f_phonet.c

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/*
 * f_phonet.c -- USB CDC Phonet function
 *
 * Copyright (C) 2007-2008 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.
 */

#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/kernel.h>
#include <linux/device.h>

#include <linux/netdevice.h>
#include <linux/if_ether.h>
#include <linux/if_phonet.h>
#include <linux/if_arp.h>

#include <linux/usb/ch9.h>
#include <linux/usb/cdc.h>
#include <linux/usb/composite.h>

#include "u_phonet.h"

#define PN_MEDIA_USB    0x1B
#define MAXPACKET   512
#if (PAGE_SIZE % MAXPACKET)
#error MAXPACKET must divide PAGE_SIZE!
#endif

/*-------------------------------------------------------------------------*/

struct phonet_port {
    struct f_phonet         *usb;
    spinlock_t          lock;
};

struct f_phonet {
    struct usb_function     function;
    struct {
        struct sk_buff      *skb;
        spinlock_t      lock;
    } rx;
    struct net_device       *dev;
    struct usb_ep           *in_ep, *out_ep;

    struct usb_request      *in_req;
    struct usb_request      *out_reqv[0];
};

static int phonet_rxq_size = 17;

static inline struct f_phonet *func_to_pn(struct usb_function *f)
{
    return container_of(f, struct f_phonet, function);
}

/*-------------------------------------------------------------------------*/

#define USB_CDC_SUBCLASS_PHONET 0xfe
#define USB_CDC_PHONET_TYPE 0xab

static struct usb_interface_descriptor
pn_control_intf_desc = {
    .bLength =      sizeof pn_control_intf_desc,
    .bDescriptorType =  USB_DT_INTERFACE,

    /* .bInterfaceNumber =  DYNAMIC, */
    .bInterfaceClass =  USB_CLASS_COMM,
    .bInterfaceSubClass =   USB_CDC_SUBCLASS_PHONET,
};

static const struct usb_cdc_header_desc
pn_header_desc = {
    .bLength =      sizeof pn_header_desc,
    .bDescriptorType =  USB_DT_CS_INTERFACE,
    .bDescriptorSubType =   USB_CDC_HEADER_TYPE,
    .bcdCDC =       cpu_to_le16(0x0110),
};

static const struct usb_cdc_header_desc
pn_phonet_desc = {
    .bLength =      sizeof pn_phonet_desc,
    .bDescriptorType =  USB_DT_CS_INTERFACE,
    .bDescriptorSubType =   USB_CDC_PHONET_TYPE,
    .bcdCDC =       cpu_to_le16(0x1505), /* ??? */
};

static struct usb_cdc_union_desc
pn_union_desc = {
    .bLength =      sizeof pn_union_desc,
    .bDescriptorType =  USB_DT_CS_INTERFACE,
    .bDescriptorSubType =   USB_CDC_UNION_TYPE,

    /* .bMasterInterface0 = DYNAMIC, */
    /* .bSlaveInterface0 =  DYNAMIC, */
};

static struct usb_interface_descriptor
pn_data_nop_intf_desc = {
    .bLength =      sizeof pn_data_nop_intf_desc,
    .bDescriptorType =  USB_DT_INTERFACE,

    /* .bInterfaceNumber =  DYNAMIC, */
    .bAlternateSetting =    0,
    .bNumEndpoints =    0,
    .bInterfaceClass =  USB_CLASS_CDC_DATA,
};

static struct usb_interface_descriptor
pn_data_intf_desc = {
    .bLength =      sizeof pn_data_intf_desc,
    .bDescriptorType =  USB_DT_INTERFACE,

    /* .bInterfaceNumber =  DYNAMIC, */
    .bAlternateSetting =    1,
    .bNumEndpoints =    2,
    .bInterfaceClass =  USB_CLASS_CDC_DATA,
};

static struct usb_endpoint_descriptor
pn_fs_sink_desc = {
    .bLength =      USB_DT_ENDPOINT_SIZE,
    .bDescriptorType =  USB_DT_ENDPOINT,

