Device Driver Architecture

VeridianOS implements a user-space driver model that prioritizes isolation, security, and fault tolerance while maintaining high performance through capability-based hardware access and zero-copy communication.

Design Philosophy

Core Principles

User-Space Isolation: All device drivers run in separate user-space processes
Capability-Based Access: Hardware resources accessed only through unforgeable capabilities
Fault Tolerance: Driver crashes don't bring down the entire system
Hot-Pluggable: Drivers can be loaded, unloaded, and restarted dynamically
Performance: Zero-copy DMA and efficient interrupt handling

Benefits over Kernel Drivers

Aspect	User-Space Drivers	Kernel Drivers
Fault Isolation	Driver crash isolated	System-wide failure
Security	Capability-controlled access	Full kernel privileges
Debugging	Standard debugging tools	Kernel debugging required
Development	User-space comfort	Kernel constraints
Memory Protection	Full MMU protection	No protection
Hot-Plug	Dynamic load/unload	Static or complex

Driver Framework

Driver Trait

All drivers implement a common interface:

#![allow(unused)]
fn main() {
#[async_trait]
pub trait Driver: Send + Sync {
    /// Initialize driver with hardware capabilities
    async fn init(&mut self, capabilities: HardwareCapabilities) -> Result<(), DriverError>;
    
    /// Start driver operation
    async fn start(&mut self) -> Result<(), DriverError>;
    
    /// Handle hardware interrupt
    async fn handle_interrupt(&self, vector: u32) -> Result<(), DriverError>;
    
    /// Handle device hotplug event
    async fn hotplug(&self, event: HotplugEvent) -> Result<(), DriverError>;
    
    /// Shutdown driver gracefully
    async fn shutdown(&mut self) -> Result<(), DriverError>;
    
    /// Get driver metadata
    fn metadata(&self) -> DriverMetadata;
}

pub struct DriverMetadata {
    pub name: String,
    pub version: Version,
    pub vendor_id: Option<u16>,
    pub device_id: Option<u16>,
    pub device_class: DeviceClass,
    pub capabilities_required: Vec<CapabilityType>,
}
}

Hardware Capabilities

Access to hardware resources is granted through capabilities:

#![allow(unused)]
fn main() {
pub struct HardwareCapabilities {
    /// Memory-mapped I/O regions
    pub mmio_regions: Vec<MmioRegion>,
    
    /// Interrupt lines
    pub interrupts: Vec<InterruptLine>,
    
    /// DMA capability for memory transfers
    pub dma_capability: Option<DmaCapability>,
    
    /// PCI configuration space access
    pub pci_config: Option<PciConfigCapability>,
    
    /// I/O port access (x86_64 only)
    #[cfg(target_arch = "x86_64")]
    pub io_ports: Vec<IoPortRange>,
}

pub struct MmioRegion {
    /// Physical base address
    pub base_addr: PhysAddr,
    
    /// Region size in bytes
    pub size: usize,
    
    /// Access permissions
    pub permissions: MmioPermissions,
    
    /// Cache policy
    pub cache_policy: CachePolicy,
}

#[derive(Debug, Clone, Copy)]
pub struct MmioPermissions {
    pub read: bool,
    pub write: bool,
    pub execute: bool,
}

#[derive(Debug, Clone, Copy)]
pub enum CachePolicy {
    /// Cacheable, write-back
    WriteBack,
    
    /// Cacheable, write-through
    WriteThrough,
    
    /// Uncacheable
    Uncached,
    
    /// Write-combining (for framebuffers)
    WriteCombining,
}
}

Hardware Abstraction Layer

Register Access

Safe register access through memory-mapped I/O:

#![allow(unused)]
fn main() {
pub struct RegisterBlock<T> {
    base: VirtAddr,
    _phantom: PhantomData<T>,
}

impl<T> RegisterBlock<T> {
    /// Create new register block from capability
    pub fn new(mmio_cap: MmioCapability) -> Result<Self, DriverError> {
        let base = map_mmio_region(mmio_cap)?;
        Ok(Self {
            base,
            _phantom: PhantomData,
        })
    }
    
