X-Git-Url: https://git.karo-electronics.de/?a=blobdiff_plain;f=kernel%2Ftime%2Ftimekeeping.c;h=fb0f46fa1ecd0fc09b656e2759ff990372faacb3;hb=89ae400e3f57c9d60cd4da3501bb09c1502b723c;hp=dfdab1cefe1e3720ac9ceae45dac97b1a3f5814f;hpb=23ce72117c714baab794e66c8daf343bf6a912bf;p=karo-tx-linux.git

diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index dfdab1cefe1e..fb0f46fa1ecd 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -18,6 +18,7 @@
 #include <linux/jiffies.h>
 #include <linux/time.h>
 #include <linux/tick.h>
+#include <linux/stop_machine.h>
 
 /* Structure holding internal timekeeping values. */
 struct timekeeper {
@@ -41,6 +42,8 @@ struct timekeeper {
 	/* Shift conversion between clock shifted nano seconds and
 	 * ntp shifted nano seconds. */
 	int	ntp_error_shift;
+	/* NTP adjusted clock multiplier */
+	u32	mult;
 };
 
 struct timekeeper timekeeper;
@@ -66,8 +69,8 @@ static void timekeeper_setup_internals(struct clocksource *clock)
 	/* Do the ns -> cycle conversion first, using original mult */
 	tmp = NTP_INTERVAL_LENGTH;
 	tmp <<= clock->shift;
-	tmp += clock->mult_orig/2;
-	do_div(tmp, clock->mult_orig);
+	tmp += clock->mult/2;
+	do_div(tmp, clock->mult);
 	if (tmp == 0)
 		tmp = 1;
 
@@ -77,13 +80,54 @@ static void timekeeper_setup_internals(struct clocksource *clock)
 	/* Go back from cycles -> shifted ns */
 	timekeeper.xtime_interval = (u64) interval * clock->mult;
 	timekeeper.raw_interval =
-		((u64) interval * clock->mult_orig) >> clock->shift;
+		((u64) interval * clock->mult) >> clock->shift;
 
 	timekeeper.xtime_nsec = 0;
 	timekeeper.shift = clock->shift;
 
 	timekeeper.ntp_error = 0;
 	timekeeper.ntp_error_shift = NTP_SCALE_SHIFT - clock->shift;
+
+	/*
+	 * The timekeeper keeps its own mult values for the currently
+	 * active clocksource. These value will be adjusted via NTP
+	 * to counteract clock drifting.
+	 */
+	timekeeper.mult = clock->mult;
+}
+
+/* Timekeeper helper functions. */
+static inline s64 timekeeping_get_ns(void)
+{
+	cycle_t cycle_now, cycle_delta;
+	struct clocksource *clock;
+
+	/* read clocksource: */
+	clock = timekeeper.clock;
+	cycle_now = clock->read(clock);
+
+	/* calculate the delta since the last update_wall_time: */
+	cycle_delta = (cycle_now - clock->cycle_last) & clock->mask;
+
+	/* return delta convert to nanoseconds using ntp adjusted mult. */
+	return clocksource_cyc2ns(cycle_delta, timekeeper.mult,
+				  timekeeper.shift);
+}
+
+static inline s64 timekeeping_get_ns_raw(void)
+{
+	cycle_t cycle_now, cycle_delta;
+	struct clocksource *clock;
+
+	/* read clocksource: */
+	clock = timekeeper.clock;
+	cycle_now = clock->read(clock);
+
+	/* calculate the delta since the last update_wall_time: */
+	cycle_delta = (cycle_now - clock->cycle_last) & clock->mask;
+
+	/* return delta convert to nanoseconds using ntp adjusted mult. */
+	return clocksource_cyc2ns(cycle_delta, clock->mult, clock->shift);
 }
 
