Re: [edk2-devel] [edk2-staging/RiscV64QemuVirt PATCH V4 20/34] UefiCpuPkg: Add CpuTimerDxe module

["Chang, Abner" <abner.chang@amd.com>]

[AMD Official Use Only - General]

Acked-by: Abner Chang <abner.chang@amd.com>

Need maintainer's agreement.
Abner

> -----Original Message-----
> From: devel@edk2.groups.io <devel@edk2.groups.io> On Behalf Of Sunil V L
> via groups.io
> Sent: Saturday, October 15, 2022 12:48 AM
> To: devel@edk2.groups.io
> Cc: Eric Dong <eric.dong@intel.com>; Ray Ni <ray.ni@intel.com>; Rahul
> Kumar <rahul1.kumar@intel.com>; Daniel Schaefer
> <git@danielschaefer.me>
> Subject: [edk2-devel] [edk2-staging/RiscV64QemuVirt PATCH V4 20/34]
> UefiCpuPkg: Add CpuTimerDxe module
> 
> Caution: This message originated from an External Source. Use proper
> caution when opening attachments, clicking links, or responding.
> 
> 
> REF:
> https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fbugz
> illa.tianocore.org%2Fshow_bug.cgi%3Fid%3D4076&amp;data=05%7C01%7Ca
> bner.chang%40amd.com%7Cb8b27a5b30864359da3408daae045448%7C3dd89
> 61fe4884e608e11a82d994e183d%7C0%7C0%7C638013630881288660%7CUnkn
> own%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik
> 1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&amp;sdata=Tuh%2BRGCWd
> YvjFXMWH%2FfEYRBoND5OhLWWk2VHINqUhb4%3D&amp;reserved=0
> 
> This DXE module initializes the timer interrupt handler and installs the Arch
> Timer protocol.
> 
> Cc: Eric Dong <eric.dong@intel.com>
> Cc: Ray Ni <ray.ni@intel.com>
> Cc: Rahul Kumar <rahul1.kumar@intel.com>
> Cc: Daniel Schaefer <git@danielschaefer.me>
> Signed-off-by: Sunil V L <sunilvl@ventanamicro.com>
> ---
>  UefiCpuPkg/UefiCpuPkg.dsc                |   3 +
>  UefiCpuPkg/CpuTimerDxe/CpuTimerDxe.inf   |  51 ++++
>  UefiCpuPkg/CpuTimerDxe/RiscV64/Timer.h   | 177 ++++++++++++
>  UefiCpuPkg/CpuTimerDxe/RiscV64/Timer.c   | 294 ++++++++++++++++++++
>  UefiCpuPkg/CpuTimerDxe/CpuTimer.uni      |  14 +
>  UefiCpuPkg/CpuTimerDxe/CpuTimerExtra.uni |  12 +
>  6 files changed, 551 insertions(+)
> 
> diff --git a/UefiCpuPkg/UefiCpuPkg.dsc b/UefiCpuPkg/UefiCpuPkg.dsc index
> 6ea90507e36f..54ef5edd6eae 100644
> --- a/UefiCpuPkg/UefiCpuPkg.dsc
> +++ b/UefiCpuPkg/UefiCpuPkg.dsc
> @@ -178,5 +178,8 @@ [Components.IA32, Components.X64]
>    UefiCpuPkg/Library/SmmCpuRendezvousLib/SmmCpuRendezvousLib.inf
>    UefiCpuPkg/Library/CpuPageTableLib/CpuPageTableLib.inf
> 
> +[Components.RISCV64]
> +  UefiCpuPkg/CpuTimerDxe/CpuTimerDxe.inf
> +
>  [BuildOptions]
>    *_*_*_CC_FLAGS = -D DISABLE_NEW_DEPRECATED_INTERFACES diff --git
> a/UefiCpuPkg/CpuTimerDxe/CpuTimerDxe.inf
> b/UefiCpuPkg/CpuTimerDxe/CpuTimerDxe.inf
> new file mode 100644
> index 000000000000..d7706328b591
> --- /dev/null
> +++ b/UefiCpuPkg/CpuTimerDxe/CpuTimerDxe.inf
> @@ -0,0 +1,51 @@
> +## @file
> +# Timer Arch protocol module
> +#
> +# Copyright (c) 2019, Hewlett Packard Enterprise Development LP. All
> +rights reserved.<BR> # # SPDX-License-Identifier: BSD-2-Clause-Patent #
> +##
> +
> +[Defines]
> +  INF_VERSION                    = 0x0001001b
> +  BASE_NAME                      = CpuTimerDxe
> +  MODULE_UNI_FILE                = CpuTimer.uni
> +  FILE_GUID                      = 055DDAC6-9142-4013-BF20-FC2E5BC325C9
> +  MODULE_TYPE                    = DXE_DRIVER
> +  VERSION_STRING                 = 1.0
> +  ENTRY_POINT                    = TimerDriverInitialize
> +#
> +# The following information is for reference only and not required by
> +the build # tools.
