[RFC PATCH V2 16/19] UefiCpuPkg/CpuDxe: Add RISC-V support in CpuDxe module

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

This DXE module initializes the RISC-V CPU by installing
the CPU specific ARCH protocol handlers. This also initializes
the RISCV_EFI_BOOT_PROTOCOL which is required on RISC-V
platforms.

Signed-off-by: Sunil V L <sunilvl@ventanamicro.com>
---
 UefiCpuPkg/CpuDxe/CpuDxe.inf       |  16 +-
 UefiCpuPkg/CpuDxe/RiscV64/CpuDxe.h | 200 ++++++++++++
 UefiCpuPkg/CpuDxe/RiscV64/CpuDxe.c | 337 ++++++++++++++++++++
 3 files changed, 552 insertions(+), 1 deletion(-)

diff --git a/UefiCpuPkg/CpuDxe/CpuDxe.inf b/UefiCpuPkg/CpuDxe/CpuDxe.inf
index 4f2ea42f1612..17cf2b1ecd30 100644
--- a/UefiCpuPkg/CpuDxe/CpuDxe.inf
+++ b/UefiCpuPkg/CpuDxe/CpuDxe.inf
@@ -1,8 +1,12 @@
 ## @file
-#  CPU driver installs CPU Architecture Protocol and CPU MP protocol.
+#  On X86, CPU driver installs CPU Architecture Protocol and CPU MP protocol.
+#
+#  On RISC-V, CPU driver installs CPU Architecture Protocol and RISC-V boot
+#  protocol
 #
 #  Copyright (c) 2008 - 2019, Intel Corporation. All rights reserved.<BR>
 #  Copyright (c) 2017, AMD Incorporated. All rights reserved.<BR>
+#  Copyright (c) 2022, Ventana Micro Systems Inc. All rights reserved.<BR>
 #
 #  SPDX-License-Identifier: BSD-2-Clause-Patent
 #
@@ -44,6 +48,9 @@ [LibraryClasses.IA32, LibraryClasses.X64]
   MtrrLib
   UefiCpuLib
 
+[LibraryClasses.RISCV64]
+  RiscVSbiLib
+
 [Sources.IA32, Sources.X64]
   CpuDxe.c
   CpuDxe.h
@@ -62,11 +69,18 @@ [Sources.X64]
   X64/CpuAsm.nasm
   X64/PagingAttribute.c
 
+[Sources.RISCV64]
+  RiscV64/CpuDxe.c
+  RiscV64/CpuDxe.h
+
 [Protocols]
   gEfiCpuArchProtocolGuid                       ## PRODUCES
   gEfiMpServiceProtocolGuid                     ## PRODUCES
   gEfiSmmBase2ProtocolGuid                      ## SOMETIMES_CONSUMES
 
+[Protocols.RISCV64]
+  gRiscVEfiBootProtocolGuid                     ## PRODUCES
+
 [Guids]
   gIdleLoopEventGuid                            ## CONSUMES           ## Event
   gEfiVectorHandoffTableGuid                    ## SOMETIMES_CONSUMES ## SystemTable
diff --git a/UefiCpuPkg/CpuDxe/RiscV64/CpuDxe.h b/UefiCpuPkg/CpuDxe/RiscV64/CpuDxe.h
new file mode 100644
index 000000000000..f039759dbdaa
--- /dev/null
+++ b/UefiCpuPkg/CpuDxe/RiscV64/CpuDxe.h
@@ -0,0 +1,200 @@
+/** @file
+  RISC-V CPU DXE module header file.
+
+  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
+
+**/
+
+#ifndef CPU_DXE_H_
+#define CPU_DXE_H_
+
+#include <PiDxe.h>
+
+#include <Protocol/Cpu.h>
+#include <Protocol/RiscVBootProtocol.h>
+#include <Library/RiscVSbiLib.h>
+#include <Library/BaseLib.h>
+#include <Library/CpuExceptionHandlerLib.h>
+#include <Library/DebugLib.h>
+#include <Library/UefiBootServicesTableLib.h>
+#include <Library/UefiDriverEntryPoint.h>
+
+/**
+  Flush CPU data cache. If the instruction cache is fully coherent
+  with all DMA operations then function can just return EFI_SUCCESS.
