2 * linux/drivers/thermal/cpu_cooling.c
4 * Copyright (C) 2012 Samsung Electronics Co., Ltd(http://www.samsung.com)
5 * Copyright (C) 2012 Amit Daniel <amit.kachhap@linaro.org>
7 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; version 2 of the License.
12 * This program is distributed in the hope that it will be useful, but
13 * WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * General Public License for more details.
17 * You should have received a copy of the GNU General Public License along
18 * with this program; if not, write to the Free Software Foundation, Inc.,
19 * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
21 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
23 #include <linux/module.h>
24 #include <linux/thermal.h>
25 #include <linux/cpufreq.h>
26 #include <linux/err.h>
27 #include <linux/slab.h>
28 #include <linux/cpu.h>
29 #include <linux/cpu_cooling.h>
32 * Cooling state <-> CPUFreq frequency
34 * Cooling states are translated to frequencies throughout this driver and this
35 * is the relation between them.
37 * Highest cooling state corresponds to lowest possible frequency.
40 * level 0 --> 1st Max Freq
41 * level 1 --> 2nd Max Freq
46 * struct cpufreq_cooling_device - data for cooling device with cpufreq
47 * @id: unique integer value corresponding to each cpufreq_cooling_device
49 * @cool_dev: thermal_cooling_device pointer to keep track of the
50 * registered cooling device.
51 * @cpufreq_state: integer value representing the current state of cpufreq
53 * @cpufreq_val: integer value representing the absolute value of the clipped
55 * @allowed_cpus: all the cpus involved for this cpufreq_cooling_device.
57 * This structure is required for keeping information of each registered
58 * cpufreq_cooling_device.
60 struct cpufreq_cooling_device {
62 struct thermal_cooling_device *cool_dev;
63 unsigned int cpufreq_state;
64 unsigned int cpufreq_val;
65 struct cpumask allowed_cpus;
66 struct list_head node;
68 static DEFINE_IDR(cpufreq_idr);
69 static DEFINE_MUTEX(cooling_cpufreq_lock);
71 static unsigned int cpufreq_dev_count;
73 static LIST_HEAD(cpufreq_dev_list);
76 * get_idr - function to get a unique id.
77 * @idr: struct idr * handle used to create a id.
78 * @id: int * value generated by this function.
80 * This function will populate @id with an unique
81 * id, using the idr API.
83 * Return: 0 on success, an error code on failure.
85 static int get_idr(struct idr *idr, int *id)
89 mutex_lock(&cooling_cpufreq_lock);
90 ret = idr_alloc(idr, NULL, 0, 0, GFP_KERNEL);
91 mutex_unlock(&cooling_cpufreq_lock);
92 if (unlikely(ret < 0))
100 * release_idr - function to free the unique id.
101 * @idr: struct idr * handle used for creating the id.
102 * @id: int value representing the unique id.
104 static void release_idr(struct idr *idr, int id)
106 mutex_lock(&cooling_cpufreq_lock);
108 mutex_unlock(&cooling_cpufreq_lock);
111 /* Below code defines functions to be used for cpufreq as cooling device */
113 enum cpufreq_cooling_property {
120 * get_property - fetch a property of interest for a given cpu.
121 * @cpu: cpu for which the property is required
122 * @input: query parameter
123 * @output: query return
124 * @property: type of query (frequency, level, max level)
126 * This is the common function to
127 * 1. get maximum cpu cooling states
128 * 2. translate frequency to cooling state
129 * 3. translate cooling state to frequency
131 * Note that the code may be not in good shape
132 * but it is written in this way in order to:
133 * a) reduce duplicate code as most of the code can be shared.
134 * b) make sure the logic is consistent when translating between
135 * cooling states and frequencies.
137 * Return: 0 on success, -EINVAL when invalid parameters are passed.
