Add the rt linux 4.1.3-rt3 as base
[kvmfornfv.git] / kernel / drivers / usb / atm / usbatm.c
diff --git a/kernel/drivers/usb/atm/usbatm.c b/kernel/drivers/usb/atm/usbatm.c
new file mode 100644 (file)
index 0000000..dada014
--- /dev/null
@@ -0,0 +1,1344 @@
+/******************************************************************************
+ *  usbatm.c - Generic USB xDSL driver core
+ *
+ *  Copyright (C) 2001, Alcatel
+ *  Copyright (C) 2003, Duncan Sands, SolNegro, Josep Comas
+ *  Copyright (C) 2004, David Woodhouse, Roman Kagan
+ *
+ *  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, Duncan Sands (duncan.sands@free.fr) and David Woodhouse
+ *
+ *  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:      - 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
+ *             usbatm_usb_send_data_context->urb to a pointer and adding code
+ *             to alloc and free it
+ *             - remove_wait_queue() added to usbatm_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 usbatm_usb_send_data()
+ *  1.1:       - Turned off packet debugging
+ *
+ */
+
+#include "usbatm.h"
+
+#include <asm/uaccess.h>
+#include <linux/crc32.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/netdevice.h>
+#include <linux/proc_fs.h>
+#include <linux/sched.h>
+#include <linux/signal.h>
+#include <linux/slab.h>
+#include <linux/stat.h>
+#include <linux/timer.h>
+#include <linux/wait.h>
+#include <linux/kthread.h>
+#include <linux/ratelimit.h>
+
+#ifdef VERBOSE_DEBUG
+static int usbatm_print_packet(struct usbatm_data *instance, const unsigned char *data, int len);
+#define PACKETDEBUG(arg...)    usbatm_print_packet(arg)
+#define vdbg(arg...)           dev_dbg(arg)
+#else
+#define PACKETDEBUG(arg...)
+#define vdbg(arg...)
+#endif
+
+#define DRIVER_AUTHOR  "Johan Verrept, Duncan Sands <duncan.sands@free.fr>"
+#define DRIVER_VERSION "1.10"
+#define DRIVER_DESC    "Generic USB ATM/DSL I/O, version " DRIVER_VERSION
+
+static const char usbatm_driver_name[] = "usbatm";
+
+#define UDSL_MAX_RCV_URBS              16
+#define UDSL_MAX_SND_URBS              16
+#define UDSL_MAX_BUF_SIZE              65536
+#define UDSL_DEFAULT_RCV_URBS          4
+#define UDSL_DEFAULT_SND_URBS          4
+#define UDSL_DEFAULT_RCV_BUF_SIZE      3392    /* 64 * ATM_CELL_SIZE */
+#define UDSL_DEFAULT_SND_BUF_SIZE      3392    /* 64 * ATM_CELL_SIZE */
+
+#define ATM_CELL_HEADER                        (ATM_CELL_SIZE - ATM_CELL_PAYLOAD)
+
+#define THROTTLE_MSECS                 100     /* delay to recover processing after urb submission fails */
+
+static unsigned int num_rcv_urbs = UDSL_DEFAULT_RCV_URBS;
+static unsigned int num_snd_urbs = UDSL_DEFAULT_SND_URBS;
+static unsigned int rcv_buf_bytes = UDSL_DEFAULT_RCV_BUF_SIZE;
+static unsigned int snd_buf_bytes = UDSL_DEFAULT_SND_BUF_SIZE;
+
+module_param(num_rcv_urbs, uint, S_IRUGO);
+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_param(num_snd_urbs, uint, S_IRUGO);
+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_param(rcv_buf_bytes, uint, S_IRUGO);
+MODULE_PARM_DESC(rcv_buf_bytes,
+                "Size of the buffers used for reception, in bytes (range: 1-"
+                __MODULE_STRING(UDSL_MAX_BUF_SIZE) ", default: "
+                __MODULE_STRING(UDSL_DEFAULT_RCV_BUF_SIZE) ")");
+
+module_param(snd_buf_bytes, uint, S_IRUGO);
+MODULE_PARM_DESC(snd_buf_bytes,
+                "Size of the buffers used for transmission, in bytes (range: 1-"
+                __MODULE_STRING(UDSL_MAX_BUF_SIZE) ", default: "
+                __MODULE_STRING(UDSL_DEFAULT_SND_BUF_SIZE) ")");
+
+
+/* receive */
+
+struct usbatm_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 usbatm_control {
+       struct atm_skb_data atm;
+       u32 len;
+       u32 crc;
+};
+
+#define UDSL_SKB(x)            ((struct usbatm_control *)(x)->cb)
+
+
+/* ATM */
+
+static void usbatm_atm_dev_close(struct atm_dev *atm_dev);
+static int usbatm_atm_open(struct atm_vcc *vcc);
+static void usbatm_atm_close(struct atm_vcc *vcc);
+static int usbatm_atm_ioctl(struct atm_dev *atm_dev, unsigned int cmd, void __user *arg);
+static int usbatm_atm_send(struct atm_vcc *vcc, struct sk_buff *skb);
+static int usbatm_atm_proc_read(struct atm_dev *atm_dev, loff_t *pos, char *page);
+
+static struct atmdev_ops usbatm_atm_devops = {
+       .dev_close      = usbatm_atm_dev_close,
+       .open           = usbatm_atm_open,
+       .close          = usbatm_atm_close,
+       .ioctl          = usbatm_atm_ioctl,
+       .send           = usbatm_atm_send,
+       .proc_read      = usbatm_atm_proc_read,
+       .owner          = THIS_MODULE,
+};
+
+
+/***********
+**  misc  **
+***********/
+
+static inline unsigned int usbatm_pdu_length(unsigned int length)
+{
+       length += ATM_CELL_PAYLOAD - 1 + ATM_AAL5_TRAILER;
+       return length - length % ATM_CELL_PAYLOAD;
+}
+
+static inline void usbatm_pop(struct atm_vcc *vcc, struct sk_buff *skb)
+{
+       if (vcc->pop)
+               vcc->pop(vcc, skb);
+       else
+               dev_kfree_skb_any(skb);
+}
+
+
+/***********
+**  urbs  **
+************/
+
+static struct urb *usbatm_pop_urb(struct usbatm_channel *channel)
+{
+       struct urb *urb;
+
+       spin_lock_irq(&channel->lock);
+       if (list_empty(&channel->list)) {
+               spin_unlock_irq(&channel->lock);
