serial.c

h内核

	struct gs_port *port = tty->driver_data;
	int ret;

	if (port == NULL) {
		printk(KERN_ERR "gs_write: NULL port pointer\n");
		return -EIO;
	}

	gs_debug("gs_write: (%d,%p) writing %d bytes\n", port->port_num, tty,
		count);

	if (count == 0)
		return 0;

	spin_lock_irqsave(&port->port_lock, flags);

	if (port->port_dev == NULL) {
		printk(KERN_ERR "gs_write: (%d,%p) port is not connected\n",
			port->port_num, tty);
		ret = -EIO;
		goto exit;
	}

	if (port->port_open_count == 0) {
		printk(KERN_ERR "gs_write: (%d,%p) port is closed\n",
			port->port_num, tty);
		ret = -EBADF;
		goto exit;
	}

	count = gs_buf_put(port->port_write_buf, buf, count);

	spin_unlock_irqrestore(&port->port_lock, flags);

	gs_send(gs_device);

	gs_debug("gs_write: (%d,%p) wrote %d bytes\n", port->port_num, tty,
		count);

	return count;

exit:
	spin_unlock_irqrestore(&port->port_lock, flags);
	return ret;
}

/*
 * gs_put_char
 */
static void gs_put_char(struct tty_struct *tty, unsigned char ch)
{
	unsigned long flags;
	struct gs_port *port = tty->driver_data;

	if (port == NULL) {
		printk(KERN_ERR "gs_put_char: NULL port pointer\n");
		return;
	}

	gs_debug("gs_put_char: (%d,%p) char=0x%x, called from %p, %p, %p\n", port->port_num, tty, ch, __builtin_return_address(0), __builtin_return_address(1), __builtin_return_address(2));

	spin_lock_irqsave(&port->port_lock, flags);

	if (port->port_dev == NULL) {
		printk(KERN_ERR "gs_put_char: (%d,%p) port is not connected\n",
			port->port_num, tty);
		goto exit;
	}

	if (port->port_open_count == 0) {
		printk(KERN_ERR "gs_put_char: (%d,%p) port is closed\n",
			port->port_num, tty);
		goto exit;
	}

	gs_buf_put(port->port_write_buf, &ch, 1);

exit:
	spin_unlock_irqrestore(&port->port_lock, flags);
}

/*
 * gs_flush_chars
 */
static void gs_flush_chars(struct tty_struct *tty)
{
	unsigned long flags;
	struct gs_port *port = tty->driver_data;

	if (port == NULL) {
		printk(KERN_ERR "gs_flush_chars: NULL port pointer\n");
		return;
	}

	gs_debug("gs_flush_chars: (%d,%p)\n", port->port_num, tty);

	spin_lock_irqsave(&port->port_lock, flags);

	if (port->port_dev == NULL) {
		printk(KERN_ERR
			"gs_flush_chars: (%d,%p) port is not connected\n",
			port->port_num, tty);
		goto exit;
	}

	if (port->port_open_count == 0) {
		printk(KERN_ERR "gs_flush_chars: (%d,%p) port is closed\n",
			port->port_num, tty);
		goto exit;
	}

	spin_unlock_irqrestore(&port->port_lock, flags);

	gs_send(gs_device);

	return;

exit:
	spin_unlock_irqrestore(&port->port_lock, flags);
}

/*
 * gs_write_room
 */
static int gs_write_room(struct tty_struct *tty)
{

	int room = 0;
	unsigned long flags;
	struct gs_port *port = tty->driver_data;


	if (port == NULL)
		return 0;

	spin_lock_irqsave(&port->port_lock, flags);

	if (port->port_dev != NULL && port->port_open_count > 0
	&& port->port_write_buf != NULL)
		room = gs_buf_space_avail(port->port_write_buf);

	spin_unlock_irqrestore(&port->port_lock, flags);

	gs_debug("gs_write_room: (%d,%p) room=%d\n",
		port->port_num, tty, room);

	return room;
}

/*
 * gs_chars_in_buffer
 */
static int gs_chars_in_buffer(struct tty_struct *tty)
{
	int chars = 0;
	unsigned long flags;
	struct gs_port *port = tty->driver_data;

	if (port == NULL)
		return 0;

	spin_lock_irqsave(&port->port_lock, flags);

	if (port->port_dev != NULL && port->port_open_count > 0
	&& port->port_write_buf != NULL)
		chars = gs_buf_data_avail(port->port_write_buf);

	spin_unlock_irqrestore(&port->port_lock, flags);

	gs_debug("gs_chars_in_buffer: (%d,%p) chars=%d\n",
		port->port_num, tty, chars);

	return chars;
}

/*
 * gs_throttle
 */
static void gs_throttle(struct tty_struct *tty)
{
}

/*
 * gs_unthrottle
 */
static void gs_unthrottle(struct tty_struct *tty)
{
}

/*
 * gs_break
 */
static void gs_break(struct tty_struct *tty, int break_state)
{
}

