store waker

.github/workflows/clippy.yaml

@@ -29,7 +29,8 @@ jobs:
       - name: Run clippy (no features)
         run: cargo clippy --all --no-default-features -- -D warnings
       - name: Run clippy (all features)
-        run: cargo clippy --all --all-features -- -D warnings
+        # We exclude riscv-peripheral because it's not yet stable-compliant
+        run: cargo clippy --exclude riscv-peripheral --all --all-features -- -D warnings
   
   # Additonal clippy checks for riscv-rt
   clippy-riscv-rt:

.github/workflows/riscv-peripheral.yaml

@@ -33,8 +33,9 @@ jobs:
         targets: ${{ matrix.target }}
     - name: Build (no features)
       run: cargo build --package riscv-peripheral --target ${{ matrix.target }}
-    - name: Build (all features)
-      run: cargo build --package riscv-peripheral --target ${{ matrix.target }} --all-features
+    # not yet, let's wait for 1.75.0
+    # - name: Build (all features)
+    #  run: cargo build --package riscv-peripheral --target ${{ matrix.target }} --all-features
 
   # On MacOS, Ubuntu, and Windows, we run the tests.
   build-others:
@@ -47,8 +48,9 @@ jobs:
       - uses: dtolnay/rust-toolchain@stable
       - name: Build (no features)
         run: cargo test --package riscv-peripheral
-      - name: Build (all features)
-        run: cargo test --package riscv-peripheral --all-features
+      # not yet, let's wait for 1.75.0
+      # - name: Build (all features)
+      #  run: cargo test --package riscv-peripheral --all-features
 
   # Job to check that all the builds succeeded
   build-check:

riscv-peripheral/Cargo.toml

@@ -7,12 +7,12 @@ edition = "2021"
 
 [dependencies]
 embedded-hal = "1.0.0-rc.2"
-# embedded-hal-async = { version = "1.0.0-rc.1", optional =  true }
+embedded-hal-async = { version = "1.0.0-rc.2", optional =  true }
 riscv = { path = "../riscv", version = "0.10" }
 riscv-pac = { path = "../riscv-pac", version = "0.1.0" }
 
 [features]
-# hal-async = ["embedded-hal-async"]
+hal-async = ["embedded-hal-async"]
 
 [package.metadata.docs.rs]
 default-target = "riscv64imac-unknown-none-elf"

riscv-peripheral/src/hal_async/aclint.rs

@@ -2,23 +2,29 @@
 
 use crate::aclint::mtimer::MTIME;
 pub use crate::hal::aclint::Delay;
-pub use crate::hal_async::delay::DelayUs;
+pub use crate::hal_async::delay::DelayNs;
 use core::{
     future::Future,
     pin::Pin,
-    task::{Context, Poll},
+    task::{Context, Poll, Waker},
 };
 
 struct DelayAsync {
     mtime: MTIME,
     t0: u64,
     n_ticks: u64,
+    waker: Option<Waker>,
 }
 
 impl DelayAsync {
     pub fn new(mtime: MTIME, n_ticks: u64) -> Self {
         let t0 = mtime.read();
-        Self { mtime, t0, n_ticks }
+        Self {
+            mtime,
+            t0,
+            n_ticks,
+            waker: None,
+        }
     }
 }
 
@@ -26,15 +32,32 @@ impl Future for DelayAsync {
     type Output = ();
 
     #[inline]
-    fn poll(self: Pin<&mut Self>, _cx: &mut Context<'_>) -> Poll<Self::Output> {
+    fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
         match self.mtime.read().wrapping_sub(self.t0) < self.n_ticks {
-            true => Poll::Pending,
-            false => Poll::Ready(()),
+            true => {
+                self.get_mut().waker = Some(cx.waker().clone());
+                Poll::Pending
+            }
+            false => {
+                if let Some(waker) = self.get_mut().waker.take() {
+                    waker.wake();
+                } else {
+                    // corner case: delay expired before polling for the first time
+                    cx.waker().wake_by_ref();
+                };
+                Poll::Ready(())
+            }
         }
     }
 }
 
-impl DelayUs for Delay {
+impl DelayNs for Delay {
+    #[inline]
+    async fn delay_ns(&mut self, ns: u32) {
+        let n_ticks = ns as u64 * self.get_freq() as u64 / 1_000_000_000;
+        DelayAsync::new(self.get_mtime(), n_ticks).await;
+    }
+
     #[inline]
     async fn delay_us(&mut self, us: u32) {
         let n_ticks = us as u64 * self.get_freq() as u64 / 1_000_000;

riscv-peripheral/src/lib.rs

@@ -7,8 +7,8 @@ pub use riscv; // re-export riscv crate to allow macros to use it
 
 pub mod common; // common definitions for all peripherals
 pub mod hal; // trait implementations for embedded-hal
-             // #[cfg(feature = "hal-async")]
-             // pub mod hal_async; // async trait implementations for embedded-hal
+#[cfg(feature = "hal-async")]
+pub mod hal_async; // async trait implementations for embedded-hal
 pub mod macros; // macros for easing the definition of peripherals in PACs
 
 pub mod aclint; // ACLINT and CLINT peripherals