Refine code to make code follow the coding style.

[mirror_edk2.git] / PerformancePkg / Library / TscTimerLib / TscTimerLib.c

/** @file\r
  A Timer Library implementation which uses the Time Stamp Counter in the processor.\r
\r
  For Pentium 4 processors, Intel Xeon processors (family [0FH], models [03H and higher]);\r
    for Intel Core Solo and Intel Core Duo processors (family [06H], model [0EH]);\r
    for the Intel Xeon processor 5100 series and Intel Core 2 Duo processors (family [06H], model [0FH]);\r
    for Intel Core 2 and Intel Xeon processors (family [06H], display_model [17H]);\r
    for Intel Atom processors (family [06H], display_model [1CH]):\r
  the time-stamp counter increments at a constant rate.\r
  That rate may be set by the maximum core-clock to bus-clock ratio of the processor or may be set by\r
  the maximum resolved frequency at which the processor is booted. The maximum resolved frequency may\r
  differ from the maximum qualified frequency of the processor.\r
\r
  The specific processor configuration determines the behavior. Constant TSC behavior ensures that the\r
  duration of each clock tick is uniform and supports the use of the TSC as a wall clock timer even if\r
  the processor core changes frequency.  This is the architectural behavior moving forward.\r
\r
  A Processor's support for invariant TSC is indicated by CPUID.0x80000007.EDX[8].\r
\r
  Copyright (c) 2009 - 2010, Intel Corporation. All rights reserved.<BR>\r
  This program and the accompanying materials\r
  are licensed and made available under the terms and conditions of the BSD License\r
  which accompanies this distribution.  The full text of the license may be found at\r
  http://opensource.org/licenses/bsd-license.php\r
\r
  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r
  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r
\r
**/\r
\r
#include <Base.h>\r
#include <Ich/GenericIch.h>\r
\r
#include <Library/TimerLib.h>\r
#include <Library/BaseLib.h>\r
#include <Library/IoLib.h>\r
#include <Library/PciLib.h>\r
#include <Library/PcdLib.h>\r
\r
STATIC UINT64   mTscFrequency;\r
\r
/** The constructor function determines the actual TSC frequency.\r
\r
  The TSC counting frequency is determined by comparing how far it counts\r
  during a 1ms period as determined by the ACPI timer.  The ACPI timer is\r
  used because it counts at a known frequency.\r
  If ACPI I/O space not enabled, this function will enable it.  Then the\r
  TSC is sampled, followed by waiting for 3579 clocks of the ACPI timer, or 1ms.\r
  The TSC is then sampled again. The difference multiplied by 1000 is the TSC\r
  frequency.  There will be a small error because of the overhead of reading\r
  the ACPI timer.  An attempt is made to determine and compensate for this error.\r
  This function will always return RETURN_SUCCESS.\r
\r
  @retval RETURN_SUCCESS   The constructor always returns RETURN_SUCCESS.\r
\r
**/\r
RETURN_STATUS\r
EFIAPI\r
TscTimerLibConstructor (\r
  VOID\r
  )\r
{\r
  UINT64      StartTSC;\r
  UINT64      EndTSC;\r
  UINT32      TimerAddr;\r
  UINT32      Ticks;\r
\r
  //\r
  // If ACPI I/O space is not enabled yet, program ACPI I/O base address and enable it.\r
  //\r
  if ((PciRead8 (PCI_ICH_LPC_ADDRESS (R_ICH_LPC_ACPI_CNT)) & B_ICH_LPC_ACPI_CNT_ACPI_EN) == 0) {\r
    PciWrite16 (PCI_ICH_LPC_ADDRESS (R_ICH_LPC_ACPI_BASE), PcdGet16 (PcdPerfPkgAcpiIoPortBaseAddress));\r
    PciOr8 (PCI_ICH_LPC_ADDRESS (R_ICH_LPC_ACPI_CNT), B_ICH_LPC_ACPI_CNT_ACPI_EN);\r
  }\r
\r
  TimerAddr = PcdGet16 (PcdPerfPkgAcpiIoPortBaseAddress) + R_ACPI_PM1_TMR;  // Locate the ACPI Timer\r
  Ticks    = IoRead32( TimerAddr) + (3579);   // Set Ticks to 1ms in the future\r
  StartTSC = AsmReadTsc();                    // Get base value for the TSC\r
  //\r
  // Wait until the ACPI timer has counted 1ms.\r
  // Timer wrap-arounds are handled correctly by this function.\r
  // When the current ACPI timer value is greater than 'Ticks', the while loop will exit.\r
  //\r
  while (((Ticks - IoRead32( TimerAddr)) & BIT23) == 0) {\r
    CpuPause();\r
  }\r
  EndTSC = AsmReadTsc();    // TSC value 1ms later\r
\r
  mTscFrequency =   MultU64x32 (\r
