TimestampDxe.c

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#include <Uefi.h>
#include <Library/DebugLib.h>
#include <Library/UefiDriverEntryPoint.h>
#include <Library/UefiBootServicesTableLib.h>
#include <Library/TimerLib.h>
#include <Library/BaseMemoryLib.h>
#include <Protocol/Timestamp.h>
 
//
// The StartValue in TimerLib
//
UINT64  mTimerLibStartValue = 0;
 
//
// The EndValue in TimerLib
//
UINT64  mTimerLibEndValue = 0;
 
//
// The properties of timestamp
//
EFI_TIMESTAMP_PROPERTIES  mTimestampProperties = {
  0,
  0
};
 
UINT64
EFIAPI
TimestampDriverGetTimestamp (
  VOID
  )
{
  //
  // The timestamp of Timestamp Protocol
  //
  UINT64  TimestampValue;
 
  TimestampValue = 0;
 
  //
  // Get the timestamp
  //
  if (mTimerLibStartValue > mTimerLibEndValue) {
    TimestampValue = mTimerLibStartValue - GetPerformanceCounter ();
  } else {
    TimestampValue = GetPerformanceCounter () - mTimerLibStartValue;
  }
 
  return TimestampValue;
}
 
EFI_STATUS
EFIAPI
TimestampDriverGetProperties (
  OUT   EFI_TIMESTAMP_PROPERTIES  *Properties
  )
{
  if (Properties == NULL) {
    return EFI_INVALID_PARAMETER;
  }
 
  //
  // Get timestamp properties
  //
  CopyMem ((VOID *)Properties, (VOID *)&mTimestampProperties, sizeof (mTimestampProperties));
 
  return EFI_SUCCESS;
}
 
//
// The Timestamp Protocol instance produced by this driver
//
EFI_TIMESTAMP_PROTOCOL  mTimestamp = {
  TimestampDriverGetTimestamp,
  TimestampDriverGetProperties
};
 
EFI_STATUS
EFIAPI
TimestampDriverInitialize (
  IN EFI_HANDLE        ImageHandle,
  IN EFI_SYSTEM_TABLE  *SystemTable
  )
{
  EFI_STATUS  Status;
 
  EFI_HANDLE  TimestampHandle;
 
  TimestampHandle = NULL;
 
  //
  // Get the start value, end value and frequency in Timerlib
  //
  mTimestampProperties.Frequency = GetPerformanceCounterProperties (&mTimerLibStartValue, &mTimerLibEndValue);
 
  //
  // Set the EndValue
  //
  if (mTimerLibEndValue > mTimerLibStartValue) {
    mTimestampProperties.EndValue = mTimerLibEndValue - mTimerLibStartValue;
  } else {
    mTimestampProperties.EndValue = mTimerLibStartValue - mTimerLibEndValue;
  }
 
  DEBUG ((DEBUG_INFO, "TimerFrequency:0x%lx, TimerLibStartTime:0x%lx, TimerLibEndtime:0x%lx\n", mTimestampProperties.Frequency, mTimerLibStartValue, mTimerLibEndValue));
 
  //
  // Install the Timestamp Protocol onto a new handle
  //
  Status = gBS->InstallMultipleProtocolInterfaces (
                  &TimestampHandle,
                  &gEfiTimestampProtocolGuid,
                  &mTimestamp,
                  NULL
                  );
 
  ASSERT_EFI_ERROR (Status);
 
  return EFI_SUCCESS;
}