iPhoneEthernetDriver

/*
 * 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/init.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 USB_PRODUCT_IPHONE      0x1290
#define USB_PRODUCT_IPHONE_3G   0x1292
#define USB_PRODUCT_IPHONE_3GS  0x1294
#define USB_PRODUCT_IPHONE_4    0x1297
#define USB_PRODUCT_IPAD 0x129a
#define USB_PRODUCT_IPHONE_4_VZW 0x129c
#define USB_PRODUCT_IPHONE_4S    0x12a0
#define USB_PRODUCT_IPHONE_5    0x12a8

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

#define IPHETH_BUF_SIZE         1516
#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 struct usb_device_id ipheth_table[] = {
    { USB_DEVICE_AND_INTERFACE_INFO(
                                    USB_VENDOR_APPLE, USB_PRODUCT_IPHONE,
                                    IPHETH_USBINTF_CLASS, IPHETH_USBINTF_SUBCLASS,
                                    IPHETH_USBINTF_PROTO) },
    { USB_DEVICE_AND_INTERFACE_INFO(
                                    USB_VENDOR_APPLE, USB_PRODUCT_IPHONE_3G,
                                    IPHETH_USBINTF_CLASS, IPHETH_USBINTF_SUBCLASS,
                                    IPHETH_USBINTF_PROTO) },
    { USB_DEVICE_AND_INTERFACE_INFO(
                                    USB_VENDOR_APPLE, USB_PRODUCT_IPHONE_3GS,
                                    IPHETH_USBINTF_CLASS, IPHETH_USBINTF_SUBCLASS,
                                    IPHETH_USBINTF_PROTO) },
    { USB_DEVICE_AND_INTERFACE_INFO(
                                    USB_VENDOR_APPLE, USB_PRODUCT_IPHONE_4,
                                    IPHETH_USBINTF_CLASS, IPHETH_USBINTF_SUBCLASS,
                                    IPHETH_USBINTF_PROTO) },
    { USB_DEVICE_AND_INTERFACE_INFO(
                                    USB_VENDOR_APPLE, USB_PRODUCT_IPAD,
                                    IPHETH_USBINTF_CLASS, IPHETH_USBINTF_SUBCLASS,
                                    IPHETH_USBINTF_PROTO) },
    { USB_DEVICE_AND_INTERFACE_INFO(
                                    USB_VENDOR_APPLE, USB_PRODUCT_IPHONE_4_VZW,
                                    IPHETH_USBINTF_CLASS, IPHETH_USBINTF_SUBCLASS,
                                    IPHETH_USBINTF_PROTO) },
    { USB_DEVICE_AND_INTERFACE_INFO(
                                    USB_VENDOR_APPLE, USB_PRODUCT_IPHONE_4S,
                                    IPHETH_USBINTF_CLASS, IPHETH_USBINTF_SUBCLASS,
                                    IPHETH_USBINTF_PROTO) },
    { USB_DEVICE_AND_INTERFACE_INFO(
                                    USB_VENDOR_APPLE, USB_PRODUCT_IPHONE_5,
                                    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 sk_buff *tx_skb;
    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;
};

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,
                                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, 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:
            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;
    }
    
    memcpy(skb_put(skb, len), 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;
    
    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);
    
    dev_kfree_skb_irq(dev->tx_skb);
    netif_wake_queue(dev->net);
}

static int ipheth_carrier_set(struct ipheth_device *dev)
{
    struct usb_device *udev = dev->udev;
    int retval;
    
    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);
    else
        netif_carrier_off(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_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);
    netif_start_queue(net);
    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 int 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_irq(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;
    
    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_irq(skb);
    } else {
        dev->tx_skb = skb;
        
        dev->net->stats.tx_packets++;
        dev->net->stats.tx_bytes += skb->len;
        netif_stop_queue(net);
    }
    
    return NETDEV_TX_OK;
}

static void ipheth_tx_timeout(struct net_device *net)
{
    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;
    
    /* 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);
    SET_ETHTOOL_OPS(netdev, &ops);
    
    retval = register_netdev(netdev);
    if (retval) {
        dev_err(&intf->dev, "error registering netdev: %d\n", retval);
        retval = -EIO;
        goto err_register_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");