Decouple servo state from automotive profile.

The logic for the Automotive Profile added a message interval update
mechanism that triggers whenever the servo enters the "stable locked"
state.  This SERVO_LOCKED_STABLE state is active when the
configuration option servo_offset_threshold is non-zero and
servo_offset_threshold criteria is satisfied.

However, in general, the state of the servo can and should be
independent of any profile specific optional behavior.  In particular,
the "stable locked" state will be used in the future to trigger other
kinds useful logic.  For example, an upcoming write phase mode feature
would like to take advantage of the SERVO_LOCKED_STABLE state to
trigger its activation.

This patch introduces a proper configuration option to enable
transmission of the message interval request that is specific to the
Automotive Profile.

Signed-off-by: Vincent Cheng <vincent.cheng.xh@renesas.com>
Signed-off-by: Richard Cochran <richardcochran@gmail.com>

config.c

@@ -271,6 +271,7 @@ struct config_item config_tab[] = {
 	GLOB_ITEM_STR("manufacturerIdentity", "00:00:00"),
 	GLOB_ITEM_INT("max_frequency", 900000000, 0, INT_MAX),
 	PORT_ITEM_INT("min_neighbor_prop_delay", -20000000, INT_MIN, -1),
+	PORT_ITEM_INT("msg_interval_request", 0, 0, 1),
 	PORT_ITEM_INT("neighborPropDelayThresh", 20000000, 0, INT_MAX),
 	PORT_ITEM_INT("net_sync_monitor", 0, 0, 1),
 	PORT_ITEM_ENU("network_transport", TRANS_UDP_IPV4, nw_trans_enu),

configs/automotive-slave.cfg

@@ -33,5 +33,6 @@ ignore_source_id	1
 step_threshold          1
 operLogSyncInterval     0
 operLogPdelayReqInterval 2
+msg_interval_request     1
 servo_offset_threshold   30
 servo_num_offset_values  10

configs/default.cfg

@@ -77,6 +77,7 @@ max_frequency		900000000
 clock_servo		pi
 sanity_freq_limit	200000000
 ntpshm_segment		0
+msg_interval_request	0
 servo_num_offset_values 10
 servo_offset_threshold  0
 #

port.c

@@ -1131,6 +1131,30 @@ static void port_slave_priority_warning(struct port *p)
 	pr_warning("port %hu: defaultDS.priority1 probably misconfigured", n);
 }
 
+static void message_interval_request(struct port *p,
+				     enum servo_state last_state,
+				     Integer8 sync_interval)
+{
+	if (!p->msg_interval_request)
+		return;
+
+	if (last_state == SERVO_LOCKED) {
+		p->logPdelayReqInterval = p->operLogPdelayReqInterval;
+		p->logSyncInterval = p->operLogSyncInterval;
+		port_tx_interval_request(p, SIGNAL_NO_CHANGE,
+					 p->logSyncInterval,
+					 SIGNAL_NO_CHANGE);
+		port_dispatch(p, EV_MASTER_CLOCK_SELECTED, 0);
+	} else if (sync_interval != p->operLogSyncInterval) {
+		/*
+		 * The most likely reason for this to happen is the
+		 * master daemon re-initialized due to some fault.
+		 */
+		servo_reset(clock_servo(p->clock));
+		port_dispatch(p, EV_SYNCHRONIZATION_FAULT, 0);
+	}
+}
+
 static void port_synchronize(struct port *p,
 			     tmv_t ingress_ts,
 			     struct timestamp origin_ts,
@@ -1174,21 +1198,7 @@ static void port_synchronize(struct port *p,
 		port_dispatch(p, EV_MASTER_CLOCK_SELECTED, 0);
 		break;
 	case SERVO_LOCKED_STABLE:
-		if (last_state == SERVO_LOCKED) {
+		message_interval_request(p, last_state, sync_interval);
-			p->logPdelayReqInterval = p->operLogPdelayReqInterval;
-			p->logSyncInterval = p->operLogSyncInterval;
-			port_tx_interval_request(p, SIGNAL_NO_CHANGE,
-						 p->logSyncInterval,
-						 SIGNAL_NO_CHANGE);
-			port_dispatch(p, EV_MASTER_CLOCK_SELECTED, 0);
-		} else if (sync_interval != p->operLogSyncInterval) {
-			/*
-			 * The most likely reason for this to happen is the
-			 * master daemon re-initialized due to some fault.
-			 */
-			servo_reset(clock_servo(p->clock));
-			port_dispatch(p, EV_SYNCHRONIZATION_FAULT, 0);
-		}
 		break;
 	}
 }
@@ -3029,6 +3039,7 @@ struct port *port_open(const char *phc_device,
 	p->announce_span = transport == TRANS_UDS ? 0 : ANNOUNCE_SPAN;
 	p->follow_up_info = config_get_int(cfg, p->name, "follow_up_info");
 	p->freq_est_interval = config_get_int(cfg, p->name, "freq_est_interval");
+	p->msg_interval_request = config_get_int(cfg, p->name, "msg_interval_request");
 	p->net_sync_monitor = config_get_int(cfg, p->name, "net_sync_monitor");
 	p->path_trace_enabled = config_get_int(cfg, p->name, "path_trace_enabled");
 	p->tc_spanning_tree = config_get_int(cfg, p->name, "tc_spanning_tree");

