/*
 * Copyright (c) 2012 GCT Semiconductor, Inc. All rights reserved.
 *
 * This software is licensed under the terms of the GNU General Public
 * License version 2, as published by the Free Software Foundation, and
 * may be copied, distributed, and modified under those terms.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/etherdevice.h>
#include <linux/ip.h>
#include <linux/ipv6.h>
#include <linux/udp.h>
#include <linux/in.h>
#include <linux/if_arp.h>
#include <linux/if_ether.h>
#include <linux/if_vlan.h>
#include <linux/in6.h>
#include <linux/tcp.h>
#include <linux/icmp.h>
#include <linux/icmpv6.h>
#include <linux/uaccess.h>
#include <net/ndisc.h>

#include "gdm_lte.h"
#include "netlink_k.h"
#include "hci.h"
#include "hci_packet.h"
#include "gdm_endian.h"

/*
 * Netlink protocol number
 */
#define NETLINK_LTE 30

/*
 * Default MTU Size
 */
#define DEFAULT_MTU_SIZE 1500

#define IP_VERSION_4    4
#define IP_VERSION_6    6

static struct {
        int ref_cnt;
        struct sock *sock;
} lte_event;

static struct device_type wwan_type = {
        .name   = "wwan",
};

static int gdm_lte_open(struct net_device *dev)
{
        netif_start_queue(dev);
        return 0;
}

static int gdm_lte_close(struct net_device *dev)
{
        netif_stop_queue(dev);
        return 0;
}

static int gdm_lte_set_config(struct net_device *dev, struct ifmap *map)
{
        if (dev->flags & IFF_UP)
                return -EBUSY;
        return 0;
}

static void tx_complete(void *arg)
{
        struct nic *nic = arg;

        if (netif_queue_stopped(nic->netdev))
                netif_wake_queue(nic->netdev);
}

static int gdm_lte_rx(struct sk_buff *skb, struct nic *nic, int nic_type)
{
        int ret;

        ret = netif_rx_ni(skb);
        if (ret == NET_RX_DROP) {
                nic->stats.rx_dropped++;
        } else {
                nic->stats.rx_packets++;
                nic->stats.rx_bytes += skb->len + ETH_HLEN;
        }

        return 0;
}

static int gdm_lte_emulate_arp(struct sk_buff *skb_in, u32 nic_type)
{
        struct nic *nic = netdev_priv(skb_in->dev);
        struct sk_buff *skb_out;
        struct ethhdr eth;
        struct vlan_ethhdr vlan_eth;
        struct arphdr *arp_in;
        struct arphdr *arp_out;
        struct arpdata {
                u8 ar_sha[ETH_ALEN];
                u8 ar_sip[4];
                u8 ar_tha[ETH_ALEN];
                u8 ar_tip[4];
        };
        struct arpdata *arp_data_in;
        struct arpdata *arp_data_out;
        u8 arp_temp[60];
        void *mac_header_data;
        u32 mac_header_len;

        /* Format the mac header so that it can be put to skb */
        if (ntohs(((struct ethhdr *)skb_in->data)->h_proto) == ETH_P_8021Q) {
                memcpy(&vlan_eth, skb_in->data, sizeof(struct vlan_ethhdr));
                mac_header_data = &vlan_eth;
                mac_header_len = VLAN_ETH_HLEN;
        } else {
                memcpy(&eth, skb_in->data, sizeof(struct ethhdr));
                mac_header_data = &eth;
                mac_header_len = ETH_HLEN;
        }

        /* Get the pointer of the original request */
        arp_in = (struct arphdr *)(skb_in->data + mac_header_len);
        arp_data_in = (struct arpdata *)(skb_in->data + mac_header_len +
                                        sizeof(struct arphdr));

        /* Get the pointer of the outgoing response */
        arp_out = (struct arphdr *)arp_temp;
        arp_data_out = (struct arpdata *)(arp_temp + sizeof(struct arphdr));

        /* Copy the arp header */
        memcpy(arp_out, arp_in, sizeof(struct arphdr));
        arp_out->ar_op = htons(ARPOP_REPLY);

