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/module.h>
  28 #include <linux/mutex.h>
  29 #include <linux/of_platform.h>
  30 #include <linux/pm_opp.h>
  31 #include <linux/slab.h>
  32 #include <linux/topology.h>
  33 #include <linux/types.h>
  34 #include <asm/bL_switcher.h>
  35
  36 #include "arm_big_little.h"
  37
  38 /* Currently we support only two clusters */
  39 #define A15_CLUSTER     0
  40 #define A7_CLUSTER      1
  41 #define MAX_CLUSTERS    2
  42
  43 #ifdef CONFIG_BL_SWITCHER
  44 static bool bL_switching_enabled;
  45 #define is_bL_switching_enabled()       bL_switching_enabled
  46 #define set_switching_enabled(x)        (bL_switching_enabled = (x))
  47 #else
  48 #define is_bL_switching_enabled()       false
  49 #define set_switching_enabled(x)        do { } while (0)
  50 #endif
  51
  52 #define ACTUAL_FREQ(cluster, freq)  ((cluster == A7_CLUSTER) ? freq << 1 : freq)
  53 #define VIRT_FREQ(cluster, freq)    ((cluster == A7_CLUSTER) ? freq >> 1 : freq)
  54
  55 static struct cpufreq_arm_bL_ops *arm_bL_ops;
  56 static struct clk *clk[MAX_CLUSTERS];
  57 static struct cpufreq_frequency_table *freq_table[MAX_CLUSTERS + 1];
  58 static atomic_t cluster_usage[MAX_CLUSTERS + 1];
  59
  60 static unsigned int clk_big_min;        /* (Big) clock frequencies */
  61 static unsigned int clk_little_max;     /* Maximum clock frequency (Little) */
  62
  63 static DEFINE_PER_CPU(unsigned int, physical_cluster);
  64 static DEFINE_PER_CPU(unsigned int, cpu_last_req_freq);
  65
  66 static struct mutex cluster_lock[MAX_CLUSTERS];
  67
  68 static inline int raw_cpu_to_cluster(int cpu)
  69 {
  70         return topology_physical_package_id(cpu);
  71 }
  72
  73 static inline int cpu_to_cluster(int cpu)
  74 {
  75         return is_bL_switching_enabled() ?
  76                 MAX_CLUSTERS : raw_cpu_to_cluster(cpu);
  77 }
  78
  79 static unsigned int find_cluster_maxfreq(int cluster)
  80 {
  81         int j;
  82         u32 max_freq = 0, cpu_freq;
  83
  84         for_each_online_cpu(j) {
  85                 cpu_freq = per_cpu(cpu_last_req_freq, j);
  86
  87                 if ((cluster == per_cpu(physical_cluster, j)) &&
  88                                 (max_freq < cpu_freq))
  89                         max_freq = cpu_freq;
  90         }
  91
  92         pr_debug("%s: cluster: %d, max freq: %d\n", __func__, cluster,
  93                         max_freq);
  94
  95         return max_freq;
  96 }
  97
  98 static unsigned int clk_get_cpu_rate(unsigned int cpu)
  99 {
 100         u32 cur_cluster = per_cpu(physical_cluster, cpu);
 101         u32 rate = clk_get_rate(clk[cur_cluster]) / 1000;
 102
 103         /* For switcher we use virtual A7 clock rates */
 104         if (is_bL_switching_enabled())
 105                 rate = VIRT_FREQ(cur_cluster, rate);
 106
 107         pr_debug("%s: cpu: %d, cluster: %d, freq: %u\n", __func__, cpu,
 108                         cur_cluster, rate);
 109
 110         return rate;
 111 }
 112
 113 static unsigned int bL_cpufreq_get_rate(unsigned int cpu)
 114 {
 115         if (is_bL_switching_enabled()) {
 116                 pr_debug("%s: freq: %d\n", __func__, per_cpu(cpu_last_req_freq,
 117                                         cpu));
 118
 119                 return per_cpu(cpu_last_req_freq, cpu);
 120         } else {
 121                 return clk_get_cpu_rate(cpu);
 122         }
 123 }
 124
 125 static unsigned int
 126 bL_cpufreq_set_rate(u32 cpu, u32 old_cluster, u32 new_cluster, u32 rate)
 127 {
 128         u32 new_rate, prev_rate;
 129         int ret;
