Fix the UART change makes BLE library failed

1. The uart_fifo_fill doesn't check the FIFO's length and failed to send out all data
2. Check the FIFO status register before write data in FIFO

Author: sgbihu

cores/arduino/UARTClass.cpp

@@ -168,7 +168,7 @@ int UARTClass::read( void )
 
 void UARTClass::flush( void )
 {
-  while (_tx_buffer->_iHead != _tx_buffer->_iTail); //wait for transmit data to be sent
+  while (_tx_buffer->_iHead != *(volatile int*)&(_tx_buffer->_iTail)); //wait for transmit data to be sent
   // Wait for transmission to complete
   while(!uart_tx_complete(CONFIG_UART_CONSOLE_INDEX));
 }
@@ -179,12 +179,11 @@ size_t UARTClass::write( const uint8_t uc_data )
     return(0);
 
   // Is the hardware currently busy?
-  if (_tx_buffer->_iTail != _tx_buffer->_iHead)
+  if (_tx_buffer->_iTail != _tx_buffer->_iHead || !uart_tx_ready(CONFIG_UART_CONSOLE_INDEX))
   {
     // If busy we buffer
     int l = (_tx_buffer->_iHead + 1) % UART_BUFFER_SIZE;
-    while (_tx_buffer->_iTail == l)
-      ; // Spin locks if we're about to overwrite the buffer. This continues once the data is sent
+    while (*(volatile int*)&(_tx_buffer->_iTail) == l); // Spin locks if we're about to overwrite the buffer. This continues once the data is sent
 
     _tx_buffer->_aucBuffer[_tx_buffer->_iHead] = uc_data;
     _tx_buffer->_iHead = l;
@@ -201,21 +200,29 @@ size_t UARTClass::write( const uint8_t uc_data )
 
 void UARTClass::IrqHandler( void )
 {
-  uint8_t uc_data;
-  int ret;
-  ret = uart_poll_in(CONFIG_UART_CONSOLE_INDEX, &uc_data);
-  
-  while ( ret != -1 ) {
-    _rx_buffer->store_char(uc_data);
+  uart_irq_update(CONFIG_UART_CONSOLE_INDEX);
+  // if irq is Receiver Data Available
+  if(uart_irq_rx_ready(CONFIG_UART_CONSOLE_INDEX))
+  {
+    uint8_t uc_data;
+    int ret;
     ret = uart_poll_in(CONFIG_UART_CONSOLE_INDEX, &uc_data);
+    
+    while ( ret != -1 ) {
+      _rx_buffer->store_char(uc_data);
+      ret = uart_poll_in(CONFIG_UART_CONSOLE_INDEX, &uc_data);
+    }
   }
 
-  // Do we need to keep sending data?
-  if (!uart_irq_tx_ready(CONFIG_UART_CONSOLE_INDEX))
+  // if irq is Transmitter Holding Register
+  else if(uart_irq_tx_ready(CONFIG_UART_CONSOLE_INDEX))
   {
-    if (_tx_buffer->_iTail != _tx_buffer->_iHead) {
-      uart_poll_out(CONFIG_UART_CONSOLE_INDEX, _tx_buffer->_aucBuffer[_tx_buffer->_iTail]);
-      _tx_buffer->_iTail = (unsigned int)(_tx_buffer->_iTail + 1) % UART_BUFFER_SIZE;
+    if(_tx_buffer->_iTail != _tx_buffer->_iHead)
+    {
+      int end = (_tx_buffer->_iTail < _tx_buffer->_iHead) ? _tx_buffer->_iHead:UART_BUFFER_SIZE;
+      int l = min(end - _tx_buffer->_iTail, UART_FIFO_SIZE);
+      uart_fifo_fill(CONFIG_UART_CONSOLE_INDEX, _tx_buffer->_aucBuffer+_tx_buffer->_iTail, l);
+      _tx_buffer->_iTail = (_tx_buffer->_iTail+l)%UART_BUFFER_SIZE;
     }
     else
     {

system/libarc32_arduino101/drivers/ns16550.c

@@ -340,7 +340,7 @@ unsigned char uart_poll_out(
 	)
 {
 	/* wait for transmitter to ready to accept a character */
-	while ((INBYTE(LSR(which)) & LSR_TEMT) == 0)
+	while ((INBYTE(LSR(which)) & LSR_THRE) == 0)
 		;
 
 	OUTBYTE(THR(which), outChar);
@@ -352,6 +352,8 @@ unsigned char uart_poll_out(
 *
 * uart_fifo_fill - fill FIFO with data
 *
+* It is up to the caller to make sure that FIFO capcity is not exceeded
+*
 * RETURNS: number of bytes sent
 */
 
@@ -362,8 +364,9 @@ int uart_fifo_fill(int which, /* UART on which to send */
 {
 	int i;
 
-	for (i = 0; i < size && (INBYTE(LSR(which)) &
-			LSR_BOTH_EMPTY) != 0; i++) {
+	for (i = 0; i < size  && (INBYTE(LSR(which)) &
+			LSR_BOTH_EMPTY) != 0; i++) 
+	{
 		OUTBYTE(THR(which), txData[i]);
 	}
 	return i;
@@ -622,7 +625,6 @@ void uart_int_connect(int which,	   /* UART to which to connect */
 		      )
 {
 	interrupt_connect((unsigned int)uart[which].irq, isr);
-    interrupt_priority_set ((int)uart[which].irq, uart[which].intPri);
 	interrupt_enable((unsigned int)uart[which].irq);
 	/* set the Host Processor Interrupt Routing Mask */
 	SOC_UNMASK_INTERRUPTS(INT_UART_0_MASK + (which * UART_REG_ADDR_INTERVAL));
@@ -641,6 +643,19 @@ uint8_t uart_tx_complete(int which)
 	return INBYTE(LSR(which)) & LSR_TEMT;
 }
 
+/*******************************************************************************
+*
+* uart_tx_complete - check if tx holding register is empty
+*
+* RETURNS: zero if register is non-empty, 
+*          non-zero if register is empty (ready to receive new data)
+*/
+
+uint8_t uart_tx_ready(int which)
+{
+	return INBYTE(LSR(which)) & LSR_THRE;
+}
+
 /*******************************************************************************
 *
 * uart_loop_enable - enable loopback