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// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright 2021 Linaro Limited
*
* Author: Daniel Lezcano <daniel.lezcano@linaro.org>
*
* The devfreq device combined with the energy model and the load can
* give an estimation of the power consumption as well as limiting the
* power.
*
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/cpumask.h>
#include <linux/devfreq.h>
#include <linux/dtpm.h>
#include <linux/energy_model.h>
#include <linux/of.h>
#include <linux/pm_qos.h>
#include <linux/slab.h>
#include <linux/units.h>
struct dtpm_devfreq {
struct dtpm dtpm;
struct dev_pm_qos_request qos_req;
struct devfreq *devfreq;
};
static struct dtpm_devfreq *to_dtpm_devfreq(struct dtpm *dtpm)
{
return container_of(dtpm, struct dtpm_devfreq, dtpm);
}
static int update_pd_power_uw(struct dtpm *dtpm)
{
struct dtpm_devfreq *dtpm_devfreq = to_dtpm_devfreq(dtpm);
struct devfreq *devfreq = dtpm_devfreq->devfreq;
struct device *dev = devfreq->dev.parent;
struct em_perf_domain *pd = em_pd_get(dev);
dtpm->power_min = pd->table[0].power;
dtpm->power_max = pd->table[pd->nr_perf_states - 1].power;
return 0;
}
static u64 set_pd_power_limit(struct dtpm *dtpm, u64 power_limit)
{
struct dtpm_devfreq *dtpm_devfreq = to_dtpm_devfreq(dtpm);
struct devfreq *devfreq = dtpm_devfreq->devfreq;
struct device *dev = devfreq->dev.parent;
struct em_perf_domain *pd = em_pd_get(dev);
unsigned long freq;
int i;
for (i = 0; i < pd->nr_perf_states; i++) {
if (pd->table[i].power > power_limit)
break;
}
freq = pd->table[i - 1].frequency;
dev_pm_qos_update_request(&dtpm_devfreq->qos_req, freq);
power_limit = pd->table[i - 1].power;
return power_limit;
}
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 u64 get_pd_power_uw(struct dtpm *dtpm)
{
struct dtpm_devfreq *dtpm_devfreq = to_dtpm_devfreq(dtpm);
struct devfreq *devfreq = dtpm_devfreq->devfreq;
struct device *dev = devfreq->dev.parent;
struct em_perf_domain *pd = em_pd_get(dev);
struct devfreq_dev_status status;
unsigned long freq;
u64 power;
int i;
mutex_lock(&devfreq->lock);
status = devfreq->last_status;
mutex_unlock(&devfreq->lock);
freq = DIV_ROUND_UP(status.current_frequency, HZ_PER_KHZ);
_normalize_load(&status);
for (i = 0; i < pd->nr_perf_states; i++) {
if (pd->table[i].frequency < freq)
continue;
power = pd->table[i].power;
power *= status.busy_time;
power >>= 10;
return power;
}
return 0;
}
static void pd_release(struct dtpm *dtpm)
{
struct dtpm_devfreq *dtpm_devfreq = to_dtpm_devfreq(dtpm);
if (dev_pm_qos_request_active(&dtpm_devfreq->qos_req))
dev_pm_qos_remove_request(&dtpm_devfreq->qos_req);
kfree(dtpm_devfreq);
}
static struct dtpm_ops dtpm_ops = {
.set_power_uw = set_pd_power_limit,
.get_power_uw = get_pd_power_uw,
.update_power_uw = update_pd_power_uw,
.release = pd_release,
};
static int __dtpm_devfreq_setup(struct devfreq *devfreq, struct dtpm *parent)
{
struct device *dev = devfreq->dev.parent;
struct dtpm_devfreq *dtpm_devfreq;
struct em_perf_domain *pd;
int ret = -ENOMEM;
pd = em_pd_get(dev);
if (!pd) {
ret = dev_pm_opp_of_register_em(dev, NULL);
if (ret) {
pr_err("No energy model available for '%s'\n", dev_name(dev));
return -EINVAL;
}
}
dtpm_devfreq = kzalloc(sizeof(*dtpm_devfreq), GFP_KERNEL);
if (!dtpm_devfreq)
return -ENOMEM;
dtpm_init(&dtpm_devfreq->dtpm, &dtpm_ops);
dtpm_devfreq->devfreq = devfreq;
ret = dtpm_register(dev_name(dev), &dtpm_devfreq->dtpm, parent);
if (ret) {
pr_err("Failed to register '%s': %d\n", dev_name(dev), ret);
kfree(dtpm_devfreq);
return ret;
}
ret = dev_pm_qos_add_request(dev, &dtpm_devfreq->qos_req,
DEV_PM_QOS_MAX_FREQUENCY,
PM_QOS_MAX_FREQUENCY_DEFAULT_VALUE);
if (ret) {
pr_err("Failed to add QoS request: %d\n", ret);
goto out_dtpm_unregister;
}
dtpm_update_power(&dtpm_devfreq->dtpm);
return 0;
out_dtpm_unregister:
dtpm_unregister(&dtpm_devfreq->dtpm);
return ret;
}
static int dtpm_devfreq_setup(struct dtpm *dtpm, struct device_node *np)
{
struct devfreq *devfreq;
devfreq = devfreq_get_devfreq_by_node(np);
if (IS_ERR(devfreq))
return 0;
return __dtpm_devfreq_setup(devfreq, dtpm);
}
struct dtpm_subsys_ops dtpm_devfreq_ops = {
.name = KBUILD_MODNAME,
.setup = dtpm_devfreq_setup,
};
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