 130         bool bLs = is_bL_switching_enabled();
 131
 132         mutex_lock(&cluster_lock[new_cluster]);
 133
 134         if (bLs) {
 135                 prev_rate = per_cpu(cpu_last_req_freq, cpu);
 136                 per_cpu(cpu_last_req_freq, cpu) = rate;
 137                 per_cpu(physical_cluster, cpu) = new_cluster;
 138
 139                 new_rate = find_cluster_maxfreq(new_cluster);
 140                 new_rate = ACTUAL_FREQ(new_cluster, new_rate);
 141         } else {
 142                 new_rate = rate;
 143         }
 144
 145         pr_debug("%s: cpu: %d, old cluster: %d, new cluster: %d, freq: %d\n",
 146                         __func__, cpu, old_cluster, new_cluster, new_rate);
 147
 148         ret = clk_set_rate(clk[new_cluster], new_rate * 1000);
 149         if (WARN_ON(ret)) {
 150                 pr_err("clk_set_rate failed: %d, new cluster: %d\n", ret,
 151                                 new_cluster);
 152                 if (bLs) {
 153                         per_cpu(cpu_last_req_freq, cpu) = prev_rate;
 154                         per_cpu(physical_cluster, cpu) = old_cluster;
 155                 }
 156
 157                 mutex_unlock(&cluster_lock[new_cluster]);
 158
 159                 return ret;
 160         }
 161
 162         mutex_unlock(&cluster_lock[new_cluster]);
 163
 164         /* Recalc freq for old cluster when switching clusters */
 165         if (old_cluster != new_cluster) {
 166                 pr_debug("%s: cpu: %d, old cluster: %d, new cluster: %d\n",
 167                                 __func__, cpu, old_cluster, new_cluster);
 168
 169                 /* Switch cluster */
 170                 bL_switch_request(cpu, new_cluster);
 171
 172                 mutex_lock(&cluster_lock[old_cluster]);
 173
 174                 /* Set freq of old cluster if there are cpus left on it */
 175                 new_rate = find_cluster_maxfreq(old_cluster);
 176                 new_rate = ACTUAL_FREQ(old_cluster, new_rate);
 177
 178                 if (new_rate) {
 179                         pr_debug("%s: Updating rate of old cluster: %d, to freq: %d\n",
 180                                         __func__, old_cluster, new_rate);
 181
 182                         if (clk_set_rate(clk[old_cluster], new_rate * 1000))
 183                                 pr_err("%s: clk_set_rate failed: %d, old cluster: %d\n",
 184                                                 __func__, ret, old_cluster);
 185                 }
 186                 mutex_unlock(&cluster_lock[old_cluster]);
 187         }
 188
 189         return 0;
 190 }
 191
 192 /* Set clock frequency */
 193 static int bL_cpufreq_set_target(struct cpufreq_policy *policy,
 194                 unsigned int index)
 195 {
 196         u32 cpu = policy->cpu, cur_cluster, new_cluster, actual_cluster;
 197         unsigned int freqs_new;
 198
 199         cur_cluster = cpu_to_cluster(cpu);
 200         new_cluster = actual_cluster = per_cpu(physical_cluster, cpu);
 201
 202         freqs_new = freq_table[cur_cluster][index].frequency;
 203
 204         if (is_bL_switching_enabled()) {
 205                 if ((actual_cluster == A15_CLUSTER) &&
 206                                 (freqs_new < clk_big_min)) {
 207                         new_cluster = A7_CLUSTER;
 208                 } else if ((actual_cluster == A7_CLUSTER) &&
 209                                 (freqs_new > clk_little_max)) {
 210                         new_cluster = A15_CLUSTER;
 211                 }
 212         }
 213
 214         return bL_cpufreq_set_rate(cpu, actual_cluster, new_cluster, freqs_new);
