Merge tag 'regulator-fix-v5.15-rc2' of git://git.kernel.org/pub/scm/linux/kernel...
[linux-2.6-microblaze.git] / drivers / cpufreq / scmi-cpufreq.c
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * System Control and Power Interface (SCMI) based CPUFreq Interface driver
4  *
5  * Copyright (C) 2018-2021 ARM Ltd.
6  * Sudeep Holla <sudeep.holla@arm.com>
7  */
8
9 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
10
11 #include <linux/clk-provider.h>
12 #include <linux/cpu.h>
13 #include <linux/cpufreq.h>
14 #include <linux/cpumask.h>
15 #include <linux/energy_model.h>
16 #include <linux/export.h>
17 #include <linux/module.h>
18 #include <linux/pm_opp.h>
19 #include <linux/slab.h>
20 #include <linux/scmi_protocol.h>
21 #include <linux/types.h>
22
23 struct scmi_data {
24         int domain_id;
25         int nr_opp;
26         struct device *cpu_dev;
27         cpumask_var_t opp_shared_cpus;
28 };
29
30 static struct scmi_protocol_handle *ph;
31 static const struct scmi_perf_proto_ops *perf_ops;
32
33 static unsigned int scmi_cpufreq_get_rate(unsigned int cpu)
34 {
35         struct cpufreq_policy *policy = cpufreq_cpu_get_raw(cpu);
36         struct scmi_data *priv = policy->driver_data;
37         unsigned long rate;
38         int ret;
39
40         ret = perf_ops->freq_get(ph, priv->domain_id, &rate, false);
41         if (ret)
42                 return 0;
43         return rate / 1000;
44 }
45
46 /*
47  * perf_ops->freq_set is not a synchronous, the actual OPP change will
48  * happen asynchronously and can get notified if the events are
49  * subscribed for by the SCMI firmware
50  */
51 static int
52 scmi_cpufreq_set_target(struct cpufreq_policy *policy, unsigned int index)
53 {
54         struct scmi_data *priv = policy->driver_data;
55         u64 freq = policy->freq_table[index].frequency;
56
57         return perf_ops->freq_set(ph, priv->domain_id, freq * 1000, false);
58 }
59
60 static unsigned int scmi_cpufreq_fast_switch(struct cpufreq_policy *policy,
61                                              unsigned int target_freq)
62 {
63         struct scmi_data *priv = policy->driver_data;
64
65         if (!perf_ops->freq_set(ph, priv->domain_id,
66                                 target_freq * 1000, true))
67                 return target_freq;
68
69         return 0;
70 }
71
72 static int
73 scmi_get_sharing_cpus(struct device *cpu_dev, struct cpumask *cpumask)
74 {
75         int cpu, domain, tdomain;
76         struct device *tcpu_dev;
77
78         domain = perf_ops->device_domain_id(cpu_dev);
79         if (domain < 0)
80                 return domain;
81
82         for_each_possible_cpu(cpu) {
83                 if (cpu == cpu_dev->id)
84                         continue;
85
86                 tcpu_dev = get_cpu_device(cpu);
87                 if (!tcpu_dev)
88                         continue;
89
90                 tdomain = perf_ops->device_domain_id(tcpu_dev);
91                 if (tdomain == domain)
92                         cpumask_set_cpu(cpu, cpumask);
93         }
94
95         return 0;
96 }
97
98 static int __maybe_unused
99 scmi_get_cpu_power(unsigned long *power, unsigned long *KHz,
100                    struct device *cpu_dev)
101 {
102         unsigned long Hz;
103         int ret, domain;
104
105         domain = perf_ops->device_domain_id(cpu_dev);
106         if (domain < 0)
107                 return domain;
108
109         /* Get the power cost of the performance domain. */
110         Hz = *KHz * 1000;
111         ret = perf_ops->est_power_get(ph, domain, &Hz, power);
112         if (ret)
113                 return ret;
114
115         /* The EM framework specifies the frequency in KHz. */
116         *KHz = Hz / 1000;
117
118         return 0;
119 }
120
121 static int scmi_cpufreq_init(struct cpufreq_policy *policy)
122 {
123         int ret, nr_opp;
124         unsigned int latency;
125         struct device *cpu_dev;
126         struct scmi_data *priv;
127         struct cpufreq_frequency_table *freq_table;
128
129         cpu_dev = get_cpu_device(policy->cpu);
130         if (!cpu_dev) {
131                 pr_err("failed to get cpu%d device\n", policy->cpu);
132                 return -ENODEV;
133         }
134
135         priv = kzalloc(sizeof(*priv), GFP_KERNEL);
136         if (!priv)
137                 return -ENOMEM;
138
139         if (!zalloc_cpumask_var(&priv->opp_shared_cpus, GFP_KERNEL)) {
140                 ret = -ENOMEM;
141                 goto out_free_priv;
142         }
143
144         /* Obtain CPUs that share SCMI performance controls */
145         ret = scmi_get_sharing_cpus(cpu_dev, policy->cpus);
146         if (ret) {
147                 dev_warn(cpu_dev, "failed to get sharing cpumask\n");
148                 goto out_free_cpumask;
149         }
150
151         /*
152          * Obtain CPUs that share performance levels.
