/*****************************************************************************
 *
 * Filename:      irda-usb.c
 * Version:       0.9b
 * Description:   IrDA-USB Driver
 * Status:        Experimental 
 * Author:        Dag Brattli <dag@brattli.net>
 *
 *	Copyright (C) 2000, Roman Weissgaerber <weissg@vienna.at>
 *      Copyright (C) 2001, Dag Brattli <dag@brattli.net>
 *      Copyright (C) 2001, Jean Tourrilhes <jt@hpl.hp.com>
 *          
 *	This program is free software; you can redistribute it and/or modify
 *	it under the terms of the GNU General Public License as published by
 *	the Free Software Foundation; either version 2 of the License, or
 *	(at your option) any later version.
 *
 *	This program is distributed in the hope that it will be useful,
 *	but WITHOUT ANY WARRANTY; without even the implied warranty of
 *	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *	GNU General Public License for more details.
 *
 *	You should have received a copy of the GNU General Public License
 *	along with this program; if not, write to the Free Software
 *	Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 *****************************************************************************/

/*
 *			    IMPORTANT NOTE
 *			    --------------
 *
 * As of kernel 2.4.10, this is the state of compliance and testing of
 * this driver (irda-usb) with regards to the USB low level drivers...
 *
 * This driver has been tested SUCCESSFULLY with the following drivers :
 *	o usb-uhci	(For Intel/Via USB controllers)
 *	o usb-ohci	(For other USB controllers)
 *
 * This driver has NOT been tested with the following drivers :
 *	o usb-ehci	(USB 2.0 controllers)
 *
 * This driver WON'T WORK with the following drivers :
 *	o uhci		(Alternate/JE driver for Intel/Via USB controllers)
 * Amongst the reasons :
 *	o uhci doesn't implement USB_ZERO_PACKET
 *	o uhci non-compliant use of urb->timeout
 * The final fix for USB_ZERO_PACKET in uhci is likely to be in 2.4.19 and
 * 2.5.8. With this fix, the driver will work properly. More on that later.
 *
 * Jean II
 */

/*------------------------------------------------------------------*/

#include <linux/module.h>

#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/init.h>
#include <linux/skbuff.h>
#include <linux/netdevice.h>
#include <linux/slab.h>
#include <linux/rtnetlink.h>
#include <linux/usb.h>

#include <net/irda/irda.h>
#include <net/irda/irlap.h>
#include <net/irda/irda_device.h>
#include <net/irda/wrapper.h>

#include <net/irda/irda-usb.h>

/*------------------------------------------------------------------*/

static int qos_mtt_bits = 0;

/* Master instance for each hardware found */
#define NIRUSB 4		/* Max number of USB-IrDA dongles */
static struct irda_usb_cb irda_instance[NIRUSB];

/* These are the currently known IrDA USB dongles. Add new dongles here */
static struct usb_device_id dongles[] = {
	/* ACTiSYS Corp,  ACT-IR2000U FIR-USB Adapter */
	{ USB_DEVICE(0x9c4, 0x011), driver_info: IUC_SPEED_BUG | IUC_NO_WINDOW },
	/* KC Technology Inc.,  KC-180 USB IrDA Device */
	{ USB_DEVICE(0x50f, 0x180), driver_info: IUC_SPEED_BUG | IUC_NO_WINDOW },
	/* Extended Systems, Inc.,  XTNDAccess IrDA USB (ESI-9685) */
	{ USB_DEVICE(0x8e9, 0x100), driver_info: IUC_SPEED_BUG | IUC_NO_WINDOW },
	{ match_flags: USB_DEVICE_ID_MATCH_INT_CLASS |
	               USB_DEVICE_ID_MATCH_INT_SUBCLASS,
	  bInterfaceClass: USB_CLASS_APP_SPEC,
	  bInterfaceSubClass: USB_CLASS_IRDA,
	  driver_info: IUC_DEFAULT, },
	{ }, /* The end */
};

/*
 * Important note :
 * Devices based on the SigmaTel chipset (0x66f, 0x4200) are not compliant
 * with the USB-IrDA specification (and actually very very different), and
 * there is no way this driver can support those devices, apart from
 * a complete rewrite...
 * Jean II
 */

MODULE_DEVICE_TABLE(usb, dongles);

/*------------------------------------------------------------------*/

static struct irda_class_desc *irda_usb_find_class_desc(struct usb_device *dev, unsigned int ifnum);
static void irda_usb_disconnect(struct usb_device *dev, void *ptr);
static void irda_usb_change_speed_xbofs(struct irda_usb_cb *self);
static int irda_usb_hard_xmit(struct sk_buff *skb, struct net_device *dev);
static int irda_usb_open(struct irda_usb_cb *self);
static int irda_usb_close(struct irda_usb_cb *self);
static void speed_bulk_callback(struct urb *urb);
static void write_bulk_callback(struct urb *urb);
static void irda_usb_receive(struct urb *urb);
static int irda_usb_net_init(struct net_device *dev);
static int irda_usb_net_open(struct net_device *dev);
static int irda_usb_net_close(struct net_device *dev);
static int irda_usb_net_ioctl(struct net_device *dev, struct ifreq *rq, int cmd);
static void irda_usb_net_timeout(struct net_device *dev);
static struct net_device_stats *irda_usb_net_get_stats(struct net_device *dev);

/************************ TRANSMIT ROUTINES ************************/
/*
 * Receive packets from the IrDA stack and send them on the USB pipe.
 * Handle speed change, timeout and lot's of uglyness...
 */

/*------------------------------------------------------------------*/
/*
 * Function irda_usb_build_header(self, skb, header)
 *
 *   Builds USB-IrDA outbound header
 *
 * When we send an IrDA frame over an USB pipe, we add to it a 1 byte
 * header. This function create this header with the proper values.
 *
 * Important note : the USB-IrDA spec 1.0 say very clearly in chapter 5.4.2.2
 * that the setting of the link speed and xbof number in this outbound header
 * should be applied *AFTER* the frame has been sent.
 * Unfortunately, some devices are not compliant with that... It seems that
 * reading the spec is far too difficult...
 * Jean II
 */
static void irda_usb_build_header(struct irda_usb_cb *self,
				  __u8 *header,
				  int	force)
{
	/* Set the negotiated link speed */
	if (self->new_speed != -1) {
		/* Hum... Ugly hack :-(
		 * Some device are not compliant with the spec and change
		 * parameters *before* sending the frame. - Jean II
		 */
		if ((self->capability & IUC_SPEED_BUG) &&
		    (!force) && (self->speed != -1)) {
			/* No speed and xbofs change here
			 * (we'll do it later in the write callback) */
			IRDA_DEBUG(2, "%s(), not changing speed yet\n", __FUNCTION__);
			*header = 0;
			return;
		}

		IRDA_DEBUG(2, "%s(), changing speed to %d\n", __FUNCTION__, self->new_speed);
		self->speed = self->new_speed;
		self->new_speed = -1;

		switch (self->speed) {
		case 2400:
		        *header = SPEED_2400;
			break;
		default:
		case 9600:
			*header = SPEED_9600;
			break;
		case 19200:
			*header = SPEED_19200;
			break;
		case 38400:
			*header = SPEED_38400;
			break;
		case 57600:
		        *header = SPEED_57600;
			break;
		case 115200:
		        *header = SPEED_115200;
			break;
		case 576000:
		        *header = SPEED_576000;
			break;
		case 1152000:
		        *header = SPEED_1152000;
			break;
		case 4000000:
		        *header = SPEED_4000000;
			self->new_xbofs = 0;
			break;
		}
	} else
		/* No change */
		*header = 0;
	
