Merge pull request #85 from embassy-rs/no-free

Simplify PeripheralMutex

embassy-extras/src/peripheral.rs

@@ -1,30 +1,20 @@
 use core::cell::UnsafeCell;
 use core::marker::{PhantomData, PhantomPinned};
-use core::mem::MaybeUninit;
 use core::pin::Pin;
 use core::sync::atomic::{compiler_fence, Ordering};
 
 use embassy::interrupt::{Interrupt, InterruptExt};
 
-use crate::fmt::assert;
-
 pub trait PeripheralState {
     type Interrupt: Interrupt;
     fn on_interrupt(&mut self);
 }
 
-#[derive(Clone, Copy, PartialEq, Eq, Debug)]
-enum Life {
-    Ready,
-    Created,
-    Freed,
-}
-
 pub struct PeripheralMutex<S: PeripheralState> {
-    life: Life,
+    state: UnsafeCell<S>,
 
-    state: MaybeUninit<UnsafeCell<S>>, // Init if life != Freed
+    irq_setup_done: bool,
-    irq: MaybeUninit<S::Interrupt>,    // Init if life != Freed
+    irq: S::Interrupt,
 
     _not_send: PhantomData<*mut ()>,
     _pinned: PhantomPinned,
@@ -33,87 +23,61 @@ pub struct PeripheralMutex<S: PeripheralState> {
 impl<S: PeripheralState> PeripheralMutex<S> {
     pub fn new(state: S, irq: S::Interrupt) -> Self {
         Self {
-            life: Life::Created,
+            irq,
-            state: MaybeUninit::new(UnsafeCell::new(state)),
+            irq_setup_done: false,
-            irq: MaybeUninit::new(irq),
+
+            state: UnsafeCell::new(state),
             _not_send: PhantomData,
             _pinned: PhantomPinned,
         }
     }
 
-    /// safety: self must be pinned.
+    pub fn register_interrupt(self: Pin<&mut Self>) {
-    unsafe fn setup(&mut self) {
+        let this = unsafe { self.get_unchecked_mut() };
-        assert!(self.life == Life::Created);
+        if this.irq_setup_done {
+            return;
+        }
 
-        let irq = &mut *self.irq.as_mut_ptr();
+        this.irq.disable();
-        irq.disable();
         compiler_fence(Ordering::SeqCst);
 
-        irq.set_handler(|p| {
+        this.irq.set_handler(|p| {
             // Safety: it's OK to get a &mut to the state, since
             // - We're in the IRQ, no one else can't preempt us
             // - We can't have preempted a with() call because the irq is disabled during it.
-            let state = &mut *(p as *mut S);
+            let state = unsafe { &mut *(p as *mut S) };
             state.on_interrupt();
         });
-        irq.set_handler_context(self.state.as_mut_ptr() as *mut ());
+        this.irq
+            .set_handler_context((&mut this.state) as *mut _ as *mut ());
 
         compiler_fence(Ordering::SeqCst);
-        irq.enable();
+        this.irq.enable();
 
-        self.life = Life::Ready;
+        this.irq_setup_done = true;
     }
 
     pub fn with<R>(self: Pin<&mut Self>, f: impl FnOnce(&mut S, &mut S::Interrupt) -> R) -> R {
         let this = unsafe { self.get_unchecked_mut() };
-        if this.life != Life::Ready {
-            unsafe { this.setup() }
-        }
 
-        let irq = unsafe { &mut *this.irq.as_mut_ptr() };
+        this.irq.disable();
-
-        irq.disable();
         compiler_fence(Ordering::SeqCst);
 
         // Safety: it's OK to get a &mut to the state, since the irq is disabled.
-        let state = unsafe { &mut *(*this.state.as_ptr()).get() };
+        let state = unsafe { &mut *this.state.get() };
 
-        let r = f(state, irq);
+        let r = f(state, &mut this.irq);
 
         compiler_fence(Ordering::SeqCst);
-        irq.enable();
+        this.irq.enable();
 
         r
     }
-
-    pub fn try_free(self: Pin<&mut Self>) -> Option<(S, S::Interrupt)> {
-        let this = unsafe { self.get_unchecked_mut() };
-
-        if this.life != Life::Freed {
-            return None;
-        }
-
-        unsafe { &mut *this.irq.as_mut_ptr() }.disable();
-        compiler_fence(Ordering::SeqCst);
-
-        this.life = Life::Freed;
-
-        let state = unsafe { this.state.as_ptr().read().into_inner() };
-        let irq = unsafe { this.irq.as_ptr().read() };
-        Some((state, irq))
-    }
-
-    pub fn free(self: Pin<&mut Self>) -> (S, S::Interrupt) {
-        unwrap!(self.try_free())
-    }
 }
 
 impl<S: PeripheralState> Drop for PeripheralMutex<S> {
     fn drop(&mut self) {
-        if self.life != Life::Freed {
+        self.irq.disable();
-            let irq = unsafe { &mut *self.irq.as_mut_ptr() };
+        self.irq.remove_handler();
-            irq.disable();
-            irq.remove_handler();
-        }
     }
 }

