kernel/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         if (arm_bL_ops->free_opp_table)
 293                 arm_bL_ops->free_opp_table(cpu_dev);
 294         dev_dbg(cpu_dev, "%s: cluster: %d\n", __func__, cluster);
 295 }
 296
 297 static void put_cluster_clk_and_freq_table(struct device *cpu_dev)
 298 {
 299         u32 cluster = cpu_to_cluster(cpu_dev->id);
 300         int i;
 301
 302         if (atomic_dec_return(&cluster_usage[cluster]))
 303                 return;
 304
 305         if (cluster < MAX_CLUSTERS)
 306                 return _put_cluster_clk_and_freq_table(cpu_dev);
 307
 308         for_each_present_cpu(i) {
 309                 struct device *cdev = get_cpu_device(i);
 310                 if (!cdev) {
 311                         pr_err("%s: failed to get cpu%d device\n", __func__, i);
 312                         return;
 313                 }
 314
 315                 _put_cluster_clk_and_freq_table(cdev);
 316         }
 317
 318         /* free virtual table */
 319         kfree(freq_table[cluster]);
 320 }
 321
 322 static int _get_cluster_clk_and_freq_table(struct device *cpu_dev)
 323 {
 324         u32 cluster = raw_cpu_to_cluster(cpu_dev->id);
 325         char name[14] = "cpu-cluster.";
 326         int ret;
 327
 328         if (freq_table[cluster])
 329                 return 0;
 330
 331         ret = arm_bL_ops->init_opp_table(cpu_dev);
 332         if (ret) {
 333                 dev_err(cpu_dev, "%s: init_opp_table failed, cpu: %d, err: %d\n",
 334                                 __func__, cpu_dev->id, ret);
 335                 goto out;
 336         }
 337
 338         ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table[cluster]);
 339         if (ret) {
 340                 dev_err(cpu_dev, "%s: failed to init cpufreq table, cpu: %d, err: %d\n",
 341                                 __func__, cpu_dev->id, ret);
 342                 goto free_opp_table;
 343         }
 344
 345         name[12] = cluster + '0';
 346         clk[cluster] = clk_get(cpu_dev, name);
 347         if (!IS_ERR(clk[cluster])) {
 348                 dev_dbg(cpu_dev, "%s: clk: %p & freq table: %p, cluster: %d\n",
 349                                 __func__, clk[cluster], freq_table[cluster],
 350                                 cluster);
 351                 return 0;
 352         }
 353
 354         dev_err(cpu_dev, "%s: Failed to get clk for cpu: %d, cluster: %d\n",
 355                         __func__, cpu_dev->id, cluster);
 356         ret = PTR_ERR(clk[cluster]);
 357         dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table[cluster]);
 358
 359 free_opp_table:
 360         if (arm_bL_ops->free_opp_table)
 361                 arm_bL_ops->free_opp_table(cpu_dev);
 362 out:
 363         dev_err(cpu_dev, "%s: Failed to get data for cluster: %d\n", __func__,
 364                         cluster);
 365         return ret;
 366 }
 367
 368 static int get_cluster_clk_and_freq_table(struct device *cpu_dev)
 369 {
 370         u32 cluster = cpu_to_cluster(cpu_dev->id);
 371         int i, ret;
 372
 373         if (atomic_inc_return(&cluster_usage[cluster]) != 1)
 374                 return 0;
 375
 376         if (cluster < MAX_CLUSTERS) {
 377                 ret = _get_cluster_clk_and_freq_table(cpu_dev);
 378                 if (ret)
 379                         atomic_dec(&cluster_usage[cluster]);
 380                 return ret;
 381         }
 382
 383         /*
 384          * Get data for all clusters and fill virtual cluster with a merge of
 385          * both
 386          */
 387         for_each_present_cpu(i) {
 388                 struct device *cdev = get_cpu_device(i);
 389                 if (!cdev) {
 390                         pr_err("%s: failed to get cpu%d device\n", __func__, i);
 391                         return -ENODEV;
 392                 }
 393
 394                 ret = _get_cluster_clk_and_freq_table(cdev);
 395                 if (ret)
