1/* 2 * linux/drivers/thermal/cpu_cooling.c 3 * 4 * Copyright (C) 2012 Samsung Electronics Co., Ltd(http://www.samsung.com) 5 * Copyright (C) 2012 Amit Daniel <amit.kachhap@linaro.org> 6 * 7 * Copyright (C) 2014 Viresh Kumar <viresh.kumar@linaro.org> 8 * 9 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 10 * This program is free software; you can redistribute it and/or modify 11 * it under the terms of the GNU General Public License as published by 12 * the Free Software Foundation; version 2 of the License. 13 * 14 * This program is distributed in the hope that it will be useful, but 15 * WITHOUT ANY WARRANTY; without even the implied warranty of 16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 17 * General Public License for more details. 18 * 19 * You should have received a copy of the GNU General Public License along 20 * with this program; if not, write to the Free Software Foundation, Inc., 21 * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA. 22 * 23 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 24 */ 25#include <linux/module.h> 26#include <linux/thermal.h> 27#include <linux/cpufreq.h> 28#include <linux/err.h> 29#include <linux/slab.h> 30#include <linux/cpu.h> 31#include <linux/cpu_cooling.h> 32 33/* 34 * Cooling state <-> CPUFreq frequency 35 * 36 * Cooling states are translated to frequencies throughout this driver and this 37 * is the relation between them. 38 * 39 * Highest cooling state corresponds to lowest possible frequency. 40 * 41 * i.e. 42 * level 0 --> 1st Max Freq 43 * level 1 --> 2nd Max Freq 44 * ... 45 */ 46 47/** 48 * struct cpufreq_cooling_device - data for cooling device with cpufreq 49 * @id: unique integer value corresponding to each cpufreq_cooling_device 50 * registered. 51 * @cool_dev: thermal_cooling_device pointer to keep track of the 52 * registered cooling device. 53 * @cpufreq_state: integer value representing the current state of cpufreq 54 * cooling devices. 55 * @clipped_freq: integer value representing the absolute value of the clipped 56 * frequency. 57 * @max_level: maximum cooling level. One less than total number of valid 58 * cpufreq frequencies. 59 * @allowed_cpus: all the cpus involved for this cpufreq_cooling_device. 60 * @node: list_head to link all cpufreq_cooling_device together. 61 * 62 * This structure is required for keeping information of each registered 63 * cpufreq_cooling_device. 64 */ 65struct cpufreq_cooling_device { 66 int id; 67 struct thermal_cooling_device *cool_dev; 68 unsigned int cpufreq_state; 69 unsigned int clipped_freq; 70 unsigned int max_level; 71 unsigned int *freq_table; /* In descending order */ 72 struct cpumask allowed_cpus; 73 struct list_head node; 74}; 75static DEFINE_IDR(cpufreq_idr); 76static DEFINE_MUTEX(cooling_cpufreq_lock); 77 78static LIST_HEAD(cpufreq_dev_list); 79 80/** 81 * get_idr - function to get a unique id. 82 * @idr: struct idr * handle used to create a id. 83 * @id: int * value generated by this function. 84 * 85 * This function will populate @id with an unique 86 * id, using the idr API. 87 * 88 * Return: 0 on success, an error code on failure. 89 */ 90static int get_idr(struct idr *idr, int *id) 91{ 92 int ret; 93 94 mutex_lock(&cooling_cpufreq_lock); 95 ret = idr_alloc(idr, NULL, 0, 0, GFP_KERNEL); 96 mutex_unlock(&cooling_cpufreq_lock); 97 if (unlikely(ret < 0)) 98 return ret; 99 *id = ret; 100 101 return 0; 102} 103 104/** 105 * release_idr - function to free the unique id. 106 * @idr: struct idr * handle used for creating the id. 107 * @id: int value representing the unique id. 108 */ 109static void release_idr(struct idr *idr, int id) 110{ 111 mutex_lock(&cooling_cpufreq_lock); 112 idr_remove(idr, id); 113 mutex_unlock(&cooling_cpufreq_lock); 114} 115 116/* Below code defines functions to be used for cpufreq as cooling device */ 117 118/** 119 * get_level: Find the level for a particular frequency 120 * @cpufreq_dev: cpufreq_dev for which the property is required 121 * @freq: Frequency 122 * 123 * Return: level on success, THERMAL_CSTATE_INVALID on error. 