usb.c

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/*
 * Copyright (c) 2007-2011 Atheros Communications Inc.
 * Copyright (c) 2011-2012 Qualcomm Atheros, 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/usb.h>

#include "debug.h"
#include "core.h"

/* constants */
#define TX_URB_COUNT            32
#define RX_URB_COUNT            32
#define ATH6KL_USB_RX_BUFFER_SIZE  1700

/* tx/rx pipes for usb */
enum ATH6KL_USB_PIPE_ID {
    ATH6KL_USB_PIPE_TX_CTRL = 0,
    ATH6KL_USB_PIPE_TX_DATA_LP,
    ATH6KL_USB_PIPE_TX_DATA_MP,
    ATH6KL_USB_PIPE_TX_DATA_HP,
    ATH6KL_USB_PIPE_RX_CTRL,
    ATH6KL_USB_PIPE_RX_DATA,
    ATH6KL_USB_PIPE_RX_DATA2,
    ATH6KL_USB_PIPE_RX_INT,
    ATH6KL_USB_PIPE_MAX
};

#define ATH6KL_USB_PIPE_INVALID ATH6KL_USB_PIPE_MAX

struct ath6kl_usb_pipe {
    struct list_head urb_list_head;
    struct usb_anchor urb_submitted;
    u32 urb_alloc;
    u32 urb_cnt;
    u32 urb_cnt_thresh;
    unsigned int usb_pipe_handle;
    u32 flags;
    u8 ep_address;
    u8 logical_pipe_num;
    struct ath6kl_usb *ar_usb;
    u16 max_packet_size;
    struct work_struct io_complete_work;
    struct sk_buff_head io_comp_queue;
    struct usb_endpoint_descriptor *ep_desc;
};

#define ATH6KL_USB_PIPE_FLAG_TX    (1 << 0)

/* usb device object */
struct ath6kl_usb {
    /* protects pipe->urb_list_head and  pipe->urb_cnt */
    spinlock_t cs_lock;

    struct usb_device *udev;
    struct usb_interface *interface;
    struct ath6kl_usb_pipe pipes[ATH6KL_USB_PIPE_MAX];
    u8 *diag_cmd_buffer;
    u8 *diag_resp_buffer;
    struct ath6kl *ar;
};

/* usb urb object */
struct ath6kl_urb_context {
    struct list_head link;
    struct ath6kl_usb_pipe *pipe;
    struct sk_buff *skb;
    struct ath6kl *ar;
};

/* USB endpoint definitions */
#define ATH6KL_USB_EP_ADDR_APP_CTRL_IN          0x81
#define ATH6KL_USB_EP_ADDR_APP_DATA_IN          0x82
#define ATH6KL_USB_EP_ADDR_APP_DATA2_IN         0x83
#define ATH6KL_USB_EP_ADDR_APP_INT_IN           0x84

#define ATH6KL_USB_EP_ADDR_APP_CTRL_OUT         0x01
#define ATH6KL_USB_EP_ADDR_APP_DATA_LP_OUT      0x02
#define ATH6KL_USB_EP_ADDR_APP_DATA_MP_OUT      0x03
#define ATH6KL_USB_EP_ADDR_APP_DATA_HP_OUT      0x04

/* diagnostic command defnitions */
#define ATH6KL_USB_CONTROL_REQ_SEND_BMI_CMD        1
#define ATH6KL_USB_CONTROL_REQ_RECV_BMI_RESP       2
#define ATH6KL_USB_CONTROL_REQ_DIAG_CMD            3
#define ATH6KL_USB_CONTROL_REQ_DIAG_RESP           4

#define ATH6KL_USB_CTRL_DIAG_CC_READ               0
#define ATH6KL_USB_CTRL_DIAG_CC_WRITE              1

struct ath6kl_usb_ctrl_diag_cmd_write {
    __le32 cmd;
    __le32 address;
    __le32 value;
    __le32 _pad[1];
} __packed;

struct ath6kl_usb_ctrl_diag_cmd_read {
    __le32 cmd;
    __le32 address;
} __packed;

struct ath6kl_usb_ctrl_diag_resp_read {
    __le32 value;
} __packed;

/* function declarations */
static void ath6kl_usb_recv_complete(struct urb *urb);

#define ATH6KL_USB_IS_BULK_EP(attr) (((attr) & 3) == 0x02)
#define ATH6KL_USB_IS_INT_EP(attr)  (((attr) & 3) == 0x03)
#define ATH6KL_USB_IS_ISOC_EP(attr)  (((attr) & 3) == 0x01)
#define ATH6KL_USB_IS_DIR_IN(addr)  ((addr) & 0x80)

/* pipe/urb operations */
static struct ath6kl_urb_context *
ath6kl_usb_alloc_urb_from_pipe(struct ath6kl_usb_pipe *pipe)
{
    struct ath6kl_urb_context *urb_context = NULL;
    unsigned long flags;

    spin_lock_irqsave(&pipe->ar_usb->cs_lock, flags);
    if (!list_empty(&pipe->urb_list_head)) {
        urb_context =
            list_first_entry(&pipe->urb_list_head,
                     struct ath6kl_urb_context, link);
        list_del(&urb_context->link);
        pipe->urb_cnt--;
    }
    spin_unlock_irqrestore(&pipe->ar_usb->cs_lock, flags);

    return urb_context;
}

static void ath6kl_usb_free_urb_to_pipe(struct ath6kl_usb_pipe *pipe,
                    struct ath6kl_urb_context *urb_context)
{
    unsigned long flags;

    spin_lock_irqsave(&pipe->ar_usb->cs_lock, flags);
    pipe->urb_cnt++;

    list_add(&urb_context->link, &pipe->urb_list_head);
    spin_unlock_irqrestore(&pipe->ar_usb->cs_lock, flags);
}

static void ath6kl_usb_cleanup_recv_urb(struct ath6kl_urb_context *urb_context)
{
    if (urb_context->skb != NULL) {
        dev_kfree_skb(urb_context->skb);
        urb_context->skb = NULL;
    }

    ath6kl_usb_free_urb_to_pipe(urb_context->pipe, urb_context);
}

static inline struct ath6kl_usb *ath6kl_usb_priv(struct ath6kl *ar)
{
    return ar->hif_priv;
}

