Cellular: Remove support for multiple ATHandlers

Major changes:
- Dependency to FileHandle removed from base classes
- AT_CellularDevice owns the default FileHandle and shares it with AT -classes
- Hang-up -detection moved as CellularContext::configure_hup(). Cannot be configured via CellularDevice any more.

Result on NRF52840_DK + BG96:
GCC:
Total Static RAM memory (data + bss): 29360(+296) bytes
Total Flash memory (text + data): 130660(-832) bytes

ARM:
Total Static RAM memory (data + bss): 261554(+8) bytes
Total Flash memory (text + data): 127573(-1193) bytes

IAR:
Total Static RAM memory (data + bss): 25479(+296) bytes
Total Flash memory (text + data): 102418(-527) bytes

RAM increase is because now ATHandler is no longer created with new -operator but is now member of AT_CellularDevice,
so image tool is able to count it. Actually total RAM consumption has decreased due to removed variables.

UNITTESTS/features/cellular/framework/AT/at_cellularcontext/at_cellularcontexttest.cpp

@@ -44,7 +44,6 @@ protected:
         ATHandler_stub::nsapi_error_value = 0;
         ATHandler_stub::nsapi_error_ok_counter = 0;
         ATHandler_stub::int_value = -1;
-        ATHandler_stub::ref_count = 0;
         ATHandler_stub::timeout = 0;
         ATHandler_stub::default_timeout = 0;
         ATHandler_stub::debug_on = 0;
@@ -514,21 +513,6 @@ TEST_F(TestAT_CellularContext, get_apn_backoff_timer)
     ASSERT_EQ(time, 55);
 }
 
-TEST_F(TestAT_CellularContext, set_file_handle)
-{
-    EventQueue que;
-    FileHandle_stub fh1;
-    ATHandler at(&fh1, que, 0, ",");
-    AT_CellularDevice dev(&fh1);
-    AT_CellularContext ctx(at, &dev);
-    ctx.set_file_handle(&fh1);
-
-    BufferedSerial ss(NC, NC);
-
-    ctx.set_file_handle(&ss, PTC0, true);
-    ctx.enable_hup(true);
-}
-
 TEST_F(TestAT_CellularContext, connect_disconnect_sync)
 {
     EventQueue que;

UNITTESTS/features/cellular/framework/AT/at_cellulardevice/at_cellulardevicetest.cpp

@@ -28,20 +28,14 @@ protected:
 
     void SetUp()
     {
-        EventQueue que;
-        FileHandle_stub fh1;
         filehandle_stub_table = NULL;
         filehandle_stub_table_pos = 0;
 
-        ATHandler at(&fh1, que, 0, ",");
-        ATHandler_stub::handler = &at;
-
         ATHandler_stub::read_string_index = kRead_string_table_size;
     }
 
     void TearDown()
     {
-        ATHandler_stub::handler = NULL;
     }
 };
 
@@ -55,33 +49,15 @@ TEST_F(TestAT_CellularDevice, Create)
 
     EXPECT_TRUE(dev2 != NULL);
     delete dev2;
-    ATHandler *at = dev.get_at_handler(&fh1);
+    ATHandler *at = dev.get_at_handler();
-    dev.release_at_handler(at);
-    dev.release_at_handler(at);
 }
 
 TEST_F(TestAT_CellularDevice, test_AT_CellularDevice_get_at_handler)
 {
     FileHandle_stub fh1;
-    FileHandle_stub fh2;
+    AT_CellularDevice dev(&fh1);
-    FileHandle_stub fh3;
+    ATHandler *at = dev.get_at_handler();
-    AT_CellularDevice dev(&fh1); // AT fh1 ref count 1
+    EXPECT_TRUE(at->get_file_handle() == &fh1);
-
-    EXPECT_TRUE(dev.open_network(&fh1)); // AT fh1 ref count 2
-    dev.modem_debug_on(true);
-    EXPECT_TRUE(dev.open_sms(&fh2));
-    EXPECT_TRUE(dev.open_information(&fh3));
-    ATHandler_stub::fh_value = &fh1;
-
-    ATHandler_stub::fh_value = NULL;
-
-    AT_CellularDevice *dev2 = new AT_CellularDevice(&fh1); // AT fh1 ref count 3
-    EXPECT_TRUE(dev2->open_information(&fh1)); // AT fh1 ref count 4
-    ATHandler *at = dev2->get_at_handler(); // AT fh1 ref count 5
-    delete dev2; // AT fh1 2 refs deleted -> ref count 3
-
-    AT_CellularDevice dev3(&fh1); // AT fh1 ref count 4
-    EXPECT_TRUE(dev3.release_at_handler(at) == NSAPI_ERROR_OK); // AT fh1 ref count 3
 }
 
 TEST_F(TestAT_CellularDevice, test_AT_CellularDevice_open_network)
@@ -89,12 +65,8 @@ TEST_F(TestAT_CellularDevice, test_AT_CellularDevice_open_network)
     FileHandle_stub fh1;
     AT_CellularDevice dev(&fh1);
 
-    CellularNetwork *nw = dev.open_network(NULL);
+    CellularNetwork *nw = dev.open_network();
-    CellularNetwork *nw1 = dev.open_network(&fh1);
-
     EXPECT_TRUE(nw);
-    EXPECT_TRUE(nw1);
-    EXPECT_TRUE(nw1 == nw);
 }
 
 TEST_F(TestAT_CellularDevice, test_AT_CellularDevice_open_sms)
@@ -102,12 +74,8 @@ TEST_F(TestAT_CellularDevice, test_AT_CellularDevice_open_sms)
     FileHandle_stub fh1;
     AT_CellularDevice dev(&fh1);
 
-    CellularSMS *sms = dev.open_sms(NULL);
+    CellularSMS *sms = dev.open_sms();
-    CellularSMS *sms1 = dev.open_sms(&fh1);
-
     EXPECT_TRUE(sms);
-    EXPECT_TRUE(sms1);
-    EXPECT_TRUE(sms1 == sms);
 }
 
 TEST_F(TestAT_CellularDevice, test_AT_CellularDevice_open_information)
@@ -115,12 +83,8 @@ TEST_F(TestAT_CellularDevice, test_AT_CellularDevice_open_information)
     FileHandle_stub fh1;
     AT_CellularDevice dev(&fh1);
 
-    CellularInformation *info = dev.open_information(NULL);
+    CellularInformation *info = dev.open_information();
-    CellularInformation *info1 = dev.open_information(&fh1);
-
     EXPECT_TRUE(info);
-    EXPECT_TRUE(info1);
-    EXPECT_TRUE(info1 == info);
 }
 
 TEST_F(TestAT_CellularDevice, test_AT_CellularDevice_close_network)
@@ -128,9 +92,7 @@ TEST_F(TestAT_CellularDevice, test_AT_CellularDevice_close_network)
     FileHandle_stub fh1;
     AT_CellularDevice dev(&fh1);
 
-    EXPECT_TRUE(dev.open_network(&fh1));
+    EXPECT_TRUE(dev.open_network());
-    EXPECT_EQ(ATHandler_stub::ref_count, 1);
-
     dev.close_network();
 }
 
@@ -139,9 +101,7 @@ TEST_F(TestAT_CellularDevice, test_AT_CellularDevice_close_sms)
     FileHandle_stub fh1;
     AT_CellularDevice dev(&fh1);
 
-    EXPECT_TRUE(dev.open_sms(&fh1));
+    EXPECT_TRUE(dev.open_sms());
-    EXPECT_EQ(ATHandler_stub::ref_count, 1);
-
     dev.close_sms();
 }
 
@@ -151,14 +111,14 @@ TEST_F(TestAT_CellularDevice, test_AT_CellularDevice_close_information)
     AT_CellularDevice dev(&fh1);
     ATHandler_stub::int_value = 0;
 
-    EXPECT_TRUE(dev.open_information(&fh1));
+    EXPECT_TRUE(dev.open_information());
 
     ATHandler_stub::fh_value = NULL;
     dev.close_information();
 
     ATHandler_stub::fh_value = &fh1;
 
-    EXPECT_TRUE(dev.open_information(&fh1));
+    EXPECT_TRUE(dev.open_information());
 
     dev.close_information();
 
@@ -176,8 +136,7 @@ TEST_F(TestAT_CellularDevice, test_AT_CellularDevice_set_timeout)
     EXPECT_TRUE(ATHandler_stub::timeout == 5000);
     EXPECT_TRUE(ATHandler_stub::default_timeout == true);
 
-    EXPECT_TRUE(dev.open_sms(&fh1));
+    EXPECT_TRUE(dev.open_sms());
-    EXPECT_EQ(ATHandler_stub::ref_count, 1);
 
     dev.set_timeout(5000);
     EXPECT_TRUE(ATHandler_stub::timeout == 5000);
@@ -195,8 +154,7 @@ TEST_F(TestAT_CellularDevice, test_AT_CellularDevice_modem_debug_on)
     dev.modem_debug_on(true);
     EXPECT_TRUE(ATHandler_stub::debug_on == true);
 
-    EXPECT_TRUE(dev.open_sms(&fh1));
+    EXPECT_TRUE(dev.open_sms());
-    EXPECT_EQ(ATHandler_stub::ref_count, 1);
 
     dev.modem_debug_on(true);
     EXPECT_TRUE(ATHandler_stub::debug_on == true);
@@ -263,7 +221,6 @@ TEST_F(TestAT_CellularDevice, test_AT_CellularDevice_create_delete_context)
     AT_CellularDevice *dev = new AT_CellularDevice(&fh1);
 
     ATHandler *at = dev->get_at_handler();
-    EXPECT_TRUE(dev->release_at_handler(at) == NSAPI_ERROR_OK);
 
     CellularContext *ctx = dev->create_context(NULL);
     delete dev;
@@ -271,8 +228,8 @@ TEST_F(TestAT_CellularDevice, test_AT_CellularDevice_create_delete_context)
     dev = new AT_CellularDevice(&fh1);
     at = dev->get_at_handler();
     ctx = dev->create_context(NULL);
-    CellularContext *ctx1 = dev->create_context(&fh1);
+    CellularContext *ctx1 = dev->create_context();
-    CellularContext *ctx2 = dev->create_context(&fh1);
+    CellularContext *ctx2 = dev->create_context();
 
     EXPECT_TRUE(ctx);
     EXPECT_TRUE(ctx1);
@@ -288,9 +245,9 @@ TEST_F(TestAT_CellularDevice, test_AT_CellularDevice_create_delete_context)
     dev->delete_context(ctx2);
 
     ctx = dev->create_context(NULL);
-    ctx1 = dev->create_context(&fh1);
+    ctx1 = dev->create_context();
-    ctx2 = dev->create_context(&fh1);
+    ctx2 = dev->create_context();
-    EXPECT_TRUE(dev->release_at_handler(at) == NSAPI_ERROR_OK);
+
     EXPECT_TRUE(ctx);
     EXPECT_TRUE(ctx1);
     EXPECT_TRUE(ctx1 != ctx);

UNITTESTS/features/cellular/framework/device/athandler/athandlertest.cpp

@@ -86,43 +86,6 @@ TEST_F(TestATHandler, test_ATHandler_get_file_handle)
     EXPECT_EQ(&fh1, at.get_file_handle());
 }
 
-TEST_F(TestATHandler, test_ATHandler_set_file_handle)
-{
-    EventQueue que;
-    FileHandle_stub fh1, fh2;
-
-    ATHandler at(&fh1, que, 0, ",");
-
-    at.set_file_handle(&fh2);
-}
-
-TEST_F(TestATHandler, test_ATHandler_list)
-{
-    EventQueue que;
-    FileHandle_stub fh1;
-
-    ATHandler::set_at_timeout_list(1000, false);
-    ATHandler::set_debug_list(false);
-
-    ATHandler *at1 = ATHandler::get_instance(&fh1, que, 0, ",", 0, 0);
-
-    ATHandler::set_at_timeout_list(1000, false);
-    ATHandler::set_debug_list(true);
-
-    EXPECT_TRUE(ATHandler::get_instance(NULL, que, 0, ",", 0, 0) == NULL);
-
-    ATHandler *at2 = ATHandler::get_instance(&fh1, que, 0, ",", 0, 0);
-
-    ATHandler::set_at_timeout_list(2000, true);
-    ATHandler::set_debug_list(false);
-
-    EXPECT_TRUE(at1->close() == NSAPI_ERROR_OK);
-    EXPECT_TRUE(at2->close() == NSAPI_ERROR_OK);
-
-    ATHandler::set_at_timeout_list(1000, false);
-    ATHandler::set_debug_list(false);
-}
-
 TEST_F(TestATHandler, test_ATHandler_lock)
 {
     EventQueue que;

UNITTESTS/features/cellular/framework/device/cellularcontext/cellularcontexttest.cpp

@@ -165,9 +165,9 @@ public:
 
 	}
 #if (DEVICE_SERIAL && DEVICE_INTERRUPTIN) || defined(DOXYGEN_ONLY)
-    virtual void set_file_handle(BufferedSerial *serial, PinName dcd_pin = NC, bool active_high = false)
+    virtual nsapi_error_t configure_hup(PinName dcd_pin = NC, bool active_high = false)
     {
-
+        return NSAPI_ERROR_OK;
     }
 #endif
 	ControlPlane_netif *get_cp_netif()

