Subject: Re: [PATCH v2 2/2] net: ethernet: Add driver for Sunplus SP7021

From: Andrew Lunn <[email-masked]>
Date: Tue, 16 Nov 2021 23:15:03 +0100

> > > +static const char def_mac_addr[ETHERNET_MAC_ADDR_LEN] = {
> > > +	0xfc, 0x4b, 0xbc, 0x00, 0x00, 0x00
> > 
> > This does not have the locally administered bit set. Should it? Or is this and address
> > from your OUI?
> 
> This is default MAC address when MAC address in NVMEM is not found.
> Fc:4b:bc:00:00:00 is OUI of "Sunplus Technology Co., Ltd.".
> Can I keep this? or it should be removed?

Please add a comment about whos OUI it is.

It is however more normal to use a random MAC address if no other MAC
address is available. That way, you avoid multiple devices on one LAN
using the same default MAC address.

> > > +	if (mac->next_ndev) {
> > > +		struct net_device *ndev2 = mac->next_ndev;
> > > +
> > > +		if (!netif_carrier_ok(ndev2) && (reg & PORT_ABILITY_LINK_ST_P1)) {
> > > +			netif_carrier_on(ndev2);
> > > +			netif_start_queue(ndev2);
> > > +		} else if (netif_carrier_ok(ndev2) && !(reg & PORT_ABILITY_LINK_ST_P1)) {
> > > +			netif_carrier_off(ndev2);
> > > +			netif_stop_queue(ndev2);
> > > +		}
> > 
> > Looks very odd. The two netdev should be independent.
> 
> I don't understand your comment.
> ndev checks PORT_ABILITY_LINK_ST_P0
> ndev2 checks PORT_ABILITY_LINK_ST_P1
> They are independent already.

I would try to remove the mac->next_ndev. I think without that, you
will get a cleaner abstraction. You might want to keep an array of mac
pointers in your top level shared structure.

	 Andrew