Read register or memory location

Is there an easy way to just read a memory location (or AM335x register) under Debian?

Not from u-boot but after fully booted?

If you just want to poke around, you can compile devmem2: http://free-electrons.com/pub/mirror/devmem2.c

If you want proper high speed access, see the devmem2 source, or do the equivalent in python, or any other language that supports mmap.