Data transfer from hardware Modules to Nios

Thank you very much, actually you are right. I used timestamp timer and the total time for PIO reads was about 4us. So the problem is withe the cpu-w5300 communication. I used the drivers provided by Wiznet and the code isn't so complicated. On the other hand I am using generic tristate controller in QSYS to connect W5300 to Nios, so there is maybe a problem withe the configuration of tristate controller. Attached is the timing I used (I am running with a 140 Mhz clk). Do you have any experience with this?