/* pipe resource allocation/cleanup */
static int ath6kl_usb_alloc_pipe_resources(struct ath6kl_usb_pipe *pipe,
                       int urb_cnt)
{
    struct ath6kl_urb_context *urb_context;
    int status = 0, i;

    INIT_LIST_HEAD(&pipe->urb_list_head);
    init_usb_anchor(&pipe->urb_submitted);

    for (i = 0; i < urb_cnt; i++) {
        urb_context = kzalloc(sizeof(struct ath6kl_urb_context),
                      GFP_KERNEL);
        if (urb_context == NULL)
            /* FIXME: set status to -ENOMEM */
            break;

        urb_context->pipe = pipe;

        /*
         * we are only allocate the urb contexts here, the actual URB
         * is allocated from the kernel as needed to do a transaction
         */
        pipe->urb_alloc++;
        ath6kl_usb_free_urb_to_pipe(pipe, urb_context);
    }

    ath6kl_dbg(ATH6KL_DBG_USB,
           "ath6kl usb: alloc resources lpipe:%d hpipe:0x%X urbs:%d\n",
           pipe->logical_pipe_num, pipe->usb_pipe_handle,
           pipe->urb_alloc);

    return status;
}

static void ath6kl_usb_free_pipe_resources(struct ath6kl_usb_pipe *pipe)
{
    struct ath6kl_urb_context *urb_context;

    if (pipe->ar_usb == NULL) {
        /* nothing allocated for this pipe */
        return;
    }

    ath6kl_dbg(ATH6KL_DBG_USB,
           "ath6kl usb: free resources lpipe:%d"
           "hpipe:0x%X urbs:%d avail:%d\n",
           pipe->logical_pipe_num, pipe->usb_pipe_handle,
           pipe->urb_alloc, pipe->urb_cnt);

    if (pipe->urb_alloc != pipe->urb_cnt) {
        ath6kl_dbg(ATH6KL_DBG_USB,
               "ath6kl usb: urb leak! lpipe:%d"
               "hpipe:0x%X urbs:%d avail:%d\n",
               pipe->logical_pipe_num, pipe->usb_pipe_handle,
               pipe->urb_alloc, pipe->urb_cnt);
    }

    while (true) {
        urb_context = ath6kl_usb_alloc_urb_from_pipe(pipe);
        if (urb_context == NULL)
            break;
        kfree(urb_context);
    }

}

static void ath6kl_usb_cleanup_pipe_resources(struct ath6kl_usb *ar_usb)
{
    int i;

    for (i = 0; i < ATH6KL_USB_PIPE_MAX; i++)
        ath6kl_usb_free_pipe_resources(&ar_usb->pipes[i]);

}

static u8 ath6kl_usb_get_logical_pipe_num(struct ath6kl_usb *ar_usb,
                      u8 ep_address, int *urb_count)
{
    u8 pipe_num = ATH6KL_USB_PIPE_INVALID;

    switch (ep_address) {
    case ATH6KL_USB_EP_ADDR_APP_CTRL_IN:
        pipe_num = ATH6KL_USB_PIPE_RX_CTRL;
        *urb_count = RX_URB_COUNT;
        break;
    case ATH6KL_USB_EP_ADDR_APP_DATA_IN:
        pipe_num = ATH6KL_USB_PIPE_RX_DATA;
        *urb_count = RX_URB_COUNT;
        break;
    case ATH6KL_USB_EP_ADDR_APP_INT_IN:
        pipe_num = ATH6KL_USB_PIPE_RX_INT;
        *urb_count = RX_URB_COUNT;
        break;
    case ATH6KL_USB_EP_ADDR_APP_DATA2_IN:
        pipe_num = ATH6KL_USB_PIPE_RX_DATA2;
        *urb_count = RX_URB_COUNT;
        break;
    case ATH6KL_USB_EP_ADDR_APP_CTRL_OUT:
        pipe_num = ATH6KL_USB_PIPE_TX_CTRL;
        *urb_count = TX_URB_COUNT;
        break;
    case ATH6KL_USB_EP_ADDR_APP_DATA_LP_OUT:
        pipe_num = ATH6KL_USB_PIPE_TX_DATA_LP;
        *urb_count = TX_URB_COUNT;
        break;
    case ATH6KL_USB_EP_ADDR_APP_DATA_MP_OUT:
        pipe_num = ATH6KL_USB_PIPE_TX_DATA_MP;
        *urb_count = TX_URB_COUNT;
        break;
    case ATH6KL_USB_EP_ADDR_APP_DATA_HP_OUT:
        pipe_num = ATH6KL_USB_PIPE_TX_DATA_HP;
        *urb_count = TX_URB_COUNT;
        break;
    default:
        /* note: there may be endpoints not currently used */
        break;
    }

    return pipe_num;
}

static int ath6kl_usb_setup_pipe_resources(struct ath6kl_usb *ar_usb)
{
    struct usb_interface *interface = ar_usb->interface;
    struct usb_host_interface *iface_desc = interface->cur_altsetting;
    struct usb_endpoint_descriptor *endpoint;
    struct ath6kl_usb_pipe *pipe;
    int i, urbcount, status = 0;
    u8 pipe_num;

    ath6kl_dbg(ATH6KL_DBG_USB, "setting up USB Pipes using interface\n");