 396                         goto put_clusters;
 397         }
 398
 399         ret = merge_cluster_tables();
 400         if (ret)
 401                 goto put_clusters;
 402
 403         /* Assuming 2 cluster, set clk_big_min and clk_little_max */
 404         clk_big_min = get_table_min(freq_table[0]);
 405         clk_little_max = VIRT_FREQ(1, get_table_max(freq_table[1]));
 406
 407         pr_debug("%s: cluster: %d, clk_big_min: %d, clk_little_max: %d\n",
 408                         __func__, cluster, clk_big_min, clk_little_max);
 409
 410         return 0;
 411
 412 put_clusters:
 413         for_each_present_cpu(i) {
 414                 struct device *cdev = get_cpu_device(i);
 415                 if (!cdev) {
 416                         pr_err("%s: failed to get cpu%d device\n", __func__, i);
 417                         return -ENODEV;
 418                 }
 419
 420                 _put_cluster_clk_and_freq_table(cdev);
 421         }
 422
 423         atomic_dec(&cluster_usage[cluster]);
 424
 425         return ret;
 426 }
 427
 428 /* Per-CPU initialization */
 429 static int bL_cpufreq_init(struct cpufreq_policy *policy)
 430 {
 431         u32 cur_cluster = cpu_to_cluster(policy->cpu);
 432         struct device *cpu_dev;
 433         int ret;
 434
 435         cpu_dev = get_cpu_device(policy->cpu);
 436         if (!cpu_dev) {
 437                 pr_err("%s: failed to get cpu%d device\n", __func__,
 438                                 policy->cpu);
 439                 return -ENODEV;
 440         }
 441
 442         ret = get_cluster_clk_and_freq_table(cpu_dev);
 443         if (ret)
 444                 return ret;
 445
 446         ret = cpufreq_table_validate_and_show(policy, freq_table[cur_cluster]);
 447         if (ret) {
 448                 dev_err(cpu_dev, "CPU %d, cluster: %d invalid freq table\n",
 449                                 policy->cpu, cur_cluster);
 450                 put_cluster_clk_and_freq_table(cpu_dev);
 451                 return ret;
 452         }
 453
 454         if (cur_cluster < MAX_CLUSTERS) {
 455                 int cpu;
 456
 457                 cpumask_copy(policy->cpus, topology_core_cpumask(policy->cpu));
 458
 459                 for_each_cpu(cpu, policy->cpus)
 460                         per_cpu(physical_cluster, cpu) = cur_cluster;
 461         } else {
 462                 /* Assumption: during init, we are always running on A15 */
 463                 per_cpu(physical_cluster, policy->cpu) = A15_CLUSTER;
 464         }
 465
 466         if (arm_bL_ops->get_transition_latency)
 467                 policy->cpuinfo.transition_latency =
 468                         arm_bL_ops->get_transition_latency(cpu_dev);
 469         else
 470                 policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
 471
 472         if (is_bL_switching_enabled())
 473                 per_cpu(cpu_last_req_freq, policy->cpu) = clk_get_cpu_rate(policy->cpu);
 474
 475         dev_info(cpu_dev, "%s: CPU %d initialized\n", __func__, policy->cpu);
 476         return 0;
 477 }
 478
 479 static int bL_cpufreq_exit(struct cpufreq_policy *policy)
 480 {
 481         struct device *cpu_dev;
 482
 483         cpu_dev = get_cpu_device(policy->cpu);
 484         if (!cpu_dev) {
 485                 pr_err("%s: failed to get cpu%d device\n", __func__,
 486                                 policy->cpu);
 487                 return -ENODEV;
 488         }
 489
 490         put_cluster_clk_and_freq_table(cpu_dev);
 491         dev_dbg(cpu_dev, "%s: Exited, cpu: %d\n", __func__, policy->cpu);
 492
 493         return 0;
 494 }
 495
 496 static struct cpufreq_driver bL_cpufreq_driver = {
 497         .name                   = "arm-big-little",
 498         .flags                  = CPUFREQ_STICKY |
 499                                         CPUFREQ_HAVE_GOVERNOR_PER_POLICY |
 500                                         CPUFREQ_NEED_INITIAL_FREQ_CHECK,
