Add options to not apply leap seconds in kernel.

Add kernel_leap option for ptp4l and -x option for phc2sys to disable
setting of the STA_INS/STA_DEL bit to slowly correct the one-second
offset by servo.

Signed-off-by: Miroslav Lichvar <[email protected]>

clock.c

@@ -79,6 +79,7 @@ struct clock {
 	int freq_est_interval;
 	int utc_timescale;
 	int leap_set;
+	int kernel_leap;
 	enum servo_state servo_state;
 	tmv_t master_offset;
 	tmv_t path_delay;
@@ -498,7 +499,8 @@ static int clock_utc_correct(struct clock *c, tmv_t ingress)
 		clock_leap = leap_second_status(ts, c->leap_set,
 						&leap, &utc_offset);
 		if (c->leap_set != clock_leap) {
-			clockadj_set_leap(c->clkid, clock_leap);
+			if (c->kernel_leap)
+				clockadj_set_leap(c->clkid, clock_leap);
 			c->leap_set = clock_leap;
 		}
 	}
@@ -559,6 +561,7 @@ struct clock *clock_create(int phc_index, struct interface *iface, int count,
 
 	c->free_running = dds->free_running;
 	c->freq_est_interval = dds->freq_est_interval;
+	c->kernel_leap = dds->kernel_leap;
 	c->desc = dds->clock_desc;
 
 	if (c->free_running) {

config.c

@@ -383,6 +383,11 @@ static enum parser_result parse_global_setting(const char *option,
 			return BAD_VALUE;
 		cfg->dds.stats_interval = val;
 
+	} else if (!strcmp(option, "kernel_leap")) {
+		if (1 != sscanf(value, "%d", &val))
+			return BAD_VALUE;
+		cfg->dds.kernel_leap = val;
+
 	} else
 		return NOT_PARSED;
 

default.cfg

@@ -33,6 +33,7 @@ tx_timestamp_retries	100
 use_syslog		1
 verbose			0
 summary_interval	0
+kernel_leap		1
 #
 # Servo Options
 #

ds.h

@@ -52,6 +52,7 @@ struct default_ds {
 	int free_running;
 	int freq_est_interval; /*log seconds*/
 	int stats_interval; /*log seconds*/
+	int kernel_leap;
 	struct clock_description clock_desc;
 };
 

gPTP.cfg

@@ -32,6 +32,7 @@ tx_timestamp_retries	100
 use_syslog		1
 verbose			0
 summary_interval	0
+kernel_leap		1
 #
 # Servo options
 #

phc2sys.8

@@ -31,6 +31,8 @@ phc2sys \- synchronize two clocks
 ] [
 .B \-w
 ] [
+.B \-x
+] [
 .BI \-l " print-level"
 ] [
 .B \-m
@@ -127,6 +129,13 @@ option is not used, also keep the offset between the slave and master
 times updated according to the currentUtcOffset value obtained from ptp4l and
 the direction of the clock synchronization.
 .TP
+.B \-x
+When a leap second is announced, don't apply it in the kernel by stepping the
+clock, but let the servo correct the one-second offset slowly by changing the
+clock frequency (unless the
+.B \-S
+option is used).
+.TP
 .BI \-l " print-level"
 Set the maximum syslog level of messages which should be printed or sent to
 the system logger. The default is 6 (LOG_INFO).

phc2sys.c

@@ -124,6 +124,7 @@ struct clock {
 	int sync_offset_direction;
 	int leap;
 	int leap_set;
+	int kernel_leap;
 	struct pmc *pmc;
 	int pmc_ds_idx;
 	int pmc_ds_requested;
@@ -500,7 +501,7 @@ static int update_sync_offset(struct clock *clock, int64_t offset, uint64_t ts)
 
 	if (clock->leap_set != clock_leap) {
 		/* Only the system clock can leap. */
-		if (clock->clkid == CLOCK_REALTIME)
+		if (clock->clkid == CLOCK_REALTIME && clock->kernel_leap)
 			clockadj_set_leap(clock->clkid, clock_leap);
 		clock->leap_set = clock_leap;
 	}
@@ -525,6 +526,7 @@ static void usage(char *progname)
 		" -O [offset]    slave-master time offset (0)\n"
 		" -u [num]       number of clock updates in summary stats (0)\n"
 		" -w             wait for ptp4l\n"
+		" -x             apply leap seconds by servo instead of kernel\n"
 		" -h             prints this message and exits\n"
 		" -v             prints the software version and exits\n"
 		"\n",
@@ -542,6 +544,7 @@ int main(int argc, char *argv[])
 	struct clock dst_clock = {
 		.clkid = CLOCK_REALTIME,
 		.servo_state = SERVO_UNLOCKED,
+		.kernel_leap = 1,
 	};
 
 	configured_pi_kp = KP;
@@ -551,7 +554,7 @@ int main(int argc, char *argv[])
 	progname = strrchr(argv[0], '/');
 	progname = progname ? 1+progname : argv[0];
 	while (EOF != (c = getopt(argc, argv,
-				  "c:d:hs:P:I:S:R:N:O:i:u:wl:mqv"))) {
+				  "c:d:hs:P:I:S:R:N:O:i:u:wxl:mqv"))) {
 		switch (c) {
 		case 'c':
 			dst_clock.clkid = clock_open(optarg);
@@ -596,6 +599,9 @@ int main(int argc, char *argv[])
 		case 'w':
 			wait_sync = 1;
 			break;
+		case 'x':
+			dst_clock.kernel_leap = 0;
+			break;
 		case 'l':
 			print_level = atoi(optarg);
 			break;

ptp4l.8

@@ -340,6 +340,14 @@ empty string.
 .B manufacturerIdentity
 The manufacturer id which should be an OUI owned by the manufacturer.
 The default is 00:00:00.
+.TP
+.B kernel_leap
+When a leap second is announced, let the kernel apply it by stepping the clock
+instead of correcting the one-second offset with servo, which would correct the
+one-second offset slowly by changing the clock frequency (unless the
+.B pi_offset_const
+option is set to correct such offset by stepping).
+Relevant only with software time stamping. The default is 1 (enabled).
 
 .SH SEE ALSO
 .BR pmc (8),

ptp4l.c

@@ -53,6 +53,7 @@ static struct config cfg_settings = {
 		.free_running = 0,
 		.freq_est_interval = 1,
 		.stats_interval = 0,
+		.kernel_leap = 1,
 		.clock_desc = {
 			.productDescription = {
 				.max_symbols = 64,