[coreboot] sources about coreboot devicetree

Hi
I want to fully understand the structure of coreboot devicetree and to be able to make chenges, but I couldn't find much resources, only two pages helped me some.. my first question is about resources to learn this..

My second, there are other videos and things talking about devicetree in linux (which I know is different from the corebootie one), do you think reading these ones is helpful for me? or for example learning ASL helps? I'm a newbie in the hardware...