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 * MICROWATT_PER_MILLIWATT * 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 * 67 MICROWATT_PER_MILLIWATT * nr_cpus; 68 69 return power_limit; 70 } 71 72 static u64 scale_pd_power_uw(struct cpumask *pd_mask, u64 power) 73 { 74 unsigned long max = 0, sum_util = 0; 75 int cpu; 76 77 for_each_cpu_and(cpu, pd_mask, cpu_online_mask) { 78 79 /* 80 * The capacity is the same for all CPUs belonging to 81 * the same perf domain, so a single call to 82 * arch_scale_cpu_capacity() is enough. However, we 83 * need the CPU parameter to be initialized by the 84 * loop, so the call ends up in this block. 85 * 86 * We can initialize 'max' with a cpumask_first() call 87 * before the loop but the bits computation is not 88 * worth given the arch_scale_cpu_capacity() just 89 * returns a value where the resulting assembly code 90 * will be optimized by the compiler. 91 */ 92 max = arch_scale_cpu_capacity(cpu); 93 sum_util += sched_cpu_util(cpu, max); 94 } 95 96 /* 97 * In the improbable case where all the CPUs of the perf 98 * domain are offline, 'max' will be zero and will lead to an 99 * illegal operation with a zero division. 100 */ 101 return max ? (power * ((sum_util << 10) / max)) >> 10 : 0; 102 } 103 104 static u64 get_pd_power_uw(struct dtpm *dtpm) 105 { 106 struct dtpm_cpu *dtpm_cpu = to_dtpm_cpu(dtpm); 107 struct em_perf_domain *pd; 108 struct cpumask *pd_mask; 109 unsigned long freq; 110 int i; 111 112 pd = em_cpu_get(dtpm_cpu->cpu); 113 114 pd_mask = em_span_cpus(pd); 115 116 freq = cpufreq_quick_get(dtpm_cpu->cpu); 117 118 for (i = 0; i < pd->nr_perf_states; i++) { 119 120 if (pd->table[i].frequency < freq) 121 continue; 122 123 return scale_pd_power_uw(pd_mask, pd->table[i].power * 124 MICROWATT_PER_MILLIWATT); 125 } 126 127 return 0; 128 } 129 130 static int update_pd_power_uw(struct dtpm *dtpm) 131 { 132 struct dtpm_cpu *dtpm_cpu = to_dtpm_cpu(dtpm); 133 struct em_perf_domain *em = em_cpu_get(dtpm_cpu->cpu); 134 struct cpumask cpus; 135 int nr_cpus; 136 137 cpumask_and(&cpus, cpu_online_mask, to_cpumask(em->cpus)); 138 nr_cpus = cpumask_weight(&cpus); 139 140 dtpm->power_min = em->table[0].power; 141 dtpm->power_min *= MICROWATT_PER_MILLIWATT; 142 dtpm->power_min *= nr_cpus; 143 144 dtpm->power_max = em->table[em->nr_perf_states - 1].power; 145 dtpm->power_max *= MICROWATT_PER_MILLIWATT; 146 dtpm->power_max *= nr_cpus; 147 148 return 0; 149 } 150 151 static void pd_release(struct dtpm *dtpm) 152 { 153 struct dtpm_cpu *dtpm_cpu = to_dtpm_cpu(dtpm); 154 struct cpufreq_policy *policy; 155 156 if (freq_qos_request_active(&dtpm_cpu->qos_req)) 157 freq_qos_remove_request(&dtpm_cpu->qos_req); 158 159 policy = cpufreq_cpu_get(dtpm_cpu->cpu); 160 if (policy) { 161 for_each_cpu(dtpm_cpu->cpu, policy->related_cpus) 162 per_cpu(dtpm_per_cpu, dtpm_cpu->cpu) = NULL; 163 } 164 165 kfree(dtpm_cpu); 166 } 167 168 static struct dtpm_ops dtpm_ops = { 169 .set_power_uw = set_pd_power_limit, 170 .get_power_uw = get_pd_power_uw, 171 .update_power_uw = update_pd_power_uw, 172 .release = pd_release, 173 }; 174 175 static int cpuhp_dtpm_cpu_offline(unsigned int cpu) 176 { 177 struct dtpm_cpu *dtpm_cpu; 