+               return NULL;
+       }
+
+       urb = list_entry(channel->list.next, struct urb, urb_list);
+       list_del(&urb->urb_list);
+       spin_unlock_irq(&channel->lock);
+
+       return urb;
+}
+
+static int usbatm_submit_urb(struct urb *urb)
+{
+       struct usbatm_channel *channel = urb->context;
+       int ret;
+
+       /* vdbg("%s: submitting urb 0x%p, size %u",
+            __func__, urb, urb->transfer_buffer_length); */
+
+       ret = usb_submit_urb(urb, GFP_ATOMIC);
+       if (ret) {
+               if (printk_ratelimit())
+                       atm_warn(channel->usbatm, "%s: urb 0x%p submission failed (%d)!\n",
+                               __func__, urb, ret);
+
+               /* consider all errors transient and return the buffer back to the queue */
+               urb->status = -EAGAIN;
+               spin_lock_irq(&channel->lock);
+
+               /* must add to the front when sending; doesn't matter when receiving */
+               list_add(&urb->urb_list, &channel->list);
+
+               spin_unlock_irq(&channel->lock);
+
+               /* make sure the channel doesn't stall */
+               mod_timer(&channel->delay, jiffies + msecs_to_jiffies(THROTTLE_MSECS));
+       }
+
+       return ret;
+}
+
+static void usbatm_complete(struct urb *urb)
+{
+       struct usbatm_channel *channel = urb->context;
+       unsigned long flags;
+       int status = urb->status;
+
+       /* vdbg("%s: urb 0x%p, status %d, actual_length %d",
+            __func__, urb, status, urb->actual_length); */
+
+       /* usually in_interrupt(), but not always */
+       spin_lock_irqsave(&channel->lock, flags);
+
+       /* must add to the back when receiving; doesn't matter when sending */
+       list_add_tail(&urb->urb_list, &channel->list);
+
+       spin_unlock_irqrestore(&channel->lock, flags);
+
+       if (unlikely(status) &&
+                       (!(channel->usbatm->flags & UDSL_IGNORE_EILSEQ) ||
+                        status != -EILSEQ)) {
+               if (status == -ESHUTDOWN)
+                       return;
+
+               if (printk_ratelimit())
+                       atm_warn(channel->usbatm, "%s: urb 0x%p failed (%d)!\n",
+                               __func__, urb, status);
+               /* throttle processing in case of an error */
+               mod_timer(&channel->delay, jiffies + msecs_to_jiffies(THROTTLE_MSECS));
+       } else
+               tasklet_schedule(&channel->tasklet);
+}
+
+
+/*************
+**  decode  **
+*************/
+
+static inline struct usbatm_vcc_data *usbatm_find_vcc(struct usbatm_data *instance,
+                                                 short vpi, int vci)
+{
+       struct usbatm_vcc_data *vcc_data;
+
+       list_for_each_entry(vcc_data, &instance->vcc_list, list)
+               if ((vcc_data->vci == vci) && (vcc_data->vpi == vpi))
+                       return vcc_data;
+       return NULL;
+}
+
+static void usbatm_extract_one_cell(struct usbatm_data *instance, unsigned char *source)
+{
+       struct atm_vcc *vcc;
+       struct sk_buff *sarb;
+       short vpi = ((source[0] & 0x0f) << 4)  | (source[1] >> 4);
+       int vci = ((source[1] & 0x0f) << 12) | (source[2] << 4) | (source[3] >> 4);
+       u8 pti = ((source[3] & 0xe) >> 1);
+
+       if ((vci != instance->cached_vci) || (vpi != instance->cached_vpi)) {
+               instance->cached_vpi = vpi;
+               instance->cached_vci = vci;
+
+               instance->cached_vcc = usbatm_find_vcc(instance, vpi, vci);
+
+               if (!instance->cached_vcc)
+                       atm_rldbg(instance, "%s: unknown vpi/vci (%hd/%d)!\n", __func__, vpi, vci);
+       }
+
+       if (!instance->cached_vcc)
+               return;
+
+       vcc = instance->cached_vcc->vcc;
+
+       /* OAM F5 end-to-end */
+       if (pti == ATM_PTI_E2EF5) {
+               if (printk_ratelimit())
+                       atm_warn(instance, "%s: OAM not supported (vpi %d, vci %d)!\n",
+                               __func__, vpi, vci);
+               atomic_inc(&vcc->stats->rx_err);
+               return;
+       }
+
+       sarb = instance->cached_vcc->sarb;
+
+       if (sarb->tail + ATM_CELL_PAYLOAD > sarb->end) {
+               atm_rldbg(instance, "%s: buffer overrun (sarb->len %u, vcc: 0x%p)!\n",
+                               __func__, sarb->len, vcc);
+               /* discard cells already received */
+               skb_trim(sarb, 0);
+       }
+
+       memcpy(skb_tail_pointer(sarb), source + ATM_CELL_HEADER, ATM_CELL_PAYLOAD);
+       __skb_put(sarb, ATM_CELL_PAYLOAD);
+
+       if (pti & 1) {
+               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) {
+                       atm_rldbg(instance, "%s: bogus length %u (vcc: 0x%p)!\n",
+                                 __func__, length, vcc);
+                       atomic_inc(&vcc->stats->rx_err);
+                       goto out;
+               }
+
+               pdu_length = usbatm_pdu_length(length);
+
+               if (sarb->len < pdu_length) {
+                       atm_rldbg(instance, "%s: bogus pdu_length %u (sarb->len: %u, vcc: 0x%p)!\n",
+                                 __func__, pdu_length, sarb->len, vcc);
+                       atomic_inc(&vcc->stats->rx_err);
