rt2x00usb.c

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/*
    Copyright (C) 2010 Willow Garage <http://www.willowgarage.com>
    Copyright (C) 2004 - 2010 Ivo van Doorn <[email protected]>
    <http://rt2x00.serialmonkey.com>

    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; if not, write to the
    Free Software Foundation, Inc.,
    59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

/*
    Module: rt2x00usb
    Abstract: rt2x00 generic usb device routines.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/usb.h>
#include <linux/bug.h>

#include "rt2x00.h"
#include "rt2x00usb.h"

/*
 * Interfacing with the HW.
 */
int rt2x00usb_vendor_request(struct rt2x00_dev *rt2x00dev,
                 const u8 request, const u8 requesttype,
                 const u16 offset, const u16 value,
                 void *buffer, const u16 buffer_length,
                 const int timeout)
{
    struct usb_device *usb_dev = to_usb_device_intf(rt2x00dev->dev);
    int status;
    unsigned int i;
    unsigned int pipe =
        (requesttype == USB_VENDOR_REQUEST_IN) ?
        usb_rcvctrlpipe(usb_dev, 0) : usb_sndctrlpipe(usb_dev, 0);

    if (!test_bit(DEVICE_STATE_PRESENT, &rt2x00dev->flags))
        return -ENODEV;

    for (i = 0; i < REGISTER_BUSY_COUNT; i++) {
        status = usb_control_msg(usb_dev, pipe, request, requesttype,
                     value, offset, buffer, buffer_length,
                     timeout);
        if (status >= 0)
            return 0;

        /*
         * Check for errors
         * -ENODEV: Device has disappeared, no point continuing.
         * All other errors: Try again.
         */
        else if (status == -ENODEV) {
            clear_bit(DEVICE_STATE_PRESENT, &rt2x00dev->flags);
            break;
        }
    }

    ERROR(rt2x00dev,
          "Vendor Request 0x%02x failed for offset 0x%04x with error %d.\n",
          request, offset, status);

    return status;
}
EXPORT_SYMBOL_GPL(rt2x00usb_vendor_request);

int rt2x00usb_vendor_req_buff_lock(struct rt2x00_dev *rt2x00dev,
                   const u8 request, const u8 requesttype,
                   const u16 offset, void *buffer,
                   const u16 buffer_length, const int timeout)
{
    int status;

    BUG_ON(!mutex_is_locked(&rt2x00dev->csr_mutex));

    /*
     * Check for Cache availability.
     */
    if (unlikely(!rt2x00dev->csr.cache || buffer_length > CSR_CACHE_SIZE)) {
        ERROR(rt2x00dev, "CSR cache not available.\n");
        return -ENOMEM;
    }

    if (requesttype == USB_VENDOR_REQUEST_OUT)
        memcpy(rt2x00dev->csr.cache, buffer, buffer_length);

    status = rt2x00usb_vendor_request(rt2x00dev, request, requesttype,
                      offset, 0, rt2x00dev->csr.cache,
                      buffer_length, timeout);

    if (!status && requesttype == USB_VENDOR_REQUEST_IN)
        memcpy(buffer, rt2x00dev->csr.cache, buffer_length);

    return status;
}
EXPORT_SYMBOL_GPL(rt2x00usb_vendor_req_buff_lock);

int rt2x00usb_vendor_request_buff(struct rt2x00_dev *rt2x00dev,
                  const u8 request, const u8 requesttype,
                  const u16 offset, void *buffer,
                  const u16 buffer_length, const int timeout)
{
    int status = 0;
    unsigned char *tb;
    u16 off, len, bsize;

    mutex_lock(&rt2x00dev->csr_mutex);

    tb  = (char *)buffer;
    off = offset;
    len = buffer_length;
    while (len && !status) {
        bsize = min_t(u16, CSR_CACHE_SIZE, len);
        status = rt2x00usb_vendor_req_buff_lock(rt2x00dev, request,
                            requesttype, off, tb,
                            bsize, timeout);

        tb  += bsize;
        len -= bsize;
        off += bsize;
    }

    mutex_unlock(&rt2x00dev->csr_mutex);

    return status;
}
EXPORT_SYMBOL_GPL(rt2x00usb_vendor_request_buff);

int rt2x00usb_regbusy_read(struct rt2x00_dev *rt2x00dev,
               const unsigned int offset,
               const struct rt2x00_field32 field,
               u32 *reg)
{
    unsigned int i;

    if (!test_bit(DEVICE_STATE_PRESENT, &rt2x00dev->flags))
        return -ENODEV;

    for (i = 0; i < REGISTER_BUSY_COUNT; i++) {
        rt2x00usb_register_read_lock(rt2x00dev, offset, reg);
        if (!rt2x00_get_field32(*reg, field))
            return 1;
        udelay(REGISTER_BUSY_DELAY);
    }

