usb.c

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/*
 * Atheros CARL9170 driver
 *
 * USB - frontend
 *
 * Copyright 2008, Johannes Berg <[email protected]>
 * Copyright 2009, 2010, Christian Lamparter <[email protected]>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; see the file COPYING.  If not, see
 * http://www.gnu.org/licenses/.
 *
 * This file incorporates work covered by the following copyright and
 * permission notice:
 *    Copyright (c) 2007-2008 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/module.h>
#include <linux/slab.h>
#include <linux/usb.h>
#include <linux/firmware.h>
#include <linux/etherdevice.h>
#include <linux/device.h>
#include <net/mac80211.h>
#include "carl9170.h"
#include "cmd.h"
#include "hw.h"
#include "fwcmd.h"

MODULE_AUTHOR("Johannes Berg <[email protected]>");
MODULE_AUTHOR("Christian Lamparter <[email protected]>");
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Atheros AR9170 802.11n USB wireless");
MODULE_FIRMWARE(CARL9170FW_NAME);
MODULE_ALIAS("ar9170usb");
MODULE_ALIAS("arusb_lnx");

/*
 * Note:
 *
 * Always update our wiki's device list (located at:
 * http://wireless.kernel.org/en/users/Drivers/ar9170/devices ),
 * whenever you add a new device.
 */
static struct usb_device_id carl9170_usb_ids[] = {
    /* Atheros 9170 */
    { USB_DEVICE(0x0cf3, 0x9170) },
    /* Atheros TG121N */
    { USB_DEVICE(0x0cf3, 0x1001) },
    /* TP-Link TL-WN821N v2 */
    { USB_DEVICE(0x0cf3, 0x1002), .driver_info = CARL9170_WPS_BUTTON |
         CARL9170_ONE_LED },
    /* 3Com Dual Band 802.11n USB Adapter */
    { USB_DEVICE(0x0cf3, 0x1010) },
    /* H3C Dual Band 802.11n USB Adapter */
    { USB_DEVICE(0x0cf3, 0x1011) },
    /* Cace Airpcap NX */
    { USB_DEVICE(0xcace, 0x0300) },
    /* D-Link DWA 160 A1 */
    { USB_DEVICE(0x07d1, 0x3c10) },
    /* D-Link DWA 160 A2 */
    { USB_DEVICE(0x07d1, 0x3a09) },
    /* D-Link DWA 130 D */
    { USB_DEVICE(0x07d1, 0x3a0f) },
    /* Netgear WNA1000 */
    { USB_DEVICE(0x0846, 0x9040) },
    /* Netgear WNDA3100 (v1) */
    { USB_DEVICE(0x0846, 0x9010) },
    /* Netgear WN111 v2 */
    { USB_DEVICE(0x0846, 0x9001), .driver_info = CARL9170_ONE_LED },
    /* Zydas ZD1221 */
    { USB_DEVICE(0x0ace, 0x1221) },
    /* Proxim ORiNOCO 802.11n USB */
    { USB_DEVICE(0x1435, 0x0804) },
    /* WNC Generic 11n USB Dongle */
    { USB_DEVICE(0x1435, 0x0326) },
    /* ZyXEL NWD271N */
    { USB_DEVICE(0x0586, 0x3417) },
    /* Z-Com UB81 BG */
    { USB_DEVICE(0x0cde, 0x0023) },
    /* Z-Com UB82 ABG */
    { USB_DEVICE(0x0cde, 0x0026) },
    /* Sphairon Homelink 1202 */
    { USB_DEVICE(0x0cde, 0x0027) },
    /* Arcadyan WN7512 */
    { USB_DEVICE(0x083a, 0xf522) },
    /* Planex GWUS300 */
    { USB_DEVICE(0x2019, 0x5304) },
    /* IO-Data WNGDNUS2 */
    { USB_DEVICE(0x04bb, 0x093f) },
    /* NEC WL300NU-G */
    { USB_DEVICE(0x0409, 0x0249) },
    /* NEC WL300NU-AG */
    { USB_DEVICE(0x0409, 0x02b4) },
    /* AVM FRITZ!WLAN USB Stick N */
    { USB_DEVICE(0x057c, 0x8401) },
    /* AVM FRITZ!WLAN USB Stick N 2.4 */
    { USB_DEVICE(0x057c, 0x8402) },
    /* Qwest/Actiontec 802AIN Wireless N USB Network Adapter */
    { USB_DEVICE(0x1668, 0x1200) },
    /* Airlive X.USB a/b/g/n */
    { USB_DEVICE(0x1b75, 0x9170) },

