// SPDX-License-Identifier: GPL-2.0+
/*
 * 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 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 (device);
 *  - 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.
 *
 * Note: The emulation does not include isochronous transfers!
 */

#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 <linux/usb/hcd.h>
#include <linux/scatterlist.h>

#include <asm/byteorder.h>
#include <linux/io.h>
#include <asm/irq.h>
#include <asm/unaligned.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 */
#define POWER_BUDGET_3  900     /* in mA */

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");

struct dummy_hcd_module_parameters {
        bool is_super_speed;
        bool is_high_speed;
        unsigned int num;
};

static struct dummy_hcd_module_parameters mod_data = {
        .is_super_speed = false,
        .is_high_speed = true,
        .num = 1,
};
module_param_named(is_super_speed, mod_data.is_super_speed, bool, S_IRUGO);
MODULE_PARM_DESC(is_super_speed, "true to simulate SuperSpeed connection");
module_param_named(is_high_speed, mod_data.is_high_speed, bool, S_IRUGO);
MODULE_PARM_DESC(is_high_speed, "true to simulate HighSpeed connection");
module_param_named(num, mod_data.num, uint, S_IRUGO);
MODULE_PARM_DESC(num, "number of emulated controllers");
/*-------------------------------------------------------------------------*/

/* 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                        wedged:1;
        unsigned                        already_seen:1;
        unsigned                        setup_stage:1;
        unsigned                        stream_en: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 struct {
        const char *name;
        const struct usb_ep_caps caps;
} ep_info[] = {
#define EP_INFO(_name, _caps) \
        { \
                .name = _name, \
                .caps = _caps, \
        }

/* we don't provide isochronous endpoints since we don't support them */
#define TYPE_BULK_OR_INT        (USB_EP_CAPS_TYPE_BULK | USB_EP_CAPS_TYPE_INT)

        /* everyone has ep0 */
        EP_INFO(ep0name,
                USB_EP_CAPS(USB_EP_CAPS_TYPE_CONTROL, USB_EP_CAPS_DIR_ALL)),
        /* act like a pxa250: fifteen fixed function endpoints */
        EP_INFO("ep1in-bulk",
                USB_EP_CAPS(USB_EP_CAPS_TYPE_BULK, USB_EP_CAPS_DIR_IN)),
        EP_INFO("ep2out-bulk",
                USB_EP_CAPS(USB_EP_CAPS_TYPE_BULK, USB_EP_CAPS_DIR_OUT)),
/*
        EP_INFO("ep3in-iso",
                USB_EP_CAPS(USB_EP_CAPS_TYPE_ISO, USB_EP_CAPS_DIR_IN)),
        EP_INFO("ep4out-iso",
                USB_EP_CAPS(USB_EP_CAPS_TYPE_ISO, USB_EP_CAPS_DIR_OUT)),
*/
        EP_INFO("ep5in-int",
                USB_EP_CAPS(USB_EP_CAPS_TYPE_INT, USB_EP_CAPS_DIR_IN)),
        EP_INFO("ep6in-bulk",
                USB_EP_CAPS(USB_EP_CAPS_TYPE_BULK, USB_EP_CAPS_DIR_IN)),
        EP_INFO("ep7out-bulk",
                USB_EP_CAPS(USB_EP_CAPS_TYPE_BULK, USB_EP_CAPS_DIR_OUT)),
/*
        EP_INFO("ep8in-iso",
                USB_EP_CAPS(USB_EP_CAPS_TYPE_ISO, USB_EP_CAPS_DIR_IN)),
        EP_INFO("ep9out-iso",
                USB_EP_CAPS(USB_EP_CAPS_TYPE_ISO, USB_EP_CAPS_DIR_OUT)),
*/
        EP_INFO("ep10in-int",
                USB_EP_CAPS(USB_EP_CAPS_TYPE_INT, USB_EP_CAPS_DIR_IN)),
        EP_INFO("ep11in-bulk",
                USB_EP_CAPS(USB_EP_CAPS_TYPE_BULK, USB_EP_CAPS_DIR_IN)),
        EP_INFO("ep12out-bulk",
                USB_EP_CAPS(USB_EP_CAPS_TYPE_BULK, USB_EP_CAPS_DIR_OUT)),
/*
        EP_INFO("ep13in-iso",
                USB_EP_CAPS(USB_EP_CAPS_TYPE_ISO, USB_EP_CAPS_DIR_IN)),
        EP_INFO("ep14out-iso",
                USB_EP_CAPS(USB_EP_CAPS_TYPE_ISO, USB_EP_CAPS_DIR_OUT)),
*/
        EP_INFO("ep15in-int",
                USB_EP_CAPS(USB_EP_CAPS_TYPE_INT, USB_EP_CAPS_DIR_IN)),

        /* or like sa1100: two fixed function endpoints */
        EP_INFO("ep1out-bulk",
                USB_EP_CAPS(USB_EP_CAPS_TYPE_BULK, USB_EP_CAPS_DIR_OUT)),
        EP_INFO("ep2in-bulk",
                USB_EP_CAPS(USB_EP_CAPS_TYPE_BULK, USB_EP_CAPS_DIR_IN)),

        /* and now some generic EPs so we have enough in multi config */
        EP_INFO("ep-aout",
                USB_EP_CAPS(TYPE_BULK_OR_INT, USB_EP_CAPS_DIR_OUT)),
        EP_INFO("ep-bin",
                USB_EP_CAPS(TYPE_BULK_OR_INT, USB_EP_CAPS_DIR_IN)),
        EP_INFO("ep-cout",
                USB_EP_CAPS(TYPE_BULK_OR_INT, USB_EP_CAPS_DIR_OUT)),
        EP_INFO("ep-dout",
                USB_EP_CAPS(TYPE_BULK_OR_INT, USB_EP_CAPS_DIR_OUT)),
        EP_INFO("ep-ein",
                USB_EP_CAPS(TYPE_BULK_OR_INT, USB_EP_CAPS_DIR_IN)),
        EP_INFO("ep-fout",
                USB_EP_CAPS(TYPE_BULK_OR_INT, USB_EP_CAPS_DIR_OUT)),
        EP_INFO("ep-gin",
                USB_EP_CAPS(TYPE_BULK_OR_INT, USB_EP_CAPS_DIR_IN)),
        EP_INFO("ep-hout",
                USB_EP_CAPS(TYPE_BULK_OR_INT, USB_EP_CAPS_DIR_OUT)),
        EP_INFO("ep-iout",
                USB_EP_CAPS(TYPE_BULK_OR_INT, USB_EP_CAPS_DIR_OUT)),
        EP_INFO("ep-jin",
                USB_EP_CAPS(TYPE_BULK_OR_INT, USB_EP_CAPS_DIR_IN)),
        EP_INFO("ep-kout",
                USB_EP_CAPS(TYPE_BULK_OR_INT, USB_EP_CAPS_DIR_OUT)),
        EP_INFO("ep-lin",
                USB_EP_CAPS(TYPE_BULK_OR_INT, USB_EP_CAPS_DIR_IN)),
        EP_INFO("ep-mout",
                USB_EP_CAPS(TYPE_BULK_OR_INT, USB_EP_CAPS_DIR_OUT)),

#undef EP_INFO
};

#define DUMMY_ENDPOINTS ARRAY_SIZE(ep_info)

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

#define FIFO_SIZE               64

struct urbp {
        struct urb              *urb;
        struct list_head        urbp_list;
        struct sg_mapping_iter  miter;
        u32                     miter_started;
};


enum dummy_rh_state {
        DUMMY_RH_RESET,
        DUMMY_RH_SUSPENDED,
        DUMMY_RH_RUNNING
};

struct dummy_hcd {
        struct dummy                    *dum;
        enum dummy_rh_state             rh_state;
        struct timer_list               timer;
        u32                             port_status;
        u32                             old_status;
        unsigned long                   re_timeout;

        struct usb_device               *udev;
        struct list_head                urbp_list;
        struct urbp                     *next_frame_urbp;

        u32                             stream_en_ep;
        u8                              num_stream[30 / 2];

        unsigned                        active:1;
        unsigned                        old_active:1;
        unsigned                        resuming:1;
};

struct dummy {
        spinlock_t                      lock;

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

        /*
         * HOST side support
         */
        struct dummy_hcd                *hs_hcd;
        struct dummy_hcd                *ss_hcd;
};

static inline struct dummy_hcd *hcd_to_dummy_hcd(struct usb_hcd *hcd)
{
        return (struct dummy_hcd *) (hcd->hcd_priv);
}

