ftdi_sio.c

usb driver for 2.6.17

	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;

	/* 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_WORK(&priv->rx_work, ftdi_process_read, 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(serial->port[0], priv);

	ftdi_determine_type (serial->port[0]);
	create_sysfs_attrs(serial);

	/* Check for device requiring special set up. */
	quirk = (struct ftdi_sio_quirk *)usb_get_serial_data(serial);
	if (quirk && quirk->setup) {
		quirk->setup(serial);
	}
	
	return (0);
} /* ftdi_sio_attach */


/* 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 usb_serial *serial)
{
	struct ftdi_private *priv;

	dbg("%s",__FUNCTION__);

	priv = usb_get_serial_port_data(serial->port[0]);
	priv->flags |= ASYNC_SPD_CUST;
	priv->custom_divisor = 77;
	priv->force_baud = B38400;
} /* 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 usb_serial *serial)
{
	struct ftdi_private *priv;

	dbg("%s",__FUNCTION__);

	priv = usb_get_serial_port_data(serial->port[0]);
	priv->flags |= ASYNC_SPD_CUST;
	priv->custom_divisor = 240;
	priv->force_baud = B38400;
	priv->force_rtscts = 1;
} /* ftdi_HE_TIRA1_setup */


/* 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)
{ /* ftdi_shutdown */
	
	struct usb_serial_port *port = serial->port[0];
	struct ftdi_private *priv = usb_get_serial_port_data(port);

	dbg("%s", __FUNCTION__);

	remove_sysfs_attrs(serial);
	
	/* 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);
	}
} /* ftdi_shutdown */


static int  ftdi_open (struct usb_serial_port *port, struct file *filp)
{ /* ftdi_open */
	struct termios tmp_termios;
	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__);


	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 */
	ftdi_set_termios(port, &tmp_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 */
	if (port->read_urb)
		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;
	}
	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);
	if (!buffer) {
		err("%s ran out of kernel memory for urb ...", __FUNCTION__);
		return -ENOMEM;
	}

	urb = usb_alloc_urb(0, GFP_ATOMIC);
	if (!urb) {
		err("%s - no more free urbs", __FUNCTION__);
		kfree (buffer);
		return -ENOMEM;
	}

	/* Copy data */
	if (data_offset > 0) {
		/* Original sio requires control byte at start of each packet. */
		int user_pktsz = PKTSZ - data_offset;
		int todo = count;
		unsigned char *first_byte = buffer;
		const unsigned char *current_position = buf;

		while (todo > 0) {
			if (user_pktsz > todo) {
				user_pktsz = todo;
			}
			/* Write the control byte at the front of the packet*/
			*first_byte = 1 | ((user_pktsz) << 2); 
			/* Copy data for packet */
			memcpy (first_byte + data_offset,
				current_position, user_pktsz);
			first_byte += user_pktsz + data_offset;
			current_position += user_pktsz;
			todo -= user_pktsz;
		}
	} else {
		/* No control byte required. */
		/* Copy in the data to send */
		memcpy (buffer, buf, count);
	}

	usb_serial_debug_data(debug, &port->dev, __FUNCTION__, transfer_size, buffer);

	/* fill the buffer and send it */
	usb_fill_bulk_urb(urb, port->serial->dev, 
		      usb_sndbulkpipe(port->serial->dev, port->bulk_out_endpointAddress),
		      buffer, transfer_size,
		      ftdi_write_bulk_callback, port);

	status = usb_submit_urb(urb, GFP_ATOMIC);
	if (status) {
		err("%s - failed submitting write urb, error %d", __FUNCTION__, status);
		count = status;
		kfree (buffer);
	} else {
		spin_lock_irqsave(&priv->tx_lock, flags);
		++priv->tx_outstanding_urbs;
		priv->tx_outstanding_bytes += count;
		spin_unlock_irqrestore(&priv->tx_lock, flags);
	}

	/* we are done with this urb, so let the host driver
	 * really free it when it is finished with it */
	usb_free_urb (urb);

	dbg("%s write returning: %d", __FUNCTION__, count);
	return count;
} /* ftdi_write */


/* This function may get called when the device is closed */

static void ftdi_write_bulk_callback (struct urb *urb, struct pt_regs *regs)
{
	unsigned long flags;
	struct usb_serial_port *port = (struct usb_serial_port *)urb->context;
	struct ftdi_private *priv;
	int data_offset;       /* will be 1 for the SIO and 0 otherwise */
	unsigned long countback;

	/* free up the transfer buffer, as usb_free_urb() does not do this */
	kfree (urb->transfer_buffer);

	dbg("%s - port %d", __FUNCTION__, port->number);
	
	if (urb->status) {
		dbg("nonzero write bulk status received: %d", urb->status);
		return;
	}

	priv = usb_get_serial_port_data(port);
	if (!priv) {
		dbg("%s - bad port private data pointer - exiting", __FUNCTION__);
		return;
	}
	/* account for transferred data */
	countback = urb->actual_length;
	data_offset = priv->write_offset;
	if (data_offset > 0) {
		/* Subtract the control bytes */
		countback -= (data_offset * ((countback + (PKTSZ - 1)) / PKTSZ));
	}
	spin_lock_irqsave(&priv->tx_lock, flags);
	--priv->tx_outstanding_urbs;
	priv->tx_outstanding_bytes -= countback;
	spin_unlock_irqrestore(&priv->tx_lock, flags);

	schedule_work(&port->work);
} /* ftdi_write_bulk_callback */


static int ftdi_write_room( struct usb_serial_port *port )
{
	struct ftdi_private *priv = usb_get_serial_port_data(port);
	int room;
	unsigned long flags;

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

	spin_lock_irqsave(&priv->tx_lock, flags);
	if (priv->tx_outstanding_urbs < URB_UPPER_LIMIT) {
		/*
		 * We really can take anything the user throws at us
		 * but let's pick a nice big number to tell the tty
		 * layer that we have lots of free space
		 */
		room = 2048;
	} else {
		room = 0;
	}
	spin_unlock_irqrestore(&priv->tx_lock, flags);
	return room;
} /* ftdi_write_room */