    /* terminate */
    {}
};
MODULE_DEVICE_TABLE(usb, carl9170_usb_ids);

static void carl9170_usb_submit_data_urb(struct ar9170 *ar)
{
    struct urb *urb;
    int err;

    if (atomic_inc_return(&ar->tx_anch_urbs) > AR9170_NUM_TX_URBS)
        goto err_acc;

    urb = usb_get_from_anchor(&ar->tx_wait);
    if (!urb)
        goto err_acc;

    usb_anchor_urb(urb, &ar->tx_anch);

    err = usb_submit_urb(urb, GFP_ATOMIC);
    if (unlikely(err)) {
        if (net_ratelimit()) {
            dev_err(&ar->udev->dev, "tx submit failed (%d)\n",
                urb->status);
        }

        usb_unanchor_urb(urb);
        usb_anchor_urb(urb, &ar->tx_err);
    }

    usb_free_urb(urb);

    if (likely(err == 0))
        return;

err_acc:
    atomic_dec(&ar->tx_anch_urbs);
}

static void carl9170_usb_tx_data_complete(struct urb *urb)
{
    struct ar9170 *ar = usb_get_intfdata(usb_ifnum_to_if(urb->dev, 0));

    if (WARN_ON_ONCE(!ar)) {
        dev_kfree_skb_irq(urb->context);
        return;
    }

    atomic_dec(&ar->tx_anch_urbs);

    switch (urb->status) {
    /* everything is fine */
    case 0:
        carl9170_tx_callback(ar, (void *)urb->context);
        break;

    /* disconnect */
    case -ENOENT:
    case -ECONNRESET:
    case -ENODEV:
    case -ESHUTDOWN:
        /*
         * Defer the frame clean-up to the tasklet worker.
         * This is necessary, because carl9170_tx_drop
         * does not work in an irqsave context.
         */
        usb_anchor_urb(urb, &ar->tx_err);
        return;

    /* a random transmission error has occurred? */
    default:
        if (net_ratelimit()) {
            dev_err(&ar->udev->dev, "tx failed (%d)\n",
                urb->status);
        }

        usb_anchor_urb(urb, &ar->tx_err);
        break;
    }

    if (likely(IS_STARTED(ar)))
        carl9170_usb_submit_data_urb(ar);
}

static int carl9170_usb_submit_cmd_urb(struct ar9170 *ar)
{
    struct urb *urb;
    int err;

    if (atomic_inc_return(&ar->tx_cmd_urbs) != 1) {
        atomic_dec(&ar->tx_cmd_urbs);
        return 0;
    }

    urb = usb_get_from_anchor(&ar->tx_cmd);
    if (!urb) {
        atomic_dec(&ar->tx_cmd_urbs);
        return 0;
    }

    usb_anchor_urb(urb, &ar->tx_anch);
    err = usb_submit_urb(urb, GFP_ATOMIC);
    if (unlikely(err)) {
        usb_unanchor_urb(urb);
        atomic_dec(&ar->tx_cmd_urbs);
    }
    usb_free_urb(urb);

    return err;
}

static void carl9170_usb_cmd_complete(struct urb *urb)
{
    struct ar9170 *ar = urb->context;
    int err = 0;

    if (WARN_ON_ONCE(!ar))
        return;

    atomic_dec(&ar->tx_cmd_urbs);

    switch (urb->status) {
    /* everything is fine */
    case 0:
        break;

    /* disconnect */
    case -ENOENT:
    case -ECONNRESET:
    case -ENODEV:
    case -ESHUTDOWN:
        return;

    default:
        err = urb->status;
        break;
    }

    if (!IS_INITIALIZED(ar))
        return;

    if (err)
        dev_err(&ar->udev->dev, "submit cmd cb failed (%d).\n", err);

    err = carl9170_usb_submit_cmd_urb(ar);
    if (err)
        dev_err(&ar->udev->dev, "submit cmd failed (%d).\n", err);
}

static void carl9170_usb_rx_irq_complete(struct urb *urb)
{
    struct ar9170 *ar = urb->context;

    if (WARN_ON_ONCE(!ar))
        return;

    switch (urb->status) {
    /* everything is fine */
    case 0:
        break;

