drivers/cpufreq/arm_big_little.c

   1 /*
   2  * ARM big.LITTLE Platforms CPUFreq support
   3  *
   4  * Copyright (C) 2013 ARM Ltd.
   5  * Sudeep KarkadaNagesha <sudeep.karkadanagesha@arm.com>
   6  *
   7  * Copyright (C) 2013 Linaro.
   8  * Viresh Kumar <viresh.kumar@linaro.org>
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License version 2 as
  12  * published by the Free Software Foundation.
  13  *
  14  * This program is distributed "as is" WITHOUT ANY WARRANTY of any
  15  * kind, whether express or implied; without even the implied warranty
  16  * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  17  * GNU General Public License for more details.
  18  */
  19
  20 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  21
  22 #include <linux/clk.h>
  23 #include <linux/cpu.h>
  24 #include <linux/cpufreq.h>
  25 #include <linux/cpumask.h>
  26 #include <linux/cpu_cooling.h>
  27 #include <linux/export.h>
  28 #include <linux/module.h>
  29 #include <linux/mutex.h>
  30 #include <linux/of_platform.h>
  31 #include <linux/pm_opp.h>
  32 #include <linux/slab.h>
  33 #include <linux/topology.h>
  34 #include <linux/types.h>
  35
  36 #include "arm_big_little.h"
  37
  38 /* Currently we support only two clusters */
  39 #define A15_CLUSTER     0
  40 #define A7_CLUSTER      1
  41 #define MAX_CLUSTERS    2
  42
  43 #ifdef CONFIG_BL_SWITCHER
  44 #include <asm/bL_switcher.h>
  45 static bool bL_switching_enabled;
  46 #define is_bL_switching_enabled()       bL_switching_enabled
  47 #define set_switching_enabled(x)        (bL_switching_enabled = (x))
  48 #else
  49 #define is_bL_switching_enabled()       false
  50 #define set_switching_enabled(x)        do { } while (0)
  51 #define bL_switch_request(...)          do { } while (0)
  52 #define bL_switcher_put_enabled()       do { } while (0)
  53 #define bL_switcher_get_enabled()       do { } while (0)
  54 #endif
  55
  56 #define ACTUAL_FREQ(cluster, freq)  ((cluster == A7_CLUSTER) ? freq << 1 : freq)
  57 #define VIRT_FREQ(cluster, freq)    ((cluster == A7_CLUSTER) ? freq >> 1 : freq)
  58
  59 static struct thermal_cooling_device *cdev[MAX_CLUSTERS];
  60 static struct cpufreq_arm_bL_ops *arm_bL_ops;
  61 static struct clk *clk[MAX_CLUSTERS];
  62 static struct cpufreq_frequency_table *freq_table[MAX_CLUSTERS + 1];
  63 static atomic_t cluster_usage[MAX_CLUSTERS + 1];
  64
  65 static unsigned int clk_big_min;        /* (Big) clock frequencies */
  66 static unsigned int clk_little_max;     /* Maximum clock frequency (Little) */
  67
  68 static DEFINE_PER_CPU(unsigned int, physical_cluster);
  69 static DEFINE_PER_CPU(unsigned int, cpu_last_req_freq);
  70
  71 static struct mutex cluster_lock[MAX_CLUSTERS];
  72
  73 static inline int raw_cpu_to_cluster(int cpu)
  74 {
  75         return topology_physical_package_id(cpu);
  76 }
  77
  78 static inline int cpu_to_cluster(int cpu)
  79 {
  80         return is_bL_switching_enabled() ?
