Function cpufreq_add_levels

freebsd/kern/kern_cpu.c:569–630

* Either directly obtain settings from the cpufreq driver, or build a list of * relative settings to be integrated later against an absolute max. */

 * relative settings to be integrated later against an absolute max.
 */
static int
cpufreq_add_levels(device_t cf_dev, struct cf_setting_lst *rel_sets)
{
	struct cf_setting_array *set_arr;
	struct cf_setting *sets;
	device_t dev;
	struct cpufreq_softc *sc;
	int type, set_count, error;

	sc = device_get_softc(cf_dev);
	dev = sc->cf_drv_dev;

	/* Skip devices that aren't ready. */
	if (!device_is_attached(cf_dev))
		return (0);

	/*
	 * Get settings, skipping drivers that offer no settings or
	 * provide settings for informational purposes only.
	 */
	error = CPUFREQ_DRV_TYPE(dev, &type);
	if (error != 0 || (type & CPUFREQ_FLAG_INFO_ONLY)) {
		if (error == 0) {
			CF_DEBUG("skipping info-only driver %s\n",
			    device_get_nameunit(cf_dev));
		}
		return (error);
	}

	sets = malloc(MAX_SETTINGS * sizeof(*sets), M_TEMP, M_NOWAIT);
	if (sets == NULL)
		return (ENOMEM);

	set_count = MAX_SETTINGS;
	error = CPUFREQ_DRV_SETTINGS(dev, sets, &set_count);
	if (error != 0 || set_count == 0)
		goto out;

	/* Add the settings to our absolute/relative lists. */
	switch (type & CPUFREQ_TYPE_MASK) {
	case CPUFREQ_TYPE_ABSOLUTE:
		error = cpufreq_insert_abs(sc, sets, set_count);
		break;
	case CPUFREQ_TYPE_RELATIVE:
		CF_DEBUG("adding %d relative settings\n", set_count);
		set_arr = malloc(sizeof(*set_arr), M_TEMP, M_NOWAIT);
		if (set_arr == NULL) {
			error = ENOMEM;
			goto out;
		}
		bcopy(sets, set_arr->sets, set_count * sizeof(*sets));
		set_arr->count = set_count;
		TAILQ_INSERT_TAIL(rel_sets, set_arr, link);
		break;
	default:
		error = EINVAL;
	}