OSAL-RS

Operating System Abstraction Layer for Rust - A cross-platform compatibility layer for embedded and real-time systems development.

Overview

OSAL-RS provides a unified API for developing multi-platform embedded applications in Rust. It abstracts operating system-specific functionality, allowing you to write portable code that can run on different platforms with minimal changes.

Workspace Components

• osal-rs: Main Operating System Abstraction Layer with FreeRTOS support
• osal-rs-build: Build configuration tools and helpers
• osal-rs-porting: C FFI bridge layer for FreeRTOS integration
• osal-rs-tests: Comprehensive test suite for all components
• osal-rs-serde: ✨ Extensible serialization/deserialization framework with derive macros

Current Implementation Status

• ✅ FreeRTOS: Fully implemented and tested
• ✅ Serialization: Complete osal-rs-serde implementation with derive macros
• 🚧 POSIX: Planned for future releases
• 🚧 Other RTOSes: Under consideration

Features

Core OSAL Features

• Thread Management: Create, manage, and synchronize threads with priorities
• Synchronization Primitives: Mutexes (recursive & non-recursive), binary & counting semaphores, event groups
• Message Queues: Type-safe inter-thread communication with blocking/non-blocking operations
• Software Timers: Periodic and one-shot timers with callbacks
• Memory Allocation: Custom allocator integration for heap management
• Time Management: Duration handling and tick-based timing
• System Control: Scheduler control, task notifications, and system information
• No-std Support: Fully compatible with bare-metal embedded systems

🆕 osal-rs-serde Features

A complete serialization framework designed specifically for embedded systems:

• No-std Compatible: Works in bare-metal environments without standard library
• Zero-Copy: Direct buffer operations with no intermediate allocations
• Derive Macros: Automatic #[derive(Serialize, Deserialize)] implementation
• Rich Type Support: Primitives, arrays, tuples, Option, Vec, nested structs
• Extensible Architecture: Create custom serializers for any format (JSON, MessagePack, CBOR, etc.)
• Memory Efficient: Little-endian binary format with predictable sizes
• Compile-Time Guarantees: Type-safe serialization with static checks
• Standalone: Can be used independently in any Rust project

osal-rs-serde Quick Example

use osal_rs_serde::{Serialize, Deserialize, to_bytes, from_bytes};

#[derive(Serialize, Deserialize, Debug, PartialEq)]
struct SensorData {
    temperature: i16,
    humidity: u8,
    pressure: u32,
    status: Option<u8>,
}

let data = SensorData { 
    temperature: 25, 
    humidity: 60, 
    pressure: 1013,
    status: Some(0xFF),
};

// Serialize to stack buffer
let mut buffer = [0u8; 32];
let len = to_bytes(&data, &mut buffer).unwrap();

// Deserialize from buffer
let restored: SensorData = from_bytes(&buffer[..len]).unwrap();
assert_eq!(data, restored);

Integration with OSAL Queues

Perfect for inter-task communication:

use osal_rs::os::{Queue, QueueFn};
use osal_rs_serde::{Serialize, Deserialize, to_bytes, from_bytes};

#[derive(Serialize, Deserialize)]
struct Command {
    id: u32,
    params: [u16; 4],
}

fn sender_task(queue: &Queue) {
    let cmd = Command { id: 42, params: [1, 2, 3, 4] };
    let mut buffer = [0u8; 32];
    let len = to_bytes(&cmd, &mut buffer).unwrap();
    queue.post(&buffer[..len], 100).unwrap();
}

fn receiver_task(queue: &Queue) {
    let mut buffer = [0u8; 32];
    queue.fetch(&mut buffer, 100).unwrap();
    let cmd: Command = from_bytes(&buffer).unwrap();
}

For comprehensive documentation, examples, and advanced features, see:

• osal-rs-serde README - Complete feature documentation
• osal-rs-serde/derive README - Derive macro guide
• osal-rs-serde/examples/ - Working code examples

Prerequisites

Before using OSAL-RS in your project, ensure that:

1. FreeRTOS is properly configured in your project
2. FreeRTOS is linked to your final binary
3. C porting layer files from osal-rs-porting must be compiled and linked to your project
4. CMake build system is set up for your embedded project
5. Rust toolchain with appropriate target support is installed

Configuration

OSAL-RS requires proper FreeRTOS configuration. Ensure your FreeRTOSConfig.h includes:

#define configUSE_MUTEXES                1
#define configUSE_RECURSIVE_MUTEXES      1
#define configUSE_COUNTING_SEMAPHORES    1
#define configUSE_TIMERS                 1
#define configUSE_QUEUE_SETS             1
#define configSUPPORT_DYNAMIC_ALLOCATION 1

CMake Integration

OSAL-RS is designed to be integrated into CMake-based projects. Here are several integration examples:

Important: Always ensure that the C porting layer files from osal-rs-porting/freertos/ are compiled and linked to your project, as they provide the necessary FFI bridge between Rust and FreeRTOS.

