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 <[email protected]>
   7  *
   8  * Copyright (C) 2013 Linaro.
   9  * Viresh Kumar <[email protected]>
  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         pr_debug("%s: cluster: %d, max freq: %d\n", __func__, cluster,
  88                         max_freq);
  89
  90         return max_freq;
  91 }
  92
  93 static unsigned int clk_get_cpu_rate(unsigned int cpu)
  94 {
  95         u32 cur_cluster = per_cpu(physical_cluster, cpu);
  96         u32 rate = clk_get_rate(clk[cur_cluster]) / 1000;
  97
  98         /* For switcher we use virtual A7 clock rates */
  99         if (is_bL_switching_enabled())
 100                 rate = VIRT_FREQ(cur_cluster, rate);
 101
 102         pr_debug("%s: cpu: %d, cluster: %d, freq: %u\n", __func__, cpu,
 103                         cur_cluster, rate);
 104
 105         return rate;
 106 }
 107
 108 static unsigned int ve_spc_cpufreq_get_rate(unsigned int cpu)
 109 {
 110         if (is_bL_switching_enabled()) {
 111                 pr_debug("%s: freq: %d\n", __func__, per_cpu(cpu_last_req_freq,
 112                                         cpu));
 113
 114                 return per_cpu(cpu_last_req_freq, cpu);
 115         } else {
 116                 return clk_get_cpu_rate(cpu);
 117         }
 118 }
 119
 120 static unsigned int
 121 ve_spc_cpufreq_set_rate(u32 cpu, u32 old_cluster, u32 new_cluster, u32 rate)
 122 {
 123         u32 new_rate, prev_rate;
 124         int ret;
 125         bool bLs = is_bL_switching_enabled();
 126
 127         mutex_lock(&cluster_lock[new_cluster]);
 128
 129         if (bLs) {
 130                 prev_rate = per_cpu(cpu_last_req_freq, cpu);
 131                 per_cpu(cpu_last_req_freq, cpu) = rate;
 132                 per_cpu(physical_cluster, cpu) = new_cluster;
 133
 134                 new_rate = find_cluster_maxfreq(new_cluster);
 135                 new_rate = ACTUAL_FREQ(new_cluster, new_rate);
 136         } else {
 137                 new_rate = rate;
 138         }
 139
 140         pr_debug("%s: cpu: %d, old cluster: %d, new cluster: %d, freq: %d\n",
 141                         __func__, cpu, old_cluster, new_cluster, new_rate);
 142
 143         ret = clk_set_rate(clk[new_cluster], new_rate * 1000);
 144         if (!ret) {
 145                 /*
 146                  * FIXME: clk_set_rate hasn't returned an error here however it
 147                  * may be that clk_change_rate failed due to hardware or
 148                  * firmware issues and wasn't able to report that due to the
 149                  * current design of the clk core layer. To work around this
 150                  * problem we will read back the clock rate and check it is
 151                  * correct. This needs to be removed once clk core is fixed.
 152                  */
 153                 if (clk_get_rate(clk[new_cluster]) != new_rate * 1000)
 154                         ret = -EIO;
 155         }
 156
 157         if (WARN_ON(ret)) {
 158                 pr_err("clk_set_rate failed: %d, new cluster: %d\n", ret,
 159                                 new_cluster);
 160                 if (bLs) {
 161                         per_cpu(cpu_last_req_freq, cpu) = prev_rate;
 162                         per_cpu(physical_cluster, cpu) = old_cluster;
 163                 }
 164
 165                 mutex_unlock(&cluster_lock[new_cluster]);
 166
 167                 return ret;
 168         }
 169
 170         mutex_unlock(&cluster_lock[new_cluster]);
 171
 172         /* Recalc freq for old cluster when switching clusters */
 173         if (old_cluster != new_cluster) {
 174                 pr_debug("%s: cpu: %d, old cluster: %d, new cluster: %d\n",
 175                                 __func__, cpu, old_cluster, new_cluster);
 176
 177                 /* Switch cluster */
 178                 bL_switch_request(cpu, new_cluster);
 179
 180                 mutex_lock(&cluster_lock[old_cluster]);
 181
 182                 /* Set freq of old cluster if there are cpus left on it */
 183                 new_rate = find_cluster_maxfreq(old_cluster);
