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/export.h>
  27 #include <linux/mutex.h>
  28 #include <linux/of_platform.h>
  29 #include <linux/pm_opp.h>
  30 #include <linux/slab.h>
  31 #include <linux/topology.h>
  32 #include <linux/types.h>
  33 #include <asm/bL_switcher.h>
  34
  35 #include "arm_big_little.h"
  36
  37 /* Currently we support only two clusters */
  38 #define A15_CLUSTER     0
  39 #define A7_CLUSTER      1
  40 #define MAX_CLUSTERS    2
  41
  42 #ifdef CONFIG_BL_SWITCHER
  43 #define is_bL_switching_enabled()       true
  44 #else
  45 #define is_bL_switching_enabled()       false
  46 #endif
  47
  48 #define ACTUAL_FREQ(cluster, freq)  ((cluster == A7_CLUSTER) ? freq << 1 : freq)
  49 #define VIRT_FREQ(cluster, freq)    ((cluster == A7_CLUSTER) ? freq >> 1 : freq)
  50
  51 static struct cpufreq_arm_bL_ops *arm_bL_ops;
  52 static struct clk *clk[MAX_CLUSTERS];
  53 static struct cpufreq_frequency_table *freq_table[MAX_CLUSTERS + 1];
  54 static atomic_t cluster_usage[MAX_CLUSTERS + 1];
  55
  56 static unsigned int clk_big_min;        /* (Big) clock frequencies */
  57 static unsigned int clk_little_max;     /* Maximum clock frequency (Little) */
  58
  59 static DEFINE_PER_CPU(unsigned int, physical_cluster);
  60 static DEFINE_PER_CPU(unsigned int, cpu_last_req_freq);
  61
  62 static struct mutex cluster_lock[MAX_CLUSTERS];
  63
  64 static inline int raw_cpu_to_cluster(int cpu)
  65 {
  66         return topology_physical_package_id(cpu);
  67 }
  68
  69 static inline int cpu_to_cluster(int cpu)
  70 {
  71         return is_bL_switching_enabled() ?
  72                 MAX_CLUSTERS : raw_cpu_to_cluster(cpu);
  73 }
  74
  75 static unsigned int find_cluster_maxfreq(int cluster)
  76 {
  77         int j;
  78         u32 max_freq = 0, cpu_freq;
  79
  80         for_each_online_cpu(j) {
  81                 cpu_freq = per_cpu(cpu_last_req_freq, j);
  82
  83                 if ((cluster == per_cpu(physical_cluster, j)) &&
  84                                 (max_freq < cpu_freq))
  85                         max_freq = cpu_freq;
  86         }
  87
  88         pr_debug("%s: cluster: %d, max freq: %d\n", __func__, cluster,
  89                         max_freq);
  90
  91         return max_freq;
  92 }
  93
  94 static unsigned int clk_get_cpu_rate(unsigned int cpu)
  95 {
  96         u32 cur_cluster = per_cpu(physical_cluster, cpu);
  97         u32 rate = clk_get_rate(clk[cur_cluster]) / 1000;
  98
  99         /* For switcher we use virtual A7 clock rates */
 100         if (is_bL_switching_enabled())
 101                 rate = VIRT_FREQ(cur_cluster, rate);
 102
 103         pr_debug("%s: cpu: %d, cluster: %d, freq: %u\n", __func__, cpu,
 104                         cur_cluster, rate);
 105
 106         return rate;
 107 }
 108
 109 static unsigned int bL_cpufreq_get_rate(unsigned int cpu)
 110 {
 111         if (is_bL_switching_enabled()) {
 112                 pr_debug("%s: freq: %d\n", __func__, per_cpu(cpu_last_req_freq,
 113                                         cpu));
 114
 115                 return per_cpu(cpu_last_req_freq, cpu);
 116         } else {
 117                 return clk_get_cpu_rate(cpu);
 118         }
 119 }
 120
 121 static unsigned int
 122 bL_cpufreq_set_rate(u32 cpu, u32 old_cluster, u32 new_cluster, u32 rate)
 123 {
 124         u32 new_rate, prev_rate;
 125         int ret;
 126         bool bLs = is_bL_switching_enabled();
 127
 128         mutex_lock(&cluster_lock[new_cluster]);
 129
 130         if (bLs) {
 131                 prev_rate = per_cpu(cpu_last_req_freq, cpu);
 132                 per_cpu(cpu_last_req_freq, cpu) = rate;
 133                 per_cpu(physical_cluster, cpu) = new_cluster;
 134
 135                 new_rate = find_cluster_maxfreq(new_cluster);
 136                 new_rate = ACTUAL_FREQ(new_cluster, new_rate);
 137         } else {
 138                 new_rate = rate;
 139         }
 140
 141         pr_debug("%s: cpu: %d, old cluster: %d, new cluster: %d, freq: %d\n",