    /* disconnect */
    case -ENOENT:
    case -ECONNRESET:
    case -ENODEV:
    case -ESHUTDOWN:
        return;

    default:
        goto resubmit;
    }

    carl9170_handle_command_response(ar, urb->transfer_buffer,
                     urb->actual_length);

resubmit:
    usb_anchor_urb(urb, &ar->rx_anch);
    if (unlikely(usb_submit_urb(urb, GFP_ATOMIC)))
        usb_unanchor_urb(urb);
}

static int carl9170_usb_submit_rx_urb(struct ar9170 *ar, gfp_t gfp)
{
    struct urb *urb;
    int err = 0, runs = 0;

    while ((atomic_read(&ar->rx_anch_urbs) < AR9170_NUM_RX_URBS) &&
        (runs++ < AR9170_NUM_RX_URBS)) {
        err = -ENOSPC;
        urb = usb_get_from_anchor(&ar->rx_pool);
        if (urb) {
            usb_anchor_urb(urb, &ar->rx_anch);
            err = usb_submit_urb(urb, gfp);
            if (unlikely(err)) {
                usb_unanchor_urb(urb);
                usb_anchor_urb(urb, &ar->rx_pool);
            } else {
                atomic_dec(&ar->rx_pool_urbs);
                atomic_inc(&ar->rx_anch_urbs);
            }
            usb_free_urb(urb);
        }
    }

    return err;
}

static void carl9170_usb_rx_work(struct ar9170 *ar)
{
    struct urb *urb;
    int i;

    for (i = 0; i < AR9170_NUM_RX_URBS_POOL; i++) {
        urb = usb_get_from_anchor(&ar->rx_work);
        if (!urb)
            break;

        atomic_dec(&ar->rx_work_urbs);
        if (IS_INITIALIZED(ar)) {
            carl9170_rx(ar, urb->transfer_buffer,
                    urb->actual_length);
        }

        usb_anchor_urb(urb, &ar->rx_pool);
        atomic_inc(&ar->rx_pool_urbs);

        usb_free_urb(urb);

        carl9170_usb_submit_rx_urb(ar, GFP_ATOMIC);
    }
}

void carl9170_usb_handle_tx_err(struct ar9170 *ar)
{
    struct urb *urb;

    while ((urb = usb_get_from_anchor(&ar->tx_err))) {
        struct sk_buff *skb = (void *)urb->context;

        carl9170_tx_drop(ar, skb);
        carl9170_tx_callback(ar, skb);
        usb_free_urb(urb);
    }
}

static void carl9170_usb_tasklet(unsigned long data)
{
    struct ar9170 *ar = (struct ar9170 *) data;

    if (!IS_INITIALIZED(ar))
        return;

    carl9170_usb_rx_work(ar);

    /*
     * Strictly speaking: The tx scheduler is not part of the USB system.
     * But the rx worker returns frames back to the mac80211-stack and
     * this is the _perfect_ place to generate the next transmissions.
     */
    if (IS_STARTED(ar))
        carl9170_tx_scheduler(ar);
}

static void carl9170_usb_rx_complete(struct urb *urb)
{
    struct ar9170 *ar = (struct ar9170 *)urb->context;
    int err;

    if (WARN_ON_ONCE(!ar))
        return;

    atomic_dec(&ar->rx_anch_urbs);

    switch (urb->status) {
    case 0:
        /* rx path */
        usb_anchor_urb(urb, &ar->rx_work);
        atomic_inc(&ar->rx_work_urbs);
        break;

    case -ENOENT:
    case -ECONNRESET:
    case -ENODEV:
    case -ESHUTDOWN:
        /* handle disconnect events*/
        return;

    default:
        /* handle all other errors */
        usb_anchor_urb(urb, &ar->rx_pool);
        atomic_inc(&ar->rx_pool_urbs);
        break;
    }

    err = carl9170_usb_submit_rx_urb(ar, GFP_ATOMIC);
    if (unlikely(err)) {
        /*
         * usb_submit_rx_urb reported a problem.
         * In case this is due to a rx buffer shortage,
         * elevate the tasklet worker priority to
         * the highest available level.
         */
        tasklet_hi_schedule(&ar->usb_tasklet);

