| 1 | /* |
| 2 | * linux/drivers/cpufreq/cpufreq.c |
| 3 | * |
| 4 | * Copyright (C) 2001 Russell King |
| 5 | * (C) 2002 - 2003 Dominik Brodowski <linux@brodo.de> |
| 6 | * (C) 2013 Viresh Kumar <viresh.kumar@linaro.org> |
| 7 | * |
| 8 | * Oct 2005 - Ashok Raj <ashok.raj@intel.com> |
| 9 | * Added handling for CPU hotplug |
| 10 | * Feb 2006 - Jacob Shin <jacob.shin@amd.com> |
| 11 | * Fix handling for CPU hotplug -- affected CPUs |
| 12 | * |
| 13 | * This program is free software; you can redistribute it and/or modify |
| 14 | * it under the terms of the GNU General Public License version 2 as |
| 15 | * published by the Free Software Foundation. |
| 16 | */ |
| 17 | |
| 18 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
| 19 | |
| 20 | #include <linux/cpu.h> |
| 21 | #include <linux/cpufreq.h> |
| 22 | #include <linux/delay.h> |
| 23 | #include <linux/device.h> |
| 24 | #include <linux/init.h> |
| 25 | #include <linux/kernel_stat.h> |
| 26 | #include <linux/module.h> |
| 27 | #include <linux/mutex.h> |
| 28 | #include <linux/slab.h> |
| 29 | #include <linux/syscore_ops.h> |
| 30 | #include <linux/tick.h> |
| 31 | #include <trace/events/power.h> |
| 32 | |
| 33 | /** |
| 34 | * The "cpufreq driver" - the arch- or hardware-dependent low |
| 35 | * level driver of CPUFreq support, and its spinlock. This lock |
| 36 | * also protects the cpufreq_cpu_data array. |
| 37 | */ |
| 38 | static struct cpufreq_driver *cpufreq_driver; |
| 39 | static DEFINE_PER_CPU(struct cpufreq_policy *, cpufreq_cpu_data); |
| 40 | static DEFINE_PER_CPU(struct cpufreq_policy *, cpufreq_cpu_data_fallback); |
| 41 | static DEFINE_RWLOCK(cpufreq_driver_lock); |
| 42 | static DEFINE_MUTEX(cpufreq_governor_lock); |
| 43 | static LIST_HEAD(cpufreq_policy_list); |
| 44 | |
| 45 | #ifdef CONFIG_HOTPLUG_CPU |
| 46 | /* This one keeps track of the previously set governor of a removed CPU */ |
| 47 | static DEFINE_PER_CPU(char[CPUFREQ_NAME_LEN], cpufreq_cpu_governor); |
| 48 | #endif |
| 49 | |
| 50 | /* |
| 51 | * cpu_policy_rwsem is a per CPU reader-writer semaphore designed to cure |
| 52 | * all cpufreq/hotplug/workqueue/etc related lock issues. |
| 53 | * |
| 54 | * The rules for this semaphore: |
| 55 | * - Any routine that wants to read from the policy structure will |
| 56 | * do a down_read on this semaphore. |
| 57 | * - Any routine that will write to the policy structure and/or may take away |
| 58 | * the policy altogether (eg. CPU hotplug), will hold this lock in write |
| 59 | * mode before doing so. |
| 60 | * |
| 61 | * Additional rules: |
| 62 | * - Governor routines that can be called in cpufreq hotplug path should not |
| 63 | * take this sem as top level hotplug notifier handler takes this. |
| 64 | * - Lock should not be held across |
| 65 | * __cpufreq_governor(data, CPUFREQ_GOV_STOP); |
| 66 | */ |
| 67 | static DEFINE_PER_CPU(struct rw_semaphore, cpu_policy_rwsem); |
| 68 | |
| 69 | #define lock_policy_rwsem(mode, cpu) \ |
| 70 | static int lock_policy_rwsem_##mode(int cpu) \ |
| 71 | { \ |
| 72 | struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu); \ |
| 73 | BUG_ON(!policy); \ |
| 74 | down_##mode(&per_cpu(cpu_policy_rwsem, policy->cpu)); \ |
| 75 | \ |
| 76 | return 0; \ |
| 77 | } |
| 78 | |
| 79 | lock_policy_rwsem(read, cpu); |
| 80 | lock_policy_rwsem(write, cpu); |
| 81 | |
| 82 | #define unlock_policy_rwsem(mode, cpu) \ |
| 83 | static void unlock_policy_rwsem_##mode(int cpu) \ |
| 84 | { \ |
| 85 | struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu); \ |
| 86 | BUG_ON(!policy); \ |
| 87 | up_##mode(&per_cpu(cpu_policy_rwsem, policy->cpu)); \ |
| 88 | } |
| 89 | |
| 90 | unlock_policy_rwsem(read, cpu); |
| 91 | unlock_policy_rwsem(write, cpu); |
| 92 | |
| 93 | /* |
| 94 | * rwsem to guarantee that cpufreq driver module doesn't unload during critical |
| 95 | * sections |
| 96 | */ |
| 97 | static DECLARE_RWSEM(cpufreq_rwsem); |
| 98 | |
| 99 | /* internal prototypes */ |
| 100 | static int __cpufreq_governor(struct cpufreq_policy *policy, |
| 101 | unsigned int event); |
| 102 | static unsigned int __cpufreq_get(unsigned int cpu); |
| 103 | static void handle_update(struct work_struct *work); |
| 104 | |
| 105 | /** |
| 106 | * Two notifier lists: the "policy" list is involved in the |
| 107 | * validation process for a new CPU frequency policy; the |
| 108 | * "transition" list for kernel code that needs to handle |
| 109 | * changes to devices when the CPU clock speed changes. |
| 110 | * The mutex locks both lists. |
| 111 | */ |
| 112 | static BLOCKING_NOTIFIER_HEAD(cpufreq_policy_notifier_list); |
| 113 | static struct srcu_notifier_head cpufreq_transition_notifier_list; |
| 114 | |
| 115 | static bool init_cpufreq_transition_notifier_list_called; |
| 116 | static int __init init_cpufreq_transition_notifier_list(void) |
| 117 | { |
| 118 | srcu_init_notifier_head(&cpufreq_transition_notifier_list); |
| 119 | init_cpufreq_transition_notifier_list_called = true; |
| 120 | return 0; |
| 121 | } |
| 122 | pure_initcall(init_cpufreq_transition_notifier_list); |
| 123 | |
| 124 | static int off __read_mostly; |
| 125 | static int cpufreq_disabled(void) |
| 126 | { |
| 127 | return off; |
| 128 | } |
| 129 | void disable_cpufreq(void) |
| 130 | { |
| 131 | off = 1; |
| 132 | } |
| 133 | static LIST_HEAD(cpufreq_governor_list); |
| 134 | static DEFINE_MUTEX(cpufreq_governor_mutex); |
| 135 | |
| 136 | bool have_governor_per_policy(void) |
| 137 | { |
| 138 | return cpufreq_driver->have_governor_per_policy; |
| 139 | } |
| 140 | EXPORT_SYMBOL_GPL(have_governor_per_policy); |
| 141 | |
| 142 | struct kobject *get_governor_parent_kobj(struct cpufreq_policy *policy) |
| 143 | { |
| 144 | if (have_governor_per_policy()) |
| 145 | return &policy->kobj; |
| 146 | else |
| 147 | return cpufreq_global_kobject; |
| 148 | } |
| 149 | EXPORT_SYMBOL_GPL(get_governor_parent_kobj); |
| 150 | |
| 151 | static inline u64 get_cpu_idle_time_jiffy(unsigned int cpu, u64 *wall) |
| 152 | { |
| 153 | u64 idle_time; |
| 154 | u64 cur_wall_time; |
| 155 | u64 busy_time; |
| 156 | |
| 157 | cur_wall_time = jiffies64_to_cputime64(get_jiffies_64()); |
| 158 | |
| 159 | busy_time = kcpustat_cpu(cpu).cpustat[CPUTIME_USER]; |
| 160 | busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_SYSTEM]; |
| 161 | busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_IRQ]; |
| 162 | busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_SOFTIRQ]; |
| 163 | busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_STEAL]; |
| 164 | busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_NICE]; |
| 165 | |
| 166 | idle_time = cur_wall_time - busy_time; |
| 167 | if (wall) |
| 168 | *wall = cputime_to_usecs(cur_wall_time); |
| 169 | |
| 170 | return cputime_to_usecs(idle_time); |
| 171 | } |
| 172 | |
| 173 | u64 get_cpu_idle_time(unsigned int cpu, u64 *wall, int io_busy) |
| 174 | { |
| 175 | u64 idle_time = get_cpu_idle_time_us(cpu, io_busy ? wall : NULL); |
| 176 | |
| 177 | if (idle_time == -1ULL) |
| 178 | return get_cpu_idle_time_jiffy(cpu, wall); |
| 179 | else if (!io_busy) |
| 180 | idle_time += get_cpu_iowait_time_us(cpu, wall); |
| 181 | |
| 182 | return idle_time; |
| 183 | } |
| 184 | EXPORT_SYMBOL_GPL(get_cpu_idle_time); |
| 185 | |
| 186 | struct cpufreq_policy *cpufreq_cpu_get(unsigned int cpu) |
| 187 | { |
| 188 | struct cpufreq_policy *policy = NULL; |
| 189 | unsigned long flags; |
| 190 | |
| 191 | if (cpufreq_disabled() || (cpu >= nr_cpu_ids)) |
| 192 | return NULL; |
| 193 | |
| 194 | if (!down_read_trylock(&cpufreq_rwsem)) |
| 195 | return NULL; |
| 196 | |
| 197 | /* get the cpufreq driver */ |
| 198 | read_lock_irqsave(&cpufreq_driver_lock, flags); |
| 199 | |
| 200 | if (cpufreq_driver) { |
| 201 | /* get the CPU */ |
| 202 | policy = per_cpu(cpufreq_cpu_data, cpu); |
| 203 | if (policy) |
| 204 | kobject_get(&policy->kobj); |
| 205 | } |
| 206 | |
| 207 | read_unlock_irqrestore(&cpufreq_driver_lock, flags); |
| 208 | |
| 209 | if (!policy) |
| 210 | up_read(&cpufreq_rwsem); |
| 211 | |
| 212 | return policy; |
| 213 | } |
| 214 | EXPORT_SYMBOL_GPL(cpufreq_cpu_get); |
| 215 | |
| 216 | void cpufreq_cpu_put(struct cpufreq_policy *policy) |
| 217 | { |
| 218 | if (cpufreq_disabled()) |
| 219 | return; |
| 220 | |
| 221 | kobject_put(&policy->kobj); |
| 222 | up_read(&cpufreq_rwsem); |
| 223 | } |
| 224 | EXPORT_SYMBOL_GPL(cpufreq_cpu_put); |
| 225 | |
| 226 | /********************************************************************* |
| 227 | * EXTERNALLY AFFECTING FREQUENCY CHANGES * |
| 228 | *********************************************************************/ |
| 229 | |
| 230 | /** |
| 231 | * adjust_jiffies - adjust the system "loops_per_jiffy" |
| 232 | * |
| 233 | * This function alters the system "loops_per_jiffy" for the clock |
| 234 | * speed change. Note that loops_per_jiffy cannot be updated on SMP |
| 235 | * systems as each CPU might be scaled differently. So, use the arch |
| 236 | * per-CPU loops_per_jiffy value wherever possible. |
| 237 | */ |
| 238 | #ifndef CONFIG_SMP |
| 239 | static unsigned long l_p_j_ref; |
| 240 | static unsigned int l_p_j_ref_freq; |
| 241 | |
| 242 | static void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci) |
| 243 | { |
| 244 | if (ci->flags & CPUFREQ_CONST_LOOPS) |
| 245 | return; |
| 246 | |
| 247 | if (!l_p_j_ref_freq) { |
| 248 | l_p_j_ref = loops_per_jiffy; |
| 249 | l_p_j_ref_freq = ci->old; |
| 250 | pr_debug("saving %lu as reference value for loops_per_jiffy; " |
| 251 | "freq is %u kHz\n", l_p_j_ref, l_p_j_ref_freq); |
