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_STICKY | 490 CPUFREQ_HAVE_GOVERNOR_PER_POLICY | 491 CPUFREQ_NEED_INITIAL_FREQ_CHECK, 492 .verify = cpufreq_generic_frequency_table_verify, 493 .target_index = ve_spc_cpufreq_set_target, 494 .get = ve_spc_cpufreq_get_rate, 495 .init = ve_spc_cpufreq_init, 496 .exit = ve_spc_cpufreq_exit, 497 .ready = ve_spc_cpufreq_ready, 498 .attr = cpufreq_generic_attr, 499}; 500 501#ifdef CONFIG_BL_SWITCHER 502static int bL_cpufreq_switcher_notifier(struct notifier_block *nfb, 503 unsigned long action, void *_arg) 504{ 505 pr_debug("%s: action: %ld\n", __func__, action); 506 507 switch (action) { 508 case BL_NOTIFY_PRE_ENABLE: 509 case BL_NOTIFY_PRE_DISABLE: 510 cpufreq_unregister_driver(&ve_spc_cpufreq_driver); 511 break; 512 513 case BL_NOTIFY_POST_ENABLE: 514 set_switching_enabled(true); 515 cpufreq_register_driver(&ve_spc_cpufreq_driver); 516 break; 517 518 case BL_NOTIFY_POST_DISABLE: 519 set_switching_enabled(false); 520 cpufreq_register_driver(&ve_spc_cpufreq_driver); 521 break; 522 523 default: 524 return NOTIFY_DONE; 525 } 526 527 return NOTIFY_OK; 528} 529 530static struct notifier_block bL_switcher_notifier = { 531 .notifier_call = bL_cpufreq_switcher_notifier, 532}; 533 534static int __bLs_register_notifier(void) 535{ 536 return bL_switcher_register_notifier(&bL_switcher_notifier); 537} 538 539static int __bLs_unregister_notifier(void) 540{ 541 return bL_switcher_unregister_notifier(&bL_switcher_notifier); 542} 543#else 544static int __bLs_register_notifier(void) { return 0; } 545static int __bLs_unregister_notifier(void) { return 0; } 546#endif 547 548static int ve_spc_cpufreq_probe(struct platform_device *pdev) 549{ 550 int ret, i; 551 552 set_switching_enabled(bL_switcher_get_enabled()); 553 554 for (i = 0; i < MAX_CLUSTERS; i++) 555 mutex_init(&cluster_lock[i]); 556 557 ret = cpufreq_register_driver(&ve_spc_cpufreq_driver); 558 if (ret) { 559 pr_info("%s: Failed registering platform driver: %s, err: %d\n", 560 __func__, ve_spc_cpufreq_driver.name, ret); 561 } else { 562 ret = __bLs_register_notifier(); 563 if (ret) 564 cpufreq_unregister_driver(&ve_spc_cpufreq_driver); 565 else 566 pr_info("%s: Registered platform driver: %s\n", 567 __func__, ve_spc_cpufreq_driver.name); 568 } 569 570 bL_switcher_put_enabled(); 571 return ret; 572} 573 574static int ve_spc_cpufreq_remove(struct platform_device *pdev) 575{ 576 bL_switcher_get_enabled(); 577 __bLs_unregister_notifier(); 578 cpufreq_unregister_driver(&ve_spc_cpufreq_driver); 579 bL_switcher_put_enabled(); 580 pr_info("%s: Un-registered platform driver: %s\n", __func__, 581 ve_spc_cpufreq_driver.name); 582 return 0; 583} 584 585static struct platform_driver ve_spc_cpufreq_platdrv = { 586 .driver = { 587 .name = "vexpress-spc-cpufreq", 588 }, 589 .probe = ve_spc_cpufreq_probe, 590 .remove = ve_spc_cpufreq_remove, 591}; 592module_platform_driver(ve_spc_cpufreq_platdrv); 593 594MODULE_ALIAS("platform:vexpress-spc-cpufreq"); 595MODULE_AUTHOR("Viresh Kumar <viresh.kumar@linaro.org>"); 596MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>"); 597MODULE_DESCRIPTION("Vexpress SPC ARM big LITTLE cpufreq driver"); 598MODULE_LICENSE("GPL v2"); 599