UNITTESTS/stubs/ATHandler_stub.cpp

@@ -28,12 +28,9 @@ using namespace events;
 const int DEFAULT_AT_TIMEOUT = 1000;
 const uint8_t MAX_RESP_LENGTH = 7;
 
-mbed::ATHandler *ATHandler_stub::handler = NULL;
-
 nsapi_error_t ATHandler_stub::nsapi_error_value = 0;
 uint8_t ATHandler_stub::nsapi_error_ok_counter = 0;
 int ATHandler_stub::int_value = -1;
-int ATHandler_stub::ref_count = 0;
 int ATHandler_stub::timeout = 0;
 bool ATHandler_stub::default_timeout = 0;
 bool ATHandler_stub::debug_on = 0;
@@ -84,7 +81,6 @@ void ATHandler_stub::debug_call_count_clear()
 }
 
 ATHandler::ATHandler(FileHandle *fh, EventQueue &queue, uint32_t timeout, const char *output_delimiter, uint16_t send_delay) :
-    _nextATHandler(0),
 #if defined AT_HANDLER_MUTEX && defined MBED_CONF_RTOS_PRESENT
     _oobCv(_fileHandleMutex),
 #endif
@@ -111,41 +107,17 @@ bool ATHandler::get_debug() const
     return ATHandler_stub::debug_on;
 }
 
-void ATHandler::set_debug_list(bool debug_on)
-{
-    ATHandler_stub::debug_on = debug_on;
-}
-
 ATHandler::~ATHandler()
 {
     ATHandler_stub::urc_handlers.clear();
 }
 
-void ATHandler::inc_ref_count()
-{
-    ATHandler_stub::ref_count++;
-}
-
-void ATHandler::dec_ref_count()
-{
-    ATHandler_stub::ref_count--;
-}
-
-int ATHandler::get_ref_count()
-{
-    return ATHandler_stub::ref_count;
-}
-
 FileHandle *ATHandler::get_file_handle()
 {
     ATHandler_stub::fh_value = (FileHandle_stub *)_fileHandle;
     return _fileHandle;
 }
 
-void ATHandler::set_file_handle(FileHandle *fh)
-{
-}
-
 bool ATHandler::find_urc_handler(const char *prefix)
 {
     return ATHandler_stub::bool_value;
@@ -393,27 +365,6 @@ nsapi_error_t ATHandler::at_cmd_discard(const char *cmd, const char *cmd_chr,
     return ATHandler_stub::nsapi_error_value;
 }
 
-ATHandler *ATHandler::get_instance(FileHandle *fileHandle, events::EventQueue &queue, uint32_t timeout,
-                                   const char *delimiter, uint16_t send_delay, bool debug_on)
-{
-    ATHandler_stub::ref_count++;
-    int a = ATHandler_stub::ref_count;
-    a = 0;
-    return ATHandler_stub::handler;
-}
-
-nsapi_error_t ATHandler::close()
-{
-    ATHandler_stub::ref_count--;
-    return NSAPI_ERROR_OK;
-}
-
-void ATHandler::set_at_timeout_list(uint32_t timeout_milliseconds, bool default_timeout)
-{
-    ATHandler_stub::timeout = timeout_milliseconds;
-    ATHandler_stub::default_timeout = default_timeout;
-}
-
 void ATHandler::set_send_delay(uint16_t send_delay)
 {
 }

UNITTESTS/stubs/ATHandler_stub.h

@@ -34,11 +34,9 @@ static const int kATHandler_urc_table_max_size = 10;
 static const int kATHandler_urc_string_max_size = 16;
 
 namespace ATHandler_stub {
-extern mbed::ATHandler *handler;
 extern nsapi_error_t nsapi_error_value;
 extern uint8_t nsapi_error_ok_counter;
 extern int int_value;
-extern int ref_count;
 extern int timeout;
 extern bool default_timeout;
 extern bool debug_on;

UNITTESTS/stubs/AT_CellularContext_stub.cpp

@@ -21,7 +21,7 @@ using namespace mbed;
 
 AT_CellularContext::AT_CellularContext(ATHandler &at, CellularDevice *device, const char *apn,  bool cp_req, bool nonip_req) :
     _at(at), _is_connected(false),
-    _current_op(OP_INVALID), _fh(0), _cp_req(cp_req)
+    _current_op(OP_INVALID), _dcd_pin(NC), _active_high(false), _cp_req(cp_req)
 {
     _stack = NULL;
     _pdp_type = DEFAULT_PDP_TYPE;
@@ -51,17 +51,15 @@ AT_CellularContext::~AT_CellularContext()
 {
 }
 
-void AT_CellularContext::set_file_handle(BufferedSerial *serial, PinName dcd_pin, bool active_high)
+nsapi_error_t AT_CellularContext::configure_hup(PinName dcd_pin, bool active_high)
 {
+    return NSAPI_ERROR_OK;
 }
 
 void AT_CellularContext::enable_hup(bool enable)
 {
 }
 
-void AT_CellularContext::set_file_handle(FileHandle *fh)
-{
-}
 
 nsapi_error_t AT_CellularContext::connect()
 {
@@ -311,8 +309,3 @@ char *AT_CellularContext::get_interface_name(char *interface_name)
 {
     return NULL;
 }
-
-ATHandler &AT_CellularContext::get_at_handler()
-{
-    return _at;
-}

UNITTESTS/stubs/AT_CellularDevice_stub.cpp

@@ -33,7 +33,9 @@ bool AT_CellularDevice_stub::pin_needed = false;
 bool AT_CellularDevice_stub::supported_bool = false;
 int AT_CellularDevice_stub::max_sock_value = 1;
 
-AT_CellularDevice::AT_CellularDevice(FileHandle *fh) : CellularDevice(fh),
+AT_CellularDevice::AT_CellularDevice(FileHandle *fh) :
+    CellularDevice(),
+    _at(fh, _queue, get_property(AT_CellularDevice::PROPERTY_AT_SEND_DELAY), "\r"),
 #if MBED_CONF_CELLULAR_USE_SMS
     _sms(0),
 #endif // MBED_CONF_CELLULAR_USE_SMS
@@ -47,31 +49,12 @@ AT_CellularDevice::~AT_CellularDevice()
     close_network();
 }
 
-ATHandler *AT_CellularDevice::get_at_handler(FileHandle *fileHandle)
-{
-    return ATHandler::get_instance(fileHandle, _queue, _default_timeout, "\r", get_property(AT_CellularDevice::PROPERTY_AT_SEND_DELAY), _modem_debug_on);
-}
-
 ATHandler *AT_CellularDevice::get_at_handler()
 {
-    return get_at_handler(NULL);
+    return &_at;
 }
 
-nsapi_error_t AT_CellularDevice::release_at_handler(ATHandler *at_handler)
+CellularContext *create_context(const char *apn)
-{
-    if (at_handler) {
-        return at_handler->close();
-    } else {
-        return NSAPI_ERROR_PARAMETER;
-    }
-}
-
-CellularContext *AT_CellularDevice::create_context(BufferedSerial *serial, const char *const apn, PinName dcd_pin,
-                                                   bool active_high, bool cp_req, bool nonip_req)
-{
-}
-
-CellularContext *create_context(FileHandle *fh, const char *apn)
 {
 }
 
@@ -79,21 +62,16 @@ void delete_context(CellularContext *context)
 {
 }
 
-CellularNetwork *AT_CellularDevice::open_network(FileHandle *fh)
+CellularNetwork *AT_CellularDevice::open_network()
 {
     if (_network) {
         return _network;
     }
-    _network = new AT_CellularNetwork(*ATHandler::get_instance(fh,
+    _network = new AT_CellularNetwork(_at, *this);
-                                                               _queue,
-                                                               _default_timeout,
-                                                               "\r",
-                                                               get_property(AT_CellularDevice::PROPERTY_AT_SEND_DELAY),
-                                                               _modem_debug_on), *this);
     return _network;
 }
 #if MBED_CONF_CELLULAR_USE_SMS
-CellularSMS *AT_CellularDevice::open_sms(FileHandle *fh)
+CellularSMS *AT_CellularDevice::open_sms()
 {
     return NULL;
 }
@@ -109,7 +87,7 @@ AT_CellularSMS *AT_CellularDevice::open_sms_impl(ATHandler &at)
 
 #endif // MBED_CONF_CELLULAR_USE_SMS
 
-CellularInformation *AT_CellularDevice::open_information(FileHandle *fh)
+CellularInformation *AT_CellularDevice::open_information()
 {
     return NULL;
 }
@@ -117,10 +95,8 @@ CellularInformation *AT_CellularDevice::open_information(FileHandle *fh)
 void AT_CellularDevice::close_network()
 {
     if (_network) {
-        ATHandler *atHandler = &_network->get_at_handler();
         delete _network;
         _network = NULL;
-        release_at_handler(atHandler);
     }
 }
 
@@ -133,7 +109,7 @@ CellularContext *AT_CellularDevice::get_context_list() const
     return NULL;
 }
 
-CellularContext *AT_CellularDevice::create_context(FileHandle *fh, const char *apn, bool cp_req, bool nonip_req)
+CellularContext *AT_CellularDevice::create_context(const char *apn, bool cp_req, bool nonip_req)
 {
     return NULL;
 }

UNITTESTS/stubs/AT_CellularInformation_stub.cpp

@@ -57,8 +57,3 @@ nsapi_error_t AT_CellularInformation::get_iccid(char *buf, size_t buf_size)
 {
     return NSAPI_ERROR_OK;
 }
-
-ATHandler &AT_CellularInformation::get_at_handler()
-{
-    return _at;
-}

UNITTESTS/stubs/AT_CellularNetwork_stub.cpp

@@ -171,8 +171,3 @@ nsapi_error_t AT_CellularNetwork::clear()
 {
     return NSAPI_ERROR_OK;
 }
-
-ATHandler &AT_CellularNetwork::get_at_handler()
-{
-    return _at;
-}

UNITTESTS/stubs/AT_CellularSMS_stub.cpp

@@ -188,9 +188,3 @@ bool AT_CellularSMS::create_time(const char *time_string, time_t *time)
 {
     return 0;
 }
-
-ATHandler &AT_CellularSMS::get_at_handler()
-{
-    return _at;
-}
-

UNITTESTS/stubs/CellularContext_stub.cpp

@@ -22,7 +22,7 @@ namespace mbed {
 CellularContext::CellularContext() : _next(0), _stack(0), _pdp_type(DEFAULT_PDP_TYPE),
     _authentication_type(CellularContext::CHAP), _connect_status(NSAPI_STATUS_DISCONNECTED), _status_cb(0),
     _cid(-1), _new_context_set(false), _is_context_active(false), _is_context_activated(false),
-    _apn(0), _uname(0), _pwd(0), _dcd_pin(NC), _active_high(false), _cp_netif(0), _retry_array_length(0),
+    _apn(0), _uname(0), _pwd(0), _cp_netif(0), _retry_array_length(0),
     _retry_count(0), _device(0), _nw(0), _is_blocking(true)
 {
     memset(_retry_timeout_array, 0, CELLULAR_RETRY_ARRAY_SIZE);

UNITTESTS/stubs/CellularDevice_stub.cpp

@@ -37,11 +37,12 @@ MBED_WEAK CellularDevice *CellularDevice::get_default_instance()
     }
 }
 
-CellularDevice::CellularDevice(FileHandle *fh) : _network_ref_count(0),
+CellularDevice::CellularDevice() :
+    _network_ref_count(0),
 #if MBED_CONF_CELLULAR_USE_SMS
     _sms_ref_count(0),
 #endif //MBED_CONF_CELLULAR_USE_SMS
-    _info_ref_count(0), _fh(fh), _queue(10 * EVENTS_EVENT_SIZE), _state_machine(0),
+    _info_ref_count(0), _queue(10 * EVENTS_EVENT_SIZE), _state_machine(0),
     _nw(0), _status_cb(0)
 {
 }

UNITTESTS/target_h/myCellularContext.h

@@ -39,18 +39,15 @@ public:
         }
     }
 
-    void set_file_handle(BufferedSerial *serial, PinName dcd_pin, bool active_high)
+    nsapi_error_t configure_hup(PinName dcd_pin, bool active_high)
     {
+        return NSAPI_ERROR_OK;
     };
 
     void enable_hup(bool enable)
     {
     };
 
-    void set_file_handle(FileHandle *fh)
-    {
-    };
-
     nsapi_error_t connect()
     {
         return NSAPI_ERROR_OK;

UNITTESTS/target_h/myCellularDevice.h

@@ -53,19 +53,8 @@ public:
         return NSAPI_ERROR_OK;
     }
 
-    virtual CellularContext *create_context(BufferedSerial *serial, const char *const apn, PinName dcd_pin,
-                                            bool active_high, bool cp_req = false, bool nonip_req = false)
-    {
-        if (_context_list) {
-            return _context_list;
-        }
-        EventQueue que;
-        ATHandler at(serial, que, 0, ",");
-        _context_list = new AT_CellularContext(at, this);
-        return _context_list;
-    }
 
-    virtual CellularContext *create_context(FileHandle *fh = NULL, const char *apn = NULL, bool cp_req = false, bool nonip_req = false)
+    virtual CellularContext *create_context(const char *apn = NULL, bool cp_req = false, bool nonip_req = false)
     {
         if (_context_list) {
             return _context_list;
@@ -82,7 +71,7 @@ public:
         delete _context_list;
     }
 
