drivers/net/usb/cdc-phonet.c - kernel/msm-4.19 - Gitiles

 /*
  * phonet.c -- USB CDC Phonet host driver
  *
  * Copyright (C) 2008-2009 Nokia Corporation. All rights reserved.
  *
  * Author: Rémi Denis-Courmont
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License
  * version 2 as published by the Free Software Foundation.
  *
  * 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., 51 Franklin St, Fifth Floor, Boston, MA
  * 02110-1301 USA
  */

 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/usb.h>
 #include <linux/usb/cdc.h>
 #include <linux/netdevice.h>
 #include <linux/if_arp.h>
 #include <linux/if_phonet.h>

 #define PN_MEDIA_USB	0x1B

 static const unsigned rxq_size = 17;

 struct usbpn_dev {
 	struct net_device	*dev;

 	struct usb_interface	*intf, *data_intf;
 	struct usb_device	*usb;
 	unsigned int		tx_pipe, rx_pipe;
 	u8 active_setting;
 	u8 disconnected;

 	unsigned		tx_queue;
 	spinlock_t		tx_lock;

 	spinlock_t		rx_lock;
 	struct sk_buff		*rx_skb;
 	struct urb		*urbs[0];
 };

 static void tx_complete(struct urb *req);
 static void rx_complete(struct urb *req);

 /*
  * Network device callbacks
  */
 static netdev_tx_t usbpn_xmit(struct sk_buff *skb, struct net_device *dev)
 {
 	struct usbpn_dev *pnd = netdev_priv(dev);
 	struct urb *req = NULL;
 	unsigned long flags;
 	int err;

 	if (skb->protocol != htons(ETH_P_PHONET))
 		goto drop;

 	req = usb_alloc_urb(0, GFP_ATOMIC);
 	if (!req)
 		goto drop;
 	usb_fill_bulk_urb(req, pnd->usb, pnd->tx_pipe, skb->data, skb->len,
 				tx_complete, skb);
 	req->transfer_flags = URB_ZERO_PACKET;
 	err = usb_submit_urb(req, GFP_ATOMIC);
 	if (err) {
 		usb_free_urb(req);
 		goto drop;
 	}

 	spin_lock_irqsave(&pnd->tx_lock, flags);
 	pnd->tx_queue++;
 	if (pnd->tx_queue >= dev->tx_queue_len)
 		netif_stop_queue(dev);
 	spin_unlock_irqrestore(&pnd->tx_lock, flags);
 	return NETDEV_TX_OK;

 drop:
 	dev_kfree_skb(skb);
 	dev->stats.tx_dropped++;
 	return NETDEV_TX_OK;
 }

 static void tx_complete(struct urb *req)
 {
 	struct sk_buff *skb = req->context;
 	struct net_device *dev = skb->dev;
 	struct usbpn_dev *pnd = netdev_priv(dev);

 	switch (req->status) {
 	case 0:
 		dev->stats.tx_bytes += skb->len;
 		break;

 	case -ENOENT:
 	case -ECONNRESET:
 	case -ESHUTDOWN:
 		dev->stats.tx_aborted_errors++;
 	default:
 		dev->stats.tx_errors++;
 		dev_dbg(&dev->dev, "TX error (%d)\n", req->status);
 	}
 	dev->stats.tx_packets++;

 	spin_lock(&pnd->tx_lock);
 	pnd->tx_queue--;
 	netif_wake_queue(dev);
 	spin_unlock(&pnd->tx_lock);

 	dev_kfree_skb_any(skb);
 	usb_free_urb(req);
 }

 static int rx_submit(struct usbpn_dev *pnd, struct urb *req, gfp_t gfp_flags)
 {
 	struct net_device *dev = pnd->dev;
 	struct page *page;
 	int err;

 	page = __netdev_alloc_page(dev, gfp_flags);
 	if (!page)
 		return -ENOMEM;

 	usb_fill_bulk_urb(req, pnd->usb, pnd->rx_pipe, page_address(page),
 				PAGE_SIZE, rx_complete, dev);
 	req->transfer_flags = 0;
 	err = usb_submit_urb(req, gfp_flags);
 	if (unlikely(err)) {
 		dev_dbg(&dev->dev, "RX submit error (%d)\n", err);
 		netdev_free_page(dev, page);
 	}
 	return err;
 }

