Messages in this thread | | | Date | Thu, 3 Feb 2022 14:53:33 +0200 | From | Vladimir Oltean <> | Subject | Re: [PATCH v2 net-next 4/5] net: dsa: mv88e6xxx: Improve multichip isolation of standalone ports |
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On Thu, Feb 03, 2022 at 11:16:56AM +0100, Tobias Waldekranz wrote: > Given that standalone ports are now configured to bypass the ATU and > forward all frames towards the upstream port, extend the ATU bypass to > multichip systems. > > Load VID 0 (standalone) into the VTU with the policy bit set. Since > VID 4095 (bridged) is already loaded, we now know that all VIDs in use > are always available in all VTUs. Therefore, we can safely enable > 802.1Q on DSA ports. > > Setting the DSA ports' VTU policy to TRAP means that all incoming > frames on VID 0 will be classified as MGMT - as a result, the ATU is > bypassed on all subsequent switches. > > With this isolation in place, we are able to support configurations > that are simultaneously very quirky and very useful. Quirky because it > involves looping cables between local switchports like in this > example: > > CPU > | .------. > .---0---. | .----0----. > | sw0 | | | sw1 | > '-1-2-3-' | '-1-2-3-4-' > $ @ '---' $ @ % % > > We have three physically looped pairs ($, @, and %). > > This is very useful because it allows us to run the kernel's > kselftests for the bridge on mv88e6xxx hardware. > > Signed-off-by: Tobias Waldekranz <tobias@waldekranz.com> > ---
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
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