Sync ACPICA with Intel's version 20170831.

[dragonfly.git] / sys / bus / u4b / usb_compat_linux.c

/* $FreeBSD$ */
/*-
 * Copyright (c) 2007 Luigi Rizzo - Universita` di Pisa. All rights reserved.
 * Copyright (c) 2007 Hans Petter Selasky. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/stdint.h>
#include <sys/param.h>
#include <sys/queue.h>
#include <sys/types.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/bus.h>
#include <sys/module.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/condvar.h>
#include <sys/sysctl.h>
#include <sys/unistd.h>
#include <sys/callout.h>
#include <sys/malloc.h>
#include <sys/priv.h>

#include <bus/u4b/usb.h>
#include <bus/u4b/usb_ioctl.h>
#include <bus/u4b/usbdi.h>
#include <bus/u4b/usbdi_util.h>

#define USB_DEBUG_VAR usb_debug

#include <bus/u4b/usb_core.h>
#include <bus/u4b/usb_compat_linux.h>
#include <bus/u4b/usb_process.h>
#include <bus/u4b/usb_device.h>
#include <bus/u4b/usb_util.h>
#include <bus/u4b/usb_busdma.h>
#include <bus/u4b/usb_transfer.h>
#include <bus/u4b/usb_hub.h>
#include <bus/u4b/usb_request.h>
#include <bus/u4b/usb_debug.h>

struct usb_linux_softc {
        LIST_ENTRY(usb_linux_softc) sc_attached_list;

        device_t sc_fbsd_dev;
        struct usb_device *sc_fbsd_udev;
        struct usb_interface *sc_ui;
        struct usb_driver *sc_udrv;
};

/* prototypes */
static device_probe_t usb_linux_probe;
static device_attach_t usb_linux_attach;
static device_detach_t usb_linux_detach;
static device_suspend_t usb_linux_suspend;
static device_resume_t usb_linux_resume;

static usb_callback_t usb_linux_isoc_callback;
static usb_callback_t usb_linux_non_isoc_callback;

static usb_complete_t usb_linux_wait_complete;

static uint16_t usb_max_isoc_frames(struct usb_device *);
static int      usb_start_wait_urb(struct urb *, usb_timeout_t, uint16_t *);
static const struct usb_device_id *usb_linux_lookup_id(
                    const struct usb_device_id *, struct usb_attach_arg *);
static struct   usb_driver *usb_linux_get_usb_driver(struct usb_linux_softc *);
static int      usb_linux_create_usb_device(struct usb_device *, device_t);
static void     usb_linux_cleanup_interface(struct usb_device *,
                    struct usb_interface *);
static void     usb_linux_complete(struct usb_xfer *);
static int      usb_unlink_urb_sub(struct urb *, uint8_t);

/*------------------------------------------------------------------------*
 * FreeBSD USB interface
 *------------------------------------------------------------------------*/

static LIST_HEAD(, usb_linux_softc) usb_linux_attached_list;
static LIST_HEAD(, usb_driver) usb_linux_driver_list;

static device_method_t usb_linux_methods[] = {
        /* Device interface */
        DEVMETHOD(device_probe, usb_linux_probe),
        DEVMETHOD(device_attach, usb_linux_attach),
        DEVMETHOD(device_detach, usb_linux_detach),
        DEVMETHOD(device_suspend, usb_linux_suspend),
        DEVMETHOD(device_resume, usb_linux_resume),

        DEVMETHOD_END
};

static driver_t usb_linux_driver = {
        .name = "usb_linux",
        .methods = usb_linux_methods,
        .size = sizeof(struct usb_linux_softc),
};

static devclass_t usb_linux_devclass;

DRIVER_MODULE(usb_linux, uhub, usb_linux_driver, usb_linux_devclass, NULL, NULL);
MODULE_VERSION(usb_linux, 1);

/*------------------------------------------------------------------------*
 *      usb_linux_lookup_id
 *
 * This functions takes an array of "struct usb_device_id" and tries
 * to match the entries with the information in "struct usb_attach_arg".
 * If it finds a match the matching entry will be returned.
 * Else "NULL" will be returned.
 *------------------------------------------------------------------------*/
static const struct usb_device_id *
usb_linux_lookup_id(const struct usb_device_id *id, struct usb_attach_arg *uaa)
{
        if (id == NULL) {
                goto done;
        }
        /*
         * Keep on matching array entries until we find one with
         * "match_flags" equal to zero, which indicates the end of the
         * array:
         */
        for (; id->match_flags; id++) {

                if ((id->match_flags & USB_DEVICE_ID_MATCH_VENDOR) &&
                    (id->idVendor != uaa->info.idVendor)) {
                        continue;
                }
                if ((id->match_flags & USB_DEVICE_ID_MATCH_PRODUCT) &&
                    (id->idProduct != uaa->info.idProduct)) {
                        continue;
                }
                if ((id->match_flags & USB_DEVICE_ID_MATCH_DEV_LO) &&
                    (id->bcdDevice_lo > uaa->info.bcdDevice)) {
                        continue;
                }
                if ((id->match_flags & USB_DEVICE_ID_MATCH_DEV_HI) &&
                    (id->bcdDevice_hi < uaa->info.bcdDevice)) {
                        continue;
                }
                if ((id->match_flags & USB_DEVICE_ID_MATCH_DEV_CLASS) &&
                    (id->bDeviceClass != uaa->info.bDeviceClass)) {
                        continue;
                }
                if ((id->match_flags & USB_DEVICE_ID_MATCH_DEV_SUBCLASS) &&
                    (id->bDeviceSubClass != uaa->info.bDeviceSubClass)) {
                        continue;
                }
                if ((id->match_flags & USB_DEVICE_ID_MATCH_DEV_PROTOCOL) &&
                    (id->bDeviceProtocol != uaa->info.bDeviceProtocol)) {
                        continue;
                }
                if ((uaa->info.bDeviceClass == 0xFF) &&
                    !(id->match_flags & USB_DEVICE_ID_MATCH_VENDOR) &&
                    (id->match_flags & (USB_DEVICE_ID_MATCH_INT_CLASS |
                    USB_DEVICE_ID_MATCH_INT_SUBCLASS |
                    USB_DEVICE_ID_MATCH_INT_PROTOCOL))) {
                        continue;
                }
                if ((id->match_flags & USB_DEVICE_ID_MATCH_INT_CLASS) &&
                    (id->bInterfaceClass != uaa->info.bInterfaceClass)) {
                        continue;
                }
                if ((id->match_flags & USB_DEVICE_ID_MATCH_INT_SUBCLASS) &&
                    (id->bInterfaceSubClass != uaa->info.bInterfaceSubClass)) {
                        continue;
                }
                if ((id->match_flags & USB_DEVICE_ID_MATCH_INT_PROTOCOL) &&
                    (id->bInterfaceProtocol != uaa->info.bInterfaceProtocol)) {
                        continue;
                }
                /* we found a match! */
                return (id);
        }

