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/* linux/arch/arm/mach-s5pv310/pm-hotplug.c
*
* Copyright (c) 2010 Samsung Electronics Co., Ltd.
* http://www.samsung.com/
*
* S5PV310 - Dynamic CPU hotpluging
*
* 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/init.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/ioport.h>
#include <linux/delay.h>
#include <linux/serial_core.h>
#include <linux/io.h>
#include <linux/platform_device.h>
#include <linux/cpu.h>
#include <linux/percpu.h>
#include <linux/ktime.h>
#include <linux/tick.h>
#include <linux/kernel_stat.h>
#include <linux/sched.h>
#include <linux/suspend.h>
#include <linux/reboot.h>
#include <plat/map-base.h>
#include <plat/gpio-cfg.h>
#include <mach/regs-gpio.h>
#include <mach/regs-irq.h>
#include <linux/gpio.h>
#include <linux/cpufreq.h>
#define CPUMON 1
#define CHECK_DELAY (.5*HZ)
#define TRANS_LOAD_L 20
#define TRANS_LOAD_H 50
#define HOTPLUG_UNLOCKED 0
#define HOTPLUG_LOCKED 1
static struct workqueue_struct *hotplug_wq;
static struct delayed_work hotplug_work;
static unsigned int hotpluging_rate = CHECK_DELAY;
module_param_named(rate, hotpluging_rate, uint, 0644);
static unsigned int user_lock;
module_param_named(lock, user_lock, uint, 0644);
static unsigned int trans_load_l = TRANS_LOAD_L;
module_param_named(loadl, trans_load_l, uint, 0644);
static unsigned int trans_load_h = TRANS_LOAD_H;
module_param_named(loadh, trans_load_h, uint, 0644);
struct cpu_time_info {
cputime64_t prev_cpu_idle;
cputime64_t prev_cpu_wall;
unsigned int load;
};
static DEFINE_PER_CPU(struct cpu_time_info, hotplug_cpu_time);
/* mutex can be used since hotplug_timer does not run in
timer(softirq) context but in process context */
static DEFINE_MUTEX(hotplug_lock);
static void hotplug_timer(struct work_struct *work)
{
unsigned int i, avg_load = 0, load = 0;
unsigned int cur_freq;
mutex_lock(&hotplug_lock);
if (user_lock == 1)
goto no_hotplug;
for_each_online_cpu(i) {
struct cpu_time_info *tmp_info;
cputime64_t cur_wall_time, cur_idle_time;
unsigned int idle_time, wall_time;
tmp_info = &per_cpu(hotplug_cpu_time, i);
cur_idle_time = get_cpu_idle_time_us(i, &cur_wall_time);
idle_time = (unsigned int)cputime64_sub(cur_idle_time,
tmp_info->prev_cpu_idle);
tmp_info->prev_cpu_idle = cur_idle_time;
wall_time = (unsigned int)cputime64_sub(cur_wall_time,
tmp_info->prev_cpu_wall);
tmp_info->prev_cpu_wall = cur_wall_time;
if (wall_time < idle_time)
goto no_hotplug;
tmp_info->load = 100 * (wall_time - idle_time) / wall_time;
load += tmp_info->load;
}
avg_load = load / num_online_cpus();
cur_freq = cpufreq_get(0);
if (((avg_load < trans_load_l) || (cur_freq <= 200 * 1000)) &&
(cpu_online(1) == 1)) {
printk(KERN_INFO "cpu1 turning off!\n");
cpu_down(1);
#if CPUMON
printk(KERN_ERR "CPUMON D %d\n", avg_load);
#endif
printk(KERN_INFO "cpu1 off end!\n");
hotpluging_rate = CHECK_DELAY;
} else if (((avg_load > trans_load_h) && (cur_freq > 200 * 1000)) &&
(cpu_online(1) == 0)) {
printk(KERN_INFO "cpu1 turning on!\n");
cpu_up(1);
#if CPUMON
printk(KERN_ERR "CPUMON U %d\n", avg_load);
#endif
printk(KERN_INFO "cpu1 on end!\n");
hotpluging_rate = CHECK_DELAY * 4;
}
no_hotplug:
queue_delayed_work_on(0, hotplug_wq, &hotplug_work, hotpluging_rate);
mutex_unlock(&hotplug_lock);
}
static int exynos4_pm_hotplug_notifier_event(struct notifier_block *this,
unsigned long event, void *ptr)
{
static unsigned user_lock_saved;
switch (event) {
case PM_SUSPEND_PREPARE:
mutex_lock(&hotplug_lock);
user_lock_saved = user_lock;
user_lock = 1;
pr_info("%s: saving pm_hotplug lock %x\n",
__func__, user_lock_saved);
mutex_unlock(&hotplug_lock);
return NOTIFY_OK;
case PM_POST_RESTORE:
case PM_POST_SUSPEND:
mutex_lock(&hotplug_lock);
pr_info("%s: restoring pm_hotplug lock %x\n",
__func__, user_lock_saved);
user_lock = user_lock_saved;
mutex_unlock(&hotplug_lock);
return NOTIFY_OK;
}
return NOTIFY_DONE;
}
static struct notifier_block exynos4_pm_hotplug_notifier = {
.notifier_call = exynos4_pm_hotplug_notifier_event,
};
static int hotplug_reboot_notifier_call(struct notifier_block *this,
unsigned long code, void *_cmd)
{
mutex_lock(&hotplug_lock);
pr_err("%s: disabling pm hotplug\n", __func__);
user_lock = 1;
mutex_unlock(&hotplug_lock);
return NOTIFY_DONE;
}
static struct notifier_block hotplug_reboot_notifier = {
.notifier_call = hotplug_reboot_notifier_call,
};
static int __init exynos4_pm_hotplug_init(void)
{
printk(KERN_INFO "EXYNOS4 PM-hotplug init function\n");
/* hotplug_wq = create_workqueue("dynamic hotplug"); */
hotplug_wq = alloc_workqueue("dynamic hotplug", 0, 0);
if (!hotplug_wq) {
printk(KERN_ERR "Creation of hotplug work failed\n");
return -EFAULT;
}
INIT_DELAYED_WORK(&hotplug_work, hotplug_timer);
queue_delayed_work_on(0, hotplug_wq, &hotplug_work, 60 * HZ);
register_pm_notifier(&exynos4_pm_hotplug_notifier);
register_reboot_notifier(&hotplug_reboot_notifier);
return 0;
}
late_initcall(exynos4_pm_hotplug_init);
static struct platform_device exynos4_pm_hotplug_device = {
.name = "exynos4-dynamic-cpu-hotplug",
.id = -1,
};
static int __init exynos4_pm_hotplug_device_init(void)
{
int ret;
ret = platform_device_register(&exynos4_pm_hotplug_device);
if (ret) {
printk(KERN_ERR "failed at(%d)\n", __LINE__);
return ret;
}
printk(KERN_INFO "exynos4_pm_hotplug_device_init: %d\n", ret);
return ret;
}
late_initcall(exynos4_pm_hotplug_device_init);
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