Feature gate critical-section-impl

embassy-rp/Cargo.toml

@@ -15,6 +15,9 @@ flavors = [
 [features]
 defmt = ["dep:defmt", "embassy-usb-driver?/defmt", "embassy-hal-common/defmt"]
 
+# critical section that is safe for multicore use
+critical-section-impl = ["critical-section/restore-state-u8"]
+
 # Reexport the PAC for the currently enabled chip at `embassy_rp::pac`.
 # This is unstable because semver-minor (non-breaking) releases of embassy-rp may major-bump (breaking) the PAC version.
 # If this is an issue for you, you're encouraged to directly depend on a fixed version of the PAC.
@@ -50,7 +53,7 @@ nb = "1.0.0"
 cfg-if = "1.0.0"
 cortex-m-rt = ">=0.6.15,<0.8"
 cortex-m = "0.7.6"
-critical-section = { version = "1.1", features = ["restore-state-u8"] }
+critical-section = "1.1"
 futures = { version = "0.3.17", default-features = false, features = ["async-await"] }
 chrono = { version = "0.4", default-features = false, optional = true }
 embedded-io = { version = "0.4.0", features = ["async"], optional = true }

embassy-rp/src/lib.rs

@@ -5,7 +5,9 @@
 // This mod MUST go first, so that the others see its macros.
 pub(crate) mod fmt;
 
+#[cfg(feature = "critical-section-impl")]
 mod critical_section_impl;
+
 mod intrinsics;
 
 pub mod adc;

embassy-rp/src/multicore.rs

@@ -4,6 +4,9 @@
 //! It provides functionality for setting up the stack, and starting core1.
 //!
 //! The entrypoint for core1 can be any function that never returns, including closures.
+//!
+//! Enable the `critical-section-impl` feature in embassy-rp when sharing data across cores using
+//! the `embassy-sync` primitives and `CriticalSectionRawMutex`.
 
 use core::mem::ManuallyDrop;
 use core::sync::atomic::{compiler_fence, Ordering};
@@ -57,7 +60,6 @@ fn install_stack_guard(stack_bottom: *mut usize) {
 #[inline(always)]
 fn core1_setup(stack_bottom: *mut usize) {
     install_stack_guard(stack_bottom);
-    // TODO: irq priorities
 }
 
 /// Multicore execution management.