drivers/cpufreq/arm_big_little.c

   1 /*
   2  * ARM big.LITTLE Platforms CPUFreq support
   3  *
   4  * Copyright (C) 2013 ARM Ltd.
   5  * Sudeep KarkadaNagesha <sudeep.karkadanagesha@arm.com>
   6  *
   7  * Copyright (C) 2013 Linaro.
   8  * Viresh Kumar <viresh.kumar@linaro.org>
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License version 2 as
  12  * published by the Free Software Foundation.
  13  *
  14  * This program is distributed "as is" WITHOUT ANY WARRANTY of any
  15  * kind, whether express or implied; without even the implied warranty
  16  * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  17  * GNU General Public License for more details.
  18  */
  19
  20 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  21
  22 #include <linux/clk.h>
  23 #include <linux/cpu.h>
  24 #include <linux/cpufreq.h>
  25 #include <linux/cpumask.h>
  26 #include <linux/export.h>
  27 #include <linux/mutex.h>
  28 #include <linux/of_platform.h>
  29 #include <linux/pm_opp.h>
  30 #include <linux/slab.h>
  31 #include <linux/topology.h>
  32 #include <linux/types.h>
  33 #include <asm/bL_switcher.h>
  34
  35 #include "arm_big_little.h"
  36
  37 /* Currently we support only two clusters */
  38 #define A15_CLUSTER     0
  39 #define A7_CLUSTER      1
  40 #define MAX_CLUSTERS    2
  41
  42 #ifdef CONFIG_BL_SWITCHER
  43 static bool bL_switching_enabled;
  44 #define is_bL_switching_enabled()       bL_switching_enabled
  45 #define set_switching_enabled(x)        (bL_switching_enabled = (x))
  46 #else
  47 #define is_bL_switching_enabled()       false
  48 #define set_switching_enabled(x)        do { } while (0)
  49 #endif
  50
  51 #define ACTUAL_FREQ(cluster, freq)  ((cluster == A7_CLUSTER) ? freq << 1 : freq)
  52 #define VIRT_FREQ(cluster, freq)    ((cluster == A7_CLUSTER) ? freq >> 1 : freq)
  53
  54 static struct cpufreq_arm_bL_ops *arm_bL_ops;
  55 static struct clk *clk[MAX_CLUSTERS];
  56 static struct cpufreq_frequency_table *freq_table[MAX_CLUSTERS + 1];
  57 static atomic_t cluster_usage[MAX_CLUSTERS + 1];
  58
  59 static unsigned int clk_big_min;        /* (Big) clock frequencies */
  60 static unsigned int clk_little_max;     /* Maximum clock frequency (Little) */
  61
  62 static DEFINE_PER_CPU(unsigned int, physical_cluster);
  63 static DEFINE_PER_CPU(unsigned int, cpu_last_req_freq);
  64
  65 static struct mutex cluster_lock[MAX_CLUSTERS];
  66
  67 static inline int raw_cpu_to_cluster(int cpu)
  68 {
  69         return topology_physical_package_id(cpu);
  70 }
  71
  72 static inline int cpu_to_cluster(int cpu)
  73 {
  74         return is_bL_switching_enabled() ?
