/*
* devfreq_cooling: Thermal cooling device implementation for devices using
* devfreq
*
* Copyright (C) 2014-2015 ARM Limited
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* This program is distributed "as is" WITHOUT ANY WARRANTY of any
* kind, whether express or implied; without even the implied warranty
* of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* TODO:
* - If OPPs are added or removed after devfreq cooling has
* registered, the devfreq cooling won't react to it.
*/
#include <linux/devfreq.h>
#include <linux/devfreq_cooling.h>
#include <linux/export.h>
#include <linux/idr.h>
#include <linux/slab.h>
#include <linux/pm_opp.h>
#include <linux/thermal.h>
#include <trace/events/thermal.h>
#define SCALE_ERROR_MITIGATION 100
static DEFINE_IDA(devfreq_ida);
/**
* struct devfreq_cooling_device - Devfreq cooling device
* @id: unique integer value corresponding to each
* devfreq_cooling_device registered.
* @cdev: Pointer to associated thermal cooling device.
* @devfreq: Pointer to associated devfreq device.
* @cooling_state: Current cooling state.
* @power_table: Pointer to table with maximum power draw for each
* cooling state. State is the index into the table, and
* the power is in mW.
* @freq_table: Pointer to a table with the frequencies sorted in descending
* order. You can index the table by cooling device state
* @freq_table_size: Size of the @freq_table and @power_table
* @power_ops: Pointer to devfreq_cooling_power, used to generate the
* @power_table.
* @res_util: Resource utilization scaling factor for the power.
* It is multiplied by 100 to minimize the error. It is used
* for estimation of the power budget instead of using
* 'utilization' (which is 'busy_time / 'total_time').
* The 'res_util' range is from 100 to (power_table[state] * 100)
* for the corresponding 'state'.
*/
struct devfreq_cooling_device {
int id;
struct thermal_cooling_device *cdev;
struct devfreq *devfreq;
unsigned long cooling_state;
u32 *power_table;
u32 *freq_table;
size_t freq_table_size;
struct devfreq_cooling_power *power_ops;
u32 res_util;
int capped_state;
};
/**
* partition_enable_opps() - disable all opps above a given state
* @dfc: Pointer to devfreq we are operating on
* @cdev_state: cooling device state we're setting
*
* Go through the OPPs of the device, enabling all OPPs until
* @cdev_state and disabling those frequencies above it.
*/
static int partition_enable_opps(struct devfreq_cooling_device *dfc,
unsigned long cdev_state)
{
int i;
struct device *dev = dfc->devfreq->dev.parent;
for (i = 0; i < dfc->freq_table_size; i++) {
struct dev_pm_opp *opp;
int ret = 0;
unsigned int freq = dfc->freq_table[i];
bool want_enable = i >= cdev_state ? true : false;
opp = dev_pm_opp_find_freq_exact(dev, freq, !want_enable);
if (PTR_ERR(opp) == -ERANGE)
continue;
else if (IS_ERR(opp))
return PTR_ERR(opp);
dev_pm_opp_put(opp);
if (want_enable)
ret = dev_pm_opp_enable(dev, freq);
else
ret = dev_pm_opp_disable(dev, freq);
if (ret)
return ret;
}
return 0;
}
static int devfreq_cooling_get_max_state(struct thermal_cooling_device *cdev,
unsigned long *state)
{
struct devfreq_cooling_device *dfc = cdev->devdata;
*state = dfc->freq_table_size - 1;
return 0;
}
static int devfreq_cooling_get_cur_state(struct thermal_cooling_device *cdev,
unsigned long *state)
{
struct devfreq_cooling_device *dfc = cdev->devdata;
*state = dfc->cooling_state;
return 0;
}
static int devfreq_cooling_set_cur_state(struct thermal_cooling_device *cdev,
unsigned long state)
{
struct devfreq_cooling_device *dfc = cdev->devdata;
struct devfreq *df = dfc->devfreq;
struct device *dev = df->dev.parent;
int ret;
if (state == dfc->cooling_state)
return 0;
dev_dbg(dev, "Setting cooling state %lu\n", state);
if (state >= dfc->freq_table_size)
return -EINVAL;
ret = partition_enable_opps(dfc, state);
if (ret)
return ret;
dfc->cooling_state = state;
return 0;
}
/**
* freq_get_state() - get the cooling state corresponding to a frequency
* @dfc: Pointer to devfreq cooling device
* @freq: frequency in Hz
*
* Return: the cooling state associated with the @freq, or
* THERMAL_CSTATE_INVALID if it wasn't found.