    /// Read 32-bit register
    pub fn read32(&self, offset: usize) -> u32 {
        unsafe {
            let addr = self.base.as_ptr::<u32>().add(offset / 4);
            core::ptr::read_volatile(addr)
        }
    }
    
    /// Write 32-bit register
    pub fn write32(&self, offset: usize, value: u32) {
        unsafe {
            let addr = self.base.as_ptr::<u32>().add(offset / 4);
            core::ptr::write_volatile(addr, value);
        }
    }
    
    /// Atomic read-modify-write
    pub fn modify32<F>(&self, offset: usize, f: F) 
    where
        F: FnOnce(u32) -> u32,
    {
        let old = self.read32(offset);
        let new = f(old);
        self.write32(offset, new);
    }
}

// Type-safe register definitions
#[repr(C)]
pub struct NetworkControllerRegs {
    pub control: RW<u32>,       // Offset 0x00
    pub status: RO<u32>,        // Offset 0x04
    pub interrupt_mask: RW<u32>, // Offset 0x08
    pub dma_addr: RW<u64>,      // Offset 0x0C
    _reserved: [u8; 240],
}

// Register field access
impl NetworkControllerRegs {
    pub fn enable(&mut self) {
        self.control.modify(|val| val | CONTROL_ENABLE);
    }
    
    pub fn is_link_up(&self) -> bool {
        self.status.read() & STATUS_LINK_UP != 0
    }
}
}

DMA Operations

Zero-copy DMA for high-performance data transfer:

#![allow(unused)]
fn main() {
pub struct DmaBuffer {
    /// Virtual address for CPU access
    pub virt_addr: VirtAddr,
    
    /// Physical address for device access
    pub phys_addr: PhysAddr,
    
    /// Buffer size
    pub size: usize,
    
    /// DMA direction
    pub direction: DmaDirection,
}

#[derive(Debug, Clone, Copy)]
pub enum DmaDirection {
    /// Device to memory
    FromDevice,
    
    /// Memory to device
    ToDevice,
    
    /// Bidirectional
    Bidirectional,
}

impl DmaBuffer {
    /// Allocate DMA buffer
    pub fn allocate(
        size: usize,
        direction: DmaDirection,
        dma_cap: &DmaCapability,
    ) -> Result<Self, DriverError> {
        let layout = Layout::from_size_align(size, PAGE_SIZE)?;
        
        // Allocate physically contiguous memory
        let phys_addr = allocate_dma_memory(layout, dma_cap)?;
        
        // Map into driver's address space
        let virt_addr = map_dma_buffer(phys_addr, size, direction)?;
        
        Ok(Self {
            virt_addr,
            phys_addr,
            size,
            direction,
        })
    }
    
    /// Sync buffer for CPU access
    pub fn sync_for_cpu(&self) -> Result<(), DriverError> {
        match self.direction {
            DmaDirection::FromDevice | DmaDirection::Bidirectional => {
                invalidate_cache_range(self.virt_addr, self.size);
            }
            _ => {}
        }
        Ok(())
    }
    
    /// Sync buffer for device access
    pub fn sync_for_device(&self) -> Result<(), DriverError> {
        match self.direction {
            DmaDirection::ToDevice | DmaDirection::Bidirectional => {
                flush_cache_range(self.virt_addr, self.size);
            }
            _ => {}
        }
        Ok(())
    }
}

// Scatter-gather DMA
pub struct ScatterGatherList {
    pub entries: Vec<DmaEntry>,
}

pub struct DmaEntry {
    pub addr: PhysAddr,
    pub len: usize,
}

impl ScatterGatherList {
    /// Create scatter-gather list from user buffer
    pub fn from_user_buffer(
        buffer: UserBuffer,
        dma_cap: &DmaCapability,
    ) -> Result<Self, DriverError> {
        let mut entries = Vec::new();
        
        for page in buffer.pages() {
            let phys_addr = virt_to_phys(page.virt_addr)?;
            entries.push(DmaEntry {
                addr: phys_addr,
                len: page.len,
            });
        }
        
