linux/drivers/cpufreq/exynos-cpufreq.c
Viresh Kumar c3aca6b1ce cpufreq: exynos: call CPUFREQ_POSTCHANGE notfier in error cases
PRECHANGE and POSTCHANGE notifiers must be called in groups, i.e either both
should be called or both shouldn't be.

In case we have started PRECHANGE notifier and found an error, we must call
POSTCHANGE notifier with freqs.new = freqs.old to guarantee that sequence of
calling notifiers is complete.

This patch fixes it.

Cc: Kukjin Kim <kgene.kim@samsung.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
2013-06-24 18:18:59 +05:30

339 lines
8.1 KiB
C

/*
* Copyright (c) 2010-2011 Samsung Electronics Co., Ltd.
* http://www.samsung.com
*
* EXYNOS - CPU frequency scaling support for EXYNOS series
*
* 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/kernel.h>
#include <linux/err.h>
#include <linux/clk.h>
#include <linux/io.h>
#include <linux/slab.h>
#include <linux/regulator/consumer.h>
#include <linux/cpufreq.h>
#include <linux/suspend.h>
#include <plat/cpu.h>
#include "exynos-cpufreq.h"
static struct exynos_dvfs_info *exynos_info;
static struct regulator *arm_regulator;
static struct cpufreq_freqs freqs;
static unsigned int locking_frequency;
static bool frequency_locked;
static DEFINE_MUTEX(cpufreq_lock);
static int exynos_verify_speed(struct cpufreq_policy *policy)
{
return cpufreq_frequency_table_verify(policy,
exynos_info->freq_table);
}
static unsigned int exynos_getspeed(unsigned int cpu)
{
return clk_get_rate(exynos_info->cpu_clk) / 1000;
}
static int exynos_cpufreq_get_index(unsigned int freq)
{
struct cpufreq_frequency_table *freq_table = exynos_info->freq_table;
int index;
for (index = 0;
freq_table[index].frequency != CPUFREQ_TABLE_END; index++)
if (freq_table[index].frequency == freq)
break;
if (freq_table[index].frequency == CPUFREQ_TABLE_END)
return -EINVAL;
return index;
}
static int exynos_cpufreq_scale(unsigned int target_freq)
{
struct cpufreq_frequency_table *freq_table = exynos_info->freq_table;
unsigned int *volt_table = exynos_info->volt_table;
struct cpufreq_policy *policy = cpufreq_cpu_get(0);
unsigned int arm_volt, safe_arm_volt = 0;
unsigned int mpll_freq_khz = exynos_info->mpll_freq_khz;
int index, old_index;
int ret = 0;
freqs.old = policy->cur;
freqs.new = target_freq;
if (freqs.new == freqs.old)
goto out;
/*
* The policy max have been changed so that we cannot get proper
* old_index with cpufreq_frequency_table_target(). Thus, ignore
* policy and get the index from the raw freqeuncy table.
*/
old_index = exynos_cpufreq_get_index(freqs.old);
if (old_index < 0) {
ret = old_index;
goto out;
}
index = exynos_cpufreq_get_index(target_freq);
if (index < 0) {
ret = index;
goto out;
}
/*
* ARM clock source will be changed APLL to MPLL temporary
* To support this level, need to control regulator for
* required voltage level
*/
if (exynos_info->need_apll_change != NULL) {
if (exynos_info->need_apll_change(old_index, index) &&
(freq_table[index].frequency < mpll_freq_khz) &&
(freq_table[old_index].frequency < mpll_freq_khz))
safe_arm_volt = volt_table[exynos_info->pll_safe_idx];
}
arm_volt = volt_table[index];
cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE);
/* When the new frequency is higher than current frequency */
if ((freqs.new > freqs.old) && !safe_arm_volt) {
/* Firstly, voltage up to increase frequency */
ret = regulator_set_voltage(arm_regulator, arm_volt, arm_volt);
if (ret) {
pr_err("%s: failed to set cpu voltage to %d\n",
__func__, arm_volt);
freqs.new = freqs.old;
goto post_notify;
}
}
if (safe_arm_volt) {
ret = regulator_set_voltage(arm_regulator, safe_arm_volt,
safe_arm_volt);
if (ret) {
pr_err("%s: failed to set cpu voltage to %d\n",
__func__, safe_arm_volt);
freqs.new = freqs.old;
goto post_notify;
}
}
exynos_info->set_freq(old_index, index);
post_notify:
cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);
if (ret)
goto out;
/* When the new frequency is lower than current frequency */
if ((freqs.new < freqs.old) ||
((freqs.new > freqs.old) && safe_arm_volt)) {
/* down the voltage after frequency change */
regulator_set_voltage(arm_regulator, arm_volt,
arm_volt);
if (ret) {
