/*
 * Copyright (c) 2010-2011 Atheros Communications Inc.
 *
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <linux/unaligned.h>
#include "htc.h"

MODULE_FIRMWARE(HTC_7010_MODULE_FW);
MODULE_FIRMWARE(HTC_9271_MODULE_FW);

static const struct usb_device_id ath9k_hif_usb_ids[] = {
        { USB_DEVICE(0x0cf3, 0x9271) }, /* Atheros */
        { USB_DEVICE(0x0cf3, 0x1006) }, /* Atheros */
        { USB_DEVICE(0x0846, 0x9030) }, /* Netgear N150 */
        { USB_DEVICE(0x07b8, 0x9271) }, /* Altai WA1011N-GU */
        { USB_DEVICE(0x07D1, 0x3A10) }, /* Dlink Wireless 150 */
        { USB_DEVICE(0x13D3, 0x3327) }, /* Azurewave */
        { USB_DEVICE(0x13D3, 0x3328) }, /* Azurewave */
        { USB_DEVICE(0x13D3, 0x3346) }, /* IMC Networks */
        { USB_DEVICE(0x13D3, 0x3348) }, /* Azurewave */
        { USB_DEVICE(0x13D3, 0x3349) }, /* Azurewave */
        { USB_DEVICE(0x13D3, 0x3350) }, /* Azurewave */
        { USB_DEVICE(0x04CA, 0x4605) }, /* Liteon */
        { USB_DEVICE(0x040D, 0x3801) }, /* VIA */
        { USB_DEVICE(0x0cf3, 0xb003) }, /* Ubiquiti WifiStation Ext */
        { USB_DEVICE(0x0cf3, 0xb002) }, /* Ubiquiti WifiStation */
        { USB_DEVICE(0x057c, 0x8403) }, /* AVM FRITZ!WLAN 11N v2 USB */
        { USB_DEVICE(0x0471, 0x209e) }, /* Philips (or NXP) PTA01 */
        { USB_DEVICE(0x1eda, 0x2315) }, /* AirTies */

        { USB_DEVICE(0x0cf3, 0x7015),
          .driver_info = AR9287_USB },  /* Atheros */

        { USB_DEVICE(0x0cf3, 0x7010),
          .driver_info = AR9280_USB },  /* Atheros */
        { USB_DEVICE(0x0846, 0x9018),
          .driver_info = AR9280_USB },  /* Netgear WNDA3200 */
        { USB_DEVICE(0x083A, 0xA704),
          .driver_info = AR9280_USB },  /* SMC Networks */
        { USB_DEVICE(0x0411, 0x017f),
          .driver_info = AR9280_USB },  /* Sony UWA-BR100 */
        { USB_DEVICE(0x0411, 0x0197),
          .driver_info = AR9280_USB },  /* Buffalo WLI-UV-AG300P */
        { USB_DEVICE(0x04da, 0x3904),
          .driver_info = AR9280_USB },
        { USB_DEVICE(0x0930, 0x0a08),
          .driver_info = AR9280_USB },  /* Toshiba WLM-20U2 and GN-1080 */

        { USB_DEVICE(0x0cf3, 0x20ff),
          .driver_info = STORAGE_DEVICE },

        { },
};

MODULE_DEVICE_TABLE(usb, ath9k_hif_usb_ids);

static int __hif_usb_tx(struct hif_device_usb *hif_dev);

static void hif_usb_regout_cb(struct urb *urb)
{
        struct cmd_buf *cmd = urb->context;

        switch (urb->status) {
        case 0:
                break;
        case -ENOENT:
        case -ECONNRESET:
        case -ENODEV:
        case -ESHUTDOWN:
                goto free;
        default:
                break;
        }

        if (cmd) {
                ath9k_htc_txcompletion_cb(cmd->hif_dev->htc_handle,
                                          cmd->skb, true);
                kfree(cmd);
        }

        return;
free:
        kfree_skb(cmd->skb);
        kfree(cmd);
}

static int hif_usb_send_regout(struct hif_device_usb *hif_dev,
                               struct sk_buff *skb)
{
        struct urb *urb;
        struct cmd_buf *cmd;
        int ret = 0;

        urb = usb_alloc_urb(0, GFP_KERNEL);
        if (urb == NULL)
                return -ENOMEM;

        cmd = kzalloc_obj(*cmd);
        if (cmd == NULL) {
                usb_free_urb(urb);
                return -ENOMEM;
        }

        cmd->skb = skb;
        cmd->hif_dev = hif_dev;

        usb_fill_int_urb(urb, hif_dev->udev,
                         usb_sndintpipe(hif_dev->udev, USB_REG_OUT_PIPE),
                         skb->data, skb->len,
                         hif_usb_regout_cb, cmd, 1);

        usb_anchor_urb(urb, &hif_dev->regout_submitted);
        ret = usb_submit_urb(urb, GFP_KERNEL);
        if (ret) {
                usb_unanchor_urb(urb);
                kfree(cmd);
        }
        usb_free_urb(urb);

        return ret;
}

static void hif_usb_mgmt_cb(struct urb *urb)
{
        struct cmd_buf *cmd = urb->context;
        struct hif_device_usb *hif_dev;
        unsigned long flags;
        bool txok = true;

        if (!cmd || !cmd->skb || !cmd->hif_dev)
                return;

        hif_dev = cmd->hif_dev;

        switch (urb->status) {
        case 0:
                break;
        case -ENOENT:
        case -ECONNRESET:
        case -ENODEV:
        case -ESHUTDOWN:
                txok = false;

                /*
                 * If the URBs are being flushed, no need to complete
                 * this packet.
                 */
                spin_lock_irqsave(&hif_dev->tx.tx_lock, flags);
                if (hif_dev->tx.flags & HIF_USB_TX_FLUSH) {
                        spin_unlock_irqrestore(&hif_dev->tx.tx_lock, flags);
                        dev_kfree_skb_any(cmd->skb);
                        kfree(cmd);
                        return;
                }
                spin_unlock_irqrestore(&hif_dev->tx.tx_lock, flags);

                break;
        default:
                txok = false;
                break;
        }

        skb_pull(cmd->skb, 4);
        ath9k_htc_txcompletion_cb(cmd->hif_dev->htc_handle,
                                  cmd->skb, txok);
        kfree(cmd);
}

static int hif_usb_send_mgmt(struct hif_device_usb *hif_dev,
                             struct sk_buff *skb)
{
        struct urb *urb;
        struct cmd_buf *cmd;
        int ret = 0;
        __le16 *hdr;

        urb = usb_alloc_urb(0, GFP_ATOMIC);
        if (urb == NULL)
                return -ENOMEM;

