X-Git-Url: http://review.tizen.org/git/?a=blobdiff_plain;f=kernel%2Ftime%2Fsched_clock.c;h=313a662911b186388dfc8705676fa6b18ceeb39d;hb=1ae2c97a0a284ca73754acd2b3be33fe4f2505b2;hp=0abb364642818e4ef842ab2f3631d15cb80400f2;hpb=9df5a9b02fb59a4148bc93e0d20731c72aaffa5f;p=platform%2Fadaptation%2Frenesas_rcar%2Frenesas_kernel.git

diff --git a/kernel/time/sched_clock.c b/kernel/time/sched_clock.c
index 0abb364..313a662 100644
--- a/kernel/time/sched_clock.c
+++ b/kernel/time/sched_clock.c
@@ -116,20 +116,42 @@ static enum hrtimer_restart sched_clock_poll(struct hrtimer *hrt)
 void __init sched_clock_register(u64 (*read)(void), int bits,
 				 unsigned long rate)
 {
+	u64 res, wrap, new_mask, new_epoch, cyc, ns;
+	u32 new_mult, new_shift;
+	ktime_t new_wrap_kt;
 	unsigned long r;
-	u64 res, wrap;
 	char r_unit;
 
 	if (cd.rate > rate)
 		return;
 
 	WARN_ON(!irqs_disabled());
-	read_sched_clock = read;
-	sched_clock_mask = CLOCKSOURCE_MASK(bits);
-	cd.rate = rate;
 
 	/* calculate the mult/shift to convert counter ticks to ns. */
-	clocks_calc_mult_shift(&cd.mult, &cd.shift, rate, NSEC_PER_SEC, 3600);
+	clocks_calc_mult_shift(&new_mult, &new_shift, rate, NSEC_PER_SEC, 3600);
+
+	new_mask = CLOCKSOURCE_MASK(bits);
+
+	/* calculate how many ns until we wrap */
+	wrap = clocks_calc_max_nsecs(new_mult, new_shift, 0, new_mask);
+	new_wrap_kt = ns_to_ktime(wrap - (wrap >> 3));
+
+	/* update epoch for new counter and update epoch_ns from old counter*/
+	new_epoch = read();
+	cyc = read_sched_clock();
+	ns = cd.epoch_ns + cyc_to_ns((cyc - cd.epoch_cyc) & sched_clock_mask,
+			  cd.mult, cd.shift);
+
+	raw_write_seqcount_begin(&cd.seq);
+	read_sched_clock = read;
+	sched_clock_mask = new_mask;
+	cd.rate = rate;
+	cd.wrap_kt = new_wrap_kt;
+	cd.mult = new_mult;
+	cd.shift = new_shift;
+	cd.epoch_cyc = new_epoch;
+	cd.epoch_ns = ns;
+	raw_write_seqcount_end(&cd.seq);
 
 	r = rate;
 	if (r >= 4000000) {
@@ -141,22 +163,12 @@ void __init sched_clock_register(u64 (*read)(void), int bits,
 	} else
 		r_unit = ' ';
 
-	/* calculate how many ns until we wrap */
-	wrap = clocks_calc_max_nsecs(cd.mult, cd.shift, 0, sched_clock_mask);
-	cd.wrap_kt = ns_to_ktime(wrap - (wrap >> 3));
-
 	/* calculate the ns resolution of this counter */
-	res = cyc_to_ns(1ULL, cd.mult, cd.shift);
+	res = cyc_to_ns(1ULL, new_mult, new_shift);
+
 	pr_info("sched_clock: %u bits at %lu%cHz, resolution %lluns, wraps every %lluns\n",
 		bits, r, r_unit, res, wrap);
 
-	update_sched_clock();
-
-	/*
-	 * Ensure that sched_clock() starts off at 0ns
-	 */
-	cd.epoch_ns = 0;
-
 	/* Enable IRQ time accounting if we have a fast enough sched_clock */
 	if (irqtime > 0 || (irqtime == -1 && rate >= 1000000))
 		enable_sched_clock_irqtime();
@@ -192,7 +204,8 @@ void __init sched_clock_postinit(void)
 
 static int sched_clock_suspend(void)
 {
-	sched_clock_poll(&sched_clock_timer);
+	update_sched_clock();
+	hrtimer_cancel(&sched_clock_timer);
 	cd.suspended = true;
 	return 0;
 }
@@ -200,6 +213,7 @@ static int sched_clock_suspend(void)
 static void sched_clock_resume(void)
 {
 	cd.epoch_cyc = read_sched_clock();
+	hrtimer_start(&sched_clock_timer, cd.wrap_kt, HRTIMER_MODE_REL);
 	cd.suspended = false;
 }