Re: [edk2-devel] [PATCH v4 10/37] UefiCpuPkg: Add LoongArch64 CPU Timer library

["Ni, Ray" <ray.ni@intel.com>]

Acked-by: Ray Ni <ray.ni@intel.com>

Thanks,
Ray
> -----Original Message-----
> From: Chao Li <lichao@loongson.cn>
> Sent: Tuesday, December 12, 2023 9:12 PM
> To: devel@edk2.groups.io
> Cc: Dong, Eric <eric.dong@intel.com>; Ni, Ray <ray.ni@intel.com>; Kumar,
> Rahul R <rahul.r.kumar@intel.com>; Gerd Hoffmann <kraxel@redhat.com>
> Subject: [PATCH v4 10/37] UefiCpuPkg: Add LoongArch64 CPU Timer library
> 
> Add the LoongArch64 CPU Timer library, using CPUCFG 0x4 and 0x5 for
> Stable Counter frequency.
> 
> BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=4584
> 
> Cc: Eric Dong <eric.dong@intel.com>
> Cc: Ray Ni <ray.ni@intel.com>
> Cc: Rahul Kumar <rahul1.kumar@intel.com>
> Cc: Gerd Hoffmann <kraxel@redhat.com>
> Signed-off-by: Chao Li <lichao@loongson.cn>
> ---
>  .../BaseLoongArch64CpuTimerLib.inf            |  29 ++
>  .../BaseLoongArch64CpuTimerLib.uni            |  15 ++
>  .../BaseLoongArch64CpuTimerLib/CpuTimerLib.c  | 251
> ++++++++++++++++++
>  UefiCpuPkg/UefiCpuPkg.dsc                     |   3 +
>  4 files changed, 298 insertions(+)
>  create mode 100644
> UefiCpuPkg/Library/BaseLoongArch64CpuTimerLib/BaseLoongArch64CpuTim
> erLib.inf
>  create mode 100644
> UefiCpuPkg/Library/BaseLoongArch64CpuTimerLib/BaseLoongArch64CpuTim
> erLib.uni
>  create mode 100644
> UefiCpuPkg/Library/BaseLoongArch64CpuTimerLib/CpuTimerLib.c
> 
> diff --git
> a/UefiCpuPkg/Library/BaseLoongArch64CpuTimerLib/BaseLoongArch64CpuT
> imerLib.inf
> b/UefiCpuPkg/Library/BaseLoongArch64CpuTimerLib/BaseLoongArch64CpuT
> imerLib.inf
> new file mode 100644
> index 0000000000..ab94d91858
> --- /dev/null
> +++
> b/UefiCpuPkg/Library/BaseLoongArch64CpuTimerLib/BaseLoongArch64CpuT
> imerLib.inf
> @@ -0,0 +1,29 @@
> +## @file
> +#  Base CPU Timer Library
> +#
> +#  Provides base timer support using CPUCFG 0x4 and 0x5 stable counter
> frequency.
> +#
> +#  Copyright (c) 2023, Loongson Technology Corporation Limited. All rights
> reserved.<BR>
> +#  SPDX-License-Identifier: BSD-2-Clause-Patent
> +#
> +##
> +
> +[Defines]
> +  INF_VERSION                       = 0x00010029
> +  BASE_NAME                         =
> BaseLoongArch64CpuTimerLib
> +  FILE_GUID                         =
> 740389C7-CC44-4A2F-88DC-89D97D312E7C
> +  MODULE_TYPE                       = BASE
> +  VERSION_STRING                    = 1.0
> +  LIBRARY_CLASS                     = TimerLib
> +  MODULE_UNI_FILE                   =
> BaseLoongArch64CpuTimerLib.uni
> +
> +[Sources]
> +  CpuTimerLib.c
> +
> +[Packages]
> +  MdePkg/MdePkg.dec
> +
> +[LibraryClasses]
> +  BaseLib
> +  DebugLib
> +  SafeIntLib
> diff --git
> a/UefiCpuPkg/Library/BaseLoongArch64CpuTimerLib/BaseLoongArch64CpuT
> imerLib.uni
> b/UefiCpuPkg/Library/BaseLoongArch64CpuTimerLib/BaseLoongArch64CpuT
> imerLib.uni
> new file mode 100644
> index 0000000000..72d38ec679
> --- /dev/null
> +++
> b/UefiCpuPkg/Library/BaseLoongArch64CpuTimerLib/BaseLoongArch64CpuT
> imerLib.uni
> @@ -0,0 +1,15 @@
> +// /** @file
> +// Base CPU Timer Library
> +//
> +// Provides base timer support using CPUCFG 0x4 and 0x5 stable counter
> frequency.