 static void rx_complete(struct urb *req)
 {
 	struct net_device *dev = req->context;
 	struct usbpn_dev *pnd = netdev_priv(dev);
 	struct page *page = virt_to_page(req->transfer_buffer);
 	struct sk_buff *skb;
 	unsigned long flags;

 	switch (req->status) {
 	case 0:
 		spin_lock_irqsave(&pnd->rx_lock, flags);
 		skb = pnd->rx_skb;
 		if (!skb) {
 			skb = pnd->rx_skb = netdev_alloc_skb(dev, 12);
 			if (likely(skb)) {
 				/* Can't use pskb_pull() on page in IRQ */
 				memcpy(skb_put(skb, 1), page_address(page), 1);
 				skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags,
 						page, 1, req->actual_length);
 				page = NULL;
 			}
 		} else {
 			skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags,
 					page, 0, req->actual_length);
 			page = NULL;
 		}
 		if (req->actual_length < PAGE_SIZE)
 			pnd->rx_skb = NULL; /* Last fragment */
 		else
 			skb = NULL;
 		spin_unlock_irqrestore(&pnd->rx_lock, flags);
 		if (skb) {
 			skb->protocol = htons(ETH_P_PHONET);
 			skb_reset_mac_header(skb);
 			__skb_pull(skb, 1);
 			skb->dev = dev;
 			dev->stats.rx_packets++;
 			dev->stats.rx_bytes += skb->len;

 			netif_rx(skb);
 		}
 		goto resubmit;

 	case -ENOENT:
 	case -ECONNRESET:
 	case -ESHUTDOWN:
 		req = NULL;
 		break;

 	case -EOVERFLOW:
 		dev->stats.rx_over_errors++;
 		dev_dbg(&dev->dev, "RX overflow\n");
 		break;

 	case -EILSEQ:
 		dev->stats.rx_crc_errors++;
 		break;
 	}

 	dev->stats.rx_errors++;
 resubmit:
 	if (page)
 		netdev_free_page(dev, page);
 	if (req)
 		rx_submit(pnd, req, GFP_ATOMIC);
 }

 static int usbpn_close(struct net_device *dev);

 static int usbpn_open(struct net_device *dev)
 {
 	struct usbpn_dev *pnd = netdev_priv(dev);
 	int err;
 	unsigned i;
 	unsigned num = pnd->data_intf->cur_altsetting->desc.bInterfaceNumber;

 	err = usb_set_interface(pnd->usb, num, pnd->active_setting);
 	if (err)
 		return err;

 	for (i = 0; i < rxq_size; i++) {
 		struct urb *req = usb_alloc_urb(0, GFP_KERNEL);

 		if (!req || rx_submit(pnd, req, GFP_KERNEL)) {
 			usbpn_close(dev);
 			return -ENOMEM;
 		}
 		pnd->urbs[i] = req;
 	}

 	netif_wake_queue(dev);
 	return 0;
 }

 static int usbpn_close(struct net_device *dev)
 {
 	struct usbpn_dev *pnd = netdev_priv(dev);
 	unsigned i;
 	unsigned num = pnd->data_intf->cur_altsetting->desc.bInterfaceNumber;

 	netif_stop_queue(dev);

 	for (i = 0; i < rxq_size; i++) {
 		struct urb *req = pnd->urbs[i];

 		if (!req)
 			continue;
 		usb_kill_urb(req);
 		usb_free_urb(req);
 		pnd->urbs[i] = NULL;
 	}

 	return usb_set_interface(pnd->usb, num, !pnd->active_setting);
 }

 static int usbpn_set_mtu(struct net_device *dev, int new_mtu)
 {
 	if ((new_mtu < PHONET_MIN_MTU) || (new_mtu > PHONET_MAX_MTU))
 		return -EINVAL;

 	dev->mtu = new_mtu;
 	return 0;
 }

 static const struct net_device_ops usbpn_ops = {
 	.ndo_open	= usbpn_open,
 	.ndo_stop	= usbpn_close,
 	.ndo_start_xmit = usbpn_xmit,
 	.ndo_change_mtu = usbpn_set_mtu,
 };

