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1// SPDX-License-Identifier: GPL-2.02/*3 * Versatile Express SPC CPUFreq Interface driver4 *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 ": " fmt13 14#include <linux/clk.h>15#include <linux/cpu.h>16#include <linux/cpufreq.h>17#include <linux/cpumask.h>18#include <linux/device.h>19#include <linux/module.h>20#include <linux/mutex.h>21#include <linux/platform_device.h>22#include <linux/pm_opp.h>23#include <linux/slab.h>24#include <linux/topology.h>25#include <linux/types.h>26 27/* Currently we support only two clusters */28#define A15_CLUSTER 029#define A7_CLUSTER 130#define MAX_CLUSTERS 231 32#ifdef CONFIG_BL_SWITCHER33#include <asm/bL_switcher.h>34static bool bL_switching_enabled;35#define is_bL_switching_enabled() bL_switching_enabled36#define set_switching_enabled(x) (bL_switching_enabled = (x))37#else38#define is_bL_switching_enabled() false39#define set_switching_enabled(x) do { } while (0)40#define bL_switch_request(...) do { } while (0)41#define bL_switcher_put_enabled() do { } while (0)42#define bL_switcher_get_enabled() do { } while (0)43#endif44 45#define ACTUAL_FREQ(cluster, freq) ((cluster == A7_CLUSTER) ? freq << 1 : freq)46#define VIRT_FREQ(cluster, freq) ((cluster == A7_CLUSTER) ? freq >> 1 : freq)47 48static struct clk *clk[MAX_CLUSTERS];49static struct cpufreq_frequency_table *freq_table[MAX_CLUSTERS + 1];50static atomic_t cluster_usage[MAX_CLUSTERS + 1];51 52static unsigned int clk_big_min; /* (Big) clock frequencies */53static unsigned int clk_little_max; /* Maximum clock frequency (Little) */54 55static DEFINE_PER_CPU(unsigned int, physical_cluster);56static DEFINE_PER_CPU(unsigned int, cpu_last_req_freq);57 58static struct mutex cluster_lock[MAX_CLUSTERS];59 60static inline int raw_cpu_to_cluster(int cpu)61{62 return topology_physical_package_id(cpu);63}64 65static inline int cpu_to_cluster(int cpu)66{67 return is_bL_switching_enabled() ?68 MAX_CLUSTERS : raw_cpu_to_cluster(cpu);69}70 71static unsigned int find_cluster_maxfreq(int cluster)72{73 int j;74 u32 max_freq = 0, cpu_freq;75 76 for_each_online_cpu(j) {77 cpu_freq = per_cpu(cpu_last_req_freq, j);78 79 if (cluster == per_cpu(physical_cluster, j) &&80 max_freq < cpu_freq)81 max_freq = cpu_freq;82 }83 84 return max_freq;85}86 87static unsigned int clk_get_cpu_rate(unsigned int cpu)88{89 u32 cur_cluster = per_cpu(physical_cluster, cpu);90 u32 rate = clk_get_rate(clk[cur_cluster]) / 1000;91 92 /* For switcher we use virtual A7 clock rates */93 if (is_bL_switching_enabled())94 rate = VIRT_FREQ(cur_cluster, rate);95 96 return rate;97}98 99static unsigned int ve_spc_cpufreq_get_rate(unsigned int cpu)100{101 if (is_bL_switching_enabled())102 return per_cpu(cpu_last_req_freq, cpu);103 else104 return clk_get_cpu_rate(cpu);105}106 107static unsigned int108ve_spc_cpufreq_set_rate(u32 cpu, u32 old_cluster, u32 new_cluster, u32 rate)109{110 u32 new_rate, prev_rate;111 int ret;112 bool bLs = is_bL_switching_enabled();113 114 mutex_lock(&cluster_lock[new_cluster]);115 116 if (bLs) {117 prev_rate = per_cpu(cpu_last_req_freq, cpu);118 per_cpu(cpu_last_req_freq, cpu) = rate;119 per_cpu(physical_cluster, cpu) = new_cluster;120 121 new_rate = find_cluster_maxfreq(new_cluster);122 new_rate = ACTUAL_FREQ(new_cluster, new_rate);123 } else {124 new_rate = rate;125 }126 127 ret = clk_set_rate(clk[new_cluster], new_rate * 1000);128 if (!ret) {129 /*130 * FIXME: clk_set_rate hasn't returned an error here however it131 * may be that clk_change_rate failed due to hardware or132 * firmware issues and wasn't able to report that due to the133 * current design of the clk core layer. To work around this134 * problem we will read back the clock rate and check it is135 * correct. This needs to be removed once clk core is fixed.136 */137 if (clk_get_rate(clk[new_cluster]) != new_rate * 1000)138 ret = -EIO;139 }140 141 if (WARN_ON(ret)) {142 if (bLs) {143 per_cpu(cpu_last_req_freq, cpu) = prev_rate;144 per_cpu(physical_cluster, cpu) = old_cluster;145 }146 147 mutex_unlock(&cluster_lock[new_cluster]);148 149 return ret;150 }151 152 mutex_unlock(&cluster_lock[new_cluster]);153 154 /* Recalc freq for old cluster when switching clusters */155 if (old_cluster != new_cluster) {156 /* Switch cluster */157 bL_switch_request(cpu, new_cluster);158 159 mutex_lock(&cluster_lock[old_cluster]);160 161 /* Set freq of old cluster if there are cpus left on it */162 new_rate = find_cluster_maxfreq(old_cluster);163 new_rate = ACTUAL_FREQ(old_cluster, new_rate);164 165 if (new_rate &&166 clk_set_rate(clk[old_cluster], new_rate * 1000)) {167 pr_err("%s: clk_set_rate failed: %d, old cluster: %d\n",168 __func__, ret, old_cluster);169 }170 mutex_unlock(&cluster_lock[old_cluster]);171 }172 173 return 0;174}175 176/* Set clock frequency */177static int ve_spc_cpufreq_set_target(struct cpufreq_policy *policy,178 unsigned int index)179{180 u32 cpu = policy->cpu, cur_cluster, new_cluster, actual_cluster;181 unsigned int freqs_new;182 183 cur_cluster = cpu_to_cluster(cpu);184 new_cluster = actual_cluster = per_cpu(physical_cluster, cpu);185 186 freqs_new = freq_table[cur_cluster][index].frequency;187 188 if (is_bL_switching_enabled()) {189 if (actual_cluster == A15_CLUSTER && freqs_new < clk_big_min)190 new_cluster = A7_CLUSTER;191 else if (actual_cluster == A7_CLUSTER &&192 freqs_new > clk_little_max)193 new_cluster = A15_CLUSTER;194 }195 196 return ve_spc_cpufreq_set_rate(cpu, actual_cluster, new_cluster,197 freqs_new);198}199 200static inline u32 get_table_count(struct cpufreq_frequency_table *table)201{202 int count;203 204 for (count = 0; table[count].frequency != CPUFREQ_TABLE_END; count++)205 ;206 207 return count;208}209 210/* get the minimum frequency in the cpufreq_frequency_table */211static inline u32 get_table_min(struct cpufreq_frequency_table *table)212{213 struct cpufreq_frequency_table *pos;214 u32 min_freq = ~0;215 216 cpufreq_for_each_entry(pos, table)217 if (pos->frequency < min_freq)218 min_freq = pos->frequency;219 return min_freq;220}221 222/* get the maximum frequency in the cpufreq_frequency_table */223static inline u32 get_table_max(struct cpufreq_frequency_table *table)224{225 struct cpufreq_frequency_table *pos;226 u32 max_freq = 0;227 228 cpufreq_for_each_entry(pos, table)229 if (pos->frequency > max_freq)230 max_freq = pos->frequency;231 return max_freq;232}233 234static bool search_frequency(struct cpufreq_frequency_table *table, int size,235 unsigned int freq)236{237 int count;238 239 for (count = 0; count < size; count++) {240 if (table[count].frequency == freq)241 return true;242 }243 244 return false;245}246 247static int merge_cluster_tables(void)248{249 int i, j, k = 0, count = 1;250 struct cpufreq_frequency_table *table;251 252 for (i = 0; i < MAX_CLUSTERS; i++)253 count += get_table_count(freq_table[i]);254 255 table = kcalloc(count, sizeof(*table), GFP_KERNEL);256 if (!table)257 return -ENOMEM;258 259 freq_table[MAX_CLUSTERS] = table;260 261 /* Add in reverse order to get freqs in increasing order */262 for (i = MAX_CLUSTERS - 1; i >= 0; i--, count = k) {263 for (j = 0; freq_table[i][j].frequency != CPUFREQ_TABLE_END;264 j++) {265 if (i == A15_CLUSTER &&266 search_frequency(table, count, freq_table[i][j].frequency))267 continue; /* skip duplicates */268 table[k++].frequency =269 VIRT_FREQ(i, freq_table[i][j].frequency);270 }271 }272 273 table[k].driver_data = k;274 table[k].frequency = CPUFREQ_TABLE_END;275 276 return 0;277}278 279static void _put_cluster_clk_and_freq_table(struct device *cpu_dev,280 const struct cpumask *cpumask)281{282 u32 cluster = raw_cpu_to_cluster(cpu_dev->id);283 