diff --git a/drivers/base/dma-contiguous.c b/drivers/base/dma-contiguous.c
index 950fff9..426ba27 100644
--- a/drivers/base/dma-contiguous.c
+++ b/drivers/base/dma-contiguous.c
@@ -46,7 +46,7 @@
  * Users, who want to set the size of global CMA area for their system
  * should use cma= kernel parameter.
  */
-static const phys_addr_t size_bytes = CMA_SIZE_MBYTES * SZ_1M;
+static const phys_addr_t size_bytes = (phys_addr_t)CMA_SIZE_MBYTES * SZ_1M;
 static phys_addr_t size_cmdline = -1;
 static phys_addr_t base_cmdline;
 static phys_addr_t limit_cmdline;