574 lines
15 KiB
C
574 lines
15 KiB
C
/*
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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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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* This program is distributed "as is" WITHOUT ANY WARRANTY of any
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* kind, whether express or implied; without even the implied warranty
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* of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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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/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/thermal.h>
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#include <trace/events/thermal.h>
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static DEFINE_MUTEX(devfreq_lock);
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static DEFINE_IDR(devfreq_idr);
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/**
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* struct devfreq_cooling_device - Devfreq cooling device
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* @id: unique integer value corresponding to each
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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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* @power_table: Pointer to table with maximum power draw for each
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* cooling state. State is the index into the table, and
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* the power is in mW.
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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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* @freq_table_size: Size of the @freq_table and @power_table
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* @power_ops: Pointer to devfreq_cooling_power, used to generate the
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* @power_table.
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*/
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struct devfreq_cooling_device {
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int id;
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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 *power_table;
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u32 *freq_table;
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size_t freq_table_size;
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struct devfreq_cooling_power *power_ops;
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};
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/**
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* get_idr - function to get a unique id.
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* @idr: struct idr * handle used to create a id.
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* @id: int * value generated by this function.
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*
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* This function will populate @id with an unique
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* id, using the idr API.
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*
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* Return: 0 on success, an error code on failure.
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*/
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static int get_idr(struct idr *idr, int *id)
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{
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int ret;
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mutex_lock(&devfreq_lock);
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ret = idr_alloc(idr, NULL, 0, 0, GFP_KERNEL);
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mutex_unlock(&devfreq_lock);
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if (unlikely(ret < 0))
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return ret;
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*id = ret;
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return 0;
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}
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/**
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* release_idr - function to free the unique id.
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* @idr: struct idr * handle used for creating the id.
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* @id: int value representing the unique id.
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*/
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static void release_idr(struct idr *idr, int id)
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{
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mutex_lock(&devfreq_lock);
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idr_remove(idr, id);
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mutex_unlock(&devfreq_lock);
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}
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/**
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* partition_enable_opps() - disable all opps above a given state
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* @dfc: Pointer to devfreq we are operating on
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* @cdev_state: cooling device state we're setting
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*
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* Go through the OPPs of the device, enabling all OPPs until
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* @cdev_state and disabling those frequencies above it.
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*/
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static int partition_enable_opps(struct devfreq_cooling_device *dfc,
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unsigned long cdev_state)
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{
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int i;
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struct device *dev = dfc->devfreq->dev.parent;
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for (i = 0; i < dfc->freq_table_size; i++) {
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struct dev_pm_opp *opp;
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int ret = 0;
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unsigned int freq = dfc->freq_table[i];
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bool want_enable = i >= cdev_state ? true : false;
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rcu_read_lock();
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opp = dev_pm_opp_find_freq_exact(dev, freq, !want_enable);
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rcu_read_unlock();
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if (PTR_ERR(opp) == -ERANGE)
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continue;
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else if (IS_ERR(opp))
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return PTR_ERR(opp);
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if (want_enable)
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ret = dev_pm_opp_enable(dev, freq);
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else
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ret = dev_pm_opp_disable(dev, freq);
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if (ret)
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return ret;
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}
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return 0;
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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->freq_table_size - 1;
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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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int ret;
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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->freq_table_size)
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return -EINVAL;
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ret = partition_enable_opps(dfc, state);
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if (ret)
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return ret;
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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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* freq_get_state() - get the cooling state corresponding to a frequency
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* @dfc: Pointer to devfreq cooling device
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* @freq: frequency in Hz
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*
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* Return: the cooling state associated with the @freq, or
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* THERMAL_CSTATE_INVALID if it wasn't found.
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*/
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static unsigned long
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freq_get_state(struct devfreq_cooling_device *dfc, unsigned long freq)
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{
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int i;
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for (i = 0; i < dfc->freq_table_size; i++) {
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if (dfc->freq_table[i] == freq)
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return i;
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}
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return THERMAL_CSTATE_INVALID;
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}
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/**
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* get_static_power() - calculate the static power
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* @dfc: Pointer to devfreq cooling device
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* @freq: Frequency in Hz
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*
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* Calculate the static power in milliwatts using the supplied
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* get_static_power(). The current voltage is calculated using the
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* OPP library. If no get_static_power() was supplied, assume the
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* static power is negligible.