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

static inline struct device *dummy_dev(struct dummy_hcd *dum)
{
        return dummy_hcd_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_hcd *gadget_to_dummy_hcd(struct usb_gadget *gadget)
{
        struct dummy *dum = container_of(gadget, struct dummy, gadget);
        if (dum->gadget.speed == USB_SPEED_SUPER)
                return dum->ss_hcd;
        else
                return dum->hs_hcd;
}

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

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

/* DEVICE/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);
                usb_gadget_giveback_request(&ep->ep, &req->req);
                spin_lock(&dum->lock);
        }
}

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

        /* 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 */
        for (i = 0; i < DUMMY_ENDPOINTS; ++i)
                nuke(dum, &dum->ep[i]);

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

/**
 * set_link_state_by_speed() - Sets the current state of the link according to
 *      the hcd speed
 * @dum_hcd: pointer to the dummy_hcd structure to update the link state for
 *
 * This function updates the port_status according to the link state and the
 * speed of the hcd.
 */
static void set_link_state_by_speed(struct dummy_hcd *dum_hcd)
{
        struct dummy *dum = dum_hcd->dum;

        if (dummy_hcd_to_hcd(dum_hcd)->speed == HCD_USB3) {
                if ((dum_hcd->port_status & USB_SS_PORT_STAT_POWER) == 0) {
                        dum_hcd->port_status = 0;
                } else if (!dum->pullup || dum->udc_suspended) {
                        /* UDC suspend must cause a disconnect */
                        dum_hcd->port_status &= ~(USB_PORT_STAT_CONNECTION |
                                                USB_PORT_STAT_ENABLE);
                        if ((dum_hcd->old_status &
                             USB_PORT_STAT_CONNECTION) != 0)
                                dum_hcd->port_status |=
                                        (USB_PORT_STAT_C_CONNECTION << 16);
                } else {
                        /* device is connected and not suspended */
                        dum_hcd->port_status |= (USB_PORT_STAT_CONNECTION |
                                                 USB_PORT_STAT_SPEED_5GBPS) ;
                        if ((dum_hcd->old_status &
                             USB_PORT_STAT_CONNECTION) == 0)
                                dum_hcd->port_status |=
                                        (USB_PORT_STAT_C_CONNECTION << 16);
                        if ((dum_hcd->port_status & USB_PORT_STAT_ENABLE) &&
                            (dum_hcd->port_status &
                             USB_PORT_STAT_LINK_STATE) == USB_SS_PORT_LS_U0 &&
                            dum_hcd->rh_state != DUMMY_RH_SUSPENDED)
                                dum_hcd->active = 1;
                }
        } else {
                if ((dum_hcd->port_status & USB_PORT_STAT_POWER) == 0) {
                        dum_hcd->port_status = 0;
                } else if (!dum->pullup || dum->udc_suspended) {
                        /* UDC suspend must cause a disconnect */
                        dum_hcd->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_hcd->old_status &
                             USB_PORT_STAT_CONNECTION) != 0)
                                dum_hcd->port_status |=
                                        (USB_PORT_STAT_C_CONNECTION << 16);
                } else {
                        dum_hcd->port_status |= USB_PORT_STAT_CONNECTION;
                        if ((dum_hcd->old_status &
                             USB_PORT_STAT_CONNECTION) == 0)
                                dum_hcd->port_status |=
                                        (USB_PORT_STAT_C_CONNECTION << 16);
                        if ((dum_hcd->port_status & USB_PORT_STAT_ENABLE) == 0)
                                dum_hcd->port_status &= ~USB_PORT_STAT_SUSPEND;
                        else if ((dum_hcd->port_status &
                                  USB_PORT_STAT_SUSPEND) == 0 &&
                                        dum_hcd->rh_state != DUMMY_RH_SUSPENDED)
                                dum_hcd->active = 1;
                }
        }
}

/* caller must hold lock */
static void set_link_state(struct dummy_hcd *dum_hcd)
        __must_hold(&dum->lock)
{
        struct dummy *dum = dum_hcd->dum;
        unsigned int power_bit;

        dum_hcd->active = 0;
        if (dum->pullup)
                if ((dummy_hcd_to_hcd(dum_hcd)->speed == HCD_USB3 &&
                     dum->gadget.speed != USB_SPEED_SUPER) ||
                    (dummy_hcd_to_hcd(dum_hcd)->speed != HCD_USB3 &&
                     dum->gadget.speed == USB_SPEED_SUPER))
                        return;

        set_link_state_by_speed(dum_hcd);
        power_bit = (dummy_hcd_to_hcd(dum_hcd)->speed == HCD_USB3 ?
                        USB_SS_PORT_STAT_POWER : USB_PORT_STAT_POWER);

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

        /* Currently !connected or in reset */
        if ((dum_hcd->port_status & power_bit) == 0 ||
                        (dum_hcd->port_status & USB_PORT_STAT_RESET) != 0) {
                unsigned int disconnect = power_bit &
                                dum_hcd->old_status & (~dum_hcd->port_status);
                unsigned int reset = USB_PORT_STAT_RESET &
                                (~dum_hcd->old_status) & dum_hcd->port_status;

                /* Report reset and disconnect events to the driver */
                if (dum->ints_enabled && (disconnect || reset)) {
                        stop_activity(dum);
                        ++dum->callback_usage;
                        spin_unlock(&dum->lock);
                        if (reset)
                                usb_gadget_udc_reset(&dum->gadget, dum->driver);
                        else
                                dum->driver->disconnect(&dum->gadget);
                        spin_lock(&dum->lock);
                        --dum->callback_usage;
                }
        } else if (dum_hcd->active != dum_hcd->old_active &&
                        dum->ints_enabled) {
                ++dum->callback_usage;
                spin_unlock(&dum->lock);
                if (dum_hcd->old_active && dum->driver->suspend)
                        dum->driver->suspend(&dum->gadget);
                else if (!dum_hcd->old_active &&  dum->driver->resume)
                        dum->driver->resume(&dum->gadget);
                spin_lock(&dum->lock);
                --dum->callback_usage;
        }

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

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

/* DEVICE/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_hcd        *dum_hcd;
        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)
                return -ESHUTDOWN;

        dum_hcd = gadget_to_dummy_hcd(&dum->gadget);
        if (!is_enabled(dum_hcd))
                return -ESHUTDOWN;

        /*
         * For HS/FS devices only bits 0..10 of the wMaxPacketSize represent the
         * maximum packet size.
         * For SS devices the wMaxPacketSize is limited by 1024.
         */
        max = usb_endpoint_maxp(desc);

        /* 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 (usb_endpoint_type(desc)) {
        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_SUPER:
                        if (max == 1024)
                                break;
                        goto done;
                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 */
                        fallthrough;
                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_SUPER:
                case USB_SPEED_HIGH:
                        if (max <= 1024)
                                break;
                        /* save a return statement */
                        fallthrough;
                case USB_SPEED_FULL:
                        if (max <= 64)
                                break;
                        /* save a return statement */
                        fallthrough;
                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_SUPER:
                case USB_SPEED_HIGH:
                        if (max <= 1024)
                                break;
                        /* save a return statement */
                        fallthrough;
                case USB_SPEED_FULL:
                        if (max <= 1023)
                                break;
                        /* save a return statement */
                        fallthrough;
                default:
                        goto done;
                }
                break;
        default:
                /* few chips support control except on ep0 */
                goto done;
        }

        _ep->maxpacket = max;
        if (usb_ss_max_streams(_ep->comp_desc)) {
                if (!usb_endpoint_xfer_bulk(desc)) {
                        dev_err(udc_dev(dum), "Can't enable stream support on "
                                        "non-bulk ep %s\n", _ep->name);
                        return -EINVAL;
                }
                ep->stream_en = 1;
        }
        ep->desc = desc;

        dev_dbg(udc_dev(dum), "enabled %s (ep%d%s-%s) maxpacket %d stream %s\n",
                _ep->name,
                desc->bEndpointAddress & 0x0f,
                (desc->bEndpointAddress & USB_DIR_IN) ? "in" : "out",
                usb_ep_type_string(usb_endpoint_type(desc)),
                max, ep->stream_en ? "enabled" : "disabled");

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

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

        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;
        ep->stream_en = 0;
        nuke(dum, ep);
        spin_unlock_irqrestore(&dum->lock, flags);

        dev_dbg(udc_dev(dum), "disabled %s\n", _ep->name);
        return 0;
}

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

        if (!_ep)
                return NULL;

