USB device connection issue on STM32MP151 custom board (EHCI timeout after PORT_RESET)

[kiichi]

Hello,
We are using an STM32MP151 on a custom board and facing an issue with USB device connection via EHCI (USB 2.0).
Problem description:

After issuing a PORT_RESET, the J/K chirp sequence does not start, and we get a timeout error.
If we disable EHCI and use OHCI, the device connects successfully.

Hardware difference compared to evaluation board:

Our design does not include a high-speed hub IC.
The USB Type-A connector is directly connected to the STM32MP151.

Questions:

Has anyone experienced similar behavior on a custom board without a high-speed hub?
Are there any hardware design requirements (VBUS, RREF resistor, clock quality) or Device Tree settings that need to be adjusted for EHCI operation?
Any recommended debug steps for this issue?

Additional info:

Kernel logs show timeout after PORT_RESET.
OHCI works fine for full-speed devices.

Any guidance or suggestions would be greatly appreciated.
Thank you!

[kiichi]

Hello,
I have attached the oscilloscope waveform. After issuing PORT_RESET, the J/K toggling does not start, and the process ends with a timeout error. I would like to investigate the possible cause of this behavior.

I have checked the clock settings using clk_summary, and the 48 MHz and other related clocks appear to be correct.
For reference, the evaluation board uses a 24 MHz HSE, while our custom board uses a 30 MHz HSE.

If anyone has advice or suggestions on what I should look into next, I would greatly appreciate it.

Thank you.