DS5 FVP frequency ?

Which FVP are you using?

Any frequencies used would depend on the FVP used rather than DS-5. For example, the frequencies listed in Fixed Virtual Platforms FVP Reference Guide at

infocenter.arm.com/.../index.html

state:

"5.3 VE - clock and timer

This section describes the frequencies of the clock and timer.

Cluster clk_in frequency parameter
100MHz.
GenericTimer base_frequency parameter
100MHz."

You will need to refer to your FVP documentation for further information.