USBF_REG_EP0_STATUS
ep0->status = usbf_ep_reg_readl(ep0, USBF_REG_EP0_STATUS);
usbf_ep_reg_writel(ep0, USBF_REG_EP0_STATUS, ~ep0->status);
usbf_ep_reg_readl(ep0, USBF_REG_EP0_STATUS));
ret = readl_poll_timeout_atomic(ep0->regs + USBF_REG_EP0_STATUS, sts,