ftdi_sio.c

linux-2.6.15.6

	priv = usb_get_serial_port_data(port);
	if (!priv) {
		dbg("%s - bad port private data pointer - exiting", __FUNCTION__);
		return;
	}

	urb = port->read_urb;
	if (!urb) {
		dbg("%s - bad read_urb pointer - exiting", __FUNCTION__);
		return;
	}

	data = urb->transfer_buffer;

	if (priv->rx_processed) {
		dbg("%s - already processed: %d bytes, %d remain", __FUNCTION__,
				priv->rx_processed,
				urb->actual_length - priv->rx_processed);
	} else {
		/* The first two bytes of every read packet are status */
		if (urb->actual_length > 2) {
			usb_serial_debug_data(debug, &port->dev, __FUNCTION__, urb->actual_length, data);
		} else {
			dbg("Status only: %03oo %03oo",data[0],data[1]);
		}
	}


	/* TO DO -- check for hung up line and handle appropriately: */
	/*   send hangup  */
	/* See acm.c - you do a tty_hangup  - eg tty_hangup(tty) */
	/* if CD is dropped and the line is not CLOCAL then we should hangup */

	need_flip = 0;
	for (packet_offset = priv->rx_processed; packet_offset < urb->actual_length; packet_offset += PKTSZ) {
		int length;

		/* Compare new line status to the old one, signal if different */
		/* N.B. packet may be processed more than once, but differences
		 * are only processed once.  */
		if (priv != NULL) {
			char new_status = data[packet_offset+0] & FTDI_STATUS_B0_MASK;
			if (new_status != priv->prev_status) {
				priv->diff_status |= new_status ^ priv->prev_status;
				wake_up_interruptible(&priv->delta_msr_wait);
				priv->prev_status = new_status;
			}
		}

		length = min(PKTSZ, urb->actual_length-packet_offset)-2;
		if (length < 0) {
			err("%s - bad packet length: %d", __FUNCTION__, length+2);
			length = 0;
		}

		/* have to make sure we don't overflow the buffer
		   with tty_insert_flip_char's */
		if (tty->flip.count+length > TTY_FLIPBUF_SIZE) {
			tty_flip_buffer_push(tty);
			need_flip = 0;

			if (tty->flip.count != 0) {
				/* flip didn't work, this happens when ftdi_process_read() is
				 * called from ftdi_unthrottle, because TTY_DONT_FLIP is set */
				dbg("%s - flip buffer push failed", __FUNCTION__);
				break;
			}
		}
		if (priv->rx_flags & THROTTLED) {
			dbg("%s - throttled", __FUNCTION__);
			break;
		}
		if (tty->ldisc.receive_room(tty)-tty->flip.count < length) {
			/* break out & wait for throttling/unthrottling to happen */
			dbg("%s - receive room low", __FUNCTION__);
			break;
		}

		/* Handle errors and break */
		error_flag = TTY_NORMAL;
		/* Although the device uses a bitmask and hence can have multiple */
		/* errors on a packet - the order here sets the priority the */
		/* error is returned to the tty layer  */

		if ( data[packet_offset+1] & FTDI_RS_OE ) {
			error_flag = TTY_OVERRUN;
			dbg("OVERRRUN error");
		}
		if ( data[packet_offset+1] & FTDI_RS_BI ) {
			error_flag = TTY_BREAK;
			dbg("BREAK received");
		}
		if ( data[packet_offset+1] & FTDI_RS_PE ) {
			error_flag = TTY_PARITY;
			dbg("PARITY error");
		}
		if ( data[packet_offset+1] & FTDI_RS_FE ) {
			error_flag = TTY_FRAME;
			dbg("FRAMING error");
		}
		if (length > 0) {
			for (i = 2; i < length+2; i++) {
				/* Note that the error flag is duplicated for 
				   every character received since we don't know
				   which character it applied to */
				tty_insert_flip_char(tty, data[packet_offset+i], error_flag);
			}
			need_flip = 1;
		}

#ifdef NOT_CORRECT_BUT_KEEPING_IT_FOR_NOW
		/* if a parity error is detected you get status packets forever
		   until a character is sent without a parity error.
		   This doesn't work well since the application receives a never
		   ending stream of bad data - even though new data hasn't been sent.
		   Therefore I (bill) have taken this out.
		   However - this might make sense for framing errors and so on 
		   so I am leaving the code in for now.
		*/
		else {
			if (error_flag != TTY_NORMAL){
				dbg("error_flag is not normal");
				/* In this case it is just status - if that is an error send a bad character */
				if(tty->flip.count >= TTY_FLIPBUF_SIZE) {
					tty_flip_buffer_push(tty);
				}
				tty_insert_flip_char(tty, 0xff, error_flag);
				need_flip = 1;
			}
		}
#endif
	} /* "for(packet_offset=0..." */

