nimble/transport/nrf53: Move RX from interrupt to task

This adds option to move RX from interrupt to task. This is enforced if
monitor is used since montor code cannot be used from interrupts.

nimble/transport/nrf5340/src/nrf5340_ble_hci.c

@@ -36,6 +36,20 @@
 
 static struct hci_ipc_sm g_hci_ipc_sm;
 
+static void
+rx_func(void *arg)
+{
+    uint8_t *buf;
+    int len;
+
+    len = ipc_nrf5340_available_buf(IPC_RX_CHANNEL, (void **)&buf);
+    while (len > 0) {
+        len = hci_ipc_rx(&g_hci_ipc_sm, buf, len);
+        ipc_nrf5340_consume(IPC_RX_CHANNEL, len);
+        len = ipc_nrf5340_available_buf(IPC_RX_CHANNEL, (void **)&buf);
+    }
+}
+
 static int
 nrf5340_ble_hci_acl_tx(struct os_mbuf *om)
 {
@@ -95,22 +109,23 @@ nrf5340_ble_hci_iso_tx(struct os_mbuf *om)
 static void
 nrf5340_ble_hci_trans_rx(int channel, void *user_data)
 {
-    uint8_t *buf;
-    int len;
+    assert(channel == IPC_RX_CHANNEL);
 
-    len = ipc_nrf5340_available_buf(channel, (void **)&buf);
-    while (len > 0) {
-        len = hci_ipc_rx(&g_hci_ipc_sm, buf, len);
-        ipc_nrf5340_consume(channel, len);
-        len = ipc_nrf5340_available_buf(channel, (void **)&buf);
-    }
+#if MYNEWT_VAL(BLE_TRANSPORT_NRF5340_RX_TASK)
+    ble_transport_rx();
+#else
+    rx_func(NULL);
+#endif
 }
 
 static void
 nrf5340_ble_hci_init(void)
 {
     SYSINIT_ASSERT_ACTIVE();
 
+#if MYNEWT_VAL(BLE_TRANSPORT_NRF5340_RX_TASK)
+    ble_transport_rx_register(rx_func, NULL);
+#endif
     ipc_nrf5340_recv(IPC_RX_CHANNEL, nrf5340_ble_hci_trans_rx, NULL);
 }
 

nimble/transport/nrf5340/syscfg.yml

@@ -0,0 +1,27 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#  http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
+syscfg.defs:
+    BLE_TRANSPORT_NRF5340_RX_TASK:
+        description: >
+            Use separate task for RX. This is required and enabled by default
+            if monitor is used, optional otherwise.
+        value: 0
+
+syscfg.vals.BLE_MONITOR:
+    BLE_TRANSPORT_NRF5340_RX_TASK: 1
+    BLE_TRANSPORT_RX_STACK_SIZE: 120