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 scale_pd_power_uw(struct cpumask *pd_mask, u64 power) 72 { 73 unsigned long max = 0, sum_util = 0; 74 int cpu; 75 76 for_each_cpu_and(cpu, pd_mask, cpu_online_mask) { 77 78 /* 79 * The capacity is the same for all CPUs belonging to 80 * the same perf domain, so a single call to 81 * arch_scale_cpu_capacity() is enough. However, we 82 * need the CPU parameter to be initialized by the 83 * loop, so the call ends up in this block. 84 * 85 * We can initialize 'max' with a cpumask_first() call 86 * before the loop but the bits computation is not 87 * worth given the arch_scale_cpu_capacity() just 88 * returns a value where the resulting assembly code 89 * will be optimized by the compiler. 90 */ 91 max = arch_scale_cpu_capacity(cpu); 92 sum_util += sched_cpu_util(cpu, max); 93 } 94 95 /* 96 * In the improbable case where all the CPUs of the perf 97 * domain are offline, 'max' will be zero and will lead to an 98 * illegal operation with a zero division. 99 */ 100 return max ? (power * ((sum_util << 10) / max)) >> 10 : 0; 101 } 102 103 static u64 get_pd_power_uw(struct dtpm *dtpm) 104 { 105 struct dtpm_cpu *dtpm_cpu = to_dtpm_cpu(dtpm); 106 struct em_perf_domain *pd; 107 struct cpumask *pd_mask; 108 unsigned long freq; 109 int i; 110 111 pd = em_cpu_get(dtpm_cpu->cpu); 112 113 pd_mask = em_span_cpus(pd); 114 115 freq = cpufreq_quick_get(dtpm_cpu->cpu); 116 117 for (i = 0; i < pd->nr_perf_states; i++) { 118 119 if (pd->table[i].frequency < freq) 120 continue; 121 122 return scale_pd_power_uw(pd_mask, pd->table[i].power * 123 MICROWATT_PER_MILLIWATT); 124 } 125 126 return 0; 127 } 128 129 static int update_pd_power_uw(struct dtpm *dtpm) 130 { 131 struct dtpm_cpu *dtpm_cpu = to_dtpm_cpu(dtpm); 132 struct em_perf_domain *em = em_cpu_get(dtpm_cpu->cpu); 133 struct cpumask cpus; 134 int nr_cpus; 135 136 cpumask_and(&cpus, cpu_online_mask, to_cpumask(em->cpus)); 137 nr_cpus = cpumask_weight(&cpus); 138 139 dtpm->power_min = em->table[0].power; 140 dtpm->power_min *= MICROWATT_PER_MILLIWATT; 141 dtpm->power_min *= nr_cpus; 142 143 dtpm->power_max = em->table[em->nr_perf_states - 1].power; 144 dtpm->power_max *= MICROWATT_PER_MILLIWATT; 145 dtpm->power_max *= nr_cpus; 146 147 return 0; 148 } 149 150 static void pd_release(struct dtpm *dtpm) 151 { 152 struct dtpm_cpu *dtpm_cpu = to_dtpm_cpu(dtpm); 153 154 if (freq_qos_request_active(&dtpm_cpu->qos_req)) 155 freq_qos_remove_request(&dtpm_cpu->qos_req); 156 157 kfree(dtpm_cpu); 158 } 159 160 static struct dtpm_ops dtpm_ops = { 161 .set_power_uw = set_pd_power_limit, 162 .get_power_uw = get_pd_power_uw, 163 .update_power_uw = update_pd_power_uw, 164 .release = pd_release, 165 }; 166 167 static int cpuhp_dtpm_cpu_offline(unsigned int cpu) 168 { 169 struct em_perf_domain *pd; 170 struct dtpm_cpu *dtpm_cpu; 171 172 pd = em_cpu_get(cpu); 173 if (!pd) 174 return -EINVAL; 175 176 dtpm_cpu = per_cpu(dtpm_per_cpu, cpu); 177 178 return dtpm_update_power(&dtpm_cpu->dtpm); 179 } 180 181 static int cpuhp_dtpm_cpu_online(unsigned int cpu) 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 policy = cpufreq_cpu_get(cpu); 190 if (!policy) 191 return 0; 192 193 pd = em_cpu_get(cpu); 194 if (!pd) 195 return -EINVAL; 196 197 dtpm_cpu = per_cpu(dtpm_per_cpu, cpu); 198 if (dtpm_cpu) 199 return dtpm_update_power(&dtpm_cpu->dtpm); 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, NULL); 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 __init dtpm_cpu_init(void) 238 { 239 int ret; 240 241 /* 242 * The callbacks at CPU hotplug time are calling 243 * dtpm_update_power() which in turns calls update_pd_power(). 244 * 245 * The function update_pd_power() uses the online mask to 246 * figure out the power consumption limits. 247 * 248 * At CPUHP_AP_ONLINE_DYN, the CPU is present in the CPU 249 * online mask when the cpuhp_dtpm_cpu_online function is 250 * called, but the CPU is still in the online mask for the 251 * tear down callback. So the power can not be updated when 252 * the CPU is unplugged. 253 * 254 * At CPUHP_AP_DTPM_CPU_DEAD, the situation is the opposite as 255 * above. The CPU online mask is not up to date when the CPU 256 * is plugged in. 257 * 258 * For this reason, we need to call the online and offline 259 * callbacks at different moments when the CPU online mask is 260 * consistent with the power numbers we want to update. 261 */ 262 ret = cpuhp_setup_state(CPUHP_AP_DTPM_CPU_DEAD, "dtpm_cpu:offline", 263 NULL, cpuhp_dtpm_cpu_offline); 264 if (ret < 0) 265 return ret; 266 267 ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "dtpm_cpu:online", 268 cpuhp_dtpm_cpu_online, NULL); 269 if (ret < 0) 270 return ret; 271 272 return 0; 273 } 274 275 DTPM_DECLARE(dtpm_cpu, dtpm_cpu_init); 276