pl2303.c

底层驱动开发

			kfree(priv);
			usb_set_serial_port_data(serial->port[i], NULL);
		}
	}		
}

static void pl2303_update_line_status(struct usb_serial_port *port,
				      unsigned char *data,
				      unsigned int actual_length)
{

	struct pl2303_private *priv = usb_get_serial_port_data(port);
	unsigned long flags;
	u8 status_idx = UART_STATE;
	u8 length = UART_STATE;

	if ((le16_to_cpu(port->serial->dev->descriptor.idVendor) == SIEMENS_VENDOR_ID) &&
	    (le16_to_cpu(port->serial->dev->descriptor.idProduct) == SIEMENS_PRODUCT_ID_X65)) {
		length = 1;
		status_idx = 0;
	}

	if (actual_length < length)
		goto exit;

        /* Save off the uart status for others to look at */
	spin_lock_irqsave(&priv->lock, flags);
	priv->line_status = data[status_idx];
	spin_unlock_irqrestore(&priv->lock, flags);

exit:
	return;
}

static void pl2303_read_int_callback (struct urb *urb, struct pt_regs *regs)
{
	struct usb_serial_port *port = (struct usb_serial_port *) urb->context;
	unsigned char *data = urb->transfer_buffer;
	unsigned int actual_length = urb->actual_length;
	int status;

	dbg("%s (%d)", __FUNCTION__, port->number);

	switch (urb->status) {
	case 0:
		/* success */
		break;
	case -ECONNRESET:
	case -ENOENT:
	case -ESHUTDOWN:
		/* this urb is terminated, clean up */
		dbg("%s - urb shutting down with status: %d", __FUNCTION__, urb->status);
		return;
	default:
		dbg("%s - nonzero urb status received: %d", __FUNCTION__, urb->status);
		goto exit;
	}

	usb_serial_debug_data(debug, &port->dev, __FUNCTION__, urb->actual_length, urb->transfer_buffer);
	pl2303_update_line_status(port, data, actual_length);

exit:
	status = usb_submit_urb (urb, GFP_ATOMIC);
	if (status)
		dev_err(&urb->dev->dev, "%s - usb_submit_urb failed with result %d\n",
			__FUNCTION__, status);
}


static void pl2303_read_bulk_callback (struct urb *urb, struct pt_regs *regs)
{
	struct usb_serial_port *port = (struct usb_serial_port *) urb->context;
	struct pl2303_private *priv = usb_get_serial_port_data(port);
	struct tty_struct *tty;
	unsigned char *data = urb->transfer_buffer;
	unsigned long flags;
	int i;
	int result;
	u8 status;
	char tty_flag;

	dbg("%s - port %d", __FUNCTION__, port->number);

	if (urb->status) {
		dbg("%s - urb->status = %d", __FUNCTION__, urb->status);
		if (!port->open_count) {
			dbg("%s - port is closed, exiting.", __FUNCTION__);
			return;
		}
		if (urb->status == -EPROTO) {
			/* PL2303 mysteriously fails with -EPROTO reschedule the read */
			dbg("%s - caught -EPROTO, resubmitting the urb", __FUNCTION__);
			urb->status = 0;
			urb->dev = port->serial->dev;
			result = usb_submit_urb(urb, GFP_ATOMIC);
			if (result)
				dev_err(&urb->dev->dev, "%s - failed resubmitting read urb, error %d\n", __FUNCTION__, result);
			return;
		}
		dbg("%s - unable to handle the error, exiting.", __FUNCTION__);
		return;
	}

	usb_serial_debug_data(debug, &port->dev, __FUNCTION__, urb->actual_length, data);

	/* get tty_flag from status */
	tty_flag = TTY_NORMAL;

	spin_lock_irqsave(&priv->lock, flags);
	status = priv->line_status;
	priv->line_status &= ~UART_STATE_TRANSIENT_MASK;
	spin_unlock_irqrestore(&priv->lock, flags);
	wake_up_interruptible (&priv->delta_msr_wait);

	/* break takes precedence over parity, */
	/* which takes precedence over framing errors */
	if (status & UART_BREAK_ERROR )
		tty_flag = TTY_BREAK;
	else if (status & UART_PARITY_ERROR)
		tty_flag = TTY_PARITY;
	else if (status & UART_FRAME_ERROR)
		tty_flag = TTY_FRAME;
	dbg("%s - tty_flag = %d", __FUNCTION__, tty_flag);

	tty = port->tty;
	if (tty && urb->actual_length) {
		/* overrun is special, not associated with a char */
		if (status & UART_OVERRUN_ERROR)
			tty_insert_flip_char(tty, 0, TTY_OVERRUN);

		for (i = 0; i < urb->actual_length; ++i) {
			if (tty->flip.count >= TTY_FLIPBUF_SIZE) {
				tty_flip_buffer_push(tty);
			}
			tty_insert_flip_char (tty, data[i], tty_flag);
		}
		tty_flip_buffer_push (tty);
	}