        cmd = kzalloc_obj(*cmd, GFP_ATOMIC);
        if (cmd == NULL) {
                usb_free_urb(urb);
                return -ENOMEM;
        }

        cmd->skb = skb;
        cmd->hif_dev = hif_dev;

        hdr = skb_push(skb, 4);
        *hdr++ = cpu_to_le16(skb->len - 4);
        *hdr++ = cpu_to_le16(ATH_USB_TX_STREAM_MODE_TAG);

        usb_fill_bulk_urb(urb, hif_dev->udev,
                         usb_sndbulkpipe(hif_dev->udev, USB_WLAN_TX_PIPE),
                         skb->data, skb->len,
                         hif_usb_mgmt_cb, cmd);

        usb_anchor_urb(urb, &hif_dev->mgmt_submitted);
        ret = usb_submit_urb(urb, GFP_ATOMIC);
        if (ret) {
                usb_unanchor_urb(urb);
                kfree(cmd);
        }
        usb_free_urb(urb);

        return ret;
}

static inline void ath9k_skb_queue_purge(struct hif_device_usb *hif_dev,
                                         struct sk_buff_head *list)
{
        struct sk_buff *skb;

        while ((skb = __skb_dequeue(list)) != NULL) {
                dev_kfree_skb_any(skb);
        }
}

static inline void ath9k_skb_queue_complete(struct hif_device_usb *hif_dev,
                                            struct sk_buff_head *queue,
                                            bool txok)
{
        struct sk_buff *skb;

        while ((skb = __skb_dequeue(queue)) != NULL) {
#ifdef CONFIG_ATH9K_HTC_DEBUGFS
                int ln = skb->len;
#endif
                ath9k_htc_txcompletion_cb(hif_dev->htc_handle,
                                          skb, txok);
                if (txok) {
                        TX_STAT_INC(hif_dev, skb_success);
                        TX_STAT_ADD(hif_dev, skb_success_bytes, ln);
                }
                else
                        TX_STAT_INC(hif_dev, skb_failed);
        }
}

static void hif_usb_tx_cb(struct urb *urb)
{
        struct tx_buf *tx_buf = urb->context;
        struct hif_device_usb *hif_dev;
        bool txok = true;

        if (!tx_buf || !tx_buf->hif_dev)
                return;

        hif_dev = tx_buf->hif_dev;

        switch (urb->status) {
        case 0:
                break;
        case -ENOENT:
        case -ECONNRESET:
        case -ENODEV:
        case -ESHUTDOWN:
                txok = false;

                /*
                 * If the URBs are being flushed, no need to add this
                 * URB to the free list.
                 */
                spin_lock(&hif_dev->tx.tx_lock);
                if (hif_dev->tx.flags & HIF_USB_TX_FLUSH) {
                        spin_unlock(&hif_dev->tx.tx_lock);
                        ath9k_skb_queue_purge(hif_dev, &tx_buf->skb_queue);
                        return;
                }
                spin_unlock(&hif_dev->tx.tx_lock);

                break;
        default:
                txok = false;
                break;
        }

        ath9k_skb_queue_complete(hif_dev, &tx_buf->skb_queue, txok);

        /* Re-initialize the SKB queue */
        tx_buf->len = tx_buf->offset = 0;
        __skb_queue_head_init(&tx_buf->skb_queue);

        /* Add this TX buffer to the free list */
        spin_lock(&hif_dev->tx.tx_lock);
        list_move_tail(&tx_buf->list, &hif_dev->tx.tx_buf);
        hif_dev->tx.tx_buf_cnt++;
        if (!(hif_dev->tx.flags & HIF_USB_TX_STOP))
                __hif_usb_tx(hif_dev); /* Check for pending SKBs */
        TX_STAT_INC(hif_dev, buf_completed);
        spin_unlock(&hif_dev->tx.tx_lock);
}

/* TX lock has to be taken */
static int __hif_usb_tx(struct hif_device_usb *hif_dev)
{
        struct tx_buf *tx_buf = NULL;
        struct sk_buff *nskb = NULL;
        int ret = 0, i;
        u16 tx_skb_cnt = 0;
        u8 *buf;
        __le16 *hdr;

        if (hif_dev->tx.tx_skb_cnt == 0)
                return 0;

        /* Check if a free TX buffer is available */
        if (list_empty(&hif_dev->tx.tx_buf))
                return 0;

        tx_buf = list_first_entry(&hif_dev->tx.tx_buf, struct tx_buf, list);
        list_move_tail(&tx_buf->list, &hif_dev->tx.tx_pending);
        hif_dev->tx.tx_buf_cnt--;

        tx_skb_cnt = min_t(u16, hif_dev->tx.tx_skb_cnt, MAX_TX_AGGR_NUM);

        for (i = 0; i < tx_skb_cnt; i++) {
                nskb = __skb_dequeue(&hif_dev->tx.tx_skb_queue);

                /* Should never be NULL */
                BUG_ON(!nskb);

                hif_dev->tx.tx_skb_cnt--;

                buf = tx_buf->buf;
                buf += tx_buf->offset;
                hdr = (__le16 *)buf;
                *hdr++ = cpu_to_le16(nskb->len);
                *hdr++ = cpu_to_le16(ATH_USB_TX_STREAM_MODE_TAG);
                buf += 4;
                memcpy(buf, nskb->data, nskb->len);
                tx_buf->len = nskb->len + 4;

                if (i < (tx_skb_cnt - 1))
                        tx_buf->offset += (((tx_buf->len - 1) / 4) + 1) * 4;

                if (i == (tx_skb_cnt - 1))
                        tx_buf->len += tx_buf->offset;

                __skb_queue_tail(&tx_buf->skb_queue, nskb);
                TX_STAT_INC(hif_dev, skb_queued);
        }

        usb_fill_bulk_urb(tx_buf->urb, hif_dev->udev,
                          usb_sndbulkpipe(hif_dev->udev, USB_WLAN_TX_PIPE),
                          tx_buf->buf, tx_buf->len,
                          hif_usb_tx_cb, tx_buf);

        ret = usb_submit_urb(tx_buf->urb, GFP_ATOMIC);
        if (ret) {
                tx_buf->len = tx_buf->offset = 0;
                ath9k_skb_queue_complete(hif_dev, &tx_buf->skb_queue, false);
                __skb_queue_head_init(&tx_buf->skb_queue);
                list_move_tail(&tx_buf->list, &hif_dev->tx.tx_buf);
                hif_dev->tx.tx_buf_cnt++;
        } else {
                TX_STAT_INC(hif_dev, buf_queued);
        }

        return ret;
}

static int hif_usb_send_tx(struct hif_device_usb *hif_dev, struct sk_buff *skb)
{
        struct ath9k_htc_tx_ctl *tx_ctl;
        unsigned long flags;
        int ret = 0;

        spin_lock_irqsave(&hif_dev->tx.tx_lock, flags);

        if (hif_dev->tx.flags & HIF_USB_TX_STOP) {
                spin_unlock_irqrestore(&hif_dev->tx.tx_lock, flags);
                return -ENODEV;
        }

