/******************************************************************************
 *  speedtouch.c  -  Alcatel SpeedTouch USB xDSL modem driver
 *
 *  Copyright (C) 2001, Alcatel
 *  Copyright (C) 2003, Duncan Sands
 *
 *  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., 59
 *  Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 *
 ******************************************************************************/

/*
 *  Written by Johan Verrept, maintained by Duncan Sands (duncan.sands@free.fr)
 *
 *  1.7+:       - See the check-in logs
 *
 *  1.6:        - No longer opens a connection if the firmware is not loaded
 *              - Added support for the speedtouch 330
 *              - Removed the limit on the number of devices
 *              - Module now autoloads on device plugin
 *              - Merged relevant parts of sarlib
 *              - Replaced the kernel thread with a tasklet
 *              - New packet transmission code
 *              - Changed proc file contents
 *              - Fixed all known SMP races
 *              - Many fixes and cleanups
 *              - Various fixes by Oliver Neukum (oliver@neukum.name)
 *
 *  1.5A:       - Backport of version for inclusion in 2.5 series kernel
 *              - Modifications by Richard Purdie (rpurdie@rpsys.net)
 *              - made compatible with kernel 2.5.6 onwards by changing
 *              udsl_usb_send_data_context->urb to a pointer and adding code
 *              to alloc and free it
 *              - remove_wait_queue() added to udsl_atm_processqueue_thread()
 *
 *  1.5:        - fixed memory leak when atmsar_decode_aal5 returned NULL.
 *              (reported by stephen.robinson@zen.co.uk)
 *
 *  1.4:        - changed the spin_lock() under interrupt to spin_lock_irqsave()
 *              - unlink all active send urbs of a vcc that is being closed.
 *
 *  1.3.1:      - added the version number
 *
 *  1.3:        - Added multiple send urb support
 *              - fixed memory leak and vcc->tx_inuse starvation bug
 *                when not enough memory left in vcc.
 *
 *  1.2:        - Fixed race condition in udsl_usb_send_data()
 *  1.1:        - Turned off packet debugging
 *
 */

#include <asm/semaphore.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/timer.h>
#include <linux/errno.h>
#include <linux/proc_fs.h>
#include <linux/slab.h>
#include <linux/list.h>
#include <asm/uaccess.h>
#include <linux/smp_lock.h>
#include <linux/interrupt.h>
#include <linux/atm.h>
#include <linux/atmdev.h>
#include <linux/crc32.h>
#include <linux/init.h>

/*
#define DEBUG
#define VERBOSE_DEBUG
*/

#if !defined (DEBUG) && defined (CONFIG_USB_DEBUG)
#       define DEBUG
#endif

#include <linux/usb.h>

#ifdef DEBUG
#define DEBUG_ON(x)     BUG_ON(x)
#else
#define DEBUG_ON(x)     do { if (x); } while (0)
#endif

#ifdef VERBOSE_DEBUG
static int udsl_print_packet (const unsigned char *data, int len);
#define PACKETDEBUG(arg...)     udsl_print_packet (arg)
#define vdbg(arg...)            dbg (arg)
#else
#define PACKETDEBUG(arg...)
#define vdbg(arg...)
#endif

#define DRIVER_AUTHOR   "Johan Verrept, Duncan Sands <duncan.sands@free.fr>"
#define DRIVER_VERSION  "1.8"
#define DRIVER_DESC     "Alcatel SpeedTouch USB driver version " DRIVER_VERSION

static const char udsl_driver_name [] = "speedtch";

#define SPEEDTOUCH_VENDORID             0x06b9
#define SPEEDTOUCH_PRODUCTID            0x4061

#define UDSL_MAX_RCV_URBS               4
#define UDSL_MAX_SND_URBS               4
#define UDSL_MAX_RCV_BUFS               8
#define UDSL_MAX_SND_BUFS               8
#define UDSL_MAX_RCV_BUF_SIZE           1024 /* ATM cells */
#define UDSL_MAX_SND_BUF_SIZE           1024 /* ATM cells */
#define UDSL_DEFAULT_RCV_URBS           1
#define UDSL_DEFAULT_SND_URBS           1
#define UDSL_DEFAULT_RCV_BUFS           2
#define UDSL_DEFAULT_SND_BUFS           2
#define UDSL_DEFAULT_RCV_BUF_SIZE       64 /* ATM cells */
#define UDSL_DEFAULT_SND_BUF_SIZE       64 /* ATM cells */

static unsigned int num_rcv_urbs = UDSL_DEFAULT_RCV_URBS;
static unsigned int num_snd_urbs = UDSL_DEFAULT_SND_URBS;
static unsigned int num_rcv_bufs = UDSL_DEFAULT_RCV_BUFS;
static unsigned int num_snd_bufs = UDSL_DEFAULT_SND_BUFS;
static unsigned int rcv_buf_size = UDSL_DEFAULT_RCV_BUF_SIZE;
static unsigned int snd_buf_size = UDSL_DEFAULT_SND_BUF_SIZE;

MODULE_PARM (num_rcv_urbs, "i");
MODULE_PARM_DESC (num_rcv_urbs, "Number of urbs used for reception (range: 0-" __MODULE_STRING (UDSL_MAX_RCV_URBS) ", default: " __MODULE_STRING (UDSL_DEFAULT_RCV_URBS) ")");

MODULE_PARM (num_snd_urbs, "i");
MODULE_PARM_DESC (num_snd_urbs, "Number of urbs used for transmission (range: 0-" __MODULE_STRING (UDSL_MAX_SND_URBS) ", default: " __MODULE_STRING (UDSL_DEFAULT_SND_URBS) ")");

MODULE_PARM (num_rcv_bufs, "i");
MODULE_PARM_DESC (num_rcv_bufs, "Number of buffers used for reception (range: 0-" __MODULE_STRING (UDSL_MAX_RCV_BUFS) ", default: " __MODULE_STRING (UDSL_DEFAULT_RCV_BUFS) ")");

MODULE_PARM (num_snd_bufs, "i");
MODULE_PARM_DESC (num_snd_bufs, "Number of buffers used for transmission (range: 0-" __MODULE_STRING (UDSL_MAX_SND_BUFS) ", default: " __MODULE_STRING (UDSL_DEFAULT_SND_BUFS) ")");

