Date:   Thu, 9 Feb 2023 09:40:06 +0100
From:   =?UTF-8?B?Q2zDqW1lbnQgTMOpZ2Vy?= <clement.leger@bootlin.com>
To:     Vladimir Oltean <olteanv@gmail.com>
Cc:     Andrew Lunn <andrew@lunn.ch>,
        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>,
        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>,
        Pascal Eberhard <pascal.eberhard@se.com>,
        Arun Ramadoss <Arun.Ramadoss@microchip.com>,
        linux-renesas-soc@vger.kernel.org, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH net-next v3 1/3] net: dsa: rzn1-a5psw: use
 a5psw_reg_rmw() to modify flooding resolution
Message-ID: <20230209094006.66ce1409@fixe.home>
In-Reply-To: <20230208213757.iyofbkmvww6r4luy@skbuf>
References: <20230208161749.331965-1-clement.leger@bootlin.com>
        <20230208161749.331965-2-clement.leger@bootlin.com>
        <20230208213757.iyofbkmvww6r4luy@skbuf>
Organization: Bootlin
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Le Wed, 8 Feb 2023 23:37:57 +0200,
Vladimir Oltean <olteanv@gmail.com> a =C3=A9crit :

> On Wed, Feb 08, 2023 at 05:17:47PM +0100, Cl=C3=A9ment L=C3=A9ger wrote:
> > .port_bridge_flags will be added and allows to modify the flood mask
> > independently for each port. Keeping the existing bridged_ports write
> > in a5psw_flooding_set_resolution() would potentially messed up this.
> > Use a read-modify-write to set that value and move bridged_ports
> > handling in bridge_port_join/leave.
> >=20
> > Signed-off-by: Cl=C3=A9ment L=C3=A9ger <clement.leger@bootlin.com>
> > ---
> >  drivers/net/dsa/rzn1_a5psw.c | 12 ++++++------
> >  1 file changed, 6 insertions(+), 6 deletions(-)
> >=20
> > diff --git a/drivers/net/dsa/rzn1_a5psw.c b/drivers/net/dsa/rzn1_a5psw.c
> > index 919027cf2012..8b7d4a371f8b 100644
> > --- a/drivers/net/dsa/rzn1_a5psw.c
> > +++ b/drivers/net/dsa/rzn1_a5psw.c
> > @@ -299,13 +299,9 @@ static void a5psw_flooding_set_resolution(struct a=
5psw *a5psw, int port,
> >  			A5PSW_MCAST_DEF_MASK};
> >  	int i;
> > =20
> > -	if (set)
> > -		a5psw->bridged_ports |=3D BIT(port);
> > -	else
> > -		a5psw->bridged_ports &=3D ~BIT(port);
> > -
> >  	for (i =3D 0; i < ARRAY_SIZE(offsets); i++)
> > -		a5psw_reg_writel(a5psw, offsets[i], a5psw->bridged_ports);
> > +		a5psw_reg_rmw(a5psw, offsets[i], BIT(port),
> > +			      set ? BIT(port) : 0);
> >  }
> > =20
> >  static int a5psw_port_bridge_join(struct dsa_switch *ds, int port,
> > @@ -326,6 +322,8 @@ static int a5psw_port_bridge_join(struct dsa_switch=
 *ds, int port,
> >  	a5psw_flooding_set_resolution(a5psw, port, true);
> >  	a5psw_port_mgmtfwd_set(a5psw, port, false);
> > =20
> > +	a5psw->bridged_ports |=3D BIT(port);
> > +
> >  	return 0;
> >  }
> > =20
> > @@ -334,6 +332,8 @@ static void a5psw_port_bridge_leave(struct dsa_swit=
ch *ds, int port,
> >  {
> >  	struct a5psw *a5psw =3D ds->priv;
> > =20
> > +	a5psw->bridged_ports &=3D ~BIT(port);
> > +
> >  	a5psw_flooding_set_resolution(a5psw, port, false);
> >  	a5psw_port_mgmtfwd_set(a5psw, port, true);
> > =20
> > --=20
> > 2.39.0
> >  =20
>=20
> What about the a5psw_flooding_set_resolution() call for the CPU port, fro=
m a5psw_setup()?
> Isn't this an undocumented change? Does this logic in a5psw_port_bridge_l=
eave() still work,
> now that bridged_ports will no longer contain BIT(A5PSW_CPU_PORT)?
>=20
> 	/* No more ports bridged */
> 	if (a5psw->bridged_ports =3D=3D BIT(A5PSW_CPU_PORT))
> 		a5psw->br_dev =3D NULL;

You are right, this actually disallow to create a bridge multiple
times. I'll fix that.

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