static int psci_idle_init_cpu()

in cpuidle-psci.c [278:350]

• 44 lines of code
• 10 McCabe index (conditional complexity)

static int psci_idle_init_cpu(struct device *dev, int cpu)
{
	struct cpuidle_driver *drv;
	struct device_node *cpu_node;
	const char *enable_method;
	int ret = 0;

	cpu_node = of_cpu_device_node_get(cpu);
	if (!cpu_node)
		return -ENODEV;

	/*
	 * Check whether the enable-method for the cpu is PSCI, fail
	 * if it is not.
	 */
	enable_method = of_get_property(cpu_node, "enable-method", NULL);
	if (!enable_method || (strcmp(enable_method, "psci")))
		ret = -ENODEV;

	of_node_put(cpu_node);
	if (ret)
		return ret;

	drv = devm_kzalloc(dev, sizeof(*drv), GFP_KERNEL);
	if (!drv)
		return -ENOMEM;

	drv->name = "psci_idle";
	drv->owner = THIS_MODULE;
	drv->cpumask = (struct cpumask *)cpumask_of(cpu);

	/*
	 * PSCI idle states relies on architectural WFI to be represented as
	 * state index 0.
	 */
	drv->states[0].enter = psci_enter_idle_state;
	drv->states[0].exit_latency = 1;
	drv->states[0].target_residency = 1;
	drv->states[0].power_usage = UINT_MAX;
	strcpy(drv->states[0].name, "WFI");
	strcpy(drv->states[0].desc, "ARM WFI");

	/*
	 * If no DT idle states are detected (ret == 0) let the driver
	 * initialization fail accordingly since there is no reason to
	 * initialize the idle driver if only wfi is supported, the
	 * default archictectural back-end already executes wfi
	 * on idle entry.
	 */
	ret = dt_init_idle_driver(drv, psci_idle_state_match, 1);
	if (ret <= 0)
		return ret ? : -ENODEV;

	/*
	 * Initialize PSCI idle states.
	 */
	ret = psci_cpu_init_idle(dev, drv, cpu, ret);
	if (ret) {
		pr_err("CPU %d failed to PSCI idle\n", cpu);
		return ret;
	}

	ret = cpuidle_register(drv, NULL);
	if (ret)
		goto deinit;

	cpuidle_cooling_register(drv);

	return 0;
deinit:
	psci_cpu_deinit_idle(cpu);
	return ret;
}