From: Vladimir Oltean <olteanv@gmail.com>
To: Christian Eggers <ceggers@arri.de>
Cc: Richard Cochran <richardcochran@gmail.com>,
Florian Fainelli <f.fainelli@gmail.com>,
Andrew Lunn <andrew@lunn.ch>,
Vivien Didelot <vivien.didelot@gmail.com>,
Jakub Kicinski <kuba@kernel.org>,
Rob Herring <robh+dt@kernel.org>,
Helmut Grohne <helmut.grohne@intenta.de>,
Paul Barker <pbarker@konsulko.com>,
Codrin Ciubotariu <codrin.ciubotariu@microchip.com>,
George McCollister <george.mccollister@gmail.com>,
Marek Vasut <marex@denx.de>,
Tristram Ha <Tristram.Ha@microchip.com>,
"David S . Miller" <davem@davemloft.net>,
Woojung Huh <woojung.huh@microchip.com>,
Microchip Linux Driver Support <UNGLinuxDriver@microchip.com>,
netdev@vger.kernel.org, devicetree@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH net-next 7/9] net: dsa: microchip: ksz9477: add hardware time stamping support
Date: Tue, 10 Nov 2020 21:32:45 +0200 [thread overview]
Message-ID: <20201110193245.uwsmrqzio5hco7fb@skbuf> (raw)
In-Reply-To: <20201110164045.jqdwvmz5lq4hg54l@skbuf>
On Tue, Nov 10, 2020 at 06:40:45PM +0200, Vladimir Oltean wrote:
> I am fairly confident that this is how your hardware works, because
> that's also how peer delay wants to be timestamped, it seems.
So I was confident and also wrong, it appears. My KSZ9477 datasheet
says:
In the host-to-switch direction, the 4-byte timestamp field is always
present when PTP is enabled, as shown in Figure 4-6. This is true for
all packets sent by the host, including IBA packets. The host uses this
field to insert the receive timestamp from PTP Pdelay_Req messages into
the Pdelay_Resp messages. For all other traffic and PTP message types,
the host should populate the timestamp field with zeros.
Hm. Does that mean that the switch updates the originTimestamp field of
the Sync frames by itself? Ok... Very interesting that they decided to
introduce a field in the tail tag for a single type of PTP message.
But something is still wrong if you need to special-case the negative
correctionField, it looks like the arithmetic is not done on the correct
number of bits, either by the driver or by the hardware.
And zeroing out the correctionField of the Pdelay_Resp on transmission,
to put that value into t_Tail_Tag? How can you squeeze a 48-bit value
into a 32-bit value without truncation?
next prev parent reply other threads:[~2020-11-10 19:32 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-19 17:24 [RFC PATCH 0/9] net: dsa: microchip: PTP support for KSZ956x Christian Eggers
2020-10-19 17:24 ` [RFC PATCH net-next 1/9] dt-bindings: net: dsa: convert ksz bindings document to yaml Christian Eggers
2020-10-21 6:52 ` Kurt Kanzenbach
2020-10-21 8:46 ` Christian Eggers
2020-10-22 0:16 ` Vladimir Oltean
2020-10-22 0:40 ` Florian Fainelli
2020-10-22 10:54 ` Kurt Kanzenbach
2020-10-22 12:37 ` Vladimir Oltean
2020-10-22 19:17 ` Florian Fainelli
2020-10-26 13:54 ` Rob Herring
2020-10-19 17:24 ` [RFC PATCH net-next 2/9] net: dsa: microchip: split ksz_common.h Christian Eggers
2020-10-19 17:24 ` [RFC PATCH net-next 3/9] net: dsa: microchip: rename ksz9477.c to ksz9477_main.o Christian Eggers
2020-10-19 17:24 ` [RFC PATCH net-next 4/9] dt-bindings: net: dsa: microchip,ksz: add interrupt property Christian Eggers
2020-10-19 17:24 ` [RFC PATCH net-next 5/9] net: dsa: microchip: ksz9477: basic interrupt support Christian Eggers
2020-10-19 17:24 ` [RFC PATCH net-next 6/9] net: dsa: microchip: ksz9477: add Posix clock support for chip PTP clock Christian Eggers
2020-10-19 17:24 ` [RFC PATCH net-next 7/9] net: dsa: microchip: ksz9477: add hardware time stamping support Christian Eggers
2020-10-20 0:10 ` Vladimir Oltean
2020-10-20 8:39 ` Christian Eggers
2020-10-21 23:39 ` Vladimir Oltean
2020-10-22 2:42 ` Richard Cochran
2020-10-22 7:30 ` Christian Eggers
2020-10-22 10:17 ` Christian Eggers
2020-10-30 18:24 ` Vladimir Oltean
2020-11-01 9:35 ` Christian Eggers
2020-11-01 11:10 ` Vladimir Oltean
2020-11-01 22:14 ` Christian Eggers
2020-11-01 23:41 ` Vladimir Oltean
2020-11-01 23:55 ` Vladimir Oltean
2020-11-02 10:35 ` Christian Eggers
2020-11-02 12:28 ` Vladimir Oltean
2020-10-22 3:02 ` Richard Cochran
2020-10-22 9:01 ` Vladimir Oltean
2020-10-22 10:50 ` Vladimir Oltean
2020-10-22 11:11 ` Christian Eggers
2020-10-22 11:32 ` Vladimir Oltean
2020-10-22 14:34 ` Richard Cochran
2020-11-05 20:18 ` Christian Eggers
2020-11-10 1:42 ` Vladimir Oltean
2020-11-10 14:36 ` Christian Eggers
2020-11-10 16:40 ` Vladimir Oltean
2020-11-10 19:32 ` Vladimir Oltean [this message]
2020-11-11 21:49 ` Christian Eggers
2020-11-11 21:50 ` Christian Eggers
2020-11-12 15:28 ` Christian Eggers
2020-11-12 15:38 ` Vladimir Oltean
2020-11-17 11:27 ` Christian Eggers
2020-10-19 17:24 ` [RFC PATCH net-next 8/9] net: dsa: microchip: ksz9477: add Pulse Per Second (PPS) support Christian Eggers
2020-10-19 17:46 ` Vladimir Oltean
2020-10-20 8:38 ` Christian Eggers
2020-10-19 17:24 ` [RFC PATCH net-next 9/9] net: dsa: microchip: ksz9477: add periodic output support Christian Eggers
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