+                       goto out;
+               }
+
+               if (crc32_be(~0, skb_tail_pointer(sarb) - pdu_length, pdu_length) != 0xc704dd7b) {
+                       atm_rldbg(instance, "%s: packet failed crc check (vcc: 0x%p)!\n",
+                                 __func__, vcc);
+                       atomic_inc(&vcc->stats->rx_err);
+                       goto out;
+               }
+
+               vdbg(&instance->usb_intf->dev,
+                    "%s: got packet (length: %u, pdu_length: %u, vcc: 0x%p)",
+                    __func__, length, pdu_length, vcc);
+
+               if (!(skb = dev_alloc_skb(length))) {
+                       if (printk_ratelimit())
+                               atm_err(instance, "%s: no memory for skb (length: %u)!\n",
+                                       __func__, length);
+                       atomic_inc(&vcc->stats->rx_drop);
+                       goto out;
+               }
+
+               vdbg(&instance->usb_intf->dev,
+                    "%s: allocated new sk_buff (skb: 0x%p, skb->truesize: %u)",
+                    __func__, skb, skb->truesize);
+
+               if (!atm_charge(vcc, skb->truesize)) {
+                       atm_rldbg(instance, "%s: failed atm_charge (skb->truesize: %u)!\n",
+                                 __func__, skb->truesize);
+                       dev_kfree_skb_any(skb);
+                       goto out;       /* atm_charge increments rx_drop */
+               }
+
+               skb_copy_to_linear_data(skb,
+                                       skb_tail_pointer(sarb) - pdu_length,
+                                       length);
+               __skb_put(skb, length);
+
+               vdbg(&instance->usb_intf->dev,
+                    "%s: sending skb 0x%p, skb->len %u, skb->truesize %u",
+                    __func__, skb, skb->len, skb->truesize);
+
+               PACKETDEBUG(instance, skb->data, skb->len);
+
+               vcc->push(vcc, skb);
+
+               atomic_inc(&vcc->stats->rx);
+       out:
+               skb_trim(sarb, 0);
+       }
+}
+
+static void usbatm_extract_cells(struct usbatm_data *instance,
+               unsigned char *source, unsigned int avail_data)
+{
+       unsigned int stride = instance->rx_channel.stride;
+       unsigned int buf_usage = instance->buf_usage;
+
+       /* extract cells from incoming data, taking into account that
+        * the length of avail data may not be a multiple of stride */
+
+       if (buf_usage > 0) {
+               /* we have a partially received atm cell */
+               unsigned char *cell_buf = instance->cell_buf;
+               unsigned int space_left = stride - buf_usage;
+
+               if (avail_data >= space_left) {
+                       /* add new data and process cell */
+                       memcpy(cell_buf + buf_usage, source, space_left);
+                       source += space_left;
+                       avail_data -= space_left;
+                       usbatm_extract_one_cell(instance, cell_buf);
+                       instance->buf_usage = 0;
+               } else {
+                       /* not enough data to fill the cell */
+                       memcpy(cell_buf + buf_usage, source, avail_data);
+                       instance->buf_usage = buf_usage + avail_data;
+                       return;
+               }
+       }
+
+       for (; avail_data >= stride; avail_data -= stride, source += stride)
+               usbatm_extract_one_cell(instance, source);
+
+       if (avail_data > 0) {
+               /* length was not a multiple of stride -
+                * save remaining data for next call */
+               memcpy(instance->cell_buf, source, avail_data);
+               instance->buf_usage = avail_data;
+       }
+}
+
+
+/*************
+**  encode  **
+*************/
+
+static unsigned int usbatm_write_cells(struct usbatm_data *instance,
+                                      struct sk_buff *skb,
+                                      u8 *target, unsigned int avail_space)
+{
+       struct usbatm_control *ctrl = UDSL_SKB(skb);
+       struct atm_vcc *vcc = ctrl->atm.vcc;
+       unsigned int bytes_written;
+       unsigned int stride = instance->tx_channel.stride;
+
+       for (bytes_written = 0; bytes_written < avail_space && ctrl->len;
+            bytes_written += stride, target += stride) {
+               unsigned int data_len = min_t(unsigned int, skb->len, ATM_CELL_PAYLOAD);
+               unsigned int left = ATM_CELL_PAYLOAD - data_len;
+               u8 *ptr = target;
+
+               ptr[0] = vcc->vpi >> 4;
+               ptr[1] = (vcc->vpi << 4) | (vcc->vci >> 12);
+               ptr[2] = vcc->vci >> 4;
+               ptr[3] = vcc->vci << 4;
+               ptr[4] = 0xec;
+               ptr += ATM_CELL_HEADER;
+
+               skb_copy_from_linear_data(skb, ptr, data_len);
+               ptr += data_len;
+               __skb_pull(skb, data_len);
+
+               if (!left)
+                       continue;
+
+               memset(ptr, 0, left);
+
+               if (left >= ATM_AAL5_TRAILER) { /* trailer will go in this cell */
+                       u8 *trailer = target + ATM_CELL_SIZE - ATM_AAL5_TRAILER;
