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path: root/kernel/stop_machine.c

Age	Commit message (Expand)	Author
2011-11-06	Merge branch 'modsplit-Oct31_2011' of git://git.kernel.org/pub/scm/linux/kern...	Linus Torvalds
2011-10-31	stop_machine: make stop_machine safe and efficient to call early	Jeremy Fitzhardinge
2011-10-31	kernel: Map most files to use export.h instead of module.h	Paul Gortmaker
2011-07-26	atomic: use <linux/atomic.h>	Arun Sharma
2011-06-27	x86, mtrr: use stop_machine APIs for doing MTRR rendezvous	Suresh Siddha
2011-06-27	stop_machine: implement stop_machine_from_inactive_cpu()	Tejun Heo
2011-06-27	stop_machine: reorganize stop_cpus() implementation	Tejun Heo
2011-06-27	x86, mtrr: lock stop machine during MTRR rendezvous sequence	Suresh Siddha
2011-03-22	kthread: use kthread_create_on_node()	Eric Dumazet
2010-10-26	stop_machine: convert cpu notifier to return encapsulate errno value	Akinobu Mita
2010-10-26	kernel/stop_machine.c: fix unused variable warning	Rakib Mullick
2010-10-18	sched: Create special class for stop/migrate work	Peter Zijlstra
2010-08-09	stop_machine: struct cpu_stopper, remove alignment padding on 64 bits	Richard Kennedy
2010-05-31	sched: Make sure timers have migrated before killing the migration_thread	Amit K. Arora
2010-05-18	stop_machine: Move local variable closer to the usage site in cpu_stop_cpu_ca...	Ingo Molnar
2010-05-08	cpu_stop: add dummy implementation for UP	Tejun Heo
2010-05-06	sched: replace migration_thread with cpu_stop	Tejun Heo
2010-05-06	stop_machine: reimplement using cpu_stop	Tejun Heo
2010-05-06	cpu_stop: implement stop_cpu[s]()	Tejun Heo
2010-02-17	percpu: add __percpu sparse annotations to core kernel subsystems	Tejun Heo
2009-03-30	cpumask: remove cpumask_t from core	Rusty Russell
2009-02-20	alloc_percpu: change percpu_ptr to per_cpu_ptr	Rusty Russell
2009-01-05	stop_machine: introduce stop_machine_create/destroy.	Heiko Carstens
2009-01-01	cpumask: convert rest of files in kernel/	Rusty Russell
2008-11-16	stop_machine: fix race with return value (fixes Bug #11989)	Rusty Russell
2008-10-25	Revert "Call init_workqueues before pre smp initcalls."	Linus Torvalds
2008-10-22	stop_machine: fix error code handling on multiple cpus	Heiko Carstens
2008-10-22	stop_machine: use workqueues instead of kernel threads	Heiko Carstens
2008-08-12	stop_machine: remove unused variable	Li Zefan
2008-07-28	stop_machine(): stop_machine_run() changed to use cpu mask	Rusty Russell
2008-07-28	Simplify stop_machine	Rusty Russell
2008-07-28	stop_machine: add ALL_CPUS option	Jason Baron
2008-07-18	cpumask: Replace cpumask_of_cpu with cpumask_of_cpu_ptr	Mike Travis
2008-06-23	sched: add new API sched_setscheduler_nocheck: add a flag to control access c...	Rusty Russell
2008-05-23	stop_machine: make stop_machine_run more virtualization friendly	Christian Borntraeger
2008-04-21	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/juh...	Linus Torvalds
2008-04-21	Merge branch 'semaphore' of git://git.kernel.org/pub/scm/linux/kernel/git/wil...	Linus Torvalds
2008-04-21	trivial: small cleanups	Pavel Machek
2008-04-19	generic: use new set_cpus_allowed_ptr function	Mike Travis
2008-04-18	kernel: Remove unnecessary inclusions of asm/semaphore.h	Matthew Wilcox
2008-02-06	stopmachine: semaphore to mutex	Daniel Walker
2008-01-25	cpu-hotplug: replace lock_cpu_hotplug() with get_online_cpus()	Gautham R Shenoy
2007-07-16	Fix stop_machine_run problem with naughty real time process	Satoru Takeuchi
2007-05-11	stop_machine() now uses hard_irq_disable	Benjamin Herrenschmidt
2007-05-08	Use stop_machine_run in the Intel RNG driver	Prarit Bhargava
2006-09-29	[PATCH] stop_machine.c copyright	Rusty Russell
2006-08-27	[PATCH] Remove redundant up() in stop_machine()	Yingchao Zhou
2006-07-03	[PATCH] revert "kthread: convert stop_machine into a kthread"	Andrew Morton
2006-06-25	[PATCH] kthread: convert stop_machine into a kthread	Serge E. Hallyn
2006-01-10	[PATCH] Remove set_fs() in stop_machine()	akpm@osdl.org

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generated by cgit v1.2.3 (git 2.25.1) at 2024-09-10 15:49:06 +0000

// SPDX-License-Identifier: GPL-2.0-only
/*
 * 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.
 */

#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 */
	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;
}

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 */
	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;
}

static void<