isdn_common.c

讲述linux的初始化过程

		if (((!usage) || ((dev->usage[i] & ISDN_USAGE_MASK) == usage)) &&
		    (dev->drvmap[i] == di) &&
		    (dev->chanmap[i] == ch)) {
			dev->usage[i] &= (ISDN_USAGE_NONE | ISDN_USAGE_EXCLUSIVE);
			strcpy(dev->num[i], "???");
			dev->ibytes[i] = 0;
			dev->obytes[i] = 0;
// 20.10.99 JIM, try to reinitialize v110 !
			dev->v110emu[i] = 0;
			atomic_set(&(dev->v110use[i]), 0);
			isdn_v110_close(dev->v110[i]);
			dev->v110[i] = NULL;
// 20.10.99 JIM, try to reinitialize v110 !
			isdn_info_update();
			isdn_free_queue(&dev->drv[di]->rpqueue[ch]);
		}
	restore_flags(flags);
}

/*
 * Cancel Exclusive-Flag for ISDN-channel
 */
void
isdn_unexclusive_channel(int di, int ch)
{
	int i;
	ulong flags;

	save_flags(flags);
	cli();
	for (i = 0; i < ISDN_MAX_CHANNELS; i++)
		if ((dev->drvmap[i] == di) &&
		    (dev->chanmap[i] == ch)) {
			dev->usage[i] &= ~ISDN_USAGE_EXCLUSIVE;
			isdn_info_update();
			restore_flags(flags);
			return;
		}
	restore_flags(flags);
}

/*
 *  writebuf replacement for SKB_ABLE drivers
 */
static int
isdn_writebuf_stub(int drvidx, int chan, const u_char * buf, int len,
		   int user)
{
	int ret;
	int hl = dev->drv[drvidx]->interface->hl_hdrlen;
	struct sk_buff *skb = alloc_skb(hl + len, GFP_ATOMIC);

	if (!skb)
		return 0;
	skb_reserve(skb, hl);
	if (user)
		copy_from_user(skb_put(skb, len), buf, len);
	else
		memcpy(skb_put(skb, len), buf, len);
	ret = dev->drv[drvidx]->interface->writebuf_skb(drvidx, chan, 1, skb);
	if (ret <= 0)
		dev_kfree_skb(skb);
	if (ret > 0)
		dev->obytes[isdn_dc2minor(drvidx, chan)] += ret;
	return ret;
}

/*
 * Return: length of data on success, -ERRcode on failure.
 */
int
isdn_writebuf_skb_stub(int drvidx, int chan, int ack, struct sk_buff *skb)
{
	int ret;
	struct sk_buff *nskb = NULL;
	int v110_ret = skb->len;
	int idx = isdn_dc2minor(drvidx, chan);

	if (dev->v110[idx]) {
		atomic_inc(&dev->v110use[idx]);
		nskb = isdn_v110_encode(dev->v110[idx], skb);
		atomic_dec(&dev->v110use[idx]);
		if (!nskb)
			return 0;
		v110_ret = *((int *)nskb->data);
		skb_pull(nskb, sizeof(int));
		if (!nskb->len) {
			dev_kfree_skb(nskb);
			return v110_ret;
		}
		/* V.110 must always be acknowledged */
		ack = 1;
		ret = dev->drv[drvidx]->interface->writebuf_skb(drvidx, chan, ack, nskb);
	} else {
		int hl = dev->drv[drvidx]->interface->hl_hdrlen;

		if( skb_headroom(skb) < hl ){
			/* 
			 * This should only occur when new HL driver with
			 * increased hl_hdrlen was loaded after netdevice
			 * was created and connected to the new driver.
			 *
			 * The V.110 branch (re-allocates on its own) does
			 * not need this
			 */
			struct sk_buff * skb_tmp;

