ncm.c

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/*
 * ncm.c -- NCM gadget driver
 *
 * Copyright (C) 2010 Nokia Corporation
 * Contact: Yauheni Kaliuta <yauheni.kaliuta@nokia.com>
 *
 * The driver borrows from ether.c which is:
 *
 * Copyright (C) 2003-2005,2008 David Brownell
 * Copyright (C) 2003-2004 Robert Schwebel, Benedikt Spranger
 * Copyright (C) 2008 Nokia Corporation
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 */

/* #define DEBUG */
/* #define VERBOSE_DEBUG */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/usb/composite.h>

#include "u_ether.h"

#define DRIVER_DESC     "NCM Gadget"

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

/*
 * Kbuild is not very cooperative with respect to linking separately
 * compiled library objects into one module.  So for now we won't use
 * separate compilation ... ensuring init/exit sections work to shrink
 * the runtime footprint, and giving us at least some parts of what
 * a "gcc --combine ... part1.c part2.c part3.c ... " build would.
 */
#include "f_ncm.c"
#include "u_ether.c"

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

/* DO NOT REUSE THESE IDs with a protocol-incompatible driver!!  Ever!!
 * Instead:  allocate your own, using normal USB-IF procedures.
 */

/* Thanks to NetChip Technologies for donating this product ID.
 * It's for devices with only CDC Ethernet configurations.
 */
#define CDC_VENDOR_NUM      0x0525  /* NetChip */
#define CDC_PRODUCT_NUM     0xa4a1  /* Linux-USB Ethernet Gadget */

/*-------------------------------------------------------------------------*/
USB_GADGET_COMPOSITE_OPTIONS();

static struct usb_device_descriptor device_desc = {
    .bLength =      sizeof device_desc,
    .bDescriptorType =  USB_DT_DEVICE,

    .bcdUSB =       cpu_to_le16 (0x0200),

    .bDeviceClass =     USB_CLASS_COMM,
    .bDeviceSubClass =  0,
    .bDeviceProtocol =  0,
    /* .bMaxPacketSize0 = f(hardware) */

    /* Vendor and product id defaults change according to what configs
     * we support.  (As does bNumConfigurations.)  These values can
     * also be overridden by module parameters.
     */
    .idVendor =     cpu_to_le16 (CDC_VENDOR_NUM),
    .idProduct =        cpu_to_le16 (CDC_PRODUCT_NUM),
    /* .bcdDevice = f(hardware) */
    /* .iManufacturer = DYNAMIC */
    /* .iProduct = DYNAMIC */
    /* NO SERIAL NUMBER */
    .bNumConfigurations =   1,
};

static struct usb_otg_descriptor otg_descriptor = {
    .bLength =      sizeof otg_descriptor,
    .bDescriptorType =  USB_DT_OTG,

    /* REVISIT SRP-only hardware is possible, although
     * it would not be called "OTG" ...
     */
    .bmAttributes =     USB_OTG_SRP | USB_OTG_HNP,
};

static const struct usb_descriptor_header *otg_desc[] = {
    (struct usb_descriptor_header *) &otg_descriptor,
    NULL,
};

/* string IDs are assigned dynamically */
static struct usb_string strings_dev[] = {
    [USB_GADGET_MANUFACTURER_IDX].s = "",
    [USB_GADGET_PRODUCT_IDX].s = DRIVER_DESC,
    [USB_GADGET_SERIAL_IDX].s = "",
    {  } /* end of list */
};

static struct usb_gadget_strings stringtab_dev = {
    .language   = 0x0409,   /* en-us */
    .strings    = strings_dev,
};

static struct usb_gadget_strings *dev_strings[] = {
    &stringtab_dev,
    NULL,
};

static u8 hostaddr[ETH_ALEN];

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

static int __init ncm_do_config(struct usb_configuration *c)
{
    /* FIXME alloc iConfiguration string, set it in c->strings */

    if (gadget_is_otg(c->cdev->gadget)) {
        c->descriptors = otg_desc;
        c->bmAttributes |= USB_CONFIG_ATT_WAKEUP;
    }

    return ncm_bind_config(c, hostaddr);
}

static struct usb_configuration ncm_config_driver = {
    /* .label = f(hardware) */
    .label          = "CDC Ethernet (NCM)",
    .bConfigurationValue    = 1,
    /* .iConfiguration = DYNAMIC */
    .bmAttributes       = USB_CONFIG_ATT_SELFPOWER,
};

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

static int __init gncm_bind(struct usb_composite_dev *cdev)
{
    struct usb_gadget   *gadget = cdev->gadget;
    int         status;

    /* set up network link layer */
    status = gether_setup(cdev->gadget, hostaddr);
    if (status < 0)
        return status;

    /* Allocate string descriptor numbers ... note that string
     * contents can be overridden by the composite_dev glue.
     */

    status = usb_string_ids_tab(cdev, strings_dev);
    if (status < 0)
        goto fail;
    device_desc.iManufacturer = strings_dev[USB_GADGET_MANUFACTURER_IDX].id;
    device_desc.iProduct = strings_dev[USB_GADGET_PRODUCT_IDX].id;

    status = usb_add_config(cdev, &ncm_config_driver,
                ncm_do_config);
    if (status < 0)
        goto fail;

    usb_composite_overwrite_options(cdev, &coverwrite);
    dev_info(&gadget->dev, "%s\n", DRIVER_DESC);

    return 0;

fail:
    gether_cleanup();
    return status;
}

static int __exit gncm_unbind(struct usb_composite_dev *cdev)
{
    gether_cleanup();
    return 0;
}

static __refdata struct usb_composite_driver ncm_driver = {
    .name       = "g_ncm",
    .dev        = &device_desc,
    .strings    = dev_strings,
    .max_speed  = USB_SPEED_HIGH,
    .bind       = gncm_bind,
    .unbind     = __exit_p(gncm_unbind),
};

MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_AUTHOR("Yauheni Kaliuta");
MODULE_LICENSE("GPL");

static int __init init(void)
{
    return usb_composite_probe(&ncm_driver);
}
module_init(init);

static void __exit cleanup(void)
{
    usb_composite_unregister(&ncm_driver);
}
module_exit(cleanup);