> +#
> +#  VALID_ARCHITECTURES           = RISCV64
> +#
> +[Packages]
> +  MdePkg/MdePkg.dec
> +  UefiCpuPkg/UefiCpuPkg.dec
> +
> +[LibraryClasses]
> +  BaseLib
> +  DebugLib
> +  IoLib
> +  CpuLib
> +  UefiBootServicesTableLib
> +  UefiDriverEntryPoint
> +
> +[LibraryClasses.RISCV64]
> +  RiscVSbiLib
> +
> +[Sources.RISCV64]
> +  RiscV64/Timer.h
> +  RiscV64/Timer.c
> +
> +[Protocols]
> +  gEfiCpuArchProtocolGuid       ## CONSUMES
> +  gEfiTimerArchProtocolGuid     ## PRODUCES
> +
> +[Depex]
> +  gEfiCpuArchProtocolGuid
> +
> +[UserExtensions.TianoCore."ExtraFiles"]
> +  CpuTimerExtra.uni
> diff --git a/UefiCpuPkg/CpuTimerDxe/RiscV64/Timer.h
> b/UefiCpuPkg/CpuTimerDxe/RiscV64/Timer.h
> new file mode 100644
> index 000000000000..586eb0cfadb4
> --- /dev/null
> +++ b/UefiCpuPkg/CpuTimerDxe/RiscV64/Timer.h
> @@ -0,0 +1,177 @@
> +/** @file
> +  RISC-V Timer Architectural Protocol definitions
> +
> +  Copyright (c) 2019, Hewlett Packard Enterprise Development LP. All
> + rights reserved.<BR>
> +
> +  SPDX-License-Identifier: BSD-2-Clause-Patent
> +
> +**/
> +
> +#ifndef TIMER_H_
> +#define TIMER_H_
> +
> +#include <PiDxe.h>
> +
> +#include <Protocol/Cpu.h>
> +#include <Protocol/Timer.h>
> +
> +#include <Library/UefiBootServicesTableLib.h>
> +#include <Library/BaseLib.h>
> +#include <Library/DebugLib.h>
> +#include <Library/IoLib.h>
> +
> +//
> +// RISC-V use 100us timer.
> +// The default timer tick duration is set to 10 ms = 10 * 1000 * 10 100
> +ns units // #define DEFAULT_TIMER_TICK_DURATION  100000
> +
> +extern VOID
> +RiscvSetTimerPeriod (
> +  UINT32  TimerPeriod
> +  );
> +
> +//
> +// Function Prototypes
> +//
> +
> +/**
> +  Initialize the Timer Architectural Protocol driver
> +
> +  @param ImageHandle     ImageHandle of the loaded driver
> +  @param SystemTable     Pointer to the System Table
> +
> +  @retval EFI_SUCCESS            Timer Architectural Protocol created
> +  @retval EFI_OUT_OF_RESOURCES   Not enough resources available to
> initialize driver.