        /* Check if the max queue count has been reached */
        if (hif_dev->tx.tx_skb_cnt > MAX_TX_BUF_NUM) {
                spin_unlock_irqrestore(&hif_dev->tx.tx_lock, flags);
                return -ENOMEM;
        }

        spin_unlock_irqrestore(&hif_dev->tx.tx_lock, flags);

        tx_ctl = HTC_SKB_CB(skb);

        /* Mgmt/Beacon frames don't use the TX buffer pool */
        if ((tx_ctl->type == ATH9K_HTC_MGMT) ||
            (tx_ctl->type == ATH9K_HTC_BEACON)) {
                ret = hif_usb_send_mgmt(hif_dev, skb);
        }

        spin_lock_irqsave(&hif_dev->tx.tx_lock, flags);

        if ((tx_ctl->type == ATH9K_HTC_NORMAL) ||
            (tx_ctl->type == ATH9K_HTC_AMPDU)) {
                __skb_queue_tail(&hif_dev->tx.tx_skb_queue, skb);
                hif_dev->tx.tx_skb_cnt++;
        }

        /* Check if AMPDUs have to be sent immediately */
        if ((hif_dev->tx.tx_buf_cnt == MAX_TX_URB_NUM) &&
            (hif_dev->tx.tx_skb_cnt < 2)) {
                __hif_usb_tx(hif_dev);
        }

        spin_unlock_irqrestore(&hif_dev->tx.tx_lock, flags);

        return ret;
}

static void hif_usb_start(void *hif_handle)
{
        struct hif_device_usb *hif_dev = hif_handle;
        unsigned long flags;

        hif_dev->flags |= HIF_USB_START;

        spin_lock_irqsave(&hif_dev->tx.tx_lock, flags);
        hif_dev->tx.flags &= ~HIF_USB_TX_STOP;
        spin_unlock_irqrestore(&hif_dev->tx.tx_lock, flags);
}

static void hif_usb_stop(void *hif_handle)
{
        struct hif_device_usb *hif_dev = hif_handle;
        struct tx_buf *tx_buf = NULL, *tx_buf_tmp = NULL;
        unsigned long flags;

        spin_lock_irqsave(&hif_dev->tx.tx_lock, flags);
        ath9k_skb_queue_complete(hif_dev, &hif_dev->tx.tx_skb_queue, false);
        hif_dev->tx.tx_skb_cnt = 0;
        hif_dev->tx.flags |= HIF_USB_TX_STOP;
        spin_unlock_irqrestore(&hif_dev->tx.tx_lock, flags);

        /* The pending URBs have to be canceled. */
        spin_lock_irqsave(&hif_dev->tx.tx_lock, flags);
        list_for_each_entry_safe(tx_buf, tx_buf_tmp,
                                 &hif_dev->tx.tx_pending, list) {
                usb_get_urb(tx_buf->urb);
                spin_unlock_irqrestore(&hif_dev->tx.tx_lock, flags);
                usb_kill_urb(tx_buf->urb);
                list_del(&tx_buf->list);
                usb_free_urb(tx_buf->urb);
                kfree(tx_buf->buf);
                kfree(tx_buf);
                spin_lock_irqsave(&hif_dev->tx.tx_lock, flags);
        }
        spin_unlock_irqrestore(&hif_dev->tx.tx_lock, flags);

        usb_kill_anchored_urbs(&hif_dev->mgmt_submitted);
}

static int hif_usb_send(void *hif_handle, u8 pipe_id, struct sk_buff *skb)
{
        struct hif_device_usb *hif_dev = hif_handle;
        int ret = 0;

        switch (pipe_id) {
        case USB_WLAN_TX_PIPE:
                ret = hif_usb_send_tx(hif_dev, skb);
                break;
        case USB_REG_OUT_PIPE:
                ret = hif_usb_send_regout(hif_dev, skb);
                break;
        default:
                dev_err(&hif_dev->udev->dev,
                        "ath9k_htc: Invalid TX pipe: %d\n", pipe_id);
                ret = -EINVAL;
                break;
        }

        return ret;
}

static inline bool check_index(struct sk_buff *skb, u8 idx)
{
        struct ath9k_htc_tx_ctl *tx_ctl;

        tx_ctl = HTC_SKB_CB(skb);

        if ((tx_ctl->type == ATH9K_HTC_AMPDU) &&
            (tx_ctl->sta_idx == idx))
                return true;

        return false;
}

static void hif_usb_sta_drain(void *hif_handle, u8 idx)
{
        struct hif_device_usb *hif_dev = hif_handle;
        struct sk_buff *skb, *tmp;
        unsigned long flags;

        spin_lock_irqsave(&hif_dev->tx.tx_lock, flags);

        skb_queue_walk_safe(&hif_dev->tx.tx_skb_queue, skb, tmp) {
                if (check_index(skb, idx)) {
                        __skb_unlink(skb, &hif_dev->tx.tx_skb_queue);
                        ath9k_htc_txcompletion_cb(hif_dev->htc_handle,
                                                  skb, false);
                        hif_dev->tx.tx_skb_cnt--;
                        TX_STAT_INC(hif_dev, skb_failed);
                }
        }

        spin_unlock_irqrestore(&hif_dev->tx.tx_lock, flags);
}

static struct ath9k_htc_hif hif_usb = {
        .transport = ATH9K_HIF_USB,
        .name = "ath9k_hif_usb",

        .control_ul_pipe = USB_REG_OUT_PIPE,
        .control_dl_pipe = USB_REG_IN_PIPE,

        .start = hif_usb_start,
        .stop = hif_usb_stop,
        .sta_drain = hif_usb_sta_drain,
        .send = hif_usb_send,
};

