1 /* 2 * Arch specific cpu topology information 3 * 4 * Copyright (C) 2016, ARM Ltd. 5 * Written by: Juri Lelli, ARM Ltd. 6 * 7 * This file is subject to the terms and conditions of the GNU General Public 8 * License. See the file "COPYING" in the main directory of this archive 9 * for more details. 10 * 11 * Released under the GPLv2 only. 12 * SPDX-License-Identifier: GPL-2.0 13 */ 14 15 #include <linux/acpi.h> 16 #include <linux/arch_topology.h> 17 #include <linux/cpu.h> 18 #include <linux/cpufreq.h> 19 #include <linux/device.h> 20 #include <linux/of.h> 21 #include <linux/slab.h> 22 #include <linux/string.h> 23 #include <linux/sched/topology.h> 24 25 DEFINE_PER_CPU(unsigned long, freq_scale) = SCHED_CAPACITY_SCALE; 26 27 void arch_set_freq_scale(struct cpumask *cpus, unsigned long cur_freq, 28 unsigned long max_freq) 29 { 30 unsigned long scale; 31 int i; 32 33 scale = (cur_freq << SCHED_CAPACITY_SHIFT) / max_freq; 34 35 for_each_cpu(i, cpus) 36 per_cpu(freq_scale, i) = scale; 37 } 38 39 static DEFINE_MUTEX(cpu_scale_mutex); 40 DEFINE_PER_CPU(unsigned long, cpu_scale) = SCHED_CAPACITY_SCALE; 41 42 void topology_set_cpu_scale(unsigned int cpu, unsigned long capacity) 43 { 44 per_cpu(cpu_scale, cpu) = capacity; 45 } 46 47 static ssize_t cpu_capacity_show(struct device *dev, 48 struct device_attribute *attr, 49 char *buf) 50 { 51 struct cpu *cpu = container_of(dev, struct cpu, dev); 52 53 return sprintf(buf, "%lu\n", topology_get_cpu_scale(NULL, cpu->dev.id)); 54 } 55 56 static ssize_t cpu_capacity_store(struct device *dev, 57 struct device_attribute *attr, 58 const char *buf, 59 size_t count) 60 { 61 struct cpu *cpu = container_of(dev, struct cpu, dev); 62 int this_cpu = cpu->dev.id; 63 int i; 64 unsigned long new_capacity; 65 ssize_t ret; 66 67 if (!count) 68 return 0; 69 70 ret = kstrtoul(buf, 0, &new_capacity); 71 if (ret) 72 return ret; 73 if (new_capacity > SCHED_CAPACITY_SCALE) 74 return -EINVAL; 75 76 mutex_lock(&cpu_scale_mutex); 77 for_each_cpu(i, &cpu_topology[this_cpu].core_sibling) 78 topology_set_cpu_scale(i, new_capacity); 79 mutex_unlock(&cpu_scale_mutex); 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 u32 capacity_scale; 106 static u32 *raw_capacity; 107 108 static int free_raw_capacity(void) 109 { 110 kfree(raw_capacity); 111 raw_capacity = NULL; 112 113 return 0; 114 } 115 116 void topology_normalize_cpu_scale(void) 117 { 118 u64 capacity; 119 int cpu; 120 121 if (!raw_capacity) 122 return; 123 124 pr_debug("cpu_capacity: capacity_scale=%u\n", capacity_scale); 125 mutex_lock(&cpu_scale_mutex); 126 for_each_possible_cpu(cpu) { 127 pr_debug("cpu_capacity: cpu=%d raw_capacity=%u\n", 128 cpu, raw_capacity[cpu]); 129 capacity = (raw_capacity[cpu] << SCHED_CAPACITY_SHIFT) 130 / capacity_scale; 131 topology_set_cpu_scale(cpu, capacity); 132 pr_debug("cpu_capacity: CPU%d cpu_capacity=%lu\n", 133 cpu, topology_get_cpu_scale(NULL, cpu)); 134 } 135 mutex_unlock(&cpu_scale_mutex); 136 } 137 138 bool __init topology_parse_cpu_capacity(struct device_node *cpu_node, int cpu) 139 { 140 static bool cap_parsing_failed; 141 int ret; 142 u32 cpu_capacity; 143 144 if (cap_parsing_failed) 145 return false; 146 147 ret = of_property_read_u32(cpu_node, "capacity-dmips-mhz", 148 &cpu_capacity); 149 if (!ret) { 150 if (!raw_capacity) { 151 raw_capacity = kcalloc(num_possible_cpus(), 152 sizeof(*raw_capacity), 153 GFP_KERNEL); 154 if (!raw_capacity) { 155 pr_err("cpu_capacity: failed to allocate memory for raw capacities\n"); 156 cap_parsing_failed = true; 157 return false; 158 } 159 } 160 capacity_scale = max(cpu_capacity, capacity_scale); 161 raw_capacity[cpu] = cpu_capacity; 162 pr_debug("cpu_capacity: %pOF cpu_capacity=%u (raw)\n", 163 cpu_node, raw_capacity[cpu]); 164 } else { 165 if (raw_capacity) { 166 pr_err("cpu_capacity: missing %pOF raw capacity\n", 167 cpu_node); 168 pr_err("cpu_capacity: partial information: fallback to 1024 for all CPUs\n"); 169 } 170 cap_parsing_failed = true; 171 free_raw_capacity(); 172 } 173 174 return !ret; 175 } 176 177 #ifdef CONFIG_CPU_FREQ 178 static cpumask_var_t cpus_to_visit __initdata; 179 static void __init parsing_done_workfn(struct work_struct *work); 180 static __initdata DECLARE_WORK(parsing_done_work, parsing_done_workfn); 181 182 static int __init 183 init_cpu_capacity_callback(struct notifier_block *nb, 184 unsigned long val, 185 void *data) 186 { 187 struct cpufreq_policy *policy = data; 188 int cpu; 189 190 if (!raw_capacity) 191 return 0; 192 193 if (val != CPUFREQ_NOTIFY) 194 return 0; 195 196 pr_debug("cpu_capacity: init cpu capacity for CPUs [%*pbl] (to_visit=%*pbl)\n", 197 cpumask_pr_args(policy->related_cpus), 198 cpumask_pr_args(cpus_to_visit)); 199 200 cpumask_andnot(cpus_to_visit, cpus_to_visit, policy->related_cpus); 201 202 for_each_cpu(cpu, policy->related_cpus) { 203 raw_capacity[cpu] = topology_get_cpu_scale(NULL, cpu) * 204 policy->cpuinfo.max_freq / 1000UL; 205 capacity_scale = max(raw_capacity[cpu], capacity_scale); 206 } 207 208 if (cpumask_empty(cpus_to_visit)) { 209 topology_normalize_cpu_scale(); 210 free_raw_capacity(); 211 pr_debug("cpu_capacity: parsing done\n"); 212 schedule_work(&parsing_done_work); 213 } 214 215 return 0; 216 } 217 218 static struct notifier_block init_cpu_capacity_notifier __initdata = { 219 .notifier_call = init_cpu_capacity_callback, 220 }; 221 222 static int __init register_cpufreq_notifier(void) 223 { 224 int ret; 225 226 /* 227 * on ACPI-based systems we need to use the default cpu capacity 228 * until we have the necessary code to parse the cpu capacity, so 229 * skip registering cpufreq notifier. 230 */ 231 if (!acpi_disabled || !raw_capacity) 232 return -EINVAL; 233 234 if (!alloc_cpumask_var(&cpus_to_visit, GFP_KERNEL)) { 235 pr_err("cpu_capacity: failed to allocate memory for cpus_to_visit\n"); 236 return -ENOMEM; 237 } 238 239 cpumask_copy(cpus_to_visit, cpu_possible_mask); 240 241 ret = cpufreq_register_notifier(&init_cpu_capacity_notifier, 242 CPUFREQ_POLICY_NOTIFIER); 243 244 if (ret) 245 free_cpumask_var(cpus_to_visit); 246 247 return ret; 248 } 249 core_initcall(register_cpufreq_notifier); 250 251 static void __init parsing_done_workfn(struct work_struct *work) 252 { 253 cpufreq_unregister_notifier(&init_cpu_capacity_notifier, 254 CPUFREQ_POLICY_NOTIFIER); 255 free_cpumask_var(cpus_to_visit); 256 } 257 258 #else 259 core_initcall(free_raw_capacity); 260 #endif 261