From 8a75b9d4c9d32c88b487bd98bf8019f029215165 Mon Sep 17 00:00:00 2001
From: Marek Vasut <marex@denx.de>
Date: Sat, 15 Dec 2018 01:58:06 +0100
Subject: [PATCH] net: dsa: ksz: Add STP multicast handling

In case the destination address is link local, add override bit into the
switch tag to let such a packet through the switch even if the port is
blocked.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Tristram Ha <Tristram.Ha@microchip.com>
Cc: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Cc: Woojung Huh <woojung.huh@microchip.com>
Cc: David S. Miller <davem@davemloft.net>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
 net/dsa/tag_ksz.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/net/dsa/tag_ksz.c b/net/dsa/tag_ksz.c
index c98b53f691bd..da71b9e2af52 100644
--- a/net/dsa/tag_ksz.c
+++ b/net/dsa/tag_ksz.c
@@ -110,6 +110,10 @@ static struct sk_buff *ksz9477_xmit(struct sk_buff *skb,
 	addr = skb_mac_header(nskb);
 
 	*tag = BIT(dp->index);
+
+	if (is_link_local_ether_addr(addr))
+		*tag |= KSZ9477_TAIL_TAG_OVERRIDE;
+
 	*tag = cpu_to_be16(*tag);
 
 	return nskb;