	/* Set the negotiated additional XBOFS */
	if (self->new_xbofs != -1) {
		IRDA_DEBUG(2, "%s(), changing xbofs to %d\n", __FUNCTION__, self->new_xbofs);
		self->xbofs = self->new_xbofs;
		self->new_xbofs = -1;

		switch (self->xbofs) {
		case 48:
			*header |= 0x10;
			break;
		case 28:
		case 24:	/* USB spec 1.0 says 24 */
			*header |= 0x20;
			break;
		default:
		case 12:
			*header |= 0x30;
			break;
		case 5: /* Bug in IrLAP spec? (should be 6) */
		case 6:
			*header |= 0x40;
			break;
		case 3:
			*header |= 0x50;
			break;
		case 2:
			*header |= 0x60;
			break;
		case 1:
			*header |= 0x70;
			break;
		case 0:
			*header |= 0x80;
			break;
		}
	}
}

/*------------------------------------------------------------------*/
/*
 * Send a command to change the speed of the dongle
 * Need to be called with spinlock on.
 */
static void irda_usb_change_speed_xbofs(struct irda_usb_cb *self)
{
	__u8 *frame;
	int ret;
	struct urb *purb;

	IRDA_DEBUG(2, "%s(), speed=%d, xbofs=%d\n",
		__FUNCTION__, self->new_speed, self->new_xbofs);

	/* Grab the speed URB */
	purb = &self->speed_urb;
	if (purb->status != USB_ST_NOERROR) {
		WARNING("%s(), URB still in use!\n", __FUNCTION__);
		return;
	}

	/* Allocate the fake frame */
	frame = self->speed_buff;

	/* Set the new speed and xbofs in this fake frame */
	irda_usb_build_header(self, frame, 1);

	/* Submit the 0 length IrDA frame to trigger new speed settings */
        FILL_BULK_URB(purb, self->usbdev,
		      usb_sndbulkpipe(self->usbdev, self->bulk_out_ep),
                      frame, IRDA_USB_SPEED_MTU,
                      speed_bulk_callback, self);
	purb->transfer_buffer_length = USB_IRDA_HEADER;
	purb->transfer_flags = USB_QUEUE_BULK | USB_ASYNC_UNLINK;
	purb->timeout = MSECS_TO_JIFFIES(100);

	if ((ret = usb_submit_urb(purb))) {
		WARNING("%s(), failed Speed URB\n", __FUNCTION__);
	}
}

/*------------------------------------------------------------------*/
/*
 * Note : this function will be called with both speed_urb and empty_urb...
 */
static void speed_bulk_callback(struct urb *purb)
{
	struct irda_usb_cb *self = purb->context;
	
	IRDA_DEBUG(2, "%s()\n", __FUNCTION__);

	/* We should always have a context */
	if (self == NULL) {
		WARNING("%s(), Bug : self == NULL\n", __FUNCTION__);
		return;
	}

	/* Check for timeout and other USB nasties */
	if(purb->status != USB_ST_NOERROR) {
		/* I get a lot of -ECONNABORTED = -103 here - Jean II */
		IRDA_DEBUG(0, "%s(), URB complete status %d, transfer_flags 0x%04X\n", __FUNCTION__, purb->status, purb->transfer_flags);

		/* Don't do anything here, that might confuse the USB layer.
		 * Instead, we will wait for irda_usb_net_timeout(), the
		 * network layer watchdog, to fix the situation.
		 * Jean II */
		/* A reset of the dongle might be welcomed here - Jean II */
		return;
	}

	/* urb is now available */
	purb->status = USB_ST_NOERROR;

	/* If it was the speed URB, allow the stack to send more packets */
	if(purb == &self->speed_urb) {
		netif_wake_queue(self->netdev);
	}
}

/*------------------------------------------------------------------*/
/*
 * Send an IrDA frame to the USB dongle (for transmission)
 */
static int irda_usb_hard_xmit(struct sk_buff *skb, struct net_device *netdev)
{
	struct irda_usb_cb *self = netdev->priv;
	struct urb *purb = &self->tx_urb;
	unsigned long flags;
	s32 speed;
	s16 xbofs;
	int res, mtt;

	netif_stop_queue(netdev);

	/* Protect us from USB callbacks, net watchdog and else. */
	spin_lock_irqsave(&self->lock, flags);

	/* Check if the device is still there.
	 * We need to check self->present under the spinlock because
	 * of irda_usb_disconnect() is synchronous - Jean II */
	if ((!self) || (!self->present)) {
		IRDA_DEBUG(0, "%s(), Device is gone...\n", __FUNCTION__);
		spin_unlock_irqrestore(&self->lock, flags);
		return 1;	/* Failed */
	}

	/* Check if we need to change the number of xbofs */
        xbofs = irda_get_next_xbofs(skb);
        if ((xbofs != self->xbofs) && (xbofs != -1)) {
		self->new_xbofs = xbofs;
	}

        /* Check if we need to change the speed */
	speed = irda_get_next_speed(skb);
	if ((speed != self->speed) && (speed != -1)) {
		/* Set the desired speed */
		self->new_speed = speed;

		/* Check for empty frame */
		if (!skb->len) {
			/* IrLAP send us an empty frame to make us change the
			 * speed. Changing speed with the USB adapter is in
			 * fact sending an empty frame to the adapter, so we
			 * could just let the present function do its job.
			 * However, we would wait for min turn time,
			 * do an extra memcpy and increment packet counters...
			 * Jean II */
			irda_usb_change_speed_xbofs(self);
			netdev->trans_start = jiffies;
			/* Will netif_wake_queue() in callback */
			goto drop;
		}
	}

	if (purb->status != USB_ST_NOERROR) {
		WARNING("%s(), URB still in use!\n", __FUNCTION__);
		goto drop;
	}

	/* Make sure there is room for IrDA-USB header. The actual
	 * allocation will be done lower in skb_push().
	 * Also, we don't use directly skb_cow(), because it require
	 * headroom >= 16, which force unnecessary copies - Jean II */
	if (skb_headroom(skb) < USB_IRDA_HEADER) {
		IRDA_DEBUG(0, "%s(), Insuficient skb headroom.\n", __FUNCTION__);
		if (skb_cow(skb, USB_IRDA_HEADER)) {
			WARNING("%s(), failed skb_cow() !!!\n", __FUNCTION__);
			goto drop;
		}
	}

	/* Change setting for next frame */
	irda_usb_build_header(self, skb_push(skb, USB_IRDA_HEADER), 0);

	/* FIXME: Make macro out of this one */
	((struct irda_skb_cb *)skb->cb)->context = self;

        FILL_BULK_URB(purb, self->usbdev, 
		      usb_sndbulkpipe(self->usbdev, self->bulk_out_ep),
                      skb->data, IRDA_USB_MAX_MTU,
                      write_bulk_callback, skb);
	purb->transfer_buffer_length = skb->len;
	/* Note : unlink *must* be Asynchronous because of the code in 
	 * irda_usb_net_timeout() -> call in irq - Jean II */
	purb->transfer_flags = USB_QUEUE_BULK | USB_ASYNC_UNLINK;
	/* This flag (USB_ZERO_PACKET) indicates that what we send is not
	 * a continuous stream of data but separate packets.
	 * In this case, the USB layer will insert an empty USB frame (TD)
	 * after each of our packets that is exact multiple of the frame size.
	 * This is how the dongle will detect the end of packet - Jean II */
	purb->transfer_flags |= USB_ZERO_PACKET;
	/* Timeout need to be shorter than NET watchdog timer */
	purb->timeout = MSECS_TO_JIFFIES(200);

