mcp2515.c

spi接口的 LINUX CAN driver

	dev_dbg(&spi->dev, "%s: failed: ret = %d\n", __FUNCTION__, ret);

    frame->header.id = (rx_buf[0] << 3) | (rx_buf[1] >> 5);
    frame->header.ide = (rx_buf[1] >> 3) & 0x1;
    frame->header.srr = (rx_buf[1] >> 4) & 0x1;
    if (frame->header.ide == 1)
	frame->header.eid = (rx_buf[1] << 16) | (rx_buf[2] << 8) | rx_buf[3];
    else
	frame->header.eid = 0;
    frame->header.rtr = (rx_buf[4] >> 6) & 0x1;
    frame->header.rb1 = (rx_buf[4] >> 5) & 0x1;
    frame->header.rb0 = (rx_buf[4] >> 4) & 0x1;
    frame->header.dlc = rx_buf[4] & 0x0f;
    memcpy(frame->data, rx_buf + 5, CAN_FRAME_MAX_DATA_LEN);

    up(&chip->lock);

    /* update pos of ring buffer */
    chip->rxbin++;
    if (chip->rxbin >= MCP251X_BUF_LEN)
	chip->rxbin = 0;
			
    up(&chip->rxblock);

    return 0;
}

/* ........................................................................ */

/* bottom half task for interrupt */
#if (LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,20))
static void mcp251x_irq_handler(struct work_struct *work)
{
    struct mcp251x *chip = container_of(work, struct mcp251x, irq_work);
    struct spi_device *spi = chip->spi;
#else
static void mcp251x_irq_handler(void *dev_id)
{
    struct spi_device *spi = dev_id;
    struct mcp251x *chip = dev_get_drvdata(&spi->dev);
#endif
    uint8_t intf, rxs;

    for(;;) {
		
	intf = mcp251x_read_reg(spi, CANINTF);
	if (intf == 0x00)
	    break;

	dev_dbg(&spi->dev, "interrupt:%s%s%s%s%s%s%s%s\n",
		(intf & CANINTF_MERRF) ? " MERR":"",
		(intf & CANINTF_WAKIF) ? " WAK":"",
		(intf & CANINTF_ERRIF) ? " ERR":"",
		(intf & CANINTF_TX2IF) ? " TX2":"",
		(intf & CANINTF_TX1IF) ? " TX1":"",
		(intf & CANINTF_TX0IF) ? " TX0":"",
		(intf & CANINTF_RX1IF) ? " RX1":"",
		(intf & CANINTF_RX0IF) ? " RX0":"");
			
	rxs = mcp251x_read_state(spi, INSTRUCTION_RX_STATE); 
	dev_dbg(&spi->dev, "rx_state:%s%s\n",
		(rxs & RX_STATE_IDE) ? " IDE":"",
		(rxs & RX_STATE_RTR) ? " RTR":"");
			
	if (intf & CANINTF_MERRF) {
#if 0
	    uint8_t txbnctrl;
	    /* if there are no pending Tx buffers, restart queue */
	    txbnctrl = mcp251x_read_reg(spi, TXBCTRL(0));
	    if (!(txbnctrl & TXBCTRL_TXREQ))
		netif_wake_queue(&chip->can->ndev);
#endif
	}
	if (intf & CANINTF_ERRIF) {
	    uint8_t eflg = mcp251x_read_reg(spi, EFLG);
	    
	    dev_dbg(&spi->dev, "EFLG = 0x%02x\n", eflg);
	    
	    if (eflg & (EFLG_RX0OVR | EFLG_RX1OVR)) {
#if 0
		if (eflg & EFLG_RX0OVR)
		    chip->stats.rx_over_errors++;
		if (eflg & EFLG_RX1OVR)
		    chip->stats.rx_over_errors++;
#endif
		    mcp251x_write_reg(spi, EFLG, 0x00);
	    }
	}

	if (intf & CANINTF_TX0IF) /* If ready to send, copy data to send buffer. */
	    mcp251x_hw_tx(spi, 0);
	if (intf & CANINTF_TX1IF)
	    mcp251x_hw_tx(spi, 1);
	if (intf & CANINTF_TX2IF)
	    mcp251x_hw_tx(spi, 2);
	if (intf & CANINTF_RX0IF) /* If received data, copy data to ring buffer. */
	    mcp251x_hw_rx(spi, 0);
	if (intf & CANINTF_RX1IF)
	    mcp251x_hw_rx(spi, 1);
	
	mcp251x_write_bits(spi, CANINTF, intf, 0x00);
	
