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capi.c

/* $Id: capi.c,v 1.1.2.7 2004/04/28 09:48:59 armin Exp $
 *
 * CAPI 2.0 Interface for Linux
 *
 * Copyright 1996 by Carsten Paeth <calle@calle.de>
 *
 * This software may be used and distributed according to the terms
 * of the GNU General Public License, incorporated herein by reference.
 *
 */

#include <linux/module.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/major.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/fcntl.h>
#include <linux/fs.h>
#include <linux/signal.h>
#include <linux/mutex.h>
#include <linux/mm.h>
#include <linux/timer.h>
#include <linux/wait.h>
#ifdef CONFIG_ISDN_CAPI_MIDDLEWARE
#include <linux/tty.h>
#ifdef CONFIG_PPP
#include <linux/netdevice.h>
#include <linux/ppp_defs.h>
#include <linux/if_ppp.h>
#endif /* CONFIG_PPP */
#endif /* CONFIG_ISDN_CAPI_MIDDLEWARE */
#include <linux/skbuff.h>
#include <linux/proc_fs.h>
#include <linux/poll.h>
#include <linux/capi.h>
#include <linux/kernelcapi.h>
#include <linux/init.h>
#include <linux/device.h>
#include <linux/moduleparam.h>
#include <linux/isdn/capiutil.h>
#include <linux/isdn/capicmd.h>
#if defined(CONFIG_ISDN_CAPI_CAPIFS) || defined(CONFIG_ISDN_CAPI_CAPIFS_MODULE)
#include "capifs.h"
#endif

static char *revision = "$Revision: 1.1.2.7 $";

MODULE_DESCRIPTION("CAPI4Linux: Userspace /dev/capi20 interface");
MODULE_AUTHOR("Carsten Paeth");
MODULE_LICENSE("GPL");

#undef _DEBUG_REFCOUNT        /* alloc/free and open/close debug */
#undef _DEBUG_TTYFUNCS        /* call to tty_driver */
#undef _DEBUG_DATAFLOW        /* data flow */

/* -------- driver information -------------------------------------- */

static struct class *capi_class;

static int capi_major = 68;         /* allocated */
#ifdef CONFIG_ISDN_CAPI_MIDDLEWARE
#define CAPINC_NR_PORTS 32
#define CAPINC_MAX_PORTS      256
static int capi_ttymajor = 191;
static int capi_ttyminors = CAPINC_NR_PORTS;
#endif /* CONFIG_ISDN_CAPI_MIDDLEWARE */

module_param_named(major, capi_major, uint, 0);
#ifdef CONFIG_ISDN_CAPI_MIDDLEWARE
module_param_named(ttymajor, capi_ttymajor, uint, 0);
module_param_named(ttyminors, capi_ttyminors, uint, 0);
#endif /* CONFIG_ISDN_CAPI_MIDDLEWARE */

/* -------- defines ------------------------------------------------- */

#define CAPINC_MAX_RECVQUEUE  10
#define CAPINC_MAX_SENDQUEUE  10
#define CAPI_MAX_BLKSIZE      2048

/* -------- data structures ----------------------------------------- */

struct capidev;
struct capincci;
#ifdef CONFIG_ISDN_CAPI_MIDDLEWARE
struct capiminor;

struct datahandle_queue {
      struct list_head  list;
      u16               datahandle;
};

struct capiminor {
      struct list_head list;
      struct capincci  *nccip;
      unsigned int      minor;

      struct capi20_appl *ap;
      u32          ncci;
      u16          datahandle;
      u16          msgid;

      struct tty_struct *tty;
      int                ttyinstop;
      int                ttyoutstop;
      struct sk_buff    *ttyskb;
      atomic_t           ttyopencount;

      struct sk_buff_head inqueue;
      int                 inbytes;
      struct sk_buff_head outqueue;
      int                 outbytes;

      /* transmit path */
      struct list_head ackqueue;
      int nack;
      spinlock_t ackqlock;
};
#endif /* CONFIG_ISDN_CAPI_MIDDLEWARE */

/* FIXME: The following lock is a sledgehammer-workaround to a
 * locking issue with the capiminor (and maybe other) data structure(s).
 * Access to this data is done in a racy way and crashes the machine with
 * a FritzCard DSL driver; sooner or later. This is a workaround
 * which trades scalability vs stability, so it doesn't crash the kernel anymore.
 * The correct (and scalable) fix for the issue seems to require
 * an API change to the drivers... . */
static DEFINE_SPINLOCK(workaround_lock);

struct capincci {
      struct capincci *next;
      u32          ncci;
      struct capidev    *cdev;
#ifdef CONFIG_ISDN_CAPI_MIDDLEWARE
      struct capiminor *minorp;
#endif /* CONFIG_ISDN_CAPI_MIDDLEWARE */
};

struct capidev {
      struct list_head list;
      struct capi20_appl ap;
      u16         errcode;
      unsigned        userflags;

      struct sk_buff_head recvqueue;
      wait_queue_head_t recvwait;

      struct capincci *nccis;

      struct mutex ncci_list_mtx;
};

/* -------- global variables ---------------------------------------- */

static DEFINE_RWLOCK(capidev_list_lock);
static LIST_HEAD(capidev_list);

#ifdef CONFIG_ISDN_CAPI_MIDDLEWARE
static DEFINE_RWLOCK(capiminor_list_lock);
static LIST_HEAD(capiminor_list);
#endif /* CONFIG_ISDN_CAPI_MIDDLEWARE */

#ifdef CONFIG_ISDN_CAPI_MIDDLEWARE
/* -------- datahandles --------------------------------------------- */

static int capincci_add_ack(struct capiminor *mp, u16 datahandle)
{
      struct datahandle_queue *n;
      unsigned long flags;

      n = kmalloc(sizeof(*n), GFP_ATOMIC);
      if (unlikely(!n)) {
            printk(KERN_ERR "capi: alloc datahandle failed\n");
            return -1;
      }
      n->datahandle = datahandle;
      INIT_LIST_HEAD(&n->list);
      spin_lock_irqsave(&mp->ackqlock, flags);
      list_add_tail(&n->list, &mp->ackqueue);
      mp->nack++;
      spin_unlock_irqrestore(&mp->ackqlock, flags);
      return 0;
}

static int capiminor_del_ack(struct capiminor *mp, u16 datahandle)
{
      struct datahandle_queue *p, *tmp;
      unsigned long flags;

      spin_lock_irqsave(&mp->ackqlock, flags);
      list_for_each_entry_safe(p, tmp, &mp->ackqueue, list) {
            if (p->datahandle == datahandle) {
                  list_del(&p->list);
                  kfree(p);
                  mp->nack--;
                  spin_unlock_irqrestore(&mp->ackqlock, flags);
                  return 0;
            }
      }
      spin_unlock_irqrestore(&mp->ackqlock, flags);
      return -1;
}

static void capiminor_del_all_ack(struct capiminor *mp)
{
      struct datahandle_queue *p, *tmp;
      unsigned long flags;

      spin_lock_irqsave(&mp->ackqlock, flags);
      list_for_each_entry_safe(p, tmp, &mp->ackqueue, list) {
            list_del(&p->list);
            kfree(p);
            mp->nack--;
      }
      spin_unlock_irqrestore(&mp->ackqlock, flags);
}