 184                 new_rate = ACTUAL_FREQ(old_cluster, new_rate);
 185
 186                 if (new_rate) {
 187                         pr_debug("%s: Updating rate of old cluster: %d, to freq: %d\n",
 188                                         __func__, old_cluster, new_rate);
 189
 190                         if (clk_set_rate(clk[old_cluster], new_rate * 1000))
 191                                 pr_err("%s: clk_set_rate failed: %d, old cluster: %d\n",
 192                                                 __func__, ret, old_cluster);
 193                 }
 194                 mutex_unlock(&cluster_lock[old_cluster]);
 195         }
 196
 197         return 0;
 198 }
 199
 200 /* Set clock frequency */
 201 static int ve_spc_cpufreq_set_target(struct cpufreq_policy *policy,
 202                                      unsigned int index)
 203 {
 204         u32 cpu = policy->cpu, cur_cluster, new_cluster, actual_cluster;
 205         unsigned int freqs_new;
 206         int ret;
 207
 208         cur_cluster = cpu_to_cluster(cpu);
 209         new_cluster = actual_cluster = per_cpu(physical_cluster, cpu);
 210
 211         freqs_new = freq_table[cur_cluster][index].frequency;
 212
 213         if (is_bL_switching_enabled()) {
 214                 if ((actual_cluster == A15_CLUSTER) &&
 215                                 (freqs_new < clk_big_min)) {
 216                         new_cluster = A7_CLUSTER;
 217                 } else if ((actual_cluster == A7_CLUSTER) &&
 218                                 (freqs_new > clk_little_max)) {
 219                         new_cluster = A15_CLUSTER;
 220                 }
 221         }
 222
 223         ret = ve_spc_cpufreq_set_rate(cpu, actual_cluster, new_cluster,
 224                                       freqs_new);
 225
 226         if (!ret) {
 227                 arch_set_freq_scale(policy->related_cpus, freqs_new,
 228                                     policy->cpuinfo.max_freq);
 229         }
 230
 231         return ret;
 232 }
 233
 234 static inline u32 get_table_count(struct cpufreq_frequency_table *table)
 235 {
 236         int count;
 237
 238         for (count = 0; table[count].frequency != CPUFREQ_TABLE_END; count++)
 239                 ;
 240
 241         return count;
 242 }
 243
 244 /* get the minimum frequency in the cpufreq_frequency_table */
 245 static inline u32 get_table_min(struct cpufreq_frequency_table *table)
 246 {
 247         struct cpufreq_frequency_table *pos;
 248         uint32_t min_freq = ~0;
 249         cpufreq_for_each_entry(pos, table)
 250                 if (pos->frequency < min_freq)
 251                         min_freq = pos->frequency;
 252         return min_freq;
 253 }
 254
 255 /* get the maximum frequency in the cpufreq_frequency_table */
 256 static inline u32 get_table_max(struct cpufreq_frequency_table *table)
 257 {
 258         struct cpufreq_frequency_table *pos;
 259         uint32_t max_freq = 0;
 260         cpufreq_for_each_entry(pos, table)
 261                 if (pos->frequency > max_freq)
 262                         max_freq = pos->frequency;
 263         return max_freq;
 264 }
 265
 266 static int merge_cluster_tables(void)
 267 {
 268         int i, j, k = 0, count = 1;
 269         struct cpufreq_frequency_table *table;
 270
 271         for (i = 0; i < MAX_CLUSTERS; i++)
 272                 count += get_table_count(freq_table[i]);
 273
 274         table = kcalloc(count, sizeof(*table), GFP_KERNEL);
 275         if (!table)
 276                 return -ENOMEM;
 277
 278         freq_table[MAX_CLUSTERS] = table;
 279
 280         /* Add in reverse order to get freqs in increasing order */
 281         for (i = MAX_CLUSTERS - 1; i >= 0; i--) {
 282                 for (j = 0; freq_table[i][j].frequency != CPUFREQ_TABLE_END;
 283                                 j++) {
 284                         table[k].frequency = VIRT_FREQ(i,
 285                                         freq_table[i][j].frequency);
 286                         pr_debug("%s: index: %d, freq: %d\n", __func__, k,
 287                                         table[k].frequency);