        /* Copy the arp payload: based on 2 bytes of mac and fill the IP */
        arp_data_out->ar_sha[0] = arp_data_in->ar_sha[0];
        arp_data_out->ar_sha[1] = arp_data_in->ar_sha[1];
        memcpy(&arp_data_out->ar_sha[2], &arp_data_in->ar_tip[0], 4);
        memcpy(&arp_data_out->ar_sip[0], &arp_data_in->ar_tip[0], 4);
        memcpy(&arp_data_out->ar_tha[0], &arp_data_in->ar_sha[0], 6);
        memcpy(&arp_data_out->ar_tip[0], &arp_data_in->ar_sip[0], 4);

        /* Fill the destination mac with source mac of the received packet */
        memcpy(mac_header_data, mac_header_data + ETH_ALEN, ETH_ALEN);
        /* Fill the source mac with nic's source mac */
        memcpy(mac_header_data + ETH_ALEN, nic->src_mac_addr, ETH_ALEN);

        /* Alloc skb and reserve align */
        skb_out = dev_alloc_skb(skb_in->len);
        if (!skb_out)
                return -ENOMEM;
        skb_reserve(skb_out, NET_IP_ALIGN);

        memcpy(skb_put(skb_out, mac_header_len), mac_header_data,
               mac_header_len);
        memcpy(skb_put(skb_out, sizeof(struct arphdr)), arp_out,
               sizeof(struct arphdr));
        memcpy(skb_put(skb_out, sizeof(struct arpdata)), arp_data_out,
               sizeof(struct arpdata));

        skb_out->protocol = ((struct ethhdr *)mac_header_data)->h_proto;
        skb_out->dev = skb_in->dev;
        skb_reset_mac_header(skb_out);
        skb_pull(skb_out, ETH_HLEN);

        gdm_lte_rx(skb_out, nic, nic_type);

        return 0;
}

static int icmp6_checksum(struct ipv6hdr *ipv6, u16 *ptr, int len)
{
        unsigned short *w = ptr;
        int sum = 0;
        int i;

        union {
                struct {
                        u8 ph_src[16];
                        u8 ph_dst[16];
                        u32 ph_len;
                        u8 ph_zero[3];
                        u8 ph_nxt;
                } ph __packed;
                u16 pa[20];
        } pseudo_header;

        memset(&pseudo_header, 0, sizeof(pseudo_header));
        memcpy(&pseudo_header.ph.ph_src, &ipv6->saddr.in6_u.u6_addr8, 16);
        memcpy(&pseudo_header.ph.ph_dst, &ipv6->daddr.in6_u.u6_addr8, 16);
        pseudo_header.ph.ph_len = ipv6->payload_len;
        pseudo_header.ph.ph_nxt = ipv6->nexthdr;

        w = (u16 *)&pseudo_header;
        for (i = 0; i < ARRAY_SIZE(pseudo_header.pa); i++)
                sum += pseudo_header.pa[i];

        w = ptr;
        while (len > 1) {
                sum += *w++;
                len -= 2;
        }

        sum = (sum >> 16) + (sum & 0xFFFF);
        sum += (sum >> 16);
        sum = ~sum & 0xffff;

        return sum;
}

static int gdm_lte_emulate_ndp(struct sk_buff *skb_in, u32 nic_type)
{
        struct nic *nic = netdev_priv(skb_in->dev);
        struct sk_buff *skb_out;
        struct ethhdr eth;
        struct vlan_ethhdr vlan_eth;
        struct neighbour_advertisement {
                u8 target_address[16];
                u8 type;
                u8 length;
                u8 link_layer_address[6];
        };
        struct neighbour_advertisement na;
        struct neighbour_solicitation {
                u8 target_address[16];
        };
        struct neighbour_solicitation *ns;
        struct ipv6hdr *ipv6_in;
        struct ipv6hdr ipv6_out;
        struct icmp6hdr *icmp6_in;
        struct icmp6hdr icmp6_out;

        void *mac_header_data;
        u32 mac_header_len;

        /* Format the mac header so that it can be put to skb */
        if (ntohs(((struct ethhdr *)skb_in->data)->h_proto) == ETH_P_8021Q) {
                memcpy(&vlan_eth, skb_in->data, sizeof(struct vlan_ethhdr));
                if (ntohs(vlan_eth.h_vlan_encapsulated_proto) != ETH_P_IPV6)
                        return -1;
                mac_header_data = &vlan_eth;
                mac_header_len = VLAN_ETH_HLEN;
        } else {
                memcpy(&eth, skb_in->data, sizeof(struct ethhdr));
                if (ntohs(eth.h_proto) != ETH_P_IPV6)
                        return -1;
                mac_header_data = &eth;
                mac_header_len = ETH_HLEN;
        }

