Re: [PATCH 3/3] ARM: boards: Add MyirTech MYD-YA15XC-T development board support

[Ahmad Fatoum <a.fatoum@pengutronix.de>]

On 31.08.23 11:41, Alexander Shiyan wrote:
>>> +struct id_eeprom {
>>> +     u8 hrcw_primary[0x10];
>>> +     u8 pn[64];
>>> +     u8 sn[64];
>>> +     u8 mac0[6];
>>> +     u8 mac1[6];
>>> +} __packed;
>>
>> You could describe this as nvmem-cells in the DT and you'd automatically
>> get the MAC addresses assigned.
> ...
>>> +     if (!is_valid_ether_addr(eeprom.mac0)) {
>>> +             int i, j;
>>> +
>>> +             /* Make fixed MAC-address based on serial number */
>>> +             memcpy(eeprom.mac0, str, sizeof(eeprom.mac0));
>>> +             for (i = sizeof(eeprom.mac0); i < len; i++)
>>> +                     for (j = 0; j < sizeof(eeprom.mac0); j++)
>>> +                             eeprom.mac0[j] ^= str[i];
>>> +     }
>>> +
>>> +     eth_register_ethaddr(0, eeprom.mac0);
>> You could check if the nvmem cell exists and only do the fixup
>> if it doesn't. Check Marco's recent Debix patches for an example
>> of how to call nvmem from board code.
> 
> I can't find a way to know if an MAC address that was automatically
> assigned via nvmem is valid.
> So in this case we always need to use eth_register_ethaddr() manually?

You could fetch the nvmem cell and verify it yourself before MAC address
is assigned. What I'd like to have eventually is a Kconfig option to
generate a MAC address out of the serial number automatically if one was
set and if not, only then fall back to randomization.

I even have patches somewhere. Let me check.

Cheers,
Ahmad

> 

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