        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_request    *req;

        if (!_ep || !_req) {
                WARN_ON(1);
                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;
        struct dummy_hcd        *dum_hcd;
        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);
        dum_hcd = gadget_to_dummy_hcd(&dum->gadget);
        if (!dum->driver || !is_enabled(dum_hcd))
                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;
                usb_gadget_giveback_request(_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);
                usb_gadget_giveback_request(_ep, _req);
        }
        local_irq_restore(flags);
        return retval;
}

static int
dummy_set_halt_and_wedge(struct usb_ep *_ep, int value, int wedged)
{
        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 = ep->wedged = 0;
        else if (ep->desc && (ep->desc->bEndpointAddress & USB_DIR_IN) &&
                        !list_empty(&ep->queue))
                return -EAGAIN;
        else {
                ep->halted = 1;
                if (wedged)
                        ep->wedged = 1;
        }
        /* FIXME clear emulated data toggle too */
        return 0;
}

static int
dummy_set_halt(struct usb_ep *_ep, int value)
{
        return dummy_set_halt_and_wedge(_ep, value, 0);
}

static int dummy_set_wedge(struct usb_ep *_ep)
{
        if (!_ep || _ep->name == ep0name)
                return -EINVAL;
        return dummy_set_halt_and_wedge(_ep, 1, 1);
}

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,
        .set_wedge      = dummy_set_wedge,
};

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

/* there are both host and device side versions of this call ... */
static int dummy_g_get_frame(struct usb_gadget *_gadget)
{
        struct timespec64 ts64;

        ktime_get_ts64(&ts64);
        return ts64.tv_nsec / NSEC_PER_MSEC;
}

static int dummy_wakeup(struct usb_gadget *_gadget)
{
        struct dummy_hcd *dum_hcd;

        dum_hcd = gadget_to_dummy_hcd(_gadget);
        if (!(dum_hcd->dum->devstatus & ((1 << USB_DEVICE_B_HNP_ENABLE)
                                | (1 << USB_DEVICE_REMOTE_WAKEUP))))
                return -EINVAL;
        if ((dum_hcd->port_status & USB_PORT_STAT_CONNECTION) == 0)
                return -ENOLINK;
        if ((dum_hcd->port_status & USB_PORT_STAT_SUSPEND) == 0 &&
                         dum_hcd->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_hcd->resuming = 1;
        dum_hcd->re_timeout = jiffies + msecs_to_jiffies(20);
        mod_timer(&dummy_hcd_to_hcd(dum_hcd)->rh_timer, dum_hcd->re_timeout);
        return 0;
}

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

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

static void dummy_udc_update_ep0(struct dummy *dum)
{
        if (dum->gadget.speed == USB_SPEED_SUPER)
                dum->ep[0].ep.maxpacket = 9;
        else
                dum->ep[0].ep.maxpacket = 64;
}

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

        dum = gadget_dev_to_dummy(&_gadget->dev);
        dum_hcd = gadget_to_dummy_hcd(_gadget);

        spin_lock_irqsave(&dum->lock, flags);
        dum->pullup = (value != 0);
        set_link_state(dum_hcd);
        if (value == 0) {
                /*
                 * Emulate synchronize_irq(): wait for callbacks to finish.
                 * This seems to be the best place to emulate the call to
                 * synchronize_irq() that's in usb_gadget_remove_driver().
                 * Doing it in dummy_udc_stop() would be too late since it
                 * is called after the unbind callback and unbind shouldn't
                 * be invoked until all the other callbacks are finished.
                 */
                while (dum->callback_usage > 0) {
                        spin_unlock_irqrestore(&dum->lock, flags);
                        usleep_range(1000, 2000);
                        spin_lock_irqsave(&dum->lock, flags);
                }
        }
        spin_unlock_irqrestore(&dum->lock, flags);

        usb_hcd_poll_rh_status(dummy_hcd_to_hcd(dum_hcd));
        return 0;
}

static void dummy_udc_set_speed(struct usb_gadget *_gadget,
                enum usb_device_speed speed)
{
        struct dummy    *dum;

        dum = gadget_dev_to_dummy(&_gadget->dev);
        dum->gadget.speed = speed;
        dummy_udc_update_ep0(dum);
}

static void dummy_udc_async_callbacks(struct usb_gadget *_gadget, bool enable)
{
        struct dummy    *dum = gadget_dev_to_dummy(&_gadget->dev);

        spin_lock_irq(&dum->lock);
        dum->ints_enabled = enable;
        spin_unlock_irq(&dum->lock);
}

static int dummy_udc_start(struct usb_gadget *g,
                struct usb_gadget_driver *driver);
static int dummy_udc_stop(struct usb_gadget *g);

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,
        .udc_start      = dummy_udc_start,
        .udc_stop       = dummy_udc_stop,
        .udc_set_speed  = dummy_udc_set_speed,
        .udc_async_callbacks = dummy_udc_async_callbacks,
};

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

/* "function" sysfs attribute */
static ssize_t function_show(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_RO(function);

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

/*
 * 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 device
 * for each driver that registers:  just add to a big root hub.
 */

static int dummy_udc_start(struct usb_gadget *g,
                struct usb_gadget_driver *driver)
{
        struct dummy_hcd        *dum_hcd = gadget_to_dummy_hcd(g);
        struct dummy            *dum = dum_hcd->dum;

        switch (g->speed) {
        /* All the speeds we support */
        case USB_SPEED_LOW:
        case USB_SPEED_FULL:

        case USB_SPEED_HIGH:
        case USB_SPEED_SUPER:
                break;
        default:
                dev_err(dummy_dev(dum_hcd), "Unsupported driver max speed %d\n",
                                driver->max_speed);
                return -EINVAL;
        }

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

        spin_lock_irq(&dum->lock);
        dum->devstatus = 0;
        dum->driver = driver;
        spin_unlock_irq(&dum->lock);

        return 0;
}

static int dummy_udc_stop(struct usb_gadget *g)
{
        struct dummy_hcd        *dum_hcd = gadget_to_dummy_hcd(g);
        struct dummy            *dum = dum_hcd->dum;

        spin_lock_irq(&dum->lock);
        dum->ints_enabled = 0;
        stop_activity(dum);
        dum->driver = NULL;
        spin_unlock_irq(&dum->lock);

        return 0;
}

#undef is_enabled

/* The gadget structure is stored inside the hcd structure and will be
 * released along with it. */
static void init_dummy_udc_hw(struct dummy *dum)
{
        int i;

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

                if (!ep_info[i].name)
                        break;
                ep->ep.name = ep_info[i].name;
                ep->ep.caps = ep_info[i].caps;
                ep->ep.ops = &dummy_ep_ops;
                list_add_tail(&ep->ep.ep_list, &dum->gadget.ep_list);
                ep->halted = ep->wedged = ep->already_seen =
                                ep->setup_stage = 0;
                usb_ep_set_maxpacket_limit(&ep->ep, ~0);
                ep->ep.max_streams = 16;
                ep->last_io = jiffies;
                ep->gadget = &dum->gadget;
                ep->desc = NULL;
                INIT_LIST_HEAD(&ep->queue);
        }

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

#ifdef CONFIG_USB_OTG
        dum->gadget.is_otg = 1;
#endif
}

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

        dum = *((void **)dev_get_platdata(&pdev->dev));
        /* Clear usb_gadget region for new registration to udc-core */
        memzero_explicit(&dum->gadget, sizeof(struct usb_gadget));
        dum->gadget.name = gadget_name;
        dum->gadget.ops = &dummy_ops;
        if (mod_data.is_super_speed)
                dum->gadget.max_speed = USB_SPEED_SUPER;
        else if (mod_data.is_high_speed)
                dum->gadget.max_speed = USB_SPEED_HIGH;
        else
                dum->gadget.max_speed = USB_SPEED_FULL;

        dum->gadget.dev.parent = &pdev->dev;
        init_dummy_udc_hw(dum);

        rc = usb_add_gadget_udc(&pdev->dev, &dum->gadget);
        if (rc < 0)
                goto err_udc;

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

err_dev:
        usb_del_gadget_udc(&dum->gadget);
err_udc:
        return rc;
}

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

        device_remove_file(&dum->gadget.dev, &dev_attr_function);
        usb_del_gadget_udc(&dum->gadget);
        return 0;
}

static void dummy_udc_pm(struct dummy *dum, struct dummy_hcd *dum_hcd,
                int suspend)
{
        spin_lock_irq(&dum->lock);
        dum->udc_suspended = suspend;
        set_link_state(dum_hcd);
        spin_unlock_irq(&dum->lock);
}

static int dummy_udc_suspend(struct platform_device *pdev, pm_message_t state)
{
        struct dummy            *dum = platform_get_drvdata(pdev);
        struct dummy_hcd        *dum_hcd = gadget_to_dummy_hcd(&dum->gadget);

        dev_dbg(&pdev->dev, "%s\n", __func__);
        dummy_udc_pm(dum, dum_hcd, 1);
        usb_hcd_poll_rh_status(dummy_hcd_to_hcd(dum_hcd));
        return 0;
}

static int dummy_udc_resume(struct platform_device *pdev)
{
        struct dummy            *dum = platform_get_drvdata(pdev);
        struct dummy_hcd        *dum_hcd = gadget_to_dummy_hcd(&dum->gadget);

        dev_dbg(&pdev->dev, "%s\n", __func__);
        dummy_udc_pm(dum, dum_hcd, 0);
        usb_hcd_poll_rh_status(dummy_hcd_to_hcd(dum_hcd));
        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   = gadget_name,
        },
};