| 252 | } |
| 253 | if ((val == CPUFREQ_POSTCHANGE && ci->old != ci->new) || |
| 254 | (val == CPUFREQ_RESUMECHANGE || val == CPUFREQ_SUSPENDCHANGE)) { |
| 255 | loops_per_jiffy = cpufreq_scale(l_p_j_ref, l_p_j_ref_freq, |
| 256 | ci->new); |
| 257 | pr_debug("scaling loops_per_jiffy to %lu " |
| 258 | "for frequency %u kHz\n", loops_per_jiffy, ci->new); |
| 259 | } |
| 260 | } |
| 261 | #else |
| 262 | static inline void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci) |
| 263 | { |
| 264 | return; |
| 265 | } |
| 266 | #endif |
| 267 | |
| 268 | static void __cpufreq_notify_transition(struct cpufreq_policy *policy, |
| 269 | struct cpufreq_freqs *freqs, unsigned int state) |
| 270 | { |
| 271 | BUG_ON(irqs_disabled()); |
| 272 | |
| 273 | if (cpufreq_disabled()) |
| 274 | return; |
| 275 | |
| 276 | freqs->flags = cpufreq_driver->flags; |
| 277 | pr_debug("notification %u of frequency transition to %u kHz\n", |
| 278 | state, freqs->new); |
| 279 | |
| 280 | switch (state) { |
| 281 | |
| 282 | case CPUFREQ_PRECHANGE: |
| 283 | /* detect if the driver reported a value as "old frequency" |
| 284 | * which is not equal to what the cpufreq core thinks is |
| 285 | * "old frequency". |
| 286 | */ |
| 287 | if (!(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) { |
| 288 | if ((policy) && (policy->cpu == freqs->cpu) && |
| 289 | (policy->cur) && (policy->cur != freqs->old)) { |
| 290 | pr_debug("Warning: CPU frequency is" |
| 291 | " %u, cpufreq assumed %u kHz.\n", |
| 292 | freqs->old, policy->cur); |
| 293 | freqs->old = policy->cur; |
| 294 | } |
| 295 | } |
| 296 | srcu_notifier_call_chain(&cpufreq_transition_notifier_list, |
| 297 | CPUFREQ_PRECHANGE, freqs); |
| 298 | adjust_jiffies(CPUFREQ_PRECHANGE, freqs); |
| 299 | break; |
| 300 | |
| 301 | case CPUFREQ_POSTCHANGE: |
| 302 | adjust_jiffies(CPUFREQ_POSTCHANGE, freqs); |
| 303 | pr_debug("FREQ: %lu - CPU: %lu", (unsigned long)freqs->new, |
| 304 | (unsigned long)freqs->cpu); |
| 305 | trace_cpu_frequency(freqs->new, freqs->cpu); |
| 306 | srcu_notifier_call_chain(&cpufreq_transition_notifier_list, |
| 307 | CPUFREQ_POSTCHANGE, freqs); |
| 308 | if (likely(policy) && likely(policy->cpu == freqs->cpu)) |
| 309 | policy->cur = freqs->new; |
| 310 | break; |
| 311 | } |
| 312 | } |
| 313 | |
| 314 | /** |
| 315 | * cpufreq_notify_transition - call notifier chain and adjust_jiffies |
| 316 | * on frequency transition. |
| 317 | * |
| 318 | * This function calls the transition notifiers and the "adjust_jiffies" |
| 319 | * function. It is called twice on all CPU frequency changes that have |
| 320 | * external effects. |
| 321 | */ |
| 322 | void cpufreq_notify_transition(struct cpufreq_policy *policy, |
| 323 | struct cpufreq_freqs *freqs, unsigned int state) |
| 324 | { |
| 325 | for_each_cpu(freqs->cpu, policy->cpus) |
| 326 | __cpufreq_notify_transition(policy, freqs, state); |
| 327 | } |
| 328 | EXPORT_SYMBOL_GPL(cpufreq_notify_transition); |
| 329 | |
| 330 | |
| 331 | /********************************************************************* |
| 332 | * SYSFS INTERFACE * |
| 333 | *********************************************************************/ |
| 334 | |
| 335 | static struct cpufreq_governor *__find_governor(const char *str_governor) |
| 336 | { |
| 337 | struct cpufreq_governor *t; |
| 338 | |
| 339 | list_for_each_entry(t, &cpufreq_governor_list, governor_list) |
| 340 | if (!strnicmp(str_governor, t->name, CPUFREQ_NAME_LEN)) |
| 341 | return t; |
| 342 | |
| 343 | return NULL; |
| 344 | } |
| 345 | |
| 346 | /** |
| 347 | * cpufreq_parse_governor - parse a governor string |
| 348 | */ |
| 349 | static int cpufreq_parse_governor(char *str_governor, unsigned int *policy, |
| 350 | struct cpufreq_governor **governor) |
| 351 | { |
| 352 | int err = -EINVAL; |
| 353 | |
| 354 | if (!cpufreq_driver) |
| 355 | goto out; |
| 356 | |
| 357 | if (cpufreq_driver->setpolicy) { |
| 358 | if (!strnicmp(str_governor, "performance", CPUFREQ_NAME_LEN)) { |
| 359 | *policy = CPUFREQ_POLICY_PERFORMANCE; |
| 360 | err = 0; |
| 361 | } else if (!strnicmp(str_governor, "powersave", |
| 362 | CPUFREQ_NAME_LEN)) { |
| 363 | *policy = CPUFREQ_POLICY_POWERSAVE; |
| 364 | err = 0; |
| 365 | } |
| 366 | } else if (cpufreq_driver->target) { |
| 367 | struct cpufreq_governor *t; |
| 368 | |
| 369 | mutex_lock(&cpufreq_governor_mutex); |
| 370 | |
| 371 | t = __find_governor(str_governor); |
| 372 | |
| 373 | if (t == NULL) { |
| 374 | int ret; |
| 375 | |
| 376 | mutex_unlock(&cpufreq_governor_mutex); |
| 377 | ret = request_module("cpufreq_%s", str_governor); |
| 378 | mutex_lock(&cpufreq_governor_mutex); |
| 379 | |
| 380 | if (ret == 0) |
| 381 | t = __find_governor(str_governor); |
| 382 | } |
| 383 | |
| 384 | if (t != NULL) { |
| 385 | *governor = t; |
| 386 | err = 0; |
| 387 | } |
| 388 | |
| 389 | mutex_unlock(&cpufreq_governor_mutex); |
| 390 | } |
| 391 | out: |
| 392 | return err; |
| 393 | } |
| 394 | |
| 395 | /** |
| 396 | * cpufreq_per_cpu_attr_read() / show_##file_name() - |
| 397 | * print out cpufreq information |
| 398 | * |
| 399 | * Write out information from cpufreq_driver->policy[cpu]; object must be |
| 400 | * "unsigned int". |
| 401 | */ |
| 402 | |
| 403 | #define show_one(file_name, object) \ |
| 404 | static ssize_t show_##file_name \ |
| 405 | (struct cpufreq_policy *policy, char *buf) \ |
| 406 | { \ |
| 407 | return sprintf(buf, "%u\n", policy->object); \ |
| 408 | } |
| 409 | |
| 410 | show_one(cpuinfo_min_freq, cpuinfo.min_freq); |
| 411 | show_one(cpuinfo_max_freq, cpuinfo.max_freq); |
| 412 | show_one(cpuinfo_transition_latency, cpuinfo.transition_latency); |
| 413 | show_one(scaling_min_freq, min); |
| 414 | show_one(scaling_max_freq, max); |
| 415 | show_one(scaling_cur_freq, cur); |
| 416 | |
| 417 | static int __cpufreq_set_policy(struct cpufreq_policy *policy, |
| 418 | struct cpufreq_policy *new_policy); |
| 419 | |
| 420 | /** |
| 421 | * cpufreq_per_cpu_attr_write() / store_##file_name() - sysfs write access |
| 422 | */ |
| 423 | #define store_one(file_name, object) \ |
| 424 | static ssize_t store_##file_name \ |
| 425 | (struct cpufreq_policy *policy, const char *buf, size_t count) \ |
| 426 | { \ |
| 427 | int ret; \ |
| 428 | struct cpufreq_policy new_policy; \ |
| 429 | \ |
| 430 | ret = cpufreq_get_policy(&new_policy, policy->cpu); \ |
| 431 | if (ret) \ |
| 432 | return -EINVAL; \ |
| 433 | \ |
| 434 | ret = sscanf(buf, "%u", &new_policy.object); \ |
| 435 | if (ret != 1) \ |
| 436 | return -EINVAL; \ |
| 437 | \ |
| 438 | ret = __cpufreq_set_policy(policy, &new_policy); \ |
| 439 | policy->user_policy.object = policy->object; \ |
| 440 | \ |
| 441 | return ret ? ret : count; \ |
| 442 | } |
| 443 | |
| 444 | store_one(scaling_min_freq, min); |
| 445 | store_one(scaling_max_freq, max); |
| 446 | |
| 447 | /** |
| 448 | * show_cpuinfo_cur_freq - current CPU frequency as detected by hardware |
| 449 | */ |
| 450 | static ssize_t show_cpuinfo_cur_freq(struct cpufreq_policy *policy, |
| 451 | char *buf) |
| 452 | { |
| 453 | unsigned int cur_freq = __cpufreq_get(policy->cpu); |
| 454 | if (!cur_freq) |
| 455 | return sprintf(buf, "<unknown>"); |
| 456 | return sprintf(buf, "%u\n", cur_freq); |
| 457 | } |
| 458 | |
| 459 | /** |
| 460 | * show_scaling_governor - show the current policy for the specified CPU |
| 461 | */ |
| 462 | static ssize_t show_scaling_governor(struct cpufreq_policy *policy, char *buf) |
| 463 | { |
| 464 | if (policy->policy == CPUFREQ_POLICY_POWERSAVE) |
| 465 | return sprintf(buf, "powersave\n"); |
| 466 | else if (policy->policy == CPUFREQ_POLICY_PERFORMANCE) |
| 467 | return sprintf(buf, "performance\n"); |
| 468 | else if (policy->governor) |
| 469 | return scnprintf(buf, CPUFREQ_NAME_PLEN, "%s\n", |
| 470 | policy->governor->name); |
| 471 | return -EINVAL; |
| 472 | } |
| 473 | |
| 474 | /** |
| 475 | * store_scaling_governor - store policy for the specified CPU |
| 476 | */ |
| 477 | static ssize_t store_scaling_governor(struct cpufreq_policy *policy, |
| 478 | const char *buf, size_t count) |
| 479 | { |
| 480 | int ret; |
| 481 | char str_governor[16]; |
| 482 | struct cpufreq_policy new_policy; |
| 483 | |
| 484 | ret = cpufreq_get_policy(&new_policy, policy->cpu); |
| 485 | if (ret) |
| 486 | return ret; |
| 487 | |
| 488 | ret = sscanf(buf, "%15s", str_governor); |
| 489 | if (ret != 1) |
| 490 | return -EINVAL; |
| 491 | |
| 492 | if (cpufreq_parse_governor(str_governor, &new_policy.policy, |
| 493 | &new_policy.governor)) |
| 494 | return -EINVAL; |
| 495 | |
| 496 | /* |
| 497 | * Do not use cpufreq_set_policy here or the user_policy.max |
| 498 | * will be wrongly overridden |
| 499 | */ |
| 500 | ret = __cpufreq_set_policy(policy, &new_policy); |
| 501 | |
| 502 | policy->user_policy.policy = policy->policy; |
| 503 | policy->user_policy.governor = policy->governor; |
| 504 | |
| 505 | if (ret) |
| 506 | return ret; |
| 507 | else |
| 508 | return count; |
| 509 | } |
| 510 | |
| 511 | /** |
| 512 | * show_scaling_driver - show the cpufreq driver currently loaded |
| 513 | */ |
| 514 | static ssize_t show_scaling_driver(struct cpufreq_policy *policy, char *buf) |
| 515 | { |
| 516 | return scnprintf(buf, CPUFREQ_NAME_PLEN, "%s\n", cpufreq_driver->name); |
| 517 | } |
| 518 | |
| 519 | /** |
| 520 | * show_scaling_available_governors - show the available CPUfreq governors |
| 521 | */ |
| 522 | static ssize_t show_scaling_available_governors(struct cpufreq_policy *policy, |
| 523 | char *buf) |
| 524 | { |