done:
        return (NULL);
}

/*------------------------------------------------------------------------*
 *      usb_linux_probe
 *
 * This function is the FreeBSD probe callback. It is called from the
 * FreeBSD USB stack through the "device_probe_and_attach()" function.
 *------------------------------------------------------------------------*/
static int
usb_linux_probe(device_t dev)
{
        struct usb_attach_arg *uaa = device_get_ivars(dev);
        struct usb_driver *udrv;
        int err = ENXIO;

        if (uaa->usb_mode != USB_MODE_HOST) {
                return (ENXIO);
        }
        mtx_lock(&Giant);
        LIST_FOREACH(udrv, &usb_linux_driver_list, linux_driver_list) {
                if (usb_linux_lookup_id(udrv->id_table, uaa)) {
                        err = 0;
                        break;
                }
        }
        mtx_unlock(&Giant);

        return (err);
}

/*------------------------------------------------------------------------*
 *      usb_linux_get_usb_driver
 *
 * This function returns the pointer to the "struct usb_driver" where
 * the Linux USB device driver "struct usb_device_id" match was found.
 * We apply a lock before reading out the pointer to avoid races.
 *------------------------------------------------------------------------*/
static struct usb_driver *
usb_linux_get_usb_driver(struct usb_linux_softc *sc)
{
        struct usb_driver *udrv;

        mtx_lock(&Giant);
        udrv = sc->sc_udrv;
        mtx_unlock(&Giant);
        return (udrv);
}

/*------------------------------------------------------------------------*
 *      usb_linux_attach
 *
 * This function is the FreeBSD attach callback. It is called from the
 * FreeBSD USB stack through the "device_probe_and_attach()" function.
 * This function is called when "usb_linux_probe()" returns zero.
 *------------------------------------------------------------------------*/
static int
usb_linux_attach(device_t dev)
{
        struct usb_attach_arg *uaa = device_get_ivars(dev);
        struct usb_linux_softc *sc = device_get_softc(dev);
        struct usb_driver *udrv;
        const struct usb_device_id *id = NULL;

        mtx_lock(&Giant);
        LIST_FOREACH(udrv, &usb_linux_driver_list, linux_driver_list) {
                id = usb_linux_lookup_id(udrv->id_table, uaa);
                if (id)
                        break;
        }
        mtx_unlock(&Giant);

        if (id == NULL) {
                return (ENXIO);
        }
        if (usb_linux_create_usb_device(uaa->device, dev) != 0)
                return (ENOMEM);
        device_set_usb_desc(dev);

        sc->sc_fbsd_udev = uaa->device;
        sc->sc_fbsd_dev = dev;
        sc->sc_udrv = udrv;
        sc->sc_ui = usb_ifnum_to_if(uaa->device, uaa->info.bIfaceNum);
        if (sc->sc_ui == NULL) {
                return (EINVAL);
        }
        if (udrv->probe) {
                if ((udrv->probe) (sc->sc_ui, id)) {
                        return (ENXIO);
                }
        }
        mtx_lock(&Giant);
        LIST_INSERT_HEAD(&usb_linux_attached_list, sc, sc_attached_list);
        mtx_unlock(&Giant);

        /* success */
        return (0);
}

/*------------------------------------------------------------------------*
 *      usb_linux_detach
 *
 * This function is the FreeBSD detach callback. It is called from the
 * FreeBSD USB stack through the "device_detach()" function.
 *------------------------------------------------------------------------*/
static int
usb_linux_detach(device_t dev)
{
        struct usb_linux_softc *sc = device_get_softc(dev);
        struct usb_driver *udrv = NULL;

        mtx_lock(&Giant);
        if (sc->sc_attached_list.le_prev) {
                LIST_REMOVE(sc, sc_attached_list);
                sc->sc_attached_list.le_prev = NULL;
                udrv = sc->sc_udrv;
                sc->sc_udrv = NULL;
        }
        mtx_unlock(&Giant);

        if (udrv && udrv->disconnect) {
                (udrv->disconnect) (sc->sc_ui);
        }
        /*
         * Make sure that we free all FreeBSD USB transfers belonging to
         * this Linux "usb_interface", hence they will most likely not be
         * needed any more.
         */
        usb_linux_cleanup_interface(sc->sc_fbsd_udev, sc->sc_ui);
        return (0);
}

/*------------------------------------------------------------------------*
 *      usb_linux_suspend
 *
 * This function is the FreeBSD suspend callback. Usually it does nothing.
 *------------------------------------------------------------------------*/
static int
usb_linux_suspend(device_t dev)
{
        struct usb_linux_softc *sc = device_get_softc(dev);
        struct usb_driver *udrv = usb_linux_get_usb_driver(sc);
        int err;

        if (udrv && udrv->suspend) {
                err = (udrv->suspend) (sc->sc_ui, 0);
        }
        return (0);
}

/*------------------------------------------------------------------------*
 *      usb_linux_resume
 *
 * This function is the FreeBSD resume callback. Usually it does nothing.
 *------------------------------------------------------------------------*/
static int
usb_linux_resume(device_t dev)
{
        struct usb_linux_softc *sc = device_get_softc(dev);
        struct usb_driver *udrv = usb_linux_get_usb_driver(sc);
        int err;

        if (udrv && udrv->resume) {
                err = (udrv->resume) (sc->sc_ui);
        }
        return (0);
}

/*------------------------------------------------------------------------*
 * Linux emulation layer
 *------------------------------------------------------------------------*/

/*------------------------------------------------------------------------*
 *      usb_max_isoc_frames
 *
 * The following function returns the maximum number of isochronous
 * frames that we support per URB. It is not part of the Linux USB API.
 *------------------------------------------------------------------------*/
static uint16_t
usb_max_isoc_frames(struct usb_device *dev)
{
        ;                               /* indent fix */
        switch (usbd_get_speed(dev)) {
        case USB_SPEED_LOW:
        case USB_SPEED_FULL:
                return (USB_MAX_FULL_SPEED_ISOC_FRAMES);
        default:
                return (USB_MAX_HIGH_SPEED_ISOC_FRAMES);
        }
}

/*------------------------------------------------------------------------*
 *      usb_submit_urb
 *
 * This function is used to queue an URB after that it has been
 * initialized. If it returns non-zero, it means that the URB was not
 * queued.
 *------------------------------------------------------------------------*/
int
usb_submit_urb(struct urb *urb, uint16_t mem_flags)
{
        struct usb_host_endpoint *uhe;
        uint8_t do_unlock;
        int err;

        if (urb == NULL)
                return (-EINVAL);

        do_unlock = mtx_owned(&Giant) ? 0 : 1;
        if (do_unlock)
                mtx_lock(&Giant);

        if (urb->endpoint == NULL) {
                err = -EINVAL;
                goto done;
        }

        /*
         * Check to see if the urb is in the process of being killed
         * and stop a urb that is in the process of being killed from
         * being re-submitted (e.g. from its completion callback
         * function).
         */
        if (urb->kill_count != 0) {
                err = -EPERM;
                goto done;
        }

        uhe = urb->endpoint;

