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/acpi.h>
  15 #include <linux/cpu.h>
  16 #include <linux/cpumask.h>
  17 #include <linux/init.h>
  18 #include <linux/percpu.h>
  19 #include <linux/node.h>
  20 #include <linux/nodemask.h>
  21 #include <linux/of.h>
  22 #include <linux/sched.h>
  23 #include <linux/slab.h>
  24 #include <linux/string.h>
  25 #include <linux/cpufreq.h>
  26
  27 #include <asm/cpu.h>
  28 #include <asm/cputype.h>
  29 #include <asm/topology.h>
  30
  31 static DEFINE_PER_CPU(unsigned long, cpu_scale) = SCHED_CAPACITY_SCALE;
  32 static DEFINE_MUTEX(cpu_scale_mutex);
  33
  34 unsigned long arch_scale_cpu_capacity(struct sched_domain *sd, int cpu)
  35 {
  36         return per_cpu(cpu_scale, cpu);
  37 }
  38
  39 static void set_capacity_scale(unsigned int cpu, unsigned long capacity)
  40 {
  41         per_cpu(cpu_scale, cpu) = capacity;
  42 }
  43
  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
 101 static u32 capacity_scale;
 102 static u32 *raw_capacity;
 103 static bool cap_parsing_failed;
 104
 105 static void __init parse_cpu_capacity(struct device_node *cpu_node, int cpu)
 106 {
 107         int ret;
 108         u32 cpu_capacity;
 109
 110         if (cap_parsing_failed)
 111                 return;
 112
 113         ret = of_property_read_u32(cpu_node,
 114                                    "capacity-dmips-mhz",
 115                                    &cpu_capacity);
 116         if (!ret) {
 117                 if (!raw_capacity) {
 118                         raw_capacity = kcalloc(num_possible_cpus(),
 119                                                sizeof(*raw_capacity),
 120                                                GFP_KERNEL);
 121                         if (!raw_capacity) {
 122                                 pr_err("cpu_capacity: failed to allocate memory for raw capacities\n");
 123                                 cap_parsing_failed = true;
 124                                 return;
 125                         }
 126                 }
 127                 capacity_scale = max(cpu_capacity, capacity_scale);
 128                 raw_capacity[cpu] = cpu_capacity;
 129                 pr_debug("cpu_capacity: %s cpu_capacity=%u (raw)\n",
 130                         cpu_node->full_name, raw_capacity[cpu]);
 131         } else {
 132                 if (raw_capacity) {
 133                         pr_err("cpu_capacity: missing %s raw capacity\n",
 134                                 cpu_node->full_name);
 135                         pr_err("cpu_capacity: partial information: fallback to 1024 for all CPUs\n");
 136                 }
 137                 cap_parsing_failed = true;
 138                 kfree(raw_capacity);
 139         }
 140 }
 141
 142 static void normalize_cpu_capacity(void)
 143 {
 144         u64 capacity;
 145         int cpu;
 146
 147         if (!raw_capacity || cap_parsing_failed)
 148                 return;
 149
 150         pr_debug("cpu_capacity: capacity_scale=%u\n", capacity_scale);
 151         mutex_lock(&cpu_scale_mutex);
 152         for_each_possible_cpu(cpu) {
 153                 pr_debug("cpu_capacity: cpu=%d raw_capacity=%u\n",
 154                          cpu, raw_capacity[cpu]);
 155                 capacity = (raw_capacity[cpu] << SCHED_CAPACITY_SHIFT)
 156                         / capacity_scale;
 157                 set_capacity_scale(cpu, capacity);
 158                 pr_debug("cpu_capacity: CPU%d cpu_capacity=%lu\n",
 159                         cpu, arch_scale_cpu_capacity(NULL, cpu));
 160         }
 161         mutex_unlock(&cpu_scale_mutex);
 162 }
 163
 164 #ifdef CONFIG_CPU_FREQ
 165 static cpumask_var_t cpus_to_visit;
 166 static bool cap_parsing_done;
 167 static void parsing_done_workfn(struct work_struct *work);
 168 static DECLARE_WORK(parsing_done_work, parsing_done_workfn);
 169
 170 static int
 171 init_cpu_capacity_callback(struct notifier_block *nb,
 172                            unsigned long val,
 173                            void *data)
 174 {
 175         struct cpufreq_policy *policy = data;
 176         int cpu;
 177
 178         if (cap_parsing_failed || cap_parsing_done)
 179                 return 0;
 180
 181         switch (val) {
 182         case CPUFREQ_NOTIFY:
 183                 pr_debug("cpu_capacity: init cpu capacity for CPUs [%*pbl] (to_visit=%*pbl)\n",
 184                                 cpumask_pr_args(policy->related_cpus),
 185                                 cpumask_pr_args(cpus_to_visit));
 186                 cpumask_andnot(cpus_to_visit,
 187                                cpus_to_visit,
 188                                policy->related_cpus);
 189                 for_each_cpu(cpu, policy->related_cpus) {
 190                         raw_capacity[cpu] = arch_scale_cpu_capacity(NULL, cpu) *
 191                                             policy->cpuinfo.max_freq / 1000UL;
