/*
 * dummy_hcd.c -- Dummy/Loopback USB host and device emulator driver.
 *
 * Maintainer: Alan Stern <stern@rowland.harvard.edu>
 *
 * Copyright (C) 2003 David Brownell
 * Copyright (C) 2003-2005 Alan Stern
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */


/*
 * This exposes a device side "USB gadget" API, driven by requests to a
 * Linux-USB host controller driver.  USB traffic is simulated; there's
 * no need for USB hardware.  Use this with two other drivers:
 *
 *  - Gadget driver, responding to requests (slave);
 *  - Host-side device driver, as already familiar in Linux.
 *
 * Having this all in one kernel can help some stages of development,
 * bypassing some hardware (and driver) issues.  UML could help too.
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/delay.h>
#include <linux/ioport.h>
#include <linux/slab.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/timer.h>
#include <linux/list.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <linux/usb.h>
#include <linux/usb/gadget.h>

#include <asm/byteorder.h>
#include <asm/io.h>
#include <asm/irq.h>
#include <asm/system.h>
#include <asm/unaligned.h>


#include "../core/hcd.h"


#define DRIVER_DESC     "USB Host+Gadget Emulator"
#define DRIVER_VERSION  "02 May 2005"

#define POWER_BUDGET    500     /* in mA; use 8 for low-power port testing */

static const char       driver_name [] = "dummy_hcd";
static const char       driver_desc [] = "USB Host+Gadget Emulator";

static const char       gadget_name [] = "dummy_udc";

MODULE_DESCRIPTION (DRIVER_DESC);
MODULE_AUTHOR ("David Brownell");
MODULE_LICENSE ("GPL");

/*-------------------------------------------------------------------------*/

/* gadget side driver data structres */
struct dummy_ep {
        struct list_head                queue;
        unsigned long                   last_io;        /* jiffies timestamp */
        struct usb_gadget               *gadget;
        const struct usb_endpoint_descriptor *desc;
        struct usb_ep                   ep;
        unsigned                        halted : 1;
        unsigned                        already_seen : 1;
        unsigned                        setup_stage : 1;
};

struct dummy_request {
        struct list_head                queue;          /* ep's requests */
        struct usb_request              req;
};

static inline struct dummy_ep *usb_ep_to_dummy_ep (struct usb_ep *_ep)
{
        return container_of (_ep, struct dummy_ep, ep);
}

static inline struct dummy_request *usb_request_to_dummy_request
                (struct usb_request *_req)
{
        return container_of (_req, struct dummy_request, req);
}

/*-------------------------------------------------------------------------*/

/*
 * Every device has ep0 for control requests, plus up to 30 more endpoints,
 * in one of two types:
 *
 *   - Configurable:  direction (in/out), type (bulk, iso, etc), and endpoint
 *     number can be changed.  Names like "ep-a" are used for this type.
 *
 *   - Fixed Function:  in other cases.  some characteristics may be mutable;
 *     that'd be hardware-specific.  Names like "ep12out-bulk" are used.
 *
 * Gadget drivers are responsible for not setting up conflicting endpoint
 * configurations, illegal or unsupported packet lengths, and so on.
 */

static const char ep0name [] = "ep0";

static const char *const ep_name [] = {
        ep0name,                                /* everyone has ep0 */

        /* act like a net2280: high speed, six configurable endpoints */
        "ep-a", "ep-b", "ep-c", "ep-d", "ep-e", "ep-f",

        /* or like pxa250: fifteen fixed function endpoints */
        "ep1in-bulk", "ep2out-bulk", "ep3in-iso", "ep4out-iso", "ep5in-int",
        "ep6in-bulk", "ep7out-bulk", "ep8in-iso", "ep9out-iso", "ep10in-int",
        "ep11in-bulk", "ep12out-bulk", "ep13in-iso", "ep14out-iso",
                "ep15in-int",

        /* or like sa1100: two fixed function endpoints */
        "ep1out-bulk", "ep2in-bulk",
};
#define DUMMY_ENDPOINTS ARRAY_SIZE(ep_name)

/*-------------------------------------------------------------------------*/

#define FIFO_SIZE               64

struct urbp {
        struct urb              *urb;
        struct list_head        urbp_list;
};


enum dummy_rh_state {
        DUMMY_RH_RESET,
        DUMMY_RH_SUSPENDED,
        DUMMY_RH_RUNNING
};

struct dummy {
        spinlock_t                      lock;

        /*
         * SLAVE/GADGET side support
         */
        struct dummy_ep                 ep [DUMMY_ENDPOINTS];
        int                             address;
        struct usb_gadget               gadget;
        struct usb_gadget_driver        *driver;
        struct dummy_request            fifo_req;
        u8                              fifo_buf [FIFO_SIZE];
        u16                             devstatus;
        unsigned                        udc_suspended:1;
        unsigned                        pullup:1;
        unsigned                        active:1;
        unsigned                        old_active:1;

        /*
         * MASTER/HOST side support
         */
        enum dummy_rh_state             rh_state;
        struct timer_list               timer;
        u32                             port_status;
        u32                             old_status;
        unsigned                        resuming:1;
        unsigned long                   re_timeout;

        struct usb_device               *udev;
        struct list_head                urbp_list;
};

static inline struct dummy *hcd_to_dummy (struct usb_hcd *hcd)
{
        return (struct dummy *) (hcd->hcd_priv);
}

static inline struct usb_hcd *dummy_to_hcd (struct dummy *dum)
{
        return container_of((void *) dum, struct usb_hcd, hcd_priv);
}

static inline struct device *dummy_dev (struct dummy *dum)
{
        return dummy_to_hcd(dum)->self.controller;
}

static inline struct device *udc_dev (struct dummy *dum)
{
        return dum->gadget.dev.parent;
}

static inline struct dummy *ep_to_dummy (struct dummy_ep *ep)
{
        return container_of (ep->gadget, struct dummy, gadget);
}

static inline struct dummy *gadget_to_dummy (struct usb_gadget *gadget)
{
        return container_of (gadget, struct dummy, gadget);
}

static inline struct dummy *gadget_dev_to_dummy (struct device *dev)
{
        return container_of (dev, struct dummy, gadget.dev);
}

static struct dummy                     *the_controller;

/*-------------------------------------------------------------------------*/

/* SLAVE/GADGET SIDE UTILITY ROUTINES */

/* called with spinlock held */
static void nuke (struct dummy *dum, struct dummy_ep *ep)
{
        while (!list_empty (&ep->queue)) {
                struct dummy_request    *req;

                req = list_entry (ep->queue.next, struct dummy_request, queue);
                list_del_init (&req->queue);
                req->req.status = -ESHUTDOWN;

                spin_unlock (&dum->lock);
                req->req.complete (&ep->ep, &req->req);
                spin_lock (&dum->lock);
        }
}

/* caller must hold lock */
static void
stop_activity (struct dummy *dum)
{
        struct dummy_ep *ep;

        /* prevent any more requests */
        dum->address = 0;

        /* The timer is left running so that outstanding URBs can fail */

        /* nuke any pending requests first, so driver i/o is quiesced */
        list_for_each_entry (ep, &dum->gadget.ep_list, ep.ep_list)
                nuke (dum, ep);

        /* driver now does any non-usb quiescing necessary */
}

/* caller must hold lock */
static void
set_link_state (struct dummy *dum)
{
        dum->active = 0;
        if ((dum->port_status & USB_PORT_STAT_POWER) == 0)
                dum->port_status = 0;

