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
 186         cur_cluster = cpu_to_cluster(cpu);
 187         new_cluster = actual_cluster = per_cpu(physical_cluster, cpu);
 188
 189         freqs_new = freq_table[cur_cluster][index].frequency;
 190
 191         if (is_bL_switching_enabled()) {
 192                 if (actual_cluster == A15_CLUSTER && freqs_new < clk_big_min)
 193                         new_cluster = A7_CLUSTER;
 194                 else if (actual_cluster == A7_CLUSTER &&
 195                          freqs_new > clk_little_max)
 196                         new_cluster = A15_CLUSTER;
 197         }
 198
 199         return ve_spc_cpufreq_set_rate(cpu, actual_cluster, new_cluster,
 200                                        freqs_new);
 201 }
 202
 203 static inline u32 get_table_count(struct cpufreq_frequency_table *table)
 204 {
 205         int count;
 206
 207         for (count = 0; table[count].frequency != CPUFREQ_TABLE_END; count++)
 208                 ;
 209
 210         return count;
 211 }
 212
 213 /* get the minimum frequency in the cpufreq_frequency_table */
 214 static inline u32 get_table_min(struct cpufreq_frequency_table *table)
 215 {
 216         struct cpufreq_frequency_table *pos;
 217         u32 min_freq = ~0;
 218
 219         cpufreq_for_each_entry(pos, table)
 220                 if (pos->frequency < min_freq)
 221                         min_freq = pos->frequency;
 222         return min_freq;
 223 }
 224
 225 /* get the maximum frequency in the cpufreq_frequency_table */
 226 static inline u32 get_table_max(struct cpufreq_frequency_table *table)
 227 {
 228         struct cpufreq_frequency_table *pos;
 229         u32 max_freq = 0;
 230
 231         cpufreq_for_each_entry(pos, table)
 232                 if (pos->frequency > max_freq)
 233                         max_freq = pos->frequency;
 234         return max_freq;
 235 }
 236
 237 static bool search_frequency(struct cpufreq_frequency_table *table, int size,
 238                              unsigned int freq)
 239 {
 240         int count;
 241
 242         for (count = 0; count < size; count++) {
 243                 if (table[count].frequency == freq)
 244                         return true;
 245         }
 246
 247         return false;
 248 }
 249
 250 static int merge_cluster_tables(void)
 251 {
 252         int i, j, k = 0, count = 1;
 253         struct cpufreq_frequency_table *table;
 254
 255         for (i = 0; i < MAX_CLUSTERS; i++)
 256                 count += get_table_count(freq_table[i]);
 257
 258         table = kcalloc(count, sizeof(*table), GFP_KERNEL);
 259         if (!table)
 260                 return -ENOMEM;
 261
 262         freq_table[MAX_CLUSTERS] = table;
 263
 264         /* Add in reverse order to get freqs in increasing order */
 265         for (i = MAX_CLUSTERS - 1; i >= 0; i--, count = k) {
 266                 for (j = 0; freq_table[i][j].frequency != CPUFREQ_TABLE_END;
 267                      j++) {
 268                         if (i == A15_CLUSTER &&
 269                             search_frequency(table, count, freq_table[i][j].frequency))
 270                                 continue; /* skip duplicates */
 271                         table[k++].frequency =
 272                                 VIRT_FREQ(i, freq_table[i][j].frequency);
 273                 }
 274         }
 275
 276         table[k].driver_data = k;
 277         table[k].frequency = CPUFREQ_TABLE_END;
 278
 279         return 0;
 280 }
 281
 282 static void _put_cluster_clk_and_freq_table(struct device *cpu_dev,
 283                                             const struct cpumask *cpumask)
 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 }
 293
 294 static void put_cluster_clk_and_freq_table(struct device *cpu_dev,
 295                                            const struct cpumask *cpumask)
 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, cpumask);
 305
 306         for_each_present_cpu(i) {
 307                 struct device *cdev = get_cpu_device(i);
 308
 309                 if (!cdev)
 310                         return;
 311
 312                 _put_cluster_clk_and_freq_table(cdev, cpumask);
 313         }
 314
 315         /* free virtual table */
 316         kfree(freq_table[cluster]);
 317 }
 318
 319 static int _get_cluster_clk_and_freq_table(struct device *cpu_dev,
 320                                            const struct cpumask *cpumask)
 321 {
 322         u32 cluster = raw_cpu_to_cluster(cpu_dev->id);
 323         int ret;
 324
 325         if (freq_table[cluster])
 326                 return 0;
 327
 328         /*
 329          * platform specific SPC code must initialise the opp table
 330          * so just check if the OPP count is non-zero
 331          */
 332         ret = dev_pm_opp_get_opp_count(cpu_dev) <= 0;
