fix(FHI 7.2): PRACH frame test

A test was missing in the PRACH RX function of the FHI 7.2 in order to
know if the frame had a PRACH occasion.
This was leading to continuous warning messages as PRACH RX was
triggered on frames in which PRACH was not expected by the scheduler.

radio/fhi_72/oaioran.c

@@ -172,14 +172,16 @@ static int read_prach_data(ru_info_t *ru, int frame, int slot)
 
   struct xran_fh_init *fh_init = get_xran_fh_init();
   struct xran_fh_config *fh_cfg = get_xran_fh_config(0);
-  int prach_sym = get_prach_conf_duration(0);
+  nr_prach_info_t prach_info = get_prach_info(0);
   struct xran_ru_config *ru_conf = &fh_cfg->ru_conf;
   int slots_per_frame = 10 << fh_cfg->frame_conf.nNumerology;
   int slots_per_subframe = 1 << fh_cfg->frame_conf.nNumerology;
 
   int tti = slots_per_frame * (frame) + (slot);
   uint32_t subframe = slot / slots_per_subframe;
-  uint32_t is_prach_slot = xran_is_prach_slot(0, subframe, (slot % slots_per_subframe));
+  // PRACH occasion in a frame if and only if SFN % x == y, TS 38.211 Table 6.3.3.2-2/3/4
+  uint32_t is_prach_frame = (frame % prach_info.x == prach_info.y);
+  uint32_t is_prach_slot = is_prach_frame && xran_is_prach_slot(0, subframe, (slot % slots_per_subframe));
 
   int nb_rx_per_ru = ru->nb_rx / fh_init->xran_ports;
   /* If it is PRACH slot, copy prach IQ from XRAN PRACH buffer to OAI PRACH buffer */
@@ -188,7 +190,7 @@ static int read_prach_data(ru_info_t *ru, int frame, int slot)
       LOG_W(HW, "we get rach data from ru, but it is not scheduled %d.%d\n", frame, slot);
       return -1;
     }
-    for (sym_idx = 0; sym_idx < prach_sym; sym_idx++) {
+    for (sym_idx = 0; sym_idx < prach_info.N_dur; sym_idx++) {
       for (int aa = 0; aa < ru->nb_rx; aa++) {
         int16_t *dst, *src;
         int idx = 0;

radio/fhi_72/oran-init.c

@@ -30,9 +30,7 @@
 
 #include "common/utils/assertions.h"
 #include "common/utils/LOG/log.h"
-#include "common/utils/nr/nr_common.h"
 #include "common_lib.h"
-#include "openair2/LAYER2/NR_MAC_COMMON/nr_prach_config.h"
 
 /* PRACH data samples are 32 bits wide (16bits for I/Q). Each packet contains
  * 840 samples for long sequence or 144 for short sequence. The payload length
@@ -50,7 +48,7 @@ void *gxran_handle;
 
 static struct xran_fh_init g_fh_init = {0};
 static struct xran_fh_config g_fh_config[XRAN_PORTS_NUM] = {0};
-static uint32_t g_prach_conf_duration[XRAN_PORTS_NUM] = {0};
+static nr_prach_info_t g_prach_info[XRAN_PORTS_NUM] = {0};
 
 static uint32_t get_nSW_ToFpga_FTH_TxBufferLen(int mu, int sections)
 {
@@ -470,11 +468,9 @@ int *oai_oran_initialize(struct xran_fh_init *xran_fh_init, struct xran_fh_confi
     // retrieve and store prach duration
     uint8_t idx = xran_fh_config[o_xu_id].prach_conf.nPrachConfIdx;
     const struct xran_frame_config *fc = &xran_fh_config[o_xu_id].frame_conf;
-    g_prach_conf_duration[o_xu_id] =
-        get_nr_prach_occasion_info_from_index(idx,
-                                              fc->nNumerology > 2 ? FR2 : FR1,
-                                              fc->nFrameDuplexType == XRAN_FDD ? duplex_mode_FDD : duplex_mode_TDD)
-            .N_dur;
+    g_prach_info[o_xu_id] = get_nr_prach_occasion_info_from_index(idx,
+                                                                  fc->nNumerology > 2 ? FR2 : FR1,
+                                                                  fc->nFrameDuplexType == XRAN_FDD ? duplex_mode_FDD : duplex_mode_TDD);
   }
 
   // store config after xran initialization -- xran makes modifications to
@@ -504,9 +500,9 @@ struct xran_fh_config *get_xran_fh_config(uint32_t port_id)
   return &g_fh_config[port_id];
 }
 
-uint32_t get_prach_conf_duration(uint32_t port_id)
+nr_prach_info_t get_prach_info(uint32_t port_id)
 {
   struct xran_fh_init *fh_init = get_xran_fh_init();
   DevAssert(port_id < fh_init->xran_ports);
-  return g_prach_conf_duration[port_id];
+  return g_prach_info[port_id];
 }

radio/fhi_72/oran-init.h

@@ -22,6 +22,9 @@
 #ifndef ORAN_INIT_H
 #define ORAN_INIT_H
 
+#include "common/utils/nr/nr_common.h"
+#include "openair2/LAYER2/NR_MAC_COMMON/nr_prach_config.h"
+
 typedef struct oran_bufs {
   struct xran_flat_buffer tx[XRAN_MAX_ANTENNA_NR][XRAN_N_FE_BUF_LEN][XRAN_NUM_OF_SYMBOL_PER_SLOT];
   struct xran_flat_buffer tx_prbmap[XRAN_MAX_ANTENNA_NR][XRAN_N_FE_BUF_LEN];
@@ -62,6 +65,16 @@ int *oai_oran_initialize(struct xran_fh_init *fh_init, struct xran_fh_config *fh
 oran_buf_list_t *get_xran_buffers(uint32_t port_id);
 struct xran_fh_init *get_xran_fh_init(void);
 struct xran_fh_config *get_xran_fh_config(uint32_t port_id);
-uint32_t get_prach_conf_duration(uint32_t port_id);
+
+/**
+ * @brief queries PRACH information necessary for the FHI
+ *
+ * @arg port_id XRAN port id
+ * @return PRACH information holding among other information:
+ * - N_dur PRACH duration from TS 38.211 Table 6.3.3.2-2/3/4
+ * - x from TS 38.211 Table 6.3.3.2-2/3/4
+ * - y from TS 38.211 Table 6.3.3.2-2/3/4
+ */
+nr_prach_info_t get_prach_info(uint32_t port_id);
 
 #endif /* ORAN_INIT_H */