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1 | /* | |
2 | * linux/drivers/thermal/cpu_cooling.c | |
3 | * | |
4 | * Copyright (C) 2012 Samsung Electronics Co., Ltd(http://www.samsung.com) | |
5 | * Copyright (C) 2012 Amit Daniel <amit.kachhap@linaro.org> | |
6 | * | |
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. | |
11 | * | |
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. | |
16 | * | |
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. | |
20 | * | |
21 | * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ | |
22 | */ | |
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> | |
30 | ||
31 | /** | |
32 | * struct cpufreq_cooling_device - data for cooling device with cpufreq | |
33 | * @id: unique integer value corresponding to each cpufreq_cooling_device | |
34 | * registered. | |
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 | |
38 | * cooling devices. | |
39 | * @cpufreq_val: integer value representing the absolute value of the clipped | |
40 | * frequency. | |
41 | * @allowed_cpus: all the cpus involved for this cpufreq_cooling_device. | |
42 | * | |
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. | |
46 | */ | |
47 | struct cpufreq_cooling_device { | |
48 | int id; | |
49 | struct thermal_cooling_device *cool_dev; | |
50 | unsigned int cpufreq_state; | |
51 | unsigned int cpufreq_val; | |
52 | struct cpumask allowed_cpus; | |
53 | }; | |
54 | static DEFINE_IDR(cpufreq_idr); | |
55 | static DEFINE_MUTEX(cooling_cpufreq_lock); | |
56 | ||
57 | static unsigned int cpufreq_dev_count; | |
58 | ||
59 | /* notify_table passes value to the CPUFREQ_ADJUST callback function. */ | |
60 | #define NOTIFY_INVALID NULL | |
61 | static struct cpufreq_cooling_device *notify_device; | |
62 | ||
63 | /** | |
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. | |
67 | */ | |
68 | static int get_idr(struct idr *idr, int *id) | |
69 | { | |
70 | int ret; | |
71 | ||
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)) | |
76 | return ret; | |
77 | *id = ret; | |
78 | return 0; | |
79 | } | |
80 | ||
81 | /** | |
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. | |
85 | */ | |
86 | static void release_idr(struct idr *idr, int id) | |
87 | { | |
88 | mutex_lock(&cooling_cpufreq_lock); | |
89 | idr_remove(idr, id); | |
90 | mutex_unlock(&cooling_cpufreq_lock); | |
91 | } | |
92 | ||
93 | /* Below code defines functions to be used for cpufreq as cooling device */ | |
94 | ||
95 | /** | |
96 | * is_cpufreq_valid - function to check frequency transitioning capability. | |
97 | * @cpu: cpu for which check is needed. | |
98 | * | |
99 | * This function will check the current state of the system if | |
100 | * it is capable of changing the frequency for a given @cpu. | |
101 | * | |
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. | |
104 | */ | |
105 | static int is_cpufreq_valid(int cpu) | |
106 | { | |
107 | struct cpufreq_policy policy; | |
108 | return !cpufreq_get_policy(&policy, cpu); | |
109 | } | |
110 | ||
111 | enum cpufreq_cooling_property { | |
112 | GET_LEVEL, | |
113 | GET_FREQ, | |
114 | GET_MAXL, | |
115 | }; | |
116 | ||
117 | /** | |
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) | |
123 | * | |
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. | |
133 | * | |
134 | * Return: 0 on success, -EINVAL when invalid parameters are passed. | |
135 | */ | |
