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 #include <linux/cpuset.h> 19 20 DEFINE_PER_CPU(unsigned long, freq_scale) = SCHED_CAPACITY_SCALE; 21 22 void arch_set_freq_scale(struct cpumask *cpus, unsigned long cur_freq, 23 unsigned long max_freq) 24 { 25 unsigned long scale; 26 int i; 27 28 scale = (cur_freq << SCHED_CAPACITY_SHIFT) / max_freq; 29 30 for_each_cpu(i, cpus) 31 per_cpu(freq_scale, i) = scale; 32 } 33 34 static DEFINE_MUTEX(cpu_scale_mutex); 35 DEFINE_PER_CPU(unsigned long, cpu_scale) = SCHED_CAPACITY_SCALE; 36 37 void topology_set_cpu_scale(unsigned int cpu, unsigned long capacity) 38 { 39 per_cpu(cpu_scale, cpu) = capacity; 40 } 41 42 static ssize_t cpu_capacity_show(struct device *dev, 43 struct device_attribute *attr, 44 char *buf) 45 { 46 struct cpu *cpu = container_of(dev, struct cpu, dev); 47 48 return sprintf(buf, "%lu\n", topology_get_cpu_scale(NULL, cpu->dev.id)); 49 } 50 51 static void update_topology_flags_workfn(struct work_struct *work); 52 static DECLARE_WORK(update_topology_flags_work, update_topology_flags_workfn); 53 54 static ssize_t cpu_capacity_store(struct device *dev, 55 struct device_attribute *attr, 56 const char *buf, 57 size_t count) 58 { 59 struct cpu *cpu = container_of(dev, struct cpu, dev); 60 int this_cpu = cpu->dev.id; 61 int i; 62 unsigned long new_capacity; 63 ssize_t ret; 64 65 if (!count) 66 return 0; 67 68 ret = kstrtoul(buf, 0, &new_capacity); 69 if (ret) 70 return ret; 71 if (new_capacity > SCHED_CAPACITY_SCALE) 72 return -EINVAL; 73 74 mutex_lock(&cpu_scale_mutex); 75 for_each_cpu(i, &cpu_topology[this_cpu].core_sibling) 76 topology_set_cpu_scale(i, new_capacity); 77 mutex_unlock(&cpu_scale_mutex); 78 79 schedule_work(&update_topology_flags_work); 80 81 return count; 82 } 83 84 static DEVICE_ATTR_RW(cpu_capacity); 85 86 static int register_cpu_capacity_sysctl(void) 87 { 88 int i; 89 struct device *cpu; 90 91 for_each_possible_cpu(i) { 92 cpu = get_cpu_device(i); 93 if (!cpu) { 94 pr_err("%s: too early to get CPU%d device!\n", 95 __func__, i); 96 continue; 97 } 98 device_create_file(cpu, &dev_attr_cpu_capacity); 99 } 100 101 return 0; 102 } 103 subsys_initcall(register_cpu_capacity_sysctl); 104 105 static int update_topology; 106 107 int topology_update_cpu_topology(void) 108 { 109 return update_topology; 110 } 111 112 /* 113 * Updating the sched_domains can't be done directly from cpufreq callbacks 114 * due to locking, so queue the work for later. 115 */ 116 static void update_topology_flags_workfn(struct work_struct *work) 117 { 118 update_topology = 1; 119 rebuild_sched_domains(); 120 pr_debug("sched_domain hierarchy rebuilt, flags updated\n"); 121 update_topology = 0; 122 } 123 124 static u32 capacity_scale; 125 static u32 *raw_capacity; 126 127 static int free_raw_capacity(void) 128 { 129 kfree(raw_capacity); 130 raw_capacity = NULL; 131 132 return 0; 133 } 134 135 void topology_normalize_cpu_scale(void) 136 { 137 u64 capacity; 138 int cpu; 139 140 if (!raw_capacity) 141 return; 142 143 pr_debug("cpu_capacity: capacity_scale=%u\n", capacity_scale); 144 mutex_lock(&cpu_scale_mutex); 145 for_each_possible_cpu(cpu) { 146 pr_debug("cpu_capacity: cpu=%d raw_capacity=%u\n", 147 cpu, raw_capacity[cpu]); 148 capacity = (raw_capacity[cpu] << SCHED_CAPACITY_SHIFT) 149 / capacity_scale; 150 topology_set_cpu_scale(cpu, capacity); 151 pr_debug("cpu_capacity: CPU%d cpu_capacity=%lu\n", 152 cpu, topology_get_cpu_scale(NULL, cpu)); 153 } 154 