Subject: Re: [PATCH net-next] net: dsa: mv88e6xxx: Enable PTP receive for mv88e6390

From: Kurt Kanzenbach <[email-masked]>
Date: Wed, 11 Jan 2023 15:20:56 +0100

On Wed Jan 11 2023, Andrew Lunn wrote:
> On Wed, Jan 11, 2023 at 09:04:17AM +0100, Kurt Kanzenbach wrote:
>> The switch receives management traffic such as STP and LLDP. However, PTP
>> messages are not received, only transmitted.
>> 
>> Ideally, the switch would trap all PTP messages to the management CPU. This
>> particular switch has a PTP block which identifies PTP messages and traps them
>> to a dedicated port. There is a register to program this destination. This is
>> not used at the moment.
>> 
>> Therefore, program it to the same port as the MGMT traffic is trapped to. This
>> allows to receive PTP messages as soon as timestamping is enabled.
>> 
>> In addition, the datasheet mentions that this register is not valid e.g. for
>> 6190 variants. So, add a new cpu port method for 6390 which programs the MGTM
>> and PTP destination.
>
> The mv88e6190x_ops and ops mv88e6190_ops structure does not have a
> ptp_ops member. So these two devices do not support PTP.
>
> I think it would be cleaner to implement setting the PTP MGMT port as
> part of the ptp_ops. Maybe add a new op, which is called from
> mv88e6xxx_ptp_setup() if set?

OK, can do. The 6390 currently uses mv88e6352_ptp_ops. This one is used
by a lot of other devices, too. For instance, the 6341 doesn't have this
PTP MGMT port, but uses the same ops structure. Thus, I'd have to
introduce a new ptp ops structure for both 6390 devices.

Thanks,
Kurt