//! [`Monotonic`](rtic_time::Monotonic) implementations for i.MX RT's GPT peripherals. //! //! # Example //! //! ``` //! use rtic_monotonics::imxrt::prelude::*; //! imxrt_gpt1_monotonic!(Mono, 1_000_000); //! //! fn init() { //! // Obtain ownership of the timer register block. //! let gpt1 = unsafe { imxrt_ral::gpt::GPT1::instance() }; //! //! // Configure the timer tick rate as specified earlier //! todo!("Configure the gpt1 peripheral to a tick rate of 1_000_000"); //! //! // Start the monotonic //! Mono::start(gpt1); //! } //! //! async fn usage() { //! loop { //! // Use the monotonic //! let timestamp = Mono::now(); //! Mono::delay(100.millis()).await; //! } //! } //! ``` use atomic_polyfill::{AtomicU32, Ordering}; use rtic_time::{ half_period_counter::calculate_now, timer_queue::{TimerQueue, TimerQueueBackend}, }; pub use imxrt_ral as ral; /// Common definitions and traits for using the i.MX RT monotonics pub mod prelude { #[cfg(feature = "imxrt_gpt1")] pub use crate::imxrt_gpt1_monotonic; #[cfg(feature = "imxrt_gpt2")] pub use crate::imxrt_gpt2_monotonic; pub use crate::Monotonic; pub use fugit::{self, ExtU64, ExtU64Ceil}; } #[doc(hidden)] #[macro_export] macro_rules! __internal_create_imxrt_timer_interrupt { ($mono_backend:ident, $timer:ident) => { #[no_mangle] #[allow(non_snake_case)] unsafe extern "C" fn $timer() { use $crate::TimerQueueBackend; $crate::imxrt::$mono_backend::timer_queue().on_monotonic_interrupt(); } }; } #[doc(hidden)] #[macro_export] macro_rules! __internal_create_imxrt_timer_struct { ($name:ident, $mono_backend:ident, $timer:ident, $tick_rate_hz:expr) => { /// A `Monotonic` based on the GPT peripheral. struct $name; impl $name { /// Starts the `Monotonic`. /// /// This method must be called only once. pub fn start(gpt: $crate::imxrt::ral::gpt::$timer) { $crate::__internal_create_imxrt_timer_interrupt!($mono_backend, $timer); $crate::imxrt::$mono_backend::_start(gpt); } } impl $crate::TimerQueueBasedMonotonic for $name { type Backend = $crate::imxrt::$mono_backend; type Instant = $crate::fugit::Instant< ::Ticks, 1, { $tick_rate_hz }, >; type Duration = $crate::fugit::Duration< ::Ticks, 1, { $tick_rate_hz }, >; } $crate::rtic_time::impl_embedded_hal_delay_fugit!($name); $crate::rtic_time::impl_embedded_hal_async_delay_fugit!($name); }; } /// Create a GPT1 based monotonic and register the GPT1 interrupt for it. /// /// See [`crate::imxrt`] for more details. /// /// # Arguments /// /// * `name` - The name that the monotonic type will have. /// * `tick_rate_hz` - The tick rate of the timer peripheral. It's the user's responsibility /// to configure the peripheral to the given frequency before starting the /// monotonic. #[cfg(feature = "imxrt_gpt1")] #[macro_export] macro_rules! imxrt_gpt1_monotonic { ($name:ident, $tick_rate_hz:expr) => { $crate::__internal_create_imxrt_timer_struct!($name, Gpt1Backend, GPT1, $tick_rate_hz); }; } /// Create a GPT2 based monotonic and register the GPT2 interrupt for it. /// /// See [`crate::imxrt`] for more details. /// /// # Arguments /// /// * `name` - The name that the monotonic type will have. /// * `tick_rate_hz` - The tick rate of the timer peripheral. It's the user's responsibility /// to configure the peripheral to the given frequency before starting the /// monotonic. #[cfg(feature = "imxrt_gpt2")] #[macro_export] macro_rules! imxrt_gpt2_monotonic { ($name:ident, $tick_rate_hz:expr) => { $crate::__internal_create_imxrt_timer_struct!