  75                 MAX_CLUSTERS : raw_cpu_to_cluster(cpu);
  76 }
  77
  78 static unsigned int find_cluster_maxfreq(int cluster)
  79 {
  80         int j;
  81         u32 max_freq = 0, cpu_freq;
  82
  83         for_each_online_cpu(j) {
  84                 cpu_freq = per_cpu(cpu_last_req_freq, j);
  85
  86                 if ((cluster == per_cpu(physical_cluster, j)) &&
  87                                 (max_freq < cpu_freq))
  88                         max_freq = cpu_freq;
  89         }
  90
  91         pr_debug("%s: cluster: %d, max freq: %d\n", __func__, cluster,
  92                         max_freq);
  93
  94         return max_freq;
  95 }
  96
  97 static unsigned int clk_get_cpu_rate(unsigned int cpu)
  98 {
  99         u32 cur_cluster = per_cpu(physical_cluster, cpu);
 100         u32 rate = clk_get_rate(clk[cur_cluster]) / 1000;
 101
 102         /* For switcher we use virtual A7 clock rates */
 103         if (is_bL_switching_enabled())
 104                 rate = VIRT_FREQ(cur_cluster, rate);
 105
 106         pr_debug("%s: cpu: %d, cluster: %d, freq: %u\n", __func__, cpu,
 107                         cur_cluster, rate);
 108
 109         return rate;
 110 }
 111
 112 static unsigned int bL_cpufreq_get_rate(unsigned int cpu)
 113 {
 114         if (is_bL_switching_enabled()) {
 115                 pr_debug("%s: freq: %d\n", __func__, per_cpu(cpu_last_req_freq,
 116                                         cpu));
 117
 118                 return per_cpu(cpu_last_req_freq, cpu);
 119         } else {
 120                 return clk_get_cpu_rate(cpu);
 121         }
 122 }
 123
 124 static unsigned int
 125 bL_cpufreq_set_rate(u32 cpu, u32 old_cluster, u32 new_cluster, u32 rate)
 126 {
 127         u32 new_rate, prev_rate;
 128         int ret;
 129         bool bLs = is_bL_switching_enabled();
 130
 131         mutex_lock(&cluster_lock[new_cluster]);
 132
 133         if (bLs) {
 134                 prev_rate = per_cpu(cpu_last_req_freq, cpu);
 135                 per_cpu(cpu_last_req_freq, cpu) = rate;
 136                 per_cpu(physical_cluster, cpu) = new_cluster;
 137
 138                 new_rate = find_cluster_maxfreq(new_cluster);
 139                 new_rate = ACTUAL_FREQ(new_cluster, new_rate);
 140         } else {
 141                 new_rate = rate;
 142         }
 143
 144         pr_debug("%s: cpu: %d, old cluster: %d, new cluster: %d, freq: %d\n",
 145                         __func__, cpu, old_cluster, new_cluster, new_rate);
 146
 147         ret = clk_set_rate(clk[new_cluster], new_rate * 1000);
 148         if (WARN_ON(ret)) {
 149                 pr_err("clk_set_rate failed: %d, new cluster: %d\n", ret,
 150                                 new_cluster);
 151                 if (bLs) {
 152                         per_cpu(cpu_last_req_freq, cpu) = prev_rate;
 153                         per_cpu(physical_cluster, cpu) = old_cluster;
 154                 }
 155
 156                 mutex_unlock(&cluster_lock[new_cluster]);
 157
 158                 return ret;
 159         }
 160
 161         mutex_unlock(&cluster_lock[new_cluster]);
 162
 163         /* Recalc freq for old cluster when switching clusters */
 164         if (old_cluster != new_cluster) {
 165                 pr_debug("%s: cpu: %d, old cluster: %d, new cluster: %d\n",
 166                                 __func__, cpu, old_cluster, new_cluster);
 167
 168                 /* Switch cluster */
 169                 bL_switch_request(cpu, new_cluster);
 170
 171                 mutex_lock(&cluster_lock[old_cluster]);
 172
 173                 /* Set freq of old cluster if there are cpus left on it */
 174                 new_rate = find_cluster_maxfreq(old_cluster);
 175                 new_rate = ACTUAL_FREQ(old_cluster, new_rate);
 176
 177                 if (new_rate) {
 178                         pr_debug("%s: Updating rate of old cluster: %d, to freq: %d\n",
 179                                         __func__, old_cluster, new_rate);
 180
