static int __init bcm2835_timer_init()

in bcm2835_timer.c [69:135]

• 54 lines of code
• 6 McCabe index (conditional complexity)

static int __init bcm2835_timer_init(struct device_node *node)
{
	void __iomem *base;
	u32 freq;
	int irq, ret;
	struct bcm2835_timer *timer;

	base = of_iomap(node, 0);
	if (!base) {
		pr_err("Can't remap registers\n");
		return -ENXIO;
	}

	ret = of_property_read_u32(node, "clock-frequency", &freq);
	if (ret) {
		pr_err("Can't read clock-frequency\n");
		goto err_iounmap;
	}

	system_clock = base + REG_COUNTER_LO;
	sched_clock_register(bcm2835_sched_read, 32, freq);

	clocksource_mmio_init(base + REG_COUNTER_LO, node->name,
		freq, 300, 32, clocksource_mmio_readl_up);

	irq = irq_of_parse_and_map(node, DEFAULT_TIMER);
	if (irq <= 0) {
		pr_err("Can't parse IRQ\n");
		ret = -EINVAL;
		goto err_iounmap;
	}

	timer = kzalloc(sizeof(*timer), GFP_KERNEL);
	if (!timer) {
		ret = -ENOMEM;
		goto err_iounmap;
	}

	timer->control = base + REG_CONTROL;
	timer->compare = base + REG_COMPARE(DEFAULT_TIMER);
	timer->match_mask = BIT(DEFAULT_TIMER);
	timer->evt.name = node->name;
	timer->evt.rating = 300;
	timer->evt.features = CLOCK_EVT_FEAT_ONESHOT;
	timer->evt.set_next_event = bcm2835_time_set_next_event;
	timer->evt.cpumask = cpumask_of(0);

	ret = request_irq(irq, bcm2835_time_interrupt, IRQF_TIMER | IRQF_SHARED,
			  node->name, timer);
	if (ret) {
		pr_err("Can't set up timer IRQ\n");
		goto err_timer_free;
	}

	clockevents_config_and_register(&timer->evt, freq, 0xf, 0xffffffff);

	pr_info("bcm2835: system timer (irq = %d)\n", irq);

	return 0;

err_timer_free:
	kfree(timer);

err_iounmap:
	iounmap(base);
	return ret;
}