Implementation of CAN bus drivers

Cargo.toml

@@ -16,6 +16,7 @@ nb = "0.1.2"
 void = { version = "1.0.2", default-features = false }
 cast = { version = "0.2.3", default-features = false }
 vcell = "0.1.2"
+embedded-can = "0.3.0"
 
 [dependencies.embedded-hal]
 version = "0.2.3"

src/afio.rs

@@ -119,9 +119,11 @@ macro_rules! remap {
 }
 
 remap! {
+    CAN0 => (can0_remap, u8),
+    CAN1 => (can1_remap, bool),
     I2C0 => (i2c0_remap, bool),
     SPI0 => (spi0_remap, bool),
-    SPI2 => (spi2_remap, bool),
+    SPI2 => (spi2_remap, bool),    
     USART0 => (usart0_remap, bool),
     USART1 => (usart1_remap, bool),
     USART2 => (usart2_remap, u8),

src/can.rs

@@ -0,0 +1,271 @@
+//! # Controller area network controller
+
+use nb;
+
+pub use crate::hal_can::{Id, Frame as FrameTrait,Can as CanTrait};
+use crate::pac::{can0, CAN0, CAN1};
+use crate::gpio::gpioa::{PA11, PA12};
+use crate::gpio::gpiob::{PB5, PB6, PB8, PB9, PB12, PB13};
+use crate::gpio::gpiod::{PD0, PD1};
+use crate::gpio::{Alternate, Floating, Input, PushPull};
+use crate::rcu::{Rcu, Enable, Reset, BaseFrequency};
+use crate::time::Hertz;
+use crate::afio::{Afio, Remap};
+use core::{convert::TryInto, ops::Deref};
+
+pub struct Frame{
+}
+
+impl FrameTrait for Frame {
+    /// Creates a new frame.
+    /// Returns an error when the data slice is too long.
+    fn new(id: impl Into<Id>, data: &[u8]) -> Result<Self, ()>{
+        unimplemented!()
+    }
+
+    /// Creates a new remote frame (RTR bit set).
+    /// Returns an error when the data length code (DLC) is not valid.
+    fn new_remote(id: impl Into<Id>, dlc: usize) -> Result<Self, ()>{
+        unimplemented!()
+    }
+
+    /// Returns true if this frame is a extended frame.
+    fn is_extended(&self) -> bool{
+        unimplemented!()
+    }
+
+
+    /// Returns true if this frame is a remote frame.
+    fn is_remote_frame(&self) -> bool{
+        unimplemented!()
+    }
+
+    /// Returns the frame identifier.
+    fn id(&self) -> Id{
+        unimplemented!()
+    }
+
+    /// Returns the data length code (DLC) which is in the range 0..8.
+    ///
+    /// For data frames the DLC value always matches the length of the data.
+    /// Remote frames do not carry any data, yet the DLC can be greater than 0.
+    fn dlc(&self) -> usize{
+        unimplemented!()
+    }
+
+    /// Returns the frame data (0..8 bytes in length).
+    fn data(&self) -> &[u8]{
+        unimplemented!()
+    }
+}
+
+/// Can error
+#[derive(Debug)]
+pub enum Error {
+    /// Overrun occurred
+    Overrun,
+    /// Mode fault occurred
+    ModeFault,
+    /// CRC error
+    Crc,
+    #[doc(hidden)]
+    _Extensible,
+}
+
+pub enum CanMode{
+    Normal = 0b00,
+    Silent = 0b10,
+    Loopback = 0b01,
+    SilentLoopback = 0b11
+}
+
+#[derive(Clone)]
+pub struct TimeQuantaConfiguration{
+    pub sync: u8,
+    pub propagandation: u8,
+    pub before_sample: u8,
+    pub after_sample: u8
+}
+
+impl TimeQuantaConfiguration{
+    fn sum(&self) -> u32{
+        (self.sync + self.propagandation + self.before_sample + self.after_sample) as u32
+    }
+    fn bs1(&self) -> u8 {
+        self.propagandation + self.before_sample
+    }
+    fn bs2(&self) -> u8 {
+        self.after_sample
+    }
+}
+
+#[doc(hidden)]
+pub trait CanX: Deref<Target = can0::RegisterBlock> {}
+impl CanX for CAN0 {}
+impl CanX for CAN1 {}
+
+pub trait Pins<CAN> {
+    type Variant;
+    const REMAP: Self::Variant;
+}
+
+impl Pins<CAN0>
+    for (
+        PA11<Input<Floating>>,
+        PA12<Alternate<PushPull>>,
+    )
+{
+    type Variant = u8;
+    const REMAP: u8 = 0b00;
+}
+impl Pins<CAN0>
+    for (
+        PB8<Input<Floating>>,
+        PB9<Alternate<PushPull>>,
+    )
+{
+    type Variant = u8;
+    const REMAP: u8 = 0b10;
+}
+impl Pins<CAN0>
+    for (
+        PD0<Input<Floating>>,
+        PD1<Alternate<PushPull>>,
+    )
+{
+    type Variant = u8;
+    const REMAP: u8 = 0b11;
+}
+
+impl Pins<CAN1>
+    for (
+        PB12<Input<Floating>>,