/* Need to free remain_skb allocated in ath9k_hif_usb_rx_stream
 * in case ath9k_hif_usb_rx_stream wasn't called next time to
 * process the buffer and subsequently free it.
 */
static void ath9k_hif_usb_free_rx_remain_skb(struct hif_device_usb *hif_dev)
{
        unsigned long flags;

        spin_lock_irqsave(&hif_dev->rx_lock, flags);
        if (hif_dev->remain_skb) {
                dev_kfree_skb_any(hif_dev->remain_skb);
                hif_dev->remain_skb = NULL;
                hif_dev->rx_remain_len = 0;
                RX_STAT_INC(hif_dev, skb_dropped);
        }
        spin_unlock_irqrestore(&hif_dev->rx_lock, flags);
}

static void ath9k_hif_usb_rx_stream(struct hif_device_usb *hif_dev,
                                    struct sk_buff *skb)
{
        struct sk_buff *nskb, *skb_pool[MAX_PKT_NUM_IN_TRANSFER];
        int index = 0, i, len = skb->len;
        int rx_remain_len, rx_pkt_len;
        u16 pool_index = 0;
        u8 *ptr;

        spin_lock(&hif_dev->rx_lock);

        rx_remain_len = hif_dev->rx_remain_len;
        rx_pkt_len = hif_dev->rx_transfer_len;

        if (rx_remain_len != 0) {
                struct sk_buff *remain_skb = hif_dev->remain_skb;

                if (remain_skb) {
                        ptr = (u8 *) remain_skb->data;

                        index = rx_remain_len;
                        rx_remain_len -= hif_dev->rx_pad_len;
                        ptr += rx_pkt_len;

                        memcpy(ptr, skb->data, rx_remain_len);

                        rx_pkt_len += rx_remain_len;
                        skb_put(remain_skb, rx_pkt_len);

                        skb_pool[pool_index++] = remain_skb;
                        hif_dev->remain_skb = NULL;
                        hif_dev->rx_remain_len = 0;
                } else {
                        index = rx_remain_len;
                }
        }

        spin_unlock(&hif_dev->rx_lock);

        while (index < len) {
                u16 pkt_len;
                u16 pkt_tag;
                u16 pad_len;
                int chk_idx;

                ptr = (u8 *) skb->data;

                pkt_len = get_unaligned_le16(ptr + index);
                pkt_tag = get_unaligned_le16(ptr + index + 2);

                /* It is supposed that if we have an invalid pkt_tag or
                 * pkt_len then the whole input SKB is considered invalid
                 * and dropped; the associated packets already in skb_pool
                 * are dropped, too.
                 */
                if (pkt_tag != ATH_USB_RX_STREAM_MODE_TAG) {
                        RX_STAT_INC(hif_dev, skb_dropped);
                        goto invalid_pkt;
                }

                if (pkt_len > 2 * MAX_RX_BUF_SIZE) {
                        dev_err(&hif_dev->udev->dev,
                                "ath9k_htc: invalid pkt_len (%x)\n", pkt_len);
                        RX_STAT_INC(hif_dev, skb_dropped);
                        goto invalid_pkt;
                }

                pad_len = 4 - (pkt_len & 0x3);
                if (pad_len == 4)
                        pad_len = 0;

                chk_idx = index;
                index = index + 4 + pkt_len + pad_len;

                if (index > MAX_RX_BUF_SIZE) {
                        spin_lock(&hif_dev->rx_lock);
                        nskb = __dev_alloc_skb(pkt_len + 32, GFP_ATOMIC);
                        if (!nskb) {
                                dev_err(&hif_dev->udev->dev,
                                        "ath9k_htc: RX memory allocation error\n");
                                spin_unlock(&hif_dev->rx_lock);
                                goto err;
                        }

                        hif_dev->rx_remain_len = index - MAX_RX_BUF_SIZE;
                        hif_dev->rx_transfer_len =
                                MAX_RX_BUF_SIZE - chk_idx - 4;
                        hif_dev->rx_pad_len = pad_len;

                        skb_reserve(nskb, 32);
                        RX_STAT_INC(hif_dev, skb_allocated);

                        memcpy(nskb->data, &(skb->data[chk_idx+4]),
                               hif_dev->rx_transfer_len);

                        /* Record the buffer pointer */
                        hif_dev->remain_skb = nskb;
                        spin_unlock(&hif_dev->rx_lock);
                } else {
                        if (pool_index == MAX_PKT_NUM_IN_TRANSFER) {
                                dev_err(&hif_dev->udev->dev,
                                        "ath9k_htc: over RX MAX_PKT_NUM\n");
                                goto err;
                        }
                        nskb = __dev_alloc_skb(pkt_len + 32, GFP_ATOMIC);
                        if (!nskb) {
                                dev_err(&hif_dev->udev->dev,
                                        "ath9k_htc: RX memory allocation error\n");
                                goto err;
                        }
                        skb_reserve(nskb, 32);
                        RX_STAT_INC(hif_dev, skb_allocated);

                        memcpy(nskb->data, &(skb->data[chk_idx+4]), pkt_len);
                        skb_put(nskb, pkt_len);
                        skb_pool[pool_index++] = nskb;
                }
        }

err:
        for (i = 0; i < pool_index; i++) {
                RX_STAT_ADD(hif_dev, skb_completed_bytes, skb_pool[i]->len);
                ath9k_htc_rx_msg(hif_dev->htc_handle, skb_pool[i],
                                 skb_pool[i]->len, USB_WLAN_RX_PIPE);
                RX_STAT_INC(hif_dev, skb_completed);
        }
        return;
invalid_pkt:
        for (i = 0; i < pool_index; i++) {
                dev_kfree_skb_any(skb_pool[i]);
                RX_STAT_INC(hif_dev, skb_dropped);
        }
        return;
}

static void ath9k_hif_usb_rx_cb(struct urb *urb)
{
        struct rx_buf *rx_buf = urb->context;
        struct hif_device_usb *hif_dev = rx_buf->hif_dev;
        struct sk_buff *skb = rx_buf->skb;
        int ret;

        if (!skb)
                return;

        if (!hif_dev)
                goto free;

        switch (urb->status) {
        case 0:
                break;
        case -ENOENT:
        case -ECONNRESET:
        case -ENODEV:
        case -ESHUTDOWN:
                goto free;
        default:
                goto resubmit;
        }

        if (likely(urb->actual_length != 0)) {
                skb_put(skb, urb->actual_length);
                ath9k_hif_usb_rx_stream(hif_dev, skb);
        }

resubmit:
        __skb_set_length(skb, 0);

        usb_anchor_urb(urb, &hif_dev->rx_submitted);
        ret = usb_submit_urb(urb, GFP_ATOMIC);
        if (ret) {
                usb_unanchor_urb(urb);
                goto free;
        }

        return;
free:
        kfree_skb(skb);
        kfree(rx_buf);
}

static void ath9k_hif_usb_reg_in_cb(struct urb *urb)
{
        struct rx_buf *rx_buf = urb->context;
        struct hif_device_usb *hif_dev = rx_buf->hif_dev;
        struct sk_buff *skb = rx_buf->skb;
        int ret;

        if (!skb)
                return;

        if (!hif_dev)
                goto free_skb;

        switch (urb->status) {
        case 0:
                break;
        case -ENOENT:
        case -ECONNRESET:
        case -ENODEV:
        case -ESHUTDOWN:
                goto free_skb;
        default:
                __skb_set_length(skb, 0);

                goto resubmit;
        }

        if (likely(urb->actual_length != 0)) {
                skb_put(skb, urb->actual_length);

