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/** @file
SMM Timer feature support
Copyright (c) 2009 - 2015, Intel Corporation. All rights reserved.<BR>
SPDX-License-Identifier: BSD-2-Clause-Patent
**/
#include "PiSmmCpuDxeSmm.h"
UINT64 mTimeoutTicker = 0;
//
// Number of counts in a roll-over cycle of the performance counter.
//
UINT64 mCycle = 0;
//
// Flag to indicate the performance counter is count-up or count-down.
//
BOOLEAN mCountDown;
/**
Initialize Timer for SMM AP Sync.
**/
VOID
InitializeSmmTimer (
VOID
)
{
UINT64 TimerFrequency;
UINT64 Start;
UINT64 End;
TimerFrequency = GetPerformanceCounterProperties (&Start, &End);
mTimeoutTicker = DivU64x32 (
MultU64x64 (TimerFrequency, PcdGet64 (PcdCpuSmmApSyncTimeout)),
1000 * 1000
);
if (End < Start) {
mCountDown = TRUE;
mCycle = Start - End;
} else {
mCountDown = FALSE;
mCycle = End - Start;
}
}
/**
Start Timer for SMM AP Sync.
**/
UINT64
EFIAPI
StartSyncTimer (
VOID
)
{
return GetPerformanceCounter ();
}
/**
Check if the SMM AP Sync timer is timeout.
@param Timer The start timer from the begin.
**/
BOOLEAN
EFIAPI
IsSyncTimerTimeout (
IN UINT64 Timer
)
{
UINT64 CurrentTimer;
UINT64 Delta;
CurrentTimer = GetPerformanceCounter ();
//
// We need to consider the case that CurrentTimer is equal to Timer
// when some timer runs too slow and CPU runs fast. We think roll over
// condition does not happen on this case.
//
if (mCountDown) {
//
// The performance counter counts down. Check for roll over condition.
//
if (CurrentTimer <= Timer) {
Delta = Timer - CurrentTimer;
} else {
//
// Handle one roll-over.
//
Delta = mCycle - (CurrentTimer - Timer) + 1;
}
} else {
//
// The performance counter counts up. Check for roll over condition.
//
if (CurrentTimer >= Timer) {
Delta = CurrentTimer - Timer;
} else {
//
// Handle one roll-over.
//
Delta = mCycle - (Timer - CurrentTimer) + 1;
}
}
return (BOOLEAN)(Delta >= mTimeoutTicker);
}
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