Add setting of priority to interrupts

5 files changed, 107 insertions, 44 deletions

diff --git a/rtic-monotonics/src/lib.rs b/rtic-monotonics/src/lib.rs
index fab0b2d..04ce4e2 100644
--- a/rtic-monotonics/src/lib.rs
+++ b/rtic-monotonics/src/lib.rs
@@ -26,6 +26,42 @@ pub mod rp2040;
 ))]
 pub mod nrf;
 
+#[allow(dead_code)]
+pub(crate) const fn cortex_logical2hw(logical: u8, nvic_prio_bits: u8) -> u8 {
+    ((1 << nvic_prio_bits) - logical) << (8 - nvic_prio_bits)
+}
+
+#[cfg(any(
+    feature = "rp2040",
+    feature = "nrf52810",
+    feature = "nrf52811",
+    feature = "nrf52832",
+    feature = "nrf52833",
+    feature = "nrf52840",
+    feature = "nrf5340-app",
+    feature = "nrf5340-net",
+    feature = "nrf9160",
+))]
+pub(crate) unsafe fn set_monotonic_prio(
+    prio_bits: u8,
+    interrupt: impl cortex_m::interrupt::InterruptNumber,
+) {
+    extern "C" {
+        static RTIC_ASYNC_MAX_LOGICAL_PRIO: u8;
+    }
+
+    let max_prio = RTIC_ASYNC_MAX_LOGICAL_PRIO.max(1).min(1 << prio_bits);
+
+    let hw_prio = crate::cortex_logical2hw(max_prio, prio_bits);
+
+    // We take ownership of the entire IRQ and all settings to it, we only change settings
+    // for the IRQ we control.
+    // This will also compile-error in case the NVIC changes in size.
+    let mut nvic: cortex_m::peripheral::NVIC = core::mem::transmute(());
+
+    nvic.set_priority(interrupt, hw_prio);
+}
+
 /// This marker is implemented on an interrupt token to enforce that the right tokens
 /// are given to the correct monotonic implementation.
 ///
diff --git a/rtic-monotonics/src/nrf/rtc.rs b/rtic-monotonics/src/nrf/rtc.rs
index 724c477..03610c0 100644
--- a/rtic-monotonics/src/nrf/rtc.rs
+++ b/rtic-monotonics/src/nrf/rtc.rs
@@ -5,19 +5,22 @@
 //! ```
 //! use rtic_monotonics::nrf::rtc::*;
 //!
-//! # async fn usage() {
-//! # let rtc = unsafe { core::mem::transmute(()) };
-//! // Generate the required token
-//! let token = rtic_monotonics::create_nrf_rtc0_monotonic_token!();
+//! fn init() {
+//!     # // This is normally provided by the selected PAC
+//!     # let rtc = unsafe { core::mem::transmute(()) };
+//!     // Generate the required token
+//!     let token = rtic_monotonics::create_nrf_rtc0_monotonic_token!();
 //!
-//! // Start the monotonic
-//! Rtc0::start(rtc, token);
+//!     // Start the monotonic
+//!     Rtc0::start(rtc, token);
+//! }
 //!
-//! loop {
-//!      // Use the monotonic
-//!      Rtc0::delay(100.millis()).await;
+//! async fn usage() {
+//!     loop {
+//!          // Use the monotonic
+//!          Rtc0::delay(100.millis()).await;
+//!     }
 //! }
-//! # }
 //! ```
 
 #[cfg(feature = "nrf52810")]
@@ -106,7 +109,13 @@ macro_rules! make_rtc {
 
                 $tq.initialize(Self {});
 
-                unsafe { pac::NVIC::unmask(Interrupt::$rtc) };
+                // SAFETY: We take full ownership of the peripheral and interrupt vector,
+                // plus we are not using any external shared resources so we won't impact
+                // basepri/source masking based critical sections.
+                unsafe {
+                    crate::set_monotonic_prio(pac::NVIC_PRIO_BITS, Interrupt::$rtc);
+                    pac::NVIC::unmask(Interrupt::$rtc);
+                }
             }
 
             /// Used to access the underlying timer queue
diff --git a/rtic-monotonics/src/nrf/timer.rs b/rtic-monotonics/src/nrf/timer.rs
index ad490cc..db5316f 100644
--- a/rtic-monotonics/src/nrf/timer.rs
+++ b/rtic-monotonics/src/nrf/timer.rs
@@ -5,19 +5,22 @@
 //! ```
 //! use rtic_monotonics::nrf::timer::*;
 //!
-//! # async fn usage() {
-//! # let timer = unsafe { core::mem::transmute(()) };
-//! // Generate the required token
-//! let token = rtic_monotonics::create_nrf_timer0_monotonic_token!();
+//! fn init() {
+//!     # // This is normally provided by the selected PAC
+//!     # let timer = unsafe { core::mem::transmute(()) };
+//!     // Generate the required token
+//!     let token = rtic_monotonics::create_nrf_timer0_monotonic_token!();
 //!
-//! // Start the monotonic
-//! Timer0::start(timer, token);
+//!     // Start the monotonic
+//!     Timer0::start(timer, token);
+//! }
 //!
-//! loop {
-//!      // Use the monotonic
-//!      Timer0::delay(100.millis()).await;
+//! async fn usage() {
+//!     loop {
+//!          // Use the monotonic
+//!          Timer0::delay(100.millis()).await;
+//!     }
 //! }
-//! # }
 //! ```
 