        /* Check if this is IPv6 ICMP packet */
        ipv6_in = (struct ipv6hdr *)(skb_in->data + mac_header_len);
        if (ipv6_in->version != 6 || ipv6_in->nexthdr != IPPROTO_ICMPV6)
                return -1;

        /* Check if this is NDP packet */
        icmp6_in = (struct icmp6hdr *)(skb_in->data + mac_header_len +
                                        sizeof(struct ipv6hdr));
        if (icmp6_in->icmp6_type == NDISC_ROUTER_SOLICITATION) { /* Check RS */
                return -1;
        } else if (icmp6_in->icmp6_type == NDISC_NEIGHBOUR_SOLICITATION) {
                /* Check NS */
                u8 icmp_na[sizeof(struct icmp6hdr) +
                        sizeof(struct neighbour_advertisement)];
                u8 zero_addr8[16] = {0,};

                if (memcmp(ipv6_in->saddr.in6_u.u6_addr8, zero_addr8, 16) == 0)
                        /* Duplicate Address Detection: Source IP is all zero */
                        return 0;

                icmp6_out.icmp6_type = NDISC_NEIGHBOUR_ADVERTISEMENT;
                icmp6_out.icmp6_code = 0;
                icmp6_out.icmp6_cksum = 0;
                /* R=0, S=1, O=1 */
                icmp6_out.icmp6_dataun.un_data32[0] = htonl(0x60000000);

                ns = (struct neighbour_solicitation *)
                        (skb_in->data + mac_header_len +
                         sizeof(struct ipv6hdr) + sizeof(struct icmp6hdr));
                memcpy(&na.target_address, ns->target_address, 16);
                na.type = 0x02;
                na.length = 1;
                na.link_layer_address[0] = 0x00;
                na.link_layer_address[1] = 0x0a;
                na.link_layer_address[2] = 0x3b;
                na.link_layer_address[3] = 0xaf;
                na.link_layer_address[4] = 0x63;
                na.link_layer_address[5] = 0xc7;

                memcpy(&ipv6_out, ipv6_in, sizeof(struct ipv6hdr));
                memcpy(ipv6_out.saddr.in6_u.u6_addr8, &na.target_address, 16);
                memcpy(ipv6_out.daddr.in6_u.u6_addr8,
                       ipv6_in->saddr.in6_u.u6_addr8, 16);
                ipv6_out.payload_len = htons(sizeof(struct icmp6hdr) +
                                sizeof(struct neighbour_advertisement));

                memcpy(icmp_na, &icmp6_out, sizeof(struct icmp6hdr));
                memcpy(icmp_na + sizeof(struct icmp6hdr), &na,
                       sizeof(struct neighbour_advertisement));

                icmp6_out.icmp6_cksum = icmp6_checksum(&ipv6_out,
                                        (u16 *)icmp_na, sizeof(icmp_na));
        } else {
                return -1;
        }

        /* Fill the destination mac with source mac of the received packet */
        memcpy(mac_header_data, mac_header_data + ETH_ALEN, ETH_ALEN);
        /* Fill the source mac with nic's source mac */
        memcpy(mac_header_data + ETH_ALEN, nic->src_mac_addr, ETH_ALEN);

        /* Alloc skb and reserve align */
        skb_out = dev_alloc_skb(skb_in->len);
        if (!skb_out)
                return -ENOMEM;
        skb_reserve(skb_out, NET_IP_ALIGN);

        memcpy(skb_put(skb_out, mac_header_len), mac_header_data,
               mac_header_len);
        memcpy(skb_put(skb_out, sizeof(struct ipv6hdr)), &ipv6_out,
               sizeof(struct ipv6hdr));
        memcpy(skb_put(skb_out, sizeof(struct icmp6hdr)), &icmp6_out,
               sizeof(struct icmp6hdr));
        memcpy(skb_put(skb_out, sizeof(struct neighbour_advertisement)), &na,
               sizeof(struct neighbour_advertisement));

        skb_out->protocol = ((struct ethhdr *)mac_header_data)->h_proto;
        skb_out->dev = skb_in->dev;
        skb_reset_mac_header(skb_out);
        skb_pull(skb_out, ETH_HLEN);

        gdm_lte_rx(skb_out, nic, nic_type);

        return 0;
}

static s32 gdm_lte_tx_nic_type(struct net_device *dev, struct sk_buff *skb)
{
        struct nic *nic = netdev_priv(dev);
        struct ethhdr *eth;
        struct vlan_ethhdr *vlan_eth;
        struct iphdr *ip;
        struct ipv6hdr *ipv6;
        int mac_proto;
        void *network_data;
        u32 nic_type = 0;