153          * The OPP 'sharing cpus' info may come from DT through an empty opp
154          * table and opp-shared.
155          */
156         ret = dev_pm_opp_of_get_sharing_cpus(cpu_dev, priv->opp_shared_cpus);
157         if (ret || !cpumask_weight(priv->opp_shared_cpus)) {
158                 /*
159                  * Either opp-table is not set or no opp-shared was found.
160                  * Use the CPU mask from SCMI to designate CPUs sharing an OPP
161                  * table.
162                  */
163                 cpumask_copy(priv->opp_shared_cpus, policy->cpus);
164         }
165
166          /*
167           * A previous CPU may have marked OPPs as shared for a few CPUs, based on
168           * what OPP core provided. If the current CPU is part of those few, then
169           * there is no need to add OPPs again.
170           */
171         nr_opp = dev_pm_opp_get_opp_count(cpu_dev);
172         if (nr_opp <= 0) {
173                 ret = perf_ops->device_opps_add(ph, cpu_dev);
174                 if (ret) {
175                         dev_warn(cpu_dev, "failed to add opps to the device\n");
176                         goto out_free_cpumask;
177                 }
178
179                 nr_opp = dev_pm_opp_get_opp_count(cpu_dev);
180                 if (nr_opp <= 0) {
181                         dev_err(cpu_dev, "%s: No OPPs for this device: %d\n",
182                                 __func__, nr_opp);
183
184                         ret = -ENODEV;
185                         goto out_free_opp;
186                 }
187
188                 ret = dev_pm_opp_set_sharing_cpus(cpu_dev, priv->opp_shared_cpus);
189                 if (ret) {
190                         dev_err(cpu_dev, "%s: failed to mark OPPs as shared: %d\n",
191                                 __func__, ret);
192
193                         goto out_free_opp;
194                 }
195
196                 priv->nr_opp = nr_opp;
197         }
198
199         ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table);
200         if (ret) {
201                 dev_err(cpu_dev, "failed to init cpufreq table: %d\n", ret);
202                 goto out_free_opp;
203         }
204
205         priv->cpu_dev = cpu_dev;
206         priv->domain_id = perf_ops->device_domain_id(cpu_dev);
207
208         policy->driver_data = priv;
209         policy->freq_table = freq_table;
210
211         /* SCMI allows DVFS request for any domain from any CPU */
212         policy->dvfs_possible_from_any_cpu = true;
213
214         latency = perf_ops->transition_latency_get(ph, cpu_dev);
215         if (!latency)
216                 latency = CPUFREQ_ETERNAL;
217
218         policy->cpuinfo.transition_latency = latency;
219
220         policy->fast_switch_possible =
221                 perf_ops->fast_switch_possible(ph, cpu_dev);
222
223         return 0;
224
225 out_free_opp:
226         dev_pm_opp_remove_all_dynamic(cpu_dev);
227
228 out_free_cpumask:
229         free_cpumask_var(priv->opp_shared_cpus);
230
231 out_free_priv:
232         kfree(priv);
233
234         return ret;
235 }
236
237 static int scmi_cpufreq_exit(struct cpufreq_policy *policy)
238 {
239         struct scmi_data *priv = policy->driver_data;
240
241         dev_pm_opp_free_cpufreq_table(priv->cpu_dev, &policy->freq_table);
242         dev_pm_opp_remove_all_dynamic(priv->cpu_dev);
243         free_cpumask_var(priv->opp_shared_cpus);
244         kfree(priv);
245
246         return 0;
247 }
248
249 static void scmi_cpufreq_register_em(struct cpufreq_policy *policy)
250 {
251         struct em_data_callback em_cb = EM_DATA_CB(scmi_get_cpu_power);
252         bool power_scale_mw = perf_ops->power_scale_mw_get(ph);
253         struct scmi_data *priv = policy->driver_data;
254
255         /*
256          * This callback will be called for each policy, but we don't need to
257          * register with EM every time. Despite not being part of the same
258          * policy, some CPUs may still share their perf-domains, and a CPU from
259          * another policy may already have registered with EM on behalf of CPUs
260          * of this policy.
