feat: SD card async feature

Signed-off-by: Lachezar Lechev <[email protected]>

CHANGELOG.md

@@ -10,6 +10,9 @@ The format is based on [Keep a Changelog] and this project adheres to [Semantic
 
 - Updated to `heapless` ^0.8
 
+### Added
+- __Breaking Change__: SdCard Blocking and Async modes and a news AsyncBlockDevice Trait under the `asynch` feature
+
 ## [Version 0.7.0] - 2024-02-04
 
 ### Changed

Cargo.toml

@@ -14,9 +14,12 @@ version = "0.7.0"
 byteorder = {version = "1", default-features = false}
 defmt = {version = "0.3", optional = true}
 embedded-hal = "1.0.0"
+embedded-hal-async = { version = "1.0.0", optional = true }
 heapless = "^0.8"
 log = {version = "0.4", default-features = false, optional = true}
 
+futures = { version = "0.3", default-features = false, features = ["async-await", "executor"] }
+
 [dev-dependencies]
 chrono = "0.4"
 embedded-hal-bus = "0.1.0"
@@ -26,6 +29,8 @@ hex-literal = "0.4.1"
 sha2 = "0.10"
 
 [features]
-default = ["log"]
+default = ["log", "asynch"]
 defmt-log = ["dep:defmt"]
 log = ["dep:log"]
+# Enable Async support for SdCard and AsyncBlockDevice trait
+asynch = ["dep:embedded-hal-async"]

src/blockdevice.rs

@@ -52,6 +52,24 @@ pub trait BlockDevice {
     fn num_blocks(&self) -> Result<BlockCount, Self::Error>;
 }
 
+/// Represents a block device - a device which can read and write blocks (or
+/// sectors). Only supports devices which are <= 2 TiB in size.
+pub trait AsyncBlockDevice {
+    /// The errors that the `BlockDevice` can return. Must be debug formattable.
+    type Error: core::fmt::Debug;
+    /// Read one or more blocks, starting at the given block index.
+    async fn read(
+        &self,
+        blocks: &mut [Block],
+        start_block_idx: BlockIdx,
+        reason: &str,
+    ) -> Result<(), Self::Error>;
+    /// Write one or more blocks, starting at the given block index.
+    async fn write(&self, blocks: &[Block], start_block_idx: BlockIdx) -> Result<(), Self::Error>;
+    /// Determine how many blocks this device can hold.
+    async fn num_blocks(&self) -> Result<BlockCount, Self::Error>;
+}
+
 impl Block {
     /// All our blocks are a fixed length of 512 bytes. We do not support
     /// 'Advanced Format' Hard Drives with 4 KiB blocks, nor weird old

src/lib.rs

@@ -55,6 +55,12 @@
 
 #![cfg_attr(not(test), no_std)]
 #![deny(missing_docs)]
+#![cfg_attr(feature = "asynch", feature(async_fn_traits))]
+// Since we don't have MSRV we always enable this feature when `asynch` is enabled
+#![cfg_attr(feature = "asynch", feature(async_fn_in_trait))]
+#![cfg_attr(feature = "asynch", allow(stable_features))]
+#![cfg_attr(feature = "asynch", allow(async_fn_in_trait))]
+#![cfg_attr(feature = "asynch", feature(async_closure))]
 
 // ****************************************************************************
 //