arch/arm64/kernel/topology.c

   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 #include <linux/slab.h>
  23 #include <linux/string.h>
  24 #include <linux/cpufreq.h>
  25
  26 #include <asm/cpu.h>
  27 #include <asm/cputype.h>
  28 #include <asm/topology.h>
  29
  30 static DEFINE_PER_CPU(unsigned long, cpu_scale) = SCHED_CAPACITY_SCALE;
  31 static DEFINE_MUTEX(cpu_scale_mutex);
  32
  33 unsigned long arch_scale_cpu_capacity(struct sched_domain *sd, int cpu)
  34 {
  35         return per_cpu(cpu_scale, cpu);
  36 }
  37
  38 static void set_capacity_scale(unsigned int cpu, unsigned long capacity)
  39 {
  40         per_cpu(cpu_scale, cpu) = capacity;
  41 }
  42
  43 #ifdef CONFIG_PROC_SYSCTL
  44 static ssize_t cpu_capacity_show(struct device *dev,
  45                                  struct device_attribute *attr,
  46                                  char *buf)
  47 {
  48         struct cpu *cpu = container_of(dev, struct cpu, dev);
  49
  50         return sprintf(buf, "%lu\n",
  51                         arch_scale_cpu_capacity(NULL, cpu->dev.id));
  52 }
  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, i;
  61         unsigned long new_capacity;
  62         ssize_t ret;
  63
  64         if (count) {
  65                 ret = kstrtoul(buf, 0, &new_capacity);
  66                 if (ret)
  67                         return ret;
  68                 if (new_capacity > SCHED_CAPACITY_SCALE)
  69                         return -EINVAL;
  70
  71                 mutex_lock(&cpu_scale_mutex);
  72                 for_each_cpu(i, &cpu_topology[this_cpu].core_sibling)
  73                         set_capacity_scale(i, new_capacity);
  74                 mutex_unlock(&cpu_scale_mutex);
  75         }
  76
  77         return count;
  78 }
  79
  80 static DEVICE_ATTR_RW(cpu_capacity);
  81
  82 static int register_cpu_capacity_sysctl(void)
  83 {
  84         int i;
  85         struct device *cpu;
  86
  87         for_each_possible_cpu(i) {
  88                 cpu = get_cpu_device(i);
  89                 if (!cpu) {
  90                         pr_err("%s: too early to get CPU%d device!\n",
  91                                __func__, i);
  92                         continue;
  93                 }
  94                 device_create_file(cpu, &dev_attr_cpu_capacity);
  95         }
  96
  97         return 0;
  98 }
  99 subsys_initcall(register_cpu_capacity_sysctl);
 100 #endif
 101
 102 static u32 capacity_scale;
 103 static u32 *raw_capacity;
 104 static bool cap_parsing_failed;
 105
 106 static void __init parse_cpu_capacity(struct device_node *cpu_node, int cpu)
 107 {
 108         int ret;
 109         u32 cpu_capacity;
 110
 111         if (cap_parsing_failed)
 112                 return;
 113
 114         ret = of_property_read_u32(cpu_node,
 115                                    "capacity-dmips-mhz",
 116                                    &cpu_capacity);
 117         if (!ret) {
 118                 if (!raw_capacity) {
 119                         raw_capacity = kcalloc(num_possible_cpus(),
 120                                                sizeof(*raw_capacity),
 121                                                GFP_KERNEL);
 122                         if (!raw_capacity) {
 123                                 pr_err("cpu_capacity: failed to allocate memory for raw capacities\n");
 124                                 cap_parsing_failed = true;
 125                                 return;
 126                         }
 127                 }
 128                 capacity_scale = max(cpu_capacity, capacity_scale);
 129                 raw_capacity[cpu] = cpu_capacity;
 130                 pr_debug("cpu_capacity: %s cpu_capacity=%u (raw)\n",
 131                         cpu_node->full_name, raw_capacity[cpu]);
 132         } else {
 133                 if (raw_capacity) {
 134                         pr_err("cpu_capacity: missing %s raw capacity\n",
 135                                 cpu_node->full_name);
 136                         pr_err("cpu_capacity: partial information: fallback to 1024 for all CPUs\n");
 137                 }
 138                 cap_parsing_failed = true;
 139                 kfree(raw_capacity);
 140         }
 141 }
 142
 143 static void normalize_cpu_capacity(void)
 144 {
 145         u64 capacity;
 146         int cpu;
 147
 148         if (!raw_capacity || cap_parsing_failed)
 149                 return;
 150
 151         pr_debug("cpu_capacity: capacity_scale=%u\n", capacity_scale);
 152         mutex_lock(&cpu_scale_mutex);
 153         for_each_possible_cpu(cpu) {
 154                 pr_debug("cpu_capacity: cpu=%d raw_capacity=%u\n",
 155                          cpu, raw_capacity[cpu]);