        if (atomic_read(&ar->rx_anch_urbs) == 0) {
            /*
             * The system is too slow to cope with
             * the enormous workload. We have simply
             * run out of active rx urbs and this
             * unfortunately leads to an unpredictable
             * device.
             */

            ieee80211_queue_work(ar->hw, &ar->ping_work);
        }
    } else {
        /*
         * Using anything less than _high_ priority absolutely
         * kills the rx performance my UP-System...
         */
        tasklet_hi_schedule(&ar->usb_tasklet);
    }
}

static struct urb *carl9170_usb_alloc_rx_urb(struct ar9170 *ar, gfp_t gfp)
{
    struct urb *urb;
    void *buf;

    buf = kmalloc(ar->fw.rx_size, gfp);
    if (!buf)
        return NULL;

    urb = usb_alloc_urb(0, gfp);
    if (!urb) {
        kfree(buf);
        return NULL;
    }

    usb_fill_bulk_urb(urb, ar->udev, usb_rcvbulkpipe(ar->udev,
              AR9170_USB_EP_RX), buf, ar->fw.rx_size,
              carl9170_usb_rx_complete, ar);

    urb->transfer_flags |= URB_FREE_BUFFER;

    return urb;
}

static int carl9170_usb_send_rx_irq_urb(struct ar9170 *ar)
{
    struct urb *urb = NULL;
    void *ibuf;
    int err = -ENOMEM;

    urb = usb_alloc_urb(0, GFP_KERNEL);
    if (!urb)
        goto out;

    ibuf = kmalloc(AR9170_USB_EP_CTRL_MAX, GFP_KERNEL);
    if (!ibuf)
        goto out;

    usb_fill_int_urb(urb, ar->udev, usb_rcvintpipe(ar->udev,
             AR9170_USB_EP_IRQ), ibuf, AR9170_USB_EP_CTRL_MAX,
             carl9170_usb_rx_irq_complete, ar, 1);

    urb->transfer_flags |= URB_FREE_BUFFER;

    usb_anchor_urb(urb, &ar->rx_anch);
    err = usb_submit_urb(urb, GFP_KERNEL);
    if (err)
        usb_unanchor_urb(urb);

out:
    usb_free_urb(urb);
    return err;
}

static int carl9170_usb_init_rx_bulk_urbs(struct ar9170 *ar)
{
    struct urb *urb;
    int i, err = -EINVAL;

    /*
     * The driver actively maintains a second shadow
     * pool for inactive, but fully-prepared rx urbs.
     *
     * The pool should help the driver to master huge
     * workload spikes without running the risk of
     * undersupplying the hardware or wasting time by
     * processing rx data (streams) inside the urb
     * completion (hardirq context).
     */
    for (i = 0; i < AR9170_NUM_RX_URBS_POOL; i++) {
        urb = carl9170_usb_alloc_rx_urb(ar, GFP_KERNEL);
        if (!urb) {
            err = -ENOMEM;
            goto err_out;
        }

        usb_anchor_urb(urb, &ar->rx_pool);
        atomic_inc(&ar->rx_pool_urbs);
        usb_free_urb(urb);
    }

    err = carl9170_usb_submit_rx_urb(ar, GFP_KERNEL);
    if (err)
        goto err_out;

    /* the device now waiting for the firmware. */
    carl9170_set_state_when(ar, CARL9170_STOPPED, CARL9170_IDLE);
    return 0;

err_out:

    usb_scuttle_anchored_urbs(&ar->rx_pool);
    usb_scuttle_anchored_urbs(&ar->rx_work);
    usb_kill_anchored_urbs(&ar->rx_anch);
    return err;
}

static int carl9170_usb_flush(struct ar9170 *ar)
{
    struct urb *urb;
    int ret, err = 0;

    while ((urb = usb_get_from_anchor(&ar->tx_wait))) {
        struct sk_buff *skb = (void *)urb->context;
        carl9170_tx_drop(ar, skb);
        carl9170_tx_callback(ar, skb);
        usb_free_urb(urb);
    }

    ret = usb_wait_anchor_empty_timeout(&ar->tx_cmd, 1000);
    if (ret == 0)
        err = -ETIMEDOUT;

