FHI72: cleanup: remove first_read_set

first_read_set seems to have the function of making frame/slot time
advance only if we started to read the samples in
xran_fh_rx_read_slot(). I interpret that as "only advance the time if
the gNB is reading from xran", which does not make sense to me, because
xran advances the time anyway. Also, polling would not notice, and
no-polling would simply warn about double messages. So the outcome is
likely the same, whether first_read_set is set or not.

I checked in multiple CI runs; it happens that first_read_set is always
set already when oai_xran_fh_rx_callback() is called anyway.

radio/fhi_72/oaioran.c

@@ -46,7 +46,6 @@
 // Declare variable useful for the send buffer function
 volatile uint8_t first_call_set = 0;
 volatile uint8_t first_rx_set = 0;
-volatile int first_read_set = 0;
 
 int xran_is_prach_slot(uint8_t PortId, uint32_t subframe_id, uint32_t slot_id);
 #include "common/utils/LOG/log.h"
@@ -116,42 +115,40 @@ void oai_xran_fh_rx_callback(void *pCallbackTag, xran_status_t status)
 #endif
     if (first_call_set) {
       if (!first_rx_set) {
-        LOG_I(NR_PHY, "first_rx is set (num_ports %d), first_read_set %d\n", num_ports, first_read_set);
+        LOG_I(NR_PHY, "first_rx is set (num_ports %d)\n", num_ports);
       }
       first_rx_set = 1;
-      if (first_read_set == 1) {
-        slot2 = slot + (subframe * slots_per_subframe);
-        rx_RU[ru_id][slot2] = 1;
-        if (last_frame > 0 && frame > 0
-            && ((slot2 > 0 && last_frame != frame) || (slot2 == 0 && last_frame != ((1024 + frame - 1) & 1023))))
-          LOG_E(PHY, "Jump in frame counter last_frame %d => %d, slot %d\n", last_frame, frame, slot2);
-        for (int i = 0; i < num_ports; i++) {
-          if (rx_RU[i][slot2] == 0)
-            return;
-        }
-        for (int i = 0; i < num_ports; i++)
-          rx_RU[i][slot2] = 0;
+      slot2 = slot + (subframe * slots_per_subframe);
+      rx_RU[ru_id][slot2] = 1;
+      if (last_frame > 0 && frame > 0
+          && ((slot2 > 0 && last_frame != frame) || (slot2 == 0 && last_frame != ((1024 + frame - 1) & 1023))))
+        LOG_E(PHY, "Jump in frame counter last_frame %d => %d, slot %d\n", last_frame, frame, slot2);
+      for (int i = 0; i < num_ports; i++) {
+        if (rx_RU[i][slot2] == 0)
+          return;
+      }
+      for (int i = 0; i < num_ports; i++)
+        rx_RU[i][slot2] = 0;
 
-        if (last_slot == -1 || slot2 != last_slot) {
+      if (last_slot == -1 || slot2 != last_slot) {
 #ifndef USE_POLLING
-          notifiedFIFO_elt_t *req = newNotifiedFIFO_elt(sizeof(oran_sync_info_t), 0, &oran_sync_fifo, NULL);
-          oran_sync_info_t *info = NotifiedFifoData(req);
-          info->tti = tti;
-          info->sl = slot2;
-          info->f = frame;
-          LOG_D(PHY, "Push %d.%d.%d (slot %d, subframe %d,last_slot %d)\n", frame, info->sl, slot, ru_id, subframe, last_slot);
-          pushNotifiedFIFO(&oran_sync_fifo, req);
+        notifiedFIFO_elt_t *req = newNotifiedFIFO_elt(sizeof(oran_sync_info_t), 0, &oran_sync_fifo, NULL);
+        oran_sync_info_t *info = NotifiedFifoData(req);
+        info->tti = tti;
+        info->sl = slot2;
+        info->f = frame;
+        LOG_D(PHY, "Push %d.%d.%d (slot %d, subframe %d,last_slot %d)\n", frame, info->sl, slot, ru_id, subframe, last_slot);
+        pushNotifiedFIFO(&oran_sync_fifo, req);
 #else
-          LOG_D(PHY, "Writing %d.%d.%d (slot %d, subframe %d,last_slot %d)\n", frame, slot2, ru_id, slot, subframe, last_slot);
-          oran_sync_info.tti = tti;
-          oran_sync_info.sl = slot2;
-          oran_sync_info.f = frame;
+        LOG_D(PHY, "Writing %d.%d.%d (slot %d, subframe %d,last_slot %d)\n", frame, slot2, ru_id, slot, subframe, last_slot);
+        oran_sync_info.tti = tti;
+        oran_sync_info.sl = slot2;
+        oran_sync_info.f = frame;
 #endif
-        } else
-          LOG_E(PHY, "Cannot Push %d.%d.%d (slot %d, subframe %d,last_slot %d)\n", frame, slot2, ru_id, slot, subframe, last_slot);
-        last_slot = slot2;
-        last_frame = frame;
-      } // first_read_set == 1
+      } else
+        LOG_E(PHY, "Cannot Push %d.%d.%d (slot %d, subframe %d,last_slot %d)\n", frame, slot2, ru_id, slot, subframe, last_slot);
+      last_slot = slot2;
+      last_frame = frame;
     } // first_call_set
   } // rx_sym == 7
 }
@@ -274,7 +271,6 @@ int xran_fh_rx_read_slot(ru_info_t *ru, int *frame, int *slot)
   void *ptr = NULL;
   int32_t *pos = NULL;
   int idx = 0;
-  first_read_set = 1;
 
   static int64_t old_rx_counter[XRAN_PORTS_NUM] = {0};
   static int64_t old_tx_counter[XRAN_PORTS_NUM] = {0};