        Ok(Self { entries })
    }
}
}

Interrupt Handling

Efficient interrupt handling with capability-based access:

#![allow(unused)]
fn main() {
pub struct InterruptHandler {
    vector: u32,
    handler: Box<dyn Fn() -> InterruptResult + Send + Sync>,
}

#[derive(Debug, Clone, Copy)]
pub enum InterruptResult {
    /// Interrupt handled
    Handled,
    
    /// Not our interrupt
    NotHandled,
    
    /// Wake up blocked thread
    WakeThread(ThreadId),
    
    /// Schedule bottom half
    ScheduleBottomHalf,
}

impl InterruptHandler {
    /// Register interrupt handler
    pub fn register(
        vector: u32,
        handler: impl Fn() -> InterruptResult + Send + Sync + 'static,
        interrupt_cap: InterruptCapability,
    ) -> Result<Self, DriverError> {
        // Validate capability
        validate_interrupt_capability(&interrupt_cap, vector)?;
        
        // Register with kernel
        sys_register_interrupt_handler(vector, current_process_id())?;
        
        Ok(Self {
            vector,
            handler: Box::new(handler),
        })
    }
    
    /// Enable interrupt
    pub fn enable(&self) -> Result<(), DriverError> {
        sys_enable_interrupt(self.vector)
    }
    
    /// Disable interrupt
    pub fn disable(&self) -> Result<(), DriverError> {
        sys_disable_interrupt(self.vector)
    }
}

// Message-signaled interrupts (MSI/MSI-X)
pub struct MsiHandler {
    pub vectors: Vec<u32>,
    pub handlers: Vec<InterruptHandler>,
}

impl MsiHandler {
    /// Configure MSI interrupts
    pub fn configure_msi(
        pci_dev: &PciDevice,
        num_vectors: usize,
    ) -> Result<Self, DriverError> {
        let vectors = pci_dev.allocate_msi_vectors(num_vectors)?;
        let mut handlers = Vec::new();
        
        for vector in &vectors {
            let handler = InterruptHandler::register(
                *vector,
                move || handle_msi_interrupt(*vector),
                pci_dev.interrupt_capability(),
            )?;
            handlers.push(handler);
        }
        
        Ok(Self { vectors, handlers })
    }
}
}

Device Classes

Block Device Framework

#![allow(unused)]
fn main() {
#[async_trait]
pub trait BlockDevice: Driver {
    /// Read blocks from device
    async fn read_blocks(
        &self,
        start_block: u64,
        blocks: &mut [Block],
    ) -> Result<usize, BlockError>;
    
    /// Write blocks to device
    async fn write_blocks(
        &self,
        start_block: u64,
        blocks: &[Block],
    ) -> Result<usize, BlockError>;
    
    /// Flush cached writes
    async fn flush(&self) -> Result<(), BlockError>;
    
    /// Get device information
    fn info(&self) -> BlockDeviceInfo;
}

pub struct BlockDeviceInfo {
    pub block_size: usize,
    pub num_blocks: u64,
    pub read_only: bool,
    pub removable: bool,
    pub model: String,
    pub serial: String,
}

pub type Block = [u8; 512]; // Standard block size

// Example NVMe driver implementation
pub struct NvmeDriver {
    regs: RegisterBlock<NvmeRegs>,
    admin_queue: AdminQueue,
    io_queues: Vec<IoQueue>,
    namespaces: Vec<Namespace>,
}

#[async_trait]
impl BlockDevice for NvmeDriver {
    async fn read_blocks(
        &self,
        start_block: u64,
        blocks: &mut [Block],
    ) -> Result<usize, BlockError> {
        let namespace = &self.namespaces[0]; // Primary namespace
        let lba = start_block;
        let num_blocks = blocks.len() as u16;
        
        // Create read command
        let cmd = NvmeCommand::read(namespace.id, lba, num_blocks);
        
        // Submit to I/O queue
        let result = self.io_queues[0].submit_and_wait(cmd).await?;
        
