Re: [PATCH RFC net-next] net: phy: add Marvell PHY PTP support

From: Richard Cochran <richardcochran@gmail.com>
To: Russell King - ARM Linux admin <linux@armlinux.org.uk>
Cc: Andrew Lunn <andrew@lunn.ch>,
	Florian Fainelli <f.fainelli@gmail.com>,
	Heiner Kallweit <hkallweit1@gmail.com>,
	"David S. Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>,
	netdev@vger.kernel.org
Subject: Re: [PATCH RFC net-next] net: phy: add Marvell PHY PTP support
Date: Thu, 30 Jul 2020 08:53:26 -0700	[thread overview]
Message-ID: <20200730155326.GB28298@hoboy> (raw)
In-Reply-To: <20200729220748.GW1605@shell.armlinux.org.uk>

On Wed, Jul 29, 2020 at 11:07:48PM +0100, Russell King - ARM Linux admin wrote:
> What I see elsewhere in ethtool is that the MAC has the ability to
> override the phylib provided functionality - for example,
> __ethtool_get_sset_count(), __ethtool_get_strings(), and
> ethtool_get_phy_stats().  Would it be possible to do the same in
>  __ethtool_get_ts_info(), so at least a MAC driver can then decide
> whether to propagate the ethtool request to phylib or not, just like
> it can do with the SIOC*HWTSTAMP ioctls?  Essentially, reversing the
> order of:
> 
>         if (phy_has_tsinfo(phydev))
>                 return phy_ts_info(phydev, info);
>         if (ops->get_ts_info)
>                 return ops->get_ts_info(dev, info);
> 
> ?

I don't see a simple solution.  I think no matter what, the MAC
drivers need work to allow PHY time stamping, and the great majority
of users and driver authors are happy with MAC time stamping.

Thanks,
Richard