Messages in this thread | | | Date | Thu, 30 May 2019 07:23:56 -0700 | From | Richard Cochran <> | Subject | Re: [PATCH net-next 3/5] net: dsa: mv88e6xxx: Let taggers specify a can_timestamp function |
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On Thu, May 30, 2019 at 10:42:41AM +0300, Vladimir Oltean wrote: > The meta frames generated by the SJA1105 do not contain any seqid.
So this cannot ever work...
> They contain: > * A globally programmable DMAC > * A globally programmable SMAC
Don't know what these are, but doesn't sound like they uniquely identify the original frame.
> * The 0x8 EtherType > * A partial (24-bit or 32-bit) RX timestamp > * Two bytes from the initial (pre follow-up) frame's DMAC, before the > switch mangled those with the source port and switch id. The driver is > supposed to patch these bytes from the follow-up back into the initial > frame before passing them up the stack. > * The source port that generated the meta frame > * The switch id that generated the meta frame
None of these match to the original frame uniquely. Looks like this is a dead end.
I recommend forgetting about these meta frames. Instead, read out the time stamps over MDIO.
Thanks, Richard
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