Adding an Interrupt Handler

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 either include a high-level interrupt or fail the attach.

In the following example, a high-level interrupt is required but not provided by the driver. Consequently, the driver fails the attach.

	if (ddi_intr_hilevel(dip, 0) != 0) {
 		return (DDI_FAILURE);
 	}

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);
 	}