Dear Philippe De Muyter,
In message 20100220093717.GA9602@frolo.macqel you wrote:
Previously, the mac addresses were stored in the bd_info struct, but that has been removed, but alas not replaced by a common mechanism for all architectures.
Complain about this to the Linux architecture maintainers - there have been many and longf discussions about this before.
Today we consider the device tree to be the Right Thing (TM) to pass such information to the kernel, and more and more architectures use this method.
As long as it's not available for your architecture, the most straightforward way is to pass an "ethaddr=..." argument on the kernel command line. Drivers can pick it up easily there. Just don't expect that such Linux driver code will be accepted for mainline.