-    virtual CellularNetwork *open_network(FileHandle *fh = NULL)
+    virtual CellularNetwork *open_network()
     {
         if (_network) {
             return _network;
@@ -94,12 +83,12 @@ public:
         return _network;
     }
 
-    virtual CellularSMS *open_sms(FileHandle *fh = NULL)
+    virtual CellularSMS *open_sms()
     {
         return NULL;
     }
 
-    virtual CellularInformation *open_information(FileHandle *fh = NULL)
+    virtual CellularInformation *open_information()
     {
         return NULL;
     }

components/cellular/COMPONENT_STMOD_CELLULAR/STModCellular.cpp

@@ -88,23 +88,23 @@ nsapi_error_t STModCellular::soft_power_on()
     }
 
     // wait for RDY
-    _at->lock();
+    _at.lock();
-    _at->set_at_timeout(5000);
+    _at.set_at_timeout(5000);
-    _at->set_stop_tag("RDY");
+    _at.set_stop_tag("RDY");
-    bool rdy = _at->consume_to_stop_tag();
+    bool rdy = _at.consume_to_stop_tag();
     (void)rdy;
 
     /*  Modem may send more bytes are RDY flag */
-    _at->flush();
+    _at.flush();
 
     /* Turn OFF ECHO before anything else */
-    _at->set_stop_tag(mbed::OK);
+    _at.set_stop_tag(mbed::OK);
-    _at->cmd_start("ATE0");
+    _at.cmd_start("ATE0");
-    _at->cmd_stop();
+    _at.cmd_stop();
-    _at->consume_to_stop_tag();
+    _at.consume_to_stop_tag();
 
-    _at->restore_at_timeout();
+    _at.restore_at_timeout();
-    _at->unlock();
+    _at.unlock();
 
     tr_info("Modem %sready to receive AT commands", rdy ? "" : "NOT ");
 
@@ -113,17 +113,17 @@ nsapi_error_t STModCellular::soft_power_on()
 
         pin_mode(MBED_CONF_STMOD_CELLULAR_CTS, PullDown);
 
-        _at->lock();
+        _at.lock();
         // enable CTS/RTS flowcontrol
-        _at->set_stop_tag(mbed::OK);
+        _at.set_stop_tag(mbed::OK);
-        _at->set_at_timeout(400);
+        _at.set_at_timeout(400);
-        _at->cmd_start("AT+IFC=");
+        _at.cmd_start("AT+IFC=");
-        _at->write_int(2);
+        _at.write_int(2);
-        _at->write_int(2);
+        _at.write_int(2);
-        _at->cmd_stop_read_resp();
+        _at.cmd_stop_read_resp();
-        err = _at->get_last_error();
+        err = _at.get_last_error();
-        _at->restore_at_timeout();
+        _at.restore_at_timeout();
-        _at->unlock();
+        _at.unlock();
 
         if (err == NSAPI_ERROR_OK) {
             tr_debug("Flow control turned ON");
@@ -135,11 +135,11 @@ nsapi_error_t STModCellular::soft_power_on()
     rtos::ThisThread::sleep_for(500);
 
 #if MBED_CONF_CELLULAR_DEBUG_AT
-    _at->lock();
+    _at.lock();
     /*  Verify Flow Control settings */
-    _at->cmd_start("AT+IFC?");
+    _at.cmd_start("AT+IFC?");
-    _at->cmd_stop_read_resp();
+    _at.cmd_stop_read_resp();
-    _at->unlock();
+    _at.unlock();
 #endif // MBED_CONF_CELLULAR_DEBUG_AT
 
     return err;
@@ -147,8 +147,8 @@ nsapi_error_t STModCellular::soft_power_on()
 
 nsapi_error_t STModCellular::soft_power_off()
 {
-    _at->cmd_start("AT+QPOWD");
+    _at.cmd_start("AT+QPOWD");
-    _at->cmd_stop();
+    _at.cmd_stop();
     rtos::ThisThread::sleep_for(1000);
     // should wait for POWERED DOWN with a time out up to 65 second according to the manual.
     // we cannot afford such a long wait though.

features/cellular/framework/API/ATHandler.h

@@ -86,32 +86,6 @@ public:
      */
     FileHandle *get_file_handle();
 
-    /** Get a new ATHandler instance, and update the linked list. Once the use of the ATHandler
-     *  has finished, call to close() has to be made
-     *
-     *  @param fileHandle       filehandle used for reading AT responses and writing AT commands.
-     *                          If there is already an ATHandler with the same fileHandle pointer,
-     *                          then a pointer to that ATHandler instance will be returned with
-     *                          that ATHandler's queue, timeout, delimiter, send_delay and debug_on
-     *                          values
-     *  @param queue            Event queue used to transfer sigio events to this thread
-     *  @param timeout          Timeout when reading for AT response
-     *  @param delimiter        delimiter used when parsing at responses, "\r" should be used as output_delimiter
-     *  @param send_delay       the minimum delay in ms between the end of last response and the beginning of a new command
-     *  @param debug_on         Set true to enable debug traces
-     *  @return                 NULL, if fileHandle is not set, or a pointer to an existing ATHandler, if the fileHandle is
-     *                          already in use. Otherwise a pointer to a new ATHandler instance is returned
-     */
-    static ATHandler *get_instance(FileHandle *fileHandle, events::EventQueue &queue, uint32_t timeout,
-                                   const char *delimiter, uint16_t send_delay, bool debug_on);
-
-    /** Close and delete the current ATHandler instance, if the reference count to it is 0.
-     *  Close() can be only called, if the ATHandler was opened with get_instance()
-     *
-     *  @return NSAPI_ERROR_OK on success, NSAPI_ERROR_PARAMETER on failure
-     */
-    nsapi_error_t close();
-
     /** Locks the mutex for file handle if AT_HANDLER_MUTEX is defined.
      */
     void lock();
@@ -133,8 +107,6 @@ public:
      */
     void set_urc_handler(const char *prefix, Callback<void()> callback);
 
-    ATHandler *_nextATHandler; // linked list
-
     /** returns the last error while parsing AT responses.
      *
      *  @return last error
@@ -154,13 +126,6 @@ public:
      */
     void set_at_timeout(uint32_t timeout_milliseconds, bool default_timeout = false);
 
-    /** Set timeout in milliseconds for all ATHandlers in the _atHandlers list
-     *
-     *  @param timeout_milliseconds  Timeout in milliseconds
-     *  @param default_timeout       Store as default timeout
-     */
-    static void set_at_timeout_list(uint32_t timeout_milliseconds, bool default_timeout = false);
-
     /** Restore timeout to previous timeout. Handy if there is a need to change timeout temporarily.
      */
     void restore_at_timeout();
@@ -178,12 +143,6 @@ public:
      */
     void process_oob();
 
-    /** Set file handle, which is used for reading AT responses and writing AT commands
-     *
-     *  @param fh file handle used for reading AT responses and writing AT commands
-     */
-    void set_file_handle(FileHandle *fh);
-
     /** Set is file handle usable. Some situations like after going to data mode, file handle is not usable anymore.
      *  Any items in queue are not to be processed.
      *
@@ -448,12 +407,6 @@ public: // just for debugging
      */
     bool get_debug() const;
 
-    /** Set debug_on for all ATHandlers in the _atHandlers list
-     *
-     *  @param debug_on Set true to enable debug traces
-     */
-    static void set_debug_list(bool debug_on);
-
 private: //Private structs & enums
     struct tag_t {
         char tag[7];
@@ -621,8 +574,6 @@ private: //Member variables
     int32_t _ref_count;
     bool _is_fh_usable;
 
-    static ATHandler *_atHandlers;
-
     // should fit any prefix and int
     char _recv_buff[BUFF_SIZE];
     // reading position

features/cellular/framework/API/CellularContext.h

@@ -261,21 +261,23 @@ public: // from NetworkInterface
      */
     virtual nsapi_error_t get_apn_backoff_timer(int &backoff_timer) = 0;
 
-    /** Set the file handle used to communicate with the modem. You can use this to change the default file handle.
-     *
-     *  @param fh   file handle for communicating with the modem
-     */
-    virtual void set_file_handle(FileHandle *fh) = 0;
-
 #if (DEVICE_SERIAL && DEVICE_INTERRUPTIN) || defined(DOXYGEN_ONLY)
-    /** Set the UART serial used to communicate with the modem. Can be used to change default file handle.
+
-     *  File handle set with this method will use data carrier detect to be able to detect disconnection much faster in PPP mode.
+    /** Enable or disable hang-up detection.
      *
-     *  @param serial       BufferedSerial used in communication to modem. If null then the default file handle is used.
+     *  This method will use data carrier detect to be able to detect disconnection much faster in PPP mode.
-     *  @param dcd_pin      Pin used to set data carrier detect on/off for the given UART
+     *
+     *  When in PPP data pump mode, it is helpful if the FileHandle will signal hang-up via
+     *  POLLHUP, e.g., if the DCD line is deasserted on a UART. During command mode, this
+     *  signaling is not desired.
+     *
+     *  @param dcd_pin      Pin used to set data carrier detect on/off for the given UART. NC if feature is disabled.
      *  @param active_high  a boolean set to true if DCD polarity is active low
+     *
+     *  @return             NSAPI_ERROR_OK if success,
+     *                      NSAPI_ERROR_UNSUPPORTED if modem does not support this feature
      */
-    virtual void set_file_handle(BufferedSerial *serial, PinName dcd_pin = NC, bool active_high = false) = 0;
+    virtual nsapi_error_t configure_hup(PinName dcd_pin = NC, bool active_high = false) = 0;
 #endif // #if DEVICE_SERIAL
 
     /** Returns the control plane AT command interface
@@ -320,15 +322,6 @@ protected: // Device specific implementations might need these so protected
     */
     virtual void cellular_callback(nsapi_event_t ev, intptr_t ptr) = 0;
 
-    /** Enable or disable hang-up detection
-     *
-     *  When in PPP data pump mode, it is helpful if the FileHandle will signal hang-up via
-     *  POLLHUP, e.g., if the DCD line is deasserted on a UART. During command mode, this
-     *  signaling is not desired. enable_hup() controls whether this function should be
-     *  active.
-     */
-    virtual void enable_hup(bool enable) = 0;
-
     /** Return PDP type string for Non-IP if modem uses other than standard "Non-IP"
      *
      *  Some modems uses a non-standard PDP type string for non-ip (e.g. "NONIP").
@@ -387,8 +380,6 @@ protected:
     const char *_apn;
     const char *_uname;
     const char *_pwd;
-    PinName _dcd_pin;
-    bool _active_high;
 
     ControlPlane_netif *_cp_netif;
     uint16_t _retry_timeout_array[CELLULAR_RETRY_ARRAY_SIZE];

features/cellular/framework/API/CellularDevice.h

@@ -21,10 +21,7 @@
 #include "CellularStateMachine.h"
 #include "Callback.h"
 #include "ATHandler.h"
-
+#include "PinNames.h"
-#if (DEVICE_SERIAL && DEVICE_INTERRUPTIN) || defined(DOXYGEN_ONLY)
-#include "drivers/BufferedSerial.h"
-#endif // #if DEVICE_SERIAL
 
 #ifdef MBED_CONF_RTOS_PRESENT
 #include "Thread.h"
@@ -40,7 +37,6 @@ class CellularSMS;
 class CellularInformation;
 class CellularNetwork;
 class CellularContext;
-class FileHandle;
 
 const int MAX_PIN_SIZE = 8;
 const int MAX_PLMN_SIZE = 16;
@@ -86,10 +82,8 @@ public:
     static CellularDevice *get_target_default_instance();
 
     /** Default constructor
-     *
-     *  @param fh   File handle used in communication with the modem.
      */
-    CellularDevice(FileHandle *fh);
+    CellularDevice();
 
     /** virtual Destructor
      */
@@ -232,26 +226,7 @@ public: //Pure virtual functions
      *  @return         new instance of class CellularContext or NULL in case of failure
      *
      */
-    virtual CellularContext *create_context(FileHandle *fh = NULL, const char *apn = NULL, bool cp_req = false, bool nonip_req = false) = 0;
+    virtual CellularContext *create_context(const char *apn = NULL, bool cp_req = false, bool nonip_req = false) = 0;
-
-#if (DEVICE_SERIAL && DEVICE_INTERRUPTIN) || defined(DOXYGEN_ONLY)
-    /** Creates a new CellularContext interface. This API should be used if serial is UART and PPP mode used.
-     *  CellularContext created will use data carrier detect to be able to detect disconnection much faster in PPP mode.
-     *  BufferedSerial usually is the same which was given for the CellularDevice.
-     *
-     *  @param serial       BufferedSerial used in communication to modem. If null then the default file handle is used.
-     *  @param apn          access point to use with context, can be null.
-     *  @param dcd_pin      Pin used to set data carrier detect on/off for the given UART
-     *  @param active_high  a boolean set to true if DCD polarity is active low
-     *  @param cp_req       Flag indicating if EPS control plane optimization is required
-     *  @param nonip_req    Flag indicating if this context is required to be Non-IP
-     *
-     *  @return         new instance of class CellularContext or NULL in case of failure
-     *
-     */
-    virtual CellularContext *create_context(BufferedSerial *serial, const char *apn, PinName dcd_pin = NC,
-                                            bool active_high = false, bool cp_req = false, bool nonip_req = false) = 0;
-#endif // #if DEVICE_SERIAL
 
