ftdi_sio.c

讲述linux的初始化过程

		count += data_offset;
		count = (count > port->bulk_out_size) ? port->bulk_out_size : count;
		if (count == 0) {
			return 0;
		}

		/* Copy in the data to send */
		if (from_user) {
			copy_from_user(port->write_urb->transfer_buffer + data_offset , 
				       buf, count - data_offset );
		}
		else {
			memcpy(port->write_urb->transfer_buffer + data_offset,
			       buf, count - data_offset );
		}  

		first_byte = port->write_urb->transfer_buffer;
		if (data_offset > 0){
			/* Write the control byte at the front of the packet*/
			*first_byte = 1 | ((count-data_offset) << 2) ; 
		}

		dbg(__FUNCTION__ " Bytes: %d, First Byte: 0o%03o",count, first_byte[0]);
		usb_serial_debug_data (__FILE__, __FUNCTION__, count, first_byte);
		
		/* send the data out the bulk port */
		FILL_BULK_URB(port->write_urb, serial->dev, 
			      usb_sndbulkpipe(serial->dev, port->bulk_out_endpointAddress),
			      port->write_urb->transfer_buffer, count,
			      ftdi_sio_write_bulk_callback, port);
		
		result = usb_submit_urb(port->write_urb);
		if (result) {
			err(__FUNCTION__ " - failed submitting write urb, error %d", result);
			return 0;
		}

		dbg(__FUNCTION__ " write returning: %d", count - data_offset);
		return (count - data_offset);
	}
	
	/* no bulk out, so return 0 bytes written */
	return 0;
 err: /* error exit */
	return(rc);
} /* ftdi_sio_write */

static void ftdi_sio_write_bulk_callback (struct urb *urb)
{
	struct usb_serial_port *port = (struct usb_serial_port *)urb->context;
	struct usb_serial *serial;
       	struct tty_struct *tty = port->tty;

	dbg("ftdi_sio_write_bulk_callback");

	if (port_paranoia_check (port, "ftdi_sio_write_bulk_callback")) {
		return;
	}

	serial = port->serial;
	if (serial_paranoia_check (serial, "ftdi_sio_write_bulk_callback")) {
		return;
	}
	
	if (urb->status) {
		dbg("nonzero write bulk status received: %d", urb->status);
		return;
	}

	wake_up_interruptible(&port->write_wait);
	if ((tty->flags & (1 << TTY_DO_WRITE_WAKEUP)) && tty->ldisc.write_wakeup)
		(tty->ldisc.write_wakeup)(tty);

	wake_up_interruptible(&tty->write_wait);
	
	return;
} /* ftdi_sio_write_bulk_callback */

static void ftdi_sio_read_bulk_callback (struct urb *urb)
{ /* ftdi_sio_serial_buld_callback */
	struct usb_serial_port *port = (struct usb_serial_port *)urb->context;
	struct ftdi_private *priv = (struct ftdi_private *)port->private;
	struct usb_serial *serial;
       	struct tty_struct *tty = port->tty ;
       	unsigned char *data = urb->transfer_buffer;

	const int data_offset = 2;
	int i;
	int result;

	dbg(__FUNCTION__);

	if (port_paranoia_check (port, "ftdi_sio_read_bulk_callback")) {
		return;
	}

	serial = port->serial;
	if (serial_paranoia_check (serial, "ftdi_sio_read_bulk_callback")) {
		return;
	}

	if (urb->status) {
		/* This will happen at close every time so it is a dbg not an err */
		dbg("nonzero read bulk status received: %d", urb->status);
		return;
	}

	if (urb->actual_length > 2) {
		usb_serial_debug_data (__FILE__, __FUNCTION__, urb->actual_length, data);
	} else {
                dbg("Just status");
        }

	priv->last_status_byte = data[0]; /* this has modem control lines */

	/* 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 */


	if (urb->actual_length > data_offset) {
		for (i = data_offset ; i < urb->actual_length ; ++i) {
			tty_insert_flip_char(tty, data[i], 0);
	  	}
	  	tty_flip_buffer_push(tty);
	}

