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8e8e69d6 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
f9df89d8 EV |
2 | /* |
3 | * drivers/thermal/clock_cooling.c | |
4 | * | |
5 | * Copyright (C) 2014 Eduardo Valentin <edubezval@gmail.com> | |
6 | * | |
7 | * Copyright (C) 2013 Texas Instruments Inc. | |
8 | * Contact: Eduardo Valentin <eduardo.valentin@ti.com> | |
9 | * | |
10 | * Highly based on cpu_cooling.c. | |
11 | * Copyright (C) 2012 Samsung Electronics Co., Ltd(http://www.samsung.com) | |
12 | * Copyright (C) 2012 Amit Daniel <amit.kachhap@linaro.org> | |
f9df89d8 EV |
13 | */ |
14 | #include <linux/clk.h> | |
15 | #include <linux/cpufreq.h> | |
16 | #include <linux/device.h> | |
17 | #include <linux/err.h> | |
18 | #include <linux/idr.h> | |
19 | #include <linux/mutex.h> | |
20 | #include <linux/pm_opp.h> | |
21 | #include <linux/slab.h> | |
22 | #include <linux/thermal.h> | |
23 | #include <linux/clock_cooling.h> | |
24 | ||
25 | /** | |
26 | * struct clock_cooling_device - data for cooling device with clock | |
27 | * @id: unique integer value corresponding to each clock_cooling_device | |
28 | * registered. | |
29 | * @dev: struct device pointer to the device being used to cool off using | |
30 | * clock frequencies. | |
31 | * @cdev: thermal_cooling_device pointer to keep track of the | |
32 | * registered cooling device. | |
33 | * @clk_rate_change_nb: reference to notifier block used to receive clock | |
34 | * rate changes. | |
35 | * @freq_table: frequency table used to keep track of available frequencies. | |
36 | * @clock_state: integer value representing the current state of clock | |
37 | * cooling devices. | |
38 | * @clock_val: integer value representing the absolute value of the clipped | |
39 | * frequency. | |
40 | * @clk: struct clk reference used to enforce clock limits. | |
41 | * @lock: mutex lock to protect this struct. | |
42 | * | |
43 | * This structure is required for keeping information of each | |
44 | * clock_cooling_device registered. In order to prevent corruption of this a | |
45 | * mutex @lock is used. | |
46 | */ | |
47 | struct clock_cooling_device { | |
48 | int id; | |
49 | struct device *dev; | |
50 | struct thermal_cooling_device *cdev; | |
51 | struct notifier_block clk_rate_change_nb; | |
52 | struct cpufreq_frequency_table *freq_table; | |
53 | unsigned long clock_state; | |
54 | unsigned long clock_val; | |
55 | struct clk *clk; | |
56 | struct mutex lock; /* lock to protect the content of this struct */ | |
57 | }; | |
58 | #define to_clock_cooling_device(x) \ | |
59 | container_of(x, struct clock_cooling_device, clk_rate_change_nb) | |
7a6639dc | 60 | static DEFINE_IDA(clock_ida); |
f9df89d8 EV |
61 | |
62 | /* Below code defines functions to be used for clock as cooling device */ | |
63 | ||
64 | enum clock_cooling_property { | |
65 | GET_LEVEL, | |
66 | GET_FREQ, | |
67 | GET_MAXL, | |
68 | }; | |
69 | ||
70 | /** | |
71 | * clock_cooling_get_property - fetch a property of interest for a give cpu. | |
72 | * @ccdev: clock cooling device reference | |
73 | * @input: query parameter | |
74 | * @output: query return | |
75 | * @property: type of query (frequency, level, max level) | |
76 | * | |
77 | * This is the common function to | |
78 | * 1. get maximum clock cooling states | |
79 | * 2. translate frequency to cooling state | |
80 | * 3. translate cooling state to frequency | |
81 | * Note that the code may be not in good shape | |
