ftdi_sio.c

標準的linux下rs-232驅動代碼,是2.6內核的.

	if (rv < 0) {
		dev_err(dev, "Unable to write latency timer: %i\n", rv);
		return -EIO;
	}

	return count;
}

/* Write an event character directly to the FTDI register.  The ASCII
   value is in the low 8 bits, with the enable bit in the 9th bit. */
static ssize_t store_event_char(struct device *dev, struct device_attribute *attr, const char *valbuf,
				size_t count)
{
	struct usb_serial_port *port = to_usb_serial_port(dev);
	struct ftdi_private *priv = usb_get_serial_port_data(port);
	struct usb_device *udev = port->serial->dev;
	char buf[1];
	int v = simple_strtoul(valbuf, NULL, 10);
	int rv = 0;

	dbg("%s: setting event char = %i", __FUNCTION__, v);

	rv = usb_control_msg(udev,
			     usb_sndctrlpipe(udev, 0),
			     FTDI_SIO_SET_EVENT_CHAR_REQUEST,
			     FTDI_SIO_SET_EVENT_CHAR_REQUEST_TYPE,
			     v, priv->interface,
			     buf, 0, WDR_TIMEOUT);

	if (rv < 0) {
		dbg("Unable to write event character: %i", rv);
		return -EIO;
	}

	return count;
}

static DEVICE_ATTR(latency_timer, S_IWUSR | S_IRUGO, show_latency_timer, store_latency_timer);
static DEVICE_ATTR(event_char, S_IWUSR, NULL, store_event_char);

static int create_sysfs_attrs(struct usb_serial_port *port)
{
	struct ftdi_private *priv = usb_get_serial_port_data(port);
	int retval = 0;

	dbg("%s",__FUNCTION__);

	/* XXX I've no idea if the original SIO supports the event_char
	 * sysfs parameter, so I'm playing it safe.  */
	if (priv->chip_type != SIO) {
		dbg("sysfs attributes for %s", ftdi_chip_name[priv->chip_type]);
		retval = device_create_file(&port->dev, &dev_attr_event_char);
		if ((!retval) &&
		    (priv->chip_type == FT232BM ||
		     priv->chip_type == FT2232C ||
		     priv->chip_type == FT232RL ||
		     priv->chip_type == FT2232H ||
		     priv->chip_type == FT4232H)) {
			retval = device_create_file(&port->dev,
						    &dev_attr_latency_timer);
		}
	}
	return retval;
}

static void remove_sysfs_attrs(struct usb_serial_port *port)
{
	struct ftdi_private *priv = usb_get_serial_port_data(port);

	dbg("%s",__FUNCTION__);

	/* XXX see create_sysfs_attrs */
	if (priv->chip_type != SIO) {
		device_remove_file(&port->dev, &dev_attr_event_char);
		if (priv->chip_type == FT232BM ||
		    priv->chip_type == FT2232C ||
		    priv->chip_type == FT232RL ||
		    priv->chip_type == FT2232H ||
		    priv->chip_type == FT4232H) {
			device_remove_file(&port->dev, &dev_attr_latency_timer);
		}
	}

}

/*
 * ***************************************************************************
 * FTDI driver specific functions
 * ***************************************************************************
 */

/* Probe function to check for special devices */
static int ftdi_sio_probe (struct usb_serial *serial, const struct usb_device_id *id)
{
	struct ftdi_sio_quirk *quirk = (struct ftdi_sio_quirk *)id->driver_info;

	if (quirk && quirk->probe) {
		int ret = quirk->probe(serial);
		if (ret != 0)
			return ret;
	}

	usb_set_serial_data(serial, (void *)id->driver_info);

	return 0;
}

static int ftdi_sio_port_probe(struct usb_serial_port *port)
{
	struct ftdi_private *priv;
	struct ftdi_sio_quirk *quirk = usb_get_serial_data(port->serial);


	dbg("%s",__FUNCTION__);

	priv = kzalloc(sizeof(struct ftdi_private), GFP_KERNEL);
	if (!priv){
		err("%s- kmalloc(%Zd) failed.", __FUNCTION__, sizeof(struct ftdi_private));
		return -ENOMEM;
	}

	spin_lock_init(&priv->rx_lock);
	spin_lock_init(&priv->tx_lock);
        init_waitqueue_head(&priv->delta_msr_wait);
	/* This will push the characters through immediately rather
	   than queue a task to deliver them */
	priv->flags = ASYNC_LOW_LATENCY;

	if (quirk && quirk->port_probe)
		quirk->port_probe(priv);

