drivers/cpufreq/vexpress-spc-cpufreq.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Versatile Express SPC CPUFreq Interface driver
   4  *
   5  * Copyright (C) 2013 - 2019 ARM Ltd.
   6  * Sudeep Holla <sudeep.holla@arm.com>
   7  *
   8  * Copyright (C) 2013 Linaro.
   9  * Viresh Kumar <viresh.kumar@linaro.org>
  10  */
  11
  12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  13
  14 #include <linux/clk.h>
  15 #include <linux/cpu.h>
  16 #include <linux/cpufreq.h>
  17 #include <linux/cpumask.h>
  18 #include <linux/cpu_cooling.h>
  19 #include <linux/device.h>
  20 #include <linux/module.h>
  21 #include <linux/mutex.h>
  22 #include <linux/of_platform.h>
  23 #include <linux/platform_device.h>
  24 #include <linux/pm_opp.h>
  25 #include <linux/slab.h>
  26 #include <linux/topology.h>
  27 #include <linux/types.h>
  28
  29 /* Currently we support only two clusters */
  30 #define A15_CLUSTER     0
  31 #define A7_CLUSTER      1
  32 #define MAX_CLUSTERS    2
  33
  34 #ifdef CONFIG_BL_SWITCHER
  35 #include <asm/bL_switcher.h>
  36 static bool bL_switching_enabled;
  37 #define is_bL_switching_enabled()       bL_switching_enabled
  38 #define set_switching_enabled(x)        (bL_switching_enabled = (x))
  39 #else
  40 #define is_bL_switching_enabled()       false
  41 #define set_switching_enabled(x)        do { } while (0)
  42 #define bL_switch_request(...)          do { } while (0)
  43 #define bL_switcher_put_enabled()       do { } while (0)
  44 #define bL_switcher_get_enabled()       do { } while (0)
  45 #endif
  46
  47 #define ACTUAL_FREQ(cluster, freq)  ((cluster == A7_CLUSTER) ? freq << 1 : freq)
  48 #define VIRT_FREQ(cluster, freq)    ((cluster == A7_CLUSTER) ? freq >> 1 : freq)
  49
  50 static struct thermal_cooling_device *cdev[MAX_CLUSTERS];
  51 static struct clk *clk[MAX_CLUSTERS];
  52 static struct cpufreq_frequency_table *freq_table[MAX_CLUSTERS + 1];
  53 static atomic_t cluster_usage[MAX_CLUSTERS + 1];
  54
  55 static unsigned int clk_big_min;        /* (Big) clock frequencies */
  56 static unsigned int clk_little_max;     /* Maximum clock frequency (Little) */
  57
  58 static DEFINE_PER_CPU(unsigned int, physical_cluster);
  59 static DEFINE_PER_CPU(unsigned int, cpu_last_req_freq);
  60
  61 static struct mutex cluster_lock[MAX_CLUSTERS];
  62
  63 static inline int raw_cpu_to_cluster(int cpu)
  64 {
  65         return topology_physical_package_id(cpu);
  66 }
  67
  68 static inline int cpu_to_cluster(int cpu)
  69 {
  70         return is_bL_switching_enabled() ?
  71                 MAX_CLUSTERS : raw_cpu_to_cluster(cpu);
  72 }
  73
  74 static unsigned int find_cluster_maxfreq(int cluster)
  75 {
  76         int j;
  77         u32 max_freq = 0, cpu_freq;
  78
  79         for_each_online_cpu(j) {
  80                 cpu_freq = per_cpu(cpu_last_req_freq, j);
  81
  82                 if (cluster == per_cpu(physical_cluster, j) &&
  83                     max_freq < cpu_freq)
  84                         max_freq = cpu_freq;
  85         }
  86
  87         return max_freq;
  88 }
  89
  90 static unsigned int clk_get_cpu_rate(unsigned int cpu)
  91 {
  92         u32 cur_cluster = per_cpu(physical_cluster, cpu);
  93         u32 rate = clk_get_rate(clk[cur_cluster]) / 1000;
  94
  95         /* For switcher we use virtual A7 clock rates */
  96         if (is_bL_switching_enabled())
  97                 rate = VIRT_FREQ(cur_cluster, rate);
  98
  99         return rate;
 100 }
 101
 102 static unsigned int ve_spc_cpufreq_get_rate(unsigned int cpu)
 103 {
 104         if (is_bL_switching_enabled())
 105                 return per_cpu(cpu_last_req_freq, cpu);
 106         else
 107                 return clk_get_cpu_rate(cpu);
 108 }
 109
 110 static unsigned int
 111 ve_spc_cpufreq_set_rate(u32 cpu, u32 old_cluster, u32 new_cluster, u32 rate)
 112 {
 113         u32 new_rate, prev_rate;
 114         int ret;
 115         bool bLs = is_bL_switching_enabled();
 116
 117         mutex_lock(&cluster_lock[new_cluster]);
 118
 119         if (bLs) {
 120                 prev_rate = per_cpu(cpu_last_req_freq, cpu);
 121                 per_cpu(cpu_last_req_freq, cpu) = rate;
 122                 per_cpu(physical_cluster, cpu) = new_cluster;
 123
 124                 new_rate = find_cluster_maxfreq(new_cluster);
 125                 new_rate = ACTUAL_FREQ(new_cluster, new_rate);
 126         } else {
 127                 new_rate = rate;
 128         }
 129
 130         ret = clk_set_rate(clk[new_cluster], new_rate * 1000);
 131         if (!ret) {
 132                 /*
 133                  * FIXME: clk_set_rate hasn't returned an error here however it
 134                  * may be that clk_change_rate failed due to hardware or
 135                  * firmware issues and wasn't able to report that due to the
 136                  * current design of the clk core layer. To work around this
 137                  * problem we will read back the clock rate and check it is
 138                  * correct. This needs to be removed once clk core is fixed.
