drivers/net/usb/ipheth.c - third_party/linux - Git at Google

 /*
  * ipheth.c - Apple iPhone USB Ethernet driver
  *
  * Copyright (c) 2009 Diego Giagio <diego@giagio.com>
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
  * 3. Neither the name of GIAGIO.COM nor the names of its contributors
  *    may be used to endorse or promote products derived from this software
  *    without specific prior written permission.
  *
  * Alternatively, provided that this notice is retained in full, this
  * software may be distributed under the terms of the GNU General
  * Public License ("GPL") version 2, in which case the provisions of the
  * GPL apply INSTEAD OF those given above.
  *
  * The provided data structures and external interfaces from this code
  * are not restricted to be used by modules with a GPL compatible license.
  *
  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
  * DAMAGE.
  *
  *
  * Attention: iPhone device must be paired, otherwise it won't respond to our
  * driver. For more info: http://giagio.com/wiki/moin.cgi/iPhoneEthernetDriver
  *
  */

 #include <linux/kernel.h>
 #include <linux/errno.h>
 #include <linux/slab.h>
 #include <linux/module.h>
 #include <linux/netdevice.h>
 #include <linux/etherdevice.h>
 #include <linux/ethtool.h>
 #include <linux/usb.h>
 #include <linux/workqueue.h>

 #define USB_VENDOR_APPLE        0x05ac

 #define IPHETH_USBINTF_CLASS    255
 #define IPHETH_USBINTF_SUBCLASS 253
 #define IPHETH_USBINTF_PROTO    1

 #define IPHETH_BUF_SIZE         1514
 #define IPHETH_IP_ALIGN		2	/* padding at front of URB */
 #define IPHETH_TX_TIMEOUT       (5 * HZ)

 #define IPHETH_INTFNUM          2
 #define IPHETH_ALT_INTFNUM      1

 #define IPHETH_CTRL_ENDP        0x00
 #define IPHETH_CTRL_BUF_SIZE    0x40
 #define IPHETH_CTRL_TIMEOUT     (5 * HZ)

 #define IPHETH_CMD_GET_MACADDR   0x00
 #define IPHETH_CMD_CARRIER_CHECK 0x45

 #define IPHETH_CARRIER_CHECK_TIMEOUT round_jiffies_relative(1 * HZ)
 #define IPHETH_CARRIER_ON       0x04

 static const struct usb_device_id ipheth_table[] = {
 	{ USB_VENDOR_AND_INTERFACE_INFO(USB_VENDOR_APPLE, IPHETH_USBINTF_CLASS,
 					IPHETH_USBINTF_SUBCLASS,
 					IPHETH_USBINTF_PROTO) },
 	{ }
 };
 MODULE_DEVICE_TABLE(usb, ipheth_table);

 struct ipheth_device {
 	struct usb_device *udev;
 	struct usb_interface *intf;
 	struct net_device *net;
 	struct urb *tx_urb;
 	struct urb *rx_urb;
 	unsigned char *tx_buf;
 	unsigned char *rx_buf;
 	unsigned char *ctrl_buf;
 	u8 bulk_in;
 	u8 bulk_out;
 	struct delayed_work carrier_work;
 	bool confirmed_pairing;
 };

 static int ipheth_rx_submit(struct ipheth_device *dev, gfp_t mem_flags);

 static int ipheth_alloc_urbs(struct ipheth_device *iphone)
 {
 	struct urb *tx_urb = NULL;
 	struct urb *rx_urb = NULL;
 	u8 *tx_buf = NULL;
 	u8 *rx_buf = NULL;

 	tx_urb = usb_alloc_urb(0, GFP_KERNEL);
 	if (tx_urb == NULL)
 		goto error_nomem;

 	rx_urb = usb_alloc_urb(0, GFP_KERNEL);
 	if (rx_urb == NULL)
 		goto free_tx_urb;

 	tx_buf = usb_alloc_coherent(iphone->udev, IPHETH_BUF_SIZE,
 				    GFP_KERNEL, &tx_urb->transfer_dma);
 	if (tx_buf == NULL)
 		goto free_rx_urb;

 	rx_buf = usb_alloc_coherent(iphone->udev, IPHETH_BUF_SIZE + IPHETH_IP_ALIGN,
 				    GFP_KERNEL, &rx_urb->transfer_dma);
 	if (rx_buf == NULL)
 		goto free_tx_buf;


 	iphone->tx_urb = tx_urb;
 	iphone->rx_urb = rx_urb;
 	iphone->tx_buf = tx_buf;
 	iphone->rx_buf = rx_buf;
 	return 0;

 free_tx_buf:
 	usb_free_coherent(iphone->udev, IPHETH_BUF_SIZE, tx_buf,
 			  tx_urb->transfer_dma);
 free_rx_urb:
 	usb_free_urb(rx_urb);
 free_tx_urb:
 	usb_free_urb(tx_urb);
 error_nomem:
 	return -ENOMEM;
 }

