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.
43 * This structure is required for keeping information of each
44 * cpufreq_cooling_device registered. In order to prevent corruption of this a
45 * mutex lock cooling_cpufreq_lock is used.
47 struct cpufreq_cooling_device
{
49 struct thermal_cooling_device
*cool_dev
;
50 unsigned int cpufreq_state
;
51 unsigned int cpufreq_val
;
52 struct cpumask allowed_cpus
;
54 static DEFINE_IDR(cpufreq_idr
);
55 static DEFINE_MUTEX(cooling_cpufreq_lock
);
57 static unsigned int cpufreq_dev_count
;
59 /* notify_table passes value to the CPUFREQ_ADJUST callback function. */
60 #define NOTIFY_INVALID NULL
61 static struct cpufreq_cooling_device
*notify_device
;
64 * get_idr - function to get a unique id.
65 * @idr: struct idr * handle used to create a id.
66 * @id: int * value generated by this function.
68 static int get_idr(struct idr
*idr
, int *id
)
72 mutex_lock(&cooling_cpufreq_lock
);
73 ret
= idr_alloc(idr
, NULL
, 0, 0, GFP_KERNEL
);
74 mutex_unlock(&cooling_cpufreq_lock
);
75 if (unlikely(ret
< 0))
82 * release_idr - function to free the unique id.
83 * @idr: struct idr * handle used for creating the id.
84 * @id: int value representing the unique id.
86 static void release_idr(struct idr
*idr
, int id
)
88 mutex_lock(&cooling_cpufreq_lock
);
90 mutex_unlock(&cooling_cpufreq_lock
);
93 /* Below code defines functions to be used for cpufreq as cooling device */
96 * is_cpufreq_valid - function to check frequency transitioning capability.
97 * @cpu: cpu for which check is needed.
99 * This function will check the current state of the system if
100 * it is capable of changing the frequency for a given @cpu.
102 * Return: 0 if the system is not currently capable of changing
103 * the frequency of given cpu. !0 in case the frequency is changeable.
105 static int is_cpufreq_valid(int cpu
)
107 struct cpufreq_policy policy
;
108 return !cpufreq_get_policy(&policy
, cpu
);
111 enum cpufreq_cooling_property
{
118 * get_property - fetch a property of interest for a give cpu.
119 * @cpu: cpu for which the property is required
120 * @input: query parameter
121 * @output: query return
122 * @property: type of query (frequency, level, max level)
124 * This is the common function to
125 * 1. get maximum cpu cooling states
126 * 2. translate frequency to cooling state
127 * 3. translate cooling state to frequency
128 * Note that the code may be not in good shape
129 * but it is written in this way in order to:
130 * a) reduce duplicate code as most of the code can be shared.
131 * b) make sure the logic is consistent when translating between
132 * cooling states and frequencies.
134 * Return: 0 on success, -EINVAL when invalid parameters are passed.
136 static int get_property(unsigned int cpu
, unsigned long input
,
137 unsigned int* output
, enum cpufreq_cooling_property property
)
140 unsigned long max_level
= 0, level
= 0;
141 unsigned int freq
= CPUFREQ_ENTRY_INVALID
;
143 struct cpufreq_frequency_table
*table
=
144 cpufreq_frequency_get_table(cpu
);
153 for (i
= 0; table
[i
].frequency
!= CPUFREQ_TABLE_END
; i
++) {
154 /* ignore invalid entries */
155 if (table
[i
].frequency
== CPUFREQ_ENTRY_INVALID
)
158 /* ignore duplicate entry */
159 if (freq
== table
[i
].frequency
)
162 /* get the frequency order */
163 if (freq
!= CPUFREQ_ENTRY_INVALID
&& descend
!= -1)
164 descend
= !!(freq
> table
[i
].frequency
);
166 freq
= table
[i
].frequency
;
171 if (property
== GET_MAXL
) {
172 *output
= (unsigned int)max_level
;
176 if (property
== GET_FREQ
)
177 level
= descend
? input
: (max_level
- input
-1);
180 for (i
= 0, j
= 0; table
[i
].frequency
!= CPUFREQ_TABLE_END
; i
++) {
181 /* ignore invalid entry */
182 if (table
[i
].frequency
== CPUFREQ_ENTRY_INVALID
)
185 /* ignore duplicate entry */
186 if (freq
== table
[i
].frequency
)
189 /* now we have a valid frequency entry */
190 freq
= table
[i
].frequency
;
192 if (property
== GET_LEVEL
&& (unsigned int)input
== freq
) {
193 /* get level by frequency */
194 *output
= descend
? j
: (max_level
- j
- 1);
197 if (property
== GET_FREQ
&& level
== j
) {
198 /* get frequency by level */
208 * cpufreq_cooling_get_level - for a give cpu, return the cooling level.
209 * @cpu: cpu for which the level is required
210 * @freq: the frequency of interest
212 * This function will match the cooling level corresponding to the
213 * requested @freq and return it.
