Merge branch 'lro'

[linux-2.6] / drivers / net / irda / irda-usb.c

/*****************************************************************************
 *
 * 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 2.5.20, 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-hcd  (For Intel/Via USB controllers)
 *      o uhci-hcd      (Alternate/JE driver for Intel/Via USB controllers)
 *      o ohci-hcd      (For other USB controllers)
 *
 * This driver has NOT been tested with the following drivers :
 *      o ehci-hcd      (USB 2.0 controllers)
 *
 * Note that all HCD drivers do URB_ZERO_PACKET and timeout properly,
 * so we don't have to worry about that anymore.
 * One common problem is the failure to set the address on the dongle,
 * but this happens before the driver gets loaded...
 *
 * Jean II
 */

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

#include <linux/module.h>
#include <linux/moduleparam.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 "irda-usb.h"

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

static int qos_mtt_bits = 0;

/* 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 },
        /* Look like ACTiSYS, Report : IBM Corp., IBM UltraPort IrDA */
        { USB_DEVICE(0x4428, 0x012), .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 designed
 * using the "USB-IrDA specification" (yes, there exist such a thing), and
 * therefore not supported by this driver (don't add them above).
 * There is a Linux driver, stir4200, that support those USB devices.
 * Jean II
 */

MODULE_DEVICE_TABLE(usb, dongles);

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

static struct irda_class_desc *irda_usb_find_class_desc(struct usb_interface *intf);
static void irda_usb_disconnect(struct usb_interface *intf);
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 void irda_usb_close(struct irda_usb_cb *self);
static void speed_bulk_callback(struct urb *urb, struct pt_regs *regs);
static void write_bulk_callback(struct urb *urb, struct pt_regs *regs);
static void irda_usb_receive(struct urb *urb, struct pt_regs *regs);
static void irda_usb_rx_defer_expired(unsigned long data);
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 ugliness...
 */

/*------------------------------------------------------------------*/
/*
 * 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;
                /* We will do ` self->new_speed = -1; ' in the completion
                 * handler just in case the current URB fail - Jean II */

                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;
                /* We will do ` self->new_xbofs = -1; ' in the completion
                 * handler just in case the current URB fail - Jean II */

                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;
        struct urb *urb;
        int ret;

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

        /* Grab the speed URB */
        urb = self->speed_urb;
        if (urb->status != 0) {
                IRDA_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 */
        usb_fill_bulk_urb(urb, self->usbdev,
                      usb_sndbulkpipe(self->usbdev, self->bulk_out_ep),
                      frame, IRDA_USB_SPEED_MTU,
                      speed_bulk_callback, self);
        urb->transfer_buffer_length = USB_IRDA_HEADER;
        urb->transfer_flags = 0;

        /* Irq disabled -> GFP_ATOMIC */
        if ((ret = usb_submit_urb(urb, GFP_ATOMIC))) {
                IRDA_WARNING("%s(), failed Speed URB\n", __FUNCTION__);
        }
}

/*------------------------------------------------------------------*/
/*
 * Speed URB callback
 * Now, we can only get called for the speed URB.
 */
static void speed_bulk_callback(struct urb *urb, struct pt_regs *regs)
{
        struct irda_usb_cb *self = urb->context;
        
        IRDA_DEBUG(2, "%s()\n", __FUNCTION__);

        /* We should always have a context */
        IRDA_ASSERT(self != NULL, return;);
        /* We should always be called for the speed URB */
        IRDA_ASSERT(urb == self->speed_urb, return;);

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

        /* New speed and xbof is now commited in hardware */
        self->new_speed = -1;
        self->new_xbofs = -1;

        /* Allow the stack to send more packets */
        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 *urb = self->tx_urb;
        unsigned long flags;
        s32 speed;
        s16 xbofs;
        int res, mtt;
        int     err = 1;        /* Failed */

        IRDA_DEBUG(4, "%s() on %s\n", __FUNCTION__, netdev->name);

        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->present) {
                IRDA_DEBUG(0, "%s(), Device is gone...\n", __FUNCTION__);
                goto drop;
        }

