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/module.h> 28#include <linux/mutex.h> 29#include <linux/of_platform.h> 30#include <linux/pm_opp.h> 31#include <linux/slab.h> 32#include <linux/topology.h> 33#include <linux/types.h> 34#include <asm/bL_switcher.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 44static bool bL_switching_enabled; 45#define is_bL_switching_enabled() bL_switching_enabled 46#define set_switching_enabled(x) (bL_switching_enabled = (x)) 47#else 48#define is_bL_switching_enabled() false 49#define set_switching_enabled(x) do { } while (0) 50#endif 51 52#define ACTUAL_FREQ(cluster, freq) ((cluster == A7_CLUSTER) ? freq << 1 : freq) 53#define VIRT_FREQ(cluster, freq) ((cluster == A7_CLUSTER) ? freq >> 1 : freq) 54 55static struct cpufreq_arm_bL_ops *arm_bL_ops; 56static struct clk *clk[MAX_CLUSTERS]; 57static struct cpufreq_frequency_table *freq_table[MAX_CLUSTERS + 1]; 58static atomic_t cluster_usage[MAX_CLUSTERS + 1]; 59 60static unsigned int clk_big_min; /* (Big) clock frequencies */ 61static unsigned int clk_little_max; /* Maximum clock frequency (Little) */ 62 63static DEFINE_PER_CPU(unsigned int, physical_cluster); 64static DEFINE_PER_CPU(unsigned int, cpu_last_req_freq); 65 66static struct mutex cluster_lock[MAX_CLUSTERS]; 67 68static inline int raw_cpu_to_cluster(int cpu) 69{ 70 return topology_physical_package_id(cpu); 71} 72 73static inline int cpu_to_cluster(int cpu) 74{ 75 return is_bL_switching_enabled() ? 76 MAX_CLUSTERS : raw_cpu_to_cluster(cpu); 77} 78 79static unsigned int find_cluster_maxfreq(int cluster) 80{ 81 int j; 82 u32 max_freq = 0, cpu_freq; 83 84 for_each_online_cpu(j) { 85 cpu_freq = per_cpu(cpu_last_req_freq, j); 86 87 if ((cluster == per_cpu(physical_cluster, j)) && 88 (max_freq < cpu_freq)) 89 max_freq = cpu_freq; 90 } 91 92 pr_debug("%s: cluster: %d, max freq: %d\n", __func__, cluster, 93 max_freq); 94 95 return max_freq; 96} 97 98static unsigned int clk_get_cpu_rate(unsigned int cpu) 99{ 100 u32 cur_cluster = per_cpu(physical_cluster, cpu); 101 u32 rate = clk_get_rate(clk[cur_cluster]) / 1000; 102 103 /* For switcher we use virtual A7 clock rates */ 104 if (is_bL_switching_enabled()) 105 rate = VIRT_FREQ(cur_cluster, rate); 106 107 pr_debug("%s: cpu: %d, cluster: %d, freq: %u\n", __func__, cpu, 108 cur_cluster, rate); 109 110 return rate; 111} 112 113static unsigned int bL_cpufreq_get_rate(unsigned int cpu) 114{ 115 if (is_bL_switching_enabled()) { 116 pr_debug("%s: freq: %d\n", __func__, per_cpu(cpu_last_req_freq, 117 cpu)); 118 119 return per_cpu(cpu_last_req_freq, cpu); 120 } else { 121 return clk_get_cpu_rate(cpu); 122 } 123} 124 125static unsigned int 126bL_cpufreq_set_rate(u32 cpu, u32 old_cluster, u32 new_cluster, u32 rate) 127{ 128 u32 new_rate, prev_rate; 129 int ret; 130 bool bLs = is_bL_switching_enabled(); 131 132 mutex_lock(&cluster_lock[new_cluster]); 133 134 if (bLs) { 135 prev_rate = per_cpu(cpu_last_req_freq, cpu); 136 per_cpu(cpu_last_req_freq, cpu) = rate; 137 per_cpu(physical_cluster, cpu) = new_cluster; 138 139 new_rate = find_cluster_maxfreq(new_cluster); 140 new_rate = ACTUAL_FREQ(new_cluster, new_rate); 141 } else { 142 new_rate = rate; 143 } 144 145 pr_debug("%s: cpu: %d, old cluster: %d, new cluster: %d, freq: %d\n", 146 __func__, cpu, old_cluster, new_cluster, new_rate); 147 148 ret = clk_set_rate(clk[new_cluster], new_rate * 1000); 149 if (WARN_ON(ret)) { 150 pr_err("clk_set_rate failed: %d, new cluster: %d\n", ret, 151 new_cluster); 152 if (bLs) { 153 per_cpu(cpu_last_req_freq, cpu) = prev_rate; 154 per_cpu(physical_cluster, cpu) = old_cluster; 155 } 156 157 mutex_unlock(&cluster_lock[new_cluster]); 158 159 return ret; 160 } 161 162 mutex_unlock(&cluster_lock[new_cluster]); 163 164 /* Recalc freq for old cluster when switching clusters */ 165 if (old_cluster != new_cluster) { 166 pr_debug("%s: cpu: %d, old cluster: %d, new cluster: %d\n", 167 __func__, cpu, old_cluster, new_cluster); 168 169 /* Switch cluster */ 170 bL_switch_request(cpu, new_cluster); 171 172 mutex_lock(&cluster_lock[old_cluster]); 173 174 /* Set freq of old cluster if there are cpus left on it */ 175 new_rate = find_cluster_maxfreq(old_cluster); 176 new_rate = ACTUAL_FREQ(old_cluster, new_rate); 177 178 if (new_rate) { 179 pr_debug("%s: Updating rate of old cluster: %d, to freq: %d\n", 180 __func__, old_cluster, new_rate); 181 182 if (clk_set_rate(clk[old_cluster], new_rate * 1000)) 183 pr_err("%s: clk_set_rate failed: %d, old cluster: %d\n", 184 __func__, ret, old_cluster); 185 } 186 mutex_unlock(&cluster_lock[old_cluster]); 187 } 188 189 return 0; 190} 191 192/* Set clock frequency */ 193static int bL_cpufreq_set_target(struct cpufreq_policy *policy, 194 unsigned int index) 195{ 196 u32 cpu = policy->cpu, cur_cluster, new_cluster, actual_cluster; 197 unsigned int freqs_new; 198 199 cur_cluster = cpu_to_cluster(cpu); 200 new_cluster = actual_cluster = per_cpu(physical_cluster, cpu); 201 202 freqs_new = freq_table[cur_cluster][index].frequency; 203 204 if (is_bL_switching_enabled()) { 205 if ((actual_cluster == A15_CLUSTER) && 206 (freqs_new < clk_big_min)) { 207 new_cluster = A7_CLUSTER; 208 } else if ((actual_cluster == A7_CLUSTER) && 209 (freqs_new > clk_little_max)) { 210 new_cluster = A15_CLUSTER; 211 } 212 } 213 214 return bL_cpufreq_set_rate(cpu, actual_cluster, new_cluster, freqs_new); 215} 216 217static inline u32 get_table_count(struct cpufreq_frequency_table *table) 218{ 219 int count; 220 221 for (count = 0; table[count].frequency != CPUFREQ_TABLE_END; count++) 222 ; 223 224 return count; 225} 226 227/* get the minimum frequency in the cpufreq_frequency_table */ 228static inline u32 get_table_min(struct cpufreq_frequency_table *table) 229{ 230 struct cpufreq_frequency_table *pos; 231 uint32_t min_freq = ~0; 232 cpufreq_for_each_entry(pos, table) 233 if (pos->frequency < min_freq) 234 min_freq = pos->frequency; 235 return min_freq; 236} 237 238/* get the maximum frequency in the cpufreq_frequency_table */ 239static inline u32 get_table_max(struct cpufreq_frequency_table *table) 240{ 241 struct cpufreq_frequency_table *pos; 242 uint32_t max_freq = 0; 243 cpufreq_for_each_entry(pos, table) 244 if (pos->frequency > max_freq) 245 max_freq = pos->frequency; 246 return max_freq; 247} 248 249static int merge_cluster_tables(void) 