diff --git a/drivers/usb/host/ohci-ppc-of.c b/drivers/usb/host/ohci-ppc-of.c
index 1ca1821..0c12f4e 100644
--- a/drivers/usb/host/ohci-ppc-of.c
+++ b/drivers/usb/host/ohci-ppc-of.c
@@ -110,7 +110,7 @@
 		return -ENOMEM;
 
 	hcd->rsrc_start = res.start;
-	hcd->rsrc_len = res.end - res.start + 1;
+	hcd->rsrc_len = resource_size(&res);
 
 	if (!request_mem_region(hcd->rsrc_start, hcd->rsrc_len, hcd_name)) {
 		printk(KERN_ERR "%s: request_mem_region failed\n", __FILE__);