linux/drivers/cpufreq/vexpress-spc-cpufreq.c
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   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>
  36static 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
  50static struct thermal_cooling_device *cdev[MAX_CLUSTERS];
  51static struct clk *clk[MAX_CLUSTERS];
  52static struct cpufreq_frequency_table *freq_table[MAX_CLUSTERS + 1];
  53static atomic_t cluster_usage[MAX_CLUSTERS + 1];
  54
  55static unsigned int clk_big_min;        /* (Big) clock frequencies */
  56static unsigned int clk_little_max;     /* Maximum clock frequency (Little) */
  57
  58static DEFINE_PER_CPU(unsigned int, physical_cluster);
  59static DEFINE_PER_CPU(unsigned int, cpu_last_req_freq);
  60
  61static struct mutex cluster_lock[MAX_CLUSTERS];
  62
  63static inline int raw_cpu_to_cluster(int cpu)
  64{
  65        return topology_physical_package_id(cpu);
  66}
  67
  68static inline int cpu_to_cluster(int cpu)
  69{
  70        return is_bL_switching_enabled() ?
  71                MAX_CLUSTERS : raw_cpu_to_cluster(cpu);
  72}
  73
  74static 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
  90static 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
 102static 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
 110static unsigned int
 111ve_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 */
 180static 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
 211static 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 */
 222static 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 */
 234static 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
 245static 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
 258static 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
 290static 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
 302static 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
 327static 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
 357out:
 358        dev_err(cpu_dev, "%s: Failed to get data for cluster: %d\n", __func__,
 359                cluster);
 360        return ret;
 361}
 362
 363static 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
 405put_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 */
 421static 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(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
 463static 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
 484static 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
 495static 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
 510static 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
 538static struct notifier_block bL_switcher_notifier = {
 539        .notifier_call = bL_cpufreq_switcher_notifier,
 540};
 541
 542static int __bLs_register_notifier(void)
 543{
 544        return bL_switcher_register_notifier(&bL_switcher_notifier);
 545}
 546
 547static int __bLs_unregister_notifier(void)
 548{
 549        return bL_switcher_unregister_notifier(&bL_switcher_notifier);
 550}
 551#else
 552static int __bLs_register_notifier(void) { return 0; }
 553static int __bLs_unregister_notifier(void) { return 0; }
 554#endif
 555
 556static 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
 582static 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
 593static 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};
 600module_platform_driver(ve_spc_cpufreq_platdrv);
 601
 602MODULE_AUTHOR("Viresh Kumar <viresh.kumar@linaro.org>");
 603MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>");
 604MODULE_DESCRIPTION("Vexpress SPC ARM big LITTLE cpufreq driver");
 605MODULE_LICENSE("GPL v2");
 606