Add syscon peripheral

CMakeLists.txt

@@ -33,6 +33,7 @@ set(SRC_FILES_COMMON
   source/peripherals/plic.cpp
   source/peripherals/ram.cpp
   source/peripherals/virtio.cpp
+  source/peripherals/syscon.cpp
 
   source/instructions/loadinsn.cpp
   source/instructions/otherinsn.cpp

README.md

@@ -24,7 +24,8 @@ Welcome to the RV64GC Emulator repository, a RISC-V emulator project developed u
     - Raw framebuffer mode support: The firmware can write to memory-mapped locations to populate a framebuffer and display the contents on the screen.
 - PLIC
 - CLINT
-- VIRTIO
+- VIRTIO MMIO
+- SYSCON
 - bios (firmware), kernel and dtb loading
 - Successfully completes all [RISCV imafdcsu ISA tests](https://github.com/riscv-software-src/riscv-tests), with some caveats (see [Testing](#testing))
 

main.cpp

@@ -6,6 +6,7 @@
 #include "helper.hpp"
 #include "plic.hpp"
 #include "ram.hpp"
+#include "syscon.hpp"
 #include "virtio.hpp"
 #include <algorithm>
 #include <array>
@@ -171,8 +172,9 @@ int main(int argc, char* argv[])
 
     RamDevice dram = RamDevice(DRAM_BASE, ram_size_total, helper::load_file(bios_path));
     gpu::GpuDevice gpu = gpu::GpuDevice("RISC V emulator", font_path, 960, 540);
+    SysconDevice syscon = SysconDevice();
 
-    Cpu cpu = Cpu(&dram, &gpu, virtio_device);
+    Cpu cpu = Cpu(&dram, &gpu, virtio_device, &syscon);
 
     if (dtb_path)
     {

source/cpu.cpp

@@ -25,7 +25,7 @@
 #include <utility>
 
 Cpu::Cpu(RamDevice* dram_device, gpu::GpuDevice* gpu_device,
-         virtio::VirtioBlkDevice* virtio_blk_device)
+         virtio::VirtioBlkDevice* virtio_blk_device, SysconDevice* syscon_device)
     : mmu(*this)
 {
     mode = cpu::Mode::Machine;
@@ -57,9 +57,15 @@ Cpu::Cpu(RamDevice* dram_device, gpu::GpuDevice* gpu_device,
         bus.add_device(virtio_blk_device);
     }
 
+    if (syscon_device != nullptr)
+    {
+        bus.add_device(syscon_device);
+    }
+
     this->dram_device = dram_device;
     this->gpu_device = gpu_device;
     this->virtio_blk_device = virtio_blk_device;
+    this->syscon_device = syscon_device;
 
     csr::init_handler_array();
 }

source/include/cpu.hpp

@@ -10,6 +10,7 @@
 #include "mmu.hpp"
 #include "plic.hpp"
 #include "ram.hpp"
+#include "syscon.hpp"
 #include "virtio.hpp"
 #include <array>
 #include <iostream>
@@ -22,7 +23,8 @@ class Cpu
 {
   public:
     Cpu(RamDevice* dram_device, gpu::GpuDevice* gpu_device = nullptr,
-        virtio::VirtioBlkDevice* virtio_blk_device = nullptr);
+        virtio::VirtioBlkDevice* virtio_blk_device = nullptr,
+        SysconDevice* syscon_device = nullptr);
 
     void dump_registers(std::ostream& stream);
 
@@ -171,6 +173,7 @@ class Cpu
     RamDevice* dram_device;
     gpu::GpuDevice* gpu_device;
     virtio::VirtioBlkDevice* virtio_blk_device;
+    SysconDevice* syscon_device;
 
   public:
     cpu::Mode mode;

source/peripherals/include/syscon.hpp

@@ -0,0 +1,33 @@
+#pragma once
+
+#include "bus.hpp"
+#include <ostream>
+#include <string_view>
+
+class SysconDevice : public BusDevice
+{
+  public:
+    SysconDevice() = default;
+    virtual ~SysconDevice() = default;
+
+    uint64_t load(Bus& bus, uint64_t address, uint64_t length) override;
+    void store(Bus& bus, uint64_t address, uint64_t value, uint64_t length) override;
+
+  public:
+    uint64_t get_base_address() const override;
+    uint64_t get_end_address() const override;
+
+    void dump(std::ostream& stream) const override;
+    std::string_view get_peripheral_name() const override;
+
+  public:
+    static constexpr uint64_t poweroff_addr = 0x5555;
+
+    static constexpr uint64_t reboot_addr = 0x7777;
+
+    static constexpr uint64_t base_addr = poweroff_addr;
+
+    static constexpr uint64_t end_addr = reboot_addr;
+
+    static constexpr std::string_view peripheral_name = "SYSCON";
+};

source/peripherals/syscon.cpp

@@ -0,0 +1,38 @@
+#include "syscon.hpp"
+#include <cstdlib>
+
+uint64_t SysconDevice::load(Bus& bus, uint64_t address, uint64_t length)
+{
+    return 0;
+}
+
+void SysconDevice::store(Bus& bus, uint64_t address, uint64_t value, uint64_t length)
+{
+    if (value == poweroff_addr)
+    {
+        std::exit(0);
+    }
+    else if (value == reboot_addr)
+    {
+        std::exit(0);
+    }
+}
+
+void SysconDevice::dump(std::ostream& stream) const
+{
+}
+
+uint64_t SysconDevice::get_base_address() const
+{
+    return base_addr;
+}
+
+uint64_t SysconDevice::get_end_address() const
+{
+    return end_addr;
+}
+
+std::string_view SysconDevice::get_peripheral_name() const
+{
+    return peripheral_name;
+}