        /*
         * Check that we have got a FreeBSD USB transfer that will dequeue
         * the URB structure and do the real transfer. If there are no USB
         * transfers, then we return an error.
         */
        if (uhe->bsd_xfer[0] ||
            uhe->bsd_xfer[1]) {
                /* we are ready! */

                TAILQ_INSERT_TAIL(&uhe->bsd_urb_list, urb, bsd_urb_list);

                urb->status = -EINPROGRESS;

                usbd_transfer_start(uhe->bsd_xfer[0]);
                usbd_transfer_start(uhe->bsd_xfer[1]);
                err = 0;
        } else {
                /* no pipes have been setup yet! */
                urb->status = -EINVAL;
                err = -EINVAL;
        }
done:
        if (do_unlock)
                mtx_unlock(&Giant);
        return (err);
}

/*------------------------------------------------------------------------*
 *      usb_unlink_urb
 *
 * This function is used to stop an URB after that it is been
 * submitted, but before the "complete" callback has been called. On
 *------------------------------------------------------------------------*/
int
usb_unlink_urb(struct urb *urb)
{
        return (usb_unlink_urb_sub(urb, 0));
}

static void
usb_unlink_bsd(struct usb_xfer *xfer,
    struct urb *urb, uint8_t drain)
{
        if (xfer == NULL)
                return;
        if (!usbd_transfer_pending(xfer))
                return;
        if (xfer->priv_fifo == (void *)urb) {
                if (drain) {
                        mtx_unlock(&Giant);
                        usbd_transfer_drain(xfer);
                        mtx_lock(&Giant);
                } else {
                        usbd_transfer_stop(xfer);
                }
                usbd_transfer_start(xfer);
        }
}

static int
usb_unlink_urb_sub(struct urb *urb, uint8_t drain)
{
        struct usb_host_endpoint *uhe;
        uint16_t x;
        uint8_t do_unlock;
        int err;

        if (urb == NULL)
                return (-EINVAL);

        do_unlock = mtx_owned(&Giant) ? 0 : 1;
        if (do_unlock)
                mtx_lock(&Giant);
        if (drain)
                urb->kill_count++;

        if (urb->endpoint == NULL) {
                err = -EINVAL;
                goto done;
        }
        uhe = urb->endpoint;

        if (urb->bsd_urb_list.tqe_prev) {

                /* not started yet, just remove it from the queue */
                TAILQ_REMOVE(&uhe->bsd_urb_list, urb, bsd_urb_list);
                urb->bsd_urb_list.tqe_prev = NULL;
                urb->status = -ECONNRESET;
                urb->actual_length = 0;

                for (x = 0; x < urb->number_of_packets; x++) {
                        urb->iso_frame_desc[x].actual_length = 0;
                }

                if (urb->complete) {
                        (urb->complete) (urb);
                }
        } else {

                /*
                 * If the URB is not on the URB list, then check if one of
                 * the FreeBSD USB transfer are processing the current URB.
                 * If so, re-start that transfer, which will lead to the
                 * termination of that URB:
                 */
                usb_unlink_bsd(uhe->bsd_xfer[0], urb, drain);
                usb_unlink_bsd(uhe->bsd_xfer[1], urb, drain);
        }
        err = 0;
done:
        if (drain)
                urb->kill_count--;
        if (do_unlock)
                mtx_unlock(&Giant);
        return (err);
}

/*------------------------------------------------------------------------*
 *      usb_clear_halt
 *
 * This function must always be used to clear the stall. Stall is when
 * an USB endpoint returns a stall message to the USB host controller.
 * Until the stall is cleared, no data can be transferred.
 *------------------------------------------------------------------------*/
int
usb_clear_halt(struct usb_device *dev, struct usb_host_endpoint *uhe)
{
        struct usb_config cfg[1];
        struct usb_endpoint *ep;
        uint8_t type;
        uint8_t addr;

        if (uhe == NULL)
                return (-EINVAL);

        type = uhe->desc.bmAttributes & UE_XFERTYPE;
        addr = uhe->desc.bEndpointAddress;

        memset(cfg, 0, sizeof(cfg));

        cfg[0].type = type;
        cfg[0].endpoint = addr & UE_ADDR;
        cfg[0].direction = addr & (UE_DIR_OUT | UE_DIR_IN);

        ep = usbd_get_endpoint(dev, uhe->bsd_iface_index, cfg);
        if (ep == NULL)
                return (-EINVAL);

        usbd_clear_data_toggle(dev, ep);

        return (usb_control_msg(dev, &dev->ep0,
            UR_CLEAR_FEATURE, UT_WRITE_ENDPOINT,
            UF_ENDPOINT_HALT, addr, NULL, 0, 1000));
}

/*------------------------------------------------------------------------*
 *      usb_start_wait_urb
 *
 * This is an internal function that is used to perform synchronous
 * Linux USB transfers.
 *------------------------------------------------------------------------*/
static int
usb_start_wait_urb(struct urb *urb, usb_timeout_t timeout, uint16_t *p_actlen)
{
        int err;
        uint8_t do_unlock;

        /* you must have a timeout! */
        if (timeout == 0) {
                timeout = 1;
        }
        urb->complete = &usb_linux_wait_complete;
        urb->timeout = timeout;
        urb->transfer_flags |= URB_WAIT_WAKEUP;
        urb->transfer_flags &= ~URB_IS_SLEEPING;

        do_unlock = mtx_owned(&Giant) ? 0 : 1;
        if (do_unlock)
                mtx_lock(&Giant);
        err = usb_submit_urb(urb, 0);
        if (err)
                goto done;

        /*
         * the URB might have completed before we get here, so check that by
         * using some flags!
         */
        while (urb->transfer_flags & URB_WAIT_WAKEUP) {
                urb->transfer_flags |= URB_IS_SLEEPING;
                cv_wait(&urb->cv_wait, &Giant);
                urb->transfer_flags &= ~URB_IS_SLEEPING;
        }

        err = urb->status;

done:
        if (do_unlock)
                mtx_unlock(&Giant);
        if (p_actlen != NULL) {
                if (err)
                        *p_actlen = 0;
                else
                        *p_actlen = urb->actual_length;
        }
        return (err);
}

