sysinfo: Make our SI scheduling more complete

We now implement the fairly complex rules for schedulign of
SI 2bis/2ter/2quater, 13 and 9 on TC=4 and TC=5 of the BCCH Norm.

The patch is currently untested.

1 files changed, 80 insertions, 5 deletions

diff --git a/src/common/sysinfo.c b/src/common/sysinfo.c
index 66907761..874fb6d9 100644
--- a/src/common/sysinfo.c
+++ b/src/common/sysinfo.c
@@ -24,24 +24,99 @@
 
 #include <osmo-bts/gsm_data.h>
 
+#define BTS_HAS_SI(bts, sinum)	((bts)->si_valid & (1 << sinum))
+
+/* Apply the rules from 05.02 6.3.1.3 Mapping of BCCH Data */
 uint8_t *bts_sysinfo_get(struct gsm_bts *bts, struct gsm_time *g_time)
 {
-	/* Apply the rules from 05.02 6.3.1.3 Mapping of BCCH Data */
+	struct gsm_bts_role_bts *btsb = bts_role_bts(bts);
+	unsigned int tc4_cnt = 0;
+	unsigned int tc4_sub[4];
+
+	/* System information type 2 bis or 2 ter messages are sent if
+	 * needed, as determined by the system operator.  If only one of
+	 * them is needed, it is sent when TC = 5.  If both are needed,
+	 * 2bis is sent when TC = 5 and 2ter is sent at least once
+	 * within any of 4 consecutive occurrences of TC = 4.  */
+	/* System information type 2 quater is sent if needed, as
+	 * determined by the system operator. If sent on BCCH Norm, it
+	 * shall be sent when TC = 5 if neither of 2bis and 2ter are
+	 * used, otherwise it shall be sent at least once within any of
+	 * 4 consecutive occurrences of TC = 4. If sent on BCCH Ext, it
+	 * is sent at least once within any of 4 consecutive occurrences
+	 * of TC = 5. */
+	/* System Information type 9 is sent in those blocks with
+	 * TC = 4 which are specified in system information type 3 as
+	 * defined in 3GPP TS 04.08.  */
+	/* System Information Type 13 need only be sent if GPRS support
+	 * is indicated in one or more of System Information Type 3 or 4
+	 * or 7 or 8 messages. These messages also indicate if the
+	 * message is sent on the BCCH Norm or if the message is
+	 * transmitted on the BCCH Ext. In the case that the message is
+	 * sent on the BCCH Norm, it is sent at least once within any of
+	 * 4 consecutive occurrences of TC = 4. */
+
+	/* We only implement BCCH Norm at this time */
 	switch (g_time->tc) {
 	case 0:
+		/* System Information Type 1 need only be sent if
+		 * frequency hopping is in use or when the NCH is
+		 * present in a cell. If the MS finds another message
+		 * when TC = 0, it can assume that System Information
+		 * Type 1 is not in use.  */
 		return GSM_BTS_SI(bts, SYSINFO_TYPE_1);
 	case 1:
+		/* A SI 2 message will be sent at least every time TC = 1. */
 		return GSM_BTS_SI(bts, SYSINFO_TYPE_2);
 	case 2:
 		return GSM_BTS_SI(bts, SYSINFO_TYPE_3);
 	case 3:
 		return GSM_BTS_SI(bts, SYSINFO_TYPE_4);
 	case 4:
-		/* FIXME: iterate over 2ter, 2quater, 9, 13 */
-		return GSM_BTS_SI(bts, SYSINFO_TYPE_2ter);
+		/* iterate over 2ter, 2quater, 9, 13 */
+		/* determine how many SI we need to send on TC=4,
+		 * and which of them we send when */
+		if (BTS_HAS_SI(bts, SYSINFO_TYPE_2ter)) {
+			tc4_sub[tc4_cnt] = SYSINFO_TYPE_2ter;
+			tc4_cnt += 1; /* 2bis */
+		}
+		if (BTS_HAS_SI(bts, SYSINFO_TYPE_2quater) &&
+		    (BTS_HAS_SI(bts, SYSINFO_TYPE_2bis) ||
+		     BTS_HAS_SI(bts, SYSINFO_TYPE_2bis))) {
+			tc4_sub[tc4_cnt] = SYSINFO_TYPE_2quater;
+			tc4_cnt += 1;
+		}
+		if (BTS_HAS_SI(bts, SYSINFO_TYPE_13)) {
+			tc4_sub[tc4_cnt] = SYSINFO_TYPE_13;
+			tc4_cnt += 1;
+		}
+		if (BTS_HAS_SI(bts, SYSINFO_TYPE_9)) {
+			/* FIXME: check SI3 scheduling info! */
+			tc4_sub[tc4_cnt] = SYSINFO_TYPE_9;
+			tc4_cnt += 1;
+		}
+		/* increment static counter by one, modulo count */
+		btsb->si.tc4_ctr = (btsb->si.tc4_ctr + 1) % tc4_cnt;
+		return GSM_BTS_SI(bts, tc4_sub[btsb->si.tc4_ctr]);
 	case 5:
-		/* FIXME: 2bis, 2ter, 2quater */
-		return GSM_BTS_SI(bts, SYSINFO_TYPE_2bis);
+		/* 2bis, 2ter, 2quater */
+		if (BTS_HAS_SI(bts, SYSINFO_TYPE_2bis) &&
+		    !BTS_HAS_SI(bts, SYSINFO_TYPE_2ter))
+			return GSM_BTS_SI(bts, SYSINFO_TYPE_2bis);
+
+		else if (BTS_HAS_SI(bts, SYSINFO_TYPE_2ter) &&
+			 !BTS_HAS_SI(bts, SYSINFO_TYPE_2bis))
+			return GSM_BTS_SI(bts, SYSINFO_TYPE_2ter);
+
+		else if (BTS_HAS_SI(bts, SYSINFO_TYPE_2bis) &&
+			 BTS_HAS_SI(bts, SYSINFO_TYPE_2ter))
+			return GSM_BTS_SI(bts, SYSINFO_TYPE_2bis);
+
+		else if (BTS_HAS_SI(bts, SYSINFO_TYPE_2quater) &&
+			 !BTS_HAS_SI(bts, SYSINFO_TYPE_2bis) &&
+			 !BTS_HAS_SI(bts, SYSINFO_TYPE_2ter))
+			return GSM_BTS_SI(bts, SYSINFO_TYPE_2quater);
+		break;
 	case 6:
 		return GSM_BTS_SI(bts, SYSINFO_TYPE_3);
 	case 7: