Refactor UE (RRC/MAC): typed NR_MAC_RRC_START_RA for T300 and re-estab

RRC starts random access via NR_MAC_RRC_START_RA with an explicit
cause. RA trigger is no longer piggybacked on NR_MAC_RRC_CONFIG_RESET.
T300 expiry and RRC re-establishment are the call sites switched in this
commit. MAC handles setup/T300 and re-establishment paths in
nr_mac_start_ra().

Changes:
- Add nr_mac_rrc_types.h (nr_mac_ra_start_cause_t)
- Add nr_mac_rrc_start_ra_t in rrc_messages_types.h
- In rrc_UE.c, add nr_rrc_trigger_mac_ra(), call it from
  handle_t300_expiry and nr_rrc_initiate_rrcReestablishment
- In config_ue.c:
  - add nr_mac_start_ra() entry point with causes switch
  - add nr_rrc_mac_start_ra() handler
  - remove T300_EXPIRY, RE_ESTABLISHMENT reset handling
    in nr_rrc_mac_config_req_reset, now delegated to
    nr_mac_start_ra
- mac_defs.h: drop T300_EXPIRY from NR_UE_MAC_reset_cause_t

Signed-off-by: Guido Casati <guido.casati@openairinterface.org>

openair2/COMMON/rrc_messages_types.h

@@ -30,6 +30,7 @@
 #include "NR_BCCH-BCH-Message.h"
 #include "NR_ReestablishmentCause.h"
 #include "NR_UE-NR-Capability.h"
+#include "RRC/NR_UE/nr_mac_rrc_types.h"
 
 //-------------------------------------------------------------------------------------------//
 // Messages for RRC logging
@@ -460,6 +461,9 @@ typedef struct {
   int get_sib;
 } nr_mac_rrc_sched_sib_t;
 
+typedef struct {
+  nr_mac_ra_start_cause_t cause;
+} nr_mac_rrc_start_ra_t;
 
 enum payload_type {
   NR_MAC_RRC_CONFIG_RESET,
@@ -480,6 +484,7 @@ typedef struct {
     nr_mac_rrc_config_sib1_t config_sib1;
     nr_mac_rrc_sched_sib_t sched_sib;
     nr_mac_rrc_config_other_sib_t config_other_sib;
+    nr_mac_rrc_start_ra_t start_ra;
     nr_mac_rrc_resume_rb_t resume_rb;
   } payload;
 } nr_mac_rrc_message_t;

openair2/LAYER2/NR_MAC_UE/config_ue.c

@@ -1879,35 +1879,11 @@ void nr_rrc_mac_config_req_reset(module_id_t module_id, NR_UE_MAC_reset_cause_t
       release_mac_configuration(mac, cause);
       mac->state = UE_DETACHING;
       break;
-    case T300_EXPIRY:
-      reset_ra(mac, false);
-      reset_mac_inst(mac);
-      mac->state = UE_PERFORMING_RA; // still in sync but need to restart RA
-      break;
     case REJECT:
       reset_ra(mac, false);
       reset_mac_inst(mac);
       mac->state = UE_BARRED;
       break;
-    case RE_ESTABLISHMENT:
-      reset_mac_inst(mac);
-      nr_ue_mac_default_configs(mac);
-      nr_ue_reset_sync_state(mac, true);
-      release_mac_configuration(mac, cause);
-      // suspend all RBs except SRB0
-      for (int j = 0; j < mac->lc_ordered_list.count; j++) {
-        nr_lcordered_info_t *lc = mac->lc_ordered_list.array[j];
-        if (lc->rb.type == NR_LCID_SRB && lc->rb.choice.srb_id == 0)
-          continue;
-        lc->rb_suspended = true;
-      }
-      // apply the timeAlignmentTimerCommon included in SIB1
-      configure_timeAlignmentTimer(&mac->time_alignment_timer, mac->timeAlignmentTimerCommon, mac->current_UL_BWP->scs);
-      // new sync with old cell ID (re-establishment on the same cell)
-      sync_req.target_Nid_cell = mac->physCellId;
-      sync_req.ssb_bw_scan = false;
-      nr_ue_send_synch_request(mac, module_id, 0, &sync_req);
-      break;
     case RRC_SETUP_REESTAB_RESUME:
       release_mac_configuration(mac, cause);
       nr_ue_mac_default_configs(mac);
@@ -2042,6 +2018,50 @@ void nr_rrc_mac_config_req_paging_ue_id(module_id_t module_id, uint64_t fiveG_S_
   pthread_mutex_unlock(&mac->if_mutex);
 }
 