        // Copy data to user buffer
        result.copy_to_blocks(blocks)?;
        
        Ok(blocks.len())
    }
    
    async fn write_blocks(
        &self,
        start_block: u64,
        blocks: &[Block],
    ) -> Result<usize, BlockError> {
        let namespace = &self.namespaces[0];
        let lba = start_block;
        let num_blocks = blocks.len() as u16;
        
        // Create write command
        let cmd = NvmeCommand::write(namespace.id, lba, num_blocks);
        
        // Submit to I/O queue
        self.io_queues[0].submit_and_wait(cmd).await?;
        
        Ok(blocks.len())
    }
}
}

Network Device Framework

#![allow(unused)]
fn main() {
#[async_trait]
pub trait NetworkDevice: Driver {
    /// Send network packet
    async fn send_packet(&self, packet: NetworkPacket) -> Result<(), NetworkError>;
    
    /// Receive network packet
    async fn receive_packet(&self) -> Result<NetworkPacket, NetworkError>;
    
    /// Get MAC address
    fn mac_address(&self) -> MacAddress;
    
    /// Set promiscuous mode
    fn set_promiscuous(&self, enabled: bool) -> Result<(), NetworkError>;
    
    /// Get link status
    fn link_status(&self) -> LinkStatus;
}

pub struct NetworkPacket {
    pub data: Vec<u8>,
    pub timestamp: Instant,
    pub checksum_offload: bool,
}

#[derive(Debug, Clone, Copy)]
pub struct MacAddress([u8; 6]);

#[derive(Debug, Clone, Copy)]
pub enum LinkStatus {
    Up { speed: LinkSpeed, duplex: Duplex },
    Down,
}

#[derive(Debug, Clone, Copy)]
pub enum LinkSpeed {
    Mbps10,
    Mbps100,
    Gbps1,
    Gbps10,
    Gbps25,
    Gbps40,
    Gbps100,
}

// Example Intel e1000 driver
pub struct E1000Driver {
    regs: RegisterBlock<E1000Regs>,
    rx_ring: RxRing,
    tx_ring: TxRing,
    mac_addr: MacAddress,
}

#[async_trait]
impl NetworkDevice for E1000Driver {
    async fn send_packet(&self, packet: NetworkPacket) -> Result<(), NetworkError> {
        // Get next TX descriptor
        let desc = self.tx_ring.next_descriptor()?;
        
        // Set up DMA transfer
        desc.setup_packet(packet)?;
        
        // Ring doorbell
        self.regs.write32(E1000_TDT, self.tx_ring.tail);
        
        // Wait for completion
        desc.wait_completion().await?;
        
        Ok(())
    }
    
    async fn receive_packet(&self) -> Result<NetworkPacket, NetworkError> {
        // Wait for packet
        let desc = self.rx_ring.wait_packet().await?;
        
        // Extract packet data
        let packet = desc.extract_packet()?;
        
        // Refill descriptor
        self.rx_ring.refill_descriptor(desc)?;
        
        Ok(packet)
    }
}
}

Graphics Device Framework

#![allow(unused)]
fn main() {
#[async_trait]
pub trait GraphicsDevice: Driver {
    /// Set display mode
    async fn set_mode(&self, mode: DisplayMode) -> Result<(), GraphicsError>;
    
    /// Get framebuffer
    fn framebuffer(&self) -> Result<Framebuffer, GraphicsError>;
    
    /// Present frame
    async fn present(&self) -> Result<(), GraphicsError>;
    
    /// Wait for vertical blank
    async fn wait_vblank(&self) -> Result<(), GraphicsError>;
}

pub struct DisplayMode {
    pub width: u32,
    pub height: u32,
    pub refresh_rate: u32,
    pub color_depth: ColorDepth,
}

#[derive(Debug, Clone, Copy)]
pub enum ColorDepth {
    Rgb565,
    Rgb888,
    Rgba8888,
}

pub struct Framebuffer {
    pub addr: VirtAddr,
    pub width: u32,
    pub height: u32,
    pub stride: u32,
    pub format: PixelFormat,
}