MODULE_PARM (rcv_buf_size, "i");
MODULE_PARM_DESC (rcv_buf_size, "Size of the buffers used for reception (range: 0-" __MODULE_STRING (UDSL_MAX_RCV_BUF_SIZE) ", default: " __MODULE_STRING (UDSL_DEFAULT_RCV_BUF_SIZE) ")");

MODULE_PARM (snd_buf_size, "i");
MODULE_PARM_DESC (snd_buf_size, "Size of the buffers used for transmission (range: 0-" __MODULE_STRING (UDSL_MAX_SND_BUF_SIZE) ", default: " __MODULE_STRING (UDSL_DEFAULT_SND_BUF_SIZE) ")");

#define UDSL_IOCTL_LINE_UP              1
#define UDSL_IOCTL_LINE_DOWN            2

#define UDSL_ENDPOINT_DATA_OUT          0x07
#define UDSL_ENDPOINT_DATA_IN           0x87

#define ATM_CELL_HEADER                 (ATM_CELL_SIZE - ATM_CELL_PAYLOAD)
#define UDSL_NUM_CELLS(x)               (((x) + ATM_AAL5_TRAILER + ATM_CELL_PAYLOAD - 1) / ATM_CELL_PAYLOAD)

#define hex2int(c) ( (c >= '0') && (c <= '9') ? (c - '0') : ((c & 0xf) + 9) )

static struct usb_device_id udsl_usb_ids [] = {
        { USB_DEVICE (SPEEDTOUCH_VENDORID, SPEEDTOUCH_PRODUCTID) },
        { }
};

MODULE_DEVICE_TABLE (usb, udsl_usb_ids);

/* receive */

struct udsl_receive_buffer {
        struct list_head list;
        unsigned char *base;
        unsigned int filled_cells;
};

struct udsl_receiver {
        struct list_head list;
        struct udsl_receive_buffer *buffer;
        struct urb *urb;
        struct udsl_instance_data *instance;
};

struct udsl_vcc_data {
        /* vpi/vci lookup */
        struct list_head list;
        short vpi;
        int vci;
        struct atm_vcc *vcc;

        /* raw cell reassembly */
        struct sk_buff *sarb;
};

/* send */

struct udsl_send_buffer {
        struct list_head list;
        unsigned char *base;
        unsigned char *free_start;
        unsigned int free_cells;
};

struct udsl_sender {
        struct list_head list;
        struct udsl_send_buffer *buffer;
        struct urb *urb;
        struct udsl_instance_data *instance;
};

struct udsl_control {
        struct atm_skb_data atm_data;
        unsigned int num_cells;
        unsigned int num_entire;
        unsigned int pdu_padding;
        unsigned char cell_header [ATM_CELL_HEADER];
        unsigned char aal5_trailer [ATM_AAL5_TRAILER];
};

#define UDSL_SKB(x)             ((struct udsl_control *)(x)->cb)

/* main driver data */

struct udsl_instance_data {
        struct semaphore serialize;

        /* USB device part */
        struct usb_device *usb_dev;
        char description [64];
        int firmware_loaded;

        /* ATM device part */
        struct atm_dev *atm_dev;
        struct list_head vcc_list;

        /* receive */
        struct udsl_receiver receivers [UDSL_MAX_RCV_URBS];
        struct udsl_receive_buffer receive_buffers [UDSL_MAX_RCV_BUFS];

        spinlock_t receive_lock;
        struct list_head spare_receivers;
        struct list_head filled_receive_buffers;

        struct tasklet_struct receive_tasklet;
        struct list_head spare_receive_buffers;

        /* send */
        struct udsl_sender senders [UDSL_MAX_SND_URBS];
        struct udsl_send_buffer send_buffers [UDSL_MAX_SND_BUFS];

        struct sk_buff_head sndqueue;

        spinlock_t send_lock;
        struct list_head spare_senders;
        struct list_head spare_send_buffers;

        struct tasklet_struct send_tasklet;
        struct sk_buff *current_skb;                    /* being emptied */
        struct udsl_send_buffer *current_buffer;        /* being filled */
        struct list_head filled_send_buffers;
};

/* ATM */

static void udsl_atm_dev_close (struct atm_dev *dev);
static int udsl_atm_open (struct atm_vcc *vcc, short vpi, int vci);
static void udsl_atm_close (struct atm_vcc *vcc);
static int udsl_atm_ioctl (struct atm_dev *dev, unsigned int cmd, void *arg);
static int udsl_atm_send (struct atm_vcc *vcc, struct sk_buff *skb);
static int udsl_atm_proc_read (struct atm_dev *atm_dev, loff_t *pos, char *page);

static struct atmdev_ops udsl_atm_devops = {
        dev_close:      udsl_atm_dev_close,
        open:           udsl_atm_open,
        close:          udsl_atm_close,
        ioctl:          udsl_atm_ioctl,
        send:           udsl_atm_send,
        proc_read:      udsl_atm_proc_read,
        owner:          THIS_MODULE,
};

/* USB */

static void *udsl_usb_probe (struct usb_device *dev, unsigned int ifnum, const struct usb_device_id *id);
static void udsl_usb_disconnect (struct usb_device *dev, void *ptr);
static int udsl_usb_ioctl (struct usb_device *hub, unsigned int code, void *user_data);

static struct usb_driver udsl_usb_driver = {
        owner:          THIS_MODULE,
        name:           udsl_driver_name,
        probe:          udsl_usb_probe,
        disconnect:     udsl_usb_disconnect,
        ioctl:          udsl_usb_ioctl,
        id_table:       udsl_usb_ids,
};


/***********
**  misc  **
***********/

static inline void udsl_pop (struct atm_vcc *vcc, struct sk_buff *skb)
{
        if (vcc->pop)
                vcc->pop (vcc, skb);
        else
                dev_kfree_skb (skb);
}


