But I could not find any info on official AMD site. Since we are planning to develop our own OS, there a lot of crusial information in datasheet for us.
I would open an AMD EMAIL SUPPORT Ticket and see if they will direct you to where you can download the information you need. You can open a ticket from here : Email Form .
ryzen_master, try here. I would also pursue eclataci's suggestion. When I tried to get some documents some months ago I was told they were still under NDA. You may have to enter one with AMD. Good luck and enjoy, John.