Merge pull request #1501 from xoviat/can

async can

embassy-stm32/src/can/bxcan.rs

@@ -1,22 +1,106 @@
+use core::future::poll_fn;
+use core::marker::PhantomData;
 use core::ops::{Deref, DerefMut};
+use core::task::Poll;
 
 pub use bxcan;
+use bxcan::{Data, ExtendedId, Frame, Id, StandardId};
 use embassy_hal_common::{into_ref, PeripheralRef};
+use futures::FutureExt;
 
 use crate::gpio::sealed::AFType;
+use crate::interrupt::typelevel::Interrupt;
+use crate::pac::can::vals::{Lec, RirIde};
 use crate::rcc::RccPeripheral;
-use crate::{peripherals, Peripheral};
+use crate::time::Hertz;
+use crate::{interrupt, peripherals, Peripheral};
+
+/// Interrupt handler.
+pub struct TxInterruptHandler<T: Instance> {
+    _phantom: PhantomData<T>,
+}
+
+impl<T: Instance> interrupt::typelevel::Handler<T::TXInterrupt> for TxInterruptHandler<T> {
+    unsafe fn on_interrupt() {
+        T::regs().tsr().write(|v| {
+            v.set_rqcp(0, true);
+            v.set_rqcp(1, true);
+            v.set_rqcp(2, true);
+        });
+
+        T::state().tx_waker.wake();
+    }
+}
+
+pub struct Rx0InterruptHandler<T: Instance> {
+    _phantom: PhantomData<T>,
+}
+
+impl<T: Instance> interrupt::typelevel::Handler<T::RX0Interrupt> for Rx0InterruptHandler<T> {
+    unsafe fn on_interrupt() {
+        // info!("rx0 irq");
+        Can::<T>::receive_fifo(RxFifo::Fifo0);
+    }
+}
+
+pub struct Rx1InterruptHandler<T: Instance> {
+    _phantom: PhantomData<T>,
+}
+
+impl<T: Instance> interrupt::typelevel::Handler<T::RX1Interrupt> for Rx1InterruptHandler<T> {
+    unsafe fn on_interrupt() {
+        // info!("rx1 irq");
+        Can::<T>::receive_fifo(RxFifo::Fifo1);
+    }
+}
+
+pub struct SceInterruptHandler<T: Instance> {
+    _phantom: PhantomData<T>,
+}
+
+impl<T: Instance> interrupt::typelevel::Handler<T::SCEInterrupt> for SceInterruptHandler<T> {
+    unsafe fn on_interrupt() {
+        // info!("sce irq");
+        let msr = T::regs().msr();
+        let msr_val = msr.read();
+
+        if msr_val.erri() {
+            msr.modify(|v| v.set_erri(true));
+            T::state().err_waker.wake();
+        }
+    }
+}
 
 pub struct Can<'d, T: Instance> {
     can: bxcan::Can<BxcanInstance<'d, T>>,
 }
 
+#[derive(Debug)]
+pub enum BusError {
+    Stuff,
+    Form,
+    Acknowledge,
+    BitRecessive,
+    BitDominant,
+    Crc,
+    Software,
+    BusOff,
+    BusPassive,
+    BusWarning,
+}
+
 impl<'d, T: Instance> Can<'d, T> {
-    /// Creates a new Bxcan instance, blocking for 11 recessive bits to sync with the CAN bus.
+    /// Creates a new Bxcan instance, keeping the peripheral in sleep mode.
+    /// You must call [Can::enable_non_blocking] to use the peripheral.
     pub fn new(
         peri: impl Peripheral<P = T> + 'd,
         rx: impl Peripheral<P = impl RxPin<T>> + 'd,
         tx: impl Peripheral<P = impl TxPin<T>> + 'd,
+        _irqs: impl interrupt::typelevel::Binding<T::TXInterrupt, TxInterruptHandler<T>>
+            + interrupt::typelevel::Binding<T::RX0Interrupt, Rx0InterruptHandler<T>>
+            + interrupt::typelevel::Binding<T::RX1Interrupt, Rx1InterruptHandler<T>>
+            + interrupt::typelevel::Binding<T::SCEInterrupt, SceInterruptHandler<T>>
+            + 'd,
     ) -> Self {
         into_ref!(peri, rx, tx);
 
@@ -26,30 +110,242 @@ impl<'d, T: Instance> Can<'d, T> {
         T::enable();
         T::reset();
 