+                       /* trailer[0] = 0;              UU = 0 */
+                       /* trailer[1] = 0;              CPI = 0 */
+                       trailer[2] = ctrl->len >> 8;
+                       trailer[3] = ctrl->len;
+
+                       ctrl->crc = ~crc32_be(ctrl->crc, ptr, left - 4);
+
+                       trailer[4] = ctrl->crc >> 24;
+                       trailer[5] = ctrl->crc >> 16;
+                       trailer[6] = ctrl->crc >> 8;
+                       trailer[7] = ctrl->crc;
+
+                       target[3] |= 0x2;       /* adjust PTI */
+
+                       ctrl->len = 0;          /* tag this skb finished */
+               } else
+                       ctrl->crc = crc32_be(ctrl->crc, ptr, left);
+       }
+
+       return bytes_written;
+}
+
+
+/**************
+**  receive  **
+**************/
+
+static void usbatm_rx_process(unsigned long data)
+{
+       struct usbatm_data *instance = (struct usbatm_data *)data;
+       struct urb *urb;
+
+       while ((urb = usbatm_pop_urb(&instance->rx_channel))) {
+               vdbg(&instance->usb_intf->dev,
+                    "%s: processing urb 0x%p", __func__, urb);
+
+               if (usb_pipeisoc(urb->pipe)) {
+                       unsigned char *merge_start = NULL;
+                       unsigned int merge_length = 0;
+                       const unsigned int packet_size = instance->rx_channel.packet_size;
+                       int i;
+
+                       for (i = 0; i < urb->number_of_packets; i++) {
+                               if (!urb->iso_frame_desc[i].status) {
+                                       unsigned int actual_length = urb->iso_frame_desc[i].actual_length;
+
+                                       if (!merge_length)
+                                               merge_start = (unsigned char *)urb->transfer_buffer + urb->iso_frame_desc[i].offset;
+                                       merge_length += actual_length;
+                                       if (merge_length && (actual_length < packet_size)) {
+                                               usbatm_extract_cells(instance, merge_start, merge_length);
+                                               merge_length = 0;
+                                       }
+                               } else {
+                                       atm_rldbg(instance, "%s: status %d in frame %d!\n", __func__, urb->status, i);
+                                       if (merge_length)
+                                               usbatm_extract_cells(instance, merge_start, merge_length);
+                                       merge_length = 0;
+                                       instance->buf_usage = 0;
+                               }
+                       }
+
+                       if (merge_length)
+                               usbatm_extract_cells(instance, merge_start, merge_length);
+               } else
+                       if (!urb->status)
+                               usbatm_extract_cells(instance, urb->transfer_buffer, urb->actual_length);
+                       else
+                               instance->buf_usage = 0;
+
+               if (usbatm_submit_urb(urb))
+                       return;
+       }
+}
+
+
+/***********
+**  send  **
+***********/
+
+static void usbatm_tx_process(unsigned long data)
+{
+       struct usbatm_data *instance = (struct usbatm_data *)data;
+       struct sk_buff *skb = instance->current_skb;
+       struct urb *urb = NULL;
+       const unsigned int buf_size = instance->tx_channel.buf_size;
+       unsigned int bytes_written = 0;
+       u8 *buffer = NULL;
+
+       if (!skb)
+               skb = skb_dequeue(&instance->sndqueue);
+
+       while (skb) {
+               if (!urb) {
+                       urb = usbatm_pop_urb(&instance->tx_channel);
+                       if (!urb)
+                               break;          /* no more senders */
+                       buffer = urb->transfer_buffer;
+                       bytes_written = (urb->status == -EAGAIN) ?
+                               urb->transfer_buffer_length : 0;
+               }
+
+               bytes_written += usbatm_write_cells(instance, skb,
+                                                 buffer + bytes_written,
+                                                 buf_size - bytes_written);
+
+               vdbg(&instance->usb_intf->dev,
+                    "%s: wrote %u bytes from skb 0x%p to urb 0x%p",
+                    __func__, bytes_written, skb, urb);
+
+               if (!UDSL_SKB(skb)->len) {
+                       struct atm_vcc *vcc = UDSL_SKB(skb)->atm.vcc;
+
+                       usbatm_pop(vcc, skb);
+                       atomic_inc(&vcc->stats->tx);
+
+                       skb = skb_dequeue(&instance->sndqueue);
+               }
+
+               if (bytes_written == buf_size || (!skb && bytes_written)) {
+                       urb->transfer_buffer_length = bytes_written;
+
+                       if (usbatm_submit_urb(urb))
+                               break;
+                       urb = NULL;
+               }
+       }
+
+       instance->current_skb = skb;
+}
+
+static void usbatm_cancel_send(struct usbatm_data *instance,
