Can you please elaborate your questions.
Sorry for the extreme delay.
With respect to your first question - USB_DMA[n]_CTL.EP is not an EP but rather used to select endpoint assignment for that that particular DMA channel. You can select one EP from possible 16 EP. For more information regarding USB_DMA[n]_CTL register please refer to Hardware Reference Manual.
Can you please explain in detail your "CSW packet not received problem" so that we can dig dipper to find the root cause?
When system read USB data for a long time, system can not receive CSW packet, but device convey CSW packet (Observe USB packet of device by USB EXPLORER)
Suspect that this problem is caused by busy DDR.
Do you still have the issue or has it been resolved?
I suspect the problem that DDR is busy .DDR is busy cause data loss.
Retrieving data ...