From c452d8ff0e4c8a5f037da1fbb66e0eab8e25e9b3 Mon Sep 17 00:00:00 2001
From: paul-szczepanek-arm
 <33840200+paul-szczepanek-arm@users.noreply.github.com>
Date: Wed, 9 Jan 2019 09:51:39 +0000
Subject: [PATCH 01/18] add mtu events

---
 features/FEATURE_BLE/ble/gap/Gap.h            | 31 +++++++++++++++++++
 features/FEATURE_BLE/ble/generic/GenericGap.h | 11 +++++++
 features/FEATURE_BLE/ble/pal/PalGap.h         | 17 ++++++++++
 .../FEATURE_BLE/source/generic/GenericGap.cpp | 17 ++++++++++
 4 files changed, 76 insertions(+)

diff --git a/features/FEATURE_BLE/ble/gap/Gap.h b/features/FEATURE_BLE/ble/gap/Gap.h
index 98f60f4596..f859e49782 100644
--- a/features/FEATURE_BLE/ble/gap/Gap.h
+++ b/features/FEATURE_BLE/ble/gap/Gap.h
@@ -492,6 +492,37 @@ public:
         {
         }
 
+        /**
+         * Function invoked when the connections changes the ATT_MTU which controls
+         * the maximum size of an attribute that can be read in a single L2CAP packet
+         * which might be fragmented across multiple packets.
+         *
+         * @param connectionHandle The handle of the connection that changed the size.
+         * @param attMtuSize
+         */
+        virtual void onAttMtuChanged(
+            connection_handle_t connectionHandle,
+            uint16_t attMtuSize
+        )
+        {
+        }
+
+        /**
+         * Function invoked when the connections changes the maximum number of octets
+         * that can be sent or received by the controller in a single packet.
+         *
+         * @param connectionHandle The handle of the connection that changed the size.
+         * @param txSize Number of octets we can send on this connection in a single packet.
+         * @param rxSize Number of octets we can receive on this connection in a single packet.
+         */
+        virtual void onPacketPaylodSizeChanged(
+            connection_handle_t connectionHandle,
+            uint16_t txSize,
+            uint16_t rxSize
+        )
+        {
+        }
+
     protected:
         /**
          * Prevent polymorphic deletion and avoid unnecessary virtual destructor
diff --git a/features/FEATURE_BLE/ble/generic/GenericGap.h b/features/FEATURE_BLE/ble/generic/GenericGap.h
index b46bcb6716..2c8b686a0a 100644
--- a/features/FEATURE_BLE/ble/generic/GenericGap.h
+++ b/features/FEATURE_BLE/ble/generic/GenericGap.h
@@ -627,6 +627,17 @@ private:
         phy_t rx_phy
     );
 
+    virtual void on_att_mtu_changed(
+        Handle_t connection_handle,
+        uint16_t att_mtu_size
+    );
+
+    virtual void on_packet_paylod_size_changed(
+        Handle_t connection_handle,
+        uint16_t tx_size,
+        uint16_t rx_size
+    );
+
     virtual void on_phy_update_complete(
         pal::hci_error_code_t hci_status,
         Handle_t connection_handle,
diff --git a/features/FEATURE_BLE/ble/pal/PalGap.h b/features/FEATURE_BLE/ble/pal/PalGap.h
index 39e06f2622..1e3c95b1d3 100644
--- a/features/FEATURE_BLE/ble/pal/PalGap.h
+++ b/features/FEATURE_BLE/ble/pal/PalGap.h
@@ -44,6 +44,23 @@ struct Gap {
             ble::phy_t rx_phy
         ) = 0;
 
+        /**
+         * @copydoc Gap::EventHandler::onAttMtuChanged
+         */
+        virtual void on_att_mtu_changed(
+            Handle_t connection_handle,
+            uint16_t att_mtu_size
+        ) = 0;
+
+        /**
+         * @copydoc Gap::EventHandler::onPacketPaylodSizeChanged
+         */
+        virtual void on_packet_paylod_size_changed(
+            Handle_t connection_handle,
+            uint16_t tx_size,
+            uint16_t rx_size
+        ) = 0;
+
         /**
          * @copydoc Gap::EventHandler::onPhyUpdateComplete
          */
diff --git a/features/FEATURE_BLE/source/generic/GenericGap.cpp b/features/FEATURE_BLE/source/generic/GenericGap.cpp
index 4ca9b9df09..8e622906ab 100644
--- a/features/FEATURE_BLE/source/generic/GenericGap.cpp
+++ b/features/FEATURE_BLE/source/generic/GenericGap.cpp
@@ -860,6 +860,23 @@ void GenericGap::on_read_phy(
     }
 }
 
+void GenericGap::on_att_mtu_changed(
+    Handle_t connection_handle,
+    uint16_t att_mtu_size
+)
+{
+    onAttMtuChanged(connectionHandle, attMtuSize);
+}
+
+void GenericGap::on_packet_paylod_size_changed(
+    Handle_t connection_handle,
+    uint16_t tx_size,
+    uint16_t rx_size
+)
+{
+    onPacketPaylodSizeChanged(connectionHandle, txSize, rxSize);
+}
+
 void GenericGap::on_phy_update_complete(
     pal::hci_error_code_t hci_status,
     Handle_t connection_handle,

From 108d6908be4c197e86f7ed478f4bd7e9c319e304 Mon Sep 17 00:00:00 2001
From: paul-szczepanek-arm
 <33840200+paul-szczepanek-arm@users.noreply.github.com>
Date: Wed, 9 Jan 2019 15:27:46 +0000
Subject: [PATCH 02/18] route ble events to gap

---
 features/FEATURE_BLE/ble/pal/PalGap.h              |  4 ++--
 features/FEATURE_BLE/source/generic/GenericGap.cpp |  8 ++++++--
 .../targets/TARGET_CORDIO/CordioPalAttClient.h     | 13 ++++++++++++-
 .../targets/TARGET_CORDIO/source/CordioBLE.cpp     | 14 ++++++++++++++
 4 files changed, 34 insertions(+), 5 deletions(-)

diff --git a/features/FEATURE_BLE/ble/pal/PalGap.h b/features/FEATURE_BLE/ble/pal/PalGap.h
index 1e3c95b1d3..5d0a16432d 100644
--- a/features/FEATURE_BLE/ble/pal/PalGap.h
+++ b/features/FEATURE_BLE/ble/pal/PalGap.h
@@ -48,7 +48,7 @@ struct Gap {
          * @copydoc Gap::EventHandler::onAttMtuChanged
          */
         virtual void on_att_mtu_changed(
-            Handle_t connection_handle,
+            connection_handle_t connection_handle,
             uint16_t att_mtu_size
         ) = 0;
 
@@ -56,7 +56,7 @@ struct Gap {
          * @copydoc Gap::EventHandler::onPacketPaylodSizeChanged
          */
         virtual void on_packet_paylod_size_changed(
-            Handle_t connection_handle,
+            connection_handle_t connection_handle,
             uint16_t tx_size,
             uint16_t rx_size
         ) = 0;
diff --git a/features/FEATURE_BLE/source/generic/GenericGap.cpp b/features/FEATURE_BLE/source/generic/GenericGap.cpp
index 8e622906ab..72959127d7 100644
--- a/features/FEATURE_BLE/source/generic/GenericGap.cpp
+++ b/features/FEATURE_BLE/source/generic/GenericGap.cpp
@@ -865,7 +865,9 @@ void GenericGap::on_att_mtu_changed(
     uint16_t att_mtu_size
 )
 {
-    onAttMtuChanged(connectionHandle, attMtuSize);
+    if (_eventHandler) {
+        _eventHandler->onAttMtuChanged(connection_handle, att_mtu_size);
+    }
 }
 
 void GenericGap::on_packet_paylod_size_changed(
@@ -874,7 +876,9 @@ void GenericGap::on_packet_paylod_size_changed(
     uint16_t rx_size
 )
 {
-    onPacketPaylodSizeChanged(connectionHandle, txSize, rxSize);
+    if (_eventHandler) {
+        _eventHandler->onPacketPaylodSizeChanged(connection_handle, tx_size, rx_size);
+    }
 }
 
 void GenericGap::on_phy_update_complete(
diff --git a/features/FEATURE_BLE/targets/TARGET_CORDIO/CordioPalAttClient.h b/features/FEATURE_BLE/targets/TARGET_CORDIO/CordioPalAttClient.h
index cff00fceea..83d79454d0 100644
--- a/features/FEATURE_BLE/targets/TARGET_CORDIO/CordioPalAttClient.h
+++ b/features/FEATURE_BLE/targets/TARGET_CORDIO/CordioPalAttClient.h
@@ -22,6 +22,8 @@
 #include "ble/pal/SimpleAttServerMessage.h"
 #include "att_api.h"
 #include "att_defs.h"
+#include "ble/pal/PalGap.h"
+#include "CordioPalGap.h"
 
 namespace ble {
 namespace pal {
@@ -318,11 +320,20 @@ public:
      */
     static void att_client_handler(const attEvt_t* event)
     {
+        if (event->hdr.status == ATT_SUCCESS && event->hdr.event == ATT_MTU_UPDATE_IND) {
+            ble::pal::Gap::EventHandler *handler;
+            handler = ble::pal::vendor::cordio::Gap::get_gap().get_event_handler();
+            if (handler) {
+                handler->on_att_mtu_changed(event->hdr.param, event->mtu);
+            }
+            return;
+        }
+
         // all handlers are stored in a static array
         static const event_handler_t handlers[] = {
             &timeout_event_handler,
             &event_handler<ErrorResponseConverter>,
-            &event_handler<ExchangeMtuResponseConverter>,
+            //&event_handler<ExchangeMtuResponseConverter>,
             &event_handler<FindInformationResponseConverter>,
             &event_handler<FindByTypeValueResponseConverter>,
             &event_handler<ReadByTypeResponseConverter>,
diff --git a/features/FEATURE_BLE/targets/TARGET_CORDIO/source/CordioBLE.cpp b/features/FEATURE_BLE/targets/TARGET_CORDIO/source/CordioBLE.cpp
index ba57e6bb96..8be2da8092 100644
--- a/features/FEATURE_BLE/targets/TARGET_CORDIO/source/CordioBLE.cpp
+++ b/features/FEATURE_BLE/targets/TARGET_CORDIO/source/CordioBLE.cpp
@@ -286,6 +286,20 @@ void BLE::processEvents()
 
 void BLE::device_manager_cb(dmEvt_t* dm_event)
 {
+    if (dm_event->hdr.status == HCI_SUCCESS && dm_event->hdr.event == DM_CONN_DATA_LEN_CHANGE_IND) {
+        // this event can only happen after a connection has been established therefore gap is present
+        ble::pal::Gap::EventHandler *handler;
+        handler = ble::pal::vendor::cordio::Gap::get_gap().get_event_handler();
+        if (handler) {
+            handler->on_packet_paylod_size_changed(
+                dm_event->hdr.param,
+                dm_event->dataLenChange.maxTxOctets,
+                dm_event->dataLenChange.maxRxOctets
+            );
+        }
+        return;
+    }
+
     BLE::deviceInstance().stack_handler(0, &dm_event->hdr);
 }
 

