On Mon, 13 Mar 2023 09:40:59 +0100 Oleksij Rempel <o.rempel@xxxxxxxxxxxxxx> wrote: > > But, as you point out, with Köry's/Richard's proposal, the MAC driver > > will be bypassed when the selected timestamping layer is the PHY, and > > that's a problem currently. > > > > May I suggest the following? There was another RFC which proposed the > > introduction of a netdev notifier when timestamping is turned on/off: > > https://lore.kernel.org/netdev/20220317225035.3475538-1-vladimir.oltean@xxxxxxx/ > > > > If we have a notifier, then we can make switch drivers do things > > differently. They can activate timestamping per se in the timestamping > > NDO (which is only called when the MAC is the active timestamping layer), > > and they can activate PTP traps in the netdev notifier (which is called > > any time a timestamping status change takes place - the notifier info > > should contain details about which net_device and timestamping layer > > this is, for example). > > > > It's just a proposal of how to create an alternative notification path > > that doesn't disturb the goals of this patch set. I will take a look at your patch but indeed adding a timestamp notifier could be a good idea. > To make things even more complicated - I have a project where the DSA master > should be used for time stamping. Due to board specific limitations, we > are forced to use FEC PHC instead of dsa KSZ switch PHC. So, it is not > a choice between MAC and PHY, it is more the MAC before MAC and PHY. > PTP sync in this case will have more jitter, but it still good enough > for this project. > Currently I use quick hack to do so, but mainlinamble solution working for > most use cases will be nice. In this case it is not a PHY/MAC PTP choice anymore but more a device PTP choice which bring a lot more of complexity. Or maybe we could simply add a "switch" timestamp layer later on. As Andrew said we will maybe increase the number of timestamp layers in the future. Regards, Köry