136 | static int get_property(unsigned int cpu, unsigned long input, | |
137 | unsigned int* output, enum cpufreq_cooling_property property) | |
138 | { | |
139 | int i, j; | |
140 | unsigned long max_level = 0, level = 0; | |
141 | unsigned int freq = CPUFREQ_ENTRY_INVALID; | |
142 | int descend = -1; | |
143 | struct cpufreq_frequency_table *table = | |
144 | cpufreq_frequency_get_table(cpu); | |
145 | ||
146 | if (!output) | |
147 | return -EINVAL; | |
148 | ||
149 | if (!table) | |
150 | return -EINVAL; | |
151 | ||
152 | for (i = 0; table[i].frequency != CPUFREQ_TABLE_END; i++) { | |
153 | /* ignore invalid entries */ | |
154 | if (table[i].frequency == CPUFREQ_ENTRY_INVALID) | |
155 | continue; | |
156 | ||
157 | /* ignore duplicate entry */ | |
158 | if (freq == table[i].frequency) | |
159 | continue; | |
160 | ||
161 | /* get the frequency order */ | |
162 | if (freq != CPUFREQ_ENTRY_INVALID && descend != -1) | |
163 | descend = !!(freq > table[i].frequency); | |
164 | ||
165 | freq = table[i].frequency; | |
166 | max_level++; | |
167 | } | |
168 | ||
169 | /* get max level */ | |
170 | if (property == GET_MAXL) { | |
171 | *output = (unsigned int)max_level; | |
172 | return 0; | |
173 | } | |
174 | ||
175 | if (property == GET_FREQ) | |
176 | level = descend ? input : (max_level - input -1); | |
177 | ||
178 | ||
179 | for (i = 0, j = 0; table[i].frequency != CPUFREQ_TABLE_END; i++) { | |
180 | /* ignore invalid entry */ | |
181 | if (table[i].frequency == CPUFREQ_ENTRY_INVALID) | |
182 | continue; | |
183 | ||
184 | /* ignore duplicate entry */ | |
185 | if (freq == table[i].frequency) | |
186 | continue; | |
187 | ||
188 | /* now we have a valid frequency entry */ | |
189 | freq = table[i].frequency; | |
190 | ||
191 | if (property == GET_LEVEL && (unsigned int)input == freq) { | |
192 | /* get level by frequency */ | |
193 | *output = descend ? j : (max_level - j - 1); | |
194 | return 0; | |
195 | } | |
196 | if (property == GET_FREQ && level == j) { | |
197 | /* get frequency by level */ | |
198 | *output = freq; | |
199 | return 0; | |
200 | } | |
201 | j++; | |
202 | } | |
203 | return -EINVAL; | |
204 | } | |
205 | ||
206 | /** | |
207 | * cpufreq_cooling_get_level - for a give cpu, return the cooling level. | |
208 | * @cpu: cpu for which the level is required | |
209 | * @freq: the frequency of interest | |
210 | * | |
211 | * This function will match the cooling level corresponding to the | |
212 | * requested @freq and return it. | |
213 | * | |
214 | * Return: The matched cooling level on success or THERMAL_CSTATE_INVALID | |
215 | * otherwise. | |
216 | */ | |
217 | unsigned long cpufreq_cooling_get_level(unsigned int cpu, unsigned int freq) | |
218 | { | |
219 | unsigned int val; | |
220 | ||
221 | if (get_property(cpu, (unsigned long)freq, &val, GET_LEVEL)) | |
222 | return THERMAL_CSTATE_INVALID; | |
223 | return (unsigned long)val; | |
224 | } | |
225 | EXPORT_SYMBOL_GPL(cpufreq_cooling_get_level); | |
226 | ||
227 | /** | |
228 | * get_cpu_frequency - get the absolute value of frequency from level. | |
229 | * @cpu: cpu for which frequency is fetched. | |
230 | * @level: cooling level | |
231 | * | |
232 | * This function matches cooling level with frequency. Based on a cooling level | |
233 | * of frequency, equals cooling state of cpu cooling device, it will return | |
234 | * the corresponding frequency. | |
