path: root/c/src/lib/libbsp/powerpc/gen5200/mscan/mscan.c

/*===============================================================*\
| Project: RTEMS generic MPC5200 BSP                              |
+-----------------------------------------------------------------+
|                    Copyright (c) 2005                           |
|                    Embedded Brains GmbH                         |
|                    Obere Lagerstr. 30                           |
|                    D-82178 Puchheim                             |
|                    Germany                                      |
|                    rtems@embedded-brains.de                     |
+-----------------------------------------------------------------+
| The license and distribution terms for this file may be         |
| found in the file LICENSE in this distribution or at            |
|                                                                 |
| http://www.rtems.com/license/LICENSE.                           |
|                                                                 |
+-----------------------------------------------------------------+
| this file contains the MSCAN driver                             |
\*===============================================================*/

#include <stdio.h>
#include <stdlib.h>
#include <rtems.h>
#include <rtems/error.h>
#include <rtems/libio.h>
#include <string.h>
#include "../include/bsp.h"
#include "../irq/irq.h"
#include "../include/mpc5200.h"
#include "mscan.h"

/* #define MSCAN_LOOPBACK */

volatile uint32_t tx_int_wr_count = 0;

struct mpc5200_rx_cntrl mpc5200_mscan_rx_cntrl[MPC5200_CAN_NO];
static struct mscan_channel_info chan_info[MPC5200_CAN_NO];

/* time segmant table  */
uint8_t can_time_segment_table[CAN_MAX_NO_OF_TQ - MIN_NO_OF_TQ + 1][NO_OF_TABLE_ENTRIES] = {

/* Total no. of time quantas */   /* Time Segment 1*/    /* Time Segment 2 */     /* Sync: Jump width */
{         7,                                4,                     2,                       1          },
{         8,                                5,                     2,                       1          },
{         9,                                6,                     2,                       2          },
{        10,                                6,                     3,                       2          },
{        11,                                7,                     3,                       2          },
{        12,                                8,                     3,                       2          },
{        13,                                8,                     4,                       2          },
{        14,                                9,                     4,                       2          },
{        15,                               10,                     4,                       2          },
{        16,                               10,                     5,                       2          },
{        17,                               11,                     5,                       2          },
{        18,                               12,                     5,                       2          },
{        19,                               12,                     6,                       2          },
{        20,                               13,                     6,                       2          },
{        21,                               14,                     6,                       2          },
{        22,                               14,                     7,                       2          },
{        23,                               15,                     7,                       2          },
{        24,                               15,                     8,                       2          },
{        25,                               16,                     8,                       2          }};


/*
 * MPC5x00 MSCAN tx ring buffer function to get a can message buffer from the head of the tx ring buffer
 */
static struct can_message * get_tx_buffer(struct mscan_channel_info *chan)
  {
  /* define a temp. mess ptr. */
  struct can_message * tmp_mess_ptr = NULL, *temp_head_ptr;

  /* set temp. head pointer */
  temp_head_ptr = chan->tx_ring_buf.head_ptr;

  /* check buffer empty condition */
  if(temp_head_ptr != chan->tx_ring_buf.tail_ptr)
    {

    /* current buffer head. ptr. */
    tmp_mess_ptr = temp_head_ptr;

    /* increment the head pointer */
    temp_head_ptr++;

    /* check for wrap around condition */
    if(temp_head_ptr > chan->tx_ring_buf.buf_ptr + NO_OF_MSCAN_TX_BUFF)
      {

      /* set head ptr. to the begin of the ring buffer */
      temp_head_ptr = chan->tx_ring_buf.buf_ptr;

      }

    /* end of crtical section restore head ptr. */
    chan->tx_ring_buf.head_ptr = temp_head_ptr;
    }

  /* return the current head pointer */
  return tmp_mess_ptr;
  }

/*
 * MPC5x00 MSCAN tx ring buffer function to write a can message buffer to the tail of the tx ring buffer
 */
static struct can_message * fill_tx_buffer(struct mscan_channel_info *chan, struct can_message * mess_ptr)
  {
  /* define a temp. mess ptr. to the entry which follows the current tail entry */
  struct can_message * tmp_mess_ptr = chan->tx_ring_buf.tail_ptr + 1;

  /* check for the wrap around condition */
  if(tmp_mess_ptr >  chan->tx_ring_buf.buf_ptr + NO_OF_MSCAN_TX_BUFF)
    {
	/* set temp. mess. ptr to the begin of the ring buffer */
	tmp_mess_ptr = chan->tx_ring_buf.buf_ptr;
    }

  /* check buffer full condition */
  if(tmp_mess_ptr == chan->tx_ring_buf.head_ptr)
    {
	/* return NULL in case buffer is full */
  	return NULL;
    }
  else
    {
	/* copy the can mess. to the tail of the buffer */
    memcpy((void *)chan->tx_ring_buf.tail_ptr, (void *)mess_ptr, sizeof(struct can_message));

    /* set new tail equal to temp. mess. ptr. */
    chan->tx_ring_buf.tail_ptr = tmp_mess_ptr;
    }

  /* return the actual tail ptr. (next free entry) */
  return chan->tx_ring_buf.tail_ptr;
  }

/*
 * MPC5x00 MSCAN interrupt handler
 */
static void mpc5200_mscan_interrupt_handler(rtems_irq_hdl_param handle)
  {
  rtems_status_code status;
  mscan_handle *mscan_hdl = (mscan_handle *)handle;
  struct mscan_channel_info *chan = &chan_info[mscan_hdl->mscan_channel];
  struct can_message rx_mess, *rx_mess_ptr, *tx_mess_ptr;
  volatile struct mpc5200_mscan *mscan = chan->regs;
  register uint8_t idx;

  /*
   handle tx ring buffer
   */

  /* loop over all 3 tx buffers */
  for(idx = TFLG_TXE0; idx <= TFLG_TXE2; idx=idx<<1)
    {

    /* check for tx buffer vacation */
    if((mscan->tflg) & idx)
      {

      /* try to get a message */
      tx_mess_ptr = get_tx_buffer(chan);

      /* check for new tx message */
      if(tx_mess_ptr != NULL)
        {

        /* select the tx buffer */
        mscan->bsel  = idx;

        /* check for toucan interface */
        if((mscan_hdl->toucan_callback) == NULL)
          {

          /* set tx id */
		  mscan->txidr0 = SET_IDR0(tx_mess_ptr->mess_id);
		  mscan->txidr1 = SET_IDR1(tx_mess_ptr->mess_id);
		  mscan->txidr2 = 0;
          mscan->txidr3 = 0;

          /* insert dlc into mscan register */
		  mscan->txdlr = (uint8_t)((tx_mess_ptr->mess_len) & 0x000F);
	      }

        /* select one free tx buffer if TOUCAN not registered) */
        if(((mscan_hdl->toucan_callback) == NULL) || (((mscan_hdl->toucan_callback) != NULL) && ((tx_mess_ptr->toucan_tx_id) == idx)))
          {

          /* set tx id */
		  mscan->txidr0 = SET_IDR0(tx_mess_ptr->mess_id);
		  mscan->txidr1 = SET_IDR1(tx_mess_ptr->mess_id);
		  mscan->txidr2 = 0;
          mscan->txidr3 = 0;

          /* insert dlc into mscan register */
		  mscan->txdlr = (uint8_t)((tx_mess_ptr->mess_len) & 0x000F);

