Remove the non-specific thread-mode executor
This commit is contained in:
parent
4c4b12c307
commit
986a63ebb8
7 changed files with 369 additions and 276 deletions
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@ -1,122 +1,236 @@
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#[cfg(feature = "executor-thread")]
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pub use thread::*;
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const THREAD_PENDER: usize = usize::MAX;
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use crate::raw::PenderContext;
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#[cfg(feature = "executor-interrupt")]
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/// # Safety
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///
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/// `irq` must be a valid interrupt request number
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unsafe fn nvic_pend(irq: u16) {
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use cortex_m::interrupt::InterruptNumber;
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#[derive(Clone, Copy)]
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struct Irq(u16);
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unsafe impl InterruptNumber for Irq {
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fn number(self) -> u16 {
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self.0
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}
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}
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let irq = Irq(irq);
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// STIR is faster, but is only available in v7 and higher.
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#[cfg(not(armv6m))]
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{
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let mut nvic: cortex_m::peripheral::NVIC = unsafe { core::mem::transmute(()) };
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nvic.request(irq);
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}
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#[cfg(armv6m)]
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cortex_m::peripheral::NVIC::pend(irq);
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}
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#[cfg(all(feature = "executor-thread", feature = "executor-interrupt"))]
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#[export_name = "__pender"]
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fn __pender(context: PenderContext) {
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#[cfg(any(feature = "executor-thread", feature = "executor-interrupt"))]
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fn __pender(context: crate::raw::PenderContext) {
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unsafe {
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let context: usize = core::mem::transmute(context);
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// Safety: `context` is either `usize::MAX` created by `Executor::run`, or a valid interrupt
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// request number given to `InterruptExecutor::start`.
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if context as usize == usize::MAX {
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core::arch::asm!("sev")
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} else {
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nvic_pend(context as u16)
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let context: usize = core::mem::transmute(context);
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#[cfg(feature = "executor-thread")]
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if context == THREAD_PENDER {
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core::arch::asm!("sev");
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return;
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}
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#[cfg(feature = "executor-interrupt")]
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{
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use cortex_m::interrupt::InterruptNumber;
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use cortex_m::peripheral::NVIC;
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#[derive(Clone, Copy)]
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struct Irq(u16);
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unsafe impl InterruptNumber for Irq {
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fn number(self) -> u16 {
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self.0
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}
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}
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let irq = Irq(context as u16);
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// STIR is faster, but is only available in v7 and higher.
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#[cfg(not(armv6m))]
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{
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let mut nvic: NVIC = core::mem::transmute(());
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nvic.request(irq);
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}
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#[cfg(armv6m)]
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NVIC::pend(irq);
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}
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}
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}
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#[cfg(all(feature = "executor-thread", not(feature = "executor-interrupt")))]
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#[export_name = "__pender"]
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fn __pender(_context: PenderContext) {
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unsafe { core::arch::asm!("sev") }
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}
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#[cfg(all(not(feature = "executor-thread"), feature = "executor-interrupt"))]
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#[export_name = "__pender"]
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fn __pender(context: PenderContext) {
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unsafe {
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let context: usize = core::mem::transmute(context);
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// Safety: `context` is the same value we passed to `InterruptExecutor::start`, which must
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// be a valid interrupt request number.
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nvic_pend(context as u16)
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}
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}
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#[cfg(feature = "executor-thread")]
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pub use thread::*;
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#[cfg(feature = "executor-thread")]
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mod thread {
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use core::arch::asm;
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use core::marker::PhantomData;
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#[cfg(feature = "nightly")]
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pub use embassy_macros::main_cortex_m as main;
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use crate::raw::PenderContext;
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use crate::thread::ThreadContext;
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use crate::arch::THREAD_PENDER;
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use crate::{raw, Spawner};
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/// TODO
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// Name pending
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#[derive(Default)] // Default enables Executor::new
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pub struct Context;
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impl ThreadContext for Context {
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fn context(&self) -> PenderContext {
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unsafe { core::mem::transmute(usize::MAX) }
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}
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fn wait(&mut self) {
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unsafe { core::arch::asm!("wfe") }
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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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}
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/// TODO
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// Type alias for backwards compatibility
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pub type Executor = crate::thread::ThreadModeExecutor<Context>;
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impl Executor {
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/// Create a new Executor.
