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/of_platform.h> 22 #include <linux/platform_device.h> 23 #include <linux/pm_opp.h> 24 #include <linux/slab.h> 25 #include <linux/topology.h> 26 #include <linux/types.h> 27 28 /* Currently we support only two clusters */ 29 #define A15_CLUSTER 0 30 #define A7_CLUSTER 1 31 #define MAX_CLUSTERS 2 32 33 #ifdef CONFIG_BL_SWITCHER 34 #include <asm/bL_switcher.h> 35 static bool bL_switching_enabled; 36 #define is_bL_switching_enabled() bL_switching_enabled 37 #define set_switching_enabled(x) (bL_switching_enabled = (x)) 38 #else 39 #define is_bL_switching_enabled() false 40 #define set_switching_enabled(x) do { } while (0) 41 #define bL_switch_request(...) do { } while (0) 42 #define bL_switcher_put_enabled() do { } while (0) 43 #define bL_switcher_get_enabled() do { } while (0) 44 #endif 45 46 #define ACTUAL_FREQ(cluster, freq) ((cluster == A7_CLUSTER) ? freq << 1 : freq) 47 #define VIRT_FREQ(cluster, freq) ((cluster == A7_CLUSTER) ? freq >> 1 : freq) 48 49 static struct clk *clk[MAX_CLUSTERS]; 50 static struct cpufreq_frequency_table *freq_table[MAX_CLUSTERS + 1]; 51 static atomic_t cluster_usage[MAX_CLUSTERS + 1]; 52 53 static unsigned int clk_big_min; /* (Big) clock frequencies */ 54 static unsigned int clk_little_max; /* Maximum clock frequency (Little) */ 55 56 static DEFINE_PER_CPU(unsigned int, physical_cluster); 57 static DEFINE_PER_CPU(unsigned int, cpu_last_req_freq); 58 59 static struct mutex cluster_lock[MAX_CLUSTERS]; 60 61 static inline int raw_cpu_to_cluster(int cpu) 62 { 63 return topology_physical_package_id(cpu); 64 } 65 66 static inline int cpu_to_cluster(int cpu) 67 { 68 return is_bL_switching_enabled() ? 69 MAX_CLUSTERS : raw_cpu_to_cluster(cpu); 70 } 71 72 static unsigned int find_cluster_maxfreq(int cluster) 73 { 74 int j; 75 u32 max_freq = 0, cpu_freq; 76 77 for_each_online_cpu(j) { 78 cpu_freq = per_cpu(cpu_last_req_freq, j); 79 80 if (cluster == per_cpu(physical_cluster, j) && 81 max_freq < cpu_freq) 82 max_freq = cpu_freq; 83 } 84 85 return max_freq; 86 } 87 88 static unsigned int clk_get_cpu_rate(unsigned int cpu) 89 { 90 u32 cur_cluster = per_cpu(physical_cluster, cpu); 91 u32 rate = clk_get_rate(clk[cur_cluster]) / 1000; 92 93 /* For switcher we use virtual A7 clock rates */ 94 if (is_bL_switching_enabled()) 95 rate = VIRT_FREQ(cur_cluster, rate); 96 97 return rate; 98 } 99 100 static unsigned int ve_spc_cpufreq_get_rate(unsigned int cpu) 101 { 102 if (is_bL_switching_enabled()) 103 return per_cpu(cpu_last_req_freq, cpu); 104 else 105 return clk_get_cpu_rate(cpu); 106 } 107 108 static unsigned int 109 ve_spc_cpufreq_set_rate(u32 cpu, u32 old_cluster, u32 new_cluster, u32 rate) 110 { 111 u32 new_rate, prev_rate; 112 int ret; 113 bool bLs = is_bL_switching_enabled(); 114 115 mutex_lock(&cluster_lock[new_cluster]); 116 117 if (bLs) { 118 prev_rate = per_cpu(cpu_last_req_freq, cpu); 119 per_cpu(cpu_last_req_freq, cpu) = rate; 120 per_cpu(physical_cluster, cpu) = new_cluster; 121 122 new_rate = find_cluster_maxfreq(new_cluster); 123 new_rate = ACTUAL_FREQ(new_cluster, new_rate); 