    .bEndpointAddress = USB_DIR_OUT,
    .bmAttributes =     USB_ENDPOINT_XFER_BULK,
};

static struct usb_endpoint_descriptor
pn_hs_sink_desc = {
    .bLength =      USB_DT_ENDPOINT_SIZE,
    .bDescriptorType =  USB_DT_ENDPOINT,

    .bEndpointAddress = USB_DIR_OUT,
    .bmAttributes =     USB_ENDPOINT_XFER_BULK,
    .wMaxPacketSize =   cpu_to_le16(MAXPACKET),
};

static struct usb_endpoint_descriptor
pn_fs_source_desc = {
    .bLength =      USB_DT_ENDPOINT_SIZE,
    .bDescriptorType =  USB_DT_ENDPOINT,

    .bEndpointAddress = USB_DIR_IN,
    .bmAttributes =     USB_ENDPOINT_XFER_BULK,
};

static struct usb_endpoint_descriptor
pn_hs_source_desc = {
    .bLength =      USB_DT_ENDPOINT_SIZE,
    .bDescriptorType =  USB_DT_ENDPOINT,

    .bEndpointAddress = USB_DIR_IN,
    .bmAttributes =     USB_ENDPOINT_XFER_BULK,
    .wMaxPacketSize =   cpu_to_le16(512),
};

static struct usb_descriptor_header *fs_pn_function[] = {
    (struct usb_descriptor_header *) &pn_control_intf_desc,
    (struct usb_descriptor_header *) &pn_header_desc,
    (struct usb_descriptor_header *) &pn_phonet_desc,
    (struct usb_descriptor_header *) &pn_union_desc,
    (struct usb_descriptor_header *) &pn_data_nop_intf_desc,
    (struct usb_descriptor_header *) &pn_data_intf_desc,
    (struct usb_descriptor_header *) &pn_fs_sink_desc,
    (struct usb_descriptor_header *) &pn_fs_source_desc,
    NULL,
};

static struct usb_descriptor_header *hs_pn_function[] = {
    (struct usb_descriptor_header *) &pn_control_intf_desc,
    (struct usb_descriptor_header *) &pn_header_desc,
    (struct usb_descriptor_header *) &pn_phonet_desc,
    (struct usb_descriptor_header *) &pn_union_desc,
    (struct usb_descriptor_header *) &pn_data_nop_intf_desc,
    (struct usb_descriptor_header *) &pn_data_intf_desc,
    (struct usb_descriptor_header *) &pn_hs_sink_desc,
    (struct usb_descriptor_header *) &pn_hs_source_desc,
    NULL,
};

/*-------------------------------------------------------------------------*/

static int pn_net_open(struct net_device *dev)
{
    netif_wake_queue(dev);
    return 0;
}

static int pn_net_close(struct net_device *dev)
{
    netif_stop_queue(dev);
    return 0;
}

static void pn_tx_complete(struct usb_ep *ep, struct usb_request *req)
{
    struct f_phonet *fp = ep->driver_data;
    struct net_device *dev = fp->dev;
    struct sk_buff *skb = req->context;

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

    case -ESHUTDOWN: /* disconnected */
    case -ECONNRESET: /* disabled */
        dev->stats.tx_aborted_errors++;
    default:
        dev->stats.tx_errors++;
    }

    dev_kfree_skb_any(skb);
    netif_wake_queue(dev);
}

static int pn_net_xmit(struct sk_buff *skb, struct net_device *dev)
{
    struct phonet_port *port = netdev_priv(dev);
    struct f_phonet *fp;
    struct usb_request *req;
    unsigned long flags;

