ethernet<n> dt aliases implications in U-Boot and Linux
Florian Fainelli
f.fainelli at gmail.com
Mon Aug 8 23:18:59 CEST 2022
On 8/8/22 12:57, 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
It is actually used, but by individual drivers, not by the networking
stack AFAICT:
git grep -E "of_alias_get_id\((.*), \"(eth|ethernet)\"\)" *
drivers/net/ethernet/broadcom/genet/bcmmii.c: id =
of_alias_get_id(dn, "eth");
drivers/net/ethernet/samsung/sxgbe/sxgbe_platform.c: plat->bus_id =
of_alias_get_id(np, "ethernet");
drivers/net/ethernet/stmicro/stmmac/dwmac-loongson.c: plat->bus_id =
of_alias_get_id(np, "ethernet");
drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c: plat->bus_id =
of_alias_get_id(np, "ethernet");
There were discussions about using that alias to name ethernet network
devices in the past (cannot quite point to the thread), the current
consensus appears to be that if you use the "label" property (which was
primed by DSA) then your network device will follow that name, still not
something the networking stack does for you within the guts of
register_netdev().
--
Florian
More information about the U-Boot
mailing list