    /* walk decriptors and setup pipes */
    for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) {
        endpoint = &iface_desc->endpoint[i].desc;

        if (ATH6KL_USB_IS_BULK_EP(endpoint->bmAttributes)) {
            ath6kl_dbg(ATH6KL_DBG_USB,
                   "%s Bulk Ep:0x%2.2X maxpktsz:%d\n",
                   ATH6KL_USB_IS_DIR_IN
                   (endpoint->bEndpointAddress) ?
                   "RX" : "TX", endpoint->bEndpointAddress,
                   le16_to_cpu(endpoint->wMaxPacketSize));
        } else if (ATH6KL_USB_IS_INT_EP(endpoint->bmAttributes)) {
            ath6kl_dbg(ATH6KL_DBG_USB,
                   "%s Int Ep:0x%2.2X maxpktsz:%d interval:%d\n",
                   ATH6KL_USB_IS_DIR_IN
                   (endpoint->bEndpointAddress) ?
                   "RX" : "TX", endpoint->bEndpointAddress,
                   le16_to_cpu(endpoint->wMaxPacketSize),
                   endpoint->bInterval);
        } else if (ATH6KL_USB_IS_ISOC_EP(endpoint->bmAttributes)) {
            /* TODO for ISO */
            ath6kl_dbg(ATH6KL_DBG_USB,
                   "%s ISOC Ep:0x%2.2X maxpktsz:%d interval:%d\n",
                   ATH6KL_USB_IS_DIR_IN
                   (endpoint->bEndpointAddress) ?
                   "RX" : "TX", endpoint->bEndpointAddress,
                   le16_to_cpu(endpoint->wMaxPacketSize),
                   endpoint->bInterval);
        }
        urbcount = 0;

        pipe_num =
            ath6kl_usb_get_logical_pipe_num(ar_usb,
                            endpoint->bEndpointAddress,
                            &urbcount);
        if (pipe_num == ATH6KL_USB_PIPE_INVALID)
            continue;

        pipe = &ar_usb->pipes[pipe_num];
        if (pipe->ar_usb != NULL) {
            /* hmmm..pipe was already setup */
            continue;
        }

        pipe->ar_usb = ar_usb;
        pipe->logical_pipe_num = pipe_num;
        pipe->ep_address = endpoint->bEndpointAddress;
        pipe->max_packet_size = le16_to_cpu(endpoint->wMaxPacketSize);

        if (ATH6KL_USB_IS_BULK_EP(endpoint->bmAttributes)) {
            if (ATH6KL_USB_IS_DIR_IN(pipe->ep_address)) {
                pipe->usb_pipe_handle =
                    usb_rcvbulkpipe(ar_usb->udev,
                            pipe->ep_address);
            } else {
                pipe->usb_pipe_handle =
                    usb_sndbulkpipe(ar_usb->udev,
                            pipe->ep_address);
            }
        } else if (ATH6KL_USB_IS_INT_EP(endpoint->bmAttributes)) {
            if (ATH6KL_USB_IS_DIR_IN(pipe->ep_address)) {
                pipe->usb_pipe_handle =
                    usb_rcvintpipe(ar_usb->udev,
                           pipe->ep_address);
            } else {
                pipe->usb_pipe_handle =
                    usb_sndintpipe(ar_usb->udev,
                           pipe->ep_address);
            }
        } else if (ATH6KL_USB_IS_ISOC_EP(endpoint->bmAttributes)) {
            /* TODO for ISO */
            if (ATH6KL_USB_IS_DIR_IN(pipe->ep_address)) {
                pipe->usb_pipe_handle =
                    usb_rcvisocpipe(ar_usb->udev,
                            pipe->ep_address);
            } else {
                pipe->usb_pipe_handle =
                    usb_sndisocpipe(ar_usb->udev,
                            pipe->ep_address);
            }
        }

        pipe->ep_desc = endpoint;

        if (!ATH6KL_USB_IS_DIR_IN(pipe->ep_address))
            pipe->flags |= ATH6KL_USB_PIPE_FLAG_TX;

        status = ath6kl_usb_alloc_pipe_resources(pipe, urbcount);
        if (status != 0)
            break;
    }

    return status;
}

/* pipe operations */
static void ath6kl_usb_post_recv_transfers(struct ath6kl_usb_pipe *recv_pipe,
                       int buffer_length)
{
    struct ath6kl_urb_context *urb_context;
    struct urb *urb;
    int usb_status;

    while (true) {
        urb_context = ath6kl_usb_alloc_urb_from_pipe(recv_pipe);
        if (urb_context == NULL)
            break;

        urb_context->skb = dev_alloc_skb(buffer_length);
        if (urb_context->skb == NULL)
            goto err_cleanup_urb;

        urb = usb_alloc_urb(0, GFP_ATOMIC);
        if (urb == NULL)
            goto err_cleanup_urb;

        usb_fill_bulk_urb(urb,
                  recv_pipe->ar_usb->udev,
                  recv_pipe->usb_pipe_handle,
                  urb_context->skb->data,
                  buffer_length,
                  ath6kl_usb_recv_complete, urb_context);

        ath6kl_dbg(ATH6KL_DBG_USB_BULK,
               "ath6kl usb: bulk recv submit:%d, 0x%X (ep:0x%2.2X), %d bytes buf:0x%p\n",
               recv_pipe->logical_pipe_num,
               recv_pipe->usb_pipe_handle, recv_pipe->ep_address,
               buffer_length, urb_context->skb);