	/* Generate min turn time. FIXME: can we do better than this? */
	/* Trying to a turnaround time at this level is trying to measure
	 * processor clock cycle with a wrist-watch, approximate at best...
	 *
	 * What we know is the last time we received a frame over USB.
	 * Due to latency over USB that depend on the USB load, we don't
	 * know when this frame was received over IrDA (a few ms before ?)
	 * Then, same story for our outgoing frame...
	 *
	 * In theory, the USB dongle is supposed to handle the turnaround
	 * by itself (spec 1.0, chater 4, page 6). Who knows ??? That's
	 * why this code is enabled only for dongles that doesn't meet
	 * the spec.
	 * Jean II */
	if (self->capability & IUC_NO_TURN) {
		mtt = irda_get_mtt(skb);
		if (mtt) {
			int diff;
			do_gettimeofday(&self->now);
			diff = self->now.tv_usec - self->stamp.tv_usec;
#ifdef IU_USB_MIN_RTT
			/* Factor in USB delays -> Get rid of udelay() that
			 * would be lost in the noise - Jean II */
			diff += IU_USB_MIN_RTT;
#endif /* IU_USB_MIN_RTT */
			if (diff < 0)
				diff += 1000000;

		        /* Check if the mtt is larger than the time we have
			 * already used by all the protocol processing
			 */
			if (mtt > diff) {
				mtt -= diff;
				if (mtt > 1000)
					mdelay(mtt/1000);
				else
					udelay(mtt);
			}
		}
	}
	
	/* Ask USB to send the packet */
	if ((res = usb_submit_urb(purb))) {
		WARNING("%s(), failed Tx URB\n", __FUNCTION__);
		self->stats.tx_errors++;
		/* Let USB recover : We will catch that in the watchdog */
		/*netif_start_queue(netdev);*/
	} else {
		/* Increment packet stats */
		self->stats.tx_packets++;
                self->stats.tx_bytes += skb->len;
		
		netdev->trans_start = jiffies;
	}
	spin_unlock_irqrestore(&self->lock, flags);
	
	return 0;

drop:
	/* Drop silently the skb and exit */
	dev_kfree_skb(skb);
	spin_unlock_irqrestore(&self->lock, flags);
	return 0;
}

/*------------------------------------------------------------------*/
/*
 * Note : this function will be called only for tx_urb...
 */
static void write_bulk_callback(struct urb *purb)
{
	unsigned long flags;
	struct sk_buff *skb = purb->context;
	struct irda_usb_cb *self = ((struct irda_skb_cb *) skb->cb)->context;
	
	IRDA_DEBUG(2, "%s()\n", __FUNCTION__);

	/* We should always have a context */
	if (self == NULL) {
		WARNING("%s(), Bug : self == NULL\n", __FUNCTION__);
		return;
	}

	/* Free up the skb */
	dev_kfree_skb_any(skb);
	purb->context = NULL;

	/* Check for timeout and other USB nasties */
	if(purb->status != USB_ST_NOERROR) {
		/* I get a lot of -ECONNABORTED = -103 here - Jean II */
		IRDA_DEBUG(0, "%s(), URB complete status %d, transfer_flags 0x%04X\n", __FUNCTION__, purb->status, purb->transfer_flags);

		/* Don't do anything here, that might confuse the USB layer,
		 * and we could go in recursion and blow the kernel stack...
		 * Instead, we will wait for irda_usb_net_timeout(), the
		 * network layer watchdog, to fix the situation.
		 * Jean II */
		/* A reset of the dongle might be welcomed here - Jean II */
		return;
	}

	/* urb is now available */
	//purb->status = USB_ST_NOERROR; -> tested above

	/* Make sure we read self->present properly */
	spin_lock_irqsave(&self->lock, flags);

	/* If the network is closed, stop everything */
	if ((!self->netopen) || (!self->present)) {
		IRDA_DEBUG(0, "%s(), Network is gone...\n", __FUNCTION__);
		spin_unlock_irqrestore(&self->lock, flags);
		return;
	}

	/* If we need to change the speed or xbofs, do it now */
	if ((self->new_speed != -1) || (self->new_xbofs != -1)) {
		IRDA_DEBUG(1, "%s(), Changing speed now...\n", __FUNCTION__);
		irda_usb_change_speed_xbofs(self);
	} else {
		/* Otherwise, allow the stack to send more packets */
		netif_wake_queue(self->netdev);
	}
	spin_unlock_irqrestore(&self->lock, flags);
}

/*------------------------------------------------------------------*/
/*
 * Watchdog timer from the network layer.
 * After a predetermined timeout, if we don't give confirmation that
 * the packet has been sent (i.e. no call to netif_wake_queue()),
 * the network layer will call this function.
 * Note that URB that we submit have also a timeout. When the URB timeout
 * expire, the normal URB callback is called (write_bulk_callback()).
 */
static void irda_usb_net_timeout(struct net_device *netdev)
{
	unsigned long flags;
	struct irda_usb_cb *self = netdev->priv;
	struct urb *purb;
	int	done = 0;	/* If we have made any progress */

	IRDA_DEBUG(0, "%s(), Network layer thinks we timed out!\n", __FUNCTION__);

	/* Protect us from USB callbacks, net Tx and else. */
	spin_lock_irqsave(&self->lock, flags);

	if ((!self) || (!self->present)) {
		WARNING("%s(), device not present!\n", __FUNCTION__);
		netif_stop_queue(netdev);
		spin_unlock_irqrestore(&self->lock, flags);
		return;
	}

	/* Check speed URB */
	purb = &(self->speed_urb);
	if (purb->status != USB_ST_NOERROR) {
		IRDA_DEBUG(0, "%s: Speed change timed out, urb->status=%d, urb->transfer_flags=0x%04X\n", netdev->name, purb->status, purb->transfer_flags);

		switch (purb->status) {
		case USB_ST_URB_PENDING:	/* -EINPROGRESS == -115 */
			usb_unlink_urb(purb);
			/* Note : above will  *NOT* call netif_wake_queue()
			 * in completion handler, we will come back here.
			 * Jean II */
			done = 1;
			break;
		case -ECONNABORTED:		/* -103 */
		case -ECONNRESET:		/* -104 */
		case -ETIMEDOUT:		/* -110 */
		case -ENOENT:			/* -2 (urb unlinked by us)  */
		default:			/* ??? - Play safe */
			purb->status = USB_ST_NOERROR;
			netif_wake_queue(self->netdev);
			done = 1;
			break;
		}
	}

	/* Check Tx URB */
	purb = &(self->tx_urb);
	if (purb->status != USB_ST_NOERROR) {
		struct sk_buff *skb = purb->context;

		IRDA_DEBUG(0, "%s: Tx timed out, urb->status=%d, urb->transfer_flags=0x%04X\n", netdev->name, purb->status, purb->transfer_flags);

		/* Increase error count */
		self->stats.tx_errors++;