/*************
**  decode  **
*************/

static inline struct udsl_vcc_data *udsl_find_vcc (struct udsl_instance_data *instance, short vpi, int vci)
{
        struct udsl_vcc_data *vcc;

        list_for_each_entry (vcc, &instance->vcc_list, list)
                if ((vcc->vci == vci) && (vcc->vpi == vpi))
                        return vcc;
        return NULL;
}

static void udsl_extract_cells (struct udsl_instance_data *instance, unsigned char *source, unsigned int howmany)
{
        struct udsl_vcc_data *cached_vcc = NULL;
        struct atm_vcc *vcc;
        struct sk_buff *sarb;
        struct udsl_vcc_data *vcc_data;
        int cached_vci = 0;
        unsigned int i;
        int pti;
        int vci;
        short cached_vpi = 0;
        short vpi;

        for (i = 0; i < howmany; i++, source += ATM_CELL_SIZE) {
                vpi = ((source [0] & 0x0f) << 4) | (source [1] >> 4);
                vci = ((source [1] & 0x0f) << 12) | (source [2] << 4) | (source [3] >> 4);
                pti = (source [3] & 0x2) != 0;

                vdbg ("udsl_extract_cells: vpi %hd, vci %d, pti %d", vpi, vci, pti);

                if (cached_vcc && (vci == cached_vci) && (vpi == cached_vpi))
                        vcc_data = cached_vcc;
                else if ((vcc_data = udsl_find_vcc (instance, vpi, vci))) {
                        cached_vcc = vcc_data;
                        cached_vpi = vpi;
                        cached_vci = vci;
                } else {
                        dbg ("udsl_extract_cells: unknown vpi/vci (%hd/%d)!", vpi, vci);
                        continue;
                }

                vcc = vcc_data->vcc;
                sarb = vcc_data->sarb;

                if (sarb->tail + ATM_CELL_PAYLOAD > sarb->end) {
                        dbg ("udsl_extract_cells: buffer overrun (sarb->len %u, vcc: 0x%p)!", sarb->len, vcc);
                        /* discard cells already received */
                        skb_trim (sarb, 0);
                }

                memcpy (sarb->tail, source + ATM_CELL_HEADER, ATM_CELL_PAYLOAD);
                __skb_put (sarb, ATM_CELL_PAYLOAD);

                if (pti) {
                        struct sk_buff *skb;
                        unsigned int length;
                        unsigned int pdu_length;

                        length = (source [ATM_CELL_SIZE - 6] << 8) + source [ATM_CELL_SIZE - 5];

                        /* guard against overflow */
                        if (length > ATM_MAX_AAL5_PDU) {
                                dbg ("udsl_extract_cells: bogus length %u (vcc: 0x%p)!", length, vcc);
                                atomic_inc (&vcc->stats->rx_err);
                                goto out;
                        }

                        pdu_length = UDSL_NUM_CELLS (length) * ATM_CELL_PAYLOAD;

                        if (sarb->len < pdu_length) {
                                dbg ("udsl_extract_cells: bogus pdu_length %u (sarb->len: %u, vcc: 0x%p)!", pdu_length, sarb->len, vcc);
                                atomic_inc (&vcc->stats->rx_err);
                                goto out;
                        }

                        if (crc32_be (~0, sarb->tail - pdu_length, pdu_length) != 0xc704dd7b) {
                                dbg ("udsl_extract_cells: packet failed crc check (vcc: 0x%p)!", vcc);
                                atomic_inc (&vcc->stats->rx_err);
                                goto out;
                        }

                        vdbg ("udsl_extract_cells: got packet (length: %u, pdu_length: %u, vcc: 0x%p)", length, pdu_length, vcc);

                        if (!(skb = dev_alloc_skb (length))) {
                                dbg ("udsl_extract_cells: no memory for skb (length: %u)!", length);
                                atomic_inc (&vcc->stats->rx_drop);
                                goto out;
                        }

                        vdbg ("udsl_extract_cells: allocated new sk_buff (skb: 0x%p, skb->truesize: %u)", skb, skb->truesize);

                        if (!atm_charge (vcc, skb->truesize)) {
                                dbg ("udsl_extract_cells: failed atm_charge (skb->truesize: %u)!", skb->truesize);
                                dev_kfree_skb (skb);
                                goto out; /* atm_charge increments rx_drop */
                        }

                        memcpy (skb->data, sarb->tail - pdu_length, length);
                        __skb_put (skb, length);

                        vdbg ("udsl_extract_cells: sending skb 0x%p, skb->len %u, skb->truesize %u", skb, skb->len, skb->truesize);

                        PACKETDEBUG (skb->data, skb->len);

                        vcc->push (vcc, skb);

                        atomic_inc (&vcc->stats->rx);
out:
                        skb_trim (sarb, 0);
                }
        }
}


/*************
**  encode  **
*************/

static const unsigned char zeros [ATM_CELL_PAYLOAD];

static void udsl_groom_skb (struct atm_vcc *vcc, struct sk_buff *skb)
{
        struct udsl_control *ctrl = UDSL_SKB (skb);
        unsigned int zero_padding;
        u32 crc;

        ctrl->atm_data.vcc = vcc;
        ctrl->cell_header [0] = vcc->vpi >> 4;
        ctrl->cell_header [1] = (vcc->vpi << 4) | (vcc->vci >> 12);
        ctrl->cell_header [2] = vcc->vci >> 4;
        ctrl->cell_header [3] = vcc->vci << 4;
        ctrl->cell_header [4] = 0xec;

        ctrl->num_cells = UDSL_NUM_CELLS (skb->len);
        ctrl->num_entire = skb->len / ATM_CELL_PAYLOAD;

        zero_padding = ctrl->num_cells * ATM_CELL_PAYLOAD - skb->len - ATM_AAL5_TRAILER;

        if (ctrl->num_entire + 1 < ctrl->num_cells)
                ctrl->pdu_padding = zero_padding - (ATM_CELL_PAYLOAD - ATM_AAL5_TRAILER);
        else
                ctrl->pdu_padding = zero_padding;

        ctrl->aal5_trailer [0] = 0; /* UU = 0 */
        ctrl->aal5_trailer [1] = 0; /* CPI = 0 */
        ctrl->aal5_trailer [2] = skb->len >> 8;
        ctrl->aal5_trailer [3] = skb->len;

        crc = crc32_be (~0, skb->data, skb->len);
        crc = crc32_be (crc, zeros, zero_padding);
        crc = crc32_be (crc, ctrl->aal5_trailer, 4);
        crc = ~crc;

        ctrl->aal5_trailer [4] = crc >> 24;
        ctrl->aal5_trailer [5] = crc >> 16;
        ctrl->aal5_trailer [6] = crc >> 8;
        ctrl->aal5_trailer [7] = crc;
}

static unsigned int udsl_write_cells (unsigned int howmany, struct sk_buff *skb, unsigned char **target_p)
{
        struct udsl_control *ctrl = UDSL_SKB (skb);
        unsigned char *target = *target_p;
        unsigned int nc, ne, i;

