/*
 * 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 <asm/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(0x1668, 0x1200),
	  .driver_info = AR9287_USB },  /* Verizon */

	{ 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 = (struct cmd_buf *)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(sizeof(*cmd), GFP_KERNEL);
	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 = (struct cmd_buf *)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(sizeof(*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(skb_success);
			TX_STAT_ADD(skb_success_bytes, ln);
		}
		else
			TX_STAT_INC(skb_failed);
	}
}

static void hif_usb_tx_cb(struct urb *urb)
{
	struct tx_buf *tx_buf = (struct 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(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(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++;
	}

	if (!ret)
		TX_STAT_INC(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. */
	list_for_each_entry_safe(tx_buf, tx_buf_tmp,
				 &hif_dev->tx.tx_pending, list) {
		usb_kill_urb(tx_buf->urb);
	}

	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(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,
};

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;
			hif_dev->rx_remain_len = 0;
			skb_put(remain_skb, rx_pkt_len);

			skb_pool[pool_index++] = remain_skb;

		} 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);

		if (pkt_tag != ATH_USB_RX_STREAM_MODE_TAG) {
			RX_STAT_INC(skb_dropped);
			return;
		}

		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);
			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;

			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;
			}
			skb_reserve(nskb, 32);
			RX_STAT_INC(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(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(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(skb_completed);
	}
}

static void ath9k_hif_usb_rx_cb(struct urb *urb)
{
	struct rx_buf *rx_buf = (struct 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_reset_tail_pointer(skb);
	skb_trim(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 = (struct rx_buf *)urb->context;
	struct hif_device_usb *hif_dev = rx_buf->hif_dev;
	struct sk_buff *skb = rx_buf->skb;
	struct sk_buff *nskb;
	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:
		skb_reset_tail_pointer(skb);
		skb_trim(skb, 0);

		goto resubmit;
	}

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

		/* Process the command first */
		ath9k_htc_rx_msg(hif_dev->htc_handle, skb,
				 skb->len, USB_REG_IN_PIPE);


		nskb = alloc_skb(MAX_REG_IN_BUF_SIZE, GFP_ATOMIC);
		if (!nskb) {
			dev_err(&hif_dev->udev->dev,
				"ath9k_htc: REG_IN memory allocation failure\n");
			urb->context = NULL;
			return;
		}

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

	return;
free:
	kfree_skb(skb);
	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;

	list_for_each_entry_safe(tx_buf, tx_buf_tmp,
				 &hif_dev->tx.tx_buf, list) {
		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);
	hif_dev->tx.flags |= HIF_USB_TX_FLUSH;
	spin_unlock_irqrestore(&hif_dev->tx.tx_lock, flags);

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

	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(sizeof(*tx_buf), GFP_KERNEL);
		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);
}

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(sizeof(*rx_buf), GFP_KERNEL);
		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(sizeof(*rx_buf), GFP_KERNEL);
		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, depricated)
		 */
		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_device *udev = interface_to_usbdev(interface);
	struct hif_device_usb *hif_dev;
	int ret = 0;

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

	hif_dev = kzalloc(sizeof(struct hif_device_usb), GFP_KERNEL);
	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) ? true : false;

	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_hif_usb_dev_deinit(hif_dev);
		ath9k_destoy_wmi(hif_dev->htc_handle->drv_priv);
		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;
	int ret;
	const struct firmware *fw;

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

	if (hif_dev->flags & HIF_USB_READY) {
		/* 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;
	} else {
		ath9k_hif_usb_dealloc_urbs(hif_dev);
		return -EIO;
	}

	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);
}