530 lines
14 KiB
C
530 lines
14 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* devfreq_cooling: Thermal cooling device implementation for devices using
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* devfreq
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*
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* Copyright (C) 2014-2015 ARM Limited
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*
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* TODO:
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* - If OPPs are added or removed after devfreq cooling has
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* registered, the devfreq cooling won't react to it.
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*/
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#include <linux/devfreq.h>
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#include <linux/devfreq_cooling.h>
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#include <linux/energy_model.h>
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#include <linux/export.h>
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#include <linux/slab.h>
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#include <linux/pm_opp.h>
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#include <linux/pm_qos.h>
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#include <linux/thermal.h>
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#include <linux/units.h>
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#include <trace/events/thermal.h>
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#define SCALE_ERROR_MITIGATION 100
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/**
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* struct devfreq_cooling_device - Devfreq cooling device
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* devfreq_cooling_device registered.
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* @cdev: Pointer to associated thermal cooling device.
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* @devfreq: Pointer to associated devfreq device.
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* @cooling_state: Current cooling state.
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* @freq_table: Pointer to a table with the frequencies sorted in descending
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* order. You can index the table by cooling device state
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* @max_state: It is the last index, that is, one less than the number of the
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* OPPs
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* @power_ops: Pointer to devfreq_cooling_power, a more precised model.
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* @res_util: Resource utilization scaling factor for the power.
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* It is multiplied by 100 to minimize the error. It is used
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* for estimation of the power budget instead of using
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* 'utilization' (which is 'busy_time' / 'total_time').
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* The 'res_util' range is from 100 to power * 100 for the
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* corresponding 'state'.
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* @capped_state: index to cooling state with in dynamic power budget
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* @req_max_freq: PM QoS request for limiting the maximum frequency
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* of the devfreq device.
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* @em_pd: Energy Model for the associated Devfreq device
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*/
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struct devfreq_cooling_device {
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struct thermal_cooling_device *cdev;
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struct devfreq *devfreq;
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unsigned long cooling_state;
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u32 *freq_table;
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size_t max_state;
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struct devfreq_cooling_power *power_ops;
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u32 res_util;
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int capped_state;
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struct dev_pm_qos_request req_max_freq;
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struct em_perf_domain *em_pd;
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};
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static int devfreq_cooling_get_max_state(struct thermal_cooling_device *cdev,
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unsigned long *state)
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{
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struct devfreq_cooling_device *dfc = cdev->devdata;
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*state = dfc->max_state;
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return 0;
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}
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static int devfreq_cooling_get_cur_state(struct thermal_cooling_device *cdev,
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unsigned long *state)
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{
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struct devfreq_cooling_device *dfc = cdev->devdata;
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*state = dfc->cooling_state;
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return 0;
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}
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static int devfreq_cooling_set_cur_state(struct thermal_cooling_device *cdev,
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unsigned long state)
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{
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struct devfreq_cooling_device *dfc = cdev->devdata;
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struct devfreq *df = dfc->devfreq;
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struct device *dev = df->dev.parent;
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unsigned long freq;
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int perf_idx;
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if (state == dfc->cooling_state)
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return 0;
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dev_dbg(dev, "Setting cooling state %lu\n", state);
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if (state > dfc->max_state)
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return -EINVAL;
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if (dfc->em_pd) {
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perf_idx = dfc->max_state - state;
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freq = dfc->em_pd->table[perf_idx].frequency * 1000;
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} else {
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freq = dfc->freq_table[state];
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}
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dev_pm_qos_update_request(&dfc->req_max_freq,
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DIV_ROUND_UP(freq, HZ_PER_KHZ));
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dfc->cooling_state = state;
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return 0;
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}
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/**
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* get_perf_idx() - get the performance index corresponding to a frequency
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* @em_pd: Pointer to device's Energy Model
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* @freq: frequency in kHz
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*
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* Return: the performance index associated with the @freq, or
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* -EINVAL if it wasn't found.