     /** Deletes the given CellularContext instance
      *
@@ -307,19 +282,11 @@ public: //Pure virtual functions
     virtual nsapi_error_t set_power_save_mode(int periodic_time, int active_time = 0) = 0;
 
     /** Get the current ATHandler instance in use for debug purposes etc.
-     *  Once use has been finished call to release_at_handler() has to be made
      *
-     *  @return Pointer to the ATHandler in use
+     *  @return Pointer to the ATHandler in use, NULL if device is non-AT -device.
      */
     virtual ATHandler *get_at_handler() = 0;
 
-    /** Release the ATHandler taken into use with get_at_handler()
-     *
-     *  @param at_handler
-     *  @return NSAPI_ERROR_OK on success, NSAPI_ERROR_PARAMETER on failure
-     */
-    virtual nsapi_error_t release_at_handler(ATHandler *at_handler) = 0;
-
     /** Sets cellular modem to given baud rate
      *
      *  @param baud_rate
@@ -333,7 +300,7 @@ public: //Pure virtual functions
      *               file handle is used.
      *  @return      New instance of interface CellularNetwork.
      */
-    virtual CellularNetwork *open_network(FileHandle *fh = NULL) = 0;
+    virtual CellularNetwork *open_network() = 0;
 
 #if MBED_CONF_CELLULAR_USE_SMS || defined(DOXYGEN_ONLY)
     /** Create new CellularSMS interface.
@@ -342,7 +309,7 @@ public: //Pure virtual functions
      *               file handle is used.
      *  @return      New instance of interface CellularSMS.
      */
-    virtual CellularSMS *open_sms(FileHandle *fh = NULL) = 0;
+    virtual CellularSMS *open_sms() = 0;
 
     /** Closes the opened CellularSMS by deleting the CellularSMS instance.
      */
@@ -356,7 +323,7 @@ public: //Pure virtual functions
      *               file handle is used.
      *  @return      New instance of interface CellularInformation.
      */
-    virtual CellularInformation *open_information(FileHandle *fh = NULL) = 0;
+    virtual CellularInformation *open_information() = 0;
 
     /** Closes the opened CellularNetwork by deleting the CellularNetwork instance.
      */
@@ -377,11 +344,6 @@ public: //Pure virtual functions
 
 public: //Common functions
 
-    /** Get the current FileHandle item used when communicating with the modem.
-     *
-     *  @return reference to FileHandle
-     */
-    FileHandle &get_file_handle() const;
 
     /** Set the pin code for SIM card
      *
@@ -493,7 +455,6 @@ protected: //Member variables
     int _sms_ref_count;
 #endif // MBED_CONF_CELLULAR_USE_SMS
     int _info_ref_count;
-    FileHandle *_fh;
     events::EventQueue _queue;
     CellularStateMachine *_state_machine;
     Callback<void(nsapi_event_t, intptr_t)> _status_cb;

features/cellular/framework/AT/AT_CellularContext.cpp

@@ -47,7 +47,7 @@ using namespace mbed;
 using namespace rtos;
 
 AT_CellularContext::AT_CellularContext(ATHandler &at, CellularDevice *device, const char *apn, bool cp_req, bool nonip_req) :
-    _current_op(OP_INVALID), _fh(0), _cp_req(cp_req), _is_connected(false), _at(at)
+    _current_op(OP_INVALID), _dcd_pin(NC), _active_high(false), _cp_req(cp_req), _is_connected(false), _at(at)
 {
     tr_info("New CellularContext %s (%p)", apn ? apn : "", this);
     _nonip_req = nonip_req;
@@ -71,22 +71,13 @@ AT_CellularContext::~AT_CellularContext()
     }
 }
 
-void AT_CellularContext::set_file_handle(FileHandle *fh)
-{
-    tr_info("CellularContext filehandle %p", fh);
-    _fh = fh;
-    _at.set_file_handle(_fh);
-}
-
 #if (DEVICE_SERIAL && DEVICE_INTERRUPTIN) || defined(DOXYGEN_ONLY)
-void AT_CellularContext::set_file_handle(BufferedSerial *serial, PinName dcd_pin, bool active_high)
+nsapi_error_t AT_CellularContext::configure_hup(PinName dcd_pin, bool active_high)
 {
-    tr_info("CellularContext serial %p", serial);
     _dcd_pin = dcd_pin;
     _active_high = active_high;
-    _fh = serial;
-    _at.set_file_handle(static_cast<FileHandle *>(serial));
     enable_hup(false);
+    return NSAPI_ERROR_OK;
 }
 #endif // #if DEVICE_SERIAL
 
@@ -94,7 +85,7 @@ void AT_CellularContext::enable_hup(bool enable)
 {
     if (_dcd_pin != NC) {
 #if (DEVICE_SERIAL && DEVICE_INTERRUPTIN) || defined(DOXYGEN_ONLY)
-        static_cast<BufferedSerial *>(_fh)->set_data_carrier_detect(enable ? _dcd_pin : NC, _active_high);
+        static_cast<BufferedSerial *>(_at.get_file_handle())->set_data_carrier_detect(enable ? _dcd_pin : NC, _active_high);
 #endif // #if DEVICE_SERIAL
     }
 }
@@ -967,7 +958,7 @@ void AT_CellularContext::cellular_callback(nsapi_event_t ev, intptr_t ptr)
 #endif // MBED_CONF_CELLULAR_USE_APN_LOOKUP
 
         if (!_nw && st == CellularDeviceReady && _cb_data.error == NSAPI_ERROR_OK) {
-            _nw = _device->open_network(_fh);
+            _nw = _device->open_network();
         }
 
 #if MBED_CONF_CELLULAR_CONTROL_PLANE_OPT
@@ -1113,8 +1104,3 @@ void AT_CellularContext::set_cid(int cid)
         static_cast<AT_CellularStack *>(_stack)->set_cid(_cid);
     }
 }
-
-ATHandler &AT_CellularContext::get_at_handler()
-{
-    return _at;
-}

features/cellular/framework/AT/AT_CellularContext.h

@@ -62,19 +62,17 @@ public:
     virtual nsapi_error_t set_sim_ready();
     virtual nsapi_error_t register_to_network();
     virtual nsapi_error_t attach_to_network();
-    virtual void set_file_handle(FileHandle *fh);
 #if (DEVICE_SERIAL && DEVICE_INTERRUPTIN) || defined(DOXYGEN_ONLY)
-    virtual void set_file_handle(BufferedSerial *serial, PinName dcd_pin = NC, bool active_high = false);
+    virtual nsapi_error_t configure_hup(PinName dcd_pin = NC, bool active_high = false);
 #endif // #if DEVICE_SERIAL
-    virtual void enable_hup(bool enable);
 
     virtual ControlPlane_netif *get_cp_netif();
 
     AT_CellularDevice *get_device() const;
 
-    ATHandler &get_at_handler();
-
 protected:
+    virtual void enable_hup(bool enable);
+
     virtual void cellular_callback(nsapi_event_t ev, intptr_t ptr);
 
     /** Does the authentication for the PDP Context if user name and password are provided.
@@ -132,11 +130,13 @@ private:
     void set_cid(int cid);
 
 private:
-    ContextOperation  _current_op;
+    ContextOperation _current_op;
-    FileHandle *_fh;
     rtos::Semaphore _semaphore;
     rtos::Semaphore _cp_opt_semaphore;
 
+    PinName _dcd_pin;
+    bool _active_high;
+
 protected:
     char _found_apn[MAX_APN_LENGTH];
     // flag indicating if CP was requested to be setup

features/cellular/framework/AT/AT_CellularDevice.cpp

@@ -38,25 +38,29 @@ using namespace mbed;
 #define DEFAULT_AT_TIMEOUT 1000 // at default timeout in milliseconds
 const int MAX_SIM_RESPONSE_LENGTH = 16;
 
-AT_CellularDevice::AT_CellularDevice(FileHandle *fh) : CellularDevice(fh),
+AT_CellularDevice::AT_CellularDevice(FileHandle *fh) :
+    CellularDevice(),
+    _at(fh, _queue, DEFAULT_AT_TIMEOUT, "\r"),
 #if MBED_CONF_CELLULAR_USE_SMS
     _sms(0),
 #endif // MBED_CONF_CELLULAR_USE_SMS
-    _network(0), _information(0), _context_list(0), _default_timeout(DEFAULT_AT_TIMEOUT),
+    _network(0),
-    _modem_debug_on(false), _property_array(NULL)
+    _information(0),
+    _context_list(0),
+    _default_timeout(DEFAULT_AT_TIMEOUT),
+    _modem_debug_on(false),
+    _property_array(NULL)
 {
     MBED_ASSERT(fh);
-    _at = get_at_handler(fh);
-    MBED_ASSERT(_at);
 }
 
 AT_CellularDevice::~AT_CellularDevice()
 {
     if (get_property(PROPERTY_AT_CGEREP)) {
-        _at->set_urc_handler("+CGEV: NW DEACT", nullptr);
+        _at.set_urc_handler("+CGEV: NW DEACT", nullptr);
-        _at->set_urc_handler("+CGEV: ME DEACT", nullptr);
+        _at.set_urc_handler("+CGEV: ME DEACT", nullptr);
-        _at->set_urc_handler("+CGEV: NW PDN D", nullptr);
+        _at.set_urc_handler("+CGEV: NW PDN D", nullptr);
-        _at->set_urc_handler("+CGEV: ME PDN D", nullptr);
+        _at.set_urc_handler("+CGEV: ME PDN D", nullptr);
     }
 
     // make sure that all is deleted even if somewhere close was not called and reference counting is messed up.
@@ -78,13 +82,9 @@ AT_CellularDevice::~AT_CellularDevice()
     AT_CellularContext *next;
     while (curr) {
         next = (AT_CellularContext *)curr->_next;
-        ATHandler *at = &curr->get_at_handler();
         delete curr;
         curr = next;
-        release_at_handler(at);
     }
-
-    release_at_handler(_at);
 }
 
 void AT_CellularDevice::set_at_urcs_impl()
@@ -94,10 +94,10 @@ void AT_CellularDevice::set_at_urcs_impl()
 void AT_CellularDevice::set_at_urcs()
 {
     if (get_property(PROPERTY_AT_CGEREP)) {
-        _at->set_urc_handler("+CGEV: NW DEACT", callback(this, &AT_CellularDevice::urc_nw_deact));
+        _at.set_urc_handler("+CGEV: NW DEACT", callback(this, &AT_CellularDevice::urc_nw_deact));
-        _at->set_urc_handler("+CGEV: ME DEACT", callback(this, &AT_CellularDevice::urc_nw_deact));
+        _at.set_urc_handler("+CGEV: ME DEACT", callback(this, &AT_CellularDevice::urc_nw_deact));
-        _at->set_urc_handler("+CGEV: NW PDN D", callback(this, &AT_CellularDevice::urc_pdn_deact));
+        _at.set_urc_handler("+CGEV: NW PDN D", callback(this, &AT_CellularDevice::urc_pdn_deact));
-        _at->set_urc_handler("+CGEV: ME PDN D", callback(this, &AT_CellularDevice::urc_pdn_deact));
+        _at.set_urc_handler("+CGEV: ME PDN D", callback(this, &AT_CellularDevice::urc_pdn_deact));
     }
 
     set_at_urcs_impl();
@@ -107,24 +107,24 @@ void AT_CellularDevice::setup_at_handler()
 {
     set_at_urcs();
 
-    _at->set_send_delay(get_property(AT_CellularDevice::PROPERTY_AT_SEND_DELAY));
+    _at.set_send_delay(get_property(AT_CellularDevice::PROPERTY_AT_SEND_DELAY));
 }
 
 void AT_CellularDevice::urc_nw_deact()
 {
     // The network has forced a context deactivation
     char buf[10];
-    _at->read_string(buf, 10);
+    _at.read_string(buf, 10);
     int cid;
     if (isalpha(buf[0])) {
         // this is +CGEV: NW DEACT <PDP_type>, <PDP_addr>, [<cid>]
         // or      +CGEV: ME DEACT <PDP_type>, <PDP_addr>, [<cid>]
-        _at->skip_param(); // skip <PDP_addr>
+        _at.skip_param(); // skip <PDP_addr>
-        cid = _at->read_int();
+        cid = _at.read_int();
     } else {
         // this is +CGEV: NW DEACT <p_cid>, <cid>, <event_type>[,<WLAN_Offload>]
         // or      +CGEV: ME DEACT <p_cid>, <cid>, <event_type
-        cid = _at->read_int();
+        cid = _at.read_int();
     }
     send_disconnect_to_context(cid);
 }
@@ -135,11 +135,11 @@ void AT_CellularDevice::urc_pdn_deact()
     // The mobile termination has deactivated a context.
     // +CGEV: NW PDN DEACT <cid>[,<WLAN_Offload>]
     // +CGEV: ME PDN DEACT <cid>
-    _at->set_delimiter(' ');
+    _at.set_delimiter(' ');
-    _at->skip_param();
+    _at.skip_param();
-    _at->set_delimiter(',');
+    _at.set_delimiter(',');
 
-    int cid = _at->read_int();
+    int cid = _at.read_int();
     send_disconnect_to_context(cid);
 }
 
@@ -180,42 +180,22 @@ nsapi_error_t AT_CellularDevice::soft_power_off()
     return NSAPI_ERROR_OK;
 }
 
