Re: [PATCH net-next v2 2/2] net: phy: Add Marvell PHY PTP support

["Russell King (Oracle)" <linux@armlinux.org.uk>]

On Thu, Apr 10, 2025 at 07:16:47PM +0100, Russell King (Oracle) wrote:
> On Thu, Apr 10, 2025 at 06:02:05PM +0200, Kory Maincent wrote:
> > On Thu, 10 Apr 2025 16:41:06 +0100
> > "Russell King (Oracle)" <linux@armlinux.org.uk> wrote:
> > 
> > > On Thu, Apr 10, 2025 at 11:17:54AM +0200, Kory Maincent wrote:
> > > > On Wed, 9 Apr 2025 23:38:00 +0100
> > > > "Russell King (Oracle)" <linux@armlinux.org.uk> wrote:  
> > > > > On Wed, Apr 09, 2025 at 06:34:35PM +0100, Russell King (Oracle) wrote:  
> > 
> > > > > 
> > > > > With that fixed, ptp4l's output looks very similar to that with mvpp2 -
> > > > > which doesn't inspire much confidence that the ptp stack is operating
> > > > > properly with the offset and frequency varying all over the place, and
> > > > > the "delay timeout" messages spamming frequently. I'm also getting
> > > > > ptp4l going into fault mode - so PHY PTP is proving to be way more
> > > > > unreliable than mvpp2 PTP. :(  
> > > > 
> > > > That's really weird. On my board the Marvell PHY PTP is more reliable than
> > > > MACB. Even by disabling the interrupt.
> > > > What is the state of the driver you are using?   
> > > 
> > > Right, it seems that some of the problems were using linuxptp v3.0
> > > rather than v4.4, which seems to work better (in that it doesn't
> > > seem to time out and drop into fault mode.)
> > > 
> > > With v4.4, if I try:
> > > 
> > > # ./ptp4l -i eth2 -m -s -2
> > > ptp4l[322.396]: selected /dev/ptp0 as PTP clock
> > > ptp4l[322.453]: port 1 (eth2): INITIALIZING to LISTENING on INIT_COMPLETE
> > > ptp4l[322.454]: port 0 (/var/run/ptp4l): INITIALIZING to LISTENING on
> > > INIT_COMPLETE ptp4l[322.455]: port 0 (/var/run/ptp4lro): INITIALIZING to
> > > LISTENING on INIT_COMPLETE ptp4l[328.797]: selected local clock
> > > 005182.fffe.113302 as best master
> > > 
> > > that's all I see. If I drop the -2, then:
> > 
> > It seems you are still using your Marvell PHY drivers without my change.
> > PTP L2 was broken on your first patch and I fixed it.
> > I have the same result without the -2 which mean ptp4l uses UDP IPV4.
> 
> I'm not sure what you're referring to.

Okay, turns out to be nothing to do with any fixes in my code or not
(even though I still don't know what the claimed brokenness you
refer to actually was.)

It turns out to be that ptpdv2 sends PTP packets using IPv4 UDP *or*
L2, and was using IPv4 UDP. Adding "ptpengine:transport=ethernet" to
the ptpdv2 configuration allows ptp4l -2 to then work.

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
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