io_edgeport.c

linux 内核源代码

	/* now copy our data */
	memcpy(&fifo->fifo[fifo->head], data, firsthalf);
	usb_serial_debug_data(debug, &port->dev, __FUNCTION__, firsthalf, &fifo->fifo[fifo->head]);

	// update the index and size
	fifo->head  += firsthalf;
	fifo->count += firsthalf;

	// wrap the index
	if (fifo->head == fifo->size) {
		fifo->head = 0;
	}

	secondhalf = copySize-firsthalf;

	if (secondhalf) {
		dbg("%s - copy rest of data %d", __FUNCTION__, secondhalf);
		memcpy(&fifo->fifo[fifo->head], &data[firsthalf], secondhalf);
		usb_serial_debug_data(debug, &port->dev, __FUNCTION__, secondhalf, &fifo->fifo[fifo->head]);
		// update the index and size
		fifo->count += secondhalf;
		fifo->head  += secondhalf;
		// No need to check for wrap since we can not get to end of fifo in this part
	}

finish_write:
	spin_unlock_irqrestore(&edge_port->ep_lock, flags);

	send_more_port_data((struct edgeport_serial *)usb_get_serial_data(port->serial), edge_port);

	dbg("%s wrote %d byte(s) TxCredits %d, Fifo %d", __FUNCTION__, copySize, edge_port->txCredits, fifo->count);

	return copySize;   
}


/************************************************************************
 *
 * send_more_port_data()
 *
 *	This routine attempts to write additional UART transmit data
 *	to a port over the USB bulk pipe. It is called (1) when new
 *	data has been written to a port's TxBuffer from higher layers
 *	(2) when the peripheral sends us additional TxCredits indicating
 *	that it can accept more	Tx data for a given port; and (3) when
 *	a bulk write completes successfully and we want to see if we
 *	can transmit more.
 *
 ************************************************************************/
static void send_more_port_data(struct edgeport_serial *edge_serial, struct edgeport_port *edge_port)
{
	struct TxFifo	*fifo = &edge_port->txfifo;
	struct urb	*urb;
	unsigned char	*buffer;
	int		status;
	int		count;
	int		bytesleft;
	int		firsthalf;
	int		secondhalf;
	unsigned long	flags;

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

	spin_lock_irqsave(&edge_port->ep_lock, flags);

	if (edge_port->write_in_progress ||
	    !edge_port->open             ||
	    (fifo->count == 0)) {
		dbg("%s(%d) EXIT - fifo %d, PendingWrite = %d", __FUNCTION__, edge_port->port->number, fifo->count, edge_port->write_in_progress);
		goto exit_send;
	}

	// since the amount of data in the fifo will always fit into the
	// edgeport buffer we do not need to check the write length

	//	Do we have enough credits for this port to make it worthwhile
	//	to bother queueing a write. If it's too small, say a few bytes,
	//	it's better to wait for more credits so we can do a larger
	//	write.
	if (edge_port->txCredits < EDGE_FW_GET_TX_CREDITS_SEND_THRESHOLD(edge_port->maxTxCredits,EDGE_FW_BULK_MAX_PACKET_SIZE)) {
		dbg("%s(%d) Not enough credit - fifo %d TxCredit %d", __FUNCTION__, edge_port->port->number, fifo->count, edge_port->txCredits );
		goto exit_send;
	}

	// lock this write
	edge_port->write_in_progress = true;

	// get a pointer to the write_urb
	urb = edge_port->write_urb;

	/* make sure transfer buffer is freed */
	kfree(urb->transfer_buffer);
	urb->transfer_buffer = NULL;

	/* build the data header for the buffer and port that we are about to send out */
	count = fifo->count;
	buffer = kmalloc (count+2, GFP_ATOMIC);
	if (buffer == NULL) {
		dev_err(&edge_port->port->dev, "%s - no more kernel memory...\n", __FUNCTION__);
		edge_port->write_in_progress = false;
		goto exit_send;
	}
	buffer[0] = IOSP_BUILD_DATA_HDR1 (edge_port->port->number - edge_port->port->serial->minor, count);
	buffer[1] = IOSP_BUILD_DATA_HDR2 (edge_port->port->number - edge_port->port->serial->minor, count);