> +  @retval EFI_DEVICE_ERROR       A device error occured attempting to
> initialize the driver.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +TimerDriverInitialize (
> +  IN EFI_HANDLE        ImageHandle,
> +  IN EFI_SYSTEM_TABLE  *SystemTable
> +  )
> +;
> +
> +/**
> +
> +  This function adjusts the period of timer interrupts to the value
> + specified  by TimerPeriod.  If the timer period is updated, then the
> + selected timer  period is stored in EFI_TIMER.TimerPeriod, and
> + EFI_SUCCESS is returned.  If  the timer hardware is not programmable, then
> EFI_UNSUPPORTED is returned.
> +  If an error occurs while attempting to update the timer period, then
> + the  timer hardware will be put back in its state prior to this call,
> + and  EFI_DEVICE_ERROR is returned.  If TimerPeriod is 0, then the
> + timer interrupt  is disabled.  This is not the same as disabling the CPU's
> interrupts.
> +  Instead, it must either turn off the timer hardware, or it must
> + adjust the  interrupt controller so that a CPU interrupt is not
> + generated when the timer  interrupt fires.
> +
> +
> +  @param This            The EFI_TIMER_ARCH_PROTOCOL instance.
> +  @param NotifyFunction  The rate to program the timer interrupt in 100 nS
> units.  If
> +                         the timer hardware is not programmable, then
> EFI_UNSUPPORTED is
> +                         returned.  If the timer is programmable, then the timer period
> +                         will be rounded up to the nearest timer period that is
> supported
> +                         by the timer hardware.  If TimerPeriod is set to 0, then the
> +                         timer interrupts will be disabled.
> +
> +  @retval        EFI_SUCCESS       The timer period was changed.
> +  @retval        EFI_UNSUPPORTED   The platform cannot change the period of
> the timer interrupt.
> +  @retval        EFI_DEVICE_ERROR  The timer period could not be changed
> due to a device error.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +TimerDriverRegisterHandler (
> +  IN EFI_TIMER_ARCH_PROTOCOL  *This,
> +  IN EFI_TIMER_NOTIFY         NotifyFunction
> +  )
> +;
> +
> +/**
> +
> +  This function adjusts the period of timer interrupts to the value
> + specified  by TimerPeriod.  If the timer period is updated, then the
> + selected timer  period is stored in EFI_TIMER.TimerPeriod, and
> + EFI_SUCCESS is returned.  If  the timer hardware is not programmable, then
> EFI_UNSUPPORTED is returned.
> +  If an error occurs while attempting to update the timer period, then
> + the  timer hardware will be put back in its state prior to this call,
> + and  EFI_DEVICE_ERROR is returned.  If TimerPeriod is 0, then the
> + timer interrupt  is disabled.  This is not the same as disabling the CPU's
> interrupts.
> +  Instead, it must either turn off the timer hardware, or it must
> + adjust the  interrupt controller so that a CPU interrupt is not
> + generated when the timer  interrupt fires.
> +
> +
> +  @param This            The EFI_TIMER_ARCH_PROTOCOL instance.
> +  @param TimerPeriod     The rate to program the timer interrupt in 100 nS
> units.  If
> +                         the timer hardware is not programmable, then
> EFI_UNSUPPORTED is
> +                         returned.  If the timer is programmable, then the timer period
> +                         will be rounded up to the nearest timer period that is
> supported
> +                         by the timer hardware.  If TimerPeriod is set to 0, then the
> +                         timer interrupts will be disabled.
> +
> +  @retval        EFI_SUCCESS       The timer period was changed.
> +  @retval        EFI_UNSUPPORTED   The platform cannot change the period of
> the timer interrupt.
> +  @retval        EFI_DEVICE_ERROR  The timer period could not be changed
> due to a device error.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +TimerDriverSetTimerPeriod (
> +  IN EFI_TIMER_ARCH_PROTOCOL  *This,
> +  IN UINT64                   TimerPeriod
> +  )
> +;
> +
> +/**
> +
> +  This function retrieves the period of timer interrupts in 100 ns
> + units,  returns that value in TimerPeriod, and returns EFI_SUCCESS.
> + If TimerPeriod  is NULL, then EFI_INVALID_PARAMETER is returned.  If a
> + TimerPeriod of 0 is  returned, then the timer is currently disabled.
> +
> +
> +  @param This            The EFI_TIMER_ARCH_PROTOCOL instance.
