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Date:   Thu, 21 Apr 2022 09:38:03 +0200
From:   =?UTF-8?B?Q2zDqW1lbnQgTMOpZ2Vy?= <clement.leger@bootlin.com>
To:     Vladimir Oltean <olteanv@gmail.com>
Cc:     Andrew Lunn <andrew@lunn.ch>,
        Vivien Didelot <vivien.didelot@gmail.com>,
        Florian Fainelli <f.fainelli@gmail.com>,
        "David S . Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzk+dt@kernel.org>,
        Geert Uytterhoeven <geert+renesas@glider.be>,
        Magnus Damm <magnus.damm@gmail.com>,
        Heiner Kallweit <hkallweit1@gmail.com>,
        Russell King <linux@armlinux.org.uk>,
        Thomas Petazzoni <thomas.petazzoni@bootlin.com>,
        Herve Codina <herve.codina@bootlin.com>,
        =?UTF-8?B?TWlxdcOobA==?= Raynal <miquel.raynal@bootlin.com>,
        Milan Stevanovic <milan.stevanovic@se.com>,
        Jimmy Lalande <jimmy.lalande@se.com>,
        linux-kernel@vger.kernel.org, devicetree@vger.kernel.org,
        linux-renesas-soc@vger.kernel.org, netdev@vger.kernel.org
Subject: Re: [PATCH net-next 08/12] net: dsa: rzn1-a5psw: add FDB support
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Le Wed, 20 Apr 2022 22:52:14 +0300,
Vladimir Oltean <olteanv@gmail.com> a =C3=A9crit :

> > >=20
> > > Shouldn't this contain something along the lines of a VID, FID, somet=
hing? =20
> >=20
> > This is extracted directly from the datasheet [1]. The switch FDB table
> > does not seems to store the VID with the entries (See page 300).
> >=20
> > [1]
> > https://www.renesas.com/us/en/document/mah/rzn1d-group-rzn1s-group-rzn1=
l-group-users-manual-r-engine-and-ethernet-peripherals =20
>=20
> Thanks for the link. I see that the switch has a non-partitionable
> lookup table, not even by VLAN. A shame.
>=20
> This is also in contrast with the software bridge driver, where FDB and
> MDB entries can have independent destinations per VID.
>=20
> So there's nothing you can do beyond limiting to a single offloaded
> bridge and hoping for the best w.r.t. per-VLAN forwarding destinations.
>=20
> Note that if you limit to a single bridge does not mean that you can
> declare ds->fdb_isolation =3D true. Declaring that would opt you into
> unicast and multicast filtering towards the CPU, i.o.w. a method for
> software to only receive the addresses it has expressed an interest in,
> rather than all packets received on standalone ports. The way that is
> implemented in DSA is by adding FDB and MDB entries on the management
> port, and it would break a lot of things without a partitioning scheme
> for the lookup table.

Thanks Vladimir, it confirms what I thought.

--=20
Cl=C3=A9ment L=C3=A9ger,
Embedded Linux and Kernel engineer at Bootlin
https://bootlin.com