 181                         if (clk_set_rate(clk[old_cluster], new_rate * 1000))
 182                                 pr_err("%s: clk_set_rate failed: %d, old cluster: %d\n",
 183                                                 __func__, ret, old_cluster);
 184                 }
 185                 mutex_unlock(&cluster_lock[old_cluster]);
 186         }
 187
 188         return 0;
 189 }
 190
 191 /* Set clock frequency */
 192 static int bL_cpufreq_set_target(struct cpufreq_policy *policy,
 193                 unsigned int index)
 194 {
 195         struct cpufreq_freqs freqs;
 196         u32 cpu = policy->cpu, cur_cluster, new_cluster, actual_cluster;
 197         int ret = 0;
 198
 199         cur_cluster = cpu_to_cluster(cpu);
 200         new_cluster = actual_cluster = per_cpu(physical_cluster, cpu);
 201
 202         freqs.old = bL_cpufreq_get_rate(cpu);
 203         freqs.new = freq_table[cur_cluster][index].frequency;
 204
 205         pr_debug("%s: cpu: %d, cluster: %d, oldfreq: %d, target freq: %d, new freq: %d\n",
 206                         __func__, cpu, cur_cluster, freqs.old, freqs.new,
 207                         freqs.new);
 208
 209         if (is_bL_switching_enabled()) {
 210                 if ((actual_cluster == A15_CLUSTER) &&
 211                                 (freqs.new < clk_big_min)) {
 212                         new_cluster = A7_CLUSTER;
 213                 } else if ((actual_cluster == A7_CLUSTER) &&
 214                                 (freqs.new > clk_little_max)) {
 215                         new_cluster = A15_CLUSTER;
 216                 }
 217         }
 218
 219         cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE);
 220
 221         ret = bL_cpufreq_set_rate(cpu, actual_cluster, new_cluster, freqs.new);
 222         if (ret)
 223                 freqs.new = freqs.old;
 224
 225         cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);
 226
 227         return ret;
 228 }
 229
 230 static inline u32 get_table_count(struct cpufreq_frequency_table *table)
 231 {
 232         int count;
 233
 234         for (count = 0; table[count].frequency != CPUFREQ_TABLE_END; count++)
 235                 ;
 236
 237         return count;
 238 }
 239
 240 /* get the minimum frequency in the cpufreq_frequency_table */
 241 static inline u32 get_table_min(struct cpufreq_frequency_table *table)
 242 {
 243         int i;
 244         uint32_t min_freq = ~0;
 245         for (i = 0; (table[i].frequency != CPUFREQ_TABLE_END); i++)
 246                 if (table[i].frequency < min_freq)
 247                         min_freq = table[i].frequency;
 248         return min_freq;
 249 }
 250
 251 /* get the maximum frequency in the cpufreq_frequency_table */
 252 static inline u32 get_table_max(struct cpufreq_frequency_table *table)
 253 {
 254         int i;
 255         uint32_t max_freq = 0;
 256         for (i = 0; (table[i].frequency != CPUFREQ_TABLE_END); i++)
 257                 if (table[i].frequency > max_freq)
 258                         max_freq = table[i].frequency;
 259         return max_freq;
 260 }
 261
 262 static int merge_cluster_tables(void)
 263 {
 264         int i, j, k = 0, count = 1;
 265         struct cpufreq_frequency_table *table;
 266
 267         for (i = 0; i < MAX_CLUSTERS; i++)
 268                 count += get_table_count(freq_table[i]);
 269
 270         table = kzalloc(sizeof(*table) * count, GFP_KERNEL);
 271         if (!table)
 272                 return -ENOMEM;
 273
 274         freq_table[MAX_CLUSTERS] = table;
 275
 276         /* Add in reverse order to get freqs in increasing order */
 277         for (i = MAX_CLUSTERS - 1; i >= 0; i--) {
 278                 for (j = 0; freq_table[i][j].frequency != CPUFREQ_TABLE_END;
 279                                 j++) {
 280                         table[k].frequency = VIRT_FREQ(i,
 281                                         freq_table[i][j].frequency);
 282                         pr_debug("%s: index: %d, freq: %d\n", __func__, k,