        vdbg ("udsl_write_cells: howmany=%u, skb->len=%d, num_cells=%u, num_entire=%u, pdu_padding=%u", howmany, skb->len, ctrl->num_cells, ctrl->num_entire, ctrl->pdu_padding);

        nc = ctrl->num_cells;
        ne = min (howmany, ctrl->num_entire);

        for (i = 0; i < ne; i++) {
                memcpy (target, ctrl->cell_header, ATM_CELL_HEADER);
                target += ATM_CELL_HEADER;
                memcpy (target, skb->data, ATM_CELL_PAYLOAD);
                target += ATM_CELL_PAYLOAD;
                __skb_pull (skb, ATM_CELL_PAYLOAD);
        }

        ctrl->num_entire -= ne;

        if (!(ctrl->num_cells -= ne) || !(howmany -= ne))
                goto out;

        memcpy (target, ctrl->cell_header, ATM_CELL_HEADER);
        target += ATM_CELL_HEADER;
        memcpy (target, skb->data, skb->len);
        target += skb->len;
        __skb_pull (skb, skb->len);
        memset (target, 0, ctrl->pdu_padding);
        target += ctrl->pdu_padding;

        if (--ctrl->num_cells) {
                if (!--howmany) {
                        ctrl->pdu_padding = ATM_CELL_PAYLOAD - ATM_AAL5_TRAILER;
                        goto out;
                }

                memcpy (target, ctrl->cell_header, ATM_CELL_HEADER);
                target += ATM_CELL_HEADER;
                memset (target, 0, ATM_CELL_PAYLOAD - ATM_AAL5_TRAILER);
                target += ATM_CELL_PAYLOAD - ATM_AAL5_TRAILER;

                DEBUG_ON (--ctrl->num_cells);
        }

        memcpy (target, ctrl->aal5_trailer, ATM_AAL5_TRAILER);
        target += ATM_AAL5_TRAILER;
        /* set pti bit in last cell */
        *(target + 3 - ATM_CELL_SIZE) |= 0x2;

out:
        *target_p = target;
        return nc - ctrl->num_cells;
}


/**************
**  receive  **
**************/

static void udsl_complete_receive (struct urb *urb)
{
        struct udsl_receive_buffer *buf;
        struct udsl_instance_data *instance;
        struct udsl_receiver *rcv;
        unsigned long flags;

        if (!urb || !(rcv = urb->context)) {
                dbg ("udsl_complete_receive: bad urb!");
                return;
        }

        instance = rcv->instance;
        buf = rcv->buffer;

        buf->filled_cells = urb->actual_length / ATM_CELL_SIZE;

        vdbg ("udsl_complete_receive: urb 0x%p, status %d, actual_length %d, filled_cells %u, rcv 0x%p, buf 0x%p", urb, urb->status, urb->actual_length, buf->filled_cells, rcv, buf);

        DEBUG_ON (buf->filled_cells > rcv_buf_size);

        /* may not be in_interrupt() */
        spin_lock_irqsave (&instance->receive_lock, flags);
        list_add (&rcv->list, &instance->spare_receivers);
        list_add_tail (&buf->list, &instance->filled_receive_buffers);
        if (likely (!urb->status))
                tasklet_schedule (&instance->receive_tasklet);
        spin_unlock_irqrestore (&instance->receive_lock, flags);
}

static void udsl_process_receive (unsigned long data)
{
        struct udsl_receive_buffer *buf;
        struct udsl_instance_data *instance = (struct udsl_instance_data *) data;
        struct udsl_receiver *rcv;
        int err;

made_progress:
        while (!list_empty (&instance->spare_receive_buffers)) {
                spin_lock_irq (&instance->receive_lock);
                if (list_empty (&instance->spare_receivers)) {
                        spin_unlock_irq (&instance->receive_lock);
                        break;
                }
                rcv = list_entry (instance->spare_receivers.next, struct udsl_receiver, list);
                list_del (&rcv->list);
                spin_unlock_irq (&instance->receive_lock);

                buf = list_entry (instance->spare_receive_buffers.next, struct udsl_receive_buffer, list);
                list_del (&buf->list);

                rcv->buffer = buf;

                FILL_BULK_URB (rcv->urb,
                               instance->usb_dev,
                               usb_rcvbulkpipe (instance->usb_dev, UDSL_ENDPOINT_DATA_IN),
                               buf->base,
                               rcv_buf_size * ATM_CELL_SIZE,
                               udsl_complete_receive,
                               rcv);
                rcv->urb->transfer_flags |= USB_QUEUE_BULK;

                vdbg ("udsl_process_receive: sending urb 0x%p, rcv 0x%p, buf 0x%p", rcv->urb, rcv, buf);

                if ((err = usb_submit_urb(rcv->urb)) < 0) {
                        dbg ("udsl_process_receive: urb submission failed (%d)!", err);
                        list_add (&buf->list, &instance->spare_receive_buffers);
                        spin_lock_irq (&instance->receive_lock);
                        list_add (&rcv->list, &instance->spare_receivers);
                        spin_unlock_irq (&instance->receive_lock);
                        break;
                }
        }

        spin_lock_irq (&instance->receive_lock);
        if (list_empty (&instance->filled_receive_buffers)) {
                spin_unlock_irq (&instance->receive_lock);
                return; /* done - no more buffers */
        }
        buf = list_entry (instance->filled_receive_buffers.next, struct udsl_receive_buffer, list);
        list_del (&buf->list);
        spin_unlock_irq (&instance->receive_lock);
        vdbg ("udsl_process_receive: processing buf 0x%p", buf);
        udsl_extract_cells (instance, buf->base, buf->filled_cells);
        list_add (&buf->list, &instance->spare_receive_buffers);
        goto made_progress;
}


/***********
**  send  **
***********/

static void udsl_complete_send (struct urb *urb)
{
        struct udsl_instance_data *instance;
        struct udsl_sender *snd;
        unsigned long flags;

        if (!urb || !(snd = urb->context) || !(instance = snd->instance)) {
                dbg ("udsl_complete_send: bad urb!");
                return;
        }

        vdbg ("udsl_complete_send: urb 0x%p, status %d, snd 0x%p, buf 0x%p", urb, urb->status, snd, snd->buffer);