| 525 | ssize_t i = 0; |
| 526 | struct cpufreq_governor *t; |
| 527 | |
| 528 | if (!cpufreq_driver->target) { |
| 529 | i += sprintf(buf, "performance powersave"); |
| 530 | goto out; |
| 531 | } |
| 532 | |
| 533 | list_for_each_entry(t, &cpufreq_governor_list, governor_list) { |
| 534 | if (i >= (ssize_t) ((PAGE_SIZE / sizeof(char)) |
| 535 | - (CPUFREQ_NAME_LEN + 2))) |
| 536 | goto out; |
| 537 | i += scnprintf(&buf[i], CPUFREQ_NAME_PLEN, "%s ", t->name); |
| 538 | } |
| 539 | out: |
| 540 | i += sprintf(&buf[i], "\n"); |
| 541 | return i; |
| 542 | } |
| 543 | |
| 544 | ssize_t cpufreq_show_cpus(const struct cpumask *mask, char *buf) |
| 545 | { |
| 546 | ssize_t i = 0; |
| 547 | unsigned int cpu; |
| 548 | |
| 549 | for_each_cpu(cpu, mask) { |
| 550 | if (i) |
| 551 | i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), " "); |
| 552 | i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), "%u", cpu); |
| 553 | if (i >= (PAGE_SIZE - 5)) |
| 554 | break; |
| 555 | } |
| 556 | i += sprintf(&buf[i], "\n"); |
| 557 | return i; |
| 558 | } |
| 559 | EXPORT_SYMBOL_GPL(cpufreq_show_cpus); |
| 560 | |
| 561 | /** |
| 562 | * show_related_cpus - show the CPUs affected by each transition even if |
| 563 | * hw coordination is in use |
| 564 | */ |
| 565 | static ssize_t show_related_cpus(struct cpufreq_policy *policy, char *buf) |
| 566 | { |
| 567 | return cpufreq_show_cpus(policy->related_cpus, buf); |
| 568 | } |
| 569 | |
| 570 | /** |
| 571 | * show_affected_cpus - show the CPUs affected by each transition |
| 572 | */ |
| 573 | static ssize_t show_affected_cpus(struct cpufreq_policy *policy, char *buf) |
| 574 | { |
| 575 | return cpufreq_show_cpus(policy->cpus, buf); |
| 576 | } |
| 577 | |
| 578 | static ssize_t store_scaling_setspeed(struct cpufreq_policy *policy, |
| 579 | const char *buf, size_t count) |
| 580 | { |
| 581 | unsigned int freq = 0; |
| 582 | unsigned int ret; |
| 583 | |
| 584 | if (!policy->governor || !policy->governor->store_setspeed) |
| 585 | return -EINVAL; |
| 586 | |
| 587 | ret = sscanf(buf, "%u", &freq); |
| 588 | if (ret != 1) |
| 589 | return -EINVAL; |
| 590 | |
| 591 | policy->governor->store_setspeed(policy, freq); |
| 592 | |
| 593 | return count; |
| 594 | } |
| 595 | |
| 596 | static ssize_t show_scaling_setspeed(struct cpufreq_policy *policy, char *buf) |
| 597 | { |
| 598 | if (!policy->governor || !policy->governor->show_setspeed) |
| 599 | return sprintf(buf, "<unsupported>\n"); |
| 600 | |
| 601 | return policy->governor->show_setspeed(policy, buf); |
| 602 | } |
| 603 | |
| 604 | /** |
| 605 | * show_bios_limit - show the current cpufreq HW/BIOS limitation |
| 606 | */ |
| 607 | static ssize_t show_bios_limit(struct cpufreq_policy *policy, char *buf) |
| 608 | { |
| 609 | unsigned int limit; |
| 610 | int ret; |
| 611 | if (cpufreq_driver->bios_limit) { |
| 612 | ret = cpufreq_driver->bios_limit(policy->cpu, &limit); |
| 613 | if (!ret) |
| 614 | return sprintf(buf, "%u\n", limit); |
| 615 | } |
| 616 | return sprintf(buf, "%u\n", policy->cpuinfo.max_freq); |
| 617 | } |
| 618 | |
| 619 | cpufreq_freq_attr_ro_perm(cpuinfo_cur_freq, 0400); |
| 620 | cpufreq_freq_attr_ro(cpuinfo_min_freq); |
| 621 | cpufreq_freq_attr_ro(cpuinfo_max_freq); |
| 622 | cpufreq_freq_attr_ro(cpuinfo_transition_latency); |
| 623 | cpufreq_freq_attr_ro(scaling_available_governors); |
| 624 | cpufreq_freq_attr_ro(scaling_driver); |
| 625 | cpufreq_freq_attr_ro(scaling_cur_freq); |
| 626 | cpufreq_freq_attr_ro(bios_limit); |
| 627 | cpufreq_freq_attr_ro(related_cpus); |
| 628 | cpufreq_freq_attr_ro(affected_cpus); |
| 629 | cpufreq_freq_attr_rw(scaling_min_freq); |
| 630 | cpufreq_freq_attr_rw(scaling_max_freq); |
| 631 | cpufreq_freq_attr_rw(scaling_governor); |
| 632 | cpufreq_freq_attr_rw(scaling_setspeed); |
| 633 | |
| 634 | static struct attribute *default_attrs[] = { |
| 635 | &cpuinfo_min_freq.attr, |
| 636 | &cpuinfo_max_freq.attr, |
| 637 | &cpuinfo_transition_latency.attr, |
| 638 | &scaling_min_freq.attr, |
| 639 | &scaling_max_freq.attr, |
| 640 | &affected_cpus.attr, |
| 641 | &related_cpus.attr, |
| 642 | &scaling_governor.attr, |
| 643 | &scaling_driver.attr, |
| 644 | &scaling_available_governors.attr, |
| 645 | &scaling_setspeed.attr, |
| 646 | NULL |
| 647 | }; |
| 648 | |
| 649 | #define to_policy(k) container_of(k, struct cpufreq_policy, kobj) |
| 650 | #define to_attr(a) container_of(a, struct freq_attr, attr) |
| 651 | |
| 652 | static ssize_t show(struct kobject *kobj, struct attribute *attr, char *buf) |
| 653 | { |
| 654 | struct cpufreq_policy *policy = to_policy(kobj); |
| 655 | struct freq_attr *fattr = to_attr(attr); |
| 656 | ssize_t ret = -EINVAL; |
| 657 | |
| 658 | if (!down_read_trylock(&cpufreq_rwsem)) |
| 659 | goto exit; |
| 660 | |
| 661 | if (lock_policy_rwsem_read(policy->cpu) < 0) |
| 662 | goto up_read; |
| 663 | |
| 664 | if (fattr->show) |
| 665 | ret = fattr->show(policy, buf); |
| 666 | else |
| 667 | ret = -EIO; |
| 668 | |
| 669 | unlock_policy_rwsem_read(policy->cpu); |
| 670 | |
| 671 | up_read: |
| 672 | up_read(&cpufreq_rwsem); |
| 673 | exit: |
| 674 | return ret; |
| 675 | } |
| 676 | |
| 677 | static ssize_t store(struct kobject *kobj, struct attribute *attr, |
| 678 | const char *buf, size_t count) |
| 679 | { |
| 680 | struct cpufreq_policy *policy = to_policy(kobj); |
| 681 | struct freq_attr *fattr = to_attr(attr); |
| 682 | ssize_t ret = -EINVAL; |
| 683 | |
| 684 | get_online_cpus(); |
| 685 | |
| 686 | if (!cpu_online(policy->cpu)) |
| 687 | goto unlock; |
| 688 | |
| 689 | if (!down_read_trylock(&cpufreq_rwsem)) |
| 690 | goto unlock; |
| 691 | |
| 692 | if (lock_policy_rwsem_write(policy->cpu) < 0) |
| 693 | goto up_read; |
| 694 | |
| 695 | if (fattr->store) |
| 696 | ret = fattr->store(policy, buf, count); |
| 697 | else |
| 698 | ret = -EIO; |
| 699 | |
| 700 | unlock_policy_rwsem_write(policy->cpu); |
| 701 | |
| 702 | up_read: |
| 703 | up_read(&cpufreq_rwsem); |
| 704 | unlock: |
| 705 | put_online_cpus(); |
| 706 | |
| 707 | return ret; |
| 708 | } |
| 709 | |
| 710 | static void cpufreq_sysfs_release(struct kobject *kobj) |
| 711 | { |
| 712 | struct cpufreq_policy *policy = to_policy(kobj); |
| 713 | pr_debug("last reference is dropped\n"); |
| 714 | complete(&policy->kobj_unregister); |
| 715 | } |
| 716 | |
| 717 | static const struct sysfs_ops sysfs_ops = { |
| 718 | .show = show, |
| 719 | .store = store, |
| 720 | }; |
| 721 | |
| 722 | static struct kobj_type ktype_cpufreq = { |
| 723 | .sysfs_ops = &sysfs_ops, |
| 724 | .default_attrs = default_attrs, |
| 725 | .release = cpufreq_sysfs_release, |
| 726 | }; |
| 727 | |
| 728 | struct kobject *cpufreq_global_kobject; |
| 729 | EXPORT_SYMBOL(cpufreq_global_kobject); |
| 730 | |
| 731 | static int cpufreq_global_kobject_usage; |
| 732 | |
| 733 | int cpufreq_get_global_kobject(void) |
| 734 | { |
| 735 | if (!cpufreq_global_kobject_usage++) |
| 736 | return kobject_add(cpufreq_global_kobject, |
| 737 | &cpu_subsys.dev_root->kobj, "%s", "cpufreq"); |
| 738 | |
| 739 | return 0; |
| 740 | } |
| 741 | EXPORT_SYMBOL(cpufreq_get_global_kobject); |
| 742 | |
| 743 | void cpufreq_put_global_kobject(void) |
| 744 | { |
| 745 | if (!--cpufreq_global_kobject_usage) |
| 746 | kobject_del(cpufreq_global_kobject); |
| 747 | } |
| 748 | EXPORT_SYMBOL(cpufreq_put_global_kobject); |
| 749 | |
| 750 | int cpufreq_sysfs_create_file(const struct attribute *attr) |
| 751 | { |
| 752 | int ret = cpufreq_get_global_kobject(); |
| 753 | |
| 754 | if (!ret) { |
| 755 | ret = sysfs_create_file(cpufreq_global_kobject, attr); |
| 756 | if (ret) |
| 757 | cpufreq_put_global_kobject(); |
| 758 | } |
| 759 | |
| 760 | return ret; |
| 761 | } |
| 762 | EXPORT_SYMBOL(cpufreq_sysfs_create_file); |
| 763 | |
| 764 | void cpufreq_sysfs_remove_file(const struct attribute *attr) |
| 765 | { |
| 766 | sysfs_remove_file(cpufreq_global_kobject, attr); |
| 767 | cpufreq_put_global_kobject(); |
| 768 | } |
| 769 | EXPORT_SYMBOL(cpufreq_sysfs_remove_file); |
| 770 | |
| 771 | /* symlink affected CPUs */ |
| 772 | static int cpufreq_add_dev_symlink(struct cpufreq_policy *policy) |
| 773 | { |
| 774 | unsigned int j; |
| 775 | int ret = 0; |
| 776 | |
| 777 | for_each_cpu(j, policy->cpus) { |
| 778 | struct device *cpu_dev; |
| 779 | |
| 780 | if (j == policy->cpu) |
| 781 | continue; |
| 782 | |
| 783 | pr_debug("Adding link for CPU: %u\n", j); |
| 784 | cpu_dev = get_cpu_device(j); |
| 785 | ret = sysfs_create_link(&cpu_dev->kobj, &policy->kobj, |
| 786 | "cpufreq"); |
| 787 | if (ret) |
| 788 | break; |
| 789 | } |
| 790 | return ret; |
| 791 | } |
| 792 | |
| 793 | static int cpufreq_add_dev_interface(struct cpufreq_policy *policy, |
| 794 | struct device *dev) |
| 795 | { |
| 796 | struct freq_attr **drv_attr; |
| 797 | int ret = 0; |
| 798 | |
| 799 | /* prepare interface data */ |
| 800 | ret = kobject_init_and_add(&policy->kobj, &ktype_cpufreq, |
| 801 | &dev->kobj, "cpufreq"); |
| 802 | if (ret) |
| 803 | return ret; |
| 804 | |
| 805 | /* set up files for this cpu device */ |
| 806 | drv_attr = cpufreq_driver->attr; |
| 807 | while ((drv_attr) && (*drv_attr)) { |
| 808 | ret = sysfs_create_file(&policy->kobj, &((*drv_attr)->attr)); |
| 809 | if (ret) |
| 810 | goto err_out_kobj_put; |
| 811 | drv_attr++; |
| 812 | } |
| 813 | if (cpufreq_driver->get) { |
| 814 | ret = sysfs_create_file(&policy->kobj, &cpuinfo_cur_freq.attr); |
| 815 | if (ret) |
| 816 | goto err_out_kobj_put; |
| 817 | } |
| 818 | if (cpufreq_driver->target) { |
