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/pm_qos.h> 25 #include <linux/slab.h> 26 #include <linux/units.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 * MICROWATT_PER_MILLIWATT * 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 * 66 MICROWATT_PER_MILLIWATT * nr_cpus; 67 68 return power_limit; 69 } 70 71 static u64 get_pd_power_uw(struct dtpm *dtpm) 72 { 73 struct dtpm_cpu *dtpm_cpu = to_dtpm_cpu(dtpm); 74 struct em_perf_domain *pd; 75 struct cpumask cpus; 76 unsigned long freq; 77 int i, nr_cpus; 78 79 pd = em_cpu_get(dtpm_cpu->cpu); 80 freq = cpufreq_quick_get(dtpm_cpu->cpu); 81 82 cpumask_and(&cpus, cpu_online_mask, to_cpumask(pd->cpus)); 83 nr_cpus = cpumask_weight(&cpus); 84 85 for (i = 0; i < pd->nr_perf_states; i++) { 86 87 if (pd->table[i].frequency < freq) 88 continue; 89 90 return pd->table[i].power * 91 MICROWATT_PER_MILLIWATT * nr_cpus; 92 } 93 94 return 0; 95 } 96 97 static int update_pd_power_uw(struct dtpm *dtpm) 98 { 99 struct dtpm_cpu *dtpm_cpu = to_dtpm_cpu(dtpm); 100 struct em_perf_domain *em = em_cpu_get(dtpm_cpu->cpu); 101 struct cpumask cpus; 102 int nr_cpus; 103 104 cpumask_and(&cpus, cpu_online_mask, to_cpumask(em->cpus)); 105 nr_cpus = cpumask_weight(&cpus); 106 107 dtpm->power_min = em->table[0].power; 108 dtpm->power_min *= MICROWATT_PER_MILLIWATT; 109 dtpm->power_min *= nr_cpus; 110 111 dtpm->power_max = em->table[em->nr_perf_states - 1].power; 112 dtpm->power_max *= MICROWATT_PER_MILLIWATT; 113 dtpm->power_max *= nr_cpus; 114 115 return 0; 116 } 117 118 static void pd_release(struct dtpm *dtpm) 119 { 120 struct dtpm_cpu *dtpm_cpu = to_dtpm_cpu(dtpm); 121 122 if (freq_qos_request_active(&dtpm_cpu->qos_req)) 123 freq_qos_remove_request(&dtpm_cpu->qos_req); 124 125 kfree(dtpm_cpu); 126 } 127 128 static struct dtpm_ops dtpm_ops = { 129 .set_power_uw = set_pd_power_limit, 130 .get_power_uw = get_pd_power_uw, 131 .update_power_uw = update_pd_power_uw, 132 .release = pd_release, 133 }; 134 135 static int cpuhp_dtpm_cpu_offline(unsigned int cpu) 136 { 137 struct em_perf_domain *pd; 138 struct dtpm_cpu *dtpm_cpu; 139 140 pd = em_cpu_get(cpu); 141 if (!pd) 142 return -EINVAL; 143 144 dtpm_cpu = per_cpu(dtpm_per_cpu, cpu); 145 146 return dtpm_update_power(&dtpm_cpu->dtpm); 147 } 148 149 static int cpuhp_dtpm_cpu_online(unsigned int cpu) 150 { 151 struct dtpm_cpu *dtpm_cpu; 152 struct cpufreq_policy *policy; 153 struct em_perf_domain *pd; 154 char name[CPUFREQ_NAME_LEN]; 155 int ret = -ENOMEM; 156 157 policy = cpufreq_cpu_get(cpu); 158 if (!policy) 159 return 0; 160 161 pd = em_cpu_get(cpu); 162 if (!pd) 163 return -EINVAL; 164 165 dtpm_cpu = per_cpu(dtpm_per_cpu, cpu); 166 if (dtpm_cpu) 167 return dtpm_update_power(&dtpm_cpu->dtpm); 168 169 dtpm_cpu = kzalloc(sizeof(*dtpm_cpu), GFP_KERNEL); 170 if (!dtpm_cpu) 171 return -ENOMEM; 172 173 dtpm_init(&dtpm_cpu->dtpm, &dtpm_ops); 174 dtpm_cpu->cpu = cpu; 175 176 for_each_cpu(cpu, policy->related_cpus) 177 per_cpu(dtpm_per_cpu, cpu) = dtpm_cpu; 178 179 snprintf(name, sizeof(name), "cpu%d-cpufreq", dtpm_cpu->cpu); 180 181 ret = dtpm_register(name, &dtpm_cpu->dtpm, NULL); 182 if (ret) 183 goto out_kfree_dtpm_cpu; 184 185 ret = freq_qos_add_request(&policy->constraints, 186 &dtpm_cpu->qos_req, FREQ_QOS_MAX, 187 pd->table[pd->nr_perf_states - 1].frequency); 188 if (ret) 189 goto out_dtpm_unregister; 190 191 return 0; 192 193 out_dtpm_unregister: 194 dtpm_unregister(&dtpm_cpu->dtpm); 195 dtpm_cpu = NULL; 196 197 out_kfree_dtpm_cpu: 198 for_each_cpu(cpu, policy->related_cpus) 199 per_cpu(dtpm_per_cpu, cpu) = NULL; 200 kfree(dtpm_cpu); 201 202 return ret; 203 } 204 205 static int __init dtpm_cpu_init(void) 206 { 207 int ret; 208 209 /* 210 * The callbacks at CPU hotplug time are calling 211 * dtpm_update_power() which in turns calls update_pd_power(). 212 * 213 * The function update_pd_power() uses the online mask to 214 * figure out the power consumption limits. 215 * 216 * At CPUHP_AP_ONLINE_DYN, the CPU is present in the CPU 217 * online mask when the cpuhp_dtpm_cpu_online function is 218 * called, but the CPU is still in the online mask for the 219 * tear down callback. So the power can not be updated when 220 * the CPU is unplugged. 221 * 222 * At CPUHP_AP_DTPM_CPU_DEAD, the situation is the opposite as 223 * above. The CPU online mask is not up to date when the CPU 224 * is plugged in. 225 * 226 * For this reason, we need to call the online and offline 227 * callbacks at different moments when the CPU online mask is 228 * consistent with the power numbers we want to update. 229 */ 230 ret = cpuhp_setup_state(CPUHP_AP_DTPM_CPU_DEAD, "dtpm_cpu:offline", 231 NULL, cpuhp_dtpm_cpu_offline); 232 if (ret < 0) 233 return ret; 234 235 ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "dtpm_cpu:online", 236 cpuhp_dtpm_cpu_online, NULL); 237 if (ret < 0) 238 return ret; 239 240 return 0; 241 } 242 243 DTPM_DECLARE(dtpm_cpu, dtpm_cpu_init); 244