 static void ipheth_free_urbs(struct ipheth_device *iphone)
 {
 	usb_free_coherent(iphone->udev, IPHETH_BUF_SIZE + IPHETH_IP_ALIGN, iphone->rx_buf,
 			  iphone->rx_urb->transfer_dma);
 	usb_free_coherent(iphone->udev, IPHETH_BUF_SIZE, iphone->tx_buf,
 			  iphone->tx_urb->transfer_dma);
 	usb_free_urb(iphone->rx_urb);
 	usb_free_urb(iphone->tx_urb);
 }

 static void ipheth_kill_urbs(struct ipheth_device *dev)
 {
 	usb_kill_urb(dev->tx_urb);
 	usb_kill_urb(dev->rx_urb);
 }

 static void ipheth_rcvbulk_callback(struct urb *urb)
 {
 	struct ipheth_device *dev;
 	struct sk_buff *skb;
 	int status;
 	char *buf;
 	int len;

 	dev = urb->context;
 	if (dev == NULL)
 		return;

 	status = urb->status;
 	switch (status) {
 	case -ENOENT:
 	case -ECONNRESET:
 	case -ESHUTDOWN:
 	case -EPROTO:
 		return;
 	case 0:
 		break;
 	default:
 		dev_err(&dev->intf->dev, "%s: urb status: %d\n",
 			__func__, status);
 		return;
 	}

 	if (urb->actual_length <= IPHETH_IP_ALIGN) {
 		dev->net->stats.rx_length_errors++;
 		return;
 	}
 	len = urb->actual_length - IPHETH_IP_ALIGN;
 	buf = urb->transfer_buffer + IPHETH_IP_ALIGN;

 	skb = dev_alloc_skb(len);
 	if (!skb) {
 		dev_err(&dev->intf->dev, "%s: dev_alloc_skb: -ENOMEM\n",
 			__func__);
 		dev->net->stats.rx_dropped++;
 		return;
 	}

 	skb_put_data(skb, buf, len);
 	skb->dev = dev->net;
 	skb->protocol = eth_type_trans(skb, dev->net);

 	dev->net->stats.rx_packets++;
 	dev->net->stats.rx_bytes += len;
 	dev->confirmed_pairing = true;
 	netif_rx(skb);
 	ipheth_rx_submit(dev, GFP_ATOMIC);
 }

 static void ipheth_sndbulk_callback(struct urb *urb)
 {
 	struct ipheth_device *dev;
 	int status = urb->status;

 	dev = urb->context;
 	if (dev == NULL)
 		return;

 	if (status != 0 &&
 	    status != -ENOENT &&
 	    status != -ECONNRESET &&
 	    status != -ESHUTDOWN)
 		dev_err(&dev->intf->dev, "%s: urb status: %d\n",
 		__func__, status);

 	if (status == 0)
 		netif_wake_queue(dev->net);
 	else
 		// on URB error, trigger immediate poll
 		schedule_delayed_work(&dev->carrier_work, 0);
 }

 static int ipheth_carrier_set(struct ipheth_device *dev)
 {
 	struct usb_device *udev;
 	int retval;

 	if (!dev->confirmed_pairing)
 		return 0;

 	udev = dev->udev;
 	retval = usb_control_msg(udev,
 			usb_rcvctrlpipe(udev, IPHETH_CTRL_ENDP),
 			IPHETH_CMD_CARRIER_CHECK, /* request */
 			0xc0, /* request type */
 			0x00, /* value */
 			0x02, /* index */
 			dev->ctrl_buf, IPHETH_CTRL_BUF_SIZE,
 			IPHETH_CTRL_TIMEOUT);
 	if (retval < 0) {
 		dev_err(&dev->intf->dev, "%s: usb_control_msg: %d\n",
 			__func__, retval);
 		return retval;
 	}

 	if (dev->ctrl_buf[0] == IPHETH_CARRIER_ON) {
 		netif_carrier_on(dev->net);
 		if (dev->tx_urb->status != -EINPROGRESS)
 			netif_wake_queue(dev->net);
 	} else {
 		netif_carrier_off(dev->net);
 		netif_stop_queue(dev->net);
 	}
 	return 0;
 }

 static void ipheth_carrier_check_work(struct work_struct *work)
 {
 	struct ipheth_device *dev = container_of(work, struct ipheth_device,
 						 carrier_work.work);

 	ipheth_carrier_set(dev);
 	schedule_delayed_work(&dev->carrier_work, IPHETH_CARRIER_CHECK_TIMEOUT);
 }

 static int ipheth_get_macaddr(struct ipheth_device *dev)
 {
 	struct usb_device *udev = dev->udev;
 	struct net_device *net = dev->net;
 	int retval;

