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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright 2020 Linaro Limited
4 *
5 * Author: Daniel Lezcano <[email protected]>
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
28struct dtpm_cpu {
29 struct dtpm dtpm;
30 struct freq_qos_request qos_req;
31 int cpu;
32};
33
34static DEFINE_PER_CPU(struct dtpm_cpu *, dtpm_per_cpu);
35
36static struct dtpm_cpu *to_dtpm_cpu(struct dtpm *dtpm)
37{
38 return container_of(dtpm, struct dtpm_cpu, dtpm);
39}
40
41static 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 em_perf_state *table;
46 unsigned long freq;
47 u64 power;
48 int i, nr_cpus;
49
50 nr_cpus = cpumask_weight_and(cpu_online_mask, to_cpumask(pd->cpus));
51
52 rcu_read_lock();
53 table = em_perf_state_from_pd(pd);
54 for (i = 0; i < pd->nr_perf_states; i++) {
55
56 power = table[i].power * nr_cpus;
57
58 if (power > power_limit)
59 break;
60 }
61
62 freq = table[i - 1].frequency;
63 power_limit = table[i - 1].power * nr_cpus;
64 rcu_read_unlock();
65
66 freq_qos_update_request(&dtpm_cpu->qos_req, freq);
67
68 return power_limit;
69}
70
71static 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
88static u64 get_pd_power_uw(struct dtpm *dtpm)
89{
90 struct dtpm_cpu *dtpm_cpu = to_dtpm_cpu(dtpm);
91 struct em_perf_state *table;
92 struct em_perf_domain *pd;
93 struct cpumask *pd_mask;
94 unsigned long freq;
95 u64 power = 0;
96 int i;
97
98 pd = em_cpu_get(dtpm_cpu->cpu);
99 if (!pd)
100 return 0;
101
102 pd_mask = em_span_cpus(pd);
103
104 freq = cpufreq_quick_get(dtpm_cpu->cpu);
105
106 rcu_read_lock();
107 table = em_perf_state_from_pd(pd);
108 for (i = 0; i < pd->nr_perf_states; i++) {
109
110 if (table[i].frequency < freq)
111 continue;
112
113 power = scale_pd_power_uw(pd_mask, table[i].power);
114 break;
115 }
116 rcu_read_unlock();
117
118 return power;
119}
120
121static int update_pd_power_uw(struct dtpm *dtpm)
122{
123 struct dtpm_cpu *dtpm_cpu = to_dtpm_cpu(dtpm);
124 struct em_perf_domain *em = em_cpu_get(dtpm_cpu->cpu);
125 struct em_perf_state *table;
126 int nr_cpus;
127
128 nr_cpus = cpumask_weight_and(cpu_online_mask, to_cpumask(em->cpus));
129
130 rcu_read_lock();
131 table = em_perf_state_from_pd(em);
132
133 dtpm->power_min = table[0].power;
134 dtpm->power_min *= nr_cpus;
135
136 dtpm->power_max = table[em->nr_perf_states - 1].power;
137 dtpm->power_max *= nr_cpus;
138
139 rcu_read_unlock();
140
141 return 0;
142}
143
144static void pd_release(struct dtpm *dtpm)
145{
146 struct dtpm_cpu *dtpm_cpu = to_dtpm_cpu(dtpm);
147 struct cpufreq_policy *policy;
148
149 if (freq_qos_request_active(&dtpm_cpu->qos_req))
150 freq_qos_remove_request(&dtpm_cpu->qos_req);
151
152 policy = cpufreq_cpu_get(dtpm_cpu->cpu);
153 if (policy) {
154 for_each_cpu(dtpm_cpu->cpu, policy->related_cpus)
155 per_cpu(dtpm_per_cpu, dtpm_cpu->cpu) = NULL;
156
157 cpufreq_cpu_put(policy);
158 }
159
160 kfree(dtpm_cpu);
161}
162
163static struct dtpm_ops dtpm_ops = {
164 .set_power_uw = set_pd_power_limit,
165 .get_power_uw = get_pd_power_uw,
166 .update_power_uw = update_pd_power_uw,
167 .release = pd_release,
168};
169
170static int cpuhp_dtpm_cpu_offline(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 dtpm_update_power(&dtpm_cpu->dtpm);
177
178 return 0;
179}
180
181static int cpuhp_dtpm_cpu_online(unsigned int cpu)
182{
183 struct dtpm_cpu *dtpm_cpu;
184
185 dtpm_cpu = per_cpu(dtpm_per_cpu, cpu);
186 if (dtpm_cpu)
