[PATCH] ARM: Generic Dynamic Tick Timer support for ARM, take 4
[linux-2.6.git] / arch / arm / kernel / time.c
index c232f24..06054c9 100644 (file)
@@ -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;
 }