> +  @param TimerPeriod     A pointer to the timer period to retrieve in 100 ns
> units.  If
> +                         0 is returned, then the timer is currently disabled.
> +
> +  @retval EFI_SUCCESS            The timer period was returned in TimerPeriod.
> +  @retval EFI_INVALID_PARAMETER  TimerPeriod is NULL.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +TimerDriverGetTimerPeriod (
> +  IN EFI_TIMER_ARCH_PROTOCOL  *This,
> +  OUT UINT64                  *TimerPeriod
> +  )
> +;
> +
> +/**
> +
> +  This function generates a soft timer interrupt. If the platform does
> + not support soft  timer interrupts, then EFI_UNSUPPORTED is returned.
> Otherwise, EFI_SUCCESS is returned.
> +  If a handler has been registered through the
> + EFI_TIMER_ARCH_PROTOCOL.RegisterHandler()
> +  service, then a soft timer interrupt will be generated. If the timer
> + interrupt is  enabled when this service is called, then the registered
> + handler will be invoked. The  registered handler should not be able to
> + distinguish a hardware-generated timer  interrupt from a software-
> generated timer interrupt.
> +
> +
> +  @param This              The EFI_TIMER_ARCH_PROTOCOL instance.
> +
> +  @retval EFI_SUCCESS       The soft timer interrupt was generated.
> +  @retval EFI_UNSUPPORTEDT  The platform does not support the
> generation of soft timer interrupts.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +TimerDriverGenerateSoftInterrupt (
> +  IN EFI_TIMER_ARCH_PROTOCOL  *This
> +  )
> +;
> +
> +#endif
> diff --git a/UefiCpuPkg/CpuTimerDxe/RiscV64/Timer.c
> b/UefiCpuPkg/CpuTimerDxe/RiscV64/Timer.c
> new file mode 100644
> index 000000000000..db153f715e60
> --- /dev/null
> +++ b/UefiCpuPkg/CpuTimerDxe/RiscV64/Timer.c
> @@ -0,0 +1,294 @@
> +/** @file
> +  RISC-V Timer Architectural Protocol
> +
> +  Copyright (c) 2019, Hewlett Packard Enterprise Development LP. All
> + rights reserved.<BR>
> +
> +  SPDX-License-Identifier: BSD-2-Clause-Patent
> +
> +**/
> +
> +#include <Library/BaseLib.h>
> +#include <Library/BaseRiscVSbiLib.h>
> +#include "Timer.h"
> +
> +//
> +// The handle onto which the Timer Architectural Protocol will be
> +installed // STATIC EFI_HANDLE  mTimerHandle = NULL;
> +
> +//
> +// The Timer Architectural Protocol that this driver produces //
> +EFI_TIMER_ARCH_PROTOCOL  mTimer = {
> +  TimerDriverRegisterHandler,
> +  TimerDriverSetTimerPeriod,
> +  TimerDriverGetTimerPeriod,
> +  TimerDriverGenerateSoftInterrupt
> +};
> +
> +//
> +// Pointer to the CPU Architectural Protocol instance //
> +EFI_CPU_ARCH_PROTOCOL  *mCpu;
> +
> +//
> +// The notification function to call on every timer interrupt.
> +// A bug in the compiler prevents us from initializing this here.
> +//
> +STATIC EFI_TIMER_NOTIFY  mTimerNotifyFunction;
> +
> +//
> +// The current period of the timer interrupt // STATIC UINT64
> +mTimerPeriod = 0;
> +
> +/**
> +  Timer Interrupt Handler.