#ifdef IU_BUG_KICK_TIMEOUT
		/* Can't be a bad idea to reset the speed ;-) - Jean II */
		if(self->new_speed == -1)
			self->new_speed = self->speed;
		if(self->new_xbofs == -1)
			self->new_xbofs = self->xbofs;
		irda_usb_change_speed_xbofs(self);
#endif /* IU_BUG_KICK_TIMEOUT */

		switch (purb->status) {
		case USB_ST_URB_PENDING:	/* -EINPROGRESS == -115 */
			usb_unlink_urb(purb);
			/* Note : above will  *NOT* call netif_wake_queue()
			 * in completion handler, because purb->status will
			 * be -ENOENT. We will fix that at the next watchdog,
			 * leaving more time to USB to recover...
			 * Also, we are in interrupt, so we need to have
			 * USB_ASYNC_UNLINK to work properly...
			 * Jean II */
			done = 1;
			break;
		case -ECONNABORTED:		/* -103 */
		case -ECONNRESET:		/* -104 */
		case -ETIMEDOUT:		/* -110 */
		case -ENOENT:			/* -2 (urb unlinked by us)  */
		default:			/* ??? - Play safe */
			if(skb != NULL) {
				dev_kfree_skb_any(skb);
				purb->context = NULL;
			}
			purb->status = USB_ST_NOERROR;
			netif_wake_queue(self->netdev);
			done = 1;
			break;
		}
	}
	spin_unlock_irqrestore(&self->lock, flags);

	/* Maybe we need a reset */
	/* Note : Some drivers seem to use a usb_set_interface() when they
	 * need to reset the hardware. Hum...
	 */

	/* if(done == 0) */
}

/************************* RECEIVE ROUTINES *************************/
/*
 * Receive packets from the USB layer stack and pass them to the IrDA stack.
 * Try to work around USB failures...
 */

/*
 * Note :
 * Some of you may have noticed that most dongle have an interrupt in pipe
 * that we don't use. Here is the little secret...
 * When we hang a Rx URB on the bulk in pipe, it generates some USB traffic
 * in every USB frame. This is unnecessary overhead.
 * The interrupt in pipe will generate an event every time a packet is
 * received. Reading an interrupt pipe adds minimal overhead, but has some
 * latency (~1ms).
 * If we are connected (speed != 9600), we want to minimise latency, so
 * we just always hang the Rx URB and ignore the interrupt.
 * If we are not connected (speed == 9600), there is usually no Rx traffic,
 * and we want to minimise the USB overhead. In this case we should wait
 * on the interrupt pipe and hang the Rx URB only when an interrupt is
 * received.
 * Jean II
 */

/*------------------------------------------------------------------*/
/*
 * Submit a Rx URB to the USB layer to handle reception of a frame
 *
 * Important note :
 * The function process_urb() in usb-uhci.c contains the following code :
 * >	urb->complete ((struct urb *) urb);
 * >	// Re-submit the URB if ring-linked
 * >	if (is_ring && (urb->status != -ENOENT) && !contains_killed) {
 * >		urb->dev=usb_dev;
 * >		uhci_submit_urb (urb);
 * >	}
 * The way I see it is that if we submit more than one Rx URB at a
 * time, the Rx URB can be automatically re-submitted after the
 * completion handler is called.
 * We make sure to disable this feature by setting urb->next to NULL
 *
 * My take is that it's a questionable feature, and quite difficult
 * to control and to make work effectively.
 * The outcome (re-submited or not) depend on various complex
 * test ('is_ring' and 'contains_killed'), and the completion handler
 * don't have this information, so basically the driver has no way
 * to know if URB are resubmitted or not. Yuck !
 * If everything is perfect, it's cool, but the problem is when
 * an URB is killed (timeout, call to unlink_urb(), ...), things get
 * messy...
 * The other problem is that this scheme deal only with the URB
 * and ignore everything about the associated buffer. So, it would
 * resubmit URB even if the buffer is still in use or non-existent.
 * On the other hand, submitting ourself in the completion callback
 * is quite trivial and work well (this function).
 * Moreover, this scheme doesn't allow to have an idle URB, which is
 * necessary to overcome some URB failures.
 *
 * Jean II
 */
static void irda_usb_submit(struct irda_usb_cb *self, struct sk_buff *skb, struct urb *purb)
{
	struct irda_skb_cb *cb;
	int ret;

	IRDA_DEBUG(2, "%s()\n", __FUNCTION__);

	/* Check that we have an urb */
	if (!purb) {
		WARNING("%s(), Bug : purb == NULL\n", __FUNCTION__);
		return;
	}

	/* Allocate new skb if it has not been recycled */
	if (!skb) {
		skb = dev_alloc_skb(IRDA_USB_MAX_MTU + 1);
		if (!skb) {
			/* If this ever happen, we are in deep s***.
			 * Basically, the Rx path will stop... */
			WARNING("%s(), Failed to allocate Rx skb\n", __FUNCTION__);
			return;
		}
	} else  {
		/* Reset recycled skb */
		skb->data = skb->tail = skb->head;
		skb->len = 0;
	}
	/* Make sure IP header get aligned (IrDA header is 5 bytes ) */
	skb_reserve(skb, 1);

	/* Save ourselves */
	cb = (struct irda_skb_cb *) skb->cb;
	cb->context = self;

	/* Reinitialize URB */
	FILL_BULK_URB(purb, self->usbdev, 
		      usb_rcvbulkpipe(self->usbdev, self->bulk_in_ep), 
		      skb->data, skb->truesize,
                      irda_usb_receive, skb);
	purb->transfer_flags = USB_QUEUE_BULK;
	/* Note : unlink *must* be synchronous because of the code in 
	 * irda_usb_net_close() -> free the skb - Jean II */
	purb->status = USB_ST_NOERROR;
	purb->next = NULL;	/* Don't auto resubmit URBs */
	
	ret = usb_submit_urb(purb);
	if (ret) {
		/* If this ever happen, we are in deep s***.
		 * Basically, the Rx path will stop... */
		WARNING("%s(), Failed to submit Rx URB %d\n", __FUNCTION__, ret);
	}
}

/*------------------------------------------------------------------*/
/*
 * Function irda_usb_receive(purb)
 *
 *     Called by the USB subsystem when a frame has been received
 *
 */
static void irda_usb_receive(struct urb *purb) 
{
	struct sk_buff *skb = (struct sk_buff *) purb->context;
	struct irda_usb_cb *self; 
	struct irda_skb_cb *cb;
	struct sk_buff *new;
	
	IRDA_DEBUG(2, "%s(), len=%d\n", __FUNCTION__, purb->actual_length);
	
	/* Find ourselves */
	cb = (struct irda_skb_cb *) skb->cb;
	ASSERT(cb != NULL, return;);
	self = (struct irda_usb_cb *) cb->context;
	ASSERT(self != NULL, return;);

	/* If the network is closed or the device gone, stop everything */
	if ((!self->netopen) || (!self->present)) {
		IRDA_DEBUG(0, "%s(), Network is gone!\n", __FUNCTION__);
		/* Don't re-submit the URB : will stall the Rx path */
		return;
	}
	
	/* Check the status */
	if(purb->status != USB_ST_NOERROR) {
		switch (purb->status) {
		case USB_ST_CRC:		/* -EILSEQ */
			self->stats.rx_errors++;
			self->stats.rx_crc_errors++;	
			break;
		case -ECONNRESET:		/* -104 */
			IRDA_DEBUG(0, "%s(), Connection Reset (-104), transfer_flags 0x%04X \n", __FUNCTION__, purb->transfer_flags);
			/* uhci_cleanup_unlink() is going to kill the Rx
			 * URB just after we return. No problem, at this
			 * point the URB will be idle ;-) - Jean II */
			break;
		default:
			IRDA_DEBUG(0, "%s(), RX status %d,transfer_flags 0x%04X \n", __FUNCTION__, purb->status, purb->transfer_flags);
			break;
		}
		goto done;
	}
	
