[PATCH net] net: stmmac: platform: guarantee uniqueness of bus_id

[Abhishek Chauhan (ABC)]

On 5/26/2025 1:26 PM, Paolo Abeni wrote:
> On 5/21/25 5:21 PM, Quentin Schulz wrote:
>> From: Quentin Schulz <quentin.schulz at cherry.de>
>>
>> bus_id is currently derived from the ethernetX alias. If one is missing
>> for the device, 0 is used. If ethernet0 points to another stmmac device
>> or if there are 2+ stmmac devices without an ethernet alias, then bus_id
>> will be 0 for all of those.
>>
>> This is an issue because the bus_id is used to generate the mdio bus id
>> (new_bus->id in drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c
>> stmmac_mdio_register) and this needs to be unique.
>>
>> This allows to avoid needing to define ethernet aliases for devices with
>> multiple stmmac controllers (such as the Rockchip RK3588) for multiple
>> stmmac devices to probe properly.
>>
>> Obviously, the bus_id isn't guaranteed to be stable across reboots if no
>> alias is set for the device but that is easily fixed by simply adding an
>> alias if this is desired.
>>
>> Signed-off-by: Quentin Schulz <quentin.schulz at cherry.de>
> 
> I think no need to CC stable here, but you need to provide a suitable
> fixes tag, thanks!
> 
Quentin to make your life easy. 
It fixes this patch 
https://lore.kernel.org/lkml/1372930541-19409-1-git-send-email-srinivas.kandagatla@st.com/
dt:net:stmmac: Add support to dwmac version 3.610 and 3.710
It goes back in time to 2013 when this bus_id was introduced through dts

> Paolo
> 
>