diff --git a/embassy-stm32/src/can/bxcan.rs b/embassy-stm32/src/can/bxcan.rs index 85f6e99ac..88eef528f 100644 --- a/embassy-stm32/src/can/bxcan.rs +++ b/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 { + _phantom: PhantomData, +} + +impl interrupt::typelevel::Handler for TxInterruptHandler { + 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 { + _phantom: PhantomData, +} + +impl interrupt::typelevel::Handler for Rx0InterruptHandler { + unsafe fn on_interrupt() { + // info!("rx0 irq"); + Can::::receive_fifo(RxFifo::Fifo0); + } +} + +pub struct Rx1InterruptHandler { + _phantom: PhantomData, +} + +impl interrupt::typelevel::Handler for Rx1InterruptHandler { + unsafe fn on_interrupt() { + // info!("rx1 irq"); + Can::::receive_fifo(RxFifo::Fifo1); + } +} + +pub struct SceInterruptHandler { + _phantom: PhantomData, +} + +impl interrupt::typelevel::Handler for SceInterruptHandler { + 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>, } +#[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

+ 'd, rx: impl Peripheral

> + 'd, tx: impl Peripheral

> + 'd, + _irqs: impl interrupt::typelevel::Binding> + + interrupt::typelevel::Binding> + + interrupt::typelevel::Binding> + + interrupt::typelevel::Binding> + + '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}; - /// 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_disabled( - peri: impl Peripheral

+ 'd, - rx: impl Peripheral

> + 'd, - tx: impl Peripheral

> + 'd, - ) -> Self { - into_ref!(peri, rx, tx); + 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); + }); + } + + unsafe { + T::TXInterrupt::unpend(); + T::TXInterrupt::enable(); + + T::RX0Interrupt::unpend(); + T::RX0Interrupt::enable(); + + 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(); - T::reset(); + let can = bxcan::Can::builder(BxcanInstance(peri)).leave_disabled(); + Self { can } + } - Self { - can: bxcan::Can::builder(BxcanInstance(peri)).leave_disabled(), + 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(); + } + + /// 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 { + 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 { + 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, + } + + 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; +} + +impl IntoBusError for Lec { + fn into_bus_err(self) -> Option { + 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, + } + } +} diff --git a/examples/stm32f4/src/bin/can.rs b/examples/stm32f4/src/bin/can.rs index e8377b9a1..da8955053 100644 --- a/examples/stm32f4/src/bin/can.rs +++ b/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_RX1 => Rx1InterruptHandler; + CAN1_SCE => SceInterruptHandler; + CAN1_TX => TxInterruptHandler; +}); + #[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()); diff --git a/tests/stm32/Cargo.toml b/tests/stm32/Cargo.toml index 487ef4626..365f631b7 100644 --- a/tests/stm32/Cargo.toml +++ b/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" diff --git a/tests/stm32/src/bin/can.rs b/tests/stm32/src/bin/can.rs new file mode 100644 index 000000000..33d63d546 --- /dev/null +++ b/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_RX1 => Rx1InterruptHandler; + CAN1_SCE => SceInterruptHandler; + CAN1_TX => TxInterruptHandler; +}); + +#[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(); +}