+
+  @param  This              Protocol instance structure
+  @param  Start             Physical address to start flushing from.
+  @param  Length            Number of bytes to flush. Round up to chipset
+                            granularity.
+  @param  FlushType         Specifies the type of flush operation to perform.
+
+  @retval EFI_SUCCESS       If cache was flushed
+  @retval EFI_UNSUPPORTED   If flush type is not supported.
+  @retval EFI_DEVICE_ERROR  If requested range could not be flushed.
+
+**/
+EFI_STATUS
+EFIAPI
+CpuFlushCpuDataCache (
+  IN EFI_CPU_ARCH_PROTOCOL  *This,
+  IN EFI_PHYSICAL_ADDRESS   Start,
+  IN UINT64                 Length,
+  IN EFI_CPU_FLUSH_TYPE     FlushType
+  );
+
+/**
+  Enables CPU interrupts.
+
+  @param  This              Protocol instance structure
+
+  @retval EFI_SUCCESS       If interrupts were enabled in the CPU
+  @retval EFI_DEVICE_ERROR  If interrupts could not be enabled on the CPU.
+
+**/
+EFI_STATUS
+EFIAPI
+CpuEnableInterrupt (
+  IN EFI_CPU_ARCH_PROTOCOL  *This
+  );
+
+/**
+  Disables CPU interrupts.
+
+  @param  This              Protocol instance structure
+
+  @retval EFI_SUCCESS       If interrupts were disabled in the CPU.
+  @retval EFI_DEVICE_ERROR  If interrupts could not be disabled on the CPU.
+
+**/
+EFI_STATUS
+EFIAPI
+CpuDisableInterrupt (
+  IN EFI_CPU_ARCH_PROTOCOL  *This
+  );
+
+/**
+  Return the state of interrupts.
+
+  @param  This                   Protocol instance structure
+  @param  State                  Pointer to the CPU's current interrupt state
+
+  @retval EFI_SUCCESS            If interrupts were disabled in the CPU.
+  @retval EFI_INVALID_PARAMETER  State is NULL.
+
+**/
+EFI_STATUS
+EFIAPI
+CpuGetInterruptState (
+  IN  EFI_CPU_ARCH_PROTOCOL  *This,
+  OUT BOOLEAN                *State
+  );
+
+/**
+  Generates an INIT to the CPU.
+
+  @param  This              Protocol instance structure
+  @param  InitType          Type of CPU INIT to perform
+
+  @retval EFI_SUCCESS       If CPU INIT occurred. This value should never be
+                            seen.
+  @retval EFI_DEVICE_ERROR  If CPU INIT failed.
+  @retval EFI_UNSUPPORTED   Requested type of CPU INIT not supported.
+
+**/
+EFI_STATUS
+EFIAPI
+CpuInit (
+  IN EFI_CPU_ARCH_PROTOCOL  *This,
+  IN EFI_CPU_INIT_TYPE      InitType
+  );
+
+/**
+  Registers a function to be called from the CPU interrupt handler.
+
+  @param  This                   Protocol instance structure
+  @param  InterruptType          Defines which interrupt to hook. IA-32
+                                 valid range is 0x00 through 0xFF
+  @param  InterruptHandler       A pointer to a function of type
+                                 EFI_CPU_INTERRUPT_HANDLER that is called
+                                 when a processor interrupt occurs.  A null
+                                 pointer is an error condition.
+
+  @retval EFI_SUCCESS            If handler installed or uninstalled.
+  @retval EFI_ALREADY_STARTED    InterruptHandler is not NULL, and a handler
+                                 for InterruptType was previously installed.