124 } else { 125 new_rate = rate; 126 } 127 128 ret = clk_set_rate(clk[new_cluster], new_rate * 1000); 129 if (!ret) { 130 /* 131 * FIXME: clk_set_rate hasn't returned an error here however it 132 * may be that clk_change_rate failed due to hardware or 133 * firmware issues and wasn't able to report that due to the 134 * current design of the clk core layer. To work around this 135 * problem we will read back the clock rate and check it is 136 * correct. This needs to be removed once clk core is fixed. 137 */ 138 if (clk_get_rate(clk[new_cluster]) != new_rate * 1000) 139 ret = -EIO; 140 } 141 142 if (WARN_ON(ret)) { 143 if (bLs) { 144 per_cpu(cpu_last_req_freq, cpu) = prev_rate; 145 per_cpu(physical_cluster, cpu) = old_cluster; 146 } 147 148 mutex_unlock(&cluster_lock[new_cluster]); 149 150 return ret; 151 } 152 153 mutex_unlock(&cluster_lock[new_cluster]); 154 155 /* Recalc freq for old cluster when switching clusters */ 156 if (old_cluster != new_cluster) { 157 /* Switch cluster */ 158 bL_switch_request(cpu, new_cluster); 159 160 mutex_lock(&cluster_lock[old_cluster]); 161 162 /* Set freq of old cluster if there are cpus left on it */ 163 new_rate = find_cluster_maxfreq(old_cluster); 164 new_rate = ACTUAL_FREQ(old_cluster, new_rate); 165 166 if (new_rate && 167 clk_set_rate(clk[old_cluster], new_rate * 1000)) { 168 pr_err("%s: clk_set_rate failed: %d, old cluster: %d\n", 169 __func__, ret, old_cluster); 170 } 171 mutex_unlock(&cluster_lock[old_cluster]); 172 } 173 174 return 0; 175 } 176 177 /* Set clock frequency */ 178 static int ve_spc_cpufreq_set_target(struct cpufreq_policy *policy, 179 unsigned int index) 180 { 181 u32 cpu = policy->cpu, cur_cluster, new_cluster, actual_cluster; 182 unsigned int freqs_new; 183 184 cur_cluster = cpu_to_cluster(cpu); 185 new_cluster = actual_cluster = per_cpu(physical_cluster, cpu); 186 187 freqs_new = freq_table[cur_cluster][index].frequency; 188 189 if (is_bL_switching_enabled()) { 190 if (actual_cluster == A15_CLUSTER && freqs_new < clk_big_min) 191 new_cluster = A7_CLUSTER; 192 else if (actual_cluster == A7_CLUSTER && 193 freqs_new > clk_little_max) 194 new_cluster = A15_CLUSTER; 195 } 196 197 return ve_spc_cpufreq_set_rate(cpu, actual_cluster, new_cluster, 198 freqs_new); 199 } 200 201 static inline u32 get_table_count(struct cpufreq_frequency_table *table) 202 { 203 int count; 204 205 for (count = 0; table[count].frequency != CPUFREQ_TABLE_END; count++) 206 ; 207 208 return count; 209 } 210 211 /* get the minimum frequency in the cpufreq_frequency_table */ 212 static inline u32 get_table_min(struct cpufreq_frequency_table *table) 213 { 214 struct cpufreq_frequency_table *pos; 215 u32 min_freq = ~0; 216 217 cpufreq_for_each_entry(pos, table) 218 if (pos->frequency < min_freq) 219 min_freq = pos->frequency; 220 return min_freq; 221 } 222 223 /* get the maximum frequency in the cpufreq_frequency_table */ 224 static inline u32 get_table_max(struct cpufreq_frequency_table *table) 225 { 226 struct cpufreq_frequency_table *pos; 227 u32 max_freq = 0; 228 229 cpufreq_for_each_entry(pos, table) 230 if (pos->frequency > max_freq) 231 max_freq = pos->frequency; 232 return max_freq; 233 } 234 235 static bool search_frequency(struct cpufreq_frequency_table *table, int size, 236 unsigned int freq) 237 { 238 int count; 239 240 for (count = 0; count < size; count++) { 241 if (table[count].frequency == freq) 242 return true; 243 } 244 245 return false; 246 } 247 248 static int merge_cluster_tables(void) 249 { 250 int i, j, k = 0, count = 1; 251 struct cpufreq_frequency_table *table; 252 253 for (i = 0; i < MAX_CLUSTERS; i++) 254 count += get_table_count(freq_table[i]); 255 256 table = kcalloc(count, sizeof(*table), GFP_KERNEL); 257 if (!table) 258 return -ENOMEM; 259 260 freq_table[MAX_CLUSTERS] = table; 261 262 /* Add in reverse order to get freqs in increasing order */ 263 for (i = MAX_CLUSTERS - 1; i >= 0; i--, count = k) { 264 for (j = 0; freq_table[i][j].frequency != CPUFREQ_TABLE_END; 265 j++) { 266 if (i == A15_CLUSTER && 267 search_frequency(table, count, freq_table[i][j].frequency)) 268 continue; /* skip duplicates */ 269 table[k++].frequency = 270 VIRT_FREQ(i, freq_table[i][j].frequency); 271 } 272 } 273 274 table[k].driver_data = k; 275 table[k].frequency = CPUFREQ_TABLE_END; 276 277 return 0; 278 } 279 280 static void _put_cluster_clk_and_freq_table(struct device *cpu_dev, 281 const struct cpumask *cpumask) 282 { 283 u32 cluster = raw_cpu_to_cluster(cpu_dev->id); 284 285 if (!freq_table[cluster]) 286 return; 287 288 clk_put(clk[cluster]); 289 dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table[cluster]); 290 } 291 292 static void put_cluster_clk_and_freq_table(struct device *cpu_dev, 293 const struct cpumask *cpumask) 294 { 295 u32 cluster = cpu_to_cluster(cpu_dev->id); 296 int i; 297 298 if (atomic_dec_return(&cluster_usage[cluster])) 299 return; 300 301 if (cluster < MAX_CLUSTERS) 302 return _put_cluster_clk_and_freq_table(cpu_dev, cpumask); 303 304 for_each_present_cpu(i) { 305 struct device *cdev = get_cpu_device(i); 306 307 if (!cdev) 308 return; 309 310 _put_cluster_clk_and_freq_table(cdev, cpumask); 311 } 312 313 /* free virtual table */ 314 kfree(freq_table[cluster]); 315 } 316 317 static int _get_cluster_clk_and_freq_table(struct device *cpu_dev, 318 const struct cpumask *cpumask) 319 { 320 u32 cluster = raw_cpu_to_cluster(cpu_dev->id); 321 int ret; 322 323 if (freq_table[cluster]) 324 return 0; 325 326 /* 327 * platform specific SPC code must initialise the opp table 328 * so just check if the OPP count is non-zero 329 */ 330 ret = dev_pm_opp_get_opp_count(cpu_dev) <= 0; 331 if (ret) 332 goto out; 333 334 ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table[cluster]); 335 if (ret) 336 goto out; 337 338 clk[cluster] = clk_get(cpu_dev, NULL); 339 if (!IS_ERR(clk[cluster])) 340 return 0; 341 342 dev_err(cpu_dev, "%s: Failed to get clk for cpu: %d, cluster: %d\n", 343 __func__, cpu_dev->id, cluster); 344 ret = PTR_ERR(clk[cluster]); 345 dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table[cluster]); 346 347 out: 348 dev_err(cpu_dev, "%s: Failed to get data for cluster: %d\n", __func__, 349 cluster); 350 return ret; 351 } 352 