284 if (!freq_table[cluster])285 return;286 287 clk_put(clk[cluster]);288 dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table[cluster]);289}290 291static void put_cluster_clk_and_freq_table(struct device *cpu_dev,292 const struct cpumask *cpumask)293{294 u32 cluster = cpu_to_cluster(cpu_dev->id);295 int i;296 297 if (atomic_dec_return(&cluster_usage[cluster]))298 return;299 300 if (cluster < MAX_CLUSTERS)301 return _put_cluster_clk_and_freq_table(cpu_dev, cpumask);302 303 for_each_present_cpu(i) {304 struct device *cdev = get_cpu_device(i);305 306 if (!cdev)307 return;308 309 _put_cluster_clk_and_freq_table(cdev, cpumask);310 }311 312 /* free virtual table */313 kfree(freq_table[cluster]);314}315 316static int _get_cluster_clk_and_freq_table(struct device *cpu_dev,317 const struct cpumask *cpumask)318{319 u32 cluster = raw_cpu_to_cluster(cpu_dev->id);320 int ret;321 322 if (freq_table[cluster])323 return 0;324 325 /*326 * platform specific SPC code must initialise the opp table327 * so just check if the OPP count is non-zero328 */329 ret = dev_pm_opp_get_opp_count(cpu_dev) <= 0;330 if (ret)331 goto out;332 333 ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table[cluster]);334 if (ret)335 goto out;336 337 clk[cluster] = clk_get(cpu_dev, NULL);338 if (!IS_ERR(clk[cluster]))339 return 0;340 341 dev_err(cpu_dev, "%s: Failed to get clk for cpu: %d, cluster: %d\n",342 __func__, cpu_dev->id, cluster);343 ret = PTR_ERR(clk[cluster]);344 dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table[cluster]);345 346out:347 dev_err(cpu_dev, "%s: Failed to get data for cluster: %d\n", __func__,348 cluster);349 return ret;350}351 352static int get_cluster_clk_and_freq_table(struct device *cpu_dev,353 const struct cpumask *cpumask)354{355 u32 cluster = cpu_to_cluster(cpu_dev->id);356 int i, ret;357 358 if (atomic_inc_return(&cluster_usage[cluster]) != 1)359 return 0;360 361 if (cluster < MAX_CLUSTERS) {362 ret = _get_cluster_clk_and_freq_table(cpu_dev, cpumask);363 if (ret)364 atomic_dec(&cluster_usage[cluster]);365 return ret;366 }367 368 /*369 * Get data for all clusters and fill virtual cluster with a merge of370 * both371 */372 for_each_present_cpu(i) {373 struct device *cdev = get_cpu_device(i);374 375 if (!cdev)376 return -ENODEV;377 378 ret = _get_cluster_clk_and_freq_table(cdev, cpumask);379 if (ret)380 goto put_clusters;381 }382 383 ret = merge_cluster_tables();384 if (ret)385 goto put_clusters;386 387 /* Assuming 2 cluster, set clk_big_min and clk_little_max */388 clk_big_min = get_table_min(freq_table[A15_CLUSTER]);389 clk_little_max = VIRT_FREQ(A7_CLUSTER,390 get_table_max(freq_table[A7_CLUSTER]));391 392 return 0;393 394put_clusters:395 for_each_present_cpu(i) {396 struct device *cdev = get_cpu_device(i);397 398 if (!cdev)399 return -ENODEV;400 401 _put_cluster_clk_and_freq_table(cdev, cpumask);402 }403 404 atomic_dec(&cluster_usage[cluster]);405 406 return ret;407}408 409/* Per-CPU initialization */410static int ve_spc_cpufreq_init(struct cpufreq_policy *policy)411{412 u32 cur_cluster = cpu_to_cluster(policy->cpu);413 struct device *cpu_dev;414 int ret;415 416 cpu_dev = get_cpu_device(policy->cpu);417 if (!cpu_dev) {418 pr_err("%s: failed to get cpu%d device\n", __func__,419 policy->cpu);420 return -ENODEV;421 }422 423 if (cur_cluster < MAX_CLUSTERS) {424 int cpu;425 426 dev_pm_opp_get_sharing_cpus(cpu_dev, policy->cpus);427 428 for_each_cpu(cpu, policy->cpus)429 per_cpu(physical_cluster, cpu) = cur_cluster;430 } else {431 /* Assumption: during init, we are always running on A15 */432 per_cpu(physical_cluster, policy->cpu) = A15_CLUSTER;433 }434 435 ret = get_cluster_clk_and_freq_table(cpu_dev, policy->cpus);436 if (ret)437 return ret;438 439 policy->freq_table = freq_table[cur_cluster];440 policy->cpuinfo.transition_latency = 1000000; /* 1 ms */441 442 if (is_bL_switching_enabled())443 per_cpu(cpu_last_req_freq, policy->cpu) =444 clk_get_cpu_rate(policy->cpu);445 446 dev_info(cpu_dev, "%s: CPU %d initialized\n", __func__, policy->cpu);447 return 0;448}449 450static void ve_spc_cpufreq_exit(struct cpufreq_policy *policy)451{452 struct device *cpu_dev;453 454 cpu_dev = get_cpu_device(policy->cpu);455 if (!cpu_dev) {456 pr_err("%s: failed to get cpu%d device\n", __func__,457 policy->cpu);458 return;459 }460 461 put_cluster_clk_and_freq_table(cpu_dev, policy->related_cpus);462}463 464static struct cpufreq_driver ve_spc_cpufreq_driver = {465 .name = "vexpress-spc",466 .flags = CPUFREQ_HAVE_GOVERNOR_PER_POLICY |467 CPUFREQ_NEED_INITIAL_FREQ_CHECK,468 .verify = cpufreq_generic_frequency_table_verify,469 .target_index = ve_spc_cpufreq_set_target,470 .get = ve_spc_cpufreq_get_rate,471 .init = ve_spc_cpufreq_init,472 .exit = ve_spc_cpufreq_exit,473 .register_em = cpufreq_register_em_with_opp,474 .attr = cpufreq_generic_attr,475};476 477#ifdef CONFIG_BL_SWITCHER478static int bL_cpufreq_switcher_notifier(struct notifier_block *nfb,479 unsigned long action, void *_arg)480{481 pr_debug("%s: action: %ld\n", __func__, action);482 483 switch (action) {484 case BL_NOTIFY_PRE_ENABLE:485 case BL_NOTIFY_PRE_DISABLE:486 cpufreq_unregister_driver(&ve_spc_cpufreq_driver);487 break;488 489 case BL_NOTIFY_POST_ENABLE:490 set_switching_enabled(true);491 cpufreq_register_driver(&ve_spc_cpufreq_driver);492 break;493 494 case BL_NOTIFY_POST_DISABLE:495 set_switching_enabled(false);496 cpufreq_register_driver(&ve_spc_cpufreq_driver);497 break;498 499 default:500 return NOTIFY_DONE;501 }502 503 return NOTIFY_OK;504}505 506static struct notifier_block bL_switcher_notifier = {507 .notifier_call = bL_cpufreq_switcher_notifier,508};509 510static int __bLs_register_notifier(void)511{512 return bL_switcher_register_notifier(&bL_switcher_notifier);513}514 515static int __bLs_unregister_notifier(void)516{517 return bL_switcher_unregister_notifier(&bL_switcher_notifier);518}519#else520static int __bLs_register_notifier(void) { return 0; }521static int __bLs_unregister_notifier(void) { return 0; }522#endif523 524static int ve_spc_cpufreq_probe(struct platform_device *pdev)525{526 int ret, i;527 528 set_switching_enabled(bL_switcher_get_enabled());529 530 for (i = 0; i < MAX_CLUSTERS; i++)531 mutex_init(&cluster_lock[i]);532 533 if (!is_bL_switching_enabled())534 ve_spc_cpufreq_driver.flags |= CPUFREQ_IS_COOLING_DEV;535 536 ret = cpufreq_register_driver(&ve_spc_cpufreq_driver);537 if (ret) {538 pr_info("%s: Failed registering platform driver: %s, err: %d\n",539 __func__, ve_spc_cpufreq_driver.name, ret);540 } else {541 ret = __bLs_register_notifier();542 if (ret)543 cpufreq_unregister_driver(&ve_spc_cpufreq_driver);544 else545 pr_info("%s: Registered platform driver: %s\n",546 __func__, ve_spc_cpufreq_driver.name);547 }548 549 bL_switcher_put_enabled();550 return ret;551}552 553static void ve_spc_cpufreq_remove(struct platform_device *pdev)554{555 bL_switcher_get_enabled();556 __bLs_unregister_notifier();557 cpufreq_unregister_driver(&ve_spc_cpufreq_driver);558 bL_switcher_put_enabled();559 pr_info("%s: Un-registered platform driver: %s\n", __func__,560 ve_spc_cpufreq_driver.name);561}562 563static struct platform_driver ve_spc_cpufreq_platdrv = {564 .driver = {565 .name = "vexpress-spc-cpufreq",566 },567 .probe = ve_spc_cpufreq_probe,568 .remove_new = ve_spc_cpufreq_remove,569};570module_platform_driver(ve_spc_cpufreq_platdrv);571 572MODULE_ALIAS("platform:vexpress-spc-cpufreq");573MODULE_AUTHOR("Viresh Kumar <viresh.kumar@linaro.org>");574MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>");575MODULE_DESCRIPTION("Vexpress SPC ARM big LITTLE cpufreq driver");576MODULE_LICENSE("GPL v2");577