 	retval = usb_control_msg(udev,
 				 usb_rcvctrlpipe(udev, IPHETH_CTRL_ENDP),
 				 IPHETH_CMD_GET_MACADDR, /* request */
 				 0xc0, /* request type */
 				 0x00, /* value */
 				 0x02, /* index */
 				 dev->ctrl_buf,
 				 IPHETH_CTRL_BUF_SIZE,
 				 IPHETH_CTRL_TIMEOUT);
 	if (retval < 0) {
 		dev_err(&dev->intf->dev, "%s: usb_control_msg: %d\n",
 			__func__, retval);
 	} else if (retval < ETH_ALEN) {
 		dev_err(&dev->intf->dev,
 			"%s: usb_control_msg: short packet: %d bytes\n",
 			__func__, retval);
 		retval = -EINVAL;
 	} else {
 		memcpy(net->dev_addr, dev->ctrl_buf, ETH_ALEN);
 		retval = 0;
 	}

 	return retval;
 }

 static int ipheth_rx_submit(struct ipheth_device *dev, gfp_t mem_flags)
 {
 	struct usb_device *udev = dev->udev;
 	int retval;

 	usb_fill_bulk_urb(dev->rx_urb, udev,
 			  usb_rcvbulkpipe(udev, dev->bulk_in),
 			  dev->rx_buf, IPHETH_BUF_SIZE + IPHETH_IP_ALIGN,
 			  ipheth_rcvbulk_callback,
 			  dev);
 	dev->rx_urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;

 	retval = usb_submit_urb(dev->rx_urb, mem_flags);
 	if (retval)
 		dev_err(&dev->intf->dev, "%s: usb_submit_urb: %d\n",
 			__func__, retval);
 	return retval;
 }

 static int ipheth_open(struct net_device *net)
 {
 	struct ipheth_device *dev = netdev_priv(net);
 	struct usb_device *udev = dev->udev;
 	int retval = 0;

 	usb_set_interface(udev, IPHETH_INTFNUM, IPHETH_ALT_INTFNUM);

 	retval = ipheth_carrier_set(dev);
 	if (retval)
 		return retval;

 	retval = ipheth_rx_submit(dev, GFP_KERNEL);
 	if (retval)
 		return retval;

 	schedule_delayed_work(&dev->carrier_work, IPHETH_CARRIER_CHECK_TIMEOUT);
 	return retval;
 }

 static int ipheth_close(struct net_device *net)
 {
 	struct ipheth_device *dev = netdev_priv(net);

 	cancel_delayed_work_sync(&dev->carrier_work);
 	netif_stop_queue(net);
 	return 0;
 }

 static netdev_tx_t ipheth_tx(struct sk_buff *skb, struct net_device *net)
 {
 	struct ipheth_device *dev = netdev_priv(net);
 	struct usb_device *udev = dev->udev;
 	int retval;

 	/* Paranoid */
 	if (skb->len > IPHETH_BUF_SIZE) {
 		WARN(1, "%s: skb too large: %d bytes\n", __func__, skb->len);
 		dev->net->stats.tx_dropped++;
 		dev_kfree_skb_any(skb);
 		return NETDEV_TX_OK;
 	}

 	memcpy(dev->tx_buf, skb->data, skb->len);
 	if (skb->len < IPHETH_BUF_SIZE)
 		memset(dev->tx_buf + skb->len, 0, IPHETH_BUF_SIZE - skb->len);

 	usb_fill_bulk_urb(dev->tx_urb, udev,
 			  usb_sndbulkpipe(udev, dev->bulk_out),
 			  dev->tx_buf, IPHETH_BUF_SIZE,
 			  ipheth_sndbulk_callback,
 			  dev);
 	dev->tx_urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;

 	netif_stop_queue(net);
 	retval = usb_submit_urb(dev->tx_urb, GFP_ATOMIC);
 	if (retval) {
 		dev_err(&dev->intf->dev, "%s: usb_submit_urb: %d\n",
 			__func__, retval);
 		dev->net->stats.tx_errors++;
 		dev_kfree_skb_any(skb);
 		netif_wake_queue(net);
 	} else {
 		dev->net->stats.tx_packets++;
 		dev->net->stats.tx_bytes += skb->len;
 		dev_consume_skb_any(skb);
 	}

 	return NETDEV_TX_OK;
 }

 static void ipheth_tx_timeout(struct net_device *net, unsigned int txqueue)
 {
 	struct ipheth_device *dev = netdev_priv(net);

 	dev_err(&dev->intf->dev, "%s: TX timeout\n", __func__);
 	dev->net->stats.tx_errors++;
 	usb_unlink_urb(dev->tx_urb);
 }

 static u32 ipheth_ethtool_op_get_link(struct net_device *net)
 {
 	struct ipheth_device *dev = netdev_priv(net);
 	return netif_carrier_ok(dev->net);
 }

