59 lines
1.7 KiB
Rust
59 lines
1.7 KiB
Rust
//! Timer queue implementation
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//!
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//! This module defines the interface a timer queue needs to implement to power the `embassy_time` module.
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//!
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//! # Implementing a timer queue
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//!
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//! - Define a struct `MyTimerQueue`
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//! - Implement [`TimerQueue`] for it
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//! - Register it as the global timer queue with [`timer_queue_impl`](crate::timer_queue_impl).
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//!
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//! # Linkage details
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//!
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//! Check the documentation of the [`driver`](crate::driver) module for more information.
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//!
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//! Similarly to driver, if there is none or multiple timer queues in the crate tree, linking will fail.
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//!
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//! # Example
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//!
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//! ```
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//! use core::task::Waker;
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//!
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//! use embassy_time::Instant;
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//! use embassy_time::queue::{TimerQueue};
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//!
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//! struct MyTimerQueue{}; // not public!
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//! embassy_time::timer_queue_impl!(static QUEUE: MyTimerQueue = MyTimerQueue{});
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//!
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//! impl TimerQueue for MyTimerQueue {
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//! fn schedule_wake(&'static self, at: Instant, waker: &Waker) {
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//! todo!()
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//! }
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//! }
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//! ```
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use core::task::Waker;
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use crate::Instant;
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/// Timer queue
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pub trait TimerQueue {
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/// Schedules a waker in the queue to be awoken at moment `at`.
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/// If this moment is in the past, the waker might be awoken immediately.
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fn schedule_wake(&'static self, at: Instant, waker: &Waker);
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}
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/// Set the TimerQueue implementation.
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///
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/// See the module documentation for an example.
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#[macro_export]
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macro_rules! timer_queue_impl {
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(static $name:ident: $t: ty = $val:expr) => {
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static $name: $t = $val;
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#[no_mangle]
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fn _embassy_time_schedule_wake(at: $crate::Instant, waker: &core::task::Waker) {
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<$t as $crate::queue::TimerQueue>::schedule_wake(&$name, at, waker);
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}
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};
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}
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