| 819 | ret = sysfs_create_file(&policy->kobj, &scaling_cur_freq.attr); |
| 820 | if (ret) |
| 821 | goto err_out_kobj_put; |
| 822 | } |
| 823 | if (cpufreq_driver->bios_limit) { |
| 824 | ret = sysfs_create_file(&policy->kobj, &bios_limit.attr); |
| 825 | if (ret) |
| 826 | goto err_out_kobj_put; |
| 827 | } |
| 828 | |
| 829 | ret = cpufreq_add_dev_symlink(policy); |
| 830 | if (ret) |
| 831 | goto err_out_kobj_put; |
| 832 | |
| 833 | return ret; |
| 834 | |
| 835 | err_out_kobj_put: |
| 836 | kobject_put(&policy->kobj); |
| 837 | wait_for_completion(&policy->kobj_unregister); |
| 838 | return ret; |
| 839 | } |
| 840 | |
| 841 | static void cpufreq_init_policy(struct cpufreq_policy *policy) |
| 842 | { |
| 843 | struct cpufreq_policy new_policy; |
| 844 | int ret = 0; |
| 845 | |
| 846 | memcpy(&new_policy, policy, sizeof(*policy)); |
| 847 | /* assure that the starting sequence is run in __cpufreq_set_policy */ |
| 848 | policy->governor = NULL; |
| 849 | |
| 850 | /* set default policy */ |
| 851 | ret = __cpufreq_set_policy(policy, &new_policy); |
| 852 | policy->user_policy.policy = policy->policy; |
| 853 | policy->user_policy.governor = policy->governor; |
| 854 | |
| 855 | if (ret) { |
| 856 | pr_debug("setting policy failed\n"); |
| 857 | if (cpufreq_driver->exit) |
| 858 | cpufreq_driver->exit(policy); |
| 859 | } |
| 860 | } |
| 861 | |
| 862 | #ifdef CONFIG_HOTPLUG_CPU |
| 863 | static int cpufreq_add_policy_cpu(struct cpufreq_policy *policy, |
| 864 | unsigned int cpu, struct device *dev, |
| 865 | bool frozen) |
| 866 | { |
| 867 | int ret = 0, has_target = !!cpufreq_driver->target; |
| 868 | unsigned long flags; |
| 869 | |
| 870 | if (has_target) { |
| 871 | ret = __cpufreq_governor(policy, CPUFREQ_GOV_STOP); |
| 872 | if (ret) { |
| 873 | pr_err("%s: Failed to stop governor\n", __func__); |
| 874 | return ret; |
| 875 | } |
| 876 | } |
| 877 | |
| 878 | lock_policy_rwsem_write(policy->cpu); |
| 879 | |
| 880 | write_lock_irqsave(&cpufreq_driver_lock, flags); |
| 881 | |
| 882 | cpumask_set_cpu(cpu, policy->cpus); |
| 883 | per_cpu(cpufreq_cpu_data, cpu) = policy; |
| 884 | write_unlock_irqrestore(&cpufreq_driver_lock, flags); |
| 885 | |
| 886 | unlock_policy_rwsem_write(policy->cpu); |
| 887 | |
| 888 | if (has_target) { |
| 889 | if ((ret = __cpufreq_governor(policy, CPUFREQ_GOV_START)) || |
| 890 | (ret = __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS))) { |
| 891 | pr_err("%s: Failed to start governor\n", __func__); |
| 892 | return ret; |
| 893 | } |
| 894 | } |
| 895 | |
| 896 | /* Don't touch sysfs links during light-weight init */ |
| 897 | if (!frozen) |
| 898 | ret = sysfs_create_link(&dev->kobj, &policy->kobj, "cpufreq"); |
| 899 | |
| 900 | return ret; |
| 901 | } |
| 902 | #endif |
| 903 | |
| 904 | static struct cpufreq_policy *cpufreq_policy_restore(unsigned int cpu) |
| 905 | { |
| 906 | struct cpufreq_policy *policy; |
| 907 | unsigned long flags; |
| 908 | |
| 909 | read_lock_irqsave(&cpufreq_driver_lock, flags); |
| 910 | |
| 911 | policy = per_cpu(cpufreq_cpu_data_fallback, cpu); |
| 912 | |
| 913 | read_unlock_irqrestore(&cpufreq_driver_lock, flags); |
| 914 | |
| 915 | return policy; |
| 916 | } |
| 917 | |
| 918 | static struct cpufreq_policy *cpufreq_policy_alloc(void) |
| 919 | { |
| 920 | struct cpufreq_policy *policy; |
| 921 | |
| 922 | policy = kzalloc(sizeof(*policy), GFP_KERNEL); |
| 923 | if (!policy) |
| 924 | return NULL; |
| 925 | |
| 926 | if (!alloc_cpumask_var(&policy->cpus, GFP_KERNEL)) |
| 927 | goto err_free_policy; |
| 928 | |
| 929 | if (!zalloc_cpumask_var(&policy->related_cpus, GFP_KERNEL)) |
| 930 | goto err_free_cpumask; |
| 931 | |
| 932 | INIT_LIST_HEAD(&policy->policy_list); |
| 933 | return policy; |
| 934 | |
| 935 | err_free_cpumask: |
| 936 | free_cpumask_var(policy->cpus); |
| 937 | err_free_policy: |
| 938 | kfree(policy); |
| 939 | |
| 940 | return NULL; |
| 941 | } |
| 942 | |
| 943 | static void cpufreq_policy_free(struct cpufreq_policy *policy) |
| 944 | { |
| 945 | free_cpumask_var(policy->related_cpus); |
| 946 | free_cpumask_var(policy->cpus); |
| 947 | kfree(policy); |
| 948 | } |
| 949 | |
| 950 | static void update_policy_cpu(struct cpufreq_policy *policy, unsigned int cpu) |
| 951 | { |
| 952 | if (cpu == policy->cpu) |
| 953 | return; |
| 954 | |
| 955 | /* |
| 956 | * Take direct locks as lock_policy_rwsem_write wouldn't work here. |
| 957 | * Also lock for last cpu is enough here as contention will happen only |
| 958 | * after policy->cpu is changed and after it is changed, other threads |
| 959 | * will try to acquire lock for new cpu. And policy is already updated |
| 960 | * by then. |
| 961 | */ |
| 962 | down_write(&per_cpu(cpu_policy_rwsem, policy->cpu)); |
| 963 | |
| 964 | policy->last_cpu = policy->cpu; |
| 965 | policy->cpu = cpu; |
| 966 | |
| 967 | up_write(&per_cpu(cpu_policy_rwsem, policy->last_cpu)); |
| 968 | |
| 969 | #ifdef CONFIG_CPU_FREQ_TABLE |
| 970 | cpufreq_frequency_table_update_policy_cpu(policy); |
| 971 | #endif |
| 972 | blocking_notifier_call_chain(&cpufreq_policy_notifier_list, |
| 973 | CPUFREQ_UPDATE_POLICY_CPU, policy); |
| 974 | } |
| 975 | |
| 976 | static int __cpufreq_add_dev(struct device *dev, struct subsys_interface *sif, |
| 977 | bool frozen) |
| 978 | { |
| 979 | unsigned int j, cpu = dev->id; |
| 980 | int ret = -ENOMEM; |
| 981 | struct cpufreq_policy *policy; |
| 982 | unsigned long flags; |
| 983 | #ifdef CONFIG_HOTPLUG_CPU |
| 984 | struct cpufreq_policy *tpolicy; |
| 985 | struct cpufreq_governor *gov; |
| 986 | #endif |
| 987 | |
| 988 | if (cpu_is_offline(cpu)) |
| 989 | return 0; |
| 990 | |
| 991 | pr_debug("adding CPU %u\n", cpu); |
| 992 | |
| 993 | #ifdef CONFIG_SMP |
| 994 | /* check whether a different CPU already registered this |
| 995 | * CPU because it is in the same boat. */ |
| 996 | policy = cpufreq_cpu_get(cpu); |
| 997 | if (unlikely(policy)) { |
| 998 | cpufreq_cpu_put(policy); |
| 999 | return 0; |
| 1000 | } |
| 1001 | #endif |
| 1002 | |
| 1003 | if (!down_read_trylock(&cpufreq_rwsem)) |
| 1004 | return 0; |
| 1005 | |
| 1006 | #ifdef CONFIG_HOTPLUG_CPU |
| 1007 | /* Check if this cpu was hot-unplugged earlier and has siblings */ |
| 1008 | read_lock_irqsave(&cpufreq_driver_lock, flags); |
| 1009 | list_for_each_entry(tpolicy, &cpufreq_policy_list, policy_list) { |
| 1010 | if (cpumask_test_cpu(cpu, tpolicy->related_cpus)) { |
| 1011 | read_unlock_irqrestore(&cpufreq_driver_lock, flags); |
| 1012 | ret = cpufreq_add_policy_cpu(tpolicy, cpu, dev, frozen); |
| 1013 | up_read(&cpufreq_rwsem); |
| 1014 | return ret; |
| 1015 | } |
| 1016 | } |
| 1017 | read_unlock_irqrestore(&cpufreq_driver_lock, flags); |
| 1018 | #endif |
| 1019 | |
| 1020 | if (frozen) |
| 1021 | /* Restore the saved policy when doing light-weight init */ |
| 1022 | policy = cpufreq_policy_restore(cpu); |
| 1023 | else |
| 1024 | policy = cpufreq_policy_alloc(); |
| 1025 | |
| 1026 | if (!policy) |
| 1027 | goto nomem_out; |
| 1028 | |
| 1029 | |
| 1030 | /* |
| 1031 | * In the resume path, since we restore a saved policy, the assignment |
| 1032 | * to policy->cpu is like an update of the existing policy, rather than |
| 1033 | * the creation of a brand new one. So we need to perform this update |
| 1034 | * by invoking update_policy_cpu(). |
| 1035 | */ |
| 1036 | if (frozen && cpu != policy->cpu) |
| 1037 | update_policy_cpu(policy, cpu); |
| 1038 | else |
| 1039 | policy->cpu = cpu; |
| 1040 | |
| 1041 | policy->governor = CPUFREQ_DEFAULT_GOVERNOR; |
| 1042 | cpumask_copy(policy->cpus, cpumask_of(cpu)); |
| 1043 | |
| 1044 | init_completion(&policy->kobj_unregister); |
| 1045 | INIT_WORK(&policy->update, handle_update); |
| 1046 | |
| 1047 | /* call driver. From then on the cpufreq must be able |
| 1048 | * to accept all calls to ->verify and ->setpolicy for this CPU |
| 1049 | */ |
| 1050 | ret = cpufreq_driver->init(policy); |
| 1051 | if (ret) { |
| 1052 | pr_debug("initialization failed\n"); |
| 1053 | goto err_set_policy_cpu; |
| 1054 | } |
| 1055 | |
| 1056 | /* related cpus should atleast have policy->cpus */ |
| 1057 | cpumask_or(policy->related_cpus, policy->related_cpus, policy->cpus); |
| 1058 | |
| 1059 | /* |
| 1060 | * affected cpus must always be the one, which are online. We aren't |
| 1061 | * managing offline cpus here. |
| 1062 | */ |
| 1063 | cpumask_and(policy->cpus, policy->cpus, cpu_online_mask); |
| 1064 | |
| 1065 | policy->user_policy.min = policy->min; |
| 1066 | policy->user_policy.max = policy->max; |
| 1067 | |
| 1068 | blocking_notifier_call_chain(&cpufreq_policy_notifier_list, |
| 1069 | CPUFREQ_START, policy); |
| 1070 | |
| 1071 | #ifdef CONFIG_HOTPLUG_CPU |
| 1072 | gov = __find_governor(per_cpu(cpufreq_cpu_governor, cpu)); |
| 1073 | if (gov) { |
| 1074 | policy->governor = gov; |
| 1075 | pr_debug("Restoring governor %s for cpu %d\n", |
| 1076 | policy->governor->name, cpu); |
| 1077 | } |
| 1078 | #endif |
| 1079 | |
| 1080 | write_lock_irqsave(&cpufreq_driver_lock, flags); |
| 1081 | for_each_cpu(j, policy->cpus) |
| 1082 | per_cpu(cpufreq_cpu_data, j) = policy; |
| 1083 | write_unlock_irqrestore(&cpufreq_driver_lock, flags); |
| 1084 | |
| 1085 | if (!frozen) { |
| 1086 | ret = cpufreq_add_dev_interface(policy, dev); |
| 1087 | if (ret) |
| 1088 | goto err_out_unregister; |
| 1089 | } |
| 1090 | |
| 1091 | write_lock_irqsave(&cpufreq_driver_lock, flags); |
| 1092 | list_add(&policy->policy_list, &cpufreq_policy_list); |
| 1093 | write_unlock_irqrestore(&cpufreq_driver_lock, flags); |
| 1094 | |
