/*
* Generic Exynos Bus frequency driver with DEVFREQ Framework
*
* Copyright (c) 2016 Samsung Electronics Co., Ltd.
* Author : Chanwoo Choi <cw00.choi@samsung.com>
*
* This driver support Exynos Bus frequency feature by using
* DEVFREQ framework and is based on drivers/devfreq/exynos/exynos4_bus.c.
*
* 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.
*/
#include <linux/clk.h>
#include <linux/devfreq.h>
#include <linux/devfreq-event.h>
#include <linux/device.h>
#include <linux/export.h>
#include <linux/module.h>
#include <linux/of_device.h>
#include <linux/pm_opp.h>
#include <linux/platform_device.h>
#include <linux/regulator/consumer.h>
#include <linux/slab.h>
#define DEFAULT_SATURATION_RATIO 40
#define DEFAULT_VOLTAGE_TOLERANCE 2
struct exynos_bus {
struct device *dev;
struct devfreq *devfreq;
struct devfreq_event_dev **edev;
unsigned int edev_count;
struct mutex lock;
unsigned long curr_freq;
struct regulator *regulator;
struct clk *clk;
unsigned int voltage_tolerance;
unsigned int ratio;
};
/*
* Control the devfreq-event device to get the current state of bus
*/
#define exynos_bus_ops_edev(ops) \
static int exynos_bus_##ops(struct exynos_bus *bus) \
{ \
int i, ret; \
\
for (i = 0; i < bus->edev_count; i++) { \
if (!bus->edev[i]) \
continue; \
ret = devfreq_event_##ops(bus->edev[i]); \
if (ret < 0) \
return ret; \
} \
\
return 0; \
}
exynos_bus_ops_edev(enable_edev);
exynos_bus_ops_edev(disable_edev);
exynos_bus_ops_edev(set_event);
static int exynos_bus_get_event(struct exynos_bus *bus,
struct devfreq_event_data *edata)
{
struct devfreq_event_data event_data;
unsigned long load_count = 0, total_count = 0;
int i, ret = 0;
for (i = 0; i < bus->edev_count; i++) {
if (!bus->edev[i])
continue;
ret = devfreq_event_get_event(bus->edev[i], &event_data);
if (ret < 0)
return ret;
if (i == 0 || event_data.load_count > load_count) {
load_count = event_data.load_count;
total_count = event_data.total_count;
}
}
edata->load_count = load_count;
edata->total_count = total_count;
return ret;
}
/*
* Must necessary function for devfreq simple-ondemand governor
*/
static int exynos_bus_target(struct device *dev, unsigned long *freq, u32 flags)
{
struct exynos_bus *bus = dev_get_drvdata(dev);
struct dev_pm_opp *new_opp;
unsigned long old_freq, new_freq, new_volt, tol;
int ret = 0;
/* Get new opp-bus instance according to new bus clock */
rcu_read_lock();
new_opp = devfreq_recommended_opp(dev, freq, flags);
if (IS_ERR(new_opp)) {
dev_err(dev, "failed to get recommended opp instance\n");
rcu_read_unlock();
return PTR_ERR(new_opp);
}
new_freq = dev_pm_opp_get_freq(new_opp);
new_volt = dev_pm_opp_get_voltage(new_opp);
old_freq = bus->curr_freq;
rcu_read_unlock();
if (old_freq == new_freq)
return 0;
tol = new_volt * bus->voltage_tolerance / 100;
/* Change voltage and frequency according to new OPP level */
mutex_lock(&bus->lock);
if (old_freq < new_freq) {
ret = regulator_set_voltage_tol(bus->regulator, new_volt, tol);
if (ret < 0) {
dev_err(bus->dev, "failed to set voltage\n");
goto out;
}
}
ret = clk_set_rate(bus->clk, new_freq);
if (ret < 0) {
dev_err(dev, "failed to change clock of bus\n");
clk_set_rate(bus->clk, old_freq);
