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- /** @file
- RISC-V instance of Timer Library.
- Copyright (c) 2016 - 2022, Hewlett Packard Enterprise Development LP. All rights reserved.<BR>
- SPDX-License-Identifier: BSD-2-Clause-Patent
- **/
- #include <Uefi.h>
- #include <Library/BaseLib.h>
- #include <Library/DebugLib.h>
- #include <Library/PcdLib.h>
- #include <Register/RiscV64/RiscVImpl.h>
- /**
- Stalls the CPU for at least the given number of ticks.
- Stalls the CPU for at least the given number of ticks. It's invoked by
- MicroSecondDelay() and NanoSecondDelay().
- @param Delay A period of time to delay in ticks.
- **/
- VOID
- InternalRiscVTimerDelay (
- IN UINT32 Delay
- )
- {
- UINT32 Ticks;
- UINT32 Times;
- Times = Delay >> (RISCV_TIMER_COMPARE_BITS - 2);
- Delay &= ((1 << (RISCV_TIMER_COMPARE_BITS - 2)) - 1);
- do {
- //
- // The target timer count is calculated here
- //
- Ticks = RiscVReadTimer () + Delay;
- Delay = 1 << (RISCV_TIMER_COMPARE_BITS - 2);
- while (((Ticks - RiscVReadTimer ()) & (1 << (RISCV_TIMER_COMPARE_BITS - 1))) == 0) {
- CpuPause ();
- }
- } while (Times-- > 0);
- }
- /**
- 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
- )
- {
- InternalRiscVTimerDelay (
- (UINT32)DivU64x32 (
- MultU64x32 (
- MicroSeconds,
- PcdGet64 (PcdCpuCoreCrystalClockFrequency)
- ),
- 1000000u
- )
- );
- 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
- )
- {
- InternalRiscVTimerDelay (
- (UINT32)DivU64x32 (
- MultU64x32 (
- NanoSeconds,
- PcdGet64 (PcdCpuCoreCrystalClockFrequency)
- ),
- 1000000000u
- )
- );
- 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 (UINT64)RiscVReadTimer ();
- }
- /**return
- 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 = 0;
- }
- if (EndValue != NULL) {
- *EndValue = 32 - 1;
- }
- return PcdGet64 (PcdCpuCoreCrystalClockFrequency);
- }
- /**
- 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 NanoSeconds;
- UINT32 Remainder;
- //
- // Ticks
- // Time = --------- x 1,000,000,000
- // Frequency
- //
- NanoSeconds = MultU64x32 (DivU64x32Remainder (Ticks, PcdGet64 (PcdCpuCoreCrystalClockFrequency), &Remainder), 1000000000u);
- //
- // Frequency < 0x100000000, so Remainder < 0x100000000, then (Remainder * 1,000,000,000)
- // will not overflow 64-bit.
- //
- NanoSeconds += DivU64x32 (MultU64x32 ((UINT64)Remainder, 1000000000u), PcdGet64 (PcdCpuCoreCrystalClockFrequency));
- return NanoSeconds;
- }
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