summaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
-rw-r--r--include/linux/time.h2
-rw-r--r--init/main.c1
-rw-r--r--kernel/Makefile1
-rw-r--r--kernel/time/clocksource.c4
-rw-r--r--kernel/timer.c93
5 files changed, 86 insertions, 15 deletions
diff --git a/include/linux/time.h b/include/linux/time.h
index 0cd696c..88d3b81 100644
--- a/include/linux/time.h
+++ b/include/linux/time.h
@@ -77,6 +77,8 @@ extern struct timespec xtime;
extern struct timespec wall_to_monotonic;
extern seqlock_t xtime_lock;
+void timekeeping_init(void);
+
static inline unsigned long get_seconds(void)
{
return xtime.tv_sec;
diff --git a/init/main.c b/init/main.c
index f715b9b..9a970d3 100644
--- a/init/main.c
+++ b/init/main.c
@@ -490,6 +490,7 @@ asmlinkage void __init start_kernel(void)
hrtimers_init();
softirq_init();
time_init();
+ timekeeping_init();
/*
* HACK ALERT! This is early. We're enabling the console before
diff --git a/kernel/Makefile b/kernel/Makefile
index f6ef00f..bc4b8a7 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -10,6 +10,7 @@ obj-y = sched.o fork.o exec_domain.o panic.o printk.o profile.o \
kthread.o wait.o kfifo.o sys_ni.o posix-cpu-timers.o mutex.o \
hrtimer.o
+obj-y += time/
obj-$(CONFIG_DEBUG_MUTEXES) += mutex-debug.o
obj-$(CONFIG_FUTEX) += futex.o
ifeq ($(CONFIG_COMPAT),y)
diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c
index 95dd220..4288bfa 100644
--- a/kernel/time/clocksource.c
+++ b/kernel/time/clocksource.c
@@ -56,7 +56,7 @@ static int finished_booting;
*
* Hack to avoid lots of clocksource churn at boot time
*/
-static int clocksource_done_booting(void)
+static int __init clocksource_done_booting(void)
{
finished_booting = 1;
return 0;
@@ -289,7 +289,7 @@ static struct sys_device device_clocksource = {
.cls = &clocksource_sysclass,
};
-static int init_clocksource_sysfs(void)
+static int __init init_clocksource_sysfs(void)
{
int error = sysdev_class_register(&clocksource_sysclass);
diff --git a/kernel/timer.c b/kernel/timer.c
index eb97371..524c7f6 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -792,24 +792,93 @@ u64 current_tick_length(void)
return ((u64) delta_nsec << (SHIFT_SCALE - 10)) + time_adj;
}
+/* XXX - all of this timekeeping code should be later moved to time.c */
+#include <linux/clocksource.h>
+static struct clocksource *clock; /* pointer to current clocksource */
+static cycle_t last_clock_cycle; /* cycle value at last update_wall_time */
/*
- * Using a loop looks inefficient, but "ticks" is
- * usually just one (we shouldn't be losing ticks,
- * we're doing this this way mainly for interrupt
- * latency reasons, not because we think we'll
- * have lots of lost timer ticks
+ * timekeeping_init - Initializes the clocksource and common timekeeping values
*/
-static void update_wall_time(unsigned long ticks)
+void __init timekeeping_init(void)
{
- do {
- ticks--;
+ unsigned long flags;
+
+ write_seqlock_irqsave(&xtime_lock, flags);
+ clock = get_next_clocksource();
+ calculate_clocksource_interval(clock, tick_nsec);
+ last_clock_cycle = read_clocksource(clock);
+ ntp_clear();
+ write_sequnlock_irqrestore(&xtime_lock, flags);
+}
+
+
+/*
+ * timekeeping_resume - Resumes the generic timekeeping subsystem.
+ * @dev: unused
+ *
+ * This is for the generic clocksource timekeeping.
+ * xtime/wall_to_monotonic/jiffies/wall_jiffies/etc are
+ * still managed by arch specific suspend/resume code.
+ */
+static int timekeeping_resume(struct sys_device *dev)
+{
+ unsigned long flags;
+
+ write_seqlock_irqsave(&xtime_lock, flags);
+ /* restart the last cycle value */
+ last_clock_cycle = read_clocksource(clock);
+ write_sequnlock_irqrestore(&xtime_lock, flags);
+ return 0;
+}
+
+/* sysfs resume/suspend bits for timekeeping */
+static struct sysdev_class timekeeping_sysclass = {
+ .resume = timekeeping_resume,
+ set_kset_name("timekeeping"),
+};
+
+static struct sys_device device_timer = {
+ .id = 0,
+ .cls = &timekeeping_sysclass,
+};
+
+static int __init timekeeping_init_device(void)
+{
+ int error = sysdev_class_register(&timekeeping_sysclass);
+ if (!error)
+ error = sysdev_register(&device_timer);
+ return error;
+}
+
+device_initcall(timekeeping_init_device);
+
+/*
+ * update_wall_time - Uses the current clocksource to increment the wall time
+ *
+ * Called from the timer interrupt, must hold a write on xtime_lock.
+ */
+static void update_wall_time(void)
+{
+ cycle_t now, offset;
+
+ now = read_clocksource(clock);
+ offset = (now - last_clock_cycle)&clock->mask;
+
+ /* normally this loop will run just once, however in the
+ * case of lost or late ticks, it will accumulate correctly.
+ */
+ while (offset > clock->interval_cycles) {
+ /* accumulate one interval */
+ last_clock_cycle += clock->interval_cycles;
+ offset -= clock->interval_cycles;
+
update_wall_time_one_tick();
if (xtime.tv_nsec >= 1000000000) {
xtime.tv_nsec -= 1000000000;
xtime.tv_sec++;
second_overflow();
}
- } while (ticks);
+ }
}
/*
@@ -915,10 +984,8 @@ static inline void update_times(void)
unsigned long ticks;
ticks = jiffies - wall_jiffies;
- if (ticks) {
- wall_jiffies += ticks;
- update_wall_time(ticks);
- }
+ wall_jiffies += ticks;
+ update_wall_time();
calc_load(ticks);
}
OpenPOWER on IntegriCloud