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

    spin_lock_irqsave(&port->lock, flags);
    fp = port->usb;
    if (unlikely(!fp)) /* race with carrier loss */
        goto out_unlock;

    req = fp->in_req;
    req->buf = skb->data;
    req->length = skb->len;
    req->complete = pn_tx_complete;
    req->zero = 1;
    req->context = skb;

    if (unlikely(usb_ep_queue(fp->in_ep, req, GFP_ATOMIC)))
        goto out_unlock;

    netif_stop_queue(dev);
    skb = NULL;

out_unlock:
    spin_unlock_irqrestore(&port->lock, flags);
out:
    if (unlikely(skb)) {
        dev_kfree_skb(skb);
        dev->stats.tx_dropped++;
    }
    return NETDEV_TX_OK;
}

static int pn_net_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 pn_netdev_ops = {
    .ndo_open   = pn_net_open,
    .ndo_stop   = pn_net_close,
    .ndo_start_xmit = pn_net_xmit,
    .ndo_change_mtu = pn_net_mtu,
};

static void pn_net_setup(struct net_device *dev)
{
    dev->features       = 0;
    dev->type       = ARPHRD_PHONET;
    dev->flags      = IFF_POINTOPOINT | IFF_NOARP;
    dev->mtu        = PHONET_DEV_MTU;
    dev->hard_header_len    = 1;
    dev->dev_addr[0]    = PN_MEDIA_USB;
    dev->addr_len       = 1;
    dev->tx_queue_len   = 1;

    dev->netdev_ops     = &pn_netdev_ops;
    dev->destructor     = free_netdev;
    dev->header_ops     = &phonet_header_ops;
}

/*-------------------------------------------------------------------------*/

/*
 * Queue buffer for data from the host
 */
static int
pn_rx_submit(struct f_phonet *fp, struct usb_request *req, gfp_t gfp_flags)
{
    struct page *page;
    int err;

    page = __skb_alloc_page(gfp_flags | __GFP_NOMEMALLOC, NULL);
    if (!page)
        return -ENOMEM;

    req->buf = page_address(page);
    req->length = PAGE_SIZE;
    req->context = page;

    err = usb_ep_queue(fp->out_ep, req, gfp_flags);
    if (unlikely(err))
        put_page(page);
    return err;
}

static void pn_rx_complete(struct usb_ep *ep, struct usb_request *req)
{
    struct f_phonet *fp = ep->driver_data;
    struct net_device *dev = fp->dev;
    struct page *page = req->context;
    struct sk_buff *skb;
    unsigned long flags;
    int status = req->status;

    switch (status) {
    case 0:
        spin_lock_irqsave(&fp->rx.lock, flags);
        skb = fp->rx.skb;
        if (!skb)
            skb = fp->rx.skb = netdev_alloc_skb(dev, 12);
        if (req->actual < req->length) /* Last fragment */
            fp->rx.skb = NULL;
        spin_unlock_irqrestore(&fp->rx.lock, flags);

        if (unlikely(!skb))
            break;

        if (skb->len == 0) { /* First fragment */
            skb->protocol = htons(ETH_P_PHONET);
            skb_reset_mac_header(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,
                skb->len <= 1, req->actual, PAGE_SIZE);
        page = NULL;

        if (req->actual < req->length) { /* Last fragment */
            skb->dev = dev;
            dev->stats.rx_packets++;
            dev->stats.rx_bytes += skb->len;

            netif_rx(skb);
        }
        break;

    /* Do not resubmit in these cases: */
    case -ESHUTDOWN: /* disconnect */
    case -ECONNABORTED: /* hw reset */
    case -ECONNRESET: /* dequeued (unlink or netif down) */
        req = NULL;
        break;

    /* Do resubmit in these cases: */
    case -EOVERFLOW: /* request buffer overflow */
        dev->stats.rx_over_errors++;
    default:
        dev->stats.rx_errors++;
        break;
    }

    if (page)
        put_page(page);
    if (req)
        pn_rx_submit(fp, req, GFP_ATOMIC | __GFP_COLD);
}

