Merge pull request #5088 from kjbracey-arm/uartserial_flow

UARTSerial: add flow control and format APIs

Author: theotherjimmy

drivers/UARTSerial.cpp

@@ -32,6 +32,7 @@ UARTSerial::UARTSerial(PinName tx, PinName rx, int baud) :
         SerialBase(tx, rx, baud),
         _blocking(true),
         _tx_irq_enabled(false),
+        _rx_irq_enabled(true),
         _dcd_irq(NULL)
 {
     /* Attatch IRQ routines to the serial device. */
@@ -68,6 +69,22 @@ void UARTSerial::set_data_carrier_detect(PinName dcd_pin, bool active_high)
     }
 }
 
+void UARTSerial::set_format(int bits, Parity parity, int stop_bits)
+{
+    api_lock();
+    SerialBase::format(bits, parity, stop_bits);
+    api_unlock();
+}
+
+#if DEVICE_SERIAL_FC
+void UARTSerial::set_flow_control(Flow type, PinName flow1, PinName flow2)
+{
+    api_lock();
+    SerialBase::set_flow_control(type, flow1, flow2);
+    api_unlock();
+}
+#endif
+
 int UARTSerial::close()
 {
     /* Does not let us pass a file descriptor. So how to close ?
@@ -176,6 +193,16 @@ ssize_t UARTSerial::read(void* buffer, size_t length)
         data_read++;
     }
 
+    core_util_critical_section_enter();
+    if (!_rx_irq_enabled) {
+        UARTSerial::rx_irq();               // only read from hardware in one place
+        if (!_rxbuf.full()) {
+            SerialBase::attach(callback(this, &UARTSerial::rx_irq), RxIrq);
+            _rx_irq_enabled = true;
+        }
+    }
+    core_util_critical_section_exit();
+
     api_unlock();
 
     return data_read;
@@ -243,13 +270,14 @@ void UARTSerial::rx_irq(void)
 
     /* Fill in the receive buffer if the peripheral is readable
      * and receive buffer is not full. */
-    while (SerialBase::readable()) {
+    while (!_rxbuf.full() && SerialBase::readable()) {
         char data = SerialBase::_base_getc();
-        if (!_rxbuf.full()) {
-            _rxbuf.push(data);
-        } else {
-            /* Drop - can we report in some way? */
-        }
+        _rxbuf.push(data);
+    }
+
+    if (_rx_irq_enabled && _rxbuf.full()) {
+        SerialBase::attach(NULL, RxIrq);
+        _rx_irq_enabled = false;
     }
 
     /* Report the File handler that data is ready to be read from the buffer. */

drivers/UARTSerial.h

@@ -164,6 +164,42 @@ class UARTSerial : private SerialBase, public FileHandle, private NonCopyable<UA
      */
     void set_baud(int baud);
 
+    // Expose private SerialBase::Parity as UARTSerial::Parity
+    using SerialBase::Parity;
+    // In C++11, we wouldn't need to also have using directives for each value
+    using SerialBase::None;
+    using SerialBase::Odd;
+    using SerialBase::Even;
+    using SerialBase::Forced1;
+    using SerialBase::Forced0;
+
+    /** Set the transmission format used by the serial port
+     *
+     *  @param bits The number of bits in a word (5-8; default = 8)
+     *  @param parity The parity used (None, Odd, Even, Forced1, Forced0; default = None)
+     *  @param stop_bits The number of stop bits (1 or 2; default = 1)
+     */
+    void set_format(int bits=8, Parity parity=UARTSerial::None, int stop_bits=1);
+
+#if DEVICE_SERIAL_FC
+    // For now use the base enum - but in future we may have extra options
+    // such as XON/XOFF or manual GPIO RTSCTS.
+    using SerialBase::Flow;
+    // In C++11, we wouldn't need to also have using directives for each value
+    using SerialBase::Disabled;
+    using SerialBase::RTS;
+    using SerialBase::CTS;
+    using SerialBase::RTSCTS;
+
+    /** Set the flow control type on the serial port
+     *
+     *  @param type the flow control type (Disabled, RTS, CTS, RTSCTS)
+     *  @param flow1 the first flow control pin (RTS for RTS or RTSCTS, CTS for CTS)
+     *  @param flow2 the second flow control pin (CTS for RTSCTS)
+     */
+    void set_flow_control(Flow type, PinName flow1=NC, PinName flow2=NC);
+#endif
+
 private:
 
     void wait_ms(uint32_t millisec);
@@ -192,6 +228,7 @@ class UARTSerial : private SerialBase, public FileHandle, private NonCopyable<UA
 
     bool _blocking;
     bool _tx_irq_enabled;
+    bool _rx_irq_enabled;
     InterruptIn *_dcd_irq;
 
     /** Device Hanged up