124 */ 125static unsigned long get_level(struct cpufreq_cooling_device *cpufreq_dev, 126 unsigned int freq) 127{ 128 unsigned long level; 129 130 for (level = 0; level <= cpufreq_dev->max_level; level++) { 131 if (freq == cpufreq_dev->freq_table[level]) 132 return level; 133 134 if (freq > cpufreq_dev->freq_table[level]) 135 break; 136 } 137 138 return THERMAL_CSTATE_INVALID; 139} 140 141/** 142 * cpufreq_cooling_get_level - for a given cpu, return the cooling level. 143 * @cpu: cpu for which the level is required 144 * @freq: the frequency of interest 145 * 146 * This function will match the cooling level corresponding to the 147 * requested @freq and return it. 148 * 149 * Return: The matched cooling level on success or THERMAL_CSTATE_INVALID 150 * otherwise. 151 */ 152unsigned long cpufreq_cooling_get_level(unsigned int cpu, unsigned int freq) 153{ 154 struct cpufreq_cooling_device *cpufreq_dev; 155 156 mutex_lock(&cooling_cpufreq_lock); 157 list_for_each_entry(cpufreq_dev, &cpufreq_dev_list, node) { 158 if (cpumask_test_cpu(cpu, &cpufreq_dev->allowed_cpus)) { 159 mutex_unlock(&cooling_cpufreq_lock); 160 return get_level(cpufreq_dev, freq); 161 } 162 } 163 mutex_unlock(&cooling_cpufreq_lock); 164 165 pr_err("%s: cpu:%d not part of any cooling device\n", __func__, cpu); 166 return THERMAL_CSTATE_INVALID; 167} 168EXPORT_SYMBOL_GPL(cpufreq_cooling_get_level); 169 170/** 171 * cpufreq_thermal_notifier - notifier callback for cpufreq policy change. 172 * @nb: struct notifier_block * with callback info. 173 * @event: value showing cpufreq event for which this function invoked. 174 * @data: callback-specific data 175 * 176 * Callback to hijack the notification on cpufreq policy transition. 177 * Every time there is a change in policy, we will intercept and 178 * update the cpufreq policy with thermal constraints. 179 * 180 * Return: 0 (success) 181 */ 182static int cpufreq_thermal_notifier(struct notifier_block *nb, 183 unsigned long event, void *data) 184{ 185 struct cpufreq_policy *policy = data; 186 unsigned long max_freq = 0; 187 struct cpufreq_cooling_device *cpufreq_dev; 188 189 if (event != CPUFREQ_ADJUST) 190 return 0; 191 192 mutex_lock(&cooling_cpufreq_lock); 193 list_for_each_entry(cpufreq_dev, &cpufreq_dev_list, node) { 194 if (!cpumask_test_cpu(policy->cpu, 195 &cpufreq_dev->allowed_cpus)) 196 continue; 197 198 max_freq = cpufreq_dev->clipped_freq; 199 200 if (policy->max != max_freq) 201 cpufreq_verify_within_limits(policy, 0, max_freq); 202 } 203 mutex_unlock(&cooling_cpufreq_lock); 204 205 return 0; 206} 207 208/* cpufreq cooling device callback functions are defined below */ 209 210/** 211 * cpufreq_get_max_state - callback function to get the max cooling state. 212 * @cdev: thermal cooling device pointer. 213 * @state: fill this variable with the max cooling state. 214 * 215 * Callback for the thermal cooling device to return the cpufreq 216 * max cooling state. 217 * 218 * Return: 0 on success, an error code otherwise. 219 */ 220static int cpufreq_get_max_state(struct thermal_cooling_device *cdev, 221 unsigned long *state) 222{ 223 struct cpufreq_cooling_device *cpufreq_device = cdev->devdata; 224 225 *state = cpufreq_device->max_level; 226 return 0; 227} 228 229/** 230 * cpufreq_get_cur_state - callback function to get the current cooling state. 231 * @cdev: thermal cooling device pointer. 232 * @state: fill this variable with the current cooling state. 233 * 234 * Callback for the thermal cooling device to return the cpufreq 235 * current cooling state. 236 * 237 * Return: 0 on success, an error code otherwise. 238 */ 239static int cpufreq_get_cur_state(struct thermal_cooling_device *cdev, 240 unsigned long *state) 241{ 242 struct cpufreq_cooling_device *cpufreq_device = cdev->devdata; 243 244 *state = cpufreq_device->cpufreq_state; 245 246 return 0; 247} 248 249/** 250 * cpufreq_set_cur_state - callback function to set the current cooling state. 