diff --git a/drivers/coresight/coresight-stm.c b/drivers/coresight/coresight-stm.c
index 085f7211669..81672ea576f 100644
--- a/drivers/coresight/coresight-stm.c
+++ b/drivers/coresight/coresight-stm.c
@@ -450,6 +450,8 @@ static int stm_trace_ost_tail_64bit(unsigned long ch_addr, uint32_t options)
 
 static int stm_send(void *addr, const void *data, uint32_t size)
 {
+	uint32_t len = size;
+
 	if (((unsigned long)data & 0x1) && (size >= 1)) {
 		stm_data_writeb(*(uint8_t *)data, addr);
 		data++;
@@ -479,7 +481,7 @@ static int stm_send(void *addr, const void *data, uint32_t size)
 		size--;
 	}
 
-	return size;
+	return len;
 }
 
 static int stm_trace_ost_header(unsigned long ch_addr, uint32_t options,