-        Self {
+        {
-            can: bxcan::Can::builder(BxcanInstance(peri)).enable(),
+            use crate::pac::can::vals::{Errie, Fmpie, Tmeie};
-        }
+
+            T::regs().ier().write(|w| {
+                // TODO: fix metapac
+
+                w.set_errie(Errie(1));
+                w.set_fmpie(0, Fmpie(1));
+                w.set_fmpie(1, Fmpie(1));
+                w.set_tmeie(Tmeie(1));
+            });
+
+            T::regs().mcr().write(|w| {
+                // Enable timestamps on rx messages
+
+                w.set_ttcm(true);
+            });
         }
 
-    /// Creates a new Bxcan instance, keeping the peripheral in sleep mode.
+        unsafe {
-    /// You must call [Can::enable_non_blocking] to use the peripheral.
+            T::TXInterrupt::unpend();
-    pub fn new_disabled(
+            T::TXInterrupt::enable();
-        peri: impl Peripheral<P = T> + 'd,
+
-        rx: impl Peripheral<P = impl RxPin<T>> + 'd,
+            T::RX0Interrupt::unpend();
-        tx: impl Peripheral<P = impl TxPin<T>> + 'd,
+            T::RX0Interrupt::enable();
-    ) -> Self {
+
-        into_ref!(peri, rx, tx);
+            T::RX1Interrupt::unpend();
+            T::RX1Interrupt::enable();
+
+            T::SCEInterrupt::unpend();
+            T::SCEInterrupt::enable();
+        }
 
         rx.set_as_af(rx.af_num(), AFType::Input);
         tx.set_as_af(tx.af_num(), AFType::OutputPushPull);
 
-        T::enable();
+        let can = bxcan::Can::builder(BxcanInstance(peri)).leave_disabled();
-        T::reset();
+        Self { can }
+    }
 