From 06a2a403e959d58a749341496cc7810972f062d0 Mon Sep 17 00:00:00 2001
From: paul-szczepanek-arm
 <33840200+paul-szczepanek-arm@users.noreply.github.com>
Date: Wed, 9 Jan 2019 17:26:26 +0000
Subject: [PATCH 03/18] fix typos

---
 features/FEATURE_BLE/ble/gap/Gap.h                          | 2 +-
 features/FEATURE_BLE/ble/generic/GenericGap.h               | 6 +++---
 features/FEATURE_BLE/ble/pal/PalGap.h                       | 4 ++--
 features/FEATURE_BLE/source/generic/GenericGap.cpp          | 4 ++--
 .../FEATURE_BLE/targets/TARGET_CORDIO/source/CordioBLE.cpp  | 2 +-
 5 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/features/FEATURE_BLE/ble/gap/Gap.h b/features/FEATURE_BLE/ble/gap/Gap.h
index f859e49782..483293d39d 100644
--- a/features/FEATURE_BLE/ble/gap/Gap.h
+++ b/features/FEATURE_BLE/ble/gap/Gap.h
@@ -515,7 +515,7 @@ public:
          * @param txSize Number of octets we can send on this connection in a single packet.
          * @param rxSize Number of octets we can receive on this connection in a single packet.
          */
-        virtual void onPacketPaylodSizeChanged(
+        virtual void onPacketPayloadSizeChanged(
             connection_handle_t connectionHandle,
             uint16_t txSize,
             uint16_t rxSize
diff --git a/features/FEATURE_BLE/ble/generic/GenericGap.h b/features/FEATURE_BLE/ble/generic/GenericGap.h
index 2c8b686a0a..c620c1772b 100644
--- a/features/FEATURE_BLE/ble/generic/GenericGap.h
+++ b/features/FEATURE_BLE/ble/generic/GenericGap.h
@@ -628,12 +628,12 @@ private:
     );
 
     virtual void on_att_mtu_changed(
-        Handle_t connection_handle,
+        connection_handle_t connection_handle,
         uint16_t att_mtu_size
     );
 
-    virtual void on_packet_paylod_size_changed(
-        Handle_t connection_handle,
+    virtual void on_packet_payload_size_changed(
+        connection_handle_t connection_handle,
         uint16_t tx_size,
         uint16_t rx_size
     );
diff --git a/features/FEATURE_BLE/ble/pal/PalGap.h b/features/FEATURE_BLE/ble/pal/PalGap.h
index 5d0a16432d..6570ad6ebc 100644
--- a/features/FEATURE_BLE/ble/pal/PalGap.h
+++ b/features/FEATURE_BLE/ble/pal/PalGap.h
@@ -53,9 +53,9 @@ struct Gap {
         ) = 0;
 
         /**
-         * @copydoc Gap::EventHandler::onPacketPaylodSizeChanged
+         * @copydoc Gap::EventHandler::onPacketPayloadSizeChanged
          */
-        virtual void on_packet_paylod_size_changed(
+        virtual void on_packet_payload_size_changed(
             connection_handle_t connection_handle,
             uint16_t tx_size,
             uint16_t rx_size
diff --git a/features/FEATURE_BLE/source/generic/GenericGap.cpp b/features/FEATURE_BLE/source/generic/GenericGap.cpp
index 72959127d7..90212423c9 100644
--- a/features/FEATURE_BLE/source/generic/GenericGap.cpp
+++ b/features/FEATURE_BLE/source/generic/GenericGap.cpp
@@ -870,14 +870,14 @@ void GenericGap::on_att_mtu_changed(
     }
 }
 
-void GenericGap::on_packet_paylod_size_changed(
+void GenericGap::on_packet_payload_size_changed(
     Handle_t connection_handle,
     uint16_t tx_size,
     uint16_t rx_size
 )
 {
     if (_eventHandler) {
-        _eventHandler->onPacketPaylodSizeChanged(connection_handle, tx_size, rx_size);
+        _eventHandler->onPacketPayloadSizeChanged(connection_handle, tx_size, rx_size);
     }
 }
 
diff --git a/features/FEATURE_BLE/targets/TARGET_CORDIO/source/CordioBLE.cpp b/features/FEATURE_BLE/targets/TARGET_CORDIO/source/CordioBLE.cpp
index 8be2da8092..051c0b1a13 100644
--- a/features/FEATURE_BLE/targets/TARGET_CORDIO/source/CordioBLE.cpp
+++ b/features/FEATURE_BLE/targets/TARGET_CORDIO/source/CordioBLE.cpp
@@ -291,7 +291,7 @@ void BLE::device_manager_cb(dmEvt_t* dm_event)
         ble::pal::Gap::EventHandler *handler;
         handler = ble::pal::vendor::cordio::Gap::get_gap().get_event_handler();
         if (handler) {
-            handler->on_packet_paylod_size_changed(
+            handler->on_packet_payload_size_changed(
                 dm_event->hdr.param,
                 dm_event->dataLenChange.maxTxOctets,
                 dm_event->dataLenChange.maxRxOctets

From 21ad886e9eb6a2f3d270d94ed2c8e3166a9b2ffe Mon Sep 17 00:00:00 2001
From: paul-szczepanek-arm
 <33840200+paul-szczepanek-arm@users.noreply.github.com>
Date: Tue, 15 Jan 2019 13:25:19 +0000
Subject: [PATCH 04/18] handle mtu and data len events for softdevice

---
 .../TARGET_NRF52/source/btle/btle.cpp         | 53 ++++++++++++++++---
 1 file changed, 47 insertions(+), 6 deletions(-)

diff --git a/features/FEATURE_BLE/targets/TARGET_NORDIC/TARGET_NORDIC_SOFTDEVICE/TARGET_NRF52/source/btle/btle.cpp b/features/FEATURE_BLE/targets/TARGET_NORDIC/TARGET_NORDIC_SOFTDEVICE/TARGET_NRF52/source/btle/btle.cpp
index 962ddef9b7..1f74a7115f 100644
--- a/features/FEATURE_BLE/targets/TARGET_NORDIC/TARGET_NORDIC_SOFTDEVICE/TARGET_NRF52/source/btle/btle.cpp
+++ b/features/FEATURE_BLE/targets/TARGET_NORDIC/TARGET_NORDIC_SOFTDEVICE/TARGET_NRF52/source/btle/btle.cpp
@@ -26,6 +26,7 @@
 
 #include "ble/GapEvents.h"
 #include "nRF5xn.h"
+#include <algorithm>
 
 #ifdef S110
     #define IS_LEGACY_DEVICE_MANAGER_ENABLED 1
@@ -368,15 +369,55 @@ void btle_handler(const ble_evt_t *p_ble_evt)
 
             ASSERT_STATUS_RET_VOID(sd_ble_gap_data_length_update(p_gap_evt->conn_handle, &dlp, NULL));
         		break;
+        // Handle Data length negotiation result
+        case BLE_GAP_EVT_DATA_LENGTH_UPDATE: {
+            /* inform user application */
+            if (gap._eventHandler) {
+                Gap::Handle_t connection = p_ble_evt->evt.gap_evt.conn_handle;
+                const ble_gap_evt_data_length_update_t &update =
+                    p_ble_evt->evt.gap_evt.params.data_length_update;
+
+                gap._eventHandler->onPacketPayloadSizeChanged(
+                    connection,
+                    update.effective_params.max_tx_octets,
+                    update.effective_params.max_rx_octets
+                );
+            }
+            break;
         }
 
-        	// Handle MTU exchange request
-        case BLE_GATTS_EVT_EXCHANGE_MTU_REQUEST:
-        {
-        		// Respond with the server MTU
-            uint16_t   conn_handle = p_ble_evt->evt.gatts_evt.conn_handle;
+        case BLE_GATTS_EVT_EXCHANGE_MTU_REQUEST: {
+            /* Respond with the server MTU */
+            uint16_t conn_handle = p_ble_evt->evt.gatts_evt.conn_handle;
             ASSERT_STATUS_RET_VOID(sd_ble_gatts_exchange_mtu_reply(conn_handle, NRF_SDH_BLE_GATT_MAX_MTU_SIZE));
-        		break;
+
+            /* inform user application */
+            if (gap._eventHandler) {
+                Gap::Handle_t connection = p_ble_evt->evt.gap_evt.conn_handle;
+                const ble_gatts_evt_exchange_mtu_request_t &update =
+                    p_ble_evt->evt.gatts_evt.params.exchange_mtu_request;
+
+                gap._eventHandler->onAttMtuChanged(
+                    connection,
+                    std::min(NRF_SDH_BLE_GATT_MAX_MTU_SIZE, (int)(update.client_rx_mtu))
+                );
+            }
+            break;
+        }
+
+        case BLE_GATTC_EVT_EXCHANGE_MTU_RSP: {
+            /* inform user application */
+            if (gap._eventHandler) {
+                Gap::Handle_t connection = p_ble_evt->evt.gap_evt.conn_handle;
+                const ble_gattc_evt_exchange_mtu_rsp_t &update =
+                    p_ble_evt->evt.gattc_evt.params.exchange_mtu_rsp;
+
+                gap._eventHandler->onAttMtuChanged(
+                    connection,
+                    std::min(NRF_SDH_BLE_GATT_MAX_MTU_SIZE, (int)(update.server_rx_mtu))
+                );
+            }
+            break;
         }
 #endif
         case BLE_GAP_EVT_CONN_PARAM_UPDATE_REQUEST: {

From 356ec39d02967af4fcb6331fb53e2e3f2ae49191 Mon Sep 17 00:00:00 2001
From: paul-szczepanek-arm
 <33840200+paul-szczepanek-arm@users.noreply.github.com>
Date: Tue, 15 Jan 2019 13:25:31 +0000
Subject: [PATCH 05/18] fix style