// Simple framebuffer driver
pub struct SimpleFbDriver {
    framebuffer: Framebuffer,
    mmio_region: MmioRegion,
}

#[async_trait]
impl GraphicsDevice for SimpleFbDriver {
    async fn set_mode(&self, mode: DisplayMode) -> Result<(), GraphicsError> {
        // Simple framebuffer doesn't support mode switching
        Err(GraphicsError::ModeNotSupported)
    }
    
    fn framebuffer(&self) -> Result<Framebuffer, GraphicsError> {
        Ok(self.framebuffer.clone())
    }
    
    async fn present(&self) -> Result<(), GraphicsError> {
        // Simple framebuffer is always presenting
        Ok(())
    }
}
}

Driver Management

Driver Registry

#![allow(unused)]
fn main() {
pub struct DriverRegistry {
    drivers: HashMap<DeviceId, Arc<dyn Driver>>,
    device_tree: DeviceTree,
    hotplug_manager: HotplugManager,
}

impl DriverRegistry {
    /// Register new driver
    pub fn register_driver(
        &mut self,
        driver: Arc<dyn Driver>,
        device_id: DeviceId,
    ) -> Result<(), RegistryError> {
        // Validate driver metadata
        let metadata = driver.metadata();
        self.validate_metadata(&metadata)?;
        
        // Check for conflicts
        if self.drivers.contains_key(&device_id) {
            return Err(RegistryError::DeviceAlreadyClaimed);
        }
        
        // Initialize driver
        let capabilities = self.allocate_capabilities(&metadata)?;
        driver.init(capabilities).await?;
        
        // Add to registry
        self.drivers.insert(device_id, driver);
        
        Ok(())
    }
    
    /// Unregister driver
    pub fn unregister_driver(&mut self, device_id: &DeviceId) -> Result<(), RegistryError> {
        if let Some(driver) = self.drivers.remove(device_id) {
            // Shutdown driver gracefully
            driver.shutdown().await?;
            
            // Revoke capabilities
            self.revoke_capabilities(device_id)?;
        }
        
        Ok(())
    }
    
    /// Handle device hotplug
    pub async fn handle_hotplug(&self, event: HotplugEvent) -> Result<(), RegistryError> {
        match event.event_type {
            HotplugEventType::DeviceAdded => {
                self.probe_device(event.device_id).await?;
            }
            HotplugEventType::DeviceRemoved => {
                self.remove_device(event.device_id).await?;
            }
        }
        
        Ok(())
    }
}
}

Device Discovery

#![allow(unused)]
fn main() {
pub struct DeviceDiscovery {
    pci_bus: PciBus,
    platform_devices: Vec<PlatformDevice>,
}

impl DeviceDiscovery {
    /// Enumerate all devices
    pub fn enumerate_devices(&self) -> Result<Vec<DeviceInfo>, DiscoveryError> {
        let mut devices = Vec::new();
        
        // Enumerate PCI devices
        for device in self.pci_bus.enumerate()? {
            devices.push(DeviceInfo::from_pci(device));
        }
        
        // Enumerate platform devices
        for device in &self.platform_devices {
            devices.push(DeviceInfo::from_platform(device));
        }
        
        Ok(devices)
    }
    
    /// Probe specific device
    pub async fn probe_device(&self, device_id: DeviceId) -> Result<Arc<dyn Driver>, DiscoveryError> {
        let device_info = self.get_device_info(device_id)?;
        
        // Match device to driver
        let driver_name = self.match_driver(&device_info)?;
        
        // Load driver
        let driver = self.load_driver(driver_name).await?;
        
        Ok(driver)
    }
}

pub struct DeviceInfo {
    pub device_id: DeviceId,
    pub vendor_id: u16,
    pub product_id: u16,
    pub device_class: DeviceClass,
    pub subsystem_vendor: Option<u16>,
    pub subsystem_device: Option<u16>,
    pub resources: Vec<DeviceResource>,
}

