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provide disable_cpufreq() function to disable the API.

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useful for disabling cpufreq altogether. The cpu frequency
scaling drivers and cpu frequency governors will fail to register.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Dave Jones <davej@redhat.com>
This commit is contained in:
Konrad Rzeszutek Wilk 2012-03-13 19:18:39 -04:00
parent 4bc25af79e
commit 448c8b1d07
2 changed files with 26 additions and 0 deletions
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24
drivers/cpufreq/cpufreq.c
View File

@ -126,6 +126,15 @@ static int __init init_cpufreq_transition_notifier_list(void)
}
pure_initcall(init_cpufreq_transition_notifier_list);
static int off __read_mostly;
int cpufreq_disabled(void)
{
return off;
}
void disable_cpufreq(void)
{
off = 1;
}
static LIST_HEAD(cpufreq_governor_list);
static DEFINE_MUTEX(cpufreq_governor_mutex);
@ -1442,6 +1451,9 @@ int __cpufreq_driver_target(struct cpufreq_policy *policy,
{
int retval = -EINVAL;
if (cpufreq_disabled())
return -ENODEV;
pr_debug("target for CPU %u: %u kHz, relation %u\n", policy->cpu,
target_freq, relation);
if (cpu_online(policy->cpu) && cpufreq_driver->target)
@ -1550,6 +1562,9 @@ int cpufreq_register_governor(struct cpufreq_governor *governor)
if (!governor)
return -EINVAL;
if (cpufreq_disabled())
return -ENODEV;
mutex_lock(&cpufreq_governor_mutex);
err = -EBUSY;
@ -1573,6 +1588,9 @@ void cpufreq_unregister_governor(struct cpufreq_governor *governor)
if (!governor)
return;
if (cpufreq_disabled())
return;
#ifdef CONFIG_HOTPLUG_CPU
for_each_present_cpu(cpu) {
if (cpu_online(cpu))
@ -1815,6 +1833,9 @@ int cpufreq_register_driver(struct cpufreq_driver *driver_data)
unsigned long flags;
int ret;
if (cpufreq_disabled())
return -ENODEV;
if (!driver_data || !driver_data->verify || !driver_data->init ||
((!driver_data->setpolicy) && (!driver_data->target)))
return -EINVAL;
@ -1902,6 +1923,9 @@ static int __init cpufreq_core_init(void)
{
int cpu;
if (cpufreq_disabled())
return -ENODEV;
for_each_possible_cpu(cpu) {
per_cpu(cpufreq_policy_cpu, cpu) = -1;
init_rwsem(&per_cpu(cpu_policy_rwsem, cpu));

2
include/linux/cpufreq.h
View File

@ -35,6 +35,7 @@
#ifdef CONFIG_CPU_FREQ
int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list);
int cpufreq_unregister_notifier(struct notifier_block *nb, unsigned int list);
extern void disable_cpufreq(void);
#else /* CONFIG_CPU_FREQ */
static inline int cpufreq_register_notifier(struct notifier_block *nb,
unsigned int list)
@ -46,6 +47,7 @@ static inline int cpufreq_unregister_notifier(struct notifier_block *nb,
{
return 0;
}
static inline void disable_cpufreq(void) { }
#endif /* CONFIG_CPU_FREQ */
/* if (cpufreq_driver->target) exists, the ->governor decides what frequency