From: Richard Cochran <richardcochran@gmail.com>
To: Vladimir Oltean <olteanv@gmail.com>
Cc: Sergey Organov <sorganov@gmail.com>,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
Fugang Duan <fugang.duan@nxp.com>,
"David S. Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>,
andrew@lunn.ch
Subject: Re: [PATCH 1/5] net: fec: properly support external PTP PHY for hardware time stamping
Date: Wed, 8 Jul 2020 04:00:53 -0700 [thread overview]
Message-ID: <20200708110053.GC9080@hoboy> (raw)
In-Reply-To: <20200707070437.gyfoulyezi6ubmdv@skbuf>
On Tue, Jul 07, 2020 at 10:04:37AM +0300, Vladimir Oltean wrote:
> > > We do it like this:
> > > - DSA: If there is a timestamping switch stacked on top of a
> > > timestamping Ethernet MAC, the switch hijacks the .ndo_do_ioctl of the
> > > host port, and you are supposed to use the PTP clock of the switch,
> > > through the .ndo_do_ioctl of its own (virtual) net devices. This
> > > approach works without changing any code in each individual Ethernet
> > > MAC driver.
> > > - PHY: The Ethernet MAC driver needs to be kind enough to check whether
> > > the PHY supports hw timestamping, and pass this ioctl to that PHY
> > > while making sure it doesn't do anything stupid in the meanwhile, like
> > > also acting upon that timestamping request itself.
> > >
> > > Both are finicky in their own ways. There is no real way for the user to
> > > select which PHC they want to use. The assumption is that you'd always
> > > want to use the outermost one, and that things in the kernel side always
> > > collaborate towards that end.
Vladimir, your explanations in this thread are valuable. Please
consider converting them into a patch to expand
Documentation/networking/timestamping.rst
Thanks,
Richard
next prev parent reply other threads:[~2020-07-08 11:00 UTC|newest]
Thread overview: 66+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-06 14:26 [PATCH 0/5] net: fec: fix external PTP PHY support Sergey Organov
2020-07-06 14:26 ` [PATCH 1/5] net: fec: properly support external PTP PHY for hardware time stamping Sergey Organov
2020-07-06 15:08 ` Vladimir Oltean
2020-07-06 15:21 ` Sergey Organov
2020-07-06 15:47 ` Vladimir Oltean
2020-07-06 18:33 ` Sergey Organov
2020-07-07 7:04 ` Vladimir Oltean
2020-07-07 15:29 ` Sergey Organov
2020-07-08 11:00 ` Richard Cochran [this message]
2020-07-08 10:55 ` Richard Cochran
2020-07-06 14:26 ` [PATCH 2/5] net: fec: enable to use PPS feature without " Sergey Organov
2020-07-07 4:05 ` [EXT] " Andy Duan
2020-07-07 14:29 ` Sergey Organov
2020-07-06 14:26 ` [PATCH 3/5] net: fec: initialize clock with 0 rather than current kernel time Sergey Organov
2020-07-06 15:27 ` Vladimir Oltean
2020-07-06 18:24 ` Sergey Organov
2020-07-07 6:36 ` Vladimir Oltean
2020-07-07 16:07 ` Sergey Organov
2020-07-07 16:43 ` Vladimir Oltean
2020-07-07 17:09 ` Sergey Organov
2020-07-07 17:12 ` Vladimir Oltean
2020-07-07 17:56 ` Sergey Organov
2020-07-08 11:15 ` Richard Cochran
2020-07-08 12:14 ` Sergey Organov
2020-07-08 11:11 ` Richard Cochran
2020-07-08 11:04 ` Richard Cochran
2020-07-08 12:24 ` Sergey Organov
2020-07-08 12:37 ` Sergey Organov
2020-07-08 14:48 ` Richard Cochran
2020-07-08 17:18 ` Sergey Organov
2020-07-06 14:26 ` [PATCH 4/5] net: fec: get rid of redundant code in fec_ptp_set() Sergey Organov
2020-07-07 4:08 ` [EXT] " Andy Duan
2020-07-07 14:43 ` Sergey Organov
2020-07-08 5:34 ` Andy Duan
2020-07-08 8:48 ` Sergey Organov
2020-07-08 8:57 ` Andy Duan
2020-07-08 12:26 ` Sergey Organov
2020-07-06 14:26 ` [PATCH 5/5] net: fec: replace snprintf() with strlcpy() in fec_ptp_init() Sergey Organov
2020-07-11 12:08 ` [PATCH v2 net] net: fec: fix hardware time stamping by external devices Sergey Organov
2020-07-11 23:19 ` Vladimir Oltean
2020-07-12 14:16 ` Sergey Organov
2020-07-12 14:47 ` Andrew Lunn
2020-07-12 15:01 ` Vladimir Oltean
2020-07-12 17:29 ` Sergey Organov
2020-07-12 19:33 ` Vladimir Oltean
2020-07-12 22:32 ` Sergey Organov
2020-07-12 23:15 ` Vladimir Oltean
2020-07-14 12:39 ` Sergey Organov
2020-07-14 14:23 ` Vladimir Oltean
2020-07-14 14:35 ` Sergey Organov
2020-07-14 14:44 ` Vladimir Oltean
2020-07-14 16:18 ` Sergey Organov
2020-07-14 14:01 ` Richard Cochran
2020-07-14 14:27 ` Sergey Organov
2020-07-14 16:28 ` [PATCH v3 " Sergey Organov
2020-07-16 18:24 ` Jakub Kicinski
2020-07-16 20:38 ` Sergey Organov
2020-07-16 21:06 ` Jakub Kicinski
2020-07-16 21:18 ` Sergey Organov
2020-07-15 15:42 ` [PATCH net-next v2 0/4] net: fec: a few improvements Sergey Organov
2020-07-15 15:42 ` [PATCH net-next v2 1/4] net: fec: enable to use PPS feature without time stamping Sergey Organov
2020-07-15 15:42 ` [PATCH net-next v2 2/4] net: fec: initialize clock with 0 rather than current kernel time Sergey Organov
2020-07-15 15:42 ` [PATCH net-next v2 3/4] net: fec: get rid of redundant code in fec_ptp_set() Sergey Organov
2020-07-15 15:43 ` [PATCH net-next v2 4/4] net: fec: replace snprintf() with strlcpy() in fec_ptp_init() Sergey Organov
2020-07-16 3:00 ` [EXT] [PATCH net-next v2 0/4] net: fec: a few improvements Andy Duan
2020-07-16 18:37 ` Jakub Kicinski
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