+  @retval EFI_INVALID_PARAMETER  InterruptHandler is NULL, and a handler for
+                                 InterruptType was not previously installed.
+  @retval EFI_UNSUPPORTED        The interrupt specified by InterruptType
+                                 is not supported.
+
+**/
+EFI_STATUS
+EFIAPI
+CpuRegisterInterruptHandler (
+  IN EFI_CPU_ARCH_PROTOCOL      *This,
+  IN EFI_EXCEPTION_TYPE         InterruptType,
+  IN EFI_CPU_INTERRUPT_HANDLER  InterruptHandler
+  );
+
+/**
+  Returns a timer value from one of the CPU's internal timers. There is no
+  inherent time interval between ticks but is a function of the CPU frequency.
+
+  @param  This                - Protocol instance structure.
+  @param  TimerIndex          - Specifies which CPU timer is requested.
+  @param  TimerValue          - Pointer to the returned timer value.
+  @param  TimerPeriod         - A pointer to the amount of time that passes
+                                in femtoseconds (10-15) for each increment
+                                of TimerValue. If TimerValue does not
+                                increment at a predictable rate, then 0 is
+                                returned.  The amount of time that has
+                                passed between two calls to GetTimerValue()
+                                can be calculated with the formula
+                                (TimerValue2 - TimerValue1) * TimerPeriod.
+                                This parameter is optional and may be NULL.
+
+  @retval EFI_SUCCESS           - If the CPU timer count was returned.
+  @retval EFI_UNSUPPORTED       - If the CPU does not have any readable timers.
+  @retval EFI_DEVICE_ERROR      - If an error occurred while reading the timer.
+  @retval EFI_INVALID_PARAMETER - TimerIndex is not valid or TimerValue is NULL.
+
+**/
+EFI_STATUS
+EFIAPI
+CpuGetTimerValue (
+  IN  EFI_CPU_ARCH_PROTOCOL  *This,
+  IN  UINT32                 TimerIndex,
+  OUT UINT64                 *TimerValue,
+  OUT UINT64                 *TimerPeriod OPTIONAL
+  );
+
+/**
+  Set memory cacheability attributes for given range of memeory.
+
+  @param  This                   Protocol instance structure
+  @param  BaseAddress            Specifies the start address of the
+                                 memory range
+  @param  Length                 Specifies the length of the memory range
+  @param  Attributes             The memory cacheability for the memory range
+
+  @retval EFI_SUCCESS            If the cacheability of that memory range is
+                                 set successfully
+  @retval EFI_UNSUPPORTED        If the desired operation cannot be done
+  @retval EFI_INVALID_PARAMETER  The input parameter is not correct,
+                                 such as Length = 0
+
+**/
+EFI_STATUS
+EFIAPI
+CpuSetMemoryAttributes (
+  IN EFI_CPU_ARCH_PROTOCOL  *This,
+  IN EFI_PHYSICAL_ADDRESS   BaseAddress,
+  IN UINT64                 Length,
+  IN UINT64                 Attributes
+  );
+
+#endif
diff --git a/UefiCpuPkg/CpuDxe/RiscV64/CpuDxe.c b/UefiCpuPkg/CpuDxe/RiscV64/CpuDxe.c
new file mode 100644
index 000000000000..4112b6b8c6b9
--- /dev/null
+++ b/UefiCpuPkg/CpuDxe/RiscV64/CpuDxe.c
@@ -0,0 +1,337 @@
+/** @file
+  RISC-V CPU DXE driver.
