diff --git a/drivers/pci/host/pcie-designware.c b/drivers/pci/host/pcie-designware.c
index 21716827847a..8bcaed18f0dd 100644
--- a/drivers/pci/host/pcie-designware.c
+++ b/drivers/pci/host/pcie-designware.c
@@ -517,6 +517,11 @@ int dw_pcie_host_init(struct pcie_port *pp)
 	if (pp->ops->host_init)
 		pp->ops->host_init(pp);
 
+	/*
+	 * If the platform provides ->rd_other_conf, it means the platform
+	 * uses its own address translation component rather than ATU, so
+	 * we should not program the ATU here.
+	 */
 	if (!pp->ops->rd_other_conf)
 		dw_pcie_prog_outbound_atu(pp, PCIE_ATU_REGION_INDEX1,
 					  PCIE_ATU_TYPE_MEM, pp->mem_base,