	/* Continue trying to always read  */
	FILL_BULK_URB(urb, serial->dev, 
		      usb_rcvbulkpipe(serial->dev, port->bulk_in_endpointAddress),
		      urb->transfer_buffer, urb->transfer_buffer_length,
		      ftdi_sio_read_bulk_callback, port);

	result = usb_submit_urb(urb);
	if (result)
		err(__FUNCTION__ " - failed resubmitting read urb, error %d", result);

	return;
} /* ftdi_sio_serial_read_bulk_callback */


__u16 translate_baudrate_to_ftdi(unsigned int cflag, ftdi_type_t ftdi_type) 
{ /* translate_baudrate_to_ftdi */
	
	__u16 urb_value = ftdi_sio_b9600;

	if (ftdi_type == sio){
		switch(cflag & CBAUD){
		case B0: break; /* ignored by this */
		case B300: urb_value = ftdi_sio_b300; dbg("Set to 300"); break;
		case B600: urb_value = ftdi_sio_b600; dbg("Set to 600") ; break;
		case B1200: urb_value = ftdi_sio_b1200; dbg("Set to 1200") ; break;
		case B2400: urb_value = ftdi_sio_b2400; dbg("Set to 2400") ; break;
		case B4800: urb_value = ftdi_sio_b4800; dbg("Set to 4800") ; break;
		case B9600: urb_value = ftdi_sio_b9600; dbg("Set to 9600") ; break;
		case B19200: urb_value = ftdi_sio_b19200; dbg("Set to 19200") ; break;
		case B38400: urb_value = ftdi_sio_b38400; dbg("Set to 38400") ; break;
		case B57600: urb_value = ftdi_sio_b57600; dbg("Set to 57600") ; break;
		case B115200: urb_value = ftdi_sio_b115200; dbg("Set to 115200") ; break;
		default: dbg(__FUNCTION__ " FTDI_SIO does not support the baudrate (%d) requested",
			     (cflag & CBAUD)); 
		   break;
		}
	} else { /* it is 8U232AM */
		switch(cflag & CBAUD){
		case B0: break; /* ignored by this */
		case B300: urb_value = ftdi_8U232AM_48MHz_b300; dbg("Set to 300"); break;
		case B600: urb_value = ftdi_8U232AM_48MHz_b600; dbg("Set to 600") ; break;
		case B1200: urb_value = ftdi_8U232AM_48MHz_b1200; dbg("Set to 1200") ; break;
		case B2400: urb_value = ftdi_8U232AM_48MHz_b2400; dbg("Set to 2400") ; break;
		case B4800: urb_value = ftdi_8U232AM_48MHz_b4800; dbg("Set to 4800") ; break;
		case B9600: urb_value = ftdi_8U232AM_48MHz_b9600; dbg("Set to 9600") ; break;
		case B19200: urb_value = ftdi_8U232AM_48MHz_b19200; dbg("Set to 19200") ; break;
		case B38400: urb_value = ftdi_8U232AM_48MHz_b38400; dbg("Set to 38400") ; break;
		case B57600: urb_value = ftdi_8U232AM_48MHz_b57600; dbg("Set to 57600") ; break;
		case B115200: urb_value = ftdi_8U232AM_48MHz_b115200; dbg("Set to 115200") ; break;
		case B230400: urb_value = ftdi_8U232AM_48MHz_b230400; dbg("Set to 230400") ; break;
		case B460800: urb_value = ftdi_8U232AM_48MHz_b460800; dbg("Set to 460800") ; break;
		case B921600: urb_value = ftdi_8U232AM_48MHz_b921600; dbg("Set to 921600") ; break;
		default: dbg(__FUNCTION__ " The baudrate (%d) requested is not implemented",
			     (cflag & CBAUD)); 
		   break;
		}
	}
	return(urb_value);
}

/* As I understand this - 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_sio_set_termios (struct usb_serial_port *port, struct termios *old_termios)
{ /* ftdi_sio_set_termios */
	struct usb_serial *serial = port->serial;
	unsigned int cflag = port->tty->termios->c_cflag;
	struct ftdi_private *priv = (struct ftdi_private *)port->private;	
	__u16 urb_value; /* will hold the new flags */
	char buf[1]; /* Perhaps I should dynamically alloc this? */
	
	
	dbg(__FUNCTION__);


	/* 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");
		}
	}
	if (usb_control_msg(serial->dev, usb_sndctrlpipe(serial->dev, 0),
			    FTDI_SIO_SET_DATA_REQUEST, 
			    FTDI_SIO_SET_DATA_REQUEST_TYPE,
			    urb_value , 0,
			    buf, 0, 100) < 0) {
		err(__FUNCTION__ " FAILED to set databits/stopbits/parity");
	}	   

