We poll nexthops in HW and call for each active nexthop appropriate
neighbour.

Also we provide implicity neighbour resolving.
For example, user have added nexthop route:
  # ip route add 5.5.5.5 via 1.1.1.2
But neighbour 1.1.1.2 doesn't exist. In this case we will try to call
neigh_event_send, even if there is no traffic.
This is useful, when you have add route, which will be used after some
time but with a lot of traffic (burst). So, we has prepared, offloaded
route in advance.

Co-developed-by: Taras Chornyi <tchornyi@marvell.com>
Signed-off-by: Taras Chornyi <tchornyi@marvell.com>
Co-developed-by: Oleksandr Mazur <oleksandr.mazur@plvision.eu>
Signed-off-by: Oleksandr Mazur <oleksandr.mazur@plvision.eu>
Signed-off-by: Yevhen Orlov <yevhen.orlov@plvision.eu>
---
 .../net/ethernet/marvell/prestera/prestera.h  |   3 +
 .../marvell/prestera/prestera_router.c        | 111 ++++++++++++++++++
 2 files changed, 114 insertions(+)

diff --git a/drivers/net/ethernet/marvell/prestera/prestera.h b/drivers/net/ethernet/marvell/prestera/prestera.h
index 540a36069b79..35554ee805cd 100644
--- a/drivers/net/ethernet/marvell/prestera/prestera.h
+++ b/drivers/net/ethernet/marvell/prestera/prestera.h
@@ -324,6 +324,9 @@ struct prestera_router {
 	struct notifier_block netevent_nb;
 	u8 *nhgrp_hw_state_cache; /* Bitmap cached hw state of nhs */
 	unsigned long nhgrp_hw_cache_kick; /* jiffies */
+	struct {
+		struct delayed_work dw;
+	} neighs_update;
 };
 
 struct prestera_rxtx_params {
diff --git a/drivers/net/ethernet/marvell/prestera/prestera_router.c b/drivers/net/ethernet/marvell/prestera/prestera_router.c
index af7d24390d2e..4046be0e86ff 100644
--- a/drivers/net/ethernet/marvell/prestera/prestera_router.c
+++ b/drivers/net/ethernet/marvell/prestera/prestera_router.c
@@ -16,6 +16,9 @@
 #include "prestera.h"
 #include "prestera_router_hw.h"
 
+#define PRESTERA_IMPLICITY_RESOLVE_DEAD_NEIGH
+#define PRESTERA_NH_PROBE_INTERVAL 5000 /* ms */
+
 struct prestera_kern_neigh_cache_key {
 	struct prestera_ip_addr addr;
 	struct net_device *dev;
@@ -32,6 +35,7 @@ struct prestera_kern_neigh_cache {
 	/* Lock cache if neigh is present in kernel */
 	bool in_kernel;
 };
+
 struct prestera_kern_fib_cache_key {
 	struct prestera_ip_addr addr;
 	u32 prefix_len;
@@ -1021,6 +1025,78 @@ __prestera_k_arb_util_fib_overlapped(struct prestera_switch *sw,
 	return rfc;
 }
 
