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 const 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)
51 struct scmi_data *priv = policy->driver_data;
52 const struct scmi_perf_ops *perf_ops = handle->perf_ops;
53 u64 freq = policy->freq_table[index].frequency;
55 return perf_ops->freq_set(handle, priv->domain_id, freq * 1000, false);
58 static unsigned int scmi_cpufreq_fast_switch(struct cpufreq_policy *policy,
59 unsigned int target_freq)
61 struct scmi_data *priv = policy->driver_data;
62 const struct scmi_perf_ops *perf_ops = handle->perf_ops;
64 if (!perf_ops->freq_set(handle, priv->domain_id,
65 target_freq * 1000, true))
72 scmi_get_sharing_cpus(struct device *cpu_dev, struct cpumask *cpumask)
74 int cpu, domain, tdomain;
75 struct device *tcpu_dev;
77 domain = handle->perf_ops->device_domain_id(cpu_dev);
81 for_each_possible_cpu(cpu) {
82 if (cpu == cpu_dev->id)
85 tcpu_dev = get_cpu_device(cpu);
89 tdomain = handle->perf_ops->device_domain_id(tcpu_dev);
90 if (tdomain == domain)
91 cpumask_set_cpu(cpu, cpumask);
97 static int __maybe_unused
98 scmi_get_cpu_power(unsigned long *power, unsigned long *KHz,
99 struct device *cpu_dev)
104 domain = handle->perf_ops->device_domain_id(cpu_dev);
108 /* Get the power cost of the performance domain. */
110 ret = handle->perf_ops->est_power_get(handle, domain, &Hz, power);
114 /* The EM framework specifies the frequency in KHz. */
120 static int scmi_cpufreq_init(struct cpufreq_policy *policy)
123 unsigned int latency;
124 struct device *cpu_dev;
125 struct scmi_data *priv;
126 struct cpufreq_frequency_table *freq_table;
127 struct em_data_callback em_cb = EM_DATA_CB(scmi_get_cpu_power);
129 cpu_dev = get_cpu_device(policy->cpu);
131 pr_err("failed to get cpu%d device\n", policy->cpu);
135 ret = handle->perf_ops->device_opps_add(handle, cpu_dev);
137 dev_warn(cpu_dev, "failed to add opps to the device\n");
141 ret = scmi_get_sharing_cpus(cpu_dev, policy->cpus);
143 dev_warn(cpu_dev, "failed to get sharing cpumask\n");
147 ret = dev_pm_opp_set_sharing_cpus(cpu_dev, policy->cpus);
149 dev_err(cpu_dev, "%s: failed to mark OPPs as shared: %d\n",
154 nr_opp = dev_pm_opp_get_opp_count(cpu_dev);
156 dev_dbg(cpu_dev, "OPP table is not ready, deferring probe\n");
161 priv = kzalloc(sizeof(*priv), GFP_KERNEL);
167 ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table);
169 dev_err(cpu_dev, "failed to init cpufreq table: %d\n", ret);
173 priv->cpu_dev = cpu_dev;
174 priv->domain_id = handle->perf_ops->device_domain_id(cpu_dev);
176 policy->driver_data = priv;
177 policy->freq_table = freq_table;
179 /* SCMI allows DVFS request for any domain from any CPU */
180 policy->dvfs_possible_from_any_cpu = true;
182 latency = handle->perf_ops->transition_latency_get(handle, cpu_dev);
184 latency = CPUFREQ_ETERNAL;
186 policy->cpuinfo.transition_latency = latency;
188 policy->fast_switch_possible =
189 handle->perf_ops->fast_switch_possible(handle, cpu_dev);
191 em_dev_register_perf_domain(cpu_dev, nr_opp, &em_cb, policy->cpus);
198 dev_pm_opp_remove_all_dynamic(cpu_dev);
203 static int scmi_cpufreq_exit(struct cpufreq_policy *policy)
205 struct scmi_data *priv = policy->driver_data;
207 dev_pm_opp_free_cpufreq_table(priv->cpu_dev, &policy->freq_table);
208 dev_pm_opp_remove_all_dynamic(priv->cpu_dev);
214 static struct cpufreq_driver scmi_cpufreq_driver = {
216 .flags = CPUFREQ_STICKY | CPUFREQ_HAVE_GOVERNOR_PER_POLICY |
217 CPUFREQ_NEED_INITIAL_FREQ_CHECK |
218 CPUFREQ_IS_COOLING_DEV,
219 .verify = cpufreq_generic_frequency_table_verify,
220 .attr = cpufreq_generic_attr,
221 .target_index = scmi_cpufreq_set_target,
222 .fast_switch = scmi_cpufreq_fast_switch,
223 .get = scmi_cpufreq_get_rate,
224 .init = scmi_cpufreq_init,
225 .exit = scmi_cpufreq_exit,
228 static int scmi_cpufreq_probe(struct scmi_device *sdev)
232 handle = sdev->handle;
234 if (!handle || !handle->perf_ops)
237 ret = cpufreq_register_driver(&scmi_cpufreq_driver);
239 dev_err(&sdev->dev, "%s: registering cpufreq failed, err: %d\n",
246 static void scmi_cpufreq_remove(struct scmi_device *sdev)
248 cpufreq_unregister_driver(&scmi_cpufreq_driver);
251 static const struct scmi_device_id scmi_id_table[] = {
252 { SCMI_PROTOCOL_PERF, "cpufreq" },
255 MODULE_DEVICE_TABLE(scmi, scmi_id_table);
257 static struct scmi_driver scmi_cpufreq_drv = {
258 .name = "scmi-cpufreq",
259 .probe = scmi_cpufreq_probe,
260 .remove = scmi_cpufreq_remove,
261 .id_table = scmi_id_table,
263 module_scmi_driver(scmi_cpufreq_drv);
265 MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>");
266 MODULE_DESCRIPTION("ARM SCMI CPUFreq interface driver");
267 MODULE_LICENSE("GPL v2");