 215 }
 216
 217 static inline u32 get_table_count(struct cpufreq_frequency_table *table)
 218 {
 219         int count;
 220
 221         for (count = 0; table[count].frequency != CPUFREQ_TABLE_END; count++)
 222                 ;
 223
 224         return count;
 225 }
 226
 227 /* get the minimum frequency in the cpufreq_frequency_table */
 228 static inline u32 get_table_min(struct cpufreq_frequency_table *table)
 229 {
 230         struct cpufreq_frequency_table *pos;
 231         uint32_t min_freq = ~0;
 232         cpufreq_for_each_entry(pos, table)
 233                 if (pos->frequency < min_freq)
 234                         min_freq = pos->frequency;
 235         return min_freq;
 236 }
 237
 238 /* get the maximum frequency in the cpufreq_frequency_table */
 239 static inline u32 get_table_max(struct cpufreq_frequency_table *table)
 240 {
 241         struct cpufreq_frequency_table *pos;
 242         uint32_t max_freq = 0;
 243         cpufreq_for_each_entry(pos, table)
 244                 if (pos->frequency > max_freq)
 245                         max_freq = pos->frequency;
 246         return max_freq;
 247 }
 248
 249 static int merge_cluster_tables(void)
 250 {
 251         int i, j, k = 0, count = 1;
 252         struct cpufreq_frequency_table *table;
 253
 254         for (i = 0; i < MAX_CLUSTERS; i++)
 255                 count += get_table_count(freq_table[i]);
 256
 257         table = kzalloc(sizeof(*table) * count, GFP_KERNEL);
 258         if (!table)
 259                 return -ENOMEM;
 260
 261         freq_table[MAX_CLUSTERS] = table;
 262
 263         /* Add in reverse order to get freqs in increasing order */
 264         for (i = MAX_CLUSTERS - 1; i >= 0; i--) {
 265                 for (j = 0; freq_table[i][j].frequency != CPUFREQ_TABLE_END;
 266                                 j++) {
 267                         table[k].frequency = VIRT_FREQ(i,
 268                                         freq_table[i][j].frequency);
 269                         pr_debug("%s: index: %d, freq: %d\n", __func__, k,
 270                                         table[k].frequency);
 271                         k++;
 272                 }
 273         }
 274
 275         table[k].driver_data = k;
 276         table[k].frequency = CPUFREQ_TABLE_END;
 277
 278         pr_debug("%s: End, table: %p, count: %d\n", __func__, table, k);
 279
 280         return 0;
 281 }
 282
 283 static void _put_cluster_clk_and_freq_table(struct device *cpu_dev)
 284 {
 285         u32 cluster = raw_cpu_to_cluster(cpu_dev->id);
 286
 287         if (!freq_table[cluster])
 288                 return;
 289
 290         clk_put(clk[cluster]);
 291         dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table[cluster]);
 292         dev_dbg(cpu_dev, "%s: cluster: %d\n", __func__, cluster);
 293 }
 294
 295 static void put_cluster_clk_and_freq_table(struct device *cpu_dev)
 296 {
 297         u32 cluster = cpu_to_cluster(cpu_dev->id);
 298         int i;
 299
 300         if (atomic_dec_return(&cluster_usage[cluster]))
 301                 return;
 302
 303         if (cluster < MAX_CLUSTERS)
 304                 return _put_cluster_clk_and_freq_table(cpu_dev);
 305
 306         for_each_present_cpu(i) {
 307                 struct device *cdev = get_cpu_device(i);
 308                 if (!cdev) {
 309                         pr_err("%s: failed to get cpu%d device\n", __func__, i);
 310                         return;
 311                 }
 312
 313                 _put_cluster_clk_and_freq_table(cdev);
 314         }
 315
