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-rw-r--r--arch/arm/kernel/time.c103
1 files changed, 103 insertions, 0 deletions
diff --git a/arch/arm/kernel/time.c b/arch/arm/kernel/time.c
index c232f24f4a60..06054c9ba074 100644
--- a/arch/arm/kernel/time.c
+++ b/arch/arm/kernel/time.c
@@ -381,6 +381,95 @@ static struct sysdev_class timer_sysclass = {
.resume = timer_resume,
};
+#ifdef CONFIG_NO_IDLE_HZ
+static int timer_dyn_tick_enable(void)
+{
+ struct dyn_tick_timer *dyn_tick = system_timer->dyn_tick;
+ unsigned long flags;
+ int ret = -ENODEV;
+
+ if (dyn_tick) {
+ write_seqlock_irqsave(&xtime_lock, flags);
+ ret = 0;
+ if (!(dyn_tick->state & DYN_TICK_ENABLED)) {
+ ret = dyn_tick->enable();
+
+ if (ret == 0)
+ dyn_tick->state |= DYN_TICK_ENABLED;
+ }
+ write_sequnlock_irqrestore(&xtime_lock, flags);
+ }
+
+ return ret;
+}
+
+static int timer_dyn_tick_disable(void)
+{
+ struct dyn_tick_timer *dyn_tick = system_timer->dyn_tick;
+ unsigned long flags;
+ int ret = -ENODEV;
+
+ if (dyn_tick) {
+ write_seqlock_irqsave(&xtime_lock, flags);
+ ret = 0;
+ if (dyn_tick->state & DYN_TICK_ENABLED) {
+ ret = dyn_tick->disable();
+
+ if (ret == 0)
+ dyn_tick->state &= ~DYN_TICK_ENABLED;
+ }
+ write_sequnlock_irqrestore(&xtime_lock, flags);
+ }
+
+ return ret;
+}
+
+void timer_dyn_reprogram(void)
+{
+ struct dyn_tick_timer *dyn_tick = system_timer->dyn_tick;
+ unsigned long flags;
+
+ write_seqlock_irqsave(&xtime_lock, flags);
+ if (dyn_tick->state & DYN_TICK_ENABLED)
+ dyn_tick->reprogram(next_timer_interrupt() - jiffies);
+ write_sequnlock_irqrestore(&xtime_lock, flags);
+}
+
+static ssize_t timer_show_dyn_tick(struct sys_device *dev, char *buf)
+{
+ return sprintf(buf, "%i\n",
+ (system_timer->dyn_tick->state & DYN_TICK_ENABLED) >> 1);
+}
+
+static ssize_t timer_set_dyn_tick(struct sys_device *dev, const char *buf,
+ size_t count)
+{
+ unsigned int enable = simple_strtoul(buf, NULL, 2);
+
+ if (enable)
+ timer_dyn_tick_enable();
+ else
+ timer_dyn_tick_disable();
+
+ return count;
+}
+static SYSDEV_ATTR(dyn_tick, 0644, timer_show_dyn_tick, timer_set_dyn_tick);
+
+/*
+ * dyntick=enable|disable
+ */
+static char dyntick_str[4] __initdata = "";
+
+static int __init dyntick_setup(char *str)
+{
+ if (str)
+ strlcpy(dyntick_str, str, sizeof(dyntick_str));
+ return 1;
+}
+
+__setup("dyntick=", dyntick_setup);
+#endif
+
static int __init timer_init_sysfs(void)
{
int ret = sysdev_class_register(&timer_sysclass);
@@ -388,6 +477,20 @@ static int __init timer_init_sysfs(void)
system_timer->dev.cls = &timer_sysclass;
ret = sysdev_register(&system_timer->dev);
}
+
+#ifdef CONFIG_NO_IDLE_HZ
+ if (ret == 0 && system_timer->dyn_tick) {
+ ret = sysdev_create_file(&system_timer->dev, &attr_dyn_tick);
+
+ /*
+ * Turn on dynamic tick after calibrate delay
+ * for correct bogomips
+ */
+ if (ret == 0 && dyntick_str[0] == 'e')
+ ret = timer_dyn_tick_enable();
+ }
+#endif
+
return ret;
}