        /* UDC suspend must cause a disconnect */
        else if (!dum->pullup || dum->udc_suspended) {
                dum->port_status &= ~(USB_PORT_STAT_CONNECTION |
                                        USB_PORT_STAT_ENABLE |
                                        USB_PORT_STAT_LOW_SPEED |
                                        USB_PORT_STAT_HIGH_SPEED |
                                        USB_PORT_STAT_SUSPEND);
                if ((dum->old_status & USB_PORT_STAT_CONNECTION) != 0)
                        dum->port_status |= (USB_PORT_STAT_C_CONNECTION << 16);
        } else {
                dum->port_status |= USB_PORT_STAT_CONNECTION;
                if ((dum->old_status & USB_PORT_STAT_CONNECTION) == 0)
                        dum->port_status |= (USB_PORT_STAT_C_CONNECTION << 16);
                if ((dum->port_status & USB_PORT_STAT_ENABLE) == 0)
                        dum->port_status &= ~USB_PORT_STAT_SUSPEND;
                else if ((dum->port_status & USB_PORT_STAT_SUSPEND) == 0 &&
                                dum->rh_state != DUMMY_RH_SUSPENDED)
                        dum->active = 1;
        }

        if ((dum->port_status & USB_PORT_STAT_ENABLE) == 0 || dum->active)
                dum->resuming = 0;

        if ((dum->port_status & USB_PORT_STAT_CONNECTION) == 0 ||
                        (dum->port_status & USB_PORT_STAT_RESET) != 0) {
                if ((dum->old_status & USB_PORT_STAT_CONNECTION) != 0 &&
                                (dum->old_status & USB_PORT_STAT_RESET) == 0 &&
                                dum->driver) {
                        stop_activity (dum);
                        spin_unlock (&dum->lock);
                        dum->driver->disconnect (&dum->gadget);
                        spin_lock (&dum->lock);
                }
        } else if (dum->active != dum->old_active) {
                if (dum->old_active && dum->driver->suspend) {
                        spin_unlock (&dum->lock);
                        dum->driver->suspend (&dum->gadget);
                        spin_lock (&dum->lock);
                } else if (!dum->old_active && dum->driver->resume) {
                        spin_unlock (&dum->lock);
                        dum->driver->resume (&dum->gadget);
                        spin_lock (&dum->lock);
                }
        }

        dum->old_status = dum->port_status;
        dum->old_active = dum->active;
}

/*-------------------------------------------------------------------------*/

/* SLAVE/GADGET SIDE DRIVER
 *
 * This only tracks gadget state.  All the work is done when the host
 * side tries some (emulated) i/o operation.  Real device controller
 * drivers would do real i/o using dma, fifos, irqs, timers, etc.
 */

#define is_enabled(dum) \
        (dum->port_status & USB_PORT_STAT_ENABLE)

static int
dummy_enable (struct usb_ep *_ep, const struct usb_endpoint_descriptor *desc)
{
        struct dummy            *dum;
        struct dummy_ep         *ep;
        unsigned                max;
        int                     retval;

        ep = usb_ep_to_dummy_ep (_ep);
        if (!_ep || !desc || ep->desc || _ep->name == ep0name
                        || desc->bDescriptorType != USB_DT_ENDPOINT)
                return -EINVAL;
        dum = ep_to_dummy (ep);
        if (!dum->driver || !is_enabled (dum))
                return -ESHUTDOWN;
        max = le16_to_cpu(desc->wMaxPacketSize) & 0x3ff;

        /* drivers must not request bad settings, since lower levels
         * (hardware or its drivers) may not check.  some endpoints
         * can't do iso, many have maxpacket limitations, etc.
         *
         * since this "hardware" driver is here to help debugging, we
         * have some extra sanity checks.  (there could be more though,
         * especially for "ep9out" style fixed function ones.)
         */
        retval = -EINVAL;
        switch (desc->bmAttributes & 0x03) {
        case USB_ENDPOINT_XFER_BULK:
                if (strstr (ep->ep.name, "-iso")
                                || strstr (ep->ep.name, "-int")) {
                        goto done;
                }
                switch (dum->gadget.speed) {
                case USB_SPEED_HIGH:
                        if (max == 512)
                                break;
                        goto done;
                case USB_SPEED_FULL:
                        if (max == 8 || max == 16 || max == 32 || max == 64)
                                /* we'll fake any legal size */
                                break;
                        /* save a return statement */
                default:
                        goto done;
                }
                break;
        case USB_ENDPOINT_XFER_INT:
                if (strstr (ep->ep.name, "-iso")) /* bulk is ok */
                        goto done;
                /* real hardware might not handle all packet sizes */
                switch (dum->gadget.speed) {
                case USB_SPEED_HIGH:
                        if (max <= 1024)
                                break;
                        /* save a return statement */
                case USB_SPEED_FULL:
                        if (max <= 64)
                                break;
                        /* save a return statement */
                default:
                        if (max <= 8)
                                break;
                        goto done;
                }
                break;
        case USB_ENDPOINT_XFER_ISOC:
                if (strstr (ep->ep.name, "-bulk")
                                || strstr (ep->ep.name, "-int"))
                        goto done;
                /* real hardware might not handle all packet sizes */
                switch (dum->gadget.speed) {
                case USB_SPEED_HIGH:
                        if (max <= 1024)
                                break;
                        /* save a return statement */
                case USB_SPEED_FULL:
                        if (max <= 1023)
                                break;
                        /* save a return statement */
                default:
                        goto done;
                }
                break;
        default:
                /* few chips support control except on ep0 */
                goto done;
        }

        _ep->maxpacket = max;
        ep->desc = desc;

        dev_dbg (udc_dev(dum), "enabled %s (ep%d%s-%s) maxpacket %d\n",
                _ep->name,
                desc->bEndpointAddress & 0x0f,
                (desc->bEndpointAddress & USB_DIR_IN) ? "in" : "out",
                ({ char *val;
                 switch (desc->bmAttributes & 0x03) {
                 case USB_ENDPOINT_XFER_BULK: val = "bulk"; break;
                 case USB_ENDPOINT_XFER_ISOC: val = "iso"; break;
                 case USB_ENDPOINT_XFER_INT: val = "intr"; break;
                 default: val = "ctrl"; break;
                 }; val; }),
                max);

        /* at this point real hardware should be NAKing transfers
         * to that endpoint, until a buffer is queued to it.
         */
        retval = 0;
done:
        return retval;
}

static int dummy_disable (struct usb_ep *_ep)
{
        struct dummy_ep         *ep;
        struct dummy            *dum;
        unsigned long           flags;
        int                     retval;

        ep = usb_ep_to_dummy_ep (_ep);
        if (!_ep || !ep->desc || _ep->name == ep0name)
                return -EINVAL;
        dum = ep_to_dummy (ep);

        spin_lock_irqsave (&dum->lock, flags);
        ep->desc = NULL;
        retval = 0;
        nuke (dum, ep);
        spin_unlock_irqrestore (&dum->lock, flags);

        dev_dbg (udc_dev(dum), "disabled %s\n", _ep->name);
        return retval;
}

static struct usb_request *
dummy_alloc_request (struct usb_ep *_ep, gfp_t mem_flags)
{
        struct dummy_ep         *ep;
        struct dummy_request    *req;

        if (!_ep)
                return NULL;
        ep = usb_ep_to_dummy_ep (_ep);

        req = kzalloc(sizeof(*req), mem_flags);
        if (!req)
                return NULL;
        INIT_LIST_HEAD (&req->queue);
        return &req->req;
}

static void
dummy_free_request (struct usb_ep *_ep, struct usb_request *_req)
{
        struct dummy_ep         *ep;
        struct dummy_request    *req;

        ep = usb_ep_to_dummy_ep (_ep);
        if (!ep || !_req || (!ep->desc && _ep->name != ep0name))
                return;

        req = usb_request_to_dummy_request (_req);
        WARN_ON (!list_empty (&req->queue));
        kfree (req);
}

static void
fifo_complete (struct usb_ep *ep, struct usb_request *req)
{
}

static int
dummy_queue (struct usb_ep *_ep, struct usb_request *_req,
                gfp_t mem_flags)
{
        struct dummy_ep         *ep;
        struct dummy_request    *req;
        struct dummy            *dum;
        unsigned long           flags;

        req = usb_request_to_dummy_request (_req);
        if (!_req || !list_empty (&req->queue) || !_req->complete)
                return -EINVAL;

        ep = usb_ep_to_dummy_ep (_ep);
        if (!_ep || (!ep->desc && _ep->name != ep0name))
                return -EINVAL;

        dum = ep_to_dummy (ep);
        if (!dum->driver || !is_enabled (dum))
                return -ESHUTDOWN;