	/* If ring buffer of receive is not empty, wake up the read queue. */
	if (chip->rxbin != chip->rxbout)
	    wake_up_interruptible(&chip->wq);
    }
}


static irqreturn_t mcp251x_irq(int irq, void *dev_id, struct pt_regs *regs)
{
    struct spi_device *spi = dev_id;
    struct mcp251x *chip = dev_get_drvdata(&spi->dev);

    /* Can't do anything in interrupt context so fire of the interrupt
     * handling workqueue. */
    schedule_work(&chip->irq_work);

    return IRQ_HANDLED;
}

/* ........................................................................ */

static int mcp251x_open(struct inode *inode, struct file *file)
{
    struct mcp251x *chip = container_of(inode->i_cdev, struct mcp251x, cdev);
    struct spi_device *spi = chip->spi;
    struct mcp251x_platform_data *pdata = spi->dev.platform_data;
	
    file->private_data = chip;

    if (!chip->count) {
		
	if (pdata->transceiver_enable)
	    pdata->transceiver_enable(1);

	mcp251x_hw_wakeup(spi);

	/* Enable interrupts */
	mcp251x_write_reg(spi, CANINTE,
			  CANINTE_ERRIE | CANINTE_TX2IE
			  | CANINTE_TX1IE | CANINTE_TX0IE
			  | CANINTE_RX1IE | CANINTE_RX0IE);

	/* put device into normal mode */
	mcp251x_write_reg(spi, CANCTRL, CANCTRL_REQOP_NORMAL);
	mcp251x_write_reg(spi, RXBCTRL(0), RXBCTRL_BULK);
    }
	
    chip->count++;
	
    return 0;
}

static int mcp251x_release(struct inode *inode, struct file *file)
{
	
    struct mcp251x *chip = container_of(inode->i_cdev, struct mcp251x, cdev);
    struct spi_device *spi = chip->spi;
    struct mcp251x_platform_data *pdata = spi->dev.platform_data;

    chip->count--;
	
    if (chip->count)
	return 0;

    /* disable and clear pending interrupts */
    mcp251x_write_reg(spi, CANINTE, 0x00);
    mcp251x_write_reg(spi, CANINTF, 0x00);

    /* go to sleep */
    mcp251x_hw_sleep(spi);

    if (pdata->transceiver_enable)
	pdata->transceiver_enable(0);
		

    return 0;
}

static int mcp251x_write(struct file *file, const char __user *buf, size_t count, loff_t *ofs)
{
	
    struct mcp251x *chip = file->private_data;
    struct spi_device *spi = chip->spi;
    struct can_frame *frame;
    int ret;
    uint8_t txreq;

    if (count < sizeof(struct can_frame))
	return -EINVAL;

    if (down_interruptible(&chip->txblock))
	return -ERESTARTSYS;
	
    frame = &chip->txb[chip->txbin];
    ret = copy_from_user(frame, buf, sizeof(struct can_frame));
    chip->txbin++;
    if (chip->txbin >= MCP251X_BUF_LEN)
	chip->txbin = 0;
	
    up(&chip->txblock);
	
    txreq = mcp251x_read_state(spi, INSTRUCTION_CAN_STATE);
    if (!(txreq & CAN_STATE_TX0REQ))
	mcp251x_hw_tx(spi, 0);
		
    if (!(txreq & CAN_STATE_TX1REQ))
	mcp251x_hw_tx(spi, 1);

    if (!(txreq & CAN_STATE_TX2REQ))
	mcp251x_hw_tx(spi, 2);
	
    return count;
}

static ssize_t mcp251x_read(struct file *file, char __user *buf, size_t count, loff_t *ofs)
{
	
    struct mcp251x *chip = file->private_data;
    struct can_frame *frame;
	
    if (count != sizeof(struct can_frame))
	return -EINVAL;
		
    if (down_interruptible(&chip->rxblock))
	return -ERESTARTSYS;
	
    while (chip->rxbin == chip->rxbout) {
	up(&chip->rxblock);
	if (file->f_flags & O_NONBLOCK)
	    return -EAGAIN;
	if (wait_event_interruptible(chip->wq, (chip->rxbin != chip->rxbout)))
	    return -ERESTARTSYS;
	if (down_interruptible(&chip->rxblock))
	    return -ERESTARTSYS;
    }
	
    frame = &chip->rxb[chip->rxbout];
    if (copy_to_user(buf, frame, sizeof(struct can_frame))) {
	up(&chip->rxblock);
	return -EFAULT;
    }
	
    chip->rxbout++;
    if(chip->rxbout >= MCP251X_BUF_LEN)
	chip->rxbout = 0;
		
    up(&chip->rxblock);
		
    return count;
    
