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

On 8/11/26 01:06, Jonas Gorski wrote:
> On Mon, Aug 10, 2026 at 2:04 PM Vladimir Oltean <[email protected]> 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