+
+  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 <Library/PcdLib.h>
+#include <Register/RiscV64/RiscVAsm.h>
+#include "CpuDxe.h"
+
+//
+// Global Variables
+//
+STATIC BOOLEAN     mInterruptState = FALSE;
+STATIC EFI_HANDLE  mCpuHandle      = NULL;
+STATIC UINTN mBootHartId;
+RISCV_EFI_BOOT_PROTOCOL gRiscvBootProtocol;
+
+EFI_STATUS
+EFIAPI
+RiscvGetBootHartId (
+  IN RISCV_EFI_BOOT_PROTOCOL   *This,
+  OUT UINTN                    *BootHartId
+  )
+{
+  if((This != &gRiscvBootProtocol) || (BootHartId == NULL)) {
+    return EFI_INVALID_PARAMETER;
+  }
+
+  *BootHartId = mBootHartId;
+  return EFI_SUCCESS;
+}
+
+RISCV_EFI_BOOT_PROTOCOL  gRiscvBootProtocol = {
+  RISCV_EFI_BOOT_PROTOCOL_LATEST_VERSION,
+  RiscvGetBootHartId
+};
+
+EFI_CPU_ARCH_PROTOCOL  gCpu = {
+  CpuFlushCpuDataCache,
+  CpuEnableInterrupt,
+  CpuDisableInterrupt,
+  CpuGetInterruptState,
+  CpuInit,
+  CpuRegisterInterruptHandler,
+  CpuGetTimerValue,
+  CpuSetMemoryAttributes,
+  1,                          // NumberOfTimers
+  4                           // DmaBufferAlignment
+};
+
+//
+// CPU Arch Protocol Functions
+//
+
+/**
+  Flush CPU data cache. If the instruction cache is fully coherent
+  with all DMA operations then function can just return EFI_SUCCESS.
+
+  @param  This              Protocol instance structure
+  @param  Start             Physical address to start flushing from.
+  @param  Length            Number of bytes to flush. Round up to chipset
+                            granularity.
+  @param  FlushType         Specifies the type of flush operation to perform.
+
+  @retval EFI_SUCCESS       If cache was flushed
+  @retval EFI_UNSUPPORTED   If flush type is not supported.
+  @retval EFI_DEVICE_ERROR  If requested range could not be flushed.
+
+**/
+EFI_STATUS
+EFIAPI
+CpuFlushCpuDataCache (
+  IN EFI_CPU_ARCH_PROTOCOL  *This,
+  IN EFI_PHYSICAL_ADDRESS   Start,
+  IN UINT64                 Length,
+  IN EFI_CPU_FLUSH_TYPE     FlushType
+  )
+{
+  return EFI_SUCCESS;
+}
+
+/**
+  Enables CPU interrupts.
+
+  @param  This              Protocol instance structure
+
+  @retval EFI_SUCCESS       If interrupts were enabled in the CPU
+  @retval EFI_DEVICE_ERROR  If interrupts could not be enabled on the CPU.
+
+**/
+EFI_STATUS
+EFIAPI
+CpuEnableInterrupt (
+  IN EFI_CPU_ARCH_PROTOCOL  *This
+  )
+{
+  EnableInterrupts ();
+  mInterruptState = TRUE;
+  return EFI_SUCCESS;
+}
+
+/**
+  Disables CPU interrupts.
+
+  @param  This              Protocol instance structure
+
+  @retval EFI_SUCCESS       If interrupts were disabled in the CPU.
+  @retval EFI_DEVICE_ERROR  If interrupts could not be disabled on the CPU.
+
+**/
+EFI_STATUS
+EFIAPI
+CpuDisableInterrupt (
+  IN EFI_CPU_ARCH_PROTOCOL  *This
+  )
+{
+  DisableInterrupts ();
+  mInterruptState = FALSE;
+  return EFI_SUCCESS;
+}
+
+/**
+  Return the state of interrupts.
+
+  @param  This                   Protocol instance structure
+  @param  State                  Pointer to the CPU's current interrupt state
+
+  @retval EFI_SUCCESS            If interrupts were disabled in the CPU.
+  @retval EFI_INVALID_PARAMETER  State is NULL.
+
+**/
+EFI_STATUS
+EFIAPI
+CpuGetInterruptState (
+  IN  EFI_CPU_ARCH_PROTOCOL  *This,
+  OUT BOOLEAN                *State
+  )
+{
+  if (State == NULL) {
+    return EFI_INVALID_PARAMETER;
+  }
+
+  *State = mInterruptState;
+  return EFI_SUCCESS;
+}
+
+/**
+  Generates an INIT to the CPU.
