Use critical_section crate

embassy-rp/Cargo.toml

@@ -20,6 +20,7 @@ defmt = { version = "0.2.0", optional = true }
 log = { version = "0.4.11", optional = true }
 cortex-m-rt = "0.6.13"
 cortex-m = "0.7.1"
+critical-section = "0.2.0"
 
 rp2040-pac2 = { git = "https://github.com/Dirbaio/rp2040-pac", rev="254f4677937801155ca3cb17c7bb9d38eb62683e", features = ["rt"] }
 embedded-hal = { version = "0.2.4", features = [ "unproven" ] }

embassy-rp/src/interrupt.rs

@@ -8,7 +8,6 @@ use core::sync::atomic::{compiler_fence, Ordering};
 use crate::pac::NVIC_PRIO_BITS;
 
 // Re-exports
-pub use cortex_m::interrupt::{CriticalSection, Mutex};
 pub use embassy::interrupt::{declare, take, Interrupt};
 
 #[derive(Debug, Copy, Clone, Eq, PartialEq, Ord, PartialOrd)]
@@ -47,35 +46,6 @@ impl From<Priority> for u8 {
     }
 }
 
-#[inline]
-pub fn free<F, R>(f: F) -> R
-where
-    F: FnOnce(&CriticalSection) -> R,
-{
-    unsafe {
-        // TODO: assert that we're in privileged level
-        // Needed because disabling irqs in non-privileged level is a noop, which would break safety.
-
-        let primask: u32;
-        asm!("mrs {}, PRIMASK", out(reg) primask);
-
-        asm!("cpsid i");
-
-        // Prevent compiler from reordering operations inside/outside the critical section.
-        compiler_fence(Ordering::SeqCst);
-
-        let r = f(&CriticalSection::new());
-
-        compiler_fence(Ordering::SeqCst);
-
-        if primask & 1 == 0 {
-            asm!("cpsie i");
-        }
-
-        r
-    }
-}
-
 mod irqs {
     use super::*;