        /* NIC TYPE is based on the nic_id of this net_device */
        nic_type = 0x00000010 | nic->nic_id;

        /* Get ethernet protocol */
        eth = (struct ethhdr *)skb->data;
        if (ntohs(eth->h_proto) == ETH_P_8021Q) {
                vlan_eth = (struct vlan_ethhdr *)skb->data;
                mac_proto = ntohs(vlan_eth->h_vlan_encapsulated_proto);
                network_data = skb->data + VLAN_ETH_HLEN;
                nic_type |= NIC_TYPE_F_VLAN;
        } else {
                mac_proto = ntohs(eth->h_proto);
                network_data = skb->data + ETH_HLEN;
        }

        /* Process packet for nic type */
        switch (mac_proto) {
        case ETH_P_ARP:
                nic_type |= NIC_TYPE_ARP;
                break;
        case ETH_P_IP:
                nic_type |= NIC_TYPE_F_IPV4;
                ip = network_data;

                /* Check DHCPv4 */
                if (ip->protocol == IPPROTO_UDP) {
                        struct udphdr *udp =
                                        network_data + sizeof(struct iphdr);
                        if (ntohs(udp->dest) == 67 || ntohs(udp->dest) == 68)
                                nic_type |= NIC_TYPE_F_DHCP;
                }
                break;
        case ETH_P_IPV6:
                nic_type |= NIC_TYPE_F_IPV6;
                ipv6 = network_data;

                if (ipv6->nexthdr == IPPROTO_ICMPV6) /* Check NDP request */ {
                        struct icmp6hdr *icmp6 =
                                        network_data + sizeof(struct ipv6hdr);
                        if (icmp6->icmp6_type == NDISC_NEIGHBOUR_SOLICITATION)
                                nic_type |= NIC_TYPE_ICMPV6;
                } else if (ipv6->nexthdr == IPPROTO_UDP) /* Check DHCPv6 */ {
                        struct udphdr *udp =
                                        network_data + sizeof(struct ipv6hdr);
                        if (ntohs(udp->dest) == 546 || ntohs(udp->dest) == 547)
                                nic_type |= NIC_TYPE_F_DHCP;
                }
                break;
        default:
                break;
        }

        return nic_type;
}

static int gdm_lte_tx(struct sk_buff *skb, struct net_device *dev)
{
        struct nic *nic = netdev_priv(dev);
        u32 nic_type;
        void *data_buf;
        int data_len;
        int idx;
        int ret = 0;

        nic_type = gdm_lte_tx_nic_type(dev, skb);
        if (nic_type == 0) {
                netdev_err(dev, "tx - invalid nic_type\n");
                return -1;
        }

        if (nic_type & NIC_TYPE_ARP) {
                if (gdm_lte_emulate_arp(skb, nic_type) == 0) {
                        dev_kfree_skb(skb);
                        return 0;
                }
        }

        if (nic_type & NIC_TYPE_ICMPV6) {
                if (gdm_lte_emulate_ndp(skb, nic_type) == 0) {
                        dev_kfree_skb(skb);
                        return 0;
                }
        }

        /*
         * Need byte shift (that is, remove VLAN tag) if there is one
         * For the case of ARP, this breaks the offset as vlan_ethhdr+4
         * is treated as ethhdr However, it shouldn't be a problem as
         * the response starts from arp_hdr and ethhdr is created by this
         * driver based on the NIC mac
         */
        if (nic_type & NIC_TYPE_F_VLAN) {
                struct vlan_ethhdr *vlan_eth = (struct vlan_ethhdr *)skb->data;

                nic->vlan_id = ntohs(vlan_eth->h_vlan_TCI) & VLAN_VID_MASK;
                data_buf = skb->data + (VLAN_ETH_HLEN - ETH_HLEN);
                data_len = skb->len - (VLAN_ETH_HLEN - ETH_HLEN);
        } else {
                nic->vlan_id = 0;
                data_buf = skb->data;
                data_len = skb->len;
        }