+                              struct atm_vcc *vcc)
+{
+       struct sk_buff *skb, *n;
+
+       spin_lock_irq(&instance->sndqueue.lock);
+       skb_queue_walk_safe(&instance->sndqueue, skb, n) {
+               if (UDSL_SKB(skb)->atm.vcc == vcc) {
+                       atm_dbg(instance, "%s: popping skb 0x%p\n", __func__, skb);
+                       __skb_unlink(skb, &instance->sndqueue);
+                       usbatm_pop(vcc, skb);
+               }
+       }
+       spin_unlock_irq(&instance->sndqueue.lock);
+
+       tasklet_disable(&instance->tx_channel.tasklet);
+       if ((skb = instance->current_skb) && (UDSL_SKB(skb)->atm.vcc == vcc)) {
+               atm_dbg(instance, "%s: popping current skb (0x%p)\n", __func__, skb);
+               instance->current_skb = NULL;
+               usbatm_pop(vcc, skb);
+       }
+       tasklet_enable(&instance->tx_channel.tasklet);
+}
+
+static int usbatm_atm_send(struct atm_vcc *vcc, struct sk_buff *skb)
+{
+       struct usbatm_data *instance = vcc->dev->dev_data;
+       struct usbatm_control *ctrl = UDSL_SKB(skb);
+       int err;
+
+       /* racy disconnection check - fine */
+       if (!instance || instance->disconnected) {
+#ifdef VERBOSE_DEBUG
+               printk_ratelimited(KERN_DEBUG "%s: %s!\n", __func__, instance ? "disconnected" : "NULL instance");
+#endif
+               err = -ENODEV;
+               goto fail;
+       }
+
+       if (vcc->qos.aal != ATM_AAL5) {
+               atm_rldbg(instance, "%s: unsupported ATM type %d!\n", __func__, vcc->qos.aal);
+               err = -EINVAL;
+               goto fail;
+       }
+
+       if (skb->len > ATM_MAX_AAL5_PDU) {
+               atm_rldbg(instance, "%s: packet too long (%d vs %d)!\n",
+                               __func__, skb->len, ATM_MAX_AAL5_PDU);
+               err = -EINVAL;
+               goto fail;
+       }
+
+       PACKETDEBUG(instance, skb->data, skb->len);
+
+       /* initialize the control block */
+       ctrl->atm.vcc = vcc;
+       ctrl->len = skb->len;
+       ctrl->crc = crc32_be(~0, skb->data, skb->len);
+
+       skb_queue_tail(&instance->sndqueue, skb);
+       tasklet_schedule(&instance->tx_channel.tasklet);
+
+       return 0;
+
+ fail:
+       usbatm_pop(vcc, skb);
+       return err;
+}
+
+
+/********************
+**  bean counting  **
+********************/
+
+static void usbatm_destroy_instance(struct kref *kref)
+{
+       struct usbatm_data *instance = container_of(kref, struct usbatm_data, refcount);
+
+       tasklet_kill(&instance->rx_channel.tasklet);
+       tasklet_kill(&instance->tx_channel.tasklet);
+       usb_put_dev(instance->usb_dev);
+       kfree(instance);
+}
+
+static void usbatm_get_instance(struct usbatm_data *instance)
+{
+       kref_get(&instance->refcount);
+}
+
+static void usbatm_put_instance(struct usbatm_data *instance)
+{
+       kref_put(&instance->refcount, usbatm_destroy_instance);
+}
+
+
+/**********
+**  ATM  **
+**********/
+
+static void usbatm_atm_dev_close(struct atm_dev *atm_dev)
+{
+       struct usbatm_data *instance = atm_dev->dev_data;
+
+       if (!instance)
+               return;
+
+       atm_dev->dev_data = NULL; /* catch bugs */
+       usbatm_put_instance(instance);  /* taken in usbatm_atm_init */
+}
+
+static int usbatm_atm_proc_read(struct atm_dev *atm_dev, loff_t *pos, char *page)
+{
+       struct usbatm_data *instance = atm_dev->dev_data;
+       int left = *pos;
+
+       if (!instance)
+               return -ENODEV;
+
+       if (!left--)
+               return sprintf(page, "%s\n", instance->description);
+
+       if (!left--)
+               return sprintf(page, "MAC: %pM\n", atm_dev->esi);
+
+       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--) {
+               if (instance->disconnected)
+                       return sprintf(page, "Disconnected\n");
+               else
+                       switch (atm_dev->signal) {
+                       case ATM_PHY_SIG_FOUND:
+                               return sprintf(page, "Line up\n");
+                       case ATM_PHY_SIG_LOST:
+                               return sprintf(page, "Line down\n");
+                       default:
+                               return sprintf(page, "Line state unknown\n");
+                       }
+       }
+
+       return 0;
+}
+
+static int usbatm_atm_open(struct atm_vcc *vcc)
+{
+       struct usbatm_data *instance = vcc->dev->dev_data;
+       struct usbatm_vcc_data *new = NULL;
+       int ret;
+       int vci = vcc->vci;
+       short vpi = vcc->vpi;
+
+       if (!instance)
+               return -ENODEV;
+
+       /* only support AAL5 */
+       if ((vcc->qos.aal != ATM_AAL5)) {
+               atm_warn(instance, "%s: unsupported ATM type %d!\n", __func__, vcc->qos.aal);
+               return -EINVAL;
+       }
+
+       /* sanity checks */
+       if ((vcc->qos.rxtp.max_sdu < 0) || (vcc->qos.rxtp.max_sdu > ATM_MAX_AAL5_PDU)) {
+               atm_dbg(instance, "%s: max_sdu %d out of range!\n", __func__, vcc->qos.rxtp.max_sdu);
+               return -EINVAL;
+       }
+
+       mutex_lock(&instance->serialize);       /* vs self, usbatm_atm_close, usbatm_usb_disconnect */
+
+       if (instance->disconnected) {
+               atm_dbg(instance, "%s: disconnected!\n", __func__);