 use super::super::Monotonic;
@@ -135,7 +138,13 @@ macro_rules! make_timer {
                 timer.events_compare[0].write(|w| w);
                 timer.events_compare[1].write(|w| w);
 
-                unsafe { pac::NVIC::unmask(Interrupt::$timer) };
+                // SAFETY: We take full ownership of the peripheral and interrupt vector,
+                // plus we are not using any external shared resources so we won't impact
+                // basepri/source masking based critical sections.
+                unsafe {
+                    crate::set_monotonic_prio(pac::NVIC_PRIO_BITS, Interrupt::$timer);
+                    pac::NVIC::unmask(Interrupt::$timer);
+                }
             }
 
             /// Used to access the underlying timer queue
diff --git a/rtic-monotonics/src/rp2040.rs b/rtic-monotonics/src/rp2040.rs
index 5e880cd..c656afc 100644
--- a/rtic-monotonics/src/rp2040.rs
+++ b/rtic-monotonics/src/rp2040.rs
@@ -5,20 +5,23 @@
 //! ```
 //! use rtic_monotonics::rp2040::*;
 //!
-//! # async fn usage() {
-//! # let timer = unsafe { core::mem::transmute(()) };
-//! # let mut resets = unsafe { core::mem::transmute(()) };
-//! // Generate the required token
-//! let token = rtic_monotonics::create_rp2040_monotonic_token!();
+//! fn init() {
+//!     # // This is normally provided by the selected PAC
+//!     # let timer = unsafe { core::mem::transmute(()) };
+//!     # let mut resets = unsafe { core::mem::transmute(()) };
+//!     // Generate the required token
+//!     let token = rtic_monotonics::create_rp2040_monotonic_token!();
 //!
-//! // Start the monotonic
-//! Timer::start(timer, &mut resets, token);
+//!     // Start the monotonic
+//!     Timer::start(timer, &mut resets, token);
+//! }
 //!
-//! loop {
-//!      // Use the monotonic
-//!      Timer::delay(100.millis()).await;
+//! async fn usage() {
+//!     loop {
+//!          // Use the monotonic
+//!          Timer::delay(100.millis()).await;
+//!     }
 //! }
-//! # }
 //! ```
 
 use super::Monotonic;
@@ -43,7 +46,10 @@ impl Timer {
 
         TIMER_QUEUE.initialize(Self {});
 
-        unsafe { NVIC::unmask(Interrupt::TIMER_IRQ_0) };
+        unsafe {
+            crate::set_monotonic_prio(rp2040_pac::NVIC_PRIO_BITS, Interrupt::TIMER_IRQ_0);
+            NVIC::unmask(Interrupt::TIMER_IRQ_0);
+        }
     }
 
     fn timer() -> &'static timer::RegisterBlock {
diff --git a/rtic-monotonics/src/systick.rs b/rtic-monotonics/src/systick.rs
index f1d49da..6a28a11 100644
--- a/rtic-monotonics/src/systick.rs
+++ b/rtic-monotonics/src/systick.rs
@@ -6,19 +6,22 @@
 //! ```
 //! use rtic_monotonics::systick::*;
 //!
-//! # async fn usage() {
-//! # let systick = unsafe { core::mem::transmute(()) };
-//! // Generate the required token
-//! let systick_token = rtic_monotonics::create_systick_token!();
+//! fn init() {
+//!     # // This is normally provided by the selected PAC
+//!     # let systick = unsafe { core::mem::transmute(()) };
+//!     // Generate the required token
+//!     let systick_token = rtic_monotonics::create_systick_token!();
 //!
-//! // Start the monotonic
-//! Systick::start(systick, 12_000_000, systick_token);
+//!     // Start the monotonic
+//!     Systick::start(systick, 12_000_000, systick_token);
+//! }
 //!
-//! loop {
-//!      // Use the monotonic
-//!      Systick::delay(100.millis()).await;
+//! async fn usage() {
+//!     loop {
+//!          // Use the monotonic
+//!          Systick::delay(100.millis()).await;
+//!     }
 //! }
-//! # }
 //! ```
 
 use super::Monotonic;