 139                  */
 140                 if (clk_get_rate(clk[new_cluster]) != new_rate * 1000)
 141                         ret = -EIO;
 142         }
 143
 144         if (WARN_ON(ret)) {
 145                 if (bLs) {
 146                         per_cpu(cpu_last_req_freq, cpu) = prev_rate;
 147                         per_cpu(physical_cluster, cpu) = old_cluster;
 148                 }
 149
 150                 mutex_unlock(&cluster_lock[new_cluster]);
 151
 152                 return ret;
 153         }
 154
 155         mutex_unlock(&cluster_lock[new_cluster]);
 156
 157         /* Recalc freq for old cluster when switching clusters */
 158         if (old_cluster != new_cluster) {
 159                 /* Switch cluster */
 160                 bL_switch_request(cpu, new_cluster);
 161
 162                 mutex_lock(&cluster_lock[old_cluster]);
 163
 164                 /* Set freq of old cluster if there are cpus left on it */
 165                 new_rate = find_cluster_maxfreq(old_cluster);
 166                 new_rate = ACTUAL_FREQ(old_cluster, new_rate);
 167
 168                 if (new_rate &&
 169                     clk_set_rate(clk[old_cluster], new_rate * 1000)) {
 170                         pr_err("%s: clk_set_rate failed: %d, old cluster: %d\n",
 171                                __func__, ret, old_cluster);
 172                 }
 173                 mutex_unlock(&cluster_lock[old_cluster]);
 174         }
 175
 176         return 0;
 177 }
 178
 179 /* Set clock frequency */
 180 static int ve_spc_cpufreq_set_target(struct cpufreq_policy *policy,
 181                                      unsigned int index)
 182 {
 183         u32 cpu = policy->cpu, cur_cluster, new_cluster, actual_cluster;
 184         unsigned int freqs_new;
 185         int ret;
 186
 187         cur_cluster = cpu_to_cluster(cpu);
 188         new_cluster = actual_cluster = per_cpu(physical_cluster, cpu);
 189
 190         freqs_new = freq_table[cur_cluster][index].frequency;
 191
 192         if (is_bL_switching_enabled()) {
 193                 if (actual_cluster == A15_CLUSTER && freqs_new < clk_big_min)
 194                         new_cluster = A7_CLUSTER;
 195                 else if (actual_cluster == A7_CLUSTER &&
 196                          freqs_new > clk_little_max)
 197                         new_cluster = A15_CLUSTER;
 198         }
 199
 200         ret = ve_spc_cpufreq_set_rate(cpu, actual_cluster, new_cluster,
 201                                       freqs_new);
 202
 203         if (!ret) {
 204                 arch_set_freq_scale(policy->related_cpus, freqs_new,
 205                                     policy->cpuinfo.max_freq);
 206         }
 207
 208         return ret;
 209 }
 210
 211 static inline u32 get_table_count(struct cpufreq_frequency_table *table)
 212 {
 213         int count;
 214
 215         for (count = 0; table[count].frequency != CPUFREQ_TABLE_END; count++)
 216                 ;
 217
 218         return count;
 219 }
 220
 221 /* get the minimum frequency in the cpufreq_frequency_table */
 222 static inline u32 get_table_min(struct cpufreq_frequency_table *table)
 223 {
 224         struct cpufreq_frequency_table *pos;
 225         u32 min_freq = ~0;
 226
 227         cpufreq_for_each_entry(pos, table)
 228                 if (pos->frequency < min_freq)
 229                         min_freq = pos->frequency;
 230         return min_freq;
 231 }
 232
 233 /* get the maximum frequency in the cpufreq_frequency_table */
 234 static inline u32 get_table_max(struct cpufreq_frequency_table *table)
 235 {
 236         struct cpufreq_frequency_table *pos;
 237         u32 max_freq = 0;
 238
 239         cpufreq_for_each_entry(pos, table)
 240                 if (pos->frequency > max_freq)
 241                         max_freq = pos->frequency;
 242         return max_freq;
 243 }
 244
 245 static bool search_frequency(struct cpufreq_frequency_table *table, int size,
 246                              unsigned int freq)
 247 {
 248         int count;
 249