    ERROR(rt2x00dev, "Indirect register access failed: "
          "offset=0x%.08x, value=0x%.08x\n", offset, *reg);
    *reg = ~0;

    return 0;
}
EXPORT_SYMBOL_GPL(rt2x00usb_regbusy_read);


struct rt2x00_async_read_data {
    __le32 reg;
    struct usb_ctrlrequest cr;
    struct rt2x00_dev *rt2x00dev;
    bool (*callback)(struct rt2x00_dev *, int, u32);
};

static void rt2x00usb_register_read_async_cb(struct urb *urb)
{
    struct rt2x00_async_read_data *rd = urb->context;
    if (rd->callback(rd->rt2x00dev, urb->status, le32_to_cpu(rd->reg))) {
        if (usb_submit_urb(urb, GFP_ATOMIC) < 0)
            kfree(rd);
    } else
        kfree(rd);
}

void rt2x00usb_register_read_async(struct rt2x00_dev *rt2x00dev,
                   const unsigned int offset,
                   bool (*callback)(struct rt2x00_dev*, int, u32))
{
    struct usb_device *usb_dev = to_usb_device_intf(rt2x00dev->dev);
    struct urb *urb;
    struct rt2x00_async_read_data *rd;

    rd = kmalloc(sizeof(*rd), GFP_ATOMIC);
    if (!rd)
        return;

    urb = usb_alloc_urb(0, GFP_ATOMIC);
    if (!urb) {
        kfree(rd);
        return;
    }

    rd->rt2x00dev = rt2x00dev;
    rd->callback = callback;
    rd->cr.bRequestType = USB_VENDOR_REQUEST_IN;
    rd->cr.bRequest = USB_MULTI_READ;
    rd->cr.wValue = 0;
    rd->cr.wIndex = cpu_to_le16(offset);
    rd->cr.wLength = cpu_to_le16(sizeof(u32));

    usb_fill_control_urb(urb, usb_dev, usb_rcvctrlpipe(usb_dev, 0),
                 (unsigned char *)(&rd->cr), &rd->reg, sizeof(rd->reg),
                 rt2x00usb_register_read_async_cb, rd);
    if (usb_submit_urb(urb, GFP_ATOMIC) < 0)
        kfree(rd);
    usb_free_urb(urb);
}
EXPORT_SYMBOL_GPL(rt2x00usb_register_read_async);

/*
 * TX data handlers.
 */
static void rt2x00usb_work_txdone_entry(struct queue_entry *entry)
{
    /*
     * If the transfer to hardware succeeded, it does not mean the
     * frame was send out correctly. It only means the frame
     * was successfully pushed to the hardware, we have no
     * way to determine the transmission status right now.
     * (Only indirectly by looking at the failed TX counters
     * in the register).
     */
    if (test_bit(ENTRY_DATA_IO_FAILED, &entry->flags))
        rt2x00lib_txdone_noinfo(entry, TXDONE_FAILURE);
    else
        rt2x00lib_txdone_noinfo(entry, TXDONE_UNKNOWN);
}

static void rt2x00usb_work_txdone(struct work_struct *work)
{
    struct rt2x00_dev *rt2x00dev =
        container_of(work, struct rt2x00_dev, txdone_work);
    struct data_queue *queue;
    struct queue_entry *entry;

    tx_queue_for_each(rt2x00dev, queue) {
        while (!rt2x00queue_empty(queue)) {
            entry = rt2x00queue_get_entry(queue, Q_INDEX_DONE);

            if (test_bit(ENTRY_OWNER_DEVICE_DATA, &entry->flags) ||
                !test_bit(ENTRY_DATA_STATUS_PENDING, &entry->flags))
                break;