 316         /* free virtual table */
 317         kfree(freq_table[cluster]);
 318 }
 319
 320 static int _get_cluster_clk_and_freq_table(struct device *cpu_dev)
 321 {
 322         u32 cluster = raw_cpu_to_cluster(cpu_dev->id);
 323         char name[14] = "cpu-cluster.";
 324         int ret;
 325
 326         if (freq_table[cluster])
 327                 return 0;
 328
 329         ret = arm_bL_ops->init_opp_table(cpu_dev);
 330         if (ret) {
 331                 dev_err(cpu_dev, "%s: init_opp_table failed, cpu: %d, err: %d\n",
 332                                 __func__, cpu_dev->id, ret);
 333                 goto out;
 334         }
 335
 336         ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table[cluster]);
 337         if (ret) {
 338                 dev_err(cpu_dev, "%s: failed to init cpufreq table, cpu: %d, err: %d\n",
 339                                 __func__, cpu_dev->id, ret);
 340                 goto out;
 341         }
 342
 343         name[12] = cluster + '0';
 344         clk[cluster] = clk_get(cpu_dev, name);
 345         if (!IS_ERR(clk[cluster])) {
 346                 dev_dbg(cpu_dev, "%s: clk: %p & freq table: %p, cluster: %d\n",
 347                                 __func__, clk[cluster], freq_table[cluster],
 348                                 cluster);
 349                 return 0;
 350         }
 351
 352         dev_err(cpu_dev, "%s: Failed to get clk for cpu: %d, cluster: %d\n",
 353                         __func__, cpu_dev->id, cluster);
 354         ret = PTR_ERR(clk[cluster]);
 355         dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table[cluster]);
 356
 357 out:
 358         dev_err(cpu_dev, "%s: Failed to get data for cluster: %d\n", __func__,
 359                         cluster);
 360         return ret;
 361 }
 362
 363 static int get_cluster_clk_and_freq_table(struct device *cpu_dev)
 364 {
 365         u32 cluster = cpu_to_cluster(cpu_dev->id);
 366         int i, ret;
 367
 368         if (atomic_inc_return(&cluster_usage[cluster]) != 1)
 369                 return 0;
 370
 371         if (cluster < MAX_CLUSTERS) {
 372                 ret = _get_cluster_clk_and_freq_table(cpu_dev);
 373                 if (ret)
 374                         atomic_dec(&cluster_usage[cluster]);
 375                 return ret;
 376         }
 377
 378         /*
 379          * Get data for all clusters and fill virtual cluster with a merge of
 380          * both
 381          */
 382         for_each_present_cpu(i) {
 383                 struct device *cdev = get_cpu_device(i);
 384                 if (!cdev) {
 385                         pr_err("%s: failed to get cpu%d device\n", __func__, i);
 386                         return -ENODEV;
 387                 }
 388
 389                 ret = _get_cluster_clk_and_freq_table(cdev);
 390                 if (ret)
 391                         goto put_clusters;
 392         }
 393
 394         ret = merge_cluster_tables();
 395         if (ret)
 396                 goto put_clusters;
 397
 398         /* Assuming 2 cluster, set clk_big_min and clk_little_max */
 399         clk_big_min = get_table_min(freq_table[0]);
 400         clk_little_max = VIRT_FREQ(1, get_table_max(freq_table[1]));
 401
 402         pr_debug("%s: cluster: %d, clk_big_min: %d, clk_little_max: %d\n",
 403                         __func__, cluster, clk_big_min, clk_little_max);
 404
 405         return 0;
 406
 407 put_clusters:
 408         for_each_present_cpu(i) {
 409                 struct device *cdev = get_cpu_device(i);
 410                 if (!cdev) {