#if 0
retry:
    if (chip->rxbin != chip->rxbout) {
		
	down(&chip->rxblock);
		
	frame = &chip->rxb[chip->rxbout];
	if (copy_to_user(buf, frame, sizeof(struct can_frame))) {
	    up(&chip->rxblock);
	    return -EFAULT;
	}
	chip->rxbout++;
	if(chip->rxbout >= MCP251X_BUF_LEN)
	    chip->rxbout = 0;
		
	up(&chip->rxblock);
		
	return count;
    }
    else {
	if (file->f_flags & O_NONBLOCK)
	    return -EAGAIN;
	interruptible_sleep_on(&chip->wq);
	if (signal_pending(current))
	    return -ERESTARTSYS;
			
	goto retry;
    }
#endif
}

static int mcp251x_ioctl(struct inode *inode, struct file *file, 
			 unsigned int cmd, unsigned long arg)
{

    struct mcp251x *chip = container_of(inode->i_cdev, struct mcp251x, cdev);
    struct spi_device *spi = chip->spi;
    int ret = 0;

    switch(cmd) {
	
    case CAN_IOCTRESET:		/* reset devcie */
	mcp251x_hw_reset(spi);
	break;
    case CAN_IOCTWAKEUP:	/* wake up device */
	mcp251x_hw_wakeup(spi);
	break;
    case CAN_IOCSRATE:		/* set bit rate */
	ret = mcp251x_set_bit_rate(spi, (int)arg);
	mdelay(10);
	break;
    case CAN_IOCGRATE:		/* get bit rate */
	*((int *)arg) = mcp251x_get_bit_rate(spi);
	break;
    case CAN_IOCSFILTER:	/* set filter */
	ret = mcp251x_set_filter(spi, (struct can_filter *)arg);
	break;
    case CAN_IOCGFILTER:	/* get filter */
	ret = mcp251x_get_filter(spi, (struct can_filter *)arg);
	break;
    case CAN_IOCTNORMALMODE:	/* turn to normal mode */
	mcp251x_write_bits(spi, CANCTRL, CANCTRL_REQOP_MASK, CANCTRL_REQOP_NORMAL);
	break;
    case CAN_IOCTLOOPBACKMODE:	/* turn to loopback mode */
	mcp251x_write_bits(spi, CANCTRL, CANCTRL_REQOP_MASK, CANCTRL_REQOP_LOOPBACK);
	break;
    case CAN_IOCTLISTENONLYMODE: /* turn to listen only mode */
	mcp251x_write_bits(spi, CANCTRL, CANCTRL_REQOP_MASK, CANCTRL_REQOP_LISTEN_ONLY);
	break;
    case CAN_IOCTSLEEPMODE:	/* turn to sleep mode */
	mcp251x_hw_sleep(spi);
	break;
    default:
	return -ENOTTY;
    }
	
    return ret;
}


static const struct file_operations mcp251x_fops = {
    .owner = THIS_MODULE,
    .read = mcp251x_read,
    .write = mcp251x_write,
    .ioctl = mcp251x_ioctl,
    .open = mcp251x_open,
    .release = mcp251x_release,
};

/* ........................................................................ */

static int mcp251x_remove(struct spi_device *spi)
{
    struct mcp251x *chip = dev_get_drvdata(&spi->dev);

    dev_dbg(&spi->dev, "%s: stop\n",  __FUNCTION__);

    cdev_del(&chip->cdev);
    free_irq(spi->irq, spi);
    kfree(chip->spi_transfer_buf);

    return 0;
}

static int __devinit mcp251x_probe(struct spi_device *spi)
{
    struct mcp251x *chip;
    int ret = 0;

    dev_dbg(&spi->dev, "%s: start\n",  __FUNCTION__);

    chip = kmalloc(sizeof(struct mcp251x), GFP_KERNEL);
    if (!chip) {
	ret = -ENOMEM;
	goto error_alloc;
    }

    dev_set_drvdata(&spi->dev, chip);
	
    chip->txbin = chip->txbout = 0;
    chip->rxbin = chip->rxbout = 0;
    chip->count = 0;
    chip->spi = spi;
    init_MUTEX(&chip->lock);
    init_MUTEX(&chip->txblock);
    init_MUTEX(&chip->rxblock);
    init_waitqueue_head(&chip->wq);
    