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*/
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static int get_perf_idx(struct em_perf_domain *em_pd, unsigned long freq)
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{
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int i;
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for (i = 0; i < em_pd->nr_perf_states; i++) {
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if (em_pd->table[i].frequency == freq)
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return i;
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}
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return -EINVAL;
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}
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static unsigned long get_voltage(struct devfreq *df, unsigned long freq)
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{
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struct device *dev = df->dev.parent;
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unsigned long voltage;
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struct dev_pm_opp *opp;
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opp = dev_pm_opp_find_freq_exact(dev, freq, true);
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if (PTR_ERR(opp) == -ERANGE)
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opp = dev_pm_opp_find_freq_exact(dev, freq, false);
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if (IS_ERR(opp)) {
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dev_err_ratelimited(dev, "Failed to find OPP for frequency %lu: %ld\n",
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freq, PTR_ERR(opp));
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return 0;
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}
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voltage = dev_pm_opp_get_voltage(opp) / 1000; /* mV */
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dev_pm_opp_put(opp);
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if (voltage == 0) {
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dev_err_ratelimited(dev,
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"Failed to get voltage for frequency %lu\n",
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freq);
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}
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return voltage;
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}
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static void _normalize_load(struct devfreq_dev_status *status)
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{
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if (status->total_time > 0xfffff) {
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status->total_time >>= 10;
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status->busy_time >>= 10;
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}
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status->busy_time <<= 10;
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status->busy_time /= status->total_time ? : 1;
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status->busy_time = status->busy_time ? : 1;
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status->total_time = 1024;
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}
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static int devfreq_cooling_get_requested_power(struct thermal_cooling_device *cdev,
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u32 *power)
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{
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struct devfreq_cooling_device *dfc = cdev->devdata;
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struct devfreq *df = dfc->devfreq;
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struct devfreq_dev_status status;
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unsigned long state;
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unsigned long freq;
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unsigned long voltage;
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int res, perf_idx;
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mutex_lock(&df->lock);
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status = df->last_status;
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mutex_unlock(&df->lock);
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freq = status.current_frequency;
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if (dfc->power_ops && dfc->power_ops->get_real_power) {
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voltage = get_voltage(df, freq);
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if (voltage == 0) {
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res = -EINVAL;
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goto fail;
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}
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res = dfc->power_ops->get_real_power(df, power, freq, voltage);
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if (!res) {
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state = dfc->capped_state;
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dfc->res_util = dfc->em_pd->table[state].power;
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dfc->res_util *= SCALE_ERROR_MITIGATION;
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if (*power > 1)
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dfc->res_util /= *power;
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} else {
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goto fail;
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}
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} else {
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/* Energy Model frequencies are in kHz */
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perf_idx = get_perf_idx(dfc->em_pd, freq / 1000);
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if (perf_idx < 0) {
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res = -EAGAIN;
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goto fail;
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}
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_normalize_load(&status);
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/* Scale power for utilization */
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*power = dfc->em_pd->table[perf_idx].power;
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*power *= status.busy_time;
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*power >>= 10;
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}
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trace_thermal_power_devfreq_get_power(cdev, &status, freq, *power);
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return 0;
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fail:
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/* It is safe to set max in this case */
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dfc->res_util = SCALE_ERROR_MITIGATION;
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return res;
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}
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static int devfreq_cooling_state2power(struct thermal_cooling_device *cdev,
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unsigned long state, u32 *power)
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{
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struct devfreq_cooling_device *dfc = cdev->devdata;
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int perf_idx;
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if (state > dfc->max_state)
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return -EINVAL;
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perf_idx = dfc->max_state - state;
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*power = dfc->em_pd->table[perf_idx].power;
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return 0;
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}
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static int devfreq_cooling_power2state(struct thermal_cooling_device *cdev,
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u32 power, unsigned long *state)
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{
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struct devfreq_cooling_device *dfc = cdev->devdata;
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struct devfreq *df = dfc->devfreq;
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struct devfreq_dev_status status;
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unsigned long freq;
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s32 est_power;
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int i;
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mutex_lock(&df->lock);
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status = df->last_status;
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mutex_unlock(&df->lock);
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freq = status.current_frequency;
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if (dfc->power_ops && dfc->power_ops->get_real_power) {
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/* Scale for resource utilization */
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est_power = power * dfc->res_util;
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est_power /= SCALE_ERROR_MITIGATION;
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} else {
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/* Scale dynamic power for utilization */
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_normalize_load(&status);
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est_power = power << 10;
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est_power /= status.busy_time;
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}
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/*
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* Find the first cooling state that is within the power
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* budget. The EM power table is sorted ascending.