 283                                         table[k].frequency);
 284                         k++;
 285                 }
 286         }
 287
 288         table[k].driver_data = k;
 289         table[k].frequency = CPUFREQ_TABLE_END;
 290
 291         pr_debug("%s: End, table: %p, count: %d\n", __func__, table, k);
 292
 293         return 0;
 294 }
 295
 296 static void _put_cluster_clk_and_freq_table(struct device *cpu_dev)
 297 {
 298         u32 cluster = raw_cpu_to_cluster(cpu_dev->id);
 299
 300         if (!freq_table[cluster])
 301                 return;
 302
 303         clk_put(clk[cluster]);
 304         dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table[cluster]);
 305         dev_dbg(cpu_dev, "%s: cluster: %d\n", __func__, cluster);
 306 }
 307
 308 static void put_cluster_clk_and_freq_table(struct device *cpu_dev)
 309 {
 310         u32 cluster = cpu_to_cluster(cpu_dev->id);
 311         int i;
 312
 313         if (atomic_dec_return(&cluster_usage[cluster]))
 314                 return;
 315
 316         if (cluster < MAX_CLUSTERS)
 317                 return _put_cluster_clk_and_freq_table(cpu_dev);
 318
 319         for_each_present_cpu(i) {
 320                 struct device *cdev = get_cpu_device(i);
 321                 if (!cdev) {
 322                         pr_err("%s: failed to get cpu%d device\n", __func__, i);
 323                         return;
 324                 }
 325
 326                 _put_cluster_clk_and_freq_table(cdev);
 327         }
 328
 329         /* free virtual table */
 330         kfree(freq_table[cluster]);
 331 }
 332
 333 static int _get_cluster_clk_and_freq_table(struct device *cpu_dev)
 334 {
 335         u32 cluster = raw_cpu_to_cluster(cpu_dev->id);
 336         char name[14] = "cpu-cluster.";
 337         int ret;
 338
 339         if (freq_table[cluster])
 340                 return 0;
 341
 342         ret = arm_bL_ops->init_opp_table(cpu_dev);
 343         if (ret) {
 344                 dev_err(cpu_dev, "%s: init_opp_table failed, cpu: %d, err: %d\n",
 345                                 __func__, cpu_dev->id, ret);
 346                 goto out;
 347         }
 348
 349         ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table[cluster]);
 350         if (ret) {
 351                 dev_err(cpu_dev, "%s: failed to init cpufreq table, cpu: %d, err: %d\n",
 352                                 __func__, cpu_dev->id, ret);
 353                 goto out;
 354         }
 355
 356         name[12] = cluster + '0';
 357         clk[cluster] = clk_get(cpu_dev, name);
 358         if (!IS_ERR(clk[cluster])) {
 359                 dev_dbg(cpu_dev, "%s: clk: %p & freq table: %p, cluster: %d\n",
 360                                 __func__, clk[cluster], freq_table[cluster],
 361                                 cluster);
 362                 return 0;
 363         }
 364
 365         dev_err(cpu_dev, "%s: Failed to get clk for cpu: %d, cluster: %d\n",
 366                         __func__, cpu_dev->id, cluster);
 367         ret = PTR_ERR(clk[cluster]);
 368         dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table[cluster]);
 369
 370 out:
 371         dev_err(cpu_dev, "%s: Failed to get data for cluster: %d\n", __func__,
 372                         cluster);
 373         return ret;
 374 }
 375
 376 static int get_cluster_clk_and_freq_table(struct device *cpu_dev)
 377 {
 378         u32 cluster = cpu_to_cluster(cpu_dev->id);
 379         int i, ret;
 380
 381         if (atomic_inc_return(&cluster_usage[cluster]) != 1)
 382                 return 0;
 383
 384         if (cluster < MAX_CLUSTERS) {
 385                 ret = _get_cluster_clk_and_freq_table(cpu_dev);
 386                 if (ret)
 387                         atomic_dec(&cluster_usage[cluster]);
 388                 return ret;
 389         }
 390
 391         /*
 392          * Get data for all clusters and fill virtual cluster with a merge of
 393          * both
 394          */