-// each parser is associated with one filehandle (that is UART)
-ATHandler *AT_CellularDevice::get_at_handler(FileHandle *fileHandle)
-{
-    if (!fileHandle) {
-        fileHandle = _fh;
-    }
-
-    return ATHandler::get_instance(fileHandle, _queue, _default_timeout,
-                                   "\r", get_property(AT_CellularDevice::PROPERTY_AT_SEND_DELAY), _modem_debug_on);
-}
-
 ATHandler *AT_CellularDevice::get_at_handler()
 {
-    return get_at_handler(NULL);
+    return &_at;
-}
-
-nsapi_error_t AT_CellularDevice::release_at_handler(ATHandler *at_handler)
-{
-    if (at_handler) {
-        return at_handler->close();
-    } else {
-        return NSAPI_ERROR_PARAMETER;
-    }
 }
 
 nsapi_error_t AT_CellularDevice::get_sim_state(SimState &state)
 {
     char simstr[MAX_SIM_RESPONSE_LENGTH];
-    _at->lock();
+    _at.lock();
-    _at->flush();
+    _at.flush();
-    nsapi_error_t error = _at->at_cmd_str("+CPIN", "?", simstr, sizeof(simstr));
+    nsapi_error_t error = _at.at_cmd_str("+CPIN", "?", simstr, sizeof(simstr));
     ssize_t len = strlen(simstr);
 #if MBED_CONF_MBED_TRACE_ENABLE
-    device_err_t err = _at->get_last_device_error();
+    device_err_t err = _at.get_last_device_error();
 #endif
-    _at->unlock();
+    _at.unlock();
 
     if (len != -1) {
         if (len >= 5 && memcmp(simstr, "READY", 5) == 0) {
@@ -268,16 +248,16 @@ nsapi_error_t AT_CellularDevice::set_pin(const char *sim_pin)
         return NSAPI_ERROR_PARAMETER;
     }
 
-    _at->lock();
+    _at.lock();
 
-    const bool stored_debug_state = _at->get_debug();
+    const bool stored_debug_state = _at.get_debug();
-    _at->set_debug(false);
+    _at.set_debug(false);
 
-    _at->at_cmd_discard("+CPIN", "=", "%s", sim_pin);
+    _at.at_cmd_discard("+CPIN", "=", "%s", sim_pin);
 
-    _at->set_debug(stored_debug_state);
+    _at.set_debug(stored_debug_state);
 
-    return _at->unlock_return_error();
+    return _at.unlock_return_error();
 }
 
 CellularContext *AT_CellularDevice::get_context_list() const
@@ -285,22 +265,9 @@ CellularContext *AT_CellularDevice::get_context_list() const
     return _context_list;
 }
 
-#if (DEVICE_SERIAL && DEVICE_INTERRUPTIN) || defined(DOXYGEN_ONLY)
+CellularContext *AT_CellularDevice::create_context(const char *apn, bool cp_req, bool nonip_req)
-CellularContext *AT_CellularDevice::create_context(BufferedSerial *serial, const char *const apn, PinName dcd_pin,
-                                                   bool active_high, bool cp_req, bool nonip_req)
 {
-    // Call FileHandle base version - explict upcast to avoid recursing into ourselves
+    AT_CellularContext *ctx = create_context_impl(_at, apn, cp_req, nonip_req);
-    CellularContext *ctx = create_context(static_cast<FileHandle *>(serial), apn, cp_req, nonip_req);
-    if (serial) {
-        ctx->set_file_handle(serial, dcd_pin, active_high);
-    }
-    return ctx;
-}
-#endif // #if DEVICE_SERIAL
-
-CellularContext *AT_CellularDevice::create_context(FileHandle *fh, const char *apn, bool cp_req, bool nonip_req)
-{
-    AT_CellularContext *ctx = create_context_impl(*get_at_handler(fh), apn, cp_req, nonip_req);
     AT_CellularContext *curr = _context_list;
 
     if (_context_list == NULL) {
@@ -320,9 +287,6 @@ CellularContext *AT_CellularDevice::create_context(FileHandle *fh, const char *a
 
 AT_CellularContext *AT_CellularDevice::create_context_impl(ATHandler &at, const char *apn, bool cp_req, bool nonip_req)
 {
-    if (cp_req) {
-
-    }
     return new AT_CellularContext(at, this, apn, cp_req, nonip_req);
 }
 
@@ -341,28 +305,22 @@ void AT_CellularDevice::delete_context(CellularContext *context)
         prev = curr;
         curr = (AT_CellularContext *)curr->_next;
     }
-    curr = (AT_CellularContext *)context;
-    ATHandler *at = NULL;
-    if (curr) {
-        at = &curr->get_at_handler();
-    }
     delete (AT_CellularContext *)context;
-    release_at_handler(at);
 }
 
-CellularNetwork *AT_CellularDevice::open_network(FileHandle *fh)
+CellularNetwork *AT_CellularDevice::open_network()
 {
     if (!_network) {
-        _network = open_network_impl(*get_at_handler(fh));
+        _network = open_network_impl(*get_at_handler());
     }
     _network_ref_count++;
     return _network;
 }
 
-CellularInformation *AT_CellularDevice::open_information(FileHandle *fh)
+CellularInformation *AT_CellularDevice::open_information()
 {
     if (!_information) {
-        _information = open_information_impl(*get_at_handler(fh));
+        _information = open_information_impl(*get_at_handler());
     }
     _info_ref_count++;
     return _information;
@@ -375,10 +333,10 @@ AT_CellularNetwork *AT_CellularDevice::open_network_impl(ATHandler &at)
 
 #if MBED_CONF_CELLULAR_USE_SMS
 
-CellularSMS *AT_CellularDevice::open_sms(FileHandle *fh)
+CellularSMS *AT_CellularDevice::open_sms()
 {
     if (!_sms) {
-        _sms = open_sms_impl(*get_at_handler(fh));
+        _sms = open_sms_impl(*get_at_handler());
     }
     _sms_ref_count++;
     return _sms;
@@ -389,10 +347,8 @@ void AT_CellularDevice::close_sms()
     if (_sms) {
         _sms_ref_count--;
         if (_sms_ref_count == 0) {
-            ATHandler *atHandler = &_sms->get_at_handler();
             delete _sms;
             _sms = NULL;
-            release_at_handler(atHandler);
         }
     }
 }
@@ -413,10 +369,8 @@ void AT_CellularDevice::close_network()
     if (_network) {
         _network_ref_count--;
         if (_network_ref_count == 0) {
-            ATHandler *atHandler = &_network->get_at_handler();
             delete _network;
             _network = NULL;
-            release_at_handler(atHandler);
         }
     }
 }
@@ -426,10 +380,8 @@ void AT_CellularDevice::close_information()
     if (_information) {
         _info_ref_count--;
         if (_info_ref_count == 0) {
-            ATHandler *atHandler = &_information->get_at_handler();
             delete _information;
             _information = NULL;
-            release_at_handler(atHandler);
         }
     }
 }
@@ -438,7 +390,7 @@ void AT_CellularDevice::set_timeout(int timeout)
 {
     _default_timeout = timeout;
 
-    ATHandler::set_at_timeout_list(_default_timeout, true);
+    _at.set_at_timeout(_default_timeout, true);
 
     if (_state_machine) {
         _state_machine->set_timeout(_default_timeout);
@@ -448,23 +400,22 @@ void AT_CellularDevice::set_timeout(int timeout)
 void AT_CellularDevice::modem_debug_on(bool on)
 {
     _modem_debug_on = on;
-
+    _at.set_debug(_modem_debug_on);
-    ATHandler::set_debug_list(_modem_debug_on);
 }
 
 nsapi_error_t AT_CellularDevice::init()
 {
     setup_at_handler();
 
-    _at->lock();
+    _at.lock();
     for (int retry = 1; retry <= 3; retry++) {
-        _at->clear_error();
+        _at.clear_error();
-        _at->flush();
+        _at.flush();
-        _at->at_cmd_discard("E0", "");
+        _at.at_cmd_discard("E0", "");
-        if (_at->get_last_error() == NSAPI_ERROR_OK) {
+        if (_at.get_last_error() == NSAPI_ERROR_OK) {
-            _at->at_cmd_discard("+CMEE", "=1");
+            _at.at_cmd_discard("+CMEE", "=1");
-            _at->at_cmd_discard("+CFUN", "=1");
+            _at.at_cmd_discard("+CFUN", "=1");
-            if (_at->get_last_error() == NSAPI_ERROR_OK) {
+            if (_at.get_last_error() == NSAPI_ERROR_OK) {
                 break;
             }
         }
@@ -472,27 +423,27 @@ nsapi_error_t AT_CellularDevice::init()
         rtos::ThisThread::sleep_for(100); // let modem have time to get ready
     }
 
-    return _at->unlock_return_error();
+    return _at.unlock_return_error();
 }
 
 nsapi_error_t AT_CellularDevice::shutdown()
 {
     CellularDevice::shutdown();
 
-    return _at->at_cmd_discard("+CFUN", "=0");
+    return _at.at_cmd_discard("+CFUN", "=0");
 }
 
 nsapi_error_t AT_CellularDevice::is_ready()
 {
-    _at->lock();
+    _at.lock();
-    _at->at_cmd_discard("", "");
+    _at.at_cmd_discard("", "");
 
     // we need to do this twice because for example after data mode the first 'AT' command will give modem a
     // stimulus that we are back to command mode.
-    _at->clear_error();
+    _at.clear_error();
-    _at->at_cmd_discard("", "");
+    _at.at_cmd_discard("", "");
 
-    return _at->unlock_return_error();
+    return _at.unlock_return_error();
 }
 
 void AT_CellularDevice::set_ready_cb(Callback<void()> callback)
@@ -501,11 +452,11 @@ void AT_CellularDevice::set_ready_cb(Callback<void()> callback)
 
 nsapi_error_t AT_CellularDevice::set_power_save_mode(int periodic_time, int active_time)
 {
-    _at->lock();
+    _at.lock();
 
     if (periodic_time == 0 && active_time == 0) {
         // disable PSM
-        _at->at_cmd_discard("+CPSMS", "=0");
+        _at.at_cmd_discard("+CPSMS", "=0");
     } else {
         const int PSMTimerBits = 5;
 
@@ -607,9 +558,9 @@ nsapi_error_t AT_CellularDevice::set_power_save_mode(int periodic_time, int acti
 
         // request for both GPRS and LTE
 
-        _at->at_cmd_discard("+CPSMS", "=1,", "%s%s%s%s", pt, at, pt, at);
+        _at.at_cmd_discard("+CPSMS", "=1,", "%s%s%s%s", pt, at, pt, at);
 
-        if (_at->get_last_error() != NSAPI_ERROR_OK) {
+        if (_at.get_last_error() != NSAPI_ERROR_OK) {
             tr_warn("Power save mode not enabled!");
         } else {
             // network may not agree with power save options but
@@ -617,7 +568,7 @@ nsapi_error_t AT_CellularDevice::set_power_save_mode(int periodic_time, int acti
         }
     }
 
-    return _at->unlock_return_error();
+    return _at.unlock_return_error();
 }
 
 void AT_CellularDevice::cellular_callback(nsapi_event_t ev, intptr_t ptr, CellularContext *ctx)
@@ -629,7 +580,7 @@ void AT_CellularDevice::cellular_callback(nsapi_event_t ev, intptr_t ptr, Cellul
             int timeout = *(int *)data->data;
             if (_default_timeout != timeout) {
                 _default_timeout = timeout;
-                ATHandler::set_at_timeout_list(_default_timeout, true);
+                _at.set_at_timeout(_default_timeout, true);
             }
         }
     }
@@ -654,7 +605,7 @@ nsapi_error_t AT_CellularDevice::set_baud_rate(int baud_rate)
         return error;
     }
 
-    _at->set_baud(baud_rate);
+    _at.set_baud(baud_rate);
 
     // Give some time before starting using the UART with the new baud rate
     rtos::ThisThread::sleep_for(3000);
@@ -664,7 +615,7 @@ nsapi_error_t AT_CellularDevice::set_baud_rate(int baud_rate)
 
 nsapi_error_t AT_CellularDevice::set_baud_rate_impl(int baud_rate)
 {
-    return _at->at_cmd_discard("+IPR", "=", "%d", baud_rate);
+    return _at.at_cmd_discard("+IPR", "=", "%d", baud_rate);
 }
 
 void AT_CellularDevice::set_cellular_properties(const intptr_t *property_array)

features/cellular/framework/AT/AT_CellularDevice.h

@@ -19,14 +19,15 @@
 #define AT_CELLULAR_DEVICE_H_
 
 #include "CellularDevice.h"
+#include "ATHandler.h"
 
 namespace mbed {
 
-class ATHandler;
 class AT_CellularInformation;
 class AT_CellularNetwork;
 class AT_CellularSMS;
 class AT_CellularContext;
+class FileHandle;
 
 /**
  *  Class AT_CellularDevice
@@ -83,17 +84,13 @@ public:
 
     virtual nsapi_error_t get_sim_state(SimState &state);
 
