From 3f74c557edf3880d0cb7b4b4c2168a05ff8129f2 Mon Sep 17 00:00:00 2001
From: Folkert <folkert@folkertdev.nl>
Date: Sat, 5 Jun 2021 11:34:50 +0200
Subject: [PATCH] skip 'in ram' check for mutable slice in fullduplex

---
 embassy-nrf/src/spim.rs | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/embassy-nrf/src/spim.rs b/embassy-nrf/src/spim.rs
index 0ca18d88c..b5e9afbc1 100644
--- a/embassy-nrf/src/spim.rs
+++ b/embassy-nrf/src/spim.rs
@@ -196,8 +196,9 @@ impl<'d, T: Instance> FullDuplex<u8> for Spim<'d, T> {
 
     fn read_write<'a>(&'a mut self, rx: &'a mut [u8], tx: &'a [u8]) -> Self::WriteReadFuture<'a> {
         async move {
-            slice_in_ram_or(rx, Error::DMABufferNotInDataMemory)?;
             slice_in_ram_or(tx, Error::DMABufferNotInDataMemory)?;
+            // NOTE: RAM slice check for rx is not necessary, as a mutable
+            // slice can only be built from data located in RAM.
 
             // Conservative compiler fence to prevent optimizations that do not
             // take in to account actions by DMA. The fence has been placed here,