goto out;
}
if (old_freq > new_freq) {
ret = regulator_set_voltage_tol(bus->regulator, new_volt, tol);
if (ret < 0) {
dev_err(bus->dev, "failed to set voltage\n");
goto out;
}
}
bus->curr_freq = new_freq;
dev_dbg(dev, "Set the frequency of bus (%lukHz -> %lukHz)\n",
old_freq/1000, new_freq/1000);
out:
mutex_unlock(&bus->lock);
return ret;
}
static int exynos_bus_get_dev_status(struct device *dev,
struct devfreq_dev_status *stat)
{
struct exynos_bus *bus = dev_get_drvdata(dev);
struct devfreq_event_data edata;
int ret;
stat->current_frequency = bus->curr_freq;
ret = exynos_bus_get_event(bus, &edata);
if (ret < 0) {
stat->total_time = stat->busy_time = 0;
goto err;
}
stat->busy_time = (edata.load_count * 100) / bus->ratio;
stat->total_time = edata.total_count;
dev_dbg(dev, "Usage of devfreq-event : %lu/%lu\n", stat->busy_time,
stat->total_time);
err:
ret = exynos_bus_set_event(bus);
if (ret < 0) {
dev_err(dev, "failed to set event to devfreq-event devices\n");
return ret;
}
return ret;
}
static void exynos_bus_exit(struct device *dev)
{
struct exynos_bus *bus = dev_get_drvdata(dev);
int ret;
ret = exynos_bus_disable_edev(bus);
if (ret < 0)
dev_warn(dev, "failed to disable the devfreq-event devices\n");
if (bus->regulator)
regulator_disable(bus->regulator);
dev_pm_opp_of_remove_table(dev);
clk_disable_unprepare(bus->clk);
}
/*
* Must necessary function for devfreq passive governor
*/
static int exynos_bus_passive_target(struct device *dev, unsigned long *freq,
u32 flags)
{
struct exynos_bus *bus = dev_get_drvdata(dev);
struct dev_pm_opp *new_opp;
unsigned long old_freq, new_freq;
int ret = 0;
/* Get new opp-bus instance according to new bus clock */
rcu_read_lock();
new_opp = devfreq_recommended_opp(dev, freq, flags);
if (IS_ERR(new_opp)) {
dev_err(dev, "failed to get recommended opp instance\n");
rcu_read_unlock();
return PTR_ERR(new_opp);
}
new_freq = dev_pm_opp_get_freq(new_opp);
old_freq = bus->curr_freq;
rcu_read_unlock();
if (old_freq == new_freq)
return 0;
/* Change the frequency according to new OPP level */
mutex_lock(&bus->lock);
ret = clk_set_rate(bus->clk, new_freq);
if (ret < 0) {
dev_err(dev, "failed to set the clock of bus\n");
goto out;
}
*freq = new_freq;
bus->curr_freq = new_freq;
dev_dbg(dev, "Set the frequency of bus (%lukHz -> %lukHz)\n",
old_freq/1000, new_freq/1000);
out:
mutex_unlock(&bus->lock);
return ret;
}
static void exynos_bus_passive_exit(struct device *dev)
{
struct exynos_bus *bus = dev_get_drvdata(dev);
dev_pm_opp_of_remove_table(dev);
clk_disable_unprepare(bus->clk);
}
static int exynos_bus_parent_parse_of(struct device_node *np,
struct exynos_bus *bus)
{
struct device *dev = bus->dev;
int i, ret, count, size;
/* Get the regulator to provide each bus with the power */
bus->regulator = devm_regulator_get(dev, "vdd");
if (IS_ERR(bus->regulator)) {
dev_err(dev, "failed to get VDD regulator\n");
return PTR_ERR(bus->regulator);
}
ret = regulator_enable(bus->regulator);
if (ret < 0) {
dev_err(dev, "failed to enable VDD regulator\n");
return ret;
}
/*
* Get the devfreq-event devices to get the current utilization of
* buses. This raw data will be used in devfreq ondemand governor.
