Thank you for contacting the Intel Communities.
This is the information available to the public: http://download.intel.com/newsroom/kits/atom/comms/pdfs/Intel_XMM_6255_product_brief.pdf
Also, there is a website where you can enroll to become a developer, to get more information and benefits from the program.
First access the website Intel® Embedded Design Center Contact and Support, go to Register as an Intel Embedded Developer.
Once that is done, you should apply for extras with privileged access to the Intel® EDC¹
By doing this you could get more information regarding this product and other technologies that Intel has.
This would also apply for the thread Intel XMM 7260 documentation