ftdi_sio.c

ep9315平台下USB驱动的源码

	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(serial->dev, usb_sndctrlpipe(serial->dev, 0),
			FTDI_SIO_RESET_REQUEST, FTDI_SIO_RESET_REQUEST_TYPE, 
			FTDI_SIO_RESET_SIO, 
			0, 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 */
	if (set_dtr(port, HIGH) < 0) {
		err("%s Error from DTR HIGH urb", __FUNCTION__);
	}
	if (set_rts(port, HIGH) < 0){
		err("%s Error from RTS HIGH urb", __FUNCTION__);
	}

	/* Make sure write_urb is initialised since a write_pool is used now */
	port->write_urb = NULL; /* prevents usbserial.c from trying something silly */


	/* Start reading from the device */
	FILL_BULK_URB(port->read_urb, serial->dev, 
		      usb_rcvbulkpipe(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);
	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 */
	struct usb_serial *serial;
	unsigned int c_cflag = port->tty->termios->c_cflag;
	char buf[1];

	dbg("%s", __FUNCTION__);

	serial = get_usb_serial ( port, __FUNCTION__);
	if (!serial)
		return;

	if (serial->dev) {
		if (c_cflag & HUPCL){
			/* 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("error from flowcontrol urb");
			}	    

			/* drop DTR */
			if (set_dtr(port, LOW) < 0){
				err("Error from DTR LOW urb");
			}
			/* drop RTS */
			if (set_rts(port, LOW) < 0) {
				err("Error from RTS LOW urb");
			}	
			/* shutdown our bulk read */
			if (port->read_urb) {
				usb_unlink_urb (port->read_urb);	
			}
			/* unlink the running write urbs */
			

		} /* Note change no line is hupcl is off */
	} /* if (serial->dev) */


} /* 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, int from_user,
			   const unsigned char *buf, int count)
{ /* ftdi_write */
	struct usb_serial *serial = get_usb_serial ( port, __FUNCTION__);
	struct ftdi_private *priv = (struct ftdi_private *)port->private;
	unsigned char *first_byte;
	int data_offset ;       /* will be 1 for the SIO and 0 otherwise */
	int result;
	int user_bytes_sent = 0 ;   /* amount of user data sent */

	/* Variables for urb pool management */
	unsigned char *current_position = (unsigned char *)buf;
	int i; 
	struct urb *urb; /* pointer to urb from urb pool */
	unsigned long flags;
	/* end of urb pool management */
	
	
	dbg("%s port %d, %d bytes", __FUNCTION__, port->number, count);

	if (count == 0) {
		err("write request of 0 bytes");
		goto exit;
	}
	
	data_offset = priv->write_offset;
        dbg("data_offset set to %d",data_offset);

	while (count > 0) {
		/* urb_byte_count = user_byte_count + data_offset */
		int urb_byte_count;  /* Number of bytes of URB data   */
		int user_byte_count; /* Number of bytes of user data */

		/* Find a free urb in the list */
		urb = NULL;

		spin_lock_irqsave (&(priv->write_urb_pool_lock), flags) ; 

		for (i = 0 ; i < NUM_URBS; i++) {
			if (priv->write_urb_pool[i] -> status != -EINPROGRESS) {
			  urb = priv->write_urb_pool[i];
			  /* Must make sure another device doesn't grab this */
			  /* BUT unfortunately the uhci stack errors if it sees this */
			  /* so have to increase the size of the spin_lock */
			  /* urb->status = -EINPROGRESS; */
				break;
			}
		}


		if (urb == NULL) {
		        spin_unlock_irqrestore (&priv->write_urb_pool_lock, flags);
			dbg("%s - no more free urbs", __FUNCTION__);
			goto exit;
		}

		/* Allocate memory for the urb if necessary */
		if (urb->transfer_buffer == NULL) {
			urb->transfer_buffer = kmalloc (URB_TRANSFER_BUFFER_SIZE, GFP_KERNEL);
			if (urb->transfer_buffer == NULL) {
				spin_unlock_irqrestore (&priv->write_urb_pool_lock, flags);
				err("%s ran out of kernel memory for urb ...", __FUNCTION__);
				goto exit;
			}
		}
		
		/* The original sio needs the first byte to contain the bytecount 
		 * so the urb may be one byte bigger than the user data 
		 */
		urb_byte_count = min (count + data_offset, URB_TRANSFER_BUFFER_SIZE);
		user_byte_count = urb_byte_count - data_offset; 

		/* Copy in the data to send */
		if (from_user) {
			if (copy_from_user(urb->transfer_buffer + data_offset,
					   current_position, user_byte_count )){
				spin_unlock_irqrestore (&priv->write_urb_pool_lock, flags);
				return -EFAULT;
			}
		} else {
			memcpy(urb->transfer_buffer + data_offset,
			       current_position, user_byte_count );
		}  

		first_byte = urb->transfer_buffer;
		if (data_offset > 0){
			/* Write the control byte at the front of the packet*/
			*first_byte = 1 | ((user_byte_count) << 2) ; 
			dbg("%s Bytes: %d, First Byte: 0x%02x", __FUNCTION__,count, first_byte[0]);
		}
		
		usb_serial_debug_data (__FILE__, __FUNCTION__, urb_byte_count, first_byte);
		
