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/cpu.h> 11 #include <linux/cpufreq.h> 12 #include <linux/device.h> 13 #include <linux/of.h> 14 #include <linux/slab.h> 15 #include <linux/string.h> 16 #include <linux/sched/topology.h> 17 #include <linux/cpuset.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 DEFINE_PER_CPU(unsigned long, cpu_scale) = SCHED_CAPACITY_SCALE; 34 35 void topology_set_cpu_scale(unsigned int cpu, unsigned long capacity) 36 { 37 per_cpu(cpu_scale, cpu) = capacity; 38 } 39 40 static ssize_t cpu_capacity_show(struct device *dev, 41 struct device_attribute *attr, 42 char *buf) 43 { 44 struct cpu *cpu = container_of(dev, struct cpu, dev); 45 46 return sprintf(buf, "%lu\n", topology_get_cpu_scale(cpu->dev.id)); 47 } 48 49 static void update_topology_flags_workfn(struct work_struct *work); 50 static DECLARE_WORK(update_topology_flags_work, update_topology_flags_workfn); 51 52 static DEVICE_ATTR_RO(cpu_capacity); 53 54 static int register_cpu_capacity_sysctl(void) 55 { 56 int i; 57 struct device *cpu; 58 59 for_each_possible_cpu(i) { 60 cpu = get_cpu_device(i); 61 if (!cpu) { 62 pr_err("%s: too early to get CPU%d device!\n", 63 __func__, i); 64 continue; 65 } 66 device_create_file(cpu, &dev_attr_cpu_capacity); 67 } 68 69 return 0; 70 } 71 subsys_initcall(register_cpu_capacity_sysctl); 72 73 static int update_topology; 74 75 int topology_update_cpu_topology(void) 76 { 77 return update_topology; 78 } 79 80 /* 81 * Updating the sched_domains can't be done directly from cpufreq callbacks 82 * due to locking, so queue the work for later. 83 */ 84 static void update_topology_flags_workfn(struct work_struct *work) 85 { 86 update_topology = 1; 87 rebuild_sched_domains(); 88 pr_debug("sched_domain hierarchy rebuilt, flags updated\n"); 89 update_topology = 0; 90 } 91 92 static u32 capacity_scale; 93 static u32 *raw_capacity; 94 95 static int free_raw_capacity(void) 96 { 97 kfree(raw_capacity); 98 raw_capacity = NULL; 99 100 return 0; 101 } 102 103 void topology_normalize_cpu_scale(void) 104 { 105 u64 capacity; 106 int cpu; 107 108 if (!raw_capacity) 109 return; 110 111 pr_debug("cpu_capacity: capacity_scale=%u\n", capacity_scale); 112 for_each_possible_cpu(cpu) { 113 pr_debug("cpu_capacity: cpu=%d raw_capacity=%u\n", 114 cpu, raw_capacity[cpu]); 115 capacity = (raw_capacity[cpu] << SCHED_CAPACITY_SHIFT) 116 / capacity_scale; 117 topology_set_cpu_scale(cpu, capacity); 118 pr_debug("cpu_capacity: CPU%d cpu_capacity=%lu\n", 119 cpu, topology_get_cpu_scale(cpu)); 120 } 121 } 122 123 bool __init topology_parse_cpu_capacity(struct device_node *cpu_node, int cpu) 124 { 125 static bool cap_parsing_failed; 126 int ret; 127 u32 cpu_capacity; 128 129 if (cap_parsing_failed) 130 return false; 131 132 ret = of_property_read_u32(cpu_node, "capacity-dmips-mhz", 133 &cpu_capacity); 134 if (!ret) { 135 if (!raw_capacity) { 136 raw_capacity = kcalloc(num_possible_cpus(), 137 sizeof(*raw_capacity), 138 GFP_KERNEL); 139 if (!raw_capacity) { 140 cap_parsing_failed = true; 141 return false; 142 } 143 } 144 capacity_scale = max(cpu_capacity, capacity_scale); 145 raw_capacity[cpu] = cpu_capacity; 146 pr_debug("cpu_capacity: %pOF cpu_capacity=%u (raw)\n", 147 cpu_node, raw_capacity[cpu]); 148 } else { 149 if (raw_capacity) { 150 pr_err("cpu_capacity: missing %pOF raw capacity\n", 151 cpu_node); 152 pr_err("cpu_capacity: partial information: fallback to 1024 for all CPUs\n"); 153 } 154 cap_parsing_failed = true; 155 free_raw_capacity(); 156 } 157 158 return !ret; 159 } 160 161 #ifdef CONFIG_CPU_FREQ 162 static cpumask_var_t cpus_to_visit; 163 static void parsing_done_workfn(struct work_struct *work); 164 static DECLARE_WORK(parsing_done_work, parsing_done_workfn); 165 166 static int 167 init_cpu_capacity_callback(struct notifier_block *nb, 168 unsigned long val, 169 void *data) 170 { 171 struct cpufreq_policy *policy = data; 172 int cpu; 173 174 if (!raw_capacity) 175 return 0; 176 177 if (val != CPUFREQ_NOTIFY) 178 return 0; 179 180 pr_debug("cpu_capacity: init cpu capacity for CPUs [%*pbl] (to_visit=%*pbl)\n", 181 cpumask_pr_args(policy->related_cpus), 182 cpumask_pr_args(cpus_to_visit)); 183 184 cpumask_andnot(cpus_to_visit, cpus_to_visit, policy->related_cpus); 185 186 for_each_cpu(cpu, policy->related_cpus) { 187 raw_capacity[cpu] = topology_get_cpu_scale(cpu) * 188 policy->cpuinfo.max_freq / 1000UL; 189 capacity_scale = max(raw_capacity[cpu], capacity_scale); 190 } 191 192 if (cpumask_empty(cpus_to_visit)) { 193 topology_normalize_cpu_scale(); 194 schedule_work(&update_topology_flags_work); 195 free_raw_capacity(); 196 pr_debug("cpu_capacity: parsing done\n"); 197 schedule_work(&parsing_done_work); 198 } 199 200 return 0; 201 } 202 203 static struct notifier_block init_cpu_capacity_notifier = { 204 .notifier_call = init_cpu_capacity_callback, 205 }; 206 207 static int __init register_cpufreq_notifier(void) 208 { 209 int ret; 210 211 /* 212 * on ACPI-based systems we need to use the default cpu capacity 213 * until we have the necessary code to parse the cpu capacity, so 214 * skip registering cpufreq notifier. 215 */ 216 if (!acpi_disabled || !raw_capacity) 217 return -EINVAL; 218 219 if (!alloc_cpumask_var(&cpus_to_visit, GFP_KERNEL)) 220 return -ENOMEM; 221 222 cpumask_copy(cpus_to_visit, cpu_possible_mask); 223 224 ret = cpufreq_register_notifier(&init_cpu_capacity_notifier, 225 CPUFREQ_POLICY_NOTIFIER); 226 227 if (ret) 228 free_cpumask_var(cpus_to_visit); 229 230 return ret; 231 } 232 core_initcall(register_cpufreq_notifier); 233 234 static void parsing_done_workfn(struct work_struct *work) 235 { 236 cpufreq_unregister_notifier(&init_cpu_capacity_notifier, 237 CPUFREQ_POLICY_NOTIFIER); 238 free_cpumask_var(cpus_to_visit); 239 } 240 241 #else 242 core_initcall(free_raw_capacity); 243 #endif 244