	/* now copy our data */
	bytesleft =  fifo->size - fifo->tail;
	firsthalf = min (bytesleft, count);
	memcpy(&buffer[2], &fifo->fifo[fifo->tail], firsthalf);
	fifo->tail  += firsthalf;
	fifo->count -= firsthalf;
	if (fifo->tail == fifo->size) {
		fifo->tail = 0;
	}

	secondhalf = count-firsthalf;
	if (secondhalf) {
		memcpy(&buffer[2+firsthalf], &fifo->fifo[fifo->tail], secondhalf);
		fifo->tail  += secondhalf;
		fifo->count -= secondhalf;
	}

	if (count)
		usb_serial_debug_data(debug, &edge_port->port->dev, __FUNCTION__, count, &buffer[2]);

	/* fill up the urb with all of our data and submit it */
	usb_fill_bulk_urb (urb, edge_serial->serial->dev, 
		       usb_sndbulkpipe(edge_serial->serial->dev, edge_serial->bulk_out_endpoint),
		       buffer, count+2, edge_bulk_out_data_callback, edge_port);

	/* decrement the number of credits we have by the number we just sent */
	edge_port->txCredits -= count;
	edge_port->icount.tx += count;

	urb->dev = edge_serial->serial->dev;
	status = usb_submit_urb(urb, GFP_ATOMIC);
	if (status) {
		/* something went wrong */
		dev_err(&edge_port->port->dev, "%s - usb_submit_urb(write bulk) failed, status = %d, data lost\n", __FUNCTION__, status);
		edge_port->write_in_progress = false;

		/* revert the credits as something bad happened. */
		edge_port->txCredits += count;
		edge_port->icount.tx -= count;
	}
	dbg("%s wrote %d byte(s) TxCredit %d, Fifo %d", __FUNCTION__, count, edge_port->txCredits, fifo->count);

exit_send:
	spin_unlock_irqrestore(&edge_port->ep_lock, flags);
}


/*****************************************************************************
 * edge_write_room
 *	this function is called by the tty driver when it wants to know how many
 *	bytes of data we can accept for a specific port.
 *	If successful, we return the amount of room that we have for this port
 *	(the txCredits), 
 *	Otherwise we return a negative error number.
 *****************************************************************************/
static int edge_write_room (struct usb_serial_port *port)
{
	struct edgeport_port *edge_port = usb_get_serial_port_data(port);
	int room;
	unsigned long flags;

	dbg("%s", __FUNCTION__);

	if (edge_port == NULL)
		return -ENODEV;
	if (edge_port->closePending)
		return -ENODEV;

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

	if (!edge_port->open) {
		dbg("%s - port not opened", __FUNCTION__);
		return -EINVAL;
	}

	// total of both buffers is still txCredit
	spin_lock_irqsave(&edge_port->ep_lock, flags);
	room = edge_port->txCredits - edge_port->txfifo.count;
	spin_unlock_irqrestore(&edge_port->ep_lock, flags);

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


/*****************************************************************************
 * edge_chars_in_buffer
 *	this function is called by the tty driver when it wants to know how many
 *	bytes of data we currently have outstanding in the port (data that has
 *	been written, but hasn't made it out the port yet)
 *	If successful, we return the number of bytes left to be written in the 
 *	system, 
 *	Otherwise we return a negative error number.
 *****************************************************************************/
static int edge_chars_in_buffer (struct usb_serial_port *port)
{
	struct edgeport_port *edge_port = usb_get_serial_port_data(port);
	int num_chars;
	unsigned long flags;

	dbg("%s", __FUNCTION__);

	if (edge_port == NULL)
		return -ENODEV;
	if (edge_port->closePending)
		return -ENODEV;

	if (!edge_port->open) {
		dbg("%s - port not opened", __FUNCTION__);
		return -EINVAL;
	}

	spin_lock_irqsave(&edge_port->ep_lock, flags);
	num_chars = edge_port->maxTxCredits - edge_port->txCredits + edge_port->txfifo.count;
	spin_unlock_irqrestore(&edge_port->ep_lock, flags);
	if (num_chars) {
		dbg("%s(port %d) - returns %d", __FUNCTION__, port->number, num_chars);
	}

	return num_chars;
}


/*****************************************************************************
 * SerialThrottle
 *	this function is called by the tty driver when it wants to stop the data
 *	being read from the port.
 *****************************************************************************/
static void edge_throttle (struct usb_serial_port *port)
{
	struct edgeport_port *edge_port = usb_get_serial_port_data(port);
	struct tty_struct *tty;
	int status;