 501         .verify                 = cpufreq_generic_frequency_table_verify,
 502         .target_index           = bL_cpufreq_set_target,
 503         .get                    = bL_cpufreq_get_rate,
 504         .init                   = bL_cpufreq_init,
 505         .exit                   = bL_cpufreq_exit,
 506         .attr                   = cpufreq_generic_attr,
 507 };
 508
 509 static int bL_cpufreq_switcher_notifier(struct notifier_block *nfb,
 510                                         unsigned long action, void *_arg)
 511 {
 512         pr_debug("%s: action: %ld\n", __func__, action);
 513
 514         switch (action) {
 515         case BL_NOTIFY_PRE_ENABLE:
 516         case BL_NOTIFY_PRE_DISABLE:
 517                 cpufreq_unregister_driver(&bL_cpufreq_driver);
 518                 break;
 519
 520         case BL_NOTIFY_POST_ENABLE:
 521                 set_switching_enabled(true);
 522                 cpufreq_register_driver(&bL_cpufreq_driver);
 523                 break;
 524
 525         case BL_NOTIFY_POST_DISABLE:
 526                 set_switching_enabled(false);
 527                 cpufreq_register_driver(&bL_cpufreq_driver);
 528                 break;
 529
 530         default:
 531                 return NOTIFY_DONE;
 532         }
 533
 534         return NOTIFY_OK;
 535 }
 536
 537 static struct notifier_block bL_switcher_notifier = {
 538         .notifier_call = bL_cpufreq_switcher_notifier,
 539 };
 540
 541 int bL_cpufreq_register(struct cpufreq_arm_bL_ops *ops)
 542 {
 543         int ret, i;
 544
 545         if (arm_bL_ops) {
 546                 pr_debug("%s: Already registered: %s, exiting\n", __func__,
 547                                 arm_bL_ops->name);
 548                 return -EBUSY;
 549         }
 550
 551         if (!ops || !strlen(ops->name) || !ops->init_opp_table) {
 552                 pr_err("%s: Invalid arm_bL_ops, exiting\n", __func__);
 553                 return -ENODEV;
 554         }
 555
 556         arm_bL_ops = ops;
 557
 558         ret = bL_switcher_get_enabled();
 559         set_switching_enabled(ret);
 560
 561         for (i = 0; i < MAX_CLUSTERS; i++)
 562                 mutex_init(&cluster_lock[i]);
 563
 564         ret = cpufreq_register_driver(&bL_cpufreq_driver);
 565         if (ret) {
 566                 pr_info("%s: Failed registering platform driver: %s, err: %d\n",
 567                                 __func__, ops->name, ret);
 568                 arm_bL_ops = NULL;
 569         } else {
 570                 ret = bL_switcher_register_notifier(&bL_switcher_notifier);
 571                 if (ret) {
 572                         cpufreq_unregister_driver(&bL_cpufreq_driver);
 573                         arm_bL_ops = NULL;
 574                 } else {
 575                         pr_info("%s: Registered platform driver: %s\n",
 576                                         __func__, ops->name);
 577                 }
 578         }
 579
 580         bL_switcher_put_enabled();
 581         return ret;
 582 }
 583 EXPORT_SYMBOL_GPL(bL_cpufreq_register);
 584
 585 void bL_cpufreq_unregister(struct cpufreq_arm_bL_ops *ops)
 586 {
 587         if (arm_bL_ops != ops) {
 588                 pr_err("%s: Registered with: %s, can't unregister, exiting\n",
 589                                 __func__, arm_bL_ops->name);
 590                 return;
 591         }
 592
 593         bL_switcher_get_enabled();
 594         bL_switcher_unregister_notifier(&bL_switcher_notifier);
 595         cpufreq_unregister_driver(&bL_cpufreq_driver);
 596         bL_switcher_put_enabled();
 597         pr_info("%s: Un-registered platform driver: %s\n", __func__,
 598                         arm_bL_ops->name);
 599         arm_bL_ops = NULL;
 600 }
 601 EXPORT_SYMBOL_GPL(bL_cpufreq_unregister);
 602
 603 MODULE_AUTHOR("Viresh Kumar <viresh.kumar@linaro.org>");
 604 MODULE_DESCRIPTION("Generic ARM big LITTLE cpufreq driver");
 605 MODULE_LICENSE("GPL v2");