On 1/20/2021 6:36 PM, Vladimir Oltean wrote:
> From: Vladimir Oltean <vladimir.olt...@nxp.com>
>
> Context: Ocelot switches put the injection/extraction frame header in
> front of the Ethernet header. When used in NPI mode, a DSA master would
> see junk instead of the destination MAC address, and it would most
> likely drop the packets. So the Ocelot frame header can have an optional
> prefix, which is just "ff:ff:ff:ff:ff:fe > ff:ff:ff:ff:ff:ff" padding
> put before the actual tag (still before the real Ethernet header) such
> that the DSA master thinks it's looking at a broadcast frame with a
> strange EtherType.
>
> Unfortunately, a lesson learned in commit 69df578c5f4b ("net: mscc:
> ocelot: eliminate confusion between CPU and NPI port") seems to have
> been forgotten in the meanwhile.
>
> The CPU port module and the NPI port have independent settings for the
> length of the tag prefix. However, the driver is using the same variable
> to program both of them.
>
> There is no reason really to use any tag prefix with the CPU port
> module, since that is not connected to any Ethernet port. So this patch
> makes the inj_prefix and xtr_prefix variables apply only to the NPI
> port (which the switchdev ocelot_vsc7514 driver does not use).
>
> Signed-off-by: Vladimir Oltean <vladimir.olt...@nxp.com>
Reviewed-by: Florian Fainelli <f.faine...@gmail.com>
--
Florian