    /* lets wait a while until the tx - queues are dried out */
    ret = usb_wait_anchor_empty_timeout(&ar->tx_anch, 1000);
    if (ret == 0)
        err = -ETIMEDOUT;

    usb_kill_anchored_urbs(&ar->tx_anch);
    carl9170_usb_handle_tx_err(ar);

    return err;
}

static void carl9170_usb_cancel_urbs(struct ar9170 *ar)
{
    int err;

    carl9170_set_state(ar, CARL9170_UNKNOWN_STATE);

    err = carl9170_usb_flush(ar);
    if (err)
        dev_err(&ar->udev->dev, "stuck tx urbs!\n");

    usb_poison_anchored_urbs(&ar->tx_anch);
    carl9170_usb_handle_tx_err(ar);
    usb_poison_anchored_urbs(&ar->rx_anch);

    tasklet_kill(&ar->usb_tasklet);

    usb_scuttle_anchored_urbs(&ar->rx_work);
    usb_scuttle_anchored_urbs(&ar->rx_pool);
    usb_scuttle_anchored_urbs(&ar->tx_cmd);
}

int __carl9170_exec_cmd(struct ar9170 *ar, struct carl9170_cmd *cmd,
            const bool free_buf)
{
    struct urb *urb;
    int err = 0;

    if (!IS_INITIALIZED(ar)) {
        err = -EPERM;
        goto err_free;
    }

    if (WARN_ON(cmd->hdr.len > CARL9170_MAX_CMD_LEN - 4)) {
        err = -EINVAL;
        goto err_free;
    }

    urb = usb_alloc_urb(0, GFP_ATOMIC);
    if (!urb) {
        err = -ENOMEM;
        goto err_free;
    }

    usb_fill_int_urb(urb, ar->udev, usb_sndintpipe(ar->udev,
        AR9170_USB_EP_CMD), cmd, cmd->hdr.len + 4,
        carl9170_usb_cmd_complete, ar, 1);

    if (free_buf)
        urb->transfer_flags |= URB_FREE_BUFFER;

    usb_anchor_urb(urb, &ar->tx_cmd);
    usb_free_urb(urb);

    return carl9170_usb_submit_cmd_urb(ar);

err_free:
    if (free_buf)
        kfree(cmd);

    return err;
}

int carl9170_exec_cmd(struct ar9170 *ar, const enum carl9170_cmd_oids cmd,
    unsigned int plen, void *payload, unsigned int outlen, void *out)
{
    int err = -ENOMEM;

    if (!IS_ACCEPTING_CMD(ar))
        return -EIO;

    if (!(cmd & CARL9170_CMD_ASYNC_FLAG))
        might_sleep();

    ar->cmd.hdr.len = plen;
    ar->cmd.hdr.cmd = cmd;
    /* writing multiple regs fills this buffer already */
    if (plen && payload != (u8 *)(ar->cmd.data))
        memcpy(ar->cmd.data, payload, plen);

    spin_lock_bh(&ar->cmd_lock);
    ar->readbuf = (u8 *)out;
    ar->readlen = outlen;
    spin_unlock_bh(&ar->cmd_lock);

    err = __carl9170_exec_cmd(ar, &ar->cmd, false);

    if (!(cmd & CARL9170_CMD_ASYNC_FLAG)) {
        err = wait_for_completion_timeout(&ar->cmd_wait, HZ);
        if (err == 0) {
            err = -ETIMEDOUT;
            goto err_unbuf;
        }

        if (ar->readlen != outlen) {
            err = -EMSGSIZE;
            goto err_unbuf;
        }
    }

    return 0;

err_unbuf:
    /* Maybe the device was removed in the moment we were waiting? */
    if (IS_STARTED(ar)) {
        dev_err(&ar->udev->dev, "no command feedback "
            "received (%d).\n", err);