 static const struct ethtool_ops ops = {
 	.get_link = ipheth_ethtool_op_get_link
 };

 static const struct net_device_ops ipheth_netdev_ops = {
 	.ndo_open = ipheth_open,
 	.ndo_stop = ipheth_close,
 	.ndo_start_xmit = ipheth_tx,
 	.ndo_tx_timeout = ipheth_tx_timeout,
 };

 static int ipheth_probe(struct usb_interface *intf,
 			const struct usb_device_id *id)
 {
 	struct usb_device *udev = interface_to_usbdev(intf);
 	struct usb_host_interface *hintf;
 	struct usb_endpoint_descriptor *endp;
 	struct ipheth_device *dev;
 	struct net_device *netdev;
 	int i;
 	int retval;

 	netdev = alloc_etherdev(sizeof(struct ipheth_device));
 	if (!netdev)
 		return -ENOMEM;

 	netdev->netdev_ops = &ipheth_netdev_ops;
 	netdev->watchdog_timeo = IPHETH_TX_TIMEOUT;
 	strcpy(netdev->name, "eth%d");

 	dev = netdev_priv(netdev);
 	dev->udev = udev;
 	dev->net = netdev;
 	dev->intf = intf;
 	dev->confirmed_pairing = false;
 	/* Set up endpoints */
 	hintf = usb_altnum_to_altsetting(intf, IPHETH_ALT_INTFNUM);
 	if (hintf == NULL) {
 		retval = -ENODEV;
 		dev_err(&intf->dev, "Unable to find alternate settings interface\n");
 		goto err_endpoints;
 	}

 	for (i = 0; i < hintf->desc.bNumEndpoints; i++) {
 		endp = &hintf->endpoint[i].desc;
 		if (usb_endpoint_is_bulk_in(endp))
 			dev->bulk_in = endp->bEndpointAddress;
 		else if (usb_endpoint_is_bulk_out(endp))
 			dev->bulk_out = endp->bEndpointAddress;
 	}
 	if (!(dev->bulk_in && dev->bulk_out)) {
 		retval = -ENODEV;
 		dev_err(&intf->dev, "Unable to find endpoints\n");
 		goto err_endpoints;
 	}

 	dev->ctrl_buf = kmalloc(IPHETH_CTRL_BUF_SIZE, GFP_KERNEL);
 	if (dev->ctrl_buf == NULL) {
 		retval = -ENOMEM;
 		goto err_alloc_ctrl_buf;
 	}

 	retval = ipheth_get_macaddr(dev);
 	if (retval)
 		goto err_get_macaddr;

 	INIT_DELAYED_WORK(&dev->carrier_work, ipheth_carrier_check_work);

 	retval = ipheth_alloc_urbs(dev);
 	if (retval) {
 		dev_err(&intf->dev, "error allocating urbs: %d\n", retval);
 		goto err_alloc_urbs;
 	}

 	usb_set_intfdata(intf, dev);

 	SET_NETDEV_DEV(netdev, &intf->dev);
 	netdev->ethtool_ops = &ops;

 	retval = register_netdev(netdev);
 	if (retval) {
 		dev_err(&intf->dev, "error registering netdev: %d\n", retval);
 		retval = -EIO;
 		goto err_register_netdev;
 	}
 	// carrier down and transmit queues stopped until packet from device
 	netif_carrier_off(netdev);
 	netif_tx_stop_all_queues(netdev);
 	dev_info(&intf->dev, "Apple iPhone USB Ethernet device attached\n");
 	return 0;

 err_register_netdev:
 	ipheth_free_urbs(dev);
 err_alloc_urbs:
 err_get_macaddr:
 err_alloc_ctrl_buf:
 	kfree(dev->ctrl_buf);
 err_endpoints:
 	free_netdev(netdev);
 	return retval;
 }

 static void ipheth_disconnect(struct usb_interface *intf)
 {
 	struct ipheth_device *dev;

 	dev = usb_get_intfdata(intf);
 	if (dev != NULL) {
 		unregister_netdev(dev->net);
 		ipheth_kill_urbs(dev);
 		ipheth_free_urbs(dev);
 		kfree(dev->ctrl_buf);
 		free_netdev(dev->net);
 	}
 	usb_set_intfdata(intf, NULL);
 	dev_info(&intf->dev, "Apple iPhone USB Ethernet now disconnected\n");
 }

 static struct usb_driver ipheth_driver = {
 	.name =		"ipheth",
 	.probe =	ipheth_probe,
 	.disconnect =	ipheth_disconnect,
 	.id_table =	ipheth_table,
 	.disable_hub_initiated_lpm = 1,
 };

 module_usb_driver(ipheth_driver);

