stm32: add draft spi trait (#130)

3 files changed, 481 insertions, 1 deletions

diff --git a/embassy-stm32/src/f4/mod.rs b/embassy-stm32/src/f4/mod.rs
index b1fc0cf1d..9edde82ca 100644
--- a/embassy-stm32/src/f4/mod.rs
+++ b/embassy-stm32/src/f4/mod.rs
@@ -1 +1,2 @@
 pub mod serial;
+pub mod spi;
diff --git a/embassy-stm32/src/f4/spi.rs b/embassy-stm32/src/f4/spi.rs
new file mode 100644
index 000000000..bc73611fd
--- /dev/null
+++ b/embassy-stm32/src/f4/spi.rs
@@ -0,0 +1,479 @@
+//! Async SPI
+
+use embassy::time;
+
+use core::{future::Future, marker::PhantomData, mem, ops::Deref, pin::Pin, ptr};
+use embassy::{interrupt::Interrupt, traits::spi::FullDuplex, util::InterruptFuture};
+use nb;
+
+pub use crate::hal::spi::{Mode, Phase, Polarity};
+use crate::hal::{
+    bb, dma,
+    dma::config::DmaConfig,
+    dma::traits::{Channel, DMASet, PeriAddress, Stream},
+    dma::{MemoryToPeripheral, PeripheralToMemory, Transfer},
+    rcc::Clocks,
+    spi::Pins,
+    time::Hertz,
+};
+use crate::interrupt;
+use crate::pac;
+use futures::future;
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
+#[non_exhaustive]
+pub enum Error {
+    TxBufferTooLong,
+    RxBufferTooLong,
+    Overrun,
+    ModeFault,
+    Crc,
+}
+
+fn read_sr<T: Instance>(spi: &T) -> nb::Result<u8, Error> {
+    let sr = spi.sr.read();
+    Err(if sr.ovr().bit_is_set() {
+        nb::Error::Other(Error::Overrun)
+    } else if sr.modf().bit_is_set() {
+        nb::Error::Other(Error::ModeFault)
+    } else if sr.crcerr().bit_is_set() {
+        nb::Error::Other(Error::Crc)
+    } else if sr.rxne().bit_is_set() {
+        // NOTE(read_volatile) read only 1 byte (the svd2rust API only allows
+        // reading a half-word)
+        return Ok(unsafe { ptr::read_volatile(&spi.dr as *const _ as *const u8) });
+    } else {
+        nb::Error::WouldBlock
+    })
+}
+
+fn write_sr<T: Instance>(spi: &T, byte: u8) -> nb::Result<(), Error> {
+    let sr = spi.sr.read();
+    Err(if sr.ovr().bit_is_set() {
+        // Read from the DR to clear the OVR bit
+        let _ = spi.dr.read();
+        nb::Error::Other(Error::Overrun)
+    } else if sr.modf().bit_is_set() {
+        // Write to CR1 to clear MODF
+        spi.cr1.modify(|_r, w| w);
+        nb::Error::Other(Error::ModeFault)
+    } else if sr.crcerr().bit_is_set() {
+        // Clear the CRCERR bit
+        spi.sr.modify(|_r, w| {
+            w.crcerr().clear_bit();
+            w
+        });
+        nb::Error::Other(Error::Crc)
+    } else if sr.txe().bit_is_set() {
+        // NOTE(write_volatile) see note above
+        unsafe { ptr::write_volatile(&spi.dr as *const _ as *mut u8, byte) }
+        return Ok(());
+    } else {
+        nb::Error::WouldBlock
+    })
+}
+
+/// Interface to the Serial peripheral
+pub struct Spi<
+    SPI: PeriAddress<MemSize = u8> + WithInterrupt,
+    TSTREAM: Stream + WithInterrupt,
+    RSTREAM: Stream + WithInterrupt,
+    CHANNEL: Channel,
+> {
+    tx_stream: Option<TSTREAM>,
+    rx_stream: Option<RSTREAM>,
+    spi: Option<SPI>,
+    tx_int: TSTREAM::Interrupt,
+    rx_int: RSTREAM::Interrupt,
+    spi_int: SPI::Interrupt,
+    channel: PhantomData<CHANNEL>,
+}
+
+impl<SPI, TSTREAM, RSTREAM, CHANNEL> Spi<SPI, TSTREAM, RSTREAM, CHANNEL>
+where
+    SPI: Instance
+        + PeriAddress<MemSize = u8>
+        + DMASet<TSTREAM, CHANNEL, MemoryToPeripheral>
+        + DMASet<RSTREAM, CHANNEL, PeripheralToMemory>
+        + WithInterrupt,
+    TSTREAM: Stream + WithInterrupt,
+    RSTREAM: Stream + WithInterrupt,
+    CHANNEL: Channel,
+{
+    // Leaking futures is forbidden!
