318 lines · c
1// SPDX-License-Identifier: GPL-2.0-only2/*3 * Copyright 2020 Linaro Limited4 *5 * Author: Daniel Lezcano <daniel.lezcano@linaro.org>6 *7 * The DTPM CPU is based on the energy model. It hooks the CPU in the8 * DTPM tree which in turns update the power number by propagating the9 * power number from the CPU energy model information to the parents.10 *11 * The association between the power and the performance state, allows12 * to set the power of the CPU at the OPP granularity.13 *14 * The CPU hotplug is supported and the power numbers will be updated15 * if a CPU is hot plugged / unplugged.16 */17#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt18 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 to78 * 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);99 100 pd_mask = em_span_cpus(pd);101 102 freq = cpufreq_quick_get(dtpm_cpu->cpu);103 104 rcu_read_lock();105 table = em_perf_state_from_pd(pd);106 for (i = 0; i < pd->nr_perf_states; i++) {107 108 if (table[i].frequency < freq)109 continue;110 111 power = scale_pd_power_uw(pd_mask, table[i].power);112 break;113 }114 rcu_read_unlock();115 116 return power;117}118 119static int update_pd_power_uw(struct dtpm *dtpm)120{121 struct dtpm_cpu *dtpm_cpu = to_dtpm_cpu(dtpm);122 struct em_perf_domain *em = em_cpu_get(dtpm_cpu->cpu);123 struct em_perf_state *table;124 int nr_cpus;125 126 nr_cpus = cpumask_weight_and(cpu_online_mask, to_cpumask(em->cpus));127 128 rcu_read_lock();129 table = em_perf_state_from_pd(em);130 131 dtpm->power_min = table[0].power;132 dtpm->power_min *= nr_cpus;133 134 dtpm->power_max = table[em->nr_perf_states - 1].power;135 dtpm->power_max *= nr_cpus;136 137 rcu_read_unlock();138 139 return 0;140}141 142static void pd_release(struct dtpm *dtpm)143{144 struct dtpm_cpu *dtpm_cpu = to_dtpm_cpu(dtpm);145 struct cpufreq_policy *policy;146 147 if (freq_qos_request_active(&dtpm_cpu->qos_req))148 freq_qos_remove_request(&dtpm_cpu->qos_req);149 150 policy = cpufreq_cpu_get(dtpm_cpu->cpu);151 if (policy) {152 for_each_cpu(dtpm_cpu->cpu, policy->related_cpus)153 per_cpu(dtpm_per_cpu, dtpm_cpu->cpu) = NULL;154 155 cpufreq_cpu_put(policy);156 }157 158 kfree(dtpm_cpu);159}160 161static struct dtpm_ops dtpm_ops = {162 .set_power_uw = set_pd_power_limit,163 .get_power_uw = get_pd_power_uw,164 .update_power_uw = update_pd_power_uw,165 .release = pd_release,166};167 168static int cpuhp_dtpm_cpu_offline(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 dtpm_update_power(&dtpm_cpu->dtpm);175 176 return 0;177}178 179static int cpuhp_dtpm_cpu_online(unsigned int cpu)180{181 struct dtpm_cpu *dtpm_cpu;182 183 dtpm_cpu = per_cpu(dtpm_per_cpu, cpu);184 if (dtpm_cpu)185 return dtpm_update_power(&dtpm_cpu->dtpm);186 187 return 0;188}189 190static int __dtpm_cpu_setup(int cpu, struct dtpm *parent)191{192 struct dtpm_cpu *dtpm_cpu;193 struct cpufreq_policy *policy;194 struct em_perf_state *table;195 struct em_perf_domain *pd;196 char name[CPUFREQ_NAME_LEN];197 int ret = -ENOMEM;198 199 dtpm_cpu = per_cpu(dtpm_per_cpu, cpu);200 if (dtpm_cpu)201 return 0;202 203 policy = cpufreq_cpu_get(cpu);204 if (!policy)205 return 0;206 207 pd = em_cpu_get(cpu);208 if (!pd || em_is_artificial(pd)) {209 ret = -EINVAL;210 goto release_policy;211 }212 213 dtpm_cpu = kzalloc(sizeof(*dtpm_cpu), GFP_KERNEL);214 if (!dtpm_cpu) {215 ret = -ENOMEM;216 goto release_policy;217 }218 219 dtpm_init(&dtpm_cpu->dtpm, &dtpm_ops);220 dtpm_cpu->cpu = cpu;221 222 for_each_cpu(cpu, policy->related_cpus)223 per_cpu(dtpm_per_cpu, cpu) = dtpm_cpu;224 225 snprintf(name, sizeof(name), "cpu%d-cpufreq", dtpm_cpu->cpu);226 227 ret = dtpm_register(name, &dtpm_cpu->dtpm, parent);228 if (ret)229 goto out_kfree_dtpm_cpu;230 231 rcu_read_lock();232 table = em_perf_state_from_pd(pd);233 ret = freq_qos_add_request(&policy->constraints,234 &dtpm_cpu->qos_req, FREQ_QOS_MAX,235 table[pd->nr_perf_states - 1].frequency);236 rcu_read_unlock();237 if (ret < 0)238 goto out_dtpm_unregister;239 240 cpufreq_cpu_put(policy);241 return 0;242 243out_dtpm_unregister:244 dtpm_unregister(&dtpm_cpu->dtpm);245 dtpm_cpu = NULL;246 247out_kfree_dtpm_cpu:248 for_each_cpu(cpu, policy->related_cpus)249 per_cpu(dtpm_per_cpu, cpu) = NULL;250 kfree(dtpm_cpu);251 252release_policy:253 cpufreq_cpu_put(policy);254 return ret;255}256 257static int dtpm_cpu_setup(struct dtpm *dtpm, struct device_node *np)258{259 int cpu;260 261 cpu = of_cpu_node_to_id(np);262 if (cpu < 0)263 return 0;264 265 return __dtpm_cpu_setup(cpu, dtpm);266}267 268static int dtpm_cpu_init(void)269{270 int ret;271 272 /*273 * The callbacks at CPU hotplug time are calling274 * dtpm_update_power() which in turns calls update_pd_power().275 *276 * The function update_pd_power() uses the online mask to277 * figure out the power consumption limits.278 *279 * At CPUHP_AP_ONLINE_DYN, the CPU is present in the CPU280 * online mask when the cpuhp_dtpm_cpu_online function is281 * called, but the CPU is still in the online mask for the282 * tear down callback. So the power can not be updated when283 * the CPU is unplugged.284 *285 * At CPUHP_AP_DTPM_CPU_DEAD, the situation is the opposite as286 * above. The CPU online mask is not up to date when the CPU287 * is plugged in.288 *289 * For this reason, we need to call the online and offline290 * callbacks at different moments when the CPU online mask is291 * consistent with the power numbers we want to update.292 */293 ret = cpuhp_setup_state(CPUHP_AP_DTPM_CPU_DEAD, "dtpm_cpu:offline",294 NULL, cpuhp_dtpm_cpu_offline);295 if (ret < 0)296 return ret;297 298 ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "dtpm_cpu:online",299 cpuhp_dtpm_cpu_online, NULL);300 if (ret < 0)301 return ret;302 303 return 0;304}305 306static void dtpm_cpu_exit(void)307{308 cpuhp_remove_state_nocalls(CPUHP_AP_ONLINE_DYN);309 cpuhp_remove_state_nocalls(CPUHP_AP_DTPM_CPU_DEAD);310}311 312struct dtpm_subsys_ops dtpm_cpu_ops = {313 .name = KBUILD_MODNAME,314 .init = dtpm_cpu_init,315 .exit = dtpm_cpu_exit,316 .setup = dtpm_cpu_setup,317};318