  81                 MAX_CLUSTERS : raw_cpu_to_cluster(cpu);
  82 }
  83
  84 static unsigned int find_cluster_maxfreq(int cluster)
  85 {
  86         int j;
  87         u32 max_freq = 0, cpu_freq;
  88
  89         for_each_online_cpu(j) {
  90                 cpu_freq = per_cpu(cpu_last_req_freq, j);
  91
  92                 if ((cluster == per_cpu(physical_cluster, j)) &&
  93                                 (max_freq < cpu_freq))
  94                         max_freq = cpu_freq;
  95         }
  96
  97         pr_debug("%s: cluster: %d, max freq: %d\n", __func__, cluster,
  98                         max_freq);
  99
 100         return max_freq;
 101 }
 102
 103 static unsigned int clk_get_cpu_rate(unsigned int cpu)
 104 {
 105         u32 cur_cluster = per_cpu(physical_cluster, cpu);
 106         u32 rate = clk_get_rate(clk[cur_cluster]) / 1000;
 107
 108         /* For switcher we use virtual A7 clock rates */
 109         if (is_bL_switching_enabled())
 110                 rate = VIRT_FREQ(cur_cluster, rate);
 111
 112         pr_debug("%s: cpu: %d, cluster: %d, freq: %u\n", __func__, cpu,
 113                         cur_cluster, rate);
 114
 115         return rate;
 116 }
 117
 118 static unsigned int bL_cpufreq_get_rate(unsigned int cpu)
 119 {
 120         if (is_bL_switching_enabled()) {
 121                 pr_debug("%s: freq: %d\n", __func__, per_cpu(cpu_last_req_freq,
 122                                         cpu));
 123
 124                 return per_cpu(cpu_last_req_freq, cpu);
 125         } else {
 126                 return clk_get_cpu_rate(cpu);
 127         }
 128 }
 129
 130 static unsigned int
 131 bL_cpufreq_set_rate(u32 cpu, u32 old_cluster, u32 new_cluster, u32 rate)
 132 {
 133         u32 new_rate, prev_rate;
 134         int ret;
 135         bool bLs = is_bL_switching_enabled();
 136
 137         mutex_lock(&cluster_lock[new_cluster]);
 138
 139         if (bLs) {
 140                 prev_rate = per_cpu(cpu_last_req_freq, cpu);
 141                 per_cpu(cpu_last_req_freq, cpu) = rate;
 142                 per_cpu(physical_cluster, cpu) = new_cluster;
 143
 144                 new_rate = find_cluster_maxfreq(new_cluster);
 145                 new_rate = ACTUAL_FREQ(new_cluster, new_rate);
 146         } else {
 147                 new_rate = rate;
 148         }
 149
 150         pr_debug("%s: cpu: %d, old cluster: %d, new cluster: %d, freq: %d\n",
 151                         __func__, cpu, old_cluster, new_cluster, new_rate);
 152
 153         ret = clk_set_rate(clk[new_cluster], new_rate * 1000);
 154         if (!ret) {
 155                 /*
 156                  * FIXME: clk_set_rate hasn't returned an error here however it
 157                  * may be that clk_change_rate failed due to hardware or
 158                  * firmware issues and wasn't able to report that due to the
 159                  * current design of the clk core layer. To work around this
 160                  * problem we will read back the clock rate and check it is
 161                  * correct. This needs to be removed once clk core is fixed.