mutex_unlock(&cpu_scale_mutex); 155 } 156 157 bool __init topology_parse_cpu_capacity(struct device_node *cpu_node, int cpu) 158 { 159 static bool cap_parsing_failed; 160 int ret; 161 u32 cpu_capacity; 162 163 if (cap_parsing_failed) 164 return false; 165 166 ret = of_property_read_u32(cpu_node, "capacity-dmips-mhz", 167 &cpu_capacity); 168 if (!ret) { 169 if (!raw_capacity) { 170 raw_capacity = kcalloc(num_possible_cpus(), 171 sizeof(*raw_capacity), 172 GFP_KERNEL); 173 if (!raw_capacity) { 174 pr_err("cpu_capacity: failed to allocate memory for raw capacities\n"); 175 cap_parsing_failed = true; 176 return false; 177 } 178 } 179 capacity_scale = max(cpu_capacity, capacity_scale); 180 raw_capacity[cpu] = cpu_capacity; 181 pr_debug("cpu_capacity: %pOF cpu_capacity=%u (raw)\n", 182 cpu_node, raw_capacity[cpu]); 183 } else { 184 if (raw_capacity) { 185 pr_err("cpu_capacity: missing %pOF raw capacity\n", 186 cpu_node); 187 pr_err("cpu_capacity: partial information: fallback to 1024 for all CPUs\n"); 188 } 189 cap_parsing_failed = true; 190 free_raw_capacity(); 191 } 192 193 return !ret; 194 } 195 196 #ifdef CONFIG_CPU_FREQ 197 static cpumask_var_t cpus_to_visit; 198 static void parsing_done_workfn(struct work_struct *work); 199 static DECLARE_WORK(parsing_done_work, parsing_done_workfn); 200 201 static int 202 init_cpu_capacity_callback(struct notifier_block *nb, 203 unsigned long val, 204 void *data) 205 { 206 struct cpufreq_policy *policy = data; 207 int cpu; 208 209 if (!raw_capacity) 210 return 0; 211 212 if (val != CPUFREQ_NOTIFY) 213 return 0; 214 215 pr_debug("cpu_capacity: init cpu capacity for CPUs [%*pbl] (to_visit=%*pbl)\n", 216 cpumask_pr_args(policy->related_cpus), 217 cpumask_pr_args(cpus_to_visit)); 218 219 cpumask_andnot(cpus_to_visit, cpus_to_visit, policy->related_cpus); 220 221 for_each_cpu(cpu, policy->related_cpus) { 222 raw_capacity[cpu] = topology_get_cpu_scale(NULL, cpu) * 223 policy->cpuinfo.max_freq / 1000UL; 224 capacity_scale = max(raw_capacity[cpu], capacity_scale); 225 } 226 227 if (cpumask_empty(cpus_to_visit)) { 228 topology_normalize_cpu_scale(); 229 schedule_work(&update_topology_flags_work); 230 free_raw_capacity(); 231 pr_debug("cpu_capacity: parsing done\n"); 232 schedule_work(&parsing_done_work); 233 } 234 235 return 0; 236 } 237 238 static struct notifier_block init_cpu_capacity_notifier = { 239 .notifier_call = init_cpu_capacity_callback, 240 }; 241 242 static int __init register_cpufreq_notifier(void) 243 { 244 int ret; 245 246 /* 247 * on ACPI-based systems we need to use the default cpu capacity 248 * until we have the necessary code to parse the cpu capacity, so 249 * skip registering cpufreq notifier. 250 */ 251 if (!acpi_disabled || !raw_capacity) 252 return -EINVAL; 253 254 if (!alloc_cpumask_var(&cpus_to_visit, GFP_KERNEL)) { 255 pr_err("cpu_capacity: failed to allocate memory for cpus_to_visit\n"); 256 return -ENOMEM; 257 } 258 259 cpumask_copy(cpus_to_visit, cpu_possible_mask); 260 261 ret = cpufreq_register_notifier(&init_cpu_capacity_notifier, 262 CPUFREQ_POLICY_NOTIFIER); 263 264 if (ret) 265 free_cpumask_var(cpus_to_visit); 266 267 return ret; 268 } 269 core_initcall(register_cpufreq_notifier); 270 271 static void parsing_done_workfn(struct work_struct *work) 272 { 273 cpufreq_unregister_notifier(&init_cpu_capacity_notifier, 274 CPUFREQ_POLICY_NOTIFIER); 275 free_cpumask_var(cpus_to_visit); 276 } 277 278 #else 279 core_initcall(free_raw_capacity); 280 #endif 281