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9#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
10
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>
21
22struct scmi_data {
23 int domain_id;
24 struct device *cpu_dev;
25};
26
27static const struct scmi_handle *handle;
28
29static unsigned int scmi_cpufreq_get_rate(unsigned int cpu)
30{
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;
34 unsigned long rate;
35 int ret;
36
37 ret = perf_ops->freq_get(handle, priv->domain_id, &rate, false);
38 if (ret)
39 return 0;
40 return rate / 1000;
41}
42
43
44
45
46
47
48static int
49scmi_cpufreq_set_target(struct cpufreq_policy *policy, unsigned int index)
50{
51 int ret;
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;
55
56 ret = perf_ops->freq_set(handle, priv->domain_id, freq * 1000, false);
57 if (!ret)
58 arch_set_freq_scale(policy->related_cpus, freq,
59 policy->cpuinfo.max_freq);
60 return ret;
61}
62
63static unsigned int scmi_cpufreq_fast_switch(struct cpufreq_policy *policy,
64 unsigned int target_freq)
65{
66 struct scmi_data *priv = policy->driver_data;
67 struct scmi_perf_ops *perf_ops = handle->perf_ops;
68
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);
73 return target_freq;
74 }
75
76 return 0;
77}
78
79static int
80scmi_get_sharing_cpus(struct device *cpu_dev, struct cpumask *cpumask)
81{
82 int cpu, domain, tdomain;
83 struct device *tcpu_dev;
84
85 domain = handle->perf_ops->device_domain_id(cpu_dev);
86 if (domain < 0)
87 return domain;
88
89 for_each_possible_cpu(cpu) {
90 if (cpu == cpu_dev->id)
91 continue;
92
93 tcpu_dev = get_cpu_device(cpu);
94 if (!tcpu_dev)
95 continue;
96
97 tdomain = handle->perf_ops->device_domain_id(tcpu_dev);
98 if (tdomain == domain)
99 cpumask_set_cpu(cpu, cpumask);
100 }
101
102 return 0;
103}
104
105static int __maybe_unused
106scmi_get_cpu_power(unsigned long *power, unsigned long *KHz, int cpu)
107{
108 struct device *cpu_dev = get_cpu_device(cpu);
109 unsigned long Hz;
110 int ret, domain;
111
112 if (!cpu_dev) {
113 pr_err("failed to get cpu%d device\n", cpu);
114 return -ENODEV;
115 }
116
117 domain = handle->perf_ops->device_domain_id(cpu_dev);
118 if (domain < 0)
119 return domain;
120
121
122 Hz = *KHz * 1000;
123 ret = handle->perf_ops->est_power_get(handle, domain, &Hz, power);
124 if (ret)
125 return ret;
126
127
128 *KHz = Hz / 1000;
129
130 return 0;
131}
132
133static int scmi_cpufreq_init(struct cpufreq_policy *policy)
134{
135 int ret, nr_opp;
136 unsigned int latency;
137 struct device *cpu_dev;
138 struct scmi_data *priv;
139 struct cpufreq_frequency_table *freq_table;
140 struct em_data_callback em_cb = EM_DATA_CB(scmi_get_cpu_power);
141
142 cpu_dev = get_cpu_device(policy->cpu);
143 if (!cpu_dev) {
144 pr_err("failed to get cpu%d device\n", policy->cpu);
145 return -ENODEV;
146 }
147
148 ret = handle->perf_ops->device_opps_add(handle, cpu_dev);
149 if (ret) {
150 dev_warn(cpu_dev, "failed to add opps to the device\n");
151 return ret;
152 }
153
154 ret = scmi_get_sharing_cpus(cpu_dev, policy->cpus);
155 if (ret) {
156 dev_warn(cpu_dev, "failed to get sharing cpumask\n");
157 return ret;
158 }
