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