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

static unsigned int dummy_get_ep_idx(const struct usb_endpoint_descriptor *desc)
{
        unsigned int index;

        index = usb_endpoint_num(desc) << 1;
        if (usb_endpoint_dir_in(desc))
                index |= 1;
        return index;
}

/* 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_ep_stream_en(struct dummy_hcd *dum_hcd, struct urb *urb)
{
        const struct usb_endpoint_descriptor *desc = &urb->ep->desc;
        u32 index;

        if (!usb_endpoint_xfer_bulk(desc))
                return 0;

        index = dummy_get_ep_idx(desc);
        return (1 << index) & dum_hcd->stream_en_ep;
}

/*
 * The max stream number is saved as a nibble so for the 30 possible endpoints
 * we only 15 bytes of memory. Therefore we are limited to max 16 streams (0
 * means we use only 1 stream). The maximum according to the spec is 16bit so
 * if the 16 stream limit is about to go, the array size should be incremented
 * to 30 elements of type u16.
 */
static int get_max_streams_for_pipe(struct dummy_hcd *dum_hcd,
                unsigned int pipe)
{
        int max_streams;

        max_streams = dum_hcd->num_stream[usb_pipeendpoint(pipe)];
        if (usb_pipeout(pipe))
                max_streams >>= 4;
        else
                max_streams &= 0xf;
        max_streams++;
        return max_streams;
}

static void set_max_streams_for_pipe(struct dummy_hcd *dum_hcd,
                unsigned int pipe, unsigned int streams)
{
        int max_streams;

        streams--;
        max_streams = dum_hcd->num_stream[usb_pipeendpoint(pipe)];
        if (usb_pipeout(pipe)) {
                streams <<= 4;
                max_streams &= 0xf;
        } else {
                max_streams &= 0xf0;
        }
        max_streams |= streams;
        dum_hcd->num_stream[usb_pipeendpoint(pipe)] = max_streams;
}

static int dummy_validate_stream(struct dummy_hcd *dum_hcd, struct urb *urb)
{
        unsigned int max_streams;
        int enabled;

        enabled = dummy_ep_stream_en(dum_hcd, urb);
        if (!urb->stream_id) {
                if (enabled)
                        return -EINVAL;
                return 0;
        }
        if (!enabled)
                return -EINVAL;

        max_streams = get_max_streams_for_pipe(dum_hcd,
                        usb_pipeendpoint(urb->pipe));
        if (urb->stream_id > max_streams) {
                dev_err(dummy_dev(dum_hcd), "Stream id %d is out of range.\n",
                                urb->stream_id);
                BUG();
                return -EINVAL;
        }
        return 0;
}

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

        urbp = kmalloc(sizeof *urbp, mem_flags);
        if (!urbp)
                return -ENOMEM;
        urbp->urb = urb;
        urbp->miter_started = 0;

        dum_hcd = hcd_to_dummy_hcd(hcd);
        spin_lock_irqsave(&dum_hcd->dum->lock, flags);

        rc = dummy_validate_stream(dum_hcd, urb);
        if (rc) {
                kfree(urbp);
                goto done;
        }

        rc = usb_hcd_link_urb_to_ep(hcd, urb);
        if (rc) {
                kfree(urbp);
                goto done;
        }

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

        list_add_tail(&urbp->urbp_list, &dum_hcd->urbp_list);
        urb->hcpriv = urbp;
        if (!dum_hcd->next_frame_urbp)
                dum_hcd->next_frame_urbp = 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_hcd->timer))
                mod_timer(&dum_hcd->timer, jiffies + 1);

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

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

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

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

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

static int dummy_perform_transfer(struct urb *urb, struct dummy_request *req,
                u32 len)
{
        void *ubuf, *rbuf;
        struct urbp *urbp = urb->hcpriv;
        int to_host;
        struct sg_mapping_iter *miter = &urbp->miter;
        u32 trans = 0;
        u32 this_sg;
        bool next_sg;

        to_host = usb_urb_dir_in(urb);
        rbuf = req->req.buf + req->req.actual;

        if (!urb->num_sgs) {
                ubuf = urb->transfer_buffer + urb->actual_length;
                if (to_host)
                        memcpy(ubuf, rbuf, len);
                else
                        memcpy(rbuf, ubuf, len);
                return len;
        }

        if (!urbp->miter_started) {
                u32 flags = SG_MITER_ATOMIC;

                if (to_host)
                        flags |= SG_MITER_TO_SG;
                else
                        flags |= SG_MITER_FROM_SG;

                sg_miter_start(miter, urb->sg, urb->num_sgs, flags);
                urbp->miter_started = 1;
        }
        next_sg = sg_miter_next(miter);
        if (next_sg == false) {
                WARN_ON_ONCE(1);
                return -EINVAL;
        }
        do {
                ubuf = miter->addr;
                this_sg = min_t(u32, len, miter->length);
                miter->consumed = this_sg;
                trans += this_sg;

                if (to_host)
                        memcpy(ubuf, rbuf, this_sg);
                else
                        memcpy(rbuf, ubuf, this_sg);
                len -= this_sg;

                if (!len)
                        break;
                next_sg = sg_miter_next(miter);
                if (next_sg == false) {
                        WARN_ON_ONCE(1);
                        return -EINVAL;
                }

                rbuf += this_sg;
        } while (1);

        sg_miter_stop(miter);
        return trans;
}

/* transfer up to a frame's worth; caller must own lock */
static int transfer(struct dummy_hcd *dum_hcd, struct urb *urb,
                struct dummy_ep *ep, int limit, int *status)
{
        struct dummy            *dum = dum_hcd->dum;
        struct dummy_request    *req;
        int                     sent = 0;

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;

                if (dummy_ep_stream_en(dum_hcd, urb)) {
                        if ((urb->stream_id != req->req.stream_id))
                                continue;
                }

                /* 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_urb_dir_in(urb);
                if (unlikely(len == 0))
                        is_short = 1;
                else {
                        /* not enough bandwidth left? */
                        if (limit < ep->ep.maxpacket && limit < len)
                                break;
                        len = min_t(unsigned, len, limit);
                        if (len == 0)
                                break;

                        /* send multiple of maxpacket first, then remainder */
                        if (len >= ep->ep.maxpacket) {
                                is_short = 0;
                                if (len % ep->ep.maxpacket)
                                        rescan = 1;
                                len -= len % ep->ep.maxpacket;
                        } else {
                                is_short = 1;
                        }

                        len = dummy_perform_transfer(urb, req, len);

                        ep->last_io = jiffies;
                        if ((int)len < 0) {
                                req->req.status = len;
                        } else {
                                limit -= len;
                                sent += 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 {
                                *status = 0;
                                if (host_len > dev_len)
                                        req->req.status = -EOVERFLOW;
                                else
                                        req->req.status = 0;
                        }

                /*
                 * many requests terminate without a short packet.
                 * send a zlp if demanded by flags.
                 */
                } else {
                        if (req->req.length == req->req.actual) {
                                if (req->req.zero && to_host)
                                        rescan = 1;
                                else
                                        req->req.status = 0;
                        }
                        if (urb->transfer_buffer_length == urb->actual_length) {
                                if (urb->transfer_flags & URB_ZERO_PACKET &&
                                    !to_host)
                                        rescan = 1;
                                else
                                        *status = 0;
                        }
                }

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

                        spin_unlock(&dum->lock);
                        usb_gadget_giveback_request(&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 sent;
}

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 = usb_endpoint_maxp_mult(ep->desc);
                tmp *= 8 /* applies to entire frame */;
                limit += limit * tmp;
        }
        if (dum->gadget.speed == USB_SPEED_SUPER) {
                switch (usb_endpoint_type(ep->desc)) {
                case USB_ENDPOINT_XFER_ISOC:
                        /* Sec. 4.4.8.2 USB3.0 Spec */
                        limit = 3 * 16 * 1024 * 8;
                        break;
                case USB_ENDPOINT_XFER_INT:
                        /* Sec. 4.4.7.2 USB3.0 Spec */
                        limit = 3 * 1024 * 8;
                        break;
                case USB_ENDPOINT_XFER_BULK:
                default:
                        break;
                }
        }
        return limit;
}