#if 0
        dev_dbg (udc_dev(dum), "ep %p queue req %p to %s, len %d buf %p\n",
                        ep, _req, _ep->name, _req->length, _req->buf);
#endif

        _req->status = -EINPROGRESS;
        _req->actual = 0;
        spin_lock_irqsave (&dum->lock, flags);

        /* implement an emulated single-request FIFO */
        if (ep->desc && (ep->desc->bEndpointAddress & USB_DIR_IN) &&
                        list_empty (&dum->fifo_req.queue) &&
                        list_empty (&ep->queue) &&
                        _req->length <= FIFO_SIZE) {
                req = &dum->fifo_req;
                req->req = *_req;
                req->req.buf = dum->fifo_buf;
                memcpy (dum->fifo_buf, _req->buf, _req->length);
                req->req.context = dum;
                req->req.complete = fifo_complete;

                list_add_tail(&req->queue, &ep->queue);
                spin_unlock (&dum->lock);
                _req->actual = _req->length;
                _req->status = 0;
                _req->complete (_ep, _req);
                spin_lock (&dum->lock);
        }  else
                list_add_tail(&req->queue, &ep->queue);
        spin_unlock_irqrestore (&dum->lock, flags);

        /* real hardware would likely enable transfers here, in case
         * it'd been left NAKing.
         */
        return 0;
}

static int dummy_dequeue (struct usb_ep *_ep, struct usb_request *_req)
{
        struct dummy_ep         *ep;
        struct dummy            *dum;
        int                     retval = -EINVAL;
        unsigned long           flags;
        struct dummy_request    *req = NULL;

        if (!_ep || !_req)
                return retval;
        ep = usb_ep_to_dummy_ep (_ep);
        dum = ep_to_dummy (ep);

        if (!dum->driver)
                return -ESHUTDOWN;

        local_irq_save (flags);
        spin_lock (&dum->lock);
        list_for_each_entry (req, &ep->queue, queue) {
                if (&req->req == _req) {
                        list_del_init (&req->queue);
                        _req->status = -ECONNRESET;
                        retval = 0;
                        break;
                }
        }
        spin_unlock (&dum->lock);

        if (retval == 0) {
                dev_dbg (udc_dev(dum),
                                "dequeued req %p from %s, len %d buf %p\n",
                                req, _ep->name, _req->length, _req->buf);
                _req->complete (_ep, _req);
        }
        local_irq_restore (flags);
        return retval;
}

static int
dummy_set_halt (struct usb_ep *_ep, int value)
{
        struct dummy_ep         *ep;
        struct dummy            *dum;

        if (!_ep)
                return -EINVAL;
        ep = usb_ep_to_dummy_ep (_ep);
        dum = ep_to_dummy (ep);
        if (!dum->driver)
                return -ESHUTDOWN;
        if (!value)
                ep->halted = 0;
        else if (ep->desc && (ep->desc->bEndpointAddress & USB_DIR_IN) &&
                        !list_empty (&ep->queue))
                return -EAGAIN;
        else
                ep->halted = 1;
        /* FIXME clear emulated data toggle too */
        return 0;
}

static const struct usb_ep_ops dummy_ep_ops = {
        .enable         = dummy_enable,
        .disable        = dummy_disable,

        .alloc_request  = dummy_alloc_request,
        .free_request   = dummy_free_request,

        .queue          = dummy_queue,
        .dequeue        = dummy_dequeue,

        .set_halt       = dummy_set_halt,
};

/*-------------------------------------------------------------------------*/

/* there are both host and device side versions of this call ... */
static int dummy_g_get_frame (struct usb_gadget *_gadget)
{
        struct timeval  tv;

        do_gettimeofday (&tv);
        return tv.tv_usec / 1000;
}

static int dummy_wakeup (struct usb_gadget *_gadget)
{
        struct dummy    *dum;

        dum = gadget_to_dummy (_gadget);
        if (!(dum->devstatus &  ( (1 << USB_DEVICE_B_HNP_ENABLE)
                                | (1 << USB_DEVICE_REMOTE_WAKEUP))))
                return -EINVAL;
        if ((dum->port_status & USB_PORT_STAT_CONNECTION) == 0)
                return -ENOLINK;
        if ((dum->port_status & USB_PORT_STAT_SUSPEND) == 0 &&
                         dum->rh_state != DUMMY_RH_SUSPENDED)
                return -EIO;

        /* FIXME: What if the root hub is suspended but the port isn't? */

        /* hub notices our request, issues downstream resume, etc */
        dum->resuming = 1;
        dum->re_timeout = jiffies + msecs_to_jiffies(20);
        mod_timer (&dummy_to_hcd (dum)->rh_timer, dum->re_timeout);
        return 0;
}

static int dummy_set_selfpowered (struct usb_gadget *_gadget, int value)
{
        struct dummy    *dum;

        dum = gadget_to_dummy (_gadget);
        if (value)
                dum->devstatus |= (1 << USB_DEVICE_SELF_POWERED);
        else
                dum->devstatus &= ~(1 << USB_DEVICE_SELF_POWERED);
        return 0;
}

static int dummy_pullup (struct usb_gadget *_gadget, int value)
{
        struct dummy    *dum;
        unsigned long   flags;

        dum = gadget_to_dummy (_gadget);
        spin_lock_irqsave (&dum->lock, flags);
        dum->pullup = (value != 0);
        set_link_state (dum);
        spin_unlock_irqrestore (&dum->lock, flags);

        usb_hcd_poll_rh_status (dummy_to_hcd (dum));
        return 0;
}

static const struct usb_gadget_ops dummy_ops = {
        .get_frame      = dummy_g_get_frame,
        .wakeup         = dummy_wakeup,
        .set_selfpowered = dummy_set_selfpowered,
        .pullup         = dummy_pullup,
};

/*-------------------------------------------------------------------------*/

/* "function" sysfs attribute */
static ssize_t
show_function (struct device *dev, struct device_attribute *attr, char *buf)
{
        struct dummy    *dum = gadget_dev_to_dummy (dev);

        if (!dum->driver || !dum->driver->function)
                return 0;
        return scnprintf (buf, PAGE_SIZE, "%s\n", dum->driver->function);
}
static DEVICE_ATTR (function, S_IRUGO, show_function, NULL);

/*-------------------------------------------------------------------------*/

/*
 * Driver registration/unregistration.
 *
 * This is basically hardware-specific; there's usually only one real USB
 * device (not host) controller since that's how USB devices are intended
 * to work.  So most implementations of these api calls will rely on the
 * fact that only one driver will ever bind to the hardware.  But curious
 * hardware can be built with discrete components, so the gadget API doesn't
 * require that assumption.
 *
 * For this emulator, it might be convenient to create a usb slave device
 * for each driver that registers:  just add to a big root hub.
 */

int
usb_gadget_register_driver (struct usb_gadget_driver *driver)
{
        struct dummy    *dum = the_controller;
        int             retval, i;

        if (!dum)
                return -EINVAL;
        if (dum->driver)
                return -EBUSY;
        if (!driver->bind || !driver->setup
                        || driver->speed == USB_SPEED_UNKNOWN)
                return -EINVAL;

        /*
         * SLAVE side init ... the layer above hardware, which
         * can't enumerate without help from the driver we're binding.
         */

        dum->devstatus = 0;