 MODULE_AUTHOR("Diego Giagio <diego@giagio.com>");
 MODULE_DESCRIPTION("Apple iPhone USB Ethernet driver");
 MODULE_LICENSE("Dual BSD/GPL");
	/*
	* ipheth.c - Apple iPhone USB Ethernet driver
	*
	* Copyright (c) 2009 Diego Giagio <diego@giagio.com>
	* All rights reserved.
	*
	* Redistribution and use in source and binary forms, with or without
	* modification, are permitted provided that the following conditions
	* are met:
	* 1. Redistributions of source code must retain the above copyright
	* notice, this list of conditions and the following disclaimer.
	* 2. Redistributions in binary form must reproduce the above copyright
	* notice, this list of conditions and the following disclaimer in the
	* documentation and/or other materials provided with the distribution.
	* 3. Neither the name of GIAGIO.COM nor the names of its contributors
	* may be used to endorse or promote products derived from this software
	* without specific prior written permission.
	*
	* Alternatively, provided that this notice is retained in full, this
	* software may be distributed under the terms of the GNU General
	* Public License ("GPL") version 2, in which case the provisions of the
	* GPL apply INSTEAD OF those given above.
	*
	* The provided data structures and external interfaces from this code
	* are not restricted to be used by modules with a GPL compatible license.
	*
	* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
	* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
	* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
	* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
	* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
	* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
	* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
	* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
	* DAMAGE.
	*
	*
	* Attention: iPhone device must be paired, otherwise it won't respond to our
	* driver. For more info: http://giagio.com/wiki/moin.cgi/iPhoneEthernetDriver
	*
	*/

	#include <linux/kernel.h>
	#include <linux/errno.h>
	#include <linux/slab.h>
	#include <linux/module.h>
	#include <linux/netdevice.h>
	#include <linux/etherdevice.h>
	#include <linux/ethtool.h>
	#include <linux/usb.h>
	#include <linux/workqueue.h>

	#define USB_VENDOR_APPLE 0x05ac

	#define IPHETH_USBINTF_CLASS 255
	#define IPHETH_USBINTF_SUBCLASS 253
	#define IPHETH_USBINTF_PROTO 1

	#define IPHETH_BUF_SIZE 1514
	#define IPHETH_IP_ALIGN 2 /* padding at front of URB */
	#define IPHETH_TX_TIMEOUT (5 * HZ)

	#define IPHETH_INTFNUM 2
	#define IPHETH_ALT_INTFNUM 1

	#define IPHETH_CTRL_ENDP 0x00
	#define IPHETH_CTRL_BUF_SIZE 0x40
	#define IPHETH_CTRL_TIMEOUT (5 * HZ)

	#define IPHETH_CMD_GET_MACADDR 0x00
	#define IPHETH_CMD_CARRIER_CHECK 0x45

	#define IPHETH_CARRIER_CHECK_TIMEOUT round_jiffies_relative(1 * HZ)
	#define IPHETH_CARRIER_ON 0x04

	static const struct usb_device_id ipheth_table[] = {
	{ USB_VENDOR_AND_INTERFACE_INFO(USB_VENDOR_APPLE, IPHETH_USBINTF_CLASS,
	IPHETH_USBINTF_SUBCLASS,
	IPHETH_USBINTF_PROTO) },
	{ }
	};
	MODULE_DEVICE_TABLE(usb, ipheth_table);

	struct ipheth_device {
	struct usb_device *udev;
	struct usb_interface *intf;
	struct net_device *net;
	struct urb *tx_urb;
	struct urb *rx_urb;
	unsigned char *tx_buf;
	unsigned char *rx_buf;
	unsigned char *ctrl_buf;
	u8 bulk_in;
	u8 bulk_out;
	struct delayed_work carrier_work;
	bool confirmed_pairing;
	};

	static int ipheth_rx_submit(struct ipheth_device *dev, gfp_t mem_flags);

	static int ipheth_alloc_urbs(struct ipheth_device *iphone)
	{
	struct urb *tx_urb = NULL;
	struct urb *rx_urb = NULL;
	u8 *tx_buf = NULL;
	u8 *rx_buf = NULL;

	tx_urb = usb_alloc_urb(0, GFP_KERNEL);
	if (tx_urb == NULL)
	goto error_nomem;

	rx_urb = usb_alloc_urb(0, GFP_KERNEL);
	if (rx_urb == NULL)
	goto free_tx_urb;

	tx_buf = usb_alloc_coherent(iphone->udev, IPHETH_BUF_SIZE,
	GFP_KERNEL, &tx_urb->transfer_dma);
	if (tx_buf == NULL)
	goto free_rx_urb;

	rx_buf = usb_alloc_coherent(iphone->udev, IPHETH_BUF_SIZE + IPHETH_IP_ALIGN,
	GFP_KERNEL, &rx_urb->transfer_dma);
	if (rx_buf == NULL)
	goto free_tx_buf;