			skb_tmp = skb_realloc_headroom(skb, hl);
			printk(KERN_DEBUG "isdn_writebuf_skb_stub: reallocating headroom%s\n", skb_tmp ? "" : " failed");
			if (!skb_tmp) return -ENOMEM; /* 0 better? */
			ret = dev->drv[drvidx]->interface->writebuf_skb(drvidx, chan, ack, skb_tmp);
			if( ret > 0 ){
				dev_kfree_skb(skb);
			} else {
				dev_kfree_skb(skb_tmp);
			}
		} else {
			ret = dev->drv[drvidx]->interface->writebuf_skb(drvidx, chan, ack, skb);
		}
	}
	if (ret > 0) {
		dev->obytes[idx] += ret;
		if (dev->v110[idx]) {
			atomic_inc(&dev->v110use[idx]);
			dev->v110[idx]->skbuser++;
			atomic_dec(&dev->v110use[idx]);
			/* For V.110 return unencoded data length */
			ret = v110_ret;
			/* if the complete frame was send we free the skb;
			   if not upper function will requeue the skb */ 
			if (ret == skb->len)
				dev_kfree_skb(skb);
		}
	} else
		if (dev->v110[idx])
			dev_kfree_skb(nskb);
	return ret;
}

int
register_isdn_module(isdn_module *m) {
	return 0;
}

int
unregister_isdn_module(isdn_module *m) {
	return 0;
}

int
isdn_add_channels(driver *d, int drvidx, int n, int adding)
{
	int j, k, m;
	ulong flags;

	init_waitqueue_head(&d->st_waitq);
	if (d->flags & DRV_FLAG_RUNNING)
		return -1;
       	if (n < 1) return 0;

	m = (adding) ? d->channels + n : n;

	if (dev->channels + n > ISDN_MAX_CHANNELS) {
		printk(KERN_WARNING "register_isdn: Max. %d channels supported\n",
		       ISDN_MAX_CHANNELS);
		return -1;
	}

	if ((adding) && (d->rcverr))
		kfree(d->rcverr);
	if (!(d->rcverr = (int *) kmalloc(sizeof(int) * m, GFP_KERNEL))) {
		printk(KERN_WARNING "register_isdn: Could not alloc rcverr\n");
		return -1;
	}
	memset((char *) d->rcverr, 0, sizeof(int) * m);

	if ((adding) && (d->rcvcount))
		kfree(d->rcvcount);
	if (!(d->rcvcount = (int *) kmalloc(sizeof(int) * m, GFP_KERNEL))) {
		printk(KERN_WARNING "register_isdn: Could not alloc rcvcount\n");
		if (!adding) kfree(d->rcverr);
		return -1;
	}
	memset((char *) d->rcvcount, 0, sizeof(int) * m);

	if ((adding) && (d->rpqueue)) {
		for (j = 0; j < d->channels; j++)
			isdn_free_queue(&d->rpqueue[j]);
		kfree(d->rpqueue);
	}
	if (!(d->rpqueue =
	      (struct sk_buff_head *) kmalloc(sizeof(struct sk_buff_head) * m, GFP_KERNEL))) {
		printk(KERN_WARNING "register_isdn: Could not alloc rpqueue\n");
		if (!adding) {
			kfree(d->rcvcount);
			kfree(d->rcverr);
		}
		return -1; 
	}
	for (j = 0; j < m; j++) {
		skb_queue_head_init(&d->rpqueue[j]);
	}

	if ((adding) && (d->rcv_waitq))
		kfree(d->rcv_waitq);
	d->rcv_waitq = (wait_queue_head_t *)
		kmalloc(sizeof(wait_queue_head_t) * 2 * m, GFP_KERNEL);
	if (!d->rcv_waitq) {
		printk(KERN_WARNING "register_isdn: Could not alloc rcv_waitq\n");
		if (!adding) {
			kfree(d->rpqueue);
			kfree(d->rcvcount);
			kfree(d->rcverr);
		}
		return -1;
	}
	d->snd_waitq = d->rcv_waitq + m;
	for (j = 0; j < m; j++) {
		init_waitqueue_head(&d->rcv_waitq[j]);
		init_waitqueue_head(&d->snd_waitq[j]);
	}

	dev->channels += n;
	save_flags(flags);
	cli();
	for (j = d->channels; j < m; j++)
		for (k = 0; k < ISDN_MAX_CHANNELS; k++)
			if (dev->chanmap[k] < 0) {
				dev->chanmap[k] = j;
				dev->drvmap[k] = drvidx;
				isdn_register_devfs(k);
				break;
			}
	restore_flags(flags);
	d->channels = m;
	return 0;
}

