diff --git a/xen/arch/arm/pci/pci-designware.c b/xen/arch/arm/pci/pci-designware.c
index 0bd67524ac..6b85213f63 100644
--- a/xen/arch/arm/pci/pci-designware.c
+++ b/xen/arch/arm/pci/pci-designware.c
@@ -285,7 +285,7 @@ void __iomem *dw_pcie_child_map_bus(struct pci_host_bridge *bridge,
                                     bridge->child_cfg->phys_addr, busdev,
                                     bridge->child_cfg->size);
     if ( ret )
-        return 0;
+        return NULL;
 
     return bridge->child_cfg->win + where;
 }
diff --git a/xen/arch/arm/pci/pci-designware.h b/xen/arch/arm/pci/pci-designware.h
index b9deb3b138..bd93dab6f2 100644
--- a/xen/arch/arm/pci/pci-designware.h
+++ b/xen/arch/arm/pci/pci-designware.h
@@ -6,12 +6,11 @@
  * Based on xen/arch/arm/pci/pci-host-generic.c
  */
 
-#include <xen/pci.h>
-#include <xen/init.h>
-
 #ifndef __PCI_DESIGNWARE_H__
 #define __PCI_DESIGNWARE_H__
 
+#include <xen/pci.h>
+#include <xen/init.h>
 
 #define PCIE_ATU_VIEWPORT               0x900
 #define PCIE_ATU_REGION_OUTBOUND        0