/*------------------------------------------------------------------------*
 *      usb_control_msg
 *
 * The following function performs a control transfer sequence one any
 * control, bulk or interrupt endpoint, specified by "uhe". A control
 * transfer means that you transfer an 8-byte header first followed by
 * a data-phase as indicated by the 8-byte header. The "timeout" is
 * given in milliseconds.
 *
 * Return values:
 *   0: Success
 * < 0: Failure
 * > 0: Acutal length
 *------------------------------------------------------------------------*/
int
usb_control_msg(struct usb_device *dev, struct usb_host_endpoint *uhe,
    uint8_t request, uint8_t requesttype,
    uint16_t value, uint16_t index, void *data,
    uint16_t size, usb_timeout_t timeout)
{
        struct usb_device_request req;
        struct urb *urb;
        int err;
        uint16_t actlen;
        uint8_t type;
        uint8_t addr;

        req.bmRequestType = requesttype;
        req.bRequest = request;
        USETW(req.wValue, value);
        USETW(req.wIndex, index);
        USETW(req.wLength, size);

        if (uhe == NULL) {
                return (-EINVAL);
        }
        type = (uhe->desc.bmAttributes & UE_XFERTYPE);
        addr = (uhe->desc.bEndpointAddress & UE_ADDR);

        if (type != UE_CONTROL) {
                return (-EINVAL);
        }
        if (addr == 0) {
                /*
                 * The FreeBSD USB stack supports standard control
                 * transfers on control endpoint zero:
                 */
                err = usbd_do_request_flags(dev,
                    NULL, &req, data, USB_SHORT_XFER_OK,
                    &actlen, timeout);
                if (err) {
                        err = -EPIPE;
                } else {
                        err = actlen;
                }
                return (err);
        }
        if (dev->flags.usb_mode != USB_MODE_HOST) {
                /* not supported */
                return (-EINVAL);
        }
        err = usb_setup_endpoint(dev, uhe, 1 /* dummy */ );

        /*
         * NOTE: we need to allocate real memory here so that we don't
         * transfer data to/from the stack!
         *
         * 0xFFFF is a FreeBSD specific magic value.
         */
        urb = usb_alloc_urb(0xFFFF, size);
        if (urb == NULL)
                return (-ENOMEM);

        urb->dev = dev;
        urb->endpoint = uhe;

        memcpy(urb->setup_packet, &req, sizeof(req));

        if (size && (!(req.bmRequestType & UT_READ))) {
                /* move the data to a real buffer */
                memcpy(USB_ADD_BYTES(urb->setup_packet, sizeof(req)),
                    data, size);
        }
        err = usb_start_wait_urb(urb, timeout, &actlen);

        if (req.bmRequestType & UT_READ) {
                if (actlen) {
                        bcopy(USB_ADD_BYTES(urb->setup_packet,
                            sizeof(req)), data, actlen);
                }
        }
        usb_free_urb(urb);

        if (err == 0) {
                err = actlen;
        }
        return (err);
}

/*------------------------------------------------------------------------*
 *      usb_set_interface
 *
 * The following function will select which alternate setting of an
 * USB interface you plan to use. By default alternate setting with
 * index zero is selected. Note that "iface_no" is not the interface
 * index, but rather the value of "bInterfaceNumber".
 *------------------------------------------------------------------------*/
int
usb_set_interface(struct usb_device *dev, uint8_t iface_no, uint8_t alt_index)
{
        struct usb_interface *p_ui = usb_ifnum_to_if(dev, iface_no);
        int err;

        if (p_ui == NULL)
                return (-EINVAL);
        if (alt_index >= p_ui->num_altsetting)
                return (-EINVAL);
        usb_linux_cleanup_interface(dev, p_ui);
        err = -usbd_set_alt_interface_index(dev,
            p_ui->bsd_iface_index, alt_index);
        if (err == 0) {
                p_ui->cur_altsetting = p_ui->altsetting + alt_index;
        }
        return (err);
}

/*------------------------------------------------------------------------*
 *      usb_setup_endpoint
 *
 * The following function is an extension to the Linux USB API that
 * allows you to set a maximum buffer size for a given USB endpoint.
 * The maximum buffer size is per URB. If you don't call this function
 * to set a maximum buffer size, the endpoint will not be functional.
 * Note that for isochronous endpoints the maximum buffer size must be
 * a non-zero dummy, hence this function will base the maximum buffer
 * size on "wMaxPacketSize".
 *------------------------------------------------------------------------*/
int
usb_setup_endpoint(struct usb_device *dev,
    struct usb_host_endpoint *uhe, usb_size_t bufsize)
{
        struct usb_config cfg[2];
        uint8_t type = uhe->desc.bmAttributes & UE_XFERTYPE;
        uint8_t addr = uhe->desc.bEndpointAddress;

        if (uhe->fbsd_buf_size == bufsize) {
                /* optimize */
                return (0);
        }
        usbd_transfer_unsetup(uhe->bsd_xfer, 2);

        uhe->fbsd_buf_size = bufsize;

        if (bufsize == 0) {
                return (0);
        }
        memset(cfg, 0, sizeof(cfg));

        if (type == UE_ISOCHRONOUS) {

                /*
                 * Isochronous transfers are special in that they don't fit
                 * into the BULK/INTR/CONTROL transfer model.
                 */

                cfg[0].type = type;
                cfg[0].endpoint = addr & UE_ADDR;
                cfg[0].direction = addr & (UE_DIR_OUT | UE_DIR_IN);
                cfg[0].callback = &usb_linux_isoc_callback;
                cfg[0].bufsize = 0;     /* use wMaxPacketSize */
                cfg[0].frames = usb_max_isoc_frames(dev);
                cfg[0].flags.proxy_buffer = 1;
#if 0
                /*
                 * The Linux USB API allows non back-to-back
                 * isochronous frames which we do not support. If the
                 * isochronous frames are not back-to-back we need to
                 * do a copy, and then we need a buffer for
                 * that. Enable this at your own risk.
                 */
                cfg[0].flags.ext_buffer = 1;
#endif
                cfg[0].flags.short_xfer_ok = 1;

                bcopy(cfg, cfg + 1, sizeof(*cfg));

                /* Allocate and setup two generic FreeBSD USB transfers */

                if (usbd_transfer_setup(dev, &uhe->bsd_iface_index,
                    uhe->bsd_xfer, cfg, 2, uhe, &Giant)) {
                        return (-EINVAL);
                }
        } else {
                if (bufsize > (1 << 22)) {
                        /* limit buffer size */
                        bufsize = (1 << 22);
                }
                /* Allocate and setup one generic FreeBSD USB transfer */

                cfg[0].type = type;
                cfg[0].endpoint = addr & UE_ADDR;
                cfg[0].direction = addr & (UE_DIR_OUT | UE_DIR_IN);
                cfg[0].callback = &usb_linux_non_isoc_callback;
                cfg[0].bufsize = bufsize;
                cfg[0].flags.ext_buffer = 1;    /* enable zero-copy */
                cfg[0].flags.proxy_buffer = 1;
                cfg[0].flags.short_xfer_ok = 1;

                if (usbd_transfer_setup(dev, &uhe->bsd_iface_index,
                    uhe->bsd_xfer, cfg, 1, uhe, &Giant)) {
                        return (-EINVAL);
                }
        }
        return (0);
}