        /* 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 */
                        err = 0;        /* No error */
                        goto drop;
                }
        }

        if (urb->status != 0) {
                IRDA_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)) {
                        IRDA_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;

        usb_fill_bulk_urb(urb, self->usbdev, 
                      usb_sndbulkpipe(self->usbdev, self->bulk_out_ep),
                      skb->data, IRDA_SKB_MAX_MTU,
                      write_bulk_callback, skb);
        urb->transfer_buffer_length = skb->len;
        /* This flag (URB_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 */
        urb->transfer_flags = URB_ZERO_PACKET;

        /* 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 the usec counter did wraparound, the diff will
                         * go negative (tv_usec is a long), so we need to
                         * correct it by one second. Jean II */
                        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 - Irq disabled -> GFP_ATOMIC */
        if ((res = usb_submit_urb(urb, GFP_ATOMIC))) {
                IRDA_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 err;             /* Usually 1 */
}

/*------------------------------------------------------------------*/
/*
 * Note : this function will be called only for tx_urb...
 */
static void write_bulk_callback(struct urb *urb, struct pt_regs *regs)
{
        unsigned long flags;
        struct sk_buff *skb = urb->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 */
        IRDA_ASSERT(self != NULL, return;);
        /* We should always be called for the speed URB */
        IRDA_ASSERT(urb == self->tx_urb, return;);

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

        /* Check for timeout and other USB nasties */
        if (urb->status != 0) {
                /* I get a lot of -ECONNABORTED = -103 here - Jean II */
                IRDA_DEBUG(0, "%s(), URB complete status %d, transfer_flags 0x%04X\n", __FUNCTION__, urb->status, urb->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 */
        //urb->status = 0; -> 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 changes to speed or xbofs is pending... */
        if ((self->new_speed != -1) || (self->new_xbofs != -1)) {
                if ((self->new_speed != self->speed) ||
                    (self->new_xbofs != self->xbofs)) {
                        /* We haven't changed speed yet (because of
                         * IUC_SPEED_BUG), so do it now - Jean II */
                        IRDA_DEBUG(1, "%s(), Changing speed now...\n", __FUNCTION__);
                        irda_usb_change_speed_xbofs(self);
                } else {
                        /* New speed and xbof is now commited in hardware */
                        self->new_speed = -1;
                        self->new_xbofs = -1;
                        /* Done, waiting for next packet */
                        netif_wake_queue(self->netdev);
                }
        } 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 *urb;
        int     done = 0;       /* If we have made any progress */

        IRDA_DEBUG(0, "%s(), Network layer thinks we timed out!\n", __FUNCTION__);
        IRDA_ASSERT(self != NULL, return;);

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

        /* self->present *MUST* be read under spinlock */
        if (!self->present) {
                IRDA_WARNING("%s(), device not present!\n", __FUNCTION__);
                netif_stop_queue(netdev);
                spin_unlock_irqrestore(&self->lock, flags);
                return;
        }

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

                switch (urb->status) {
                case -EINPROGRESS:
                        usb_unlink_urb(urb);
                        /* 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 */
                        urb->status = 0;
                        netif_wake_queue(self->netdev);
                        done = 1;
                        break;
                }
        }

        /* Check Tx URB */
        urb = self->tx_urb;
        if (urb->status != 0) {
                struct sk_buff *skb = urb->context;

                IRDA_DEBUG(0, "%s: Tx timed out, urb->status=%d, urb->transfer_flags=0x%04X\n", netdev->name, urb->status, urb->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 (urb->status) {
                case -EINPROGRESS:
                        usb_unlink_urb(urb);
                        /* Note : above will  *NOT* call netif_wake_queue()
                         * in completion handler, because urb->status will
                         * be -ENOENT. We will fix that at the next watchdog,
                         * leaving more time to USB to recover...
                         * 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);
                                urb->context = NULL;
                        }
                        urb->status = 0;
                        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
 *
 * Note : don't read the above as what we are currently doing, but as
 * something we could do with KC dongle. Also don't forget that the
 * interrupt pipe is not part of the original standard, so this would
 * need to be optional...
 * Jean II
 */