/* -------- struct capiminor ---------------------------------------- */

static struct capiminor *capiminor_alloc(struct capi20_appl *ap, u32 ncci)
{
      struct capiminor *mp, *p;
      unsigned int minor = 0;
      unsigned long flags;

      mp = kzalloc(sizeof(*mp), GFP_ATOMIC);
      if (!mp) {
            printk(KERN_ERR "capi: can't alloc capiminor\n");
            return NULL;
      }

      mp->ap = ap;
      mp->ncci = ncci;
      mp->msgid = 0;
      atomic_set(&mp->ttyopencount,0);
      INIT_LIST_HEAD(&mp->ackqueue);
      spin_lock_init(&mp->ackqlock);

      skb_queue_head_init(&mp->inqueue);
      skb_queue_head_init(&mp->outqueue);

      /* Allocate the least unused minor number.
       */
      write_lock_irqsave(&capiminor_list_lock, flags);
      if (list_empty(&capiminor_list))
            list_add(&mp->list, &capiminor_list);
      else {
            list_for_each_entry(p, &capiminor_list, list) {
                  if (p->minor > minor)
                        break;
                  minor++;
            }
            
            if (minor < capi_ttyminors) {
                  mp->minor = minor;
                  list_add(&mp->list, p->list.prev);
            }
      }
            write_unlock_irqrestore(&capiminor_list_lock, flags);

      if (!(minor < capi_ttyminors)) {
            printk(KERN_NOTICE "capi: out of minors\n");
                  kfree(mp);
            return NULL;
      }

      return mp;
}

static void capiminor_free(struct capiminor *mp)
{
      unsigned long flags;

      write_lock_irqsave(&capiminor_list_lock, flags);
      list_del(&mp->list);
      write_unlock_irqrestore(&capiminor_list_lock, flags);

      if (mp->ttyskb) kfree_skb(mp->ttyskb);
      mp->ttyskb = NULL;
      skb_queue_purge(&mp->inqueue);
      skb_queue_purge(&mp->outqueue);
      capiminor_del_all_ack(mp);
      kfree(mp);
}

static struct capiminor *capiminor_find(unsigned int minor)
{
      struct list_head *l;
      struct capiminor *p = NULL;

      read_lock(&capiminor_list_lock);
      list_for_each(l, &capiminor_list) {
            p = list_entry(l, struct capiminor, list);
            if (p->minor == minor)
                  break;
      }
      read_unlock(&capiminor_list_lock);
      if (l == &capiminor_list)
            return NULL;

      return p;
}
#endif /* CONFIG_ISDN_CAPI_MIDDLEWARE */

/* -------- struct capincci ----------------------------------------- */

static struct capincci *capincci_alloc(struct capidev *cdev, u32 ncci)
{
      struct capincci *np, **pp;
#ifdef CONFIG_ISDN_CAPI_MIDDLEWARE
      struct capiminor *mp = NULL;
#endif /* CONFIG_ISDN_CAPI_MIDDLEWARE */

      np = kzalloc(sizeof(*np), GFP_ATOMIC);
      if (!np)
            return NULL;
      np->ncci = ncci;
      np->cdev = cdev;
#ifdef CONFIG_ISDN_CAPI_MIDDLEWARE
      mp = NULL;
      if (cdev->userflags & CAPIFLAG_HIGHJACKING)
            mp = np->minorp = capiminor_alloc(&cdev->ap, ncci);
      if (mp) {
            mp->nccip = np;
#ifdef _DEBUG_REFCOUNT
            printk(KERN_DEBUG "set mp->nccip\n");
#endif
#if defined(CONFIG_ISDN_CAPI_CAPIFS) || defined(CONFIG_ISDN_CAPI_CAPIFS_MODULE)
            capifs_new_ncci(mp->minor, MKDEV(capi_ttymajor, mp->minor));
#endif
      }
#endif /* CONFIG_ISDN_CAPI_MIDDLEWARE */
      for (pp=&cdev->nccis; *pp; pp = &(*pp)->next)
            ;
      *pp = np;
        return np;
}

static void capincci_free(struct capidev *cdev, u32 ncci)
{
      struct capincci *np, **pp;
#ifdef CONFIG_ISDN_CAPI_MIDDLEWARE
      struct capiminor *mp;
#endif /* CONFIG_ISDN_CAPI_MIDDLEWARE */

      pp=&cdev->nccis;
      while (*pp) {
            np = *pp;
            if (ncci == 0xffffffff || np->ncci == ncci) {
                  *pp = (*pp)->next;
#ifdef CONFIG_ISDN_CAPI_MIDDLEWARE
                  if ((mp = np->minorp) != 0) {
#if defined(CONFIG_ISDN_CAPI_CAPIFS) || defined(CONFIG_ISDN_CAPI_CAPIFS_MODULE)
                        capifs_free_ncci(mp->minor);
#endif
                        if (mp->tty) {
                              mp->nccip = NULL;
#ifdef _DEBUG_REFCOUNT
                              printk(KERN_DEBUG "reset mp->nccip\n");
#endif
                              tty_hangup(mp->tty);
                        } else {
                              capiminor_free(mp);
                        }
                  }
#endif /* CONFIG_ISDN_CAPI_MIDDLEWARE */
                  kfree(np);
                  if (*pp == 0) return;
            } else {
                  pp = &(*pp)->next;
            }
      }
}

static struct capincci *capincci_find(struct capidev *cdev, u32 ncci)
{
      struct capincci *p;

      for (p=cdev->nccis; p ; p = p->next) {
            if (p->ncci == ncci)
                  break;
      }
      return p;
}

/* -------- struct capidev ------------------------------------------ */

static struct capidev *capidev_alloc(void)
{
      struct capidev *cdev;
      unsigned long flags;

      cdev = kzalloc(sizeof(*cdev), GFP_KERNEL);
      if (!cdev)
            return NULL;

      mutex_init(&cdev->ncci_list_mtx);
      skb_queue_head_init(&cdev->recvqueue);
      init_waitqueue_head(&cdev->recvwait);
      write_lock_irqsave(&capidev_list_lock, flags);
      list_add_tail(&cdev->list, &capidev_list);
      write_unlock_irqrestore(&capidev_list_lock, flags);
        return cdev;
}

static void capidev_free(struct capidev *cdev)
{
      unsigned long flags;

      if (cdev->ap.applid) {
            capi20_release(&cdev->ap);
            cdev->ap.applid = 0;
      }
      skb_queue_purge(&cdev->recvqueue);

      mutex_lock(&cdev->ncci_list_mtx);
      capincci_free(cdev, 0xffffffff);
      mutex_unlock(&cdev->ncci_list_mtx);

      write_lock_irqsave(&capidev_list_lock, flags);
      list_del(&cdev->list);
      write_unlock_irqrestore(&capidev_list_lock, flags);
      kfree(cdev);
}

