From 2bcf2af62fa4ff5092bbbc6d2790beb3c04e8116 Mon Sep 17 00:00:00 2001
From: Richard Meadows <962920+richardeoin@users.noreply.github.com>
Date: Wed, 31 Jan 2024 21:43:06 +0100
Subject: [PATCH] Add note where TARGET_BUFFER should be initialised (but is
 not)

---
 examples/dma.rs         | 3 +++
 examples/mdma_bursts.rs | 5 ++++-
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/examples/dma.rs b/examples/dma.rs
index 730a2c5b..c1ec1762 100644
--- a/examples/dma.rs
+++ b/examples/dma.rs
@@ -71,6 +71,9 @@ fn main() -> ! {
     // Save a copy on the stack so we can check it later
     let source_buffer_cloned = *source_buffer;
 
+    // NOTE(unsafe): TARGET_BUFFER must also be initialised to prevent undefined
+    // behaviour (taking a mutable reference to uninitialised memory)
+
     // Setup DMA
     //
     // We need to specify the transfer size with a type annotation
diff --git a/examples/mdma_bursts.rs b/examples/mdma_bursts.rs
index 784fcb74..bfcd6083 100644
--- a/examples/mdma_bursts.rs
+++ b/examples/mdma_bursts.rs
@@ -61,7 +61,7 @@ fn main() -> ! {
     info!("");
 
     // Initialise the source buffer without taking any references to
-    // uninitialisated memory
+    // uninitialised memory
     let _source_buffer: &'static mut [u32; 200] = {
         let buf: &mut [MaybeUninit<u32>; 200] = unsafe {
             &mut *(core::ptr::addr_of_mut!(SOURCE_BUFFER)
@@ -76,6 +76,9 @@ fn main() -> ! {
         unsafe { SOURCE_BUFFER.assume_init_mut() }
     };
 
+    // NOTE(unsafe): TARGET_BUFFER must also be initialised to prevent undefined
+    // behaviour (taking a mutable reference to uninitialised memory)
+
     // Setup DMA
     let streams = StreamsTuple::new(dp.MDMA, ccdr.peripheral.MDMA);