Merge commit '8d7abeb06fbe3e19db3cae3f5220725969ecbb81' of https://github.com/Lytehorse/embassy into can

2 files changed, 371 insertions, 4 deletions

diff --git a/embassy-stm32/Cargo.toml b/embassy-stm32/Cargo.toml
index 4e29bb32f..5d4b26a36 100644
--- a/embassy-stm32/Cargo.toml
+++ b/embassy-stm32/Cargo.toml
@@ -69,6 +69,7 @@ cfg-if = "1.0.0"
 embedded-io = { version = "0.4.0", features = ["async"], optional = true }
 chrono = { version = "^0.4", default-features = false, optional = true}
 bit_field = "0.10.2"
+heapless = { version = "0.7.5", default-features = false }
 
 [dev-dependencies]
 critical-section = { version = "1.1", features = ["std"] }
diff --git a/embassy-stm32/src/can/bxcan.rs b/embassy-stm32/src/can/bxcan.rs
index bd92b35a0..734efdc02 100644
--- a/embassy-stm32/src/can/bxcan.rs
+++ b/embassy-stm32/src/can/bxcan.rs
@@ -1,16 +1,41 @@
+use core::future::poll_fn;
 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 crate::gpio::sealed::AFType;
+use crate::interrupt::InterruptExt;
+use crate::pac::can::vals::{Lec, RirIde};
 use crate::rcc::RccPeripheral;
+use crate::time::Hertz;
 use crate::{peripherals, Peripheral};
 
 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,
+}
+
+pub enum FrameOrError {
+    Frame(Frame),
+    Error(BusError),
+}
+
 impl<'d, T: Instance> Can<'d, T> {
     /// Creates a new Bxcan instance, blocking for 11 recessive bits to sync with the CAN bus.
     pub fn new(
@@ -39,8 +64,12 @@ impl<'d, T: Instance> Can<'d, T> {
         peri: impl Peripheral<P = T> + 'd,
         rx: impl Peripheral<P = impl RxPin<T>> + 'd,
         tx: impl Peripheral<P = impl TxPin<T>> + 'd,
+        tx_irq: impl Peripheral<P = T::TXInterrupt> + 'd,
+        rx0_irq: impl Peripheral<P = T::RX0Interrupt> + 'd,
+        rx1_irq: impl Peripheral<P = T::RX1Interrupt> + 'd,
+        sce_irq: impl Peripheral<P = T::SCEInterrupt> + 'd,
     ) -> Self {
-        into_ref!(peri, rx, tx);
+        into_ref!(peri, rx, tx, tx_irq, rx0_irq, rx1_irq, sce_irq);
 
         unsafe {
             rx.set_as_af(rx.af_num(), AFType::Input);
@@ -50,10 +79,246 @@ impl<'d, T: Instance> Can<'d, T> {
         T::enable();
         T::reset();
 
