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Diffstat (limited to 'Documentation/networking/dsa/sja1105.rst')
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diff --git a/Documentation/networking/dsa/sja1105.rst b/Documentation/networking/dsa/sja1105.rst index 29b1bae0cf00..e0219c1452ab 100644 --- a/Documentation/networking/dsa/sja1105.rst +++ b/Documentation/networking/dsa/sja1105.rst @@ -293,6 +293,33 @@ of dropped frames, which is a sum of frames dropped due to timing violations, lack of destination ports and MTU enforcement checks). Byte-level counters are not available. +Limitations +=========== + +The SJA1105 switch family always performs VLAN processing. When configured as +VLAN-unaware, frames carry a different VLAN tag internally, depending on +whether the port is standalone or under a VLAN-unaware bridge. + +The virtual link keys are always fixed at {MAC DA, VLAN ID, VLAN PCP}, but the +driver asks for the VLAN ID and VLAN PCP when the port is under a VLAN-aware +bridge. Otherwise, it fills in the VLAN ID and PCP automatically, based on +whether the port is standalone or in a VLAN-unaware bridge, and accepts only +"VLAN-unaware" tc-flower keys (MAC DA). + +The existing tc-flower keys that are offloaded using virtual links are no +longer operational after one of the following happens: + +- port was standalone and joins a bridge (VLAN-aware or VLAN-unaware) +- port is part of a bridge whose VLAN awareness state changes +- port was part of a bridge and becomes standalone +- port was standalone, but another port joins a VLAN-aware bridge and this + changes the global VLAN awareness state of the bridge + +The driver cannot veto all these operations, and it cannot update/remove the +existing tc-flower filters either. So for proper operation, the tc-flower +filters should be installed only after the forwarding configuration of the port +has been made, and removed by user space before making any changes to it. + Device Tree bindings and board design ===================================== |