139 static int get_property(unsigned int cpu, unsigned long input,
140 unsigned int *output,
141 enum cpufreq_cooling_property property)
144 unsigned long max_level = 0, level = 0;
145 unsigned int freq = CPUFREQ_ENTRY_INVALID;
147 struct cpufreq_frequency_table *pos, *table =
148 cpufreq_frequency_get_table(cpu);
156 cpufreq_for_each_valid_entry(pos, table) {
157 /* ignore duplicate entry */
158 if (freq == pos->frequency)
161 /* get the frequency order */
162 if (freq != CPUFREQ_ENTRY_INVALID && descend == -1)
163 descend = freq > pos->frequency;
165 freq = pos->frequency;
169 /* No valid cpu frequency entry */
173 /* max_level is an index, not a counter */
177 if (property == GET_MAXL) {
178 *output = (unsigned int)max_level;
182 if (property == GET_FREQ)
183 level = descend ? input : (max_level - input);
186 cpufreq_for_each_valid_entry(pos, table) {
187 /* ignore duplicate entry */
188 if (freq == pos->frequency)
191 /* now we have a valid frequency entry */
192 freq = pos->frequency;
194 if (property == GET_LEVEL && (unsigned int)input == freq) {
195 /* get level by frequency */
196 *output = descend ? i : (max_level - i);
199 if (property == GET_FREQ && level == i) {
200 /* get frequency by level */
211 * cpufreq_cooling_get_level - for a given cpu, return the cooling level.
212 * @cpu: cpu for which the level is required
213 * @freq: the frequency of interest
215 * This function will match the cooling level corresponding to the
216 * requested @freq and return it.
218 * Return: The matched cooling level on success or THERMAL_CSTATE_INVALID
221 unsigned long cpufreq_cooling_get_level(unsigned int cpu, unsigned int freq)
225 if (get_property(cpu, (unsigned long)freq, &val, GET_LEVEL))
226 return THERMAL_CSTATE_INVALID;
228 return (unsigned long)val;
230 EXPORT_SYMBOL_GPL(cpufreq_cooling_get_level);
233 * get_cpu_frequency - get the absolute value of frequency from level.
234 * @cpu: cpu for which frequency is fetched.
235 * @level: cooling level
237 * This function matches cooling level with frequency. Based on a cooling level
238 * of frequency, equals cooling state of cpu cooling device, it will return
239 * the corresponding frequency.
240 * e.g level=0 --> 1st MAX FREQ, level=1 ---> 2nd MAX FREQ, .... etc
242 * Return: 0 on error, the corresponding frequency otherwise.
244 static unsigned int get_cpu_frequency(unsigned int cpu, unsigned long level)
249 ret = get_property(cpu, level, &freq, GET_FREQ);
257 * cpufreq_thermal_notifier - notifier callback for cpufreq policy change.
258 * @nb: struct notifier_block * with callback info.
259 * @event: value showing cpufreq event for which this function invoked.
260 * @data: callback-specific data
262 * Callback to hijack the notification on cpufreq policy transition.
263 * Every time there is a change in policy, we will intercept and
264 * update the cpufreq policy with thermal constraints.
266 * Return: 0 (success)
268 static int cpufreq_thermal_notifier(struct notifier_block *nb,
269 unsigned long event, void *data)
271 struct cpufreq_policy *policy = data;
272 unsigned long max_freq = 0;
273 struct cpufreq_cooling_device *cpufreq_dev;
275 if (event != CPUFREQ_ADJUST)
278 mutex_lock(&cooling_cpufreq_lock);
279 list_for_each_entry(cpufreq_dev, &cpufreq_dev_list, node) {
280 if (!cpumask_test_cpu(policy->cpu,
281 &cpufreq_dev->allowed_cpus))
284 max_freq = cpufreq_dev->cpufreq_val;
286 if (policy->max != max_freq)
287 cpufreq_verify_within_limits(policy, 0, max_freq);
289 mutex_unlock(&cooling_cpufreq_lock);
294 /* cpufreq cooling device callback functions are defined below */
297 * cpufreq_get_max_state - callback function to get the max cooling state.
298 * @cdev: thermal cooling device pointer.
299 * @state: fill this variable with the max cooling state.
