit free running performance counter.
 235
 236   The counter can either count up by 1 or count down by 1. If the physical
 237   performance counter counts by a larger increment, then the counter values
 238   must be translated. The properties of the counter can be retrieved from
 239   GetPerformanceCounterProperties().
 240
 241   @return The current value of the free running performance counter.
 242
 243 **/
 244 UINT64
 245 EFIAPI
 246 GetPerformanceCounter (
 247   VOID
 248   )
 249 {
 250   return (UINT64)(UINT32)InternalX86GetTimerTick (InternalX86GetApicBase ());
 251 }
 252
 253 /**
 254   Retrieves the 64-bit frequency in Hz and the range of performance counter
 255   values.
 256
 257   If StartValue is not NULL, then the value that the performance counter starts
 258   with immediately after is it rolls over is returned in StartValue. If
 259   EndValue is not NULL, then the value that the performance counter end with
 260   immediately before it rolls over is returned in EndValue. The 64-bit
 261   frequency of the performance counter in Hz is always returned. If StartValue
 262   is less than EndValue, then the performance counter counts up. If StartValue
 263   is greater than EndValue, then the performance counter counts down. For
 264   example, a 64-bit free running counter that counts up would have a StartValue
 265   of 0 and an EndValue of 0xFFFFFFFFFFFFFFFF. A 24-bit free running counter
 266   that counts down would have a StartValue of 0xFFFFFF and an EndValue of 0.
 267
 268   @param  StartValue  The value the performance counter starts with when it
 269                       rolls over.
 270   @param  EndValue    The value that the performance counter ends with before
 271                       it rolls over.
 272
 273   @return The frequency in Hz.
 274
 275 **/
 276 UINT64
 277 EFIAPI
 278 GetPerformanceCounterProperties (
 279   OUT      UINT64                    *StartValue,  OPTIONAL
 280   OUT      UINT64                    *EndValue     OPTIONAL
 281   )
 282 {
 283   UINTN                             ApicBase;
 284
 285   ApicBase = InternalX86GetApicBase ();
 286
 287   if (StartValue != NULL) {
 288     *StartValue = (UINT64)InternalX86GetInitTimerCount (ApicBase);
 289   }
 290
 291   if (EndValue != NULL) {
 292     *EndValue = 0;
 293   }
 294
 295   return (UINT64) InternalX86GetTimerFrequency (ApicBase);
 296 }
 297
 298 /**
 299   Converts elapsed ticks of performance counter to time in nanoseconds.
 300
 301   This function converts the elapsed ticks of running performance counter to
 302   time value in unit of nanoseconds.
 303
 304   @param  Ticks     The number of elapsed ticks of running performance counter.
 305
 306   @return The elapsed time in nanoseconds.
 307
 308 **/
 309 UINT64
 310 EFIAPI
 311 GetTimeInNanoSecond (
 312   IN      UINT64                     Ticks
 313   )
 314 {
 315   UINT64  Frequency;
 316   UINT64  NanoSeconds;
 317   UINT64  Remainder;
 318   INTN    Shift;
 319
 320   Frequency = GetPerformanceCounterProperties (NULL, NULL);
 321
 322   //
 323   //          Ticks
 324   // Time = --------- x 1,000,000,000
 325   //        Frequency
 326   //
 327   NanoSeconds = MultU64x32 (DivU64x64Remainder (Ticks, Frequency, &Remainder), 1000000000u);
 328
 329   //
 330   // Ensure (Remainder * 1,000,000,000) will not overflow 64-bit.
 331   // Since 2^29 < 1,000,000,000 = 0x3B9ACA00 < 2^30, Remainder should < 2^(64-30) = 2^34,
 332   // i.e. highest bit set in Remainder should <= 33.
 333   //
 334   Shift = MAX (0, HighBitSet64 (Remainder) - 33);
 335   Remainder = RShiftU64 (Remainder, (UINTN) Shift);
 336   Frequency = RShiftU64 (Frequency, (UINTN) Shift);
 337   NanoSeconds += DivU64x64Remainder (MultU64x32 (Remainder, 1000000000u), Frequency, NULL);
 338
 339   return NanoSeconds;
 340 }