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time: allow storing state inside the driver struct.

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This commit is contained in:
Dario Nieuwenhuis
2021-08-25 18:50:05 +02:00
parent 55b2d7b524
commit 7c0990ad1e
5 changed files with 218 additions and 197 deletions
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132
embassy-rp/src/timer.rs
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@ -19,38 +19,40 @@ const DUMMY_ALARM: AlarmState = AlarmState {
callback: Cell::new(None),
};
static ALARMS: Mutex<[AlarmState; ALARM_COUNT]> = Mutex::new([DUMMY_ALARM; ALARM_COUNT]);
static NEXT_ALARM: AtomicU8 = AtomicU8::new(0);
struct TimerDriver {
alarms: Mutex<[AlarmState; ALARM_COUNT]>,
next_alarm: AtomicU8,
}
fn now() -> u64 {
loop {
unsafe {
let hi = pac::TIMER.timerawh().read();
let lo = pac::TIMER.timerawl().read();
let hi2 = pac::TIMER.timerawh().read();
if hi == hi2 {
return (hi as u64) << 32 | (lo as u64);
embassy::time_driver_impl!(static DRIVER: TimerDriver = TimerDriver{
alarms: Mutex::new([DUMMY_ALARM; ALARM_COUNT]),
next_alarm: AtomicU8::new(0),
});
impl Driver for TimerDriver {
fn now(&self) -> u64 {
loop {
unsafe {
let hi = pac::TIMER.timerawh().read();
let lo = pac::TIMER.timerawl().read();
let hi2 = pac::TIMER.timerawh().read();
if hi == hi2 {
return (hi as u64) << 32 | (lo as u64);
}
}
}
}
}
struct TimerDriver;
embassy::time_driver_impl!(TimerDriver);
impl Driver for TimerDriver {
fn now() -> u64 {
now()
}
unsafe fn allocate_alarm() -> Option<AlarmHandle> {
let id = NEXT_ALARM.fetch_update(Ordering::AcqRel, Ordering::Acquire, |x| {
if x < ALARM_COUNT as u8 {
Some(x + 1)
} else {
None
}
});
unsafe fn allocate_alarm(&self) -> Option<AlarmHandle> {
let id = self
.next_alarm
.fetch_update(Ordering::AcqRel, Ordering::Acquire, |x| {
if x < ALARM_COUNT as u8 {
Some(x + 1)
} else {
None
}
});
match id {
Ok(id) => Some(AlarmHandle::new(id)),
@ -58,18 +60,18 @@ impl Driver for TimerDriver {
}
}
fn set_alarm_callback(alarm: AlarmHandle, callback: fn(*mut ()), ctx: *mut ()) {
fn set_alarm_callback(&self, alarm: AlarmHandle, callback: fn(*mut ()), ctx: *mut ()) {
let n = alarm.id() as usize;
critical_section::with(|cs| {
let alarm = &ALARMS.borrow(cs)[n];
let alarm = &self.alarms.borrow(cs)[n];
alarm.callback.set(Some((callback, ctx)));
})
}
fn set_alarm(alarm: AlarmHandle, timestamp: u64) {
fn set_alarm(&self, alarm: AlarmHandle, timestamp: u64) {
let n = alarm.id() as usize;
critical_section::with(|cs| {
let alarm = &ALARMS.borrow(cs)[n];
let alarm = &self.alarms.borrow(cs)[n];
alarm.timestamp.set(timestamp);
// Arm it.
@ -78,44 +80,46 @@ impl Driver for TimerDriver {
// it is checked if the alarm time has passed.
unsafe { pac::TIMER.alarm(n).write_value(timestamp as u32) };
let now = now();
let now = self.now();
// If alarm timestamp has passed, trigger it instantly.
// This disarms it.
if timestamp <= now {
trigger_alarm(n, cs);
self.trigger_alarm(n, cs);
}
})
}
}
fn check_alarm(n: usize) {
critical_section::with(|cs| {
let alarm = &ALARMS.borrow(cs)[n];
let timestamp = alarm.timestamp.get();
if timestamp <= now() {
trigger_alarm(n, cs)
} else {
// Not elapsed, arm it again.
// This can happen if it was set more than 2^32 us in the future.
unsafe { pac::TIMER.alarm(n).write_value(timestamp as u32) };
impl TimerDriver {
fn check_alarm(&self, n: usize) {
critical_section::with(|cs| {
let alarm = &self.alarms.borrow(cs)[n];
let timestamp = alarm.timestamp.get();
if timestamp <= self.now() {
self.trigger_alarm(n, cs)
} else {
// Not elapsed, arm it again.
// This can happen if it was set more than 2^32 us in the future.
unsafe { pac::TIMER.alarm(n).write_value(timestamp as u32) };
}
});
// clear the irq
unsafe { pac::TIMER.intr().write(|w| w.set_alarm(n, true)) }
}
fn trigger_alarm(&self, n: usize, cs: CriticalSection) {
// disarm
unsafe { pac::TIMER.armed().write(|w| w.set_armed(1 << n)) }
let alarm = &self.alarms.borrow(cs)[n];
alarm.timestamp.set(u64::MAX);
// Call after clearing alarm, so the callback can set another alarm.
if let Some((f, ctx)) = alarm.callback.get() {
f(ctx);
}
});
// clear the irq
unsafe { pac::TIMER.intr().write(|w| w.set_alarm(n, true)) }
}
fn trigger_alarm(n: usize, cs: CriticalSection) {
// disarm
unsafe { pac::TIMER.armed().write(|w| w.set_armed(1 << n)) }
let alarm = &ALARMS.borrow(cs)[n];
alarm.timestamp.set(u64::MAX);
// Call after clearing alarm, so the callback can set another alarm.
if let Some((f, ctx)) = alarm.callback.get() {
f(ctx);
}
}
@ -123,7 +127,7 @@ fn trigger_alarm(n: usize, cs: CriticalSection) {
pub unsafe fn init() {
// init alarms
critical_section::with(|cs| {
let alarms = ALARMS.borrow(cs);
let alarms = DRIVER.alarms.borrow(cs);
for a in alarms {
a.timestamp.set(u64::MAX);
}
@ -144,20 +148,20 @@ pub unsafe fn init() {
#[interrupt]
unsafe fn TIMER_IRQ_0() {
check_alarm(0)
DRIVER.check_alarm(0)
}
#[interrupt]
unsafe fn TIMER_IRQ_1() {
check_alarm(1)
DRIVER.check_alarm(1)
}
#[interrupt]
unsafe fn TIMER_IRQ_2() {
check_alarm(2)
DRIVER.check_alarm(2)
}
#[interrupt]
unsafe fn TIMER_IRQ_3() {
check_alarm(3)
DRIVER.check_alarm(3)
}