Makes possible to reset the modem if connection dropped

Earlier internal state stayed consistent if connection drop happened by
calling disconnect(). Now spontaneous disconnect updates also the
drivers internal state.

Author: Veijo Pesonen

ESP8266/ESP8266.cpp

@@ -238,9 +238,6 @@ nsapi_error_t ESP8266::connect(const char *ap, const char *passPhrase)
 {
     _smutex.lock();
     set_timeout(ESP8266_CONNECT_TIMEOUT);
-    _connection_status = NSAPI_STATUS_CONNECTING;
-    if(_connection_status_cb)
-        _connection_status_cb(NSAPI_EVENT_CONNECTION_STATUS_CHANGE, _connection_status);
 
     _parser.send("AT+CWJAP_CUR=\"%s\",\"%s\"", ap, passPhrase);
     if (!_parser.recv("OK\n")) {
@@ -783,6 +780,11 @@ void ESP8266::attach(mbed::Callback<void(nsapi_event_t, intptr_t)> status_cb)
     _connection_status_cb = status_cb;
 }
 
+void ESP8266::attach_int(mbed::Callback<void()> status_cb)
+{
+    _conn_state_drv_cb = status_cb;
+}
+
 bool ESP8266::_recv_ap(nsapi_wifi_ap_t *ap)
 {
     int sec;
@@ -856,16 +858,28 @@ void ESP8266::_oob_connection_status()
 {
     char status[13];
     if (_parser.recv("%12[^\"]\n", status)) {
-        if (strcmp(status, "GOT IP\n") == 0)
+        if (strcmp(status, "GOT IP\n") == 0) {
             _connection_status = NSAPI_STATUS_GLOBAL_UP;
-        else if (strcmp(status, "DISCONNECT\n") == 0)
+        } else if (strcmp(status, "DISCONNECT\n") == 0) {
             _connection_status = NSAPI_STATUS_DISCONNECTED;
-        else
-            return;
+        } else if (strcmp(status, "CONNECTED\n") == 0) {
+            _connection_status = NSAPI_STATUS_CONNECTING;
+        } else {
+            MBED_ERROR(MBED_MAKE_ERROR(MBED_MODULE_DRIVER, MBED_ERROR_CODE_EBADMSG), \
+                    "ESP8266::_oob_connection_status: invalid AT cmd\n");
+        }
+    } else {
+        MBED_ERROR(MBED_MAKE_ERROR(MBED_MODULE_DRIVER, MBED_ERROR_CODE_ENOMSG), \
+                "ESP8266::_oob_connection_status: network status timed out\n");
+    }
+
+    //debug("ESP8266::_oob_connection_status: network state changed to WIFI \"%s\" (%d)\n", status, _connection_status);
 
-        if(_connection_status_cb)
-            _connection_status_cb(NSAPI_EVENT_CONNECTION_STATUS_CHANGE, _connection_status);
+    if(_connection_status_cb) {
+        _connection_status_cb(NSAPI_EVENT_CONNECTION_STATUS_CHANGE, _connection_status);
     }
+
+    _conn_state_drv_cb();
 }
 
 int8_t ESP8266::default_wifi_mode()

ESP8266/ESP8266.h

@@ -294,12 +294,24 @@ class ESP8266
     }
 
     /**
-    * Attach a function to call whenever network state has changed
+    * Attach a function to call whenever network state has changed. Driver external
     *
     * @param func A pointer to a void function, or 0 to set as none
     */
     void attach(mbed::Callback<void(nsapi_event_t, intptr_t)> status_cb);
 
+    /**
+    * Attach a function to call whenever network state has changed. Driver internal
+    *
+    * @param func A pointer to a void function, or 0 to set as none
+    */
+    void attach_int(mbed::Callback<void()> status_cb);
+
+    template <typename T, typename M>
+    void attach_int(T *obj, M method) {
+        attach_int(Callback<void()>(obj, method));
+    }
+
     /**
      * Read default Wifi mode from flash
      *
@@ -412,7 +424,8 @@ class ESP8266
 
     // Connection state reporting
     nsapi_connection_status_t _connection_status;
-    Callback<void(nsapi_event_t, intptr_t)> _connection_status_cb;
+    Callback<void(nsapi_event_t, intptr_t)> _connection_status_cb; // Application registered
+    Callback<void()> _conn_state_drv_cb; // ESP8266Interface registered
 };
 
 #endif

ESP8266Interface.cpp

@@ -51,6 +51,7 @@ ESP8266Interface::ESP8266Interface()
 
     _esp.sigio(this, &ESP8266Interface::event);
     _esp.set_timeout();
+    _esp.attach_int(this, &ESP8266Interface::update_conn_state_cb);
 }
 
 // ESP8266Interface implementation
@@ -68,6 +69,7 @@ ESP8266Interface::ESP8266Interface(PinName tx, PinName rx, bool debug, PinName r
 
     _esp.sigio(this, &ESP8266Interface::event);
     _esp.set_timeout();
+    _esp.attach_int(this, &ESP8266Interface::update_conn_state_cb);
 }
 
 int ESP8266Interface::connect(const char *ssid, const char *pass, nsapi_security_t security,
@@ -586,3 +588,23 @@ WiFiInterface *WiFiInterface::get_default_instance() {
 }
 
 #endif
+
+void ESP8266Interface::update_conn_state_cb()
+{
+    switch(_esp.connection_status()) {
+        // Doesn't require changes
+        case NSAPI_STATUS_CONNECTING:
+        case NSAPI_STATUS_GLOBAL_UP:
+            break;
+        // Start from scratch if connection drops/is dropped
+        case NSAPI_STATUS_DISCONNECTED:
+            _started = false;
+            _initialized = false;
+            break;
+        // Handled on AT layer
+        case NSAPI_STATUS_LOCAL_UP:
+        case NSAPI_STATUS_ERROR_UNSUPPORTED:
+        default:
+            break;
+    }
+}

ESP8266Interface.h

@@ -333,6 +333,7 @@ class ESP8266Interface : public NetworkStack, public WiFiInterface
 
     bool _disable_default_softap();
     void event();
+    void update_conn_state_cb();
     bool _get_firmware_ok();
     nsapi_error_t _init(void);
     nsapi_error_t _startup(const int8_t wifi_mode);