diff --git a/embassy-stm32/Cargo.toml b/embassy-stm32/Cargo.toml index 828414f2e..048d231d5 100644 --- a/embassy-stm32/Cargo.toml +++ b/embassy-stm32/Cargo.toml @@ -38,6 +38,7 @@ embassy-hal-internal = {version = "0.1.0", path = "../embassy-hal-internal", fea embassy-embedded-hal = {version = "0.1.0", path = "../embassy-embedded-hal" } embassy-net-driver = { version = "0.1.0", path = "../embassy-net-driver" } embassy-usb-driver = {version = "0.1.0", path = "../embassy-usb-driver", optional = true } +embassy-executor = { version = "0.2.0", path = "../embassy-executor", optional = true } embedded-hal-02 = { package = "embedded-hal", version = "0.2.6", features = ["unproven"] } embedded-hal-1 = { package = "embedded-hal", version = "=1.0.0-rc.1", optional = true} @@ -88,7 +89,8 @@ rt = ["stm32-metapac/rt"] defmt = ["dep:defmt", "bxcan/unstable-defmt", "embassy-sync/defmt", "embassy-embedded-hal/defmt", "embassy-hal-internal/defmt", "embedded-io-async?/defmt-03", "embassy-usb-driver?/defmt", "embassy-net-driver/defmt", "embassy-time?/defmt"] exti = [] -low-power = [] +low-power = [ "dep:embassy-executor", "embassy-executor/arch-cortex-m" ] +embassy-executor = [] ## Automatically generate `memory.x` file using [`stm32-metapac`](https://docs.rs/stm32-metapac/) memory-x = ["stm32-metapac/memory-x"] diff --git a/embassy-stm32/src/low_power.rs b/embassy-stm32/src/low_power.rs index ddcfbbb1e..3fe28b9df 100644 --- a/embassy-stm32/src/low_power.rs +++ b/embassy-stm32/src/low_power.rs @@ -1,3 +1,10 @@ +use core::arch::asm; +use core::marker::PhantomData; + +use embassy_executor::*; + +const THREAD_PENDER: usize = usize::MAX; + use crate::rtc::{Rtc, RtcInstant}; static mut RTC: Option<&'static Rtc> = None; @@ -13,3 +20,62 @@ pub fn start_wakeup_alarm(requested_duration: embassy_time::Duration) -> RtcInst pub fn stop_wakeup_alarm() -> RtcInstant { unsafe { RTC }.unwrap().stop_wakeup_alarm() } + +/// 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 Executor { + inner: raw::Executor, + not_send: PhantomData<*mut ()>, +} + +impl Executor { + /// Create a new Executor. + pub fn new() -> Self { + Self { + inner: raw::Executor::new(THREAD_PENDER as *mut ()), + not_send: PhantomData, + } + } + + fn configure_power(&self) { + todo!() + } + + /// 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.configure_power(); + asm!("wfe"); + }; + } + } +} diff --git a/embassy-stm32/src/rtc/v2.rs b/embassy-stm32/src/rtc/v2.rs index 744e9a114..f6565a721 100644 --- a/embassy-stm32/src/rtc/v2.rs +++ b/embassy-stm32/src/rtc/v2.rs @@ -162,7 +162,7 @@ impl super::Rtc { /// /// note: this api is exposed for testing purposes until low power is implemented. /// it is not intended to be public - pub(crate) fn start_wakeup_alarm(requested_duration: embassy_time::Duration) -> RtcInstant { + pub(crate) fn start_wakeup_alarm(&self, requested_duration: embassy_time::Duration) -> RtcInstant { use embassy_time::{Duration, TICK_HZ}; use crate::interrupt::typelevel::Interrupt; @@ -217,7 +217,7 @@ impl super::Rtc { /// /// note: this api is exposed for testing purposes until low power is implemented. /// it is not intended to be public - pub(crate) fn stop_wakeup_alarm() -> RtcInstant { + pub(crate) fn stop_wakeup_alarm(&self) -> RtcInstant { use crate::interrupt::typelevel::Interrupt; crate::interrupt::typelevel::RTC_WKUP::disable();