Merge pull request #1578 from schphil/can-split

stm32 can split method

embassy-stm32/src/can/bxcan.rs

@@ -1,3 +1,4 @@
+use core::cell::{RefCell, RefMut};
 use core::future::poll_fn;
 use core::marker::PhantomData;
 use core::ops::{Deref, DerefMut};
@@ -72,7 +73,7 @@ impl<T: Instance> interrupt::typelevel::Handler<T::SCEInterrupt> for SceInterrup
 }
 
 pub struct Can<'d, T: Instance> {
-    can: bxcan::Can<BxcanInstance<'d, T>>,
+    pub can: RefCell<bxcan::Can<BxcanInstance<'d, T>>>,
 }
 
 #[derive(Debug)]
@@ -147,19 +148,24 @@ impl<'d, T: Instance> Can<'d, T> {
         tx.set_as_af(tx.af_num(), AFType::OutputPushPull);
 
         let can = bxcan::Can::builder(BxcanInstance(peri)).leave_disabled();
-        Self { can }
+        let can_ref_cell = RefCell::new(can);
+        Self { can: can_ref_cell }
     }
 
     pub fn set_bitrate(&mut self, bitrate: u32) {
         let bit_timing = Self::calc_bxcan_timings(T::frequency(), bitrate).unwrap();
-        self.can.modify_config().set_bit_timing(bit_timing).leave_disabled();
+        self.can
+            .borrow_mut()
+            .modify_config()
+            .set_bit_timing(bit_timing)
+            .leave_disabled();
     }
 
     /// Queues the message to be sent but exerts backpressure
     pub async fn write(&mut self, frame: &Frame) -> bxcan::TransmitStatus {
         poll_fn(|cx| {
             T::state().tx_waker.register(cx.waker());
-            if let Ok(status) = self.can.transmit(frame) {
+            if let Ok(status) = self.can.borrow_mut().transmit(frame) {
                 return Poll::Ready(status);
             }
 
@@ -341,6 +347,79 @@ impl<'d, T: Instance> Can<'d, T> {
         // Pack into BTR register values
         Some((sjw - 1) << 24 | (bs1 as u32 - 1) << 16 | (bs2 as u32 - 1) << 20 | (prescaler as u32 - 1))
     }
+
+    pub fn split<'c>(&'c self) -> (CanTx<'c, 'd, T>, CanRx<'c, 'd, T>) {
+        (CanTx { can: &self.can }, CanRx { can: &self.can })
+    }
+
+    pub fn as_mut(&self) -> RefMut<'_, bxcan::Can<BxcanInstance<'d, T>>> {
+        self.can.borrow_mut()
+    }
+}
+
+pub struct CanTx<'c, 'd, T: Instance> {
+    can: &'c RefCell<bxcan::Can<BxcanInstance<'d, T>>>,
+}
+
+impl<'c, 'd, T: Instance> CanTx<'c, 'd, T> {
+    pub async fn write(&mut self, frame: &Frame) -> bxcan::TransmitStatus {
+        poll_fn(|cx| {
+            T::state().tx_waker.register(cx.waker());
+            if let Ok(status) = self.can.borrow_mut().transmit(frame) {
+                return Poll::Ready(status);
+            }
+
+            Poll::Pending
+        })
+        .await
+    }
+
+    pub async fn flush(&self, mb: bxcan::Mailbox) {
+        poll_fn(|cx| {
+            T::state().tx_waker.register(cx.waker());
+            if T::regs().tsr().read().tme(mb.index()) {
+                return Poll::Ready(());
+            }
+
+            Poll::Pending
+        })
+        .await;
+    }
+}
+
+#[allow(dead_code)]
+pub struct CanRx<'c, 'd, T: Instance> {
+    can: &'c RefCell<bxcan::Can<BxcanInstance<'d, T>>>,
+}
+
+impl<'c, 'd, T: Instance> CanRx<'c, 'd, T> {
+    pub async fn read(&mut self) -> Result<(u16, bxcan::Frame), BusError> {
+        poll_fn(|cx| {
+            T::state().err_waker.register(cx.waker());
+            if let Poll::Ready((time, frame)) = T::state().rx_queue.recv().poll_unpin(cx) {
+                return Poll::Ready(Ok((time, frame)));
+            } else if let Some(err) = self.curr_error() {
+                return Poll::Ready(Err(err));
+            }
+
+            Poll::Pending
+        })
+        .await
+    }
+
+    fn curr_error(&self) -> Option<BusError> {
+        let err = { T::regs().esr().read() };
+        if err.boff() {
+            return Some(BusError::BusOff);
+        } else if err.epvf() {
+            return Some(BusError::BusPassive);
+        } else if err.ewgf() {
+            return Some(BusError::BusWarning);
+        } else if let Some(err) = err.lec().into_bus_err() {
+            return Some(err);
+        }
+        None
+    }
 }
 
 enum RxFifo {
@@ -358,7 +437,7 @@ impl<'d, T: Instance> Drop for Can<'d, T> {
 }
 
 impl<'d, T: Instance> Deref for Can<'d, T> {
-    type Target = bxcan::Can<BxcanInstance<'d, T>>;
+    type Target = RefCell<bxcan::Can<BxcanInstance<'d, T>>>;
 
     fn deref(&self) -> &Self::Target {
         &self.can

examples/stm32f4/src/bin/can.rs

@@ -2,8 +2,8 @@
 #![no_main]
 #![feature(type_alias_impl_trait)]
 