	/* Check for empty frames */
	if (purb->actual_length <= USB_IRDA_HEADER) {
		WARNING("%s(), empty frame!\n", __FUNCTION__);
		goto done;
	}

	/*  
	 * Remember the time we received this frame, so we can
	 * reduce the min turn time a bit since we will know
	 * how much time we have used for protocol processing
	 */
        do_gettimeofday(&self->stamp);

	/* Fix skb, and remove USB-IrDA header */
	skb_put(skb, purb->actual_length);
	skb_pull(skb, USB_IRDA_HEADER);

	/* Don't waste a lot of memory on small IrDA frames */
	if (skb->len < RX_COPY_THRESHOLD) {
		new = dev_alloc_skb(skb->len+1);
		if (!new) {
			self->stats.rx_dropped++;
			goto done;  
		}

		/* Make sure IP header get aligned (IrDA header is 5 bytes) */
		skb_reserve(new, 1);
		
		/* Copy packet, so we can recycle the original */
		memcpy(skb_put(new, skb->len), skb->data, skb->len);
		/* We will cleanup the skb in irda_usb_submit() */
	} else {
		/* Deliver the original skb */
		new = skb;
		skb = NULL;
	}
	
	self->stats.rx_bytes += new->len;
	self->stats.rx_packets++;

	/* Ask the networking layer to queue the packet for the IrDA stack */
        new->dev = self->netdev;
        new->mac.raw  = new->data;
        new->protocol = htons(ETH_P_IRDA);
        netif_rx(new);

done:
	/* Note : at this point, the URB we've just received (purb)
	 * is still referenced by the USB layer. For example, if we
	 * have received a -ECONNRESET, uhci_cleanup_unlink() will
	 * continue to process it (in fact, cleaning it up).
	 * If we were to submit this URB, disaster would ensue.
	 * Therefore, we submit our idle URB, and put this URB in our
	 * idle slot....
	 * Jean II */
	/* Note : with this scheme, we could submit the idle URB before
	 * processing the Rx URB. Another time... Jean II */

	/* Submit the idle URB to replace the URB we've just received */
	irda_usb_submit(self, skb, self->idle_rx_urb);
	/* Recycle Rx URB : Now, the idle URB is the present one */
	purb->context = NULL;
	self->idle_rx_urb = purb;
}

/*------------------------------------------------------------------*/
/*
 * Callbak from IrDA layer. IrDA wants to know if we have
 * started receiving anything.
 */
static int irda_usb_is_receiving(struct irda_usb_cb *self)
{
	/* Note : because of the way UHCI works, it's almost impossible
	 * to get this info. The Controller DMA directly to memory and
	 * signal only when the whole frame is finished. To know if the
	 * first TD of the URB has been filled or not seems hard work...
	 *
	 * The other solution would be to use the "receiving" command
	 * on the default decriptor with a usb_control_msg(), but that
	 * would add USB traffic and would return result only in the
	 * next USB frame (~1ms).
	 *
	 * I've been told that current dongles send status info on their
	 * interrupt endpoint, and that's what the Windows driver uses
	 * to know this info. Unfortunately, this is not yet in the spec...
	 *
	 * Jean II
	 */

	return 0; /* For now */
}

/********************** IRDA DEVICE CALLBACKS **********************/
/*
 * Main calls from the IrDA/Network subsystem.
 * Mostly registering a new irda-usb device and removing it....
 * We only deal with the IrDA side of the business, the USB side will
 * be dealt with below...
 */

/*------------------------------------------------------------------*/
/*
 * Callback when a new IrDA device is created.
 */
static int irda_usb_net_init(struct net_device *dev)
{
	IRDA_DEBUG(1, "%s()\n", __FUNCTION__);
	
	/* Set up to be a normal IrDA network device driver */
	irda_device_setup(dev);

	/* Insert overrides below this line! */

	return 0;
}

/*------------------------------------------------------------------*/
/*
 * Function irda_usb_net_open (dev)
 *
 *    Network device is taken up. Usually this is done by "ifconfig irda0 up" 
 *   
 * Note : don't mess with self->netopen - Jean II
 */
static int irda_usb_net_open(struct net_device *netdev)
{
	struct irda_usb_cb *self;
	char	hwname[16];
	int i;
	
	IRDA_DEBUG(1, "%s()\n", __FUNCTION__);

	ASSERT(netdev != NULL, return -1;);
	self = (struct irda_usb_cb *) netdev->priv;
	ASSERT(self != NULL, return -1;);

	/* Can only open the device if it's there */
	if(!self->present) {
		WARNING("%s(), device not present!\n", __FUNCTION__);
		return -1;
	}

	/* Initialise default speed and xbofs value
	 * (IrLAP will change that soon) */
	self->speed = -1;
	self->xbofs = -1;
	self->new_speed = -1;
	self->new_xbofs = -1;

	/* To do *before* submitting Rx urbs and starting net Tx queue
	 * Jean II */
	self->netopen = 1;

	/* 
	 * Now that everything should be initialized properly,
	 * Open new IrLAP layer instance to take care of us...
	 * Note : will send immediately a speed change...
	 */
	sprintf(hwname, "usb#%d", self->usbdev->devnum);
	self->irlap = irlap_open(netdev, &self->qos, hwname);
	ASSERT(self->irlap != NULL, return -1;);

	/* Allow IrLAP to send data to us */
	netif_start_queue(netdev);

	/* We submit all the Rx URB except for one that we keep idle.
	 * Need to be initialised before submitting other USBs, because
	 * in some cases as soon as we submit the URBs the USB layer
	 * will trigger a dummy receive - Jean II */
	self->idle_rx_urb = &(self->rx_urb[IU_MAX_ACTIVE_RX_URBS]);
	self->idle_rx_urb->context = NULL;

	/* Now that we can pass data to IrLAP, allow the USB layer
	 * to send us some data... */
	for (i = 0; i < IU_MAX_ACTIVE_RX_URBS; i++)
		irda_usb_submit(self, NULL, &(self->rx_urb[i]));

	/* Ready to play !!! */
	MOD_INC_USE_COUNT;
	return 0;
}

/*------------------------------------------------------------------*/
/*
 * Function irda_usb_net_close (self)
 *
 *    Network device is taken down. Usually this is done by 
 *    "ifconfig irda0 down" 
 */
static int irda_usb_net_close(struct net_device *netdev)
{
	struct irda_usb_cb *self;
	int	i;

	IRDA_DEBUG(1, "%s()\n", __FUNCTION__);

	ASSERT(netdev != NULL, return -1;);
	self = (struct irda_usb_cb *) netdev->priv;
	ASSERT(self != NULL, return -1;);

	/* Clear this flag *before* unlinking the urbs and *before*
	 * stopping the network Tx queue - Jean II */
	self->netopen = 0;

	/* Stop network Tx queue */
	netif_stop_queue(netdev);