 /*
@@ -110,7 +154,7 @@ __cacheline_aligned_in_smp DEFINE_SEQLOCK(xtime_lock);
  */
 struct timespec xtime __attribute__ ((aligned (16)));
 struct timespec wall_to_monotonic __attribute__ ((aligned (16)));
-static unsigned long total_sleep_time;		/* seconds */
+static struct timespec total_sleep_time;
 
 /*
  * The raw monotonic time for the CLOCK_MONOTONIC_RAW posix clock.
@@ -136,6 +180,7 @@ void timekeeping_leap_insert(int leapsecond)
 }
 
 #ifdef CONFIG_GENERIC_TIME
+
 /**
  * timekeeping_forward_now - update clock to the current time
  *
@@ -154,14 +199,15 @@ static void timekeeping_forward_now(void)
 	cycle_delta = (cycle_now - clock->cycle_last) & clock->mask;
 	clock->cycle_last = cycle_now;
 
-	nsec = clocksource_cyc2ns(cycle_delta, clock->mult, clock->shift);
+	nsec = clocksource_cyc2ns(cycle_delta, timekeeper.mult,
+				  timekeeper.shift);
 
 	/* If arch requires, add in gettimeoffset() */
 	nsec += arch_gettimeoffset();
 
 	timespec_add_ns(&xtime, nsec);
 
-	nsec = clocksource_cyc2ns(cycle_delta, clock->mult_orig, clock->shift);
+	nsec = clocksource_cyc2ns(cycle_delta, clock->mult, clock->shift);
 	timespec_add_ns(&raw_time, nsec);
 }
 
@@ -173,8 +219,6 @@ static void timekeeping_forward_now(void)
  */
 void getnstimeofday(struct timespec *ts)
 {
-	cycle_t cycle_now, cycle_delta;
-	struct clocksource *clock;
 	unsigned long seq;
 	s64 nsecs;
 
@@ -184,17 +228,7 @@ void getnstimeofday(struct timespec *ts)
 		seq = read_seqbegin(&xtime_lock);
 
 		*ts = xtime;
-
-		/* read clocksource: */
-		clock = timekeeper.clock;
-		cycle_now = clock->read(clock);
-
-		/* calculate the delta since the last update_wall_time: */
-		cycle_delta = (cycle_now - clock->cycle_last) & clock->mask;
-
-		/* convert to nanoseconds: */
-		nsecs = clocksource_cyc2ns(cycle_delta, clock->mult,
-					   clock->shift);
+		nsecs = timekeeping_get_ns();
 
 		/* If arch requires, add in gettimeoffset() */
 		nsecs += arch_gettimeoffset();
@@ -208,8 +242,6 @@ EXPORT_SYMBOL(getnstimeofday);
 
 ktime_t ktime_get(void)
 {
-	cycle_t cycle_now, cycle_delta;
-	struct clocksource *clock;
 	unsigned int seq;
 	s64 secs, nsecs;
 
@@ -219,17 +251,7 @@ ktime_t ktime_get(void)
 		seq = read_seqbegin(&xtime_lock);
 		secs = xtime.tv_sec + wall_to_monotonic.tv_sec;
 		nsecs = xtime.tv_nsec + wall_to_monotonic.tv_nsec;
-
-		/* read clocksource: */
-		clock = timekeeper.clock;
-		cycle_now = clock->read(clock);
-
-		/* calculate the delta since the last update_wall_time: */
-		cycle_delta = (cycle_now - clock->cycle_last) & clock->mask;
-
-		/* convert to nanoseconds: */
-		nsecs += clocksource_cyc2ns(cycle_delta, clock->mult,
-					    clock->shift);
+		nsecs += timekeeping_get_ns();
 