                /*
                 * Process the command first.
                 * skb is either freed here or passed to be
                 * managed to another callback function.
                 */
                ath9k_htc_rx_msg(hif_dev->htc_handle, skb,
                                 skb->len, USB_REG_IN_PIPE);

                skb = alloc_skb(MAX_REG_IN_BUF_SIZE, GFP_ATOMIC);
                if (!skb) {
                        dev_err(&hif_dev->udev->dev,
                                "ath9k_htc: REG_IN memory allocation failure\n");
                        goto free_rx_buf;
                }

                rx_buf->skb = skb;

                usb_fill_int_urb(urb, hif_dev->udev,
                                 usb_rcvintpipe(hif_dev->udev,
                                                 USB_REG_IN_PIPE),
                                 skb->data, MAX_REG_IN_BUF_SIZE,
                                 ath9k_hif_usb_reg_in_cb, rx_buf, 1);
        }

resubmit:
        usb_anchor_urb(urb, &hif_dev->reg_in_submitted);
        ret = usb_submit_urb(urb, GFP_ATOMIC);
        if (ret) {
                usb_unanchor_urb(urb);
                goto free_skb;
        }

        return;
free_skb:
        kfree_skb(skb);
free_rx_buf:
        kfree(rx_buf);
        urb->context = NULL;
}

static void ath9k_hif_usb_dealloc_tx_urbs(struct hif_device_usb *hif_dev)
{
        struct tx_buf *tx_buf = NULL, *tx_buf_tmp = NULL;
        unsigned long flags;

        spin_lock_irqsave(&hif_dev->tx.tx_lock, flags);
        list_for_each_entry_safe(tx_buf, tx_buf_tmp,
                                 &hif_dev->tx.tx_buf, list) {
                list_del(&tx_buf->list);
                usb_free_urb(tx_buf->urb);
                kfree(tx_buf->buf);
                kfree(tx_buf);
        }
        spin_unlock_irqrestore(&hif_dev->tx.tx_lock, flags);

        spin_lock_irqsave(&hif_dev->tx.tx_lock, flags);
        hif_dev->tx.flags |= HIF_USB_TX_FLUSH;
        spin_unlock_irqrestore(&hif_dev->tx.tx_lock, flags);

        spin_lock_irqsave(&hif_dev->tx.tx_lock, flags);
        list_for_each_entry_safe(tx_buf, tx_buf_tmp,
                                 &hif_dev->tx.tx_pending, list) {
                usb_get_urb(tx_buf->urb);
                spin_unlock_irqrestore(&hif_dev->tx.tx_lock, flags);
                usb_kill_urb(tx_buf->urb);
                list_del(&tx_buf->list);
                usb_free_urb(tx_buf->urb);
                kfree(tx_buf->buf);
                kfree(tx_buf);
                spin_lock_irqsave(&hif_dev->tx.tx_lock, flags);
        }
        spin_unlock_irqrestore(&hif_dev->tx.tx_lock, flags);

        usb_kill_anchored_urbs(&hif_dev->mgmt_submitted);
}

static int ath9k_hif_usb_alloc_tx_urbs(struct hif_device_usb *hif_dev)
{
        struct tx_buf *tx_buf;
        int i;

        INIT_LIST_HEAD(&hif_dev->tx.tx_buf);
        INIT_LIST_HEAD(&hif_dev->tx.tx_pending);
        spin_lock_init(&hif_dev->tx.tx_lock);
        __skb_queue_head_init(&hif_dev->tx.tx_skb_queue);
        init_usb_anchor(&hif_dev->mgmt_submitted);

        for (i = 0; i < MAX_TX_URB_NUM; i++) {
                tx_buf = kzalloc_obj(*tx_buf);
                if (!tx_buf)
                        goto err;

                tx_buf->buf = kzalloc(MAX_TX_BUF_SIZE, GFP_KERNEL);
                if (!tx_buf->buf)
                        goto err;

                tx_buf->urb = usb_alloc_urb(0, GFP_KERNEL);
                if (!tx_buf->urb)
                        goto err;

                tx_buf->hif_dev = hif_dev;
                __skb_queue_head_init(&tx_buf->skb_queue);

                list_add_tail(&tx_buf->list, &hif_dev->tx.tx_buf);
        }

        hif_dev->tx.tx_buf_cnt = MAX_TX_URB_NUM;

        return 0;
err:
        if (tx_buf) {
                kfree(tx_buf->buf);
                kfree(tx_buf);
        }
        ath9k_hif_usb_dealloc_tx_urbs(hif_dev);
        return -ENOMEM;
}

static void ath9k_hif_usb_dealloc_rx_urbs(struct hif_device_usb *hif_dev)
{
        usb_kill_anchored_urbs(&hif_dev->rx_submitted);
        ath9k_hif_usb_free_rx_remain_skb(hif_dev);
}

static int ath9k_hif_usb_alloc_rx_urbs(struct hif_device_usb *hif_dev)
{
        struct rx_buf *rx_buf = NULL;
        struct sk_buff *skb = NULL;
        struct urb *urb = NULL;
        int i, ret;

        init_usb_anchor(&hif_dev->rx_submitted);
        spin_lock_init(&hif_dev->rx_lock);

        for (i = 0; i < MAX_RX_URB_NUM; i++) {

                rx_buf = kzalloc_obj(*rx_buf);
                if (!rx_buf) {
                        ret = -ENOMEM;
                        goto err_rxb;
                }

                /* Allocate URB */
                urb = usb_alloc_urb(0, GFP_KERNEL);
                if (urb == NULL) {
                        ret = -ENOMEM;
                        goto err_urb;
                }

                /* Allocate buffer */
                skb = alloc_skb(MAX_RX_BUF_SIZE, GFP_KERNEL);
                if (!skb) {
                        ret = -ENOMEM;
                        goto err_skb;
                }

                rx_buf->hif_dev = hif_dev;
                rx_buf->skb = skb;

                usb_fill_bulk_urb(urb, hif_dev->udev,
                                  usb_rcvbulkpipe(hif_dev->udev,
                                                  USB_WLAN_RX_PIPE),
                                  skb->data, MAX_RX_BUF_SIZE,
                                  ath9k_hif_usb_rx_cb, rx_buf);