187 return dtpm_update_power(&dtpm_cpu->dtpm);
188
189 return 0;
190}
191
192static int __dtpm_cpu_setup(int cpu, struct dtpm *parent)
193{
194 struct dtpm_cpu *dtpm_cpu;
195 struct cpufreq_policy *policy;
196 struct em_perf_state *table;
197 struct em_perf_domain *pd;
198 char name[CPUFREQ_NAME_LEN];
199 int ret = -ENOMEM;
200
201 dtpm_cpu = per_cpu(dtpm_per_cpu, cpu);
202 if (dtpm_cpu)
203 return 0;
204
205 policy = cpufreq_cpu_get(cpu);
206 if (!policy)
207 return 0;
208
209 pd = em_cpu_get(cpu);
210 if (!pd || em_is_artificial(pd)) {
211 ret = -EINVAL;
212 goto release_policy;
213 }
214
215 dtpm_cpu = kzalloc_obj(*dtpm_cpu);
216 if (!dtpm_cpu) {
217 ret = -ENOMEM;
218 goto release_policy;
219 }
220
221 dtpm_init(&dtpm_cpu->dtpm, &dtpm_ops);
222 dtpm_cpu->cpu = cpu;
223
224 for_each_cpu(cpu, policy->related_cpus)
225 per_cpu(dtpm_per_cpu, cpu) = dtpm_cpu;
226
227 snprintf(name, sizeof(name), "cpu%d-cpufreq", dtpm_cpu->cpu);
228
229 ret = dtpm_register(name, &dtpm_cpu->dtpm, parent);
230 if (ret)
231 goto out_kfree_dtpm_cpu;
232
233 rcu_read_lock();
234 table = em_perf_state_from_pd(pd);
235 ret = freq_qos_add_request(&policy->constraints,
236 &dtpm_cpu->qos_req, FREQ_QOS_MAX,
237 table[pd->nr_perf_states - 1].frequency);
238 rcu_read_unlock();
239 if (ret < 0)
240 goto out_dtpm_unregister;
241
242 cpufreq_cpu_put(policy);
243 return 0;
244
245out_dtpm_unregister:
246 dtpm_unregister(&dtpm_cpu->dtpm);
247 dtpm_cpu = NULL;
248
249out_kfree_dtpm_cpu:
250 for_each_cpu(cpu, policy->related_cpus)
251 per_cpu(dtpm_per_cpu, cpu) = NULL;
252 kfree(dtpm_cpu);
253
254release_policy:
255 cpufreq_cpu_put(policy);
256 return ret;
257}
258
259static int dtpm_cpu_setup(struct dtpm *dtpm, struct device_node *np)
260{
261 int cpu;
262
263 cpu = of_cpu_node_to_id(np);
264 if (cpu < 0)
265 return 0;
266
267 return __dtpm_cpu_setup(cpu, dtpm);
268}
269
270static int dtpm_cpu_init(void)
271{
272 int ret;
273
274 /*
275 * The callbacks at CPU hotplug time are calling
276 * dtpm_update_power() which in turns calls update_pd_power().
277 *
278 * The function update_pd_power() uses the online mask to
279 * figure out the power consumption limits.
280 *
281 * At CPUHP_AP_ONLINE_DYN, the CPU is present in the CPU
282 * online mask when the cpuhp_dtpm_cpu_online function is
283 * called, but the CPU is still in the online mask for the
284 * tear down callback. So the power can not be updated when
285 * the CPU is unplugged.
286 *
287 * At CPUHP_AP_DTPM_CPU_DEAD, the situation is the opposite as
288 * above. The CPU online mask is not up to date when the CPU
289 * is plugged in.
290 *
291 * For this reason, we need to call the online and offline
292 * callbacks at different moments when the CPU online mask is
293 * consistent with the power numbers we want to update.
294 */
295 ret = cpuhp_setup_state(CPUHP_AP_DTPM_CPU_DEAD, "dtpm_cpu:offline",
296 NULL, cpuhp_dtpm_cpu_offline);
297 if (ret < 0)
298 return ret;
299
300 ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "dtpm_cpu:online",
301 cpuhp_dtpm_cpu_online, NULL);
302 if (ret < 0)
303 return ret;
304
305 return 0;
306}
307
308static void dtpm_cpu_exit(void)
309{
310 cpuhp_remove_state_nocalls(CPUHP_AP_ONLINE_DYN);
311 cpuhp_remove_state_nocalls(CPUHP_AP_DTPM_CPU_DEAD);
312}
313
314struct dtpm_subsys_ops dtpm_cpu_ops = {
315 .name = KBUILD_MODNAME,
316 .init = dtpm_cpu_init,
317 .exit = dtpm_cpu_exit,
318 .setup = dtpm_cpu_setup,
319};