Linux HAL updates

1. The type correction was merged as part of
   eive/fsfw#7 in the
   EIVE project. Quotation of PR

definition of getSpiParameters is `void getSpiParameters(spi::SpiModes& spiMode, uint32_t& spiSpeed, UncommonParameters* parameters = nullptr) const;`.

Here, size_t spiSpeed is passed, which implicitely gets converted to a temporary, which can not be bound to uint32_t& and, at least in gcc 9.3.0, leads to a compiler error.

2. Allow flushing the UART buffers

hal/src/fsfw_hal/linux/spi/SpiComIF.cpp

@@ -82,7 +82,7 @@ ReturnValue_t SpiComIF::initializeInterface(CookieIF *cookie) {
         gpioComIF->pullHigh(gpioId);
     }
 
-    size_t spiSpeed = 0;
+    uint32_t spiSpeed = 0;
     spi::SpiModes spiMode = spi::SpiModes::MODE_0;
 
     SpiCookie::UncommonParameters params;

hal/src/fsfw_hal/linux/uart/UartComIF.cpp

@@ -443,6 +443,51 @@ ReturnValue_t UartComIF::readReceivedMessage(CookieIF *cookie,
     return RETURN_OK;
 }
 
+ReturnValue_t UartComIF::flushUartRxBuffer(CookieIF *cookie) {
+    std::string deviceFile;
+    UartDeviceMapIter uartDeviceMapIter;
+    UartCookie* uartCookie = dynamic_cast<UartCookie*>(cookie);
+    if(uartCookie == nullptr) {
+        sif::warning << "UartComIF::flushUartRxBuffer: Invalid uart cookie!" << std::endl;
+        return NULLPOINTER;
+    }
+    deviceFile = uartCookie->getDeviceFile();
+    uartDeviceMapIter = uartDeviceMap.find(deviceFile);
+    int fd = uartDeviceMapIter->second.fileDescriptor;
+    tcflush(fd, TCIFLUSH);
+    return RETURN_OK;
+}
+
+ReturnValue_t UartComIF::flushUartTxBuffer(CookieIF *cookie) {
+    std::string deviceFile;
+    UartDeviceMapIter uartDeviceMapIter;
+    UartCookie* uartCookie = dynamic_cast<UartCookie*>(cookie);
+    if(uartCookie == nullptr) {
+        sif::warning << "UartComIF::flushUartTxBuffer: Invalid uart cookie!" << std::endl;
+        return NULLPOINTER;
+    }
+    deviceFile = uartCookie->getDeviceFile();
+    uartDeviceMapIter = uartDeviceMap.find(deviceFile);
+    int fd = uartDeviceMapIter->second.fileDescriptor;
+    tcflush(fd, TCOFLUSH);
+    return RETURN_OK;
+}
+
+ReturnValue_t UartComIF::flushUartTxAndRxBuf(CookieIF *cookie) {
+    std::string deviceFile;
+    UartDeviceMapIter uartDeviceMapIter;
+    UartCookie* uartCookie = dynamic_cast<UartCookie*>(cookie);
+    if(uartCookie == nullptr) {
+        sif::warning << "UartComIF::flushUartTxAndRxBuf: Invalid uart cookie!" << std::endl;
+        return NULLPOINTER;
+    }
+    deviceFile = uartCookie->getDeviceFile();
+    uartDeviceMapIter = uartDeviceMap.find(deviceFile);
+    int fd = uartDeviceMapIter->second.fileDescriptor;
+    tcflush(fd, TCIOFLUSH);
+    return RETURN_OK;
+}
+
 void UartComIF::setUartMode(struct termios *options, UartCookie &uartCookie) {
     UartModes uartMode = uartCookie.getUartMode();
     if(uartMode == UartModes::NON_CANONICAL) {

hal/src/fsfw_hal/linux/uart/UartComIF.h

@@ -41,6 +41,21 @@ public:
     ReturnValue_t readReceivedMessage(CookieIF *cookie, uint8_t **buffer,
             size_t *size) override;
 
+    /**
+     * @brief   This function discards all data received but not read in the UART buffer.
+     */
+    ReturnValue_t flushUartRxBuffer(CookieIF *cookie);
+
+    /**
+     * @brief   This function discards all data in the transmit buffer of the UART driver.
+     */
+    ReturnValue_t flushUartTxBuffer(CookieIF *cookie);
+
+    /**
+     * @brief   This function discards both data in the transmit and receive buffer of the UART.
+     */
+    ReturnValue_t flushUartTxAndRxBuf(CookieIF *cookie);
+
 private:
 
     using UartDeviceFile_t = std::string;