 156                 capacity = (raw_capacity[cpu] << SCHED_CAPACITY_SHIFT)
 157                         / capacity_scale;
 158                 set_capacity_scale(cpu, capacity);
 159                 pr_debug("cpu_capacity: CPU%d cpu_capacity=%lu\n",
 160                         cpu, arch_scale_cpu_capacity(NULL, cpu));
 161         }
 162         mutex_unlock(&cpu_scale_mutex);
 163 }
 164
 165 #ifdef CONFIG_CPU_FREQ
 166 static cpumask_var_t cpus_to_visit;
 167 static bool cap_parsing_done;
 168 static void parsing_done_workfn(struct work_struct *work);
 169 static DECLARE_WORK(parsing_done_work, parsing_done_workfn);
 170
 171 static int
 172 init_cpu_capacity_callback(struct notifier_block *nb,
 173                            unsigned long val,
 174                            void *data)
 175 {
 176         struct cpufreq_policy *policy = data;
 177         int cpu;
 178
 179         if (cap_parsing_failed || cap_parsing_done)
 180                 return 0;
 181
 182         switch (val) {
 183         case CPUFREQ_NOTIFY:
 184                 pr_debug("cpu_capacity: init cpu capacity for CPUs [%*pbl] (to_visit=%*pbl)\n",
 185                                 cpumask_pr_args(policy->related_cpus),
 186                                 cpumask_pr_args(cpus_to_visit));
 187                 cpumask_andnot(cpus_to_visit,
 188                                cpus_to_visit,
 189                                policy->related_cpus);
 190                 for_each_cpu(cpu, policy->related_cpus) {
 191                         raw_capacity[cpu] = arch_scale_cpu_capacity(NULL, cpu) *
 192                                             policy->cpuinfo.max_freq / 1000UL;
 193                         capacity_scale = max(raw_capacity[cpu], capacity_scale);
 194                 }
 195                 if (cpumask_empty(cpus_to_visit)) {
 196                         normalize_cpu_capacity();
 197                         kfree(raw_capacity);
 198                         pr_debug("cpu_capacity: parsing done\n");
 199                         cap_parsing_done = true;
 200                         schedule_work(&parsing_done_work);
 201                 }
 202         }
 203         return 0;
 204 }
 205
 206 static struct notifier_block init_cpu_capacity_notifier = {
 207         .notifier_call = init_cpu_capacity_callback,
 208 };
 209
 210 static int __init register_cpufreq_notifier(void)
 211 {
 212         if (cap_parsing_failed)
 213                 return -EINVAL;
 214
 215         if (!alloc_cpumask_var(&cpus_to_visit, GFP_KERNEL)) {
 216                 pr_err("cpu_capacity: failed to allocate memory for cpus_to_visit\n");
 217                 return -ENOMEM;
 218         }
 219         cpumask_copy(cpus_to_visit, cpu_possible_mask);
 220
 221         return cpufreq_register_notifier(&init_cpu_capacity_notifier,
 222                                          CPUFREQ_POLICY_NOTIFIER);
 223 }
 224 core_initcall(register_cpufreq_notifier);
 225
 226 static void parsing_done_workfn(struct work_struct *work)
 227 {
 228         cpufreq_unregister_notifier(&init_cpu_capacity_notifier,
 229                                          CPUFREQ_POLICY_NOTIFIER);
 230 }
 231
 232 #else
 233 static int __init free_raw_capacity(void)
 234 {
 235         kfree(raw_capacity);
 236
 237         return 0;
 238 }
 239 core_initcall(free_raw_capacity);
 240 #endif
 241
 242 static int __init get_cpu_for_node(struct device_node *node)
 243 {
 244         struct device_node *cpu_node;
 245         int cpu;
 246
 247         cpu_node = of_parse_phandle(node, "cpu", 0);
 248         if (!cpu_node)
 249                 return -1;
 250
 251         for_each_possible_cpu(cpu) {
 252                 if (of_get_cpu_node(cpu, NULL) == cpu_node) {
 253                         parse_cpu_capacity(cpu_node, cpu);
 254                         of_node_put(cpu_node);
 255                         return cpu;
 256                 }
 257         }
 258
 259         pr_crit("Unable to find CPU node for %s\n", cpu_node->full_name);
 260
 261         of_node_put(cpu_node);
 262         return -1;
 263 }
 264
 265 static int __init parse_core(struct device_node *core, int cluster_id,
 266                              int core_id)
 267 {
 268         char name[10];
 269         bool leaf = true;
 270         int i = 0;
 271         int cpu;
 272         struct device_node *t;
 273
 274         do {
 275                 snprintf(name, sizeof(name), "thread%d", i);
 276                 t = of_get_child_by_name(core, name);
 277                 if (t) {
 278                         leaf = false;
 279                         cpu = get_cpu_for_node(t);
 280                         if (cpu >= 0) {
 281                                 cpu_topology[cpu].cluster_id = cluster_id;