---
 .../TARGET_NRF52/source/btle/btle.cpp         | 23 +++++++++++--------
 1 file changed, 13 insertions(+), 10 deletions(-)

diff --git a/features/FEATURE_BLE/targets/TARGET_NORDIC/TARGET_NORDIC_SOFTDEVICE/TARGET_NRF52/source/btle/btle.cpp b/features/FEATURE_BLE/targets/TARGET_NORDIC/TARGET_NORDIC_SOFTDEVICE/TARGET_NRF52/source/btle/btle.cpp
index 1f74a7115f..c3fa48b81c 100644
--- a/features/FEATURE_BLE/targets/TARGET_NORDIC/TARGET_NORDIC_SOFTDEVICE/TARGET_NRF52/source/btle/btle.cpp
+++ b/features/FEATURE_BLE/targets/TARGET_NORDIC/TARGET_NORDIC_SOFTDEVICE/TARGET_NRF52/source/btle/btle.cpp
@@ -335,26 +335,27 @@ void btle_handler(const ble_evt_t *p_ble_evt)
 #if  (NRF_SD_BLE_API_VERSION >= 5)
 #ifndef S140
         // Handle PHY upgrade request
-        case BLE_GAP_EVT_PHY_UPDATE_REQUEST:
+        case BLE_GAP_EVT_PHY_UPDATE_REQUEST: {
             gap.on_phy_update_request(
                 p_ble_evt->evt.gap_evt.conn_handle,
                 p_ble_evt->evt.gap_evt.params.phy_update_request
             );
             break;
+        }
 #endif
-        case BLE_GAP_EVT_PHY_UPDATE:
+        case BLE_GAP_EVT_PHY_UPDATE: {
             gap.on_phy_update(
                 p_ble_evt->evt.gap_evt.conn_handle,
                 p_ble_evt->evt.gap_evt.params.phy_update
             );
             break;
+        }
 
-        	// Handle Data length negotiation request
-        case BLE_GAP_EVT_DATA_LENGTH_UPDATE_REQUEST:
-        {
-            ble_gap_evt_t       const * p_gap_evt = &p_ble_evt->evt.gap_evt;
+        // Handle Data length negotiation request
+        case BLE_GAP_EVT_DATA_LENGTH_UPDATE_REQUEST: {
+            ble_gap_evt_t const * p_gap_evt = &p_ble_evt->evt.gap_evt;
             uint8_t const data_length_peer =
-                p_gap_evt->params.data_length_update_request.peer_params.max_tx_octets;
+            p_gap_evt->params.data_length_update_request.peer_params.max_tx_octets;
 
             uint8_t const data_length = MIN(
                 NRF_SDH_BLE_GATT_MAX_MTU_SIZE + 4 /* L2CAP header size */,
@@ -363,12 +364,14 @@ void btle_handler(const ble_evt_t *p_ble_evt)
 
             ble_gap_data_length_params_t const dlp =
             {
-                /* max_rx_octets */ data_length,
-                /* max_tx_octets */ data_length
+                /* max_rx_octets */data_length,
+                /* max_tx_octets */data_length
             };
 
             ASSERT_STATUS_RET_VOID(sd_ble_gap_data_length_update(p_gap_evt->conn_handle, &dlp, NULL));
-        		break;
+            break;
+        }
+
         // Handle Data length negotiation result
         case BLE_GAP_EVT_DATA_LENGTH_UPDATE: {
             /* inform user application */

From b6df6d54a1266af41ceba4d6bab1a502d9d56465 Mon Sep 17 00:00:00 2001
From: paul-szczepanek-arm
 <33840200+paul-szczepanek-arm@users.noreply.github.com>
Date: Tue, 15 Jan 2019 14:26:30 +0000
Subject: [PATCH 06/18] change event names

---
 features/FEATURE_BLE/ble/gap/Gap.h                     | 10 +++++++---
 features/FEATURE_BLE/ble/generic/GenericGap.h          |  2 +-
 features/FEATURE_BLE/ble/pal/PalGap.h                  |  6 +++---
 features/FEATURE_BLE/source/generic/GenericGap.cpp     |  6 +++---
 .../targets/TARGET_CORDIO/source/CordioBLE.cpp         |  2 +-
 .../TARGET_NRF52/source/btle/btle.cpp                  |  6 +++---
 6 files changed, 18 insertions(+), 14 deletions(-)

diff --git a/features/FEATURE_BLE/ble/gap/Gap.h b/features/FEATURE_BLE/ble/gap/Gap.h
index 483293d39d..54d71e0bc0 100644
--- a/features/FEATURE_BLE/ble/gap/Gap.h
+++ b/features/FEATURE_BLE/ble/gap/Gap.h
@@ -500,7 +500,7 @@ public:
          * @param connectionHandle The handle of the connection that changed the size.
          * @param attMtuSize
          */
-        virtual void onAttMtuChanged(
+        virtual void onAttMtuChange(
             connection_handle_t connectionHandle,
             uint16_t attMtuSize
         )
@@ -509,13 +509,17 @@ public:
 
         /**
          * Function invoked when the connections changes the maximum number of octets
-         * that can be sent or received by the controller in a single packet.
+         * that can be sent or received by the controller in a single packet. A single
+         * L2CAP packet can be fragmented across many such packets.
+         *
+         * @note This only triggers if controller supports data length extension and
+         * negotiated data length is longer than the default 23.
          *
          * @param connectionHandle The handle of the connection that changed the size.
          * @param txSize Number of octets we can send on this connection in a single packet.
          * @param rxSize Number of octets we can receive on this connection in a single packet.
          */
-        virtual void onPacketPayloadSizeChanged(
+        virtual void onDataLengthChange(
             connection_handle_t connectionHandle,
             uint16_t txSize,
             uint16_t rxSize
diff --git a/features/FEATURE_BLE/ble/generic/GenericGap.h b/features/FEATURE_BLE/ble/generic/GenericGap.h
index c620c1772b..f00489a5c0 100644
--- a/features/FEATURE_BLE/ble/generic/GenericGap.h
+++ b/features/FEATURE_BLE/ble/generic/GenericGap.h
@@ -632,7 +632,7 @@ private:
         uint16_t att_mtu_size
     );
 
-    virtual void on_packet_payload_size_changed(
+    virtual void on_data_length_change(
         connection_handle_t connection_handle,
         uint16_t tx_size,
         uint16_t rx_size
diff --git a/features/FEATURE_BLE/ble/pal/PalGap.h b/features/FEATURE_BLE/ble/pal/PalGap.h
index 6570ad6ebc..d4cea30243 100644
--- a/features/FEATURE_BLE/ble/pal/PalGap.h
+++ b/features/FEATURE_BLE/ble/pal/PalGap.h
@@ -45,7 +45,7 @@ struct Gap {
         ) = 0;
 
         /**
-         * @copydoc Gap::EventHandler::onAttMtuChanged
+         * @copydoc Gap::EventHandler::onAttMtuChange
          */
         virtual void on_att_mtu_changed(
             connection_handle_t connection_handle,
@@ -53,9 +53,9 @@ struct Gap {
         ) = 0;
 
         /**
-         * @copydoc Gap::EventHandler::onPacketPayloadSizeChanged
+         * @copydoc Gap::EventHandler::onDataLengthChange
          */
-        virtual void on_packet_payload_size_changed(
+        virtual void on_data_length_change(
             connection_handle_t connection_handle,
             uint16_t tx_size,
             uint16_t rx_size
diff --git a/features/FEATURE_BLE/source/generic/GenericGap.cpp b/features/FEATURE_BLE/source/generic/GenericGap.cpp
index 90212423c9..321ee6e4a6 100644
--- a/features/FEATURE_BLE/source/generic/GenericGap.cpp
+++ b/features/FEATURE_BLE/source/generic/GenericGap.cpp
@@ -866,18 +866,18 @@ void GenericGap::on_att_mtu_changed(
 )
 {
     if (_eventHandler) {
-        _eventHandler->onAttMtuChanged(connection_handle, att_mtu_size);
+        _eventHandler->onAttMtuChange(connection_handle, att_mtu_size);
     }
 }
 
-void GenericGap::on_packet_payload_size_changed(
+void GenericGap::on_data_length_change(
     Handle_t connection_handle,
     uint16_t tx_size,
     uint16_t rx_size
 )
 {
     if (_eventHandler) {
-        _eventHandler->onPacketPayloadSizeChanged(connection_handle, tx_size, rx_size);
+        _eventHandler->onDataLengthChange(connection_handle, tx_size, rx_size);
     }
 }
 
diff --git a/features/FEATURE_BLE/targets/TARGET_CORDIO/source/CordioBLE.cpp b/features/FEATURE_BLE/targets/TARGET_CORDIO/source/CordioBLE.cpp
index 051c0b1a13..5cffdac74b 100644
--- a/features/FEATURE_BLE/targets/TARGET_CORDIO/source/CordioBLE.cpp
+++ b/features/FEATURE_BLE/targets/TARGET_CORDIO/source/CordioBLE.cpp
@@ -291,7 +291,7 @@ void BLE::device_manager_cb(dmEvt_t* dm_event)
         ble::pal::Gap::EventHandler *handler;
         handler = ble::pal::vendor::cordio::Gap::get_gap().get_event_handler();
         if (handler) {
-            handler->on_packet_payload_size_changed(
+            handler->on_data_length_change(
                 dm_event->hdr.param,
                 dm_event->dataLenChange.maxTxOctets,
                 dm_event->dataLenChange.maxRxOctets
diff --git a/features/FEATURE_BLE/targets/TARGET_NORDIC/TARGET_NORDIC_SOFTDEVICE/TARGET_NRF52/source/btle/btle.cpp b/features/FEATURE_BLE/targets/TARGET_NORDIC/TARGET_NORDIC_SOFTDEVICE/TARGET_NRF52/source/btle/btle.cpp
index c3fa48b81c..7e7e4258f5 100644
--- a/features/FEATURE_BLE/targets/TARGET_NORDIC/TARGET_NORDIC_SOFTDEVICE/TARGET_NRF52/source/btle/btle.cpp
+++ b/features/FEATURE_BLE/targets/TARGET_NORDIC/TARGET_NORDIC_SOFTDEVICE/TARGET_NRF52/source/btle/btle.cpp
@@ -380,7 +380,7 @@ void btle_handler(const ble_evt_t *p_ble_evt)
                 const ble_gap_evt_data_length_update_t &update =
                     p_ble_evt->evt.gap_evt.params.data_length_update;
 
-                gap._eventHandler->onPacketPayloadSizeChanged(
+                gap._eventHandler->onDataLengthChange(
                     connection,
                     update.effective_params.max_tx_octets,
                     update.effective_params.max_rx_octets
@@ -400,7 +400,7 @@ void btle_handler(const ble_evt_t *p_ble_evt)
                 const ble_gatts_evt_exchange_mtu_request_t &update =
                     p_ble_evt->evt.gatts_evt.params.exchange_mtu_request;
 
-                gap._eventHandler->onAttMtuChanged(
+                gap._eventHandler->onAttMtuChange(
                     connection,
                     std::min(NRF_SDH_BLE_GATT_MAX_MTU_SIZE, (int)(update.client_rx_mtu))
                 );
@@ -415,7 +415,7 @@ void btle_handler(const ble_evt_t *p_ble_evt)
                 const ble_gattc_evt_exchange_mtu_rsp_t &update =
                     p_ble_evt->evt.gattc_evt.params.exchange_mtu_rsp;
 
-                gap._eventHandler->onAttMtuChanged(
+                gap._eventHandler->onAttMtuChange(
                     connection,
                     std::min(NRF_SDH_BLE_GATT_MAX_MTU_SIZE, (int)(update.server_rx_mtu))
                 );