 162                  */
 163                 if (clk_get_rate(clk[new_cluster]) != new_rate * 1000)
 164                         ret = -EIO;
 165         }
 166
 167         if (WARN_ON(ret)) {
 168                 pr_err("clk_set_rate failed: %d, new cluster: %d\n", ret,
 169                                 new_cluster);
 170                 if (bLs) {
 171                         per_cpu(cpu_last_req_freq, cpu) = prev_rate;
 172                         per_cpu(physical_cluster, cpu) = old_cluster;
 173                 }
 174
 175                 mutex_unlock(&cluster_lock[new_cluster]);
 176
 177                 return ret;
 178         }
 179
 180         mutex_unlock(&cluster_lock[new_cluster]);
 181
 182         /* Recalc freq for old cluster when switching clusters */
 183         if (old_cluster != new_cluster) {
 184                 pr_debug("%s: cpu: %d, old cluster: %d, new cluster: %d\n",
 185                                 __func__, cpu, old_cluster, new_cluster);
 186
 187                 /* Switch cluster */
 188                 bL_switch_request(cpu, new_cluster);
 189
 190                 mutex_lock(&cluster_lock[old_cluster]);
 191
 192                 /* Set freq of old cluster if there are cpus left on it */
 193                 new_rate = find_cluster_maxfreq(old_cluster);
 194                 new_rate = ACTUAL_FREQ(old_cluster, new_rate);
 195
 196                 if (new_rate) {
 197                         pr_debug("%s: Updating rate of old cluster: %d, to freq: %d\n",
 198                                         __func__, old_cluster, new_rate);
 199
 200                         if (clk_set_rate(clk[old_cluster], new_rate * 1000))
 201                                 pr_err("%s: clk_set_rate failed: %d, old cluster: %d\n",
 202                                                 __func__, ret, old_cluster);
 203                 }
 204                 mutex_unlock(&cluster_lock[old_cluster]);
 205         }
 206
 207         return 0;
 208 }
 209
 210 /* Set clock frequency */
 211 static int bL_cpufreq_set_target(struct cpufreq_policy *policy,
 212                 unsigned int index)
 213 {
 214         u32 cpu = policy->cpu, cur_cluster, new_cluster, actual_cluster;
 215         unsigned int freqs_new;
 216
 217         cur_cluster = cpu_to_cluster(cpu);
 218         new_cluster = actual_cluster = per_cpu(physical_cluster, cpu);
 219
 220         freqs_new = freq_table[cur_cluster][index].frequency;
 221
 222         if (is_bL_switching_enabled()) {
 223                 if ((actual_cluster == A15_CLUSTER) &&
 224                                 (freqs_new < clk_big_min)) {
 225                         new_cluster = A7_CLUSTER;
 226                 } else if ((actual_cluster == A7_CLUSTER) &&
 227                                 (freqs_new > clk_little_max)) {
 228                         new_cluster = A15_CLUSTER;
 229                 }
 230         }
 231
 232         return bL_cpufreq_set_rate(cpu, actual_cluster, new_cluster, freqs_new);
 233 }
 234
 235 static inline u32 get_table_count(struct cpufreq_frequency_table *table)
 236 {
 237         int count;
 238
 239         for (count = 0; table[count].frequency != CPUFREQ_TABLE_END; count++)
 240                 ;
 241
 242         return count;
 243 }
 244
 245 /* get the minimum frequency in the cpufreq_frequency_table */
 246 static inline u32 get_table_min(struct cpufreq_frequency_table *table)
 247 {
 248         struct cpufreq_frequency_table *pos;
 249         uint32_t min_freq = ~0;
 250         cpufreq_for_each_entry(pos, table)
 251                 if (pos->frequency < min_freq)
 252                         min_freq = pos->frequency;
 253         return min_freq;
 254 }
 255
 256 /* get the maximum frequency in the cpufreq_frequency_table */
 257 static inline u32 get_table_max(struct cpufreq_frequency_table *table)
 258 {
 259         struct cpufreq_frequency_table *pos;
