integ/base/linuxptp/centos/patches/0006-Add-option-to-disable-default-port-selection-in-phc2.patch

From 3a6de7b6208ccc64a20474db15abaac08e99d10b Mon Sep 17 00:00:00 2001
Message-Id: <3a6de7b6208ccc64a20474db15abaac08e99d10b.1630418391.git.Jim.Somerville@windriver.com>
In-Reply-To: <0389752e3aecf8d2b2743f16ce1408a58088bea9.1630418391.git.Jim.Somerville@windriver.com>
References: <0389752e3aecf8d2b2743f16ce1408a58088bea9.1630418391.git.Jim.Somerville@windriver.com>
From: Cole Walker <cole.walker@windriver.com>
Date: Wed, 23 Jun 2021 11:14:41 -0400
Subject: [PATCH 6/6] Add option to disable default port selection in phc2sys

This change serves to address an issue in phc2sys
where the local ptp clocks are not synced together properly if the local
time is far behind the reference time. This issue occurs when phc2sys
starts and there is no client port currently synced to a grandmaster. In
the original behaviour, phc2sys selects the first configured port and
proceeds to sync all of the other clocks to it by performing the
first_step operation.

Then ptp4l will evenually lock to the Grandmaster clock, and that
single port will have its time updated to the correct value, but
phc2sys has already performed the first_step operation and will not
step the other clocks again.

This solution provides an option to disable the selection of a
default port by phc2sys. When no default port is selected, phc2sys waits
for ptp4l to sync to the Grandmaster before bringing the other clocks
into sync with the first_step operation.

This option is configured via the default_sync
parameter or the -D flag. The default_sync parameter is set to on by
default in order to keep the behaviour the same as upstream linuxptp
but can be configured by users via
system service-parameter-add ptp global default_sync=0

Signed-off-by: Jim Somerville <Jim.Somerville@windriver.com>
---
 config.c  |  1 +
 phc2sys.c | 15 ++++++++++++---
 2 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/config.c b/config.c
index ef5e833..cab7e4f 100644
--- a/config.c
+++ b/config.c
@@ -333,6 +333,7 @@ struct config_item config_tab[] = {
 	GLOB_ITEM_INT("utc_offset", CURRENT_UTC_OFFSET, 0, INT_MAX),
 	GLOB_ITEM_INT("verbose", 0, 0, 1),
 	GLOB_ITEM_INT("write_phase_mode", 0, 0, 1),
+	GLOB_ITEM_INT("default_sync", 1, 0, 1),
 };
 
 static struct unicast_master_table *current_uc_mtab;
diff --git a/phc2sys.c b/phc2sys.c
index a36cbe0..44d6872 100644
--- a/phc2sys.c
+++ b/phc2sys.c
@@ -120,6 +120,7 @@ struct phc2sys_private {
 	LIST_HEAD(clock_head, clock) clocks;
 	LIST_HEAD(dst_clock_head, clock) dst_clocks;
 	struct clock *master;
+	int default_sync;
 };
 
 static struct config *phc2sys_config;
@@ -437,7 +438,7 @@ static void reconfigure(struct phc2sys_private *priv)
 		}
 		last = c;
 	}
-	if (dst_cnt > 1 && !src) {
+	if (dst_cnt > 1 && !src && priv->default_sync) {
 		if (!rt || rt->dest_only) {
 			priv->master = last;
 			/* Reset to original state in next reconfiguration. */
@@ -1344,6 +1345,7 @@ static void usage(char *progname)
 		" -N [num]       number of master clock readings per update (5)\n"
 		" -L [limit]     sanity frequency limit in ppb (200000000)\n"
 		" -M [num]       NTP SHM segment number (0)\n"
+		" -D [num]       fall back to default clock in automatic mode (1)\n"
 		" -u [num]       number of clock updates in summary stats (0)\n"
 		" -n [num]       domain number (0)\n"
 		" -x             apply leap seconds by servo instead of kernel\n"
@@ -1364,7 +1366,7 @@ int main(int argc, char *argv[])
 	struct clock *src, *dst;
 	struct config *cfg;
 	struct option *opts;
-	int autocfg = 0, c, domain_number = 0, index, ntpshm_segment;
+	int autocfg = 0, c, domain_number = 0, default_sync = 1, index, ntpshm_segment;
 	int pps_fd = -1, print_level = LOG_INFO, r = -1, rt = 0, wait_sync = 0;
 	double phc_rate, tmp;
 	struct phc2sys_private priv = {
@@ -1388,7 +1390,7 @@ int main(int argc, char *argv[])
 	progname = strrchr(argv[0], '/');
 	progname = progname ? 1+progname : argv[0];
 	while (EOF != (c = getopt_long(argc, argv,
-				"arc:d:f:s:E:P:I:S:F:R:N:O:L:M:i:u:wn:xz:l:t:mqvh",
+				"arc:d:f:s:E:P:I:S:F:R:N:O:L:M:D:i:u:wn:xz:l:t:mqvh",
 				opts, &index))) {
 		switch (c) {
 		case 0:
@@ -1540,6 +1542,12 @@ int main(int argc, char *argv[])
 			version_show(stdout);
 			config_destroy(cfg);
 			return 0;
+		case 'D':
+			if (get_arg_val_i(c, optarg, &default_sync, 0, 1) ||
+			config_set_int(cfg, "default_sync", default_sync)) {
+				goto end;
+			}
+			break;
 		case 'h':
 			usage(progname);
 			config_destroy(cfg);
@@ -1588,6 +1596,7 @@ int main(int argc, char *argv[])
 	}
 	priv.kernel_leap = config_get_int(cfg, NULL, "kernel_leap");
 	priv.sanity_freq_limit = config_get_int(cfg, NULL, "sanity_freq_limit");
+	priv.default_sync = config_get_int(cfg, NULL, "default_sync");
 
 	if (autocfg) {
 		if (init_pmc(cfg, &priv))
-- 
2.29.2