        usb_anchor_urb(urb, &recv_pipe->urb_submitted);
        usb_status = usb_submit_urb(urb, GFP_ATOMIC);

        if (usb_status) {
            ath6kl_dbg(ATH6KL_DBG_USB_BULK,
                   "ath6kl usb : usb bulk recv failed %d\n",
                   usb_status);
            usb_unanchor_urb(urb);
            usb_free_urb(urb);
            goto err_cleanup_urb;
        }
        usb_free_urb(urb);
    }
    return;

err_cleanup_urb:
    ath6kl_usb_cleanup_recv_urb(urb_context);
    return;
}

static void ath6kl_usb_flush_all(struct ath6kl_usb *ar_usb)
{
    int i;

    for (i = 0; i < ATH6KL_USB_PIPE_MAX; i++) {
        if (ar_usb->pipes[i].ar_usb != NULL)
            usb_kill_anchored_urbs(&ar_usb->pipes[i].urb_submitted);
    }

    /*
     * Flushing any pending I/O may schedule work this call will block
     * until all scheduled work runs to completion.
     */
    flush_scheduled_work();
}

static void ath6kl_usb_start_recv_pipes(struct ath6kl_usb *ar_usb)
{
    /*
     * note: control pipe is no longer used
     * ar_usb->pipes[ATH6KL_USB_PIPE_RX_CTRL].urb_cnt_thresh =
     *      ar_usb->pipes[ATH6KL_USB_PIPE_RX_CTRL].urb_alloc/2;
     * ath6kl_usb_post_recv_transfers(&ar_usb->
     *      pipes[ATH6KL_USB_PIPE_RX_CTRL],
     *      ATH6KL_USB_RX_BUFFER_SIZE);
     */

    ar_usb->pipes[ATH6KL_USB_PIPE_RX_DATA].urb_cnt_thresh =
        ar_usb->pipes[ATH6KL_USB_PIPE_RX_DATA].urb_alloc / 2;
    ath6kl_usb_post_recv_transfers(&ar_usb->pipes[ATH6KL_USB_PIPE_RX_DATA],
                       ATH6KL_USB_RX_BUFFER_SIZE);
}

/* hif usb rx/tx completion functions */
static void ath6kl_usb_recv_complete(struct urb *urb)
{
    struct ath6kl_urb_context *urb_context = urb->context;
    struct ath6kl_usb_pipe *pipe = urb_context->pipe;
    struct sk_buff *skb = NULL;
    int status = 0;

    ath6kl_dbg(ATH6KL_DBG_USB_BULK,
           "%s: recv pipe: %d, stat:%d, len:%d urb:0x%p\n", __func__,
           pipe->logical_pipe_num, urb->status, urb->actual_length,
           urb);

    if (urb->status != 0) {
        status = -EIO;
        switch (urb->status) {
        case -ECONNRESET:
        case -ENOENT:
        case -ESHUTDOWN:
            /*
             * no need to spew these errors when device
             * removed or urb killed due to driver shutdown
             */
            status = -ECANCELED;
            break;
        default:
            ath6kl_dbg(ATH6KL_DBG_USB_BULK,
                   "%s recv pipe: %d (ep:0x%2.2X), failed:%d\n",
                   __func__, pipe->logical_pipe_num,
                   pipe->ep_address, urb->status);
            break;
        }
        goto cleanup_recv_urb;
    }

    if (urb->actual_length == 0)
        goto cleanup_recv_urb;

    skb = urb_context->skb;

    /* we are going to pass it up */
    urb_context->skb = NULL;
    skb_put(skb, urb->actual_length);

    /* note: queue implements a lock */
    skb_queue_tail(&pipe->io_comp_queue, skb);
    schedule_work(&pipe->io_complete_work);

cleanup_recv_urb:
    ath6kl_usb_cleanup_recv_urb(urb_context);

    if (status == 0 &&
        pipe->urb_cnt >= pipe->urb_cnt_thresh) {
        /* our free urbs are piling up, post more transfers */
        ath6kl_usb_post_recv_transfers(pipe, ATH6KL_USB_RX_BUFFER_SIZE);
    }
}

static void ath6kl_usb_usb_transmit_complete(struct urb *urb)
{
    struct ath6kl_urb_context *urb_context = urb->context;
    struct ath6kl_usb_pipe *pipe = urb_context->pipe;
    struct sk_buff *skb;

    ath6kl_dbg(ATH6KL_DBG_USB_BULK,
           "%s: pipe: %d, stat:%d, len:%d\n",
           __func__, pipe->logical_pipe_num, urb->status,
           urb->actual_length);

    if (urb->status != 0) {
        ath6kl_dbg(ATH6KL_DBG_USB_BULK,
               "%s:  pipe: %d, failed:%d\n",
               __func__, pipe->logical_pipe_num, urb->status);
    }

    skb = urb_context->skb;
    urb_context->skb = NULL;
    ath6kl_usb_free_urb_to_pipe(urb_context->pipe, urb_context);

    /* note: queue implements a lock */
    skb_queue_tail(&pipe->io_comp_queue, skb);
    schedule_work(&pipe->io_complete_work);
}

static void ath6kl_usb_io_comp_work(struct work_struct *work)
{
    struct ath6kl_usb_pipe *pipe = container_of(work,
                            struct ath6kl_usb_pipe,
                            io_complete_work);
    struct ath6kl_usb *ar_usb;
    struct sk_buff *skb;

    ar_usb = pipe->ar_usb;

    while ((skb = skb_dequeue(&pipe->io_comp_queue))) {
        if (pipe->flags & ATH6KL_USB_PIPE_FLAG_TX) {
            ath6kl_dbg(ATH6KL_DBG_USB_BULK,
                   "ath6kl usb xmit callback buf:0x%p\n", skb);
            ath6kl_core_tx_complete(ar_usb->ar, skb);
        } else {
            ath6kl_dbg(ATH6KL_DBG_USB_BULK,
                   "ath6kl usb recv callback buf:0x%p\n", skb);
            ath6kl_core_rx_complete(ar_usb->ar, skb,
                        pipe->logical_pipe_num);
        }
    }
}