            rt2x00usb_work_txdone_entry(entry);
        }
    }
}

static void rt2x00usb_interrupt_txdone(struct urb *urb)
{
    struct queue_entry *entry = (struct queue_entry *)urb->context;
    struct rt2x00_dev *rt2x00dev = entry->queue->rt2x00dev;

    if (!test_bit(ENTRY_OWNER_DEVICE_DATA, &entry->flags))
        return;
    /*
     * Check if the frame was correctly uploaded
     */
    if (urb->status)
        set_bit(ENTRY_DATA_IO_FAILED, &entry->flags);
    /*
     * Report the frame as DMA done
     */
    rt2x00lib_dmadone(entry);

    if (rt2x00dev->ops->lib->tx_dma_done)
        rt2x00dev->ops->lib->tx_dma_done(entry);
    /*
     * Schedule the delayed work for reading the TX status
     * from the device.
     */
    if (!test_bit(REQUIRE_TXSTATUS_FIFO, &rt2x00dev->cap_flags) ||
        !kfifo_is_empty(&rt2x00dev->txstatus_fifo))
        queue_work(rt2x00dev->workqueue, &rt2x00dev->txdone_work);
}

static bool rt2x00usb_kick_tx_entry(struct queue_entry *entry)
{
    struct rt2x00_dev *rt2x00dev = entry->queue->rt2x00dev;
    struct usb_device *usb_dev = to_usb_device_intf(rt2x00dev->dev);
    struct queue_entry_priv_usb *entry_priv = entry->priv_data;
    u32 length;
    int status;

    if (!test_and_clear_bit(ENTRY_DATA_PENDING, &entry->flags) ||
        test_bit(ENTRY_DATA_STATUS_PENDING, &entry->flags))
        return false;

    /*
     * USB devices require certain padding at the end of each frame
     * and urb. Those paddings are not included in skbs. Pass entry
     * to the driver to determine what the overall length should be.
     */
    length = rt2x00dev->ops->lib->get_tx_data_len(entry);

    status = skb_padto(entry->skb, length);
    if (unlikely(status)) {
        /* TODO: report something more appropriate than IO_FAILED. */
        WARNING(rt2x00dev, "TX SKB padding error, out of memory\n");
        set_bit(ENTRY_DATA_IO_FAILED, &entry->flags);
        rt2x00lib_dmadone(entry);

        return false;
    }

    usb_fill_bulk_urb(entry_priv->urb, usb_dev,
              usb_sndbulkpipe(usb_dev, entry->queue->usb_endpoint),
              entry->skb->data, length,
              rt2x00usb_interrupt_txdone, entry);

    status = usb_submit_urb(entry_priv->urb, GFP_ATOMIC);
    if (status) {
        if (status == -ENODEV)
            clear_bit(DEVICE_STATE_PRESENT, &rt2x00dev->flags);
        set_bit(ENTRY_DATA_IO_FAILED, &entry->flags);
        rt2x00lib_dmadone(entry);
    }

    return false;
}

/*
 * RX data handlers.
 */
static void rt2x00usb_work_rxdone(struct work_struct *work)
{
    struct rt2x00_dev *rt2x00dev =
        container_of(work, struct rt2x00_dev, rxdone_work);
    struct queue_entry *entry;
    struct skb_frame_desc *skbdesc;
    u8 rxd[32];

    while (!rt2x00queue_empty(rt2x00dev->rx)) {
        entry = rt2x00queue_get_entry(rt2x00dev->rx, Q_INDEX_DONE);

        if (test_bit(ENTRY_OWNER_DEVICE_DATA, &entry->flags) ||
            !test_bit(ENTRY_DATA_STATUS_PENDING, &entry->flags))
            break;

        /*
         * Fill in desc fields of the skb descriptor
         */
        skbdesc = get_skb_frame_desc(entry->skb);
        skbdesc->desc = rxd;
        skbdesc->desc_len = entry->queue->desc_size;

        /*
         * Send the frame to rt2x00lib for further processing.
         */
        rt2x00lib_rxdone(entry, GFP_KERNEL);
    }
}

static void rt2x00usb_interrupt_rxdone(struct urb *urb)
{
    struct queue_entry *entry = (struct queue_entry *)urb->context;
    struct rt2x00_dev *rt2x00dev = entry->queue->rt2x00dev;

    if (!test_and_clear_bit(ENTRY_OWNER_DEVICE_DATA, &entry->flags))
        return;