 192                         capacity_scale = max(raw_capacity[cpu], capacity_scale);
 193                 }
 194                 if (cpumask_empty(cpus_to_visit)) {
 195                         normalize_cpu_capacity();
 196                         kfree(raw_capacity);
 197                         pr_debug("cpu_capacity: parsing done\n");
 198                         cap_parsing_done = true;
 199                         schedule_work(&parsing_done_work);
 200                 }
 201         }
 202         return 0;
 203 }
 204
 205 static struct notifier_block init_cpu_capacity_notifier = {
 206         .notifier_call = init_cpu_capacity_callback,
 207 };
 208
 209 static int __init register_cpufreq_notifier(void)
 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 || cap_parsing_failed)
 217                 return -EINVAL;
 218
 219         if (!alloc_cpumask_var(&cpus_to_visit, GFP_KERNEL)) {
 220                 pr_err("cpu_capacity: failed to allocate memory for cpus_to_visit\n");
 221                 return -ENOMEM;
 222         }
 223         cpumask_copy(cpus_to_visit, cpu_possible_mask);
 224
 225         return cpufreq_register_notifier(&init_cpu_capacity_notifier,
 226                                          CPUFREQ_POLICY_NOTIFIER);
 227 }
 228 core_initcall(register_cpufreq_notifier);
 229
 230 static void parsing_done_workfn(struct work_struct *work)
 231 {
 232         cpufreq_unregister_notifier(&init_cpu_capacity_notifier,
 233                                          CPUFREQ_POLICY_NOTIFIER);
 234 }
 235
 236 #else
 237 static int __init free_raw_capacity(void)
 238 {
 239         kfree(raw_capacity);
 240
 241         return 0;
 242 }
 243 core_initcall(free_raw_capacity);
 244 #endif
 245
 246 static int __init get_cpu_for_node(struct device_node *node)
 247 {
 248         struct device_node *cpu_node;
 249         int cpu;
 250
 251         cpu_node = of_parse_phandle(node, "cpu", 0);
 252         if (!cpu_node)
 253                 return -1;
 254
 255         for_each_possible_cpu(cpu) {
 256                 if (of_get_cpu_node(cpu, NULL) == cpu_node) {
 257                         parse_cpu_capacity(cpu_node, cpu);
 258                         of_node_put(cpu_node);
 259                         return cpu;
 260                 }
 261         }
 262
 263         pr_crit("Unable to find CPU node for %s\n", cpu_node->full_name);
 264
 265         of_node_put(cpu_node);
 266         return -1;
 267 }
 268
 269 static int __init parse_core(struct device_node *core, int cluster_id,
 270                              int core_id)
 271 {
 272         char name[10];
 273         bool leaf = true;
 274         int i = 0;
 275         int cpu;
 276         struct device_node *t;
 277
 278         do {
 279                 snprintf(name, sizeof(name), "thread%d", i);
 280                 t = of_get_child_by_name(core, name);
 281                 if (t) {
 282                         leaf = false;
 283                         cpu = get_cpu_for_node(t);
 284                         if (cpu >= 0) {
 285                                 cpu_topology[cpu].cluster_id = cluster_id;
 286                                 cpu_topology[cpu].core_id = core_id;
 287                                 cpu_topology[cpu].thread_id = i;
 288                         } else {
 289                                 pr_err("%s: Can't get CPU for thread\n",
 290                                        t->full_name);
 291                                 of_node_put(t);
 292                                 return -EINVAL;
 293                         }
 294                         of_node_put(t);
 295                 }
 296                 i++;
 297         } while (t);
 298
 299         cpu = get_cpu_for_node(core);
 300         if (cpu >= 0) {
 301                 if (!leaf) {
 302                         pr_err("%s: Core has both threads and CPU\n",
 303                                core->full_name);
 304                         return -EINVAL;
 305                 }
 306
 307                 cpu_topology[cpu].cluster_id = cluster_id;
 308                 cpu_topology[cpu].core_id = core_id;
 309         } else if (leaf) {
 310                 pr_err("%s: Can't get CPU for leaf core\n", core->full_name);
 311                 return -EINVAL;
 312         }
 313
 314         return 0;
 315 }
 316
 317 static int __init parse_cluster(struct device_node *cluster, int depth)
 318 {
 319         char name[10];
 320         bool leaf = true;
 321         bool has_cores = false;
 322         struct device_node *c;
 323         static int cluster_id __initdata;
 324         int core_id = 0;
 325         int i, ret;
 326
 327         /*
 328          * First check for child clusters; we currently ignore any
 329          * information about the nesting of clusters and present the
 330          * scheduler with a flat list of them.
