Add the rt linux 4.1.3-rt3 as base

[kvmfornfv.git] / kernel / kernel / time / tick-oneshot.c

diff --git a/kernel/kernel/time/tick-oneshot.c b/kernel/kernel/time/tick-oneshot.c
new file mode 100644 (file)
index 0000000..67a64b1
--- /dev/null
+++ b/kernel/kernel/time/tick-oneshot.c
@@ -0,0 +1,116 @@
+/*
+ * linux/kernel/time/tick-oneshot.c
+ *
+ * This file contains functions which manage high resolution tick
+ * related events.
+ *
+ * Copyright(C) 2005-2006, Thomas Gleixner <tglx@linutronix.de>
+ * Copyright(C) 2005-2007, Red Hat, Inc., Ingo Molnar
+ * Copyright(C) 2006-2007, Timesys Corp., Thomas Gleixner
+ *
+ * This code is licenced under the GPL version 2. For details see
+ * kernel-base/COPYING.
+ */
+#include <linux/cpu.h>
+#include <linux/err.h>
+#include <linux/hrtimer.h>
+#include <linux/interrupt.h>
+#include <linux/percpu.h>
+#include <linux/profile.h>
+#include <linux/sched.h>
+
+#include "tick-internal.h"
+
+/**
+ * tick_program_event
+ */
+int tick_program_event(ktime_t expires, int force)
+{
+       struct clock_event_device *dev = __this_cpu_read(tick_cpu_device.evtdev);
+
+       return clockevents_program_event(dev, expires, force);
+}
+
+/**
+ * tick_resume_onshot - resume oneshot mode
+ */
+void tick_resume_oneshot(void)
+{
+       struct clock_event_device *dev = __this_cpu_read(tick_cpu_device.evtdev);
+
+       clockevents_set_state(dev, CLOCK_EVT_STATE_ONESHOT);
+       clockevents_program_event(dev, ktime_get(), true);
+}
+
+/**
+ * tick_setup_oneshot - setup the event device for oneshot mode (hres or nohz)
+ */
+void tick_setup_oneshot(struct clock_event_device *newdev,
+                       void (*handler)(struct clock_event_device *),
+                       ktime_t next_event)
+{
+       newdev->event_handler = handler;
+       clockevents_set_state(newdev, CLOCK_EVT_STATE_ONESHOT);
+       clockevents_program_event(newdev, next_event, true);
+}
+
+/**
+ * tick_switch_to_oneshot - switch to oneshot mode
+ */
+int tick_switch_to_oneshot(void (*handler)(struct clock_event_device *))
+{
+       struct tick_device *td = this_cpu_ptr(&tick_cpu_device);
+       struct clock_event_device *dev = td->evtdev;
+
+       if (!dev || !(dev->features & CLOCK_EVT_FEAT_ONESHOT) ||
+                   !tick_device_is_functional(dev)) {
+
+               printk(KERN_INFO "Clockevents: "
+                      "could not switch to one-shot mode:");
+               if (!dev) {
+                       printk(" no tick device\n");
+               } else {
+                       if (!tick_device_is_functional(dev))
+                               printk(" %s is not functional.\n", dev->name);
+                       else
+                               printk(" %s does not support one-shot mode.\n",
+                                      dev->name);
+               }
+               return -EINVAL;
+       }
+
+       td->mode = TICKDEV_MODE_ONESHOT;
+       dev->event_handler = handler;
+       clockevents_set_state(dev, CLOCK_EVT_STATE_ONESHOT);
+       tick_broadcast_switch_to_oneshot();
+       return 0;
+}
+
+/**
+ * tick_check_oneshot_mode - check whether the system is in oneshot mode
+ *
+ * returns 1 when either nohz or highres are enabled. otherwise 0.
+ */
+int tick_oneshot_mode_active(void)
+{
+       unsigned long flags;
+       int ret;
+
+       local_irq_save(flags);
+       ret = __this_cpu_read(tick_cpu_device.mode) == TICKDEV_MODE_ONESHOT;
+       local_irq_restore(flags);
+
+       return ret;
+}
+
+#ifdef CONFIG_HIGH_RES_TIMERS
+/**
+ * tick_init_highres - switch to high resolution mode
+ *
+ * Called with interrupts disabled.
+ */
+int tick_init_highres(void)
+{
+       return tick_switch_to_oneshot(hrtimer_interrupt);
+}
+#endif