	/* Low latency */
	if (need_flip) {
		tty_flip_buffer_push(tty);
	}

	if (packet_offset < urb->actual_length) {
		/* not completely processed - record progress */
		priv->rx_processed = packet_offset;
		dbg("%s - incomplete, %d bytes processed, %d remain",
				__FUNCTION__, packet_offset,
				urb->actual_length - packet_offset);
		/* check if we were throttled while processing */
		spin_lock_irqsave(&priv->rx_lock, flags);
		if (priv->rx_flags & THROTTLED) {
			priv->rx_flags |= ACTUALLY_THROTTLED;
			spin_unlock_irqrestore(&priv->rx_lock, flags);
			dbg("%s - deferring remainder until unthrottled",
					__FUNCTION__);
			return;
		}
		spin_unlock_irqrestore(&priv->rx_lock, flags);
		/* if the port is closed stop trying to read */
		if (port->open_count > 0){
			/* delay processing of remainder */
			schedule_delayed_work(&priv->rx_work, 1);
		} else {
			dbg("%s - port is closed", __FUNCTION__);
		}
		return;
	}

	/* urb is completely processed */
	priv->rx_processed = 0;

	/* if the port is closed stop trying to read */
	if (port->open_count > 0){
		/* Continue trying to always read  */
		usb_fill_bulk_urb(port->read_urb, port->serial->dev, 
			      usb_rcvbulkpipe(port->serial->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_ATOMIC);
		if (result)
			err("%s - failed resubmitting read urb, error %d", __FUNCTION__, result);
	}

	return;
} /* ftdi_process_read */


static void ftdi_break_ctl( struct usb_serial_port *port, int break_state )
{
	struct ftdi_private *priv = usb_get_serial_port_data(port);
	__u16 urb_value = 0; 
	char buf[1];
	
	/* break_state = -1 to turn on break, and 0 to turn off break */
	/* see drivers/char/tty_io.c to see it used */
	/* last_set_data_urb_value NEVER has the break bit set in it */

	if (break_state) {
		urb_value = priv->last_set_data_urb_value | FTDI_SIO_SET_BREAK;
	} else {
		urb_value = priv->last_set_data_urb_value; 
	}

	
	if (usb_control_msg(port->serial->dev, usb_sndctrlpipe(port->serial->dev, 0),
			    FTDI_SIO_SET_DATA_REQUEST, 
			    FTDI_SIO_SET_DATA_REQUEST_TYPE,
			    urb_value , priv->interface,
			    buf, 0, WDR_TIMEOUT) < 0) {
		err("%s FAILED to enable/disable break state (state was %d)", __FUNCTION__,break_state);
	}	   

	dbg("%s break state is %d - urb is %d", __FUNCTION__,break_state, urb_value);
	
}


/* old_termios contains the original termios settings and tty->termios contains
 * the new setting to be used
 * WARNING: set_termios calls this with old_termios in kernel space
 */

static void ftdi_set_termios (struct usb_serial_port *port, struct termios *old_termios)
{ /* ftdi_termios */
	struct usb_device *dev = port->serial->dev;
	unsigned int cflag = port->tty->termios->c_cflag;
	struct ftdi_private *priv = usb_get_serial_port_data(port);
	__u16 urb_value; /* will hold the new flags */
	char buf[1]; /* Perhaps I should dynamically alloc this? */
	
	// Added for xon/xoff support
	unsigned int iflag = port->tty->termios->c_iflag;
	unsigned char vstop;
	unsigned char vstart;
	
	dbg("%s", __FUNCTION__);

	/* Force baud rate if this device requires it, unless it is set to B0. */
	if (priv->force_baud && ((port->tty->termios->c_cflag & CBAUD) != B0)) {
		dbg("%s: forcing baud rate for this device", __FUNCTION__);
		port->tty->termios->c_cflag &= ~CBAUD;
		port->tty->termios->c_cflag |= priv->force_baud;
	}

	/* Force RTS-CTS if this device requires it. */
	if (priv->force_rtscts) {
		dbg("%s: forcing rtscts for this device", __FUNCTION__);
		port->tty->termios->c_cflag |= CRTSCTS;
	}

	cflag = port->tty->termios->c_cflag;

	/* FIXME -For this cut I don't care if the line is really changing or 
	   not  - so just do the change regardless  - should be able to 
	   compare old_termios and tty->termios */
	/* NOTE These routines can get interrupted by 
	   ftdi_sio_read_bulk_callback  - need to examine what this 
           means - don't see any problems yet */
	
	/* Set number of data bits, parity, stop bits */
	
	urb_value = 0;
	urb_value |= (cflag & CSTOPB ? FTDI_SIO_SET_DATA_STOP_BITS_2 :
		      FTDI_SIO_SET_DATA_STOP_BITS_1);
	urb_value |= (cflag & PARENB ? 
		      (cflag & PARODD ? FTDI_SIO_SET_DATA_PARITY_ODD : 
		       FTDI_SIO_SET_DATA_PARITY_EVEN) :
		      FTDI_SIO_SET_DATA_PARITY_NONE);
	if (cflag & CSIZE) {
		switch (cflag & CSIZE) {
		case CS5: urb_value |= 5; dbg("Setting CS5"); break;
		case CS6: urb_value |= 6; dbg("Setting CS6"); break;
		case CS7: urb_value |= 7; dbg("Setting CS7"); break;
		case CS8: urb_value |= 8; dbg("Setting CS8"); break;
		default:
			err("CSIZE was set but not CS5-CS8");
		}
	}