From 02d5391cd01755e4da2c4381484beb9325020ebd Mon Sep 17 00:00:00 2001
From: paul-szczepanek-arm
 <33840200+paul-szczepanek-arm@users.noreply.github.com>
Date: Wed, 16 Jan 2019 14:23:28 +0000
Subject: [PATCH 07/18] fix possible truncation

---
 .../TARGET_NRF52/source/btle/btle.cpp                        | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/features/FEATURE_BLE/targets/TARGET_NORDIC/TARGET_NORDIC_SOFTDEVICE/TARGET_NRF52/source/btle/btle.cpp b/features/FEATURE_BLE/targets/TARGET_NORDIC/TARGET_NORDIC_SOFTDEVICE/TARGET_NRF52/source/btle/btle.cpp
index 7e7e4258f5..57cb8ef3f8 100644
--- a/features/FEATURE_BLE/targets/TARGET_NORDIC/TARGET_NORDIC_SOFTDEVICE/TARGET_NRF52/source/btle/btle.cpp
+++ b/features/FEATURE_BLE/targets/TARGET_NORDIC/TARGET_NORDIC_SOFTDEVICE/TARGET_NRF52/source/btle/btle.cpp
@@ -355,15 +355,14 @@ void btle_handler(const ble_evt_t *p_ble_evt)
         case BLE_GAP_EVT_DATA_LENGTH_UPDATE_REQUEST: {
             ble_gap_evt_t const * p_gap_evt = &p_ble_evt->evt.gap_evt;
             uint8_t const data_length_peer =
-            p_gap_evt->params.data_length_update_request.peer_params.max_tx_octets;
+                p_gap_evt->params.data_length_update_request.peer_params.max_tx_octets;
 
             uint8_t const data_length = MIN(
                 NRF_SDH_BLE_GATT_MAX_MTU_SIZE + 4 /* L2CAP header size */,
                 data_length_peer
             );
 
-            ble_gap_data_length_params_t const dlp =
-            {
+            ble_gap_data_length_params_t const dlp = {
                 /* max_rx_octets */data_length,
                 /* max_tx_octets */data_length
             };

From c10fc2eb8ed2b303cfa5775934dd517ba87c3e79 Mon Sep 17 00:00:00 2001
From: paul-szczepanek-arm
 <33840200+paul-szczepanek-arm@users.noreply.github.com>
Date: Wed, 16 Jan 2019 16:55:50 +0000
Subject: [PATCH 08/18] add API to trigger MTU negotiation

---
 features/FEATURE_BLE/ble/GattClient.h         | 21 +++++++++++++++++++
 .../ble/generic/GenericGattClient.h           |  7 +++++++
 .../source/generic/GenericGattClient.cpp      |  6 ++++++
 3 files changed, 34 insertions(+)

diff --git a/features/FEATURE_BLE/ble/GattClient.h b/features/FEATURE_BLE/ble/GattClient.h
index fc60e5c840..71ac437170 100644
--- a/features/FEATURE_BLE/ble/GattClient.h
+++ b/features/FEATURE_BLE/ble/GattClient.h
@@ -635,6 +635,27 @@ public:
         (void) characteristic;
     }
 
+    /**
+     * Trigger MTU negotiation. This might result in a Gap event onAttMtuChange
+     * being called if MTU changes.
+     *
+     * @note This does not guarantee a change in MTU size. If size remains
+     * unchanged no event will be generated.
+     *
+     * @param connection Connection on which the MTU is to be negotiated.
+     *
+     * @return BLE_ERROR_NONE if the procedure has been launched successfully
+     * otherwise an appropriate error.
+     */
+    virtual ble_error_t negotiateAttMtu(
+        Gap::Handle_t connection
+    ) {
+        /* Requesting action from porter(s): override this API if this
+           capability is supported. */
+        (void) connection;
+        return BLE_ERROR_NOT_IMPLEMENTED;
+    }
+
     /**
      * Register an handler for Handle Value Notification/Indication events.
      *
diff --git a/features/FEATURE_BLE/ble/generic/GenericGattClient.h b/features/FEATURE_BLE/ble/generic/GenericGattClient.h
index b135535d93..c4e0049adc 100644
--- a/features/FEATURE_BLE/ble/generic/GenericGattClient.h
+++ b/features/FEATURE_BLE/ble/generic/GenericGattClient.h
@@ -111,6 +111,13 @@ public:
         const DiscoveredCharacteristic& characteristic
     );
 
+    /**
+     * @see GattClient::negotiateAttMtu
+     */
+    virtual ble_error_t negotiateAttMtu(
+        connection_handle_t connection
+    );
+
 	/**
 	 * @see GattClient::reset
 	 */
diff --git a/features/FEATURE_BLE/source/generic/GenericGattClient.cpp b/features/FEATURE_BLE/source/generic/GenericGattClient.cpp
index c89577d988..2036ec6f77 100644
--- a/features/FEATURE_BLE/source/generic/GenericGattClient.cpp
+++ b/features/FEATURE_BLE/source/generic/GenericGattClient.cpp
@@ -1259,6 +1259,12 @@ void GenericGattClient::terminateCharacteristicDescriptorDiscovery(
 
 }
 
+ble_error_t GenericGattClient::negotiateAttMtu(
+    connection_handle_t connection
+) {
+    return _pal_client->exchange_mtu(connection);
+}
+
 ble_error_t GenericGattClient::reset(void) {
 
 	// _is_reseting prevent executions of new procedure while the instance resets.

From a3f635eb8826426d93a34f69f0fa0397d14e5199 Mon Sep 17 00:00:00 2001
From: paul-szczepanek-arm
 <33840200+paul-szczepanek-arm@users.noreply.github.com>
Date: Wed, 30 Jan 2019 10:50:25 +0000
Subject: [PATCH 09/18] fix type name

---
 features/FEATURE_BLE/ble/GattClient.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/features/FEATURE_BLE/ble/GattClient.h b/features/FEATURE_BLE/ble/GattClient.h
index 71ac437170..a429b6c94e 100644
--- a/features/FEATURE_BLE/ble/GattClient.h
+++ b/features/FEATURE_BLE/ble/GattClient.h
@@ -648,7 +648,7 @@ public:
      * otherwise an appropriate error.
      */
     virtual ble_error_t negotiateAttMtu(
-        Gap::Handle_t connection
+        ble::connection_handle_t connection
     ) {
         /* Requesting action from porter(s): override this API if this
            capability is supported. */

From b6282852543090fc2af724c3d626bf160e01de33 Mon Sep 17 00:00:00 2001
From: paul-szczepanek-arm
 <33840200+paul-szczepanek-arm@users.noreply.github.com>
Date: Fri, 1 Feb 2019 19:29:48 +0000
Subject: [PATCH 10/18] route mtu changed events to server and client instead
 of gap

---
 features/FEATURE_BLE/ble/GattClient.h         | 37 ++++++++++
 features/FEATURE_BLE/ble/GattServer.h         | 37 ++++++++++
 features/FEATURE_BLE/ble/gap/Gap.h            | 15 ----
 features/FEATURE_BLE/ble/generic/GenericGap.h |  5 --
 .../ble/generic/GenericGattClient.h           | 18 ++++-
 features/FEATURE_BLE/ble/pal/PalGap.h         |  8 --
 features/FEATURE_BLE/ble/pal/PalGattClient.h  | 21 +++++-
 .../FEATURE_BLE/source/generic/GenericGap.cpp | 10 ---
 .../source/generic/GenericGattClient.cpp      |  2 +-
 .../targets/TARGET_CORDIO/CordioGattServer.h  |  4 +
 .../TARGET_CORDIO/CordioPalAttClient.cpp      | 73 +++++++++++++++++++
 .../TARGET_CORDIO/CordioPalAttClient.h        | 50 +------------
 .../TARGET_CORDIO/source/CordioGattServer.cpp |  7 +-
 .../source/nRF5xGattServer.h                  |  3 +
 .../TARGET_NRF51/source/nRF5xGattServer.h     |  3 +
 .../TARGET_NRF52/source/btle/btle.cpp         |  6 +-
 .../TARGET_NRF52/source/nRF5xGattServer.h     |  3 +
 17 files changed, 211 insertions(+), 91 deletions(-)
 create mode 100644 features/FEATURE_BLE/targets/TARGET_CORDIO/CordioPalAttClient.cpp

diff --git a/features/FEATURE_BLE/ble/GattClient.h b/features/FEATURE_BLE/ble/GattClient.h
index a429b6c94e..5eff0df04e 100644
--- a/features/FEATURE_BLE/ble/GattClient.h
+++ b/features/FEATURE_BLE/ble/GattClient.h
@@ -83,6 +83,38 @@
  */
 class GattClient {
 public:
+
+    /**
+     * Definition of the general handler of GattClient related events.
+     */
+    struct EventHandler {
+        /**
+         * Function invoked when the connections changes the ATT_MTU which controls
+         * the maximum size of an attribute that can be read in a single L2CAP packet
+         * which might be fragmented across multiple packets.
+         *
+         * @param connectionHandle The handle of the connection that changed the size.
+         * @param attMtuSize
+         */
+        virtual void onAttMtuChange(
+            ble::connection_handle_t connectionHandle,
+            uint16_t attMtuSize
+        )
+        {
+        }
+    };
+
+    /**
+     * Assign the event handler implementation that will be used by the
+     * module to signal events back to the application.
+     *
+     * @param handler Application implementation of an EventHandler.
+     */
+    void setEventHandler(EventHandler *handler)
+    {
+        _eventHandler = handler;
+    }
+
     /**
      * Attribute read event handler.
      *
@@ -815,6 +847,11 @@ public:
     }
 
 protected:
+    /**
+     * Event handler provided by the application.
+     */
+    EventHandler *_eventHandler;
+
     /**
      * Callchain containing all registered event handlers for data read
      * events.
diff --git a/features/FEATURE_BLE/ble/GattServer.h b/features/FEATURE_BLE/ble/GattServer.h
index 3b0d140392..8335e7f798 100644
--- a/features/FEATURE_BLE/ble/GattServer.h
+++ b/features/FEATURE_BLE/ble/GattServer.h
@@ -87,6 +87,38 @@
  */
 class GattServer {
 public:
+
+    /**
+     * Definition of the general handler of GattServer related events.
+     */
+    struct EventHandler {
+        /**
+         * Function invoked when the connections changes the ATT_MTU which controls
+         * the maximum size of an attribute that can be read in a single L2CAP packet
+         * which might be fragmented across multiple packets.
+         *
+         * @param connectionHandle The handle of the connection that changed the size.
+         * @param attMtuSize
+         */
+        virtual void onAttMtuChange(
+            ble::connection_handle_t connectionHandle,
+            uint16_t attMtuSize
+        )
+        {
+        }
+    };
+
+    /**
+     * Assign the event handler implementation that will be used by the
+     * module to signal events back to the application.
+     *
+     * @param handler Application implementation of an EventHandler.
+     */
+    void setEventHandler(EventHandler *handler)
+    {
+        _eventHandler = handler;
+    }
+
     /**
      * Event handler invoked when the server has sent data to a client.
      *
@@ -778,6 +810,11 @@ public:
     }
 
 protected:
+    /**
+     * Event handler provided by the application.
+     */
+    EventHandler *_eventHandler;
+
     /**
      * The total number of services added to the ATT table.
      */
diff --git a/features/FEATURE_BLE/ble/gap/Gap.h b/features/FEATURE_BLE/ble/gap/Gap.h
index 54d71e0bc0..93d1957709 100644
--- a/features/FEATURE_BLE/ble/gap/Gap.h
+++ b/features/FEATURE_BLE/ble/gap/Gap.h
@@ -492,21 +492,6 @@ public:
         {
         }
 