178 179 dtpm_cpu = per_cpu(dtpm_per_cpu, cpu); 180 if (dtpm_cpu) 181 dtpm_update_power(&dtpm_cpu->dtpm); 182 183 return 0; 184 } 185 186 static int cpuhp_dtpm_cpu_online(unsigned int cpu) 187 { 188 struct dtpm_cpu *dtpm_cpu; 189 190 dtpm_cpu = per_cpu(dtpm_per_cpu, cpu); 191 if (dtpm_cpu) 192 return dtpm_update_power(&dtpm_cpu->dtpm); 193 194 return 0; 195 } 196 197 static int __dtpm_cpu_setup(int cpu, struct dtpm *parent) 198 { 199 struct dtpm_cpu *dtpm_cpu; 200 struct cpufreq_policy *policy; 201 struct em_perf_domain *pd; 202 char name[CPUFREQ_NAME_LEN]; 203 int ret = -ENOMEM; 204 205 dtpm_cpu = per_cpu(dtpm_per_cpu, cpu); 206 if (dtpm_cpu) 207 return 0; 208 209 policy = cpufreq_cpu_get(cpu); 210 if (!policy) 211 return 0; 212 213 pd = em_cpu_get(cpu); 214 if (!pd) 215 return -EINVAL; 216 217 dtpm_cpu = kzalloc(sizeof(*dtpm_cpu), GFP_KERNEL); 218 if (!dtpm_cpu) 219 return -ENOMEM; 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 ret = freq_qos_add_request(&policy->constraints, 234 &dtpm_cpu->qos_req, FREQ_QOS_MAX, 235 pd->table[pd->nr_perf_states - 1].frequency); 236 if (ret) 237 goto out_dtpm_unregister; 238 239 return 0; 240 241 out_dtpm_unregister: 242 dtpm_unregister(&dtpm_cpu->dtpm); 243 dtpm_cpu = NULL; 244 245 out_kfree_dtpm_cpu: 246 for_each_cpu(cpu, policy->related_cpus) 247 per_cpu(dtpm_per_cpu, cpu) = NULL; 248 kfree(dtpm_cpu); 249 250 return ret; 251 } 252 253 static int dtpm_cpu_setup(struct dtpm *dtpm, struct device_node *np) 254 { 255 int cpu; 256 257 cpu = of_cpu_node_to_id(np); 258 if (cpu < 0) 259 return 0; 260 261 return __dtpm_cpu_setup(cpu, dtpm); 262 } 263 264 static int dtpm_cpu_init(void) 265 { 266 int ret; 267 268 /* 269 * The callbacks at CPU hotplug time are calling 270 * dtpm_update_power() which in turns calls update_pd_power(). 271 * 272 * The function update_pd_power() uses the online mask to 273 * figure out the power consumption limits. 274 * 275 * At CPUHP_AP_ONLINE_DYN, the CPU is present in the CPU 276 * online mask when the cpuhp_dtpm_cpu_online function is 277 * called, but the CPU is still in the online mask for the 278 * tear down callback. So the power can not be updated when 279 * the CPU is unplugged. 280 * 281 * At CPUHP_AP_DTPM_CPU_DEAD, the situation is the opposite as 282 * above. The CPU online mask is not up to date when the CPU 283 * is plugged in. 284 * 285 * For this reason, we need to call the online and offline 286 * callbacks at different moments when the CPU online mask is 287 * consistent with the power numbers we want to update. 288 */ 289 ret = cpuhp_setup_state(CPUHP_AP_DTPM_CPU_DEAD, "dtpm_cpu:offline", 290 NULL, cpuhp_dtpm_cpu_offline); 291 if (ret < 0) 292 return ret; 293 294 ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "dtpm_cpu:online", 295 cpuhp_dtpm_cpu_online, NULL); 296 if (ret < 0) 297 return ret; 298 299 return 0; 300 } 301 302 static void dtpm_cpu_exit(void) 303 { 304 cpuhp_remove_state_nocalls(CPUHP_AP_ONLINE_DYN); 305 cpuhp_remove_state_nocalls(CPUHP_AP_DTPM_CPU_DEAD); 306 } 307 308 struct dtpm_subsys_ops dtpm_cpu_ops = { 309 .name = KBUILD_MODNAME, 310 .init = dtpm_cpu_init, 311 .exit = dtpm_cpu_exit, 312 .setup = dtpm_cpu_setup, 313 }; 314