static int arm_ccn_pmu_event_alloc()

in arm-ccn.c [631:687]

• 45 lines of code
• 8 McCabe index (conditional complexity)

static int arm_ccn_pmu_event_alloc(struct perf_event *event)
{
	struct arm_ccn *ccn = pmu_to_arm_ccn(event->pmu);
	struct hw_perf_event *hw = &event->hw;
	u32 node_xp, type, event_id;
	struct arm_ccn_component *source;
	int bit;

	node_xp = CCN_CONFIG_NODE(event->attr.config);
	type = CCN_CONFIG_TYPE(event->attr.config);
	event_id = CCN_CONFIG_EVENT(event->attr.config);

	/* Allocate the cycle counter */
	if (type == CCN_TYPE_CYCLES) {
		if (test_and_set_bit(CCN_IDX_PMU_CYCLE_COUNTER,
				ccn->dt.pmu_counters_mask))
			return -EAGAIN;

		hw->idx = CCN_IDX_PMU_CYCLE_COUNTER;
		ccn->dt.pmu_counters[CCN_IDX_PMU_CYCLE_COUNTER].event = event;

		return 0;
	}

	/* Allocate an event counter */
	hw->idx = arm_ccn_pmu_alloc_bit(ccn->dt.pmu_counters_mask,
			CCN_NUM_PMU_EVENT_COUNTERS);
	if (hw->idx < 0) {
		dev_dbg(ccn->dev, "No more counters available!\n");
		return -EAGAIN;
	}

	if (type == CCN_TYPE_XP)
		source = &ccn->xp[node_xp];
	else
		source = &ccn->node[node_xp];
	ccn->dt.pmu_counters[hw->idx].source = source;

	/* Allocate an event source or a watchpoint */
	if (type == CCN_TYPE_XP && event_id == CCN_EVENT_WATCHPOINT)
		bit = arm_ccn_pmu_alloc_bit(source->xp.dt_cmp_mask,
				CCN_NUM_XP_WATCHPOINTS);
	else
		bit = arm_ccn_pmu_alloc_bit(source->pmu_events_mask,
				CCN_NUM_PMU_EVENTS);
	if (bit < 0) {
		dev_dbg(ccn->dev, "No more event sources/watchpoints on node/XP %d!\n",
				node_xp);
		clear_bit(hw->idx, ccn->dt.pmu_counters_mask);
		return -EAGAIN;
	}
	hw->config_base = bit;

	ccn->dt.pmu_counters[hw->idx].event = event;

	return 0;
}