/******************** (C) COPYRIGHT 2003 STMicroelectronics ********************
* File Name          : can.c
* Author             : MCD Application Team
* Date First Issued  : 10/27/2003
* Description        : This file contains all the functions prototypes for the
*                      CAN bus software library.
********************************************************************************
* History:
*  13/01/2006 : V3.1
*  24/05/2005 : V3.0
*  30/11/2004 : V2.0
*  14/07/2004 : V1.3
*  01/01/2004 : V1.2
*******************************************************************************
 THE PRESENT SOFTWARE WHICH IS FOR GUIDANCE ONLY AIMS AT PROVIDING CUSTOMERS WITH
 CODING INFORMATION REGARDING THEIR PRODUCTS IN ORDER FOR THEM TO SAVE TIME.
 AS A RESULT, STMICROELECTRONICS SHALL NOT BE HELD LIABLE FOR ANY DIRECT, INDIRECT
 OR CONSEQUENTIAL DAMAGES WITH RESPECT TO ANY CLAIMS ARISING FROM THE CONTENT
 OF SUCH SOFTWARE AND/OR THE USE MADE BY CUSTOMERS OF THE CODING INFORMATION
 CONTAINED HEREIN IN CONNECTION WITH THEIR PRODUCTS.
*******************************************************************************/

#include "can.h"
#include "xti.h"
#include "pcu.h"

// macro to format the timing register value from the timing parameters
#define CAN_TIMING(tseg1, tseg2, sjw, brp)	(((tseg2-1) & 0x07) << 12) | (((tseg1-1) & 0x0F) << 8) | (((sjw-1) & 0x03) << 6) | ((brp-1) & 0x3F)

// array of pre-defined timing parameters for standard bitrates
u16 CanTimings[] = {         /* value   bitrate     NTQ  TSEG1  TSEG2  SJW  BRP */
	CAN_TIMING(11, 4, 4, 5), /* 0x3AC4  100 kbit/s  16   11     4      4    5   */
	CAN_TIMING(11, 4, 4, 4), /* 0x3AC3  125 kbit/s  16   11     4      4    4   */
	CAN_TIMING( 4, 3, 3, 4), /* 0x2383  250 kbit/s   8    4     3      3    4   */
	CAN_TIMING(13, 2, 1, 1), /* 0x1C00  500 kbit/s  16   13     2      1    1   */
	CAN_TIMING( 4, 3, 1, 1), /* 0x2300  1 Mbit/s     8    4     3      1    1   */
};

/*******************************************************************************
* Function Name  : CAN_SetBitrate
* Description    : Setup a standard CAN bitrate
* Input 1        : one of the CAN_BITRATE_xxx defines
* Output         : None
* Return         : None
* Note           : CAN must be in initialization mode
*******************************************************************************/
void CAN_SetBitrate(u32 bitrate)
{
  /* write the predefined timing value */
  CAN->BTR = CanTimings[bitrate];

  /* clear the Extended Baud Rate Prescaler */
  CAN->BRPR = 0; 		
}

/*******************************************************************************
* Function Name  : CAN_SetTiming
* Description    : Setup the CAN timing with specific parameters
* Input 1        : Time Segment before the sample point position, from 2 to 16
* Input 2        : Time Segment after the sample point position, from 1 to 8
* Input 3        : Synchronisation Jump Width, from 1 to 4
* Input 4        : Baud Rate Prescaler, from 1 to 1024
* Output         : None
* Return         : None
* Note           : CAN must be in initialization mode
*******************************************************************************/
void CAN_SetTiming(u32 tseg1, u32 tseg2, u32 sjw, u32 brp)
{
	CAN->BTR = CAN_TIMING(tseg1, tseg2, sjw, brp);
	CAN->BRPR = ((brp-1) >> 6) & 0x0F;
}

/*******************************************************************************
* Function Name  : CAN_SleepRequest
* Description    : Request the CAN cell to enter sleep mode
* Input 1        : CAN_WAKEUP_ON_EXT or CAN_WAKEUP_ON_CAN
* Output         : None
* Return         : None
*******************************************************************************/
void CAN_SleepRequest(u32 WakeupMode)
{
	/* Wakeup Line 6 is linked to CAN RX pin (port 1.11) */
	/* Wakeup Line 2 is linked to external pin (port 2.8) */
	u32 WakeupLine = (WakeupMode == CAN_WAKEUP_ON_CAN ? XTI_Line6 : XTI_Line2);

	CAN_WaitEndOfTx();

	XTI_Init();

	/* Configure the Wakeup Line mode, select Falling edge (transition to dominant state) */
	XTI_LineModeConfig(WakeupLine, XTI_FallingEdge);

	/* Enable Wake-Up interrupt */
	XTI_LineConfig(WakeupLine, ENABLE);

