4 files changed, 264 insertions, 197 deletions

diff --git a/embassy-nrf/src/uarte.rs b/embassy-nrf/src/uarte.rs
index 38480ecca..07cec5d6b 100644
--- a/embassy-nrf/src/uarte.rs
+++ b/embassy-nrf/src/uarte.rs
@@ -13,12 +13,10 @@
 //! memory may be used given that buffers are passed in directly to its read and write
 //! methods.
 
-use core::future::Future;
 use core::marker::PhantomData;
 use core::sync::atomic::{compiler_fence, Ordering};
 use core::task::Poll;
 use embassy::interrupt::InterruptExt;
-use embassy::traits::uart::{Error as TraitError, Read, ReadUntilIdle, Write};
 use embassy::util::Unborrow;
 use embassy_hal_common::drop::OnDrop;
 use embassy_hal_common::unborrow;
@@ -32,6 +30,7 @@ use crate::pac;
 use crate::ppi::{AnyConfigurableChannel, ConfigurableChannel, Event, Ppi, Task};
 use crate::timer::Instance as TimerInstance;
 use crate::timer::{Frequency, Timer};
+use crate::util::slice_in_ram_or;
 
 // Re-export SVD variants to allow user to directly set values.
 pub use pac::uarte0::{baudrate::BAUDRATE_A as Baudrate, config::PARITY_A as Parity};
@@ -51,6 +50,16 @@ impl Default for Config {
     }
 }
 
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
+#[non_exhaustive]
+pub enum Error {
+    BufferTooLong,
+    BufferZeroLength,
+    DMABufferNotInDataMemory,
+    // TODO: add other error variants.
+}
+
 /// Interface to the UARTE peripheral
 pub struct Uarte<'d, T: Instance> {
     phantom: PhantomData<&'d mut T>,
@@ -139,8 +148,12 @@ impl<'d, T: Instance> Uarte<'d, T> {
 
         Self {
             phantom: PhantomData,
-            tx: UarteTx::new(),
-            rx: UarteRx::new(),
+            tx: UarteTx {
+                phantom: PhantomData,
+            },
+            rx: UarteRx {
+                phantom: PhantomData,
+            },
         }
     }
 
@@ -170,92 +183,110 @@ impl<'d, T: Instance> Uarte<'d, T> {
             r.intenclr.write(|w| w.endtx().clear());
         }
     }
-}
 
-impl<'d, T: Instance> Read for Uarte<'d, T> {
-    type ReadFuture<'a>
-    where
-        Self: 'a,
-    = impl Future<Output = Result<(), TraitError>> + 'a;
+    pub async fn read(&mut self, buffer: &mut [u8]) -> Result<(), Error> {
+        self.rx.read(buffer).await
+    }
 
-    fn read<'a>(&'a mut self, rx_buffer: &'a mut [u8]) -> Self::ReadFuture<'a> {
-        self.rx.read(rx_buffer)
+    pub async fn write(&mut self, buffer: &[u8]) -> Result<(), Error> {
+        self.tx.write(buffer).await
     }
-}
 
-impl<'d, T: Instance> Write for Uarte<'d, T> {
-    type WriteFuture<'a>
-    where
-        Self: 'a,
-    = impl Future<Output = Result<(), TraitError>> + 'a;
+    pub fn blocking_read(&mut self, buffer: &mut [u8]) -> Result<(), Error> {
+        self.rx.blocking_read(buffer)
+    }
 
-    fn write<'a>(&'a mut self, tx_buffer: &'a [u8]) -> Self::WriteFuture<'a> {
-        self.tx.write(tx_buffer)
+    pub fn blocking_write(&mut self, buffer: &[u8]) -> Result<(), Error> {
+        self.tx.blocking_write(buffer)
     }
 }
 
 impl<'d, T: Instance> UarteTx<'d, T> {
-    pub fn new() -> Self {
-        Self {
-            phantom: PhantomData,
+    pub async fn write(&mut self, buffer: &[u8]) -> Result<(), Error> {
+        slice_in_ram_or(buffer, Error::DMABufferNotInDataMemory)?;
+        if buffer.len() == 0 {
+            return Err(Error::BufferZeroLength);
+        }
+        if buffer.len() > EASY_DMA_SIZE {
+            return Err(Error::BufferTooLong);
         }
-    }
-}
 