port_private.h

@@ -128,6 +128,7 @@ struct port {
 	int                 hybrid_e2e;
 	int                 master_only;
 	int                 match_transport_specific;
+	int                 msg_interval_request;
 	int                 min_neighbor_prop_delay;
 	int                 net_sync_monitor;
 	int                 path_trace_enabled;

ptp4l.8

@@ -162,11 +162,12 @@ accuracy of the local clock. It's specified as a power of two in seconds.
 The default is 0 (1 second).
 .TP
 .B operLogSyncInterval
-The mean time interval between Sync messages. This value is only used by the
+The Sync message interval to be requested once the clock enters the
-slave device when interval_update_timer is enabled. Slave will send this
+SERVO_LOCKED_STABLE state.  If the 'msg_interval_request' option is
-interval to the master to switch to. This is done via a signaling message after
+set, then the local slave port will request the remote master to
-interval_update_timer expires. It's specified as a power of two in seconds. The
+switch to the given message rate via a signaling message containing a
-default value is 0 (1 second).
+Message interval request TLV.  This option is specified as a power of
+two in seconds, and default value is 0 (1 second).
 .TP
 .B logMinDelayReqInterval
 The minimum permitted mean time interval between Delay_Req messages. A shorter
@@ -180,11 +181,11 @@ specified as a power of two in seconds.
 The default is 0 (1 second).
 .TP
 .B operLogPdelayReqInterval
-The mean time interval between Pdelay Request messages. This value is only used
+The Pdelay Request messages interval to be used once the clock enters
-by the slave device when interval_update_timer is enabled. Slave will switch to
+the SERVO_LOCKED_STABLE state.  If the 'msg_interval_request' option
-the interval specified by this config option after the interval_update_timer
+is set, then the local slave port will adopt this rate when the local
-expires. It's specified as a power of two in seconds. The default value is 0 (1
+clock enters the "locked stable" state.  This option is specified as a
-second).
+power of two in seconds, and the default value is 0 (1 second).
 .TP
 .B inhibit_delay_req
 Don't send any delay requests. This will need the asCapable config option to be
@@ -740,21 +741,28 @@ messages. This is useful when the announce messages are disabled in the master
 and the slave does not have any way to know it's identity. The default is 0
 (disabled).
 .TP
+.B msg_interval_request
+This option, when set, will trigger an adjustment to the Sync and peer
+delay request message intervals when the clock servo transitions into
+the SERVO_LOCKED_STABLE state.  The Sync interval will be adjusted via
+the signaling mechanism while the pdelay request interval is simply
+adjusted locally.  The values to use for the new Sync and peer delay
+request intervals are specified by the operLogSyncInterval and
+operLogPdelayReqInterval options, respectively.
+The default value of msg_interval_request is 0 (disabled).
+.TP
 .B servo_num_offset_values
-The number of offset values calculated in previously received Sync messages to
+The number of offset values considered in order to transition from the
-consider when adjusting the Sync and Pdelay request intervals. More information
+SERVO_LOCKED to the SERVO_LOCKED_STABLE state.
-provided in the description of 'offset_threshold'. The default value is 10.
+The transition occurs once the last 'servo_num_offset_values' offsets
+are all below the 'servo_offset_threshold' value.
+The default value is 10.
 .TP
 .B servo_offset_threshold
-This value is used by the slave for adjusting the intervals for Sync and Pdelay
+The offset threshold used in order to transition from the SERVO_LOCKED
-request messages. The slave will check the last 'num_offset_values' offsets and
+to the SERVO_LOCKED_STABLE state.  The transition occurs once the last
-if all those offsets are less than the offset_threshold, it will adjust both
+'servo_num_offset_values' offsets are all below the threshold value.
-the intervals. The Sync interval is adjusted via the signaling mechanism and
+The default value of offset_threshold is 0 (disabled).
-the pdelay request interval is just adjusted locally. The new values to use for
-sync message intervals and pdelay request intervals can be indicated by
-operLogSyncInterval and operLogPdelayReqInterval respectively. This mechanism
-is currently only supported when BMCA == 'noop'. The default
-value of offset_threshold is 0 (disabled).
 
 .SH UNICAST DISCOVERY OPTIONS