#define ATH6KL_USB_MAX_DIAG_CMD (sizeof(struct ath6kl_usb_ctrl_diag_cmd_write))
#define ATH6KL_USB_MAX_DIAG_RESP (sizeof(struct ath6kl_usb_ctrl_diag_resp_read))

static void ath6kl_usb_destroy(struct ath6kl_usb *ar_usb)
{
    ath6kl_usb_flush_all(ar_usb);

    ath6kl_usb_cleanup_pipe_resources(ar_usb);

    usb_set_intfdata(ar_usb->interface, NULL);

    kfree(ar_usb->diag_cmd_buffer);
    kfree(ar_usb->diag_resp_buffer);

    kfree(ar_usb);
}

static struct ath6kl_usb *ath6kl_usb_create(struct usb_interface *interface)
{
    struct usb_device *dev = interface_to_usbdev(interface);
    struct ath6kl_usb *ar_usb;
    struct ath6kl_usb_pipe *pipe;
    int status = 0;
    int i;

    ar_usb = kzalloc(sizeof(struct ath6kl_usb), GFP_KERNEL);
    if (ar_usb == NULL)
        goto fail_ath6kl_usb_create;

    usb_set_intfdata(interface, ar_usb);
    spin_lock_init(&(ar_usb->cs_lock));
    ar_usb->udev = dev;
    ar_usb->interface = interface;

    for (i = 0; i < ATH6KL_USB_PIPE_MAX; i++) {
        pipe = &ar_usb->pipes[i];
        INIT_WORK(&pipe->io_complete_work,
              ath6kl_usb_io_comp_work);
        skb_queue_head_init(&pipe->io_comp_queue);
    }

    ar_usb->diag_cmd_buffer = kzalloc(ATH6KL_USB_MAX_DIAG_CMD, GFP_KERNEL);
    if (ar_usb->diag_cmd_buffer == NULL) {
        status = -ENOMEM;
        goto fail_ath6kl_usb_create;
    }

    ar_usb->diag_resp_buffer = kzalloc(ATH6KL_USB_MAX_DIAG_RESP,
                       GFP_KERNEL);
    if (ar_usb->diag_resp_buffer == NULL) {
        status = -ENOMEM;
        goto fail_ath6kl_usb_create;
    }

    status = ath6kl_usb_setup_pipe_resources(ar_usb);

fail_ath6kl_usb_create:
    if (status != 0) {
        ath6kl_usb_destroy(ar_usb);
        ar_usb = NULL;
    }
    return ar_usb;
}

static void ath6kl_usb_device_detached(struct usb_interface *interface)
{
    struct ath6kl_usb *ar_usb;

    ar_usb = usb_get_intfdata(interface);
    if (ar_usb == NULL)
        return;

    ath6kl_stop_txrx(ar_usb->ar);

    /* Delay to wait for the target to reboot */
    mdelay(20);
    ath6kl_core_cleanup(ar_usb->ar);
    ath6kl_usb_destroy(ar_usb);
}

/* exported hif usb APIs for htc pipe */
static void hif_start(struct ath6kl *ar)
{
    struct ath6kl_usb *device = ath6kl_usb_priv(ar);
    int i;

    ath6kl_usb_start_recv_pipes(device);

    /* set the TX resource avail threshold for each TX pipe */
    for (i = ATH6KL_USB_PIPE_TX_CTRL;
         i <= ATH6KL_USB_PIPE_TX_DATA_HP; i++) {
        device->pipes[i].urb_cnt_thresh =
            device->pipes[i].urb_alloc / 2;
    }
}

static int ath6kl_usb_send(struct ath6kl *ar, u8 PipeID,
               struct sk_buff *hdr_skb, struct sk_buff *skb)
{
    struct ath6kl_usb *device = ath6kl_usb_priv(ar);
    struct ath6kl_usb_pipe *pipe = &device->pipes[PipeID];
    struct ath6kl_urb_context *urb_context;
    int usb_status, status = 0;
    struct urb *urb;
    u8 *data;
    u32 len;

    ath6kl_dbg(ATH6KL_DBG_USB_BULK, "+%s pipe : %d, buf:0x%p\n",
           __func__, PipeID, skb);

    urb_context = ath6kl_usb_alloc_urb_from_pipe(pipe);

    if (urb_context == NULL) {
        /*
         * TODO: it is possible to run out of urbs if
         * 2 endpoints map to the same pipe ID
         */
        ath6kl_dbg(ATH6KL_DBG_USB_BULK,
               "%s pipe:%d no urbs left. URB Cnt : %d\n",
               __func__, PipeID, pipe->urb_cnt);
        status = -ENOMEM;
        goto fail_hif_send;
    }

    urb_context->skb = skb;

    data = skb->data;
    len = skb->len;

    urb = usb_alloc_urb(0, GFP_ATOMIC);
    if (urb == NULL) {
        status = -ENOMEM;
        ath6kl_usb_free_urb_to_pipe(urb_context->pipe,
                        urb_context);
        goto fail_hif_send;
    }

