static int smmu_pmu_event_init()

in arm_smmuv3_pmu.c [364:423]

• 42 lines of code
• 12 McCabe index (conditional complexity)

static int smmu_pmu_event_init(struct perf_event *event)
{
	struct hw_perf_event *hwc = &event->hw;
	struct smmu_pmu *smmu_pmu = to_smmu_pmu(event->pmu);
	struct device *dev = smmu_pmu->dev;
	struct perf_event *sibling;
	int group_num_events = 1;
	u16 event_id;

	if (event->attr.type != event->pmu->type)
		return -ENOENT;

	if (hwc->sample_period) {
		dev_dbg(dev, "Sampling not supported\n");
		return -EOPNOTSUPP;
	}

	if (event->cpu < 0) {
		dev_dbg(dev, "Per-task mode not supported\n");
		return -EOPNOTSUPP;
	}

	/* Verify specified event is supported on this PMU */
	event_id = get_event(event);
	if (event_id < SMMU_PMCG_ARCH_MAX_EVENTS &&
	    (!test_bit(event_id, smmu_pmu->supported_events))) {
		dev_dbg(dev, "Invalid event %d for this PMU\n", event_id);
		return -EINVAL;
	}

	/* Don't allow groups with mixed PMUs, except for s/w events */
	if (!is_software_event(event->group_leader)) {
		if (!smmu_pmu_events_compatible(event->group_leader, event))
			return -EINVAL;

		if (++group_num_events > smmu_pmu->num_counters)
			return -EINVAL;
	}

	for_each_sibling_event(sibling, event->group_leader) {
		if (is_software_event(sibling))
			continue;

		if (!smmu_pmu_events_compatible(sibling, event))
			return -EINVAL;

		if (++group_num_events > smmu_pmu->num_counters)
			return -EINVAL;
	}

	hwc->idx = -1;

	/*
	 * Ensure all events are on the same cpu so all events are in the
	 * same cpu context, to avoid races on pmu_enable etc.
	 */
	event->cpu = smmu_pmu->on_cpu;

	return 0;
}