        /* provide some maybe useful debug information */
        print_hex_dump_bytes("carl9170 cmd: ", DUMP_PREFIX_NONE,
                     &ar->cmd, plen + 4);

        carl9170_restart(ar, CARL9170_RR_COMMAND_TIMEOUT);
    }

    /* invalidate to avoid completing the next command prematurely */
    spin_lock_bh(&ar->cmd_lock);
    ar->readbuf = NULL;
    ar->readlen = 0;
    spin_unlock_bh(&ar->cmd_lock);

    return err;
}

void carl9170_usb_tx(struct ar9170 *ar, struct sk_buff *skb)
{
    struct urb *urb;
    struct ar9170_stream *tx_stream;
    void *data;
    unsigned int len;

    if (!IS_STARTED(ar))
        goto err_drop;

    urb = usb_alloc_urb(0, GFP_ATOMIC);
    if (!urb)
        goto err_drop;

    if (ar->fw.tx_stream) {
        tx_stream = (void *) (skb->data - sizeof(*tx_stream));

        len = skb->len + sizeof(*tx_stream);
        tx_stream->length = cpu_to_le16(len);
        tx_stream->tag = cpu_to_le16(AR9170_TX_STREAM_TAG);
        data = tx_stream;
    } else {
        data = skb->data;
        len = skb->len;
    }

    usb_fill_bulk_urb(urb, ar->udev, usb_sndbulkpipe(ar->udev,
        AR9170_USB_EP_TX), data, len,
        carl9170_usb_tx_data_complete, skb);

    urb->transfer_flags |= URB_ZERO_PACKET;

    usb_anchor_urb(urb, &ar->tx_wait);

    usb_free_urb(urb);

    carl9170_usb_submit_data_urb(ar);
    return;

err_drop:
    carl9170_tx_drop(ar, skb);
    carl9170_tx_callback(ar, skb);
}

static void carl9170_release_firmware(struct ar9170 *ar)
{
    if (ar->fw.fw) {
        release_firmware(ar->fw.fw);
        memset(&ar->fw, 0, sizeof(ar->fw));
    }
}

void carl9170_usb_stop(struct ar9170 *ar)
{
    int ret;

    carl9170_set_state_when(ar, CARL9170_IDLE, CARL9170_STOPPED);

    ret = carl9170_usb_flush(ar);
    if (ret)
        dev_err(&ar->udev->dev, "kill pending tx urbs.\n");

    usb_poison_anchored_urbs(&ar->tx_anch);
    carl9170_usb_handle_tx_err(ar);

    /* kill any pending command */
    spin_lock_bh(&ar->cmd_lock);
    ar->readlen = 0;
    spin_unlock_bh(&ar->cmd_lock);
    complete_all(&ar->cmd_wait);

    /* This is required to prevent an early completion on _start */
    INIT_COMPLETION(ar->cmd_wait);

    /*
     * Note:
     * So far we freed all tx urbs, but we won't dare to touch any rx urbs.
     * Else we would end up with a unresponsive device...
     */
}

int carl9170_usb_open(struct ar9170 *ar)
{
    usb_unpoison_anchored_urbs(&ar->tx_anch);

    carl9170_set_state_when(ar, CARL9170_STOPPED, CARL9170_IDLE);
    return 0;
}

static int carl9170_usb_load_firmware(struct ar9170 *ar)
{
    const u8 *data;
    u8 *buf;
    unsigned int transfer;
    size_t len;
    u32 addr;
    int err = 0;

    buf = kmalloc(4096, GFP_KERNEL);
    if (!buf) {
        err = -ENOMEM;
        goto err_out;
    }

    data = ar->fw.fw->data;
    len = ar->fw.fw->size;
    addr = ar->fw.address;

    /* this removes the miniboot image */
    data += ar->fw.offset;
    len -= ar->fw.offset;

    while (len) {
        transfer = min_t(unsigned int, len, 4096u);
        memcpy(buf, data, transfer);

        err = usb_control_msg(ar->udev, usb_sndctrlpipe(ar->udev, 0),
                      0x30 /* FW DL */, 0x40 | USB_DIR_OUT,
                      addr >> 8, 0, buf, transfer, 100);

        if (err < 0) {
            kfree(buf);
            goto err_out;
        }

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

    err = usb_control_msg(ar->udev, usb_sndctrlpipe(ar->udev, 0),
                  0x31 /* FW DL COMPLETE */,
                  0x40 | USB_DIR_OUT, 0, 0, NULL, 0, 200);

    if (wait_for_completion_timeout(&ar->fw_boot_wait, HZ) == 0) {
        err = -ETIMEDOUT;
        goto err_out;
    }

    err = carl9170_echo_test(ar, 0x4a110123);
    if (err)
        goto err_out;