-        /**
-         * Function invoked when the connections changes the ATT_MTU which controls
-         * the maximum size of an attribute that can be read in a single L2CAP packet
-         * which might be fragmented across multiple packets.
-         *
-         * @param connectionHandle The handle of the connection that changed the size.
-         * @param attMtuSize
-         */
-        virtual void onAttMtuChange(
-            connection_handle_t connectionHandle,
-            uint16_t attMtuSize
-        )
-        {
-        }
-
         /**
          * Function invoked when the connections changes the maximum number of octets
          * that can be sent or received by the controller in a single packet. A single
diff --git a/features/FEATURE_BLE/ble/generic/GenericGap.h b/features/FEATURE_BLE/ble/generic/GenericGap.h
index f00489a5c0..be0903edc1 100644
--- a/features/FEATURE_BLE/ble/generic/GenericGap.h
+++ b/features/FEATURE_BLE/ble/generic/GenericGap.h
@@ -627,11 +627,6 @@ private:
         phy_t rx_phy
     );
 
-    virtual void on_att_mtu_changed(
-        connection_handle_t connection_handle,
-        uint16_t att_mtu_size
-    );
-
     virtual void on_data_length_change(
         connection_handle_t connection_handle,
         uint16_t tx_size,
diff --git a/features/FEATURE_BLE/ble/generic/GenericGattClient.h b/features/FEATURE_BLE/ble/generic/GenericGattClient.h
index c4e0049adc..eece4dfed4 100644
--- a/features/FEATURE_BLE/ble/generic/GenericGattClient.h
+++ b/features/FEATURE_BLE/ble/generic/GenericGattClient.h
@@ -33,8 +33,20 @@ namespace generic {
  * @attention: Not part of the public interface of BLE API.
  */
 class GenericGattClient : public GattClient,
-                          public pal::SigningEventMonitor {
+                          public pal::SigningEventMonitor,
+                          public pal::GattClient::EventHandler {
 public:
+
+    virtual void on_att_mtu_change(
+        ble::connection_handle_t connection_handle,
+        uint16_t att_mtu_size
+    )
+    {
+        if (_eventHandler) {
+            _eventHandler->onAttMtuChange(connection_handle, att_mtu_size);
+        }
+    }
+
     /**
      * Create a GenericGattClient from a pal::GattClient
      */
@@ -128,6 +140,10 @@ public:
      */
     virtual void set_signing_event_handler(pal::SigningEventMonitor::EventHandler *signing_event_handler);
 
+    ::GattClient::EventHandler* getEventHandler() {
+        return _eventHandler;
+    }
+
 private:
     struct ProcedureControlBlock;
     struct DiscoveryControlBlock;
diff --git a/features/FEATURE_BLE/ble/pal/PalGap.h b/features/FEATURE_BLE/ble/pal/PalGap.h
index d4cea30243..3598fdace2 100644
--- a/features/FEATURE_BLE/ble/pal/PalGap.h
+++ b/features/FEATURE_BLE/ble/pal/PalGap.h
@@ -44,14 +44,6 @@ struct Gap {
             ble::phy_t rx_phy
         ) = 0;
 
-        /**
-         * @copydoc Gap::EventHandler::onAttMtuChange
-         */
-        virtual void on_att_mtu_changed(
-            connection_handle_t connection_handle,
-            uint16_t att_mtu_size
-        ) = 0;
-
         /**
          * @copydoc Gap::EventHandler::onDataLengthChange
          */
diff --git a/features/FEATURE_BLE/ble/pal/PalGattClient.h b/features/FEATURE_BLE/ble/pal/PalGattClient.h
index 2152c428f4..d0362240e5 100644
--- a/features/FEATURE_BLE/ble/pal/PalGattClient.h
+++ b/features/FEATURE_BLE/ble/pal/PalGattClient.h
@@ -55,8 +55,27 @@ namespace pal {
  * the class AttClientToGattClientAdapter
  */
 class GattClient {
-
 public:
+    /**
+     * Definition of the general handler of GattClient related events.
+     */
+    struct EventHandler {
+        /**
+         * Function invoked when the connections changes the ATT_MTU which controls
+         * the maximum size of an attribute that can be read in a single L2CAP packet
+         * which might be fragmented across multiple packets.
+         *
+         * @param connectionHandle The handle of the connection that changed the size.
+         * @param attMtuSize
+         */
+        virtual void on_att_mtu_change(
+            ble::connection_handle_t connection_handle,
+            uint16_t att_mtu_size
+        )
+        {
+        }
+    };
+
     /**
      * Initialisation of the instance. An implementation can use this function
      * to initialise the subsystems needed to realize the operations of this
diff --git a/features/FEATURE_BLE/source/generic/GenericGap.cpp b/features/FEATURE_BLE/source/generic/GenericGap.cpp
index 321ee6e4a6..26a1cbcb01 100644
--- a/features/FEATURE_BLE/source/generic/GenericGap.cpp
+++ b/features/FEATURE_BLE/source/generic/GenericGap.cpp
@@ -860,16 +860,6 @@ void GenericGap::on_read_phy(
     }
 }
 
-void GenericGap::on_att_mtu_changed(
-    Handle_t connection_handle,
-    uint16_t att_mtu_size
-)
-{
-    if (_eventHandler) {
-        _eventHandler->onAttMtuChange(connection_handle, att_mtu_size);
-    }
-}
-
 void GenericGap::on_data_length_change(
     Handle_t connection_handle,
     uint16_t tx_size,
diff --git a/features/FEATURE_BLE/source/generic/GenericGattClient.cpp b/features/FEATURE_BLE/source/generic/GenericGattClient.cpp
index 2036ec6f77..4ca3616fff 100644
--- a/features/FEATURE_BLE/source/generic/GenericGattClient.cpp
+++ b/features/FEATURE_BLE/source/generic/GenericGattClient.cpp
@@ -1280,7 +1280,7 @@ ble_error_t GenericGattClient::reset(void) {
 }
 
 void GenericGattClient::set_signing_event_handler(
-    EventHandler *signing_event_handler
+    pal::SigningEventMonitor::EventHandler *signing_event_handler
 ) {
     _signing_event_handler = signing_event_handler;
 }
diff --git a/features/FEATURE_BLE/targets/TARGET_CORDIO/CordioGattServer.h b/features/FEATURE_BLE/targets/TARGET_CORDIO/CordioGattServer.h
index bb9da0dbe5..84dc2dbdf0 100644
--- a/features/FEATURE_BLE/targets/TARGET_CORDIO/CordioGattServer.h
+++ b/features/FEATURE_BLE/targets/TARGET_CORDIO/CordioGattServer.h
@@ -62,6 +62,10 @@ public:
      */
     static GattServer &getInstance();
 
+    ::GattServer::EventHandler* getEventHandler() {
+        return _eventHandler;
+    }
+
     /**
      * Initialize the GattServer and add mandatory services (generic access and
      * generic attribute service).
diff --git a/features/FEATURE_BLE/targets/TARGET_CORDIO/CordioPalAttClient.cpp b/features/FEATURE_BLE/targets/TARGET_CORDIO/CordioPalAttClient.cpp
new file mode 100644
index 0000000000..37b6373d43
--- /dev/null
+++ b/features/FEATURE_BLE/targets/TARGET_CORDIO/CordioPalAttClient.cpp
@@ -0,0 +1,73 @@
+/* mbed Microcontroller Library
+ * Copyright (c) 2019 ARM Limited
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "CordioPalAttClient.h"
+#include "CordioBLE.h"
+
+namespace ble {
+namespace pal {
+namespace vendor {
+namespace cordio {
+
+void CordioAttClient::att_client_handler(const attEvt_t* event)
+{
+    if (event->hdr.status == ATT_SUCCESS && event->hdr.event == ATT_MTU_UPDATE_IND) {
+        ble::vendor::cordio::BLE& ble = ble::vendor::cordio::BLE::deviceInstance();
+        ble::pal::GattClient::EventHandler &handler = ble.getGattClient();
+        handler.on_att_mtu_change(event->hdr.param, event->mtu);
+    } else {
+        // all handlers are stored in a static array
+        static const event_handler_t handlers[] = {
+            &timeout_event_handler,
+            &event_handler<ErrorResponseConverter>,
+            //&event_handler<ExchangeMtuResponseConverter>,
+            &event_handler<FindInformationResponseConverter>,
+            &event_handler<FindByTypeValueResponseConverter>,
+            &event_handler<ReadByTypeResponseConverter>,
+            &event_handler<ReadResponseConverter>,
+            &event_handler<ReadBlobResponseConverter>,
+            &event_handler<ReadMultipleResponseConverter>,
+            &event_handler<ReadBygroupTypeResponseConverter>,
+            &event_handler<WriteResponseConverter>,
+            &event_handler<PrepareWriteResponseConverter>,
+            &event_handler<ExecuteWriteResponseConverter>,
+            &event_handler<HandleValueIndicationConverter>,
+            &event_handler<HandleValueNotificationConverter>
+        };
+
+        // event->hdr.param: connection handle
+        // event->header.event: opcode from the request
+        // event->header.status: success or error code ...
+        // event->pValue: starting after opcode for response; starting after opcode + handle for server initiated responses.
+        // event->handle: handle for server initiated responses
+
+        // traverse all handlers and execute them with the event in input.
+        // exit if an handler has handled the event.
+        for(size_t i = 0; i < (sizeof(handlers)/sizeof(handlers[0])); ++i) {
+            if (handlers[i](event)) {
+                return;
+            }
+        }
+    }
+
+    // pass events not handled to the server side
+    ble::vendor::cordio::GattServer::getInstance().att_cb(event);
+}
+
+} // cordio
+} // vendor
+} // pal
+} // ble
diff --git a/features/FEATURE_BLE/targets/TARGET_CORDIO/CordioPalAttClient.h b/features/FEATURE_BLE/targets/TARGET_CORDIO/CordioPalAttClient.h
index 83d79454d0..dcda0d1be2 100644
--- a/features/FEATURE_BLE/targets/TARGET_CORDIO/CordioPalAttClient.h
+++ b/features/FEATURE_BLE/targets/TARGET_CORDIO/CordioPalAttClient.h
@@ -24,6 +24,8 @@
 #include "att_defs.h"
 #include "ble/pal/PalGap.h"
 #include "CordioPalGap.h"
+#include "PalGattClient.h"
+#include "CordioBLE.h"
 