        /* If it is a ICMPV6 packet, clear all the other bits :
         * for backward compatibility with the firmware
         */
        if (nic_type & NIC_TYPE_ICMPV6)
                nic_type = NIC_TYPE_ICMPV6;

        /* If it is not a dhcp packet, clear all the flag bits :
         * original NIC, otherwise the special flag (IPVX | DHCP)
         */
        if (!(nic_type & NIC_TYPE_F_DHCP))
                nic_type &= NIC_TYPE_MASK;

        ret = sscanf(dev->name, "lte%d", &idx);
        if (ret != 1) {
                dev_kfree_skb(skb);
                return -EINVAL;
        }

        ret = nic->phy_dev->send_sdu_func(nic->phy_dev->priv_dev,
                                          data_buf, data_len,
                                          nic->pdn_table.dft_eps_id, 0,
                                          tx_complete, nic, idx,
                                          nic_type);

        if (ret == TX_NO_BUFFER || ret == TX_NO_SPC) {
                netif_stop_queue(dev);
                if (ret == TX_NO_BUFFER)
                        ret = 0;
                else
                        ret = -ENOSPC;
        } else if (ret == TX_NO_DEV) {
                ret = -ENODEV;
        }

        /* Updates tx stats */
        if (ret) {
                nic->stats.tx_dropped++;
        } else {
                nic->stats.tx_packets++;
                nic->stats.tx_bytes += data_len;
        }
        dev_kfree_skb(skb);

        return 0;
}

static struct net_device_stats *gdm_lte_stats(struct net_device *dev)
{
        struct nic *nic = netdev_priv(dev);

        return &nic->stats;
}

static int gdm_lte_event_send(struct net_device *dev, char *buf, int len)
{
        struct nic *nic = netdev_priv(dev);
        struct hci_packet *hci = (struct hci_packet *)buf;
        int idx;
        int ret;

        ret = sscanf(dev->name, "lte%d", &idx);
        if (ret != 1)
                return -EINVAL;

        return netlink_send(lte_event.sock, idx, 0, buf,
                            gdm_dev16_to_cpu(
                                    nic->phy_dev->get_endian(
                                            nic->phy_dev->priv_dev), hci->len)
                            + HCI_HEADER_SIZE);
}

static void gdm_lte_event_rcv(struct net_device *dev, u16 type,
                              void *msg, int len)
{
        struct nic *nic = netdev_priv(dev);

        nic->phy_dev->send_hci_func(nic->phy_dev->priv_dev, msg, len, NULL,
                                    NULL);
}

int gdm_lte_event_init(void)
{
        if (lte_event.ref_cnt == 0)
                lte_event.sock = netlink_init(NETLINK_LTE, gdm_lte_event_rcv);

        if (lte_event.sock) {
                lte_event.ref_cnt++;
                return 0;
        }

        pr_err("event init failed\n");
        return -1;
}

void gdm_lte_event_exit(void)
{
        if (lte_event.sock && --lte_event.ref_cnt == 0) {
                sock_release(lte_event.sock->sk_socket);
                lte_event.sock = NULL;
        }
}

static u8 find_dev_index(u32 nic_type)
{
        u8 index;

        index = (u8)(nic_type & 0x0000000f);
        if (index > MAX_NIC_TYPE)
                index = 0;

        return index;
}

static void gdm_lte_netif_rx(struct net_device *dev, char *buf,
                             int len, int flagged_nic_type)
{
        u32 nic_type;
        struct nic *nic;
        struct sk_buff *skb;
        struct ethhdr eth;
        struct vlan_ethhdr vlan_eth;
        void *mac_header_data;
        u32 mac_header_len;
        char ip_version = 0;

        nic_type = flagged_nic_type & NIC_TYPE_MASK;
        nic = netdev_priv(dev);