#[derive(Debug, Clone)]
pub enum DeviceResource {
    MmioRegion { base: PhysAddr, size: usize },
    IoPort { base: u16, size: u16 },
    Interrupt { vector: u32, shared: bool },
    DmaChannel { channel: u8 },
}
}

Power Management

Driver Power States

#![allow(unused)]
fn main() {
#[derive(Debug, Clone, Copy)]
pub enum PowerState {
    /// Fully operational
    D0,
    
    /// Low power, context preserved
    D1,
    
    /// Lower power, some context lost
    D2,
    
    /// Lowest power, most context lost
    D3Hot,
    
    /// Power removed
    D3Cold,
}

#[async_trait]
pub trait PowerManagement {
    /// Set device power state
    async fn set_power_state(&self, state: PowerState) -> Result<(), PowerError>;
    
    /// Get current power state
    fn get_power_state(&self) -> PowerState;
    
    /// Prepare for system sleep
    async fn prepare_sleep(&self) -> Result<(), PowerError>;
    
    /// Resume from system sleep
    async fn resume(&self) -> Result<(), PowerError>;
}

// Example implementation
impl PowerManagement for E1000Driver {
    async fn set_power_state(&self, state: PowerState) -> Result<(), PowerError> {
        match state {
            PowerState::D0 => {
                // Full power
                self.regs.write32(E1000_CTRL, CTRL_NORMAL_OPERATION);
            }
            PowerState::D3Hot => {
                // Low power
                self.regs.write32(E1000_CTRL, CTRL_POWER_DOWN);
            }
            _ => return Err(PowerError::StateNotSupported),
        }
        
        Ok(())
    }
}
}

Performance Optimization

Zero-Copy Data Paths

#![allow(unused)]
fn main() {
pub struct ZeroCopyBuffer {
    /// User virtual address
    user_addr: VirtAddr,
    
    /// Physical pages
    pages: Vec<PhysFrame>,
    
    /// DMA mapping
    dma_addr: PhysAddr,
}

impl ZeroCopyBuffer {
    /// Create from user buffer
    pub fn from_user_buffer(
        user_buffer: UserBuffer,
        direction: DmaDirection,
    ) -> Result<Self, DriverError> {
        // Pin user pages in memory
        let pages = pin_user_pages(user_buffer.addr, user_buffer.len)?;
        
        // Create DMA mapping
        let dma_addr = create_dma_mapping(&pages, direction)?;
        
        Ok(Self {
            user_addr: user_buffer.addr,
            pages,
            dma_addr,
        })
    }
    
    /// Get DMA address for device
    pub fn dma_addr(&self) -> PhysAddr {
        self.dma_addr
    }
}

// Efficient packet processing
pub struct PacketBuffer {
    pub head: usize,
    pub tail: usize,
    pub data: DmaBuffer,
}

impl PacketBuffer {
    /// Reserve headroom for headers
    pub fn reserve_headroom(&mut self, len: usize) {
        self.head += len;
    }
    
    /// Add data to tail
    pub fn push_tail(&mut self, data: &[u8]) -> Result<(), BufferError> {
        if self.tail + data.len() > self.data.size {
            return Err(BufferError::InsufficientSpace);
        }
        
        unsafe {
            let dst = self.data.virt_addr.as_ptr::<u8>().add(self.tail);
            core::ptr::copy_nonoverlapping(data.as_ptr(), dst, data.len());
        }
        
        self.tail += data.len();
        Ok(())
    }
}
}

Interrupt Coalescing

#![allow(unused)]
fn main() {
pub struct InterruptCoalescing {
    /// Maximum interrupts per second
    max_rate: u32,
    
    /// Minimum packets before interrupt
    min_packets: u32,
    
    /// Maximum delay before interrupt (μs)
    max_delay: u32,
}

impl InterruptCoalescing {
    /// Configure interrupt coalescing
    pub fn configure(&self, regs: &RegisterBlock<E1000Regs>) {
        // Set interrupt throttling
        let itr = 1_000_000 / self.max_rate; // Convert to ITR units
        regs.write32(E1000_ITR, itr);
        