 411                         pr_err("%s: failed to get cpu%d device\n", __func__, i);
 412                         return -ENODEV;
 413                 }
 414
 415                 _put_cluster_clk_and_freq_table(cdev);
 416         }
 417
 418         atomic_dec(&cluster_usage[cluster]);
 419
 420         return ret;
 421 }
 422
 423 /* Per-CPU initialization */
 424 static int bL_cpufreq_init(struct cpufreq_policy *policy)
 425 {
 426         u32 cur_cluster = cpu_to_cluster(policy->cpu);
 427         struct device *cpu_dev;
 428         int ret;
 429
 430         cpu_dev = get_cpu_device(policy->cpu);
 431         if (!cpu_dev) {
 432                 pr_err("%s: failed to get cpu%d device\n", __func__,
 433                                 policy->cpu);
 434                 return -ENODEV;
 435         }
 436
 437         ret = get_cluster_clk_and_freq_table(cpu_dev);
 438         if (ret)
 439                 return ret;
 440
 441         ret = cpufreq_table_validate_and_show(policy, freq_table[cur_cluster]);
 442         if (ret) {
 443                 dev_err(cpu_dev, "CPU %d, cluster: %d invalid freq table\n",
 444                                 policy->cpu, cur_cluster);
 445                 put_cluster_clk_and_freq_table(cpu_dev);
 446                 return ret;
 447         }
 448
 449         if (cur_cluster < MAX_CLUSTERS) {
 450                 int cpu;
 451
 452                 cpumask_copy(policy->cpus, topology_core_cpumask(policy->cpu));
 453
 454                 for_each_cpu(cpu, policy->cpus)
 455                         per_cpu(physical_cluster, cpu) = cur_cluster;
 456         } else {
 457                 /* Assumption: during init, we are always running on A15 */
 458                 per_cpu(physical_cluster, policy->cpu) = A15_CLUSTER;
 459         }
 460
 461         if (arm_bL_ops->get_transition_latency)
 462                 policy->cpuinfo.transition_latency =
 463                         arm_bL_ops->get_transition_latency(cpu_dev);
 464         else
 465                 policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
 466
 467         if (is_bL_switching_enabled())
 468                 per_cpu(cpu_last_req_freq, policy->cpu) = clk_get_cpu_rate(policy->cpu);
 469
 470         dev_info(cpu_dev, "%s: CPU %d initialized\n", __func__, policy->cpu);
 471         return 0;
 472 }
 473
 474 static int bL_cpufreq_exit(struct cpufreq_policy *policy)
 475 {
 476         struct device *cpu_dev;
 477
 478         cpu_dev = get_cpu_device(policy->cpu);
 479         if (!cpu_dev) {
 480                 pr_err("%s: failed to get cpu%d device\n", __func__,
 481                                 policy->cpu);
 482                 return -ENODEV;
 483         }
 484
 485         put_cluster_clk_and_freq_table(cpu_dev);
 486         dev_dbg(cpu_dev, "%s: Exited, cpu: %d\n", __func__, policy->cpu);
 487
 488         return 0;
 489 }
 490
 491 static struct cpufreq_driver bL_cpufreq_driver = {
 492         .name                   = "arm-big-little",
 493         .flags                  = CPUFREQ_STICKY |
 494                                         CPUFREQ_HAVE_GOVERNOR_PER_POLICY |
 495                                         CPUFREQ_NEED_INITIAL_FREQ_CHECK,
 496         .verify                 = cpufreq_generic_frequency_table_verify,
 497         .target_index           = bL_cpufreq_set_target,
 498         .get                    = bL_cpufreq_get_rate,
 499         .init                   = bL_cpufreq_init,
 500         .exit                   = bL_cpufreq_exit,
 501         .attr                   = cpufreq_generic_attr,
