2 files changed, 347 insertions, 0 deletions
diff --git a/kernel/time/Makefile b/kernel/time/Makefile
index 61a3907d16f..2bf1805914d 100644
--- a/kernel/time/Makefile
+++ b/kernel/time/Makefile
@@ -1 +1,3 @@
 obj-y += ntp.o clocksource.o jiffies.o
+
+obj-$(CONFIG_GENERIC_CLOCKEVENTS) += clockevents.o
diff --git a/kernel/time/clockevents.c b/kernel/time/clockevents.c
new file mode 100644
index 00000000000..67932ea78c1
--- /dev/null
+++ b/kernel/time/clockevents.c
@@ -0,0 +1,345 @@
+/*
+ * linux/kernel/time/clockevents.c
+ *
+ * This file contains functions which manage clock event devices.
+ *
+ * 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/clockchips.h>
+#include <linux/hrtimer.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/notifier.h>
+#include <linux/smp.h>
+#include <linux/sysdev.h>
+
+/* The registered clock event devices */
+static LIST_HEAD(clockevent_devices);
+static LIST_HEAD(clockevents_released);
+
+/* Notification for clock events */
+static RAW_NOTIFIER_HEAD(clockevents_chain);
+
+/* Protection for the above */
+static DEFINE_SPINLOCK(clockevents_lock);
+
+/**
+ * clockevents_delta2ns - Convert a latch value (device ticks) to nanoseconds
+ * @latch:	value to convert
+ * @evt:	pointer to clock event device descriptor
+ *
+ * Math helper, returns latch value converted to nanoseconds (bound checked)
+ */
+unsigned long clockevent_delta2ns(unsigned long latch,
+				  struct clock_event_device *evt)
+{
+	u64 clc = ((u64) latch << evt->shift);
+
+	do_div(clc, evt->mult);
+	if (clc < 1000)
+		clc = 1000;
+	if (clc > LONG_MAX)
+		clc = LONG_MAX;
+
+	return (unsigned long) clc;
+}
+
+/**
+ * clockevents_set_mode - set the operating mode of a clock event device
+ * @dev:	device to modify
+ * @mode:	new mode
+ *
+ * Must be called with interrupts disabled !
+ */
+void clockevents_set_mode(struct clock_event_device *dev,
+				 enum clock_event_mode mode)
+{
+	if (dev->mode != mode) {
+		dev->set_mode(mode, dev);
+		dev->mode = mode;
+	}
+}
+
+/**
+ * clockevents_program_event - Reprogram the clock event device.
+ * @expires:	absolute expiry time (monotonic clock)
+ *
+ * Returns 0 on success, -ETIME when the event is in the past.
+ */
+int clockevents_program_event(struct clock_event_device *dev, ktime_t expires,
+			      ktime_t now)
+{
+	unsigned long long clc;
+	int64_t delta;
+
+	delta = ktime_to_ns(ktime_sub(expires, now));
+
+	if (delta <= 0)
+		return -ETIME;
+
+	dev->next_event = expires;
+
+	if (dev->mode == CLOCK_EVT_MODE_SHUTDOWN)
+		return 0;
+
+	if (delta > dev->max_delta_ns)
+		delta = dev->max_delta_ns;
+	if (delta < dev->min_delta_ns)
+		delta = dev->min_delta_ns;
+
+	clc = delta * dev->mult;
+	clc >>= dev->shift;
+
+	return dev->set_next_event((unsigned long) clc, dev);
+}
+
+/**
+ * clockevents_register_notifier - register a clock events change listener
+ */
+int clockevents_register_notifier(struct notifier_block *nb)
+{
+	int ret;
+
+	spin_lock(&clockevents_lock);
+	ret = raw_notifier_chain_register(&clockevents_chain, nb);
+	spin_unlock(&clockevents_lock);
+
+	return ret;
+}
+
+/**
+ * clockevents_unregister_notifier - unregister a clock events change listener
+ */
+void clockevents_unregister_notifier(struct notifier_block *nb)
+{
+	spin_lock(&clockevents_lock);
+	raw_notifier_chain_unregister(&clockevents_chain, nb);
+	spin_unlock(&clockevents_lock);
+}
+
+/*
+ * Notify about a clock event change. Called with clockevents_lock
+ * held.
+ */
+static void clockevents_do_notify(unsigned long reason, void *dev)
+{
+	raw_notifier_call_chain(&clockevents_chain, reason, dev);
+}
+
+/*
+ * Called after a notify add to make devices availble which were
+ * released from the notifier call.
+ */
+static void clockevents_notify_released(void)
+{
+	struct clock_event_device *dev;
+
+	while (!list_empty(&clockevents_released)) {
+		dev = list_entry(clockevents_released.next,
+				 struct clock_event_device, list);
+		list_del(&dev->list);
+		list_add(&dev->list, &clockevent_devices);
+		clockevents_do_notify(CLOCK_EVT_NOTIFY_ADD, dev);
+	}
+}
+
+/**
+ * clockevents_register_device - register a clock event device
+ * @dev:	device to register
+ */
+void clockevents_register_device(struct clock_event_device *dev)
+{
+	BUG_ON(dev->mode != CLOCK_EVT_MODE_UNUSED);
+
+	spin_lock(&clockevents_lock);
+
+	list_add(&dev->list, &clockevent_devices);
+	clockevents_do_notify(CLOCK_EVT_NOTIFY_ADD, dev);
+	clockevents_notify_released();
+
+	spin_unlock(&clockevents_lock);
+}
+
+/*
+ * Noop handler when we shut down an event device
+ */
+static void clockevents_handle_noop(struct clock_event_device *dev)
+{
+}
+
+/**
+ * clockevents_exchange_device - release and request clock devices
+ * @old:	device to release (can be NULL)
+ * @new:	device to request (can be NULL)
+ *
+ * Called from the notifier chain. clockevents_lock is held already
+ */
+void clockevents_exchange_device(struct clock_event_device *old,
+				 struct clock_event_device *new)
+{
+	unsigned long flags;
+
+	local_irq_save(flags);
+	/*
+	 * Caller releases a clock event device. We queue it into the
+	 * released list and do a notify add later.
