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/kernel.h>
24 #include <linux/module.h>
25 #include <linux/thermal.h>
26 #include <linux/platform_device.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>
34 * struct cpufreq_cooling_device
35 * @id: unique integer value corresponding to each cpufreq_cooling_device
37 * @cool_dev: thermal_cooling_device pointer to keep track of the the
38 * egistered cooling device.
39 * @cpufreq_state: integer value representing the current state of cpufreq
41 * @cpufreq_val: integer value representing the absolute value of the clipped
43 * @allowed_cpus: all the cpus involved for this cpufreq_cooling_device.
44 * @node: list_head to link all cpufreq_cooling_device together.
46 * This structure is required for keeping information of each
47 * cpufreq_cooling_device registered as a list whose head is represented by
48 * cooling_cpufreq_list. In order to prevent corruption of this list a
49 * mutex lock cooling_cpufreq_lock is used.
51 struct cpufreq_cooling_device {
53 struct thermal_cooling_device *cool_dev;
54 unsigned int cpufreq_state;
55 unsigned int cpufreq_val;
56 struct cpumask allowed_cpus;
57 struct list_head node;
59 static LIST_HEAD(cooling_cpufreq_list);
60 static DEFINE_IDR(cpufreq_idr);
61 static DEFINE_MUTEX(cooling_cpufreq_lock);
63 static unsigned int cpufreq_dev_count;
65 /* notify_table passes value to the CPUFREQ_ADJUST callback function. */
66 #define NOTIFY_INVALID NULL
67 static struct cpufreq_cooling_device *notify_device;
70 * get_idr - function to get a unique id.
71 * @idr: struct idr * handle used to create a id.
72 * @id: int * value generated by this function.
74 static int get_idr(struct idr *idr, int *id)
78 mutex_lock(&cooling_cpufreq_lock);
79 ret = idr_alloc(idr, NULL, 0, 0, GFP_KERNEL);
80 mutex_unlock(&cooling_cpufreq_lock);
81 if (unlikely(ret < 0))
88 * release_idr - function to free the unique id.
89 * @idr: struct idr * handle used for creating the id.
90 * @id: int value representing the unique id.
92 static void release_idr(struct idr *idr, int id)
94 mutex_lock(&cooling_cpufreq_lock);
96 mutex_unlock(&cooling_cpufreq_lock);
99 /* Below code defines functions to be used for cpufreq as cooling device */
102 * is_cpufreq_valid - function to check if a cpu has frequency transition policy.
103 * @cpu: cpu for which check is needed.
105 static int is_cpufreq_valid(int cpu)
107 struct cpufreq_policy policy;
108 return !cpufreq_get_policy(&policy, cpu);
112 * get_cpu_frequency - get the absolute value of frequency from level.
113 * @cpu: cpu for which frequency is fetched.
114 * @level: level of frequency, equals cooling state of cpu cooling device
115 * e.g level=0 --> 1st MAX FREQ, level=1 ---> 2nd MAX FREQ, .... etc
117 static unsigned int get_cpu_frequency(unsigned int cpu, unsigned long level)
120 unsigned long level_index;
121 bool descend = false;
122 struct cpufreq_frequency_table *table =
123 cpufreq_frequency_get_table(cpu);
127 while (table[i].frequency != CPUFREQ_TABLE_END) {
128 if (table[i].frequency == CPUFREQ_ENTRY_INVALID)
131 /*check if table in ascending or descending order*/
132 if ((table[i + 1].frequency != CPUFREQ_TABLE_END) &&
133 (table[i + 1].frequency < table[i].frequency)
138 /*return if level matched and table in descending order*/
139 if (descend && i == level)
140 return table[i].frequency;
145 if (level > i || descend)
147 level_index = i - level;
149 /*Scan the table in reverse order and match the level*/
151 if (table[i].frequency == CPUFREQ_ENTRY_INVALID)
153 /*return if level matched*/
154 if (i == level_index)
155 return table[i].frequency;
162 * cpufreq_apply_cooling - function to apply frequency clipping.
163 * @cpufreq_device: cpufreq_cooling_device pointer containing frequency
165 * @cooling_state: value of the cooling state.
167 static int cpufreq_apply_cooling(struct cpufreq_cooling_device *cpufreq_device,
168 unsigned long cooling_state)
170 unsigned int cpuid, clip_freq;
171 struct cpumask *maskPtr = &cpufreq_device->allowed_cpus;
172 unsigned int cpu = cpumask_any(maskPtr);
175 /* Check if the old cooling action is same as new cooling action */
176 if (cpufreq_device->cpufreq_state == cooling_state)
179 clip_freq = get_cpu_frequency(cpu, cooling_state);
183 cpufreq_device->cpufreq_state = cooling_state;
184 cpufreq_device->cpufreq_val = clip_freq;
185 notify_device = cpufreq_device;
187 for_each_cpu(cpuid, maskPtr) {
188 if (is_cpufreq_valid(cpuid))
189 cpufreq_update_policy(cpuid);
192 notify_device = NOTIFY_INVALID;
198 * cpufreq_thermal_notifier - notifier callback for cpufreq policy change.
199 * @nb: struct notifier_block * with callback info.
200 * @event: value showing cpufreq event for which this function invoked.
201 * @data: callback-specific data
203 static int cpufreq_thermal_notifier(struct notifier_block *nb,
204 unsigned long event, void *data)
206 struct cpufreq_policy *policy = data;
207 unsigned long max_freq = 0;
209 if (event != CPUFREQ_ADJUST || notify_device == NOTIFY_INVALID)
212 if (cpumask_test_cpu(policy->cpu, ¬ify_device->allowed_cpus))
213 max_freq = notify_device->cpufreq_val;
215 /* Never exceed user_policy.max*/
216 if (max_freq > policy->user_policy.max)
217 max_freq = policy->user_policy.max;
219 if (policy->max != max_freq)
220 cpufreq_verify_within_limits(policy, 0, max_freq);
226 * cpufreq cooling device callback functions are defined below
230 * cpufreq_get_max_state - callback function to get the max cooling state.