 namespace ble {
 namespace pal {
@@ -318,53 +320,7 @@ public:
     /**
      * Callback which handle attEvt_t and forward them to on_server_event.
      */
-    static void att_client_handler(const attEvt_t* event)
-    {
-        if (event->hdr.status == ATT_SUCCESS && event->hdr.event == ATT_MTU_UPDATE_IND) {
-            ble::pal::Gap::EventHandler *handler;
-            handler = ble::pal::vendor::cordio::Gap::get_gap().get_event_handler();
-            if (handler) {
-                handler->on_att_mtu_changed(event->hdr.param, event->mtu);
-            }
-            return;
-        }
-
-        // all handlers are stored in a static array
-        static const event_handler_t handlers[] = {
-            &timeout_event_handler,
-            &event_handler<ErrorResponseConverter>,
-            //&event_handler<ExchangeMtuResponseConverter>,
-            &event_handler<FindInformationResponseConverter>,
-            &event_handler<FindByTypeValueResponseConverter>,
-            &event_handler<ReadByTypeResponseConverter>,
-            &event_handler<ReadResponseConverter>,
-            &event_handler<ReadBlobResponseConverter>,
-            &event_handler<ReadMultipleResponseConverter>,
-            &event_handler<ReadBygroupTypeResponseConverter>,
-            &event_handler<WriteResponseConverter>,
-            &event_handler<PrepareWriteResponseConverter>,
-            &event_handler<ExecuteWriteResponseConverter>,
-            &event_handler<HandleValueIndicationConverter>,
-            &event_handler<HandleValueNotificationConverter>
-        };
-
-        // event->hdr.param: connection handle
-        // event->header.event: opcode from the request
-        // event->header.status: success or error code ...
-        // event->pValue: starting after opcode for response; starting after opcode + handle for server initiated responses.
-        // event->handle: handle for server initiated responses
-
-        // traverse all handlers and execute them with the event in input.
-        // exit if an handler has handled the event.
-        for(size_t i = 0; i < (sizeof(handlers)/sizeof(handlers[0])); ++i) {
-            if (handlers[i](event)) {
-                return;
-            }
-        }
-
-        // pass events not handled to the server side
-        ble::vendor::cordio::GattServer::getInstance().att_cb(event);
-    }
+    static void att_client_handler(const attEvt_t* event);
 
 private:
     /**
diff --git a/features/FEATURE_BLE/targets/TARGET_CORDIO/source/CordioGattServer.cpp b/features/FEATURE_BLE/targets/TARGET_CORDIO/source/CordioGattServer.cpp
index 8a096aab26..f3747b0cd6 100644
--- a/features/FEATURE_BLE/targets/TARGET_CORDIO/source/CordioGattServer.cpp
+++ b/features/FEATURE_BLE/targets/TARGET_CORDIO/source/CordioGattServer.cpp
@@ -849,7 +849,12 @@ void GattServer::cccd_cb(attsCccEvt_t *evt)
 
 void GattServer::att_cb(const attEvt_t *evt)
 {
-    if (evt->hdr.status == ATT_SUCCESS && evt->hdr.event == ATTS_HANDLE_VALUE_CNF) {
+    if (evt->hdr.status == ATT_SUCCESS && evt->hdr.event == ATT_MTU_UPDATE_IND) {
+        ::GattServer::EventHandler *handler = getInstance().getEventHandler();
+        if (handler) {
+            handler->onAttMtuChange(evt->hdr.param, evt->mtu);
+        }
+    } else if (evt->hdr.status == ATT_SUCCESS && evt->hdr.event == ATTS_HANDLE_VALUE_CNF) {
         getInstance().handleEvent(GattServerEvents::GATT_EVENT_DATA_SENT, evt->handle);
     }
 }
diff --git a/features/FEATURE_BLE/targets/TARGET_NORDIC/TARGET_NORDIC_SOFTDEVICE/TARGET_MCU_NRF51822/source/nRF5xGattServer.h b/features/FEATURE_BLE/targets/TARGET_NORDIC/TARGET_NORDIC_SOFTDEVICE/TARGET_MCU_NRF51822/source/nRF5xGattServer.h
index b2e5f87dea..a115d24775 100644
--- a/features/FEATURE_BLE/targets/TARGET_NORDIC/TARGET_NORDIC_SOFTDEVICE/TARGET_MCU_NRF51822/source/nRF5xGattServer.h
+++ b/features/FEATURE_BLE/targets/TARGET_NORDIC/TARGET_NORDIC_SOFTDEVICE/TARGET_MCU_NRF51822/source/nRF5xGattServer.h
@@ -41,6 +41,9 @@ public:
     void eventCallback(void);
     void hwCallback(ble_evt_t *p_ble_evt);
 
+    EventHandler* getEventHandler() {
+        return _eventHandler;
+    }
 
 private:
     const static unsigned BLE_TOTAL_CHARACTERISTICS = 20;
diff --git a/features/FEATURE_BLE/targets/TARGET_NORDIC/TARGET_NORDIC_SOFTDEVICE/TARGET_NRF51/source/nRF5xGattServer.h b/features/FEATURE_BLE/targets/TARGET_NORDIC/TARGET_NORDIC_SOFTDEVICE/TARGET_NRF51/source/nRF5xGattServer.h
index 6be90ff733..baedd6473d 100644
--- a/features/FEATURE_BLE/targets/TARGET_NORDIC/TARGET_NORDIC_SOFTDEVICE/TARGET_NRF51/source/nRF5xGattServer.h
+++ b/features/FEATURE_BLE/targets/TARGET_NORDIC/TARGET_NORDIC_SOFTDEVICE/TARGET_NRF51/source/nRF5xGattServer.h
@@ -41,6 +41,9 @@ public:
     void eventCallback(void);
     void hwCallback(const ble_evt_t *p_ble_evt);
 
+    EventHandler* getEventHandler() {
+        return _eventHandler;
+    }
 
 private:
     const static unsigned BLE_TOTAL_CHARACTERISTICS = 20;
diff --git a/features/FEATURE_BLE/targets/TARGET_NORDIC/TARGET_NORDIC_SOFTDEVICE/TARGET_NRF52/source/btle/btle.cpp b/features/FEATURE_BLE/targets/TARGET_NORDIC/TARGET_NORDIC_SOFTDEVICE/TARGET_NRF52/source/btle/btle.cpp
index 57cb8ef3f8..7616973a44 100644
--- a/features/FEATURE_BLE/targets/TARGET_NORDIC/TARGET_NORDIC_SOFTDEVICE/TARGET_NRF52/source/btle/btle.cpp
+++ b/features/FEATURE_BLE/targets/TARGET_NORDIC/TARGET_NORDIC_SOFTDEVICE/TARGET_NRF52/source/btle/btle.cpp
@@ -399,7 +399,8 @@ void btle_handler(const ble_evt_t *p_ble_evt)
                 const ble_gatts_evt_exchange_mtu_request_t &update =
                     p_ble_evt->evt.gatts_evt.params.exchange_mtu_request;
 
-                gap._eventHandler->onAttMtuChange(
+                nRF5xGattServer &gatt_server = (nRF5xGattServer&) ble.getGattServer();
+                gatt_server.getEventHandler()->onAttMtuChange(
                     connection,
                     std::min(NRF_SDH_BLE_GATT_MAX_MTU_SIZE, (int)(update.client_rx_mtu))
                 );
@@ -414,7 +415,8 @@ void btle_handler(const ble_evt_t *p_ble_evt)
                 const ble_gattc_evt_exchange_mtu_rsp_t &update =
                     p_ble_evt->evt.gattc_evt.params.exchange_mtu_rsp;
 
-                gap._eventHandler->onAttMtuChange(
+                nRF5xGattServer &gatt_client = (nRF5xGattClient&) ble.getGattClient();
+                gatt_client.getEventHandler()->onAttMtuChange(
                     connection,
                     std::min(NRF_SDH_BLE_GATT_MAX_MTU_SIZE, (int)(update.server_rx_mtu))
                 );
diff --git a/features/FEATURE_BLE/targets/TARGET_NORDIC/TARGET_NORDIC_SOFTDEVICE/TARGET_NRF52/source/nRF5xGattServer.h b/features/FEATURE_BLE/targets/TARGET_NORDIC/TARGET_NORDIC_SOFTDEVICE/TARGET_NRF52/source/nRF5xGattServer.h
index 253c2d1446..77d6f91fa5 100644
--- a/features/FEATURE_BLE/targets/TARGET_NORDIC/TARGET_NORDIC_SOFTDEVICE/TARGET_NRF52/source/nRF5xGattServer.h
+++ b/features/FEATURE_BLE/targets/TARGET_NORDIC/TARGET_NORDIC_SOFTDEVICE/TARGET_NRF52/source/nRF5xGattServer.h
@@ -41,6 +41,9 @@ public:
     void eventCallback(void);
     void hwCallback(const ble_evt_t *p_ble_evt);
 
+    EventHandler* getEventHandler() {
+        return _eventHandler;
+    }
 
 private:
     const static unsigned BLE_TOTAL_CHARACTERISTICS = NRF_SDH_BLE_TOTAL_CHARACTERISTICS;

From 03b747a6f62963893b3b2d470bcd926f759f4740 Mon Sep 17 00:00:00 2001
From: paul-szczepanek-arm
 <33840200+paul-szczepanek-arm@users.noreply.github.com>
Date: Tue, 5 Feb 2019 12:14:47 +0000
Subject: [PATCH 11/18] Get the pal event handler from pal gattclient

---
 features/FEATURE_BLE/ble/pal/PalGattClient.h  | 23 ++++++++++++++++++-
 .../targets/TARGET_CORDIO/CordioBLE.h         |  7 ++++++
 .../TARGET_CORDIO/CordioPalAttClient.cpp      |  6 +++--
 .../TARGET_CORDIO/source/CordioBLE.cpp        | 10 ++++++--
 4 files changed, 41 insertions(+), 5 deletions(-)

diff --git a/features/FEATURE_BLE/ble/pal/PalGattClient.h b/features/FEATURE_BLE/ble/pal/PalGattClient.h
index d0362240e5..da798e4f5f 100644
--- a/features/FEATURE_BLE/ble/pal/PalGattClient.h
+++ b/features/FEATURE_BLE/ble/pal/PalGattClient.h
@@ -601,8 +601,27 @@ public:
          _transaction_timeout_cb = cb;
      }
 