          /* copy tx data to MSCAN registers */
          switch(mscan->txdlr)
            {
            case 8:
              mscan->txdsr7 = tx_mess_ptr->mess_data[7];
            case 7:
              mscan->txdsr6 = tx_mess_ptr->mess_data[6];
            case 6:
              mscan->txdsr5 = tx_mess_ptr->mess_data[5];
            case 5:
              mscan->txdsr4 = tx_mess_ptr->mess_data[4];
            case 4:
              mscan->txdsr3 = tx_mess_ptr->mess_data[3];
            case 3:
              mscan->txdsr2 = tx_mess_ptr->mess_data[2];
            case 2:
              mscan->txdsr1 = tx_mess_ptr->mess_data[1];
            case 1:
              mscan->txdsr0 = tx_mess_ptr->mess_data[0];
              break;
            default:
              break;
            }

          /* enable message buffer specific interrupt */
	      mscan->tier |= mscan->bsel;

	      /* start transfer */
          mscan->tflg = mscan->bsel;

          /* release counting semaphore of tx ring buffer */
	 	  rtems_semaphore_release((rtems_id)(chan->tx_rb_sid));

	 	  tx_int_wr_count++;

          }
        else
          {

          /* refill the tx ring buffer with the message */
          fill_tx_buffer(chan, tx_mess_ptr);

	      }
	    }
	  else
	    {
		/* reset interrupt enable bit */
	    mscan->tier &= ~(idx);
	    }
      }
    }

  /*
   handle rx interrupts
   */

  /* check for rx interrupt source */
  if(mscan->rier & RIER_RXFIE)
    {

    /* can messages received ? */
    while(mscan->rflg & RFLG_RXF)
      {

      if(mscan_hdl->toucan_callback == NULL)
        {

        /* select temporary rx buffer */
        rx_mess_ptr = &rx_mess;

        }
      else
        {

        /* check the rx fliter-match indicators (16-bit filter mode) */
        /* in case of more than one hit, lower hit has priority */
	  idx = (mscan->idac) & 0x7;
	  switch(idx)
          {

          case 0:
	  case 1:
     	  case 2:
  	  case 3:
            rx_mess_ptr =
	      (struct can_message *)&(mpc5200_mscan_rx_cntrl[mscan_hdl->mscan_channel].can_rx_message[idx]);
            break;

          /* this case should never happen */
		  default:
            /* reset the rx indication flag */
            mscan->rflg |= RFLG_RXF;

            return;
            break;
	      }

        }

      /* get rx ID */
      rx_mess_ptr->mess_id = GET_IDR0(mscan->rxidr0) | GET_IDR1(mscan->rxidr1);

      /* get rx len */
      rx_mess_ptr->mess_len = ((mscan->rxdlr) & 0x0F);

      /* get time stamp */
      rx_mess_ptr->mess_time_stamp = ((mscan->rxtimh << 8) | (mscan->rxtiml));

      /* get the data */
	  switch(rx_mess_ptr->mess_len)
	    {

	    case 8:
	      rx_mess_ptr->mess_data[7] = mscan->rxdsr7;
	    case 7:
	      rx_mess_ptr->mess_data[6] = mscan->rxdsr6;
	    case 6:
	      rx_mess_ptr->mess_data[5] = mscan->rxdsr5;
	    case 5:
	      rx_mess_ptr->mess_data[4] = mscan->rxdsr4;
	    case 4:
	      rx_mess_ptr->mess_data[3] = mscan->rxdsr3;
	    case 3:
	      rx_mess_ptr->mess_data[2] = mscan->rxdsr2;
	    case 2:
	      rx_mess_ptr->mess_data[1] = mscan->rxdsr1;
	    case 1:
	      rx_mess_ptr->mess_data[0] = mscan->rxdsr0;
	    case 0:
	    default:
	      break;

	    }

      if(mscan_hdl->toucan_callback == NULL)
        {

        if((status = rtems_message_queue_send(chan->rx_qid, (void *)rx_mess_ptr, sizeof(struct can_message))) != RTEMS_SUCCESSFUL)
		  {

		  chan->int_rx_err++;

          }

	    }
      else
        {

        mscan_hdl->toucan_callback((int16_t)(((mscan->idac) & 0x7) + 3));

	    }

      /* reset the rx indication flag */
      mscan->rflg |= RFLG_RXF;

      } /* end of while(mscan->rflg & RFLG_RXF) */

    }

    /* status change detected */
    if(mscan->rflg & RFLG_CSCIF)
      {

      mscan->rflg |= RFLG_CSCIF;

      if(mscan_hdl->toucan_callback != NULL)
        {

        mscan_hdl->toucan_callback((int16_t)(-1));

        }

      }

  }


/*
 * Disable MSCAN ints.
 */
void mpc5200_mscan_int_disable(volatile struct mpc5200_mscan *mscan)
  {

  /* RX Interrupt Enable on MSCAN_A/_B -----------------------------*/
  /*    [07]:WUPIE         0 : WakeUp interrupt disabled            */
  /*    [06]:CSCIE         0 : Status Change interrupt disabled     */
  /*    [05]:RSTATE1       0 : Recv. Status Change int. ,Bit 1      */
  /*    [04]:RSTATE0       0 : Recv. Status Change int. ,Bit 0      */
  /*                           -> 00 rx status change int. disabled */
  /*    [03]:TSTAT1        0 : Transmit. Status Change int. , Bit 1 */
  /*    [02]:TSTAT0        0 : Transmit. Status Change int. , Bit 0 */
  /*                           -> 00 tx status change int. disabled */
  /*    [01]:OVRIE         0 : Overrun Interrupt is disabled        */
  /*    [00]:RXFIE         0 : Recv. Full interrupt is disabled     */
  mscan->rier &= ~(RIER_CSCIE | RIER_RXFIE);

  /* TX Interrupt Enable on MSCAN_A/_B -----------------------------*/
  /*    [07]:res.          0 : reserved                             */
  /*    [06]:res.          0 : reserved                             */
  /*    [05]:res.          0 : reserved                             */
  /*    [04]:res.          0 : reserved                             */
  /*    [03]:res.          0 : reserved                             */
  /*    [02]:TSEG12        0 : TX2message buffer int. is disabled   */
  /*    [01]:TSEG11        0 : TX1 message buffer int. is disabled  */
  /*    [00]:TSEG10        0 : TX0 message buffer int. is disabled  */
  mscan->tier &= ~(TIER_TXEI2 | TIER_TXEI1 | TIER_TXEI0);

  return;

  }


/*
 * Enable MSCAN ints.
 */
void mpc5200_mscan_int_enable(volatile struct mpc5200_mscan *mscan)
  {

  /* RX Interrupt Enable on MSCAN_A/_B -----------------------------*/
  /*    [07]:WUPIE         0 : WakeUp interrupt disabled            */
  /*    [06]:CSCIE         1 : Status Change interrupt enabled      */
  /*    [05]:RSTATE1       0 : Recv. Status Change int. ,Bit 1      */
  /*    [04]:RSTATE0       1 : Recv. Status Change int. ,Bit 0      */
  /*                           -> 01 BusOff status changes enabled  */
  /*    [03]:TSTAT1        0 : Transmit. Status Change int. , Bit 1 */
  /*    [02]:TSTAT0        1 : Transmit. Status Change int. , Bit 0 */
  /*                           -> 01 BusOff status changes enabled  */
  /*    [01]:OVRIE         0 : Overrun Interrupt is disabled        */
  /*    [00]:RXFIE         1 : Recv. Full interrupt is enabled      */
  mscan->rier |= (RIER_CSCIE  | RIER_RXFIE | RIER_RSTAT(1) | RIER_TSTAT(1));

  return;

