diff --git a/embassy/src/lib.rs b/embassy/src/lib.rs index 4fa37a55c..74c69b541 100644 --- a/embassy/src/lib.rs +++ b/embassy/src/lib.rs @@ -2,6 +2,8 @@ #![feature(generic_associated_types)] #![feature(const_fn)] #![feature(const_fn_fn_ptr_basics)] +#![feature(const_in_array_repeat_expressions)] +#![feature(const_option)] // This mod MUST go first, so that the others see its macros. pub(crate) mod fmt; diff --git a/embassy/src/util/signal.rs b/embassy/src/util/signal.rs index 8e778d1e3..2c9c52f1e 100644 --- a/embassy/src/util/signal.rs +++ b/embassy/src/util/signal.rs @@ -1,8 +1,13 @@ +use crate::executor; use crate::fmt::panic; +use crate::interrupt::OwnedInterrupt; use core::cell::UnsafeCell; use core::future::Future; use core::mem; +use core::ptr; use core::task::{Context, Poll, Waker}; +use cortex_m::peripheral::NVIC; +use cortex_m::peripheral::{scb, SCB}; pub struct Signal { state: UnsafeCell>, @@ -67,3 +72,66 @@ impl Signal { cortex_m::interrupt::free(|_| matches!(unsafe { &*self.state.get() }, State::Signaled(_))) } } + +struct NrWrap(u8); +unsafe impl cortex_m::interrupt::Nr for NrWrap { + fn nr(&self) -> u8 { + self.0 + } +} + +pub struct InterruptFuture<'a, I: OwnedInterrupt> { + interrupt: &'a mut I, +} + +impl<'a, I: OwnedInterrupt> Drop for InterruptFuture<'a, I> { + fn drop(&mut self) { + self.interrupt.disable(); + self.interrupt.remove_handler(); + } +} + +impl<'a, I: OwnedInterrupt> InterruptFuture<'a, I> { + pub fn new(interrupt: &'a mut I) -> Self { + interrupt.disable(); + interrupt.set_handler(Self::interrupt_handler, ptr::null_mut()); + interrupt.unpend(); + interrupt.enable(); + + Self { + interrupt: interrupt, + } + } + + unsafe fn interrupt_handler(ctx: *mut ()) { + let irq = match SCB::vect_active() { + scb::VectActive::Interrupt { irqn } => irqn, + _ => unreachable!(), + }; + + if ctx as *const _ != ptr::null() { + executor::raw::wake_task(ptr::NonNull::new_unchecked(ctx)); + } + + NVIC::mask(NrWrap(irq)); + } +} + +impl<'a, I: OwnedInterrupt> Unpin for InterruptFuture<'a, I> {} + +impl<'a, I: OwnedInterrupt> Future for InterruptFuture<'a, I> { + type Output = (); + + fn poll(self: core::pin::Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<()> { + let s = unsafe { self.get_unchecked_mut() }; + s.interrupt.set_handler( + Self::interrupt_handler, + executor::raw::task_from_waker(&cx.waker()).cast().as_ptr(), + ); + if s.interrupt.is_enabled() { + Poll::Pending + } else { + Poll::Ready(()) + } + } +}