wireless/bluetooth: Support removable bluetooth modules.

This bluetooth stack remains in an inconsistent state when
the bluetooth HCI module is removed. This change adds a
bt_netdev_unregister function that can be used to clean up
after a module is removed. Some global variables are also
set to their default values.

Author: ldube

include/nuttx/wireless/bluetooth/bt_driver.h

@@ -119,4 +119,21 @@ struct bt_driver_s
 
 int bt_netdev_register(FAR struct bt_driver_s *btdev);
 
+/****************************************************************************
+ * Name: bt_netdev_unregister
+ *
+ * Description:
+ *   Unregister a network driver registered by bt_netdev_register.
+ *
+ * Input Parameters:
+ *   btdev - An instance of the low-level driver interface structure.
+ *
+ * Returned Value:
+ *   Zero (OK) is returned on success.  Otherwise a negated errno value is
+ *   returned to indicate the nature of the failure.
+ *
+ ****************************************************************************/
+
+int bt_netdev_unregister(FAR struct bt_driver_s *btdev);
+
 #endif /* __INCLUDE_NUTTX_WIRELESS_BLUETOOTH_BT_DRIVER_H */

wireless/bluetooth/bt_att.c

@@ -1846,6 +1846,8 @@ void bt_att_initialize(void)
     .disconnected = bt_att_disconnected,
   };
 
+  memset(g_bt_att_pool, 0, sizeof(g_bt_att_pool));
+
   bt_l2cap_chan_register(&chan);
 }
 

wireless/bluetooth/bt_conn.c

@@ -1078,3 +1078,22 @@ int bt_conn_le_conn_update(FAR struct bt_conn_s *conn, uint16_t min,
 
   return bt_hci_cmd_send(BT_HCI_OP_LE_CONN_UPDATE, buf);
 }
+
+/****************************************************************************
+ * Name: bt_conn_initialize
+ *
+ * Description:
+ *   Initialize this module's private data.
+ *
+ * Input Parameters:
+ *   None
+ *
+ * Returned Value:
+ *   None
+ *
+ ****************************************************************************/
+
+void bt_conn_initialize(void)
+{
+  memset(g_conns, 0, sizeof(g_conns));
+}

wireless/bluetooth/bt_conn.h

@@ -416,4 +416,6 @@ int bt_conn_le_conn_update(FAR struct bt_conn_s *conn, uint16_t min,
                            uint16_t max, uint16_t latency,
                            uint16_t timeout);
 
+void bt_conn_initialize(void);
+
 #endif /* __WIRELESS_BLUETOOTH_BT_CONN_H */

wireless/bluetooth/bt_hcicore.c

@@ -985,7 +985,7 @@ static int hci_tx_kthread(int argc, FAR char *argv[])
 
   wlinfo("started\n");
 
-  for (; ; )
+  for (; g_btdev.tx_status == OK; )
     {
       FAR struct bt_buf_s *buf;
 
@@ -1016,16 +1016,25 @@ static int hci_tx_kthread(int argc, FAR char *argv[])
           g_btdev.sent_cmd = NULL;
         }
 
-      g_btdev.sent_cmd = bt_buf_addref(buf);
+      /* Allow transmission if module is connected. */
 
-      wlinfo("Sending command %04x buf %p to driver\n",
-             buf->u.hci.opcode, buf);
+      if (g_btdev.tx_status == OK)
+        {
+          g_btdev.sent_cmd = bt_buf_addref(buf);
+
+          wlinfo("Sending command %04x buf %p to driver\n",
+                 buf->u.hci.opcode, buf);
+
+          bt_send(btdev, buf);
+        }
 
-      bt_send(btdev, buf);
       bt_buf_release(buf);
     }
 
-  return EXIT_SUCCESS;  /* Can't get here */
+  /* Acknowledge the termination request. */
+
+  g_btdev.tx_status = ESHUTDOWN;
+  return EXIT_SUCCESS;
 }
 