  }

/*
 * Unmask MPC5x00 MSCAN_A interrupts
 */
void mpc5200_mscan_a_on(const rtems_irq_connect_data* ptr)
  {
  volatile struct mpc5200_mscan *mscan = (&chan_info[MSCAN_A])->regs;

  mpc5200_mscan_int_enable(mscan);

  return;

  }


/*
 * Mask MPC5x00 MSCAN_A interrupts
 */
void mpc5200_mscan_a_off(const rtems_irq_connect_data* ptr)
  {
  volatile struct mpc5200_mscan *mscan = (&chan_info[MSCAN_A])->regs;

  mpc5200_mscan_int_disable(mscan);

  return;

  }


/*
 *  Get MSCAN_A interrupt mask setting
 */
int mpc5200_mscan_a_isOn(const rtems_irq_connect_data* ptr)
  {
  volatile struct mpc5200_mscan *mscan = (&chan_info[MSCAN_A])->regs;

  if((mscan->rier & RIER_CSCIE) && (mscan->rier & RIER_RXFIE))
    return RTEMS_SUCCESSFUL;
  else
    return RTEMS_UNSATISFIED;

  return RTEMS_SUCCESSFUL;

  }


/*
 * Unmask MPC5x00 MSCAN_B interrupts
 */
void mpc5200_mscan_b_on(const rtems_irq_connect_data* ptr)
  {
  volatile struct mpc5200_mscan *mscan = (&chan_info[MSCAN_B])->regs;

  mpc5200_mscan_int_enable(mscan);

  return;

  }


/*
 * Mask MPC5x00 MSCAN_B interrupts
 */
void mpc5200_mscan_b_off(const rtems_irq_connect_data* ptr)
  {
  volatile struct mpc5200_mscan *mscan = (&chan_info[MSCAN_B])->regs;

  mpc5200_mscan_int_disable(mscan);

  return;

  }


/*
 *  Get MSCAN_B interrupt mask setting
 */
int mpc5200_mscan_b_isOn(const rtems_irq_connect_data* ptr)
  {
  volatile struct mpc5200_mscan *mscan = (&chan_info[MSCAN_B])->regs;

  if((mscan->rier & RIER_CSCIE) && (mscan->rier & RIER_RXFIE))
    return RTEMS_SUCCESSFUL;
  else
    return RTEMS_UNSATISFIED;

  return RTEMS_SUCCESSFUL;

  }

static mscan_handle mscan_a_handle =
  {
  MSCAN_A,
  NULL
  };


static mscan_handle mscan_b_handle =
  {
  MSCAN_B,
  NULL
  };

/*
 * MPC5x00 MSCAN_A/_B irq data
 */
static rtems_irq_connect_data mpc5200_mscan_irq_data[MPC5200_CAN_NO] =
  {{
  BSP_SIU_IRQ_MSCAN1,
  (rtems_irq_hdl) mpc5200_mscan_interrupt_handler,
  (rtems_irq_hdl_param) &mscan_a_handle,
  (rtems_irq_enable) mpc5200_mscan_a_on,
  (rtems_irq_disable) mpc5200_mscan_a_off,
  (rtems_irq_is_enabled) mpc5200_mscan_a_isOn
  },
  {
  BSP_SIU_IRQ_MSCAN2,
  (rtems_irq_hdl) mpc5200_mscan_interrupt_handler,
  (rtems_irq_hdl_param) &mscan_b_handle,
  (rtems_irq_enable) mpc5200_mscan_b_on,
  (rtems_irq_disable) mpc5200_mscan_b_off,
  (rtems_irq_is_enabled) mpc5200_mscan_b_isOn
  }};


/*
 * Enter MSCAN sleep mode
 */
void mpc5200_mscan_enter_sleep_mode(volatile struct mpc5200_mscan *mscan)
  {

  /* Control Register 0 --------------------------------------------*/
  /*    [07]:RXFRM       0 : Recv. Frame, Flag Bit (rd.&clear only) */
  /*    [06]:RXACT       0 : Recv. Active, Status Bit (rd. only)    */
  /*    [05]:CSWAI       0 : CAN Stops in Wait Mode                 */
  /*    [04]:SYNCH       0 : Synchronized, Status Bit (rd. only)    */
  /*    [03]:TIME        1 : Generate Timestamps                    */
  /*    [02]:WUPE        1 : WakeUp Enabled                         */
  /*    [01]:SLPRQ    0->1 : Sleep Mode Request                     */
  /*    [00]:INITRQ      0 : No init. Mode Request                  */
  /* select sleep mode */
  mscan->ctl0 |= (CTL0_SLPRQ);

  /* Control Register 1 --------------------------------------------*/
  /*    [07]:CANE        0 : MSCAN Module is disabled               */
  /*    [06]:CLKSRC      1 : Clock Source -> IPB-Clock (33 MHz)     */
  /*    [05]:LOOPB       0 : No Loopback                            */
  /*    [04]:LISTEN      0 : Normal Operation                       */
  /*    [03]:res         0 : reserved                               */
  /*    [02]:WUPM        0 : No protect. from spurious WakeUp       */
  /*    [01]:SLPAK    0->1 : Sleep Mode Acknowledge (rd. only)      */
  /*    [00]:INITAK      0 : Init. Mode Acknowledge (rd. only)      */
  /* wait for sleep mode acknowledge */
  while(!(mscan->ctl1 & CTL1_SLPAK));

  return;

  }


/*
 * Exit MSCAN sleep mode
 */
void mpc5200_mscan_exit_sleep_mode(volatile struct mpc5200_mscan *mscan)
  {

  /* Control Register 0 --------------------------------------------*/
  /*    [07]:RXFRM       0 : Recv. Frame, Flag Bit (rd.&clear only) */
  /*    [06]:RXACT       0 : Recv. Active, Status Bit (rd. only)    */
  /*    [05]:CSWAI       0 : CAN Stops in Wait Mode                 */
  /*    [04]:SYNCH       0 : Synchronized, Status Bit (rd. only)    */
  /*    [03]:TIME        1 : Generate Timestamps                    */
  /*    [02]:WUPE        1 : WakeUp Enabled                         */
  /*    [01]:SLPRQ    0->1 : Sleep Mode Request                     */
  /*    [00]:INITRQ      0 : No init. Mode Request                  */
  /* select sleep mode */
  mscan->ctl0 &= ~(CTL0_SLPRQ);

  /* Control Register 1 --------------------------------------------*/
  /*    [07]:CANE        0 : MSCAN Module is disabled               */
  /*    [06]:CLKSRC      1 : Clock Source -> IPB-Clock (33 MHz)     */
  /*    [05]:LOOPB       0 : No Loopback                            */
  /*    [04]:LISTEN      0 : Normal Operation                       */
  /*    [03]:res         0 : reserved                               */
  /*    [02]:WUPM        0 : No protect. from spurious WakeUp       */
  /*    [01]:SLPAK    0->1 : Sleep Mode Acknowledge (rd. only)      */
  /*    [00]:INITAK      0 : Init. Mode Acknowledge (rd. only)      */
  /* wait for sleep mode acknowledge */
  while((mscan->ctl1 & CTL1_SLPAK));

  return;

  }


/*
 * Enter MSCAN init mode and disconnect from bus
 */
void mpc5200_mscan_enter_init_mode(volatile struct mpc5200_mscan *mscan)
  {