                /* Anchor URB */
                usb_anchor_urb(urb, &hif_dev->rx_submitted);

                /* Submit URB */
                ret = usb_submit_urb(urb, GFP_KERNEL);
                if (ret) {
                        usb_unanchor_urb(urb);
                        goto err_submit;
                }

                /*
                 * Drop reference count.
                 * This ensures that the URB is freed when killing them.
                 */
                usb_free_urb(urb);
        }

        return 0;

err_submit:
        kfree_skb(skb);
err_skb:
        usb_free_urb(urb);
err_urb:
        kfree(rx_buf);
err_rxb:
        ath9k_hif_usb_dealloc_rx_urbs(hif_dev);
        return ret;
}

static void ath9k_hif_usb_dealloc_reg_in_urbs(struct hif_device_usb *hif_dev)
{
        usb_kill_anchored_urbs(&hif_dev->reg_in_submitted);
}

static int ath9k_hif_usb_alloc_reg_in_urbs(struct hif_device_usb *hif_dev)
{
        struct rx_buf *rx_buf = NULL;
        struct sk_buff *skb = NULL;
        struct urb *urb = NULL;
        int i, ret;

        init_usb_anchor(&hif_dev->reg_in_submitted);

        for (i = 0; i < MAX_REG_IN_URB_NUM; i++) {

                rx_buf = kzalloc_obj(*rx_buf);
                if (!rx_buf) {
                        ret = -ENOMEM;
                        goto err_rxb;
                }

                /* Allocate URB */
                urb = usb_alloc_urb(0, GFP_KERNEL);
                if (urb == NULL) {
                        ret = -ENOMEM;
                        goto err_urb;
                }

                /* Allocate buffer */
                skb = alloc_skb(MAX_REG_IN_BUF_SIZE, GFP_KERNEL);
                if (!skb) {
                        ret = -ENOMEM;
                        goto err_skb;
                }

                rx_buf->hif_dev = hif_dev;
                rx_buf->skb = skb;

                usb_fill_int_urb(urb, hif_dev->udev,
                                  usb_rcvintpipe(hif_dev->udev,
                                                  USB_REG_IN_PIPE),
                                  skb->data, MAX_REG_IN_BUF_SIZE,
                                  ath9k_hif_usb_reg_in_cb, rx_buf, 1);

                /* Anchor URB */
                usb_anchor_urb(urb, &hif_dev->reg_in_submitted);

                /* Submit URB */
                ret = usb_submit_urb(urb, GFP_KERNEL);
                if (ret) {
                        usb_unanchor_urb(urb);
                        goto err_submit;
                }

                /*
                 * Drop reference count.
                 * This ensures that the URB is freed when killing them.
                 */
                usb_free_urb(urb);
        }

        return 0;

err_submit:
        kfree_skb(skb);
err_skb:
        usb_free_urb(urb);
err_urb:
        kfree(rx_buf);
err_rxb:
        ath9k_hif_usb_dealloc_reg_in_urbs(hif_dev);
        return ret;
}

static int ath9k_hif_usb_alloc_urbs(struct hif_device_usb *hif_dev)
{
        /* Register Write */
        init_usb_anchor(&hif_dev->regout_submitted);

        /* TX */
        if (ath9k_hif_usb_alloc_tx_urbs(hif_dev) < 0)
                goto err;

        /* RX */
        if (ath9k_hif_usb_alloc_rx_urbs(hif_dev) < 0)
                goto err_rx;

        /* Register Read */
        if (ath9k_hif_usb_alloc_reg_in_urbs(hif_dev) < 0)
                goto err_reg;

        return 0;
err_reg:
        ath9k_hif_usb_dealloc_rx_urbs(hif_dev);
err_rx:
        ath9k_hif_usb_dealloc_tx_urbs(hif_dev);
err:
        return -ENOMEM;
}

void ath9k_hif_usb_dealloc_urbs(struct hif_device_usb *hif_dev)
{
        usb_kill_anchored_urbs(&hif_dev->regout_submitted);
        ath9k_hif_usb_dealloc_reg_in_urbs(hif_dev);
        ath9k_hif_usb_dealloc_tx_urbs(hif_dev);
        ath9k_hif_usb_dealloc_rx_urbs(hif_dev);
}

static int ath9k_hif_usb_download_fw(struct hif_device_usb *hif_dev)
{
        int transfer, err;
        const void *data = hif_dev->fw_data;
        size_t len = hif_dev->fw_size;
        u32 addr = AR9271_FIRMWARE;
        u8 *buf = kzalloc(4096, GFP_KERNEL);
        u32 firm_offset;

        if (!buf)
                return -ENOMEM;

        while (len) {
                transfer = min_t(size_t, len, 4096);
                memcpy(buf, data, transfer);

                err = usb_control_msg(hif_dev->udev,
                                      usb_sndctrlpipe(hif_dev->udev, 0),
                                      FIRMWARE_DOWNLOAD, 0x40 | USB_DIR_OUT,
                                      addr >> 8, 0, buf, transfer,
                                      USB_MSG_TIMEOUT);
                if (err < 0) {
                        kfree(buf);
                        return err;
                }

                len -= transfer;
                data += transfer;
                addr += transfer;
        }
        kfree(buf);

        if (IS_AR7010_DEVICE(hif_dev->usb_device_id->driver_info))
                firm_offset = AR7010_FIRMWARE_TEXT;
        else
                firm_offset = AR9271_FIRMWARE_TEXT;

        /*
         * Issue FW download complete command to firmware.
         */
        err = usb_control_msg(hif_dev->udev, usb_sndctrlpipe(hif_dev->udev, 0),
                              FIRMWARE_DOWNLOAD_COMP,
                              0x40 | USB_DIR_OUT,
                              firm_offset >> 8, 0, NULL, 0, USB_MSG_TIMEOUT);
        if (err)
                return -EIO;

        dev_info(&hif_dev->udev->dev, "ath9k_htc: Transferred FW: %s, size: %ld\n",
                 hif_dev->fw_name, (unsigned long) hif_dev->fw_size);

        return 0;
}

static int ath9k_hif_usb_dev_init(struct hif_device_usb *hif_dev)
{
        int ret;

        ret = ath9k_hif_usb_download_fw(hif_dev);
        if (ret) {
                dev_err(&hif_dev->udev->dev,
                        "ath9k_htc: Firmware - %s download failed\n",
                        hif_dev->fw_name);
                return ret;
        }

        /* Alloc URBs */
        ret = ath9k_hif_usb_alloc_urbs(hif_dev);
        if (ret) {
                dev_err(&hif_dev->udev->dev,
                        "ath9k_htc: Unable to allocate URBs\n");
                return ret;
        }

        return 0;
}

static void ath9k_hif_usb_dev_deinit(struct hif_device_usb *hif_dev)
{
        ath9k_hif_usb_dealloc_urbs(hif_dev);
}