82 | * but it is written in this way in order to: | |
83 | * a) reduce duplicate code as most of the code can be shared. | |
84 | * b) make sure the logic is consistent when translating between | |
85 | * cooling states and frequencies. | |
86 | * | |
87 | * Return: 0 on success, -EINVAL when invalid parameters are passed. | |
88 | */ | |
89 | static int clock_cooling_get_property(struct clock_cooling_device *ccdev, | |
90 | unsigned long input, | |
91 | unsigned long *output, | |
92 | enum clock_cooling_property property) | |
93 | { | |
94 | int i; | |
95 | unsigned long max_level = 0, level = 0; | |
96 | unsigned int freq = CPUFREQ_ENTRY_INVALID; | |
97 | int descend = -1; | |
98 | struct cpufreq_frequency_table *pos, *table = ccdev->freq_table; | |
99 | ||
100 | if (!output) | |
101 | return -EINVAL; | |
102 | ||
103 | if (!table) | |
104 | return -EINVAL; | |
105 | ||
106 | cpufreq_for_each_valid_entry(pos, table) { | |
107 | /* ignore duplicate entry */ | |
108 | if (freq == pos->frequency) | |
109 | continue; | |
110 | ||
111 | /* get the frequency order */ | |
112 | if (freq != CPUFREQ_ENTRY_INVALID && descend == -1) | |
113 | descend = freq > pos->frequency; | |
114 | ||
115 | freq = pos->frequency; | |
116 | max_level++; | |
117 | } | |
118 | ||
119 | /* No valid cpu frequency entry */ | |
120 | if (max_level == 0) | |
121 | return -EINVAL; | |
122 | ||
123 | /* max_level is an index, not a counter */ | |
124 | max_level--; | |
125 | ||
126 | /* get max level */ | |
127 | if (property == GET_MAXL) { | |
128 | *output = max_level; | |
129 | return 0; | |
130 | } | |
131 | ||
132 | if (property == GET_FREQ) | |
133 | level = descend ? input : (max_level - input); | |
134 | ||
135 | i = 0; | |
136 | cpufreq_for_each_valid_entry(pos, table) { | |
137 | /* ignore duplicate entry */ | |
138 | if (freq == pos->frequency) | |
139 | continue; | |
140 | ||
141 | /* now we have a valid frequency entry */ | |
142 | freq = pos->frequency; | |
143 | ||
144 | if (property == GET_LEVEL && (unsigned int)input == freq) { | |
145 | /* get level by frequency */ | |
146 | *output = descend ? i : (max_level - i); | |
147 | return 0; | |
148 | } | |
149 | if (property == GET_FREQ && level == i) { | |
150 | /* get frequency by level */ | |
151 | *output = freq; | |
152 | return 0; | |
153 | } | |
154 | i++; | |
155 | } | |
156 | ||
157 | return -EINVAL; | |
158 | } | |
159 | ||
160 | /** | |
161 | * clock_cooling_get_level - return the cooling level of given clock cooling. | |
162 | * @cdev: reference of a thermal cooling device of used as clock cooling device | |
163 | * @freq: the frequency of interest | |
164 | * | |
165 | * This function will match the cooling level corresponding to the | |
166 | * requested @freq and return it. | |
167 | * | |
168 | * Return: The matched cooling level on success or THERMAL_CSTATE_INVALID | |
169 | * otherwise. | |
170 | */ | |
171 | unsigned long clock_cooling_get_level(struct thermal_cooling_device *cdev, | |
172 | unsigned long freq) | |
173 | { | |
174 | struct clock_cooling_device *ccdev = cdev->devdata; | |
175 | unsigned long val; | |
176 | ||
177 | if (clock_cooling_get_property(ccdev, (unsigned long)freq, &val, | |
178 | GET_LEVEL)) | |
179 | return THERMAL_CSTATE_INVALID; | |
180 | ||
181 | return val; | |
182 | } | |
183 | EXPORT_SYMBOL_GPL(clock_cooling_get_level); | |
184 | ||
185 | /** | |