301 * Callback for the thermal cooling device to return the cpufreq
304 * Return: 0 on success, an error code otherwise.
306 static int cpufreq_get_max_state(struct thermal_cooling_device *cdev,
307 unsigned long *state)
309 struct cpufreq_cooling_device *cpufreq_device = cdev->devdata;
310 struct cpumask *mask = &cpufreq_device->allowed_cpus;
312 unsigned int count = 0;
315 cpu = cpumask_any(mask);
317 ret = get_property(cpu, 0, &count, GET_MAXL);
326 * cpufreq_get_cur_state - callback function to get the current cooling state.
327 * @cdev: thermal cooling device pointer.
328 * @state: fill this variable with the current cooling state.
330 * Callback for the thermal cooling device to return the cpufreq
331 * current cooling state.
333 * Return: 0 on success, an error code otherwise.
335 static int cpufreq_get_cur_state(struct thermal_cooling_device *cdev,
336 unsigned long *state)
338 struct cpufreq_cooling_device *cpufreq_device = cdev->devdata;
340 *state = cpufreq_device->cpufreq_state;
346 * cpufreq_set_cur_state - callback function to set the current cooling state.
347 * @cdev: thermal cooling device pointer.
348 * @state: set this variable to the current cooling state.
350 * Callback for the thermal cooling device to change the cpufreq
351 * current cooling state.
353 * Return: 0 on success, an error code otherwise.
355 static int cpufreq_set_cur_state(struct thermal_cooling_device *cdev,
358 struct cpufreq_cooling_device *cpufreq_device = cdev->devdata;
359 unsigned int cpu = cpumask_any(&cpufreq_device->allowed_cpus);
360 unsigned int clip_freq;
362 /* Check if the old cooling action is same as new cooling action */
363 if (cpufreq_device->cpufreq_state == state)
366 clip_freq = get_cpu_frequency(cpu, state);
370 cpufreq_device->cpufreq_state = state;
371 cpufreq_device->cpufreq_val = clip_freq;
373 cpufreq_update_policy(cpu);
378 /* Bind cpufreq callbacks to thermal cooling device ops */
379 static struct thermal_cooling_device_ops const cpufreq_cooling_ops = {
380 .get_max_state = cpufreq_get_max_state,
381 .get_cur_state = cpufreq_get_cur_state,
382 .set_cur_state = cpufreq_set_cur_state,
385 /* Notifier for cpufreq policy change */
386 static struct notifier_block thermal_cpufreq_notifier_block = {
387 .notifier_call = cpufreq_thermal_notifier,
391 * __cpufreq_cooling_register - helper function to create cpufreq cooling device
392 * @np: a valid struct device_node to the cooling device device tree node
393 * @clip_cpus: cpumask of cpus where the frequency constraints will happen.
394 * Normally this should be same as cpufreq policy->related_cpus.
396 * This interface function registers the cpufreq cooling device with the name
397 * "thermal-cpufreq-%x". This api can support multiple instances of cpufreq
398 * cooling devices. It also gives the opportunity to link the cooling device
399 * with a device tree node, in order to bind it via the thermal DT code.
401 * Return: a valid struct thermal_cooling_device pointer on success,
402 * on failure, it returns a corresponding ERR_PTR().