 502 };
 503
 504 static int bL_cpufreq_switcher_notifier(struct notifier_block *nfb,
 505                                         unsigned long action, void *_arg)
 506 {
 507         pr_debug("%s: action: %ld\n", __func__, action);
 508
 509         switch (action) {
 510         case BL_NOTIFY_PRE_ENABLE:
 511         case BL_NOTIFY_PRE_DISABLE:
 512                 cpufreq_unregister_driver(&bL_cpufreq_driver);
 513                 break;
 514
 515         case BL_NOTIFY_POST_ENABLE:
 516                 set_switching_enabled(true);
 517                 cpufreq_register_driver(&bL_cpufreq_driver);
 518                 break;
 519
 520         case BL_NOTIFY_POST_DISABLE:
 521                 set_switching_enabled(false);
 522                 cpufreq_register_driver(&bL_cpufreq_driver);
 523                 break;
 524
 525         default:
 526                 return NOTIFY_DONE;
 527         }
 528
 529         return NOTIFY_OK;
 530 }
 531
 532 static struct notifier_block bL_switcher_notifier = {
 533         .notifier_call = bL_cpufreq_switcher_notifier,
 534 };
 535
 536 int bL_cpufreq_register(struct cpufreq_arm_bL_ops *ops)
 537 {
 538         int ret, i;
 539
 540         if (arm_bL_ops) {
 541                 pr_debug("%s: Already registered: %s, exiting\n", __func__,
 542                                 arm_bL_ops->name);
 543                 return -EBUSY;
 544         }
 545
 546         if (!ops || !strlen(ops->name) || !ops->init_opp_table) {
 547                 pr_err("%s: Invalid arm_bL_ops, exiting\n", __func__);
 548                 return -ENODEV;
 549         }
 550
 551         arm_bL_ops = ops;
 552
 553         ret = bL_switcher_get_enabled();
 554         set_switching_enabled(ret);
 555
 556         for (i = 0; i < MAX_CLUSTERS; i++)
 557                 mutex_init(&cluster_lock[i]);
 558
 559         ret = cpufreq_register_driver(&bL_cpufreq_driver);
 560         if (ret) {
 561                 pr_info("%s: Failed registering platform driver: %s, err: %d\n",
 562                                 __func__, ops->name, ret);
 563                 arm_bL_ops = NULL;
 564         } else {
 565                 ret = bL_switcher_register_notifier(&bL_switcher_notifier);
 566                 if (ret) {
 567                         cpufreq_unregister_driver(&bL_cpufreq_driver);
 568                         arm_bL_ops = NULL;
 569                 } else {
 570                         pr_info("%s: Registered platform driver: %s\n",
 571                                         __func__, ops->name);
 572                 }
 573         }
 574
 575         bL_switcher_put_enabled();
 576         return ret;
 577 }
 578 EXPORT_SYMBOL_GPL(bL_cpufreq_register);
 579
 580 void bL_cpufreq_unregister(struct cpufreq_arm_bL_ops *ops)
 581 {
 582         if (arm_bL_ops != ops) {
 583                 pr_err("%s: Registered with: %s, can't unregister, exiting\n",
 584                                 __func__, arm_bL_ops->name);
 585                 return;
 586         }
 587
 588         bL_switcher_get_enabled();
 589         bL_switcher_unregister_notifier(&bL_switcher_notifier);
 590         cpufreq_unregister_driver(&bL_cpufreq_driver);
 591         bL_switcher_put_enabled();
 592         pr_info("%s: Un-registered platform driver: %s\n", __func__,
 593                         arm_bL_ops->name);
 594         arm_bL_ops = NULL;
 595 }
 596 EXPORT_SYMBOL_GPL(bL_cpufreq_unregister);
 597
 598 MODULE_AUTHOR("Viresh Kumar <viresh.kumar@linaro.org>");
 599 MODULE_DESCRIPTION("Generic ARM big LITTLE cpufreq driver");
 600 MODULE_LICENSE("GPL v2");