    /*
     * Report the frame as DMA done
     */
    rt2x00lib_dmadone(entry);

    /*
     * Check if the received data is simply too small
     * to be actually valid, or if the urb is signaling
     * a problem.
     */
    if (urb->actual_length < entry->queue->desc_size || urb->status)
        set_bit(ENTRY_DATA_IO_FAILED, &entry->flags);

    /*
     * Schedule the delayed work for reading the RX status
     * from the device.
     */
    queue_work(rt2x00dev->workqueue, &rt2x00dev->rxdone_work);
}

static bool rt2x00usb_kick_rx_entry(struct queue_entry *entry)
{
    struct rt2x00_dev *rt2x00dev = entry->queue->rt2x00dev;
    struct usb_device *usb_dev = to_usb_device_intf(rt2x00dev->dev);
    struct queue_entry_priv_usb *entry_priv = entry->priv_data;
    int status;

    if (test_and_set_bit(ENTRY_OWNER_DEVICE_DATA, &entry->flags) ||
        test_bit(ENTRY_DATA_STATUS_PENDING, &entry->flags))
        return false;

    rt2x00lib_dmastart(entry);

    usb_fill_bulk_urb(entry_priv->urb, usb_dev,
              usb_rcvbulkpipe(usb_dev, entry->queue->usb_endpoint),
              entry->skb->data, entry->skb->len,
              rt2x00usb_interrupt_rxdone, entry);

    status = usb_submit_urb(entry_priv->urb, GFP_ATOMIC);
    if (status) {
        if (status == -ENODEV)
            clear_bit(DEVICE_STATE_PRESENT, &rt2x00dev->flags);
        set_bit(ENTRY_DATA_IO_FAILED, &entry->flags);
        rt2x00lib_dmadone(entry);
    }

    return false;
}

void rt2x00usb_kick_queue(struct data_queue *queue)
{
    switch (queue->qid) {
    case QID_AC_VO:
    case QID_AC_VI:
    case QID_AC_BE:
    case QID_AC_BK:
        if (!rt2x00queue_empty(queue))
            rt2x00queue_for_each_entry(queue, Q_INDEX_DONE, Q_INDEX,
                           rt2x00usb_kick_tx_entry);
        break;
    case QID_RX:
        if (!rt2x00queue_full(queue))
            rt2x00queue_for_each_entry(queue, Q_INDEX, Q_INDEX_DONE,
                           rt2x00usb_kick_rx_entry);
        break;
    default:
        break;
    }
}
EXPORT_SYMBOL_GPL(rt2x00usb_kick_queue);

static bool rt2x00usb_flush_entry(struct queue_entry *entry)
{
    struct rt2x00_dev *rt2x00dev = entry->queue->rt2x00dev;
    struct queue_entry_priv_usb *entry_priv = entry->priv_data;
    struct queue_entry_priv_usb_bcn *bcn_priv = entry->priv_data;

    if (!test_bit(ENTRY_OWNER_DEVICE_DATA, &entry->flags))
        return false;

    usb_kill_urb(entry_priv->urb);

    /*
     * Kill guardian urb (if required by driver).
     */
    if ((entry->queue->qid == QID_BEACON) &&
        (test_bit(REQUIRE_BEACON_GUARD, &rt2x00dev->cap_flags)))
        usb_kill_urb(bcn_priv->guardian_urb);

    return false;
}

void rt2x00usb_flush_queue(struct data_queue *queue, bool drop)
{
    struct work_struct *completion;
    unsigned int i;

    if (drop)
        rt2x00queue_for_each_entry(queue, Q_INDEX_DONE, Q_INDEX,
                       rt2x00usb_flush_entry);

    /*
     * Obtain the queue completion handler
     */
    switch (queue->qid) {
    case QID_AC_VO:
    case QID_AC_VI:
    case QID_AC_BE:
    case QID_AC_BK:
        completion = &queue->rt2x00dev->txdone_work;
        break;
    case QID_RX:
        completion = &queue->rt2x00dev->rxdone_work;
        break;
    default:
        return;
    }

    for (i = 0; i < 10; i++) {
        /*
         * Check if the driver is already done, otherwise we
         * have to sleep a little while to give the driver/hw
         * the oppurtunity to complete interrupt process itself.
         */
        if (rt2x00queue_empty(queue))
            break;