 331          */
 332         i = 0;
 333         do {
 334                 snprintf(name, sizeof(name), "cluster%d", i);
 335                 c = of_get_child_by_name(cluster, name);
 336                 if (c) {
 337                         leaf = false;
 338                         ret = parse_cluster(c, depth + 1);
 339                         of_node_put(c);
 340                         if (ret != 0)
 341                                 return ret;
 342                 }
 343                 i++;
 344         } while (c);
 345
 346         /* Now check for cores */
 347         i = 0;
 348         do {
 349                 snprintf(name, sizeof(name), "core%d", i);
 350                 c = of_get_child_by_name(cluster, name);
 351                 if (c) {
 352                         has_cores = true;
 353
 354                         if (depth == 0) {
 355                                 pr_err("%s: cpu-map children should be clusters\n",
 356                                        c->full_name);
 357                                 of_node_put(c);
 358                                 return -EINVAL;
 359                         }
 360
 361                         if (leaf) {
 362                                 ret = parse_core(c, cluster_id, core_id++);
 363                         } else {
 364                                 pr_err("%s: Non-leaf cluster with core %s\n",
 365                                        cluster->full_name, name);
 366                                 ret = -EINVAL;
 367                         }
 368
 369                         of_node_put(c);
 370                         if (ret != 0)
 371                                 return ret;
 372                 }
 373                 i++;
 374         } while (c);
 375
 376         if (leaf && !has_cores)
 377                 pr_warn("%s: empty cluster\n", cluster->full_name);
 378
 379         if (leaf)
 380                 cluster_id++;
 381
 382         return 0;
 383 }
 384
 385 static int __init parse_dt_topology(void)
 386 {
 387         struct device_node *cn, *map;
 388         int ret = 0;
 389         int cpu;
 390
 391         cn = of_find_node_by_path("/cpus");
 392         if (!cn) {
 393                 pr_err("No CPU information found in DT\n");
 394                 return 0;
 395         }
 396
 397         /*
 398          * When topology is provided cpu-map is essentially a root
 399          * cluster with restricted subnodes.
 400          */
 401         map = of_get_child_by_name(cn, "cpu-map");
 402         if (!map) {
 403                 cap_parsing_failed = true;
 404                 goto out;
 405         }
 406
 407         ret = parse_cluster(map, 0);
 408         if (ret != 0)
 409                 goto out_map;
 410
 411         normalize_cpu_capacity();
 412
 413         /*
 414          * Check that all cores are in the topology; the SMP code will
 415          * only mark cores described in the DT as possible.
