Re: [PATCH net v3 3/3] net: dsa: mv88e6xxx: don't clip ATU Move ToPort delete sentinel

[Andrew Lunn]

On Wed, Jul 15, 2026 at 09:29:43AM +1000, Luke Howard wrote:
> mv88e6xxx_g1_atu_data_write() masked the port vector, which is correct
> for a load operation (where portvec is a bitmap) but wrong for a move,
> where the portvec encodes a ToPort/FromPort pair.
> 
> An all-ones ToPort value is the sentinel used to delete an entry. Chips
> with fewer than eight ports (e.g. 88E6141) clipped this value, turning a
> delete into a move (to port 3 on the 6141/6341). Other chips such as
> the 7-port 88E6352 were unaffected by chance.
> 
> Fix this by moving the mv88e6xxx_port_mask() mask into
> mv88e6xxx_g1_atu_loadpurge(), where the portvec always represents a
> bitmap; the move path then writes its ToPort/FromPort pair unmasked.
> 
> Fixes: e606ca36bbf2 ("net: dsa: mv88e6xxx: rework ATU Remove")
> Assisted-by: Claude:claude-opus-4-8
> Signed-off-by: Luke Howard <lukeh@xxxxxxxx>

Reviewed-by: Andrew Lunn <andrew@xxxxxxx>

    Andrew