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Release 4.14 drivers/devfreq/exynos-bus.c

Directory: drivers/devfreq
/*
 * 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; }

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/* * 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 */ new_opp = devfreq_recommended_opp(dev, freq, flags); if (IS_ERR(new_opp)) { dev_err(dev, "failed to get recommended opp instance\n"); return PTR_ERR(new_opp); } new_freq = dev_pm_opp_get_freq(new_opp); new_volt = dev_pm_opp_get_voltage(new_opp); dev_pm_opp_put(new_opp); old_freq = bus->curr_freq; 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 (%luHz -> %luHz, %luHz)\n", old_freq, new_freq, clk_get_rate(bus->clk)); out: mutex_unlock(&bus->lock); return ret; }

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Viresh Kumar82.73%250.00%
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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; }

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Chanwoo Choi14099.29%150.00%
Viresh Kumar10.71%150.00%
Total141100.00%2100.00%


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); }

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/* * 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 */ new_opp = devfreq_recommended_opp(dev, freq, flags); if (IS_ERR(new_opp)) { dev_err(dev, "failed to get recommended opp instance\n"); return PTR_ERR(new_opp); } new_freq = dev_pm_opp_get_freq(new_opp); dev_pm_opp_put(new_opp); old_freq = bus->curr_freq; 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 (%luHz -> %luHz, %luHz)\n", old_freq, new_freq, clk_get_rate(bus->clk)); out: mutex_unlock(&bus->lock); return ret; }

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Chanwoo Choi17895.70%360.00%
Viresh Kumar84.30%240.00%
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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); }

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Chanwoo Choi33100.00%2100.00%
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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; }

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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); opp = devfreq_recommended_opp(dev, &rate, 0); if (IS_ERR(opp)) { dev_err(dev, "failed to find dev_pm_opp\n"); ret = PTR_ERR(opp); goto err_opp; } bus->curr_freq = dev_pm_opp_get_freq(opp); dev_pm_opp_put(opp); return 0; err_opp: dev_pm_opp_of_remove_table(dev); err_clk: clk_disable_unprepare(bus->clk); return ret; }

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Chanwoo Choi19090.05%250.00%
Viresh Kumar219.95%250.00%
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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; }

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Chanwoo Choi61596.39%350.00%
Peter Chen182.82%116.67%
Bartlomiej Zolnierkiewicz30.47%116.67%
MyungJoo Ham20.31%116.67%
Total638100.00%6100.00%

#ifdef CONFIG_PM_SLEEP
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; }

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Chanwoo Choi52100.00%1100.00%
Total52100.00%1100.00%


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; }

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#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");

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Chanwoo Choi224797.23%444.44%
Viresh Kumar411.77%222.22%
Peter Chen180.78%111.11%
Bartlomiej Zolnierkiewicz30.13%111.11%
MyungJoo Ham20.09%111.11%
Total2311100.00%9100.00%
Directory: drivers/devfreq
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