s3c44b0-mcp2510.c

S3C2410处理器上的Linux 2.4内核CAN总线驱动程序

*		CanData为CAN数据结构							*
\***********************************************************/
static void MCP2510_Read_Can(unsigned char nbuffer, PCanData candata)
{

	unsigned char mcp_addr = (nbuffer<<4) + 0x31, ctrl;
	int IsExt;
	char dlc;

	IsExt=MCP2510_Read_Can_ID( mcp_addr, &(candata->id));

	ctrl=MCP2510_Read(mcp_addr-1);
	dlc=MCP2510_Read( mcp_addr+4);
	if ((ctrl & 0x08)) {
		candata->rxRTR = TRUE;
	}
	else{
		candata->rxRTR = FALSE;
	}
	dlc &= DLC_MASK;
	MCP2510_SRead(mcp_addr+5, candata->data, dlc);

	candata->dlc=dlc;
}
/*******************************************\
*	设置MCP2510 CAN总线ID				*
*	参数: address为MCP2510寄存器地址*
*			can_id为设置的ID值			*
*			IsExt表示是否为扩展ID	*
\*******************************************/
static void MCP2510_Write_Can_ID(int address, __u32 can_id, int IsExt)
{
	__u32 tbufdata;

	if (IsExt) {
		can_id&=0x1fffffff;	//29位
		tbufdata=can_id &0xffff;
		tbufdata<<=16;
		tbufdata|=((can_id>>(18-5))&(~0x1f));
		tbufdata |= TXB_EXIDE_M;
	}
	else{
		can_id&=0x7ff;	//11位
		tbufdata= (can_id>>3)|((can_id&0x7)<<13);
	}
	MCP2510_Swrite(address, (unsigned char*)&tbufdata, 4);
	MCP2510_Read_Can_ID(address, &tbufdata);
	DPRINTK("write can id=%x, result id=%x\n",can_id, tbufdata);
}

/***********************************************************\
*	写入MCP2510 发送的数据							*
*	参数: 													*
*		nbuffer为第几个缓冲区可以为0、1、2		*
*		CanData为CAN数据结构							*
\***********************************************************/
static void MCP2510_Write_Can( unsigned char nbuffer, PCanData candata)
{
	unsigned char dlc;
	unsigned char mcp_addr = (nbuffer<<4) + 0x31;

	dlc=candata->dlc;
	MCP2510_Swrite(mcp_addr+5, candata->data, dlc);  // write data bytes
	MCP2510_Write_Can_ID( mcp_addr, candata->id,candata->IsExt);  // write CAN id
	if (candata->rxRTR)
		dlc |= RTR_MASK;  // if RTR set bit in byte
	MCP2510_Write((mcp_addr+4), dlc);            // write the RTR and DLC
}

/***********************************************************\
*	write and send Can data									*
*	we must set can id first.										*
*	parament:												*
*		nbuffer: which buffer, should be: 0, 1, 2					*
*		pbuffer: send data 										*
*		nbuffer: size of data 									*
\***********************************************************/
static void MCP2510_Write_CanData( unsigned char nbuffer, char *pbuffer, int nsize)
{
	unsigned char dlc;
	unsigned char mcp_addr = (nbuffer<<4) + 0x31;

	dlc=nsize&DLC_MASK;	//nbuffer must <= 8
	MCP2510_Swrite(mcp_addr+5, pbuffer, dlc);  // write data bytes
	MCP2510_Write((mcp_addr+4), dlc);            // write the RTR and DLC
}

/***********************************************************\
*	write and send Remote Can Frame							*
*	we must set can id first.										*
*	parament:												*
*		nbuffer: which buffer, should be: 0, 1, 2					*
\***********************************************************/
static void MCP2510_Write_CanRTR( unsigned char nbuffer)
{
	unsigned char dlc=0;
	unsigned char mcp_addr = (nbuffer<<4) + 0x31;

	dlc |= RTR_MASK;  // if RTR set bit in byte
	MCP2510_Write((mcp_addr+4), dlc);            // write the RTR and DLC
}


