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 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 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 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_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 } 120 121 static 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 } 143 144 static 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 } 162 163 static 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 }; 169 170 static 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 } 180 181 static 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 } 191 192 static 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(sizeof(*dtpm_cpu), GFP_KERNEL); 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; 244 245 out_dtpm_unregister: 246 dtpm_unregister(&dtpm_cpu->dtpm); 247 dtpm_cpu = NULL; 248 249 out_kfree_dtpm_cpu: 250 for_each_cpu(cpu, policy->related_cpus) 251 per_cpu(dtpm_per_cpu, cpu) = NULL; 252 kfree(dtpm_cpu); 253 254 release_policy: 255 cpufreq_cpu_put(policy); 256 return ret; 257 } 258 259 static 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 } 269 270 static 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 } 307 308 static 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 } 313 314 struct 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 }; 320