Function et_register

freebsd/kern/kern_et.c:55–100

* Register a new event timer hardware. */

 * Register a new event timer hardware.
 */
int
et_register(struct eventtimer *et)
{
	struct eventtimer *tmp, *next;

	if (et->et_quality >= 0 || bootverbose) {
		if (et->et_frequency == 0) {
			printf("Event timer \"%s\" quality %d\n",
			    et->et_name, et->et_quality);
		} else {
			printf("Event timer \"%s\" "
			    "frequency %ju Hz quality %d\n",
			    et->et_name, (uintmax_t)et->et_frequency,
			    et->et_quality);
		}
	}
	KASSERT(et->et_start, ("et_register: timer has no start function"));
	et->et_sysctl = SYSCTL_ADD_NODE_WITH_LABEL(NULL,
	    SYSCTL_STATIC_CHILDREN(_kern_eventtimer_et), OID_AUTO, et->et_name,
	    CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
	    "event timer description", "eventtimer");
	SYSCTL_ADD_INT(NULL, SYSCTL_CHILDREN(et->et_sysctl), OID_AUTO,
	    "flags", CTLFLAG_RD, &(et->et_flags), 0,
	    "Event timer capabilities");
	SYSCTL_ADD_UQUAD(NULL, SYSCTL_CHILDREN(et->et_sysctl), OID_AUTO,
	    "frequency", CTLFLAG_RD, &(et->et_frequency),
	    "Event timer base frequency");
	SYSCTL_ADD_INT(NULL, SYSCTL_CHILDREN(et->et_sysctl), OID_AUTO,
	    "quality", CTLFLAG_RD, &(et->et_quality), 0,
	    "Goodness of event timer");
	ET_LOCK();
	if (SLIST_EMPTY(&eventtimers) ||
	    SLIST_FIRST(&eventtimers)->et_quality < et->et_quality) {
		SLIST_INSERT_HEAD(&eventtimers, et, et_all);
	} else {
		SLIST_FOREACH(tmp, &eventtimers, et_all) {
			next = SLIST_NEXT(tmp, et_all);
			if (next == NULL || next->et_quality < et->et_quality) {
				SLIST_INSERT_AFTER(tmp, et, et_all);
				break;
			}
		}
	}
	ET_UNLOCK();
	return (0);
}

/*
 * Deregister event timer hardware.