-    virtual CellularContext *create_context(FileHandle *fh = NULL, const char *apn = NULL, bool cp_req = false, bool nonip_req = false);
+    virtual CellularContext *create_context(const char *apn = NULL, bool cp_req = false, bool nonip_req = false);
-
-#if (DEVICE_SERIAL && DEVICE_INTERRUPTIN) || defined(DOXYGEN_ONLY)
-    virtual CellularContext *create_context(BufferedSerial *serial, const char *const apn, PinName dcd_pin = NC, bool active_high = false, bool cp_req = false, bool nonip_req = false);
-#endif // #if DEVICE_SERIAL
 
     virtual void delete_context(CellularContext *context);
 
-    virtual CellularNetwork *open_network(FileHandle *fh = NULL);
+    virtual CellularNetwork *open_network();
 
-    virtual CellularInformation *open_information(FileHandle *fh = NULL);
+    virtual CellularInformation *open_information();
 
     virtual void close_network();
 
@@ -113,24 +110,14 @@ public:
 
     virtual nsapi_error_t set_power_save_mode(int periodic_time, int active_time = 0);
 
-
-    virtual ATHandler *get_at_handler(FileHandle *fh);
-
     virtual ATHandler *get_at_handler();
 
-    /** Releases the given at_handler. If last reference to at_hander then it's deleted.
-     *
-     *  @param at_handler
-     *  @return NSAPI_ERROR_OK on success, NSAPI_ERROR_PARAMETER on failure
-     */
-    virtual nsapi_error_t release_at_handler(ATHandler *at_handler);
-
     virtual CellularContext *get_context_list() const;
 
     virtual nsapi_error_t set_baud_rate(int baud_rate);
 
 #if MBED_CONF_CELLULAR_USE_SMS
-    virtual CellularSMS *open_sms(FileHandle *fh = NULL);
+    virtual CellularSMS *open_sms();
 
     virtual void close_sms();
 #endif
@@ -199,7 +186,7 @@ private:
     void urc_pdn_deact();
 
 protected:
-    ATHandler *_at;
+    ATHandler _at;
 
 private:
 #if MBED_CONF_CELLULAR_USE_SMS

features/cellular/framework/AT/AT_CellularInformation.cpp

@@ -98,8 +98,3 @@ nsapi_error_t AT_CellularInformation::get_iccid(char *buf, size_t buf_size)
     }
     return _at.at_cmd_str("+CCID", "?", buf, buf_size);
 }
-
-ATHandler &AT_CellularInformation::get_at_handler()
-{
-    return _at;
-}

features/cellular/framework/AT/AT_CellularInformation.h

@@ -48,8 +48,6 @@ public:
 
     virtual nsapi_error_t get_iccid(char *buf, size_t buf_size);
 
-    ATHandler &get_at_handler();
-
 protected:
     /** Request information text from cellular device
      *

features/cellular/framework/AT/AT_CellularNetwork.cpp

@@ -710,8 +710,3 @@ nsapi_error_t AT_CellularNetwork::clear()
 
     return _at.unlock_return_error();
 }
-
-ATHandler &AT_CellularNetwork::get_at_handler()
-{
-    return _at;
-}

features/cellular/framework/AT/AT_CellularNetwork.h

@@ -96,9 +96,6 @@ public: // CellularNetwork
 
     virtual nsapi_error_t set_packet_domain_event_reporting(bool on);
 
-public:
-    ATHandler &get_at_handler();
-
 protected:
     /** Sets access technology to be scanned. Modem specific implementation.
      *

features/cellular/framework/AT/AT_CellularSMS.cpp

@@ -1252,9 +1252,4 @@ uint16_t AT_CellularSMS::unpack_7_bit_gsm_to_str(const char *str, int len, char
     return decodedCount;
 }
 
-ATHandler &AT_CellularSMS::get_at_handler()
-{
-    return _at;
-}
-
 #endif //MBED_CONF_CELLULAR_USE_SMS

features/cellular/framework/AT/AT_CellularSMS.h

@@ -62,9 +62,6 @@ public:
 
     virtual void set_extra_sim_wait_time(int sim_wait_time);
 
-public:
-    ATHandler &get_at_handler();
-
 private:
     struct sms_info_t {
         char date[SMS_MAX_TIME_STAMP_SIZE];

features/cellular/framework/device/ATHandler.cpp

@@ -63,99 +63,11 @@ static const uint8_t map_3gpp_errors[][2] =  {
     { 146, 46 }, { 178, 65 }, { 179, 66 }, { 180, 48 }, { 181, 83 }, { 171, 49 },
 };
 
-ATHandler *ATHandler::_atHandlers = NULL;
-
-// each parser is associated with one filehandle (that is UART)
-ATHandler *ATHandler::get_instance(FileHandle *fileHandle, events::EventQueue &queue, uint32_t timeout,
-                                   const char *delimiter, uint16_t send_delay, bool debug_on)
-{
-    if (!fileHandle) {
-        return NULL;
-    }
-
-    singleton_lock();
-    ATHandler *atHandler = _atHandlers;
-    while (atHandler) {
-        if (atHandler->get_file_handle() == fileHandle) {
-            atHandler->inc_ref_count();
-            singleton_unlock();
-            return atHandler;
-        }
-        atHandler = atHandler->_nextATHandler;
-    }
-
-    atHandler = new ATHandler(fileHandle, queue, timeout, delimiter, send_delay);
-    if (debug_on) {
-        atHandler->set_debug(debug_on);
-    }
-    atHandler->_nextATHandler = _atHandlers;
-    _atHandlers = atHandler;
-
-    singleton_unlock();
-    return atHandler;
-}
-
-nsapi_error_t ATHandler::close()
-{
-    if (get_ref_count() == 0) {
-        return NSAPI_ERROR_PARAMETER;
-    }
-
-    singleton_lock();
-    dec_ref_count();
-    if (get_ref_count() == 0) {
-        // we can delete this at_handler
-        ATHandler *atHandler = _atHandlers;
-        ATHandler *prev = NULL;
-        while (atHandler) {
-            if (atHandler == this) {
-                if (prev == NULL) {
-                    _atHandlers = _atHandlers->_nextATHandler;
-                } else {
-                    prev->_nextATHandler = atHandler->_nextATHandler;
-                }
-                delete this;
-                break;
-            } else {
-                prev = atHandler;
-                atHandler = atHandler->_nextATHandler;
-            }
-        }
-    }
-    singleton_unlock();
-    return NSAPI_ERROR_OK;
-}
-
-void ATHandler::set_at_timeout_list(uint32_t timeout_milliseconds, bool default_timeout)
-{
-    ATHandler *atHandler = _atHandlers;
-    singleton_lock();
-    while (atHandler) {
-        atHandler->set_at_timeout(timeout_milliseconds, default_timeout);
-        atHandler = atHandler->_nextATHandler;
-    }
-    singleton_unlock();
-}
-
-bool ATHandler::ok_to_proceed()
-{
-    if (_last_err != NSAPI_ERROR_OK) {
-        return false;
-    }
-
-    if (!_is_fh_usable) {
-        _last_err = NSAPI_ERROR_BUSY;
-        return false;
-    }
-    return true;
-}
-
 ATHandler::ATHandler(FileHandle *fh, EventQueue &queue, uint32_t timeout, const char *output_delimiter, uint16_t send_delay) :
-    _nextATHandler(0),
 #if defined AT_HANDLER_MUTEX && defined MBED_CONF_RTOS_PRESENT
     _oobCv(_fileHandleMutex),
 #endif
-    _fileHandle(NULL), // filehandle is set by set_file_handle()
+    _fileHandle(fh),
     _queue(queue),
     _last_err(NSAPI_ERROR_OK),
     _last_3gpp_error(0),
@@ -197,35 +109,15 @@ ATHandler::ATHandler(FileHandle *fh, EventQueue &queue, uint32_t timeout, const
     set_tag(&_info_stop, CRLF);
     set_tag(&_elem_stop, ")");
 
-    set_file_handle(fh);
+    set_is_filehandle_usable(true);
-}
-
-
-void ATHandler::set_debug(bool debug_on)
-{
-    _debug_on = debug_on;
-}
-
-bool ATHandler::get_debug() const
-{
-    return _debug_on;
-}
-
-void ATHandler::set_debug_list(bool debug_on)
-{
-    ATHandler *atHandler = _atHandlers;
-    singleton_lock();
-    while (atHandler) {
-        atHandler->set_debug(debug_on);
-        atHandler = atHandler->_nextATHandler;
-    }
-    singleton_unlock();
 }
 
 ATHandler::~ATHandler()
 {
     ScopedLock <ATHandler> lock(*this);
-    set_file_handle(NULL);
+
+    set_is_filehandle_usable(false);
+    _fileHandle = NULL;
 
     if (_event_id != 0 && _queue.cancel(_event_id)) {
         _event_id = 0;
@@ -250,19 +142,27 @@ ATHandler::~ATHandler()
     }
 }
 
-void ATHandler::inc_ref_count()
+bool ATHandler::ok_to_proceed()
 {
-    _ref_count++;
+    if (_last_err != NSAPI_ERROR_OK) {
+        return false;
+    }
+
+    if (!_is_fh_usable) {
+        _last_err = NSAPI_ERROR_BUSY;
+        return false;
+    }
+    return true;
 }
 
-void ATHandler::dec_ref_count()
+void ATHandler::set_debug(bool debug_on)
 {
-    _ref_count--;
+    _debug_on = debug_on;
 }
 
-int ATHandler::get_ref_count()
+bool ATHandler::get_debug() const
 {
-    return _ref_count;
+    return _debug_on;
 }
 
 FileHandle *ATHandler::get_file_handle()
@@ -270,18 +170,6 @@ FileHandle *ATHandler::get_file_handle()
     return _fileHandle;
 }
 
-void ATHandler::set_file_handle(FileHandle *fh)
-{
-    ScopedLock<ATHandler> lock(*this);
-    if (_fileHandle) {
-        set_is_filehandle_usable(false);
-    }
-    _fileHandle = fh;
-    if (_fileHandle) {
-        set_is_filehandle_usable(true);
-    }
-}
-
 void ATHandler::set_is_filehandle_usable(bool usable)
 {
     ScopedLock<ATHandler> lock(*this);

features/cellular/framework/device/CellularContext.cpp

@@ -32,12 +32,7 @@ MBED_WEAK CellularContext *CellularContext::get_default_instance()
         return NULL;
     }
 
-    static CellularContext *context = dev->create_context(NULL, NULL, MBED_CONF_CELLULAR_CONTROL_PLANE_OPT);
+    static CellularContext *context = dev->create_context(NULL, MBED_CONF_CELLULAR_CONTROL_PLANE_OPT);
-#if (DEVICE_SERIAL && DEVICE_INTERRUPTIN) || defined(DOXYGEN_ONLY)
-#if defined(MDMDCD) && defined(MDM_PIN_POLARITY)
-    context->set_file_handle(static_cast<BufferedSerial *>(&dev->get_file_handle()), MDMDCD, MDM_PIN_POLARITY);
-#endif // #if defined(MDMDCD) && defined(MDM_PIN_POLARITY)
-#endif // #if DEVICE_SERIAL
     return context;
 }
 
@@ -49,19 +44,14 @@ MBED_WEAK CellularContext *CellularContext::get_default_nonip_instance()
         return NULL;
     }
 
-    static CellularContext *context = dev->create_context(NULL, NULL, MBED_CONF_CELLULAR_CONTROL_PLANE_OPT, true);
+    static CellularContext *context = dev->create_context(NULL, MBED_CONF_CELLULAR_CONTROL_PLANE_OPT, true);
-#if (DEVICE_SERIAL && DEVICE_INTERRUPTIN) || defined(DOXYGEN_ONLY)
-#if defined(MDMDCD) && defined(MDM_PIN_POLARITY)
-    context->set_file_handle(static_cast<BufferedSerial *>(&dev->get_file_handle()), MDMDCD, MDM_PIN_POLARITY);
-#endif // #if defined(MDMDCD) && defined(MDM_PIN_POLARITY)
-#endif // #if DEVICE_SERIAL
     return context;
 }
 
 CellularContext::CellularContext() : _next(0), _stack(0), _pdp_type(DEFAULT_PDP_TYPE),
     _authentication_type(CellularContext::CHAP), _connect_status(NSAPI_STATUS_DISCONNECTED), _status_cb(),
     _cid(-1), _new_context_set(false), _is_context_active(false), _is_context_activated(false),
-    _apn(0), _uname(0), _pwd(0), _dcd_pin(NC), _active_high(false), _cp_netif(0), _retry_timeout_array(),
+    _apn(0), _uname(0), _pwd(0), _cp_netif(0), _retry_timeout_array(),
     _retry_array_length(0), _retry_count(0), _device(0), _nw(0), _is_blocking(true), _nonip_req(false), _cp_in_use(false)
 {
 }

features/cellular/framework/device/CellularDevice.cpp

@@ -34,18 +34,17 @@ MBED_WEAK CellularDevice *CellularDevice::get_target_default_instance()
     return NULL;
 }
 
-CellularDevice::CellularDevice(FileHandle *fh) :
+CellularDevice::CellularDevice() :
     _network_ref_count(0),
 #if MBED_CONF_CELLULAR_USE_SMS
     _sms_ref_count(0),
 #endif //MBED_CONF_CELLULAR_USE_SMS
-    _info_ref_count(0), _fh(fh), _queue(10 * EVENTS_EVENT_SIZE), _state_machine(0),
+    _info_ref_count(0), _queue(10 * EVENTS_EVENT_SIZE), _state_machine(0),
     _status_cb(), _nw(0)
 #ifdef MBED_CONF_RTOS_PRESENT
     , _queue_thread(osPriorityNormal, 2048, NULL, "cellular_queue")
 #endif // MBED_CONF_RTOS_PRESENT
 {
-    MBED_ASSERT(fh);
     set_sim_pin(NULL);
     set_plmn(NULL);
 