+
+  @param  This              Protocol instance structure
+  @param  InitType          Type of CPU INIT to perform
+
+  @retval EFI_SUCCESS       If CPU INIT occurred. This value should never be
+                            seen.
+  @retval EFI_DEVICE_ERROR  If CPU INIT failed.
+  @retval EFI_UNSUPPORTED   Requested type of CPU INIT not supported.
+
+**/
+EFI_STATUS
+EFIAPI
+CpuInit (
+  IN EFI_CPU_ARCH_PROTOCOL  *This,
+  IN EFI_CPU_INIT_TYPE      InitType
+  )
+{
+  return EFI_UNSUPPORTED;
+}
+
+/**
+  Registers a function to be called from the CPU interrupt handler.
+
+  @param  This                   Protocol instance structure
+  @param  InterruptType          Defines which interrupt to hook. IA-32
+                                 valid range is 0x00 through 0xFF
+  @param  InterruptHandler       A pointer to a function of type
+                                 EFI_CPU_INTERRUPT_HANDLER that is called
+                                 when a processor interrupt occurs.  A null
+                                 pointer is an error condition.
+
+  @retval EFI_SUCCESS            If handler installed or uninstalled.
+  @retval EFI_ALREADY_STARTED    InterruptHandler is not NULL, and a handler
+                                 for InterruptType was previously installed.
+  @retval EFI_INVALID_PARAMETER  InterruptHandler is NULL, and a handler for
+                                 InterruptType was not previously installed.
+  @retval EFI_UNSUPPORTED        The interrupt specified by InterruptType
+                                 is not supported.
+
+**/
+EFI_STATUS
+EFIAPI
+CpuRegisterInterruptHandler (
+  IN EFI_CPU_ARCH_PROTOCOL      *This,
+  IN EFI_EXCEPTION_TYPE         InterruptType,
+  IN EFI_CPU_INTERRUPT_HANDLER  InterruptHandler
+  )
+{
+  return RegisterCpuInterruptHandler (InterruptType, InterruptHandler);
+}
+
+/**
+  Returns a timer value from one of the CPU's internal timers. There is no
+  inherent time interval between ticks but is a function of the CPU frequency.
+
+  @param  This                - Protocol instance structure.
+  @param  TimerIndex          - Specifies which CPU timer is requested.
+  @param  TimerValue          - Pointer to the returned timer value.
+  @param  TimerPeriod         - A pointer to the amount of time that passes
+                                in femtoseconds (10-15) for each increment
+                                of TimerValue. If TimerValue does not
+                                increment at a predictable rate, then 0 is
+                                returned.  The amount of time that has
+                                passed between two calls to GetTimerValue()
+                                can be calculated with the formula
+                                (TimerValue2 - TimerValue1) * TimerPeriod.
+                                This parameter is optional and may be NULL.
+
+  @retval EFI_SUCCESS           - If the CPU timer count was returned.
+  @retval EFI_UNSUPPORTED       - If the CPU does not have any readable timers.
+  @retval EFI_DEVICE_ERROR      - If an error occurred while reading the timer.
+  @retval EFI_INVALID_PARAMETER - TimerIndex is not valid or TimerValue is NULL.
+
+**/
+EFI_STATUS
+EFIAPI
+CpuGetTimerValue (
+  IN  EFI_CPU_ARCH_PROTOCOL  *This,
+  IN  UINT32                 TimerIndex,
+  OUT UINT64                 *TimerValue,
+  OUT UINT64                 *TimerPeriod OPTIONAL
+  )
+{
+  return EFI_UNSUPPORTED;
+}
+
+/**
+  Implementation of SetMemoryAttributes() service of CPU Architecture Protocol.
+
+  This function modifies the attributes for the memory region specified by BaseAddress and
+  Length from their current attributes to the attributes specified by Attributes.