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*/
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static unsigned long
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get_static_power(struct devfreq_cooling_device *dfc, unsigned long freq)
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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 voltage;
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struct dev_pm_opp *opp;
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if (!dfc->power_ops->get_static_power)
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return 0;
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rcu_read_lock();
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opp = dev_pm_opp_find_freq_exact(dev, freq, true);
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if (IS_ERR(opp) && (PTR_ERR(opp) == -ERANGE))
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opp = dev_pm_opp_find_freq_exact(dev, freq, false);
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voltage = dev_pm_opp_get_voltage(opp) / 1000; /* mV */
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rcu_read_unlock();
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if (voltage == 0) {
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dev_warn_ratelimited(dev,
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"Failed to get voltage for frequency %lu: %ld\n",
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freq, IS_ERR(opp) ? PTR_ERR(opp) : 0);
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return 0;
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}
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return dfc->power_ops->get_static_power(voltage);
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}
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/**
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* get_dynamic_power - calculate the dynamic power
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* @dfc: Pointer to devfreq cooling device
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* @freq: Frequency in Hz
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* @voltage: Voltage in millivolts
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*
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* Calculate the dynamic power in milliwatts consumed by the device at
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* frequency @freq and voltage @voltage. If the get_dynamic_power()
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* was supplied as part of the devfreq_cooling_power struct, then that
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* function is used. Otherwise, a simple power model (Pdyn = Coeff *
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* Voltage^2 * Frequency) is used.
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*/
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static unsigned long
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get_dynamic_power(struct devfreq_cooling_device *dfc, unsigned long freq,
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unsigned long voltage)
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{
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u64 power;
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u32 freq_mhz;
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struct devfreq_cooling_power *dfc_power = dfc->power_ops;
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if (dfc_power->get_dynamic_power)
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return dfc_power->get_dynamic_power(freq, voltage);
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freq_mhz = freq / 1000000;
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power = (u64)dfc_power->dyn_power_coeff * freq_mhz * voltage * voltage;
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do_div(power, 1000000000);
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return power;
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}
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static int devfreq_cooling_get_requested_power(struct thermal_cooling_device *cdev,
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struct thermal_zone_device *tz,
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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 = &df->last_status;
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unsigned long state;
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unsigned long freq = status->current_frequency;
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u32 dyn_power, static_power;
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/* Get dynamic power for state */
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state = freq_get_state(dfc, freq);
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if (state == THERMAL_CSTATE_INVALID)
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return -EAGAIN;
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dyn_power = dfc->power_table[state];
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/* Scale dynamic power for utilization */
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dyn_power = (dyn_power * status->busy_time) / status->total_time;
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/* Get static power */
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static_power = get_static_power(dfc, freq);
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trace_thermal_power_devfreq_get_power(cdev, status, freq, dyn_power,
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static_power);
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*power = dyn_power + static_power;
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return 0;
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}
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static int devfreq_cooling_state2power(struct thermal_cooling_device *cdev,
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struct thermal_zone_device *tz,
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unsigned long state,
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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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unsigned long freq;
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u32 static_power;
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if (state >= dfc->freq_table_size)
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return -EINVAL;
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freq = dfc->freq_table[state];
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static_power = get_static_power(dfc, freq);
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*power = dfc->power_table[state] + static_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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struct thermal_zone_device *tz,
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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 = &df->last_status;
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unsigned long freq = status->current_frequency;
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unsigned long busy_time;
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s32 dyn_power;
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u32 static_power;
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int i;
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static_power = get_static_power(dfc, freq);
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dyn_power = power - static_power;
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dyn_power = dyn_power > 0 ? dyn_power : 0;
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/* Scale dynamic power for utilization */
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busy_time = status->busy_time ?: 1;
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dyn_power = (dyn_power * status->total_time) / busy_time;
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/*
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* Find the first cooling state that is within the power
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* budget for dynamic power.
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*/
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for (i = 0; i < dfc->freq_table_size - 1; i++)
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if (dyn_power >= dfc->power_table[i])
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break;
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*state = i;
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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 power and freq tables.
