Merge pull request #10924 from ghseb/free-serial-resources-2

Free serial resources if not needed anymore

UNITTESTS/stubs/SerialBase_stub.cpp

@@ -19,7 +19,8 @@
 
 namespace mbed {
 
-SerialBase::SerialBase(PinName tx, PinName rx, int baud)
+SerialBase::SerialBase(PinName tx, PinName rx, int baud) :
+    _tx_pin(tx), _rx_pin(rx)
 {
 }
 

drivers/SerialBase.h

@@ -155,6 +155,30 @@ public:
      */
     void send_break();
 
+    /** Enable serial input
+     *
+     * If both serial input and serial output are disabled, the
+     * peripheral is freed. If either serial input or serial
+     * output is re-enabled, the peripheral is reinitialized.
+     *
+     * On re-initialization rx interrupts will be enabled if a
+     * rx handler is attached. The rx handler is called once
+     * during re-initialization.
+     */
+    void enable_input(bool enable = true);
+
+    /** Enable serial output
+     *
+     * If both serial input and serial output are disabled, the
+     * peripheral is freed. If either serial input or serial
+     * output is re-enabled, the peripheral is reinitialized.
+     *
+     * On re-initialization tx interrupts will be enabled if a
+     * tx handler is attached. The tx handler is called once
+     * during re-initialization.
+     */
+    void enable_output(bool enable = true);
+
 #if !defined(DOXYGEN_ONLY)
 protected:
 
@@ -295,6 +319,14 @@ protected:
 
     int _base_putc(int c);
 
+    /** Initialize serial port
+     */
+    void _init();
+
+    /** Deinitialize serial port
+     */
+    void _deinit();
+
 #if DEVICE_SERIAL_ASYNCH
     CThunk<SerialBase> _thunk_irq;
     DMAUsage _tx_usage;
@@ -308,6 +340,17 @@ protected:
     serial_t         _serial;
     Callback<void()> _irq[IrqCnt];
     int              _baud;
+    bool             _rx_enabled;
+    bool             _tx_enabled;
+    const PinName    _tx_pin;
+    const PinName    _rx_pin;
+
+#if DEVICE_SERIAL_FC
+    Flow             _flow_type;
+    PinName          _flow1;
+    PinName          _flow2;
+#endif
+
 #endif
 };
 

drivers/source/SerialBase.cpp

@@ -30,7 +30,17 @@ SerialBase::SerialBase(PinName tx, PinName rx, int baud) :
     _rx_callback(NULL), _tx_asynch_set(false),
     _rx_asynch_set(false),
 #endif
-    _serial(), _baud(baud)
+    _serial(),
+    _baud(baud),
+#if DEVICE_SERIAL_FC
+    _flow_type(Disabled),
+    _flow1(NC),
+    _flow2(NC),
+#endif
+    _rx_enabled(true),
+    _tx_enabled(true),
+    _tx_pin(tx),
+    _rx_pin(rx)
 {
     // No lock needed in the constructor
 
@@ -38,9 +48,7 @@ SerialBase::SerialBase(PinName tx, PinName rx, int baud) :
         _irq[i] = NULL;
     }
 
-    serial_init(&_serial, tx, rx);
+    _init();
-    serial_baud(&_serial, _baud);
-    serial_irq_handler(&_serial, SerialBase::_irq_handler, (uint32_t)this);
 }
 
 void SerialBase::baud(int baudrate)
@@ -78,6 +86,11 @@ int SerialBase::writeable()
 void SerialBase::attach(Callback<void()> func, IrqType type)
 {
     lock();
+    const bool enabled { (_rx_enabled &&(type == RxIrq)) || (_tx_enabled &&(type == TxIrq)) };
+    // If corresponding direction is not enabled only update the handler
+    if (!enabled) {
+        _irq[type] = func;
+    } else {
         // Disable interrupts when attaching interrupt handler
         core_util_critical_section_enter();
         if (func) {
@@ -96,6 +109,7 @@ void SerialBase::attach(Callback<void()> func, IrqType type)
             serial_irq_set(&_serial, (SerialIrq)type, 0);
         }
         core_util_critical_section_exit();
+    }
     unlock();
 }
 