+               ret = -ENODEV;
+               goto fail;
+       }
+
+       if (usbatm_find_vcc(instance, vpi, vci)) {
+               atm_dbg(instance, "%s: %hd/%d already in use!\n", __func__, vpi, vci);
+               ret = -EADDRINUSE;
+               goto fail;
+       }
+
+       if (!(new = kzalloc(sizeof(struct usbatm_vcc_data), GFP_KERNEL))) {
+               atm_err(instance, "%s: no memory for vcc_data!\n", __func__);
+               ret = -ENOMEM;
+               goto fail;
+       }
+
+       new->vcc = vcc;
+       new->vpi = vpi;
+       new->vci = vci;
+
+       new->sarb = alloc_skb(usbatm_pdu_length(vcc->qos.rxtp.max_sdu), GFP_KERNEL);
+       if (!new->sarb) {
+               atm_err(instance, "%s: no memory for SAR buffer!\n", __func__);
+               ret = -ENOMEM;
+               goto fail;
+       }
+
+       vcc->dev_data = new;
+
+       tasklet_disable(&instance->rx_channel.tasklet);
+       instance->cached_vcc = new;
+       instance->cached_vpi = vpi;
+       instance->cached_vci = vci;
+       list_add(&new->list, &instance->vcc_list);
+       tasklet_enable(&instance->rx_channel.tasklet);
+
+       set_bit(ATM_VF_ADDR, &vcc->flags);
+       set_bit(ATM_VF_PARTIAL, &vcc->flags);
+       set_bit(ATM_VF_READY, &vcc->flags);
+
+       mutex_unlock(&instance->serialize);
+
+       atm_dbg(instance, "%s: allocated vcc data 0x%p\n", __func__, new);
+
+       return 0;
+
+fail:
+       kfree(new);
+       mutex_unlock(&instance->serialize);
+       return ret;
+}
+
+static void usbatm_atm_close(struct atm_vcc *vcc)
+{
+       struct usbatm_data *instance = vcc->dev->dev_data;
+       struct usbatm_vcc_data *vcc_data = vcc->dev_data;
+
+       if (!instance || !vcc_data)
+               return;
+
+       usbatm_cancel_send(instance, vcc);
+
+       mutex_lock(&instance->serialize);       /* vs self, usbatm_atm_open, usbatm_usb_disconnect */
+
+       tasklet_disable(&instance->rx_channel.tasklet);
+       if (instance->cached_vcc == vcc_data) {
+               instance->cached_vcc = NULL;
+               instance->cached_vpi = ATM_VPI_UNSPEC;
+               instance->cached_vci = ATM_VCI_UNSPEC;
+       }
+       list_del(&vcc_data->list);
+       tasklet_enable(&instance->rx_channel.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);
+
+       mutex_unlock(&instance->serialize);
+}
+
+static int usbatm_atm_ioctl(struct atm_dev *atm_dev, unsigned int cmd,
+                         void __user *arg)
+{
+       struct usbatm_data *instance = atm_dev->dev_data;
+
+       if (!instance || instance->disconnected)
+               return -ENODEV;
+
+       switch (cmd) {
+       case ATM_QUERYLOOP:
+               return put_user(ATM_LM_NONE, (int __user *)arg) ? -EFAULT : 0;
+       default:
+               return -ENOIOCTLCMD;
+       }
+}
+
+static int usbatm_atm_init(struct usbatm_data *instance)
+{
+       struct atm_dev *atm_dev;
+       int ret, i;
+
+       /* ATM init.  The ATM initialization scheme suffers from an intrinsic race
+        * condition: callbacks we register can be executed at once, before we have
+        * initialized the struct atm_dev.  To protect against this, all callbacks
+        * abort if atm_dev->dev_data is NULL. */
+       atm_dev = atm_dev_register(instance->driver_name,
+                                  &instance->usb_intf->dev, &usbatm_atm_devops,
+                                  -1, NULL);
+       if (!atm_dev) {
+               usb_err(instance, "%s: failed to register ATM device!\n", __func__);
+               return -1;
+       }
+
+       instance->atm_dev = atm_dev;
+
+       atm_dev->ci_range.vpi_bits = ATM_CI_MAX;
+       atm_dev->ci_range.vci_bits = ATM_CI_MAX;
+       atm_dev->signal = ATM_PHY_SIG_UNKNOWN;
+
+       /* temp init ATM device, set to 128kbit */
+       atm_dev->link_rate = 128 * 1000 / 424;
+
+       if (instance->driver->atm_start && ((ret = instance->driver->atm_start(instance, atm_dev)) < 0)) {
+               atm_err(instance, "%s: atm_start failed: %d!\n", __func__, ret);
+               goto fail;
+       }
+
+       usbatm_get_instance(instance);  /* dropped in usbatm_atm_dev_close */
+
+       /* ready for ATM callbacks */
+       mb();
+       atm_dev->dev_data = instance;
+
+       /* submit all rx URBs */
+       for (i = 0; i < num_rcv_urbs; i++)
+               usbatm_submit_urb(instance->urbs[i]);
+
+       return 0;
+
+ fail:
+       instance->atm_dev = NULL;
+       atm_dev_deregister(atm_dev); /* usbatm_atm_dev_close will eventually be called */
+       return ret;
+}
+
+
+/**********
+**  USB  **
+**********/
+
+static int usbatm_do_heavy_init(void *arg)
+{
+       struct usbatm_data *instance = arg;
+       int ret;
+
+       allow_signal(SIGTERM);
+       complete(&instance->thread_started);
+
+       ret = instance->driver->heavy_init(instance, instance->usb_intf);
+
+       if (!ret)
+               ret = usbatm_atm_init(instance);
+
+       mutex_lock(&instance->serialize);
+       instance->thread = NULL;
+       mutex_unlock(&instance->serialize);
+
+       complete_and_exit(&instance->thread_exited, ret);
+}
+
+static int usbatm_heavy_init(struct usbatm_data *instance)
+{
+       struct task_struct *t;
+
+       t = kthread_create(usbatm_do_heavy_init, instance, "%s",