 260         uint32_t max_freq = 0;
 261         cpufreq_for_each_entry(pos, table)
 262                 if (pos->frequency > max_freq)
 263                         max_freq = pos->frequency;
 264         return max_freq;
 265 }
 266
 267 static int merge_cluster_tables(void)
 268 {
 269         int i, j, k = 0, count = 1;
 270         struct cpufreq_frequency_table *table;
 271
 272         for (i = 0; i < MAX_CLUSTERS; i++)
 273                 count += get_table_count(freq_table[i]);
 274
 275         table = kzalloc(sizeof(*table) * count, GFP_KERNEL);
 276         if (!table)
 277                 return -ENOMEM;
 278
 279         freq_table[MAX_CLUSTERS] = table;
 280
 281         /* Add in reverse order to get freqs in increasing order */
 282         for (i = MAX_CLUSTERS - 1; i >= 0; i--) {
 283                 for (j = 0; freq_table[i][j].frequency != CPUFREQ_TABLE_END;
 284                                 j++) {
 285                         table[k].frequency = VIRT_FREQ(i,
 286                                         freq_table[i][j].frequency);
 287                         pr_debug("%s: index: %d, freq: %d\n", __func__, k,
 288                                         table[k].frequency);
 289                         k++;
 290                 }
 291         }
 292
 293         table[k].driver_data = k;
 294         table[k].frequency = CPUFREQ_TABLE_END;
 295
 296         pr_debug("%s: End, table: %p, count: %d\n", __func__, table, k);
 297
 298         return 0;
 299 }
 300
 301 static void _put_cluster_clk_and_freq_table(struct device *cpu_dev)
 302 {
 303         u32 cluster = raw_cpu_to_cluster(cpu_dev->id);
 304
 305         if (!freq_table[cluster])
 306                 return;
 307
 308         clk_put(clk[cluster]);
 309         dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table[cluster]);
 310         if (arm_bL_ops->free_opp_table)
 311                 arm_bL_ops->free_opp_table(cpu_dev);
 312         dev_dbg(cpu_dev, "%s: cluster: %d\n", __func__, cluster);
 313 }
 314
 315 static void put_cluster_clk_and_freq_table(struct device *cpu_dev)
 316 {
 317         u32 cluster = cpu_to_cluster(cpu_dev->id);
 318         int i;
 319
 320         if (atomic_dec_return(&cluster_usage[cluster]))
 321                 return;
 322
 323         if (cluster < MAX_CLUSTERS)
 324                 return _put_cluster_clk_and_freq_table(cpu_dev);
 325
 326         for_each_present_cpu(i) {
 327                 struct device *cdev = get_cpu_device(i);
 328                 if (!cdev) {
 329                         pr_err("%s: failed to get cpu%d device\n", __func__, i);
 330                         return;
 331                 }
 332
 333                 _put_cluster_clk_and_freq_table(cdev);
 334         }
 335
 336         /* free virtual table */
 337         kfree(freq_table[cluster]);
 338 }
 339
 340 static int _get_cluster_clk_and_freq_table(struct device *cpu_dev)
 341 {
 342         u32 cluster = raw_cpu_to_cluster(cpu_dev->id);
 343         int ret;
 344
 345         if (freq_table[cluster])
 346                 return 0;
 347
 348         ret = arm_bL_ops->init_opp_table(cpu_dev);
 349         if (ret) {
 350                 dev_err(cpu_dev, "%s: init_opp_table failed, cpu: %d, err: %d\n",
 351                                 __func__, cpu_dev->id, ret);
 352                 goto out;
 353         }
 354
 355         ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table[cluster]);
 356         if (ret) {
 357                 dev_err(cpu_dev, "%s: failed to init cpufreq table, cpu: %d, err: %d\n",
 358                                 __func__, cpu_dev->id, ret);
 359                 goto free_opp_table;
 360         }
 361
 362         clk[cluster] = clk_get(cpu_dev, NULL);
 363         if (!IS_ERR(clk[cluster])) {
 364                 dev_dbg(cpu_dev, "%s: clk: %p & freq table: %p, cluster: %d\n",