/*
 * Low-level-driver registration
 */

static void
set_global_features(void)
{
	int drvidx;

	dev->global_features = 0;
	for (drvidx = 0; drvidx < ISDN_MAX_DRIVERS; drvidx++) {
		if (!dev->drv[drvidx])
			continue;
		if (dev->drv[drvidx]->interface)
			dev->global_features |= dev->drv[drvidx]->interface->features;
	}
}

#ifdef CONFIG_ISDN_DIVERSION

static char *map_drvname(int di)
{
  if ((di < 0) || (di >= ISDN_MAX_DRIVERS)) 
    return(NULL);
  return(dev->drvid[di]); /* driver name */
} /* map_drvname */

static int map_namedrv(char *id)
{  int i;

   for (i = 0; i < ISDN_MAX_DRIVERS; i++)
    { if (!strcmp(dev->drvid[i],id)) 
        return(i);
    }
   return(-1);
} /* map_namedrv */

int DIVERT_REG_NAME(isdn_divert_if *i_div)
{
  if (i_div->if_magic != DIVERT_IF_MAGIC) 
    return(DIVERT_VER_ERR);
  switch (i_div->cmd)
    {
      case DIVERT_CMD_REL:
        if (divert_if != i_div) 
          return(DIVERT_REL_ERR);
        divert_if = NULL; /* free interface */
        MOD_DEC_USE_COUNT;
        return(DIVERT_NO_ERR);

      case DIVERT_CMD_REG:
        if (divert_if) 
          return(DIVERT_REG_ERR);
        i_div->ll_cmd = isdn_command; /* set command function */
        i_div->drv_to_name = map_drvname; 
        i_div->name_to_drv = map_namedrv; 
        MOD_INC_USE_COUNT;
        divert_if = i_div; /* remember interface */
        return(DIVERT_NO_ERR);

      default:
        return(DIVERT_CMD_ERR);   
    }
} /* DIVERT_REG_NAME */

EXPORT_SYMBOL(DIVERT_REG_NAME);

#endif CONFIG_ISDN_DIVERSION


EXPORT_SYMBOL(register_isdn);
EXPORT_SYMBOL(register_isdn_module);
EXPORT_SYMBOL(unregister_isdn_module);
#ifdef CONFIG_ISDN_PPP
EXPORT_SYMBOL(isdn_ppp_register_compressor);
EXPORT_SYMBOL(isdn_ppp_unregister_compressor);
#endif

int
register_isdn(isdn_if * i)
{
	driver *d;
	int j;
	ulong flags;
	int drvidx;

	if (dev->drivers >= ISDN_MAX_DRIVERS) {
		printk(KERN_WARNING "register_isdn: Max. %d drivers supported\n",
		       ISDN_MAX_DRIVERS);
		return 0;
	}
	if (!i->writebuf_skb) {
		printk(KERN_WARNING "register_isdn: No write routine given.\n");
		return 0;
	}
	if (!(d = (driver *) kmalloc(sizeof(driver), GFP_KERNEL))) {
		printk(KERN_WARNING "register_isdn: Could not alloc driver-struct\n");
		return 0;
	}
	memset((char *) d, 0, sizeof(driver));

	d->maxbufsize = i->maxbufsize;
	d->pktcount = 0;
	d->stavail = 0;
	d->flags = DRV_FLAG_LOADED;
	d->online = 0;
	d->interface = i;
	d->channels = 0;
	for (drvidx = 0; drvidx < ISDN_MAX_DRIVERS; drvidx++)
		if (!dev->drv[drvidx])
			break;
	if (isdn_add_channels(d, drvidx, i->channels, 0)) {
		kfree(d);
		return 0;
	}
	i->channels = drvidx;
	i->rcvcallb_skb = isdn_receive_skb_callback;
	i->statcallb = isdn_status_callback;
	if (!strlen(i->id))
		sprintf(i->id, "line%d", drvidx);
	save_flags(flags);
	cli();
	for (j = 0; j < drvidx; j++)
		if (!strcmp(i->id, dev->drvid[j]))
			sprintf(i->id, "line%d", drvidx);
	dev->drv[drvidx] = d;
	strcpy(dev->drvid[drvidx], i->id);
	isdn_info_update();
	dev->drivers++;
	set_global_features();
	restore_flags(flags);
	return 1;
}