-        Self {
+    pub fn set_bitrate(&mut self, bitrate: u32) {
-            can: bxcan::Can::builder(BxcanInstance(peri)).leave_disabled(),
+        let bit_timing = Self::calc_bxcan_timings(T::frequency(), bitrate).unwrap();
+        self.can.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) {
+                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;
+    }
+
+    /// Returns a tuple of the time the message was received and the message frame
+    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
+    }
+
+    unsafe fn receive_fifo(fifo: RxFifo) {
+        let state = T::state();
+        let regs = T::regs();
+        let fifo_idx = match fifo {
+            RxFifo::Fifo0 => 0usize,
+            RxFifo::Fifo1 => 1usize,
+        };
+        let rfr = regs.rfr(fifo_idx);
+        let fifo = regs.rx(fifo_idx);
+
+        loop {
+            // If there are no pending messages, there is nothing to do
+            if rfr.read().fmp() == 0 {
+                return;
+            }
+
+            let rir = fifo.rir().read();
+            let id = if rir.ide() == RirIde::STANDARD {
+                Id::from(StandardId::new_unchecked(rir.stid()))
+            } else {
+                let stid = (rir.stid() & 0x7FF) as u32;
+                let exid = rir.exid() & 0x3FFFF;
+                let id = (stid << 18) | (exid as u32);
+                Id::from(ExtendedId::new_unchecked(id))
+            };
+            let data_len = fifo.rdtr().read().dlc() as usize;
+            let mut data: [u8; 8] = [0; 8];
+            data[0..4].copy_from_slice(&fifo.rdlr().read().0.to_ne_bytes());
+            data[4..8].copy_from_slice(&fifo.rdhr().read().0.to_ne_bytes());
+
+            let time = fifo.rdtr().read().time();
+            let frame = Frame::new_data(id, Data::new(&data[0..data_len]).unwrap());
+
+            rfr.modify(|v| v.set_rfom(true));
+
+            /*
+                NOTE: consensus was reached that if rx_queue is full, packets should be dropped
+            */
+            let _ = state.rx_queue.try_send((time, frame));
         }
     }
+
+    pub const fn calc_bxcan_timings(periph_clock: Hertz, can_bitrate: u32) -> Option<u32> {
+        const BS1_MAX: u8 = 16;
+        const BS2_MAX: u8 = 8;
+        const MAX_SAMPLE_POINT_PERMILL: u16 = 900;
+
+        let periph_clock = periph_clock.0;
+
+        if can_bitrate < 1000 {
+            return None;
+        }
+
+        // Ref. "Automatic Baudrate Detection in CANopen Networks", U. Koppe, MicroControl GmbH & Co. KG
+        //      CAN in Automation, 2003
+        //
+        // According to the source, optimal quanta per bit are:
+        //   Bitrate        Optimal Maximum
+        //   1000 kbps      8       10
+        //   500  kbps      16      17
+        //   250  kbps      16      17
+        //   125  kbps      16      17
+        let max_quanta_per_bit: u8 = if can_bitrate >= 1_000_000 { 10 } else { 17 };
+
+        // Computing (prescaler * BS):
+        //   BITRATE = 1 / (PRESCALER * (1 / PCLK) * (1 + BS1 + BS2))       -- See the Reference Manual
+        //   BITRATE = PCLK / (PRESCALER * (1 + BS1 + BS2))                 -- Simplified
+        // let:
+        //   BS = 1 + BS1 + BS2                                             -- Number of time quanta per bit
+        //   PRESCALER_BS = PRESCALER * BS
+        // ==>
+        //   PRESCALER_BS = PCLK / BITRATE
+        let prescaler_bs = periph_clock / can_bitrate;
+
+        // Searching for such prescaler value so that the number of quanta per bit is highest.
+        let mut bs1_bs2_sum = max_quanta_per_bit - 1;
+        while (prescaler_bs % (1 + bs1_bs2_sum) as u32) != 0 {
+            if bs1_bs2_sum <= 2 {
+                return None; // No solution
+            }
+            bs1_bs2_sum -= 1;
+        }
+
+        let prescaler = prescaler_bs / (1 + bs1_bs2_sum) as u32;
+        if (prescaler < 1) || (prescaler > 1024) {
+            return None; // No solution
+        }
+
+        // Now we have a constraint: (BS1 + BS2) == bs1_bs2_sum.
+        // We need to find such values so that the sample point is as close as possible to the optimal value,
+        // which is 87.5%, which is 7/8.
+        //
+        //   Solve[(1 + bs1)/(1 + bs1 + bs2) == 7/8, bs2]  (* Where 7/8 is 0.875, the recommended sample point location *)
+        //   {{bs2 -> (1 + bs1)/7}}
+        //
+        // Hence:
+        //   bs2 = (1 + bs1) / 7
+        //   bs1 = (7 * bs1_bs2_sum - 1) / 8
+        //
+        // Sample point location can be computed as follows:
+        //   Sample point location = (1 + bs1) / (1 + bs1 + bs2)
+        //
+        // Since the optimal solution is so close to the maximum, we prepare two solutions, and then pick the best one:
+        //   - With rounding to nearest
+        //   - With rounding to zero
+        let mut bs1 = ((7 * bs1_bs2_sum - 1) + 4) / 8; // Trying rounding to nearest first
+        let mut bs2 = bs1_bs2_sum - bs1;
+        core::assert!(bs1_bs2_sum > bs1);
+
+        let sample_point_permill = 1000 * ((1 + bs1) / (1 + bs1 + bs2)) as u16;
+        if sample_point_permill > MAX_SAMPLE_POINT_PERMILL {
+            // Nope, too far; now rounding to zero
+            bs1 = (7 * bs1_bs2_sum - 1) / 8;
+            bs2 = bs1_bs2_sum - bs1;
+        }
+
+        // Check is BS1 and BS2 are in range
+        if (bs1 < 1) || (bs1 > BS1_MAX) || (bs2 < 1) || (bs2 > BS2_MAX) {
+            return None;
+        }
+
+        // Check if final bitrate matches the requested
+        if can_bitrate != (periph_clock / (prescaler * (1 + bs1 + bs2) as u32)) {
+            return None;
+        }
+
+        // One is recommended by DS-015, CANOpen, and DeviceNet
+        let sjw = 1;
+
+        // Pack into BTR register values
+        Some((sjw - 1) << 24 | (bs1 as u32 - 1) << 16 | (bs2 as u32 - 1) << 20 | (prescaler as u32 - 1))
+    }
+}
+
+enum RxFifo {
+    Fifo0,
+    Fifo1,
 }
 
 impl<'d, T: Instance> Drop for Can<'d, T> {
@@ -76,14 +372,52 @@ impl<'d, T: Instance> DerefMut for Can<'d, T> {
 }
 
 pub(crate) mod sealed {
+    use embassy_sync::blocking_mutex::raw::CriticalSectionRawMutex;
+    use embassy_sync::channel::Channel;
+    use embassy_sync::waitqueue::AtomicWaker;
+
+    pub struct State {
+        pub tx_waker: AtomicWaker,
+        pub err_waker: AtomicWaker,
+        pub rx_queue: Channel<CriticalSectionRawMutex, (u16, bxcan::Frame), 32>,
+    }
+
+    impl State {
+        pub const fn new() -> Self {
+            Self {
+                tx_waker: AtomicWaker::new(),
+                err_waker: AtomicWaker::new(),
+                rx_queue: Channel::new(),
+            }
+        }
+    }
+
     pub trait Instance {
         const REGISTERS: *mut bxcan::RegisterBlock;
 
         fn regs() -> &'static crate::pac::can::Can;
+        fn state() -> &'static State;
     }
 }
 
