Re: [Patch net-next v3 06/13] net: ptp: add helper for one-step P2P clocks

From: Vladimir Oltean <olteanv@gmail.com>
To: Arun Ramadoss <arun.ramadoss@microchip.com>
Cc: linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
	woojung.huh@microchip.com, UNGLinuxDriver@microchip.com,
	andrew@lunn.ch, vivien.didelot@gmail.com, f.fainelli@gmail.com,
	davem@davemloft.net, edumazet@google.com, kuba@kernel.org,
	pabeni@redhat.com, linux@armlinux.org.uk,
	Tristram.Ha@microchip.com, richardcochran@gmail.com,
	ceggers@arri.de
Subject: Re: [Patch net-next v3 06/13] net: ptp: add helper for one-step P2P clocks
Date: Fri, 9 Dec 2022 17:02:51 +0200	[thread overview]
Message-ID: <20221209150251.yio23u6pbya7n5ka@skbuf> (raw)
In-Reply-To: <20221209072437.18373-7-arun.ramadoss@microchip.com>

On Fri, Dec 09, 2022 at 12:54:30PM +0530, Arun Ramadoss wrote:
> From: Christian Eggers <ceggers@arri.de>
> 
> For P2P delay measurement, the ingress time stamp of the PDelay_Req is
> required for the correction field of the PDelay_Resp. The application
> echoes back the correction field of the PDelay_Req when sending the
> PDelay_Resp.
> 
> Some hardware (like the ZHAW InES PTP time stamping IP core) subtracts
> the ingress timestamp autonomously from the correction field, so that
> the hardware only needs to add the egress timestamp on tx. Other
> hardware (like the Microchip KSZ9563) reports the ingress time stamp via
> an interrupt and requires that the software provides this time stamp via
> tail-tag on tx.
> 
> In order to avoid introducing a further application interface for this,
> the driver can simply emulate the behavior of the InES device and
> subtract the ingress time stamp in software from the correction field.
> 
> On egress, the correction field can either be kept as it is (and the
> time stamp field in the tail-tag is set to zero) or move the value from
> the correction field back to the tail-tag.
> 
> Changing the correction field requires updating the UDP checksum (if UDP
> is used as transport).
> 
> Signed-off-by: Christian Eggers <ceggers@arri.de>

Arun, this needs your Signed-off-by: tag too.
Sometimes patchwork catches tags like these and appends them to the
patch automatically when you just reply with them on a new line. Works
with Fixes:, Reviewed-by: and Acked-by: at least.

If there are no other review concerns with this series and it's
otherwise good to go, I suppose you could try that.