uboot and bsd on BeagleBone Black

[eros.wade]

HI all 

         I've succeed complied uboot and freebsd on BeagleBone Black with
crochet. 

         But I don't know how bsd can run on beaglebone black. 

         I know that uboot for BBB contains thouse hardware info (PINS,
GPIO, SPI etc). 

         How can bsd get thouse infos from uboot. 

         Or uboot just load BSD, but where is the hardware infos on bsd src
tree?

eros