> +
> +  @param InterruptType    The type of interrupt that occured
> +  @param SystemContext    A pointer to the system context when the
> interrupt occured
> +**/
> +VOID
> +EFIAPI
> +TimerInterruptHandler (
> +  IN EFI_EXCEPTION_TYPE  InterruptType,
> +  IN EFI_SYSTEM_CONTEXT  SystemContext
> +  )
> +{
> +  EFI_TPL  OriginalTPL;
> +  UINT64   RiscvTimer;
> +
> +  OriginalTPL = gBS->RaiseTPL (TPL_HIGH_LEVEL);  if
> + (mTimerNotifyFunction != NULL) {
> +    mTimerNotifyFunction (mTimerPeriod);  }
> +
> +  RiscVDisableTimerInterrupt (); // Disable SMode timer int
> + RiscVClearPendingTimerInterrupt ();  if (mTimerPeriod == 0) {
> +    gBS->RestoreTPL (OriginalTPL);
> +    RiscVDisableTimerInterrupt (); // Disable SMode timer int
> +    return;
> +  }
> +
> +  RiscvTimer               = RiscVReadTimer ();
> +  SbiSetTimer (RiscvTimer += mTimerPeriod);
> +  gBS->RestoreTPL (OriginalTPL);
> +  RiscVEnableTimerInterrupt (); // enable SMode timer int }
> +
> +/**
> +
> +  This function registers the handler NotifyFunction so it is called
> + every time  the timer interrupt fires.  It also passes the amount of
> + time since the last  handler call to the NotifyFunction.  If
> + NotifyFunction is NULL, then the  handler is unregistered.  If the
> + handler is registered, then EFI_SUCCESS is  returned.  If the CPU does
> + not support registering a timer interrupt handler,  then
> + EFI_UNSUPPORTED is returned.  If an attempt is made to register a handler
> when a handler is already registered, then EFI_ALREADY_STARTED is
> returned.
> +  If an attempt is made to unregister a handler when a handler is not
> + registered,  then EFI_INVALID_PARAMETER is returned.  If an error
> + occurs attempting to  register the NotifyFunction with the timer
> + interrupt, then EFI_DEVICE_ERROR  is returned.
> +
> +  @param This             The EFI_TIMER_ARCH_PROTOCOL instance.
> +  @param NotifyFunction   The function to call when a timer interrupt fires.
> This
> +                          function executes at TPL_HIGH_LEVEL.  The DXE Core will
> +                          register a handler for the timer interrupt, so it can know
> +                          how much time has passed.  This information is used to
> +                          signal timer based events.  NULL will unregister the handler.
> +
> +  @retval        EFI_SUCCESS            The timer handler was registered.
> +  @retval        EFI_UNSUPPORTED        The platform does not support timer
> interrupts.
> +  @retval        EFI_ALREADY_STARTED    NotifyFunction is not NULL, and a
> handler is already
> +                                        registered.
> +  @retval        EFI_INVALID_PARAMETER  NotifyFunction is NULL, and a
> handler was not
> +                                        previously registered.
> +  @retval        EFI_DEVICE_ERROR       The timer handler could not be
> registered.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +TimerDriverRegisterHandler (
> +  IN EFI_TIMER_ARCH_PROTOCOL  *This,
> +  IN EFI_TIMER_NOTIFY         NotifyFunction
> +  )
> +{
> +  DEBUG ((DEBUG_INFO, "TimerDriverRegisterHandler(0x%lx) called\n",
> +NotifyFunction));
> +  mTimerNotifyFunction = NotifyFunction;
> +  return EFI_SUCCESS;
> +}
> +
> +/**
> +
> +  This function adjusts the period of timer interrupts to the value
> + specified  by TimerPeriod.  If the timer period is updated, then the
> + selected timer  period is stored in EFI_TIMER.TimerPeriod, and
> + EFI_SUCCESS is returned.  If  the timer hardware is not programmable, then
> EFI_UNSUPPORTED is returned.
> +  If an error occurs while attempting to update the timer period, then
> + the  timer hardware will be put back in its state prior to this call,
> + and  EFI_DEVICE_ERROR is returned.  If TimerPeriod is 0, then the
> + timer interrupt  is disabled.  This is not the same as disabling the CPU's
> interrupts.
> +  Instead, it must either turn off the timer hardware, or it must
> + adjust the  interrupt controller so that a CPU interrupt is not
> + generated when the timer  interrupt fires.
> +
> +
> +  @param This            The EFI_TIMER_ARCH_PROTOCOL instance.
