add separate tx waker

Author: meowcakes

embassy-stm32/src/usart/mod.rs

@@ -85,6 +85,7 @@ unsafe fn on_interrupt(r: Regs, s: &'static State) {
 
     compiler_fence(Ordering::SeqCst);
     s.rx_waker.wake();
+    s.tx_waker.wake();
 }
 
 #[derive(Clone, Copy, PartialEq, Eq, Debug)]
@@ -592,7 +593,7 @@ async fn flush(info: &Info, state: &State) -> Result<(), Error> {
 
         // future which completes when Transmission complete is detected
         let abort = poll_fn(move |cx| {
-            state.rx_waker.register(cx.waker());
+            state.tx_waker.register(cx.waker());
 
             let sr = sr(r).read();
             if sr.tc() {
@@ -2019,13 +2020,15 @@ enum Kind {
 
 struct State {
     rx_waker: AtomicWaker,
+    tx_waker: AtomicWaker,
     tx_rx_refcount: AtomicU8,
 }
 
 impl State {
     const fn new() -> Self {
         Self {
             rx_waker: AtomicWaker::new(),
+            tx_waker: AtomicWaker::new(),
             tx_rx_refcount: AtomicU8::new(0),
         }
     }