#ifdef CONFIG_ISDN_CAPI_MIDDLEWARE
/* -------- handle data queue --------------------------------------- */

static struct sk_buff *
gen_data_b3_resp_for(struct capiminor *mp, struct sk_buff *skb)
{
      struct sk_buff *nskb;
      nskb = alloc_skb(CAPI_DATA_B3_RESP_LEN, GFP_ATOMIC);
      if (nskb) {
            u16 datahandle = CAPIMSG_U16(skb->data,CAPIMSG_BASELEN+4+4+2);
            unsigned char *s = skb_put(nskb, CAPI_DATA_B3_RESP_LEN);
            capimsg_setu16(s, 0, CAPI_DATA_B3_RESP_LEN);
            capimsg_setu16(s, 2, mp->ap->applid);
            capimsg_setu8 (s, 4, CAPI_DATA_B3);
            capimsg_setu8 (s, 5, CAPI_RESP);
            capimsg_setu16(s, 6, mp->msgid++);
            capimsg_setu32(s, 8, mp->ncci);
            capimsg_setu16(s, 12, datahandle);
      }
      return nskb;
}

static int handle_recv_skb(struct capiminor *mp, struct sk_buff *skb)
{
      struct sk_buff *nskb;
      int datalen;
      u16 errcode, datahandle;
      struct tty_ldisc *ld;
      
      datalen = skb->len - CAPIMSG_LEN(skb->data);
      if (mp->tty == NULL)
      {
#ifdef _DEBUG_DATAFLOW
            printk(KERN_DEBUG "capi: currently no receiver\n");
#endif
            return -1;
      }
      
      ld = tty_ldisc_ref(mp->tty);
      if (ld == NULL)
            return -1;
      if (ld->receive_buf == NULL) {
#if defined(_DEBUG_DATAFLOW) || defined(_DEBUG_TTYFUNCS)
            printk(KERN_DEBUG "capi: ldisc has no receive_buf function\n");
#endif
            goto bad;
      }
      if (mp->ttyinstop) {
#if defined(_DEBUG_DATAFLOW) || defined(_DEBUG_TTYFUNCS)
            printk(KERN_DEBUG "capi: recv tty throttled\n");
#endif
            goto bad;
      }
      if (mp->tty->receive_room < datalen) {
#if defined(_DEBUG_DATAFLOW) || defined(_DEBUG_TTYFUNCS)
            printk(KERN_DEBUG "capi: no room in tty\n");
#endif
            goto bad;
      }
      if ((nskb = gen_data_b3_resp_for(mp, skb)) == 0) {
            printk(KERN_ERR "capi: gen_data_b3_resp failed\n");
            goto bad;
      }
      datahandle = CAPIMSG_U16(skb->data,CAPIMSG_BASELEN+4);
      errcode = capi20_put_message(mp->ap, nskb);
      if (errcode != CAPI_NOERROR) {
            printk(KERN_ERR "capi: send DATA_B3_RESP failed=%x\n",
                        errcode);
            kfree_skb(nskb);
            goto bad;
      }
      (void)skb_pull(skb, CAPIMSG_LEN(skb->data));
#ifdef _DEBUG_DATAFLOW
      printk(KERN_DEBUG "capi: DATA_B3_RESP %u len=%d => ldisc\n",
                        datahandle, skb->len);
#endif
      ld->receive_buf(mp->tty, skb->data, NULL, skb->len);
      kfree_skb(skb);
      tty_ldisc_deref(ld);
      return 0;
bad:
      tty_ldisc_deref(ld);
      return -1;
}

static void handle_minor_recv(struct capiminor *mp)
{
      struct sk_buff *skb;
      while ((skb = skb_dequeue(&mp->inqueue)) != 0) {
            unsigned int len = skb->len;
            mp->inbytes -= len;
            if (handle_recv_skb(mp, skb) < 0) {
                  skb_queue_head(&mp->inqueue, skb);
                  mp->inbytes += len;
                  return;
            }
      }
}

static int handle_minor_send(struct capiminor *mp)
{
      struct sk_buff *skb;
      u16 len;
      int count = 0;
      u16 errcode;
      u16 datahandle;

      if (mp->tty && mp->ttyoutstop) {
#if defined(_DEBUG_DATAFLOW) || defined(_DEBUG_TTYFUNCS)
            printk(KERN_DEBUG "capi: send: tty stopped\n");
#endif
            return 0;
      }

      while ((skb = skb_dequeue(&mp->outqueue)) != 0) {
            datahandle = mp->datahandle;
            len = (u16)skb->len;
            skb_push(skb, CAPI_DATA_B3_REQ_LEN);
            memset(skb->data, 0, CAPI_DATA_B3_REQ_LEN);
            capimsg_setu16(skb->data, 0, CAPI_DATA_B3_REQ_LEN);
            capimsg_setu16(skb->data, 2, mp->ap->applid);
            capimsg_setu8 (skb->data, 4, CAPI_DATA_B3);
            capimsg_setu8 (skb->data, 5, CAPI_REQ);
            capimsg_setu16(skb->data, 6, mp->msgid++);
            capimsg_setu32(skb->data, 8, mp->ncci);   /* NCCI */
            capimsg_setu32(skb->data, 12, (u32)(long)skb->data);/* Data32 */
            capimsg_setu16(skb->data, 16, len); /* Data length */
            capimsg_setu16(skb->data, 18, datahandle);
            capimsg_setu16(skb->data, 20, 0);   /* Flags */

            if (capincci_add_ack(mp, datahandle) < 0) {
                  skb_pull(skb, CAPI_DATA_B3_REQ_LEN);
                  skb_queue_head(&mp->outqueue, skb);
                  return count;
            }
            errcode = capi20_put_message(mp->ap, skb);
            if (errcode == CAPI_NOERROR) {
                  mp->datahandle++;
                  count++;
                  mp->outbytes -= len;
#ifdef _DEBUG_DATAFLOW
                  printk(KERN_DEBUG "capi: DATA_B3_REQ %u len=%u\n",
                                          datahandle, len);
#endif
                  continue;
            }
            capiminor_del_ack(mp, datahandle);

            if (errcode == CAPI_SENDQUEUEFULL) {
                  skb_pull(skb, CAPI_DATA_B3_REQ_LEN);
                  skb_queue_head(&mp->outqueue, skb);
                  break;
            }

