diff --git a/drivers/bus/mvebu-mbus.c b/drivers/bus/mvebu-mbus.c
index c7f396903184..70db4d5638a6 100644
--- a/drivers/bus/mvebu-mbus.c
+++ b/drivers/bus/mvebu-mbus.c
@@ -720,7 +720,7 @@ mvebu_mbus_default_setup_cpu_target(struct mvebu_mbus_state *mbus)
 			if (mbus->hw_io_coherency)
 				w->mbus_attr |= ATTR_HW_COHERENCY;
 			w->base = base & DDR_BASE_CS_LOW_MASK;
-			w->size = (size | ~DDR_SIZE_MASK) + 1;
+			w->size = (u64)(size | ~DDR_SIZE_MASK) + 1;
 		}
 	}
 	mvebu_mbus_dram_info.num_cs = cs;
diff --git a/include/linux/mbus.h b/include/linux/mbus.h
index 2931aa43dab1..f70420e65ad7 100644
--- a/include/linux/mbus.h
+++ b/include/linux/mbus.h
@@ -31,8 +31,8 @@ struct mbus_dram_target_info
 	struct mbus_dram_window {
 		u8	cs_index;
 		u8	mbus_attr;
-		u32	base;
-		u32	size;
+		u64	base;
+		u64	size;
 	} cs[4];
 };