From: Vladimir Oltean vladimir.oltean@nxp.com
Flooding of unregistered IP multicast has been broken (both to other switch ports and to the CPU) since the ocelot driver introduction, and up until commit 4cf35a2b627a ("net: mscc: ocelot: fix broken IP multicast flooding"), a bug fix for commit 421741ea5672 ("net: mscc: ocelot: offload bridge port flags to device") from v5.12.
The driver used to set PGID_MCIPV4 and PGID_MCIPV6 to the empty port mask (0), which made unregistered IPv4/IPv6 multicast go nowhere, and without ever modifying that port mask at runtime.
The expectation is that such packets are treated as broadcast, and flooded according to the forwarding domain (to the CPU if the port is standalone, or to the CPU and other bridged ports, if under a bridge).
Since the aforementioned commit, the limitation has been lifted by responding to SWITCHDEV_ATTR_ID_PORT_BRIDGE_FLAGS events emitted by the bridge. As for host flooding, DSA synthesizes another call to ocelot_port_bridge_flags() on the NPI port which ensures that the CPU gets the unregistered multicast traffic it might need, for example for smcroute to work between standalone ports.
But between v4.18 and v5.12, IP multicast flooding has remained unfixed.
Delete the inexplicable premature optimization of clearing PGID_MCIPV4 and PGID_MCIPV6 as part of the init sequence, and allow unregistered IP multicast to be flooded freely according to the forwarding domain established by PGID_SRC, by explicitly programming PGID_MCIPV4 and PGID_MCIPV6 towards all physical ports plus the CPU port module.
Fixes: a556c76adc05 ("net: mscc: Add initial Ocelot switch support") Cc: stable@kernel.org Signed-off-by: Vladimir Oltean vladimir.oltean@nxp.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/net/ethernet/mscc/ocelot.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)
--- a/drivers/net/ethernet/mscc/ocelot.c +++ b/drivers/net/ethernet/mscc/ocelot.c @@ -2153,8 +2153,12 @@ int ocelot_init(struct ocelot *ocelot) ocelot_write_rix(ocelot, ANA_PGID_PGID_PGID(GENMASK(ocelot->num_phys_ports, 0)), ANA_PGID_PGID, PGID_MC); - ocelot_write_rix(ocelot, 0, ANA_PGID_PGID, PGID_MCIPV4); - ocelot_write_rix(ocelot, 0, ANA_PGID_PGID, PGID_MCIPV6); + ocelot_write_rix(ocelot, + ANA_PGID_PGID_PGID(GENMASK(ocelot->num_phys_ports, 0)), + ANA_PGID_PGID, PGID_MCIPV4); + ocelot_write_rix(ocelot, + ANA_PGID_PGID_PGID(GENMASK(ocelot->num_phys_ports, 0)), + ANA_PGID_PGID, PGID_MCIPV6);
/* CPU port Injection/Extraction configuration */ ocelot_write_rix(ocelot, QSYS_SWITCH_PORT_MODE_INGRESS_DROP_MODE |