 static void usbpn_setup(struct net_device *dev)
 {
 	dev->features		= 0;
 	dev->netdev_ops		= &usbpn_ops,
 	dev->header_ops		= &phonet_header_ops;
 	dev->type		= ARPHRD_PHONET;
 	dev->flags		= IFF_POINTOPOINT | IFF_NOARP;
 	dev->mtu		= PHONET_MAX_MTU;
 	dev->hard_header_len	= 1;
 	dev->dev_addr[0]	= PN_MEDIA_USB;
 	dev->addr_len		= 1;
 	dev->tx_queue_len	= 3;

 	dev->destructor		= free_netdev;
 }

 /*
  * USB driver callbacks
  */
 static struct usb_device_id usbpn_ids[] = {
 	{
 		.match_flags = USB_DEVICE_ID_MATCH_VENDOR
 			| USB_DEVICE_ID_MATCH_INT_CLASS
 			| USB_DEVICE_ID_MATCH_INT_SUBCLASS,
 		.idVendor = 0x0421, /* Nokia */
 		.bInterfaceClass = USB_CLASS_COMM,
 		.bInterfaceSubClass = 0xFE,
 	},
 	{ },
 };

 MODULE_DEVICE_TABLE(usb, usbpn_ids);

 static struct usb_driver usbpn_driver;

 int usbpn_probe(struct usb_interface *intf, const struct usb_device_id *id)
 {
 	static const char ifname[] = "usbpn%d";
 	const struct usb_cdc_union_desc *union_header = NULL;
 	const struct usb_cdc_header_desc *phonet_header = NULL;
 	const struct usb_host_interface *data_desc;
 	struct usb_interface *data_intf;
 	struct usb_device *usbdev = interface_to_usbdev(intf);
 	struct net_device *dev;
 	struct usbpn_dev *pnd;
 	u8 *data;
 	int len, err;

 	data = intf->altsetting->extra;
 	len = intf->altsetting->extralen;
 	while (len >= 3) {
 		u8 dlen = data[0];
 		if (dlen < 3)
 			return -EINVAL;

 		/* bDescriptorType */
 		if (data[1] == USB_DT_CS_INTERFACE) {
 			/* bDescriptorSubType */
 			switch (data[2]) {
 			case USB_CDC_UNION_TYPE:
 				if (union_header || dlen < 5)
 					break;
 				union_header =
 					(struct usb_cdc_union_desc *)data;
 				break;
 			case 0xAB:
 				if (phonet_header || dlen < 5)
 					break;
 				phonet_header =
 					(struct usb_cdc_header_desc *)data;
 				break;
 			}
 		}
 		data += dlen;
 		len -= dlen;
 	}

 	if (!union_header || !phonet_header)
 		return -EINVAL;

 	data_intf = usb_ifnum_to_if(usbdev, union_header->bSlaveInterface0);
 	if (data_intf == NULL)
 		return -ENODEV;
 	/* Data interface has one inactive and one active setting */
 	if (data_intf->num_altsetting != 2)
 		return -EINVAL;
 	if (data_intf->altsetting[0].desc.bNumEndpoints == 0
 	 && data_intf->altsetting[1].desc.bNumEndpoints == 2)
 		data_desc = data_intf->altsetting + 1;
 	else
 	if (data_intf->altsetting[0].desc.bNumEndpoints == 2
 	 && data_intf->altsetting[1].desc.bNumEndpoints == 0)
 		data_desc = data_intf->altsetting;
 	else
 		return -EINVAL;

 	dev = alloc_netdev(sizeof(*pnd) + sizeof(pnd->urbs[0]) * rxq_size,
 				ifname, usbpn_setup);
 	if (!dev)
 		return -ENOMEM;

 	pnd = netdev_priv(dev);
 	SET_NETDEV_DEV(dev, &intf->dev);
 	netif_stop_queue(dev);

