Re: [edk2-devel] [edk2-platforms][PATCH V1 06/16] Platform/Loongson: Add StableTimerLib.

["Michael D Kinney" <michael.d.kinney@intel.com>]

I see a mix of inline assembly and .S files.  Recommend avoiding inline assembly.

Also appears to be some TAB characters in this patch.  Convert tabs to spaces.

Mike

> -----Original Message-----
> From: devel@edk2.groups.io <devel@edk2.groups.io> On Behalf Of xianglai
> Sent: Thursday, September 8, 2022 8:12 PM
> To: devel@edk2.groups.io
> Cc: maobibo@loongson.cn
> Subject: [edk2-devel] [edk2-platforms][PATCH V1 06/16] Platform/Loongson: Add StableTimerLib.
> 
> This library provides a delay interface and a timing interface.
> 
> Signed-off-by: xianglai li <lixianglai@loongson.cn>
> ---
>  .../Include/Library/StableTimer.h             |  42 +++
>  .../Library/StableTimerLib/Count.S            |  26 ++
>  .../Library/StableTimerLib/TimerLib.c         | 262 ++++++++++++++++++
>  .../Library/StableTimerLib/TimerLib.inf       |  28 ++
>  4 files changed, 358 insertions(+)
>  create mode 100644 Platform/Loongson/LoongArchQemuPkg/Include/Library/StableTimer.h
>  create mode 100644 Platform/Loongson/LoongArchQemuPkg/Library/StableTimerLib/Count.S
>  create mode 100644 Platform/Loongson/LoongArchQemuPkg/Library/StableTimerLib/TimerLib.c
>  create mode 100644 Platform/Loongson/LoongArchQemuPkg/Library/StableTimerLib/TimerLib.inf
> 
> diff --git a/Platform/Loongson/LoongArchQemuPkg/Include/Library/StableTimer.h
> b/Platform/Loongson/LoongArchQemuPkg/Include/Library/StableTimer.h
> new file mode 100644
> index 0000000000..bd6a1eb90f
> --- /dev/null
> +++ b/Platform/Loongson/LoongArchQemuPkg/Include/Library/StableTimer.h
> @@ -0,0 +1,42 @@
> +/** @file
> 
> +
> 
> +  Copyright (c) 2021 Loongson Technology Corporation Limited. All rights reserved.<BR>
> 
> +
> 
> +  SPDX-License-Identifier: BSD-2-Clause-Patent
> 
> +
> 
> +  @par Glossary:
> 
> +    - Csr    - Cpu Status Register
> 
> +    - Calc   - Calculation
> 
> +    - Freq   - frequency
> 
> +**/
> 
> +
> 
> +#ifndef STABLE_TIMER_H_
> 
> +#define STABLE_TIMER_H_
> 
> +#include "Library/Cpu.h"
> 
> +
> 
> +/**
> 
> +  Gets the timer count value.
> 
> +
> 
> +  @param[] VOID
> 
> +
> 
> +  @retval  timer count value.
> 
> +**/
> 
> +UINTN
> 
> +EFIAPI
> 
> +CsrReadTime (
> 
> +  VOID
> 
> +  );
> 
> +
> 
> +/**
> 
> +  Calculate the timer frequency.
> 
> +
> 
> +  @param[] VOID
> 
> +
> 
> +  @retval  Timer frequency.
> 
> +**/
> 
> +UINT32
> 
> +EFIAPI
> 
> +CalcConstFreq (
> 
> +  VOID
> 
> +  );
> 
> +#endif
> 
> diff --git a/Platform/Loongson/LoongArchQemuPkg/Library/StableTimerLib/Count.S
> b/Platform/Loongson/LoongArchQemuPkg/Library/StableTimerLib/Count.S
> new file mode 100644
> index 0000000000..42f878caf8
> --- /dev/null
> +++ b/Platform/Loongson/LoongArchQemuPkg/Library/StableTimerLib/Count.S
> @@ -0,0 +1,26 @@
> +#------------------------------------------------------------------------------
> 
> +#
> 
> +# Count for LoongArch
> 
> +#
> 
> +# Copyright (c) 2021 Loongson Technology Corporation Limited. All rights reserved.<BR>
> 
> +#
> 
> +# SPDX-License-Identifier: BSD-2-Clause-Patent
> 
> +#
> 
> +#------------------------------------------------------------------------------
> 
> +
> 
> +#ifndef __ASSEMBLY__
