Re: Testing selectable timestamping - where are the tools for this feature?

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

On Wed, Nov 13, 2024 at 05:14:43PM +0100, Kory Maincent wrote:
> On Wed, 13 Nov 2024 15:57:56 +0000
> "Russell King (Oracle)" <linux@armlinux.org.uk> wrote:
> 
> > On Wed, Nov 13, 2024 at 04:16:02PM +0100, Kory Maincent wrote:
> > > Hello Russell,
> > > 
> > > On Wed, 13 Nov 2024 14:46:25 +0000
> > > "Russell King (Oracle)" <linux@armlinux.org.uk> wrote:
> > >   
> > > > Hi Kory,
> > > > 
> > > > I've finally found some cycles (and time when I'm next to the platform)
> > > > to test the selectable timestamping feature. However, I'm struggling to
> > > > get it to work.
> > > > 
> > > > In your email
> > > > https://lore.kernel.org/20240709-feature_ptp_netnext-v17-0-b5317f50df2a@bootlin.com/
> > > > you state that "You can test it with the ethtool source on branch
> > > > feature_ptp of: https://github.com/kmaincent/ethtool". I cloned this
> > > > repository, checked out the feature_ptp branch, and while building
> > > > I get the following warnings:
> > > > 
> > > > My conclusion is... your ethtool sources for testing this feature are
> > > > broken, or this is no longer the place to test this feature.  
> > > 
> > > Yeah, it was for v3 of the patch series. It didn't follow up to v19, I am
> > > using ynl tool which is the easiest way to test it.
> > > As there were a lot of changes along the way, updating ethtool every time
> > > was not a good idea.
> > > 
> > > Use ynl tool. Commands are described in the last patch of the series:
> > > https://lore.kernel.org/all/20241030-feature_ptp_netnext-v19-10-94f8aadc9d5c@bootlin.com/
> > > 
> > > You simply need to install python python-yaml and maybe others python
> > > subpackages.
> > > Copy the tool "tools/net/ynl" and the specs "Documentation/netlink/" on the
> > > board.
> > > 
> > > Then run the ynl commands.  
> > 
> > Thanks... fairly unweildly but at least it's functional. However,
> > running the first, I immediately find a problem:
> > 
> > # ./ynl/cli.py --spec netlink/specs/ethtool.yaml --no-schema --dump
> > tsinfo-get --json '{"header":{"dev-name":"eth0"}}'
> > 
> > One would expect this to only return results for eth0 ?
> 
> Indeed it should! That's weird, I will investigate.
> 
> > Also, I don't see more than one timestamper on any interface - there
> > should be two on eth2, one for the MAC and one for the PHY. I see the
> > timestamper for the mvpp2 MAC, but nothing for the PHY. The PTP clock
> > on the PHY is definitely registered (/dev/ptp0), which means
> > phydev->mii_ts should be pointing to the MII timestamper for the PHY.
> > 
> > I've also tried with --json '{"header":{"dev-name":"eth2"}}' but no
> > difference - it still reports all interfaces and only one timestamper
> > for eth2.
> 
> Sorry forgot to explain that you need to register PTP clock with the function
> phydev_ptp_clock_register() in the PHY driver.

That is certainly inconvenient. Marvell's PHY PTP/TAI implementation is
used elsewhere, so the TAI driver is not specific to it being on a PHY.
The drivers/ptp/marvell*.c that you find in my patches is meant to
eventually replace drivers/net/dsa/mv88e6xxx/ptp.c - the same hardware
block is in Marvell's DSA switches.

> It will be changed in v20 as request by Jakub. I will save the hwtstamp source
> and phydev pointer in the netdev core instead.

I think I'll shelve this until that happens, hopefully that will mean
my existing code will work and remain a re-usable library.

-- 
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