Re: [RFC PATCH 04/10] net: dsa: b53: fix IP_MULTICAST_CTRL on BCM5325

[Jonas Gorski]

On Mon, Jun 2, 2025 at 8:06 PM Florian Fainelli
<florian.fainelli@xxxxxxxxxxxx> wrote:
>
> On 5/31/25 03:13, Álvaro Fernández Rojas wrote:
> > BCM5325 doesn't implement B53_UC_FWD_EN, B53_MC_FWD_EN or B53_IPMC_FWD_EN.
> >
> > Fixes: 53568438e381 ("net: dsa: b53: Add support for port_egress_floods callback")
> > Signed-off-by: Álvaro Fernández Rojas <noltari@xxxxxxxxx>
> > ---
> >   drivers/net/dsa/b53/b53_common.c | 13 +++++++++----
> >   drivers/net/dsa/b53/b53_regs.h   |  1 +
> >   2 files changed, 10 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/net/dsa/b53/b53_common.c b/drivers/net/dsa/b53/b53_common.c
> > index f314aeb81643..6b2ad82aa95f 100644
> > --- a/drivers/net/dsa/b53/b53_common.c
> > +++ b/drivers/net/dsa/b53/b53_common.c
> > @@ -367,11 +367,16 @@ static void b53_set_forwarding(struct b53_device *dev, int enable)
> >               b53_write8(dev, B53_CTRL_PAGE, B53_SWITCH_CTRL, mgmt);
> >       }
> >
> > -     /* Look at B53_UC_FWD_EN and B53_MC_FWD_EN to decide whether
> > -      * frames should be flooded or not.
> > -      */
> >       b53_read8(dev, B53_CTRL_PAGE, B53_IP_MULTICAST_CTRL, &mgmt);
> > -     mgmt |= B53_UC_FWD_EN | B53_MC_FWD_EN | B53_IPMC_FWD_EN;
> > +     if (is5325(dev)) {
> > +             /* Enable IP multicast address scheme. */
> > +             mgmt |= B53_IP_MCAST_25;
> > +     } else {
> > +             /* Look at B53_UC_FWD_EN and B53_MC_FWD_EN to decide whether
> > +              * frames should be flooded or not.
> > +              */
> > +             mgmt |= B53_UC_FWD_EN | B53_MC_FWD_EN | B53_IPMC_FWD_EN;
> > +     }
> >       b53_write8(dev, B53_CTRL_PAGE, B53_IP_MULTICAST_CTRL, mgmt);

Since the only common thing is the register name, maybe it would make
more sense to have the flow here

if (is5325) {
    enable IP_MULTICAST
}  else {
    enable DUMB_FWD_EN
    enable {UC,MC,IPMC}_FWD_EN
}

>
> I don't think B53_IPM_MULTICAST_CTRL is a valid register offset within
> B53_CTRL_PAGE, or elsewhere for that matter, do you have a datasheet
> that says this exists?

5325E-DS14-R, page 83 (or 105 in pdf paging) on the top.

Regards,
Jonas