    /* now, start the command response counter */
    ar->cmd_seq = -1;

    return 0;

err_out:
    dev_err(&ar->udev->dev, "firmware upload failed (%d).\n", err);
    return err;
}

int carl9170_usb_restart(struct ar9170 *ar)
{
    int err = 0;

    if (ar->intf->condition != USB_INTERFACE_BOUND)
        return 0;

    /*
     * Disable the command response sequence counter check.
     * We already know that the device/firmware is in a bad state.
     * So, no extra points are awarded to anyone who reminds the
     * driver about that.
     */
    ar->cmd_seq = -2;

    err = carl9170_reboot(ar);

    carl9170_usb_stop(ar);

    if (err)
        goto err_out;

    tasklet_schedule(&ar->usb_tasklet);

    /* The reboot procedure can take quite a while to complete. */
    msleep(1100);

    err = carl9170_usb_open(ar);
    if (err)
        goto err_out;

    err = carl9170_usb_load_firmware(ar);
    if (err)
        goto err_out;

    return 0;

err_out:
    carl9170_usb_cancel_urbs(ar);
    return err;
}

void carl9170_usb_reset(struct ar9170 *ar)
{
    /*
     * This is the last resort to get the device going again
     * without any *user replugging action*.
     *
     * But there is a catch: usb_reset really is like a physical
     * *reconnect*. The mac80211 state will be lost in the process.
     * Therefore a userspace application, which is monitoring
     * the link must step in.
     */
    carl9170_usb_cancel_urbs(ar);

    carl9170_usb_stop(ar);

    usb_queue_reset_device(ar->intf);
}

static int carl9170_usb_init_device(struct ar9170 *ar)
{
    int err;

    /*
     * The carl9170 firmware let's the driver know when it's
     * ready for action. But we have to be prepared to gracefully
     * handle all spurious [flushed] messages after each (re-)boot.
     * Thus the command response counter remains disabled until it
     * can be safely synchronized.
     */
    ar->cmd_seq = -2;

    err = carl9170_usb_send_rx_irq_urb(ar);
    if (err)
        goto err_out;

    err = carl9170_usb_init_rx_bulk_urbs(ar);
    if (err)
        goto err_unrx;

    err = carl9170_usb_open(ar);
    if (err)
        goto err_unrx;

    mutex_lock(&ar->mutex);
    err = carl9170_usb_load_firmware(ar);
    mutex_unlock(&ar->mutex);
    if (err)
        goto err_stop;

    return 0;

err_stop:
    carl9170_usb_stop(ar);

err_unrx:
    carl9170_usb_cancel_urbs(ar);

err_out:
    return err;
}

static void carl9170_usb_firmware_failed(struct ar9170 *ar)
{
    struct device *parent = ar->udev->dev.parent;
    struct usb_device *udev;

    /*
     * Store a copy of the usb_device pointer locally.
     * This is because device_release_driver initiates
     * carl9170_usb_disconnect, which in turn frees our
     * driver context (ar).
     */
    udev = ar->udev;

    complete(&ar->fw_load_wait);

    /* unbind anything failed */
    if (parent)
        device_lock(parent);

    device_release_driver(&udev->dev);
    if (parent)
        device_unlock(parent);

    usb_put_dev(udev);
}

static void carl9170_usb_firmware_finish(struct ar9170 *ar)
{
    int err;

    err = carl9170_parse_firmware(ar);
    if (err)
        goto err_freefw;

    err = carl9170_usb_init_device(ar);
    if (err)
        goto err_freefw;

    err = carl9170_register(ar);

    carl9170_usb_stop(ar);
    if (err)
        goto err_unrx;

    complete(&ar->fw_load_wait);
    usb_put_dev(ar->udev);
    return;

err_unrx:
    carl9170_usb_cancel_urbs(ar);

err_freefw:
    carl9170_release_firmware(ar);
    carl9170_usb_firmware_failed(ar);
}

static void carl9170_usb_firmware_step2(const struct firmware *fw,
                    void *context)
{
    struct ar9170 *ar = context;

    if (fw) {
        ar->fw.fw = fw;
        carl9170_usb_firmware_finish(ar);
        return;
    }

    dev_err(&ar->udev->dev, "firmware not found.\n");
    carl9170_usb_firmware_failed(ar);
}

static int carl9170_usb_probe(struct usb_interface *intf,
                  const struct usb_device_id *id)
{
    struct ar9170 *ar;
    struct usb_device *udev;
    int err;