        INIT_LIST_HEAD (&dum->gadget.ep_list);
        for (i = 0; i < DUMMY_ENDPOINTS; i++) {
                struct dummy_ep *ep = &dum->ep [i];

                if (!ep_name [i])
                        break;
                ep->ep.name = ep_name [i];
                ep->ep.ops = &dummy_ep_ops;
                list_add_tail (&ep->ep.ep_list, &dum->gadget.ep_list);
                ep->halted = ep->already_seen = ep->setup_stage = 0;
                ep->ep.maxpacket = ~0;
                ep->last_io = jiffies;
                ep->gadget = &dum->gadget;
                ep->desc = NULL;
                INIT_LIST_HEAD (&ep->queue);
        }

        dum->gadget.ep0 = &dum->ep [0].ep;
        dum->ep [0].ep.maxpacket = 64;
        list_del_init (&dum->ep [0].ep.ep_list);
        INIT_LIST_HEAD(&dum->fifo_req.queue);

        driver->driver.bus = NULL;
        dum->driver = driver;
        dum->gadget.dev.driver = &driver->driver;
        dev_dbg (udc_dev(dum), "binding gadget driver '%s'\n",
                        driver->driver.name);
        retval = driver->bind(&dum->gadget);
        if (retval) {
                dum->driver = NULL;
                dum->gadget.dev.driver = NULL;
                return retval;
        }

        /* khubd will enumerate this in a while */
        spin_lock_irq (&dum->lock);
        dum->pullup = 1;
        set_link_state (dum);
        spin_unlock_irq (&dum->lock);

        usb_hcd_poll_rh_status (dummy_to_hcd (dum));
        return 0;
}
EXPORT_SYMBOL (usb_gadget_register_driver);

int
usb_gadget_unregister_driver (struct usb_gadget_driver *driver)
{
        struct dummy    *dum = the_controller;
        unsigned long   flags;

        if (!dum)
                return -ENODEV;
        if (!driver || driver != dum->driver || !driver->unbind)
                return -EINVAL;

        dev_dbg (udc_dev(dum), "unregister gadget driver '%s'\n",
                        driver->driver.name);

        spin_lock_irqsave (&dum->lock, flags);
        dum->pullup = 0;
        set_link_state (dum);
        spin_unlock_irqrestore (&dum->lock, flags);

        driver->unbind (&dum->gadget);
        dum->gadget.dev.driver = NULL;
        dum->driver = NULL;

        spin_lock_irqsave (&dum->lock, flags);
        dum->pullup = 0;
        set_link_state (dum);
        spin_unlock_irqrestore (&dum->lock, flags);

        usb_hcd_poll_rh_status (dummy_to_hcd (dum));
        return 0;
}
EXPORT_SYMBOL (usb_gadget_unregister_driver);

#undef is_enabled

/* just declare this in any driver that really need it */
extern int net2280_set_fifo_mode (struct usb_gadget *gadget, int mode);

int net2280_set_fifo_mode (struct usb_gadget *gadget, int mode)
{
        return -ENOSYS;
}
EXPORT_SYMBOL (net2280_set_fifo_mode);


/* The gadget structure is stored inside the hcd structure and will be
 * released along with it. */
static void
dummy_gadget_release (struct device *dev)
{
        struct dummy    *dum = gadget_dev_to_dummy (dev);

        usb_put_hcd (dummy_to_hcd (dum));
}

static int dummy_udc_probe (struct platform_device *pdev)
{
        struct dummy    *dum = the_controller;
        int             rc;

        dum->gadget.name = gadget_name;
        dum->gadget.ops = &dummy_ops;
        dum->gadget.is_dualspeed = 1;

        /* maybe claim OTG support, though we won't complete HNP */
        dum->gadget.is_otg = (dummy_to_hcd(dum)->self.otg_port != 0);

        dev_set_name(&dum->gadget.dev, "gadget");
        dum->gadget.dev.parent = &pdev->dev;
        dum->gadget.dev.release = dummy_gadget_release;
        rc = device_register (&dum->gadget.dev);
        if (rc < 0)
                return rc;

        usb_get_hcd (dummy_to_hcd (dum));

        platform_set_drvdata (pdev, dum);
        rc = device_create_file (&dum->gadget.dev, &dev_attr_function);
        if (rc < 0)
                device_unregister (&dum->gadget.dev);
        return rc;
}

static int dummy_udc_remove (struct platform_device *pdev)
{
        struct dummy    *dum = platform_get_drvdata (pdev);

        platform_set_drvdata (pdev, NULL);
        device_remove_file (&dum->gadget.dev, &dev_attr_function);
        device_unregister (&dum->gadget.dev);
        return 0;
}

static int dummy_udc_suspend (struct platform_device *pdev, pm_message_t state)
{
        struct dummy    *dum = platform_get_drvdata(pdev);

        dev_dbg (&pdev->dev, "%s\n", __func__);
        spin_lock_irq (&dum->lock);
        dum->udc_suspended = 1;
        set_link_state (dum);
        spin_unlock_irq (&dum->lock);

        usb_hcd_poll_rh_status (dummy_to_hcd (dum));
        return 0;
}

static int dummy_udc_resume (struct platform_device *pdev)
{
        struct dummy    *dum = platform_get_drvdata(pdev);

        dev_dbg (&pdev->dev, "%s\n", __func__);
        spin_lock_irq (&dum->lock);
        dum->udc_suspended = 0;
        set_link_state (dum);
        spin_unlock_irq (&dum->lock);

        usb_hcd_poll_rh_status (dummy_to_hcd (dum));
        return 0;
}

static struct platform_driver dummy_udc_driver = {
        .probe          = dummy_udc_probe,
        .remove         = dummy_udc_remove,
        .suspend        = dummy_udc_suspend,
        .resume         = dummy_udc_resume,
        .driver         = {
                .name   = (char *) gadget_name,
                .owner  = THIS_MODULE,
        },
};

/*-------------------------------------------------------------------------*/

/* MASTER/HOST SIDE DRIVER
 *
 * this uses the hcd framework to hook up to host side drivers.
 * its root hub will only have one device, otherwise it acts like
 * a normal host controller.
 *
 * when urbs are queued, they're just stuck on a list that we
 * scan in a timer callback.  that callback connects writes from
 * the host with reads from the device, and so on, based on the
 * usb 2.0 rules.
 */

static int dummy_urb_enqueue (
        struct usb_hcd                  *hcd,
        struct urb                      *urb,
        gfp_t                           mem_flags
) {
        struct dummy    *dum;
        struct urbp     *urbp;
        unsigned long   flags;
        int             rc;

        if (!urb->transfer_buffer && urb->transfer_buffer_length)
                return -EINVAL;

        urbp = kmalloc (sizeof *urbp, mem_flags);
        if (!urbp)
                return -ENOMEM;
        urbp->urb = urb;

        dum = hcd_to_dummy (hcd);
        spin_lock_irqsave (&dum->lock, flags);
        rc = usb_hcd_link_urb_to_ep(hcd, urb);
        if (rc) {
                kfree(urbp);
                goto done;
        }

        if (!dum->udev) {
                dum->udev = urb->dev;
                usb_get_dev (dum->udev);
        } else if (unlikely (dum->udev != urb->dev))
                dev_err (dummy_dev(dum), "usb_device address has changed!\n");

        list_add_tail (&urbp->urbp_list, &dum->urbp_list);
        urb->hcpriv = urbp;
        if (usb_pipetype (urb->pipe) == PIPE_CONTROL)
                urb->error_count = 1;           /* mark as a new urb */

        /* kick the scheduler, it'll do the rest */
        if (!timer_pending (&dum->timer))
                mod_timer (&dum->timer, jiffies + 1);

 done:
        spin_unlock_irqrestore(&dum->lock, flags);
        return rc;
}

static int dummy_urb_dequeue(struct usb_hcd *hcd, struct urb *urb, int status)
{
        struct dummy    *dum;
        unsigned long   flags;
        int             rc;

        /* giveback happens automatically in timer callback,
         * so make sure the callback happens */
        dum = hcd_to_dummy (hcd);
        spin_lock_irqsave (&dum->lock, flags);

        rc = usb_hcd_check_unlink_urb(hcd, urb, status);
        if (!rc && dum->rh_state != DUMMY_RH_RUNNING &&
                        !list_empty(&dum->urbp_list))
                mod_timer (&dum->timer, jiffies);

        spin_unlock_irqrestore (&dum->lock, flags);
        return rc;
}

/* transfer up to a frame's worth; caller must own lock */
static int
transfer(struct dummy *dum, struct urb *urb, struct dummy_ep *ep, int limit,
                int *status)
{
        struct dummy_request    *req;

top:
        /* if there's no request queued, the device is NAKing; return */
        list_for_each_entry (req, &ep->queue, queue) {
                unsigned        host_len, dev_len, len;
                int             is_short, to_host;
                int             rescan = 0;