*/
static unsigned long
freq_get_state(struct devfreq_cooling_device *dfc, unsigned long freq)
{
int i;
for (i = 0; i < dfc->freq_table_size; i++) {
if (dfc->freq_table[i] == freq)
return i;
}
return THERMAL_CSTATE_INVALID;
}
static unsigned long get_voltage(struct devfreq *df, unsigned long freq)
{
struct device *dev = df->dev.parent;
unsigned long voltage;
struct dev_pm_opp *opp;
opp = dev_pm_opp_find_freq_exact(dev, freq, true);
if (PTR_ERR(opp) == -ERANGE)
opp = dev_pm_opp_find_freq_exact(dev, freq, false);
if (IS_ERR(opp)) {
dev_err_ratelimited(dev, "Failed to find OPP for frequency %lu: %ld\n",
freq, PTR_ERR(opp));
return 0;
}
voltage = dev_pm_opp_get_voltage(opp) / 1000; /* mV */
dev_pm_opp_put(opp);
if (voltage == 0) {
dev_err_ratelimited(dev,
"Failed to get voltage for frequency %lu\n",
freq);
}
return voltage;
}
/**
* get_static_power() - calculate the static power
* @dfc: Pointer to devfreq cooling device
* @freq: Frequency in Hz
*
* Calculate the static power in milliwatts using the supplied
* get_static_power(). The current voltage is calculated using the
* OPP library. If no get_static_power() was supplied, assume the
* static power is negligible.
*/
static unsigned long
get_static_power(struct devfreq_cooling_device *dfc, unsigned long freq)
{
struct devfreq *df = dfc->devfreq;
unsigned long voltage;
if (!dfc->power_ops->get_static_power)
return 0;
voltage = get_voltage(df, freq);
if (voltage == 0)
return 0;
return dfc->power_ops->get_static_power(df, voltage);
}
/**
* get_dynamic_power - calculate the dynamic power
* @dfc: Pointer to devfreq cooling device
* @freq: Frequency in Hz
* @voltage: Voltage in millivolts
*
* Calculate the dynamic power in milliwatts consumed by the device at
* frequency @freq and voltage @voltage. If the get_dynamic_power()
* was supplied as part of the devfreq_cooling_power struct, then that
* function is used. Otherwise, a simple power model (Pdyn = Coeff *
* Voltage^2 * Frequency) is used.
*/
static unsigned long
get_dynamic_power(struct devfreq_cooling_device *dfc, unsigned long freq,
unsigned long voltage)
{
u64 power;
u32 freq_mhz;
struct devfreq_cooling_power *dfc_power = dfc->power_ops;
if (dfc_power->get_dynamic_power)
return dfc_power->get_dynamic_power(dfc->devfreq, freq,
voltage);
freq_mhz = freq / 1000000;
power = (u64)dfc_power->dyn_power_coeff * freq_mhz * voltage * voltage;
do_div(power, 1000000000);
return power;
}
static inline unsigned long get_total_power(struct devfreq_cooling_device *dfc,
unsigned long freq,
unsigned long voltage)
{
return get_static_power(dfc, freq) + get_dynamic_power(dfc, freq,
voltage);
}
static int devfreq_cooling_get_requested_power(struct thermal_cooling_device *cdev,
struct thermal_zone_device *tz,
u32 *power)
{
struct devfreq_cooling_device *dfc = cdev->devdata;
struct devfreq *df = dfc->devfreq;
struct devfreq_dev_status *status = &df->last_status;
unsigned long state;
unsigned long freq = status->current_frequency;
unsigned long voltage;
u32 dyn_power = 0;
u32 static_power = 0;
int res;
state = freq_get_state(dfc, freq);
if (state == THERMAL_CSTATE_INVALID) {
res = -EAGAIN;
goto fail;
}
if (dfc->power_ops->get_real_power) {
voltage = get_voltage(df, freq);
if (voltage == 0) {
res = -EINVAL;
goto fail;
}
res = dfc->power_ops->get_real_power(df, power, freq, voltage);
if (!res) {
state = dfc->capped_state;
dfc->res_util = dfc->power_table[state];
dfc->res_util *= SCALE_ERROR_MITIGATION;
if (*power > 1)
dfc->res_util /= *power;
} else {
goto fail;
}
} else {
dyn_power = dfc->power_table[state];
/* Scale dynamic power for utilization */
dyn_power *= status->busy_time;
dyn_power /= status->total_time;
/* Get static power */
static_power = get_static_power(dfc, freq);
*power = dyn_power + static_power;
}
trace_thermal_power_devfreq_get_power(cdev, status, freq, dyn_power,
static_power, *power);
return 0;
fail:
/* It is safe to set max in this case */
dfc->res_util = SCALE_ERROR_MITIGATION;
return res;
}
static int devfreq_cooling_state2power(struct thermal_cooling_device *cdev,
struct thermal_zone_device *tz,
unsigned long state,
u32 *power)
{
struct devfreq_cooling_device *dfc = cdev->devdata;
unsigned long freq;
u32 static_power;
if (state >= dfc->freq_table_size)
return -EINVAL;
freq = dfc->freq_table[state];
static_power = get_static_power(dfc, freq);
*power = dfc->power_table[state] + static_power;
return 0;
}
static int devfreq_cooling_power2state(struct thermal_cooling_device *cdev,
struct thermal_zone_device *tz,
u32 power, unsigned long *state)
{
struct devfreq_cooling_device *dfc = cdev->devdata;
struct devfreq *df = dfc->devfreq;
struct devfreq_dev_status *status = &df->last_status;
unsigned long freq = status->current_frequency;
unsigned long busy_time;
s32 dyn_power;
u32 static_power;
s32 est_power;
int i;
if (dfc->power_ops->get_real_power) {
/* Scale for resource utilization */
est_power = power * dfc->res_util;
est_power /= SCALE_ERROR_MITIGATION;
} else {
static_power = get_static_power(dfc, freq);
dyn_power = power - static_power;
dyn_power = dyn_power > 0 ? dyn_power : 0;
/* Scale dynamic power for utilization */
busy_time = status->busy_time ?: 1;
est_power = (dyn_power * status->total_time) / busy_time;
}
/*
* Find the first cooling state that is within the power
* budget for dynamic power.