	/* Enable Wake-Up mode with interrupt */
	XTI_ModeConfig(XTI_WakeUpInterrupt, ENABLE);

	XTI_PendingBitClear(XTI_InterruptLineValue());

	/* Enter STOP mode (resume execution from here) */
	PCU_LPMEnter(PCU_STOP);
}

/*******************************************************************************
* Function Name  : CAN_GetFreeIF
* Description    : Search the first free message interface, starting from 0
* Input          : None
* Output         : None
* Return         : A free message interface number (0 or 1) if found, else 2
*******************************************************************************/
static u32 CAN_GetFreeIF(void)
{
	if ((CAN->sMsgObj[0].CRR & CAN_CRR_BUSY) == 0)
		return 0;
	else if ((CAN->sMsgObj[1].CRR & CAN_CRR_BUSY) == 0)
		return 1;
	else return 2;
}

/*******************************************************************************
* Macro Name     : xxx_ID_MSK, xxx_ID_ARB
* Description    : Form the Mask and Arbitration registers value to filter a 
*                  range of identifiers or a fixed identifier, for standard 
*                  and extended IDs
*******************************************************************************/
#define RANGE_ID_MSK(range_start, range_end)	(~((range_end) - (range_start)))
#define RANGE_ID_ARB(range_start, range_end)	((range_start) & (range_end))

#define FIXED_ID_MSK(id)	RANGE_ID_MSK((id), (id))
#define FIXED_ID_ARB(id)	RANGE_ID_ARB((id), (id))

#define STD_RANGE_ID_MSK(range_start, range_end)	((u16)((RANGE_ID_MSK((range_start), (range_end)) & 0x7FF) << 2))
#define STD_RANGE_ID_ARB(range_start, range_end)	((u16)(RANGE_ID_ARB((range_start), (range_end)) << 2))

#define STD_FIXED_ID_MSK(id)	((u16)((FIXED_ID_MSK(id) & 0x7FF) << 2))
#define STD_FIXED_ID_ARB(id)	((u16)(FIXED_ID_ARB(id) << 2))

#define EXT_RANGE_ID_MSK_L(range_start, range_end)	((u16)(RANGE_ID_MSK((range_start), (range_end)) >> 11))
#define EXT_RANGE_ID_MSK_H(range_start, range_end)	((u16)(STD_RANGE_ID_MSK((range_start), (range_end)) | ((RANGE_ID_MSK((range_start), (range_end)) >> 27) & 0x03)))
#define EXT_RANGE_ID_ARB_L(range_start, range_end)	((u16)(RANGE_ID_ARB((range_start), (range_end)) >> 11))
#define EXT_RANGE_ID_ARB_H(range_start, range_end)	((u16)(STD_RANGE_ID_ARB((range_start), (range_end)) | ((RANGE_ID_ARB((range_start), (range_end)) >> 27) & 0x03)))

#define EXT_FIXED_ID_MSK_L(id)	((u16)(FIXED_ID_MSK(id) >> 11))
#define EXT_FIXED_ID_MSK_H(id)	((u16)(STD_FIXED_ID_MSK(id) | ((FIXED_ID_MSK(id) >> 27) & 0x03)))
#define EXT_FIXED_ID_ARB_L(id)	((u16)(FIXED_ID_ARB(id) >> 11))
#define EXT_FIXED_ID_ARB_H(id)	((u16)(STD_FIXED_ID_ARB(id) | ((FIXED_ID_ARB(id) >> 27) & 0x03)))

/*******************************************************************************
* Function Name  : CAN_SetUnusedMsgObj
* Description    : Configure the message object as unused
* Input 1        : message object number, from 0 to 31
* Output         : None
* Return         : None
*******************************************************************************/
void CAN_SetUnusedMsgObj(u32 msgobj)
{
	u32 msg_if;
    while ((msg_if = CAN_GetFreeIF()) == 2);

  	CAN->sMsgObj[msg_if].CMR =  CAN_CMR_WRRD
  	                          | CAN_CMR_MASK
  	                          | CAN_CMR_ARB
  	                          | CAN_CMR_CONTROL
  	                          | CAN_CMR_DATAA
  	                          | CAN_CMR_DATAB;

  	CAN->sMsgObj[msg_if].M1R = 0;
  	CAN->sMsgObj[msg_if].M2R = 0;

  	CAN->sMsgObj[msg_if].A1R = 0;
  	CAN->sMsgObj[msg_if].A2R = 0;

  	CAN->sMsgObj[msg_if].MCR = 0;

  	CAN->sMsgObj[msg_if].DA1R = 0;
  	CAN->sMsgObj[msg_if].DA2R = 0;
  	CAN->sMsgObj[msg_if].DB1R = 0;
  	CAN->sMsgObj[msg_if].DB2R = 0;

