USB 3 devices do not work with RFSoC 4x2 USB 3.0 Host

[hecrabbs]

The 2-port USB 3.0 host on the RFSoC 4x2 does not work with USB 3.0 devices when running the base overlay. USB 2 devices will connect properly, and when inserting a USB 3 flash drive partially it will be detected and work as USB 2. However, inserting the same USB 3 flash drive correctly shows no changes in the dmesg or lsusb output.

[vdahle]

I am also struggling with the USB hosts not working with USB 3.0 on the RFSoC4x2 board.
As far as I can see there are drivers for 3.0 existing (cat /sys/bus/usb/devices/usb2/version gives the result 3.0), but something is broken with the connection between the kernel and the physical component.

A plausible candidate is the USB clock in the device tree, which uses 26MHz when both the RFSoC 4x2 Reference Manual and the RFSoC4x2 board files claims a 100 MHz clock.

RFSoC-PYNQ/boards/RFSoC4x2/petalinux_bsp/meta-user/recipes-bsp/device-tree/files/system-user.dtsi

Line 19 in 5e09835

clock-frequency = <26000000>;

I have not yet had (and is unsure when/if I'll get) the opportunity actually test a fixed clock in a recompiled image, so it might not be the only error. But if anyone (ideally the repo maintainers) have the possibility to do so it would be amazing.

[pdaderko]

I was having an issue with the USB 3.0 on my board and did a little bit of digging. The issue I'm having looks to be related to PYNQ 3.1.1 only ( #59 ), so different than this one.

This issue looks like it may be related to the discussion here: https://discuss.pynq.io/t/rfsoc-4x2-usb-host-and-usb-device-not-working/6090

Just wanted to add a little bit of information from my research and board specifics. That thread discussed USB5742 A001 vs. B101. I got a new board a couple months ago. I believe it was from a new build, since they said there was a lead time waiting for the build to complete. My board has a USB5742 B101 chip, but works fine at USB 3.0 with PYNQ 2.7 and 3.0.1 images.

I suspect that problem, and possibly the one discussed here is related to a PCB layout issue. I happened to have an old schematic (12/17/2021, V2I1) that I had downloaded several years ago, and comparing that to the one that's available for download now (5/23/2024, V3I1), a close look at the USB 3.0 Host sheet will show that V3I1 corrected an error, where they had USB1_US_TX to USB3UP_TX and USB1_US_RX to USB3UP_RX. These should be connected Tx to Rx and vice versa. Connected as-is, the USB hub won't work at USB 3.0.

Looking at my board, I didn't see a V2I1 or V3I1 anywhere, but there is "REV C" text on the back. Hoping to cross-reference this, I downloaded the Gerbers from the RealDigital site. It looks like they're still the old V2I1 ones from 2023... but looking at RFSoC_4X2_Gen3_PCB_V2I1.GBO , I see the text is REV B. So it seems plausible that V3I1 would be REV C. And if the fixed schematics are from 2024, it seems likely that the issues discussed in that thread from 2023 would be related to that... and it may have taken a while before they had REV C built/tested and sold off all REV B stock.

So I'd check what the board revision is, and if it's REV B, it may need a hardware mod. If you have the proper tools/skills, shouldn't be too difficult to rework this to swap the pairs (maybe won't meet USB spec 100%, but I've gotten away with much more worse mods).

[jogomojo]

PR #60 should fix the USB3 issue on the RFSoC4x2. I'll merge it once I've validated it against a built image, and the fix will be included in the next PYNQ SD card image release. In the meantime, you can build a new image yourself using the standard sdbuild flow.

[pdaderko]

Interesting - are you suggesting that the PCB layout itself was actually correct, but the old V2I1 schematics were just incorrect? Or do you think an old board would need your fix, plus a hardware mod? We bought a couple boards several years ago, but never tried USB until this newest board.