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/device.h>
  19 #include <linux/module.h>
  20 #include <linux/mutex.h>
  21 #include <linux/of_platform.h>
  22 #include <linux/platform_device.h>
  23 #include <linux/pm_opp.h>
  24 #include <linux/slab.h>
  25 #include <linux/topology.h>
  26 #include <linux/types.h>
  27
  28 /* Currently we support only two clusters */
  29 #define A15_CLUSTER     0
  30 #define A7_CLUSTER      1
  31 #define MAX_CLUSTERS    2
  32
  33 #ifdef CONFIG_BL_SWITCHER
  34 #include <asm/bL_switcher.h>
  35 static bool bL_switching_enabled;
  36 #define is_bL_switching_enabled()       bL_switching_enabled
  37 #define set_switching_enabled(x)        (bL_switching_enabled = (x))
  38 #else
  39 #define is_bL_switching_enabled()       false
  40 #define set_switching_enabled(x)        do { } while (0)
  41 #define bL_switch_request(...)          do { } while (0)
  42 #define bL_switcher_put_enabled()       do { } while (0)
  43 #define bL_switcher_get_enabled()       do { } while (0)
  44 #endif
  45
  46 #define ACTUAL_FREQ(cluster, freq)  ((cluster == A7_CLUSTER) ? freq << 1 : freq)
  47 #define VIRT_FREQ(cluster, freq)    ((cluster == A7_CLUSTER) ? freq >> 1 : freq)
  48
  49 static struct clk *clk[MAX_CLUSTERS];
  50 static struct cpufreq_frequency_table *freq_table[MAX_CLUSTERS + 1];
  51 static atomic_t cluster_usage[MAX_CLUSTERS + 1];
  52
  53 static unsigned int clk_big_min;        /* (Big) clock frequencies */
  54 static unsigned int clk_little_max;     /* Maximum clock frequency (Little) */
  55
  56 static DEFINE_PER_CPU(unsigned int, physical_cluster);
  57 static DEFINE_PER_CPU(unsigned int, cpu_last_req_freq);
  58
  59 static struct mutex cluster_lock[MAX_CLUSTERS];
  60
  61 static inline int raw_cpu_to_cluster(int cpu)
  62 {
  63         return topology_physical_package_id(cpu);
  64 }
  65
  66 static inline int cpu_to_cluster(int cpu)
  67 {
  68         return is_bL_switching_enabled() ?
  69                 MAX_CLUSTERS : raw_cpu_to_cluster(cpu);
  70 }
  71
  72 static unsigned int find_cluster_maxfreq(int cluster)
  73 {
  74         int j;
  75         u32 max_freq = 0, cpu_freq;
  76
  77         for_each_online_cpu(j) {
  78                 cpu_freq = per_cpu(cpu_last_req_freq, j);
  79
  80                 if (cluster == per_cpu(physical_cluster, j) &&
  81                     max_freq < cpu_freq)
  82                         max_freq = cpu_freq;
  83         }
  84
  85         return max_freq;
  86 }
  87
  88 static unsigned int clk_get_cpu_rate(unsigned int cpu)
  89 {
  90         u32 cur_cluster = per_cpu(physical_cluster, cpu);
  91         u32 rate = clk_get_rate(clk[cur_cluster]) / 1000;
  92
  93         /* For switcher we use virtual A7 clock rates */
  94         if (is_bL_switching_enabled())
  95                 rate = VIRT_FREQ(cur_cluster, rate);
  96
  97         return rate;
  98 }
  99
 100 static unsigned int ve_spc_cpufreq_get_rate(unsigned int cpu)
 101 {
 102         if (is_bL_switching_enabled())
 103                 return per_cpu(cpu_last_req_freq, cpu);
 104         else
 105                 return clk_get_cpu_rate(cpu);
 106 }
 107
 108 static unsigned int
 109 ve_spc_cpufreq_set_rate(u32 cpu, u32 old_cluster, u32 new_cluster, u32 rate)
 110 {
 111         u32 new_rate, prev_rate;
 112         int ret;
 113         bool bLs = is_bL_switching_enabled();
 114
 115         mutex_lock(&cluster_lock[new_cluster]);
 116
 117         if (bLs) {
 118                 prev_rate = per_cpu(cpu_last_req_freq, cpu);
 119                 per_cpu(cpu_last_req_freq, cpu) = rate;
 120                 per_cpu(physical_cluster, cpu) = new_cluster;
 121
 122                 new_rate = find_cluster_maxfreq(new_cluster);
 123                 new_rate = ACTUAL_FREQ(new_cluster, new_rate);
 124         } else {
 125                 new_rate = rate;
 126         }
 127
 128         ret = clk_set_rate(clk[new_cluster], new_rate * 1000);
 129         if (!ret) {
 130                 /*
 131                  * FIXME: clk_set_rate hasn't returned an error here however it
 132                  * may be that clk_change_rate failed due to hardware or
 133                  * firmware issues and wasn't able to report that due to the
 134                  * current design of the clk core layer. To work around this
 135                  * problem we will read back the clock rate and check it is
 136                  * correct. This needs to be removed once clk core is fixed.
