VIO_DR_STATE_RXREG
if (vio->dr_state & VIO_DR_STATE_RXREG)
VIO_DR_STATE_RXREG);
!(vio->dr_state & VIO_DR_STATE_RXREG))
if (vio->dr_state & VIO_DR_STATE_RXREG)
vio->dr_state |= VIO_DR_STATE_RXREG;
vio->dr_state &= ~VIO_DR_STATE_RXREG;
BUG_ON(!(vio->dr_state & VIO_DR_STATE_RXREG));