 	pnd->dev = dev;
 	pnd->usb = usb_get_dev(usbdev);
 	pnd->intf = intf;
 	pnd->data_intf = data_intf;
 	spin_lock_init(&pnd->tx_lock);
 	spin_lock_init(&pnd->rx_lock);
 	/* Endpoints */
 	if (usb_pipein(data_desc->endpoint[0].desc.bEndpointAddress)) {
 		pnd->rx_pipe = usb_rcvbulkpipe(usbdev,
 			data_desc->endpoint[0].desc.bEndpointAddress);
 		pnd->tx_pipe = usb_sndbulkpipe(usbdev,
 			data_desc->endpoint[1].desc.bEndpointAddress);
 	} else {
 		pnd->rx_pipe = usb_rcvbulkpipe(usbdev,
 			data_desc->endpoint[1].desc.bEndpointAddress);
 		pnd->tx_pipe = usb_sndbulkpipe(usbdev,
 			data_desc->endpoint[0].desc.bEndpointAddress);
 	}
 	pnd->active_setting = data_desc - data_intf->altsetting;

 	err = usb_driver_claim_interface(&usbpn_driver, data_intf, pnd);
 	if (err)
 		goto out;

 	/* Force inactive mode until the network device is brought UP */
 	usb_set_interface(usbdev, union_header->bSlaveInterface0,
 				!pnd->active_setting);
 	usb_set_intfdata(intf, pnd);

 	err = register_netdev(dev);
 	if (err) {
 		usb_driver_release_interface(&usbpn_driver, data_intf);
 		goto out;
 	}

 	dev_dbg(&dev->dev, "USB CDC Phonet device found\n");
 	return 0;

 out:
 	usb_set_intfdata(intf, NULL);
 	free_netdev(dev);
 	return err;
 }

 static void usbpn_disconnect(struct usb_interface *intf)
 {
 	struct usbpn_dev *pnd = usb_get_intfdata(intf);
 	struct usb_device *usb = pnd->usb;

 	if (pnd->disconnected)
 		return;

 	pnd->disconnected = 1;
 	usb_driver_release_interface(&usbpn_driver,
 			(pnd->intf == intf) ? pnd->data_intf : pnd->intf);
 	unregister_netdev(pnd->dev);
 	usb_put_dev(usb);
 }

 static struct usb_driver usbpn_driver = {
 	.name =		"cdc_phonet",
 	.probe =	usbpn_probe,
 	.disconnect =	usbpn_disconnect,
 	.id_table =	usbpn_ids,
 };

 static int __init usbpn_init(void)
 {
 	return usb_register(&usbpn_driver);
 }

 static void __exit usbpn_exit(void)
 {
 	usb_deregister(&usbpn_driver);
 }

 module_init(usbpn_init);
 module_exit(usbpn_exit);

 MODULE_AUTHOR("Remi Denis-Courmont");
 MODULE_DESCRIPTION("USB CDC Phonet host interface");
 MODULE_LICENSE("GPL");
	/*
	* phonet.c -- USB CDC Phonet host driver
	*
	* Copyright (C) 2008-2009 Nokia Corporation. All rights reserved.
	*
	* Author: Rémi Denis-Courmont
	*
	* This program is free software; you can redistribute it and/or
	* modify it under the terms of the GNU General Public License
	* version 2 as published by the Free Software Foundation.
	*
	* 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., 51 Franklin St, Fifth Floor, Boston, MA
	* 02110-1301 USA
	*/

	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/usb.h>
	#include <linux/usb/cdc.h>
	#include <linux/netdevice.h>
	#include <linux/if_arp.h>
	#include <linux/if_phonet.h>

	#define PN_MEDIA_USB 0x1B

	static const unsigned rxq_size = 17;

	struct usbpn_dev {
	struct net_device *dev;

	struct usb_interface intf, data_intf;
	struct usb_device *usb;
	unsigned int tx_pipe, rx_pipe;
	u8 active_setting;
	u8 disconnected;

	unsigned tx_queue;
	spinlock_t tx_lock;

	spinlock_t rx_lock;
	struct sk_buff *rx_skb;
	struct urb *urbs[0];
	};

	static void tx_complete(struct urb *req);
	static void rx_complete(struct urb *req);