*/
count = devfreq_event_get_edev_count(dev);
if (count < 0) {
dev_err(dev, "failed to get the count of devfreq-event dev\n");
ret = count;
goto err_regulator;
}
bus->edev_count = count;
size = sizeof(*bus->edev) * count;
bus->edev = devm_kzalloc(dev, size, GFP_KERNEL);
if (!bus->edev) {
ret = -ENOMEM;
goto err_regulator;
}
for (i = 0; i < count; i++) {
bus->edev[i] = devfreq_event_get_edev_by_phandle(dev, i);
if (IS_ERR(bus->edev[i])) {
ret = -EPROBE_DEFER;
goto err_regulator;
}
}
/*
* Optionally, Get the saturation ratio according to Exynos SoC
* When measuring the utilization of each AXI bus with devfreq-event
* devices, the measured real cycle might be much lower than the
* total cycle of bus during sampling rate. In result, the devfreq
* simple-ondemand governor might not decide to change the current
* frequency due to too utilization (= real cycle/total cycle).
* So, this property is used to adjust the utilization when calculating
* the busy_time in exynos_bus_get_dev_status().
*/
if (of_property_read_u32(np, "exynos,saturation-ratio", &bus->ratio))
bus->ratio = DEFAULT_SATURATION_RATIO;
if (of_property_read_u32(np, "exynos,voltage-tolerance",
&bus->voltage_tolerance))
bus->voltage_tolerance = DEFAULT_VOLTAGE_TOLERANCE;
return 0;
err_regulator:
regulator_disable(bus->regulator);
return ret;
}
static int exynos_bus_parse_of(struct device_node *np,
struct exynos_bus *bus)
{
struct device *dev = bus->dev;
struct dev_pm_opp *opp;
unsigned long rate;
int ret;
/* Get the clock to provide each bus with source clock */
bus->clk = devm_clk_get(dev, "bus");
if (IS_ERR(bus->clk)) {
dev_err(dev, "failed to get bus clock\n");
return PTR_ERR(bus->clk);
}
ret = clk_prepare_enable(bus->clk);
if (ret < 0) {
dev_err(dev, "failed to get enable clock\n");
return ret;
}
/* Get the freq and voltage from OPP table to scale the bus freq */
ret = dev_pm_opp_of_add_table(dev);
if (ret < 0) {
dev_err(dev, "failed to get OPP table\n");
goto err_clk;
}
rate = clk_get_rate(bus->clk);
rcu_read_lock();
opp = devfreq_recommended_opp(dev, &rate, 0);
if (IS_ERR(opp)) {
dev_err(dev, "failed to find dev_pm_opp\n");
rcu_read_unlock();
ret = PTR_ERR(opp);
goto err_opp;
}
bus->curr_freq = dev_pm_opp_get_freq(opp);
rcu_read_unlock();
return 0;
err_opp:
dev_pm_opp_of_remove_table(dev);
err_clk:
clk_disable_unprepare(bus->clk);
return ret;
}
static int exynos_bus_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct device_node *np = dev->of_node, *node;
struct devfreq_dev_profile *profile;
struct devfreq_simple_ondemand_data *ondemand_data;
struct devfreq_passive_data *passive_data;
struct devfreq *parent_devfreq;
struct exynos_bus *bus;
int ret, max_state;
unsigned long min_freq, max_freq;
if (!np) {
dev_err(dev, "failed to find devicetree node\n");
return -EINVAL;
}
bus = devm_kzalloc(&pdev->dev, sizeof(*bus), GFP_KERNEL);
if (!bus)
return -ENOMEM;
mutex_init(&bus->lock);
bus->dev = &pdev->dev;
platform_set_drvdata(pdev, bus);
/* Parse the device-tree to get the resource information */
ret = exynos_bus_parse_of(np, bus);
if (ret < 0)
return ret;
profile = devm_kzalloc(dev, sizeof(*profile), GFP_KERNEL);
if (!profile) {
ret = -ENOMEM;
goto err;
}
node = of_parse_phandle(dev->of_node, "devfreq", 0);
if (node) {
of_node_put(node);
goto passive;
} else {
ret = exynos_bus_parent_parse_of(np, bus);
}
if (ret < 0)
goto err;
/* Initialize the struct profile and governor data for parent device */
profile->polling_ms = 50;
profile->target = exynos_bus_target;
profile->get_dev_status = exynos_bus_get_dev_status;
profile->exit = exynos_bus_exit;
ondemand_data = devm_kzalloc(dev, sizeof(*ondemand_data), GFP_KERNEL);
if (!ondemand_data) {
ret = -ENOMEM;
goto err;
}
ondemand_data->upthreshold = 40;
ondemand_data->downdifferential = 5;
/* Add devfreq device to monitor and handle the exynos bus */
bus->devfreq = devm_devfreq_add_device(dev, profile, "simple_ondemand",
ondemand_data);
if (IS_ERR(bus->devfreq)) {
dev_err(dev, "failed to add devfreq device\n");
ret = PTR_ERR(bus->devfreq);
goto err;
}
/* Register opp_notifier to catch the change of OPP */
ret = devm_devfreq_register_opp_notifier(dev, bus->devfreq);
if (ret < 0) {
dev_err(dev, "failed to register opp notifier\n");
goto err;
}
/*
* Enable devfreq-event to get raw data which is used to determine
* current bus load.