215 * Return: The matched cooling level on success or THERMAL_CSTATE_INVALID
218 unsigned long cpufreq_cooling_get_level(unsigned int cpu
, unsigned int freq
)
222 if (get_property(cpu
, (unsigned long)freq
, &val
, GET_LEVEL
))
223 return THERMAL_CSTATE_INVALID
;
224 return (unsigned long)val
;
226 EXPORT_SYMBOL_GPL(cpufreq_cooling_get_level
);
229 * get_cpu_frequency - get the absolute value of frequency from level.
230 * @cpu: cpu for which frequency is fetched.
231 * @level: cooling level
233 * This function matches cooling level with frequency. Based on a cooling level
234 * of frequency, equals cooling state of cpu cooling device, it will return
235 * the corresponding frequency.
236 * e.g level=0 --> 1st MAX FREQ, level=1 ---> 2nd MAX FREQ, .... etc
238 * Return: 0 on error, the corresponding frequency otherwise.
240 static unsigned int get_cpu_frequency(unsigned int cpu
, unsigned long level
)
245 ret
= get_property(cpu
, level
, &freq
, GET_FREQ
);
252 * cpufreq_apply_cooling - function to apply frequency clipping.
253 * @cpufreq_device: cpufreq_cooling_device pointer containing frequency
255 * @cooling_state: value of the cooling state.
257 * Function used to make sure the cpufreq layer is aware of current thermal
258 * limits. The limits are applied by updating the cpufreq policy.
260 * Return: 0 on success, an error code otherwise (-EINVAL in case wrong
263 static int cpufreq_apply_cooling(struct cpufreq_cooling_device
*cpufreq_device
,
264 unsigned long cooling_state
)
266 unsigned int cpuid
, clip_freq
;
267 struct cpumask
*mask
= &cpufreq_device
->allowed_cpus
;
268 unsigned int cpu
= cpumask_any(mask
);
271 /* Check if the old cooling action is same as new cooling action */
272 if (cpufreq_device
->cpufreq_state
== cooling_state
)
275 clip_freq
= get_cpu_frequency(cpu
, cooling_state
);
279 cpufreq_device
->cpufreq_state
= cooling_state
;
280 cpufreq_device
->cpufreq_val
= clip_freq
;
281 notify_device
= cpufreq_device
;
283 for_each_cpu(cpuid
, mask
) {
284 if (is_cpufreq_valid(cpuid
))
285 cpufreq_update_policy(cpuid
);
288 notify_device
= NOTIFY_INVALID
;
294 * cpufreq_thermal_notifier - notifier callback for cpufreq policy change.
295 * @nb: struct notifier_block * with callback info.
296 * @event: value showing cpufreq event for which this function invoked.
297 * @data: callback-specific data
299 * Callback to highjack the notification on cpufreq policy transition.
300 * Every time there is a change in policy, we will intercept and
301 * update the cpufreq policy with thermal constraints.
303 * Return: 0 (success)
305 static int cpufreq_thermal_notifier(struct notifier_block
*nb
,
306 unsigned long event
, void *data
)
308 struct cpufreq_policy
*policy
= data
;
309 unsigned long max_freq
= 0;
311 if (event
!= CPUFREQ_ADJUST
|| notify_device
== NOTIFY_INVALID
)
314 if (cpumask_test_cpu(policy
->cpu
, ¬ify_device
->allowed_cpus
))
315 max_freq
= notify_device
->cpufreq_val
;
317 /* Never exceed user_policy.max*/
318 if (max_freq
> policy
->user_policy
.max
)
319 max_freq
= policy
->user_policy
.max
;
321 if (policy
->max
!= max_freq
)
322 cpufreq_verify_within_limits(policy
, 0, max_freq
);
328 * cpufreq cooling device callback functions are defined below
332 * cpufreq_get_max_state - callback function to get the max cooling state.
333 * @cdev: thermal cooling device pointer.
334 * @state: fill this variable with the max cooling state.
336 * Callback for the thermal cooling device to return the cpufreq
339 * Return: 0 on success, an error code otherwise.
341 static int cpufreq_get_max_state(struct thermal_cooling_device
*cdev
,
342 unsigned long *state
)
344 struct cpufreq_cooling_device
*cpufreq_device
= cdev
->devdata
;
345 struct cpumask
*mask
= &cpufreq_device
->allowed_cpus
;
347 unsigned int count
= 0;
350 cpu
= cpumask_any(mask
);
352 ret
= get_property(cpu
, 0, &count
, GET_MAXL
);
361 * cpufreq_get_cur_state - callback function to get the current cooling state.
362 * @cdev: thermal cooling device pointer.
363 * @state: fill this variable with the current cooling state.
365 * Callback for the thermal cooling device to return the cpufreq
366 * current cooling state.
368 * Return: 0 on success, an error code otherwise.
370 static int cpufreq_get_cur_state(struct thermal_cooling_device
*cdev
,
371 unsigned long *state
)
373 struct cpufreq_cooling_device
*cpufreq_device
= cdev
->devdata
;
375 *state
= cpufreq_device
->cpufreq_state
;
380 * cpufreq_set_cur_state - callback function to set the current cooling state.
