embassy_nrf/
wdt.rs

1//! Watchdog Timer (WDT) driver.
2//!
3//! This HAL implements a basic watchdog timer with 1..=8 handles.
4//! Once the watchdog has been started, it cannot be stopped.
5
6#![macro_use]
7
8use core::hint::unreachable_unchecked;
9
10use embassy_hal_internal::PeripheralType;
11
12use crate::pac::wdt::vals;
13pub use crate::pac::wdt::vals::{Halt as HaltConfig, Sleep as SleepConfig};
14use crate::{interrupt, pac, peripherals, Peri};
15
16const MIN_TICKS: u32 = 15;
17
18/// WDT configuration.
19#[non_exhaustive]
20pub struct Config {
21    /// Number of 32768 Hz ticks in each watchdog period.
22    ///
23    /// Note: there is a minimum of 15 ticks (458 microseconds). If a lower
24    /// number is provided, 15 ticks will be used as the configured value.
25    pub timeout_ticks: u32,
26
27    /// Should the watchdog continue to count during sleep modes?
28    pub action_during_sleep: SleepConfig,
29
30    /// Should the watchdog continue to count when the CPU is halted for debug?
31    pub action_during_debug_halt: HaltConfig,
32}
33
34impl Config {
35    /// Create a config structure from the current configuration of the WDT
36    /// peripheral.
37    pub fn try_new<T: Instance>(_wdt: &Peri<'_, T>) -> Option<Self> {
38        let r = T::REGS;
39
40        #[cfg(not(any(feature = "_nrf91", feature = "_nrf5340")))]
41        let runstatus = r.runstatus().read().runstatus();
42        #[cfg(any(feature = "_nrf91", feature = "_nrf5340"))]
43        let runstatus = r.runstatus().read().runstatuswdt();
44
45        if runstatus {
46            let config = r.config().read();
47            Some(Self {
48                timeout_ticks: r.crv().read(),
49                action_during_sleep: config.sleep(),
50                action_during_debug_halt: config.halt(),
51            })
52        } else {
53            None
54        }
55    }
56}
57
58impl Default for Config {
59    fn default() -> Self {
60        Self {
61            timeout_ticks: 32768, // 1 second
62            action_during_debug_halt: HaltConfig::RUN,
63            action_during_sleep: SleepConfig::RUN,
64        }
65    }
66}
67
68/// Watchdog driver.
69pub struct Watchdog<T: Instance> {
70    _wdt: Peri<'static, T>,
71}
72
73impl<T: Instance> Watchdog<T> {
74    /// Try to create a new watchdog driver.
75    ///
76    /// This function will return an error if the watchdog is already active
77    /// with a `config` different to the requested one, or a different number of
78    /// enabled handles.
79    ///
80    /// `N` must be between 1 and 8, inclusive.
81    #[inline]
82    pub fn try_new<const N: usize>(
83        wdt: Peri<'static, T>,
84        config: Config,
85    ) -> Result<(Self, [WatchdogHandle; N]), Peri<'static, T>> {
86        assert!(N >= 1 && N <= 8);
87
88        let r = T::REGS;
89
90        let crv = config.timeout_ticks.max(MIN_TICKS);
91        let rren = crate::pac::wdt::regs::Rren((1u32 << N) - 1);
92
93        #[cfg(not(any(feature = "_nrf91", feature = "_nrf5340")))]
94        let runstatus = r.runstatus().read().runstatus();
95        #[cfg(any(feature = "_nrf91", feature = "_nrf5340"))]
96        let runstatus = r.runstatus().read().runstatuswdt();
97
98        if runstatus {
99            let curr_config = r.config().read();
100            if curr_config.halt() != config.action_during_debug_halt
101                || curr_config.sleep() != config.action_during_sleep
102                || r.crv().read() != crv
103                || r.rren().read() != rren
104            {
105                return Err(wdt);
106            }
107        } else {
108            r.config().write(|w| {
109                w.set_sleep(config.action_during_sleep);
110                w.set_halt(config.action_during_debug_halt);
111            });
112            r.intenset().write(|w| w.set_timeout(true));
113
114            r.crv().write_value(crv);
115            r.rren().write_value(rren);
116            r.tasks_start().write_value(1);
117        }
118
119        let this = Self { _wdt: wdt };
120
121        let mut handles = [const { WatchdogHandle { index: 0 } }; N];
122        for i in 0..N {
123            handles[i] = unsafe { WatchdogHandle::steal::<T>(i as u8) };
124            handles[i].pet();
125        }
126
127        Ok((this, handles))
128    }
129
130    /// Enable the watchdog interrupt.
