From:   Kurt Kanzenbach <kurt@linutronix.de>
To:     Vladimir Oltean <olteanv@gmail.com>,
        Richard Cochran <richardcochran@gmail.com>
Cc:     Martin Kaistra <martin.kaistra@linutronix.de>,
        Florian Fainelli <f.fainelli@gmail.com>,
        Andrew Lunn <andrew@lunn.ch>,
        Vivien Didelot <vivien.didelot@gmail.com>,
        "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        John Stultz <john.stultz@linaro.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Stephen Boyd <sboyd@kernel.org>,
        Russell King <linux@armlinux.org.uk>,
        Marc Kleine-Budde <mkl@pengutronix.de>,
        linux-kernel@vger.kernel.org, netdev@vger.kernel.org
Subject: Re: [PATCH 7/7] net: dsa: b53: Expose PTP timestamping ioctls to
 userspace
In-Reply-To: <20211125170518.socgptqrhrds2vl3@skbuf>
References: <20211104133204.19757-8-martin.kaistra@linutronix.de>
 <20211104174251.GB32548@hoboy.vegasvil.org>
 <ba543ae4-3a71-13fe-fa82-600ac37eaf5a@linutronix.de>
 <20211105141319.GA16456@hoboy.vegasvil.org>
 <20211105142833.nv56zd5bqrkyjepd@skbuf>
 <20211106001804.GA24062@hoboy.vegasvil.org>
 <20211106003606.qvfkitgyzoutznlw@skbuf>
 <20211107140534.GB18693@hoboy.vegasvil.org>
 <20211107142703.tid4l4onr6y2gxic@skbuf>
 <20211108144824.GD7170@hoboy.vegasvil.org>
 <20211125170518.socgptqrhrds2vl3@skbuf>
Date:   Fri, 26 Nov 2021 09:42:32 +0100
Message-ID: <87r1b3nw93.fsf@kurt>
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On Thu Nov 25 2021, Vladimir Oltean wrote:
> On Mon, Nov 08, 2021 at 06:48:24AM -0800, Richard Cochran wrote:
>> On Sun, Nov 07, 2021 at 04:27:03PM +0200, Vladimir Oltean wrote:
>> > On Sun, Nov 07, 2021 at 06:05:34AM -0800, Richard Cochran wrote:
>> > >         switch (cfg.rx_filter) {
>> > >         case HWTSTAMP_FILTER_NONE:
>> > >                 break;
>> > >         case HWTSTAMP_FILTER_ALL:
>> > >         case HWTSTAMP_FILTER_SOME:
>> > >         case HWTSTAMP_FILTER_PTP_V1_L4_EVENT:
>> > >         case HWTSTAMP_FILTER_PTP_V1_L4_SYNC:
>> > >         case HWTSTAMP_FILTER_PTP_V1_L4_DELAY_REQ:
>> > >         case HWTSTAMP_FILTER_NTP_ALL:
>> > >         case HWTSTAMP_FILTER_PTP_V2_L4_EVENT:
>> > >         case HWTSTAMP_FILTER_PTP_V2_L4_SYNC:
>> > >         case HWTSTAMP_FILTER_PTP_V2_L4_DELAY_REQ:
>> > >         case HWTSTAMP_FILTER_PTP_V2_L2_EVENT:
>> > >         case HWTSTAMP_FILTER_PTP_V2_L2_SYNC:
>> > >         case HWTSTAMP_FILTER_PTP_V2_L2_DELAY_REQ:
>> > >         case HWTSTAMP_FILTER_PTP_V2_EVENT:
>> > >         case HWTSTAMP_FILTER_PTP_V2_SYNC:
>> > >         case HWTSTAMP_FILTER_PTP_V2_DELAY_REQ:
>> > >                 cfg.rx_filter =3D HWTSTAMP_FILTER_PTP_V2_EVENT;
>> > >                 break;
>> > >         default:
>> > >                 mutex_unlock(&ocelot->ptp_lock);
>> > >                 return -ERANGE;
>> > >         }
>> > >=20
>> > > That is essentially an upgrade to HWTSTAMP_FILTER_PTP_V2_EVENT.  The
>> > > change from ALL to HWTSTAMP_FILTER_PTP_V2_EVENT is probably a simple
>> > > oversight, and the driver can be easily fixed.
>> > >=20
>> > > Thanks,
>> > > Richard
>> >=20
>> > It's essentially the same pattern as what Martin is introducing for b5=
3.
>>=20
>> Uh, no it isn't.  The present patch has:
>>=20
>> +       case HWTSTAMP_FILTER_PTP_V2_L2_EVENT:
>> +       case HWTSTAMP_FILTER_PTP_V2_L2_SYNC:
>> +       case HWTSTAMP_FILTER_PTP_V2_L2_DELAY_REQ:
>> +       case HWTSTAMP_FILTER_PTP_V2_EVENT:
>> +       case HWTSTAMP_FILTER_PTP_V2_SYNC:
>> +       case HWTSTAMP_FILTER_PTP_V2_DELAY_REQ:
>> +       case HWTSTAMP_FILTER_ALL:
>> +               config->rx_filter =3D HWTSTAMP_FILTER_PTP_V2_L2_EVENT;
>>=20
>> There is an important difference between
>> HWTSTAMP_FILTER_PTP_V2_L2_EVENT and HWTSTAMP_FILTER_PTP_V2_EVENT
>>=20
>> Notice the "L2" in there.
>
> Richard, when the request is PTP_V2_EVENT and the response is
> PTP_V2_L2_EVENT, is that an upgrade or a downgrade?

It is a downgrade, isn't it?

> PTP_V2_EVENT also includes PTP_V2_L4_EVENT.

Yes, exactly.

Thanks,
Kurt

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