	/* Now do the baudrate */
	urb_value = translate_baudrate_to_ftdi((cflag & CBAUD), priv->ftdi_type);
	
	if ((cflag & CBAUD) == B0 ) {
		/* Disable flow control */
		if (usb_control_msg(serial->dev, usb_sndctrlpipe(serial->dev, 0),
				    FTDI_SIO_SET_FLOW_CTRL_REQUEST, 
				    FTDI_SIO_SET_FLOW_CTRL_REQUEST_TYPE,
				    0, 0, 
				    buf, 0, WDR_TIMEOUT) < 0) {
			err(__FUNCTION__ " error from disable flowcontrol urb");
		}	    
		/* Drop RTS and DTR */
		if (set_dtr(serial->dev, usb_sndctrlpipe(serial->dev, 0),LOW) < 0){
			err(__FUNCTION__ " Error from DTR LOW urb");
		}
		if (set_rts(serial->dev, usb_sndctrlpipe(serial->dev, 0),LOW) < 0){
			err(__FUNCTION__ " Error from RTS LOW urb");
		}	
		
	} else {
		/* set the baudrate determined before */
		if (usb_control_msg(serial->dev, 
				    usb_sndctrlpipe(serial->dev, 0),
				    FTDI_SIO_SET_BAUDRATE_REQUEST, 
				    FTDI_SIO_SET_BAUDRATE_REQUEST_TYPE,
				    urb_value, 0, 
				    buf, 0, 100) < 0) {
			err(__FUNCTION__ " urb failed to set baurdrate");
		}
	}
	/* Set flow control */
	/* Note device also supports DTR/CD (ugh) and Xon/Xoff in hardware */
	if (cflag & CRTSCTS) {
		dbg(__FUNCTION__ " Setting to CRTSCTS flow control");
		if (usb_control_msg(serial->dev, 
				    usb_sndctrlpipe(serial->dev, 0),
				    FTDI_SIO_SET_FLOW_CTRL_REQUEST, 
				    FTDI_SIO_SET_FLOW_CTRL_REQUEST_TYPE,
				    0 , FTDI_SIO_RTS_CTS_HS,
				    buf, 0, WDR_TIMEOUT) < 0) {
			err("urb failed to set to rts/cts flow control");
		}		
		
	} else { 
		/* CHECKME Assuming XON/XOFF handled by tty stack - not by device */
		dbg(__FUNCTION__ " Turning off hardware flow control");
		if (usb_control_msg(serial->dev, 
				    usb_sndctrlpipe(serial->dev, 0),
				    FTDI_SIO_SET_FLOW_CTRL_REQUEST, 
				    FTDI_SIO_SET_FLOW_CTRL_REQUEST_TYPE,
				    0, 0, 
				    buf, 0, WDR_TIMEOUT) < 0) {
			err("urb failed to clear flow control");
		}				
		
	}
	return;
} /* ftdi_sio_set_termios */

static int ftdi_sio_ioctl (struct usb_serial_port *port, struct file * file, unsigned int cmd, unsigned long arg)
{
	struct usb_serial *serial = port->serial;
	struct ftdi_private *priv = (struct ftdi_private *)port->private;
	__u16 urb_value=0; /* Will hold the new flags */
	char buf[1];
	int  ret, mask;
	
	dbg(__FUNCTION__ " cmd 0x%04x", cmd);

	/* Based on code from acm.c and others */
	switch (cmd) {

	case TIOCMGET:
		dbg(__FUNCTION__ " TIOCMGET");
		/* The MODEM_STATUS_REQUEST works for the sio but not the 232 */
		if (priv->ftdi_type == sio){
			/* TO DECIDE - use the 40ms status packets or not? */
			/*   PRO: No need to send urb */
			/*   CON: Could be 40ms out of date */

