2be83da85a
This patch introduces a new interface for device drivers connected to
devfreq_cooling in the thermal framework: get_real_power().
Some devices have more sophisticated methods (like power counters)
to approximate the actual power that they use.
In the previous implementation we had a pre-calculated power
table which was then scaled by 'utilization'
('busy_time' and 'total_time' taken from devfreq 'last_status').
With this new interface the driver can provide more precise data
regarding actual power to the thermal governor every time the power
budget is calculated. We then use this value and calculate the real
resource utilization scaling factor.
Reviewed-by: Chris Diamand <chris.diamand@arm.com>
Acked-by: Javi Merino <javi.merino@kernel.org>
Signed-off-by: Lukasz Luba <lukasz.luba@arm.com>
609 lines
16 KiB
C
609 lines
16 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/idr.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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#define SCALE_ERROR_MITIGATION 100
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static DEFINE_IDA(devfreq_ida);
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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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* @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_table[state] * 100)
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* for the corresponding 'state'.
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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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u32 res_util;
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int capped_state;
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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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opp = dev_pm_opp_find_freq_exact(dev, freq, !want_enable);
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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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dev_pm_opp_put(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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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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/**
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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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unsigned long voltage;
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if (!dfc->power_ops->get_static_power)
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return 0;
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voltage = get_voltage(df, freq);
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if (voltage == 0)
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return 0;
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return dfc->power_ops->get_static_power(df, 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(dfc->devfreq, freq,
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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 inline unsigned long get_total_power(struct devfreq_cooling_device *dfc,
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unsigned long freq,
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unsigned long voltage)
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{
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return get_static_power(dfc, freq) + get_dynamic_power(dfc, freq,
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voltage);
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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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unsigned long voltage;
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u32 dyn_power = 0;
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u32 static_power = 0;
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int res;
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state = freq_get_state(dfc, freq);
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if (state == THERMAL_CSTATE_INVALID) {
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res = -EAGAIN;
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goto fail;
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}
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if (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->power_table[state];
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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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dyn_power = dfc->power_table[state];
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/* Scale dynamic power for utilization */
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dyn_power *= status->busy_time;
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dyn_power /= 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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*power = dyn_power + static_power;
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}
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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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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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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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s32 est_power;
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int i;
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if (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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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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est_power = (dyn_power * status->total_time) / 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 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 (est_power >= dfc->power_table[i])
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break;
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*state = i;
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dfc->capped_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, voltage;
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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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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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dev_pm_opp_put(opp);
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if (dfc->power_ops) {
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if (dfc->power_ops->get_real_power)
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power = get_total_power(dfc, freq, voltage);
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else
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power = get_dynamic_power(dfc, freq, voltage);
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dev_dbg(dev, "Power table: %lu MHz @ %lu mV: %lu = %lu mW\n",
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freq / 1000000, voltage, power, power);
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power_table[i] = power;
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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);
|
|
if (!dfc)
|
|
return ERR_PTR(-ENOMEM);
|
|
|
|
dfc->devfreq = df;
|
|
|
|
if (dfc_power) {
|
|
dfc->power_ops = dfc_power;
|
|
|
|
devfreq_cooling_ops.get_requested_power =
|
|
devfreq_cooling_get_requested_power;
|
|
devfreq_cooling_ops.state2power = devfreq_cooling_state2power;
|
|
devfreq_cooling_ops.power2state = devfreq_cooling_power2state;
|
|
}
|
|
|
|
err = devfreq_cooling_gen_tables(dfc);
|
|
if (err)
|
|
goto free_dfc;
|
|
|
|
err = ida_simple_get(&devfreq_ida, 0, 0, GFP_KERNEL);
|
|
if (err < 0)
|
|
goto free_tables;
|
|
dfc->id = err;
|
|
|
|
snprintf(dev_name, sizeof(dev_name), "thermal-devfreq-%d", dfc->id);
|
|
|
|
cdev = thermal_of_cooling_device_register(np, dev_name, dfc,
|
|
&devfreq_cooling_ops);
|
|
if (IS_ERR(cdev)) {
|
|
err = PTR_ERR(cdev);
|
|
dev_err(df->dev.parent,
|
|
"Failed to register devfreq cooling device (%d)\n",
|
|
err);
|
|
goto release_ida;
|
|
}
|
|
|
|
dfc->cdev = cdev;
|
|
|
|
return cdev;
|
|
|
|
release_ida:
|
|
ida_simple_remove(&devfreq_ida, dfc->id);
|
|
free_tables:
|
|
kfree(dfc->power_table);
|
|
kfree(dfc->freq_table);
|
|
free_dfc:
|
|
kfree(dfc);
|
|
|
|
return ERR_PTR(err);
|
|
}
|
|
EXPORT_SYMBOL_GPL(of_devfreq_cooling_register_power);
|
|
|
|
/**
|
|
* of_devfreq_cooling_register() - Register devfreq cooling device,
|
|
* with OF information.
|
|
* @np: Pointer to OF device_node.
|
|
* @df: Pointer to devfreq device.
|
|
*/
|
|
struct thermal_cooling_device *
|
|
of_devfreq_cooling_register(struct device_node *np, struct devfreq *df)
|
|
{
|
|
return of_devfreq_cooling_register_power(np, df, NULL);
|
|
}
|
|
EXPORT_SYMBOL_GPL(of_devfreq_cooling_register);
|
|
|
|
/**
|
|
* devfreq_cooling_register() - Register devfreq cooling device.
|
|
* @df: Pointer to devfreq device.
|
|
*/
|
|
struct thermal_cooling_device *devfreq_cooling_register(struct devfreq *df)
|
|
{
|
|
return of_devfreq_cooling_register(NULL, df);
|
|
}
|
|
EXPORT_SYMBOL_GPL(devfreq_cooling_register);
|
|
|
|
/**
|
|
* devfreq_cooling_unregister() - Unregister devfreq cooling device.
|
|
* @dfc: Pointer to devfreq cooling device to unregister.
|
|
*/
|
|
void devfreq_cooling_unregister(struct thermal_cooling_device *cdev)
|
|
{
|
|
struct devfreq_cooling_device *dfc;
|
|
|
|
if (!cdev)
|
|
return;
|
|
|
|
dfc = cdev->devdata;
|
|
|
|
thermal_cooling_device_unregister(dfc->cdev);
|
|
ida_simple_remove(&devfreq_ida, dfc->id);
|
|
kfree(dfc->power_table);
|
|
kfree(dfc->freq_table);
|
|
|
|
kfree(dfc);
|
|
}
|
|
EXPORT_SYMBOL_GPL(devfreq_cooling_unregister);
|