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1 | /* |
2 | * drivers/thermal/clock_cooling.c | |
3 | * | |
4 | * Copyright (C) 2014 Eduardo Valentin <edubezval@gmail.com> | |
5 | * | |
6 | * Copyright (C) 2013 Texas Instruments Inc. | |
7 | * Contact: Eduardo Valentin <eduardo.valentin@ti.com> | |
8 | * | |
9 | * Highly based on cpu_cooling.c. | |
10 | * Copyright (C) 2012 Samsung Electronics Co., Ltd(http://www.samsung.com) | |
11 | * Copyright (C) 2012 Amit Daniel <amit.kachhap@linaro.org> | |
12 | * | |
13 | * This program is free software; you can redistribute it and/or modify | |
14 | * it under the terms of the GNU General Public License as published by | |
15 | * the Free Software Foundation; version 2 of the License. | |
16 | * | |
17 | * This program is distributed in the hope that it will be useful, but | |
18 | * WITHOUT ANY WARRANTY; without even the implied warranty of | |
19 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
20 | * General Public License for more details. | |
21 | */ | |
22 | #include <linux/clk.h> | |
23 | #include <linux/cpufreq.h> | |
24 | #include <linux/device.h> | |
25 | #include <linux/err.h> | |
26 | #include <linux/idr.h> | |
27 | #include <linux/mutex.h> | |
28 | #include <linux/pm_opp.h> | |
29 | #include <linux/slab.h> | |
30 | #include <linux/thermal.h> | |
31 | #include <linux/clock_cooling.h> | |
32 | ||
33 | /** | |
34 | * struct clock_cooling_device - data for cooling device with clock | |
35 | * @id: unique integer value corresponding to each clock_cooling_device | |
36 | * registered. | |
37 | * @dev: struct device pointer to the device being used to cool off using | |
38 | * clock frequencies. | |
39 | * @cdev: thermal_cooling_device pointer to keep track of the | |
40 | * registered cooling device. | |
41 | * @clk_rate_change_nb: reference to notifier block used to receive clock | |
42 | * rate changes. | |
43 | * @freq_table: frequency table used to keep track of available frequencies. | |
44 | * @clock_state: integer value representing the current state of clock | |
45 | * cooling devices. | |
46 | * @clock_val: integer value representing the absolute value of the clipped | |
47 | * frequency. | |
48 | * @clk: struct clk reference used to enforce clock limits. | |
49 | * @lock: mutex lock to protect this struct. | |
50 | * | |
51 | * This structure is required for keeping information of each | |
52 | * clock_cooling_device registered. In order to prevent corruption of this a | |
53 | * mutex @lock is used. | |
54 | */ | |
55 | struct clock_cooling_device { | |
56 | int id; | |
57 | struct device *dev; | |
58 | struct thermal_cooling_device *cdev; | |
59 | struct notifier_block clk_rate_change_nb; | |
60 | struct cpufreq_frequency_table *freq_table; | |
61 | unsigned long clock_state; | |
62 | unsigned long clock_val; | |
63 | struct clk *clk; | |
64 | struct mutex lock; /* lock to protect the content of this struct */ | |
65 | }; | |
66 | #define to_clock_cooling_device(x) \ | |
67 | container_of(x, struct clock_cooling_device, clk_rate_change_nb) | |
68 | static DEFINE_IDR(clock_idr); | |
69 | static DEFINE_MUTEX(cooling_clock_lock); | |
70 | ||
71 | /** | |
72 | * clock_cooling_get_idr - function to get an unique id. | |
73 | * @id: int * value generated by this function. | |
74 | * | |
75 | * This function will populate @id with an unique | |
76 | * id, using the idr API. | |
77 | * | |
78 | * Return: 0 on success, an error code on failure. | |
79 | */ | |
80 | static int clock_cooling_get_idr(int *id) | |
81 | { | |
82 | int ret; | |
83 | ||
84 | mutex_lock(&cooling_clock_lock); | |
85 | ret = idr_alloc(&clock_idr, NULL, 0, 0, GFP_KERNEL); | |