                /* 1..N packets of ep->ep.maxpacket each ... the last one
                 * may be short (including zero length).
                 *
                 * writer can send a zlp explicitly (length 0) or implicitly
                 * (length mod maxpacket zero, and 'zero' flag); they always
                 * terminate reads.
                 */
                host_len = urb->transfer_buffer_length - urb->actual_length;
                dev_len = req->req.length - req->req.actual;
                len = min (host_len, dev_len);

                /* FIXME update emulated data toggle too */

                to_host = usb_pipein (urb->pipe);
                if (unlikely (len == 0))
                        is_short = 1;
                else {
                        char            *ubuf, *rbuf;

                        /* not enough bandwidth left? */
                        if (limit < ep->ep.maxpacket && limit < len)
                                break;
                        len = min (len, (unsigned) limit);
                        if (len == 0)
                                break;

                        /* use an extra pass for the final short packet */
                        if (len > ep->ep.maxpacket) {
                                rescan = 1;
                                len -= (len % ep->ep.maxpacket);
                        }
                        is_short = (len % ep->ep.maxpacket) != 0;

                        /* else transfer packet(s) */
                        ubuf = urb->transfer_buffer + urb->actual_length;
                        rbuf = req->req.buf + req->req.actual;
                        if (to_host)
                                memcpy (ubuf, rbuf, len);
                        else
                                memcpy (rbuf, ubuf, len);
                        ep->last_io = jiffies;

                        limit -= len;
                        urb->actual_length += len;
                        req->req.actual += len;
                }

                /* short packets terminate, maybe with overflow/underflow.
                 * it's only really an error to write too much.
                 *
                 * partially filling a buffer optionally blocks queue advances
                 * (so completion handlers can clean up the queue) but we don't
                 * need to emulate such data-in-flight.
                 */
                if (is_short) {
                        if (host_len == dev_len) {
                                req->req.status = 0;
                                *status = 0;
                        } else if (to_host) {
                                req->req.status = 0;
                                if (dev_len > host_len)
                                        *status = -EOVERFLOW;
                                else
                                        *status = 0;
                        } else if (!to_host) {
                                *status = 0;
                                if (host_len > dev_len)
                                        req->req.status = -EOVERFLOW;
                                else
                                        req->req.status = 0;
                        }

                /* many requests terminate without a short packet */
                } else {
                        if (req->req.length == req->req.actual
                                        && !req->req.zero)
                                req->req.status = 0;
                        if (urb->transfer_buffer_length == urb->actual_length
                                        && !(urb->transfer_flags
                                                & URB_ZERO_PACKET))
                                *status = 0;
                }

                /* device side completion --> continuable */
                if (req->req.status != -EINPROGRESS) {
                        list_del_init (&req->queue);

                        spin_unlock (&dum->lock);
                        req->req.complete (&ep->ep, &req->req);
                        spin_lock (&dum->lock);

                        /* requests might have been unlinked... */
                        rescan = 1;
                }

                /* host side completion --> terminate */
                if (*status != -EINPROGRESS)
                        break;

                /* rescan to continue with any other queued i/o */
                if (rescan)
                        goto top;
        }
        return limit;
}

static int periodic_bytes (struct dummy *dum, struct dummy_ep *ep)
{
        int     limit = ep->ep.maxpacket;

        if (dum->gadget.speed == USB_SPEED_HIGH) {
                int     tmp;

                /* high bandwidth mode */
                tmp = le16_to_cpu(ep->desc->wMaxPacketSize);
                tmp = (tmp >> 11) & 0x03;
                tmp *= 8 /* applies to entire frame */;
                limit += limit * tmp;
        }
        return limit;
}

#define is_active(dum)  ((dum->port_status & \
                (USB_PORT_STAT_CONNECTION | USB_PORT_STAT_ENABLE | \
                        USB_PORT_STAT_SUSPEND)) \
                == (USB_PORT_STAT_CONNECTION | USB_PORT_STAT_ENABLE))

static struct dummy_ep *find_endpoint (struct dummy *dum, u8 address)
{
        int             i;

        if (!is_active (dum))
                return NULL;
        if ((address & ~USB_DIR_IN) == 0)
                return &dum->ep [0];
        for (i = 1; i < DUMMY_ENDPOINTS; i++) {
                struct dummy_ep *ep = &dum->ep [i];

                if (!ep->desc)
                        continue;
                if (ep->desc->bEndpointAddress == address)
                        return ep;
        }
        return NULL;
}

#undef is_active

#define Dev_Request     (USB_TYPE_STANDARD | USB_RECIP_DEVICE)
#define Dev_InRequest   (Dev_Request | USB_DIR_IN)
#define Intf_Request    (USB_TYPE_STANDARD | USB_RECIP_INTERFACE)
#define Intf_InRequest  (Intf_Request | USB_DIR_IN)
#define Ep_Request      (USB_TYPE_STANDARD | USB_RECIP_ENDPOINT)
#define Ep_InRequest    (Ep_Request | USB_DIR_IN)

/* drive both sides of the transfers; looks like irq handlers to
 * both drivers except the callbacks aren't in_irq().
 */
static void dummy_timer (unsigned long _dum)
{
        struct dummy            *dum = (struct dummy *) _dum;
        struct urbp             *urbp, *tmp;
        unsigned long           flags;
        int                     limit, total;
        int                     i;

        /* simplistic model for one frame's bandwidth */
        switch (dum->gadget.speed) {
        case USB_SPEED_LOW:
                total = 8/*bytes*/ * 12/*packets*/;
                break;
        case USB_SPEED_FULL:
                total = 64/*bytes*/ * 19/*packets*/;
                break;
        case USB_SPEED_HIGH:
                total = 512/*bytes*/ * 13/*packets*/ * 8/*uframes*/;
                break;
        default:
                dev_err (dummy_dev(dum), "bogus device speed\n");
                return;
        }

        /* FIXME if HZ != 1000 this will probably misbehave ... */

        /* look at each urb queued by the host side driver */
        spin_lock_irqsave (&dum->lock, flags);

        if (!dum->udev) {
                dev_err (dummy_dev(dum),
                                "timer fired with no URBs pending?\n");
                spin_unlock_irqrestore (&dum->lock, flags);
                return;
        }

        for (i = 0; i < DUMMY_ENDPOINTS; i++) {
                if (!ep_name [i])
                        break;
                dum->ep [i].already_seen = 0;
        }

restart:
        list_for_each_entry_safe (urbp, tmp, &dum->urbp_list, urbp_list) {
                struct urb              *urb;
                struct dummy_request    *req;
                u8                      address;
                struct dummy_ep         *ep = NULL;
                int                     type;
                int                     status = -EINPROGRESS;

                urb = urbp->urb;
                if (urb->unlinked)
                        goto return_urb;
                else if (dum->rh_state != DUMMY_RH_RUNNING)
                        continue;
                type = usb_pipetype (urb->pipe);

                /* used up this frame's non-periodic bandwidth?
                 * FIXME there's infinite bandwidth for control and
                 * periodic transfers ... unrealistic.
                 */
                if (total <= 0 && type == PIPE_BULK)
                        continue;

                /* find the gadget's ep for this request (if configured) */
                address = usb_pipeendpoint (urb->pipe);
                if (usb_pipein (urb->pipe))
                        address |= USB_DIR_IN;
                ep = find_endpoint(dum, address);
                if (!ep) {
                        /* set_configuration() disagreement */
                        dev_dbg (dummy_dev(dum),
                                "no ep configured for urb %p\n",
                                urb);
                        status = -EPROTO;
                        goto return_urb;
                }

                if (ep->already_seen)
                        continue;
                ep->already_seen = 1;
                if (ep == &dum->ep [0] && urb->error_count) {
                        ep->setup_stage = 1;    /* a new urb */
                        urb->error_count = 0;
                }
                if (ep->halted && !ep->setup_stage) {
                        /* NOTE: must not be iso! */
                        dev_dbg (dummy_dev(dum), "ep %s halted, urb %p\n",
                                        ep->ep.name, urb);
                        status = -EPIPE;
                        goto return_urb;
                }
                /* FIXME make sure both ends agree on maxpacket */