 365                                 __func__, clk[cluster], freq_table[cluster],
 366                                 cluster);
 367                 return 0;
 368         }
 369
 370         dev_err(cpu_dev, "%s: Failed to get clk for cpu: %d, cluster: %d\n",
 371                         __func__, cpu_dev->id, cluster);
 372         ret = PTR_ERR(clk[cluster]);
 373         dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table[cluster]);
 374
 375 free_opp_table:
 376         if (arm_bL_ops->free_opp_table)
 377                 arm_bL_ops->free_opp_table(cpu_dev);
 378 out:
 379         dev_err(cpu_dev, "%s: Failed to get data for cluster: %d\n", __func__,
 380                         cluster);
 381         return ret;
 382 }
 383
 384 static int get_cluster_clk_and_freq_table(struct device *cpu_dev)
 385 {
 386         u32 cluster = cpu_to_cluster(cpu_dev->id);
 387         int i, ret;
 388
 389         if (atomic_inc_return(&cluster_usage[cluster]) != 1)
 390                 return 0;
 391
 392         if (cluster < MAX_CLUSTERS) {
 393                 ret = _get_cluster_clk_and_freq_table(cpu_dev);
 394                 if (ret)
 395                         atomic_dec(&cluster_usage[cluster]);
 396                 return ret;
 397         }
 398
 399         /*
 400          * Get data for all clusters and fill virtual cluster with a merge of
 401          * both
 402          */
 403         for_each_present_cpu(i) {
 404                 struct device *cdev = get_cpu_device(i);
 405                 if (!cdev) {
 406                         pr_err("%s: failed to get cpu%d device\n", __func__, i);
 407                         return -ENODEV;
 408                 }
 409
 410                 ret = _get_cluster_clk_and_freq_table(cdev);
 411                 if (ret)
 412                         goto put_clusters;
 413         }
 414
 415         ret = merge_cluster_tables();
 416         if (ret)
 417                 goto put_clusters;
 418
 419         /* Assuming 2 cluster, set clk_big_min and clk_little_max */
 420         clk_big_min = get_table_min(freq_table[0]);
 421         clk_little_max = VIRT_FREQ(1, get_table_max(freq_table[1]));
 422
 423         pr_debug("%s: cluster: %d, clk_big_min: %d, clk_little_max: %d\n",
 424                         __func__, cluster, clk_big_min, clk_little_max);
 425
 426         return 0;
 427
 428 put_clusters:
 429         for_each_present_cpu(i) {
 430                 struct device *cdev = get_cpu_device(i);
 431                 if (!cdev) {
 432                         pr_err("%s: failed to get cpu%d device\n", __func__, i);
 433                         return -ENODEV;
 434                 }
 435
 436                 _put_cluster_clk_and_freq_table(cdev);
 437         }
 438
 439         atomic_dec(&cluster_usage[cluster]);
 440
 441         return ret;
 442 }
 443
 444 /* Per-CPU initialization */
 445 static int bL_cpufreq_init(struct cpufreq_policy *policy)
 446 {
 447         u32 cur_cluster = cpu_to_cluster(policy->cpu);
 448         struct device *cpu_dev;
 449         int ret;
 450
 451         cpu_dev = get_cpu_device(policy->cpu);
 452         if (!cpu_dev) {
 453                 pr_err("%s: failed to get cpu%d device\n", __func__,
 454                                 policy->cpu);
 455                 return -ENODEV;
 456         }
 457
 458         ret = get_cluster_clk_and_freq_table(cpu_dev);
 459         if (ret)
 460                 return ret;
 461
 462         ret = cpufreq_table_validate_and_show(policy, freq_table[cur_cluster]);
 463         if (ret) {
 464                 dev_err(cpu_dev, "CPU %d, cluster: %d invalid freq table\n",
 465                                 policy->cpu, cur_cluster);
 466                 put_cluster_clk_and_freq_table(cpu_dev);
 467                 return ret;
 468         }
 469
 470         if (cur_cluster < MAX_CLUSTERS) {
 471                 int cpu;
