[RFC PATCH V2 07/19] MdePkg: Add ArchTimerLib library

["Sunil V L" <sunilvl@ventanamicro.com>]

This library implements the TimerLib.h functionality. This library
is similar to CpuTimerLib but needs the library constructor.

Signed-off-by: Sunil V L <sunilvl@ventanamicro.com>
---
 MdePkg/Library/ArchTimerLib/ArchTimerLib.inf      |  40 +++
 MdePkg/Library/ArchTimerLib/RiscV64/CpuTimerLib.c | 299 ++++++++++++++++++++
 MdePkg/Library/ArchTimerLib/ArchTimerLib.uni      |  14 +
 3 files changed, 353 insertions(+)

diff --git a/MdePkg/Library/ArchTimerLib/ArchTimerLib.inf b/MdePkg/Library/ArchTimerLib/ArchTimerLib.inf
new file mode 100644
index 000000000000..b61ae58d0142
--- /dev/null
+++ b/MdePkg/Library/ArchTimerLib/ArchTimerLib.inf
@@ -0,0 +1,40 @@
+## @file
+# Timer Library Instance which needs a constructor for the architecture.
+#
+#  Copyright (c) 2016 - 2019, Hewlett Packard Enterprise Development LP. All rights reserved.<BR>
+#  Copyright (c) 2022, Ventana Micro System Inc. All rights reserved.<BR>
+#
+#  SPDX-License-Identifier: BSD-2-Clause-Patent
+#
+##
+
+[Defines]
+  INF_VERSION          = 0x0001001b
+  BASE_NAME            = ArchTimerLib
+  FILE_GUID            = D3CF51A9-1CEA-4776-A8AB-CCFD14D7DAAF
+  MODULE_TYPE          = BASE
+  VERSION_STRING       = 1.0
+  LIBRARY_CLASS        = TimerLib
+  MODULE_UNI_FILE      = ArchTimerLib.uni
+  CONSTRUCTOR          = ArchTimerLibConstructor
+
+[Sources.RISCV64]
+  RiscV64/CpuTimerLib.c
+
+[Packages]
+  MdePkg/MdePkg.dec
+  MdeModulePkg/MdeModulePkg.dec
+  UefiCpuPkg/UefiCpuPkg.dec
+  EmbeddedPkg/EmbeddedPkg.dec
+
+[LibraryClasses]
+  BaseLib
+  DebugLib
+  FdtLib
+  HobLib
+
+[Pcd]
+  gUefiCpuPkgTokenSpaceGuid.PcdRiscVTimerFrequencyInHz  ## CONSUMES
+
+[Guids]
+  gFdtHobGuid
diff --git a/MdePkg/Library/ArchTimerLib/RiscV64/CpuTimerLib.c b/MdePkg/Library/ArchTimerLib/RiscV64/CpuTimerLib.c
new file mode 100644
index 000000000000..a81ac8c37cad
--- /dev/null
+++ b/MdePkg/Library/ArchTimerLib/RiscV64/CpuTimerLib.c
@@ -0,0 +1,299 @@
+/** @file
+  RISC-V instance of Timer Library.
+
+  Copyright (c) 2016 - 2022, Hewlett Packard Enterprise Development LP. All rights reserved.<BR>
+  Copyright (c) 2022, Ventana Micro Systems Inc. All rights reserved.<BR>
+
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#include <Uefi.h>
+#include <PiDxe.h>
+#include <Library/BaseLib.h>
+#include <Library/DebugLib.h>
+#include <Library/PcdLib.h>
+#include <Library/UefiDriverEntryPoint.h>
+#include <Library/UefiBootServicesTableLib.h>
+#include <Library/HobLib.h>
+#include <Guid/FdtHob.h>
+#include <Register/RiscV64/RiscVAsm.h>
+#include <Register/RiscV64/RiscVImpl.h>
+#include <libfdt.h>
+
+
+STATIC UINT32 mTimeBaseFrequency;
+STATIC BOOLEAN mTimeBaseFreqInitialized;
+
+UINT32
+InternalGetTimerFrequency(
+  VOID
+  )
+{
+  return mTimeBaseFrequency;
+}
+
+
+/**
+  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 = csr_read(CSR_TIME) + Delay;
+    Delay = 1 << (RISCV_TIMER_COMPARE_BITS - 2);
+    while (((Ticks - csr_read(CSR_TIME)) & (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,
+                InternalGetTimerFrequency()
+                ),
+              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,