	/* Increase the size of read buffers */
	kfree(port->bulk_in_buffer);
	port->bulk_in_buffer = kmalloc (BUFSZ, GFP_KERNEL);
	if (!port->bulk_in_buffer) {
		kfree (priv);
		return -ENOMEM;
	}
	if (port->read_urb) {
		port->read_urb->transfer_buffer = port->bulk_in_buffer;
		port->read_urb->transfer_buffer_length = BUFSZ;
	}

	INIT_DELAYED_WORK(&priv->rx_work, ftdi_process_read);
	priv->port = port;

	/* Free port's existing write urb and transfer buffer. */
	if (port->write_urb) {
		usb_free_urb (port->write_urb);
		port->write_urb = NULL;
	}
	kfree(port->bulk_out_buffer);
	port->bulk_out_buffer = NULL;

	usb_set_serial_port_data(port, priv);

	ftdi_determine_type (port);
	create_sysfs_attrs(port);
	return 0;
}

/* Setup for the USB-UIRT device, which requires hardwired
 * baudrate (38400 gets mapped to 312500) */
/* Called from usbserial:serial_probe */
static void ftdi_USB_UIRT_setup (struct ftdi_private *priv)
{
	dbg("%s",__FUNCTION__);

	priv->flags |= ASYNC_SPD_CUST;
	priv->custom_divisor = 77;
	priv->force_baud = 38400;
} /* ftdi_USB_UIRT_setup */

/* Setup for the HE-TIRA1 device, which requires hardwired
 * baudrate (38400 gets mapped to 100000) and RTS-CTS enabled.  */
static void ftdi_HE_TIRA1_setup (struct ftdi_private *priv)
{
	dbg("%s",__FUNCTION__);

	priv->flags |= ASYNC_SPD_CUST;
	priv->custom_divisor = 240;
	priv->force_baud = 38400;
	priv->force_rtscts = 1;
} /* ftdi_HE_TIRA1_setup */

/*
 * First port on Olimex arm-usb-ocd is reserved for JTAG interface
 * and can be accessed from userspace using openocd.
 */
static int ftdi_olimex_probe(struct usb_serial *serial)
{
	struct usb_device *udev = serial->dev;
	struct usb_interface *interface = serial->interface;

	dbg("%s",__FUNCTION__);

	if (interface == udev->actconfig->interface[0]) {
		info("Ignoring reserved serial port on Olimex arm-usb-ocd\n");
		return -ENODEV;
	}

	return 0;
}

/* ftdi_shutdown is called from usbserial:usb_serial_disconnect
 *   it is called when the usb device is disconnected
 *
 *   usbserial:usb_serial_disconnect
 *      calls __serial_close for each open of the port
 *      shutdown is called then (ie ftdi_shutdown)
 */
static void ftdi_shutdown (struct usb_serial *serial)
{
	dbg("%s", __FUNCTION__);
}

static int ftdi_sio_port_remove(struct usb_serial_port *port)
{
	struct ftdi_private *priv = usb_get_serial_port_data(port);

	dbg("%s", __FUNCTION__);

	remove_sysfs_attrs(port);

	/* all open ports are closed at this point
         *    (by usbserial.c:__serial_close, which calls ftdi_close)
	 */

	if (priv) {
		usb_set_serial_port_data(port, NULL);
		kfree(priv);
	}

	return 0;
}

static int  ftdi_open (struct usb_serial_port *port, struct file *filp)
{ /* ftdi_open */
	struct usb_device *dev = port->serial->dev;
	struct ftdi_private *priv = usb_get_serial_port_data(port);
	unsigned long flags;

	int result = 0;
	char buf[1]; /* Needed for the usb_control_msg I think */

	dbg("%s", __FUNCTION__);

	spin_lock_irqsave(&priv->tx_lock, flags);
	priv->tx_bytes = 0;
	spin_unlock_irqrestore(&priv->tx_lock, flags);
	spin_lock_irqsave(&priv->rx_lock, flags);
	priv->rx_bytes = 0;
	spin_unlock_irqrestore(&priv->rx_lock, flags);

	if (port->tty)
		port->tty->low_latency = (priv->flags & ASYNC_LOW_LATENCY) ? 1 : 0;

