[PATCH] hrtimer: hrtimer core code

hrtimer subsystem core.  It is initialized at bootup and expired by the timer
interrupt, but is otherwise not utilized by any other subsystem yet.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

2 files changed, 145 insertions, 0 deletions

diff --git a/include/linux/hrtimer.h b/include/linux/hrtimer.h
new file mode 100644
index 000000000000..64f8d554fbb8
--- /dev/null
+++ b/include/linux/hrtimer.h
@@ -0,0 +1,130 @@
+/*
+ *  include/linux/hrtimer.h
+ *
+ *  hrtimers - High-resolution kernel timers
+ *
+ *   Copyright(C) 2005, Thomas Gleixner <tglx@linutronix.de>
+ *   Copyright(C) 2005, Red Hat, Inc., Ingo Molnar
+ *
+ *  data type definitions, declarations, prototypes
+ *
+ *  Started by: Thomas Gleixner and Ingo Molnar
+ *
+ *  For licencing details see kernel-base/COPYING
+ */
+#ifndef _LINUX_HRTIMER_H
+#define _LINUX_HRTIMER_H
+
+#include <linux/rbtree.h>
+#include <linux/ktime.h>
+#include <linux/init.h>
+#include <linux/list.h>
+#include <linux/wait.h>
+
+/*
+ * Mode arguments of xxx_hrtimer functions:
+ */
+enum hrtimer_mode {
+        HRTIMER_ABS,    /* Time value is absolute */
+        HRTIMER_REL,    /* Time value is relative to now */
+};
+
+enum hrtimer_restart {
+        HRTIMER_NORESTART,
+        HRTIMER_RESTART,
+};
+
+/*
+ * Timer states:
+ */
+enum hrtimer_state {
+        HRTIMER_INACTIVE,       /* Timer is inactive */
+        HRTIMER_EXPIRED,                /* Timer is expired */
+        HRTIMER_PENDING,                /* Timer is pending */
+};
+
+struct hrtimer_base;
+
+/**
+ * struct hrtimer - the basic hrtimer structure
+ *
+ * @node:       red black tree node for time ordered insertion
+ * @list:       list head for easier access to the time ordered list,
+ *              without walking the red black tree.
+ * @expires:    the absolute expiry time in the hrtimers internal
+ *              representation. The time is related to the clock on
+ *              which the timer is based.
+ * @state:      state of the timer
+ * @function:   timer expiry callback function
+ * @data:       argument for the callback function
+ * @base:       pointer to the timer base (per cpu and per clock)
+ *
+ * The hrtimer structure must be initialized by init_hrtimer_#CLOCKTYPE()
+ */
+struct hrtimer {
+        struct rb_node          node;
+        struct list_head        list;
+        ktime_t                 expires;
+        enum hrtimer_state      state;
+        int                     (*function)(void *);
+        void                    *data;
+        struct hrtimer_base     *base;
+};
+
+/**
+ * struct hrtimer_base - the timer base for a specific clock
+ *
+ * @index:      clock type index for per_cpu support when moving a timer
+ *              to a base on another cpu.
+ * @lock:       lock protecting the base and associated timers
+ * @active:     red black tree root node for the active timers
+ * @pending:    list of pending timers for simple time ordered access
+ * @resolution: the resolution of the clock, in nanoseconds
+ * @get_time:   function to retrieve the current time of the clock
+ * @curr_timer: the timer which is executing a callback right now
+ */
+struct hrtimer_base {
+        clockid_t               index;
+        spinlock_t              lock;
+        struct rb_root          active;
+        struct list_head        pending;
+        unsigned long           resolution;
+        ktime_t                 (*get_time)(void);
+        struct hrtimer          *curr_timer;
+};
+
+/* Exported timer functions: */
+
+/* Initialize timers: */
+extern void hrtimer_init(struct hrtimer *timer, const clockid_t which_clock);
+extern void hrtimer_rebase(struct hrtimer *timer, const clockid_t which_clock);
+
+
+/* Basic timer operations: */
+extern int hrtimer_start(struct hrtimer *timer, ktime_t tim,
+                         const enum hrtimer_mode mode);
+extern int hrtimer_cancel(struct hrtimer *timer);
+extern int hrtimer_try_to_cancel(struct hrtimer *timer);
+
+#define hrtimer_restart(timer) hrtimer_start((timer), (timer)->expires, HRTIMER_ABS)
+
+/* Query timers: */
+extern ktime_t hrtimer_get_remaining(const struct hrtimer *timer);
+extern int hrtimer_get_res(const clockid_t which_clock, struct timespec *tp);
+
+static inline int hrtimer_active(const struct hrtimer *timer)
+{
+        return timer->state == HRTIMER_PENDING;
+}
+
+/* Forward a hrtimer so it expires after now: */
+extern unsigned long hrtimer_forward(struct hrtimer *timer,
+                                     const ktime_t interval);
+
+/* Soft interrupt function to run the hrtimer queues: */
+extern void hrtimer_run_queues(void);
+
+/* Bootup initialization: */
+extern void __init hrtimers_init(void);
+
+#endif
diff --git a/include/linux/ktime.h b/include/linux/ktime.h
index 5b9a9eb82baa..222a047cc145 100644
--- a/include/linux/ktime.h
+++ b/include/linux/ktime.h
@@ -266,4 +266,19 @@ static inline u64 ktime_to_ns(const ktime_t kt)
 
 #endif
 
+/*
+ * The resolution of the clocks. The resolution value is returned in
+ * the clock_getres() system call to give application programmers an
+ * idea of the (in)accuracy of timers. Timer values are rounded up to
+ * this resolution values.
+ */
+#define KTIME_REALTIME_RES      (NSEC_PER_SEC/HZ)
+#define KTIME_MONOTONIC_RES     (NSEC_PER_SEC/HZ)
+
+/* Get the monotonic time in timespec format: */
+extern void ktime_get_ts(struct timespec *ts);
+
+/* Get the real (wall-) time in timespec format: */
+#define ktime_get_real_ts(ts)   getnstimeofday(ts)
+
 #endif