[RFC PATCH net-next 4/4] net: ethernet: ti: cpsw: fix vlan configuration while down/up

[Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>]

The vlan configuration is not restored after interface donw/up sequence
(if dual-emac - both interfaces). Tested on am572x EVM.

Steps to check:
~# ip link add link eth1 name eth1.100 type vlan id 100
~# ifconfig eth0 down
~# ifconfig eth1 down

This is TI sdk tool, dumping all ALE entries, see they are present
~# switch-config -d
~# ifconfig eth1 up
See entry for vid 100 is absent
~# switch-config -d

Try to remove vid and observe warning:
~# ip link del eth1.100
[  739.526757] net eth1: removing vlanid 100 from vlan filter
[  739.533322] failed to kill vid 0081/100 for device eth1

This patch fixes it, restoring only vlan ALE entries and all other
unicast/multicast entries are restored by system calling rx_mode ndo.

Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>
---
 drivers/net/ethernet/ti/cpsw.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/drivers/net/ethernet/ti/cpsw.c b/drivers/net/ethernet/ti/cpsw.c
index 5967484619d4..0b28a90b62bb 100644
--- a/drivers/net/ethernet/ti/cpsw.c
+++ b/drivers/net/ethernet/ti/cpsw.c
@@ -565,6 +565,9 @@ static const struct cpsw_stats cpsw_gstrings_ch_stats[] = {
 				(func)(slave++, ##arg);			\
 	} while (0)
 
+static int cpsw_ndo_vlan_rx_add_vid(struct net_device *ndev,
+				    __be16 proto, u16 vid);
+
 static inline int cpsw_get_slave_port(u32 slave_num)
 {
 	return slave_num + 1;
@@ -1955,9 +1958,23 @@ static void cpsw_mqprio_resume(struct cpsw_slave *slave, struct cpsw_priv *priv)
 	slave_write(slave, tx_prio_map, tx_prio_rg);
 }
 
+static int cpsw_restore_vlans(struct net_device *vdev, int vid, void *arg)
+{
+	struct cpsw_priv *priv = arg;
+
+	if (!vdev)
+		return 0;
+
+	cpsw_ndo_vlan_rx_add_vid(priv->ndev, 0, vid);
+	return 0;
+}
+
 /* restore resources after port reset */
 static void cpsw_restore(struct cpsw_priv *priv)
 {
+	/* restore vlan configurations */
+	vlan_for_each(priv->ndev, cpsw_restore_vlans, priv);
+
 	/* restore MQPRIO offload */
 	for_each_slave(priv, cpsw_mqprio_resume, priv);
 
-- 
2.17.1