  /* Control Register 0 --------------------------------------------*/
  /*    [07]:RXFRM       0 : Recv. Frame, Flag Bit (rd.&clear only) */
  /*    [06]:RXACT       0 : Recv. Active, Status Bit (rd. only)    */
  /*    [05]:CSWAI       0 : CAN Stops in Wait Mode                 */
  /*    [04]:SYNCH       0 : Synchronized, Status Bit (rd. only)    */
  /*    [03]:TIME        1 : Generate Timestamps                    */
  /*    [02]:WUPE        0 : WakeUp disabled                        */
  /*    [01]:SLPRQ       0 : No Sleep Mode Request                  */
  /*    [00]:INITRQ   0->1 : Init. Mode Request                     */
  /* select init mode */
  mscan->ctl0 |= (CTL0_INITRQ);

  /* Control Register 1 --------------------------------------------*/
  /*    [07]:CANE        0 : MSCAN Module is disabled               */
  /*    [06]:CLKSRC      1 : Clock Source -> IPB-Clock (33 MHz)     */
  /*    [05]:LOOPB       0 : No Loopback                            */
  /*    [04]:LISTEN      0 : Normal Operation                       */
  /*    [03]:res         0 : reserved                               */
  /*    [02]:WUPM        0 : No protect. from spurious WakeUp       */
  /*    [01]:SLPAK       0 : Sleep Mode Acknowledge (rd. only)      */
  /*    [00]:INITAK   0->1 : Init. Mode Acknowledge (rd. only)      */
  /* wait for init mode acknowledge */
  while(!(mscan->ctl1 & CTL1_INITAK));

  return;

  }


/*
 * Exit MSCAN init mode
 */
void mpc5200_mscan_exit_init_mode(volatile struct mpc5200_mscan *mscan)
  {

  /* Control Register 0 --------------------------------------------*/
  /*    [07]:RXFRM       0 : Recv. Frame, Flag Bit (rd.&clear only) */
  /*    [06]:RXACT       0 : Recv. Active, Status Bit (rd. only)    */
  /*    [05]:CSWAI       0 : CAN Stops in Wait Mode                 */
  /*    [04]:SYNCH       0 : Synchronized, Status Bit (rd. only)    */
  /*    [03]:TIME        1 : Generate Timestamps                    */
  /*    [02]:WUPE        0 : WakeUp Disabled                        */
  /*    [01]:SLPRQ       0 : No Sleep Mode Request                  */
  /*    [00]:INITRQ   1->0 : Init. Mode Request                     */
  /* select normal mode */
  mscan->ctl0 &= ~(CTL0_INITRQ);

  /* Control Register 1 --------------------------------------------*/
  /*    [07]:CANE        0 : MSCAN Module is disabled               */
  /*    [06]:CLKSRC      1 : Clock Source -> IPB-Clock (33 MHz)     */
  /*    [05]:LOOPB       0 : No Loopback                            */
  /*    [04]:LISTEN      0 : Normal Operation                       */
  /*    [03]:res         0 : reserved                               */
  /*    [02]:WUPM        0 : No protect. from spurious WakeUp       */
  /*    [01]:SLPAK       0 : Sleep Mode Acknowledge (rd. only)      */
  /*    [00]:INITAK   1->0 : Init. Mode Acknowledge (rd. only)      */
  /* wait for normal mode acknowledge */
  while(mscan->ctl1 & CTL1_INITAK);

  return;

  }


/*
 * MPC5x00 MSCAN wait for sync. with CAN bus
 */
void mpc5200_mscan_wait_sync(volatile struct mpc5200_mscan *mscan)
  {

  /* Control Register 0 --------------------------------------------*/
  /*    [07]:RXFRM       0 : Recv. Frame, Flag Bit (rd.&clear only) */
  /*    [06]:RXACT       0 : Recv. Active, Status Bit (rd. only)    */
  /*    [05]:CSWAI       0 : CAN Stops in Wait Mode                 */
  /*    [04]:SYNCH    0->1 : Synchronized, Status Bit (rd. only)    */
  /*    [03]:TIME        1 : Generate Timestamps                    */
  /*    [02]:WUPE        0 : WakeUp Disabled                        */
  /*    [01]:SLPRQ       0 : No Sleep Mode Request                  */
  /*    [00]:INITRQ      0 : No init. Mode Request                  */
  /* wait for MSCAN A_/_B bus synch. */

#if 0 /* we don't have a need to wait for sync. */
  while(!((mscan->ctl0) & CTL0_SYNCH));
#endif
  return;

  }

/* calculate the can clock prescaler value */
uint8_t prescaler_calculation(uint32_t can_bit_rate, uint32_t can_clock_frq, uint8_t *tq_no) {

/* local variables */
uint8_t presc_val, tq_no_dev_min = 0;
uint32_t bit_rate, bit_rate_dev, frq_tq, bit_rate_dev_min = 0xFFFFFFFF;

/* loop through all values of time quantas */
for(*tq_no = CAN_MAX_NO_OF_TQ; *tq_no >= MIN_NO_OF_TQ; (*tq_no)--) {

  /* calculate time quanta freq. */
  frq_tq = *tq_no * can_bit_rate;

  /* calculate the optimized prescal. val. */
  presc_val = (can_clock_frq+frq_tq/2)/frq_tq;

  /* calculate the bitrate */
  bit_rate = can_clock_frq/(*tq_no * presc_val);

  /* calculate the bitrate deviation */
  if(can_bit_rate >= bit_rate)
    {
    /* calculate the bitrate deviation */
    bit_rate_dev = can_bit_rate - bit_rate;
    }
  else
    {
    /* calculate the bitrate deviation */
    bit_rate_dev = bit_rate - can_bit_rate;
    }

  /* check the deviation freq. */
  if(bit_rate_dev == 0) {

    /* return if best match (zero deviation) */
   return (uint8_t)(presc_val);
    }
  else
    {

    /* check for minimum of bit rate deviation */
    if(bit_rate_dev < bit_rate_dev_min) {

      /* recognize the minimum freq. deviation */
      bit_rate_dev_min = bit_rate_dev;

      /* recognize the no. of time quantas */
      tq_no_dev_min = *tq_no;
	  }
	}
  }

  /* get the no of tq's */
  *tq_no = tq_no_dev_min;

  /* calculate time quanta freq. */
  frq_tq = *tq_no * can_bit_rate;

  /* return the optimized prescaler value */
  return (uint8_t)((can_clock_frq+frq_tq/2)/frq_tq);
}

/*
 * MPC5x00 MSCAN set up the bit timing
 */
void mpc5200_mscan_perform_bit_time_settings(volatile struct mpc5200_mscan *mscan, uint32_t can_bit_rate, uint32_t can_clock_frq)
{
  uint32_t prescale_val = 0;
  uint8_t tq_no, tseg_1, tseg_2, sseg;

  /* get optimized prescaler value */
  prescale_val = prescaler_calculation(can_bit_rate, can_clock_frq, &tq_no);

  /* get time segment length from time segment table */
  tseg_1 = can_time_segment_table[tq_no - MIN_NO_OF_TQ][TSEG_1];
  tseg_2 = can_time_segment_table[tq_no - MIN_NO_OF_TQ][TSEG_2];
  sseg    = can_time_segment_table[tq_no - MIN_NO_OF_TQ][SJW];

