Adding an Interrupt Handler

The driver must first obtain the iblock cookie to initialize mutexes used in the driver handler. Only after those mutexes have been initialized can the interrupt handler be added.

    i = ddi_get_iblock_cookie(dip, 0, &isp->iblock_cookie};
     if (i != DDI_SUCCESS) {
         do error recovery
            return (DDI_FAILURE);
     }

     mutex_init(&isp->mutex, "isp_mutex", MUTEX_DRIVER,
         (void *)isp->iblock_cookie);
     i = ddi_add_intr(dip, 0, &isp->iblock_cookie,
         0, isp_intr, (caddr_t)isp);
     if (i != DDI_SUCCESS) {
         do error recovery
            return (DDI_FAILURE);
     }

The driver should determine if a high-level interrupt handler is required. If a high-level handler is required and the driver is not coded to provide one, the driver must be rewritten to include either a high-level interrupt or fail the attach. See "Handling High-Level Interrupts" for a description of high-level interrupt handling.