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Use Relaxed atomics with fence instead of SeqCst

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This commit is contained in:
Dario Nieuwenhuis 2021-02-20 01:43:10 +01:00
parent 406f3b7cbf
commit 91aaea761e
1 changed files with 4 additions and 3 deletions
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7
embassy-nrf/src/rtc.rs
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@ -1,6 +1,6 @@
use core::cell::Cell;
use core::ops::Deref;
use core::sync::atomic::{AtomicU32, Ordering};
use core::sync::atomic::{compiler_fence, AtomicU32, Ordering};
use embassy::time::Clock;
@ -143,7 +143,7 @@ impl<T: Instance> RTC<T> {
fn next_period(&self) {
interrupt::free(|cs| {
let period = self.period.fetch_add(1, Ordering::SeqCst) + 1;
let period = self.period.fetch_add(1, Ordering::Relaxed) + 1;
let t = (period as u64) << 23;
for n in 0..ALARM_COUNT {
@ -231,7 +231,8 @@ impl<T: Instance> RTC<T> {
impl<T: Instance> embassy::time::Clock for RTC<T> {
fn now(&self) -> u64 {
// `period` MUST be read before `counter`, see comment at the top for details.
let period = self.period.load(Ordering::SeqCst);
let period = self.period.load(Ordering::Relaxed);
compiler_fence(Ordering::Acquire);
let counter = self.rtc.counter.read().bits();
calc_now(period, counter)
}