	/*
	* Network device callbacks
	*/
	static netdev_tx_t usbpn_xmit(struct sk_buff skb, struct net_device dev)
	{
	struct usbpn_dev *pnd = netdev_priv(dev);
	struct urb *req = NULL;
	unsigned long flags;
	int err;

	if (skb->protocol != htons(ETH_P_PHONET))
	goto drop;

	req = usb_alloc_urb(0, GFP_ATOMIC);
	if (!req)
	goto drop;
	usb_fill_bulk_urb(req, pnd->usb, pnd->tx_pipe, skb->data, skb->len,
	tx_complete, skb);
	req->transfer_flags = URB_ZERO_PACKET;
	err = usb_submit_urb(req, GFP_ATOMIC);
	if (err) {
	usb_free_urb(req);
	goto drop;
	}

	spin_lock_irqsave(&pnd->tx_lock, flags);
	pnd->tx_queue++;
	if (pnd->tx_queue >= dev->tx_queue_len)
	netif_stop_queue(dev);
	spin_unlock_irqrestore(&pnd->tx_lock, flags);
	return NETDEV_TX_OK;

	drop:
	dev_kfree_skb(skb);
	dev->stats.tx_dropped++;
	return NETDEV_TX_OK;
	}

	static void tx_complete(struct urb *req)
	{
	struct sk_buff *skb = req->context;
	struct net_device *dev = skb->dev;
	struct usbpn_dev *pnd = netdev_priv(dev);

	switch (req->status) {
	case 0:
	dev->stats.tx_bytes += skb->len;
	break;

	case -ENOENT:
	case -ECONNRESET:
	case -ESHUTDOWN:
	dev->stats.tx_aborted_errors++;
	default:
	dev->stats.tx_errors++;
	dev_dbg(&dev->dev, "TX error (%d)\n", req->status);
	}
	dev->stats.tx_packets++;

	spin_lock(&pnd->tx_lock);
	pnd->tx_queue--;
	netif_wake_queue(dev);
	spin_unlock(&pnd->tx_lock);

	dev_kfree_skb_any(skb);
	usb_free_urb(req);
	}

	static int rx_submit(struct usbpn_dev pnd, struct urb req, gfp_t gfp_flags)
	{
	struct net_device *dev = pnd->dev;
	struct page *page;
	int err;

	page = __netdev_alloc_page(dev, gfp_flags);
	if (!page)
	return -ENOMEM;

	usb_fill_bulk_urb(req, pnd->usb, pnd->rx_pipe, page_address(page),
	PAGE_SIZE, rx_complete, dev);
	req->transfer_flags = 0;
	err = usb_submit_urb(req, gfp_flags);
	if (unlikely(err)) {
	dev_dbg(&dev->dev, "RX submit error (%d)\n", err);
	netdev_free_page(dev, page);
	}
	return err;
	}

	static void rx_complete(struct urb *req)
	{
	struct net_device *dev = req->context;
	struct usbpn_dev *pnd = netdev_priv(dev);
	struct page *page = virt_to_page(req->transfer_buffer);
	struct sk_buff *skb;
	unsigned long flags;

	switch (req->status) {
	case 0:
	spin_lock_irqsave(&pnd->rx_lock, flags);
	skb = pnd->rx_skb;
	if (!skb) {
	skb = pnd->rx_skb = netdev_alloc_skb(dev, 12);
	if (likely(skb)) {
	/* Can't use pskb_pull() on page in IRQ */
	memcpy(skb_put(skb, 1), page_address(page), 1);
	skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags,
	page, 1, req->actual_length);
	page = NULL;
	}
	} else {
	skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags,
	page, 0, req->actual_length);
	page = NULL;
	}
	if (req->actual_length < PAGE_SIZE)
	pnd->rx_skb = NULL; /* Last fragment */
	else
	skb = NULL;
	spin_unlock_irqrestore(&pnd->rx_lock, flags);
	if (skb) {
	skb->protocol = htons(ETH_P_PHONET);
	skb_reset_mac_header(skb);
	__skb_pull(skb, 1);
	skb->dev = dev;
	dev->stats.rx_packets++;
	dev->stats.rx_bytes += skb->len;

	netif_rx(skb);
	}
	goto resubmit;

	case -ENOENT:
	case -ECONNRESET:
	case -ESHUTDOWN:
	req = NULL;
	break;

	case -EOVERFLOW:
	dev->stats.rx_over_errors++;
	dev_dbg(&dev->dev, "RX overflow\n");
	break;

	case -EILSEQ:
	dev->stats.rx_crc_errors++;
	break;
	}

	dev->stats.rx_errors++;
	resubmit:
	if (page)
	netdev_free_page(dev, page);
	if (req)
	rx_submit(pnd, req, GFP_ATOMIC);
	}

