[edk2-platforms][PATCH V5 06/15] Platform/Loongson: Add StableTimerLib.

["xianglai" <lixianglai@loongson.cn>]

This library provides a delay interface and a timing interface.

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=4054

Cc: Bibo Mao <maobibo@loongson.cn>
Cc: Chao Li <lichao@loongson.cn>
Cc: Leif Lindholm <quic_llindhol@quicinc.com>
Cc: Liming Gao <gaoliming@byosoft.com.cn>
Cc: Michael D Kinney <michael.d.kinney@intel.com>
Signed-off-by: xianglai li <lixianglai@loongson.cn>
---
 .../Include/Library/StableTimer.h             |  59 +++++
 .../Library/StableTimerLib/Count.S            |  52 ++++
 .../Library/StableTimerLib/TimerLib.c         | 236 ++++++++++++++++++
 .../Library/StableTimerLib/TimerLib.inf       |  32 +++
 4 files changed, 379 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..93f5b66c34
--- /dev/null
+++ b/Platform/Loongson/LoongArchQemuPkg/Include/Library/StableTimer.h
@@ -0,0 +1,59 @@
+/** @file
+
+  Copyright (c) 2022 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.
+**/
+extern
+UINTN
+EFIAPI
+LoongArchReadTime (
+  VOID
+  );
+
+/**
+  Calculate the timer frequency.
+
+  @param[] VOID
+
+  @retval  Timer frequency.
+**/
+UINT32
+EFIAPI
+CalcConstFreq (
+  VOID
+  );
+
+/*
+  Reads data from the specified CPUCFG register.
+
+  @param[OUT]  Val   Pointer to the variable used to store the CPUCFG register value.
+  @param[IN]  reg    Specifies the register number of the CPUCFG to read the data.
+
+  @retval  none
+ */
+extern
+VOID
+LoongArchReadCpuCfg (
+  UINT64   *Val,
+  UINT64   reg
+  );
+
+#endif // STABLE_TIMER_H_
diff --git a/Platform/Loongson/LoongArchQemuPkg/Library/StableTimerLib/Count.S b/Platform/Loongson/LoongArchQemuPkg/Library/StableTimerLib/Count.S
new file mode 100644
index 0000000000..4e0e718381
--- /dev/null
+++ b/Platform/Loongson/LoongArchQemuPkg/Library/StableTimerLib/Count.S
@@ -0,0 +1,52 @@
+#------------------------------------------------------------------------------
+#
+# Count for LoongArch
+#
+# Copyright (c) 2022 Loongson Technology Corporation Limited. All rights reserved.<BR>
+#
+# SPDX-License-Identifier: BSD-2-Clause-Patent
+#
+#------------------------------------------------------------------------------
+
+#ifndef __ASSEMBLY__
+#define __ASSEMBLY__
+#endif
+
+#include "Library/Cpu.h"
+
+ASM_GLOBAL ASM_PFX(CpuSetIP)
+ASM_GLOBAL ASM_PFX(LoongArchReadTime)
+ASM_GLOBAL ASM_PFX(LoongArchReadCpuCfg)
+
+#
+# Set cpu interrupts
+# @param A0 The interrupt number
+#
+
+ASM_PFX(CpuSetIP):
+    csrrd   T0, LOONGARCH_CSR_ECFG
+    or      T0, T0, A0
+    csrwr   T0, LOONGARCH_CSR_ECFG
+    jirl    ZERO, RA, 0
+
+#
+#Gets the timer count value.
+#@param[] VOID
+#@retval  timer count value.
+#
+
+ASM_PFX(LoongArchReadTime):
+    rdtime.d   A0, ZERO
+    jirl    ZERO, RA, 0
+
+#
+#   Read Csr CPUCFG register.
+#   @param   A0 Pointer to the variable used to store the CPUCFG register value.
+#   @param   A1 Specifies the register number of the CPUCFG to read the data.
+#   @retval  none
+#
+
+ASM_PFX(LoongArchReadCpuCfg):
+    cpucfg T0, A1
+    stptr.d T0, A0, 0
+    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..135fb22611
--- /dev/null
+++ b/Platform/Loongson/LoongArchQemuPkg/Library/StableTimerLib/TimerLib.c
@@ -0,0 +1,236 @@
+/** @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;
+}
diff --git a/Platform/Loongson/LoongArchQemuPkg/Library/StableTimerLib/TimerLib.inf b/Platform/Loongson/LoongArchQemuPkg/Library/StableTimerLib/TimerLib.inf
new file mode 100644
index 0000000000..86f243998b
--- /dev/null
+++ b/Platform/Loongson/LoongArchQemuPkg/Library/StableTimerLib/TimerLib.inf
@@ -0,0 +1,32 @@
+## @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
+#
+##
+
+[Defines]
+  INF_VERSION                       = 0x00010005
+  BASE_NAME                         = TimerLib
+  FILE_GUID                         = 740389C7-CC44-4A2F-88DC-89D97D312E7C
+  MODULE_TYPE                       = BASE
+  VERSION_STRING                    = 1.0
+  LIBRARY_CLASS                     = TimerLib
+
+#
+#  VALID_ARCHITECTURES           = LOONGARCH64
+#
+
+[Sources]
+  TimerLib.c
+  Count.S
+
+[Packages]
+  Platform/Loongson/LoongArchQemuPkg/Loongson.dec
+  MdePkg/MdePkg.dec
+
+[LibraryClasses]
+  DebugLib
+  IoLib
-- 
2.31.1