	iphone->tx_urb = tx_urb;
	iphone->rx_urb = rx_urb;
	iphone->tx_buf = tx_buf;
	iphone->rx_buf = rx_buf;
	return 0;

	free_tx_buf:
	usb_free_coherent(iphone->udev, IPHETH_BUF_SIZE, tx_buf,
	tx_urb->transfer_dma);
	free_rx_urb:
	usb_free_urb(rx_urb);
	free_tx_urb:
	usb_free_urb(tx_urb);
	error_nomem:
	return -ENOMEM;
	}

	static void ipheth_free_urbs(struct ipheth_device *iphone)
	{
	usb_free_coherent(iphone->udev, IPHETH_BUF_SIZE + IPHETH_IP_ALIGN, iphone->rx_buf,
	iphone->rx_urb->transfer_dma);
	usb_free_coherent(iphone->udev, IPHETH_BUF_SIZE, iphone->tx_buf,
	iphone->tx_urb->transfer_dma);
	usb_free_urb(iphone->rx_urb);
	usb_free_urb(iphone->tx_urb);
	}

	static void ipheth_kill_urbs(struct ipheth_device *dev)
	{
	usb_kill_urb(dev->tx_urb);
	usb_kill_urb(dev->rx_urb);
	}

	static void ipheth_rcvbulk_callback(struct urb *urb)
	{
	struct ipheth_device *dev;
	struct sk_buff *skb;
	int status;
	char *buf;
	int len;

	dev = urb->context;
	if (dev == NULL)
	return;

	status = urb->status;
	switch (status) {
	case -ENOENT:
	case -ECONNRESET:
	case -ESHUTDOWN:
	case -EPROTO:
	return;
	case 0:
	break;
	default:
	dev_err(&dev->intf->dev, "%s: urb status: %d\n",
	__func__, status);
	return;
	}

	if (urb->actual_length <= IPHETH_IP_ALIGN) {
	dev->net->stats.rx_length_errors++;
	return;
	}
	len = urb->actual_length - IPHETH_IP_ALIGN;
	buf = urb->transfer_buffer + IPHETH_IP_ALIGN;

	skb = dev_alloc_skb(len);
	if (!skb) {
	dev_err(&dev->intf->dev, "%s: dev_alloc_skb: -ENOMEM\n",
	__func__);
	dev->net->stats.rx_dropped++;
	return;
	}

	skb_put_data(skb, buf, len);
	skb->dev = dev->net;
	skb->protocol = eth_type_trans(skb, dev->net);

	dev->net->stats.rx_packets++;
	dev->net->stats.rx_bytes += len;
	dev->confirmed_pairing = true;
	netif_rx(skb);
	ipheth_rx_submit(dev, GFP_ATOMIC);
	}

	static void ipheth_sndbulk_callback(struct urb *urb)
	{
	struct ipheth_device *dev;
	int status = urb->status;

	dev = urb->context;
	if (dev == NULL)
	return;

	if (status != 0 &&
	status != -ENOENT &&
	status != -ECONNRESET &&
	status != -ESHUTDOWN)
	dev_err(&dev->intf->dev, "%s: urb status: %d\n",
	__func__, status);

	if (status == 0)
	netif_wake_queue(dev->net);
	else
	// on URB error, trigger immediate poll
	schedule_delayed_work(&dev->carrier_work, 0);
	}

	static int ipheth_carrier_set(struct ipheth_device *dev)
	{
	struct usb_device *udev;
	int retval;

	if (!dev->confirmed_pairing)
	return 0;

	udev = dev->udev;
	retval = usb_control_msg(udev,
	usb_rcvctrlpipe(udev, IPHETH_CTRL_ENDP),
	IPHETH_CMD_CARRIER_CHECK, /* request */
	0xc0, /* request type */
	0x00, /* value */
	0x02, /* index */
	dev->ctrl_buf, IPHETH_CTRL_BUF_SIZE,
	IPHETH_CTRL_TIMEOUT);
	if (retval < 0) {
	dev_err(&dev->intf->dev, "%s: usb_control_msg: %d\n",
	__func__, retval);
	return retval;
	}

	if (dev->ctrl_buf[0] == IPHETH_CARRIER_ON) {
	netif_carrier_on(dev->net);
	if (dev->tx_urb->status != -EINPROGRESS)
	netif_wake_queue(dev->net);
	} else {
	netif_carrier_off(dev->net);
	netif_stop_queue(dev->net);
	}
	return 0;
	}

	static void ipheth_carrier_check_work(struct work_struct *work)
	{
	struct ipheth_device *dev = container_of(work, struct ipheth_device,
	carrier_work.work);

	ipheth_carrier_set(dev);
	schedule_delayed_work(&dev->carrier_work, IPHETH_CARRIER_CHECK_TIMEOUT);
	}

