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/** @file
SMM Timer feature support
Copyright (c) 2009 - 2015, Intel Corporation. All rights reserved.<BR>
This program and the accompanying materials
are licensed and made available under the terms and conditions of the BSD License
which accompanies this distribution. The full text of the license may be found at
http://opensource.org/licenses/bsd-license.php
THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
**/
#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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