/*------------------------------------------------------------------------*
 *      usb_linux_create_usb_device
 *
 * The following function is used to build up a per USB device
 * structure tree, that mimics the Linux one. The root structure
 * is returned by this function.
 *------------------------------------------------------------------------*/
static int
usb_linux_create_usb_device(struct usb_device *udev, device_t dev)
{
        struct usb_config_descriptor *cd = usbd_get_config_descriptor(udev);
        struct usb_descriptor *desc;
        struct usb_interface_descriptor *id;
        struct usb_endpoint_descriptor *ed;
        struct usb_interface *p_ui = NULL;
        struct usb_host_interface *p_uhi = NULL;
        struct usb_host_endpoint *p_uhe = NULL;
        usb_size_t size;
        uint16_t niface_total;
        uint16_t nedesc;
        uint16_t iface_no_curr;
        uint16_t iface_index;
        uint8_t pass;
        uint8_t iface_no;

        /*
         * We do two passes. One pass for computing necessary memory size
         * and one pass to initialize all the allocated memory structures.
         */
        for (pass = 0; pass < 2; pass++) {

                iface_no_curr = 0 - 1;
                niface_total = 0;
                iface_index = 0;
                nedesc = 0;
                desc = NULL;

                /*
                 * Iterate over all the USB descriptors. Use the USB config
                 * descriptor pointer provided by the FreeBSD USB stack.
                 */
                while ((desc = usb_desc_foreach(cd, desc))) {

                        /*
                         * Build up a tree according to the descriptors we
                         * find:
                         */
                        switch (desc->bDescriptorType) {
                        case UDESC_DEVICE:
                                break;

                        case UDESC_ENDPOINT:
                                ed = (void *)desc;
                                if ((ed->bLength < sizeof(*ed)) ||
                                    (iface_index == 0))
                                        break;
                                if (p_uhe) {
                                        bcopy(ed, &p_uhe->desc, sizeof(p_uhe->desc));
                                        p_uhe->bsd_iface_index = iface_index - 1;
                                        TAILQ_INIT(&p_uhe->bsd_urb_list);
                                        p_uhe++;
                                }
                                if (p_uhi) {
                                        (p_uhi - 1)->desc.bNumEndpoints++;
                                }
                                nedesc++;
                                break;

                        case UDESC_INTERFACE:
                                id = (void *)desc;
                                if (id->bLength < sizeof(*id))
                                        break;
                                if (p_uhi) {
                                        bcopy(id, &p_uhi->desc, sizeof(p_uhi->desc));
                                        p_uhi->desc.bNumEndpoints = 0;
                                        p_uhi->endpoint = p_uhe;
                                        p_uhi->string = "";
                                        p_uhi->bsd_iface_index = iface_index;
                                        p_uhi++;
                                }
                                iface_no = id->bInterfaceNumber;
                                niface_total++;
                                if (iface_no_curr != iface_no) {
                                        if (p_ui) {
                                                p_ui->altsetting = p_uhi - 1;
                                                p_ui->cur_altsetting = p_uhi - 1;
                                                p_ui->num_altsetting = 1;
                                                p_ui->bsd_iface_index = iface_index;
                                                p_ui->linux_udev = udev;
                                                p_ui++;
                                        }
                                        iface_no_curr = iface_no;
                                        iface_index++;
                                } else {
                                        if (p_ui) {
                                                (p_ui - 1)->num_altsetting++;
                                        }
                                }
                                break;

                        default:
                                break;
                        }
                }

                if (pass == 0) {

                        size = (sizeof(*p_uhe) * nedesc) +
                            (sizeof(*p_ui) * iface_index) +
                            (sizeof(*p_uhi) * niface_total);

                        p_uhe = malloc(size, M_USBDEV, M_WAITOK | M_ZERO);
                        p_ui = (void *)(p_uhe + nedesc);
                        p_uhi = (void *)(p_ui + iface_index);

                        udev->linux_iface_start = p_ui;
                        udev->linux_iface_end = p_ui + iface_index;
                        udev->linux_endpoint_start = p_uhe;
                        udev->linux_endpoint_end = p_uhe + nedesc;
                        udev->devnum = device_get_unit(dev);
                        bcopy(&udev->ddesc, &udev->descriptor,
                            sizeof(udev->descriptor));
                        bcopy(udev->ctrl_ep.edesc, &udev->ep0.desc,
                            sizeof(udev->ep0.desc));
                }
        }
        return (0);
}

/*------------------------------------------------------------------------*
 *      usb_alloc_urb
 *
 * This function should always be used when you allocate an URB for
 * use with the USB Linux stack. In case of an isochronous transfer
 * you must specifiy the maximum number of "iso_packets" which you
 * plan to transfer per URB. This function is always blocking, and
 * "mem_flags" are not regarded like on Linux.
 *------------------------------------------------------------------------*/
struct urb *
usb_alloc_urb(uint16_t iso_packets, uint16_t mem_flags)
{
        struct urb *urb;
        usb_size_t size;

        if (iso_packets == 0xFFFF) {
                /*
                 * FreeBSD specific magic value to ask for control transfer
                 * memory allocation:
                 */
                size = sizeof(*urb) + sizeof(struct usb_device_request) + mem_flags;
        } else {
                size = sizeof(*urb) + (iso_packets * sizeof(urb->iso_frame_desc[0]));
        }

        urb = malloc(size, M_USBDEV, M_WAITOK | M_ZERO);
        if (urb) {

                cv_init(&urb->cv_wait, "URBWAIT");
                if (iso_packets == 0xFFFF) {
                        urb->setup_packet = (void *)(urb + 1);
                        urb->transfer_buffer = (void *)(urb->setup_packet +
                            sizeof(struct usb_device_request));
                } else {
                        urb->number_of_packets = iso_packets;
                }
        }
        return (urb);
}

/*------------------------------------------------------------------------*
 *      usb_find_host_endpoint
 *
 * The following function will return the Linux USB host endpoint
 * structure that matches the given endpoint type and endpoint
 * value. If no match is found, NULL is returned. This function is not
 * part of the Linux USB API and is only used internally.
 *------------------------------------------------------------------------*/
struct usb_host_endpoint *
usb_find_host_endpoint(struct usb_device *dev, uint8_t type, uint8_t ep)
{
        struct usb_host_endpoint *uhe;
        struct usb_host_endpoint *uhe_end;
        struct usb_host_interface *uhi;
        struct usb_interface *ui;
        uint8_t ea;
        uint8_t at;
        uint8_t mask;

        if (dev == NULL) {
                return (NULL);
        }
        if (type == UE_CONTROL) {
                mask = UE_ADDR;
        } else {
                mask = (UE_DIR_IN | UE_DIR_OUT | UE_ADDR);
        }

        ep &= mask;

        /*
         * Iterate over all the interfaces searching the selected alternate
         * setting only, and all belonging endpoints.
         */
        for (ui = dev->linux_iface_start;
            ui != dev->linux_iface_end;
            ui++) {
                uhi = ui->cur_altsetting;
                if (uhi) {
                        uhe_end = uhi->endpoint + uhi->desc.bNumEndpoints;
                        for (uhe = uhi->endpoint;
                            uhe != uhe_end;
                            uhe++) {
                                ea = uhe->desc.bEndpointAddress;
                                at = uhe->desc.bmAttributes;