	static int ipheth_get_macaddr(struct ipheth_device *dev)
	{
	struct usb_device *udev = dev->udev;
	struct net_device *net = dev->net;
	int retval;

	retval = usb_control_msg(udev,
	usb_rcvctrlpipe(udev, IPHETH_CTRL_ENDP),
	IPHETH_CMD_GET_MACADDR, /* request */
	0xc0, /* request type */
	0x00, /* value */
	0x02, /* index */
	dev->ctrl_buf,
	IPHETH_CTRL_BUF_SIZE,
	IPHETH_CTRL_TIMEOUT);
	if (retval < 0) {
	dev_err(&dev->intf->dev, "%s: usb_control_msg: %d\n",
	__func__, retval);
	} else if (retval < ETH_ALEN) {
	dev_err(&dev->intf->dev,
	"%s: usb_control_msg: short packet: %d bytes\n",
	__func__, retval);
	retval = -EINVAL;
	} else {
	memcpy(net->dev_addr, dev->ctrl_buf, ETH_ALEN);
	retval = 0;
	}

	return retval;
	}

	static int ipheth_rx_submit(struct ipheth_device *dev, gfp_t mem_flags)
	{
	struct usb_device *udev = dev->udev;
	int retval;

	usb_fill_bulk_urb(dev->rx_urb, udev,
	usb_rcvbulkpipe(udev, dev->bulk_in),
	dev->rx_buf, IPHETH_BUF_SIZE + IPHETH_IP_ALIGN,
	ipheth_rcvbulk_callback,
	dev);
	dev->rx_urb->transfer_flags \|= URB_NO_TRANSFER_DMA_MAP;

	retval = usb_submit_urb(dev->rx_urb, mem_flags);
	if (retval)
	dev_err(&dev->intf->dev, "%s: usb_submit_urb: %d\n",
	__func__, retval);
	return retval;
	}

	static int ipheth_open(struct net_device *net)
	{
	struct ipheth_device *dev = netdev_priv(net);
	struct usb_device *udev = dev->udev;
	int retval = 0;

	usb_set_interface(udev, IPHETH_INTFNUM, IPHETH_ALT_INTFNUM);

	retval = ipheth_carrier_set(dev);
	if (retval)
	return retval;

	retval = ipheth_rx_submit(dev, GFP_KERNEL);
	if (retval)
	return retval;

	schedule_delayed_work(&dev->carrier_work, IPHETH_CARRIER_CHECK_TIMEOUT);
	return retval;
	}

	static int ipheth_close(struct net_device *net)
	{
	struct ipheth_device *dev = netdev_priv(net);

	cancel_delayed_work_sync(&dev->carrier_work);
	netif_stop_queue(net);
	return 0;
	}

	static netdev_tx_t ipheth_tx(struct sk_buff skb, struct net_device net)
	{
	struct ipheth_device *dev = netdev_priv(net);
	struct usb_device *udev = dev->udev;
	int retval;

	/* Paranoid */
	if (skb->len > IPHETH_BUF_SIZE) {
	WARN(1, "%s: skb too large: %d bytes\n", __func__, skb->len);
	dev->net->stats.tx_dropped++;
	dev_kfree_skb_any(skb);
	return NETDEV_TX_OK;
	}

	memcpy(dev->tx_buf, skb->data, skb->len);
	if (skb->len < IPHETH_BUF_SIZE)
	memset(dev->tx_buf + skb->len, 0, IPHETH_BUF_SIZE - skb->len);

	usb_fill_bulk_urb(dev->tx_urb, udev,
	usb_sndbulkpipe(udev, dev->bulk_out),
	dev->tx_buf, IPHETH_BUF_SIZE,
	ipheth_sndbulk_callback,
	dev);
	dev->tx_urb->transfer_flags \|= URB_NO_TRANSFER_DMA_MAP;

	netif_stop_queue(net);
	retval = usb_submit_urb(dev->tx_urb, GFP_ATOMIC);
	if (retval) {
	dev_err(&dev->intf->dev, "%s: usb_submit_urb: %d\n",
	__func__, retval);
	dev->net->stats.tx_errors++;
	dev_kfree_skb_any(skb);
	netif_wake_queue(net);
	} else {
	dev->net->stats.tx_packets++;
	dev->net->stats.tx_bytes += skb->len;
	dev_consume_skb_any(skb);
	}

	return NETDEV_TX_OK;
	}

	static void ipheth_tx_timeout(struct net_device *net, unsigned int txqueue)
	{
	struct ipheth_device *dev = netdev_priv(net);

	dev_err(&dev->intf->dev, "%s: TX timeout\n", __func__);
	dev->net->stats.tx_errors++;
	usb_unlink_urb(dev->tx_urb);
	}