> +//
> +// Copyright (c) 2023, Loongson Technology Corporation Limited. All rights
> reserved.<BR>
> +//
> +// SPDX-License-Identifier: BSD-2-Clause-Patent
> +//
> +// **/
> +
> +
> +#string STR_MODULE_ABSTRACT             #language en-US
> "LOONGARCH CPU Timer Library"
> +
> +#string STR_MODULE_DESCRIPTION          #language en-US "Provides
> basic timer support using CPUCFG 0x4 and 0x5 stable counter frequency."
> diff --git a/UefiCpuPkg/Library/BaseLoongArch64CpuTimerLib/CpuTimerLib.c
> b/UefiCpuPkg/Library/BaseLoongArch64CpuTimerLib/CpuTimerLib.c
> new file mode 100644
> index 0000000000..828ca4a51a
> --- /dev/null
> +++ b/UefiCpuPkg/Library/BaseLoongArch64CpuTimerLib/CpuTimerLib.c
> @@ -0,0 +1,251 @@
> +/** @file
> +  CPUCFG 0x4 and 0x5 for Stable Counter frequency instance of Timer
> Library.
> +
> +  Copyright (c) 2023, Loongson Technology Corporation Limited. All rights
> reserved.<BR>
> +
> +  SPDX-License-Identifier: BSD-2-Clause-Patent
> +**/
> +
> +#include <Base.h>
> +#include <Library/BaseLib.h>
> +#include <Library/DebugLib.h>
> +#include <Library/SafeIntLib.h>
> +#include <Library/TimerLib.h>
> +#include <Register/LoongArch64/Cpucfg.h>
> +
> +/**
> +  Calculate clock frequency using CPUCFG 0x4 and 0x5 registers.
> +
> +  @param  VOID.
> +
> +  @return The frequency in Hz.
> +
> +**/
> +STATIC
> +UINT64
> +CalcConstFreq (
> +  VOID
> +  )
> +{
> +  UINT32                 BaseFreq;
> +  UINT64                 ClockMultiplier;
> +  UINT32                 ClockDivide;
> +  CPUCFG_REG4_INFO_DATA  CcFreq;
> +  CPUCFG_REG5_INFO_DATA  CpucfgReg5Data;
> +  UINT64                 StableTimerFreq;
> +
> +  //
> +  // Get the the crystal frequency corresponding to the constant
> +  // frequency timer and the clock used by the timer.
> +  //
> +  AsmCpucfg (CPUCFG_REG4_INFO, &CcFreq.Uint32);
> +
> +  //
> +  // Get the multiplication factor and frequency division factor
> +  // corresponding to the constant frequency timer and the clock
> +  // used by the timer.
> +  //
> +  AsmCpucfg (CPUCFG_REG5_INFO, &CpucfgReg5Data.Uint32);
> +
> +  BaseFreq        = CcFreq.Bits.CC_FREQ;
> +  ClockMultiplier = CpucfgReg5Data.Bits.CC_MUL & 0xFFFF;
> +  ClockDivide     = CpucfgReg5Data.Bits.CC_DIV & 0xFFFF;
> +
> +  if ((BaseFreq == 0x0) || (ClockMultiplier == 0x0) || (ClockDivide == 0x0)) {
> +    DEBUG ((
> +      DEBUG_ERROR,
> +      "LoongArch Stable Timer is not available in the CPU, hence this
> library cannot be used.\n"
> +      ));
> +    ASSERT (FALSE);
> +    CpuDeadLoop ();
> +  }
> +
> +  StableTimerFreq = ((ClockMultiplier * BaseFreq) / ClockDivide);
> +
> +  if (StableTimerFreq == 0x0) {
> +    ASSERT (FALSE);
> +  }
> +
> +  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
> +  )
> +{
> +  UINT64         CurrentTicks, ExceptedTicks, Remaining;
> +  RETURN_STATUS  Status;
> +
> +  Status = SafeUint64Mult (MicroSeconds, CalcConstFreq (), &Remaining);
> +  ASSERT_RETURN_ERROR(Status);
> +
> +  ExceptedTicks  = DivU64x32 (Remaining, 1000000U);
> +  CurrentTicks   = AsmReadStableCounter ();
> +  ExceptedTicks += CurrentTicks;
> +
> +  do {
> +    CurrentTicks = AsmReadStableCounter ();
> +  } while (CurrentTicks < ExceptedTicks);
> +
> +  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
> +  )
> +{
> +  UINTN  MicroSeconds;
> +
> +  // Round up to 1us Tick Number
> +  MicroSeconds  = NanoSeconds / 1000;
> +  MicroSeconds += ((NanoSeconds % 1000) == 0) ? 0 : 1;
> +
> +  MicroSecondDelay (MicroSeconds);
> +
> +  return NanoSeconds;
> +}
> +
> +/**
> +  Retrieves the current value of a 64-bit free running Stable Counter.