86 | mutex_unlock(&cooling_clock_lock); | |
87 | if (unlikely(ret < 0)) | |
88 | return ret; | |
89 | *id = ret; | |
90 | ||
91 | return 0; | |
92 | } | |
93 | ||
94 | /** | |
95 | * release_idr - function to free the unique id. | |
96 | * @id: int value representing the unique id. | |
97 | */ | |
98 | static void release_idr(int id) | |
99 | { | |
100 | mutex_lock(&cooling_clock_lock); | |
101 | idr_remove(&clock_idr, id); | |
102 | mutex_unlock(&cooling_clock_lock); | |
103 | } | |
104 | ||
105 | /* Below code defines functions to be used for clock as cooling device */ | |
106 | ||
107 | enum clock_cooling_property { | |
108 | GET_LEVEL, | |
109 | GET_FREQ, | |
110 | GET_MAXL, | |
111 | }; | |
112 | ||
113 | /** | |
114 | * clock_cooling_get_property - fetch a property of interest for a give cpu. | |
115 | * @ccdev: clock cooling device reference | |
116 | * @input: query parameter | |
117 | * @output: query return | |
118 | * @property: type of query (frequency, level, max level) | |
119 | * | |
120 | * This is the common function to | |
121 | * 1. get maximum clock cooling states | |
122 | * 2. translate frequency to cooling state | |
123 | * 3. translate cooling state to frequency | |
124 | * Note that the code may be not in good shape | |
125 | * but it is written in this way in order to: | |
126 | * a) reduce duplicate code as most of the code can be shared. | |
127 | * b) make sure the logic is consistent when translating between | |
128 | * cooling states and frequencies. | |
129 | * | |
130 | * Return: 0 on success, -EINVAL when invalid parameters are passed. | |
131 | */ | |
132 | static int clock_cooling_get_property(struct clock_cooling_device *ccdev, | |
133 | unsigned long input, | |
134 | unsigned long *output, | |
135 | enum clock_cooling_property property) | |
136 | { | |
137 | int i; | |
138 | unsigned long max_level = 0, level = 0; | |
139 | unsigned int freq = CPUFREQ_ENTRY_INVALID; | |
140 | int descend = -1; | |
141 | struct cpufreq_frequency_table *pos, *table = ccdev->freq_table; | |
142 | ||
143 | if (!output) | |
144 | return -EINVAL; | |
145 | ||
146 | if (!table) | |
147 | return -EINVAL; | |
148 | ||
149 | cpufreq_for_each_valid_entry(pos, table) { | |
150 | /* ignore duplicate entry */ | |
151 | if (freq == pos->frequency) | |
152 | continue; | |
153 | ||
154 | /* get the frequency order */ | |
155 | if (freq != CPUFREQ_ENTRY_INVALID && descend == -1) | |
156 | descend = freq > pos->frequency; | |
157 | ||
158 | freq = pos->frequency; | |
159 | max_level++; | |
160 | } | |
161 | ||
162 | /* No valid cpu frequency entry */ | |
163 | if (max_level == 0) | |
164 | return -EINVAL; | |
165 | ||
166 | /* max_level is an index, not a counter */ | |
167 | max_level--; | |
168 | ||
169 | /* get max level */ | |
170 | if (property == GET_MAXL) { | |
171 | *output = max_level; | |
172 | return 0; | |
173 | } | |
174 | ||
175 | if (property == GET_FREQ) | |
176 | level = descend ? input : (max_level - input); | |
177 | ||
178 | i = 0; | |
179 | cpufreq_for_each_valid_entry(pos, table) { | |
180 | /* ignore duplicate entry */ | |
181 | if (freq == pos->frequency) | |
182 | continue; | |
183 | ||
184 | /* now we have a valid frequency entry */ | |
185 | freq = pos->frequency; | |
186 | ||
187 | if (property == GET_LEVEL && (unsigned int)input == freq) { | |
188 | /* get level by frequency */ | |
189 | *output = descend ? i : (max_level - i); | |
190 | return 0; | |
191 | } | |
192 | if (property == GET_FREQ && level == i) { | |
193 | /* get frequency by level */ | |
194 | *output = freq; | |
195 | return 0; | |
196 | } | |
197 | i++; | |
198 | } | |
199 | ||
