Renesas µPD720201 performance problem

I need four usb3.0 ports on BPI-R64. So I use Renesas µPD720201 convert CN25/CN8 pcie to four usb3.0 ports.

But, it seems the usb3.0 port speed not good. Here is the test case: R64 --> CN25/CN8 --> µPD720201 --> USB3.0 --> AX88179 -->RJ45–>PC. PC run iperf3 server, and R64 run iperf3 client. Download speed only 500Mbps, upload speed only 700Mbps. When run the iperf3 test, the softirq consumer too many cpu. image

I run the test with openwrt, kernel 4.19. I have apply the pci interrupt patch and pci controller splitting from @frank-w, and apply the “pcie msi irq clear” patch from

Any ideas? Thanks.

I would try a newer kernel as 4.19 had only very basic support. In 5.15 you need only dts patch for pcie splitting,or just use my 5.15-main branch