-impl<'d, T: Instance> Write for UarteTx<'d, T> {
-    type WriteFuture<'a>
-    where
-        Self: 'a,
-    = impl Future<Output = Result<(), TraitError>> + 'a;
+        let ptr = buffer.as_ptr();
+        let len = buffer.len();
 
-    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 r = T::regs();
-            let s = T::state();
+        let drop = OnDrop::new(move || {
+            trace!("write drop: stopping");
 
-            let drop = OnDrop::new(move || {
-                trace!("write drop: stopping");
+            r.intenclr.write(|w| w.endtx().clear());
+            r.events_txstopped.reset();
+            r.tasks_stoptx.write(|w| unsafe { w.bits(1) });
 
-                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 {}
+            trace!("write drop: stopped");
+        });
 
-                // TX is stopped almost instantly, spinning is fine.
-                while r.events_endtx.read().bits() == 0 {}
-                trace!("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.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());
 
-            r.events_endtx.reset();
-            r.intenset.write(|w| w.endtx().set());
+        compiler_fence(Ordering::SeqCst);
 
-            compiler_fence(Ordering::SeqCst);
+        trace!("starttx");
+        r.tasks_starttx.write(|w| unsafe { w.bits(1) });
 
-            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;
 
-            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();
 
-            compiler_fence(Ordering::SeqCst);
-            r.events_txstarted.reset();
-            drop.defuse();
+        Ok(())
+    }
 
-            Ok(())
+    pub fn blocking_write(&mut self, buffer: &[u8]) -> Result<(), Error> {
+        slice_in_ram_or(buffer, Error::DMABufferNotInDataMemory)?;
+        if buffer.len() == 0 {
+            return Err(Error::BufferZeroLength);
+        }
+        if buffer.len() > EASY_DMA_SIZE {
+            return Err(Error::BufferTooLong);
         }
+
+        let ptr = buffer.as_ptr();
+        let len = buffer.len();
+
+        let r = T::regs();
+
+        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.intenclr.write(|w| w.endtx().clear());
+
+        compiler_fence(Ordering::SeqCst);
+
+        trace!("starttx");
+        r.tasks_starttx.write(|w| unsafe { w.bits(1) });
+
+        while r.events_endtx.read().bits() == 0 {}
+
+        compiler_fence(Ordering::SeqCst);
+        r.events_txstarted.reset();
+
+        Ok(())
     }
 }
 
@@ -278,66 +309,89 @@ impl<'a, T: Instance> Drop for UarteTx<'a, T> {
 }
 
 impl<'d, T: Instance> UarteRx<'d, T> {
-    pub fn new() -> Self {
-        Self {
-            phantom: PhantomData,
+    pub async fn read(&mut self, buffer: &mut [u8]) -> Result<(), Error> {
+        if buffer.len() == 0 {
+            return Err(Error::BufferZeroLength);
+        }
+        if buffer.len() > EASY_DMA_SIZE {
+            return Err(Error::BufferTooLong);
         }
-    }
-}
 
-impl<'d, T: Instance> Read for UarteRx<'d, T> {
-    type ReadFuture<'a>
-    where
-        Self: 'a,
-    = impl Future<Output = Result<(), TraitError>> + 'a;
+        let ptr = buffer.as_ptr();
+        let len = buffer.len();
 
-    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 r = T::regs();
-            let s = T::state();
+        let drop = OnDrop::new(move || {
+            trace!("read drop: stopping");
 