	/* Deallocate all the Rx path buffers (URBs and skb) */
	for (i = 0; i < IU_MAX_RX_URBS; i++) {
		struct urb *purb = &(self->rx_urb[i]);
		struct sk_buff *skb = (struct sk_buff *) purb->context;
		/* Cancel the receive command */
		usb_unlink_urb(purb);
		/* The skb is ours, free it */
		if(skb) {
			dev_kfree_skb(skb);
			purb->context = NULL;
		}
	}
	/* Cancel Tx and speed URB - need to be synchronous to avoid races */
	self->tx_urb.transfer_flags &= ~USB_ASYNC_UNLINK;
	usb_unlink_urb(&(self->tx_urb));
	self->speed_urb.transfer_flags &= ~USB_ASYNC_UNLINK;
	usb_unlink_urb(&(self->speed_urb));

	/* Stop and remove instance of IrLAP */
	if (self->irlap)
		irlap_close(self->irlap);
	self->irlap = NULL;

	MOD_DEC_USE_COUNT;

	return 0;
}

/*------------------------------------------------------------------*/
/*
 * IOCTLs : Extra out-of-band network commands...
 */
static int irda_usb_net_ioctl(struct net_device *dev, struct ifreq *rq, int cmd)
{
	unsigned long flags;
	struct if_irda_req *irq = (struct if_irda_req *) rq;
	struct irda_usb_cb *self;
	int ret = 0;

	ASSERT(dev != NULL, return -1;);
	self = dev->priv;
	ASSERT(self != NULL, return -1;);

	IRDA_DEBUG(2, "%s(), %s, (cmd=0x%X)\n", __FUNCTION__, dev->name, cmd);

	switch (cmd) {
	case SIOCSBANDWIDTH: /* Set bandwidth */
		if (!capable(CAP_NET_ADMIN))
			return -EPERM;
		/* Protect us from USB callbacks, net watchdog and else. */
		spin_lock_irqsave(&self->lock, flags);
		/* Check if the device is still there */
		if(self->present) {
			/* Set the desired speed */
			self->new_speed = irq->ifr_baudrate;
			irda_usb_change_speed_xbofs(self);
		}
		spin_unlock_irqrestore(&self->lock, flags);
		break;
	case SIOCSMEDIABUSY: /* Set media busy */
		if (!capable(CAP_NET_ADMIN))
			return -EPERM;
		/* Check if the IrDA stack is still there */
		if(self->netopen)
			irda_device_set_media_busy(self->netdev, TRUE);
		break;
	case SIOCGRECEIVING: /* Check if we are receiving right now */
		irq->ifr_receiving = irda_usb_is_receiving(self);
		break;
	default:
		ret = -EOPNOTSUPP;
	}
	
	return ret;
}

/*------------------------------------------------------------------*/
/*
 * Get device stats (for /proc/net/dev and ifconfig)
 */
static struct net_device_stats *irda_usb_net_get_stats(struct net_device *dev)
{
	struct irda_usb_cb *self = dev->priv;
	return &self->stats;
}

/********************* IRDA CONFIG SUBROUTINES *********************/
/*
 * Various subroutines dealing with IrDA and network stuff we use to
 * configure and initialise each irda-usb instance.
 * These functions are used below in the main calls of the driver...
 */

/*------------------------------------------------------------------*/
/*
 * Set proper values in the IrDA QOS structure
 */
static inline void irda_usb_init_qos(struct irda_usb_cb *self)
{
	struct irda_class_desc *desc;

	IRDA_DEBUG(3, "%s()\n", __FUNCTION__);
	
	desc = self->irda_desc;
	
	/* Initialize QoS for this device */
	irda_init_max_qos_capabilies(&self->qos);

	self->qos.baud_rate.bits       = desc->wBaudRate;
	self->qos.min_turn_time.bits   = desc->bmMinTurnaroundTime;
	self->qos.additional_bofs.bits = desc->bmAdditionalBOFs;
	self->qos.window_size.bits     = desc->bmWindowSize;
	self->qos.data_size.bits       = desc->bmDataSize;

	IRDA_DEBUG(0, "%s(), dongle says speed=0x%X, size=0x%X, window=0x%X, bofs=0x%X, turn=0x%X\n", 
		__FUNCTION__, self->qos.baud_rate.bits, self->qos.data_size.bits, self->qos.window_size.bits, self->qos.additional_bofs.bits, self->qos.min_turn_time.bits);

	/* Don't always trust what the dongle tell us */
	if(self->capability & IUC_SIR_ONLY)
		self->qos.baud_rate.bits	&= 0xff;
	if(self->capability & IUC_SMALL_PKT)
		self->qos.data_size.bits	 = 0x07;
	if(self->capability & IUC_NO_WINDOW)
		self->qos.window_size.bits	 = 0x01;
	if(self->capability & IUC_MAX_WINDOW)
		self->qos.window_size.bits	 = 0x7f;
	if(self->capability & IUC_MAX_XBOFS)
		self->qos.additional_bofs.bits	 = 0x01;

#if 1
	/* Module parameter can override the rx window size */
	if (qos_mtt_bits)
		self->qos.min_turn_time.bits = qos_mtt_bits;
#endif	    
	/* 
	 * Note : most of those values apply only for the receive path,
	 * the transmit path will be set differently - Jean II 
	 */
	irda_qos_bits_to_value(&self->qos);

	self->flags |= IFF_SIR;
	if (self->qos.baud_rate.value > 115200)
		self->flags |= IFF_MIR;
	if (self->qos.baud_rate.value > 1152000)
		self->flags |= IFF_FIR;
	if (self->qos.baud_rate.value > 4000000)
		self->flags |= IFF_VFIR;
}

/*------------------------------------------------------------------*/
/*
 * Initialise the network side of the irda-usb instance
 * Called when a new USB instance is registered in irda_usb_probe()
 */
static inline int irda_usb_open(struct irda_usb_cb *self)
{
	struct net_device *netdev;
	int err;

	IRDA_DEBUG(1, "%s()\n", __FUNCTION__);

	spin_lock_init(&self->lock);

	irda_usb_init_qos(self);
	
	/* Initialise list of skb beeing curently transmitted */
	self->tx_list = hashbin_new(HB_GLOBAL);

	/* Allocate the buffer for speed changes */
	/* Don't change this buffer size and allocation without doing
	 * some heavy and complete testing. Don't ask why :-(
	 * Jean II */
	self->speed_buff = (char *) kmalloc(IRDA_USB_SPEED_MTU, GFP_KERNEL);
	if (self->speed_buff == NULL) 
		return -1;
	memset(self->speed_buff, 0, IRDA_USB_SPEED_MTU);

	/* Create a network device for us */
	if (!(netdev = dev_alloc("irda%d", &err))) {
		ERROR("%s(), dev_alloc() failed!\n", __FUNCTION__);
		return -1;
	}
	self->netdev = netdev;
 	netdev->priv = (void *) self;

	/* Override the network functions we need to use */
	netdev->init            = irda_usb_net_init;
	netdev->hard_start_xmit = irda_usb_hard_xmit;
	netdev->tx_timeout	= irda_usb_net_timeout;
	netdev->watchdog_timeo  = 250*HZ/1000;	/* 250 ms > USB timeout */
	netdev->open            = irda_usb_net_open;
	netdev->stop            = irda_usb_net_close;
	netdev->get_stats	= irda_usb_net_get_stats;
	netdev->do_ioctl        = irda_usb_net_ioctl;

	rtnl_lock();
	err = register_netdevice(netdev);
	rtnl_unlock();
	if (err) {
		ERROR("%s(), register_netdev() failed!\n", __FUNCTION__);
		return -1;
	}
	MESSAGE("IrDA: Registered device %s\n", netdev->name);

	return 0;
}

/*------------------------------------------------------------------*/
/*
 * Cleanup the network side of the irda-usb instance
 * Called when a USB instance is removed in irda_usb_disconnect()
 */
static inline int irda_usb_close(struct irda_usb_cb *self)
{
	IRDA_DEBUG(1, "%s()\n", __FUNCTION__);

