Mynewt: Stop the host on system shutdown

This is Mynewt-only feature.  When the system is shutting down, the host
stops.

nimble/host/include/host/ble_hs.h

@@ -364,6 +364,17 @@ void ble_hs_evq_set(struct ble_npl_eventq *evq);
  */
 void ble_hs_init(void);
 
+/**
+ * @brief Called when the system is shutting down.  Stops the BLE host.
+ *
+ * @param reason                The reason for the shutdown.  One of the
+ *                                  HAL_RESET_[...] codes or an
+ *                                  implementation-defined value.
+ *
+ * @return                      SYSDOWN_IN_PROGRESS. 
+ */
+int ble_hs_shutdown(int reason);
+
 #ifdef __cplusplus
 }
 #endif

nimble/host/pkg.yml

@@ -50,3 +50,6 @@ pkg.req_apis:
 
 pkg.init:
     ble_hs_init: 200
+
+pkg.down.BLE_HS_STOP_ON_SHUTDOWN:
+    ble_hs_shutdown: 200

nimble/host/src/ble_hs_shutdown.c

@@ -0,0 +1,69 @@
+/*
+ * 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.
+ */
+
+#if MYNEWT
+
+#include "os/mynewt.h"
+#include "ble_hs_priv.h"
+
+static struct ble_hs_stop_listener ble_hs_shutdown_stop_listener;
+
+/**
+ * Called when the host stop procedure has completed.
+ */
+static void
+ble_hs_shutdown_stop_cb(int status, void *arg)
+{
+    SYSDOWN_ASSERT_ACTIVE();
+
+    /* Indicate to sysdown that the host is fully shut down. */
+    sysdown_release();
+}
+
+int
+ble_hs_shutdown(int reason)
+{
+    int rc;
+
+    /* Ensure this function only gets called by sysdown. */
+    SYSDOWN_ASSERT_ACTIVE();
+
+    /* Initiate a host stop procedure. */
+    rc = ble_hs_stop(&ble_hs_shutdown_stop_listener, ble_hs_shutdown_stop_cb,
+                     NULL);
+    switch (rc) {
+    case 0:
+        /* Stop initiated.  Wait for result to be reported asynchronously. */
+        return SYSDOWN_IN_PROGRESS;
+
+    case BLE_HS_EBUSY:
+        /* Already stopping.  Wait for result to be reported asynchronously. */
+        return SYSDOWN_IN_PROGRESS;
+
+    case BLE_HS_EALREADY:
+        /* Already stopped.  Shutdown complete. */
+        return SYSDOWN_COMPLETE;
+
+    default:
+        BLE_HS_LOG(ERROR, "ble_hs_shutdown: failed to stop host; rc=%d\n", rc);
+        return SYSDOWN_COMPLETE;
+    }
+}
+
+#endif

nimble/host/syscfg.yml

@@ -422,5 +422,12 @@ syscfg.defs:
             a necessary workaround when interfacing with some controllers.
         value: 0
 
+    BLE_HS_STOP_ON_SHUTDOWN:
+        description: >
+            Stops the Bluetooth host when the system shuts down.  Stopping
+            entails aborting all GAP procedures and terminating open
+            connections.
+        value: 1
+
 syscfg.vals.BLE_MESH:
     BLE_SM_SC: 1