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pub fn new() -> Self {
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Self {
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inner: raw::Executor::new(unsafe { core::mem::transmute(THREAD_PENDER) }),
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not_send: PhantomData,
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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(self.inner.spawner());
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loop {
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unsafe {
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self.inner.poll();
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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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}
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#[cfg(feature = "executor-interrupt")]
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pub use interrupt::*;
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#[cfg(feature = "executor-interrupt")]
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mod interrupt {
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use core::cell::UnsafeCell;
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use core::mem::MaybeUninit;
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use atomic_polyfill::{AtomicBool, Ordering};
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use cortex_m::interrupt::InterruptNumber;
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use cortex_m::peripheral::NVIC;
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use crate::interrupt::InterruptContext;
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use crate::raw::PenderContext;
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use crate::raw;
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impl<T> InterruptContext for T
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where
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T: InterruptNumber,
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{
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fn context(&self) -> PenderContext {
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unsafe { core::mem::transmute(self.number() as usize) }
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}
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fn enable(&self) {
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unsafe { NVIC::unmask(*self) }
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}
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/// Interrupt mode executor.
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///
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/// This executor runs tasks in interrupt mode. The interrupt handler is set up
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/// to poll tasks, and when a task is woken the interrupt is pended from software.
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///
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/// This allows running async tasks at a priority higher than thread mode. One
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/// use case is to leave thread mode free for non-async tasks. Another use case is
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/// to run multiple executors: one in thread mode for low priority tasks and another in
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/// interrupt mode for higher priority tasks. Higher priority tasks will preempt lower
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/// priority ones.
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///
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/// It is even possible to run multiple interrupt mode executors at different priorities,
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/// by assigning different priorities to the interrupts. For an example on how to do this,
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/// See the 'multiprio' example for 'embassy-nrf'.
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///
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/// To use it, you have to pick an interrupt that won't be used by the hardware.
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/// Some chips reserve some interrupts for this purpose, sometimes named "software interrupts" (SWI).
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/// If this is not the case, you may use an interrupt from any unused peripheral.
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///
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/// It is somewhat more complex to use, it's recommended to use the thread-mode
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/// [`Executor`] instead, if it works for your use case.
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pub struct InterruptExecutor {
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started: AtomicBool,
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executor: UnsafeCell<MaybeUninit<raw::Executor>>,
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}
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/// TODO
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// Type alias for backwards compatibility
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pub type InterruptExecutor = crate::interrupt::InterruptModeExecutor;
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unsafe impl Send for InterruptExecutor {}
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unsafe impl Sync for InterruptExecutor {}
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impl InterruptExecutor {
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/// Create a new, not started `InterruptExecutor`.
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#[inline]
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pub const fn new() -> Self {
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Self {
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started: AtomicBool::new(false),
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executor: UnsafeCell::new(MaybeUninit::uninit()),
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}
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}
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/// Executor interrupt callback.
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///
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/// # Safety
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///
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/// You MUST call this from the interrupt handler, and from nowhere else.
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pub unsafe fn on_interrupt(&'static self) {
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let executor = unsafe { (&*self.executor.get()).assume_init_ref() };
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executor.poll();
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}
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/// Start the executor.
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///
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/// This initializes the executor, enables the interrupt, and returns.
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/// The executor keeps running in the background through the interrupt.
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///
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/// This returns a [`SendSpawner`] you can use to spawn tasks on it. A [`SendSpawner`]
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/// is returned instead of a [`Spawner`](embassy_executor::Spawner) because the executor effectively runs in a
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/// different "thread" (the interrupt), so spawning tasks on it is effectively
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/// sending them.
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///
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/// To obtain a [`Spawner`](embassy_executor::Spawner) for this executor, use [`Spawner::for_current_executor()`](embassy_executor::Spawner::for_current_executor()) from
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/// a task running in it.
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///
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/// # Interrupt requirements
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///
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/// You must write the interrupt handler yourself, and make it call [`on_interrupt()`](Self::on_interrupt).
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///
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/// This method already enables (unmasks) the interrupt, you must NOT do it yourself.
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///
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/// You must set the interrupt priority before calling this method. You MUST NOT
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/// do it after.
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///
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pub fn start(&'static self, irq: impl InterruptNumber) -> crate::SendSpawner {
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if self
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.started
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.compare_exchange(false, true, Ordering::Acquire, Ordering::Relaxed)
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.is_err()
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{
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panic!("InterruptExecutor::start() called multiple times on the same executor.");
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}
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unsafe {
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let context = core::mem::transmute(irq.number() as usize);
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(&mut *self.executor.get())
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.as_mut_ptr()
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.write(raw::Executor::new(context))
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}
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let executor = unsafe { (&*self.executor.get()).assume_init_ref() };
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unsafe { NVIC::unmask(irq) }
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executor.spawner().make_send()
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}
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/// Get a SendSpawner for this executor
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///
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/// This returns a [`SendSpawner`] you can use to spawn tasks on this
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/// executor.
