diff --git a/drivers/mtd/nand/excite_nandflash.c b/drivers/mtd/nand/excite_nandflash.c
index 72446fb..bd323e4 100644
--- a/drivers/mtd/nand/excite_nandflash.c
+++ b/drivers/mtd/nand/excite_nandflash.c
@@ -79,7 +79,7 @@ excite_nand_map_regs(struct platform_device *d, const char *basename)
 	    excite_nand_get_resource(d, IORESOURCE_MEM, basename);
 
 	if (r)
-		result = ioremap_nocache(r->start, r->end + 1 - r->start);
+		result = ioremap_nocache(r->start, resource_size(r));
 	return result;
 }