 282                                 cpu_topology[cpu].core_id = core_id;
 283                                 cpu_topology[cpu].thread_id = i;
 284                         } else {
 285                                 pr_err("%s: Can't get CPU for thread\n",
 286                                        t->full_name);
 287                                 of_node_put(t);
 288                                 return -EINVAL;
 289                         }
 290                         of_node_put(t);
 291                 }
 292                 i++;
 293         } while (t);
 294
 295         cpu = get_cpu_for_node(core);
 296         if (cpu >= 0) {
 297                 if (!leaf) {
 298                         pr_err("%s: Core has both threads and CPU\n",
 299                                core->full_name);
 300                         return -EINVAL;
 301                 }
 302
 303                 cpu_topology[cpu].cluster_id = cluster_id;
 304                 cpu_topology[cpu].core_id = core_id;
 305         } else if (leaf) {
 306                 pr_err("%s: Can't get CPU for leaf core\n", core->full_name);
 307                 return -EINVAL;
 308         }
 309
 310         return 0;
 311 }
 312
 313 static int __init parse_cluster(struct device_node *cluster, int depth)
 314 {
 315         char name[10];
 316         bool leaf = true;
 317         bool has_cores = false;
 318         struct device_node *c;
 319         static int cluster_id __initdata;
 320         int core_id = 0;
 321         int i, ret;
 322
 323         /*
 324          * First check for child clusters; we currently ignore any
 325          * information about the nesting of clusters and present the
 326          * scheduler with a flat list of them.
 327          */
 328         i = 0;
 329         do {
 330                 snprintf(name, sizeof(name), "cluster%d", i);
 331                 c = of_get_child_by_name(cluster, name);
 332                 if (c) {
 333                         leaf = false;
 334                         ret = parse_cluster(c, depth + 1);
 335                         of_node_put(c);
 336                         if (ret != 0)
 337                                 return ret;
 338                 }
 339                 i++;
 340         } while (c);
 341
 342         /* Now check for cores */
 343         i = 0;
 344         do {
 345                 snprintf(name, sizeof(name), "core%d", i);
 346                 c = of_get_child_by_name(cluster, name);
 347                 if (c) {
 348                         has_cores = true;
 349
 350                         if (depth == 0) {
 351                                 pr_err("%s: cpu-map children should be clusters\n",
 352                                        c->full_name);
 353                                 of_node_put(c);
 354                                 return -EINVAL;
 355                         }
 356
 357                         if (leaf) {
 358                                 ret = parse_core(c, cluster_id, core_id++);
 359                         } else {
 360                                 pr_err("%s: Non-leaf cluster with core %s\n",
 361                                        cluster->full_name, name);
 362                                 ret = -EINVAL;
 363                         }
 364
 365                         of_node_put(c);
 366                         if (ret != 0)
 367                                 return ret;
 368                 }
 369                 i++;
 370         } while (c);
 371
 372         if (leaf && !has_cores)
 373                 pr_warn("%s: empty cluster\n", cluster->full_name);
 374
 375         if (leaf)
 376                 cluster_id++;
 377
 378         return 0;
 379 }
 380
 381 static int __init parse_dt_topology(void)
 382 {
 383         struct device_node *cn, *map;
 384         int ret = 0;
 385         int cpu;
 386
 387         cn = of_find_node_by_path("/cpus");
 388         if (!cn) {
 389                 pr_err("No CPU information found in DT\n");
 390                 return 0;
 391         }
 392
 393         /*
 394          * When topology is provided cpu-map is essentially a root
 395          * cluster with restricted subnodes.
 396          */
 397         map = of_get_child_by_name(cn, "cpu-map");
 398         if (!map) {
 399                 cap_parsing_failed = true;
 400                 goto out;
 401         }
 402
 403         ret = parse_cluster(map, 0);
 404         if (ret != 0)
 405                 goto out_map;
 406
 407         normalize_cpu_capacity();
 408
 409         /*
 410          * Check that all cores are in the topology; the SMP code will
 411          * only mark cores described in the DT as possible.