235 | * e.g level=0 --> 1st MAX FREQ, level=1 ---> 2nd MAX FREQ, .... etc | |
236 | * | |
237 | * Return: 0 on error, the corresponding frequency otherwise. | |
238 | */ | |
239 | static unsigned int get_cpu_frequency(unsigned int cpu, unsigned long level) | |
240 | { | |
241 | int ret = 0; | |
242 | unsigned int freq; | |
243 | ||
244 | ret = get_property(cpu, level, &freq, GET_FREQ); | |
245 | if (ret) | |
246 | return 0; | |
247 | return freq; | |
248 | } | |
249 | ||
250 | /** | |
251 | * cpufreq_apply_cooling - function to apply frequency clipping. | |
252 | * @cpufreq_device: cpufreq_cooling_device pointer containing frequency | |
253 | * clipping data. | |
254 | * @cooling_state: value of the cooling state. | |
255 | * | |
256 | * Function used to make sure the cpufreq layer is aware of current thermal | |
257 | * limits. The limits are applied by updating the cpufreq policy. | |
258 | * | |
259 | * Return: 0 on success, an error code otherwise (-EINVAL in case wrong | |
260 | * cooling state). | |
261 | */ | |
262 | static int cpufreq_apply_cooling(struct cpufreq_cooling_device *cpufreq_device, | |
263 | unsigned long cooling_state) | |
264 | { | |
265 | unsigned int cpuid, clip_freq; | |
266 | struct cpumask *mask = &cpufreq_device->allowed_cpus; | |
267 | unsigned int cpu = cpumask_any(mask); | |
268 | ||
269 | ||
270 | /* Check if the old cooling action is same as new cooling action */ | |
271 | if (cpufreq_device->cpufreq_state == cooling_state) | |
272 | return 0; | |
273 | ||
274 | clip_freq = get_cpu_frequency(cpu, cooling_state); | |
275 | if (!clip_freq) | |
276 | return -EINVAL; | |
277 | ||
278 | cpufreq_device->cpufreq_state = cooling_state; | |
279 | cpufreq_device->cpufreq_val = clip_freq; | |
280 | notify_device = cpufreq_device; | |
281 | ||
282 | for_each_cpu(cpuid, mask) { | |
283 | if (is_cpufreq_valid(cpuid)) | |
284 | cpufreq_update_policy(cpuid); | |
285 | } | |
286 | ||
287 | notify_device = NOTIFY_INVALID; | |
288 | ||
289 | return 0; | |
290 | } | |
291 | ||
292 | /** | |
293 | * cpufreq_thermal_notifier - notifier callback for cpufreq policy change. | |
294 | * @nb: struct notifier_block * with callback info. | |
295 | * @event: value showing cpufreq event for which this function invoked. | |
296 | * @data: callback-specific data | |
297 | * | |
298 | * Callback to highjack the notification on cpufreq policy transition. | |
299 | * Every time there is a change in policy, we will intercept and | |
300 | * update the cpufreq policy with thermal constraints. | |
301 | * | |
302 | * Return: 0 (success) | |
303 | */ | |
304 | static int cpufreq_thermal_notifier(struct notifier_block *nb, | |
305 | unsigned long event, void *data) | |
306 | { | |
307 | struct cpufreq_policy *policy = data; | |
308 | unsigned long max_freq = 0; | |
309 | ||
310 | if (event != CPUFREQ_ADJUST || notify_device == NOTIFY_INVALID) | |
311 | return 0; | |
312 | ||
313 | if (cpumask_test_cpu(policy->cpu, ¬ify_device->allowed_cpus)) | |
314 | max_freq = notify_device->cpufreq_val; | |
315 | ||
316 | /* Never exceed user_policy.max*/ | |
317 | if (max_freq > policy->user_policy.max) | |
318 | max_freq = policy->user_policy.max; | |
319 | ||
320 | if (policy->max != max_freq) | |
321 | cpufreq_verify_within_limits(policy, 0, max_freq); | |
322 | ||
323 | return 0; | |
324 | } | |
325 | ||
326 | /* | |
327 | * cpufreq cooling device callback functions are defined below | |