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

	if (edge_port == NULL)
		return;

	if (!edge_port->open) {
		dbg("%s - port not opened", __FUNCTION__);
		return;
	}

	tty = port->tty;
	if (!tty) {
		dbg ("%s - no tty available", __FUNCTION__);
		return;
	}

	/* if we are implementing XON/XOFF, send the stop character */
	if (I_IXOFF(tty)) {
		unsigned char stop_char = STOP_CHAR(tty);
		status = edge_write (port, &stop_char, 1);
		if (status <= 0) {
			return;
		}
	}

	/* if we are implementing RTS/CTS, toggle that line */
	if (tty->termios->c_cflag & CRTSCTS) {
		edge_port->shadowMCR &= ~MCR_RTS;
		status = send_cmd_write_uart_register(edge_port, MCR, edge_port->shadowMCR);
		if (status != 0) {
			return;
		}
	}

	return;
}


/*****************************************************************************
 * edge_unthrottle
 *	this function is called by the tty driver when it wants to resume the data
 *	being read from the port (called after SerialThrottle is called)
 *****************************************************************************/
static void edge_unthrottle (struct usb_serial_port *port)
{
	struct edgeport_port *edge_port = usb_get_serial_port_data(port);
	struct tty_struct *tty;
	int status;

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

	if (edge_port == NULL)
		return;

	if (!edge_port->open) {
		dbg("%s - port not opened", __FUNCTION__);
		return;
	}

	tty = port->tty;
	if (!tty) {
		dbg ("%s - no tty available", __FUNCTION__);
		return;
	}

	/* if we are implementing XON/XOFF, send the start character */
	if (I_IXOFF(tty)) {
		unsigned char start_char = START_CHAR(tty);
		status = edge_write (port, &start_char, 1);
		if (status <= 0) {
			return;
		}
	}

	/* if we are implementing RTS/CTS, toggle that line */
	if (tty->termios->c_cflag & CRTSCTS) {
		edge_port->shadowMCR |= MCR_RTS;
		status = send_cmd_write_uart_register(edge_port, MCR, edge_port->shadowMCR);
		if (status != 0) {
			return;
		}
	}

	return;
}


/*****************************************************************************
 * SerialSetTermios
 *	this function is called by the tty driver when it wants to change the termios structure
 *****************************************************************************/
static void edge_set_termios (struct usb_serial_port *port, struct ktermios *old_termios)
{
	/* FIXME: This function appears unused ?? */
	struct edgeport_port *edge_port = usb_get_serial_port_data(port);
	struct tty_struct *tty = port->tty;
	unsigned int cflag;

	cflag = tty->termios->c_cflag;
	dbg("%s - clfag %08x iflag %08x", __FUNCTION__, 
	    tty->termios->c_cflag, tty->termios->c_iflag);
	dbg("%s - old clfag %08x old iflag %08x", __FUNCTION__,
	    old_termios->c_cflag, old_termios->c_iflag);

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

	if (edge_port == NULL)
		return;

	if (!edge_port->open) {
		dbg("%s - port not opened", __FUNCTION__);
		return;
	}

	/* change the port settings to the new ones specified */
	change_port_settings (edge_port, old_termios);

	return;
}


/*****************************************************************************
 * get_lsr_info - get line status register info
 *
 * Purpose: Let user call ioctl() to get info when the UART physically
 * 	    is emptied.  On bus types like RS485, the transmitter must
 * 	    release the bus after transmitting. This must be done when
 * 	    the transmit shift register is empty, not be done when the
 * 	    transmit holding register is empty.  This functionality
 * 	    allows an RS485 driver to be written in user space. 
 *****************************************************************************/
static int get_lsr_info(struct edgeport_port *edge_port, unsigned int __user *value)
{
	unsigned int result = 0;
	unsigned long flags;

	spin_lock_irqsave(&edge_port->ep_lock, flags);
	if (edge_port->maxTxCredits == edge_port->txCredits &&
	    edge_port->txfifo.count == 0) {
		dbg("%s -- Empty", __FUNCTION__);
		result = TIOCSER_TEMT;
	}
	spin_unlock_irqrestore(&edge_port->ep_lock, flags);

	if (copy_to_user(value, &result, sizeof(int)))
		return -EFAULT;
	return 0;
}

static int get_number_bytes_avail(struct edgeport_port *edge_port, unsigned int __user *value)
{
	unsigned int result = 0;