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