linux-kernel - Re: [PATCH v3 net] mv88e6060: disable hardware level MAC learning

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Message-ID: <20181228090630.GB31460@lunn.ch>
Date:   Fri, 28 Dec 2018 10:06:30 +0100
From:   Andrew Lunn <andrew@...n.ch>
To:     Pavel Machek <pavel@....cz>
Cc:     Anderson Luiz Alves <alacn1@...il.com>,
        vivien.didelot@...oirfairelinux.com, f.fainelli@...il.com,
        davem@...emloft.net, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 net] mv88e6060: disable hardware level MAC learning

On Fri, Dec 28, 2018 at 09:22:55AM +0100, Pavel Machek wrote:
> On Fri 2018-11-30 21:58:36, Anderson Luiz Alves wrote:
> > Disable hardware level MAC learning because it breaks station roaming.
> > When enabled it drops all frames that arrive from a MAC address
> > that is on a different port at learning table.
> > 
> > Signed-off-by: Anderson Luiz Alves <alacn1@...il.com>
> 
> Will not this effectively disable the hardware switching leading to
> serious performance implications?

Hi Pavel

This switch is not doing hardware switching to start with. See
mv88e6060_setup_port():

        /* Port based VLAN map: give each port its own address
         * database, allow the CPU port to talk to each of the 'real'
         * ports, and allow each of the 'real' ports to only talk to
         * the CPU port.
         */
        REG_WRITE(addr, PORT_VLAN_MAP,
                  ((p & 0xf) << PORT_VLAN_MAP_DBNUM_SHIFT) |
                   (dsa_is_cpu_port(ds, p) ? dsa_user_ports(ds) :
                    BIT(dsa_to_port(ds, p)->cpu_dp->index)));

        /* Port Association Vector: when learning source addresses
         * of packets, add the address to the address database using
         * a port bitmap that has only the bit for this port set and
         * the other bits clear.
         */
        REG_WRITE(addr, PORT_ASSOC_VECTOR, BIT(p));


This is a very old driver, added way before offload support was added.

     Andrew