From e4d9284e258a34b10cac2eff47ca2ccb470b460c Mon Sep 17 00:00:00 2001
From: Emil Fresk <emil.fresk@gmail.com>
Date: Sat, 11 Mar 2023 20:47:39 +0100
Subject: [PATCH] rtic-monotonics: Add interrupt tokens to make sure users bind
 interrupts

---
 rtic-monotonics/CHANGELOG.md   |  2 ++
 rtic-monotonics/src/lib.rs     | 10 ++++++++++
 rtic-monotonics/src/rp2040.rs  | 19 +++++++++++++++++--
 rtic-monotonics/src/systick.rs | 17 ++++++++++++++++-
 rtic/examples/async-delay.rs   |  5 ++---
 rtic/examples/async-timeout.rs |  5 ++---
 6 files changed, 49 insertions(+), 9 deletions(-)

diff --git a/rtic-monotonics/CHANGELOG.md b/rtic-monotonics/CHANGELOG.md
index d3a9d846ee..d061bd377b 100644
--- a/rtic-monotonics/CHANGELOG.md
+++ b/rtic-monotonics/CHANGELOG.md
@@ -9,6 +9,8 @@ For each category, *Added*, *Changed*, *Fixed* add new entries at the top!
 
 ### Added
 
+- Interrupt tokens for `Systick` and `rp2040` to make sure an interrupt handler exists
+
 ### Changed
 
 ### Fixed
diff --git a/rtic-monotonics/src/lib.rs b/rtic-monotonics/src/lib.rs
index a4a1f428ce..6143fd0e5e 100644
--- a/rtic-monotonics/src/lib.rs
+++ b/rtic-monotonics/src/lib.rs
@@ -13,3 +13,13 @@ pub mod systick;
 
 #[cfg(feature = "rp2040")]
 pub mod rp2040;
+
+/// This marker is implemented on an interrupt token to enforce that the right tokens
+/// are given to the correct monotonic implementation.
+///
+/// This trait is implemented by this crate and not intended for user implementation.
+///
+/// # Safety
+///
+/// This is only safely implemented by this crate.
+pub unsafe trait InterruptToken<Periperhal> {}
diff --git a/rtic-monotonics/src/rp2040.rs b/rtic-monotonics/src/rp2040.rs
index e42c148e4c..039b117e71 100644
--- a/rtic-monotonics/src/rp2040.rs
+++ b/rtic-monotonics/src/rp2040.rs
@@ -4,14 +4,18 @@ use super::Monotonic;
 pub use super::{TimeoutError, TimerQueue};
 use core::future::Future;
 pub use fugit::ExtU64;
-use rp2040_pac::{timer, Interrupt, RESETS, TIMER};
+use rp2040_pac::{timer, Interrupt, NVIC, RESETS, TIMER};
 
 /// Timer implementing `rtic_monotonic::Monotonic` which runs at 1 MHz.
 pub struct Timer;
 
 impl Timer {
     /// Start a `Monotonic` based on RP2040's Timer.
-    pub fn start(timer: TIMER, resets: &mut RESETS) {
+    pub fn start(
+        timer: TIMER,
+        resets: &mut RESETS,
+        _interrupt_token: impl crate::InterruptToken<Self>,
+    ) {
         resets.reset.modify(|_, w| w.timer().clear_bit());
         while resets.reset_done.read().timer().bit_is_clear() {}
         timer.inte.modify(|_, w| w.alarm_0().set_bit());
@@ -134,10 +138,21 @@ impl embedded_hal_async::delay::DelayUs for Timer {
 #[macro_export]
 macro_rules! make_rp2040_monotonic_handler {
     () => {
+    {
         #[no_mangle]
         #[allow(non_snake_case)]
         unsafe extern "C" fn TIMER_IRQ_0() {
             rtic_monotonics::rp2040::Timer::__tq().on_monotonic_interrupt();
         }
+
+        pub struct Rp2040Token;
+
+        unsafe impl rtic_monotonics::InterruptToken<rtic_monotonics::rp2040::Timer>
+            for Rp2040Token
+        {
+        }
+
+        Rp2040Token
+    }
     };
 }
diff --git a/rtic-monotonics/src/systick.rs b/rtic-monotonics/src/systick.rs
index 691d7c764f..feefc7ea05 100644
--- a/rtic-monotonics/src/systick.rs
+++ b/rtic-monotonics/src/systick.rs
@@ -36,7 +36,11 @@ impl Systick {
     /// `sysclk` and `TIMER_HZ`.
     ///
     /// Note: Give the return value to `TimerQueue::initialize()` to initialize the timer queue.
-    pub fn start(mut systick: cortex_m::peripheral::SYST, sysclk: u32) {
+    pub fn start(
+        mut systick: cortex_m::peripheral::SYST,
+        sysclk: u32,
+        _interrupt_token: impl crate::InterruptToken<Self>,
+    ) {
         // + TIMER_HZ / 2 provides round to nearest instead of round to 0.
         // - 1 as the counter range is inclusive [0, reload]
         let reload = (sysclk + TIMER_HZ / 2) / TIMER_HZ - 1;
@@ -154,10 +158,21 @@ impl embedded_hal_async::delay::DelayUs for Systick {
 #[macro_export]
 macro_rules! make_systick_handler {
     () => {
+    {
         #[no_mangle]
         #[allow(non_snake_case)]
         unsafe extern "C" fn SysTick() {
             rtic_monotonics::systick::Systick::__tq().on_monotonic_interrupt();
         }
+
+        pub struct SystickToken;
+
+        unsafe impl rtic_monotonics::InterruptToken<rtic_monotonics::systick::Systick>
+            for SystickToken
+        {
+        }
+
+        SystickToken
+    }
     };
 }
diff --git a/rtic/examples/async-delay.rs b/rtic/examples/async-delay.rs
index c163a3e692..7b3667b094 100644
--- a/rtic/examples/async-delay.rs
+++ b/rtic/examples/async-delay.rs
@@ -14,8 +14,6 @@ mod app {
     use cortex_m_semihosting::{debug, hprintln};
     use rtic_monotonics::systick::*;
 
-    rtic_monotonics::make_systick_handler!();
-
     #[shared]
     struct Shared {}
 
@@ -26,7 +24,8 @@ mod app {
     fn init(cx: init::Context) -> (Shared, Local) {
         hprintln!("init");
 
-        Systick::start(cx.core.SYST, 12_000_000);
+        let systick_token = rtic_monotonics::make_systick_handler!();
+        Systick::start(cx.core.SYST, 12_000_000, systick_token);
 
         foo::spawn().ok();
         bar::spawn().ok();
diff --git a/rtic/examples/async-timeout.rs b/rtic/examples/async-timeout.rs
index 384c8886fa..e07e9c6f67 100644
--- a/rtic/examples/async-timeout.rs
+++ b/rtic/examples/async-timeout.rs
@@ -17,8 +17,6 @@ mod app {
     use futures::{future::FutureExt, select_biased};
     use rtic_monotonics::Monotonic;
 
-    rtic_monotonics::make_systick_handler!();
-
     #[shared]
     struct Shared {}
 
@@ -29,7 +27,8 @@ mod app {
     fn init(cx: init::Context) -> (Shared, Local) {
         hprintln!("init");
 
-        Systick::start(cx.core.SYST, 12_000_000);
+        let systick_token = rtic_monotonics::make_systick_handler!();
+        Systick::start(cx.core.SYST, 12_000_000, systick_token);
 
         foo::spawn().ok();