251 * @cdev: thermal cooling device pointer. 252 * @state: set this variable to the current cooling state. 253 * 254 * Callback for the thermal cooling device to change the cpufreq 255 * current cooling state. 256 * 257 * Return: 0 on success, an error code otherwise. 258 */ 259static int cpufreq_set_cur_state(struct thermal_cooling_device *cdev, 260 unsigned long state) 261{ 262 struct cpufreq_cooling_device *cpufreq_device = cdev->devdata; 263 unsigned int cpu = cpumask_any(&cpufreq_device->allowed_cpus); 264 unsigned int clip_freq; 265 266 /* Request state should be less than max_level */ 267 if (WARN_ON(state > cpufreq_device->max_level)) 268 return -EINVAL; 269 270 /* Check if the old cooling action is same as new cooling action */ 271 if (cpufreq_device->cpufreq_state == state) 272 return 0; 273 274 clip_freq = cpufreq_device->freq_table[state]; 275 cpufreq_device->cpufreq_state = state; 276 cpufreq_device->clipped_freq = clip_freq; 277 278 cpufreq_update_policy(cpu); 279 280 return 0; 281} 282 283/* Bind cpufreq callbacks to thermal cooling device ops */ 284static struct thermal_cooling_device_ops const cpufreq_cooling_ops = { 285 .get_max_state = cpufreq_get_max_state, 286 .get_cur_state = cpufreq_get_cur_state, 287 .set_cur_state = cpufreq_set_cur_state, 288}; 289 290/* Notifier for cpufreq policy change */ 291static struct notifier_block thermal_cpufreq_notifier_block = { 292 .notifier_call = cpufreq_thermal_notifier, 293}; 294 295static unsigned int find_next_max(struct cpufreq_frequency_table *table, 296 unsigned int prev_max) 297{ 298 struct cpufreq_frequency_table *pos; 299 unsigned int max = 0; 300 301 cpufreq_for_each_valid_entry(pos, table) { 302 if (pos->frequency > max && pos->frequency < prev_max) 303 max = pos->frequency; 304 } 305 306 return max; 307} 308 309/** 310 * __cpufreq_cooling_register - helper function to create cpufreq cooling device 311 * @np: a valid struct device_node to the cooling device device tree node 312 * @clip_cpus: cpumask of cpus where the frequency constraints will happen. 313 * Normally this should be same as cpufreq policy->related_cpus. 314 * 315 * This interface function registers the cpufreq cooling device with the name 316 * "thermal-cpufreq-%x". This api can support multiple instances of cpufreq 317 * cooling devices. It also gives the opportunity to link the cooling device 318 * with a device tree node, in order to bind it via the thermal DT code. 319 * 320 * Return: a valid struct thermal_cooling_device pointer on success, 321 * on failure, it returns a corresponding ERR_PTR(). 322 */ 323static struct thermal_cooling_device * 324__cpufreq_cooling_register(struct device_node *np, 325 const struct cpumask *clip_cpus) 326{ 327 struct thermal_cooling_device *cool_dev; 328 struct cpufreq_cooling_device *cpufreq_dev; 329 char dev_name[THERMAL_NAME_LENGTH]; 330 struct cpufreq_frequency_table *pos, *table; 331 unsigned int freq, i; 332 int ret; 333 334 table = cpufreq_frequency_get_table(cpumask_first(clip_cpus)); 335 if (!table) { 336 pr_debug("%s: CPUFreq table not found\n", __func__); 337 return ERR_PTR(-EPROBE_DEFER); 338 } 339 340 cpufreq_dev = kzalloc(sizeof(*cpufreq_dev), GFP_KERNEL); 341 if (!cpufreq_dev) 342 return ERR_PTR(-ENOMEM); 343 344 /* Find max levels */ 345 cpufreq_for_each_valid_entry(pos, table) 346 cpufreq_dev->max_level++; 347 348 cpufreq_dev->freq_table = kmalloc(sizeof(*cpufreq_dev->freq_table) * 349 cpufreq_dev->max_level, GFP_KERNEL); 350 if (!cpufreq_dev->freq_table) { 351 cool_dev = ERR_PTR(-ENOMEM); 352 goto free_cdev; 353 } 354 355 /* max_level is an index, not a counter */ 356 cpufreq_dev->max_level--; 357 358 cpumask_copy(&cpufreq_dev->allowed_cpus, clip_cpus); 359 360 ret = get_idr(&cpufreq_idr, &cpufreq_dev->id); 361 if (ret) { 362 cool_dev = ERR_PTR(ret); 363 goto free_table; 