From d8821cfd41eb1776b904a5766be43f242af938f7 Mon Sep 17 00:00:00 2001
From: kalkyl <henrik.alser@me.com>
Date: Sat, 10 Dec 2022 12:57:45 +0100
Subject: [PATCH] Feature gate critical-section-impl

---
 embassy-rp/Cargo.toml       | 5 ++++-
 embassy-rp/src/lib.rs       | 2 ++
 embassy-rp/src/multicore.rs | 4 +++-
 examples/rp/Cargo.toml      | 2 +-
 tests/rp/Cargo.toml         | 2 +-
 5 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/embassy-rp/Cargo.toml b/embassy-rp/Cargo.toml
index 07cd1bc1..694f0dc7 100644
--- a/embassy-rp/Cargo.toml
+++ b/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 }
diff --git a/embassy-rp/src/lib.rs b/embassy-rp/src/lib.rs
index 9a2fb7fc..2cd99f45 100644
--- a/embassy-rp/src/lib.rs
+++ b/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;
diff --git a/embassy-rp/src/multicore.rs b/embassy-rp/src/multicore.rs
index dd3b70a6..cc5c192b 100644
--- a/embassy-rp/src/multicore.rs
+++ b/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.
diff --git a/examples/rp/Cargo.toml b/examples/rp/Cargo.toml
index bd624a32..34a2d36d 100644
--- a/examples/rp/Cargo.toml
+++ b/examples/rp/Cargo.toml
@@ -9,7 +9,7 @@ license = "MIT OR Apache-2.0"
 embassy-sync = { version = "0.1.0", path = "../../embassy-sync", features = ["defmt"] }
 embassy-executor = { version = "0.1.0", path = "../../embassy-executor", features = ["defmt", "integrated-timers"] }
 embassy-time = { version = "0.1.0", path = "../../embassy-time", features = ["defmt", "defmt-timestamp-uptime"] }
-embassy-rp = { version = "0.1.0", path = "../../embassy-rp", features = ["defmt", "unstable-traits", "nightly", "unstable-pac", "time-driver"] }
+embassy-rp = { version = "0.1.0", path = "../../embassy-rp", features = ["defmt", "unstable-traits", "nightly", "unstable-pac", "time-driver", "critical-section-impl"] }
 embassy-usb = { version = "0.1.0", path = "../../embassy-usb", features = ["defmt"] }
 embassy-net = { version = "0.1.0", path = "../../embassy-net", features = ["defmt", "nightly", "tcp", "dhcpv4", "medium-ethernet", "pool-16"] }
 embassy-futures = { version = "0.1.0", path = "../../embassy-futures" }
diff --git a/tests/rp/Cargo.toml b/tests/rp/Cargo.toml
index ffde4c7f..572a9ce8 100644
--- a/tests/rp/Cargo.toml
+++ b/tests/rp/Cargo.toml
@@ -8,7 +8,7 @@ license = "MIT OR Apache-2.0"
 embassy-sync = { version = "0.1.0", path = "../../embassy-sync", features = ["defmt"] }
 embassy-executor = { version = "0.1.0", path = "../../embassy-executor", features = ["defmt", "integrated-timers"] }
 embassy-time = { version = "0.1.0", path = "../../embassy-time", features = ["defmt"] }
-embassy-rp = { version = "0.1.0", path = "../../embassy-rp", features = ["nightly", "defmt", "unstable-pac", "unstable-traits", "time-driver"]  }
+embassy-rp = { version = "0.1.0", path = "../../embassy-rp", features = ["nightly", "defmt", "unstable-pac", "unstable-traits", "time-driver", "critical-section-impl"]  }
 embassy-futures = { version = "0.1.0", path = "../../embassy-futures" }
 
 defmt = "0.3.0"