Re: [PATCH RFC net-next] net: phy: add Marvell PHY PTP support [multicast/DSA issues]

From: Andrew Lunn <andrew@lunn.ch>
To: Michael Walle <michael@walle.cc>
Cc: linux@armlinux.org.uk, davem@davemloft.net, f.fainelli@gmail.com,
	hkallweit1@gmail.com, kory.maincent@bootlin.com, kuba@kernel.org,
	maxime.chevallier@bootlin.com, netdev@vger.kernel.org,
	richardcochran@gmail.com, thomas.petazzoni@bootlin.com
Subject: Re: [PATCH RFC net-next] net: phy: add Marvell PHY PTP support [multicast/DSA issues]
Date: Fri, 3 Mar 2023 14:20:20 +0100	[thread overview]
Message-ID: <ZAH0FIrZL9Wf4gvp@lunn.ch> (raw)
In-Reply-To: <20230303102005.442331-1-michael@walle.cc>

I'm not sure we are making much progress here...

Lets divide an conquer. As far as i can see we have the following bits
of work to do:

1) Kernel internal plumbing to allow multiple time stampers for one
netdev. The PTP core probably needs to be the mux for all kAPI calls,
and any internal calling between components. This might mean changes
to all MAC drivers supporting PTP and time stampers. But i don't think
there is anything too controversial here, just plumbing work.

2) Some method to allow user space to control which time stamper is
used. Either an extension of the existing IOCTL interface, or maybe
ethtool. Depending on how ambitious we want to be, add a netlink API
to eventually replace the IOCTL interface?

3) Add a device tree binding to control which time stamper is
used. Probably a MAC property. Also probably not too controversial.

4) Some solution to the default choice if there is no DT property.

	Andrew