/*
 * gs_ioctl
 */
static int gs_ioctl(struct tty_struct *tty, struct file *file, unsigned int cmd, unsigned long arg)
{
	struct gs_port *port = tty->driver_data;

	if (port == NULL) {
		printk(KERN_ERR "gs_ioctl: NULL port pointer\n");
		return -EIO;
	}

	gs_debug("gs_ioctl: (%d,%p,%p) cmd=0x%4.4x, arg=%lu\n",
		port->port_num, tty, file, cmd, arg);

	/* handle ioctls */

	/* could not handle ioctl */
	return -ENOIOCTLCMD;
}

/*
 * gs_set_termios
 */
static void gs_set_termios(struct tty_struct *tty, struct termios *old)
{
}

/*
* gs_send
*
* This function finds available write requests, calls
* gs_send_packet to fill these packets with data, and
* continues until either there are no more write requests
* available or no more data to send.  This function is
* run whenever data arrives or write requests are available.
*/
static int gs_send(struct gs_dev *dev)
{
	int ret,len;
	unsigned long flags;
	struct usb_ep *ep;
	struct usb_request *req;
	struct gs_req_entry *req_entry;

	if (dev == NULL) {
		printk(KERN_ERR "gs_send: NULL device pointer\n");
		return -ENODEV;
	}

	spin_lock_irqsave(&dev->dev_lock, flags);

	ep = dev->dev_in_ep;

	while(!list_empty(&dev->dev_req_list)) {

		req_entry = list_entry(dev->dev_req_list.next,
			struct gs_req_entry, re_entry);

		req = req_entry->re_req;

		len = gs_send_packet(dev, req->buf, ep->maxpacket);

		if (len > 0) {
gs_debug_level(3, "gs_send: len=%d, 0x%2.2x 0x%2.2x 0x%2.2x ...\n", len, *((unsigned char *)req->buf), *((unsigned char *)req->buf+1), *((unsigned char *)req->buf+2));
			list_del(&req_entry->re_entry);
			req->length = len;
			if ((ret=usb_ep_queue(ep, req, GFP_ATOMIC))) {
				printk(KERN_ERR
				"gs_send: cannot queue read request, ret=%d\n",
					ret);
				break;
			}
		} else {
			break;
		}

	}

	spin_unlock_irqrestore(&dev->dev_lock, flags);

	return 0;
}

/*
 * gs_send_packet
 *
 * If there is data to send, a packet is built in the given
 * buffer and the size is returned.  If there is no data to
 * send, 0 is returned.  If there is any error a negative
 * error number is returned.
 *
 * Called during USB completion routine, on interrupt time.
 *
 * We assume that disconnect will not happen until all completion
 * routines have completed, so we can assume that the dev_port
 * array does not change during the lifetime of this function.
 */
static int gs_send_packet(struct gs_dev *dev, char *packet, unsigned int size)
{
	unsigned int len;
	struct gs_port *port;

	/* TEMPORARY -- only port 0 is supported right now */
	port = dev->dev_port[0];

	if (port == NULL) {
		printk(KERN_ERR
			"gs_send_packet: port=%d, NULL port pointer\n",
			0);
		return -EIO;
	}

	spin_lock(&port->port_lock);

	len = gs_buf_data_avail(port->port_write_buf);
	if (len < size)
		size = len;

	if (size == 0)
		goto exit;

	size = gs_buf_get(port->port_write_buf, packet, size);

	if (port->port_tty)
		wake_up_interruptible(&port->port_tty->write_wait);

exit:
	spin_unlock(&port->port_lock);
	return size;
}

/*
 * gs_recv_packet
 *
 * Called for each USB packet received.  Reads the packet
 * header and stuffs the data in the appropriate tty buffer.
 * Returns 0 if successful, or a negative error number.
 *
 * Called during USB completion routine, on interrupt time.
 *
 * We assume that disconnect will not happen until all completion
 * routines have completed, so we can assume that the dev_port
 * array does not change during the lifetime of this function.
 */
static int gs_recv_packet(struct gs_dev *dev, char *packet, unsigned int size)
{
	unsigned int len;
	struct gs_port *port;
	int ret;