| 1095 | cpufreq_init_policy(policy); |
| 1096 | |
| 1097 | kobject_uevent(&policy->kobj, KOBJ_ADD); |
| 1098 | up_read(&cpufreq_rwsem); |
| 1099 | |
| 1100 | pr_debug("initialization complete\n"); |
| 1101 | |
| 1102 | return 0; |
| 1103 | |
| 1104 | err_out_unregister: |
| 1105 | write_lock_irqsave(&cpufreq_driver_lock, flags); |
| 1106 | for_each_cpu(j, policy->cpus) |
| 1107 | per_cpu(cpufreq_cpu_data, j) = NULL; |
| 1108 | write_unlock_irqrestore(&cpufreq_driver_lock, flags); |
| 1109 | |
| 1110 | err_set_policy_cpu: |
| 1111 | cpufreq_policy_free(policy); |
| 1112 | nomem_out: |
| 1113 | up_read(&cpufreq_rwsem); |
| 1114 | |
| 1115 | return ret; |
| 1116 | } |
| 1117 | |
| 1118 | /** |
| 1119 | * cpufreq_add_dev - add a CPU device |
| 1120 | * |
| 1121 | * Adds the cpufreq interface for a CPU device. |
| 1122 | * |
| 1123 | * The Oracle says: try running cpufreq registration/unregistration concurrently |
| 1124 | * with with cpu hotplugging and all hell will break loose. Tried to clean this |
| 1125 | * mess up, but more thorough testing is needed. - Mathieu |
| 1126 | */ |
| 1127 | static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif) |
| 1128 | { |
| 1129 | return __cpufreq_add_dev(dev, sif, false); |
| 1130 | } |
| 1131 | |
| 1132 | static int cpufreq_nominate_new_policy_cpu(struct cpufreq_policy *policy, |
| 1133 | unsigned int old_cpu, bool frozen) |
| 1134 | { |
| 1135 | struct device *cpu_dev; |
| 1136 | int ret; |
| 1137 | |
| 1138 | /* first sibling now owns the new sysfs dir */ |
| 1139 | cpu_dev = get_cpu_device(cpumask_any_but(policy->cpus, old_cpu)); |
| 1140 | |
| 1141 | /* Don't touch sysfs files during light-weight tear-down */ |
| 1142 | if (frozen) |
| 1143 | return cpu_dev->id; |
| 1144 | |
| 1145 | sysfs_remove_link(&cpu_dev->kobj, "cpufreq"); |
| 1146 | ret = kobject_move(&policy->kobj, &cpu_dev->kobj); |
| 1147 | if (ret) { |
| 1148 | pr_err("%s: Failed to move kobj: %d", __func__, ret); |
| 1149 | |
| 1150 | WARN_ON(lock_policy_rwsem_write(old_cpu)); |
| 1151 | cpumask_set_cpu(old_cpu, policy->cpus); |
| 1152 | unlock_policy_rwsem_write(old_cpu); |
| 1153 | |
| 1154 | ret = sysfs_create_link(&cpu_dev->kobj, &policy->kobj, |
| 1155 | "cpufreq"); |
| 1156 | |
| 1157 | return -EINVAL; |
| 1158 | } |
| 1159 | |
| 1160 | return cpu_dev->id; |
| 1161 | } |
| 1162 | |
| 1163 | static int __cpufreq_remove_dev_prepare(struct device *dev, |
| 1164 | struct subsys_interface *sif, |
| 1165 | bool frozen) |
| 1166 | { |
| 1167 | unsigned int cpu = dev->id, cpus; |
| 1168 | int new_cpu, ret; |
| 1169 | unsigned long flags; |
| 1170 | struct cpufreq_policy *policy; |
| 1171 | |
| 1172 | pr_debug("%s: unregistering CPU %u\n", __func__, cpu); |
| 1173 | |
| 1174 | write_lock_irqsave(&cpufreq_driver_lock, flags); |
| 1175 | |
| 1176 | policy = per_cpu(cpufreq_cpu_data, cpu); |
| 1177 | |
| 1178 | /* Save the policy somewhere when doing a light-weight tear-down */ |
| 1179 | if (frozen) |
| 1180 | per_cpu(cpufreq_cpu_data_fallback, cpu) = policy; |
| 1181 | |
| 1182 | write_unlock_irqrestore(&cpufreq_driver_lock, flags); |
| 1183 | |
| 1184 | if (!policy) { |
| 1185 | pr_debug("%s: No cpu_data found\n", __func__); |
| 1186 | return -EINVAL; |
| 1187 | } |
| 1188 | |
| 1189 | if (cpufreq_driver->target) { |
| 1190 | ret = __cpufreq_governor(policy, CPUFREQ_GOV_STOP); |
| 1191 | if (ret) { |
| 1192 | pr_err("%s: Failed to stop governor\n", __func__); |
| 1193 | return ret; |
| 1194 | } |
| 1195 | } |
| 1196 | |
| 1197 | #ifdef CONFIG_HOTPLUG_CPU |
| 1198 | if (!cpufreq_driver->setpolicy) |
| 1199 | strncpy(per_cpu(cpufreq_cpu_governor, cpu), |
| 1200 | policy->governor->name, CPUFREQ_NAME_LEN); |
| 1201 | #endif |
| 1202 | |
| 1203 | lock_policy_rwsem_read(cpu); |
| 1204 | cpus = cpumask_weight(policy->cpus); |
| 1205 | unlock_policy_rwsem_read(cpu); |
| 1206 | |
| 1207 | if (cpu != policy->cpu) { |
| 1208 | if (!frozen) |
| 1209 | sysfs_remove_link(&dev->kobj, "cpufreq"); |
| 1210 | } else if (cpus > 1) { |
| 1211 | |
| 1212 | new_cpu = cpufreq_nominate_new_policy_cpu(policy, cpu, frozen); |
| 1213 | if (new_cpu >= 0) { |
| 1214 | update_policy_cpu(policy, new_cpu); |
| 1215 | |
| 1216 | if (!frozen) { |
| 1217 | pr_debug("%s: policy Kobject moved to cpu: %d " |
| 1218 | "from: %d\n",__func__, new_cpu, cpu); |
| 1219 | } |
| 1220 | } |
| 1221 | } |
| 1222 | |
| 1223 | return 0; |
| 1224 | } |
| 1225 | |
| 1226 | static int __cpufreq_remove_dev_finish(struct device *dev, |
| 1227 | struct subsys_interface *sif, |
| 1228 | bool frozen) |
| 1229 | { |
| 1230 | unsigned int cpu = dev->id, cpus; |
| 1231 | int ret; |
| 1232 | unsigned long flags; |
| 1233 | struct cpufreq_policy *policy; |
| 1234 | struct kobject *kobj; |
| 1235 | struct completion *cmp; |
| 1236 | |
| 1237 | read_lock_irqsave(&cpufreq_driver_lock, flags); |
| 1238 | policy = per_cpu(cpufreq_cpu_data, cpu); |
| 1239 | read_unlock_irqrestore(&cpufreq_driver_lock, flags); |
| 1240 | |
| 1241 | if (!policy) { |
| 1242 | pr_debug("%s: No cpu_data found\n", __func__); |
| 1243 | return -EINVAL; |
| 1244 | } |
| 1245 | |
| 1246 | WARN_ON(lock_policy_rwsem_write(cpu)); |
| 1247 | cpus = cpumask_weight(policy->cpus); |
| 1248 | |
| 1249 | if (cpus > 1) |
| 1250 | cpumask_clear_cpu(cpu, policy->cpus); |
| 1251 | unlock_policy_rwsem_write(cpu); |
| 1252 | |
| 1253 | /* If cpu is last user of policy, free policy */ |
| 1254 | if (cpus == 1) { |
| 1255 | if (cpufreq_driver->target) { |
| 1256 | ret = __cpufreq_governor(policy, |
| 1257 | CPUFREQ_GOV_POLICY_EXIT); |
| 1258 | if (ret) { |
| 1259 | pr_err("%s: Failed to exit governor\n", |
| 1260 | __func__); |
| 1261 | return ret; |
| 1262 | } |
| 1263 | } |
| 1264 | |
| 1265 | if (!frozen) { |
| 1266 | lock_policy_rwsem_read(cpu); |
| 1267 | kobj = &policy->kobj; |
| 1268 | cmp = &policy->kobj_unregister; |
| 1269 | unlock_policy_rwsem_read(cpu); |
| 1270 | kobject_put(kobj); |
| 1271 | |
| 1272 | /* |
| 1273 | * We need to make sure that the underlying kobj is |
| 1274 | * actually not referenced anymore by anybody before we |
| 1275 | * proceed with unloading. |
| 1276 | */ |
| 1277 | pr_debug("waiting for dropping of refcount\n"); |
| 1278 | wait_for_completion(cmp); |
| 1279 | pr_debug("wait complete\n"); |
| 1280 | } |
| 1281 | |
| 1282 | /* |
| 1283 | * Perform the ->exit() even during light-weight tear-down, |
| 1284 | * since this is a core component, and is essential for the |
| 1285 | * subsequent light-weight ->init() to succeed. |
| 1286 | */ |
| 1287 | if (cpufreq_driver->exit) |
| 1288 | cpufreq_driver->exit(policy); |
| 1289 | |
| 1290 | /* Remove policy from list of active policies */ |
| 1291 | write_lock_irqsave(&cpufreq_driver_lock, flags); |
| 1292 | list_del(&policy->policy_list); |
| 1293 | write_unlock_irqrestore(&cpufreq_driver_lock, flags); |
| 1294 | |
| 1295 | if (!frozen) |
| 1296 | cpufreq_policy_free(policy); |
| 1297 | } else { |
| 1298 | if (cpufreq_driver->target) { |
| 1299 | if ((ret = __cpufreq_governor(policy, CPUFREQ_GOV_START)) || |
| 1300 | (ret = __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS))) { |
| 1301 | pr_err("%s: Failed to start governor\n", |
| 1302 | __func__); |
| 1303 | return ret; |
| 1304 | } |
| 1305 | } |
| 1306 | } |
| 1307 | |
| 1308 | per_cpu(cpufreq_cpu_data, cpu) = NULL; |
| 1309 | return 0; |
| 1310 | } |
| 1311 | |
| 1312 | /** |
| 1313 | * __cpufreq_remove_dev - remove a CPU device |
| 1314 | * |
| 1315 | * Removes the cpufreq interface for a CPU device. |
| 1316 | * Caller should already have policy_rwsem in write mode for this CPU. |
| 1317 | * This routine frees the rwsem before returning. |
| 1318 | */ |
| 1319 | static inline int __cpufreq_remove_dev(struct device *dev, |
| 1320 | struct subsys_interface *sif, |
| 1321 | bool frozen) |
| 1322 | { |
| 1323 | int ret; |
| 1324 | |
| 1325 | ret = __cpufreq_remove_dev_prepare(dev, sif, frozen); |
| 1326 | |
| 1327 | if (!ret) |
| 1328 | ret = __cpufreq_remove_dev_finish(dev, sif, frozen); |
| 1329 | |
| 1330 | return ret; |
| 1331 | } |
| 1332 | |
| 1333 | static int cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif) |
| 1334 | { |
| 1335 | unsigned int cpu = dev->id; |
| 1336 | int retval; |
| 1337 | |
| 1338 | if (cpu_is_offline(cpu)) |
| 1339 | return 0; |
| 1340 | |
| 1341 | retval = __cpufreq_remove_dev(dev, sif, false); |
| 1342 | return retval; |
| 1343 | } |
| 1344 | |
| 1345 | static void handle_update(struct work_struct *work) |
| 1346 | { |
| 1347 | struct cpufreq_policy *policy = |
| 1348 | container_of(work, struct cpufreq_policy, update); |
| 1349 | unsigned int cpu = policy->cpu; |
| 1350 | pr_debug("handle_update for cpu %u called\n", cpu); |
| 1351 | cpufreq_update_policy(cpu); |
| 1352 | } |
| 1353 | |
| 1354 | /** |
| 1355 | * cpufreq_out_of_sync - If actual and saved CPU frequency differs, we're |
| 1356 | * in deep trouble. |
| 1357 | * @cpu: cpu number |
| 1358 | * @old_freq: CPU frequency the kernel thinks the CPU runs at |
| 1359 | * @new_freq: CPU frequency the CPU actually runs at |
| 1360 | * |
| 1361 | * We adjust to current frequency first, and need to clean up later. |
| 1362 | * So either call to cpufreq_update_policy() or schedule handle_update()). |
| 1363 | */ |
| 1364 | static void cpufreq_out_of_sync(unsigned int cpu, unsigned int old_freq, |
| 1365 | unsigned int new_freq) |
| 1366 | { |
| 1367 | struct cpufreq_policy *policy; |
| 1368 | struct cpufreq_freqs freqs; |
| 1369 | unsigned long flags; |
| 1370 | |
| 1371 | pr_debug("Warning: CPU frequency out of sync: cpufreq and timing " |
