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|
use crate::{
hw::mcu,
mutex::{AnyCtx, LazyMainInit, MainCtx, MutexCell},
};
#[allow(non_snake_case)]
pub struct TimerPeriph {
pub TC0: mcu::TC0,
}
// SAFETY: This variable is initialized when constructing the MainCtx.
pub static TIMER_PERIPH: LazyMainInit<TimerPeriph> = unsafe { LazyMainInit::uninit() };
static TIMER_UPPER: MutexCell<u8> = MutexCell::new(0);
pub const TIMER_TICK_US: u8 = 16; // 16 us per tick.
pub fn timer_init(m: &MainCtx) {
// Timer 0 configuration:
// CS: 256 -> 16 us per timer tick.
TIMER_PERIPH
.deref(m)
.TC0
.tccr0
.write(|w| w.cs0().running_clk_256());
}
// SAFETY: This function may only do atomic-read-only accesses, because it's
// called from all contexts, including interrupt context.
#[inline(always)]
pub fn timer_get(a: &AnyCtx) -> Timestamp {
// SAFETY: This function only does atomic peripheral read-only accesses.
// Therefore, it is safe to pretend to be the main context, even
// if we were actually called from irq context.
let m = unsafe { a.to_main_ctx() };
TIMER_PERIPH.deref(&m).TC0.tcnt0.read().bits().into()
}
#[inline(never)]
pub fn timer_get_large(m: &MainCtx) -> LargeTimestamp {
let mut upper = TIMER_UPPER.get(m);
let mut lower = TIMER_PERIPH.deref(m).TC0.tcnt0.read().bits();
// Increment the upper part, if the lower part had an overflow.
if TIMER_PERIPH.deref(m).TC0.tifr.read().tov0().bit() {
TIMER_PERIPH.deref(m).TC0.tifr.write(|w| w.tov0().set_bit());
lower = TIMER_PERIPH.deref(m).TC0.tcnt0.read().bits();
upper = upper.wrapping_add(1);
TIMER_UPPER.set(m, upper);
}
((upper as u16) << 8 | lower as u16).into()
}
macro_rules! impl_timestamp {
($rel:ident, $abs:ident, $reltype:ty, $abstype:ty) => {
#[derive(PartialEq, Eq, Copy, Clone)]
pub struct $abs(pub $abstype);
impl $abs {
#[inline]
pub const fn new() -> Self {
$abs(0)
}
#[inline]
pub const fn from_ticks(ticks: $abstype) -> Self {
$abs(ticks)
}
#[inline]
pub const fn from_micros(us: u32) -> $abs {
$abs((us / TIMER_TICK_US as u32) as $abstype)
}
#[inline]
pub const fn from_millis(ms: u32) -> $abs {
$abs(((ms * 1000) / TIMER_TICK_US as u32) as $abstype)
}
}
impl Default for $abs {
#[inline]
fn default() -> Self {
Self::new()
}
}
impl Ord for $abs {
#[inline]
fn cmp(&self, other: &Self) -> core::cmp::Ordering {
if self.0 == other.0 {
core::cmp::Ordering::Equal
} else if self.0.wrapping_sub(other.0) & (1 << (<$abstype>::BITS - 1)) == 0 {
core::cmp::Ordering::Greater
} else {
core::cmp::Ordering::Less
}
}
}
impl PartialOrd for $abs {
#[inline]
fn partial_cmp(&self, other: &Self) -> Option<core::cmp::Ordering> {
Some(self.cmp(other))
}
}
impl core::ops::Add<$rel> for $abs {
type Output = Self;
#[inline]
fn add(self, other: $rel) -> Self::Output {
self.0.wrapping_add(other.0 as $abstype).into()
}
}
impl core::ops::Sub for $abs {
type Output = $rel;
#[inline]
fn sub(self, other: Self) -> Self::Output {
(self.0.wrapping_sub(other.0) as $reltype).into()
}
}
impl From<$abstype> for $abs {
#[inline]
fn from(stamp: $abstype) -> Self {
$abs(stamp)
}
}
impl From<$abs> for $abstype {
#[inline]
fn from(stamp: $abs) -> Self {
stamp.0
}
}
};
}
macro_rules! impl_reltimestamp {
($rel:ident, $abs:ident, $reltype:ty, $abstype:ty) => {
#[derive(PartialEq, Eq, Copy, Clone, PartialOrd, Ord)]
pub struct $rel(pub $reltype);
impl $rel {
#[inline]
pub const fn new() -> Self {
$rel(0)
}
#[inline]
pub const fn from_ticks(ticks: $reltype) -> Self {
$rel(ticks)
}
#[inline]
pub const fn from_micros(us: i32) -> $rel {
$rel((us / TIMER_TICK_US as i32) as $reltype)
}
#[inline]
pub const fn from_millis(ms: i32) -> $rel {
$rel(((ms * 1000) / TIMER_TICK_US as i32) as $reltype)
}
}
impl Default for $rel {
#[inline]
fn default() -> Self {
Self::new()
}
}
impl core::ops::Add<$rel> for $rel {
type Output = Self;
#[inline]
fn add(self, other: $rel) -> Self::Output {
self.0.wrapping_add(other.0).into()
}
}
impl core::ops::Sub for $rel {
type Output = $rel;
#[inline]
fn sub(self, other: Self) -> Self::Output {
self.0.wrapping_sub(other.0).into()
}
}
impl From<$reltype> for $rel {
#[inline]
fn from(relstamp: $reltype) -> Self {
$rel(relstamp)
}
}
impl From<$rel> for $reltype {
#[inline]
fn from(relstamp: $rel) -> Self {
relstamp.0
}
}
};
}
impl_timestamp!(RelTimestamp, Timestamp, i8, u8);
impl_timestamp!(RelLargeTimestamp, LargeTimestamp, i16, u16);
impl_reltimestamp!(RelTimestamp, Timestamp, i8, u8);
impl_reltimestamp!(RelLargeTimestamp, LargeTimestamp, i16, u16);
impl From<LargeTimestamp> for Timestamp {
#[inline]
fn from(stamp: LargeTimestamp) -> Timestamp {
(stamp.0 as u8).into()
}
}
// vim: ts=4 sw=4 expandtab
|
