Simplify PRACH beam handling, remove race

Simplify by removing a small malloc and memcpy() the beams. This should
also remove the data race between ru and gNB/CU-DU

executables/nr-ru.c

@@ -1222,7 +1222,7 @@ void *ru_thread(void *param)
 
           for (int prach_oc = 0; prach_oc < p->lower.num_prach_ocas; prach_oc++) {
             int prachStartSymbol = p->lower.prachStartSymbol + prach_oc * N_dur;
-            int beam_id = p->lower.beam ? p->lower.beam[prach_oc] : 0;
+            int beam_id = p->beams[prach_oc];
             //comment FK: the standard 38.211 section 5.3.2 has one extra term +14*N_RA_slot. This is because there prachStartSymbol is given wrt to start of the 15kHz slot or 60kHz slot. Here we work slot based, so this function is anyway only called in slots where there is PRACH. Its up to the MAC to schedule another PRACH PDU in the case there are there N_RA_slot \in {0,1}.
             rx_nr_prach_ru(ru,
                            p->lower.fmt, // could also use format

openair1/PHY/NR_TRANSPORT/nr_prach.c

@@ -46,8 +46,6 @@ void init_prach_list(prach_list_t *l, prach_type_t t)
 void free_nr_prach_entry(prach_list_t *l, prach_item_t *p)
 {
   pthread_mutex_lock(&l->prach_list_mutex);
-  if (p->type == prach_upper)
-    free_and_zero(p->upper.beam_nb);
   *p = (prach_item_t){.frame = -1, .slot = -1, .num_slots = -1};
   pthread_mutex_unlock(&l->prach_list_mutex);
 }
@@ -91,25 +89,27 @@ prach_item_t *nr_fill_prach(PHY_VARS_gNB *gNB, int SFN, int Slot, nfapi_nr_prach
   prach->num_slots = (format < 4) ? get_long_prach_dur(format, gNB->frame_parms.numerology_index) : 1;
   if (gNB->common_vars.beam_id) {
     int n_symb = get_nr_prach_duration(prach_pdu->prach_format);
-    prach->upper.beam_nb = calloc(prach_pdu->beamforming.dig_bf_interface, sizeof(*prach->upper.beam_nb));
+    AssertFatal(prach_pdu->beamforming.dig_bf_interface < NFAPI_MAX_NUM_BG_IF,
+                "impossible beams size %d\n",
+                prach_pdu->beamforming.dig_bf_interface);
     for (int i = 0; i < prach_pdu->beamforming.dig_bf_interface; i++) {
       int fapi_beam_idx = prach_pdu->beamforming.prgs_list[0].dig_bf_interface_list[i].beam_idx;
       int start_symb = prach_pdu->prach_start_symbol + i * n_symb;
       int bitmap = SL_to_bitmap(start_symb, n_symb);
-      prach->upper.beam_nb[i] = beam_index_allocation(gNB->enable_analog_das,
-                                                      fapi_beam_idx,
-                                                      &gNB->gNB_config.analog_beamforming_ve,
-                                                      &gNB->common_vars,
-                                                      Slot,
-                                                      NR_NUMBER_OF_SYMBOLS_PER_SLOT,
-                                                      bitmap);
+      prach->beams[i] = beam_index_allocation(gNB->enable_analog_das,
+                                              fapi_beam_idx,
+                                              &gNB->gNB_config.analog_beamforming_ve,
+                                              &gNB->common_vars,
+                                              Slot,
+                                              NR_NUMBER_OF_SYMBOLS_PER_SLOT,
+                                              bitmap);
     }
   }
   prach->pdu = *prach_pdu;
   return prach;
 }
 
-void nr_fill_prach_ru(RU_t *ru, int SFN, int Slot, nfapi_nr_prach_pdu_t *prach_pdu, int *beam_id)
+void nr_fill_prach_ru(RU_t *ru, int SFN, int Slot, nfapi_nr_prach_pdu_t *prach_pdu, int *beams)
 {
   prach_item_t *prach = find_nr_prach(&ru->prach_list, SFN, Slot, SEARCH_EXIST_OR_FREE);
   if (!prach) {
@@ -123,9 +123,9 @@ void nr_fill_prach_ru(RU_t *ru, int SFN, int Slot, nfapi_nr_prach_pdu_t *prach_p
                           .num_slots = (fmt < 4) ? get_long_prach_dur(fmt, ru->nr_frame_parms->numerology_index) : 1,
                           .lower = {.fmt = fmt,
                                     .numRA = prach_pdu->num_ra,
-                                    .beam = beam_id,
                                     .prachStartSymbol = prach_pdu->prach_start_symbol,
                                     .num_prach_ocas = prach_pdu->num_prach_ocas}};
+  memcpy(prach->beams, beams, sizeof(prach->beams));
 }
 
 void rx_nr_prach_ru(RU_t *ru,

openair1/PHY/defs_common.h

@@ -1006,11 +1006,11 @@ typedef struct {
   int frame;
   int slot;
   int num_slots; // prach duration in slots
+  int beams[NFAPI_MAX_NUM_BG_IF];
   prach_type_t type;
   union {
     struct {
       // identifier for concurrent beams
-      int *beam_nb;
       nfapi_nr_prach_pdu_t pdu;
     } upper;
     struct {
@@ -1018,7 +1018,6 @@ typedef struct {
       int numRA;
       int prachStartSymbol;
       int num_prach_ocas;
-      int *beam;
     } lower;
   };
   nfapi_nr_prach_pdu_t pdu;

openair1/SCHED_NR/fapi_nr_l1.c

@@ -156,7 +156,7 @@ void nr_schedule_ul_tti_req(PHY_VARS_gNB *gNB, nfapi_nr_ul_tti_request_t *UL_tti
         nfapi_nr_prach_pdu_t *prach_pdu = &UL_tti_req->pdus_list[i].prach_pdu;
         prach_item_t *prach = nr_fill_prach(gNB, UL_tti_req->SFN, UL_tti_req->Slot, prach_pdu);
         if (prach && (gNB->RU_list[0]->if_south == LOCAL_RF || gNB->RU_list[0]->if_south == REMOTE_IF5))
-          nr_fill_prach_ru(gNB->RU_list[0], UL_tti_req->SFN, UL_tti_req->Slot, prach_pdu, prach->upper.beam_nb);
+          nr_fill_prach_ru(gNB->RU_list[0], UL_tti_req->SFN, UL_tti_req->Slot, prach_pdu, prach->beams);
         break;
       case NFAPI_NR_UL_CONFIG_SRS_PDU_TYPE:
         LOG_D(NR_PHY,