 	} while (read_seqretry(&xtime_lock, seq));
 	/*
@@ -250,8 +272,6 @@ EXPORT_SYMBOL_GPL(ktime_get);
  */
 void ktime_get_ts(struct timespec *ts)
 {
-	cycle_t cycle_now, cycle_delta;
-	struct clocksource *clock;
 	struct timespec tomono;
 	unsigned int seq;
 	s64 nsecs;
@@ -262,17 +282,7 @@ void ktime_get_ts(struct timespec *ts)
 		seq = read_seqbegin(&xtime_lock);
 		*ts = xtime;
 		tomono = wall_to_monotonic;
-
-		/* read clocksource: */
-		clock = timekeeper.clock;
-		cycle_now = clock->read(clock);
-
-		/* calculate the delta since the last update_wall_time: */
-		cycle_delta = (cycle_now - clock->cycle_last) & clock->mask;
-
-		/* convert to nanoseconds: */
-		nsecs = clocksource_cyc2ns(cycle_delta, clock->mult,
-					   clock->shift);
+		nsecs = timekeeping_get_ns();
 
 	} while (read_seqretry(&xtime_lock, seq));
 
@@ -343,43 +353,40 @@ EXPORT_SYMBOL(do_settimeofday);
  *
  * Accumulates current time interval and initializes new clocksource
  */
-static void change_clocksource(void)
+static int change_clocksource(void *data)
 {
 	struct clocksource *new, *old;
 
-	new = clocksource_get_next();
-
-	if (!new || timekeeper.clock == new)
-		return;
+	new = (struct clocksource *) data;
 
 	timekeeping_forward_now();
+	if (!new->enable || new->enable(new) == 0) {
+		old = timekeeper.clock;
+		timekeeper_setup_internals(new);
+		if (old->disable)
+			old->disable(old);
+	}
+	return 0;
+}
 
-	if (new->enable && !new->enable(new))
+/**
+ * timekeeping_notify - Install a new clock source
+ * @clock:		pointer to the clock source
+ *
+ * This function is called from clocksource.c after a new, better clock
+ * source has been registered. The caller holds the clocksource_mutex.
+ */
+void timekeeping_notify(struct clocksource *clock)
+{
+	if (timekeeper.clock == clock)
 		return;
-	/*
-	 * The frequency may have changed while the clocksource
-	 * was disabled. If so the code in ->enable() must update
-	 * the mult value to reflect the new frequency. Make sure
-	 * mult_orig follows this change.
-	 */
-	new->mult_orig = new->mult;
-
-	old = timekeeper.clock;
-	timekeeper_setup_internals(new);
-
-	/*
-	 * Save mult_orig in mult so that the value can be restored
-	 * regardless if ->enable() updates the value of mult or not.
-	 */
-	old->mult = old->mult_orig;
-	if (old->disable)
-		old->disable(old);
-
+	stop_machine(change_clocksource, clock, NULL);
 	tick_clock_notify();
 }
+
 #else /* GENERIC_TIME */
+
 static inline void timekeeping_forward_now(void) { }
-static inline void change_clocksource(void) { }
 
 /**
  * ktime_get - get the monotonic time in ktime_t format
@@ -420,6 +427,7 @@ void ktime_get_ts(struct timespec *ts)
 				ts->tv_nsec + tomono.tv_nsec);
 }
 EXPORT_SYMBOL_GPL(ktime_get_ts);
+
 #endif /* !GENERIC_TIME */
 
 /**
@@ -447,23 +455,10 @@ void getrawmonotonic(struct timespec *ts)
 {
 	unsigned long seq;
 	s64 nsecs;
-	cycle_t cycle_now, cycle_delta;
-	struct clocksource *clock;
 
 	do {
 		seq = read_seqbegin(&xtime_lock);
-
-		/* read clocksource: */
-		clock = timekeeper.clock;
-		cycle_now = clock->read(clock);
-
-		/* calculate the delta since the last update_wall_time: */
-		cycle_delta = (cycle_now - clock->cycle_last) & clock->mask;
-
-		/* convert to nanoseconds: */
-		nsecs = clocksource_cyc2ns(cycle_delta, clock->mult_orig,
-					   clock->shift);
-
+		nsecs = timekeeping_get_ns_raw();
 		*ts = raw_time;
 