    usb_fill_bulk_urb(urb,
              device->udev,
              pipe->usb_pipe_handle,
              data,
              len,
              ath6kl_usb_usb_transmit_complete, urb_context);

    if ((len % pipe->max_packet_size) == 0) {
        /* hit a max packet boundary on this pipe */
        urb->transfer_flags |= URB_ZERO_PACKET;
    }

    ath6kl_dbg(ATH6KL_DBG_USB_BULK,
           "athusb bulk send submit:%d, 0x%X (ep:0x%2.2X), %d bytes\n",
           pipe->logical_pipe_num, pipe->usb_pipe_handle,
           pipe->ep_address, len);

    usb_anchor_urb(urb, &pipe->urb_submitted);
    usb_status = usb_submit_urb(urb, GFP_ATOMIC);

    if (usb_status) {
        ath6kl_dbg(ATH6KL_DBG_USB_BULK,
               "ath6kl usb : usb bulk transmit failed %d\n",
               usb_status);
        usb_unanchor_urb(urb);
        ath6kl_usb_free_urb_to_pipe(urb_context->pipe,
                        urb_context);
        status = -EINVAL;
    }
    usb_free_urb(urb);

fail_hif_send:
    return status;
}

static void hif_stop(struct ath6kl *ar)
{
    struct ath6kl_usb *device = ath6kl_usb_priv(ar);

    ath6kl_usb_flush_all(device);
}

static void ath6kl_usb_get_default_pipe(struct ath6kl *ar,
                    u8 *ul_pipe, u8 *dl_pipe)
{
    *ul_pipe = ATH6KL_USB_PIPE_TX_CTRL;
    *dl_pipe = ATH6KL_USB_PIPE_RX_CTRL;
}

static int ath6kl_usb_map_service_pipe(struct ath6kl *ar, u16 svc_id,
                       u8 *ul_pipe, u8 *dl_pipe)
{
    int status = 0;

    switch (svc_id) {
    case HTC_CTRL_RSVD_SVC:
    case WMI_CONTROL_SVC:
        *ul_pipe = ATH6KL_USB_PIPE_TX_CTRL;
        /* due to large control packets, shift to data pipe */
        *dl_pipe = ATH6KL_USB_PIPE_RX_DATA;
        break;
    case WMI_DATA_BE_SVC:
    case WMI_DATA_BK_SVC:
        *ul_pipe = ATH6KL_USB_PIPE_TX_DATA_LP;
        /*
        * Disable rxdata2 directly, it will be enabled
        * if FW enable rxdata2
        */
        *dl_pipe = ATH6KL_USB_PIPE_RX_DATA;
        break;
    case WMI_DATA_VI_SVC:
        *ul_pipe = ATH6KL_USB_PIPE_TX_DATA_MP;
        /*
        * Disable rxdata2 directly, it will be enabled
        * if FW enable rxdata2
        */
        *dl_pipe = ATH6KL_USB_PIPE_RX_DATA;
        break;
    case WMI_DATA_VO_SVC:
        *ul_pipe = ATH6KL_USB_PIPE_TX_DATA_HP;
        /*
        * Disable rxdata2 directly, it will be enabled
        * if FW enable rxdata2
        */
        *dl_pipe = ATH6KL_USB_PIPE_RX_DATA;
        break;
    default:
        status = -EPERM;
        break;
    }

    return status;
}

static u16 ath6kl_usb_get_free_queue_number(struct ath6kl *ar, u8 pipe_id)
{
    struct ath6kl_usb *device = ath6kl_usb_priv(ar);

    return device->pipes[pipe_id].urb_cnt;
}

static void hif_detach_htc(struct ath6kl *ar)
{
    struct ath6kl_usb *device = ath6kl_usb_priv(ar);

    ath6kl_usb_flush_all(device);
}

static int ath6kl_usb_submit_ctrl_out(struct ath6kl_usb *ar_usb,
                   u8 req, u16 value, u16 index, void *data,
                   u32 size)
{
    u8 *buf = NULL;
    int ret;

    if (size > 0) {
        buf = kmalloc(size, GFP_KERNEL);
        if (buf == NULL)
            return -ENOMEM;

        memcpy(buf, data, size);
    }

    /* note: if successful returns number of bytes transfered */
    ret = usb_control_msg(ar_usb->udev,
                  usb_sndctrlpipe(ar_usb->udev, 0),
                  req,
                  USB_DIR_OUT | USB_TYPE_VENDOR |
                  USB_RECIP_DEVICE, value, index, buf,
                  size, 1000);

    if (ret < 0) {
        ath6kl_dbg(ATH6KL_DBG_USB, "%s failed,result = %d\n",
               __func__, ret);
    }

    kfree(buf);

    return 0;
}

static int ath6kl_usb_submit_ctrl_in(struct ath6kl_usb *ar_usb,
                  u8 req, u16 value, u16 index, void *data,
                  u32 size)
{
    u8 *buf = NULL;
    int ret;

    if (size > 0) {
        buf = kmalloc(size, GFP_KERNEL);
        if (buf == NULL)
            return -ENOMEM;
    }

    /* note: if successful returns number of bytes transfered */
    ret = usb_control_msg(ar_usb->udev,
                 usb_rcvctrlpipe(ar_usb->udev, 0),
                 req,
                 USB_DIR_IN | USB_TYPE_VENDOR |
                 USB_RECIP_DEVICE, value, index, buf,
                 size, 2 * HZ);

    if (ret < 0) {
        ath6kl_dbg(ATH6KL_DBG_USB, "%s failed,result = %d\n",
               __func__, ret);
    }

    memcpy((u8 *) data, buf, size);

    kfree(buf);

    return 0;
}

static int ath6kl_usb_ctrl_msg_exchange(struct ath6kl_usb *ar_usb,
                     u8 req_val, u8 *req_buf, u32 req_len,
                     u8 resp_val, u8 *resp_buf, u32 *resp_len)
{
    int ret;

