empeg.c

linux2.4.20下的针对三星公司的s3c2410的usb模块驱动代码

	spin_unlock_irqrestore (&write_urb_pool_lock, flags);

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

	return (room);

}


static int empeg_chars_in_buffer (struct usb_serial_port *port)
{
	unsigned long flags;
	int i;
	int chars = 0;

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

	spin_lock_irqsave (&write_urb_pool_lock, flags);

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

	spin_unlock_irqrestore (&write_urb_pool_lock, flags);

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

	return (chars);

}


static void empeg_write_bulk_callback (struct urb *urb)
{
	struct usb_serial_port *port = (struct usb_serial_port *)urb->context;

	if (port_paranoia_check (port, __FUNCTION__))
		return;

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

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

	queue_task(&port->tqueue, &tq_immediate);
	mark_bh(IMMEDIATE_BH);

	return;

}


static void empeg_read_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__);
	struct tty_struct *tty;
	unsigned char *data = urb->transfer_buffer;
	int i;
	int result;

	if (port_paranoia_check (port, __FUNCTION__))
		return;

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

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

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

	usb_serial_debug_data (__FILE__, __FUNCTION__, urb->actual_length, data);

	tty = port->tty;

	if (urb->actual_length) {
		for (i = 0; i < urb->actual_length ; ++i) {
			/* gb - 2000/11/13
			 * If we insert too many characters we'll overflow the buffer.
			 * This means we'll lose bytes - Decidedly bad.
			 */
			if(tty->flip.count >= TTY_FLIPBUF_SIZE) {
				tty_flip_buffer_push(tty);
				}
			tty_insert_flip_char(tty, data[i], 0);
		}
		/* gb - 2000/11/13
		 * Goes straight through instead of scheduling - if tty->low_latency is set.
		 */
		tty_flip_buffer_push(tty);
		bytes_in += urb->actual_length;
	}

	/* Continue trying to always read  */
	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,
		empeg_read_bulk_callback,
		port);

	port->read_urb->transfer_flags |= USB_QUEUE_BULK;

	result = usb_submit_urb(port->read_urb);

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

	return;

}


static void empeg_throttle (struct usb_serial_port *port)
{
	dbg("%s - port %d", __FUNCTION__, port->number);
	usb_unlink_urb (port->read_urb);
}


static void empeg_unthrottle (struct usb_serial_port *port)
{
	int result;

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

	port->read_urb->dev = port->serial->dev;

	result = usb_submit_urb(port->read_urb);

	if (result)
		err("%s - failed submitting read urb, error %d", __FUNCTION__, result);

	return;
}


static int  empeg_startup (struct usb_serial *serial)
{

	dbg("%s", __FUNCTION__);

	dbg("%s - Set config to 1", __FUNCTION__);
	usb_set_configuration (serial->dev, 1);

	/* continue on with initialization */
	return 0;

}


static void empeg_shutdown (struct usb_serial *serial)
{
	dbg ("%s", __FUNCTION__);
}


static int empeg_ioctl (struct usb_serial_port *port, struct file * file, unsigned int cmd, unsigned long arg)
{
	dbg("%s - port %d, cmd 0x%.4x", __FUNCTION__, port->number, cmd);

	return -ENOIOCTLCMD;
}


static void empeg_set_termios (struct usb_serial_port *port, struct termios *old_termios)
{

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

	if ((!port->tty) || (!port->tty->termios)) {
		dbg("%s - no tty structures", __FUNCTION__);
		return;
	}

	/*
         * The empeg-car player wants these particular tty settings.
         * You could, for example, change the baud rate, however the
         * player only supports 115200 (currently), so there is really
         * no point in support for changes to the tty settings.
         * (at least for now)
         *
         * The default requirements for this device are:
         */
	port->tty->termios->c_iflag
		&= ~(IGNBRK	/* disable ignore break */
		| BRKINT	/* disable break causes interrupt */
		| PARMRK	/* disable mark parity errors */
		| ISTRIP	/* disable clear high bit of input characters */
		| INLCR		/* disable translate NL to CR */
		| IGNCR		/* disable ignore CR */
		| ICRNL		/* disable translate CR to NL */
		| IXON);	/* disable enable XON/XOFF flow control */

	port->tty->termios->c_oflag
		&= ~OPOST;	/* disable postprocess output characters */

	port->tty->termios->c_lflag
		&= ~(ECHO	/* disable echo input characters */
		| ECHONL	/* disable echo new line */
		| ICANON	/* disable erase, kill, werase, and rprnt special characters */
		| ISIG		/* disable interrupt, quit, and suspend special characters */
		| IEXTEN);	/* disable non-POSIX special characters */

	port->tty->termios->c_cflag
		&= ~(CSIZE	/* no size */
		| PARENB	/* disable parity bit */
		| CBAUD);	/* clear current baud rate */

	port->tty->termios->c_cflag
		|= (CS8		/* character size 8 bits */
		| B115200);	/* baud rate 115200 */

	/*
	 * Force low_latency on; otherwise the pushes are scheduled;
	 * this is bad as it opens up the possibility of dropping bytes
	 * on the floor.  We don't want to drop bytes on the floor. :)
	 */
	port->tty->low_latency = 1;

	/* Notify the tty driver that the termios have changed. */
	port->tty->ldisc.set_termios(port->tty, NULL);

	return;

}


static int __init empeg_init (void)
{
	struct urb *urb;
	int i;

	usb_serial_register (&empeg_device);

	/* create our write urb pool and transfer buffers */ 
	spin_lock_init (&write_urb_pool_lock);
	for (i = 0; i < NUM_URBS; ++i) {
		urb = usb_alloc_urb(0);
		write_urb_pool[i] = urb;
		if (urb == NULL) {
			err("No more urbs???");
			continue;
		}

		urb->transfer_buffer = NULL;
		urb->transfer_buffer = kmalloc (URB_TRANSFER_BUFFER_SIZE, GFP_KERNEL);
		if (!urb->transfer_buffer) {
			err("%s - out of memory for urb buffers.", 
			    __FUNCTION__);
			continue;
		}
	}

	info(DRIVER_VERSION ":" DRIVER_DESC);

	return 0;

}


static void __exit empeg_exit (void)
{
	int i;
	unsigned long flags;

	usb_serial_deregister (&empeg_device);

	spin_lock_irqsave (&write_urb_pool_lock, flags);

	for (i = 0; i < NUM_URBS; ++i) {
		if (write_urb_pool[i]) {
			/* FIXME - uncomment the following usb_unlink_urb call when
			 * the host controllers get fixed to set urb->dev = NULL after
			 * the urb is finished.  Otherwise this call oopses. */
			/* usb_unlink_urb(write_urb_pool[i]); */
			if (write_urb_pool[i]->transfer_buffer)
				kfree(write_urb_pool[i]->transfer_buffer);
			usb_free_urb (write_urb_pool[i]);
		}
	}

	spin_unlock_irqrestore (&write_urb_pool_lock, flags);

}


module_init(empeg_init);
module_exit(empeg_exit);

MODULE_AUTHOR( DRIVER_AUTHOR );
MODULE_DESCRIPTION( DRIVER_DESC );
MODULE_LICENSE("GPL");

MODULE_PARM(debug, "i");
MODULE_PARM_DESC(debug, "Debug enabled or not");