Change buswidth on the hps2fpga bridge

Hi,

I am trying to enable the hps2fpga bridge using 64 bits instead of 32 bits,

From qsys and fpga side everything seems fine but i am not sure what i have to do on linux side in order to really enable the 64 bit.

Do i have to change the device tree? Because in my current device tree i couldn't find an entry for the bus-width.

Can anyone help?