			/* Request the status from the device */
			if ((ret = usb_control_msg(serial->dev, 
						   usb_rcvctrlpipe(serial->dev, 0),
						   FTDI_SIO_GET_MODEM_STATUS_REQUEST, 
						   FTDI_SIO_GET_MODEM_STATUS_REQUEST_TYPE,
						   0, 0, 
						   buf, 1, WDR_TIMEOUT)) < 0 ) {
				err(__FUNCTION__ " Could not get modem status of device - err: %d",
				    ret);
				return(ret);
			}
		} else {
			/* This gets updated every 40ms - so just copy it in */
			buf[0] = priv->last_status_byte;
		}

		return put_user((buf[0] & FTDI_SIO_DSR_MASK ? TIOCM_DSR : 0) |
				(buf[0] & FTDI_SIO_CTS_MASK ? TIOCM_CTS : 0) |
				(buf[0]  & FTDI_SIO_RI_MASK  ? TIOCM_RI  : 0) |
				(buf[0]  & FTDI_SIO_RLSD_MASK ? TIOCM_CD  : 0),
				(unsigned long *) arg);
		break;

	case TIOCMSET: /* Turns on and off the lines as specified by the mask */
		dbg(__FUNCTION__ " TIOCMSET");
		if ((ret = get_user(mask, (unsigned long *) arg))) return ret;
		urb_value = ((mask & TIOCM_DTR) ? HIGH : LOW);
		if (set_dtr(serial->dev, usb_sndctrlpipe(serial->dev, 0),urb_value) < 0){
			err("Error from DTR set urb (TIOCMSET)");
		}
		urb_value = ((mask & TIOCM_RTS) ? HIGH : LOW);
		if (set_rts(serial->dev, usb_sndctrlpipe(serial->dev, 0),urb_value) < 0){
			err("Error from RTS set urb (TIOCMSET)");
		}	
		break;
					
	case TIOCMBIS: /* turns on (Sets) the lines as specified by the mask */
		dbg(__FUNCTION__ " TIOCMBIS");
 	        if ((ret = get_user(mask, (unsigned long *) arg))) return ret;
  	        if (mask & TIOCM_DTR){
			if ((ret = set_dtr(serial->dev, 
					   usb_sndctrlpipe(serial->dev, 0),
					   HIGH)) < 0) {
				err("Urb to set DTR failed");
				return(ret);
			}
		}
		if (mask & TIOCM_RTS) {
			if ((ret = set_rts(serial->dev, 
					   usb_sndctrlpipe(serial->dev, 0),
					   HIGH)) < 0){
				err("Urb to set RTS failed");
				return(ret);
			}
		}
					break;

	case TIOCMBIC: /* turns off (Clears) the lines as specified by the mask */
		dbg(__FUNCTION__ " TIOCMBIC");
 	        if ((ret = get_user(mask, (unsigned long *) arg))) return ret;
  	        if (mask & TIOCM_DTR){
			if ((ret = set_dtr(serial->dev, 
					   usb_sndctrlpipe(serial->dev, 0),
					   LOW)) < 0){
				err("Urb to unset DTR failed");
				return(ret);
			}
		}	
		if (mask & TIOCM_RTS) {
			if ((ret = set_rts(serial->dev, 
					   usb_sndctrlpipe(serial->dev, 0),
					   LOW)) < 0){
				err("Urb to unset RTS failed");
				return(ret);
			}
		}
		break;

		/*
		 * I had originally implemented TCSET{A,S}{,F,W} and
		 * TCGET{A,S} here separately, however when testing I
		 * found that the higher layers actually do the termios
		 * conversions themselves and pass the call onto
		 * ftdi_sio_set_termios. 
		 *
		 */

	default:
	  /* This is not an error - turns out the higher layers will do 
	   *  some ioctls itself (see comment above)
 	   */
		dbg(__FUNCTION__ " arg not supported - it was 0x%04x",cmd);
		return(-ENOIOCTLCMD);
		break;
	}
	return 0;
} /* ftdi_sio_ioctl */


static int __init ftdi_sio_init (void)
{
	dbg(__FUNCTION__);
	usb_serial_register (&ftdi_sio_device);
	usb_serial_register (&ftdi_8U232AM_device);
	return 0;
}


static void __exit ftdi_sio_exit (void)
{
	dbg(__FUNCTION__);
	usb_serial_deregister (&ftdi_sio_device);
	usb_serial_deregister (&ftdi_8U232AM_device);
}


module_init(ftdi_sio_init);
module_exit(ftdi_sio_exit);

MODULE_AUTHOR("Greg Kroah-Hartman <[e-mail]>, Bill Ryder <[e-mail]>");
MODULE_DESCRIPTION("USB FTDI RS232 converters driver");