 137                  */
 138                 if (clk_get_rate(clk[new_cluster]) != new_rate * 1000)
 139                         ret = -EIO;
 140         }
 141
 142         if (WARN_ON(ret)) {
 143                 if (bLs) {
 144                         per_cpu(cpu_last_req_freq, cpu) = prev_rate;
 145                         per_cpu(physical_cluster, cpu) = old_cluster;
 146                 }
 147
 148                 mutex_unlock(&cluster_lock[new_cluster]);
 149
 150                 return ret;
 151         }
 152
 153         mutex_unlock(&cluster_lock[new_cluster]);
 154
 155         /* Recalc freq for old cluster when switching clusters */
 156         if (old_cluster != new_cluster) {
 157                 /* Switch cluster */
 158                 bL_switch_request(cpu, new_cluster);
 159
 160                 mutex_lock(&cluster_lock[old_cluster]);
 161
 162                 /* Set freq of old cluster if there are cpus left on it */
 163                 new_rate = find_cluster_maxfreq(old_cluster);
 164                 new_rate = ACTUAL_FREQ(old_cluster, new_rate);
 165
 166                 if (new_rate &&
 167                     clk_set_rate(clk[old_cluster], new_rate * 1000)) {
 168                         pr_err("%s: clk_set_rate failed: %d, old cluster: %d\n",
 169                                __func__, ret, old_cluster);
 170                 }
 171                 mutex_unlock(&cluster_lock[old_cluster]);
 172         }
 173
 174         return 0;
 175 }
 176
 177 /* Set clock frequency */
 178 static int ve_spc_cpufreq_set_target(struct cpufreq_policy *policy,
 179                                      unsigned int index)
 180 {
 181         u32 cpu = policy->cpu, cur_cluster, new_cluster, actual_cluster;
 182         unsigned int freqs_new;
 183
 184         cur_cluster = cpu_to_cluster(cpu);
 185         new_cluster = actual_cluster = per_cpu(physical_cluster, cpu);
 186
 187         freqs_new = freq_table[cur_cluster][index].frequency;
 188
 189         if (is_bL_switching_enabled()) {
 190                 if (actual_cluster == A15_CLUSTER && freqs_new < clk_big_min)
 191                         new_cluster = A7_CLUSTER;
 192                 else if (actual_cluster == A7_CLUSTER &&
 193                          freqs_new > clk_little_max)
 194                         new_cluster = A15_CLUSTER;
 195         }
 196
 197         return ve_spc_cpufreq_set_rate(cpu, actual_cluster, new_cluster,
 198                                        freqs_new);
 199 }
 200
 201 static inline u32 get_table_count(struct cpufreq_frequency_table *table)
 202 {
 203         int count;
 204
 205         for (count = 0; table[count].frequency != CPUFREQ_TABLE_END; count++)
 206                 ;
 207
 208         return count;
 209 }
 210
 211 /* get the minimum frequency in the cpufreq_frequency_table */
 212 static inline u32 get_table_min(struct cpufreq_frequency_table *table)
 213 {
 214         struct cpufreq_frequency_table *pos;
 215         u32 min_freq = ~0;
 216
 217         cpufreq_for_each_entry(pos, table)
 218                 if (pos->frequency < min_freq)
 219                         min_freq = pos->frequency;
 220         return min_freq;
 221 }
 222
 223 /* get the maximum frequency in the cpufreq_frequency_table */
 224 static inline u32 get_table_max(struct cpufreq_frequency_table *table)
 225 {
 226         struct cpufreq_frequency_table *pos;
 227         u32 max_freq = 0;
 228
 229         cpufreq_for_each_entry(pos, table)
 230                 if (pos->frequency > max_freq)
 231                         max_freq = pos->frequency;
 232         return max_freq;
 233 }
 234
 235 static bool search_frequency(struct cpufreq_frequency_table *table, int size,
 236                              unsigned int freq)
 237 {
 238         int count;
 239
 240         for (count = 0; count < size; count++) {
 241                 if (table[count].frequency == freq)
 242                         return true;
 243         }
 244
 245         return false;
 246 }
 247
 248 static int merge_cluster_tables(void)