> +  @param TimerPeriod     The rate to program the timer interrupt in 100 nS
> units.  If
> +                         the timer hardware is not programmable, then
> EFI_UNSUPPORTED is
> +                         returned.  If the timer is programmable, then the timer period
> +                         will be rounded up to the nearest timer period that is
> supported
> +                         by the timer hardware.  If TimerPeriod is set to 0, then the
> +                         timer interrupts will be disabled.
> +
> +  @retval        EFI_SUCCESS       The timer period was changed.
> +  @retval        EFI_UNSUPPORTED   The platform cannot change the period of
> the timer interrupt.
> +  @retval        EFI_DEVICE_ERROR  The timer period could not be changed
> due to a device error.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +TimerDriverSetTimerPeriod (
> +  IN EFI_TIMER_ARCH_PROTOCOL  *This,
> +  IN UINT64                   TimerPeriod
> +  )
> +{
> +  UINT64  RiscvTimer;
> +
> +  DEBUG ((DEBUG_INFO, "TimerDriverSetTimerPeriod(0x%lx)\n",
> + TimerPeriod));
> +
> +  if (TimerPeriod == 0) {
> +    mTimerPeriod = 0;
> +    RiscVDisableTimerInterrupt (); // Disable SMode timer int
> +    return EFI_SUCCESS;
> +  }
> +
> +  mTimerPeriod = TimerPeriod / 10; // convert unit from 100ns to 1us
> +  RiscvTimer   = RiscVReadTimer ();
> +  SbiSetTimer (RiscvTimer + mTimerPeriod);
> +
> +  mCpu->EnableInterrupt (mCpu);
> +  RiscVEnableTimerInterrupt (); // enable SMode timer int
> +  return EFI_SUCCESS;
> +}
> +
> +/**
> +
> +  This function retrieves the period of timer interrupts in 100 ns
> + units,  returns that value in TimerPeriod, and returns EFI_SUCCESS.
> + If TimerPeriod  is NULL, then EFI_INVALID_PARAMETER is returned.  If a
> + TimerPeriod of 0 is  returned, then the timer is currently disabled.
> +
> +
> +  @param This            The EFI_TIMER_ARCH_PROTOCOL instance.
> +  @param TimerPeriod     A pointer to the timer period to retrieve in 100 ns
> units.  If
> +                         0 is returned, then the timer is currently disabled.
> +
> +  @retval EFI_SUCCESS            The timer period was returned in TimerPeriod.
> +  @retval EFI_INVALID_PARAMETER  TimerPeriod is NULL.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +TimerDriverGetTimerPeriod (
> +  IN EFI_TIMER_ARCH_PROTOCOL  *This,
> +  OUT UINT64                  *TimerPeriod
> +  )
> +{
> +  *TimerPeriod = mTimerPeriod;
> +  return EFI_SUCCESS;
> +}
> +
> +/**
> +
> +  This function generates a soft timer interrupt. If the platform does
> + not support soft  timer interrupts, then EFI_UNSUPPORTED is returned.
> Otherwise, EFI_SUCCESS is returned.
> +  If a handler has been registered through the
> + EFI_TIMER_ARCH_PROTOCOL.RegisterHandler()
> +  service, then a soft timer interrupt will be generated. If the timer
> + interrupt is  enabled when this service is called, then the registered
> + handler will be invoked. The  registered handler should not be able to
> + distinguish a hardware-generated timer  interrupt from a software-
> generated timer interrupt.
> +
> +
> +  @param This              The EFI_TIMER_ARCH_PROTOCOL instance.
> +
> +  @retval EFI_SUCCESS       The soft timer interrupt was generated.
> +  @retval EFI_UNSUPPORTEDT  The platform does not support the
> generation of soft timer interrupts.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +TimerDriverGenerateSoftInterrupt (
> +  IN EFI_TIMER_ARCH_PROTOCOL  *This
> +  )
> +{
> +  return EFI_SUCCESS;
> +}
> +
> +/**
> +  Initialize the Timer Architectural Protocol driver
> +
> +  @param ImageHandle     ImageHandle of the loaded driver
> +  @param SystemTable     Pointer to the System Table
> +
> +  @retval EFI_SUCCESS            Timer Architectural Protocol created
> +  @retval EFI_OUT_OF_RESOURCES   Not enough resources available to
> initialize driver.