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///
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/// This MUST only be called on an executor that has already been spawned.
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/// The function will panic otherwise.
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pub fn spawner(&'static self) -> crate::SendSpawner {
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if !self.started.load(Ordering::Acquire) {
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panic!("InterruptExecutor::spawner() called on uninitialized executor.");
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}
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let executor = unsafe { (&*self.executor.get()).assume_init_ref() };
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executor.spawner().make_send()
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}
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}
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}
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@ -5,53 +5,77 @@ compile_error!("`executor-interrupt` is not supported with `arch-riscv32`.");
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pub use thread::*;
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#[cfg(feature = "executor-thread")]
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mod thread {
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use core::marker::PhantomData;
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use core::sync::atomic::{AtomicBool, Ordering};
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#[cfg(feature = "nightly")]
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pub use embassy_macros::main_riscv as main;
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use crate::raw::PenderContext;
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use crate::thread::ThreadContext;
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use crate::{raw, Spawner};
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/// global atomic used to keep track of whether there is work to do since sev() is not available on RISCV
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static SIGNAL_WORK_THREAD_MODE: AtomicBool = AtomicBool::new(false);
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#[export_name = "__pender"]
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fn __thread_mode_pender(_context: PenderContext) {
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fn __thread_mode_pender(_context: crate::raw::PenderContext) {
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SIGNAL_WORK_THREAD_MODE.store(true, Ordering::SeqCst);
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}
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/// TODO
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// Name pending
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#[derive(Default)] // Default enables Executor::new
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pub struct Context;
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impl ThreadContext for Context {
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fn context(&self) -> PenderContext {
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unsafe { core::mem::transmute(0) }
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}
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fn wait(&mut self) {
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// We do not care about race conditions between the load and store operations,
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// interrupts will only set this value to true.
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critical_section::with(|_| {
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// if there is work to do, loop back to polling
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// TODO can we relax this?
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if SIGNAL_WORK_THREAD_MODE.load(Ordering::SeqCst) {
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SIGNAL_WORK_THREAD_MODE.store(false, Ordering::SeqCst);
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}
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// if not, wait for interrupt
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else {
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unsafe {
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core::arch::asm!("wfi");
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}
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}
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});
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// if an interrupt occurred while waiting, it will be serviced here
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}
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/// RISCV32 Executor
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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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}
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/// TODO
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// Type alias for backwards compatibility
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pub type Executor = crate::thread::ThreadModeExecutor<Context>;
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impl Executor {
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/// Create a new Executor.
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pub fn new() -> Self {
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Self {
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inner: raw::Executor::new(unsafe { core::mem::transmute(0) }),
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not_send: PhantomData,
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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(self.inner.spawner());
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loop {
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unsafe {
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self.inner.poll();
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// we do not care about race conditions between the load and store operations, interrupts
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//will only set this value to true.
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critical_section::with(|_| {
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// if there is work to do, loop back to polling
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// TODO can we relax this?
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if SIGNAL_WORK_THREAD_MODE.load(Ordering::SeqCst) {
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SIGNAL_WORK_THREAD_MODE.store(false, Ordering::SeqCst);
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}
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// if not, wait for interrupt
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else {
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core::arch::asm!("wfi");
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}
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});
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// if an interrupt occurred while waiting, it will be serviced here
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}
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}
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}
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}
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}
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|
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@ -5,42 +5,64 @@ compile_error!("`executor-interrupt` is not supported with `arch-std`.");
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pub use thread::*;
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#[cfg(feature = "executor-thread")]
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mod thread {
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use std::marker::PhantomData;
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use std::sync::{Condvar, Mutex};
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#[cfg(feature = "nightly")]
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pub use embassy_macros::main_std as main;
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use crate::raw::PenderContext;
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use crate::thread::ThreadContext;
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use crate::{raw, Spawner};
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/// TODO
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// Name pending
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pub struct Context {
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#[export_name = "__pender"]
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fn __pender(context: crate::raw::PenderContext) {
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let signaler: &'static Signaler = unsafe { std::mem::transmute(context) };
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signaler.signal()
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}
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/// Single-threaded std-based executor.
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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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signaler: &'static Signaler,
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}
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impl Default for Context {
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fn default() -> Self {
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impl Executor {
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/// Create a new Executor.