| 1372 | "core thinks of %u, is %u kHz.\n", old_freq, new_freq); |
| 1373 | |
| 1374 | freqs.old = old_freq; |
| 1375 | freqs.new = new_freq; |
| 1376 | |
| 1377 | read_lock_irqsave(&cpufreq_driver_lock, flags); |
| 1378 | policy = per_cpu(cpufreq_cpu_data, cpu); |
| 1379 | read_unlock_irqrestore(&cpufreq_driver_lock, flags); |
| 1380 | |
| 1381 | cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE); |
| 1382 | cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE); |
| 1383 | } |
| 1384 | |
| 1385 | /** |
| 1386 | * cpufreq_quick_get - get the CPU frequency (in kHz) from policy->cur |
| 1387 | * @cpu: CPU number |
| 1388 | * |
| 1389 | * This is the last known freq, without actually getting it from the driver. |
| 1390 | * Return value will be same as what is shown in scaling_cur_freq in sysfs. |
| 1391 | */ |
| 1392 | unsigned int cpufreq_quick_get(unsigned int cpu) |
| 1393 | { |
| 1394 | struct cpufreq_policy *policy; |
| 1395 | unsigned int ret_freq = 0; |
| 1396 | |
| 1397 | if (cpufreq_driver && cpufreq_driver->setpolicy && cpufreq_driver->get) |
| 1398 | return cpufreq_driver->get(cpu); |
| 1399 | |
| 1400 | policy = cpufreq_cpu_get(cpu); |
| 1401 | if (policy) { |
| 1402 | ret_freq = policy->cur; |
| 1403 | cpufreq_cpu_put(policy); |
| 1404 | } |
| 1405 | |
| 1406 | return ret_freq; |
| 1407 | } |
| 1408 | EXPORT_SYMBOL(cpufreq_quick_get); |
| 1409 | |
| 1410 | /** |
| 1411 | * cpufreq_quick_get_max - get the max reported CPU frequency for this CPU |
| 1412 | * @cpu: CPU number |
| 1413 | * |
| 1414 | * Just return the max possible frequency for a given CPU. |
| 1415 | */ |
| 1416 | unsigned int cpufreq_quick_get_max(unsigned int cpu) |
| 1417 | { |
| 1418 | struct cpufreq_policy *policy = cpufreq_cpu_get(cpu); |
| 1419 | unsigned int ret_freq = 0; |
| 1420 | |
| 1421 | if (policy) { |
| 1422 | ret_freq = policy->max; |
| 1423 | cpufreq_cpu_put(policy); |
| 1424 | } |
| 1425 | |
| 1426 | return ret_freq; |
| 1427 | } |
| 1428 | EXPORT_SYMBOL(cpufreq_quick_get_max); |
| 1429 | |
| 1430 | static unsigned int __cpufreq_get(unsigned int cpu) |
| 1431 | { |
| 1432 | struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu); |
| 1433 | unsigned int ret_freq = 0; |
| 1434 | |
| 1435 | if (!cpufreq_driver->get) |
| 1436 | return ret_freq; |
| 1437 | |
| 1438 | ret_freq = cpufreq_driver->get(cpu); |
| 1439 | |
| 1440 | if (ret_freq && policy->cur && |
| 1441 | !(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) { |
| 1442 | /* verify no discrepancy between actual and |
| 1443 | saved value exists */ |
| 1444 | if (unlikely(ret_freq != policy->cur)) { |
| 1445 | cpufreq_out_of_sync(cpu, policy->cur, ret_freq); |
| 1446 | schedule_work(&policy->update); |
| 1447 | } |
| 1448 | } |
| 1449 | |
| 1450 | return ret_freq; |
| 1451 | } |
| 1452 | |
| 1453 | /** |
| 1454 | * cpufreq_get - get the current CPU frequency (in kHz) |
| 1455 | * @cpu: CPU number |
| 1456 | * |
| 1457 | * Get the CPU current (static) CPU frequency |
| 1458 | */ |
| 1459 | unsigned int cpufreq_get(unsigned int cpu) |
| 1460 | { |
| 1461 | unsigned int ret_freq = 0; |
| 1462 | |
| 1463 | if (cpufreq_disabled() || !cpufreq_driver) |
| 1464 | return -ENOENT; |
| 1465 | |
| 1466 | if (!down_read_trylock(&cpufreq_rwsem)) |
| 1467 | return 0; |
| 1468 | |
| 1469 | if (unlikely(lock_policy_rwsem_read(cpu))) |
| 1470 | goto out_policy; |
| 1471 | |
| 1472 | ret_freq = __cpufreq_get(cpu); |
| 1473 | |
| 1474 | unlock_policy_rwsem_read(cpu); |
| 1475 | |
| 1476 | out_policy: |
| 1477 | up_read(&cpufreq_rwsem); |
| 1478 | |
| 1479 | return ret_freq; |
| 1480 | } |
| 1481 | EXPORT_SYMBOL(cpufreq_get); |
| 1482 | |
| 1483 | static struct subsys_interface cpufreq_interface = { |
| 1484 | .name = "cpufreq", |
| 1485 | .subsys = &cpu_subsys, |
| 1486 | .add_dev = cpufreq_add_dev, |
| 1487 | .remove_dev = cpufreq_remove_dev, |
| 1488 | }; |
| 1489 | |
| 1490 | /** |
| 1491 | * cpufreq_bp_suspend - Prepare the boot CPU for system suspend. |
| 1492 | * |
| 1493 | * This function is only executed for the boot processor. The other CPUs |
| 1494 | * have been put offline by means of CPU hotplug. |
| 1495 | */ |
| 1496 | static int cpufreq_bp_suspend(void) |
| 1497 | { |
| 1498 | int ret = 0; |
| 1499 | |
| 1500 | int cpu = smp_processor_id(); |
| 1501 | struct cpufreq_policy *policy; |
| 1502 | |
| 1503 | pr_debug("suspending cpu %u\n", cpu); |
| 1504 | |
| 1505 | /* If there's no policy for the boot CPU, we have nothing to do. */ |
| 1506 | policy = cpufreq_cpu_get(cpu); |
| 1507 | if (!policy) |
| 1508 | return 0; |
| 1509 | |
| 1510 | if (cpufreq_driver->suspend) { |
| 1511 | ret = cpufreq_driver->suspend(policy); |
| 1512 | if (ret) |
| 1513 | printk(KERN_ERR "cpufreq: suspend failed in ->suspend " |
| 1514 | "step on CPU %u\n", policy->cpu); |
| 1515 | } |
| 1516 | |
| 1517 | cpufreq_cpu_put(policy); |
| 1518 | return ret; |
| 1519 | } |
| 1520 | |
| 1521 | /** |
| 1522 | * cpufreq_bp_resume - Restore proper frequency handling of the boot CPU. |
| 1523 | * |
| 1524 | * 1.) resume CPUfreq hardware support (cpufreq_driver->resume()) |
| 1525 | * 2.) schedule call cpufreq_update_policy() ASAP as interrupts are |
| 1526 | * restored. It will verify that the current freq is in sync with |
| 1527 | * what we believe it to be. This is a bit later than when it |
| 1528 | * should be, but nonethteless it's better than calling |
| 1529 | * cpufreq_driver->get() here which might re-enable interrupts... |
| 1530 | * |
| 1531 | * This function is only executed for the boot CPU. The other CPUs have not |
| 1532 | * been turned on yet. |
| 1533 | */ |
| 1534 | static void cpufreq_bp_resume(void) |
| 1535 | { |
| 1536 | int ret = 0; |
| 1537 | |
| 1538 | int cpu = smp_processor_id(); |
| 1539 | struct cpufreq_policy *policy; |
| 1540 | |
| 1541 | pr_debug("resuming cpu %u\n", cpu); |
| 1542 | |
| 1543 | /* If there's no policy for the boot CPU, we have nothing to do. */ |
| 1544 | policy = cpufreq_cpu_get(cpu); |
| 1545 | if (!policy) |
| 1546 | return; |
| 1547 | |
| 1548 | if (cpufreq_driver->resume) { |
| 1549 | ret = cpufreq_driver->resume(policy); |
| 1550 | if (ret) { |
| 1551 | printk(KERN_ERR "cpufreq: resume failed in ->resume " |
| 1552 | "step on CPU %u\n", policy->cpu); |
| 1553 | goto fail; |
| 1554 | } |
| 1555 | } |
| 1556 | |
| 1557 | schedule_work(&policy->update); |
| 1558 | |
| 1559 | fail: |
| 1560 | cpufreq_cpu_put(policy); |
| 1561 | } |
| 1562 | |
| 1563 | static struct syscore_ops cpufreq_syscore_ops = { |
| 1564 | .suspend = cpufreq_bp_suspend, |
| 1565 | .resume = cpufreq_bp_resume, |
| 1566 | }; |
| 1567 | |
| 1568 | /** |
| 1569 | * cpufreq_get_current_driver - return current driver's name |
| 1570 | * |
| 1571 | * Return the name string of the currently loaded cpufreq driver |
| 1572 | * or NULL, if none. |
| 1573 | */ |
| 1574 | const char *cpufreq_get_current_driver(void) |
| 1575 | { |
| 1576 | if (cpufreq_driver) |
| 1577 | return cpufreq_driver->name; |
| 1578 | |
| 1579 | return NULL; |
| 1580 | } |
| 1581 | EXPORT_SYMBOL_GPL(cpufreq_get_current_driver); |
| 1582 | |
| 1583 | /********************************************************************* |
| 1584 | * NOTIFIER LISTS INTERFACE * |
| 1585 | *********************************************************************/ |
| 1586 | |
| 1587 | /** |
| 1588 | * cpufreq_register_notifier - register a driver with cpufreq |
| 1589 | * @nb: notifier function to register |
| 1590 | * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER |
| 1591 | * |
| 1592 | * Add a driver to one of two lists: either a list of drivers that |
| 1593 | * are notified about clock rate changes (once before and once after |
| 1594 | * the transition), or a list of drivers that are notified about |
| 1595 | * changes in cpufreq policy. |
| 1596 | * |
| 1597 | * This function may sleep, and has the same return conditions as |
| 1598 | * blocking_notifier_chain_register. |
| 1599 | */ |
| 1600 | int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list) |
| 1601 | { |
| 1602 | int ret; |
| 1603 | |
| 1604 | if (cpufreq_disabled()) |
| 1605 | return -EINVAL; |
| 1606 | |
| 1607 | WARN_ON(!init_cpufreq_transition_notifier_list_called); |
| 1608 | |
| 1609 | switch (list) { |
| 1610 | case CPUFREQ_TRANSITION_NOTIFIER: |
| 1611 | ret = srcu_notifier_chain_register( |
| 1612 | &cpufreq_transition_notifier_list, nb); |
| 1613 | break; |
| 1614 | case CPUFREQ_POLICY_NOTIFIER: |
| 1615 | ret = blocking_notifier_chain_register( |
| 1616 | &cpufreq_policy_notifier_list, nb); |
| 1617 | break; |
| 1618 | default: |
| 1619 | ret = -EINVAL; |
| 1620 | } |
| 1621 | |
| 1622 | return ret; |
| 1623 | } |
| 1624 | EXPORT_SYMBOL(cpufreq_register_notifier); |
| 1625 | |
| 1626 | /** |
| 1627 | * cpufreq_unregister_notifier - unregister a driver with cpufreq |
| 1628 | * @nb: notifier block to be unregistered |
| 1629 | * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER |
| 1630 | * |
| 1631 | * Remove a driver from the CPU frequency notifier list. |
| 1632 | * |
| 1633 | * This function may sleep, and has the same return conditions as |
| 1634 | * blocking_notifier_chain_unregister. |
| 1635 | */ |
| 1636 | int cpufreq_unregister_notifier(struct notifier_block *nb, unsigned int list) |
| 1637 | { |
| 1638 | int ret; |
| 1639 | |
| 1640 | if (cpufreq_disabled()) |
| 1641 | return -EINVAL; |
| 1642 | |
| 1643 | switch (list) { |
| 1644 | case CPUFREQ_TRANSITION_NOTIFIER: |
| 1645 | ret = srcu_notifier_chain_unregister( |
| 1646 | &cpufreq_transition_notifier_list, nb); |
| 1647 | break; |