                                if (((ea & mask) == ep) &&
                                    ((at & UE_XFERTYPE) == type)) {
                                        return (uhe);
                                }
                        }
                }
        }

        if ((type == UE_CONTROL) && ((ep & UE_ADDR) == 0)) {
                return (&dev->ep0);
        }
        return (NULL);
}

/*------------------------------------------------------------------------*
 *      usb_altnum_to_altsetting
 *
 * The following function returns a pointer to an alternate setting by
 * index given a "usb_interface" pointer. If the alternate setting by
 * index does not exist, NULL is returned. And alternate setting is a
 * variant of an interface, but usually with slightly different
 * characteristics.
 *------------------------------------------------------------------------*/
struct usb_host_interface *
usb_altnum_to_altsetting(const struct usb_interface *intf, uint8_t alt_index)
{
        if (alt_index >= intf->num_altsetting) {
                return (NULL);
        }
        return (intf->altsetting + alt_index);
}

/*------------------------------------------------------------------------*
 *      usb_ifnum_to_if
 *
 * The following function searches up an USB interface by
 * "bInterfaceNumber". If no match is found, NULL is returned.
 *------------------------------------------------------------------------*/
struct usb_interface *
usb_ifnum_to_if(struct usb_device *dev, uint8_t iface_no)
{
        struct usb_interface *p_ui;

        for (p_ui = dev->linux_iface_start;
            p_ui != dev->linux_iface_end;
            p_ui++) {
                if ((p_ui->num_altsetting > 0) &&
                    (p_ui->altsetting->desc.bInterfaceNumber == iface_no)) {
                        return (p_ui);
                }
        }
        return (NULL);
}

/*------------------------------------------------------------------------*
 *      usb_buffer_alloc
 *------------------------------------------------------------------------*/
void   *
usb_buffer_alloc(struct usb_device *dev, usb_size_t size, uint16_t mem_flags, uint8_t *dma_addr)
{
        return (malloc(size, M_USBDEV, M_WAITOK | M_ZERO));
}

/*------------------------------------------------------------------------*
 *      usbd_get_intfdata
 *------------------------------------------------------------------------*/
void   *
usbd_get_intfdata(struct usb_interface *intf)
{
        return (intf->bsd_priv_sc);
}

/*------------------------------------------------------------------------*
 *      usb_linux_register
 *
 * The following function is used by the "USB_DRIVER_EXPORT()" macro,
 * and is used to register a Linux USB driver, so that its
 * "usb_device_id" structures gets searched a probe time. This
 * function is not part of the Linux USB API, and is for internal use
 * only.
 *------------------------------------------------------------------------*/
void
usb_linux_register(void *arg)
{
        struct usb_driver *drv = arg;

        mtx_lock(&Giant);
        LIST_INSERT_HEAD(&usb_linux_driver_list, drv, linux_driver_list);
        mtx_unlock(&Giant);

        usb_needs_explore_all();
}

/*------------------------------------------------------------------------*
 *      usb_linux_deregister
 *
 * The following function is used by the "USB_DRIVER_EXPORT()" macro,
 * and is used to deregister a Linux USB driver. This function will
 * ensure that all driver instances belonging to the Linux USB device
 * driver in question, gets detached before the driver is
 * unloaded. This function is not part of the Linux USB API, and is
 * for internal use only.
 *------------------------------------------------------------------------*/
void
usb_linux_deregister(void *arg)
{
        struct usb_driver *drv = arg;
        struct usb_linux_softc *sc;

repeat:
        mtx_lock(&Giant);
        LIST_FOREACH(sc, &usb_linux_attached_list, sc_attached_list) {
                if (sc->sc_udrv == drv) {
                        mtx_unlock(&Giant);
                        device_detach(sc->sc_fbsd_dev);
                        goto repeat;
                }
        }
        LIST_REMOVE(drv, linux_driver_list);
        mtx_unlock(&Giant);
}

/*------------------------------------------------------------------------*
 *      usb_linux_free_device
 *
 * The following function is only used by the FreeBSD USB stack, to
 * cleanup and free memory after that a Linux USB device was attached.
 *------------------------------------------------------------------------*/
void
usb_linux_free_device(struct usb_device *dev)
{
        struct usb_host_endpoint *uhe;
        struct usb_host_endpoint *uhe_end;
        int err;

        uhe = dev->linux_endpoint_start;
        uhe_end = dev->linux_endpoint_end;
        while (uhe != uhe_end) {
                err = usb_setup_endpoint(dev, uhe, 0);
                uhe++;
        }
        err = usb_setup_endpoint(dev, &dev->ep0, 0);
        free(dev->linux_endpoint_start, M_USBDEV);
}

/*------------------------------------------------------------------------*
 *      usb_buffer_free
 *------------------------------------------------------------------------*/
void
usb_buffer_free(struct usb_device *dev, usb_size_t size,
    void *addr, uint8_t dma_addr)
{
        free(addr, M_USBDEV);
}

/*------------------------------------------------------------------------*
 *      usb_free_urb
 *------------------------------------------------------------------------*/
void
usb_free_urb(struct urb *urb)
{
        if (urb == NULL) {
                return;
        }
        /* make sure that the current URB is not active */
        usb_kill_urb(urb);

        /* destroy condition variable */
        cv_destroy(&urb->cv_wait);

        /* just free it */
        free(urb, M_USBDEV);
}

/*------------------------------------------------------------------------*
 *      usb_init_urb
 *
 * The following function can be used to initialize a custom URB. It
 * is not recommended to use this function. Use "usb_alloc_urb()"
 * instead.
 *------------------------------------------------------------------------*/
void
usb_init_urb(struct urb *urb)
{
        if (urb == NULL) {
                return;
        }
        memset(urb, 0, sizeof(*urb));
}

/*------------------------------------------------------------------------*
 *      usb_kill_urb
 *------------------------------------------------------------------------*/
void
usb_kill_urb(struct urb *urb)
{
        usb_unlink_urb_sub(urb, 1);
}

/*------------------------------------------------------------------------*
 *      usb_set_intfdata
 *
 * The following function sets the per Linux USB interface private
 * data pointer. It is used by most Linux USB device drivers.
 *------------------------------------------------------------------------*/
void
usb_set_intfdata(struct usb_interface *intf, void *data)
{
        intf->bsd_priv_sc = data;
}

/*------------------------------------------------------------------------*
 *      usb_linux_cleanup_interface
 *
 * The following function will release all FreeBSD USB transfers
 * associated with a Linux USB interface. It is for internal use only.
 *------------------------------------------------------------------------*/
static void
usb_linux_cleanup_interface(struct usb_device *dev, struct usb_interface *iface)
{
        struct usb_host_interface *uhi;
        struct usb_host_interface *uhi_end;
        struct usb_host_endpoint *uhe;
        struct usb_host_endpoint *uhe_end;
        int err;

        uhi = iface->altsetting;
        uhi_end = iface->altsetting + iface->num_altsetting;
        while (uhi != uhi_end) {
                uhe = uhi->endpoint;
                uhe_end = uhi->endpoint + uhi->desc.bNumEndpoints;
                while (uhe != uhe_end) {
                        err = usb_setup_endpoint(dev, uhe, 0);
                        uhe++;
                }
                uhi++;
        }
}

