#include <linux/version.h>
#include <linux/module.h>
#include <linux/completion.h>
#include <linux/usb.h>
#if LINUX_VERSION_CODE > KERNEL_VERSION(3,0,0)
#include <linux/atomic.h>
#else
#include <asm/atomic.h>
#endif
#include <linux/slab.h>
#include <linux/netdevice.h>

#include "../hgic_def.h"
#include "utils.h"

#define HGIC_PKT_MAX_LEN 2048
#define HGIC_TX_URB_CNT 64
#define HGIC_RX_URB_CNT 64

#define HGIC_USB_STATUS_STOP    BIT(0)
#define HGIC_USB_STATUS_ERR     BIT(1)

#define HGIC_USB_BUF_FLAG_USED 0x00000001
#define USB_TX_HEADROM 4

struct hgic_usb_buf {
    struct list_head  list;
    struct hgic_usb *usbdev;
    struct urb       *urb;
    struct sk_buff   *skb;
    int    flag;
};

struct hgic_usb {
    struct usb_device *udev;
    uint   ep_in, ep_out;
    uint   ep_out_size, ep_in_size;
    uint   status;
    struct list_head  tx_freeq;
    struct list_head  rx_freeq;
    struct list_head  used;
    struct semaphore  tx_sema;
    spinlock_t qlock;
    struct hgic_bus bus;
};

static int txq_cnt = HGIC_TX_URB_CNT;
static int rxq_cnt = HGIC_RX_URB_CNT;

static const struct usb_device_id hgic_usb_wdev_ids[] = {
    { USB_DEVICE(HGIC_VENDOR_ID, HGIC_WLAN_AH_4001) },
    { USB_DEVICE(HGIC_VENDOR_ID, HGIC_WLAN_AH_4002) },
    { USB_DEVICE(HGIC_VENDOR_ID, HGIC_WLAN_AH_4102) },
    { /* end: all zeroes */             },
};
MODULE_DEVICE_TABLE(usb, hgic_usb_wdev_ids);
static void hgic_usb_receive(struct urb *urb);

static void hgic_usb_free(struct hgic_usb *usbdev)
{
    unsigned long flags;
    struct hgic_usb_buf *buf, *n;

    spin_lock_irqsave(&usbdev->qlock, flags);
    list_for_each_entry_safe(buf, n, &usbdev->tx_freeq, list) {
        list_del(&buf->list);
        usb_free_urb(buf->urb);
        kfree(buf);
        //hgic_dbg("free usb tx buff\r\n");
    }
    list_for_each_entry_safe(buf, n, &usbdev->rx_freeq, list) {
        list_del(&buf->list);
        usb_free_urb(buf->urb);
        kfree(buf);
        //hgic_dbg("free usb rx buff\r\n");
    }
    list_for_each_entry_safe(buf, n, &usbdev->used, list) {
        usb_kill_urb(buf->urb);
        list_del(&buf->list);
        usb_free_urb(buf->urb);
        kfree(buf);
    }
    spin_unlock_irqrestore(&usbdev->qlock, flags);
}

static int hgic_usb_qinit(struct hgic_usb *usb, struct list_head *q, int qsize)
{
    int i = 0;
    struct hgic_usb_buf *buf = NULL;

    for (i = 0; i < qsize; i++) {
        buf = kzalloc(sizeof(struct hgic_usb_buf), GFP_ATOMIC);
        if (buf == NULL) {
            break;
        }

        buf->usbdev = usb;
        buf->urb = usb_alloc_urb(0, GFP_KERNEL);
        if (buf->urb) {
            list_add_tail(&buf->list, q);
        } else {
            kfree(buf);
            break;
        }
    }
    return i;
}

struct hgic_usb_buf *hgic_usb_deq(struct hgic_usb *usbdev, struct list_head *q)
{
    struct hgic_usb_buf *buf = NULL;
    unsigned long flags;

    spin_lock_irqsave(&usbdev->qlock, flags);
    if (!list_empty(q)) {
        buf = list_first_entry(q, struct hgic_usb_buf, list);
        buf->flag |= HGIC_USB_BUF_FLAG_USED;
        list_del(&buf->list);
        list_add_tail(&buf->list, &usbdev->used);
    }
    spin_unlock_irqrestore(&usbdev->qlock, flags);
    return buf;
}

void hgic_usb_enq(struct hgic_usb_buf *buf, struct list_head *q)
{
    unsigned long flags;

    spin_lock_irqsave(&buf->usbdev->qlock, flags);
    buf->skb = NULL;
    buf->flag &= ~HGIC_USB_BUF_FLAG_USED;
    list_del(&buf->list);
    list_add_tail(&buf->list, q);
    spin_unlock_irqrestore(&buf->usbdev->qlock, flags);
}

