Use stable release channel for RISC-V targets

.github/workflows/ci.yml

@@ -38,9 +38,7 @@ jobs:
 
       # Install the Rust toolchain for RISC-V devices:
       - if: ${{ !contains(fromJson('["esp32", "esp32s2", "esp32s3"]'), matrix.mcu) }}
-        uses: dtolnay/rust-toolchain@v1
-        with:
-          toolchain: nightly-2024-06-01 # TODO: Remove date when able
+        uses: dtolnay/rust-toolchain@stable
 
       # Install the Rust toolchain for Xtensa devices:
       - if: ${{ contains(fromJson('["esp32", "esp32s2", "esp32s3"]'), matrix.mcu) }}

embassy/Cargo.toml

@@ -16,7 +16,7 @@ embassy-time     = { version = "0.3.2",  features = ["generic-queue-8"] }
 esp-backtrace    = { version = "0.14.1", features = ["{{ mcu }}", "defmt", "exception-handler", "panic-handler"] }
 esp-hal          = { version = "0.20.1", features = ["{{ mcu }}", "defmt", "async"] }
 esp-hal-embassy  = { version = "0.3.0",  features = ["{{ mcu }}", "defmt"] }
-static_cell      = { version = "2.1.0",  features = ["nightly"] }
+static_cell      = "2.1.0"
 
 [profile.release]
 debug         = true  # Debug info is useful, and does not affect the size of the final binary

embassy/pre-script.rhai

@@ -13,6 +13,6 @@ if mcu in ["esp32", "esp32s2", "esp32s3"] {
     };
 
     variable::set("arch",        "riscv");
-    variable::set("toolchain",   "nightly-2024-06-01"); // TODO: Remove date when able
+    variable::set("toolchain",   "stable");
     variable::set("rust_target", `riscv32${extensions}-unknown-none-elf`);
 }

embassy/src/lib.rs

@@ -1 +1,20 @@
 #![no_std]
+
+/// Convert a `T` to a `&'static mut T`.
+///
+/// The macro declares a `static StaticCell` and then initializes it when run,
+/// returning the `&'static mut`. Therefore, each instance can only be run once.
+/// Next runs will panic. The `static` can additionally be decorated with
+/// attributes, such as `#[link_section]`, `#[used]`, et al.
+#[macro_export]
+macro_rules! make_static {
+    ( $t:ty, $val:expr) => ($crate::make_static!($t, $val, ));
+    ( $t:ty, $val:expr, $(#[$m:meta])* ) => {{
+        $(#[$m])*
+        static STATIC_CELL: ::static_cell::StaticCell<$t> = ::static_cell::StaticCell::new();
+        #[deny(unused_attributes)]
+        let x = STATIC_CELL.uninit().write(($val));
+
+        x
+    }};
+}