 395         for_each_present_cpu(i) {
 396                 struct device *cdev = get_cpu_device(i);
 397                 if (!cdev) {
 398                         pr_err("%s: failed to get cpu%d device\n", __func__, i);
 399                         return -ENODEV;
 400                 }
 401
 402                 ret = _get_cluster_clk_and_freq_table(cdev);
 403                 if (ret)
 404                         goto put_clusters;
 405         }
 406
 407         ret = merge_cluster_tables();
 408         if (ret)
 409                 goto put_clusters;
 410
 411         /* Assuming 2 cluster, set clk_big_min and clk_little_max */
 412         clk_big_min = get_table_min(freq_table[0]);
 413         clk_little_max = VIRT_FREQ(1, get_table_max(freq_table[1]));
 414
 415         pr_debug("%s: cluster: %d, clk_big_min: %d, clk_little_max: %d\n",
 416                         __func__, cluster, clk_big_min, clk_little_max);
 417
 418         return 0;
 419
 420 put_clusters:
 421         for_each_present_cpu(i) {
 422                 struct device *cdev = get_cpu_device(i);
 423                 if (!cdev) {
 424                         pr_err("%s: failed to get cpu%d device\n", __func__, i);
 425                         return -ENODEV;
 426                 }
 427
 428                 _put_cluster_clk_and_freq_table(cdev);
 429         }
 430
 431         atomic_dec(&cluster_usage[cluster]);
 432
 433         return ret;
 434 }
 435
 436 /* Per-CPU initialization */
 437 static int bL_cpufreq_init(struct cpufreq_policy *policy)
 438 {
 439         u32 cur_cluster = cpu_to_cluster(policy->cpu);
 440         struct device *cpu_dev;
 441         int ret;
 442
 443         cpu_dev = get_cpu_device(policy->cpu);
 444         if (!cpu_dev) {
 445                 pr_err("%s: failed to get cpu%d device\n", __func__,
 446                                 policy->cpu);
 447                 return -ENODEV;
 448         }
 449
 450         ret = get_cluster_clk_and_freq_table(cpu_dev);
 451         if (ret)
 452                 return ret;
 453
 454         ret = cpufreq_table_validate_and_show(policy, freq_table[cur_cluster]);
 455         if (ret) {
 456                 dev_err(cpu_dev, "CPU %d, cluster: %d invalid freq table\n",
 457                                 policy->cpu, cur_cluster);
 458                 put_cluster_clk_and_freq_table(cpu_dev);
 459                 return ret;
 460         }
 461
 462         if (cur_cluster < MAX_CLUSTERS) {
 463                 cpumask_copy(policy->cpus, topology_core_cpumask(policy->cpu));
 464
 465                 per_cpu(physical_cluster, policy->cpu) = cur_cluster;
 466         } else {
 467                 /* Assumption: during init, we are always running on A15 */
 468                 per_cpu(physical_cluster, policy->cpu) = A15_CLUSTER;
 469         }
 470
 471         if (arm_bL_ops->get_transition_latency)
 472                 policy->cpuinfo.transition_latency =
 473                         arm_bL_ops->get_transition_latency(cpu_dev);
 474         else
 475                 policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
 476
 477         if (is_bL_switching_enabled())
 478                 per_cpu(cpu_last_req_freq, policy->cpu) = clk_get_cpu_rate(policy->cpu);
 479
 480         dev_info(cpu_dev, "%s: CPU %d initialized\n", __func__, policy->cpu);
 481         return 0;
 482 }
 483
 484 static int bL_cpufreq_exit(struct cpufreq_policy *policy)
 485 {
 486         struct device *cpu_dev;
 487
 488         cpu_dev = get_cpu_device(policy->cpu);
 489         if (!cpu_dev) {
 490                 pr_err("%s: failed to get cpu%d device\n", __func__,
 491                                 policy->cpu);
 492                 return -ENODEV;
 493         }
 494
 495         cpufreq_frequency_table_put_attr(policy->cpu);
 496         put_cluster_clk_and_freq_table(cpu_dev);
 497         dev_dbg(cpu_dev, "%s: Exited, cpu: %d\n", __func__, policy->cpu);
 498
 499         return 0;
 500 }
 501
 502 static struct cpufreq_driver bL_cpufreq_driver = {