	static int usbpn_close(struct net_device *dev);

	static int usbpn_open(struct net_device *dev)
	{
	struct usbpn_dev *pnd = netdev_priv(dev);
	int err;
	unsigned i;
	unsigned num = pnd->data_intf->cur_altsetting->desc.bInterfaceNumber;

	err = usb_set_interface(pnd->usb, num, pnd->active_setting);
	if (err)
	return err;

	for (i = 0; i < rxq_size; i++) {
	struct urb *req = usb_alloc_urb(0, GFP_KERNEL);

	if (!req \|\| rx_submit(pnd, req, GFP_KERNEL)) {
	usbpn_close(dev);
	return -ENOMEM;
	}
	pnd->urbs[i] = req;
	}

	netif_wake_queue(dev);
	return 0;
	}

	static int usbpn_close(struct net_device *dev)
	{
	struct usbpn_dev *pnd = netdev_priv(dev);
	unsigned i;
	unsigned num = pnd->data_intf->cur_altsetting->desc.bInterfaceNumber;

	netif_stop_queue(dev);

	for (i = 0; i < rxq_size; i++) {
	struct urb *req = pnd->urbs[i];

	if (!req)
	continue;
	usb_kill_urb(req);
	usb_free_urb(req);
	pnd->urbs[i] = NULL;
	}

	return usb_set_interface(pnd->usb, num, !pnd->active_setting);
	}

	static int usbpn_set_mtu(struct net_device *dev, int new_mtu)
	{
	if ((new_mtu < PHONET_MIN_MTU) \|\| (new_mtu > PHONET_MAX_MTU))
	return -EINVAL;

	dev->mtu = new_mtu;
	return 0;
	}

	static const struct net_device_ops usbpn_ops = {
	.ndo_open = usbpn_open,
	.ndo_stop = usbpn_close,
	.ndo_start_xmit = usbpn_xmit,
	.ndo_change_mtu = usbpn_set_mtu,
	};

	static void usbpn_setup(struct net_device *dev)
	{
	dev->features = 0;
	dev->netdev_ops = &usbpn_ops,
	dev->header_ops = &phonet_header_ops;
	dev->type = ARPHRD_PHONET;
	dev->flags = IFF_POINTOPOINT \| IFF_NOARP;
	dev->mtu = PHONET_MAX_MTU;
	dev->hard_header_len = 1;
	dev->dev_addr[0] = PN_MEDIA_USB;
	dev->addr_len = 1;
	dev->tx_queue_len = 3;

	dev->destructor = free_netdev;
	}

	/*
	* USB driver callbacks
	*/
	static struct usb_device_id usbpn_ids[] = {
	{
	.match_flags = USB_DEVICE_ID_MATCH_VENDOR
	\| USB_DEVICE_ID_MATCH_INT_CLASS
	\| USB_DEVICE_ID_MATCH_INT_SUBCLASS,
	.idVendor = 0x0421, /* Nokia */
	.bInterfaceClass = USB_CLASS_COMM,
	.bInterfaceSubClass = 0xFE,
	},
	{ },
	};

	MODULE_DEVICE_TABLE(usb, usbpn_ids);

	static struct usb_driver usbpn_driver;

	int usbpn_probe(struct usb_interface intf, const struct usb_device_id id)
	{
	static const char ifname[] = "usbpn%d";
	const struct usb_cdc_union_desc *union_header = NULL;
	const struct usb_cdc_header_desc *phonet_header = NULL;
	const struct usb_host_interface *data_desc;
	struct usb_interface *data_intf;
	struct usb_device *usbdev = interface_to_usbdev(intf);
	struct net_device *dev;
	struct usbpn_dev *pnd;
	u8 *data;
	int len, err;

	data = intf->altsetting->extra;
	len = intf->altsetting->extralen;
	while (len >= 3) {
	u8 dlen = data[0];
	if (dlen < 3)
	return -EINVAL;