+static void __prestera_k_arb_hw_state_upd(struct prestera_switch *sw,
+					  struct prestera_kern_neigh_cache *nc)
+{
+	struct prestera_nh_neigh_key nh_key;
+	struct prestera_nh_neigh *nh_neigh;
+	struct neighbour *n;
+	bool hw_active;
+
+	prestera_util_nc_key2nh_key(&nc->key, &nh_key);
+	nh_neigh = prestera_nh_neigh_find(sw, &nh_key);
+	if (!nh_neigh) {
+		pr_err("Cannot find nh_neigh for cached %pI4n",
+		       &nc->key.addr.u.ipv4);
+		return;
+	}
+
+	hw_active = prestera_nh_neigh_util_hw_state(sw, nh_neigh);
+
+#ifdef PRESTERA_IMPLICITY_RESOLVE_DEAD_NEIGH
+	if (!hw_active && nc->in_kernel)
+		goto out;
+#else /* PRESTERA_IMPLICITY_RESOLVE_DEAD_NEIGH */
+	if (!hw_active)
+		goto out;
+#endif /* PRESTERA_IMPLICITY_RESOLVE_DEAD_NEIGH */
+
+	if (nc->key.addr.v == PRESTERA_IPV4) {
+		n = neigh_lookup(&arp_tbl, &nc->key.addr.u.ipv4,
+				 nc->key.dev);
+		if (!n)
+			n = neigh_create(&arp_tbl, &nc->key.addr.u.ipv4,
+					 nc->key.dev);
+	} else {
+		n = NULL;
+	}
+
+	if (!IS_ERR(n) && n) {
+		neigh_event_send(n, NULL);
+		neigh_release(n);
+	} else {
+		pr_err("Cannot create neighbour %pI4n", &nc->key.addr.u.ipv4);
+	}
+
+out:
+	return;
+}
+
+/* Propagate hw state to kernel */
+static void prestera_k_arb_hw_evt(struct prestera_switch *sw)
+{
+	struct prestera_kern_neigh_cache *n_cache;
+	struct rhashtable_iter iter;
+
+	rhashtable_walk_enter(&sw->router->kern_neigh_cache_ht, &iter);
+	rhashtable_walk_start(&iter);
+	while (1) {
+		n_cache = rhashtable_walk_next(&iter);
+
+		if (!n_cache)
+			break;
+
+		if (IS_ERR(n_cache))
+			continue;
+
+		rhashtable_walk_stop(&iter);
+		__prestera_k_arb_hw_state_upd(sw, n_cache);
+		rhashtable_walk_start(&iter);
+	}
+	rhashtable_walk_stop(&iter);
+	rhashtable_walk_exit(&iter);
+}
+
 /* Propagate kernel event to hw */
 static void prestera_k_arb_n_evt(struct prestera_switch *sw,
 				 struct neighbour *n)
@@ -1441,6 +1517,34 @@ static int prestera_router_netevent_event(struct notifier_block *nb,
 	return NOTIFY_DONE;
 }
 
+static void prestera_router_update_neighs_work(struct work_struct *work)
+{
+	struct prestera_router *router;
+
+	router = container_of(work, struct prestera_router,
+			      neighs_update.dw.work);
+	rtnl_lock();
+
+	prestera_k_arb_hw_evt(router->sw);
+
+	rtnl_unlock();
+	prestera_queue_delayed_work(&router->neighs_update.dw,
+				    msecs_to_jiffies(PRESTERA_NH_PROBE_INTERVAL));
+}
+
+static int prestera_neigh_work_init(struct prestera_switch *sw)
+{
+	INIT_DELAYED_WORK(&sw->router->neighs_update.dw,
+			  prestera_router_update_neighs_work);
+	prestera_queue_delayed_work(&sw->router->neighs_update.dw, 0);
+	return 0;
+}
+
+static void prestera_neigh_work_fini(struct prestera_switch *sw)
+{
+	cancel_delayed_work_sync(&sw->router->neighs_update.dw);
+}
+
 int prestera_router_init(struct prestera_switch *sw)
 {
 	struct prestera_router *router;
@@ -1474,6 +1578,10 @@ int prestera_router_init(struct prestera_switch *sw)
 		goto err_nh_state_cache_alloc;
 	}
 
+	err = prestera_neigh_work_init(sw);
+	if (err)
+		goto err_neigh_work_init;
+
 	router->inetaddr_valid_nb.notifier_call = __prestera_inetaddr_valid_cb;
 	err = register_inetaddr_validator_notifier(&router->inetaddr_valid_nb);
 	if (err)
@@ -1504,6 +1612,8 @@ int prestera_router_init(struct prestera_switch *sw)
 err_register_inetaddr_notifier:
 	unregister_inetaddr_validator_notifier(&router->inetaddr_valid_nb);
 err_register_inetaddr_validator_notifier:
+	prestera_neigh_work_fini(sw);
+err_neigh_work_init:
 	kfree(router->nhgrp_hw_state_cache);
 err_nh_state_cache_alloc:
 	rhashtable_destroy(&router->kern_neigh_cache_ht);
@@ -1522,6 +1632,7 @@ void prestera_router_fini(struct prestera_switch *sw)
 	unregister_netevent_notifier(&sw->router->netevent_nb);
 	unregister_inetaddr_notifier(&sw->router->inetaddr_nb);
 	unregister_inetaddr_validator_notifier(&sw->router->inetaddr_valid_nb);
+	prestera_neigh_work_fini(sw);
 	prestera_queue_drain();
 
 	prestera_k_arb_abort(sw);
-- 
2.17.1