 250         for (count = 0; count < size; count++) {
 251                 if (table[count].frequency == freq)
 252                         return true;
 253         }
 254
 255         return false;
 256 }
 257
 258 static int merge_cluster_tables(void)
 259 {
 260         int i, j, k = 0, count = 1;
 261         struct cpufreq_frequency_table *table;
 262
 263         for (i = 0; i < MAX_CLUSTERS; i++)
 264                 count += get_table_count(freq_table[i]);
 265
 266         table = kcalloc(count, sizeof(*table), GFP_KERNEL);
 267         if (!table)
 268                 return -ENOMEM;
 269
 270         freq_table[MAX_CLUSTERS] = table;
 271
 272         /* Add in reverse order to get freqs in increasing order */
 273         for (i = MAX_CLUSTERS - 1; i >= 0; i--, count = k) {
 274                 for (j = 0; freq_table[i][j].frequency != CPUFREQ_TABLE_END;
 275                      j++) {
 276                         if (i == A15_CLUSTER &&
 277                             search_frequency(table, count, freq_table[i][j].frequency))
 278                                 continue; /* skip duplicates */
 279                         table[k++].frequency =
 280                                 VIRT_FREQ(i, freq_table[i][j].frequency);
 281                 }
 282         }
 283
 284         table[k].driver_data = k;
 285         table[k].frequency = CPUFREQ_TABLE_END;
 286
 287         return 0;
 288 }
 289
 290 static void _put_cluster_clk_and_freq_table(struct device *cpu_dev,
 291                                             const struct cpumask *cpumask)
 292 {
 293         u32 cluster = raw_cpu_to_cluster(cpu_dev->id);
 294
 295         if (!freq_table[cluster])
 296                 return;
 297
 298         clk_put(clk[cluster]);
 299         dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table[cluster]);
 300 }
 301
 302 static void put_cluster_clk_and_freq_table(struct device *cpu_dev,
 303                                            const struct cpumask *cpumask)
 304 {
 305         u32 cluster = cpu_to_cluster(cpu_dev->id);
 306         int i;
 307
 308         if (atomic_dec_return(&cluster_usage[cluster]))
 309                 return;
 310
 311         if (cluster < MAX_CLUSTERS)
 312                 return _put_cluster_clk_and_freq_table(cpu_dev, cpumask);
 313
 314         for_each_present_cpu(i) {
 315                 struct device *cdev = get_cpu_device(i);
 316
 317                 if (!cdev)
 318                         return;
 319
 320                 _put_cluster_clk_and_freq_table(cdev, cpumask);
 321         }
 322
 323         /* free virtual table */
 324         kfree(freq_table[cluster]);
 325 }
 326
 327 static int _get_cluster_clk_and_freq_table(struct device *cpu_dev,
 328                                            const struct cpumask *cpumask)
 329 {
 330         u32 cluster = raw_cpu_to_cluster(cpu_dev->id);
 331         int ret;
 332
 333         if (freq_table[cluster])
 334                 return 0;
 335
 336         /*
 337          * platform specific SPC code must initialise the opp table
 338          * so just check if the OPP count is non-zero
 339          */
 340         ret = dev_pm_opp_get_opp_count(cpu_dev) <= 0;
 341         if (ret)
 342                 goto out;
 343
 344         ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table[cluster]);
 345         if (ret)
 346                 goto out;
 347
 348         clk[cluster] = clk_get(cpu_dev, NULL);
 349         if (!IS_ERR(clk[cluster]))
 350                 return 0;
 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                                           const struct cpumask *cpumask)
 365 {
 366         u32 cluster = cpu_to_cluster(cpu_dev->id);
 367         int i, ret;
 368
 369         if (atomic_inc_return(&cluster_usage[cluster]) != 1)
 370                 return 0;
 371
 372         if (cluster < MAX_CLUSTERS) {
 373                 ret = _get_cluster_clk_and_freq_table(cpu_dev, cpumask);
 374                 if (ret)
 375                         atomic_dec(&cluster_usage[cluster]);
