Add split() method to BufferedUarte in embassy-nrf

embassy-nrf/src/buffered_uarte.rs

@@ -13,6 +13,7 @@
 //!
 //! Please also see [crate::uarte] to understand when [BufferedUarte] should be used.
 
+use core::cell::RefCell;
 use core::cmp::min;
 use core::future::Future;
 use core::sync::atomic::{compiler_fence, Ordering};
@@ -71,7 +72,7 @@ struct StateInner<'d, U: UarteInstance, T: TimerInstance> {
 
 /// Interface to a UARTE instance
 pub struct BufferedUarte<'d, U: UarteInstance, T: TimerInstance> {
-    inner: PeripheralMutex<'d, StateInner<'d, U, T>>,
+    inner: RefCell<PeripheralMutex<'d, StateInner<'d, U, T>>>,
 }
 
 impl<'d, U: UarteInstance, T: TimerInstance> Unpin for BufferedUarte<'d, U, T> {}
@@ -169,7 +170,7 @@ impl<'d, U: UarteInstance, T: TimerInstance> BufferedUarte<'d, U, T> {
         ppi_ch2.enable();
 
         Self {
-            inner: PeripheralMutex::new(irq, &mut state.0, move || StateInner {
+            inner: RefCell::new(PeripheralMutex::new(irq, &mut state.0, move || StateInner {
                 _peri: peri,
                 timer,
                 _ppi_ch1: ppi_ch1,
@@ -182,13 +183,13 @@ impl<'d, U: UarteInstance, T: TimerInstance> BufferedUarte<'d, U, T> {
                 tx: RingBuffer::new(tx_buffer),
                 tx_state: TxState::Idle,
                 tx_waker: WakerRegistration::new(),
-            }),
+            })),
         }
     }
 
     /// Adjust the baud rate to the provided value.
     pub fn set_baudrate(&mut self, baudrate: Baudrate) {
-        self.inner.with(|state| {
+        self.inner.borrow_mut().with(|state| {
             let r = U::regs();
 
             let timeout = 0x8000_0000 / (baudrate as u32 / 40);
@@ -198,12 +199,35 @@ impl<'d, U: UarteInstance, T: TimerInstance> BufferedUarte<'d, U, T> {
             r.baudrate.write(|w| w.baudrate().variant(baudrate));
         });
     }
+
+    pub fn split<'u>(&'u mut self) -> (BufferedUarteRx<'u, 'd, U, T>, BufferedUarteTx<'u, 'd, U, T>) {
+        (
+            BufferedUarteRx { inner: &self.inner },
+            BufferedUarteTx { inner: &&self.inner },
+        )
+    }
+}
+
+pub struct BufferedUarteTx<'u, 'd, U: UarteInstance, T: TimerInstance> {
+    inner: &'u RefCell<PeripheralMutex<'d, StateInner<'d, U, T>>>,
+}
+
+pub struct BufferedUarteRx<'u, 'd, U: UarteInstance, T: TimerInstance> {
+    inner: &'u RefCell<PeripheralMutex<'d, StateInner<'d, U, T>>>,
 }
 
 impl<'d, U: UarteInstance, T: TimerInstance> embedded_io::Io for BufferedUarte<'d, U, T> {
     type Error = core::convert::Infallible;
 }
 
+impl<'u, 'd, U: UarteInstance, T: TimerInstance> embedded_io::Io for BufferedUarteRx<'u, 'd, U, T> {
+    type Error = core::convert::Infallible;
+}
+
+impl<'u, 'd, U: UarteInstance, T: TimerInstance> embedded_io::Io for BufferedUarteTx<'u, 'd, U, T> {
+    type Error = core::convert::Infallible;
+}
+
 impl<'d, U: UarteInstance, T: TimerInstance> embedded_io::asynch::Read for BufferedUarte<'d, U, T> {
     type ReadFuture<'a> = impl Future<Output = Result<usize, Self::Error>>
     where
@@ -212,7 +236,7 @@ impl<'d, U: UarteInstance, T: TimerInstance> embedded_io::asynch::Read for Buffe
     fn read<'a>(&'a mut self, buf: &'a mut [u8]) -> Self::ReadFuture<'a> {
         poll_fn(move |cx| {
             let mut do_pend = false;
-            let res = self.inner.with(|state| {
+            let res = self.inner.borrow_mut().with(|state| {
                 compiler_fence(Ordering::SeqCst);
                 trace!("poll_read");
 
