From a7b422cda5084db7265c3b23310a959b43b47529 Mon Sep 17 00:00:00 2001
From: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Date: Tue, 13 Mar 2012 19:18:39 -0400
Subject: 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>
---
drivers/cpufreq/cpufreq.c | 24 ++++++++++++++++++++++++
1 file changed, 24 insertions(+)
(limited to 'drivers/cpufreq/cpufreq.c')
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 622013fb7890..7f2f149ae40f 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);
@@ -1441,6 +1450,9 @@ 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)
@@ -1549,6 +1561,9 @@ int cpufreq_register_governor(struct cpufreq_governor *governor)
if (!governor)
return -EINVAL;
+ if (cpufreq_disabled())
+ return -ENODEV;
+
mutex_lock(&cpufreq_governor_mutex);
err = -EBUSY;
@@ -1572,6 +1587,9 @@ 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))
@@ -1814,6 +1832,9 @@ 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;
@@ -1901,6 +1922,9 @@ 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));
--
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