        // Set receive delay timer
        regs.write32(E1000_RDTR, self.max_delay / 256);
        
        // Set receive interrupt packet count
        regs.write32(E1000_RADV, self.min_packets);
    }
}
}

Driver Development

Driver Template

#![allow(unused)]
fn main() {
use veridian_driver_framework::*;

pub struct MyDriver {
    regs: RegisterBlock<MyDeviceRegs>,
    interrupt_handler: InterruptHandler,
    dma_buffer: DmaBuffer,
}

#[async_trait]
impl Driver for MyDriver {
    async fn init(&mut self, caps: HardwareCapabilities) -> Result<(), DriverError> {
        // Map MMIO regions
        self.regs = RegisterBlock::new(caps.mmio_regions[0].clone())?;
        
        // Allocate DMA buffer
        self.dma_buffer = DmaBuffer::allocate(
            PAGE_SIZE,
            DmaDirection::Bidirectional,
            &caps.dma_capability.unwrap(),
        )?;
        
        // Register interrupt handler
        self.interrupt_handler = InterruptHandler::register(
            caps.interrupts[0].vector,
            || self.handle_interrupt(),
            caps.interrupts[0].capability,
        )?;
        
        // Initialize device
        self.regs.write32(CONTROL_REG, CONTROL_RESET);
        
        Ok(())
    }
    
    async fn start(&mut self) -> Result<(), DriverError> {
        // Enable device
        self.regs.write32(CONTROL_REG, CONTROL_ENABLE);
        self.interrupt_handler.enable()?;
        
        Ok(())
    }
    
    async fn handle_interrupt(&self, vector: u32) -> Result<(), DriverError> {
        let status = self.regs.read32(STATUS_REG);
        
        if status & STATUS_RX_READY != 0 {
            // Handle received data
            self.handle_rx().await?;
        }
        
        if status & STATUS_TX_COMPLETE != 0 {
            // Handle transmit completion
            self.handle_tx_complete().await?;
        }
        
        // Clear interrupt
        self.regs.write32(STATUS_REG, status);
        
        Ok(())
    }
    
    async fn shutdown(&mut self) -> Result<(), DriverError> {
        // Disable interrupts
        self.interrupt_handler.disable()?;
        
        // Reset device
        self.regs.write32(CONTROL_REG, CONTROL_RESET);
        
        Ok(())
    }
    
    fn metadata(&self) -> DriverMetadata {
        DriverMetadata {
            name: "MyDriver".to_string(),
            version: Version::new(1, 0, 0),
            vendor_id: Some(0x1234),
            device_id: Some(0x5678),
            device_class: DeviceClass::Network,
            capabilities_required: vec![
                CapabilityType::Mmio,
                CapabilityType::Interrupt,
                CapabilityType::Dma,
            ],
        }
    }
}
}

Build System Integration

# Cargo.toml for driver
[package]
name = "my-driver"
version = "0.1.0"
edition = "2021"

[dependencies]
veridian-driver-framework = { path = "../../framework" }
async-trait = "0.1"
log = "0.4"

[lib]
crate-type = ["cdylib"]

# Driver manifest
[package.metadata.veridian]
device-class = "network"
vendor-id = 0x1234
device-id = 0x5678

Future Enhancements

Planned Features

Driver Verification: Formal verification of critical drivers
GPU Support: High-performance GPU drivers with compute capabilities
Real-Time Drivers: Deterministic driver execution for RT systems
Driver Sandboxing: Additional isolation using hardware features
Hot-Patching: Update drivers without system restart

Research Areas

AI-Driven Optimization: Machine learning for driver performance tuning
Hardware Offload: Driver logic implemented in hardware
Distributed Drivers: Driver components across multiple machines
Quantum Computing: Quantum device driver interfaces

This driver architecture provides a secure, maintainable, and high-performance foundation for device support in VeridianOS while maintaining the microkernel's principles of isolation and capability-based security.

VeridianOS Developer Guide