diff options
Diffstat (limited to 'drivers/devfreq/exynos-bus.c')
| -rw-r--r-- | drivers/devfreq/exynos-bus.c | 570 |
1 files changed, 570 insertions, 0 deletions
diff --git a/drivers/devfreq/exynos-bus.c b/drivers/devfreq/exynos-bus.c new file mode 100644 index 000000000000..2363d0a189b7 --- /dev/null +++ b/drivers/devfreq/exynos-bus.c @@ -0,0 +1,570 @@ +/* + * 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; + + struct dev_pm_opp *curr_opp; + + 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, old_volt, 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 = dev_pm_opp_get_freq(bus->curr_opp); + old_volt = dev_pm_opp_get_voltage(bus->curr_opp); + 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_opp = new_opp; + + 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; + + rcu_read_lock(); + stat->current_frequency = dev_pm_opp_get_freq(bus->curr_opp); + rcu_read_unlock(); + + 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 = dev_pm_opp_get_freq(bus->curr_opp); + 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_opp = new_opp; + + 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; + 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 */ + rcu_read_lock(); + ret = dev_pm_opp_of_add_table(dev); + if (ret < 0) { + dev_err(dev, "failed to get OPP table\n"); + rcu_read_unlock(); + goto err_clk; + } + + rate = clk_get_rate(bus->clk); + bus->curr_opp = devfreq_recommended_opp(dev, &rate, 0); + if (IS_ERR(bus->curr_opp)) { + dev_err(dev, "failed to find dev_pm_opp\n"); + rcu_read_unlock(); + ret = PTR_ERR(bus->curr_opp); + goto err_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; + 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) + goto err; + + profile = devm_kzalloc(dev, sizeof(*profile), GFP_KERNEL); + if (!profile) { + ret = -ENOMEM; + goto err; + } + + if (of_parse_phandle(dev->of_node, "devfreq", 0)) + 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 = -EPROBE_DEFER; + 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 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; +} + +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"); |