		/* fill the buffer and send it */
		FILL_BULK_URB(urb, serial->dev, 
			      usb_sndbulkpipe(serial->dev, port->bulk_out_endpointAddress),
			      urb->transfer_buffer, urb_byte_count,
			      ftdi_write_bulk_callback, port);
		urb->transfer_flags |= USB_QUEUE_BULK;
		
		result = usb_submit_urb(urb);
		if (result) {
			spin_unlock_irqrestore (&priv->write_urb_pool_lock, flags);
			err("%s - failed submitting write urb, error %d", __FUNCTION__, result);
			user_bytes_sent = result;
			goto exit;
		}
		spin_unlock_irqrestore (&priv->write_urb_pool_lock, flags);

		/* house keeping */
		current_position += user_byte_count;
		user_bytes_sent += user_byte_count;
		count -= user_byte_count;
		
	} /* while  count > 0 */

 exit:

	dbg("%s write returning: %d", __FUNCTION__, user_bytes_sent);
	return user_bytes_sent;

} /* ftdi_write */


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

static void ftdi_write_bulk_callback (struct urb *urb)
{
	struct usb_serial_port *port = (struct usb_serial_port *)urb->context;
	struct usb_serial *serial = get_usb_serial (port, __FUNCTION__);

	dbg("%s", __FUNCTION__);

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

	if (!serial) {
		dbg("%s - bad serial pointer, exiting", __FUNCTION__);
		return;
	}

	/* Have to check for validity of queueing up the tasks */
	dbg("%s - port->open_count = %d", __FUNCTION__, port->open_count);

 	if (port->open_count > 0){
		queue_task(&port->tqueue, &tq_immediate);
		mark_bh(IMMEDIATE_BH);
	} 

	return;
} /* ftdi_write_bulk_callback */


static int ftdi_write_room( struct usb_serial_port *port )
{
	struct ftdi_private *priv = (struct ftdi_private *)port->private;
	int room = 0;
	int i;
	unsigned long flags;


	spin_lock_irqsave (&priv->write_urb_pool_lock, flags);

	for (i = 0; i < NUM_URBS; i++) {
		if (priv->write_urb_pool[i]->status != -EINPROGRESS) {
			room += URB_TRANSFER_BUFFER_SIZE - priv->write_offset;
		}
	}
	
	spin_unlock_irqrestore (&priv->write_urb_pool_lock, flags);

	dbg("%s - returns %d", __FUNCTION__, room);	
	return(room);
} /* ftdi_write_room */


static int ftdi_chars_in_buffer (struct usb_serial_port *port)
{ /* ftdi_chars_in_buffer */
	unsigned long flags;
	int i;
	int chars = 0;
	struct ftdi_private *priv = (struct ftdi_private *)port->private;
	int data_offset = priv->write_offset;

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

	spin_lock_irqsave (&priv->write_urb_pool_lock, flags);

	/* tally up the number of bytes waiting */
	for (i = 0; i < NUM_URBS; ++i) {
		if (priv->write_urb_pool[i]->status == -EINPROGRESS) {
			chars += URB_TRANSFER_BUFFER_SIZE - data_offset;
		}
	}

	spin_unlock_irqrestore (&priv->write_urb_pool_lock, flags);

	dbg("%s - returns %d", __FUNCTION__, chars);

	return (chars);

} /* ftdi_chars_in_buffer */



static void ftdi_read_bulk_callback (struct urb *urb)
{ /* ftdi_read_bulk_callback */
	struct usb_serial_port *port = (struct usb_serial_port *)urb->context;
	struct usb_serial *serial = get_usb_serial(port,__FUNCTION__);
       	struct tty_struct *tty = port->tty ;
	struct ftdi_private *priv = (struct ftdi_private *) port->private;
	char error_flag;
       	unsigned char *data = urb->transfer_buffer;

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

	dbg("%s", __FUNCTION__);

	if (port_paranoia_check (port, __FUNCTION__)) {
		return;
	}
	if (port->open_count <= 0)
		return;

	if (!serial){
		dbg("%s - bad serial pointer - exiting",__FUNCTION__);
		return;
	}
	
	if (!tty) {
		dbg("%s - bad tty pointer - exiting",__FUNCTION__);
		return;
	}


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

        /* The first two bytes of every read packet are status */
	if (urb->actual_length > 2) {
		usb_serial_debug_data (__FILE__, __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 */

	/* Compare new line status to the old one, signal if different */
	if (priv != NULL) {
		char new_status = data[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;
		}
	}

	/* 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[1] & FTDI_RS_OE ) { 
		error_flag = TTY_OVERRUN;
                dbg("OVERRRUN error");
	}
	if ( data[1] & FTDI_RS_BI ) { 
		error_flag = TTY_BREAK;
                dbg("BREAK received");
	}
	if ( data[1] & FTDI_RS_PE ) { 
		error_flag = TTY_PARITY;
                dbg("PARITY error");
	}
	if ( data[1] & FTDI_RS_FE ) { 
		error_flag = TTY_FRAME;
                dbg("FRAMING error");
	}
	if (urb->actual_length > data_offset) {

		for (i = data_offset ; i < urb->actual_length ; ++i) {
			/* have to make sure we don't overflow the buffer
			  with tty_insert_flip_char's */
			if(tty->flip.count >= TTY_FLIPBUF_SIZE) {
				tty_flip_buffer_push(tty);
			}
			/* 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[i], error_flag);
		}
	  	tty_flip_buffer_push(tty);
	} 

#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