  /* Bus Timing Register 0 MSCAN_A/_B ------------------------------*/
  /*    [07]:SJW1        1 : Synchronization jump width, Bit1       */
  /*    [06]:SJW0        0 : Synchronization jump width, Bit0       */
  /*                         SJW = 2 -> 3 Tq clock cycles           */
  /*    [05]:BRP5        0 : Baud Rate Prescaler, Bit 5             */
  /*    [04]:BRP4        0 : Baud Rate Prescaler, Bit 4             */
  /*    [03]:BRP3        0 : Baud Rate Prescaler, Bit 3             */
  /*    [02]:BRP2        1 : Baud Rate Prescaler, Bit 2             */
  /*    [01]:BRP1        0 : Baud Rate Prescaler, Bit 1             */
  /*    [00]:BRP0        1 : Baud Rate Prescaler, Bit 0             */
  mscan->btr0 = (BTR0_SJW(sseg-1) | BTR0_BRP(prescale_val-1));

  /* Bus Timing Register 1 MSCAN_A/_B ------------------------------*/
  /*    [07]:SAMP        0 : One Sample per bit                     */
  /*    [06]:TSEG22      0 : Time Segment 2, Bit 2                  */
  /*    [05]:TSEG21      1 : Time Segment 2, Bit 1                  */
  /*    [04]:TSEG20      0 : Time Segment 2, Bit 0                  */
  /*                         -> PHASE_SEG2 = 3 Tq                   */
  /*    [03]:TSEG13      0 : Time Segment 1, Bit 3                  */
  /*    [02]:TSEG12      1 : Time Segment 1, Bit 2                  */
  /*    [01]:TSEG11      1 : Time Segment 1, Bit 1                  */
  /*    [00]:TSEG10      0 : Time Segment 1, Bit 0                  */
  mscan->btr1 =  (BTR1_TSEG_22_20(tseg_2-1) | BTR1_TSEG_13_10(tseg_1-1));

  return;

  }


/*
 * MPC5x00 MSCAN perform settings in init mode
 */
void mpc5200_mscan_perform_init_mode_settings(volatile struct mpc5200_mscan *mscan)
  {

  /* perform all can bit time settings */
  mpc5200_mscan_perform_bit_time_settings(mscan,CAN_BIT_RATE,IPB_CLOCK);

  /* Control Register 1 --------------------------------------------*/
  /*    [07]:CANE        0 : MSCAN Module is disabled               */
  /*    [06]:CLKSRC      0 : Clock Source -> IPB_CLOCK (bsp.h)      */
  /*    [05]:LOOPB       0 : No Loopback                            */
  /*    [04]:LISTEN      0 : Normal Operation                       */
  /*    [03]:res         0 : reserved                               */
  /*    [02]:WUPM        0 : No protect. from spurious WakeUp       */
  /*    [01]:SLPAK    1->0 : Sleep Mode Acknowledge (rd. only)      */
  /*    [00]:INITAK      0 : Init. Mode Acknowledge (rd. only)      */
  /* Set CLK source, disable loopback & listen-only mode */
#ifndef MSCAN_LOOPBACK
  mscan->ctl1 &= ~(CTL1_LISTEN | CTL1_LOOPB | CTL1_CLKSRC);
#else
  mscan->ctl1 &= ~(CTL1_LISTEN | CTL1_CLKSRC);
  mscan->ctl1 |=  (CTL1_LOOPB);
#endif

  /* IPB clock                  -> IPB_CLOCK (bsp.h)                                                    */
  /* bitrate                    -> CAN_BIT_RATE (mscan.h)                                               */
  /* Max. no of Tq              -> CAN_MAX_NO_OF_TQ (mscan.h)                                           */
  /* Prescaler value            -> prescale_val = ROUND_UP(IPB_CLOCK/(CAN_BIT_RATE * CAN_MAX_NO_OF_TQ)) */
  /* SYNC_SEG                   ->  1 tq                                                                */
  /* time segment 1             -> 16 tq (PROP_SEG+PHASE_SEG), CAN_MAX_NO_OF_TQ_TSEG1 = 15 (mscan.h)    */
  /* time segment 2             ->  8 tq (PHASE_SEG2)        , CAN_MAX_NO_OF_TQ_TSEG2 =  7 (mscan.h)    */
  /* SJW                        ->  3 (fixed 0...3)          , CAN_MAX_NO_OF_TQ_SJW   =  2 (mscan.h)    */

  /* ID Acceptance Control MSCAN_A/_B ------------------------------*/
  /*    [07]:res.        0 : reserved                               */
  /*    [06]:res.        0 : reserved                               */
  /*    [05]:IDAM1       0 : ID acceptance control, Bit1            */
  /*    [04]:IDAM0       1 : ID acceptance control, Bit0            */
  /*                         -> filter 16 bit mode                  */
  /*    [03]:res.        0 : reserved                               */
  /*    [02]:IDHIT2      0 : ID acceptance hit indication, Bit 2    */
  /*    [01]:IDHIT1      0 : ID acceptance hit indication, Bit 1    */
  /*    [00]:IDHIT0      0 : ID acceptance hit indication, Bit 0    */
  mscan->idac &= ~(IDAC_IDAM1);
  mscan->idac |=  (IDAC_IDAM0);

  /* initialize rx filter masks (16 bit) */
  mscan->idmr0  = SET_IDMR0(0x07FF);
  mscan->idmr1  = SET_IDMR1(0x07FF);
  mscan->idmr2  = SET_IDMR2(0x07FF);
  mscan->idmr3  = SET_IDMR3(0x07FF);
  mscan->idmr4  = SET_IDMR4(0x07FF);
  mscan->idmr5  = SET_IDMR5(0x07FF);
  mscan->idmr6  = SET_IDMR6(0x07FF);
  mscan->idmr7  = SET_IDMR7(0x07FF);

  /* Control Register 1 --------------------------------------------*/
  /*    [07]:CANE     0->1 : MSCAN Module is enabled                */
  /*    [06]:CLKSRC      1 : Clock Source -> IPB_CLOCK (bsp.h)      */
  /*    [05]:LOOPB       0 : No Loopback                            */
  /*    [04]:LISTEN      0 : Normal Operation                       */
  /*    [03]:res         0 : reserved                               */
  /*    [02]:WUPM        0 : No protect. from spurious WakeUp       */
  /*    [01]:SLPAK       0 : Sleep Mode Acknowledge (rd. only)      */
  /*    [00]:INITAK      0 : Init. Mode Acknowledge (rd. only)      */
  /* enable MSCAN A_/_B */
  mscan->ctl1 |= (CTL1_CANE);

  return;

  }


/*
 * MPC5x00 MSCAN perform settings in normal mode
 */
void mpc5200_mscan_perform_normal_mode_settings(volatile struct mpc5200_mscan *mscan)
  {

  /* Control Register 0 --------------------------------------------*/
  /*    [07]:RXFRM       0 : Recv. Frame, Flag Bit (rd.&clear only) */
  /*    [06]:RXACT       0 : Recv. Active, Status Bit (rd. only)    */
  /*    [05]:CSWAI       0 : CAN Stops in Wait Mode                 */
  /*    [04]:SYNCH       0 : Synchronized, Status Bit (rd. only)    */
  /*    [03]:TIME        1 : Generate Timestamps                    */
  /*    [02]:WUPE        0 : WakeUp Disabled                        */
  /*    [01]:SLPRQ       0 : No Sleep Mode Request                  */
  /*    [00]:INITRQ      0 : No init. Mode Request                  */
  /* Disable wait mode, enable timestamps */
  mscan->ctl0 &= ~(CTL0_CSWAI);
  mscan->ctl0 |=  (CTL0_TIME);

  return;