 142                         __func__, cpu, old_cluster, new_cluster, new_rate);
 143
 144         ret = clk_set_rate(clk[new_cluster], new_rate * 1000);
 145         if (WARN_ON(ret)) {
 146                 pr_err("clk_set_rate failed: %d, new cluster: %d\n", ret,
 147                                 new_cluster);
 148                 if (bLs) {
 149                         per_cpu(cpu_last_req_freq, cpu) = prev_rate;
 150                         per_cpu(physical_cluster, cpu) = old_cluster;
 151                 }
 152
 153                 mutex_unlock(&cluster_lock[new_cluster]);
 154
 155                 return ret;
 156         }
 157
 158         mutex_unlock(&cluster_lock[new_cluster]);
 159
 160         /* Recalc freq for old cluster when switching clusters */
 161         if (old_cluster != new_cluster) {
 162                 pr_debug("%s: cpu: %d, old cluster: %d, new cluster: %d\n",
 163                                 __func__, cpu, old_cluster, new_cluster);
 164
 165                 /* Switch cluster */
 166                 bL_switch_request(cpu, new_cluster);
 167
 168                 mutex_lock(&cluster_lock[old_cluster]);
 169
 170                 /* Set freq of old cluster if there are cpus left on it */
 171                 new_rate = find_cluster_maxfreq(old_cluster);
 172                 new_rate = ACTUAL_FREQ(old_cluster, new_rate);
 173
 174                 if (new_rate) {
 175                         pr_debug("%s: Updating rate of old cluster: %d, to freq: %d\n",
 176                                         __func__, old_cluster, new_rate);
 177
 178                         if (clk_set_rate(clk[old_cluster], new_rate * 1000))
 179                                 pr_err("%s: clk_set_rate failed: %d, old cluster: %d\n",
 180                                                 __func__, ret, old_cluster);
 181                 }
 182                 mutex_unlock(&cluster_lock[old_cluster]);
 183         }
 184
 185         return 0;
 186 }
 187
 188 /* Set clock frequency */
 189 static int bL_cpufreq_set_target(struct cpufreq_policy *policy,
 190                 unsigned int index)
 191 {
 192         struct cpufreq_freqs freqs;
 193         u32 cpu = policy->cpu, cur_cluster, new_cluster, actual_cluster;
 194         int ret = 0;
 195
 196         cur_cluster = cpu_to_cluster(cpu);
 197         new_cluster = actual_cluster = per_cpu(physical_cluster, cpu);
 198
 199         freqs.old = bL_cpufreq_get_rate(cpu);
 200         freqs.new = freq_table[cur_cluster][index].frequency;
 201
 202         pr_debug("%s: cpu: %d, cluster: %d, oldfreq: %d, target freq: %d, new freq: %d\n",
 203                         __func__, cpu, cur_cluster, freqs.old, freqs.new,
 204                         freqs.new);
 205
 206         if (is_bL_switching_enabled()) {
 207                 if ((actual_cluster == A15_CLUSTER) &&
 208                                 (freqs.new < clk_big_min)) {
 209                         new_cluster = A7_CLUSTER;
 210                 } else if ((actual_cluster == A7_CLUSTER) &&
 211                                 (freqs.new > clk_little_max)) {
 212                         new_cluster = A15_CLUSTER;
 213                 }
 214         }
 215
 216         cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE);
 217
 218         ret = bL_cpufreq_set_rate(cpu, actual_cluster, new_cluster, freqs.new);
 219         if (ret)
 220                 freqs.new = freqs.old;
 221
 222         cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);
 223
 224         return ret;
 225 }
 226
 227 static inline u32 get_table_count(struct cpufreq_frequency_table *table)
 228 {
 229         int count;
 230
 231         for (count = 0; table[count].frequency != CPUFREQ_TABLE_END; count++)
 232                 ;
 233
 234         return count;
 235 }
 236
 237 /* get the minimum frequency in the cpufreq_frequency_table */
 238 static inline u32 get_table_min(struct cpufreq_frequency_table *table)
 239 {