// Setup the CAN buffers used by the application.
// We currently use only one for reception and one for transmission.
// It is possible to use several to get a simple form of queue.
//
// We setup the unit to receive all CAN messages.
// As we only have at most 4 different messages to receive, we could use the
// filters to select them for us.
//
// mcp_init() should already have been called.
static void MCP2510_Setup(PCanFilter pfilter)
{
    // As no filters are active, all messages will be stored in RXB0 only if
    // no roll-over is active. We want to recieve all CAN messages (standard and extended)
    // (RXM<1:0> = 11).
    //SPI_mcp_write_bits(RXB0CTRL, RXB_RX_ANY, 0xFF);
    //SPI_mcp_write_bits(RXB1CTRL, RXB_RX_ANY, 0xFF);

    // But there is a bug in the chip, so we have to activate roll-over.
	if(pfilter){	//有过滤器
		MCP2510_WriteBits(RXB0CTRL, (RXB_BUKT|RXB_RX_STDEXT|RXB_RXRTR|RXB_RXF0), 0xFF);
		MCP2510_WriteBits(RXB1CTRL, RXB_RX_STDEXT, 0xFF);
	}
	else{
		MCP2510_WriteBits(RXB0CTRL, (RXB_BUKT|RXB_RX_ANY|RXB_RXRTR), 0xFF);
		MCP2510_WriteBits(RXB1CTRL, RXB_RX_ANY, 0xFF);
	}
}

/***********************************************************************************\
								发送数据
	参数:
		data，发送数据

	Note: 使用三个缓冲区循环发送，没有做缓冲区有效检测
\***********************************************************************************/
static int ntxbuffer=0;

static inline void MCP2510_canTxBuffer(void)
{
	switch(ntxbuffer){
	case 0:
		MCP2510_transmit(TXB0CTRL);
		ntxbuffer=1;
		break;
	case 1:
		MCP2510_transmit(TXB1CTRL);
		ntxbuffer=2;
		break;
	case 2:
		MCP2510_transmit(TXB2CTRL);
		ntxbuffer=0;
		break;
	}
}

static inline void MCP2510_canWrite(PCanData data)
{
	MCP2510_Write_Can(ntxbuffer, data);
	MCP2510_canTxBuffer();
}

static inline void MCP2510_canWriteData(char *pbuffer, int nbuffer)
{
	MCP2510_Write_CanData(ntxbuffer, pbuffer, nbuffer);
	MCP2510_canTxBuffer();
}

static inline void MCP2510_canWriteRTR(void)
{
	MCP2510_Write_CanRTR(ntxbuffer);
	MCP2510_canTxBuffer();
}


/***********************************************************************************\
								中断服务程序									
\***********************************************************************************/

static void s3c44b0_isr_mcp2510(void)
{
	unsigned char byte;

	DPRINTK("enter interrupt!\n");

	byte=MCP2510_Read(CANINTF);

	if(byte & RX0INT){
		MCP2510_Read_Can(3,&(mcp2510dev.MCP2510_Candata[mcp2510dev.nCanRevpos]));
		MCP2510_WriteBits(CANINTF, ~RX0INT, RX0INT); // Clear interrupt
		NextCanDataPos(mcp2510dev.nCanRevpos);
	}

	if(byte & RX1INT){
		MCP2510_Read_Can(4,&(mcp2510dev.MCP2510_Candata[mcp2510dev.nCanRevpos]));
		MCP2510_WriteBits(CANINTF, ~RX1INT, RX1INT); // Clear interrupt
		NextCanDataPos(mcp2510dev.nCanRevpos);
	}

	if(byte & (RX0INT|RX1INT)){
		wake_up_interruptible(&(mcp2510dev.wq));
	}
}

/*********************************************************************\
	CAN设备初始化函数
	参数:	bandrate，CAN波特率
\*********************************************************************/
static int init_MCP2510(CanBandRate bandrate)
{
	unsigned char i,j,a;
	MCP2510_Reset();

	MCP2510_SetBandRate(bandrate,FALSE);