#define is_active(dum_hcd)      ((dum_hcd->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->gadget.speed == USB_SPEED_SUPER ?
                        dum->ss_hcd : dum->hs_hcd)))
                return NULL;
        if (!dum->ints_enabled)
                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)


/**
 * handle_control_request() - handles all control transfers
 * @dum_hcd: pointer to dummy (the_controller)
 * @urb: the urb request to handle
 * @setup: pointer to the setup data for a USB device control
 *       request
 * @status: pointer to request handling status
 *
 * Return 0 - if the request was handled
 *        1 - if the request wasn't handles
 *        error code on error
 */
static int handle_control_request(struct dummy_hcd *dum_hcd, struct urb *urb,
                                  struct usb_ctrlrequest *setup,
                                  int *status)
{
        struct dummy_ep         *ep2;
        struct dummy            *dum = dum_hcd->dum;
        int                     ret_val = 1;
        unsigned        w_index;
        unsigned        w_value;

        w_index = le16_to_cpu(setup->wIndex);
        w_value = le16_to_cpu(setup->wValue);
        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);
                ret_val = 0;
                break;
        case USB_REQ_SET_FEATURE:
                if (setup->bRequestType == Dev_Request) {
                        ret_val = 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;
                        case USB_DEVICE_U1_ENABLE:
                                if (dummy_hcd_to_hcd(dum_hcd)->speed ==
                                    HCD_USB3)
                                        w_value = USB_DEV_STAT_U1_ENABLED;
                                else
                                        ret_val = -EOPNOTSUPP;
                                break;
                        case USB_DEVICE_U2_ENABLE:
                                if (dummy_hcd_to_hcd(dum_hcd)->speed ==
                                    HCD_USB3)
                                        w_value = USB_DEV_STAT_U2_ENABLED;
                                else
                                        ret_val = -EOPNOTSUPP;
                                break;
                        case USB_DEVICE_LTM_ENABLE:
                                if (dummy_hcd_to_hcd(dum_hcd)->speed ==
                                    HCD_USB3)
                                        w_value = USB_DEV_STAT_LTM_ENABLED;
                                else
                                        ret_val = -EOPNOTSUPP;
                                break;
                        default:
                                ret_val = -EOPNOTSUPP;
                        }
                        if (ret_val == 0) {
                                dum->devstatus |= (1 << w_value);
                                *status = 0;
                        }
                } else if (setup->bRequestType == Ep_Request) {
                        /* endpoint halt */
                        ep2 = find_endpoint(dum, w_index);
                        if (!ep2 || ep2->ep.name == ep0name) {
                                ret_val = -EOPNOTSUPP;
                                break;
                        }
                        ep2->halted = 1;
                        ret_val = 0;
                        *status = 0;
                }
                break;
        case USB_REQ_CLEAR_FEATURE:
                if (setup->bRequestType == Dev_Request) {
                        ret_val = 0;
                        switch (w_value) {
                        case USB_DEVICE_REMOTE_WAKEUP:
                                w_value = USB_DEVICE_REMOTE_WAKEUP;
                                break;
                        case USB_DEVICE_U1_ENABLE:
                                if (dummy_hcd_to_hcd(dum_hcd)->speed ==
                                    HCD_USB3)
                                        w_value = USB_DEV_STAT_U1_ENABLED;
                                else
                                        ret_val = -EOPNOTSUPP;
                                break;
                        case USB_DEVICE_U2_ENABLE:
                                if (dummy_hcd_to_hcd(dum_hcd)->speed ==
                                    HCD_USB3)
                                        w_value = USB_DEV_STAT_U2_ENABLED;
                                else
                                        ret_val = -EOPNOTSUPP;
                                break;
                        case USB_DEVICE_LTM_ENABLE:
                                if (dummy_hcd_to_hcd(dum_hcd)->speed ==
                                    HCD_USB3)
                                        w_value = USB_DEV_STAT_LTM_ENABLED;
                                else
                                        ret_val = -EOPNOTSUPP;
                                break;
                        default:
                                ret_val = -EOPNOTSUPP;
                                break;
                        }
                        if (ret_val == 0) {
                                dum->devstatus &= ~(1 << w_value);
                                *status = 0;
                        }
                } else if (setup->bRequestType == Ep_Request) {
                        /* endpoint halt */
                        ep2 = find_endpoint(dum, w_index);
                        if (!ep2) {
                                ret_val = -EOPNOTSUPP;
                                break;
                        }
                        if (!ep2->wedged)
                                ep2->halted = 0;
                        ret_val = 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) {
                                                ret_val = -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_t(u32, 2,
                                urb->transfer_buffer_length);
                        ret_val = 0;
                        *status = 0;
                }
                break;
        }
        return ret_val;
}

/*
 * Drive both sides of the transfers; looks like irq handlers to both
 * drivers except that the callbacks are invoked from soft interrupt
 * context.
 */
static void dummy_timer(struct timer_list *t)
{
        struct dummy_hcd        *dum_hcd = from_timer(dum_hcd, t, timer);
        struct dummy            *dum = dum_hcd->dum;
        struct urbp             *urbp, *tmp;
        unsigned long           flags;
        int                     limit, total;
        int                     i;

        /* simplistic model for one frame's bandwidth */
        /* FIXME: account for transaction and packet overhead */
        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;
        case USB_SPEED_SUPER:
                /* Bus speed is 500000 bytes/ms, so use a little less */
                total = 490000;
                break;
        default:        /* Can't happen */
                dev_err(dummy_dev(dum_hcd), "bogus device speed\n");
                total = 0;
                break;
        }

        /* 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_hcd->udev) {
                dev_err(dummy_dev(dum_hcd),
                                "timer fired with no URBs pending?\n");
                spin_unlock_irqrestore(&dum->lock, flags);
                return;
        }
        dum_hcd->next_frame_urbp = NULL;

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

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

                /* stop when we reach URBs queued after the timer interrupt */
                if (urbp == dum_hcd->next_frame_urbp)
                        break;

                urb = urbp->urb;
                if (urb->unlinked)
                        goto return_urb;
                else if (dum_hcd->rh_state != DUMMY_RH_RUNNING)
                        continue;

                /* Used up this frame's bandwidth? */
                if (total <= 0)
                        continue;

                /* find the gadget's ep for this request (if configured) */
                address = usb_pipeendpoint (urb->pipe);
                if (usb_urb_dir_in(urb))
                        address |= USB_DIR_IN;
                ep = find_endpoint(dum, address);
                if (!ep) {
                        /* set_configuration() disagreement */
                        dev_dbg(dummy_dev(dum_hcd),
                                "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_hcd), "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;

                        setup = *(struct usb_ctrlrequest *) urb->setup_packet;
                        /* 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);
                                usb_gadget_giveback_request(&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;

                        value = handle_control_request(dum_hcd, urb, &setup,
                                                       &status);

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

                                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:
                        /*
                         * We don't support isochronous.  But if we did,
                         * here are some of the issues we'd have to face:
                         *
                         * 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 = -EINVAL;       /* fail all xfers */
                        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;

                default:
treat_control_like_bulk:
                        ep->last_io = jiffies;
                        total -= transfer(dum_hcd, 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_hcd_to_hcd(dum_hcd), urb);
                spin_unlock(&dum->lock);
                usb_hcd_giveback_urb(dummy_hcd_to_hcd(dum_hcd), urb, status);
                spin_lock(&dum->lock);

                goto restart;
        }

        if (list_empty(&dum_hcd->urbp_list)) {
                usb_put_dev(dum_hcd->udev);
                dum_hcd->udev = NULL;
        } else if (dum_hcd->rh_state == DUMMY_RH_RUNNING) {
                /* want a 1 msec delay here */
                mod_timer(&dum_hcd->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_hcd        *dum_hcd;
        unsigned long           flags;
        int                     retval = 0;

        dum_hcd = hcd_to_dummy_hcd(hcd);

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

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

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

/* usb 3.0 root hub device descriptor */
static struct {
        struct usb_bos_descriptor bos;
        struct usb_ss_cap_descriptor ss_cap;
} __packed usb3_bos_desc = {