/*
 * If initialization fails or the FW cannot be retrieved,
 * detach the device.
 */
static void ath9k_hif_usb_firmware_fail(struct hif_device_usb *hif_dev)
{
        struct device *dev = &hif_dev->udev->dev;
        struct device *parent = dev->parent;

        complete_all(&hif_dev->fw_done);

        if (parent)
                device_lock(parent);

        device_release_driver(dev);

        if (parent)
                device_unlock(parent);
}

static void ath9k_hif_usb_firmware_cb(const struct firmware *fw, void *context);

/* taken from iwlwifi */
static int ath9k_hif_request_firmware(struct hif_device_usb *hif_dev,
                                      bool first)
{
        char index[8], *chip;
        int ret;

        if (first) {
                if (htc_use_dev_fw) {
                        hif_dev->fw_minor_index = FIRMWARE_MINOR_IDX_MAX + 1;
                        sprintf(index, "%s", "dev");
                } else {
                        hif_dev->fw_minor_index = FIRMWARE_MINOR_IDX_MAX;
                        sprintf(index, "%d", hif_dev->fw_minor_index);
                }
        } else {
                hif_dev->fw_minor_index--;
                sprintf(index, "%d", hif_dev->fw_minor_index);
        }

        /* test for FW 1.3 */
        if (MAJOR_VERSION_REQ == 1 && hif_dev->fw_minor_index == 3) {
                const char *filename;

                if (IS_AR7010_DEVICE(hif_dev->usb_device_id->driver_info))
                        filename = FIRMWARE_AR7010_1_1;
                else
                        filename = FIRMWARE_AR9271;

                /* expected fw locations:
                 * - htc_9271.fw   (stable version 1.3, deprecated)
                 */
                snprintf(hif_dev->fw_name, sizeof(hif_dev->fw_name),
                         "%s", filename);

        } else if (hif_dev->fw_minor_index < FIRMWARE_MINOR_IDX_MIN) {
                dev_err(&hif_dev->udev->dev, "no suitable firmware found!\n");

                return -ENOENT;
        } else {
                if (IS_AR7010_DEVICE(hif_dev->usb_device_id->driver_info))
                        chip = "7010";
                else
                        chip = "9271";

                /* expected fw locations:
                 * - ath9k_htc/htc_9271-1.dev.0.fw (development version)
                 * - ath9k_htc/htc_9271-1.4.0.fw   (stable version)
                 */
                snprintf(hif_dev->fw_name, sizeof(hif_dev->fw_name),
                         "%s/htc_%s-%d.%s.0.fw", HTC_FW_PATH,
                         chip, MAJOR_VERSION_REQ, index);
        }

        ret = request_firmware_nowait(THIS_MODULE, true, hif_dev->fw_name,
                                      &hif_dev->udev->dev, GFP_KERNEL,
                                      hif_dev, ath9k_hif_usb_firmware_cb);
        if (ret) {
                dev_err(&hif_dev->udev->dev,
                        "ath9k_htc: Async request for firmware %s failed\n",
                        hif_dev->fw_name);
                return ret;
        }

        dev_info(&hif_dev->udev->dev, "ath9k_htc: Firmware %s requested\n",
                 hif_dev->fw_name);

        return ret;
}

static void ath9k_hif_usb_firmware_cb(const struct firmware *fw, void *context)
{
        struct hif_device_usb *hif_dev = context;
        int ret;

        if (!fw) {
                ret = ath9k_hif_request_firmware(hif_dev, false);
                if (!ret)
                        return;

                dev_err(&hif_dev->udev->dev,
                        "ath9k_htc: Failed to get firmware %s\n",
                        hif_dev->fw_name);
                goto err_fw;
        }

        hif_dev->htc_handle = ath9k_htc_hw_alloc(hif_dev, &hif_usb,
                                                 &hif_dev->udev->dev);
        if (hif_dev->htc_handle == NULL)
                goto err_dev_alloc;

        hif_dev->fw_data = fw->data;
        hif_dev->fw_size = fw->size;

        /* Proceed with initialization */

        ret = ath9k_hif_usb_dev_init(hif_dev);
        if (ret)
                goto err_dev_init;

        ret = ath9k_htc_hw_init(hif_dev->htc_handle,
                                &hif_dev->interface->dev,
                                hif_dev->usb_device_id->idProduct,
                                hif_dev->udev->product,
                                hif_dev->usb_device_id->driver_info);
        if (ret) {
                ret = -EINVAL;
                goto err_htc_hw_init;
        }

        release_firmware(fw);
        hif_dev->flags |= HIF_USB_READY;
        complete_all(&hif_dev->fw_done);

        return;

err_htc_hw_init:
        ath9k_hif_usb_dev_deinit(hif_dev);
err_dev_init:
        ath9k_htc_hw_free(hif_dev->htc_handle);
err_dev_alloc:
        release_firmware(fw);
err_fw:
        ath9k_hif_usb_firmware_fail(hif_dev);
}

/*
 * An exact copy of the function from zd1211rw.
 */
static int send_eject_command(struct usb_interface *interface)
{
        struct usb_device *udev = interface_to_usbdev(interface);
        struct usb_host_interface *iface_desc = interface->cur_altsetting;
        struct usb_endpoint_descriptor *endpoint;
        unsigned char *cmd;
        u8 bulk_out_ep;
        int r;

        if (iface_desc->desc.bNumEndpoints < 2)
                return -ENODEV;

        /* Find bulk out endpoint */
        for (r = 1; r >= 0; r--) {
                endpoint = &iface_desc->endpoint[r].desc;
                if (usb_endpoint_dir_out(endpoint) &&
                    usb_endpoint_xfer_bulk(endpoint)) {
                        bulk_out_ep = endpoint->bEndpointAddress;
                        break;
                }
        }
        if (r == -1) {
                dev_err(&udev->dev,
                        "ath9k_htc: Could not find bulk out endpoint\n");
                return -ENODEV;
        }

        cmd = kzalloc(31, GFP_KERNEL);
        if (cmd == NULL)
                return -ENODEV;

        /* USB bulk command block */
        cmd[0] = 0x55;  /* bulk command signature */
        cmd[1] = 0x53;  /* bulk command signature */
        cmd[2] = 0x42;  /* bulk command signature */
        cmd[3] = 0x43;  /* bulk command signature */
        cmd[14] = 6;    /* command length */

        cmd[15] = 0x1b; /* SCSI command: START STOP UNIT */
        cmd[19] = 0x2;  /* eject disc */

        dev_info(&udev->dev, "Ejecting storage device...\n");
        r = usb_bulk_msg(udev, usb_sndbulkpipe(udev, bulk_out_ep),
                cmd, 31, NULL, 2 * USB_MSG_TIMEOUT);
        kfree(cmd);
        if (r)
                return r;

