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usbatm.c

/******************************************************************************
 *  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>

#ifdef VERBOSE_DEBUG
static int usbatm_print_packet(const unsigned char *data, int len);
#define PACKETDEBUG(arg...)   usbatm_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  "1.10"
#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);

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

      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);
            UDSL_ASSERT(sarb->tail + ATM_CELL_PAYLOAD <= sarb->end);
      }

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

            PACKETDEBUG(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;

            UDSL_ASSERT(buf_usage <= stride);

            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;

      vdbg("%s: skb->len=%d, avail_space=%u", __func__, skb->len, avail_space);
      UDSL_ASSERT(!(avail_space % 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("%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;

                              UDSL_ASSERT(actual_length <= packet_size);

                              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("%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;

      atm_dbg(instance, "%s entered\n", __func__);
      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.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);
      atm_dbg(instance, "%s done\n", __func__);
}

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;

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

      /* racy disconnection check - fine */
      if (!instance || instance->disconnected) {
#ifdef DEBUG
            if (printk_ratelimit())
                  printk(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(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);

      dbg("%s", __func__);

      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)
{
      dbg("%s", __func__);

      kref_get(&instance->refcount);
}

static void usbatm_put_instance(struct usbatm_data *instance)
{
      dbg("%s", __func__);

      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;

      dbg("%s", __func__);

      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) {
            dbg("%s: NULL instance!", __func__);
            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--) {
            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) {
            dbg("%s: NULL data!", __func__);
            return -ENODEV;
      }

      atm_dbg(instance, "%s: vpi %hd, vci %d\n", __func__, vpi, vci);

      /* 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) {
            dbg("%s: NULL data!", __func__);
            return;
      }

      atm_dbg(instance, "%s entered\n", __func__);

      atm_dbg(instance, "%s: deallocating vcc 0x%p with vpi %d vci %d\n",
            __func__, vcc_data, vcc_data->vpi, vcc_data->vci);

      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);

      atm_dbg(instance, "%s successful\n", __func__);
}

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) {
            dbg("%s: %s!", __func__, instance ? "disconnected" : "NULL instance");
            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, &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;

      ret = sysfs_create_link(&atm_dev->class_dev.kobj,
                        &instance->usb_intf->dev.kobj, "device");
      if (ret) {
            atm_err(instance, "%s: sysfs_create_link failed: %d\n",
                              __func__, ret);
            goto fail_sysfs;
      }

      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:
      sysfs_remove_link(&atm_dev->class_dev.kobj, "device");
 fail_sysfs:
      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;

      daemonize(instance->driver->driver_name);
      allow_signal(SIGTERM);
      instance->thread_pid = current->pid;

      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_pid = -1;
      mutex_unlock(&instance->serialize);

      complete_and_exit(&instance->thread_exited, ret);
}

static int usbatm_heavy_init(struct usbatm_data *instance)
{
      int ret = kernel_thread(usbatm_do_heavy_init, instance, CLONE_FS | CLONE_FILES);

      if (ret < 0) {
            usb_err(instance, "%s: failed to create kernel_thread (%d)!\n", __func__, ret);
            return ret;
      }

      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;

      dev_dbg(dev, "%s: trying driver %s with vendor=%04x, product=%04x, ifnum %2d\n",
                  __func__, driver->driver_name,
                  le16_to_cpu(usb_dev->descriptor.idVendor),
                  le16_to_cpu(usb_dev->descriptor.idProduct),
                  intf->altsetting->desc.bInterfaceNumber);

      /* 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;
      snprintf(instance->driver_name, sizeof(instance->driver_name), driver->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_pid = -1;
      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;

#ifdef DEBUG
      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);
      }
#endif

      /* 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;

            UDSL_ASSERT(!usb_pipeisoc(channel->endpoint) || usb_pipein(channel->endpoint));

            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("%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;

      dev_dbg(dev, "%s entered\n", __func__);

      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_pid >= 0)
            kill_proc(instance->thread_pid, SIGTERM, 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) {
            sysfs_remove_link(&instance->atm_dev->class_dev.kobj, "device");
            atm_dev_deregister(instance->atm_dev);
      }

      usbatm_put_instance(instance);      /* taken in usbatm_usb_probe */
}
EXPORT_SYMBOL_GPL(usbatm_usb_disconnect);


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

static int __init usbatm_usb_init(void)
{
      dbg("%s: driver version %s", __func__, DRIVER_VERSION);

      if (sizeof(struct usbatm_control) > sizeof(((struct sk_buff *) 0)->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)
{
      dbg("%s", __func__);
}
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(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

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