	// Disable interrups.
	MCP2510_Write(CANINTE, NO_IE);

	// Mark all filter bits as don't care:
	MCP2510_Write_Can_ID(RXM0SIDH, 0, TRUE);
	MCP2510_Write_Can_ID(RXM1SIDH, 0, TRUE);
	// Anyway, set all filters to 0:
	MCP2510_Write_Can_ID(RXF0SIDH, 0, 0);
	MCP2510_Write_Can_ID(RXF1SIDH, 0, 0);
	MCP2510_Write_Can_ID(RXF2SIDH, 0, 0);
	MCP2510_Write_Can_ID(RXF3SIDH, 0, 0);
	MCP2510_Write_Can_ID(RXF4SIDH, 0, 0);
	MCP2510_Write_Can_ID(RXF5SIDH, 0, 0);

	//Enable clock output
	MCP2510_Write(CLKCTRL, MODE_LOOPBACK| CLKEN | CLK1);

	// Clear, deactivate the three transmit buffers
	a = TXB0CTRL;
	for (i = 0; i < 3; i++) {
		for (j = 0; j < 14; j++) {
			MCP2510_Write(a, 0);
			a++;
	        }
       	a += 2; // We did not clear CANSTAT or CANCTRL
	}
	// and the two receive buffers.
	MCP2510_Write(RXB0CTRL, 0);
	MCP2510_Write(RXB1CTRL, 0);

	// The two pins RX0BF and RX1BF are used to control two LEDs; set them as outputs and set them as 00.
	MCP2510_Write(BFPCTRL, 0x3C);
	
	return 0;
}

static void MCP2510_SetFilter(PCanFilter pfilter)
{
	MCP2510_Write(MCP2510REG_CANCTRL, MODE_CONFIG);
	// Disable interrups.
	MCP2510_Write(CANINTE, NO_IE);

	if(!pfilter){
		// Mark all filter bits as don't care:
		MCP2510_Write_Can_ID(RXM0SIDH, 0, TRUE);
		MCP2510_Write_Can_ID(RXM1SIDH, 0, TRUE);
		// Anyway, set all filters to 0:
		MCP2510_Write_Can_ID(RXF0SIDH, 0, 0);
		MCP2510_Write_Can_ID(RXF1SIDH, 0, 0);
		MCP2510_Write_Can_ID(RXF2SIDH, 0, 0);
		MCP2510_Write_Can_ID(RXF3SIDH, 0, 0);
		MCP2510_Write_Can_ID(RXF4SIDH, 0, 0);
		MCP2510_Write_Can_ID(RXF5SIDH, 0, 0);
	}
	else{
		// Mark
		MCP2510_Write_Can_ID(RXM0SIDH, pfilter->Mask, TRUE);
		MCP2510_Write_Can_ID(RXM1SIDH, pfilter->Mask, TRUE);

		// set all filters to same = pfilter->Filter:
		MCP2510_Write_Can_ID(RXF0SIDH, pfilter->Filter, pfilter->IsExt);
		MCP2510_Write_Can_ID(RXF1SIDH, pfilter->Filter, pfilter->IsExt);
		MCP2510_Write_Can_ID(RXF2SIDH, pfilter->Filter, pfilter->IsExt);
		MCP2510_Write_Can_ID(RXF3SIDH, pfilter->Filter, pfilter->IsExt);
		MCP2510_Write_Can_ID(RXF4SIDH, pfilter->Filter, pfilter->IsExt);
		MCP2510_Write_Can_ID(RXF5SIDH, pfilter->Filter, pfilter->IsExt);
	}
	//Enable clock output
	if(mcp2510dev.loopbackmode)
		MCP2510_Write(CLKCTRL, MODE_LOOPBACK| CLKEN | CLK1);
	else
		MCP2510_Write(CLKCTRL, MODE_NORMAL| CLKEN | CLK1);

	// and the two receive buffers.
	MCP2510_Write(RXB0CTRL, 0);
	MCP2510_Write(RXB1CTRL, 0);

