docs: net: dsa: sja1105: document the best_effort_vlan_filtering option

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 27 insertions, 0 deletions

diff --git a/Documentation/networking/devlink-params-sja1105.txt b/Documentation/networking/devlink-params-sja1105.txt
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+best_effort_vlan_filtering
+			[DEVICE, DRIVER-SPECIFIC]
+			Allow plain ETH_P_8021Q headers to be used as DSA tags.
+			Benefits:
+			- Can terminate untagged traffic over switch net
+			  devices even when enslaved to a bridge with
+			  vlan_filtering=1.
+			- Can terminate VLAN-tagged traffic over switch net
+			  devices even when enslaved to a bridge with
+			  vlan_filtering=1, with some constraints (no more than
+			  7 non-pvid VLANs per user port).
+			- Can do QoS based on VLAN PCP and VLAN membership
+			  admission control for autonomously forwarded frames
+			  (regardless of whether they can be terminated on the
+			  CPU or not).
+			Drawbacks:
+			- User cannot use VLANs in range 1024-3071. If the
+			  switch receives frames with such VIDs, it will
+			  misinterpret them as DSA tags.
+			- Switch uses Shared VLAN Learning (FDB lookup uses
+			  only DMAC as key).
+			- When VLANs span cross-chip topologies, the total
+			  number of permitted VLANs may be less than 7 per
+			  port, due to a maximum number of 32 VLAN retagging
+			  rules per switch.
+			Configuration mode: runtime
+			Type: bool.