#if (LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,20))
    INIT_WORK(&chip->irq_work, mcp251x_irq_handler);
#else
    INIT_WORK(&chip->irq_work, mcp251x_irq_handler, spi);
#endif
    
    chip->spi_transfer_buf = kmalloc(SPI_TRANSFER_BUF_LEN, GFP_KERNEL);
    if (!chip->spi_transfer_buf) {
	ret = -ENOMEM;
	goto error_buf;
    }
	
    ret = request_irq(spi->irq, mcp251x_irq, SA_SAMPLE_RANDOM, DRIVER_NAME, spi);
    if (ret < 0) {
	dev_err(&spi->dev, "request irq %d failed (ret = %d)\n", spi->irq, ret);
	goto error_irq;
    }

    if (can_minor > CAN_MAX_DEV)
	goto error_register;
		
    if (can_major) {
	devid = MKDEV(can_major, ++can_minor);
	ret = register_chrdev_region(devid, 0, DRIVER_NAME);
    } else {
	ret = alloc_chrdev_region(&devid, can_minor, 0, DRIVER_NAME);
	can_major = MAJOR(devid);
    }
	
    if (ret < 0) {
	dev_err(&spi->dev, "register char device region (%d:%d) failed (ret = %d)\n", MAJOR(devid), MINOR(devid), ret);
	goto error_register;
    }
	
    cdev_init(&chip->cdev, &mcp251x_fops);
    chip->cdev.owner = THIS_MODULE;
    ret = cdev_add(&chip->cdev, devid, 1);
    if (ret < 0) {
	dev_err(&spi->dev, "register char device failed (ret = %d)\n", ret);
	goto error_devadd;
    }
	
    dev_info(&spi->dev, "device register at dev(%d:%d)\n", MAJOR(devid), MINOR(devid));
	
    mcp251x_hw_init(spi);
    mcp251x_set_bit_rate(spi, 125000); /* A reasonable default */
    mcp251x_hw_sleep(spi);

    return 0;
	
error_devadd:
    unregister_chrdev_region(devid, 0);
error_register:
    free_irq(spi->irq, spi);
error_irq:
    kfree(chip->spi_transfer_buf);
error_buf:
    kfree(chip);
error_alloc:
    return ret;
}

#ifdef CONFIG_PM
static int mcp251x_suspend(struct spi_device *spi, pm_message_t mesg)
{
    struct mcp251x *chip = dev_get_drvdata(&spi->dev);
    struct mcp251x_platform_data *pdata = spi->dev.platform_data;

    if (chip->count)
	return 0;

    mcp251x_hw_sleep(spi);
    if (pdata->transceiver_enable)
	pdata->transceiver_enable(0);

    return 0;
}

static int mcp251x_resume(struct spi_device *spi)
{
    struct mcp251x *chip = dev_get_drvdata(&spi->dev);
    struct mcp251x_platform_data *pdata = spi->dev.platform_data;

    if (!chip->count)
	return 0;
		
    if (pdata->transceiver_enable)
	pdata->transceiver_enable(1);
    mcp251x_hw_wakeup(spi);

    return 0;
}
#endif

static struct spi_driver mcp251x_driver = {
    .driver = {
	.name	= DRIVER_NAME,
	.bus	= &spi_bus_type,
	.owner	= THIS_MODULE,
    },
    .probe	= mcp251x_probe,
    .remove	= __devexit_p(mcp251x_remove),
#ifdef CONFIG_PM
    .suspend	= mcp251x_suspend,
    .resume	= mcp251x_resume,
#endif
};

static int __init mcp251x_init(void)
{
    return spi_register_driver(&mcp251x_driver);
}
module_init(mcp251x_init);

static void __exit mcp251x_exit(void)
{
    spi_unregister_driver(&mcp251x_driver);
}
module_exit(mcp251x_exit);


MODULE_DESCRIPTION("MCP251x CAN controller driver");
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Renzhou.Meng");