diff --git a/drivers/net/macb.c b/drivers/net/macb.c
index 6c6a028..27125cd 100644
--- a/drivers/net/macb.c
+++ b/drivers/net/macb.c
@@ -1169,7 +1169,7 @@
 	clk_enable(bp->hclk);
 #endif
 
-	bp->regs = ioremap(regs->start, regs->end - regs->start + 1);
+	bp->regs = ioremap(regs->start, resource_size(regs));
 	if (!bp->regs) {
 		dev_err(&pdev->dev, "failed to map registers, aborting.\n");
 		err = -ENOMEM;