Merge tag 'pm-5.20-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
[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 #include <linux/units.h>
28
29 struct dtpm_cpu {
30         struct dtpm dtpm;
31         struct freq_qos_request qos_req;
32         int cpu;
33 };
34
35 static DEFINE_PER_CPU(struct dtpm_cpu *, dtpm_per_cpu);
36
37 static struct dtpm_cpu *to_dtpm_cpu(struct dtpm *dtpm)
38 {
39         return container_of(dtpm, struct dtpm_cpu, dtpm);
40 }
41
42 static u64 set_pd_power_limit(struct dtpm *dtpm, u64 power_limit)
43 {
44         struct dtpm_cpu *dtpm_cpu = to_dtpm_cpu(dtpm);
45         struct em_perf_domain *pd = em_cpu_get(dtpm_cpu->cpu);
46         struct cpumask cpus;
47         unsigned long freq;
48         u64 power;
49         int i, nr_cpus;
50
51         cpumask_and(&cpus, cpu_online_mask, to_cpumask(pd->cpus));
52         nr_cpus = cpumask_weight(&cpus);
53
54         for (i = 0; i < pd->nr_perf_states; i++) {
55
56                 power = pd->table[i].power * nr_cpus;
57
58                 if (power > power_limit)
59                         break;
60         }
61
62         freq = pd->table[i - 1].frequency;
63
64         freq_qos_update_request(&dtpm_cpu->qos_req, freq);
65
66         power_limit = pd->table[i - 1].power * nr_cpus;
67
68         return power_limit;
69 }
70
71 static u64 scale_pd_power_uw(struct cpumask *pd_mask, u64 power)
72 {
73         unsigned long max, sum_util = 0;
74         int cpu;
75
76         /*
77          * The capacity is the same for all CPUs belonging to
78          * the same perf domain.
79          */
80         max = arch_scale_cpu_capacity(cpumask_first(pd_mask));
81
82         for_each_cpu_and(cpu, pd_mask, cpu_online_mask)
83                 sum_util += sched_cpu_util(cpu);
84
85         return (power * ((sum_util << 10) / max)) >> 10;
86 }
87
88 static u64 get_pd_power_uw(struct dtpm *dtpm)
89 {
90         struct dtpm_cpu *dtpm_cpu = to_dtpm_cpu(dtpm);
91         struct em_perf_domain *pd;
92         struct cpumask *pd_mask;
93         unsigned long freq;
94         int i;
95
96         pd = em_cpu_get(dtpm_cpu->cpu);
97
98         pd_mask = em_span_cpus(pd);
99
100         freq = cpufreq_quick_get(dtpm_cpu->cpu);
101
102         for (i = 0; i < pd->nr_perf_states; i++) {
103
104                 if (pd->table[i].frequency < freq)
105                         continue;
106
107                 return scale_pd_power_uw(pd_mask, pd->table[i].power *
108                                          MICROWATT_PER_MILLIWATT);
109         }
110
111         return 0;
112 }
113
114 static int update_pd_power_uw(struct dtpm *dtpm)
115 {
116         struct dtpm_cpu *dtpm_cpu = to_dtpm_cpu(dtpm);
117         struct em_perf_domain *em = em_cpu_get(dtpm_cpu->cpu);
118         struct cpumask cpus;
119         int nr_cpus;
120
121         cpumask_and(&cpus, cpu_online_mask, to_cpumask(em->cpus));
122         nr_cpus = cpumask_weight(&cpus);
123
124         dtpm->power_min = em->table[0].power;
125         dtpm->power_min *= MICROWATT_PER_MILLIWATT;
126         dtpm->power_min *= nr_cpus;
127
128         dtpm->power_max = em->table[em->nr_perf_states - 1].power;
129         dtpm->power_max *= MICROWATT_PER_MILLIWATT;
130         dtpm->power_max *= nr_cpus;
131
132         return 0;
133 }
134
135 static void pd_release(struct dtpm *dtpm)
136 {
137         struct dtpm_cpu *dtpm_cpu = to_dtpm_cpu(dtpm);
138         struct cpufreq_policy *policy;
139
140         if (freq_qos_request_active(&dtpm_cpu->qos_req))
141                 freq_qos_remove_request(&dtpm_cpu->qos_req);
142
143         policy = cpufreq_cpu_get(dtpm_cpu->cpu);
144         if (policy) {
145                 for_each_cpu(dtpm_cpu->cpu, policy->related_cpus)
146                         per_cpu(dtpm_per_cpu, dtpm_cpu->cpu) = NULL;
147         }
148         
149         kfree(dtpm_cpu);
150 }
151
152 static struct dtpm_ops dtpm_ops = {
153         .set_power_uw    = set_pd_power_limit,
154         .get_power_uw    = get_pd_power_uw,
155         .update_power_uw = update_pd_power_uw,
156         .release         = pd_release,
157 };
158
159 static int cpuhp_dtpm_cpu_offline(unsigned int cpu)
160 {
161         struct dtpm_cpu *dtpm_cpu;
162
163         dtpm_cpu = per_cpu(dtpm_per_cpu, cpu);
164         if (dtpm_cpu)
