Re: [net-next PATCH v16 10/10] net: dsa: tag_mtk: add comments about Airoha usage of this TAG

[Christian Marangi <ansuelsmth@gmail.com>]

On Wed, Sep 10, 2025 at 11:20:17AM +0300, Vladimir Oltean wrote:
> On Tue, Sep 09, 2025 at 02:43:41AM +0200, Christian Marangi wrote:
> > Add comments about difference between Airoha AN8855 and Mediatek tag
> > bitmap.
> > 
> > Airoha AN88555 doesn't support controlling SA learning and Leaky VLAN
> 
> Is there an extra 5 in AN88555?
> 
> > from tag. Although these bits are not used (and even not defined for
> > Leaky VLAN), it's worth to add comments for these difference to prevent
> > any kind of regression in the future if ever these bits will be used.
> > 
> > Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
> > ---
> >  net/dsa/tag_mtk.c | 3 +++
> >  1 file changed, 3 insertions(+)
> > 
> > diff --git a/net/dsa/tag_mtk.c b/net/dsa/tag_mtk.c
> > index b670e3c53e91..ac3f956abe39 100644
> > --- a/net/dsa/tag_mtk.c
> > +++ b/net/dsa/tag_mtk.c
> > @@ -18,6 +18,9 @@
> >  #define MTK_HDR_XMIT_TAGGED_TPID_88A8	2
> >  #define MTK_HDR_RECV_SOURCE_PORT_MASK	GENMASK(2, 0)
> >  #define MTK_HDR_XMIT_DP_BIT_MASK	GENMASK(5, 0)
> > +/* AN8855 doesn't support SA_DIS and Leaky VLAN
> > + * control in tag as these bits doesn't exist.
> > + */
> 
> I think it would be good to present the AN8855 tag using a different
> string, so that libpcap knows it shouldn't decode these bits. The code
> can be reused for now.
>

Do you think I can implement 2 tagger in the same driver or do I need to
make a library of this driver? Just asking what is the correct way to
generalize it.

> >  #define MTK_HDR_XMIT_SA_DIS		BIT(6)
> >  
> >  static struct sk_buff *mtk_tag_xmit(struct sk_buff *skb,
> > -- 
> > 2.51.0
> > 
> 

-- 
	Ansuel