/*********************************************************************************
*  Embedded Studio 2007                                   
*                                                                                
*  File: ES_UART.c
*  Desc: PC16550 UART Driver Functions
*
**********************************************************************************/

//Includes
#include "ES_UART.h"

/*********************************************************************************************
* Function: UART_Open
*
* Desc: This function opens the UART port to use in FIFO Polling mode
*
* Params: int ch - channel number (1 or 2)
*		ConfigStruct *pConfig - pointer to the port Configuration
*		FpgaUartCtrlStruct *pUart - pointer to the UART control block
*
* Returns: bool - true if the port opens successfully, false otherwise
*
* Notes: 
*
*********************************************************************************************/
bool UART_Open(int ch, FpgaUartCtrlStruct *pUart, UartConfigStruct *pConfig)
{
    if(ch == 0)    //FPGA UART 1
    {
        pUart->RBR = pFPGA1_UART_RBR;
        pUart->THR = pFPGA1_UART_THR;
        pUart->DLL = pFPGA1_UART_DLL;
        pUart->DLM = pFPGA1_UART_DLM;
        pUart->IER = pFPGA1_UART_IER;
        pUart->IIR = pFPGA1_UART_IIR;
        pUart->FCR = pFPGA1_UART_FCR;
        pUart->LCR = pFPGA1_UART_LCR;
        pUart->MCR = pFPGA1_UART_MCR;
        pUart->LSR = pFPGA1_UART_LSR;
        pUart->MSR = pFPGA1_UART_MSR;
        pUart->SCR = pFPGA1_UART_SR;
    }
    else if(ch == 1)   //FPGA UART 2
    {
        pUart->RBR = pFPGA2_UART_RBR;
        pUart->THR = pFPGA2_UART_THR;
        pUart->DLL = pFPGA2_UART_DLL;
        pUart->DLM = pFPGA2_UART_DLM;
        pUart->IER = pFPGA2_UART_IER;
        pUart->IIR = pFPGA2_UART_IIR;
        pUart->FCR = pFPGA2_UART_FCR;
        pUart->LCR = pFPGA2_UART_LCR;
        pUart->MCR = pFPGA2_UART_MCR;
        pUart->LSR = pFPGA2_UART_LSR;
        pUart->MSR = pFPGA2_UART_MSR;
        pUart->SCR = pFPGA2_UART_SR;
    }
    else
    {
        return false;
    }

    //set up configuration
    pUart->IER->ALL = 0;	//disable interrupts

    //sticky
    if(pConfig->Sticky)
    {
        pUart->LCR->BIT.SP = 1;
        pUart->LCR->BIT.PEN = 1;
    }
    else
    {    
	    //parity
	    if(pConfig->Parity == ODD)
	    {
	        pUart->LCR->BIT.PEN = 1;
	        pUart->LCR->BIT.EPS = 0;
	    }
	    else if(pConfig->Parity == EVEN)
	    {
	        pUart->LCR->BIT.PEN = 1;
	        pUart->LCR->BIT.EPS = 1;
	    }
	    else
	    {
	        pUart->LCR->BIT.PEN = 0;
	    }
    }
    
    //data bits
    pUart->LCR->BIT.WLS = pConfig->DataBits;
    //stop bits
    pUart->LCR->BIT.STB = pConfig->StopBits;
    //break bit
    pUart->LCR->BIT.SB = 0;
    
    //baud rate
    //divisor = Fin / (Baudrate * 16)
    pUart->LCR->BIT.DLAB = 1;	//enable baud rate setting
    *pUart->DLL = FPGA_UART_BAUD_RATE_DIVISOR(pConfig->BaudRate) & 0xFF;
    *pUart->DLM = (FPGA_UART_BAUD_RATE_DIVISOR(pConfig->BaudRate) & 0xFF00) >> 8;
    pUart->LCR->BIT.DLAB = 0;	//disable baud rate setting
    
    //modem control register
    pUart->MCR->ALL = 0;
    
    //FIFO control register
    pUart->FCR->BIT.FIFOE = 1;		//enable FIFO
    pUart->FCR->BIT.RCVR_FIFOR = 1;	//reset receiver fifo
    pUart->FCR->BIT.XMIT_FIFOR = 1;	//reset transmitter fifo
    pUart->FCR->BIT.DMA_MS = 1;		//enable DMA
    pUart->FCR->BIT.RCVRT = pConfig->RxFifoLevel;	//receiver FIFO trigger level