165                 dtpm_update_power(&dtpm_cpu->dtpm);
166
167         return 0;
168 }
169
170 static int cpuhp_dtpm_cpu_online(unsigned int cpu)
171 {
172         struct dtpm_cpu *dtpm_cpu;
173
174         dtpm_cpu = per_cpu(dtpm_per_cpu, cpu);
175         if (dtpm_cpu)
176                 return dtpm_update_power(&dtpm_cpu->dtpm);
177
178         return 0;
179 }
180
181 static int __dtpm_cpu_setup(int cpu, struct dtpm *parent)
182 {
183         struct dtpm_cpu *dtpm_cpu;
184         struct cpufreq_policy *policy;
185         struct em_perf_domain *pd;
186         char name[CPUFREQ_NAME_LEN];
187         int ret = -ENOMEM;
188
189         dtpm_cpu = per_cpu(dtpm_per_cpu, cpu);
190         if (dtpm_cpu)
191                 return 0;
192
193         policy = cpufreq_cpu_get(cpu);
194         if (!policy)
195                 return 0;
196
197         pd = em_cpu_get(cpu);
198         if (!pd || em_is_artificial(pd))
199                 return -EINVAL;
200
201         dtpm_cpu = kzalloc(sizeof(*dtpm_cpu), GFP_KERNEL);
202         if (!dtpm_cpu)
203                 return -ENOMEM;
204
205         dtpm_init(&dtpm_cpu->dtpm, &dtpm_ops);
206         dtpm_cpu->cpu = cpu;
207
208         for_each_cpu(cpu, policy->related_cpus)
209                 per_cpu(dtpm_per_cpu, cpu) = dtpm_cpu;
210
211         snprintf(name, sizeof(name), "cpu%d-cpufreq", dtpm_cpu->cpu);
212
213         ret = dtpm_register(name, &dtpm_cpu->dtpm, parent);
214         if (ret)
215                 goto out_kfree_dtpm_cpu;
216
217         ret = freq_qos_add_request(&policy->constraints,
218                                    &dtpm_cpu->qos_req, FREQ_QOS_MAX,
219                                    pd->table[pd->nr_perf_states - 1].frequency);
220         if (ret)
221                 goto out_dtpm_unregister;
222
223         return 0;
224
225 out_dtpm_unregister:
226         dtpm_unregister(&dtpm_cpu->dtpm);
227         dtpm_cpu = NULL;
228
229 out_kfree_dtpm_cpu:
230         for_each_cpu(cpu, policy->related_cpus)
231                 per_cpu(dtpm_per_cpu, cpu) = NULL;
232         kfree(dtpm_cpu);
233
234         return ret;
235 }
236
237 static int dtpm_cpu_setup(struct dtpm *dtpm, struct device_node *np)
238 {
239         int cpu;
240
241         cpu = of_cpu_node_to_id(np);
242         if (cpu < 0)
243                 return 0;
244
245         return __dtpm_cpu_setup(cpu, dtpm);
246 }
247
248 static int dtpm_cpu_init(void)
249 {
250         int ret;
251
252         /*
253          * The callbacks at CPU hotplug time are calling
254          * dtpm_update_power() which in turns calls update_pd_power().
255          *
256          * The function update_pd_power() uses the online mask to
257          * figure out the power consumption limits.
258          *
259          * At CPUHP_AP_ONLINE_DYN, the CPU is present in the CPU
260          * online mask when the cpuhp_dtpm_cpu_online function is
261          * called, but the CPU is still in the online mask for the
262          * tear down callback. So the power can not be updated when
263          * the CPU is unplugged.
264          *
265          * At CPUHP_AP_DTPM_CPU_DEAD, the situation is the opposite as
266          * above. The CPU online mask is not up to date when the CPU
267          * is plugged in.
268          *
269          * For this reason, we need to call the online and offline
270          * callbacks at different moments when the CPU online mask is
271          * consistent with the power numbers we want to update.
272          */
273         ret = cpuhp_setup_state(CPUHP_AP_DTPM_CPU_DEAD, "dtpm_cpu:offline",
274                                 NULL, cpuhp_dtpm_cpu_offline);
275         if (ret < 0)
276                 return ret;
277
278         ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "dtpm_cpu:online",
279                                 cpuhp_dtpm_cpu_online, NULL);
280         if (ret < 0)
281                 return ret;
282
283         return 0;
284 }
285
286 static void dtpm_cpu_exit(void)
287 {
288         cpuhp_remove_state_nocalls(CPUHP_AP_ONLINE_DYN);
289         cpuhp_remove_state_nocalls(CPUHP_AP_DTPM_CPU_DEAD);
290 }
291
292 struct dtpm_subsys_ops dtpm_cpu_ops = {
293         .name = KBUILD_MODNAME,
294         .init = dtpm_cpu_init,
295         .exit = dtpm_cpu_exit,
296         .setup = dtpm_cpu_setup,
297 };