// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Copyright (c) 2009 Peter Holik
 *
 * Intellon usb PLC (Powerline Communications) usb net driver
 *
 * https://web.archive.org/web/20101025091240id_/http://www.tandel.be/downloads/INT51X1_Datasheet.pdf
 *
 * Based on the work of Jan 'RedBully' Seiffert
 */

#include <linux/module.h>
#include <linux/ctype.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/ethtool.h>
#include <linux/slab.h>
#include <linux/mii.h>
#include <linux/usb.h>
#include <linux/usb/usbnet.h>

#define INT51X1_VENDOR_ID       0x09e1
#define INT51X1_PRODUCT_ID      0x5121

#define INT51X1_HEADER_SIZE     2       /* 2 byte header */

static int int51x1_rx_fixup(struct usbnet *dev, struct sk_buff *skb)
{
        int len;

        if (!(pskb_may_pull(skb, INT51X1_HEADER_SIZE))) {
                netdev_err(dev->net, "unexpected tiny rx frame\n");
                return 0;
        }

        len = le16_to_cpu(*(__le16 *)&skb->data[skb->len - 2]);

        skb_trim(skb, len);

        return 1;
}

static struct sk_buff *int51x1_tx_fixup(struct usbnet *dev,
                struct sk_buff *skb, gfp_t flags)
{
        int pack_len = skb->len;
        int pack_with_header_len = pack_len + INT51X1_HEADER_SIZE;
        int headroom = skb_headroom(skb);
        int tailroom = skb_tailroom(skb);
        int need_tail = 0;
        __le16 *len;

        /* if packet and our header is smaller than 64 pad to 64 (+ ZLP) */
        if ((pack_with_header_len) < dev->maxpacket)
                need_tail = dev->maxpacket - pack_with_header_len + 1;
        /*
         * usbnet would send a ZLP if packetlength mod urbsize == 0 for us,
         * but we need to know ourself, because this would add to the length
         * we send down to the device...
         */
        else if (!(pack_with_header_len % dev->maxpacket))
                need_tail = 1;

        if (!skb_cloned(skb) &&
                        (headroom + tailroom >= need_tail + INT51X1_HEADER_SIZE)) {
                if (headroom < INT51X1_HEADER_SIZE || tailroom < need_tail) {
                        skb->data = memmove(skb->head + INT51X1_HEADER_SIZE,
                                        skb->data, skb->len);
                        skb_set_tail_pointer(skb, skb->len);
                }
        } else {
                struct sk_buff *skb2;

                skb2 = skb_copy_expand(skb,
                                INT51X1_HEADER_SIZE,
                                need_tail,
                                flags);
                dev_kfree_skb_any(skb);
                if (!skb2)
                        return NULL;
                skb = skb2;
        }

        pack_len += need_tail;
        pack_len &= 0x07ff;

        len = __skb_push(skb, INT51X1_HEADER_SIZE);
        *len = cpu_to_le16(pack_len);

        if(need_tail)
                __skb_put_zero(skb, need_tail);

        return skb;
}

static const struct net_device_ops int51x1_netdev_ops = {
        .ndo_open               = usbnet_open,
        .ndo_stop               = usbnet_stop,
        .ndo_start_xmit         = usbnet_start_xmit,
        .ndo_tx_timeout         = usbnet_tx_timeout,
        .ndo_change_mtu         = usbnet_change_mtu,
        .ndo_get_stats64        = dev_get_tstats64,
        .ndo_set_mac_address    = eth_mac_addr,
        .ndo_validate_addr      = eth_validate_addr,
        .ndo_set_rx_mode        = usbnet_set_rx_mode,
};

static int int51x1_bind(struct usbnet *dev, struct usb_interface *intf)
{
        int status = usbnet_get_ethernet_addr(dev, 3);

        if (status)
                return status;

        dev->net->hard_header_len += INT51X1_HEADER_SIZE;
        dev->hard_mtu = dev->net->mtu + dev->net->hard_header_len;
        dev->net->netdev_ops = &int51x1_netdev_ops;

        return usbnet_get_endpoints(dev, intf);
}

static const struct driver_info int51x1_info = {
        .description = "Intellon usb powerline adapter",
        .bind        = int51x1_bind,
        .rx_fixup    = int51x1_rx_fixup,
        .tx_fixup    = int51x1_tx_fixup,
        .set_rx_mode = usbnet_cdc_update_filter,
        .in          = 1,
        .out         = 2,
        .flags       = FLAG_ETHER,
};

static const struct usb_device_id products[] = {
        {
        USB_DEVICE(INT51X1_VENDOR_ID, INT51X1_PRODUCT_ID),
                .driver_info = (unsigned long) &int51x1_info,
        },
        {},
};
MODULE_DEVICE_TABLE(usb, products);

static struct usb_driver int51x1_driver = {
        .name       = "int51x1",
        .id_table   = products,
        .probe      = usbnet_probe,
        .disconnect = usbnet_disconnect,
        .suspend    = usbnet_suspend,
        .resume     = usbnet_resume,
        .disable_hub_initiated_lpm = 1,
};

module_usb_driver(int51x1_driver);

MODULE_AUTHOR("Peter Holik");
MODULE_DESCRIPTION("Intellon usb powerline adapter");
MODULE_LICENSE("GPL");