/*-------------------------------------------------------------------------*/

static void __pn_reset(struct usb_function *f)
{
    struct f_phonet *fp = func_to_pn(f);
    struct net_device *dev = fp->dev;
    struct phonet_port *port = netdev_priv(dev);

    netif_carrier_off(dev);
    port->usb = NULL;

    usb_ep_disable(fp->out_ep);
    usb_ep_disable(fp->in_ep);
    if (fp->rx.skb) {
        dev_kfree_skb_irq(fp->rx.skb);
        fp->rx.skb = NULL;
    }
}

static int pn_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
{
    struct f_phonet *fp = func_to_pn(f);
    struct usb_gadget *gadget = fp->function.config->cdev->gadget;

    if (intf == pn_control_intf_desc.bInterfaceNumber)
        /* control interface, no altsetting */
        return (alt > 0) ? -EINVAL : 0;

    if (intf == pn_data_intf_desc.bInterfaceNumber) {
        struct net_device *dev = fp->dev;
        struct phonet_port *port = netdev_priv(dev);

        /* data intf (0: inactive, 1: active) */
        if (alt > 1)
            return -EINVAL;

        spin_lock(&port->lock);
        __pn_reset(f);
        if (alt == 1) {
            int i;

            if (config_ep_by_speed(gadget, f, fp->in_ep) ||
                config_ep_by_speed(gadget, f, fp->out_ep)) {
                fp->in_ep->desc = NULL;
                fp->out_ep->desc = NULL;
                spin_unlock(&port->lock);
                return -EINVAL;
            }
            usb_ep_enable(fp->out_ep);
            usb_ep_enable(fp->in_ep);

            port->usb = fp;
            fp->out_ep->driver_data = fp;
            fp->in_ep->driver_data = fp;

            netif_carrier_on(dev);
            for (i = 0; i < phonet_rxq_size; i++)
                pn_rx_submit(fp, fp->out_reqv[i], GFP_ATOMIC | __GFP_COLD);
        }
        spin_unlock(&port->lock);
        return 0;
    }

    return -EINVAL;
}

static int pn_get_alt(struct usb_function *f, unsigned intf)
{
    struct f_phonet *fp = func_to_pn(f);

    if (intf == pn_control_intf_desc.bInterfaceNumber)
        return 0;

    if (intf == pn_data_intf_desc.bInterfaceNumber) {
        struct phonet_port *port = netdev_priv(fp->dev);
        u8 alt;

        spin_lock(&port->lock);
        alt = port->usb != NULL;
        spin_unlock(&port->lock);
        return alt;
    }

    return -EINVAL;
}

static void pn_disconnect(struct usb_function *f)
{
    struct f_phonet *fp = func_to_pn(f);
    struct phonet_port *port = netdev_priv(fp->dev);
    unsigned long flags;

    /* remain disabled until set_alt */
    spin_lock_irqsave(&port->lock, flags);
    __pn_reset(f);
    spin_unlock_irqrestore(&port->lock, flags);
}

/*-------------------------------------------------------------------------*/

static __init
int pn_bind(struct usb_configuration *c, struct usb_function *f)
{
    struct usb_composite_dev *cdev = c->cdev;
    struct usb_gadget *gadget = cdev->gadget;
    struct f_phonet *fp = func_to_pn(f);
    struct usb_ep *ep;
    int status, i;

    /* Reserve interface IDs */
    status = usb_interface_id(c, f);
    if (status < 0)
        goto err;
    pn_control_intf_desc.bInterfaceNumber = status;
    pn_union_desc.bMasterInterface0 = status;

    status = usb_interface_id(c, f);
    if (status < 0)
        goto err;
    pn_data_nop_intf_desc.bInterfaceNumber = status;
    pn_data_intf_desc.bInterfaceNumber = status;
    pn_union_desc.bSlaveInterface0 = status;