250{ 251 int i, j, k = 0, count = 1; 252 struct cpufreq_frequency_table *table; 253 254 for (i = 0; i < MAX_CLUSTERS; i++) 255 count += get_table_count(freq_table[i]); 256 257 table = kzalloc(sizeof(*table) * count, GFP_KERNEL); 258 if (!table) 259 return -ENOMEM; 260 261 freq_table[MAX_CLUSTERS] = table; 262 263 /* Add in reverse order to get freqs in increasing order */ 264 for (i = MAX_CLUSTERS - 1; i >= 0; i--) { 265 for (j = 0; freq_table[i][j].frequency != CPUFREQ_TABLE_END; 266 j++) { 267 table[k].frequency = VIRT_FREQ(i, 268 freq_table[i][j].frequency); 269 pr_debug("%s: index: %d, freq: %d\n", __func__, k, 270 table[k].frequency); 271 k++; 272 } 273 } 274 275 table[k].driver_data = k; 276 table[k].frequency = CPUFREQ_TABLE_END; 277 278 pr_debug("%s: End, table: %p, count: %d\n", __func__, table, k); 279 280 return 0; 281} 282 283static void _put_cluster_clk_and_freq_table(struct device *cpu_dev) 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 if (arm_bL_ops->free_opp_table) 293 arm_bL_ops->free_opp_table(cpu_dev); 294 dev_dbg(cpu_dev, "%s: cluster: %d\n", __func__, cluster); 295} 296 297static void put_cluster_clk_and_freq_table(struct device *cpu_dev) 298{ 299 u32 cluster = cpu_to_cluster(cpu_dev->id); 300 int i; 301 302 if (atomic_dec_return(&cluster_usage[cluster])) 303 return; 304 305 if (cluster < MAX_CLUSTERS) 306 return _put_cluster_clk_and_freq_table(cpu_dev); 307 308 for_each_present_cpu(i) { 309 struct device *cdev = get_cpu_device(i); 310 if (!cdev) { 311 pr_err("%s: failed to get cpu%d device\n", __func__, i); 312 return; 313 } 314 315 _put_cluster_clk_and_freq_table(cdev); 316 } 317 318 /* free virtual table */ 319 kfree(freq_table[cluster]); 320} 321 322static int _get_cluster_clk_and_freq_table(struct device *cpu_dev) 323{ 324 u32 cluster = raw_cpu_to_cluster(cpu_dev->id); 325 char name[14] = "cpu-cluster."; 326 int ret; 327 328 if (freq_table[cluster]) 329 return 0; 330 331 ret = arm_bL_ops->init_opp_table(cpu_dev); 332 if (ret) { 333 dev_err(cpu_dev, "%s: init_opp_table failed, cpu: %d, err: %d\n", 334 __func__, cpu_dev->id, ret); 335 goto out; 336 } 337 338 ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table[cluster]); 339 if (ret) { 340 dev_err(cpu_dev, "%s: failed to init cpufreq table, cpu: %d, err: %d\n", 341 __func__, cpu_dev->id, ret); 342 goto free_opp_table; 343 } 344 345 name[12] = cluster + '0'; 346 clk[cluster] = clk_get(cpu_dev, name); 347 if (!IS_ERR(clk[cluster])) { 348 dev_dbg(cpu_dev, "%s: clk: %p & freq table: %p, cluster: %d\n", 349 __func__, clk[cluster], freq_table[cluster], 350 cluster); 351 return 0; 352 } 353 354 dev_err(cpu_dev, "%s: Failed to get clk for cpu: %d, cluster: %d\n", 355 __func__, cpu_dev->id, cluster); 356 ret = PTR_ERR(clk[cluster]); 357 dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table[cluster]); 358 359free_opp_table: 360 if (arm_bL_ops->free_opp_table) 361 arm_bL_ops->free_opp_table(cpu_dev); 362out: 363 dev_err(cpu_dev, "%s: Failed to get data for cluster: %d\n", __func__, 364 cluster); 365 return ret; 366} 367 368static int get_cluster_clk_and_freq_table(struct device *cpu_dev) 369{ 370 u32 cluster = cpu_to_cluster(cpu_dev->id); 371 int i, ret; 372 373 if (atomic_inc_return(&cluster_usage[cluster]) != 1) 374 return 0; 375 376 if (cluster < MAX_CLUSTERS) { 377 ret = _get_cluster_clk_and_freq_table(cpu_dev); 378 if (ret) 379 atomic_dec(&cluster_usage[cluster]); 380 return ret; 381 } 382 383 /* 384 * Get data for all clusters and fill virtual cluster with a merge of 385 * both 386 */ 387 for_each_present_cpu(i) { 388 struct device *cdev = get_cpu_device(i); 389 if (!cdev) { 390 pr_err("%s: failed to get cpu%d device\n", __func__, i); 391 return -ENODEV; 392 } 393 394 ret = _get_cluster_clk_and_freq_table(cdev); 395 if (ret) 396 goto put_clusters; 397 } 398 399 ret = merge_cluster_tables(); 400 if (ret) 401 goto put_clusters; 402 403 /* Assuming 2 cluster, set clk_big_min and clk_little_max */ 404 clk_big_min = get_table_min(freq_table[0]); 405 clk_little_max = VIRT_FREQ(1, get_table_max(freq_table[1])); 406 407 pr_debug("%s: cluster: %d, clk_big_min: %d, clk_little_max: %d\n", 408 __func__, cluster, clk_big_min, clk_little_max); 409 410 return 0; 411 412put_clusters: 413 for_each_present_cpu(i) { 414 struct device *cdev = get_cpu_device(i); 415 if (!cdev) { 416 pr_err("%s: failed to get cpu%d device\n", __func__, i); 417 return -ENODEV; 418 } 419 420 _put_cluster_clk_and_freq_table(cdev); 421 } 422 423 atomic_dec(&cluster_usage[cluster]); 424 425 return ret; 426} 427 428/* Per-CPU initialization */ 429static int bL_cpufreq_init(struct cpufreq_policy *policy) 430{ 431 u32 cur_cluster = cpu_to_cluster(policy->cpu); 432 struct device *cpu_dev; 433 int ret; 434 435 cpu_dev = get_cpu_device(policy->cpu); 436 if (!cpu_dev) { 437 pr_err("%s: failed to get cpu%d device\n", __func__, 438 policy->cpu); 439 return -ENODEV; 440 } 441 442 ret = get_cluster_clk_and_freq_table(cpu_dev); 443 if (ret) 444 return ret; 445 446 ret = cpufreq_table_validate_and_show(policy, freq_table[cur_cluster]); 447 if (ret) { 448 dev_err(cpu_dev, "CPU %d, cluster: %d invalid freq table\n", 449 policy->cpu, cur_cluster); 450 put_cluster_clk_and_freq_table(cpu_dev); 451 return ret; 452 } 453 454 if (cur_cluster < MAX_CLUSTERS) { 455 int cpu; 456 457 cpumask_copy(policy->cpus, topology_core_cpumask(policy->cpu)); 458 459 for_each_cpu(cpu, policy->cpus) 460 per_cpu(physical_cluster, cpu) = cur_cluster; 461 } else { 462 /* Assumption: during init, we are always running on A15 */ 463 per_cpu(physical_cluster, policy->cpu) = A15_CLUSTER; 464 } 465 466 if (arm_bL_ops->get_transition_latency) 467 policy->cpuinfo.transition_latency = 468 arm_bL_ops->get_transition_latency(cpu_dev); 469 else 470 policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL; 471 472 if (is_bL_switching_enabled()) 473 per_cpu(cpu_last_req_freq, policy->cpu) = clk_get_cpu_rate(policy->cpu); 474 475 dev_info(cpu_dev, "%s: CPU %d initialized\n", __func__, policy->cpu); 476 return 0; 477} 478 479static int bL_cpufreq_exit(struct cpufreq_policy *policy) 480{ 481 struct device *cpu_dev; 482 483 cpu_dev = get_cpu_device(policy->cpu); 484 if (!cpu_dev) { 485 pr_err("%s: failed to get cpu%d device\n", __func__, 486 policy->cpu); 487 return -ENODEV; 488 } 489 490 