io_edgeport.c

h内核

	__u32 lastCount;
	int timeout = HZ/10;
	int wait = 30;

	while (1) {
		// Save Last count
		lastCount = fifo->count;

		// Is the Edgeport Buffer empty?
		if (lastCount == 0) {
			dbg("%s - TX Buffer Empty", __FUNCTION__);
			return;
		}

		// Block the thread for a while
		interruptible_sleep_on_timeout (&edge_port->wait_chase, timeout);

		dbg("%s wait", __FUNCTION__);

		if (lastCount == fifo->count) {
			// No activity.. count down.
			wait--;
			if (wait == 0) {
				dbg("%s - TIMEOUT", __FUNCTION__);
				return;
			}
		} else {
			// Reset timout value back to seconds
			wait = 30;
		}
	}
}


/*****************************************************************************
 * edge_close
 *	this function is called by the tty driver when a port is closed
 *****************************************************************************/
static void edge_close (struct usb_serial_port *port, struct file * filp)
{
	struct edgeport_serial *edge_serial;
	struct edgeport_port *edge_port;
	int status;

	dbg("%s - port %d", __FUNCTION__, port->number);
			 
	edge_serial = usb_get_serial_data(port->serial);
	edge_port = usb_get_serial_port_data(port);
	if ((edge_serial == NULL) || (edge_port == NULL))
		return;
	
	// block until tx is empty
	block_until_tx_empty(edge_port);

	edge_port->closePending = TRUE;

	/* flush and chase */
	edge_port->chaseResponsePending = TRUE;

	dbg("%s - Sending IOSP_CMD_CHASE_PORT", __FUNCTION__);
	status = send_iosp_ext_cmd (edge_port, IOSP_CMD_CHASE_PORT, 0);
	if (status == 0) {
		// block until chase finished
		block_until_chase_response(edge_port);
	} else {
		edge_port->chaseResponsePending = FALSE;
	}

	/* close the port */
	dbg("%s - Sending IOSP_CMD_CLOSE_PORT", __FUNCTION__);
	send_iosp_ext_cmd (edge_port, IOSP_CMD_CLOSE_PORT, 0);

	//port->close = TRUE;
	edge_port->closePending = FALSE;
	edge_port->open = FALSE;
	edge_port->openPending = FALSE;

	if (edge_port->write_urb) {
		usb_kill_urb(edge_port->write_urb);
	}

	if (edge_port->write_urb) {
		/* if this urb had a transfer buffer already (old transfer) free it */
		if (edge_port->write_urb->transfer_buffer != NULL) {
			kfree(edge_port->write_urb->transfer_buffer);
		}
		usb_free_urb   (edge_port->write_urb);
		edge_port->write_urb = NULL;
	}
	if (edge_port->txfifo.fifo) {
		kfree(edge_port->txfifo.fifo);
		edge_port->txfifo.fifo = NULL;
	}

	dbg("%s exited", __FUNCTION__);
}   

/*****************************************************************************
 * SerialWrite
 *	this function is called by the tty driver when data should be written to
 *	the port.
 *	If successful, we return the number of bytes written, otherwise we return
 *	a negative error number.
 *****************************************************************************/
static int edge_write (struct usb_serial_port *port, const unsigned char *data, int count)
{
	struct edgeport_port *edge_port = usb_get_serial_port_data(port);
	struct TxFifo *fifo;
	int copySize;
	int bytesleft;
	int firsthalf;
	int secondhalf;
	unsigned long flags;

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

	if (edge_port == NULL)
		return -ENODEV;

	// get a pointer to the Tx fifo
	fifo = &edge_port->txfifo;

	spin_lock_irqsave(&edge_port->ep_lock, flags);

	// calculate number of bytes to put in fifo
	copySize = min ((unsigned int)count, (edge_port->txCredits - fifo->count));

	dbg("%s(%d) of %d byte(s) Fifo room  %d -- will copy %d bytes", __FUNCTION__, 
	    port->number, count, edge_port->txCredits - fifo->count, copySize);

	/* catch writes of 0 bytes which the tty driver likes to give us, and when txCredits is empty */
	if (copySize == 0) {
		dbg("%s - copySize = Zero", __FUNCTION__);
		goto finish_write;
	}

	// queue the data	
	// since we can never overflow the buffer we do not have to check for full condition

	// the copy is done is two parts -- first fill to the end of the buffer
	// then copy the reset from the start of the buffer 

	bytesleft = fifo->size - fifo->head;
	firsthalf = min (bytesleft, copySize);
	dbg("%s - copy %d bytes of %d into fifo ", __FUNCTION__, firsthalf, bytesleft);

	/* 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;

	/* if this urb had a transfer buffer already (old transfer) free it */
	if (urb->transfer_buffer != NULL) {
		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 == TRUE)
		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 == TRUE)
		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__);