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 * struct cpufreq_cooling_device - data for cooling device with cpufreq
33 * @id: unique integer value corresponding to each cpufreq_cooling_device
35 * @cool_dev: thermal_cooling_device pointer to keep track of the
36 * registered cooling device.
37 * @cpufreq_state: integer value representing the current state of cpufreq
39 * @cpufreq_val: integer value representing the absolute value of the clipped
41 * @allowed_cpus: all the cpus involved for this cpufreq_cooling_device.
42 * @node: list_head to link all cpufreq_cooling_device together.
44 * This structure is required for keeping information of each
45 * cpufreq_cooling_device registered as a list whose head is represented by
46 * cooling_cpufreq_list. In order to prevent corruption of this list a
47 * mutex lock cooling_cpufreq_lock is used.
49 struct cpufreq_cooling_device {
51 struct thermal_cooling_device *cool_dev;
52 unsigned int cpufreq_state;
53 unsigned int cpufreq_val;
54 struct cpumask allowed_cpus;
55 struct list_head node;
57 static LIST_HEAD(cooling_cpufreq_list);
58 static DEFINE_IDR(cpufreq_idr);
59 static DEFINE_MUTEX(cooling_cpufreq_lock);
61 static unsigned int cpufreq_dev_count;
63 /* notify_table passes value to the CPUFREQ_ADJUST callback function. */
64 #define NOTIFY_INVALID NULL
65 static struct cpufreq_cooling_device *notify_device;
68 * get_idr - function to get a unique id.
69 * @idr: struct idr * handle used to create a id.
70 * @id: int * value generated by this function.
72 static int get_idr(struct idr *idr, int *id)
76 mutex_lock(&cooling_cpufreq_lock);
77 ret = idr_alloc(idr, NULL, 0, 0, GFP_KERNEL);
78 mutex_unlock(&cooling_cpufreq_lock);
79 if (unlikely(ret < 0))
86 * release_idr - function to free the unique id.
87 * @idr: struct idr * handle used for creating the id.
88 * @id: int value representing the unique id.
90 static void release_idr(struct idr *idr, int id)
92 mutex_lock(&cooling_cpufreq_lock);
94 mutex_unlock(&cooling_cpufreq_lock);
97 /* Below code defines functions to be used for cpufreq as cooling device */
100 * is_cpufreq_valid - function to check frequency transitioning capability.
101 * @cpu: cpu for which check is needed.
103 * This function will check the current state of the system if
104 * it is capable of changing the frequency for a given @cpu.
106 * Return: 0 if the system is not currently capable of changing
107 * the frequency of given cpu. !0 in case the frequency is changeable.
109 static int is_cpufreq_valid(int cpu)
111 struct cpufreq_policy policy;
112 return !cpufreq_get_policy(&policy, cpu);
115 enum cpufreq_cooling_property {
122 * get_property - fetch a property of interest for a give cpu.
123 * @cpu: cpu for which the property is required
124 * @input: query parameter
125 * @output: query return
126 * @property: type of query (frequency, level, max level)
128 * This is the common function to
129 * 1. get maximum cpu cooling states
130 * 2. translate frequency to cooling state
131 * 3. translate cooling state to frequency
132 * Note that the code may be not in good shape
133 * but it is written in this way in order to:
134 * a) reduce duplicate code as most of the code can be shared.
135 * b) make sure the logic is consistent when translating between
136 * cooling states and frequencies.
138 * Return: 0 on success, -EINVAL when invalid parameters are passed.
140 static int get_property(unsigned int cpu, unsigned long input,
141 unsigned int* output, 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 *table =
148 cpufreq_frequency_get_table(cpu);
157 for (i = 0; table[i].frequency != CPUFREQ_TABLE_END; i++) {
158 /* ignore invalid entries */
159 if (table[i].frequency == CPUFREQ_ENTRY_INVALID)
162 /* ignore duplicate entry */
163 if (freq == table[i].frequency)
166 /* get the frequency order */
167 if (freq != CPUFREQ_ENTRY_INVALID && descend != -1)
168 descend = !!(freq > table[i].frequency);
170 freq = table[i].frequency;
175 if (property == GET_MAXL) {
176 *output = (unsigned int)max_level;
180 if (property == GET_FREQ)
181 level = descend ? input : (max_level - input -1);
184 for (i = 0, j = 0; table[i].frequency != CPUFREQ_TABLE_END; i++) {
185 /* ignore invalid entry */
186 if (table[i].frequency == CPUFREQ_ENTRY_INVALID)
189 /* ignore duplicate entry */
190 if (freq == table[i].frequency)
193 /* now we have a valid frequency entry */
194 freq = table[i].frequency;
196 if (property == GET_LEVEL && (unsigned int)input == freq) {
197 /* get level by frequency */
198 *output = descend ? j : (max_level - j - 1);
201 if (property == GET_FREQ && level == j) {
202 /* get frequency by level */
212 * cpufreq_cooling_get_level - for a give cpu, return the cooling level.