embassy-nrf/src/buffered_uarte.rs

@@ -201,36 +201,15 @@ impl<'a, U: Instance, T: TimerInstance, P1: ConfigurablePpi, P2: ConfigurablePpi
     fn inner(self: Pin<&mut Self>) -> Pin<&mut PeripheralMutex<State<'a, U, T, P1, P2>>> {
         unsafe { Pin::new_unchecked(&mut self.get_unchecked_mut().inner) }
     }
-
-    pub fn free(self: Pin<&mut Self>) -> (U, T, P1, P2, U::Interrupt) {
-        let (mut state, irq) = self.inner().free();
-        state.stop();
-        (
-            state.uarte,
-            state.timer,
-            state.ppi_channel_1,
-            state.ppi_channel_2,
-            irq,
-        )
-    }
-}
-
-impl<'a, U: Instance, T: TimerInstance, P1: ConfigurablePpi, P2: ConfigurablePpi> Drop
-    for BufferedUarte<'a, U, T, P1, P2>
-{
-    fn drop(&mut self) {
-        let inner = unsafe { Pin::new_unchecked(&mut self.inner) };
-        if let Some((mut state, _irq)) = inner.try_free() {
-            state.stop();
-        }
-    }
 }
 
 impl<'a, U: Instance, T: TimerInstance, P1: ConfigurablePpi, P2: ConfigurablePpi> AsyncBufRead
     for BufferedUarte<'a, U, T, P1, P2>
 {
     fn poll_fill_buf(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<&[u8]>> {
-        self.inner().with(|state, _irq| {
+        let mut inner = self.inner();
+        inner.as_mut().register_interrupt();
+        inner.with(|state, _irq| {
             // Conservative compiler fence to prevent optimizations that do not
             // take in to account actions by DMA. The fence has been placed here,
             // before any DMA action has started
@@ -253,7 +232,9 @@ impl<'a, U: Instance, T: TimerInstance, P1: ConfigurablePpi, P2: ConfigurablePpi
     }
 
     fn consume(self: Pin<&mut Self>, amt: usize) {
-        self.inner().with(|state, irq| {
+        let mut inner = self.inner();
+        inner.as_mut().register_interrupt();
+        inner.with(|state, irq| {
             trace!("consume {:?}", amt);
             state.rx.pop(amt);
             irq.pend();
@@ -265,7 +246,9 @@ impl<'a, U: Instance, T: TimerInstance, P1: ConfigurablePpi, P2: ConfigurablePpi
     for BufferedUarte<'a, U, T, P1, P2>
 {
     fn poll_write(self: Pin<&mut Self>, cx: &mut Context<'_>, buf: &[u8]) -> Poll<Result<usize>> {
-        self.inner().with(|state, irq| {
+        let mut inner = self.inner();
+        inner.as_mut().register_interrupt();
+        inner.with(|state, irq| {
             trace!("poll_write: {:?}", buf.len());
 
             let tx_buf = state.tx.push_buf();
@@ -293,10 +276,10 @@ impl<'a, U: Instance, T: TimerInstance, P1: ConfigurablePpi, P2: ConfigurablePpi
     }
 }
 
-impl<'a, U: Instance, T: TimerInstance, P1: ConfigurablePpi, P2: ConfigurablePpi>
+impl<'a, U: Instance, T: TimerInstance, P1: ConfigurablePpi, P2: ConfigurablePpi> Drop
-    State<'a, U, T, P1, P2>
+    for State<'a, U, T, P1, P2>
 {
-    fn stop(&mut self) {
+    fn drop(&mut self) {
         self.timer.tasks_stop.write(|w| unsafe { w.bits(1) });
         if let RxState::Receiving = self.rx_state {
             self.uarte.tasks_stoprx.write(|w| unsafe { w.bits(1) });

embassy-nrf/src/qspi.rs

@@ -238,11 +238,6 @@ impl Qspi {
         unsafe { Pin::new_unchecked(&mut self.get_unchecked_mut().inner) }
     }
 
-    pub fn free(self: Pin<&mut Self>) -> (QSPI, interrupt::QSPI) {
-        let (state, irq) = self.inner().free();
-        (state.inner, irq)
-    }
-
     fn wait_ready<'a>(mut self: Pin<&'a mut Self>) -> impl Future<Output = ()> + 'a {
         poll_fn(move |cx| {
             self.as_mut().inner().with(|s, _irq| {

embassy-nrf/src/spim.rs

@@ -120,11 +120,6 @@ impl<T: Instance> Spim<T> {
     fn inner(self: Pin<&mut Self>) -> Pin<&mut PeripheralMutex<State<T>>> {
         unsafe { Pin::new_unchecked(&mut self.get_unchecked_mut().inner) }
     }
-
-    pub fn free(self: Pin<&mut Self>) -> (T, T::Interrupt) {
-        let (state, irq) = self.inner().free();
-        (state.spim, irq)
-    }
 }
 
 impl<T: Instance> FullDuplex<u8> for Spim<T> {
@@ -153,6 +148,7 @@ impl<T: Instance> FullDuplex<u8> for Spim<T> {
             slice_in_ram_or(rx, Error::DMABufferNotInDataMemory)?;
             slice_in_ram_or(tx, Error::DMABufferNotInDataMemory)?;
 
+            self.as_mut().inner().register_interrupt();
             self.as_mut().inner().with(|s, _irq| {
                 // Conservative compiler fence to prevent optimizations that do not
                 // take in to account actions by DMA. The fence has been placed here,