@@ -64,11 +63,6 @@ CellularDevice::~CellularDevice()
     delete _state_machine;
 }
 
-FileHandle &CellularDevice::get_file_handle() const
-{
-    return *_fh;
-}
-
 events::EventQueue *CellularDevice::get_queue()
 {
     return &_queue;
@@ -130,7 +124,7 @@ nsapi_error_t CellularDevice::create_state_machine()
 {
     nsapi_error_t err = NSAPI_ERROR_OK;
     if (!_state_machine) {
-        _nw = open_network(_fh);
+        _nw = open_network();
         // Attach to network so we can get update status from the network
         _nw->attach(callback(this, &CellularDevice::stm_callback));
         _state_machine = new CellularStateMachine(*this, *get_queue(), *_nw);

features/cellular/framework/targets/GEMALTO/CINTERION/GEMALTO_CINTERION_CellularContext.cpp

@@ -39,7 +39,7 @@ NetworkStack *GEMALTO_CINTERION_CellularContext::get_stack()
     }
 
     if (!_stack) {
-        _stack = new GEMALTO_CINTERION_CellularStack(get_at_handler(), _apn, _uname, _pwd, _cid, (nsapi_ip_stack_t)_pdp_type, *get_device());
+        _stack = new GEMALTO_CINTERION_CellularStack(_at, _apn, _uname, _pwd, _cid, (nsapi_ip_stack_t)_pdp_type, *get_device());
         if (static_cast<GEMALTO_CINTERION_CellularStack *>(_stack)->socket_stack_init() != NSAPI_ERROR_OK) {
             delete _stack;
             _stack = NULL;

features/cellular/framework/targets/QUECTEL/BC95/QUECTEL_BC95.cpp

@@ -58,10 +58,10 @@ QUECTEL_BC95::QUECTEL_BC95(FileHandle *fh) : AT_CellularDevice(fh)
 
 nsapi_error_t QUECTEL_BC95::get_sim_state(SimState &state)
 {
-    _at->lock();
+    _at.lock();
-    _at->flush();
+    _at.flush();
-    nsapi_error_t err = _at->at_cmd_discard("+NCCID", "?");
+    nsapi_error_t err = _at.at_cmd_discard("+NCCID", "?");
-    _at->unlock();
+    _at.unlock();
 
     state = SimStateReady;
     if (err != NSAPI_ERROR_OK) {
@@ -91,25 +91,25 @@ nsapi_error_t QUECTEL_BC95::init()
 {
     setup_at_handler();
 
-    _at->lock();
+    _at.lock();
-    _at->flush();
+    _at.flush();
-    nsapi_error_t err = _at->at_cmd_discard("", "");  //Send AT
+    nsapi_error_t err = _at.at_cmd_discard("", "");  //Send AT
     if (!err) {
-        err = _at->at_cmd_discard("+CMEE", "=1"); // verbose responses
+        err = _at.at_cmd_discard("+CMEE", "=1"); // verbose responses
     }
     if (!err) {
-        err = _at->at_cmd_discard("+CFUN", "=", "%d", 1);
+        err = _at.at_cmd_discard("+CFUN", "=", "%d", 1);
     }
     if (!err) {
-        err = _at->get_last_error();
+        err = _at.get_last_error();
     }
-    _at->unlock();
+    _at.unlock();
     return err;
 }
 
 nsapi_error_t QUECTEL_BC95::set_baud_rate_impl(int baud_rate)
 {
-    return _at->at_cmd_discard("+NATSPEED", "=", "%d%d%d%d%d%d%d", baud_rate, 30, 0, 2, 1, 0, 0);
+    return _at.at_cmd_discard("+NATSPEED", "=", "%d%d%d%d%d%d%d", baud_rate, 30, 0, 2, 1, 0, 0);
 }
 
 #if MBED_CONF_QUECTEL_BC95_PROVIDE_DEFAULT

features/cellular/framework/targets/QUECTEL/BG96/QUECTEL_BG96.cpp

@@ -79,7 +79,7 @@ QUECTEL_BG96::QUECTEL_BG96(FileHandle *fh, PinName pwr, bool active_high, PinNam
 
 void QUECTEL_BG96::set_at_urcs_impl()
 {
-    _at->set_urc_handler("+QIURC: \"pdpde",  mbed::Callback<void()>(this, &QUECTEL_BG96::urc_pdpdeact));
+    _at.set_urc_handler("+QIURC: \"pdpde",  mbed::Callback<void()>(this, &QUECTEL_BG96::urc_pdpdeact));
 }
 
 AT_CellularNetwork *QUECTEL_BG96::open_network_impl(ATHandler &at)
@@ -99,7 +99,7 @@ AT_CellularInformation *QUECTEL_BG96::open_information_impl(ATHandler &at)
 
 void QUECTEL_BG96::set_ready_cb(Callback<void()> callback)
 {
-    _at->set_urc_handler(DEVICE_READY_URC, callback);
+    _at.set_urc_handler(DEVICE_READY_URC, callback);
 }
 
 nsapi_error_t QUECTEL_BG96::soft_power_on()
@@ -117,7 +117,7 @@ nsapi_error_t QUECTEL_BG96::soft_power_on()
     }
 
 #if defined (MBED_CONF_QUECTEL_BG96_RTS) && defined(MBED_CONF_QUECTEL_BG96_CTS)
-    if (_at->at_cmd_discard("+IFC", "=", "%d%d", 2, 2) != NSAPI_ERROR_OK) {
+    if (_at.at_cmd_discard("+IFC", "=", "%d%d", 2, 2) != NSAPI_ERROR_OK) {
         tr_warn("Set flow control failed");
         return NSAPI_ERROR_DEVICE_ERROR;
     }
@@ -128,16 +128,16 @@ nsapi_error_t QUECTEL_BG96::soft_power_on()
 
 nsapi_error_t QUECTEL_BG96::soft_power_off()
 {
-    _at->lock();
+    _at.lock();
-    _at->cmd_start("AT+QPOWD");
+    _at.cmd_start("AT+QPOWD");
-    _at->cmd_stop_read_resp();
+    _at.cmd_stop_read_resp();
-    if (_at->get_last_error() != NSAPI_ERROR_OK) {
+    if (_at.get_last_error() != NSAPI_ERROR_OK) {
         tr_warn("Force modem off");
         if (_pwr.is_connected()) {
             press_button(_pwr, 650); // BG96_Hardware_Design_V1.1: Power off signal at least 650 ms
         }
     }
-    return _at->unlock_return_error();
+    return _at.unlock_return_error();
 }
 
 #if MBED_CONF_QUECTEL_BG96_PROVIDE_DEFAULT
@@ -159,10 +159,10 @@ CellularDevice *CellularDevice::get_default_instance()
 
 void QUECTEL_BG96::urc_pdpdeact()
 {
-    _at->lock();
+    _at.lock();
-    _at->skip_param();
+    _at.skip_param();
-    int cid = _at->read_int();
+    int cid = _at.read_int();
-    const nsapi_error_t err = _at->unlock_return_error();
+    const nsapi_error_t err = _at.unlock_return_error();
 
     if (err != NSAPI_ERROR_OK) {
         return;
@@ -183,14 +183,14 @@ void QUECTEL_BG96::press_button(DigitalOut &button, uint32_t timeout)
 bool QUECTEL_BG96::wake_up(bool reset)
 {
     // check if modem is already ready
-    _at->lock();
+    _at.lock();
-    _at->flush();
+    _at.flush();
-    _at->set_at_timeout(30);
+    _at.set_at_timeout(30);
-    _at->cmd_start("AT");
+    _at.cmd_start("AT");
-    _at->cmd_stop_read_resp();
+    _at.cmd_stop_read_resp();
-    nsapi_error_t err = _at->get_last_error();
+    nsapi_error_t err = _at.get_last_error();
-    _at->restore_at_timeout();
+    _at.restore_at_timeout();
-    _at->unlock();
+    _at.unlock();
     // modem is not responding, power it on
     if (err != NSAPI_ERROR_OK) {
         if (!reset) {
@@ -201,20 +201,20 @@ bool QUECTEL_BG96::wake_up(bool reset)
             tr_warn("Reset modem");
             press_button(_rst, 150); // BG96_Hardware_Design_V1.1 requires RESET_N timeout at least 150 ms
         }
-        _at->lock();
+        _at.lock();
         // According to BG96_Hardware_Design_V1.1 USB is active after 4.2s, but it seems to take over 5s
-        _at->set_at_timeout(6000);
+        _at.set_at_timeout(6000);
-        _at->resp_start();
+        _at.resp_start();
-        _at->set_stop_tag("RDY");
+        _at.set_stop_tag("RDY");
-        bool rdy = _at->consume_to_stop_tag();
+        bool rdy = _at.consume_to_stop_tag();
-        _at->set_stop_tag(OK);
+        _at.set_stop_tag(OK);
-        _at->restore_at_timeout();
+        _at.restore_at_timeout();
-        _at->unlock();
+        _at.unlock();
         if (!rdy) {
             return false;
         }
     }
 
     // sync to check that AT is really responsive and to clear garbage
-    return _at->sync(500);
+    return _at.sync(500);
 }

features/cellular/framework/targets/QUECTEL/EC2X/QUECTEL_EC2X.cpp

@@ -124,15 +124,15 @@ nsapi_error_t QUECTEL_EC2X::soft_power_on()
         _rst = !_active_high;
         ThisThread::sleep_for(100);
 
-        _at->lock();
+        _at.lock();
 
-        _at->set_at_timeout(5000);
+        _at.set_at_timeout(5000);
-        _at->resp_start();
+        _at.resp_start();
-        _at->set_stop_tag("RDY");
+        _at.set_stop_tag("RDY");
-        bool rdy = _at->consume_to_stop_tag();
+        bool rdy = _at.consume_to_stop_tag();
-        _at->set_stop_tag(OK);
+        _at.set_stop_tag(OK);
 
-        _at->unlock();
+        _at.unlock();
 
         if (!rdy) {
             return NSAPI_ERROR_DEVICE_ERROR;

features/cellular/framework/targets/QUECTEL/M26/QUECTEL_M26.cpp

@@ -56,10 +56,10 @@ nsapi_error_t QUECTEL_M26::get_sim_state(SimState &state)
 {
     char buf[13];
 
-    _at->lock();
+    _at.lock();
-    nsapi_error_t err = _at->at_cmd_str("+CPIN", "?", buf, 13);
+    nsapi_error_t err = _at.at_cmd_str("+CPIN", "?", buf, 13);
     tr_debug("CPIN: %s", buf);
-    _at->unlock();
+    _at.unlock();
 
     if (memcmp(buf, "READY", 5) == 0) {
         state = SimStateReady;
@@ -89,7 +89,7 @@ AT_CellularContext *QUECTEL_M26::create_context_impl(ATHandler &at, const char *
 
 nsapi_error_t QUECTEL_M26::shutdown()
 {
-    return _at->at_cmd_discard("+QPOWD", "=0");
+    return _at.at_cmd_discard("+QPOWD", "=0");
 }
 
 

features/cellular/framework/targets/RiotMicro/AT/RM1000_AT.cpp

@@ -74,18 +74,18 @@ nsapi_error_t RM1000_AT::init()
 {
     tr_debug("RM1000_AT::init");
 
-    _at->lock();
+    _at.lock();
-    _at->flush();
+    _at.flush();
-    _at->at_cmd_discard("E0", ""); // echo off
+    _at.at_cmd_discard("E0", ""); // echo off
 
-    _at->at_cmd_discard("+SIM", "=physical");
+    _at.at_cmd_discard("+SIM", "=physical");
 
-    _at->set_at_timeout(5000);
+    _at.set_at_timeout(5000);
-    _at->at_cmd_discard("+CFUN", "=1"); // set full functionality
+    _at.at_cmd_discard("+CFUN", "=1"); // set full functionality
 
-    _at->at_cmd_discard("+VERBOSE", "=0"); // verbose responses
+    _at.at_cmd_discard("+VERBOSE", "=0"); // verbose responses
 
-    return _at->unlock_return_error();
+    return _at.unlock_return_error();
 }
 
 #if MBED_CONF_RM1000_AT_PROVIDE_DEFAULT

features/cellular/framework/targets/TELIT/HE910/TELIT_HE910.cpp

@@ -55,7 +55,7 @@ nsapi_error_t TELIT_HE910::init()
     if (err != NSAPI_ERROR_OK) {
         return err;
     }
-    return _at->at_cmd_discard("&K0;&C1;&D0", "");
+    return _at.at_cmd_discard("&K0;&C1;&D0", "");
 }
 
 #if MBED_CONF_TELIT_HE910_PROVIDE_DEFAULT

features/cellular/framework/targets/TELIT/ME910/TELIT_ME910.cpp

@@ -84,11 +84,11 @@ nsapi_error_t TELIT_ME910::init()
     if (err != NSAPI_ERROR_OK) {
         return err;
     }
-    _at->lock();
+    _at.lock();
 #if defined (MBED_CONF_TELIT_ME910_RTS) && defined (MBED_CONF_TELIT_ME910_CTS)
-    _at->at_cmd_discard("&K3;&C1;&D0", "");
+    _at.at_cmd_discard("&K3;&C1;&D0", "");
 #else
-    _at->at_cmd_discard("&K0;&C1;&D0", "");
+    _at.at_cmd_discard("&K0;&C1;&D0", "");
 #endif
 