 472
 473                 cpumask_copy(policy->cpus, topology_core_cpumask(policy->cpu));
 474
 475                 for_each_cpu(cpu, policy->cpus)
 476                         per_cpu(physical_cluster, cpu) = cur_cluster;
 477         } else {
 478                 /* Assumption: during init, we are always running on A15 */
 479                 per_cpu(physical_cluster, policy->cpu) = A15_CLUSTER;
 480         }
 481
 482         if (arm_bL_ops->get_transition_latency)
 483                 policy->cpuinfo.transition_latency =
 484                         arm_bL_ops->get_transition_latency(cpu_dev);
 485         else
 486                 policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
 487
 488         if (is_bL_switching_enabled())
 489                 per_cpu(cpu_last_req_freq, policy->cpu) = clk_get_cpu_rate(policy->cpu);
 490
 491         dev_info(cpu_dev, "%s: CPU %d initialized\n", __func__, policy->cpu);
 492         return 0;
 493 }
 494
 495 static int bL_cpufreq_exit(struct cpufreq_policy *policy)
 496 {
 497         struct device *cpu_dev;
 498         int cur_cluster = cpu_to_cluster(policy->cpu);
 499
 500         if (cur_cluster < MAX_CLUSTERS) {
 501                 cpufreq_cooling_unregister(cdev[cur_cluster]);
 502                 cdev[cur_cluster] = NULL;
 503         }
 504
 505         cpu_dev = get_cpu_device(policy->cpu);
 506         if (!cpu_dev) {
 507                 pr_err("%s: failed to get cpu%d device\n", __func__,
 508                                 policy->cpu);
 509                 return -ENODEV;
 510         }
 511
 512         put_cluster_clk_and_freq_table(cpu_dev);
 513         dev_dbg(cpu_dev, "%s: Exited, cpu: %d\n", __func__, policy->cpu);
 514
 515         return 0;
 516 }
 517
 518 static void bL_cpufreq_ready(struct cpufreq_policy *policy)
 519 {
 520         struct device *cpu_dev = get_cpu_device(policy->cpu);
 521         int cur_cluster = cpu_to_cluster(policy->cpu);
 522         struct device_node *np;
 523
 524         /* Do not register a cpu_cooling device if we are in IKS mode */
 525         if (cur_cluster >= MAX_CLUSTERS)
 526                 return;
 527
 528         np = of_node_get(cpu_dev->of_node);
 529         if (WARN_ON(!np))
 530                 return;
 531
 532         if (of_find_property(np, "#cooling-cells", NULL)) {
 533                 u32 power_coefficient = 0;
 534
 535                 of_property_read_u32(np, "dynamic-power-coefficient",
 536                                      &power_coefficient);
 537
 538                 cdev[cur_cluster] = of_cpufreq_power_cooling_register(np,
 539                                 policy->related_cpus, power_coefficient, NULL);
 540                 if (IS_ERR(cdev[cur_cluster])) {
 541                         dev_err(cpu_dev,
 542                                 "running cpufreq without cooling device: %ld\n",
 543                                 PTR_ERR(cdev[cur_cluster]));
 544                         cdev[cur_cluster] = NULL;
 545                 }
 546         }
 547         of_node_put(np);
 548 }
 549
 550 static struct cpufreq_driver bL_cpufreq_driver = {
 551         .name                   = "arm-big-little",
 552         .flags                  = CPUFREQ_STICKY |
 553                                         CPUFREQ_HAVE_GOVERNOR_PER_POLICY |
 554                                         CPUFREQ_NEED_INITIAL_FREQ_CHECK,
 555         .verify                 = cpufreq_generic_frequency_table_verify,
 556         .target_index           = bL_cpufreq_set_target,
 557         .get                    = bL_cpufreq_get_rate,
 558         .init                   = bL_cpufreq_init,
 559         .exit                   = bL_cpufreq_exit,
 560         .ready                  = bL_cpufreq_ready,
 561         .attr                   = cpufreq_generic_attr,
 562 };
 563
 564 #ifdef CONFIG_BL_SWITCHER