                /* handle control requests */
                if (ep == &dum->ep [0] && ep->setup_stage) {
                        struct usb_ctrlrequest          setup;
                        int                             value = 1;
                        struct dummy_ep                 *ep2;
                        unsigned                        w_index;
                        unsigned                        w_value;

                        setup = *(struct usb_ctrlrequest*) urb->setup_packet;
                        w_index = le16_to_cpu(setup.wIndex);
                        w_value = le16_to_cpu(setup.wValue);
                        if (le16_to_cpu(setup.wLength) !=
                                        urb->transfer_buffer_length) {
                                status = -EOVERFLOW;
                                goto return_urb;
                        }

                        /* paranoia, in case of stale queued data */
                        list_for_each_entry (req, &ep->queue, queue) {
                                list_del_init (&req->queue);
                                req->req.status = -EOVERFLOW;
                                dev_dbg (udc_dev(dum), "stale req = %p\n",
                                                req);

                                spin_unlock (&dum->lock);
                                req->req.complete (&ep->ep, &req->req);
                                spin_lock (&dum->lock);
                                ep->already_seen = 0;
                                goto restart;
                        }

                        /* gadget driver never sees set_address or operations
                         * on standard feature flags.  some hardware doesn't
                         * even expose them.
                         */
                        ep->last_io = jiffies;
                        ep->setup_stage = 0;
                        ep->halted = 0;
                        switch (setup.bRequest) {
                        case USB_REQ_SET_ADDRESS:
                                if (setup.bRequestType != Dev_Request)
                                        break;
                                dum->address = w_value;
                                status = 0;
                                dev_dbg (udc_dev(dum), "set_address = %d\n",
                                                w_value);
                                value = 0;
                                break;
                        case USB_REQ_SET_FEATURE:
                                if (setup.bRequestType == Dev_Request) {
                                        value = 0;
                                        switch (w_value) {
                                        case USB_DEVICE_REMOTE_WAKEUP:
                                                break;
                                        case USB_DEVICE_B_HNP_ENABLE:
                                                dum->gadget.b_hnp_enable = 1;
                                                break;
                                        case USB_DEVICE_A_HNP_SUPPORT:
                                                dum->gadget.a_hnp_support = 1;
                                                break;
                                        case USB_DEVICE_A_ALT_HNP_SUPPORT:
                                                dum->gadget.a_alt_hnp_support
                                                        = 1;
                                                break;
                                        default:
                                                value = -EOPNOTSUPP;
                                        }
                                        if (value == 0) {
                                                dum->devstatus |=
                                                        (1 << w_value);
                                                status = 0;
                                        }

                                } else if (setup.bRequestType == Ep_Request) {
                                        // endpoint halt
                                        ep2 = find_endpoint (dum, w_index);
                                        if (!ep2) {
                                                value = -EOPNOTSUPP;
                                                break;
                                        }
                                        ep2->halted = 1;
                                        value = 0;
                                        status = 0;
                                }
                                break;
                        case USB_REQ_CLEAR_FEATURE:
                                if (setup.bRequestType == Dev_Request) {
                                        switch (w_value) {
                                        case USB_DEVICE_REMOTE_WAKEUP:
                                                dum->devstatus &= ~(1 <<
                                                        USB_DEVICE_REMOTE_WAKEUP);
                                                value = 0;
                                                status = 0;
                                                break;
                                        default:
                                                value = -EOPNOTSUPP;
                                                break;
                                        }
                                } else if (setup.bRequestType == Ep_Request) {
                                        // endpoint halt
                                        ep2 = find_endpoint (dum, w_index);
                                        if (!ep2) {
                                                value = -EOPNOTSUPP;
                                                break;
                                        }
                                        ep2->halted = 0;
                                        value = 0;
                                        status = 0;
                                }
                                break;
                        case USB_REQ_GET_STATUS:
                                if (setup.bRequestType == Dev_InRequest
                                                || setup.bRequestType
                                                        == Intf_InRequest
                                                || setup.bRequestType
                                                        == Ep_InRequest
                                                ) {
                                        char *buf;

                                        // device: remote wakeup, selfpowered
                                        // interface: nothing
                                        // endpoint: halt
                                        buf = (char *)urb->transfer_buffer;
                                        if (urb->transfer_buffer_length > 0) {
                                                if (setup.bRequestType ==
                                                                Ep_InRequest) {
        ep2 = find_endpoint (dum, w_index);
        if (!ep2) {
                value = -EOPNOTSUPP;
                break;
        }
        buf [0] = ep2->halted;
                                                } else if (setup.bRequestType ==
                                                                Dev_InRequest) {
                                                        buf [0] = (u8)
                                                                dum->devstatus;
                                                } else
                                                        buf [0] = 0;
                                        }
                                        if (urb->transfer_buffer_length > 1)
                                                buf [1] = 0;
                                        urb->actual_length = min (2,
                                                urb->transfer_buffer_length);
                                        value = 0;
                                        status = 0;
                                }
                                break;
                        }

                        /* gadget driver handles all other requests.  block
                         * until setup() returns; no reentrancy issues etc.
                         */
                        if (value > 0) {
                                spin_unlock (&dum->lock);
                                value = dum->driver->setup (&dum->gadget,
                                                &setup);
                                spin_lock (&dum->lock);

                                if (value >= 0) {
                                        /* no delays (max 64KB data stage) */
                                        limit = 64*1024;
                                        goto treat_control_like_bulk;
                                }
                                /* error, see below */
                        }

                        if (value < 0) {
                                if (value != -EOPNOTSUPP)
                                        dev_dbg (udc_dev(dum),
                                                "setup --> %d\n",
                                                value);
                                status = -EPIPE;
                                urb->actual_length = 0;
                        }

                        goto return_urb;
                }

                /* non-control requests */
                limit = total;
                switch (usb_pipetype (urb->pipe)) {
                case PIPE_ISOCHRONOUS:
                        /* FIXME is it urb->interval since the last xfer?
                         * use urb->iso_frame_desc[i].
                         * complete whether or not ep has requests queued.
                         * report random errors, to debug drivers.
                         */
                        limit = max (limit, periodic_bytes (dum, ep));
                        status = -ENOSYS;
                        break;

                case PIPE_INTERRUPT:
                        /* FIXME is it urb->interval since the last xfer?
                         * this almost certainly polls too fast.
                         */
                        limit = max (limit, periodic_bytes (dum, ep));
                        /* FALLTHROUGH */

                // case PIPE_BULK:  case PIPE_CONTROL:
                default:
                treat_control_like_bulk:
                        ep->last_io = jiffies;
                        total = transfer(dum, urb, ep, limit, &status);
                        break;
                }

