On 3/23/2019 8:23 PM, Vladimir Oltean wrote:

VLAN filtering cannot be properly disabled in SJA1105. So in order to
emulate the "no VLAN awareness" behavior (not dropping traffic that is
tagged with a VID that isn't configured on the port), we need to hack
another switch feature: programmable TPID (which is 0x8100 for 802.1Q).
We are reprogramming the TPID to a bogus value (ETH_P_EDSA) which leaves
the switch thinking that all traffic is untagged, and therefore accepts
it.

Under a vlan_filtering bridge, the proper TPID of ETH_P_8021Q is
installed again, and the switch starts identifying 802.1Q-tagged
traffic.

Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
---

[snip]

+	for (i = 0; i < SJA1105_NUM_PORTS; i++) {
+		struct net_device *bridge_dev;
+
+		bridge_dev = dsa_to_port(ds, i)->bridge_dev;
+		if (bridge_dev &&
+		    bridge_dev != dsa_to_port(ds, port)->bridge_dev &&
+		    br_vlan_enabled(bridge_dev) != enabled) {
+			netdev_err(bridge_dev,
+				   "VLAN filtering is global to the switch!\n");
+			return -EINVAL;
+		}

We might want to move this to the DSA core at some point, I had some
patches lying around for doing that but got side tracked with adding
management support for b53/bcm_sf2. Not a big problem for now.

Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
-- 
Florian