159
160 ret = dev_pm_opp_set_sharing_cpus(cpu_dev, policy->cpus);
161 if (ret) {
162 dev_err(cpu_dev, "%s: failed to mark OPPs as shared: %d\n",
163 __func__, ret);
164 return ret;
165 }
166
167 nr_opp = dev_pm_opp_get_opp_count(cpu_dev);
168 if (nr_opp <= 0) {
169 dev_dbg(cpu_dev, "OPP table is not ready, deferring probe\n");
170 ret = -EPROBE_DEFER;
171 goto out_free_opp;
172 }
173
174 priv = kzalloc(sizeof(*priv), GFP_KERNEL);
175 if (!priv) {
176 ret = -ENOMEM;
177 goto out_free_opp;
178 }
179
180 ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table);
181 if (ret) {
182 dev_err(cpu_dev, "failed to init cpufreq table: %d\n", ret);
183 goto out_free_priv;
184 }
185
186 priv->cpu_dev = cpu_dev;
187 priv->domain_id = handle->perf_ops->device_domain_id(cpu_dev);
188
189 policy->driver_data = priv;
190 policy->freq_table = freq_table;
191
192
193 policy->dvfs_possible_from_any_cpu = true;
194
195 latency = handle->perf_ops->transition_latency_get(handle, cpu_dev);
196 if (!latency)
197 latency = CPUFREQ_ETERNAL;
198
199 policy->cpuinfo.transition_latency = latency;
200
201 policy->fast_switch_possible = true;
202
203 em_register_perf_domain(policy->cpus, nr_opp, &em_cb);
204
205 return 0;
206
207out_free_priv:
208 kfree(priv);
209out_free_opp:
210 dev_pm_opp_remove_all_dynamic(cpu_dev);
211
212 return ret;
213}
214
215static int scmi_cpufreq_exit(struct cpufreq_policy *policy)
216{
217 struct scmi_data *priv = policy->driver_data;
218
219 dev_pm_opp_free_cpufreq_table(priv->cpu_dev, &policy->freq_table);
220 dev_pm_opp_remove_all_dynamic(priv->cpu_dev);
221 kfree(priv);
222
223 return 0;
224}
225
226static struct cpufreq_driver scmi_cpufreq_driver = {
227 .name = "scmi",
228 .flags = CPUFREQ_STICKY | CPUFREQ_HAVE_GOVERNOR_PER_POLICY |
229 CPUFREQ_NEED_INITIAL_FREQ_CHECK |
230 CPUFREQ_IS_COOLING_DEV,
231 .verify = cpufreq_generic_frequency_table_verify,
232 .attr = cpufreq_generic_attr,
233 .target_index = scmi_cpufreq_set_target,
234 .fast_switch = scmi_cpufreq_fast_switch,
235 .get = scmi_cpufreq_get_rate,
236 .init = scmi_cpufreq_init,
237 .exit = scmi_cpufreq_exit,
238};
239
240static int scmi_cpufreq_probe(struct scmi_device *sdev)
241{
242 int ret;
243
244 handle = sdev->handle;
245
246 if (!handle || !handle->perf_ops)
247 return -ENODEV;
248
249 ret = cpufreq_register_driver(&scmi_cpufreq_driver);
250 if (ret) {
251 dev_err(&sdev->dev, "%s: registering cpufreq failed, err: %d\n",
252 __func__, ret);
253 }
254
255 return ret;
256}
257
258static void scmi_cpufreq_remove(struct scmi_device *sdev)
259{
260 cpufreq_unregister_driver(&scmi_cpufreq_driver);
261}
262
263static const struct scmi_device_id scmi_id_table[] = {
264 { SCMI_PROTOCOL_PERF },
265 { },
266};
267MODULE_DEVICE_TABLE(scmi, scmi_id_table);
268
269static struct scmi_driver scmi_cpufreq_drv = {
270 .name = "scmi-cpufreq",
271 .probe = scmi_cpufreq_probe,
272 .remove = scmi_cpufreq_remove,
273 .id_table = scmi_id_table,
274};
275module_scmi_driver(scmi_cpufreq_drv);
276
277MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>");
278MODULE_DESCRIPTION("ARM SCMI CPUFreq interface driver");
279MODULE_LICENSE("GPL v2");
280