213 * @cpu: cpu for which the level is required
214 * @freq: the frequency of interest
216 * This function will match the cooling level corresponding to the
217 * requested @freq and return it.
219 * Return: The matched cooling level on success or THERMAL_CSTATE_INVALID
222 unsigned long cpufreq_cooling_get_level(unsigned int cpu, unsigned int freq)
226 if (get_property(cpu, (unsigned long)freq, &val, GET_LEVEL))
227 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);
256 * cpufreq_apply_cooling - function to apply frequency clipping.
257 * @cpufreq_device: cpufreq_cooling_device pointer containing frequency
259 * @cooling_state: value of the cooling state.
261 static int cpufreq_apply_cooling(struct cpufreq_cooling_device *cpufreq_device,
262 unsigned long cooling_state)
264 unsigned int cpuid, clip_freq;
265 struct cpumask *mask = &cpufreq_device->allowed_cpus;
266 unsigned int cpu = cpumask_any(mask);
269 /* Check if the old cooling action is same as new cooling action */
270 if (cpufreq_device->cpufreq_state == cooling_state)
273 clip_freq = get_cpu_frequency(cpu, cooling_state);
277 cpufreq_device->cpufreq_state = cooling_state;
278 cpufreq_device->cpufreq_val = clip_freq;
279 notify_device = cpufreq_device;
281 for_each_cpu(cpuid, mask) {
282 if (is_cpufreq_valid(cpuid))
283 cpufreq_update_policy(cpuid);
286 notify_device = NOTIFY_INVALID;
292 * cpufreq_thermal_notifier - notifier callback for cpufreq policy change.
293 * @nb: struct notifier_block * with callback info.
294 * @event: value showing cpufreq event for which this function invoked.
295 * @data: callback-specific data
297 static int cpufreq_thermal_notifier(struct notifier_block *nb,
298 unsigned long event, void *data)
300 struct cpufreq_policy *policy = data;
301 unsigned long max_freq = 0;
303 if (event != CPUFREQ_ADJUST || notify_device == NOTIFY_INVALID)
306 if (cpumask_test_cpu(policy->cpu, ¬ify_device->allowed_cpus))
307 max_freq = notify_device->cpufreq_val;
309 /* Never exceed user_policy.max*/
310 if (max_freq > policy->user_policy.max)
311 max_freq = policy->user_policy.max;
313 if (policy->max != max_freq)
314 cpufreq_verify_within_limits(policy, 0, max_freq);
320 * cpufreq cooling device callback functions are defined below
324 * cpufreq_get_max_state - callback function to get the max cooling state.
325 * @cdev: thermal cooling device pointer.
326 * @state: fill this variable with the max cooling state.
328 static int cpufreq_get_max_state(struct thermal_cooling_device *cdev,
329 unsigned long *state)
331 struct cpufreq_cooling_device *cpufreq_device = cdev->devdata;
332 struct cpumask *mask = &cpufreq_device->allowed_cpus;
334 unsigned int count = 0;
337 cpu = cpumask_any(mask);
339 ret = get_property(cpu, 0, &count, GET_MAXL);
348 * cpufreq_get_cur_state - callback function to get the current cooling state.
349 * @cdev: thermal cooling device pointer.
350 * @state: fill this variable with the current cooling state.
352 static int cpufreq_get_cur_state(struct thermal_cooling_device *cdev,
353 unsigned long *state)
355 struct cpufreq_cooling_device *cpufreq_device = cdev->devdata;
357 *state = cpufreq_device->cpufreq_state;
362 * cpufreq_set_cur_state - callback function to set the current cooling state.