        /* At this point, the device disconnects and reconnects with the real
         * ID numbers. */

        usb_set_intfdata(interface, NULL);
        return 0;
}

static int ath9k_hif_usb_probe(struct usb_interface *interface,
                               const struct usb_device_id *id)
{
        struct usb_endpoint_descriptor *bulk_in, *bulk_out, *int_in, *int_out;
        struct usb_device *udev = interface_to_usbdev(interface);
        struct usb_host_interface *alt;
        struct hif_device_usb *hif_dev;
        int ret = 0;

        /* Verify the expected endpoints are present */
        alt = interface->cur_altsetting;
        if (usb_find_common_endpoints(alt, &bulk_in, &bulk_out, &int_in, &int_out) < 0 ||
            usb_endpoint_num(bulk_in) != USB_WLAN_RX_PIPE ||
            usb_endpoint_num(bulk_out) != USB_WLAN_TX_PIPE ||
            usb_endpoint_num(int_in) != USB_REG_IN_PIPE ||
            usb_endpoint_num(int_out) != USB_REG_OUT_PIPE) {
                dev_err(&udev->dev,
                        "ath9k_htc: Device endpoint numbers are not the expected ones\n");
                return -ENODEV;
        }

        if (id->driver_info == STORAGE_DEVICE)
                return send_eject_command(interface);

        hif_dev = kzalloc_obj(struct hif_device_usb);
        if (!hif_dev) {
                ret = -ENOMEM;
                goto err_alloc;
        }

        usb_get_dev(udev);

        hif_dev->udev = udev;
        hif_dev->interface = interface;
        hif_dev->usb_device_id = id;
#ifdef CONFIG_PM
        udev->reset_resume = 1;
#endif
        usb_set_intfdata(interface, hif_dev);

        init_completion(&hif_dev->fw_done);

        ret = ath9k_hif_request_firmware(hif_dev, true);
        if (ret)
                goto err_fw_req;

        return ret;

err_fw_req:
        usb_set_intfdata(interface, NULL);
        kfree(hif_dev);
        usb_put_dev(udev);
err_alloc:
        return ret;
}

static void ath9k_hif_usb_reboot(struct usb_device *udev)
{
        u32 reboot_cmd = 0xffffffff;
        void *buf;
        int ret;

        buf = kmemdup(&reboot_cmd, 4, GFP_KERNEL);
        if (!buf)
                return;

        ret = usb_interrupt_msg(udev, usb_sndintpipe(udev, USB_REG_OUT_PIPE),
                           buf, 4, NULL, USB_MSG_TIMEOUT);
        if (ret)
                dev_err(&udev->dev, "ath9k_htc: USB reboot failed\n");

        kfree(buf);
}

static void ath9k_hif_usb_disconnect(struct usb_interface *interface)
{
        struct usb_device *udev = interface_to_usbdev(interface);
        struct hif_device_usb *hif_dev = usb_get_intfdata(interface);
        bool unplugged = udev->state == USB_STATE_NOTATTACHED;

        if (!hif_dev)
                return;

        wait_for_completion(&hif_dev->fw_done);

        if (hif_dev->flags & HIF_USB_READY) {
                ath9k_htc_hw_deinit(hif_dev->htc_handle, unplugged);
                ath9k_htc_hw_free(hif_dev->htc_handle);
        }

        usb_set_intfdata(interface, NULL);

        /* If firmware was loaded we should drop it
         * go back to first stage bootloader. */
        if (!unplugged && (hif_dev->flags & HIF_USB_READY))
                ath9k_hif_usb_reboot(udev);

        kfree(hif_dev);
        dev_info(&udev->dev, "ath9k_htc: USB layer deinitialized\n");
        usb_put_dev(udev);
}

#ifdef CONFIG_PM
static int ath9k_hif_usb_suspend(struct usb_interface *interface,
                                 pm_message_t message)
{
        struct hif_device_usb *hif_dev = usb_get_intfdata(interface);

        /*
         * The device has to be set to FULLSLEEP mode in case no
         * interface is up.
         */
        if (!(hif_dev->flags & HIF_USB_START))
                ath9k_htc_suspend(hif_dev->htc_handle);

        wait_for_completion(&hif_dev->fw_done);

        if (hif_dev->flags & HIF_USB_READY)
                ath9k_hif_usb_dealloc_urbs(hif_dev);

        return 0;
}

static int ath9k_hif_usb_resume(struct usb_interface *interface)
{
        struct hif_device_usb *hif_dev = usb_get_intfdata(interface);
        struct htc_target *htc_handle = hif_dev->htc_handle;
        const struct firmware *fw;
        int ret;

        ret = ath9k_hif_usb_alloc_urbs(hif_dev);
        if (ret)
                return ret;

        if (!(hif_dev->flags & HIF_USB_READY)) {
                ret = -EIO;
                goto fail_resume;
        }

        /* request cached firmware during suspend/resume cycle */
        ret = request_firmware(&fw, hif_dev->fw_name,
                               &hif_dev->udev->dev);
        if (ret)
                goto fail_resume;

        hif_dev->fw_data = fw->data;
        hif_dev->fw_size = fw->size;
        ret = ath9k_hif_usb_download_fw(hif_dev);
        release_firmware(fw);
        if (ret)
                goto fail_resume;

        mdelay(100);

        ret = ath9k_htc_resume(htc_handle);

        if (ret)
                goto fail_resume;

        return 0;

fail_resume:
        ath9k_hif_usb_dealloc_urbs(hif_dev);

        return ret;
}
#endif

static struct usb_driver ath9k_hif_usb_driver = {
        .name = KBUILD_MODNAME,
        .probe = ath9k_hif_usb_probe,
        .disconnect = ath9k_hif_usb_disconnect,
#ifdef CONFIG_PM
        .suspend = ath9k_hif_usb_suspend,
        .resume = ath9k_hif_usb_resume,
        .reset_resume = ath9k_hif_usb_resume,
#endif
        .id_table = ath9k_hif_usb_ids,
        .soft_unbind = 1,
        .disable_hub_initiated_lpm = 1,
};

int ath9k_hif_usb_init(void)
{
        return usb_register(&ath9k_hif_usb_driver);
}

void ath9k_hif_usb_exit(void)
{
        usb_deregister(&ath9k_hif_usb_driver);
}