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Diffstat (limited to 'Documentation/networking/dsa/sja1105.rst')
| -rw-r--r-- | Documentation/networking/dsa/sja1105.rst | 33 |
1 files changed, 30 insertions, 3 deletions
diff --git a/Documentation/networking/dsa/sja1105.rst b/Documentation/networking/dsa/sja1105.rst index 29b1bae0cf00..8ab60eef07d4 100644 --- a/Documentation/networking/dsa/sja1105.rst +++ b/Documentation/networking/dsa/sja1105.rst @@ -79,7 +79,7 @@ The hardware tags all traffic internally with a port-based VLAN (pvid), or it decodes the VLAN information from the 802.1Q tag. Advanced VLAN classification is not possible. Once attributed a VLAN tag, frames are checked against the port's membership rules and dropped at ingress if they don't match any VLAN. -This behavior is available when switch ports are enslaved to a bridge with +This behavior is available when switch ports join a bridge with ``vlan_filtering 1``. Normally the hardware is not configurable with respect to VLAN awareness, but @@ -122,7 +122,7 @@ on egress. Using ``vlan_filtering=1``, the behavior is the other way around: offloaded flows can be steered to TX queues based on the VLAN PCP, but the DSA net devices are no longer able to do that. To inject frames into a hardware TX queue with VLAN awareness active, it is necessary to create a VLAN -sub-interface on the DSA master port, and send normal (0x8100) VLAN-tagged +sub-interface on the DSA conduit port, and send normal (0x8100) VLAN-tagged towards the switch, with the VLAN PCP bits set appropriately. Management traffic (having DMAC 01-80-C2-xx-xx-xx or 01-19-1B-xx-xx-xx) is the @@ -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 ===================================== @@ -362,7 +389,7 @@ MDIO bus and PHY management The SJA1105 does not have an MDIO bus and does not perform in-band AN either. Therefore there is no link state notification coming from the switch device. A board would need to hook up the PHYs connected to the switch to any other -MDIO bus available to Linux within the system (e.g. to the DSA master's MDIO +MDIO bus available to Linux within the system (e.g. to the DSA conduit's MDIO bus). Link state management then works by the driver manually keeping in sync (over SPI commands) the MAC link speed with the settings negotiated by the PHY. |