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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,
107 struct device *cpu_dev)
108{
109 unsigned long Hz;
110 int ret, domain;
111
112 domain = handle->perf_ops->device_domain_id(cpu_dev);
113 if (domain < 0)
114 return domain;
115
116
117 Hz = *KHz * 1000;
118 ret = handle->perf_ops->est_power_get(handle, domain, &Hz, power);
119 if (ret)
120 return ret;
121
122
123 *KHz = Hz / 1000;
124
125 return 0;
126}
127
128static int scmi_cpufreq_init(struct cpufreq_policy *policy)
129{
130 int ret, nr_opp;
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);
136
137 cpu_dev = get_cpu_device(policy->cpu);
138 if (!cpu_dev) {
139 pr_err("failed to get cpu%d device\n", policy->cpu);
140 return -ENODEV;
141 }
142
143 ret = handle->perf_ops->device_opps_add(handle, cpu_dev);
144 if (ret) {
145 dev_warn(cpu_dev, "failed to add opps to the device\n");
146 return ret;
147 }
148
149 ret = scmi_get_sharing_cpus(cpu_dev, policy->cpus);
150 if (ret) {
151 dev_warn(cpu_dev, "failed to get sharing cpumask\n");
152 return ret;
153 }
154
155 ret = dev_pm_opp_set_sharing_cpus(cpu_dev, policy->cpus);
156 if (ret) {
157 dev_err(cpu_dev, "%s: failed to mark OPPs as shared: %d\n",
158 __func__, ret);
159 return ret;
160 }
161
162 nr_opp = dev_pm_opp_get_opp_count(cpu_dev);
163 if (nr_opp <= 0) {
164 dev_dbg(cpu_dev, "OPP table is not ready, deferring probe\n");
165 ret = -EPROBE_DEFER;
166 goto out_free_opp;
167 }
168
169 priv = kzalloc(sizeof(*priv), GFP_KERNEL);
170 if (!priv) {
171 ret = -ENOMEM;
172 goto out_free_opp;
173 }
174
175 ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table);
176 if (ret) {
177 dev_err(cpu_dev, "failed to init cpufreq table: %d\n", ret);
178 goto out_free_priv;
179 }
180
181 priv->cpu_dev = cpu_dev;
182 priv->domain_id = handle->perf_ops->device_domain_id(cpu_dev);
183
184 policy->driver_data = priv;
185 policy->freq_table = freq_table;
186
187
188 policy->dvfs_possible_from_any_cpu = true;
189
190 latency = handle->perf_ops->transition_latency_get(handle, cpu_dev);
191 if (!latency)
192 latency = CPUFREQ_ETERNAL;
193
194 policy->cpuinfo.transition_latency = latency;
195
196 policy->fast_switch_possible =
197 handle->perf_ops->fast_switch_possible(handle, cpu_dev);
198
199 em_dev_register_perf_domain(cpu_dev, nr_opp, &em_cb, policy->cpus);
200
201 return 0;
202
203out_free_priv:
204 kfree(priv);
205out_free_opp:
206 dev_pm_opp_remove_all_dynamic(cpu_dev);
207
208 return ret;
209}
210
211static int scmi_cpufreq_exit(struct cpufreq_policy *policy)
212{
213 struct scmi_data *priv = policy->driver_data;
214
215 dev_pm_opp_free_cpufreq_table(priv->cpu_dev, &policy->freq_table);
216 dev_pm_opp_remove_all_dynamic(priv->cpu_dev);
217 kfree(priv);
218
219 return 0;
220}
221
222static struct cpufreq_driver scmi_cpufreq_driver = {
223 .name = "scmi",
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,
234};
235
236static int scmi_cpufreq_probe(struct scmi_device *sdev)
237{
238 int ret;
239
240 handle = sdev->handle;
241
242 if (!handle || !handle->perf_ops)
243 return -ENODEV;
244
245 ret = cpufreq_register_driver(&scmi_cpufreq_driver);
246 if (ret) {
247 dev_err(&sdev->dev, "%s: registering cpufreq failed, err: %d\n",
248 __func__, ret);
249 }
250
251 return ret;
252}
253
254static void scmi_cpufreq_remove(struct scmi_device *sdev)
255{
256 cpufreq_unregister_driver(&scmi_cpufreq_driver);
257}
258
259static const struct scmi_device_id scmi_id_table[] = {
260 { SCMI_PROTOCOL_PERF, "cpufreq" },
261 { },
262};
263MODULE_DEVICE_TABLE(scmi, scmi_id_table);
264
265static 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,
270};
271module_scmi_driver(scmi_cpufreq_drv);
272
273MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>");
274MODULE_DESCRIPTION("ARM SCMI CPUFreq interface driver");
275MODULE_LICENSE("GPL v2");
276
