diff --git a/libraries/AP_HAL_ChibiOS/hwdef/common/bouncebuffer.c b/libraries/AP_HAL_ChibiOS/hwdef/common/bouncebuffer.c
new file mode 100644
index 0000000000..d50b637ea4
--- /dev/null
+++ b/libraries/AP_HAL_ChibiOS/hwdef/common/bouncebuffer.c
@@ -0,0 +1,110 @@
+/*
+ * This file is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This file is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ * See the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+/*
+  bouncebuffer code for DMA safe memory operations
+ */
+#include "stm32_util.h"
+#include <stdint.h>
+#include <string.h>
+#include <stdio.h>
+#include "bouncebuffer.h"
+
+#if defined(STM32F7) && STM32_DMA_CACHE_HANDLING == TRUE
+// on F7 we check we are in the DTCM region, and 16 bit aligned
+#define IS_DMA_SAFE(addr) ((((uint32_t)(addr)) & 0xFFFE0001) == 0x20000000)
+#else
+// this checks an address is in main memory and 16 bit aligned
+#define IS_DMA_SAFE(addr) ((((uint32_t)(addr)) & 0xF0000001) == 0x20000000)
+#endif
+
+/*
+  initialise a bouncebuffer
+ */
+void bouncebuffer_init(struct bouncebuffer_t **bouncebuffer)
+{
+    (*bouncebuffer) = calloc(1, sizeof(struct bouncebuffer_t));
+    osalDbgAssert(((*bouncebuffer) != NULL), "bouncebuffer init");
+}
+
+/*
+  setup for reading from a device into memory, allocating a bouncebuffer if needed
+ */
+void bouncebuffer_setup_read(struct bouncebuffer_t *bouncebuffer, uint8_t **buf, uint32_t size)
+{
+    if (IS_DMA_SAFE(*buf)) {
+        // nothing needs to be done
+        return;
+    }
+    osalDbgAssert((bouncebuffer->busy == false), "bouncebuffer read");        
+    bouncebuffer->orig_buf = *buf;
+    if (bouncebuffer->size < size) {
+        if (bouncebuffer->size > 0) {
+            free(bouncebuffer->dma_buf);
+        }
+        bouncebuffer->dma_buf = malloc_dma(size);
+        osalDbgAssert((bouncebuffer->dma_buf != NULL), "bouncebuffer read allocate");
+        bouncebuffer->size = size;
+    }
+    *buf = bouncebuffer->dma_buf;
+    bouncebuffer->busy = true;
+}
+
+/*
+  finish a read operation
+ */
+void bouncebuffer_finish_read(struct bouncebuffer_t *bouncebuffer, const uint8_t *buf, uint32_t size)
+{
+    if (buf == bouncebuffer->dma_buf) {
+        osalDbgAssert((bouncebuffer->busy == true), "bouncebuffer finish_read");        
+        memcpy(bouncebuffer->orig_buf, buf, size);
+        bouncebuffer->busy = false;
+    }
+}
+
+
+/*
+  setup for reading from memory to a device, allocating a bouncebuffer if needed
+ */
+void bouncebuffer_setup_write(struct bouncebuffer_t *bouncebuffer, const uint8_t **buf, uint32_t size)
+{
+    if (IS_DMA_SAFE(*buf)) {
+        // nothing needs to be done
+        return;
+    }
+    osalDbgAssert((bouncebuffer->busy == false), "bouncebuffer write");        
+    if (bouncebuffer->size < size) {
+        if (bouncebuffer->size > 0) {
+            free(bouncebuffer->dma_buf);
+        }
+        bouncebuffer->dma_buf = malloc_dma(size);
+        osalDbgAssert((bouncebuffer->dma_buf != NULL), "bouncebuffer write allocate");
+        bouncebuffer->size = size;
+    }
+    memcpy(bouncebuffer->dma_buf, *buf, size);
+    *buf = bouncebuffer->dma_buf;
+    bouncebuffer->busy = true;
+}
+
+
+/*
+  finish a write operation
+ */
+void bouncebuffer_finish_write(struct bouncebuffer_t *bouncebuffer, const uint8_t *buf)
+{
+    if (buf == bouncebuffer->dma_buf) {
+        osalDbgAssert((bouncebuffer->busy == true), "bouncebuffer finish_wite");        
+        bouncebuffer->busy = false;
+    }
+}
diff --git a/libraries/AP_HAL_ChibiOS/hwdef/common/bouncebuffer.h b/libraries/AP_HAL_ChibiOS/hwdef/common/bouncebuffer.h
new file mode 100644
index 0000000000..a3704884a6
--- /dev/null
+++ b/libraries/AP_HAL_ChibiOS/hwdef/common/bouncebuffer.h
@@ -0,0 +1,48 @@
+/*
+  bouncebuffer code for supporting ChibiOS drivers that use DMA, but may be passed memory that
+  is not DMA safe. 
+
+  This API assumes that there will be only one user of a bouncebuffer at a time
+ */
+
+#pragma once
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+struct bouncebuffer_t {
+    uint8_t *dma_buf;
+    uint8_t *orig_buf;
+    uint32_t size;
+    bool busy;
+};
+
+/*
+  initialise a bouncebuffer
+ */
+void bouncebuffer_init(struct bouncebuffer_t **bouncebuffer);
+
+/*
+  setup for reading from a device into memory, allocating a bouncebuffer if needed
+ */
+void bouncebuffer_setup_read(struct bouncebuffer_t *bouncebuffer, uint8_t **buf, uint32_t size);
+    
+/*
+  finish a read operation
+ */
+void bouncebuffer_finish_read(struct bouncebuffer_t *bouncebuffer, const uint8_t *buf, uint32_t size);
+    
+/*
+  setup for reading from memory to a device, allocating a bouncebuffer if needed
+ */
+void bouncebuffer_setup_write(struct bouncebuffer_t *bouncebuffer, const uint8_t **buf, uint32_t size);
+    
+/*
+  finish a write operation
+ */
+void bouncebuffer_finish_write(struct bouncebuffer_t *bouncebuffer, const uint8_t *buf);
+
+#ifdef __cplusplus
+}
+#endif