    //enable Rx and Line Status interrupts
    pUart->IER->BIT.ERBFI = 1;
    pUart->IER->BIT.ELSI = 1;
    
	return true;
}

/*********************************************************************************************
* Function: UART_Read
*
* Desc: This function reads data from the FPGA UART up to the number of bytes required or till
*			the end of the bytes available.
*
* Params: FpgaUartCtrlStruct *pUart
*		int *pBuffer - the location to store data
*		int nBytes - number of byte to be read
*		int mark - mark of a packet
*
* Returns: int - the number of bytes read from the port. -1 means error had ocurred
*
* Notes: 
*
*********************************************************************************************/
int UART_Read(FpgaUartCtrlStruct *pUart, int *pBuffer, int nBytes, int mark)
{
    int temp;
    int nByteRead = 0;
    int *pDest;
    Uart16550LSRUnion lsr;
    bool markSearch;	//flag to indicate the period of mark searching

    //get a complete packet when FIFO receives all bytes of triggered level
    if (pUart->IIR->BIT.IP == 0)
    {
        switch (pUart->IIR->BIT.IIB2)
        {
            case IIR_RX_LINE_ERR:				//error occurred
			    //flush the fifo if error occurred, 
			    //but don't use the flush command, instead, read out the bytes one by one until the end
	            while (true)
	            {
	                lsr.ALL = pUart->LSR->ALL;	//reading the LSR resets the IIR
	                if(lsr.BIT.DR == 0)
			        {
			            break;
			        }
			        else
			        {
			            temp = *pUart->RBR;
			        }
	            }
				nByteRead = -1;	//discard any data
				break;
		
			case IIR_RX_DATA_READY:			//data ready
				do
			    {
			        //LSR updates with each word, it shall be read for each word
			        lsr.ALL = pUart->LSR->ALL;
					if (lsr.BIT.DR == 0)
			        {
			            break;		//exit if there is no more word in the FIFO
			        }
			        else
					{
					    //get valid data
					    if (mark != 0)
					    {
					        //mark is valid, so we need to look for the mark
						    if (nByteRead == 0)
						    {
						        //look for the mark byte
						        temp = *pUart->RBR & 0xFF;
						        if (temp == mark)
						        {
						            //we found the mark
						            pDest = pBuffer;
						            *pDest++ = temp;
						            nByteRead++;
						            markSearch = false;
						        }
						        else
						        {
						            markSearch = true;
						        }
						    }
						    else
						    {
						        //mark has been found, so save the next word
								*pDest++ = (*pUart->RBR & 0xFF);
							    nByteRead++;
						    }
					    }
					    else
					    {
					        //mark is null, so don't look for the mark
					        markSearch = false;
							*pDest++ = (*pUart->RBR & 0xFF);
						    nByteRead++;				        
					    }
					}
		    	}while (markSearch || (--nBytes > 0));
		    	//during the period of mark search, don't decrement the byte count, but use the markSearch flag
		    	
		    	break;
		    	
		    default:
		    	break;
        }
    }
   
    return nByteRead;
}

/*********************************************************************************************
* Function: UART_Write
*
* Desc: This function writes a series of bytes to UART
*
* Params: FpgaUartCtrlStruct *pUart
*		int *pBuffer - the location of data source
*		int nBytes - number of byte to be written
*
* Returns: int - the number of bytes written successfully
*
* Notes: 
*
*********************************************************************************************/
int FPGA_UART_Write(FpgaUartCtrlStruct *pUart, int *pBuffer, int nBytes)
{
    int nByteWritten = 0;
    int *pDest = pBuffer;
	int i;
	
	//wait for the currect transmission to complete
	while (pUart->LSR->BIT.THRE == 0);
	
	//send the packet one byte by one byte
	for(i = 0; i < nBytes; i++)
	{
		*pUart->THR = *pDest++;
		nByteWritten++;
		DSP_Delay(1);	//there must be some time delay between writes for FPGA UART to work properly
	}

	return nByteWritten;
}

/*********************************************************************************************
* Function: UART_Close
*
* Desc: This function disables the UART port
*
* Params: FpgaUartCtrlStruct *pUart - the port to be closed
*
* Returns: bool - true if it closes successfully
*
* Notes: 
*
*********************************************************************************************/
bool FPGA_UART_Close(FpgaUartCtrlStruct *pUart)
{
    //disable FIFO
    pUart->FCR->BIT.FIFOE = 0;
    	
    //disable Rx and Line Status interrupts
    pUart->IER->BIT.ERBFI = 0;
    pUart->IER->BIT.ELSI = 0;
    
    return true;
}