186 | * clock_cooling_get_frequency - get the absolute value of frequency from level. | |
187 | * @ccdev: clock cooling device reference | |
188 | * @level: cooling level | |
189 | * | |
190 | * This function matches cooling level with frequency. Based on a cooling level | |
191 | * of frequency, equals cooling state of cpu cooling device, it will return | |
192 | * the corresponding frequency. | |
193 | * e.g level=0 --> 1st MAX FREQ, level=1 ---> 2nd MAX FREQ, .... etc | |
194 | * | |
195 | * Return: 0 on error, the corresponding frequency otherwise. | |
196 | */ | |
197 | static unsigned long | |
198 | clock_cooling_get_frequency(struct clock_cooling_device *ccdev, | |
199 | unsigned long level) | |
200 | { | |
201 | int ret = 0; | |
202 | unsigned long freq; | |
203 | ||
204 | ret = clock_cooling_get_property(ccdev, level, &freq, GET_FREQ); | |
205 | if (ret) | |
206 | return 0; | |
207 | ||
208 | return freq; | |
209 | } | |
210 | ||
211 | /** | |
212 | * clock_cooling_apply - function to apply frequency clipping. | |
213 | * @ccdev: clock_cooling_device pointer containing frequency clipping data. | |
214 | * @cooling_state: value of the cooling state. | |
215 | * | |
216 | * Function used to make sure the clock layer is aware of current thermal | |
217 | * limits. The limits are applied by updating the clock rate in case it is | |
218 | * higher than the corresponding frequency based on the requested cooling_state. | |
219 | * | |
220 | * Return: 0 on success, an error code otherwise (-EINVAL in case wrong | |
221 | * cooling state). | |
222 | */ | |
223 | static int clock_cooling_apply(struct clock_cooling_device *ccdev, | |
224 | unsigned long cooling_state) | |
225 | { | |
226 | unsigned long clip_freq, cur_freq; | |
227 | int ret = 0; | |
228 | ||
229 | /* Here we write the clipping */ | |
230 | /* Check if the old cooling action is same as new cooling action */ | |
231 | if (ccdev->clock_state == cooling_state) | |
232 | return 0; | |
233 | ||
234 | clip_freq = clock_cooling_get_frequency(ccdev, cooling_state); | |
235 | if (!clip_freq) | |
236 | return -EINVAL; | |
237 | ||
238 | cur_freq = clk_get_rate(ccdev->clk); | |
239 | ||
240 | mutex_lock(&ccdev->lock); | |
241 | ccdev->clock_state = cooling_state; | |
242 | ccdev->clock_val = clip_freq; | |
243 | /* enforce clock level */ | |
244 | if (cur_freq > clip_freq) | |
245 | ret = clk_set_rate(ccdev->clk, clip_freq); | |
246 | mutex_unlock(&ccdev->lock); | |
247 | ||
248 | return ret; | |
249 | } | |
250 | ||
251 | /** | |
252 | * clock_cooling_clock_notifier - notifier callback on clock rate changes. | |
253 | * @nb: struct notifier_block * with callback info. | |
254 | * @event: value showing clock event for which this function invoked. | |
255 | * @data: callback-specific data | |
256 | * | |
257 | * Callback to hijack the notification on clock transition. | |
258 | * Every time there is a clock change, we intercept all pre change events | |
259 | * and block the transition in case the new rate infringes thermal limits. | |
260 | * | |
261 | * Return: NOTIFY_DONE (success) or NOTIFY_BAD (new_rate > thermal limit). | |
262 | */ | |
263 | static int clock_cooling_clock_notifier(struct notifier_block *nb, | |
264 | unsigned long event, void *data) | |
265 | { | |
266 | struct clk_notifier_data *ndata = data; | |
267 | struct clock_cooling_device *ccdev = to_clock_cooling_device(nb); | |
268 | ||
269 | switch (event) { | |
270 | case PRE_RATE_CHANGE: | |
