From f80b09ac990abe0593b92c0e288273a8bb1e5bc9 Mon Sep 17 00:00:00 2001
From: Guido Casati <hello@guidocasati.com>
Date: Mon, 28 Oct 2024 08:13:00 +0100
Subject: [PATCH] Simplified use of nb_nr_inst

* nb_nr_inst represents the number of gNB instances and the number of RAN contexts
* it used also to count the number of RRC instances in the node
* it is set from config file in NRRCConfig, therefore redundant checks after
  this function have been removed
* redundant global variable NB_gNB_INST, set after nb_nr_inst, was removed
---
 executables/nr-gnb.c          |  3 ---
 executables/nr-softmodem.c    | 18 +++++-------------
 openair2/GNB_APP/gnb_app.c    |  2 --
 openair2/GNB_APP/gnb_config.c |  6 +++++-
 4 files changed, 10 insertions(+), 19 deletions(-)

diff --git a/executables/nr-gnb.c b/executables/nr-gnb.c
index f250893133..6e9dd91a59 100644
--- a/executables/nr-gnb.c
+++ b/executables/nr-gnb.c
@@ -400,10 +400,7 @@ void term_gNB_Tpool(int inst) {
 void init_eNB_afterRU(void) {
   int inst,ru_id,i,aa;
   PHY_VARS_gNB *gNB;
-  LOG_D(PHY, "%s() RC.nb_nr_inst:%d\n", __FUNCTION__, RC.nb_nr_inst);
 
-  if(NFAPI_MODE == NFAPI_MODE_PNF)
-    RC.nb_nr_inst = 1;
   for (inst=0; inst<RC.nb_nr_inst; inst++) {
     LOG_D(PHY, "RC.nb_nr_CC[inst:%d]:%p\n", inst, RC.gNB[inst]);
 
diff --git a/executables/nr-softmodem.c b/executables/nr-softmodem.c
index 0ac8f64827..16e34050da 100644
--- a/executables/nr-softmodem.c
+++ b/executables/nr-softmodem.c
@@ -103,7 +103,6 @@ unsigned int mmapped_dma=0;
 
 uint64_t downlink_frequency[MAX_NUM_CCs][4];
 int32_t uplink_frequency_offset[MAX_NUM_CCs][4];
-unsigned char NB_gNB_INST = 1;
 char *uecap_file;
 
 runmode_t mode = normal_txrx;
@@ -255,18 +254,12 @@ static int create_gNB_tasks(ngran_node_t node_type, configmodule_interface_t *cf
                "Number of gNB is greater than gNB defined in configuration file (%d/%d)!",
                gnb_nb, RC.nb_nr_inst);
 
-  LOG_D(GNB_APP, "Allocating gNB_RRC_INST for %d instances\n", RC.nb_nr_inst);
+  LOG_D(GNB_APP, "Allocating gNB_RRC_INST\n");
+  RC.nrrrc = calloc(1, sizeof(*RC.nrrrc));
+  RC.nrrrc[0] = calloc(1, sizeof(gNB_RRC_INST));
+  RCconfig_NRRRC(RC.nrrrc[0]);
 
-  if (RC.nb_nr_inst > 0) {
-    AssertFatal(RC.nb_nr_inst == 1, "multiple RRC instances are not supported\n");
-    RC.nrrrc = calloc(1, sizeof(*RC.nrrrc));
-    RC.nrrrc[0] = calloc(1,sizeof(gNB_RRC_INST));
-    RCconfig_NRRRC(RC.nrrrc[0]);
-  }
-
-  if (RC.nb_nr_inst > 0 &&
-      !get_softmodem_params()->nsa &&
-      !(node_type == ngran_gNB_DU))  {
+  if (!get_softmodem_params()->nsa && !(node_type == ngran_gNB_DU)) {
     // we start pdcp in both cuup (for drb) and cucp (for srb)
     init_pdcp();
   }
@@ -373,7 +366,6 @@ static void get_options(configmodule_interface_t *cfg)
     memset((void *)&RC,0,sizeof(RC));
     /* Read RC configuration file */
     NRRCConfig();
-    NB_gNB_INST = RC.nb_nr_inst;
     NB_RU   = RC.nb_RU;
   }
 }
diff --git a/openair2/GNB_APP/gnb_app.c b/openair2/GNB_APP/gnb_app.c
index 49b53aa572..e62ddf38b0 100644
--- a/openair2/GNB_APP/gnb_app.c
+++ b/openair2/GNB_APP/gnb_app.c
@@ -54,8 +54,6 @@
 #include "gnb_config.h"
 #include "openair2/LAYER2/NR_MAC_gNB/mac_proto.h"
 
-extern unsigned char NB_gNB_INST;
-
 extern RAN_CONTEXT_t RC;
 
 #define GNB_REGISTER_RETRY_DELAY 10
diff --git a/openair2/GNB_APP/gnb_config.c b/openair2/GNB_APP/gnb_config.c
index 8273141f8a..1f600331d7 100644
--- a/openair2/GNB_APP/gnb_config.c
+++ b/openair2/GNB_APP/gnb_config.c
@@ -2136,6 +2136,11 @@ void NRRCConfig(void) {
 
   config_get(config_get_if(), GNBSParams, sizeofArray(GNBSParams), NULL);
   RC.nb_nr_inst = GNBSParams[GNB_ACTIVE_GNBS_IDX].numelt;
+  AssertFatal(RC.nb_nr_inst == NUMBER_OF_gNB_MAX,
+              "Configuration error: RC.nb_nr_inst (%d) must equal NUMBER_OF_gNB_MAX (%d).\n"
+              "Currently, only one instance of each layer (L1, L2, L3) is supported.\n"
+              "Ensure that nb_nr_inst matches the maximum allowed gNB instances in this configuration.",
+              RC.nb_nr_inst, NUMBER_OF_gNB_MAX);
 
   // Get num MACRLC instances
   config_getlist(config_get_if(), &MACRLCParamList, NULL, 0, NULL);
@@ -2383,7 +2388,6 @@ int gNB_app_handle_f1ap_gnb_cu_configuration_update(f1ap_gnb_cu_configuration_up
         gnb_cu_cfg_update->num_cells_to_activate, RC.nb_nr_inst);
 
   AssertFatal(gnb_cu_cfg_update->num_cells_to_activate == 1, "only one cell supported at the moment\n");
-  AssertFatal(RC.nb_nr_inst == 1, "expected one instance\n");
   gNB_MAC_INST *mac = RC.nrmac[0];
   NR_SCHED_LOCK(&mac->sched_lock);
   for (j = 0; j < gnb_cu_cfg_update->num_cells_to_activate; j++) {