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*/
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for (i = dfc->max_state; i > 0; i--)
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if (est_power >= dfc->em_pd->table[i].power)
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break;
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*state = dfc->max_state - i;
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dfc->capped_state = *state;
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trace_thermal_power_devfreq_limit(cdev, freq, *state, power);
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return 0;
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}
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static struct thermal_cooling_device_ops devfreq_cooling_ops = {
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.get_max_state = devfreq_cooling_get_max_state,
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.get_cur_state = devfreq_cooling_get_cur_state,
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.set_cur_state = devfreq_cooling_set_cur_state,
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};
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/**
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* devfreq_cooling_gen_tables() - Generate frequency table.
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* @dfc: Pointer to devfreq cooling device.
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* @num_opps: Number of OPPs
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*
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* Generate frequency table which holds the frequencies in descending
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* order. That way its indexed by cooling device state. This is for
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* compatibility with drivers which do not register Energy Model.
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*
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* Return: 0 on success, negative error code on failure.
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*/
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static int devfreq_cooling_gen_tables(struct devfreq_cooling_device *dfc,
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int num_opps)
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{
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struct devfreq *df = dfc->devfreq;
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struct device *dev = df->dev.parent;
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unsigned long freq;
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int i;
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dfc->freq_table = kcalloc(num_opps, sizeof(*dfc->freq_table),
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GFP_KERNEL);
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if (!dfc->freq_table)
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return -ENOMEM;
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for (i = 0, freq = ULONG_MAX; i < num_opps; i++, freq--) {
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struct dev_pm_opp *opp;
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opp = dev_pm_opp_find_freq_floor(dev, &freq);
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if (IS_ERR(opp)) {
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kfree(dfc->freq_table);
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return PTR_ERR(opp);
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}
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dev_pm_opp_put(opp);
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dfc->freq_table[i] = freq;
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}
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return 0;
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}
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/**
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* of_devfreq_cooling_register_power() - Register devfreq cooling device,
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* with OF and power information.
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* @np: Pointer to OF device_node.
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* @df: Pointer to devfreq device.
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* @dfc_power: Pointer to devfreq_cooling_power.
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*
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* Register a devfreq cooling device. The available OPPs must be
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* registered on the device.
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*
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* If @dfc_power is provided, the cooling device is registered with the
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* power extensions. For the power extensions to work correctly,
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* devfreq should use the simple_ondemand governor, other governors
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* are not currently supported.
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*/
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struct thermal_cooling_device *
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of_devfreq_cooling_register_power(struct device_node *np, struct devfreq *df,
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struct devfreq_cooling_power *dfc_power)
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{
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struct thermal_cooling_device *cdev;
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struct device *dev = df->dev.parent;
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struct devfreq_cooling_device *dfc;
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char *name;
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int err, num_opps;
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dfc = kzalloc(sizeof(*dfc), GFP_KERNEL);
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if (!dfc)
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return ERR_PTR(-ENOMEM);
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dfc->devfreq = df;
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dfc->em_pd = em_pd_get(dev);
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if (dfc->em_pd) {
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devfreq_cooling_ops.get_requested_power =
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devfreq_cooling_get_requested_power;
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devfreq_cooling_ops.state2power = devfreq_cooling_state2power;
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devfreq_cooling_ops.power2state = devfreq_cooling_power2state;
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dfc->power_ops = dfc_power;
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num_opps = em_pd_nr_perf_states(dfc->em_pd);
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} else {
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/* Backward compatibility for drivers which do not use IPA */
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dev_dbg(dev, "missing EM for cooling device\n");
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num_opps = dev_pm_opp_get_opp_count(dev);
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err = devfreq_cooling_gen_tables(dfc, num_opps);
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if (err)
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goto free_dfc;
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}
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if (num_opps <= 0) {
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err = -EINVAL;
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goto free_dfc;
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}
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/* max_state is an index, not a counter */
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dfc->max_state = num_opps - 1;
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err = dev_pm_qos_add_request(dev, &dfc->req_max_freq,
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DEV_PM_QOS_MAX_FREQUENCY,
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PM_QOS_MAX_FREQUENCY_DEFAULT_VALUE);
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if (err < 0)
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goto free_table;
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err = -ENOMEM;
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name = kasprintf(GFP_KERNEL, "devfreq-%s", dev_name(dev));
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if (!name)
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goto remove_qos_req;
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cdev = thermal_of_cooling_device_register(np, name, dfc,
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&devfreq_cooling_ops);
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kfree(name);
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if (IS_ERR(cdev)) {
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err = PTR_ERR(cdev);
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dev_err(dev,
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"Failed to register devfreq cooling device (%d)\n",
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err);
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goto remove_qos_req;
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}
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dfc->cdev = cdev;
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return cdev;
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remove_qos_req:
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dev_pm_qos_remove_request(&dfc->req_max_freq);
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free_table:
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kfree(dfc->freq_table);
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free_dfc:
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kfree(dfc);
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return ERR_PTR(err);
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}
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EXPORT_SYMBOL_GPL(of_devfreq_cooling_register_power);
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/**
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* of_devfreq_cooling_register() - Register devfreq cooling device,
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* with OF information.
