Add embedded_dma feature

Author: qwerty19106

CHANGELOG.md

@@ -15,6 +15,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 - Implemented `retain` for `IndexMap` and `IndexSet`.
 - Recover `StableDeref` trait for `pool::object::Object` and `pool::boxed::Box`.
 - Add polyfills for ESP32S2
+- Add `embedded_dma` feature to one can send `Vec`, `pool::object::Object` and `pool::boxed::Box` to DMA as read/write buffers [#362].
 
 ### Changed
 

Cargo.toml

@@ -24,6 +24,7 @@ __trybuild = []
 mpmc_large = []
 # This flag has no version guarantee, the `defmt` dependency can be updated in a patch release
 defmt-impl = ["defmt"]
+embedded-dma = ["dep:embedded-dma"]
 
 [target.thumbv6m-none-eabi.dependencies]
 atomic-polyfill = { version = "1.0.1", optional = true }
@@ -59,6 +60,10 @@ default-features = false
 version = "0.1"
 optional = true
 
+[dependencies.embedded-dma]
+version = "0.2"
+optional = true
+
 [dev-dependencies.ufmt]
 version = "0.1"
 

src/vec.rs

@@ -1181,6 +1181,30 @@ where
     }
 }
 
+#[cfg(feature = "embedded-dma")]
+unsafe impl<T, const N: usize> embedded_dma::ReadTarget for Vec<T, N>
+where
+    T: embedded_dma::ReadTarget,
+{
+    type Word = T::Word;
+
+    // Replace default implementation to return self.len() as buffer size
+    fn as_read_buffer(&self) -> (*const Self::Word, usize) {
+        use ops::Deref;
+        self.deref().as_read_buffer()
+    }
+}
+
+#[cfg(feature = "embedded-dma")]
+unsafe impl<T, const N: usize> embedded_dma::WriteTarget for Vec<T, N>
+where
+    T: embedded_dma::WriteTarget,
+{
+    type Word = T::Word;
+
+    // Use default implementation to return N as buffer size
+}
+
 #[cfg(test)]
 mod tests {
     use crate::Vec;