	/* bDescriptorType */
	if (data[1] == USB_DT_CS_INTERFACE) {
	/* bDescriptorSubType */
	switch (data[2]) {
	case USB_CDC_UNION_TYPE:
	if (union_header \|\| dlen < 5)
	break;
	union_header =
	(struct usb_cdc_union_desc *)data;
	break;
	case 0xAB:
	if (phonet_header \|\| dlen < 5)
	break;
	phonet_header =
	(struct usb_cdc_header_desc *)data;
	break;
	}
	}
	data += dlen;
	len -= dlen;
	}

	if (!union_header \|\| !phonet_header)
	return -EINVAL;

	data_intf = usb_ifnum_to_if(usbdev, union_header->bSlaveInterface0);
	if (data_intf == NULL)
	return -ENODEV;
	/* Data interface has one inactive and one active setting */
	if (data_intf->num_altsetting != 2)
	return -EINVAL;
	if (data_intf->altsetting[0].desc.bNumEndpoints == 0
	&& data_intf->altsetting[1].desc.bNumEndpoints == 2)
	data_desc = data_intf->altsetting + 1;
	else
	if (data_intf->altsetting[0].desc.bNumEndpoints == 2
	&& data_intf->altsetting[1].desc.bNumEndpoints == 0)
	data_desc = data_intf->altsetting;
	else
	return -EINVAL;

	dev = alloc_netdev(sizeof(pnd) + sizeof(pnd->urbs[0]) rxq_size,
	ifname, usbpn_setup);
	if (!dev)
	return -ENOMEM;

	pnd = netdev_priv(dev);
	SET_NETDEV_DEV(dev, &intf->dev);
	netif_stop_queue(dev);

	pnd->dev = dev;
	pnd->usb = usb_get_dev(usbdev);
	pnd->intf = intf;
	pnd->data_intf = data_intf;
	spin_lock_init(&pnd->tx_lock);
	spin_lock_init(&pnd->rx_lock);
	/* Endpoints */
	if (usb_pipein(data_desc->endpoint[0].desc.bEndpointAddress)) {
	pnd->rx_pipe = usb_rcvbulkpipe(usbdev,
	data_desc->endpoint[0].desc.bEndpointAddress);
	pnd->tx_pipe = usb_sndbulkpipe(usbdev,
	data_desc->endpoint[1].desc.bEndpointAddress);
	} else {
	pnd->rx_pipe = usb_rcvbulkpipe(usbdev,
	data_desc->endpoint[1].desc.bEndpointAddress);
	pnd->tx_pipe = usb_sndbulkpipe(usbdev,
	data_desc->endpoint[0].desc.bEndpointAddress);
	}
	pnd->active_setting = data_desc - data_intf->altsetting;

	err = usb_driver_claim_interface(&usbpn_driver, data_intf, pnd);
	if (err)
	goto out;

	/* Force inactive mode until the network device is brought UP */
	usb_set_interface(usbdev, union_header->bSlaveInterface0,
	!pnd->active_setting);
	usb_set_intfdata(intf, pnd);

	err = register_netdev(dev);
	if (err) {
	usb_driver_release_interface(&usbpn_driver, data_intf);
	goto out;
	}

	dev_dbg(&dev->dev, "USB CDC Phonet device found\n");
	return 0;

	out:
	usb_set_intfdata(intf, NULL);
	free_netdev(dev);
	return err;
	}

	static void usbpn_disconnect(struct usb_interface *intf)
	{
	struct usbpn_dev *pnd = usb_get_intfdata(intf);
	struct usb_device *usb = pnd->usb;

	if (pnd->disconnected)
	return;

	pnd->disconnected = 1;
	usb_driver_release_interface(&usbpn_driver,
	(pnd->intf == intf) ? pnd->data_intf : pnd->intf);
	unregister_netdev(pnd->dev);
	usb_put_dev(usb);
	}

	static struct usb_driver usbpn_driver = {
	.name = "cdc_phonet",
	.probe = usbpn_probe,
	.disconnect = usbpn_disconnect,
	.id_table = usbpn_ids,
	};

	static int __init usbpn_init(void)
	{
	return usb_register(&usbpn_driver);
	}

	static void __exit usbpn_exit(void)
	{
	usb_deregister(&usbpn_driver);
	}

	module_init(usbpn_init);
	module_exit(usbpn_exit);

	MODULE_AUTHOR("Remi Denis-Courmont");
	MODULE_DESCRIPTION("USB CDC Phonet host interface");
	MODULE_LICENSE("GPL");