/*
 *****************************************************************************
 * And now the modules code.
 *****************************************************************************
 */

extern int printk(const char *fmt,...);

#ifdef MODULE
#define isdn_init init_module
#endif

static char *
isdn_getrev(const char *revision)
{
	char *rev;
	char *p;

	if ((p = strchr(revision, ':'))) {
		rev = p + 2;
		p = strchr(rev, '$');
		*--p = 0;
	} else
		rev = "???";
	return rev;
}

#ifdef CONFIG_DEVFS_FS

static devfs_handle_t devfs_handle;

static void isdn_register_devfs(int k)
{
	char buf[11];

	sprintf (buf, "isdn%d", k);
	dev->devfs_handle_isdnX[k] =
	    devfs_register (devfs_handle, buf, DEVFS_FL_DEFAULT,
			    ISDN_MAJOR, ISDN_MINOR_B + k,0600 | S_IFCHR,
			    &isdn_fops, NULL);
	sprintf (buf, "isdnctrl%d", k);
	dev->devfs_handle_isdnctrlX[k] =
	    devfs_register (devfs_handle, buf, DEVFS_FL_DEFAULT,
			    ISDN_MAJOR, ISDN_MINOR_CTRL + k, 0600 | S_IFCHR,
			    &isdn_fops, NULL);
}

static void isdn_unregister_devfs(int k)
{
	devfs_unregister (dev->devfs_handle_isdnX[k]);
	devfs_unregister (dev->devfs_handle_isdnctrlX[k]);
}

static void isdn_init_devfs(void)
{
#  ifdef CONFIG_ISDN_PPP
	int i;
#  endif

	devfs_handle = devfs_mk_dir (NULL, "isdn", NULL);
#  ifdef CONFIG_ISDN_PPP
	for (i = 0; i < ISDN_MAX_CHANNELS; i++) {
		char buf[8];

		sprintf (buf, "ippp%d", i);
		dev->devfs_handle_ipppX[i] =
		    devfs_register (devfs_handle, buf, DEVFS_FL_DEFAULT,
				    ISDN_MAJOR, ISDN_MINOR_PPP + i,
				    0600 | S_IFCHR, &isdn_fops, NULL);
	}
#  endif

	dev->devfs_handle_isdninfo =
	    devfs_register (devfs_handle, "isdninfo", DEVFS_FL_DEFAULT,
			    ISDN_MAJOR, ISDN_MINOR_STATUS, 0600 | S_IFCHR,
			    &isdn_fops, NULL);
	dev->devfs_handle_isdnctrl =
	    devfs_register (devfs_handle, "isdnctrl", DEVFS_FL_DEFAULT,
			    ISDN_MAJOR, ISDN_MINOR_CTRL, 0600 | S_IFCHR, 
			    &isdn_fops, NULL);
}

static void isdn_cleanup_devfs(void)
{
#  ifdef CONFIG_ISDN_PPP
	int i;
	for (i = 0; i < ISDN_MAX_CHANNELS; i++) 
		devfs_unregister (dev->devfs_handle_ipppX[i]);
#  endif
	devfs_unregister (dev->devfs_handle_isdninfo);
	devfs_unregister (dev->devfs_handle_isdnctrl);
	devfs_unregister (devfs_handle);
}

#else   /* CONFIG_DEVFS_FS */
static void isdn_register_devfs(int dummy)
{
	return;
}

static void isdn_unregister_devfs(int dummy)
{
	return;
}

static void isdn_init_devfs(void)
{
    return;
}

static void isdn_cleanup_devfs(void)
{
    return;
}

#endif  /* CONFIG_DEVFS_FS */

/*
 * Allocate and initialize all data, register modem-devices
 */
int
isdn_init(void)
{
	int i;
	char tmprev[50];