 412          */
 413         for_each_possible_cpu(cpu)
 414                 if (cpu_topology[cpu].cluster_id == -1)
 415                         ret = -EINVAL;
 416
 417 out_map:
 418         of_node_put(map);
 419 out:
 420         of_node_put(cn);
 421         return ret;
 422 }
 423
 424 /*
 425  * cpu topology table
 426  */
 427 struct cpu_topology cpu_topology[NR_CPUS];
 428 EXPORT_SYMBOL_GPL(cpu_topology);
 429
 430 const struct cpumask *cpu_coregroup_mask(int cpu)
 431 {
 432         return &cpu_topology[cpu].core_sibling;
 433 }
 434
 435 static void update_siblings_masks(unsigned int cpuid)
 436 {
 437         struct cpu_topology *cpu_topo, *cpuid_topo = &cpu_topology[cpuid];
 438         int cpu;
 439
 440         /* update core and thread sibling masks */
 441         for_each_possible_cpu(cpu) {
 442                 cpu_topo = &cpu_topology[cpu];
 443
 444                 if (cpuid_topo->cluster_id != cpu_topo->cluster_id)
 445                         continue;
 446
 447                 cpumask_set_cpu(cpuid, &cpu_topo->core_sibling);
 448                 if (cpu != cpuid)
 449                         cpumask_set_cpu(cpu, &cpuid_topo->core_sibling);
 450
 451                 if (cpuid_topo->core_id != cpu_topo->core_id)
 452                         continue;
 453
 454                 cpumask_set_cpu(cpuid, &cpu_topo->thread_sibling);
 455                 if (cpu != cpuid)
 456                         cpumask_set_cpu(cpu, &cpuid_topo->thread_sibling);
 457         }
 458 }
 459
 460 void store_cpu_topology(unsigned int cpuid)
 461 {
 462         struct cpu_topology *cpuid_topo = &cpu_topology[cpuid];
 463         u64 mpidr;
 464
 465         if (cpuid_topo->cluster_id != -1)
 466                 goto topology_populated;
 467
 468         mpidr = read_cpuid_mpidr();
 469
 470         /* Uniprocessor systems can rely on default topology values */
 471         if (mpidr & MPIDR_UP_BITMASK)
 472                 return;
 473
 474         /* Create cpu topology mapping based on MPIDR. */
 475         if (mpidr & MPIDR_MT_BITMASK) {
 476                 /* Multiprocessor system : Multi-threads per core */
 477                 cpuid_topo->thread_id  = MPIDR_AFFINITY_LEVEL(mpidr, 0);
 478                 cpuid_topo->core_id    = MPIDR_AFFINITY_LEVEL(mpidr, 1);
 479                 cpuid_topo->cluster_id = MPIDR_AFFINITY_LEVEL(mpidr, 2) |
 480                                          MPIDR_AFFINITY_LEVEL(mpidr, 3) << 8;
 481         } else {
 482                 /* Multiprocessor system : Single-thread per core */
 483                 cpuid_topo->thread_id  = -1;
 484                 cpuid_topo->core_id    = MPIDR_AFFINITY_LEVEL(mpidr, 0);
 485                 cpuid_topo->cluster_id = MPIDR_AFFINITY_LEVEL(mpidr, 1) |
 486                                          MPIDR_AFFINITY_LEVEL(mpidr, 2) << 8 |
 487                                          MPIDR_AFFINITY_LEVEL(mpidr, 3) << 16;
 488         }
 489
 490         pr_debug("CPU%u: cluster %d core %d thread %d mpidr %#016llx\n",
 491                  cpuid, cpuid_topo->cluster_id, cpuid_topo->core_id,
 492                  cpuid_topo->thread_id, mpidr);
 493
 494 topology_populated:
 495         update_siblings_masks(cpuid);
 496 }
 497
 498 static void __init reset_cpu_topology(void)
 499 {
 500         unsigned int cpu;
 501
 502         for_each_possible_cpu(cpu) {
 503                 struct cpu_topology *cpu_topo = &cpu_topology[cpu];
 504
 505                 cpu_topo->thread_id = -1;
 506                 cpu_topo->core_id = 0;
 507                 cpu_topo->cluster_id = -1;
 508
 509                 cpumask_clear(&cpu_topo->core_sibling);
 510                 cpumask_set_cpu(cpu, &cpu_topo->core_sibling);
 511                 cpumask_clear(&cpu_topo->thread_sibling);
 512                 cpumask_set_cpu(cpu, &cpu_topo->thread_sibling);
 513         }
 514 }
 515
 516 void __init init_cpu_topology(void)
 517 {
 518         reset_cpu_topology();
 519
 520         /*
 521          * Discard anything that was parsed if we hit an error so we
 522          * don't use partial information.
 523          */
 524         if (of_have_populated_dt() && parse_dt_topology())
 525                 reset_cpu_topology();
 526 }