 416          */
 417         for_each_possible_cpu(cpu)
 418                 if (cpu_topology[cpu].cluster_id == -1)
 419                         ret = -EINVAL;
 420
 421 out_map:
 422         of_node_put(map);
 423 out:
 424         of_node_put(cn);
 425         return ret;
 426 }
 427
 428 /*
 429  * cpu topology table
 430  */
 431 struct cpu_topology cpu_topology[NR_CPUS];
 432 EXPORT_SYMBOL_GPL(cpu_topology);
 433
 434 const struct cpumask *cpu_coregroup_mask(int cpu)
 435 {
 436         return &cpu_topology[cpu].core_sibling;
 437 }
 438
 439 static void update_siblings_masks(unsigned int cpuid)
 440 {
 441         struct cpu_topology *cpu_topo, *cpuid_topo = &cpu_topology[cpuid];
 442         int cpu;
 443
 444         /* update core and thread sibling masks */
 445         for_each_possible_cpu(cpu) {
 446                 cpu_topo = &cpu_topology[cpu];
 447
 448                 if (cpuid_topo->cluster_id != cpu_topo->cluster_id)
 449                         continue;
 450
 451                 cpumask_set_cpu(cpuid, &cpu_topo->core_sibling);
 452                 if (cpu != cpuid)
 453                         cpumask_set_cpu(cpu, &cpuid_topo->core_sibling);
 454
 455                 if (cpuid_topo->core_id != cpu_topo->core_id)
 456                         continue;
 457
 458                 cpumask_set_cpu(cpuid, &cpu_topo->thread_sibling);
 459                 if (cpu != cpuid)
 460                         cpumask_set_cpu(cpu, &cpuid_topo->thread_sibling);
 461         }
 462 }
 463
 464 void store_cpu_topology(unsigned int cpuid)
 465 {
 466         struct cpu_topology *cpuid_topo = &cpu_topology[cpuid];
 467         u64 mpidr;
 468
 469         if (cpuid_topo->cluster_id != -1)
 470                 goto topology_populated;
 471
 472         mpidr = read_cpuid_mpidr();
 473
 474         /* Uniprocessor systems can rely on default topology values */
 475         if (mpidr & MPIDR_UP_BITMASK)
 476                 return;
 477
 478         /* Create cpu topology mapping based on MPIDR. */
 479         if (mpidr & MPIDR_MT_BITMASK) {
 480                 /* Multiprocessor system : Multi-threads per core */
 481                 cpuid_topo->thread_id  = MPIDR_AFFINITY_LEVEL(mpidr, 0);
 482                 cpuid_topo->core_id    = MPIDR_AFFINITY_LEVEL(mpidr, 1);
 483                 cpuid_topo->cluster_id = MPIDR_AFFINITY_LEVEL(mpidr, 2) |
 484                                          MPIDR_AFFINITY_LEVEL(mpidr, 3) << 8;
 485         } else {
 486                 /* Multiprocessor system : Single-thread per core */
 487                 cpuid_topo->thread_id  = -1;
 488                 cpuid_topo->core_id    = MPIDR_AFFINITY_LEVEL(mpidr, 0);
 489                 cpuid_topo->cluster_id = MPIDR_AFFINITY_LEVEL(mpidr, 1) |
 490                                          MPIDR_AFFINITY_LEVEL(mpidr, 2) << 8 |
 491                                          MPIDR_AFFINITY_LEVEL(mpidr, 3) << 16;
 492         }
 493
 494         pr_debug("CPU%u: cluster %d core %d thread %d mpidr %#016llx\n",
 495                  cpuid, cpuid_topo->cluster_id, cpuid_topo->core_id,
 496                  cpuid_topo->thread_id, mpidr);
 497
 498 topology_populated:
 499         update_siblings_masks(cpuid);
 500 }
 501
 502 static void __init reset_cpu_topology(void)
 503 {
 504         unsigned int cpu;
 505
 506         for_each_possible_cpu(cpu) {
 507                 struct cpu_topology *cpu_topo = &cpu_topology[cpu];
 508
 509                 cpu_topo->thread_id = -1;
 510                 cpu_topo->core_id = 0;
 511                 cpu_topo->cluster_id = -1;
 512
 513                 cpumask_clear(&cpu_topo->core_sibling);
 514                 cpumask_set_cpu(cpu, &cpu_topo->core_sibling);
 515                 cpumask_clear(&cpu_topo->thread_sibling);
 516                 cpumask_set_cpu(cpu, &cpu_topo->thread_sibling);
 517         }
 518 }
 519
 520 void __init init_cpu_topology(void)
 521 {
 522         reset_cpu_topology();
 523
 524         /*
 525          * Discard anything that was parsed if we hit an error so we
 526          * don't use partial information.
 527          */
 528         if (of_have_populated_dt() && parse_dt_topology())
 529                 reset_cpu_topology();
 530 }