($name, Gpt2Backend, GPT2, $tick_rate_hz); }; } macro_rules! make_timer { ($mono_name:ident, $backend_name:ident, $timer:ident, $period:ident, $tq:ident$(, doc: ($($doc:tt)*))?) => { /// GPT based [`TimerQueueBackend`]. $( #[cfg_attr(docsrs, doc(cfg($($doc)*)))] )? pub struct $backend_name; use ral::gpt::$timer; /// Number of 2^31 periods elapsed since boot. static $period: AtomicU32 = AtomicU32::new(0); static $tq: TimerQueue<$backend_name> = TimerQueue::new(); impl $backend_name { /// Starts the timer. /// /// **Do not use this function directly.** /// /// Use the prelude macros instead. pub fn _start(gpt: $timer) { // Disable the timer. ral::modify_reg!(ral::gpt, gpt, CR, EN: 0); // Clear all status registers. ral::write_reg!(ral::gpt, gpt, SR, 0b11_1111); // Base configuration ral::modify_reg!(ral::gpt, gpt, CR, ENMOD: 1, // Clear timer state FRR: 1, // Free-Run mode ); // Reset period $period.store(0, Ordering::SeqCst); // Enable interrupts ral::write_reg!(ral::gpt, gpt, IR, ROVIE: 1, // Rollover interrupt OF1IE: 1, // Timer compare 1 interrupt (for half-periods) OF2IE: 1, // Timer compare 2 interrupt (for dynamic wakeup) ); // Configure half-period interrupt ral::write_reg!(ral::gpt, gpt, OCR[0], 0x8000_0000); // Dynamic interrupt register; for now initialize to zero // so it gets combined with rollover interrupt ral::write_reg!(ral::gpt, gpt, OCR[1], 0x0000_0000); // Initialize timer queue $tq.initialize(Self {}); // Enable the timer ral::modify_reg!(ral::gpt, gpt, CR, EN: 1); ral::modify_reg!(ral::gpt, gpt, CR, ENMOD: 0, // Keep state when disabled ); // SAFETY: We take full ownership of the peripheral and interrupt vector, // plus we are not using any external shared resources so we won't impact // basepri/source masking based critical sections. unsafe { crate::set_monotonic_prio(ral::NVIC_PRIO_BITS, ral::Interrupt::$timer); cortex_m::peripheral::NVIC::unmask(ral::Interrupt::$timer); } } } impl TimerQueueBackend for $backend_name { type Ticks = u64; fn now() -> Self::Ticks { let gpt = unsafe{ $timer::instance() }; calculate_now( || $period.load(Ordering::Relaxed), || ral::read_reg!(ral::gpt, gpt, CNT) ) } fn set_compare(instant: Self::Ticks) { let gpt = unsafe{ $timer::instance() }; // Set the timer regardless of whether it is multiple periods in the future, // or even already in the past. // The worst thing that can happen is a spurious wakeup, and with a timer // period of half an hour, this is hardly a problem. let ticks_wrapped = instant as u32; ral::write_reg!(ral::gpt, gpt, OCR[1], ticks_wrapped); } fn clear_compare_flag() { let gpt = unsafe{ $timer::instance() }; ral::write_reg!(ral::gpt, gpt, SR, OF2: 1); } fn pend_interrupt() { cortex_m::peripheral::NVIC::pend(ral::Interrupt::$timer); } fn on_interrupt() { let gpt = unsafe{ $timer::instance() }; let (rollover, half_rollover) = ral::read_reg!(ral::gpt, gpt, SR, ROV, OF1); if rollover != 0 { let prev = $period.fetch_add(1, Ordering::Relaxed); ral::write_reg!(ral::gpt, gpt, SR, ROV: 1); assert!(prev % 2 == 1, "Monotonic must have skipped an interrupt!"); } if half_rollover != 0 { let prev = $period.fetch_add(1, Ordering::Relaxed); ral::write_reg!(ral::gpt, gpt, SR, OF1: 1); assert!(prev % 2 == 0, "Monotonic must have skipped an interrupt!"); } } fn timer_queue() -> &'static TimerQueue { &$tq } } }; } #[cfg(feature = "imxrt_gpt1")] make_timer!(Gpt1, Gpt1Backend, GPT1, GPT1_HALFPERIODS, GPT1_TQ); #[cfg(feature = "imxrt_gpt2")] make_timer!(Gpt2, Gpt2Backend, GPT2, GPT2_HALFPERIODS, GPT2_TQ);