271 | /* | |
272 | * checks on current state | |
273 | * TODO: current method is not best we can find as it | |
274 | * allows possibly voltage transitions, in case DVFS | |
275 | * layer is also hijacking clock pre notifications. | |
276 | */ | |
277 | if (ndata->new_rate > ccdev->clock_val) | |
278 | return NOTIFY_BAD; | |
279 | /* fall through */ | |
280 | case POST_RATE_CHANGE: | |
281 | case ABORT_RATE_CHANGE: | |
282 | default: | |
283 | return NOTIFY_DONE; | |
284 | } | |
285 | } | |
286 | ||
287 | /* clock cooling device thermal callback functions are defined below */ | |
288 | ||
289 | /** | |
290 | * clock_cooling_get_max_state - callback function to get the max cooling state. | |
291 | * @cdev: thermal cooling device pointer. | |
292 | * @state: fill this variable with the max cooling state. | |
293 | * | |
294 | * Callback for the thermal cooling device to return the clock | |
295 | * max cooling state. | |
296 | * | |
297 | * Return: 0 on success, an error code otherwise. | |
298 | */ | |
299 | static int clock_cooling_get_max_state(struct thermal_cooling_device *cdev, | |
300 | unsigned long *state) | |
301 | { | |
302 | struct clock_cooling_device *ccdev = cdev->devdata; | |
303 | unsigned long count = 0; | |
304 | int ret; | |
305 | ||
306 | ret = clock_cooling_get_property(ccdev, 0, &count, GET_MAXL); | |
307 | if (!ret) | |
308 | *state = count; | |
309 | ||
310 | return ret; | |
311 | } | |
312 | ||
313 | /** | |
314 | * clock_cooling_get_cur_state - function to get the current cooling state. | |
315 | * @cdev: thermal cooling device pointer. | |
316 | * @state: fill this variable with the current cooling state. | |
317 | * | |
318 | * Callback for the thermal cooling device to return the clock | |
319 | * current cooling state. | |
320 | * | |
321 | * Return: 0 (success) | |
322 | */ | |
323 | static int clock_cooling_get_cur_state(struct thermal_cooling_device *cdev, | |
324 | unsigned long *state) | |
325 | { | |
326 | struct clock_cooling_device *ccdev = cdev->devdata; | |
327 | ||
328 | *state = ccdev->clock_state; | |
329 | ||
330 | return 0; | |
331 | } | |
332 | ||
333 | /** | |
334 | * clock_cooling_set_cur_state - function to set the current cooling state. | |
335 | * @cdev: thermal cooling device pointer. | |
336 | * @state: set this variable to the current cooling state. | |
337 | * | |
338 | * Callback for the thermal cooling device to change the clock cooling | |
339 | * current cooling state. | |
340 | * | |
341 | * Return: 0 on success, an error code otherwise. | |
342 | */ | |
343 | static int clock_cooling_set_cur_state(struct thermal_cooling_device *cdev, | |
344 | unsigned long state) | |
345 | { | |
346 | struct clock_cooling_device *clock_device = cdev->devdata; | |
347 | ||
348 | return clock_cooling_apply(clock_device, state); | |
349 | } | |
350 | ||
351 | /* Bind clock callbacks to thermal cooling device ops */ | |
352 | static struct thermal_cooling_device_ops const clock_cooling_ops = { | |
353 | .get_max_state = clock_cooling_get_max_state, | |
354 | .get_cur_state = clock_cooling_get_cur_state, | |
355 | .set_cur_state = clock_cooling_set_cur_state, | |
356 | }; | |
357 | ||
358 | /** | |
359 | * clock_cooling_register - function to create clock cooling device. | |
360 | * @dev: struct device pointer to the device used as clock cooling device. | |
361 | * @clock_name: string containing the clock used as cooling mechanism. | |
362 | * | |