+    pub unsafe fn new<PINS>(
+        spi: SPI,
+        streams: (TSTREAM, RSTREAM),
+        pins: PINS,
+        tx_int: TSTREAM::Interrupt,
+        rx_int: RSTREAM::Interrupt,
+        spi_int: SPI::Interrupt,
+        mode: Mode,
+        freq: Hertz,
+        clocks: Clocks,
+    ) -> Self
+    where
+        PINS: Pins<SPI>,
+    {
+        let (tx_stream, rx_stream) = streams;
+
+        //        let spi1: crate::pac::SPI1 = unsafe { mem::transmute(()) };
+        //        let mut hspi = crate::hal::spi::Spi::spi1(
+        //            spi1,
+        //            (
+        //                crate::hal::spi::NoSck,
+        //                crate::hal::spi::NoMiso,
+        //                crate::hal::spi::NoMosi,
+        //            ),
+        //            mode,
+        //            freq,
+        //            clocks,
+        //        );
+
+        unsafe { SPI::enable_clock() };
+
+        let clock = SPI::clock_speed(clocks);
+
+        // disable SS output
+        // spi.cr2
+        //     .write(|w| w.ssoe().clear_bit().rxdmaen().set_bit().txdmaen().set_bit());
+        spi.cr2.write(|w| w.ssoe().clear_bit());
+
+        let br = match clock.0 / freq.0 {
+            0 => unreachable!(),
+            1..=2 => 0b000,
+            3..=5 => 0b001,
+            6..=11 => 0b010,
+            12..=23 => 0b011,
+            24..=47 => 0b100,
+            48..=95 => 0b101,
+            96..=191 => 0b110,
+            _ => 0b111,
+        };
+
+        // mstr: master configuration
+        // lsbfirst: MSB first
+        // ssm: enable software slave management (NSS pin free for other uses)
+        // ssi: set nss high = master mode
+        // dff: 8 bit frames
+        // bidimode: 2-line unidirectional
+        // spe: enable the SPI bus
+        spi.cr1.write(|w| {
+            w.cpha()
+                .bit(mode.phase == Phase::CaptureOnSecondTransition)
+                .cpol()
+                .bit(mode.polarity == Polarity::IdleHigh)
+                .mstr()
+                .set_bit()
+                .br()
+                .bits(br)
+                .lsbfirst()
+                .clear_bit()
+                .ssm()
+                .set_bit()
+                .ssi()
+                .set_bit()
+                .rxonly()
+                .clear_bit()
+                .dff()
+                .clear_bit()
+                .bidimode()
+                .clear_bit()
+                .spe()
+                .set_bit()
+        });
+
+        Self {
+            tx_stream: Some(tx_stream),
+            rx_stream: Some(rx_stream),
+            spi: Some(spi),
+            tx_int: tx_int,
+            rx_int: rx_int,
+            spi_int: spi_int,
+            channel: PhantomData,
+        }
+    }
+}
+
+impl<SPI, TSTREAM, RSTREAM, CHANNEL> FullDuplex<u8> for Spi<SPI, TSTREAM, RSTREAM, CHANNEL>
+where
+    SPI: Instance
+        + PeriAddress<MemSize = u8>
+        + DMASet<TSTREAM, CHANNEL, MemoryToPeripheral>
+        + DMASet<RSTREAM, CHANNEL, PeripheralToMemory>
+        + WithInterrupt
+        + 'static,
+    TSTREAM: Stream + WithInterrupt + 'static,
+    RSTREAM: Stream + WithInterrupt + 'static,
+    CHANNEL: Channel + 'static,
+{
+    type Error = Error;
+
+    type WriteFuture<'a> = impl Future<Output = Result<(), Error>> + 'a;
+    type ReadFuture<'a> = impl Future<Output = Result<(), Error>> + 'a;
+    type WriteReadFuture<'a> = impl Future<Output = Result<(), Error>> + 'a;
+
+    fn read<'a>(self: Pin<&'a mut Self>, buf: &'a mut [u8]) -> Self::ReadFuture<'a> {
+        let this = unsafe { self.get_unchecked_mut() };
+        #[allow(mutable_transmutes)]
+        let static_buf: &'static mut [u8] = unsafe { mem::transmute(buf) };
+
+        async move {
+            let rx_stream = this.rx_stream.take().unwrap();
+            let spi = this.spi.take().unwrap();
+
+            spi.cr2.modify(|_, w| w.errie().set_bit());
+
+            let mut rx_transfer = Transfer::init(
+                rx_stream,
+                spi,
+                static_buf,
+                None,
+                DmaConfig::default()
+                    .transfer_complete_interrupt(true)
+                    .memory_increment(true)
+                    .double_buffer(false),
+            );
+
+            let fut = InterruptFuture::new(&mut this.rx_int);