-use cortex_m_rt::entry;
 use defmt::*;
+use embassy_executor::Spawner;
 use embassy_stm32::bind_interrupts;
 use embassy_stm32::can::bxcan::filter::Mask32;
 use embassy_stm32::can::bxcan::{Fifo, Frame, StandardId};
@@ -19,8 +19,8 @@ bind_interrupts!(struct Irqs {
     CAN1_TX => TxInterruptHandler<CAN1>;
 });
 
-#[entry]
-fn main() -> ! {
+#[embassy_executor::main]
+async fn main(_spawner: Spawner) {
     info!("Hello World!");
 
     let mut p = embassy_stm32::init(Default::default());
@@ -34,9 +34,12 @@ fn main() -> ! {
 
     let mut can = Can::new(p.CAN1, p.PA11, p.PA12, Irqs);
 
-    can.modify_filters().enable_bank(0, Fifo::Fifo0, Mask32::accept_all());
+    can.as_mut()
+        .modify_filters()
+        .enable_bank(0, Fifo::Fifo0, Mask32::accept_all());
 
-    can.modify_config()
+    can.as_mut()
+        .modify_config()
         .set_bit_timing(0x001c0003) // http://www.bittiming.can-wiki.info/
         .set_loopback(true) // Receive own frames
         .set_silent(true)
@@ -45,9 +48,8 @@ fn main() -> ! {
     let mut i: u8 = 0;
     loop {
         let tx_frame = Frame::new_data(unwrap!(StandardId::new(i as _)), [i]);
-        unwrap!(nb::block!(can.transmit(&tx_frame)));
-        while !can.is_transmitter_idle() {}
-        let rx_frame = unwrap!(nb::block!(can.receive()));
+        can.write(&tx_frame).await;
+        let (_, rx_frame) = can.read().await.unwrap();
         info!("loopback frame {=u8}", unwrap!(rx_frame.data())[0]);
         i += 1;
     }

examples/stm32f7/src/bin/can.rs

@@ -0,0 +1,66 @@
+#![no_std]
+#![no_main]
+#![feature(type_alias_impl_trait)]
+
+use defmt::*;
+use embassy_executor::Spawner;
+use embassy_stm32::bind_interrupts;
+use embassy_stm32::can::bxcan::filter::Mask32;
+use embassy_stm32::can::bxcan::{Fifo, Frame, StandardId};
+use embassy_stm32::can::{
+    Can, CanTx, Rx0InterruptHandler, Rx1InterruptHandler, SceInterruptHandler, TxInterruptHandler,
+};
+use embassy_stm32::gpio::{Input, Pull};
+use embassy_stm32::peripherals::CAN3;
+use {defmt_rtt as _, panic_probe as _};
+
+bind_interrupts!(struct Irqs {
+    CAN3_RX0 => Rx0InterruptHandler<CAN3>;
+    CAN3_RX1 => Rx1InterruptHandler<CAN3>;
+    CAN3_SCE => SceInterruptHandler<CAN3>;
+    CAN3_TX => TxInterruptHandler<CAN3>;
+});
+
+#[embassy_executor::task]
+pub async fn send_can_message(tx: &'static mut CanTx<'static, 'static, CAN3>) {
+    loop {
+        let frame = Frame::new_data(unwrap!(StandardId::new(0 as _)), [0]);
+        tx.write(&frame).await;
+        embassy_time::Timer::after(embassy_time::Duration::from_secs(1)).await;
+    }
+}
+
+#[embassy_executor::main]
+async fn main(spawner: Spawner) {
+    info!("Hello World!");
+
+    let mut p = embassy_stm32::init(Default::default());
+
+    // The next two lines are a workaround for testing without transceiver.
+    // To synchronise to the bus the RX input needs to see a high level.
+    // Use `mem::forget()` to release the borrow on the pin but keep the
+    // pull-up resistor enabled.
+    let rx_pin = Input::new(&mut p.PA15, Pull::Up);
+    core::mem::forget(rx_pin);
+
+    let can: &'static mut Can<'static, CAN3> = static_cell::make_static!(Can::new(p.CAN3, p.PA8, p.PA15, Irqs));
+    can.as_mut()
+        .modify_filters()
+        .enable_bank(0, Fifo::Fifo0, Mask32::accept_all());
+
+    can.as_mut()
+        .modify_config()
+        .set_bit_timing(0x001c0001) // http://www.bittiming.can-wiki.info/
+        .set_loopback(true)
+        .enable();
+
+    let (tx, mut rx) = can.split();
+
+    let tx: &'static mut CanTx<'static, 'static, CAN3> = static_cell::make_static!(tx);
+    spawner.spawn(send_can_message(tx)).unwrap();
+
+    loop {
+        let frame = rx.read().await.unwrap();
+        println!("Received: {:?}", frame);
+    }
+}

tests/stm32/src/bin/can.rs

@@ -43,10 +43,13 @@ async fn main(_spawner: Spawner) {
 
     info!("Configuring can...");
 
-    can.modify_filters().enable_bank(0, Fifo::Fifo0, Mask32::accept_all());
+    can.as_mut()
+        .modify_filters()
+        .enable_bank(0, Fifo::Fifo0, Mask32::accept_all());
 
     can.set_bitrate(1_000_000);
-    can.modify_config()
+    can.as_mut()
+        .modify_config()
         .set_loopback(true) // Receive own frames
         .set_silent(true)
         // .set_bit_timing(0x001c0003)