  }

rtems_status_code mpc5200_mscan_set_mode(rtems_device_minor_number minor, uint8_t mode)
  {
  struct mscan_channel_info *chan = NULL;
  volatile struct mpc5200_mscan *mscan     = NULL;

  switch(minor)
    {

    case MSCAN_A:
    case MSCAN_B:
      chan  = &chan_info[minor];
      mscan = chan->regs;
      break;

    default:
      return RTEMS_UNSATISFIED;
      break;
    }

  if(chan->mode == mode)
    return RTEMS_SUCCESSFUL;

  switch(mode)
    {

    case MSCAN_INIT_NORMAL_MODE:
      /* if not already set enter init mode */
	  mpc5200_mscan_enter_init_mode(mscan);
	  /* perform initialization which has to be done in init mode */
      mpc5200_mscan_perform_init_mode_settings(mscan);
      break;

    case MSCAN_NORMAL_MODE:
      /* if not already set enter init mode */
      mpc5200_mscan_enter_init_mode(mscan);

      if((chan->mode) == MSCAN_INITIALIZED_MODE)
        {

        /* perform initialization which has to be done in init mode */
        mpc5200_mscan_perform_init_mode_settings(mscan);
	    }

      if((chan->mode) == MSCAN_SLEEP_MODE)
        {

        /* exit sleep mode */
	    mpc5200_mscan_exit_sleep_mode(mscan);
	    }

      /* exit init mode */
      mpc5200_mscan_exit_init_mode(mscan);
      /* enable ints. */
      mpc5200_mscan_int_enable(mscan);
      /* wait for bus sync. */
      mpc5200_mscan_wait_sync(mscan);
      break;

    case MSCAN_SLEEP_MODE:
      /* disable ints. */
      mpc5200_mscan_int_disable(mscan);
      /* exit sleep mode */
	  mpc5200_mscan_enter_sleep_mode(mscan);
      break;

    default:
      return RTEMS_UNSATISFIED;
      break;

    }

  /* set new channel mode */
  chan->mode = mode;

  return RTEMS_SUCCESSFUL;

  }


/*
 * initialization of channel info.
 */
rtems_status_code mscan_channel_initialize(rtems_device_major_number major, rtems_device_minor_number minor)
  {
  rtems_status_code status;
  struct mscan_channel_info *chan = &chan_info[minor];


  /* set registers according to MSCAN channel information */
  switch(minor)
    {

    case MSCAN_A:
      chan->rx_qname = rtems_build_name ('C', 'N', 'A', 'Q');
      chan->tx_rb_sname = rtems_build_name ('C', 'N', 'A', 'S');

      /* register RTEMS device names for MSCAN A */
      if((status = rtems_io_register_name (MSCAN_A_DEV_NAME, major, MSCAN_A)) != RTEMS_SUCCESSFUL)
	    return status;

      /* register RTEMS device names for MSCAN 0 */
      if((status = rtems_io_register_name (MSCAN_0_DEV_NAME, major, MSCAN_A)) != RTEMS_SUCCESSFUL)
	    return status;

	  /* allocate the space for MSCAN A tx ring buffer */
	  if(((chan->tx_ring_buf.buf_ptr) = malloc(sizeof(struct can_message)*(NO_OF_MSCAN_TX_BUFF+1))) != NULL)
	    {
        chan->tx_ring_buf.head_ptr = chan->tx_ring_buf.tail_ptr = chan->tx_ring_buf.buf_ptr;
	    }
	  else
	    {
		return RTEMS_UNSATISFIED;
	    }
      break;

    case MSCAN_B:
	  chan->rx_qname = rtems_build_name ('C', 'N', 'B', 'Q');
      chan->tx_rb_sname = rtems_build_name ('C', 'N', 'B', 'S');

	  /* register RTEMS device names for MSCAN B */
	  if((status = rtems_io_register_name (MSCAN_B_DEV_NAME, major, MSCAN_B)) != RTEMS_SUCCESSFUL)
	    return status;

      /* register RTEMS device names for MSCAN 1 */
	  if((status = rtems_io_register_name (MSCAN_1_DEV_NAME, major, MSCAN_B)) != RTEMS_SUCCESSFUL)
	    return status;

      /* allocate the space for MSCAN B tx ring buffer */
	  if(((chan->tx_ring_buf.buf_ptr) = malloc(sizeof(struct can_message)*(NO_OF_MSCAN_TX_BUFF+1))) != NULL)
	    {
		chan->tx_ring_buf.head_ptr = chan->tx_ring_buf.tail_ptr = chan->tx_ring_buf.buf_ptr;
	    }
	  else
	    {
		return RTEMS_UNSATISFIED;
	    }
      break;

    default:
      return RTEMS_UNSATISFIED;
      break;
    }

  /* create RTEMS rx message queue */
  status = rtems_message_queue_create(chan->rx_qname,
		                             (uint32_t) NO_OF_MSCAN_RX_BUFF,
		                             (uint32_t) MSCAN_MESSAGE_SIZE(sizeof(struct can_message)),
		                             (rtems_attribute) RTEMS_LOCAL | RTEMS_FIFO,
		                             (rtems_id *)&(chan->rx_qid));

  /* create counting RTEMS tx ring buffer semaphore */
  status = rtems_semaphore_create(chan->tx_rb_sname,
                                 (uint32_t)(NO_OF_MSCAN_TX_BUFF),
                                  RTEMS_COUNTING_SEMAPHORE | RTEMS_NO_INHERIT_PRIORITY | RTEMS_NO_PRIORITY_CEILING | RTEMS_LOCAL,
                                 (rtems_task_priority)0,
                                 (rtems_id *)&(chan->tx_rb_sid));

  /* Set up interrupts */
  if(!BSP_install_rtems_irq_handler(&(mpc5200_mscan_irq_data[minor])))
    rtems_panic("Can't attach MPC5x00 MSCAN interrupt handler %d\n", minor);

  /* basic setup for channel info. struct. */
  chan->regs           = (struct mpc5200_mscan *)&(mpc5200.mscan[minor]);
  chan->int_rx_err     = 0;
  chan->id_extended    = FALSE;
  chan->mode           = MSCAN_INITIALIZED_MODE;
  chan->tx_buf_no      = NO_OF_MSCAN_TX_BUFF;

  return status;

  }


/*
 * MPC5x00 MSCAN device initialization
 */
rtems_device_driver mscan_initialize(rtems_device_major_number major,
                                     rtems_device_minor_number minor,
                                     void *arg
                                    )
  {
  rtems_status_code status;

  /* Initialization requested via RTEMS */
  if((status = mscan_channel_initialize(major,MSCAN_A)) != RTEMS_SUCCESSFUL)
    rtems_fatal_error_occurred(status);

  if((status = mscan_channel_initialize(major,MSCAN_B)) != RTEMS_SUCCESSFUL)
    rtems_fatal_error_occurred(status);

  if((status = mpc5200_mscan_set_mode(MSCAN_A, MSCAN_INIT_NORMAL_MODE)) != RTEMS_SUCCESSFUL)
    rtems_fatal_error_occurred(status);

  if((status = mpc5200_mscan_set_mode(MSCAN_B, MSCAN_INIT_NORMAL_MODE)) != RTEMS_SUCCESSFUL)
    rtems_fatal_error_occurred(status);

  return status;

  }


/*
 * MPC5x00 MSCAN device open
 */
rtems_device_driver mscan_open( rtems_device_major_number major,
                                 rtems_device_minor_number minor,
                                 void * arg
                               )
  {
  rtems_status_code status = RTEMS_SUCCESSFUL;
  struct mscan_channel_info *chan = NULL;

  switch(minor)
    {

    case MSCAN_A:
    case MSCAN_B:
      chan = &chan_info[minor];
      break;

    default:
      return RTEMS_UNSATISFIED;
      break;
    }


  /* check mode */
  if((chan->mode) == MSCAN_SLEEP_MODE)
    {

    /* if not already set enter init mode */
    status = mpc5200_mscan_set_mode(minor, MSCAN_NORMAL_MODE);
    }

  return status;

