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 }; 298