oti6858.c

linux 内核源代码

	dbg("%s()", __FUNCTION__);

	for (i = 0; i < serial->num_ports; ++i) {
		priv = usb_get_serial_port_data(serial->port[i]);
		if (priv) {
			pl2303_buf_free(priv->buf);
			kfree(priv);
			usb_set_serial_port_data(serial->port[i], NULL);
		}
	}
}

static void oti6858_read_int_callback(struct urb *urb)
{
	struct usb_serial_port *port = (struct usb_serial_port *) urb->context;
	struct oti6858_private *priv = usb_get_serial_port_data(port);
	int transient = 0, can_recv = 0, resubmit = 1;
	int status = urb->status;

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

	switch (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__, status);
		return;
	default:
		dbg("%s(): nonzero urb status received: %d",
					__FUNCTION__, status);
		break;
	}

	if (status == 0 && urb->actual_length == OTI6858_CTRL_PKT_SIZE) {
		struct oti6858_control_pkt *xs = urb->transfer_buffer;
		unsigned long flags;

		spin_lock_irqsave(&priv->lock, flags);

		if (!priv->transient) {
			if (!OTI6858_CTRL_EQUALS_PENDING(xs, priv)) {
				if (xs->rx_bytes_avail == 0) {
					priv->transient = 4;
					priv->setup_done = 0;
					resubmit = 0;
					dbg("%s(): scheduling setup_line()",
					    __FUNCTION__);
					schedule_delayed_work(&priv->delayed_setup_work, 0);
				}
			}
		} else {
			if (OTI6858_CTRL_EQUALS_PENDING(xs, priv)) {
				priv->transient = 0;
			} else if (!priv->setup_done) {
				resubmit = 0;
			} else if (--priv->transient == 0) {
				if (xs->rx_bytes_avail == 0) {
					priv->transient = 4;
					priv->setup_done = 0;
					resubmit = 0;
					dbg("%s(): scheduling setup_line()",
					    __FUNCTION__);
					schedule_delayed_work(&priv->delayed_setup_work, 0);
				}
			}
		}

		if (!priv->transient) {
			if (xs->pin_state != priv->status.pin_state)
				wake_up_interruptible(&priv->intr_wait);
			memcpy(&priv->status, xs, OTI6858_CTRL_PKT_SIZE);
		}

		if (!priv->transient && xs->rx_bytes_avail != 0) {
			can_recv = xs->rx_bytes_avail;
			priv->flags.read_urb_in_use = 1;
		}

		transient = priv->transient;
		spin_unlock_irqrestore(&priv->lock, flags);
	}

	if (can_recv) {
		int result;

		port->read_urb->dev = port->serial->dev;
		result = usb_submit_urb(port->read_urb, GFP_ATOMIC);
		if (result != 0) {
			priv->flags.read_urb_in_use = 0;
			dev_err(&port->dev, "%s(): usb_submit_urb() failed,"
					" error %d\n", __FUNCTION__, result);
		} else {
			resubmit = 0;
		}
	} else if (!transient) {
		unsigned long flags;

		spin_lock_irqsave(&priv->lock, flags);
		if (priv->flags.write_urb_in_use == 0
				&& pl2303_buf_data_avail(priv->buf) != 0) {
			schedule_delayed_work(&priv->delayed_write_work,0);
			resubmit = 0;
		}
		spin_unlock_irqrestore(&priv->lock, flags);
	}

	if (resubmit) {
		int result;

//		dbg("%s(): submitting interrupt urb", __FUNCTION__);
		urb->dev = port->serial->dev;
		result = usb_submit_urb(urb, GFP_ATOMIC);
		if (result != 0) {
			dev_err(&urb->dev->dev,
					"%s(): usb_submit_urb() failed with"
					" error %d\n", __FUNCTION__, result);
		}
	}
}

static void oti6858_read_bulk_callback(struct urb *urb)
{
	struct usb_serial_port *port = (struct usb_serial_port *) urb->context;
	struct oti6858_private *priv = usb_get_serial_port_data(port);
	struct tty_struct *tty;
	unsigned char *data = urb->transfer_buffer;
	unsigned long flags;
	int i, result;
	int status = urb->status;
	char tty_flag;