            /* ups, drop packet */
            printk(KERN_ERR "capi: put_message = %x\n", errcode);
            mp->outbytes -= len;
            kfree_skb(skb);
      }
      return count;
}

#endif /* CONFIG_ISDN_CAPI_MIDDLEWARE */
/* -------- function called by lower level -------------------------- */

static void capi_recv_message(struct capi20_appl *ap, struct sk_buff *skb)
{
      struct capidev *cdev = ap->private;
#ifdef CONFIG_ISDN_CAPI_MIDDLEWARE
      struct capiminor *mp;
      u16 datahandle;
#endif /* CONFIG_ISDN_CAPI_MIDDLEWARE */
      struct capincci *np;
      u32 ncci;
      unsigned long flags;

      if (CAPIMSG_CMD(skb->data) == CAPI_CONNECT_B3_CONF) {
            u16 info = CAPIMSG_U16(skb->data, 12); // Info field
            if (info == 0) {
                  mutex_lock(&cdev->ncci_list_mtx);
                  capincci_alloc(cdev, CAPIMSG_NCCI(skb->data));
                  mutex_unlock(&cdev->ncci_list_mtx);
            }
      }
      if (CAPIMSG_CMD(skb->data) == CAPI_CONNECT_B3_IND) {
            mutex_lock(&cdev->ncci_list_mtx);
            capincci_alloc(cdev, CAPIMSG_NCCI(skb->data));
            mutex_unlock(&cdev->ncci_list_mtx);
      }
      spin_lock_irqsave(&workaround_lock, flags);
      if (CAPIMSG_COMMAND(skb->data) != CAPI_DATA_B3) {
            skb_queue_tail(&cdev->recvqueue, skb);
            wake_up_interruptible(&cdev->recvwait);
            spin_unlock_irqrestore(&workaround_lock, flags);
            return;
      }
      ncci = CAPIMSG_CONTROL(skb->data);
      for (np = cdev->nccis; np && np->ncci != ncci; np = np->next)
            ;
      if (!np) {
            printk(KERN_ERR "BUG: capi_signal: ncci not found\n");
            skb_queue_tail(&cdev->recvqueue, skb);
            wake_up_interruptible(&cdev->recvwait);
            spin_unlock_irqrestore(&workaround_lock, flags);
            return;
      }
#ifndef CONFIG_ISDN_CAPI_MIDDLEWARE
      skb_queue_tail(&cdev->recvqueue, skb);
      wake_up_interruptible(&cdev->recvwait);
#else /* CONFIG_ISDN_CAPI_MIDDLEWARE */
      mp = np->minorp;
      if (!mp) {
            skb_queue_tail(&cdev->recvqueue, skb);
            wake_up_interruptible(&cdev->recvwait);
            spin_unlock_irqrestore(&workaround_lock, flags);
            return;
      }


      if (CAPIMSG_SUBCOMMAND(skb->data) == CAPI_IND) {
            
            datahandle = CAPIMSG_U16(skb->data, CAPIMSG_BASELEN+4+4+2);
#ifdef _DEBUG_DATAFLOW
            printk(KERN_DEBUG "capi_signal: DATA_B3_IND %u len=%d\n",
                        datahandle, skb->len-CAPIMSG_LEN(skb->data));
#endif
            skb_queue_tail(&mp->inqueue, skb);
            mp->inbytes += skb->len;
            handle_minor_recv(mp);

      } else if (CAPIMSG_SUBCOMMAND(skb->data) == CAPI_CONF) {

            datahandle = CAPIMSG_U16(skb->data, CAPIMSG_BASELEN+4);
#ifdef _DEBUG_DATAFLOW
            printk(KERN_DEBUG "capi_signal: DATA_B3_CONF %u 0x%x\n",
                        datahandle,
                        CAPIMSG_U16(skb->data, CAPIMSG_BASELEN+4+2));
#endif
            kfree_skb(skb);
            (void)capiminor_del_ack(mp, datahandle);
            if (mp->tty)
                  tty_wakeup(mp->tty);
            (void)handle_minor_send(mp);

      } else {
            /* ups, let capi application handle it :-) */
            skb_queue_tail(&cdev->recvqueue, skb);
            wake_up_interruptible(&cdev->recvwait);
      }
#endif /* CONFIG_ISDN_CAPI_MIDDLEWARE */
      spin_unlock_irqrestore(&workaround_lock, flags);
}

/* -------- file_operations for capidev ----------------------------- */

static ssize_t
capi_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
{
      struct capidev *cdev = (struct capidev *)file->private_data;
      struct sk_buff *skb;
      size_t copied;

      if (!cdev->ap.applid)
            return -ENODEV;

      if ((skb = skb_dequeue(&cdev->recvqueue)) == 0) {

            if (file->f_flags & O_NONBLOCK)
                  return -EAGAIN;

            for (;;) {
                  interruptible_sleep_on(&cdev->recvwait);
                  if ((skb = skb_dequeue(&cdev->recvqueue)) != 0)
                        break;
                  if (signal_pending(current))
                        break;
            }
            if (skb == 0)
                  return -ERESTARTNOHAND;
      }
      if (skb->len > count) {
            skb_queue_head(&cdev->recvqueue, skb);
            return -EMSGSIZE;
      }
      if (copy_to_user(buf, skb->data, skb->len)) {
            skb_queue_head(&cdev->recvqueue, skb);
            return -EFAULT;
      }
      copied = skb->len;

      kfree_skb(skb);

      return copied;
}

static ssize_t
capi_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
{
      struct capidev *cdev = (struct capidev *)file->private_data;
      struct sk_buff *skb;
      u16 mlen;

      if (!cdev->ap.applid)
            return -ENODEV;

      skb = alloc_skb(count, GFP_USER);
      if (!skb)
            return -ENOMEM;

      if (copy_from_user(skb_put(skb, count), buf, count)) {
            kfree_skb(skb);
            return -EFAULT;
      }
      mlen = CAPIMSG_LEN(skb->data);
      if (CAPIMSG_CMD(skb->data) == CAPI_DATA_B3_REQ) {
            if ((size_t)(mlen + CAPIMSG_DATALEN(skb->data)) != count) {
                  kfree_skb(skb);
                  return -EINVAL;
            }
      } else {
            if (mlen != count) {
                  kfree_skb(skb);
                  return -EINVAL;
            }
      }
      CAPIMSG_SETAPPID(skb->data, cdev->ap.applid);

      if (CAPIMSG_CMD(skb->data) == CAPI_DISCONNECT_B3_RESP) {
            mutex_lock(&cdev->ncci_list_mtx);
            capincci_free(cdev, CAPIMSG_NCCI(skb->data));
            mutex_unlock(&cdev->ncci_list_mtx);
      }