> +
> +  The LoongArch defines a constant frequency timer, whose main body is a
> +  64-bit counter called StableCounter. StableCounter is set to 0 after
> +  reset, and then increments by 1 every counting clock cycle. When the
> +  count reaches all 1s, it automatically wraps around to 0 and continues
> +  to increment.
> +  The properties of the Stable Counter can be retrieved from
> +  GetPerformanceCounterProperties().
> +
> +  @return The current value of the Stable Counter.
> +
> +**/
> +UINT64
> +EFIAPI
> +GetPerformanceCounter (
> +  VOID
> +  )
> +{
> +  //
> +  // Just return the value of Stable Counter.
> +  //
> +  return AsmReadStableCounter ();
> +}
> +
> +/**
> +  Retrieves the 64-bit frequency in Hz and the range of Stable Counter
> +  values.
> +
> +  If StartValue is not NULL, then the value that the stbale counter starts
> +  with immediately after is it rolls over is returned in StartValue. If
> +  EndValue is not NULL, then the value that the stable counter end with
> +  immediately before it rolls over is returned in EndValue. The 64-bit
> +  frequency of the system frequency in Hz is always returned.
> +
> +  @param  StartValue  The value the stable counter starts with when it
> +                      rolls over.
> +  @param  EndValue    The value that the stable 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 = 0xFFFFFFFFFFFFFFFFULL;
> +  }
> +
> +  return CalcConstFreq ();
> +}
> +
> +/**
> +  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;
> +  RETURN_STATUS  Status;
> +
> +  Frequency = GetPerformanceCounterProperties (NULL, NULL);
> +
> +  //
> +  //          Ticks
> +  // Time = --------- x 1,000,000,000
> +  //        Frequency
> +  //
> +  Status = SafeUint64Mult (
> +             DivU64x64Remainder (Ticks, Frequency, &Remainder),
> +             1000000000u,
> +             &NanoSeconds
> +             );
> +
> +  //
> +  // 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);
> +
> +  Status = SafeUint64Add (
> +             NanoSeconds,
> +             DivU64x64Remainder (
> +               MultU64x32 (Remainder, 1000000000u),
> +               Frequency,
> +               NULL
> +               ),
> +             &NanoSeconds
> +             );
> +  ASSERT_RETURN_ERROR(Status);
> +
> +  return NanoSeconds;
> +}
> diff --git a/UefiCpuPkg/UefiCpuPkg.dsc b/UefiCpuPkg/UefiCpuPkg.dsc
> index 074fd77461..8e34a9cd6b 100644
> --- a/UefiCpuPkg/UefiCpuPkg.dsc
> +++ b/UefiCpuPkg/UefiCpuPkg.dsc
> @@ -205,5 +205,8 @@
>    UefiCpuPkg/CpuTimerDxeRiscV64/CpuTimerDxeRiscV64.inf
>    UefiCpuPkg/CpuDxeRiscV64/CpuDxeRiscV64.inf
> 
> +[Components.LOONGARCH64]
> +
> UefiCpuPkg/Library/BaseLoongArch64CpuTimerLib/BaseLoongArch64CpuTim
> erLib.inf
> +
>  [BuildOptions]
>    *_*_*_CC_FLAGS = -D DISABLE_NEW_DEPRECATED_INTERFACES
> --
> 2.27.0



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