From: Vladimir Oltean vladimir.oltean@nxp.com
[ Upstream commit 2edcfcbb3c5946609be1d8875473a240b170673b ]
The driver implements a workaround for the fact that it doesn't have an IRQ source to tell it whether PTP frames are available through the extraction registers, for those frames to be processed and passed towards the network stack. That workaround is to configure the switch, through felix_hwtstamp_set() -> felix_update_trapping_destinations(), to create two copies of PTP packets: one sent over Ethernet to the DSA master, and one to be consumed through the aforementioned CPU extraction queue registers.
The reason why we want PTP packets to be consumed through the CPU extraction registers in the first place is because we want to see their hardware RX timestamp. With tag_8021q, that is only visible that way, and it isn't visible with the copy of the packet that's transmitted over Ethernet.
The problem with the workaround implementation is that it drops the packet received over Ethernet, in expectation of its copy being present in the CPU extraction registers. However, if felix_hwtstamp_set() hasn't run (aka PTP RX timestamping is disabled), the driver will drop the original PTP frame and there will be no copy of it in the CPU extraction registers. So, the network stack will simply not see any PTP frame.
Look at the port's trapping configuration to see whether the driver has previously enabled the CPU extraction registers. If it hasn't, just don't RX timestamp the frame and let it be passed up the stack by DSA, which is perfectly fine.
Fixes: 0a6f17c6ae21 ("net: dsa: tag_ocelot_8021q: add support for PTP timestamping") Signed-off-by: Vladimir Oltean vladimir.oltean@nxp.com Signed-off-by: Paolo Abeni pabeni@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/dsa/ocelot/felix.c | 12 ++++++++++++ 1 file changed, 12 insertions(+)
diff --git a/drivers/net/dsa/ocelot/felix.c b/drivers/net/dsa/ocelot/felix.c index 80861ac090ae3..70c0e2b1936b3 100644 --- a/drivers/net/dsa/ocelot/felix.c +++ b/drivers/net/dsa/ocelot/felix.c @@ -1725,6 +1725,18 @@ static bool felix_rxtstamp(struct dsa_switch *ds, int port, u32 tstamp_hi; u64 tstamp;
+ switch (type & PTP_CLASS_PMASK) { + case PTP_CLASS_L2: + if (!(ocelot->ports[port]->trap_proto & OCELOT_PROTO_PTP_L2)) + return false; + break; + case PTP_CLASS_IPV4: + case PTP_CLASS_IPV6: + if (!(ocelot->ports[port]->trap_proto & OCELOT_PROTO_PTP_L4)) + return false; + break; + } + /* If the "no XTR IRQ" workaround is in use, tell DSA to defer this skb * for RX timestamping. Then free it, and poll for its copy through * MMIO in the CPU port module, and inject that into the stack from