+static void nr_mac_start_ra(NR_UE_MAC_INST_t *mac, module_id_t module_id, nr_mac_ra_start_cause_t cause)
+{
+  switch (cause) {
+    case NR_MAC_RA_START_SETUP:
+    case NR_MAC_RA_START_T300:
+      reset_ra(mac, false);
+      reset_mac_inst(mac);
+      mac->msg3_C_RNTI = false;
+      mac->state = UE_PERFORMING_RA;
+      break;
+    case NR_MAC_RA_START_REESTABLISHMENT: {
+      fapi_nr_synch_request_t sync_req = {.target_Nid_cell = mac->physCellId, .ssb_bw_scan = false};
+      reset_mac_inst(mac);
+      nr_ue_mac_default_configs(mac);
+      nr_ue_reset_sync_state(mac, true);
+      release_mac_configuration(mac, RE_ESTABLISHMENT);
+      for (int j = 0; j < mac->lc_ordered_list.count; j++) {
+        nr_lcordered_info_t *lc = mac->lc_ordered_list.array[j];
+        if (lc->rb.type == NR_LCID_SRB && lc->rb.choice.srb_id == 0)
+          continue;
+        lc->rb_suspended = true;
+      }
+      configure_timeAlignmentTimer(&mac->time_alignment_timer, mac->timeAlignmentTimerCommon, mac->current_UL_BWP->scs);
+      nr_ue_send_synch_request(mac, module_id, 0, &sync_req);
+      break;
+    }
+    default:
+      AssertFatal(false, "unknown nr_mac_ra_start_cause_t %d\n", cause);
+  }
+}
+
+/** @brief All RRC-initiated RA entry points */
+void nr_rrc_mac_start_ra(module_id_t module_id, nr_mac_ra_start_cause_t cause)
+{
+  NR_UE_MAC_INST_t *mac = get_mac_inst(module_id);
+  int ret = pthread_mutex_lock(&mac->if_mutex);
+  AssertFatal(!ret, "mutex failed %d\n", ret);
+
+  nr_mac_start_ra(mac, module_id, cause);
+
+  ret = pthread_mutex_unlock(&mac->if_mutex);
+  AssertFatal(!ret, "mutex failed %d\n", ret);
+}
+
 void nr_rrc_mac_config_req_sib1(module_id_t module_id, int cc_idP, NR_SIB1_t *sib1, bool can_start_ra)
 {
   NR_UE_MAC_INST_t *mac = get_mac_inst(module_id);

openair2/LAYER2/NR_MAC_UE/mac_defs.h

@@ -177,7 +177,6 @@ typedef struct {
 typedef enum {
   GO_TO_IDLE,
   DETACH,
-  T300_EXPIRY,
   RE_ESTABLISHMENT,
   RRC_SETUP_REESTAB_RESUME,
   UL_SYNC_LOST_T430_EXPIRED,

openair2/LAYER2/NR_MAC_UE/mac_proto.h

@@ -67,6 +67,7 @@ void nr_rrc_mac_config_req_mib(module_id_t module_id, int cc_idP, NR_MIB_t *mibP
 void nr_rrc_mac_sched_sib(module_id_t module_id, int sched_sib);
 void nr_rrc_mac_config_req_sib1(module_id_t module_id, int cc_idP, NR_SIB1_t *sib1, bool can_start_ra);
 void nr_rrc_mac_config_req_paging_ue_id(module_id_t module_id, uint64_t fiveG_S_TMSI);
+void nr_rrc_mac_start_ra(module_id_t module_id, nr_mac_ra_start_cause_t cause);
 
 struct position; /* forward declaration */
 void nr_rrc_mac_config_other_sib(module_id_t module_id, NR_SIB19_r17_t *sib19_r17, int hfn, int frame, bool can_start_ra);

