Merge tag 'icc-6.7-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/djakov/icc...
[linux-2.6-microblaze.git] / drivers / powercap / dtpm_cpu.c
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright 2020 Linaro Limited
4  *
5  * Author: Daniel Lezcano <daniel.lezcano@linaro.org>
6  *
7  * The DTPM CPU is based on the energy model. It hooks the CPU in the
8  * DTPM tree which in turns update the power number by propagating the
9  * power number from the CPU energy model information to the parents.
10  *
11  * The association between the power and the performance state, allows
12  * to set the power of the CPU at the OPP granularity.
13  *
14  * The CPU hotplug is supported and the power numbers will be updated
15  * if a CPU is hot plugged / unplugged.
16  */
17 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
18
19 #include <linux/cpumask.h>
20 #include <linux/cpufreq.h>
21 #include <linux/cpuhotplug.h>
22 #include <linux/dtpm.h>
23 #include <linux/energy_model.h>
24 #include <linux/of.h>
25 #include <linux/pm_qos.h>
26 #include <linux/slab.h>
27
28 struct dtpm_cpu {
29         struct dtpm dtpm;
30         struct freq_qos_request qos_req;
31         int cpu;
32 };
33
34 static DEFINE_PER_CPU(struct dtpm_cpu *, dtpm_per_cpu);
35
36 static struct dtpm_cpu *to_dtpm_cpu(struct dtpm *dtpm)
37 {
38         return container_of(dtpm, struct dtpm_cpu, dtpm);
39 }
40
41 static u64 set_pd_power_limit(struct dtpm *dtpm, u64 power_limit)
42 {
43         struct dtpm_cpu *dtpm_cpu = to_dtpm_cpu(dtpm);
44         struct em_perf_domain *pd = em_cpu_get(dtpm_cpu->cpu);
45         struct cpumask cpus;
46         unsigned long freq;
47         u64 power;
48         int i, nr_cpus;
49
50         cpumask_and(&cpus, cpu_online_mask, to_cpumask(pd->cpus));
51         nr_cpus = cpumask_weight(&cpus);
52
53         for (i = 0; i < pd->nr_perf_states; i++) {
54
55                 power = pd->table[i].power * nr_cpus;
56
57                 if (power > power_limit)
58                         break;
59         }
60
61         freq = pd->table[i - 1].frequency;
62
63         freq_qos_update_request(&dtpm_cpu->qos_req, freq);
64
65         power_limit = pd->table[i - 1].power * nr_cpus;
66
67         return power_limit;
68 }
69
70 static u64 scale_pd_power_uw(struct cpumask *pd_mask, u64 power)
71 {
72         unsigned long max, sum_util = 0;
73         int cpu;
74
75         /*
76          * The capacity is the same for all CPUs belonging to
77          * the same perf domain.
78          */
79         max = arch_scale_cpu_capacity(cpumask_first(pd_mask));
80
81         for_each_cpu_and(cpu, pd_mask, cpu_online_mask)
82                 sum_util += sched_cpu_util(cpu);
83
84         return (power * ((sum_util << 10) / max)) >> 10;
85 }
86
87 static u64 get_pd_power_uw(struct dtpm *dtpm)
88 {
89         struct dtpm_cpu *dtpm_cpu = to_dtpm_cpu(dtpm);
90         struct em_perf_domain *pd;
91         struct cpumask *pd_mask;
92         unsigned long freq;
93         int i;
94
95         pd = em_cpu_get(dtpm_cpu->cpu);
96
97         pd_mask = em_span_cpus(pd);
98
99         freq = cpufreq_quick_get(dtpm_cpu->cpu);
100
101         for (i = 0; i < pd->nr_perf_states; i++) {
102
103                 if (pd->table[i].frequency < freq)
104                         continue;
105
106                 return scale_pd_power_uw(pd_mask, pd->table[i].power);
107         }
108
109         return 0;
110 }
111
112 static int update_pd_power_uw(struct dtpm *dtpm)
113 {
114         struct dtpm_cpu *dtpm_cpu = to_dtpm_cpu(dtpm);
115         struct em_perf_domain *em = em_cpu_get(dtpm_cpu->cpu);
116         struct cpumask cpus;
117         int nr_cpus;
118
119         cpumask_and(&cpus, cpu_online_mask, to_cpumask(em->cpus));
120         nr_cpus = cpumask_weight(&cpus);
121
122         dtpm->power_min = em->table[0].power;
123         dtpm->power_min *= nr_cpus;
124
125         dtpm->power_max = em->table[em->nr_perf_states - 1].power;
126         dtpm->power_max *= nr_cpus;
127
128         return 0;
129 }
130
131 static void pd_release(struct dtpm *dtpm)
132 {
133         struct dtpm_cpu *dtpm_cpu = to_dtpm_cpu(dtpm);
134         struct cpufreq_policy *policy;
135
136         if (freq_qos_request_active(&dtpm_cpu->qos_req))
137                 freq_qos_remove_request(&dtpm_cpu->qos_req);
138
139         policy = cpufreq_cpu_get(dtpm_cpu->cpu);
140         if (policy) {
141                 for_each_cpu(dtpm_cpu->cpu, policy->related_cpus)
142                         per_cpu(dtpm_per_cpu, dtpm_cpu->cpu) = NULL;
143
144                 cpufreq_cpu_put(policy);
145         }
146         
147         kfree(dtpm_cpu);
148 }
149
150 static struct dtpm_ops dtpm_ops = {
151         .set_power_uw    = set_pd_power_limit,
152         .get_power_uw    = get_pd_power_uw,