+                       instance->driver->driver_name);
+       if (IS_ERR(t)) {
+               usb_err(instance, "%s: failed to create kernel_thread (%ld)!\n",
+                               __func__, PTR_ERR(t));
+               return PTR_ERR(t);
+       }
+
+       instance->thread = t;
+       wake_up_process(t);
+       wait_for_completion(&instance->thread_started);
+
+       return 0;
+}
+
+static void usbatm_tasklet_schedule(unsigned long data)
+{
+       tasklet_schedule((struct tasklet_struct *) data);
+}
+
+static void usbatm_init_channel(struct usbatm_channel *channel)
+{
+       spin_lock_init(&channel->lock);
+       INIT_LIST_HEAD(&channel->list);
+       channel->delay.function = usbatm_tasklet_schedule;
+       channel->delay.data = (unsigned long) &channel->tasklet;
+       init_timer(&channel->delay);
+}
+
+int usbatm_usb_probe(struct usb_interface *intf, const struct usb_device_id *id,
+                    struct usbatm_driver *driver)
+{
+       struct device *dev = &intf->dev;
+       struct usb_device *usb_dev = interface_to_usbdev(intf);
+       struct usbatm_data *instance;
+       char *buf;
+       int error = -ENOMEM;
+       int i, length;
+       unsigned int maxpacket, num_packets;
+
+       /* instance init */
+       instance = kzalloc(sizeof(*instance) + sizeof(struct urb *) * (num_rcv_urbs + num_snd_urbs), GFP_KERNEL);
+       if (!instance) {
+               dev_err(dev, "%s: no memory for instance data!\n", __func__);
+               return -ENOMEM;
+       }
+
+       /* public fields */
+
+       instance->driver = driver;
+       strlcpy(instance->driver_name, driver->driver_name,
+               sizeof(instance->driver_name));
+
+       instance->usb_dev = usb_dev;
+       instance->usb_intf = intf;
+
+       buf = instance->description;
+       length = sizeof(instance->description);
+
+       if ((i = usb_string(usb_dev, usb_dev->descriptor.iProduct, buf, length)) < 0)
+               goto bind;
+
+       buf += i;
+       length -= i;
+
+       i = scnprintf(buf, length, " (");
+       buf += i;
+       length -= i;
+
+       if (length <= 0 || (i = usb_make_path(usb_dev, buf, length)) < 0)
+               goto bind;
+
+       buf += i;
+       length -= i;
+
+       snprintf(buf, length, ")");
+
+ bind:
+       if (driver->bind && (error = driver->bind(instance, intf, id)) < 0) {
+                       dev_err(dev, "%s: bind failed: %d!\n", __func__, error);
+                       goto fail_free;
+       }
+
+       /* private fields */
+
+       kref_init(&instance->refcount);         /* dropped in usbatm_usb_disconnect */
+       mutex_init(&instance->serialize);
+
+       instance->thread = NULL;
+       init_completion(&instance->thread_started);
+       init_completion(&instance->thread_exited);
+
+       INIT_LIST_HEAD(&instance->vcc_list);
+       skb_queue_head_init(&instance->sndqueue);
+
+       usbatm_init_channel(&instance->rx_channel);
+       usbatm_init_channel(&instance->tx_channel);
+       tasklet_init(&instance->rx_channel.tasklet, usbatm_rx_process, (unsigned long)instance);
+       tasklet_init(&instance->tx_channel.tasklet, usbatm_tx_process, (unsigned long)instance);
+       instance->rx_channel.stride = ATM_CELL_SIZE + driver->rx_padding;
+       instance->tx_channel.stride = ATM_CELL_SIZE + driver->tx_padding;
+       instance->rx_channel.usbatm = instance->tx_channel.usbatm = instance;
+
+       if ((instance->flags & UDSL_USE_ISOC) && driver->isoc_in)
+               instance->rx_channel.endpoint = usb_rcvisocpipe(usb_dev, driver->isoc_in);
+       else
+               instance->rx_channel.endpoint = usb_rcvbulkpipe(usb_dev, driver->bulk_in);
+
+       instance->tx_channel.endpoint = usb_sndbulkpipe(usb_dev, driver->bulk_out);
+
+       /* tx buffer size must be a positive multiple of the stride */
+       instance->tx_channel.buf_size = max(instance->tx_channel.stride,
+                       snd_buf_bytes - (snd_buf_bytes % instance->tx_channel.stride));
+
+       /* rx buffer size must be a positive multiple of the endpoint maxpacket */
+       maxpacket = usb_maxpacket(usb_dev, instance->rx_channel.endpoint, 0);
+
+       if ((maxpacket < 1) || (maxpacket > UDSL_MAX_BUF_SIZE)) {
+               dev_err(dev, "%s: invalid endpoint %02x!\n", __func__,
+                               usb_pipeendpoint(instance->rx_channel.endpoint));
+               error = -EINVAL;
+               goto fail_unbind;
+       }
+
+       num_packets = max(1U, (rcv_buf_bytes + maxpacket / 2) / maxpacket); /* round */
+
+       if (num_packets * maxpacket > UDSL_MAX_BUF_SIZE)
+               num_packets--;
+
+       instance->rx_channel.buf_size = num_packets * maxpacket;
+       instance->rx_channel.packet_size = maxpacket;
+
+       for (i = 0; i < 2; i++) {
+               struct usbatm_channel *channel = i ?
+                       &instance->tx_channel : &instance->rx_channel;
+
+               dev_dbg(dev, "%s: using %d byte buffer for %s channel 0x%p\n",
+                       __func__, channel->buf_size, i ? "tx" : "rx", channel);
+       }
+
+       /* initialize urbs */
+
+       for (i = 0; i < num_rcv_urbs + num_snd_urbs; i++) {
+               u8 *buffer;
+               struct usbatm_channel *channel = i < num_rcv_urbs ?