 /****************************************************************************
@@ -1425,6 +1434,64 @@ static int hci_initialize(void)
   nxsem_init(&g_btdev.le_pkts_sem, 0, g_btdev.le_pkts);
   return 0;
 }
+
+/****************************************************************************
+ * Name: cmd_queue_deinit
+ *
+ * Description:
+ *   Threads, fifos and semaphores deinitialization
+ *
+ * Input Parameters:
+ *   none
+ *
+ * Returned Value:
+ *   None
+ *
+ ****************************************************************************/
+
+static void cmd_queue_deinit(void)
+{
+  int ret;
+  FAR struct bt_buf_s *buf;
+
+  /* Tell the tx thread that the module is disconnected.
+   */
+
+  g_btdev.tx_status = ENOTCONN;
+
+  /* Make sure the thread is not blocked by the semaphore.
+   */
+
+  nxsem_post(&g_btdev.ncmd_sem);
+
+  /* We create and push a packet into the tx queue to unblock the thread.
+   * Any packet will do.
+   */
+
+  buf = bt_hci_cmd_create(BT_HCI_OP_RESET, 0);
+  if (buf)
+    {
+      ret = bt_queue_send(&g_btdev.tx_queue, buf, BT_NORMAL_PRIO);
+      if (ret < 0)
+        {
+          wlerr("ERROR: bt_queue_send() failed: %d\n", ret);
+        }
+    }
+
+  /* Wait for the tx thread to exit gracefully. */
+
+  while (g_btdev.tx_status == ENOTCONN)
+    {
+      nxsig_usleep(1000);
+    }
+
+  /* Deinitialization */
+
+  nxsem_destroy(&g_btdev.ncmd_sem);
+  file_mq_close(&g_btdev.tx_queue);
+  work_cancel(HPWORK, &g_hp_work);
+  work_cancel(LPWORK, &g_lp_work);
+}
 #endif
 
 /* threads, fifos and semaphores initialization */
@@ -1444,6 +1511,7 @@ static void cmd_queue_init(void)
   nxsem_init(&g_btdev.ncmd_sem, 0, 1);
 
   g_btdev.ncmd = 1;
+  g_btdev.tx_status = OK;
   ret = kthread_create("BT HCI Tx", CONFIG_BLUETOOTH_TXCMD_PRIORITY,
                        CONFIG_BLUETOOTH_TXCMD_STACKSIZE,
                        hci_tx_kthread, NULL);
@@ -1497,6 +1565,14 @@ int bt_initialize(void)
 
   wlinfo("btdev %p\n", btdev);
 
+#ifdef CONFIG_WIRELESS_BLUETOOTH_HOST
+  g_callback_list = NULL;
+  g_scan_dev_found_cb = NULL;
+#endif
+
+  memset(&g_lp_rxlist, 0, sizeof(g_lp_rxlist));
+  memset(&g_hp_rxlist, 0, sizeof(g_hp_rxlist));
+
   DEBUGASSERT(btdev != NULL);
   bt_buf_initialize();
 
@@ -1505,6 +1581,9 @@ int bt_initialize(void)
   ret = btdev->open(btdev);
   if (ret < 0)
     {
+#ifdef CONFIG_WIRELESS_BLUETOOTH_HOST
+      cmd_queue_deinit();
+#endif
       wlerr("ERROR: HCI driver open failed (%d)\n", ret);
       return ret;
     }
@@ -1513,6 +1592,7 @@ int bt_initialize(void)
   ret = hci_initialize();
   if (ret < 0)
     {
+      cmd_queue_deinit();
       wlerr("ERROR:  hci_initialize failed: %d\n", ret);
       return ret;
     }
@@ -1523,6 +1603,38 @@ int bt_initialize(void)
   return ret;
 }
 