 333         if (ret)
 334                 goto out;
 335
 336         ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table[cluster]);
 337         if (ret)
 338                 goto out;
 339
 340         clk[cluster] = clk_get(cpu_dev, NULL);
 341         if (!IS_ERR(clk[cluster]))
 342                 return 0;
 343
 344         dev_err(cpu_dev, "%s: Failed to get clk for cpu: %d, cluster: %d\n",
 345                 __func__, cpu_dev->id, cluster);
 346         ret = PTR_ERR(clk[cluster]);
 347         dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table[cluster]);
 348
 349 out:
 350         dev_err(cpu_dev, "%s: Failed to get data for cluster: %d\n", __func__,
 351                 cluster);
 352         return ret;
 353 }
 354
 355 static int get_cluster_clk_and_freq_table(struct device *cpu_dev,
 356                                           const struct cpumask *cpumask)
 357 {
 358         u32 cluster = cpu_to_cluster(cpu_dev->id);
 359         int i, ret;
 360
 361         if (atomic_inc_return(&cluster_usage[cluster]) != 1)
 362                 return 0;
 363
 364         if (cluster < MAX_CLUSTERS) {
 365                 ret = _get_cluster_clk_and_freq_table(cpu_dev, cpumask);
 366                 if (ret)
 367                         atomic_dec(&cluster_usage[cluster]);
 368                 return ret;
 369         }
 370
 371         /*
 372          * Get data for all clusters and fill virtual cluster with a merge of
 373          * both
 374          */
 375         for_each_present_cpu(i) {
 376                 struct device *cdev = get_cpu_device(i);
 377
 378                 if (!cdev)
 379                         return -ENODEV;
 380
 381                 ret = _get_cluster_clk_and_freq_table(cdev, cpumask);
 382                 if (ret)
 383                         goto put_clusters;
 384         }
 385
 386         ret = merge_cluster_tables();
 387         if (ret)
 388                 goto put_clusters;
 389
 390         /* Assuming 2 cluster, set clk_big_min and clk_little_max */
 391         clk_big_min = get_table_min(freq_table[A15_CLUSTER]);
 392         clk_little_max = VIRT_FREQ(A7_CLUSTER,
 393                                    get_table_max(freq_table[A7_CLUSTER]));
 394
 395         return 0;
 396
 397 put_clusters:
 398         for_each_present_cpu(i) {
 399                 struct device *cdev = get_cpu_device(i);
 400
 401                 if (!cdev)
 402                         return -ENODEV;
 403
 404                 _put_cluster_clk_and_freq_table(cdev, cpumask);
 405         }
 406
 407         atomic_dec(&cluster_usage[cluster]);
 408
 409         return ret;
 410 }
 411
 412 /* Per-CPU initialization */
 413 static int ve_spc_cpufreq_init(struct cpufreq_policy *policy)
 414 {
 415         u32 cur_cluster = cpu_to_cluster(policy->cpu);
 416         struct device *cpu_dev;
 417         int ret;
 418
 419         cpu_dev = get_cpu_device(policy->cpu);
 420         if (!cpu_dev) {
 421                 pr_err("%s: failed to get cpu%d device\n", __func__,
 422                        policy->cpu);
 423                 return -ENODEV;
 424         }
 425
 426         if (cur_cluster < MAX_CLUSTERS) {
 427                 int cpu;
 428
 429                 dev_pm_opp_get_sharing_cpus(cpu_dev, policy->cpus);
 430
 431                 for_each_cpu(cpu, policy->cpus)
 432                         per_cpu(physical_cluster, cpu) = cur_cluster;
 433         } else {
 434                 /* Assumption: during init, we are always running on A15 */
 435                 per_cpu(physical_cluster, policy->cpu) = A15_CLUSTER;
 436         }
 437
 438         ret = get_cluster_clk_and_freq_table(cpu_dev, policy->cpus);
 439         if (ret)
 440                 return ret;
 441
 442         policy->freq_table = freq_table[cur_cluster];
 443         policy->cpuinfo.transition_latency = 1000000; /* 1 ms */
 444
 445         dev_pm_opp_of_register_em(cpu_dev, policy->cpus);
 446
 447         if (is_bL_switching_enabled())
 448                 per_cpu(cpu_last_req_freq, policy->cpu) =
 449                                                 clk_get_cpu_rate(policy->cpu);
 450
 451         dev_info(cpu_dev, "%s: CPU %d initialized\n", __func__, policy->cpu);
 452         return 0;
 453 }
 454
 455 static int ve_spc_cpufreq_exit(struct cpufreq_policy *policy)
 456 {
 457         struct device *cpu_dev;
 458         int cur_cluster = cpu_to_cluster(policy->cpu);
 459
 460         if (cur_cluster < MAX_CLUSTERS) {
 461                 cpufreq_cooling_unregister(cdev[cur_cluster]);
 462                 cdev[cur_cluster] = NULL;
 463         }
 464
 465         cpu_dev = get_cpu_device(policy->cpu);
 466         if (!cpu_dev) {
 467                 pr_err("%s: failed to get cpu%d device\n", __func__,
 468                        policy->cpu);