-pub trait Instance: sealed::Instance + RccPeripheral {}
+pub trait TXInstance {
+    type TXInterrupt: crate::interrupt::typelevel::Interrupt;
+}
+
+pub trait RX0Instance {
+    type RX0Interrupt: crate::interrupt::typelevel::Interrupt;
+}
+
+pub trait RX1Instance {
+    type RX1Interrupt: crate::interrupt::typelevel::Interrupt;
+}
+
+pub trait SCEInstance {
+    type SCEInterrupt: crate::interrupt::typelevel::Interrupt;
+}
+
+pub trait InterruptableInstance: TXInstance + RX0Instance + RX1Instance + SCEInstance {}
+pub trait Instance: sealed::Instance + RccPeripheral + InterruptableInstance + 'static {}
 
 pub struct BxcanInstance<'a, T>(PeripheralRef<'a, T>);
 
@@ -99,10 +433,39 @@ foreach_peripheral!(
             fn regs() -> &'static crate::pac::can::Can {
                 &crate::pac::$inst
             }
+
+            fn state() -> &'static sealed::State {
+                static STATE: sealed::State = sealed::State::new();
+                &STATE
+            }
         }
 
         impl Instance for peripherals::$inst {}
 
+        foreach_interrupt!(
+            ($inst,can,CAN,TX,$irq:ident) => {
+                impl TXInstance for peripherals::$inst {
+                    type TXInterrupt = crate::interrupt::typelevel::$irq;
+                }
+            };
+            ($inst,can,CAN,RX0,$irq:ident) => {
+                impl RX0Instance for peripherals::$inst {
+                    type RX0Interrupt = crate::interrupt::typelevel::$irq;
+                }
+            };
+            ($inst,can,CAN,RX1,$irq:ident) => {
+                impl RX1Instance for peripherals::$inst {
+                    type RX1Interrupt = crate::interrupt::typelevel::$irq;
+                }
+            };
+            ($inst,can,CAN,SCE,$irq:ident) => {
+                impl SCEInstance for peripherals::$inst {
+                    type SCEInterrupt = crate::interrupt::typelevel::$irq;
+                }
+            };
+        );
+
+        impl InterruptableInstance for peripherals::$inst {}
     };
 );
 
@@ -143,3 +506,36 @@ foreach_peripheral!(
 
 pin_trait!(RxPin, Instance);
 pin_trait!(TxPin, Instance);
+
+trait Index {
+    fn index(&self) -> usize;
+}
+
+impl Index for bxcan::Mailbox {
+    fn index(&self) -> usize {
+        match self {
+            bxcan::Mailbox::Mailbox0 => 0,
+            bxcan::Mailbox::Mailbox1 => 1,
+            bxcan::Mailbox::Mailbox2 => 2,
+        }
+    }
+}
+
+trait IntoBusError {
+    fn into_bus_err(self) -> Option<BusError>;
+}
+
+impl IntoBusError for Lec {
+    fn into_bus_err(self) -> Option<BusError> {
+        match self {
+            Lec::STUFF => Some(BusError::Stuff),
+            Lec::FORM => Some(BusError::Form),
+            Lec::ACK => Some(BusError::Acknowledge),
+            Lec::BITRECESSIVE => Some(BusError::BitRecessive),
+            Lec::BITDOMINANT => Some(BusError::BitDominant),
+            Lec::CRC => Some(BusError::Crc),
+            Lec::CUSTOM => Some(BusError::Software),
+            _ => None,
+        }
+    }
+}

examples/stm32f4/src/bin/can.rs

@@ -4,12 +4,21 @@
 
 use cortex_m_rt::entry;
 use defmt::*;
+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;
+use embassy_stm32::can::{Can, Rx0InterruptHandler, Rx1InterruptHandler, SceInterruptHandler, TxInterruptHandler};
 use embassy_stm32::gpio::{Input, Pull};
+use embassy_stm32::peripherals::CAN1;
 use {defmt_rtt as _, panic_probe as _};
 