 240         int i;
 241         uint32_t min_freq = ~0;
 242         for (i = 0; (table[i].frequency != CPUFREQ_TABLE_END); i++)
 243                 if (table[i].frequency < min_freq)
 244                         min_freq = table[i].frequency;
 245         return min_freq;
 246 }
 247
 248 /* get the maximum frequency in the cpufreq_frequency_table */
 249 static inline u32 get_table_max(struct cpufreq_frequency_table *table)
 250 {
 251         int i;
 252         uint32_t max_freq = 0;
 253         for (i = 0; (table[i].frequency != CPUFREQ_TABLE_END); i++)
 254                 if (table[i].frequency > max_freq)
 255                         max_freq = table[i].frequency;
 256         return max_freq;
 257 }
 258
 259 static int merge_cluster_tables(void)
 260 {
 261         int i, j, k = 0, count = 1;
 262         struct cpufreq_frequency_table *table;
 263
 264         for (i = 0; i < MAX_CLUSTERS; i++)
 265                 count += get_table_count(freq_table[i]);
 266
 267         table = kzalloc(sizeof(*table) * count, GFP_KERNEL);
 268         if (!table)
 269                 return -ENOMEM;
 270
 271         freq_table[MAX_CLUSTERS] = table;
 272
 273         /* Add in reverse order to get freqs in increasing order */
 274         for (i = MAX_CLUSTERS - 1; i >= 0; i--) {
 275                 for (j = 0; freq_table[i][j].frequency != CPUFREQ_TABLE_END;
 276                                 j++) {
 277                         table[k].frequency = VIRT_FREQ(i,
 278                                         freq_table[i][j].frequency);
 279                         pr_debug("%s: index: %d, freq: %d\n", __func__, k,
 280                                         table[k].frequency);
 281                         k++;
 282                 }
 283         }
 284
 285         table[k].driver_data = k;
 286         table[k].frequency = CPUFREQ_TABLE_END;
 287
 288         pr_debug("%s: End, table: %p, count: %d\n", __func__, table, k);
 289
 290         return 0;
 291 }
 292
 293 static void _put_cluster_clk_and_freq_table(struct device *cpu_dev)
 294 {
 295         u32 cluster = raw_cpu_to_cluster(cpu_dev->id);
 296
 297         if (!freq_table[cluster])
 298                 return;
 299
 300         clk_put(clk[cluster]);
 301         dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table[cluster]);
 302         dev_dbg(cpu_dev, "%s: cluster: %d\n", __func__, cluster);
 303 }
 304
 305 static void put_cluster_clk_and_freq_table(struct device *cpu_dev)
 306 {
 307         u32 cluster = cpu_to_cluster(cpu_dev->id);
 308         int i;
 309
 310         if (atomic_dec_return(&cluster_usage[cluster]))
 311                 return;
 312
 313         if (cluster < MAX_CLUSTERS)
 314                 return _put_cluster_clk_and_freq_table(cpu_dev);
 315
 316         for_each_present_cpu(i) {
 317                 struct device *cdev = get_cpu_device(i);
 318                 if (!cdev) {
 319                         pr_err("%s: failed to get cpu%d device\n", __func__, i);
 320                         return;
 321                 }
 322
 323                 _put_cluster_clk_and_freq_table(cdev);
 324         }
 325
 326         /* free virtual table */
 327         kfree(freq_table[cluster]);
 328 }
 329
 330 static int _get_cluster_clk_and_freq_table(struct device *cpu_dev)
 331 {
 332         u32 cluster = raw_cpu_to_cluster(cpu_dev->id);
 333         char name[14] = "cpu-cluster.";
 334         int ret;
 335
 336         if (freq_table[cluster])
 337                 return 0;
 338
 339         ret = arm_bL_ops->init_opp_table(cpu_dev);
 340         if (ret) {
 341                 dev_err(cpu_dev, "%s: init_opp_table failed, cpu: %d, err: %d\n",
 342                                 __func__, cpu_dev->id, ret);
 343                 goto out;
 344         }
 345
 346         ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table[cluster]);
 347         if (ret) {
 348                 dev_err(cpu_dev, "%s: failed to init cpufreq table, cpu: %d, err: %d\n",