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* @np: Pointer to OF device_node.
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* @df: Pointer to devfreq device.
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*/
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struct thermal_cooling_device *
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of_devfreq_cooling_register(struct device_node *np, struct devfreq *df)
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{
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return of_devfreq_cooling_register_power(np, df, NULL);
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}
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EXPORT_SYMBOL_GPL(of_devfreq_cooling_register);
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/**
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* devfreq_cooling_register() - Register devfreq cooling device.
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* @df: Pointer to devfreq device.
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*/
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struct thermal_cooling_device *devfreq_cooling_register(struct devfreq *df)
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{
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return of_devfreq_cooling_register(NULL, df);
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}
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EXPORT_SYMBOL_GPL(devfreq_cooling_register);
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/**
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* devfreq_cooling_em_register() - Register devfreq cooling device with
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* power information and automatically register Energy Model (EM)
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* @df: Pointer to devfreq device.
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* @dfc_power: Pointer to devfreq_cooling_power.
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*
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* Register a devfreq cooling device and automatically register EM. The
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* available OPPs must be registered for the device.
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*
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* If @dfc_power is provided, the cooling device is registered with the
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* power extensions. It is using the simple Energy Model which requires
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* "dynamic-power-coefficient" a devicetree property. To not break drivers
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* which miss that DT property, the function won't bail out when the EM
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* registration failed. The cooling device will be registered if everything
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* else is OK.
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*/
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struct thermal_cooling_device *
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devfreq_cooling_em_register(struct devfreq *df,
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struct devfreq_cooling_power *dfc_power)
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{
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struct thermal_cooling_device *cdev;
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struct device *dev;
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int ret;
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if (IS_ERR_OR_NULL(df))
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return ERR_PTR(-EINVAL);
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dev = df->dev.parent;
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ret = dev_pm_opp_of_register_em(dev, NULL);
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if (ret)
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dev_dbg(dev, "Unable to register EM for devfreq cooling device (%d)\n",
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ret);
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cdev = of_devfreq_cooling_register_power(dev->of_node, df, dfc_power);
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if (IS_ERR_OR_NULL(cdev))
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em_dev_unregister_perf_domain(dev);
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return cdev;
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}
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EXPORT_SYMBOL_GPL(devfreq_cooling_em_register);
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/**
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* devfreq_cooling_unregister() - Unregister devfreq cooling device.
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* @cdev: Pointer to devfreq cooling device to unregister.
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*
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* Unregisters devfreq cooling device and related Energy Model if it was
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* present.
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*/
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void devfreq_cooling_unregister(struct thermal_cooling_device *cdev)
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{
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struct devfreq_cooling_device *dfc;
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struct device *dev;
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if (IS_ERR_OR_NULL(cdev))
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return;
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dfc = cdev->devdata;
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dev = dfc->devfreq->dev.parent;
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thermal_cooling_device_unregister(dfc->cdev);
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dev_pm_qos_remove_request(&dfc->req_max_freq);
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|
|
|
em_dev_unregister_perf_domain(dev);
|
|
|
|
kfree(dfc->freq_table);
|
|
kfree(dfc);
|
|
}
|
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EXPORT_SYMBOL_GPL(devfreq_cooling_unregister);
|