dma: allow choices of CHUNK_SIZE

esp-hal/CHANGELOG.md

@@ -17,6 +17,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Use the peripheral ref pattern for `OneShotTimer` and `PeriodicTimer` (#1855)
 
 - Allow DMA to/from psram for esp32s3 (#1827)
+- Allow DMA default chunk size choices. This allows DMA to peripherals to/from psram as drivers don't allow specifying chunk size with DMA descriptors (#1889)
 - DMA buffers now don't require a static lifetime. Make sure to never `mem::forget` an in-progress DMA transfer (consider using `#[deny(clippy::mem_forget)]`) (#1837)
 
 ### Fixed

esp-hal/Cargo.toml

@@ -180,6 +180,12 @@ opsram-8m = []
 ## Use externally connected Octal RAM (16MB).
 opsram-16m = []
 
+#! ### DMA Feature Flags
+## Use a DMA chunk size that is a multiple of 32 bytes.
+dma4064 = []
+## Use a DMA chunk size that is a multiple of 64 bytes.
+dma4032 = []
+
 # This feature is intended for testing; you probably don't want to enable it:
 ci = ["async", "embedded-hal-02", "embedded-io", "ufmt", "defmt", "bluetooth", "place-spi-driver-in-ram"]
 

esp-hal/build.rs

@@ -7,7 +7,7 @@ use std::{
     str::FromStr,
 };
 
-use esp_build::assert_unique_used_features;
+use esp_build::{assert_unique_features, assert_unique_used_features};
 use esp_metadata::{Chip, Config};
 
 #[cfg(debug_assertions)]
@@ -26,6 +26,9 @@ fn main() -> Result<(), Box<dyn Error>> {
         "esp32", "esp32c2", "esp32c3", "esp32c6", "esp32h2", "esp32s2", "esp32s3"
     );
 
+    // Ensure at most one dma chunk size feature is specified.
+    assert_unique_features!("dma4032", "dma4064");
+
     #[cfg(all(
         feature = "flip-link",
         not(any(feature = "esp32c6", feature = "esp32h2"))

esp-hal/src/dma/mod.rs

@@ -281,8 +281,18 @@ pub enum DmaInterrupt {
     RxDone,
 }
 
-/// The default CHUNK_SIZE used for DMA transfers
-pub const CHUNK_SIZE: usize = 4092;
+cfg_if::cfg_if! {
+    if #[cfg(feature = "dma4064")] {
+        /// The default CHUNK_SIZE used for DMA transfers
+        pub const CHUNK_SIZE: usize = 4064;
+    } else if #[cfg(feature = "dma4032")] {
+        /// The default CHUNK_SIZE used for DMA transfers
+        pub const CHUNK_SIZE: usize = 4032;
+    } else {
+        /// The default CHUNK_SIZE used for DMA transfers
+        pub const CHUNK_SIZE: usize = 4092;
+    }
+}
 
 /// Convenience macro to create DMA buffers and descriptors
 ///