	/* Schedule the next read _if_ we are still open */
	if (port->open_count) {
		urb->dev = port->serial->dev;
		result = usb_submit_urb(urb, GFP_ATOMIC);
		if (result)
			dev_err(&urb->dev->dev, "%s - failed resubmitting read urb, error %d\n", __FUNCTION__, result);
	}

	return;
}



static void pl2303_write_bulk_callback (struct urb *urb, struct pt_regs *regs)
{
	struct usb_serial_port *port = (struct usb_serial_port *) urb->context;
	struct pl2303_private *priv = usb_get_serial_port_data(port);
	int result;

	dbg("%s - port %d", __FUNCTION__, port->number);

	switch (urb->status) {
	case 0:
		/* success */
		break;
	case -ECONNRESET:
	case -ENOENT:
	case -ESHUTDOWN:
		/* this urb is terminated, clean up */
		dbg("%s - urb shutting down with status: %d", __FUNCTION__, urb->status);
		priv->write_urb_in_use = 0;
		return;
	default:
		/* error in the urb, so we have to resubmit it */
		dbg("%s - Overflow in write", __FUNCTION__);
		dbg("%s - nonzero write bulk status received: %d", __FUNCTION__, urb->status);
		port->write_urb->transfer_buffer_length = 1;
		port->write_urb->dev = port->serial->dev;
		result = usb_submit_urb (port->write_urb, GFP_ATOMIC);
		if (result)
			dev_err(&urb->dev->dev, "%s - failed resubmitting write urb, error %d\n", __FUNCTION__, result);
		else
			return;
	}

	priv->write_urb_in_use = 0;

	/* send any buffered data */
	pl2303_send(port);
}


/*
 * pl2303_buf_alloc
 *
 * Allocate a circular buffer and all associated memory.
 */

static struct pl2303_buf *pl2303_buf_alloc(unsigned int size)
{

	struct pl2303_buf *pb;


	if (size == 0)
		return NULL;

	pb = (struct pl2303_buf *)kmalloc(sizeof(struct pl2303_buf), GFP_KERNEL);
	if (pb == NULL)
		return NULL;

	pb->buf_buf = kmalloc(size, GFP_KERNEL);
	if (pb->buf_buf == NULL) {
		kfree(pb);
		return NULL;
	}

	pb->buf_size = size;
	pb->buf_get = pb->buf_put = pb->buf_buf;

	return pb;

}


/*
 * pl2303_buf_free
 *
 * Free the buffer and all associated memory.
 */

static void pl2303_buf_free(struct pl2303_buf *pb)
{
	if (pb) {
		kfree(pb->buf_buf);
		kfree(pb);
	}
}


/*
 * pl2303_buf_clear
 *
 * Clear out all data in the circular buffer.
 */

static void pl2303_buf_clear(struct pl2303_buf *pb)
{
	if (pb != NULL)
		pb->buf_get = pb->buf_put;
		/* equivalent to a get of all data available */
}


/*
 * pl2303_buf_data_avail
 *
 * Return the number of bytes of data available in the circular
 * buffer.
 */

static unsigned int pl2303_buf_data_avail(struct pl2303_buf *pb)
{
	if (pb != NULL)
		return ((pb->buf_size + pb->buf_put - pb->buf_get) % pb->buf_size);
	else
		return 0;
}


/*
 * pl2303_buf_space_avail
 *
 * Return the number of bytes of space available in the circular
 * buffer.
 */

static unsigned int pl2303_buf_space_avail(struct pl2303_buf *pb)
{
	if (pb != NULL)
		return ((pb->buf_size + pb->buf_get - pb->buf_put - 1) % pb->buf_size);
	else
		return 0;
}


/*
 * pl2303_buf_put
 *
 * Copy data data from a user buffer and put it into the circular buffer.
 * Restrict to the amount of space available.
 *
 * Return the number of bytes copied.
 */

static unsigned int pl2303_buf_put(struct pl2303_buf *pb, const char *buf,
	unsigned int count)
{

	unsigned int len;


	if (pb == NULL)
		return 0;

	len  = pl2303_buf_space_avail(pb);
	if (count > len)
		count = len;

	if (count == 0)
		return 0;

	len = pb->buf_buf + pb->buf_size - pb->buf_put;
	if (count > len) {
		memcpy(pb->buf_put, buf, len);
		memcpy(pb->buf_buf, buf+len, count - len);
		pb->buf_put = pb->buf_buf + count - len;
	} else {
		memcpy(pb->buf_put, buf, count);
		if (count < len)
			pb->buf_put += count;
		else /* count == len */
			pb->buf_put = pb->buf_buf;
	}

	return count;

}


/*
 * pl2303_buf_get
 *
 * Get data from the circular buffer and copy to the given buffer.
 * Restrict to the amount of data available.
 *
 * Return the number of bytes copied.
 */

static unsigned int pl2303_buf_get(struct pl2303_buf *pb, char *buf,
	unsigned int count)
{

	unsigned int len;


	if (pb == NULL)
		return 0;

	len = pl2303_buf_data_avail(pb);
	if (count > len)
		count = len;

	if (count == 0)
		return 0;

	len = pb->buf_buf + pb->buf_size - pb->buf_get;
	if (count > len) {
		memcpy(buf, pb->buf_get, len);
		memcpy(buf+len, pb->buf_buf, count - len);
		pb->buf_get = pb->buf_buf + count - len;
	} else {
		memcpy(buf, pb->buf_get, count);
		if (count < len)
			pb->buf_get += count;
		else /* count == len */
			pb->buf_get = pb->buf_buf;
	}

	return count;

}

static int __init pl2303_init (void)
{
	int retval;
	retval = usb_serial_register(&pl2303_device);
	if (retval)
		goto failed_usb_serial_register;
	retval = usb_register(&pl2303_driver);
	if (retval)
		goto failed_usb_register;
	info(DRIVER_DESC " " DRIVER_VERSION);
	return 0;
failed_usb_register:
	usb_serial_deregister(&pl2303_device);
failed_usb_serial_register:
	return retval;
}


static void __exit pl2303_exit (void)
{
	usb_deregister (&pl2303_driver);
	usb_serial_deregister (&pl2303_device);
}


module_init(pl2303_init);
module_exit(pl2303_exit);

MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_VERSION(DRIVER_VERSION);
MODULE_LICENSE("GPL");

module_param(debug, bool, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(debug, "Debug enabled or not");