        /* may not be in_interrupt() */
        spin_lock_irqsave (&instance->send_lock, flags);
        list_add (&snd->list, &instance->spare_senders);
        list_add (&snd->buffer->list, &instance->spare_send_buffers);
        tasklet_schedule (&instance->send_tasklet);
        spin_unlock_irqrestore (&instance->send_lock, flags);
}

static void udsl_process_send (unsigned long data)
{
        struct udsl_send_buffer *buf;
        struct udsl_instance_data *instance = (struct udsl_instance_data *) data;
        struct sk_buff *skb;
        struct udsl_sender *snd;
        int err;
        unsigned int num_written;

made_progress:
        spin_lock_irq (&instance->send_lock);
        while (!list_empty (&instance->spare_senders)) {
                if (!list_empty (&instance->filled_send_buffers)) {
                        buf = list_entry (instance->filled_send_buffers.next, struct udsl_send_buffer, list);
                        list_del (&buf->list);
                } else if ((buf = instance->current_buffer)) {
                        instance->current_buffer = NULL;
                } else /* all buffers empty */
                        break;

                snd = list_entry (instance->spare_senders.next, struct udsl_sender, list);
                list_del (&snd->list);
                spin_unlock_irq (&instance->send_lock);

                snd->buffer = buf;
                FILL_BULK_URB (snd->urb,
                               instance->usb_dev,
                               usb_sndbulkpipe (instance->usb_dev, UDSL_ENDPOINT_DATA_OUT),
                               buf->base,
                               (snd_buf_size - buf->free_cells) * ATM_CELL_SIZE,
                               udsl_complete_send,
                               snd);
                snd->urb->transfer_flags |= USB_QUEUE_BULK;

                vdbg ("udsl_process_send: submitting urb 0x%p (%d cells), snd 0x%p, buf 0x%p", snd->urb, snd_buf_size - buf->free_cells, snd, buf);

                if ((err = usb_submit_urb(snd->urb)) < 0) {
                        dbg ("udsl_process_send: urb submission failed (%d)!", err);
                        spin_lock_irq (&instance->send_lock);
                        list_add (&snd->list, &instance->spare_senders);
                        spin_unlock_irq (&instance->send_lock);
                        list_add (&buf->list, &instance->filled_send_buffers);
                        return; /* bail out */
                }

                spin_lock_irq (&instance->send_lock);
        } /* while */
        spin_unlock_irq (&instance->send_lock);

        if (!instance->current_skb && !(instance->current_skb = skb_dequeue (&instance->sndqueue)))
                return; /* done - no more skbs */

        skb = instance->current_skb;

        if (!(buf = instance->current_buffer)) {
                spin_lock_irq (&instance->send_lock);
                if (list_empty (&instance->spare_send_buffers)) {
                        instance->current_buffer = NULL;
                        spin_unlock_irq (&instance->send_lock);
                        return; /* done - no more buffers */
                }
                buf = list_entry (instance->spare_send_buffers.next, struct udsl_send_buffer, list);
                list_del (&buf->list);
                spin_unlock_irq (&instance->send_lock);

                buf->free_start = buf->base;
                buf->free_cells = snd_buf_size;

                instance->current_buffer = buf;
        }

        num_written = udsl_write_cells (buf->free_cells, skb, &buf->free_start);

        vdbg ("udsl_process_send: wrote %u cells from skb 0x%p to buffer 0x%p", num_written, skb, buf);

        if (!(buf->free_cells -= num_written)) {
                list_add_tail (&buf->list, &instance->filled_send_buffers);
                instance->current_buffer = NULL;
        }

        vdbg ("udsl_process_send: buffer contains %d cells, %d left", snd_buf_size - buf->free_cells, buf->free_cells);

        if (!UDSL_SKB (skb)->num_cells) {
                struct atm_vcc *vcc = UDSL_SKB (skb)->atm_data.vcc;

                udsl_pop (vcc, skb);
                instance->current_skb = NULL;

                atomic_inc (&vcc->stats->tx);
        }

        goto made_progress;
}

static void udsl_cancel_send (struct udsl_instance_data *instance, struct atm_vcc *vcc)
{
        struct sk_buff *skb, *n;

        dbg ("udsl_cancel_send entered");
        spin_lock_irq (&instance->sndqueue.lock);
        for (skb = instance->sndqueue.next, n = skb->next; skb != (struct sk_buff *)&instance->sndqueue; skb = n, n = skb->next)
                if (UDSL_SKB (skb)->atm_data.vcc == vcc) {
                        dbg ("udsl_cancel_send: popping skb 0x%p", skb);
                        __skb_unlink (skb, &instance->sndqueue);
                        udsl_pop (vcc, skb);
                }
        spin_unlock_irq (&instance->sndqueue.lock);

        tasklet_disable (&instance->send_tasklet);
        if ((skb = instance->current_skb) && (UDSL_SKB (skb)->atm_data.vcc == vcc)) {
                dbg ("udsl_cancel_send: popping current skb (0x%p)", skb);
                instance->current_skb = NULL;
                udsl_pop (vcc, skb);
        }
        tasklet_enable (&instance->send_tasklet);
        dbg ("udsl_cancel_send done");
}

static int udsl_atm_send (struct atm_vcc *vcc, struct sk_buff *skb)
{
        struct udsl_instance_data *instance = vcc->dev->dev_data;
        int err;

        vdbg ("udsl_atm_send called (skb 0x%p, len %u)", skb, skb->len);

        if (!instance || !instance->usb_dev) {
                dbg ("udsl_atm_send: NULL data!");
                err = -ENODEV;
                goto fail;
        }

        if (vcc->qos.aal != ATM_AAL5) {
                dbg ("udsl_atm_send: unsupported ATM type %d!", vcc->qos.aal);
                err = -EINVAL;
                goto fail;
        }

        if (skb->len > ATM_MAX_AAL5_PDU) {
                dbg ("udsl_atm_send: packet too long (%d vs %d)!", skb->len, ATM_MAX_AAL5_PDU);
                err = -EINVAL;
                goto fail;
        }

