net: dsa: tag_sja1105: stop asking the sja1105 driver in sja1105_xmit_tpid

Introduced in commit 38b5beeae7a4 ("net: dsa: sja1105: prepare tagger
for handling DSA tags and VLAN simultaneously"), the sja1105_xmit_tpid
function solved quite a different problem than our needs are now.

Then, we used best-effort VLAN filtering and we were using the xmit_tpid
to tunnel packets coming from an 8021q upper through the TX VLAN allocated
by tag_8021q to that egress port. The need for a different VLAN protocol
depending on switch revision came from the fact that this in itself was
more of a hack to trick the hardware into accepting tunneled VLANs in
the first place.

Right now, we deny 8021q uppers (see sja1105_prechangeupper). Even if we
supported them again, we would not do that using the same method of
{tunneling the VLAN on egress, retagging the VLAN on ingress} that we
had in the best-effort VLAN filtering mode. It seems rather simpler that
we just allocate a VLAN in the VLAN table that is simply not used by the
bridge at all, or by any other port.

Anyway, I have 2 gripes with the current sja1105_xmit_tpid:

1. When sending packets on behalf of a VLAN-aware bridge (with the new
   TX forwarding offload framework) plus untagged (with the tag_8021q
   VLAN added by the tagger) packets, we can see that on SJA1105P/Q/R/S
   and later (which have a qinq_tpid of ETH_P_8021AD), some packets sent
   through the DSA master have a VLAN protocol of 0x8100 and others of
   0x88a8. This is strange and there is no reason for it now. If we have
   a bridge and are therefore forced to send using that bridge's TPID,
   we can as well blend with that bridge's VLAN protocol for all packets.

2. The sja1105_xmit_tpid introduces a dependency on the sja1105 driver,
   because it looks inside dp->priv. It is desirable to keep as much
   separation between taggers and switch drivers as possible. Now it
   doesn't do that anymore.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 0 insertions, 10 deletions

diff --git a/drivers/net/dsa/sja1105/sja1105_main.c b/drivers/net/dsa/sja1105/sja1105_main.c
index 976f06462223..2f8cc6686c38 100644
--- a/drivers/net/dsa/sja1105/sja1105_main.c
+++ b/drivers/net/dsa/sja1105/sja1105_main.c
@@ -2295,15 +2295,6 @@ int sja1105_vlan_filtering(struct dsa_switch *ds, int port, bool enabled,
 		tpid2 = ETH_P_SJA1105;
 	}
 
-	for (port = 0; port < ds->num_ports; port++) {
-		struct sja1105_port *sp = &priv->ports[port];
-
-		if (enabled)
-			sp->xmit_tpid = priv->info->qinq_tpid;
-		else
-			sp->xmit_tpid = ETH_P_SJA1105;
-	}
-
 	if (priv->vlan_aware == enabled)
 		return 0;
 
@@ -2988,7 +2979,6 @@ static int sja1105_setup_ports(struct sja1105_private *priv)
 		}
 		sp->xmit_worker = worker;
 		skb_queue_head_init(&sp->xmit_queue);
-		sp->xmit_tpid = ETH_P_SJA1105;
 	}
 
 	return 0;