	/* No error checking for this (will get errors later anyway) */
	/* See ftdi_sio.h for description of what is reset */
	usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
			FTDI_SIO_RESET_REQUEST, FTDI_SIO_RESET_REQUEST_TYPE,
			FTDI_SIO_RESET_SIO,
			priv->interface, buf, 0, WDR_TIMEOUT);

	/* Termios defaults are set by usb_serial_init. We don't change
	   port->tty->termios - this would loose speed settings, etc.
	   This is same behaviour as serial.c/rs_open() - Kuba */

	/* ftdi_set_termios  will send usb control messages */
	if (port->tty)
		ftdi_set_termios(port, port->tty->termios);

	/* FIXME: Flow control might be enabled, so it should be checked -
	   we have no control of defaults! */
	/* Turn on RTS and DTR since we are not flow controlling by default */
	set_mctrl(port, TIOCM_DTR | TIOCM_RTS);

	/* Not throttled */
	spin_lock_irqsave(&priv->rx_lock, flags);
	priv->rx_flags &= ~(THROTTLED | ACTUALLY_THROTTLED);
	spin_unlock_irqrestore(&priv->rx_lock, flags);

	/* Start reading from the device */
	priv->rx_processed = 0;
	usb_fill_bulk_urb(port->read_urb, dev,
		      usb_rcvbulkpipe(dev, port->bulk_in_endpointAddress),
		      port->read_urb->transfer_buffer, port->read_urb->transfer_buffer_length,
		      ftdi_read_bulk_callback, port);
	result = usb_submit_urb(port->read_urb, GFP_KERNEL);
	if (result)
		err("%s - failed submitting read urb, error %d", __FUNCTION__, result);


	return result;
} /* ftdi_open */



/*
 * usbserial:__serial_close  only calls ftdi_close if the point is open
 *
 *   This only gets called when it is the last close
 *
 *
 */

static void ftdi_close (struct usb_serial_port *port, struct file *filp)
{ /* ftdi_close */
	unsigned int c_cflag = port->tty->termios->c_cflag;
	struct ftdi_private *priv = usb_get_serial_port_data(port);
	char buf[1];

	dbg("%s", __FUNCTION__);

	if (c_cflag & HUPCL){
		/* Disable flow control */
		if (usb_control_msg(port->serial->dev,
				    usb_sndctrlpipe(port->serial->dev, 0),
				    FTDI_SIO_SET_FLOW_CTRL_REQUEST,
				    FTDI_SIO_SET_FLOW_CTRL_REQUEST_TYPE,
				    0, priv->interface, buf, 0,
				    WDR_TIMEOUT) < 0) {
			err("error from flowcontrol urb");
		}

		/* drop RTS and DTR */
		clear_mctrl(port, TIOCM_DTR | TIOCM_RTS);
	} /* Note change no line if hupcl is off */

	/* cancel any scheduled reading */
	cancel_delayed_work(&priv->rx_work);
	flush_scheduled_work();

	/* shutdown our bulk read */
	usb_kill_urb(port->read_urb);
} /* ftdi_close */



/* The SIO requires the first byte to have:
 *  B0 1
 *  B1 0
 *  B2..7 length of message excluding byte 0
 *
 * The new devices do not require this byte
 */
static int ftdi_write (struct usb_serial_port *port,
			   const unsigned char *buf, int count)
{ /* ftdi_write */
	struct ftdi_private *priv = usb_get_serial_port_data(port);
	struct urb *urb;
	unsigned char *buffer;
	int data_offset ;       /* will be 1 for the SIO and 0 otherwise */
	int status;
	int transfer_size;
	unsigned long flags;

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

	if (count == 0) {
		dbg("write request of 0 bytes");
		return 0;
	}
	spin_lock_irqsave(&priv->tx_lock, flags);
	if (priv->tx_outstanding_urbs > URB_UPPER_LIMIT) {
		spin_unlock_irqrestore(&priv->tx_lock, flags);
		dbg("%s - write limit hit\n", __FUNCTION__);
		return 0;
	}
	priv->tx_outstanding_urbs++;
	spin_unlock_irqrestore(&priv->tx_lock, flags);

	data_offset = priv->write_offset;
        dbg("data_offset set to %d",data_offset);

	/* Determine total transfer size */
	transfer_size = count;
	if (data_offset > 0) {
		/* Original sio needs control bytes too... */
		transfer_size += (data_offset *
				((count + (PKTSZ - 1 - data_offset)) /
				 (PKTSZ - data_offset)));
	}

	buffer = kmalloc (transfer_size, GFP_ATOMIC);