-            let drop = OnDrop::new(move || {
-                trace!("read drop: stopping");
+            r.intenclr.write(|w| w.endrx().clear());
+            r.events_rxto.reset();
+            r.tasks_stoprx.write(|w| unsafe { w.bits(1) });
 
-                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 {}
 
-                while r.events_endrx.read().bits() == 0 {}
+            trace!("read drop: stopped");
+        });
 
-                trace!("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.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());
 
-            r.events_endrx.reset();
-            r.intenset.write(|w| w.endrx().set());
+        compiler_fence(Ordering::SeqCst);
 
-            compiler_fence(Ordering::SeqCst);
+        trace!("startrx");
+        r.tasks_startrx.write(|w| unsafe { w.bits(1) });
 
-            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;
 
-            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();
 
-            compiler_fence(Ordering::SeqCst);
-            r.events_rxstarted.reset();
-            drop.defuse();
+        Ok(())
+    }
 
-            Ok(())
+    pub fn blocking_read(&mut self, buffer: &mut [u8]) -> Result<(), Error> {
+        if buffer.len() == 0 {
+            return Err(Error::BufferZeroLength);
+        }
+        if buffer.len() > EASY_DMA_SIZE {
+            return Err(Error::BufferTooLong);
         }
+
+        let ptr = buffer.as_ptr();
+        let len = buffer.len();
+
+        let r = T::regs();
+
+        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.intenclr.write(|w| w.endrx().clear());
+
+        compiler_fence(Ordering::SeqCst);
+
+        trace!("startrx");
+        r.tasks_startrx.write(|w| unsafe { w.bits(1) });
+
+        while r.events_endrx.read().bits() == 0 {}
+
+        compiler_fence(Ordering::SeqCst);
+        r.events_rxstarted.reset();
+
+        Ok(())
     }
 }
 
@@ -439,14 +493,7 @@ pub struct UarteWithIdle<'d, U: Instance, T: TimerInstance> {
 impl<'d, U: Instance, T: TimerInstance> UarteWithIdle<'d, U, T> {
     /// Creates the interface to a UARTE instance.
     /// Sets the baud rate, parity and assigns the pins to the UARTE peripheral.
-    ///
-    /// # Safety
-    ///
-    /// The returned API is safe unless you use `mem::forget` (or similar safe mechanisms)
-    /// on stack allocated buffers which which have been passed to [`send()`](Uarte::send)
-    /// or [`receive`](Uarte::receive).
-    #[allow(unused_unsafe)]
-    pub unsafe fn new(
+    pub fn new(
         uarte: impl Unborrow<Target = U> + 'd,
         timer: impl Unborrow<Target = T> + 'd,
         ppi_ch1: impl Unborrow<Target = impl ConfigurableChannel + 'd> + 'd,
@@ -501,93 +548,119 @@ impl<'d, U: Instance, T: TimerInstance> UarteWithIdle<'d, U, T> {
             _ppi_ch2: ppi_ch2,
         }
     }
-}
 
-impl<'d, U: Instance, T: TimerInstance> ReadUntilIdle for UarteWithIdle<'d, U, T> {
-    type ReadUntilIdleFuture<'a>
-    where
-        Self: 'a,
-    = impl Future<Output = Result<usize, TraitError>> + 'a;
-    fn read_until_idle<'a>(&'a mut self, rx_buffer: &'a mut [u8]) -> Self::ReadUntilIdleFuture<'a> {
-        async move {
-            let ptr = rx_buffer.as_ptr();
-            let len = rx_buffer.len();
-            assert!(len <= EASY_DMA_SIZE);
+    pub async fn read(&mut self, buffer: &mut [u8]) -> Result<(), Error> {
+        self.ppi_ch1.disable();
+        self.uarte.read(buffer).await
+    }
 
-            let r = U::regs();
-            let s = U::state();
+    pub async fn write(&mut self, buffer: &[u8]) -> Result<(), Error> {
+        self.uarte.write(buffer).await
+    }
 