@@ -120,6 +134,95 @@ int SerialBase::_base_putc(int c)
     return c;
 }
 
+void SerialBase::_init()
+{
+    serial_init(&_serial, _tx_pin, _rx_pin);
+#if DEVICE_SERIAL_FC
+    set_flow_control(_flow_type, _flow1, _flow2);
+#endif
+    serial_baud(&_serial, _baud);
+    serial_irq_handler(&_serial, SerialBase::_irq_handler, (uint32_t)this);
+}
+
+void SerialBase::_deinit()
+{
+    serial_free(&_serial);
+}
+
+void SerialBase::enable_input(bool enable)
+{
+    lock();
+    if (_rx_enabled != enable) {
+        if (enable && !_tx_enabled) {
+            _init();
+        }
+
+        core_util_critical_section_enter();
+        if (enable) {
+            // Enable rx IRQ and lock deep sleep if a rx handler is attached
+            // (indicated by rx IRQ callback not NULL)
+            if (_irq[RxIrq]) {
+                _irq[RxIrq].call();
+                sleep_manager_lock_deep_sleep();
+                serial_irq_set(&_serial, (SerialIrq)RxIrq, 1);
+            }
+        } else {
+            // Disable rx IRQ
+            serial_irq_set(&_serial, (SerialIrq)RxIrq, 0);
+            // Unlock deep sleep if a rx handler is attached
+            // (indicated by rx IRQ callback not NULL)
+            if (_irq[RxIrq]) {
+                sleep_manager_unlock_deep_sleep();
+            }
+        }
+        core_util_critical_section_exit();
+
+        _rx_enabled = enable;
+
+        if (!enable && !_tx_enabled) {
+            _deinit();
+        }
+    }
+    unlock();
+}
+
+void SerialBase::enable_output(bool enable)
+{
+    lock();
+    if (_tx_enabled != enable) {
+        if (enable && !_rx_enabled) {
+            _init();
+        }
+
+        core_util_critical_section_enter();
+        if (enable) {
+            // Enable tx IRQ and lock deep sleep if a tx handler is attached
+            // (indicated by tx IRQ callback not NULL)
+            if (_irq[TxIrq]) {
+                _irq[TxIrq].call();
+                sleep_manager_lock_deep_sleep();
+                serial_irq_set(&_serial, (SerialIrq)TxIrq, 1);
+            }
+        } else {
+            // Disable tx IRQ
+            serial_irq_set(&_serial, (SerialIrq)TxIrq, 0);
+            // Unlock deep sleep if a tx handler is attached
+            // (indicated by tx IRQ callback not NULL)
+            if (_irq[TxIrq]) {
+                sleep_manager_unlock_deep_sleep();
+            }
+        }
+        core_util_critical_section_exit();
+
+        _tx_enabled = enable;
+
+        if (!enable && !_rx_enabled) {
+            _deinit();
+        }
+    }
+    unlock();
+}
+
 void SerialBase::set_break()
 {
     lock();
@@ -175,6 +278,11 @@ SerialBase::~SerialBase()
 void SerialBase::set_flow_control(Flow type, PinName flow1, PinName flow2)
 {
     lock();
+
+    _flow_type = type;
+    _flow1 = flow1;
+    _flow2 = flow2;
+
     FlowControl flow_type = (FlowControl)type;
     switch (type) {
         case RTS:

drivers/source/UARTSerial.cpp

@@ -366,38 +366,18 @@ void UARTSerial::disable_tx_irq()
 
 int UARTSerial::enable_input(bool enabled)
 {
-    core_util_critical_section_enter();
+    api_lock();
-    if (_rx_enabled != enabled) {
+    SerialBase::enable_input(enabled);
-        if (enabled) {
+    api_unlock();
-            UARTSerial::rx_irq();
-            if (!_rxbuf.full()) {
-                enable_rx_irq();
-            }
-        } else {
-            disable_rx_irq();
-        }
-        _rx_enabled = enabled;
-    }
-    core_util_critical_section_exit();
 
     return 0;
 }
 
 int UARTSerial::enable_output(bool enabled)
 {
-    core_util_critical_section_enter();
+    api_lock();
-    if (_tx_enabled != enabled) {
+    SerialBase::enable_output(enabled);
-        if (enabled) {
+    api_unlock();
-            UARTSerial::tx_irq();
-            if (!_txbuf.empty()) {
-                enable_tx_irq();
-            }
-        } else {
-            disable_tx_irq();
-        }
-        _tx_enabled = enabled;
-    }
-    core_util_critical_section_exit();
 
     return 0;
 }

targets/TARGET_Maxim/TARGET_MAX32600/serial_api.c

@@ -96,6 +96,12 @@ void serial_init(serial_t *obj, PinName tx, PinName rx)
     }
 }
 
+//******************************************************************************
+void serial_free(serial_t *obj)
+{
+    serial_irq_ids[obj->index];
+}
+
 //******************************************************************************
 void serial_baud(serial_t *obj, int baudrate)
 {

targets/TARGET_Maxim/TARGET_MAX32620C/serial_api.c

@@ -418,3 +418,8 @@ const PinMap *serial_rts_pinmap()
 {
     return PinMap_UART_RTS;
 }
+
+void serial_free(serial_t *obj)
+{
+    // Not implemented
+}

targets/TARGET_Maxim/TARGET_MAX32625/serial_api.c

@@ -115,6 +115,13 @@ void serial_init(serial_t *obj, PinName tx, PinName rx)
     MBED_ASSERT(retval == E_NO_ERROR);
 }
 
+//******************************************************************************
+void serial_free(serial_t *obj)
+{
+    UART_Shutdown(obj->uart);
+    objs[obj->index] = 0;
+}
+
 //******************************************************************************
 void serial_baud(serial_t *obj, int baudrate)
 {

targets/TARGET_Maxim/TARGET_MAX32630/serial_api.c

@@ -115,6 +115,13 @@ void serial_init(serial_t *obj, PinName tx, PinName rx)
     MBED_ASSERT(retval == E_NO_ERROR);
 }
 
+//******************************************************************************
+void serial_free(serial_t *obj)
+{
+    UART_Shutdown(obj->uart);
+    objs[obj->index] = 0;
+}
+
 //******************************************************************************
 void serial_baud(serial_t *obj, int baudrate)
 {