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
 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
 203static 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 */
 214static 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 */
 226static 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
 237static 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
 250static 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
 282static 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
 294static 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
 319static 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
 349out:
 350        dev_err(cpu_dev, "%s: Failed to get data for cluster: %d\n", __func__,
 351                cluster);
 352        return ret;
 353}
 354
 355static 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
 397put_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 */
 413static 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
 455static 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
 476static 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
 487static 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
 501static 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
 529static struct notifier_block bL_switcher_notifier = {
 530        .notifier_call = bL_cpufreq_switcher_notifier,
 531};
 532
 533static int __bLs_register_notifier(void)
 534{
 535        return bL_switcher_register_notifier(&bL_switcher_notifier);
 536}
 537
 538static int __bLs_unregister_notifier(void)
 539{
 540        return bL_switcher_unregister_notifier(&bL_switcher_notifier);
 541}
 542#else
 543static int __bLs_register_notifier(void) { return 0; }
 544static int __bLs_unregister_notifier(void) { return 0; }
 545#endif
 546
 547static 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
 573static 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
 584static 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};
 591module_platform_driver(ve_spc_cpufreq_platdrv);
 592
 593MODULE_ALIAS("platform:vexpress-spc-cpufreq");
 594MODULE_AUTHOR("Viresh Kumar <viresh.kumar@linaro.org>");
 595MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>");
 596MODULE_DESCRIPTION("Vexpress SPC ARM big LITTLE cpufreq driver");
 597MODULE_LICENSE("GPL v2");
 598