1 /* 2 * arch/arm64/kernel/topology.c 3 * 4 * Copyright (C) 2011,2013,2014 Linaro Limited. 5 * 6 * Based on the arm32 version written by Vincent Guittot in turn based on 7 * arch/sh/kernel/topology.c 8 * 9 * This file is subject to the terms and conditions of the GNU General Public 10 * License. See the file "COPYING" in the main directory of this archive 11 * for more details. 12 */ 13 14 #include <linux/cpu.h> 15 #include <linux/cpumask.h> 16 #include <linux/init.h> 17 #include <linux/percpu.h> 18 #include <linux/node.h> 19 #include <linux/nodemask.h> 20 #include <linux/of.h> 21 #include <linux/sched.h> 22 23 #include <asm/cputype.h> 24 #include <asm/topology.h> 25 26 static int __init get_cpu_for_node(struct device_node *node) 27 { 28 struct device_node *cpu_node; 29 int cpu; 30 31 cpu_node = of_parse_phandle(node, "cpu", 0); 32 if (!cpu_node) 33 return -1; 34 35 for_each_possible_cpu(cpu) { 36 if (of_get_cpu_node(cpu, NULL) == cpu_node) { 37 of_node_put(cpu_node); 38 return cpu; 39 } 40 } 41 42 pr_crit("Unable to find CPU node for %s\n", cpu_node->full_name); 43 44 of_node_put(cpu_node); 45 return -1; 46 } 47 48 static int __init parse_core(struct device_node *core, int cluster_id, 49 int core_id) 50 { 51 char name[10]; 52 bool leaf = true; 53 int i = 0; 54 int cpu; 55 struct device_node *t; 56 57 do { 58 snprintf(name, sizeof(name), "thread%d", i); 59 t = of_get_child_by_name(core, name); 60 if (t) { 61 leaf = false; 62 cpu = get_cpu_for_node(t); 63 if (cpu >= 0) { 64 cpu_topology[cpu].cluster_id = cluster_id; 65 cpu_topology[cpu].core_id = core_id; 66 cpu_topology[cpu].thread_id = i; 67 } else { 68 pr_err("%s: Can't get CPU for thread\n", 69 t->full_name); 70 of_node_put(t); 71 return -EINVAL; 72 } 73 of_node_put(t); 74 } 75 i++; 76 } while (t); 77 78 cpu = get_cpu_for_node(core); 79 if (cpu >= 0) { 80 if (!leaf) { 81 pr_err("%s: Core has both threads and CPU\n", 82 core->full_name); 83 return -EINVAL; 84 } 85 86 cpu_topology[cpu].cluster_id = cluster_id; 87 cpu_topology[cpu].core_id = core_id; 88 } else if (leaf) { 89 pr_err("%s: Can't get CPU for leaf core\n", core->full_name); 90 return -EINVAL; 91 } 92 93 return 0; 94 } 95 96 static int __init parse_cluster(struct device_node *cluster, int depth) 97 { 98 char name[10]; 99 bool leaf = true; 100 bool has_cores = false; 101 struct device_node *c; 102 static int cluster_id __initdata; 103 int core_id = 0; 104 int i, ret; 105 106 /* 107 * First check for child clusters; we currently ignore any 108 * information about the nesting of clusters and present the 109 * scheduler with a flat list of them. 110 */ 111 i = 0; 112 do { 113 snprintf(name, sizeof(name), "cluster%d", i); 114 c = of_get_child_by_name(cluster, name); 115 if (c) { 116 leaf = false; 117 ret = parse_cluster(c, depth + 1); 118 of_node_put(c); 119 if (ret != 0) 120 return ret; 121 } 122 i++; 123 } while (c); 124 125 /* Now check for cores */ 126 i = 0; 127 do { 128 snprintf(name, sizeof(name), "core%d", i); 129 c = of_get_child_by_name(cluster, name); 130 if (c) { 131 has_cores = true; 132 133 if (depth == 0) { 134 pr_err("%s: cpu-map children should be clusters\n", 135 c->full_name); 136 of_node_put(c); 137 return -EINVAL; 138 } 139 140 if (leaf) { 141 ret = parse_core(c, cluster_id, core_id++); 142 } else { 143 pr_err("%s: Non-leaf cluster with core %s\n", 144 cluster->full_name, name); 145 ret = -EINVAL; 146 } 147 148 of_node_put(c); 149 if (ret != 0) 150 return ret; 151 } 152 i++; 153 } while (c); 154 155 if (leaf && !has_cores) 156 pr_warn("%s: empty cluster\n", cluster->full_name); 157 158 if (leaf) 159 cluster_id++; 160 161 return 0; 162 } 163 164 static int __init parse_dt_topology(void) 165 { 166 struct device_node *cn, *map; 167 int ret = 0; 168 int cpu; 169 170 cn = of_find_node_by_path("/cpus"); 171 if (!cn) { 172 pr_err("No CPU information found in DT\n"); 173 return 0; 174 } 175 176 /* 177 * When topology is provided cpu-map is essentially a root 178 * cluster with restricted subnodes. 