*/
ret = exynos_bus_enable_edev(bus);
if (ret < 0) {
dev_err(dev, "failed to enable devfreq-event devices\n");
goto err;
}
ret = exynos_bus_set_event(bus);
if (ret < 0) {
dev_err(dev, "failed to set event to devfreq-event devices\n");
goto err;
}
goto out;
passive:
/* Initialize the struct profile and governor data for passive device */
profile->target = exynos_bus_passive_target;
profile->exit = exynos_bus_passive_exit;
/* Get the instance of parent devfreq device */
parent_devfreq = devfreq_get_devfreq_by_phandle(dev, 0);
if (IS_ERR(parent_devfreq)) {
ret = -EPROBE_DEFER;
goto err;
}
passive_data = devm_kzalloc(dev, sizeof(*passive_data), GFP_KERNEL);
if (!passive_data) {
ret = -ENOMEM;
goto err;
}
passive_data->parent = parent_devfreq;
/* Add devfreq device for exynos bus with passive governor */
bus->devfreq = devm_devfreq_add_device(dev, profile, "passive",
passive_data);
if (IS_ERR(bus->devfreq)) {
dev_err(dev,
"failed to add devfreq dev with passive governor\n");
ret = PTR_ERR(bus->devfreq);
goto err;
}
out:
max_state = bus->devfreq->profile->max_state;
min_freq = (bus->devfreq->profile->freq_table[0] / 1000);
max_freq = (bus->devfreq->profile->freq_table[max_state - 1] / 1000);
pr_info("exynos-bus: new bus device registered: %s (%6ld KHz ~ %6ld KHz)\n",
dev_name(dev), min_freq, max_freq);
return 0;
err:
dev_pm_opp_of_remove_table(dev);
clk_disable_unprepare(bus->clk);
return ret;
}
#ifdef [31mCONFIG_PM_SLEEP[0m
static int exynos_bus_resume(struct device *dev)
{
struct exynos_bus *bus = dev_get_drvdata(dev);
int ret;
ret = exynos_bus_enable_edev(bus);
if (ret < 0) {
dev_err(dev, "failed to enable the devfreq-event devices\n");
return ret;
}
return 0;
}
static int exynos_bus_suspend(struct device *dev)
{
struct exynos_bus *bus = dev_get_drvdata(dev);
int ret;
ret = exynos_bus_disable_edev(bus);
if (ret < 0) {
dev_err(dev, "failed to disable the devfreq-event devices\n");
return ret;
}
return 0;
}
#endif
static const struct dev_pm_ops exynos_bus_pm = {
SET_SYSTEM_SLEEP_PM_OPS(exynos_bus_suspend, exynos_bus_resume)
};
static const struct of_device_id exynos_bus_of_match[] = {
{ .compatible = "samsung,exynos-bus", },
{ /* sentinel */ },
};
MODULE_DEVICE_TABLE(of, exynos_bus_of_match);
static struct platform_driver exynos_bus_platdrv = {
.probe = exynos_bus_probe,
.driver = {
.name = "exynos-bus",
.pm = &exynos_bus_pm,
.of_match_table = of_match_ptr(exynos_bus_of_match),
},
};
module_platform_driver(exynos_bus_platdrv);
MODULE_DESCRIPTION("Generic Exynos Bus frequency driver");
MODULE_AUTHOR("Chanwoo Choi <cw00.choi@samsung.com>");
MODULE_LICENSE("GPL v2");