  }


/*
 * MPC5x00 MSCAN device close
 */
rtems_device_driver mscan_close( rtems_device_major_number major,
                                  rtems_device_minor_number minor,
                                  void * arg
                                )
  {
  rtems_status_code status;
  struct mscan_channel_info *chan = NULL;

  switch(minor)
    {

    case MSCAN_A:
    case MSCAN_B:
	  chan = &chan_info[minor];
      break;

    default:
      return RTEMS_UNSATISFIED;
      break;
    }

  /* enter deep sleep mode */
  status = mpc5200_mscan_set_mode(minor, MSCAN_SLEEP_MODE);

  return status;

  }


/*
 * MPC5x00 MSCAN device read
 */
rtems_device_driver mscan_read( rtems_device_major_number major,
                                 rtems_device_minor_number minor,
                                 void * arg
                               )
  {
  rtems_status_code status;
  uint32_t          message_size = 0;
  rtems_libio_rw_args_t     *parms       = (rtems_libio_rw_args_t *)arg;
  struct mscan_rx_parms     *rx_parms    = (struct mscan_rx_parms *)(parms->buffer);
  struct can_message        *rx_mess     = (struct can_message *)(rx_parms->rx_mess);
  struct mscan_channel_info *chan        = NULL;

  switch(minor)
    {

    case MSCAN_A:
    case MSCAN_B:
	  chan = &chan_info[minor];
      break;

    default:
      return RTEMS_UNSATISFIED;
      break;
    }


  /* end init mode if it is first read */
  if((chan->mode) == MSCAN_INIT_NORMAL_MODE)
    {

    /* if not already set enter init mode */
    mpc5200_mscan_set_mode(minor, MSCAN_NORMAL_MODE);
    }

  if((status = rtems_message_queue_receive(chan->rx_qid,
                                          (void *)(rx_mess),
                                          (uint32_t *)&message_size,
                                          (uint32_t)(rx_parms->rx_flags),
                                          (rtems_interval)(rx_parms->rx_timeout)))
                                          != RTEMS_SUCCESSFUL)
    {

    parms->bytes_moved = 0;

    }
  else
    {

    parms->bytes_moved = sizeof(struct can_message);

    }

  return status;

  }


/*
 * MPC5x00 MSCAN device write
 */
rtems_device_driver mscan_write( rtems_device_major_number major,
                                 rtems_device_minor_number minor,
                                 void * arg
                                )
  {
  rtems_status_code status;
  rtems_libio_rw_args_t         *parms       = (rtems_libio_rw_args_t *)arg;
  struct mscan_tx_parms         *tx_parms    = (struct mscan_tx_parms *)(parms->buffer);
  struct can_message            *tx_mess     = (struct can_message *)(tx_parms->tx_mess);
  struct mscan_channel_info     *chan        = NULL;
  mscan_handle                  *mscan_hdl   = NULL;
  volatile struct mpc5200_mscan *mscan       = NULL;

  switch(minor)
    {
    case MSCAN_A:
    case MSCAN_B:
	  chan      = &chan_info[minor];
      mscan_hdl = mpc5200_mscan_irq_data[minor].handle;
      mscan     = chan->regs;
      break;

    default:
      return RTEMS_UNSATISFIED;
      break;
    }

  /* end init mode if it is first write */
  if((chan->mode) == MSCAN_INIT_NORMAL_MODE)
    {

    /* if not already set enter init mode */
    mpc5200_mscan_set_mode(minor, MSCAN_NORMAL_MODE);
    }

  /* preset moved bytes */
  parms->bytes_moved = 0;

  /* obtain counting semaphore of tx ring buffer */
  if((status = rtems_semaphore_obtain((rtems_id)(chan->tx_rb_sid),
                                       RTEMS_NO_WAIT,
	                                  (rtems_interval)0))
	                                == RTEMS_SUCCESSFUL)
    {

    /* append the TOUCAN tx_id to the mess. due to interrupt handling */
	tx_mess->toucan_tx_id = tx_parms->tx_id;

    /* fill the tx ring buffer with the message */
    fill_tx_buffer(chan, tx_mess);

    /* enable message buffer specific interrupt */
    mscan->tier |= (TIER_TXEI0 | TIER_TXEI1 | TIER_TXEI2);

    /* calculate moved bytes */
    parms->bytes_moved = (tx_mess->mess_len) & 0x000F;

    }

  return status;

  }


/*
 * MPC5x00 MSCAN device control
 */
rtems_device_driver mscan_control( rtems_device_major_number major,
                                    rtems_device_minor_number minor,
                                    void * arg
                                  )
  {
  rtems_status_code status;
  uint16_t tx_id;
  rtems_libio_ioctl_args_t      *parms       = (rtems_libio_ioctl_args_t *)arg;
  struct mscan_ctrl_parms       *ctrl_parms  = (struct mscan_ctrl_parms *)(parms->buffer);
  struct mscan_channel_info     *chan        = NULL;
  mscan_handle                  *mscan_hdl   = NULL;
  volatile struct mpc5200_mscan *mscan       = NULL;
  uint8_t                       tx_buf_count = 0;

  switch(minor)
    {

    case MSCAN_A:
    case MSCAN_B:
	  chan = &chan_info[minor];
      mscan_hdl  = mpc5200_mscan_irq_data[minor].handle;
      mscan = chan->regs;
      break;

    default:
      return RTEMS_UNSATISFIED;
      break;
    }

  switch(parms->command)
    {

      /* TOUCAN callback initialization for MSCAN */
    case TOUCAN_MSCAN_INIT:
      mscan_hdl->toucan_callback = ctrl_parms->toucan_cb_fnc;
      break;

    /* set rx buffer ID */
    case MSCAN_SET_RX_ID:

      /* enter init mode */
      mpc5200_mscan_enter_init_mode(mscan);

      switch(ctrl_parms->ctrl_reg_no)
        {

        case RX_BUFFER_0:
          mscan->idar0  = SET_IDR0(ctrl_parms->ctrl_id);
          mscan->idar1  = SET_IDR1(ctrl_parms->ctrl_id);
          break;

        case RX_BUFFER_1:
          mscan->idar2  = SET_IDR2(ctrl_parms->ctrl_id);
          mscan->idar3  = SET_IDR3(ctrl_parms->ctrl_id);
          break;

        case RX_BUFFER_2:
          mscan->idar4  = SET_IDR4(ctrl_parms->ctrl_id);
          mscan->idar5  = SET_IDR5(ctrl_parms->ctrl_id);
          break;

        case RX_BUFFER_3:
          mscan->idar6  = SET_IDR6(ctrl_parms->ctrl_id);
          mscan->idar7  = SET_IDR7(ctrl_parms->ctrl_id);
          break;

        default:
        break;

        }

      /* exit init mode and perform further initialization which is required in the normal mode */
      mpc5200_mscan_exit_init_mode(mscan);

      /* enable ints. */
      mpc5200_mscan_int_enable(mscan);

      /* wait for bus sync. */
      mpc5200_mscan_wait_sync(mscan);

      return RTEMS_SUCCESSFUL;
      break;