153         .update_power_uw = update_pd_power_uw,
154         .release         = pd_release,
155 };
156
157 static int cpuhp_dtpm_cpu_offline(unsigned int cpu)
158 {
159         struct dtpm_cpu *dtpm_cpu;
160
161         dtpm_cpu = per_cpu(dtpm_per_cpu, cpu);
162         if (dtpm_cpu)
163                 dtpm_update_power(&dtpm_cpu->dtpm);
164
165         return 0;
166 }
167
168 static int cpuhp_dtpm_cpu_online(unsigned int cpu)
169 {
170         struct dtpm_cpu *dtpm_cpu;
171
172         dtpm_cpu = per_cpu(dtpm_per_cpu, cpu);
173         if (dtpm_cpu)
174                 return dtpm_update_power(&dtpm_cpu->dtpm);
175
176         return 0;
177 }
178
179 static int __dtpm_cpu_setup(int cpu, struct dtpm *parent)
180 {
181         struct dtpm_cpu *dtpm_cpu;
182         struct cpufreq_policy *policy;
183         struct em_perf_domain *pd;
184         char name[CPUFREQ_NAME_LEN];
185         int ret = -ENOMEM;
186
187         dtpm_cpu = per_cpu(dtpm_per_cpu, cpu);
188         if (dtpm_cpu)
189                 return 0;
190
191         policy = cpufreq_cpu_get(cpu);
192         if (!policy)
193                 return 0;
194
195         pd = em_cpu_get(cpu);
196         if (!pd || em_is_artificial(pd)) {
197                 ret = -EINVAL;
198                 goto release_policy;
199         }
200
201         dtpm_cpu = kzalloc(sizeof(*dtpm_cpu), GFP_KERNEL);
202         if (!dtpm_cpu) {
203                 ret = -ENOMEM;
204                 goto release_policy;
205         }
206
207         dtpm_init(&dtpm_cpu->dtpm, &dtpm_ops);
208         dtpm_cpu->cpu = cpu;
209
210         for_each_cpu(cpu, policy->related_cpus)
211                 per_cpu(dtpm_per_cpu, cpu) = dtpm_cpu;
212
213         snprintf(name, sizeof(name), "cpu%d-cpufreq", dtpm_cpu->cpu);
214
215         ret = dtpm_register(name, &dtpm_cpu->dtpm, parent);
216         if (ret)
217                 goto out_kfree_dtpm_cpu;
218
219         ret = freq_qos_add_request(&policy->constraints,
220                                    &dtpm_cpu->qos_req, FREQ_QOS_MAX,
221                                    pd->table[pd->nr_perf_states - 1].frequency);
222         if (ret)
223                 goto out_dtpm_unregister;
224
225         cpufreq_cpu_put(policy);
226         return 0;
227
228 out_dtpm_unregister:
229         dtpm_unregister(&dtpm_cpu->dtpm);
230         dtpm_cpu = NULL;
231
232 out_kfree_dtpm_cpu:
233         for_each_cpu(cpu, policy->related_cpus)
234                 per_cpu(dtpm_per_cpu, cpu) = NULL;
235         kfree(dtpm_cpu);
236
237 release_policy:
238         cpufreq_cpu_put(policy);
239         return ret;
240 }
241
242 static int dtpm_cpu_setup(struct dtpm *dtpm, struct device_node *np)
243 {
244         int cpu;
245
246         cpu = of_cpu_node_to_id(np);
247         if (cpu < 0)
248                 return 0;
249
250         return __dtpm_cpu_setup(cpu, dtpm);
251 }
252
253 static int dtpm_cpu_init(void)
254 {
255         int ret;
256
257         /*
258          * The callbacks at CPU hotplug time are calling
259          * dtpm_update_power() which in turns calls update_pd_power().
260          *
261          * The function update_pd_power() uses the online mask to
262          * figure out the power consumption limits.
263          *
264          * At CPUHP_AP_ONLINE_DYN, the CPU is present in the CPU
265          * online mask when the cpuhp_dtpm_cpu_online function is
266          * called, but the CPU is still in the online mask for the
267          * tear down callback. So the power can not be updated when
268          * the CPU is unplugged.
269          *
270          * At CPUHP_AP_DTPM_CPU_DEAD, the situation is the opposite as
271          * above. The CPU online mask is not up to date when the CPU
272          * is plugged in.
273          *
274          * For this reason, we need to call the online and offline
275          * callbacks at different moments when the CPU online mask is
276          * consistent with the power numbers we want to update.
277          */
278         ret = cpuhp_setup_state(CPUHP_AP_DTPM_CPU_DEAD, "dtpm_cpu:offline",
279                                 NULL, cpuhp_dtpm_cpu_offline);
280         if (ret < 0)
281                 return ret;
282
283         ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "dtpm_cpu:online",
284                                 cpuhp_dtpm_cpu_online, NULL);
285         if (ret < 0)
286                 return ret;
287
288         return 0;
289 }
290
291 static void dtpm_cpu_exit(void)
292 {
293         cpuhp_remove_state_nocalls(CPUHP_AP_ONLINE_DYN);
294         cpuhp_remove_state_nocalls(CPUHP_AP_DTPM_CPU_DEAD);
295 }
296
297 struct dtpm_subsys_ops dtpm_cpu_ops = {
298         .name = KBUILD_MODNAME,
299         .init = dtpm_cpu_init,
300         .exit = dtpm_cpu_exit,
301         .setup = dtpm_cpu_setup,
302 };