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- /** @file
- Generic LoongArch implementation of TimerLib.h
- Copyright (c) 2022 Loongson Technology Corporation Limited. All rights reserved.<BR>
- SPDX-License-Identifier: BSD-2-Clause-Patent
- @par Glossary:
- - Freq - Frequency
- - Csr - Cpu Status Register
- - calc - calculate
- **/
- #include <Base.h>
- #include <Library/TimerLib.h>
- #include <Library/BaseLib.h>
- #include <Library/DebugLib.h>
- #include "Library/StableTimer.h"
- #include "Library/Cpu.h"
- UINT32 StableTimerFreq = 0;
- /**
- Calculate the timer frequency.
- @param[] VOID
- @retval Timer frequency.
- **/
- UINT32
- EFIAPI
- CalcConstFreq (
- VOID
- )
- {
- UINT32 Result;
- UINT32 BaseFreq;
- UINT32 ClockMultiplier;
- UINT32 ClockDivide;
- UINT64 Val;
- LoongArchReadCpuCfg (&Val, LOONGARCH_CPUCFG4);
- BaseFreq = (UINT32)Val;
- LoongArchReadCpuCfg (&Val, LOONGARCH_CPUCFG5);
- Result = (UINT32)Val;
- ClockMultiplier = Result & 0xffff;
- ClockDivide = (Result >> 16) & 0xffff;
- if ((!BaseFreq) || (!ClockMultiplier) || (!ClockDivide)) {
- return 0;
- } else {
- return (BaseFreq * ClockMultiplier / ClockDivide);
- }
- }
- /**
- Get the timer frequency.
- @param[] VOID
- @retval Timer frequency.
- **/
- UINT32
- EFIAPI
- GetFreq (
- VOID
- )
- {
- if (StableTimerFreq) {
- } else {
- StableTimerFreq = CalcConstFreq ();
- }
- return StableTimerFreq;
- }
- /**
- Stalls the CPU for at least the given number of microseconds.
- Stalls the CPU for the number of microseconds specified by MicroSeconds.
- @param MicroSeconds The minimum number of microseconds to delay.
- @return MicroSeconds
- **/
- UINTN
- EFIAPI
- MicroSecondDelay (
- IN UINTN MicroSeconds
- )
- {
- UINTN Count;
- UINTN Ticks;
- UINTN Start;
- UINTN End;
- Count = GetFreq ();
- Count = (Count * MicroSeconds) / 1000000;
- Start = LoongArchReadTime ();
- End = Start + Count;
- do {
- Ticks = LoongArchReadTime ();
- } while (Ticks < End);
- return MicroSeconds;
- }
- /**
- Stalls the CPU for at least the given number of nanoseconds.
- Stalls the CPU for the number of nanoseconds specified by NanoSeconds.
- @param NanoSeconds The minimum number of nanoseconds to delay.
- @return NanoSeconds
- **/
- UINTN
- EFIAPI
- NanoSecondDelay (
- IN UINTN NanoSeconds
- )
- {
- UINT32 MicroSeconds;
- if (NanoSeconds % 1000 == 0) {
- MicroSeconds = NanoSeconds/1000;
- } else {
- MicroSeconds = NanoSeconds/1000 + 1;
- }
- MicroSecondDelay (MicroSeconds);
- return NanoSeconds;
- }
- /**
- Retrieves the current value of a 64-bit free running performance counter.
- Retrieves the current value of a 64-bit free running performance counter. The
- counter can either count up by 1 or count down by 1. If the physical
- performance counter counts by a larger increment, then the counter values
- must be translated. The properties of the counter can be retrieved from
- GetPerformanceCounterProperties ().
- @return The current value of the free running performance counter.
- **/
- UINT64
- EFIAPI
- GetPerformanceCounter (
- VOID
- )
- {
- return LoongArchReadTime ();
- }
- /**
- Retrieves the 64-bit frequency in Hz and the range of performance counter
- values.
- If StartValue is not NULL, then the value that the performance counter starts
- with immediately after is it rolls over is returned in StartValue. If
- EndValue is not NULL, then the value that the performance counter end with
- immediately before it rolls over is returned in EndValue. The 64-bit
- frequency of the performance counter in Hz is always returned. If StartValue
- is less than EndValue, then the performance counter counts up. If StartValue
- is greater than EndValue, then the performance counter counts down. For
- example, a 64-bit free running counter that counts up would have a StartValue
- of 0 and an EndValue of 0xFFFFFFFFFFFFFFFF. A 24-bit free running counter
- that counts down would have a StartValue of 0xFFFFFF and an EndValue of 0.
- @param StartValue The value the performance counter starts with when it
- rolls over.
- @param EndValue The value that the performance counter ends with before
- it rolls over.
- @return The frequency in Hz.
- **/
- UINT64
- EFIAPI
- GetPerformanceCounterProperties (
- OUT UINT64 *StartValue, OPTIONAL
- OUT UINT64 *EndValue OPTIONAL
- )
- {
- if (StartValue != NULL) {
- *StartValue = BIT2;
- }
- if (EndValue != NULL) {
- *EndValue = BIT48 - 1;
- }
- return GetFreq ();
- }
- /**
- Converts elapsed ticks of performance counter to time in nanoseconds.
- This function converts the elapsed ticks of running performance counter to
- time value in unit of nanoseconds.
- @param Ticks The number of elapsed ticks of running performance counter.
- @return The elapsed time in nanoseconds.
- **/
- 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;
- }
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