+
+  @param  This             The EFI_CPU_ARCH_PROTOCOL instance.
+  @param  BaseAddress      The physical address that is the start address of a memory region.
+  @param  Length           The size in bytes of the memory region.
+  @param  Attributes       The bit mask of attributes to set for the memory region.
+
+  @retval EFI_SUCCESS           The attributes were set for the memory region.
+  @retval EFI_ACCESS_DENIED     The attributes for the memory resource range specified by
+                                BaseAddress and Length cannot be modified.
+  @retval EFI_INVALID_PARAMETER Length is zero.
+                                Attributes specified an illegal combination of attributes that
+                                cannot be set together.
+  @retval EFI_OUT_OF_RESOURCES  There are not enough system resources to modify the attributes of
+                                the memory resource range.
+  @retval EFI_UNSUPPORTED       The processor does not support one or more bytes of the memory
+                                resource range specified by BaseAddress and Length.
+                                The bit mask of attributes is not support for the memory resource
+                                range specified by BaseAddress and Length.
+
+**/
+EFI_STATUS
+EFIAPI
+CpuSetMemoryAttributes (
+  IN EFI_CPU_ARCH_PROTOCOL  *This,
+  IN EFI_PHYSICAL_ADDRESS   BaseAddress,
+  IN UINT64                 Length,
+  IN UINT64                 Attributes
+  )
+{
+  DEBUG ((DEBUG_INFO, "%a: Set memory attributes not supported yet\n", __FUNCTION__));
+  return EFI_SUCCESS;
+}
+
+/**
+  Initialize the state information for the CPU Architectural Protocol.
+
+  @param ImageHandle     Image handle this driver.
+  @param SystemTable     Pointer to the System Table.
+
+  @retval EFI_SUCCESS           Thread can be successfully created
+  @retval EFI_OUT_OF_RESOURCES  Cannot allocate protocol data structure
+  @retval EFI_DEVICE_ERROR      Cannot create the thread
+
+**/
+EFI_STATUS
+EFIAPI
+InitializeCpu (
+  IN EFI_HANDLE        ImageHandle,
+  IN EFI_SYSTEM_TABLE  *SystemTable
+  )
+{
+  EFI_STATUS  Status;
+  EFI_RISCV_FIRMWARE_CONTEXT *FirmwareContext;
+
+  GetFirmwareContextPointer (&FirmwareContext);
+  ASSERT (FirmwareContext != NULL);
+  if (FirmwareContext == NULL) {
+    DEBUG ((DEBUG_ERROR, "Failed to get the pointer of EFI_RISCV_FIRMWARE_CONTEXT\n"));
+    return EFI_NOT_FOUND;
+  }
+  DEBUG ((DEBUG_INFO, " %a: Firmware Context is at 0x%x.\n", __FUNCTION__, FirmwareContext));
+
+  mBootHartId = FirmwareContext->BootHartId;
+  DEBUG ((DEBUG_INFO, " %a: mBootHartId = 0x%x.\n", __FUNCTION__, mBootHartId));
+
+
+  InitializeCpuExceptionHandlers(NULL);
+
+  //
+  // Make sure interrupts are disabled
+  //
+  DisableInterrupts ();
+
+  Status = gBS->InstallProtocolInterface (&ImageHandle,
+                                          &gRiscVEfiBootProtocolGuid,
+                                          EFI_NATIVE_INTERFACE,
+                                          &gRiscvBootProtocol
+                                         );
+
+  ASSERT_EFI_ERROR (Status);
+
+  //
+  // Install CPU Architectural Protocol
+  //
+  Status = gBS->InstallMultipleProtocolInterfaces (
+                  &mCpuHandle,
+                  &gEfiCpuArchProtocolGuid,
+                  &gCpu,
+                  NULL
+                  );
+  ASSERT_EFI_ERROR (Status);
+  return Status;
+}
-- 
2.25.1