	MCP2510_Setup(pfilter);
}

static int s3c44b0_mcp2510_ioctl(struct inode *inode, struct file *file, 
                                unsigned int cmd, unsigned long arg)
{
	int flags;

	local_irq_save(flags);
	switch (cmd){
	case UPCAN_IOCTRL_SETBAND:	//set can bus band rate
		MCP2510_SetBandRate((CanBandRate)arg ,TRUE);
		mdelay(10);
		break;
	case UPCAN_IOCTRL_SETID:	//set can frame id data
		MCP2510_Write_Can_ID(TXB0SIDH, arg, arg&UPCAN_EXCAN);
		MCP2510_Write_Can_ID(TXB1SIDH, arg, arg&UPCAN_EXCAN);
		MCP2510_Write_Can_ID(TXB2SIDH, arg, arg&UPCAN_EXCAN);
		break;
	case UPCAN_IOCTRL_SETLPBK:	//set can device in loop back mode or normal mode
		if(arg){
			MCP2510_Write(CLKCTRL, MODE_LOOPBACK| CLKEN | CLK1);
			mcp2510dev.loopbackmode=1;
		}
		else{
			MCP2510_Write(CLKCTRL, MODE_NORMAL| CLKEN | CLK1);
			mcp2510dev.loopbackmode=0;
		}

		break;
	case UPCAN_IOCTRL_SETFILTER://set a filter for can device
		MCP2510_SetFilter((PCanFilter)arg);
		break;
	}
	
	local_irq_restore(flags);
	
	DPRINTK("IO control command=0x%x\n", cmd);
	return 0;
}

/***************************************************************\
*	write and send Can data interface for can device	 file					*
*	there are 2 mode for send data:									*
*		1, if write data size = sizeof(CanData) then send a full can frame	*
*		2, if write data size <=8 then send can data,					*
*		    we must set frame id first									*
\****************************************************************/
static ssize_t s3c44b0_mcp2510_write(struct file *file, const char *buffer, 
				    size_t count, loff_t * ppos)
{
	char sendbuffer[sizeof(CanData)];

	if(count==sizeof(CanData)){
		//send full Can frame---frame id and frame data
		copy_from_user(sendbuffer, buffer, sizeof(CanData));
		MCP2510_canWrite((PCanData)sendbuffer);

		DPRINTK("Send a Full Frame\n");
		return count;
	}

	if(count>8)
		return 0;

	//count <= 8

	copy_from_user(sendbuffer, buffer, count);
	MCP2510_canWriteData(sendbuffer, count);

	DPRINTK("Send data size=%d\n", count);
        DPRINTK("data=%x,%x,%x,%x,%x,%x,%x,%x\n",
		sendbuffer[0],sendbuffer[1],sendbuffer[2],sendbuffer[3],
		sendbuffer[4],sendbuffer[5],sendbuffer[6],sendbuffer[7]);
	return count;
}

static int RevRead(CanData *candata_ret)
{
	spin_lock_irq(&(mcp2510dev.lock));

	memcpy(candata_ret, 
		&(mcp2510dev.MCP2510_Candata[mcp2510dev.nCanReadpos]), 
		sizeof(CanData));
	NextCanDataPos(mcp2510dev.nCanReadpos);

	spin_unlock_irq(&(mcp2510dev.lock));

	return sizeof(CanData);
}


static ssize_t s3c44b0_mcp2510_read(struct file *filp, char *buffer, size_t count, loff_t *ppos)
{
	CanData candata_ret;

retry: 
	if (mcp2510dev.nCanReadpos !=  mcp2510dev.nCanRevpos) {
		int count;
		count = RevRead(&candata_ret);
		if (count) copy_to_user(buffer, (char *)&candata_ret, count);
		DPRINTK("read data size=%d\n", count);
		DPRINTK("id=%x, data=%x,%x,%x,%x,%x,%x,%x,%x\n", 
			candata_ret.id, candata_ret.data[0],
			candata_ret.data[1], candata_ret.data[2], 
			candata_ret.data[3], candata_ret.data[4],
			candata_ret.data[5], candata_ret.data[6],
			candata_ret.data[7]);
		return count;
	} else {
		if (filp->f_flags & O_NONBLOCK)
			return -EAGAIN;
		interruptible_sleep_on(&(mcp2510dev.wq));
		if (signal_pending(current))
			return -ERESTARTSYS;
		goto retry;
	}