	/* This is needed by the break command since it uses the same command - but is
	 *  or'ed with this value  */
	priv->last_set_data_urb_value = urb_value;
	
	if (usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
			    FTDI_SIO_SET_DATA_REQUEST, 
			    FTDI_SIO_SET_DATA_REQUEST_TYPE,
			    urb_value , priv->interface,
			    buf, 0, WDR_SHORT_TIMEOUT) < 0) {
		err("%s FAILED to set databits/stopbits/parity", __FUNCTION__);
	}	   

	/* Now do the baudrate */
	if ((cflag & CBAUD) == B0 ) {
		/* Disable flow control */
		if (usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
				    FTDI_SIO_SET_FLOW_CTRL_REQUEST, 
				    FTDI_SIO_SET_FLOW_CTRL_REQUEST_TYPE,
				    0, priv->interface, 
				    buf, 0, WDR_TIMEOUT) < 0) {
			err("%s error from disable flowcontrol urb", __FUNCTION__);
		}	    
		/* Drop RTS and DTR */
		clear_mctrl(port, TIOCM_DTR | TIOCM_RTS);
	} else {
		/* set the baudrate determined before */
		if (change_speed(port)) {
			err("%s urb failed to set baudrate", __FUNCTION__);
		}
		/* Ensure RTS and DTR are raised when baudrate changed from 0 */
		if ((old_termios->c_cflag & CBAUD) == B0) {
			set_mctrl(port, TIOCM_DTR | TIOCM_RTS);
		}
	}

	/* Set flow control */
	/* Note device also supports DTR/CD (ugh) and Xon/Xoff in hardware */
	if (cflag & CRTSCTS) {
		dbg("%s Setting to CRTSCTS flow control", __FUNCTION__);
		if (usb_control_msg(dev, 
				    usb_sndctrlpipe(dev, 0),
				    FTDI_SIO_SET_FLOW_CTRL_REQUEST, 
				    FTDI_SIO_SET_FLOW_CTRL_REQUEST_TYPE,
				    0 , (FTDI_SIO_RTS_CTS_HS | priv->interface),
				    buf, 0, WDR_TIMEOUT) < 0) {
			err("urb failed to set to rts/cts flow control");
		}		
		
	} else { 
		/*
		 * Xon/Xoff code
		 *
		 * Check the IXOFF status in the iflag component of the termios structure
		 * if IXOFF is not set, the pre-xon/xoff code is executed.
		*/
		if (iflag & IXOFF) {
			dbg("%s  request to enable xonxoff iflag=%04x",__FUNCTION__,iflag);
			// Try to enable the XON/XOFF on the ftdi_sio
			// Set the vstart and vstop -- could have been done up above where
			// a lot of other dereferencing is done but that would be very
			// inefficient as vstart and vstop are not always needed
			vstart=port->tty->termios->c_cc[VSTART];
			vstop=port->tty->termios->c_cc[VSTOP];
			urb_value=(vstop << 8) | (vstart);

			if (usb_control_msg(dev,
					    usb_sndctrlpipe(dev, 0),
					    FTDI_SIO_SET_FLOW_CTRL_REQUEST,
					    FTDI_SIO_SET_FLOW_CTRL_REQUEST_TYPE,
					    urb_value , (FTDI_SIO_XON_XOFF_HS
							 | priv->interface),
					    buf, 0, WDR_TIMEOUT) < 0) {
				err("urb failed to set to xon/xoff flow control");
			}
		} else {
			/* else clause to only run if cfag ! CRTSCTS and iflag ! XOFF */
			/* CHECKME Assuming XON/XOFF handled by tty stack - not by device */
			dbg("%s Turning off hardware flow control", __FUNCTION__);
			if (usb_control_msg(dev, 
					    usb_sndctrlpipe(dev, 0),
					    FTDI_SIO_SET_FLOW_CTRL_REQUEST, 
					    FTDI_SIO_SET_FLOW_CTRL_REQUEST_TYPE,
					    0, priv->interface, 
					    buf, 0, WDR_TIMEOUT) < 0) {
				err("urb failed to clear flow control");
			}				
		}
		
	}
	return;
} /* ftdi_termios */


static int ftdi_tiocmget (struct usb_serial_port *port, struct file *file)
{
	struct ftdi_private *priv = usb_get_serial_port_data(port);
	unsigned char buf[2];
	int ret;

	dbg("%s TIOCMGET", __FUNCTION__);
	switch (priv->chip_type) {
	case SIO:
		/* Request the status from the device */
		if ((ret = usb_control_msg(port->serial->dev, 
					   usb_rcvctrlpipe(port->serial->dev, 0),
					   FTDI_SIO_GET_MODEM_STATUS_REQUEST, 
					   FTDI_SIO_GET_MODEM_STATUS_REQUEST_TYPE,