diff options
| author | Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> | 2012-03-14 00:18:39 +0100 |
|---|---|---|
| committer | Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> | 2012-03-20 20:31:28 +0100 |
| commit | 448c8b1d07d5342922567e138a4b0108a42c24fb (patch) | |
| tree | f995179c7a4afbe3eab6ed30e0d4d33eab5d967d | |
| parent | xen kconfig: relax INPUT_XEN_KBDDEV_FRONTEND deps (diff) | |
| download | linux-448c8b1d07d5342922567e138a4b0108a42c24fb.tar.xz linux-448c8b1d07d5342922567e138a4b0108a42c24fb.zip | |
provide disable_cpufreq() function to disable the API.
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>
| -rw-r--r-- | drivers/cpufreq/cpufreq.c | 24 | ||||
| -rw-r--r-- | include/linux/cpufreq.h | 2 |
2 files changed, 26 insertions, 0 deletions
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 8c2df3499da7..a9a1d81cadc4 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -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)); diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h index 6216115c7789..8ff442753c75 100644 --- a/include/linux/cpufreq.h +++ b/include/linux/cpufreq.h @@ -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 |