/*------------------------------------------------------------------*/
/*
 * Submit a Rx URB to the USB layer to handle reception of a frame
 * Mostly called by the completion callback of the previous URB.
 *
 * Jean II
 */
static void irda_usb_submit(struct irda_usb_cb *self, struct sk_buff *skb, struct urb *urb)
{
        struct irda_skb_cb *cb;
        int ret;

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

        /* This should never happen */
        IRDA_ASSERT(skb != NULL, return;);
        IRDA_ASSERT(urb != NULL, return;);

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

        /* Reinitialize URB */
        usb_fill_bulk_urb(urb, self->usbdev, 
                      usb_rcvbulkpipe(self->usbdev, self->bulk_in_ep), 
                      skb->data, IRDA_SKB_MAX_MTU,
                      irda_usb_receive, skb);
        urb->status = 0;

        /* Can be called from irda_usb_receive (irq handler) -> GFP_ATOMIC */
        ret = usb_submit_urb(urb, GFP_ATOMIC);
        if (ret) {
                /* If this ever happen, we are in deep s***.
                 * Basically, the Rx path will stop... */
                IRDA_WARNING("%s(), Failed to submit Rx URB %d\n",
                             __FUNCTION__, ret);
        }
}

/*------------------------------------------------------------------*/
/*
 * Function irda_usb_receive(urb)
 *
 *     Called by the USB subsystem when a frame has been received
 *
 */
static void irda_usb_receive(struct urb *urb, struct pt_regs *regs)
{
        struct sk_buff *skb = (struct sk_buff *) urb->context;
        struct irda_usb_cb *self; 
        struct irda_skb_cb *cb;
        struct sk_buff *newskb;
        struct sk_buff *dataskb;
        struct urb *next_urb;
        int             docopy;

        IRDA_DEBUG(2, "%s(), len=%d\n", __FUNCTION__, urb->actual_length);
        
        /* Find ourselves */
        cb = (struct irda_skb_cb *) skb->cb;
        IRDA_ASSERT(cb != NULL, return;);
        self = (struct irda_usb_cb *) cb->context;
        IRDA_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 (urb->status != 0) {
                switch (urb->status) {
                case -EILSEQ:
                        self->stats.rx_crc_errors++;    
                        /* Also precursor to a hot-unplug on UHCI. */
                        /* Fallthrough... */
                case -ECONNRESET:               /* -104 */
                        /* Random error, if I remember correctly */
                        /* 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 */
                case -ESHUTDOWN:                /* -108 */
                        /* That's usually a hot-unplug. Submit will fail... */
                case -ETIMEDOUT:                /* -110 */
                        /* Usually precursor to a hot-unplug on OHCI. */
                default:
                        self->stats.rx_errors++;
                        IRDA_DEBUG(0, "%s(), RX status %d, transfer_flags 0x%04X \n", __FUNCTION__, urb->status, urb->transfer_flags);
                        break;
                }
                /* If we received an error, we don't want to resubmit the
                 * Rx URB straight away but to give the USB layer a little
                 * bit of breathing room.
                 * We are in the USB thread context, therefore there is a
                 * danger of recursion (new URB we submit fails, we come
                 * back here).
                 * With recent USB stack (2.6.15+), I'm seeing that on
                 * hot unplug of the dongle...
                 * Lowest effective timer is 10ms...
                 * Jean II */
                self->rx_defer_timer.function = &irda_usb_rx_defer_expired;
                self->rx_defer_timer.data = (unsigned long) urb;
                mod_timer(&self->rx_defer_timer, jiffies + (10 * HZ / 1000));
                return;
        }
        
        /* Check for empty frames */
        if (urb->actual_length <= USB_IRDA_HEADER) {
                IRDA_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);

        /* Check if we need to copy the data to a new skb or not.
         * For most frames, we use ZeroCopy and pass the already
         * allocated skb up the stack.
         * If the frame is small, it is more efficient to copy it
         * to save memory (copy will be fast anyway - that's
         * called Rx-copy-break). Jean II */
        docopy = (urb->actual_length < IRDA_RX_COPY_THRESHOLD);