 288                         k++;
 289                 }
 290         }
 291
 292         table[k].driver_data = k;
 293         table[k].frequency = CPUFREQ_TABLE_END;
 294
 295         pr_debug("%s: End, table: %p, count: %d\n", __func__, table, k);
 296
 297         return 0;
 298 }
 299
 300 static void _put_cluster_clk_and_freq_table(struct device *cpu_dev,
 301                                             const struct cpumask *cpumask)
 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         dev_dbg(cpu_dev, "%s: cluster: %d\n", __func__, cluster);
 311 }
 312
 313 static void put_cluster_clk_and_freq_table(struct device *cpu_dev,
 314                                            const struct cpumask *cpumask)
 315 {
 316         u32 cluster = cpu_to_cluster(cpu_dev->id);
 317         int i;
 318
 319         if (atomic_dec_return(&cluster_usage[cluster]))
 320                 return;
 321
 322         if (cluster < MAX_CLUSTERS)
 323                 return _put_cluster_clk_and_freq_table(cpu_dev, cpumask);
 324
 325         for_each_present_cpu(i) {
 326                 struct device *cdev = get_cpu_device(i);
 327                 if (!cdev) {
 328                         pr_err("%s: failed to get cpu%d device\n", __func__, i);
 329                         return;
 330                 }
 331
 332                 _put_cluster_clk_and_freq_table(cdev, cpumask);
 333         }
 334
 335         /* free virtual table */
 336         kfree(freq_table[cluster]);
 337 }
 338
 339 static int _get_cluster_clk_and_freq_table(struct device *cpu_dev,
 340                                            const struct cpumask *cpumask)
 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         /*
 349          * platform specific SPC code must initialise the opp table
 350          * so just check if the OPP count is non-zero
 351          */
 352         ret = dev_pm_opp_get_opp_count(cpu_dev) <= 0;
 353         if (ret)
 354                 goto out;
 355
 356         ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table[cluster]);
 357         if (ret) {
 358                 dev_err(cpu_dev, "%s: failed to init cpufreq table, cpu: %d, err: %d\n",
 359                                 __func__, cpu_dev->id, ret);
 360                 goto out;
 361         }
 362
 363         clk[cluster] = clk_get(cpu_dev, NULL);
 364         if (!IS_ERR(clk[cluster])) {
 365                 dev_dbg(cpu_dev, "%s: clk: %p & freq table: %p, cluster: %d\n",
 366                                 __func__, clk[cluster], freq_table[cluster],
 367                                 cluster);
 368                 return 0;
 369         }
 370
 371         dev_err(cpu_dev, "%s: Failed to get clk for cpu: %d, cluster: %d\n",
 372                         __func__, cpu_dev->id, cluster);
 373         ret = PTR_ERR(clk[cluster]);
 374         dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table[cluster]);
 375
 376 out:
 377         dev_err(cpu_dev, "%s: Failed to get data for cluster: %d\n", __func__,
 378                         cluster);
 379         return ret;
 380 }
 381
 382 static int get_cluster_clk_and_freq_table(struct device *cpu_dev,
 383                                           const struct cpumask *cpumask)
 384 {
 385         u32 cluster = cpu_to_cluster(cpu_dev->id);
 386         int i, ret;
 387
 388         if (atomic_inc_return(&cluster_usage[cluster]) != 1)
 389                 return 0;
 390
 391         if (cluster < MAX_CLUSTERS) {
 392                 ret = _get_cluster_clk_and_freq_table(cpu_dev, cpumask);
 393                 if (ret)
 394                         atomic_dec(&cluster_usage[cluster]);
 395                 return ret;
 396         }
 397
 398         /*
 399          * Get data for all clusters and fill virtual cluster with a merge of
 400          * both
 401          */
 402         for_each_present_cpu(i) {
 403                 struct device *cdev = get_cpu_device(i);
 404                 if (!cdev) {
 405                         pr_err("%s: failed to get cpu%d device\n", __func__, i);
 406                         return -ENODEV;
