From: Vladimir Oltean <olteanv@gmail.com>
To: Richard Cochran <richardcochran@gmail.com>
Cc: Florian Fainelli <f.fainelli@gmail.com>,
Vivien Didelot <vivien.didelot@gmail.com>,
Andrew Lunn <andrew@lunn.ch>,
"David S. Miller" <davem@davemloft.net>,
John Stultz <john.stultz@linaro.org>,
Thomas Gleixner <tglx@linutronix.de>,
Stephen Boyd <sboyd@kernel.org>,
lkml <linux-kernel@vger.kernel.org>,
netdev <netdev@vger.kernel.org>
Subject: Re: [PATCH net-next 0/5] PTP support for the SJA1105 DSA driver
Date: Fri, 31 May 2019 21:12:03 +0300 [thread overview]
Message-ID: <CA+h21houLC7TGJYQ28LxiUxyBE7ju2ZiRcUd41aGo_=uAhgVgQ@mail.gmail.com> (raw)
In-Reply-To: <CA+h21hpVrVNJTFj4DHHV+zphs2MjyRO-XZsM3D-STra+BYYHtw@mail.gmail.com>
On Fri, 31 May 2019 at 19:16, Vladimir Oltean <olteanv@gmail.com> wrote:
>
> On Fri, 31 May 2019 at 19:09, Richard Cochran <richardcochran@gmail.com> wrote:
> >
> > On Fri, May 31, 2019 at 06:23:34PM +0300, Vladimir Oltean wrote:
> > > You mean to queue it and subvert DSA's own RX timestamping callback?
> >
> > No, use the callback.
> >
> > > Why would I do that? Just so as not to introduce my .can_timestamp
> > > callback?
> >
> > Right, the .can_timestamp is unneeded, AFAICT.
> >
> > > > Now I'm starting to understand your series. I think it can be done in
> > > > simpler way...
> > > >
> > > > sja1105_rcv_meta_state_machine - can and should be at the driver level
> > > > and not at the port level.
> > > >
> > >
> > > Can: yes. Should: why?
> >
> > To keep it simple and robust.
> >
> > > One important aspect makes this need be a little bit more complicated:
> > > reconstructing these RX timestamps.
> > > You see, there is a mutex on the SPI bus, so in practice I do need the
> > > sja1105_port_rxtstamp_work for exactly this purpose - to read the
> > > timestamping clock over SPI.
> >
> > Sure. But you schedule the work after a META frame. And no busy
> > waiting is needed.
>
> Ok, I suppose this could work.
> But now comes the question on what to do on error cases - the meta
> frame didn't arrive. Should I just drop the skb waiting for it? Right
> now I "goto rcv_anyway" - which linuxptp doesn't like btw.
>
Actually I've been there before, just forgot it.
It won't work unless I make changes to dsa_switch_rcv.
Right now taggers can only return a pointer to the skb, or NULL, case
in which DSA will free it.
I'd need a mechanism to signal DSA that I'm holding up the skb for a
little bit more time, then re-engage the dsa_switch_rcv path once the
meta frame arrived.
> >
> > Thanks,
> > Richard
next prev parent reply other threads:[~2019-05-31 18:12 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-28 23:56 [PATCH net-next 0/5] PTP support for the SJA1105 DSA driver Vladimir Oltean
2019-05-28 23:56 ` [PATCH net-next 1/5] timecounter: Add helper for reconstructing partial timestamps Vladimir Oltean
2019-05-29 2:14 ` John Stultz
2019-05-29 4:40 ` Richard Cochran
2019-05-29 20:23 ` Vladimir Oltean
2019-05-28 23:56 ` [PATCH net-next 2/5] net: dsa: sja1105: Add support for the PTP clock Vladimir Oltean
2019-05-28 23:56 ` [PATCH net-next 3/5] net: dsa: mv88e6xxx: Let taggers specify a can_timestamp function Vladimir Oltean
2019-05-29 4:49 ` Richard Cochran
2019-05-29 20:33 ` Vladimir Oltean
2019-05-30 3:51 ` Richard Cochran
2019-05-30 7:42 ` Vladimir Oltean
2019-05-30 14:23 ` Richard Cochran
2019-05-30 14:40 ` Richard Cochran
2019-05-30 14:47 ` Vladimir Oltean
2019-05-30 15:01 ` Richard Cochran
2019-11-19 11:35 ` Design issue in DSA RX timestamping (Was "Re: [PATCH net-next 3/5] net: dsa: mv88e6xxx: Let taggers specify a can_timestamp function") Vladimir Oltean
2019-11-19 14:03 ` Richard Cochran
2019-05-28 23:56 ` [PATCH net-next 4/5] net: dsa: sja1105: Add support for PTP timestamping Vladimir Oltean
2019-05-28 23:56 ` [PATCH net-next 5/5] net: dsa: sja1105: Increase priority of CPU-trapped frames Vladimir Oltean
2019-05-29 4:52 ` [PATCH net-next 0/5] PTP support for the SJA1105 DSA driver Richard Cochran
2019-05-29 20:41 ` Vladimir Oltean
2019-05-30 3:45 ` Richard Cochran
2019-05-30 9:01 ` Vladimir Oltean
2019-05-30 14:30 ` Richard Cochran
2019-05-30 14:57 ` Vladimir Oltean
2019-05-30 15:05 ` Richard Cochran
2019-05-30 15:23 ` Vladimir Oltean
2019-05-31 4:34 ` Richard Cochran
2019-05-31 13:23 ` Vladimir Oltean
2019-05-31 14:08 ` Richard Cochran
2019-05-31 14:27 ` Vladimir Oltean
2019-05-31 15:11 ` Richard Cochran
2019-05-31 15:21 ` Richard Cochran
2019-05-31 15:23 ` Vladimir Oltean
2019-05-31 16:09 ` Richard Cochran
2019-05-31 16:16 ` Vladimir Oltean
2019-05-31 18:12 ` Vladimir Oltean [this message]
2019-06-01 5:07 ` Richard Cochran
2019-06-01 10:31 ` Vladimir Oltean
2019-06-01 12:06 ` Vladimir Oltean
2019-06-02 2:18 ` Richard Cochran
2019-06-02 2:17 ` Richard Cochran
2019-06-01 5:03 ` Richard Cochran
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