363 | * This interface function registers the clock cooling device with the name | |
364 | * "thermal-clock-%x". The cooling device is based on clock frequencies. | |
365 | * The struct device is assumed to be capable of DVFS transitions. | |
366 | * The OPP layer is used to fetch and fill the available frequencies for | |
367 | * the referred device. The ordered frequency table is used to control | |
368 | * the clock cooling device cooling states and to limit clock transitions | |
369 | * based on the cooling state requested by the thermal framework. | |
370 | * | |
371 | * Return: a valid struct thermal_cooling_device pointer on success, | |
372 | * on failure, it returns a corresponding ERR_PTR(). | |
373 | */ | |
374 | struct thermal_cooling_device * | |
375 | clock_cooling_register(struct device *dev, const char *clock_name) | |
376 | { | |
377 | struct thermal_cooling_device *cdev; | |
378 | struct clock_cooling_device *ccdev = NULL; | |
379 | char dev_name[THERMAL_NAME_LENGTH]; | |
380 | int ret = 0; | |
381 | ||
382 | ccdev = devm_kzalloc(dev, sizeof(*ccdev), GFP_KERNEL); | |
383 | if (!ccdev) | |
384 | return ERR_PTR(-ENOMEM); | |
385 | ||
165989a5 | 386 | mutex_init(&ccdev->lock); |
f9df89d8 EV |
387 | ccdev->dev = dev; |
388 | ccdev->clk = devm_clk_get(dev, clock_name); | |
389 | if (IS_ERR(ccdev->clk)) | |
390 | return ERR_CAST(ccdev->clk); | |
391 | ||
7a6639dc MW |
392 | ret = ida_simple_get(&clock_ida, 0, 0, GFP_KERNEL); |
393 | if (ret < 0) | |
394 | return ERR_PTR(ret); | |
395 | ccdev->id = ret; | |
f9df89d8 EV |
396 | |
397 | snprintf(dev_name, sizeof(dev_name), "thermal-clock-%d", ccdev->id); | |
398 | ||
399 | cdev = thermal_cooling_device_register(dev_name, ccdev, | |
400 | &clock_cooling_ops); | |
401 | if (IS_ERR(cdev)) { | |
7a6639dc | 402 | ida_simple_remove(&clock_ida, ccdev->id); |
f9df89d8 EV |
403 | return ERR_PTR(-EINVAL); |
404 | } | |
405 | ccdev->cdev = cdev; | |
406 | ccdev->clk_rate_change_nb.notifier_call = clock_cooling_clock_notifier; | |
407 | ||
408 | /* Assuming someone has already filled the opp table for this device */ | |
409 | ret = dev_pm_opp_init_cpufreq_table(dev, &ccdev->freq_table); | |
410 | if (ret) { | |
7a6639dc | 411 | ida_simple_remove(&clock_ida, ccdev->id); |
f9df89d8 EV |
412 | return ERR_PTR(ret); |
413 | } | |
414 | ccdev->clock_state = 0; | |
415 | ccdev->clock_val = clock_cooling_get_frequency(ccdev, 0); | |
416 | ||
417 | clk_notifier_register(ccdev->clk, &ccdev->clk_rate_change_nb); | |
418 | ||
419 | return cdev; | |
420 | } | |
421 | EXPORT_SYMBOL_GPL(clock_cooling_register); | |
422 | ||
423 | /** | |
424 | * clock_cooling_unregister - function to remove clock cooling device. | |
425 | * @cdev: thermal cooling device pointer. | |
426 | * | |
427 | * This interface function unregisters the "thermal-clock-%x" cooling device. | |
428 | */ | |
429 | void clock_cooling_unregister(struct thermal_cooling_device *cdev) | |
430 | { | |
431 | struct clock_cooling_device *ccdev; | |
432 | ||
433 | if (!cdev) | |
434 | return; | |
435 | ||
436 | ccdev = cdev->devdata; | |
437 | ||
438 | clk_notifier_unregister(ccdev->clk, &ccdev->clk_rate_change_nb); | |
439 | dev_pm_opp_free_cpufreq_table(ccdev->dev, &ccdev->freq_table); | |
440 | ||
441 | thermal_cooling_device_unregister(ccdev->cdev); | |
7a6639dc | 442 | ida_simple_remove(&clock_ida, ccdev->id); |
f9df89d8 EV |
443 | } |
444 | EXPORT_SYMBOL_GPL(clock_cooling_unregister); |