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path: root/drivers/cpufreq/powernv-cpufreq.c
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Diffstat (limited to 'drivers/cpufreq/powernv-cpufreq.c')
-rw-r--r--drivers/cpufreq/powernv-cpufreq.c44
1 files changed, 44 insertions, 0 deletions
diff --git a/drivers/cpufreq/powernv-cpufreq.c b/drivers/cpufreq/powernv-cpufreq.c
index 379c0837f5a9..2dfd4fdb5a52 100644
--- a/drivers/cpufreq/powernv-cpufreq.c
+++ b/drivers/cpufreq/powernv-cpufreq.c
@@ -26,6 +26,7 @@
#include <linux/cpufreq.h>
#include <linux/smp.h>
#include <linux/of.h>
+#include <linux/reboot.h>
#include <asm/cputhreads.h>
#include <asm/firmware.h>
@@ -35,6 +36,7 @@
#define POWERNV_MAX_PSTATES 256
static struct cpufreq_frequency_table powernv_freqs[POWERNV_MAX_PSTATES+1];
+static bool rebooting;
/*
* Note: The set of pstates consists of contiguous integers, the
@@ -284,6 +286,15 @@ static void set_pstate(void *freq_data)
}
/*
+ * get_nominal_index: Returns the index corresponding to the nominal
+ * pstate in the cpufreq table
+ */
+static inline unsigned int get_nominal_index(void)
+{
+ return powernv_pstate_info.max - powernv_pstate_info.nominal;
+}
+
+/*
* powernv_cpufreq_target_index: Sets the frequency corresponding to
* the cpufreq table entry indexed by new_index on the cpus in the
* mask policy->cpus
@@ -293,6 +304,9 @@ static int powernv_cpufreq_target_index(struct cpufreq_policy *policy,
{
struct powernv_smp_call_data freq_data;
+ if (unlikely(rebooting) && new_index != get_nominal_index())
+ return 0;
+
freq_data.pstate_id = powernv_freqs[new_index].driver_data;
/*
@@ -317,6 +331,33 @@ static int powernv_cpufreq_cpu_init(struct cpufreq_policy *policy)
return cpufreq_table_validate_and_show(policy, powernv_freqs);
}
+static int powernv_cpufreq_reboot_notifier(struct notifier_block *nb,
+ unsigned long action, void *unused)
+{
+ int cpu;
+ struct cpufreq_policy cpu_policy;
+
+ rebooting = true;
+ for_each_online_cpu(cpu) {
+ cpufreq_get_policy(&cpu_policy, cpu);
+ powernv_cpufreq_target_index(&cpu_policy, get_nominal_index());
+ }
+
+ return NOTIFY_DONE;
+}
+
+static struct notifier_block powernv_cpufreq_reboot_nb = {
+ .notifier_call = powernv_cpufreq_reboot_notifier,
+};
+
+static void powernv_cpufreq_stop_cpu(struct cpufreq_policy *policy)
+{
+ struct powernv_smp_call_data freq_data;
+
+ freq_data.pstate_id = powernv_pstate_info.min;
+ smp_call_function_single(policy->cpu, set_pstate, &freq_data, 1);
+}
+
static struct cpufreq_driver powernv_cpufreq_driver = {
.name = "powernv-cpufreq",
.flags = CPUFREQ_CONST_LOOPS,
@@ -324,6 +365,7 @@ static struct cpufreq_driver powernv_cpufreq_driver = {
.verify = cpufreq_generic_frequency_table_verify,
.target_index = powernv_cpufreq_target_index,
.get = powernv_cpufreq_get,
+ .stop_cpu = powernv_cpufreq_stop_cpu,
.attr = powernv_cpu_freq_attr,
};
@@ -342,12 +384,14 @@ static int __init powernv_cpufreq_init(void)
return rc;
}
+ register_reboot_notifier(&powernv_cpufreq_reboot_nb);
return cpufreq_register_driver(&powernv_cpufreq_driver);
}
module_init(powernv_cpufreq_init);
static void __exit powernv_cpufreq_exit(void)
{
+ unregister_reboot_notifier(&powernv_cpufreq_reboot_nb);
cpufreq_unregister_driver(&powernv_cpufreq_driver);
}
module_exit(powernv_cpufreq_exit);