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From:   =?UTF-8?Q?Pawe=C5=82_Dembicki?= <paweldembicki@gmail.com>
Date:   Sun, 25 Jun 2023 13:47:31 +0200
Message-ID: <CAJN1KkxahD-Rh+77NRJnkUwvZY547f06ZoThmoqSp8SBs3mnnA@mail.gmail.com>
Subject: Re: [PATCH net-next 2/6] net: dsa: vsc73xx: add port_stp_state_set function
To:     Vladimir Oltean <olteanv@gmail.com>
Cc:     Linus Walleij <linus.walleij@linaro.org>,
        Andrew Lunn <andrew@lunn.ch>, netdev@vger.kernel.org,
        Florian Fainelli <f.fainelli@gmail.com>,
        "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>, linux-kernel@vger.kernel.org
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niedz., 25 cze 2023 o 13:21 Vladimir Oltean <olteanv@gmail.com> napisa=C5=
=82(a):
>
> On Wed, Jun 21, 2023 at 11:27:14PM +0200, Linus Walleij wrote:
> > On Wed, Jun 21, 2023 at 9:33=E2=80=AFPM Andrew Lunn <andrew@lunn.ch> wr=
ote:
> >
> > > > +     struct vsc73xx *vsc =3D ds->priv;
> > > > +     /* FIXME: STP frames isn't forwarded at this moment. BPDU fra=
mes are
> > > > +      * forwarded only from to PI/SI interface. For more info see =
chapter
> > > > +      * 2.7.1 (CPU Forwarding) in datasheet.
> > >
> > > Do you mean the CPU never gets to see the BPDU frames?
> > >
> > > Does the hardware have any sort of packet matching to trap frames to
> > > the CPU? Can you match on the destination MAC address
> > > 01:80:C2:00:00:00 ?
> >
> > The hardware contains an embedded Intel 8054 CPU that can
> > execute programs to do pretty much anything.
> >
> > The bad news: it requires a custom SDK thingy that we do not
> > have access to.
> >
> > So far we used the chips in a bit of vanilla mode, which is all I
> > have ever seen in the systems we have and it can't do much,
> > not even add a helpful frame tag, but as can be seen from the
> > patches it can do VLAN...
> >
> > Yours,
> > Linus Walleij
>
> But even without involving the iCPU, it should be possible to inject/extr=
act
> control packets over the SI interface, using the CPU_CAPT and CPUTXDAT bl=
ock
> registers, correct?

Yes , It should work with CPU_CAPT and CPUTXDAT.

>
> IIUC, ocelot with tag_8021q does just that for STP and PTP, see
> ocelot_port_inject_frame() and ocelot_xtr_poll_frame().

I was planning to do it in the next step after making this driver
however usable.

--
Pawel Dembicki