+            let fut_err = InterruptFuture::new(&mut this.spi_int);
+
+            rx_transfer.start(|_spi| {});
+            future::select(fut, fut_err).await;
+
+            let (rx_stream, spi, _buf, _) = rx_transfer.free();
+
+            spi.cr2.modify(|_, w| w.errie().clear_bit());
+            this.rx_stream.replace(rx_stream);
+            this.spi.replace(spi);
+
+            Ok(())
+        }
+    }
+
+    fn write<'a>(self: Pin<&'a mut Self>, buf: &'a [u8]) -> Self::WriteFuture<'a> {
+        let this = unsafe { self.get_unchecked_mut() };
+        #[allow(mutable_transmutes)]
+        let static_buf: &'static mut [u8] = unsafe { mem::transmute(buf) };
+
+        async move {
+            let tx_stream = this.tx_stream.take().unwrap();
+            let spi = this.spi.take().unwrap();
+
+            //            let mut tx_transfer = Transfer::init(
+            //                tx_stream,
+            //                spi,
+            //                static_buf,
+            //                None,
+            //                DmaConfig::default()
+            //                    .transfer_complete_interrupt(true)
+            //                    .memory_increment(true)
+            //                    .double_buffer(false),
+            //            );
+            //
+            //            let fut = InterruptFuture::new(&mut this.tx_int);
+            //
+            //            tx_transfer.start(|_spi| {});
+            //            fut.await;
+
+            // let (tx_stream, spi, _buf, _) = tx_transfer.free();
+
+            for i in 0..(static_buf.len() - 1) {
+                let byte = static_buf[i];
+                nb::block!(write_sr(&spi, byte));
+            }
+
+            this.tx_stream.replace(tx_stream);
+            this.spi.replace(spi);
+
+            Ok(())
+        }
+    }
+
+    fn read_write<'a>(
+        self: Pin<&'a mut Self>,
+        read_buf: &'a mut [u8],
+        write_buf: &'a [u8],
+    ) -> Self::WriteReadFuture<'a> {
+        let this = unsafe { self.get_unchecked_mut() };
+
+        #[allow(mutable_transmutes)]
+        let write_static_buf: &'static mut [u8] = unsafe { mem::transmute(write_buf) };
+        let read_static_buf: &'static mut [u8] = unsafe { mem::transmute(read_buf) };
+
+        async move {
+            let tx_stream = this.tx_stream.take().unwrap();
+            let rx_stream = this.rx_stream.take().unwrap();
+            let spi_tx = this.spi.take().unwrap();
+            let spi_rx: SPI = unsafe { mem::transmute_copy(&spi_tx) };
+
+            spi_rx
+                .cr2
+                .modify(|_, w| w.errie().set_bit().txeie().set_bit().rxneie().set_bit());
+
+            //            let mut tx_transfer = Transfer::init(
+            //                tx_stream,
+            //                spi_tx,
+            //                write_static_buf,
+            //                None,
+            //                DmaConfig::default()
+            //                    .transfer_complete_interrupt(true)
+            //                    .memory_increment(true)
+            //                    .double_buffer(false),
+            //            );
+            //
+            //            let mut rx_transfer = Transfer::init(
+            //                rx_stream,
+            //                spi_rx,
+            //                read_static_buf,
+            //                None,
+            //                DmaConfig::default()
+            //                    .transfer_complete_interrupt(true)
+            //                    .memory_increment(true)
+            //                    .double_buffer(false),
+            //            );
+            //
+            //            let tx_fut = InterruptFuture::new(&mut this.tx_int);
+            //            let rx_fut = InterruptFuture::new(&mut this.rx_int);
+            //            let rx_fut_err = InterruptFuture::new(&mut this.spi_int);
+            //
+            //            rx_transfer.start(|_spi| {});
+            //            tx_transfer.start(|_spi| {});
+            //
+            //            time::Timer::after(time::Duration::from_millis(500)).await;
+            //
+            //            // tx_fut.await;
+            //            // future::select(rx_fut, rx_fut_err).await;
+            //
+            //            let (rx_stream, spi_rx, _buf, _) = rx_transfer.free();