179 */ 180 map = of_get_child_by_name(cn, "cpu-map"); 181 if (!map) 182 goto out; 183 184 ret = parse_cluster(map, 0); 185 if (ret != 0) 186 goto out_map; 187 188 /* 189 * Check that all cores are in the topology; the SMP code will 190 * only mark cores described in the DT as possible. 191 */ 192 for_each_possible_cpu(cpu) 193 if (cpu_topology[cpu].cluster_id == -1) 194 ret = -EINVAL; 195 196 out_map: 197 of_node_put(map); 198 out: 199 of_node_put(cn); 200 return ret; 201 } 202 203 /* 204 * cpu topology table 205 */ 206 struct cpu_topology cpu_topology[NR_CPUS]; 207 EXPORT_SYMBOL_GPL(cpu_topology); 208 209 const struct cpumask *cpu_coregroup_mask(int cpu) 210 { 211 return &cpu_topology[cpu].core_sibling; 212 } 213 214 static void update_siblings_masks(unsigned int cpuid) 215 { 216 struct cpu_topology *cpu_topo, *cpuid_topo = &cpu_topology[cpuid]; 217 int cpu; 218 219 /* update core and thread sibling masks */ 220 for_each_possible_cpu(cpu) { 221 cpu_topo = &cpu_topology[cpu]; 222 223 if (cpuid_topo->cluster_id != cpu_topo->cluster_id) 224 continue; 225 226 cpumask_set_cpu(cpuid, &cpu_topo->core_sibling); 227 if (cpu != cpuid) 228 cpumask_set_cpu(cpu, &cpuid_topo->core_sibling); 229 230 if (cpuid_topo->core_id != cpu_topo->core_id) 231 continue; 232 233 cpumask_set_cpu(cpuid, &cpu_topo->thread_sibling); 234 if (cpu != cpuid) 235 cpumask_set_cpu(cpu, &cpuid_topo->thread_sibling); 236 } 237 } 238 239 void store_cpu_topology(unsigned int cpuid) 240 { 241 struct cpu_topology *cpuid_topo = &cpu_topology[cpuid]; 242 u64 mpidr; 243 244 if (cpuid_topo->cluster_id != -1) 245 goto topology_populated; 246 247 mpidr = read_cpuid_mpidr(); 248 249 /* Uniprocessor systems can rely on default topology values */ 250 if (mpidr & MPIDR_UP_BITMASK) 251 return; 252 253 /* Create cpu topology mapping based on MPIDR. */ 254 if (mpidr & MPIDR_MT_BITMASK) { 255 /* Multiprocessor system : Multi-threads per core */ 256 cpuid_topo->thread_id = MPIDR_AFFINITY_LEVEL(mpidr, 0); 257 cpuid_topo->core_id = MPIDR_AFFINITY_LEVEL(mpidr, 1); 258 cpuid_topo->cluster_id = MPIDR_AFFINITY_LEVEL(mpidr, 2) | 259 MPIDR_AFFINITY_LEVEL(mpidr, 3) << 8; 260 } else { 261 /* Multiprocessor system : Single-thread per core */ 262 cpuid_topo->thread_id = -1; 263 cpuid_topo->core_id = MPIDR_AFFINITY_LEVEL(mpidr, 0); 264 cpuid_topo->cluster_id = MPIDR_AFFINITY_LEVEL(mpidr, 1) | 265 MPIDR_AFFINITY_LEVEL(mpidr, 2) << 8 | 266 MPIDR_AFFINITY_LEVEL(mpidr, 3) << 16; 267 } 268 269 pr_debug("CPU%u: cluster %d core %d thread %d mpidr %#016llx\n", 270 cpuid, cpuid_topo->cluster_id, cpuid_topo->core_id, 271 cpuid_topo->thread_id, mpidr); 272 273 topology_populated: 274 update_siblings_masks(cpuid); 275 } 276 277 static void __init reset_cpu_topology(void) 278 { 279 unsigned int cpu; 280 281 for_each_possible_cpu(cpu) { 282 struct cpu_topology *cpu_topo = &cpu_topology[cpu]; 283 284 cpu_topo->thread_id = -1; 285 cpu_topo->core_id = 0; 286 cpu_topo->cluster_id = -1; 287 288 cpumask_clear(&cpu_topo->core_sibling); 289 cpumask_set_cpu(cpu, &cpu_topo->core_sibling); 290 cpumask_clear(&cpu_topo->thread_sibling); 291 cpumask_set_cpu(cpu, &cpu_topo->thread_sibling); 292 } 293 } 294 295 void __init init_cpu_topology(void) 296 { 297 reset_cpu_topology(); 298 299 /* 300 * Discard anything that was parsed if we hit an error so we 301 * don't use partial information. 302 */ 303 if (parse_dt_topology()) 304 reset_cpu_topology(); 305 } 306