 407                 }
 408
 409                 ret = _get_cluster_clk_and_freq_table(cdev, cpumask);
 410                 if (ret)
 411                         goto put_clusters;
 412         }
 413
 414         ret = merge_cluster_tables();
 415         if (ret)
 416                 goto put_clusters;
 417
 418         /* Assuming 2 cluster, set clk_big_min and clk_little_max */
 419         clk_big_min = get_table_min(freq_table[0]);
 420         clk_little_max = VIRT_FREQ(1, get_table_max(freq_table[1]));
 421
 422         pr_debug("%s: cluster: %d, clk_big_min: %d, clk_little_max: %d\n",
 423                         __func__, cluster, clk_big_min, clk_little_max);
 424
 425         return 0;
 426
 427 put_clusters:
 428         for_each_present_cpu(i) {
 429                 struct device *cdev = get_cpu_device(i);
 430                 if (!cdev) {
 431                         pr_err("%s: failed to get cpu%d device\n", __func__, i);
 432                         return -ENODEV;
 433                 }
 434
 435                 _put_cluster_clk_and_freq_table(cdev, cpumask);
 436         }
 437
 438         atomic_dec(&cluster_usage[cluster]);
 439
 440         return ret;
 441 }
 442
 443 /* Per-CPU initialization */
 444 static int ve_spc_cpufreq_init(struct cpufreq_policy *policy)
 445 {
 446         u32 cur_cluster = cpu_to_cluster(policy->cpu);
 447         struct device *cpu_dev;
 448         int ret;
 449
 450         cpu_dev = get_cpu_device(policy->cpu);
 451         if (!cpu_dev) {
 452                 pr_err("%s: failed to get cpu%d device\n", __func__,
 453                                 policy->cpu);
 454                 return -ENODEV;
 455         }
 456
 457         if (cur_cluster < MAX_CLUSTERS) {
 458                 int cpu;
 459
 460                 cpumask_copy(policy->cpus, topology_core_cpumask(policy->cpu));
 461
 462                 for_each_cpu(cpu, policy->cpus)
 463                         per_cpu(physical_cluster, cpu) = cur_cluster;
 464         } else {
 465                 /* Assumption: during init, we are always running on A15 */
 466                 per_cpu(physical_cluster, policy->cpu) = A15_CLUSTER;
 467         }
 468
 469         ret = get_cluster_clk_and_freq_table(cpu_dev, policy->cpus);
 470         if (ret)
 471                 return ret;
 472
 473         policy->freq_table = freq_table[cur_cluster];
 474         policy->cpuinfo.transition_latency = 1000000; /* 1 ms */
 475
 476         dev_pm_opp_of_register_em(policy->cpus);
 477
 478         if (is_bL_switching_enabled())
 479                 per_cpu(cpu_last_req_freq, policy->cpu) = clk_get_cpu_rate(policy->cpu);
 480
 481         dev_info(cpu_dev, "%s: CPU %d initialized\n", __func__, policy->cpu);
 482         return 0;
 483 }
 484
 485 static int ve_spc_cpufreq_exit(struct cpufreq_policy *policy)
 486 {
 487         struct device *cpu_dev;
 488         int cur_cluster = cpu_to_cluster(policy->cpu);
 489
 490         if (cur_cluster < MAX_CLUSTERS) {
 491                 cpufreq_cooling_unregister(cdev[cur_cluster]);
 492                 cdev[cur_cluster] = NULL;
 493         }
 494
 495         cpu_dev = get_cpu_device(policy->cpu);
 496         if (!cpu_dev) {
 497                 pr_err("%s: failed to get cpu%d device\n", __func__,
 498                                 policy->cpu);
 499                 return -ENODEV;
 500         }
 501
 502         put_cluster_clk_and_freq_table(cpu_dev, policy->related_cpus);
 503         dev_dbg(cpu_dev, "%s: Exited, cpu: %d\n", __func__, policy->cpu);
 504
 505         return 0;
 506 }
 507
 508 static void ve_spc_cpufreq_ready(struct cpufreq_policy *policy)
 509 {
 510         int cur_cluster = cpu_to_cluster(policy->cpu);
 511
 512         /* Do not register a cpu_cooling device if we are in IKS mode */
 513         if (cur_cluster >= MAX_CLUSTERS)
 514                 return;
 515
 516         cdev[cur_cluster] = of_cpufreq_cooling_register(policy);
 517 }
 518
 519 static struct cpufreq_driver ve_spc_cpufreq_driver = {
 520         .name                   = "vexpress-spc",
 521         .flags                  = CPUFREQ_STICKY |
