[RFC PATCH V2 17/19] MdeModulePkg/Universal: Add TimerDxe module

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

This DXE module initializes the timer interrupt handler
and installs the Arch Timer protocol.

Signed-off-by: Sunil V L <sunilvl@ventanamicro.com>
---
 MdeModulePkg/Universal/TimerDxe/TimerDxe.inf    |  52 ++++
 MdeModulePkg/Universal/TimerDxe/RiscV64/Timer.h | 174 ++++++++++++
 MdeModulePkg/Universal/TimerDxe/RiscV64/Timer.c | 293 ++++++++++++++++++++
 MdeModulePkg/Universal/TimerDxe/Timer.uni       |  15 +
 MdeModulePkg/Universal/TimerDxe/TimerExtra.uni  |  13 +
 5 files changed, 547 insertions(+)

diff --git a/MdeModulePkg/Universal/TimerDxe/TimerDxe.inf b/MdeModulePkg/Universal/TimerDxe/TimerDxe.inf
new file mode 100644
index 000000000000..b291a1fcecb2
--- /dev/null
+++ b/MdeModulePkg/Universal/TimerDxe/TimerDxe.inf
@@ -0,0 +1,52 @@
+## @file
+# Timer Arch protocol module
+#
+# Copyright (c) 2019, 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
+#
+##
+
+[Defines]
+  INF_VERSION                    = 0x0001001b
+  BASE_NAME                      = Timer
+  MODULE_UNI_FILE                = Timer.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"]
+  TimerExtra.uni
diff --git a/MdeModulePkg/Universal/TimerDxe/RiscV64/Timer.h b/MdeModulePkg/Universal/TimerDxe/RiscV64/Timer.h
new file mode 100644
index 000000000000..32f56f8fe1ca
--- /dev/null
+++ b/MdeModulePkg/Universal/TimerDxe/RiscV64/Timer.h
@@ -0,0 +1,174 @@
+/** @file
+  RISC-V Timer Architectural Protocol definitions
+
+  Copyright (c) 2019, 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
+
+**/
+
+#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/MdeModulePkg/Universal/TimerDxe/RiscV64/Timer.c b/MdeModulePkg/Universal/TimerDxe/RiscV64/Timer.c
new file mode 100644
index 000000000000..4deb91766d17
--- /dev/null
+++ b/MdeModulePkg/Universal/TimerDxe/RiscV64/Timer.c
@@ -0,0 +1,293 @@
+/** @file
+  RISC-V Timer Architectural Protocol
+
+  Copyright (c) 2019, 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 "Timer.h"
+#include <Library/RiscVSbiLib.h>
+#include <Register/RiscV64/RiscVAsm.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);
+  }
+  csr_clear(CSR_SIE, SIP_STIP); // Disable SMode timer int
+  csr_clear(CSR_SIP, SIP_STIP);
+  if (mTimerPeriod == 0) {
+    gBS->RestoreTPL (OriginalTPL);
+    csr_clear(CSR_SIE, SIP_STIP); // Disable SMode timer int
+    return;
+  }
+  RiscvTimer = csr_read(CSR_TIME);
+  SbiSetTimer (RiscvTimer += mTimerPeriod);
+  gBS->RestoreTPL (OriginalTPL);
+  csr_set(CSR_SIE, SIP_STIP); // 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;
+    csr_clear(CSR_SIE, SIP_STIP); // disable timer int
+    return EFI_SUCCESS;
+  }
+
+  mTimerPeriod = TimerPeriod / 10; // convert unit from 100ns to 1us
+  RiscvTimer = csr_read(CSR_TIME);
+  SbiSetTimer(RiscvTimer + mTimerPeriod);
+
+  mCpu->EnableInterrupt(mCpu);
+  csr_set(CSR_SIE, SIP_STIP); // enable 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/MdeModulePkg/Universal/TimerDxe/Timer.uni b/MdeModulePkg/Universal/TimerDxe/Timer.uni
new file mode 100644
index 000000000000..07272a8a787b
--- /dev/null
+++ b/MdeModulePkg/Universal/TimerDxe/Timer.uni
@@ -0,0 +1,15 @@
+// /** @file
+//
+// Timer Arch protocol strings.
+//
+// Copyright (c) 2016, 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
+//
+// **/
+
+
+#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/MdeModulePkg/Universal/TimerDxe/TimerExtra.uni b/MdeModulePkg/Universal/TimerDxe/TimerExtra.uni
new file mode 100644
index 000000000000..ad80afe2674c
--- /dev/null
+++ b/MdeModulePkg/Universal/TimerDxe/TimerExtra.uni
@@ -0,0 +1,13 @@
+// /** @file
+// Timer Localized Strings and Content
+//
+// Copyright (c) 2016, 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
+//
+// **/
+
+#string STR_PROPERTIES_MODULE_NAME
+#language en-US
+"Timer DXE Driver"
-- 
2.25.1