From 86f4c093d1ead974ab0b8d67eaa5ca8946379616 Mon Sep 17 00:00:00 2001
From: Pau Espin Pedrol <pespin@sysmocom.de>
Date: Tue, 8 Jun 2021 18:53:40 +0200
Subject: [PATCH] pcuif: Support receiving System Information 2

OsmoPCU will need this SI2 in order to gain knowledge of the BCCH
Frequency List being broadcasted, in order to build a per-MS specific
Neighbour List using NC_FREQUENCY_LIST bits in Packet Measurement Order.

Related: SYS#5303
Change-Id: I4a9c4f70beac6805322a19835a0d30f7247780b4
---
 src/bts.h         |  3 +++
 src/pcu_l1_if.cpp | 30 ++++++++++++++++++++++++++++++
 2 files changed, 33 insertions(+)

diff --git a/src/bts.h b/src/bts.h
index 2a7d8837..a2f4598e 100644
--- a/src/bts.h
+++ b/src/bts.h
@@ -231,6 +231,9 @@ struct gprs_rlcmac_bts {
 
 	uint8_t si1[GSM_MACBLOCK_LEN];
 	bool si1_is_set;
+	uint8_t si2[GSM_MACBLOCK_LEN];
+	bool si2_is_set;
+	struct gsm_sysinfo_freq si2_bcch_cell_list[1024];
 	uint8_t si3[GSM_MACBLOCK_LEN];
 	bool si3_is_set;
 	uint8_t si13[GSM_MACBLOCK_LEN];
diff --git a/src/pcu_l1_if.cpp b/src/pcu_l1_if.cpp
index 0453b92c..818cb1aa 100644
--- a/src/pcu_l1_if.cpp
+++ b/src/pcu_l1_if.cpp
@@ -286,9 +286,28 @@ int pcu_rx_data_ind_pdtch(struct gprs_rlcmac_bts *bts, struct gprs_rlcmac_pdch *
 	return rc;
 }
 
+static int list_arfcn(const struct gprs_rlcmac_bts *bts, const struct gsm_sysinfo_freq *freq, const char *text)
+{
+	int n = 0, i;
+	for (i = 0; i < 1024; i++) {
+		if (freq[i].mask) {
+			if (!n)
+				LOGP(DL1IF, LOGL_INFO, "BTS%d: %s", bts->nr, text);
+			LOGPC(DL1IF, LOGL_INFO, " %d", i);
+			n++;
+		}
+	}
+	if (n)
+		LOGPC(DL1IF, LOGL_INFO, "\n");
+
+	return n;
+}
+
 static int pcu_rx_data_ind_bcch(struct gprs_rlcmac_bts *bts, uint8_t *data, uint8_t len)
 {
+	struct gsm48_system_information_type_2 *si2;
 	const uint8_t *si_ro;
+
 	switch (len) {
 	case 0:
 		/* Due to historical reasons also accept a completely empty message as
@@ -305,6 +324,9 @@ static int pcu_rx_data_ind_bcch(struct gprs_rlcmac_bts *bts, uint8_t *data, uint
 		case SYSINFO_TYPE_1:
 			bts->si1_is_set = false;
 			break;
+		case SYSINFO_TYPE_2:
+			bts->si2_is_set = false;
+			break;
 		case SYSINFO_TYPE_3:
 			bts->si3_is_set = false;
 			break;
@@ -328,6 +350,14 @@ static int pcu_rx_data_ind_bcch(struct gprs_rlcmac_bts *bts, uint8_t *data, uint
 			memcpy(bts->si1, data, GSM_MACBLOCK_LEN);
 			bts->si1_is_set = true;
 			break;
+		case GSM48_MT_RR_SYSINFO_2:
+			memcpy(bts->si2, data, GSM_MACBLOCK_LEN);
+			bts->si2_is_set = true;
+			si2 = (struct gsm48_system_information_type_2 *)bts->si2;
+			gsm48_decode_freq_list(bts->si2_bcch_cell_list, si2->bcch_frequency_list,
+					       sizeof(si2->bcch_frequency_list), 0xce, 1);
+			list_arfcn(bts, bts->si2_bcch_cell_list, "SI2 Neighbour cells in same band:");
+			break;
 		case GSM48_MT_RR_SYSINFO_3:
 			memcpy(bts->si3, data, GSM_MACBLOCK_LEN);
 			bts->si3_is_set = true;