[U-Boot] how to enable data cache on at91rm9200?

Hi,

how would I enable the data cache for an at91rm9200? (ARM920T)

Can someone point me in the right direction, or pass me a patch for any version of U-Boot?

The aim is to improve the boot time as suggested here: http://elinux.org/Boot_Time#Boot_time_check_list

Aras