From 1374ad2ab6a6f86a46c7c244568718a6bf8db041 Mon Sep 17 00:00:00 2001 From: huntc Date: Wed, 15 Dec 2021 17:51:26 +1100 Subject: [PATCH] Introduces split on the nRF Uarte A new `split` method is introduced such that the Uarte tx and rx can be used from separate tasks. An MPSC is used to illustrate how data may be passed between these tasks. --- embassy-nrf/src/uarte.rs | 230 +++++++++++++++++++++++++---- examples/nrf/src/bin/uart_split.rs | 68 +++++++++ 2 files changed, 273 insertions(+), 25 deletions(-) create mode 100644 examples/nrf/src/bin/uart_split.rs diff --git a/embassy-nrf/src/uarte.rs b/embassy-nrf/src/uarte.rs index ff781cab..b0a28a5d 100644 --- a/embassy-nrf/src/uarte.rs +++ b/embassy-nrf/src/uarte.rs @@ -54,6 +54,20 @@ impl Default for Config { /// Interface to the UARTE peripheral pub struct Uarte<'d, T: Instance> { phantom: PhantomData<&'d mut T>, + tx: UarteTx<'d, T>, + rx: UarteRx<'d, T>, +} + +/// Transmitter interface to the UARTE peripheral obtained +/// via [Uarte]::split. +pub struct UarteTx<'d, T: Instance> { + phantom: PhantomData<&'d mut T>, +} + +/// Receiver interface to the UARTE peripheral obtained +/// via [Uarte]::split. +pub struct UarteRx<'d, T: Instance> { + phantom: PhantomData<&'d mut T>, } impl<'d, T: Instance> Uarte<'d, T> { @@ -121,9 +135,18 @@ impl<'d, T: Instance> Uarte<'d, T> { Self { phantom: PhantomData, + tx: UarteTx::new(), + rx: UarteRx::new(), } } + /// Split the Uarte into a transmitter and receiver, which is + /// particuarly useful when having two tasks correlating to + /// transmitting and receiving. + pub fn split(self) -> (UarteTx<'d, T>, UarteRx<'d, T>) { + (self.tx, self.rx) + } + fn on_interrupt(_: *mut ()) { let r = T::regs(); let s = T::state(); @@ -139,34 +162,33 @@ impl<'d, T: Instance> Uarte<'d, T> { } } -impl<'a, T: Instance> Drop for Uarte<'a, T> { - fn drop(&mut self) { - info!("uarte drop"); +impl<'d, T: Instance> Read for Uarte<'d, T> { + #[rustfmt::skip] + type ReadFuture<'a> where Self: 'a = impl Future> + 'a; - let r = T::regs(); - - let did_stoprx = r.events_rxstarted.read().bits() != 0; - let did_stoptx = r.events_txstarted.read().bits() != 0; - info!("did_stoprx {} did_stoptx {}", did_stoprx, did_stoptx); - - // Wait for rxto or txstopped, if needed. - while (did_stoprx && r.events_rxto.read().bits() == 0) - || (did_stoptx && r.events_txstopped.read().bits() == 0) - {} - - // Finally we can disable! - r.enable.write(|w| w.enable().disabled()); - - gpio::deconfigure_pin(r.psel.rxd.read().bits()); - gpio::deconfigure_pin(r.psel.txd.read().bits()); - gpio::deconfigure_pin(r.psel.rts.read().bits()); - gpio::deconfigure_pin(r.psel.cts.read().bits()); - - info!("uarte drop: done"); + fn read<'a>(&'a mut self, rx_buffer: &'a mut [u8]) -> Self::ReadFuture<'a> { + self.rx.read(rx_buffer) } } -impl<'d, T: Instance> Read for Uarte<'d, T> { +impl<'d, T: Instance> Write for Uarte<'d, T> { + #[rustfmt::skip] + type WriteFuture<'a> where Self: 'a = impl Future> + 'a; + + fn write<'a>(&'a mut self, tx_buffer: &'a [u8]) -> Self::WriteFuture<'a> { + self.tx.write(tx_buffer) + } +} + +impl<'d, T: Instance> UarteTx<'d, T> { + pub fn new() -> Self { + Self { + phantom: PhantomData, + } + } +} + +impl<'d, T: Instance> Read for UarteTx<'d, T> { #[rustfmt::skip] type ReadFuture<'a> where Self: 'a = impl Future> + 'a; @@ -220,7 +242,7 @@ impl<'d, T: Instance> Read for Uarte<'d, T> { } } -impl<'d, T: Instance> Write for Uarte<'d, T> { +impl<'d, T: Instance> Write for UarteTx<'d, T> { #[rustfmt::skip] type WriteFuture<'a> where Self: 'a = impl Future> + 'a; @@ -275,6 +297,164 @@ impl<'d, T: Instance> Write for Uarte<'d, T> { } } +impl<'a, T: Instance> Drop for UarteTx<'a, T> { + fn drop(&mut self) { + info!("uarte tx drop"); + + let r = T::regs(); + + let did_stoptx = r.events_txstarted.read().bits() != 0; + info!("did_stoptx {}", did_stoptx); + + // Wait for txstopped, if needed. + while did_stoptx && r.events_txstopped.read().bits() == 0 {} + + info!("uarte txdrop: done"); + } +} + +impl<'d, T: Instance> UarteRx<'d, T> { + pub fn new() -> Self { + Self { + phantom: PhantomData, + } + } +} + +impl<'d, T: Instance> Read for UarteRx<'d, T> { + #[rustfmt::skip] + type ReadFuture<'a> where Self: 'a = impl Future> + 'a; + + fn read<'a>(&'a mut self, rx_buffer: &'a mut [u8]) -> Self::ReadFuture<'a> { + async move { + let ptr = rx_buffer.as_ptr(); + let len = rx_buffer.len(); + assert!(len <= EASY_DMA_SIZE); + + let r = T::regs(); + let s = T::state(); + + let drop = OnDrop::new(move || { + info!("read drop: stopping"); + + r.intenclr.write(|w| w.endrx().clear()); + r.events_rxto.reset(); + r.tasks_stoprx.write(|w| unsafe { w.bits(1) }); + + while r.events_endrx.read().bits() == 0 {} + + info!("read drop: stopped"); + }); + + r.rxd.ptr.write(|w| unsafe { w.ptr().bits(ptr as u32) }); + r.rxd.maxcnt.write(|w| unsafe { w.maxcnt().bits(len as _) }); + + r.events_endrx.reset(); + r.intenset.write(|w| w.endrx().set()); + + compiler_fence(Ordering::SeqCst); + + trace!("startrx"); + r.tasks_startrx.write(|w| unsafe { w.bits(1) }); + + poll_fn(|cx| { + s.endrx_waker.register(cx.waker()); + if r.events_endrx.read().bits() != 0 { + return Poll::Ready(()); + } + Poll::Pending + }) + .await; + + compiler_fence(Ordering::SeqCst); + r.events_rxstarted.reset(); + drop.defuse(); + + Ok(()) + } + } +} + +impl<'d, T: Instance> Write for UarteRx<'d, T> { + #[rustfmt::skip] + type WriteFuture<'a> where Self: 'a = impl Future> + 'a; + + fn write<'a>(&'a mut self, tx_buffer: &'a [u8]) -> Self::WriteFuture<'a> { + async move { + let ptr = tx_buffer.as_ptr(); + let len = tx_buffer.len(); + assert!(len <= EASY_DMA_SIZE); + // TODO: panic if buffer is not in SRAM + + let r = T::regs(); + let s = T::state(); + + let drop = OnDrop::new(move || { + info!("write drop: stopping"); + + r.intenclr.write(|w| w.endtx().clear()); + r.events_txstopped.reset(); + r.tasks_stoptx.write(|w| unsafe { w.bits(1) }); + + // TX is stopped almost instantly, spinning is fine. + while r.events_endtx.read().bits() == 0 {} + info!("write drop: stopped"); + }); + + r.txd.ptr.write(|w| unsafe { w.ptr().bits(ptr as u32) }); + r.txd.maxcnt.write(|w| unsafe { w.maxcnt().bits(len as _) }); + + r.events_endtx.reset(); + r.intenset.write(|w| w.endtx().set()); + + compiler_fence(Ordering::SeqCst); + + trace!