-        Self {
-            can: bxcan::Can::builder(BxcanInstance(peri)).leave_disabled(),
+        tx_irq.unpend();
+        tx_irq.set_handler(Self::tx_interrupt);
+        tx_irq.enable();
+
+        rx0_irq.unpend();
+        rx0_irq.set_handler(Self::rx0_interrupt);
+        rx0_irq.enable();
+
+        rx1_irq.unpend();
+        rx1_irq.set_handler(Self::rx1_interrupt);
+        rx1_irq.enable();
+
+        sce_irq.unpend();
+        sce_irq.set_handler(Self::sce_interrupt);
+        sce_irq.enable();
+
+        let can = bxcan::Can::builder(BxcanInstance(peri)).leave_disabled();
+        Self { can }
+    }
+
+    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();
+    }
+
+    pub async fn transmit(&mut self, frame: &Frame) {
+        let tx_status = self.queue_transmit(frame).await;
+        self.wait_transission(tx_status.mailbox()).await;
+    }
+
+    async fn queue_transmit(&mut self, frame: &Frame) -> bxcan::TransmitStatus {
+        poll_fn(|cx| {
+            if let Ok(status) = self.can.transmit(frame) {
+                return Poll::Ready(status);
+            }
+            T::state().tx_waker.register(cx.waker());
+            Poll::Pending
+        })
+        .await
+    }
+
+    async fn wait_transission(&self, mb: bxcan::Mailbox) {
+        poll_fn(|cx| unsafe {
+            if T::regs().tsr().read().tme(mb.index()) {
+                return Poll::Ready(());
+            }
+            T::state().tx_waker.register(cx.waker());
+            Poll::Pending
+        })
+        .await;
+    }
+
+    pub async fn receive_frame_or_error(&mut self) -> FrameOrError {
+        poll_fn(|cx| {
+            if let Some(frame) = T::state().rx_queue.dequeue() {
+                return Poll::Ready(FrameOrError::Frame(frame));
+            } else if let Some(err) = self.curr_error() {
+                return Poll::Ready(FrameOrError::Error(err));
+            }
+            T::state().rx_waker.register(cx.waker());
+            T::state().err_waker.register(cx.waker());
+            Poll::Pending
+        })
+        .await
+    }
+
+    fn curr_error(&self) -> Option<BusError> {
+        let err = unsafe { 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 sce_interrupt(_: *mut ()) {
+        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();
+            return;
+        }
+    }
+
+    unsafe fn tx_interrupt(_: *mut ()) {
+        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();
+    }
+
+    unsafe fn rx0_interrupt(_: *mut ()) {
+        Self::receive_fifo(RxFifo::Fifo0);
+    }
+
+    unsafe fn rx1_interrupt(_: *mut ()) {
+        Self::receive_fifo(RxFifo::Fifi1);
+    }
+
+    unsafe fn receive_fifo(fifo: RxFifo) {
+        let state = T::state();
+        let regs = T::regs();
+        let fifo_idx = match fifo {
+            RxFifo::Fifo0 => 0usize,
+            RxFifo::Fifi1 => 1usize,
+        };
+        let rfr = regs.rfr(fifo_idx);
+        let fifo = regs.rx(fifo_idx);
+
+        // 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 {
+            Id::from(ExtendedId::new_unchecked(rir.exid()))
+        };
+        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 frame = Frame::new_data(id, Data::new(&data[0..data_len]).unwrap());
+
+        rfr.modify(|v| v.set_rfom(true));
+
+        match state.rx_queue.enqueue(frame) {
+            Ok(_) => {}
+            Err(_) => defmt::error!("RX queue overflow"),
+        }
+        state.rx_waker.wake();
+    }
+
+    pub 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;
+        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,
+    Fifi1,
 }
 
 impl<'d, T: Instance> Drop for Can<'d, T> {
@@ -80,14 +345,53 @@ impl<'d, T: Instance> DerefMut for Can<'d, T> {
 }
 
 pub(crate) mod sealed {
+    use embassy_sync::waitqueue::AtomicWaker;
+    use heapless::mpmc::Q8;
+
+    pub struct State {
+        pub tx_waker: AtomicWaker,
+        pub rx_waker: AtomicWaker,
+        pub err_waker: AtomicWaker,
+        pub rx_queue: Q8<bxcan::Frame>,
+    }
+
+    impl State {
+        pub const fn new() -> Self {
+            Self {
+                tx_waker: AtomicWaker::new(),
+                rx_waker: AtomicWaker::new(),
+                err_waker: AtomicWaker::new(),
+                rx_queue: Q8::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::Interrupt;
+}
+
+pub trait RX0Instance {
+    type RX0Interrupt: crate::interrupt::Interrupt;
+}
+
+pub trait RX1Instance {
+    type RX1Interrupt: crate::interrupt::Interrupt;
+}
+
+pub trait SCEInstance {
+    type SCEInterrupt: crate::interrupt::Interrupt;
+}
+
+pub trait InterruptableInstance: TXInstance + RX0Instance + RX1Instance + SCEInstance {}
+pub trait Instance: sealed::Instance + RccPeripheral + InterruptableInstance + 'static {}
 
 pub struct BxcanInstance<'a, T>(PeripheralRef<'a, T>);
 
@@ -103,10 +407,39 @@ 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::$inst {
+                    type TXInterrupt = crate::interrupt::$irq;
+                }
+            };
+            ($inst,can,CAN,RX0,$irq:ident) => {
+                impl RX0Instance for peripherals::$inst {
+                    type RX0Interrupt = crate::interrupt::$irq;
+                }
+            };
+            ($inst,can,CAN,RX1,$irq:ident) => {
+                impl RX1Instance for peripherals::$inst {
+                    type RX1Interrupt = crate::interrupt::$irq;
+                }
+            };
+            ($inst,can,CAN,SCE,$irq:ident) => {
+                impl SCEInstance for peripherals::$inst {
+                    type SCEInterrupt = crate::interrupt::$irq;
+                }
+            };
+        );
+
+        impl InterruptableInstance for peripherals::$inst {}
     };
 );
 
@@ -147,3 +480,36 @@ 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,
+        }
+    }
+}