-            let drop = OnDrop::new(|| {
-                trace!("read drop: stopping");
+    pub fn blocking_read(&mut self, buffer: &mut [u8]) -> Result<(), Error> {
+        self.ppi_ch1.disable();
+        self.uarte.blocking_read(buffer)
+    }
 
-                self.timer.stop();
+    pub fn blocking_write(&mut self, buffer: &[u8]) -> Result<(), Error> {
+        self.uarte.blocking_write(buffer)
+    }
 
-                r.intenclr.write(|w| w.endrx().clear());
-                r.events_rxto.reset();
-                r.tasks_stoprx.write(|w| unsafe { w.bits(1) });
+    pub async fn read_until_idle(&mut self, buffer: &mut [u8]) -> Result<usize, Error> {
+        if buffer.len() == 0 {
+            return Err(Error::BufferZeroLength);
+        }
+        if buffer.len() > EASY_DMA_SIZE {
+            return Err(Error::BufferTooLong);
+        }
 
-                while r.events_endrx.read().bits() == 0 {}
+        let ptr = buffer.as_ptr();
+        let len = buffer.len();
 
-                trace!("read drop: stopped");
-            });
+        let r = U::regs();
+        let s = U::state();
 
-            r.rxd.ptr.write(|w| unsafe { w.ptr().bits(ptr as u32) });
-            r.rxd.maxcnt.write(|w| unsafe { w.maxcnt().bits(len as _) });
+        self.ppi_ch1.enable();
 
-            r.events_endrx.reset();
-            r.intenset.write(|w| w.endrx().set());
+        let drop = OnDrop::new(|| {
+            trace!("read drop: stopping");
 
-            compiler_fence(Ordering::SeqCst);
+            self.timer.stop();
 
-            trace!("startrx");
-            r.tasks_startrx.write(|w| unsafe { w.bits(1) });
+            r.intenclr.write(|w| w.endrx().clear());
+            r.events_rxto.reset();
+            r.tasks_stoprx.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;
+            while r.events_endrx.read().bits() == 0 {}
 
-            compiler_fence(Ordering::SeqCst);
-            let n = r.rxd.amount.read().amount().bits() as usize;
+            trace!("read drop: stopped");
+        });
 
-            // Stop timer
-            self.timer.stop();
-            r.events_rxstarted.reset();
+        r.rxd.ptr.write(|w| unsafe { w.ptr().bits(ptr as u32) });
+        r.rxd.maxcnt.write(|w| unsafe { w.maxcnt().bits(len as _) });
 
-            drop.defuse();
+        r.events_endrx.reset();
+        r.intenset.write(|w| w.endrx().set());
 
-            Ok(n)
-        }
+        compiler_fence(Ordering::SeqCst);
+
+        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);
+        let n = r.rxd.amount.read().amount().bits() as usize;
+
+        self.timer.stop();
+        r.events_rxstarted.reset();
+
+        drop.defuse();
+
+        Ok(n)
     }
-}
 
-impl<'d, U: Instance, T: TimerInstance> Read for UarteWithIdle<'d, U, T> {
-    type ReadFuture<'a>
-    where
-        Self: 'a,
-    = impl Future<Output = Result<(), TraitError>> + 'a;
-    fn read<'a>(&'a mut self, rx_buffer: &'a mut [u8]) -> Self::ReadFuture<'a> {
-        async move {
-            self.ppi_ch1.disable();
-            let result = self.uarte.read(rx_buffer).await;
-            self.ppi_ch1.enable();
-            result
+    pub fn blocking_read_until_idle(&mut self, buffer: &mut [u8]) -> Result<usize, Error> {
+        if buffer.len() == 0 {
+            return Err(Error::BufferZeroLength);
+        }
+        if buffer.len() > EASY_DMA_SIZE {
+            return Err(Error::BufferTooLong);
         }
-    }
-}
 
