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-rw-r--r--UefiCpuPkg/CpuTimerDxeRiscV64/Timer.c35
1 files changed, 21 insertions, 14 deletions
diff --git a/UefiCpuPkg/CpuTimerDxeRiscV64/Timer.c b/UefiCpuPkg/CpuTimerDxeRiscV64/Timer.c
index db153f715e..287e7e1330 100644
--- a/UefiCpuPkg/CpuTimerDxeRiscV64/Timer.c
+++ b/UefiCpuPkg/CpuTimerDxeRiscV64/Timer.c
@@ -40,7 +40,8 @@ STATIC EFI_TIMER_NOTIFY mTimerNotifyFunction;
//
// The current period of the timer interrupt
//
-STATIC UINT64 mTimerPeriod = 0;
+STATIC UINT64 mTimerPeriod = 0;
+STATIC UINT64 mLastPeriodStart = 0;
/**
Timer Interrupt Handler.
@@ -56,25 +57,33 @@ TimerInterruptHandler (
)
{
EFI_TPL OriginalTPL;
- UINT64 RiscvTimer;
+ UINT64 PeriodStart;
+
+ PeriodStart = RiscVReadTimer ();
OriginalTPL = gBS->RaiseTPL (TPL_HIGH_LEVEL);
if (mTimerNotifyFunction != NULL) {
- mTimerNotifyFunction (mTimerPeriod);
+ //
+ // For any number of reasons, the ticks could be coming
+ // in slower than mTimerPeriod. For example, some code
+ // is doing a *lot* of stuff inside an EFI_TPL_HIGH
+ // critical section, and this should not cause the EFI
+ // time to increment slower. So when we take an interrupt,
+ // account for the actual time passed.
+ //
+ mTimerNotifyFunction (PeriodStart - mLastPeriodStart);
}
- RiscVDisableTimerInterrupt (); // Disable SMode timer int
- RiscVClearPendingTimerInterrupt ();
if (mTimerPeriod == 0) {
+ RiscVDisableTimerInterrupt ();
gBS->RestoreTPL (OriginalTPL);
- RiscVDisableTimerInterrupt (); // Disable SMode timer int
return;
}
- RiscvTimer = RiscVReadTimer ();
- SbiSetTimer (RiscvTimer += mTimerPeriod);
- gBS->RestoreTPL (OriginalTPL);
+ mLastPeriodStart = PeriodStart;
+ SbiSetTimer (PeriodStart += mTimerPeriod);
RiscVEnableTimerInterrupt (); // enable SMode timer int
+ gBS->RestoreTPL (OriginalTPL);
}
/**
@@ -154,8 +163,6 @@ TimerDriverSetTimerPeriod (
IN UINT64 TimerPeriod
)
{
- UINT64 RiscvTimer;
-
DEBUG ((DEBUG_INFO, "TimerDriverSetTimerPeriod(0x%lx)\n", TimerPeriod));
if (TimerPeriod == 0) {
@@ -164,9 +171,9 @@ TimerDriverSetTimerPeriod (
return EFI_SUCCESS;
}
- mTimerPeriod = TimerPeriod / 10; // convert unit from 100ns to 1us
- RiscvTimer = RiscVReadTimer ();
- SbiSetTimer (RiscvTimer + mTimerPeriod);
+ mTimerPeriod = TimerPeriod / 10; // convert unit from 100ns to 1us
+ mLastPeriodStart = RiscVReadTimer ();
+ SbiSetTimer (mLastPeriodStart + mTimerPeriod);
mCpu->EnableInterrupt (mCpu);
RiscVEnableTimerInterrupt (); // enable SMode timer int