        /*
         * Schedule the completion handler manually, when this
         * worker function runs, it should cleanup the queue.
         */
        queue_work(queue->rt2x00dev->workqueue, completion);

        /*
         * Wait for a little while to give the driver
         * the oppurtunity to recover itself.
         */
        msleep(10);
    }
}
EXPORT_SYMBOL_GPL(rt2x00usb_flush_queue);

static void rt2x00usb_watchdog_tx_dma(struct data_queue *queue)
{
    WARNING(queue->rt2x00dev, "TX queue %d DMA timed out,"
        " invoke forced forced reset\n", queue->qid);

    rt2x00queue_flush_queue(queue, true);
}

static int rt2x00usb_dma_timeout(struct data_queue *queue)
{
    struct queue_entry *entry;

    entry = rt2x00queue_get_entry(queue, Q_INDEX_DMA_DONE);
    return rt2x00queue_dma_timeout(entry);
}

void rt2x00usb_watchdog(struct rt2x00_dev *rt2x00dev)
{
    struct data_queue *queue;

    tx_queue_for_each(rt2x00dev, queue) {
        if (!rt2x00queue_empty(queue)) {
            if (rt2x00usb_dma_timeout(queue))
                rt2x00usb_watchdog_tx_dma(queue);
        }
    }
}
EXPORT_SYMBOL_GPL(rt2x00usb_watchdog);

/*
 * Radio handlers
 */
void rt2x00usb_disable_radio(struct rt2x00_dev *rt2x00dev)
{
    rt2x00usb_vendor_request_sw(rt2x00dev, USB_RX_CONTROL, 0, 0,
                    REGISTER_TIMEOUT);
}
EXPORT_SYMBOL_GPL(rt2x00usb_disable_radio);

/*
 * Device initialization handlers.
 */
void rt2x00usb_clear_entry(struct queue_entry *entry)
{
    entry->flags = 0;

    if (entry->queue->qid == QID_RX)
        rt2x00usb_kick_rx_entry(entry);
}
EXPORT_SYMBOL_GPL(rt2x00usb_clear_entry);

static void rt2x00usb_assign_endpoint(struct data_queue *queue,
                      struct usb_endpoint_descriptor *ep_desc)
{
    struct usb_device *usb_dev = to_usb_device_intf(queue->rt2x00dev->dev);
    int pipe;

    queue->usb_endpoint = usb_endpoint_num(ep_desc);

    if (queue->qid == QID_RX) {
        pipe = usb_rcvbulkpipe(usb_dev, queue->usb_endpoint);
        queue->usb_maxpacket = usb_maxpacket(usb_dev, pipe, 0);
    } else {
        pipe = usb_sndbulkpipe(usb_dev, queue->usb_endpoint);
        queue->usb_maxpacket = usb_maxpacket(usb_dev, pipe, 1);
    }

    if (!queue->usb_maxpacket)
        queue->usb_maxpacket = 1;
}

static int rt2x00usb_find_endpoints(struct rt2x00_dev *rt2x00dev)
{
    struct usb_interface *intf = to_usb_interface(rt2x00dev->dev);
    struct usb_host_interface *intf_desc = intf->cur_altsetting;
    struct usb_endpoint_descriptor *ep_desc;
    struct data_queue *queue = rt2x00dev->tx;
    struct usb_endpoint_descriptor *tx_ep_desc = NULL;
    unsigned int i;

    /*
     * Walk through all available endpoints to search for "bulk in"
     * and "bulk out" endpoints. When we find such endpoints collect
     * the information we need from the descriptor and assign it
     * to the queue.
     */
    for (i = 0; i < intf_desc->desc.bNumEndpoints; i++) {
        ep_desc = &intf_desc->endpoint[i].desc;

        if (usb_endpoint_is_bulk_in(ep_desc)) {
            rt2x00usb_assign_endpoint(rt2x00dev->rx, ep_desc);
        } else if (usb_endpoint_is_bulk_out(ep_desc) &&
               (queue != queue_end(rt2x00dev))) {
            rt2x00usb_assign_endpoint(queue, ep_desc);
            queue = queue_next(queue);

            tx_ep_desc = ep_desc;
        }
    }

    /*
     * At least 1 endpoint for RX and 1 endpoint for TX must be available.
     */
    if (!rt2x00dev->rx->usb_endpoint || !rt2x00dev->tx->usb_endpoint) {
        ERROR(rt2x00dev, "Bulk-in/Bulk-out endpoints not found\n");
        return -EPIPE;
    }

