3 files changed, 82 insertions, 4 deletions

diff --git a/embassy-executor/Cargo.toml b/embassy-executor/Cargo.toml
index b6b156c9f..d6fe8ee8b 100644
--- a/embassy-executor/Cargo.toml
+++ b/embassy-executor/Cargo.toml
@@ -40,7 +40,7 @@ critical-section = "1.1"
 
 document-features = "0.2.7"
 
-# needed for riscv
+# needed for riscv and avr
 # remove when https://github.com/rust-lang/rust/pull/114499 is merged
 portable-atomic = { version = "1.5", optional = true }
 
@@ -51,6 +51,9 @@ cortex-m = { version = "0.7.6", optional = true }
 wasm-bindgen = { version = "0.2.82", optional = true }
 js-sys = { version = "0.3", optional = true }
 
+# arch-avr dependencies
+avr-device = { version = "0.5.3", optional = true }
+
 [dev-dependencies]
 critical-section = { version = "1.1", features = ["std"] }
 
@@ -78,6 +81,8 @@ arch-cortex-m = ["_arch", "dep:cortex-m"]
 arch-riscv32 = ["_arch", "dep:portable-atomic"]
 ## WASM
 arch-wasm = ["_arch", "dep:wasm-bindgen", "dep:js-sys"]
+## AVR
+arch-avr = ["_arch", "dep:portable-atomic", "dep:avr-device"]
 
 #! ### Executor
 
@@ -88,11 +93,11 @@ executor-interrupt = []
 
 #! ### Task Arena Size
 #! Sets the [task arena](#task-arena) size. Necessary if you’re not using `nightly`.
-#! 
+#!
 #! <details>
 #!  <summary>Preconfigured Task Arena Sizes:</summary>
 #! <!-- rustdoc requires the following blank line for the feature list to render correctly! -->
-#! 
+#!
 
 # BEGIN AUTOGENERATED CONFIG FEATURES
 # Generated by gen_config.py. DO NOT EDIT.
diff --git a/embassy-executor/src/arch/avr.rs b/embassy-executor/src/arch/avr.rs
new file mode 100644
index 000000000..70085d04d
--- /dev/null
+++ b/embassy-executor/src/arch/avr.rs
@@ -0,0 +1,72 @@
+#[cfg(feature = "executor-interrupt")]
+compile_error!("`executor-interrupt` is not supported with `arch-avr`.");
+
+#[cfg(feature = "executor-thread")]
+pub use thread::*;
+#[cfg(feature = "executor-thread")]
+mod thread {
+    use core::marker::PhantomData;
+
+    pub use embassy_executor_macros::main_avr as main;
+    use portable_atomic::{AtomicBool, Ordering};
+
+    use crate::{raw, Spawner};
+
+    static SIGNAL_WORK_THREAD_MODE: AtomicBool = AtomicBool::new(false);
+
+    #[export_name = "__pender"]
+    fn __pender(_context: *mut ()) {
+        SIGNAL_WORK_THREAD_MODE.store(true, Ordering::SeqCst);
+    }
+
+    /// avr Executor
+    pub struct Executor {
+        inner: raw::Executor,
+        not_send: PhantomData<*mut ()>,
+    }
+
+    impl Executor {
+        /// Create a new Executor.
+        pub fn new() -> Self {
+            Self {
+                inner: raw::Executor::new(core::ptr::null_mut()),
+                not_send: PhantomData,
+            }
+        }
+
+        /// Run the executor.
+        ///
+        /// The `init` closure is called with a [`Spawner`] that spawns tasks on
+        /// this executor. Use it to spawn the initial task(s). After `init` returns,
+        /// the executor starts running the tasks.
+        ///
+        /// To spawn more tasks later, you may keep copies of the [`Spawner`] (it is `Copy`),
+        /// for example by passing it as an argument to the initial tasks.
+        ///
+        /// This function requires `&'static mut self`. This means you have to store the
+        /// Executor instance in a place where it'll live forever and grants you mutable
+        /// access. There's a few ways to do this:
+        ///
+        /// - a [StaticCell](https://docs.rs/static_cell/latest/static_cell/) (safe)
+        /// - a `static mut` (unsafe)
+        /// - a local variable in a function you know never returns (like `fn main() -> !`), upgrading its lifetime with `transmute`. (unsafe)
+        ///
+        /// This function never returns.
+        pub fn run(&'static mut self, init: impl FnOnce(Spawner)) -> ! {
+            init(self.inner.spawner());
+
+            loop {
+                unsafe {
+                    avr_device::interrupt::disable();
+                    if !SIGNAL_WORK_THREAD_MODE.swap(false, Ordering::SeqCst) {
+                        avr_device::interrupt::enable();
+                        avr_device::asm::sleep();
+                    } else {
+                        avr_device::interrupt::enable();
+                        self.inner.poll();
+                    }
+                }
+            }
+        }
+    }
+}
diff --git a/embassy-executor/src/lib.rs b/embassy-executor/src/lib.rs
index eea118ade..6a2e493a2 100644
--- a/embassy-executor/src/lib.rs
+++ b/embassy-executor/src/lib.rs
@@ -23,9 +23,10 @@ macro_rules! check_at_most_one {
         check_at_most_one!(@amo [$($f)*] [$($f)*] []);
     };
 }
-check_at_most_one!("arch-cortex-m", "arch-riscv32", "arch-std", "arch-wasm",);
+check_at_most_one!("arch-avr", "arch-cortex-m", "arch-riscv32", "arch-std", "arch-wasm",);
 
 #[cfg(feature = "_arch")]
+#[cfg_attr(feature = "arch-avr", path = "arch/avr.rs")]
 #[cfg_attr(feature = "arch-cortex-m", path = "arch/cortex_m.rs")]
 #[cfg_attr(feature = "arch-riscv32", path = "arch/riscv32.rs")]
 #[cfg_attr(feature = "arch-std", path = "arch/std.rs")]