363 * @cdev: thermal cooling device pointer.
364 * @state: set this variable to the current cooling state.
366 static int cpufreq_set_cur_state(struct thermal_cooling_device *cdev,
369 struct cpufreq_cooling_device *cpufreq_device = cdev->devdata;
371 return cpufreq_apply_cooling(cpufreq_device, state);
374 /* Bind cpufreq callbacks to thermal cooling device ops */
375 static struct thermal_cooling_device_ops const cpufreq_cooling_ops = {
376 .get_max_state = cpufreq_get_max_state,
377 .get_cur_state = cpufreq_get_cur_state,
378 .set_cur_state = cpufreq_set_cur_state,
381 /* Notifier for cpufreq policy change */
382 static struct notifier_block thermal_cpufreq_notifier_block = {
383 .notifier_call = cpufreq_thermal_notifier,
387 * cpufreq_cooling_register - function to create cpufreq cooling device.
388 * @clip_cpus: cpumask of cpus where the frequency constraints will happen.
390 struct thermal_cooling_device *cpufreq_cooling_register(
391 const struct cpumask *clip_cpus)
393 struct thermal_cooling_device *cool_dev;
394 struct cpufreq_cooling_device *cpufreq_dev = NULL;
395 unsigned int min = 0, max = 0;
396 char dev_name[THERMAL_NAME_LENGTH];
398 struct cpufreq_policy policy;
400 /*Verify that all the clip cpus have same freq_min, freq_max limit*/
401 for_each_cpu(i, clip_cpus) {
402 /*continue if cpufreq policy not found and not return error*/
403 if (!cpufreq_get_policy(&policy, i))
405 if (min == 0 && max == 0) {
406 min = policy.cpuinfo.min_freq;
407 max = policy.cpuinfo.max_freq;
409 if (min != policy.cpuinfo.min_freq ||
410 max != policy.cpuinfo.max_freq)
411 return ERR_PTR(-EINVAL);
414 cpufreq_dev = kzalloc(sizeof(struct cpufreq_cooling_device),
417 return ERR_PTR(-ENOMEM);
419 cpumask_copy(&cpufreq_dev->allowed_cpus, clip_cpus);
421 ret = get_idr(&cpufreq_idr, &cpufreq_dev->id);
424 return ERR_PTR(-EINVAL);
427 sprintf(dev_name, "thermal-cpufreq-%d", cpufreq_dev->id);
429 cool_dev = thermal_cooling_device_register(dev_name, cpufreq_dev,
430 &cpufreq_cooling_ops);
432 release_idr(&cpufreq_idr, cpufreq_dev->id);
434 return ERR_PTR(-EINVAL);
436 cpufreq_dev->cool_dev = cool_dev;
437 cpufreq_dev->cpufreq_state = 0;
438 mutex_lock(&cooling_cpufreq_lock);
440 /* Register the notifier for first cpufreq cooling device */
441 if (cpufreq_dev_count == 0)
442 cpufreq_register_notifier(&thermal_cpufreq_notifier_block,
443 CPUFREQ_POLICY_NOTIFIER);
446 mutex_unlock(&cooling_cpufreq_lock);
449 EXPORT_SYMBOL_GPL(cpufreq_cooling_register);
452 * cpufreq_cooling_unregister - function to remove cpufreq cooling device.
453 * @cdev: thermal cooling device pointer.
455 void cpufreq_cooling_unregister(struct thermal_cooling_device *cdev)
457 struct cpufreq_cooling_device *cpufreq_dev = cdev->devdata;
459 mutex_lock(&cooling_cpufreq_lock);
462 /* Unregister the notifier for the last cpufreq cooling device */
463 if (cpufreq_dev_count == 0) {
464 cpufreq_unregister_notifier(&thermal_cpufreq_notifier_block,
465 CPUFREQ_POLICY_NOTIFIER);
467 mutex_unlock(&cooling_cpufreq_lock);
469 thermal_cooling_device_unregister(cpufreq_dev->cool_dev);
470 release_idr(&cpufreq_idr, cpufreq_dev->id);
473 EXPORT_SYMBOL_GPL(cpufreq_cooling_unregister);