Fix up interrupt docs

esp-hal/src/interrupt/mod.rs

@@ -1,27 +1,18 @@
 //! # Interrupt support
 //!
-//! ## Overview
-//! The `interrupt` driver is a crucial module for ESP chips. Its primary
-//! purpose is to manage and handle interrupts, which are asynchronous events
-//! requiring immediate attention from the CPU. Interrupts are essential in
-//! various applications, such as real-time tasks, I/O communications, and
-//! handling external events like hardware signals.
-//!
-//! The core functionality of the `interrupt` driver revolves around the
-//! management of interrupts. When an interrupt occurs, it temporarily stops the
-//! ongoing CPU operations, saves its current state, and starts executing the
-//! corresponding interrupt service routine (ISR). The interrupt service routine
-//! is a user-defined function that performs the necessary actions to handle the
-//! specific interrupt. Once the ISR is executed, the driver restores the saved
-//! CPU state and resumes normal program execution.
-//!
-//! In scenarios where multiple interrupts may occur simultaneously, the
-//! interrupt driver determines the `priority` of each interrupt. This
-//! prioritization ensures that critical or high-priority tasks are handled
-//! first. It helps prevent delays in time-sensitive applications and allows the
-//! system to allocate resources efficiently. This functionality is provided and
-//! implemented by the `priority` enum.
+//! Interrupt support functionality depends heavily on the features enabled.
 //!
+//! When the `vectored` feature is enabled, the
+//! [`enable`] method will map interrupt to a CPU
+//! interrupt, and handle the `vector`ing to the peripheral interrupt, for
+//! example `UART0`.
+//!
+//! It is also possible, but not recommended, to bind an interrupt directly to a
+//! CPU interrupt. This can offer lower latency, at the cost of more complexity
+//! in the interrupt handler.
+//!
+//! The `vectored` reserves a number of CPU interrupts, which cannot be used see
+//! [`RESERVED_INTERRUPTS`].
 //!
 //! ## Example
 //! ```no_run
@@ -30,12 +21,20 @@
 //!     ...
 //!     critical_section::with(|cs| SWINT.borrow_ref_mut(cs).replace(sw_int));
 //!
+//!     // enable the interrupt
 //!     interrupt::enable(
 //!         peripherals::Interrupt::FROM_CPU_INTR0,
 //!         interrupt::Priority::Priority1,
 //!     )
 //!     .unwrap();
 //!
+//!     // trigger the interrupt
+//!     SWINT
+//!        .borrow_ref_mut(cs)
+//!        .as_mut()
+//!        .unwrap()
+//!        .raise(SoftwareInterrupt::SoftwareInterrupt0);
+//!
 //!     loop {}
 //! }
 //!

esp-hal/src/interrupt/riscv.rs

@@ -781,7 +781,7 @@ mod plic {
     pub(super) unsafe extern "C" fn _handle_priority() -> u32 {
         use super::mcause;
         let plic_mxint_pri_ptr = PLIC_MXINT0_PRI_REG as *mut u32;
-        let interrupt_id: isize = mcause::read().code().try_into().unwrap(); // MSB is whether its exception or interrupt.
+        let interrupt_id: isize = unwrap!(mcause::read().code().try_into()); // MSB is whether its exception or interrupt.
         let interrupt_priority = plic_mxint_pri_ptr.offset(interrupt_id).read_volatile();
 
         let thresh_reg = PLIC_MXINT_THRESH_REG as *mut u32;