        /* Allocate a new skb */
        newskb = dev_alloc_skb(docopy ? urb->actual_length : IRDA_SKB_MAX_MTU);
        if (!newskb)  {
                self->stats.rx_dropped++;
                /* We could deliver the current skb, but this would stall
                 * the Rx path. Better drop the packet... Jean II */
                goto done;  
        }

        /* Make sure IP header get aligned (IrDA header is 5 bytes) */
        /* But IrDA-USB header is 1 byte. Jean II */
        //skb_reserve(newskb, USB_IRDA_HEADER - 1);

        if(docopy) {
                /* Copy packet, so we can recycle the original */
                memcpy(newskb->data, skb->data, urb->actual_length);
                /* Deliver this new skb */
                dataskb = newskb;
                /* And hook the old skb to the URB
                 * Note : we don't need to "clean up" the old skb,
                 * as we never touched it. Jean II */
        } else {
                /* We are using ZeroCopy. Deliver old skb */
                dataskb = skb;
                /* And hook the new skb to the URB */
                skb = newskb;
        }

        /* Set proper length on skb & remove USB-IrDA header */
        skb_put(dataskb, urb->actual_length);
        skb_pull(dataskb, USB_IRDA_HEADER);

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

        /* Keep stats up to date */
        self->stats.rx_bytes += dataskb->len;
        self->stats.rx_packets++;
        self->netdev->last_rx = jiffies;

done:
        /* Note : at this point, the URB we've just received (urb)
         * 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. I don't think it would buy us anything as
         * we are running in the USB thread context. Jean II */
        next_urb = self->idle_rx_urb;

        /* Recycle Rx URB : Now, the idle URB is the present one */
        urb->context = NULL;
        self->idle_rx_urb = urb;

        /* Submit the idle URB to replace the URB we've just received.
         * Do it last to avoid race conditions... Jean II */
        irda_usb_submit(self, skb, next_urb);
}

/*------------------------------------------------------------------*/
/*
 * In case of errors, we want the USB layer to have time to recover.
 * Now, it is time to resubmit ouur Rx URB...
 */
static void irda_usb_rx_defer_expired(unsigned long data)
{
        struct urb *urb = (struct urb *) data;
        struct sk_buff *skb = (struct sk_buff *) urb->context;
        struct irda_usb_cb *self; 
        struct irda_skb_cb *cb;
        struct urb *next_urb;

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

        /* Find ourselves */
        cb = (struct irda_skb_cb *) skb->cb;
        IRDA_ASSERT(cb != NULL, return;);
        self = (struct irda_usb_cb *) cb->context;
        IRDA_ASSERT(self != NULL, return;);

        /* Same stuff as when Rx is done, see above... */
        next_urb = self->idle_rx_urb;
        urb->context = NULL;
        self->idle_rx_urb = urb;
        irda_usb_submit(self, skb, next_urb);
}

/*------------------------------------------------------------------*/
/*
 * 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...
 */


/*------------------------------------------------------------------*/
/*
 * 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__);

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

        /* Can only open the device if it's there */
        if(!self->present) {
                IRDA_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);
        IRDA_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++) {
                struct sk_buff *skb = dev_alloc_skb(IRDA_SKB_MAX_MTU);
                if (!skb) {
                        /* If this ever happen, we are in deep s***.
                         * Basically, we can't start the Rx path... */
                        IRDA_WARNING("%s(), Failed to allocate Rx skb\n",
                                     __FUNCTION__);
                        return -1;
                }
                //skb_reserve(newskb, USB_IRDA_HEADER - 1);
                irda_usb_submit(self, skb, self->rx_urb[i]);
        }

        /* Ready to play !!! */
        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__);

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

        /* Kill defered Rx URB */
        del_timer(&self->rx_defer_timer);

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

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

        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;

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

        /* See spec section 7.2 for meaning.
         * Values are little endian (as most USB stuff), the IrDA stack
         * use it in native order (see parameters.c). - Jean II */
        self->qos.baud_rate.bits       = le16_to_cpu(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        &= 0x00ff;
        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);
}