 249 {
 250         int i, j, k = 0, count = 1;
 251         struct cpufreq_frequency_table *table;
 252
 253         for (i = 0; i < MAX_CLUSTERS; i++)
 254                 count += get_table_count(freq_table[i]);
 255
 256         table = kcalloc(count, sizeof(*table), GFP_KERNEL);
 257         if (!table)
 258                 return -ENOMEM;
 259
 260         freq_table[MAX_CLUSTERS] = table;
 261
 262         /* Add in reverse order to get freqs in increasing order */
 263         for (i = MAX_CLUSTERS - 1; i >= 0; i--, count = k) {
 264                 for (j = 0; freq_table[i][j].frequency != CPUFREQ_TABLE_END;
 265                      j++) {
 266                         if (i == A15_CLUSTER &&
 267                             search_frequency(table, count, freq_table[i][j].frequency))
 268                                 continue; /* skip duplicates */
 269                         table[k++].frequency =
 270                                 VIRT_FREQ(i, freq_table[i][j].frequency);
 271                 }
 272         }
 273
 274         table[k].driver_data = k;
 275         table[k].frequency = CPUFREQ_TABLE_END;
 276
 277         return 0;
 278 }
 279
 280 static void _put_cluster_clk_and_freq_table(struct device *cpu_dev,
 281                                             const struct cpumask *cpumask)
 282 {
 283         u32 cluster = raw_cpu_to_cluster(cpu_dev->id);
 284
 285         if (!freq_table[cluster])
 286                 return;
 287
 288         clk_put(clk[cluster]);
 289         dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table[cluster]);
 290 }
 291
 292 static void put_cluster_clk_and_freq_table(struct device *cpu_dev,
 293                                            const struct cpumask *cpumask)
 294 {
 295         u32 cluster = cpu_to_cluster(cpu_dev->id);
 296         int i;
 297
 298         if (atomic_dec_return(&cluster_usage[cluster]))
 299                 return;
 300
 301         if (cluster < MAX_CLUSTERS)
 302                 return _put_cluster_clk_and_freq_table(cpu_dev, cpumask);
 303
 304         for_each_present_cpu(i) {
 305                 struct device *cdev = get_cpu_device(i);
 306
 307                 if (!cdev)
 308                         return;
 309
 310                 _put_cluster_clk_and_freq_table(cdev, cpumask);
 311         }
 312
 313         /* free virtual table */
 314         kfree(freq_table[cluster]);
 315 }
 316
 317 static int _get_cluster_clk_and_freq_table(struct device *cpu_dev,
 318                                            const struct cpumask *cpumask)
 319 {
 320         u32 cluster = raw_cpu_to_cluster(cpu_dev->id);
 321         int ret;
 322
 323         if (freq_table[cluster])
 324                 return 0;
 325
 326         /*
 327          * platform specific SPC code must initialise the opp table
 328          * so just check if the OPP count is non-zero
 329          */
 330         ret = dev_pm_opp_get_opp_count(cpu_dev) <= 0;
 331         if (ret)
 332                 goto out;
 333
 334         ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table[cluster]);
 335         if (ret)
 336                 goto out;
 337
 338         clk[cluster] = clk_get(cpu_dev, NULL);
 339         if (!IS_ERR(clk[cluster]))
 340                 return 0;
 341
 342         dev_err(cpu_dev, "%s: Failed to get clk for cpu: %d, cluster: %d\n",
 343                 __func__, cpu_dev->id, cluster);
 344         ret = PTR_ERR(clk[cluster]);
 345         dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table[cluster]);
 346
 347 out:
 348         dev_err(cpu_dev, "%s: Failed to get data for cluster: %d\n", __func__,
 349                 cluster);
 350         return ret;
 351 }
 352
 353 static int get_cluster_clk_and_freq_table(struct device *cpu_dev,
 354                                           const struct cpumask *cpumask)
 355 {
 356         u32 cluster = cpu_to_cluster(cpu_dev->id);
 357         int i, ret;
 358
 359         if (atomic_inc_return(&cluster_usage[cluster]) != 1)