 522                                         CPUFREQ_HAVE_GOVERNOR_PER_POLICY |
 523                                         CPUFREQ_NEED_INITIAL_FREQ_CHECK,
 524         .verify                 = cpufreq_generic_frequency_table_verify,
 525         .target_index           = ve_spc_cpufreq_set_target,
 526         .get                    = ve_spc_cpufreq_get_rate,
 527         .init                   = ve_spc_cpufreq_init,
 528         .exit                   = ve_spc_cpufreq_exit,
 529         .ready                  = ve_spc_cpufreq_ready,
 530         .attr                   = cpufreq_generic_attr,
 531 };
 532
 533 #ifdef CONFIG_BL_SWITCHER
 534 static int bL_cpufreq_switcher_notifier(struct notifier_block *nfb,
 535                                         unsigned long action, void *_arg)
 536 {
 537         pr_debug("%s: action: %ld\n", __func__, action);
 538
 539         switch (action) {
 540         case BL_NOTIFY_PRE_ENABLE:
 541         case BL_NOTIFY_PRE_DISABLE:
 542                 cpufreq_unregister_driver(&ve_spc_cpufreq_driver);
 543                 break;
 544
 545         case BL_NOTIFY_POST_ENABLE:
 546                 set_switching_enabled(true);
 547                 cpufreq_register_driver(&ve_spc_cpufreq_driver);
 548                 break;
 549
 550         case BL_NOTIFY_POST_DISABLE:
 551                 set_switching_enabled(false);
 552                 cpufreq_register_driver(&ve_spc_cpufreq_driver);
 553                 break;
 554
 555         default:
 556                 return NOTIFY_DONE;
 557         }
 558
 559         return NOTIFY_OK;
 560 }
 561
 562 static struct notifier_block bL_switcher_notifier = {
 563         .notifier_call = bL_cpufreq_switcher_notifier,
 564 };
 565
 566 static int __bLs_register_notifier(void)
 567 {
 568         return bL_switcher_register_notifier(&bL_switcher_notifier);
 569 }
 570
 571 static int __bLs_unregister_notifier(void)
 572 {
 573         return bL_switcher_unregister_notifier(&bL_switcher_notifier);
 574 }
 575 #else
 576 static int __bLs_register_notifier(void) { return 0; }
 577 static int __bLs_unregister_notifier(void) { return 0; }
 578 #endif
 579
 580 static int ve_spc_cpufreq_probe(struct platform_device *pdev)
 581 {
 582         int ret, i;
 583
 584         set_switching_enabled(bL_switcher_get_enabled());
 585
 586         for (i = 0; i < MAX_CLUSTERS; i++)
 587                 mutex_init(&cluster_lock[i]);
 588
 589         ret = cpufreq_register_driver(&ve_spc_cpufreq_driver);
 590         if (ret) {
 591                 pr_info("%s: Failed registering platform driver: %s, err: %d\n",
 592                         __func__, ve_spc_cpufreq_driver.name, ret);
 593         } else {
 594                 ret = __bLs_register_notifier();
 595                 if (ret)
 596                         cpufreq_unregister_driver(&ve_spc_cpufreq_driver);
 597                 else
 598                         pr_info("%s: Registered platform driver: %s\n",
 599                                 __func__, ve_spc_cpufreq_driver.name);
 600         }
 601
 602         bL_switcher_put_enabled();
 603         return ret;
 604 }
 605
 606 static int ve_spc_cpufreq_remove(struct platform_device *pdev)
 607 {
 608         bL_switcher_get_enabled();
 609         __bLs_unregister_notifier();
 610         cpufreq_unregister_driver(&ve_spc_cpufreq_driver);
 611         bL_switcher_put_enabled();
 612         pr_info("%s: Un-registered platform driver: %s\n", __func__,
 613                 ve_spc_cpufreq_driver.name);
 614         return 0;
 615 }
 616
 617 static struct platform_driver ve_spc_cpufreq_platdrv = {
 618         .driver = {
 619                 .name   = "vexpress-spc-cpufreq",
 620         },
 621         .probe          = ve_spc_cpufreq_probe,
 622         .remove         = ve_spc_cpufreq_remove,
 623 };
 624 module_platform_driver(ve_spc_cpufreq_platdrv);
 625
 626 MODULE_AUTHOR("Viresh Kumar <[email protected]>");
 627 MODULE_AUTHOR("Sudeep Holla <[email protected]>");
 628 MODULE_DESCRIPTION("Vexpress SPC ARM big LITTLE cpufreq driver");
 629 MODULE_LICENSE("GPL v2");