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Add support for multi alarm to RTC.

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This commit is contained in:
Dario Nieuwenhuis 2020-09-25 23:25:49 +02:00
parent a734a9ff46
commit cf1d604749
4 changed files with 75 additions and 30 deletions
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93
embassy-nrf/src/rtc.rs
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@ -3,7 +3,7 @@ use core::ops::Deref;
use core::sync::atomic::{AtomicU32, Ordering};
use crate::interrupt;
use crate::interrupt::Mutex;
use crate::interrupt::{CriticalSection, Mutex};
use crate::pac::{rtc0, Interrupt, RTC0, RTC1};
#[cfg(any(feature = "52832", feature = "52833", feature = "52840"))]
@ -34,6 +34,22 @@ mod test {
}
}
struct AlarmState {
timestamp: Cell<u64>,
callback: Cell<Option<fn()>>,
}
impl AlarmState {
fn new() -> Self {
Self {
timestamp: Cell::new(u64::MAX),
callback: Cell::new(None),
}
}
}
const ALARM_COUNT: usize = 3;
pub struct RTC<T> {
rtc: T,
@ -50,7 +66,7 @@ pub struct RTC<T> {
period: AtomicU32,
/// Timestamp at which to fire alarm. u64::MAX if no alarm is scheduled.
alarm: Mutex<Cell<(u64, Option<fn()>)>>,
alarms: Mutex<[AlarmState; ALARM_COUNT]>,
}
unsafe impl<T> Send for RTC<T> {}
@ -61,7 +77,7 @@ impl<T: Instance> RTC<T> {
Self {
rtc,
period: AtomicU32::new(0),
alarm: Mutex::new(Cell::new((u64::MAX, None))),
alarms: Mutex::new([AlarmState::new(), AlarmState::new(), AlarmState::new()]),
}
}
@ -101,9 +117,13 @@ impl<T: Instance> RTC<T> {
self.next_period();
}
if self.rtc.events_compare[1].read().bits() == 1 {
self.rtc.events_compare[1].write(|w| w);
self.trigger_alarm();
for n in 0..ALARM_COUNT {
if self.rtc.events_compare[n + 1].read().bits() == 1 {
self.rtc.events_compare[n + 1].write(|w| w);
interrupt::free(|cs| {
self.trigger_alarm(n, cs);
})
}
}
}
@ -112,35 +132,43 @@ impl<T: Instance> RTC<T> {
let period = self.period.fetch_add(1, Ordering::Relaxed) + 1;
let t = (period as u64) << 23;
let (at, _) = self.alarm.borrow(cs).get();
for alarm in self.alarms.borrow(cs) {
let at = alarm.timestamp.get();
let diff = at - t;
if diff < 0xc00000 {
self.rtc.cc[1].write(|w| unsafe { w.bits(at as u32 & 0xFFFFFF) });
self.rtc.intenset.write(|w| w.compare1().set());
let diff = at - t;
if diff < 0xc00000 {
self.rtc.cc[1].write(|w| unsafe { w.bits(at as u32 & 0xFFFFFF) });
self.rtc.intenset.write(|w| w.compare1().set());
}
}
})
}
fn trigger_alarm(&self) {
fn trigger_alarm(&self, n: usize, cs: &CriticalSection) {
self.rtc.intenclr.write(|w| w.compare1().clear());
interrupt::free(|cs| {
let alarm = self.alarm.borrow(cs);
let (_, f) = alarm.get();
alarm.set((u64::MAX, None));
// Call after clearing alarm, so the callback can set another alarm.
f.map(|f| f())
});
let alarm = &self.alarms.borrow(cs)[n];
alarm.timestamp.set(u64::MAX);
// Call after clearing alarm, so the callback can set another alarm.
alarm.callback.get().map(|f| f());
}
fn do_set_alarm(&self, timestamp: u64, callback: Option<fn()>) {
fn set_alarm_callback(&self, n: usize, callback: fn()) {
interrupt::free(|cs| {
self.alarm.borrow(cs).set((timestamp, callback));
let alarm = &self.alarms.borrow(cs)[n];
alarm.callback.set(Some(callback));
})
}
fn set_alarm(&self, n: usize, timestamp: u64) {
interrupt::free(|cs| {
let alarm = &self.alarms.borrow(cs)[n];
alarm.timestamp.set(timestamp);
let t = self.now();
if timestamp <= t {
self.trigger_alarm();
self.trigger_alarm(n, cs);
return;
}
@ -155,7 +183,7 @@ impl<T: Instance> RTC<T> {
let t = self.now();
if timestamp <= t {
self.trigger_alarm();
self.trigger_alarm(n, cs);
return;
}
} else {
@ -165,21 +193,32 @@ impl<T: Instance> RTC<T> {
}
pub fn alarm0(&'static self) -> Alarm<T> {
Alarm { rtc: self }
Alarm { n: 0, rtc: self }
}
pub fn alarm1(&'static self) -> Alarm<T> {
Alarm { n: 1, rtc: self }
}
pub fn alarm2(&'static self) -> Alarm<T> {
Alarm { n: 2, rtc: self }
}
}
pub struct Alarm<T: Instance> {
n: usize,
rtc: &'static RTC<T>,
}
impl<T: Instance> embassy::time::Alarm for Alarm<T> {
fn set(&self, timestamp: u64, callback: fn()) {
self.rtc.do_set_alarm(timestamp, Some(callback));
fn set_callback(&self, callback: fn()) {
self.rtc.set_alarm_callback(self.n, callback);
}
fn set(&self, timestamp: u64) {
self.rtc.set_alarm(self.n, timestamp);
}
fn clear(&self) {
self.rtc.do_set_alarm(u64::MAX, None);
self.rtc.set_alarm(self.n, u64::MAX);
}
}

3
embassy/src/executor.rs
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@ -27,6 +27,7 @@ pub struct Executor<M, A: Alarm> {
impl<M: Model, A: Alarm> Executor<M, A> {
pub fn new(alarm: A) -> Self {
alarm.set_callback(M::signal);
Self {
inner: se::Executor::new(M::signal),
alarm,
@ -53,7 +54,7 @@ impl<M: Model, A: Alarm> Executor<M, A> {
match self.timer.next_expiration() {
// If this is in the past, set_alarm will immediately trigger the alarm,
// which will make the wfe immediately return so we do another loop iteration.
Some(at) => self.alarm.set(at, M::signal),
Some(at) => self.alarm.set(at),
None => self.alarm.clear(),
}
})

6
embassy/src/time.rs
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@ -273,13 +273,17 @@ impl Future for Timer {
/// Trait to register a callback at a given timestamp.
pub trait Alarm {
/// Sets the callback function to be called when the alarm triggers.
/// The callback may be called from any context (interrupt or thread mode).
fn set_callback(&self, callback: fn());
/// Sets an alarm at the given timestamp. When the clock reaches that
/// timestamp, the provided callback funcion will be called.
///
/// When callback is called, it is guaranteed that now() will return a value greater or equal than timestamp.
///
/// Only one alarm can be active at a time. This overwrites any previously-set alarm if any.
fn set(&self, timestamp: u64, callback: fn());
fn set(&self, timestamp: u64);
/// Clears the previously-set alarm.
/// If no alarm was set, this is a noop.

3
examples/src/bin/rtc_raw.rs
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@ -35,7 +35,8 @@ fn main() -> ! {
rtc.start();
alarm.set(53719, || info!("ALARM TRIGGERED"));
alarm.set_callback(|| info!("ALARM TRIGGERED"));
alarm.set(53719);
info!("initialized!");