static int scmi_cpufreq_init()

in scmi-cpufreq.c [121:235]

• 75 lines of code
• 13 McCabe index (conditional complexity)

static int scmi_cpufreq_init(struct cpufreq_policy *policy)
{
	int ret, nr_opp;
	unsigned int latency;
	struct device *cpu_dev;
	struct scmi_data *priv;
	struct cpufreq_frequency_table *freq_table;

	cpu_dev = get_cpu_device(policy->cpu);
	if (!cpu_dev) {
		pr_err("failed to get cpu%d device\n", policy->cpu);
		return -ENODEV;
	}

	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
	if (!priv)
		return -ENOMEM;

	if (!zalloc_cpumask_var(&priv->opp_shared_cpus, GFP_KERNEL)) {
		ret = -ENOMEM;
		goto out_free_priv;
	}

	/* Obtain CPUs that share SCMI performance controls */
	ret = scmi_get_sharing_cpus(cpu_dev, policy->cpus);
	if (ret) {
		dev_warn(cpu_dev, "failed to get sharing cpumask\n");
		goto out_free_cpumask;
	}

	/*
	 * Obtain CPUs that share performance levels.
	 * The OPP 'sharing cpus' info may come from DT through an empty opp
	 * table and opp-shared.
	 */
	ret = dev_pm_opp_of_get_sharing_cpus(cpu_dev, priv->opp_shared_cpus);
	if (ret || !cpumask_weight(priv->opp_shared_cpus)) {
		/*
		 * Either opp-table is not set or no opp-shared was found.
		 * Use the CPU mask from SCMI to designate CPUs sharing an OPP
		 * table.
		 */
		cpumask_copy(priv->opp_shared_cpus, policy->cpus);
	}

	 /*
	  * A previous CPU may have marked OPPs as shared for a few CPUs, based on
	  * what OPP core provided. If the current CPU is part of those few, then
	  * there is no need to add OPPs again.
	  */
	nr_opp = dev_pm_opp_get_opp_count(cpu_dev);
	if (nr_opp <= 0) {
		ret = perf_ops->device_opps_add(ph, cpu_dev);
		if (ret) {
			dev_warn(cpu_dev, "failed to add opps to the device\n");
			goto out_free_cpumask;
		}

		nr_opp = dev_pm_opp_get_opp_count(cpu_dev);
		if (nr_opp <= 0) {
			dev_err(cpu_dev, "%s: No OPPs for this device: %d\n",
				__func__, nr_opp);

			ret = -ENODEV;
			goto out_free_opp;
		}

		ret = dev_pm_opp_set_sharing_cpus(cpu_dev, priv->opp_shared_cpus);
		if (ret) {
			dev_err(cpu_dev, "%s: failed to mark OPPs as shared: %d\n",
				__func__, ret);

			goto out_free_opp;
		}

		priv->nr_opp = nr_opp;
	}

	ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table);
	if (ret) {
		dev_err(cpu_dev, "failed to init cpufreq table: %d\n", ret);
		goto out_free_opp;
	}

	priv->cpu_dev = cpu_dev;
	priv->domain_id = perf_ops->device_domain_id(cpu_dev);

	policy->driver_data = priv;
	policy->freq_table = freq_table;

	/* SCMI allows DVFS request for any domain from any CPU */
	policy->dvfs_possible_from_any_cpu = true;

	latency = perf_ops->transition_latency_get(ph, cpu_dev);
	if (!latency)
		latency = CPUFREQ_ETERNAL;

	policy->cpuinfo.transition_latency = latency;

	policy->fast_switch_possible =
		perf_ops->fast_switch_possible(ph, cpu_dev);

	return 0;

out_free_opp:
	dev_pm_opp_remove_all_dynamic(cpu_dev);

out_free_cpumask:
	free_cpumask_var(priv->opp_shared_cpus);

out_free_priv:
	kfree(priv);

	return ret;
}