+            //            let (tx_stream, _, _buf, _) = tx_transfer.free();
+
+            for i in 0..(read_static_buf.len() - 1) {
+                let byte = write_static_buf[i];
+                loop {
+                    let fut = InterruptFuture::new(&mut this.spi_int);
+                    match write_sr(&spi_tx, byte) {
+                        Ok(()) => break,
+                        _ => {}
+                    }
+                    fut.await;
+                }
+
+                loop {
+                    let fut = InterruptFuture::new(&mut this.spi_int);
+                    match read_sr(&spi_tx) {
+                        Ok(byte) => {
+                            read_static_buf[i] = byte;
+                            break;
+                        }
+                        _ => {}
+                    }
+                    fut.await;
+                }
+            }
+
+            spi_rx.cr2.modify(|_, w| {
+                w.errie()
+                    .clear_bit()
+                    .txeie()
+                    .clear_bit()
+                    .rxneie()
+                    .clear_bit()
+            });
+            this.rx_stream.replace(rx_stream);
+            this.tx_stream.replace(tx_stream);
+            this.spi.replace(spi_rx);
+
+            Ok(())
+        }
+    }
+}
+
+mod private {
+    pub trait Sealed {}
+}
+
+pub trait WithInterrupt: private::Sealed {
+    type Interrupt: Interrupt;
+}
+
+pub trait Instance: Deref<Target = pac::spi1::RegisterBlock> + private::Sealed {
+    unsafe fn enable_clock();
+    fn clock_speed(clocks: Clocks) -> Hertz;
+}
+
+macro_rules! dma {
+     ($($PER:ident => ($dma:ident, $stream:ident),)+) => {
+         $(
+             impl private::Sealed for dma::$stream<pac::$dma> {}
+             impl WithInterrupt for dma::$stream<pac::$dma> {
+                 type Interrupt = interrupt::$PER;
+             }
+         )+
+     }
+ }
+
+macro_rules! spi {
+    ($($PER:ident => ($SPI:ident, $pclkX:ident,  $apbXenr:ident, $en:expr),)+) => {
+        $(
+            impl private::Sealed for pac::$SPI {}
+            impl Instance for pac::$SPI {
+                unsafe fn enable_clock() {
+                    const EN_BIT: u8 = $en;
+                    // NOTE(unsafe) this reference will only be used for atomic writes with no side effects.
+                    let rcc = &(*pac::RCC::ptr());
+                    // Enable clock.
+                    bb::set(&rcc.$apbXenr, EN_BIT);
+                    // Stall the pipeline to work around erratum 2.1.13 (DM00037591)
+                    cortex_m::asm::dsb();
+                }
+
+                fn clock_speed(clocks: Clocks) -> Hertz {
+                    clocks.$pclkX()
+                }
+            }
+            impl WithInterrupt for pac::$SPI {
+                type Interrupt = interrupt::$PER;
+            }
+        )+
+    }
+}
+
+dma! {
+    DMA2_STREAM0 => (DMA2, Stream0),
+    DMA2_STREAM1 => (DMA2, Stream1),
+    DMA2_STREAM2 => (DMA2, Stream2),
+    DMA2_STREAM3 => (DMA2, Stream3),
+    DMA2_STREAM4 => (DMA2, Stream4),
+    DMA2_STREAM5 => (DMA2, Stream5),
+    DMA2_STREAM6 => (DMA2, Stream6),
+    DMA2_STREAM7 => (DMA2, Stream7),
+    DMA1_STREAM0 => (DMA1, Stream0),
+    DMA1_STREAM1 => (DMA1, Stream1),
+    DMA1_STREAM2 => (DMA1, Stream2),
+    DMA1_STREAM3 => (DMA1, Stream3),
+    DMA1_STREAM4 => (DMA1, Stream4),
+    DMA1_STREAM5 => (DMA1, Stream5),
+    DMA1_STREAM6 => (DMA1, Stream6),
+}
+
+#[cfg(any(
+    feature = "stm32f401",
+    feature = "stm32f410",
+    feature = "stm32f411",
+    feature = "stm32f446",
+))]
+spi! {
+    SPI1 => (SPI1, pclk2, apb2enr, 12),
+    SPI2 => (SPI2, pclk1, apb2enr, 14),
+//    SPI6 => (SPI6, pclk2, apb2enr, 21),
+    SPI4 => (SPI3, pclk2, apb2enr, 13),
+//    SPI5 => (SPI3, pclk2, apb2enr, 20),
+}
+
+#[cfg(any(feature = "stm32f405", feature = "stm32f407"))]
+spi! {
+    SPI1 => (SPI1, pclk2, apb2enr, 12),
+    SPI3 => (SPI3, pclk1, apb2enr, 15),
+}
diff --git a/embassy-stm32/src/lib.rs b/embassy-stm32/src/lib.rs
index 370b5f0db..56efa461c 100644
--- a/embassy-stm32/src/lib.rs
+++ b/embassy-stm32/src/lib.rs
@@ -109,7 +109,7 @@ pub mod rtc;
     feature = "stm32f469",
     feature = "stm32f479",
 ))]
-pub use f4::serial;
+pub use f4::{serial, spi};
 
 #[cfg(any(
     feature = "stm32f401",