diff --git a/drivers/pci/controller/pcie-rockchip-ep.c b/drivers/pci/controller/pcie-rockchip-ep.c
index 5fb9ce6e536e..d1a200b93b2b 100644
--- a/drivers/pci/controller/pcie-rockchip-ep.c
+++ b/drivers/pci/controller/pcie-rockchip-ep.c
@@ -264,8 +264,7 @@ static int rockchip_pcie_ep_map_addr(struct pci_epc *epc, u8 fn, u8 vfn,
 	struct rockchip_pcie *pcie = &ep->rockchip;
 	u32 r;
 
-	r = find_first_zero_bit(&ep->ob_region_map,
-				sizeof(ep->ob_region_map) * BITS_PER_LONG);
+	r = find_first_zero_bit(&ep->ob_region_map, BITS_PER_LONG);
 	/*
 	 * Region 0 is reserved for configuration space and shouldn't
 	 * be used elsewhere per TRM, so leave it out.