diff --git a/drivers/rapidio/rio-scan.c b/drivers/rapidio/rio-scan.c
index 7bdc674..4c15dbf 100644
--- a/drivers/rapidio/rio-scan.c
+++ b/drivers/rapidio/rio-scan.c
@@ -1134,19 +1134,30 @@
 /**
  * rio_enum_mport- Start enumeration through a master port
  * @mport: Master port to send transactions
+ * @flags: Enumeration control flags
  *
  * Starts the enumeration process. If somebody has enumerated our
  * master port device, then give up. If not and we have an active
  * link, then start recursive peer enumeration. Returns %0 if
  * enumeration succeeds or %-EBUSY if enumeration fails.
  */
-int rio_enum_mport(struct rio_mport *mport)
+int rio_enum_mport(struct rio_mport *mport, u32 flags)
 {
 	struct rio_net *net = NULL;
 	int rc = 0;
 
 	printk(KERN_INFO "RIO: enumerate master port %d, %s\n", mport->id,
 	       mport->name);
+
+	/*
+	 * To avoid multiple start requests (repeat enumeration is not supported
+	 * by this method) check if enumeration/discovery was performed for this
+	 * mport: if mport was added into the list of mports for a net exit
+	 * with error.
+	 */
+	if (mport->nnode.next || mport->nnode.prev)
+		return -EBUSY;
+
 	/* If somebody else enumerated our master port device, bail. */
 	if (rio_enum_host(mport) < 0) {
 		printk(KERN_INFO
@@ -1236,14 +1247,16 @@
 /**
  * rio_disc_mport- Start discovery through a master port
  * @mport: Master port to send transactions
+ * @flags: discovery control flags
  *
  * Starts the discovery process. If we have an active link,
- * then wait for the signal that enumeration is complete.
+ * then wait for the signal that enumeration is complete (if wait
+ * is allowed).
  * When enumeration completion is signaled, start recursive
  * peer discovery. Returns %0 if discovery succeeds or %-EBUSY
  * on failure.
  */
-int rio_disc_mport(struct rio_mport *mport)
+int rio_disc_mport(struct rio_mport *mport, u32 flags)
 {
 	struct rio_net *net = NULL;
 	unsigned long to_end;
@@ -1253,6 +1266,11 @@
 
 	/* If master port has an active link, allocate net and discover peers */
 	if (rio_mport_is_active(mport)) {
+		if (rio_enum_complete(mport))
+			goto enum_done;
+		else if (flags & RIO_SCAN_ENUM_NO_WAIT)
+			return -EAGAIN;
+
 		pr_debug("RIO: wait for enumeration to complete...\n");
 
 		to_end = jiffies + CONFIG_RAPIDIO_DISC_TIMEOUT * HZ;