      cdev->errcode = capi20_put_message(&cdev->ap, skb);

      if (cdev->errcode) {
            kfree_skb(skb);
            return -EIO;
      }
      return count;
}

static unsigned int
capi_poll(struct file *file, poll_table * wait)
{
      struct capidev *cdev = (struct capidev *)file->private_data;
      unsigned int mask = 0;

      if (!cdev->ap.applid)
            return POLLERR;

      poll_wait(file, &(cdev->recvwait), wait);
      mask = POLLOUT | POLLWRNORM;
      if (!skb_queue_empty(&cdev->recvqueue))
            mask |= POLLIN | POLLRDNORM;
      return mask;
}

static int
capi_ioctl(struct inode *inode, struct file *file,
         unsigned int cmd, unsigned long arg)
{
      struct capidev *cdev = file->private_data;
      struct capi20_appl *ap = &cdev->ap;
      capi_ioctl_struct data;
      int retval = -EINVAL;
      void __user *argp = (void __user *)arg;

      switch (cmd) {
      case CAPI_REGISTER:
            {
                  if (ap->applid)
                        return -EEXIST;

                  if (copy_from_user(&cdev->ap.rparam, argp,
                                 sizeof(struct capi_register_params)))
                        return -EFAULT;
                  
                  cdev->ap.private = cdev;
                  cdev->ap.recv_message = capi_recv_message;
                  cdev->errcode = capi20_register(ap);
                  if (cdev->errcode) {
                        ap->applid = 0;
                        return -EIO;
                  }
            }
            return (int)ap->applid;

      case CAPI_GET_VERSION:
            {
                  if (copy_from_user(&data.contr, argp,
                                    sizeof(data.contr)))
                        return -EFAULT;
                    cdev->errcode = capi20_get_version(data.contr, &data.version);
                  if (cdev->errcode)
                        return -EIO;
                  if (copy_to_user(argp, &data.version,
                               sizeof(data.version)))
                        return -EFAULT;
            }
            return 0;

      case CAPI_GET_SERIAL:
            {
                  if (copy_from_user(&data.contr, argp,
                                 sizeof(data.contr)))
                        return -EFAULT;
                  cdev->errcode = capi20_get_serial (data.contr, data.serial);
                  if (cdev->errcode)
                        return -EIO;
                  if (copy_to_user(argp, data.serial,
                               sizeof(data.serial)))
                        return -EFAULT;
            }
            return 0;
      case CAPI_GET_PROFILE:
            {
                  if (copy_from_user(&data.contr, argp,
                                 sizeof(data.contr)))
                        return -EFAULT;

                  if (data.contr == 0) {
                        cdev->errcode = capi20_get_profile(data.contr, &data.profile);
                        if (cdev->errcode)
                              return -EIO;

                        retval = copy_to_user(argp,
                              &data.profile.ncontroller,
                               sizeof(data.profile.ncontroller));

                  } else {
                        cdev->errcode = capi20_get_profile(data.contr, &data.profile);
                        if (cdev->errcode)
                              return -EIO;

                        retval = copy_to_user(argp, &data.profile,
                                       sizeof(data.profile));
                  }
                  if (retval)
                        return -EFAULT;
            }
            return 0;

      case CAPI_GET_MANUFACTURER:
            {
                  if (copy_from_user(&data.contr, argp,
                                 sizeof(data.contr)))
                        return -EFAULT;
                  cdev->errcode = capi20_get_manufacturer(data.contr, data.manufacturer);
                  if (cdev->errcode)
                        return -EIO;

                  if (copy_to_user(argp, data.manufacturer,
                               sizeof(data.manufacturer)))
                        return -EFAULT;

            }
            return 0;
      case CAPI_GET_ERRCODE:
            data.errcode = cdev->errcode;
            cdev->errcode = CAPI_NOERROR;
            if (arg) {
                  if (copy_to_user(argp, &data.errcode,
                               sizeof(data.errcode)))
                        return -EFAULT;
            }
            return data.errcode;

      case CAPI_INSTALLED:
            if (capi20_isinstalled() == CAPI_NOERROR)
                  return 0;
            return -ENXIO;

      case CAPI_MANUFACTURER_CMD:
            {
                  struct capi_manufacturer_cmd mcmd;
                  if (!capable(CAP_SYS_ADMIN))
                        return -EPERM;
                  if (copy_from_user(&mcmd, argp, sizeof(mcmd)))
                        return -EFAULT;
                  return capi20_manufacturer(mcmd.cmd, mcmd.data);
            }
            return 0;

      case CAPI_SET_FLAGS:
      case CAPI_CLR_FLAGS:
            {
                  unsigned userflags;
                  if (copy_from_user(&userflags, argp,
                                 sizeof(userflags)))
                        return -EFAULT;
                  if (cmd == CAPI_SET_FLAGS)
                        cdev->userflags |= userflags;
                  else
                        cdev->userflags &= ~userflags;
            }
            return 0;

      case CAPI_GET_FLAGS:
            if (copy_to_user(argp, &cdev->userflags,
                         sizeof(cdev->userflags)))
                  return -EFAULT;
            return 0;

      case CAPI_NCCI_OPENCOUNT:
            {
                  struct capincci *nccip;
#ifdef CONFIG_ISDN_CAPI_MIDDLEWARE
                  struct capiminor *mp;
#endif /* CONFIG_ISDN_CAPI_MIDDLEWARE */
                  unsigned ncci;
                  int count = 0;
                  if (copy_from_user(&ncci, argp, sizeof(ncci)))
                        return -EFAULT;

                  mutex_lock(&cdev->ncci_list_mtx);
                  if ((nccip = capincci_find(cdev, (u32) ncci)) == 0) {
                        mutex_unlock(&cdev->ncci_list_mtx);
                        return 0;
                  }
#ifdef CONFIG_ISDN_CAPI_MIDDLEWARE
                  if ((mp = nccip->minorp) != 0) {
                        count += atomic_read(&mp->ttyopencount);
                  }
#endif /* CONFIG_ISDN_CAPI_MIDDLEWARE */
                  mutex_unlock(&cdev->ncci_list_mtx);
                  return count;
            }
            return 0;