 349                                 __func__, cpu_dev->id, ret);
 350                 goto out;
 351         }
 352
 353         name[12] = cluster + '0';
 354         clk[cluster] = clk_get(cpu_dev, name);
 355         if (!IS_ERR(clk[cluster])) {
 356                 dev_dbg(cpu_dev, "%s: clk: %p & freq table: %p, cluster: %d\n",
 357                                 __func__, clk[cluster], freq_table[cluster],
 358                                 cluster);
 359                 return 0;
 360         }
 361
 362         dev_err(cpu_dev, "%s: Failed to get clk for cpu: %d, cluster: %d\n",
 363                         __func__, cpu_dev->id, cluster);
 364         ret = PTR_ERR(clk[cluster]);
 365         dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table[cluster]);
 366
 367 out:
 368         dev_err(cpu_dev, "%s: Failed to get data for cluster: %d\n", __func__,
 369                         cluster);
 370         return ret;
 371 }
 372
 373 static int get_cluster_clk_and_freq_table(struct device *cpu_dev)
 374 {
 375         u32 cluster = cpu_to_cluster(cpu_dev->id);
 376         int i, ret;
 377
 378         if (atomic_inc_return(&cluster_usage[cluster]) != 1)
 379                 return 0;
 380
 381         if (cluster < MAX_CLUSTERS) {
 382                 ret = _get_cluster_clk_and_freq_table(cpu_dev);
 383                 if (ret)
 384                         atomic_dec(&cluster_usage[cluster]);
 385                 return ret;
 386         }
 387
 388         /*
 389          * Get data for all clusters and fill virtual cluster with a merge of
 390          * both
 391          */
 392         for_each_present_cpu(i) {
 393                 struct device *cdev = get_cpu_device(i);
 394                 if (!cdev) {
 395                         pr_err("%s: failed to get cpu%d device\n", __func__, i);
 396                         return -ENODEV;
 397                 }
 398
 399                 ret = _get_cluster_clk_and_freq_table(cdev);
 400                 if (ret)
 401                         goto put_clusters;
 402         }
 403
 404         ret = merge_cluster_tables();
 405         if (ret)
 406                 goto put_clusters;
 407
 408         /* Assuming 2 cluster, set clk_big_min and clk_little_max */
 409         clk_big_min = get_table_min(freq_table[0]);
 410         clk_little_max = VIRT_FREQ(1, get_table_max(freq_table[1]));
 411
 412         pr_debug("%s: cluster: %d, clk_big_min: %d, clk_little_max: %d\n",
 413                         __func__, cluster, clk_big_min, clk_little_max);
 414
 415         return 0;
 416
 417 put_clusters:
 418         for_each_present_cpu(i) {
 419                 struct device *cdev = get_cpu_device(i);
 420                 if (!cdev) {
 421                         pr_err("%s: failed to get cpu%d device\n", __func__, i);
 422                         return -ENODEV;
 423                 }
 424
 425                 _put_cluster_clk_and_freq_table(cdev);
 426         }
 427
 428         atomic_dec(&cluster_usage[cluster]);
 429
 430         return ret;
 431 }
 432
 433 /* Per-CPU initialization */
 434 static int bL_cpufreq_init(struct cpufreq_policy *policy)
 435 {
 436         u32 cur_cluster = cpu_to_cluster(policy->cpu);
 437         struct device *cpu_dev;
 438         int ret;
 439
 440         cpu_dev = get_cpu_device(policy->cpu);
 441         if (!cpu_dev) {
 442                 pr_err("%s: failed to get cpu%d device\n", __func__,
 443                                 policy->cpu);
 444                 return -ENODEV;
 445         }
 446
 447         ret = get_cluster_clk_and_freq_table(cpu_dev);
 448         if (ret)
 449                 return ret;
 450
 451         ret = cpufreq_table_validate_and_show(policy, freq_table[cur_cluster]);
 452         if (ret) {
 453                 dev_err(cpu_dev, "CPU %d, cluster: %d invalid freq table\n",
 454                                 policy->cpu, cur_cluster);
 455                 put_cluster_clk_and_freq_table(cpu_dev);