	DPRINTK("read data size=%d\n", sizeof(candata_ret));
	return sizeof(candata_ret);
}

static int s3c44b0_mcp2510_open(struct inode *inode, struct file *file)
{
	int i,j,a;

	if(opencount==1)
		return -EBUSY;
	opencount++;

	memset(&mcp2510dev, 0 ,sizeof(mcp2510dev));

	init_waitqueue_head(&(mcp2510dev.wq));

	//Enable clock output
	MCP2510_Write(CLKCTRL, MODE_NORMAL| CLKEN | CLK1);
	// Clear, deactivate the three transmit buffers
	a = TXB0CTRL;
	for (i = 0; i < 3; i++) {
		for (j = 0; j < 14; j++) {
			MCP2510_Write(a, 0);
			a++;
	        }
	       	a += 2; // We did not clear CANSTAT or CANCTRL
	}
	// and the two receive buffers.
	MCP2510_Write(RXB0CTRL, 0);
	MCP2510_Write(RXB1CTRL, 0);

	//Open Interrupt
	MCP2510_Write(CANINTE, RX0IE|RX1IE);
	MCP2510_Setup(NULL);

	MCP2510_OPEN_INT();

	MOD_INC_USE_COUNT;
	DPRINTK("device open\n");
	return 0;
}

static int s3c44b0_mcp2510_release(struct inode *inode, struct file *filp)
{
	opencount--;

	MCP2510_Write(CANINTE, NO_IE);
	MCP2510_Write(CLKCTRL, MODE_LOOPBACK| CLKEN | CLK1);

	MCP2510_CLOSE_INT();

	MOD_DEC_USE_COUNT;
	DPRINTK("device release\n");
	return 0;
}

static struct file_operations s3c44b0_fops = {
	owner:	THIS_MODULE,
	write:	s3c44b0_mcp2510_write,
	read:	s3c44b0_mcp2510_read,
	ioctl:	s3c44b0_mcp2510_ioctl,
	open:	s3c44b0_mcp2510_open,
	release:	s3c44b0_mcp2510_release,
};

#ifdef CONFIG_DEVFS_FS
static devfs_handle_t devfs_spi_dir, devfs_spiraw;
#endif

static int __init s3c44b0_mcp2510_init(void)
{
	int ret;
	int flags;

	local_irq_save(flags);

	EXTINT &= ~(0xf<<(24));	//EINT6 low level
	MCP2510_CLOSE_INT();

	init_MCP2510(BandRate_250kbps);
	local_irq_restore(flags);

	ret = register_chrdev(0, DEVICE_NAME, &s3c44b0_fops);
	if (ret < 0) {
		printk(DEVICE_NAME " can't get major number\n");
		return ret;
	}
	tsMajor = ret;

	/* Enable touch interrupt */
	ret = request_irq(IRQ_MCP2510, s3c44b0_isr_mcp2510, SA_INTERRUPT, 
			  DEVICE_NAME, s3c44b0_isr_mcp2510);
	if (ret) 	return ret;


#ifdef CONFIG_DEVFS_FS
	devfs_spi_dir = devfs_mk_dir(NULL, "can", NULL);
	devfs_spiraw = devfs_register(devfs_spi_dir, "0", DEVFS_FL_DEFAULT,
			tsMajor, SPIRAW_MINOR, S_IFCHR | S_IRUSR | S_IWUSR,
			&s3c44b0_fops, NULL);
#endif

	printk(DEVICE_NAME " initialized\n");

	return 0;
}

static void __exit s3c44b0_mcp2510_exit(void)
{

	printk(DEVICE_NAME " unloaded\n");
}

module_init(s3c44b0_mcp2510_init);
module_exit(s3c44b0_mcp2510_exit);