        PACKETDEBUG (skb->data, skb->len);

        udsl_groom_skb (vcc, skb);
        skb_queue_tail (&instance->sndqueue, skb);
        tasklet_schedule (&instance->send_tasklet);

        return 0;

fail:
        udsl_pop (vcc, skb);
        return err;
}


/**********
**  ATM  **
**********/

static void udsl_atm_dev_close (struct atm_dev *dev)
{
        struct udsl_instance_data *instance = dev->dev_data;

        if (!instance) {
                dbg ("udsl_atm_dev_close: NULL instance!");
                return;
        }

        dbg ("udsl_atm_dev_close: queue has %u elements", instance->sndqueue.qlen);

        tasklet_kill (&instance->receive_tasklet);
        tasklet_kill (&instance->send_tasklet);
        kfree (instance);
        dev->dev_data = NULL;
}

static int udsl_atm_proc_read (struct atm_dev *atm_dev, loff_t *pos, char *page)
{
        struct udsl_instance_data *instance = atm_dev->dev_data;
        int left = *pos;

        if (!instance) {
                dbg ("udsl_atm_proc_read: NULL instance!");
                return -ENODEV;
        }

        if (!left--)
                return sprintf (page, "%s\n", instance->description);

        if (!left--)
                return sprintf (page, "MAC: %02x:%02x:%02x:%02x:%02x:%02x\n",
                                atm_dev->esi [0], atm_dev->esi [1], atm_dev->esi [2],
                                atm_dev->esi [3], atm_dev->esi [4], atm_dev->esi [5]);

        if (!left--)
                return sprintf (page, "AAL5: tx %d ( %d err ), rx %d ( %d err, %d drop )\n",
                                atomic_read (&atm_dev->stats.aal5.tx),
                                atomic_read (&atm_dev->stats.aal5.tx_err),
                                atomic_read (&atm_dev->stats.aal5.rx),
                                atomic_read (&atm_dev->stats.aal5.rx_err),
                                atomic_read (&atm_dev->stats.aal5.rx_drop));

        if (!left--) {
                switch (atm_dev->signal) {
                case ATM_PHY_SIG_FOUND:
                        sprintf (page, "Line up");
                        break;
                case ATM_PHY_SIG_LOST:
                        sprintf (page, "Line down");
                        break;
                default:
                        sprintf (page, "Line state unknown");
                        break;
                }

                if (instance->usb_dev) {
                        if (!instance->firmware_loaded)
                                strcat (page, ", no firmware\n");
                        else
                                strcat (page, ", firmware loaded\n");
                } else
                        strcat (page, ", disconnected\n");

                return strlen (page);
        }

        return 0;
}

static int udsl_atm_open (struct atm_vcc *vcc, short vpi, int vci)
{
        struct udsl_instance_data *instance = vcc->dev->dev_data;
        struct udsl_vcc_data *new;
        unsigned int max_pdu;

        dbg ("udsl_atm_open: vpi %hd, vci %d", vpi, vci);

        if (!instance || !instance->usb_dev) {
                dbg ("udsl_atm_open: NULL data!");
                return -ENODEV;
        }

        if ((vpi == ATM_VPI_ANY) || (vci == ATM_VCI_ANY))
                return -EINVAL;

        /* only support AAL5 */
        if ((vcc->qos.aal != ATM_AAL5) || (vcc->qos.rxtp.max_sdu < 0) || (vcc->qos.rxtp.max_sdu > ATM_MAX_AAL5_PDU)) {
                dbg ("udsl_atm_open: unsupported ATM type %d!", vcc->qos.aal);
                return -EINVAL;
        }

        if (!instance->firmware_loaded) {
                dbg ("udsl_atm_open: firmware not loaded!");
                return -EAGAIN;
        }

        down (&instance->serialize); /* vs self, udsl_atm_close */

        if (udsl_find_vcc (instance, vpi, vci)) {
                dbg ("udsl_atm_open: %hd/%d already in use!", vpi, vci);
                up (&instance->serialize);
                return -EADDRINUSE;
        }

        if (!(new = kmalloc (sizeof (struct udsl_vcc_data), GFP_KERNEL))) {
                dbg ("udsl_atm_open: no memory for vcc_data!");
                up (&instance->serialize);
                return -ENOMEM;
        }

        memset (new, 0, sizeof (struct udsl_vcc_data));
        new->vcc = vcc;
        new->vpi = vpi;
        new->vci = vci;

        /* udsl_extract_cells requires at least one cell */
        max_pdu = max (1, UDSL_NUM_CELLS (vcc->qos.rxtp.max_sdu)) * ATM_CELL_PAYLOAD;
        if (!(new->sarb = alloc_skb (max_pdu, GFP_KERNEL))) {
                dbg ("udsl_atm_open: no memory for SAR buffer!");
                kfree (new);
                up (&instance->serialize);
                return -ENOMEM;
        }

        vcc->dev_data = new;
        vcc->vpi = vpi;
        vcc->vci = vci;

        tasklet_disable (&instance->receive_tasklet);
        list_add (&new->list, &instance->vcc_list);
        tasklet_enable (&instance->receive_tasklet);

        set_bit (ATM_VF_ADDR, &vcc->flags);
        set_bit (ATM_VF_PARTIAL, &vcc->flags);
        set_bit (ATM_VF_READY, &vcc->flags);

        up (&instance->serialize);

        tasklet_schedule (&instance->receive_tasklet);

        dbg ("udsl_atm_open: allocated vcc data 0x%p (max_pdu: %u)", new, max_pdu);

        return 0;
}

static void udsl_atm_close (struct atm_vcc *vcc)
{
        struct udsl_instance_data *instance = vcc->dev->dev_data;
        struct udsl_vcc_data *vcc_data = vcc->dev_data;

        dbg ("udsl_atm_close called");

        if (!instance || !vcc_data) {
                dbg ("udsl_atm_close: NULL data!");
                return;
        }

        dbg ("udsl_atm_close: deallocating vcc 0x%p with vpi %d vci %d", vcc_data, vcc_data->vpi, vcc_data->vci);

        udsl_cancel_send (instance, vcc);

        down (&instance->serialize); /* vs self, udsl_atm_open */

        tasklet_disable (&instance->receive_tasklet);
        list_del (&vcc_data->list);
        tasklet_enable (&instance->receive_tasklet);

        kfree_skb (vcc_data->sarb);
        vcc_data->sarb = NULL;

        kfree (vcc_data);
        vcc->dev_data = NULL;

        vcc->vpi = ATM_VPI_UNSPEC;
        vcc->vci = ATM_VCI_UNSPEC;
        clear_bit (ATM_VF_READY, &vcc->flags);
        clear_bit (ATM_VF_PARTIAL, &vcc->flags);
        clear_bit (ATM_VF_ADDR, &vcc->flags);

        up (&instance->serialize);

        dbg ("udsl_atm_close successful");
}

static int udsl_atm_ioctl (struct atm_dev *dev, unsigned int cmd, void *arg)
{
        switch (cmd) {

        case ATM_QUERYLOOP:
                return put_user (ATM_LM_NONE, (int *) arg) ? -EFAULT : 0;
        default:
                return -ENOIOCTLCMD;
        }
}