+	 */
+	if (old) {
+		old->event_handler = clockevents_handle_noop;
+		clockevents_set_mode(old, CLOCK_EVT_MODE_UNUSED);
+		list_del(&old->list);
+		list_add(&old->list, &clockevents_released);
+	}
+
+	if (new) {
+		BUG_ON(new->mode != CLOCK_EVT_MODE_UNUSED);
+		clockevents_set_mode(new, CLOCK_EVT_MODE_SHUTDOWN);
+	}
+	local_irq_restore(flags);
+}
+
+/**
+ * clockevents_request_device
+ */
+struct clock_event_device *clockevents_request_device(unsigned int features,
+						      cpumask_t cpumask)
+{
+	struct clock_event_device *cur, *dev = NULL;
+	struct list_head *tmp;
+
+	spin_lock(&clockevents_lock);
+
+	list_for_each(tmp, &clockevent_devices) {
+		cur = list_entry(tmp, struct clock_event_device, list);
+
+		if ((cur->features & features) == features &&
+		    cpus_equal(cpumask, cur->cpumask)) {
+			if (!dev || dev->rating < cur->rating)
+				dev = cur;
+		}
+	}
+
+	clockevents_exchange_device(NULL, dev);
+
+	spin_unlock(&clockevents_lock);
+
+	return dev;
+}
+
+/**
+ * clockevents_release_device
+ */
+void clockevents_release_device(struct clock_event_device *dev)
+{
+	spin_lock(&clockevents_lock);
+
+	clockevents_exchange_device(dev, NULL);
+	clockevents_notify_released();
+
+	spin_unlock(&clockevents_lock);
+}
+
+/**
+ * clockevents_notify - notification about relevant events
+ */
+void clockevents_notify(unsigned long reason, void *arg)
+{
+	spin_lock(&clockevents_lock);
+	clockevents_do_notify(reason, arg);
+
+	switch (reason) {
+	case CLOCK_EVT_NOTIFY_CPU_DEAD:
+		/*
+		 * Unregister the clock event devices which were
+		 * released from the users in the notify chain.
+		 */
+		while (!list_empty(&clockevents_released)) {
+			struct clock_event_device *dev;
+
+			dev = list_entry(clockevents_released.next,
+					 struct clock_event_device, list);
+			list_del(&dev->list);
+		}
+		break;
+	default:
+		break;
+	}
+	spin_unlock(&clockevents_lock);
+}
+EXPORT_SYMBOL_GPL(clockevents_notify);
+
+#ifdef CONFIG_SYSFS
+
+/**
+ * clockevents_show_registered - sysfs interface for listing clockevents
+ * @dev:	unused
+ * @buf:	char buffer to be filled with clock events list
+ *
+ * Provides sysfs interface for listing registered clock event devices
+ */
+static ssize_t clockevents_show_registered(struct sys_device *dev, char *buf)
+{
+	struct list_head *tmp;
+	char *p = buf;
+	int cpu;
+
+	spin_lock(&clockevents_lock);
+
+	list_for_each(tmp, &clockevent_devices) {
+		struct clock_event_device *ce;
+
+		ce = list_entry(tmp, struct clock_event_device, list);
+		p += sprintf(p, "%-20s F:%04x M:%d", ce->name,
+			     ce->features, ce->mode);
+		p += sprintf(p, " C:");
+		if (!cpus_equal(ce->cpumask, cpu_possible_map)) {
+			for_each_cpu_mask(cpu, ce->cpumask)
+				p += sprintf(p, " %d", cpu);
+		} else {
+			/*
+			 * FIXME: Add the cpu which is handling this sucker
+			 */
+		}
+		p += sprintf(p, "\n");
+	}
+
+	spin_unlock(&clockevents_lock);
+
+	return p - buf;
+}
+
+/*
+ * Sysfs setup bits:
+ */
+static SYSDEV_ATTR(registered, 0600,
+		   clockevents_show_registered, NULL);
+
+static struct sysdev_class clockevents_sysclass = {
+	set_kset_name("clockevents"),
+};
+
+static struct sys_device clockevents_sys_device = {
+	.id	= 0,
+	.cls	= &clockevents_sysclass,
+};
+
+static int __init clockevents_sysfs_init(void)
+{
+	int error = sysdev_class_register(&clockevents_sysclass);
+
+	if (!error)
+		error = sysdev_register(&clockevents_sys_device);
+	if (!error)
+		error = sysdev_create_file(
+				&clockevents_sys_device,
+				&attr_registered);
+	return error;
+}
+device_initcall(clockevents_sysfs_init);
+#endif