1 // SPDX-License-Identifier: GPL-2.0
3 * System Control and Power Interface (SCMI) based CPUFreq Interface driver
5 * Copyright (C) 2018 ARM Ltd.
6 * Sudeep Holla <sudeep.holla@arm.com>
9 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
11 #include <linux/cpu.h>
12 #include <linux/cpufreq.h>
13 #include <linux/cpumask.h>
14 #include <linux/energy_model.h>
15 #include <linux/export.h>
16 #include <linux/module.h>
17 #include <linux/pm_opp.h>
18 #include <linux/slab.h>
19 #include <linux/scmi_protocol.h>
20 #include <linux/types.h>
24 struct device *cpu_dev;
27 static const struct scmi_handle *handle;
29 static unsigned int scmi_cpufreq_get_rate(unsigned int cpu)
31 struct cpufreq_policy *policy = cpufreq_cpu_get_raw(cpu);
32 struct scmi_perf_ops *perf_ops = handle->perf_ops;
33 struct scmi_data *priv = policy->driver_data;
37 ret = perf_ops->freq_get(handle, priv->domain_id, &rate, false);
44 * perf_ops->freq_set is not a synchronous, the actual OPP change will
45 * happen asynchronously and can get notified if the events are
46 * subscribed for by the SCMI firmware
49 scmi_cpufreq_set_target(struct cpufreq_policy *policy, unsigned int index)
52 struct scmi_data *priv = policy->driver_data;
53 struct scmi_perf_ops *perf_ops = handle->perf_ops;
54 u64 freq = policy->freq_table[index].frequency;
56 ret = perf_ops->freq_set(handle, priv->domain_id, freq * 1000, false);
58 arch_set_freq_scale(policy->related_cpus, freq,
59 policy->cpuinfo.max_freq);
63 static unsigned int scmi_cpufreq_fast_switch(struct cpufreq_policy *policy,
64 unsigned int target_freq)
66 struct scmi_data *priv = policy->driver_data;
67 struct scmi_perf_ops *perf_ops = handle->perf_ops;
69 if (!perf_ops->freq_set(handle, priv->domain_id,
70 target_freq * 1000, true)) {
71 arch_set_freq_scale(policy->related_cpus, target_freq,
72 policy->cpuinfo.max_freq);
80 scmi_get_sharing_cpus(struct device *cpu_dev, struct cpumask *cpumask)
82 int cpu, domain, tdomain;
83 struct device *tcpu_dev;
85 domain = handle->perf_ops->device_domain_id(cpu_dev);
89 for_each_possible_cpu(cpu) {
90 if (cpu == cpu_dev->id)
93 tcpu_dev = get_cpu_device(cpu);
97 tdomain = handle->perf_ops->device_domain_id(tcpu_dev);
98 if (tdomain == domain)
99 cpumask_set_cpu(cpu, cpumask);
105 static int __maybe_unused
106 scmi_get_cpu_power(unsigned long *power, unsigned long *KHz,
107 struct device *cpu_dev)
112 domain = handle->perf_ops->device_domain_id(cpu_dev);
116 /* Get the power cost of the performance domain. */
118 ret = handle->perf_ops->est_power_get(handle, domain, &Hz, power);
122 /* The EM framework specifies the frequency in KHz. */
128 static int scmi_cpufreq_init(struct cpufreq_policy *policy)
131 unsigned int latency;
132 struct device *cpu_dev;
133 struct scmi_data *priv;
134 struct cpufreq_frequency_table *freq_table;
135 struct em_data_callback em_cb = EM_DATA_CB(scmi_get_cpu_power);
137 cpu_dev = get_cpu_device(policy->cpu);
139 pr_err("failed to get cpu%d device\n", policy->cpu);
143 ret = handle->perf_ops->device_opps_add(handle, cpu_dev);
145 dev_warn(cpu_dev, "failed to add opps to the device\n");
149 ret = scmi_get_sharing_cpus(cpu_dev, policy->cpus);
151 dev_warn(cpu_dev, "failed to get sharing cpumask\n");
155 ret = dev_pm_opp_set_sharing_cpus(cpu_dev, policy->cpus);
157 dev_err(cpu_dev, "%s: failed to mark OPPs as shared: %d\n",
162 nr_opp = dev_pm_opp_get_opp_count(cpu_dev);
164 dev_dbg(cpu_dev, "OPP table is not ready, deferring probe\n");
169 priv = kzalloc(sizeof(*priv), GFP_KERNEL);
175 ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table);
177 dev_err(cpu_dev, "failed to init cpufreq table: %d\n", ret);
181 priv->cpu_dev = cpu_dev;
182 priv->domain_id = handle->perf_ops->device_domain_id(cpu_dev);
184 policy->driver_data = priv;
185 policy->freq_table = freq_table;
187 /* SCMI allows DVFS request for any domain from any CPU */
188 policy->dvfs_possible_from_any_cpu = true;
190 latency = handle->perf_ops->transition_latency_get(handle, cpu_dev);
192 latency = CPUFREQ_ETERNAL;
194 policy->cpuinfo.transition_latency = latency;
196 policy->fast_switch_possible =
197 handle->perf_ops->fast_switch_possible(handle, cpu_dev);
199 em_dev_register_perf_domain(cpu_dev, nr_opp, &em_cb, policy->cpus);
206 dev_pm_opp_remove_all_dynamic(cpu_dev);
211 static int scmi_cpufreq_exit(struct cpufreq_policy *policy)
213 struct scmi_data *priv = policy->driver_data;
215 dev_pm_opp_free_cpufreq_table(priv->cpu_dev, &policy->freq_table);
216 dev_pm_opp_remove_all_dynamic(priv->cpu_dev);
222 static struct cpufreq_driver scmi_cpufreq_driver = {
224 .flags = CPUFREQ_STICKY | CPUFREQ_HAVE_GOVERNOR_PER_POLICY |
225 CPUFREQ_NEED_INITIAL_FREQ_CHECK |
226 CPUFREQ_IS_COOLING_DEV,
227 .verify = cpufreq_generic_frequency_table_verify,
228 .attr = cpufreq_generic_attr,
229 .target_index = scmi_cpufreq_set_target,
230 .fast_switch = scmi_cpufreq_fast_switch,
231 .get = scmi_cpufreq_get_rate,
232 .init = scmi_cpufreq_init,
233 .exit = scmi_cpufreq_exit,
236 static int scmi_cpufreq_probe(struct scmi_device *sdev)
240 handle = sdev->handle;
242 if (!handle || !handle->perf_ops)
245 ret = cpufreq_register_driver(&scmi_cpufreq_driver);
247 dev_err(&sdev->dev, "%s: registering cpufreq failed, err: %d\n",
254 static void scmi_cpufreq_remove(struct scmi_device *sdev)
256 cpufreq_unregister_driver(&scmi_cpufreq_driver);
259 static const struct scmi_device_id scmi_id_table[] = {
260 { SCMI_PROTOCOL_PERF, "cpufreq" },
263 MODULE_DEVICE_TABLE(scmi, scmi_id_table);
265 static struct scmi_driver scmi_cpufreq_drv = {
266 .name = "scmi-cpufreq",
267 .probe = scmi_cpufreq_probe,
268 .remove = scmi_cpufreq_remove,
269 .id_table = scmi_id_table,
271 module_scmi_driver(scmi_cpufreq_drv);
273 MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>");
274 MODULE_DESCRIPTION("ARM SCMI CPUFreq interface driver");
275 MODULE_LICENSE("GPL v2");