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 static DEFINE_PER_CPU(struct dtpm *, dtpm_per_cpu); 29 30 struct dtpm_cpu { 31 struct freq_qos_request qos_req; 32 int cpu; 33 }; 34 35 static u64 set_pd_power_limit(struct dtpm *dtpm, u64 power_limit) 36 { 37 struct dtpm_cpu *dtpm_cpu = dtpm->private; 38 struct em_perf_domain *pd = em_cpu_get(dtpm_cpu->cpu); 39 struct cpumask cpus; 40 unsigned long freq; 41 u64 power; 42 int i, nr_cpus; 43 44 cpumask_and(&cpus, cpu_online_mask, to_cpumask(pd->cpus)); 45 nr_cpus = cpumask_weight(&cpus); 46 47 for (i = 0; i < pd->nr_perf_states; i++) { 48 49 power = pd->table[i].power * MICROWATT_PER_MILLIWATT * nr_cpus; 50 51 if (power > power_limit) 52 break; 53 } 54 55 freq = pd->table[i - 1].frequency; 56 57 freq_qos_update_request(&dtpm_cpu->qos_req, freq); 58 59 power_limit = pd->table[i - 1].power * 60 MICROWATT_PER_MILLIWATT * nr_cpus; 61 62 return power_limit; 63 } 64 65 static u64 get_pd_power_uw(struct dtpm *dtpm) 66 { 67 struct dtpm_cpu *dtpm_cpu = dtpm->private; 68 struct em_perf_domain *pd; 69 struct cpumask cpus; 70 unsigned long freq; 71 int i, nr_cpus; 72 73 pd = em_cpu_get(dtpm_cpu->cpu); 74 freq = cpufreq_quick_get(dtpm_cpu->cpu); 75 76 cpumask_and(&cpus, cpu_online_mask, to_cpumask(pd->cpus)); 77 nr_cpus = cpumask_weight(&cpus); 78 79 for (i = 0; i < pd->nr_perf_states; i++) { 80 81 if (pd->table[i].frequency < freq) 82 continue; 83 84 return pd->table[i].power * 85 MICROWATT_PER_MILLIWATT * nr_cpus; 86 } 87 88 return 0; 89 } 90 91 static int update_pd_power_uw(struct dtpm *dtpm) 92 { 93 struct dtpm_cpu *dtpm_cpu = dtpm->private; 94 struct em_perf_domain *em = em_cpu_get(dtpm_cpu->cpu); 95 struct cpumask cpus; 96 int nr_cpus; 97 98 cpumask_and(&cpus, cpu_online_mask, to_cpumask(em->cpus)); 99 nr_cpus = cpumask_weight(&cpus); 100 101 dtpm->power_min = em->table[0].power; 102 dtpm->power_min *= MICROWATT_PER_MILLIWATT; 103 dtpm->power_min *= nr_cpus; 104 105 dtpm->power_max = em->table[em->nr_perf_states - 1].power; 106 dtpm->power_max *= MICROWATT_PER_MILLIWATT; 107 dtpm->power_max *= nr_cpus; 108 109 return 0; 110 } 111 112 static void pd_release(struct dtpm *dtpm) 113 { 114 struct dtpm_cpu *dtpm_cpu = dtpm->private; 115 116 if (freq_qos_request_active(&dtpm_cpu->qos_req)) 117 freq_qos_remove_request(&dtpm_cpu->qos_req); 118 119 kfree(dtpm_cpu); 120 } 121 122 static struct dtpm_ops dtpm_ops = { 123 .set_power_uw = set_pd_power_limit, 124 .get_power_uw = get_pd_power_uw, 125 .update_power_uw = update_pd_power_uw, 126 .release = pd_release, 127 }; 128 129 static int cpuhp_dtpm_cpu_offline(unsigned int cpu) 130 { 131 struct em_perf_domain *pd; 132 struct dtpm *dtpm; 133 134 pd = em_cpu_get(cpu); 135 if (!pd) 136 return -EINVAL; 137 138 dtpm = per_cpu(dtpm_per_cpu, cpu); 139 140 return dtpm_update_power(dtpm); 141 } 142 143 static int cpuhp_dtpm_cpu_online(unsigned int cpu) 144 { 145 struct dtpm *dtpm; 146 struct dtpm_cpu *dtpm_cpu; 147 struct cpufreq_policy *policy; 148 struct em_perf_domain *pd; 149 char name[CPUFREQ_NAME_LEN]; 150 int ret = -ENOMEM; 151 152 policy = cpufreq_cpu_get(cpu); 153 if (!policy) 154 return 0; 155 156 pd = em_cpu_get(cpu); 157 if (!pd) 158 return -EINVAL; 159 160 dtpm = per_cpu(dtpm_per_cpu, cpu); 161 if (dtpm) 162 return dtpm_update_power(dtpm); 163 164 dtpm = dtpm_alloc(&dtpm_ops); 165 if (!dtpm) 166 return -EINVAL; 167 168 dtpm_cpu = kzalloc(sizeof(*dtpm_cpu), GFP_KERNEL); 169 if (!dtpm_cpu) 170 goto out_kfree_dtpm; 171 172 dtpm->private = dtpm_cpu; 173 dtpm_cpu->cpu = cpu; 174 175 for_each_cpu(cpu, policy->related_cpus) 176 per_cpu(dtpm_per_cpu, cpu) = dtpm; 177 178 snprintf(name, sizeof(name), "cpu%d-cpufreq", dtpm_cpu->cpu); 179 180 ret = dtpm_register(name, dtpm, NULL); 181 if (ret) 182 goto out_kfree_dtpm_cpu; 183 184 ret = freq_qos_add_request(&policy->constraints, 185 &dtpm_cpu->qos_req, FREQ_QOS_MAX, 186 pd->table[pd->nr_perf_states - 1].frequency); 187 if (ret) 188 goto out_dtpm_unregister; 189 190 return 0; 191 192 out_dtpm_unregister: 193 dtpm_unregister(dtpm); 194 dtpm_cpu = NULL; 195 dtpm = 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 out_kfree_dtpm: 203 kfree(dtpm); 204 return ret; 205 } 206 207 static int __init dtpm_cpu_init(void) 208 { 209 int ret; 210 211 /* 212 * The callbacks at CPU hotplug time are calling 213 * dtpm_update_power() which in turns calls update_pd_power(). 214 * 215 * The function update_pd_power() uses the online mask to 216 * figure out the power consumption limits. 217 * 218 * At CPUHP_AP_ONLINE_DYN, the CPU is present in the CPU 219 * online mask when the cpuhp_dtpm_cpu_online function is 220 * called, but the CPU is still in the online mask for the 221 * tear down callback. So the power can not be updated when 222 * the CPU is unplugged. 223 * 224 * At CPUHP_AP_DTPM_CPU_DEAD, the situation is the opposite as 225 * above. The CPU online mask is not up to date when the CPU 226 * is plugged in. 227 * 228 * For this reason, we need to call the online and offline 229 * callbacks at different moments when the CPU online mask is 230 * consistent with the power numbers we want to update. 231 */ 232 ret = cpuhp_setup_state(CPUHP_AP_DTPM_CPU_DEAD, "dtpm_cpu:offline", 233 NULL, cpuhp_dtpm_cpu_offline); 234 if (ret < 0) 235 return ret; 236 237 ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "dtpm_cpu:online", 238 cpuhp_dtpm_cpu_online, NULL); 239 if (ret < 0) 240 return ret; 241 242 return 0; 243 } 244 245 DTPM_DECLARE(dtpm_cpu, dtpm_cpu_init); 246