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dummy_hcd.c

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


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

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

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


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


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

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

static const char gadget_name [] = "dummy_udc";

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

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

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

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

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

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

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

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

static const char ep0name [] = "ep0";

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

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

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

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

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

#define FIFO_SIZE       64

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


enum dummy_rh_state {
      DUMMY_RH_RESET,
      DUMMY_RH_SUSPENDED,
      DUMMY_RH_RUNNING
};

struct dummy {
      spinlock_t              lock;

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

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

      struct usb_device       *udev;
      struct list_head        urbp_list;
};

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

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

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

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

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

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

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

static struct dummy                 *the_controller;

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

/* SLAVE/GADGET SIDE UTILITY ROUTINES */

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

      .alloc_request    = dummy_alloc_request,
      .free_request     = dummy_free_request,

      .queue            = dummy_queue,
      .dequeue    = dummy_dequeue,

      .set_halt   = dummy_set_halt,
};

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

      dum->devstatus = 0;

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

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

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

      dum->driver = driver;
      dum->gadget.dev.driver = &driver->driver;
      dev_dbg (udc_dev(dum), "binding gadget driver '%s'\n",
                  driver->driver.name);
      if ((retval = driver->bind (&dum->gadget)) != 0)
            goto err_bind_gadget;

      driver->driver.bus = dum->gadget.dev.parent->bus;
      if ((retval = driver_register (&driver->driver)) != 0)
            goto err_register;
      if ((retval = device_bind_driver (&dum->gadget.dev)) != 0)
            goto err_bind_driver;

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

      usb_hcd_poll_rh_status (dummy_to_hcd (dum));
      return 0;

err_bind_driver:
      driver_unregister (&driver->driver);
err_register:
      if (driver->unbind)
            driver->unbind (&dum->gadget);
      spin_lock_irq (&dum->lock);
      dum->pullup = 0;
      set_link_state (dum);
      spin_unlock_irq (&dum->lock);
err_bind_gadget:
      dum->driver = NULL;
      dum->gadget.dev.driver = NULL;
      return retval;
}
EXPORT_SYMBOL (usb_gadget_register_driver);

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

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

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

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

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

      device_release_driver (&dum->gadget.dev);
      driver_unregister (&driver->driver);

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

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

#undef is_enabled

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

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


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

      usb_put_hcd (dummy_to_hcd (dum));
}

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

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

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

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

      usb_get_hcd (dummy_to_hcd (dum));

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

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

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

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

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

      pdev->dev.power.power_state = state;
      usb_hcd_poll_rh_status (dummy_to_hcd (dum));
      return 0;
}

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

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

      pdev->dev.power.power_state = PMSG_ON;
      usb_hcd_poll_rh_status (dummy_to_hcd (dum));
      return 0;
}

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

            /* FIXME update emulated data toggle too */

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

#undef is_active

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

                  goto return_urb;
            }

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

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

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

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

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

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

            goto restart;
      }

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

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

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

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

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

      dum = hcd_to_dummy (hcd);

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

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

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

static inline void
hub_descriptor (struct usb_hub_descriptor *desc)
{
      memset (desc, 0, sizeof *desc);
      desc->bDescriptorType = 0x29;
      desc->bDescLength = 9;
      desc->wHubCharacteristics = (__force __u16)
                  (__constant_cpu_to_le16 (0x0001));
      desc->bNbrPorts = 1;
      desc->bitmap [0] = 0xff;
      desc->bitmap [1] = 0xff;
}

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

      dum = hcd_to_dummy (hcd);

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

      INIT_LIST_HEAD (&dum->urbp_list);

      /* only show a low-power port: just 8mA */
      hcd->power_budget = 8;
      hcd->state = HC_STATE_RUNNING;
      hcd->uses_new_polling = 1;

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

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

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

      dum = hcd_to_dummy (hcd);

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

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

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

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

      .flags =          HCD_USB2,

      .start =          dummy_start,
      .stop =                 dummy_stop,

      .urb_enqueue =          dummy_urb_enqueue,
      .urb_dequeue =          dummy_urb_dequeue,

      .get_frame_number =     dummy_h_get_frame,

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

/* These don't need to do anything because the pdev structures are
 * statically allocated. */
static void
dummy_udc_release (struct device *dev) {}

static void
dummy_hcd_release (struct device *dev) {}

static struct platform_device       the_udc_pdev = {
      .name       = (char *) gadget_name,
      .id         = -1,
      .dev        = {
            .release    = dummy_udc_release,
      },
};

static struct platform_device       the_hcd_pdev = {
      .name       = (char *) driver_name,
      .id         = -1,
      .dev        = {
            .release    = dummy_hcd_release,
      },
};

static int __init init (void)
{
      int   retval;

      if (usb_disabled ())
            return -ENODEV;

      retval = platform_driver_register (&dummy_hcd_driver);
      if (retval < 0)
            return retval;

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

      retval = platform_device_register (&the_hcd_pdev);
      if (retval < 0)
            goto err_register_hcd;

      retval = platform_device_register (&the_udc_pdev);
      if (retval < 0)
            goto err_register_udc;
      return retval;

err_register_udc:
      platform_device_unregister (&the_hcd_pdev);
err_register_hcd:
      platform_driver_unregister (&dummy_udc_driver);
err_register_udc_driver:
      platform_driver_unregister (&dummy_hcd_driver);
      return retval;
}
module_init (init);

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

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