/**************************************************************************
*
* Copyright (C) 2005 Steve Karg <skarg@users.sourceforge.net>
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be included
* in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*
*********************************************************************/

#include <stdint.h>
#include <rtkernel.h>
#include <rtcom.h>
#include <itimer.h>
#include "mstp.h"

/* note: use the RTKernel-C API so that it can use this library */

#define RS485_IO_ENABLE(p)       ModemControl(p,0,DTR);
#define RS485_TRANSMIT_ENABLE(p) ModemControl(p,1,RTS);
#define RS485_RECEIVE_ENABLE(p)  ModemControl(p,0,RTS);

/* COM port number - COM1 = 0 */
static int RS485_Port = COM2;
/* baud rate */
static long RS485_Baud = 38400;
/* io base address */
static long RS485_Base = 0;
/* hardware IRQ number */
static long RS485_IRQ_Number = 0;

static void RS485_Standard_Port_Settings(long port, long *pIRQ,
    long *pBase)
{
    switch (port) {
    case COM1:
        *pBase = (long) 0x3F8;
        *pIRQ = 4L;
        break;
    case COM2:
        *pBase = (long) 0x2F8;
        *pIRQ = 3L;
        break;
    case COM3:
        *pBase = (long) 0x3E8;
        *pIRQ = 4L;
        break;
    case COM4:
        *pBase = (long) 0x2E8;
        *pIRQ = 3L;
        break;
    default:
        break;
    }
}

static RS485_Open_Port(int port,        /* COM port number - COM1 = 0 */
    long baud,                  /* baud rate */
    unsigned base,              /* io base address */
    int irq)
{                               /* hardware IRQ number */
    /* setup the COM IO */
    SetIOBase(port, base);
    SetIRQ(port, irq);

    if (irq < 8)
        RTKIRQTopPriority(irq, 9);

    InitPort(port, baud, PARITY_NONE, 1, 8);

    if (HasFIFO(port))
        EnableFIFO(port, 8);
    EnableCOMInterrupt(port, 1024 * 4);

    /* enable the 485 via the DTR pin */
    RS485_IO_ENABLE(port);
    RS485_RECEIVE_ENABLE(port);

    return;
}

void RS485_Initialize(void)
{
    RS485_Standard_Port_Settings(RS485_Port, &RS485_IRQ_Number,
        &RS485_Base);
    RS485_Open_Port(RS485_Port, RS485_Baud, RS485_Base, RS485_IRQ_Number);
}

void RS485_Send_Frame(volatile struct mstp_port_struct_t *mstp_port,    /* port specific data */
    uint8_t * buffer,           /* frame to send (up to 501 bytes of data) */
    uint16_t nbytes)
{                               /* number of bytes of data (up to 501) */
    bool status = true;         /* return value */

    (void) mstp_port;
    RS485_TRANSMIT_ENABLE(RS485_Port);
    SendBlock(RS485_Port, (char *) buffer, nbytes);
    /* need to wait at least 9600 baud * 512 bytes = 54mS */
    (void) WaitSendBufferEmpty(RS485_Port, MilliSecsToTicks(200));
    while (!(LineStatus(RS485_Port) & TX_SHIFT_EMPTY))
        RTKScheduler();
    RS485_RECEIVE_ENABLE(RS485_Port);

    return;
}

void RS485_Check_UART_Data(volatile struct mstp_port_struct_t *mstp_port)
{                               /* port specific data */
    COMData com_data = 0;       /* byte from COM driver */
    unsigned timeout = 10;      /* milliseconds to wait for a character */
    Duration ticks;             /* duration to wait for data */

    if (mstp_port->ReceiveError) {
        /* wait for state machine to clear this */
    }
    /* wait for state machine to read from the DataRegister */
    else if (!mstp_port->DataAvailable) {
        /* check for data */
        ticks = MilliSecsToTicks(timeout);
        if (!ticks)
            ticks = 1;
        if (RTKGetTimed(ReceiveBuffer[RS485_Port], &com_data, ticks)) {
            /* if error, */
            if (com_data & (COM_OVERRUN << 8))
                mstp_port->ReceiveError = true;
            else if (com_data & (COM_FRAME << 8))
                mstp_port->ReceiveError = true;
            else {
                mstp_port->DataRegister = com_data & 0x00FF;
                mstp_port->DataAvailable = true;
            }
        }
    }
}

void RS485_Process_Tx_Message(void)
{
    /* nothing to do */
}