#ifdef CONFIG_ISDN_CAPI_MIDDLEWARE
      case CAPI_NCCI_GETUNIT:
            {
                  struct capincci *nccip;
                  struct capiminor *mp;
                  unsigned ncci;
                  int unit = 0;
                  if (copy_from_user(&ncci, argp,
                                 sizeof(ncci)))
                        return -EFAULT;
                  mutex_lock(&cdev->ncci_list_mtx);
                  nccip = capincci_find(cdev, (u32) ncci);
                  if (!nccip || (mp = nccip->minorp) == 0) {
                        mutex_unlock(&cdev->ncci_list_mtx);
                        return -ESRCH;
                  }
                  unit = mp->minor;
                  mutex_unlock(&cdev->ncci_list_mtx);
                  return unit;
            }
            return 0;
#endif /* CONFIG_ISDN_CAPI_MIDDLEWARE */
      }
      return -EINVAL;
}

static int
capi_open(struct inode *inode, struct file *file)
{
      if (file->private_data)
            return -EEXIST;

      if ((file->private_data = capidev_alloc()) == 0)
            return -ENOMEM;

      return nonseekable_open(inode, file);
}

static int
capi_release(struct inode *inode, struct file *file)
{
      struct capidev *cdev = (struct capidev *)file->private_data;

      capidev_free(cdev);
      file->private_data = NULL;
      
      return 0;
}

static const struct file_operations capi_fops =
{
      .owner            = THIS_MODULE,
      .llseek           = no_llseek,
      .read       = capi_read,
      .write            = capi_write,
      .poll       = capi_poll,
      .ioctl            = capi_ioctl,
      .open       = capi_open,
      .release    = capi_release,
};

#ifdef CONFIG_ISDN_CAPI_MIDDLEWARE
/* -------- tty_operations for capincci ----------------------------- */

static int capinc_tty_open(struct tty_struct * tty, struct file * file)
{
      struct capiminor *mp;
      unsigned long flags;

      if ((mp = capiminor_find(iminor(file->f_path.dentry->d_inode))) == 0)
            return -ENXIO;
      if (mp->nccip == 0)
            return -ENXIO;

      tty->driver_data = (void *)mp;

      spin_lock_irqsave(&workaround_lock, flags);
      if (atomic_read(&mp->ttyopencount) == 0)
            mp->tty = tty;
      atomic_inc(&mp->ttyopencount);
#ifdef _DEBUG_REFCOUNT
      printk(KERN_DEBUG "capinc_tty_open ocount=%d\n", atomic_read(&mp->ttyopencount));
#endif
      handle_minor_recv(mp);
      spin_unlock_irqrestore(&workaround_lock, flags);
      return 0;
}

static void capinc_tty_close(struct tty_struct * tty, struct file * file)
{
      struct capiminor *mp;

      mp = (struct capiminor *)tty->driver_data;
      if (mp)     {
            if (atomic_dec_and_test(&mp->ttyopencount)) {
#ifdef _DEBUG_REFCOUNT
                  printk(KERN_DEBUG "capinc_tty_close lastclose\n");
#endif
                  tty->driver_data = NULL;
                  mp->tty = NULL;
            }
#ifdef _DEBUG_REFCOUNT
            printk(KERN_DEBUG "capinc_tty_close ocount=%d\n", atomic_read(&mp->ttyopencount));
#endif
            if (mp->nccip == 0)
                  capiminor_free(mp);
      }

#ifdef _DEBUG_REFCOUNT
      printk(KERN_DEBUG "capinc_tty_close\n");
#endif
}

static int capinc_tty_write(struct tty_struct * tty,
                      const unsigned char *buf, int count)
{
      struct capiminor *mp = (struct capiminor *)tty->driver_data;
      struct sk_buff *skb;
      unsigned long flags;

#ifdef _DEBUG_TTYFUNCS
      printk(KERN_DEBUG "capinc_tty_write(count=%d)\n", count);
#endif

      if (!mp || !mp->nccip) {
#ifdef _DEBUG_TTYFUNCS
            printk(KERN_DEBUG "capinc_tty_write: mp or mp->ncci NULL\n");
#endif
            return 0;
      }

      spin_lock_irqsave(&workaround_lock, flags);
      skb = mp->ttyskb;
      if (skb) {
            mp->ttyskb = NULL;
            skb_queue_tail(&mp->outqueue, skb);
            mp->outbytes += skb->len;
      }

      skb = alloc_skb(CAPI_DATA_B3_REQ_LEN+count, GFP_ATOMIC);
      if (!skb) {
            printk(KERN_ERR "capinc_tty_write: alloc_skb failed\n");
            spin_unlock_irqrestore(&workaround_lock, flags);
            return -ENOMEM;
      }

      skb_reserve(skb, CAPI_DATA_B3_REQ_LEN);
      memcpy(skb_put(skb, count), buf, count);

      skb_queue_tail(&mp->outqueue, skb);
      mp->outbytes += skb->len;
      (void)handle_minor_send(mp);
      (void)handle_minor_recv(mp);
      spin_unlock_irqrestore(&workaround_lock, flags);
      return count;
}

static void capinc_tty_put_char(struct tty_struct *tty, unsigned char ch)
{
      struct capiminor *mp = (struct capiminor *)tty->driver_data;
      struct sk_buff *skb;
      unsigned long flags;

#ifdef _DEBUG_TTYFUNCS
      printk(KERN_DEBUG "capinc_put_char(%u)\n", ch);
#endif

      if (!mp || !mp->nccip) {
#ifdef _DEBUG_TTYFUNCS
            printk(KERN_DEBUG "capinc_tty_put_char: mp or mp->ncci NULL\n");
#endif
            return;
      }

      spin_lock_irqsave(&workaround_lock, flags);
      skb = mp->ttyskb;
      if (skb) {
            if (skb_tailroom(skb) > 0) {
                  *(skb_put(skb, 1)) = ch;
                  spin_unlock_irqrestore(&workaround_lock, flags);
                  return;
            }
            mp->ttyskb = NULL;
            skb_queue_tail(&mp->outqueue, skb);
            mp->outbytes += skb->len;
            (void)handle_minor_send(mp);
      }
      skb = alloc_skb(CAPI_DATA_B3_REQ_LEN+CAPI_MAX_BLKSIZE, GFP_ATOMIC);
      if (skb) {
            skb_reserve(skb, CAPI_DATA_B3_REQ_LEN);
            *(skb_put(skb, 1)) = ch;
            mp->ttyskb = skb;
      } else {
            printk(KERN_ERR "capinc_put_char: char %u lost\n", ch);
      }
      spin_unlock_irqrestore(&workaround_lock, flags);
}

static void capinc_tty_flush_chars(struct tty_struct *tty)
{
      struct capiminor *mp = (struct capiminor *)tty->driver_data;
      struct sk_buff *skb;
      unsigned long flags;