364 } 365 366 /* Fill freq-table in descending order of frequencies */ 367 for (i = 0, freq = -1; i <= cpufreq_dev->max_level; i++) { 368 freq = find_next_max(table, freq); 369 cpufreq_dev->freq_table[i] = freq; 370 371 /* Warn for duplicate entries */ 372 if (!freq) 373 pr_warn("%s: table has duplicate entries\n", __func__); 374 else 375 pr_debug("%s: freq:%u KHz\n", __func__, freq); 376 } 377 378 snprintf(dev_name, sizeof(dev_name), "thermal-cpufreq-%d", 379 cpufreq_dev->id); 380 381 cool_dev = thermal_of_cooling_device_register(np, dev_name, cpufreq_dev, 382 &cpufreq_cooling_ops); 383 if (IS_ERR(cool_dev)) 384 goto remove_idr; 385 386 cpufreq_dev->clipped_freq = cpufreq_dev->freq_table[0]; 387 cpufreq_dev->cool_dev = cool_dev; 388 389 mutex_lock(&cooling_cpufreq_lock); 390 391 /* Register the notifier for first cpufreq cooling device */ 392 if (list_empty(&cpufreq_dev_list)) 393 cpufreq_register_notifier(&thermal_cpufreq_notifier_block, 394 CPUFREQ_POLICY_NOTIFIER); 395 list_add(&cpufreq_dev->node, &cpufreq_dev_list); 396 397 mutex_unlock(&cooling_cpufreq_lock); 398 399 return cool_dev; 400 401remove_idr: 402 release_idr(&cpufreq_idr, cpufreq_dev->id); 403free_table: 404 kfree(cpufreq_dev->freq_table); 405free_cdev: 406 kfree(cpufreq_dev); 407 408 return cool_dev; 409} 410 411/** 412 * cpufreq_cooling_register - function to create cpufreq cooling device. 413 * @clip_cpus: cpumask of cpus where the frequency constraints will happen. 414 * 415 * This interface function registers the cpufreq cooling device with the name 416 * "thermal-cpufreq-%x". This api can support multiple instances of cpufreq 417 * cooling devices. 418 * 419 * Return: a valid struct thermal_cooling_device pointer on success, 420 * on failure, it returns a corresponding ERR_PTR(). 421 */ 422struct thermal_cooling_device * 423cpufreq_cooling_register(const struct cpumask *clip_cpus) 424{ 425 return __cpufreq_cooling_register(NULL, clip_cpus); 426} 427EXPORT_SYMBOL_GPL(cpufreq_cooling_register); 428 429/** 430 * of_cpufreq_cooling_register - function to create cpufreq cooling device. 431 * @np: a valid struct device_node to the cooling device device tree node 432 * @clip_cpus: cpumask of cpus where the frequency constraints will happen. 433 * 434 * This interface function registers the cpufreq cooling device with the name 435 * "thermal-cpufreq-%x". This api can support multiple instances of cpufreq 436 * cooling devices. Using this API, the cpufreq cooling device will be 437 * linked to the device tree node provided. 438 * 439 * Return: a valid struct thermal_cooling_device pointer on success, 440 * on failure, it returns a corresponding ERR_PTR(). 441 */ 442struct thermal_cooling_device * 443of_cpufreq_cooling_register(struct device_node *np, 444 const struct cpumask *clip_cpus) 445{ 446 if (!np) 447 return ERR_PTR(-EINVAL); 448 449 return __cpufreq_cooling_register(np, clip_cpus); 450} 451EXPORT_SYMBOL_GPL(of_cpufreq_cooling_register); 452 453/** 454 * cpufreq_cooling_unregister - function to remove cpufreq cooling device. 455 * @cdev: thermal cooling device pointer. 456 * 457 * This interface function unregisters the "thermal-cpufreq-%x" cooling device. 458 */ 459void cpufreq_cooling_unregister(struct thermal_cooling_device *cdev) 460{ 461 struct cpufreq_cooling_device *cpufreq_dev; 462 463 if (!cdev) 464 return; 465 466 cpufreq_dev = cdev->devdata; 467 mutex_lock(&cooling_cpufreq_lock); 468 list_del(&cpufreq_dev->node); 469 470 /* Unregister the notifier for the last cpufreq cooling device */ 471 if (list_empty(&cpufreq_dev_list)) 472 cpufreq_unregister_notifier(&thermal_cpufreq_notifier_block, 473 CPUFREQ_POLICY_NOTIFIER); 474 mutex_unlock(&cooling_cpufreq_lock); 475 476 thermal_cooling_device_unregister(cpufreq_dev->cool_dev); 477 release_idr(&cpufreq_idr, cpufreq_dev->id); 478 kfree(cpufreq_dev->freq_table); 479 kfree(cpufreq_dev); 480} 481EXPORT_SYMBOL_GPL(cpufreq_cooling_unregister); 482