From b5e0116f76a4b6023a637c5edb3e6a7995c954ca Mon Sep 17 00:00:00 2001
From: xoviat <xoviat@gmail.com>
Date: Mon, 28 Dec 2020 13:31:18 -0600
Subject: [PATCH] add interrupt channels, waker

---
 embassy-stm32f4/src/lib.rs   | 49 ++++++++++++++++++++++++++++++++++++
 embassy-stm32f4/src/uarte.rs |  5 ++--
 2 files changed, 51 insertions(+), 3 deletions(-)

diff --git a/embassy-stm32f4/src/lib.rs b/embassy-stm32f4/src/lib.rs
index fc411088..f2304c94 100644
--- a/embassy-stm32f4/src/lib.rs
+++ b/embassy-stm32f4/src/lib.rs
@@ -307,6 +307,55 @@ compile_error!(
 pub use stm32f4xx_hal as hal;
 pub use stm32f4xx_hal::stm32 as pac;
 
+/// Creates a new interrupt waking a [`Waker`].
+///
+/// As this interrupt will be declared in this macro, it can't be used for anything else.
+///
+/// # Examples
+///
+/// This macro is useful for implementing [`Future::poll`]:
+///
+/// ```
+/// fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
+///     if self.is_ready() {
+///         Poll::Ready(())
+///     } else {
+///         waker_interrupt!(TIM2, cx.waker().clone());
+///         Poll::Pending
+///     }
+/// }
+/// ```
+///
+/// [`Waker`]: core::task::Waker
+/// [`Future::poll`]: core::future::Future::poll
+macro_rules! waker_interrupt {
+    ($INT:ident, $waker:expr) => {{
+        use core::sync::atomic::{self, Ordering};
+        use stm32f4xx_hal::pac::{interrupt, Interrupt, NVIC};
+
+        static mut WAKER: Option<Waker> = None;
+
+        #[interrupt]
+        fn $INT() {
+            // Safety: This context is disabled while the lower priority context accesses WAKER
+            if let Some(waker) = unsafe { WAKER.as_ref() } {
+                waker.wake_by_ref();
+
+                NVIC::mask(Interrupt::$INT);
+            }
+        }
+
+        NVIC::mask(Interrupt::$INT);
+        atomic::compiler_fence(Ordering::Acquire);
+        // Safety: The other relevant context, the interrupt, is disabled
+        unsafe { WAKER = Some($waker) }
+        NVIC::unpend(Interrupt::$INT);
+        atomic::compiler_fence(Ordering::Release);
+        // Safety: This is the end of a mask-based critical section
+        unsafe { NVIC::unmask(Interrupt::$INT) }
+    }};
+}
+
 // This mod MUST go first, so that the others see its macros.
 pub(crate) mod fmt;
 
diff --git a/embassy-stm32f4/src/uarte.rs b/embassy-stm32f4/src/uarte.rs
index 222d4ba4..2d0fd9af 100644
--- a/embassy-stm32f4/src/uarte.rs
+++ b/embassy-stm32f4/src/uarte.rs
@@ -554,13 +554,12 @@ pub trait Instance: Deref<Target = uarte0::RegisterBlock> + Sized + private::Sea
 }
 
 #[interrupt]
-unsafe fn UARTE0_UART0() {
+unsafe fn DMA2_CHANNEL2() {
     interrupt::free(|cs| UARTE0::get_state(cs).as_mut().unwrap().on_interrupt());
 }
 
-#[cfg(any(feature = "52833", feature = "52840", feature = "9160"))]
 #[interrupt]
-unsafe fn UARTE1() {
+unsafe fn DMA2_CHANNEL7() {
     interrupt::free(|cs| UARTE1::get_state(cs).as_mut().unwrap().on_interrupt());
 }