@@ -232,7 +256,43 @@ impl<'d, U: UarteInstance, T: TimerInstance> embedded_io::asynch::Read for Buffe
                 Poll::Pending
             });
             if do_pend {
-                self.inner.pend();
+                self.inner.borrow().pend();
+            }
+
+            res
+        })
+    }
+}
+
+impl<'u, 'd: 'u, U: UarteInstance, T: TimerInstance> embedded_io::asynch::Read for BufferedUarteRx<'u, 'd, U, T> {
+    type ReadFuture<'a> = impl Future<Output = Result<usize, Self::Error>>
+    where
+        Self: 'a;
+
+    fn read<'a>(&'a mut self, buf: &'a mut [u8]) -> Self::ReadFuture<'a> {
+        poll_fn(move |cx| {
+            let mut do_pend = false;
+            let res = self.inner.borrow_mut().with(|state| {
+                compiler_fence(Ordering::SeqCst);
+                trace!("poll_read");
+
+                // We have data ready in buffer? Return it.
+                let data = state.rx.pop_buf();
+                if !data.is_empty() {
+                    trace!("  got {:?} {:?}", data.as_ptr() as u32, data.len());
+                    let len = data.len().min(buf.len());
+                    buf[..len].copy_from_slice(&data[..len]);
+                    state.rx.pop(len);
+                    do_pend = true;
+                    return Poll::Ready(Ok(len));
+                }
+
+                trace!("  empty");
+                state.rx_waker.register(cx.waker());
+                Poll::Pending
+            });
+            if do_pend {
+                self.inner.borrow().pend();
             }
 
             res
@@ -247,7 +307,7 @@ impl<'d, U: UarteInstance, T: TimerInstance> embedded_io::asynch::BufRead for Bu
 
     fn fill_buf<'a>(&'a mut self) -> Self::FillBufFuture<'a> {
         poll_fn(move |cx| {
-            self.inner.with(|state| {
+            self.inner.borrow_mut().with(|state| {
                 compiler_fence(Ordering::SeqCst);
                 trace!("fill_buf");
 
@@ -269,13 +329,53 @@ impl<'d, U: UarteInstance, T: TimerInstance> embedded_io::asynch::BufRead for Bu
     }
 
     fn consume(&mut self, amt: usize) {
-        let signal = self.inner.with(|state| {
+        let signal = self.inner.borrow_mut().with(|state| {
             let full = state.rx.is_full();
             state.rx.pop(amt);
             full
         });
         if signal {
-            self.inner.pend();
+            self.inner.borrow().pend();
+        }
+    }
+}
+
+impl<'u, 'd: 'u, U: UarteInstance, T: TimerInstance> embedded_io::asynch::BufRead for BufferedUarteRx<'u, 'd, U, T> {
+    type FillBufFuture<'a> = impl Future<Output = Result<&'a [u8], Self::Error>>
+    where
+        Self: 'a;
+
+    fn fill_buf<'a>(&'a mut self) -> Self::FillBufFuture<'a> {
+        poll_fn(move |cx| {
+            self.inner.borrow_mut().with(|state| {
+                compiler_fence(Ordering::SeqCst);
+                trace!("fill_buf");
+
+                // We have data ready in buffer? Return it.
+                let buf = state.rx.pop_buf();
+                if !buf.is_empty() {
+                    trace!("  got {:?} {:?}", buf.as_ptr() as u32, buf.len());
+                    let buf: &[u8] = buf;
+                    // Safety: buffer lives as long as uart
+                    let buf: &[u8] = unsafe { core::mem::transmute(buf) };
+                    return Poll::Ready(Ok(buf));
+                }
+
+                trace!("  empty");
+                state.rx_waker.register(cx.waker());
+                Poll::<Result<&[u8], Self::Error>>::Pending
+            })
+        })
+    }
+
+    fn consume(&mut self, amt: usize) {
+        let signal = self.inner.borrow_mut().with(|state| {
+            let full = state.rx.is_full();
+            state.rx.pop(amt);
+            full
+        });
+        if signal {
+            self.inner.borrow().pend();
         }
     }
 }
@@ -287,7 +387,7 @@ impl<'d, U: UarteInstance, T: TimerInstance> embedded_io::asynch::Write for Buff
 