     // AT#QSS=1
@@ -100,7 +100,7 @@ nsapi_error_t TELIT_ME910::init()
     // <status> values:
     // - 0: SIM not inserted
     // - 1: SIM inserted
-    _at->at_cmd_discard("#QSS", "=1");
+    _at.at_cmd_discard("#QSS", "=1");
 
     // AT#PSNT=1
     // Set command enables unsolicited result code for packet service network type (PSNT)
@@ -110,7 +110,7 @@ nsapi_error_t TELIT_ME910::init()
     // - 0: GPRS network
     // - 4: LTE network
     // - 5: unknown or not registered
-    _at->at_cmd_discard("#PSNT", "=1");
+    _at.at_cmd_discard("#PSNT", "=1");
 
     // AT+CMER=2
     // Set command enables sending of unsolicited result codes from TA to TE in the case of
@@ -118,7 +118,7 @@ nsapi_error_t TELIT_ME910::init()
     // Current setting: buffer +CIEV Unsolicited Result Codes in the TA when TA-TE link is
     // reserved (e.g. on-line data mode) and flush them to the TE after
     // reservation; otherwise forward them directly to the TE
-    _at->at_cmd_discard("+CMER", "=2");
+    _at.at_cmd_discard("+CMER", "=2");
 
     // AT+CMEE=2
     // Set command disables the use of result code +CME ERROR: <err> as an indication of an
@@ -126,16 +126,16 @@ nsapi_error_t TELIT_ME910::init()
     // ERROR: <err> final result code instead of the default ERROR final result code. ERROR is returned
     // normally when the error message is related to syntax, invalid parameters or DTE functionality.
     // Current setting: enable and use verbose <err> values
-    _at->at_cmd_discard("+CMEE", "=2");
+    _at.at_cmd_discard("+CMEE", "=2");
 
     // AT&W&P
     // - AT&W: Execution command stores on profile <n> the complete configuration of the device. If
     //         parameter is omitted, the command has the same behavior of AT&W0.
     // - AT&P: Execution command defines which full profile will be loaded at startup. If parameter
     //         is omitted, the command has the same behavior as AT&P0
-    _at->at_cmd_discard("&W&P", "");
+    _at.at_cmd_discard("&W&P", "");
 
-    return _at->unlock_return_error();
+    return _at.unlock_return_error();
 }
 
 #if MBED_CONF_TELIT_ME910_PROVIDE_DEFAULT

features/cellular/framework/targets/UBLOX/AT/UBLOX_AT.cpp

@@ -129,9 +129,9 @@ nsapi_error_t UBLOX_AT::init()
 {
     setup_at_handler();
 
-    _at->lock();
+    _at.lock();
-    _at->flush();
+    _at.flush();
-    _at->at_cmd_discard("", "");
+    _at.at_cmd_discard("", "");
     int value = -1;
 
 #ifdef UBX_MDM_SARA_G3XX
@@ -139,19 +139,19 @@ nsapi_error_t UBLOX_AT::init()
 #elif defined(UBX_MDM_SARA_U2XX) || defined(UBX_MDM_SARA_R41XM)
     value = 4;
 #else
-    _at->unlock();
+    _at.unlock();
     return NSAPI_ERROR_UNSUPPORTED;
 #endif
 
-    nsapi_error_t err = _at->at_cmd_discard("+CFUN", "=", "%d", value);
+    nsapi_error_t err = _at.at_cmd_discard("+CFUN", "=", "%d", value);
 
     if (err == NSAPI_ERROR_OK) {
-        _at->at_cmd_discard("E0", ""); // echo off
+        _at.at_cmd_discard("E0", ""); // echo off
-        _at->at_cmd_discard("+CMEE", "=1"); // verbose responses
+        _at.at_cmd_discard("+CMEE", "=1"); // verbose responses
         config_authentication_parameters();
-        err = _at->at_cmd_discard("+CFUN", "=1"); // set full functionality
+        err = _at.at_cmd_discard("+CFUN", "=1"); // set full functionality
     }
-    return _at->unlock_return_error();
+    return _at.unlock_return_error();
 }
 
 nsapi_error_t UBLOX_AT::config_authentication_parameters()
@@ -191,19 +191,19 @@ nsapi_error_t UBLOX_AT::set_authentication_parameters(const char *apn,
 {
     int modem_security = ubx_context->nsapi_security_to_modem_security(auth);
 
-    nsapi_error_t err = _at->at_cmd_discard("+CGDCONT", "=", "%d%s%s", 1, "IP", apn);
+    nsapi_error_t err = _at.at_cmd_discard("+CGDCONT", "=", "%d%s%s", 1, "IP", apn);
 
     if (err == NSAPI_ERROR_OK) {
 #ifdef UBX_MDM_SARA_R41XM
         if (modem_security == CellularContext::CHAP) {
-            err = _at->at_cmd_discard("+UAUTHREQ", "=", "%d%d%s%s", 1, modem_security, password, username);
+            err = _at.at_cmd_discard("+UAUTHREQ", "=", "%d%d%s%s", 1, modem_security, password, username);
         } else if (modem_security == CellularContext::NOAUTH) {
-            err = _at->at_cmd_discard("+UAUTHREQ", "=", "%d%d", 1, modem_security);
+            err = _at.at_cmd_discard("+UAUTHREQ", "=", "%d%d", 1, modem_security);
         } else {
-            err = _at->at_cmd_discard("+UAUTHREQ", "=", "%d%d%s%s", 1, modem_security, username, password);
+            err = _at.at_cmd_discard("+UAUTHREQ", "=", "%d%d%s%s", 1, modem_security, username, password);
         }
 #else
-        err = _at->at_cmd_discard("+UAUTHREQ", "=", "%d%d%s%s", 1, modem_security, username, password);
+        err = _at.at_cmd_discard("+UAUTHREQ", "=", "%d%d%s%s", 1, modem_security, username, password);
 #endif
     }
 
@@ -213,5 +213,5 @@ nsapi_error_t UBLOX_AT::set_authentication_parameters(const char *apn,
 nsapi_error_t UBLOX_AT::get_imsi(char *imsi)
 {
     //Special case: Command put in cmd_chr to make a 1 liner
-    return _at->at_cmd_str("", "+CIMI", imsi, MAX_IMSI_LENGTH + 1);
+    return _at.at_cmd_str("", "+CIMI", imsi, MAX_IMSI_LENGTH + 1);
 }

features/cellular/framework/targets/UBLOX/N2XX/UBLOX_N2XX.cpp

@@ -51,18 +51,18 @@ UBLOX_N2XX::UBLOX_N2XX(FileHandle *fh): AT_CellularDevice(fh)
 
 void UBLOX_N2XX::set_at_urcs_impl()
 {
-    _at->set_urc_handler("+NPIN:", mbed::Callback<void()>(this, &UBLOX_N2XX::NPIN_URC));
+    _at.set_urc_handler("+NPIN:", mbed::Callback<void()>(this, &UBLOX_N2XX::NPIN_URC));
 }
 
 UBLOX_N2XX::~UBLOX_N2XX()
 {
-    _at->set_urc_handler("+NPIN:", nullptr);
+    _at.set_urc_handler("+NPIN:", nullptr);
 }
 
 // Callback for Sim Pin.
 void UBLOX_N2XX::NPIN_URC()
 {
-    _at->read_string(simstr, sizeof(simstr));
+    _at.read_string(simstr, sizeof(simstr));
 }
 
 AT_CellularNetwork *UBLOX_N2XX::open_network_impl(ATHandler &at)
@@ -86,27 +86,27 @@ nsapi_error_t UBLOX_N2XX::init()
 {
     setup_at_handler();
 
-    _at->lock();
+    _at.lock();
-    _at->flush();
+    _at.flush();
-    _at->at_cmd_discard("", "");
+    _at.at_cmd_discard("", "");
 
-    _at->at_cmd_discard("+CMEE", "=1"); // verbose responses
+    _at.at_cmd_discard("+CMEE", "=1"); // verbose responses
 
 #ifdef MBED_CONF_NSAPI_DEFAULT_CELLULAR_SIM_PIN
     set_pin(MBED_CONF_NSAPI_DEFAULT_CELLULAR_SIM_PIN);
 #endif
-    return _at->unlock_return_error();
+    return _at.unlock_return_error();
 }
 
 nsapi_error_t UBLOX_N2XX::get_sim_state(SimState &state)
 {
     nsapi_error_t error = NSAPI_ERROR_DEVICE_ERROR;
 
-    _at->lock();
+    _at.lock();
-    _at->flush();
+    _at.flush();
     //Special case: Command put in cmd_chr to make a 1 liner
-    error = _at->at_cmd_str("", "+CFUN=1", simstr, sizeof(simstr));
+    error = _at.at_cmd_str("", "+CFUN=1", simstr, sizeof(simstr));
-    _at->unlock();
+    _at.unlock();
 
     int len = strlen(simstr);
     if (len > 0 || error == NSAPI_ERROR_OK) {
@@ -157,7 +157,7 @@ nsapi_error_t UBLOX_N2XX::set_pin(const char *sim_pin)
         return NSAPI_ERROR_PARAMETER;
     }
 
-    return _at->at_cmd_discard("+NPIN", "=", "%d%s", 0, sim_pin);
+    return _at.at_cmd_discard("+NPIN", "=", "%d%s", 0, sim_pin);
 }
 
 #if MBED_CONF_UBLOX_N2XX_PROVIDE_DEFAULT

targets/TARGET_NORDIC/TARGET_NRF5x/TARGET_NRF52/TARGET_MCU_NRF52840/TARGET_EP_AGORA/ONBOARD_TELIT_ME910.cpp

@@ -67,11 +67,11 @@ nsapi_error_t ONBOARD_TELIT_ME910::init()
     if (err != NSAPI_ERROR_OK) {
         return err;
     }
-    _at->lock();
+    _at.lock();
 #if DEVICE_SERIAL_FC
-    _at->at_cmd_discard("&K3;&C1;&D0", "");
+    _at.at_cmd_discard("&K3;&C1;&D0", "");
 #else
-    _at->at_cmd_discard("&K0;&C1;&D0", "");
+    _at.at_cmd_discard("&K0;&C1;&D0", "");
 #endif
 
     // AT#QSS=1
@@ -83,7 +83,7 @@ nsapi_error_t ONBOARD_TELIT_ME910::init()
     // <status> values:
     // - 0: SIM not inserted
     // - 1: SIM inserted
-    _at->at_cmd_discard("#QSS", "=1");
+    _at.at_cmd_discard("#QSS", "=1");
 
     // AT#PSNT=1
     // Set command enables unsolicited result code for packet service network type (PSNT)
@@ -93,7 +93,7 @@ nsapi_error_t ONBOARD_TELIT_ME910::init()
     // - 0: GPRS network
     // - 4: LTE network
     // - 5: unknown or not registered
-    _at->at_cmd_discard("#PSNT", "=1");
+    _at.at_cmd_discard("#PSNT", "=1");
 
     // AT+CMER=2
     // Set command enables sending of unsolicited result codes from TA to TE in the case of
@@ -101,7 +101,7 @@ nsapi_error_t ONBOARD_TELIT_ME910::init()
     // Current setting: buffer +CIEV Unsolicited Result Codes in the TA when TA-TE link is
     // reserved (e.g. on-line data mode) and flush them to the TE after
     // reservation; otherwise forward them directly to the TE
-    _at->at_cmd_discard("+CMER", "=2");
+    _at.at_cmd_discard("+CMER", "=2");
 
     // AT+CMEE=2
     // Set command disables the use of result code +CME ERROR: <err> as an indication of an
@@ -109,21 +109,21 @@ nsapi_error_t ONBOARD_TELIT_ME910::init()
     // ERROR: <err> final result code instead of the default ERROR final result code. ERROR is returned
     // normally when the error message is related to syntax, invalid parameters or DTE functionality.
     // Current setting: enable and use verbose <err> values
-    _at->at_cmd_discard("+CMEE", "=2");
+    _at.at_cmd_discard("+CMEE", "=2");
 
     // AT#PORTCFG=0
     // Set command allows to connect Service Access Points to the external physical ports giving a great
     // flexibility. Examples of Service Access Points: AT Parser Instance #1, #2, #3, etc..
-    _at->at_cmd_discard("#PORTCFG", "=", "%d", EP_AGORA_PORT_CONFIGURATION_VARIANT);
+    _at.at_cmd_discard("#PORTCFG", "=", "%d", EP_AGORA_PORT_CONFIGURATION_VARIANT);
 
     // AT&W&P
     // - AT&W: Execution command stores on profile <n> the complete configuration of the device. If
     //         parameter is omitted, the command has the same behavior of AT&W0.
     // - AT&P: Execution command defines which full profile will be loaded at startup. If parameter
     //         is omitted, the command has the same behavior as AT&P0
-    _at->at_cmd_discard("&W&P", "");
+    _at.at_cmd_discard("&W&P", "");
 
-    return _at->unlock_return_error();
+    return _at.unlock_return_error();
 }
 
 void ONBOARD_TELIT_ME910::press_power_button(int time_ms)