("starttx"); + r.tasks_starttx.write(|w| unsafe { w.bits(1) }); + + poll_fn(|cx| { + s.endtx_waker.register(cx.waker()); + if r.events_endtx.read().bits() != 0 { + return Poll::Ready(()); + } + Poll::Pending + }) + .await; + + compiler_fence(Ordering::SeqCst); + r.events_txstarted.reset(); + drop.defuse(); + + Ok(()) + } + } +} + +impl<'a, T: Instance> Drop for UarteRx<'a, T> { + fn drop(&mut self) { + info!("uarte rx drop"); + + let r = T::regs(); + + let did_stoprx = r.events_rxstarted.read().bits() != 0; + info!("did_stoprx {}", did_stoprx); + + // Wait for rxto, if needed. + while did_stoprx && r.events_rxto.read().bits() == 0 {} + + // Finally we can disable, and we do so for the peripheral + // i.e. not just rx concerns. + r.enable.write(|w| w.enable().disabled()); + + gpio::deconfigure_pin(r.psel.rxd.read().bits()); + gpio::deconfigure_pin(r.psel.txd.read().bits()); + gpio::deconfigure_pin(r.psel.rts.read().bits()); + gpio::deconfigure_pin(r.psel.cts.read().bits()); + + info!("uarte drop: done"); + } +} + #[cfg(not(any(feature = "_nrf9160", feature = "nrf5340")))] pub(in crate) fn apply_workaround_for_enable_anomaly(_r: &crate::pac::uarte0::RegisterBlock) { // Do nothing diff --git a/examples/nrf/src/bin/uart_split.rs b/examples/nrf/src/bin/uart_split.rs new file mode 100644 index 00000000..4b5dbb21 --- /dev/null +++ b/examples/nrf/src/bin/uart_split.rs @@ -0,0 +1,68 @@ +#![no_std] +#![no_main] +#![feature(type_alias_impl_trait)] + +#[path = "../example_common.rs"] +mod example_common; +use embassy::blocking_mutex::kind::Noop; +use embassy::channel::mpsc::{self, Channel, Sender}; +use embassy::util::Forever; +use embassy_nrf::peripherals::UARTE0; +use embassy_nrf::uarte::UarteRx; +use example_common::*; + +use embassy::executor::Spawner; +use embassy::traits::uart::{Read, Write}; +use embassy_nrf::gpio::NoPin; +use embassy_nrf::{interrupt, uarte, Peripherals}; + +static CHANNEL: Forever> = Forever::new(); + +#[embassy::main] +async fn main(spawner: Spawner, p: Peripherals) { + let mut config = uarte::Config::default(); + config.parity = uarte::Parity::EXCLUDED; + config.baudrate = uarte::Baudrate::BAUD115200; + + let irq = interrupt::take!(UARTE0_UART0); + let uart = uarte::Uarte::new(p.UARTE0, irq, p.P0_08, p.P0_06, NoPin, NoPin, config); + let (mut tx, rx) = uart.split(); + + let c = CHANNEL.put(Channel::new()); + let (s, mut r) = mpsc::split(c); + + info!("uarte initialized!"); + + // Spawn a task responsible purely for reading + + unwrap!(spawner.spawn(reader(rx, s))); + + // Message must be in SRAM + { + let mut buf = [0; 23]; + buf.copy_from_slice(b"Type 8 chars to echo!\r\n"); + + unwrap!(tx.write(&buf).await); + info!("wrote hello in uart!"); + } + + // Continue reading in this main task and write + // back out the buffer we receive from the read + // task. + loop { + if let Some(buf) = r.recv().await { + info!("writing..."); + unwrap!(tx.write(&buf).await); + } + } +} + +#[embassy::task] +async fn reader(mut rx: UarteRx<'static, UARTE0>, s: Sender<'static, Noop, [u8; 8], 1>) { + let mut buf = [0; 8]; + loop { + info!("reading..."); + unwrap!(rx.read(&mut buf).await); + unwrap!(s.send(buf).await); + } +}