404 static struct thermal_cooling_device *
405 __cpufreq_cooling_register(struct device_node *np,
406 const struct cpumask *clip_cpus)
408 struct thermal_cooling_device *cool_dev;
409 struct cpufreq_cooling_device *cpufreq_dev;
410 char dev_name[THERMAL_NAME_LENGTH];
413 if (!cpufreq_frequency_get_table(cpumask_first(clip_cpus))) {
414 pr_debug("%s: CPUFreq table not found\n", __func__);
415 return ERR_PTR(-EPROBE_DEFER);
418 cpufreq_dev = kzalloc(sizeof(*cpufreq_dev), GFP_KERNEL);
420 return ERR_PTR(-ENOMEM);
422 cpufreq_dev->cpufreq_val = get_cpu_frequency(cpumask_any(clip_cpus), 0);
423 if (!cpufreq_dev->cpufreq_val) {
424 pr_err("%s: Failed to get frequency", __func__);
425 cool_dev = ERR_PTR(-EINVAL);
429 cpumask_copy(&cpufreq_dev->allowed_cpus, clip_cpus);
431 ret = get_idr(&cpufreq_idr, &cpufreq_dev->id);
433 cool_dev = ERR_PTR(ret);
437 snprintf(dev_name, sizeof(dev_name), "thermal-cpufreq-%d",
440 cool_dev = thermal_of_cooling_device_register(np, dev_name, cpufreq_dev,
441 &cpufreq_cooling_ops);
442 if (IS_ERR(cool_dev))
445 cpufreq_dev->cool_dev = cool_dev;
447 mutex_lock(&cooling_cpufreq_lock);
449 /* Register the notifier for first cpufreq cooling device */
450 if (cpufreq_dev_count == 0)
451 cpufreq_register_notifier(&thermal_cpufreq_notifier_block,
452 CPUFREQ_POLICY_NOTIFIER);
454 list_add(&cpufreq_dev->node, &cpufreq_dev_list);
456 mutex_unlock(&cooling_cpufreq_lock);
461 release_idr(&cpufreq_idr, cpufreq_dev->id);
469 * cpufreq_cooling_register - function to create cpufreq cooling device.
470 * @clip_cpus: cpumask of cpus where the frequency constraints will happen.
472 * This interface function registers the cpufreq cooling device with the name
473 * "thermal-cpufreq-%x". This api can support multiple instances of cpufreq
476 * Return: a valid struct thermal_cooling_device pointer on success,
477 * on failure, it returns a corresponding ERR_PTR().
479 struct thermal_cooling_device *
480 cpufreq_cooling_register(const struct cpumask *clip_cpus)
482 return __cpufreq_cooling_register(NULL, clip_cpus);
484 EXPORT_SYMBOL_GPL(cpufreq_cooling_register);
487 * of_cpufreq_cooling_register - function to create cpufreq cooling device.
488 * @np: a valid struct device_node to the cooling device device tree node
489 * @clip_cpus: cpumask of cpus where the frequency constraints will happen.
491 * This interface function registers the cpufreq cooling device with the name
492 * "thermal-cpufreq-%x". This api can support multiple instances of cpufreq
493 * cooling devices. Using this API, the cpufreq cooling device will be
494 * linked to the device tree node provided.
496 * Return: a valid struct thermal_cooling_device pointer on success,
497 * on failure, it returns a corresponding ERR_PTR().
499 struct thermal_cooling_device *
500 of_cpufreq_cooling_register(struct device_node *np,
501 const struct cpumask *clip_cpus)
504 return ERR_PTR(-EINVAL);
506 return __cpufreq_cooling_register(np, clip_cpus);
508 EXPORT_SYMBOL_GPL(of_cpufreq_cooling_register);
511 * cpufreq_cooling_unregister - function to remove cpufreq cooling device.
512 * @cdev: thermal cooling device pointer.
514 * This interface function unregisters the "thermal-cpufreq-%x" cooling device.
516 void cpufreq_cooling_unregister(struct thermal_cooling_device *cdev)
518 struct cpufreq_cooling_device *cpufreq_dev;
523 cpufreq_dev = cdev->devdata;
524 mutex_lock(&cooling_cpufreq_lock);
525 list_del(&cpufreq_dev->node);
528 /* Unregister the notifier for the last cpufreq cooling device */
529 if (cpufreq_dev_count == 0)
530 cpufreq_unregister_notifier(&thermal_cpufreq_notifier_block,
531 CPUFREQ_POLICY_NOTIFIER);
532 mutex_unlock(&cooling_cpufreq_lock);
534 thermal_cooling_device_unregister(cpufreq_dev->cool_dev);
535 release_idr(&cpufreq_idr, cpufreq_dev->id);
538 EXPORT_SYMBOL_GPL(cpufreq_cooling_unregister);