 360                 return 0;
 361
 362         if (cluster < MAX_CLUSTERS) {
 363                 ret = _get_cluster_clk_and_freq_table(cpu_dev, cpumask);
 364                 if (ret)
 365                         atomic_dec(&cluster_usage[cluster]);
 366                 return ret;
 367         }
 368
 369         /*
 370          * Get data for all clusters and fill virtual cluster with a merge of
 371          * both
 372          */
 373         for_each_present_cpu(i) {
 374                 struct device *cdev = get_cpu_device(i);
 375
 376                 if (!cdev)
 377                         return -ENODEV;
 378
 379                 ret = _get_cluster_clk_and_freq_table(cdev, cpumask);
 380                 if (ret)
 381                         goto put_clusters;
 382         }
 383
 384         ret = merge_cluster_tables();
 385         if (ret)
 386                 goto put_clusters;
 387
 388         /* Assuming 2 cluster, set clk_big_min and clk_little_max */
 389         clk_big_min = get_table_min(freq_table[A15_CLUSTER]);
 390         clk_little_max = VIRT_FREQ(A7_CLUSTER,
 391                                    get_table_max(freq_table[A7_CLUSTER]));
 392
 393         return 0;
 394
 395 put_clusters:
 396         for_each_present_cpu(i) {
 397                 struct device *cdev = get_cpu_device(i);
 398
 399                 if (!cdev)
 400                         return -ENODEV;
 401
 402                 _put_cluster_clk_and_freq_table(cdev, cpumask);
 403         }
 404
 405         atomic_dec(&cluster_usage[cluster]);
 406
 407         return ret;
 408 }
 409
 410 /* Per-CPU initialization */
 411 static int ve_spc_cpufreq_init(struct cpufreq_policy *policy)
 412 {
 413         u32 cur_cluster = cpu_to_cluster(policy->cpu);
 414         struct device *cpu_dev;
 415         int ret;
 416
 417         cpu_dev = get_cpu_device(policy->cpu);
 418         if (!cpu_dev) {
 419                 pr_err("%s: failed to get cpu%d device\n", __func__,
 420                        policy->cpu);
 421                 return -ENODEV;
 422         }
 423
 424         if (cur_cluster < MAX_CLUSTERS) {
 425                 int cpu;
 426
 427                 dev_pm_opp_get_sharing_cpus(cpu_dev, policy->cpus);
 428
 429                 for_each_cpu(cpu, policy->cpus)
 430                         per_cpu(physical_cluster, cpu) = cur_cluster;
 431         } else {
 432                 /* Assumption: during init, we are always running on A15 */
 433                 per_cpu(physical_cluster, policy->cpu) = A15_CLUSTER;
 434         }
 435
 436         ret = get_cluster_clk_and_freq_table(cpu_dev, policy->cpus);
 437         if (ret)
 438                 return ret;
 439
 440         policy->freq_table = freq_table[cur_cluster];
 441         policy->cpuinfo.transition_latency = 1000000; /* 1 ms */
 442
 443         if (is_bL_switching_enabled())
 444                 per_cpu(cpu_last_req_freq, policy->cpu) =
 445                                                 clk_get_cpu_rate(policy->cpu);
 446
 447         dev_info(cpu_dev, "%s: CPU %d initialized\n", __func__, policy->cpu);
 448         return 0;
 449 }
 450
 451 static int ve_spc_cpufreq_exit(struct cpufreq_policy *policy)
 452 {
 453         struct device *cpu_dev;
 454         int cur_cluster = cpu_to_cluster(policy->cpu);
 455
 456         cpu_dev = get_cpu_device(policy->cpu);
 457         if (!cpu_dev) {
 458                 pr_err("%s: failed to get cpu%d device\n", __func__,
 459                        policy->cpu);
 460                 return -ENODEV;
 461         }
 462
 463         put_cluster_clk_and_freq_table(cpu_dev, policy->related_cpus);
 464         return 0;
 465 }
 466
 467 static struct cpufreq_driver ve_spc_cpufreq_driver = {
 468         .name                   = "vexpress-spc",
 469         .flags                  = CPUFREQ_HAVE_GOVERNOR_PER_POLICY |
 470                                         CPUFREQ_NEED_INITIAL_FREQ_CHECK,
 471         .verify                 = cpufreq_generic_frequency_table_verify,
