Add new driver implementations and workspace updates

drivers/0x0d_timer_rust/src/timer_driver.rs

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+//! @file timer_driver.rs
+//! @brief Implementation of the repeating timer driver
+//! @author Kevin Thomas
+//! @date 2025
+//!
+//! MIT License
+//!
+//! Copyright (c) 2025 Kevin Thomas
+//!
+//! Permission is hereby granted, free of charge, to any person obtaining a copy
+//! of this software and associated documentation files (the "Software"), to deal
+//! in the Software without restriction, including without limitation the rights
+//! to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//! copies of the Software, and to permit persons to whom the Software is
+//! furnished to do so, subject to the following conditions:
+//!
+//! The above copyright notice and this permission notice shall be included in
+//! all copies or substantial portions of the Software.
+//!
+//! THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//! IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//! FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//! AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//! LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//! OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+//! SOFTWARE.
+
+/// Default heartbeat message printed by the timer callback.
+pub const HEARTBEAT_MSG: &[u8] = b"Timer heartbeat\r\n";
+
+/// Default timer period in milliseconds.
+pub const DEFAULT_PERIOD_MS: u32 = 1_000;
+
+/// Timer driver state tracking whether the repeating timer is active.
+///
+/// Mirrors the C driver's `g_timer_active` / `g_user_callback` globals
+/// as a structured state machine testable on the host.
+pub struct TimerDriverState {
+    /// Whether the repeating timer is currently active.
+    active: bool,
+    /// Configured period in milliseconds.
+    period_ms: u32,
+    /// Number of times the callback has fired.
+    fire_count: u32,
+}
+
+impl TimerDriverState {
+    /// Create a new idle timer driver state.
+    ///
+    /// # Returns
+    ///
+    /// A `TimerDriverState` in the inactive state with zero fire count.
+    pub fn new() -> Self {
+        Self {
+            active: false,
+            period_ms: 0,
+            fire_count: 0,
+        }
+    }
+
+    /// Start the repeating timer with the given period.
+    ///
+    /// If the timer is already active it is first cancelled, matching
+    /// the C driver's `timer_driver_start()` behaviour.
+    ///
+    /// # Arguments
+    ///
+    /// * `period_ms` - Interval between callbacks in milliseconds.
+    pub fn start(&mut self, period_ms: u32) {
+        if self.active {
+            self.cancel();
+        }
+        self.period_ms = period_ms;
+        self.active = true;
+    }
+
+    /// Cancel the active repeating timer.
+    ///
+    /// Safe to call even if the timer is already inactive, matching
+    /// the C driver's `timer_driver_cancel()` behaviour.
+    pub fn cancel(&mut self) {
+        self.active = false;
+    }
+
+    /// Return whether the timer is currently active.
+    ///
+    /// # Returns
+    ///
+    /// `true` if a repeating timer is running, `false` otherwise.
+    pub fn is_active(&self) -> bool {
+        self.active
+    }
+
+    /// Return the configured timer period in milliseconds.
+    ///
+    /// # Returns
+    ///
+    /// The period set by the most recent `start()` call.
+    pub fn period_ms(&self) -> u32 {
+        self.period_ms
+    }
+
+    /// Return the total number of times the callback has fired.
+    ///
+    /// # Returns
+    ///
+    /// Cumulative fire count since construction.
+    pub fn fire_count(&self) -> u32 {
+        self.fire_count
+    }
+
+    /// Record that the callback has fired once.
+    ///
+    /// Called by the board-level shim each time the hardware alarm
+    /// triggers. Returns `true` to keep the timer repeating (matching
+    /// the C `_heartbeat_callback` return value).
+    ///
+    /// # Returns
+    ///
+    /// `true` if the timer should continue repeating.
+    pub fn on_fire(&mut self) -> bool {
+        if !self.active {
+            return false;
+        }
+        self.fire_count += 1;
+        true
+    }
+}
+
+/// Format the heartbeat message into a caller-supplied buffer.
+///
+/// Writes the fixed `HEARTBEAT_MSG` bytes and returns the number
+/// of bytes written.
+///
+/// # Arguments
+///
+/// * `buf` - Destination buffer (must be at least `HEARTBEAT_MSG.len()` bytes).
+///
+/// # Returns
+///
+/// Number of bytes written to `buf`.
+pub fn format_heartbeat(buf: &mut [u8]) -> usize {
+    let len = HEARTBEAT_MSG.len();
+    buf[..len].copy_from_slice(HEARTBEAT_MSG);
+    len
+}
+
+/// Format a timer-started banner message.
+///
+/// Writes "Repeating timer started (XXXX ms)\r\n" into `buf` and
+/// returns the number of bytes written.
+///
+/// # Arguments
+///
+/// * `buf` - Destination buffer (must be at least 40 bytes).
