static int __init clint_timer_init_dt()

in timer-clint.c [147:241]

• 70 lines of code
• 14 McCabe index (conditional complexity)

static int __init clint_timer_init_dt(struct device_node *np)
{
	int rc;
	u32 i, nr_irqs;
	void __iomem *base;
	struct of_phandle_args oirq;

	/*
	 * Ensure that CLINT device interrupts are either RV_IRQ_TIMER or
	 * RV_IRQ_SOFT. If it's anything else then we ignore the device.
	 */
	nr_irqs = of_irq_count(np);
	for (i = 0; i < nr_irqs; i++) {
		if (of_irq_parse_one(np, i, &oirq)) {
			pr_err("%pOFP: failed to parse irq %d.\n", np, i);
			continue;
		}

		if ((oirq.args_count != 1) ||
		    (oirq.args[0] != RV_IRQ_TIMER &&
		     oirq.args[0] != RV_IRQ_SOFT)) {
			pr_err("%pOFP: invalid irq %d (hwirq %d)\n",
			       np, i, oirq.args[0]);
			return -ENODEV;
		}

		/* Find parent irq domain and map timer irq */
		if (!clint_timer_irq &&
		    oirq.args[0] == RV_IRQ_TIMER &&
		    irq_find_host(oirq.np))
			clint_timer_irq = irq_of_parse_and_map(np, i);
	}

	/* If CLINT timer irq not found then fail */
	if (!clint_timer_irq) {
		pr_err("%pOFP: timer irq not found\n", np);
		return -ENODEV;
	}

	base = of_iomap(np, 0);
	if (!base) {
		pr_err("%pOFP: could not map registers\n", np);
		return -ENODEV;
	}

	clint_ipi_base = base + CLINT_IPI_OFF;
	clint_timer_cmp = base + CLINT_TIMER_CMP_OFF;
	clint_timer_val = base + CLINT_TIMER_VAL_OFF;
	clint_timer_freq = riscv_timebase;

#ifdef CONFIG_RISCV_M_MODE
	/*
	 * Yes, that's an odd naming scheme.  time_val is public, but hopefully
	 * will die in favor of something cleaner.
	 */
	clint_time_val = clint_timer_val;
#endif

	pr_info("%pOFP: timer running at %ld Hz\n", np, clint_timer_freq);

	rc = clocksource_register_hz(&clint_clocksource, clint_timer_freq);
	if (rc) {
		pr_err("%pOFP: clocksource register failed [%d]\n", np, rc);
		goto fail_iounmap;
	}

	sched_clock_register(clint_get_cycles64, 64, clint_timer_freq);

	rc = request_percpu_irq(clint_timer_irq, clint_timer_interrupt,
				 "clint-timer", &clint_clock_event);
	if (rc) {
		pr_err("registering percpu irq failed [%d]\n", rc);
		goto fail_iounmap;
	}

	rc = cpuhp_setup_state(CPUHP_AP_CLINT_TIMER_STARTING,
				"clockevents/clint/timer:starting",
				clint_timer_starting_cpu,
				clint_timer_dying_cpu);
	if (rc) {
		pr_err("%pOFP: cpuhp setup state failed [%d]\n", np, rc);
		goto fail_free_irq;
	}

	riscv_set_ipi_ops(&clint_ipi_ops);
	clint_clear_ipi();

	return 0;

fail_free_irq:
	free_irq(clint_timer_irq, &clint_clock_event);
fail_iounmap:
	iounmap(base);
	return rc;
}