 	} while (read_seqretry(&xtime_lock, seq));
@@ -492,17 +487,33 @@ int timekeeping_valid_for_hres(void)
 }
 
 /**
- * read_persistent_clock -  Return time in seconds from the persistent clock.
+ * read_persistent_clock -  Return time from the persistent clock.
  *
  * Weak dummy function for arches that do not yet support it.
- * Returns seconds from epoch using the battery backed persistent clock.
- * Returns zero if unsupported.
+ * Reads the time from the battery backed persistent clock.
+ * Returns a timespec with tv_sec=0 and tv_nsec=0 if unsupported.
  *
  *  XXX - Do be sure to remove it once all arches implement it.
  */
-unsigned long __attribute__((weak)) read_persistent_clock(void)
+void __attribute__((weak)) read_persistent_clock(struct timespec *ts)
 {
-	return 0;
+	ts->tv_sec = 0;
+	ts->tv_nsec = 0;
+}
+
+/**
+ * read_boot_clock -  Return time of the system start.
+ *
+ * Weak dummy function for arches that do not yet support it.
+ * Function to read the exact time the system has been started.
+ * Returns a timespec with tv_sec=0 and tv_nsec=0 if unsupported.
+ *
+ *  XXX - Do be sure to remove it once all arches implement it.
+ */
+void __attribute__((weak)) read_boot_clock(struct timespec *ts)
+{
+	ts->tv_sec = 0;
+	ts->tv_nsec = 0;
 }
 
 /*
@@ -512,7 +523,10 @@ void __init timekeeping_init(void)
 {
 	struct clocksource *clock;
 	unsigned long flags;
-	unsigned long sec = read_persistent_clock();
+	struct timespec now, boot;
+
+	read_persistent_clock(&now);
+	read_boot_clock(&boot);
 
 	write_seqlock_irqsave(&xtime_lock, flags);
 
@@ -521,24 +535,26 @@ void __init timekeeping_init(void)
 	clock = clocksource_default_clock();
 	if (clock->enable)
 		clock->enable(clock);
-	/* set mult_orig on enable */
-	clock->mult_orig = clock->mult;
-
 	timekeeper_setup_internals(clock);
 
-	xtime.tv_sec = sec;
-	xtime.tv_nsec = 0;
+	xtime.tv_sec = now.tv_sec;
+	xtime.tv_nsec = now.tv_nsec;
 	raw_time.tv_sec = 0;
 	raw_time.tv_nsec = 0;
+	if (boot.tv_sec == 0 && boot.tv_nsec == 0) {
+		boot.tv_sec = xtime.tv_sec;
+		boot.tv_nsec = xtime.tv_nsec;
+	}
 	set_normalized_timespec(&wall_to_monotonic,
-		-xtime.tv_sec, -xtime.tv_nsec);
+				-boot.tv_sec, -boot.tv_nsec);
 	update_xtime_cache(0);
-	total_sleep_time = 0;
+	total_sleep_time.tv_sec = 0;
+	total_sleep_time.tv_nsec = 0;
 	write_sequnlock_irqrestore(&xtime_lock, flags);
 }
 
 /* time in seconds when suspend began */
-static unsigned long timekeeping_suspend_time;
+static struct timespec timekeeping_suspend_time;
 
 /**
  * timekeeping_resume - Resumes the generic timekeeping subsystem.
@@ -551,18 +567,19 @@ static unsigned long timekeeping_suspend_time;
 static int timekeeping_resume(struct sys_device *dev)
 {
 	unsigned long flags;
-	unsigned long now = read_persistent_clock();
+	struct timespec ts;
+
+	read_persistent_clock(&ts);
 
 	clocksource_resume();
 
 	write_seqlock_irqsave(&xtime_lock, flags);
 