openair2/RRC/NR_UE/L2_interface_ue.c

@@ -144,6 +144,9 @@ void process_msg_rcc_to_mac(nr_mac_rrc_message_t *msg, int instance_id)
                                   msg->payload.config_other_sib.frame,
                                   msg->payload.config_other_sib.can_start_ra);
     } break;
+    case NR_MAC_RRC_START_RA:
+      nr_rrc_mac_start_ra(instance_id, msg->payload.start_ra.cause);
+      break;
     case NR_MAC_RRC_SCHED_SIB:
       nr_rrc_mac_sched_sib(instance_id, msg->payload.sched_sib.get_sib);
       break;

openair2/RRC/NR_UE/nr_mac_rrc_types.h

@@ -0,0 +1,14 @@
+/*
+ * SPDX-License-Identifier: LicenseRef-CSSL-1.0
+ */
+
+#ifndef NR_MAC_RRC_TYPES_H_
+#define NR_MAC_RRC_TYPES_H_
+
+typedef enum {
+  NR_MAC_RA_START_SETUP,
+  NR_MAC_RA_START_T300,
+  NR_MAC_RA_START_REESTABLISHMENT,
+} nr_mac_ra_start_cause_t;
+
+#endif /* NR_MAC_RRC_TYPES_H_ */

openair2/RRC/NR_UE/rrc_UE.c

@@ -128,6 +128,17 @@ static void nr_rrc_send_msg_to_mac(NR_UE_RRC_INST_t *rrc, nr_mac_rrc_message_t *
   pushNotifiedFIFO(rrc->mac_input_nf, nf_msg);
 }
 
+/** @brief Ask MAC to start or restart random access
+ * @param rrc   UE RRC instance
+ * @param cause Why RA is started (setup, T300, post-SIB, re-establishment) */
+static void nr_rrc_trigger_mac_ra(NR_UE_RRC_INST_t *rrc, nr_mac_ra_start_cause_t cause)
+{
+  nr_mac_rrc_message_t rrc_msg = {0};
+  rrc_msg.payload_type = NR_MAC_RRC_START_RA;
+  rrc_msg.payload.start_ra.cause = cause;
+  nr_rrc_send_msg_to_mac(rrc, &rrc_msg);
+}
+
 NR_UE_RRC_INST_t *get_NR_UE_rrc_inst(int instance)
 {
   AssertFatal(instance >= 0 && instance < MAX_NUM_NR_UE_INST, "RRC instance %d out of bounds\n", instance);
@@ -3356,10 +3367,7 @@ static void nr_rrc_initiate_rrcReestablishment(NR_UE_RRC_INST_t *rrc, NR_Reestab
   // reset MAC
   // release spCellConfig, if configured
   // perform cell selection in accordance with the cell selection process
-  nr_mac_rrc_message_t rrc_msg = {0};
-  rrc_msg.payload_type = NR_MAC_RRC_CONFIG_RESET;
-  rrc_msg.payload.config_reset.cause = RE_ESTABLISHMENT;
-  nr_rrc_send_msg_to_mac(rrc, &rrc_msg);
+  nr_rrc_trigger_mac_ra(rrc, NR_MAC_RA_START_REESTABLISHMENT);
 }
 
 void handle_RRCRelease(NR_UE_RRC_INST_t *rrc)
@@ -3579,12 +3587,7 @@ void handle_t300_expiry(NR_UE_RRC_INST_t *rrc)
   rrc->ra_trigger = RRC_CONNECTION_SETUP;
   nr_rrc_ue_prepare_RRCSetupRequest(rrc);
 
-  // reset MAC, release the MAC configuration
-  NR_UE_MAC_reset_cause_t cause = T300_EXPIRY;
-  nr_mac_rrc_message_t rrc_msg = {0};
-  rrc_msg.payload_type = NR_MAC_RRC_CONFIG_RESET;
-  rrc_msg.payload.config_reset.cause = cause;
-  nr_rrc_send_msg_to_mac(rrc, &rrc_msg);
+  nr_rrc_trigger_mac_ra(rrc, NR_MAC_RA_START_T300);
 
   // TODO handle connEstFailureControl
   // TODO inform upper layers about the failure to establish the RRC connection

openair2/RRC/NR_UE/rrc_defs.h

@@ -40,6 +40,7 @@
 #include "as_message.h"
 #include "common/utils/nr/nr_common.h"
 #include "notified_fifo.h"
+#include "RRC/NR_UE/nr_mac_rrc_types.h"
 
 #define NB_CNX_UE 2//MAX_MANAGED_RG_PER_MOBILE
 #define MAX_MEAS_OBJ 64