     fn write<'a>(&'a mut self, buf: &'a [u8]) -> Self::WriteFuture<'a> {
         poll_fn(move |cx| {
-            let res = self.inner.with(|state| {
+            let res = self.inner.borrow_mut().with(|state| {
                 trace!("poll_write: {:?}", buf.len());
 
                 let tx_buf = state.tx.push_buf();
@@ -308,7 +408,7 @@ impl<'d, U: UarteInstance, T: TimerInstance> embedded_io::asynch::Write for Buff
                 Poll::Ready(Ok(n))
             });
 
-            self.inner.pend();
+            self.inner.borrow_mut().pend();
 
             res
         })
@@ -320,7 +420,62 @@ impl<'d, U: UarteInstance, T: TimerInstance> embedded_io::asynch::Write for Buff
 
     fn flush<'a>(&'a mut self) -> Self::FlushFuture<'a> {
         poll_fn(move |cx| {
-            self.inner.with(|state| {
+            self.inner.borrow_mut().with(|state| {
+                trace!("poll_flush");
+
+                if !state.tx.is_empty() {
+                    trace!("poll_flush: pending");
+                    state.tx_waker.register(cx.waker());
+                    return Poll::Pending;
+                }
+
+                Poll::Ready(Ok(()))
+            })
+        })
+    }
+}
+
+impl<'u, 'd: 'u, U: UarteInstance, T: TimerInstance> embedded_io::asynch::Write for BufferedUarteTx<'u, 'd, U, T> {
+    type WriteFuture<'a> = impl Future<Output = Result<usize, Self::Error>>
+    where
+        Self: 'a;
+
+    fn write<'a>(&'a mut self, buf: &'a [u8]) -> Self::WriteFuture<'a> {
+        poll_fn(move |cx| {
+            let res = self.inner.borrow_mut().with(|state| {
+                trace!("poll_write: {:?}", buf.len());
+
+                let tx_buf = state.tx.push_buf();
+                if tx_buf.is_empty() {
+                    trace!("poll_write: pending");
+                    state.tx_waker.register(cx.waker());
+                    return Poll::Pending;
+                }
+
+                let n = min(tx_buf.len(), buf.len());
+                tx_buf[..n].copy_from_slice(&buf[..n]);
+                state.tx.push(n);
+
+                trace!("poll_write: queued {:?}", n);
+
+                compiler_fence(Ordering::SeqCst);
+
+                Poll::Ready(Ok(n))
+            });
+
+            self.inner.borrow_mut().pend();
+
+            res
+        })
+    }
+
+    type FlushFuture<'a> = impl Future<Output = Result<(), Self::Error>>
+    where
+        Self: 'a;
+
+    fn flush<'a>(&'a mut self) -> Self::FlushFuture<'a> {
+        poll_fn(move |cx| {
+            self.inner.borrow_mut().with(|state| {
                 trace!("poll_flush");
 
                 if !state.tx.is_empty() {