+     /**
+      * Sets the event handler that us called by the PAL porters to notify the stack of events
+      * which will in turn be passed onto the user application when appropriate.
+      *
+      * @param event_handler The new event handler interface implementation.
+      */
+     void set_event_handler(EventHandler* event_handler) {
+         _event_handler = event_handler;
+     }
+
+     /**
+      * Get the currently registered event handler.
+      *
+      * @return Currently registered event handler. NULL if no event handler is present.
+      */
+     EventHandler* get_event_handler() {
+         return _event_handler;
+     }
+
 protected:
-    GattClient() { }
+    GattClient() : _event_handler(NULL) { }
 
     virtual ~GattClient() { }
 
@@ -640,6 +659,8 @@ protected:
     }
 
 private:
+    EventHandler* _event_handler;
+
     /**
      * Callback called when the client receive a message from the server.
      */
diff --git a/features/FEATURE_BLE/targets/TARGET_CORDIO/CordioBLE.h b/features/FEATURE_BLE/targets/TARGET_CORDIO/CordioBLE.h
index a8083c3bbe..695114911d 100644
--- a/features/FEATURE_BLE/targets/TARGET_CORDIO/CordioBLE.h
+++ b/features/FEATURE_BLE/targets/TARGET_CORDIO/CordioBLE.h
@@ -107,6 +107,13 @@ public:
      */
     virtual generic::GenericGattClient &getGattClient();
 
+    /**
+     * Get the PAL Gatt Client.
+     *
+     * @return PAL Gatt Client.
+     */
+    pal::AttClientToGattClientAdapter &BLE::getPalGattClient();
+
     /**
      * @see BLEInstanceBase::getSecurityManager
      */
diff --git a/features/FEATURE_BLE/targets/TARGET_CORDIO/CordioPalAttClient.cpp b/features/FEATURE_BLE/targets/TARGET_CORDIO/CordioPalAttClient.cpp
index 37b6373d43..35eb9122db 100644
--- a/features/FEATURE_BLE/targets/TARGET_CORDIO/CordioPalAttClient.cpp
+++ b/features/FEATURE_BLE/targets/TARGET_CORDIO/CordioPalAttClient.cpp
@@ -26,8 +26,10 @@ void CordioAttClient::att_client_handler(const attEvt_t* event)
 {
     if (event->hdr.status == ATT_SUCCESS && event->hdr.event == ATT_MTU_UPDATE_IND) {
         ble::vendor::cordio::BLE& ble = ble::vendor::cordio::BLE::deviceInstance();
-        ble::pal::GattClient::EventHandler &handler = ble.getGattClient();
-        handler.on_att_mtu_change(event->hdr.param, event->mtu);
+        ble::pal::GattClient::EventHandler *handler = ble.getPalGattClient().get_event_handler();
+        if (handler) {
+            handler->on_att_mtu_change(event->hdr.param, event->mtu);
+        }
     } else {
         // all handlers are stored in a static array
         static const event_handler_t handlers[] = {
diff --git a/features/FEATURE_BLE/targets/TARGET_CORDIO/source/CordioBLE.cpp b/features/FEATURE_BLE/targets/TARGET_CORDIO/source/CordioBLE.cpp
index 5cffdac74b..de6dd0bd82 100644
--- a/features/FEATURE_BLE/targets/TARGET_CORDIO/source/CordioBLE.cpp
+++ b/features/FEATURE_BLE/targets/TARGET_CORDIO/source/CordioBLE.cpp
@@ -199,13 +199,19 @@ const GattServer& BLE::getGattServer() const
 }
 
 generic::GenericGattClient& BLE::getGattClient()
+{
+    static generic::GenericGattClient gatt_client(&getPalGattClient());
+
+    return gatt_client;
+}
+
+pal::AttClientToGattClientAdapter& BLE::getPalGattClient()
 {
     static pal::AttClientToGattClientAdapter pal_client(
         pal::vendor::cordio::CordioAttClient::get_client()
     );
-    static generic::GenericGattClient client(&pal_client);
 
-    return client;
+    return pal_client;
 }
 
 SecurityManager& BLE::getSecurityManager()

From de60b2a56a3389febaa27dbebe6fdbb7705d4617 Mon Sep 17 00:00:00 2001
From: paul-szczepanek-arm
 <33840200+paul-szczepanek-arm@users.noreply.github.com>
Date: Tue, 5 Feb 2019 12:15:45 +0000
Subject: [PATCH 12/18] remove unused converter

---
 .../TARGET_CORDIO/CordioPalAttClient.cpp      |  1 -
 .../TARGET_CORDIO/CordioPalAttClient.h        | 19 -------------------
 2 files changed, 20 deletions(-)

diff --git a/features/FEATURE_BLE/targets/TARGET_CORDIO/CordioPalAttClient.cpp b/features/FEATURE_BLE/targets/TARGET_CORDIO/CordioPalAttClient.cpp
index 35eb9122db..c642ce9989 100644
--- a/features/FEATURE_BLE/targets/TARGET_CORDIO/CordioPalAttClient.cpp
+++ b/features/FEATURE_BLE/targets/TARGET_CORDIO/CordioPalAttClient.cpp
@@ -35,7 +35,6 @@ void CordioAttClient::att_client_handler(const attEvt_t* event)
         static const event_handler_t handlers[] = {
             &timeout_event_handler,
             &event_handler<ErrorResponseConverter>,
-            //&event_handler<ExchangeMtuResponseConverter>,
             &event_handler<FindInformationResponseConverter>,
             &event_handler<FindByTypeValueResponseConverter>,
             &event_handler<ReadByTypeResponseConverter>,
diff --git a/features/FEATURE_BLE/targets/TARGET_CORDIO/CordioPalAttClient.h b/features/FEATURE_BLE/targets/TARGET_CORDIO/CordioPalAttClient.h
index dcda0d1be2..f646302283 100644
--- a/features/FEATURE_BLE/targets/TARGET_CORDIO/CordioPalAttClient.h
+++ b/features/FEATURE_BLE/targets/TARGET_CORDIO/CordioPalAttClient.h
@@ -400,25 +400,6 @@ private:
         }
     };
 
-    /**
-     * Converter for an AttExchangeMTUResponse.
-     */
-    struct ExchangeMtuResponseConverter  {
-        static bool can_convert(const attEvt_t* event)
-        {
-            if(event->hdr.status == ATT_SUCCESS &&
-                event->hdr.event == ATT_MTU_UPDATE_IND) {
-                return true;
-            }
-            return false;
-        }
-
-        static AttExchangeMTUResponse convert(const attEvt_t* event)
-        {
-            return AttExchangeMTUResponse(event->mtu);
-        }
-    };
-
     /**
      * Converter for a SimpleAttFindInformationResponse.
      */

From 3808db90b25b174eeb4a234da79288e6f10e9443 Mon Sep 17 00:00:00 2001
From: paul-szczepanek-arm
 <33840200+paul-szczepanek-arm@users.noreply.github.com>
Date: Tue, 5 Feb 2019 14:26:16 +0000
Subject: [PATCH 13/18] require pal event handler to be complete

---
 features/FEATURE_BLE/ble/pal/PalGattClient.h | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/features/FEATURE_BLE/ble/pal/PalGattClient.h b/features/FEATURE_BLE/ble/pal/PalGattClient.h
index da798e4f5f..56d72f2b9f 100644
--- a/features/FEATURE_BLE/ble/pal/PalGattClient.h
+++ b/features/FEATURE_BLE/ble/pal/PalGattClient.h
@@ -71,9 +71,7 @@ public:
         virtual void on_att_mtu_change(
             ble::connection_handle_t connection_handle,
             uint16_t att_mtu_size
-        )
-        {
-        }
+        ) = 0;
     };
 
     /**

From 1cea53b6a7c3874cfe070838a63153f1b29c6903 Mon Sep 17 00:00:00 2001
From: paul-szczepanek-arm
 <33840200+paul-szczepanek-arm@users.noreply.github.com>
Date: Tue, 5 Feb 2019 14:35:05 +0000
Subject: [PATCH 14/18] use grandfathered convention for class members names
 and initialise them

---
 features/FEATURE_BLE/ble/GattClient.h               |  6 +++---
 features/FEATURE_BLE/ble/GattServer.h               |  5 +++--
 .../FEATURE_BLE/ble/generic/GenericGattClient.h     | 13 ++++++++++---
 .../targets/TARGET_CORDIO/CordioGattServer.h        |  2 +-
 .../TARGET_MCU_NRF51822/source/nRF5xGattServer.h    |  2 +-
 .../TARGET_NRF51/source/nRF5xGattServer.h           |  2 +-
 .../TARGET_NRF52/source/nRF5xGattServer.h           |  2 +-
 7 files changed, 20 insertions(+), 12 deletions(-)

diff --git a/features/FEATURE_BLE/ble/GattClient.h b/features/FEATURE_BLE/ble/GattClient.h
index 5eff0df04e..828536ffbd 100644
--- a/features/FEATURE_BLE/ble/GattClient.h
+++ b/features/FEATURE_BLE/ble/GattClient.h
@@ -112,7 +112,7 @@ public:
      */
     void setEventHandler(EventHandler *handler)
     {
-        _eventHandler = handler;
+        eventHandler = handler;
     }
 
     /**
@@ -795,7 +795,7 @@ public:
     }
 
 protected:
-    GattClient()
+    GattClient() : eventHandler(NULL)
     {
         /* Empty */
     }
@@ -850,7 +850,7 @@ protected:
     /**
      * Event handler provided by the application.
      */
-    EventHandler *_eventHandler;
+    EventHandler *eventHandler;
 
     /**
      * Callchain containing all registered event handlers for data read
diff --git a/features/FEATURE_BLE/ble/GattServer.h b/features/FEATURE_BLE/ble/GattServer.h
index 8335e7f798..2a1bf417ce 100644
--- a/features/FEATURE_BLE/ble/GattServer.h
+++ b/features/FEATURE_BLE/ble/GattServer.h
@@ -116,7 +116,7 @@ public:
      */
     void setEventHandler(EventHandler *handler)
     {
-        _eventHandler = handler;
+        eventHandler = handler;
     }
 
     /**
@@ -198,6 +198,7 @@ protected:
     GattServer() :
         serviceCount(0),
         characteristicCount(0),
+        eventHandler(NULL),
         dataSentCallChain(),
         dataWrittenCallChain(),
         dataReadCallChain(),
@@ -813,7 +814,7 @@ protected:
     /**
      * Event handler provided by the application.
      */
-    EventHandler *_eventHandler;
+    EventHandler *eventHandler;
 
     /**
      * The total number of services added to the ATT table.
diff --git a/features/FEATURE_BLE/ble/generic/GenericGattClient.h b/features/FEATURE_BLE/ble/generic/GenericGattClient.h
index eece4dfed4..3759e8f1bd 100644
--- a/features/FEATURE_BLE/ble/generic/GenericGattClient.h
+++ b/features/FEATURE_BLE/ble/generic/GenericGattClient.h
@@ -37,13 +37,16 @@ class GenericGattClient : public GattClient,
                           public pal::GattClient::EventHandler {
 public:
 
+    /**
+     * @see pal::GattClient::EventHandler::on_att_mtu_change
+     */
     virtual void on_att_mtu_change(
         ble::connection_handle_t connection_handle,
         uint16_t att_mtu_size
     )
     {
-        if (_eventHandler) {
-            _eventHandler->onAttMtuChange(connection_handle, att_mtu_size);
+        if (eventHandler) {
+            eventHandler->onAttMtuChange(connection_handle, att_mtu_size);
         }
     }
 