353 static int get_cluster_clk_and_freq_table(struct device *cpu_dev, 354 const struct cpumask *cpumask) 355 { 356 u32 cluster = cpu_to_cluster(cpu_dev->id); 357 int i, ret; 358 359 if (atomic_inc_return(&cluster_usage[cluster]) != 1) 360 return 0; 361 362 if (cluster < MAX_CLUSTERS) { 363 ret = _get_cluster_clk_and_freq_table(cpu_dev, cpumask); 364 if (ret) 365 atomic_dec(&cluster_usage[cluster]); 366 return ret; 367 } 368 369 /* 370 * Get data for all clusters and fill virtual cluster with a merge of 371 * both 372 */ 373 for_each_present_cpu(i) { 374 struct device *cdev = get_cpu_device(i); 375 376 if (!cdev) 377 return -ENODEV; 378 379 ret = _get_cluster_clk_and_freq_table(cdev, cpumask); 380 if (ret) 381 goto put_clusters; 382 } 383 384 ret = merge_cluster_tables(); 385 if (ret) 386 goto put_clusters; 387 388 /* Assuming 2 cluster, set clk_big_min and clk_little_max */ 389 clk_big_min = get_table_min(freq_table[A15_CLUSTER]); 390 clk_little_max = VIRT_FREQ(A7_CLUSTER, 391 get_table_max(freq_table[A7_CLUSTER])); 392 393 return 0; 394 395 put_clusters: 396 for_each_present_cpu(i) { 397 struct device *cdev = get_cpu_device(i); 398 399 if (!cdev) 400 return -ENODEV; 401 402 _put_cluster_clk_and_freq_table(cdev, cpumask); 403 } 404 405 atomic_dec(&cluster_usage[cluster]); 406 407 return ret; 408 } 409 410 /* Per-CPU initialization */ 411 static int ve_spc_cpufreq_init(struct cpufreq_policy *policy) 412 { 413 u32 cur_cluster = cpu_to_cluster(policy->cpu); 414 struct device *cpu_dev; 415 int ret; 416 417 cpu_dev = get_cpu_device(policy->cpu); 418 if (!cpu_dev) { 419 pr_err("%s: failed to get cpu%d device\n", __func__, 420 policy->cpu); 421 return -ENODEV; 422 } 423 424 if (cur_cluster < MAX_CLUSTERS) { 425 int cpu; 426 427 dev_pm_opp_get_sharing_cpus(cpu_dev, policy->cpus); 428 429 for_each_cpu(cpu, policy->cpus) 430 per_cpu(physical_cluster, cpu) = cur_cluster; 431 } else { 432 /* Assumption: during init, we are always running on A15 */ 433 per_cpu(physical_cluster, policy->cpu) = A15_CLUSTER; 434 } 435 436 ret = get_cluster_clk_and_freq_table(cpu_dev, policy->cpus); 437 if (ret) 438 return ret; 439 440 policy->freq_table = freq_table[cur_cluster]; 441 policy->cpuinfo.transition_latency = 1000000; /* 1 ms */ 442 443 if (is_bL_switching_enabled()) 444 per_cpu(cpu_last_req_freq, policy->cpu) = 445 clk_get_cpu_rate(policy->cpu); 446 447 dev_info(cpu_dev, "%s: CPU %d initialized\n", __func__, policy->cpu); 448 return 0; 449 } 450 451 static int ve_spc_cpufreq_exit(struct cpufreq_policy *policy) 452 { 453 struct device *cpu_dev; 454 455 cpu_dev = get_cpu_device(policy->cpu); 456 if (!cpu_dev) { 457 pr_err("%s: failed to get cpu%d device\n", __func__, 458 policy->cpu); 459 return -ENODEV; 460 } 461 462 put_cluster_clk_and_freq_table(cpu_dev, policy->related_cpus); 463 return 0; 464 } 465 466 static struct cpufreq_driver ve_spc_cpufreq_driver = { 467 .name = "vexpress-spc", 468 .flags = CPUFREQ_HAVE_GOVERNOR_PER_POLICY | 469 CPUFREQ_NEED_INITIAL_FREQ_CHECK, 470 .verify = cpufreq_generic_frequency_table_verify, 471 .target_index = ve_spc_cpufreq_set_target, 