        if (flagged_nic_type & NIC_TYPE_F_DHCP) {
                /* Change the destination mac address
                 * with the one requested the IP
                 */
                if (flagged_nic_type & NIC_TYPE_F_IPV4) {
                        struct dhcp_packet {
                                u8 op;      /* BOOTREQUEST or BOOTREPLY */
                                u8 htype;   /* hardware address type.
                                             * 1 = 10mb ethernet
                                             */
                                u8 hlen;    /* hardware address length */
                                u8 hops;    /* used by relay agents only */
                                u32 xid;    /* unique id */
                                u16 secs;   /* elapsed since client began
                                             * acquisition/renewal
                                             */
                                u16 flags;  /* only one flag so far: */
                                #define BROADCAST_FLAG 0x8000
                                /* "I need broadcast replies" */
                                u32 ciaddr; /* client IP (if client is in
                                             * BOUND, RENEW or REBINDING state)
                                             */
                                u32 yiaddr; /* 'your' (client) IP address */
                                /* IP address of next server to use in
                                 * bootstrap, returned in DHCPOFFER,
                                 * DHCPACK by server
                                 */
                                u32 siaddr_nip;
                                u32 gateway_nip; /* relay agent IP address */
                                u8 chaddr[16];   /* link-layer client hardware
                                                  * address (MAC)
                                                  */
                                u8 sname[64];    /* server host name (ASCIZ) */
                                u8 file[128];    /* boot file name (ASCIZ) */
                                u32 cookie;      /* fixed first four option
                                                  * bytes (99,130,83,99 dec)
                                                  */
                        } __packed;
                        void *addr = buf + sizeof(struct iphdr) +
                                sizeof(struct udphdr) +
                                offsetof(struct dhcp_packet, chaddr);
                        ether_addr_copy(nic->dest_mac_addr, addr);
                }
        }

        if (nic->vlan_id > 0) {
                mac_header_data = (void *)&vlan_eth;
                mac_header_len = VLAN_ETH_HLEN;
        } else {
                mac_header_data = (void *)&eth;
                mac_header_len = ETH_HLEN;
        }

        /* Format the data so that it can be put to skb */
        ether_addr_copy(mac_header_data, nic->dest_mac_addr);
        memcpy(mac_header_data + ETH_ALEN, nic->src_mac_addr, ETH_ALEN);

        vlan_eth.h_vlan_TCI = htons(nic->vlan_id);
        vlan_eth.h_vlan_proto = htons(ETH_P_8021Q);

        if (nic_type == NIC_TYPE_ARP) {
                /* Should be response: Only happens because
                 * there was a request from the host
                 */
                eth.h_proto = htons(ETH_P_ARP);
                vlan_eth.h_vlan_encapsulated_proto = htons(ETH_P_ARP);
        } else {
                ip_version = buf[0] >> 4;
                if (ip_version == IP_VERSION_4) {
                        eth.h_proto = htons(ETH_P_IP);
                        vlan_eth.h_vlan_encapsulated_proto = htons(ETH_P_IP);
                } else if (ip_version == IP_VERSION_6) {
                        eth.h_proto = htons(ETH_P_IPV6);
                        vlan_eth.h_vlan_encapsulated_proto = htons(ETH_P_IPV6);
                } else {
                        netdev_err(dev, "Unknown IP version %d\n", ip_version);
                        return;
                }
        }

        /* Alloc skb and reserve align */
        skb = dev_alloc_skb(len + mac_header_len + NET_IP_ALIGN);
        if (!skb)
                return;
        skb_reserve(skb, NET_IP_ALIGN);

        memcpy(skb_put(skb, mac_header_len), mac_header_data, mac_header_len);
        memcpy(skb_put(skb, len), buf, len);

        skb->protocol = ((struct ethhdr *)mac_header_data)->h_proto;
        skb->dev = dev;
        skb_reset_mac_header(skb);
        skb_pull(skb, ETH_HLEN);

        gdm_lte_rx(skb, nic, nic_type);
}

static void gdm_lte_multi_sdu_pkt(struct phy_dev *phy_dev, char *buf, int len)
{
        struct net_device *dev;
        struct multi_sdu *multi_sdu = (struct multi_sdu *)buf;
        struct sdu *sdu = NULL;
        u8 *data = (u8 *)multi_sdu->data;
        u16 i = 0;
        u16 num_packet;
        u16 hci_len;
        u16 cmd_evt;
        u32 nic_type;
        u8 index;