 376                 return ret;
 377         }
 378
 379         /*
 380          * Get data for all clusters and fill virtual cluster with a merge of
 381          * both
 382          */
 383         for_each_present_cpu(i) {
 384                 struct device *cdev = get_cpu_device(i);
 385
 386                 if (!cdev)
 387                         return -ENODEV;
 388
 389                 ret = _get_cluster_clk_and_freq_table(cdev, cpumask);
 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[A15_CLUSTER]);
 400         clk_little_max = VIRT_FREQ(A7_CLUSTER,
 401                                    get_table_max(freq_table[A7_CLUSTER]));
 402
 403         return 0;
 404
 405 put_clusters:
 406         for_each_present_cpu(i) {
 407                 struct device *cdev = get_cpu_device(i);
 408
 409                 if (!cdev)
 410                         return -ENODEV;
 411
 412                 _put_cluster_clk_and_freq_table(cdev, cpumask);
 413         }
 414
 415         atomic_dec(&cluster_usage[cluster]);
 416
 417         return ret;
 418 }
 419
 420 /* Per-CPU initialization */
 421 static int ve_spc_cpufreq_init(struct cpufreq_policy *policy)
 422 {
 423         u32 cur_cluster = cpu_to_cluster(policy->cpu);
 424         struct device *cpu_dev;
 425         int ret;
 426
 427         cpu_dev = get_cpu_device(policy->cpu);
 428         if (!cpu_dev) {
 429                 pr_err("%s: failed to get cpu%d device\n", __func__,
 430                        policy->cpu);
 431                 return -ENODEV;
 432         }
 433
 434         if (cur_cluster < MAX_CLUSTERS) {
 435                 int cpu;
 436
 437                 dev_pm_opp_get_sharing_cpus(cpu_dev, policy->cpus);
 438
 439                 for_each_cpu(cpu, policy->cpus)
 440                         per_cpu(physical_cluster, cpu) = cur_cluster;
 441         } else {
 442                 /* Assumption: during init, we are always running on A15 */
 443                 per_cpu(physical_cluster, policy->cpu) = A15_CLUSTER;
 444         }
 445
 446         ret = get_cluster_clk_and_freq_table(cpu_dev, policy->cpus);
 447         if (ret)
 448                 return ret;
 449
 450         policy->freq_table = freq_table[cur_cluster];
 451         policy->cpuinfo.transition_latency = 1000000; /* 1 ms */
 452
 453         dev_pm_opp_of_register_em(cpu_dev, policy->cpus);
 454
 455         if (is_bL_switching_enabled())
 456                 per_cpu(cpu_last_req_freq, policy->cpu) =
 457                                                 clk_get_cpu_rate(policy->cpu);
 458
 459         dev_info(cpu_dev, "%s: CPU %d initialized\n", __func__, policy->cpu);
 460         return 0;
 461 }
 462
 463 static int ve_spc_cpufreq_exit(struct cpufreq_policy *policy)
 464 {
 465         struct device *cpu_dev;
 466         int cur_cluster = cpu_to_cluster(policy->cpu);
 467
 468         if (cur_cluster < MAX_CLUSTERS) {
 469                 cpufreq_cooling_unregister(cdev[cur_cluster]);
 470                 cdev[cur_cluster] = NULL;
 471         }
 472
 473         cpu_dev = get_cpu_device(policy->cpu);
 474         if (!cpu_dev) {
 475                 pr_err("%s: failed to get cpu%d device\n", __func__,
 476                        policy->cpu);
 477                 return -ENODEV;
 478         }
 479
 480         put_cluster_clk_and_freq_table(cpu_dev, policy->related_cpus);
 481         return 0;
 482 }
 483
 484 static void ve_spc_cpufreq_ready(struct cpufreq_policy *policy)
 485 {
 486         int cur_cluster = cpu_to_cluster(policy->cpu);
 487
 488         /* Do not register a cpu_cooling device if we are in IKS mode */
 489         if (cur_cluster >= MAX_CLUSTERS)
 490                 return;
 491
 492         cdev[cur_cluster] = of_cpufreq_cooling_register(policy);
 493 }
 494
 495 static struct cpufreq_driver ve_spc_cpufreq_driver = {
 496         .name                   = "vexpress-spc",
 497         .flags                  = CPUFREQ_STICKY |
 498                                         CPUFREQ_HAVE_GOVERNOR_PER_POLICY |