    /*
     * It might be possible not all queues have a dedicated endpoint.
     * Loop through all TX queues and copy the endpoint information
     * which we have gathered from already assigned endpoints.
     */
    txall_queue_for_each(rt2x00dev, queue) {
        if (!queue->usb_endpoint)
            rt2x00usb_assign_endpoint(queue, tx_ep_desc);
    }

    return 0;
}

static int rt2x00usb_alloc_entries(struct data_queue *queue)
{
    struct rt2x00_dev *rt2x00dev = queue->rt2x00dev;
    struct queue_entry_priv_usb *entry_priv;
    struct queue_entry_priv_usb_bcn *bcn_priv;
    unsigned int i;

    for (i = 0; i < queue->limit; i++) {
        entry_priv = queue->entries[i].priv_data;
        entry_priv->urb = usb_alloc_urb(0, GFP_KERNEL);
        if (!entry_priv->urb)
            return -ENOMEM;
    }

    /*
     * If this is not the beacon queue or
     * no guardian byte was required for the beacon,
     * then we are done.
     */
    if (queue->qid != QID_BEACON ||
        !test_bit(REQUIRE_BEACON_GUARD, &rt2x00dev->cap_flags))
        return 0;

    for (i = 0; i < queue->limit; i++) {
        bcn_priv = queue->entries[i].priv_data;
        bcn_priv->guardian_urb = usb_alloc_urb(0, GFP_KERNEL);
        if (!bcn_priv->guardian_urb)
            return -ENOMEM;
    }

    return 0;
}

static void rt2x00usb_free_entries(struct data_queue *queue)
{
    struct rt2x00_dev *rt2x00dev = queue->rt2x00dev;
    struct queue_entry_priv_usb *entry_priv;
    struct queue_entry_priv_usb_bcn *bcn_priv;
    unsigned int i;

    if (!queue->entries)
        return;

    for (i = 0; i < queue->limit; i++) {
        entry_priv = queue->entries[i].priv_data;
        usb_kill_urb(entry_priv->urb);
        usb_free_urb(entry_priv->urb);
    }

    /*
     * If this is not the beacon queue or
     * no guardian byte was required for the beacon,
     * then we are done.
     */
    if (queue->qid != QID_BEACON ||
        !test_bit(REQUIRE_BEACON_GUARD, &rt2x00dev->cap_flags))
        return;

    for (i = 0; i < queue->limit; i++) {
        bcn_priv = queue->entries[i].priv_data;
        usb_kill_urb(bcn_priv->guardian_urb);
        usb_free_urb(bcn_priv->guardian_urb);
    }
}

int rt2x00usb_initialize(struct rt2x00_dev *rt2x00dev)
{
    struct data_queue *queue;
    int status;

    /*
     * Find endpoints for each queue
     */
    status = rt2x00usb_find_endpoints(rt2x00dev);
    if (status)
        goto exit;

    /*
     * Allocate DMA
     */
    queue_for_each(rt2x00dev, queue) {
        status = rt2x00usb_alloc_entries(queue);
        if (status)
            goto exit;
    }

    return 0;

exit:
    rt2x00usb_uninitialize(rt2x00dev);

    return status;
}
EXPORT_SYMBOL_GPL(rt2x00usb_initialize);

void rt2x00usb_uninitialize(struct rt2x00_dev *rt2x00dev)
{
    struct data_queue *queue;

    queue_for_each(rt2x00dev, queue)
        rt2x00usb_free_entries(queue);
}
EXPORT_SYMBOL_GPL(rt2x00usb_uninitialize);