static int hgic_usb_submit_rx_urb(struct hgic_usb_buf *buf)
{
    int ret = -1;

    buf->skb = dev_alloc_skb(HGIC_PKT_MAX_LEN);
    if (!buf->skb) {
        hgic_err("alloc skb failed\r\n");
        hgic_usb_enq(buf, &buf->usbdev->rx_freeq);
        return -1;
    }
    usb_fill_bulk_urb(buf->urb, buf->usbdev->udev,
                      usb_rcvbulkpipe(buf->usbdev->udev, buf->usbdev->ep_in),
                      buf->skb->data, HGIC_PKT_MAX_LEN, hgic_usb_receive, buf);
    ret = usb_submit_urb(buf->urb, GFP_ATOMIC);
    if (ret) {
        hgic_err("submit rx urb failed: %d\n", ret);
        dev_kfree_skb_any(buf->skb);
        hgic_usb_enq(buf, &buf->usbdev->rx_freeq);
        buf->usbdev->status |= HGIC_USB_STATUS_ERR;
        return -1;
    }
    return 0;
}

static int hgic_usb_submit_rx_urbs(struct hgic_usb *usbdev)
{
    int ret = 0;
    struct hgic_usb_buf *buf = NULL;

    while ((buf = hgic_usb_deq(usbdev, &usbdev->rx_freeq))) {
        ret = hgic_usb_submit_rx_urb(buf);
        if (ret) {
            break;
        }
    }
    return ret;
}

static void hgic_usb_receive(struct urb *urb)
{
    struct hgic_usb_buf *buf = (struct hgic_usb_buf *)urb->context;

    if (buf->usbdev->status & (HGIC_USB_STATUS_STOP | HGIC_USB_STATUS_ERR)) {
        dev_kfree_skb_any(buf->skb);
        hgic_usb_enq(buf, &buf->usbdev->rx_freeq);
        return;
    }

    if (urb->actual_length > 0) {
        buf->usbdev->bus.rx_packet(buf->usbdev->bus.bus_priv, buf->skb, urb->actual_length);
    } else {
        dev_kfree_skb_any(buf->skb);
    }
    hgic_usb_submit_rx_urb(buf);
}

static void hgic_usb_tx_complete(struct urb *urb)
{
    struct hgic_usb_buf *buf = (struct hgic_usb_buf *)urb->context;
    //hgic_skip_padding(buf->skb);
    buf->usbdev->bus.tx_complete(buf->usbdev->bus.bus_priv, buf->skb, !urb->status);
    hgic_usb_enq(buf, &buf->usbdev->tx_freeq);
    up(&buf->usbdev->tx_sema);
}

static int hgic_usb_tx_packet(void *bus, struct sk_buff *skb)
{
    int ret = 0;
    int len = ALIGN(skb->len, 4);
    struct hgic_usb_buf *buf    = NULL;
    struct hgic_usb     *usbdev = container_of(bus, struct hgic_usb, bus);

    if ((len & (usbdev->ep_out_size - 1)) == 0) {
        len += 4;
    }
    if (usbdev->status & (HGIC_USB_STATUS_STOP | HGIC_USB_STATUS_ERR)) {
        ret = -EIO;
        goto __fail;
    }

    ret = down_timeout(&usbdev->tx_sema, 1000);
    if(ret){
        ret = -EIO;
        goto __fail;        
    }
    
    buf = hgic_usb_deq(usbdev, &usbdev->tx_freeq);
    if (buf == NULL) {
        ret = -ENOMEM;
        goto __fail;
    }
    buf->skb = skb;
    usb_fill_bulk_urb(buf->urb, usbdev->udev,
                      usb_sndbulkpipe(usbdev->udev, usbdev->ep_out),
                      skb->data, len, /*ALIGN(skb->len, 4)*/
                      hgic_usb_tx_complete, buf);
    buf->urb->transfer_flags |= URB_ZERO_PACKET;
    ret = usb_submit_urb(buf->urb, GFP_ATOMIC);
    if (ret) {
        hgic_err("usb_submit_urb failed, ret:%d\n", ret);
        goto __fail;
    }

    return ret;

