Re: [PATCH net] net: dsa: b53: be VLAN unaware when not filtering

[Florian Fainelli]

On 8/11/26 01:06, Jonas Gorski wrote:
> On Mon, Aug 10, 2026 at 2:04 PM Vladimir Oltean <olteanv@xxxxxxxxx> wrote:
> > On Thu, Aug 06, 2026 at 01:09:03PM +0200, Jonas Gorski wrote:
> > > > static int b53_arl_rw_op(struct b53_device *dev, unsigned int op)
> > > > {
> > > >          u8 reg;
> > > >
> > > >          if (op > ARLTBL_RW)
> > > >                  return -EINVAL;
> > > >
> > > >          b53_read8(dev, B53_ARLIO_PAGE, B53_ARLTBL_RW_CTRL, &reg);
> > > >          reg |= ARLTBL_START_DONE;
> > > >          if (op)
> > > >                  reg |= ARLTBL_RW;
> > > >          else
> > > >                  reg &= ~ARLTBL_RW;
> > > >          if (dev->vlan_enabled)
> > > >                  reg &= ~ARLTBL_IVL_SVL_SELECT;
> > > >          else
> > > >                  reg |= ARLTBL_IVL_SVL_SELECT;
> > >
> > > This ARLTBL_IVL_SVL_SELECT bit is only implemented for a small subset
> > > of switches (bcm5302x / bcm58* and bcm53134). Additionally, according
> > > to the register description, this also requires enabling "per port
> > > IVL/SVL" mode, which is not enable by b53. The description of that
> > > also says that the VIDs used in SVL ports must not be used in IVL
> > > ports. No idea what the consequences are if they do.
> >
> > What does enabling per port IVL/SVL mode do?
>
> I don't have access to a datasheet or a device to test, Florian will
> need to answer that completely.

Not a whole lot of details in the datasheet, but essentially what is 
being provided is:

IVL: a given MAC address can only appear in one VLAN
SVL: a given MAC address can appear on different ports as long as the 
ports are not in the same VLAN.

> I can only guess from the register descriptions, which imply that
> enabling SVL for port makes any ARL lookups SVL based, i.e. VID is
> ignored/forced to 0. Presumably this essentially only applies to for
> frames received on that port for lookup / learning.
>
> There is a global option for configuring IVL or SVL, but this option
> is only valid when VLAN-aware is enabled in the switch. Without it,
> learning is always SVL.
>
> I do not know how the per port IVL/SVL actually register works, and
> whether you can enable IVL in VLAN-unaware mode (I would guess not).

IVL/SVL applies to 802.1Q (VLAN enabled) mode, double tagging mode and 
individual double tagging mode, so yes this depends on VLAN being 
enabled globally.

> Note that there is no differentiation in ARL entries themselves
> whether they are IVL or SVL entries, only the table index calculation
> changes.
>
> Best regards,
> Jonas


--
Florian