200 | return -EINVAL; | |
201 | } | |
202 | ||
203 | /** | |
204 | * clock_cooling_get_level - return the cooling level of given clock cooling. | |
205 | * @cdev: reference of a thermal cooling device of used as clock cooling device | |
206 | * @freq: the frequency of interest | |
207 | * | |
208 | * This function will match the cooling level corresponding to the | |
209 | * requested @freq and return it. | |
210 | * | |
211 | * Return: The matched cooling level on success or THERMAL_CSTATE_INVALID | |
212 | * otherwise. | |
213 | */ | |
214 | unsigned long clock_cooling_get_level(struct thermal_cooling_device *cdev, | |
215 | unsigned long freq) | |
216 | { | |
217 | struct clock_cooling_device *ccdev = cdev->devdata; | |
218 | unsigned long val; | |
219 | ||
220 | if (clock_cooling_get_property(ccdev, (unsigned long)freq, &val, | |
221 | GET_LEVEL)) | |
222 | return THERMAL_CSTATE_INVALID; | |
223 | ||
224 | return val; | |
225 | } | |
226 | EXPORT_SYMBOL_GPL(clock_cooling_get_level); | |
227 | ||
228 | /** | |
229 | * clock_cooling_get_frequency - get the absolute value of frequency from level. | |
230 | * @ccdev: clock cooling device reference | |
231 | * @level: cooling level | |
232 | * | |
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 | |
237 | * | |
238 | * Return: 0 on error, the corresponding frequency otherwise. | |
239 | */ | |
240 | static unsigned long | |
241 | clock_cooling_get_frequency(struct clock_cooling_device *ccdev, | |
242 | unsigned long level) | |
243 | { | |
244 | int ret = 0; | |
245 | unsigned long freq; | |
246 | ||
247 | ret = clock_cooling_get_property(ccdev, level, &freq, GET_FREQ); | |
248 | if (ret) | |
249 | return 0; | |
250 | ||
251 | return freq; | |
252 | } | |
253 | ||
254 | /** | |
255 | * clock_cooling_apply - function to apply frequency clipping. | |
256 | * @ccdev: clock_cooling_device pointer containing frequency clipping data. | |
257 | * @cooling_state: value of the cooling state. | |
258 | * | |
259 | * Function used to make sure the clock layer is aware of current thermal | |
260 | * limits. The limits are applied by updating the clock rate in case it is | |
261 | * higher than the corresponding frequency based on the requested cooling_state. | |
262 | * | |
263 | * Return: 0 on success, an error code otherwise (-EINVAL in case wrong | |
264 | * cooling state). | |
265 | */ | |
266 | static int clock_cooling_apply(struct clock_cooling_device *ccdev, | |
267 | unsigned long cooling_state) | |
268 | { | |
269 | unsigned long clip_freq, cur_freq; | |
270 | int ret = 0; | |
271 | ||
272 | /* Here we write the clipping */ | |
273 | /* Check if the old cooling action is same as new cooling action */ | |
274 | if (ccdev->clock_state == cooling_state) | |
275 | return 0; | |
276 | ||
277 | clip_freq = clock_cooling_get_frequency(ccdev, cooling_state); | |
278 | if (!clip_freq) | |
279 | return -EINVAL; | |
280 | ||
281 | cur_freq = clk_get_rate(ccdev->clk); | |
282 | ||
283 | mutex_lock(&ccdev->lock); | |
284 | ccdev->clock_state = cooling_state; | |
285 | ccdev->clock_val = clip_freq; | |
286 | /* enforce clock level */ | |
287 | if (cur_freq > clip_freq) | |
288 | ret = clk_set_rate(ccdev->clk, clip_freq); | |
289 | mutex_unlock(&ccdev->lock); | |
290 | ||
291 | return ret; | |
292 | } | |
293 | ||
294 | /** | |
295 | * clock_cooling_clock_notifier - notifier callback on clock rate changes. | |
296 | * @nb: struct notifier_block * with callback info. | |
297 | * @event: value showing clock event for which this function invoked. | |
298 | * @data: callback-specific data | |
299 | * | |
300 | * Callback to hijack the notification on clock transition. | |