 565 static int bL_cpufreq_switcher_notifier(struct notifier_block *nfb,
 566                                         unsigned long action, void *_arg)
 567 {
 568         pr_debug("%s: action: %ld\n", __func__, action);
 569
 570         switch (action) {
 571         case BL_NOTIFY_PRE_ENABLE:
 572         case BL_NOTIFY_PRE_DISABLE:
 573                 cpufreq_unregister_driver(&bL_cpufreq_driver);
 574                 break;
 575
 576         case BL_NOTIFY_POST_ENABLE:
 577                 set_switching_enabled(true);
 578                 cpufreq_register_driver(&bL_cpufreq_driver);
 579                 break;
 580
 581         case BL_NOTIFY_POST_DISABLE:
 582                 set_switching_enabled(false);
 583                 cpufreq_register_driver(&bL_cpufreq_driver);
 584                 break;
 585
 586         default:
 587                 return NOTIFY_DONE;
 588         }
 589
 590         return NOTIFY_OK;
 591 }
 592
 593 static struct notifier_block bL_switcher_notifier = {
 594         .notifier_call = bL_cpufreq_switcher_notifier,
 595 };
 596
 597 static int __bLs_register_notifier(void)
 598 {
 599         return bL_switcher_register_notifier(&bL_switcher_notifier);
 600 }
 601
 602 static int __bLs_unregister_notifier(void)
 603 {
 604         return bL_switcher_unregister_notifier(&bL_switcher_notifier);
 605 }
 606 #else
 607 static int __bLs_register_notifier(void) { return 0; }
 608 static int __bLs_unregister_notifier(void) { return 0; }
 609 #endif
 610
 611 int bL_cpufreq_register(struct cpufreq_arm_bL_ops *ops)
 612 {
 613         int ret, i;
 614
 615         if (arm_bL_ops) {
 616                 pr_debug("%s: Already registered: %s, exiting\n", __func__,
 617                                 arm_bL_ops->name);
 618                 return -EBUSY;
 619         }
 620
 621         if (!ops || !strlen(ops->name) || !ops->init_opp_table) {
 622                 pr_err("%s: Invalid arm_bL_ops, exiting\n", __func__);
 623                 return -ENODEV;
 624         }
 625
 626         arm_bL_ops = ops;
 627
 628         set_switching_enabled(bL_switcher_get_enabled());
 629
 630         for (i = 0; i < MAX_CLUSTERS; i++)
 631                 mutex_init(&cluster_lock[i]);
 632
 633         ret = cpufreq_register_driver(&bL_cpufreq_driver);
 634         if (ret) {
 635                 pr_info("%s: Failed registering platform driver: %s, err: %d\n",
 636                                 __func__, ops->name, ret);
 637                 arm_bL_ops = NULL;
 638         } else {
 639                 ret = __bLs_register_notifier();
 640                 if (ret) {
 641                         cpufreq_unregister_driver(&bL_cpufreq_driver);
 642                         arm_bL_ops = NULL;
 643                 } else {
 644                         pr_info("%s: Registered platform driver: %s\n",
 645                                         __func__, ops->name);
 646                 }
 647         }
 648
 649         bL_switcher_put_enabled();
 650         return ret;
 651 }
 652 EXPORT_SYMBOL_GPL(bL_cpufreq_register);
 653
 654 void bL_cpufreq_unregister(struct cpufreq_arm_bL_ops *ops)
 655 {
 656         if (arm_bL_ops != ops) {
 657                 pr_err("%s: Registered with: %s, can't unregister, exiting\n",
 658                                 __func__, arm_bL_ops->name);
 659                 return;
 660         }
 661
 662         bL_switcher_get_enabled();
 663         __bLs_unregister_notifier();
 664         cpufreq_unregister_driver(&bL_cpufreq_driver);
 665         bL_switcher_put_enabled();
 666         pr_info("%s: Un-registered platform driver: %s\n", __func__,
 667                         arm_bL_ops->name);
 668         arm_bL_ops = NULL;
 669 }
 670 EXPORT_SYMBOL_GPL(bL_cpufreq_unregister);
 671
 672 MODULE_AUTHOR("Viresh Kumar <viresh.kumar@linaro.org>");
 673 MODULE_DESCRIPTION("Generic ARM big LITTLE cpufreq driver");
 674 MODULE_LICENSE("GPL v2");