__fail:
    if (buf) {
        hgic_usb_enq(buf, &usbdev->tx_freeq);
    }
    usbdev->bus.tx_complete(usbdev->bus.bus_priv, skb, 0);
    return ret;
}

static struct hgic_bus hgic_bus_usb = {
    .type = HGIC_BUS_USB,
    .drv_tx_headroom = USB_TX_HEADROM,
    .tx_packet = hgic_usb_tx_packet,
    .bootdl_pktlen = 2048,
    .bootdl_cksum = HGIC_BUS_BOOTDL_CHECK_0XFD,
};

static int hgic_usb_probe(struct usb_interface *intf, const struct usb_device_id *id)
{
    int i   = 0;
    int ret = 0;
    struct usb_device *udev = NULL;
    struct hgic_usb   *usbdev = NULL;
    struct usb_host_interface *iface_desc = NULL;
    struct usb_endpoint_descriptor *endpoint = NULL;

    hgic_dbg("new usb card: vendor:%x, id:%x\n", id->idVendor, id->idProduct);
    udev = interface_to_usbdev(intf);
    iface_desc = intf->cur_altsetting;
    usbdev = kzalloc(sizeof(struct hgic_usb), GFP_KERNEL);
    if (!usbdev) {
        return -ENOMEM;
    }

    memset(usbdev, 0, sizeof(struct hgic_usb));
    usbdev->udev = udev;
    usbdev->bus = hgic_bus_usb;
    usbdev->bus.dev_id = id->idProduct;
    usbdev->status = HGIC_USB_STATUS_STOP;

    for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) {
        endpoint = &iface_desc->endpoint[i].desc;
        if (usb_endpoint_is_bulk_in(endpoint)) {
            usbdev->ep_in_size = le16_to_cpu(endpoint->wMaxPacketSize);
            usbdev->ep_in = usb_endpoint_num(endpoint);
            hgic_dbg("IN  BULK: ep_in_size:%x, ep_in:%x\n", usbdev->ep_in_size, usbdev->ep_in);
        } else if (usb_endpoint_is_bulk_out(endpoint)) {
            usbdev->ep_out_size = le16_to_cpu(endpoint->wMaxPacketSize);
            usbdev->ep_out = usb_endpoint_num(endpoint);
            hgic_dbg("OUT BULK: ep_out_size:%x, ep_out:%x\n", usbdev->ep_out_size, usbdev->ep_out);
        }
    }
    usbdev->bus.blk_size = usbdev->ep_out_size;
    
    spin_lock_init(&usbdev->qlock);
    INIT_LIST_HEAD(&usbdev->tx_freeq);
    INIT_LIST_HEAD(&usbdev->rx_freeq);
    INIT_LIST_HEAD(&usbdev->used);
    ret = hgic_usb_qinit(usbdev, &usbdev->tx_freeq, txq_cnt);
    sema_init(&usbdev->tx_sema, ret);
    hgic_dbg("usb txq:%d\r\n", ret);
    ret = hgic_usb_qinit(usbdev, &usbdev->rx_freeq, rxq_cnt);
    hgic_dbg("usb rxq:%d\r\n", ret);

    hgic_core_probe(&udev->dev, &usbdev->bus);
    if (!usbdev->bus.bus_priv) {
        ret = -ENOMEM;
        goto __failed;
    }

    ret = hgic_usb_submit_rx_urbs(usbdev);
    if (ret) {
        goto __failed;
    }
    usb_get_dev(udev);
    usb_set_intfdata(intf, usbdev);
    usbdev->status &= ~HGIC_USB_STATUS_STOP;
    hgic_core_probe_post(usbdev->bus.bus_priv);
    return ret;

__failed:
    hgic_core_remove(usbdev->bus.bus_priv);
    hgic_usb_free(usbdev);
    kfree(usbdev);
    return -1;
}

static void hgic_usb_disconnect(struct usb_interface *intf)
{
    struct hgic_usb *usbdev = usb_get_intfdata(intf);
    hgic_dbg("hgic_usb_disconnect>>>>\r\n");
    if (usbdev) {
        usbdev->status |= HGIC_USB_STATUS_STOP;
        hgic_core_remove(usbdev->bus.bus_priv);
        hgic_usb_free(usbdev);
        kfree(usbdev);
        usb_set_intfdata(intf, NULL);
    }
}

static struct usb_driver hgic_usb_driver = {
    .name = KBUILD_MODNAME,
    .probe = hgic_usb_probe,
    .disconnect = hgic_usb_disconnect,
    .id_table = hgic_usb_wdev_ids,
    .suspend = NULL,
    .resume = NULL,
    .supports_autosuspend = 1,
};

int __init hgic_usb_init(void)
{
    int ret = 0;

    hgic_dbg("Enter\n");
    ret = usb_register(&hgic_usb_driver);
    if (ret) {
        hgic_err("driver register failed: %d\n", ret);
    }
    hgic_dbg("Leave\n");
    return ret;
}

void __exit hgic_usb_exit(void)
{
    hgic_dbg("Enter\n");
    usb_deregister(&hgic_usb_driver);
    hgic_dbg("Leave\n");
}
#ifndef CONFIG_HGIC_USBIN
module_init(hgic_usb_init);
module_exit(hgic_usb_exit);
MODULE_DESCRIPTION("HUGE-IC WLAN Driver");
MODULE_AUTHOR("Dongyun");
MODULE_LICENSE("GPL");
#endif