introduce concept of superchannel to data structures

We treat the superchannel as an extra, separate timeslot.  Initially
I thought of simply re-using TS1, but keeping the superchannel
separate ensures that it doesn't inherit any state (like half-sent
HDLC frames) from another timeslot when we switch between the modes
at runtime.

Change-Id: I0aacf251e155de2bb6ad03ffc4181067b22f1c90

4 files changed, 33 insertions, 6 deletions

diff --git a/include/osmocom/e1d/proto.h b/include/osmocom/e1d/proto.h
index 56064b8..6711332 100644
--- a/include/osmocom/e1d/proto.h
+++ b/include/osmocom/e1d/proto.h
@@ -71,6 +71,7 @@ enum osmo_e1dp_ts_mode {
 
 #define E1DP_MAGIC	0x00e1
 #define E1DP_MAX_LEN	4096
+#define E1DP_TS_SUPERCHAN 0xfe
 #define E1DP_INVALID	0xff
 #define E1DP_DEFAULT_SOCKET "/tmp/osmo-e1d.ctl"
 
diff --git a/src/ctl.c b/src/ctl.c
index 482366f..5322ab4 100644
--- a/src/ctl.c
+++ b/src/ctl.c
@@ -68,7 +68,12 @@ e1_intf_find_line(struct e1_intf *intf, uint8_t id)
 static struct e1_ts *
 _e1d_get_ts(struct e1_line *line, uint8_t ts)
 {
-	return (ts < 32) ? &line->ts[ts] : NULL;
+	if (ts < 32)
+		return &line->ts[ts];
+	else if (ts == E1DP_TS_SUPERCHAN)
+		return &line->superchan;
+	else
+		return NULL;
 }
 
 static void
diff --git a/src/e1d.h b/src/e1d.h
index f556e8f..2b8e32b 100644
--- a/src/e1d.h
+++ b/src/e1d.h
@@ -55,15 +55,28 @@ struct e1_ts {
 	int fd;
 };
 
+enum e1_line_mode {
+	/* 31 individual 64k timeslots, as used on 3GPP Abis, 3GPP A or ISDN */
+	E1_LINE_MODE_CHANNELIZED,
+	/* 1 channel group spanning all 31 TS, as used e.g. when using Frame Relay
+	 * or raw HDLC over channelized E1. */
+	E1_LINE_MODE_SUPERCHANNEL,
+};
+
 struct e1_line {
 	struct llist_head list;
 
 	struct e1_intf *intf;
 	uint8_t id;
 
+	enum e1_line_mode mode;
+
 	void *drv_data;
 
+	/* timeslots for channelized mode */
 	struct e1_ts ts[32];
+	/* superchannel */
+	struct e1_ts superchan;
 };
 
 enum e1_driver {
diff --git a/src/intf_line.c b/src/intf_line.c
index e206f76..421c528 100644
--- a/src/intf_line.c
+++ b/src/intf_line.c
@@ -33,6 +33,7 @@
 
 #include <osmocom/core/isdnhdlc.h>
 #include <osmocom/core/utils.h>
+#include <osmocom/e1d/proto.h>
 
 #include "e1d.h"
 #include "log.h"
@@ -90,6 +91,14 @@ e1_intf_destroy(struct e1_intf *intf)
 	talloc_free(intf);
 }
 
+static void
+_ts_init(struct e1_ts *ts, struct e1_line *line, int id)
+{
+	ts->line = line;
+	ts->id = id;
+	ts->fd = -1;
+}
+
 struct e1_line *
 e1_line_new(struct e1_intf *intf, void *drv_data)
 {
@@ -100,12 +109,11 @@ e1_line_new(struct e1_intf *intf, void *drv_data)
 
 	line->intf = intf;
 	line->drv_data = drv_data;
+	line->mode = E1_LINE_MODE_CHANNELIZED;
 
-	for (int i=0; i<32; i++) {
-		line->ts[i].line = line;
-		line->ts[i].id = i;
-		line->ts[i].fd = -1;
-	}
+	for (int i=0; i<32; i++)
+		_ts_init(&line->ts[i], line, i);
+	_ts_init(&line->superchan, line, E1DP_TS_SUPERCHAN);
 
 	INIT_LLIST_HEAD(&line->list);