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

	spin_lock_irqsave(&priv->lock, flags);
	priv->flags.read_urb_in_use = 0;
	spin_unlock_irqrestore(&priv->lock, flags);

	if (status != 0) {
		if (!port->open_count) {
			dbg("%s(): port is closed, exiting", __FUNCTION__);
			return;
		}
		/*
		if (status == -EPROTO) {
			// PL2303 mysteriously fails with -EPROTO reschedule the read
			dbg("%s - caught -EPROTO, resubmitting the urb", __FUNCTION__);
			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;
	}

	// get tty_flag from status
	tty_flag = TTY_NORMAL;

/* FIXME: probably, errors will be signalled using interrupt pipe! */
/*
	// 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 != NULL && urb->actual_length > 0) {
		tty_buffer_request_room(tty, urb->actual_length);
		for (i = 0; i < urb->actual_length; ++i)
			tty_insert_flip_char(tty, data[i], tty_flag);
		tty_flip_buffer_push(tty);
	}

	// schedule the interrupt urb if we are still open */
	if (port->open_count != 0) {
		port->interrupt_in_urb->dev = port->serial->dev;
		result = usb_submit_urb(port->interrupt_in_urb, GFP_ATOMIC);
		if (result != 0) {
			dev_err(&port->dev, "%s(): usb_submit_urb() failed,"
					" error %d\n", __FUNCTION__, result);
		}
	}
}

static void oti6858_write_bulk_callback(struct urb *urb)
{
	struct usb_serial_port *port = (struct usb_serial_port *) urb->context;
	struct oti6858_private *priv = usb_get_serial_port_data(port);
	int status = urb->status;
	int result;

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

	switch (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__, status);
		priv->flags.write_urb_in_use = 0;
		return;
	default:
		/* error in the urb, so we have to resubmit it */
		dbg("%s(): nonzero write bulk status received: %d",
					__FUNCTION__, status);
		dbg("%s(): overflow in write", __FUNCTION__);

		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(&port->dev, "%s(): usb_submit_urb() failed,"
					" error %d\n", __FUNCTION__, result);
		} else {
			return;
		}
	}

	priv->flags.write_urb_in_use = 0;

	// schedule the interrupt urb if we are still open */
	port->interrupt_in_urb->dev = port->serial->dev;
	dbg("%s(): submitting interrupt urb", __FUNCTION__);
	result = usb_submit_urb(port->interrupt_in_urb, GFP_ATOMIC);
	if (result != 0) {
		dev_err(&port->dev, "%s(): failed submitting int urb,"
					" error %d\n", __FUNCTION__, result);
	}
}


/*
 * 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 = 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) {
		/* equivalent to a get of all data available */
		pb->buf_get = pb->buf_put;
	}
}

/*
 * 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 0;
	return ((pb->buf_size + pb->buf_put - pb->buf_get) % pb->buf_size);
}

/*
 * 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 0;
	return ((pb->buf_size + pb->buf_get - pb->buf_put - 1) % pb->buf_size);
}

/*
 * 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;
}

/* module description and (de)initialization */

static int __init oti6858_init(void)
{
	int retval;

	if ((retval = usb_serial_register(&oti6858_device)) == 0) {
		if ((retval = usb_register(&oti6858_driver)) != 0)
			usb_serial_deregister(&oti6858_device);
		else
			return 0;
	}

	return retval;
}

static void __exit oti6858_exit(void)
{
	usb_deregister(&oti6858_driver);
	usb_serial_deregister(&oti6858_device);
}

module_init(oti6858_init);
module_exit(oti6858_exit);

MODULE_DESCRIPTION(OTI6858_DESCRIPTION);
MODULE_AUTHOR(OTI6858_AUTHOR);
MODULE_VERSION(OTI6858_VERSION);
MODULE_LICENSE("GPL");

module_param(debug, bool, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(debug, "enable debug output");