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* @dfc: Pointer to devfreq cooling device.
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*
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* Generate power and frequency tables: the power table hold the
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* device's maximum power usage at each cooling state (OPP). The
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* static and dynamic power using the appropriate voltage and
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* frequency for the state, is acquired from the struct
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* devfreq_cooling_power, and summed to make the maximum power draw.
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*
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* The frequency table holds the frequencies in descending order.
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* That way its indexed by cooling device state.
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*
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* The tables are malloced, and pointers put in dfc. They must be
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* freed when unregistering the devfreq cooling device.
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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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{
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struct devfreq *df = dfc->devfreq;
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struct device *dev = df->dev.parent;
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int ret, num_opps;
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unsigned long freq;
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u32 *power_table = NULL;
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u32 *freq_table;
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int i;
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num_opps = dev_pm_opp_get_opp_count(dev);
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if (dfc->power_ops) {
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power_table = kcalloc(num_opps, sizeof(*power_table),
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GFP_KERNEL);
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if (!power_table)
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return -ENOMEM;
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}
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freq_table = kcalloc(num_opps, sizeof(*freq_table),
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GFP_KERNEL);
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if (!freq_table) {
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ret = -ENOMEM;
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goto free_power_table;
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}
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for (i = 0, freq = ULONG_MAX; i < num_opps; i++, freq--) {
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unsigned long power_dyn, voltage;
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struct dev_pm_opp *opp;
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rcu_read_lock();
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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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rcu_read_unlock();
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ret = PTR_ERR(opp);
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goto free_tables;
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}
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voltage = dev_pm_opp_get_voltage(opp) / 1000; /* mV */
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rcu_read_unlock();
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if (dfc->power_ops) {
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power_dyn = get_dynamic_power(dfc, freq, voltage);
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dev_dbg(dev, "Dynamic power table: %lu MHz @ %lu mV: %lu = %lu mW\n",
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freq / 1000000, voltage, power_dyn, power_dyn);
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power_table[i] = power_dyn;
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}
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freq_table[i] = freq;
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}
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if (dfc->power_ops)
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dfc->power_table = power_table;
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dfc->freq_table = freq_table;
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dfc->freq_table_size = num_opps;
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return 0;
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free_tables:
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kfree(freq_table);
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free_power_table:
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kfree(power_table);
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return ret;
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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 devfreq_cooling_device *dfc;
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char dev_name[THERMAL_NAME_LENGTH];
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int err;
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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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if (dfc_power) {
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dfc->power_ops = dfc_power;
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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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}
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err = devfreq_cooling_gen_tables(dfc);
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if (err)
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goto free_dfc;
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err = get_idr(&devfreq_idr, &dfc->id);
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if (err)
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goto free_tables;
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snprintf(dev_name, sizeof(dev_name), "thermal-devfreq-%d", dfc->id);
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cdev = thermal_of_cooling_device_register(np, dev_name, dfc,
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&devfreq_cooling_ops);
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if (IS_ERR(cdev)) {
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err = PTR_ERR(cdev);
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dev_err(df->dev.parent,
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"Failed to register devfreq cooling device (%d)\n",
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err);
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goto release_idr;
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}
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dfc->cdev = cdev;
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return cdev;
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release_idr:
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release_idr(&devfreq_idr, dfc->id);
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free_tables:
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kfree(dfc->power_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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/**
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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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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_unregister() - Unregister devfreq cooling device.
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|
* @dfc: Pointer to devfreq cooling device to unregister.
|
|
*/
|
|
void devfreq_cooling_unregister(struct thermal_cooling_device *cdev)
|
|
{
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|
struct devfreq_cooling_device *dfc;
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|
|
|
if (!cdev)
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return;
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|
|
|
dfc = cdev->devdata;
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|
|
|
thermal_cooling_device_unregister(dfc->cdev);
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|
release_idr(&devfreq_idr, dfc->id);
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|
kfree(dfc->power_table);
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|
kfree(dfc->freq_table);
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|
|
|
kfree(dfc);
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}
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EXPORT_SYMBOL_GPL(devfreq_cooling_unregister);
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