        hci_len = gdm_dev16_to_cpu(phy_dev->get_endian(phy_dev->priv_dev),
                                   multi_sdu->len);
        num_packet = gdm_dev16_to_cpu(phy_dev->get_endian(phy_dev->priv_dev),
                                      multi_sdu->num_packet);

        for (i = 0; i < num_packet; i++) {
                sdu = (struct sdu *)data;

                cmd_evt = gdm_dev16_to_cpu(phy_dev->
                                get_endian(phy_dev->priv_dev), sdu->cmd_evt);
                hci_len = gdm_dev16_to_cpu(phy_dev->
                                get_endian(phy_dev->priv_dev), sdu->len);
                nic_type = gdm_dev32_to_cpu(phy_dev->
                                get_endian(phy_dev->priv_dev), sdu->nic_type);

                if (cmd_evt != LTE_RX_SDU) {
                        pr_err("rx sdu wrong hci %04x\n", cmd_evt);
                        return;
                }
                if (hci_len < 12) {
                        pr_err("rx sdu invalid len %d\n", hci_len);
                        return;
                }

                index = find_dev_index(nic_type);
                if (index < MAX_NIC_TYPE) {
                        dev = phy_dev->dev[index];
                        gdm_lte_netif_rx(dev, (char *)sdu->data,
                                         (int)(hci_len - 12), nic_type);
                } else {
                        pr_err("rx sdu invalid nic_type :%x\n", nic_type);
                }

                data += ((hci_len + 3) & 0xfffc) + HCI_HEADER_SIZE;
        }
}

static void gdm_lte_pdn_table(struct net_device *dev, char *buf, int len)
{
        struct nic *nic = netdev_priv(dev);
        struct hci_pdn_table_ind *pdn_table = (struct hci_pdn_table_ind *)buf;

        if (pdn_table->activate) {
                nic->pdn_table.activate = pdn_table->activate;
                nic->pdn_table.dft_eps_id = gdm_dev32_to_cpu(
                                                nic->phy_dev->get_endian(
                                                        nic->phy_dev->priv_dev),
                                                pdn_table->dft_eps_id);
                nic->pdn_table.nic_type = gdm_dev32_to_cpu(
                                                nic->phy_dev->get_endian(
                                                        nic->phy_dev->priv_dev),
                                                pdn_table->nic_type);

                netdev_info(dev, "pdn activated, nic_type=0x%x\n",
                            nic->pdn_table.nic_type);
        } else {
                memset(&nic->pdn_table, 0x00, sizeof(struct pdn_table));
                netdev_info(dev, "pdn deactivated\n");
        }
}

static int gdm_lte_receive_pkt(struct phy_dev *phy_dev, char *buf, int len)
{
        struct hci_packet *hci = (struct hci_packet *)buf;
        struct hci_pdn_table_ind *pdn_table = (struct hci_pdn_table_ind *)buf;
        struct sdu *sdu;
        struct net_device *dev;
        int ret = 0;
        u16 cmd_evt;
        u32 nic_type;
        u8 index;

        if (!len)
                return ret;

        cmd_evt = gdm_dev16_to_cpu(phy_dev->get_endian(phy_dev->priv_dev),
                                   hci->cmd_evt);

        dev = phy_dev->dev[0];
        if (!dev)
                return 0;

        switch (cmd_evt) {
        case LTE_RX_SDU:
                sdu = (struct sdu *)hci->data;
                nic_type = gdm_dev32_to_cpu(phy_dev->
                                get_endian(phy_dev->priv_dev), sdu->nic_type);
                index = find_dev_index(nic_type);
                dev = phy_dev->dev[index];
                gdm_lte_netif_rx(dev, hci->data, len, nic_type);
                break;
        case LTE_RX_MULTI_SDU:
                gdm_lte_multi_sdu_pkt(phy_dev, buf, len);
                break;
        case LTE_LINK_ON_OFF_INDICATION:
                netdev_info(dev, "link %s\n",
                            ((struct hci_connect_ind *)buf)->connect
                            ? "on" : "off");
                break;
        case LTE_PDN_TABLE_IND:
                pdn_table = (struct hci_pdn_table_ind *)buf;
                nic_type = gdm_dev32_to_cpu(phy_dev->
                                get_endian(phy_dev->priv_dev),
                                pdn_table->nic_type);
                index = find_dev_index(nic_type);
                dev = phy_dev->dev[index];
                gdm_lte_pdn_table(dev, buf, len);
                /* Fall through */
        default:
                ret = gdm_lte_event_send(dev, buf, len);
                break;
        }