    /* Reserve endpoints */
    status = -ENODEV;
    ep = usb_ep_autoconfig(gadget, &pn_fs_sink_desc);
    if (!ep)
        goto err;
    fp->out_ep = ep;
    ep->driver_data = fp; /* Claim */

    ep = usb_ep_autoconfig(gadget, &pn_fs_source_desc);
    if (!ep)
        goto err;
    fp->in_ep = ep;
    ep->driver_data = fp; /* Claim */

    pn_hs_sink_desc.bEndpointAddress =
        pn_fs_sink_desc.bEndpointAddress;
    pn_hs_source_desc.bEndpointAddress =
        pn_fs_source_desc.bEndpointAddress;

    /* Do not try to bind Phonet twice... */
    fp->function.descriptors = fs_pn_function;
    fp->function.hs_descriptors = hs_pn_function;

    /* Incoming USB requests */
    status = -ENOMEM;
    for (i = 0; i < phonet_rxq_size; i++) {
        struct usb_request *req;

        req = usb_ep_alloc_request(fp->out_ep, GFP_KERNEL);
        if (!req)
            goto err;

        req->complete = pn_rx_complete;
        fp->out_reqv[i] = req;
    }

    /* Outgoing USB requests */
    fp->in_req = usb_ep_alloc_request(fp->in_ep, GFP_KERNEL);
    if (!fp->in_req)
        goto err;

    INFO(cdev, "USB CDC Phonet function\n");
    INFO(cdev, "using %s, OUT %s, IN %s\n", cdev->gadget->name,
        fp->out_ep->name, fp->in_ep->name);
    return 0;

err:
    if (fp->out_ep)
        fp->out_ep->driver_data = NULL;
    if (fp->in_ep)
        fp->in_ep->driver_data = NULL;
    ERROR(cdev, "USB CDC Phonet: cannot autoconfigure\n");
    return status;
}

static void
pn_unbind(struct usb_configuration *c, struct usb_function *f)
{
    struct f_phonet *fp = func_to_pn(f);
    int i;

    /* We are already disconnected */
    if (fp->in_req)
        usb_ep_free_request(fp->in_ep, fp->in_req);
    for (i = 0; i < phonet_rxq_size; i++)
        if (fp->out_reqv[i])
            usb_ep_free_request(fp->out_ep, fp->out_reqv[i]);

    kfree(fp);
}

/*-------------------------------------------------------------------------*/

static struct net_device *dev;

int __init phonet_bind_config(struct usb_configuration *c)
{
    struct f_phonet *fp;
    int err, size;

    size = sizeof(*fp) + (phonet_rxq_size * sizeof(struct usb_request *));
    fp = kzalloc(size, GFP_KERNEL);
    if (!fp)
        return -ENOMEM;

    fp->dev = dev;
    fp->function.name = "phonet";
    fp->function.bind = pn_bind;
    fp->function.unbind = pn_unbind;
    fp->function.set_alt = pn_set_alt;
    fp->function.get_alt = pn_get_alt;
    fp->function.disable = pn_disconnect;
    spin_lock_init(&fp->rx.lock);

    err = usb_add_function(c, &fp->function);
    if (err)
        kfree(fp);
    return err;
}

int __init gphonet_setup(struct usb_gadget *gadget)
{
    struct phonet_port *port;
    int err;

    /* Create net device */
    BUG_ON(dev);
    dev = alloc_netdev(sizeof(*port), "upnlink%d", pn_net_setup);
    if (!dev)
        return -ENOMEM;

    port = netdev_priv(dev);
    spin_lock_init(&port->lock);
    netif_carrier_off(dev);
    SET_NETDEV_DEV(dev, &gadget->dev);

    err = register_netdev(dev);
    if (err)
        free_netdev(dev);
    return err;
}

void gphonet_cleanup(void)
{
    unregister_netdev(dev);
}