You can create 4 UDP streams or MAC level stream (2x2pinpong) in time to send to the PC.
MAC is less costly in overhead, but at this level in a modern OS you need to have the skill to work, but UDP is trivial.
It will obviously be faster than USB 2.0.
No, w5500 maxes out at 100 Mbit/s (100Base-T), whereas USB 2.0 High Speed maxes out at 480 Mbit/s. What I listed w/Teensy 4.x is practical sustained bandwidth with no losses when the MCU generates the data, not theoretical maximum bandwidth or a special case.
USB 3 and gigabit ethernet are a separate matter. The nearby
GigE Micros thread discusses some of those options.
With CYUSB3, the only problem for
me is that the GPIF II Designer is not available for Linux, and reportedly does not run (well enough to be used) under Wine either. I have no Windows licenses, so a VM is pretty much out as well. And I don't want to misuse MS licenses (say, on their development VM images), so CYUSB3's GPIF II is basically out for me.
After all, you can use two separate MCUs for MOSI and MOSO.
Makes combining the streams into a coherent stream very difficult.
Yes, [CYUSB3]'s great value for money, but also (at least) a factor of 2 too slow for a general-purpose logic analyzer in this situation, as I explained earlier.
If you have Windows, you could register at Infineon, download the EZ-USB FX3 SDK, and run the GPIF II Designer to see if you can use the sniffed SCK as a trigger for latching the two inputs; probably will have to latch a full 8-bit byte, but that's okay; there's plenty of bandwidth. I have registered (I have an EZ-USB FX2), but not being able to run the GPIF II Designer as it is Windows-only, I cannot verify this. Based on the general descriptions, I do believe it is possible; GPIF and GPIF II are basically limited state machines with several control inputs, it's just that Cypress/Infineon for some reason really don't want to tell users how it is controlled, and only provide a Windows GUI tool to configure it. It even uses a separate 8k RAM for its state machine description, I understand.