    /* send command */
    ret = ath6kl_usb_submit_ctrl_out(ar_usb, req_val, 0, 0,
                     req_buf, req_len);

    if (ret != 0)
        return ret;

    if (resp_buf == NULL) {
        /* no expected response */
        return ret;
    }

    /* get response */
    ret = ath6kl_usb_submit_ctrl_in(ar_usb, resp_val, 0, 0,
                    resp_buf, *resp_len);

    return ret;
}

static int ath6kl_usb_diag_read32(struct ath6kl *ar, u32 address, u32 *data)
{
    struct ath6kl_usb *ar_usb = ar->hif_priv;
    struct ath6kl_usb_ctrl_diag_resp_read *resp;
    struct ath6kl_usb_ctrl_diag_cmd_read *cmd;
    u32 resp_len;
    int ret;

    cmd = (struct ath6kl_usb_ctrl_diag_cmd_read *) ar_usb->diag_cmd_buffer;

    memset(cmd, 0, sizeof(*cmd));
    cmd->cmd = ATH6KL_USB_CTRL_DIAG_CC_READ;
    cmd->address = cpu_to_le32(address);
    resp_len = sizeof(*resp);

    ret = ath6kl_usb_ctrl_msg_exchange(ar_usb,
                ATH6KL_USB_CONTROL_REQ_DIAG_CMD,
                (u8 *) cmd,
                sizeof(struct ath6kl_usb_ctrl_diag_cmd_write),
                ATH6KL_USB_CONTROL_REQ_DIAG_RESP,
                ar_usb->diag_resp_buffer, &resp_len);

    if (ret)
        return ret;

    resp = (struct ath6kl_usb_ctrl_diag_resp_read *)
        ar_usb->diag_resp_buffer;

    *data = le32_to_cpu(resp->value);

    return ret;
}

static int ath6kl_usb_diag_write32(struct ath6kl *ar, u32 address, __le32 data)
{
    struct ath6kl_usb *ar_usb = ar->hif_priv;
    struct ath6kl_usb_ctrl_diag_cmd_write *cmd;

    cmd = (struct ath6kl_usb_ctrl_diag_cmd_write *) ar_usb->diag_cmd_buffer;

    memset(cmd, 0, sizeof(struct ath6kl_usb_ctrl_diag_cmd_write));
    cmd->cmd = cpu_to_le32(ATH6KL_USB_CTRL_DIAG_CC_WRITE);
    cmd->address = cpu_to_le32(address);
    cmd->value = data;

    return ath6kl_usb_ctrl_msg_exchange(ar_usb,
                        ATH6KL_USB_CONTROL_REQ_DIAG_CMD,
                        (u8 *) cmd,
                        sizeof(*cmd),
                        0, NULL, NULL);

}

static int ath6kl_usb_bmi_read(struct ath6kl *ar, u8 *buf, u32 len)
{
    struct ath6kl_usb *ar_usb = ar->hif_priv;
    int ret;

    /* get response */
    ret = ath6kl_usb_submit_ctrl_in(ar_usb,
                    ATH6KL_USB_CONTROL_REQ_RECV_BMI_RESP,
                    0, 0, buf, len);
    if (ret != 0) {
        ath6kl_err("Unable to read the bmi data from the device: %d\n",
               ret);
        return ret;
    }

    return 0;
}

static int ath6kl_usb_bmi_write(struct ath6kl *ar, u8 *buf, u32 len)
{
    struct ath6kl_usb *ar_usb = ar->hif_priv;
    int ret;

    /* send command */
    ret = ath6kl_usb_submit_ctrl_out(ar_usb,
                     ATH6KL_USB_CONTROL_REQ_SEND_BMI_CMD,
                     0, 0, buf, len);
    if (ret != 0) {
        ath6kl_err("unable to send the bmi data to the device: %d\n",
               ret);
        return ret;
    }

    return 0;
}

static int ath6kl_usb_power_on(struct ath6kl *ar)
{
    hif_start(ar);
    return 0;
}

static int ath6kl_usb_power_off(struct ath6kl *ar)
{
    hif_detach_htc(ar);
    return 0;
}

static void ath6kl_usb_stop(struct ath6kl *ar)
{
    hif_stop(ar);
}

static void ath6kl_usb_cleanup_scatter(struct ath6kl *ar)
{
    /*
     * USB doesn't support it. Just return.
     */
    return;
}

static const struct ath6kl_hif_ops ath6kl_usb_ops = {
    .diag_read32 = ath6kl_usb_diag_read32,
    .diag_write32 = ath6kl_usb_diag_write32,
    .bmi_read = ath6kl_usb_bmi_read,
    .bmi_write = ath6kl_usb_bmi_write,
    .power_on = ath6kl_usb_power_on,
    .power_off = ath6kl_usb_power_off,
    .stop = ath6kl_usb_stop,
    .pipe_send = ath6kl_usb_send,
    .pipe_get_default = ath6kl_usb_get_default_pipe,
    .pipe_map_service = ath6kl_usb_map_service_pipe,
    .pipe_get_free_queue_number = ath6kl_usb_get_free_queue_number,
    .cleanup_scatter = ath6kl_usb_cleanup_scatter,
};

