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stm32/low-power: create one critical-section for all time ops

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This commit is contained in:
xoviat
2023-09-21 19:32:48 -05:00
parent 02b0523199
commit 7cf327130e
3 changed files with 99 additions and 80 deletions
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100
embassy-stm32/src/time_driver.rs
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@ -266,32 +266,28 @@ impl RtcDriver {
f(alarm.ctx.get());
}
#[cfg(feature = "low-power")]
/// Set the rtc but panic if it's already been set
pub(crate) fn set_rtc(&self, rtc: &'static Rtc) {
critical_section::with(|cs| assert!(self.rtc.borrow(cs).replace(Some(rtc)).is_none()));
}
/*
Low-power private functions: all operate within a critical seciton
*/
#[cfg(feature = "low-power")]
/// Compute the approximate amount of time until the next alarm
fn time_until_next_alarm(&self) -> embassy_time::Duration {
critical_section::with(|cs| {
let now = self.now() + 32;
fn time_until_next_alarm(&self, cs: CriticalSection) -> embassy_time::Duration {
let now = self.now() + 32;
embassy_time::Duration::from_ticks(
self.alarms
.borrow(cs)
.iter()
.map(|alarm: &AlarmState| alarm.timestamp.get().saturating_sub(now))
.min()
.unwrap_or(u64::MAX),
)
})
embassy_time::Duration::from_ticks(
self.alarms
.borrow(cs)
.iter()
.map(|alarm: &AlarmState| alarm.timestamp.get().saturating_sub(now))
.min()
.unwrap_or(u64::MAX),
)
}
#[cfg(feature = "low-power")]
/// Add the given offset to the current time
fn add_time(&self, offset: embassy_time::Duration) {
fn add_time(&self, offset: embassy_time::Duration, cs: CriticalSection) {
let offset = offset.as_ticks();
let cnt = T::regs_gp16().cnt().read().cnt() as u32;
let period = self.period.load(Ordering::SeqCst);
@ -322,51 +318,57 @@ impl RtcDriver {
T::regs_gp16().cnt().write(|w| w.set_cnt(cnt as u16));
// Now, recompute all alarms
critical_section::with(|cs| {
for i in 0..ALARM_COUNT {
let alarm_handle = unsafe { AlarmHandle::new(i as u8) };
let alarm = self.get_alarm(cs, alarm_handle);
for i in 0..ALARM_COUNT {
let alarm_handle = unsafe { AlarmHandle::new(i as u8) };
let alarm = self.get_alarm(cs, alarm_handle);
self.set_alarm(alarm_handle, alarm.timestamp.get());
}
})
self.set_alarm(alarm_handle, alarm.timestamp.get());
}
}
#[cfg(feature = "low-power")]
/// Stop the wakeup alarm, if enabled, and add the appropriate offset
fn stop_wakeup_alarm(&self) {
critical_section::with(|cs| {
if let Some(offset) = self.rtc.borrow(cs).get().unwrap().stop_wakeup_alarm() {
self.add_time(offset);
}
});
fn stop_wakeup_alarm(&self, cs: CriticalSection) {
if let Some(offset) = self.rtc.borrow(cs).get().unwrap().stop_wakeup_alarm(cs) {
self.add_time(offset, cs);
}
}
/*
Low-power public functions: all create a critical section
*/
#[cfg(feature = "low-power")]
/// Set the rtc but panic if it's already been set
pub(crate) fn set_rtc(&self, rtc: &'static Rtc) {
critical_section::with(|cs| assert!(self.rtc.borrow(cs).replace(Some(rtc)).is_none()));
}
#[cfg(feature = "low-power")]
/// Pause the timer if ready; return err if not
pub(crate) fn pause_time(&self) -> Result<(), ()> {
/*
If the wakeup timer is currently running, then we need to stop it and
add the elapsed time to the current time
*/
self.stop_wakeup_alarm();
critical_section::with(|cs| {
/*
If the wakeup timer is currently running, then we need to stop it and
add the elapsed time to the current time, as this will impact the result
of `time_until_next_alarm`.
*/
self.stop_wakeup_alarm(cs);
let time_until_next_alarm = self.time_until_next_alarm();
if time_until_next_alarm < embassy_time::Duration::from_millis(250) {
Err(())
} else {
critical_section::with(|cs| {
let time_until_next_alarm = self.time_until_next_alarm(cs);
if time_until_next_alarm < embassy_time::Duration::from_millis(250) {
Err(())
} else {
self.rtc
.borrow(cs)
.get()
.unwrap()
.start_wakeup_alarm(time_until_next_alarm);
});
.start_wakeup_alarm(time_until_next_alarm, cs);
T::regs_gp16().cr1().modify(|w| w.set_cen(false));
T::regs_gp16().cr1().modify(|w| w.set_cen(false));
Ok(())
}
Ok(())
}
})
}
#[cfg(feature = "low-power")]
@ -378,9 +380,11 @@ impl RtcDriver {
return;
}
self.stop_wakeup_alarm();
critical_section::with(|cs| {
self.stop_wakeup_alarm(cs);
T::regs_gp16().cr1().modify(|w| w.set_cen(true));
T::regs_gp16().cr1().modify(|w| w.set_cen(true));
})
}
}