cdc-phonet.c

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/*
 * 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/mm.h>
#include <linux/module.h>
#include <linux/gfp.h>
#include <linux/usb.h>
#include <linux/usb/cdc.h>
#include <linux/netdevice.h>
#include <linux/if_arp.h>
#include <linux/if_phonet.h>
#include <linux/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);
    int status = req->status;

    switch (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", 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 = __skb_alloc_page(gfp_flags | __GFP_NOMEMALLOC, NULL);
    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);
        put_page(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;
    int status = req->status;

    switch (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_SIZE);
                page = NULL;
            }
        } else {
            skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags,
                    page, 0, req->actual_length,
                    PAGE_SIZE);
            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)
        put_page(page);
    if (req)
        rx_submit(pnd, req, GFP_ATOMIC | __GFP_COLD);
}

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 | __GFP_COLD)) {
            usb_free_urb(req);
            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_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
{
    struct if_phonet_req *req = (struct if_phonet_req *)ifr;

    switch (cmd) {
    case SIOCPNGAUTOCONF:
        req->ifr_phonet_autoconf.device = PN_DEV_PC;
        return 0;
    }
    return -ENOIOCTLCMD;
}

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_do_ioctl   = usbpn_ioctl,
    .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_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 phonet = 0;
    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:
                phonet = 1;
                break;
            }
        }
        data += dlen;
        len -= dlen;
    }

    if (!union_header || !phonet)
        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);

    pnd->dev = dev;
    pnd->usb = 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);

    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);
}

static struct usb_driver usbpn_driver = {
    .name =     "cdc_phonet",
    .probe =    usbpn_probe,
    .disconnect =   usbpn_disconnect,
    .id_table = usbpn_ids,
    .disable_hub_initiated_lpm = 1,
};

module_usb_driver(usbpn_driver);

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