+                InternalGetTimerFrequency()
+                ),
+              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)csr_read (CSR_TIME);
+}
+
+/**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 InternalGetTimerFrequency();
+}
+
+/**
+  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, InternalGetTimerFrequency(), &Remainder), 1000000000u);
+
+  //
+  // Frequency < 0x100000000, so Remainder < 0x100000000, then (Remainder * 1,000,000,000)
+  // will not overflow 64-bit.
+  //
+  NanoSeconds += DivU64x32 (MultU64x32 ((UINT64)Remainder, 1000000000u), InternalGetTimerFrequency());
+
+  return NanoSeconds;
+}
+
+STATIC
+RETURN_STATUS
+EFIAPI
+FdtInitializeTimerFrequency (
+  VOID
+  )
+{
+  VOID            *Hob;
+  VOID            *Fdt;
+  INT32           CpusNode, Len;
+  const fdt32_t   *Prop;
+
+  Hob = GetFirstGuidHob (&gFdtHobGuid);
+  if ((Hob == NULL) || (GET_GUID_HOB_DATA_SIZE (Hob) != sizeof (UINT64))) {
+    DEBUG ((DEBUG_ERROR, "%a: No FDT Hob found\n", __FUNCTION__));
+    return EFI_NOT_FOUND;
+  }
+
+  Fdt = (VOID *)(UINTN)*(UINT64 *)GET_GUID_HOB_DATA (Hob);
+
+  if (fdt_check_header (Fdt) != 0) {
+    DEBUG ((
+      DEBUG_ERROR,
+      "%a: No DTB found @ 0x%p\n",
+      __FUNCTION__,
+      Fdt
+      ));
+    return EFI_NOT_FOUND;
+  }
+
+  // The "cpus" node resides at the the root of the DT. Fetch it.
+  CpusNode = fdt_path_offset (Fdt, "/cpus");
+  if (CpusNode < 0) {
+    DEBUG ((DEBUG_ERROR, "%a: Invalid /cpus node\n", __FUNCTION__));
+    return EFI_NOT_FOUND;
+  }
+
+  Prop = fdt_getprop((void *)Fdt, CpusNode, "timebase-frequency", &Len);
+  if (!Prop) {
+    DEBUG ((DEBUG_ERROR, "%a: timebase-frequency propertynot found\n", __FUNCTION__));
+    return EFI_NOT_FOUND;
+  }
+
+  mTimeBaseFrequency = fdt32_to_cpu(*Prop);
+  DEBUG((DEBUG_INFO, "%a: Timer Frequency (DT) is set to 0x%x\n", __FUNCTION__, mTimeBaseFrequency));
+
+  return EFI_SUCCESS;
+}
+/**
+  Initializes the Timer Frequency by reading it from the DTB
+
+**/
+RETURN_STATUS
+EFIAPI
+ArchTimerLibConstructor (
+  VOID
+  )
+{
+  EFI_STATUS      Status;
+
+  /*
+   * Initialize only once
+   */
+  if (mTimeBaseFreqInitialized) {
+    return EFI_SUCCESS;
+  }
+
+  mTimeBaseFreqInitialized = 1;
+
+  Status = FdtInitializeTimerFrequency();
+
+  if (EFI_ERROR(Status)) {
+    mTimeBaseFrequency = PcdGet32 (PcdRiscVTimerFrequencyInHz);
+    DEBUG((DEBUG_INFO, "%a: Timer Frequency (PCD) is set to 0x%x\n", __FUNCTION__, mTimeBaseFrequency));
+  }
+
+  return EFI_SUCCESS;
+}
diff --git a/MdePkg/Library/ArchTimerLib/ArchTimerLib.uni b/MdePkg/Library/ArchTimerLib/ArchTimerLib.uni
new file mode 100644
index 000000000000..1c900bea42bf
--- /dev/null
+++ b/MdePkg/Library/ArchTimerLib/ArchTimerLib.uni
@@ -0,0 +1,14 @@
+// /** @file
+// Base CPU Timer Library
+//
+// Provides basic timer support using architecture specific methods.
+//
+// Copyright (c) 2022, Ventana Micro Systems Inc. All rights reserved.<BR>
+//
+// SPDX-License-Identifier: BSD-2-Clause-Patent
+//
+// **/
+
+#string STR_MODULE_ABSTRACT             #language en-US "CPU Timer Library"
+
+#string STR_MODULE_DESCRIPTION          #language en-US "Provides basic timer support using architecture specific methods"
-- 
2.25.1