                /* incomplete transfer? */
                if (status == -EINPROGRESS)
                        continue;

return_urb:
                list_del (&urbp->urbp_list);
                kfree (urbp);
                if (ep)
                        ep->already_seen = ep->setup_stage = 0;

                usb_hcd_unlink_urb_from_ep(dummy_to_hcd(dum), urb);
                spin_unlock (&dum->lock);
                usb_hcd_giveback_urb(dummy_to_hcd(dum), urb, status);
                spin_lock (&dum->lock);

                goto restart;
        }

        if (list_empty (&dum->urbp_list)) {
                usb_put_dev (dum->udev);
                dum->udev = NULL;
        } else if (dum->rh_state == DUMMY_RH_RUNNING) {
                /* want a 1 msec delay here */
                mod_timer (&dum->timer, jiffies + msecs_to_jiffies(1));
        }

        spin_unlock_irqrestore (&dum->lock, flags);
}

/*-------------------------------------------------------------------------*/

#define PORT_C_MASK \
        ((USB_PORT_STAT_C_CONNECTION \
        | USB_PORT_STAT_C_ENABLE \
        | USB_PORT_STAT_C_SUSPEND \
        | USB_PORT_STAT_C_OVERCURRENT \
        | USB_PORT_STAT_C_RESET) << 16)

static int dummy_hub_status (struct usb_hcd *hcd, char *buf)
{
        struct dummy            *dum;
        unsigned long           flags;
        int                     retval = 0;

        dum = hcd_to_dummy (hcd);

        spin_lock_irqsave (&dum->lock, flags);
        if (!test_bit(HCD_FLAG_HW_ACCESSIBLE, &hcd->flags))
                goto done;

        if (dum->resuming && time_after_eq (jiffies, dum->re_timeout)) {
                dum->port_status |= (USB_PORT_STAT_C_SUSPEND << 16);
                dum->port_status &= ~USB_PORT_STAT_SUSPEND;
                set_link_state (dum);
        }

        if ((dum->port_status & PORT_C_MASK) != 0) {
                *buf = (1 << 1);
                dev_dbg (dummy_dev(dum), "port status 0x%08x has changes\n",
                                dum->port_status);
                retval = 1;
                if (dum->rh_state == DUMMY_RH_SUSPENDED)
                        usb_hcd_resume_root_hub (hcd);
        }
done:
        spin_unlock_irqrestore (&dum->lock, flags);
        return retval;
}

static inline void
hub_descriptor (struct usb_hub_descriptor *desc)
{
        memset (desc, 0, sizeof *desc);
        desc->bDescriptorType = 0x29;
        desc->bDescLength = 9;
        desc->wHubCharacteristics = cpu_to_le16(0x0001);
        desc->bNbrPorts = 1;
        desc->bitmap [0] = 0xff;
        desc->bitmap [1] = 0xff;
}

static int dummy_hub_control (
        struct usb_hcd  *hcd,
        u16             typeReq,
        u16             wValue,
        u16             wIndex,
        char            *buf,
        u16             wLength
) {
        struct dummy    *dum;
        int             retval = 0;
        unsigned long   flags;

        if (!test_bit(HCD_FLAG_HW_ACCESSIBLE, &hcd->flags))
                return -ETIMEDOUT;

        dum = hcd_to_dummy (hcd);
        spin_lock_irqsave (&dum->lock, flags);
        switch (typeReq) {
        case ClearHubFeature:
                break;
        case ClearPortFeature:
                switch (wValue) {
                case USB_PORT_FEAT_SUSPEND:
                        if (dum->port_status & USB_PORT_STAT_SUSPEND) {
                                /* 20msec resume signaling */
                                dum->resuming = 1;
                                dum->re_timeout = jiffies +
                                                msecs_to_jiffies(20);
                        }
                        break;
                case USB_PORT_FEAT_POWER:
                        if (dum->port_status & USB_PORT_STAT_POWER)
                                dev_dbg (dummy_dev(dum), "power-off\n");
                        /* FALLS THROUGH */
                default:
                        dum->port_status &= ~(1 << wValue);
                        set_link_state (dum);
                }
                break;
        case GetHubDescriptor:
                hub_descriptor ((struct usb_hub_descriptor *) buf);
                break;
        case GetHubStatus:
                *(__le32 *) buf = __constant_cpu_to_le32 (0);
                break;
        case GetPortStatus:
                if (wIndex != 1)
                        retval = -EPIPE;

                /* whoever resets or resumes must GetPortStatus to
                 * complete it!!
                 */
                if (dum->resuming &&
                                time_after_eq (jiffies, dum->re_timeout)) {
                        dum->port_status |= (USB_PORT_STAT_C_SUSPEND << 16);
                        dum->port_status &= ~USB_PORT_STAT_SUSPEND;
                }
                if ((dum->port_status & USB_PORT_STAT_RESET) != 0 &&
                                time_after_eq (jiffies, dum->re_timeout)) {
                        dum->port_status |= (USB_PORT_STAT_C_RESET << 16);
                        dum->port_status &= ~USB_PORT_STAT_RESET;
                        if (dum->pullup) {
                                dum->port_status |= USB_PORT_STAT_ENABLE;
                                /* give it the best speed we agree on */
                                dum->gadget.speed = dum->driver->speed;
                                dum->gadget.ep0->maxpacket = 64;
                                switch (dum->gadget.speed) {
                                case USB_SPEED_HIGH:
                                        dum->port_status |=
                                                USB_PORT_STAT_HIGH_SPEED;
                                        break;
                                case USB_SPEED_LOW:
                                        dum->gadget.ep0->maxpacket = 8;
                                        dum->port_status |=
                                                USB_PORT_STAT_LOW_SPEED;
                                        break;
                                default:
                                        dum->gadget.speed = USB_SPEED_FULL;
                                        break;
                                }
                        }
                }
                set_link_state (dum);
                ((__le16 *) buf)[0] = cpu_to_le16 (dum->port_status);
                ((__le16 *) buf)[1] = cpu_to_le16 (dum->port_status >> 16);
                break;
        case SetHubFeature:
                retval = -EPIPE;
                break;
        case SetPortFeature:
                switch (wValue) {
                case USB_PORT_FEAT_SUSPEND:
                        if (dum->active) {
                                dum->port_status |= USB_PORT_STAT_SUSPEND;

                                /* HNP would happen here; for now we
                                 * assume b_bus_req is always true.
                                 */
                                set_link_state (dum);
                                if (((1 << USB_DEVICE_B_HNP_ENABLE)
                                                & dum->devstatus) != 0)
                                        dev_dbg (dummy_dev(dum),
                                                        "no HNP yet!\n");
                        }
                        break;
                case USB_PORT_FEAT_POWER:
                        dum->port_status |= USB_PORT_STAT_POWER;
                        set_link_state (dum);
                        break;
                case USB_PORT_FEAT_RESET:
                        /* if it's already enabled, disable */
                        dum->port_status &= ~(USB_PORT_STAT_ENABLE
                                        | USB_PORT_STAT_LOW_SPEED
                                        | USB_PORT_STAT_HIGH_SPEED);
                        dum->devstatus = 0;
                        /* 50msec reset signaling */
                        dum->re_timeout = jiffies + msecs_to_jiffies(50);
                        /* FALLS THROUGH */
                default:
                        if ((dum->port_status & USB_PORT_STAT_POWER) != 0) {
                                dum->port_status |= (1 << wValue);
                                set_link_state (dum);
                        }
                }
                break;

        default:
                dev_dbg (dummy_dev(dum),
                        "hub control req%04x v%04x i%04x l%d\n",
                        typeReq, wValue, wIndex, wLength);

                /* "protocol stall" on error */
                retval = -EPIPE;
        }
        spin_unlock_irqrestore (&dum->lock, flags);

        if ((dum->port_status & PORT_C_MASK) != 0)
                usb_hcd_poll_rh_status (hcd);
        return retval;
}

static int dummy_bus_suspend (struct usb_hcd *hcd)
{
        struct dummy *dum = hcd_to_dummy (hcd);

        dev_dbg (&hcd->self.root_hub->dev, "%s\n", __func__);

        spin_lock_irq (&dum->lock);
        dum->rh_state = DUMMY_RH_SUSPENDED;
        set_link_state (dum);
        hcd->state = HC_STATE_SUSPENDED;
        spin_unlock_irq (&dum->lock);
        return 0;
}

static int dummy_bus_resume (struct usb_hcd *hcd)
{
        struct dummy *dum = hcd_to_dummy (hcd);
        int rc = 0;

        dev_dbg (&hcd->self.root_hub->dev, "%s\n", __func__);

        spin_lock_irq (&dum->lock);
        if (!test_bit(HCD_FLAG_HW_ACCESSIBLE, &hcd->flags)) {
                rc = -ESHUTDOWN;
        } else {
                dum->rh_state = DUMMY_RH_RUNNING;
                set_link_state (dum);
                if (!list_empty(&dum->urbp_list))
                        mod_timer (&dum->timer, jiffies);
                hcd->state = HC_STATE_RUNNING;
        }
        spin_unlock_irq (&dum->lock);
        return rc;
}

