host/trxcon/scheduler: process frames in advance

In order to get the transceiver more time to process bursts,
the L1 scheduler should process the frames and send the bursts
in advance (a few frames before), like OsmoBTS does. By default,
the advance value is 20 frames, but this can be adjusted using a
new command line option of trxcon '-f'.

Change-Id: Ic258a169f3554f931d6277e18ca060d029b77f32

4 files changed, 23 insertions, 5 deletions

diff --git a/src/host/trxcon/sched_trx.c b/src/host/trxcon/sched_trx.c
index b7ebfeb2..02da2412 100644
--- a/src/host/trxcon/sched_trx.c
+++ b/src/host/trxcon/sched_trx.c
@@ -75,8 +75,14 @@ static void sched_frame_clck_cb(struct trx_sched *sched)
 		if (llist_empty(&ts->tx_prims))
 			continue;
 
+		/**
+		 * Advance frame number, giving the transceiver more
+		 * time until a burst must be transmitted...
+		 */
+		fn = (sched->fn_counter_proc + sched->fn_counter_advance)
+			% GSM_HYPERFRAME;
+
 		/* Get frame from multiframe */
-		fn = sched->fn_counter_proc;
 		offset = fn % ts->mf_layout->period;
 		frame = ts->mf_layout->frames + offset;
 
@@ -103,7 +109,7 @@ static void sched_frame_clck_cb(struct trx_sched *sched)
 	}
 }
 
-int sched_trx_init(struct trx_instance *trx)
+int sched_trx_init(struct trx_instance *trx, uint32_t fn_advance)
 {
 	struct trx_sched *sched;
 
@@ -122,6 +128,9 @@ int sched_trx_init(struct trx_instance *trx)
 	sched = &trx->sched;
 	sched->data = trx;
 
+	/* Set frame counter advance */
+	sched->fn_counter_advance = fn_advance;
+
 	return 0;
 }
 
diff --git a/src/host/trxcon/sched_trx.h b/src/host/trxcon/sched_trx.h
index 9d038fbe..e1ef9244 100644
--- a/src/host/trxcon/sched_trx.h
+++ b/src/host/trxcon/sched_trx.h
@@ -246,7 +246,7 @@ const struct trx_multiframe *sched_mframe_layout(
 	enum gsm_phys_chan_config config, int tn);
 
 /* Scheduler management functions */
-int sched_trx_init(struct trx_instance *trx);
+int sched_trx_init(struct trx_instance *trx, uint32_t fn_advance);
 int sched_trx_reset(struct trx_instance *trx, int reset_clock);
 int sched_trx_shutdown(struct trx_instance *trx);
 
diff --git a/src/host/trxcon/scheduler.h b/src/host/trxcon/scheduler.h
index b025d918..f36c3b2b 100644
--- a/src/host/trxcon/scheduler.h
+++ b/src/host/trxcon/scheduler.h
@@ -24,6 +24,8 @@ struct trx_sched {
 	struct timeval clock;
 	/*! \brief Count of processed frames */
 	uint32_t fn_counter_proc;
+	/*! \brief Local frame counter advance */
+	uint32_t fn_counter_advance;
 	/*! \brief Frame counter */
 	uint32_t fn_counter_lost;
 	/*! \brief Frame callback timer */
diff --git a/src/host/trxcon/trxcon.c b/src/host/trxcon/trxcon.c
index 4a571b9a..07ab1698 100644
--- a/src/host/trxcon/trxcon.c
+++ b/src/host/trxcon/trxcon.c
@@ -69,6 +69,7 @@ static struct {
 	struct trx_instance *trx;
 	const char *trx_ip;
 	uint16_t trx_base_port;
+	uint32_t trx_fn_advance;
 } app_data;
 
 void *tall_trx_ctx = NULL;
@@ -143,6 +144,7 @@ static void print_help(void)
 	printf("  -d --debug        Change debug flags. Default: %s\n", DEBUG_DEFAULT);
 	printf("  -i --trx-ip       IP address of host runing TRX (default 127.0.0.1)\n");
 	printf("  -p --trx-port     Base port of TRX instance (default 5700)\n");
+	printf("  -f --trx-advance  Scheduler clock advance (default 20)\n");
 	printf("  -s --socket       Listening socket for layer23 (default /tmp/osmocom_l2)\n");
 	printf("  -D --daemonize    Run as daemon\n");
 }
@@ -157,11 +159,12 @@ static void handle_options(int argc, char **argv)
 			{"socket", 1, 0, 's'},
 			{"trx-ip", 1, 0, 'i'},
 			{"trx-port", 1, 0, 'p'},
+			{"trx-advance", 1, 0, 'f'},
 			{"daemonize", 0, 0, 'D'},
 			{0, 0, 0, 0}
 		};
 
-		c = getopt_long(argc, argv, "d:i:p:s:Dh",
+		c = getopt_long(argc, argv, "d:i:p:f:s:Dh",
 				long_options, &option_index);
 		if (c == -1)
 			break;
@@ -181,6 +184,9 @@ static void handle_options(int argc, char **argv)
 		case 'p':
 			app_data.trx_base_port = atoi(optarg);
 			break;
+		case 'f':
+			app_data.trx_fn_advance = atoi(optarg);
+			break;
 		case 's':
 			app_data.bind_socket = optarg;
 			break;
@@ -198,6 +204,7 @@ static void init_defaults(void)
 	app_data.bind_socket = "/tmp/osmocom_l2";
 	app_data.trx_ip = "127.0.0.1";
 	app_data.trx_base_port = 5700;
+	app_data.trx_fn_advance = 20;
 
 	app_data.debug_mask = NULL;
 	app_data.daemonize = 0;
@@ -263,7 +270,7 @@ int main(int argc, char **argv)
 	app_data.trx->l1l = app_data.l1l;
 
 	/* Init scheduler */
-	rc = sched_trx_init(app_data.trx);
+	rc = sched_trx_init(app_data.trx, app_data.trx_fn_advance);
 	if (rc)
 		goto exit;