/*
 * USB driver handlers.
 */
static void rt2x00usb_free_reg(struct rt2x00_dev *rt2x00dev)
{
    kfree(rt2x00dev->rf);
    rt2x00dev->rf = NULL;

    kfree(rt2x00dev->eeprom);
    rt2x00dev->eeprom = NULL;

    kfree(rt2x00dev->csr.cache);
    rt2x00dev->csr.cache = NULL;
}

static int rt2x00usb_alloc_reg(struct rt2x00_dev *rt2x00dev)
{
    rt2x00dev->csr.cache = kzalloc(CSR_CACHE_SIZE, GFP_KERNEL);
    if (!rt2x00dev->csr.cache)
        goto exit;

    rt2x00dev->eeprom = kzalloc(rt2x00dev->ops->eeprom_size, GFP_KERNEL);
    if (!rt2x00dev->eeprom)
        goto exit;

    rt2x00dev->rf = kzalloc(rt2x00dev->ops->rf_size, GFP_KERNEL);
    if (!rt2x00dev->rf)
        goto exit;

    return 0;

exit:
    ERROR_PROBE("Failed to allocate registers.\n");

    rt2x00usb_free_reg(rt2x00dev);

    return -ENOMEM;
}

int rt2x00usb_probe(struct usb_interface *usb_intf,
            const struct rt2x00_ops *ops)
{
    struct usb_device *usb_dev = interface_to_usbdev(usb_intf);
    struct ieee80211_hw *hw;
    struct rt2x00_dev *rt2x00dev;
    int retval;

    usb_dev = usb_get_dev(usb_dev);
    usb_reset_device(usb_dev);

    hw = ieee80211_alloc_hw(sizeof(struct rt2x00_dev), ops->hw);
    if (!hw) {
        ERROR_PROBE("Failed to allocate hardware.\n");
        retval = -ENOMEM;
        goto exit_put_device;
    }

    usb_set_intfdata(usb_intf, hw);

    rt2x00dev = hw->priv;
    rt2x00dev->dev = &usb_intf->dev;
    rt2x00dev->ops = ops;
    rt2x00dev->hw = hw;

    rt2x00_set_chip_intf(rt2x00dev, RT2X00_CHIP_INTF_USB);

    INIT_WORK(&rt2x00dev->rxdone_work, rt2x00usb_work_rxdone);
    INIT_WORK(&rt2x00dev->txdone_work, rt2x00usb_work_txdone);
    hrtimer_init(&rt2x00dev->txstatus_timer, CLOCK_MONOTONIC,
             HRTIMER_MODE_REL);

    retval = rt2x00usb_alloc_reg(rt2x00dev);
    if (retval)
        goto exit_free_device;

    retval = rt2x00lib_probe_dev(rt2x00dev);
    if (retval)
        goto exit_free_reg;

    return 0;

exit_free_reg:
    rt2x00usb_free_reg(rt2x00dev);

exit_free_device:
    ieee80211_free_hw(hw);

exit_put_device:
    usb_put_dev(usb_dev);

    usb_set_intfdata(usb_intf, NULL);

    return retval;
}
EXPORT_SYMBOL_GPL(rt2x00usb_probe);

void rt2x00usb_disconnect(struct usb_interface *usb_intf)
{
    struct ieee80211_hw *hw = usb_get_intfdata(usb_intf);
    struct rt2x00_dev *rt2x00dev = hw->priv;

    /*
     * Free all allocated data.
     */
    rt2x00lib_remove_dev(rt2x00dev);
    rt2x00usb_free_reg(rt2x00dev);
    ieee80211_free_hw(hw);

    /*
     * Free the USB device data.
     */
    usb_set_intfdata(usb_intf, NULL);
    usb_put_dev(interface_to_usbdev(usb_intf));
}
EXPORT_SYMBOL_GPL(rt2x00usb_disconnect);

#ifdef CONFIG_PM
int rt2x00usb_suspend(struct usb_interface *usb_intf, pm_message_t state)
{
    struct ieee80211_hw *hw = usb_get_intfdata(usb_intf);
    struct rt2x00_dev *rt2x00dev = hw->priv;

    return rt2x00lib_suspend(rt2x00dev, state);
}
EXPORT_SYMBOL_GPL(rt2x00usb_suspend);

int rt2x00usb_resume(struct usb_interface *usb_intf)
{
    struct ieee80211_hw *hw = usb_get_intfdata(usb_intf);
    struct rt2x00_dev *rt2x00dev = hw->priv;

    return rt2x00lib_resume(rt2x00dev);
}
EXPORT_SYMBOL_GPL(rt2x00usb_resume);
#endif /* CONFIG_PM */

/*
 * rt2x00usb module information.
 */
MODULE_AUTHOR(DRV_PROJECT);
MODULE_VERSION(DRV_VERSION);
MODULE_DESCRIPTION("rt2x00 usb library");
MODULE_LICENSE("GPL");