/*-------------------------------------------------------------------------*/

static inline ssize_t
show_urb (char *buf, size_t size, struct urb *urb)
{
        int ep = usb_pipeendpoint (urb->pipe);

        return snprintf (buf, size,
                "urb/%p %s ep%d%s%s len %d/%d\n",
                urb,
                ({ char *s;
                 switch (urb->dev->speed) {
                 case USB_SPEED_LOW:    s = "ls"; break;
                 case USB_SPEED_FULL:   s = "fs"; break;
                 case USB_SPEED_HIGH:   s = "hs"; break;
                 default:               s = "?"; break;
                 }; s; }),
                ep, ep ? (usb_pipein (urb->pipe) ? "in" : "out") : "",
                ({ char *s; \
                 switch (usb_pipetype (urb->pipe)) { \
                 case PIPE_CONTROL:     s = ""; break; \
                 case PIPE_BULK:        s = "-bulk"; break; \
                 case PIPE_INTERRUPT:   s = "-int"; break; \
                 default:               s = "-iso"; break; \
                }; s;}),
                urb->actual_length, urb->transfer_buffer_length);
}

static ssize_t
show_urbs (struct device *dev, struct device_attribute *attr, char *buf)
{
        struct usb_hcd          *hcd = dev_get_drvdata (dev);
        struct dummy            *dum = hcd_to_dummy (hcd);
        struct urbp             *urbp;
        size_t                  size = 0;
        unsigned long           flags;

        spin_lock_irqsave (&dum->lock, flags);
        list_for_each_entry (urbp, &dum->urbp_list, urbp_list) {
                size_t          temp;

                temp = show_urb (buf, PAGE_SIZE - size, urbp->urb);
                buf += temp;
                size += temp;
        }
        spin_unlock_irqrestore (&dum->lock, flags);

        return size;
}
static DEVICE_ATTR (urbs, S_IRUGO, show_urbs, NULL);

static int dummy_start (struct usb_hcd *hcd)
{
        struct dummy            *dum;

        dum = hcd_to_dummy (hcd);

        /*
         * MASTER side init ... we emulate a root hub that'll only ever
         * talk to one device (the slave side).  Also appears in sysfs,
         * just like more familiar pci-based HCDs.
         */
        spin_lock_init (&dum->lock);
        init_timer (&dum->timer);
        dum->timer.function = dummy_timer;
        dum->timer.data = (unsigned long) dum;
        dum->rh_state = DUMMY_RH_RUNNING;

        INIT_LIST_HEAD (&dum->urbp_list);

        hcd->power_budget = POWER_BUDGET;
        hcd->state = HC_STATE_RUNNING;
        hcd->uses_new_polling = 1;

#ifdef CONFIG_USB_OTG
        hcd->self.otg_port = 1;
#endif

        /* FIXME 'urbs' should be a per-device thing, maybe in usbcore */
        return device_create_file (dummy_dev(dum), &dev_attr_urbs);
}

static void dummy_stop (struct usb_hcd *hcd)
{
        struct dummy            *dum;

        dum = hcd_to_dummy (hcd);

        device_remove_file (dummy_dev(dum), &dev_attr_urbs);
        usb_gadget_unregister_driver (dum->driver);
        dev_info (dummy_dev(dum), "stopped\n");
}

/*-------------------------------------------------------------------------*/

static int dummy_h_get_frame (struct usb_hcd *hcd)
{
        return dummy_g_get_frame (NULL);
}

static const struct hc_driver dummy_hcd = {
        .description =          (char *) driver_name,
        .product_desc =         "Dummy host controller",
        .hcd_priv_size =        sizeof(struct dummy),

        .flags =                HCD_USB2,

        .start =                dummy_start,
        .stop =                 dummy_stop,

        .urb_enqueue =          dummy_urb_enqueue,
        .urb_dequeue =          dummy_urb_dequeue,

        .get_frame_number =     dummy_h_get_frame,

        .hub_status_data =      dummy_hub_status,
        .hub_control =          dummy_hub_control,
        .bus_suspend =          dummy_bus_suspend,
        .bus_resume =           dummy_bus_resume,
};

static int dummy_hcd_probe(struct platform_device *pdev)
{
        struct usb_hcd          *hcd;
        int                     retval;

        dev_info(&pdev->dev, "%s, driver " DRIVER_VERSION "\n", driver_desc);

        hcd = usb_create_hcd(&dummy_hcd, &pdev->dev, dev_name(&pdev->dev));
        if (!hcd)
                return -ENOMEM;
        the_controller = hcd_to_dummy (hcd);

        retval = usb_add_hcd(hcd, 0, 0);
        if (retval != 0) {
                usb_put_hcd (hcd);
                the_controller = NULL;
        }
        return retval;
}

static int dummy_hcd_remove (struct platform_device *pdev)
{
        struct usb_hcd          *hcd;

        hcd = platform_get_drvdata (pdev);
        usb_remove_hcd (hcd);
        usb_put_hcd (hcd);
        the_controller = NULL;
        return 0;
}

static int dummy_hcd_suspend (struct platform_device *pdev, pm_message_t state)
{
        struct usb_hcd          *hcd;
        struct dummy            *dum;
        int                     rc = 0;

        dev_dbg (&pdev->dev, "%s\n", __func__);

        hcd = platform_get_drvdata (pdev);
        dum = hcd_to_dummy (hcd);
        if (dum->rh_state == DUMMY_RH_RUNNING) {
                dev_warn(&pdev->dev, "Root hub isn't suspended!\n");
                rc = -EBUSY;
        } else
                clear_bit(HCD_FLAG_HW_ACCESSIBLE, &hcd->flags);
        return rc;
}

static int dummy_hcd_resume (struct platform_device *pdev)
{
        struct usb_hcd          *hcd;

        dev_dbg (&pdev->dev, "%s\n", __func__);

        hcd = platform_get_drvdata (pdev);
        set_bit(HCD_FLAG_HW_ACCESSIBLE, &hcd->flags);
        usb_hcd_poll_rh_status (hcd);
        return 0;
}

static struct platform_driver dummy_hcd_driver = {
        .probe          = dummy_hcd_probe,
        .remove         = dummy_hcd_remove,
        .suspend        = dummy_hcd_suspend,
        .resume         = dummy_hcd_resume,
        .driver         = {
                .name   = (char *) driver_name,
                .owner  = THIS_MODULE,
        },
};

/*-------------------------------------------------------------------------*/

static struct platform_device *the_udc_pdev;
static struct platform_device *the_hcd_pdev;

static int __init init (void)
{
        int     retval = -ENOMEM;

        if (usb_disabled ())
                return -ENODEV;

        the_hcd_pdev = platform_device_alloc(driver_name, -1);
        if (!the_hcd_pdev)
                return retval;
        the_udc_pdev = platform_device_alloc(gadget_name, -1);
        if (!the_udc_pdev)
                goto err_alloc_udc;

        retval = platform_driver_register(&dummy_hcd_driver);
        if (retval < 0)
                goto err_register_hcd_driver;
        retval = platform_driver_register(&dummy_udc_driver);
        if (retval < 0)
                goto err_register_udc_driver;

        retval = platform_device_add(the_hcd_pdev);
        if (retval < 0)
                goto err_add_hcd;
        retval = platform_device_add(the_udc_pdev);
        if (retval < 0)
                goto err_add_udc;
        return retval;

err_add_udc:
        platform_device_del(the_hcd_pdev);
err_add_hcd:
        platform_driver_unregister(&dummy_udc_driver);
err_register_udc_driver:
        platform_driver_unregister(&dummy_hcd_driver);
err_register_hcd_driver:
        platform_device_put(the_udc_pdev);
err_alloc_udc:
        platform_device_put(the_hcd_pdev);
        return retval;
}
module_init (init);

static void __exit cleanup (void)
{
        platform_device_unregister(the_udc_pdev);
        platform_device_unregister(the_hcd_pdev);
        platform_driver_unregister(&dummy_udc_driver);
        platform_driver_unregister(&dummy_hcd_driver);
}
module_exit (cleanup);