	if (!(dev = (isdn_dev *) vmalloc(sizeof(isdn_dev)))) {
		printk(KERN_WARNING "isdn: Could not allocate device-struct.\n");
		return -EIO;
	}
	memset((char *) dev, 0, sizeof(isdn_dev));
	init_timer(&dev->timer);
	dev->timer.function = isdn_timer_funct;
	init_MUTEX(&dev->sem);
	init_waitqueue_head(&dev->info_waitq);
	for (i = 0; i < ISDN_MAX_CHANNELS; i++) {
		dev->drvmap[i] = -1;
		dev->chanmap[i] = -1;
		dev->m_idx[i] = -1;
		strcpy(dev->num[i], "???");
		init_waitqueue_head(&dev->mdm.info[i].open_wait);
		init_waitqueue_head(&dev->mdm.info[i].close_wait);
	}
	if (devfs_register_chrdev(ISDN_MAJOR, "isdn", &isdn_fops)) {
		printk(KERN_WARNING "isdn: Could not register control devices\n");
		vfree(dev);
		return -EIO;
	}
	isdn_init_devfs();
	if ((i = isdn_tty_modem_init()) < 0) {
		printk(KERN_WARNING "isdn: Could not register tty devices\n");
		if (i == -3)
			tty_unregister_driver(&dev->mdm.cua_modem);
		if (i <= -2)
			tty_unregister_driver(&dev->mdm.tty_modem);
		vfree(dev);
		isdn_cleanup_devfs();
		devfs_unregister_chrdev(ISDN_MAJOR, "isdn");
		return -EIO;
	}
#ifdef CONFIG_ISDN_PPP
	if (isdn_ppp_init() < 0) {
		printk(KERN_WARNING "isdn: Could not create PPP-device-structs\n");
		tty_unregister_driver(&dev->mdm.tty_modem);
		tty_unregister_driver(&dev->mdm.cua_modem);
		for (i = 0; i < ISDN_MAX_CHANNELS; i++)
			kfree(dev->mdm.info[i].xmit_buf - 4);
		isdn_cleanup_devfs();
		devfs_unregister_chrdev(ISDN_MAJOR, "isdn");
		vfree(dev);
		return -EIO;
	}
#endif                          /* CONFIG_ISDN_PPP */

	strcpy(tmprev, isdn_revision);
	printk(KERN_NOTICE "ISDN subsystem Rev: %s/", isdn_getrev(tmprev));
	strcpy(tmprev, isdn_tty_revision);
	printk("%s/", isdn_getrev(tmprev));
	strcpy(tmprev, isdn_net_revision);
	printk("%s/", isdn_getrev(tmprev));
	strcpy(tmprev, isdn_ppp_revision);
	printk("%s/", isdn_getrev(tmprev));
	strcpy(tmprev, isdn_audio_revision);
	printk("%s/", isdn_getrev(tmprev));
	strcpy(tmprev, isdn_v110_revision);
	printk("%s", isdn_getrev(tmprev));

#ifdef MODULE
	printk(" loaded\n");
#else
	printk("\n");
	isdn_cards_init();
#endif
	isdn_info_update();
	return 0;
}

#ifdef MODULE
/*
 * Unload module
 */
void
cleanup_module(void)
{
	int flags;
	int i;

#ifdef CONFIG_ISDN_PPP
	isdn_ppp_cleanup();
#endif
	save_flags(flags);
	cli();
	if (isdn_net_rmall() < 0) {
		printk(KERN_WARNING "isdn: net-device busy, remove cancelled\n");
		restore_flags(flags);
		return;
	}
	if (tty_unregister_driver(&dev->mdm.tty_modem)) {
		printk(KERN_WARNING "isdn: ttyI-device busy, remove cancelled\n");
		restore_flags(flags);
		return;
	}
	if (tty_unregister_driver(&dev->mdm.cua_modem)) {
		printk(KERN_WARNING "isdn: cui-device busy, remove cancelled\n");
		restore_flags(flags);
		return;
	}
	for (i = 0; i < ISDN_MAX_CHANNELS; i++) {
		isdn_tty_cleanup_xmit(&dev->mdm.info[i]);
		kfree(dev->mdm.info[i].xmit_buf - 4);
#ifdef CONFIG_ISDN_TTY_FAX
		kfree(dev->mdm.info[i].fax);
#endif
	}
	if (devfs_unregister_chrdev(ISDN_MAJOR, "isdn") != 0) {
		printk(KERN_WARNING "isdn: controldevice busy, remove cancelled\n");
		restore_flags(flags);
	} else {
		isdn_cleanup_devfs();
		del_timer(&dev->timer);
		restore_flags(flags);
		/* call vfree with interrupts enabled, else it will hang */
		vfree(dev);
		printk(KERN_NOTICE "ISDN-subsystem unloaded\n");
	}
}
#endif