    /* get rx buffer ID */
    case MSCAN_GET_RX_ID:

      switch(ctrl_parms->ctrl_reg_no)
	    {

        case RX_BUFFER_0:
          ctrl_parms->ctrl_id = GET_IDR0(mscan->idar0) | GET_IDR1(mscan->idar1);
          break;

        case RX_BUFFER_1:
          ctrl_parms->ctrl_id = GET_IDR2(mscan->idar2) | GET_IDR3(mscan->idar3);
          break;

        case RX_BUFFER_2:
          ctrl_parms->ctrl_id = GET_IDR4(mscan->idar4) | GET_IDR5(mscan->idar5);
          break;

        case RX_BUFFER_3:
          ctrl_parms->ctrl_id = GET_IDR6(mscan->idar6) | GET_IDR7(mscan->idar7);
          break;

        default:
        break;

        }

      break;

    /* set rx buffer ID mask */
    case MSCAN_SET_RX_ID_MASK:

      /* enter init mode */
      mpc5200_mscan_enter_init_mode(mscan);

      switch(ctrl_parms->ctrl_reg_no)
        {

        case RX_BUFFER_0:
          mscan->idmr0  = SET_IDMR0(ctrl_parms->ctrl_id_mask);
          mscan->idmr1  = SET_IDMR1(ctrl_parms->ctrl_id_mask);
          break;

        case RX_BUFFER_1:
          mscan->idmr2  = SET_IDMR2(ctrl_parms->ctrl_id_mask);
          mscan->idmr3  = SET_IDMR3(ctrl_parms->ctrl_id_mask);
          break;

        case RX_BUFFER_2:
          mscan->idmr4  = SET_IDMR4(ctrl_parms->ctrl_id_mask);
          mscan->idmr5  = SET_IDMR5(ctrl_parms->ctrl_id_mask);
          break;

        case RX_BUFFER_3:
          mscan->idmr6  = SET_IDMR6(ctrl_parms->ctrl_id_mask);
          mscan->idmr7  = SET_IDMR7(ctrl_parms->ctrl_id_mask);
          break;

        default:
        break;

        }

      /* exit init mode and perform further initialization which is required in the normal mode */
      mpc5200_mscan_exit_init_mode(mscan);

      /* enable ints. */
      mpc5200_mscan_int_enable(mscan);

      /* wait for bus sync. */
      mpc5200_mscan_wait_sync(mscan);

      break;

    /* get rx buffer ID mask */
    case MSCAN_GET_RX_ID_MASK:

      switch(ctrl_parms->ctrl_reg_no)
        {

        case RX_BUFFER_0:
          ctrl_parms->ctrl_id_mask = GET_IDMR0(mscan->idmr0) | GET_IDMR1(mscan->idmr1);
          break;

        case RX_BUFFER_1:
          ctrl_parms->ctrl_id_mask = GET_IDMR2(mscan->idmr2) | GET_IDMR3(mscan->idmr3);
          break;

        case RX_BUFFER_2:
          ctrl_parms->ctrl_id_mask = GET_IDMR4(mscan->idmr4) | GET_IDMR5(mscan->idmr5);
          break;

        case RX_BUFFER_3:
          ctrl_parms->ctrl_id_mask = GET_IDMR6(mscan->idmr6) | GET_IDMR7(mscan->idmr7);
          break;

        default:
        break;

        }

    /* set tx buffer ID */
    case MSCAN_SET_TX_ID:

      /* check for availability of tx buffer */
      if(!((mscan->tflg) & (uint8_t)(ctrl_parms->ctrl_reg_no)))
        {

        /* do abort tx buf. request */
        mscan->tarq = (uint8_t)(ctrl_parms->ctrl_reg_no);

        /* wait for abort tx buf. ack. */
        while((mscan->taak) & (uint8_t)(ctrl_parms->ctrl_reg_no));

        }

      /* select tx buf. */
      mscan->bsel   = (uint8_t)(ctrl_parms->ctrl_reg_no);

      /* set the tx id of selected buf. */
      tx_id = ctrl_parms->ctrl_id;
      mscan->txidr0 = SET_IDR0(tx_id);
      mscan->txidr1 = SET_IDR1(tx_id);
      mscan->txidr2 = 0;
      mscan->txidr3 = 0;

      break;

    /* get tx buffer ID */
    case MSCAN_GET_TX_ID:

      /* select tx buf. */
      mscan->bsel   = (uint8_t)(ctrl_parms->ctrl_reg_no);

      /* get tx id. of selected buf. */
      ctrl_parms->ctrl_id = GET_IDR0(mscan->txidr0) | GET_IDR1(mscan->txidr1);

      break;

    /* set can bitrate */
    case MSCAN_SET_BAUDRATE:

      /* check bitrate settings */
      if(((ctrl_parms->ctrl_can_bitrate) >= CAN_BIT_RATE_MIN) && ((ctrl_parms->ctrl_can_bitrate) <= CAN_BIT_RATE_MAX)) {

        /* enter init mode */
        mpc5200_mscan_enter_init_mode(mscan);

        /* perform all can bit time settings */
        mpc5200_mscan_perform_bit_time_settings(mscan,(uint32_t)(ctrl_parms->ctrl_can_bitrate),IPB_CLOCK);

        /* exit init mode and perform further initialization which is required in the normal mode */
        mpc5200_mscan_exit_init_mode(mscan);

        /* enable ints. */
        mpc5200_mscan_int_enable(mscan);

        /* wait for bus sync. */
        mpc5200_mscan_wait_sync(mscan);

	    return RTEMS_SUCCESSFUL;
	    }
	  else {

	     return RTEMS_UNSATISFIED;
	     }

      break;

    case SET_TX_BUF_NO:

      /* check for different settings of tx ring buffer */
      if((tx_buf_count = chan->tx_buf_no) != (uint8_t)(ctrl_parms->ctrl_tx_buf_no))
        {

        /* preset the channel specific no of messages in the tx ring buffer */
        tx_buf_count = chan->tx_buf_no;

        /* try to obtain all of the tx ring buffers */
        while(tx_buf_count > 0)
          {

          /* obtain semaphore of all tx ring buffers */
		  if((status = rtems_semaphore_obtain((rtems_id)(chan->tx_rb_sid),
		  	                                   RTEMS_WAIT,
		  	                                  (rtems_interval)10))
	                                        == RTEMS_SUCCESSFUL)
	        {

		    tx_buf_count--;

	        }

          }

        /* free the former tx ring buffer */
        free((void *)chan->tx_ring_buf.buf_ptr);

        /* allocate the tx ring buffer with new size */
	    if(((chan->tx_ring_buf.buf_ptr) = malloc(sizeof(struct can_message)*((uint8_t)(ctrl_parms->ctrl_tx_buf_no)+1))) != NULL)
	      {
		  chan->tx_ring_buf.head_ptr = chan->tx_ring_buf.tail_ptr = chan->tx_ring_buf.buf_ptr;
	      }
	    else
	      {
		  return RTEMS_UNSATISFIED;
	      }

        /* set the new amount of tx buffers */
        chan->tx_buf_no =  (uint8_t)(ctrl_parms->ctrl_tx_buf_no);

        /* release the semaphore of all tx ring buffers */
        while(tx_buf_count < chan->tx_buf_no)
		  {

		  /* obtain semaphore of all tx ring buffers */
	      rtems_semaphore_release((rtems_id)(chan->tx_rb_sid));

		  tx_buf_count++;

		  }

	    }
	  else
	    {

        return RTEMS_SUCCESSFUL;

	    }
      break;

    default:
      break;

    }

  return RTEMS_SUCCESSFUL;

  }