+/// * `period_ms` - Timer period to include in the message.
+///
+/// # Returns
+///
+/// Number of bytes written to `buf`.
+pub fn format_started(buf: &mut [u8], period_ms: u32) -> usize {
+    let prefix = b"Repeating timer started (";
+    let mut pos = prefix.len();
+    buf[..pos].copy_from_slice(prefix);
+    pos += format_u32(&mut buf[pos..], period_ms);
+    let suffix = b" ms)\r\n";
+    buf[pos..pos + suffix.len()].copy_from_slice(suffix);
+    pos + suffix.len()
+}
+
+/// Format an unsigned 32-bit integer as decimal ASCII.
+///
+/// # Arguments
+///
+/// * `buf` - Destination buffer.
+/// * `value` - Value to format.
+///
+/// # Returns
+///
+/// Number of ASCII digits written.
+fn format_u32(buf: &mut [u8], value: u32) -> usize {
+    if value == 0 {
+        buf[0] = b'0';
+        return 1;
+    }
+    let mut tmp = [0u8; 10];
+    let mut n = 0usize;
+    let mut v = value;
+    while v > 0 {
+        tmp[n] = b'0' + (v % 10) as u8;
+        v /= 10;
+        n += 1;
+    }
+    for i in 0..n {
+        buf[i] = tmp[n - 1 - i];
+    }
+    n
+}
+
+#[cfg(test)]
+mod tests {
+    // Import all parent module items
+    use super::*;
+
+    #[test]
+    fn new_state_is_inactive() {
+        let state = TimerDriverState::new();
+        assert!(!state.is_active());
+        assert_eq!(state.period_ms(), 0);
+        assert_eq!(state.fire_count(), 0);
+    }
+
+    #[test]
+    fn start_activates_timer() {
+        let mut state = TimerDriverState::new();
+        state.start(1_000);
+        assert!(state.is_active());
+        assert_eq!(state.period_ms(), 1_000);
+    }
+
+    #[test]
+    fn cancel_deactivates_timer() {
+        let mut state = TimerDriverState::new();
+        state.start(1_000);
+        state.cancel();
+        assert!(!state.is_active());
+    }
+
+    #[test]
+    fn cancel_when_inactive_is_safe() {
+        let mut state = TimerDriverState::new();
+        state.cancel();
+        assert!(!state.is_active());
+    }
+
+    #[test]
+    fn start_while_active_cancels_and_restarts() {
+        let mut state = TimerDriverState::new();
+        state.start(500);
+        state.start(2_000);
+        assert!(state.is_active());
+        assert_eq!(state.period_ms(), 2_000);
+    }
+
+    #[test]
+    fn on_fire_increments_count() {
+        let mut state = TimerDriverState::new();
+        state.start(1_000);
+        assert!(state.on_fire());
+        assert_eq!(state.fire_count(), 1);
+        assert!(state.on_fire());
+        assert_eq!(state.fire_count(), 2);
+    }
+
+    #[test]
+    fn on_fire_returns_false_when_inactive() {
+        let mut state = TimerDriverState::new();
+        assert!(!state.on_fire());
+        assert_eq!(state.fire_count(), 0);
+    }
+
+    #[test]
+    fn on_fire_after_cancel_returns_false() {
+        let mut state = TimerDriverState::new();
+        state.start(1_000);
+        assert!(state.on_fire());
+        state.cancel();
+        assert!(!state.on_fire());
+        assert_eq!(state.fire_count(), 1);
+    }
+
+    #[test]
+    fn format_heartbeat_matches_c_output() {
+        let mut buf = [0u8; 32];
+        let n = format_heartbeat(&mut buf);
+        assert_eq!(&buf[..n], b"Timer heartbeat\r\n");
+    }
+
+    #[test]
+    fn format_started_1000ms() {
+        let mut buf = [0u8; 48];
+        let n = format_started(&mut buf, 1_000);
+        assert_eq!(&buf[..n], b"Repeating timer started (1000 ms)\r\n");
+    }
+
+    #[test]
+    fn format_started_single_digit() {
+        let mut buf = [0u8; 48];
+        let n = format_started(&mut buf, 5);
+        assert_eq!(&buf[..n], b"Repeating timer started (5 ms)\r\n");
+    }
+
+    #[test]
+    fn format_u32_zero() {
+        let mut buf = [0u8; 10];
+        let n = format_u32(&mut buf, 0);
+        assert_eq!(&buf[..n], b"0");
+    }
+
+    #[test]
+    fn format_u32_large_value() {
+        let mut buf = [0u8; 10];
+        let n = format_u32(&mut buf, 123456);
+        assert_eq!(&buf[..n], b"123456");
+    }
+
+    #[test]
+    fn default_period_matches_c_demo() {
+        assert_eq!(DEFAULT_PERIOD_MS, 1_000);
+    }
+}