 499                                         CPUFREQ_NEED_INITIAL_FREQ_CHECK,
 500         .verify                 = cpufreq_generic_frequency_table_verify,
 501         .target_index           = ve_spc_cpufreq_set_target,
 502         .get                    = ve_spc_cpufreq_get_rate,
 503         .init                   = ve_spc_cpufreq_init,
 504         .exit                   = ve_spc_cpufreq_exit,
 505         .ready                  = ve_spc_cpufreq_ready,
 506         .attr                   = cpufreq_generic_attr,
 507 };
 508
 509 #ifdef CONFIG_BL_SWITCHER
 510 static int bL_cpufreq_switcher_notifier(struct notifier_block *nfb,
 511                                         unsigned long action, void *_arg)
 512 {
 513         pr_debug("%s: action: %ld\n", __func__, action);
 514
 515         switch (action) {
 516         case BL_NOTIFY_PRE_ENABLE:
 517         case BL_NOTIFY_PRE_DISABLE:
 518                 cpufreq_unregister_driver(&ve_spc_cpufreq_driver);
 519                 break;
 520
 521         case BL_NOTIFY_POST_ENABLE:
 522                 set_switching_enabled(true);
 523                 cpufreq_register_driver(&ve_spc_cpufreq_driver);
 524                 break;
 525
 526         case BL_NOTIFY_POST_DISABLE:
 527                 set_switching_enabled(false);
 528                 cpufreq_register_driver(&ve_spc_cpufreq_driver);
 529                 break;
 530
 531         default:
 532                 return NOTIFY_DONE;
 533         }
 534
 535         return NOTIFY_OK;
 536 }
 537
 538 static struct notifier_block bL_switcher_notifier = {
 539         .notifier_call = bL_cpufreq_switcher_notifier,
 540 };
 541
 542 static int __bLs_register_notifier(void)
 543 {
 544         return bL_switcher_register_notifier(&bL_switcher_notifier);
 545 }
 546
 547 static int __bLs_unregister_notifier(void)
 548 {
 549         return bL_switcher_unregister_notifier(&bL_switcher_notifier);
 550 }
 551 #else
 552 static int __bLs_register_notifier(void) { return 0; }
 553 static int __bLs_unregister_notifier(void) { return 0; }
 554 #endif
 555
 556 static int ve_spc_cpufreq_probe(struct platform_device *pdev)
 557 {
 558         int ret, i;
 559
 560         set_switching_enabled(bL_switcher_get_enabled());
 561
 562         for (i = 0; i < MAX_CLUSTERS; i++)
 563                 mutex_init(&cluster_lock[i]);
 564
 565         ret = cpufreq_register_driver(&ve_spc_cpufreq_driver);
 566         if (ret) {
 567                 pr_info("%s: Failed registering platform driver: %s, err: %d\n",
 568                         __func__, ve_spc_cpufreq_driver.name, ret);
 569         } else {
 570                 ret = __bLs_register_notifier();
 571                 if (ret)
 572                         cpufreq_unregister_driver(&ve_spc_cpufreq_driver);
 573                 else
 574                         pr_info("%s: Registered platform driver: %s\n",
 575                                 __func__, ve_spc_cpufreq_driver.name);
 576         }
 577
 578         bL_switcher_put_enabled();
 579         return ret;
 580 }
 581
 582 static int ve_spc_cpufreq_remove(struct platform_device *pdev)
 583 {
 584         bL_switcher_get_enabled();
 585         __bLs_unregister_notifier();
 586         cpufreq_unregister_driver(&ve_spc_cpufreq_driver);
 587         bL_switcher_put_enabled();
 588         pr_info("%s: Un-registered platform driver: %s\n", __func__,
 589                 ve_spc_cpufreq_driver.name);
 590         return 0;
 591 }
 592
 593 static struct platform_driver ve_spc_cpufreq_platdrv = {
 594         .driver = {
 595                 .name   = "vexpress-spc-cpufreq",
 596         },
 597         .probe          = ve_spc_cpufreq_probe,
 598         .remove         = ve_spc_cpufreq_remove,
 599 };
 600 module_platform_driver(ve_spc_cpufreq_platdrv);
 601
 602 MODULE_AUTHOR("Viresh Kumar <viresh.kumar@linaro.org>");
 603 MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>");
 604 MODULE_DESCRIPTION("Vexpress SPC ARM big LITTLE cpufreq driver");
 605 MODULE_LICENSE("GPL v2");