/*
 * 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/utsname.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 "composite.c"
#include "usbstring.c"
#include "config.c"
#include "epautoconf.c"

#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 */

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

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 */

#define STRING_MANUFACTURER_IDX         0
#define STRING_PRODUCT_IDX              1

static char manufacturer[50];

static struct usb_string strings_dev[] = {
        [STRING_MANUFACTURER_IDX].s = manufacturer,
        [STRING_PRODUCT_IDX].s = DRIVER_DESC,
        {  } /* 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)
{
        int                     gcnum;
        struct usb_gadget       *gadget = cdev->gadget;
        int                     status;

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

        gcnum = usb_gadget_controller_number(gadget);
        if (gcnum >= 0)
                device_desc.bcdDevice = cpu_to_le16(0x0300 | gcnum);
        else {
                /* We assume that can_support_ecm() tells the truth;
                 * but if the controller isn't recognized at all then
                 * that assumption is a bit more likely to be wrong.
                 */
                dev_warn(&gadget->dev,
                         "controller '%s' not recognized; trying %s\n",
                         gadget->name,
                         ncm_config_driver.label);
                device_desc.bcdDevice =
                        cpu_to_le16(0x0300 | 0x0099);
        }


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

        /* device descriptor strings: manufacturer, product */
        snprintf(manufacturer, sizeof manufacturer, "%s %s with %s",
                init_utsname()->sysname, init_utsname()->release,
                gadget->name);
        status = usb_string_id(cdev);
        if (status < 0)
                goto fail;
        strings_dev[STRING_MANUFACTURER_IDX].id = status;
        device_desc.iManufacturer = status;

        status = usb_string_id(cdev);
        if (status < 0)
                goto fail;
        strings_dev[STRING_PRODUCT_IDX].id = status;
        device_desc.iProduct = status;

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

        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 struct usb_composite_driver ncm_driver = {
        .name           = "g_ncm",
        .dev            = &device_desc,
        .strings        = dev_strings,
        .max_speed      = USB_SPEED_HIGH,
        .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, gncm_bind);
}
module_init(init);

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