1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Arch specific cpu topology information 4 * 5 * Copyright (C) 2016, ARM Ltd. 6 * Written by: Juri Lelli, ARM Ltd. 7 */ 8 9 #include <linux/acpi.h> 10 #include <linux/arch_topology.h> 11 #include <linux/cpu.h> 12 #include <linux/cpufreq.h> 13 #include <linux/device.h> 14 #include <linux/of.h> 15 #include <linux/slab.h> 16 #include <linux/string.h> 17 #include <linux/sched/topology.h> 18 19 DEFINE_PER_CPU(unsigned long, freq_scale) = SCHED_CAPACITY_SCALE; 20 21 void arch_set_freq_scale(struct cpumask *cpus, unsigned long cur_freq, 22 unsigned long max_freq) 23 { 24 unsigned long scale; 25 int i; 26 27 scale = (cur_freq << SCHED_CAPACITY_SHIFT) / max_freq; 28 29 for_each_cpu(i, cpus) 30 per_cpu(freq_scale, i) = scale; 31 } 32 33 static DEFINE_MUTEX(cpu_scale_mutex); 34 DEFINE_PER_CPU(unsigned long, cpu_scale) = SCHED_CAPACITY_SCALE; 35 36 void topology_set_cpu_scale(unsigned int cpu, unsigned long capacity) 37 { 38 per_cpu(cpu_scale, cpu) = capacity; 39 } 40 41 static ssize_t cpu_capacity_show(struct device *dev, 42 struct device_attribute *attr, 43 char *buf) 44 { 45 struct cpu *cpu = container_of(dev, struct cpu, dev); 46 47 return sprintf(buf, "%lu\n", topology_get_cpu_scale(NULL, cpu->dev.id)); 48 } 49 50 static ssize_t cpu_capacity_store(struct device *dev, 51 struct device_attribute *attr, 52 const char *buf, 53 size_t count) 54 { 55 struct cpu *cpu = container_of(dev, struct cpu, dev); 56 int this_cpu = cpu->dev.id; 57 int i; 58 unsigned long new_capacity; 59 ssize_t ret; 60 61 if (!count) 62 return 0; 63 64 ret = kstrtoul(buf, 0, &new_capacity); 65 if (ret) 66 return ret; 67 if (new_capacity > SCHED_CAPACITY_SCALE) 68 return -EINVAL; 69 70 mutex_lock(&cpu_scale_mutex); 71 for_each_cpu(i, &cpu_topology[this_cpu].core_sibling) 72 topology_set_cpu_scale(i, new_capacity); 73 mutex_unlock(&cpu_scale_mutex); 74 75 return count; 76 } 77 78 static DEVICE_ATTR_RW(cpu_capacity); 79 80 static int register_cpu_capacity_sysctl(void) 81 { 82 int i; 83 struct device *cpu; 84 85 for_each_possible_cpu(i) { 86 cpu = get_cpu_device(i); 87 if (!cpu) { 88 pr_err("%s: too early to get CPU%d device!\n", 89 __func__, i); 90 continue; 91 } 92 device_create_file(cpu, &dev_attr_cpu_capacity); 93 } 94 95 return 0; 96 } 97 subsys_initcall(register_cpu_capacity_sysctl); 98 99 static u32 capacity_scale; 100 static u32 *raw_capacity; 101 102 static int free_raw_capacity(void) 103 { 104 kfree(raw_capacity); 105 raw_capacity = NULL; 106 107 return 0; 108 } 109 110 void topology_normalize_cpu_scale(void) 111 { 112 u64 capacity; 113 int cpu; 114 115 if (!raw_capacity) 116 return; 117 118 pr_debug("cpu_capacity: capacity_scale=%u\n", capacity_scale); 119 mutex_lock(&cpu_scale_mutex); 120 for_each_possible_cpu(cpu) { 121 pr_debug("cpu_capacity: cpu=%d raw_capacity=%u\n", 122 cpu, raw_capacity[cpu]); 123 capacity = (raw_capacity[cpu] << SCHED_CAPACITY_SHIFT) 124 / capacity_scale; 125 topology_set_cpu_scale(cpu, capacity); 126 pr_debug("cpu_capacity: CPU%d cpu_capacity=%lu\n", 127 cpu, topology_get_cpu_scale(NULL, cpu)); 128 } 129 mutex_unlock(&cpu_scale_mutex); 130 } 131 132 bool __init topology_parse_cpu_capacity(struct device_node *cpu_node, int cpu) 133 { 134 static bool cap_parsing_failed; 