261          */
262         if (!priv->nr_opp)
263                 return;
264
265         em_dev_register_perf_domain(get_cpu_device(policy->cpu), priv->nr_opp,
266                                     &em_cb, priv->opp_shared_cpus,
267                                     power_scale_mw);
268 }
269
270 static struct cpufreq_driver scmi_cpufreq_driver = {
271         .name   = "scmi",
272         .flags  = CPUFREQ_HAVE_GOVERNOR_PER_POLICY |
273                   CPUFREQ_NEED_INITIAL_FREQ_CHECK |
274                   CPUFREQ_IS_COOLING_DEV,
275         .verify = cpufreq_generic_frequency_table_verify,
276         .attr   = cpufreq_generic_attr,
277         .target_index   = scmi_cpufreq_set_target,
278         .fast_switch    = scmi_cpufreq_fast_switch,
279         .get    = scmi_cpufreq_get_rate,
280         .init   = scmi_cpufreq_init,
281         .exit   = scmi_cpufreq_exit,
282         .register_em    = scmi_cpufreq_register_em,
283 };
284
285 static int scmi_cpufreq_probe(struct scmi_device *sdev)
286 {
287         int ret;
288         struct device *dev = &sdev->dev;
289         const struct scmi_handle *handle;
290
291         handle = sdev->handle;
292
293         if (!handle)
294                 return -ENODEV;
295
296         perf_ops = handle->devm_protocol_get(sdev, SCMI_PROTOCOL_PERF, &ph);
297         if (IS_ERR(perf_ops))
298                 return PTR_ERR(perf_ops);
299
300 #ifdef CONFIG_COMMON_CLK
301         /* dummy clock provider as needed by OPP if clocks property is used */
302         if (of_find_property(dev->of_node, "#clock-cells", NULL))
303                 devm_of_clk_add_hw_provider(dev, of_clk_hw_simple_get, NULL);
304 #endif
305
306         ret = cpufreq_register_driver(&scmi_cpufreq_driver);
307         if (ret) {
308                 dev_err(dev, "%s: registering cpufreq failed, err: %d\n",
309                         __func__, ret);
310         }
311
312         return ret;
313 }
314
315 static void scmi_cpufreq_remove(struct scmi_device *sdev)
316 {
317         cpufreq_unregister_driver(&scmi_cpufreq_driver);
318 }
319
320 static const struct scmi_device_id scmi_id_table[] = {
321         { SCMI_PROTOCOL_PERF, "cpufreq" },
322         { },
323 };
324 MODULE_DEVICE_TABLE(scmi, scmi_id_table);
325
326 static struct scmi_driver scmi_cpufreq_drv = {
327         .name           = "scmi-cpufreq",
328         .probe          = scmi_cpufreq_probe,
329         .remove         = scmi_cpufreq_remove,
330         .id_table       = scmi_id_table,
331 };
332 module_scmi_driver(scmi_cpufreq_drv);
333
334 MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>");
335 MODULE_DESCRIPTION("ARM SCMI CPUFreq interface driver");
336 MODULE_LICENSE("GPL v2");