/**********
**  USB  **
**********/

static int udsl_set_alternate (struct udsl_instance_data *instance)
{
        down (&instance->serialize); /* vs self */
        if (!instance->firmware_loaded) {
                int ret;

                if ((ret = usb_set_interface (instance->usb_dev, 1, 1)) < 0) {
                        dbg ("udsl_set_alternate: usb_set_interface returned %d!", ret);
                        up (&instance->serialize);
                        return ret;
                }
                instance->firmware_loaded = 1;
        }
        up (&instance->serialize);

        tasklet_schedule (&instance->receive_tasklet);

        return 0;
}

static int udsl_usb_ioctl (struct usb_device *dev, unsigned int code, void *user_data)
{
        struct usb_interface *intf = usb_ifnum_to_if (dev, 1);
        struct udsl_instance_data *instance = intf->private_data;

        dbg ("udsl_usb_ioctl entered");

        if (!instance) {
                dbg ("udsl_usb_ioctl: NULL instance!");
                return -ENODEV;
        }

        switch (code) {
        case UDSL_IOCTL_LINE_UP:
                instance->atm_dev->signal = ATM_PHY_SIG_FOUND;
                return udsl_set_alternate (instance);
        case UDSL_IOCTL_LINE_DOWN:
                instance->atm_dev->signal = ATM_PHY_SIG_LOST;
                return 0;
        default:
                return -ENOTTY;
        }
}

static void *udsl_usb_probe (struct usb_device *dev, unsigned int ifnum, const struct usb_device_id *id)
{
        struct udsl_instance_data *instance;
        unsigned char mac_str [13];
        int i, length;
        char *buf;

        dbg ("udsl_usb_probe: trying device with vendor=0x%x, product=0x%x, ifnum %d",
             dev->descriptor.idVendor, dev->descriptor.idProduct, ifnum);

        if ((dev->descriptor.bDeviceClass != USB_CLASS_VENDOR_SPEC) ||
            (dev->descriptor.idVendor != SPEEDTOUCH_VENDORID) ||
            (dev->descriptor.idProduct != SPEEDTOUCH_PRODUCTID) || (ifnum != 1))
                return NULL;

        dbg ("udsl_usb_probe: device accepted");

        /* instance init */
        if (!(instance = kmalloc (sizeof (struct udsl_instance_data), GFP_KERNEL))) {
                dbg ("udsl_usb_probe: no memory for instance data!");
                return NULL;
        }

        memset (instance, 0, sizeof (struct udsl_instance_data));

        init_MUTEX (&instance->serialize);

        instance->usb_dev = dev;

        INIT_LIST_HEAD (&instance->vcc_list);

        spin_lock_init (&instance->receive_lock);
        INIT_LIST_HEAD (&instance->spare_receivers);
        INIT_LIST_HEAD (&instance->filled_receive_buffers);

        tasklet_init (&instance->receive_tasklet, udsl_process_receive, (unsigned long) instance);
        INIT_LIST_HEAD (&instance->spare_receive_buffers);

        skb_queue_head_init (&instance->sndqueue);

        spin_lock_init (&instance->send_lock);
        INIT_LIST_HEAD (&instance->spare_senders);
        INIT_LIST_HEAD (&instance->spare_send_buffers);

        tasklet_init (&instance->send_tasklet, udsl_process_send, (unsigned long) instance);
        INIT_LIST_HEAD (&instance->filled_send_buffers);

        /* receive init */
        for (i = 0; i < num_rcv_urbs; i++) {
                struct udsl_receiver *rcv = &(instance->receivers [i]);

                if (!(rcv->urb = usb_alloc_urb (0))) {
                        dbg ("udsl_usb_probe: no memory for receive urb %d!", i);
                        goto fail;
                }

                rcv->instance = instance;

                list_add (&rcv->list, &instance->spare_receivers);
        }

        for (i = 0; i < num_rcv_bufs; i++) {
                struct udsl_receive_buffer *buf = &(instance->receive_buffers [i]);

                if (!(buf->base = kmalloc (rcv_buf_size * ATM_CELL_SIZE, GFP_KERNEL))) {
                        dbg ("udsl_usb_probe: no memory for receive buffer %d!", i);
                        goto fail;
                }

                list_add (&buf->list, &instance->spare_receive_buffers);
        }

        /* send init */
        for (i = 0; i < num_snd_urbs; i++) {
                struct udsl_sender *snd = &(instance->senders [i]);

                if (!(snd->urb = usb_alloc_urb (0))) {
                        dbg ("udsl_usb_probe: no memory for send urb %d!", i);
                        goto fail;
                }

                snd->instance = instance;

                list_add (&snd->list, &instance->spare_senders);
        }

        for (i = 0; i < num_snd_bufs; i++) {
                struct udsl_send_buffer *buf = &(instance->send_buffers [i]);

                if (!(buf->base = kmalloc (snd_buf_size * ATM_CELL_SIZE, GFP_KERNEL))) {
                        dbg ("udsl_usb_probe: no memory for send buffer %d!", i);
                        goto fail;
                }

                list_add (&buf->list, &instance->spare_send_buffers);
        }

        /* ATM init */
        if (!(instance->atm_dev = atm_dev_register (udsl_driver_name, &udsl_atm_devops, -1, 0))) {
                dbg ("udsl_usb_probe: failed to register ATM device!");
                goto fail;
        }

        instance->atm_dev->ci_range.vpi_bits = ATM_CI_MAX;
        instance->atm_dev->ci_range.vci_bits = ATM_CI_MAX;
        instance->atm_dev->signal = ATM_PHY_SIG_UNKNOWN;

        /* temp init ATM device, set to 128kbit */
        instance->atm_dev->link_rate = 128 * 1000 / 424;