#ifdef _DEBUG_TTYFUNCS
      printk(KERN_DEBUG "capinc_tty_flush_chars\n");
#endif

      if (!mp || !mp->nccip) {
#ifdef _DEBUG_TTYFUNCS
            printk(KERN_DEBUG "capinc_tty_flush_chars: mp or mp->ncci NULL\n");
#endif
            return;
      }

      spin_lock_irqsave(&workaround_lock, flags);
      skb = mp->ttyskb;
      if (skb) {
            mp->ttyskb = NULL;
            skb_queue_tail(&mp->outqueue, skb);
            mp->outbytes += skb->len;
            (void)handle_minor_send(mp);
      }
      (void)handle_minor_recv(mp);
      spin_unlock_irqrestore(&workaround_lock, flags);
}

static int capinc_tty_write_room(struct tty_struct *tty)
{
      struct capiminor *mp = (struct capiminor *)tty->driver_data;
      int room;
      if (!mp || !mp->nccip) {
#ifdef _DEBUG_TTYFUNCS
            printk(KERN_DEBUG "capinc_tty_write_room: mp or mp->ncci NULL\n");
#endif
            return 0;
      }
      room = CAPINC_MAX_SENDQUEUE-skb_queue_len(&mp->outqueue);
      room *= CAPI_MAX_BLKSIZE;
#ifdef _DEBUG_TTYFUNCS
      printk(KERN_DEBUG "capinc_tty_write_room = %d\n", room);
#endif
      return room;
}

static int capinc_tty_chars_in_buffer(struct tty_struct *tty)
{
      struct capiminor *mp = (struct capiminor *)tty->driver_data;
      if (!mp || !mp->nccip) {
#ifdef _DEBUG_TTYFUNCS
            printk(KERN_DEBUG "capinc_tty_chars_in_buffer: mp or mp->ncci NULL\n");
#endif
            return 0;
      }
#ifdef _DEBUG_TTYFUNCS
      printk(KERN_DEBUG "capinc_tty_chars_in_buffer = %d nack=%d sq=%d rq=%d\n",
                  mp->outbytes, mp->nack,
                  skb_queue_len(&mp->outqueue),
                  skb_queue_len(&mp->inqueue));
#endif
      return mp->outbytes;
}

static int capinc_tty_ioctl(struct tty_struct *tty, struct file * file,
                unsigned int cmd, unsigned long arg)
{
      int error = 0;
      switch (cmd) {
      default:
            error = n_tty_ioctl (tty, file, cmd, arg);
            break;
      }
      return error;
}

static void capinc_tty_set_termios(struct tty_struct *tty, struct ktermios * old)
{
#ifdef _DEBUG_TTYFUNCS
      printk(KERN_DEBUG "capinc_tty_set_termios\n");
#endif
}

static void capinc_tty_throttle(struct tty_struct * tty)
{
      struct capiminor *mp = (struct capiminor *)tty->driver_data;
#ifdef _DEBUG_TTYFUNCS
      printk(KERN_DEBUG "capinc_tty_throttle\n");
#endif
      if (mp)
            mp->ttyinstop = 1;
}

static void capinc_tty_unthrottle(struct tty_struct * tty)
{
      struct capiminor *mp = (struct capiminor *)tty->driver_data;
      unsigned long flags;
#ifdef _DEBUG_TTYFUNCS
      printk(KERN_DEBUG "capinc_tty_unthrottle\n");
#endif
      if (mp) {
            spin_lock_irqsave(&workaround_lock, flags);
            mp->ttyinstop = 0;
            handle_minor_recv(mp);
            spin_unlock_irqrestore(&workaround_lock, flags);
      }
}

static void capinc_tty_stop(struct tty_struct *tty)
{
      struct capiminor *mp = (struct capiminor *)tty->driver_data;
#ifdef _DEBUG_TTYFUNCS
      printk(KERN_DEBUG "capinc_tty_stop\n");
#endif
      if (mp) {
            mp->ttyoutstop = 1;
      }
}

static void capinc_tty_start(struct tty_struct *tty)
{
      struct capiminor *mp = (struct capiminor *)tty->driver_data;
      unsigned long flags;
#ifdef _DEBUG_TTYFUNCS
      printk(KERN_DEBUG "capinc_tty_start\n");
#endif
      if (mp) {
            spin_lock_irqsave(&workaround_lock, flags);
            mp->ttyoutstop = 0;
            (void)handle_minor_send(mp);
            spin_unlock_irqrestore(&workaround_lock, flags);
      }
}

static void capinc_tty_hangup(struct tty_struct *tty)
{
#ifdef _DEBUG_TTYFUNCS
      printk(KERN_DEBUG "capinc_tty_hangup\n");
#endif
}

static void capinc_tty_break_ctl(struct tty_struct *tty, int state)
{
#ifdef _DEBUG_TTYFUNCS
      printk(KERN_DEBUG "capinc_tty_break_ctl(%d)\n", state);
#endif
}

static void capinc_tty_flush_buffer(struct tty_struct *tty)
{
#ifdef _DEBUG_TTYFUNCS
      printk(KERN_DEBUG "capinc_tty_flush_buffer\n");
#endif
}

static void capinc_tty_set_ldisc(struct tty_struct *tty)
{
#ifdef _DEBUG_TTYFUNCS
      printk(KERN_DEBUG "capinc_tty_set_ldisc\n");
#endif
}

static void capinc_tty_send_xchar(struct tty_struct *tty, char ch)
{
#ifdef _DEBUG_TTYFUNCS
      printk(KERN_DEBUG "capinc_tty_send_xchar(%d)\n", ch);
#endif
}

static int capinc_tty_read_proc(char *page, char **start, off_t off,
                        int count, int *eof, void *data)
{
      return 0;
}

static struct tty_driver *capinc_tty_driver;

static const struct tty_operations capinc_ops = {
      .open = capinc_tty_open,
      .close = capinc_tty_close,
      .write = capinc_tty_write,
      .put_char = capinc_tty_put_char,
      .flush_chars = capinc_tty_flush_chars,
      .write_room = capinc_tty_write_room,
      .chars_in_buffer = capinc_tty_chars_in_buffer,
      .ioctl = capinc_tty_ioctl,
      .set_termios = capinc_tty_set_termios,
      .throttle = capinc_tty_throttle,
      .unthrottle = capinc_tty_unthrottle,
      .stop = capinc_tty_stop,
      .start = capinc_tty_start,
      .hangup = capinc_tty_hangup,
      .break_ctl = capinc_tty_break_ctl,
      .flush_buffer = capinc_tty_flush_buffer,
      .set_ldisc = capinc_tty_set_ldisc,
      .send_xchar = capinc_tty_send_xchar,
      .read_proc = capinc_tty_read_proc,
};

static int capinc_tty_init(void)
{
      struct tty_driver *drv;
      
      if (capi_ttyminors > CAPINC_MAX_PORTS)
            capi_ttyminors = CAPINC_MAX_PORTS;
      if (capi_ttyminors <= 0)
            capi_ttyminors = CAPINC_NR_PORTS;

      drv = alloc_tty_driver(capi_ttyminors);
      if (!drv)
            return -ENOMEM;

