/*
 * Copyright (c) 2015 National Instruments
 *
 * (C) Copyright 2015
 * Joe Hershberger <joe.hershberger@ni.com>
 *
 * SPDX-License-Identifier:     GPL-2.0
 */

#include <asm/eth-raw-os.h>
#include <common.h>
#include <dm.h>
#include <malloc.h>
#include <net.h>

DECLARE_GLOBAL_DATA_PTR;

static int reply_arp;
static struct in_addr arp_ip;

static int sb_eth_raw_start(struct udevice *dev)
{
        struct eth_sandbox_raw_priv *priv = dev_get_priv(dev);
        struct eth_pdata *pdata = dev_get_platdata(dev);
        const char *interface;

        debug("eth_sandbox_raw: Start\n");

        interface = fdt_getprop(gd->fdt_blob, dev->of_offset,
                                            "host-raw-interface", NULL);
        if (interface == NULL)
                return -EINVAL;

        if (strcmp(interface, "lo") == 0) {
                priv->local = 1;
                setenv("ipaddr", "127.0.0.1");
                setenv("serverip", "127.0.0.1");
        }
        return sandbox_eth_raw_os_start(interface, pdata->enetaddr, priv);
}

static int sb_eth_raw_send(struct udevice *dev, void *packet, int length)
{
        struct eth_sandbox_raw_priv *priv = dev_get_priv(dev);

        debug("eth_sandbox_raw: Send packet %d\n", length);

        if (priv->local) {
                struct ethernet_hdr *eth = packet;

                if (ntohs(eth->et_protlen) == PROT_ARP) {
                        struct arp_hdr *arp = packet + ETHER_HDR_SIZE;

                        /**
                         * localhost works on a higher-level API in Linux than
                         * ARP packets, so fake it
                         */
                        arp_ip = net_read_ip(&arp->ar_tpa);
                        reply_arp = 1;
                        return 0;
                }
                packet += ETHER_HDR_SIZE;
                length -= ETHER_HDR_SIZE;
        }
        return sandbox_eth_raw_os_send(packet, length, priv);
}

static int sb_eth_raw_recv(struct udevice *dev, int flags, uchar **packetp)
{
        struct eth_pdata *pdata = dev_get_platdata(dev);
        struct eth_sandbox_raw_priv *priv = dev_get_priv(dev);
        int retval = 0;
        int length;

        if (reply_arp) {
                struct arp_hdr *arp = (void *)net_rx_packets[0] +
                        ETHER_HDR_SIZE;

                /*
                 * Fake an ARP response. The u-boot network stack is sending an
                 * ARP request (to find the MAC address to address the actual
                 * packet to) and requires an ARP response to continue. Since
                 * this is the localhost interface, there is no Etherent level
                 * traffic at all, so there is no way to send an ARP request or
                 * to get a response. For this reason we fake the response to
                 * make the u-boot network stack happy.
                 */
                arp->ar_hrd = htons(ARP_ETHER);
                arp->ar_pro = htons(PROT_IP);
                arp->ar_hln = ARP_HLEN;
                arp->ar_pln = ARP_PLEN;
                arp->ar_op = htons(ARPOP_REPLY);
                /* Any non-zero MAC address will work */
                memset(&arp->ar_sha, 0x01, ARP_HLEN);
                /* Use whatever IP we were looking for (always 127.0.0.1?) */
                net_write_ip(&arp->ar_spa, arp_ip);
                memcpy(&arp->ar_tha, pdata->enetaddr, ARP_HLEN);
                net_write_ip(&arp->ar_tpa, net_ip);
                length = ARP_HDR_SIZE;
        } else {
                /* If local, the Ethernet header won't be included; skip it */
                uchar *pktptr = priv->local ?
                        net_rx_packets[0] + ETHER_HDR_SIZE : net_rx_packets[0];

                retval = sandbox_eth_raw_os_recv(pktptr, &length, priv);
        }

        if (!retval && length) {
                if (priv->local) {
                        struct ethernet_hdr *eth = (void *)net_rx_packets[0];

                        /* Fill in enough of the missing Ethernet header */
                        memcpy(eth->et_dest, pdata->enetaddr, ARP_HLEN);
                        memset(eth->et_src, 0x01, ARP_HLEN);
                        eth->et_protlen = htons(reply_arp ? PROT_ARP : PROT_IP);
                        reply_arp = 0;
                        length += ETHER_HDR_SIZE;
                }

                debug("eth_sandbox_raw: received packet %d\n",
                      length);
                *packetp = net_rx_packets[0];
                return length;
        }
        return retval;
}

static void sb_eth_raw_stop(struct udevice *dev)
{
        struct eth_sandbox_raw_priv *priv = dev_get_priv(dev);

        debug("eth_sandbox_raw: Stop\n");

        sandbox_eth_raw_os_stop(priv);
}

static const struct eth_ops sb_eth_raw_ops = {
        .start                  = sb_eth_raw_start,
        .send                   = sb_eth_raw_send,
        .recv                   = sb_eth_raw_recv,
        .stop                   = sb_eth_raw_stop,
};

static int sb_eth_raw_ofdata_to_platdata(struct udevice *dev)
{
        struct eth_pdata *pdata = dev_get_platdata(dev);

        pdata->iobase = dev_get_addr(dev);
        return 0;
}

static const struct udevice_id sb_eth_raw_ids[] = {
        { .compatible = "sandbox,eth-raw" },
        { }
};

U_BOOT_DRIVER(eth_sandbox_raw) = {
        .name   = "eth_sandbox_raw",
        .id     = UCLASS_ETH,
        .of_match = sb_eth_raw_ids,
        .ofdata_to_platdata = sb_eth_raw_ofdata_to_platdata,
        .ops    = &sb_eth_raw_ops,
        .priv_auto_alloc_size = sizeof(struct eth_sandbox_raw_priv),
        .platdata_auto_alloc_size = sizeof(struct eth_pdata),
};