UefiPayloadPkg: Enable RiscV64 entry point to UPL

As per specification we are going to accept only one argument
at the entry point which is FDT pointer. Grab that and call
the entry point.

Signed-off-by: Dhaval Sharma <dhaval@rivosinc.com>

UefiPayloadPkg/UefiPayloadEntry/FitUniversalPayloadEntry.inf

@@ -38,6 +38,10 @@
   X64/VirtualMemory.c
   X64/DxeLoadFuncFit.c
 
+[Sources.RISCV64]
+  RiscV64/DxeLoadFunc.c
+  RiscV64/DxeLoadFuncFit.c
+
 [Packages]
   MdePkg/MdePkg.dec
   MdeModulePkg/MdeModulePkg.dec

UefiPayloadPkg/UefiPayloadEntry/RiscV64/DxeLoadFunc.c

@@ -0,0 +1,74 @@
+/** @file
+  RISC-V specific functionality for DxeLoad.
+
+  Copyright (c) 2020, Hewlett Packard Enterprise Development LP. All rights reserved.<BR>
+  Copyright (c) 2023, Rivos Inc
+
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+#include <PiPei.h>
+#include <Library/BaseLib.h>
+#include <Library/DebugLib.h>
+#include <Library/BaseMemoryLib.h>
+#include <Library/MemoryAllocationLib.h>
+#include <Library/PcdLib.h>
+#include <Library/HobLib.h>
+#include "UefiPayloadEntry.h"
+
+#define STACK_SIZE  0x20000
+
+/**
+   Transfers control to DxeCore.
+
+   This function performs a CPU architecture specific operations to execute
+   the entry point of DxeCore with the parameters of HobList.
+   It also installs EFI_END_OF_PEI_PPI to signal the end of PEI phase.
+
+   @param DxeCoreEntryPoint         The entry point of DxeCore.
+   @param HobList                   The start of HobList passed to DxeCore.
+
+**/
+VOID
+HandOffToDxeCore (
+  IN EFI_PHYSICAL_ADDRESS  DxeCoreEntryPoint,
+  IN EFI_PEI_HOB_POINTERS  HobList
+  )
+{
+  VOID  *BaseOfStack;
+  VOID  *TopOfStack;
+
+  //
+  //
+  // Allocate 128KB for the Stack
+  //
+  BaseOfStack = AllocatePages (EFI_SIZE_TO_PAGES (STACK_SIZE));
+  if (BaseOfStack == NULL) {
+    DEBUG ((DEBUG_ERROR, "%a: Can't allocate memory for stack.", __func__));
+    ASSERT (FALSE);
+  }
+
+  //
+  // Compute the top of the stack we were allocated. Pre-allocate a UINTN
+  // for safety.
+  //
+  TopOfStack = (VOID *)((UINTN)BaseOfStack + EFI_SIZE_TO_PAGES (STACK_SIZE) * EFI_PAGE_SIZE - CPU_STACK_ALIGNMENT);
+  TopOfStack = ALIGN_POINTER (TopOfStack, CPU_STACK_ALIGNMENT);
+
+  //
+  // Update the contents of BSP stack HOB to reflect the real stack info passed to DxeCore.
+  //
+  UpdateStackHob ((EFI_PHYSICAL_ADDRESS)(UINTN)BaseOfStack, STACK_SIZE);
+
+  DEBUG ((DEBUG_INFO, "DXE Core new stack at %x, stack pointer at %x\n", BaseOfStack, TopOfStack));
+
+  //
+  // Transfer the control to the entry point of DxeCore.
+  //
+  SwitchStack (
+    (SWITCH_STACK_ENTRY_POINT)(UINTN)DxeCoreEntryPoint,
+    HobList.Raw,
+    NULL,
+    TopOfStack
+    );
+}

UefiPayloadPkg/UefiPayloadEntry/RiscV64/DxeLoadFuncFit.c

@@ -0,0 +1,34 @@
+/** @file
+  x64-specifc functionality for DxeLoad.
+
+Copyright (c) 2006 - 2020, Intel Corporation. All rights reserved.<BR>
+SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#include <PiPei.h>
+#include <Library/BaseLib.h>
+#include <Library/DebugLib.h>
+#include <Library/BaseMemoryLib.h>
+#include <Library/MemoryAllocationLib.h>
+#include <Library/PcdLib.h>
+#include <Library/HobLib.h>
+#include <Library/FdtLib.h>
+#include <Library/PcdLib.h>
+#include "UefiPayloadEntry.h"
+
+/**
+  Entry point to the C language phase of UEFI payload.
+  @param[in]   Param1, Hartid which is ignored
+  @param[in]   Param2, Device Tree
+  @retval      It will not return if SUCCESS, and return error when passing bootloader parameter.
+**/
+EFI_STATUS
+EFIAPI
+_ModuleEntryPoint (
+  IN UINTN  Param1,
+  IN UINTN  Param2
+  )
+{
+  return FitUplEntryPoint (Param2);
+}