ethernet<n> dt aliases implications in U-Boot and Linux

[Stephen Hemminger]

On Mon, 8 Aug 2022 23:09:45 +0200
Michal Suchánek <msuchanek at suse.de> wrote:

> On Mon, Aug 08, 2022 at 03:57:55PM -0400, Sean Anderson wrote:
> > Hi Tim,
> > 
> > On 8/8/22 3:18 PM, Tim Harvey wrote:  
> > > Greetings,
> > > 
> > > I'm trying to understand if there is any implication of 'ethernet<n>'
> > > aliases in Linux such as:
> > >         aliases {
> > >                 ethernet0 = &eqos;
> > >                 ethernet1 = &fec;
> > >                 ethernet2 = &lan1;
> > >                 ethernet3 = &lan2;
> > >                 ethernet4 = &lan3;
> > >                 ethernet5 = &lan4;
> > >                 ethernet6 = &lan5;
> > >         };
> > > 
> > > I know U-Boot boards that use device-tree will use these aliases to
> > > name the devices in U-Boot such that the device with alias 'ethernet0'
> > > becomes eth0 and alias 'ethernet1' becomes eth1 but for Linux it
> > > appears that the naming of network devices that are embedded (ie SoC)
> > > vs enumerated (ie pci/usb) are always based on device registration
> > > order which for static drivers depends on Makefile linking order and
> > > has nothing to do with device-tree.
> > > 
> > > Is there currently any way to control network device naming in Linux
> > > other than udev?  
> > 
> > You can also use systemd-networkd et al. (but that is the same kind of mechanism)
> >   
> > > Does Linux use the ethernet<n> aliases for anything at all?  
> > 
> > No :l  
> 
> Maybe it's a great opportunity for porting biosdevname to DT based
> platforms ;-)

Sorry, biosdevname was wrong way to do things.
Did you look at the internals, it was dumpster diving as root into BIOS.

Systemd-networkd does things in much more supportable manner using existing
sysfs API's.