+/****************************************************************************
+ * Name: bt_deinitialize
+ *
+ * Description:
+ *   Deinitialize Bluetooth.
+ *
+ * Returned Value:
+ *    Zero on success or (negative) error code otherwise.
+ *
+ ****************************************************************************/
+
+int bt_deinitialize(void)
+{
+#ifdef CONFIG_WIRELESS_BLUETOOTH_HOST
+  FAR struct bt_driver_s *btdev = g_btdev.btdev;
+
+  cmd_queue_deinit();
+
+  /* Call the bluetooth HCI driver's close function if available. */
+
+  if (btdev)
+    {
+      if (btdev->close)
+        {
+          btdev->close(btdev);
+        }
+    }
+#endif
+
+  return OK;
+}
+
 /****************************************************************************
  * Name: bt_driver_register
  *
@@ -1552,6 +1664,8 @@ int bt_driver_register(FAR struct bt_driver_s *btdev)
       return -EALREADY;
     }
 
+  memset(&g_btdev, 0, sizeof(g_btdev));
+
   g_btdev.btdev = btdev;
   return 0;
 }

wireless/bluetooth/bt_hcicore.h

@@ -100,6 +100,10 @@ struct bt_dev_s
   sem_t le_pkts_sem;
 #endif
 
+  /* TX thread status */
+
+  int tx_status;
+
   /* Number of commands controller can accept */
 
   uint8_t ncmd;
@@ -255,6 +259,19 @@ struct bt_eir_s; /* Forward reference */
 
 int bt_initialize(void);
 
+/****************************************************************************
+ * Name: bt_deinitialize
+ *
+ * Description:
+ *   Deinitialize Bluetooth.
+ *
+ * Returned Value:
+ *    Zero on success or (negative) error code otherwise.
+ *
+ ****************************************************************************/
+
+int bt_deinitialize(void);
+
 /****************************************************************************
  * Name: bt_driver_register
  *

wireless/bluetooth/bt_l2cap.c

@@ -454,6 +454,10 @@ int bt_l2cap_init(void)
     .receive = le_sig,
   };
 
+  g_channels = NULL;
+  g_default = NULL;
+
+  bt_conn_initialize();
   bt_att_initialize();
 
   ret = bt_smp_initialize();

wireless/bluetooth/bt_netdev.c

@@ -1315,9 +1315,63 @@ int bt_netdev_register(FAR struct bt_driver_s *btdev)
 
 errout:
 
+  btnet_ifdown(netdev);
+  bt_driver_unregister(btdev);
+
   /* Free memory and return the error */
 
-  kmm_free(priv);
+  kmm_free(btdev->bt_net);
+  btdev->bt_net = NULL;
+  return ret;
+}
+
+/****************************************************************************
+ * Name: bt_netdev_unregister
+ *
+ * Description:
+ *   Unregister a network a driver registered by bt_netdev_register.
+ *
+ * Input Parameters:
+ *   btdev - An instance of the low-level driver interface structure.
+ *
+ * Returned Value:
+ *   Zero (OK) is returned on success.  Otherwise a negated errno value is
+ *   returned to indicate the nature of the failure.
+ *
+ ****************************************************************************/
+
+int bt_netdev_unregister(FAR struct bt_driver_s *btdev)
+{
+  int ret;
+  FAR struct btnet_driver_s *priv;
+
+  if (!btdev)
+    {
+      return -EINVAL;
+    }
+
+  priv = (FAR struct btnet_driver_s *)btdev->bt_net;
+  if (!priv)
+    {
+      nerr("ERROR: bt_driver_s is probably not registered\n");
+      return -EINVAL;
+    }
+
+  btnet_ifdown(&priv->bd_dev.r_dev);
+
+  ret = netdev_unregister(&priv->bd_dev.r_dev);
+  if (ret < 0)
+    {
+      nerr("ERROR: netdev_unregister bfailed: %d\n", ret);
+    }
+
+  bt_deinitialize();
+
+  bt_driver_unregister(btdev);
+
+  kmm_free(btdev->bt_net);
+  btdev->bt_net = NULL;
+
   return ret;
 }
 

wireless/bluetooth/bt_smp.c

@@ -1584,6 +1584,8 @@ int bt_smp_initialize(void)
     .encrypt_change = bt_smp_encrypt_change,
   };
 
+  memset(g_smp_pool, 0, sizeof(g_smp_pool));
+
   bt_l2cap_chan_register(&chan);
 
   return smp_self_test();