        /* set MAC address, it is stored in the serial number */
        memset (instance->atm_dev->esi, 0, sizeof (instance->atm_dev->esi));
        if (usb_string (dev, dev->descriptor.iSerialNumber, mac_str, sizeof (mac_str)) == 12)
                for (i = 0; i < 6; i++)
                        instance->atm_dev->esi [i] = (hex2int (mac_str [i * 2]) * 16) + (hex2int (mac_str [i * 2 + 1]));

        /* device description */
        buf = instance->description;
        length = sizeof (instance->description);

        if ((i = usb_string (dev, dev->descriptor.iProduct, buf, length)) < 0)
                goto finish;

        buf += i;
        length -= i;

        i = snprintf (buf, length, " (");
        buf += i;
        length -= i;

        if (length <= 0 || (i = usb_make_path (dev, buf, length)) < 0)
                goto finish;

        buf += i;
        length -= i;

        snprintf (buf, length, ")");

finish:
        /* ready for ATM callbacks */
        wmb ();
        instance->atm_dev->dev_data = instance;

        return instance;

fail:
        for (i = 0; i < num_snd_bufs; i++)
                kfree (instance->send_buffers [i].base);

        for (i = 0; i < num_snd_urbs; i++)
                usb_free_urb (instance->senders [i].urb);

        for (i = 0; i < num_rcv_bufs; i++)
                kfree (instance->receive_buffers [i].base);

        for (i = 0; i < num_rcv_urbs; i++)
                usb_free_urb (instance->receivers [i].urb);

        kfree (instance);

        return NULL;
}

static void udsl_usb_disconnect (struct usb_device *dev, void *ptr)
{
        struct udsl_instance_data *instance = ptr;
        struct list_head *pos;
        unsigned int count;
        int result, i;

        dbg ("udsl_usb_disconnect entered");

        if (!instance) {
                dbg ("udsl_usb_disconnect: NULL instance!");
                return;
        }

        /* receive finalize */
        tasklet_disable (&instance->receive_tasklet);

        for (i = 0; i < num_rcv_urbs; i++)
                if ((result = usb_unlink_urb (instance->receivers [i].urb)) < 0)
                        dbg ("udsl_usb_disconnect: usb_unlink_urb on receive urb %d returned %d!", i, result);

        /* wait for completion handlers to finish */
        do {
                count = 0;
                spin_lock_irq (&instance->receive_lock);
                list_for_each (pos, &instance->spare_receivers)
                        DEBUG_ON (++count > num_rcv_urbs);
                spin_unlock_irq (&instance->receive_lock);

                dbg ("udsl_usb_disconnect: found %u spare receivers", count);

                if (count == num_rcv_urbs)
                        break;

                set_current_state (TASK_RUNNING);
                schedule ();
        } while (1);

        /* no need to take the spinlock */
        INIT_LIST_HEAD (&instance->filled_receive_buffers);
        INIT_LIST_HEAD (&instance->spare_receive_buffers);

        tasklet_enable (&instance->receive_tasklet);

        for (i = 0; i < num_rcv_urbs; i++)
                usb_free_urb (instance->receivers [i].urb);

        for (i = 0; i < num_rcv_bufs; i++)
                kfree (instance->receive_buffers [i].base);

        /* send finalize */
        tasklet_disable (&instance->send_tasklet);

        for (i = 0; i < num_snd_urbs; i++)
                if ((result = usb_unlink_urb (instance->senders [i].urb)) < 0)
                        dbg ("udsl_usb_disconnect: usb_unlink_urb on send urb %d returned %d!", i, result);

        /* wait for completion handlers to finish */
        do {
                count = 0;
                spin_lock_irq (&instance->send_lock);
                list_for_each (pos, &instance->spare_senders)
                        DEBUG_ON (++count > num_snd_urbs);
                spin_unlock_irq (&instance->send_lock);

                dbg ("udsl_usb_disconnect: found %u spare senders", count);

                if (count == num_snd_urbs)
                        break;

                set_current_state (TASK_RUNNING);
                schedule ();
        } while (1);

        /* no need to take the spinlock */
        INIT_LIST_HEAD (&instance->spare_senders);
        INIT_LIST_HEAD (&instance->spare_send_buffers);
        instance->current_buffer = NULL;

        tasklet_enable (&instance->send_tasklet);

        for (i = 0; i < num_snd_urbs; i++)
                usb_free_urb (instance->senders [i].urb);

        for (i = 0; i < num_snd_bufs; i++)
                kfree (instance->send_buffers [i].base);

        wmb ();
        instance->usb_dev = NULL;

        /* ATM finalize */
        shutdown_atm_dev (instance->atm_dev); /* frees instance, kills tasklets */
}


/***********
**  init  **
***********/

static int __init udsl_usb_init (void)
{
        dbg ("udsl_usb_init: driver version " DRIVER_VERSION);

        if (sizeof (struct udsl_control) > sizeof (((struct sk_buff *)0)->cb)) {
                printk (KERN_ERR __FILE__ ": unusable with this kernel!\n");
                return -EIO;
        }

        if ((num_rcv_urbs > UDSL_MAX_RCV_URBS) || (num_snd_urbs > UDSL_MAX_SND_URBS) ||
            (num_rcv_bufs > UDSL_MAX_RCV_BUFS) || (num_snd_bufs > UDSL_MAX_SND_BUFS) ||
            (rcv_buf_size > UDSL_MAX_RCV_BUF_SIZE) || (snd_buf_size > UDSL_MAX_SND_BUF_SIZE))
                return -EINVAL;

        return usb_register (&udsl_usb_driver);
}

static void __exit udsl_usb_cleanup (void)
{
        dbg ("udsl_usb_cleanup entered");

        usb_deregister (&udsl_usb_driver);
}

module_init (udsl_usb_init);
module_exit (udsl_usb_cleanup);

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


/************
**  debug  **
************/

#ifdef VERBOSE_DEBUG
static int udsl_print_packet (const unsigned char *data, int len)
{
        unsigned char buffer [256];
        int i = 0, j = 0;

        for (i = 0; i < len;) {
                buffer [0] = '\0';
                sprintf (buffer, "%.3d :", i);
                for (j = 0; (j < 16) && (i < len); j++, i++) {
                        sprintf (buffer, "%s %2.2x", buffer, data [i]);
                }
                dbg ("%s", buffer);
        }
        return i;
}
#endif