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/*
* arch/arm/mach-tegra/cpu-tegra3.c
*
* CPU auto-hotplug for Tegra3 CPUs
*
* Copyright (c) 2011, NVIDIA Corporation.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/sched.h>
#include <linux/cpufreq.h>
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/cpu.h>
#include "pm.h"
#define INITIAL_STATE TEGRA_HP_DISABLED
#define IDLE_HYSTERESIS 100000
#define UP_DELAY_MS 1000
#define DOWN_DELAY_MS 2000
static DEFINE_MUTEX(tegra_hp_lock);
static struct workqueue_struct *hotplug_wq;
static struct delayed_work hotplug_work;
static unsigned long up_delay;
static unsigned long down_delay;
module_param(up_delay, ulong, 0644);
module_param(down_delay, ulong, 0644);
static unsigned int idle_top_freq;
static unsigned int idle_bottom_freq;
module_param(idle_top_freq, uint, 0644);
module_param(idle_bottom_freq, uint, 0644);
static unsigned int lpcpu_max_freq;
enum {
TEGRA_HP_DISABLED = 0,
TEGRA_HP_IDLE,
TEGRA_HP_DOWN,
TEGRA_HP_UP,
};
static int hp_state;
static int hp_state_set(const char *arg, const struct kernel_param *kp)
{
int ret = 0;
int old_state;
mutex_lock(&tegra_hp_lock);
old_state = hp_state;
ret = param_set_int(arg, kp);
if (ret == 0) {
switch (hp_state) {
case TEGRA_HP_DISABLED:
if (old_state != TEGRA_HP_DISABLED)
pr_info("Tegra auto-hotplug disabled\n");
break;
case TEGRA_HP_IDLE:
case TEGRA_HP_DOWN:
case TEGRA_HP_UP:
if (old_state == TEGRA_HP_DISABLED) {
queue_delayed_work(
hotplug_wq, &hotplug_work, up_delay);
pr_info("Tegra auto-hotplug enabled\n");
}
break;
default:
pr_warn("%s: unable to set tegra hotplug state %d\n",
__func__, hp_state);
hp_state = old_state;
}
}
mutex_unlock(&tegra_hp_lock);
return ret;
}
static int hp_state_get(char *buffer, const struct kernel_param *kp)
{
return param_get_int(buffer, kp);
}
static struct kernel_param_ops tegra_hp_state_ops = {
.set = hp_state_set,
.get = hp_state_get,
};
module_param_cb(auto_hotplug, &tegra_hp_state_ops, &hp_state, 0644);
static void tegra_auto_hotplug_work_func(struct work_struct *work)
{
bool up = false;
unsigned int cpu = nr_cpu_ids;
mutex_lock(&tegra_hp_lock);
if (is_lp_cluster()) {
mutex_unlock(&tegra_hp_lock);
return;
}
switch (hp_state) {
case TEGRA_HP_DISABLED:
case TEGRA_HP_IDLE:
break;
case TEGRA_HP_DOWN:
cpu = cpumask_next(0, cpu_online_mask);
if (cpu < nr_cpu_ids) {
up = false;
queue_delayed_work(
hotplug_wq, &hotplug_work, down_delay);
}
else
tegra_cluster_control(0, TEGRA_POWER_CLUSTER_LP |
TEGRA_POWER_CLUSTER_IMMEDIATE);
break;
case TEGRA_HP_UP:
cpu = cpumask_next_zero(0, cpu_online_mask);
if (cpu < nr_cpu_ids) {
up = true;
queue_delayed_work(
hotplug_wq, &hotplug_work, up_delay);
}
break;
default:
pr_err("%s: invalid tegra hotplug state %d\n",
__func__, hp_state);
}
mutex_unlock(&tegra_hp_lock);
if (cpu < nr_cpu_ids) {
if (up)
cpu_up(cpu);
else
cpu_down(cpu);
}
}
void tegra_auto_hotplug_governor(unsigned int cpu_freq)
{
mutex_lock(&tegra_hp_lock);
if (is_lp_cluster() && (cpu_freq > lpcpu_max_freq)) {
tegra_cluster_control(0, TEGRA_POWER_CLUSTER_G |
TEGRA_POWER_CLUSTER_IMMEDIATE);
}
switch (hp_state) {
case TEGRA_HP_DISABLED:
break;
case TEGRA_HP_IDLE:
if (cpu_freq > idle_top_freq) {
hp_state = TEGRA_HP_UP;
queue_delayed_work(
hotplug_wq, &hotplug_work, up_delay);
}
else if (cpu_freq <= idle_bottom_freq) {
hp_state = TEGRA_HP_DOWN;
queue_delayed_work(
hotplug_wq, &hotplug_work, down_delay);
}
break;
case TEGRA_HP_DOWN:
if (cpu_freq > idle_top_freq) {
hp_state = TEGRA_HP_UP;
queue_delayed_work(
hotplug_wq, &hotplug_work, up_delay);
}
else if (cpu_freq > idle_bottom_freq) {
hp_state = TEGRA_HP_IDLE;
}
break;
case TEGRA_HP_UP:
if (cpu_freq <= idle_bottom_freq) {
hp_state = TEGRA_HP_DOWN;
queue_delayed_work(
hotplug_wq, &hotplug_work, down_delay);
}
else if (cpu_freq <= idle_top_freq) {
hp_state = TEGRA_HP_IDLE;
}
break;
default:
pr_err("%s: invalid tegra hotplug state %d\n",
__func__, hp_state);
BUG();
}
mutex_unlock(&tegra_hp_lock);
}
int tegra_auto_hotplug_init(void)
{
/*
* Not bound to the issuer CPU (=> high-priority), has rescue worker
* task, single-threaded, frrezeable.
*/
hotplug_wq = alloc_workqueue(
"cpu-tegra3", WQ_UNBOUND | WQ_RESCUER | WQ_FREEZEABLE, 1);
if (!hotplug_wq)
return -ENOMEM;
INIT_DELAYED_WORK(&hotplug_work, tegra_auto_hotplug_work_func);
lpcpu_max_freq = tegra_get_lpcpu_max_rate() / 1000;
idle_top_freq = lpcpu_max_freq;
idle_bottom_freq = idle_top_freq - IDLE_HYSTERESIS;
up_delay = msecs_to_jiffies(UP_DELAY_MS);
down_delay = msecs_to_jiffies(DOWN_DELAY_MS);
hp_state = INITIAL_STATE;
pr_info("Tegra auto-hotplug initialized: %s\n",
(hp_state == TEGRA_HP_DISABLED) ? "disabled" : "enabled");
return 0;
}
void tegra_auto_hotplug_exit(void)
{
destroy_workqueue(hotplug_wq);
}
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