Rust Firmware with Bazel, SystemC, and QEMU

This repository demonstrates a modern Bazel-based build system for Rust firmware development with SystemC simulation and QEMU emulation support.

Features

• Bazel Build System: Modern, scalable build configuration
• Multi-target Support: ARM Cortex-M4 and RISC-V32 targets
• Rich Rust Ecosystem: Demonstrates use of embedded Rust crates
• SystemC Integration: Hardware modeling with SystemC/TLM
• QEMU Simulation: Full system emulation support
• Co-simulation: SystemC and QEMU integration

Project Structure

rust-firmware-bazel/
├── firmware/           # Rust firmware source
│   ├── src/
│   │   ├── main.rs    # Main firmware logic
│   │   ├── peripheral.rs  # Hardware abstraction
│   │   └── protocol.rs    # Communication protocol
│   ├── Cargo.toml     # Rust dependencies
│   └── BUILD.bazel    # Bazel build rules
├── systemc/           # SystemC models
│   ├── peripheral_model.h/cpp
│   ├── testbench.cpp
│   └── BUILD.bazel
├── qemu/              # QEMU configuration
│   ├── machine_config.c
│   ├── run_qemu.sh
│   └── BUILD.bazel
├── platforms/         # Target platform definitions
├── rust/              # Rust toolchain config
├── tools/             # Build and simulation scripts
├── WORKSPACE.bazel    # Bazel workspace
└── .bazelrc          # Bazel configuration

## Dependencies

- Bazel 6.0+
- Rust 1.75+
- SystemC 2.3.3+
- QEMU 7.0+
- ARM GCC toolchain (for debugging)
- RISC-V GCC toolchain (optional)

## Building

```bash
# Build all targets
./tools/build.sh

# Build specific target
bazel build //firmware:firmware --config=thumb
bazel build //firmware:firmware_riscv --config=riscv
bazel build //systemc:testbench

Running Simulations

# QEMU simulation (ARM)
./tools/simulate.sh qemu arm

# QEMU simulation (RISC-V)
./tools/simulate.sh qemu riscv

# SystemC simulation
./tools/simulate.sh systemc

# Co-simulation
./tools/simulate.sh co-sim

Debugging

# Debug ARM target
./tools/debug.sh arm

# Debug RISC-V target
./tools/debug.sh riscv

Rust Crates Used

• cortex-m & cortex-m-rt: ARM Cortex-M support
• riscv & riscv-rt: RISC-V support
• heapless: Static memory data structures
• nb: Non-blocking I/O traits
• embedded-hal: Hardware abstraction traits
• defmt: Efficient logging framework
• fugit: Time handling
• stm32f4xx-hal: STM32F4 HAL (optional)

Bazel Features Demonstrated

• Multi-platform builds with --platforms
• Crate universe for Rust dependencies
• Custom toolchain configuration
• Build configurations and feature flags
• Cross-compilation support

SystemC/TLM Features

• TLM 2.0 socket communication
• Interrupt modeling
• Register-based peripheral model
• Transaction-level modeling

Extending the Project

1. Add new peripherals: Create models in systemc/ and corresponding drivers in firmware/src/peripheral.rs
2. Add new targets: Define platforms in platforms/ and update WORKSPACE.bazel
3. Add dependencies: Update firmware/Cargo.toml and regenerate lock file
4. Custom QEMU machines: Extend qemu/machine_config.c