        return ret;
}

static int rx_complete(void *arg, void *data, int len, int context)
{
        struct phy_dev *phy_dev = arg;

        return gdm_lte_receive_pkt(phy_dev, data, len);
}

void start_rx_proc(struct phy_dev *phy_dev)
{
        int i;

        for (i = 0; i < MAX_RX_SUBMIT_COUNT; i++)
                phy_dev->rcv_func(phy_dev->priv_dev,
                                rx_complete, phy_dev, USB_COMPLETE);
}

static const struct net_device_ops gdm_netdev_ops = {
        .ndo_open                       = gdm_lte_open,
        .ndo_stop                       = gdm_lte_close,
        .ndo_set_config                 = gdm_lte_set_config,
        .ndo_start_xmit                 = gdm_lte_tx,
        .ndo_get_stats                  = gdm_lte_stats,
};

static u8 gdm_lte_macaddr[ETH_ALEN] = {0x00, 0x0a, 0x3b, 0x00, 0x00, 0x00};

static void form_mac_address(u8 *dev_addr, u8 *nic_src, u8 *nic_dest,
                             u8 *mac_address, u8 index)
{
        /* Form the dev_addr */
        if (!mac_address)
                ether_addr_copy(dev_addr, gdm_lte_macaddr);
        else
                ether_addr_copy(dev_addr, mac_address);

        /* The last byte of the mac address
         * should be less than or equal to 0xFC
         */
        dev_addr[ETH_ALEN - 1] += index;

        /* Create random nic src and copy the first
         * 3 bytes to be the same as dev_addr
         */
        eth_random_addr(nic_src);
        memcpy(nic_src, dev_addr, 3);

        /* Copy the nic_dest from dev_addr*/
        ether_addr_copy(nic_dest, dev_addr);
}

static void validate_mac_address(u8 *mac_address)
{
        /* if zero address or multicast bit set, restore the default value */
        if (is_zero_ether_addr(mac_address) || (mac_address[0] & 0x01)) {
                pr_err("MAC invalid, restoring default\n");
                memcpy(mac_address, gdm_lte_macaddr, 6);
        }
}

int register_lte_device(struct phy_dev *phy_dev,
                        struct device *dev, u8 *mac_address)
{
        struct nic *nic;
        struct net_device *net;
        char pdn_dev_name[16];
        int ret = 0;
        u8 index;

        validate_mac_address(mac_address);

        for (index = 0; index < MAX_NIC_TYPE; index++) {
                /* Create device name lteXpdnX */
                sprintf(pdn_dev_name, "lte%%dpdn%d", index);

                /* Allocate netdev */
                net = alloc_netdev(sizeof(struct nic), pdn_dev_name,
                                   NET_NAME_UNKNOWN, ether_setup);
                if (!net) {
                        pr_err("alloc_netdev failed\n");
                        ret = -ENOMEM;
                        goto err;
                }
                net->netdev_ops = &gdm_netdev_ops;
                net->flags &= ~IFF_MULTICAST;
                net->mtu = DEFAULT_MTU_SIZE;

                nic = netdev_priv(net);
                memset(nic, 0, sizeof(struct nic));
                nic->netdev = net;
                nic->phy_dev = phy_dev;
                nic->nic_id = index;

                form_mac_address(
                                net->dev_addr,
                                nic->src_mac_addr,
                                nic->dest_mac_addr,
                                mac_address,
                                index);

                SET_NETDEV_DEV(net, dev);
                SET_NETDEV_DEVTYPE(net, &wwan_type);

                ret = register_netdev(net);
                if (ret)
                        goto err;

                netif_carrier_on(net);

                phy_dev->dev[index] = net;
        }

        return 0;

err:
        unregister_lte_device(phy_dev);

        return ret;
}

void unregister_lte_device(struct phy_dev *phy_dev)
{
        struct net_device *net;
        int index;

        for (index = 0; index < MAX_NIC_TYPE; index++) {
                net = phy_dev->dev[index];
                if (!net)
                        continue;

                unregister_netdev(net);
                free_netdev(net);
        }
}