/*------------------------------------------------------------------*/
/*
 * 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 = self->netdev;

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

        irda_usb_init_qos(self);

        /* Override the network functions we need to use */
        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;

        return register_netdev(netdev);
}

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

        /* Remove netdevice */
        unregister_netdev(self->netdev);

        /* Remove the speed buffer */
        kfree(self->speed_buff);
        self->speed_buff = NULL;
}

/********************** 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_host_endpoint *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].desc.bEndpointAddress & USB_ENDPOINT_NUMBER_MASK;
                dir = endpoint[i].desc.bEndpointAddress & USB_ENDPOINT_DIR_MASK;
                attr = endpoint[i].desc.bmAttributes;
                psize = le16_to_cpu(endpoint[i].desc.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 {
                                IRDA_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 */
        IRDA_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)
{
        /* Values are little endian */
        printk("bLength=%x\n", desc->bLength);
        printk("bDescriptorType=%x\n", desc->bDescriptorType);
        printk("bcdSpecRevision=%x\n", le16_to_cpu(desc->bcdSpecRevision)); 
        printk("bmDataSize=%x\n", desc->bmDataSize);
        printk("bmWindowSize=%x\n", desc->bmWindowSize);
        printk("bmMinTurnaroundTime=%d\n", desc->bmMinTurnaroundTime);
        printk("wBaudRate=%x\n", le16_to_cpu(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(intf)
 *
 *    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_interface *intf)
{
        struct usb_device *dev = interface_to_usbdev (intf);
        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, intf->altsetting->desc.bInterfaceNumber, desc,
                sizeof(*desc), 500);
        
        IRDA_DEBUG(1, "%s(), ret=%d\n", __FUNCTION__, ret);
        if (ret < sizeof(*desc)) {
                IRDA_WARNING("usb-irda: class_descriptor read %s (%d)\n",
                             (ret<0) ? "failed" : "too short", ret);
        }
        else if (desc->bDescriptorType != USB_DT_IRDA) {
                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.
 * The USB layer protect us from reentrancy (via BKL), so we don't need
 * to spinlock in there... Jean II
 */
static int irda_usb_probe(struct usb_interface *intf,
                          const struct usb_device_id *id)
{
        struct net_device *net;
        struct usb_device *dev = interface_to_usbdev(intf);
        struct irda_usb_cb *self = NULL;
        struct usb_host_interface *interface;
        struct irda_class_desc *irda_desc;
        int ret = -ENOMEM;
        int i;          /* Driver instance index / Rx URB index */

        /* 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 */

        IRDA_MESSAGE("IRDA-USB found at address %d, Vendor: %x, Product: %x\n",
                     dev->devnum, le16_to_cpu(dev->descriptor.idVendor),
                     le16_to_cpu(dev->descriptor.idProduct));

        net = alloc_irdadev(sizeof(*self));
        if (!net) 
                goto err_out;

        SET_MODULE_OWNER(net);
        SET_NETDEV_DEV(net, &intf->dev);
        self = net->priv;
        self->netdev = net;
        spin_lock_init(&self->lock);
        init_timer(&self->rx_defer_timer);

        /* Create all of the needed urbs */
        for (i = 0; i < IU_MAX_RX_URBS; i++) {
                self->rx_urb[i] = usb_alloc_urb(0, GFP_KERNEL);
                if (!self->rx_urb[i]) {
                        goto err_out_1;
                }
        }
        self->tx_urb = usb_alloc_urb(0, GFP_KERNEL);
        if (!self->tx_urb) {
                goto err_out_1;
        }
        self->speed_urb = usb_alloc_urb(0, GFP_KERNEL);
        if (!self->speed_urb) {
                goto err_out_2;
        }

        /* Is this really necessary? (no, except maybe for broken devices) */
        if (usb_reset_configuration (dev) < 0) {
                err("reset_configuration failed");
                ret = -EIO;
                goto err_out_3;
        }