put_cluster_clk_and_freq_table(cpu_dev); 491 dev_dbg(cpu_dev, "%s: Exited, cpu: %d\n", __func__, policy->cpu); 492 493 return 0; 494} 495 496static struct cpufreq_driver bL_cpufreq_driver = { 497 .name = "arm-big-little", 498 .flags = CPUFREQ_STICKY | 499 CPUFREQ_HAVE_GOVERNOR_PER_POLICY | 500 CPUFREQ_NEED_INITIAL_FREQ_CHECK, 501 .verify = cpufreq_generic_frequency_table_verify, 502 .target_index = bL_cpufreq_set_target, 503 .get = bL_cpufreq_get_rate, 504 .init = bL_cpufreq_init, 505 .exit = bL_cpufreq_exit, 506 .attr = cpufreq_generic_attr, 507}; 508 509static int bL_cpufreq_switcher_notifier(struct notifier_block *nfb, 510 unsigned long action, void *_arg) 511{ 512 pr_debug("%s: action: %ld\n", __func__, action); 513 514 switch (action) { 515 case BL_NOTIFY_PRE_ENABLE: 516 case BL_NOTIFY_PRE_DISABLE: 517 cpufreq_unregister_driver(&bL_cpufreq_driver); 518 break; 519 520 case BL_NOTIFY_POST_ENABLE: 521 set_switching_enabled(true); 522 cpufreq_register_driver(&bL_cpufreq_driver); 523 break; 524 525 case BL_NOTIFY_POST_DISABLE: 526 set_switching_enabled(false); 527 cpufreq_register_driver(&bL_cpufreq_driver); 528 break; 529 530 default: 531 return NOTIFY_DONE; 532 } 533 534 return NOTIFY_OK; 535} 536 537static struct notifier_block bL_switcher_notifier = { 538 .notifier_call = bL_cpufreq_switcher_notifier, 539}; 540 541int bL_cpufreq_register(struct cpufreq_arm_bL_ops *ops) 542{ 543 int ret, i; 544 545 if (arm_bL_ops) { 546 pr_debug("%s: Already registered: %s, exiting\n", __func__, 547 arm_bL_ops->name); 548 return -EBUSY; 549 } 550 551 if (!ops || !strlen(ops->name) || !ops->init_opp_table) { 552 pr_err("%s: Invalid arm_bL_ops, exiting\n", __func__); 553 return -ENODEV; 554 } 555 556 arm_bL_ops = ops; 557 558 ret = bL_switcher_get_enabled(); 559 set_switching_enabled(ret); 560 561 for (i = 0; i < MAX_CLUSTERS; i++) 562 mutex_init(&cluster_lock[i]); 563 564 ret = cpufreq_register_driver(&bL_cpufreq_driver); 565 if (ret) { 566 pr_info("%s: Failed registering platform driver: %s, err: %d\n", 567 __func__, ops->name, ret); 568 arm_bL_ops = NULL; 569 } else { 570 ret = bL_switcher_register_notifier(&bL_switcher_notifier); 571 if (ret) { 572 cpufreq_unregister_driver(&bL_cpufreq_driver); 573 arm_bL_ops = NULL; 574 } else { 575 pr_info("%s: Registered platform driver: %s\n", 576 __func__, ops->name); 577 } 578 } 579 580 bL_switcher_put_enabled(); 581 return ret; 582} 583EXPORT_SYMBOL_GPL(bL_cpufreq_register); 584 585void bL_cpufreq_unregister(struct cpufreq_arm_bL_ops *ops) 586{ 587 if (arm_bL_ops != ops) { 588 pr_err("%s: Registered with: %s, can't unregister, exiting\n", 589 __func__, arm_bL_ops->name); 590 return; 591 } 592 593 bL_switcher_get_enabled(); 594 bL_switcher_unregister_notifier(&bL_switcher_notifier); 595 cpufreq_unregister_driver(&bL_cpufreq_driver); 596 bL_switcher_put_enabled(); 597 pr_info("%s: Un-registered platform driver: %s\n", __func__, 598 arm_bL_ops->name); 599 arm_bL_ops = NULL; 600} 601EXPORT_SYMBOL_GPL(bL_cpufreq_unregister); 602 603MODULE_AUTHOR("Viresh Kumar <viresh.kumar@linaro.org>"); 604MODULE_DESCRIPTION("Generic ARM big LITTLE cpufreq driver"); 605MODULE_LICENSE("GPL v2"); 606