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
to_dtpm_cpu(struct dtpm * dtpm)36 static struct dtpm_cpu *to_dtpm_cpu(struct dtpm *dtpm)
37 {
38 return container_of(dtpm, struct dtpm_cpu, dtpm);
39 }
40
set_pd_power_limit(struct dtpm * dtpm,u64 power_limit)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
scale_pd_power_uw(struct cpumask * pd_mask,u64 power)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
get_pd_power_uw(struct dtpm * dtpm)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
update_pd_power_uw(struct dtpm * dtpm)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
pd_release(struct dtpm * dtpm)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
cpuhp_dtpm_cpu_offline(unsigned int cpu)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
cpuhp_dtpm_cpu_online(unsigned int cpu)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
__dtpm_cpu_setup(int cpu,struct dtpm * parent)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 < 0)
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
dtpm_cpu_setup(struct dtpm * dtpm,struct device_node * np)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
dtpm_cpu_init(void)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
dtpm_cpu_exit(void)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 };
303