// SPDX-License-Identifier: GPL-2.0+
/*
 * cdc2.c -- CDC Composite driver, with ECM and ACM support
 *
 * Copyright (C) 2008 David Brownell
 * Copyright (C) 2008 Nokia Corporation
 */

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

#include "u_ether.h"
#include "u_serial.h"
#include "u_ecm.h"


#define DRIVER_DESC             "CDC Composite Gadget"
#define DRIVER_VERSION          "King Kamehameha Day 2008"

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

/* 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 this composite CDC configuration.
 */
#define CDC_VENDOR_NUM          0x0525  /* NetChip */
#define CDC_PRODUCT_NUM         0xa4aa  /* CDC Composite: ECM + ACM */

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 can 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 *f_acm;
static struct usb_function_instance *fi_serial;

static struct usb_function *f_ecm;
static struct usb_function_instance *fi_ecm;

/*
 * We _always_ have both CDC ECM and CDC ACM functions.
 */
static int cdc_do_config(struct usb_configuration *c)
{
        int     status;

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

        f_ecm = usb_get_function(fi_ecm);
        if (IS_ERR(f_ecm)) {
                status = PTR_ERR(f_ecm);
                goto err_get_ecm;
        }

        status = usb_add_function(c, f_ecm);
        if (status)
                goto err_add_ecm;

        f_acm = usb_get_function(fi_serial);
        if (IS_ERR(f_acm)) {
                status = PTR_ERR(f_acm);
                goto err_get_acm;
        }

        status = usb_add_function(c, f_acm);
        if (status)
                goto err_add_acm;
        return 0;

err_add_acm:
        usb_put_function(f_acm);
err_get_acm:
        usb_remove_function(c, f_ecm);
err_add_ecm:
        usb_put_function(f_ecm);
err_get_ecm:
        return status;
}

static struct usb_configuration cdc_config_driver = {
        .label                  = "CDC Composite (ECM + ACM)",
        .bConfigurationValue    = 1,
        /* .iConfiguration = DYNAMIC */
        .bmAttributes           = USB_CONFIG_ATT_SELFPOWER,
};

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

static int cdc_bind(struct usb_composite_dev *cdev)
{
        struct usb_gadget       *gadget = cdev->gadget;
        struct f_ecm_opts       *ecm_opts;
        int                     status;

        if (!can_support_ecm(cdev->gadget)) {
                dev_err(&gadget->dev, "controller '%s' not usable\n",
                                gadget->name);
                return -EINVAL;
        }

        fi_ecm = usb_get_function_instance("ecm");
        if (IS_ERR(fi_ecm))
                return PTR_ERR(fi_ecm);

        ecm_opts = container_of(fi_ecm, struct f_ecm_opts, func_inst);

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

        fi_serial = usb_get_function_instance("acm");
        if (IS_ERR(fi_serial)) {
                status = PTR_ERR(fi_serial);
                goto fail;
        }

        /* 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 fail1;
        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)
                        goto fail1;
                usb_otg_descriptor_init(gadget, usb_desc);
                otg_desc[0] = usb_desc;
                otg_desc[1] = NULL;
        }

        /* register our configuration */
        status = usb_add_config(cdev, &cdc_config_driver, cdc_do_config);
        if (status < 0)
                goto fail2;

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

        return 0;

fail2:
        kfree(otg_desc[0]);
        otg_desc[0] = NULL;
fail1:
        usb_put_function_instance(fi_serial);
fail:
        usb_put_function_instance(fi_ecm);
        return status;
}

static int cdc_unbind(struct usb_composite_dev *cdev)
{
        usb_put_function(f_acm);
        usb_put_function_instance(fi_serial);
        if (!IS_ERR_OR_NULL(f_ecm))
                usb_put_function(f_ecm);
        if (!IS_ERR_OR_NULL(fi_ecm))
                usb_put_function_instance(fi_ecm);
        kfree(otg_desc[0]);
        otg_desc[0] = NULL;

        return 0;
}

static struct usb_composite_driver cdc_driver = {
        .name           = "g_cdc",
        .dev            = &device_desc,
        .strings        = dev_strings,
        .max_speed      = USB_SPEED_HIGH,
        .bind           = cdc_bind,
        .unbind         = cdc_unbind,
};

module_usb_composite_driver(cdc_driver);

MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_AUTHOR("David Brownell");
MODULE_LICENSE("GPL");