RP2040 monotonic, rename systick monotonic to not have double name

4 files changed, 152 insertions, 1 deletions

diff --git a/rtic-monotonics/Cargo.toml b/rtic-monotonics/Cargo.toml
index 4014fe7..2e75bdb 100644
--- a/rtic-monotonics/Cargo.toml
+++ b/rtic-monotonics/Cargo.toml
@@ -23,7 +23,12 @@ fugit = { version = "0.3.6", features = ["defmt"] }
 rtic-time = { version = "1.0.0-alpha.0", path = "../rtic-time" }
 atomic-polyfill = "1"
 cfg-if = "1.0.0"
+rp2040-pac = { version = ">=0.2.0,<0.5", optional = true }
 
 [features]
+default = []
+
 systick_100hz = []
 systick_10khz = []
+
+rp2040 = ["dep:rp2040-pac"]
diff --git a/rtic-monotonics/src/lib.rs b/rtic-monotonics/src/lib.rs
index 1e23088..fb5dc8a 100644
--- a/rtic-monotonics/src/lib.rs
+++ b/rtic-monotonics/src/lib.rs
@@ -9,4 +9,7 @@
 
 pub use rtic_time::{Monotonic, TimeoutError, TimerQueue};
 
-pub mod systick_monotonic;
+pub mod systick;
+
+#[cfg(feature = "rp2040")]
+pub mod rp2040;
diff --git a/rtic-monotonics/src/rp2040.rs b/rtic-monotonics/src/rp2040.rs
new file mode 100644
index 0000000..448c388
--- /dev/null
+++ b/rtic-monotonics/src/rp2040.rs
@@ -0,0 +1,143 @@
+//! A monotonic implementation for RP2040's Timer peripheral.
+
+use super::Monotonic;
+pub use super::{TimeoutError, TimerQueue};
+use core::future::Future;
+use embedded_hal_async::delay::DelayUs;
+pub use fugit::ExtU64;
+use rp2040_pac::{timer, Interrupt, RESETS, TIMER};
+
+/// Timer implementing `rtic_monotonic::Monotonic` which runs at 1 MHz.
+pub struct Timer;
+
+impl Timer {
+    /// Start a `Monotonic` based on RP2040's Timer.
+    pub fn start(timer: TIMER, resets: &mut RESETS) {
+        resets.reset.modify(|_, w| w.timer().clear_bit());
+        while resets.reset_done.read().timer().bit_is_clear() {}
+        timer.inte.modify(|_, w| w.alarm_0().set_bit());
+
+        TIMER_QUEUE.initialize(Self {});
+    }
+
+    fn timer() -> &'static timer::RegisterBlock {
+        unsafe { &*TIMER::ptr() }
+    }
+}
+
+static TIMER_QUEUE: TimerQueue<Timer> = TimerQueue::new();
+
+// Forward timerqueue interface
+impl Timer {
+    /// Used to access the underlying timer queue
+    #[doc(hidden)]
+    pub fn __tq() -> &'static TimerQueue<Timer> {
+        &TIMER_QUEUE
+    }
+
+    /// Timeout at a specific time.
+    pub async fn timeout_at<F: Future>(
+        instant: <Self as Monotonic>::Instant,
+        future: F,
+    ) -> Result<F::Output, TimeoutError> {
+        TIMER_QUEUE.timeout_at(instant, future).await
+    }
+
+    /// Timeout after a specific duration.
+    #[inline]
+    pub async fn timeout_after<F: Future>(
+        duration: <Self as Monotonic>::Duration,
+        future: F,
+    ) -> Result<F::Output, TimeoutError> {
+        TIMER_QUEUE.timeout_after(duration, future).await
+    }
+
+    /// Delay for some duration of time.
+    #[inline]
+    pub async fn delay(duration: <Self as Monotonic>::Duration) {
+        TIMER_QUEUE.delay(duration).await;
+    }
+
+    /// Delay to some specific time instant.
+    pub async fn delay_until(instant: <Self as Monotonic>::Instant) {
+        TIMER_QUEUE.delay_until(instant).await;
+    }
+}
+
+impl Monotonic for Timer {
+    type Instant = fugit::TimerInstantU64<1_000_000>;
+    type Duration = fugit::TimerDurationU64<1_000_000>;
+
+    const ZERO: Self::Instant = Self::Instant::from_ticks(0);
+
+    fn now() -> Self::Instant {
+        let timer = Self::timer();
+
+        let mut hi0 = timer.timerawh.read().bits();
+        loop {
+            let low = timer.timerawl.read().bits();
+            let hi1 = timer.timerawh.read().bits();
+            if hi0 == hi1 {
+                break Self::Instant::from_ticks((u64::from(hi0) << 32) | u64::from(low));
+            }
+            hi0 = hi1;
+        }
+    }
+
+    fn set_compare(instant: Self::Instant) {
+        let now = Self::now();
+
+        let max = u32::MAX as u64;
+
+        // Since the timer may or may not overflow based on the requested compare val, we check
+        // how many ticks are left.
+        let val = match instant.checked_duration_since(now) {
+            Some(x) if x.ticks() <= max => instant.duration_since_epoch().ticks() & max, // Will not overflow
+            _ => 0, // Will overflow or in the past, set the same value as after overflow to not get extra interrupts
+        };
+
+        Self::timer()
+            .alarm0
+            .write(|w| unsafe { w.bits(val as u32) });
+    }
+
+    fn clear_compare_flag() {
+        Self::timer().intr.modify(|_, w| w.alarm_0().set_bit());
+    }
+
+    fn pend_interrupt() {
+        cortex_m::peripheral::NVIC::pend(Interrupt::TIMER_IRQ_0);
+    }
+
+    fn on_interrupt() {}
+
+    fn enable_timer() {}
+
+    fn disable_timer() {}
+}
+
+impl DelayUs for Timer {
+    type Error = core::convert::Infallible;
+
+    async fn delay_us(&mut self, us: u32) -> Result<(), Self::Error> {
+        TIMER_QUEUE.delay((us as u64).micros()).await;
+        Ok(())
+    }
+
+    async fn delay_ms(&mut self, ms: u32) -> Result<(), Self::Error> {
+        TIMER_QUEUE.delay((ms as u64).millis()).await;
+        Ok(())
+    }
+}
+
+/// Register the Timer interrupt for the monotonic.
+#[macro_export]
+macro_rules! make_rp2040_monotonic_handler {
+    () => {
+        #[no_mangle]
+        #[allow(non_snake_case)]
+        unsafe extern "C" fn TIMER_IRQ_0() {
+            rtic_monotonics::rp2040::Timer::__tq().on_monotonic_interrupt();
+        }
+    };
+}
diff --git a/rtic-monotonics/src/systick_monotonic.rs b/rtic-monotonics/src/systick.rs
index 885da92..885da92 100644
--- a/rtic-monotonics/src/systick_monotonic.rs
+++ b/rtic-monotonics/src/systick.rs