Re: [PATCH 0/4] RFC CPSW switchdev mode

Grygorii Strashko
2018-06-05T21:42:24Z

On 06/05/2018 04:28 PM, Andrew Lunn wrote:
>> I hope you are right - question is always in number of available options
>> and which one to select - and, most important, explain it to the end user :(
>
> The end customer being ptp4linux? At least for Marvell switches, it is
> happy about everything except that the switch is a bit slow, so we
> need to modify some of the time outs in the configuration file.
>
>> For example:
>> phc_index is returned as part of .get_ts_info() = cpsw_get_ts_info(),
>> so which intf should return phc_index?
>
> It is not a 1:1 relationship. See:
>
> https://elixir.bootlin.com/linux/latest/source/drivers/net/dsa/mv88e6xxx/hwtstamp.c#L61
>
> All interfaces return the same index.
>
> In fact, for a switch, having a PHC per port would be odd. That would
> mean you need to sync the PHCs in order to act as a boundary clock.

PHC only one, but hw timestamping blocks are per port.

--
regards,
-grygorii