/*------------------------------------------------------------------------*
 *      usb_linux_wait_complete
 *
 * The following function is used by "usb_start_wait_urb()" to wake it
 * up, when an USB transfer has finished.
 *------------------------------------------------------------------------*/
static void
usb_linux_wait_complete(struct urb *urb)
{
        if (urb->transfer_flags & URB_IS_SLEEPING) {
                cv_signal(&urb->cv_wait);
        }
        urb->transfer_flags &= ~URB_WAIT_WAKEUP;
}

/*------------------------------------------------------------------------*
 *      usb_linux_complete
 *------------------------------------------------------------------------*/
static void
usb_linux_complete(struct usb_xfer *xfer)
{
        struct urb *urb;

        urb = usbd_xfer_get_priv(xfer);
        usbd_xfer_set_priv(xfer, NULL);
        if (urb->complete) {
                (urb->complete) (urb);
        }
}

/*------------------------------------------------------------------------*
 *      usb_linux_isoc_callback
 *
 * The following is the FreeBSD isochronous USB callback. Isochronous
 * frames are USB packets transferred 1000 or 8000 times per second,
 * depending on whether a full- or high- speed USB transfer is
 * used.
 *------------------------------------------------------------------------*/
static void
usb_linux_isoc_callback(struct usb_xfer *xfer, usb_error_t error)
{
        usb_frlength_t max_frame = xfer->max_frame_size;
        usb_frlength_t offset;
        usb_frcount_t x;
        struct urb *urb = usbd_xfer_get_priv(xfer);
        struct usb_host_endpoint *uhe = usbd_xfer_softc(xfer);
        struct usb_iso_packet_descriptor *uipd;

        DPRINTF("\n");

        switch (USB_GET_STATE(xfer)) {
        case USB_ST_TRANSFERRED:

                if (urb->bsd_isread) {

                        /* copy in data with regard to the URB */

                        offset = 0;

                        for (x = 0; x < urb->number_of_packets; x++) {
                                uipd = urb->iso_frame_desc + x;
                                if (uipd->length > xfer->frlengths[x]) {
                                        if (urb->transfer_flags & URB_SHORT_NOT_OK) {
                                                /* XXX should be EREMOTEIO */
                                                uipd->status = -EPIPE;
                                        } else {
                                                uipd->status = 0;
                                        }
                                } else {
                                        uipd->status = 0;
                                }
                                uipd->actual_length = xfer->frlengths[x];
                                if (!xfer->flags.ext_buffer) {
                                        usbd_copy_out(xfer->frbuffers, offset,
                                            USB_ADD_BYTES(urb->transfer_buffer,
                                            uipd->offset), uipd->actual_length);
                                }
                                offset += max_frame;
                        }
                } else {
                        for (x = 0; x < urb->number_of_packets; x++) {
                                uipd = urb->iso_frame_desc + x;
                                uipd->actual_length = xfer->frlengths[x];
                                uipd->status = 0;
                        }
                }

                urb->actual_length = xfer->actlen;

                /* check for short transfer */
                if (xfer->actlen < xfer->sumlen) {
                        /* short transfer */
                        if (urb->transfer_flags & URB_SHORT_NOT_OK) {
                                /* XXX should be EREMOTEIO */
                                urb->status = -EPIPE;
                        } else {
                                urb->status = 0;
                        }
                } else {
                        /* success */
                        urb->status = 0;
                }

                /* call callback */
                usb_linux_complete(xfer);

        case USB_ST_SETUP:
tr_setup:

                if (xfer->priv_fifo == NULL) {

                        /* get next transfer */
                        urb = TAILQ_FIRST(&uhe->bsd_urb_list);
                        if (urb == NULL) {
                                /* nothing to do */
                                return;
                        }
                        TAILQ_REMOVE(&uhe->bsd_urb_list, urb, bsd_urb_list);
                        urb->bsd_urb_list.tqe_prev = NULL;

                        x = xfer->max_frame_count;
                        if (urb->number_of_packets > x) {
                                /* XXX simply truncate the transfer */
                                urb->number_of_packets = x;
                        }
                } else {
                        DPRINTF("Already got a transfer\n");

                        /* already got a transfer (should not happen) */
                        urb = usbd_xfer_get_priv(xfer);
                }

                urb->bsd_isread = (uhe->desc.bEndpointAddress & UE_DIR_IN) ? 1 : 0;

                if (xfer->flags.ext_buffer) {
                        /* set virtual address to load */
                        usbd_xfer_set_frame_data(xfer, 0, urb->transfer_buffer, 0);
                }
                if (!(urb->bsd_isread)) {

                        /* copy out data with regard to the URB */

                        offset = 0;

                        for (x = 0; x < urb->number_of_packets; x++) {
                                uipd = urb->iso_frame_desc + x;
                                usbd_xfer_set_frame_len(xfer, x, uipd->length);
                                if (!xfer->flags.ext_buffer) {
                                        usbd_copy_in(xfer->frbuffers, offset,
                                            USB_ADD_BYTES(urb->transfer_buffer,
                                            uipd->offset), uipd->length);
                                }
                                offset += uipd->length;
                        }
                } else {

                        /*
                         * compute the transfer length into the "offset"
                         * variable
                         */

                        offset = urb->number_of_packets * max_frame;

                        /* setup "frlengths" array */

                        for (x = 0; x < urb->number_of_packets; x++) {
                                uipd = urb->iso_frame_desc + x;
                                usbd_xfer_set_frame_len(xfer, x, max_frame);
                        }
                }
                usbd_xfer_set_priv(xfer, urb);
                xfer->flags.force_short_xfer = 0;
                xfer->timeout = urb->timeout;
                xfer->nframes = urb->number_of_packets;
                usbd_transfer_submit(xfer);
                return;

        default:                        /* Error */
                if (xfer->error == USB_ERR_CANCELLED) {
                        urb->status = -ECONNRESET;
                } else {
                        urb->status = -EPIPE;   /* stalled */
                }

                /* Set zero for "actual_length" */
                urb->actual_length = 0;

                /* Set zero for "actual_length" */
                for (x = 0; x < urb->number_of_packets; x++) {
                        urb->iso_frame_desc[x].actual_length = 0;
                        urb->iso_frame_desc[x].status = urb->status;
                }

                /* call callback */
                usb_linux_complete(xfer);

                if (xfer->error == USB_ERR_CANCELLED) {
                        /* we need to return in this case */
                        return;
                }
                goto tr_setup;