 503         .name                   = "arm-big-little",
 504         .flags                  = CPUFREQ_STICKY |
 505                                         CPUFREQ_HAVE_GOVERNOR_PER_POLICY,
 506         .verify                 = cpufreq_generic_frequency_table_verify,
 507         .target_index           = bL_cpufreq_set_target,
 508         .get                    = bL_cpufreq_get_rate,
 509         .init                   = bL_cpufreq_init,
 510         .exit                   = bL_cpufreq_exit,
 511         .attr                   = cpufreq_generic_attr,
 512 };
 513
 514 static int bL_cpufreq_switcher_notifier(struct notifier_block *nfb,
 515                                         unsigned long action, void *_arg)
 516 {
 517         pr_debug("%s: action: %ld\n", __func__, action);
 518
 519         switch (action) {
 520         case BL_NOTIFY_PRE_ENABLE:
 521         case BL_NOTIFY_PRE_DISABLE:
 522                 cpufreq_unregister_driver(&bL_cpufreq_driver);
 523                 break;
 524
 525         case BL_NOTIFY_POST_ENABLE:
 526                 set_switching_enabled(true);
 527                 cpufreq_register_driver(&bL_cpufreq_driver);
 528                 break;
 529
 530         case BL_NOTIFY_POST_DISABLE:
 531                 set_switching_enabled(false);
 532                 cpufreq_register_driver(&bL_cpufreq_driver);
 533                 break;
 534
 535         default:
 536                 return NOTIFY_DONE;
 537         }
 538
 539         return NOTIFY_OK;
 540 }
 541
 542 static struct notifier_block bL_switcher_notifier = {
 543         .notifier_call = bL_cpufreq_switcher_notifier,
 544 };
 545
 546 int bL_cpufreq_register(struct cpufreq_arm_bL_ops *ops)
 547 {
 548         int ret, i;
 549
 550         if (arm_bL_ops) {
 551                 pr_debug("%s: Already registered: %s, exiting\n", __func__,
 552                                 arm_bL_ops->name);
 553                 return -EBUSY;
 554         }
 555
 556         if (!ops || !strlen(ops->name) || !ops->init_opp_table) {
 557                 pr_err("%s: Invalid arm_bL_ops, exiting\n", __func__);
 558                 return -ENODEV;
 559         }
 560
 561         arm_bL_ops = ops;
 562
 563         ret = bL_switcher_get_enabled();
 564         set_switching_enabled(ret);
 565
 566         for (i = 0; i < MAX_CLUSTERS; i++)
 567                 mutex_init(&cluster_lock[i]);
 568
 569         ret = cpufreq_register_driver(&bL_cpufreq_driver);
 570         if (ret) {
 571                 pr_info("%s: Failed registering platform driver: %s, err: %d\n",
 572                                 __func__, ops->name, ret);
 573                 arm_bL_ops = NULL;
 574         } else {
 575                 ret = bL_switcher_register_notifier(&bL_switcher_notifier);
 576                 if (ret) {
 577                         cpufreq_unregister_driver(&bL_cpufreq_driver);
 578                         arm_bL_ops = NULL;
 579                 } else {
 580                         pr_info("%s: Registered platform driver: %s\n",
 581                                         __func__, ops->name);
 582                 }
 583         }
 584
 585         bL_switcher_put_enabled();
 586         return ret;
 587 }
 588 EXPORT_SYMBOL_GPL(bL_cpufreq_register);
 589
 590 void bL_cpufreq_unregister(struct cpufreq_arm_bL_ops *ops)
 591 {
 592         if (arm_bL_ops != ops) {
 593                 pr_err("%s: Registered with: %s, can't unregister, exiting\n",
 594                                 __func__, arm_bL_ops->name);
 595                 return;
 596         }
 597
 598         bL_switcher_get_enabled();
 599         bL_switcher_unregister_notifier(&bL_switcher_notifier);
 600         cpufreq_unregister_driver(&bL_cpufreq_driver);
 601         bL_switcher_put_enabled();
 602         pr_info("%s: Un-registered platform driver: %s\n", __func__,
 603                         arm_bL_ops->name);
 604         arm_bL_ops = NULL;
 605 }
 606 EXPORT_SYMBOL_GPL(bL_cpufreq_unregister);