+                       &instance->rx_channel : &instance->tx_channel;
+               struct urb *urb;
+               unsigned int iso_packets = usb_pipeisoc(channel->endpoint) ? channel->buf_size / channel->packet_size : 0;
+
+               urb = usb_alloc_urb(iso_packets, GFP_KERNEL);
+               if (!urb) {
+                       dev_err(dev, "%s: no memory for urb %d!\n", __func__, i);
+                       error = -ENOMEM;
+                       goto fail_unbind;
+               }
+
+               instance->urbs[i] = urb;
+
+               /* zero the tx padding to avoid leaking information */
+               buffer = kzalloc(channel->buf_size, GFP_KERNEL);
+               if (!buffer) {
+                       dev_err(dev, "%s: no memory for buffer %d!\n", __func__, i);
+                       error = -ENOMEM;
+                       goto fail_unbind;
+               }
+
+               usb_fill_bulk_urb(urb, instance->usb_dev, channel->endpoint,
+                                 buffer, channel->buf_size, usbatm_complete, channel);
+               if (iso_packets) {
+                       int j;
+                       urb->interval = 1;
+                       urb->transfer_flags = URB_ISO_ASAP;
+                       urb->number_of_packets = iso_packets;
+                       for (j = 0; j < iso_packets; j++) {
+                               urb->iso_frame_desc[j].offset = channel->packet_size * j;
+                               urb->iso_frame_desc[j].length = channel->packet_size;
+                       }
+               }
+
+               /* put all tx URBs on the list of spares */
+               if (i >= num_rcv_urbs)
+                       list_add_tail(&urb->urb_list, &channel->list);
+
+               vdbg(&intf->dev, "%s: alloced buffer 0x%p buf size %u urb 0x%p",
+                    __func__, urb->transfer_buffer, urb->transfer_buffer_length, urb);
+       }
+
+       instance->cached_vpi = ATM_VPI_UNSPEC;
+       instance->cached_vci = ATM_VCI_UNSPEC;
+       instance->cell_buf = kmalloc(instance->rx_channel.stride, GFP_KERNEL);
+
+       if (!instance->cell_buf) {
+               dev_err(dev, "%s: no memory for cell buffer!\n", __func__);
+               error = -ENOMEM;
+               goto fail_unbind;
+       }
+
+       if (!(instance->flags & UDSL_SKIP_HEAVY_INIT) && driver->heavy_init) {
+               error = usbatm_heavy_init(instance);
+       } else {
+               complete(&instance->thread_exited);     /* pretend that heavy_init was run */
+               error = usbatm_atm_init(instance);
+       }
+
+       if (error < 0)
+               goto fail_unbind;
+
+       usb_get_dev(usb_dev);
+       usb_set_intfdata(intf, instance);
+
+       return 0;
+
+ fail_unbind:
+       if (instance->driver->unbind)
+               instance->driver->unbind(instance, intf);
+ fail_free:
+       kfree(instance->cell_buf);
+
+       for (i = 0; i < num_rcv_urbs + num_snd_urbs; i++) {
+               if (instance->urbs[i])
+                       kfree(instance->urbs[i]->transfer_buffer);
+               usb_free_urb(instance->urbs[i]);
+       }
+
+       kfree(instance);
+
+       return error;
+}
+EXPORT_SYMBOL_GPL(usbatm_usb_probe);
+
+void usbatm_usb_disconnect(struct usb_interface *intf)
+{
+       struct device *dev = &intf->dev;
+       struct usbatm_data *instance = usb_get_intfdata(intf);
+       struct usbatm_vcc_data *vcc_data;
+       int i;
+
+       if (!instance) {
+               dev_dbg(dev, "%s: NULL instance!\n", __func__);
+               return;
+       }
+
+       usb_set_intfdata(intf, NULL);
+
+       mutex_lock(&instance->serialize);
+       instance->disconnected = 1;
+       if (instance->thread != NULL)
+               send_sig(SIGTERM, instance->thread, 1);
+       mutex_unlock(&instance->serialize);
+
+       wait_for_completion(&instance->thread_exited);
+
+       mutex_lock(&instance->serialize);
+       list_for_each_entry(vcc_data, &instance->vcc_list, list)
+               vcc_release_async(vcc_data->vcc, -EPIPE);
+       mutex_unlock(&instance->serialize);
+
+       tasklet_disable(&instance->rx_channel.tasklet);
+       tasklet_disable(&instance->tx_channel.tasklet);
+
+       for (i = 0; i < num_rcv_urbs + num_snd_urbs; i++)
+               usb_kill_urb(instance->urbs[i]);
+
+       del_timer_sync(&instance->rx_channel.delay);
+       del_timer_sync(&instance->tx_channel.delay);
+
+       /* turn usbatm_[rt]x_process into something close to a no-op */
+       /* no need to take the spinlock */
+       INIT_LIST_HEAD(&instance->rx_channel.list);
+       INIT_LIST_HEAD(&instance->tx_channel.list);
+
+       tasklet_enable(&instance->rx_channel.tasklet);
+       tasklet_enable(&instance->tx_channel.tasklet);
+
+       if (instance->atm_dev && instance->driver->atm_stop)
+               instance->driver->atm_stop(instance, instance->atm_dev);
+
+       if (instance->driver->unbind)
+               instance->driver->unbind(instance, intf);
+
+       instance->driver_data = NULL;
+
+       for (i = 0; i < num_rcv_urbs + num_snd_urbs; i++) {
+               kfree(instance->urbs[i]->transfer_buffer);
+               usb_free_urb(instance->urbs[i]);
+       }
+
+       kfree(instance->cell_buf);
+
+       /* ATM finalize */
+       if (instance->atm_dev) {
+               atm_dev_deregister(instance->atm_dev);
+               instance->atm_dev = NULL;
+       }
+
+       usbatm_put_instance(instance);  /* taken in usbatm_usb_probe */
+}
+EXPORT_SYMBOL_GPL(usbatm_usb_disconnect);
+
+
+/***********
+**  init  **
+***********/
+
+static int __init usbatm_usb_init(void)
+{
+       if (sizeof(struct usbatm_control) > FIELD_SIZEOF(struct sk_buff, cb)) {
+               printk(KERN_ERR "%s unusable with this kernel!\n", usbatm_driver_name);
+               return -EIO;
+       }
+
+       if ((num_rcv_urbs > UDSL_MAX_RCV_URBS)
+           || (num_snd_urbs > UDSL_MAX_SND_URBS)
+           || (rcv_buf_bytes < 1)
+           || (rcv_buf_bytes > UDSL_MAX_BUF_SIZE)
+           || (snd_buf_bytes < 1)
+           || (snd_buf_bytes > UDSL_MAX_BUF_SIZE))
+               return -EINVAL;
+
+       return 0;
+}
+module_init(usbatm_usb_init);
+
+static void __exit usbatm_usb_exit(void)
+{
+}
+module_exit(usbatm_usb_exit);
+
+MODULE_AUTHOR(DRIVER_AUTHOR);
+MODULE_DESCRIPTION(DRIVER_DESC);
+MODULE_LICENSE("GPL");
+MODULE_VERSION(DRIVER_VERSION);
+
+/************
+**  debug  **
+************/
+
+#ifdef VERBOSE_DEBUG
+static int usbatm_print_packet(struct usbatm_data *instance,
+                              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]);
+               dev_dbg(&instance->usb_intf->dev, "%s", buffer);
+       }
+       return i;
+}
+#endif