@@ -140,8 +143,12 @@ public:
      */
     virtual void set_signing_event_handler(pal::SigningEventMonitor::EventHandler *signing_event_handler);
 
+    /**
+     *  Return the user registered event handler.
+     * @return User registered event handler or NULL if none is present.
+     */
     ::GattClient::EventHandler* getEventHandler() {
-        return _eventHandler;
+        return eventHandler;
     }
 
 private:
diff --git a/features/FEATURE_BLE/targets/TARGET_CORDIO/CordioGattServer.h b/features/FEATURE_BLE/targets/TARGET_CORDIO/CordioGattServer.h
index 84dc2dbdf0..4979ce6249 100644
--- a/features/FEATURE_BLE/targets/TARGET_CORDIO/CordioGattServer.h
+++ b/features/FEATURE_BLE/targets/TARGET_CORDIO/CordioGattServer.h
@@ -63,7 +63,7 @@ public:
     static GattServer &getInstance();
 
     ::GattServer::EventHandler* getEventHandler() {
-        return _eventHandler;
+        return eventHandler;
     }
 
     /**
diff --git a/features/FEATURE_BLE/targets/TARGET_NORDIC/TARGET_NORDIC_SOFTDEVICE/TARGET_MCU_NRF51822/source/nRF5xGattServer.h b/features/FEATURE_BLE/targets/TARGET_NORDIC/TARGET_NORDIC_SOFTDEVICE/TARGET_MCU_NRF51822/source/nRF5xGattServer.h
index a115d24775..7cd58b1cf4 100644
--- a/features/FEATURE_BLE/targets/TARGET_NORDIC/TARGET_NORDIC_SOFTDEVICE/TARGET_MCU_NRF51822/source/nRF5xGattServer.h
+++ b/features/FEATURE_BLE/targets/TARGET_NORDIC/TARGET_NORDIC_SOFTDEVICE/TARGET_MCU_NRF51822/source/nRF5xGattServer.h
@@ -42,7 +42,7 @@ public:
     void hwCallback(ble_evt_t *p_ble_evt);
 
     EventHandler* getEventHandler() {
-        return _eventHandler;
+        return eventHandler;
     }
 
 private:
diff --git a/features/FEATURE_BLE/targets/TARGET_NORDIC/TARGET_NORDIC_SOFTDEVICE/TARGET_NRF51/source/nRF5xGattServer.h b/features/FEATURE_BLE/targets/TARGET_NORDIC/TARGET_NORDIC_SOFTDEVICE/TARGET_NRF51/source/nRF5xGattServer.h
index baedd6473d..8069c8c5e9 100644
--- a/features/FEATURE_BLE/targets/TARGET_NORDIC/TARGET_NORDIC_SOFTDEVICE/TARGET_NRF51/source/nRF5xGattServer.h
+++ b/features/FEATURE_BLE/targets/TARGET_NORDIC/TARGET_NORDIC_SOFTDEVICE/TARGET_NRF51/source/nRF5xGattServer.h
@@ -42,7 +42,7 @@ public:
     void hwCallback(const ble_evt_t *p_ble_evt);
 
     EventHandler* getEventHandler() {
-        return _eventHandler;
+        return eventHandler;
     }
 
 private:
diff --git a/features/FEATURE_BLE/targets/TARGET_NORDIC/TARGET_NORDIC_SOFTDEVICE/TARGET_NRF52/source/nRF5xGattServer.h b/features/FEATURE_BLE/targets/TARGET_NORDIC/TARGET_NORDIC_SOFTDEVICE/TARGET_NRF52/source/nRF5xGattServer.h
index 77d6f91fa5..270a211ac2 100644
--- a/features/FEATURE_BLE/targets/TARGET_NORDIC/TARGET_NORDIC_SOFTDEVICE/TARGET_NRF52/source/nRF5xGattServer.h
+++ b/features/FEATURE_BLE/targets/TARGET_NORDIC/TARGET_NORDIC_SOFTDEVICE/TARGET_NRF52/source/nRF5xGattServer.h
@@ -42,7 +42,7 @@ public:
     void hwCallback(const ble_evt_t *p_ble_evt);
 
     EventHandler* getEventHandler() {
-        return _eventHandler;
+        return eventHandler;
     }
 
 private:

From f52b20c1699b40a98f6acc69ddb775b4140b9a09 Mon Sep 17 00:00:00 2001
From: paul-szczepanek-arm
 <33840200+paul-szczepanek-arm@users.noreply.github.com>
Date: Tue, 5 Feb 2019 17:02:43 +0000
Subject: [PATCH 15/18] move cpp to sources

---
 .../targets/TARGET_CORDIO/{ => source}/CordioPalAttClient.cpp     | 0
 1 file changed, 0 insertions(+), 0 deletions(-)
 rename features/FEATURE_BLE/targets/TARGET_CORDIO/{ => source}/CordioPalAttClient.cpp (100%)

diff --git a/features/FEATURE_BLE/targets/TARGET_CORDIO/CordioPalAttClient.cpp b/features/FEATURE_BLE/targets/TARGET_CORDIO/source/CordioPalAttClient.cpp
similarity index 100%
rename from features/FEATURE_BLE/targets/TARGET_CORDIO/CordioPalAttClient.cpp
rename to features/FEATURE_BLE/targets/TARGET_CORDIO/source/CordioPalAttClient.cpp

From 193092f6d9500b086e9f17eaafdb3e1751fef6e0 Mon Sep 17 00:00:00 2001
From: paul-szczepanek-arm
 <33840200+paul-szczepanek-arm@users.noreply.github.com>
Date: Mon, 11 Feb 2019 09:58:56 +0000
Subject: [PATCH 16/18] added spdx licence ident

---
 .../targets/TARGET_CORDIO/source/CordioPalAttClient.cpp          | 1 +
 1 file changed, 1 insertion(+)

diff --git a/features/FEATURE_BLE/targets/TARGET_CORDIO/source/CordioPalAttClient.cpp b/features/FEATURE_BLE/targets/TARGET_CORDIO/source/CordioPalAttClient.cpp
index c642ce9989..aa0786dec1 100644
--- a/features/FEATURE_BLE/targets/TARGET_CORDIO/source/CordioPalAttClient.cpp
+++ b/features/FEATURE_BLE/targets/TARGET_CORDIO/source/CordioPalAttClient.cpp
@@ -1,5 +1,6 @@
 /* mbed Microcontroller Library
  * Copyright (c) 2019 ARM Limited
+ * SPDX-License-Identifier: Apache-2.0
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.

From cdd5c9f3b09ad9a65804b33bef435fc9ee884d5d Mon Sep 17 00:00:00 2001
From: paul-szczepanek-arm
 <33840200+paul-szczepanek-arm@users.noreply.github.com>
Date: Tue, 12 Feb 2019 10:08:59 +0000
Subject: [PATCH 17/18] fix nrf52 mtu

---
 .../TARGET_NRF52/source/btle/btle.cpp         | 22 +++++++++++--------
 1 file changed, 13 insertions(+), 9 deletions(-)

diff --git a/features/FEATURE_BLE/targets/TARGET_NORDIC/TARGET_NORDIC_SOFTDEVICE/TARGET_NRF52/source/btle/btle.cpp b/features/FEATURE_BLE/targets/TARGET_NORDIC/TARGET_NORDIC_SOFTDEVICE/TARGET_NRF52/source/btle/btle.cpp
index 7616973a44..7fc6bba930 100644
--- a/features/FEATURE_BLE/targets/TARGET_NORDIC/TARGET_NORDIC_SOFTDEVICE/TARGET_NRF52/source/btle/btle.cpp
+++ b/features/FEATURE_BLE/targets/TARGET_NORDIC/TARGET_NORDIC_SOFTDEVICE/TARGET_NRF52/source/btle/btle.cpp
@@ -400,10 +400,12 @@ void btle_handler(const ble_evt_t *p_ble_evt)
                     p_ble_evt->evt.gatts_evt.params.exchange_mtu_request;
 
                 nRF5xGattServer &gatt_server = (nRF5xGattServer&) ble.getGattServer();
-                gatt_server.getEventHandler()->onAttMtuChange(
-                    connection,
-                    std::min(NRF_SDH_BLE_GATT_MAX_MTU_SIZE, (int)(update.client_rx_mtu))
-                );
+                if (gatt_server.getEventHandler()) {
+                    gatt_server.getEventHandler()->onAttMtuChange(
+                        connection,
+                        std::min(NRF_SDH_BLE_GATT_MAX_MTU_SIZE, (int)(update.client_rx_mtu))
+                    );
+                }
             }
             break;
         }
@@ -415,11 +417,13 @@ void btle_handler(const ble_evt_t *p_ble_evt)
                 const ble_gattc_evt_exchange_mtu_rsp_t &update =
                     p_ble_evt->evt.gattc_evt.params.exchange_mtu_rsp;
 
-                nRF5xGattServer &gatt_client = (nRF5xGattClient&) ble.getGattClient();
-                gatt_client.getEventHandler()->onAttMtuChange(
-                    connection,
-                    std::min(NRF_SDH_BLE_GATT_MAX_MTU_SIZE, (int)(update.server_rx_mtu))
-                );
+                nRF5xGattClient &gatt_client = (nRF5xGattClient&) ble.getGattClient();
+                if (gatt_client.get_event_handler()) {
+                    gatt_client.get_event_handler()->on_att_mtu_change(
+                        connection,
+                        std::min(NRF_SDH_BLE_GATT_MAX_MTU_SIZE, (int)(update.server_rx_mtu))
+                    );
+                }
             }
             break;
         }

From d801ed340e5d275ae4fd502c1ed15de229c8bb26 Mon Sep 17 00:00:00 2001
From: paul-szczepanek-arm
 <33840200+paul-szczepanek-arm@users.noreply.github.com>
Date: Thu, 14 Feb 2019 10:00:42 +0000
Subject: [PATCH 18/18] removed redundant qualifier tripping up GCC

---
 features/FEATURE_BLE/targets/TARGET_CORDIO/CordioBLE.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/features/FEATURE_BLE/targets/TARGET_CORDIO/CordioBLE.h b/features/FEATURE_BLE/targets/TARGET_CORDIO/CordioBLE.h
index 695114911d..57596f121a 100644
--- a/features/FEATURE_BLE/targets/TARGET_CORDIO/CordioBLE.h
+++ b/features/FEATURE_BLE/targets/TARGET_CORDIO/CordioBLE.h
@@ -112,7 +112,7 @@ public:
      *
      * @return PAL Gatt Client.
      */
-    pal::AttClientToGattClientAdapter &BLE::getPalGattClient();
+    pal::AttClientToGattClientAdapter &getPalGattClient();
 
     /**
      * @see BLEInstanceBase::getSecurityManager