Adding thread safety

Making our LoRaWAN stack thread safe. If RTOS is not present, locks
don't do anything. ScopedLock is used to automate the lock release on
context expiry.

Author: Hasnain Virk

features/lorawan/LoRaWANInterface.cpp

@@ -34,95 +34,114 @@ LoRaWANInterface::~LoRaWANInterface()
 
 lorawan_status_t LoRaWANInterface::initialize(EventQueue *queue)
 {
+    Lock lock(*this);
     return _lw_stack.initialize_mac_layer(queue);
 }
 
 lorawan_status_t LoRaWANInterface::connect()
 {
+    Lock lock(*this);
     return _lw_stack.connect();
 }
 
 lorawan_status_t LoRaWANInterface::connect(const lorawan_connect_t &connect)
 {
+    Lock lock(*this);
     return _lw_stack.connect(connect);
 }
 
 lorawan_status_t LoRaWANInterface::disconnect()
 {
+    Lock lock(*this);
     return _lw_stack.shutdown();
 }
 
 lorawan_status_t LoRaWANInterface::add_link_check_request()
 {
+    Lock lock(*this);
     return _lw_stack.set_link_check_request();
 }
 
 void LoRaWANInterface::remove_link_check_request()
 {
+    Lock lock(*this);
     _lw_stack.remove_link_check_request();
 }
 
 lorawan_status_t LoRaWANInterface::set_datarate(uint8_t data_rate)
 {
+    Lock lock(*this);
     return _lw_stack.set_channel_data_rate(data_rate);
 }
 
 lorawan_status_t LoRaWANInterface::set_confirmed_msg_retries(uint8_t count)
 {
+    Lock lock(*this);
     return _lw_stack.set_confirmed_msg_retry(count);
 }
 
 lorawan_status_t LoRaWANInterface::enable_adaptive_datarate()
 {
+    Lock lock(*this);
     return _lw_stack.enable_adaptive_datarate(true);
 }
 
 lorawan_status_t LoRaWANInterface::disable_adaptive_datarate()
 {
+    Lock lock(*this);
     return _lw_stack.enable_adaptive_datarate(false);
 }
 
 lorawan_status_t LoRaWANInterface::set_channel_plan(const lorawan_channelplan_t &channel_plan)
 {
+    Lock lock(*this);
     return _lw_stack.add_channels(channel_plan);
 }
 
 lorawan_status_t LoRaWANInterface::get_channel_plan(lorawan_channelplan_t &channel_plan)
 {
+    Lock lock(*this);
     return _lw_stack.get_enabled_channels(channel_plan);
 }
 
 lorawan_status_t LoRaWANInterface::remove_channel(uint8_t id)
 {
+    Lock lock(*this);
     return _lw_stack.remove_a_channel(id);
 }
 
 lorawan_status_t LoRaWANInterface::remove_channel_plan()
 {
+    Lock lock(*this);
     return _lw_stack.drop_channel_list();
 }
 
 int16_t LoRaWANInterface::send(uint8_t port, const uint8_t* data, uint16_t length, int flags)
 {
+    Lock lock(*this);
     return _lw_stack.handle_tx(port, data, length, flags);
 }
 
 int16_t LoRaWANInterface::receive(uint8_t port, uint8_t* data, uint16_t length, int flags)
 {
+    Lock lock(*this);
     return _lw_stack.handle_rx(data, length, port, flags, true);
 }
 
 int16_t LoRaWANInterface::receive(uint8_t* data, uint16_t length, uint8_t& port, int& flags)
 {
+    Lock lock(*this);
     return _lw_stack.handle_rx(data, length, port, flags, false);
 }
 
 lorawan_status_t LoRaWANInterface::add_app_callbacks(lorawan_app_callbacks_t *callbacks)
 {
+    Lock lock(*this);
     return _lw_stack.set_lora_callbacks(callbacks);
 }
 
 lorawan_status_t LoRaWANInterface::set_device_class(const device_class_t device_class)
 {
+    Lock lock(*this);
     return _lw_stack.set_device_class(device_class);
 }

features/lorawan/LoRaWANInterface.h

@@ -19,6 +19,7 @@
 #define LORAWANINTERFACE_H_
 
 #include "platform/Callback.h"
+#include "platform/ScopedLock.h"
 #include "LoRaWANStack.h"
 #include "LoRaRadio.h"
 #include "LoRaWANBase.h"
@@ -435,7 +436,13 @@ class LoRaWANInterface: public LoRaWANBase {
      */
     virtual lorawan_status_t set_device_class(const device_class_t device_class);
 
+    void lock(void) { _lw_stack.lock(); }
+    void unlock(void) { _lw_stack.unlock(); }
+
+
 private:
+    typedef mbed::ScopedLock<LoRaWANInterface> Lock;
+
     LoRaWANStack _lw_stack;
 };
 

features/lorawan/LoRaWANStack.h

@@ -44,6 +44,7 @@
 #include "events/EventQueue.h"
 #include "platform/Callback.h"
 #include "platform/NonCopyable.h"
+#include "platform/ScopedLock.h"
 
 #include "lorastack/mac/LoRaMac.h"
 #include "system/LoRaWANTimer.h"
@@ -395,7 +396,11 @@ class LoRaWANStack: private mbed::NonCopyable<LoRaWANStack> {
      */
     lorawan_status_t set_device_class(const device_class_t& device_class);
 
+    void lock(void) { _loramac.lock(); }
+    void unlock(void) { _loramac.unlock(); }
+
 private:
+    typedef mbed::ScopedLock<LoRaWANStack> Lock;
     /**
      * Checks if the user provided port is valid or not
      */

features/lorawan/lorastack/mac/LoRaMac.h

@@ -51,7 +51,11 @@
 #include "LoRaMacChannelPlan.h"
 #include "LoRaMacCommand.h"
 #include "LoRaMacCrypto.h"
+#if MBED_CONF_RTOS_PRESENT
+#include "rtos/Mutex.h"
+#endif
 
+#include "platform/ScopedLock.h"
 
 class LoRaMac {
 
@@ -422,6 +426,24 @@ class LoRaMac {
      */
     void on_mac_state_check_timer_event(void);
 
+    /**
+     * These locks trample through to the upper layers and make
+     * the stack thread safe.
+     */
+#if MBED_CONF_RTOS_PRESENT
+    void lock(void) { osStatus status = _mutex.lock(); MBED_ASSERT(status == osOK); }
+    void unlock(void) { osStatus status = _mutex.unlock(); MBED_ASSERT(status == osOK); }
+#else
+    void lock(void) { }
+    void unlock(void) { }
+#endif
+
+private:
+    typedef mbed::ScopedLock<LoRaMac> Lock;
+#if MBED_CONF_RTOS_PRESENT
+    rtos::Mutex _mutex;
+#endif
+
     /**
      * Function executed on duty cycle delayed Tx  timer event
      */