    err = usb_reset_device(interface_to_usbdev(intf));
    if (err)
        return err;

    ar = carl9170_alloc(sizeof(*ar));
    if (IS_ERR(ar))
        return PTR_ERR(ar);

    udev = interface_to_usbdev(intf);
    usb_get_dev(udev);
    ar->udev = udev;
    ar->intf = intf;
    ar->features = id->driver_info;

    usb_set_intfdata(intf, ar);
    SET_IEEE80211_DEV(ar->hw, &intf->dev);

    init_usb_anchor(&ar->rx_anch);
    init_usb_anchor(&ar->rx_pool);
    init_usb_anchor(&ar->rx_work);
    init_usb_anchor(&ar->tx_wait);
    init_usb_anchor(&ar->tx_anch);
    init_usb_anchor(&ar->tx_cmd);
    init_usb_anchor(&ar->tx_err);
    init_completion(&ar->cmd_wait);
    init_completion(&ar->fw_boot_wait);
    init_completion(&ar->fw_load_wait);
    tasklet_init(&ar->usb_tasklet, carl9170_usb_tasklet,
             (unsigned long)ar);

    atomic_set(&ar->tx_cmd_urbs, 0);
    atomic_set(&ar->tx_anch_urbs, 0);
    atomic_set(&ar->rx_work_urbs, 0);
    atomic_set(&ar->rx_anch_urbs, 0);
    atomic_set(&ar->rx_pool_urbs, 0);

    usb_get_dev(ar->udev);

    carl9170_set_state(ar, CARL9170_STOPPED);

    return request_firmware_nowait(THIS_MODULE, 1, CARL9170FW_NAME,
        &ar->udev->dev, GFP_KERNEL, ar, carl9170_usb_firmware_step2);
}

static void carl9170_usb_disconnect(struct usb_interface *intf)
{
    struct ar9170 *ar = usb_get_intfdata(intf);
    struct usb_device *udev;

    if (WARN_ON(!ar))
        return;

    udev = ar->udev;
    wait_for_completion(&ar->fw_load_wait);

    if (IS_INITIALIZED(ar)) {
        carl9170_reboot(ar);
        carl9170_usb_stop(ar);
    }

    carl9170_usb_cancel_urbs(ar);
    carl9170_unregister(ar);

    usb_set_intfdata(intf, NULL);

    carl9170_release_firmware(ar);
    carl9170_free(ar);
    usb_put_dev(udev);
}

#ifdef CONFIG_PM
static int carl9170_usb_suspend(struct usb_interface *intf,
                pm_message_t message)
{
    struct ar9170 *ar = usb_get_intfdata(intf);

    if (!ar)
        return -ENODEV;

    carl9170_usb_cancel_urbs(ar);

    return 0;
}

static int carl9170_usb_resume(struct usb_interface *intf)
{
    struct ar9170 *ar = usb_get_intfdata(intf);
    int err;

    if (!ar)
        return -ENODEV;

    usb_unpoison_anchored_urbs(&ar->rx_anch);
    carl9170_set_state(ar, CARL9170_STOPPED);

    /*
     * The USB documentation demands that [for suspend] all traffic
     * to and from the device has to stop. This would be fine, but
     * there's a catch: the device[usb phy] does not come back.
     *
     * Upon resume the firmware will "kill" itself and the
     * boot-code sorts out the magic voodoo.
     * Not very nice, but there's not much what could go wrong.
     */
    msleep(1100);

    err = carl9170_usb_init_device(ar);
    if (err)
        goto err_unrx;

    return 0;

err_unrx:
    carl9170_usb_cancel_urbs(ar);

    return err;
}
#endif /* CONFIG_PM */

static struct usb_driver carl9170_driver = {
    .name = KBUILD_MODNAME,
    .probe = carl9170_usb_probe,
    .disconnect = carl9170_usb_disconnect,
    .id_table = carl9170_usb_ids,
    .soft_unbind = 1,
#ifdef CONFIG_PM
    .suspend = carl9170_usb_suspend,
    .resume = carl9170_usb_resume,
    .reset_resume = carl9170_usb_resume,
#endif /* CONFIG_PM */
    .disable_hub_initiated_lpm = 1,
};

module_usb_driver(carl9170_driver);