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
);