DELAYSeconds not really 1s delay

The delay functions in plat_delay.h don't seem to delay accurately.  E.g. I need a 1s delay, so I call:

void DELAYSeconds( unsigned int duration) with duration = 1.  However it appears to be much shorter than 1s.

Is there some way to tune this function so it is more accurate?

I am using the AM3359 on the ICE_V2 eval board.