diff --git a/drivers/mmc/host/au1xmmc.c b/drivers/mmc/host/au1xmmc.c
index c8da5d30a861b5b7a294945f59aae0d80968c128..e14b866b270f5ba89f2c9ad63c723b54f8cb25fa 100644
--- a/drivers/mmc/host/au1xmmc.c
+++ b/drivers/mmc/host/au1xmmc.c
@@ -964,7 +964,7 @@ static int __devinit au1xmmc_probe(struct platform_device *pdev)
 		goto out1;
 	}
 
-	host->ioarea = request_mem_region(r->start, r->end - r->start + 1,
+	host->ioarea = request_mem_region(r->start, resource_size(r),
 					   pdev->name);
 	if (!host->ioarea) {
 		dev_err(&pdev->dev, "mmio already in use\n");