[PATCH net-next v2 8/8] net: dsa: mt7530: implement port_change_conduit op

[Daniel Golle]

On Sat, Jun 13, 2026 at 02:11:45AM +0100, Daniel Golle wrote:
> Allow changing the CPU port affinity of user ports at runtime via the
> IFLA_DSA_CONDUIT netlink attribute. This updates the port matrix to
> forward to the new CPU port instead of the old one.
> 
> Limit the operation to MT7531. There, trapped link-local frames follow
> the per-port affinity, as the MT7531_CPU_PMAP destination mask is
> further restricted by the port matrix. A conduit change is hence fully
> honoured by the hardware, for regular traffic as well as for trapped
> frames.
> 
> The MT7530 switch, including the variant embedded in the MT7621 SoC,
> instead traps frames to the single CPU port set in the CPU_PORT field
> of the MFC register, regardless of the affinity of the inbound user
> port. With user ports affine to different CPU ports there is no
> correct value for that field, so per-port CPU affinity cannot be fully
> implemented for trapped frames. Routing a WAN port via the second SoC
> GMAC is conventionally covered by the PHY muxing feature on these
> switches, which bypasses the switch fabric and does not involve a CPU
> port at all.
> 
> The switches on the MT7988, EN7581 and AN7583 SoCs only have a
> single CPU port, leaving no other conduit to change to.
> 
> Signed-off-by: Daniel Golle <daniel at makrotopia.org>

I forgot to include the previously received

Acked-by: Chester A. Unal <chester.a.unal at arinc9.com>

See also:

https://patchwork.kernel.org/comment/27003848/

https://lore.kernel.org/all/02ad5de0-ea6a-4267-8686-72e3f98fce4e@arinc9.com/