472 .get = ve_spc_cpufreq_get_rate, 473 .init = ve_spc_cpufreq_init, 474 .exit = ve_spc_cpufreq_exit, 475 .register_em = cpufreq_register_em_with_opp, 476 .attr = cpufreq_generic_attr, 477 }; 478 479 #ifdef CONFIG_BL_SWITCHER 480 static int bL_cpufreq_switcher_notifier(struct notifier_block *nfb, 481 unsigned long action, void *_arg) 482 { 483 pr_debug("%s: action: %ld\n", __func__, action); 484 485 switch (action) { 486 case BL_NOTIFY_PRE_ENABLE: 487 case BL_NOTIFY_PRE_DISABLE: 488 cpufreq_unregister_driver(&ve_spc_cpufreq_driver); 489 break; 490 491 case BL_NOTIFY_POST_ENABLE: 492 set_switching_enabled(true); 493 cpufreq_register_driver(&ve_spc_cpufreq_driver); 494 break; 495 496 case BL_NOTIFY_POST_DISABLE: 497 set_switching_enabled(false); 498 cpufreq_register_driver(&ve_spc_cpufreq_driver); 499 break; 500 501 default: 502 return NOTIFY_DONE; 503 } 504 505 return NOTIFY_OK; 506 } 507 508 static struct notifier_block bL_switcher_notifier = { 509 .notifier_call = bL_cpufreq_switcher_notifier, 510 }; 511 512 static int __bLs_register_notifier(void) 513 { 514 return bL_switcher_register_notifier(&bL_switcher_notifier); 515 } 516 517 static int __bLs_unregister_notifier(void) 518 { 519 return bL_switcher_unregister_notifier(&bL_switcher_notifier); 520 } 521 #else 522 static int __bLs_register_notifier(void) { return 0; } 523 static int __bLs_unregister_notifier(void) { return 0; } 524 #endif 525 526 static int ve_spc_cpufreq_probe(struct platform_device *pdev) 527 { 528 int ret, i; 529 530 set_switching_enabled(bL_switcher_get_enabled()); 531 532 for (i = 0; i < MAX_CLUSTERS; i++) 533 mutex_init(&cluster_lock[i]); 534 535 if (!is_bL_switching_enabled()) 536 ve_spc_cpufreq_driver.flags |= CPUFREQ_IS_COOLING_DEV; 537 538 ret = cpufreq_register_driver(&ve_spc_cpufreq_driver); 539 if (ret) { 540 pr_info("%s: Failed registering platform driver: %s, err: %d\n", 541 __func__, ve_spc_cpufreq_driver.name, ret); 542 } else { 543 ret = __bLs_register_notifier(); 544 if (ret) 545 cpufreq_unregister_driver(&ve_spc_cpufreq_driver); 546 else 547 pr_info("%s: Registered platform driver: %s\n", 548 __func__, ve_spc_cpufreq_driver.name); 549 } 550 551 bL_switcher_put_enabled(); 552 return ret; 553 } 554 555 static int ve_spc_cpufreq_remove(struct platform_device *pdev) 556 { 557 bL_switcher_get_enabled(); 558 __bLs_unregister_notifier(); 559 cpufreq_unregister_driver(&ve_spc_cpufreq_driver); 560 bL_switcher_put_enabled(); 561 pr_info("%s: Un-registered platform driver: %s\n", __func__, 562 ve_spc_cpufreq_driver.name); 563 return 0; 564 } 565 566 static struct platform_driver ve_spc_cpufreq_platdrv = { 567 .driver = { 568 .name = "vexpress-spc-cpufreq", 569 }, 570 .probe = ve_spc_cpufreq_probe, 571 .remove = ve_spc_cpufreq_remove, 572 }; 573 module_platform_driver(ve_spc_cpufreq_platdrv); 574 575 MODULE_ALIAS("platform:vexpress-spc-cpufreq"); 576 MODULE_AUTHOR("Viresh Kumar <viresh.kumar@linaro.org>"); 577 MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>"); 578 MODULE_DESCRIPTION("Vexpress SPC ARM big LITTLE cpufreq driver"); 579 MODULE_LICENSE("GPL v2"); 580