 469                 return -ENODEV;
 470         }
 471
 472         put_cluster_clk_and_freq_table(cpu_dev, policy->related_cpus);
 473         return 0;
 474 }
 475
 476 static void ve_spc_cpufreq_ready(struct cpufreq_policy *policy)
 477 {
 478         int cur_cluster = cpu_to_cluster(policy->cpu);
 479
 480         /* Do not register a cpu_cooling device if we are in IKS mode */
 481         if (cur_cluster >= MAX_CLUSTERS)
 482                 return;
 483
 484         cdev[cur_cluster] = of_cpufreq_cooling_register(policy);
 485 }
 486
 487 static struct cpufreq_driver ve_spc_cpufreq_driver = {
 488         .name                   = "vexpress-spc",
 489         .flags                  = CPUFREQ_HAVE_GOVERNOR_PER_POLICY |
 490                                         CPUFREQ_NEED_INITIAL_FREQ_CHECK,
 491         .verify                 = cpufreq_generic_frequency_table_verify,
 492         .target_index           = ve_spc_cpufreq_set_target,
 493         .get                    = ve_spc_cpufreq_get_rate,
 494         .init                   = ve_spc_cpufreq_init,
 495         .exit                   = ve_spc_cpufreq_exit,
 496         .ready                  = ve_spc_cpufreq_ready,
 497         .attr                   = cpufreq_generic_attr,
 498 };
 499
 500 #ifdef CONFIG_BL_SWITCHER
 501 static int bL_cpufreq_switcher_notifier(struct notifier_block *nfb,
 502                                         unsigned long action, void *_arg)
 503 {
 504         pr_debug("%s: action: %ld\n", __func__, action);
 505
 506         switch (action) {
 507         case BL_NOTIFY_PRE_ENABLE:
 508         case BL_NOTIFY_PRE_DISABLE:
 509                 cpufreq_unregister_driver(&ve_spc_cpufreq_driver);
 510                 break;
 511
 512         case BL_NOTIFY_POST_ENABLE:
 513                 set_switching_enabled(true);
 514                 cpufreq_register_driver(&ve_spc_cpufreq_driver);
 515                 break;
 516
 517         case BL_NOTIFY_POST_DISABLE:
 518                 set_switching_enabled(false);
 519                 cpufreq_register_driver(&ve_spc_cpufreq_driver);
 520                 break;
 521
 522         default:
 523                 return NOTIFY_DONE;
 524         }
 525
 526         return NOTIFY_OK;
 527 }
 528
 529 static struct notifier_block bL_switcher_notifier = {
 530         .notifier_call = bL_cpufreq_switcher_notifier,
 531 };
 532
 533 static int __bLs_register_notifier(void)
 534 {
 535         return bL_switcher_register_notifier(&bL_switcher_notifier);
 536 }
 537
 538 static int __bLs_unregister_notifier(void)
 539 {
 540         return bL_switcher_unregister_notifier(&bL_switcher_notifier);
 541 }
 542 #else
 543 static int __bLs_register_notifier(void) { return 0; }
 544 static int __bLs_unregister_notifier(void) { return 0; }
 545 #endif
 546
 547 static int ve_spc_cpufreq_probe(struct platform_device *pdev)
 548 {
 549         int ret, i;
 550
 551         set_switching_enabled(bL_switcher_get_enabled());
 552
 553         for (i = 0; i < MAX_CLUSTERS; i++)
 554                 mutex_init(&cluster_lock[i]);
 555
 556         ret = cpufreq_register_driver(&ve_spc_cpufreq_driver);
 557         if (ret) {
 558                 pr_info("%s: Failed registering platform driver: %s, err: %d\n",
 559                         __func__, ve_spc_cpufreq_driver.name, ret);
 560         } else {
 561                 ret = __bLs_register_notifier();
 562                 if (ret)
 563                         cpufreq_unregister_driver(&ve_spc_cpufreq_driver);
 564                 else
 565                         pr_info("%s: Registered platform driver: %s\n",
 566                                 __func__, ve_spc_cpufreq_driver.name);
 567         }
 568
 569         bL_switcher_put_enabled();
 570         return ret;
 571 }
 572
 573 static int ve_spc_cpufreq_remove(struct platform_device *pdev)
 574 {
 575         bL_switcher_get_enabled();
 576         __bLs_unregister_notifier();
 577         cpufreq_unregister_driver(&ve_spc_cpufreq_driver);
 578         bL_switcher_put_enabled();
 579         pr_info("%s: Un-registered platform driver: %s\n", __func__,
 580                 ve_spc_cpufreq_driver.name);
 581         return 0;
 582 }
 583
 584 static struct platform_driver ve_spc_cpufreq_platdrv = {
 585         .driver = {
 586                 .name   = "vexpress-spc-cpufreq",
 587         },
 588         .probe          = ve_spc_cpufreq_probe,
 589         .remove         = ve_spc_cpufreq_remove,
 590 };
 591 module_platform_driver(ve_spc_cpufreq_platdrv);
 592
 593 MODULE_ALIAS("platform:vexpress-spc-cpufreq");
 594 MODULE_AUTHOR("Viresh Kumar <viresh.kumar@linaro.org>");
 595 MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>");
 596 MODULE_DESCRIPTION("Vexpress SPC ARM big LITTLE cpufreq driver");
 597 MODULE_LICENSE("GPL v2");