Re: [PATCH 1/2] mtd: spi-nor: sst: register SFDP region into NVMEM framework to read MAC Address

On 05/03/2025 at 15:31:33 +0530, Manikandan Muralidharan [off-list ref] wrote:

From: Varshini Rajendran <redacted>

EUI identifier and the MAC Address of the Ethernet Interface is stored
after the SFDP table of contents starting at address 0x260 in the
QSPI memory.
Register the entire SFDP region read by the spi-nor (nor->sfdp) into the
NVMEM framework and read the MAC Address when requested using the nvmem
properties in the DT by the net drivers.

In kernel the Ethernet MAC address relied on U-Boot env variables or
generated a random address, which posed challenges for boards without
on-board EEPROMs or with multiple Ethernet ports.
This change ensures consistent and reliable MAC address retrieval from QSPI,
benefiting boards like the sama5d29 curiosity and sam9x75 curiosity.

Do you mean spi-nor have a programmable area in their SFDP table? Isn't
this supposed to be a read-only area written once in factory?

I am not a big fan of exposing the whole SFDP area. I would suggest to
expose just the MAC address. You can make use of nvmem layout drivers if
that is needed.

Thanks,
Miquèl