301 | * Every time there is a clock change, we intercept all pre change events | |
302 | * and block the transition in case the new rate infringes thermal limits. | |
303 | * | |
304 | * Return: NOTIFY_DONE (success) or NOTIFY_BAD (new_rate > thermal limit). | |
305 | */ | |
306 | static int clock_cooling_clock_notifier(struct notifier_block *nb, | |
307 | unsigned long event, void *data) | |
308 | { | |
309 | struct clk_notifier_data *ndata = data; | |
310 | struct clock_cooling_device *ccdev = to_clock_cooling_device(nb); | |
311 | ||
312 | switch (event) { | |
313 | case PRE_RATE_CHANGE: | |
314 | /* | |
315 | * checks on current state | |
316 | * TODO: current method is not best we can find as it | |
317 | * allows possibly voltage transitions, in case DVFS | |
318 | * layer is also hijacking clock pre notifications. | |
319 | */ | |
320 | if (ndata->new_rate > ccdev->clock_val) | |
321 | return NOTIFY_BAD; | |
322 | /* fall through */ | |
323 | case POST_RATE_CHANGE: | |
324 | case ABORT_RATE_CHANGE: | |
325 | default: | |
326 | return NOTIFY_DONE; | |
327 | } | |
328 | } | |
329 | ||
330 | /* clock cooling device thermal callback functions are defined below */ | |
331 | ||
332 | /** | |
333 | * clock_cooling_get_max_state - callback function to get the max cooling state. | |
334 | * @cdev: thermal cooling device pointer. | |
335 | * @state: fill this variable with the max cooling state. | |
336 | * | |
337 | * Callback for the thermal cooling device to return the clock | |
338 | * max cooling state. | |
339 | * | |
340 | * Return: 0 on success, an error code otherwise. | |
341 | */ | |
342 | static int clock_cooling_get_max_state(struct thermal_cooling_device *cdev, | |
343 | unsigned long *state) | |
344 | { | |
345 | struct clock_cooling_device *ccdev = cdev->devdata; | |
346 | unsigned long count = 0; | |
347 | int ret; | |
348 | ||
349 | ret = clock_cooling_get_property(ccdev, 0, &count, GET_MAXL); | |
350 | if (!ret) | |
351 | *state = count; | |
352 | ||
353 | return ret; | |
354 | } | |
355 | ||
356 | /** | |
357 | * clock_cooling_get_cur_state - function to get the current cooling state. | |
358 | * @cdev: thermal cooling device pointer. | |
359 | * @state: fill this variable with the current cooling state. | |
360 | * | |
361 | * Callback for the thermal cooling device to return the clock | |
362 | * current cooling state. | |
363 | * | |
364 | * Return: 0 (success) | |
365 | */ | |
366 | static int clock_cooling_get_cur_state(struct thermal_cooling_device *cdev, | |
367 | unsigned long *state) | |
368 | { | |
369 | struct clock_cooling_device *ccdev = cdev->devdata; | |
370 | ||
371 | *state = ccdev->clock_state; | |
372 | ||
373 | return 0; | |
374 | } | |
375 | ||
376 | /** | |
377 | * clock_cooling_set_cur_state - function to set the current cooling state. | |
378 | * @cdev: thermal cooling device pointer. | |
379 | * @state: set this variable to the current cooling state. | |
380 | * | |
381 | * Callback for the thermal cooling device to change the clock cooling | |
382 | * current cooling state. | |
383 | * | |
384 | * Return: 0 on success, an error code otherwise. | |
385 | */ | |
386 | static int clock_cooling_set_cur_state(struct thermal_cooling_device *cdev, | |
387 | unsigned long state) | |
388 | { | |
389 | struct clock_cooling_device *clock_device = cdev->devdata; | |
390 | ||
391 | return clock_cooling_apply(clock_device, state); | |
392 | } | |
393 | ||
394 | /* Bind clock callbacks to thermal cooling device ops */ | |
395 | static struct thermal_cooling_device_ops const clock_cooling_ops = { | |
396 | .get_max_state = clock_cooling_get_max_state, | |