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pub fn new() -> Self {
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||||
let signaler = &*Box::leak(Box::new(Signaler::new()));
|
||||
Self {
|
||||
signaler: &*Box::leak(Box::new(Signaler::new())),
|
||||
inner: raw::Executor::new(unsafe { std::mem::transmute(signaler) }),
|
||||
not_send: PhantomData,
|
||||
signaler,
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
impl ThreadContext for Context {
|
||||
fn context(&self) -> PenderContext {
|
||||
unsafe { core::mem::transmute(self.signaler) }
|
||||
/// Run the executor.
|
||||
///
|
||||
/// The `init` closure is called with a [`Spawner`] that spawns tasks on
|
||||
/// this executor. Use it to spawn the initial task(s). After `init` returns,
|
||||
/// the executor starts running the tasks.
|
||||
///
|
||||
/// To spawn more tasks later, you may keep copies of the [`Spawner`] (it is `Copy`),
|
||||
/// for example by passing it as an argument to the initial tasks.
|
||||
///
|
||||
/// This function requires `&'static mut self`. This means you have to store the
|
||||
/// Executor instance in a place where it'll live forever and grants you mutable
|
||||
/// access. There's a few ways to do this:
|
||||
///
|
||||
/// - a [StaticCell](https://docs.rs/static_cell/latest/static_cell/) (safe)
|
||||
/// - a `static mut` (unsafe)
|
||||
/// - a local variable in a function you know never returns (like `fn main() -> !`), upgrading its lifetime with `transmute`. (unsafe)
|
||||
///
|
||||
/// This function never returns.
|
||||
pub fn run(&'static mut self, init: impl FnOnce(Spawner)) -> ! {
|
||||
init(self.inner.spawner());
|
||||
|
||||
loop {
|
||||
unsafe { self.inner.poll() };
|
||||
self.signaler.wait()
|
||||
}
|
||||
}
|
||||
|
||||
fn wait(&mut self) {
|
||||
self.signaler.wait()
|
||||
}
|
||||
}
|
||||
|
||||
#[export_name = "__pender"]
|
||||
fn __pender(context: PenderContext) {
|
||||
let signaler: &'static Signaler = unsafe { std::mem::transmute(context) };
|
||||
signaler.signal()
|
||||
}
|
||||
|
||||
struct Signaler {
|
||||
|
@ -70,8 +92,4 @@ mod thread {
|
|||
self.condvar.notify_one();
|
||||
}
|
||||
}
|
||||
|
||||
/// TODO
|
||||
// Type alias for backwards compatibility
|
||||
pub type Executor = crate::thread::ThreadModeExecutor<Context>;
|
||||
}
|
||||
|
|
|
@ -8,56 +8,80 @@ mod thread {
|
|||
use core::marker::PhantomData;
|
||||
use core::sync::atomic::{AtomicBool, Ordering};
|
||||
|
||||
use crate::raw::PenderContext;
|
||||
use crate::thread::ThreadContext;
|
||||
use crate::{raw, Spawner};
|
||||
|
||||
/// global atomic used to keep track of whether there is work to do since sev() is not available on Xtensa
|
||||
static SIGNAL_WORK_THREAD_MODE: AtomicBool = AtomicBool::new(false);
|
||||
|
||||
#[export_name = "__thread_mode_pender"]
|
||||
fn __thread_mode_pender(_context: PenderContext) {
|
||||
fn __thread_mode_pender(_context: crate::raw::PenderContext) {
|
||||
SIGNAL_WORK_THREAD_MODE.store(true, Ordering::SeqCst);
|
||||
}
|
||||
|
||||
/// TODO
|
||||
// Name pending
|
||||
#[derive(Default)] // Default enables Executor::new
|
||||
pub struct Context;
|
||||
/// Xtensa Executor
|
||||
pub struct Executor {
|
||||
inner: raw::Executor,
|
||||
not_send: PhantomData<*mut ()>,
|
||||
}
|
||||
|
||||
impl ThreadContext for Context {
|
||||
fn context(&self) -> PenderContext {
|
||||
unsafe { core::mem::transmute(0) }
|
||||
impl Executor {
|
||||
/// Create a new Executor.
|
||||
pub fn new() -> Self {
|
||||
Self {
|
||||
inner: raw::Executor::new(unsafe { core::mem::transmute(0) }),
|
||||
not_send: PhantomData,
|
||||
}
|
||||
}
|
||||
|
||||
fn wait(&mut self) {
|
||||
unsafe {
|
||||
// Manual critical section implementation that only masks interrupts handlers.
