Re: [PATCH net-next] dt-bindings: net: xilinx: document xilinx emaclite driver binding

[Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>]

On 31/05/2022 20:19, Radhey Shyam Pandey wrote:
>> -----Original Message-----
>> From: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
>> Sent: Tuesday, May 31, 2022 12:40 AM
>> To: Radhey Shyam Pandey <radheys@xilinx.com>; Radhey Shyam Pandey
>> <radhey.shyam.pandey@amd.com>; davem@davemloft.net;
>> edumazet@google.com; kuba@kernel.org; pabeni@redhat.com;
>> robh+dt@kernel.org; krzysztof.kozlowski+dt@linaro.org;
>> harini.katakam@amd.com; michal.simek@amd.com
>> Cc: netdev@vger.kernel.org; devicetree@vger.kernel.org; linux-
>> kernel@vger.kernel.org; git@amd.com
>> Subject: Re: [PATCH net-next] dt-bindings: net: xilinx: document xilinx emaclite
>> driver binding
>>
>> On 30/05/2022 15:21, Radhey Shyam Pandey wrote:
>>>>
>>>>> +        local-mac-address = [00 0a 35 00 00 00];
>>>>
>>>> Each device should get it's own MAC address, right? I understand you
>>>> leave it for bootloader, then just fill it with 0.
>>>
>>> The emaclite driver uses of_get_ethdev_address() to get mac from DT.
>>> i.e  'local-mac-address' if present in DT it will be read and this MAC
>>> address is programmed in the MAC core. So I think it's ok to have a
>>> user defined mac-address (instead of 0s) here in DT example?
>>
>> And you want to program the same MAC address in every device in the world?
>> How would that work?
> 
> I agree, for most of practical usecases mac address will be set by bootloader[1].
> But just thinking for usecases where uboot can't read from non-volatile memory
> user are still provided with option to set local-mac-address in DT and let linux
> also configures it? Also see this in couple of other networking driver examples. 

Which is not necessarily correct approach
> 
> cdns,macb.yaml:  local-mac-address: true
> cdns,macb.yaml:            local-mac-address = [3a 0e 03 04 05 06];
> brcm,systemport.yaml:        local-mac-address = [ 00 11 22 33 44 55 ];

This brcm looks like an invalid MAC, so could be just placeholder.

> 
> In emaclite yaml - as it an example I will set it mac-address to 0 to align 
> with common usecase.  local-mac-address = [00 00 00 00 00 00]
> 

Thanks.


Best regards,
Krzysztof