Re: [PATCH 3/4] nvmem: layouts: Add Rockchip OTP CPUID layout driver

On 01/09/2026 at 19:33:13 +04, Alexey Charkov [off-list ref] wrote:

Rockchip SoCs customarily use the CPU ID programmed into their on-chip OTP
memory to derive stable Ethernet MAC addresses even when a board doesn't
otherwise have dedicated storage for those. The derivation depends on the
particular bootloader implementation (e.g. it is done by upstream U-Boot,
which patches the derived MAC addresses at runtime into the device tree it
hands to the kernel). Using less featureful bootloaders, such as direct
boot to Linux from SPL, leaves the kernel with only a random MAC address
instead, even though everything required for the derivation is equally
available to Linux as it is to U-Boot.

Reproduce the same derivation in the kernel and expose the result as an
nvmem cell named "mac-address", so that of_get_mac_address() picks it up
through its standard nvmem fallback. The address index comes from the DT
phandle argument, which lets both interfaces of a dual Ethernet board
share a single cell.

Enable the layout by default on Rockchip, as consumers of its cells would
otherwise defer their probe indefinitely.

Signed-off-by: Alexey Charkov <redacted>

Quick review on my side, looks good to me.

Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>