How to use the device tree

[Renaud Barbier]

I was wondering how I could use the device tree to locate a board MAC 
address
in U-boot. The MAC address could be located in flash or I2C depending on 
the board.
Depending of  information like storage type, base address, offset I 
would like to find the MAC address.

Could somebody give me ideas?

Should I define a node entry specifically to find the MAC address?
Or should i define variables in the "chosen" that would help me find the 
mac?

thanks.