/* ath6kl usb driver registered functions */
static int ath6kl_usb_probe(struct usb_interface *interface,
                const struct usb_device_id *id)
{
    struct usb_device *dev = interface_to_usbdev(interface);
    struct ath6kl *ar;
    struct ath6kl_usb *ar_usb = NULL;
    int vendor_id, product_id;
    int ret = 0;

    usb_get_dev(dev);

    vendor_id = le16_to_cpu(dev->descriptor.idVendor);
    product_id = le16_to_cpu(dev->descriptor.idProduct);

    ath6kl_dbg(ATH6KL_DBG_USB, "vendor_id = %04x\n", vendor_id);
    ath6kl_dbg(ATH6KL_DBG_USB, "product_id = %04x\n", product_id);

    if (interface->cur_altsetting)
        ath6kl_dbg(ATH6KL_DBG_USB, "USB Interface %d\n",
               interface->cur_altsetting->desc.bInterfaceNumber);


    if (dev->speed == USB_SPEED_HIGH)
        ath6kl_dbg(ATH6KL_DBG_USB, "USB 2.0 Host\n");
    else
        ath6kl_dbg(ATH6KL_DBG_USB, "USB 1.1 Host\n");

    ar_usb = ath6kl_usb_create(interface);

    if (ar_usb == NULL) {
        ret = -ENOMEM;
        goto err_usb_put;
    }

    ar = ath6kl_core_create(&ar_usb->udev->dev);
    if (ar == NULL) {
        ath6kl_err("Failed to alloc ath6kl core\n");
        ret = -ENOMEM;
        goto err_usb_destroy;
    }

    ar->hif_priv = ar_usb;
    ar->hif_type = ATH6KL_HIF_TYPE_USB;
    ar->hif_ops = &ath6kl_usb_ops;
    ar->mbox_info.block_size = 16;
    ar->bmi.max_data_size = 252;

    ar_usb->ar = ar;

    ret = ath6kl_core_init(ar, ATH6KL_HTC_TYPE_PIPE);
    if (ret) {
        ath6kl_err("Failed to init ath6kl core: %d\n", ret);
        goto err_core_free;
    }

    return ret;

err_core_free:
    ath6kl_core_destroy(ar);
err_usb_destroy:
    ath6kl_usb_destroy(ar_usb);
err_usb_put:
    usb_put_dev(dev);

    return ret;
}

static void ath6kl_usb_remove(struct usb_interface *interface)
{
    usb_put_dev(interface_to_usbdev(interface));
    ath6kl_usb_device_detached(interface);
}

#ifdef CONFIG_PM

static int ath6kl_usb_suspend(struct usb_interface *interface,
                  pm_message_t message)
{
    struct ath6kl_usb *device;
    device = usb_get_intfdata(interface);

    ath6kl_usb_flush_all(device);
    return 0;
}

static int ath6kl_usb_resume(struct usb_interface *interface)
{
    struct ath6kl_usb *device;
    device = usb_get_intfdata(interface);

    ath6kl_usb_post_recv_transfers(&device->pipes[ATH6KL_USB_PIPE_RX_DATA],
                       ATH6KL_USB_RX_BUFFER_SIZE);
    ath6kl_usb_post_recv_transfers(&device->pipes[ATH6KL_USB_PIPE_RX_DATA2],
                       ATH6KL_USB_RX_BUFFER_SIZE);

    return 0;
}

static int ath6kl_usb_reset_resume(struct usb_interface *intf)
{
    if (usb_get_intfdata(intf))
        ath6kl_usb_remove(intf);
    return 0;
}

#else

#define ath6kl_usb_suspend NULL
#define ath6kl_usb_resume NULL
#define ath6kl_usb_reset_resume NULL

#endif

/* table of devices that work with this driver */
static struct usb_device_id ath6kl_usb_ids[] = {
    {USB_DEVICE(0x0cf3, 0x9374)},
    { /* Terminating entry */ },
};

MODULE_DEVICE_TABLE(usb, ath6kl_usb_ids);

static struct usb_driver ath6kl_usb_driver = {
    .name = "ath6kl_usb",
    .probe = ath6kl_usb_probe,
    .suspend = ath6kl_usb_suspend,
    .resume = ath6kl_usb_resume,
    .reset_resume = ath6kl_usb_reset_resume,
    .disconnect = ath6kl_usb_remove,
    .id_table = ath6kl_usb_ids,
    .supports_autosuspend = true,
    .disable_hub_initiated_lpm = 1,
};

static int ath6kl_usb_init(void)
{
    usb_register(&ath6kl_usb_driver);
    return 0;
}

static void ath6kl_usb_exit(void)
{
    usb_deregister(&ath6kl_usb_driver);
}

module_init(ath6kl_usb_init);
module_exit(ath6kl_usb_exit);

MODULE_AUTHOR("Atheros Communications, Inc.");
MODULE_DESCRIPTION("Driver support for Atheros AR600x USB devices");
MODULE_LICENSE("Dual BSD/GPL");
MODULE_FIRMWARE(AR6004_HW_1_0_FIRMWARE_FILE);
MODULE_FIRMWARE(AR6004_HW_1_0_BOARD_DATA_FILE);
MODULE_FIRMWARE(AR6004_HW_1_0_DEFAULT_BOARD_DATA_FILE);
MODULE_FIRMWARE(AR6004_HW_1_1_FIRMWARE_FILE);
MODULE_FIRMWARE(AR6004_HW_1_1_BOARD_DATA_FILE);
MODULE_FIRMWARE(AR6004_HW_1_1_DEFAULT_BOARD_DATA_FILE);
MODULE_FIRMWARE(AR6004_HW_1_2_FIRMWARE_FILE);
MODULE_FIRMWARE(AR6004_HW_1_2_BOARD_DATA_FILE);
MODULE_FIRMWARE(AR6004_HW_1_2_DEFAULT_BOARD_DATA_FILE);