131    ///
132    /// NOTE: Although the interrupt will occur, there is no way to prevent
133    /// the reset from occurring. From the time the event was fired, the
134    /// system will reset two LFCLK ticks later (61 microseconds) if the
135    /// interrupt has been enabled.
136    #[inline(always)]
137    pub fn enable_interrupt(&mut self) {
138        T::REGS.intenset().write(|w| w.set_timeout(true));
139    }
140
141    /// Disable the watchdog interrupt.
142    ///
143    /// NOTE: This has no effect on the reset caused by the Watchdog.
144    #[inline(always)]
145    pub fn disable_interrupt(&mut self) {
146        T::REGS.intenclr().write(|w| w.set_timeout(true));
147    }
148
149    /// Is the watchdog still awaiting pets from any handle?
150    ///
151    /// This reports whether sufficient pets have been received from all
152    /// handles to prevent a reset this time period.
153    #[inline(always)]
154    pub fn awaiting_pets(&self) -> bool {
155        let r = T::REGS;
156        let enabled = r.rren().read().0;
157        let status = r.reqstatus().read().0;
158        (status & enabled) == 0
159    }
160}
161
162/// Watchdog handle.
163pub struct WatchdogHandle {
164    index: u8,
165}
166
167impl WatchdogHandle {
168    fn regs(&self) -> pac::wdt::Wdt {
169        match self.index / 8 {
170            #[cfg(not(feature = "_multi_wdt"))]
171            peripherals::WDT::INDEX => peripherals::WDT::REGS,
172            #[cfg(feature = "_multi_wdt")]
173            peripherals::WDT0::INDEX => peripherals::WDT0::REGS,
174            #[cfg(feature = "_multi_wdt")]
175            peripherals::WDT1::INDEX => peripherals::WDT1::REGS,
176            _ => unsafe { unreachable_unchecked() },
177        }
178    }
179
180    fn rr_index(&self) -> usize {
181        usize::from(self.index % 8)
182    }
183
184    /// Pet the watchdog.
185    ///
186    /// This function pets the given watchdog handle.
187    ///
188    /// NOTE: All active handles must be pet within the time interval to
189    /// prevent a reset from occurring.
190    #[inline]
191    pub fn pet(&mut self) {
192        let r = self.regs();
193        r.rr(self.rr_index()).write(|w| w.set_rr(vals::Rr::RELOAD));
194    }
195
196    /// Has this handle been pet within the current window?
197    pub fn is_pet(&self) -> bool {
198        let r = self.regs();
199        !r.reqstatus().read().rr(self.rr_index())
200    }
201
202    /// Steal a watchdog handle by index.
203    ///
204    /// # Safety
205    /// Watchdog must be initialized and `index` must be between `0` and `N-1`
206    /// where `N` is the handle count when initializing.
207    pub unsafe fn steal<T: Instance>(index: u8) -> Self {
208        Self {
209            index: T::INDEX * 8 + index,
210        }
211    }
212}
213
214pub(crate) trait SealedInstance {
215    const REGS: pac::wdt::Wdt;
216    const INDEX: u8;
217}
218
219/// WDT instance.
220#[allow(private_bounds)]
221pub trait Instance: SealedInstance + PeripheralType + 'static + Send {
222    /// Interrupt for this peripheral.
223    type Interrupt: interrupt::typelevel::Interrupt;
224}
225
226macro_rules! impl_wdt {
227    ($type:ident, $pac_type:ident, $irq:ident, $index:literal) => {
228        impl crate::wdt::SealedInstance for peripherals::$type {
229            const REGS: pac::wdt::Wdt = pac::$pac_type;
230            const INDEX: u8 = $index;
231        }
232        impl crate::wdt::Instance for peripherals::$type {
233            type Interrupt = crate::interrupt::typelevel::$irq;
234        }
235    };
236}
embassy_nrf/wdt.rs

embassy_nrf/
wdt.rs
