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Diffstat (limited to 'kernel/drivers/thermal/clock_cooling.c')
| -rw-r--r-- | kernel/drivers/thermal/clock_cooling.c | 485 |
1 files changed, 485 insertions, 0 deletions
diff --git a/kernel/drivers/thermal/clock_cooling.c b/kernel/drivers/thermal/clock_cooling.c new file mode 100644 index 000000000..1b4ff0f4c --- /dev/null +++ b/kernel/drivers/thermal/clock_cooling.c @@ -0,0 +1,485 @@ +/* + * drivers/thermal/clock_cooling.c + * + * Copyright (C) 2014 Eduardo Valentin <edubezval@gmail.com> + * + * Copyright (C) 2013 Texas Instruments Inc. + * Contact: Eduardo Valentin <eduardo.valentin@ti.com> + * + * Highly based on cpu_cooling.c. + * Copyright (C) 2012 Samsung Electronics Co., Ltd(http://www.samsung.com) + * Copyright (C) 2012 Amit Daniel <amit.kachhap@linaro.org> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; version 2 of the License. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + */ +#include <linux/clk.h> +#include <linux/cpufreq.h> +#include <linux/device.h> +#include <linux/err.h> +#include <linux/idr.h> +#include <linux/mutex.h> +#include <linux/pm_opp.h> +#include <linux/slab.h> +#include <linux/thermal.h> +#include <linux/clock_cooling.h> + +/** + * struct clock_cooling_device - data for cooling device with clock + * @id: unique integer value corresponding to each clock_cooling_device + * registered. + * @dev: struct device pointer to the device being used to cool off using + * clock frequencies. + * @cdev: thermal_cooling_device pointer to keep track of the + * registered cooling device. + * @clk_rate_change_nb: reference to notifier block used to receive clock + * rate changes. + * @freq_table: frequency table used to keep track of available frequencies. + * @clock_state: integer value representing the current state of clock + * cooling devices. + * @clock_val: integer value representing the absolute value of the clipped + * frequency. + * @clk: struct clk reference used to enforce clock limits. + * @lock: mutex lock to protect this struct. + * + * This structure is required for keeping information of each + * clock_cooling_device registered. In order to prevent corruption of this a + * mutex @lock is used. + */ +struct clock_cooling_device { + int id; + struct device *dev; + struct thermal_cooling_device *cdev; + struct notifier_block clk_rate_change_nb; + struct cpufreq_frequency_table *freq_table; + unsigned long clock_state; + unsigned long clock_val; + struct clk *clk; + struct mutex lock; /* lock to protect the content of this struct */ +}; +#define to_clock_cooling_device(x) \ + container_of(x, struct clock_cooling_device, clk_rate_change_nb) +static DEFINE_IDR(clock_idr); +static DEFINE_MUTEX(cooling_clock_lock); + +/** + * clock_cooling_get_idr - function to get an unique id. + * @id: int * value generated by this function. + * + * This function will populate @id with an unique + * id, using the idr API. + * + * Return: 0 on success, an error code on failure. + */ +static int clock_cooling_get_idr(int *id) +{ + int ret; + + mutex_lock(&cooling_clock_lock); + ret = idr_alloc(&clock_idr, NULL, 0, 0, GFP_KERNEL); + mutex_unlock(&cooling_clock_lock); + if (unlikely(ret < 0)) + return ret; + *id = ret; + + return 0; +} + +/** + * release_idr - function to free the unique id. + * @id: int value representing the unique id. + */ +static void release_idr(int id) +{ + mutex_lock(&cooling_clock_lock); + idr_remove(&clock_idr, id); + mutex_unlock(&cooling_clock_lock); +} + +/* Below code defines functions to be used for clock as cooling device */ + +enum clock_cooling_property { + GET_LEVEL, + GET_FREQ, + GET_MAXL, +}; + +/** + * clock_cooling_get_property - fetch a property of interest for a give cpu. + * @ccdev: clock cooling device reference + * @input: query parameter + * @output: query return + * @property: type of query (frequency, level, max level) + * + * This is the common function to + * 1. get maximum clock cooling states + * 2. translate frequency to cooling state + * 3. translate cooling state to frequency + * Note that the code may be not in good shape + * but it is written in this way in order to: + * a) reduce duplicate code as most of the code can be shared. + * b) make sure the logic is consistent when translating between + * cooling states and frequencies. + * + * Return: 0 on success, -EINVAL when invalid parameters are passed. + */ +static int clock_cooling_get_property(struct clock_cooling_device *ccdev, + unsigned long input, + unsigned long *output, + enum clock_cooling_property property) +{ + int i; + unsigned long max_level = 0, level = 0; + unsigned int freq = CPUFREQ_ENTRY_INVALID; + int descend = -1; + struct cpufreq_frequency_table *pos, *table = ccdev->freq_table; + + if (!output) + return -EINVAL; + + if (!table) + return -EINVAL; + + cpufreq_for_each_valid_entry(pos, table) { + /* ignore duplicate entry */ + if (freq == pos->frequency) + continue; + + /* get the frequency order */ + if (freq != CPUFREQ_ENTRY_INVALID && descend == -1) + descend = freq > pos->frequency; + + freq = pos->frequency; + max_level++; + } + + /* No valid cpu frequency entry */ + if (max_level == 0) + return -EINVAL; + + /* max_level is an index, not a counter */ + max_level--; + + /* get max level */ + if (property == GET_MAXL) { + *output = max_level; + return 0; + } + + if (property == GET_FREQ) + level = descend ? input : (max_level - input); + + i = 0; + cpufreq_for_each_valid_entry(pos, table) { + /* ignore duplicate entry */ + if (freq == pos->frequency) + continue; + + /* now we have a valid frequency entry */ + freq = pos->frequency; + + if (property == GET_LEVEL && (unsigned int)input == freq) { + /* get level by frequency */ + *output = descend ? i : (max_level - i); + return 0; + } + if (property == GET_FREQ && level == i) { + /* get frequency by level */ + *output = freq; + return 0; + } + i++; + } + + return -EINVAL; +} + +/** + * clock_cooling_get_level - return the cooling level of given clock cooling. + * @cdev: reference of a thermal cooling device of used as clock cooling device + * @freq: the frequency of interest + * + * This function will match the cooling level corresponding to the + * requested @freq and return it. + * + * Return: The matched cooling level on success or THERMAL_CSTATE_INVALID + * otherwise. + */ +unsigned long clock_cooling_get_level(struct thermal_cooling_device *cdev, + unsigned long freq) +{ + struct clock_cooling_device *ccdev = cdev->devdata; + unsigned long val; + + if (clock_cooling_get_property(ccdev, (unsigned long)freq, &val, + GET_LEVEL)) + return THERMAL_CSTATE_INVALID; + + return val; +} +EXPORT_SYMBOL_GPL(clock_cooling_get_level); + +/** + * clock_cooling_get_frequency - get the absolute value of frequency from level. + * @ccdev: clock cooling device reference + * @level: cooling level + * + * This function matches cooling level with frequency. Based on a cooling level + * of frequency, equals cooling state of cpu cooling device, it will return + * the corresponding frequency. + * e.g level=0 --> 1st MAX FREQ, level=1 ---> 2nd MAX FREQ, .... etc + * + * Return: 0 on error, the corresponding frequency otherwise. + */ +static unsigned long +clock_cooling_get_frequency(struct clock_cooling_device *ccdev, + unsigned long level) +{ + int ret = 0; + unsigned long freq; + + ret = clock_cooling_get_property(ccdev, level, &freq, GET_FREQ); + if (ret) + return 0; + + return freq; +} + +/** + * clock_cooling_apply - function to apply frequency clipping. + * @ccdev: clock_cooling_device pointer containing frequency clipping data. + * @cooling_state: value of the cooling state. + * + * Function used to make sure the clock layer is aware of current thermal + * limits. The limits are applied by updating the clock rate in case it is + * higher than the corresponding frequency based on the requested cooling_state. + * + * Return: 0 on success, an error code otherwise (-EINVAL in case wrong + * cooling state). + */ +static int clock_cooling_apply(struct clock_cooling_device *ccdev, + unsigned long cooling_state) +{ + unsigned long clip_freq, cur_freq; + int ret = 0; + + /* Here we write the clipping */ + /* Check if the old cooling action is same as new cooling action */ + if (ccdev->clock_state == cooling_state) + return 0; + + clip_freq = clock_cooling_get_frequency(ccdev, cooling_state); + if (!clip_freq) + return -EINVAL; + + cur_freq = clk_get_rate(ccdev->clk); + + mutex_lock(&ccdev->lock); + ccdev->clock_state = cooling_state; + ccdev->clock_val = clip_freq; + /* enforce clock level */ + if (cur_freq > clip_freq) + ret = clk_set_rate(ccdev->clk, clip_freq); + mutex_unlock(&ccdev->lock); + + return ret; +} + +/** + * clock_cooling_clock_notifier - notifier callback on clock rate changes. + * @nb: struct notifier_block * with callback info. + * @event: value showing clock event for which this function invoked. + * @data: callback-specific data + * + * Callback to hijack the notification on clock transition. + * Every time there is a clock change, we intercept all pre change events + * and block the transition in case the new rate infringes thermal limits. + * + * Return: NOTIFY_DONE (success) or NOTIFY_BAD (new_rate > thermal limit). + */ +static int clock_cooling_clock_notifier(struct notifier_block *nb, + unsigned long event, void *data) +{ + struct clk_notifier_data *ndata = data; + struct clock_cooling_device *ccdev = to_clock_cooling_device(nb); + + switch (event) { + case PRE_RATE_CHANGE: + /* + * checks on current state + * TODO: current method is not best we can find as it + * allows possibly voltage transitions, in case DVFS + * layer is also hijacking clock pre notifications. + */ + if (ndata->new_rate > ccdev->clock_val) + return NOTIFY_BAD; + /* fall through */ + case POST_RATE_CHANGE: + case ABORT_RATE_CHANGE: + default: + return NOTIFY_DONE; + } +} + +/* clock cooling device thermal callback functions are defined below */ + +/** + * clock_cooling_get_max_state - callback function to get the max cooling state. + * @cdev: thermal cooling device pointer. + * @state: fill this variable with the max cooling state. + * + * Callback for the thermal cooling device to return the clock + * max cooling state. + * + * Return: 0 on success, an error code otherwise. + */ +static int clock_cooling_get_max_state(struct thermal_cooling_device *cdev, + unsigned long *state) +{ + struct clock_cooling_device *ccdev = cdev->devdata; + unsigned long count = 0; + int ret; + + ret = clock_cooling_get_property(ccdev, 0, &count, GET_MAXL); + if (!ret) + *state = count; + + return ret; +} + +/** + * clock_cooling_get_cur_state - function to get the current cooling state. + * @cdev: thermal cooling device pointer. + * @state: fill this variable with the current cooling state. + * + * Callback for the thermal cooling device to return the clock + * current cooling state. + * + * Return: 0 (success) + */ +static int clock_cooling_get_cur_state(struct thermal_cooling_device *cdev, + unsigned long *state) +{ + struct clock_cooling_device *ccdev = cdev->devdata; + + *state = ccdev->clock_state; + + return 0; +} + +/** + * clock_cooling_set_cur_state - function to set the current cooling state. + * @cdev: thermal cooling device pointer. + * @state: set this variable to the current cooling state. + * + * Callback for the thermal cooling device to change the clock cooling + * current cooling state. + * + * Return: 0 on success, an error code otherwise. + */ +static int clock_cooling_set_cur_state(struct thermal_cooling_device *cdev, + unsigned long state) +{ + struct clock_cooling_device *clock_device = cdev->devdata; + + return clock_cooling_apply(clock_device, state); +} + +/* Bind clock callbacks to thermal cooling device ops */ +static struct thermal_cooling_device_ops const clock_cooling_ops = { + .get_max_state = clock_cooling_get_max_state, + .get_cur_state = clock_cooling_get_cur_state, + .set_cur_state = clock_cooling_set_cur_state, +}; + +/** + * clock_cooling_register - function to create clock cooling device. + * @dev: struct device pointer to the device used as clock cooling device. + * @clock_name: string containing the clock used as cooling mechanism. + * + * This interface function registers the clock cooling device with the name + * "thermal-clock-%x". The cooling device is based on clock frequencies. + * The struct device is assumed to be capable of DVFS transitions. + * The OPP layer is used to fetch and fill the available frequencies for + * the referred device. The ordered frequency table is used to control + * the clock cooling device cooling states and to limit clock transitions + * based on the cooling state requested by the thermal framework. + * + * Return: a valid struct thermal_cooling_device pointer on success, + * on failure, it returns a corresponding ERR_PTR(). + */ +struct thermal_cooling_device * +clock_cooling_register(struct device *dev, const char *clock_name) +{ + struct thermal_cooling_device *cdev; + struct clock_cooling_device *ccdev = NULL; + char dev_name[THERMAL_NAME_LENGTH]; + int ret = 0; + + ccdev = devm_kzalloc(dev, sizeof(*ccdev), GFP_KERNEL); + if (!ccdev) + return ERR_PTR(-ENOMEM); + + ccdev->dev = dev; + ccdev->clk = devm_clk_get(dev, clock_name); + if (IS_ERR(ccdev->clk)) + return ERR_CAST(ccdev->clk); + + ret = clock_cooling_get_idr(&ccdev->id); + if (ret) + return ERR_PTR(-EINVAL); + + snprintf(dev_name, sizeof(dev_name), "thermal-clock-%d", ccdev->id); + + cdev = thermal_cooling_device_register(dev_name, ccdev, + &clock_cooling_ops); + if (IS_ERR(cdev)) { + release_idr(ccdev->id); + return ERR_PTR(-EINVAL); + } + ccdev->cdev = cdev; + ccdev->clk_rate_change_nb.notifier_call = clock_cooling_clock_notifier; + + /* Assuming someone has already filled the opp table for this device */ + ret = dev_pm_opp_init_cpufreq_table(dev, &ccdev->freq_table); + if (ret) { + release_idr(ccdev->id); + return ERR_PTR(ret); + } + ccdev->clock_state = 0; + ccdev->clock_val = clock_cooling_get_frequency(ccdev, 0); + + clk_notifier_register(ccdev->clk, &ccdev->clk_rate_change_nb); + + return cdev; +} +EXPORT_SYMBOL_GPL(clock_cooling_register); + +/** + * clock_cooling_unregister - function to remove clock cooling device. + * @cdev: thermal cooling device pointer. + * + * This interface function unregisters the "thermal-clock-%x" cooling device. + */ +void clock_cooling_unregister(struct thermal_cooling_device *cdev) +{ + struct clock_cooling_device *ccdev; + + if (!cdev) + return; + + ccdev = cdev->devdata; + + clk_notifier_unregister(ccdev->clk, &ccdev->clk_rate_change_nb); + dev_pm_opp_free_cpufreq_table(ccdev->dev, &ccdev->freq_table); + + thermal_cooling_device_unregister(ccdev->cdev); + release_idr(ccdev->id); +} +EXPORT_SYMBOL_GPL(clock_cooling_unregister); |