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/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 0 29 #define A7_CLUSTER 1 30 #define MAX_CLUSTERS 2 31 32 #ifdef CONFIG_BL_SWITCHER 33 #include <asm/bL_switcher.h> 34 static bool bL_switching_enabled; 35 #define is_bL_switching_enabled() bL_switching_enabled 36 #define set_switching_enabled(x) (bL_switching_enabled = (x)) 37 #else 38 #define is_bL_switching_enabled() false 39 #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 #endif 44 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 48 static struct clk *clk[MAX_CLUSTERS]; 49 static struct cpufreq_frequency_table *freq_table[MAX_CLUSTERS + 1]; 50 static atomic_t cluster_usage[MAX_CLUSTERS + 1]; 51 52 static unsigned int clk_big_min; /* (Big) clock frequencies */ 53 static unsigned int clk_little_max; /* Maximum clock frequency (Little) */ 54 55 static DEFINE_PER_CPU(unsigned int, physical_cluster); 56 static DEFINE_PER_CPU(unsigned int, cpu_last_req_freq); 57 58 static struct mutex cluster_lock[MAX_CLUSTERS]; 59 60 static inline int raw_cpu_to_cluster(int cpu) 61 { 62 return topology_physical_package_id(cpu); 63 } 64 65 static inline int cpu_to_cluster(int cpu) 66 { 67 return is_bL_switching_enabled() ? 68 MAX_CLUSTERS : raw_cpu_to_cluster(cpu); 69 } 70 71 static 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 87 static 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 99 static 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 else 104 return clk_get_cpu_rate(cpu); 105 } 106 107 static unsigned int 108 ve_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 it 131 * may be that clk_change_rate failed due to hardware or 132 * firmware issues and wasn't able to report that due to the 133 * current design of the clk core layer. To work around this 134 * problem we will read back the clock rate and check it is 135 * 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 */ 177 static 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 } 199 200 static 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 */ 211 static 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 */ 223 static 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 } 233 234 static 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 } 246 247 static 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 } 278 279 static 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 } 290 291 static 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 } 315 316 static 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 table 327 * so just check if the OPP count is non-zero 328 */ 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]); 345 346 out: 347 dev_err(cpu_dev, "%s: Failed to get data for cluster: %d\n", __func__, 348 cluster); 349 return ret; 350 } 351 352 static 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 of 370 * both 371 */ 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; 393 394 put_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 */ 410 static 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 } 449 450 static 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 } 463 464 static 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_SWITCHER 478 static 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 } 505 506 static struct notifier_block bL_switcher_notifier = { 507 .notifier_call = bL_cpufreq_switcher_notifier, 508 }; 509 510 static int __bLs_register_notifier(void) 511 { 512 return bL_switcher_register_notifier(&bL_switcher_notifier); 513 } 514 515 static int __bLs_unregister_notifier(void) 516 { 517 return bL_switcher_unregister_notifier(&bL_switcher_notifier); 518 } 519 #else 520 static int __bLs_register_notifier(void) { return 0; } 521 static int __bLs_unregister_notifier(void) { return 0; } 522 #endif 523 524 static 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 else 545 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 } 552 553 static 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 } 562 563 static struct platform_driver ve_spc_cpufreq_platdrv = { 564 .driver = { 565 .name = "vexpress-spc-cpufreq", 566 }, 567 .probe = ve_spc_cpufreq_probe, 568 .remove = ve_spc_cpufreq_remove, 569 }; 570 module_platform_driver(ve_spc_cpufreq_platdrv); 571 572 MODULE_ALIAS("platform:vexpress-spc-cpufreq"); 573 MODULE_AUTHOR("Viresh Kumar <viresh.kumar@linaro.org>"); 574 MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>"); 575 MODULE_DESCRIPTION("Vexpress SPC ARM big LITTLE cpufreq driver"); 576 MODULE_LICENSE("GPL v2"); 577