-impl<'d, U: Instance, T: TimerInstance> Write for UarteWithIdle<'d, U, T> {
-    type WriteFuture<'a>
-    where
-        Self: 'a,
-    = impl Future<Output = Result<(), TraitError>> + 'a;
+        let ptr = buffer.as_ptr();
+        let len = buffer.len();
+
+        let r = U::regs();
+
+        self.ppi_ch1.enable();
+
+        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.intenclr.write(|w| w.endrx().clear());
+
+        compiler_fence(Ordering::SeqCst);
+
+        r.tasks_startrx.write(|w| unsafe { w.bits(1) });
+
+        while r.events_endrx.read().bits() == 0 {}
+
+        compiler_fence(Ordering::SeqCst);
+        let n = r.rxd.amount.read().amount().bits() as usize;
+
+        self.timer.stop();
+        r.events_rxstarted.reset();
 
-    fn write<'a>(&'a mut self, tx_buffer: &'a [u8]) -> Self::WriteFuture<'a> {
-        self.uarte.write(tx_buffer)
+        Ok(n)
     }
 }
 
diff --git a/examples/nrf/src/bin/uart.rs b/examples/nrf/src/bin/uart.rs
index 208961c8b..68ee3978a 100644
--- a/examples/nrf/src/bin/uart.rs
+++ b/examples/nrf/src/bin/uart.rs
@@ -7,7 +7,6 @@ mod example_common;
 use example_common::*;
 
 use embassy::executor::Spawner;
-use embassy::traits::uart::{Read, Write};
 use embassy_nrf::gpio::NoPin;
 use embassy_nrf::{interrupt, uarte, Peripherals};
 
diff --git a/examples/nrf/src/bin/uart_idle.rs b/examples/nrf/src/bin/uart_idle.rs
index ec9a36026..76449c0e3 100644
--- a/examples/nrf/src/bin/uart_idle.rs
+++ b/examples/nrf/src/bin/uart_idle.rs
@@ -4,11 +4,9 @@
 
 #[path = "../example_common.rs"]
 mod example_common;
-use embassy_traits::uart::ReadUntilIdle;
 use example_common::*;
 
 use embassy::executor::Spawner;
-use embassy::traits::uart::Write;
 use embassy_nrf::gpio::NoPin;
 use embassy_nrf::{interrupt, uarte, Peripherals};
 
@@ -19,11 +17,9 @@ async fn main(_spawner: Spawner, p: Peripherals) {
     config.baudrate = uarte::Baudrate::BAUD115200;
 
     let irq = interrupt::take!(UARTE0_UART0);
-    let mut uart = unsafe {
-        uarte::UarteWithIdle::new(
-            p.UARTE0, p.TIMER0, p.PPI_CH0, p.PPI_CH1, irq, p.P0_08, p.P0_06, NoPin, NoPin, config,
-        )
-    };
+    let mut uart = uarte::UarteWithIdle::new(
+        p.UARTE0, p.TIMER0, p.PPI_CH0, p.PPI_CH1, irq, p.P0_08, p.P0_06, NoPin, NoPin, config,
+    );
 
     info!("uarte initialized!");
 
diff --git a/examples/nrf/src/bin/uart_split.rs b/examples/nrf/src/bin/uart_split.rs
index 4b5dbb21f..a9c02e796 100644
--- a/examples/nrf/src/bin/uart_split.rs
+++ b/examples/nrf/src/bin/uart_split.rs
@@ -4,16 +4,15 @@
 
 #[path = "../example_common.rs"]
 mod example_common;
+use example_common::*;
+
 use embassy::blocking_mutex::kind::Noop;
 use embassy::channel::mpsc::{self, Channel, Sender};
+use embassy::executor::Spawner;
 use embassy::util::Forever;
+use embassy_nrf::gpio::NoPin;
 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<Channel<Noop, [u8; 8], 1>> = Forever::new();