Merge pull request #2854 from ericyanush/feat/add-bxcan-sleep-wakeup

Add stm32 bxCAN sleep/wakeup functionality

2 files changed, 77 insertions, 4 deletions

diff --git a/embassy-stm32/src/can/bxcan/mod.rs b/embassy-stm32/src/can/bxcan/mod.rs
index 65fd0e9c2..912634b84 100644
--- a/embassy-stm32/src/can/bxcan/mod.rs
+++ b/embassy-stm32/src/can/bxcan/mod.rs
@@ -67,12 +67,23 @@ pub struct SceInterruptHandler<T: Instance> {
 
 impl<T: Instance> interrupt::typelevel::Handler<T::SCEInterrupt> for SceInterruptHandler<T> {
     unsafe fn on_interrupt() {
-        // info!("sce irq");
+        info!("sce irq");
         let msr = T::regs().msr();
         let msr_val = msr.read();
 
-        if msr_val.erri() {
-            msr.modify(|v| v.set_erri(true));
+        if msr_val.slaki() {
+            msr.modify(|m| m.set_slaki(true));
+            T::state().err_waker.wake();
+        } else if msr_val.erri() {
+            info!("Error interrupt");
+            // Disable the interrupt, but don't acknowledge the error, so that it can be
+            // forwarded off the the bus message consumer. If we don't provide some way for
+            // downstream code to determine that it has already provided this bus error instance
+            // to the bus message consumer, we are doomed to re-provide a single error instance for
+            // an indefinite amount of time.
+            let ier = T::regs().ier();
+            ier.modify(|i| i.set_errie(false));
+
             T::state().err_waker.wake();
         }
     }
@@ -180,6 +191,10 @@ impl<'d, T: Instance> Can<'d, T> {
                 w.set_fmpie(0, true);
                 w.set_fmpie(1, true);
                 w.set_tmeie(true);
+                w.set_bofie(true);
+                w.set_epvie(true);
+                w.set_ewgie(true);
+                w.set_lecie(true);
             });
 
             T::regs().mcr().write(|w| {
@@ -239,6 +254,50 @@ impl<'d, T: Instance> Can<'d, T> {
         }
     }
 
+    /// Enables or disables the peripheral from automatically wakeup when a SOF is detected on the bus
+    /// while the peripheral is in sleep mode
+    pub fn set_automatic_wakeup(&mut self, enabled: bool) {
+        Registers(T::regs()).set_automatic_wakeup(enabled);
+    }
+
+    /// Manually wake the peripheral from sleep mode.
+    ///
+    /// Waking the peripheral manually does not trigger a wake-up interrupt.
+    /// This will wait until the peripheral has acknowledged it has awoken from sleep mode
+    pub fn wakeup(&mut self) {
+        Registers(T::regs()).wakeup()
+    }
+
+    /// Check if the peripheral is currently in sleep mode
+    pub fn is_sleeping(&self) -> bool {
+        T::regs().msr().read().slak()
+    }
+
+    /// Put the peripheral in sleep mode
+    ///
+    /// When the peripherial is in sleep mode, messages can still be queued for transmission
+    /// and any previously received messages can be read from the receive FIFOs, however
+    /// no messages will be transmitted and no additional messages will be received.
+    ///
+    /// If the peripheral has automatic wakeup enabled, when a Start-of-Frame is detected
+    /// the peripheral will automatically wake and receive the incoming message.
+    pub async fn sleep(&mut self) {
+        T::regs().ier().modify(|i| i.set_slkie(true));
+        T::regs().mcr().modify(|m| m.set_sleep(true));
+
+        poll_fn(|cx| {
+            T::state().err_waker.register(cx.waker());
+            if self.is_sleeping() {
+                Poll::Ready(())
+            } else {
+                Poll::Pending
+            }
+        })
+        .await;
+
+        T::regs().ier().modify(|i| i.set_slkie(false));
+    }
+
     /// Queues the message to be sent.
     ///
     /// If the TX queue is full, this will wait until there is space, therefore exerting backpressure.
diff --git a/embassy-stm32/src/can/bxcan/registers.rs b/embassy-stm32/src/can/bxcan/registers.rs
index 732567797..446f3ad6f 100644
--- a/embassy-stm32/src/can/bxcan/registers.rs
+++ b/embassy-stm32/src/can/bxcan/registers.rs
@@ -145,7 +145,21 @@ impl Registers {
     }
 
     pub fn curr_error(&self) -> Option<BusError> {
-        let err = { self.0.esr().read() };
+        if !self.0.msr().read().erri() {
+            // This ensures that once a single error instance has
+            // been acknowledged and forwared to the bus message consumer
+            // we don't continue to re-forward the same error occurrance for an
+            // in-definite amount of time.
+            return None;
+        }
+
+        // Since we have not already acknowledge the error, and the interrupt was
+        // disabled in the ISR, we will acknowledge the current error and re-enable the interrupt
+        // so futher errors are captured
+        self.0.msr().modify(|m| m.set_erri(true));
+        self.0.ier().modify(|i| i.set_errie(true));
+
+        let err = self.0.esr().read();
         if err.boff() {
             return Some(BusError::BusOff);
         } else if err.epvf() {