	static u32 ipheth_ethtool_op_get_link(struct net_device *net)
	{
	struct ipheth_device *dev = netdev_priv(net);
	return netif_carrier_ok(dev->net);
	}

	static const struct ethtool_ops ops = {
	.get_link = ipheth_ethtool_op_get_link
	};

	static const struct net_device_ops ipheth_netdev_ops = {
	.ndo_open = ipheth_open,
	.ndo_stop = ipheth_close,
	.ndo_start_xmit = ipheth_tx,
	.ndo_tx_timeout = ipheth_tx_timeout,
	};

	static int ipheth_probe(struct usb_interface *intf,
	const struct usb_device_id *id)
	{
	struct usb_device *udev = interface_to_usbdev(intf);
	struct usb_host_interface *hintf;
	struct usb_endpoint_descriptor *endp;
	struct ipheth_device *dev;
	struct net_device *netdev;
	int i;
	int retval;

	netdev = alloc_etherdev(sizeof(struct ipheth_device));
	if (!netdev)
	return -ENOMEM;

	netdev->netdev_ops = &ipheth_netdev_ops;
	netdev->watchdog_timeo = IPHETH_TX_TIMEOUT;
	strcpy(netdev->name, "eth%d");

	dev = netdev_priv(netdev);
	dev->udev = udev;
	dev->net = netdev;
	dev->intf = intf;
	dev->confirmed_pairing = false;
	/* Set up endpoints */
	hintf = usb_altnum_to_altsetting(intf, IPHETH_ALT_INTFNUM);
	if (hintf == NULL) {
	retval = -ENODEV;
	dev_err(&intf->dev, "Unable to find alternate settings interface\n");
	goto err_endpoints;
	}

	for (i = 0; i < hintf->desc.bNumEndpoints; i++) {
	endp = &hintf->endpoint[i].desc;
	if (usb_endpoint_is_bulk_in(endp))
	dev->bulk_in = endp->bEndpointAddress;
	else if (usb_endpoint_is_bulk_out(endp))
	dev->bulk_out = endp->bEndpointAddress;
	}
	if (!(dev->bulk_in && dev->bulk_out)) {
	retval = -ENODEV;
	dev_err(&intf->dev, "Unable to find endpoints\n");
	goto err_endpoints;
	}

	dev->ctrl_buf = kmalloc(IPHETH_CTRL_BUF_SIZE, GFP_KERNEL);
	if (dev->ctrl_buf == NULL) {
	retval = -ENOMEM;
	goto err_alloc_ctrl_buf;
	}

	retval = ipheth_get_macaddr(dev);
	if (retval)
	goto err_get_macaddr;

	INIT_DELAYED_WORK(&dev->carrier_work, ipheth_carrier_check_work);

	retval = ipheth_alloc_urbs(dev);
	if (retval) {
	dev_err(&intf->dev, "error allocating urbs: %d\n", retval);
	goto err_alloc_urbs;
	}

	usb_set_intfdata(intf, dev);

	SET_NETDEV_DEV(netdev, &intf->dev);
	netdev->ethtool_ops = &ops;

	retval = register_netdev(netdev);
	if (retval) {
	dev_err(&intf->dev, "error registering netdev: %d\n", retval);
	retval = -EIO;
	goto err_register_netdev;
	}
	// carrier down and transmit queues stopped until packet from device
	netif_carrier_off(netdev);
	netif_tx_stop_all_queues(netdev);
	dev_info(&intf->dev, "Apple iPhone USB Ethernet device attached\n");
	return 0;

	err_register_netdev:
	ipheth_free_urbs(dev);
	err_alloc_urbs:
	err_get_macaddr:
	err_alloc_ctrl_buf:
	kfree(dev->ctrl_buf);
	err_endpoints:
	free_netdev(netdev);
	return retval;
	}

	static void ipheth_disconnect(struct usb_interface *intf)
	{
	struct ipheth_device *dev;

	dev = usb_get_intfdata(intf);
	if (dev != NULL) {
	unregister_netdev(dev->net);
	ipheth_kill_urbs(dev);
	ipheth_free_urbs(dev);
	kfree(dev->ctrl_buf);
	free_netdev(dev->net);
	}
	usb_set_intfdata(intf, NULL);
	dev_info(&intf->dev, "Apple iPhone USB Ethernet now disconnected\n");
	}

	static struct usb_driver ipheth_driver = {
	.name = "ipheth",
	.probe = ipheth_probe,
	.disconnect = ipheth_disconnect,
	.id_table = ipheth_table,
	.disable_hub_initiated_lpm = 1,
	};

	module_usb_driver(ipheth_driver);

	MODULE_AUTHOR("Diego Giagio <diego@giagio.com>");
	MODULE_DESCRIPTION("Apple iPhone USB Ethernet driver");
	MODULE_LICENSE("Dual BSD/GPL");