        /* 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, intf->altsetting->desc.bInterfaceNumber, 0);
        IRDA_DEBUG(1, "usb-irda: set interface %d result %d\n", intf->altsetting->desc.bInterfaceNumber, ret);
        switch (ret) {
                case 0:
                        break;
                case -EPIPE:            /* -EPIPE = -32 */
                        /* Martin Diehl says if we get a -EPIPE we should
                         * be fine and we don't need to do a usb_clear_halt().
                         * - Jean II */
                        IRDA_DEBUG(0, "%s(), Received -EPIPE, ignoring...\n", __FUNCTION__);
                        break;
                default:
                        IRDA_DEBUG(0, "%s(), Unknown error %d\n", __FUNCTION__, ret);
                        ret = -EIO;
                        goto err_out_3;
        }

        /* Find our endpoints */
        interface = intf->cur_altsetting;
        if(!irda_usb_parse_endpoints(self, interface->endpoint,
                                     interface->desc.bNumEndpoints)) {
                IRDA_ERROR("%s(), Bogus endpoints...\n", __FUNCTION__);
                ret = -EIO;
                goto err_out_3;
        }

        /* Find IrDA class descriptor */
        irda_desc = irda_usb_find_class_desc(intf);
        ret = -ENODEV;
        if (irda_desc == NULL)
                goto err_out_3;

        self->irda_desc =  irda_desc;
        self->present = 1;
        self->netopen = 0;
        self->capability = id->driver_info;
        self->usbdev = dev;
        self->usbintf = intf;

        /* 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) 
                goto err_out_3;

        memset(self->speed_buff, 0, IRDA_USB_SPEED_MTU);

        ret = irda_usb_open(self);
        if (ret) 
                goto err_out_4;

        IRDA_MESSAGE("IrDA: Registered device %s\n", net->name);
        usb_set_intfdata(intf, self);
        return 0;

err_out_4:
        kfree(self->speed_buff);
err_out_3:
        /* Free all urbs that we may have created */
        usb_free_urb(self->speed_urb);
err_out_2:
        usb_free_urb(self->tx_urb);
err_out_1:
        for (i = 0; i < IU_MAX_RX_URBS; i++) {
                if (self->rx_urb[i])
                        usb_free_urb(self->rx_urb[i]);
        }
        free_netdev(net);
err_out:
        return ret;
}

/*------------------------------------------------------------------*/
/*
 * 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_interface *intf)
{
        unsigned long flags;
        struct irda_usb_cb *self = usb_get_intfdata(intf);
        int i;

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

        usb_set_intfdata(intf, NULL);
        if (!self)
                return;

        /* 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;

        /* Kill defered Rx URB */
        del_timer(&self->rx_defer_timer);

        /* 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. Must be synchronous. */
                for (i = 0; i < IU_MAX_RX_URBS; i++)
                        usb_kill_urb(self->rx_urb[i]);
                /* Cancel Tx and speed URB.
                 * Make sure it's synchronous to avoid races. */
                usb_kill_urb(self->tx_urb);
                usb_kill_urb(self->speed_urb);
        }

        /* Cleanup the device stuff */
        irda_usb_close(self);
        /* No longer attached to USB bus */
        self->usbdev = NULL;
        self->usbintf = NULL;

        /* Clean up our urbs */
        for (i = 0; i < IU_MAX_RX_URBS; i++)
                usb_free_urb(self->rx_urb[i]);
        /* Clean up Tx and speed URB */
        usb_free_urb(self->tx_urb);
        usb_free_urb(self->speed_urb);

        /* Free self and network device */
        free_netdev(self->netdev);
        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
 */
static int __init usb_irda_init(void)
{
        int     ret;

        ret = usb_register(&irda_driver);
        if (ret < 0)
                return ret;

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

/*------------------------------------------------------------------*/
/*
 * Module removal
 */
static void __exit usb_irda_cleanup(void)
{
        /* Deregister the driver and remove all pending instances */
        usb_deregister(&irda_driver);
}
module_exit(usb_irda_cleanup);

/*------------------------------------------------------------------*/
/*
 * Module parameters
 */
module_param(qos_mtt_bits, int, 0);
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");