telecom: Add a configuration option to use the alternate BMCA.

Signed-off-by: Richard Cochran <richardcochran@gmail.com>

bmc.h

@@ -29,6 +29,11 @@
 #define B_BETTER      -1
 #define B_BETTER_TOPO -2
 
+enum {
+	DS_CMP_IEEE1588,
+	DS_CMP_G8275,
+};
+
 /**
  * BMC state decision algorithm.
  * @param c  The local clock.

clock.c

@@ -1064,7 +1064,11 @@ struct clock *clock_create(enum clock_type type, struct config *config,
 	}
 	c->servo_state = SERVO_UNLOCKED;
 	c->servo_type = servo;
-	c->dscmp = dscmp;
+	if (config_get_int(config, NULL, "dataset_comparison") == DS_CMP_G8275) {
+		c->dscmp = telecom_dscmp;
+	} else {
+		c->dscmp = dscmp;
+	}
 	c->tsproc = tsproc_create(config_get_int(config, NULL, "tsproc_mode"),
 				  config_get_int(config, NULL, "delay_filter"),
 				  config_get_int(config, NULL, "delay_filter_length"));

config.c

@@ -22,6 +22,8 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+
+#include "bmc.h"
 #include "config.h"
 #include "ether.h"
 #include "hash.h"
@@ -133,6 +135,12 @@ static struct config_enum clock_servo_enu[] = {
 	{ NULL, 0 },
 };
 
+static struct config_enum dataset_comp_enu[] = {
+	{ "ieee1588", DS_CMP_IEEE1588 },
+	{ "G.8275.x", DS_CMP_G8275    },
+	{ NULL, 0 },
+};
+
 static struct config_enum delay_filter_enu[] = {
 	{ "moving_average", FILTER_MOVING_AVERAGE },
 	{ "moving_median",  FILTER_MOVING_MEDIAN  },
@@ -178,6 +186,7 @@ struct config_item config_tab[] = {
 	GLOB_ITEM_INT("clockAccuracy", 0xfe, 0, UINT8_MAX),
 	GLOB_ITEM_INT("clockClass", 248, 0, UINT8_MAX),
 	GLOB_ITEM_ENU("clock_servo", CLOCK_SERVO_PI, clock_servo_enu),
+	GLOB_ITEM_ENU("dataset_comparison", DS_CMP_IEEE1588, dataset_comp_enu),
 	PORT_ITEM_INT("delayAsymmetry", 0, INT_MIN, INT_MAX),
 	PORT_ITEM_ENU("delay_filter", FILTER_MOVING_MEDIAN, delay_filter_enu),
 	PORT_ITEM_INT("delay_filter_length", 10, 1, INT_MAX),

default.cfg

@@ -15,6 +15,7 @@ free_running		0
 freq_est_interval	1
 dscp_event		0
 dscp_general		0
+dataset_comparison	ieee1588
 G.8275.defaultDS.localPriority	128
 #
 # Port Data Set

gPTP.cfg

@@ -13,6 +13,7 @@ clockAccuracy		0xFE
 offsetScaledLogVariance	0xFFFF
 free_running		0
 freq_est_interval	1
+dataset_comparison	ieee1588
 G.8275.defaultDS.localPriority	128
 #
 # Port Data Set

ptp4l.8

@@ -534,6 +534,11 @@ streaming standards out there that recommend specific values for this option.
 For example 34 (AF41 PHB) in AES67 or 46 (EF PHB) in RAVENNA. The default
 is 0.
 .TP
+.B dataset_comparison
+Specifies the method to be used when comparing data sets during the
+Best Master Clock Algorithm.  The possible values are "ieee1588" and
+"G.8275.x".  The default is "ieee1588".
+.TP
 .B logging_level
 The maximum logging level of messages which should be printed.
 The default is 6 (LOG_INFO).