ixp12x0_intr_establish
ixp12x0_intr_establish(IXPPCI_INTR_T1, IPL_CLOCK, ixpclk_intr, NULL);
void *ixp12x0_intr_establish(int irq, int ipl, int (*)(void *), void *);
return (ixp12x0_intr_establish(ih, ipl, func, arg));
ixp12x0_intr_establish(IXP12X0_INTR_UART, IPL_SERIAL, ixpcomintr, sc);