-	if (now && (now > timekeeping_suspend_time)) {
-		unsigned long sleep_length = now - timekeeping_suspend_time;
-
-		xtime.tv_sec += sleep_length;
-		wall_to_monotonic.tv_sec -= sleep_length;
-		total_sleep_time += sleep_length;
+	if (timespec_compare(&ts, &timekeeping_suspend_time) > 0) {
+		ts = timespec_sub(ts, timekeeping_suspend_time);
+		xtime = timespec_add_safe(xtime, ts);
+		wall_to_monotonic = timespec_sub(wall_to_monotonic, ts);
+		total_sleep_time = timespec_add_safe(total_sleep_time, ts);
 	}
 	update_xtime_cache(0);
 	/* re-base the last cycle value */
@@ -585,7 +602,7 @@ static int timekeeping_suspend(struct sys_device *dev, pm_message_t state)
 {
 	unsigned long flags;
 
-	timekeeping_suspend_time = read_persistent_clock();
+	read_persistent_clock(&timekeeping_suspend_time);
 
 	write_seqlock_irqsave(&xtime_lock, flags);
 	timekeeping_forward_now();
@@ -697,7 +714,7 @@ static void timekeeping_adjust(s64 offset)
 	} else
 		return;
 
-	timekeeper.clock->mult += adj;
+	timekeeper.mult += adj;
 	timekeeper.xtime_interval += interval;
 	timekeeper.xtime_nsec -= offset;
 	timekeeper.ntp_error -= (interval - offset) <<
@@ -789,11 +806,10 @@ void update_wall_time(void)
 	timekeeper.ntp_error +=	timekeeper.xtime_nsec <<
 				timekeeper.ntp_error_shift;
 
-	nsecs = clocksource_cyc2ns(offset, clock->mult, clock->shift);
+	nsecs = clocksource_cyc2ns(offset, timekeeper.mult, timekeeper.shift);
 	update_xtime_cache(nsecs);
 
 	/* check to see if there is a new clocksource to use */
-	change_clocksource();
 	update_vsyscall(&xtime, timekeeper.clock);
 }
 
@@ -810,9 +826,12 @@ void update_wall_time(void)
  */
 void getboottime(struct timespec *ts)
 {
-	set_normalized_timespec(ts,
-		- (wall_to_monotonic.tv_sec + total_sleep_time),
-		- wall_to_monotonic.tv_nsec);
+	struct timespec boottime = {
+		.tv_sec = wall_to_monotonic.tv_sec + total_sleep_time.tv_sec,
+		.tv_nsec = wall_to_monotonic.tv_nsec + total_sleep_time.tv_nsec
+	};
+
+	set_normalized_timespec(ts, -boottime.tv_sec, -boottime.tv_nsec);
 }
 
 /**
@@ -821,7 +840,7 @@ void getboottime(struct timespec *ts)
  */
 void monotonic_to_bootbased(struct timespec *ts)
 {
-	ts->tv_sec += total_sleep_time;
+	*ts = timespec_add_safe(*ts, total_sleep_time);
 }
 
 unsigned long get_seconds(void)
@@ -830,6 +849,10 @@ unsigned long get_seconds(void)
 }
 EXPORT_SYMBOL(get_seconds);
 
+struct timespec __current_kernel_time(void)
+{
+	return xtime_cache;
+}
 
 struct timespec current_kernel_time(void)
 {
@@ -845,3 +868,20 @@ struct timespec current_kernel_time(void)
 	return now;
 }
 EXPORT_SYMBOL(current_kernel_time);
+
+struct timespec get_monotonic_coarse(void)
+{
+	struct timespec now, mono;
+	unsigned long seq;
+
+	do {
+		seq = read_seqbegin(&xtime_lock);
+
+		now = xtime_cache;
+		mono = wall_to_monotonic;
+	} while (read_seqretry(&xtime_lock, seq));
+
+	set_normalized_timespec(&now, now.tv_sec + mono.tv_sec,
+				now.tv_nsec + mono.tv_nsec);
+	return now;
+}