128 lines
3.9 KiB
Rust
128 lines
3.9 KiB
Rust
use core::arch::asm;
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use core::marker::PhantomData;
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use core::sync::atomic::{compiler_fence, Ordering};
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use cortex_m::peripheral::SCB;
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use embassy_executor::*;
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use crate::interrupt;
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use crate::rcc::low_power_ready;
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use crate::time_driver::{get_driver, RtcDriver};
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const THREAD_PENDER: usize = usize::MAX;
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use crate::rtc::Rtc;
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static mut EXECUTOR: Option<Executor> = None;
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foreach_interrupt! {
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(RTC, rtc, $block:ident, WKUP, $irq:ident) => {
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#[interrupt]
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unsafe fn $irq() {
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EXECUTOR.as_mut().unwrap().on_wakeup_irq();
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}
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};
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}
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#[allow(dead_code)]
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pub(crate) unsafe fn on_wakeup_irq() {
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EXECUTOR.as_mut().unwrap().on_wakeup_irq();
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}
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pub fn stop_with_rtc(rtc: &'static Rtc) {
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unsafe { EXECUTOR.as_mut().unwrap() }.stop_with_rtc(rtc)
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}
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/// Thread mode executor, using WFE/SEV.
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///
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/// This is the simplest and most common kind of executor. It runs on
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/// thread mode (at the lowest priority level), and uses the `WFE` ARM instruction
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/// to sleep when it has no more work to do. When a task is woken, a `SEV` instruction
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/// is executed, to make the `WFE` exit from sleep and poll the task.
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///
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/// This executor allows for ultra low power consumption for chips where `WFE`
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/// triggers low-power sleep without extra steps. If your chip requires extra steps,
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/// you may use [`raw::Executor`] directly to program custom behavior.
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pub struct Executor {
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inner: raw::Executor,
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not_send: PhantomData<*mut ()>,
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scb: SCB,
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time_driver: &'static RtcDriver,
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}
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impl Executor {
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/// Create a new Executor.
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pub fn take() -> &'static mut Self {
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unsafe {
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assert!(EXECUTOR.is_none());
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EXECUTOR = Some(Self {
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inner: raw::Executor::new(THREAD_PENDER as *mut ()),
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not_send: PhantomData,
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scb: cortex_m::Peripherals::steal().SCB,
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time_driver: get_driver(),
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});
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EXECUTOR.as_mut().unwrap()
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}
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}
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unsafe fn on_wakeup_irq(&mut self) {
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self.time_driver.resume_time();
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trace!("low power: resume");
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}
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pub(self) fn stop_with_rtc(&mut self, rtc: &'static Rtc) {
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self.time_driver.set_rtc(rtc);
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rtc.enable_wakeup_line();
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trace!("low power: stop with rtc configured");
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}
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fn configure_pwr(&mut self) {
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self.scb.clear_sleepdeep();
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compiler_fence(Ordering::SeqCst);
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if !low_power_ready() {
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trace!("low power: not ready to stop");
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} else if self.time_driver.pause_time().is_err() {
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trace!("low power: failed to pause time");
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} else {
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trace!("low power: stop");
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self.scb.set_sleepdeep();
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}
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}
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/// Run the executor.
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///
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/// The `init` closure is called with a [`Spawner`] that spawns tasks on
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/// this executor. Use it to spawn the initial task(s). After `init` returns,
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/// the executor starts running the tasks.
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///
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/// To spawn more tasks later, you may keep copies of the [`Spawner`] (it is `Copy`),
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/// for example by passing it as an argument to the initial tasks.
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///
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/// This function requires `&'static mut self`. This means you have to store the
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/// Executor instance in a place where it'll live forever and grants you mutable
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/// access. There's a few ways to do this:
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///
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/// - a [StaticCell](https://docs.rs/static_cell/latest/static_cell/) (safe)
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/// - a `static mut` (unsafe)
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/// - a local variable in a function you know never returns (like `fn main() -> !`), upgrading its lifetime with `transmute`. (unsafe)
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///
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/// This function never returns.
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pub fn run(&'static mut self, init: impl FnOnce(Spawner)) -> ! {
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init(unsafe { EXECUTOR.as_mut().unwrap() }.inner.spawner());
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loop {
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unsafe {
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EXECUTOR.as_mut().unwrap().inner.poll();
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self.configure_pwr();
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asm!("wfe");
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};
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}
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}
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}
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