                      (EndTSC - StartTSC),    // Number of TSC counts in 1ms\r
                      1000                    // Number of ms in a second\r
                    );\r
  //\r
  // mTscFrequency is now equal to the number of TSC counts per second\r
  //\r
  return RETURN_SUCCESS;\r
}\r
\r
/**  Stalls the CPU for at least the given number of ticks.\r
\r
  Stalls the CPU for at least the given number of ticks. It's invoked by\r
  MicroSecondDelay() and NanoSecondDelay().\r
\r
  @param[in]  Delay     A period of time to delay in ticks.\r
\r
**/\r
VOID\r
InternalX86Delay (\r
  IN      UINT64                    Delay\r
  )\r
{\r
  UINT64                             Ticks;\r
\r
  //\r
  // The target timer count is calculated here\r
  //\r
  Ticks = AsmReadTsc() + Delay;\r
\r
  //\r
  // Wait until time out\r
  // Timer wrap-arounds are NOT handled correctly by this function.\r
  // Thus, this function must be called within 10 years of reset since\r
  // Intel guarantees a minimum of 10 years before the TSC wraps.\r
  //\r
  while (AsmReadTsc() <= Ticks) CpuPause();\r
}\r
\r
/**  Stalls the CPU for at least the specified number of MicroSeconds.\r
\r
  @param[in]  MicroSeconds  The minimum number of microseconds to delay.\r
\r
  @return The value of MicroSeconds input.\r
\r
**/\r
UINTN\r
EFIAPI\r
MicroSecondDelay (\r
  IN      UINTN                     MicroSeconds\r
  )\r
{\r
  InternalX86Delay (\r
    DivU64x32 (\r
      MultU64x64 (\r
        mTscFrequency,\r
        MicroSeconds\r
      ),\r
      1000000u\r
    )\r
  );\r
  return MicroSeconds;\r
}\r
\r
/**  Stalls the CPU for at least the specified number of NanoSeconds.\r
\r
  @param[in]  NanoSeconds The minimum number of nanoseconds to delay.\r
\r
  @return The value of NanoSeconds input.\r
\r
**/\r
UINTN\r
EFIAPI\r
NanoSecondDelay (\r
  IN      UINTN                     NanoSeconds\r
  )\r
{\r
  InternalX86Delay (\r
    DivU64x32 (\r
      MultU64x32 (\r
        mTscFrequency,\r
        (UINT32)NanoSeconds\r
      ),\r
    1000000000u\r
    )\r
  );\r
  return NanoSeconds;\r
}\r
\r
/**  Retrieves the current value of the 64-bit free running Time-Stamp counter.\r
\r
  The time-stamp counter (as implemented in the P6 family, Pentium, Pentium M,\r
  Pentium 4, Intel Xeon, Intel Core Solo and Intel Core Duo processors and\r
  later processors) is a 64-bit counter that is set to 0 following a RESET of\r
  the processor.  Following a RESET, the counter increments even when the\r
  processor is halted by the HLT instruction or the external STPCLK# pin. Note\r
  that the assertion of the external DPSLP# pin may cause the time-stamp\r
  counter to stop.\r
\r
  The properties of the counter can be retrieved by the\r
  GetPerformanceCounterProperties() function.\r
\r
  @return The current value of the free running performance counter.\r
\r
**/\r
UINT64\r
EFIAPI\r
GetPerformanceCounter (\r
  VOID\r
  )\r
{\r
  return AsmReadTsc();\r
}\r
\r
/**  Retrieves the 64-bit frequency in Hz and the range of performance counter\r
  values.\r
\r
  If StartValue is not NULL, then the value that the performance counter starts\r
  with, 0x0, is returned in StartValue. If EndValue is not NULL, then the value\r
  that the performance counter end with, 0xFFFFFFFFFFFFFFFF, is returned in\r
  EndValue.\r
\r
  The 64-bit frequency of the performance counter, in Hz, is always returned.\r
  To determine average processor clock frequency, Intel recommends the use of\r
  EMON logic to count processor core clocks over the period of time for which\r
  the average is required.\r
\r
\r
  @param[out]   StartValue  Pointer to where the performance counter's starting value is saved, or NULL.\r
  @param[out]   EndValue    Pointer to where the performance counter's ending value is saved, or NULL.\r
\r
  @return The frequency in Hz.\r
\r
**/\r
UINT64\r
EFIAPI\r
GetPerformanceCounterProperties (\r
  OUT      UINT64                    *StartValue,  OPTIONAL\r
  OUT      UINT64                    *EndValue     OPTIONAL\r
  )\r
{\r
  if (StartValue != NULL) {\r
    *StartValue = 0;\r
  }\r
  if (EndValue != NULL) {\r
    *EndValue = 0xFFFFFFFFFFFFFFFFull;\r
  }\r
\r
  return mTscFrequency;\r
}\r