        .bos = {
                .bLength                = USB_DT_BOS_SIZE,
                .bDescriptorType        = USB_DT_BOS,
                .wTotalLength           = cpu_to_le16(sizeof(usb3_bos_desc)),
                .bNumDeviceCaps         = 1,
        },
        .ss_cap = {
                .bLength                = USB_DT_USB_SS_CAP_SIZE,
                .bDescriptorType        = USB_DT_DEVICE_CAPABILITY,
                .bDevCapabilityType     = USB_SS_CAP_TYPE,
                .wSpeedSupported        = cpu_to_le16(USB_5GBPS_OPERATION),
                .bFunctionalitySupport  = ilog2(USB_5GBPS_OPERATION),
        },
};

static inline void
ss_hub_descriptor(struct usb_hub_descriptor *desc)
{
        memset(desc, 0, sizeof *desc);
        desc->bDescriptorType = USB_DT_SS_HUB;
        desc->bDescLength = 12;
        desc->wHubCharacteristics = cpu_to_le16(
                        HUB_CHAR_INDV_PORT_LPSM |
                        HUB_CHAR_COMMON_OCPM);
        desc->bNbrPorts = 1;
        desc->u.ss.bHubHdrDecLat = 0x04; /* Worst case: 0.4 micro sec*/
        desc->u.ss.DeviceRemovable = 0;
}

static inline void hub_descriptor(struct usb_hub_descriptor *desc)
{
        memset(desc, 0, sizeof *desc);
        desc->bDescriptorType = USB_DT_HUB;
        desc->bDescLength = 9;
        desc->wHubCharacteristics = cpu_to_le16(
                        HUB_CHAR_INDV_PORT_LPSM |
                        HUB_CHAR_COMMON_OCPM);
        desc->bNbrPorts = 1;
        desc->u.hs.DeviceRemovable[0] = 0;
        desc->u.hs.DeviceRemovable[1] = 0xff;   /* PortPwrCtrlMask */
}

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

        if (!HCD_HW_ACCESSIBLE(hcd))
                return -ETIMEDOUT;

        dum_hcd = hcd_to_dummy_hcd(hcd);

        spin_lock_irqsave(&dum_hcd->dum->lock, flags);
        switch (typeReq) {
        case ClearHubFeature:
                break;
        case ClearPortFeature:
                switch (wValue) {
                case USB_PORT_FEAT_SUSPEND:
                        if (hcd->speed == HCD_USB3) {
                                dev_dbg(dummy_dev(dum_hcd),
                                         "USB_PORT_FEAT_SUSPEND req not "
                                         "supported for USB 3.0 roothub\n");
                                goto error;
                        }
                        if (dum_hcd->port_status & USB_PORT_STAT_SUSPEND) {
                                /* 20msec resume signaling */
                                dum_hcd->resuming = 1;
                                dum_hcd->re_timeout = jiffies +
                                                msecs_to_jiffies(20);
                        }
                        break;
                case USB_PORT_FEAT_POWER:
                        dev_dbg(dummy_dev(dum_hcd), "power-off\n");
                        if (hcd->speed == HCD_USB3)
                                dum_hcd->port_status &= ~USB_SS_PORT_STAT_POWER;
                        else
                                dum_hcd->port_status &= ~USB_PORT_STAT_POWER;
                        set_link_state(dum_hcd);
                        break;
                case USB_PORT_FEAT_ENABLE:
                case USB_PORT_FEAT_C_ENABLE:
                case USB_PORT_FEAT_C_SUSPEND:
                        /* Not allowed for USB-3 */
                        if (hcd->speed == HCD_USB3)
                                goto error;
                        fallthrough;
                case USB_PORT_FEAT_C_CONNECTION:
                case USB_PORT_FEAT_C_RESET:
                        dum_hcd->port_status &= ~(1 << wValue);
                        set_link_state(dum_hcd);
                        break;
                default:
                /* Disallow INDICATOR and C_OVER_CURRENT */
                        goto error;
                }
                break;
        case GetHubDescriptor:
                if (hcd->speed == HCD_USB3 &&
                                (wLength < USB_DT_SS_HUB_SIZE ||
                                 wValue != (USB_DT_SS_HUB << 8))) {
                        dev_dbg(dummy_dev(dum_hcd),
                                "Wrong hub descriptor type for "
                                "USB 3.0 roothub.\n");
                        goto error;
                }
                if (hcd->speed == HCD_USB3)
                        ss_hub_descriptor((struct usb_hub_descriptor *) buf);
                else
                        hub_descriptor((struct usb_hub_descriptor *) buf);
                break;

        case DeviceRequest | USB_REQ_GET_DESCRIPTOR:
                if (hcd->speed != HCD_USB3)
                        goto error;

                if ((wValue >> 8) != USB_DT_BOS)
                        goto error;

                memcpy(buf, &usb3_bos_desc, sizeof(usb3_bos_desc));
                retval = sizeof(usb3_bos_desc);
                break;

        case GetHubStatus:
                *(__le32 *) buf = cpu_to_le32(0);
                break;
        case GetPortStatus:
                if (wIndex != 1)
                        retval = -EPIPE;

                /* whoever resets or resumes must GetPortStatus to
                 * complete it!!
                 */
                if (dum_hcd->resuming &&
                                time_after_eq(jiffies, dum_hcd->re_timeout)) {
                        dum_hcd->port_status |= (USB_PORT_STAT_C_SUSPEND << 16);
                        dum_hcd->port_status &= ~USB_PORT_STAT_SUSPEND;
                }
                if ((dum_hcd->port_status & USB_PORT_STAT_RESET) != 0 &&
                                time_after_eq(jiffies, dum_hcd->re_timeout)) {
                        dum_hcd->port_status |= (USB_PORT_STAT_C_RESET << 16);
                        dum_hcd->port_status &= ~USB_PORT_STAT_RESET;
                        if (dum_hcd->dum->pullup) {
                                dum_hcd->port_status |= USB_PORT_STAT_ENABLE;

                                if (hcd->speed < HCD_USB3) {
                                        switch (dum_hcd->dum->gadget.speed) {
                                        case USB_SPEED_HIGH:
                                                dum_hcd->port_status |=
                                                      USB_PORT_STAT_HIGH_SPEED;
                                                break;
                                        case USB_SPEED_LOW:
                                                dum_hcd->dum->gadget.ep0->
                                                        maxpacket = 8;
                                                dum_hcd->port_status |=
                                                        USB_PORT_STAT_LOW_SPEED;
                                                break;
                                        default:
                                                break;
                                        }
                                }
                        }
                }
                set_link_state(dum_hcd);
                ((__le16 *) buf)[0] = cpu_to_le16(dum_hcd->port_status);
                ((__le16 *) buf)[1] = cpu_to_le16(dum_hcd->port_status >> 16);
                break;
        case SetHubFeature:
                retval = -EPIPE;
                break;
        case SetPortFeature:
                switch (wValue) {
                case USB_PORT_FEAT_LINK_STATE:
                        if (hcd->speed != HCD_USB3) {
                                dev_dbg(dummy_dev(dum_hcd),
                                         "USB_PORT_FEAT_LINK_STATE req not "
                                         "supported for USB 2.0 roothub\n");
                                goto error;
                        }
                        /*
                         * Since this is dummy we don't have an actual link so
                         * there is nothing to do for the SET_LINK_STATE cmd
                         */
                        break;
                case USB_PORT_FEAT_U1_TIMEOUT:
                case USB_PORT_FEAT_U2_TIMEOUT:
                        /* TODO: add suspend/resume support! */
                        if (hcd->speed != HCD_USB3) {
                                dev_dbg(dummy_dev(dum_hcd),
                                         "USB_PORT_FEAT_U1/2_TIMEOUT req not "
                                         "supported for USB 2.0 roothub\n");
                                goto error;
                        }
                        break;
                case USB_PORT_FEAT_SUSPEND:
                        /* Applicable only for USB2.0 hub */
                        if (hcd->speed == HCD_USB3) {
                                dev_dbg(dummy_dev(dum_hcd),
                                         "USB_PORT_FEAT_SUSPEND req not "
                                         "supported for USB 3.0 roothub\n");
                                goto error;
                        }
                        if (dum_hcd->active) {
                                dum_hcd->port_status |= USB_PORT_STAT_SUSPEND;