381 * @cdev: thermal cooling device pointer.
382 * @state: set this variable to the current cooling state.
384 * Callback for the thermal cooling device to change the cpufreq
385 * current cooling state.
387 * Return: 0 on success, an error code otherwise.
389 static int cpufreq_set_cur_state(struct thermal_cooling_device
*cdev
,
392 struct cpufreq_cooling_device
*cpufreq_device
= cdev
->devdata
;
394 return cpufreq_apply_cooling(cpufreq_device
, state
);
397 /* Bind cpufreq callbacks to thermal cooling device ops */
398 static struct thermal_cooling_device_ops
const cpufreq_cooling_ops
= {
399 .get_max_state
= cpufreq_get_max_state
,
400 .get_cur_state
= cpufreq_get_cur_state
,
401 .set_cur_state
= cpufreq_set_cur_state
,
404 /* Notifier for cpufreq policy change */
405 static struct notifier_block thermal_cpufreq_notifier_block
= {
406 .notifier_call
= cpufreq_thermal_notifier
,
410 * cpufreq_cooling_register - function to create cpufreq cooling device.
411 * @clip_cpus: cpumask of cpus where the frequency constraints will happen.
413 * This interface function registers the cpufreq cooling device with the name
414 * "thermal-cpufreq-%x". This api can support multiple instances of cpufreq
417 * Return: a valid struct thermal_cooling_device pointer on success,
418 * on failure, it returns a corresponding ERR_PTR().
420 struct thermal_cooling_device
*cpufreq_cooling_register(
421 const struct cpumask
*clip_cpus
)
423 struct thermal_cooling_device
*cool_dev
;
424 struct cpufreq_cooling_device
*cpufreq_dev
= NULL
;
425 unsigned int min
= 0, max
= 0;
426 char dev_name
[THERMAL_NAME_LENGTH
];
428 struct cpufreq_policy policy
;
430 /*Verify that all the clip cpus have same freq_min, freq_max limit*/
431 for_each_cpu(i
, clip_cpus
) {
432 /*continue if cpufreq policy not found and not return error*/
433 if (!cpufreq_get_policy(&policy
, i
))
435 if (min
== 0 && max
== 0) {
436 min
= policy
.cpuinfo
.min_freq
;
437 max
= policy
.cpuinfo
.max_freq
;
439 if (min
!= policy
.cpuinfo
.min_freq
||
440 max
!= policy
.cpuinfo
.max_freq
)
441 return ERR_PTR(-EINVAL
);
444 cpufreq_dev
= kzalloc(sizeof(struct cpufreq_cooling_device
),
447 return ERR_PTR(-ENOMEM
);
449 cpumask_copy(&cpufreq_dev
->allowed_cpus
, clip_cpus
);
451 ret
= get_idr(&cpufreq_idr
, &cpufreq_dev
->id
);
454 return ERR_PTR(-EINVAL
);
457 snprintf(dev_name
, sizeof(dev_name
), "thermal-cpufreq-%d",
460 cool_dev
= thermal_cooling_device_register(dev_name
, cpufreq_dev
,
461 &cpufreq_cooling_ops
);
463 release_idr(&cpufreq_idr
, cpufreq_dev
->id
);
465 return ERR_PTR(-EINVAL
);
467 cpufreq_dev
->cool_dev
= cool_dev
;
468 cpufreq_dev
->cpufreq_state
= 0;
469 mutex_lock(&cooling_cpufreq_lock
);
471 /* Register the notifier for first cpufreq cooling device */
472 if (cpufreq_dev_count
== 0)
473 cpufreq_register_notifier(&thermal_cpufreq_notifier_block
,
474 CPUFREQ_POLICY_NOTIFIER
);
477 mutex_unlock(&cooling_cpufreq_lock
);
480 EXPORT_SYMBOL_GPL(cpufreq_cooling_register
);
483 * cpufreq_cooling_unregister - function to remove cpufreq cooling device.
484 * @cdev: thermal cooling device pointer.
486 * This interface function unregisters the "thermal-cpufreq-%x" cooling device.
488 void cpufreq_cooling_unregister(struct thermal_cooling_device
*cdev
)
490 struct cpufreq_cooling_device
*cpufreq_dev
= cdev
->devdata
;
492 mutex_lock(&cooling_cpufreq_lock
);
495 /* Unregister the notifier for the last cpufreq cooling device */
496 if (cpufreq_dev_count
== 0)
497 cpufreq_unregister_notifier(&thermal_cpufreq_notifier_block
,
498 CPUFREQ_POLICY_NOTIFIER
);
500 mutex_unlock(&cooling_cpufreq_lock
);
502 thermal_cooling_device_unregister(cpufreq_dev
->cool_dev
);
503 release_idr(&cpufreq_idr
, cpufreq_dev
->id
);
506 EXPORT_SYMBOL_GPL(cpufreq_cooling_unregister
);