 456                 return ret;
 457         }
 458
 459         if (cur_cluster < MAX_CLUSTERS) {
 460                 cpumask_copy(policy->cpus, topology_core_cpumask(policy->cpu));
 461
 462                 per_cpu(physical_cluster, policy->cpu) = cur_cluster;
 463         } else {
 464                 /* Assumption: during init, we are always running on A15 */
 465                 per_cpu(physical_cluster, policy->cpu) = A15_CLUSTER;
 466         }
 467
 468         if (arm_bL_ops->get_transition_latency)
 469                 policy->cpuinfo.transition_latency =
 470                         arm_bL_ops->get_transition_latency(cpu_dev);
 471         else
 472                 policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
 473
 474         if (is_bL_switching_enabled())
 475                 per_cpu(cpu_last_req_freq, policy->cpu) = clk_get_cpu_rate(policy->cpu);
 476
 477         dev_info(cpu_dev, "%s: CPU %d initialized\n", __func__, policy->cpu);
 478         return 0;
 479 }
 480
 481 static int bL_cpufreq_exit(struct cpufreq_policy *policy)
 482 {
 483         struct device *cpu_dev;
 484
 485         cpu_dev = get_cpu_device(policy->cpu);
 486         if (!cpu_dev) {
 487                 pr_err("%s: failed to get cpu%d device\n", __func__,
 488                                 policy->cpu);
 489                 return -ENODEV;
 490         }
 491
 492         cpufreq_frequency_table_put_attr(policy->cpu);
 493         put_cluster_clk_and_freq_table(cpu_dev);
 494         dev_dbg(cpu_dev, "%s: Exited, cpu: %d\n", __func__, policy->cpu);
 495
 496         return 0;
 497 }
 498
 499 static struct cpufreq_driver bL_cpufreq_driver = {
 500         .name                   = "arm-big-little",
 501         .flags                  = CPUFREQ_STICKY |
 502                                         CPUFREQ_HAVE_GOVERNOR_PER_POLICY,
 503         .verify                 = cpufreq_generic_frequency_table_verify,
 504         .target_index           = bL_cpufreq_set_target,
 505         .get                    = bL_cpufreq_get_rate,
 506         .init                   = bL_cpufreq_init,
 507         .exit                   = bL_cpufreq_exit,
 508         .attr                   = cpufreq_generic_attr,
 509 };
 510
 511 int bL_cpufreq_register(struct cpufreq_arm_bL_ops *ops)
 512 {
 513         int ret, i;
 514
 515         if (arm_bL_ops) {
 516                 pr_debug("%s: Already registered: %s, exiting\n", __func__,
 517                                 arm_bL_ops->name);
 518                 return -EBUSY;
 519         }
 520
 521         if (!ops || !strlen(ops->name) || !ops->init_opp_table) {
 522                 pr_err("%s: Invalid arm_bL_ops, exiting\n", __func__);
 523                 return -ENODEV;
 524         }
 525
 526         arm_bL_ops = ops;
 527
 528         for (i = 0; i < MAX_CLUSTERS; i++)
 529                 mutex_init(&cluster_lock[i]);
 530
 531         ret = cpufreq_register_driver(&bL_cpufreq_driver);
 532         if (ret) {
 533                 pr_info("%s: Failed registering platform driver: %s, err: %d\n",
 534                                 __func__, ops->name, ret);
 535                 arm_bL_ops = NULL;
 536         } else {
 537                 pr_info("%s: Registered platform driver: %s\n", __func__,
 538                                 ops->name);
 539         }
 540
 541         return ret;
 542 }
 543 EXPORT_SYMBOL_GPL(bL_cpufreq_register);
 544
 545 void bL_cpufreq_unregister(struct cpufreq_arm_bL_ops *ops)
 546 {
 547         if (arm_bL_ops != ops) {
 548                 pr_err("%s: Registered with: %s, can't unregister, exiting\n",
 549                                 __func__, arm_bL_ops->name);
 550                 return;
 551         }
 552
 553         cpufreq_unregister_driver(&bL_cpufreq_driver);
 554         pr_info("%s: Un-registered platform driver: %s\n", __func__,
 555                         arm_bL_ops->name);
 556         arm_bL_ops = NULL;
 557 }
 558 EXPORT_SYMBOL_GPL(bL_cpufreq_unregister);