Basic CMake Integration

Add OSAL-RS to your existing CMake project:

cmake_minimum_required(VERSION 3.20)
project(my_embedded_project C CXX)

# Configure FreeRTOS (assuming it's already in your project)
add_subdirectory(freertos)

# Add OSAL-RS porting layer
add_library(osal_rs_porting STATIC
    osal-rs-porting/freertos/src/osal_rs_freertos.c
)

target_include_directories(osal_rs_porting PUBLIC
    osal-rs-porting/freertos/inc
    ${FREERTOS_INCLUDE_DIRS}
)

target_link_libraries(osal_rs_porting PUBLIC
    freertos
)

# Configure Rust library
set(RUST_TARGET "thumbv7em-none-eabihf")  # Adjust for your target
set(OSAL_RS_LIB "${CMAKE_CURRENT_SOURCE_DIR}/osal-rs/target/${RUST_TARGET}/release/libosal_rs.a")

# Custom command to build Rust library
add_custom_command(
    OUTPUT ${OSAL_RS_LIB}
    COMMAND cargo build --release --target ${RUST_TARGET} --features freertos
    WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}/osal-rs
    COMMENT "Building OSAL-RS library"
)

add_custom_target(osal_rs_build DEPENDS ${OSAL_RS_LIB})

# Create imported library for OSAL-RS
add_library(osal_rs STATIC IMPORTED GLOBAL)
set_target_properties(osal_rs PROPERTIES
    IMPORTED_LOCATION ${OSAL_RS_LIB}
)
add_dependencies(osal_rs osal_rs_build)

# Your main application
add_executable(my_app
    src/main.c
)

target_link_libraries(my_app PRIVATE
    osal_rs
    osal_rs_porting
    freertos
)

Advanced CMake Integration with Multiple Configurations

# Function to build OSAL-RS for different configurations
function(add_osal_rs_library TARGET_NAME RUST_TARGET CARGO_PROFILE)
    set(PROFILE_DIR ${CARGO_PROFILE})
    if(CARGO_PROFILE STREQUAL "release")
        set(CARGO_FLAGS "--release")
    else()
        set(CARGO_FLAGS "")
    endif()

    set(LIB_PATH "${CMAKE_CURRENT_SOURCE_DIR}/osal-rs/target/${RUST_TARGET}/${PROFILE_DIR}/libosal_rs.a")

    add_custom_command(
        OUTPUT ${LIB_PATH}
        COMMAND cargo build ${CARGO_FLAGS} --target ${RUST_TARGET} --features freertos
        WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}/osal-rs
        COMMENT "Building OSAL-RS (${CARGO_PROFILE}) for ${RUST_TARGET}"
    )

    add_custom_target(${TARGET_NAME}_build DEPENDS ${LIB_PATH})

    add_library(${TARGET_NAME} STATIC IMPORTED GLOBAL)
    set_target_properties(${TARGET_NAME} PROPERTIES
        IMPORTED_LOCATION ${LIB_PATH}
    )
    add_dependencies(${TARGET_NAME} ${TARGET_NAME}_build)
endfunction()

# Use it in your project
add_osal_rs_library(osal_rs "thumbv7em-none-eabihf" "release")

Integration with Corrosion (Recommended)

For a more seamless Rust-CMake integration, use Corrosion:

cmake_minimum_required(VERSION 3.20)
project(my_embedded_project C CXX)

# Include Corrosion
include(FetchContent)
FetchContent_Declare(
    Corrosion
    GIT_REPOSITORY https://github.com/corrosion-rs/corrosion.git
    GIT_TAG v0.4
)
FetchContent_MakeAvailable(Corrosion)

# Import OSAL-RS crate
corrosion_import_crate(
    MANIFEST_PATH osal-rs/Cargo.toml
    FEATURES freertos
)

# Configure FreeRTOS
add_subdirectory(freertos)

# OSAL-RS porting layer
add_library(osal_rs_porting STATIC
    osal-rs-porting/freertos/src/osal_rs_freertos.c
)

target_include_directories(osal_rs_porting PUBLIC
    osal-rs-porting/freertos/inc
    ${FREERTOS_INCLUDE_DIRS}
)

target_link_libraries(osal_rs_porting PUBLIC
    freertos
)

# Your application
add_executable(my_app src/main.c)

target_link_libraries(my_app PRIVATE
    osal-rs
    osal_rs_porting
    freertos
)

Cross-Compilation Setup

Example CMake toolchain file for ARM Cortex-M:

# toolchain-arm-none-eabi.cmake
set(CMAKE_SYSTEM_NAME Generic)
set(CMAKE_SYSTEM_PROCESSOR arm)

set(CMAKE_C_COMPILER arm-none-eabi-gcc)
set(CMAKE_CXX_COMPILER arm-none-eabi-g++)
set(CMAKE_ASM_COMPILER arm-none-eabi-gcc)

set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)

# Rust target
set(RUST_TARGET "thumbv7em-none-eabihf")

Use it with:

cmake -DCMAKE_TOOLCHAIN_FILE=toolchain-arm-none-eabi.cmake -B build
cmake --build build

Custom FreeRTOS Configuration Path

By default, OSAL-RS looks for FreeRTOSConfig.h at <workspace_root>/inc/FreeRTOSConfig.h. You can override this path using the FREERTOS_CONFIG_PATH environment variable.

Setting via CMake

# Set custom path to FreeRTOSConfig.h
set(FREERTOS_CONFIG_PATH "${CMAKE_SOURCE_DIR}/inc/hhg-config/pico/FreeRTOSConfig.h")

# Pass to Cargo build via environment variable
add_custom_command(
    OUTPUT ${OSAL_RS_LIB}
    COMMAND ${CMAKE_COMMAND} -E env FREERTOS_CONFIG_PATH=${FREERTOS_CONFIG_PATH}
            cargo build --release --target ${RUST_TARGET} --features freertos
    WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}/osal-rs
    COMMENT "Building OSAL-RS library"
)

Setting via Environment Variable

# Set environment variable before building
export FREERTOS_CONFIG_PATH="/path/to/your/FreeRTOSConfig.h"
cargo build --release --target thumbv7em-none-eabihf --features freertos

Using with Corrosion

# Set environment variable for Corrosion
set(FREERTOS_CONFIG_PATH "${CMAKE_SOURCE_DIR}/inc/custom/FreeRTOSConfig.h")

corrosion_import_crate(
    MANIFEST_PATH osal-rs/Cargo.toml
    FEATURES freertos
)

# Set environment for the build
corrosion_set_env_vars(osal-rs
    FREERTOS_CONFIG_PATH=${FREERTOS_CONFIG_PATH}
)

Note: The build system will automatically regenerate Rust type bindings from the specified FreeRTOSConfig.h during the build process.

Usage Example

use osal_rs::os::*;

fn main() {
    // Create a thread
    let thread = Thread::new(
        "my_thread",
        4096,
        ThreadPriority::Normal,
        || {
            loop {
                println!("Hello from thread!");
                Duration::from_millis(1000).sleep();
            }
        }
    );

    // Create a mutex
    let mutex = Mutex::new().unwrap();
    
    // Use synchronization
    {
        let _guard = mutex.lock();
        // Critical section
    }

    // Create a queue
    let queue: Queue<u32> = Queue::new(10).unwrap();
    queue.send(42, Duration::from_millis(100)).unwrap();
    
    let value = queue.receive(Duration::from_millis(100)).unwrap();
    println!("Received: {}", value);
}

Building

For FreeRTOS targets:

# Install Rust target (example for ARM Cortex-M4F)
rustup target add thumbv7em-none-eabihf

# Build with FreeRTOS support
cargo build --release --target thumbv7em-none-eabihf --features freertos

For native development/testing:

# Build with POSIX support (when implemented)
cargo build --features posix,std

Cargo Features

OSAL-RS provides several Cargo features to customize the build configuration for different platforms and use cases:

Available Features

Feature Combinations

FreeRTOS Embedded Development (Default)

cargo build --target thumbv7em-none-eabihf --features freertos

FreeRTOS with Serialization Support

cargo build --target thumbv7em-none-eabihf --features freertos,serde

Native Development with Standard Library

cargo build --features posix,std

Native Development with Serialization

cargo build --features posix,std,serde

Using Features in Cargo.toml

To use OSAL-RS in your project with specific features:

[dependencies]
osal-rs = { version = "0.3", features = ["freertos"] }

# Or with serialization support
osal-rs = { version = "0.3", features = ["freertos", "serde"] }

Project Structure

osal-rs/
├── osal-rs/              # Main library crate
├── osal-rs-build/        # Build utilities
├── osal-rs-tests/        # Test suite
└── osal-rs-porting/      # Platform-specific C/C++ code
    └── freertos/         # FreeRTOS porting layer
        ├── inc/          # Header files
        └── src/          # Implementation

License

This project is licensed under the GPL-3.0 License - see the LICENSE file for details.

Contributing

Contributions are welcome! Please feel free to submit pull requests or open issues for bugs and feature requests.

Author

Antonio Salsi

Repository

https://github.com/HiHappyGarden/osal-rs

Example implementation

https://github.com/HiHappyGarden/hi-happy-garden-rs