        }
}

/*------------------------------------------------------------------------*
 *      usb_linux_non_isoc_callback
 *
 * The following is the FreeBSD BULK/INTERRUPT and CONTROL USB
 * callback. It dequeues Linux USB stack compatible URB's, transforms
 * the URB fields into a FreeBSD USB transfer, and defragments the USB
 * transfer as required. When the transfer is complete the "complete"
 * callback is called.
 *------------------------------------------------------------------------*/
static void
usb_linux_non_isoc_callback(struct usb_xfer *xfer, usb_error_t error)
{
        enum {
                REQ_SIZE = sizeof(struct usb_device_request)
        };
        struct urb *urb = usbd_xfer_get_priv(xfer);
        struct usb_host_endpoint *uhe = usbd_xfer_softc(xfer);
        uint8_t *ptr;
        usb_frlength_t max_bulk = usbd_xfer_max_len(xfer);
        uint8_t data_frame = xfer->flags_int.control_xfr ? 1 : 0;

        DPRINTF("\n");

        switch (USB_GET_STATE(xfer)) {
        case USB_ST_TRANSFERRED:

                if (xfer->flags_int.control_xfr) {

                        /* don't transfer the setup packet again: */

                        usbd_xfer_set_frame_len(xfer, 0, 0);
                }
                if (urb->bsd_isread && (!xfer->flags.ext_buffer)) {
                        /* copy in data with regard to the URB */
                        usbd_copy_out(xfer->frbuffers + data_frame, 0,
                            urb->bsd_data_ptr, xfer->frlengths[data_frame]);
                }
                urb->bsd_length_rem -= xfer->frlengths[data_frame];
                urb->bsd_data_ptr += xfer->frlengths[data_frame];
                urb->actual_length += xfer->frlengths[data_frame];

                /* check for short transfer */
                if (xfer->actlen < xfer->sumlen) {
                        urb->bsd_length_rem = 0;

                        /* short transfer */
                        if (urb->transfer_flags & URB_SHORT_NOT_OK) {
                                urb->status = -EPIPE;
                        } else {
                                urb->status = 0;
                        }
                } else {
                        /* check remainder */
                        if (urb->bsd_length_rem > 0) {
                                goto setup_bulk;
                        }
                        /* success */
                        urb->status = 0;
                }

                /* call callback */
                usb_linux_complete(xfer);

        case USB_ST_SETUP:
tr_setup:
                /* get next transfer */
                urb = TAILQ_FIRST(&uhe->bsd_urb_list);
                if (urb == NULL) {
                        /* nothing to do */
                        return;
                }
                TAILQ_REMOVE(&uhe->bsd_urb_list, urb, bsd_urb_list);
                urb->bsd_urb_list.tqe_prev = NULL;

                usbd_xfer_set_priv(xfer, urb);
                xfer->flags.force_short_xfer = 0;
                xfer->timeout = urb->timeout;

                if (xfer->flags_int.control_xfr) {

                        /*
                         * USB control transfers need special handling.
                         * First copy in the header, then copy in data!
                         */
                        if (!xfer->flags.ext_buffer) {
                                usbd_copy_in(xfer->frbuffers, 0,
                                    urb->setup_packet, REQ_SIZE);
                                usbd_xfer_set_frame_len(xfer, 0, REQ_SIZE);
                        } else {
                                /* set virtual address to load */
                                usbd_xfer_set_frame_data(xfer, 0,
                                    urb->setup_packet, REQ_SIZE);
                        }

                        ptr = urb->setup_packet;

                        /* setup data transfer direction and length */
                        urb->bsd_isread = (ptr[0] & UT_READ) ? 1 : 0;
                        urb->bsd_length_rem = ptr[6] | (ptr[7] << 8);

                } else {

                        /* setup data transfer direction */

                        urb->bsd_length_rem = urb->transfer_buffer_length;
                        urb->bsd_isread = (uhe->desc.bEndpointAddress &
                            UE_DIR_IN) ? 1 : 0;
                }

                urb->bsd_data_ptr = urb->transfer_buffer;
                urb->actual_length = 0;

setup_bulk:
                if (max_bulk > urb->bsd_length_rem) {
                        max_bulk = urb->bsd_length_rem;
                }
                /* check if we need to force a short transfer */

                if ((max_bulk == urb->bsd_length_rem) &&
                    (urb->transfer_flags & URB_ZERO_PACKET) &&
                    (!xfer->flags_int.control_xfr)) {
                        xfer->flags.force_short_xfer = 1;
                }
                /* check if we need to copy in data */

                if (xfer->flags.ext_buffer) {
                        /* set virtual address to load */
                        usbd_xfer_set_frame_data(xfer, data_frame,
                            urb->bsd_data_ptr, max_bulk);
                } else if (!urb->bsd_isread) {
                        /* copy out data with regard to the URB */
                        usbd_copy_in(xfer->frbuffers + data_frame, 0,
                            urb->bsd_data_ptr, max_bulk);
                        usbd_xfer_set_frame_len(xfer, data_frame, max_bulk);
                }
                if (xfer->flags_int.control_xfr) {
                        if (max_bulk > 0) {
                                xfer->nframes = 2;
                        } else {
                                xfer->nframes = 1;
                        }
                } else {
                        xfer->nframes = 1;
                }
                usbd_transfer_submit(xfer);
                return;

        default:
                if (xfer->error == USB_ERR_CANCELLED) {
                        urb->status = -ECONNRESET;
                } else {
                        urb->status = -EPIPE;
                }

                /* Set zero for "actual_length" */
                urb->actual_length = 0;

                /* call callback */
                usb_linux_complete(xfer);

                if (xfer->error == USB_ERR_CANCELLED) {
                        /* we need to return in this case */
                        return;
                }
                goto tr_setup;
        }
}

/*------------------------------------------------------------------------*
 *      usb_fill_bulk_urb
 *------------------------------------------------------------------------*/
void
usb_fill_bulk_urb(struct urb *urb, struct usb_device *udev,
    struct usb_host_endpoint *uhe, void *buf,
    int length, usb_complete_t callback, void *arg)
{
        urb->dev = udev;
        urb->endpoint = uhe;
        urb->transfer_buffer = buf;
        urb->transfer_buffer_length = length;
        urb->complete = callback;
        urb->context = arg;
}

/*------------------------------------------------------------------------*
 *      usb_bulk_msg
 *
 * NOTE: This function can also be used for interrupt endpoints!
 *
 * Return values:
 *    0: Success
 * Else: Failure
 *------------------------------------------------------------------------*/
int
usb_bulk_msg(struct usb_device *udev, struct usb_host_endpoint *uhe,
    void *data, int len, uint16_t *pactlen, usb_timeout_t timeout)
{
        struct urb *urb;
        int err;

        if (uhe == NULL)
                return (-EINVAL);
        if (len < 0)
                return (-EINVAL);

        err = usb_setup_endpoint(udev, uhe, 4096 /* bytes */);
        if (err)
                return (err);

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

        usb_fill_bulk_urb(urb, udev, uhe, data, len,
            usb_linux_wait_complete, NULL);

        err = usb_start_wait_urb(urb, timeout, pactlen);

        usb_free_urb(urb);

        return (err);
}