Eduardo Valentin | f9df89d | 2014-01-06 09:04:18 -0400 | [diff] [blame] | 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 | |
Wei Yongjun | 165989a | 2016-07-25 07:01:19 +0000 | [diff] [blame] | 429 | mutex_init(&ccdev->lock); |
Eduardo Valentin | f9df89d | 2014-01-06 09:04:18 -0400 | [diff] [blame] | 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); |