                                /* HNP would happen here; for now we
                                 * assume b_bus_req is always true.
                                 */
                                set_link_state(dum_hcd);
                                if (((1 << USB_DEVICE_B_HNP_ENABLE)
                                                & dum_hcd->dum->devstatus) != 0)
                                        dev_dbg(dummy_dev(dum_hcd),
                                                        "no HNP yet!\n");
                        }
                        break;
                case USB_PORT_FEAT_POWER:
                        if (hcd->speed == HCD_USB3)
                                dum_hcd->port_status |= USB_SS_PORT_STAT_POWER;
                        else
                                dum_hcd->port_status |= USB_PORT_STAT_POWER;
                        set_link_state(dum_hcd);
                        break;
                case USB_PORT_FEAT_BH_PORT_RESET:
                        /* Applicable only for USB3.0 hub */
                        if (hcd->speed != HCD_USB3) {
                                dev_dbg(dummy_dev(dum_hcd),
                                         "USB_PORT_FEAT_BH_PORT_RESET req not "
                                         "supported for USB 2.0 roothub\n");
                                goto error;
                        }
                        fallthrough;
                case USB_PORT_FEAT_RESET:
                        if (!(dum_hcd->port_status & USB_PORT_STAT_CONNECTION))
                                break;
                        /* if it's already enabled, disable */
                        if (hcd->speed == HCD_USB3) {
                                dum_hcd->port_status =
                                        (USB_SS_PORT_STAT_POWER |
                                         USB_PORT_STAT_CONNECTION |
                                         USB_PORT_STAT_RESET);
                        } else {
                                dum_hcd->port_status &= ~(USB_PORT_STAT_ENABLE
                                        | USB_PORT_STAT_LOW_SPEED
                                        | USB_PORT_STAT_HIGH_SPEED);
                                dum_hcd->port_status |= USB_PORT_STAT_RESET;
                        }
                        /*
                         * We want to reset device status. All but the
                         * Self powered feature
                         */
                        dum_hcd->dum->devstatus &=
                                (1 << USB_DEVICE_SELF_POWERED);
                        /*
                         * FIXME USB3.0: what is the correct reset signaling
                         * interval? Is it still 50msec as for HS?
                         */
                        dum_hcd->re_timeout = jiffies + msecs_to_jiffies(50);
                        set_link_state(dum_hcd);
                        break;
                case USB_PORT_FEAT_C_CONNECTION:
                case USB_PORT_FEAT_C_RESET:
                case USB_PORT_FEAT_C_ENABLE:
                case USB_PORT_FEAT_C_SUSPEND:
                        /* Not allowed for USB-3, and ignored for USB-2 */
                        if (hcd->speed == HCD_USB3)
                                goto error;
                        break;
                default:
                /* Disallow TEST, INDICATOR, and C_OVER_CURRENT */
                        goto error;
                }
                break;
        case GetPortErrorCount:
                if (hcd->speed != HCD_USB3) {
                        dev_dbg(dummy_dev(dum_hcd),
                                 "GetPortErrorCount req not "
                                 "supported for USB 2.0 roothub\n");
                        goto error;
                }
                /* We'll always return 0 since this is a dummy hub */
                *(__le32 *) buf = cpu_to_le32(0);
                break;
        case SetHubDepth:
                if (hcd->speed != HCD_USB3) {
                        dev_dbg(dummy_dev(dum_hcd),
                                 "SetHubDepth req not supported for "
                                 "USB 2.0 roothub\n");
                        goto error;
                }
                break;
        default:
                dev_dbg(dummy_dev(dum_hcd),
                        "hub control req%04x v%04x i%04x l%d\n",
                        typeReq, wValue, wIndex, wLength);
error:
                /* "protocol stall" on error */
                retval = -EPIPE;
        }
        spin_unlock_irqrestore(&dum_hcd->dum->lock, flags);

        if ((dum_hcd->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_hcd *dum_hcd = hcd_to_dummy_hcd(hcd);

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

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

static int dummy_bus_resume(struct usb_hcd *hcd)
{
        struct dummy_hcd *dum_hcd = hcd_to_dummy_hcd(hcd);
        int rc = 0;

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

        spin_lock_irq(&dum_hcd->dum->lock);
        if (!HCD_HW_ACCESSIBLE(hcd)) {
                rc = -ESHUTDOWN;
        } else {
                dum_hcd->rh_state = DUMMY_RH_RUNNING;
                set_link_state(dum_hcd);
                if (!list_empty(&dum_hcd->urbp_list))
                        mod_timer(&dum_hcd->timer, jiffies);
                hcd->state = HC_STATE_RUNNING;
        }
        spin_unlock_irq(&dum_hcd->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 scnprintf(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;
                case USB_SPEED_SUPER:
                        s = "ss";
                        break;
                default:
                        s = "?";
                        break;
                 } s; }),
                ep, ep ? (usb_urb_dir_in(urb) ? "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 urbs_show(struct device *dev, struct device_attribute *attr,
                char *buf)
{
        struct usb_hcd          *hcd = dev_get_drvdata(dev);
        struct dummy_hcd        *dum_hcd = hcd_to_dummy_hcd(hcd);
        struct urbp             *urbp;
        size_t                  size = 0;
        unsigned long           flags;

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

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

        return size;
}
static DEVICE_ATTR_RO(urbs);

static int dummy_start_ss(struct dummy_hcd *dum_hcd)
{
        timer_setup(&dum_hcd->timer, dummy_timer, 0);
        dum_hcd->rh_state = DUMMY_RH_RUNNING;
        dum_hcd->stream_en_ep = 0;
        INIT_LIST_HEAD(&dum_hcd->urbp_list);
        dummy_hcd_to_hcd(dum_hcd)->power_budget = POWER_BUDGET_3;
        dummy_hcd_to_hcd(dum_hcd)->state = HC_STATE_RUNNING;
        dummy_hcd_to_hcd(dum_hcd)->uses_new_polling = 1;
#ifdef CONFIG_USB_OTG
        dummy_hcd_to_hcd(dum_hcd)->self.otg_port = 1;
#endif
        return 0;

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

static int dummy_start(struct usb_hcd *hcd)
{
        struct dummy_hcd        *dum_hcd = hcd_to_dummy_hcd(hcd);

        /*
         * HOST side init ... we emulate a root hub that'll only ever
         * talk to one device (the gadget side).  Also appears in sysfs,
         * just like more familiar pci-based HCDs.
         */
        if (!usb_hcd_is_primary_hcd(hcd))
                return dummy_start_ss(dum_hcd);

        spin_lock_init(&dum_hcd->dum->lock);
        timer_setup(&dum_hcd->timer, dummy_timer, 0);
        dum_hcd->rh_state = DUMMY_RH_RUNNING;

        INIT_LIST_HEAD(&dum_hcd->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_hcd), &dev_attr_urbs);
}

static void dummy_stop(struct usb_hcd *hcd)
{
        device_remove_file(dummy_dev(hcd_to_dummy_hcd(hcd)), &dev_attr_urbs);
        dev_info(dummy_dev(hcd_to_dummy_hcd(hcd)), "stopped\n");
}

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

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

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

        dum = *((void **)dev_get_platdata(hcd->self.controller));
        hcd->self.sg_tablesize = ~0;
        if (usb_hcd_is_primary_hcd(hcd)) {
                dum->hs_hcd = hcd_to_dummy_hcd(hcd);
                dum->hs_hcd->dum = dum;
                /*
                 * Mark the first roothub as being USB 2.0.
                 * The USB 3.0 roothub will be registered later by
                 * dummy_hcd_probe()
                 */
                hcd->speed = HCD_USB2;
                hcd->self.root_hub->speed = USB_SPEED_HIGH;
        } else {
                dum->ss_hcd = hcd_to_dummy_hcd(hcd);
                dum->ss_hcd->dum = dum;
                hcd->speed = HCD_USB3;
                hcd->self.root_hub->speed = USB_SPEED_SUPER;
        }
        return 0;
}

/* Change a group of bulk endpoints to support multiple stream IDs */
static int dummy_alloc_streams(struct usb_hcd *hcd, struct usb_device *udev,
        struct usb_host_endpoint **eps, unsigned int num_eps,
        unsigned int num_streams, gfp_t mem_flags)
{
        struct dummy_hcd *dum_hcd = hcd_to_dummy_hcd(hcd);
        unsigned long flags;
        int max_stream;
        int ret_streams = num_streams;
        unsigned int index;
        unsigned int i;

        if (!num_eps)
                return -EINVAL;

        spin_lock_irqsave(&dum_hcd->dum->lock, flags);
        for (i = 0; i < num_eps; i++) {
                index = dummy_get_ep_idx(&eps[i]->desc);
                if ((1 << index) & dum_hcd->stream_en_ep) {
                        ret_streams = -EINVAL;
                        goto out;
                }
                max_stream = usb_ss_max_streams(&eps[i]->ss_ep_comp);
                if (!max_stream) {
                        ret_streams = -EINVAL;
                        goto out;
                }
                if (max_stream < ret_streams) {
                        dev_dbg(dummy_dev(dum_hcd), "Ep 0x%x only supports %u "
                                        "stream IDs.\n",
                                        eps[i]->desc.bEndpointAddress,
                                        max_stream);
                        ret_streams = max_stream;
                }
        }

        for (i = 0; i < num_eps; i++) {
                index = dummy_get_ep_idx(&eps[i]->desc);
                dum_hcd->stream_en_ep |= 1 << index;
                set_max_streams_for_pipe(dum_hcd,
                                usb_endpoint_num(&eps[i]->desc), ret_streams);
        }
out:
        spin_unlock_irqrestore(&dum_hcd->dum->lock, flags);
        return ret_streams;
}