328 | */ | |
329 | ||
330 | /** | |
331 | * cpufreq_get_max_state - callback function to get the max cooling state. | |
332 | * @cdev: thermal cooling device pointer. | |
333 | * @state: fill this variable with the max cooling state. | |
334 | * | |
335 | * Callback for the thermal cooling device to return the cpufreq | |
336 | * max cooling state. | |
337 | * | |
338 | * Return: 0 on success, an error code otherwise. | |
339 | */ | |
340 | static int cpufreq_get_max_state(struct thermal_cooling_device *cdev, | |
341 | unsigned long *state) | |
342 | { | |
343 | struct cpufreq_cooling_device *cpufreq_device = cdev->devdata; | |
344 | struct cpumask *mask = &cpufreq_device->allowed_cpus; | |
345 | unsigned int cpu; | |
346 | unsigned int count = 0; | |
347 | int ret; | |
348 | ||
349 | cpu = cpumask_any(mask); | |
350 | ||
351 | ret = get_property(cpu, 0, &count, GET_MAXL); | |
352 | ||
353 | if (count > 0) | |
354 | *state = count; | |
355 | ||
356 | return ret; | |
357 | } | |
358 | ||
359 | /** | |
360 | * cpufreq_get_cur_state - callback function to get the current cooling state. | |
361 | * @cdev: thermal cooling device pointer. | |
362 | * @state: fill this variable with the current cooling state. | |
363 | * | |
364 | * Callback for the thermal cooling device to return the cpufreq | |
365 | * current cooling state. | |
366 | * | |
367 | * Return: 0 on success, an error code otherwise. | |
368 | */ | |
369 | static int cpufreq_get_cur_state(struct thermal_cooling_device *cdev, | |
370 | unsigned long *state) | |
371 | { | |
372 | struct cpufreq_cooling_device *cpufreq_device = cdev->devdata; | |
373 | ||
374 | *state = cpufreq_device->cpufreq_state; | |
375 | return 0; | |
376 | } | |
377 | ||
378 | /** | |
379 | * cpufreq_set_cur_state - callback function to set the current cooling state. | |
380 | * @cdev: thermal cooling device pointer. | |
381 | * @state: set this variable to the current cooling state. | |
382 | * | |
383 | * Callback for the thermal cooling device to change the cpufreq | |
384 | * current cooling state. | |
385 | * | |
386 | * Return: 0 on success, an error code otherwise. | |
387 | */ | |
388 | static int cpufreq_set_cur_state(struct thermal_cooling_device *cdev, | |
389 | unsigned long state) | |
390 | { | |
391 | struct cpufreq_cooling_device *cpufreq_device = cdev->devdata; | |
392 | ||
393 | return cpufreq_apply_cooling(cpufreq_device, state); | |
394 | } | |
395 | ||
396 | /* Bind cpufreq callbacks to thermal cooling device ops */ | |
397 | static struct thermal_cooling_device_ops const cpufreq_cooling_ops = { | |
398 | .get_max_state = cpufreq_get_max_state, | |
399 | .get_cur_state = cpufreq_get_cur_state, | |
400 | .set_cur_state = cpufreq_set_cur_state, | |
401 | }; | |
402 | ||
403 | /* Notifier for cpufreq policy change */ | |
404 | static struct notifier_block thermal_cpufreq_notifier_block = { | |
405 | .notifier_call = cpufreq_thermal_notifier, | |
406 | }; | |
407 | ||
408 | /** | |
409 | * cpufreq_cooling_register - function to create cpufreq cooling device. | |
410 | * @clip_cpus: cpumask of cpus where the frequency constraints will happen. | |
411 | * | |
412 | * This interface function registers the cpufreq cooling device with the name | |
413 | * "thermal-cpufreq-%x". This api can support multiple instances of cpufreq | |
414 | * cooling devices. | |
415 | * | |