+bind_interrupts!(struct Irqs {
+    CAN1_RX0 => Rx0InterruptHandler<CAN1>;
+    CAN1_RX1 => Rx1InterruptHandler<CAN1>;
+    CAN1_SCE => SceInterruptHandler<CAN1>;
+    CAN1_TX => TxInterruptHandler<CAN1>;
+});
+
 #[entry]
 fn main() -> ! {
     info!("Hello World!");
@@ -23,7 +32,7 @@ fn main() -> ! {
     let rx_pin = Input::new(&mut p.PA11, Pull::Up);
     core::mem::forget(rx_pin);
 
-    let mut can = Can::new(p.CAN1, p.PA11, p.PA12);
+    let mut can = Can::new(p.CAN1, p.PA11, p.PA12, Irqs);
 
     can.modify_filters().enable_bank(0, Fifo::Fifo0, Mask32::accept_all());
 

tests/stm32/Cargo.toml

@@ -7,7 +7,7 @@ autobins = false
 
 [features]
 stm32f103c8 = ["embassy-stm32/stm32f103c8", "not-gpdma"]     # Blue Pill
-stm32f429zi = ["embassy-stm32/stm32f429zi", "chrono", "not-gpdma"]     # Nucleo "sdmmc"
+stm32f429zi = ["embassy-stm32/stm32f429zi", "chrono", "can", "not-gpdma"]     # Nucleo "sdmmc"
 stm32g071rb = ["embassy-stm32/stm32g071rb", "not-gpdma"]     # Nucleo
 stm32c031c6 = ["embassy-stm32/stm32c031c6", "not-gpdma"]     # Nucleo
 stm32g491re = ["embassy-stm32/stm32g491re", "not-gpdma"]     # Nucleo
@@ -18,6 +18,7 @@ stm32u585ai = ["embassy-stm32/stm32u585ai"]     # IoT board
 
 sdmmc = []
 chrono = ["embassy-stm32/chrono", "dep:chrono"]
+can = []
 ble = ["dep:embassy-stm32-wpan"]
 not-gpdma = []
 
@@ -52,6 +53,11 @@ name = "tl_mbox"
 path = "src/bin/tl_mbox.rs"
 required-features = [ "ble",]
 
+[[bin]]
+name = "can"
+path = "src/bin/can.rs"
+required-features = [ "can",]
+
 [[bin]]
 name = "gpio"
 path = "src/bin/gpio.rs"

tests/stm32/src/bin/can.rs

@@ -0,0 +1,78 @@
+#![no_std]
+#![no_main]
+#![feature(type_alias_impl_trait)]
+
+// required-features: can
+
+#[path = "../common.rs"]
+mod common;
+use common::*;
+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, Rx0InterruptHandler, Rx1InterruptHandler, SceInterruptHandler, TxInterruptHandler};
+use embassy_stm32::gpio::{Input, Pull};
+use embassy_stm32::peripherals::CAN1;
+use {defmt_rtt as _, panic_probe as _};
+
+bind_interrupts!(struct Irqs {
+    CAN1_RX0 => Rx0InterruptHandler<CAN1>;
+    CAN1_RX1 => Rx1InterruptHandler<CAN1>;
+    CAN1_SCE => SceInterruptHandler<CAN1>;
+    CAN1_TX => TxInterruptHandler<CAN1>;
+});
+
+#[embassy_executor::main]
+async fn main(_spawner: Spawner) {
+    let mut p = embassy_stm32::init(config());
+    info!("Hello World!");
+
+    // HW is connected as follows:
+    // PB13 -> PD0
+    // PB12 -> PD1
+
+    // 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.PD0, Pull::Up);
+    core::mem::forget(rx_pin);
+
+    let mut can = Can::new(p.CAN1, p.PD0, p.PD1, Irqs);
+
+    info!("Configuring can...");
+
+    can.modify_filters().enable_bank(0, Fifo::Fifo0, Mask32::accept_all());
+
+    can.set_bitrate(1_000_000);
+    can.modify_config()
+        .set_loopback(true) // Receive own frames
+        .set_silent(true)
+        // .set_bit_timing(0x001c0003)
+        .enable();
+
+    info!("Can configured");
+
+    let mut i: u8 = 0;
+    loop {
+        let tx_frame = Frame::new_data(unwrap!(StandardId::new(i as _)), [i]);
+
+        info!("Transmitting frame...");
+        can.write(&tx_frame).await;
+
+        info!("Receiving frame...");
+        let (time, rx_frame) = can.read().await.unwrap();
+
+        info!("loopback time {}", time);
+        info!("loopback frame {=u8}", rx_frame.data().unwrap()[0]);
+
+        i += 1;
+        if i > 10 {
+            break;
+        }
+    }
+
+    info!("Test OK");
+    cortex_m::asm::bkpt();
+}