DxeTimerLib.c

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#include <PiPei.h>
#include <Library/BaseLib.h>
#include <Library/TimerLib.h>
#include <Library/DebugLib.h>
#include <Library/EmuThunkLib.h>
#include <Library/UefiBootServicesTableLib.h>
#include <Library/UefiLib.h>
 
#include <Protocol/Timer.h>
 
STATIC UINT64                   gTimerPeriod   = 0;
STATIC EFI_TIMER_ARCH_PROTOCOL  *gTimerAp      = NULL;
STATIC EFI_EVENT                gTimerEvent    = NULL;
STATIC VOID                     *gRegistration = NULL;
 
VOID
EFIAPI
RegisterTimerArchProtocol (
  IN EFI_EVENT  Event,
  IN VOID       *Context
  )
{
  EFI_STATUS  Status;
 
  Status = gBS->LocateProtocol (&gEfiTimerArchProtocolGuid, NULL, (VOID **)&gTimerAp);
  if (!EFI_ERROR (Status)) {
    Status = gTimerAp->GetTimerPeriod (gTimerAp, &gTimerPeriod);
    ASSERT_EFI_ERROR (Status);
 
    // Convert to Nanoseconds.
    gTimerPeriod = MultU64x32 (gTimerPeriod, 100);
 
    if (gTimerEvent == NULL) {
      Status = gBS->CreateEvent (EVT_TIMER, 0, NULL, NULL, &gTimerEvent);
      ASSERT_EFI_ERROR (Status);
    }
  }
}
 
UINTN
EFIAPI
MicroSecondDelay (
  IN      UINTN  MicroSeconds
  )
{
  return NanoSecondDelay (MicroSeconds * 1000);
}
 
UINTN
EFIAPI
NanoSecondDelay (
  IN      UINTN  NanoSeconds
  )
{
  EFI_STATUS  Status;
  UINT64      HundredNanoseconds;
  UINTN       Index;
 
  if ((gTimerPeriod != 0) &&
      ((UINT64)NanoSeconds > gTimerPeriod) &&
      (EfiGetCurrentTpl () == TPL_APPLICATION))
  {
    //
    // This stall is long, so use gBS->WaitForEvent () to yield CPU to DXE Core
    //
 
    HundredNanoseconds = DivU64x32 (NanoSeconds, 100);
    Status             = gBS->SetTimer (gTimerEvent, TimerRelative, HundredNanoseconds);
    ASSERT_EFI_ERROR (Status);
 
    Status = gBS->WaitForEvent (sizeof (gTimerEvent)/sizeof (EFI_EVENT), &gTimerEvent, &Index);
    ASSERT_EFI_ERROR (Status);
  } else {
    gEmuThunk->Sleep (NanoSeconds);
  }
 
  return NanoSeconds;
}
 
UINT64
EFIAPI
GetPerformanceCounter (
  VOID
  )
{
  return gEmuThunk->QueryPerformanceCounter ();
}
 
UINT64
EFIAPI
GetPerformanceCounterProperties (
  OUT      UINT64  *StartValue   OPTIONAL,
  OUT      UINT64  *EndValue     OPTIONAL
  )
{
  if (StartValue != NULL) {
    *StartValue = 0ULL;
  }
 
  if (EndValue != NULL) {
    *EndValue = (UINT64)-1LL;
  }
 
  return gEmuThunk->QueryPerformanceFrequency ();
}
 
EFI_STATUS
EFIAPI
DxeTimerLibConstructor (
  IN EFI_HANDLE        ImageHandle,
  IN EFI_SYSTEM_TABLE  *SystemTable
  )
{
  EfiCreateProtocolNotifyEvent (
    &gEfiTimerArchProtocolGuid,
    TPL_CALLBACK,
    RegisterTimerArchProtocol,
    NULL,
    &gRegistration
    );
 
  return EFI_SUCCESS;
}
 
UINT64
EFIAPI
GetTimeInNanoSecond (
  IN UINT64  Ticks
  )
{
  UINT64  Frequency;
  UINT64  NanoSeconds;
  UINT64  Remainder;
  INTN    Shift;
 
  Frequency = GetPerformanceCounterProperties (NULL, NULL);
 
  //
  //          Ticks
  // Time = --------- x 1,000,000,000
  //        Frequency
  //
  NanoSeconds = MultU64x32 (DivU64x64Remainder (Ticks, Frequency, &Remainder), 1000000000u);
 
  //
  // Ensure (Remainder * 1,000,000,000) will not overflow 64-bit.
  // Since 2^29 < 1,000,000,000 = 0x3B9ACA00 < 2^30, Remainder should < 2^(64-30) = 2^34,
  // i.e. highest bit set in Remainder should <= 33.
  //
  Shift        = MAX (0, HighBitSet64 (Remainder) - 33);
  Remainder    = RShiftU64 (Remainder, (UINTN)Shift);
  Frequency    = RShiftU64 (Frequency, (UINTN)Shift);
  NanoSeconds += DivU64x64Remainder (MultU64x32 (Remainder, 1000000000u), Frequency, NULL);
 
  return NanoSeconds;
}