397 | .get_cur_state = clock_cooling_get_cur_state, | |
398 | .set_cur_state = clock_cooling_set_cur_state, | |
399 | }; | |
400 | ||
401 | /** | |
402 | * clock_cooling_register - function to create clock cooling device. | |
403 | * @dev: struct device pointer to the device used as clock cooling device. | |
404 | * @clock_name: string containing the clock used as cooling mechanism. | |
405 | * | |
406 | * This interface function registers the clock cooling device with the name | |
407 | * "thermal-clock-%x". The cooling device is based on clock frequencies. | |
408 | * The struct device is assumed to be capable of DVFS transitions. | |
409 | * The OPP layer is used to fetch and fill the available frequencies for | |
410 | * the referred device. The ordered frequency table is used to control | |
411 | * the clock cooling device cooling states and to limit clock transitions | |
412 | * based on the cooling state requested by the thermal framework. | |
413 | * | |
414 | * Return: a valid struct thermal_cooling_device pointer on success, | |
415 | * on failure, it returns a corresponding ERR_PTR(). | |
416 | */ | |
417 | struct thermal_cooling_device * | |
418 | clock_cooling_register(struct device *dev, const char *clock_name) | |
419 | { | |
420 | struct thermal_cooling_device *cdev; | |
421 | struct clock_cooling_device *ccdev = NULL; | |
422 | char dev_name[THERMAL_NAME_LENGTH]; | |
423 | int ret = 0; | |
424 | ||
425 | ccdev = devm_kzalloc(dev, sizeof(*ccdev), GFP_KERNEL); | |
426 | if (!ccdev) | |
427 | return ERR_PTR(-ENOMEM); | |
428 | ||
165989a5 | 429 | mutex_init(&ccdev->lock); |
f9df89d8 EV |
430 | ccdev->dev = dev; |
431 | ccdev->clk = devm_clk_get(dev, clock_name); | |
432 | if (IS_ERR(ccdev->clk)) | |
433 | return ERR_CAST(ccdev->clk); | |
434 | ||
435 | ret = clock_cooling_get_idr(&ccdev->id); | |
436 | if (ret) | |
437 | return ERR_PTR(-EINVAL); | |
438 | ||
439 | snprintf(dev_name, sizeof(dev_name), "thermal-clock-%d", ccdev->id); | |
440 | ||
441 | cdev = thermal_cooling_device_register(dev_name, ccdev, | |
442 | &clock_cooling_ops); | |
443 | if (IS_ERR(cdev)) { | |
444 | release_idr(ccdev->id); | |
445 | return ERR_PTR(-EINVAL); | |
446 | } | |
447 | ccdev->cdev = cdev; | |
448 | ccdev->clk_rate_change_nb.notifier_call = clock_cooling_clock_notifier; | |
449 | ||
450 | /* Assuming someone has already filled the opp table for this device */ | |
451 | ret = dev_pm_opp_init_cpufreq_table(dev, &ccdev->freq_table); | |
452 | if (ret) { | |
453 | release_idr(ccdev->id); | |
454 | return ERR_PTR(ret); | |
455 | } | |
456 | ccdev->clock_state = 0; | |
457 | ccdev->clock_val = clock_cooling_get_frequency(ccdev, 0); | |
458 | ||
459 | clk_notifier_register(ccdev->clk, &ccdev->clk_rate_change_nb); | |
460 | ||
461 | return cdev; | |
462 | } | |
463 | EXPORT_SYMBOL_GPL(clock_cooling_register); | |
464 | ||
465 | /** | |
466 | * clock_cooling_unregister - function to remove clock cooling device. | |
467 | * @cdev: thermal cooling device pointer. | |
468 | * | |
469 | * This interface function unregisters the "thermal-clock-%x" cooling device. | |
470 | */ | |
471 | void clock_cooling_unregister(struct thermal_cooling_device *cdev) | |
472 | { | |
473 | struct clock_cooling_device *ccdev; | |
474 | ||
475 | if (!cdev) | |
476 | return; | |
477 | ||
478 | ccdev = cdev->devdata; | |
479 | ||
480 | clk_notifier_unregister(ccdev->clk, &ccdev->clk_rate_change_nb); | |
481 | dev_pm_opp_free_cpufreq_table(ccdev->dev, &ccdev->freq_table); | |
482 | ||
483 | thermal_cooling_device_unregister(ccdev->cdev); | |
484 | release_idr(ccdev->id); | |
485 | } | |
486 | EXPORT_SYMBOL_GPL(clock_cooling_unregister); |