> +  @retval EFI_DEVICE_ERROR       A device error occured attempting to
> initialize the driver.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +TimerDriverInitialize (
> +  IN EFI_HANDLE        ImageHandle,
> +  IN EFI_SYSTEM_TABLE  *SystemTable
> +  )
> +{
> +  EFI_STATUS  Status;
> +
> +  //
> +  // Initialize the pointer to our notify function.
> +  //
> +  mTimerNotifyFunction = NULL;
> +
> +  //
> +  // Make sure the Timer Architectural Protocol is not already
> + installed in the system  //  ASSERT_PROTOCOL_ALREADY_INSTALLED (NULL,
> + &gEfiTimerArchProtocolGuid);
> +
> +  //
> +  // Find the CPU architectural protocol.
> +  //
> +  Status = gBS->LocateProtocol (&gEfiCpuArchProtocolGuid, NULL, (VOID
> + **)&mCpu);  ASSERT_EFI_ERROR (Status);
> +
> +  //
> +  // Force the timer to be disabled
> +  //
> +  Status = TimerDriverSetTimerPeriod (&mTimer, 0);  ASSERT_EFI_ERROR
> + (Status);
> +
> +  //
> +  // Install interrupt handler for RISC-V Timer.
> +  //
> +  Status = mCpu->RegisterInterruptHandler (mCpu,
> + EXCEPT_RISCV_TIMER_INT, TimerInterruptHandler);  ASSERT_EFI_ERROR
> + (Status);
> +
> +  //
> +  // Force the timer to be enabled at its default period  //  Status =
> + TimerDriverSetTimerPeriod (&mTimer, DEFAULT_TIMER_TICK_DURATION);
> + ASSERT_EFI_ERROR (Status);
> +
> +  //
> +  // Install the Timer Architectural Protocol onto a new handle
> +  //
> +  Status = gBS->InstallMultipleProtocolInterfaces (
> +                  &mTimerHandle,
> +                  &gEfiTimerArchProtocolGuid,
> +                  &mTimer,
> +                  NULL
> +                  );
> +  ASSERT_EFI_ERROR (Status);
> +  return Status;
> +}
> diff --git a/UefiCpuPkg/CpuTimerDxe/CpuTimer.uni
> b/UefiCpuPkg/CpuTimerDxe/CpuTimer.uni
> new file mode 100644
> index 000000000000..76de1f3f352a
> --- /dev/null
> +++ b/UefiCpuPkg/CpuTimerDxe/CpuTimer.uni
> @@ -0,0 +1,14 @@
> +// /** @file
> +//
> +// Timer Arch protocol strings.
> +//
> +// Copyright (c) 2016, Hewlett Packard Enterprise Development LP. All
> +rights reserved.<BR> // // SPDX-License-Identifier: BSD-2-Clause-Patent
> +// // **/
> +
> +
> +#string STR_MODULE_ABSTRACT             #language en-US "Timer driver that
> provides Timer Arch protocol"
> +
> +#string STR_MODULE_DESCRIPTION          #language en-US "Timer driver
> that provides Timer Arch protocol."
> diff --git a/UefiCpuPkg/CpuTimerDxe/CpuTimerExtra.uni
> b/UefiCpuPkg/CpuTimerDxe/CpuTimerExtra.uni
> new file mode 100644
> index 000000000000..ceb93a7ce82f
> --- /dev/null
> +++ b/UefiCpuPkg/CpuTimerDxe/CpuTimerExtra.uni
> @@ -0,0 +1,12 @@
> +// /** @file
> +// Timer Localized Strings and Content
> +//
> +// Copyright (c) 2016, Hewlett Packard Enterprise Development LP. All
> +rights reserved.<BR> // // SPDX-License-Identifier: BSD-2-Clause-Patent
> +// // **/
> +
> +#string STR_PROPERTIES_MODULE_NAME
> +#language en-US
> +"Timer DXE Driver"
> --
> 2.38.0
> 
> 
> 
> 
>