ospi: properly respect the max DMA transfer size when reading

1 files changed, 20 insertions, 16 deletions

diff --git a/embassy-stm32/src/ospi/mod.rs b/embassy-stm32/src/ospi/mod.rs
index 2e4943a1b..dbcf07469 100644
--- a/embassy-stm32/src/ospi/mod.rs
+++ b/embassy-stm32/src/ospi/mod.rs
@@ -1171,16 +1171,18 @@ impl<'d, T: Instance> Ospi<'d, T, Async> {
             T::REGS.ar().write(|v| v.set_address(current_address));
         }
 
-        let transfer = unsafe {
-            self.dma
-                .as_mut()
-                .unwrap()
-                .read(T::REGS.dr().as_ptr() as *mut W, buf, Default::default())
-        };
+        for chunk in buf.chunks_mut(0xFFFF / W::size().bytes()) {
+            let transfer = unsafe {
+                self.dma
+                    .as_mut()
+                    .unwrap()
+                    .read(T::REGS.dr().as_ptr() as *mut W, chunk, Default::default())
+            };
 
-        T::REGS.cr().modify(|w| w.set_dmaen(true));
+            T::REGS.cr().modify(|w| w.set_dmaen(true));
 
-        transfer.blocking_wait();
+            transfer.blocking_wait();
+        }
 
         finish_dma(T::REGS);
 
@@ -1246,16 +1248,18 @@ impl<'d, T: Instance> Ospi<'d, T, Async> {
             T::REGS.ar().write(|v| v.set_address(current_address));
         }
 
-        let transfer = unsafe {
-            self.dma
-                .as_mut()
-                .unwrap()
-                .read(T::REGS.dr().as_ptr() as *mut W, buf, Default::default())
-        };
+        for chunk in buf.chunks_mut(0xFFFF / W::size().bytes()) {
+            let transfer = unsafe {
+                self.dma
+                    .as_mut()
+                    .unwrap()
+                    .read(T::REGS.dr().as_ptr() as *mut W, chunk, Default::default())
+            };
 
-        T::REGS.cr().modify(|w| w.set_dmaen(true));
+            T::REGS.cr().modify(|w| w.set_dmaen(true));
 
-        transfer.await;
+            transfer.await;
+        }
 
         finish_dma(T::REGS);