From f4b30dbdf6bd6be202e42908598cb54962542fe7 Mon Sep 17 00:00:00 2001
From: Nav <nav@navnav.me>
Date: Fri, 8 Dec 2023 23:04:04 +0000
Subject: [PATCH] Added `RiscVProgramInterface` for RISC-V debug tools that are
 unable to program RISC-V targets via the debug interface

---
 src/DebugToolDrivers/DebugTool.hpp            | 18 +++++++++++++++
 .../RiscV/RiscVProgramInterface.hpp           | 23 +++++++++++++++++++
 src/Targets/RiscV/RiscV.cpp                   |  5 ++++
 src/Targets/RiscV/RiscV.hpp                   |  2 ++
 4 files changed, 48 insertions(+)
 create mode 100644 src/DebugToolDrivers/TargetInterfaces/RiscV/RiscVProgramInterface.hpp

diff --git a/src/DebugToolDrivers/DebugTool.hpp b/src/DebugToolDrivers/DebugTool.hpp
index 221f7c39..cead69ee 100644
--- a/src/DebugToolDrivers/DebugTool.hpp
+++ b/src/DebugToolDrivers/DebugTool.hpp
@@ -9,6 +9,7 @@
 #include "src/Targets/Microchip/AVR/AVR8/TargetParameters.hpp"
 
 #include "TargetInterfaces/RiscV/RiscVDebugInterface.hpp"
+#include "TargetInterfaces/RiscV/RiscVProgramInterface.hpp"
 
 #include "src/Targets/TargetRegister.hpp"
 
@@ -113,6 +114,23 @@ public:
         return nullptr;
     }
 
+    /**
+     * Some debug tools are unable to program RISC-V targets via the RISC-V debug interface. Such tools must provide
+     * an implementation of the RiscVProgramInterface, which will allow them to implement flash memory writing as a
+     * separate function, independent of the debug interface.
+     *
+     * The RISC-V target driver will forward all flash memory writes to the RiscVProgramInterface returned by this
+     * member function. If nullptr is returned, the driver will fall back to the RiscVDebugInterface for flash memory
+     * writes.
+     *
+     * Note: the caller of this function will not manage the lifetime of the returned instance.
+     *
+     * @return
+     */
+    virtual DebugToolDrivers::TargetInterfaces::RiscV::RiscVProgramInterface* getRiscVProgramInterface() {
+        return nullptr;
+    }
+
     [[nodiscard]] bool isInitialised() const {
         return this->initialised;
     }
diff --git a/src/DebugToolDrivers/TargetInterfaces/RiscV/RiscVProgramInterface.hpp b/src/DebugToolDrivers/TargetInterfaces/RiscV/RiscVProgramInterface.hpp
new file mode 100644
index 00000000..976b52cd
--- /dev/null
+++ b/src/DebugToolDrivers/TargetInterfaces/RiscV/RiscVProgramInterface.hpp
@@ -0,0 +1,23 @@
+#pragma once
+
+#include <cstdint>
+
+#include "src/Targets/TargetMemory.hpp"
+
+namespace DebugToolDrivers::TargetInterfaces::RiscV
+{
+    class RiscVProgramInterface
+    {
+    public:
+        /**
+         * Should write to the target's FLASH memory.
+         *
+         * @param startAddress
+         * @param buffer
+         */
+        virtual void writeFlashMemory(
+            Targets::TargetMemoryAddress startAddress,
+            const Targets::TargetMemoryBuffer& buffer
+        ) = 0;
+    };
+}
diff --git a/src/Targets/RiscV/RiscV.cpp b/src/Targets/RiscV/RiscV.cpp
index c5b94c45..4d7c5856 100644
--- a/src/Targets/RiscV/RiscV.cpp
+++ b/src/Targets/RiscV/RiscV.cpp
@@ -51,6 +51,7 @@ namespace Targets::RiscV
 
     void RiscV::setDebugTool(DebugTool* debugTool) {
         this->riscVDebugInterface = debugTool->getRiscVDebugInterface();
+        this->riscVProgramInterface = debugTool->getRiscVProgramInterface();
     }
 
     void RiscV::activate() {
@@ -395,6 +396,10 @@ namespace Targets::RiscV
             return this->writeMemory(memoryType, alignedStartAddress, alignedBuffer);
         }
 
+        if (memoryType == TargetMemoryType::FLASH && this->riscVProgramInterface != nullptr) {
+            return this->riscVProgramInterface->writeFlashMemory(startAddress, buffer);
+        }
+
         this->riscVDebugInterface->writeDebugModuleRegister(RegisterAddress::ABSTRACT_DATA_1, startAddress);
 
         auto command = AbstractCommandRegister();
diff --git a/src/Targets/RiscV/RiscV.hpp b/src/Targets/RiscV/RiscV.hpp
index e4d34c16..5af469c7 100644
--- a/src/Targets/RiscV/RiscV.hpp
+++ b/src/Targets/RiscV/RiscV.hpp
@@ -8,6 +8,7 @@
 #include "src/DebugToolDrivers/DebugTool.hpp"
 
 #include "src/DebugToolDrivers/TargetInterfaces/RiscV/RiscVDebugInterface.hpp"
+#include "src/DebugToolDrivers/TargetInterfaces/RiscV/RiscVProgramInterface.hpp"
 
 #include "src/Targets/RiscV/RiscVGeneric.hpp"
 #include "src/Targets/RiscV/Registers/RegisterNumbers.hpp"
@@ -104,6 +105,7 @@ namespace Targets::RiscV
         RiscVRegisterDescriptor stackPointerRegisterDescriptor;
 
         DebugToolDrivers::TargetInterfaces::RiscV::RiscVDebugInterface* riscVDebugInterface = nullptr;
+        DebugToolDrivers::TargetInterfaces::RiscV::RiscVProgramInterface* riscVProgramInterface = nullptr;
 
         std::set<DebugModule::HartIndex> hartIndices;
         DebugModule::HartIndex selectedHartIndex = 0;