	ASSERT(self != NULL, return -1;);

	/* Remove netdevice */
	if (self->netdev) {
		rtnl_lock();
		unregister_netdevice(self->netdev);
		self->netdev = NULL;
		rtnl_unlock();
	}
	/* Delete all pending skbs */
	hashbin_delete(self->tx_list, (FREE_FUNC) &dev_kfree_skb_any);
	/* Remove the speed buffer */
	if (self->speed_buff != NULL) {
		kfree(self->speed_buff);
		self->speed_buff = NULL;
	}

	return 0;
}

/********************** USB CONFIG SUBROUTINES **********************/
/*
 * Various subroutines dealing with USB stuff we use to configure and
 * initialise each irda-usb instance.
 * These functions are used below in the main calls of the driver...
 */

/*------------------------------------------------------------------*/
/*
 * Function irda_usb_parse_endpoints(dev, ifnum)
 *
 *    Parse the various endpoints and find the one we need.
 *
 * The endpoint are the pipes used to communicate with the USB device.
 * The spec defines 2 endpoints of type bulk transfer, one in, and one out.
 * These are used to pass frames back and forth with the dongle.
 * Most dongle have also an interrupt endpoint, that will be probably
 * documented in the next spec...
 */
static inline int irda_usb_parse_endpoints(struct irda_usb_cb *self, struct usb_endpoint_descriptor *endpoint, int ennum)
{
	int i;		/* Endpoint index in table */
		
	/* Init : no endpoints */
	self->bulk_in_ep = 0;
	self->bulk_out_ep = 0;
	self->bulk_int_ep = 0;

	/* Let's look at all those endpoints */
	for(i = 0; i < ennum; i++) {
		/* All those variables will get optimised by the compiler,
		 * so let's aim for clarity... - Jean II */
		__u8 ep;	/* Endpoint address */
		__u8 dir;	/* Endpoint direction */
		__u8 attr;	/* Endpoint attribute */
		__u16 psize;	/* Endpoint max packet size in bytes */

		/* Get endpoint address, direction and attribute */
		ep = endpoint[i].bEndpointAddress & USB_ENDPOINT_NUMBER_MASK;
		dir = endpoint[i].bEndpointAddress & USB_ENDPOINT_DIR_MASK;
		attr = endpoint[i].bmAttributes;
		psize = endpoint[i].wMaxPacketSize;

		/* Is it a bulk endpoint ??? */
		if(attr == USB_ENDPOINT_XFER_BULK) {
			/* We need to find an IN and an OUT */
			if(dir == USB_DIR_IN) {
				/* This is our Rx endpoint */
				self->bulk_in_ep = ep;
			} else {
				/* This is our Tx endpoint */
				self->bulk_out_ep = ep;
				self->bulk_out_mtu = psize;
			}
		} else {
			if((attr == USB_ENDPOINT_XFER_INT) &&
			   (dir == USB_DIR_IN)) {
				/* This is our interrupt endpoint */
				self->bulk_int_ep = ep;
			} else {
				ERROR("%s(), Unrecognised endpoint %02X.\n", __FUNCTION__, ep);
			}
		}
	}

	IRDA_DEBUG(0, "%s(), And our endpoints are : in=%02X, out=%02X (%d), int=%02X\n",
		__FUNCTION__, self->bulk_in_ep, self->bulk_out_ep, self->bulk_out_mtu, self->bulk_int_ep);
	/* Should be 8, 16, 32 or 64 bytes */
	ASSERT(self->bulk_out_mtu == 64, ;);

	return((self->bulk_in_ep != 0) && (self->bulk_out_ep != 0));
}

#ifdef IU_DUMP_CLASS_DESC
/*------------------------------------------------------------------*/
/*
 * Function usb_irda_dump_class_desc(desc)
 *
 *    Prints out the contents of the IrDA class descriptor
 *
 */
static inline void irda_usb_dump_class_desc(struct irda_class_desc *desc)
{
	printk("bLength=%x\n", desc->bLength);
	printk("bDescriptorType=%x\n", desc->bDescriptorType);
	printk("bcdSpecRevision=%x\n", desc->bcdSpecRevision); 
	printk("bmDataSize=%x\n", desc->bmDataSize);
	printk("bmWindowSize=%x\n", desc->bmWindowSize);
	printk("bmMinTurnaroundTime=%d\n", desc->bmMinTurnaroundTime);
	printk("wBaudRate=%x\n", desc->wBaudRate);
	printk("bmAdditionalBOFs=%x\n", desc->bmAdditionalBOFs);
	printk("bIrdaRateSniff=%x\n", desc->bIrdaRateSniff);
	printk("bMaxUnicastList=%x\n", desc->bMaxUnicastList);
}
#endif /* IU_DUMP_CLASS_DESC */

/*------------------------------------------------------------------*/
/*
 * Function irda_usb_find_class_desc(dev, ifnum)
 *
 *    Returns instance of IrDA class descriptor, or NULL if not found
 *
 * The class descriptor is some extra info that IrDA USB devices will
 * offer to us, describing their IrDA characteristics. We will use that in
 * irda_usb_init_qos()
 */
static inline struct irda_class_desc *irda_usb_find_class_desc(struct usb_device *dev, unsigned int ifnum)
{
	struct irda_class_desc *desc;
	int ret;

	desc = kmalloc(sizeof (*desc), GFP_KERNEL);
	if (desc == NULL) 
		return NULL;
	memset(desc, 0, sizeof(*desc));

	/* USB-IrDA class spec 1.0:
	 *	6.1.3: Standard "Get Descriptor" Device Request is not
	 *	       appropriate to retrieve class-specific descriptor
	 *	6.2.5: Class Specific "Get Class Descriptor" Interface Request
	 *	       is mandatory and returns the USB-IrDA class descriptor
	 */

	ret = usb_control_msg(dev, usb_rcvctrlpipe(dev,0),
		IU_REQ_GET_CLASS_DESC,
		USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE,
		0, ifnum, desc, sizeof(*desc), MSECS_TO_JIFFIES(500));
	
	IRDA_DEBUG(1, "%s(), ret=%d\n", __FUNCTION__, ret);
	if (ret < sizeof(*desc)) {
		WARNING("usb-irda: class_descriptor read %s (%d)\n",
			(ret<0) ? "failed" : "too short", ret);
	}
	else if (desc->bDescriptorType != USB_DT_IRDA) {
		WARNING("usb-irda: bad class_descriptor type\n");
	}
	else {
#ifdef IU_DUMP_CLASS_DESC
		irda_usb_dump_class_desc(desc);
#endif	/* IU_DUMP_CLASS_DESC */

		return desc;
	}
	kfree(desc);
	return NULL;
}

/*********************** USB DEVICE CALLBACKS ***********************/
/*
 * Main calls from the USB subsystem.
 * Mostly registering a new irda-usb device and removing it....
 */

/*------------------------------------------------------------------*/
/*
 * This routine is called by the USB subsystem for each new device
 * in the system. We need to check if the device is ours, and in
 * this case start handling it.
 * Note : it might be worth protecting this function by a global
 * spinlock... Or not, because maybe USB already deal with that...
 */
static void *irda_usb_probe(struct usb_device *dev, unsigned int ifnum,
			    const struct usb_device_id *id)
{
	struct irda_usb_cb *self = NULL;
	struct usb_interface_descriptor *interface;
	struct irda_class_desc *irda_desc;
	int ret;
	int i;

	/* Note : the probe make sure to call us only for devices that
	 * matches the list of dongle (top of the file). So, we
	 * don't need to check if the dongle is really ours.
	 * Jean II */

	MESSAGE("IRDA-USB found at address %d, Vendor: %x, Product: %x\n",
		dev->devnum, dev->descriptor.idVendor,
		dev->descriptor.idProduct);

	/* Try to cleanup all instance that have a pending disconnect
	 * In theory, it can't happen any longer.
	 * Jean II */
	for (i = 0; i < NIRUSB; i++) {
		struct irda_usb_cb *irda = &irda_instance[i];
		if((irda->usbdev != NULL) &&
		   (irda->present == 0) &&
		   (irda->netopen == 0)) {
			IRDA_DEBUG(0, "%s(), found a zombie instance !!!\n", __FUNCTION__);
			irda_usb_disconnect(irda->usbdev, (void *) irda);
		}
	}

	/* Find an free instance to handle this new device... */
	self = NULL;
	for (i = 0; i < NIRUSB; i++) {
		if(irda_instance[i].usbdev == NULL) {
			self = &irda_instance[i];
			break;
		}
	}
	if(self == NULL) {
		WARNING("Too many USB IrDA devices !!! (max = %d)\n",
			   NIRUSB);
		return NULL;
	}

	/* Reset the instance */
	self->present = 0;
	self->netopen = 0;

       /* Is this really necessary? */
	if (usb_set_configuration (dev, dev->config[0].bConfigurationValue) < 0) {
		err("set_configuration failed");
		return NULL;
	}

	/* Is this really necessary? */
	/* Note : some driver do hardcode the interface number, some others
	 * specify an alternate, but very few driver do like this.
	 * Jean II */
	ret = usb_set_interface(dev, ifnum, 0);
	IRDA_DEBUG(1, "usb-irda: set interface %d result %d\n", ifnum, ret);
	switch (ret) {
		case USB_ST_NOERROR:		/* 0 */
			break;
		case USB_ST_STALL:		/* -EPIPE = -32 */
			usb_clear_halt(dev, usb_sndctrlpipe(dev, 0));
			IRDA_DEBUG(0, "%s(), Clearing stall on control interface\n", __FUNCTION__);
			break;
		default:
			IRDA_DEBUG(0, "%s(), Unknown error %d\n", __FUNCTION__, ret);
			return NULL;
			break;
	}

	/* Find our endpoints */
	interface = &dev->actconfig->interface[ifnum].altsetting[0];
	if(!irda_usb_parse_endpoints(self, interface->endpoint,
				     interface->bNumEndpoints)) {
		ERROR("%s(), Bogus endpoints...\n", __FUNCTION__);
		return NULL;
	}

	/* Find IrDA class descriptor */
	irda_desc = irda_usb_find_class_desc(dev, ifnum);
	if (irda_desc == NULL)
		return NULL;
	
	self->irda_desc =  irda_desc;	
	self->present = 1;
	self->netopen = 0;
	self->capability = id->driver_info;
	self->usbdev = dev;
	ret = irda_usb_open(self);
	if (ret)
		return NULL;

	return self;
}

/*------------------------------------------------------------------*/
/*
 * The current irda-usb device is removed, the USB layer tell us
 * to shut it down...
 * One of the constraints is that when we exit this function,
 * we cannot use the usb_device no more. Gone. Destroyed. kfree().
 * Most other subsystem allow you to destroy the instance at a time
 * when it's convenient to you, to postpone it to a later date, but
 * not the USB subsystem.
 * So, we must make bloody sure that everything gets deactivated.
 * Jean II
 */
static void irda_usb_disconnect(struct usb_device *dev, void *ptr)
{
	unsigned long flags;
	struct irda_usb_cb *self = (struct irda_usb_cb *) ptr;
	int i;

	IRDA_DEBUG(1, "%s()\n", __FUNCTION__);

	/* Make sure that the Tx path is not executing. - Jean II */
	spin_lock_irqsave(&self->lock, flags);

	/* Oups ! We are not there any more.
	 * This will stop/desactivate the Tx path. - Jean II */
	self->present = 0;

	/* We need to have irq enabled to unlink the URBs. That's OK,
	 * at this point the Tx path is gone - Jean II */
	spin_unlock_irqrestore(&self->lock, flags);

	/* Hum... Check if networking is still active (avoid races) */
	if((self->netopen) || (self->irlap)) {
		/* Accept no more transmissions */
		/*netif_device_detach(self->netdev);*/
		netif_stop_queue(self->netdev);
		/* Stop all the receive URBs */
		for (i = 0; i < IU_MAX_RX_URBS; i++)
			usb_unlink_urb(&(self->rx_urb[i]));
		/* Cancel Tx and speed URB.
		 * Toggle flags to make sure it's synchronous. */
		self->tx_urb.transfer_flags &= ~USB_ASYNC_UNLINK;
		usb_unlink_urb(&(self->tx_urb));
		self->speed_urb.transfer_flags &= ~USB_ASYNC_UNLINK;
		usb_unlink_urb(&(self->speed_urb));
	}

	/* Cleanup the device stuff */
	irda_usb_close(self);
	/* No longer attached to USB bus */
	self->usbdev = NULL;
	IRDA_DEBUG(0, "%s(), USB IrDA Disconnected\n", __FUNCTION__);
}

/*------------------------------------------------------------------*/
/*
 * USB device callbacks
 */
static struct usb_driver irda_driver = {
	name:		"irda-usb",
	probe:		irda_usb_probe,
	disconnect:	irda_usb_disconnect,
	id_table:	dongles,
};

/************************* MODULE CALLBACKS *************************/
/*
 * Deal with module insertion/removal
 * Mostly tell USB about our existence
 */

/*------------------------------------------------------------------*/
/*
 * Module insertion
 */
int __init usb_irda_init(void)
{
	if (usb_register(&irda_driver) < 0)
		return -1;

	MESSAGE("USB IrDA support registered\n");
	return 0;
}
module_init(usb_irda_init);

/*------------------------------------------------------------------*/
/*
 * Module removal
 */
void __exit usb_irda_cleanup(void)
{
	struct irda_usb_cb *irda = NULL;
	int	i;

	/* Find zombie instances and kill them...
	 * In theory, it can't happen any longer. Jean II */
	for (i = 0; i < NIRUSB; i++) {
		irda = &irda_instance[i];
		/* If the Device is zombie */
		if((irda->usbdev != NULL) && (irda->present == 0)) {
			IRDA_DEBUG(0, "%s(), disconnect zombie now !\n", __FUNCTION__);
			irda_usb_disconnect(irda->usbdev, (void *) irda);
		}
	}

	/* Deregister the driver and remove all pending instances */
	usb_deregister(&irda_driver);
}
module_exit(usb_irda_cleanup);

/*------------------------------------------------------------------*/
/*
 * Module parameters
 */
MODULE_PARM(qos_mtt_bits, "i");
MODULE_PARM_DESC(qos_mtt_bits, "Minimum Turn Time");
MODULE_AUTHOR("Roman Weissgaerber <weissg@vienna.at>, Dag Brattli <dag@brattli.net> and Jean Tourrilhes <jt@hpl.hp.com>");
MODULE_DESCRIPTION("IrDA-USB Dongle Driver"); 
MODULE_LICENSE("GPL");