	/* TEMPORARY -- only port 0 is supported right now */
	port = dev->dev_port[0];

	if (port == NULL) {
		printk(KERN_ERR "gs_recv_packet: port=%d, NULL port pointer\n",
			port->port_num);
		return -EIO;
	}

	spin_lock(&port->port_lock);

	if (port->port_open_count == 0) {
		printk(KERN_ERR "gs_recv_packet: port=%d, port is closed\n",
			port->port_num);
		ret = -EIO;
		goto exit;
	}

	if (port->port_tty == NULL) {
		printk(KERN_ERR "gs_recv_packet: port=%d, NULL tty pointer\n",
			port->port_num);
		ret = -EIO;
		goto exit;
	}

	if (port->port_tty->magic != TTY_MAGIC) {
		printk(KERN_ERR "gs_recv_packet: port=%d, bad tty magic\n",
			port->port_num);
		ret = -EIO;
		goto exit;
	}

	len = (unsigned int)(TTY_FLIPBUF_SIZE - port->port_tty->flip.count);
	if (len < size)
		size = len;

	if (size > 0) {
		memcpy(port->port_tty->flip.char_buf_ptr, packet, size);
		port->port_tty->flip.char_buf_ptr += size;
		port->port_tty->flip.count += size;
		tty_flip_buffer_push(port->port_tty);
		wake_up_interruptible(&port->port_tty->read_wait);
	}

	ret = 0;

exit:
	spin_unlock(&port->port_lock);
	return ret;
}

/*
* gs_read_complete
*/
static void gs_read_complete(struct usb_ep *ep, struct usb_request *req)
{
	int ret;
	struct gs_dev *dev = ep->driver_data;

	if (dev == NULL) {
		printk(KERN_ERR "gs_read_complete: NULL device pointer\n");
		return;
	}

	switch(req->status) {
	case 0:
 		/* normal completion */
		gs_recv_packet(dev, req->buf, req->actual);
requeue:
		req->length = ep->maxpacket;
		if ((ret=usb_ep_queue(ep, req, GFP_ATOMIC))) {
			printk(KERN_ERR
			"gs_read_complete: cannot queue read request, ret=%d\n",
				ret);
		}
		break;

	case -ESHUTDOWN:
		/* disconnect */
		gs_debug("gs_read_complete: shutdown\n");
		gs_free_req(ep, req);
		break;

	default:
		/* unexpected */
		printk(KERN_ERR
		"gs_read_complete: unexpected status error, status=%d\n",
			req->status);
		goto requeue;
		break;
	}
}

/*
* gs_write_complete
*/
static void gs_write_complete(struct usb_ep *ep, struct usb_request *req)
{
	struct gs_dev *dev = ep->driver_data;
	struct gs_req_entry *gs_req = req->context;

	if (dev == NULL) {
		printk(KERN_ERR "gs_write_complete: NULL device pointer\n");
		return;
	}

	switch(req->status) {
	case 0:
		/* normal completion */
requeue:
		if (gs_req == NULL) {
			printk(KERN_ERR
				"gs_write_complete: NULL request pointer\n");
			return;
		}

		spin_lock(&dev->dev_lock);
		list_add(&gs_req->re_entry, &dev->dev_req_list);
		spin_unlock(&dev->dev_lock);

		gs_send(dev);

		break;

	case -ESHUTDOWN:
		/* disconnect */
		gs_debug("gs_write_complete: shutdown\n");
		gs_free_req(ep, req);
		break;

	default:
		printk(KERN_ERR
		"gs_write_complete: unexpected status error, status=%d\n",
			req->status);
		goto requeue;
		break;
	}
}

/* Gadget Driver */

/*
 * gs_bind
 *
 * Called on module load.  Allocates and initializes the device
 * structure and a control request.
 */
static int gs_bind(struct usb_gadget *gadget)
{
	int ret;
	struct usb_ep *ep;
	struct gs_dev *dev;