135 int ret; 136 u32 cpu_capacity; 137 138 if (cap_parsing_failed) 139 return false; 140 141 ret = of_property_read_u32(cpu_node, "capacity-dmips-mhz", 142 &cpu_capacity); 143 if (!ret) { 144 if (!raw_capacity) { 145 raw_capacity = kcalloc(num_possible_cpus(), 146 sizeof(*raw_capacity), 147 GFP_KERNEL); 148 if (!raw_capacity) { 149 pr_err("cpu_capacity: failed to allocate memory for raw capacities\n"); 150 cap_parsing_failed = true; 151 return false; 152 } 153 } 154 capacity_scale = max(cpu_capacity, capacity_scale); 155 raw_capacity[cpu] = cpu_capacity; 156 pr_debug("cpu_capacity: %pOF cpu_capacity=%u (raw)\n", 157 cpu_node, raw_capacity[cpu]); 158 } else { 159 if (raw_capacity) { 160 pr_err("cpu_capacity: missing %pOF raw capacity\n", 161 cpu_node); 162 pr_err("cpu_capacity: partial information: fallback to 1024 for all CPUs\n"); 163 } 164 cap_parsing_failed = true; 165 free_raw_capacity(); 166 } 167 168 return !ret; 169 } 170 171 #ifdef CONFIG_CPU_FREQ 172 static cpumask_var_t cpus_to_visit; 173 static void parsing_done_workfn(struct work_struct *work); 174 static DECLARE_WORK(parsing_done_work, parsing_done_workfn); 175 176 static int 177 init_cpu_capacity_callback(struct notifier_block *nb, 178 unsigned long val, 179 void *data) 180 { 181 struct cpufreq_policy *policy = data; 182 int cpu; 183 184 if (!raw_capacity) 185 return 0; 186 187 if (val != CPUFREQ_NOTIFY) 188 return 0; 189 190 pr_debug("cpu_capacity: init cpu capacity for CPUs [%*pbl] (to_visit=%*pbl)\n", 191 cpumask_pr_args(policy->related_cpus), 192 cpumask_pr_args(cpus_to_visit)); 193 194 cpumask_andnot(cpus_to_visit, cpus_to_visit, policy->related_cpus); 195 196 for_each_cpu(cpu, policy->related_cpus) { 197 raw_capacity[cpu] = topology_get_cpu_scale(NULL, cpu) * 198 policy->cpuinfo.max_freq / 1000UL; 199 capacity_scale = max(raw_capacity[cpu], capacity_scale); 200 } 201 202 if (cpumask_empty(cpus_to_visit)) { 203 topology_normalize_cpu_scale(); 204 free_raw_capacity(); 205 pr_debug("cpu_capacity: parsing done\n"); 206 schedule_work(&parsing_done_work); 207 } 208 209 return 0; 210 } 211 212 static struct notifier_block init_cpu_capacity_notifier = { 213 .notifier_call = init_cpu_capacity_callback, 214 }; 215 216 static int __init register_cpufreq_notifier(void) 217 { 218 int ret; 219 220 /* 221 * on ACPI-based systems we need to use the default cpu capacity 222 * until we have the necessary code to parse the cpu capacity, so 223 * skip registering cpufreq notifier. 224 */ 225 if (!acpi_disabled || !raw_capacity) 226 return -EINVAL; 227 228 if (!alloc_cpumask_var(&cpus_to_visit, GFP_KERNEL)) { 229 pr_err("cpu_capacity: failed to allocate memory for cpus_to_visit\n"); 230 return -ENOMEM; 231 } 232 233 cpumask_copy(cpus_to_visit, cpu_possible_mask); 234 235 ret = cpufreq_register_notifier(&init_cpu_capacity_notifier, 236 CPUFREQ_POLICY_NOTIFIER); 237 238 if (ret) 239 free_cpumask_var(cpus_to_visit); 240 241 return ret; 242 } 243 core_initcall(register_cpufreq_notifier); 244 245 static void parsing_done_workfn(struct work_struct *work) 246 { 247 cpufreq_unregister_notifier(&init_cpu_capacity_notifier, 248 CPUFREQ_POLICY_NOTIFIER); 249 free_cpumask_var(cpus_to_visit); 250 } 251 252 #else 253 core_initcall(free_raw_capacity); 254 #endif 255