// SPDX-License-Identifier: GPL-2.0+
/*
 * 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
 */

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

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

#include "u_ether.h"
#include "u_ncm.h"

#define DRIVER_DESC             "NCM Gadget"

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

/* 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();

USB_ETHERNET_MODULE_PARAMETERS();

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

        /* .bcdUSB = DYNAMIC */

        .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 const struct usb_descriptor_header *otg_desc[2];

/* 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 struct usb_function_instance *f_ncm_inst;
static struct usb_function *f_ncm;

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

static int ncm_do_config(struct usb_configuration *c)
{
        int status;

        /* 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;
        }

        f_ncm = usb_get_function(f_ncm_inst);
        if (IS_ERR(f_ncm))
                return PTR_ERR(f_ncm);

        status = usb_add_function(c, f_ncm);
        if (status < 0) {
                usb_put_function(f_ncm);
                return status;
        }

        return 0;
}

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

        f_ncm_inst = usb_get_function_instance("ncm");
        if (IS_ERR(f_ncm_inst))
                return PTR_ERR(f_ncm_inst);

        ncm_opts = container_of(f_ncm_inst, struct f_ncm_opts, func_inst);

        gether_set_qmult(ncm_opts->net, qmult);
        if (!gether_set_host_addr(ncm_opts->net, host_addr))
                pr_info("using host ethernet address: %s", host_addr);
        if (!gether_set_dev_addr(ncm_opts->net, dev_addr))
                pr_info("using self ethernet address: %s", dev_addr);

        /* 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;

        if (gadget_is_otg(gadget) && !otg_desc[0]) {
                struct usb_descriptor_header *usb_desc;

                usb_desc = usb_otg_descriptor_alloc(gadget);
                if (!usb_desc) {
                        status = -ENOMEM;
                        goto fail;
                }
                usb_otg_descriptor_init(gadget, usb_desc);
                otg_desc[0] = usb_desc;
                otg_desc[1] = NULL;
        }

        status = usb_add_config(cdev, &ncm_config_driver,
                                ncm_do_config);
        if (status < 0)
                goto fail1;

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

        return 0;

fail1:
        kfree(otg_desc[0]);
        otg_desc[0] = NULL;
fail:
        usb_put_function_instance(f_ncm_inst);
        return status;
}

static int gncm_unbind(struct usb_composite_dev *cdev)
{
        if (!IS_ERR_OR_NULL(f_ncm))
                usb_put_function(f_ncm);
        if (!IS_ERR_OR_NULL(f_ncm_inst))
                usb_put_function_instance(f_ncm_inst);
        kfree(otg_desc[0]);
        otg_desc[0] = NULL;

        return 0;
}

static struct usb_composite_driver ncm_driver = {
        .name           = "g_ncm",
        .dev            = &device_desc,
        .strings        = dev_strings,
        .max_speed      = USB_SPEED_SUPER,
        .bind           = gncm_bind,
        .unbind         = gncm_unbind,
};

module_usb_composite_driver(ncm_driver);

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