See http://seabios.org/Debugging

I couldn't add the physical EHCI controller to qemu using pass through. how to do that?

So, you are using coreboot+seabios on vmware and coreboot+seabios on
real hardware as well?

no, i have developed a boot loader and for usb detection and enumeration i have used the seabios source base and i test this bootloader with vmware and real hardware