|
||||
// We must not acquire the cross-core on dual-core systems because that would
|
||||
// prevent the other core from doing useful work while this core is sleeping.
|
||||
let token: critical_section::RawRestoreState;
|
||||
core::arch::asm!("rsil {0}, 5", out(reg) token);
|
||||
/// Run the executor.
|
||||
///
|
||||
/// The `init` closure is called with a [`Spawner`] that spawns tasks on
|
||||
/// this executor. Use it to spawn the initial task(s). After `init` returns,
|
||||
/// the executor starts running the tasks.
|
||||
///
|
||||
/// To spawn more tasks later, you may keep copies of the [`Spawner`] (it is `Copy`),
|
||||
/// for example by passing it as an argument to the initial tasks.
|
||||
///
|
||||
/// This function requires `&'static mut self`. This means you have to store the
|
||||
/// Executor instance in a place where it'll live forever and grants you mutable
|
||||
/// access. There's a few ways to do this:
|
||||
///
|
||||
/// - a [StaticCell](https://docs.rs/static_cell/latest/static_cell/) (safe)
|
||||
/// - a `static mut` (unsafe)
|
||||
/// - a local variable in a function you know never returns (like `fn main() -> !`), upgrading its lifetime with `transmute`. (unsafe)
|
||||
///
|
||||
/// This function never returns.
|
||||
pub fn run(&'static mut self, init: impl FnOnce(Spawner)) -> ! {
|
||||
init(self.inner.spawner());
|
||||
|
||||
// we do not care about race conditions between the load and store operations,
|
||||
// interrupts will only set this value to true.
|
||||
// if there is work to do, loop back to polling
|
||||
if SIGNAL_WORK_THREAD_MODE.load(Ordering::SeqCst) {
|
||||
SIGNAL_WORK_THREAD_MODE.store(false, Ordering::SeqCst);
|
||||
loop {
|
||||
unsafe {
|
||||
self.inner.poll();
|
||||
|
||||
core::arch::asm!(
|
||||
"wsr.ps {0}",
|
||||
"rsync", in(reg) token)
|
||||
} else {
|
||||
// waiti sets the PS.INTLEVEL when slipping into sleep
|
||||
// because critical sections in Xtensa are implemented via increasing
|
||||
// PS.INTLEVEL the critical section ends here
|
||||
// take care not add code after `waiti` if it needs to be inside the CS
|
||||
core::arch::asm!("waiti 0"); // critical section ends here
|
||||
// Manual critical section implementation that only masks interrupts handlers.
|
||||
// We must not acquire the cross-core on dual-core systems because that would
|
||||
// prevent the other core from doing useful work while this core is sleeping.
|
||||
let token: critical_section::RawRestoreState;
|
||||
core::arch::asm!("rsil {0}, 5", out(reg) token);
|
||||
|
||||
// we do not care about race conditions between the load and store operations, interrupts
|
||||
// will only set this value to true.
|
||||
// if there is work to do, loop back to polling
|
||||
if SIGNAL_WORK_THREAD_MODE.load(Ordering::SeqCst) {
|
||||
SIGNAL_WORK_THREAD_MODE.store(false, Ordering::SeqCst);
|
||||
|
||||
core::arch::asm!(
|
||||
"wsr.ps {0}",
|
||||
"rsync", in(reg) token)
|
||||
} else {
|
||||
// waiti sets the PS.INTLEVEL when slipping into sleep
|
||||
// because critical sections in Xtensa are implemented via increasing
|
||||
// PS.INTLEVEL the critical section ends here
|
||||
// take care not add code after `waiti` if it needs to be inside the CS
|
||||
core::arch::asm!("waiti 0"); // critical section ends here
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
/// TODO
|
||||
// Type alias for backwards compatibility
|
||||
pub type Executor = crate::thread::ThreadModeExecutor<Context>;
|
||||
}
|
||||
|
|
|
@ -41,7 +41,7 @@ pub trait InterruptContext {
|
|||
/// If this is not the case, you may use an interrupt from any unused peripheral.
|
||||
///
|
||||
/// It is somewhat more complex to use, it's recommended to use the
|
||||
/// [`crate::thread::ThreadModeExecutor`] instead, if it works for your use case.
|
||||
/// thread-mode executor instead, if it works for your use case.