416 | * Return: a valid struct thermal_cooling_device pointer on success, | |
417 | * on failure, it returns a corresponding ERR_PTR(). | |
418 | */ | |
419 | struct thermal_cooling_device *cpufreq_cooling_register( | |
420 | const struct cpumask *clip_cpus) | |
421 | { | |
422 | struct thermal_cooling_device *cool_dev; | |
423 | struct cpufreq_cooling_device *cpufreq_dev = NULL; | |
424 | unsigned int min = 0, max = 0; | |
425 | char dev_name[THERMAL_NAME_LENGTH]; | |
426 | int ret = 0, i; | |
427 | struct cpufreq_policy policy; | |
428 | ||
429 | /*Verify that all the clip cpus have same freq_min, freq_max limit*/ | |
430 | for_each_cpu(i, clip_cpus) { | |
431 | /*continue if cpufreq policy not found and not return error*/ | |
432 | if (!cpufreq_get_policy(&policy, i)) | |
433 | continue; | |
434 | if (min == 0 && max == 0) { | |
435 | min = policy.cpuinfo.min_freq; | |
436 | max = policy.cpuinfo.max_freq; | |
437 | } else { | |
438 | if (min != policy.cpuinfo.min_freq || | |
439 | max != policy.cpuinfo.max_freq) | |
440 | return ERR_PTR(-EINVAL); | |
441 | } | |
442 | } | |
443 | cpufreq_dev = kzalloc(sizeof(struct cpufreq_cooling_device), | |
444 | GFP_KERNEL); | |
445 | if (!cpufreq_dev) | |
446 | return ERR_PTR(-ENOMEM); | |
447 | ||
448 | cpumask_copy(&cpufreq_dev->allowed_cpus, clip_cpus); | |
449 | ||
450 | ret = get_idr(&cpufreq_idr, &cpufreq_dev->id); | |
451 | if (ret) { | |
452 | kfree(cpufreq_dev); | |
453 | return ERR_PTR(-EINVAL); | |
454 | } | |
455 | ||
456 | snprintf(dev_name, sizeof(dev_name), "thermal-cpufreq-%d", | |
457 | cpufreq_dev->id); | |
458 | ||
459 | cool_dev = thermal_cooling_device_register(dev_name, cpufreq_dev, | |
460 | &cpufreq_cooling_ops); | |
461 | if (!cool_dev) { | |
462 | release_idr(&cpufreq_idr, cpufreq_dev->id); | |
463 | kfree(cpufreq_dev); | |
464 | return ERR_PTR(-EINVAL); | |
465 | } | |
466 | cpufreq_dev->cool_dev = cool_dev; | |
467 | cpufreq_dev->cpufreq_state = 0; | |
468 | mutex_lock(&cooling_cpufreq_lock); | |
469 | ||
470 | /* Register the notifier for first cpufreq cooling device */ | |
471 | if (cpufreq_dev_count == 0) | |
472 | cpufreq_register_notifier(&thermal_cpufreq_notifier_block, | |
473 | CPUFREQ_POLICY_NOTIFIER); | |
474 | cpufreq_dev_count++; | |
475 | ||
476 | mutex_unlock(&cooling_cpufreq_lock); | |
477 | return cool_dev; | |
478 | } | |
479 | EXPORT_SYMBOL_GPL(cpufreq_cooling_register); | |
480 | ||
481 | /** | |
482 | * cpufreq_cooling_unregister - function to remove cpufreq cooling device. | |
483 | * @cdev: thermal cooling device pointer. | |
484 | * | |
485 | * This interface function unregisters the "thermal-cpufreq-%x" cooling device. | |
486 | */ | |
487 | void cpufreq_cooling_unregister(struct thermal_cooling_device *cdev) | |
488 | { | |
489 | struct cpufreq_cooling_device *cpufreq_dev = cdev->devdata; | |
490 | ||
491 | mutex_lock(&cooling_cpufreq_lock); | |
492 | cpufreq_dev_count--; | |
493 | ||
494 | /* Unregister the notifier for the last cpufreq cooling device */ | |
495 | if (cpufreq_dev_count == 0) | |
496 | cpufreq_unregister_notifier(&thermal_cpufreq_notifier_block, | |
497 | CPUFREQ_POLICY_NOTIFIER); | |
498 | ||
499 | mutex_unlock(&cooling_cpufreq_lock); | |
500 | ||
501 | thermal_cooling_device_unregister(cpufreq_dev->cool_dev); | |
502 | release_idr(&cpufreq_idr, cpufreq_dev->id); | |
503 | kfree(cpufreq_dev); | |
504 | } | |
505 | EXPORT_SYMBOL_GPL(cpufreq_cooling_unregister); |