| 1648 | case CPUFREQ_POLICY_NOTIFIER: |
| 1649 | ret = blocking_notifier_chain_unregister( |
| 1650 | &cpufreq_policy_notifier_list, nb); |
| 1651 | break; |
| 1652 | default: |
| 1653 | ret = -EINVAL; |
| 1654 | } |
| 1655 | |
| 1656 | return ret; |
| 1657 | } |
| 1658 | EXPORT_SYMBOL(cpufreq_unregister_notifier); |
| 1659 | |
| 1660 | |
| 1661 | /********************************************************************* |
| 1662 | * GOVERNORS * |
| 1663 | *********************************************************************/ |
| 1664 | |
| 1665 | int __cpufreq_driver_target(struct cpufreq_policy *policy, |
| 1666 | unsigned int target_freq, |
| 1667 | unsigned int relation) |
| 1668 | { |
| 1669 | int retval = -EINVAL; |
| 1670 | unsigned int old_target_freq = target_freq; |
| 1671 | |
| 1672 | if (cpufreq_disabled()) |
| 1673 | return -ENODEV; |
| 1674 | |
| 1675 | /* Make sure that target_freq is within supported range */ |
| 1676 | if (target_freq > policy->max) |
| 1677 | target_freq = policy->max; |
| 1678 | if (target_freq < policy->min) |
| 1679 | target_freq = policy->min; |
| 1680 | |
| 1681 | pr_debug("target for CPU %u: %u kHz, relation %u, requested %u kHz\n", |
| 1682 | policy->cpu, target_freq, relation, old_target_freq); |
| 1683 | |
| 1684 | if (target_freq == policy->cur) |
| 1685 | return 0; |
| 1686 | |
| 1687 | if (cpufreq_driver->target) |
| 1688 | retval = cpufreq_driver->target(policy, target_freq, relation); |
| 1689 | |
| 1690 | return retval; |
| 1691 | } |
| 1692 | EXPORT_SYMBOL_GPL(__cpufreq_driver_target); |
| 1693 | |
| 1694 | int cpufreq_driver_target(struct cpufreq_policy *policy, |
| 1695 | unsigned int target_freq, |
| 1696 | unsigned int relation) |
| 1697 | { |
| 1698 | int ret = -EINVAL; |
| 1699 | |
| 1700 | if (unlikely(lock_policy_rwsem_write(policy->cpu))) |
| 1701 | goto fail; |
| 1702 | |
| 1703 | ret = __cpufreq_driver_target(policy, target_freq, relation); |
| 1704 | |
| 1705 | unlock_policy_rwsem_write(policy->cpu); |
| 1706 | |
| 1707 | fail: |
| 1708 | return ret; |
| 1709 | } |
| 1710 | EXPORT_SYMBOL_GPL(cpufreq_driver_target); |
| 1711 | |
| 1712 | /* |
| 1713 | * when "event" is CPUFREQ_GOV_LIMITS |
| 1714 | */ |
| 1715 | |
| 1716 | static int __cpufreq_governor(struct cpufreq_policy *policy, |
| 1717 | unsigned int event) |
| 1718 | { |
| 1719 | int ret; |
| 1720 | |
| 1721 | /* Only must be defined when default governor is known to have latency |
| 1722 | restrictions, like e.g. conservative or ondemand. |
| 1723 | That this is the case is already ensured in Kconfig |
| 1724 | */ |
| 1725 | #ifdef CONFIG_CPU_FREQ_GOV_PERFORMANCE |
| 1726 | struct cpufreq_governor *gov = &cpufreq_gov_performance; |
| 1727 | #else |
| 1728 | struct cpufreq_governor *gov = NULL; |
| 1729 | #endif |
| 1730 | |
| 1731 | if (policy->governor->max_transition_latency && |
| 1732 | policy->cpuinfo.transition_latency > |
| 1733 | policy->governor->max_transition_latency) { |
| 1734 | if (!gov) |
| 1735 | return -EINVAL; |
| 1736 | else { |
| 1737 | printk(KERN_WARNING "%s governor failed, too long" |
| 1738 | " transition latency of HW, fallback" |
| 1739 | " to %s governor\n", |
| 1740 | policy->governor->name, |
| 1741 | gov->name); |
| 1742 | policy->governor = gov; |
| 1743 | } |
| 1744 | } |
| 1745 | |
| 1746 | if (event == CPUFREQ_GOV_POLICY_INIT) |
| 1747 | if (!try_module_get(policy->governor->owner)) |
| 1748 | return -EINVAL; |
| 1749 | |
| 1750 | pr_debug("__cpufreq_governor for CPU %u, event %u\n", |
| 1751 | policy->cpu, event); |
| 1752 | |
| 1753 | mutex_lock(&cpufreq_governor_lock); |
| 1754 | if ((policy->governor_enabled && event == CPUFREQ_GOV_START) |
| 1755 | || (!policy->governor_enabled |
| 1756 | && (event == CPUFREQ_GOV_LIMITS || event == CPUFREQ_GOV_STOP))) { |
| 1757 | mutex_unlock(&cpufreq_governor_lock); |
| 1758 | return -EBUSY; |
| 1759 | } |
| 1760 | |
| 1761 | if (event == CPUFREQ_GOV_STOP) |
| 1762 | policy->governor_enabled = false; |
| 1763 | else if (event == CPUFREQ_GOV_START) |
| 1764 | policy->governor_enabled = true; |
| 1765 | |
| 1766 | mutex_unlock(&cpufreq_governor_lock); |
| 1767 | |
| 1768 | ret = policy->governor->governor(policy, event); |
| 1769 | |
| 1770 | if (!ret) { |
| 1771 | if (event == CPUFREQ_GOV_POLICY_INIT) |
| 1772 | policy->governor->initialized++; |
| 1773 | else if (event == CPUFREQ_GOV_POLICY_EXIT) |
| 1774 | policy->governor->initialized--; |
| 1775 | } else { |
| 1776 | /* Restore original values */ |
| 1777 | mutex_lock(&cpufreq_governor_lock); |
| 1778 | if (event == CPUFREQ_GOV_STOP) |
| 1779 | policy->governor_enabled = true; |
| 1780 | else if (event == CPUFREQ_GOV_START) |
| 1781 | policy->governor_enabled = false; |
| 1782 | mutex_unlock(&cpufreq_governor_lock); |
| 1783 | } |
| 1784 | |
| 1785 | if (((event == CPUFREQ_GOV_POLICY_INIT) && ret) || |
| 1786 | ((event == CPUFREQ_GOV_POLICY_EXIT) && !ret)) |
| 1787 | module_put(policy->governor->owner); |
| 1788 | |
| 1789 | return ret; |
| 1790 | } |
| 1791 | |
| 1792 | int cpufreq_register_governor(struct cpufreq_governor *governor) |
| 1793 | { |
| 1794 | int err; |
| 1795 | |
| 1796 | if (!governor) |
| 1797 | return -EINVAL; |
| 1798 | |
| 1799 | if (cpufreq_disabled()) |
| 1800 | return -ENODEV; |
| 1801 | |
| 1802 | mutex_lock(&cpufreq_governor_mutex); |
| 1803 | |
| 1804 | governor->initialized = 0; |
| 1805 | err = -EBUSY; |
| 1806 | if (__find_governor(governor->name) == NULL) { |
| 1807 | err = 0; |
| 1808 | list_add(&governor->governor_list, &cpufreq_governor_list); |
| 1809 | } |
| 1810 | |
| 1811 | mutex_unlock(&cpufreq_governor_mutex); |
| 1812 | return err; |
| 1813 | } |
| 1814 | EXPORT_SYMBOL_GPL(cpufreq_register_governor); |
| 1815 | |
| 1816 | void cpufreq_unregister_governor(struct cpufreq_governor *governor) |
| 1817 | { |
| 1818 | #ifdef CONFIG_HOTPLUG_CPU |
| 1819 | int cpu; |
| 1820 | #endif |
| 1821 | |
| 1822 | if (!governor) |
| 1823 | return; |
| 1824 | |
| 1825 | if (cpufreq_disabled()) |
| 1826 | return; |
| 1827 | |
| 1828 | #ifdef CONFIG_HOTPLUG_CPU |
| 1829 | for_each_present_cpu(cpu) { |
| 1830 | if (cpu_online(cpu)) |
| 1831 | continue; |
| 1832 | if (!strcmp(per_cpu(cpufreq_cpu_governor, cpu), governor->name)) |
| 1833 | strcpy(per_cpu(cpufreq_cpu_governor, cpu), "\0"); |
| 1834 | } |
| 1835 | #endif |
| 1836 | |
| 1837 | mutex_lock(&cpufreq_governor_mutex); |
| 1838 | list_del(&governor->governor_list); |
| 1839 | mutex_unlock(&cpufreq_governor_mutex); |
| 1840 | return; |
| 1841 | } |
| 1842 | EXPORT_SYMBOL_GPL(cpufreq_unregister_governor); |
| 1843 | |
| 1844 | |
| 1845 | /********************************************************************* |
| 1846 | * POLICY INTERFACE * |
| 1847 | *********************************************************************/ |
| 1848 | |
| 1849 | /** |
| 1850 | * cpufreq_get_policy - get the current cpufreq_policy |
| 1851 | * @policy: struct cpufreq_policy into which the current cpufreq_policy |
| 1852 | * is written |
| 1853 | * |
| 1854 | * Reads the current cpufreq policy. |
| 1855 | */ |
| 1856 | int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu) |
| 1857 | { |
| 1858 | struct cpufreq_policy *cpu_policy; |
| 1859 | if (!policy) |
| 1860 | return -EINVAL; |
| 1861 | |
| 1862 | cpu_policy = cpufreq_cpu_get(cpu); |
| 1863 | if (!cpu_policy) |
| 1864 | return -EINVAL; |
| 1865 | |
| 1866 | memcpy(policy, cpu_policy, sizeof(*policy)); |
| 1867 | |
| 1868 | cpufreq_cpu_put(cpu_policy); |
| 1869 | return 0; |
| 1870 | } |
| 1871 | EXPORT_SYMBOL(cpufreq_get_policy); |
| 1872 | |
| 1873 | /* |
| 1874 | * data : current policy. |
| 1875 | * policy : policy to be set. |
| 1876 | */ |
| 1877 | static int __cpufreq_set_policy(struct cpufreq_policy *policy, |
| 1878 | struct cpufreq_policy *new_policy) |
| 1879 | { |
| 1880 | int ret = 0, failed = 1; |
| 1881 | |
| 1882 | pr_debug("setting new policy for CPU %u: %u - %u kHz\n", new_policy->cpu, |
| 1883 | new_policy->min, new_policy->max); |
| 1884 | |
| 1885 | memcpy(&new_policy->cpuinfo, &policy->cpuinfo, sizeof(policy->cpuinfo)); |
| 1886 | |
| 1887 | if (new_policy->min > policy->max || new_policy->max < policy->min) { |
| 1888 | ret = -EINVAL; |
| 1889 | goto error_out; |
| 1890 | } |
| 1891 | |
| 1892 | /* verify the cpu speed can be set within this limit */ |
| 1893 | ret = cpufreq_driver->verify(new_policy); |
| 1894 | if (ret) |
| 1895 | goto error_out; |
| 1896 | |
| 1897 | /* adjust if necessary - all reasons */ |
| 1898 | blocking_notifier_call_chain(&cpufreq_policy_notifier_list, |
| 1899 | CPUFREQ_ADJUST, new_policy); |
| 1900 | |
| 1901 | /* adjust if necessary - hardware incompatibility*/ |
| 1902 | blocking_notifier_call_chain(&cpufreq_policy_notifier_list, |
| 1903 | CPUFREQ_INCOMPATIBLE, new_policy); |
| 1904 | |
| 1905 | /* |
| 1906 | * verify the cpu speed can be set within this limit, which might be |
| 1907 | * different to the first one |
| 1908 | */ |
| 1909 | ret = cpufreq_driver->verify(new_policy); |
| 1910 | if (ret) |
| 1911 | goto error_out; |
| 1912 | |
| 1913 | /* notification of the new policy */ |
| 1914 | blocking_notifier_call_chain(&cpufreq_policy_notifier_list, |
| 1915 | CPUFREQ_NOTIFY, new_policy); |
| 1916 | |
| 1917 | policy->min = new_policy->min; |
| 1918 | policy->max = new_policy->max; |
| 1919 | |
| 1920 | pr_debug("new min and max freqs are %u - %u kHz\n", |
| 1921 | policy->min, policy->max); |
| 1922 | |
| 1923 | if (cpufreq_driver->setpolicy) { |
| 1924 | policy->policy = new_policy->policy; |
| 1925 | pr_debug("setting range\n"); |
| 1926 | ret = cpufreq_driver->setpolicy(new_policy); |