/* Reverts a group of bulk endpoints back to not using stream IDs. */
static int dummy_free_streams(struct usb_hcd *hcd, struct usb_device *udev,
        struct usb_host_endpoint **eps, unsigned int num_eps,
        gfp_t mem_flags)
{
        struct dummy_hcd *dum_hcd = hcd_to_dummy_hcd(hcd);
        unsigned long flags;
        int ret;
        unsigned int index;
        unsigned int i;

        spin_lock_irqsave(&dum_hcd->dum->lock, flags);
        for (i = 0; i < num_eps; i++) {
                index = dummy_get_ep_idx(&eps[i]->desc);
                if (!((1 << index) & dum_hcd->stream_en_ep)) {
                        ret = -EINVAL;
                        goto out;
                }
        }

        for (i = 0; i < num_eps; i++) {
                index = dummy_get_ep_idx(&eps[i]->desc);
                dum_hcd->stream_en_ep &= ~(1 << index);
                set_max_streams_for_pipe(dum_hcd,
                                usb_endpoint_num(&eps[i]->desc), 0);
        }
        ret = 0;
out:
        spin_unlock_irqrestore(&dum_hcd->dum->lock, flags);
        return ret;
}

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

        .reset =                dummy_setup,
        .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,

        .alloc_streams =        dummy_alloc_streams,
        .free_streams =         dummy_free_streams,
};

static int dummy_hcd_probe(struct platform_device *pdev)
{
        struct dummy            *dum;
        struct usb_hcd          *hs_hcd;
        struct usb_hcd          *ss_hcd;
        int                     retval;

        dev_info(&pdev->dev, "%s, driver " DRIVER_VERSION "\n", driver_desc);
        dum = *((void **)dev_get_platdata(&pdev->dev));

        if (mod_data.is_super_speed)
                dummy_hcd.flags = HCD_USB3 | HCD_SHARED;
        else if (mod_data.is_high_speed)
                dummy_hcd.flags = HCD_USB2;
        else
                dummy_hcd.flags = HCD_USB11;
        hs_hcd = usb_create_hcd(&dummy_hcd, &pdev->dev, dev_name(&pdev->dev));
        if (!hs_hcd)
                return -ENOMEM;
        hs_hcd->has_tt = 1;

        retval = usb_add_hcd(hs_hcd, 0, 0);
        if (retval)
                goto put_usb2_hcd;

        if (mod_data.is_super_speed) {
                ss_hcd = usb_create_shared_hcd(&dummy_hcd, &pdev->dev,
                                        dev_name(&pdev->dev), hs_hcd);
                if (!ss_hcd) {
                        retval = -ENOMEM;
                        goto dealloc_usb2_hcd;
                }

                retval = usb_add_hcd(ss_hcd, 0, 0);
                if (retval)
                        goto put_usb3_hcd;
        }
        return 0;

put_usb3_hcd:
        usb_put_hcd(ss_hcd);
dealloc_usb2_hcd:
        usb_remove_hcd(hs_hcd);
put_usb2_hcd:
        usb_put_hcd(hs_hcd);
        dum->hs_hcd = dum->ss_hcd = NULL;
        return retval;
}

static int dummy_hcd_remove(struct platform_device *pdev)
{
        struct dummy            *dum;

        dum = hcd_to_dummy_hcd(platform_get_drvdata(pdev))->dum;

        if (dum->ss_hcd) {
                usb_remove_hcd(dummy_hcd_to_hcd(dum->ss_hcd));
                usb_put_hcd(dummy_hcd_to_hcd(dum->ss_hcd));
        }

        usb_remove_hcd(dummy_hcd_to_hcd(dum->hs_hcd));
        usb_put_hcd(dummy_hcd_to_hcd(dum->hs_hcd));

        dum->hs_hcd = NULL;
        dum->ss_hcd = NULL;

        return 0;
}

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

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

        hcd = platform_get_drvdata(pdev);
        dum_hcd = hcd_to_dummy_hcd(hcd);
        if (dum_hcd->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   = driver_name,
        },
};

/*-------------------------------------------------------------------------*/
#define MAX_NUM_UDC     32
static struct platform_device *the_udc_pdev[MAX_NUM_UDC];
static struct platform_device *the_hcd_pdev[MAX_NUM_UDC];

static int __init init(void)
{
        int     retval = -ENOMEM;
        int     i;
        struct  dummy *dum[MAX_NUM_UDC] = {};

        if (usb_disabled())
                return -ENODEV;

        if (!mod_data.is_high_speed && mod_data.is_super_speed)
                return -EINVAL;

        if (mod_data.num < 1 || mod_data.num > MAX_NUM_UDC) {
                pr_err("Number of emulated UDC must be in range of 1...%d\n",
                                MAX_NUM_UDC);
                return -EINVAL;
        }

        for (i = 0; i < mod_data.num; i++) {
                the_hcd_pdev[i] = platform_device_alloc(driver_name, i);
                if (!the_hcd_pdev[i]) {
                        i--;
                        while (i >= 0)
                                platform_device_put(the_hcd_pdev[i--]);
                        return retval;
                }
        }
        for (i = 0; i < mod_data.num; i++) {
                the_udc_pdev[i] = platform_device_alloc(gadget_name, i);
                if (!the_udc_pdev[i]) {
                        i--;
                        while (i >= 0)
                                platform_device_put(the_udc_pdev[i--]);
                        goto err_alloc_udc;
                }
        }
        for (i = 0; i < mod_data.num; i++) {
                dum[i] = kzalloc(sizeof(struct dummy), GFP_KERNEL);
                if (!dum[i]) {
                        retval = -ENOMEM;
                        goto err_add_pdata;
                }
                retval = platform_device_add_data(the_hcd_pdev[i], &dum[i],
                                sizeof(void *));
                if (retval)
                        goto err_add_pdata;
                retval = platform_device_add_data(the_udc_pdev[i], &dum[i],
                                sizeof(void *));
                if (retval)
                        goto err_add_pdata;
        }

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

        for (i = 0; i < mod_data.num; i++) {
                retval = platform_device_add(the_hcd_pdev[i]);
                if (retval < 0) {
                        i--;
                        while (i >= 0)
                                platform_device_del(the_hcd_pdev[i--]);
                        goto err_add_hcd;
                }
        }
        for (i = 0; i < mod_data.num; i++) {
                if (!dum[i]->hs_hcd ||
                                (!dum[i]->ss_hcd && mod_data.is_super_speed)) {
                        /*
                         * The hcd was added successfully but its probe
                         * function failed for some reason.
                         */
                        retval = -EINVAL;
                        goto err_add_udc;
                }
        }

        for (i = 0; i < mod_data.num; i++) {
                retval = platform_device_add(the_udc_pdev[i]);
                if (retval < 0) {
                        i--;
                        while (i >= 0)
                                platform_device_del(the_udc_pdev[i--]);
                        goto err_add_udc;
                }
        }

        for (i = 0; i < mod_data.num; i++) {
                if (!platform_get_drvdata(the_udc_pdev[i])) {
                        /*
                         * The udc was added successfully but its probe
                         * function failed for some reason.
                         */
                        retval = -EINVAL;
                        goto err_probe_udc;
                }
        }
        return retval;

err_probe_udc:
        for (i = 0; i < mod_data.num; i++)
                platform_device_del(the_udc_pdev[i]);
err_add_udc:
        for (i = 0; i < mod_data.num; i++)
                platform_device_del(the_hcd_pdev[i]);
err_add_hcd:
        platform_driver_unregister(&dummy_udc_driver);
err_register_udc_driver:
        platform_driver_unregister(&dummy_hcd_driver);
err_add_pdata:
        for (i = 0; i < mod_data.num; i++)
                kfree(dum[i]);
        for (i = 0; i < mod_data.num; i++)
                platform_device_put(the_udc_pdev[i]);
err_alloc_udc:
        for (i = 0; i < mod_data.num; i++)
                platform_device_put(the_hcd_pdev[i]);
        return retval;
}
module_init(init);

static void __exit cleanup(void)
{
        int i;

        for (i = 0; i < mod_data.num; i++) {
                struct dummy *dum;

                dum = *((void **)dev_get_platdata(&the_udc_pdev[i]->dev));

                platform_device_unregister(the_udc_pdev[i]);
                platform_device_unregister(the_hcd_pdev[i]);
                kfree(dum);
        }
        platform_driver_unregister(&dummy_udc_driver);
        platform_driver_unregister(&dummy_hcd_driver);
}
module_exit(cleanup);