  	CAN->sMsgObj[msg_if].CRR = 1 + msgobj;
}

/*******************************************************************************
* Function Name  : CAN_SetTxMsgObj
* Description    : Configure the message object as TX
* Input 1        : message object number, from 0 to 31
* Input 2        : CAN_STD_ID or CAN_EXT_ID
* Output         : None
* Return         : None
*******************************************************************************/
void CAN_SetTxMsgObj(u32 msgobj, u32 idType)
{
	u32 msg_if;
    while ((msg_if = CAN_GetFreeIF()) == 2);

  	CAN->sMsgObj[msg_if].CMR =  CAN_CMR_WRRD
  	                          | CAN_CMR_MASK
  	                          | CAN_CMR_ARB
  	                          | CAN_CMR_CONTROL
  	                          | CAN_CMR_DATAA
  	                          | CAN_CMR_DATAB;

	CAN->sMsgObj[msg_if].M1R = 0;
	CAN->sMsgObj[msg_if].A1R = 0;

	if (idType == CAN_STD_ID)
	{
  		CAN->sMsgObj[msg_if].M2R = CAN_M2R_MDIR;
  		CAN->sMsgObj[msg_if].A2R = CAN_A2R_MSGVAL | CAN_A2R_DIR;
  	}
  	else
  	{
  		CAN->sMsgObj[msg_if].M2R = CAN_M2R_MDIR | CAN_M2R_MXTD;
  		CAN->sMsgObj[msg_if].A2R = CAN_A2R_MSGVAL | CAN_A2R_DIR | CAN_A2R_XTD;
  	}

  	CAN->sMsgObj[msg_if].MCR = CAN_MCR_TXIE | CAN_MCR_EOB;

  	CAN->sMsgObj[msg_if].DA1R = 0;
  	CAN->sMsgObj[msg_if].DA2R = 0;
  	CAN->sMsgObj[msg_if].DB1R = 0;
  	CAN->sMsgObj[msg_if].DB2R = 0;

  	CAN->sMsgObj[msg_if].CRR = 1 + msgobj;
}

/*******************************************************************************
* Function Name  : CAN_SetRxMsgObj
* Description    : Configure the message object as RX
* Input 1        : message object number, from 0 to 31
* Input 2        : CAN_STD_ID or CAN_EXT_ID
* Input 3        : low part of the identifier range used for acceptance filtering
* Input 4        : high part of the identifier range used for acceptance filtering
* Input 5        : TRUE for a single receive object or a FIFO receive object that
*                  is the last one of the FIFO
*                  FALSE for a FIFO receive object that is not the last one
* Output         : None
* Return         : None
*******************************************************************************/
void CAN_SetRxMsgObj(u32 msgobj, u32 idType, u32 idLow, u32 idHigh, bool singleOrFifoLast)
{
	u32 msg_if;
    while ((msg_if = CAN_GetFreeIF()) == 2);

  	CAN->sMsgObj[msg_if].CMR =  CAN_CMR_WRRD
  	                          | CAN_CMR_MASK
  	                          | CAN_CMR_ARB
  	                          | CAN_CMR_CONTROL
  	                          | CAN_CMR_DATAA
  	                          | CAN_CMR_DATAB;

	if (idType == CAN_STD_ID)
	{
  		CAN->sMsgObj[msg_if].M1R = 0;
  		CAN->sMsgObj[msg_if].M2R = STD_RANGE_ID_MSK(idLow, idHigh);

  		CAN->sMsgObj[msg_if].A1R = 0;
  		CAN->sMsgObj[msg_if].A2R = CAN_A2R_MSGVAL | STD_RANGE_ID_ARB(idLow, idHigh);
  	}
  	else
  	{
  		CAN->sMsgObj[msg_if].M1R = EXT_RANGE_ID_MSK_L(idLow, idHigh);
  		CAN->sMsgObj[msg_if].M2R = CAN_M2R_MXTD | EXT_RANGE_ID_MSK_H(idLow, idHigh);

  		CAN->sMsgObj[msg_if].A1R = EXT_RANGE_ID_ARB_L(idLow, idHigh);
  		CAN->sMsgObj[msg_if].A2R = CAN_A2R_MSGVAL | CAN_A2R_XTD | EXT_RANGE_ID_ARB_H(idLow, idHigh);
  	}

  	CAN->sMsgObj[msg_if].MCR = CAN_MCR_RXIE | CAN_MCR_UMASK | (singleOrFifoLast ? CAN_MCR_EOB : 0);

  	CAN->sMsgObj[msg_if].DA1R = 0;
  	CAN->sMsgObj[msg_if].DA2R = 0;
  	CAN->sMsgObj[msg_if].DB1R = 0;