      drv->owner = THIS_MODULE;
      drv->driver_name = "capi_nc";
      drv->name = "capi";
      drv->major = capi_ttymajor;
      drv->minor_start = 0;
      drv->type = TTY_DRIVER_TYPE_SERIAL;
      drv->subtype = SERIAL_TYPE_NORMAL;
      drv->init_termios = tty_std_termios;
      drv->init_termios.c_iflag = ICRNL;
      drv->init_termios.c_oflag = OPOST | ONLCR;
      drv->init_termios.c_cflag = B9600 | CS8 | CREAD | HUPCL | CLOCAL;
      drv->init_termios.c_lflag = 0;
      drv->flags = TTY_DRIVER_REAL_RAW|TTY_DRIVER_RESET_TERMIOS;
      tty_set_operations(drv, &capinc_ops);
      if (tty_register_driver(drv)) {
            put_tty_driver(drv);
            printk(KERN_ERR "Couldn't register capi_nc driver\n");
            return -1;
      }
      capinc_tty_driver = drv;
      return 0;
}

static void capinc_tty_exit(void)
{
      struct tty_driver *drv = capinc_tty_driver;
      int retval;
      if ((retval = tty_unregister_driver(drv)))
            printk(KERN_ERR "capi: failed to unregister capi_nc driver (%d)\n", retval);
      put_tty_driver(drv);
}

#endif /* CONFIG_ISDN_CAPI_MIDDLEWARE */

/* -------- /proc functions ----------------------------------------- */

/*
 * /proc/capi/capi20:
 *  minor applid nrecvctlpkt nrecvdatapkt nsendctlpkt nsenddatapkt
 */
static int proc_capidev_read_proc(char *page, char **start, off_t off,
                                       int count, int *eof, void *data)
{
        struct capidev *cdev;
      struct list_head *l;
      int len = 0;

      read_lock(&capidev_list_lock);
      list_for_each(l, &capidev_list) {
            cdev = list_entry(l, struct capidev, list);
            len += sprintf(page+len, "0 %d %lu %lu %lu %lu\n",
                  cdev->ap.applid,
                  cdev->ap.nrecvctlpkt,
                  cdev->ap.nrecvdatapkt,
                  cdev->ap.nsentctlpkt,
                  cdev->ap.nsentdatapkt);
            if (len <= off) {
                  off -= len;
                  len = 0;
            } else {
                  if (len-off > count)
                        goto endloop;
            }
      }

endloop:
      read_unlock(&capidev_list_lock);
      if (len < count)
            *eof = 1;
      if (len > count) len = count;
      if (len < 0) len = 0;
      return len;
}

/*
 * /proc/capi/capi20ncci:
 *  applid ncci
 */
static int proc_capincci_read_proc(char *page, char **start, off_t off,
                                       int count, int *eof, void *data)
{
        struct capidev *cdev;
        struct capincci *np;
      struct list_head *l;
      int len = 0;

      read_lock(&capidev_list_lock);
      list_for_each(l, &capidev_list) {
            cdev = list_entry(l, struct capidev, list);
            for (np=cdev->nccis; np; np = np->next) {
                  len += sprintf(page+len, "%d 0x%x\n",
                               cdev->ap.applid,
                               np->ncci);
                  if (len <= off) {
                        off -= len;
                        len = 0;
                  } else {
                        if (len-off > count)
                              goto endloop;
                  }
            }
      }
endloop:
      read_unlock(&capidev_list_lock);
      *start = page+off;
      if (len < count)
            *eof = 1;
      if (len>count) len = count;
      if (len<0) len = 0;
      return len;
}

static struct procfsentries {
  char *name;
  mode_t mode;
  int (*read_proc)(char *page, char **start, off_t off,
                                       int count, int *eof, void *data);
  struct proc_dir_entry *procent;
} procfsentries[] = {
   /* { "capi",           S_IFDIR, 0 }, */
   { "capi/capi20",       0    , proc_capidev_read_proc },
   { "capi/capi20ncci",   0    , proc_capincci_read_proc },
};

static void __init proc_init(void)
{
    int nelem = ARRAY_SIZE(procfsentries);
    int i;

    for (i=0; i < nelem; i++) {
        struct procfsentries *p = procfsentries + i;
      p->procent = create_proc_entry(p->name, p->mode, NULL);
      if (p->procent) p->procent->read_proc = p->read_proc;
    }
}

static void __exit proc_exit(void)
{
    int nelem = ARRAY_SIZE(procfsentries);
    int i;

    for (i=nelem-1; i >= 0; i--) {
        struct procfsentries *p = procfsentries + i;
      if (p->procent) {
         remove_proc_entry(p->name, NULL);
         p->procent = NULL;
      }
    }
}

/* -------- init function and module interface ---------------------- */


static char rev[32];

static int __init capi_init(void)
{
      char *p;
      char *compileinfo;
      int major_ret;

      if ((p = strchr(revision, ':')) != 0 && p[1]) {
            strlcpy(rev, p + 2, sizeof(rev));
            if ((p = strchr(rev, '$')) != 0 && p > rev)
               *(p-1) = 0;
      } else
            strcpy(rev, "1.0");

      major_ret = register_chrdev(capi_major, "capi20", &capi_fops);
      if (major_ret < 0) {
            printk(KERN_ERR "capi20: unable to get major %d\n", capi_major);
            return major_ret;
      }
      capi_class = class_create(THIS_MODULE, "capi");
      if (IS_ERR(capi_class)) {
            unregister_chrdev(capi_major, "capi20");
            return PTR_ERR(capi_class);
      }

      class_device_create(capi_class, NULL, MKDEV(capi_major, 0), NULL, "capi");

#ifdef CONFIG_ISDN_CAPI_MIDDLEWARE
      if (capinc_tty_init() < 0) {
            class_device_destroy(capi_class, MKDEV(capi_major, 0));
            class_destroy(capi_class);
            unregister_chrdev(capi_major, "capi20");
            return -ENOMEM;
      }
#endif /* CONFIG_ISDN_CAPI_MIDDLEWARE */

      proc_init();

#ifdef CONFIG_ISDN_CAPI_MIDDLEWARE
#if defined(CONFIG_ISDN_CAPI_CAPIFS) || defined(CONFIG_ISDN_CAPI_CAPIFS_MODULE)
        compileinfo = " (middleware+capifs)";
#else
        compileinfo = " (no capifs)";
#endif
#else
        compileinfo = " (no middleware)";
#endif
      printk(KERN_NOTICE "capi20: Rev %s: started up with major %d%s\n",
                        rev, capi_major, compileinfo);

      return 0;
}

static void __exit capi_exit(void)
{
      proc_exit();

      class_device_destroy(capi_class, MKDEV(capi_major, 0));
      class_destroy(capi_class);
      unregister_chrdev(capi_major, "capi20");

#ifdef CONFIG_ISDN_CAPI_MIDDLEWARE
      capinc_tty_exit();
#endif
      printk(KERN_NOTICE "capi: Rev %s: unloaded\n", rev);
}

module_init(capi_init);
module_exit(capi_exit);

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