PCI write from end device

Hi,

I have a design with a Stratix 5, a Qsys system with a PCI express device.

For some reasons, we don't want to read on this device, but we want it to write to the CPU. We want the CPU to ask this device to update a memory location.

I don't know how I can initiate a write from my device. Do I have to use the CRA port? Is there already a Qsys module that enables that?

Best regards,

Jerome