+        PB13<Alternate<PushPull>>,
+    )
+{
+    type Variant = bool;
+    const REMAP: bool = false;
+}
+impl Pins<CAN1>
+    for (
+        PB5<Input<Floating>>,
+        PB6<Alternate<PushPull>>,
+    )
+{
+    type Variant = bool;
+    const REMAP: bool = true;
+}
+
+pub struct Can<CAN, PINS> {
+    can: CAN,
+    pins: PINS,
+}
+
+impl<PINS: Pins<CAN0, Variant=u8>> Can<CAN0, PINS> {
+    pub fn can0(
+        can: CAN0,
+        pins: PINS,
+        afio: &mut Afio,
+        tqc : TimeQuantaConfiguration,
+        mode: CanMode,
+        freq: impl Into<Hertz>,
+        rcu: &mut Rcu
+    ) -> Self
+    {
+        CAN0::remap(afio, PINS::REMAP);
+        Can::new(can, pins, tqc, mode,freq, rcu)
+    }
+}
+
+impl<PINS: Pins<CAN1, Variant=bool>> Can<CAN1, PINS> {
+    pub fn can1(
+        can: CAN1,
+        pins: PINS,
+        afio: &mut Afio,
+        tqc : TimeQuantaConfiguration,
+        mode: CanMode,
+        freq: impl Into<Hertz>,
+        rcu: &mut Rcu
+    ) -> Self
+    {
+        CAN1::remap(afio, PINS::REMAP);
+        Can::new(can, pins, tqc, mode, freq, rcu)
+    }
+}
+
+
+impl<CAN, PINS> Can<CAN, PINS> where CAN: CanX
+{
+    const MAX_PSC : u16 = 0b111111111;
+    fn new(
+        can: CAN,
+        pins: PINS,
+        tqc : TimeQuantaConfiguration,
+        mode: CanMode,
+        freq: impl Into<Hertz>,
+        rcu: &mut Rcu
+    ) -> Self where CAN: Enable + Reset + BaseFrequency {
+
+        let baudpsc:u16= (
+            CAN::base_frequency(rcu).0 / (freq.into().0  * tqc.sum() )
+        ).try_into().unwrap_or(Self::MAX_PSC);
+        let baudpsc:u16 = if baudpsc > Self::MAX_PSC {
+            Self::MAX_PSC
+        } else if baudpsc == 0 {
+            unreachable!();
+        } else{
+            baudpsc
+        };
+
+        CAN::enable(rcu);
+        CAN::reset(rcu);
+        can.bt.write(|w| unsafe{w
+            .baudpsc().bits(baudpsc)
+            .scmod().bit(match mode {
+                CanMode::Silent | CanMode::SilentLoopback => {true},
+                _ => {false},
+            })
+            .lcmod().bit(match mode {
+                CanMode::Loopback | CanMode::SilentLoopback => {true},
+                _ => {false},
+            })
+            .sjw().bits(tqc.sync)
+            .bs1().bits(tqc.bs1())
+            .bs2().bits(tqc.bs2())
+        });
+        Can{can, pins}
+    }
+}
+
+
+/// A CAN interface that is able to transmit and receive frames.
+impl<CAN, PINS> CanTrait for Can<CAN, PINS> {
+    /// Associated frame type.
+    type Frame = Frame;
+
+    /// Associated error type.
+    type Error = Error;
+
+    /// Puts a frame in the transmit buffer to be sent on the bus.
+    ///
+    /// If the transmit buffer is full, this function will try to replace a pending
+    /// lower priority frame and return the frame that was replaced.
+    /// Returns `Err(WouldBlock)` if the transmit buffer is full and no frame can be
+    /// replaced.
+    ///
+    /// # Notes for implementers
+    ///
+    /// * Frames of equal identifier shall be transmited in FIFO fashion when more
+    ///   than one transmit buffer is available.
+    /// * When replacing pending frames make sure the frame is not in the process of
+    ///   being send to the bus.
+    fn try_transmit(&mut self, frame: &Self::Frame) 
+        -> nb::Result<Option<Self::Frame>, Self::Error>{
+            unimplemented!()
+    }
+
+    /// Returns a received frame if available.
+    fn try_receive(&mut self) -> nb::Result<Self::Frame, Self::Error>{
+        unimplemented!()
+    }
+}

src/lib.rs

@@ -8,9 +8,11 @@
 pub use gd32vf103_pac as pac;
 
 use embedded_hal as hal;
+use embedded_can as hal_can;
 
 pub mod afio;
 pub mod backup_domain;
+pub mod can;
 pub mod delay;
 pub mod eclic;
 pub mod exmc;

src/rcu.rs

@@ -285,6 +285,8 @@ base_freq! {
     SPI0 => pclk2,
     SPI1 => pclk1,
     SPI2 => pclk1,
+    CAN0 => pclk1,
+    CAN1 => pclk1,
     TIMER0 => timer0,
     TIMER1 => timerx,
     TIMER2 => timerx,