*/
for (i = 0; i < dfc->freq_table_size - 1; i++)
if (est_power >= dfc->power_table[i])
break;
*state = i;
dfc->capped_state = i;
trace_thermal_power_devfreq_limit(cdev, freq, *state, power);
return 0;
}
static struct thermal_cooling_device_ops devfreq_cooling_ops = {
.get_max_state = devfreq_cooling_get_max_state,
.get_cur_state = devfreq_cooling_get_cur_state,
.set_cur_state = devfreq_cooling_set_cur_state,
};
/**
* devfreq_cooling_gen_tables() - Generate power and freq tables.
* @dfc: Pointer to devfreq cooling device.
*
* Generate power and frequency tables: the power table hold the
* device's maximum power usage at each cooling state (OPP). The
* static and dynamic power using the appropriate voltage and
* frequency for the state, is acquired from the struct
* devfreq_cooling_power, and summed to make the maximum power draw.
*
* The frequency table holds the frequencies in descending order.
* That way its indexed by cooling device state.
*
* The tables are malloced, and pointers put in dfc. They must be
* freed when unregistering the devfreq cooling device.
*
* Return: 0 on success, negative error code on failure.
*/
static int devfreq_cooling_gen_tables(struct devfreq_cooling_device *dfc)
{
struct devfreq *df = dfc->devfreq;
struct device *dev = df->dev.parent;
int ret, num_opps;
unsigned long freq;
u32 *power_table = NULL;
u32 *freq_table;
int i;
num_opps = dev_pm_opp_get_opp_count(dev);
if (dfc->power_ops) {
power_table = kcalloc(num_opps, sizeof(*power_table),
GFP_KERNEL);
if (!power_table)
return -ENOMEM;
}
freq_table = kcalloc(num_opps, sizeof(*freq_table),
GFP_KERNEL);
if (!freq_table) {
ret = -ENOMEM;
goto free_power_table;
}
for (i = 0, freq = ULONG_MAX; i < num_opps; i++, freq--) {
unsigned long power, voltage;
struct dev_pm_opp *opp;
opp = dev_pm_opp_find_freq_floor(dev, &freq);
if (IS_ERR(opp)) {
ret = PTR_ERR(opp);
goto free_tables;
}
voltage = dev_pm_opp_get_voltage(opp) / 1000; /* mV */
dev_pm_opp_put(opp);
if (dfc->power_ops) {
if (dfc->power_ops->get_real_power)
power = get_total_power(dfc, freq, voltage);
else
power = get_dynamic_power(dfc, freq, voltage);
dev_dbg(dev, "Power table: %lu MHz @ %lu mV: %lu = %lu mW\n",
freq / 1000000, voltage, power, power);
power_table[i] = power;
}
freq_table[i] = freq;
}
if (dfc->power_ops)
dfc->power_table = power_table;
dfc->freq_table = freq_table;
dfc->freq_table_size = num_opps;
return 0;
free_tables:
kfree(freq_table);
free_power_table:
kfree(power_table);
return ret;
}
/**
* of_devfreq_cooling_register_power() - Register devfreq cooling device,
* with OF and power information.
* @np: Pointer to OF device_node.
* @df: Pointer to devfreq device.
* @dfc_power: Pointer to devfreq_cooling_power.
*
* Register a devfreq cooling device. The available OPPs must be
* registered on the device.
*
* If @dfc_power is provided, the cooling device is registered with the
* power extensions. For the power extensions to work correctly,
* devfreq should use the simple_ondemand governor, other governors
* are not currently supported.
*/
struct thermal_cooling_device *
of_devfreq_cooling_register_power(struct device_node *np, struct devfreq *df,
struct devfreq_cooling_power *dfc_power)
{
struct thermal_cooling_device *cdev;
struct devfreq_cooling_device *dfc;
char dev_name[THERMAL_NAME_LENGTH];
int err;
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);