 472         .target_index           = ve_spc_cpufreq_set_target,
 473         .get                    = ve_spc_cpufreq_get_rate,
 474         .init                   = ve_spc_cpufreq_init,
 475         .exit                   = ve_spc_cpufreq_exit,
 476         .register_em            = cpufreq_register_em_with_opp,
 477         .attr                   = cpufreq_generic_attr,
 478 };
 479
 480 #ifdef CONFIG_BL_SWITCHER
 481 static int bL_cpufreq_switcher_notifier(struct notifier_block *nfb,
 482                                         unsigned long action, void *_arg)
 483 {
 484         pr_debug("%s: action: %ld\n", __func__, action);
 485
 486         switch (action) {
 487         case BL_NOTIFY_PRE_ENABLE:
 488         case BL_NOTIFY_PRE_DISABLE:
 489                 cpufreq_unregister_driver(&ve_spc_cpufreq_driver);
 490                 break;
 491
 492         case BL_NOTIFY_POST_ENABLE:
 493                 set_switching_enabled(true);
 494                 cpufreq_register_driver(&ve_spc_cpufreq_driver);
 495                 break;
 496
 497         case BL_NOTIFY_POST_DISABLE:
 498                 set_switching_enabled(false);
 499                 cpufreq_register_driver(&ve_spc_cpufreq_driver);
 500                 break;
 501
 502         default:
 503                 return NOTIFY_DONE;
 504         }
 505
 506         return NOTIFY_OK;
 507 }
 508
 509 static struct notifier_block bL_switcher_notifier = {
 510         .notifier_call = bL_cpufreq_switcher_notifier,
 511 };
 512
 513 static int __bLs_register_notifier(void)
 514 {
 515         return bL_switcher_register_notifier(&bL_switcher_notifier);
 516 }
 517
 518 static int __bLs_unregister_notifier(void)
 519 {
 520         return bL_switcher_unregister_notifier(&bL_switcher_notifier);
 521 }
 522 #else
 523 static int __bLs_register_notifier(void) { return 0; }
 524 static int __bLs_unregister_notifier(void) { return 0; }
 525 #endif
 526
 527 static int ve_spc_cpufreq_probe(struct platform_device *pdev)
 528 {
 529         int ret, i;
 530
 531         set_switching_enabled(bL_switcher_get_enabled());
 532
 533         for (i = 0; i < MAX_CLUSTERS; i++)
 534                 mutex_init(&cluster_lock[i]);
 535
 536         if (!is_bL_switching_enabled())
 537                 ve_spc_cpufreq_driver.flags |= CPUFREQ_IS_COOLING_DEV;
 538
 539         ret = cpufreq_register_driver(&ve_spc_cpufreq_driver);
 540         if (ret) {
 541                 pr_info("%s: Failed registering platform driver: %s, err: %d\n",
 542                         __func__, ve_spc_cpufreq_driver.name, ret);
 543         } else {
 544                 ret = __bLs_register_notifier();
 545                 if (ret)
 546                         cpufreq_unregister_driver(&ve_spc_cpufreq_driver);
 547                 else
 548                         pr_info("%s: Registered platform driver: %s\n",
 549                                 __func__, ve_spc_cpufreq_driver.name);
 550         }
 551
 552         bL_switcher_put_enabled();
 553         return ret;
 554 }
 555
 556 static int ve_spc_cpufreq_remove(struct platform_device *pdev)
 557 {
 558         bL_switcher_get_enabled();
 559         __bLs_unregister_notifier();
 560         cpufreq_unregister_driver(&ve_spc_cpufreq_driver);
 561         bL_switcher_put_enabled();
 562         pr_info("%s: Un-registered platform driver: %s\n", __func__,
 563                 ve_spc_cpufreq_driver.name);
 564         return 0;
 565 }
 566
 567 static struct platform_driver ve_spc_cpufreq_platdrv = {
 568         .driver = {
 569                 .name   = "vexpress-spc-cpufreq",
 570         },
 571         .probe          = ve_spc_cpufreq_probe,
 572         .remove         = ve_spc_cpufreq_remove,
 573 };
 574 module_platform_driver(ve_spc_cpufreq_platdrv);
 575
 576 MODULE_ALIAS("platform:vexpress-spc-cpufreq");
 577 MODULE_AUTHOR("Viresh Kumar <viresh.kumar@linaro.org>");
 578 MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>");
 579 MODULE_DESCRIPTION("Vexpress SPC ARM big LITTLE cpufreq driver");
 580 MODULE_LICENSE("GPL v2");