84 lines
2.2 KiB
Rust
84 lines
2.2 KiB
Rust
use core::cell::UnsafeCell;
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use core::marker::{PhantomData, PhantomPinned};
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use core::pin::Pin;
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use core::sync::atomic::{compiler_fence, Ordering};
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use embassy::interrupt::{Interrupt, InterruptExt};
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pub trait PeripheralState {
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type Interrupt: Interrupt;
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fn on_interrupt(&mut self);
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}
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pub struct PeripheralMutex<S: PeripheralState> {
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state: UnsafeCell<S>,
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irq_setup_done: bool,
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irq: S::Interrupt,
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_not_send: PhantomData<*mut ()>,
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_pinned: PhantomPinned,
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}
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impl<S: PeripheralState> PeripheralMutex<S> {
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pub fn new(state: S, irq: S::Interrupt) -> Self {
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Self {
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irq,
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irq_setup_done: false,
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state: UnsafeCell::new(state),
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_not_send: PhantomData,
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_pinned: PhantomPinned,
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}
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}
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pub fn register_interrupt(self: Pin<&mut Self>) {
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let this = unsafe { self.get_unchecked_mut() };
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if this.irq_setup_done {
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return;
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}
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this.irq.disable();
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compiler_fence(Ordering::SeqCst);
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this.irq.set_handler(|p| {
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// Safety: it's OK to get a &mut to the state, since
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// - We're in the IRQ, no one else can't preempt us
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// - We can't have preempted a with() call because the irq is disabled during it.
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let state = unsafe { &mut *(p as *mut S) };
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state.on_interrupt();
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});
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this.irq
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.set_handler_context((&mut this.state) as *mut _ as *mut ());
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compiler_fence(Ordering::SeqCst);
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this.irq.enable();
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this.irq_setup_done = true;
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}
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pub fn with<R>(self: Pin<&mut Self>, f: impl FnOnce(&mut S, &mut S::Interrupt) -> R) -> R {
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let this = unsafe { self.get_unchecked_mut() };
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this.irq.disable();
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compiler_fence(Ordering::SeqCst);
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// Safety: it's OK to get a &mut to the state, since the irq is disabled.
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let state = unsafe { &mut *this.state.get() };
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let r = f(state, &mut this.irq);
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compiler_fence(Ordering::SeqCst);
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this.irq.enable();
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r
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}
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}
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impl<S: PeripheralState> Drop for PeripheralMutex<S> {
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fn drop(&mut self) {
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self.irq.disable();
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self.irq.remove_handler();
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}
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}
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