GR_EPCTRL_EH
seq_printf(seq, " halted: %d\n", !!(epctrl & GR_EPCTRL_EH));
gr_write32(&ep->regs->epctrl, epctrl | GR_EPCTRL_EH);
gr_write32(&ep->regs->epctrl, epctrl & ~GR_EPCTRL_EH);
halted = gr_read32(&ep->regs->epctrl) & GR_EPCTRL_EH;