> 
> +#define  __ASSEMBLY__
> 
> +#endif
> 
> +
> 
> +#include "Library/Cpu.h"
> 
> +#include "LoongArchAsmMacro.h"
> 
> +#
> 
> +# Set cpu interrupts
> 
> +# @param A0 The interrupt number
> 
> +#
> 
> +ASM_FUNC(CpuSetIP)
> 
> +    csrrd   T0, LOONGARCH_CSR_ECFG
> 
> +    or      T0, T0, A0
> 
> +    csrwr   T0, LOONGARCH_CSR_ECFG
> 
> +    jirl    ZERO, RA,0
> 
> +
> 
> diff --git a/Platform/Loongson/LoongArchQemuPkg/Library/StableTimerLib/TimerLib.c
> b/Platform/Loongson/LoongArchQemuPkg/Library/StableTimerLib/TimerLib.c
> new file mode 100644
> index 0000000000..21e3749ee6
> --- /dev/null
> +++ b/Platform/Loongson/LoongArchQemuPkg/Library/StableTimerLib/TimerLib.c
> @@ -0,0 +1,262 @@
> +/** @file
> 
> +  Generic LoongArch implementation of TimerLib.h
> 
> +
> 
> +  Copyright (c) 2021 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;
> 
> +
> 
> +/**
> 
> +  Gets the timer count value.
> 
> +
> 
> +  @param[] VOID
> 
> +
> 
> +  @retval  timer count value.
> 
> +**/
> 
> +UINTN
> 
> +EFIAPI
> 
> +CsrReadTime (
> 
> +  VOID
> 
> +  )
> 
> +{
> 
> +  UINTN Value = 0;
> 
> +  __asm__ __volatile__(
> 
> +      " rdtime.d   %0, $r0\n"
> 
> +      : "=r" (Value));
> 
> +  return Value;
> 
> +}
> 
> +
> 
> +/**
> 
> +  Calculate the timer frequency.
> 
> +
> 
> +  @param[] VOID
> 
> +
> 
> +  @retval  Timer frequency.
> 
> +**/
> 
> +UINT32
> 
> +EFIAPI
> 
> +CalcConstFreq (
> 
> +  VOID
> 
> +  )
> 
> +{
> 
> +  UINT32 Result;
> 
> +  UINT32 BaseFreq;
> 
> +  UINT32 ClockMultiplier;
> 
> +  UINT32 ClockDivide;
> 
> +
> 
> +  LOONGARCH_GET_CPUCFG (BaseFreq, LOONGARCH_CPUCFG4);
> 
> +  LOONGARCH_GET_CPUCFG (Result, LOONGARCH_CPUCFG5);
> 
> +  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 = CsrReadTime ();
> 
> +  End = Start + Count;
> 
> +
> 
> +  do {
> 
> +    Ticks = CsrReadTime ();
> 
> +  } 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 CsrReadTime ();
> 
> +}
> 
> +/**
> 
> +  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;
> 
> +}
> 
> diff --git a/Platform/Loongson/LoongArchQemuPkg/Library/StableTimerLib/TimerLib.inf
> b/Platform/Loongson/LoongArchQemuPkg/Library/StableTimerLib/TimerLib.inf
> new file mode 100644
> index 0000000000..fef0fac08c
> --- /dev/null
> +++ b/Platform/Loongson/LoongArchQemuPkg/Library/StableTimerLib/TimerLib.inf
> @@ -0,0 +1,28 @@
> +## @file
> 
> +#  Generic LoongArch implementation of TimerLib.h
> 
> +#
> 
> +#  Copyright (c) 2021 Loongson Technology Corporation Limited. All rights reserved.<BR>
> 
> +#
> 
> +#  SPDX-License-Identifier: BSD-2-Clause-Patent
> 
> +#
> 
> +##
> 
> +
> 
> +[Defines]
> 
> +  INF_VERSION                       = 0x00010005
> 
> +  BASE_NAME                         = TimerLib
> 
> +  FILE_GUID                         = 740389C7-CC44-4A2F-88DC-89D97D312E7C
> 
> +  MODULE_TYPE                       = BASE
> 
> +  VERSION_STRING                    = 1.0
> 
> +  LIBRARY_CLASS                     = TimerLib
> 
> +
> 
> +[Sources.common]
> 
> +  TimerLib.c
> 
> +  Count.S
> 
> +
> 
> +[Packages]
> 
> +  Platform/Loongson/LoongArchQemuPkg/Loongson.dec
> 
> +  MdePkg/MdePkg.dec
> 
> +
> 
> +[LibraryClasses]
> 
> +  DebugLib
> 
> +  IoLib
> 
> --
> 2.31.1
> 
> 
> 
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