231 * @cdev: thermal cooling device pointer.
232 * @state: fill this variable with the max cooling state.
234 static int cpufreq_get_max_state(struct thermal_cooling_device *cdev,
235 unsigned long *state)
237 struct cpufreq_cooling_device *cpufreq_device = cdev->devdata;
238 struct cpumask *maskPtr = &cpufreq_device->allowed_cpus;
240 struct cpufreq_frequency_table *table;
241 unsigned long count = 0;
244 cpu = cpumask_any(maskPtr);
245 table = cpufreq_frequency_get_table(cpu);
251 for (i = 0; (table[i].frequency != CPUFREQ_TABLE_END); i++) {
252 if (table[i].frequency == CPUFREQ_ENTRY_INVALID)
266 * cpufreq_get_cur_state - callback function to get the current cooling state.
267 * @cdev: thermal cooling device pointer.
268 * @state: fill this variable with the current cooling state.
270 static int cpufreq_get_cur_state(struct thermal_cooling_device *cdev,
271 unsigned long *state)
273 struct cpufreq_cooling_device *cpufreq_device = cdev->devdata;
275 *state = cpufreq_device->cpufreq_state;
280 * cpufreq_set_cur_state - callback function to set the current cooling state.
281 * @cdev: thermal cooling device pointer.
282 * @state: set this variable to the current cooling state.
284 static int cpufreq_set_cur_state(struct thermal_cooling_device *cdev,
287 struct cpufreq_cooling_device *cpufreq_device = cdev->devdata;
289 return cpufreq_apply_cooling(cpufreq_device, state);
292 /* Bind cpufreq callbacks to thermal cooling device ops */
293 static struct thermal_cooling_device_ops const cpufreq_cooling_ops = {
294 .get_max_state = cpufreq_get_max_state,
295 .get_cur_state = cpufreq_get_cur_state,
296 .set_cur_state = cpufreq_set_cur_state,
299 /* Notifier for cpufreq policy change */
300 static struct notifier_block thermal_cpufreq_notifier_block = {
301 .notifier_call = cpufreq_thermal_notifier,
305 * cpufreq_cooling_register - function to create cpufreq cooling device.
306 * @clip_cpus: cpumask of cpus where the frequency constraints will happen.
308 struct thermal_cooling_device *cpufreq_cooling_register(
309 const struct cpumask *clip_cpus)
311 struct thermal_cooling_device *cool_dev;
312 struct cpufreq_cooling_device *cpufreq_dev = NULL;
313 unsigned int min = 0, max = 0;
314 char dev_name[THERMAL_NAME_LENGTH];
316 struct cpufreq_policy policy;
318 /*Verify that all the clip cpus have same freq_min, freq_max limit*/
319 for_each_cpu(i, clip_cpus) {
320 /*continue if cpufreq policy not found and not return error*/
321 if (!cpufreq_get_policy(&policy, i))
323 if (min == 0 && max == 0) {
324 min = policy.cpuinfo.min_freq;
325 max = policy.cpuinfo.max_freq;
327 if (min != policy.cpuinfo.min_freq ||
328 max != policy.cpuinfo.max_freq)
329 return ERR_PTR(-EINVAL);
332 cpufreq_dev = kzalloc(sizeof(struct cpufreq_cooling_device),
335 return ERR_PTR(-ENOMEM);
337 cpumask_copy(&cpufreq_dev->allowed_cpus, clip_cpus);
339 ret = get_idr(&cpufreq_idr, &cpufreq_dev->id);
342 return ERR_PTR(-EINVAL);
345 sprintf(dev_name, "thermal-cpufreq-%d", cpufreq_dev->id);
347 cool_dev = thermal_cooling_device_register(dev_name, cpufreq_dev,
348 &cpufreq_cooling_ops);
350 release_idr(&cpufreq_idr, cpufreq_dev->id);
352 return ERR_PTR(-EINVAL);
354 cpufreq_dev->cool_dev = cool_dev;
355 cpufreq_dev->cpufreq_state = 0;
356 mutex_lock(&cooling_cpufreq_lock);
358 /* Register the notifier for first cpufreq cooling device */
359 if (cpufreq_dev_count == 0)
360 cpufreq_register_notifier(&thermal_cpufreq_notifier_block,
361 CPUFREQ_POLICY_NOTIFIER);
364 mutex_unlock(&cooling_cpufreq_lock);
367 EXPORT_SYMBOL(cpufreq_cooling_register);
370 * cpufreq_cooling_unregister - function to remove cpufreq cooling device.
371 * @cdev: thermal cooling device pointer.
373 void cpufreq_cooling_unregister(struct thermal_cooling_device *cdev)
375 struct cpufreq_cooling_device *cpufreq_dev = cdev->devdata;
377 mutex_lock(&cooling_cpufreq_lock);
380 /* Unregister the notifier for the last cpufreq cooling device */
381 if (cpufreq_dev_count == 0) {
382 cpufreq_unregister_notifier(&thermal_cpufreq_notifier_block,
383 CPUFREQ_POLICY_NOTIFIER);
385 mutex_unlock(&cooling_cpufreq_lock);
387 thermal_cooling_device_unregister(cpufreq_dev->cool_dev);
388 release_idr(&cpufreq_idr, cpufreq_dev->id);
391 EXPORT_SYMBOL(cpufreq_cooling_unregister);