|
||||
pub struct InterruptModeExecutor {
|
||||
started: AtomicBool,
|
||||
executor: UnsafeCell<MaybeUninit<raw::Executor>>,
|
||||
|
|
|
@ -39,8 +39,8 @@ pub mod raw;
|
|||
|
||||
#[cfg(feature = "executor-interrupt")]
|
||||
pub mod interrupt;
|
||||
#[cfg(feature = "executor-thread")]
|
||||
pub mod thread;
|
||||
#[cfg(feature = "executor-interrupt")]
|
||||
pub use interrupt::*;
|
||||
|
||||
mod spawner;
|
||||
pub use spawner::*;
|
||||
|
|
|
@ -1,87 +0,0 @@
|
|||
//! Thread-mode executor.
|
||||
|
||||
use core::marker::PhantomData;
|
||||
|
||||
use crate::raw::{self, PenderContext};
|
||||
use crate::Spawner;
|
||||
|
||||
/// Architecture-specific interface for a thread-mode executor. This trait describes what the
|
||||
/// executor should do when idle, and what data should be passed to its pender.
|
||||
// TODO: Name pending
|
||||
pub trait ThreadContext: Sized {
|
||||
/// A pointer-sized piece of data that is passed to the pender function.
|
||||
///
|
||||
/// For example, on multi-core systems, this can be used to store the ID of the core that
|
||||
/// should be woken up.
|
||||
fn context(&self) -> PenderContext;
|
||||
|
||||
/// Waits for the executor to be waken.
|
||||
///
|
||||
/// While it is valid for this function can be empty, it is recommended to use a WFE instruction
|
||||
/// or equivalent to let the CPU sleep.
|
||||
fn wait(&mut self);
|
||||
}
|
||||
|
||||
/// Thread mode executor, using WFE/SEV.
|
||||
///
|
||||
/// This is the simplest and most common kind of executor. It runs on
|
||||
/// thread mode (at the lowest priority level), and uses the `WFE` ARM instruction
|
||||
/// to sleep when it has no more work to do. When a task is woken, a `SEV` instruction
|
||||
/// is executed, to make the `WFE` exit from sleep and poll the task.
|
||||
///
|
||||
/// This executor allows for ultra low power consumption for chips where `WFE`
|
||||
/// triggers low-power sleep without extra steps. If your chip requires extra steps,
|
||||
/// you may use [`raw::Executor`] directly to program custom behavior.
|
||||
pub struct ThreadModeExecutor<C: ThreadContext> {
|
||||
inner: raw::Executor,
|
||||
context: C,
|
||||
not_send: PhantomData<*mut ()>,
|
||||
}
|
||||
|
||||
impl<C: ThreadContext> ThreadModeExecutor<C> {
|
||||
/// Create a new Executor.
|
||||
pub fn new() -> Self
|
||||
where
|
||||
C: Default,
|
||||
{
|
||||
Self::with_context(C::default())
|
||||
}
|
||||
|
||||
/// Create a new Executor using the given thread context.
|
||||
pub fn with_context(context: C) -> Self {
|
||||
Self {
|
||||
inner: raw::Executor::new(context.context()),
|
||||
context,
|
||||
not_send: PhantomData,
|
||||
}
|
||||
}
|
||||
|
||||
/// Run the executor.
|
||||
///
|
||||
/// The `init` closure is called with a [`Spawner`] that spawns tasks on
|
||||
/// this executor. Use it to spawn the initial task(s). After `init` returns,
|
||||
/// the executor starts running the tasks.
|
||||
///
|
||||
/// To spawn more tasks later, you may keep copies of the [`Spawner`] (it is `Copy`),
|
||||
/// for example by passing it as an argument to the initial tasks.
|
||||
///
|
||||
/// This function requires `&'static mut self`. This means you have to store the
|
||||
/// Executor instance in a place where it'll live forever and grants you mutable
|
||||
/// access. There's a few ways to do this:
|
||||
///
|
||||
/// - a [StaticCell](https://docs.rs/static_cell/latest/static_cell/) (safe)
|
||||
/// - a `static mut` (unsafe)
|
||||
/// - a local variable in a function you know never returns (like `fn main() -> !`), upgrading its lifetime with `transmute`. (unsafe)
|
||||
///
|
||||
/// This function never returns.
|
||||
pub fn run(&'static mut self, init: impl FnOnce(Spawner)) -> ! {
|
||||
init(self.inner.spawner());
|
||||
|
||||
loop {
|
||||
unsafe {
|
||||
self.inner.poll();
|
||||
self.context.wait();
|
||||
};
|
||||
}
|
||||
}
|
||||
}
|
Loading…
Reference in a new issue