| 1927 | } else { |
| 1928 | if (new_policy->governor != policy->governor) { |
| 1929 | /* save old, working values */ |
| 1930 | struct cpufreq_governor *old_gov = policy->governor; |
| 1931 | |
| 1932 | pr_debug("governor switch\n"); |
| 1933 | |
| 1934 | /* end old governor */ |
| 1935 | if (policy->governor) { |
| 1936 | __cpufreq_governor(policy, CPUFREQ_GOV_STOP); |
| 1937 | unlock_policy_rwsem_write(new_policy->cpu); |
| 1938 | __cpufreq_governor(policy, |
| 1939 | CPUFREQ_GOV_POLICY_EXIT); |
| 1940 | lock_policy_rwsem_write(new_policy->cpu); |
| 1941 | } |
| 1942 | |
| 1943 | /* start new governor */ |
| 1944 | policy->governor = new_policy->governor; |
| 1945 | if (!__cpufreq_governor(policy, CPUFREQ_GOV_POLICY_INIT)) { |
| 1946 | if (!__cpufreq_governor(policy, CPUFREQ_GOV_START)) { |
| 1947 | failed = 0; |
| 1948 | } else { |
| 1949 | unlock_policy_rwsem_write(new_policy->cpu); |
| 1950 | __cpufreq_governor(policy, |
| 1951 | CPUFREQ_GOV_POLICY_EXIT); |
| 1952 | lock_policy_rwsem_write(new_policy->cpu); |
| 1953 | } |
| 1954 | } |
| 1955 | |
| 1956 | if (failed) { |
| 1957 | /* new governor failed, so re-start old one */ |
| 1958 | pr_debug("starting governor %s failed\n", |
| 1959 | policy->governor->name); |
| 1960 | if (old_gov) { |
| 1961 | policy->governor = old_gov; |
| 1962 | __cpufreq_governor(policy, |
| 1963 | CPUFREQ_GOV_POLICY_INIT); |
| 1964 | __cpufreq_governor(policy, |
| 1965 | CPUFREQ_GOV_START); |
| 1966 | } |
| 1967 | ret = -EINVAL; |
| 1968 | goto error_out; |
| 1969 | } |
| 1970 | /* might be a policy change, too, so fall through */ |
| 1971 | } |
| 1972 | pr_debug("governor: change or update limits\n"); |
| 1973 | ret = __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS); |
| 1974 | } |
| 1975 | |
| 1976 | error_out: |
| 1977 | return ret; |
| 1978 | } |
| 1979 | |
| 1980 | /** |
| 1981 | * cpufreq_update_policy - re-evaluate an existing cpufreq policy |
| 1982 | * @cpu: CPU which shall be re-evaluated |
| 1983 | * |
| 1984 | * Useful for policy notifiers which have different necessities |
| 1985 | * at different times. |
| 1986 | */ |
| 1987 | int cpufreq_update_policy(unsigned int cpu) |
| 1988 | { |
| 1989 | struct cpufreq_policy *policy = cpufreq_cpu_get(cpu); |
| 1990 | struct cpufreq_policy new_policy; |
| 1991 | int ret; |
| 1992 | |
| 1993 | if (!policy) { |
| 1994 | ret = -ENODEV; |
| 1995 | goto no_policy; |
| 1996 | } |
| 1997 | |
| 1998 | if (unlikely(lock_policy_rwsem_write(cpu))) { |
| 1999 | ret = -EINVAL; |
| 2000 | goto fail; |
| 2001 | } |
| 2002 | |
| 2003 | pr_debug("updating policy for CPU %u\n", cpu); |
| 2004 | memcpy(&new_policy, policy, sizeof(*policy)); |
| 2005 | new_policy.min = policy->user_policy.min; |
| 2006 | new_policy.max = policy->user_policy.max; |
| 2007 | new_policy.policy = policy->user_policy.policy; |
| 2008 | new_policy.governor = policy->user_policy.governor; |
| 2009 | |
| 2010 | /* |
| 2011 | * BIOS might change freq behind our back |
| 2012 | * -> ask driver for current freq and notify governors about a change |
| 2013 | */ |
| 2014 | if (cpufreq_driver->get) { |
| 2015 | new_policy.cur = cpufreq_driver->get(cpu); |
| 2016 | if (!policy->cur) { |
| 2017 | pr_debug("Driver did not initialize current freq"); |
| 2018 | policy->cur = new_policy.cur; |
| 2019 | } else { |
| 2020 | if (policy->cur != new_policy.cur && cpufreq_driver->target) |
| 2021 | cpufreq_out_of_sync(cpu, policy->cur, |
| 2022 | new_policy.cur); |
| 2023 | } |
| 2024 | } |
| 2025 | |
| 2026 | ret = __cpufreq_set_policy(policy, &new_policy); |
| 2027 | |
| 2028 | unlock_policy_rwsem_write(cpu); |
| 2029 | |
| 2030 | fail: |
| 2031 | cpufreq_cpu_put(policy); |
| 2032 | no_policy: |
| 2033 | return ret; |
| 2034 | } |
| 2035 | EXPORT_SYMBOL(cpufreq_update_policy); |
| 2036 | |
| 2037 | static int cpufreq_cpu_callback(struct notifier_block *nfb, |
| 2038 | unsigned long action, void *hcpu) |
| 2039 | { |
| 2040 | unsigned int cpu = (unsigned long)hcpu; |
| 2041 | struct device *dev; |
| 2042 | bool frozen = false; |
| 2043 | |
| 2044 | dev = get_cpu_device(cpu); |
| 2045 | if (dev) { |
| 2046 | |
| 2047 | if (action & CPU_TASKS_FROZEN) |
| 2048 | frozen = true; |
| 2049 | |
| 2050 | switch (action & ~CPU_TASKS_FROZEN) { |
| 2051 | case CPU_ONLINE: |
| 2052 | __cpufreq_add_dev(dev, NULL, frozen); |
| 2053 | cpufreq_update_policy(cpu); |
| 2054 | break; |
| 2055 | |
| 2056 | case CPU_DOWN_PREPARE: |
| 2057 | __cpufreq_remove_dev_prepare(dev, NULL, frozen); |
| 2058 | break; |
| 2059 | |
| 2060 | case CPU_POST_DEAD: |
| 2061 | __cpufreq_remove_dev_finish(dev, NULL, frozen); |
| 2062 | break; |
| 2063 | |
| 2064 | case CPU_DOWN_FAILED: |
| 2065 | __cpufreq_add_dev(dev, NULL, frozen); |
| 2066 | break; |
| 2067 | } |
| 2068 | } |
| 2069 | return NOTIFY_OK; |
| 2070 | } |
| 2071 | |
| 2072 | static struct notifier_block __refdata cpufreq_cpu_notifier = { |
| 2073 | .notifier_call = cpufreq_cpu_callback, |
| 2074 | }; |
| 2075 | |
| 2076 | /********************************************************************* |
| 2077 | * REGISTER / UNREGISTER CPUFREQ DRIVER * |
| 2078 | *********************************************************************/ |
| 2079 | |
| 2080 | /** |
| 2081 | * cpufreq_register_driver - register a CPU Frequency driver |
| 2082 | * @driver_data: A struct cpufreq_driver containing the values# |
| 2083 | * submitted by the CPU Frequency driver. |
| 2084 | * |
| 2085 | * Registers a CPU Frequency driver to this core code. This code |
| 2086 | * returns zero on success, -EBUSY when another driver got here first |
| 2087 | * (and isn't unregistered in the meantime). |
| 2088 | * |
| 2089 | */ |
| 2090 | int cpufreq_register_driver(struct cpufreq_driver *driver_data) |
| 2091 | { |
| 2092 | unsigned long flags; |
| 2093 | int ret; |
| 2094 | |
| 2095 | if (cpufreq_disabled()) |
| 2096 | return -ENODEV; |
| 2097 | |
| 2098 | if (!driver_data || !driver_data->verify || !driver_data->init || |
| 2099 | ((!driver_data->setpolicy) && (!driver_data->target))) |
| 2100 | return -EINVAL; |
| 2101 | |
| 2102 | pr_debug("trying to register driver %s\n", driver_data->name); |
| 2103 | |
| 2104 | if (driver_data->setpolicy) |
| 2105 | driver_data->flags |= CPUFREQ_CONST_LOOPS; |
| 2106 | |
| 2107 | write_lock_irqsave(&cpufreq_driver_lock, flags); |
| 2108 | if (cpufreq_driver) { |
| 2109 | write_unlock_irqrestore(&cpufreq_driver_lock, flags); |
| 2110 | return -EEXIST; |
| 2111 | } |
| 2112 | cpufreq_driver = driver_data; |
| 2113 | write_unlock_irqrestore(&cpufreq_driver_lock, flags); |
| 2114 | |
| 2115 | ret = subsys_interface_register(&cpufreq_interface); |
| 2116 | if (ret) |
| 2117 | goto err_null_driver; |
| 2118 | |
| 2119 | if (!(cpufreq_driver->flags & CPUFREQ_STICKY)) { |
| 2120 | int i; |
| 2121 | ret = -ENODEV; |
| 2122 | |
| 2123 | /* check for at least one working CPU */ |
| 2124 | for (i = 0; i < nr_cpu_ids; i++) |
| 2125 | if (cpu_possible(i) && per_cpu(cpufreq_cpu_data, i)) { |
| 2126 | ret = 0; |
| 2127 | break; |
| 2128 | } |
| 2129 | |
| 2130 | /* if all ->init() calls failed, unregister */ |
| 2131 | if (ret) { |
| 2132 | pr_debug("no CPU initialized for driver %s\n", |
| 2133 | driver_data->name); |
| 2134 | goto err_if_unreg; |
| 2135 | } |
| 2136 | } |
| 2137 | |
| 2138 | register_hotcpu_notifier(&cpufreq_cpu_notifier); |
| 2139 | pr_debug("driver %s up and running\n", driver_data->name); |
| 2140 | |
| 2141 | return 0; |
| 2142 | err_if_unreg: |
| 2143 | subsys_interface_unregister(&cpufreq_interface); |
| 2144 | err_null_driver: |
| 2145 | write_lock_irqsave(&cpufreq_driver_lock, flags); |
| 2146 | cpufreq_driver = NULL; |
| 2147 | write_unlock_irqrestore(&cpufreq_driver_lock, flags); |
| 2148 | return ret; |
| 2149 | } |
| 2150 | EXPORT_SYMBOL_GPL(cpufreq_register_driver); |
| 2151 | |
| 2152 | /** |
| 2153 | * cpufreq_unregister_driver - unregister the current CPUFreq driver |
| 2154 | * |
| 2155 | * Unregister the current CPUFreq driver. Only call this if you have |
| 2156 | * the right to do so, i.e. if you have succeeded in initialising before! |
| 2157 | * Returns zero if successful, and -EINVAL if the cpufreq_driver is |
| 2158 | * currently not initialised. |
| 2159 | */ |
| 2160 | int cpufreq_unregister_driver(struct cpufreq_driver *driver) |
| 2161 | { |
| 2162 | unsigned long flags; |
| 2163 | |
| 2164 | if (!cpufreq_driver || (driver != cpufreq_driver)) |
| 2165 | return -EINVAL; |
| 2166 | |
| 2167 | pr_debug("unregistering driver %s\n", driver->name); |
| 2168 | |
| 2169 | subsys_interface_unregister(&cpufreq_interface); |
| 2170 | unregister_hotcpu_notifier(&cpufreq_cpu_notifier); |
| 2171 | |
| 2172 | down_write(&cpufreq_rwsem); |
| 2173 | write_lock_irqsave(&cpufreq_driver_lock, flags); |
| 2174 | |
| 2175 | cpufreq_driver = NULL; |
| 2176 | |
| 2177 | write_unlock_irqrestore(&cpufreq_driver_lock, flags); |
| 2178 | up_write(&cpufreq_rwsem); |
| 2179 | |
| 2180 | return 0; |
| 2181 | } |
| 2182 | EXPORT_SYMBOL_GPL(cpufreq_unregister_driver); |
| 2183 | |
| 2184 | static int __init cpufreq_core_init(void) |
| 2185 | { |
| 2186 | int cpu; |
| 2187 | |
| 2188 | if (cpufreq_disabled()) |
| 2189 | return -ENODEV; |
| 2190 | |
| 2191 | for_each_possible_cpu(cpu) |
| 2192 | init_rwsem(&per_cpu(cpu_policy_rwsem, cpu)); |
| 2193 | |
| 2194 | cpufreq_global_kobject = kobject_create(); |
| 2195 | BUG_ON(!cpufreq_global_kobject); |
| 2196 | register_syscore_ops(&cpufreq_syscore_ops); |
| 2197 | |
| 2198 | return 0; |
| 2199 | } |
| 2200 | core_initcall(cpufreq_core_init); |