pr_err("%s: failed to set cpu voltage to %d\n",
__func__, arm_volt);
goto out;
}
}
out:
cpufreq_cpu_put(policy);
return ret;
}
static int exynos_target(struct cpufreq_policy *policy,
unsigned int target_freq,
unsigned int relation)
{
struct cpufreq_frequency_table *freq_table = exynos_info->freq_table;
unsigned int index;
unsigned int new_freq;
int ret = 0;
mutex_lock(&cpufreq_lock);
if (frequency_locked)
goto out;
if (cpufreq_frequency_table_target(policy, freq_table,
target_freq, relation, &index)) {
ret = -EINVAL;
goto out;
}
new_freq = freq_table[index].frequency;
ret = exynos_cpufreq_scale(new_freq);
out:
mutex_unlock(&cpufreq_lock);
return ret;
}
#ifdef CONFIG_PM
static int exynos_cpufreq_suspend(struct cpufreq_policy *policy)
{
return 0;
}
static int exynos_cpufreq_resume(struct cpufreq_policy *policy)
{
return 0;
}
#endif
/**
* exynos_cpufreq_pm_notifier - block CPUFREQ's activities in suspend-resume
* context
* @notifier
* @pm_event
* @v
*
* While frequency_locked == true, target() ignores every frequency but
* locking_frequency. The locking_frequency value is the initial frequency,
* which is set by the bootloader. In order to eliminate possible
* inconsistency in clock values, we save and restore frequencies during
* suspend and resume and block CPUFREQ activities. Note that the standard
* suspend/resume cannot be used as they are too deep (syscore_ops) for
* regulator actions.
*/
static int exynos_cpufreq_pm_notifier(struct notifier_block *notifier,
unsigned long pm_event, void *v)
{
int ret;
switch (pm_event) {
case PM_SUSPEND_PREPARE:
mutex_lock(&cpufreq_lock);
frequency_locked = true;
mutex_unlock(&cpufreq_lock);
ret = exynos_cpufreq_scale(locking_frequency);
if (ret < 0)
return NOTIFY_BAD;
break;
case PM_POST_SUSPEND:
mutex_lock(&cpufreq_lock);
frequency_locked = false;
mutex_unlock(&cpufreq_lock);
break;
}
return NOTIFY_OK;
}
static struct notifier_block exynos_cpufreq_nb = {
.notifier_call = exynos_cpufreq_pm_notifier,
};
static int exynos_cpufreq_cpu_init(struct cpufreq_policy *policy)
{
policy->cur = policy->min = policy->max = exynos_getspeed(policy->cpu);
cpufreq_frequency_table_get_attr(exynos_info->freq_table, policy->cpu);
/* set the transition latency value */
policy->cpuinfo.transition_latency = 100000;
cpumask_setall(policy->cpus);
return cpufreq_frequency_table_cpuinfo(policy, exynos_info->freq_table);
}
static int exynos_cpufreq_cpu_exit(struct cpufreq_policy *policy)
{
cpufreq_frequency_table_put_attr(policy->cpu);
return 0;
}
static struct freq_attr *exynos_cpufreq_attr[] = {
&cpufreq_freq_attr_scaling_available_freqs,
NULL,
};
static struct cpufreq_driver exynos_driver = {
.flags = CPUFREQ_STICKY,
.verify = exynos_verify_speed,
.target = exynos_target,
.get = exynos_getspeed,
.init = exynos_cpufreq_cpu_init,
.exit = exynos_cpufreq_cpu_exit,
.name = "exynos_cpufreq",
.attr = exynos_cpufreq_attr,
#ifdef CONFIG_PM
.suspend = exynos_cpufreq_suspend,
.resume = exynos_cpufreq_resume,
#endif
};
static int __init exynos_cpufreq_init(void)
{
int ret = -EINVAL;
exynos_info = kzalloc(sizeof(struct exynos_dvfs_info), GFP_KERNEL);
if (!exynos_info)
return -ENOMEM;
if (soc_is_exynos4210())
ret = exynos4210_cpufreq_init(exynos_info);
else if (soc_is_exynos4212() || soc_is_exynos4412())
ret = exynos4x12_cpufreq_init(exynos_info);
else if (soc_is_exynos5250())
ret = exynos5250_cpufreq_init(exynos_info);
else
return 0;
if (ret)
goto err_vdd_arm;
if (exynos_info->set_freq == NULL) {
pr_err("%s: No set_freq function (ERR)\n", __func__);
goto err_vdd_arm;
}
arm_regulator = regulator_get(NULL, "vdd_arm");
if (IS_ERR(arm_regulator)) {
pr_err("%s: failed to get resource vdd_arm\n", __func__);
goto err_vdd_arm;
}
locking_frequency = exynos_getspeed(0);
register_pm_notifier(&exynos_cpufreq_nb);
if (cpufreq_register_driver(&exynos_driver)) {
pr_err("%s: failed to register cpufreq driver\n", __func__);
goto err_cpufreq;
}
return 0;
err_cpufreq:
unregister_pm_notifier(&exynos_cpufreq_nb);
regulator_put(arm_regulator);
err_vdd_arm:
kfree(exynos_info);
pr_debug("%s: failed initialization\n", __func__);
return -EINVAL;
}
late_initcall(exynos_cpufreq_init);